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linux/drivers/md/dm.c
Christoph Hellwig 1a581b7216 dm: track per-add_disk holder relations in DM 
dm is a bit special in that it opens the underlying devices.  Commit
89f871af1b ("dm: delay registering the gendisk") tried to accommodate
that by allowing to add the holder to the list before add_gendisk and
then just add them to sysfs once add_disk is called.  But that leads to
really odd lifetime problems and error handling problems as we can't
know the state of the kobjects and don't unwind properly.  To fix this
switch to just registering all existing table_devices with the holder
code right after add_disk, and remove them before calling del_gendisk.

Fixes: 89f871af1b ("dm: delay registering the gendisk")
Reported-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Mike Snitzer <snitzer@kernel.org>
Link: https://lore.kernel.org/r/20221115141054.1051801-7-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-16 15:19:56 -07:00

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/*
* Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
* Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
*
* This file is released under the GPL.
*/
#include "dm-core.h"
#include "dm-rq.h"
#include "dm-uevent.h"
#include "dm-ima.h"
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/sched/mm.h>
#include <linux/sched/signal.h>
#include <linux/blkpg.h>
#include <linux/bio.h>
#include <linux/mempool.h>
#include <linux/dax.h>
#include <linux/slab.h>
#include <linux/idr.h>
#include <linux/uio.h>
#include <linux/hdreg.h>
#include <linux/delay.h>
#include <linux/wait.h>
#include <linux/pr.h>
#include <linux/refcount.h>
#include <linux/part_stat.h>
#include <linux/blk-crypto.h>
#include <linux/blk-crypto-profile.h>
#define DM_MSG_PREFIX "core"
/*
* Cookies are numeric values sent with CHANGE and REMOVE
* uevents while resuming, removing or renaming the device.
*/
#define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE"
#define DM_COOKIE_LENGTH 24
/*
* For REQ_POLLED fs bio, this flag is set if we link mapped underlying
* dm_io into one list, and reuse bio->bi_private as the list head. Before
* ending this fs bio, we will recover its ->bi_private.
*/
#define REQ_DM_POLL_LIST REQ_DRV
static const char *_name = DM_NAME;
static unsigned int major = 0;
static unsigned int _major = 0;
static DEFINE_IDR(_minor_idr);
static DEFINE_SPINLOCK(_minor_lock);
static void do_deferred_remove(struct work_struct *w);
static DECLARE_WORK(deferred_remove_work, do_deferred_remove);
static struct workqueue_struct *deferred_remove_workqueue;
atomic_t dm_global_event_nr = ATOMIC_INIT(0);
DECLARE_WAIT_QUEUE_HEAD(dm_global_eventq);
void dm_issue_global_event(void)
{
atomic_inc(&dm_global_event_nr);
wake_up(&dm_global_eventq);
}
DEFINE_STATIC_KEY_FALSE(stats_enabled);
DEFINE_STATIC_KEY_FALSE(swap_bios_enabled);
DEFINE_STATIC_KEY_FALSE(zoned_enabled);
/*
* One of these is allocated (on-stack) per original bio.
*/
struct clone_info {
struct dm_table *map;
struct bio *bio;
struct dm_io *io;
sector_t sector;
unsigned sector_count;
bool is_abnormal_io:1;
bool submit_as_polled:1;
};
static inline struct dm_target_io *clone_to_tio(struct bio *clone)
{
return container_of(clone, struct dm_target_io, clone);
}
void *dm_per_bio_data(struct bio *bio, size_t data_size)
{
if (!dm_tio_flagged(clone_to_tio(bio), DM_TIO_INSIDE_DM_IO))
return (char *)bio - DM_TARGET_IO_BIO_OFFSET - data_size;
return (char *)bio - DM_IO_BIO_OFFSET - data_size;
}
EXPORT_SYMBOL_GPL(dm_per_bio_data);
struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size)
{
struct dm_io *io = (struct dm_io *)((char *)data + data_size);
if (io->magic == DM_IO_MAGIC)
return (struct bio *)((char *)io + DM_IO_BIO_OFFSET);
BUG_ON(io->magic != DM_TIO_MAGIC);
return (struct bio *)((char *)io + DM_TARGET_IO_BIO_OFFSET);
}
EXPORT_SYMBOL_GPL(dm_bio_from_per_bio_data);
unsigned dm_bio_get_target_bio_nr(const struct bio *bio)
{
return container_of(bio, struct dm_target_io, clone)->target_bio_nr;
}
EXPORT_SYMBOL_GPL(dm_bio_get_target_bio_nr);
#define MINOR_ALLOCED ((void *)-1)
#define DM_NUMA_NODE NUMA_NO_NODE
static int dm_numa_node = DM_NUMA_NODE;
#define DEFAULT_SWAP_BIOS (8 * 1048576 / PAGE_SIZE)
static int swap_bios = DEFAULT_SWAP_BIOS;
static int get_swap_bios(void)
{
int latch = READ_ONCE(swap_bios);
if (unlikely(latch <= 0))
latch = DEFAULT_SWAP_BIOS;
return latch;
}
struct table_device {
struct list_head list;
refcount_t count;
struct dm_dev dm_dev;
};
/*
* Bio-based DM's mempools' reserved IOs set by the user.
*/
#define RESERVED_BIO_BASED_IOS 16
static unsigned reserved_bio_based_ios = RESERVED_BIO_BASED_IOS;
static int __dm_get_module_param_int(int *module_param, int min, int max)
{
int param = READ_ONCE(*module_param);
int modified_param = 0;
bool modified = true;
if (param < min)
modified_param = min;
else if (param > max)
modified_param = max;
else
modified = false;
if (modified) {
(void)cmpxchg(module_param, param, modified_param);
param = modified_param;
}
return param;
}
unsigned __dm_get_module_param(unsigned *module_param,
unsigned def, unsigned max)
{
unsigned param = READ_ONCE(*module_param);
unsigned modified_param = 0;
if (!param)
modified_param = def;
else if (param > max)
modified_param = max;
if (modified_param) {
(void)cmpxchg(module_param, param, modified_param);
param = modified_param;
}
return param;
}
unsigned dm_get_reserved_bio_based_ios(void)
{
return __dm_get_module_param(&reserved_bio_based_ios,
RESERVED_BIO_BASED_IOS, DM_RESERVED_MAX_IOS);
}
EXPORT_SYMBOL_GPL(dm_get_reserved_bio_based_ios);
static unsigned dm_get_numa_node(void)
{
return __dm_get_module_param_int(&dm_numa_node,
DM_NUMA_NODE, num_online_nodes() - 1);
}
static int __init local_init(void)
{
int r;
r = dm_uevent_init();
if (r)
return r;
deferred_remove_workqueue = alloc_workqueue("kdmremove", WQ_UNBOUND, 1);
if (!deferred_remove_workqueue) {
r = -ENOMEM;
goto out_uevent_exit;
}
_major = major;
r = register_blkdev(_major, _name);
if (r < 0)
goto out_free_workqueue;
if (!_major)
_major = r;
return 0;
out_free_workqueue:
destroy_workqueue(deferred_remove_workqueue);
out_uevent_exit:
dm_uevent_exit();
return r;
}
static void local_exit(void)
{
flush_scheduled_work();
destroy_workqueue(deferred_remove_workqueue);
unregister_blkdev(_major, _name);
dm_uevent_exit();
_major = 0;
DMINFO("cleaned up");
}
static int (*_inits[])(void) __initdata = {
local_init,
dm_target_init,
dm_linear_init,
dm_stripe_init,
dm_io_init,
dm_kcopyd_init,
dm_interface_init,
dm_statistics_init,
};
static void (*_exits[])(void) = {
local_exit,
dm_target_exit,
dm_linear_exit,
dm_stripe_exit,
dm_io_exit,
dm_kcopyd_exit,
dm_interface_exit,
dm_statistics_exit,
};
static int __init dm_init(void)
{
const int count = ARRAY_SIZE(_inits);
int r, i;
#if (IS_ENABLED(CONFIG_IMA) && !IS_ENABLED(CONFIG_IMA_DISABLE_HTABLE))
DMWARN("CONFIG_IMA_DISABLE_HTABLE is disabled."
" Duplicate IMA measurements will not be recorded in the IMA log.");
#endif
for (i = 0; i < count; i++) {
r = _inits[i]();
if (r)
goto bad;
}
return 0;
bad:
while (i--)
_exits[i]();
return r;
}
static void __exit dm_exit(void)
{
int i = ARRAY_SIZE(_exits);
while (i--)
_exits[i]();
/*
* Should be empty by this point.
*/
idr_destroy(&_minor_idr);
}
/*
* Block device functions
*/
int dm_deleting_md(struct mapped_device *md)
{
return test_bit(DMF_DELETING, &md->flags);
}
static int dm_blk_open(struct block_device *bdev, fmode_t mode)
{
struct mapped_device *md;
spin_lock(&_minor_lock);
md = bdev->bd_disk->private_data;
if (!md)
goto out;
if (test_bit(DMF_FREEING, &md->flags) ||
dm_deleting_md(md)) {
md = NULL;
goto out;
}
dm_get(md);
atomic_inc(&md->open_count);
out:
spin_unlock(&_minor_lock);
return md ? 0 : -ENXIO;
}
static void dm_blk_close(struct gendisk *disk, fmode_t mode)
{
struct mapped_device *md;
spin_lock(&_minor_lock);
md = disk->private_data;
if (WARN_ON(!md))
goto out;
if (atomic_dec_and_test(&md->open_count) &&
(test_bit(DMF_DEFERRED_REMOVE, &md->flags)))
queue_work(deferred_remove_workqueue, &deferred_remove_work);
dm_put(md);
out:
spin_unlock(&_minor_lock);
}
int dm_open_count(struct mapped_device *md)
{
return atomic_read(&md->open_count);
}
/*
* Guarantees nothing is using the device before it's deleted.
*/
int dm_lock_for_deletion(struct mapped_device *md, bool mark_deferred, bool only_deferred)
{
int r = 0;
spin_lock(&_minor_lock);
if (dm_open_count(md)) {
r = -EBUSY;
if (mark_deferred)
set_bit(DMF_DEFERRED_REMOVE, &md->flags);
} else if (only_deferred && !test_bit(DMF_DEFERRED_REMOVE, &md->flags))
r = -EEXIST;
else
set_bit(DMF_DELETING, &md->flags);
spin_unlock(&_minor_lock);
return r;
}
int dm_cancel_deferred_remove(struct mapped_device *md)
{
int r = 0;
spin_lock(&_minor_lock);
if (test_bit(DMF_DELETING, &md->flags))
r = -EBUSY;
else
clear_bit(DMF_DEFERRED_REMOVE, &md->flags);
spin_unlock(&_minor_lock);
return r;
}
static void do_deferred_remove(struct work_struct *w)
{
dm_deferred_remove();
}
static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
struct mapped_device *md = bdev->bd_disk->private_data;
return dm_get_geometry(md, geo);
}
static int dm_prepare_ioctl(struct mapped_device *md, int *srcu_idx,
struct block_device **bdev)
{
struct dm_target *ti;
struct dm_table *map;
int r;
retry:
r = -ENOTTY;
map = dm_get_live_table(md, srcu_idx);
if (!map || !dm_table_get_size(map))
return r;
/* We only support devices that have a single target */
if (map->num_targets != 1)
return r;
ti = dm_table_get_target(map, 0);
if (!ti->type->prepare_ioctl)
return r;
if (dm_suspended_md(md))
return -EAGAIN;
r = ti->type->prepare_ioctl(ti, bdev);
if (r == -ENOTCONN && !fatal_signal_pending(current)) {
dm_put_live_table(md, *srcu_idx);
msleep(10);
goto retry;
}
return r;
}
static void dm_unprepare_ioctl(struct mapped_device *md, int srcu_idx)
{
dm_put_live_table(md, srcu_idx);
}
static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
unsigned int cmd, unsigned long arg)
{
struct mapped_device *md = bdev->bd_disk->private_data;
int r, srcu_idx;
r = dm_prepare_ioctl(md, &srcu_idx, &bdev);
if (r < 0)
goto out;
if (r > 0) {
/*
* Target determined this ioctl is being issued against a
* subset of the parent bdev; require extra privileges.
