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35 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Linus Torvalds
|
fd2ff2774e |
for-5.13-rc4-tag
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Merge tag 'for-5.13-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"Error handling improvements, caught by error injection:
- handle errors during checksum deletion
- set error on mapping when ordered extent io cannot be finished
- inode link count fixup in tree-log
- missing return value checks for inode updates in tree-log
- abort transaction in rename exchange if adding second reference
fails
Fixes:
- fix fsync failure after writes to prealloc extents
- fix deadlock when cloning inline extents and low on available space
- fix compressed writes that cross stripe boundary"
* tag 'for-5.13-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
MAINTAINERS: add btrfs IRC link
btrfs: fix deadlock when cloning inline extents and low on available space
btrfs: fix fsync failure and transaction abort after writes to prealloc extents
btrfs: abort in rename_exchange if we fail to insert the second ref
btrfs: check error value from btrfs_update_inode in tree log
btrfs: fixup error handling in fixup_inode_link_counts
btrfs: mark ordered extent and inode with error if we fail to finish
btrfs: return errors from btrfs_del_csums in cleanup_ref_head
btrfs: fix error handling in btrfs_del_csums
btrfs: fix compressed writes that cross stripe boundary
|
||
Filipe Manana
|
76a6d5cd74 |
btrfs: fix deadlock when cloning inline extents and low on available space
There are a few cases where cloning an inline extent requires copying data
into a page of the destination inode. For these cases we are allocating
the required data and metadata space while holding a leaf locked. This can
result in a deadlock when we are low on available space because allocating
the space may flush delalloc and two deadlock scenarios can happen:
1) When starting writeback for an inode with a very small dirty range that
fits in an inline extent, we deadlock during the writeback when trying
to insert the inline extent, at cow_file_range_inline(), if the extent
is going to be located in the leaf for which we are already holding a
read lock;
2) After successfully starting writeback, for non-inline extent cases,
the async reclaim thread will hang waiting for an ordered extent to
complete if the ordered extent completion needs to modify the leaf
for which the clone task is holding a read lock (for adding or
replacing file extent items). So the cloning task will wait forever
on the async reclaim thread to make progress, which in turn is
waiting for the ordered extent completion which in turn is waiting
to acquire a write lock on the same leaf.
So fix this by making sure we release the path (and therefore the leaf)
every time we need to copy the inline extent's data into a page of the
destination inode, as by that time we do not need to have the leaf locked.
Fixes:
|
||
|
Linus Torvalds
|
45af60e7ce |
for-5.13-rc2-tag
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||
|
Filipe Manana
|
6416954ca7 |
btrfs: release path before starting transaction when cloning inline extent
When cloning an inline extent there are a few cases, such as when we have an implicit hole at file offset 0, where we start a transaction while holding a read lock on a leaf. Starting the transaction results in a call to sb_start_intwrite(), which results in doing a read lock on a percpu semaphore. Lockdep doesn't like this and complains about it: [46.580704] ====================================================== [46.580752] WARNING: possible circular locking dependency detected [46.580799] 5.13.0-rc1 #28 Not tainted [46.580832] ------------------------------------------------------ [46.580877] cloner/3835 is trying to acquire lock: [46.580918] c00000001301d638 (sb_internal#2){.+.+}-{0:0}, at: clone_copy_inline_extent+0xe4/0x5a0 [46.581167] [46.581167] but task is already holding lock: [46.581217] c000000007fa2550 (btrfs-tree-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x70/0x1d0 [46.581293] [46.581293] which lock already depends on the new lock. [46.581293] [46.581351] [46.581351] the existing dependency chain (in reverse order) is: [46.581410] [46.581410] -> #1 (btrfs-tree-00){++++}-{3:3}: [46.581464] down_read_nested+0x68/0x200 [46.581536] __btrfs_tree_read_lock+0x70/0x1d0 [46.581577] btrfs_read_lock_root_node+0x88/0x200 [46.581623] btrfs_search_slot+0x298/0xb70 [46.581665] btrfs_set_inode_index+0xfc/0x260 [46.581708] btrfs_new_inode+0x26c/0x950 [46.581749] btrfs_create+0xf4/0x2b0 [46.581782] lookup_open.isra.57+0x55c/0x6a0 [46.581855] path_openat+0x418/0xd20 [46.581888] do_filp_open+0x9c/0x130 [46.581920] do_sys_openat2+0x2ec/0x430 [46.581961] do_sys_open+0x90/0xc0 [46.581993] system_call_exception+0x3d4/0x410 [46.582037] system_call_common+0xec/0x278 [46.582078] [46.582078] -> #0 (sb_internal#2){.+.+}-{0:0}: [46.582135] __lock_acquire+0x1e90/0x2c50 [46.582176] lock_acquire+0x2b4/0x5b0 [46.582263] start_transaction+0x3cc/0x950 [46.582308] clone_copy_inline_extent+0xe4/0x5a0 [46.582353] btrfs_clone+0x5fc/0x880 [46.582388] btrfs_clone_files+0xd8/0x1c0 [46.582434] btrfs_remap_file_range+0x3d8/0x590 [46.582481] do_clone_file_range+0x10c/0x270 [46.582558] vfs_clone_file_range+0x1b0/0x310 [46.582605] ioctl_file_clone+0x90/0x130 [46.582651] do_vfs_ioctl+0x874/0x1ac0 [46.582697] sys_ioctl+0x6c/0x120 [46.582733] system_call_exception+0x3d4/0x410 [46.582777] system_call_common+0xec/0x278 [46.582822] [46.582822] other info that might help us debug this: [46.582822] [46.582888] Possible unsafe locking scenario: [46.582888] [46.582942] CPU0 CPU1 [46.582984] ---- ---- [46.583028] lock(btrfs-tree-00); [46.583062] lock(sb_internal#2); [46.583119] lock(btrfs-tree-00); [46.583174] lock(sb_internal#2); [46.583212] [46.583212] *** DEADLOCK *** [46.583212] [46.583266] 6 locks held by cloner/3835: [46.583299] #0: c00000001301d448 (sb_writers#12){.+.+}-{0:0}, at: ioctl_file_clone+0x90/0x130 [46.583382] #1: c00000000f6d3768 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}, at: lock_two_nondirectories+0x58/0xc0 [46.583477] #2: c00000000f6d72a8 (&sb->s_type->i_mutex_key#15/4){+.+.}-{3:3}, at: lock_two_nondirectories+0x9c/0xc0 [46.583574] #3: c00000000f6d7138 (&ei->i_mmap_lock){+.+.}-{3:3}, at: btrfs_remap_file_range+0xd0/0x590 [46.583657] #4: c00000000f6d35f8 (&ei->i_mmap_lock/1){+.+.