linux/fs/btrfs/scrub.c

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2011, 2012 STRATO. All rights reserved.
*/
#include <linux/blkdev.h>
#include <linux/ratelimit.h>
#include <linux/sched/mm.h>
#include <crypto/hash.h>
#include "ctree.h"
btrfs: handle empty block_group removal for async discard block_group removal is a little tricky. It can race with the extent allocator, the cleaner thread, and balancing. The current path is for a block_group to be added to the unused_bgs list. Then, when the cleaner thread comes around, it starts a transaction and then proceeds with removing the block_group. Extents that are pinned are subsequently removed from the pinned trees and then eventually a discard is issued for the entire block_group. Async discard introduces another player into the game, the discard workqueue. While it has none of the racing issues, the new problem is ensuring we don't leave free space untrimmed prior to forgetting the block_group. This is handled by placing fully free block_groups on a separate discard queue. This is necessary to maintain discarding order as in the future we will slowly trim even fully free block_groups. The ordering helps us make progress on the same block_group rather than say the last fully freed block_group or needing to search through the fully freed block groups at the beginning of a list and insert after. The new order of events is a fully freed block group gets placed on the unused discard queue first. Once it's processed, it will be placed on the unusued_bgs list and then the original sequence of events will happen, just without the final whole block_group discard. The mount flags can change when processing unused_bgs, so when flipping from DISCARD to DISCARD_ASYNC, the unused_bgs must be punted to the discard_list to be trimmed. If we flip off DISCARD_ASYNC, we punt free block groups on the discard_list to the unused_bg queue which will do the final discard for us. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Dennis Zhou <dennis@kernel.org> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-14 08:22:15 +08:00
#include "discard.h"
#include "volumes.h"
#include "disk-io.h"
#include "ordered-data.h"
#include "transaction.h"
#include "backref.h"
#include "extent_io.h"
#include "dev-replace.h"
#include "check-integrity.h"
#include "rcu-string.h"
#include "raid56.h"
#include "block-group.h"
btrfs: implement log-structured superblock for ZONED mode Superblock (and its copies) is the only data structure in btrfs which has a fixed location on a device. Since we cannot overwrite in a sequential write required zone, we cannot place superblock in the zone. One easy solution is limiting superblock and copies to be placed only in conventional zones. However, this method has two downsides: one is reduced number of superblock copies. The location of the second copy of superblock is 256GB, which is in a sequential write required zone on typical devices in the market today. So, the number of superblock and copies is limited to be two. Second downside is that we cannot support devices which have no conventional zones at all. To solve these two problems, we employ superblock log writing. It uses two adjacent zones as a circular buffer to write updated superblocks. Once the first zone is filled up, start writing into the second one. Then, when both zones are filled up and before starting to write to the first zone again, it reset the first zone. We can determine the position of the latest superblock by reading write pointer information from a device. One corner case is when both zones are full. For this situation, we read out the last superblock of each zone, and compare them to determine which zone is older. The following zones are reserved as the circular buffer on ZONED btrfs. - The primary superblock: zones 0 and 1 - The first copy: zones 16 and 17 - The second copy: zones 1024 or zone at 256GB which is minimum, and next to it If these reserved zones are conventional, superblock is written fixed at the start of the zone without logging. Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-10 19:26:14 +08:00
#include "zoned.h"
/*
* This is only the first step towards a full-features scrub. It reads all
* extent and super block and verifies the checksums. In case a bad checksum
* is found or the extent cannot be read, good data will be written back if
* any can be found.
*
* Future enhancements:
* - In case an unrepairable extent is encountered, track which files are
* affected and report them
* - track and record media errors, throw out bad devices
* - add a mode to also read unallocated space
*/
struct scrub_block;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
struct scrub_ctx;
/*
* the following three values only influence the performance.
* The last one configures the number of parallel and outstanding I/O
* operations. The first two values configure an upper limit for the number
* of (dynamically allocated) pages that are added to a bio.
*/
#define SCRUB_PAGES_PER_RD_BIO 32 /* 128k per bio */
#define SCRUB_PAGES_PER_WR_BIO 32 /* 128k per bio */
#define SCRUB_BIOS_PER_SCTX 64 /* 8MB per device in flight */
/*
* the following value times PAGE_SIZE needs to be large enough to match the
* largest node/leaf/sector size that shall be supported.
* Values larger than BTRFS_STRIPE_LEN are not supported.
*/
#define SCRUB_MAX_PAGES_PER_BLOCK 16 /* 64k per node/leaf/sector */
struct scrub_recover {
refcount_t refs;
struct btrfs_bio *bbio;
u64 map_length;
};
struct scrub_page {
struct scrub_block *sblock;
struct page *page;
struct btrfs_device *dev;
2014-11-06 17:20:58 +08:00
struct list_head list;
u64 flags; /* extent flags */
u64 generation;
u64 logical;
u64 physical;
u64 physical_for_dev_replace;
atomic_t refs;
u8 mirror_num;
int have_csum:1;
int io_error:1;
u8 csum[BTRFS_CSUM_SIZE];
struct scrub_recover *recover;
};
struct scrub_bio {
int index;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
struct scrub_ctx *sctx;
struct btrfs_device *dev;
struct bio *bio;
blk_status_t status;
u64 logical;
u64 physical;
#if SCRUB_PAGES_PER_WR_BIO >= SCRUB_PAGES_PER_RD_BIO
struct scrub_page *pagev[SCRUB_PAGES_PER_WR_BIO];
#else
struct scrub_page *pagev[SCRUB_PAGES_PER_RD_BIO];
#endif
int page_count;
int next_free;
struct btrfs_work work;
};
struct scrub_block {
struct scrub_page *pagev[SCRUB_MAX_PAGES_PER_BLOCK];
int page_count;
atomic_t outstanding_pages;
refcount_t refs; /* free mem on transition to zero */
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
struct scrub_ctx *sctx;
2014-11-06 17:20:58 +08:00
struct scrub_parity *sparity;
struct {
unsigned int header_error:1;
unsigned int checksum_error:1;
unsigned int no_io_error_seen:1;
unsigned int generation_error:1; /* also sets header_error */
2014-11-06 17:20:58 +08:00
/* The following is for the data used to check parity */
/* It is for the data with checksum */
unsigned int data_corrected:1;
};
struct btrfs_work work;
};
2014-11-06 17:20:58 +08:00
/* Used for the chunks with parity stripe such RAID5/6 */
struct scrub_parity {
struct scrub_ctx *sctx;
struct btrfs_device *scrub_dev;
u64 logic_start;
u64 logic_end;
int nsectors;
u32 stripe_len;
2014-11-06 17:20:58 +08:00
refcount_t refs;
2014-11-06 17:20:58 +08:00
struct list_head spages;
/* Work of parity check and repair */
struct btrfs_work work;
/* Mark the parity blocks which have data */
unsigned long *dbitmap;
/*
* Mark the parity blocks which have data, but errors happen when
* read data or check data
*/
unsigned long *ebitmap;
unsigned long bitmap[];
2014-11-06 17:20:58 +08:00
};
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
struct scrub_ctx {
struct scrub_bio *bios[SCRUB_BIOS_PER_SCTX];
struct btrfs_fs_info *fs_info;
int first_free;
int curr;
atomic_t bios_in_flight;
atomic_t workers_pending;
spinlock_t list_lock;
wait_queue_head_t list_wait;
struct list_head csum_list;
atomic_t cancel_req;
int readonly;
int pages_per_rd_bio;
int is_dev_replace;
u64 write_pointer;
struct scrub_bio *wr_curr_bio;
struct mutex wr_lock;
int pages_per_wr_bio; /* <= SCRUB_PAGES_PER_WR_BIO */
struct btrfs_device *wr_tgtdev;
bool flush_all_writes;
/*
* statistics
*/
struct btrfs_scrub_progress stat;
spinlock_t stat_lock;
Btrfs: scrub, fix sleep in atomic context My previous patch "Btrfs: fix scrub race leading to use-after-free" introduced the possibility to sleep in an atomic context, which happens when the scrub_lock mutex is held at the time scrub_pending_bio_dec() is called - this function can be called under an atomic context. Chris ran into this in a debug kernel which gave the following trace: [ 1928.950319] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:621 [ 1928.967334] in_atomic(): 1, irqs_disabled(): 0, pid: 149670, name: fsstress [ 1928.981324] INFO: lockdep is turned off. [ 1928.989244] CPU: 24 PID: 149670 Comm: fsstress Tainted: G W 3.19.0-rc7-mason+ #41 [ 1929.006418] Hardware name: ZTSYSTEMS Echo Ridge T4 /A9DRPF-10D, BIOS 1.07 05/10/2012 [ 1929.022207] ffffffff81a22cf8 ffff881076e03b78 ffffffff816b8dd9 ffff881076e03b78 [ 1929.037267] ffff880d8e828710 ffff881076e03ba8 ffffffff810856c4 ffff881076e03bc8 [ 1929.052315] 0000000000000000 000000000000026d ffffffff81a22cf8 ffff881076e03bd8 [ 1929.067381] Call Trace: [ 1929.072344] <IRQ> [<ffffffff816b8dd9>] dump_stack+0x4f/0x6e [ 1929.083968] [<ffffffff810856c4>] ___might_sleep+0x174/0x230 [ 1929.095352] [<ffffffff810857d2>] __might_sleep+0x52/0x90 [ 1929.106223] [<ffffffff816bb68f>] mutex_lock_nested+0x2f/0x3b0 [ 1929.117951] [<ffffffff810ab37d>] ? trace_hardirqs_on+0xd/0x10 [ 1929.129708] [<ffffffffa05dc838>] scrub_pending_bio_dec+0x38/0x70 [btrfs] [ 1929.143370] [<ffffffffa05dd0e0>] scrub_parity_bio_endio+0x50/0x70 [btrfs] [ 1929.157191] [<ffffffff812fa603>] bio_endio+0x53/0xa0 [ 1929.167382] [<ffffffffa05f96bc>] rbio_orig_end_io+0x7c/0xa0 [btrfs] [ 1929.180161] [<ffffffffa05f97ba>] raid_write_parity_end_io+0x5a/0x80 [btrfs] [ 1929.194318] [<ffffffff812fa603>] bio_endio+0x53/0xa0 [ 1929.204496] [<ffffffff8130401b>] blk_update_request+0x1eb/0x450 [ 1929.216569] [<ffffffff81096e58>] ? trigger_load_balance+0x78/0x500 [ 1929.229176] [<ffffffff8144c74d>] scsi_end_request+0x3d/0x1f0 [ 1929.240740] [<ffffffff8144ccac>] scsi_io_completion+0xac/0x5b0 [ 1929.252654] [<ffffffff81441c50>] scsi_finish_command+0xf0/0x150 [ 1929.264725] [<ffffffff8144d317>] scsi_softirq_done+0x147/0x170 [ 1929.276635] [<ffffffff8130ace6>] blk_done_softirq+0x86/0xa0 [ 1929.288014] [<ffffffff8105d92e>] __do_softirq+0xde/0x600 [ 1929.298885] [<ffffffff8105df6d>] irq_exit+0xbd/0xd0 (...) Fix this by using a reference count on the scrub context structure instead of locking the scrub_lock mutex. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-02-10 05:14:24 +08:00
/*
* Use a ref counter to avoid use-after-free issues. Scrub workers
* decrement bios_in_flight and workers_pending and then do a wakeup
* on the list_wait wait queue. We must ensure the main scrub task
* doesn't free the scrub context before or while the workers are
* doing the wakeup() call.
*/
refcount_t refs;
};
struct scrub_warning {
struct btrfs_path *path;
u64 extent_item_size;
const char *errstr;
u64 physical;
u64 logical;
struct btrfs_device *dev;
};
struct full_stripe_lock {
struct rb_node node;
u64 logical;
u64 refs;
struct mutex mutex;
};
static int scrub_setup_recheck_block(struct scrub_block *original_sblock,
struct scrub_block *sblocks_for_recheck);
static void scrub_recheck_block(struct btrfs_fs_info *fs_info,
struct scrub_block *sblock,
int retry_failed_mirror);
static void scrub_recheck_block_checksum(struct scrub_block *sblock);
static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad,
struct scrub_block *sblock_good);
static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
struct scrub_block *sblock_good,
int page_num, int force_write);
static void scrub_write_block_to_dev_replace(struct scrub_block *sblock);
static int scrub_write_page_to_dev_replace(struct scrub_block *sblock,
int page_num);
static int scrub_checksum_data(struct scrub_block *sblock);
static int scrub_checksum_tree_block(struct scrub_block *sblock);
static int scrub_checksum_super(struct scrub_block *sblock);
static void scrub_block_put(struct scrub_block *sblock);
static void scrub_page_get(struct scrub_page *spage);
static void scrub_page_put(struct scrub_page *spage);
2014-11-06 17:20:58 +08:00
static void scrub_parity_get(struct scrub_parity *sparity);
static void scrub_parity_put(struct scrub_parity *sparity);
static int scrub_pages(struct scrub_ctx *sctx, u64 logical, u32 len,
u64 physical, struct btrfs_device *dev, u64 flags,
u64 gen, int mirror_num, u8 *csum,
u64 physical_for_dev_replace);
static void scrub_bio_end_io(struct bio *bio);
static void scrub_bio_end_io_worker(struct btrfs_work *work);
static void scrub_block_complete(struct scrub_block *sblock);
static void scrub_remap_extent(struct btrfs_fs_info *fs_info,
u64 extent_logical, u32 extent_len,
u64 *extent_physical,
struct btrfs_device **extent_dev,
int *extent_mirror_num);
static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx,
struct scrub_page *spage);
static void scrub_wr_submit(struct scrub_ctx *sctx);
static void scrub_wr_bio_end_io(struct bio *bio);
static void scrub_wr_bio_end_io_worker(struct btrfs_work *work);
Btrfs: scrub, fix sleep in atomic context My previous patch "Btrfs: fix scrub race leading to use-after-free" introduced the possibility to sleep in an atomic context, which happens when the scrub_lock mutex is held at the time scrub_pending_bio_dec() is called - this function can be called under an atomic context. Chris ran into this in a debug kernel which gave the following trace: [ 1928.950319] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:621 [ 1928.967334] in_atomic(): 1, irqs_disabled(): 0, pid: 149670, name: fsstress [ 1928.981324] INFO: lockdep is turned off. [ 1928.989244] CPU: 24 PID: 149670 Comm: fsstress Tainted: G W 3.19.0-rc7-mason+ #41 [ 1929.006418] Hardware name: ZTSYSTEMS Echo Ridge T4 /A9DRPF-10D, BIOS 1.07 05/10/2012 [ 1929.022207] ffffffff81a22cf8 ffff881076e03b78 ffffffff816b8dd9 ffff881076e03b78 [ 1929.037267] ffff880d8e828710 ffff881076e03ba8 ffffffff810856c4 ffff881076e03bc8 [ 1929.052315] 0000000000000000 000000000000026d ffffffff81a22cf8 ffff881076e03bd8 [ 1929.067381] Call Trace: [ 1929.072344] <IRQ> [<ffffffff816b8dd9>] dump_stack+0x4f/0x6e [ 1929.083968] [<ffffffff810856c4>] ___might_sleep+0x174/0x230 [ 1929.095352] [<ffffffff810857d2>] __might_sleep+0x52/0x90 [ 1929.106223] [<ffffffff816bb68f>] mutex_lock_nested+0x2f/0x3b0 [ 1929.117951] [<ffffffff810ab37d>] ? trace_hardirqs_on+0xd/0x10 [ 1929.129708] [<ffffffffa05dc838>] scrub_pending_bio_dec+0x38/0x70 [btrfs] [ 1929.143370] [<ffffffffa05dd0e0>] scrub_parity_bio_endio+0x50/0x70 [btrfs] [ 1929.157191] [<ffffffff812fa603>] bio_endio+0x53/0xa0 [ 1929.167382] [<ffffffffa05f96bc>] rbio_orig_end_io+0x7c/0xa0 [btrfs] [ 1929.180161] [<ffffffffa05f97ba>] raid_write_parity_end_io+0x5a/0x80 [btrfs] [ 1929.194318] [<ffffffff812fa603>] bio_endio+0x53/0xa0 [ 1929.204496] [<ffffffff8130401b>] blk_update_request+0x1eb/0x450 [ 1929.216569] [<ffffffff81096e58>] ? trigger_load_balance+0x78/0x500 [ 1929.229176] [<ffffffff8144c74d>] scsi_end_request+0x3d/0x1f0 [ 1929.240740] [<ffffffff8144ccac>] scsi_io_completion+0xac/0x5b0 [ 1929.252654] [<ffffffff81441c50>] scsi_finish_command+0xf0/0x150 [ 1929.264725] [<ffffffff8144d317>] scsi_softirq_done+0x147/0x170 [ 1929.276635] [<ffffffff8130ace6>] blk_done_softirq+0x86/0xa0 [ 1929.288014] [<ffffffff8105d92e>] __do_softirq+0xde/0x600 [ 1929.298885] [<ffffffff8105df6d>] irq_exit+0xbd/0xd0 (...) Fix this by using a reference count on the scrub context structure instead of locking the scrub_lock mutex. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-02-10 05:14:24 +08:00
static void scrub_put_ctx(struct scrub_ctx *sctx);
static inline int scrub_is_page_on_raid56(struct scrub_page *spage)
{
return spage->recover &&
(spage->recover->bbio->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK);
}
static void scrub_pending_bio_inc(struct scrub_ctx *sctx)
{
refcount_inc(&sctx->refs);
atomic_inc(&sctx->bios_in_flight);
}
static void scrub_pending_bio_dec(struct scrub_ctx *sctx)
{
atomic_dec(&sctx->bios_in_flight);
wake_up(&sctx->list_wait);
Btrfs: scrub, fix sleep in atomic context My previous patch "Btrfs: fix scrub race leading to use-after-free" introduced the possibility to sleep in an atomic context, which happens when the scrub_lock mutex is held at the time scrub_pending_bio_dec() is called - this function can be called under an atomic context. Chris ran into this in a debug kernel which gave the following trace: [ 1928.950319] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:621 [ 1928.967334] in_atomic(): 1, irqs_disabled(): 0, pid: 149670, name: fsstress [ 1928.981324] INFO: lockdep is turned off. [ 1928.989244] CPU: 24 PID: 149670 Comm: fsstress Tainted: G W 3.19.0-rc7-mason+ #41 [ 1929.006418] Hardware name: ZTSYSTEMS Echo Ridge T4 /A9DRPF-10D, BIOS 1.07 05/10/2012 [ 1929.022207] ffffffff81a22cf8 ffff881076e03b78 ffffffff816b8dd9 ffff881076e03b78 [ 1929.037267] ffff880d8e828710 ffff881076e03ba8 ffffffff810856c4 ffff881076e03bc8 [ 1929.052315] 0000000000000000 000000000000026d ffffffff81a22cf8 ffff881076e03bd8 [ 1929.067381] Call Trace: [ 1929.072344] <IRQ> [<ffffffff816b8dd9>] dump_stack+0x4f/0x6e [ 1929.083968] [<ffffffff810856c4>] ___might_sleep+0x174/0x230 [ 1929.095352] [<ffffffff810857d2>] __might_sleep+0x52/0x90 [ 1929.106223] [<ffffffff816bb68f>] mutex_lock_nested+0x2f/0x3b0 [ 1929.117951] [<ffffffff810ab37d>] ? trace_hardirqs_on+0xd/0x10 [ 1929.129708] [<ffffffffa05dc838>] scrub_pending_bio_dec+0x38/0x70 [btrfs] [ 1929.143370] [<ffffffffa05dd0e0>] scrub_parity_bio_endio+0x50/0x70 [btrfs] [ 1929.157191] [<ffffffff812fa603>] bio_endio+0x53/0xa0 [ 1929.167382] [<ffffffffa05f96bc>] rbio_orig_end_io+0x7c/0xa0 [btrfs] [ 1929.180161] [<ffffffffa05f97ba>] raid_write_parity_end_io+0x5a/0x80 [btrfs] [ 1929.194318] [<ffffffff812fa603>] bio_endio+0x53/0xa0 [ 1929.204496] [<ffffffff8130401b>] blk_update_request+0x1eb/0x450 [ 1929.216569] [<ffffffff81096e58>] ? trigger_load_balance+0x78/0x500 [ 1929.229176] [<ffffffff8144c74d>] scsi_end_request+0x3d/0x1f0 [ 1929.240740] [<ffffffff8144ccac>] scsi_io_completion+0xac/0x5b0 [ 1929.252654] [<ffffffff81441c50>] scsi_finish_command+0xf0/0x150 [ 1929.264725] [<ffffffff8144d317>] scsi_softirq_done+0x147/0x170 [ 1929.276635] [<ffffffff8130ace6>] blk_done_softirq+0x86/0xa0 [ 1929.288014] [<ffffffff8105d92e>] __do_softirq+0xde/0x600 [ 1929.298885] [<ffffffff8105df6d>] irq_exit+0xbd/0xd0 (...) Fix this by using a reference count on the scrub context structure instead of locking the scrub_lock mutex. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-02-10 05:14:24 +08:00
scrub_put_ctx(sctx);
}
static void __scrub_blocked_if_needed(struct btrfs_fs_info *fs_info)
{
while (atomic_read(&fs_info->scrub_pause_req)) {
mutex_unlock(&fs_info->scrub_lock);
wait_event(fs_info->scrub_pause_wait,
atomic_read(&fs_info->scrub_pause_req) == 0);
mutex_lock(&fs_info->scrub_lock);
}
}
static void scrub_pause_on(struct btrfs_fs_info *fs_info)
{
atomic_inc(&fs_info->scrubs_paused);
wake_up(&fs_info->scrub_pause_wait);
}
static void scrub_pause_off(struct btrfs_fs_info *fs_info)
{
mutex_lock(&fs_info->scrub_lock);
__scrub_blocked_if_needed(fs_info);
atomic_dec(&fs_info->scrubs_paused);
mutex_unlock(&fs_info->scrub_lock);
wake_up(&fs_info->scrub_pause_wait);
}
static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info)
{
scrub_pause_on(fs_info);
scrub_pause_off(fs_info);
}
/*
* Insert new full stripe lock into full stripe locks tree
*
* Return pointer to existing or newly inserted full_stripe_lock structure if
* everything works well.
* Return ERR_PTR(-ENOMEM) if we failed to allocate memory
*
* NOTE: caller must hold full_stripe_locks_root->lock before calling this
* function
*/
static struct full_stripe_lock *insert_full_stripe_lock(
struct btrfs_full_stripe_locks_tree *locks_root,
u64 fstripe_logical)
{
struct rb_node **p;
struct rb_node *parent = NULL;
struct full_stripe_lock *entry;
struct full_stripe_lock *ret;
lockdep_assert_held(&locks_root->lock);
p = &locks_root->root.rb_node;
while (*p) {
parent = *p;
entry = rb_entry(parent, struct full_stripe_lock, node);
if (fstripe_logical < entry->logical) {
p = &(*p)->rb_left;
} else if (fstripe_logical > entry->logical) {
p = &(*p)->rb_right;
} else {
entry->refs++;
return entry;
}
}
/*
* Insert new lock.
*/
ret = kmalloc(sizeof(*ret), GFP_KERNEL);
if (!ret)
return ERR_PTR(-ENOMEM);
ret->logical = fstripe_logical;
ret->refs = 1;
mutex_init(&ret->mutex);
rb_link_node(&ret->node, parent, p);
rb_insert_color(&ret->node, &locks_root->root);
return ret;
}
/*
* Search for a full stripe lock of a block group
*
* Return pointer to existing full stripe lock if found
* Return NULL if not found
*/
static struct full_stripe_lock *search_full_stripe_lock(
struct btrfs_full_stripe_locks_tree *locks_root,
u64 fstripe_logical)
{
struct rb_node *node;
struct full_stripe_lock *entry;
lockdep_assert_held(&locks_root->lock);
node = locks_root->root.rb_node;
while (node) {
entry = rb_entry(node, struct full_stripe_lock, node);
if (fstripe_logical < entry->logical)
node = node->rb_left;
else if (fstripe_logical > entry->logical)
node = node->rb_right;
else
return entry;
}
return NULL;
}
/*
* Helper to get full stripe logical from a normal bytenr.
*
* Caller must ensure @cache is a RAID56 block group.
*/
static u64 get_full_stripe_logical(struct btrfs_block_group *cache, u64 bytenr)
{
u64 ret;
/*
* Due to chunk item size limit, full stripe length should not be
* larger than U32_MAX. Just a sanity check here.
*/
WARN_ON_ONCE(cache->full_stripe_len >= U32_MAX);
/*
* round_down() can only handle power of 2, while RAID56 full
* stripe length can be 64KiB * n, so we need to manually round down.
*/
ret = div64_u64(bytenr - cache->start, cache->full_stripe_len) *
cache->full_stripe_len + cache->start;
return ret;
}
/*
* Lock a full stripe to avoid concurrency of recovery and read
*
* It's only used for profiles with parities (RAID5/6), for other profiles it
* does nothing.
*
* Return 0 if we locked full stripe covering @bytenr, with a mutex held.
* So caller must call unlock_full_stripe() at the same context.
*
* Return <0 if encounters error.
*/
static int lock_full_stripe(struct btrfs_fs_info *fs_info, u64 bytenr,
bool *locked_ret)
{
struct btrfs_block_group *bg_cache;
struct btrfs_full_stripe_locks_tree *locks_root;
struct full_stripe_lock *existing;
u64 fstripe_start;
int ret = 0;
*locked_ret = false;
bg_cache = btrfs_lookup_block_group(fs_info, bytenr);
if (!bg_cache) {
ASSERT(0);
return -ENOENT;
}
/* Profiles not based on parity don't need full stripe lock */
if (!(bg_cache->flags & BTRFS_BLOCK_GROUP_RAID56_MASK))
goto out;
locks_root = &bg_cache->full_stripe_locks_root;
fstripe_start = get_full_stripe_logical(bg_cache, bytenr);
/* Now insert the full stripe lock */
mutex_lock(&locks_root->lock);
existing = insert_full_stripe_lock(locks_root, fstripe_start);
mutex_unlock(&locks_root->lock);
if (IS_ERR(existing)) {
ret = PTR_ERR(existing);
goto out;
}
mutex_lock(&existing->mutex);
*locked_ret = true;
out:
btrfs_put_block_group(bg_cache);
return ret;
}
/*
* Unlock a full stripe.
*
* NOTE: Caller must ensure it's the same context calling corresponding
* lock_full_stripe().
*
* Return 0 if we unlock full stripe without problem.
* Return <0 for error
*/
static int unlock_full_stripe(struct btrfs_fs_info *fs_info, u64 bytenr,
bool locked)
{
struct btrfs_block_group *bg_cache;
struct btrfs_full_stripe_locks_tree *locks_root;
struct full_stripe_lock *fstripe_lock;
u64 fstripe_start;
bool freeit = false;
int ret = 0;
/* If we didn't acquire full stripe lock, no need to continue */
if (!locked)
return 0;
bg_cache = btrfs_lookup_block_group(fs_info, bytenr);
if (!bg_cache) {
ASSERT(0);
return -ENOENT;
}
if (!(bg_cache->flags & BTRFS_BLOCK_GROUP_RAID56_MASK))
goto out;
locks_root = &bg_cache->full_stripe_locks_root;
fstripe_start = get_full_stripe_logical(bg_cache, bytenr);
mutex_lock(&locks_root->lock);
fstripe_lock = search_full_stripe_lock(locks_root, fstripe_start);
/* Unpaired unlock_full_stripe() detected */
if (!fstripe_lock) {
WARN_ON(1);
ret = -ENOENT;
mutex_unlock(&locks_root->lock);
goto out;
}
if (fstripe_lock->refs == 0) {
WARN_ON(1);
btrfs_warn(fs_info, "full stripe lock at %llu refcount underflow",
fstripe_lock->logical);
} else {
fstripe_lock->refs--;
}
if (fstripe_lock->refs == 0) {
rb_erase(&fstripe_lock->node, &locks_root->root);
freeit = true;
}
mutex_unlock(&locks_root->lock);
mutex_unlock(&fstripe_lock->mutex);
if (freeit)
kfree(fstripe_lock);
out:
btrfs_put_block_group(bg_cache);
return ret;
}
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
static void scrub_free_csums(struct scrub_ctx *sctx)
{
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
while (!list_empty(&sctx->csum_list)) {
struct btrfs_ordered_sum *sum;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
sum = list_first_entry(&sctx->csum_list,
struct btrfs_ordered_sum, list);
list_del(&sum->list);
kfree(sum);
}
}
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
static noinline_for_stack void scrub_free_ctx(struct scrub_ctx *sctx)
{
int i;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
if (!sctx)
return;
/* this can happen when scrub is cancelled */
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
if (sctx->curr != -1) {
struct scrub_bio *sbio = sctx->bios[sctx->curr];
for (i = 0; i < sbio->page_count; i++) {
WARN_ON(!sbio->pagev[i]->page);
scrub_block_put(sbio->pagev[i]->sblock);
}
bio_put(sbio->bio);
}
for (i = 0; i < SCRUB_BIOS_PER_SCTX; ++i) {
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
struct scrub_bio *sbio = sctx->bios[i];
if (!sbio)
break;
kfree(sbio);
}
kfree(sctx->wr_curr_bio);
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
scrub_free_csums(sctx);
kfree(sctx);
}
Btrfs: scrub, fix sleep in atomic context My previous patch "Btrfs: fix scrub race leading to use-after-free" introduced the possibility to sleep in an atomic context, which happens when the scrub_lock mutex is held at the time scrub_pending_bio_dec() is called - this function can be called under an atomic context. Chris ran into this in a debug kernel which gave the following trace: [ 1928.950319] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:621 [ 1928.967334] in_atomic(): 1, irqs_disabled(): 0, pid: 149670, name: fsstress [ 1928.981324] INFO: lockdep is turned off. [ 1928.989244] CPU: 24 PID: 149670 Comm: fsstress Tainted: G W 3.19.0-rc7-mason+ #41 [ 1929.006418] Hardware name: ZTSYSTEMS Echo Ridge T4 /A9DRPF-10D, BIOS 1.07 05/10/2012 [ 1929.022207] ffffffff81a22cf8 ffff881076e03b78 ffffffff816b8dd9 ffff881076e03b78 [ 1929.037267] ffff880d8e828710 ffff881076e03ba8 ffffffff810856c4 ffff881076e03bc8 [ 1929.052315] 0000000000000000 000000000000026d ffffffff81a22cf8 ffff881076e03bd8 [ 1929.067381] Call Trace: [ 1929.072344] <IRQ> [<ffffffff816b8dd9>] dump_stack+0x4f/0x6e [ 1929.083968] [<ffffffff810856c4>] ___might_sleep+0x174/0x230 [ 1929.095352] [<ffffffff810857d2>] __might_sleep+0x52/0x90 [ 1929.106223] [<ffffffff816bb68f>] mutex_lock_nested+0x2f/0x3b0 [ 1929.117951] [<ffffffff810ab37d>] ? trace_hardirqs_on+0xd/0x10 [ 1929.129708] [<ffffffffa05dc838>] scrub_pending_bio_dec+0x38/0x70 [btrfs] [ 1929.143370] [<ffffffffa05dd0e0>] scrub_parity_bio_endio+0x50/0x70 [btrfs] [ 1929.157191] [<ffffffff812fa603>] bio_endio+0x53/0xa0 [ 1929.167382] [<ffffffffa05f96bc>] rbio_orig_end_io+0x7c/0xa0 [btrfs] [ 1929.180161] [<ffffffffa05f97ba>] raid_write_parity_end_io+0x5a/0x80 [btrfs] [ 1929.194318] [<ffffffff812fa603>] bio_endio+0x53/0xa0 [ 1929.204496] [<ffffffff8130401b>] blk_update_request+0x1eb/0x450 [ 1929.216569] [<ffffffff81096e58>] ? trigger_load_balance+0x78/0x500 [ 1929.229176] [<ffffffff8144c74d>] scsi_end_request+0x3d/0x1f0 [ 1929.240740] [<ffffffff8144ccac>] scsi_io_completion+0xac/0x5b0 [ 1929.252654] [<ffffffff81441c50>] scsi_finish_command+0xf0/0x150 [ 1929.264725] [<ffffffff8144d317>] scsi_softirq_done+0x147/0x170 [ 1929.276635] [<ffffffff8130ace6>] blk_done_softirq+0x86/0xa0 [ 1929.288014] [<ffffffff8105d92e>] __do_softirq+0xde/0x600 [ 1929.298885] [<ffffffff8105df6d>] irq_exit+0xbd/0xd0 (...) Fix this by using a reference count on the scrub context structure instead of locking the scrub_lock mutex. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-02-10 05:14:24 +08:00
static void scrub_put_ctx(struct scrub_ctx *sctx)
{
if (refcount_dec_and_test(&sctx->refs))
Btrfs: scrub, fix sleep in atomic context My previous patch "Btrfs: fix scrub race leading to use-after-free" introduced the possibility to sleep in an atomic context, which happens when the scrub_lock mutex is held at the time scrub_pending_bio_dec() is called - this function can be called under an atomic context. Chris ran into this in a debug kernel which gave the following trace: [ 1928.950319] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:621 [ 1928.967334] in_atomic(): 1, irqs_disabled(): 0, pid: 149670, name: fsstress [ 1928.981324] INFO: lockdep is turned off. [ 1928.989244] CPU: 24 PID: 149670 Comm: fsstress Tainted: G W 3.19.0-rc7-mason+ #41 [ 1929.006418] Hardware name: ZTSYSTEMS Echo Ridge T4 /A9DRPF-10D, BIOS 1.07 05/10/2012 [ 1929.022207] ffffffff81a22cf8 ffff881076e03b78 ffffffff816b8dd9 ffff881076e03b78 [ 1929.037267] ffff880d8e828710 ffff881076e03ba8 ffffffff810856c4 ffff881076e03bc8 [ 1929.052315] 0000000000000000 000000000000026d ffffffff81a22cf8 ffff881076e03bd8 [ 1929.067381] Call Trace: [ 1929.072344] <IRQ> [<ffffffff816b8dd9>] dump_stack+0x4f/0x6e [ 1929.083968] [<ffffffff810856c4>] ___might_sleep+0x174/0x230 [ 1929.095352] [<ffffffff810857d2>] __might_sleep+0x52/0x90 [ 1929.106223] [<ffffffff816bb68f>] mutex_lock_nested+0x2f/0x3b0 [ 1929.117951] [<ffffffff810ab37d>] ? trace_hardirqs_on+0xd/0x10 [ 1929.129708] [<ffffffffa05dc838>] scrub_pending_bio_dec+0x38/0x70 [btrfs] [ 1929.143370] [<ffffffffa05dd0e0>] scrub_parity_bio_endio+0x50/0x70 [btrfs] [ 1929.157191] [<ffffffff812fa603>] bio_endio+0x53/0xa0 [ 1929.167382] [<ffffffffa05f96bc>] rbio_orig_end_io+0x7c/0xa0 [btrfs] [ 1929.180161] [<ffffffffa05f97ba>] raid_write_parity_end_io+0x5a/0x80 [btrfs] [ 1929.194318] [<ffffffff812fa603>] bio_endio+0x53/0xa0 [ 1929.204496] [<ffffffff8130401b>] blk_update_request+0x1eb/0x450 [ 1929.216569] [<ffffffff81096e58>] ? trigger_load_balance+0x78/0x500 [ 1929.229176] [<ffffffff8144c74d>] scsi_end_request+0x3d/0x1f0 [ 1929.240740] [<ffffffff8144ccac>] scsi_io_completion+0xac/0x5b0 [ 1929.252654] [<ffffffff81441c50>] scsi_finish_command+0xf0/0x150 [ 1929.264725] [<ffffffff8144d317>] scsi_softirq_done+0x147/0x170 [ 1929.276635] [<ffffffff8130ace6>] blk_done_softirq+0x86/0xa0 [ 1929.288014] [<ffffffff8105d92e>] __do_softirq+0xde/0x600 [ 1929.298885] [<ffffffff8105df6d>] irq_exit+0xbd/0xd0 (...) Fix this by using a reference count on the scrub context structure instead of locking the scrub_lock mutex. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-02-10 05:14:24 +08:00
scrub_free_ctx(sctx);
}
static noinline_for_stack struct scrub_ctx *scrub_setup_ctx(
struct btrfs_fs_info *fs_info, int is_dev_replace)
{
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
struct scrub_ctx *sctx;
int i;
sctx = kzalloc(sizeof(*sctx), GFP_KERNEL);
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
if (!sctx)
goto nomem;
refcount_set(&sctx->refs, 1);
sctx->is_dev_replace = is_dev_replace;
sctx->pages_per_rd_bio = SCRUB_PAGES_PER_RD_BIO;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
sctx->curr = -1;
sctx->fs_info = fs_info;
INIT_LIST_HEAD(&sctx->csum_list);
for (i = 0; i < SCRUB_BIOS_PER_SCTX; ++i) {
struct scrub_bio *sbio;
sbio = kzalloc(sizeof(*sbio), GFP_KERNEL);
if (!sbio)
goto nomem;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
sctx->bios[i] = sbio;
sbio->index = i;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
sbio->sctx = sctx;
sbio->page_count = 0;
btrfs_init_work(&sbio->work, scrub_bio_end_io_worker, NULL,
NULL);
if (i != SCRUB_BIOS_PER_SCTX - 1)
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
sctx->bios[i]->next_free = i + 1;
else
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
sctx->bios[i]->next_free = -1;
}
sctx->first_free = 0;
atomic_set(&sctx->bios_in_flight, 0);
atomic_set(&sctx->workers_pending, 0);
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
atomic_set(&sctx->cancel_req, 0);
spin_lock_init(&sctx->list_lock);
spin_lock_init(&sctx->stat_lock);
init_waitqueue_head(&sctx->list_wait);
WARN_ON(sctx->wr_curr_bio != NULL);
mutex_init(&sctx->wr_lock);
sctx->wr_curr_bio = NULL;
if (is_dev_replace) {
WARN_ON(!fs_info->dev_replace.tgtdev);
sctx->pages_per_wr_bio = SCRUB_PAGES_PER_WR_BIO;
sctx->wr_tgtdev = fs_info->dev_replace.tgtdev;
sctx->flush_all_writes = false;
}
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
return sctx;
nomem:
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
scrub_free_ctx(sctx);
return ERR_PTR(-ENOMEM);
}
static int scrub_print_warning_inode(u64 inum, u64 offset, u64 root,
void *warn_ctx)
{
u64 isize;
u32 nlink;
int ret;
int i;
unsigned nofs_flag;
struct extent_buffer *eb;
struct btrfs_inode_item *inode_item;
struct scrub_warning *swarn = warn_ctx;
struct btrfs_fs_info *fs_info = swarn->dev->fs_info;
struct inode_fs_paths *ipath = NULL;
struct btrfs_root *local_root;
struct btrfs_key key;
local_root = btrfs_get_fs_root(fs_info, root, true);
if (IS_ERR(local_root)) {
ret = PTR_ERR(local_root);
goto err;
}
/*
* this makes the path point to (inum INODE_ITEM ioff)
*/
key.objectid = inum;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
ret = btrfs_search_slot(NULL, local_root, &key, swarn->path, 0, 0);
if (ret) {
btrfs_put_root(local_root);
btrfs_release_path(swarn->path);
goto err;
}
eb = swarn->path->nodes[0];
inode_item = btrfs_item_ptr(eb, swarn->path->slots[0],
struct btrfs_inode_item);
isize = btrfs_inode_size(eb, inode_item);
nlink = btrfs_inode_nlink(eb, inode_item);
btrfs_release_path(swarn->path);
/*
* init_path might indirectly call vmalloc, or use GFP_KERNEL. Scrub
* uses GFP_NOFS in this context, so we keep it consistent but it does
* not seem to be strictly necessary.