*/
if (!capable(CAP_SYS_RAWIO)) {
DMDEBUG_LIMIT(
"%s: sending ioctl %x to DM device without required privilege.",
current->comm, cmd);
r = -ENOIOCTLCMD;
goto out;
}
}
if (!bdev->bd_disk->fops->ioctl)
r = -ENOTTY;
else
r = bdev->bd_disk->fops->ioctl(bdev, mode, cmd, arg);
out:
dm_unprepare_ioctl(md, srcu_idx);
return r;
}
u64 dm_start_time_ns_from_clone(struct bio *bio)
{
return jiffies_to_nsecs(clone_to_tio(bio)->io->start_time);
}
EXPORT_SYMBOL_GPL(dm_start_time_ns_from_clone);
static bool bio_is_flush_with_data(struct bio *bio)
{
return ((bio->bi_opf & REQ_PREFLUSH) && bio->bi_iter.bi_size);
}
static void dm_io_acct(struct dm_io *io, bool end)
{
struct dm_stats_aux *stats_aux = &io->stats_aux;
unsigned long start_time = io->start_time;
struct mapped_device *md = io->md;
struct bio *bio = io->orig_bio;
unsigned int sectors;
/*
* If REQ_PREFLUSH set, don't account payload, it will be
* submitted (and accounted) after this flush completes.
*/
if (bio_is_flush_with_data(bio))
sectors = 0;
else if (likely(!(dm_io_flagged(io, DM_IO_WAS_SPLIT))))
sectors = bio_sectors(bio);
else
sectors = io->sectors;
if (!end)
bdev_start_io_acct(bio->bi_bdev, sectors, bio_op(bio),
start_time);
else
bdev_end_io_acct(bio->bi_bdev, bio_op(bio), start_time);
if (static_branch_unlikely(&stats_enabled) &&
unlikely(dm_stats_used(&md->stats))) {
sector_t sector;
if (likely(!dm_io_flagged(io, DM_IO_WAS_SPLIT)))
sector = bio->bi_iter.bi_sector;
else
sector = bio_end_sector(bio) - io->sector_offset;
dm_stats_account_io(&md->stats, bio_data_dir(bio),
sector, sectors,
end, start_time, stats_aux);
}
}
static void __dm_start_io_acct(struct dm_io *io)
{
dm_io_acct(io, false);
}
static void dm_start_io_acct(struct dm_io *io, struct bio *clone)
{
/*
* Ensure IO accounting is only ever started once.
*/
if (dm_io_flagged(io, DM_IO_ACCOUNTED))
return;
/* Expect no possibility for race unless DM_TIO_IS_DUPLICATE_BIO. */
if (!clone || likely(dm_tio_is_normal(clone_to_tio(clone)))) {
dm_io_set_flag(io, DM_IO_ACCOUNTED);
} else {
unsigned long flags;
/* Can afford locking given DM_TIO_IS_DUPLICATE_BIO */
spin_lock_irqsave(&io->lock, flags);
if (dm_io_flagged(io, DM_IO_ACCOUNTED)) {
spin_unlock_irqrestore(&io->lock, flags);
return;
}
dm_io_set_flag(io, DM_IO_ACCOUNTED);
spin_unlock_irqrestore(&io->lock, flags);
}
__dm_start_io_acct(io);
}
static void dm_end_io_acct(struct dm_io *io)
{
dm_io_acct(io, true);
}
static struct dm_io *alloc_io(struct mapped_device *md, struct bio *bio)
{
struct dm_io *io;
struct dm_target_io *tio;
struct bio *clone;
clone = bio_alloc_clone(NULL, bio, GFP_NOIO, &md->mempools->io_bs);
tio = clone_to_tio(clone);
tio->flags = 0;
dm_tio_set_flag(tio, DM_TIO_INSIDE_DM_IO);
tio->io = NULL;
io = container_of(tio, struct dm_io, tio);
io->magic = DM_IO_MAGIC;
io->status = BLK_STS_OK;
/* one ref is for submission, the other is for completion */
atomic_set(&io->io_count, 2);
this_cpu_inc(*md->pending_io);
io->orig_bio = bio;
io->md = md;
spin_lock_init(&io->lock);
io->start_time = jiffies;
io->flags = 0;
if (static_branch_unlikely(&stats_enabled))
dm_stats_record_start(&md->stats, &io->stats_aux);
return io;
}
static void free_io(struct dm_io *io)
{
bio_put(&io->tio.clone);
}
static struct bio *alloc_tio(struct clone_info *ci, struct dm_target *ti,
unsigned target_bio_nr, unsigned *len, gfp_t gfp_mask)
{
struct mapped_device *md = ci->io->md;
struct dm_target_io *tio;
struct bio *clone;
if (!ci->io->tio.io) {
/* the dm_target_io embedded in ci->io is available */
tio = &ci->io->tio;
/* alloc_io() already initialized embedded clone */
clone = &tio->clone;
} else {
clone = bio_alloc_clone(NULL, ci->bio, gfp_mask,
&md->mempools->bs);
if (!clone)
return NULL;
/* REQ_DM_POLL_LIST shouldn't be inherited */
clone->bi_opf &= ~REQ_DM_POLL_LIST;
tio = clone_to_tio(clone);
tio->flags = 0; /* also clears DM_TIO_INSIDE_DM_IO */
}
tio->magic = DM_TIO_MAGIC;
tio->io = ci->io;
tio->ti = ti;
tio->target_bio_nr = target_bio_nr;
tio->len_ptr = len;
tio->old_sector = 0;
/* Set default bdev, but target must bio_set_dev() before issuing IO */
clone->bi_bdev = md->disk->part0;
if (unlikely(ti->needs_bio_set_dev))
bio_set_dev(clone, md->disk->part0);
if (len) {
clone->bi_iter.bi_size = to_bytes(*len);
if (bio_integrity(clone))
bio_integrity_trim(clone);
}
return clone;
}
static void free_tio(struct bio *clone)
{
if (dm_tio_flagged(clone_to_tio(clone), DM_TIO_INSIDE_DM_IO))
return;
bio_put(clone);
}
/*
* Add the bio to the list of deferred io.
*/
static void queue_io(struct mapped_device *md, struct bio *bio)
{
unsigned long flags;
spin_lock_irqsave(&md->deferred_lock, flags);
bio_list_add(&md->deferred, bio);
spin_unlock_irqrestore(&md->deferred_lock, flags);
queue_work(md->wq, &md->work);
}
/*
* Everyone (including functions in this file), should use this
* function to access the md->map field, and make sure they call
* dm_put_live_table() when finished.
*/
struct dm_table *dm_get_live_table(struct mapped_device *md,
int *srcu_idx) __acquires(md->io_barrier)
{
*srcu_idx = srcu_read_lock(&md->io_barrier);
return srcu_dereference(md->map, &md->io_barrier);
}
void dm_put_live_table(struct mapped_device *md,
int srcu_idx) __releases(md->io_barrier)
{
srcu_read_unlock(&md->io_barrier, srcu_idx);
}
void dm_sync_table(struct mapped_device *md)
{
synchronize_srcu(&md->io_barrier);
synchronize_rcu_expedited();
}
/*
* A fast alternative to dm_get_live_table/dm_put_live_table.
* The caller must not block between these two functions.
*/
static struct dm_table *dm_get_live_table_fast(struct mapped_device *md) __acquires(RCU)
{
rcu_read_lock();
return rcu_dereference(md->map);
}
static void dm_put_live_table_fast(struct mapped_device *md) __releases(RCU)
{
rcu_read_unlock();
}
static inline struct dm_table *dm_get_live_table_bio(struct mapped_device *md,
int *srcu_idx, blk_opf_t bio_opf)
{
if (bio_opf & REQ_NOWAIT)
return dm_get_live_table_fast(md);
else
return dm_get_live_table(md, srcu_idx);
}
static inline void dm_put_live_table_bio(struct mapped_device *md, int srcu_idx,
blk_opf_t bio_opf)
{
if (bio_opf & REQ_NOWAIT)
dm_put_live_table_fast(md);
else
dm_put_live_table(md, srcu_idx);
}
static char *_dm_claim_ptr = "I belong to device-mapper";
/*
* Open a table device so we can use it as a map destination.
*/
static struct table_device *open_table_device(struct mapped_device *md,
dev_t dev, fmode_t mode)
{
struct table_device *td;
struct block_device *bdev;
u64 part_off;
int r;
td = kmalloc_node(sizeof(*td), GFP_KERNEL, md->numa_node_id);
if (!td)
return ERR_PTR(-ENOMEM);
refcount_set(&td->count, 1);
bdev = blkdev_get_by_dev(dev, mode | FMODE_EXCL, _dm_claim_ptr);
if (IS_ERR(bdev)) {
r = PTR_ERR(bdev);
goto out_free_td;
}
/*
* We can be called before the dm disk is added. In that case we can't
* register the holder relation here. It will be done once add_disk was
* called.
*/
if (md->disk->slave_dir) {
r = bd_link_disk_holder(bdev, md->disk);
if (r)
goto out_blkdev_put;
}
td->dm_dev.mode = mode;
td->dm_dev.bdev = bdev;
td->dm_dev.dax_dev = fs_dax_get_by_bdev(bdev, &part_off, NULL, NULL);
format_dev_t(td->dm_dev.name, dev);
list_add(&td->list, &md->table_devices);
return td;
out_blkdev_put:
blkdev_put(bdev, mode | FMODE_EXCL);
out_free_td:
kfree(td);
return ERR_PTR(r);
}
/*
* Close a table device that we've been using.
*/
static void close_table_device(struct table_device *td, struct mapped_device *md)
{
if (md->disk->slave_dir)
bd_unlink_disk_holder(td->dm_dev.bdev, md->disk);
blkdev_put(td->dm_dev.bdev, td->dm_dev.mode | FMODE_EXCL);
put_dax(td->dm_dev.dax_dev);
list_del(&td->list);
kfree(td);
}
static struct table_device *find_table_device(struct list_head *l, dev_t dev,
fmode_t mode)
{
struct table_device *td;
list_for_each_entry(td, l, list)
if (td->dm_dev.bdev->bd_dev == dev && td->dm_dev.mode == mode)
return td;
return NULL;
}
int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode,
struct dm_dev **result)
{
struct table_device *td;
mutex_lock(&md->table_devices_lock);
td = find_table_device(&md->table_devices, dev, mode);
if (!td) {
td = open_table_device(md, dev, mode);
if (IS_ERR(td)) {
mutex_unlock(&md->table_devices_lock);
return PTR_ERR(td);
}
} else {
refcount_inc(&td->count);
}
mutex_unlock(&md->table_devices_lock);
*result = &td->dm_dev;
return 0;
}
void dm_put_table_device(struct mapped_device *md, struct dm_dev *d)
{
struct table_device *td = container_of(d, struct table_device, dm_dev);
mutex_lock(&md->table_devices_lock);
if (refcount_dec_and_test(&td->count))
close_table_device(td, md);
mutex_unlock(&md->table_devices_lock);
}
/*
* Get the geometry associated with a dm device
*/
int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo)
{
*geo = md->geometry;
return 0;
}
/*
* Set the geometry of a device.