}-{3:3}, at: btrfs_remap_file_range+0xe0/0x590 [46.583743] #5: c000000007fa2550 (btrfs-tree-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x70/0x1d0 [46.583828] [46.583828] stack backtrace: [46.583872] CPU: 1 PID: 3835 Comm: cloner Not tainted 5.13.0-rc1 #28 [46.583931] Call Trace: [46.583955] [c0000000167c7200] [c000000000c1ee78] dump_stack+0xec/0x144 (unreliable) [46.584052] [c0000000167c7240] [c000000000274058] print_circular_bug.isra.32+0x3a8/0x400 [46.584123] [c0000000167c72e0] [c0000000002741f4] check_noncircular+0x144/0x190 [46.584191] [c0000000167c73b0] [c000000000278fc0] __lock_acquire+0x1e90/0x2c50 [46.584259] [c0000000167c74f0] [c00000000027aa94] lock_acquire+0x2b4/0x5b0 [46.584317] [c0000000167c75e0] [c000000000a0d6cc] start_transaction+0x3cc/0x950 [46.584388] [c0000000167c7690] [c000000000af47a4] clone_copy_inline_extent+0xe4/0x5a0 [46.584457] [c0000000167c77c0] [c000000000af525c] btrfs_clone+0x5fc/0x880 [46.584514] [c0000000167c7990] [c000000000af5698] btrfs_clone_files+0xd8/0x1c0 [46.584583] [c0000000167c7a00] [c000000000af5b58] btrfs_remap_file_range+0x3d8/0x590 [46.584652] [c0000000167c7ae0] [c0000000005d81dc] do_clone_file_range+0x10c/0x270 [46.584722] [c0000000167c7b40] [c0000000005d84f0] vfs_clone_file_range+0x1b0/0x310 [46.584793] [c0000000167c7bb0] [c00000000058bf80] ioctl_file_clone+0x90/0x130 [46.584861] [c0000000167c7c10] [c00000000058c894] do_vfs_ioctl+0x874/0x1ac0 [46.584922] [c0000000167c7d10] [c00000000058db4c] sys_ioctl+0x6c/0x120 [46.584978] [c0000000167c7d60] [c0000000000364a4] system_call_exception+0x3d4/0x410 [46.585046] [c0000000167c7e10] [c00000000000d45c] system_call_common+0xec/0x278 [46.585114] --- interrupt: c00 at 0x7ffff7e22990 [46.585160] NIP: 00007ffff7e22990 LR: 00000001000010ec CTR: 0000000000000000 [46.585224] REGS: c0000000167c7e80 TRAP: 0c00 Not tainted (5.13.0-rc1) [46.585280] MSR: 800000000280f033 <SF,VEC,VSX,EE,PR,FP,ME,IR,DR,RI,LE> CR: 28000244 XER: 00000000 [46.585374] IRQMASK: 0 [46.585374] GPR00: 0000000000000036 00007fffffffdec0 00007ffff7f17100 0000000000000004 [46.585374] GPR04: 000000008020940d 00007fffffffdf40 0000000000000000 0000000000000000 [46.585374] GPR08: 0000000000000004 0000000000000000 0000000000000000 0000000000000000 [46.585374] GPR12: 0000000000000000 00007ffff7ffa940 0000000000000000 0000000000000000 [46.585374] GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [46.585374] GPR20: 0000000000000000 000000009123683e 00007fffffffdf40 0000000000000000 [46.585374] GPR24: 0000000000000000 0000000000000000 0000000000000000 0000000000000004 [46.585374] GPR28: 0000000100030260 0000000100030280 0000000000000003 000000000000005f [46.585919] NIP [00007ffff7e22990] 0x7ffff7e22990 [46.585964] LR [00000001000010ec] 0x1000010ec [46.586010] --- interrupt: c00 This should be a false positive, as both locks are acquired in read mode. Nevertheless, we don't need to hold a leaf locked when we start the transaction, so just release the leaf (path) before starting it. Reported-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/linux-btrfs/20210513214404.xks77p566fglzgum@riteshh-domain/ Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
||
Ira Weiny
|
d048b9c2a7 |
btrfs: use memzero_page() instead of open coded kmap pattern
There are many places where kmap/memset/kunmap patterns occur. Use the newly lifted memzero_page() to eliminate direct uses of kmap and leverage the new core functions use of kmap_local_page(). The development of this patch was aided by the following coccinelle script: // <smpl> // SPDX-License-Identifier: GPL-2.0-only // Find kmap/memset/kunmap pattern and replace with memset*page calls // // NOTE: Offsets and other expressions may be more complex than what the script // will automatically generate. Therefore a catchall rule is provided to find // the pattern which then must be evaluated by hand. // // Confidence: Low // Copyright: (C) 2021 Intel Corporation // URL: http://coccinelle.lip6.fr/ // Comments: // Options: // // Then the memset pattern // @ memset_rule1 @ expression page, V, L, Off; identifier ptr; type VP; @@ ( -VP ptr = kmap(page); | -ptr = kmap(page); | -VP ptr = kmap_atomic(page); | -ptr = kmap_atomic(page); ) <+... ( -memset(ptr, 0, L); +memzero_page(page, 0, L); | -memset(ptr + Off, 0, L); +memzero_page(page, Off, L); | -memset(ptr, V, L); +memset_page(page, V, 0, L); | -memset(ptr + Off, V, L); +memset_page(page, V, Off, L); ) ...+> ( -kunmap(page); | -kunmap_atomic(ptr); ) // Remove any pointers left unused @ depends on memset_rule1 @ identifier memset_rule1.ptr; type VP, VP1; @@ -VP ptr; ... when != ptr; ? VP1 ptr; // // Catch all // @ memset_rule2 @ expression page; identifier ptr; expression GenTo, GenSize, GenValue; type VP; @@ ( -VP ptr = kmap(page); | -ptr = kmap(page); | -VP ptr = kmap_atomic(page); | -ptr = kmap_atomic(page); ) <+... ( // // Some call sites have complex expressions within the memset/memcpy // The follow are catch alls which need to be evaluated by hand. // -memset(GenTo, 0, GenSize); +memzero_pageExtra(page, GenTo, GenSize); | -memset(GenTo, GenValue, GenSize); +memset_pageExtra(page, GenValue, GenTo, GenSize); ) ...+> ( -kunmap(page); | -kunmap_atomic(ptr); ) // Remove any pointers left unused @ depends on memset_rule2 @ identifier memset_rule2.ptr; type VP, VP1; @@ -VP ptr; ... when != ptr; ? VP1 ptr; // </smpl> Link: https://lkml.kernel.org/r/20210309212137.2610186-4-ira.weiny@intel.com Signed-off-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: David Sterba <dsterba@suse.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Filipe Manana
|
b7a7a83463 |
btrfs: make reflinks respect O_SYNC O_DSYNC and S_SYNC flags
If we reflink to or from a file opened with O_SYNC/O_DSYNC or to/from a file that has the S_SYNC attribute set, we totally ignore that and do not durably persist the reflink changes. Since a reflink can change the data readable from a file (and mtime/ctime, or a file size), it makes sense to durably persist (fsync) the source and destination files/ranges. This was previously discussed at: https://lore.kernel.org/linux-btrfs/20200903035225.GJ6090@magnolia/ The recently introduced test case generic/628, from fstests, exercises these scenarios and currently fails without this change. So make sure we fsync the source and destination files/ranges when either of them was opened with O_SYNC/O_DSYNC or has the S_SYNC attribute set, just like XFS already does. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
||
Josef Bacik
|
8c99516a8c |
btrfs: exclude mmaps while doing remap
Darrick reported a potential issue to me where we could allow mmap
writes after validating a page range matched in the case of dedupe.
Generally we rely on lock page -> lock extent with the ordered flush to
protect us, but this is done after we check the pages because we use the
generic helpers, so we could modify the page in between doing the check
and locking the range.
There also exists a deadlock, as described by Filipe
"""
When cloning a file range, we lock the inodes, flush any delalloc within
the respective file ranges, wait for any ordered extents and then lock the
file ranges in both inodes. This means that right after we flush delalloc
and before we lock the file ranges, memory mapped writes can come in and
dirty pages in the file ranges of the clone operation.
Most of the time this is harmless and causes no problems. However, if we
are low on available metadata space, we can later end up in a deadlock
when starting a transaction to replace file extent items. This happens if
when allocating metadata space for the transaction, we need to wait for
the async reclaim thread to release space and the reclaim thread needs to
flush delalloc for the inode that got the memory mapped write and has its
range locked by the clone task.