*/
nofs_flag = memalloc_nofs_save();
ipath = init_ipath(4096, local_root, swarn->path);
memalloc_nofs_restore(nofs_flag);
if (IS_ERR(ipath)) {
btrfs_put_root(local_root);
ret = PTR_ERR(ipath);
ipath = NULL;
goto err;
}
ret = paths_from_inode(inum, ipath);
if (ret < 0)
goto err;
/*
* we deliberately ignore the bit ipath might have been too small to
* hold all of the paths here
*/
for (i = 0; i < ipath->fspath->elem_cnt; ++i)
btrfs_warn_in_rcu(fs_info,
"%s at logical %llu on dev %s, physical %llu, root %llu, inode %llu, offset %llu, length %llu, links %u (path: %s)",
swarn->errstr, swarn->logical,
rcu_str_deref(swarn->dev->name),
swarn->physical,
root, inum, offset,
min(isize - offset, (u64)PAGE_SIZE), nlink,
(char *)(unsigned long)ipath->fspath->val[i]);
btrfs_put_root(local_root);
free_ipath(ipath);
return 0;
err:
btrfs_warn_in_rcu(fs_info,
"%s at logical %llu on dev %s, physical %llu, root %llu, inode %llu, offset %llu: path resolving failed with ret=%d",
swarn->errstr, swarn->logical,
rcu_str_deref(swarn->dev->name),
swarn->physical,
root, inum, offset, ret);
free_ipath(ipath);
return 0;
}
static void scrub_print_warning(const char *errstr, struct scrub_block *sblock)
{
struct btrfs_device *dev;
struct btrfs_fs_info *fs_info;
struct btrfs_path *path;
struct btrfs_key found_key;
struct extent_buffer *eb;
struct btrfs_extent_item *ei;
struct scrub_warning swarn;
unsigned long ptr = 0;
u64 extent_item_pos;
u64 flags = 0;
u64 ref_root;
u32 item_size;
u8 ref_level = 0;
int ret;
WARN_ON(sblock->page_count < 1);
dev = sblock->pagev[0]->dev;
fs_info = sblock->sctx->fs_info;
path = btrfs_alloc_path();
if (!path)
return;
swarn.physical = sblock->pagev[0]->physical;
swarn.logical = sblock->pagev[0]->logical;
swarn.errstr = errstr;
swarn.dev = NULL;
ret = extent_from_logical(fs_info, swarn.logical, path, &found_key,
&flags);
if (ret < 0)
goto out;
extent_item_pos = swarn.logical - found_key.objectid;
swarn.extent_item_size = found_key.offset;
eb = path->nodes[0];
ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
item_size = btrfs_item_size_nr(eb, path->slots[0]);
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
do {
ret = tree_backref_for_extent(&ptr, eb, &found_key, ei,
item_size, &ref_root,
&ref_level);
btrfs_warn_in_rcu(fs_info,
"%s at logical %llu on dev %s, physical %llu: metadata %s (level %d) in tree %llu",
errstr, swarn.logical,
rcu_str_deref(dev->name),
swarn.physical,
ref_level ? "node" : "leaf",
ret < 0 ? -1 : ref_level,
ret < 0 ? -1 : ref_root);
} while (ret != 1);
btrfs_release_path(path);
} else {
btrfs_release_path(path);
swarn.path = path;
swarn.dev = dev;
iterate_extent_inodes(fs_info, found_key.objectid,
extent_item_pos, 1,
btrfs: add a flag to iterate_inodes_from_logical to find all extent refs for uncompressed extents The LOGICAL_INO ioctl provides a backward mapping from extent bytenr and offset (encoded as a single logical address) to a list of extent refs. LOGICAL_INO complements TREE_SEARCH, which provides the forward mapping (extent ref -> extent bytenr and offset, or logical address). These are useful capabilities for programs that manipulate extents and extent references from userspace (e.g. dedup and defrag utilities). When the extents are uncompressed (and not encrypted and not other), check_extent_in_eb performs filtering of the extent refs to remove any extent refs which do not contain the same extent offset as the 'logical' parameter's extent offset. This prevents LOGICAL_INO from returning references to more than a single block. To find the set of extent references to an uncompressed extent from [a, b), userspace has to run a loop like this pseudocode: for (i = a; i < b; ++i) extent_ref_set += LOGICAL_INO(i); At each iteration of the loop (up to 32768 iterations for a 128M extent), data we are interested in is collected in the kernel, then deleted by the filter in check_extent_in_eb. When the extents are compressed (or encrypted or other), the 'logical' parameter must be an extent bytenr (the 'a' parameter in the loop). No filtering by extent offset is done (or possible?) so the result is the complete set of extent refs for the entire extent. This removes the need for the loop, since we get all the extent refs in one call. Add an 'ignore_offset' argument to iterate_inodes_from_logical, [...several levels of function call graph...], and check_extent_in_eb, so that we can disable the extent offset filtering for uncompressed extents. This flag can be set by an improved version of the LOGICAL_INO ioctl to get either behavior as desired. There is no functional change in this patch. The new flag is always false. Signed-off-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org> Reviewed-by: David Sterba <dsterba@suse.com> [ minor coding style fixes ] Signed-off-by: David Sterba <dsterba@suse.com>
2017-09-23 01:58:45 +08:00
scrub_print_warning_inode, &swarn, false);
}
out:
btrfs_free_path(path);
}
static inline void scrub_get_recover(struct scrub_recover *recover)
{
refcount_inc(&recover->refs);
}
static inline void scrub_put_recover(struct btrfs_fs_info *fs_info,
struct scrub_recover *recover)
{
if (refcount_dec_and_test(&recover->refs)) {
btrfs_bio_counter_dec(fs_info);
btrfs_put_bbio(recover->bbio);
kfree(recover);
}
}
/*
* scrub_handle_errored_block gets called when either verification of the
* pages failed or the bio failed to read, e.g. with EIO. In the latter
* case, this function handles all pages in the bio, even though only one
* may be bad.
* The goal of this function is to repair the errored block by using the
* contents of one of the mirrors.
*/
static int scrub_handle_errored_block(struct scrub_block *sblock_to_check)
{
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
struct scrub_ctx *sctx = sblock_to_check->sctx;
struct btrfs_device *dev;
struct btrfs_fs_info *fs_info;
u64 logical;
unsigned int failed_mirror_index;
unsigned int is_metadata;
unsigned int have_csum;
struct scrub_block *sblocks_for_recheck; /* holds one for each mirror */
struct scrub_block *sblock_bad;
int ret;
int mirror_index;
int page_num;
int success;
btrfs: scrub: Fix RAID56 recovery race condition When scrubbing a RAID5 which has recoverable data corruption (only one data stripe is corrupted), sometimes scrub will report more csum errors than expected. Sometimes even unrecoverable error will be reported. The problem can be easily reproduced by the following steps: 1) Create a btrfs with RAID5 data profile with 3 devs 2) Mount it with nospace_cache or space_cache=v2 To avoid extra data space usage. 3) Create a 128K file and sync the fs, unmount it Now the 128K file lies at the beginning of the data chunk 4) Locate the physical bytenr of data chunk on dev3 Dev3 is the 1st data stripe. 5) Corrupt the first 64K of the data chunk stripe on dev3 6) Mount the fs and scrub it The correct csum error number should be 16 (assuming using x86_64). Larger csum error number can be reported in a 1/3 chance. And unrecoverable error can also be reported in a 1/10 chance. The root cause of the problem is RAID5/6 recover code has race condition, due to the fact that full scrub is initiated per device. While for other mirror based profiles, each mirror is independent with each other, so race won't cause any big problem. For example: Corrupted | Correct | Correct | | Scrub dev3 (D1) | Scrub dev2 (D2) | Scrub dev1(P) | ------------------------------------------------------------------------ Read out D1 |Read out D2 |Read full stripe | Check csum |Check csum |Check parity | Csum mismatch |Csum match, continue |Parity mismatch | handle_errored_block | |handle_errored_block | Read out full stripe | | Read out full stripe| D1 csum error(err++) | | D1 csum error(err++)| Recover D1 | | Recover D1 | So D1's csum error is accounted twice, just because handle_errored_block() doesn't have enough protection, and race can happen. On even worse case, for example D1's recovery code is re-writing D1/D2/P, and P's recovery code is just reading out full stripe, then we can cause unrecoverable error. This patch will use previously introduced lock_full_stripe() and unlock_full_stripe() to protect the whole scrub_handle_errored_block() function for RAID56 recovery. So no extra csum error nor unrecoverable error. Reported-by: Goffredo Baroncelli <kreijack@libero.it> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-04-14 08:35:55 +08:00
bool full_stripe_locked;
unsigned int nofs_flag;
static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL,
DEFAULT_RATELIMIT_BURST);
BUG_ON(sblock_to_check->page_count < 1);
fs_info = sctx->fs_info;
if (sblock_to_check->pagev[0]->flags & BTRFS_EXTENT_FLAG_SUPER) {
/*
* if we find an error in a super block, we just report it.
* They will get written with the next transaction commit
* anyway
*/
spin_lock(&sctx->stat_lock);
++sctx->stat.super_errors;
spin_unlock(&sctx->stat_lock);
return 0;
}
logical = sblock_to_check->pagev[0]->logical;
BUG_ON(sblock_to_check->pagev[0]->mirror_num < 1);
failed_mirror_index = sblock_to_check->pagev[0]->mirror_num - 1;
is_metadata = !(sblock_to_check->pagev[0]->flags &
BTRFS_EXTENT_FLAG_DATA);
have_csum = sblock_to_check->pagev[0]->have_csum;
dev = sblock_to_check->pagev[0]->dev;
btrfs: zoned: relocate block group to repair IO failure in zoned filesystems When a bad checksum is found and if the filesystem has a mirror of the damaged data, we read the correct data from the mirror and writes it to damaged blocks. This however, violates the sequential write constraints of a zoned block device. We can consider three methods to repair an IO failure in zoned filesystems: (1) Reset and rewrite the damaged zone (2) Allocate new device extent and replace the damaged device extent to the new extent (3) Relocate the corresponding block group Method (1) is most similar to a behavior done with regular devices. However, it also wipes non-damaged data in the same device extent, and so it unnecessary degrades non-damaged data. Method (2) is much like device replacing but done in the same device. It is safe because it keeps the device extent until the replacing finish. However, extending device replacing is non-trivial. It assumes "src_dev->physical == dst_dev->physical". Also, the extent mapping replacing function should be extended to support replacing device extent position in one device. Method (3) invokes relocation of the damaged block group and is straightforward to implement. It relocates all the mirrored device extents, so it potentially is a more costly operation than method (1) or (2). But it relocates only used extents which reduce the total IO size. Let's apply method (3) for now. In the future, we can extend device-replace and apply method (2). For protecting a block group gets relocated multiple time with multiple IO errors, this commit introduces "relocating_repair" bit to show it's now relocating to repair IO failures. Also it uses a new kthread "btrfs-relocating-repair", not to block IO path with relocating process. This commit also supports repairing in the scrub process. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-04 18:22:16 +08:00
if (btrfs_is_zoned(fs_info) && !sctx->is_dev_replace)
return btrfs_repair_one_zone(fs_info, logical);
/*
* We must use GFP_NOFS because the scrub task might be waiting for a
* worker task executing this function and in turn a transaction commit
* might be waiting the scrub task to pause (which needs to wait for all
* the worker tasks to complete before pausing).
* We do allocations in the workers through insert_full_stripe_lock()
* and scrub_add_page_to_wr_bio(), which happens down the call chain of
* this function.
*/
nofs_flag = memalloc_nofs_save();
btrfs: scrub: Fix RAID56 recovery race condition When scrubbing a RAID5 which has recoverable data corruption (only one data stripe is corrupted), sometimes scrub will report more csum errors than expected. Sometimes even unrecoverable error will be reported. The problem can be easily reproduced by the following steps: 1) Create a btrfs with RAID5 data profile with 3 devs 2) Mount it with nospace_cache or space_cache=v2 To avoid extra data space usage. 3) Create a 128K file and sync the fs, unmount it Now the 128K file lies at the beginning of the data chunk 4) Locate the physical bytenr of data chunk on dev3 Dev3 is the 1st data stripe. 5) Corrupt the first 64K of the data chunk stripe on dev3 6) Mount the fs and scrub it The correct csum error number should be 16 (assuming using x86_64). Larger csum error number can be reported in a 1/3 chance. And unrecoverable error can also be reported in a 1/10 chance. The root cause of the problem is RAID5/6 recover code has race condition, due to the fact that full scrub is initiated per device. While for other mirror based profiles, each mirror is independent with each other, so race won't cause any big problem. For example: Corrupted | Correct | Correct | | Scrub dev3 (D1) | Scrub dev2 (D2) | Scrub dev1(P) | ------------------------------------------------------------------------ Read out D1 |Read out D2 |Read full stripe | Check csum |Check csum |Check parity | Csum mismatch |Csum match, continue |Parity mismatch | handle_errored_block | |handle_errored_block | Read out full stripe | | Read out full stripe| D1 csum error(err++) | | D1 csum error(err++)| Recover D1 | | Recover D1 | So D1's csum error is accounted twice, just because handle_errored_block() doesn't have enough protection, and race can happen. On even worse case, for example D1's recovery code is re-writing D1/D2/P, and P's recovery code is just reading out full stripe, then we can cause unrecoverable error. This patch will use previously introduced lock_full_stripe() and unlock_full_stripe() to protect the whole scrub_handle_errored_block() function for RAID56 recovery. So no extra csum error nor unrecoverable error. Reported-by: Goffredo Baroncelli <kreijack@libero.it> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-04-14 08:35:55 +08:00
/*
* For RAID5/6, race can happen for a different device scrub thread.
* For data corruption, Parity and Data threads will both try
* to recovery the data.
* Race can lead to doubly added csum error, or even unrecoverable
* error.
*/
ret = lock_full_stripe(fs_info, logical, &full_stripe_locked);
if (ret < 0) {
memalloc_nofs_restore(nofs_flag);
btrfs: scrub: Fix RAID56 recovery race condition When scrubbing a RAID5 which has recoverable data corruption (only one data stripe is corrupted), sometimes scrub will report more csum errors than expected. Sometimes even unrecoverable error will be reported. The problem can be easily reproduced by the following steps: 1) Create a btrfs with RAID5 data profile with 3 devs 2) Mount it with nospace_cache or space_cache=v2 To avoid extra data space usage. 3) Create a 128K file and sync the fs, unmount it Now the 128K file lies at the beginning of the data chunk 4) Locate the physical bytenr of data chunk on dev3 Dev3 is the 1st data stripe. 5) Corrupt the first 64K of the data chunk stripe on dev3 6) Mount the fs and scrub it The correct csum error number should be 16 (assuming using x86_64). Larger csum error number can be reported in a 1/3 chance. And unrecoverable error can also be reported in a 1/10 chance. The root cause of the problem is RAID5/6 recover code has race condition, due to the fact that full scrub is initiated per device. While for other mirror based profiles, each mirror is independent with each other, so race won't cause any big problem. For example: Corrupted | Correct | Correct | | Scrub dev3 (D1) | Scrub dev2 (D2) | Scrub dev1(P) | ------------------------------------------------------------------------ Read out D1 |Read out D2 |Read full stripe | Check csum |Check csum |Check parity | Csum mismatch |Csum match, continue |Parity mismatch | handle_errored_block | |handle_errored_block | Read out full stripe | | Read out full stripe| D1 csum error(err++) | | D1 csum error(err++)| Recover D1 | | Recover D1 | So D1's csum error is accounted twice, just because handle_errored_block() doesn't have enough protection, and race can happen. On even worse case, for example D1's recovery code is re-writing D1/D2/P, and P's recovery code is just reading out full stripe, then we can cause unrecoverable error. This patch will use previously introduced lock_full_stripe() and unlock_full_stripe() to protect the whole scrub_handle_errored_block() function for RAID56 recovery. So no extra csum error nor unrecoverable error. Reported-by: Goffredo Baroncelli <kreijack@libero.it> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-04-14 08:35:55 +08:00
spin_lock(&sctx->stat_lock);
if (ret == -ENOMEM)
sctx->stat.malloc_errors++;
sctx->stat.read_errors++;
sctx->stat.uncorrectable_errors++;
spin_unlock(&sctx->stat_lock);
return ret;
}
/*
* read all mirrors one after the other. This includes to
* re-read the extent or metadata block that failed (that was
* the cause that this fixup code is called) another time,
* page by page this time in order to know which pages
* caused I/O errors and which ones are good (for all mirrors).
* It is the goal to handle the situation when more than one
* mirror contains I/O errors, but the errors do not
* overlap, i.e. the data can be repaired by selecting the
* pages from those mirrors without I/O error on the
* particular pages. One example (with blocks >= 2 * PAGE_SIZE)
* would be that mirror #1 has an I/O error on the first page,
* the second page is good, and mirror #2 has an I/O error on
* the second page, but the first page is good.
* Then the first page of the first mirror can be repaired by
* taking the first page of the second mirror, and the
* second page of the second mirror can be repaired by
* copying the contents of the 2nd page of the 1st mirror.
* One more note: if the pages of one mirror contain I/O
* errors, the checksum cannot be verified. In order to get
* the best data for repairing, the first attempt is to find
* a mirror without I/O errors and with a validated checksum.
* Only if this is not possible, the pages are picked from
* mirrors with I/O errors without considering the checksum.
* If the latter is the case, at the end, the checksum of the
* repaired area is verified in order to correctly maintain
* the statistics.
*/
sblocks_for_recheck = kcalloc(BTRFS_MAX_MIRRORS,
sizeof(*sblocks_for_recheck), GFP_KERNEL);
if (!sblocks_for_recheck) {
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
spin_lock(&sctx->stat_lock);
sctx->stat.malloc_errors++;
sctx->stat.read_errors++;
sctx->stat.uncorrectable_errors++;
spin_unlock(&sctx->stat_lock);
btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
goto out;
}
/* setup the context, map the logical blocks and alloc the pages */
ret = scrub_setup_recheck_block(sblock_to_check, sblocks_for_recheck);
if (ret) {
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
spin_lock(&sctx->stat_lock);
sctx->stat.read_errors++;
sctx->stat.uncorrectable_errors++;
spin_unlock(&sctx->stat_lock);
btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
goto out;
}
BUG_ON(failed_mirror_index >= BTRFS_MAX_MIRRORS);
sblock_bad = sblocks_for_recheck + failed_mirror_index;
/* build and submit the bios for the failed mirror, check checksums */
scrub_recheck_block(fs_info, sblock_bad, 1);
if (!sblock_bad->header_error && !sblock_bad->checksum_error &&
sblock_bad->no_io_error_seen) {
/*
* the error disappeared after reading page by page, or
* the area was part of a huge bio and other parts of the
* bio caused I/O errors, or the block layer merged several
* read requests into one and the error is caused by a
* different bio (usually one of the two latter cases is
* the cause)
*/
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
spin_lock(&sctx->stat_lock);
sctx->stat.unverified_errors++;
2014-11-06 17:20:58 +08:00
sblock_to_check->data_corrected = 1;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
spin_unlock(&sctx->stat_lock);
if (sctx->is_dev_replace)
scrub_write_block_to_dev_replace(sblock_bad);
goto out;
}
if (!sblock_bad->no_io_error_seen) {
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
spin_lock(&sctx->stat_lock);
sctx->stat.read_errors++;
spin_unlock(&sctx->stat_lock);
if (__ratelimit(&rs))
scrub_print_warning("i/o error", sblock_to_check);
btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
} else if (sblock_bad->checksum_error) {
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
spin_lock(&sctx->stat_lock);
sctx->stat.csum_errors++;
spin_unlock(&sctx->stat_lock);
if (__ratelimit(&rs))
scrub_print_warning("checksum error", sblock_to_check);
btrfs_dev_stat_inc_and_print(dev,
BTRFS_DEV_STAT_CORRUPTION_ERRS);
} else if (sblock_bad->header_error) {
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
spin_lock(&sctx->stat_lock);
sctx->stat.verify_errors++;
spin_unlock(&sctx->stat_lock);
if (__ratelimit(&rs))
scrub_print_warning("checksum/header error",
sblock_to_check);
if (sblock_bad->generation_error)
btrfs_dev_stat_inc_and_print(dev,
BTRFS_DEV_STAT_GENERATION_ERRS);
else
btrfs_dev_stat_inc_and_print(dev,
BTRFS_DEV_STAT_CORRUPTION_ERRS);
}
if (sctx->readonly) {
ASSERT(!sctx->is_dev_replace);
goto out;
}
/*
* now build and submit the bios for the other mirrors, check
* checksums.
* First try to pick the mirror which is completely without I/O
* errors and also does not have a checksum error.
* If one is found, and if a checksum is present, the full block
* that is known to contain an error is rewritten. Afterwards
* the block is known to be corrected.
* If a mirror is found which is completely correct, and no
* checksum is present, only those pages are rewritten that had
* an I/O error in the block to be repaired, since it cannot be
* determined, which copy of the other pages is better (and it
* could happen otherwise that a correct page would be
* overwritten by a bad one).
*/
for (mirror_index = 0; ;mirror_index++) {
struct scrub_block *sblock_other;
if (mirror_index == failed_mirror_index)
continue;
/* raid56's mirror can be more than BTRFS_MAX_MIRRORS */
if (!scrub_is_page_on_raid56(sblock_bad->pagev[0])) {
if (mirror_index >= BTRFS_MAX_MIRRORS)
break;
if (!sblocks_for_recheck[mirror_index].page_count)
break;
sblock_other = sblocks_for_recheck + mirror_index;
} else {
struct scrub_recover *r = sblock_bad->pagev[0]->recover;
int max_allowed = r->bbio->num_stripes -
r->bbio->num_tgtdevs;
if (mirror_index >= max_allowed)
break;
if (!sblocks_for_recheck[1].page_count)
break;
ASSERT(failed_mirror_index == 0);
sblock_other = sblocks_for_recheck + 1;
sblock_other->pagev[0]->mirror_num = 1 + mirror_index;
}
/* build and submit the bios, check checksums */
scrub_recheck_block(fs_info, sblock_other, 0);
if (!sblock_other->header_error &&
!sblock_other->checksum_error &&
sblock_other->no_io_error_seen) {
if (sctx->is_dev_replace) {
scrub_write_block_to_dev_replace(sblock_other);
goto corrected_error;
} else {
ret = scrub_repair_block_from_good_copy(
sblock_bad, sblock_other);
if (!ret)
goto corrected_error;
}
}
}
if (sblock_bad->no_io_error_seen && !sctx->is_dev_replace)
goto did_not_correct_error;
/*
* In case of I/O errors in the area that is supposed to be
* repaired, continue by picking good copies of those pages.
* Select the good pages from mirrors to rewrite bad pages from
* the area to fix. Afterwards verify the checksum of the block
* that is supposed to be repaired. This verification step is
* only done for the purpose of statistic counting and for the
* final scrub report, whether errors remain.
* A perfect algorithm could make use of the checksum and try
* all possible combinations of pages from the different mirrors
* until the checksum verification succeeds. For example, when
* the 2nd page of mirror #1 faces I/O errors, and the 2nd page
* of mirror #2 is readable but the final checksum test fails,
* then the 2nd page of mirror #3 could be tried, whether now
* the final checksum succeeds. But this would be a rare
* exception and is therefore not implemented. At least it is
* avoided that the good copy is overwritten.
* A more useful improvement would be to pick the sectors
* without I/O error based on sector sizes (512 bytes on legacy
* disks) instead of on PAGE_SIZE. Then maybe 512 byte of one
* mirror could be repaired by taking 512 byte of a different
* mirror, even if other 512 byte sectors in the same PAGE_SIZE
* area are unreadable.
*/
success = 1;
for (page_num = 0; page_num < sblock_bad->page_count;
page_num++) {
struct scrub_page *spage_bad = sblock_bad->pagev[page_num];
struct scrub_block *sblock_other = NULL;
/* skip no-io-error page in scrub */
if (!spage_bad->io_error && !sctx->is_dev_replace)
continue;
if (scrub_is_page_on_raid56(sblock_bad->pagev[0])) {
/*
* In case of dev replace, if raid56 rebuild process
* didn't work out correct data, then copy the content
* in sblock_bad to make sure target device is identical
* to source device, instead of writing garbage data in
* sblock_for_recheck array to target device.
*/
sblock_other = NULL;
} else if (spage_bad->io_error) {
/* try to find no-io-error page in mirrors */
for (mirror_index = 0;
mirror_index < BTRFS_MAX_MIRRORS &&
sblocks_for_recheck[mirror_index].page_count > 0;
mirror_index++) {
if (!sblocks_for_recheck[mirror_index].
pagev[page_num]->io_error) {
sblock_other = sblocks_for_recheck +
mirror_index;
break;
}
}
if (!sblock_other)
success = 0;
}
if (sctx->is_dev_replace) {
/*
* did not find a mirror to fetch the page
* from. scrub_write_page_to_dev_replace()
* handles this case (page->io_error), by
* filling the block with zeros before
* submitting the write request
*/
if (!sblock_other)
sblock_other = sblock_bad;
if (scrub_write_page_to_dev_replace(sblock_other,
page_num) != 0) {
atomic64_inc(
&fs_info->dev_replace.num_write_errors);
success = 0;
}
} else if (sblock_other) {
ret = scrub_repair_page_from_good_copy(sblock_bad,
sblock_other,
page_num, 0);
if (0 == ret)
spage_bad->io_error = 0;
else
success = 0;
}
}
if (success && !sctx->is_dev_replace) {
if (is_metadata || have_csum) {
/*
* need to verify the checksum now that all
* sectors on disk are repaired (the write
* request for data to be repaired is on its way).
* Just be lazy and use scrub_recheck_block()
* which re-reads the data before the checksum
* is verified, but most likely the data comes out
* of the page cache.
*/
scrub_recheck_block(fs_info, sblock_bad, 1);
if (!sblock_bad->header_error &&
!sblock_bad->checksum_error &&
sblock_bad->no_io_error_seen)
goto corrected_error;
else
goto did_not_correct_error;
} else {
corrected_error:
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
spin_lock(&sctx->stat_lock);
sctx->stat.corrected_errors++;
2014-11-06 17:20:58 +08:00
sblock_to_check->data_corrected = 1;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
spin_unlock(&sctx->stat_lock);
btrfs_err_rl_in_rcu(fs_info,
"fixed up error at logical %llu on dev %s",
logical, rcu_str_deref(dev->name));
}
} else {
did_not_correct_error:
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
spin_lock(&sctx->stat_lock);
sctx->stat.uncorrectable_errors++;
spin_unlock(&sctx->stat_lock);
btrfs_err_rl_in_rcu(fs_info,
"unable to fixup (regular) error at logical %llu on dev %s",
logical, rcu_str_deref(dev->name));
}
out:
if (sblocks_for_recheck) {
for (mirror_index = 0; mirror_index < BTRFS_MAX_MIRRORS;
mirror_index++) {
struct scrub_block *sblock = sblocks_for_recheck +
mirror_index;
struct scrub_recover *recover;
int page_index;
for (page_index = 0; page_index < sblock->page_count;
page_index++) {
sblock->pagev[page_index]->sblock = NULL;
recover = sblock->pagev[page_index]->recover;
if (recover) {
scrub_put_recover(fs_info, recover);
sblock->pagev[page_index]->recover =
NULL;
}
scrub_page_put(sblock->pagev[page_index]);
}
}
kfree(sblocks_for_recheck);
}
btrfs: scrub: Fix RAID56 recovery race condition When scrubbing a RAID5 which has recoverable data corruption (only one data stripe is corrupted), sometimes scrub will report more csum errors than expected. Sometimes even unrecoverable error will be reported. The problem can be easily reproduced by the following steps: 1) Create a btrfs with RAID5 data profile with 3 devs 2) Mount it with nospace_cache or space_cache=v2 To avoid extra data space usage. 3) Create a 128K file and sync the fs, unmount it Now the 128K file lies at the beginning of the data chunk 4) Locate the physical bytenr of data chunk on dev3 Dev3 is the 1st data stripe. 5) Corrupt the first 64K of the data chunk stripe on dev3 6) Mount the fs and scrub it The correct csum error number should be 16 (assuming using x86_64). Larger csum error number can be reported in a 1/3 chance. And unrecoverable error can also be reported in a 1/10 chance. The root cause of the problem is RAID5/6 recover code has race condition, due to the fact that full scrub is initiated per device. While for other mirror based profiles, each mirror is independent with each other, so race won't cause any big problem. For example: Corrupted | Correct | Correct | | Scrub dev3 (D1) | Scrub dev2 (D2) | Scrub dev1(P) | ------------------------------------------------------------------------ Read out D1 |Read out D2 |Read full stripe | Check csum |Check csum |Check parity | Csum mismatch |Csum match, continue |Parity mismatch | handle_errored_block | |handle_errored_block | Read out full stripe | | Read out full stripe| D1 csum error(err++) | | D1 csum error(err++)| Recover D1 | | Recover D1 | So D1's csum error is accounted twice, just because handle_errored_block() doesn't have enough protection, and race can happen. On even worse case, for example D1's recovery code is re-writing D1/D2/P, and P's recovery code is just reading out full stripe, then we can cause unrecoverable error. This patch will use previously introduced lock_full_stripe() and unlock_full_stripe() to protect the whole scrub_handle_errored_block() function for RAID56 recovery. So no extra csum error nor unrecoverable error. Reported-by: Goffredo Baroncelli <kreijack@libero.it> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-04-14 08:35:55 +08:00
ret = unlock_full_stripe(fs_info, logical, full_stripe_locked);
memalloc_nofs_restore(nofs_flag);
btrfs: scrub: Fix RAID56 recovery race condition When scrubbing a RAID5 which has recoverable data corruption (only one data stripe is corrupted), sometimes scrub will report more csum errors than expected. Sometimes even unrecoverable error will be reported. The problem can be easily reproduced by the following steps: 1) Create a btrfs with RAID5 data profile with 3 devs 2) Mount it with nospace_cache or space_cache=v2 To avoid extra data space usage. 3) Create a 128K file and sync the fs, unmount it Now the 128K file lies at the beginning of the data chunk 4) Locate the physical bytenr of data chunk on dev3 Dev3 is the 1st data stripe. 5) Corrupt the first 64K of the data chunk stripe on dev3 6) Mount the fs and scrub it The correct csum error number should be 16 (assuming using x86_64). Larger csum error number can be reported in a 1/3 chance. And unrecoverable error can also be reported in a 1/10 chance. The root cause of the problem is RAID5/6 recover code has race condition, due to the fact that full scrub is initiated per device. While for other mirror based profiles, each mirror is independent with each other, so race won't cause any big problem. For example: Corrupted | Correct | Correct | | Scrub dev3 (D1) | Scrub dev2 (D2) | Scrub dev1(P) | ------------------------------------------------------------------------ Read out D1 |Read out D2 |Read full stripe | Check csum |Check csum |Check parity | Csum mismatch |Csum match, continue |Parity mismatch | handle_errored_block | |handle_errored_block | Read out full stripe | | Read out full stripe| D1 csum error(err++) | | D1 csum error(err++)| Recover D1 | | Recover D1 | So D1's csum error is accounted twice, just because handle_errored_block() doesn't have enough protection, and race can happen. On even worse case, for example D1's recovery code is re-writing D1/D2/P, and P's recovery code is just reading out full stripe, then we can cause unrecoverable error. This patch will use previously introduced lock_full_stripe() and unlock_full_stripe() to protect the whole scrub_handle_errored_block() function for RAID56 recovery. So no extra csum error nor unrecoverable error. Reported-by: Goffredo Baroncelli <kreijack@libero.it> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-04-14 08:35:55 +08:00
if (ret < 0)
return ret;
return 0;
}
static inline int scrub_nr_raid_mirrors(struct btrfs_bio *bbio)
{
if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID5)
return 2;
else if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID6)
return 3;
else
return (int)bbio->num_stripes;
}
static inline void scrub_stripe_index_and_offset(u64 logical, u64 map_type,
u64 *raid_map,
u64 mapped_length,
int nstripes, int mirror,
int *stripe_index,
u64 *stripe_offset)
{
int i;
if (map_type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
/* RAID5/6 */
for (i = 0; i < nstripes; i++) {
if (raid_map[i] == RAID6_Q_STRIPE ||
raid_map[i] == RAID5_P_STRIPE)
continue;
if (logical >= raid_map[i] &&
logical < raid_map[i] + mapped_length)
break;
}
*stripe_index = i;
*stripe_offset = logical - raid_map[i];
} else {
/* The other RAID type */
*stripe_index = mirror;
*stripe_offset = 0;
}
}
static int scrub_setup_recheck_block(struct scrub_block *original_sblock,
struct scrub_block *sblocks_for_recheck)
{
struct scrub_ctx *sctx = original_sblock->sctx;
struct btrfs_fs_info *fs_info = sctx->fs_info;
u64 length = original_sblock->page_count * PAGE_SIZE;
u64 logical = original_sblock->pagev[0]->logical;
u64 generation = original_sblock->pagev[0]->generation;
u64 flags = original_sblock->pagev[0]->flags;
u64 have_csum = original_sblock->pagev[0]->have_csum;
struct scrub_recover *recover;
struct btrfs_bio *bbio;
u64 sublen;
u64 mapped_length;
u64 stripe_offset;
int stripe_index;
int page_index = 0;
int mirror_index;
int nmirrors;
int ret;
/*
* note: the two members refs and outstanding_pages
* are not used (and not set) in the blocks that are used for
* the recheck procedure
*/
while (length > 0) {
sublen = min_t(u64, length, PAGE_SIZE);
mapped_length = sublen;
bbio = NULL;
/*
* with a length of PAGE_SIZE, each returned stripe
* represents one mirror
*/
btrfs_bio_counter_inc_blocked(fs_info);
ret = btrfs_map_sblock(fs_info, BTRFS_MAP_GET_READ_MIRRORS,
logical, &mapped_length, &bbio);
if (ret || !bbio || mapped_length < sublen) {
btrfs_put_bbio(bbio);
btrfs_bio_counter_dec(fs_info);
return -EIO;
}
recover = kzalloc(sizeof(struct scrub_recover), GFP_NOFS);
if (!recover) {
btrfs_put_bbio(bbio);
btrfs_bio_counter_dec(fs_info);
return -ENOMEM;
}
refcount_set(&recover->refs, 1);
recover->bbio = bbio;
recover->map_length = mapped_length;
BUG_ON(page_index >= SCRUB_MAX_PAGES_PER_BLOCK);
nmirrors = min(scrub_nr_raid_mirrors(bbio), BTRFS_MAX_MIRRORS);
for (mirror_index = 0; mirror_index < nmirrors;
mirror_index++) {
struct scrub_block *sblock;
struct scrub_page *spage;
sblock = sblocks_for_recheck + mirror_index;
sblock->sctx = sctx;
spage = kzalloc(sizeof(*spage), GFP_NOFS);
if (!spage) {
leave_nomem:
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
spin_lock(&sctx->stat_lock);
sctx->stat.malloc_errors++;
spin_unlock(&sctx->stat_lock);
scrub_put_recover(fs_info, recover);
return -ENOMEM;
}
scrub_page_get(spage);
sblock->pagev[page_index] = spage;
spage->sblock = sblock;
spage->flags = flags;
spage->generation = generation;
spage->logical = logical;
spage->have_csum = have_csum;
if (have_csum)
memcpy(spage->csum,
original_sblock->pagev[0]->csum,
sctx->fs_info->csum_size);
scrub_stripe_index_and_offset(logical,
bbio->map_type,
bbio->raid_map,
mapped_length,
bbio->num_stripes -
bbio->num_tgtdevs,
mirror_index,
&stripe_index,
&stripe_offset);
spage->physical = bbio->stripes[stripe_index].physical +
stripe_offset;
spage->dev = bbio->stripes[stripe_index].dev;
BUG_ON(page_index >= original_sblock->page_count);
spage->physical_for_dev_replace =
original_sblock->pagev[page_index]->
physical_for_dev_replace;
/* for missing devices, dev->bdev is NULL */
spage->mirror_num = mirror_index + 1;
sblock->page_count++;
spage->page = alloc_page(GFP_NOFS);
if (!spage->page)
goto leave_nomem;
scrub_get_recover(recover);
spage->recover = recover;
}
scrub_put_recover(fs_info, recover);
length -= sublen;
logical += sublen;
page_index++;
}
return 0;
}
static void scrub_bio_wait_endio(struct bio *bio)
{
complete(bio->bi_private);
}
static int scrub_submit_raid56_bio_wait(struct btrfs_fs_info *fs_info,
struct bio *bio,
struct scrub_page *spage)
{
DECLARE_COMPLETION_ONSTACK(done);
int ret;
int mirror_num;
bio->bi_iter.bi_sector = spage->logical >> 9;
bio->bi_private = &done;
bio->bi_end_io = scrub_bio_wait_endio;
mirror_num = spage->sblock->pagev[0]->mirror_num;
ret = raid56_parity_recover(fs_info, bio, spage->recover->bbio,
spage->recover->map_length,
mirror_num, 0);
if (ret)
return ret;
wait_for_completion_io(&done);
return blk_status_to_errno(bio->bi_status);
}
static void scrub_recheck_block_on_raid56(struct btrfs_fs_info *fs_info,
struct scrub_block *sblock)
{
struct scrub_page *first_page = sblock->pagev[0];
struct bio *bio;
int page_num;
/* All pages in sblock belong to the same stripe on the same device. */
ASSERT(first_page->dev);
if (!first_page->dev->bdev)
goto out;
bio = btrfs_io_bio_alloc(BIO_MAX_VECS);
bio_set_dev(bio, first_page->dev->bdev);
for (page_num = 0; page_num < sblock->page_count; page_num++) {
struct scrub_page *spage = sblock->pagev[page_num];
WARN_ON(!spage->page);
bio_add_page(bio, spage->page, PAGE_SIZE, 0);
}
if (scrub_submit_raid56_bio_wait(fs_info, bio, first_page)) {
bio_put(bio);
goto out;
}
bio_put(bio);
scrub_recheck_block_checksum(sblock);
return;
out:
for (page_num = 0; page_num < sblock->page_count; page_num++)
sblock->pagev[page_num]->io_error = 1;
sblock->no_io_error_seen = 0;
}
/*
* this function will check the on disk data for checksum errors, header
* errors and read I/O errors. If any I/O errors happen, the exact pages
* which are errored are marked as being bad. The goal is to enable scrub
* to take those pages that are not errored from all the mirrors so that
* the pages that are errored in the just handled mirror can be repaired.
*/
static void scrub_recheck_block(struct btrfs_fs_info *fs_info,
struct scrub_block *sblock,
int retry_failed_mirror)
{
int page_num;
sblock->no_io_error_seen = 1;
/* short cut for raid56 */
if (!retry_failed_mirror && scrub_is_page_on_raid56(sblock->pagev[0]))
return scrub_recheck_block_on_raid56(fs_info, sblock);
for (page_num = 0; page_num < sblock->page_count; page_num++) {
struct bio *bio;
struct scrub_page *spage = sblock->pagev[page_num];
if (spage->dev->bdev == NULL) {
spage->io_error = 1;
sblock->no_io_error_seen = 0;
continue;
}
WARN_ON(!spage->page);
bio = btrfs_io_bio_alloc(1);
bio_set_dev(bio, spage->dev->bdev);
bio_add_page(bio, spage->page, PAGE_SIZE, 0);
bio->bi_iter.bi_sector = spage->physical >> 9;
bio->bi_opf = REQ_OP_READ;
if (btrfsic_submit_bio_wait(bio)) {
spage->io_error = 1;
sblock->no_io_error_seen = 0;
}
bio_put(bio);
}
if (sblock->no_io_error_seen)
scrub_recheck_block_checksum(sblock);
}
static inline int scrub_check_fsid(u8 fsid[],
struct scrub_page *spage)
{
struct btrfs_fs_devices *fs_devices = spage->dev->fs_devices;
int ret;
ret = memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
return !ret;
}
static void scrub_recheck_block_checksum(struct scrub_block *sblock)
{
sblock->header_error = 0;
sblock->checksum_error = 0;
sblock->generation_error = 0;
if (sblock->pagev[0]->flags & BTRFS_EXTENT_FLAG_DATA)
scrub_checksum_data(sblock);
else
scrub_checksum_tree_block(sblock);
}
static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad,
struct scrub_block *sblock_good)
{
int page_num;
int ret = 0;
for (page_num = 0; page_num < sblock_bad->page_count; page_num++) {
int ret_sub;
ret_sub = scrub_repair_page_from_good_copy(sblock_bad,
sblock_good,
page_num, 1);
if (ret_sub)
ret = ret_sub;
}
return ret;
}
static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
struct scrub_block *sblock_good,
int page_num, int force_write)
{
struct scrub_page *spage_bad = sblock_bad->pagev[page_num];
struct scrub_page *spage_good = sblock_good->pagev[page_num];
struct btrfs_fs_info *fs_info = sblock_bad->sctx->fs_info;
BUG_ON(spage_bad->page == NULL);
BUG_ON(spage_good->page == NULL);
if (force_write || sblock_bad->header_error ||
sblock_bad->checksum_error || spage_bad->io_error) {
struct bio *bio;
int ret;
if (!spage_bad->dev->bdev) {
btrfs_warn_rl(fs_info,
"scrub_repair_page_from_good_copy(bdev == NULL) is unexpected");
return -EIO;
}
bio = btrfs_io_bio_alloc(1);
bio_set_dev(bio, spage_bad->dev->bdev);
bio->bi_iter.bi_sector = spage_bad->physical >> 9;
bio->bi_opf = REQ_OP_WRITE;
ret = bio_add_page(bio, spage_good->page, PAGE_SIZE, 0);
if (PAGE_SIZE != ret) {
bio_put(bio);
return -EIO;
}
if (btrfsic_submit_bio_wait(bio)) {
btrfs_dev_stat_inc_and_print(spage_bad->dev,
BTRFS_DEV_STAT_WRITE_ERRS);
atomic64_inc(&fs_info->dev_replace.num_write_errors);
bio_put(bio);
return -EIO;
}
bio_put(bio);
}
return 0;
}
static void scrub_write_block_to_dev_replace(struct scrub_block *sblock)
{
struct btrfs_fs_info *fs_info = sblock->sctx->fs_info;
int page_num;
2014-11-06 17:20:58 +08:00
/*
* This block is used for the check of the parity on the source device,
* so the data needn't be written into the destination device.