*/
int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo)
{
sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors;
if (geo->start > sz) {
DMERR("Start sector is beyond the geometry limits.");
return -EINVAL;
}
md->geometry = *geo;
return 0;
}
static int __noflush_suspending(struct mapped_device *md)
{
return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
}
static void dm_requeue_add_io(struct dm_io *io, bool first_stage)
{
struct mapped_device *md = io->md;
if (first_stage) {
struct dm_io *next = md->requeue_list;
md->requeue_list = io;
io->next = next;
} else {
bio_list_add_head(&md->deferred, io->orig_bio);
}
}
static void dm_kick_requeue(struct mapped_device *md, bool first_stage)
{
if (first_stage)
queue_work(md->wq, &md->requeue_work);
else
queue_work(md->wq, &md->work);
}
/*
* Return true if the dm_io's original bio is requeued.
* io->status is updated with error if requeue disallowed.
*/
static bool dm_handle_requeue(struct dm_io *io, bool first_stage)
{
struct bio *bio = io->orig_bio;
bool handle_requeue = (io->status == BLK_STS_DM_REQUEUE);
bool handle_polled_eagain = ((io->status == BLK_STS_AGAIN) &&
(bio->bi_opf & REQ_POLLED));
struct mapped_device *md = io->md;
bool requeued = false;
if (handle_requeue || handle_polled_eagain) {
unsigned long flags;
if (bio->bi_opf & REQ_POLLED) {
/*
* Upper layer won't help us poll split bio
* (io->orig_bio may only reflect a subset of the
* pre-split original) so clear REQ_POLLED.
*/
bio_clear_polled(bio);
}
/*
* Target requested pushing back the I/O or
* polled IO hit BLK_STS_AGAIN.
*/
spin_lock_irqsave(&md->deferred_lock, flags);
if ((__noflush_suspending(md) &&
!WARN_ON_ONCE(dm_is_zone_write(md, bio))) ||
handle_polled_eagain || first_stage) {
dm_requeue_add_io(io, first_stage);
requeued = true;
} else {
/*
* noflush suspend was interrupted or this is
* a write to a zoned target.
*/
io->status = BLK_STS_IOERR;
}
spin_unlock_irqrestore(&md->deferred_lock, flags);
}
if (requeued)
dm_kick_requeue(md, first_stage);
return requeued;
}
static void __dm_io_complete(struct dm_io *io, bool first_stage)
{
struct bio *bio = io->orig_bio;
struct mapped_device *md = io->md;
blk_status_t io_error;
bool requeued;
requeued = dm_handle_requeue(io, first_stage);
if (requeued && first_stage)
return;
io_error = io->status;
if (dm_io_flagged(io, DM_IO_ACCOUNTED))
dm_end_io_acct(io);
else if (!io_error) {
/*
* Must handle target that DM_MAPIO_SUBMITTED only to
* then bio_endio() rather than dm_submit_bio_remap()
*/
__dm_start_io_acct(io);
dm_end_io_acct(io);
}
free_io(io);
smp_wmb();
this_cpu_dec(*md->pending_io);
/* nudge anyone waiting on suspend queue */
if (unlikely(wq_has_sleeper(&md->wait)))
wake_up(&md->wait);
/* Return early if the original bio was requeued */
if (requeued)
return;
if (bio_is_flush_with_data(bio)) {
/*
* Preflush done for flush with data, reissue
* without REQ_PREFLUSH.
*/
bio->bi_opf &= ~REQ_PREFLUSH;
queue_io(md, bio);
} else {
/* done with normal IO or empty flush */
if (io_error)
bio->bi_status = io_error;
bio_endio(bio);
}
}
static void dm_wq_requeue_work(struct work_struct *work)
{
struct mapped_device *md = container_of(work, struct mapped_device,
requeue_work);
unsigned long flags;
struct dm_io *io;
/* reuse deferred lock to simplify dm_handle_requeue */
spin_lock_irqsave(&md->deferred_lock, flags);
io = md->requeue_list;
md->requeue_list = NULL;
spin_unlock_irqrestore(&md->deferred_lock, flags);
while (io) {
struct dm_io *next = io->next;
dm_io_rewind(io, &md->disk->bio_split);
io->next = NULL;
__dm_io_complete(io, false);
io = next;
}
}
/*
* Two staged requeue:
*
* 1) io->orig_bio points to the real original bio, and the part mapped to
* this io must be requeued, instead of other parts of the original bio.
*
* 2) io->orig_bio points to new cloned bio which matches the requeued dm_io.
*/
static void dm_io_complete(struct dm_io *io)
{
bool first_requeue;
/*
* Only dm_io that has been split needs two stage requeue, otherwise
* we may run into long bio clone chain during suspend and OOM could
* be triggered.
*
* Also flush data dm_io won't be marked as DM_IO_WAS_SPLIT, so they
* also aren't handled via the first stage requeue.
*/
if (dm_io_flagged(io, DM_IO_WAS_SPLIT))
first_requeue = true;
else
first_requeue = false;
__dm_io_complete(io, first_requeue);
}
/*
* Decrements the number of outstanding ios that a bio has been
* cloned into, completing the original io if necc.
*/
static inline void __dm_io_dec_pending(struct dm_io *io)
{
if (atomic_dec_and_test(&io->io_count))
dm_io_complete(io);
}
static void dm_io_set_error(struct dm_io *io, blk_status_t error)
{
unsigned long flags;
/* Push-back supersedes any I/O errors */
spin_lock_irqsave(&io->lock, flags);
if (!(io->status == BLK_STS_DM_REQUEUE &&
__noflush_suspending(io->md))) {
io->status = error;
}
spin_unlock_irqrestore(&io->lock, flags);
}
static void dm_io_dec_pending(struct dm_io *io, blk_status_t error)
{
if (unlikely(error))
dm_io_set_error(io, error);
__dm_io_dec_pending(io);
}
void disable_discard(struct mapped_device *md)
{
struct queue_limits *limits = dm_get_queue_limits(md);
/* device doesn't really support DISCARD, disable it */
limits->max_discard_sectors = 0;
}
void disable_write_zeroes(struct mapped_device *md)
{
struct queue_limits *limits = dm_get_queue_limits(md);
/* device doesn't really support WRITE ZEROES, disable it */
limits->max_write_zeroes_sectors = 0;
}
static bool swap_bios_limit(struct dm_target *ti, struct bio *bio)
{
return unlikely((bio->bi_opf & REQ_SWAP) != 0) && unlikely(ti->limit_swap_bios);
}
static void clone_endio(struct bio *bio)
{
blk_status_t error = bio->bi_status;
struct dm_target_io *tio = clone_to_tio(bio);
struct dm_target *ti = tio->ti;
dm_endio_fn endio = ti->type->end_io;
struct dm_io *io = tio->io;
struct mapped_device *md = io->md;
if (unlikely(error == BLK_STS_TARGET)) {
if (bio_op(bio) == REQ_OP_DISCARD &&
!bdev_max_discard_sectors(bio->bi_bdev))
disable_discard(md);
else if (bio_op(bio) == REQ_OP_WRITE_ZEROES &&
!bdev_write_zeroes_sectors(bio->bi_bdev))
disable_write_zeroes(md);
}
if (static_branch_unlikely(&zoned_enabled) &&
unlikely(bdev_is_zoned(bio->bi_bdev)))
dm_zone_endio(io, bio);
if (endio) {
int r = endio(ti, bio, &error);
switch (r) {
case DM_ENDIO_REQUEUE:
if (static_branch_unlikely(&zoned_enabled)) {
/*
* Requeuing writes to a sequential zone of a zoned
* target will break the sequential write pattern:
* fail such IO.
*/
if (WARN_ON_ONCE(dm_is_zone_write(md, bio)))
error = BLK_STS_IOERR;
else
error = BLK_STS_DM_REQUEUE;
} else
error = BLK_STS_DM_REQUEUE;
fallthrough;
case DM_ENDIO_DONE:
break;
case DM_ENDIO_INCOMPLETE:
/* The target will handle the io */
return;
default:
DMCRIT("unimplemented target endio return value: %d", r);
BUG();
}
}
if (static_branch_unlikely(&swap_bios_enabled) &&
unlikely(swap_bios_limit(ti, bio)))
up(&md->swap_bios_semaphore);
free_tio(bio);
dm_io_dec_pending(io, error);
}
/*
* Return maximum size of I/O possible at the supplied sector up to the current
* target boundary.
*/
static inline sector_t max_io_len_target_boundary(struct dm_target *ti,
sector_t target_offset)
{
return ti->len - target_offset;
}
static sector_t max_io_len(struct dm_target *ti, sector_t sector)
{
sector_t target_offset = dm_target_offset(ti, sector);
sector_t len = max_io_len_target_boundary(ti, target_offset);
/*
* Does the target need to split IO even further?
* - varied (per target) IO splitting is a tenet of DM; this
* explains why stacked chunk_sectors based splitting via
* bio_split_to_limits() isn't possible here.
*/
if (!ti->max_io_len)
return len;
return min_t(sector_t, len,
min(queue_max_sectors(ti->table->md->queue),
blk_chunk_sectors_left(target_offset, ti->max_io_len)));
}
int dm_set_target_max_io_len(struct dm_target *ti, sector_t len)
{
if (len > UINT_MAX) {
DMERR("Specified maximum size of target IO (%llu) exceeds limit (%u)",
(unsigned long long)len, UINT_MAX);
ti->error = "Maximum size of target IO is too large";
return -EINVAL;
}
ti->max_io_len = (uint32_t) len;
return 0;
}
EXPORT_SYMBOL_GPL(dm_set_target_max_io_len);
static struct dm_target *dm_dax_get_live_target(struct mapped_device *md,
sector_t sector, int *srcu_idx)
__acquires(md->io_barrier)
{
struct dm_table *map;
struct dm_target *ti;
map = dm_get_live_table(md, srcu_idx);
if (!map)
return NULL;
ti = dm_table_find_target(map, sector);
if (!ti)
return NULL;
return ti;
}
static long dm_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff,
long nr_pages, enum dax_access_mode mode, void **kaddr,
pfn_t *pfn)
{
struct mapped_device *md = dax_get_private(dax_dev);
sector_t sector = pgoff * PAGE_SECTORS;
struct dm_target *ti;
long len, ret = -EIO;
int srcu_idx;
ti = dm_dax_get_live_target(md, sector, &srcu_idx);
if (!ti)
goto out;
if (!ti->type->direct_access)
goto out;
len = max_io_len(ti, sector) / PAGE_SECTORS;
if (len < 1)
goto out;
nr_pages = min(len, nr_pages);
ret = ti->type->direct_access(ti, pgoff, nr_pages, mode, kaddr, pfn);
out:
dm_put_live_table(md, srcu_idx);
return ret;
}
static int dm_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
size_t nr_pages)
{
struct mapped_device *md = dax_get_private(dax_dev);
sector_t sector = pgoff * PAGE_SECTORS;
struct dm_target *ti;
int ret = -EIO;
int srcu_idx;
ti = dm_dax_get_live_target(md, sector, &srcu_idx);
if (!ti)
goto out;
if (WARN_ON(!ti->type->dax_zero_page_range)) {
/*
* ->zero_page_range() is mandatory dax operation. If we are
* here, something is wrong.