Basically what happens is the following:
1) A clone operation locks inodes A and B, flushes delalloc for both
inodes in the respective file ranges and waits for any ordered extents
in those ranges to complete;
2) Before the clone task locks the file ranges, another task does a
memory mapped write (which does not lock the inode) for one of the
inodes of the clone operation. So now we have a dirty page in one of
the ranges used by the clone operation;
3) The clone operation locks the file ranges for inodes A and B;
4) Later, when iterating over the file extents of inode A, the clone
task attempts to start a transaction. There's not enough available
free metadata space, so the async reclaim task is started (if not
running already) and we wait for someone to wake us up on our
reservation ticket;
5) The async reclaim task is not able to release space by any other
means and decides to flush delalloc for the inode of the clone
operation;
6) The workqueue job used to flush the inode blocks when starting
delalloc for the inode, since the file range is currently locked by
the clone task;
7) But the clone task is waiting on its reservation ticket and the async
reclaim task is waiting on the flush job to complete, which can't
progress since the clone task has the file range locked. So unless
some other task is able to release space, for example an ordered
extent for some other inode completes, we have a deadlock between all
these tasks;
When this happens stack traces like the following show up in dmesg/syslog:
INFO: task kworker/u16:11:1810830 blocked for more than 120 seconds.
Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u16:11 state:D stack: 0 pid:1810830 ppid: 2 flags:0x00004000
Workqueue: btrfs-flush_delalloc btrfs_work_helper [btrfs]
Call Trace:
__schedule+0x5d1/0xcf0
schedule+0x45/0xe0
lock_extent_bits+0x1e6/0x2d0 [btrfs]
? finish_wait+0x90/0x90
btrfs_invalidatepage+0x32c/0x390 [btrfs]
? __mod_memcg_state+0x8e/0x160
__extent_writepage+0x2d4/0x400 [btrfs]
extent_write_cache_pages+0x2b2/0x500 [btrfs]
? lock_release+0x20e/0x4c0
? trace_hardirqs_on+0x1b/0xf0
extent_writepages+0x43/0x90 [btrfs]
? lock_acquire+0x1a3/0x490
do_writepages+0x43/0xe0
? __filemap_fdatawrite_range+0xa4/0x100
__filemap_fdatawrite_range+0xc5/0x100
btrfs_run_delalloc_work+0x17/0x40 [btrfs]
btrfs_work_helper+0xf1/0x600 [btrfs]
process_one_work+0x24e/0x5e0
worker_thread+0x50/0x3b0
? process_one_work+0x5e0/0x5e0
kthread+0x153/0x170
? kthread_mod_delayed_work+0xc0/0xc0
ret_from_fork+0x22/0x30
INFO: task kworker/u16:1:2426217 blocked for more than 120 seconds.
Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u16:1 state:D stack: 0 pid:2426217 ppid: 2 flags:0x00004000
Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs]
Call Trace:
__schedule+0x5d1/0xcf0
? kvm_clock_read+0x14/0x30
? wait_for_completion+0x81/0x110
schedule+0x45/0xe0
schedule_timeout+0x30c/0x580
? _raw_spin_unlock_irqrestore+0x3c/0x60
? lock_acquire+0x1a3/0x490
? try_to_wake_up+0x7a/0xa20
? lock_release+0x20e/0x4c0
? lock_acquired+0x199/0x490
? wait_for_completion+0x81/0x110
wait_for_completion+0xab/0x110
start_delalloc_inodes+0x2af/0x390 [btrfs]
btrfs_start_delalloc_roots+0x12d/0x250 [btrfs]
flush_space+0x24f/0x660 [btrfs]
btrfs_async_reclaim_metadata_space+0x1bb/0x480 [btrfs]
process_one_work+0x24e/0x5e0
worker_thread+0x20f/0x3b0
? process_one_work+0x5e0/0x5e0
kthread+0x153/0x170
? kthread_mod_delayed_work+0xc0/0xc0
ret_from_fork+0x22/0x30
(...)
several other tasks blocked on inode locks held by the clone task below
(...)
RIP: 0033:0x7f61efe73fff
Code: Unable to access opcode bytes at RIP 0x7f61efe73fd5.
RSP: 002b:00007ffc3371bbe8 EFLAGS: 00000202 ORIG_RAX: 000000000000013c
RAX: ffffffffffffffda RBX: 00007ffc3371bea0 RCX: 00007f61efe73fff
RDX: 00000000ffffff9c RSI: 0000560fbd604690 RDI: 00000000ffffff9c
RBP: 00007ffc3371beb0 R08: 0000000000000002 R09: 0000560fbd5d75f0
R10: 0000560fbd5d81f0 R11: 0000000000000202 R12: 0000000000000002
R13: 000000000000000b R14: 00007ffc3371bea0 R15: 00007ffc3371beb0
task: fdm-stress state:D stack: 0 pid:2508234 ppid:2508153 flags:0x00004000
Call Trace:
__schedule+0x5d1/0xcf0
? _raw_spin_unlock_irqrestore+0x3c/0x60
schedule+0x45/0xe0
__reserve_bytes+0x4a4/0xb10 [btrfs]
? finish_wait+0x90/0x90
btrfs_reserve_metadata_bytes+0x29/0x190 [btrfs]
btrfs_block_rsv_add+0x1f/0x50 [btrfs]
start_transaction+0x2d1/0x760 [btrfs]
btrfs_replace_file_extents+0x120/0x930 [btrfs]
? lock_release+0x20e/0x4c0
btrfs_clone+0x3e4/0x7e0 [btrfs]
? btrfs_lookup_first_ordered_extent+0x8e/0x100 [btrfs]
btrfs_clone_files+0xf6/0x150 [btrfs]
btrfs_remap_file_range+0x324/0x3d0 [btrfs]
do_clone_file_range+0xd4/0x1f0
vfs_clone_file_range+0x4d/0x230
? lock_release+0x20e/0x4c0
ioctl_file_clone+0x8f/0xc0
do_vfs_ioctl+0x342/0x750
__x64_sys_ioctl+0x62/0xb0
do_syscall_64+0x33/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xa9
"""
Fix both of these issues by excluding mmaps from happening we are doing
any sort of remap, which prevents this race completely.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
||
|
Josef Bacik
|
64708539cd |
btrfs: use btrfs_inode_lock/btrfs_inode_unlock inode lock helpers
A few places we intermix btrfs_inode_lock with a inode_unlock, and some places we just use inode_lock/inode_unlock instead of btrfs_inode_lock. None of these places are using this incorrectly, but as we adjust some of these callers it would be nice to keep everything consistent, so convert everybody to use btrfs_inode_lock/btrfs_inode_unlock. 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> |
||
Nikolay Borisov
|
bfc78479eb |
btrfs: make btrfs_replace_file_extents take btrfs_inode
Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
||
|
Linus Torvalds
|
7a7fd0de4a |
Merge branch 'kmap-conversion-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull kmap conversion updates from David Sterba:
"This contains changes regarding kmap API use and eg conversion from
kmap_atomic to kmap_local_page.
The API belongs to memory management but to save cross-tree
dependency headaches we've agreed to take it through the btrfs tree
because there are some trivial conversions possible, while the rest
will need some time and getting the easy cases out of the way would be
convenient.