*/
if (sblock->sparity)
return;
for (page_num = 0; page_num < sblock->page_count; page_num++) {
int ret;
ret = scrub_write_page_to_dev_replace(sblock, page_num);
if (ret)
atomic64_inc(&fs_info->dev_replace.num_write_errors);
}
}
static int scrub_write_page_to_dev_replace(struct scrub_block *sblock,
int page_num)
{
struct scrub_page *spage = sblock->pagev[page_num];
BUG_ON(spage->page == NULL);
if (spage->io_error)
clear_page(page_address(spage->page));
return scrub_add_page_to_wr_bio(sblock->sctx, spage);
}
static int fill_writer_pointer_gap(struct scrub_ctx *sctx, u64 physical)
{
int ret = 0;
u64 length;
if (!btrfs_is_zoned(sctx->fs_info))
return 0;
if (!btrfs_dev_is_sequential(sctx->wr_tgtdev, physical))
return 0;
if (sctx->write_pointer < physical) {
length = physical - sctx->write_pointer;
ret = btrfs_zoned_issue_zeroout(sctx->wr_tgtdev,
sctx->write_pointer, length);
if (!ret)
sctx->write_pointer = physical;
}
return ret;
}
static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx,
struct scrub_page *spage)
{
struct scrub_bio *sbio;
int ret;
mutex_lock(&sctx->wr_lock);
again:
if (!sctx->wr_curr_bio) {
sctx->wr_curr_bio = kzalloc(sizeof(*sctx->wr_curr_bio),
GFP_KERNEL);
if (!sctx->wr_curr_bio) {
mutex_unlock(&sctx->wr_lock);
return -ENOMEM;
}
sctx->wr_curr_bio->sctx = sctx;
sctx->wr_curr_bio->page_count = 0;
}
sbio = sctx->wr_curr_bio;
if (sbio->page_count == 0) {
struct bio *bio;
ret = fill_writer_pointer_gap(sctx,
spage->physical_for_dev_replace);
if (ret) {
mutex_unlock(&sctx->wr_lock);
return ret;
}
sbio->physical = spage->physical_for_dev_replace;
sbio->logical = spage->logical;
sbio->dev = sctx->wr_tgtdev;
bio = sbio->bio;
if (!bio) {
bio = btrfs_io_bio_alloc(sctx->pages_per_wr_bio);
sbio->bio = bio;
}
bio->bi_private = sbio;
bio->bi_end_io = scrub_wr_bio_end_io;
bio_set_dev(bio, sbio->dev->bdev);
block: Abstract out bvec iterator Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-10-12 06:44:27 +08:00
bio->bi_iter.bi_sector = sbio->physical >> 9;
bio->bi_opf = REQ_OP_WRITE;
sbio->status = 0;
} else if (sbio->physical + sbio->page_count * PAGE_SIZE !=
spage->physical_for_dev_replace ||
sbio->logical + sbio->page_count * PAGE_SIZE !=
spage->logical) {
scrub_wr_submit(sctx);
goto again;
}
ret = bio_add_page(sbio->bio, spage->page, PAGE_SIZE, 0);
if (ret != PAGE_SIZE) {
if (sbio->page_count < 1) {
bio_put(sbio->bio);
sbio->bio = NULL;
mutex_unlock(&sctx->wr_lock);
return -EIO;
}
scrub_wr_submit(sctx);
goto again;
}
sbio->pagev[sbio->page_count] = spage;
scrub_page_get(spage);
sbio->page_count++;
if (sbio->page_count == sctx->pages_per_wr_bio)
scrub_wr_submit(sctx);
mutex_unlock(&sctx->wr_lock);
return 0;
}
static void scrub_wr_submit(struct scrub_ctx *sctx)
{
struct scrub_bio *sbio;
if (!sctx->wr_curr_bio)
return;
sbio = sctx->wr_curr_bio;
sctx->wr_curr_bio = NULL;
WARN_ON(!sbio->bio->bi_bdev);
scrub_pending_bio_inc(sctx);
/* process all writes in a single worker thread. Then the block layer
* orders the requests before sending them to the driver which
* doubled the write performance on spinning disks when measured
* with Linux 3.5 */
btrfsic_submit_bio(sbio->bio);
if (btrfs_is_zoned(sctx->fs_info))
sctx->write_pointer = sbio->physical + sbio->page_count * PAGE_SIZE;
}
static void scrub_wr_bio_end_io(struct bio *bio)
{
struct scrub_bio *sbio = bio->bi_private;
struct btrfs_fs_info *fs_info = sbio->dev->fs_info;
sbio->status = bio->bi_status;
sbio->bio = bio;
btrfs_init_work(&sbio->work, scrub_wr_bio_end_io_worker, NULL, NULL);
btrfs_queue_work(fs_info->scrub_wr_completion_workers, &sbio->work);
}
static void scrub_wr_bio_end_io_worker(struct btrfs_work *work)
{
struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
struct scrub_ctx *sctx = sbio->sctx;
int i;
WARN_ON(sbio->page_count > SCRUB_PAGES_PER_WR_BIO);
if (sbio->status) {
struct btrfs_dev_replace *dev_replace =
&sbio->sctx->fs_info->dev_replace;
for (i = 0; i < sbio->page_count; i++) {
struct scrub_page *spage = sbio->pagev[i];
spage->io_error = 1;
atomic64_inc(&dev_replace->num_write_errors);
}
}
for (i = 0; i < sbio->page_count; i++)
scrub_page_put(sbio->pagev[i]);
bio_put(sbio->bio);
kfree(sbio);
scrub_pending_bio_dec(sctx);
}
static int scrub_checksum(struct scrub_block *sblock)
{
u64 flags;
int ret;
/*
* No need to initialize these stats currently,
* because this function only use return value
* instead of these stats value.
*
* Todo:
* always use stats
*/
sblock->header_error = 0;
sblock->generation_error = 0;
sblock->checksum_error = 0;
WARN_ON(sblock->page_count < 1);
flags = sblock->pagev[0]->flags;
ret = 0;
if (flags & BTRFS_EXTENT_FLAG_DATA)
ret = scrub_checksum_data(sblock);
else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
ret = scrub_checksum_tree_block(sblock);
else if (flags & BTRFS_EXTENT_FLAG_SUPER)
(void)scrub_checksum_super(sblock);
else
WARN_ON(1);
if (ret)
scrub_handle_errored_block(sblock);
return ret;
}
static int scrub_checksum_data(struct scrub_block *sblock)
{
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
struct scrub_ctx *sctx = sblock->sctx;
struct btrfs_fs_info *fs_info = sctx->fs_info;
SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
u8 csum[BTRFS_CSUM_SIZE];
struct scrub_page *spage;
char *kaddr;
BUG_ON(sblock->page_count < 1);
spage = sblock->pagev[0];
if (!spage->have_csum)
return 0;
kaddr = page_address(spage->page);
shash->tfm = fs_info->csum_shash;
crypto_shash_init(shash);
/*
* In scrub_pages() and scrub_pages_for_parity() we ensure each spage
* only contains one sector of data.
*/
crypto_shash_digest(shash, kaddr, fs_info->sectorsize, csum);
if (memcmp(csum, spage->csum, fs_info->csum_size))
sblock->checksum_error = 1;
return sblock->checksum_error;
}
static int scrub_checksum_tree_block(struct scrub_block *sblock)
{
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
struct scrub_ctx *sctx = sblock->sctx;
struct btrfs_header *h;
struct btrfs_fs_info *fs_info = sctx->fs_info;
SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
u8 calculated_csum[BTRFS_CSUM_SIZE];
u8 on_disk_csum[BTRFS_CSUM_SIZE];
/*
* This is done in sectorsize steps even for metadata as there's a
* constraint for nodesize to be aligned to sectorsize. This will need
* to change so we don't misuse data and metadata units like that.
*/
const u32 sectorsize = sctx->fs_info->sectorsize;
const int num_sectors = fs_info->nodesize >> fs_info->sectorsize_bits;
int i;
struct scrub_page *spage;
char *kaddr;
BUG_ON(sblock->page_count < 1);
/* Each member in pagev is just one block, not a full page */
ASSERT(sblock->page_count == num_sectors);
spage = sblock->pagev[0];
kaddr = page_address(spage->page);
h = (struct btrfs_header *)kaddr;
memcpy(on_disk_csum, h->csum, sctx->fs_info->csum_size);
/*
* we don't use the getter functions here, as we
* a) don't have an extent buffer and
* b) the page is already kmapped
*/
if (spage->logical != btrfs_stack_header_bytenr(h))
sblock->header_error = 1;
if (spage->generation != btrfs_stack_header_generation(h)) {
sblock->header_error = 1;
sblock->generation_error = 1;
}
if (!scrub_check_fsid(h->fsid, spage))
sblock->header_error = 1;
if (memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
BTRFS_UUID_SIZE))
sblock->header_error = 1;
shash->tfm = fs_info->csum_shash;
crypto_shash_init(shash);
crypto_shash_update(shash, kaddr + BTRFS_CSUM_SIZE,
sectorsize - BTRFS_CSUM_SIZE);
for (i = 1; i < num_sectors; i++) {
kaddr = page_address(sblock->pagev[i]->page);
crypto_shash_update(shash, kaddr, sectorsize);
}
crypto_shash_final(shash, calculated_csum);
if (memcmp(calculated_csum, on_disk_csum, sctx->fs_info->csum_size))
sblock->checksum_error = 1;
return sblock->header_error || sblock->checksum_error;
}
static int scrub_checksum_super(struct scrub_block *sblock)
{
struct btrfs_super_block *s;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
struct scrub_ctx *sctx = sblock->sctx;
struct btrfs_fs_info *fs_info = sctx->fs_info;
SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
u8 calculated_csum[BTRFS_CSUM_SIZE];
struct scrub_page *spage;
char *kaddr;
int fail_gen = 0;
int fail_cor = 0;
BUG_ON(sblock->page_count < 1);
spage = sblock->pagev[0];
kaddr = page_address(spage->page);
s = (struct btrfs_super_block *)kaddr;
if (spage->logical != btrfs_super_bytenr(s))
++fail_cor;
if (spage->generation != btrfs_super_generation(s))
++fail_gen;
if (!scrub_check_fsid(s->fsid, spage))
++fail_cor;
shash->tfm = fs_info->csum_shash;
crypto_shash_init(shash);
crypto_shash_digest(shash, kaddr + BTRFS_CSUM_SIZE,
BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE, calculated_csum);
if (memcmp(calculated_csum, s->csum, sctx->fs_info->csum_size))
++fail_cor;
if (fail_cor + fail_gen) {
/*
* if we find an error in a super block, we just report it.
* They will get written with the next transaction commit
* anyway
*/
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
spin_lock(&sctx->stat_lock);
++sctx->stat.super_errors;
spin_unlock(&sctx->stat_lock);
if (fail_cor)
btrfs_dev_stat_inc_and_print(spage->dev,
BTRFS_DEV_STAT_CORRUPTION_ERRS);
else
btrfs_dev_stat_inc_and_print(spage->dev,
BTRFS_DEV_STAT_GENERATION_ERRS);
}
return fail_cor + fail_gen;
}
static void scrub_block_get(struct scrub_block *sblock)
{
refcount_inc(&sblock->refs);
}
static void scrub_block_put(struct scrub_block *sblock)
{
if (refcount_dec_and_test(&sblock->refs)) {
int i;
2014-11-06 17:20:58 +08:00
if (sblock->sparity)
scrub_parity_put(sblock->sparity);
for (i = 0; i < sblock->page_count; i++)
scrub_page_put(sblock->pagev[i]);
kfree(sblock);
}
}
static void scrub_page_get(struct scrub_page *spage)
{
atomic_inc(&spage->refs);
}
static void scrub_page_put(struct scrub_page *spage)
{
if (atomic_dec_and_test(&spage->refs)) {
if (spage->page)
__free_page(spage->page);
kfree(spage);
}
}
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
static void scrub_submit(struct scrub_ctx *sctx)
{
struct scrub_bio *sbio;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
if (sctx->curr == -1)
return;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
sbio = sctx->bios[sctx->curr];
sctx->curr = -1;
scrub_pending_bio_inc(sctx);
btrfsic_submit_bio(sbio->bio);
}
static int scrub_add_page_to_rd_bio(struct scrub_ctx *sctx,
struct scrub_page *spage)
{
struct scrub_block *sblock = spage->sblock;
struct scrub_bio *sbio;
int ret;
again:
/*
* grab a fresh bio or wait for one to become available
*/
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
while (sctx->curr == -1) {
spin_lock(&sctx->list_lock);
sctx->curr = sctx->first_free;
if (sctx->curr != -1) {
sctx->first_free = sctx->bios[sctx->curr]->next_free;
sctx->bios[sctx->curr]->next_free = -1;
sctx->bios[sctx->curr]->page_count = 0;
spin_unlock(&sctx->list_lock);
} else {
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
spin_unlock(&sctx->list_lock);
wait_event(sctx->list_wait, sctx->first_free != -1);
}
}
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
sbio = sctx->bios[sctx->curr];
if (sbio->page_count == 0) {
struct bio *bio;
sbio->physical = spage->physical;
sbio->logical = spage->logical;
sbio->dev = spage->dev;
bio = sbio->bio;
if (!bio) {
bio = btrfs_io_bio_alloc(sctx->pages_per_rd_bio);
sbio->bio = bio;
}
bio->bi_private = sbio;
bio->bi_end_io = scrub_bio_end_io;
bio_set_dev(bio, sbio->dev->bdev);
block: Abstract out bvec iterator Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-10-12 06:44:27 +08:00
bio->bi_iter.bi_sector = sbio->physical >> 9;
bio->bi_opf = REQ_OP_READ;
sbio->status = 0;
} else if (sbio->physical + sbio->page_count * PAGE_SIZE !=
spage->physical ||
sbio->logical + sbio->page_count * PAGE_SIZE !=
spage->logical ||
sbio->dev != spage->dev) {
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
scrub_submit(sctx);
goto again;
}
sbio->pagev[sbio->page_count] = spage;
ret = bio_add_page(sbio->bio, spage->page, PAGE_SIZE, 0);
if (ret != PAGE_SIZE) {
if (sbio->page_count < 1) {
bio_put(sbio->bio);
sbio->bio = NULL;
return -EIO;
}
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
scrub_submit(sctx);
goto again;
}
scrub_block_get(sblock); /* one for the page added to the bio */
atomic_inc(&sblock->outstanding_pages);
sbio->page_count++;
if (sbio->page_count == sctx->pages_per_rd_bio)
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
scrub_submit(sctx);
return 0;
}
Merge branch 'for-linus-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs Pull btrfs updates from Chris Mason: "This has Jeff Mahoney's long standing trim patch that fixes corners where trims were missing. Omar has some raid5/6 fixes, especially for using scrub and device replace when devices are missing. Zhao Lie continues cleaning and fixing things, this series fixes some really hard to hit corners in xfstests. I had to pull it last merge window due to some deadlocks, but those are now resolved. I added support for Tejun's new blkio controllers. It seems to work well for single devices, we'll expand to multi-device as well" * 'for-linus-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (47 commits) btrfs: fix compile when block cgroups are not enabled Btrfs: fix file read corruption after extent cloning and fsync Btrfs: check if previous transaction aborted to avoid fs corruption btrfs: use __GFP_NOFAIL in alloc_btrfs_bio btrfs: Prevent from early transaction abort btrfs: Remove unused arguments in tree-log.c btrfs: Remove useless condition in start_log_trans() Btrfs: add support for blkio controllers Btrfs: remove unused mutex from struct 'btrfs_fs_info' Btrfs: fix parity scrub of RAID 5/6 with missing device Btrfs: fix device replace of a missing RAID 5/6 device Btrfs: add RAID 5/6 BTRFS_RBIO_REBUILD_MISSING operation Btrfs: count devices correctly in readahead during RAID 5/6 replace Btrfs: remove misleading handling of missing device scrub btrfs: fix clone / extent-same deadlocks Btrfs: fix defrag to merge tail file extent Btrfs: fix warning in backref walking btrfs: Add WARN_ON() for double lock in btrfs_tree_lock() btrfs: Remove root argument in extent_data_ref_count() btrfs: Fix wrong comment of btrfs_alloc_tree_block() ...
2015-09-06 06:14:43 +08:00
static void scrub_missing_raid56_end_io(struct bio *bio)
{
struct scrub_block *sblock = bio->bi_private;
struct btrfs_fs_info *fs_info = sblock->sctx->fs_info;
if (bio->bi_status)
sblock->no_io_error_seen = 0;
bio_put(bio);
btrfs_queue_work(fs_info->scrub_workers, &sblock->work);
}
static void scrub_missing_raid56_worker(struct btrfs_work *work)
{
struct scrub_block *sblock = container_of(work, struct scrub_block, work);
struct scrub_ctx *sctx = sblock->sctx;
struct btrfs_fs_info *fs_info = sctx->fs_info;
u64 logical;
struct btrfs_device *dev;
logical = sblock->pagev[0]->logical;
dev = sblock->pagev[0]->dev;
if (sblock->no_io_error_seen)
scrub_recheck_block_checksum(sblock);
if (!sblock->no_io_error_seen) {
spin_lock(&sctx->stat_lock);
sctx->stat.read_errors++;
spin_unlock(&sctx->stat_lock);
btrfs_err_rl_in_rcu(fs_info,
"IO error rebuilding logical %llu for dev %s",
logical, rcu_str_deref(dev->name));
} else if (sblock->header_error || sblock->checksum_error) {
spin_lock(&sctx->stat_lock);
sctx->stat.uncorrectable_errors++;
spin_unlock(&sctx->stat_lock);
btrfs_err_rl_in_rcu(fs_info,
"failed to rebuild valid logical %llu for dev %s",
logical, rcu_str_deref(dev->name));
} else {
scrub_write_block_to_dev_replace(sblock);
}
if (sctx->is_dev_replace && sctx->flush_all_writes) {
mutex_lock(&sctx->wr_lock);
scrub_wr_submit(sctx);
mutex_unlock(&sctx->wr_lock);
}
scrub_block_put(sblock);
scrub_pending_bio_dec(sctx);
}
static void scrub_missing_raid56_pages(struct scrub_block *sblock)
{
struct scrub_ctx *sctx = sblock->sctx;
struct btrfs_fs_info *fs_info = sctx->fs_info;
u64 length = sblock->page_count * PAGE_SIZE;
u64 logical = sblock->pagev[0]->logical;
struct btrfs_bio *bbio = NULL;
struct bio *bio;
struct btrfs_raid_bio *rbio;
int ret;
int i;
btrfs: Wait for in-flight bios before freeing target device for raid56 When raid56 dev-replace is cancelled by running scrub, we will free target device without waiting for in-flight bios, causing the following NULL pointer deference or general protection failure. BUG: unable to handle kernel NULL pointer dereference at 00000000000005e0 IP: generic_make_request_checks+0x4d/0x610 CPU: 1 PID: 11676 Comm: kworker/u4:14 Tainted: G O 4.11.0-rc2 #72 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.2-20170228_101828-anatol 04/01/2014 Workqueue: btrfs-endio-raid56 btrfs_endio_raid56_helper [btrfs] task: ffff88002875b4c0 task.stack: ffffc90001334000 RIP: 0010:generic_make_request_checks+0x4d/0x610 Call Trace: ? generic_make_request+0xc7/0x360 generic_make_request+0x24/0x360 ? generic_make_request+0xc7/0x360 submit_bio+0x64/0x120 ? page_in_rbio+0x4d/0x80 [btrfs] ? rbio_orig_end_io+0x80/0x80 [btrfs] finish_rmw+0x3f4/0x540 [btrfs] validate_rbio_for_rmw+0x36/0x40 [btrfs] raid_rmw_end_io+0x7a/0x90 [btrfs] bio_endio+0x56/0x60 end_workqueue_fn+0x3c/0x40 [btrfs] btrfs_scrubparity_helper+0xef/0x620 [btrfs] btrfs_endio_raid56_helper+0xe/0x10 [btrfs] process_one_work+0x2af/0x720 ? process_one_work+0x22b/0x720 worker_thread+0x4b/0x4f0 kthread+0x10f/0x150 ? process_one_work+0x720/0x720 ? kthread_create_on_node+0x40/0x40 ret_from_fork+0x2e/0x40 RIP: generic_make_request_checks+0x4d/0x610 RSP: ffffc90001337bb8 In btrfs_dev_replace_finishing(), we will call btrfs_rm_dev_replace_blocked() to wait bios before destroying the target device when scrub is finished normally. However when dev-replace is aborted, either due to error or cancelled by scrub, we didn't wait for bios, this can lead to use-after-free if there are bios holding the target device. Furthermore, for raid56 scrub, at least 2 places are calling btrfs_map_sblock() without protection of bio_counter, leading to the problem. This patch fixes the problem: 1) Wait for bio_counter before freeing target device when canceling replace 2) When calling btrfs_map_sblock() for raid56, use bio_counter to protect the call. Cc: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-03-29 09:33:21 +08:00
btrfs_bio_counter_inc_blocked(fs_info);
ret = btrfs_map_sblock(fs_info, BTRFS_MAP_GET_READ_MIRRORS, logical,
&length, &bbio);
if (ret || !bbio || !bbio->raid_map)
goto bbio_out;
if (WARN_ON(!sctx->is_dev_replace ||
!(bbio->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK))) {
/*
* We shouldn't be scrubbing a missing device. Even for dev
* replace, we should only get here for RAID 5/6. We either
* managed to mount something with no mirrors remaining or
* there's a bug in scrub_remap_extent()/btrfs_map_block().
*/
goto bbio_out;
}
bio = btrfs_io_bio_alloc(0);
bio->bi_iter.bi_sector = logical >> 9;
bio->bi_private = sblock;
bio->bi_end_io = scrub_missing_raid56_end_io;
rbio = raid56_alloc_missing_rbio(fs_info, bio, bbio, length);
if (!rbio)
goto rbio_out;
for (i = 0; i < sblock->page_count; i++) {
struct scrub_page *spage = sblock->pagev[i];
raid56_add_scrub_pages(rbio, spage->page, spage->logical);
}
btrfs_init_work(&sblock->work, scrub_missing_raid56_worker, NULL, NULL);
scrub_block_get(sblock);
scrub_pending_bio_inc(sctx);
raid56_submit_missing_rbio(rbio);
return;
rbio_out:
bio_put(bio);
bbio_out:
btrfs: Wait for in-flight bios before freeing target device for raid56 When raid56 dev-replace is cancelled by running scrub, we will free target device without waiting for in-flight bios, causing the following NULL pointer deference or general protection failure. BUG: unable to handle kernel NULL pointer dereference at 00000000000005e0 IP: generic_make_request_checks+0x4d/0x610 CPU: 1 PID: 11676 Comm: kworker/u4:14 Tainted: G O 4.11.0-rc2 #72 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.2-20170228_101828-anatol 04/01/2014 Workqueue: btrfs-endio-raid56 btrfs_endio_raid56_helper [btrfs] task: ffff88002875b4c0 task.stack: ffffc90001334000 RIP: 0010:generic_make_request_checks+0x4d/0x610 Call Trace: ? generic_make_request+0xc7/0x360 generic_make_request+0x24/0x360 ? generic_make_request+0xc7/0x360 submit_bio+0x64/0x120 ? page_in_rbio+0x4d/0x80 [btrfs] ? rbio_orig_end_io+0x80/0x80 [btrfs] finish_rmw+0x3f4/0x540 [btrfs] validate_rbio_for_rmw+0x36/0x40 [btrfs] raid_rmw_end_io+0x7a/0x90 [btrfs] bio_endio+0x56/0x60 end_workqueue_fn+0x3c/0x40 [btrfs] btrfs_scrubparity_helper+0xef/0x620 [btrfs] btrfs_endio_raid56_helper+0xe/0x10 [btrfs] process_one_work+0x2af/0x720 ? process_one_work+0x22b/0x720 worker_thread+0x4b/0x4f0 kthread+0x10f/0x150 ? process_one_work+0x720/0x720 ? kthread_create_on_node+0x40/0x40 ret_from_fork+0x2e/0x40 RIP: generic_make_request_checks+0x4d/0x610 RSP: ffffc90001337bb8 In btrfs_dev_replace_finishing(), we will call btrfs_rm_dev_replace_blocked() to wait bios before destroying the target device when scrub is finished normally. However when dev-replace is aborted, either due to error or cancelled by scrub, we didn't wait for bios, this can lead to use-after-free if there are bios holding the target device. Furthermore, for raid56 scrub, at least 2 places are calling btrfs_map_sblock() without protection of bio_counter, leading to the problem. This patch fixes the problem: 1) Wait for bio_counter before freeing target device when canceling replace 2) When calling btrfs_map_sblock() for raid56, use bio_counter to protect the call. Cc: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-03-29 09:33:21 +08:00
btrfs_bio_counter_dec(fs_info);
btrfs_put_bbio(bbio);
spin_lock(&sctx->stat_lock);
sctx->stat.malloc_errors++;
spin_unlock(&sctx->stat_lock);
}
static int scrub_pages(struct scrub_ctx *sctx, u64 logical, u32 len,
u64 physical, struct btrfs_device *dev, u64 flags,
u64 gen, int mirror_num, u8 *csum,
u64 physical_for_dev_replace)
{
struct scrub_block *sblock;
const u32 sectorsize = sctx->fs_info->sectorsize;
int index;
sblock = kzalloc(sizeof(*sblock), GFP_KERNEL);
if (!sblock) {
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
spin_lock(&sctx->stat_lock);
sctx->stat.malloc_errors++;
spin_unlock(&sctx->stat_lock);
return -ENOMEM;
}
/* one ref inside this function, plus one for each page added to
* a bio later on */
refcount_set(&sblock->refs, 1);
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
sblock->sctx = sctx;
sblock->no_io_error_seen = 1;
for (index = 0; len > 0; index++) {
struct scrub_page *spage;
/*
* Here we will allocate one page for one sector to scrub.
* This is fine if PAGE_SIZE == sectorsize, but will cost
* more memory for PAGE_SIZE > sectorsize case.
*/
u32 l = min(sectorsize, len);
spage = kzalloc(sizeof(*spage), GFP_KERNEL);
if (!spage) {
leave_nomem:
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
spin_lock(&sctx->stat_lock);
sctx->stat.malloc_errors++;
spin_unlock(&sctx->stat_lock);
scrub_block_put(sblock);
return -ENOMEM;
}
BUG_ON(index >= SCRUB_MAX_PAGES_PER_BLOCK);
scrub_page_get(spage);
sblock->pagev[index] = spage;
spage->sblock = sblock;
spage->dev = dev;
spage->flags = flags;
spage->generation = gen;
spage->logical = logical;
spage->physical = physical;
spage->physical_for_dev_replace = physical_for_dev_replace;
spage->mirror_num = mirror_num;
if (csum) {
spage->have_csum = 1;
memcpy(spage->csum, csum, sctx->fs_info->csum_size);
} else {
spage->have_csum = 0;
}
sblock->page_count++;
spage->page = alloc_page(GFP_KERNEL);
if (!spage->page)
goto leave_nomem;
len -= l;
logical += l;
physical += l;
physical_for_dev_replace += l;
}
WARN_ON(sblock->page_count == 0);
if (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state)) {
/*
* This case should only be hit for RAID 5/6 device replace. See
* the comment in scrub_missing_raid56_pages() for details.
*/
scrub_missing_raid56_pages(sblock);
} else {
for (index = 0; index < sblock->page_count; index++) {
struct scrub_page *spage = sblock->pagev[index];
int ret;
ret = scrub_add_page_to_rd_bio(sctx, spage);
if (ret) {
scrub_block_put(sblock);
return ret;
}
}
if (flags & BTRFS_EXTENT_FLAG_SUPER)
scrub_submit(sctx);
}
/* last one frees, either here or in bio completion for last page */
scrub_block_put(sblock);
return 0;
}
static void scrub_bio_end_io(struct bio *bio)
{
struct scrub_bio *sbio = bio->bi_private;
struct btrfs_fs_info *fs_info = sbio->dev->fs_info;
sbio->status = bio->bi_status;
sbio->bio = bio;
btrfs_queue_work(fs_info->scrub_workers, &sbio->work);
}
static void scrub_bio_end_io_worker(struct btrfs_work *work)
{
struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
struct scrub_ctx *sctx = sbio->sctx;
int i;
BUG_ON(sbio->page_count > SCRUB_PAGES_PER_RD_BIO);
if (sbio->status) {
for (i = 0; i < sbio->page_count; i++) {
struct scrub_page *spage = sbio->pagev[i];
spage->io_error = 1;
spage->sblock->no_io_error_seen = 0;
}
}
/* now complete the scrub_block items that have all pages completed */
for (i = 0; i < sbio->page_count; i++) {
struct scrub_page *spage = sbio->pagev[i];
struct scrub_block *sblock = spage->sblock;
if (atomic_dec_and_test(&sblock->outstanding_pages))
scrub_block_complete(sblock);
scrub_block_put(sblock);
}
bio_put(sbio->bio);
sbio->bio = NULL;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
spin_lock(&sctx->list_lock);
sbio->next_free = sctx->first_free;
sctx->first_free = sbio->index;
spin_unlock(&sctx->list_lock);
if (sctx->is_dev_replace && sctx->flush_all_writes) {
mutex_lock(&sctx->wr_lock);
scrub_wr_submit(sctx);
mutex_unlock(&sctx->wr_lock);
}
scrub_pending_bio_dec(sctx);
}
2014-11-06 17:20:58 +08:00
static inline void __scrub_mark_bitmap(struct scrub_parity *sparity,
unsigned long *bitmap,
u64 start, u32 len)
2014-11-06 17:20:58 +08:00
{
u64 offset;
u32 nsectors;
u32 sectorsize_bits = sparity->sctx->fs_info->sectorsize_bits;
2014-11-06 17:20:58 +08:00
if (len >= sparity->stripe_len) {
bitmap_set(bitmap, 0, sparity->nsectors);
return;
}
start -= sparity->logic_start;
start = div64_u64_rem(start, sparity->stripe_len, &offset);
offset = offset >> sectorsize_bits;
nsectors = len >> sectorsize_bits;
2014-11-06 17:20:58 +08:00
if (offset + nsectors <= sparity->nsectors) {
bitmap_set(bitmap, offset, nsectors);
return;
}
bitmap_set(bitmap, offset, sparity->nsectors - offset);
bitmap_set(bitmap, 0, nsectors - (sparity->nsectors - offset));
}
static inline void scrub_parity_mark_sectors_error(struct scrub_parity *sparity,
u64 start, u32 len)
2014-11-06 17:20:58 +08:00
{
__scrub_mark_bitmap(sparity, sparity->ebitmap, start, len);
}
static inline void scrub_parity_mark_sectors_data(struct scrub_parity *sparity,
u64 start, u32 len)
2014-11-06 17:20:58 +08:00
{
__scrub_mark_bitmap(sparity, sparity->dbitmap, start, len);
}
static void scrub_block_complete(struct scrub_block *sblock)
{
2014-11-06 17:20:58 +08:00
int corrupted = 0;
if (!sblock->no_io_error_seen) {
2014-11-06 17:20:58 +08:00
corrupted = 1;
scrub_handle_errored_block(sblock);
} else {
/*
* if has checksum error, write via repair mechanism in
* dev replace case, otherwise write here in dev replace
* case.
*/
2014-11-06 17:20:58 +08:00
corrupted = scrub_checksum(sblock);
if (!corrupted && sblock->sctx->is_dev_replace)
scrub_write_block_to_dev_replace(sblock);
}
2014-11-06 17:20:58 +08:00
if (sblock->sparity && corrupted && !sblock->data_corrected) {
u64 start = sblock->pagev[0]->logical;
u64 end = sblock->pagev[sblock->page_count - 1]->logical +
PAGE_SIZE;
ASSERT(end - start <= U32_MAX);
2014-11-06 17:20:58 +08:00
scrub_parity_mark_sectors_error(sblock->sparity,
start, end - start);
}
}
static void drop_csum_range(struct scrub_ctx *sctx, struct btrfs_ordered_sum *sum)
{
sctx->stat.csum_discards += sum->len >> sctx->fs_info->sectorsize_bits;
list_del(&sum->list);
kfree(sum);
}
/*
* Find the desired csum for range [logical, logical + sectorsize), and store
* the csum into @csum.
*
* The search source is sctx->csum_list, which is a pre-populated list
* storing bytenr ordered csum ranges. We're reponsible to cleanup any range
* that is before @logical.
*
* Return 0 if there is no csum for the range.
* Return 1 if there is csum for the range and copied to @csum.
*/
static int scrub_find_csum(struct scrub_ctx *sctx, u64 logical, u8 *csum)
{
bool found = false;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
while (!list_empty(&sctx->csum_list)) {
struct btrfs_ordered_sum *sum = NULL;
unsigned long index;
unsigned long num_sectors;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
sum = list_first_entry(&sctx->csum_list,
struct btrfs_ordered_sum, list);
/* The current csum range is beyond our range, no csum found */
if (sum->bytenr > logical)
break;
/*
* The current sum is before our bytenr, since scrub is always
* done in bytenr order, the csum will never be used anymore,
* clean it up so that later calls won't bother with the range,
* and continue search the next range.
*/
if (sum->bytenr + sum->len <= logical) {
drop_csum_range(sctx, sum);
continue;
}
/* Now the csum range covers our bytenr, copy the csum */
found = true;
index = (logical - sum->bytenr) >> sctx->fs_info->sectorsize_bits;
num_sectors = sum->len >> sctx->fs_info->sectorsize_bits;
memcpy(csum, sum->sums + index * sctx->fs_info->csum_size,
sctx->fs_info->csum_size);
/* Cleanup the range if we're at the end of the csum range */
if (index == num_sectors - 1)
drop_csum_range(sctx, sum);
break;
}
if (!found)
return 0;
return 1;
}
/* scrub extent tries to collect up to 64 kB for each bio */
static int scrub_extent(struct scrub_ctx *sctx, struct map_lookup *map,
u64 logical, u32 len,
u64 physical, struct btrfs_device *dev, u64 flags,
u64 gen, int mirror_num, u64 physical_for_dev_replace)
{
int ret;
u8 csum[BTRFS_CSUM_SIZE];
u32 blocksize;
if (flags & BTRFS_EXTENT_FLAG_DATA) {
if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
blocksize = map->stripe_len;
else
blocksize = sctx->fs_info->sectorsize;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
spin_lock(&sctx->stat_lock);
sctx->stat.data_extents_scrubbed++;
sctx->stat.data_bytes_scrubbed += len;
spin_unlock(&sctx->stat_lock);
} else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
blocksize = map->stripe_len;
else
blocksize = sctx->fs_info->nodesize;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
spin_lock(&sctx->stat_lock);
sctx->stat.tree_extents_scrubbed++;
sctx->stat.tree_bytes_scrubbed += len;
spin_unlock(&sctx->stat_lock);
} else {
blocksize = sctx->fs_info->sectorsize;
WARN_ON(1);
}
while (len) {
u32 l = min(len, blocksize);
int have_csum = 0;
if (flags & BTRFS_EXTENT_FLAG_DATA) {
/* push csums to sbio */
have_csum = scrub_find_csum(sctx, logical, csum);
if (have_csum == 0)
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
++sctx->stat.no_csum;
}
ret = scrub_pages(sctx, logical, l, physical, dev, flags, gen,
mirror_num, have_csum ? csum : NULL,
physical_for_dev_replace);
if (ret)
return ret;
len -= l;
logical += l;
physical += l;
physical_for_dev_replace += l;
}
return 0;
}
2014-11-06 17:20:58 +08:00
static int scrub_pages_for_parity(struct scrub_parity *sparity,
u64 logical, u32 len,
2014-11-06 17:20:58 +08:00
u64 physical, struct btrfs_device *dev,
u64 flags, u64 gen, int mirror_num, u8 *csum)
{
struct scrub_ctx *sctx = sparity->sctx;
struct scrub_block *sblock;
const u32 sectorsize = sctx->fs_info->sectorsize;
2014-11-06 17:20:58 +08:00
int index;
ASSERT(IS_ALIGNED(len, sectorsize));
sblock = kzalloc(sizeof(*sblock), GFP_KERNEL);
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if (!sblock) {
spin_lock(&sctx->stat_lock);
sctx->stat.malloc_errors++;
spin_unlock(&sctx->stat_lock);
return -ENOMEM;
}
/* one ref inside this function, plus one for each page added to
* a bio later on */
refcount_set(&sblock->refs, 1);
2014-11-06 17:20:58 +08:00
sblock->sctx = sctx;
sblock->no_io_error_seen = 1;
sblock->sparity = sparity;
scrub_parity_get(sparity);
for (index = 0; len > 0; index++) {
struct scrub_page *spage;
spage = kzalloc(sizeof(*spage), GFP_KERNEL);
2014-11-06 17:20:58 +08:00
if (!spage) {
leave_nomem:
spin_lock(&sctx->stat_lock);
sctx->stat.malloc_errors++;
spin_unlock(&sctx->stat_lock);
scrub_block_put(sblock);
return -ENOMEM;
}
BUG_ON(index >= SCRUB_MAX_PAGES_PER_BLOCK);
/* For scrub block */
scrub_page_get(spage);
sblock->pagev[index] = spage;
/* For scrub parity */
scrub_page_get(spage);
list_add_tail(&spage->list, &sparity->spages);
spage->sblock = sblock;
spage->dev = dev;
spage->flags = flags;
spage->generation = gen;
spage->logical = logical;
spage->physical = physical;
spage->mirror_num = mirror_num;
if (csum) {
spage->have_csum = 1;
memcpy(spage->csum, csum, sctx->fs_info->csum_size);
2014-11-06 17:20:58 +08:00
} else {
spage->have_csum = 0;
}
sblock->page_count++;
spage->page = alloc_page(GFP_KERNEL);
2014-11-06 17:20:58 +08:00
if (!spage->page)
goto leave_nomem;
/* Iterate over the stripe range in sectorsize steps */
len -= sectorsize;
logical += sectorsize;
physical += sectorsize;
2014-11-06 17:20:58 +08:00
}
WARN_ON(sblock->page_count == 0);
for (index = 0; index < sblock->page_count; index++) {
struct scrub_page *spage = sblock->pagev[index];
int ret;
ret = scrub_add_page_to_rd_bio(sctx, spage);
if (ret) {
scrub_block_put(sblock);
return ret;
}
}
/* last one frees, either here or in bio completion for last page */
scrub_block_put(sblock);
return 0;
}
static int scrub_extent_for_parity(struct scrub_parity *sparity,
u64 logical, u32 len,
2014-11-06 17:20:58 +08:00
u64 physical, struct btrfs_device *dev,
u64 flags, u64 gen, int mirror_num)
{
struct scrub_ctx *sctx = sparity->sctx;
int ret;
u8 csum[BTRFS_CSUM_SIZE];
u32 blocksize;
if (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state)) {
scrub_parity_mark_sectors_error(sparity, logical, len);
return 0;
}
2014-11-06 17:20:58 +08:00
if (flags & BTRFS_EXTENT_FLAG_DATA) {
blocksize = sparity->stripe_len;
2014-11-06 17:20:58 +08:00
} else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
blocksize = sparity->stripe_len;
2014-11-06 17:20:58 +08:00
} else {
blocksize = sctx->fs_info->sectorsize;
2014-11-06 17:20:58 +08:00
WARN_ON(1);
}
while (len) {
u32 l = min(len, blocksize);
2014-11-06 17:20:58 +08:00
int have_csum = 0;
if (flags & BTRFS_EXTENT_FLAG_DATA) {
/* push csums to sbio */
have_csum = scrub_find_csum(sctx, logical, csum);
2014-11-06 17:20:58 +08:00
if (have_csum == 0)
goto skip;
}
ret = scrub_pages_for_parity(sparity, logical, l, physical, dev,
flags, gen, mirror_num,
have_csum ? csum : NULL);
if (ret)
return ret;
skip:
2014-11-06 17:20:58 +08:00
len -= l;
logical += l;
physical += l;
}
return 0;
}
/*
* Given a physical address, this will calculate it's
* logical offset. if this is a parity stripe, it will return
* the most left data stripe's logical offset.
*
* return 0 if it is a data stripe, 1 means parity stripe.