*/
goto out;
}
ret = ti->type->dax_zero_page_range(ti, pgoff, nr_pages);
out:
dm_put_live_table(md, srcu_idx);
return ret;
}
static size_t dm_dax_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff,
void *addr, size_t bytes, struct iov_iter *i)
{
struct mapped_device *md = dax_get_private(dax_dev);
sector_t sector = pgoff * PAGE_SECTORS;
struct dm_target *ti;
int srcu_idx;
long ret = 0;
ti = dm_dax_get_live_target(md, sector, &srcu_idx);
if (!ti || !ti->type->dax_recovery_write)
goto out;
ret = ti->type->dax_recovery_write(ti, pgoff, addr, bytes, i);
out:
dm_put_live_table(md, srcu_idx);
return ret;
}
/*
* A target may call dm_accept_partial_bio only from the map routine. It is
* allowed for all bio types except REQ_PREFLUSH, REQ_OP_ZONE_* zone management
* operations, REQ_OP_ZONE_APPEND (zone append writes) and any bio serviced by
* __send_duplicate_bios().
*
* dm_accept_partial_bio informs the dm that the target only wants to process
* additional n_sectors sectors of the bio and the rest of the data should be
* sent in a next bio.
*
* A diagram that explains the arithmetics:
* +--------------------+---------------+-------+
* | 1 | 2 | 3 |
* +--------------------+---------------+-------+
*
* <-------------- *tio->len_ptr --------------->
* <----- bio_sectors ----->
* <-- n_sectors -->
*
* Region 1 was already iterated over with bio_advance or similar function.
* (it may be empty if the target doesn't use bio_advance)
* Region 2 is the remaining bio size that the target wants to process.
* (it may be empty if region 1 is non-empty, although there is no reason
* to make it empty)
* The target requires that region 3 is to be sent in the next bio.
*
* If the target wants to receive multiple copies of the bio (via num_*bios, etc),
* the partially processed part (the sum of regions 1+2) must be the same for all
* copies of the bio.
*/
void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors)
{
struct dm_target_io *tio = clone_to_tio(bio);
struct dm_io *io = tio->io;
unsigned bio_sectors = bio_sectors(bio);
BUG_ON(dm_tio_flagged(tio, DM_TIO_IS_DUPLICATE_BIO));
BUG_ON(op_is_zone_mgmt(bio_op(bio)));
BUG_ON(bio_op(bio) == REQ_OP_ZONE_APPEND);
BUG_ON(bio_sectors > *tio->len_ptr);
BUG_ON(n_sectors > bio_sectors);
*tio->len_ptr -= bio_sectors - n_sectors;
bio->bi_iter.bi_size = n_sectors << SECTOR_SHIFT;
/*
* __split_and_process_bio() may have already saved mapped part
* for accounting but it is being reduced so update accordingly.
*/
dm_io_set_flag(io, DM_IO_WAS_SPLIT);
io->sectors = n_sectors;
io->sector_offset = bio_sectors(io->orig_bio);
}
EXPORT_SYMBOL_GPL(dm_accept_partial_bio);
/*
* @clone: clone bio that DM core passed to target's .map function
* @tgt_clone: clone of @clone bio that target needs submitted
*
* Targets should use this interface to submit bios they take
* ownership of when returning DM_MAPIO_SUBMITTED.
*
* Target should also enable ti->accounts_remapped_io
*/
void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone)
{
struct dm_target_io *tio = clone_to_tio(clone);
struct dm_io *io = tio->io;
/* establish bio that will get submitted */
if (!tgt_clone)
tgt_clone = clone;
/*
* Account io->origin_bio to DM dev on behalf of target
* that took ownership of IO with DM_MAPIO_SUBMITTED.
*/
dm_start_io_acct(io, clone);
trace_block_bio_remap(tgt_clone, disk_devt(io->md->disk),
tio->old_sector);
submit_bio_noacct(tgt_clone);
}
EXPORT_SYMBOL_GPL(dm_submit_bio_remap);
static noinline void __set_swap_bios_limit(struct mapped_device *md, int latch)
{
mutex_lock(&md->swap_bios_lock);
while (latch < md->swap_bios) {
cond_resched();
down(&md->swap_bios_semaphore);
md->swap_bios--;
}
while (latch > md->swap_bios) {
cond_resched();
up(&md->swap_bios_semaphore);
md->swap_bios++;
}
mutex_unlock(&md->swap_bios_lock);
}
static void __map_bio(struct bio *clone)
{
struct dm_target_io *tio = clone_to_tio(clone);
struct dm_target *ti = tio->ti;
struct dm_io *io = tio->io;
struct mapped_device *md = io->md;
int r;
clone->bi_end_io = clone_endio;
/*
* Map the clone.
*/
tio->old_sector = clone->bi_iter.bi_sector;
if (static_branch_unlikely(&swap_bios_enabled) &&
unlikely(swap_bios_limit(ti, clone))) {
int latch = get_swap_bios();
if (unlikely(latch != md->swap_bios))
__set_swap_bios_limit(md, latch);
down(&md->swap_bios_semaphore);
}
if (static_branch_unlikely(&zoned_enabled)) {
/*
* Check if the IO needs a special mapping due to zone append
* emulation on zoned target. In this case, dm_zone_map_bio()
* calls the target map operation.
*/
if (unlikely(dm_emulate_zone_append(md)))
r = dm_zone_map_bio(tio);
else
r = ti->type->map(ti, clone);
} else
r = ti->type->map(ti, clone);
switch (r) {
case DM_MAPIO_SUBMITTED:
/* target has assumed ownership of this io */
if (!ti->accounts_remapped_io)
dm_start_io_acct(io, clone);
break;
case DM_MAPIO_REMAPPED:
dm_submit_bio_remap(clone, NULL);
break;
case DM_MAPIO_KILL:
case DM_MAPIO_REQUEUE:
if (static_branch_unlikely(&swap_bios_enabled) &&
unlikely(swap_bios_limit(ti, clone)))
up(&md->swap_bios_semaphore);
free_tio(clone);
if (r == DM_MAPIO_KILL)
dm_io_dec_pending(io, BLK_STS_IOERR);
else
dm_io_dec_pending(io, BLK_STS_DM_REQUEUE);
break;
default:
DMCRIT("unimplemented target map return value: %d", r);
BUG();
}
}
static void setup_split_accounting(struct clone_info *ci, unsigned len)
{
struct dm_io *io = ci->io;
if (ci->sector_count > len) {
/*
* Split needed, save the mapped part for accounting.
* NOTE: dm_accept_partial_bio() will update accordingly.
*/
dm_io_set_flag(io, DM_IO_WAS_SPLIT);
io->sectors = len;
io->sector_offset = bio_sectors(ci->bio);
}
}
static void alloc_multiple_bios(struct bio_list *blist, struct clone_info *ci,
struct dm_target *ti, unsigned num_bios)
{
struct bio *bio;
int try;
for (try = 0; try < 2; try++) {
int bio_nr;
if (try)
mutex_lock(&ci->io->md->table_devices_lock);
for (bio_nr = 0; bio_nr < num_bios; bio_nr++) {
bio = alloc_tio(ci, ti, bio_nr, NULL,
try ? GFP_NOIO : GFP_NOWAIT);
if (!bio)
break;
bio_list_add(blist, bio);
}
if (try)
mutex_unlock(&ci->io->md->table_devices_lock);
if (bio_nr == num_bios)
return;
while ((bio = bio_list_pop(blist)))
free_tio(bio);
}
}
static int __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti,
unsigned int num_bios, unsigned *len)
{
struct bio_list blist = BIO_EMPTY_LIST;
struct bio *clone;
unsigned int ret = 0;
switch (num_bios) {
case 0:
break;
case 1:
if (len)
setup_split_accounting(ci, *len);
clone = alloc_tio(ci, ti, 0, len, GFP_NOIO);
__map_bio(clone);
ret = 1;
break;
default:
/* dm_accept_partial_bio() is not supported with shared tio->len_ptr */
alloc_multiple_bios(&blist, ci, ti, num_bios);
while ((clone = bio_list_pop(&blist))) {
dm_tio_set_flag(clone_to_tio(clone), DM_TIO_IS_DUPLICATE_BIO);
__map_bio(clone);
ret += 1;
}
break;
}
return ret;
}
static void __send_empty_flush(struct clone_info *ci)
{
struct dm_table *t = ci->map;
struct bio flush_bio;
/*
* Use an on-stack bio for this, it's safe since we don't
* need to reference it after submit. It's just used as
* the basis for the clone(s).
*/
bio_init(&flush_bio, ci->io->md->disk->part0, NULL, 0,
REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC);
ci->bio = &flush_bio;
ci->sector_count = 0;
ci->io->tio.clone.bi_iter.bi_size = 0;
for (unsigned int i = 0; i < t->num_targets; i++) {
unsigned int bios;
struct dm_target *ti = dm_table_get_target(t, i);
atomic_add(ti->num_flush_bios, &ci->io->io_count);
bios = __send_duplicate_bios(ci, ti, ti->num_flush_bios, NULL);
atomic_sub(ti->num_flush_bios - bios, &ci->io->io_count);
}
/*
* alloc_io() takes one extra reference for submission, so the
* reference won't reach 0 without the following subtraction
*/
atomic_sub(1, &ci->io->io_count);
bio_uninit(ci->bio);
}
static void __send_changing_extent_only(struct clone_info *ci, struct dm_target *ti,
unsigned num_bios)
{
unsigned len;
unsigned int bios;
len = min_t(sector_t, ci->sector_count,
max_io_len_target_boundary(ti, dm_target_offset(ti, ci->sector)));
atomic_add(num_bios, &ci->io->io_count);
bios = __send_duplicate_bios(ci, ti, num_bios, &len);
/*
* alloc_io() takes one extra reference for submission, so the
* reference won't reach 0 without the following (+1) subtraction
*/
atomic_sub(num_bios - bios + 1, &ci->io->io_count);
ci->sector += len;
ci->sector_count -= len;
}
static bool is_abnormal_io(struct bio *bio)
{
enum req_op op = bio_op(bio);
if (op != REQ_OP_READ && op != REQ_OP_WRITE && op != REQ_OP_FLUSH) {
switch (op) {
case REQ_OP_DISCARD:
case REQ_OP_SECURE_ERASE:
case REQ_OP_WRITE_ZEROES:
return true;
default:
break;
}
}
return false;
}
static blk_status_t __process_abnormal_io(struct clone_info *ci,
struct dm_target *ti)
{
unsigned num_bios = 0;
switch (bio_op(ci->bio)) {
case REQ_OP_DISCARD:
num_bios = ti->num_discard_bios;
break;
case REQ_OP_SECURE_ERASE:
num_bios = ti->num_secure_erase_bios;
break;
case REQ_OP_WRITE_ZEROES:
num_bios = ti->num_write_zeroes_bios;
break;
default:
break;
}
/*
* Even though the device advertised support for this type of
* request, that does not mean every target supports it, and
* reconfiguration might also have changed that since the
* check was performed.
*/
if (unlikely(!num_bios))
return BLK_STS_NOTSUPP;
__send_changing_extent_only(ci, ti, num_bios);
return BLK_STS_OK;
}
/*
* Reuse ->bi_private as dm_io list head for storing all dm_io instances
* associated with this bio, and this bio's bi_private needs to be
* stored in dm_io->data before the reuse.