The changes can be grouped:
- function exports, new helpers
- new VM_BUG_ON for additional verification; it's been discussed if
it should be VM_BUG_ON or BUG_ON, the former was chosen due to
performance reasons
- code replaced by relevant helpers"
[ This is an updated version of a request that originally came in during
the merge window, but I asked for some updates:
https://lore.kernel.org/lkml/cover.1614090658.git.dsterba@suse.com/
which is why this got merge after the merge window closed. - Linus ]
* 'kmap-conversion-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: use copy_highpage() instead of 2 kmaps()
btrfs: use memcpy_[to|from]_page() and kmap_local_page()
mm/highmem: Add VM_BUG_ON() to mem*_page() calls
mm/highmem: Introduce memcpy_page(), memmove_page(), and memset_page()
mm/highmem: Convert memcpy_[to|from]_page() to kmap_local_page()
mm/highmem: Lift memcpy_[to|from]_page to core
|
||
|
Ira Weiny
|
3590ec5899 |
btrfs: use memcpy_[to|from]_page() and kmap_local_page()
There are many places where the pattern kmap/memcpy/kunmap occurs. This pattern was lifted to the core common functions memcpy_[to|from]_page(). Use these new functions to reduce the code, eliminate direct uses of kmap, and leverage the new core functions use of kmap_local_page(). Also, there is 1 place where a kmap/memcpy is followed by an optional memset. Here we leave the kmap open coded to avoid remapping the page but use kmap_local_page() directly. Development of this patch was aided by the coccinelle script: // <smpl> // SPDX-License-Identifier: GPL-2.0-only // Find kmap/memcpy/kunmap pattern and replace with memcpy*page calls // // NOTE: Offsets and other expressions may be more complex than what the script // will automatically generate. Therefore a catchall rule is provided to find // the pattern which then must be evaluated by hand. // // Confidence: Low // Copyright: (C) 2021 Intel Corporation // URL: http://coccinelle.lip6.fr/ // Comments: // Options: // // simple memcpy version // @ memcpy_rule1 @ expression page, T, F, B, Off; identifier ptr; type VP; @@ ( -VP ptr = kmap(page); | -ptr = kmap(page); | -VP ptr = kmap_atomic(page); | -ptr = kmap_atomic(page); ) <+... ( -memcpy(ptr + Off, F, B); +memcpy_to_page(page, Off, F, B); | -memcpy(ptr, F, B); +memcpy_to_page(page, 0, F, B); | -memcpy(T, ptr + Off, B); +memcpy_from_page(T, page, Off, B); | -memcpy(T, ptr, B); +memcpy_from_page(T, page, 0, B); ) ...+> ( -kunmap(page); | -kunmap_atomic(ptr); ) // Remove any pointers left unused @ depends on memcpy_rule1 @ identifier memcpy_rule1.ptr; type VP, VP1; @@ -VP ptr; ... when != ptr; ? VP1 ptr; // // Some callers kmap without a temp pointer // @ memcpy_rule2 @ expression page, T, Off, F, B; @@ <+... ( -memcpy(kmap(page) + Off, F, B); +memcpy_to_page(page, Off, F, B); | -memcpy(kmap(page), F, B); +memcpy_to_page(page, 0, F, B); | -memcpy(T, kmap(page) + Off, B); +memcpy_from_page(T, page, Off, B); | -memcpy(T, kmap(page), B); +memcpy_from_page(T, page, 0, B); ) ...+> -kunmap(page); // No need for the ptr variable removal // // Catch all // @ memcpy_rule3 @ expression page; expression GenTo, GenFrom, GenSize; identifier ptr; type VP; @@ ( -VP ptr = kmap(page); | -ptr = kmap(page); | -VP ptr = kmap_atomic(page); | -ptr = kmap_atomic(page); ) <+... ( // // Some call sites have complex expressions within the memcpy // match a catch all to be evaluated by hand. // -memcpy(GenTo, GenFrom, GenSize); +memcpy_to_pageExtra(page, GenTo, GenFrom, GenSize); +memcpy_from_pageExtra(GenTo, page, GenFrom, GenSize); ) ...+> ( -kunmap(page); | -kunmap_atomic(ptr); ) // Remove any pointers left unused @ depends on memcpy_rule3 @ identifier memcpy_rule3.ptr; type VP, VP1; @@ -VP ptr; ... when != ptr; ? VP1 ptr; // <smpl> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
||
|
Filipe Manana
|
3660d0bcdb |
btrfs: fix stale data exposure after cloning a hole with NO_HOLES enabled
When using the NO_HOLES feature, if we clone a file range that spans only
a hole into a range that is at or beyond the current i_size of the
destination file, we end up not setting the full sync runtime flag on the
inode. As a result, if we then fsync the destination file and have a power
failure, after log replay we can end up exposing stale data instead of
having a hole for that range.
The conditions for this to happen are the following:
1) We have a file with a size of, for example, 1280K;
2) There is a written (non-prealloc) extent for the file range from 1024K
to 1280K with a length of 256K;
3) This particular file extent layout is durably persisted, so that the
existing superblock persisted on disk points to a subvolume root where
the file has that exact file extent layout and state;
4) The file is truncated to a smaller size, to an offset lower than the
start offset of its last extent, for example to 800K. The truncate sets
the full sync runtime flag on the inode;
6) Fsync the file to log it and clear the full sync runtime flag;
7) Clone a region that covers only a hole (implicit hole due to NO_HOLES)
into the file with a destination offset that starts at or beyond the
256K file extent item we had - for example to offset 1024K;
8) Since the clone operation does not find extents in the source range,
we end up in the if branch at the bottom of btrfs_clone() where we
punch a hole for the file range starting at offset 1024K by calling
btrfs_replace_file_extents(). There we end up not setting the full
sync flag on the inode, because we don't know we are being called in
a clone context (and not fallocate's punch hole operation), and
neither do we create an extent map to represent a hole because the
requested range is beyond eof;
9) A further fsync to the file will be a fast fsync, since the clone
operation did not set the full sync flag, and therefore it relies on
modified extent maps to correctly log the file layout. But since
it does not find any extent map marking the range from 1024K (the
previous eof) to the new eof, it does not log a file extent item
for that range representing the hole;
10) After a power failure no hole for the range starting at 1024K is
punched and we end up exposing stale data from the old 256K extent.
Turning this into exact steps:
$ mkfs.btrfs -f -O no-holes /dev/sdi
$ mount /dev/sdi /mnt
# Create our test file with 3 extents of 256K and a 256K hole at offset
# 256K. The file has a size of 1280K.
$ xfs_io -f -s \
-c "pwrite -S 0xab -b 256K 0 256K" \
-c "pwrite -S 0xcd -b 256K 512K 256K" \
-c "pwrite -S 0xef -b 256K 768K 256K" \
-c "pwrite -S 0x73 -b 256K 1024K 256K" \
/mnt/sdi/foobar
# Make sure it's durably persisted. We want the last committed super
# block to point to this particular file extent layout.
sync
# Now truncate our file to a smaller size, falling within a position of
# the second extent. This sets the full sync runtime flag on the inode.
# Then fsync the file to log it and clear the full sync flag from the
# inode. The third extent is no longer part of the file and therefore
# it is not logged.
$ xfs_io -c "truncate 800K" -c "fsync" /mnt/foobar
# Now do a clone operation that only clones the hole and sets back the
# file size to match the size it had before the truncate operation
# (1280K).
$ xfs_io \
-c "reflink /mnt/foobar 256K 1024K 256K" \
-c "fsync" \
/mnt/foobar
# File data before power failure:
$ od -A d -t x1 /mnt/foobar
|
||
Qu Wenruo
|
32443de338 |
btrfs: introduce btrfs_subpage for data inodes
To support subpage sector size, data also need extra info to make sure which sectors in a page are uptodate/dirty/... This patch will make pages for data inodes get btrfs_subpage structure attached, and detached when the page is freed. This patch also slightly changes the timing when set_page_extent_mapped() is called to make sure: - We have page->mapping set page->mapping->host is used to grab btrfs_fs_info, thus we can only call this function after page is mapped to an inode. One call site attaches pages to inode manually, thus we have to modify the timing of set_page_extent_mapped() a bit. - As soon as possible, before other operations Since memory allocation can fail, we have to do extra error handling. Calling set_page_extent_mapped() as soon as possible can simply the error handling for several call sites. The idea is pretty much the same as iomap_page, but with more bitmaps for btrfs specific cases. Currently the plan is to switch iomap if iomap can provide sector aligned write back (only write back dirty sectors, but not the full page, data balance require this feature). So we will stick to btrfs specific bitmap for now. Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
||
|
Filipe Manana
|
3d45f221ce |
btrfs: fix deadlock when cloning inline extent and low on free metadata space
When cloning an inline extent there are cases where we can not just copy
the inline extent from the source range to the target range (e.g. when the
target range starts at an offset greater than zero). In such cases we copy
the inline extent's data into a page of the destination inode and then
dirty that page. However, after that we will need to start a transaction
for each processed extent and, if we are ever low on available metadata
space, we may need to flush existing delalloc for all dirty inodes in an
attempt to release metadata space - if that happens we may deadlock:
* the async reclaim task queued a delalloc work to flush delalloc for
the destination inode of the clone operation;
* the task executing that delalloc work gets blocked waiting for the
range with the dirty page to be unlocked, which is currently locked
by the task doing the clone operation;
* the async reclaim task blocks waiting for the delalloc work to complete;
* the cloning task is waiting on the waitqueue of its reservation ticket
while holding the range with the dirty page locked in the inode's
io_tree;
* if metadata space is not released by some other task (like delalloc for
some other inode completing for example), the clone task waits forever
and as a consequence the delalloc work and async reclaim tasks will hang
forever as well. Releasing more space on the other hand may require
starting a transaction, which will hang as well when trying to reserve
metadata space, resulting in a deadlock between all these tasks.