*/
static int get_raid56_logic_offset(u64 physical, int num,
2014-11-06 17:20:58 +08:00
struct map_lookup *map, u64 *offset,
u64 *stripe_start)
{
int i;
int j = 0;
u64 stripe_nr;
u64 last_offset;
u32 stripe_index;
u32 rot;
const int data_stripes = nr_data_stripes(map);
last_offset = (physical - map->stripes[num].physical) * data_stripes;
2014-11-06 17:20:58 +08:00
if (stripe_start)
*stripe_start = last_offset;
*offset = last_offset;
for (i = 0; i < data_stripes; i++) {
*offset = last_offset + i * map->stripe_len;
stripe_nr = div64_u64(*offset, map->stripe_len);
stripe_nr = div_u64(stripe_nr, data_stripes);
/* Work out the disk rotation on this stripe-set */
stripe_nr = div_u64_rem(stripe_nr, map->num_stripes, &rot);
/* calculate which stripe this data locates */
rot += i;
stripe_index = rot % map->num_stripes;
if (stripe_index == num)
return 0;
if (stripe_index < num)
j++;
}
*offset = last_offset + j * map->stripe_len;
return 1;
}
2014-11-06 17:20:58 +08:00
static void scrub_free_parity(struct scrub_parity *sparity)
{
struct scrub_ctx *sctx = sparity->sctx;
struct scrub_page *curr, *next;
int nbits;
nbits = bitmap_weight(sparity->ebitmap, sparity->nsectors);
if (nbits) {
spin_lock(&sctx->stat_lock);
sctx->stat.read_errors += nbits;
sctx->stat.uncorrectable_errors += nbits;
spin_unlock(&sctx->stat_lock);
}
list_for_each_entry_safe(curr, next, &sparity->spages, list) {
list_del_init(&curr->list);
scrub_page_put(curr);
}
kfree(sparity);
}
btrfs: Fix lockdep warning of wr_ctx->wr_lock in scrub_free_wr_ctx() lockdep report following warning in test: [25176.843958] ================================= [25176.844519] [ INFO: inconsistent lock state ] [25176.845047] 4.1.0-rc3 #22 Tainted: G W [25176.845591] --------------------------------- [25176.846153] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. [25176.846713] fsstress/26661 [HC0[0]:SC1[1]:HE1:SE0] takes: [25176.847246] (&wr_ctx->wr_lock){+.?...}, at: [<ffffffffa04cdc6d>] scrub_free_ctx+0x2d/0xf0 [btrfs] [25176.847838] {SOFTIRQ-ON-W} state was registered at: [25176.848396] [<ffffffff810bf460>] __lock_acquire+0x6a0/0xe10 [25176.848955] [<ffffffff810bfd1e>] lock_acquire+0xce/0x2c0 [25176.849491] [<ffffffff816489af>] mutex_lock_nested+0x7f/0x410 [25176.850029] [<ffffffffa04d04ff>] scrub_stripe+0x4df/0x1080 [btrfs] [25176.850575] [<ffffffffa04d11b1>] scrub_chunk.isra.19+0x111/0x130 [btrfs] [25176.851110] [<ffffffffa04d144c>] scrub_enumerate_chunks+0x27c/0x510 [btrfs] [25176.851660] [<ffffffffa04d3b87>] btrfs_scrub_dev+0x1c7/0x6c0 [btrfs] [25176.852189] [<ffffffffa04e918e>] btrfs_dev_replace_start+0x36e/0x450 [btrfs] [25176.852771] [<ffffffffa04a98e0>] btrfs_ioctl+0x1e10/0x2d20 [btrfs] [25176.853315] [<ffffffff8121c5b8>] do_vfs_ioctl+0x318/0x570 [25176.853868] [<ffffffff8121c851>] SyS_ioctl+0x41/0x80 [25176.854406] [<ffffffff8164da17>] system_call_fastpath+0x12/0x6f [25176.854935] irq event stamp: 51506 [25176.855511] hardirqs last enabled at (51506): [<ffffffff810d4ce5>] vprintk_emit+0x225/0x5e0 [25176.856059] hardirqs last disabled at (51505): [<ffffffff810d4b77>] vprintk_emit+0xb7/0x5e0 [25176.856642] softirqs last enabled at (50886): [<ffffffff81067a23>] __do_softirq+0x363/0x640 [25176.857184] softirqs last disabled at (50949): [<ffffffff8106804d>] irq_exit+0x10d/0x120 [25176.857746] other info that might help us debug this: [25176.858845] Possible unsafe locking scenario: [25176.859981] CPU0 [25176.860537] ---- [25176.861059] lock(&wr_ctx->wr_lock); [25176.861705] <Interrupt> [25176.862272] lock(&wr_ctx->wr_lock); [25176.862881] *** DEADLOCK *** Reason: Above warning is caused by: Interrupt -> bio_endio() -> ... -> scrub_put_ctx() -> scrub_free_ctx() *1 -> ... -> mutex_lock(&wr_ctx->wr_lock); scrub_put_ctx() is allowed to be called in end_bio interrupt, but in code design, it will never call scrub_free_ctx(sctx) in interrupe context(above *1), because btrfs_scrub_dev() get one additional reference of sctx->refs, which makes scrub_free_ctx() only called withine btrfs_scrub_dev(). Now the code runs out of our wish, because free sequence in scrub_pending_bio_dec() have a gap. Current code: -----------------------------------+----------------------------------- scrub_pending_bio_dec() | btrfs_scrub_dev -----------------------------------+----------------------------------- atomic_dec(&sctx->bios_in_flight); | wake_up(&sctx->list_wait); | | scrub_put_ctx() | -> atomic_dec_and_test(&sctx->refs) scrub_put_ctx(sctx); | -> atomic_dec_and_test(&sctx->refs)| -> scrub_free_ctx() | -----------------------------------+----------------------------------- We expected: -----------------------------------+----------------------------------- scrub_pending_bio_dec() | btrfs_scrub_dev -----------------------------------+----------------------------------- atomic_dec(&sctx->bios_in_flight); | wake_up(&sctx->list_wait); | scrub_put_ctx(sctx); | -> atomic_dec_and_test(&sctx->refs)| | scrub_put_ctx() | -> atomic_dec_and_test(&sctx->refs) | -> scrub_free_ctx() -----------------------------------+----------------------------------- Fix: Move scrub_pending_bio_dec() to a workqueue, to avoid this function run in interrupt context. Tested by check tracelog in debug. Changelog v1->v2: Use workqueue instead of adjust function call sequence in v1, because v1 will introduce a bug pointed out by: Filipe David Manana <fdmanana@gmail.com> Reported-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-06-04 20:09:15 +08:00
static void scrub_parity_bio_endio_worker(struct btrfs_work *work)
{
struct scrub_parity *sparity = container_of(work, struct scrub_parity,
work);
struct scrub_ctx *sctx = sparity->sctx;
scrub_free_parity(sparity);
scrub_pending_bio_dec(sctx);
}
static void scrub_parity_bio_endio(struct bio *bio)
2014-11-06 17:20:58 +08:00
{
struct scrub_parity *sparity = (struct scrub_parity *)bio->bi_private;
struct btrfs_fs_info *fs_info = sparity->sctx->fs_info;
2014-11-06 17:20:58 +08:00
if (bio->bi_status)
2014-11-06 17:20:58 +08:00
bitmap_or(sparity->ebitmap, sparity->ebitmap, sparity->dbitmap,
sparity->nsectors);
bio_put(bio);
btrfs: Fix lockdep warning of wr_ctx->wr_lock in scrub_free_wr_ctx() lockdep report following warning in test: [25176.843958] ================================= [25176.844519] [ INFO: inconsistent lock state ] [25176.845047] 4.1.0-rc3 #22 Tainted: G W [25176.845591] --------------------------------- [25176.846153] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. [25176.846713] fsstress/26661 [HC0[0]:SC1[1]:HE1:SE0] takes: [25176.847246] (&wr_ctx->wr_lock){+.?...}, at: [<ffffffffa04cdc6d>] scrub_free_ctx+0x2d/0xf0 [btrfs] [25176.847838] {SOFTIRQ-ON-W} state was registered at: [25176.848396] [<ffffffff810bf460>] __lock_acquire+0x6a0/0xe10 [25176.848955] [<ffffffff810bfd1e>] lock_acquire+0xce/0x2c0 [25176.849491] [<ffffffff816489af>] mutex_lock_nested+0x7f/0x410 [25176.850029] [<ffffffffa04d04ff>] scrub_stripe+0x4df/0x1080 [btrfs] [25176.850575] [<ffffffffa04d11b1>] scrub_chunk.isra.19+0x111/0x130 [btrfs] [25176.851110] [<ffffffffa04d144c>] scrub_enumerate_chunks+0x27c/0x510 [btrfs] [25176.851660] [<ffffffffa04d3b87>] btrfs_scrub_dev+0x1c7/0x6c0 [btrfs] [25176.852189] [<ffffffffa04e918e>] btrfs_dev_replace_start+0x36e/0x450 [btrfs] [25176.852771] [<ffffffffa04a98e0>] btrfs_ioctl+0x1e10/0x2d20 [btrfs] [25176.853315] [<ffffffff8121c5b8>] do_vfs_ioctl+0x318/0x570 [25176.853868] [<ffffffff8121c851>] SyS_ioctl+0x41/0x80 [25176.854406] [<ffffffff8164da17>] system_call_fastpath+0x12/0x6f [25176.854935] irq event stamp: 51506 [25176.855511] hardirqs last enabled at (51506): [<ffffffff810d4ce5>] vprintk_emit+0x225/0x5e0 [25176.856059] hardirqs last disabled at (51505): [<ffffffff810d4b77>] vprintk_emit+0xb7/0x5e0 [25176.856642] softirqs last enabled at (50886): [<ffffffff81067a23>] __do_softirq+0x363/0x640 [25176.857184] softirqs last disabled at (50949): [<ffffffff8106804d>] irq_exit+0x10d/0x120 [25176.857746] other info that might help us debug this: [25176.858845] Possible unsafe locking scenario: [25176.859981] CPU0 [25176.860537] ---- [25176.861059] lock(&wr_ctx->wr_lock); [25176.861705] <Interrupt> [25176.862272] lock(&wr_ctx->wr_lock); [25176.862881] *** DEADLOCK *** Reason: Above warning is caused by: Interrupt -> bio_endio() -> ... -> scrub_put_ctx() -> scrub_free_ctx() *1 -> ... -> mutex_lock(&wr_ctx->wr_lock); scrub_put_ctx() is allowed to be called in end_bio interrupt, but in code design, it will never call scrub_free_ctx(sctx) in interrupe context(above *1), because btrfs_scrub_dev() get one additional reference of sctx->refs, which makes scrub_free_ctx() only called withine btrfs_scrub_dev(). Now the code runs out of our wish, because free sequence in scrub_pending_bio_dec() have a gap. Current code: -----------------------------------+----------------------------------- scrub_pending_bio_dec() | btrfs_scrub_dev -----------------------------------+----------------------------------- atomic_dec(&sctx->bios_in_flight); | wake_up(&sctx->list_wait); | | scrub_put_ctx() | -> atomic_dec_and_test(&sctx->refs) scrub_put_ctx(sctx); | -> atomic_dec_and_test(&sctx->refs)| -> scrub_free_ctx() | -----------------------------------+----------------------------------- We expected: -----------------------------------+----------------------------------- scrub_pending_bio_dec() | btrfs_scrub_dev -----------------------------------+----------------------------------- atomic_dec(&sctx->bios_in_flight); | wake_up(&sctx->list_wait); | scrub_put_ctx(sctx); | -> atomic_dec_and_test(&sctx->refs)| | scrub_put_ctx() | -> atomic_dec_and_test(&sctx->refs) | -> scrub_free_ctx() -----------------------------------+----------------------------------- Fix: Move scrub_pending_bio_dec() to a workqueue, to avoid this function run in interrupt context. Tested by check tracelog in debug. Changelog v1->v2: Use workqueue instead of adjust function call sequence in v1, because v1 will introduce a bug pointed out by: Filipe David Manana <fdmanana@gmail.com> Reported-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-06-04 20:09:15 +08:00
btrfs_init_work(&sparity->work, scrub_parity_bio_endio_worker, NULL,
NULL);
btrfs_queue_work(fs_info->scrub_parity_workers, &sparity->work);
2014-11-06 17:20:58 +08:00
}
static void scrub_parity_check_and_repair(struct scrub_parity *sparity)
{
struct scrub_ctx *sctx = sparity->sctx;
struct btrfs_fs_info *fs_info = sctx->fs_info;
2014-11-06 17:20:58 +08:00
struct bio *bio;
struct btrfs_raid_bio *rbio;
struct btrfs_bio *bbio = NULL;
u64 length;
int ret;
if (!bitmap_andnot(sparity->dbitmap, sparity->dbitmap, sparity->ebitmap,
sparity->nsectors))
goto out;
length = sparity->logic_end - sparity->logic_start;
btrfs: Wait for in-flight bios before freeing target device for raid56 When raid56 dev-replace is cancelled by running scrub, we will free target device without waiting for in-flight bios, causing the following NULL pointer deference or general protection failure. BUG: unable to handle kernel NULL pointer dereference at 00000000000005e0 IP: generic_make_request_checks+0x4d/0x610 CPU: 1 PID: 11676 Comm: kworker/u4:14 Tainted: G O 4.11.0-rc2 #72 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.2-20170228_101828-anatol 04/01/2014 Workqueue: btrfs-endio-raid56 btrfs_endio_raid56_helper [btrfs] task: ffff88002875b4c0 task.stack: ffffc90001334000 RIP: 0010:generic_make_request_checks+0x4d/0x610 Call Trace: ? generic_make_request+0xc7/0x360 generic_make_request+0x24/0x360 ? generic_make_request+0xc7/0x360 submit_bio+0x64/0x120 ? page_in_rbio+0x4d/0x80 [btrfs] ? rbio_orig_end_io+0x80/0x80 [btrfs] finish_rmw+0x3f4/0x540 [btrfs] validate_rbio_for_rmw+0x36/0x40 [btrfs] raid_rmw_end_io+0x7a/0x90 [btrfs] bio_endio+0x56/0x60 end_workqueue_fn+0x3c/0x40 [btrfs] btrfs_scrubparity_helper+0xef/0x620 [btrfs] btrfs_endio_raid56_helper+0xe/0x10 [btrfs] process_one_work+0x2af/0x720 ? process_one_work+0x22b/0x720 worker_thread+0x4b/0x4f0 kthread+0x10f/0x150 ? process_one_work+0x720/0x720 ? kthread_create_on_node+0x40/0x40 ret_from_fork+0x2e/0x40 RIP: generic_make_request_checks+0x4d/0x610 RSP: ffffc90001337bb8 In btrfs_dev_replace_finishing(), we will call btrfs_rm_dev_replace_blocked() to wait bios before destroying the target device when scrub is finished normally. However when dev-replace is aborted, either due to error or cancelled by scrub, we didn't wait for bios, this can lead to use-after-free if there are bios holding the target device. Furthermore, for raid56 scrub, at least 2 places are calling btrfs_map_sblock() without protection of bio_counter, leading to the problem. This patch fixes the problem: 1) Wait for bio_counter before freeing target device when canceling replace 2) When calling btrfs_map_sblock() for raid56, use bio_counter to protect the call. Cc: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-03-29 09:33:21 +08:00
btrfs_bio_counter_inc_blocked(fs_info);
ret = btrfs_map_sblock(fs_info, BTRFS_MAP_WRITE, sparity->logic_start,
&length, &bbio);
if (ret || !bbio || !bbio->raid_map)
2014-11-06 17:20:58 +08:00
goto bbio_out;
bio = btrfs_io_bio_alloc(0);
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bio->bi_iter.bi_sector = sparity->logic_start >> 9;
bio->bi_private = sparity;
bio->bi_end_io = scrub_parity_bio_endio;
rbio = raid56_parity_alloc_scrub_rbio(fs_info, bio, bbio,
length, sparity->scrub_dev,
2014-11-06 17:20:58 +08:00
sparity->dbitmap,
sparity->nsectors);
if (!rbio)
goto rbio_out;
scrub_pending_bio_inc(sctx);
raid56_parity_submit_scrub_rbio(rbio);
return;
rbio_out:
bio_put(bio);
bbio_out:
btrfs: Wait for in-flight bios before freeing target device for raid56 When raid56 dev-replace is cancelled by running scrub, we will free target device without waiting for in-flight bios, causing the following NULL pointer deference or general protection failure. BUG: unable to handle kernel NULL pointer dereference at 00000000000005e0 IP: generic_make_request_checks+0x4d/0x610 CPU: 1 PID: 11676 Comm: kworker/u4:14 Tainted: G O 4.11.0-rc2 #72 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.2-20170228_101828-anatol 04/01/2014 Workqueue: btrfs-endio-raid56 btrfs_endio_raid56_helper [btrfs] task: ffff88002875b4c0 task.stack: ffffc90001334000 RIP: 0010:generic_make_request_checks+0x4d/0x610 Call Trace: ? generic_make_request+0xc7/0x360 generic_make_request+0x24/0x360 ? generic_make_request+0xc7/0x360 submit_bio+0x64/0x120 ? page_in_rbio+0x4d/0x80 [btrfs] ? rbio_orig_end_io+0x80/0x80 [btrfs] finish_rmw+0x3f4/0x540 [btrfs] validate_rbio_for_rmw+0x36/0x40 [btrfs] raid_rmw_end_io+0x7a/0x90 [btrfs] bio_endio+0x56/0x60 end_workqueue_fn+0x3c/0x40 [btrfs] btrfs_scrubparity_helper+0xef/0x620 [btrfs] btrfs_endio_raid56_helper+0xe/0x10 [btrfs] process_one_work+0x2af/0x720 ? process_one_work+0x22b/0x720 worker_thread+0x4b/0x4f0 kthread+0x10f/0x150 ? process_one_work+0x720/0x720 ? kthread_create_on_node+0x40/0x40 ret_from_fork+0x2e/0x40 RIP: generic_make_request_checks+0x4d/0x610 RSP: ffffc90001337bb8 In btrfs_dev_replace_finishing(), we will call btrfs_rm_dev_replace_blocked() to wait bios before destroying the target device when scrub is finished normally. However when dev-replace is aborted, either due to error or cancelled by scrub, we didn't wait for bios, this can lead to use-after-free if there are bios holding the target device. Furthermore, for raid56 scrub, at least 2 places are calling btrfs_map_sblock() without protection of bio_counter, leading to the problem. This patch fixes the problem: 1) Wait for bio_counter before freeing target device when canceling replace 2) When calling btrfs_map_sblock() for raid56, use bio_counter to protect the call. Cc: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-03-29 09:33:21 +08:00
btrfs_bio_counter_dec(fs_info);
btrfs_put_bbio(bbio);
2014-11-06 17:20:58 +08:00
bitmap_or(sparity->ebitmap, sparity->ebitmap, sparity->dbitmap,
sparity->nsectors);
spin_lock(&sctx->stat_lock);
sctx->stat.malloc_errors++;
spin_unlock(&sctx->stat_lock);
out:
scrub_free_parity(sparity);
}
static inline int scrub_calc_parity_bitmap_len(int nsectors)
{
return DIV_ROUND_UP(nsectors, BITS_PER_LONG) * sizeof(long);
2014-11-06 17:20:58 +08:00
}
static void scrub_parity_get(struct scrub_parity *sparity)
{
refcount_inc(&sparity->refs);
2014-11-06 17:20:58 +08:00
}
static void scrub_parity_put(struct scrub_parity *sparity)
{
if (!refcount_dec_and_test(&sparity->refs))
2014-11-06 17:20:58 +08:00
return;
scrub_parity_check_and_repair(sparity);
}
static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx,
struct map_lookup *map,
struct btrfs_device *sdev,
struct btrfs_path *path,
u64 logic_start,
u64 logic_end)
{
struct btrfs_fs_info *fs_info = sctx->fs_info;
2014-11-06 17:20:58 +08:00
struct btrfs_root *root = fs_info->extent_root;
struct btrfs_root *csum_root = fs_info->csum_root;
struct btrfs_extent_item *extent;
struct btrfs_bio *bbio = NULL;
2014-11-06 17:20:58 +08:00
u64 flags;
int ret;
int slot;
struct extent_buffer *l;
struct btrfs_key key;
u64 generation;
u64 extent_logical;
u64 extent_physical;
/* Check the comment in scrub_stripe() for why u32 is enough here */
u32 extent_len;
u64 mapped_length;
2014-11-06 17:20:58 +08:00
struct btrfs_device *extent_dev;
struct scrub_parity *sparity;
int nsectors;
int bitmap_len;
int extent_mirror_num;
int stop_loop = 0;
ASSERT(map->stripe_len <= U32_MAX);
nsectors = map->stripe_len >> fs_info->sectorsize_bits;
2014-11-06 17:20:58 +08:00
bitmap_len = scrub_calc_parity_bitmap_len(nsectors);
sparity = kzalloc(sizeof(struct scrub_parity) + 2 * bitmap_len,
GFP_NOFS);
if (!sparity) {
spin_lock(&sctx->stat_lock);
sctx->stat.malloc_errors++;
spin_unlock(&sctx->stat_lock);
return -ENOMEM;
}
ASSERT(map->stripe_len <= U32_MAX);
2014-11-06 17:20:58 +08:00
sparity->stripe_len = map->stripe_len;
sparity->nsectors = nsectors;
sparity->sctx = sctx;
sparity->scrub_dev = sdev;
sparity->logic_start = logic_start;
sparity->logic_end = logic_end;
refcount_set(&sparity->refs, 1);
2014-11-06 17:20:58 +08:00
INIT_LIST_HEAD(&sparity->spages);
sparity->dbitmap = sparity->bitmap;
sparity->ebitmap = (void *)sparity->bitmap + bitmap_len;
ret = 0;
while (logic_start < logic_end) {
if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
key.type = BTRFS_METADATA_ITEM_KEY;
else
key.type = BTRFS_EXTENT_ITEM_KEY;
key.objectid = logic_start;
key.offset = (u64)-1;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
if (ret > 0) {
ret = btrfs_previous_extent_item(root, path, 0);
if (ret < 0)
goto out;
if (ret > 0) {
btrfs_release_path(path);
ret = btrfs_search_slot(NULL, root, &key,
path, 0, 0);
if (ret < 0)
goto out;
}
}
stop_loop = 0;
while (1) {
u64 bytes;
l = path->nodes[0];
slot = path->slots[0];
if (slot >= btrfs_header_nritems(l)) {
ret = btrfs_next_leaf(root, path);
if (ret == 0)
continue;
if (ret < 0)
goto out;
stop_loop = 1;
break;
}
btrfs_item_key_to_cpu(l, &key, slot);
if (key.type != BTRFS_EXTENT_ITEM_KEY &&
key.type != BTRFS_METADATA_ITEM_KEY)
goto next;
2014-11-06 17:20:58 +08:00
if (key.type == BTRFS_METADATA_ITEM_KEY)
bytes = fs_info->nodesize;
2014-11-06 17:20:58 +08:00
else
bytes = key.offset;
if (key.objectid + bytes <= logic_start)
goto next;
if (key.objectid >= logic_end) {
2014-11-06 17:20:58 +08:00
stop_loop = 1;
break;
}
while (key.objectid >= logic_start + map->stripe_len)
logic_start += map->stripe_len;
extent = btrfs_item_ptr(l, slot,
struct btrfs_extent_item);
flags = btrfs_extent_flags(l, extent);
generation = btrfs_extent_generation(l, extent);
btrfs: Fix scrub panic when leaf crosses stripes Scrub panic in following operation: mkfs.ext4 /dev/vdh btrfs-convert /dev/vdh mount /dev/vdh /mnt/tmp1 btrfs scrub start -B /dev/vdh (panic) Reason: 1: In some case, leaf created by btrfs-convert was splited into 2 strips. 2: Scrub bypassed part of above wrong leaf data, but remain data caused panic in scrub_checksum_tree_block(). For reason 1: we can get following information after some simple operation. a. mkfs.ext4 /dev/vdh btrfs-convert /dev/vdh b. btrfs-debug-tree /dev/vdh we can see following item in extent tree: item 25 key (27054080 METADATA_ITEM 0) itemoff 15083 itemsize 33 Its logical address is [27054080, 27070464) and acrossed 2 strips: [27000832, 27066368) [27066368, 27131904) Will be fixed in btrfs-progs(btrfs-convert, btrfsck, ...) For reason 2: Scrub is trying to do a "bypass" in this case, but the result is "panic", because current code lacks of some condition in bypass, and let some wrong leaf data escaped. This patch fixed above scrub code. Before patch: # btrfs scrub start -B /dev/vdh (panic) After patch: # btrfs scrub start -B /dev/vdh scrub done for 353cec8f-da31-4a94-aa35-be72d997b06e ... # dmesg ... [ 59.088697] BTRFS error (device vdh): scrub: tree block 27054080 spanning stripes, ignored. logical=27000832 [ 59.089929] BTRFS error (device vdh): scrub: tree block 27054080 spanning stripes, ignored. logical=27066368 # Reported-by: Chris Murphy <lists@colorremedies.com> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-07-23 12:29:49 +08:00
if ((flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) &&
(key.objectid < logic_start ||
key.objectid + bytes >
logic_start + map->stripe_len)) {
btrfs_err(fs_info,
"scrub: tree block %llu spanning stripes, ignored. logical=%llu",
btrfs: Fix scrub panic when leaf crosses stripes Scrub panic in following operation: mkfs.ext4 /dev/vdh btrfs-convert /dev/vdh mount /dev/vdh /mnt/tmp1 btrfs scrub start -B /dev/vdh (panic) Reason: 1: In some case, leaf created by btrfs-convert was splited into 2 strips. 2: Scrub bypassed part of above wrong leaf data, but remain data caused panic in scrub_checksum_tree_block(). For reason 1: we can get following information after some simple operation. a. mkfs.ext4 /dev/vdh btrfs-convert /dev/vdh b. btrfs-debug-tree /dev/vdh we can see following item in extent tree: item 25 key (27054080 METADATA_ITEM 0) itemoff 15083 itemsize 33 Its logical address is [27054080, 27070464) and acrossed 2 strips: [27000832, 27066368) [27066368, 27131904) Will be fixed in btrfs-progs(btrfs-convert, btrfsck, ...) For reason 2: Scrub is trying to do a "bypass" in this case, but the result is "panic", because current code lacks of some condition in bypass, and let some wrong leaf data escaped. This patch fixed above scrub code. Before patch: # btrfs scrub start -B /dev/vdh (panic) After patch: # btrfs scrub start -B /dev/vdh scrub done for 353cec8f-da31-4a94-aa35-be72d997b06e ... # dmesg ... [ 59.088697] BTRFS error (device vdh): scrub: tree block 27054080 spanning stripes, ignored. logical=27000832 [ 59.089929] BTRFS error (device vdh): scrub: tree block 27054080 spanning stripes, ignored. logical=27066368 # Reported-by: Chris Murphy <lists@colorremedies.com> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-07-23 12:29:49 +08:00
key.objectid, logic_start);
spin_lock(&sctx->stat_lock);
sctx->stat.uncorrectable_errors++;
spin_unlock(&sctx->stat_lock);
2014-11-06 17:20:58 +08:00
goto next;
}
again:
extent_logical = key.objectid;
ASSERT(bytes <= U32_MAX);
2014-11-06 17:20:58 +08:00
extent_len = bytes;
if (extent_logical < logic_start) {
extent_len -= logic_start - extent_logical;
extent_logical = logic_start;
}
if (extent_logical + extent_len >
logic_start + map->stripe_len)
extent_len = logic_start + map->stripe_len -
extent_logical;
scrub_parity_mark_sectors_data(sparity, extent_logical,
extent_len);
mapped_length = extent_len;
bbio = NULL;
ret = btrfs_map_block(fs_info, BTRFS_MAP_READ,
extent_logical, &mapped_length, &bbio,
0);
if (!ret) {
if (!bbio || mapped_length < extent_len)
ret = -EIO;
}
if (ret) {
btrfs_put_bbio(bbio);
goto out;
}
extent_physical = bbio->stripes[0].physical;
extent_mirror_num = bbio->mirror_num;
extent_dev = bbio->stripes[0].dev;
btrfs_put_bbio(bbio);
2014-11-06 17:20:58 +08:00
ret = btrfs_lookup_csums_range(csum_root,
extent_logical,
extent_logical + extent_len - 1,
&sctx->csum_list, 1);
if (ret)
goto out;
ret = scrub_extent_for_parity(sparity, extent_logical,
extent_len,
extent_physical,
extent_dev, flags,
generation,
extent_mirror_num);
scrub_free_csums(sctx);
2014-11-06 17:20:58 +08:00
if (ret)
goto out;
if (extent_logical + extent_len <
key.objectid + bytes) {
logic_start += map->stripe_len;
if (logic_start >= logic_end) {
stop_loop = 1;
break;
}
if (logic_start < key.objectid + bytes) {
cond_resched();
goto again;
}
}
next:
path->slots[0]++;
}
btrfs_release_path(path);
if (stop_loop)
break;
logic_start += map->stripe_len;
}
out:
if (ret < 0) {
ASSERT(logic_end - logic_start <= U32_MAX);
2014-11-06 17:20:58 +08:00
scrub_parity_mark_sectors_error(sparity, logic_start,
logic_end - logic_start);
}
2014-11-06 17:20:58 +08:00
scrub_parity_put(sparity);
scrub_submit(sctx);
mutex_lock(&sctx->wr_lock);
2014-11-06 17:20:58 +08:00
scrub_wr_submit(sctx);
mutex_unlock(&sctx->wr_lock);
2014-11-06 17:20:58 +08:00
btrfs_release_path(path);
return ret < 0 ? ret : 0;
}
static void sync_replace_for_zoned(struct scrub_ctx *sctx)
{
if (!btrfs_is_zoned(sctx->fs_info))
return;
sctx->flush_all_writes = true;
scrub_submit(sctx);
mutex_lock(&sctx->wr_lock);
scrub_wr_submit(sctx);
mutex_unlock(&sctx->wr_lock);
wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
}
static int sync_write_pointer_for_zoned(struct scrub_ctx *sctx, u64 logical,
u64 physical, u64 physical_end)
{
struct btrfs_fs_info *fs_info = sctx->fs_info;
int ret = 0;
if (!btrfs_is_zoned(fs_info))
return 0;
wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
mutex_lock(&sctx->wr_lock);
if (sctx->write_pointer < physical_end) {
ret = btrfs_sync_zone_write_pointer(sctx->wr_tgtdev, logical,
physical,
sctx->write_pointer);
if (ret)
btrfs_err(fs_info,
"zoned: failed to recover write pointer");
}
mutex_unlock(&sctx->wr_lock);
btrfs_dev_clear_zone_empty(sctx->wr_tgtdev, physical);
return ret;
}
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
struct map_lookup *map,
struct btrfs_device *scrub_dev,
btrfs: fix a race between scrub and block group removal/allocation When scrub is verifying the extents of a block group for a device, it is possible that the corresponding block group gets removed and its logical address and device extents get used for a new block group allocation. When this happens scrub incorrectly reports that errors were detected and, if the the new block group has a different profile then the old one, deleted block group, we can crash due to a null pointer dereference. Possibly other unexpected and weird consequences can happen as well. Consider the following sequence of actions that leads to the null pointer dereference crash when scrub is running in parallel with balance: 1) Balance sets block group X to read-only mode and starts relocating it. Block group X is a metadata block group, has a raid1 profile (two device extents, each one in a different device) and a logical address of 19424870400; 2) Scrub is running and finds device extent E, which belongs to block group X. It enters scrub_stripe() to find all extents allocated to block group X, the search is done using the extent tree; 3) Balance finishes relocating block group X and removes block group X; 4) Balance starts relocating another block group and when trying to commit the current transaction as part of the preparation step (prepare_to_relocate()), it blocks because scrub is running; 5) The scrub task finds the metadata extent at the logical address 19425001472 and marks the pages of the extent to be read by a bio (struct scrub_bio). The extent item's flags, which have the bit BTRFS_EXTENT_FLAG_TREE_BLOCK set, are added to each page (struct scrub_page). It is these flags in the scrub pages that tells the bio's end io function (scrub_bio_end_io_worker) which type of extent it is dealing with. At this point we end up with 4 pages in a bio which is ready for submission (the metadata extent has a size of 16Kb, so that gives 4 pages on x86); 6) At the next iteration of scrub_stripe(), scrub checks that there is a pause request from the relocation task trying to commit a transaction, therefore it submits the pending bio and pauses, waiting for the transaction commit to complete before resuming; 7) The relocation task commits the transaction. The device extent E, that was used by our block group X, is now available for allocation, since the commit root for the device tree was swapped by the transaction commit; 8) Another task doing a direct IO write allocates a new data block group Y which ends using device extent E. This new block group Y also ends up getting the same logical address that block group X had: 19424870400. This happens because block group X was the block group with the highest logical address and, when allocating Y, find_next_chunk() returns the end offset of the current last block group to be used as the logical address for the new block group, which is 18351128576 + 1073741824 = 19424870400 So our new block group Y has the same logical address and device extent that block group X had. However Y is a data block group, while X was a metadata one, and Y has a raid0 profile, while X had a raid1 profile; 9) After allocating block group Y, the direct IO submits a bio to write to device extent E; 10) The read bio submitted by scrub reads the 4 pages (16Kb) from device extent E, which now correspond to the data written by the task that did a direct IO write. Then at the end io function associated with the bio, scrub_bio_end_io_worker(), we call scrub_block_complete() which calls scrub_checksum(). This later function checks the flags of the first page, and sees that the bit BTRFS_EXTENT_FLAG_TREE_BLOCK is set in the flags, so it assumes it has a metadata extent and then calls scrub_checksum_tree_block(). That functions returns an error, since interpreting data as a metadata extent causes the checksum verification to fail. So this makes scrub_checksum() call scrub_handle_errored_block(), which determines 'failed_mirror_index' to be 1, since the device extent E was allocated as the second mirror of block group X. It allocates BTRFS_MAX_MIRRORS scrub_block structures as an array at 'sblocks_for_recheck', and all the memory is initialized to zeroes by kcalloc(). After that it calls scrub_setup_recheck_block(), which is responsible for filling each of those structures. However, when that function calls btrfs_map_sblock() against the logical address of the metadata extent, 19425001472, it gets a struct btrfs_bio ('bbio') that matches the current block group Y. However block group Y has a raid0 profile and not a raid1 profile like X had, so the following call returns 1: scrub_nr_raid_mirrors(bbio) And as a result scrub_setup_recheck_block() only initializes the first (index 0) scrub_block structure in 'sblocks_for_recheck'. Then scrub_recheck_block() is called by scrub_handle_errored_block() with the second (index 1) scrub_block structure as the argument, because 'failed_mirror_index' was previously set to 1. This scrub_block was not initialized by scrub_setup_recheck_block(), so it has zero pages, its 'page_count' member is 0 and its 'pagev' page array has all members pointing to NULL. Finally when scrub_recheck_block() calls scrub_recheck_block_checksum() we have a NULL pointer dereference when accessing the flags of the first page, as pavev[0] is NULL: static void scrub_recheck_block_checksum(struct scrub_block *sblock) { (...) if (sblock->pagev[0]->flags & BTRFS_EXTENT_FLAG_DATA) scrub_checksum_data(sblock); (...) } Producing a stack trace like the following: [542998.008985] BUG: kernel NULL pointer dereference, address: 0000000000000028 [542998.010238] #PF: supervisor read access in kernel mode [542998.010878] #PF: error_code(0x0000) - not-present page [542998.011516] PGD 0 P4D 0 [542998.011929] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI [542998.012786] CPU: 3 PID: 4846 Comm: kworker/u8:1 Tainted: G B W 5.6.0-rc7-btrfs-next-58 #1 [542998.014524] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 [542998.016065] Workqueue: btrfs-scrub btrfs_work_helper [btrfs] [542998.017255] RIP: 0010:scrub_recheck_block_checksum+0xf/0x20 [btrfs] [542998.018474] Code: 4c 89 e6 ... [542998.021419] RSP: 0018:ffffa7af0375fbd8 EFLAGS: 00010202 [542998.022120] RAX: 0000000000000000 RBX: ffff9792e674d120 RCX: 0000000000000000 [542998.023178] RDX: 0000000000000001 RSI: ffff9792e674d120 RDI: ffff9792e674d120 [542998.024465] RBP: 0000000000000000 R08: 0000000000000067 R09: 0000000000000001 [542998.025462] R10: ffffa7af0375fa50 R11: 0000000000000000 R12: ffff9791f61fe800 [542998.026357] R13: ffff9792e674d120 R14: 0000000000000001 R15: ffffffffc0e3dfc0 [542998.027237] FS: 0000000000000000(0000) GS:ffff9792fb200000(0000) knlGS:0000000000000000 [542998.028327] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [542998.029261] CR2: 0000000000000028 CR3: 00000000b3b18003 CR4: 00000000003606e0 [542998.030301] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [542998.031316] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [542998.032380] Call Trace: [542998.032752] scrub_recheck_block+0x162/0x400 [btrfs] [542998.033500] ? __alloc_pages_nodemask+0x31e/0x460 [542998.034228] scrub_handle_errored_block+0x6f8/0x1920 [btrfs] [542998.035170] scrub_bio_end_io_worker+0x100/0x520 [btrfs] [542998.035991] btrfs_work_helper+0xaa/0x720 [btrfs] [542998.036735] process_one_work+0x26d/0x6a0 [542998.037275] worker_thread+0x4f/0x3e0 [542998.037740] ? process_one_work+0x6a0/0x6a0 [542998.038378] kthread+0x103/0x140 [542998.038789] ? kthread_create_worker_on_cpu+0x70/0x70 [542998.039419] ret_from_fork+0x3a/0x50 [542998.039875] Modules linked in: dm_snapshot dm_thin_pool ... [542998.047288] CR2: 0000000000000028 [542998.047724] ---[ end trace bde186e176c7f96a ]--- This issue has been around for a long time, possibly since scrub exists. The last time I ran into it was over 2 years ago. After recently fixing fstests to pass the "--full-balance" command line option to btrfs-progs when doing balance, several tests started to more heavily exercise balance with fsstress, scrub and other operations in parallel, and therefore started to hit this issue again (with btrfs/061 for example). Fix this by having scrub increment the 'trimming' counter of the block group, which pins the block group in such a way that it guarantees neither its logical address nor device extents can be reused by future block group allocations until we decrement the 'trimming' counter. Also make sure that on each iteration of scrub_stripe() we stop scrubbing the block group if it was removed already. A later patch in the series will rename the block group's 'trimming' counter and its helpers to a more generic name, since now it is not used exclusively for pinning while trimming anymore. CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-08 18:01:10 +08:00
int num, u64 base, u64 length,
struct btrfs_block_group *cache)
{
2014-11-06 17:20:58 +08:00
struct btrfs_path *path, *ppath;
struct btrfs_fs_info *fs_info = sctx->fs_info;
struct btrfs_root *root = fs_info->extent_root;
struct btrfs_root *csum_root = fs_info->csum_root;
struct btrfs_extent_item *extent;
struct blk_plug plug;
u64 flags;
int ret;
int slot;
u64 nstripes;
struct extent_buffer *l;
u64 physical;
u64 logical;
u64 logic_end;
u64 physical_end;
u64 generation;
int mirror_num;
struct reada_control *reada1;
struct reada_control *reada2;
struct btrfs_key key;
struct btrfs_key key_end;
u64 increment = map->stripe_len;
u64 offset;
u64 extent_logical;
u64 extent_physical;
/*
* Unlike chunk length, extent length should never go beyond
* BTRFS_MAX_EXTENT_SIZE, thus u32 is enough here.
*/
u32 extent_len;
2014-11-06 17:20:58 +08:00
u64 stripe_logical;
u64 stripe_end;
struct btrfs_device *extent_dev;
int extent_mirror_num;
int stop_loop = 0;
physical = map->stripes[num].physical;
offset = 0;
nstripes = div64_u64(length, map->stripe_len);
if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
offset = map->stripe_len * num;
increment = map->stripe_len * map->num_stripes;
mirror_num = 1;
} else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
int factor = map->num_stripes / map->sub_stripes;
offset = map->stripe_len * (num / map->sub_stripes);
increment = map->stripe_len * factor;
mirror_num = num % map->sub_stripes + 1;
} else if (map->type & BTRFS_BLOCK_GROUP_RAID1_MASK) {
increment = map->stripe_len;
mirror_num = num % map->num_stripes + 1;
} else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
increment = map->stripe_len;
mirror_num = num % map->num_stripes + 1;
} else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
2014-11-06 17:20:58 +08:00
get_raid56_logic_offset(physical, num, map, &offset, NULL);
increment = map->stripe_len * nr_data_stripes(map);
mirror_num = 1;
} else {
increment = map->stripe_len;
mirror_num = 1;
}
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
2014-11-06 17:20:58 +08:00
ppath = btrfs_alloc_path();
if (!ppath) {
btrfs_free_path(path);
2014-11-06 17:20:58 +08:00
return -ENOMEM;
}
/*
* work on commit root. The related disk blocks are static as
* long as COW is applied. This means, it is save to rewrite
* them to repair disk errors without any race conditions
*/
path->search_commit_root = 1;
path->skip_locking = 1;
ppath->search_commit_root = 1;
ppath->skip_locking = 1;
/*
* trigger the readahead for extent tree csum tree and wait for
* completion. During readahead, the scrub is officially paused
* to not hold off transaction commits
*/
logical = base + offset;
physical_end = physical + nstripes * map->stripe_len;
if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
get_raid56_logic_offset(physical_end, num,
2014-11-06 17:20:58 +08:00
map, &logic_end, NULL);
logic_end += base;
} else {
logic_end = logical + increment * nstripes;
}
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
wait_event(sctx->list_wait,
atomic_read(&sctx->bios_in_flight) == 0);
scrub_blocked_if_needed(fs_info);
/* FIXME it might be better to start readahead at commit root */
key.objectid = logical;
key.type = BTRFS_EXTENT_ITEM_KEY;
key.offset = (u64)0;
key_end.objectid = logic_end;
key_end.type = BTRFS_METADATA_ITEM_KEY;
key_end.offset = (u64)-1;
reada1 = btrfs_reada_add(root, &key, &key_end);
if (cache->flags & BTRFS_BLOCK_GROUP_DATA) {
key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
key.type = BTRFS_EXTENT_CSUM_KEY;
key.offset = logical;
key_end.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
key_end.type = BTRFS_EXTENT_CSUM_KEY;
key_end.offset = logic_end;
reada2 = btrfs_reada_add(csum_root, &key, &key_end);
} else {
reada2 = NULL;
}
if (!IS_ERR(reada1))
btrfs_reada_wait(reada1);
if (!IS_ERR_OR_NULL(reada2))
btrfs_reada_wait(reada2);
/*
* collect all data csums for the stripe to avoid seeking during
* the scrub. This might currently (crc32) end up to be about 1MB
*/
blk_start_plug(&plug);
if (sctx->is_dev_replace &&
btrfs_dev_is_sequential(sctx->wr_tgtdev, physical)) {
mutex_lock(&sctx->wr_lock);
sctx->write_pointer = physical;
mutex_unlock(&sctx->wr_lock);
sctx->flush_all_writes = true;
}
/*
* now find all extents for each stripe and scrub them
*/
ret = 0;
while (physical < physical_end) {
/*
* canceled?