*
* bio->bi_private is owned by fs or upper layer, so block layer won't
* touch it after splitting. Meantime it won't be changed by anyone after
* bio is submitted. So this reuse is safe.
*/
static inline struct dm_io **dm_poll_list_head(struct bio *bio)
{
return (struct dm_io **)&bio->bi_private;
}
static void dm_queue_poll_io(struct bio *bio, struct dm_io *io)
{
struct dm_io **head = dm_poll_list_head(bio);
if (!(bio->bi_opf & REQ_DM_POLL_LIST)) {
bio->bi_opf |= REQ_DM_POLL_LIST;
/*
* Save .bi_private into dm_io, so that we can reuse
* .bi_private as dm_io list head for storing dm_io list
*/
io->data = bio->bi_private;
/* tell block layer to poll for completion */
bio->bi_cookie = ~BLK_QC_T_NONE;
io->next = NULL;
} else {
/*
* bio recursed due to split, reuse original poll list,
* and save bio->bi_private too.
*/
io->data = (*head)->data;
io->next = *head;
}
*head = io;
}
/*
* Select the correct strategy for processing a non-flush bio.
*/
static blk_status_t __split_and_process_bio(struct clone_info *ci)
{
struct bio *clone;
struct dm_target *ti;
unsigned len;
ti = dm_table_find_target(ci->map, ci->sector);
if (unlikely(!ti))
return BLK_STS_IOERR;
if (unlikely((ci->bio->bi_opf & REQ_NOWAIT) != 0) &&
unlikely(!dm_target_supports_nowait(ti->type)))
return BLK_STS_NOTSUPP;
if (unlikely(ci->is_abnormal_io))
return __process_abnormal_io(ci, ti);
/*
* Only support bio polling for normal IO, and the target io is
* exactly inside the dm_io instance (verified in dm_poll_dm_io)
*/
ci->submit_as_polled = !!(ci->bio->bi_opf & REQ_POLLED);
len = min_t(sector_t, max_io_len(ti, ci->sector), ci->sector_count);
setup_split_accounting(ci, len);
clone = alloc_tio(ci, ti, 0, &len, GFP_NOIO);
__map_bio(clone);
ci->sector += len;
ci->sector_count -= len;
return BLK_STS_OK;
}
static void init_clone_info(struct clone_info *ci, struct mapped_device *md,
struct dm_table *map, struct bio *bio, bool is_abnormal)
{
ci->map = map;
ci->io = alloc_io(md, bio);
ci->bio = bio;
ci->is_abnormal_io = is_abnormal;
ci->submit_as_polled = false;
ci->sector = bio->bi_iter.bi_sector;
ci->sector_count = bio_sectors(bio);
/* Shouldn't happen but sector_count was being set to 0 so... */
if (static_branch_unlikely(&zoned_enabled) &&
WARN_ON_ONCE(op_is_zone_mgmt(bio_op(bio)) && ci->sector_count))
ci->sector_count = 0;
}
/*
* Entry point to split a bio into clones and submit them to the targets.
*/
static void dm_split_and_process_bio(struct mapped_device *md,
struct dm_table *map, struct bio *bio)
{
struct clone_info ci;
struct dm_io *io;
blk_status_t error = BLK_STS_OK;
bool is_abnormal;
is_abnormal = is_abnormal_io(bio);
if (unlikely(is_abnormal)) {
/*
* Use bio_split_to_limits() for abnormal IO (e.g. discard, etc)
* otherwise associated queue_limits won't be imposed.
*/
bio = bio_split_to_limits(bio);
}
init_clone_info(&ci, md, map, bio, is_abnormal);
io = ci.io;
if (bio->bi_opf & REQ_PREFLUSH) {
__send_empty_flush(&ci);
/* dm_io_complete submits any data associated with flush */
goto out;
}
error = __split_and_process_bio(&ci);
if (error || !ci.sector_count)
goto out;
/*
* Remainder must be passed to submit_bio_noacct() so it gets handled
* *after* bios already submitted have been completely processed.
*/
bio_trim(bio, io->sectors, ci.sector_count);
trace_block_split(bio, bio->bi_iter.bi_sector);
bio_inc_remaining(bio);
submit_bio_noacct(bio);
out:
/*
* Drop the extra reference count for non-POLLED bio, and hold one
* reference for POLLED bio, which will be released in dm_poll_bio
*
* Add every dm_io instance into the dm_io list head which is stored
* in bio->bi_private, so that dm_poll_bio can poll them all.
*/
if (error || !ci.submit_as_polled) {
/*
* In case of submission failure, the extra reference for
* submitting io isn't consumed yet
*/
if (error)
atomic_dec(&io->io_count);
dm_io_dec_pending(io, error);
} else
dm_queue_poll_io(bio, io);
}
static void dm_submit_bio(struct bio *bio)
{
struct mapped_device *md = bio->bi_bdev->bd_disk->private_data;
int srcu_idx;
struct dm_table *map;
blk_opf_t bio_opf = bio->bi_opf;
map = dm_get_live_table_bio(md, &srcu_idx, bio_opf);
/* If suspended, or map not yet available, queue this IO for later */
if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) ||
unlikely(!map)) {
if (bio->bi_opf & REQ_NOWAIT)
bio_wouldblock_error(bio);
else if (bio->bi_opf & REQ_RAHEAD)
bio_io_error(bio);
else
queue_io(md, bio);
goto out;
}
dm_split_and_process_bio(md, map, bio);
out:
dm_put_live_table_bio(md, srcu_idx, bio_opf);
}
static bool dm_poll_dm_io(struct dm_io *io, struct io_comp_batch *iob,
unsigned int flags)
{
WARN_ON_ONCE(!dm_tio_is_normal(&io->tio));
/* don't poll if the mapped io is done */
if (atomic_read(&io->io_count) > 1)
bio_poll(&io->tio.clone, iob, flags);
/* bio_poll holds the last reference */
return atomic_read(&io->io_count) == 1;
}
static int dm_poll_bio(struct bio *bio, struct io_comp_batch *iob,
unsigned int flags)
{
struct dm_io **head = dm_poll_list_head(bio);
struct dm_io *list = *head;
struct dm_io *tmp = NULL;
struct dm_io *curr, *next;
/* Only poll normal bio which was marked as REQ_DM_POLL_LIST */
if (!(bio->bi_opf & REQ_DM_POLL_LIST))
return 0;
WARN_ON_ONCE(!list);
/*
* Restore .bi_private before possibly completing dm_io.
*
* bio_poll() is only possible once @bio has been completely
* submitted via submit_bio_noacct()'s depth-first submission.
* So there is no dm_queue_poll_io() race associated with
* clearing REQ_DM_POLL_LIST here.
*/
bio->bi_opf &= ~REQ_DM_POLL_LIST;
bio->bi_private = list->data;
for (curr = list, next = curr->next; curr; curr = next, next =
curr ? curr->next : NULL) {
if (dm_poll_dm_io(curr, iob, flags)) {
/*
* clone_endio() has already occurred, so no
* error handling is needed here.
*/
__dm_io_dec_pending(curr);
} else {
curr->next = tmp;
tmp = curr;
}
}
/* Not done? */
if (tmp) {
bio->bi_opf |= REQ_DM_POLL_LIST;
/* Reset bio->bi_private to dm_io list head */
*head = tmp;
return 0;
}
return 1;
}
/*-----------------------------------------------------------------
* An IDR is used to keep track of allocated minor numbers.
*---------------------------------------------------------------*/
static void free_minor(int minor)
{
spin_lock(&_minor_lock);
idr_remove(&_minor_idr, minor);
spin_unlock(&_minor_lock);
}
/*
* See if the device with a specific minor # is free.
*/
static int specific_minor(int minor)
{
int r;
if (minor >= (1 << MINORBITS))
return -EINVAL;
idr_preload(GFP_KERNEL);
spin_lock(&_minor_lock);
r = idr_alloc(&_minor_idr, MINOR_ALLOCED, minor, minor + 1, GFP_NOWAIT);
spin_unlock(&_minor_lock);
idr_preload_end();
if (r < 0)
return r == -ENOSPC ? -EBUSY : r;
return 0;
}
static int next_free_minor(int *minor)
{
int r;
idr_preload(GFP_KERNEL);
spin_lock(&_minor_lock);
r = idr_alloc(&_minor_idr, MINOR_ALLOCED, 0, 1 << MINORBITS, GFP_NOWAIT);
spin_unlock(&_minor_lock);
idr_preload_end();
if (r < 0)
return r;
*minor = r;
return 0;
}
static const struct block_device_operations dm_blk_dops;
static const struct block_device_operations dm_rq_blk_dops;
static const struct dax_operations dm_dax_ops;
static void dm_wq_work(struct work_struct *work);
#ifdef CONFIG_BLK_INLINE_ENCRYPTION
static void dm_queue_destroy_crypto_profile(struct request_queue *q)
{
dm_destroy_crypto_profile(q->crypto_profile);
}
#else /* CONFIG_BLK_INLINE_ENCRYPTION */
static inline void dm_queue_destroy_crypto_profile(struct request_queue *q)
{
}
#endif /* !CONFIG_BLK_INLINE_ENCRYPTION */
static void cleanup_mapped_device(struct mapped_device *md)
{
if (md->wq)
destroy_workqueue(md->wq);
dm_free_md_mempools(md->mempools);
if (md->dax_dev) {
dax_remove_host(md->disk);
kill_dax(md->dax_dev);
put_dax(md->dax_dev);
md->dax_dev = NULL;
}
dm_cleanup_zoned_dev(md);
if (md->disk) {
spin_lock(&_minor_lock);
md->disk->private_data = NULL;
spin_unlock(&_minor_lock);
if (dm_get_md_type(md) != DM_TYPE_NONE) {
struct table_device *td;
dm_sysfs_exit(md);
list_for_each_entry(td, &md->table_devices, list) {
bd_unlink_disk_holder(td->dm_dev.bdev,
md->disk);
}
/*
* Hold lock to make sure del_gendisk() won't concurrent
* with open/close_table_device().
*/
mutex_lock(&md->table_devices_lock);
del_gendisk(md->disk);
mutex_unlock(&md->table_devices_lock);
}
dm_queue_destroy_crypto_profile(md->queue);
put_disk(md->disk);
}
if (md->pending_io) {
free_percpu(md->pending_io);
md->pending_io = NULL;
}
cleanup_srcu_struct(&md->io_barrier);
mutex_destroy(&md->suspend_lock);
mutex_destroy(&md->type_lock);
mutex_destroy(&md->table_devices_lock);
mutex_destroy(&md->swap_bios_lock);
dm_mq_cleanup_mapped_device(md);
}
/*
* Allocate and initialise a blank device with a given minor.
*/
static struct mapped_device *alloc_dev(int minor)
{
int r, numa_node_id = dm_get_numa_node();
struct mapped_device *md;
void *old_md;
md = kvzalloc_node(sizeof(*md), GFP_KERNEL, numa_node_id);
if (!md) {
DMERR("unable to allocate device, out of memory.");
return NULL;
}
if (!try_module_get(THIS_MODULE))
goto bad_module_get;
/* get a minor number for the dev */
if (minor == DM_ANY_MINOR)
r = next_free_minor(&minor);
else
r = specific_minor(minor);
if (r < 0)
goto bad_minor;
r = init_srcu_struct(&md->io_barrier);
if (r < 0)
goto bad_io_barrier;
md->numa_node_id = numa_node_id;
md->init_tio_pdu = false;
md->type = DM_TYPE_NONE;
mutex_init(&md->suspend_lock);
mutex_init(&md->type_lock);
mutex_init(&md->table_devices_lock);
spin_lock_init(&md->deferred_lock);
atomic_set(&md->holders, 1);
atomic_set(&md->open_count, 0);
atomic_set(&md->event_nr, 0);
atomic_set(&md->uevent_seq, 0);
INIT_LIST_HEAD(&md->uevent_list);
INIT_LIST_HEAD(&md->table_devices);
spin_lock_init(&md->uevent_lock);
/*
* default to bio-based until DM table is loaded and md->type
* established. If request-based table is loaded: blk-mq will
* override accordingly.
*/
md->disk = blk_alloc_disk(md->numa_node_id);
if (!md->disk)
goto bad;
md->queue = md->disk->queue;
init_waitqueue_head(&md->wait);
INIT_WORK(&md->work, dm_wq_work);
INIT_WORK(&md->requeue_work, dm_wq_requeue_work);
init_waitqueue_head(&md->eventq);
init_completion(&md->kobj_holder.completion);
md->requeue_list = NULL;
md->swap_bios = get_swap_bios();
sema_init(&md->swap_bios_semaphore, md->swap_bios);
mutex_init(&md->swap_bios_lock);
md->disk->major = _major;
md->disk->first_minor = minor;
md->disk->minors = 1;
md->disk->flags |= GENHD_FL_NO_PART;
md->disk->fops = &dm_blk_dops;
md->disk->private_data = md;
sprintf(md->disk->disk_name, "dm-%d", minor);
if (IS_ENABLED(CONFIG_FS_DAX)) {
md->dax_dev = alloc_dax(md, &dm_dax_ops);
if (IS_ERR(md->dax_dev)) {
md->dax_dev = NULL;
goto bad;
}
set_dax_nocache(md->dax_dev);
set_dax_nomc(md->dax_dev);
if (dax_add_host(md->dax_dev, md->disk))
goto bad;
}
format_dev_t(md->name, MKDEV(_major, minor));
md->wq = alloc_workqueue("kdmflush/%s", WQ_MEM_RECLAIM, 0, md->name);
if (!md->wq)
goto bad;
md->pending_io = alloc_percpu(unsigned long);
if (!md->pending_io)
goto bad;
dm_stats_init(&md->stats);
/* Populate the mapping, nobody knows we exist yet */
spin_lock(&_minor_lock);
old_md = idr_replace(&_minor_idr, md, minor);
spin_unlock(&_minor_lock);
BUG_ON(old_md != MINOR_ALLOCED);
return md;
bad:
cleanup_mapped_device(md);
bad_io_barrier:
free_minor(minor);
bad_minor:
module_put(THIS_MODULE);
bad_module_get:
kvfree(md);
return NULL;
}
static void unlock_fs(struct mapped_device *md);
static void free_dev(struct mapped_device *md)
{
int minor = MINOR(disk_devt(md->disk));
unlock_fs(md);
cleanup_mapped_device(md);
WARN_ON_ONCE(!list_empty(&md->table_devices));
dm_stats_cleanup(&md->stats);
free_minor(minor);
module_put(THIS_MODULE);
kvfree(md);
}
/*
* Bind a table to the device.
*/
static void event_callback(void *context)
{
unsigned long flags;
LIST_HEAD(uevents);
struct mapped_device *md = (struct mapped_device *) context;
spin_lock_irqsave(&md->uevent_lock, flags);
list_splice_init(&md->uevent_list, &uevents);
spin_unlock_irqrestore(&md->uevent_lock, flags);
dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj);
atomic_inc(&md->event_nr);
wake_up(&md->eventq);
dm_issue_global_event();
}
/*
* Returns old map, which caller must destroy.
*/
static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
struct queue_limits *limits)
{
struct dm_table *old_map;
sector_t size;
int ret;
lockdep_assert_held(&md->suspend_lock);
size = dm_table_get_size(t);
/*
* Wipe any geometry if the size of the table changed.
*/
if (size != dm_get_size(md))
memset(&md->geometry, 0, sizeof(md->geometry));
if (!get_capacity(md->disk))
set_capacity(md->disk, size);
else
set_capacity_and_notify(md->disk, size);
dm_table_event_callback(t, event_callback, md);
if (dm_table_request_based(t)) {
/*
* Leverage the fact that request-based DM targets are
* immutable singletons - used to optimize dm_mq_queue_rq.
*/
md->immutable_target = dm_table_get_immutable_target(t);
/*
* There is no need to reload with request-based dm because the
* size of front_pad doesn't change.
*
* Note for future: If you are to reload bioset, prep-ed
* requests in the queue may refer to bio from the old bioset,
* so you must walk through the queue to unprep.
*/
if (!md->mempools) {
md->mempools = t->mempools;
t->mempools = NULL;
}
} else {
/*
* The md may already have mempools that need changing.
* If so, reload bioset because front_pad may have changed
* because a different table was loaded.
*/
dm_free_md_mempools(md->mempools);
md->mempools = t->mempools;
t->mempools = NULL;
}
ret = dm_table_set_restrictions(t, md->queue, limits);
if (ret) {
old_map = ERR_PTR(ret);
goto out;
}
old_map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
rcu_assign_pointer(md->map, (void *)t);
md->immutable_target_type = dm_table_get_immutable_target_type(t);
if (old_map)
dm_sync_table(md);
out:
return old_map;
}
/*
* Returns unbound table for the caller to free.
*/
static struct dm_table *__unbind(struct mapped_device *md)
{
struct dm_table *map = rcu_dereference_protected(md->map, 1);
if (!map)
return NULL;
dm_table_event_callback(map, NULL, NULL);
RCU_INIT_POINTER(md->map, NULL);
dm_sync_table(md);
return map;
}
/*
* Constructor for a new device.
*/
int dm_create(int minor, struct mapped_device **result)
{
struct mapped_device *md;
md = alloc_dev(minor);
if (!md)
return -ENXIO;
dm_ima_reset_data(md);
*result = md;
return 0;
}
/*
* Functions to manage md->type.
* All are required to hold md->type_lock.
*/
void dm_lock_md_type(struct mapped_device *md)
{
mutex_lock(&md->type_lock);
}
void dm_unlock_md_type(struct mapped_device *md)
{
mutex_unlock(&md->type_lock);
}
void dm_set_md_type(struct mapped_device *md, enum dm_queue_mode type)
{
BUG_ON(!mutex_is_locked(&md->type_lock));
md->type = type;
}
enum dm_queue_mode dm_get_md_type(struct mapped_device *md)
{
return md->type;
}
struct target_type *dm_get_immutable_target_type(struct mapped_device *md)
{
return md->immutable_target_type;
}
/*
* The queue_limits are only valid as long as you have a reference
* count on 'md'.
*/
struct queue_limits *dm_get_queue_limits(struct mapped_device *md)
{
BUG_ON(!atomic_read(&md->holders));
return &md->queue->limits;
}
EXPORT_SYMBOL_GPL(dm_get_queue_limits);
/*
* Setup the DM device's queue based on md's type
*/
int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t)
{
enum dm_queue_mode type = dm_table_get_type(t);
struct queue_limits limits;
struct table_device *td;
int r;
switch (type) {
case DM_TYPE_REQUEST_BASED:
md->disk->fops = &dm_rq_blk_dops;
r = dm_mq_init_request_queue(md, t);
if (r) {
DMERR("Cannot initialize queue for request-based dm mapped device");
return r;
}
break;
case DM_TYPE_BIO_BASED:
case DM_TYPE_DAX_BIO_BASED:
break;
case DM_TYPE_NONE:
WARN_ON_ONCE(true);
break;
}
r = dm_calculate_queue_limits(t, &limits);
if (r) {
DMERR("Cannot calculate initial queue limits");
return r;
}
r = dm_table_set_restrictions(t, md->queue, &limits);
if (r)
return r;
/*
* Hold lock to make sure add_disk() and del_gendisk() won't concurrent
* with open_table_device() and close_table_device().
*/
mutex_lock(&md->table_devices_lock);
r = add_disk(md->disk);
mutex_unlock(&md->table_devices_lock);
if (r)
return r;
/*
* Register the holder relationship for devices added before the disk
* was live.
*/
list_for_each_entry(td, &md->table_devices, list) {
r = bd_link_disk_holder(td->dm_dev.bdev, md->disk);
if (r)
goto out_undo_holders;
}
r = dm_sysfs_init(md);
if (r)
goto out_undo_holders;
md->type = type;
return 0;
out_undo_holders:
list_for_each_entry_continue_reverse(td, &md->table_devices, list)
bd_unlink_disk_holder(td->dm_dev.bdev, md->disk);
mutex_lock(&md->table_devices_lock);
del_gendisk(md->disk);
mutex_unlock(&md->table_devices_lock);
return r;
}
struct mapped_device *dm_get_md(dev_t dev)
{
struct mapped_device *md;
unsigned minor = MINOR(dev);
if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
return NULL;
spin_lock(&_minor_lock);
md = idr_find(&_minor_idr, minor);
if (!md || md == MINOR_ALLOCED || (MINOR(disk_devt(dm_disk(md))) != minor) ||
test_bit(DMF_FREEING, &md->flags) || dm_deleting_md(md)) {
md = NULL;
goto out;
}
dm_get(md);
out:
spin_unlock(&_minor_lock);
return md;
}
EXPORT_SYMBOL_GPL(dm_get_md);
void *dm_get_mdptr(struct mapped_device *md)
{
return md->interface_ptr;
}
void dm_set_mdptr(struct mapped_device *md, void *ptr)
{
md->interface_ptr = ptr;
}
void dm_get(struct mapped_device *md)
{
atomic_inc(&md->holders);
BUG_ON(test_bit(DMF_FREEING, &md->flags));
}
int dm_hold(struct mapped_device *md)
{
spin_lock(&_minor_lock);
if (test_bit(DMF_FREEING, &md->flags)) {
spin_unlock(&_minor_lock);
return -EBUSY;
}
dm_get(md);
spin_unlock(&_minor_lock);
return 0;
}
EXPORT_SYMBOL_GPL(dm_hold);
const char *dm_device_name(struct mapped_device *md)
{
return md->name;
}
EXPORT_SYMBOL_GPL(dm_device_name);
static void __dm_destroy(struct mapped_device *md, bool wait)
{
struct dm_table *map;
int srcu_idx;
might_sleep();
spin_lock(&_minor_lock);
idr_replace(&_minor_idr, MINOR_ALLOCED, MINOR(disk_devt(dm_disk(md))));
set_bit(DMF_FREEING, &md->flags);
spin_unlock(&_minor_lock);
blk_mark_disk_dead(md->disk);
/*
* Take suspend_lock so that presuspend and postsuspend methods
* do not race with internal suspend.
*/
mutex_lock(&md->suspend_lock);
map = dm_get_live_table(md, &srcu_idx);
if (!dm_suspended_md(md)) {
dm_table_presuspend_targets(map);
set_bit(DMF_SUSPENDED, &md->flags);
set_bit(DMF_POST_SUSPENDING, &md->flags);
dm_table_postsuspend_targets(map);
}
/* dm_put_live_table must be before msleep, otherwise deadlock is possible */
dm_put_live_table(md, srcu_idx);
mutex_unlock(&md->suspend_lock);
/*
* Rare, but there may be I/O requests still going to complete,
* for example. Wait for all references to disappear.