When this happens, traces like the following show up in dmesg/syslog:
[87452.323003] INFO: task kworker/u16:11:1810830 blocked for more than 120 seconds.
[87452.323644] Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1
[87452.324248] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[87452.324852] task:kworker/u16:11 state:D stack: 0 pid:1810830 ppid: 2 flags:0x00004000
[87452.325520] Workqueue: btrfs-flush_delalloc btrfs_work_helper [btrfs]
[87452.326136] Call Trace:
[87452.326737] __schedule+0x5d1/0xcf0
[87452.327390] schedule+0x45/0xe0
[87452.328174] lock_extent_bits+0x1e6/0x2d0 [btrfs]
[87452.328894] ? finish_wait+0x90/0x90
[87452.329474] btrfs_invalidatepage+0x32c/0x390 [btrfs]
[87452.330133] ? __mod_memcg_state+0x8e/0x160
[87452.330738] __extent_writepage+0x2d4/0x400 [btrfs]
[87452.331405] extent_write_cache_pages+0x2b2/0x500 [btrfs]
[87452.332007] ? lock_release+0x20e/0x4c0
[87452.332557] ? trace_hardirqs_on+0x1b/0xf0
[87452.333127] extent_writepages+0x43/0x90 [btrfs]
[87452.333653] ? lock_acquire+0x1a3/0x490
[87452.334177] do_writepages+0x43/0xe0
[87452.334699] ? __filemap_fdatawrite_range+0xa4/0x100
[87452.335720] __filemap_fdatawrite_range+0xc5/0x100
[87452.336500] btrfs_run_delalloc_work+0x17/0x40 [btrfs]
[87452.337216] btrfs_work_helper+0xf1/0x600 [btrfs]
[87452.337838] process_one_work+0x24e/0x5e0
[87452.338437] worker_thread+0x50/0x3b0
[87452.339137] ? process_one_work+0x5e0/0x5e0
[87452.339884] kthread+0x153/0x170
[87452.340507] ? kthread_mod_delayed_work+0xc0/0xc0
[87452.341153] ret_from_fork+0x22/0x30
[87452.341806] INFO: task kworker/u16:1:2426217 blocked for more than 120 seconds.
[87452.342487] Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1
[87452.343274] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[87452.344049] task:kworker/u16:1 state:D stack: 0 pid:2426217 ppid: 2 flags:0x00004000
[87452.344974] Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs]
[87452.345655] Call Trace:
[87452.346305] __schedule+0x5d1/0xcf0
[87452.346947] ? kvm_clock_read+0x14/0x30
[87452.347676] ? wait_for_completion+0x81/0x110
[87452.348389] schedule+0x45/0xe0
[87452.349077] schedule_timeout+0x30c/0x580
[87452.349718] ? _raw_spin_unlock_irqrestore+0x3c/0x60
[87452.350340] ? lock_acquire+0x1a3/0x490
[87452.351006] ? try_to_wake_up+0x7a/0xa20
[87452.351541] ? lock_release+0x20e/0x4c0
[87452.352040] ? lock_acquired+0x199/0x490
[87452.352517] ? wait_for_completion+0x81/0x110
[87452.353000] wait_for_completion+0xab/0x110
[87452.353490] start_delalloc_inodes+0x2af/0x390 [btrfs]
[87452.353973] btrfs_start_delalloc_roots+0x12d/0x250 [btrfs]
[87452.354455] flush_space+0x24f/0x660 [btrfs]
[87452.355063] btrfs_async_reclaim_metadata_space+0x1bb/0x480 [btrfs]
[87452.355565] process_one_work+0x24e/0x5e0
[87452.356024] worker_thread+0x20f/0x3b0
[87452.356487] ? process_one_work+0x5e0/0x5e0
[87452.356973] kthread+0x153/0x170
[87452.357434] ? kthread_mod_delayed_work+0xc0/0xc0
[87452.357880] ret_from_fork+0x22/0x30
(...)
< stack traces of several tasks waiting for the locks of the inodes of the
clone operation >
(...)
[92867.444138] RSP: 002b:00007ffc3371bbe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000052
[92867.444624] RAX: ffffffffffffffda RBX: 00007ffc3371bea0 RCX: 00007f61efe73f97
[92867.445116] RDX: 0000000000000000 RSI: 0000560fbd5d7a40 RDI: 0000560fbd5d8960
[92867.445595] RBP: 00007ffc3371beb0 R08: 0000000000000001 R09: 0000000000000003
[92867.446070] R10: 00007ffc3371b996 R11: 0000000000000246 R12: 0000000000000000
[92867.446820] R13: 000000000000001f R14: 00007ffc3371bea0 R15: 00007ffc3371beb0
[92867.447361] task:fsstress state:D stack: 0 pid:2508238 ppid:2508153 flags:0x00004000
[92867.447920] Call Trace:
[92867.448435] __schedule+0x5d1/0xcf0
[92867.448934] ? _raw_spin_unlock_irqrestore+0x3c/0x60
[92867.449423] schedule+0x45/0xe0
[92867.449916] __reserve_bytes+0x4a4/0xb10 [btrfs]
[92867.450576] ? finish_wait+0x90/0x90
[92867.451202] btrfs_reserve_metadata_bytes+0x29/0x190 [btrfs]
[92867.451815] btrfs_block_rsv_add+0x1f/0x50 [btrfs]
[92867.452412] start_transaction+0x2d1/0x760 [btrfs]
[92867.453216] clone_copy_inline_extent+0x333/0x490 [btrfs]
[92867.453848] ? lock_release+0x20e/0x4c0
[92867.454539] ? btrfs_search_slot+0x9a7/0xc30 [btrfs]
[92867.455218] btrfs_clone+0x569/0x7e0 [btrfs]
[92867.455952] btrfs_clone_files+0xf6/0x150 [btrfs]
[92867.456588] btrfs_remap_file_range+0x324/0x3d0 [btrfs]
[92867.457213] do_clone_file_range+0xd4/0x1f0
[92867.457828] vfs_clone_file_range+0x4d/0x230
[92867.458355] ? lock_release+0x20e/0x4c0
[92867.458890] ioctl_file_clone+0x8f/0xc0
[92867.459377] do_vfs_ioctl+0x342/0x750
[92867.459913] __x64_sys_ioctl+0x62/0xb0
[92867.460377] do_syscall_64+0x33/0x80
[92867.460842] entry_SYSCALL_64_after_hwframe+0x44/0xa9
(...)
< stack traces of more tasks blocked on metadata reservation like the clone
task above, because the async reclaim task has deadlocked >
(...)
Another thing to notice is that the worker task that is deadlocked when
trying to flush the destination inode of the clone operation is at
btrfs_invalidatepage(). This is simply because the clone operation has a
destination offset greater than the i_size and we only update the i_size
of the destination file after cloning an extent (just like we do in the
buffered write path).