*/
if (atomic_read(&fs_info->scrub_cancel_req) ||
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
atomic_read(&sctx->cancel_req)) {
ret = -ECANCELED;
goto out;
}
/*
* check to see if we have to pause
*/
if (atomic_read(&fs_info->scrub_pause_req)) {
/* push queued extents */
sctx->flush_all_writes = true;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
scrub_submit(sctx);
mutex_lock(&sctx->wr_lock);
scrub_wr_submit(sctx);
mutex_unlock(&sctx->wr_lock);
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
wait_event(sctx->list_wait,
atomic_read(&sctx->bios_in_flight) == 0);
sctx->flush_all_writes = false;
scrub_blocked_if_needed(fs_info);
}
if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
ret = get_raid56_logic_offset(physical, num, map,
&logical,
&stripe_logical);
logical += base;
if (ret) {
/* it is parity strip */
stripe_logical += base;
stripe_end = stripe_logical + increment;
ret = scrub_raid56_parity(sctx, map, scrub_dev,
ppath, stripe_logical,
stripe_end);
if (ret)
goto out;
goto skip;
}
}
if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
key.type = BTRFS_METADATA_ITEM_KEY;
else
key.type = BTRFS_EXTENT_ITEM_KEY;
key.objectid = logical;
key.offset = (u64)-1;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
goto out;
if (ret > 0) {
ret = btrfs_previous_extent_item(root, path, 0);
if (ret < 0)
goto out;
if (ret > 0) {
/* there's no smaller item, so stick with the
* larger one */
btrfs_release_path(path);
ret = btrfs_search_slot(NULL, root, &key,
path, 0, 0);
if (ret < 0)
goto out;
}
}
stop_loop = 0;
while (1) {
u64 bytes;
l = path->nodes[0];
slot = path->slots[0];
if (slot >= btrfs_header_nritems(l)) {
ret = btrfs_next_leaf(root, path);
if (ret == 0)
continue;
if (ret < 0)
goto out;
stop_loop = 1;
break;
}
btrfs_item_key_to_cpu(l, &key, slot);
if (key.type != BTRFS_EXTENT_ITEM_KEY &&
key.type != BTRFS_METADATA_ITEM_KEY)
goto next;
if (key.type == BTRFS_METADATA_ITEM_KEY)
bytes = fs_info->nodesize;
else
bytes = key.offset;
if (key.objectid + bytes <= logical)
goto next;
if (key.objectid >= logical + map->stripe_len) {
/* out of this device extent */
if (key.objectid >= logic_end)
stop_loop = 1;
break;
}
btrfs: fix a race between scrub and block group removal/allocation When scrub is verifying the extents of a block group for a device, it is possible that the corresponding block group gets removed and its logical address and device extents get used for a new block group allocation. When this happens scrub incorrectly reports that errors were detected and, if the the new block group has a different profile then the old one, deleted block group, we can crash due to a null pointer dereference. Possibly other unexpected and weird consequences can happen as well. Consider the following sequence of actions that leads to the null pointer dereference crash when scrub is running in parallel with balance: 1) Balance sets block group X to read-only mode and starts relocating it. Block group X is a metadata block group, has a raid1 profile (two device extents, each one in a different device) and a logical address of 19424870400; 2) Scrub is running and finds device extent E, which belongs to block group X. It enters scrub_stripe() to find all extents allocated to block group X, the search is done using the extent tree; 3) Balance finishes relocating block group X and removes block group X; 4) Balance starts relocating another block group and when trying to commit the current transaction as part of the preparation step (prepare_to_relocate()), it blocks because scrub is running; 5) The scrub task finds the metadata extent at the logical address 19425001472 and marks the pages of the extent to be read by a bio (struct scrub_bio). The extent item's flags, which have the bit BTRFS_EXTENT_FLAG_TREE_BLOCK set, are added to each page (struct scrub_page). It is these flags in the scrub pages that tells the bio's end io function (scrub_bio_end_io_worker) which type of extent it is dealing with. At this point we end up with 4 pages in a bio which is ready for submission (the metadata extent has a size of 16Kb, so that gives 4 pages on x86); 6) At the next iteration of scrub_stripe(), scrub checks that there is a pause request from the relocation task trying to commit a transaction, therefore it submits the pending bio and pauses, waiting for the transaction commit to complete before resuming; 7) The relocation task commits the transaction. The device extent E, that was used by our block group X, is now available for allocation, since the commit root for the device tree was swapped by the transaction commit; 8) Another task doing a direct IO write allocates a new data block group Y which ends using device extent E. This new block group Y also ends up getting the same logical address that block group X had: 19424870400. This happens because block group X was the block group with the highest logical address and, when allocating Y, find_next_chunk() returns the end offset of the current last block group to be used as the logical address for the new block group, which is 18351128576 + 1073741824 = 19424870400 So our new block group Y has the same logical address and device extent that block group X had. However Y is a data block group, while X was a metadata one, and Y has a raid0 profile, while X had a raid1 profile; 9) After allocating block group Y, the direct IO submits a bio to write to device extent E; 10) The read bio submitted by scrub reads the 4 pages (16Kb) from device extent E, which now correspond to the data written by the task that did a direct IO write. Then at the end io function associated with the bio, scrub_bio_end_io_worker(), we call scrub_block_complete() which calls scrub_checksum(). This later function checks the flags of the first page, and sees that the bit BTRFS_EXTENT_FLAG_TREE_BLOCK is set in the flags, so it assumes it has a metadata extent and then calls scrub_checksum_tree_block(). That functions returns an error, since interpreting data as a metadata extent causes the checksum verification to fail. So this makes scrub_checksum() call scrub_handle_errored_block(), which determines 'failed_mirror_index' to be 1, since the device extent E was allocated as the second mirror of block group X. It allocates BTRFS_MAX_MIRRORS scrub_block structures as an array at 'sblocks_for_recheck', and all the memory is initialized to zeroes by kcalloc(). After that it calls scrub_setup_recheck_block(), which is responsible for filling each of those structures. However, when that function calls btrfs_map_sblock() against the logical address of the metadata extent, 19425001472, it gets a struct btrfs_bio ('bbio') that matches the current block group Y. However block group Y has a raid0 profile and not a raid1 profile like X had, so the following call returns 1: scrub_nr_raid_mirrors(bbio) And as a result scrub_setup_recheck_block() only initializes the first (index 0) scrub_block structure in 'sblocks_for_recheck'. Then scrub_recheck_block() is called by scrub_handle_errored_block() with the second (index 1) scrub_block structure as the argument, because 'failed_mirror_index' was previously set to 1. This scrub_block was not initialized by scrub_setup_recheck_block(), so it has zero pages, its 'page_count' member is 0 and its 'pagev' page array has all members pointing to NULL. Finally when scrub_recheck_block() calls scrub_recheck_block_checksum() we have a NULL pointer dereference when accessing the flags of the first page, as pavev[0] is NULL: static void scrub_recheck_block_checksum(struct scrub_block *sblock) { (...) if (sblock->pagev[0]->flags & BTRFS_EXTENT_FLAG_DATA) scrub_checksum_data(sblock); (...) } Producing a stack trace like the following: [542998.008985] BUG: kernel NULL pointer dereference, address: 0000000000000028 [542998.010238] #PF: supervisor read access in kernel mode [542998.010878] #PF: error_code(0x0000) - not-present page [542998.011516] PGD 0 P4D 0 [542998.011929] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI [542998.012786] CPU: 3 PID: 4846 Comm: kworker/u8:1 Tainted: G B W 5.6.0-rc7-btrfs-next-58 #1 [542998.014524] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 [542998.016065] Workqueue: btrfs-scrub btrfs_work_helper [btrfs] [542998.017255] RIP: 0010:scrub_recheck_block_checksum+0xf/0x20 [btrfs] [542998.018474] Code: 4c 89 e6 ... [542998.021419] RSP: 0018:ffffa7af0375fbd8 EFLAGS: 00010202 [542998.022120] RAX: 0000000000000000 RBX: ffff9792e674d120 RCX: 0000000000000000 [542998.023178] RDX: 0000000000000001 RSI: ffff9792e674d120 RDI: ffff9792e674d120 [542998.024465] RBP: 0000000000000000 R08: 0000000000000067 R09: 0000000000000001 [542998.025462] R10: ffffa7af0375fa50 R11: 0000000000000000 R12: ffff9791f61fe800 [542998.026357] R13: ffff9792e674d120 R14: 0000000000000001 R15: ffffffffc0e3dfc0 [542998.027237] FS: 0000000000000000(0000) GS:ffff9792fb200000(0000) knlGS:0000000000000000 [542998.028327] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [542998.029261] CR2: 0000000000000028 CR3: 00000000b3b18003 CR4: 00000000003606e0 [542998.030301] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [542998.031316] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [542998.032380] Call Trace: [542998.032752] scrub_recheck_block+0x162/0x400 [btrfs] [542998.033500] ? __alloc_pages_nodemask+0x31e/0x460 [542998.034228] scrub_handle_errored_block+0x6f8/0x1920 [btrfs] [542998.035170] scrub_bio_end_io_worker+0x100/0x520 [btrfs] [542998.035991] btrfs_work_helper+0xaa/0x720 [btrfs] [542998.036735] process_one_work+0x26d/0x6a0 [542998.037275] worker_thread+0x4f/0x3e0 [542998.037740] ? process_one_work+0x6a0/0x6a0 [542998.038378] kthread+0x103/0x140 [542998.038789] ? kthread_create_worker_on_cpu+0x70/0x70 [542998.039419] ret_from_fork+0x3a/0x50 [542998.039875] Modules linked in: dm_snapshot dm_thin_pool ... [542998.047288] CR2: 0000000000000028 [542998.047724] ---[ end trace bde186e176c7f96a ]--- This issue has been around for a long time, possibly since scrub exists. The last time I ran into it was over 2 years ago. After recently fixing fstests to pass the "--full-balance" command line option to btrfs-progs when doing balance, several tests started to more heavily exercise balance with fsstress, scrub and other operations in parallel, and therefore started to hit this issue again (with btrfs/061 for example). Fix this by having scrub increment the 'trimming' counter of the block group, which pins the block group in such a way that it guarantees neither its logical address nor device extents can be reused by future block group allocations until we decrement the 'trimming' counter. Also make sure that on each iteration of scrub_stripe() we stop scrubbing the block group if it was removed already. A later patch in the series will rename the block group's 'trimming' counter and its helpers to a more generic name, since now it is not used exclusively for pinning while trimming anymore. CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-08 18:01:10 +08:00
/*
* If our block group was removed in the meanwhile, just
* stop scrubbing since there is no point in continuing.
* Continuing would prevent reusing its device extents
* for new block groups for a long time.
*/
spin_lock(&cache->lock);
if (cache->removed) {
spin_unlock(&cache->lock);
ret = 0;
goto out;
}
spin_unlock(&cache->lock);
extent = btrfs_item_ptr(l, slot,
struct btrfs_extent_item);
flags = btrfs_extent_flags(l, extent);
generation = btrfs_extent_generation(l, extent);
btrfs: Fix scrub panic when leaf crosses stripes Scrub panic in following operation: mkfs.ext4 /dev/vdh btrfs-convert /dev/vdh mount /dev/vdh /mnt/tmp1 btrfs scrub start -B /dev/vdh (panic) Reason: 1: In some case, leaf created by btrfs-convert was splited into 2 strips. 2: Scrub bypassed part of above wrong leaf data, but remain data caused panic in scrub_checksum_tree_block(). For reason 1: we can get following information after some simple operation. a. mkfs.ext4 /dev/vdh btrfs-convert /dev/vdh b. btrfs-debug-tree /dev/vdh we can see following item in extent tree: item 25 key (27054080 METADATA_ITEM 0) itemoff 15083 itemsize 33 Its logical address is [27054080, 27070464) and acrossed 2 strips: [27000832, 27066368) [27066368, 27131904) Will be fixed in btrfs-progs(btrfs-convert, btrfsck, ...) For reason 2: Scrub is trying to do a "bypass" in this case, but the result is "panic", because current code lacks of some condition in bypass, and let some wrong leaf data escaped. This patch fixed above scrub code. Before patch: # btrfs scrub start -B /dev/vdh (panic) After patch: # btrfs scrub start -B /dev/vdh scrub done for 353cec8f-da31-4a94-aa35-be72d997b06e ... # dmesg ... [ 59.088697] BTRFS error (device vdh): scrub: tree block 27054080 spanning stripes, ignored. logical=27000832 [ 59.089929] BTRFS error (device vdh): scrub: tree block 27054080 spanning stripes, ignored. logical=27066368 # Reported-by: Chris Murphy <lists@colorremedies.com> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-07-23 12:29:49 +08:00
if ((flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) &&
(key.objectid < logical ||
key.objectid + bytes >
logical + map->stripe_len)) {
btrfs_err(fs_info,
"scrub: tree block %llu spanning stripes, ignored. logical=%llu",
key.objectid, logical);
spin_lock(&sctx->stat_lock);
sctx->stat.uncorrectable_errors++;
spin_unlock(&sctx->stat_lock);
goto next;
}
again:
extent_logical = key.objectid;
ASSERT(bytes <= U32_MAX);
extent_len = bytes;
/*
* trim extent to this stripe
*/
if (extent_logical < logical) {
extent_len -= logical - extent_logical;
extent_logical = logical;
}
if (extent_logical + extent_len >
logical + map->stripe_len) {
extent_len = logical + map->stripe_len -
extent_logical;
}
extent_physical = extent_logical - logical + physical;
extent_dev = scrub_dev;
extent_mirror_num = mirror_num;
if (sctx->is_dev_replace)
scrub_remap_extent(fs_info, extent_logical,
extent_len, &extent_physical,
&extent_dev,
&extent_mirror_num);
if (flags & BTRFS_EXTENT_FLAG_DATA) {
ret = btrfs_lookup_csums_range(csum_root,
extent_logical,
extent_logical + extent_len - 1,
&sctx->csum_list, 1);
if (ret)
goto out;
}
ret = scrub_extent(sctx, map, extent_logical, extent_len,
extent_physical, extent_dev, flags,
generation, extent_mirror_num,
extent_logical - logical + physical);
scrub_free_csums(sctx);
if (ret)
goto out;
if (sctx->is_dev_replace)
sync_replace_for_zoned(sctx);
if (extent_logical + extent_len <
key.objectid + bytes) {
if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
/*
* loop until we find next data stripe
* or we have finished all stripes.
*/
2014-11-06 17:20:58 +08:00
loop:
physical += map->stripe_len;
ret = get_raid56_logic_offset(physical,
num, map, &logical,
&stripe_logical);
logical += base;
if (ret && physical < physical_end) {
stripe_logical += base;
stripe_end = stripe_logical +
increment;
2014-11-06 17:20:58 +08:00
ret = scrub_raid56_parity(sctx,
map, scrub_dev, ppath,
stripe_logical,
stripe_end);
if (ret)
goto out;
goto loop;
}
} else {
physical += map->stripe_len;
logical += increment;
}
if (logical < key.objectid + bytes) {
cond_resched();
goto again;
}
if (physical >= physical_end) {
stop_loop = 1;
break;
}
}
next:
path->slots[0]++;
}
btrfs_release_path(path);
skip:
logical += increment;
physical += map->stripe_len;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
spin_lock(&sctx->stat_lock);
if (stop_loop)
sctx->stat.last_physical = map->stripes[num].physical +
length;
else
sctx->stat.last_physical = physical;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
spin_unlock(&sctx->stat_lock);
if (stop_loop)
break;
}
out:
/* push queued extents */
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
scrub_submit(sctx);
mutex_lock(&sctx->wr_lock);
scrub_wr_submit(sctx);
mutex_unlock(&sctx->wr_lock);
blk_finish_plug(&plug);
btrfs_free_path(path);
2014-11-06 17:20:58 +08:00
btrfs_free_path(ppath);
if (sctx->is_dev_replace && ret >= 0) {
int ret2;
ret2 = sync_write_pointer_for_zoned(sctx, base + offset,
map->stripes[num].physical,
physical_end);
if (ret2)
ret = ret2;
}
return ret < 0 ? ret : 0;
}
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
static noinline_for_stack int scrub_chunk(struct scrub_ctx *sctx,
struct btrfs_device *scrub_dev,
u64 chunk_offset, u64 length,
u64 dev_offset,
struct btrfs_block_group *cache)
{
struct btrfs_fs_info *fs_info = sctx->fs_info;
struct extent_map_tree *map_tree = &fs_info->mapping_tree;
struct map_lookup *map;
struct extent_map *em;
int i;
int ret = 0;
read_lock(&map_tree->lock);
em = lookup_extent_mapping(map_tree, chunk_offset, 1);
read_unlock(&map_tree->lock);
if (!em) {
/*
* Might have been an unused block group deleted by the cleaner
* kthread or relocation.
*/
spin_lock(&cache->lock);
if (!cache->removed)
ret = -EINVAL;
spin_unlock(&cache->lock);
return ret;
}
map = em->map_lookup;
if (em->start != chunk_offset)
goto out;
if (em->len < length)
goto out;
for (i = 0; i < map->num_stripes; ++i) {
if (map->stripes[i].dev->bdev == scrub_dev->bdev &&
map->stripes[i].physical == dev_offset) {
ret = scrub_stripe(sctx, map, scrub_dev, i,
btrfs: fix a race between scrub and block group removal/allocation When scrub is verifying the extents of a block group for a device, it is possible that the corresponding block group gets removed and its logical address and device extents get used for a new block group allocation. When this happens scrub incorrectly reports that errors were detected and, if the the new block group has a different profile then the old one, deleted block group, we can crash due to a null pointer dereference. Possibly other unexpected and weird consequences can happen as well. Consider the following sequence of actions that leads to the null pointer dereference crash when scrub is running in parallel with balance: 1) Balance sets block group X to read-only mode and starts relocating it. Block group X is a metadata block group, has a raid1 profile (two device extents, each one in a different device) and a logical address of 19424870400; 2) Scrub is running and finds device extent E, which belongs to block group X. It enters scrub_stripe() to find all extents allocated to block group X, the search is done using the extent tree; 3) Balance finishes relocating block group X and removes block group X; 4) Balance starts relocating another block group and when trying to commit the current transaction as part of the preparation step (prepare_to_relocate()), it blocks because scrub is running; 5) The scrub task finds the metadata extent at the logical address 19425001472 and marks the pages of the extent to be read by a bio (struct scrub_bio). The extent item's flags, which have the bit BTRFS_EXTENT_FLAG_TREE_BLOCK set, are added to each page (struct scrub_page). It is these flags in the scrub pages that tells the bio's end io function (scrub_bio_end_io_worker) which type of extent it is dealing with. At this point we end up with 4 pages in a bio which is ready for submission (the metadata extent has a size of 16Kb, so that gives 4 pages on x86); 6) At the next iteration of scrub_stripe(), scrub checks that there is a pause request from the relocation task trying to commit a transaction, therefore it submits the pending bio and pauses, waiting for the transaction commit to complete before resuming; 7) The relocation task commits the transaction. The device extent E, that was used by our block group X, is now available for allocation, since the commit root for the device tree was swapped by the transaction commit; 8) Another task doing a direct IO write allocates a new data block group Y which ends using device extent E. This new block group Y also ends up getting the same logical address that block group X had: 19424870400. This happens because block group X was the block group with the highest logical address and, when allocating Y, find_next_chunk() returns the end offset of the current last block group to be used as the logical address for the new block group, which is 18351128576 + 1073741824 = 19424870400 So our new block group Y has the same logical address and device extent that block group X had. However Y is a data block group, while X was a metadata one, and Y has a raid0 profile, while X had a raid1 profile; 9) After allocating block group Y, the direct IO submits a bio to write to device extent E; 10) The read bio submitted by scrub reads the 4 pages (16Kb) from device extent E, which now correspond to the data written by the task that did a direct IO write. Then at the end io function associated with the bio, scrub_bio_end_io_worker(), we call scrub_block_complete() which calls scrub_checksum(). This later function checks the flags of the first page, and sees that the bit BTRFS_EXTENT_FLAG_TREE_BLOCK is set in the flags, so it assumes it has a metadata extent and then calls scrub_checksum_tree_block(). That functions returns an error, since interpreting data as a metadata extent causes the checksum verification to fail. So this makes scrub_checksum() call scrub_handle_errored_block(), which determines 'failed_mirror_index' to be 1, since the device extent E was allocated as the second mirror of block group X. It allocates BTRFS_MAX_MIRRORS scrub_block structures as an array at 'sblocks_for_recheck', and all the memory is initialized to zeroes by kcalloc(). After that it calls scrub_setup_recheck_block(), which is responsible for filling each of those structures. However, when that function calls btrfs_map_sblock() against the logical address of the metadata extent, 19425001472, it gets a struct btrfs_bio ('bbio') that matches the current block group Y. However block group Y has a raid0 profile and not a raid1 profile like X had, so the following call returns 1: scrub_nr_raid_mirrors(bbio) And as a result scrub_setup_recheck_block() only initializes the first (index 0) scrub_block structure in 'sblocks_for_recheck'. Then scrub_recheck_block() is called by scrub_handle_errored_block() with the second (index 1) scrub_block structure as the argument, because 'failed_mirror_index' was previously set to 1. This scrub_block was not initialized by scrub_setup_recheck_block(), so it has zero pages, its 'page_count' member is 0 and its 'pagev' page array has all members pointing to NULL. Finally when scrub_recheck_block() calls scrub_recheck_block_checksum() we have a NULL pointer dereference when accessing the flags of the first page, as pavev[0] is NULL: static void scrub_recheck_block_checksum(struct scrub_block *sblock) { (...) if (sblock->pagev[0]->flags & BTRFS_EXTENT_FLAG_DATA) scrub_checksum_data(sblock); (...) } Producing a stack trace like the following: [542998.008985] BUG: kernel NULL pointer dereference, address: 0000000000000028 [542998.010238] #PF: supervisor read access in kernel mode [542998.010878] #PF: error_code(0x0000) - not-present page [542998.011516] PGD 0 P4D 0 [542998.011929] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI [542998.012786] CPU: 3 PID: 4846 Comm: kworker/u8:1 Tainted: G B W 5.6.0-rc7-btrfs-next-58 #1 [542998.014524] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 [542998.016065] Workqueue: btrfs-scrub btrfs_work_helper [btrfs] [542998.017255] RIP: 0010:scrub_recheck_block_checksum+0xf/0x20 [btrfs] [542998.018474] Code: 4c 89 e6 ... [542998.021419] RSP: 0018:ffffa7af0375fbd8 EFLAGS: 00010202 [542998.022120] RAX: 0000000000000000 RBX: ffff9792e674d120 RCX: 0000000000000000 [542998.023178] RDX: 0000000000000001 RSI: ffff9792e674d120 RDI: ffff9792e674d120 [542998.024465] RBP: 0000000000000000 R08: 0000000000000067 R09: 0000000000000001 [542998.025462] R10: ffffa7af0375fa50 R11: 0000000000000000 R12: ffff9791f61fe800 [542998.026357] R13: ffff9792e674d120 R14: 0000000000000001 R15: ffffffffc0e3dfc0 [542998.027237] FS: 0000000000000000(0000) GS:ffff9792fb200000(0000) knlGS:0000000000000000 [542998.028327] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [542998.029261] CR2: 0000000000000028 CR3: 00000000b3b18003 CR4: 00000000003606e0 [542998.030301] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [542998.031316] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [542998.032380] Call Trace: [542998.032752] scrub_recheck_block+0x162/0x400 [btrfs] [542998.033500] ? __alloc_pages_nodemask+0x31e/0x460 [542998.034228] scrub_handle_errored_block+0x6f8/0x1920 [btrfs] [542998.035170] scrub_bio_end_io_worker+0x100/0x520 [btrfs] [542998.035991] btrfs_work_helper+0xaa/0x720 [btrfs] [542998.036735] process_one_work+0x26d/0x6a0 [542998.037275] worker_thread+0x4f/0x3e0 [542998.037740] ? process_one_work+0x6a0/0x6a0 [542998.038378] kthread+0x103/0x140 [542998.038789] ? kthread_create_worker_on_cpu+0x70/0x70 [542998.039419] ret_from_fork+0x3a/0x50 [542998.039875] Modules linked in: dm_snapshot dm_thin_pool ... [542998.047288] CR2: 0000000000000028 [542998.047724] ---[ end trace bde186e176c7f96a ]--- This issue has been around for a long time, possibly since scrub exists. The last time I ran into it was over 2 years ago. After recently fixing fstests to pass the "--full-balance" command line option to btrfs-progs when doing balance, several tests started to more heavily exercise balance with fsstress, scrub and other operations in parallel, and therefore started to hit this issue again (with btrfs/061 for example). Fix this by having scrub increment the 'trimming' counter of the block group, which pins the block group in such a way that it guarantees neither its logical address nor device extents can be reused by future block group allocations until we decrement the 'trimming' counter. Also make sure that on each iteration of scrub_stripe() we stop scrubbing the block group if it was removed already. A later patch in the series will rename the block group's 'trimming' counter and its helpers to a more generic name, since now it is not used exclusively for pinning while trimming anymore. CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-08 18:01:10 +08:00
chunk_offset, length, cache);
if (ret)
goto out;
}
}
out:
free_extent_map(em);
return ret;
}
static int finish_extent_writes_for_zoned(struct btrfs_root *root,
struct btrfs_block_group *cache)
{
struct btrfs_fs_info *fs_info = cache->fs_info;
struct btrfs_trans_handle *trans;
if (!btrfs_is_zoned(fs_info))
return 0;
btrfs_wait_block_group_reservations(cache);
btrfs_wait_nocow_writers(cache);
btrfs_wait_ordered_roots(fs_info, U64_MAX, cache->start, cache->length);
trans = btrfs_join_transaction(root);
if (IS_ERR(trans))
return PTR_ERR(trans);
return btrfs_commit_transaction(trans);
}
static noinline_for_stack
int scrub_enumerate_chunks(struct scrub_ctx *sctx,
struct btrfs_device *scrub_dev, u64 start, u64 end)
{
struct btrfs_dev_extent *dev_extent = NULL;
struct btrfs_path *path;
struct btrfs_fs_info *fs_info = sctx->fs_info;
struct btrfs_root *root = fs_info->dev_root;
u64 length;
u64 chunk_offset;
int ret = 0;
btrfs: Continue replace when set_block_ro failed xfstests/011 failed in node with small_size filesystem. Can be reproduced by following script: DEV_LIST="/dev/vdd /dev/vde" DEV_REPLACE="/dev/vdf" do_test() { local mkfs_opt="$1" local size="$2" dmesg -c >/dev/null umount $SCRATCH_MNT &>/dev/null echo mkfs.btrfs -f $mkfs_opt "${DEV_LIST[*]}" mkfs.btrfs -f $mkfs_opt "${DEV_LIST[@]}" || return 1 mount "${DEV_LIST[0]}" $SCRATCH_MNT echo -n "Writing big files" dd if=/dev/urandom of=$SCRATCH_MNT/t0 bs=1M count=1 >/dev/null 2>&1 for ((i = 1; i <= size; i++)); do echo -n . /bin/cp $SCRATCH_MNT/t0 $SCRATCH_MNT/t$i || return 1 done echo echo Start replace btrfs replace start -Bf "${DEV_LIST[0]}" "$DEV_REPLACE" $SCRATCH_MNT || { dmesg return 1 } return 0 } # Set size to value near fs size # for example, 1897 can trigger this bug in 2.6G device. # ./do_test "-d raid1 -m raid1" 1897 System will report replace fail with following warning in dmesg: [ 134.710853] BTRFS: dev_replace from /dev/vdd (devid 1) to /dev/vdf started [ 135.542390] BTRFS: btrfs_scrub_dev(/dev/vdd, 1, /dev/vdf) failed -28 [ 135.543505] ------------[ cut here ]------------ [ 135.544127] WARNING: CPU: 0 PID: 4080 at fs/btrfs/dev-replace.c:428 btrfs_dev_replace_start+0x398/0x440() [ 135.545276] Modules linked in: [ 135.545681] CPU: 0 PID: 4080 Comm: btrfs Not tainted 4.3.0 #256 [ 135.546439] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.2-0-g33fbe13 by qemu-project.org 04/01/2014 [ 135.547798] ffffffff81c5bfcf ffff88003cbb3d28 ffffffff817fe7b5 0000000000000000 [ 135.548774] ffff88003cbb3d60 ffffffff810a88f1 ffff88002b030000 00000000ffffffe4 [ 135.549774] ffff88003c080000 ffff88003c082588 ffff88003c28ab60 ffff88003cbb3d70 [ 135.550758] Call Trace: [ 135.551086] [<ffffffff817fe7b5>] dump_stack+0x44/0x55 [ 135.551737] [<ffffffff810a88f1>] warn_slowpath_common+0x81/0xc0 [ 135.552487] [<ffffffff810a89e5>] warn_slowpath_null+0x15/0x20 [ 135.553211] [<ffffffff81448c88>] btrfs_dev_replace_start+0x398/0x440 [ 135.554051] [<ffffffff81412c3e>] btrfs_ioctl+0x1d2e/0x25c0 [ 135.554722] [<ffffffff8114c7ba>] ? __audit_syscall_entry+0xaa/0xf0 [ 135.555506] [<ffffffff8111ab36>] ? current_kernel_time64+0x56/0xa0 [ 135.556304] [<ffffffff81201e3d>] do_vfs_ioctl+0x30d/0x580 [ 135.557009] [<ffffffff8114c7ba>] ? __audit_syscall_entry+0xaa/0xf0 [ 135.557855] [<ffffffff810011d1>] ? do_audit_syscall_entry+0x61/0x70 [ 135.558669] [<ffffffff8120d1c1>] ? __fget_light+0x61/0x90 [ 135.559374] [<ffffffff81202124>] SyS_ioctl+0x74/0x80 [ 135.559987] [<ffffffff81809857>] entry_SYSCALL_64_fastpath+0x12/0x6f [ 135.560842] ---[ end trace 2a5c1fc3205abbdd ]--- Reason: When big data writen to fs, the whole free space will be allocated for data chunk. And operation as scrub need to set_block_ro(), and when there is only one metadata chunk in system(or other metadata chunks are all full), the function will try to allocate a new chunk, and failed because no space in device. Fix: When set_block_ro failed for metadata chunk, it is not a problem because scrub_lock paused commit_trancaction in same time, and metadata are always cowed, so the on-the-fly writepages will not write data into same place with scrub/replace. Let replace continue in this case is no problem. Tested by above script, and xfstests/011, plus 100 times xfstests/070. Changelog v1->v2: 1: Add detail comments in source and commit-message. 2: Add dmesg detail into commit-message. 3: Limit return value of -ENOSPC to be passed. All suggested by: Filipe Manana <fdmanana@gmail.com> Suggested-by: Filipe Manana <fdmanana@gmail.com> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-11-17 18:46:17 +08:00
int ro_set;
int slot;
struct extent_buffer *l;
struct btrfs_key key;
struct btrfs_key found_key;
struct btrfs_block_group *cache;
struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->reada = READA_FORWARD;
path->search_commit_root = 1;
path->skip_locking = 1;
key.objectid = scrub_dev->devid;
key.offset = 0ull;
key.type = BTRFS_DEV_EXTENT_KEY;
while (1) {
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
break;
if (ret > 0) {
if (path->slots[0] >=
btrfs_header_nritems(path->nodes[0])) {
ret = btrfs_next_leaf(root, path);
if (ret < 0)
break;
if (ret > 0) {
ret = 0;
break;
}
} else {
ret = 0;
}
}
l = path->nodes[0];
slot = path->slots[0];
btrfs_item_key_to_cpu(l, &found_key, slot);
if (found_key.objectid != scrub_dev->devid)
break;
if (found_key.type != BTRFS_DEV_EXTENT_KEY)
break;
if (found_key.offset >= end)
break;
if (found_key.offset < key.offset)
break;
dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
length = btrfs_dev_extent_length(l, dev_extent);
if (found_key.offset + length <= start)
goto skip;
chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
/*
* get a reference on the corresponding block group to prevent
* the chunk from going away while we scrub it
*/
cache = btrfs_lookup_block_group(fs_info, chunk_offset);
/* some chunks are removed but not committed to disk yet,
* continue scrubbing */
if (!cache)
goto skip;
btrfs: zoned: mark block groups to copy for device-replace This is the 1/4 patch to support device-replace on zoned filesystems. We have two types of IOs during the device replace process. One is an IO to "copy" (by the scrub functions) all the device extents from the source device to the destination device. The other one is an IO to "clone" (by handle_ops_on_dev_replace()) new incoming write IOs from users to the source device into the target device. Cloning incoming IOs can break the sequential write rule in on target device. When a write is mapped in the middle of a block group, the IO is directed to the middle of a target device zone, which breaks the sequential write requirement. However, the cloning function cannot be disabled since incoming IOs targeting already copied device extents must be cloned so that the IO is executed on the target device. We cannot use dev_replace->cursor_{left,right} to determine whether a bio is going to a not yet copied region. Since we have a time gap between finishing btrfs_scrub_dev() and rewriting the mapping tree in btrfs_dev_replace_finishing(), we can have a newly allocated device extent which is never cloned nor copied. So the point is to copy only already existing device extents. This patch introduces mark_block_group_to_copy() to mark existing block groups as a target of copying. Then, handle_ops_on_dev_replace() and dev-replace can check the flag to do their job. Also, btrfs_finish_block_group_to_copy() will check if the copied stripe is the last stripe in the block group. With the last stripe copied, the to_copy flag is finally disabled. Afterwards we can safely clone incoming IOs on this block group. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-04 18:22:11 +08:00
if (sctx->is_dev_replace && btrfs_is_zoned(fs_info)) {
spin_lock(&cache->lock);
if (!cache->to_copy) {
spin_unlock(&cache->lock);
btrfs_put_block_group(cache);
goto skip;
btrfs: zoned: mark block groups to copy for device-replace This is the 1/4 patch to support device-replace on zoned filesystems. We have two types of IOs during the device replace process. One is an IO to "copy" (by the scrub functions) all the device extents from the source device to the destination device. The other one is an IO to "clone" (by handle_ops_on_dev_replace()) new incoming write IOs from users to the source device into the target device. Cloning incoming IOs can break the sequential write rule in on target device. When a write is mapped in the middle of a block group, the IO is directed to the middle of a target device zone, which breaks the sequential write requirement. However, the cloning function cannot be disabled since incoming IOs targeting already copied device extents must be cloned so that the IO is executed on the target device. We cannot use dev_replace->cursor_{left,right} to determine whether a bio is going to a not yet copied region. Since we have a time gap between finishing btrfs_scrub_dev() and rewriting the mapping tree in btrfs_dev_replace_finishing(), we can have a newly allocated device extent which is never cloned nor copied. So the point is to copy only already existing device extents. This patch introduces mark_block_group_to_copy() to mark existing block groups as a target of copying. Then, handle_ops_on_dev_replace() and dev-replace can check the flag to do their job. Also, btrfs_finish_block_group_to_copy() will check if the copied stripe is the last stripe in the block group. With the last stripe copied, the to_copy flag is finally disabled. Afterwards we can safely clone incoming IOs on this block group. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-04 18:22:11 +08:00
}
spin_unlock(&cache->lock);
}
btrfs: fix a race between scrub and block group removal/allocation When scrub is verifying the extents of a block group for a device, it is possible that the corresponding block group gets removed and its logical address and device extents get used for a new block group allocation. When this happens scrub incorrectly reports that errors were detected and, if the the new block group has a different profile then the old one, deleted block group, we can crash due to a null pointer dereference. Possibly other unexpected and weird consequences can happen as well. Consider the following sequence of actions that leads to the null pointer dereference crash when scrub is running in parallel with balance: 1) Balance sets block group X to read-only mode and starts relocating it. Block group X is a metadata block group, has a raid1 profile (two device extents, each one in a different device) and a logical address of 19424870400; 2) Scrub is running and finds device extent E, which belongs to block group X. It enters scrub_stripe() to find all extents allocated to block group X, the search is done using the extent tree; 3) Balance finishes relocating block group X and removes block group X; 4) Balance starts relocating another block group and when trying to commit the current transaction as part of the preparation step (prepare_to_relocate()), it blocks because scrub is running; 5) The scrub task finds the metadata extent at the logical address 19425001472 and marks the pages of the extent to be read by a bio (struct scrub_bio). The extent item's flags, which have the bit BTRFS_EXTENT_FLAG_TREE_BLOCK set, are added to each page (struct scrub_page). It is these flags in the scrub pages that tells the bio's end io function (scrub_bio_end_io_worker) which type of extent it is dealing with. At this point we end up with 4 pages in a bio which is ready for submission (the metadata extent has a size of 16Kb, so that gives 4 pages on x86); 6) At the next iteration of scrub_stripe(), scrub checks that there is a pause request from the relocation task trying to commit a transaction, therefore it submits the pending bio and pauses, waiting for the transaction commit to complete before resuming; 7) The relocation task commits the transaction. The device extent E, that was used by our block group X, is now available for allocation, since the commit root for the device tree was swapped by the transaction commit; 8) Another task doing a direct IO write allocates a new data block group Y which ends using device extent E. This new block group Y also ends up getting the same logical address that block group X had: 19424870400. This happens because block group X was the block group with the highest logical address and, when allocating Y, find_next_chunk() returns the end offset of the current last block group to be used as the logical address for the new block group, which is 18351128576 + 1073741824 = 19424870400 So our new block group Y has the same logical address and device extent that block group X had. However Y is a data block group, while X was a metadata one, and Y has a raid0 profile, while X had a raid1 profile; 9) After allocating block group Y, the direct IO submits a bio to write to device extent E; 10) The read bio submitted by scrub reads the 4 pages (16Kb) from device extent E, which now correspond to the data written by the task that did a direct IO write. Then at the end io function associated with the bio, scrub_bio_end_io_worker(), we call scrub_block_complete() which calls scrub_checksum(). This later function checks the flags of the first page, and sees that the bit BTRFS_EXTENT_FLAG_TREE_BLOCK is set in the flags, so it assumes it has a metadata extent and then calls scrub_checksum_tree_block(). That functions returns an error, since interpreting data as a metadata extent causes the checksum verification to fail. So this makes scrub_checksum() call scrub_handle_errored_block(), which determines 'failed_mirror_index' to be 1, since the device extent E was allocated as the second mirror of block group X. It allocates BTRFS_MAX_MIRRORS scrub_block structures as an array at 'sblocks_for_recheck', and all the memory is initialized to zeroes by kcalloc(). After that it calls scrub_setup_recheck_block(), which is responsible for filling each of those structures. However, when that function calls btrfs_map_sblock() against the logical address of the metadata extent, 19425001472, it gets a struct btrfs_bio ('bbio') that matches the current block group Y. However block group Y has a raid0 profile and not a raid1 profile like X had, so the following call returns 1: scrub_nr_raid_mirrors(bbio) And as a result scrub_setup_recheck_block() only initializes the first (index 0) scrub_block structure in 'sblocks_for_recheck'. Then scrub_recheck_block() is called by scrub_handle_errored_block() with the second (index 1) scrub_block structure as the argument, because 'failed_mirror_index' was previously set to 1. This scrub_block was not initialized by scrub_setup_recheck_block(), so it has zero pages, its 'page_count' member is 0 and its 'pagev' page array has all members pointing to NULL. Finally when scrub_recheck_block() calls scrub_recheck_block_checksum() we have a NULL pointer dereference when accessing the flags of the first page, as pavev[0] is NULL: static void scrub_recheck_block_checksum(struct scrub_block *sblock) { (...) if (sblock->pagev[0]->flags & BTRFS_EXTENT_FLAG_DATA) scrub_checksum_data(sblock); (...) } Producing a stack trace like the following: [542998.008985] BUG: kernel NULL pointer dereference, address: 0000000000000028 [542998.010238] #PF: supervisor read access in kernel mode [542998.010878] #PF: error_code(0x0000) - not-present page [542998.011516] PGD 0 P4D 0 [542998.011929] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI [542998.012786] CPU: 3 PID: 4846 Comm: kworker/u8:1 Tainted: G B W 5.6.0-rc7-btrfs-next-58 #1 [542998.014524] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 [542998.016065] Workqueue: btrfs-scrub btrfs_work_helper [btrfs] [542998.017255] RIP: 0010:scrub_recheck_block_checksum+0xf/0x20 [btrfs] [542998.018474] Code: 4c 89 e6 ... [542998.021419] RSP: 0018:ffffa7af0375fbd8 EFLAGS: 00010202 [542998.022120] RAX: 0000000000000000 RBX: ffff9792e674d120 RCX: 0000000000000000 [542998.023178] RDX: 0000000000000001 RSI: ffff9792e674d120 RDI: ffff9792e674d120 [542998.024465] RBP: 0000000000000000 R08: 0000000000000067 R09: 0000000000000001 [542998.025462] R10: ffffa7af0375fa50 R11: 0000000000000000 R12: ffff9791f61fe800 [542998.026357] R13: ffff9792e674d120 R14: 0000000000000001 R15: ffffffffc0e3dfc0 [542998.027237] FS: 0000000000000000(0000) GS:ffff9792fb200000(0000) knlGS:0000000000000000 [542998.028327] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [542998.029261] CR2: 0000000000000028 CR3: 00000000b3b18003 CR4: 00000000003606e0 [542998.030301] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [542998.031316] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [542998.032380] Call Trace: [542998.032752] scrub_recheck_block+0x162/0x400 [btrfs] [542998.033500] ? __alloc_pages_nodemask+0x31e/0x460 [542998.034228] scrub_handle_errored_block+0x6f8/0x1920 [btrfs] [542998.035170] scrub_bio_end_io_worker+0x100/0x520 [btrfs] [542998.035991] btrfs_work_helper+0xaa/0x720 [btrfs] [542998.036735] process_one_work+0x26d/0x6a0 [542998.037275] worker_thread+0x4f/0x3e0 [542998.037740] ? process_one_work+0x6a0/0x6a0 [542998.038378] kthread+0x103/0x140 [542998.038789] ? kthread_create_worker_on_cpu+0x70/0x70 [542998.039419] ret_from_fork+0x3a/0x50 [542998.039875] Modules linked in: dm_snapshot dm_thin_pool ... [542998.047288] CR2: 0000000000000028 [542998.047724] ---[ end trace bde186e176c7f96a ]--- This issue has been around for a long time, possibly since scrub exists. The last time I ran into it was over 2 years ago. After recently fixing fstests to pass the "--full-balance" command line option to btrfs-progs when doing balance, several tests started to more heavily exercise balance with fsstress, scrub and other operations in parallel, and therefore started to hit this issue again (with btrfs/061 for example). Fix this by having scrub increment the 'trimming' counter of the block group, which pins the block group in such a way that it guarantees neither its logical address nor device extents can be reused by future block group allocations until we decrement the 'trimming' counter. Also make sure that on each iteration of scrub_stripe() we stop scrubbing the block group if it was removed already. A later patch in the series will rename the block group's 'trimming' counter and its helpers to a more generic name, since now it is not used exclusively for pinning while trimming anymore. CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-08 18:01:10 +08:00
/*
* Make sure that while we are scrubbing the corresponding block
* group doesn't get its logical address and its device extents
* reused for another block group, which can possibly be of a
* different type and different profile. We do this to prevent
* false error detections and crashes due to bogus attempts to
* repair extents.
*/
spin_lock(&cache->lock);
if (cache->removed) {
spin_unlock(&cache->lock);
btrfs_put_block_group(cache);
goto skip;
}
btrfs_freeze_block_group(cache);
btrfs: fix a race between scrub and block group removal/allocation When scrub is verifying the extents of a block group for a device, it is possible that the corresponding block group gets removed and its logical address and device extents get used for a new block group allocation. When this happens scrub incorrectly reports that errors were detected and, if the the new block group has a different profile then the old one, deleted block group, we can crash due to a null pointer dereference. Possibly other unexpected and weird consequences can happen as well. Consider the following sequence of actions that leads to the null pointer dereference crash when scrub is running in parallel with balance: 1) Balance sets block group X to read-only mode and starts relocating it. Block group X is a metadata block group, has a raid1 profile (two device extents, each one in a different device) and a logical address of 19424870400; 2) Scrub is running and finds device extent E, which belongs to block group X. It enters scrub_stripe() to find all extents allocated to block group X, the search is done using the extent tree; 3) Balance finishes relocating block group X and removes block group X; 4) Balance starts relocating another block group and when trying to commit the current transaction as part of the preparation step (prepare_to_relocate()), it blocks because scrub is running; 5) The scrub task finds the metadata extent at the logical address 19425001472 and marks the pages of the extent to be read by a bio (struct scrub_bio). The extent item's flags, which have the bit BTRFS_EXTENT_FLAG_TREE_BLOCK set, are added to each page (struct scrub_page). It is these flags in the scrub pages that tells the bio's end io function (scrub_bio_end_io_worker) which type of extent it is dealing with. At this point we end up with 4 pages in a bio which is ready for submission (the metadata extent has a size of 16Kb, so that gives 4 pages on x86); 6) At the next iteration of scrub_stripe(), scrub checks that there is a pause request from the relocation task trying to commit a transaction, therefore it submits the pending bio and pauses, waiting for the transaction commit to complete before resuming; 7) The relocation task commits the transaction. The device extent E, that was used by our block group X, is now available for allocation, since the commit root for the device tree was swapped by the transaction commit; 8) Another task doing a direct IO write allocates a new data block group Y which ends using device extent E. This new block group Y also ends up getting the same logical address that block group X had: 19424870400. This happens because block group X was the block group with the highest logical address and, when allocating Y, find_next_chunk() returns the end offset of the current last block group to be used as the logical address for the new block group, which is 18351128576 + 1073741824 = 19424870400 So our new block group Y has the same logical address and device extent that block group X had. However Y is a data block group, while X was a metadata one, and Y has a raid0 profile, while X had a raid1 profile; 9) After allocating block group Y, the direct IO submits a bio to write to device extent E; 10) The read bio submitted by scrub reads the 4 pages (16Kb) from device extent E, which now correspond to the data written by the task that did a direct IO write. Then at the end io function associated with the bio, scrub_bio_end_io_worker(), we call scrub_block_complete() which calls scrub_checksum(). This later function checks the flags of the first page, and sees that the bit BTRFS_EXTENT_FLAG_TREE_BLOCK is set in the flags, so it assumes it has a metadata extent and then calls scrub_checksum_tree_block(). That functions returns an error, since interpreting data as a metadata extent causes the checksum verification to fail. So this makes scrub_checksum() call scrub_handle_errored_block(), which determines 'failed_mirror_index' to be 1, since the device extent E was allocated as the second mirror of block group X. It allocates BTRFS_MAX_MIRRORS scrub_block structures as an array at 'sblocks_for_recheck', and all the memory is initialized to zeroes by kcalloc(). After that it calls scrub_setup_recheck_block(), which is responsible for filling each of those structures. However, when that function calls btrfs_map_sblock() against the logical address of the metadata extent, 19425001472, it gets a struct btrfs_bio ('bbio') that matches the current block group Y. However block group Y has a raid0 profile and not a raid1 profile like X had, so the following call returns 1: scrub_nr_raid_mirrors(bbio) And as a result scrub_setup_recheck_block() only initializes the first (index 0) scrub_block structure in 'sblocks_for_recheck'. Then scrub_recheck_block() is called by scrub_handle_errored_block() with the second (index 1) scrub_block structure as the argument, because 'failed_mirror_index' was previously set to 1. This scrub_block was not initialized by scrub_setup_recheck_block(), so it has zero pages, its 'page_count' member is 0 and its 'pagev' page array has all members pointing to NULL. Finally when scrub_recheck_block() calls scrub_recheck_block_checksum() we have a NULL pointer dereference when accessing the flags of the first page, as pavev[0] is NULL: static void scrub_recheck_block_checksum(struct scrub_block *sblock) { (...) if (sblock->pagev[0]->flags & BTRFS_EXTENT_FLAG_DATA) scrub_checksum_data(sblock); (...) } Producing a stack trace like the following: [542998.008985] BUG: kernel NULL pointer dereference, address: 0000000000000028 [542998.010238] #PF: supervisor read access in kernel mode [542998.010878] #PF: error_code(0x0000) - not-present page [542998.011516] PGD 0 P4D 0 [542998.011929] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI [542998.012786] CPU: 3 PID: 4846 Comm: kworker/u8:1 Tainted: G B W 5.6.0-rc7-btrfs-next-58 #1 [542998.014524] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 [542998.016065] Workqueue: btrfs-scrub btrfs_work_helper [btrfs] [542998.017255] RIP: 0010:scrub_recheck_block_checksum+0xf/0x20 [btrfs] [542998.018474] Code: 4c 89 e6 ... [542998.021419] RSP: 0018:ffffa7af0375fbd8 EFLAGS: 00010202 [542998.022120] RAX: 0000000000000000 RBX: ffff9792e674d120 RCX: 0000000000000000 [542998.023178] RDX: 0000000000000001 RSI: ffff9792e674d120 RDI: ffff9792e674d120 [542998.024465] RBP: 0000000000000000 R08: 0000000000000067 R09: 0000000000000001 [542998.025462] R10: ffffa7af0375fa50 R11: 0000000000000000 R12: ffff9791f61fe800 [542998.026357] R13: ffff9792e674d120 R14: 0000000000000001 R15: ffffffffc0e3dfc0 [542998.027237] FS: 0000000000000000(0000) GS:ffff9792fb200000(0000) knlGS:0000000000000000 [542998.028327] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [542998.029261] CR2: 0000000000000028 CR3: 00000000b3b18003 CR4: 00000000003606e0 [542998.030301] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [542998.031316] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [542998.032380] Call Trace: [542998.032752] scrub_recheck_block+0x162/0x400 [btrfs] [542998.033500] ? __alloc_pages_nodemask+0x31e/0x460 [542998.034228] scrub_handle_errored_block+0x6f8/0x1920 [btrfs] [542998.035170] scrub_bio_end_io_worker+0x100/0x520 [btrfs] [542998.035991] btrfs_work_helper+0xaa/0x720 [btrfs] [542998.036735] process_one_work+0x26d/0x6a0 [542998.037275] worker_thread+0x4f/0x3e0 [542998.037740] ? process_one_work+0x6a0/0x6a0 [542998.038378] kthread+0x103/0x140 [542998.038789] ? kthread_create_worker_on_cpu+0x70/0x70 [542998.039419] ret_from_fork+0x3a/0x50 [542998.039875] Modules linked in: dm_snapshot dm_thin_pool ... [542998.047288] CR2: 0000000000000028 [542998.047724] ---[ end trace bde186e176c7f96a ]--- This issue has been around for a long time, possibly since scrub exists. The last time I ran into it was over 2 years ago. After recently fixing fstests to pass the "--full-balance" command line option to btrfs-progs when doing balance, several tests started to more heavily exercise balance with fsstress, scrub and other operations in parallel, and therefore started to hit this issue again (with btrfs/061 for example). Fix this by having scrub increment the 'trimming' counter of the block group, which pins the block group in such a way that it guarantees neither its logical address nor device extents can be reused by future block group allocations until we decrement the 'trimming' counter. Also make sure that on each iteration of scrub_stripe() we stop scrubbing the block group if it was removed already. A later patch in the series will rename the block group's 'trimming' counter and its helpers to a more generic name, since now it is not used exclusively for pinning while trimming anymore. CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-05-08 18:01:10 +08:00
spin_unlock(&cache->lock);
/*
* we need call btrfs_inc_block_group_ro() with scrubs_paused,
* to avoid deadlock caused by:
* btrfs_inc_block_group_ro()
* -> btrfs_wait_for_commit()
* -> btrfs_commit_transaction()
* -> btrfs_scrub_pause()
*/
scrub_pause_on(fs_info);
btrfs: scrub: Don't check free space before marking a block group RO [BUG] When running btrfs/072 with only one online CPU, it has a pretty high chance to fail: btrfs/072 12s ... _check_dmesg: something found in dmesg (see xfstests-dev/results//btrfs/072.dmesg) - output mismatch (see xfstests-dev/results//btrfs/072.out.bad) --- tests/btrfs/072.out 2019-10-22 15:18:14.008965340 +0800 +++ /xfstests-dev/results//btrfs/072.out.bad 2019-11-14 15:56:45.877152240 +0800 @@ -1,2 +1,3 @@ QA output created by 072 Silence is golden +Scrub find errors in "-m dup -d single" test ... And with the following call trace: BTRFS info (device dm-5): scrub: started on devid 1 ------------[ cut here ]------------ BTRFS: Transaction aborted (error -27) WARNING: CPU: 0 PID: 55087 at fs/btrfs/block-group.c:1890 btrfs_create_pending_block_groups+0x3e6/0x470 [btrfs] CPU: 0 PID: 55087 Comm: btrfs Tainted: G W O 5.4.0-rc1-custom+ #13 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:btrfs_create_pending_block_groups+0x3e6/0x470 [btrfs] Call Trace: __btrfs_end_transaction+0xdb/0x310 [btrfs] btrfs_end_transaction+0x10/0x20 [btrfs] btrfs_inc_block_group_ro+0x1c9/0x210 [btrfs] scrub_enumerate_chunks+0x264/0x940 [btrfs] btrfs_scrub_dev+0x45c/0x8f0 [btrfs] btrfs_ioctl+0x31a1/0x3fb0 [btrfs] do_vfs_ioctl+0x636/0xaa0 ksys_ioctl+0x67/0x90 __x64_sys_ioctl+0x43/0x50 do_syscall_64+0x79/0xe0 entry_SYSCALL_64_after_hwframe+0x49/0xbe ---[ end trace 166c865cec7688e7 ]--- [CAUSE] The error number -27 is -EFBIG, returned from the following call chain: btrfs_end_transaction() |- __btrfs_end_transaction() |- btrfs_create_pending_block_groups() |- btrfs_finish_chunk_alloc() |- btrfs_add_system_chunk() This happens because we have used up all space of btrfs_super_block::sys_chunk_array. The root cause is, we have the following bad loop of creating tons of system chunks: 1. The only SYSTEM chunk is being scrubbed It's very common to have only one SYSTEM chunk. 2. New SYSTEM bg will be allocated As btrfs_inc_block_group_ro() will check if we have enough space after marking current bg RO. If not, then allocate a new chunk. 3. New SYSTEM bg is still empty, will be reclaimed During the reclaim, we will mark it RO again. 4. That newly allocated empty SYSTEM bg get scrubbed We go back to step 2, as the bg is already mark RO but still not cleaned up yet. If the cleaner kthread doesn't get executed fast enough (e.g. only one CPU), then we will get more and more empty SYSTEM chunks, using up all the space of btrfs_super_block::sys_chunk_array. [FIX] Since scrub/dev-replace doesn't always need to allocate new extent, especially chunk tree extent, so we don't really need to do chunk pre-allocation. To break above spiral, here we introduce a new parameter to btrfs_inc_block_group(), @do_chunk_alloc, which indicates whether we need extra chunk pre-allocation. For relocation, we pass @do_chunk_alloc=true, while for scrub, we pass @do_chunk_alloc=false. This should keep unnecessary empty chunks from popping up for scrub. Also, since there are two parameters for btrfs_inc_block_group_ro(), add more comment for it. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-15 10:09:00 +08:00
/*
* Don't do chunk preallocation for scrub.
*
* This is especially important for SYSTEM bgs, or we can hit
* -EFBIG from btrfs_finish_chunk_alloc() like:
* 1. The only SYSTEM bg is marked RO.
* Since SYSTEM bg is small, that's pretty common.
* 2. New SYSTEM bg will be allocated
* Due to regular version will allocate new chunk.
* 3. New SYSTEM bg is empty and will get cleaned up
* Before cleanup really happens, it's marked RO again.
* 4. Empty SYSTEM bg get scrubbed
* We go back to 2.
*
* This can easily boost the amount of SYSTEM chunks if cleaner
* thread can't be triggered fast enough, and use up all space
* of btrfs_super_block::sys_chunk_array
btrfs: scrub: Require mandatory block group RO for dev-replace [BUG] For dev-replace test cases with fsstress, like btrfs/06[45] btrfs/071, looped runs can lead to random failure, where scrub finds csum error. The possibility is not high, around 1/20 to 1/100, but it's causing data corruption. The bug is observable after commit b12de52896c0 ("btrfs: scrub: Don't check free space before marking a block group RO") [CAUSE] Dev-replace has two source of writes: - Write duplication All writes to source device will also be duplicated to target device. Content: Not yet persisted data/meta - Scrub copy Dev-replace reused scrub code to iterate through existing extents, and copy the verified data to target device. Content: Previously persisted data and metadata The difference in contents makes the following race possible: Regular Writer | Dev-replace ----------------------------------------------------------------- ^ | | Preallocate one data extent | | at bytenr X, len 1M | v | ^ Commit transaction | | Now extent [X, X+1M) is in | v commit root | ================== Dev replace starts ========================= | ^ | | Scrub extent [X, X+1M) | | Read [X, X+1M) | | (The content are mostly garbage | | since it's preallocated) ^ | v | Write back happens for | | extent [X, X+512K) | | New data writes to both | | source and target dev. | v | | ^ | | Scrub writes back extent [X, X+1M) | | to target device. | | This will over write the new data in | | [X, X+512K) | v This race can only happen for nocow writes. Thus metadata and data cow writes are safe, as COW will never overwrite extents of previous transaction (in commit root). This behavior can be confirmed by disabling all fallocate related calls in fsstress (*), then all related tests can pass a 2000 run loop. *: FSSTRESS_AVOID="-f fallocate=0 -f allocsp=0 -f zero=0 -f insert=0 \ -f collapse=0 -f punch=0 -f resvsp=0" I didn't expect resvsp ioctl will fallback to fallocate in VFS... [FIX] Make dev-replace to require mandatory block group RO, and wait for current nocow writes before calling scrub_chunk(). This patch will mostly revert commit 76a8efa171bf ("btrfs: Continue replace when set_block_ro failed") for dev-replace path. The side effect is, dev-replace can be more strict on avaialble space, but definitely worth to avoid data corruption. Reported-by: Filipe Manana <fdmanana@suse.com> Fixes: 76a8efa171bf ("btrfs: Continue replace when set_block_ro failed") Fixes: b12de52896c0 ("btrfs: scrub: Don't check free space before marking a block group RO") Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-24 07:58:20 +08:00
*
* While for dev replace, we need to try our best to mark block
* group RO, to prevent race between:
* - Write duplication
* Contains latest data
* - Scrub copy
* Contains data from commit tree
*
* If target block group is not marked RO, nocow writes can
* be overwritten by scrub copy, causing data corruption.
* So for dev-replace, it's not allowed to continue if a block
* group is not RO.
btrfs: scrub: Don't check free space before marking a block group RO [BUG] When running btrfs/072 with only one online CPU, it has a pretty high chance to fail: btrfs/072 12s ... _check_dmesg: something found in dmesg (see xfstests-dev/results//btrfs/072.dmesg) - output mismatch (see xfstests-dev/results//btrfs/072.out.bad) --- tests/btrfs/072.out 2019-10-22 15:18:14.008965340 +0800 +++ /xfstests-dev/results//btrfs/072.out.bad 2019-11-14 15:56:45.877152240 +0800 @@ -1,2 +1,3 @@ QA output created by 072 Silence is golden +Scrub find errors in "-m dup -d single" test ... And with the following call trace: BTRFS info (device dm-5): scrub: started on devid 1 ------------[ cut here ]------------ BTRFS: Transaction aborted (error -27) WARNING: CPU: 0 PID: 55087 at fs/btrfs/block-group.c:1890 btrfs_create_pending_block_groups+0x3e6/0x470 [btrfs] CPU: 0 PID: 55087 Comm: btrfs Tainted: G W O 5.4.0-rc1-custom+ #13 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:btrfs_create_pending_block_groups+0x3e6/0x470 [btrfs] Call Trace: __btrfs_end_transaction+0xdb/0x310 [btrfs] btrfs_end_transaction+0x10/0x20 [btrfs] btrfs_inc_block_group_ro+0x1c9/0x210 [btrfs] scrub_enumerate_chunks+0x264/0x940 [btrfs] btrfs_scrub_dev+0x45c/0x8f0 [btrfs] btrfs_ioctl+0x31a1/0x3fb0 [btrfs] do_vfs_ioctl+0x636/0xaa0 ksys_ioctl+0x67/0x90 __x64_sys_ioctl+0x43/0x50 do_syscall_64+0x79/0xe0 entry_SYSCALL_64_after_hwframe+0x49/0xbe ---[ end trace 166c865cec7688e7 ]--- [CAUSE] The error number -27 is -EFBIG, returned from the following call chain: btrfs_end_transaction() |- __btrfs_end_transaction() |- btrfs_create_pending_block_groups() |- btrfs_finish_chunk_alloc() |- btrfs_add_system_chunk() This happens because we have used up all space of btrfs_super_block::sys_chunk_array. The root cause is, we have the following bad loop of creating tons of system chunks: 1. The only SYSTEM chunk is being scrubbed It's very common to have only one SYSTEM chunk. 2. New SYSTEM bg will be allocated As btrfs_inc_block_group_ro() will check if we have enough space after marking current bg RO. If not, then allocate a new chunk. 3. New SYSTEM bg is still empty, will be reclaimed During the reclaim, we will mark it RO again. 4. That newly allocated empty SYSTEM bg get scrubbed We go back to step 2, as the bg is already mark RO but still not cleaned up yet. If the cleaner kthread doesn't get executed fast enough (e.g. only one CPU), then we will get more and more empty SYSTEM chunks, using up all the space of btrfs_super_block::sys_chunk_array. [FIX] Since scrub/dev-replace doesn't always need to allocate new extent, especially chunk tree extent, so we don't really need to do chunk pre-allocation. To break above spiral, here we introduce a new parameter to btrfs_inc_block_group(), @do_chunk_alloc, which indicates whether we need extra chunk pre-allocation. For relocation, we pass @do_chunk_alloc=true, while for scrub, we pass @do_chunk_alloc=false. This should keep unnecessary empty chunks from popping up for scrub. Also, since there are two parameters for btrfs_inc_block_group_ro(), add more comment for it. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-15 10:09:00 +08:00
*/
btrfs: scrub: Require mandatory block group RO for dev-replace [BUG] For dev-replace test cases with fsstress, like btrfs/06[45] btrfs/071, looped runs can lead to random failure, where scrub finds csum error. The possibility is not high, around 1/20 to 1/100, but it's causing data corruption. The bug is observable after commit b12de52896c0 ("btrfs: scrub: Don't check free space before marking a block group RO") [CAUSE] Dev-replace has two source of writes: - Write duplication All writes to source device will also be duplicated to target device. Content: Not yet persisted data/meta - Scrub copy Dev-replace reused scrub code to iterate through existing extents, and copy the verified data to target device. Content: Previously persisted data and metadata The difference in contents makes the following race possible: Regular Writer | Dev-replace ----------------------------------------------------------------- ^ | | Preallocate one data extent | | at bytenr X, len 1M | v | ^ Commit transaction | | Now extent [X, X+1M) is in | v commit root | ================== Dev replace starts ========================= | ^ | | Scrub extent [X, X+1M) | | Read [X, X+1M) | | (The content are mostly garbage | | since it's preallocated) ^ | v | Write back happens for | | extent [X, X+512K) | | New data writes to both | | source and target dev. | v | | ^ | | Scrub writes back extent [X, X+1M) | | to target device. | | This will over write the new data in | | [X, X+512K) | v This race can only happen for nocow writes. Thus metadata and data cow writes are safe, as COW will never overwrite extents of previous transaction (in commit root). This behavior can be confirmed by disabling all fallocate related calls in fsstress (*), then all related tests can pass a 2000 run loop. *: FSSTRESS_AVOID="-f fallocate=0 -f allocsp=0 -f zero=0 -f insert=0 \ -f collapse=0 -f punch=0 -f resvsp=0" I didn't expect resvsp ioctl will fallback to fallocate in VFS... [FIX] Make dev-replace to require mandatory block group RO, and wait for current nocow writes before calling scrub_chunk(). This patch will mostly revert commit 76a8efa171bf ("btrfs: Continue replace when set_block_ro failed") for dev-replace path. The side effect is, dev-replace can be more strict on avaialble space, but definitely worth to avoid data corruption. Reported-by: Filipe Manana <fdmanana@suse.com> Fixes: 76a8efa171bf ("btrfs: Continue replace when set_block_ro failed") Fixes: b12de52896c0 ("btrfs: scrub: Don't check free space before marking a block group RO") Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-24 07:58:20 +08:00
ret = btrfs_inc_block_group_ro(cache, sctx->is_dev_replace);
if (!ret && sctx->is_dev_replace) {
ret = finish_extent_writes_for_zoned(root, cache);
if (ret) {
btrfs_dec_block_group_ro(cache);
scrub_pause_off(fs_info);
btrfs_put_block_group(cache);
break;
}
}
btrfs: Continue replace when set_block_ro failed xfstests/011 failed in node with small_size filesystem. Can be reproduced by following script: DEV_LIST="/dev/vdd /dev/vde" DEV_REPLACE="/dev/vdf" do_test() { local mkfs_opt="$1" local size="$2" dmesg -c >/dev/null umount $SCRATCH_MNT &>/dev/null echo mkfs.btrfs -f $mkfs_opt "${DEV_LIST[*]}" mkfs.btrfs -f $mkfs_opt "${DEV_LIST[@]}" || return 1 mount "${DEV_LIST[0]}" $SCRATCH_MNT echo -n "Writing big files" dd if=/dev/urandom of=$SCRATCH_MNT/t0 bs=1M count=1 >/dev/null 2>&1 for ((i = 1; i <= size; i++)); do echo -n . /bin/cp $SCRATCH_MNT/t0 $SCRATCH_MNT/t$i || return 1 done echo echo Start replace btrfs replace start -Bf "${DEV_LIST[0]}" "$DEV_REPLACE" $SCRATCH_MNT || { dmesg return 1 } return 0 } # Set size to value near fs size # for example, 1897 can trigger this bug in 2.6G device. # ./do_test "-d raid1 -m raid1" 1897 System will report replace fail with following warning in dmesg: [ 134.710853] BTRFS: dev_replace from /dev/vdd (devid 1) to /dev/vdf started [ 135.542390] BTRFS: btrfs_scrub_dev(/dev/vdd, 1, /dev/vdf) failed -28 [ 135.543505] ------------[ cut here ]------------ [ 135.544127] WARNING: CPU: 0 PID: 4080 at fs/btrfs/dev-replace.c:428 btrfs_dev_replace_start+0x398/0x440() [ 135.545276] Modules linked in: [ 135.545681] CPU: 0 PID: 4080 Comm: btrfs Not tainted 4.3.0 #256 [ 135.546439] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.2-0-g33fbe13 by qemu-project.org 04/01/2014 [ 135.547798] ffffffff81c5bfcf ffff88003cbb3d28 ffffffff817fe7b5 0000000000000000 [ 135.548774] ffff88003cbb3d60 ffffffff810a88f1 ffff88002b030000 00000000ffffffe4 [ 135.549774] ffff88003c080000 ffff88003c082588 ffff88003c28ab60 ffff88003cbb3d70 [ 135.550758] Call Trace: [ 135.551086] [<ffffffff817fe7b5>] dump_stack+0x44/0x55 [ 135.551737] [<ffffffff810a88f1>] warn_slowpath_common+0x81/0xc0 [ 135.552487] [<ffffffff810a89e5>] warn_slowpath_null+0x15/0x20 [ 135.553211] [<ffffffff81448c88>] btrfs_dev_replace_start+0x398/0x440 [ 135.554051] [<ffffffff81412c3e>] btrfs_ioctl+0x1d2e/0x25c0 [ 135.554722] [<ffffffff8114c7ba>] ? __audit_syscall_entry+0xaa/0xf0 [ 135.555506] [<ffffffff8111ab36>] ? current_kernel_time64+0x56/0xa0 [ 135.556304] [<ffffffff81201e3d>] do_vfs_ioctl+0x30d/0x580 [ 135.557009] [<ffffffff8114c7ba>] ? __audit_syscall_entry+0xaa/0xf0 [ 135.557855] [<ffffffff810011d1>] ? do_audit_syscall_entry+0x61/0x70 [ 135.558669] [<ffffffff8120d1c1>] ? __fget_light+0x61/0x90 [ 135.559374] [<ffffffff81202124>] SyS_ioctl+0x74/0x80 [ 135.559987] [<ffffffff81809857>] entry_SYSCALL_64_fastpath+0x12/0x6f [ 135.560842] ---[ end trace 2a5c1fc3205abbdd ]--- Reason: When big data writen to fs, the whole free space will be allocated for data chunk. And operation as scrub need to set_block_ro(), and when there is only one metadata chunk in system(or other metadata chunks are all full), the function will try to allocate a new chunk, and failed because no space in device. Fix: When set_block_ro failed for metadata chunk, it is not a problem because scrub_lock paused commit_trancaction in same time, and metadata are always cowed, so the on-the-fly writepages will not write data into same place with scrub/replace. Let replace continue in this case is no problem. Tested by above script, and xfstests/011, plus 100 times xfstests/070. Changelog v1->v2: 1: Add detail comments in source and commit-message. 2: Add dmesg detail into commit-message. 3: Limit return value of -ENOSPC to be passed. All suggested by: Filipe Manana <fdmanana@gmail.com> Suggested-by: Filipe Manana <fdmanana@gmail.com> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-11-17 18:46:17 +08:00
if (ret == 0) {
ro_set = 1;
btrfs: scrub: Require mandatory block group RO for dev-replace [BUG] For dev-replace test cases with fsstress, like btrfs/06[45] btrfs/071, looped runs can lead to random failure, where scrub finds csum error. The possibility is not high, around 1/20 to 1/100, but it's causing data corruption. The bug is observable after commit b12de52896c0 ("btrfs: scrub: Don't check free space before marking a block group RO") [CAUSE] Dev-replace has two source of writes: - Write duplication All writes to source device will also be duplicated to target device. Content: Not yet persisted data/meta - Scrub copy Dev-replace reused scrub code to iterate through existing extents, and copy the verified data to target device. Content: Previously persisted data and metadata The difference in contents makes the following race possible: Regular Writer | Dev-replace ----------------------------------------------------------------- ^ | | Preallocate one data extent | | at bytenr X, len 1M | v | ^ Commit transaction | | Now extent [X, X+1M) is in | v commit root | ================== Dev replace starts ========================= | ^ | | Scrub extent [X, X+1M) | | Read [X, X+1M) | | (The content are mostly garbage | | since it's preallocated) ^ | v | Write back happens for | | extent [X, X+512K) | | New data writes to both | | source and target dev. | v | | ^ | | Scrub writes back extent [X, X+1M) | | to target device. | | This will over write the new data in | | [X, X+512K) | v This race can only happen for nocow writes. Thus metadata and data cow writes are safe, as COW will never overwrite extents of previous transaction (in commit root). This behavior can be confirmed by disabling all fallocate related calls in fsstress (*), then all related tests can pass a 2000 run loop. *: FSSTRESS_AVOID="-f fallocate=0 -f allocsp=0 -f zero=0 -f insert=0 \ -f collapse=0 -f punch=0 -f resvsp=0" I didn't expect resvsp ioctl will fallback to fallocate in VFS... [FIX] Make dev-replace to require mandatory block group RO, and wait for current nocow writes before calling scrub_chunk(). This patch will mostly revert commit 76a8efa171bf ("btrfs: Continue replace when set_block_ro failed") for dev-replace path. The side effect is, dev-replace can be more strict on avaialble space, but definitely worth to avoid data corruption. Reported-by: Filipe Manana <fdmanana@suse.com> Fixes: 76a8efa171bf ("btrfs: Continue replace when set_block_ro failed") Fixes: b12de52896c0 ("btrfs: scrub: Don't check free space before marking a block group RO") Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-24 07:58:20 +08:00
} else if (ret == -ENOSPC && !sctx->is_dev_replace) {
btrfs: Continue replace when set_block_ro failed xfstests/011 failed in node with small_size filesystem. Can be reproduced by following script: DEV_LIST="/dev/vdd /dev/vde" DEV_REPLACE="/dev/vdf" do_test() { local mkfs_opt="$1" local size="$2" dmesg -c >/dev/null umount $SCRATCH_MNT &>/dev/null echo mkfs.btrfs -f $mkfs_opt "${DEV_LIST[*]}" mkfs.btrfs -f $mkfs_opt "${DEV_LIST[@]}" || return 1 mount "${DEV_LIST[0]}" $SCRATCH_MNT echo -n "Writing big files" dd if=/dev/urandom of=$SCRATCH_MNT/t0 bs=1M count=1 >/dev/null 2>&1 for ((i = 1; i <= size; i++)); do echo -n . /bin/cp $SCRATCH_MNT/t0 $SCRATCH_MNT/t$i || return 1 done echo echo Start replace btrfs replace start -Bf "${DEV_LIST[0]}" "$DEV_REPLACE" $SCRATCH_MNT || { dmesg return 1 } return 0 } # Set size to value near fs size # for example, 1897 can trigger this bug in 2.6G device. # ./do_test "-d raid1 -m raid1" 1897 System will report replace fail with following warning in dmesg: [ 134.710853] BTRFS: dev_replace from /dev/vdd (devid 1) to /dev/vdf started [ 135.542390] BTRFS: btrfs_scrub_dev(/dev/vdd, 1, /dev/vdf) failed -28 [ 135.543505] ------------[ cut here ]------------ [ 135.544127] WARNING: CPU: 0 PID: 4080 at fs/btrfs/dev-replace.c:428 btrfs_dev_replace_start+0x398/0x440() [ 135.545276] Modules linked in: [ 135.545681] CPU: 0 PID: 4080 Comm: btrfs Not tainted 4.3.0 #256 [ 135.546439] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.2-0-g33fbe13 by qemu-project.org 04/01/2014 [ 135.547798] ffffffff81c5bfcf ffff88003cbb3d28 ffffffff817fe7b5 0000000000000000 [ 135.548774] ffff88003cbb3d60 ffffffff810a88f1 ffff88002b030000 00000000ffffffe4 [ 135.549774] ffff88003c080000 ffff88003c082588 ffff88003c28ab60 ffff88003cbb3d70 [ 135.550758] Call Trace: [ 135.551086] [<ffffffff817fe7b5>] dump_stack+0x44/0x55 [ 135.551737] [<ffffffff810a88f1>] warn_slowpath_common+0x81/0xc0 [ 135.552487] [<ffffffff810a89e5>] warn_slowpath_null+0x15/0x20 [ 135.553211] [<ffffffff81448c88>] btrfs_dev_replace_start+0x398/0x440 [ 135.554051] [<ffffffff81412c3e>] btrfs_ioctl+0x1d2e/0x25c0 [ 135.554722] [<ffffffff8114c7ba>] ? __audit_syscall_entry+0xaa/0xf0 [ 135.555506] [<ffffffff8111ab36>] ? current_kernel_time64+0x56/0xa0 [ 135.556304] [<ffffffff81201e3d>] do_vfs_ioctl+0x30d/0x580 [ 135.557009] [<ffffffff8114c7ba>] ? __audit_syscall_entry+0xaa/0xf0 [ 135.557855] [<ffffffff810011d1>] ? do_audit_syscall_entry+0x61/0x70 [ 135.558669] [<ffffffff8120d1c1>] ? __fget_light+0x61/0x90 [ 135.559374] [<ffffffff81202124>] SyS_ioctl+0x74/0x80 [ 135.559987] [<ffffffff81809857>] entry_SYSCALL_64_fastpath+0x12/0x6f [ 135.560842] ---[ end trace 2a5c1fc3205abbdd ]--- Reason: When big data writen to fs, the whole free space will be allocated for data chunk. And operation as scrub need to set_block_ro(), and when there is only one metadata chunk in system(or other metadata chunks are all full), the function will try to allocate a new chunk, and failed because no space in device. Fix: When set_block_ro failed for metadata chunk, it is not a problem because scrub_lock paused commit_trancaction in same time, and metadata are always cowed, so the on-the-fly writepages will not write data into same place with scrub/replace. Let replace continue in this case is no problem. Tested by above script, and xfstests/011, plus 100 times xfstests/070. Changelog v1->v2: 1: Add detail comments in source and commit-message. 2: Add dmesg detail into commit-message. 3: Limit return value of -ENOSPC to be passed. All suggested by: Filipe Manana <fdmanana@gmail.com> Suggested-by: Filipe Manana <fdmanana@gmail.com> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-11-17 18:46:17 +08:00
/*
* btrfs_inc_block_group_ro return -ENOSPC when it
* failed in creating new chunk for metadata.
btrfs: scrub: Require mandatory block group RO for dev-replace [BUG] For dev-replace test cases with fsstress, like btrfs/06[45] btrfs/071, looped runs can lead to random failure, where scrub finds csum error. The possibility is not high, around 1/20 to 1/100, but it's causing data corruption. The bug is observable after commit b12de52896c0 ("btrfs: scrub: Don't check free space before marking a block group RO") [CAUSE] Dev-replace has two source of writes: - Write duplication All writes to source device will also be duplicated to target device. Content: Not yet persisted data/meta - Scrub copy Dev-replace reused scrub code to iterate through existing extents, and copy the verified data to target device. Content: Previously persisted data and metadata The difference in contents makes the following race possible: Regular Writer | Dev-replace ----------------------------------------------------------------- ^ | | Preallocate one data extent | | at bytenr X, len 1M | v | ^ Commit transaction | | Now extent [X, X+1M) is in | v commit root | ================== Dev replace starts ========================= | ^ | | Scrub extent [X, X+1M) | | Read [X, X+1M) | | (The content are mostly garbage | | since it's preallocated) ^ | v | Write back happens for | | extent [X, X+512K) | | New data writes to both | | source and target dev. | v | | ^ | | Scrub writes back extent [X, X+1M) | | to target device. | | This will over write the new data in | | [X, X+512K) | v This race can only happen for nocow writes. Thus metadata and data cow writes are safe, as COW will never overwrite extents of previous transaction (in commit root). This behavior can be confirmed by disabling all fallocate related calls in fsstress (*), then all related tests can pass a 2000 run loop. *: FSSTRESS_AVOID="-f fallocate=0 -f allocsp=0 -f zero=0 -f insert=0 \ -f collapse=0 -f punch=0 -f resvsp=0" I didn't expect resvsp ioctl will fallback to fallocate in VFS... [FIX] Make dev-replace to require mandatory block group RO, and wait for current nocow writes before calling scrub_chunk(). This patch will mostly revert commit 76a8efa171bf ("btrfs: Continue replace when set_block_ro failed") for dev-replace path. The side effect is, dev-replace can be more strict on avaialble space, but definitely worth to avoid data corruption. Reported-by: Filipe Manana <fdmanana@suse.com> Fixes: 76a8efa171bf ("btrfs: Continue replace when set_block_ro failed") Fixes: b12de52896c0 ("btrfs: scrub: Don't check free space before marking a block group RO") Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-24 07:58:20 +08:00
* It is not a problem for scrub, because
btrfs: Continue replace when set_block_ro failed xfstests/011 failed in node with small_size filesystem. Can be reproduced by following script: DEV_LIST="/dev/vdd /dev/vde" DEV_REPLACE="/dev/vdf" do_test() { local mkfs_opt="$1" local size="$2" dmesg -c >/dev/null umount $SCRATCH_MNT &>/dev/null echo mkfs.btrfs -f $mkfs_opt "${DEV_LIST[*]}" mkfs.btrfs -f $mkfs_opt "${DEV_LIST[@]}" || return 1 mount "${DEV_LIST[0]}" $SCRATCH_MNT echo -n "Writing big files" dd if=/dev/urandom of=$SCRATCH_MNT/t0 bs=1M count=1 >/dev/null 2>&1 for ((i = 1; i <= size; i++)); do echo -n . /bin/cp $SCRATCH_MNT/t0 $SCRATCH_MNT/t$i || return 1 done echo echo Start replace btrfs replace start -Bf "${DEV_LIST[0]}" "$DEV_REPLACE" $SCRATCH_MNT || { dmesg return 1 } return 0 } # Set size to value near fs size # for example, 1897 can trigger this bug in 2.6G device. # ./do_test "-d raid1 -m raid1" 1897 System will report replace fail with following warning in dmesg: [ 134.710853] BTRFS: dev_replace from /dev/vdd (devid 1) to /dev/vdf started [ 135.542390] BTRFS: btrfs_scrub_dev(/dev/vdd, 1, /dev/vdf) failed -28 [ 135.543505] ------------[ cut here ]------------ [ 135.544127] WARNING: CPU: 0 PID: 4080 at fs/btrfs/dev-replace.c:428 btrfs_dev_replace_start+0x398/0x440() [ 135.545276] Modules linked in: [ 135.545681] CPU: 0 PID: 4080 Comm: btrfs Not tainted 4.3.0 #256 [ 135.546439] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.2-0-g33fbe13 by qemu-project.org 04/01/2014 [ 135.547798] ffffffff81c5bfcf ffff88003cbb3d28 ffffffff817fe7b5 0000000000000000 [ 135.548774] ffff88003cbb3d60 ffffffff810a88f1 ffff88002b030000 00000000ffffffe4 [ 135.549774] ffff88003c080000 ffff88003c082588 ffff88003c28ab60 ffff88003cbb3d70 [ 135.550758] Call Trace: [ 135.551086] [<ffffffff817fe7b5>] dump_stack+0x44/0x55 [ 135.551737] [<ffffffff810a88f1>] warn_slowpath_common+0x81/0xc0 [ 135.552487] [<ffffffff810a89e5>] warn_slowpath_null+0x15/0x20 [ 135.553211] [<ffffffff81448c88>] btrfs_dev_replace_start+0x398/0x440 [ 135.554051] [<ffffffff81412c3e>] btrfs_ioctl+0x1d2e/0x25c0 [ 135.554722] [<ffffffff8114c7ba>] ? __audit_syscall_entry+0xaa/0xf0 [ 135.555506] [<ffffffff8111ab36>] ? current_kernel_time64+0x56/0xa0 [ 135.556304] [<ffffffff81201e3d>] do_vfs_ioctl+0x30d/0x580 [ 135.557009] [<ffffffff8114c7ba>] ? __audit_syscall_entry+0xaa/0xf0 [ 135.557855] [<ffffffff810011d1>] ? do_audit_syscall_entry+0x61/0x70 [ 135.558669] [<ffffffff8120d1c1>] ? __fget_light+0x61/0x90 [ 135.559374] [<ffffffff81202124>] SyS_ioctl+0x74/0x80 [ 135.559987] [<ffffffff81809857>] entry_SYSCALL_64_fastpath+0x12/0x6f [ 135.560842] ---[ end trace 2a5c1fc3205abbdd ]--- Reason: When big data writen to fs, the whole free space will be allocated for data chunk. And operation as scrub need to set_block_ro(), and when there is only one metadata chunk in system(or other metadata chunks are all full), the function will try to allocate a new chunk, and failed because no space in device. Fix: When set_block_ro failed for metadata chunk, it is not a problem because scrub_lock paused commit_trancaction in same time, and metadata are always cowed, so the on-the-fly writepages will not write data into same place with scrub/replace. Let replace continue in this case is no problem. Tested by above script, and xfstests/011, plus 100 times xfstests/070. Changelog v1->v2: 1: Add detail comments in source and commit-message. 2: Add dmesg detail into commit-message. 3: Limit return value of -ENOSPC to be passed. All suggested by: Filipe Manana <fdmanana@gmail.com> Suggested-by: Filipe Manana <fdmanana@gmail.com> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-11-17 18:46:17 +08:00
* metadata are always cowed, and our scrub paused
* commit_transactions.
*/
ro_set = 0;
btrfs: fix race between writes to swap files and scrub When we active a swap file, at btrfs_swap_activate(), we acquire the exclusive operation lock to prevent the physical location of the swap file extents to be changed by operations such as balance and device replace/resize/remove. We also call there can_nocow_extent() which, among other things, checks if the block group of a swap file extent is currently RO, and if it is we can not use the extent, since a write into it would result in COWing the extent. However we have no protection against a scrub operation running after we activate the swap file, which can result in the swap file extents to be COWed while the scrub is running and operating on the respective block group, because scrub turns a block group into RO before it processes it and then back again to RW mode after processing it. That means an attempt to write into a swap file extent while scrub is processing the respective block group, will result in COWing the extent, changing its physical location on disk. Fix this by making sure that block groups that have extents that are used by active swap files can not be turned into RO mode, therefore making it not possible for a scrub to turn them into RO mode. When a scrub finds a block group that can not be turned to RO due to the existence of extents used by swap files, it proceeds to the next block group and logs a warning message that mentions the block group was skipped due to active swap files - this is the same approach we currently use for balance. Fixes: ed46ff3d42378 ("Btrfs: support swap files") CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-05 20:55:37 +08:00
} else if (ret == -ETXTBSY) {
btrfs_warn(fs_info,
"skipping scrub of block group %llu due to active swapfile",
cache->start);
scrub_pause_off(fs_info);
ret = 0;
goto skip_unfreeze;
btrfs: Continue replace when set_block_ro failed xfstests/011 failed in node with small_size filesystem. Can be reproduced by following script: DEV_LIST="/dev/vdd /dev/vde" DEV_REPLACE="/dev/vdf" do_test() { local mkfs_opt="$1" local size="$2" dmesg -c >/dev/null umount $SCRATCH_MNT &>/dev/null echo mkfs.btrfs -f $mkfs_opt "${DEV_LIST[*]}" mkfs.btrfs -f $mkfs_opt "${DEV_LIST[@]}" || return 1 mount "${DEV_LIST[0]}" $SCRATCH_MNT echo -n "Writing big files" dd if=/dev/urandom of=$SCRATCH_MNT/t0 bs=1M count=1 >/dev/null 2>&1 for ((i = 1; i <= size; i++)); do echo -n . /bin/cp $SCRATCH_MNT/t0 $SCRATCH_MNT/t$i || return 1 done echo echo Start replace btrfs replace start -Bf "${DEV_LIST[0]}" "$DEV_REPLACE" $SCRATCH_MNT || { dmesg return 1 } return 0 } # Set size to value near fs size # for example, 1897 can trigger this bug in 2.6G device. # ./do_test "-d raid1 -m raid1" 1897 System will report replace fail with following warning in dmesg: [ 134.710853] BTRFS: dev_replace from /dev/vdd (devid 1) to /dev/vdf started [ 135.542390] BTRFS: btrfs_scrub_dev(/dev/vdd, 1, /dev/vdf) failed -28 [ 135.543505] ------------[ cut here ]------------ [ 135.544127] WARNING: CPU: 0 PID: 4080 at fs/btrfs/dev-replace.c:428 btrfs_dev_replace_start+0x398/0x440() [ 135.545276] Modules linked in: [ 135.545681] CPU: 0 PID: 4080 Comm: btrfs Not tainted 4.3.0 #256 [ 135.546439] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.2-0-g33fbe13 by qemu-project.org 04/01/2014 [ 135.547798] ffffffff81c5bfcf ffff88003cbb3d28 ffffffff817fe7b5 0000000000000000 [ 135.548774] ffff88003cbb3d60 ffffffff810a88f1 ffff88002b030000 00000000ffffffe4 [ 135.549774] ffff88003c080000 ffff88003c082588 ffff88003c28ab60 ffff88003cbb3d70 [ 135.550758] Call Trace: [ 135.551086] [<ffffffff817fe7b5>] dump_stack+0x44/0x55 [ 135.551737] [<ffffffff810a88f1>] warn_slowpath_common+0x81/0xc0 [ 135.552487] [<ffffffff810a89e5>] warn_slowpath_null+0x15/0x20 [ 135.553211] [<ffffffff81448c88>] btrfs_dev_replace_start+0x398/0x440 [ 135.554051] [<ffffffff81412c3e>] btrfs_ioctl+0x1d2e/0x25c0 [ 135.554722] [<ffffffff8114c7ba>] ? __audit_syscall_entry+0xaa/0xf0 [ 135.555506] [<ffffffff8111ab36>] ? current_kernel_time64+0x56/0xa0 [ 135.556304] [<ffffffff81201e3d>] do_vfs_ioctl+0x30d/0x580 [ 135.557009] [<ffffffff8114c7ba>] ? __audit_syscall_entry+0xaa/0xf0 [ 135.557855] [<ffffffff810011d1>] ? do_audit_syscall_entry+0x61/0x70 [ 135.558669] [<ffffffff8120d1c1>] ? __fget_light+0x61/0x90 [ 135.559374] [<ffffffff81202124>] SyS_ioctl+0x74/0x80 [ 135.559987] [<ffffffff81809857>] entry_SYSCALL_64_fastpath+0x12/0x6f [ 135.560842] ---[ end trace 2a5c1fc3205abbdd ]--- Reason: When big data writen to fs, the whole free space will be allocated for data chunk. And operation as scrub need to set_block_ro(), and when there is only one metadata chunk in system(or other metadata chunks are all full), the function will try to allocate a new chunk, and failed because no space in device. Fix: When set_block_ro failed for metadata chunk, it is not a problem because scrub_lock paused commit_trancaction in same time, and metadata are always cowed, so the on-the-fly writepages will not write data into same place with scrub/replace. Let replace continue in this case is no problem. Tested by above script, and xfstests/011, plus 100 times xfstests/070. Changelog v1->v2: 1: Add detail comments in source and commit-message. 2: Add dmesg detail into commit-message. 3: Limit return value of -ENOSPC to be passed. All suggested by: Filipe Manana <fdmanana@gmail.com> Suggested-by: Filipe Manana <fdmanana@gmail.com> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-11-17 18:46:17 +08:00
} else {
btrfs_warn(fs_info,
"failed setting block group ro: %d", ret);
btrfs_unfreeze_block_group(cache);
btrfs_put_block_group(cache);
btrfs: scrub: Require mandatory block group RO for dev-replace [BUG] For dev-replace test cases with fsstress, like btrfs/06[45] btrfs/071, looped runs can lead to random failure, where scrub finds csum error. The possibility is not high, around 1/20 to 1/100, but it's causing data corruption. The bug is observable after commit b12de52896c0 ("btrfs: scrub: Don't check free space before marking a block group RO") [CAUSE] Dev-replace has two source of writes: - Write duplication All writes to source device will also be duplicated to target device. Content: Not yet persisted data/meta - Scrub copy Dev-replace reused scrub code to iterate through existing extents, and copy the verified data to target device. Content: Previously persisted data and metadata The difference in contents makes the following race possible: Regular Writer | Dev-replace ----------------------------------------------------------------- ^ | | Preallocate one data extent | | at bytenr X, len 1M | v | ^ Commit transaction | | Now extent [X, X+1M) is in | v commit root | ================== Dev replace starts ========================= | ^ | | Scrub extent [X, X+1M) | | Read [X, X+1M) | | (The content are mostly garbage | | since it's preallocated) ^ | v | Write back happens for | | extent [X, X+512K) | | New data writes to both | | source and target dev. | v | | ^ | | Scrub writes back extent [X, X+1M) | | to target device. | | This will over write the new data in | | [X, X+512K) | v This race can only happen for nocow writes. Thus metadata and data cow writes are safe, as COW will never overwrite extents of previous transaction (in commit root). This behavior can be confirmed by disabling all fallocate related calls in fsstress (*), then all related tests can pass a 2000 run loop. *: FSSTRESS_AVOID="-f fallocate=0 -f allocsp=0 -f zero=0 -f insert=0 \ -f collapse=0 -f punch=0 -f resvsp=0" I didn't expect resvsp ioctl will fallback to fallocate in VFS... [FIX] Make dev-replace to require mandatory block group RO, and wait for current nocow writes before calling scrub_chunk(). This patch will mostly revert commit 76a8efa171bf ("btrfs: Continue replace when set_block_ro failed") for dev-replace path. The side effect is, dev-replace can be more strict on avaialble space, but definitely worth to avoid data corruption. Reported-by: Filipe Manana <fdmanana@suse.com> Fixes: 76a8efa171bf ("btrfs: Continue replace when set_block_ro failed") Fixes: b12de52896c0 ("btrfs: scrub: Don't check free space before marking a block group RO") Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-24 07:58:20 +08:00
scrub_pause_off(fs_info);
break;
}
btrfs: scrub: Require mandatory block group RO for dev-replace [BUG] For dev-replace test cases with fsstress, like btrfs/06[45] btrfs/071, looped runs can lead to random failure, where scrub finds csum error. The possibility is not high, around 1/20 to 1/100, but it's causing data corruption. The bug is observable after commit b12de52896c0 ("btrfs: scrub: Don't check free space before marking a block group RO") [CAUSE] Dev-replace has two source of writes: - Write duplication All writes to source device will also be duplicated to target device. Content: Not yet persisted data/meta - Scrub copy Dev-replace reused scrub code to iterate through existing extents, and copy the verified data to target device. Content: Previously persisted data and metadata The difference in contents makes the following race possible: Regular Writer | Dev-replace ----------------------------------------------------------------- ^ | | Preallocate one data extent | | at bytenr X, len 1M | v | ^ Commit transaction | | Now extent [X, X+1M) is in | v commit root | ================== Dev replace starts ========================= | ^ | | Scrub extent [X, X+1M) | | Read [X, X+1M) | | (The content are mostly garbage | | since it's preallocated) ^ | v | Write back happens for | | extent [X, X+512K) | | New data writes to both | | source and target dev. | v | | ^ | | Scrub writes back extent [X, X+1M) | | to target device. | | This will over write the new data in | | [X, X+512K) | v This race can only happen for nocow writes. Thus metadata and data cow writes are safe, as COW will never overwrite extents of previous transaction (in commit root). This behavior can be confirmed by disabling all fallocate related calls in fsstress (*), then all related tests can pass a 2000 run loop. *: FSSTRESS_AVOID="-f fallocate=0 -f allocsp=0 -f zero=0 -f insert=0 \ -f collapse=0 -f punch=0 -f resvsp=0" I didn't expect resvsp ioctl will fallback to fallocate in VFS... [FIX] Make dev-replace to require mandatory block group RO, and wait for current nocow writes before calling scrub_chunk(). This patch will mostly revert commit 76a8efa171bf ("btrfs: Continue replace when set_block_ro failed") for dev-replace path. The side effect is, dev-replace can be more strict on avaialble space, but definitely worth to avoid data corruption. Reported-by: Filipe Manana <fdmanana@suse.com> Fixes: 76a8efa171bf ("btrfs: Continue replace when set_block_ro failed") Fixes: b12de52896c0 ("btrfs: scrub: Don't check free space before marking a block group RO") Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-24 07:58:20 +08:00
/*
* Now the target block is marked RO, wait for nocow writes to
* finish before dev-replace.
* COW is fine, as COW never overwrites extents in commit tree.
*/
if (sctx->is_dev_replace) {
btrfs_wait_nocow_writers(cache);
btrfs_wait_ordered_roots(fs_info, U64_MAX, cache->start,
cache->length);
}
scrub_pause_off(fs_info);
down_write(&dev_replace->rwsem);
dev_replace->cursor_right = found_key.offset + length;
dev_replace->cursor_left = found_key.offset;
dev_replace->item_needs_writeback = 1;
up_write(&dev_replace->rwsem);
ret = scrub_chunk(sctx, scrub_dev, chunk_offset, length,
found_key.offset, cache);
/*
* flush, submit all pending read and write bios, afterwards
* wait for them.
* Note that in the dev replace case, a read request causes
* write requests that are submitted in the read completion
* worker. Therefore in the current situation, it is required
* that all write requests are flushed, so that all read and
* write requests are really completed when bios_in_flight
* changes to 0.
*/
sctx->flush_all_writes = true;
scrub_submit(sctx);
mutex_lock(&sctx->wr_lock);
scrub_wr_submit(sctx);
mutex_unlock(&sctx->wr_lock);
wait_event(sctx->list_wait,
atomic_read(&sctx->bios_in_flight) == 0);
scrub_pause_on(fs_info);
/*
* must be called before we decrease @scrub_paused.
* make sure we don't block transaction commit while
* we are waiting pending workers finished.
*/
wait_event(sctx->list_wait,
atomic_read(&sctx->workers_pending) == 0);
sctx->flush_all_writes = false;
scrub_pause_off(fs_info);
btrfs: zoned: mark block groups to copy for device-replace This is the 1/4 patch to support device-replace on zoned filesystems. We have two types of IOs during the device replace process. One is an IO to "copy" (by the scrub functions) all the device extents from the source device to the destination device. The other one is an IO to "clone" (by handle_ops_on_dev_replace()) new incoming write IOs from users to the source device into the target device. Cloning incoming IOs can break the sequential write rule in on target device. When a write is mapped in the middle of a block group, the IO is directed to the middle of a target device zone, which breaks the sequential write requirement. However, the cloning function cannot be disabled since incoming IOs targeting already copied device extents must be cloned so that the IO is executed on the target device. We cannot use dev_replace->cursor_{left,right} to determine whether a bio is going to a not yet copied region. Since we have a time gap between finishing btrfs_scrub_dev() and rewriting the mapping tree in btrfs_dev_replace_finishing(), we can have a newly allocated device extent which is never cloned nor copied. So the point is to copy only already existing device extents. This patch introduces mark_block_group_to_copy() to mark existing block groups as a target of copying. Then, handle_ops_on_dev_replace() and dev-replace can check the flag to do their job. Also, btrfs_finish_block_group_to_copy() will check if the copied stripe is the last stripe in the block group. With the last stripe copied, the to_copy flag is finally disabled. Afterwards we can safely clone incoming IOs on this block group. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-04 18:22:11 +08:00
if (sctx->is_dev_replace &&
!btrfs_finish_block_group_to_copy(dev_replace->srcdev,
cache, found_key.offset))
ro_set = 0;
down_write(&dev_replace->rwsem);
dev_replace->cursor_left = dev_replace->cursor_right;
dev_replace->item_needs_writeback = 1;
up_write(&dev_replace->rwsem);
btrfs: Continue replace when set_block_ro failed xfstests/011 failed in node with small_size filesystem. Can be reproduced by following script: DEV_LIST="/dev/vdd /dev/vde" DEV_REPLACE="/dev/vdf" do_test() { local mkfs_opt="$1" local size="$2" dmesg -c >/dev/null umount $SCRATCH_MNT &>/dev/null echo mkfs.btrfs -f $mkfs_opt "${DEV_LIST[*]}" mkfs.btrfs -f $mkfs_opt "${DEV_LIST[@]}" || return 1 mount "${DEV_LIST[0]}" $SCRATCH_MNT echo -n "Writing big files" dd if=/dev/urandom of=$SCRATCH_MNT/t0 bs=1M count=1 >/dev/null 2>&1 for ((i = 1; i <= size; i++)); do echo -n . /bin/cp $SCRATCH_MNT/t0 $SCRATCH_MNT/t$i || return 1 done echo echo Start replace btrfs replace start -Bf "${DEV_LIST[0]}" "$DEV_REPLACE" $SCRATCH_MNT || { dmesg return 1 } return 0 } # Set size to value near fs size # for example, 1897 can trigger this bug in 2.6G device. # ./do_test "-d raid1 -m raid1" 1897 System will report replace fail with following warning in dmesg: [ 134.710853] BTRFS: dev_replace from /dev/vdd (devid 1) to /dev/vdf started [ 135.542390] BTRFS: btrfs_scrub_dev(/dev/vdd, 1, /dev/vdf) failed -28 [ 135.543505] ------------[ cut here ]------------ [ 135.544127] WARNING: CPU: 0 PID: 4080 at fs/btrfs/dev-replace.c:428 btrfs_dev_replace_start+0x398/0x440() [ 135.545276] Modules linked in: [ 135.545681] CPU: 0 PID: 4080 Comm: btrfs Not tainted 4.3.0 #256 [ 135.546439] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.2-0-g33fbe13 by qemu-project.org 04/01/2014 [ 135.547798] ffffffff81c5bfcf ffff88003cbb3d28 ffffffff817fe7b5 0000000000000000 [ 135.548774] ffff88003cbb3d60 ffffffff810a88f1 ffff88002b030000 00000000ffffffe4 [ 135.549774] ffff88003c080000 ffff88003c082588 ffff88003c28ab60 ffff88003cbb3d70 [ 135.550758] Call Trace: [ 135.551086] [<ffffffff817fe7b5>] dump_stack+0x44/0x55 [ 135.551737] [<ffffffff810a88f1>] warn_slowpath_common+0x81/0xc0 [ 135.552487] [<ffffffff810a89e5>] warn_slowpath_null+0x15/0x20 [ 135.553211] [<ffffffff81448c88>] btrfs_dev_replace_start+0x398/0x440 [ 135.554051] [<ffffffff81412c3e>] btrfs_ioctl+0x1d2e/0x25c0 [ 135.554722] [<ffffffff8114c7ba>] ? __audit_syscall_entry+0xaa/0xf0 [ 135.555506] [<ffffffff8111ab36>] ? current_kernel_time64+0x56/0xa0 [ 135.556304] [<ffffffff81201e3d>] do_vfs_ioctl+0x30d/0x580 [ 135.557009] [<ffffffff8114c7ba>] ? __audit_syscall_entry+0xaa/0xf0 [ 135.557855] [<ffffffff810011d1>] ? do_audit_syscall_entry+0x61/0x70 [ 135.558669] [<ffffffff8120d1c1>] ? __fget_light+0x61/0x90 [ 135.559374] [<ffffffff81202124>] SyS_ioctl+0x74/0x80 [ 135.559987] [<ffffffff81809857>] entry_SYSCALL_64_fastpath+0x12/0x6f [ 135.560842] ---[ end trace 2a5c1fc3205abbdd ]--- Reason: When big data writen to fs, the whole free space will be allocated for data chunk. And operation as scrub need to set_block_ro(), and when there is only one metadata chunk in system(or other metadata chunks are all full), the function will try to allocate a new chunk, and failed because no space in device. Fix: When set_block_ro failed for metadata chunk, it is not a problem because scrub_lock paused commit_trancaction in same time, and metadata are always cowed, so the on-the-fly writepages will not write data into same place with scrub/replace. Let replace continue in this case is no problem. Tested by above script, and xfstests/011, plus 100 times xfstests/070. Changelog v1->v2: 1: Add detail comments in source and commit-message. 2: Add dmesg detail into commit-message. 3: Limit return value of -ENOSPC to be passed. All suggested by: Filipe Manana <fdmanana@gmail.com> Suggested-by: Filipe Manana <fdmanana@gmail.com> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-11-17 18:46:17 +08:00
if (ro_set)
btrfs_dec_block_group_ro(cache);
/*
* We might have prevented the cleaner kthread from deleting
* this block group if it was already unused because we raced
* and set it to RO mode first. So add it back to the unused
* list, otherwise it might not ever be deleted unless a manual
* balance is triggered or it becomes used and unused again.
*/
spin_lock(&cache->lock);
if (!cache->removed && !cache->ro && cache->reserved == 0 &&
cache->used == 0) {
spin_unlock(&cache->lock);
btrfs: handle empty block_group removal for async discard block_group removal is a little tricky. It can race with the extent allocator, the cleaner thread, and balancing. The current path is for a block_group to be added to the unused_bgs list. Then, when the cleaner thread comes around, it starts a transaction and then proceeds with removing the block_group. Extents that are pinned are subsequently removed from the pinned trees and then eventually a discard is issued for the entire block_group. Async discard introduces another player into the game, the discard workqueue. While it has none of the racing issues, the new problem is ensuring we don't leave free space untrimmed prior to forgetting the block_group. This is handled by placing fully free block_groups on a separate discard queue. This is necessary to maintain discarding order as in the future we will slowly trim even fully free block_groups. The ordering helps us make progress on the same block_group rather than say the last fully freed block_group or needing to search through the fully freed block groups at the beginning of a list and insert after. The new order of events is a fully freed block group gets placed on the unused discard queue first. Once it's processed, it will be placed on the unusued_bgs list and then the original sequence of events will happen, just without the final whole block_group discard. The mount flags can change when processing unused_bgs, so when flipping from DISCARD to DISCARD_ASYNC, the unused_bgs must be punted to the discard_list to be trimmed. If we flip off DISCARD_ASYNC, we punt free block groups on the discard_list to the unused_bg queue which will do the final discard for us. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Dennis Zhou <dennis@kernel.org> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-12-14 08:22:15 +08:00
if (btrfs_test_opt(fs_info, DISCARD_ASYNC))
btrfs_discard_queue_work(&fs_info->discard_ctl,
cache);
else
btrfs_mark_bg_unused(cache);
} else {
spin_unlock(&cache->lock);
}
btrfs: fix race between writes to swap files and scrub When we active a swap file, at btrfs_swap_activate(), we acquire the exclusive operation lock to prevent the physical location of the swap file extents to be changed by operations such as balance and device replace/resize/remove. We also call there can_nocow_extent() which, among other things, checks if the block group of a swap file extent is currently RO, and if it is we can not use the extent, since a write into it would result in COWing the extent. However we have no protection against a scrub operation running after we activate the swap file, which can result in the swap file extents to be COWed while the scrub is running and operating on the respective block group, because scrub turns a block group into RO before it processes it and then back again to RW mode after processing it. That means an attempt to write into a swap file extent while scrub is processing the respective block group, will result in COWing the extent, changing its physical location on disk. Fix this by making sure that block groups that have extents that are used by active swap files can not be turned into RO mode, therefore making it not possible for a scrub to turn them into RO mode. When a scrub finds a block group that can not be turned to RO due to the existence of extents used by swap files, it proceeds to the next block group and logs a warning message that mentions the block group was skipped due to active swap files - this is the same approach we currently use for balance. Fixes: ed46ff3d42378 ("Btrfs: support swap files") CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-05 20:55:37 +08:00
skip_unfreeze:
btrfs_unfreeze_block_group(cache);
btrfs_put_block_group(cache);
if (ret)
break;
if (sctx->is_dev_replace &&
atomic64_read(&dev_replace->num_write_errors) > 0) {
ret = -EIO;
break;
}
if (sctx->stat.malloc_errors > 0) {
ret = -ENOMEM;
break;
}
skip:
key.offset = found_key.offset + length;
btrfs_release_path(path);
}
btrfs_free_path(path);
return ret;
}
static noinline_for_stack int scrub_supers(struct scrub_ctx *sctx,
struct btrfs_device *scrub_dev)
{
int i;
u64 bytenr;
u64 gen;
int ret;
struct btrfs_fs_info *fs_info = sctx->fs_info;
if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
btrfs: return EROFS for BTRFS_FS_STATE_ERROR cases Eric reported seeing this message while running generic/475 BTRFS: error (device dm-3) in btrfs_sync_log:3084: errno=-117 Filesystem corrupted Full stack trace: BTRFS: error (device dm-0) in btrfs_commit_transaction:2323: errno=-5 IO failure (Error while writing out transaction) BTRFS info (device dm-0): forced readonly BTRFS warning (device dm-0): Skipping commit of aborted transaction. ------------[ cut here ]------------ BTRFS: error (device dm-0) in cleanup_transaction:1894: errno=-5 IO failure BTRFS: Transaction aborted (error -117) BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c6480 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c6488 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c6490 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c6498 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c64a0 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c64a8 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c64b0 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c64b8 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c64c0 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3572 rw 0,0 sector 0x1b85e8 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3572 rw 0,0 sector 0x1b85f0 len 4096 err no 10 WARNING: CPU: 3 PID: 23985 at fs/btrfs/tree-log.c:3084 btrfs_sync_log+0xbc8/0xd60 [btrfs] BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d4288 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d4290 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d4298 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42a0 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42a8 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42b0 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42b8 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42c0 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42c8 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42d0 len 4096 err no 10 CPU: 3 PID: 23985 Comm: fsstress Tainted: G W L 5.8.0-rc4-default+ #1181 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba527-rebuilt.opensuse.org 04/01/2014 RIP: 0010:btrfs_sync_log+0xbc8/0xd60 [btrfs] RSP: 0018:ffff909a44d17bd0 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000001 RDX: ffff8f3be41cb940 RSI: ffffffffb0108d2b RDI: ffffffffb0108ff7 RBP: ffff909a44d17e70 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000037988 R12: ffff8f3bd20e4000 R13: ffff8f3bd20e4428 R14: 00000000ffffff8b R15: ffff909a44d17c70 FS: 00007f6a6ed3fb80(0000) GS:ffff8f3c3dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6a6ed3e000 CR3: 00000000525c0003 CR4: 0000000000160ee0 Call Trace: ? finish_wait+0x90/0x90 ? __mutex_unlock_slowpath+0x45/0x2a0 ? lock_acquire+0xa3/0x440 ? lockref_put_or_lock+0x9/0x30 ? dput+0x20/0x4a0 ? dput+0x20/0x4a0 ? do_raw_spin_unlock+0x4b/0xc0 ? _raw_spin_unlock+0x1f/0x30 btrfs_sync_file+0x335/0x490 [btrfs] do_fsync+0x38/0x70 __x64_sys_fsync+0x10/0x20 do_syscall_64+0x50/0xe0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f6a6ef1b6e3 Code: Bad RIP value. RSP: 002b:00007ffd01e20038 EFLAGS: 00000246 ORIG_RAX: 000000000000004a RAX: ffffffffffffffda RBX: 000000000007a120 RCX: 00007f6a6ef1b6e3 RDX: 00007ffd01e1ffa0 RSI: 00007ffd01e1ffa0 RDI: 0000000000000003 RBP: 0000000000000003 R08: 0000000000000001 R09: 00007ffd01e2004c R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000009f R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 irq event stamp: 0 hardirqs last enabled at (0): [<0000000000000000>] 0x0 hardirqs last disabled at (0): [<ffffffffb007fe0b>] copy_process+0x67b/0x1b00 softirqs last enabled at (0): [<ffffffffb007fe0b>] copy_process+0x67b/0x1b00 softirqs last disabled at (0): [<0000000000000000>] 0x0 ---[ end trace af146e0e38433456 ]--- BTRFS: error (device dm-0) in btrfs_sync_log:3084: errno=-117 Filesystem corrupted This ret came from btrfs_write_marked_extents(). If we get an aborted transaction via EIO before, we'll see it in btree_write_cache_pages() and return EUCLEAN, which gets printed as "Filesystem corrupted". Except we shouldn't be returning EUCLEAN here, we need to be returning EROFS because EUCLEAN is reserved for actual corruption, not IO errors. We are inconsistent about our handling of BTRFS_FS_STATE_ERROR elsewhere, but we want to use EROFS for this particular case. The original transaction abort has the real error code for why we ended up with an aborted transaction, all subsequent actions just need to return EROFS because they may not have a trans handle and have no idea about the original cause of the abort. After patch "btrfs: don't WARN if we abort a transaction with EROFS" the stacktrace will not be dumped either. Reported-by: Eric Sandeen <esandeen@redhat.com> CC: stable@vger.kernel.org # 5.4+ Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ add full test stacktrace ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-21 22:38:37 +08:00
return -EROFS;
/* Seed devices of a new filesystem has their own generation. */
if (scrub_dev->fs_devices != fs_info->fs_devices)
gen = scrub_dev->generation;
else
gen = fs_info->last_trans_committed;
for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
bytenr = btrfs_sb_offset(i);
if (bytenr + BTRFS_SUPER_INFO_SIZE >
scrub_dev->commit_total_bytes)
break;
btrfs: implement log-structured superblock for ZONED mode Superblock (and its copies) is the only data structure in btrfs which has a fixed location on a device. Since we cannot overwrite in a sequential write required zone, we cannot place superblock in the zone. One easy solution is limiting superblock and copies to be placed only in conventional zones. However, this method has two downsides: one is reduced number of superblock copies. The location of the second copy of superblock is 256GB, which is in a sequential write required zone on typical devices in the market today. So, the number of superblock and copies is limited to be two. Second downside is that we cannot support devices which have no conventional zones at all. To solve these two problems, we employ superblock log writing. It uses two adjacent zones as a circular buffer to write updated superblocks. Once the first zone is filled up, start writing into the second one. Then, when both zones are filled up and before starting to write to the first zone again, it reset the first zone. We can determine the position of the latest superblock by reading write pointer information from a device. One corner case is when both zones are full. For this situation, we read out the last superblock of each zone, and compare them to determine which zone is older. The following zones are reserved as the circular buffer on ZONED btrfs. - The primary superblock: zones 0 and 1 - The first copy: zones 16 and 17 - The second copy: zones 1024 or zone at 256GB which is minimum, and next to it If these reserved zones are conventional, superblock is written fixed at the start of the zone without logging. Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-10 19:26:14 +08:00
if (!btrfs_check_super_location(scrub_dev, bytenr))
continue;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
ret = scrub_pages(sctx, bytenr, BTRFS_SUPER_INFO_SIZE, bytenr,
scrub_dev, BTRFS_EXTENT_FLAG_SUPER, gen, i,
NULL, bytenr);
if (ret)
return ret;
}
wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
return 0;
}
btrfs: allocate scrub workqueues outside of locks I got the following lockdep splat while testing: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00172-g021118712e59 #932 Not tainted ------------------------------------------------------ btrfs/229626 is trying to acquire lock: ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450 but task is already holding lock: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_scrub_dev+0x11c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #1 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 cpus_read_lock+0x39/0xb0 alloc_workqueue+0x378/0x450 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->scrub_lock); lock(&fs_devs->device_list_mutex); lock(&fs_info->scrub_lock); lock(cpu_hotplug_lock); *** DEADLOCK *** 2 locks held by btrfs/229626: #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630 #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 stack backtrace: CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? alloc_workqueue+0x378/0x450 cpus_read_lock+0x39/0xb0 ? alloc_workqueue+0x378/0x450 alloc_workqueue+0x378/0x450 ? rcu_read_lock_sched_held+0x52/0x80 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 ? start_transaction+0xd1/0x5d0 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ? do_sigaction+0x102/0x250 ? lockdep_hardirqs_on_prepare+0xca/0x160 ? _raw_spin_unlock_irq+0x24/0x30 ? trace_hardirqs_on+0x1c/0xe0 ? _raw_spin_unlock_irq+0x24/0x30 ? do_sigaction+0x102/0x250 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens because we're allocating the scrub workqueues under the scrub and device list mutex, which brings in a whole host of other dependencies. Because the work queue allocation is done with GFP_KERNEL, it can trigger reclaim, which can lead to a transaction commit, which in turns needs the device_list_mutex, it can lead to a deadlock. A different problem for which this fix is a solution. Fix this by moving the actual allocation outside of the scrub lock, and then only take the lock once we're ready to actually assign them to the fs_info. We'll now have to cleanup the workqueues in a few more places, so I've added a helper to do the refcount dance to safely free the workqueues. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 23:42:29 +08:00
static void scrub_workers_put(struct btrfs_fs_info *fs_info)
{
if (refcount_dec_and_mutex_lock(&fs_info->scrub_workers_refcnt,
&fs_info->scrub_lock)) {
struct btrfs_workqueue *scrub_workers = NULL;
struct btrfs_workqueue *scrub_wr_comp = NULL;
struct btrfs_workqueue *scrub_parity = NULL;
scrub_workers = fs_info->scrub_workers;
scrub_wr_comp = fs_info->scrub_wr_completion_workers;
scrub_parity = fs_info->scrub_parity_workers;
fs_info->scrub_workers = NULL;
fs_info->scrub_wr_completion_workers = NULL;
fs_info->scrub_parity_workers = NULL;
mutex_unlock(&fs_info->scrub_lock);
btrfs_destroy_workqueue(scrub_workers);
btrfs_destroy_workqueue(scrub_wr_comp);
btrfs_destroy_workqueue(scrub_parity);
}
}
/*
* get a reference count on fs_info->scrub_workers. start worker if necessary
*/
static noinline_for_stack int scrub_workers_get(struct btrfs_fs_info *fs_info,
int is_dev_replace)
{
btrfs: allocate scrub workqueues outside of locks I got the following lockdep splat while testing: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00172-g021118712e59 #932 Not tainted ------------------------------------------------------ btrfs/229626 is trying to acquire lock: ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450 but task is already holding lock: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_scrub_dev+0x11c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #1 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 cpus_read_lock+0x39/0xb0 alloc_workqueue+0x378/0x450 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->scrub_lock); lock(&fs_devs->device_list_mutex); lock(&fs_info->scrub_lock); lock(cpu_hotplug_lock); *** DEADLOCK *** 2 locks held by btrfs/229626: #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630 #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 stack backtrace: CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? alloc_workqueue+0x378/0x450 cpus_read_lock+0x39/0xb0 ? alloc_workqueue+0x378/0x450 alloc_workqueue+0x378/0x450 ? rcu_read_lock_sched_held+0x52/0x80 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 ? start_transaction+0xd1/0x5d0 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ? do_sigaction+0x102/0x250 ? lockdep_hardirqs_on_prepare+0xca/0x160 ? _raw_spin_unlock_irq+0x24/0x30 ? trace_hardirqs_on+0x1c/0xe0 ? _raw_spin_unlock_irq+0x24/0x30 ? do_sigaction+0x102/0x250 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens because we're allocating the scrub workqueues under the scrub and device list mutex, which brings in a whole host of other dependencies. Because the work queue allocation is done with GFP_KERNEL, it can trigger reclaim, which can lead to a transaction commit, which in turns needs the device_list_mutex, it can lead to a deadlock. A different problem for which this fix is a solution. Fix this by moving the actual allocation outside of the scrub lock, and then only take the lock once we're ready to actually assign them to the fs_info. We'll now have to cleanup the workqueues in a few more places, so I've added a helper to do the refcount dance to safely free the workqueues. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 23:42:29 +08:00
struct btrfs_workqueue *scrub_workers = NULL;
struct btrfs_workqueue *scrub_wr_comp = NULL;
struct btrfs_workqueue *scrub_parity = NULL;
unsigned int flags = WQ_FREEZABLE | WQ_UNBOUND;
int max_active = fs_info->thread_pool_size;
btrfs: allocate scrub workqueues outside of locks I got the following lockdep splat while testing: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00172-g021118712e59 #932 Not tainted ------------------------------------------------------ btrfs/229626 is trying to acquire lock: ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450 but task is already holding lock: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_scrub_dev+0x11c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #1 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 cpus_read_lock+0x39/0xb0 alloc_workqueue+0x378/0x450 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->scrub_lock); lock(&fs_devs->device_list_mutex); lock(&fs_info->scrub_lock); lock(cpu_hotplug_lock); *** DEADLOCK *** 2 locks held by btrfs/229626: #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630 #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 stack backtrace: CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? alloc_workqueue+0x378/0x450 cpus_read_lock+0x39/0xb0 ? alloc_workqueue+0x378/0x450 alloc_workqueue+0x378/0x450 ? rcu_read_lock_sched_held+0x52/0x80 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 ? start_transaction+0xd1/0x5d0 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ? do_sigaction+0x102/0x250 ? lockdep_hardirqs_on_prepare+0xca/0x160 ? _raw_spin_unlock_irq+0x24/0x30 ? trace_hardirqs_on+0x1c/0xe0 ? _raw_spin_unlock_irq+0x24/0x30 ? do_sigaction+0x102/0x250 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens because we're allocating the scrub workqueues under the scrub and device list mutex, which brings in a whole host of other dependencies. Because the work queue allocation is done with GFP_KERNEL, it can trigger reclaim, which can lead to a transaction commit, which in turns needs the device_list_mutex, it can lead to a deadlock. A different problem for which this fix is a solution. Fix this by moving the actual allocation outside of the scrub lock, and then only take the lock once we're ready to actually assign them to the fs_info. We'll now have to cleanup the workqueues in a few more places, so I've added a helper to do the refcount dance to safely free the workqueues. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 23:42:29 +08:00
int ret = -ENOMEM;
btrfs: allocate scrub workqueues outside of locks I got the following lockdep splat while testing: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00172-g021118712e59 #932 Not tainted ------------------------------------------------------ btrfs/229626 is trying to acquire lock: ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450 but task is already holding lock: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_scrub_dev+0x11c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #1 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 cpus_read_lock+0x39/0xb0 alloc_workqueue+0x378/0x450 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->scrub_lock); lock(&fs_devs->device_list_mutex); lock(&fs_info->scrub_lock); lock(cpu_hotplug_lock); *** DEADLOCK *** 2 locks held by btrfs/229626: #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630 #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 stack backtrace: CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? alloc_workqueue+0x378/0x450 cpus_read_lock+0x39/0xb0 ? alloc_workqueue+0x378/0x450 alloc_workqueue+0x378/0x450 ? rcu_read_lock_sched_held+0x52/0x80 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 ? start_transaction+0xd1/0x5d0 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ? do_sigaction+0x102/0x250 ? lockdep_hardirqs_on_prepare+0xca/0x160 ? _raw_spin_unlock_irq+0x24/0x30 ? trace_hardirqs_on+0x1c/0xe0 ? _raw_spin_unlock_irq+0x24/0x30 ? do_sigaction+0x102/0x250 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens because we're allocating the scrub workqueues under the scrub and device list mutex, which brings in a whole host of other dependencies. Because the work queue allocation is done with GFP_KERNEL, it can trigger reclaim, which can lead to a transaction commit, which in turns needs the device_list_mutex, it can lead to a deadlock. A different problem for which this fix is a solution. Fix this by moving the actual allocation outside of the scrub lock, and then only take the lock once we're ready to actually assign them to the fs_info. We'll now have to cleanup the workqueues in a few more places, so I've added a helper to do the refcount dance to safely free the workqueues. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 23:42:29 +08:00
if (refcount_inc_not_zero(&fs_info->scrub_workers_refcnt))
return 0;
btrfs: allocate scrub workqueues outside of locks I got the following lockdep splat while testing: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00172-g021118712e59 #932 Not tainted ------------------------------------------------------ btrfs/229626 is trying to acquire lock: ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450 but task is already holding lock: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_scrub_dev+0x11c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #1 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 cpus_read_lock+0x39/0xb0 alloc_workqueue+0x378/0x450 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->scrub_lock); lock(&fs_devs->device_list_mutex); lock(&fs_info->scrub_lock); lock(cpu_hotplug_lock); *** DEADLOCK *** 2 locks held by btrfs/229626: #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630 #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 stack backtrace: CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? alloc_workqueue+0x378/0x450 cpus_read_lock+0x39/0xb0 ? alloc_workqueue+0x378/0x450 alloc_workqueue+0x378/0x450 ? rcu_read_lock_sched_held+0x52/0x80 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 ? start_transaction+0xd1/0x5d0 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ? do_sigaction+0x102/0x250 ? lockdep_hardirqs_on_prepare+0xca/0x160 ? _raw_spin_unlock_irq+0x24/0x30 ? trace_hardirqs_on+0x1c/0xe0 ? _raw_spin_unlock_irq+0x24/0x30 ? do_sigaction+0x102/0x250 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens because we're allocating the scrub workqueues under the scrub and device list mutex, which brings in a whole host of other dependencies. Because the work queue allocation is done with GFP_KERNEL, it can trigger reclaim, which can lead to a transaction commit, which in turns needs the device_list_mutex, it can lead to a deadlock. A different problem for which this fix is a solution. Fix this by moving the actual allocation outside of the scrub lock, and then only take the lock once we're ready to actually assign them to the fs_info. We'll now have to cleanup the workqueues in a few more places, so I've added a helper to do the refcount dance to safely free the workqueues. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 23:42:29 +08:00
scrub_workers = btrfs_alloc_workqueue(fs_info, "scrub", flags,
is_dev_replace ? 1 : max_active, 4);
if (!scrub_workers)
goto fail_scrub_workers;
btrfs: allocate scrub workqueues outside of locks I got the following lockdep splat while testing: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00172-g021118712e59 #932 Not tainted ------------------------------------------------------ btrfs/229626 is trying to acquire lock: ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450 but task is already holding lock: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_scrub_dev+0x11c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #1 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 cpus_read_lock+0x39/0xb0 alloc_workqueue+0x378/0x450 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->scrub_lock); lock(&fs_devs->device_list_mutex); lock(&fs_info->scrub_lock); lock(cpu_hotplug_lock); *** DEADLOCK *** 2 locks held by btrfs/229626: #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630 #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 stack backtrace: CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? alloc_workqueue+0x378/0x450 cpus_read_lock+0x39/0xb0 ? alloc_workqueue+0x378/0x450 alloc_workqueue+0x378/0x450 ? rcu_read_lock_sched_held+0x52/0x80 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 ? start_transaction+0xd1/0x5d0 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ? do_sigaction+0x102/0x250 ? lockdep_hardirqs_on_prepare+0xca/0x160 ? _raw_spin_unlock_irq+0x24/0x30 ? trace_hardirqs_on+0x1c/0xe0 ? _raw_spin_unlock_irq+0x24/0x30 ? do_sigaction+0x102/0x250 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens because we're allocating the scrub workqueues under the scrub and device list mutex, which brings in a whole host of other dependencies. Because the work queue allocation is done with GFP_KERNEL, it can trigger reclaim, which can lead to a transaction commit, which in turns needs the device_list_mutex, it can lead to a deadlock. A different problem for which this fix is a solution. Fix this by moving the actual allocation outside of the scrub lock, and then only take the lock once we're ready to actually assign them to the fs_info. We'll now have to cleanup the workqueues in a few more places, so I've added a helper to do the refcount dance to safely free the workqueues. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 23:42:29 +08:00
scrub_wr_comp = btrfs_alloc_workqueue(fs_info, "scrubwrc", flags,
btrfs: Fix lockdep warning of wr_ctx->wr_lock in scrub_free_wr_ctx() lockdep report following warning in test: [25176.843958] ================================= [25176.844519] [ INFO: inconsistent lock state ] [25176.845047] 4.1.0-rc3 #22 Tainted: G W [25176.845591] --------------------------------- [25176.846153] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. [25176.846713] fsstress/26661 [HC0[0]:SC1[1]:HE1:SE0] takes: [25176.847246] (&wr_ctx->wr_lock){+.?...}, at: [<ffffffffa04cdc6d>] scrub_free_ctx+0x2d/0xf0 [btrfs] [25176.847838] {SOFTIRQ-ON-W} state was registered at: [25176.848396] [<ffffffff810bf460>] __lock_acquire+0x6a0/0xe10 [25176.848955] [<ffffffff810bfd1e>] lock_acquire+0xce/0x2c0 [25176.849491] [<ffffffff816489af>] mutex_lock_nested+0x7f/0x410 [25176.850029] [<ffffffffa04d04ff>] scrub_stripe+0x4df/0x1080 [btrfs] [25176.850575] [<ffffffffa04d11b1>] scrub_chunk.isra.19+0x111/0x130 [btrfs] [25176.851110] [<ffffffffa04d144c>] scrub_enumerate_chunks+0x27c/0x510 [btrfs] [25176.851660] [<ffffffffa04d3b87>] btrfs_scrub_dev+0x1c7/0x6c0 [btrfs] [25176.852189] [<ffffffffa04e918e>] btrfs_dev_replace_start+0x36e/0x450 [btrfs] [25176.852771] [<ffffffffa04a98e0>] btrfs_ioctl+0x1e10/0x2d20 [btrfs] [25176.853315] [<ffffffff8121c5b8>] do_vfs_ioctl+0x318/0x570 [25176.853868] [<ffffffff8121c851>] SyS_ioctl+0x41/0x80 [25176.854406] [<ffffffff8164da17>] system_call_fastpath+0x12/0x6f [25176.854935] irq event stamp: 51506 [25176.855511] hardirqs last enabled at (51506): [<ffffffff810d4ce5>] vprintk_emit+0x225/0x5e0 [25176.856059] hardirqs last disabled at (51505): [<ffffffff810d4b77>] vprintk_emit+0xb7/0x5e0 [25176.856642] softirqs last enabled at (50886): [<ffffffff81067a23>] __do_softirq+0x363/0x640 [25176.857184] softirqs last disabled at (50949): [<ffffffff8106804d>] irq_exit+0x10d/0x120 [25176.857746] other info that might help us debug this: [25176.858845] Possible unsafe locking scenario: [25176.859981] CPU0 [25176.860537] ---- [25176.861059] lock(&wr_ctx->wr_lock); [25176.861705] <Interrupt> [25176.862272] lock(&wr_ctx->wr_lock); [25176.862881] *** DEADLOCK *** Reason: Above warning is caused by: Interrupt -> bio_endio() -> ... -> scrub_put_ctx() -> scrub_free_ctx() *1 -> ... -> mutex_lock(&wr_ctx->wr_lock); scrub_put_ctx() is allowed to be called in end_bio interrupt, but in code design, it will never call scrub_free_ctx(sctx) in interrupe context(above *1), because btrfs_scrub_dev() get one additional reference of sctx->refs, which makes scrub_free_ctx() only called withine btrfs_scrub_dev(). Now the code runs out of our wish, because free sequence in scrub_pending_bio_dec() have a gap. Current code: -----------------------------------+----------------------------------- scrub_pending_bio_dec() | btrfs_scrub_dev -----------------------------------+----------------------------------- atomic_dec(&sctx->bios_in_flight); | wake_up(&sctx->list_wait); | | scrub_put_ctx() | -> atomic_dec_and_test(&sctx->refs) scrub_put_ctx(sctx); | -> atomic_dec_and_test(&sctx->refs)| -> scrub_free_ctx() | -----------------------------------+----------------------------------- We expected: -----------------------------------+----------------------------------- scrub_pending_bio_dec() | btrfs_scrub_dev -----------------------------------+----------------------------------- atomic_dec(&sctx->bios_in_flight); | wake_up(&sctx->list_wait); | scrub_put_ctx(sctx); | -> atomic_dec_and_test(&sctx->refs)| | scrub_put_ctx() | -> atomic_dec_and_test(&sctx->refs) | -> scrub_free_ctx() -----------------------------------+----------------------------------- Fix: Move scrub_pending_bio_dec() to a workqueue, to avoid this function run in interrupt context. Tested by check tracelog in debug. Changelog v1->v2: Use workqueue instead of adjust function call sequence in v1, because v1 will introduce a bug pointed out by: Filipe David Manana <fdmanana@gmail.com> Reported-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-06-04 20:09:15 +08:00
max_active, 2);
btrfs: allocate scrub workqueues outside of locks I got the following lockdep splat while testing: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00172-g021118712e59 #932 Not tainted ------------------------------------------------------ btrfs/229626 is trying to acquire lock: ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450 but task is already holding lock: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_scrub_dev+0x11c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #1 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 cpus_read_lock+0x39/0xb0 alloc_workqueue+0x378/0x450 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->scrub_lock); lock(&fs_devs->device_list_mutex); lock(&fs_info->scrub_lock); lock(cpu_hotplug_lock); *** DEADLOCK *** 2 locks held by btrfs/229626: #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630 #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 stack backtrace: CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? alloc_workqueue+0x378/0x450 cpus_read_lock+0x39/0xb0 ? alloc_workqueue+0x378/0x450 alloc_workqueue+0x378/0x450 ? rcu_read_lock_sched_held+0x52/0x80 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 ? start_transaction+0xd1/0x5d0 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ? do_sigaction+0x102/0x250 ? lockdep_hardirqs_on_prepare+0xca/0x160 ? _raw_spin_unlock_irq+0x24/0x30 ? trace_hardirqs_on+0x1c/0xe0 ? _raw_spin_unlock_irq+0x24/0x30 ? do_sigaction+0x102/0x250 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens because we're allocating the scrub workqueues under the scrub and device list mutex, which brings in a whole host of other dependencies. Because the work queue allocation is done with GFP_KERNEL, it can trigger reclaim, which can lead to a transaction commit, which in turns needs the device_list_mutex, it can lead to a deadlock. A different problem for which this fix is a solution. Fix this by moving the actual allocation outside of the scrub lock, and then only take the lock once we're ready to actually assign them to the fs_info. We'll now have to cleanup the workqueues in a few more places, so I've added a helper to do the refcount dance to safely free the workqueues. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 23:42:29 +08:00
if (!scrub_wr_comp)
goto fail_scrub_wr_completion_workers;
btrfs: allocate scrub workqueues outside of locks I got the following lockdep splat while testing: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00172-g021118712e59 #932 Not tainted ------------------------------------------------------ btrfs/229626 is trying to acquire lock: ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450 but task is already holding lock: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_scrub_dev+0x11c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #1 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 cpus_read_lock+0x39/0xb0 alloc_workqueue+0x378/0x450 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->scrub_lock); lock(&fs_devs->device_list_mutex); lock(&fs_info->scrub_lock); lock(cpu_hotplug_lock); *** DEADLOCK *** 2 locks held by btrfs/229626: #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630 #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 stack backtrace: CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? alloc_workqueue+0x378/0x450 cpus_read_lock+0x39/0xb0 ? alloc_workqueue+0x378/0x450 alloc_workqueue+0x378/0x450 ? rcu_read_lock_sched_held+0x52/0x80 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 ? start_transaction+0xd1/0x5d0 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ? do_sigaction+0x102/0x250 ? lockdep_hardirqs_on_prepare+0xca/0x160 ? _raw_spin_unlock_irq+0x24/0x30 ? trace_hardirqs_on+0x1c/0xe0 ? _raw_spin_unlock_irq+0x24/0x30 ? do_sigaction+0x102/0x250 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens because we're allocating the scrub workqueues under the scrub and device list mutex, which brings in a whole host of other dependencies. Because the work queue allocation is done with GFP_KERNEL, it can trigger reclaim, which can lead to a transaction commit, which in turns needs the device_list_mutex, it can lead to a deadlock. A different problem for which this fix is a solution. Fix this by moving the actual allocation outside of the scrub lock, and then only take the lock once we're ready to actually assign them to the fs_info. We'll now have to cleanup the workqueues in a few more places, so I've added a helper to do the refcount dance to safely free the workqueues. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 23:42:29 +08:00
scrub_parity = btrfs_alloc_workqueue(fs_info, "scrubparity", flags,
max_active, 2);
if (!scrub_parity)
goto fail_scrub_parity_workers;
mutex_lock(&fs_info->scrub_lock);
if (refcount_read(&fs_info->scrub_workers_refcnt) == 0) {
ASSERT(fs_info->scrub_workers == NULL &&
fs_info->scrub_wr_completion_workers == NULL &&
fs_info->scrub_parity_workers == NULL);
fs_info->scrub_workers = scrub_workers;
fs_info->scrub_wr_completion_workers = scrub_wr_comp;
fs_info->scrub_parity_workers = scrub_parity;
refcount_set(&fs_info->scrub_workers_refcnt, 1);
btrfs: allocate scrub workqueues outside of locks I got the following lockdep splat while testing: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00172-g021118712e59 #932 Not tainted ------------------------------------------------------ btrfs/229626 is trying to acquire lock: ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450 but task is already holding lock: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_scrub_dev+0x11c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #1 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 cpus_read_lock+0x39/0xb0 alloc_workqueue+0x378/0x450 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->scrub_lock); lock(&fs_devs->device_list_mutex); lock(&fs_info->scrub_lock); lock(cpu_hotplug_lock); *** DEADLOCK *** 2 locks held by btrfs/229626: #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630 #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 stack backtrace: CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? alloc_workqueue+0x378/0x450 cpus_read_lock+0x39/0xb0 ? alloc_workqueue+0x378/0x450 alloc_workqueue+0x378/0x450 ? rcu_read_lock_sched_held+0x52/0x80 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 ? start_transaction+0xd1/0x5d0 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ? do_sigaction+0x102/0x250 ? lockdep_hardirqs_on_prepare+0xca/0x160 ? _raw_spin_unlock_irq+0x24/0x30 ? trace_hardirqs_on+0x1c/0xe0 ? _raw_spin_unlock_irq+0x24/0x30 ? do_sigaction+0x102/0x250 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens because we're allocating the scrub workqueues under the scrub and device list mutex, which brings in a whole host of other dependencies. Because the work queue allocation is done with GFP_KERNEL, it can trigger reclaim, which can lead to a transaction commit, which in turns needs the device_list_mutex, it can lead to a deadlock. A different problem for which this fix is a solution. Fix this by moving the actual allocation outside of the scrub lock, and then only take the lock once we're ready to actually assign them to the fs_info. We'll now have to cleanup the workqueues in a few more places, so I've added a helper to do the refcount dance to safely free the workqueues. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 23:42:29 +08:00
mutex_unlock(&fs_info->scrub_lock);
return 0;
}
btrfs: allocate scrub workqueues outside of locks I got the following lockdep splat while testing: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00172-g021118712e59 #932 Not tainted ------------------------------------------------------ btrfs/229626 is trying to acquire lock: ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450 but task is already holding lock: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_scrub_dev+0x11c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #1 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 cpus_read_lock+0x39/0xb0 alloc_workqueue+0x378/0x450 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->scrub_lock); lock(&fs_devs->device_list_mutex); lock(&fs_info->scrub_lock); lock(cpu_hotplug_lock); *** DEADLOCK *** 2 locks held by btrfs/229626: #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630 #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 stack backtrace: CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? alloc_workqueue+0x378/0x450 cpus_read_lock+0x39/0xb0 ? alloc_workqueue+0x378/0x450 alloc_workqueue+0x378/0x450 ? rcu_read_lock_sched_held+0x52/0x80 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 ? start_transaction+0xd1/0x5d0 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ? do_sigaction+0x102/0x250 ? lockdep_hardirqs_on_prepare+0xca/0x160 ? _raw_spin_unlock_irq+0x24/0x30 ? trace_hardirqs_on+0x1c/0xe0 ? _raw_spin_unlock_irq+0x24/0x30 ? do_sigaction+0x102/0x250 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens because we're allocating the scrub workqueues under the scrub and device list mutex, which brings in a whole host of other dependencies. Because the work queue allocation is done with GFP_KERNEL, it can trigger reclaim, which can lead to a transaction commit, which in turns needs the device_list_mutex, it can lead to a deadlock. A different problem for which this fix is a solution. Fix this by moving the actual allocation outside of the scrub lock, and then only take the lock once we're ready to actually assign them to the fs_info. We'll now have to cleanup the workqueues in a few more places, so I've added a helper to do the refcount dance to safely free the workqueues. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 23:42:29 +08:00
/* Other thread raced in and created the workers for us */
refcount_inc(&fs_info->scrub_workers_refcnt);
mutex_unlock(&fs_info->scrub_lock);
btrfs: allocate scrub workqueues outside of locks I got the following lockdep splat while testing: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00172-g021118712e59 #932 Not tainted ------------------------------------------------------ btrfs/229626 is trying to acquire lock: ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450 but task is already holding lock: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_scrub_dev+0x11c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #1 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 cpus_read_lock+0x39/0xb0 alloc_workqueue+0x378/0x450 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->scrub_lock); lock(&fs_devs->device_list_mutex); lock(&fs_info->scrub_lock); lock(cpu_hotplug_lock); *** DEADLOCK *** 2 locks held by btrfs/229626: #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630 #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 stack backtrace: CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? alloc_workqueue+0x378/0x450 cpus_read_lock+0x39/0xb0 ? alloc_workqueue+0x378/0x450 alloc_workqueue+0x378/0x450 ? rcu_read_lock_sched_held+0x52/0x80 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 ? start_transaction+0xd1/0x5d0 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ? do_sigaction+0x102/0x250 ? lockdep_hardirqs_on_prepare+0xca/0x160 ? _raw_spin_unlock_irq+0x24/0x30 ? trace_hardirqs_on+0x1c/0xe0 ? _raw_spin_unlock_irq+0x24/0x30 ? do_sigaction+0x102/0x250 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens because we're allocating the scrub workqueues under the scrub and device list mutex, which brings in a whole host of other dependencies. Because the work queue allocation is done with GFP_KERNEL, it can trigger reclaim, which can lead to a transaction commit, which in turns needs the device_list_mutex, it can lead to a deadlock. A different problem for which this fix is a solution. Fix this by moving the actual allocation outside of the scrub lock, and then only take the lock once we're ready to actually assign them to the fs_info. We'll now have to cleanup the workqueues in a few more places, so I've added a helper to do the refcount dance to safely free the workqueues. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 23:42:29 +08:00
ret = 0;
btrfs_destroy_workqueue(scrub_parity);
fail_scrub_parity_workers:
btrfs: allocate scrub workqueues outside of locks I got the following lockdep splat while testing: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00172-g021118712e59 #932 Not tainted ------------------------------------------------------ btrfs/229626 is trying to acquire lock: ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450 but task is already holding lock: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_scrub_dev+0x11c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #1 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 cpus_read_lock+0x39/0xb0 alloc_workqueue+0x378/0x450 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->scrub_lock); lock(&fs_devs->device_list_mutex); lock(&fs_info->scrub_lock); lock(cpu_hotplug_lock); *** DEADLOCK *** 2 locks held by btrfs/229626: #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630 #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 stack backtrace: CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? alloc_workqueue+0x378/0x450 cpus_read_lock+0x39/0xb0 ? alloc_workqueue+0x378/0x450 alloc_workqueue+0x378/0x450 ? rcu_read_lock_sched_held+0x52/0x80 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 ? start_transaction+0xd1/0x5d0 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ? do_sigaction+0x102/0x250 ? lockdep_hardirqs_on_prepare+0xca/0x160 ? _raw_spin_unlock_irq+0x24/0x30 ? trace_hardirqs_on+0x1c/0xe0 ? _raw_spin_unlock_irq+0x24/0x30 ? do_sigaction+0x102/0x250 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens because we're allocating the scrub workqueues under the scrub and device list mutex, which brings in a whole host of other dependencies. Because the work queue allocation is done with GFP_KERNEL, it can trigger reclaim, which can lead to a transaction commit, which in turns needs the device_list_mutex, it can lead to a deadlock. A different problem for which this fix is a solution. Fix this by moving the actual allocation outside of the scrub lock, and then only take the lock once we're ready to actually assign them to the fs_info. We'll now have to cleanup the workqueues in a few more places, so I've added a helper to do the refcount dance to safely free the workqueues. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 23:42:29 +08:00
btrfs_destroy_workqueue(scrub_wr_comp);
fail_scrub_wr_completion_workers:
btrfs: allocate scrub workqueues outside of locks I got the following lockdep splat while testing: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00172-g021118712e59 #932 Not tainted ------------------------------------------------------ btrfs/229626 is trying to acquire lock: ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450 but task is already holding lock: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_scrub_dev+0x11c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #1 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 cpus_read_lock+0x39/0xb0 alloc_workqueue+0x378/0x450 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->scrub_lock); lock(&fs_devs->device_list_mutex); lock(&fs_info->scrub_lock); lock(cpu_hotplug_lock); *** DEADLOCK *** 2 locks held by btrfs/229626: #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630 #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 stack backtrace: CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? alloc_workqueue+0x378/0x450 cpus_read_lock+0x39/0xb0 ? alloc_workqueue+0x378/0x450 alloc_workqueue+0x378/0x450 ? rcu_read_lock_sched_held+0x52/0x80 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 ? start_transaction+0xd1/0x5d0 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ? do_sigaction+0x102/0x250 ? lockdep_hardirqs_on_prepare+0xca/0x160 ? _raw_spin_unlock_irq+0x24/0x30 ? trace_hardirqs_on+0x1c/0xe0 ? _raw_spin_unlock_irq+0x24/0x30 ? do_sigaction+0x102/0x250 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens because we're allocating the scrub workqueues under the scrub and device list mutex, which brings in a whole host of other dependencies. Because the work queue allocation is done with GFP_KERNEL, it can trigger reclaim, which can lead to a transaction commit, which in turns needs the device_list_mutex, it can lead to a deadlock. A different problem for which this fix is a solution. Fix this by moving the actual allocation outside of the scrub lock, and then only take the lock once we're ready to actually assign them to the fs_info. We'll now have to cleanup the workqueues in a few more places, so I've added a helper to do the refcount dance to safely free the workqueues. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 23:42:29 +08:00
btrfs_destroy_workqueue(scrub_workers);
fail_scrub_workers:
btrfs: allocate scrub workqueues outside of locks I got the following lockdep splat while testing: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00172-g021118712e59 #932 Not tainted ------------------------------------------------------ btrfs/229626 is trying to acquire lock: ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450 but task is already holding lock: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_scrub_dev+0x11c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #1 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 cpus_read_lock+0x39/0xb0 alloc_workqueue+0x378/0x450 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->scrub_lock); lock(&fs_devs->device_list_mutex); lock(&fs_info->scrub_lock); lock(cpu_hotplug_lock); *** DEADLOCK *** 2 locks held by btrfs/229626: #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630 #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 stack backtrace: CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? alloc_workqueue+0x378/0x450 cpus_read_lock+0x39/0xb0 ? alloc_workqueue+0x378/0x450 alloc_workqueue+0x378/0x450 ? rcu_read_lock_sched_held+0x52/0x80 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 ? start_transaction+0xd1/0x5d0 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ? do_sigaction+0x102/0x250 ? lockdep_hardirqs_on_prepare+0xca/0x160 ? _raw_spin_unlock_irq+0x24/0x30 ? trace_hardirqs_on+0x1c/0xe0 ? _raw_spin_unlock_irq+0x24/0x30 ? do_sigaction+0x102/0x250 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens because we're allocating the scrub workqueues under the scrub and device list mutex, which brings in a whole host of other dependencies. Because the work queue allocation is done with GFP_KERNEL, it can trigger reclaim, which can lead to a transaction commit, which in turns needs the device_list_mutex, it can lead to a deadlock. A different problem for which this fix is a solution. Fix this by moving the actual allocation outside of the scrub lock, and then only take the lock once we're ready to actually assign them to the fs_info. We'll now have to cleanup the workqueues in a few more places, so I've added a helper to do the refcount dance to safely free the workqueues. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 23:42:29 +08:00
return ret;
}
int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
u64 end, struct btrfs_scrub_progress *progress,
int readonly, int is_dev_replace)
{
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
struct scrub_ctx *sctx;
int ret;
struct btrfs_device *dev;
unsigned int nofs_flag;
if (btrfs_fs_closing(fs_info))
return -EAGAIN;
if (fs_info->nodesize > BTRFS_STRIPE_LEN) {
/*
* in this case scrub is unable to calculate the checksum
* the way scrub is implemented. Do not handle this
* situation at all because it won't ever happen.
*/
btrfs_err(fs_info,
"scrub: size assumption nodesize <= BTRFS_STRIPE_LEN (%d <= %d) fails",
fs_info->nodesize,
BTRFS_STRIPE_LEN);
return -EINVAL;
}
if (fs_info->nodesize >
PAGE_SIZE * SCRUB_MAX_PAGES_PER_BLOCK ||
fs_info->sectorsize > PAGE_SIZE * SCRUB_MAX_PAGES_PER_BLOCK) {
/*
* would exhaust the array bounds of pagev member in
* struct scrub_block
*/
btrfs_err(fs_info,
"scrub: size assumption nodesize and sectorsize <= SCRUB_MAX_PAGES_PER_BLOCK (%d <= %d && %d <= %d) fails",
fs_info->nodesize,
SCRUB_MAX_PAGES_PER_BLOCK,
fs_info->sectorsize,
SCRUB_MAX_PAGES_PER_BLOCK);
return -EINVAL;
}
/* Allocate outside of device_list_mutex */
sctx = scrub_setup_ctx(fs_info, is_dev_replace);
if (IS_ERR(sctx))
return PTR_ERR(sctx);
btrfs: allocate scrub workqueues outside of locks I got the following lockdep splat while testing: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00172-g021118712e59 #932 Not tainted ------------------------------------------------------ btrfs/229626 is trying to acquire lock: ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450 but task is already holding lock: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_scrub_dev+0x11c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #1 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 cpus_read_lock+0x39/0xb0 alloc_workqueue+0x378/0x450 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->scrub_lock); lock(&fs_devs->device_list_mutex); lock(&fs_info->scrub_lock); lock(cpu_hotplug_lock); *** DEADLOCK *** 2 locks held by btrfs/229626: #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630 #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 stack backtrace: CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? alloc_workqueue+0x378/0x450 cpus_read_lock+0x39/0xb0 ? alloc_workqueue+0x378/0x450 alloc_workqueue+0x378/0x450 ? rcu_read_lock_sched_held+0x52/0x80 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 ? start_transaction+0xd1/0x5d0 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ? do_sigaction+0x102/0x250 ? lockdep_hardirqs_on_prepare+0xca/0x160 ? _raw_spin_unlock_irq+0x24/0x30 ? trace_hardirqs_on+0x1c/0xe0 ? _raw_spin_unlock_irq+0x24/0x30 ? do_sigaction+0x102/0x250 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens because we're allocating the scrub workqueues under the scrub and device list mutex, which brings in a whole host of other dependencies. Because the work queue allocation is done with GFP_KERNEL, it can trigger reclaim, which can lead to a transaction commit, which in turns needs the device_list_mutex, it can lead to a deadlock. A different problem for which this fix is a solution. Fix this by moving the actual allocation outside of the scrub lock, and then only take the lock once we're ready to actually assign them to the fs_info. We'll now have to cleanup the workqueues in a few more places, so I've added a helper to do the refcount dance to safely free the workqueues. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 23:42:29 +08:00
ret = scrub_workers_get(fs_info, is_dev_replace);
if (ret)
goto out_free_ctx;
mutex_lock(&fs_info->fs_devices->device_list_mutex);
dev = btrfs_find_device(fs_info->fs_devices, devid, NULL, NULL);
if (!dev || (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state) &&
!is_dev_replace)) {
mutex_unlock(&fs_info->fs_devices->device_list_mutex);
ret = -ENODEV;
btrfs: allocate scrub workqueues outside of locks I got the following lockdep splat while testing: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00172-g021118712e59 #932 Not tainted ------------------------------------------------------ btrfs/229626 is trying to acquire lock: ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450 but task is already holding lock: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_scrub_dev+0x11c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #1 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 cpus_read_lock+0x39/0xb0 alloc_workqueue+0x378/0x450 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->scrub_lock); lock(&fs_devs->device_list_mutex); lock(&fs_info->scrub_lock); lock(cpu_hotplug_lock); *** DEADLOCK *** 2 locks held by btrfs/229626: #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630 #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 stack backtrace: CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? alloc_workqueue+0x378/0x450 cpus_read_lock+0x39/0xb0 ? alloc_workqueue+0x378/0x450 alloc_workqueue+0x378/0x450 ? rcu_read_lock_sched_held+0x52/0x80 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 ? start_transaction+0xd1/0x5d0 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ? do_sigaction+0x102/0x250 ? lockdep_hardirqs_on_prepare+0xca/0x160 ? _raw_spin_unlock_irq+0x24/0x30 ? trace_hardirqs_on+0x1c/0xe0 ? _raw_spin_unlock_irq+0x24/0x30 ? do_sigaction+0x102/0x250 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens because we're allocating the scrub workqueues under the scrub and device list mutex, which brings in a whole host of other dependencies. Because the work queue allocation is done with GFP_KERNEL, it can trigger reclaim, which can lead to a transaction commit, which in turns needs the device_list_mutex, it can lead to a deadlock. A different problem for which this fix is a solution. Fix this by moving the actual allocation outside of the scrub lock, and then only take the lock once we're ready to actually assign them to the fs_info. We'll now have to cleanup the workqueues in a few more places, so I've added a helper to do the refcount dance to safely free the workqueues. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 23:42:29 +08:00
goto out;
}
if (!is_dev_replace && !readonly &&
!test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state)) {
mutex_unlock(&fs_info->fs_devices->device_list_mutex);
btrfs_err_in_rcu(fs_info,
"scrub on devid %llu: filesystem on %s is not writable",
devid, rcu_str_deref(dev->name));
ret = -EROFS;
btrfs: allocate scrub workqueues outside of locks I got the following lockdep splat while testing: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00172-g021118712e59 #932 Not tainted ------------------------------------------------------ btrfs/229626 is trying to acquire lock: ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450 but task is already holding lock: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_scrub_dev+0x11c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #1 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 cpus_read_lock+0x39/0xb0 alloc_workqueue+0x378/0x450 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->scrub_lock); lock(&fs_devs->device_list_mutex); lock(&fs_info->scrub_lock); lock(cpu_hotplug_lock); *** DEADLOCK *** 2 locks held by btrfs/229626: #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630 #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 stack backtrace: CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? alloc_workqueue+0x378/0x450 cpus_read_lock+0x39/0xb0 ? alloc_workqueue+0x378/0x450 alloc_workqueue+0x378/0x450 ? rcu_read_lock_sched_held+0x52/0x80 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 ? start_transaction+0xd1/0x5d0 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ? do_sigaction+0x102/0x250 ? lockdep_hardirqs_on_prepare+0xca/0x160 ? _raw_spin_unlock_irq+0x24/0x30 ? trace_hardirqs_on+0x1c/0xe0 ? _raw_spin_unlock_irq+0x24/0x30 ? do_sigaction+0x102/0x250 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens because we're allocating the scrub workqueues under the scrub and device list mutex, which brings in a whole host of other dependencies. Because the work queue allocation is done with GFP_KERNEL, it can trigger reclaim, which can lead to a transaction commit, which in turns needs the device_list_mutex, it can lead to a deadlock. A different problem for which this fix is a solution. Fix this by moving the actual allocation outside of the scrub lock, and then only take the lock once we're ready to actually assign them to the fs_info. We'll now have to cleanup the workqueues in a few more places, so I've added a helper to do the refcount dance to safely free the workqueues. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 23:42:29 +08:00
goto out;
}
mutex_lock(&fs_info->scrub_lock);
if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &dev->dev_state) ||
test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &dev->dev_state)) {
mutex_unlock(&fs_info->scrub_lock);
mutex_unlock(&fs_info->fs_devices->device_list_mutex);
ret = -EIO;
btrfs: allocate scrub workqueues outside of locks I got the following lockdep splat while testing: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00172-g021118712e59 #932 Not tainted ------------------------------------------------------ btrfs/229626 is trying to acquire lock: ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450 but task is already holding lock: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_scrub_dev+0x11c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #1 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 cpus_read_lock+0x39/0xb0 alloc_workqueue+0x378/0x450 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->scrub_lock); lock(&fs_devs->device_list_mutex); lock(&fs_info->scrub_lock); lock(cpu_hotplug_lock); *** DEADLOCK *** 2 locks held by btrfs/229626: #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630 #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 stack backtrace: CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? alloc_workqueue+0x378/0x450 cpus_read_lock+0x39/0xb0 ? alloc_workqueue+0x378/0x450 alloc_workqueue+0x378/0x450 ? rcu_read_lock_sched_held+0x52/0x80 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 ? start_transaction+0xd1/0x5d0 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ? do_sigaction+0x102/0x250 ? lockdep_hardirqs_on_prepare+0xca/0x160 ? _raw_spin_unlock_irq+0x24/0x30 ? trace_hardirqs_on+0x1c/0xe0 ? _raw_spin_unlock_irq+0x24/0x30 ? do_sigaction+0x102/0x250 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens because we're allocating the scrub workqueues under the scrub and device list mutex, which brings in a whole host of other dependencies. Because the work queue allocation is done with GFP_KERNEL, it can trigger reclaim, which can lead to a transaction commit, which in turns needs the device_list_mutex, it can lead to a deadlock. A different problem for which this fix is a solution. Fix this by moving the actual allocation outside of the scrub lock, and then only take the lock once we're ready to actually assign them to the fs_info. We'll now have to cleanup the workqueues in a few more places, so I've added a helper to do the refcount dance to safely free the workqueues. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 23:42:29 +08:00
goto out;
}
down_read(&fs_info->dev_replace.rwsem);
if (dev->scrub_ctx ||
(!is_dev_replace &&
btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))) {
up_read(&fs_info->dev_replace.rwsem);
mutex_unlock(&fs_info->scrub_lock);
mutex_unlock(&fs_info->fs_devices->device_list_mutex);
ret = -EINPROGRESS;
btrfs: allocate scrub workqueues outside of locks I got the following lockdep splat while testing: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00172-g021118712e59 #932 Not tainted ------------------------------------------------------ btrfs/229626 is trying to acquire lock: ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450 but task is already holding lock: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_scrub_dev+0x11c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #1 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 cpus_read_lock+0x39/0xb0 alloc_workqueue+0x378/0x450 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->scrub_lock); lock(&fs_devs->device_list_mutex); lock(&fs_info->scrub_lock); lock(cpu_hotplug_lock); *** DEADLOCK *** 2 locks held by btrfs/229626: #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630 #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 stack backtrace: CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? alloc_workqueue+0x378/0x450 cpus_read_lock+0x39/0xb0 ? alloc_workqueue+0x378/0x450 alloc_workqueue+0x378/0x450 ? rcu_read_lock_sched_held+0x52/0x80 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 ? start_transaction+0xd1/0x5d0 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ? do_sigaction+0x102/0x250 ? lockdep_hardirqs_on_prepare+0xca/0x160 ? _raw_spin_unlock_irq+0x24/0x30 ? trace_hardirqs_on+0x1c/0xe0 ? _raw_spin_unlock_irq+0x24/0x30 ? do_sigaction+0x102/0x250 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens because we're allocating the scrub workqueues under the scrub and device list mutex, which brings in a whole host of other dependencies. Because the work queue allocation is done with GFP_KERNEL, it can trigger reclaim, which can lead to a transaction commit, which in turns needs the device_list_mutex, it can lead to a deadlock. A different problem for which this fix is a solution. Fix this by moving the actual allocation outside of the scrub lock, and then only take the lock once we're ready to actually assign them to the fs_info. We'll now have to cleanup the workqueues in a few more places, so I've added a helper to do the refcount dance to safely free the workqueues. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 23:42:29 +08:00
goto out;
}
up_read(&fs_info->dev_replace.rwsem);
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
sctx->readonly = readonly;
dev->scrub_ctx = sctx;
mutex_unlock(&fs_info->fs_devices->device_list_mutex);
/*
* checking @scrub_pause_req here, we can avoid
* race between committing transaction and scrubbing.
*/
__scrub_blocked_if_needed(fs_info);
atomic_inc(&fs_info->scrubs_running);
mutex_unlock(&fs_info->scrub_lock);
/*
* In order to avoid deadlock with reclaim when there is a transaction
* trying to pause scrub, make sure we use GFP_NOFS for all the
* allocations done at btrfs_scrub_pages() and scrub_pages_for_parity()
* invoked by our callees. The pausing request is done when the
* transaction commit starts, and it blocks the transaction until scrub
* is paused (done at specific points at scrub_stripe() or right above
* before incrementing fs_info->scrubs_running).
*/
nofs_flag = memalloc_nofs_save();
if (!is_dev_replace) {
btrfs_info(fs_info, "scrub: started on devid %llu", devid);
/*
* by holding device list mutex, we can
* kick off writing super in log tree sync.
*/
mutex_lock(&fs_info->fs_devices->device_list_mutex);
ret = scrub_supers(sctx, dev);
mutex_unlock(&fs_info->fs_devices->device_list_mutex);
}
if (!ret)
ret = scrub_enumerate_chunks(sctx, dev, start, end);
memalloc_nofs_restore(nofs_flag);
wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
atomic_dec(&fs_info->scrubs_running);
wake_up(&fs_info->scrub_pause_wait);
wait_event(sctx->list_wait, atomic_read(&sctx->workers_pending) == 0);
if (progress)
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
memcpy(progress, &sctx->stat, sizeof(*progress));
if (!is_dev_replace)
btrfs_info(fs_info, "scrub: %s on devid %llu with status: %d",
ret ? "not finished" : "finished", devid, ret);
mutex_lock(&fs_info->scrub_lock);
dev->scrub_ctx = NULL;
mutex_unlock(&fs_info->scrub_lock);
btrfs: allocate scrub workqueues outside of locks I got the following lockdep splat while testing: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00172-g021118712e59 #932 Not tainted ------------------------------------------------------ btrfs/229626 is trying to acquire lock: ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450 but task is already holding lock: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_scrub_dev+0x11c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #1 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 cpus_read_lock+0x39/0xb0 alloc_workqueue+0x378/0x450 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->scrub_lock); lock(&fs_devs->device_list_mutex); lock(&fs_info->scrub_lock); lock(cpu_hotplug_lock); *** DEADLOCK *** 2 locks held by btrfs/229626: #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630 #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 stack backtrace: CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? alloc_workqueue+0x378/0x450 cpus_read_lock+0x39/0xb0 ? alloc_workqueue+0x378/0x450 alloc_workqueue+0x378/0x450 ? rcu_read_lock_sched_held+0x52/0x80 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 ? start_transaction+0xd1/0x5d0 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ? do_sigaction+0x102/0x250 ? lockdep_hardirqs_on_prepare+0xca/0x160 ? _raw_spin_unlock_irq+0x24/0x30 ? trace_hardirqs_on+0x1c/0xe0 ? _raw_spin_unlock_irq+0x24/0x30 ? do_sigaction+0x102/0x250 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens because we're allocating the scrub workqueues under the scrub and device list mutex, which brings in a whole host of other dependencies. Because the work queue allocation is done with GFP_KERNEL, it can trigger reclaim, which can lead to a transaction commit, which in turns needs the device_list_mutex, it can lead to a deadlock. A different problem for which this fix is a solution. Fix this by moving the actual allocation outside of the scrub lock, and then only take the lock once we're ready to actually assign them to the fs_info. We'll now have to cleanup the workqueues in a few more places, so I've added a helper to do the refcount dance to safely free the workqueues. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 23:42:29 +08:00
scrub_workers_put(fs_info);
Btrfs: scrub, fix sleep in atomic context My previous patch "Btrfs: fix scrub race leading to use-after-free" introduced the possibility to sleep in an atomic context, which happens when the scrub_lock mutex is held at the time scrub_pending_bio_dec() is called - this function can be called under an atomic context. Chris ran into this in a debug kernel which gave the following trace: [ 1928.950319] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:621 [ 1928.967334] in_atomic(): 1, irqs_disabled(): 0, pid: 149670, name: fsstress [ 1928.981324] INFO: lockdep is turned off. [ 1928.989244] CPU: 24 PID: 149670 Comm: fsstress Tainted: G W 3.19.0-rc7-mason+ #41 [ 1929.006418] Hardware name: ZTSYSTEMS Echo Ridge T4 /A9DRPF-10D, BIOS 1.07 05/10/2012 [ 1929.022207] ffffffff81a22cf8 ffff881076e03b78 ffffffff816b8dd9 ffff881076e03b78 [ 1929.037267] ffff880d8e828710 ffff881076e03ba8 ffffffff810856c4 ffff881076e03bc8 [ 1929.052315] 0000000000000000 000000000000026d ffffffff81a22cf8 ffff881076e03bd8 [ 1929.067381] Call Trace: [ 1929.072344] <IRQ> [<ffffffff816b8dd9>] dump_stack+0x4f/0x6e [ 1929.083968] [<ffffffff810856c4>] ___might_sleep+0x174/0x230 [ 1929.095352] [<ffffffff810857d2>] __might_sleep+0x52/0x90 [ 1929.106223] [<ffffffff816bb68f>] mutex_lock_nested+0x2f/0x3b0 [ 1929.117951] [<ffffffff810ab37d>] ? trace_hardirqs_on+0xd/0x10 [ 1929.129708] [<ffffffffa05dc838>] scrub_pending_bio_dec+0x38/0x70 [btrfs] [ 1929.143370] [<ffffffffa05dd0e0>] scrub_parity_bio_endio+0x50/0x70 [btrfs] [ 1929.157191] [<ffffffff812fa603>] bio_endio+0x53/0xa0 [ 1929.167382] [<ffffffffa05f96bc>] rbio_orig_end_io+0x7c/0xa0 [btrfs] [ 1929.180161] [<ffffffffa05f97ba>] raid_write_parity_end_io+0x5a/0x80 [btrfs] [ 1929.194318] [<ffffffff812fa603>] bio_endio+0x53/0xa0 [ 1929.204496] [<ffffffff8130401b>] blk_update_request+0x1eb/0x450 [ 1929.216569] [<ffffffff81096e58>] ? trigger_load_balance+0x78/0x500 [ 1929.229176] [<ffffffff8144c74d>] scsi_end_request+0x3d/0x1f0 [ 1929.240740] [<ffffffff8144ccac>] scsi_io_completion+0xac/0x5b0 [ 1929.252654] [<ffffffff81441c50>] scsi_finish_command+0xf0/0x150 [ 1929.264725] [<ffffffff8144d317>] scsi_softirq_done+0x147/0x170 [ 1929.276635] [<ffffffff8130ace6>] blk_done_softirq+0x86/0xa0 [ 1929.288014] [<ffffffff8105d92e>] __do_softirq+0xde/0x600 [ 1929.298885] [<ffffffff8105df6d>] irq_exit+0xbd/0xd0 (...) Fix this by using a reference count on the scrub context structure instead of locking the scrub_lock mutex. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-02-10 05:14:24 +08:00
scrub_put_ctx(sctx);
return ret;
btrfs: allocate scrub workqueues outside of locks I got the following lockdep splat while testing: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00172-g021118712e59 #932 Not tainted ------------------------------------------------------ btrfs/229626 is trying to acquire lock: ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450 but task is already holding lock: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_scrub_dev+0x11c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_run_dev_stats+0x49/0x480 commit_cowonly_roots+0xb5/0x2a0 btrfs_commit_transaction+0x516/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_commit_transaction+0x4bb/0xa60 sync_filesystem+0x6b/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0xe/0x30 btrfs_kill_super+0x12/0x20 deactivate_locked_super+0x29/0x60 cleanup_mnt+0xb8/0x140 task_work_run+0x6d/0xb0 __prepare_exit_to_usermode+0x1cc/0x1e0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_record_root_in_trans+0x43/0x70 start_transaction+0xd1/0x5d0 btrfs_dirty_inode+0x42/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 perf_read+0x141/0x2c0 vfs_read+0xad/0x1b0 ksys_read+0x5f/0xe0 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&cpuctx_mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x88/0x150 perf_event_init+0x1db/0x20b start_kernel+0x3ae/0x53c secondary_startup_64+0xa4/0xb0 -> #1 (pmus_lock){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 perf_event_init_cpu+0x4f/0x150 cpuhp_invoke_callback+0xb1/0x900 _cpu_up.constprop.26+0x9f/0x130 cpu_up+0x7b/0xc0 bringup_nonboot_cpus+0x4f/0x60 smp_init+0x26/0x71 kernel_init_freeable+0x110/0x258 kernel_init+0xa/0x103 ret_from_fork+0x1f/0x30 -> #0 (cpu_hotplug_lock){++++}-{0:0}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 cpus_read_lock+0x39/0xb0 alloc_workqueue+0x378/0x450 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->scrub_lock); lock(&fs_devs->device_list_mutex); lock(&fs_info->scrub_lock); lock(cpu_hotplug_lock); *** DEADLOCK *** 2 locks held by btrfs/229626: #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630 #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630 stack backtrace: CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? alloc_workqueue+0x378/0x450 cpus_read_lock+0x39/0xb0 ? alloc_workqueue+0x378/0x450 alloc_workqueue+0x378/0x450 ? rcu_read_lock_sched_held+0x52/0x80 __btrfs_alloc_workqueue+0x15d/0x200 btrfs_alloc_workqueue+0x51/0x160 scrub_workers_get+0x5a/0x170 btrfs_scrub_dev+0x18c/0x630 ? start_transaction+0xd1/0x5d0 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4 btrfs_ioctl+0x2799/0x30a0 ? do_sigaction+0x102/0x250 ? lockdep_hardirqs_on_prepare+0xca/0x160 ? _raw_spin_unlock_irq+0x24/0x30 ? trace_hardirqs_on+0x1c/0xe0 ? _raw_spin_unlock_irq+0x24/0x30 ? do_sigaction+0x102/0x250 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens because we're allocating the scrub workqueues under the scrub and device list mutex, which brings in a whole host of other dependencies. Because the work queue allocation is done with GFP_KERNEL, it can trigger reclaim, which can lead to a transaction commit, which in turns needs the device_list_mutex, it can lead to a deadlock. A different problem for which this fix is a solution. Fix this by moving the actual allocation outside of the scrub lock, and then only take the lock once we're ready to actually assign them to the fs_info. We'll now have to cleanup the workqueues in a few more places, so I've added a helper to do the refcount dance to safely free the workqueues. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 23:42:29 +08:00
out:
scrub_workers_put(fs_info);
out_free_ctx:
scrub_free_ctx(sctx);
return ret;
}
void btrfs_scrub_pause(struct btrfs_fs_info *fs_info)
{
mutex_lock(&fs_info->scrub_lock);
atomic_inc(&fs_info->scrub_pause_req);
while (atomic_read(&fs_info->scrubs_paused) !=
atomic_read(&fs_info->scrubs_running)) {
mutex_unlock(&fs_info->scrub_lock);
wait_event(fs_info->scrub_pause_wait,
atomic_read(&fs_info->scrubs_paused) ==
atomic_read(&fs_info->scrubs_running));
mutex_lock(&fs_info->scrub_lock);
}
mutex_unlock(&fs_info->scrub_lock);
}
void btrfs_scrub_continue(struct btrfs_fs_info *fs_info)
{
atomic_dec(&fs_info->scrub_pause_req);
wake_up(&fs_info->scrub_pause_wait);
}
int btrfs_scrub_cancel(struct btrfs_fs_info *fs_info)
{
mutex_lock(&fs_info->scrub_lock);
if (!atomic_read(&fs_info->scrubs_running)) {
mutex_unlock(&fs_info->scrub_lock);
return -ENOTCONN;
}
atomic_inc(&fs_info->scrub_cancel_req);
while (atomic_read(&fs_info->scrubs_running)) {
mutex_unlock(&fs_info->scrub_lock);
wait_event(fs_info->scrub_pause_wait,
atomic_read(&fs_info->scrubs_running) == 0);
mutex_lock(&fs_info->scrub_lock);
}
atomic_dec(&fs_info->scrub_cancel_req);
mutex_unlock(&fs_info->scrub_lock);
return 0;
}
int btrfs_scrub_cancel_dev(struct btrfs_device *dev)
{
struct btrfs_fs_info *fs_info = dev->fs_info;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
struct scrub_ctx *sctx;
mutex_lock(&fs_info->scrub_lock);
sctx = dev->scrub_ctx;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
if (!sctx) {
mutex_unlock(&fs_info->scrub_lock);
return -ENOTCONN;
}
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
atomic_inc(&sctx->cancel_req);
while (dev->scrub_ctx) {
mutex_unlock(&fs_info->scrub_lock);
wait_event(fs_info->scrub_pause_wait,
dev->scrub_ctx == NULL);
mutex_lock(&fs_info->scrub_lock);
}
mutex_unlock(&fs_info->scrub_lock);
return 0;
}
int btrfs_scrub_progress(struct btrfs_fs_info *fs_info, u64 devid,
struct btrfs_scrub_progress *progress)
{
struct btrfs_device *dev;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
struct scrub_ctx *sctx = NULL;
mutex_lock(&fs_info->fs_devices->device_list_mutex);
dev = btrfs_find_device(fs_info->fs_devices, devid, NULL, NULL);
if (dev)
sctx = dev->scrub_ctx;
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
if (sctx)
memcpy(progress, &sctx->stat, sizeof(*progress));
mutex_unlock(&fs_info->fs_devices->device_list_mutex);
Btrfs: rename the scrub context structure The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit is a first preparation step to adapt the scrub code to be shareable for the device replace procedure. The block device will be removed from the scrub context state structure in a later step. It used to be the source block device. The scrub code as it is used for the device replace procedure reads the source data from whereever it is optimal. The source device might even be gone (disconnected, for instance due to a hardware failure). Or the drive can be so faulty so that the device replace procedure tries to avoid access to the faulty source drive as much as possible, and only if all other mirrors are damaged, as a last resort, the source disk is accessed. The modified scrub code operates as if it would handle the source drive and thereby generates an exact copy of the source disk on the target disk, even if the source disk is not present at all. Therefore the block device pointer to the source disk is removed in a later patch, and therefore the context structure is renamed (this is the goal of the current patch) to reflect that no source block device scope is there anymore. Summary: This first preparation step consists of a textual substitution of the term "dev" to the term "ctx" whereever the scrub context is used. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-11-02 16:58:09 +08:00
return dev ? (sctx ? 0 : -ENOTCONN) : -ENODEV;
}
static void scrub_remap_extent(struct btrfs_fs_info *fs_info,
u64 extent_logical, u32 extent_len,
u64 *extent_physical,
struct btrfs_device **extent_dev,
int *extent_mirror_num)
{
u64 mapped_length;
struct btrfs_bio *bbio = NULL;
int ret;
mapped_length = extent_len;
ret = btrfs_map_block(fs_info, BTRFS_MAP_READ, extent_logical,
&mapped_length, &bbio, 0);
if (ret || !bbio || mapped_length < extent_len ||
!bbio->stripes[0].dev->bdev) {
btrfs_put_bbio(bbio);
return;
}
*extent_physical = bbio->stripes[0].physical;
*extent_mirror_num = bbio->mirror_num;
*extent_dev = bbio->stripes[0].dev;
btrfs_put_bbio(bbio);
}