* No one should increment the reference count of the mapped_device,
* after the mapped_device state becomes DMF_FREEING.
*/
if (wait)
while (atomic_read(&md->holders))
msleep(1);
else if (atomic_read(&md->holders))
DMWARN("%s: Forcibly removing mapped_device still in use! (%d users)",
dm_device_name(md), atomic_read(&md->holders));
dm_table_destroy(__unbind(md));
free_dev(md);
}
void dm_destroy(struct mapped_device *md)
{
__dm_destroy(md, true);
}
void dm_destroy_immediate(struct mapped_device *md)
{
__dm_destroy(md, false);
}
void dm_put(struct mapped_device *md)
{
atomic_dec(&md->holders);
}
EXPORT_SYMBOL_GPL(dm_put);
static bool dm_in_flight_bios(struct mapped_device *md)
{
int cpu;
unsigned long sum = 0;
for_each_possible_cpu(cpu)
sum += *per_cpu_ptr(md->pending_io, cpu);
return sum != 0;
}
static int dm_wait_for_bios_completion(struct mapped_device *md, unsigned int task_state)
{
int r = 0;
DEFINE_WAIT(wait);
while (true) {
prepare_to_wait(&md->wait, &wait, task_state);
if (!dm_in_flight_bios(md))
break;
if (signal_pending_state(task_state, current)) {
r = -EINTR;
break;
}
io_schedule();
}
finish_wait(&md->wait, &wait);
smp_rmb();
return r;
}
static int dm_wait_for_completion(struct mapped_device *md, unsigned int task_state)
{
int r = 0;
if (!queue_is_mq(md->queue))
return dm_wait_for_bios_completion(md, task_state);
while (true) {
if (!blk_mq_queue_inflight(md->queue))
break;
if (signal_pending_state(task_state, current)) {
r = -EINTR;
break;
}
msleep(5);
}
return r;
}
/*
* Process the deferred bios
*/
static void dm_wq_work(struct work_struct *work)
{
struct mapped_device *md = container_of(work, struct mapped_device, work);
struct bio *bio;
while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
spin_lock_irq(&md->deferred_lock);
bio = bio_list_pop(&md->deferred);
spin_unlock_irq(&md->deferred_lock);
if (!bio)
break;
submit_bio_noacct(bio);
}
}
static void dm_queue_flush(struct mapped_device *md)
{
clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
smp_mb__after_atomic();
queue_work(md->wq, &md->work);
}
/*
* Swap in a new table, returning the old one for the caller to destroy.
*/
struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
{
struct dm_table *live_map = NULL, *map = ERR_PTR(-EINVAL);
struct queue_limits limits;
int r;
mutex_lock(&md->suspend_lock);
/* device must be suspended */
if (!dm_suspended_md(md))
goto out;
/*
* If the new table has no data devices, retain the existing limits.
* This helps multipath with queue_if_no_path if all paths disappear,
* then new I/O is queued based on these limits, and then some paths
* reappear.
*/
if (dm_table_has_no_data_devices(table)) {
live_map = dm_get_live_table_fast(md);
if (live_map)
limits = md->queue->limits;
dm_put_live_table_fast(md);
}
if (!live_map) {
r = dm_calculate_queue_limits(table, &limits);
if (r) {
map = ERR_PTR(r);
goto out;
}
}
map = __bind(md, table, &limits);
dm_issue_global_event();
out:
mutex_unlock(&md->suspend_lock);
return map;
}
/*
* Functions to lock and unlock any filesystem running on the
* device.
*/
static int lock_fs(struct mapped_device *md)
{
int r;
WARN_ON(test_bit(DMF_FROZEN, &md->flags));
r = freeze_bdev(md->disk->part0);
if (!r)
set_bit(DMF_FROZEN, &md->flags);
return r;
}
static void unlock_fs(struct mapped_device *md)
{
if (!test_bit(DMF_FROZEN, &md->flags))
return;
thaw_bdev(md->disk->part0);
clear_bit(DMF_FROZEN, &md->flags);
}
/*
* @suspend_flags: DM_SUSPEND_LOCKFS_FLAG and/or DM_SUSPEND_NOFLUSH_FLAG
* @task_state: e.g. TASK_INTERRUPTIBLE or TASK_UNINTERRUPTIBLE
* @dmf_suspended_flag: DMF_SUSPENDED or DMF_SUSPENDED_INTERNALLY
*
* If __dm_suspend returns 0, the device is completely quiescent
* now. There is no request-processing activity. All new requests
* are being added to md->deferred list.
*/
static int __dm_suspend(struct mapped_device *md, struct dm_table *map,
unsigned suspend_flags, unsigned int task_state,
int dmf_suspended_flag)
{
bool do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG;
bool noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG;
int r;
lockdep_assert_held(&md->suspend_lock);
/*
* DMF_NOFLUSH_SUSPENDING must be set before presuspend.
* This flag is cleared before dm_suspend returns.
*/
if (noflush)
set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
else
DMDEBUG("%s: suspending with flush", dm_device_name(md));
/*
* This gets reverted if there's an error later and the targets
* provide the .presuspend_undo hook.
*/
dm_table_presuspend_targets(map);
/*
* Flush I/O to the device.
* Any I/O submitted after lock_fs() may not be flushed.
* noflush takes precedence over do_lockfs.
* (lock_fs() flushes I/Os and waits for them to complete.)
*/
if (!noflush && do_lockfs) {
r = lock_fs(md);
if (r) {
dm_table_presuspend_undo_targets(map);
return r;
}
}
/*
* Here we must make sure that no processes are submitting requests
* to target drivers i.e. no one may be executing
* dm_split_and_process_bio from dm_submit_bio.
*
* To get all processes out of dm_split_and_process_bio in dm_submit_bio,
* we take the write lock. To prevent any process from reentering
* dm_split_and_process_bio from dm_submit_bio and quiesce the thread
* (dm_wq_work), we set DMF_BLOCK_IO_FOR_SUSPEND and call
* flush_workqueue(md->wq).
*/
set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
if (map)
synchronize_srcu(&md->io_barrier);
/*
* Stop md->queue before flushing md->wq in case request-based
* dm defers requests to md->wq from md->queue.
*/
if (dm_request_based(md))
dm_stop_queue(md->queue);
flush_workqueue(md->wq);
/*
* At this point no more requests are entering target request routines.
* We call dm_wait_for_completion to wait for all existing requests
* to finish.
*/
r = dm_wait_for_completion(md, task_state);
if (!r)
set_bit(dmf_suspended_flag, &md->flags);
if (noflush)
clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
if (map)
synchronize_srcu(&md->io_barrier);
/* were we interrupted ? */
if (r < 0) {
dm_queue_flush(md);
if (dm_request_based(md))
dm_start_queue(md->queue);
unlock_fs(md);
dm_table_presuspend_undo_targets(map);
/* pushback list is already flushed, so skip flush */
}
return r;
}
/*
* We need to be able to change a mapping table under a mounted
* filesystem. For example we might want to move some data in
* the background. Before the table can be swapped with
* dm_bind_table, dm_suspend must be called to flush any in
* flight bios and ensure that any further io gets deferred.
*/
/*
* Suspend mechanism in request-based dm.
*
* 1. Flush all I/Os by lock_fs() if needed.
* 2. Stop dispatching any I/O by stopping the request_queue.
* 3. Wait for all in-flight I/Os to be completed or requeued.
*
* To abort suspend, start the request_queue.
*/
int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
{
struct dm_table *map = NULL;
int r = 0;
retry:
mutex_lock_nested(&md->suspend_lock, SINGLE_DEPTH_NESTING);
if (dm_suspended_md(md)) {
r = -EINVAL;
goto out_unlock;
}
if (dm_suspended_internally_md(md)) {
/* already internally suspended, wait for internal resume */
mutex_unlock(&md->suspend_lock);
r = wait_on_bit(&md->flags, DMF_SUSPENDED_INTERNALLY, TASK_INTERRUPTIBLE);
if (r)
return r;
goto retry;
}
map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
r = __dm_suspend(md, map, suspend_flags, TASK_INTERRUPTIBLE, DMF_SUSPENDED);
if (r)
goto out_unlock;
set_bit(DMF_POST_SUSPENDING, &md->flags);
dm_table_postsuspend_targets(map);
clear_bit(DMF_POST_SUSPENDING, &md->flags);
out_unlock:
mutex_unlock(&md->suspend_lock);
return r;
}
static int __dm_resume(struct mapped_device *md, struct dm_table *map)
{
if (map) {
int r = dm_table_resume_targets(map);
if (r)
return r;
}
dm_queue_flush(md);
/*
* Flushing deferred I/Os must be done after targets are resumed
* so that mapping of targets can work correctly.
* Request-based dm is queueing the deferred I/Os in its request_queue.
*/
if (dm_request_based(md))
dm_start_queue(md->queue);
unlock_fs(md);
return 0;
}
int dm_resume(struct mapped_device *md)
{
int r;
struct dm_table *map = NULL;
retry:
r = -EINVAL;
mutex_lock_nested(&md->suspend_lock, SINGLE_DEPTH_NESTING);
if (!dm_suspended_md(md))
goto out;
if (dm_suspended_internally_md(md)) {
/* already internally suspended, wait for internal resume */
mutex_unlock(&md->suspend_lock);
r = wait_on_bit(&md->flags, DMF_SUSPENDED_INTERNALLY, TASK_INTERRUPTIBLE);
if (r)
return r;
goto retry;
}
map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
if (!map || !dm_table_get_size(map))
goto out;
r = __dm_resume(md, map);
if (r)
goto out;
clear_bit(DMF_SUSPENDED, &md->flags);
out:
mutex_unlock(&md->suspend_lock);
return r;
}
/*
* Internal suspend/resume works like userspace-driven suspend. It waits
* until all bios finish and prevents issuing new bios to the target drivers.
* It may be used only from the kernel.
*/
static void __dm_internal_suspend(struct mapped_device *md, unsigned suspend_flags)
{
struct dm_table *map = NULL;
lockdep_assert_held(&md->suspend_lock);
if (md->internal_suspend_count++)
return; /* nested internal suspend */
if (dm_suspended_md(md)) {
set_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
return; /* nest suspend */
}
map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
/*
* Using TASK_UNINTERRUPTIBLE because only NOFLUSH internal suspend is
* supported. Properly supporting a TASK_INTERRUPTIBLE internal suspend
* would require changing .presuspend to return an error -- avoid this
* until there is a need for more elaborate variants of internal suspend.
*/
(void) __dm_suspend(md, map, suspend_flags, TASK_UNINTERRUPTIBLE,
DMF_SUSPENDED_INTERNALLY);
set_bit(DMF_POST_SUSPENDING, &md->flags);
dm_table_postsuspend_targets(map);
clear_bit(DMF_POST_SUSPENDING, &md->flags);
}
static void __dm_internal_resume(struct mapped_device *md)
{
BUG_ON(!md->internal_suspend_count);
if (--md->internal_suspend_count)
return; /* resume from nested internal suspend */
if (dm_suspended_md(md))
goto done; /* resume from nested suspend */
/*
* NOTE: existing callers don't need to call dm_table_resume_targets
* (which may fail -- so best to avoid it for now by passing NULL map)
*/
(void) __dm_resume(md, NULL);
done:
clear_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
smp_mb__after_atomic();
wake_up_bit(&md->flags, DMF_SUSPENDED_INTERNALLY);
}
void dm_internal_suspend_noflush(struct mapped_device *md)
{
mutex_lock(&md->suspend_lock);
__dm_internal_suspend(md, DM_SUSPEND_NOFLUSH_FLAG);
mutex_unlock(&md->suspend_lock);
}
EXPORT_SYMBOL_GPL(dm_internal_suspend_noflush);
void dm_internal_resume(struct mapped_device *md)
{
mutex_lock(&md->suspend_lock);
__dm_internal_resume(md);
mutex_unlock(&md->suspend_lock);
}
EXPORT_SYMBOL_GPL(dm_internal_resume);
/*
* Fast variants of internal suspend/resume hold md->suspend_lock,
* which prevents interaction with userspace-driven suspend.
*/
void dm_internal_suspend_fast(struct mapped_device *md)
{
mutex_lock(&md->suspend_lock);
if (dm_suspended_md(md) || dm_suspended_internally_md(md))
return;
set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
synchronize_srcu(&md->io_barrier);
flush_workqueue(md->wq);
dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
}
EXPORT_SYMBOL_GPL(dm_internal_suspend_fast);
void dm_internal_resume_fast(struct mapped_device *md)
{
if (dm_suspended_md(md) || dm_suspended_internally_md(md))
goto done;
dm_queue_flush(md);
done:
mutex_unlock(&md->suspend_lock);
}
EXPORT_SYMBOL_GPL(dm_internal_resume_fast);
/*-----------------------------------------------------------------
* Event notification.
*---------------------------------------------------------------*/
int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
unsigned cookie)
{
int r;
unsigned noio_flag;
char udev_cookie[DM_COOKIE_LENGTH];
char *envp[] = { udev_cookie, NULL };
noio_flag = memalloc_noio_save();
if (!cookie)
r = kobject_uevent(&disk_to_dev(md->disk)->kobj, action);
else {
snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u",
DM_COOKIE_ENV_VAR_NAME, cookie);
r = kobject_uevent_env(&disk_to_dev(md->disk)->kobj,
action, envp);
}
memalloc_noio_restore(noio_flag);
return r;
}
uint32_t dm_next_uevent_seq(struct mapped_device *md)
{
return atomic_add_return(1, &md->uevent_seq);
}
uint32_t dm_get_event_nr(struct mapped_device *md)
{
return atomic_read(&md->event_nr);
}
int dm_wait_event(struct mapped_device *md, int event_nr)
{
return wait_event_interruptible(md->eventq,
(event_nr != atomic_read(&md->event_nr)));
}
void dm_uevent_add(struct mapped_device *md, struct list_head *elist)
{
unsigned long flags;
spin_lock_irqsave(&md->uevent_lock, flags);
list_add(elist, &md->uevent_list);
spin_unlock_irqrestore(&md->uevent_lock, flags);
}
/*
* The gendisk is only valid as long as you have a reference
* count on 'md'.
*/
struct gendisk *dm_disk(struct mapped_device *md)
{
return md->disk;
}
EXPORT_SYMBOL_GPL(dm_disk);
struct kobject *dm_kobject(struct mapped_device *md)
{
return &md->kobj_holder.kobj;
}
struct mapped_device *dm_get_from_kobject(struct kobject *kobj)
{
struct mapped_device *md;
md = container_of(kobj, struct mapped_device, kobj_holder.kobj);
spin_lock(&_minor_lock);
if (test_bit(DMF_FREEING, &md->flags) || dm_deleting_md(md)) {
md = NULL;
goto out;
}
dm_get(md);
out:
spin_unlock(&_minor_lock);
return md;
}
int dm_suspended_md(struct mapped_device *md)
{
return test_bit(DMF_SUSPENDED, &md->flags);
}
static int dm_post_suspending_md(struct mapped_device *md)
{
return test_bit(DMF_POST_SUSPENDING, &md->flags);
}
int dm_suspended_internally_md(struct mapped_device *md)
{
return test_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
}
int dm_test_deferred_remove_flag(struct mapped_device *md)
{
return test_bit(DMF_DEFERRED_REMOVE, &md->flags);
}
int dm_suspended(struct dm_target *ti)
{
return dm_suspended_md(ti->table->md);
}
EXPORT_SYMBOL_GPL(dm_suspended);
int dm_post_suspending(struct dm_target *ti)
{
return dm_post_suspending_md(ti->table->md);
}
EXPORT_SYMBOL_GPL(dm_post_suspending);
int dm_noflush_suspending(struct dm_target *ti)
{
return __noflush_suspending(ti->table->md);
}
EXPORT_SYMBOL_GPL(dm_noflush_suspending);
void dm_free_md_mempools(struct dm_md_mempools *pools)
{
if (!pools)
return;
bioset_exit(&pools->bs);
bioset_exit(&pools->io_bs);
kfree(pools);
}
struct dm_pr {
u64 old_key;
u64 new_key;
u32 flags;
bool abort;
bool fail_early;
int ret;
enum pr_type type;
};
static int dm_call_pr(struct block_device *bdev, iterate_devices_callout_fn fn,
struct dm_pr *pr)
{
struct mapped_device *md = bdev->bd_disk->private_data;
struct dm_table *table;
struct dm_target *ti;
int ret = -ENOTTY, srcu_idx;
table = dm_get_live_table(md, &srcu_idx);
if (!table || !dm_table_get_size(table))
goto out;
/* We only support devices that have a single target */
if (table->num_targets != 1)
goto out;
ti = dm_table_get_target(table, 0);
if (dm_suspended_md(md)) {
ret = -EAGAIN;
goto out;
}
ret = -EINVAL;
if (!ti->type->iterate_devices)
goto out;
ti->type->iterate_devices(ti, fn, pr);
ret = 0;
out:
dm_put_live_table(md, srcu_idx);
return ret;
}
/*
* For register / unregister we need to manually call out to every path.
*/
static int __dm_pr_register(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
struct dm_pr *pr = data;
const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops;
int ret;
if (!ops || !ops->pr_register) {
pr->ret = -EOPNOTSUPP;
return -1;
}
ret = ops->pr_register(dev->bdev, pr->old_key, pr->new_key, pr->flags);
if (!ret)
return 0;
if (!pr->ret)
pr->ret = ret;
if (pr->fail_early)
return -1;
return 0;
}
static int dm_pr_register(struct block_device *bdev, u64 old_key, u64 new_key,
u32 flags)
{
struct dm_pr pr = {
.old_key = old_key,
.new_key = new_key,
.flags = flags,
.fail_early = true,
.ret = 0,
};
int ret;
ret = dm_call_pr(bdev, __dm_pr_register, &pr);
if (ret) {
/* Didn't even get to register a path */
return ret;
}
if (!pr.ret)
return 0;
ret = pr.ret;
if (!new_key)
return ret;
/* unregister all paths if we failed to register any path */
pr.old_key = new_key;
pr.new_key = 0;
pr.flags = 0;
pr.fail_early = false;
(void) dm_call_pr(bdev, __dm_pr_register, &pr);
return ret;
}
static int __dm_pr_reserve(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
struct dm_pr *pr = data;
const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops;
if (!ops || !ops->pr_reserve) {
pr->ret = -EOPNOTSUPP;
return -1;
}
pr->ret = ops->pr_reserve(dev->bdev, pr->old_key, pr->type, pr->flags);
if (!pr->ret)
return -1;
return 0;
}
static int dm_pr_reserve(struct block_device *bdev, u64 key, enum pr_type type,
u32 flags)
{
struct dm_pr pr = {
.old_key = key,
.flags = flags,
.type = type,
.fail_early = false,
.ret = 0,
};
int ret;
ret = dm_call_pr(bdev, __dm_pr_reserve, &pr);
if (ret)
return ret;
return pr.ret;
}
/*
* If there is a non-All Registrants type of reservation, the release must be
* sent down the holding path. For the cases where there is no reservation or
* the path is not the holder the device will also return success, so we must
* try each path to make sure we got the correct path.
*/
static int __dm_pr_release(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
struct dm_pr *pr = data;
const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops;
if (!ops || !ops->pr_release) {
pr->ret = -EOPNOTSUPP;
return -1;
}
pr->ret = ops->pr_release(dev->bdev, pr->old_key, pr->type);
if (pr->ret)
return -1;
return 0;
}
static int dm_pr_release(struct block_device *bdev, u64 key, enum pr_type type)
{
struct dm_pr pr = {
.old_key = key,
.type = type,
.fail_early = false,
};
int ret;
ret = dm_call_pr(bdev, __dm_pr_release, &pr);
if (ret)
return ret;
return pr.ret;
}
static int __dm_pr_preempt(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
struct dm_pr *pr = data;
const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops;
if (!ops || !ops->pr_preempt) {
pr->ret = -EOPNOTSUPP;
return -1;
}
pr->ret = ops->pr_preempt(dev->bdev, pr->old_key, pr->new_key, pr->type,
pr->abort);
if (!pr->ret)
return -1;
return 0;
}
static int dm_pr_preempt(struct block_device *bdev, u64 old_key, u64 new_key,
enum pr_type type, bool abort)
{
struct dm_pr pr = {
.new_key = new_key,
.old_key = old_key,
.type = type,
.fail_early = false,
};
int ret;
ret = dm_call_pr(bdev, __dm_pr_preempt, &pr);
if (ret)
return ret;
return pr.ret;
}
static int dm_pr_clear(struct block_device *bdev, u64 key)
{
struct mapped_device *md = bdev->bd_disk->private_data;
const struct pr_ops *ops;
int r, srcu_idx;
r = dm_prepare_ioctl(md, &srcu_idx, &bdev);
if (r < 0)
goto out;
ops = bdev->bd_disk->fops->pr_ops;
if (ops && ops->pr_clear)
r = ops->pr_clear(bdev, key);
else
r = -EOPNOTSUPP;
out:
dm_unprepare_ioctl(md, srcu_idx);
return r;
}
static const struct pr_ops dm_pr_ops = {
.pr_register = dm_pr_register,
.pr_reserve = dm_pr_reserve,
.pr_release = dm_pr_release,
.pr_preempt = dm_pr_preempt,
.pr_clear = dm_pr_clear,
};
static const struct block_device_operations dm_blk_dops = {
.submit_bio = dm_submit_bio,
.poll_bio = dm_poll_bio,
.open = dm_blk_open,
.release = dm_blk_close,
.ioctl = dm_blk_ioctl,
.getgeo = dm_blk_getgeo,
.report_zones = dm_blk_report_zones,
.pr_ops = &dm_pr_ops,
.owner = THIS_MODULE
};
static const struct block_device_operations dm_rq_blk_dops = {
.open = dm_blk_open,
.release = dm_blk_close,
.ioctl = dm_blk_ioctl,
.getgeo = dm_blk_getgeo,
.pr_ops = &dm_pr_ops,
.owner = THIS_MODULE
};
static const struct dax_operations dm_dax_ops = {
.direct_access = dm_dax_direct_access,
.zero_page_range = dm_dax_zero_page_range,
.recovery_write = dm_dax_recovery_write,
};
/*
* module hooks
*/
module_init(dm_init);
module_exit(dm_exit);
module_param(major, uint, 0);
MODULE_PARM_DESC(major, "The major number of the device mapper");
module_param(reserved_bio_based_ios, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(reserved_bio_based_ios, "Reserved IOs in bio-based mempools");
module_param(dm_numa_node, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(dm_numa_node, "NUMA node for DM device memory allocations");
module_param(swap_bios, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(swap_bios, "Maximum allowed inflight swap IOs");
MODULE_DESCRIPTION(DM_NAME " driver");
MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
MODULE_LICENSE("GPL");
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