Since the async reclaim path uses btrfs_start_delalloc_roots() to trigger
the flushing of delalloc for all inodes that have delalloc, add a runtime
flag to an inode to signal it should not be flushed, and for inodes with
that flag set, start_delalloc_inodes() will simply skip them. When the
cloning code needs to dirty a page to copy an inline extent, set that flag
on the inode and then clear it when the clone operation finishes.
This could be sporadically triggered with test case generic/269 from
fstests, which exercises many fsstress processes running in parallel with
several dd processes filling up the entire filesystem.
CC: stable@vger.kernel.org # 5.9+
Fixes:
|
||
|
Nikolay Borisov
|
b06359a325 |
btrfs: make btrfs_cont_expand take btrfs_inode
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
||
|
Nikolay Borisov
|
9a56fcd15a |
btrfs: make btrfs_update_inode take btrfs_inode
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
||
|
Nikolay Borisov
|
76aea53796 |
btrfs: make btrfs_inode_safe_disk_i_size_write take btrfs_inode
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
||
|
Filipe Manana
|
2766ff6176 |
btrfs: update the number of bytes used by an inode atomically
There are several occasions where we do not update the inode's number of used bytes atomically, resulting in a concurrent stat(2) syscall to report a value of used blocks that does not correspond to a valid value, that is, a value that does not match neither what we had before the operation nor what we get after the operation completes. In extreme cases it can result in stat(2) reporting zero used blocks, which can cause problems for some userspace tools where they can consider a file with a non-zero size and zero used blocks as completely sparse and skip reading data, as reported/discussed a long time ago in some threads like the following: https://lists.gnu.org/archive/html/bug-tar/2016-07/msg00001.html The cases where this can happen are the following: -> Case 1 If we do a write (buffered or direct IO) against a file region for which there is already an allocated extent (or multiple extents), then we have a short time window where we can report a number of used blocks to stat(2) that does not take into account the file region being overwritten. This short time window happens when completing the ordered extent(s). This happens because when we drop the extents in the write range we decrement the inode's number of bytes and later on when we insert the new extent(s) we increment the number of bytes in the inode, resulting in a short time window where a stat(2) syscall can get an incorrect number of used blocks. If we do writes that overwrite an entire file, then we have a short time window where we report 0 used blocks to stat(2). Example reproducer: $ cat reproducer-1.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT xfs_io -f -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null expected=$(stat -c %b $MNT/foobar) # Create a process to keep calling stat(2) on the file and see if the # reported number of blocks used (disk space used) changes, it should # not because we are not increasing the file size nor punching holes. stat_loop $MNT/foobar $expected & loop_pid=$! for ((i = 0; i < 50000; i++)); do xfs_io -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null done kill $loop_pid &> /dev/null wait umount $DEV $ ./reproducer-1.sh ERROR: unexpected used blocks (got: 0 expected: 128) ERROR: unexpected used blocks (got: 0 expected: 128) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 2 If we do a buffered write against a file region that does not have any allocated extents, like a hole or beyond EOF, then during ordered extent completion we have a short time window where a concurrent stat(2) syscall can report a number of used blocks that does not correspond to the value before or after the write operation, a value that is actually larger than the value after the write completes. This happens because once we start a buffered write into an unallocated file range we increment the inode's 'new_delalloc_bytes', to make sure any stat(2) call gets a correct used blocks value before delalloc is flushed and completes. However at ordered extent completion, after we inserted the new extent, we increment the inode's number of bytes used with the size of the new extent, and only later, when clearing the range in the inode's iotree, we decrement the inode's 'new_delalloc_bytes' counter with the size of the extent. So this results in a short time window where a concurrent stat(2) syscall can report a number of used blocks that accounts for the new extent twice. Example reproducer: $ cat reproducer-2.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT touch $MNT/foobar write_size=$((64 * 1024)) for ((i = 0; i < 16384; i++)); do offset=$(($i * $write_size)) xfs_io -c "pwrite -S 0xab $offset $write_size" $MNT/foobar >/dev/null blocks_used=$(stat -c %b $MNT/foobar) # Fsync the file to trigger writeback and keep calling stat(2) on it # to see if the number of blocks used changes. stat_loop $MNT/foobar $blocks_used & loop_pid=$! xfs_io -c "fsync" $MNT/foobar kill $loop_pid &> /dev/null wait $loop_pid done umount $DEV $ ./reproducer-2.sh ERROR: unexpected used blocks (got: 265472 expected: 265344) ERROR: unexpected used blocks (got: 284032 expected: 283904) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 3 Another case where such problems happen is during other operations that replace extents in a file range with other extents. Those operations are extent cloning, deduplication and fallocate's zero range operation. The cause of the problem is similar to the first case. When we drop the extents from a range, we decrement the inode's number of bytes, and later on, after inserting the new extents we increment it. Since this is not done atomically, a concurrent stat(2) call can see and return a number of used blocks that is smaller than it should be, does not match the number of used blocks before or after the clone/deduplication/zero operation. Like for the first case, when doing a clone, deduplication or zero range operation against an entire file, we end up having a time window where we can report 0 used blocks to a stat(2) call. Example reproducer: $ cat reproducer-3.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f -m reflink=1 $DEV > /dev/null mount $DEV $MNT extent_size=$((64 * 1024)) num_extents=16384 file_size=$(($extent_size * $num_extents)) # File foo has many small extents. xfs_io -f -s -c "pwrite -S 0xab -b $extent_size 0 $file_size" $MNT/foo \ > /dev/null # File bar has much less extents and has exactly the same data as foo. xfs_io -f -c "pwrite -S 0xab 0 $file_size" $MNT/bar > /dev/null expected=$(stat -c %b $MNT/foo) # Now deduplicate bar into foo. While the deduplication is in progres, # the number of used blocks/file size reported by stat should not change xfs_io -c "dedupe $MNT/bar 0 0 $file_size" $MNT/foo > /dev/null & dedupe_pid=$! while [ -n "$(ps -p $dedupe_pid -o pid=)" ]; do used=$(stat -c %b $MNT/foo) if [ $used -ne $expected ]; then echo "Unexpected blocks used: $used (expected: $expected)" fi done umount $DEV $ ./reproducer-3.sh Unexpected blocks used: 2076800 (expected: 2097152) Unexpected blocks used: 2097024 (expected: 2097152) Unexpected blocks used: 2079872 (expected: 2097152) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. So fix this by: 1) Making btrfs_drop_extents() not decrement the VFS inode's number of bytes, and instead return the number of bytes; 2) Making any code that drops extents and adds new extents update the inode's number of bytes atomically, while holding the btrfs inode's spinlock, which is also used by the stat(2) callback to get the inode's number of bytes; 3) For ranges in the inode's iotree that are marked as 'delalloc new', corresponding to previously unallocated ranges, increment the inode's number of bytes when clearing the 'delalloc new' bit from the range, in the same critical section that decrements the inode's 'new_delalloc_bytes' counter, delimited by the btrfs inode's spinlock. An alternative would be to have btrfs_getattr() wait for any IO (ordered extents in progress) and locking the whole range (0 to (u64)-1) while it it computes the number of blocks used. But that would mean blocking stat(2), which is a very used syscall and expected to be fast, waiting for writes, clone/dedupe, fallocate, page reads, fiemap, etc. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Filipe Manana
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5893dfb98f |
btrfs: refactor btrfs_drop_extents() to make it easier to extend
There are many arguments for __btrfs_drop_extents() and its wrapper
btrfs_drop_extents(), which makes it hard to add more arguments to it and
requires changing every caller. I have added a couple myself back in 2014
commit
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Josef Bacik
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b9729ce014 |
btrfs: locking: rip out path->leave_spinning
We no longer distinguish between blocking and spinning, so rip out all this code. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Johannes Thumshirn
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6b613cc97f |
btrfs: reschedule when cloning lots of extents
We have several occurrences of a soft lockup from fstest's generic/175 testcase, which look more or less like this one: watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [xfs_io:10030] Kernel panic - not syncing: softlockup: hung tasks CPU: 0 PID: 10030 Comm: xfs_io Tainted: G L 5.9.0-rc5+ #768 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4-rebuilt.opensuse.org 04/01/2014 Call Trace: <IRQ> dump_stack+0x77/0xa0 panic+0xfa/0x2cb watchdog_timer_fn.cold+0x85/0xa5 ? lockup_detector_update_enable+0x50/0x50 __hrtimer_run_queues+0x99/0x4c0 ? recalibrate_cpu_khz+0x10/0x10 hrtimer_run_queues+0x9f/0xb0 update_process_times+0x28/0x80 tick_handle_periodic+0x1b/0x60 __sysvec_apic_timer_interrupt+0x76/0x210 asm_call_on_stack+0x12/0x20 </IRQ> sysvec_apic_timer_interrupt+0x7f/0x90 asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0010:btrfs_tree_unlock+0x91/0x1a0 [btrfs] RSP: 0018:ffffc90007123a58 EFLAGS: 00000282 RAX: ffff8881cea2fbe0 RBX: ffff8881cea2fbe0 RCX: 0000000000000000 RDX: ffff8881d23fd200 RSI: ffffffff82045220 RDI: ffff8881cea2fba0 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000032 R10: 0000160000000000 R11: 0000000000001000 R12: 0000000000001000 R13: ffff8882357fd5b0 R14: ffff88816fa76e70 R15: ffff8881cea2fad0 ? btrfs_tree_unlock+0x15b/0x1a0 [btrfs] btrfs_release_path+0x67/0x80 [btrfs] btrfs_insert_replace_extent+0x177/0x2c0 [btrfs] btrfs_replace_file_extents+0x472/0x7c0 [btrfs] btrfs_clone+0x9ba/0xbd0 [btrfs] btrfs_clone_files.isra.0+0xeb/0x140 [btrfs] ? file_update_time+0xcd/0x120 btrfs_remap_file_range+0x322/0x3b0 [btrfs] do_clone_file_range+0xb7/0x1e0 vfs_clone_file_range+0x30/0xa0 ioctl_file_clone+0x8a/0xc0 do_vfs_ioctl+0x5b2/0x6f0 __x64_sys_ioctl+0x37/0xa0 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f87977fc247 RSP: 002b:00007ffd51a2f6d8 EFLAGS: 00000206 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f87977fc247 RDX: 00007ffd51a2f710 RSI: 000000004020940d RDI: 0000000000000003 RBP: 0000000000000004 R08: 00007ffd51a79080 R09: 0000000000000000 R10: 00005621f11352f2 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 00005621f128b958 R15: 0000000080000000 Kernel Offset: disabled ---[ end Kernel panic - not syncing: softlockup: hung tasks ]--- All of these lockup reports have the call chain btrfs_clone_files() -> btrfs_clone() in common. btrfs_clone_files() calls btrfs_clone() with both source and destination extents locked and loops over the source extent to create the clones. Conditionally reschedule in the btrfs_clone() loop, to give some time back to other processes. CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Filipe Manana
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306bfec02b |
btrfs: rename btrfs_punch_hole_range() to a more generic name
The function btrfs_punch_hole_range() is now used to replace all the file extents in a given file range with an extent described in the given struct btrfs_replace_extent_info argument. This extent can either be an existing extent that is being cloned or it can be a new extent (namely a prealloc extent). When that argument is NULL it only punches a hole (drops all the existing extents) in the file range. So rename the function to btrfs_replace_file_extents(). Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Filipe Manana
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bf385648fa |
btrfs: rename struct btrfs_clone_extent_info to a more generic name
Now that we can use btrfs_clone_extent_info to convey information for a new prealloc extent as well, and not just for existing extents that are being cloned, rename it to btrfs_replace_extent_info, which reflects the fact that this is now more generic and it is used to replace all existing extents in a file range with the extent described by the structure. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Filipe Manana
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fb870f6cdd |
btrfs: remove item_size member of struct btrfs_clone_extent_info
The value of item_size of struct btrfs_clone_extent_info is always set to the size of a non-inline file extent item, and in fact the infrastructure that uses this structure (btrfs_punch_hole_range()) does not work with inline file extents at all (and it is not supposed to). So just remove that field from the structure and use directly sizeof(struct btrfs_file_extent_item) instead. Also assert that the file extent type is not inline at btrfs_insert_clone_extent(). Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Filipe Manana
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8fccebfa53 |
btrfs: fix metadata reservation for fallocate that leads to transaction aborts
When doing an fallocate(), specially a zero range operation, we assume that reserving 3 units of metadata space is enough, that at most we touch one leaf in subvolume/fs tree for removing existing file extent items and inserting a new file extent item. This assumption is generally true for most common use cases. However when we end up needing to remove file extent items from multiple leaves, we can end up failing with -ENOSPC and abort the current transaction, turning the filesystem to RO mode. When this happens a stack trace like the following is dumped in dmesg/syslog: [ 1500.620934] ------------[ cut here ]------------ [ 1500.620938] BTRFS: Transaction aborted (error -28) [ 1500.620973] WARNING: CPU: 2 PID: 30807 at fs/btrfs/inode.c:9724 __btrfs_prealloc_file_range+0x512/0x570 [btrfs] [ 1500.620974] Modules linked in: btrfs intel_rapl_msr intel_rapl_common kvm_intel (...) [ 1500.621010] CPU: 2 PID: 30807 Comm: xfs_io Tainted: G W 5.9.0-rc3-btrfs-next-67 #1 [ 1500.621012] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 1500.621023] RIP: 0010:__btrfs_prealloc_file_range+0x512/0x570 [btrfs] [ 1500.621026] Code: 8b 40 50 f0 48 (...) [ 1500.621028] RSP: 0018:ffffb05fc8803ca0 EFLAGS: 00010286 [ 1500.621030] RAX: 0000000000000000 RBX: ffff9608af276488 RCX: 0000000000000000 [ 1500.621032] RDX: 0000000000000001 RSI: 0000000000000027 RDI: 00000000ffffffff [ 1500.621033] RBP: ffffb05fc8803d90 R08: 0000000000000001 R09: 0000000000000001 [ 1500.621035] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000003200000 [ 1500.621037] R13: 00000000ffffffe4 R14: ffff9608af275fe8 R15: ffff9608af275f60 [ 1500.621039] FS: 00007fb5b2368ec0(0000) GS:ffff9608b6600000(0000) knlGS:0000000000000000 [ 1500.621041] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1500.621043] CR2: 00007fb5b2366fb8 CR3: 0000000202d38005 CR4: 00000000003706e0 [ 1500.621046] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1500.621047] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1500.621049] Call Trace: [ 1500.621076] btrfs_prealloc_file_range+0x10/0x20 [btrfs] [ 1500.621087] btrfs_fallocate+0xccd/0x1280 [btrfs] [ 1500.621108] vfs_fallocate+0x14d/0x290 [ 1500.621112] ksys_fallocate+0x3a/0x70 [ 1500.621117] __x64_sys_fallocate+0x1a/0x20 [ 1500.621120] do_syscall_64+0x33/0x80 [ 1500.621123] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 1500.621126] RIP: 0033:0x7fb5b248c477 [ 1500.621128] Code: 89 7c 24 08 (...) [ 1500.621130] RSP: 002b:00007ffc7bee9060 EFLAGS: 00000293 ORIG_RAX: 000000000000011d [ 1500.621132] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fb5b248c477 [ 1500.621134] RDX: 0000000000000000 RSI: 0000000000000010 RDI: 0000000000000003 [ 1500.621136] RBP: 0000557718faafd0 R08: 0000000000000000 R09: 0000000000000000 [ 1500.621137] R10: 0000000003200000 R11: 0000000000000293 R12: 0000000000000010 [ 1500.621139] R13: 0000557718faafb0 R14: 0000557718faa480 R15: 0000000000000003 [ 1500.621151] irq event stamp: 1026217 [ 1500.621154] hardirqs last enabled at (1026223): [<ffffffffba965570>] console_unlock+0x500/0x5c0 [ 1500.621156] hardirqs last disabled at (1026228): [<ffffffffba9654c7>] console_unlock+0x457/0x5c0 [ 1500.621159] softirqs last enabled at (1022486): [<ffffffffbb6003dc>] __do_softirq+0x3dc/0x606 [ 1500.621161] softirqs last disabled at (1022477): [<ffffffffbb4010b2>] asm_call_on_stack+0x12/0x20 [ 1500.621162] ---[ end trace 2955b08408d8b9d4 ]--- [ 1500.621167] BTRFS: error (device sdj) in __btrfs_prealloc_file_range:9724: errno=-28 No space left When we use fallocate() internally, for reserving an extent for a space cache, inode cache or relocation, we can't hit this problem since either there aren't any file extent items to remove from the subvolume tree or there is at most one. When using plain fallocate() it's very unlikely, since that would require having many file extent items representing holes for the target range and crossing multiple leafs - we attempt to increase the range (merge) of such file extent items when punching holes, so at most we end up with 2 file extent items for holes at leaf boundaries. However when using the zero range operation of fallocate() for a large range (100+ MiB for example) that's fairly easy to trigger. The following example reproducer triggers the issue: $ cat reproducer.sh #!/bin/bash umount /dev/sdj &> /dev/null mkfs.btrfs -f -n 16384 -O ^no-holes /dev/sdj > /dev/null mount /dev/sdj /mnt/sdj # Create a 100M file with many file extent items. Punch a hole every 8K # just to speedup the file creation - we could do 4K sequential writes # followed by fsync (or O_SYNC) as well, but that takes a lot of time. file_size=$((100 * 1024 * 1024)) xfs_io -f -c "pwrite -S 0xab -b 10M 0 $file_size" /mnt/sdj/foobar for ((i = 0; i < $file_size; i += 8192)); do xfs_io -c "fpunch $i 4096" /mnt/sdj/foobar done # Force a transaction commit, so the zero range operation will be forced # to COW all metadata extents it need to touch. sync xfs_io -c "fzero 0 $file_size" /mnt/sdj/foobar umount /mnt/sdj $ ./reproducer.sh wrote 104857600/104857600 bytes at offset 0 100 MiB, 10 ops; 0.0669 sec (1.458 GiB/sec and 149.3117 ops/sec) fallocate: No space left on device $ dmesg <shows the same stack trace pasted before> To fix this use the existing infrastructure that hole punching and extent cloning use for replacing a file range with another extent. This deals with doing the removal of file extent items and inserting the new one using an incremental approach, reserving more space when needed and always ensuring we don't leave an implicit hole in the range in case we need to do multiple iterations and a crash happens between iterations. A test case for fstests will follow up soon. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Nikolay Borisov
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998acfe8ff |
btrfs: make copy_inline_to_page take btrfs_inode
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Nikolay Borisov
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6fee248d2b |
btrfs: convert btrfs_inode_sectorsize to take btrfs_inode
It's counterintuitive to have a function named btrfs_inode_xxx which takes a generic inode. Also move the function to btrfs_inode.h so that it has access to the definition of struct btrfs_inode. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Filipe Manana
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3ebac17ce5 |
btrfs: reduce contention on log trees when logging checksums
The possibility of extents being shared (through clone and deduplication operations) requires special care when logging data checksums, to avoid having a log tree with different checksum items that cover ranges which overlap (which resulted in missing checksums after replaying a log tree). Such problems were fixed in the past by the following commits: commit |
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Nikolay Borisov
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e5b7231e20 |
btrfs: make btrfs_delalloc_reserve_space take btrfs_inode
All of its children take btrfs_inode so bubble up this requirement to btrfs_delalloc_reserve_space's interface and stop calling BTRFS_I internally. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Nikolay Borisov
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86d52921a2 |
btrfs: make btrfs_delalloc_release_space take btrfs_inode
It needs btrfs_inode so take it as a parameter directly. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Nikolay Borisov
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c2566f2289 |
btrfs: make btrfs_set_extent_delalloc take btrfs_inode
Preparation to make btrfs_dirty_pages take btrfs_inode as parameter. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Filipe Manana
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4fdb688c70 |
btrfs: fix lost i_size update after cloning inline extent
When not using the NO_HOLES feature we were not marking the destination's
file range as written after cloning an inline extent into it. This can
lead to a data loss if the current destination file size is smaller than
the source file's size.
Example:
$ mkfs.btrfs -f -O ^no-holes /dev/sdc
$ mount /mnt/sdc /mnt
$ echo "hello world" > /mnt/foo
$ cp --reflink=always /mnt/foo /mnt/bar
$ rm -f /mnt/foo
$ umount /mnt
$ mount /mnt/sdc /mnt
$ cat /mnt/bar
$
$ stat -c %s /mnt/bar
0
# -> the file is empty, since we deleted foo, the data lost is forever
Fix that by calling btrfs_inode_set_file_extent_range() after cloning an
inline extent.
A test case for fstests will follow soon.
Link: https://lore.kernel.org/linux-btrfs/20200404193846.GA432065@latitude/
Reported-by: Johannes Hirte <johannes.hirte@datenkhaos.de>
Fixes:
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Filipe Manana
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05a5a7621c |
Btrfs: implement full reflink support for inline extents
There are a few cases where we don't allow cloning an inline extent into the destination inode, returning -EOPNOTSUPP to user space. This was done to prevent several types of file corruption and because it's not very straightforward to deal with these cases, as they can't rely on simply copying the inline extent between leaves. Such cases require copying the inline extent's data into the respective page of the destination inode. Not supporting these cases makes it harder and more cumbersome to write applications/libraries that work on any filesystem with reflink support, since all these cases for which btrfs fails with -EOPNOTSUPP work just fine on xfs for example. These unsupported cases are also not documented anywhere and explaining which exact cases fail require a bit of too technical understanding of btrfs's internal (inline extents and when and where can they exist in a file), so it's not really user friendly. Also some test cases from fstests that use fsx, such as generic/522 for example, can sporadically fail because they trigger one of these cases, and fsx expects all operations to succeed. This change adds supports for cloning all these cases by copying the inline extent's data into the respective page of the destination inode. With this change test case btrfs/112 from fstests fails because it expects some clone operations to fail, so it will be updated. Also a new test case that exercises all these previously unsupported cases will be added to fstests. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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Filipe Manana
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a61e1e0df9 |
Btrfs: simplify inline extent handling when doing reflinks
We can not reflink parts of an inline extent, we must always reflink the
whole inline extent. We know that inline extents always start at file
offset 0 and that can never represent an amount of data larger then the
filesystem's sector size (both compressed and uncompressed). We also have
had the constraints that reflink operations must have a start offset that
is aligned to the sector size and an end offset that is also aligned or
it ends the inode's i_size, so there's no way for user space to be able
to do a reflink operation that will refer to only a part of an inline
extent.
Initially there was a bug in the inlining code that could allow compressed
inline extents that encoded more than 1 page, but that was fixed in 2008
by commit
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Filipe Manana
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6a17738100 |
Btrfs: move all reflink implementation code into its own file
The reflink code is quite large and has been living in ioctl.c since ever. It has grown over the years after many bug fixes and improvements, and since I'm planning on making some further improvements on it, it's time to get it better organized by moving into its own file, reflink.c (similar to what xfs does for example). This change only moves the code out of ioctl.c into the new file, it doesn't do any other change. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |