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git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
- preserve inode compression level when changing attributes
- fix lost wakeup when waiting for a zstd workspace
- fix bio context leaks after ordered extent processing errors
- in send, handle unexpected extents for non-regular inodes
- handle edge case in creation of reloc tree with enabled quotas
- in scrub report the exact failing offset, not the stripe base
- error handling fixes
- error code propagation in send, zoned mode and raid-stripe-tree
- restore active device pointer after seeding device addition error
- transaction abort fixups
- update Chris' email address
* tag 'for-7.3-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
MAINTAINERS: update Chris Mason's email address
btrfs: tests: do not touch page cache if root/inode allocation failed
btrfs: zstd: fix lost wakeup when waiting for a workspace
btrfs: do not force reloc root creation during qgroup_account_snapshot()
btrfs: send: fix lost error return value in will_overwrite_ref()
btrfs: abort transaction before releasing tree_log_mutex on commit failure
btrfs: zoned: propagate do_zone_finish() error in btrfs_zone_finish_endio()
btrfs: zoned: finish active block group cleanup if call_zone_finish() fails
btrfs: send: reject extents for non-regular inodes
btrfs: return proper negative error code for update_raid_extent_item()
btrfs: fix the possible bioc_list memory leak during error
btrfs: fix transaction use-after-free in raid stripe insertion
btrfs: scrub: report the failing sector's address, not the stripe base
btrfs: preserve the compression property when other inode flags change
btrfs: restore active device pointers after failed sprout
btrfs: detach failed sprout device from transaction update list
btrfs: clean up target device if block group marking fails
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There are two possible ways to leak bioc memory on
btrfs_ordered_extent::bioc_list:
- An error occurred for btrfs_insert_one_raid_extent()
Then the function btrfs_insert_raid_extent() immediately return
without freeing any bioc in the bioc_list.
- An ordered extent hit an IO error
In that case the ordered extent will have BTRFS_ORDERED_IOERR set, and
skip the call on btrfs_insert_raid_extent() completely.
Fix the problem by:
- Introduce a new helper, btrfs_cleanup_ordered_bioc_list()
Which will remove all bioc from the bioc_list, and release the bioc.
- Call the above helper for btrfs_insert_raid_extent()
So that the cleanup helper is always called no matter what.
- Call the above helper for btrfs_finish_one_ordered()
This is called just before the final release on the ordered extent.
This was reported by Sashiko when reviewing another patch.
Link: https://sashiko.dev/#/patchset/20260817021512.3010812-1-shuangpeng.kernel%40gmail.com
Fixes: 02c372e1f016 ("btrfs: add support for inserting raid stripe extents")
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs updates from David Sterba:
"This is the summer edition of btrfs changes, smaller than usual. Yet,
there are performance improvements in various areas or for specific
workloads and some notable changes like removing space cache v1 code
or mount option reduction.
User visible changes:
- free space v1 disabled by default; the v2 (free space tree) is mkfs
default since 5.15, filesystems with v1 still work but could be
slightly slower due to lack of block group caching
- mount option 'rescue=usebackuproot' requires read-only mount, it's
too risky to allow writable mount
- remove standalone mount option 'usebackuproot', deprecated in 5.9
- preserve constraints of NODATASUM and NODATACOW when chattr and
mount options may change the attributes
- remove arbitrary limitation of 4KiB for page size when allowing
block sizes smaller than page
- print messages when pinned block groups affect swap activation
Performance improvements:
- use iomap bounce buffer for direct io instead of a fall back to
buffered io; past correctness vs speed trade-offs dropped
performance to ~50% of theoretical maximum, now it's ~95%,
effectively doubled
- replace xarray with local LRU list for tracking inhibited
extent buffers, restored performance to pre-inhibition state
(relatively ~3x)
- remove unnecessary 1 jiffy delay in "non-SSD" mode with multiple
logging tasks, decrease latency, throughput increased ~5x on sample
workload
- skip hole detection during full fsync for files without holes
and lots of extents, reduce run time ~5x on sample workload
(microsecond ranges)
- reduce locking around extent readahead so it does not slow down
other tasks using an overlapping range
- enhance extent buffer allocation modes to allow NOWAIT semantics
in some cases
Notable fixes:
- write-protect folios during writeback, prevent concurrent mmap
and compress/checksumming/etc undesired interactions
- in zoned mode, handle transient overcommit full instead of going
read-only
- fix possible deadlock between defragmentation and delayed
allocation reservations
- handle remaining iputs at umount time
- fix lockdep warning between device scan locking and log mutex
- add workaround for degenerate RAID56 device count modes (2 and 3)
not supported by the parity calculation library
- restore check that subvolume is not read-only when changing ACLs
- retry reading verity data colliding with up-to-date status changes
Core:
- simplify raid56 stripe handling by using contiguous virtual
allocations
- in zoned mode, fix various metadata write issues in writeback or
unmount
- space reservation fixes
- remove unused data structure members
- more auto-freeing conversions
- error pointer values are printed using %pe format"
* tag 'for-7.3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (72 commits)
btrfs: skip hole detection during full fsync for files without holes
btrfs: add extra ASSERT()s to make sure the folio size is correct
btrfs: use GFP_NOWAIT for tree block readahead
btrfs: enable unlocked NOFAIL retry for eb allocations
btrfs: add struct btrfs_eb_prealloc
btrfs: factor init_extent_buffer from __alloc_extent_buffer
btrfs: qgroup: fix a wrong length calculation in qgroup_free_reserved_data()
btrfs: add validation for extent states
btrfs: use aligned range for locking in reflink
btrfs: use aligned range for locking in extent_fiemap()
btrfs: zoned: don't clobber the extent buffer when zeroing it out
btrfs: zoned: drop stranded dirty metadata buffers at unmount
btrfs: zoned: drop stranded dirty metadata on transaction abort
btrfs: zoned: flush active metadata block group at btree_writepages() start
btrfs: convert reflink.c to use btrfs_inode as parameters
btrfs: use simple booleans for log_commit field in struct btrfs_root
btrfs: check for exit condition after waking in wait_log_commit()
btrfs: move condition for log commit wait into wait_log_commit()
btrfs: remove log batch counter use for fsync
btrfs: stop sleeping for one jiffy in non-ssd mounts during log commit
...
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull misc vfs updates from Christian Brauner:
"Bigger cleanups:
- The lockref dead-count handling is tidied up.
The open-coded check for a count below zero as the dead marker
relies on information the caller should not have.
- make put_mnt_ns() leave mounts connected. Destroying a mount
namespace disconnected its mounts from their mount points. So a
file descriptor still open on the parent of a mount point could be
used to peek under it.
Locked mounts were already kept connected to prevent exactly that.
But a mount is only locked when its tree is copied across a user
namespace boundary. So a mount namespace set up by a privileged
component had no locked mounts and its mounts were disconnected.
Passing UMOUNT_CONNECTED keeps every mount connected and prevents
that bug.
- vfs_prepare_mode() passes S_IFDIR for directories. I meant to fix
that ago but didn't get to it. So now someone finally did it.
This kills the exception where the mode could be 0 when a directory
was created whereas every other creation operation passed it
explicitly already.
- move long delayed work for ufs, jffs2, hfsplus, hfs and affs from
the per-cpu system_long_wq to the new unbound system_dfl_long_wq.
None of that work relies on per-cpu state and the work item is
enqueued with queue_delayed_work() whose timer is global anyway. So
it may as well benefit from scheduler task placement.
Smaller fixes and cleanups:
- unlock_buffer() and journal_end_buffer_io_sync() use
clear_and_wake_up_bit()
- the pipe page pools are unified into a single per-pipe pool and the
extra wake_up(rd_wait) is limited to EPOLLET consumers
- eventpoll now computes its timer slack lazily in ep_poll()
- shrink_dcache_for_umount() keeps making progress on busy roots
- excess xarray nodes are freed in clear_inode()
- romfs detects hard link cycles
- the user path of nested backing files is fixed
- pidfd holds exec_update_lock around the namespace ioctl
- non-memcg-aware nr_cached_objects is skipped during memcg slab
shrink
- iomap_write_iter() always returns status
- mangle_path() is renamed to seq_mangle_path()
- inode timestamp accessors are annotated
- new regression test for pipe->poll_usage.
- a few documentation, kernel-doc and selftest fixes"
* tag 'vfs-7.3-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (67 commits)
selftests/namespaces: Fix racy pipe handshake in timens and pidns_separate
selftests/epoll: add a regression test for pipe->poll_usage
pipe: only enable the extra wake_up(rd_wait) for EPOLLET consumers
pidfd: hold exec_update_lock around namespace ioctl
fs: fix user path of nested backing files
fs: remove stale inode_insert5() kernel-doc parameter
fs: fix switch/case indentation in sysfs() syscall
fs: document semantics of kstat::{uid,gid} fields
dcache: keep shrink_dcache_for_umount() making progress on busy roots
seq_file: rename mangle_path to seq_mangle_path
nstree: add/fix struct ns_id_req kernel-doc member fields
dcache: use lockref routines for dead count checks
lockref: tidy up dead count handling
initramfs: fix typo in reserve_initrd_mem comment
fs/pipe: unify the page pools into a single per-pipe pool
fs: annotate inode timestamp accessors
eventpoll: compute timer slack lazily in ep_poll()
selftests/filesystems: add mntns cleanup test
put_mnt_ns(): leave mounts connected
affs: Move long delayed work on system_dfl_long_wq
...
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs lookup updates from Christian Brauner:
"This refactors lookup_open() and adds vfs_lookup_open() for nfsd.
mnt_want_write() and parent locking are moved into lookup_open()
itself.
audit_inode_child() is also now called in lookup_open() on failure.
That is the calling convention in vfs_create() and vfs_mkdir(), but
lookup_open() made no such call when atomic_open() should have created
a file and did not. And neither did the regular ->create() path fwiw.
This also contains work to remove the unneeded excl argument from the
->create() inode op"
* tag 'vfs-7.3-rc1.lookup' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
fs/namei.c: fix coding style in atomic_open() and lookup_open()
fs/namei.c: fix kerneldoc of atomic_open() and vfs_lookup_open()
fs/namei.c: update stale comments in lookup_open()
Remove excl arg to ->create inode_operation
fs/namei.c: update kerneldoc of atomic_open()
vfs: call audit_inode_child() in lookup_open() on failure
vfs: move create error && negative dentry case in lookup_open() up
VFS: add vfs_lookup_open() for nfsd
VFS: move delegated_inode retry loop into lookup_open()
VFS: move mnt_want_write() and locking into lookup_open()
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During an interrupted mount, I got the following messages:
workqueue: Failed to create a rescuer kthread for wq "btrfs-qgroup-rescan": -EINTR
BTRFS error (device dm-3): open_ctree failed: -12
Workqueue code is outputting a human readable error string, meanwhile
we're still using a numeric error code.
So follow the workqueue code to use "%pe" format, which will
automatically convert an error pointer to the human readable string.
However this is a minor pitfall, if the return value is not an error
code, e.g. a positive number, "%pe" with "ERR_PTR(ret)" will output the
pointer as a hash value, e.g.:
ret=1 %pe out=0000000019414716
ret=-22 %pe out=-EINVAL
So we should not use this "%pe" output for callsites that are known to
return positive values.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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commit 095be159f3eb ("btrfs: unify folio dirty flag clearing") replaced
the folio_clear_dirty_for_io() call in extent_write_cache_pages() with a
plain folio_test_dirty() check. Besides clearing the dirty flag,
folio_clear_dirty_for_io() also calls folio_mkclean(), which write-protects
the shared mmap PTEs mapping the folio. Note that we still do call
folio_clear_dirty_for_io() later in submit_one_sector() when we clear
dirty on the last sector of the folio (the only sector for non-subpage
cases). But we lost this early call in extent_write_cache_pages().
Without the extra write-protection, a process with the file mmap-ed can
modify a sector while it is being used by writeback in a way that
expects a stable folio (checksumming, compressing, copying, etc...)
without faulting, which manifests as a handful of concrete bugs.
1. For large folios or subpage sectorsize, it is possible to submit a bio
which does not cover the whole folio. When this happens, we will have a
bio in flight for a folio that we have *not* called
folio_clear_dirty_for_io() on. If a task with an existing mmap-ed PTE
writes (without faulting..) in this window, it can result in
corruptions. If the write arrives while the checksumming or writing itself
is underway, this can result in an invalid checksum and later corruption
reports on read. If the write arrives after checksumming/writing is done
but before the last sector dirty is cleared, then the write is present
in page cache but doesn't affect the dirty tracking and will be lost
when the folio is fully finished being submitted and the dirty bit
is cleared. This results in losing the write even if fsync() is called.
2. For zoned submissions which are done in batch separate from the main
extent_writepage() loop, we also risk csum violations for those
submissions. Zoned writes are clamped to max_zone_append_size and are
not aligned with folios, so a submission can span two folios. The first
folio being processed in extent_write_cache_pages() will call
extent_write_locked_range() which will submit the partial range of the
next folio, while the rest of that folio could still be dirty. So
clearing dirty on the submitted sectors doesn't call
folio_clear_dirty_for_io() and we have the same issue. Since
extent_write_cache_pages() skips these batch submitted folios (they are
already marked for writeback from submission by the preceding folio), we
must add the extra write protection in lock_delalloc_folios().
3. For inline extents this will subtly risk losing writes that happen
after/while we copy the inline extent but before we clear dirty on
the folio.
4. For folios spanning EOF, mmap could tamper with the zeroed bytes past
EOF and cause them to be persisted where future faults would improperly
see them instead of zeros.
5. Finally, for compressed extents, we risk modifying the folios while we
work on compressing them which will result in corrupted compressed data.
Specifically, in run_delalloc_compressed() we queue up work to do
compress_file_range() in BTRFS_COMPRESSION_CHUNK_SIZE (512K) chunks which
will call btrfs_folio_clamp_clear_dirty() on the range. For non-subpage,
this will always clear the whole folio, safely. For subpage, we risk a
partial clear here as well. In particular, imagine a 2M folio broken up
into 512K chunks of work which might start compression work on one chunk
before all the chunks compress_file_range() workers have gotten far
enough to finish clearing all the dirty bitmaps of the folio and getting
to folio_clear_dirty_for_io(). Large folios on the edges of submission
ranges are similarly at risk to be only partly cleared.
This particular gap was introduced by a second patch in the same series:
commit a4ef54dbb576 ("btrfs: make extent_range_clear_dirty_for_io() to handle sector size < page size cases")
We cannot simply restore the call to folio_clear_dirty_for_io() because
that also drops the dirty flag off the folio which violates invariants
introduced for large folios by
commit 334509ce9d07 ("btrfs: use dirty flag to check if an ordered extent needs to be truncated")
and results in failing to invalidate clean folios past i_size, resulting
in deadlocks.
Therefore, to fix it, leave the existing semantics w.r.t. the folio's
dirty flag (to preserve the correct invalidate behavior) but ensure that
the other aspect of folio_clear_dirty_for_io(), folio_mkclean(), is run
on the folio when we lock it for writeback.
Finally, to help prevent similar regressions in the future, add a debug
warning that triggers at the known corruption sites if we have failed to
write protect the folio.
Assisted-by: LLM (debug, reproduce, research fix, review patch)
Fixes: 095be159f3eb ("btrfs: unify folio dirty flag clearing")
Fixes: a4ef54dbb576 ("btrfs: make extent_range_clear_dirty_for_io() to handle sector size < page size cases")
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
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The nodesize and sectorsize are all u32 values, there is no need to use
u64 for local usage.
Furthermore some call sites also use "blocksize" or "bs" for sectorsize,
also change them to use the minimal type u32 instead.
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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A swap file on btrfs will pin down block groups that cover the swap file
extent.
Pinned down block groups will be skipped for scrub and relocation.
These degradation on critical btrfs maintenance operations is never
properly educated to end users, and have already caused problems
including:
- Scrub finished too quick
Because the enabled swap file has pinned down most of the block
groups. Thus any file extents in those block groups, even not utilized
by the swap file, will be skipped from scrub.
- Unbalanced data and metadata usage, meanwhile relocation won't help
The same reason, pinned down block groups will not be considered as
relocation target, thus data extents that are not utilized by the swap
file can still be skipped from relocation.
Although we already have kernel messages for both scrub and balance, the
balance one is still info level.
To better communicate those potential long term problems, add the
following output into dmesg:
- Change the message level to warn for __btrfs_balance()
- Total pinned down block group number and size during swapfile activation
- Total released block group number and size during swapfile deactivation
The above messages have info level.
- The fact that pinned down block groups will not be scrubbed nor
balanced
The above message has warning level.
The example output would look like the following, for enabling a 1.2G
swapfile, which pinned down 2G block groups:
BTRFS info (device dm-3): swapfile activated on root 5 ino 257, pinned down 2147483648 bytes from 2 block group(s)
BTRFS warning (device dm-3): block groups with swapfile extents will not be scrubbed or balanced
Adding 1257468k swap on /mnt/btrfs/foobar. Priority:-1 extents:1 across:1257468k
BTRFS info (device dm-3): swapfile deactivated on root 5 ino 257, released 2147483648 bytes from 2 block group(s)
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull Btrfs Fixes 2: Electric Boogaloo from David Sterba:
"This brings back the fixup worker infrastructure.
It's a mechanism to detect pages/folios that are marked dirty without
filesystem knowledge and require COW fixup. The consequence of not
doing so is silent data loss.
The first patch covers the scenarios in detail, also reflecting folio
API port and subpage block size support added in recent years. The
original fixup worker was only for pages.
The patch is relatively big, half of the code is debugging and support
code, the rest is the core design around the detection and fix.
The second patch handles an unlikely case when there's work left
during unmount"
* tag 'for-7.2-rc6-fixup-worker-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: flush the fixup workers during close_ctree
btrfs: trigger cow fixup via dirty_folio()
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git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
- fix leak in encoded ioctl write
- disable large folios on systems with highmem
- disable block size > page size when there's no transparent hugepage
support (under experimental config)
- reject compressed inline extents without valid LZO headers
- properly initialize cached inode mapping (if block size > page size)
* tag 'for-7.2-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: initialize inode mapping flags for cached inodes
btrfs: disable bs > ps support if no transparent hugepage support
btrfs: fix memory leak in btrfs_do_encoded_write()
btrfs: lzo: reject inline extents without valid headers
btrfs: disable large folios for systems with highmem
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Reintroducing the COW fixup worker brought back the unmount race fixed
by commit 41fd1e94066a ("btrfs: wait for fixup workers before stopping
cleaner kthread during umount") without bringing back the fix.
A fixup work item queued by the final writeback pass can still be in flight
when close_ctree() stops the cleaner kthread and frees the fs roots.
While destroy_workqueue() drains the queue, that happens after the
cleaner thread was freed, so btrfs_add_delayed_iput() called from the
fixup worker is no longer safe (not to mention that we are already in
BTRFS_FS_STATE_NO_DELAYED_IPUT when it runs).
Therefore we need to bring back explicitly flushing the fixup workqueue
as in Filipe's original fix. The first flush will catch all the fixup
writeback queued during the final sync before umount, but some of that
might hit memory allocation errors and stay fixup in the blocks/folio,
leading any subsequent writeback triggered *inside* umount (e.g. reclaim
workers shutting down) to hit it and queue again. To fix that, and the
possibility of any really long-lived pinned folios getting marked, deny
queueing new fixup during umount. That allows us to flush twice (once
before doing a real writeback pass to get the actual data, second time
to clean up any rather unlikely stragglers right before declaring
BTRFS_FS_STATE_NO_DELAYED_IPUT) and be certain nothing got re-queued.
Reproduced by injecting a one-shot 30s sleep at the head of
btrfs_writepage_fixup_worker() on a KASAN kernel, running the normal
reproducing read dio workload before unmount and then observing:
BUG: KASAN: slab-use-after-free in _raw_spin_lock_irqsave+0x35/0x50
Read of size 1 at addr ffff88810b4b08f8 by task kworker/u32:5/219
Workqueue: btrfs-fixup btrfs_writepage_fixup_worker [btrfs]
Call Trace:
_raw_spin_lock_irqsave+0x35/0x50
try_to_wake_up+0xc0/0x18c0
btrfs_writepage_fixup_worker+0x7f3/0xf20 [btrfs]
...
Fixes: 4be9c7da6860 ("btrfs: trigger cow fixup via dirty_folio()")
Assisted-by: LLM (reproduction, analysis)
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
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[BUG]
When running generic/795 with 8K block size, 4K page size, the test
always fails, triggering some ASSERT()s related to folio size:
795 (241074): drop_caches: 3
assertion failed: IS_ALIGNED(start, blocksize) && IS_ALIGNED(end + 1, blocksize), in extent_io.c:1404 (blocksize=8192 root=262 ino=258 start=16826368 end=16830463 mapping min order=0)
------------[ cut here ]------------
kernel BUG at extent_io.c:1404!
Oops: invalid opcode: 0000 [#1] SMP
CPU: 8 UID: 0 PID: 241105 Comm: fsstress Tainted: G OE 7.2.0-rc5-custom+ #442 PREEMPT(full) f4bfb352566f3949f29c233ce6f735050a03b245
Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 02/02/2022
RIP: 0010:assert_folio_range.cold+0x3d/0x3f [btrfs]
Call Trace:
<TASK>
btrfs_read_folio+0x9e/0x170 [btrfs 4cd1dd93b341b8ef766643f9512f4a86259567a3]
prepare_one_folio.constprop.0+0x104/0x2a0 [btrfs 4cd1dd93b341b8ef766643f9512f4a86259567a3]
btrfs_buffered_write+0x285/0xa50 [btrfs 4cd1dd93b341b8ef766643f9512f4a86259567a3]
btrfs_do_write_iter+0x1aa/0x210 [btrfs 4cd1dd93b341b8ef766643f9512f4a86259567a3]
iter_file_splice_write+0x31a/0x540
direct_splice_actor+0x53/0x170
splice_direct_to_actor+0xe9/0x240
do_splice_direct+0x76/0xb0
vfs_copy_file_range+0x1fd/0x630
__x64_sys_copy_file_range+0xf9/0x220
do_syscall_64+0xe1/0x790
entry_SYSCALL_64_after_hwframe+0x4b/0x53
</TASK>
---[ end trace 0000000000000000 ]---
The ASSERT() itself is added by a later patch.
The crash is triggered with that new debug patch, and without this fix.
[CAUSE]
In the above case, the start 16826368 is properly 8K aligned, but the
end (16830463 + 1) is not 8K aligned.
Furthermore the mapping's minimal folio order is 0, not the expected 1
for 8K block size with 4K page size.
So this means some inodes do not have btrfs_set_inode_mapping_order()
called on it.
The missing btrfs_set_inode_mapping_order() call happens for cached
inodes, through the following events:
- btrfs_create_new_inode() called for inode X
Which properly sets minimal folio order for the VFS inode.
- btrfs_update_inode() called for inode X
Which calls btrfs_delayed_update_inode() to create a delayed_node
into root->delayed_nodes xarray.
- Drop cache/memory pressure, evicting in-memory inode X
Which evicted the inode X, but delayed_node is still in
root->delayed_nodes for future reuse.
- btrfs_iget() for inode X called again
btrfs_iget()
|- btrfs_iget_locked()
| |- iget5_locked_rcu()
| Which creates a new vfs_inode for btrfs, whose mapping still
| has the minimal order as 0.
|
|- btrfs_read_locked_inode()
|- btrfs_fill_inode()
| |- btrfs_get_delayed_node()
| Which found out the previous node, and use that delayed
| node to initialize the new inode.
|
|- filled = true;
|- if (filled) goto cache_index;
Which skips the btrfs_update_inode_mapping_flags() and
btrfs_set_inode_mapping_order() calls.
So the inode still has minimal folio order set as 0, not
the required 1.
Thus later page cache read will get a folio whose size is smaller than
block size, as the mapping has its minimal folio order set as 0 not 1,
then trigger the ASSERT().
[FIX]
Move the btrfs_update_inode_mapping_flags() and
btrfs_set_inode_mapping_order() calls under cache_index label,
so that the mapping flags and minimal folio order is always set
no matter if we have a cached inode.
Assisted-by: LLM (analysis)
Fixes: ecde48a1a6b3 ("btrfs: expose per-inode stable writes flag")
Fixes: cc38d178ff33 ("btrfs: enable large data folio support under CONFIG_BTRFS_EXPERIMENTAL")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Local fuzzing of 6.12.94 has found the following memory leak:
Unreferenced object 0xffff888018050a80 (size 64):
comm "syz.0.17", pid 10297, jiffies 4294953601
hex dump (first 32 bytes):
00 10 00 00 00 00 00 00 01 00 00 00 00 00 00 00 ................
10 0a 05 18 80 88 ff ff 10 0a 05 18 80 88 ff ff ................
backtrace (crc a8a6fc29):
kmemleak_alloc_recursive include/linux/kmemleak.h:42 [inline]
slab_post_alloc_hook mm/slub.c:4152 [inline]
slab_alloc_node mm/slub.c:4197 [inline]
__kmalloc_cache_noprof+0x168/0x2c0 mm/slub.c:4358
kmalloc_noprof include/linux/slab.h:878 [inline]
extent_changeset_alloc fs/btrfs/extent_io.h:207 [inline]
qgroup_reserve_data+0x1c5/0x7d0 fs/btrfs/qgroup.c:4305
btrfs_qgroup_reserve_data+0x2e/0xb0 fs/btrfs/qgroup.c:4355
btrfs_do_encoded_write+0x92e/0x1040 fs/btrfs/inode.c:9746
btrfs_encoded_write fs/btrfs/file.c:1482 [inline]
btrfs_do_write_iter+0x280/0x610 fs/btrfs/file.c:1507
btrfs_ioctl_encoded_write+0x3d6/0x490 fs/btrfs/ioctl.c:4738
btrfs_ioctl+0x6f9/0xc90 fs/btrfs/ioctl.c:-1
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl+0xf9/0x170 fs/ioctl.c:892
do_syscall_x64 arch/x86/entry/common.c:47 [inline]
do_syscall_64+0xbe/0x1a0 arch/x86/entry/common.c:78
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Unreferenced object 0xffff888018050a00 (size 64):
comm "syz.0.17", pid 10297, jiffies 4294953601
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 ff 0f 00 00 00 00 00 00 ................
90 0a 05 18 80 88 ff ff 90 0a 05 18 80 88 ff ff ................
backtrace (crc cb5c9580):
kmemleak_alloc_recursive include/linux/kmemleak.h:42 [inline]
slab_post_alloc_hook mm/slub.c:4152 [inline]
slab_alloc_node mm/slub.c:4197 [inline]
__kmalloc_cache_noprof+0x168/0x2c0 mm/slub.c:4358
kmalloc_noprof include/linux/slab.h:878 [inline]
kzalloc_noprof include/linux/slab.h:1014 [inline]
ulist_prealloc+0x9c/0x110 fs/btrfs/ulist.c:114
extent_changeset_prealloc fs/btrfs/extent_io.h:217 [inline]
__set_extent_bit+0x16b/0x1a70 fs/btrfs/extent-io-tree.c:1086
set_record_extent_bits+0x50/0x90 fs/btrfs/extent-io-tree.c:1821
qgroup_reserve_data+0x274/0x7d0 fs/btrfs/qgroup.c:4312
btrfs_qgroup_reserve_data+0x2e/0xb0 fs/btrfs/qgroup.c:4355
btrfs_do_encoded_write+0x92e/0x1040 fs/btrfs/inode.c:9746
btrfs_encoded_write fs/btrfs/file.c:1482 [inline]
btrfs_do_write_iter+0x280/0x610 fs/btrfs/file.c:1507
btrfs_ioctl_encoded_write+0x3d6/0x490 fs/btrfs/ioctl.c:4738
btrfs_ioctl+0x6f9/0xc90 fs/btrfs/ioctl.c:-1
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl+0xf9/0x170 fs/ioctl.c:892
do_syscall_x64 arch/x86/entry/common.c:47 [inline]
do_syscall_64+0xbe/0x1a0 arch/x86/entry/common.c:78
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Fix this by freeing an extent changeset before returning from
btrfs_do_encoded_write().
Fixes: 7c0c7269f7b5 ("btrfs: add BTRFS_IOC_ENCODED_WRITE")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
The only time that 'false' is passed as the 'excl' arg to the ->create
inode_operation is in lookup_open() when ->atomic_open is not provided
by the parent directory.
*all* directory inode_operations which do not have ->atomic_open
completely ignore the 'excl' arg.
Therefore we don't need the 'excl' arg. Those few ->create operations
which pay attention to the arg are only ever called with a value of
'true'.
We remove that arg and change all ->create operations to behave as those
thhe arg were 'true'.
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://patch.msgid.link/178290671516.27465.15984496764174914338@noble.neil.brown.name
Reviewed-by: Jori Koolstra <jkoolstra@xs4all.nl>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
|
|
The problem scenario:
If we have a folio mmapped shared and then somebody does a dio read with
that folio as the read destination, then it is possible that the dio
will see a dirty destination page when it starts (and thus skip
dirtying and just GUP pin it) but then while it is doing the read, btrfs
finishes writing it back and by the endio, the folio is clean. In that
case, the dio read must re-dirty the folio with aops->dirty_folio():
btrfs_check_read_bio()
|- __iomap_dio_bio_end_io() from btrfs_bio_end_io()
|- bio_check_pages_dirty()
|- bio_dirty_fn()
|- bio_release_pages(bio, true)
|- __bio_release_pages(bio, mark_dirty == true)
|- folio_lock()
|- folio_mark_dirty()
|- aops->dirty_folio()
|- folio_unlock()
A data block normally moves through writeback as follows:
TASK
folio_lock
write clean -> dirty bit + delalloc
folio_unlock
WRITEBACK
for-each-dirty-folio:
folio_lock
run_delalloc delalloc consumed -> dirty bit + OE
submission dirty bit consumed -> writeback bit + OE
folio_unlock
ENDIO
endio OE bytes accounted
OE finish writeback -> clean; destroy OE
Three critical invariants that this path maintains are:
I1. Any dirty block is covered by delalloc xor an ordered extent
I2. Any dirty block covered by an OE will be submitted into that OE
I3. Any dirty block already submitted into an OE will not be submitted
again into the same OE.
These ensure that the block will be written exactly once. It is clear
that not reserving delalloc for the re-dirty case violates I1.
This situation, even without bs < folio_size, has long required btrfs to
fixup such dirty pages during writeback with an asynchronous worker that
is allowed to do this expensive work and writeback does not proceed for
a folio while it is doing this work.
Commit 247e743cbe6e ("Btrfs: Use async helpers to deal with pages that
have been improperly dirtied") introduced the COW fixup to catch exactly
this class at writeback, way back in 2008.
Since then, there have been many advances to prevent most of the causes
of such re-dirtying and we thought we could get away with removing the
annoying cow-fixup in the hope of simplifying writeback for large folio
support.
Commit b2a9f217ad3f ("btrfs: remove the COW fixup mechanism")
Commit 4927b141877c ("btrfs: remove folio ordered flag and subpage bitmap")
Since it turns out this assumption was incorrect, as evidenced by the
report and attendant reproducers, we must reintroduce the fixup concept.
This is of course critically further complicated by bs < folio_size. In
that case, rather than just a folio dirty bit, we have a bitmap for the
dirty blocks in the folio. And the (also broken) invariant is:
I4. folio dirty IFF at least one block bitmap dirty.
The original report of a stall on a misinterpreted empty bitmap is
exactly evidence of a violation of I4.
It is exactly because of bs < folio_size we don't want to simply revert the
removal patches. The original fixup was not properly bs < folio_size
aware, which motivated removal in the first place. So we wish to build a
bs < folio_size aware fixup.
One other important detail from the old design, any normal write that
happens after a re-dirty but before a fixup is racing with the cow fixup
to do the delalloc reservation, therefore it must cancel the fixup state.
If it arrives after the reservation exists, it will be a normal dirty
overwrite. This critically informs the design in a pretty clear way.
fixup requiring re-dirty has folio granularity, while cancellation has
delalloc (block) granularity so while we only ever produce fixup in
chunks of folios, we must be able to clear it in blocks. Therefore we
must track the blocks needing fixup at block granularity.
The obvious way to do this is with a new bitmap in btrfs_folio_state,
but it is desirable to avoid that if possible. Unfortunately, I don't
think it is possible and the reason is subtle and leans on a sort of
extreme reproducer, but I think can be explained relatively succinctly.
Consider a folio whose two halves will land in different ordered extents
(can be accomplished with tricks using nodatasum) and a dio read is
running with it as the shared mmap destination.
1. The front half:
a. folio comes clean on a normal write
b. dio read completes into the folio marking it fixup.
c. a write comes for the previous folio for a range extending into
this folio, this is a cancellation of the fixup which reserves
space.
d. writeback runs on the range *not* overlapping the folio. This half
remains dirty but is now covered by an OE and is awaiting
writeback running on its range to be submitted and finish the OE.
2. The back half:
a. the folio is part of an OE that gets far enough along to clear
writeback.
b. dio read completes into the folio marking it fixup.
After this, the folio's front half is dirty in the "normal" sense, it
needs to be submitted to the OE waiting for it. It's a cancelled fixup.
Meanwhile, the second half is a true fresh fixup. So at this point if we
run writeback on this folio, we genuinely can't know what to do without
block level information. If we submit it, we submit unreserved dirty
from the back half. If we don't, we will never finish the OE waiting for
it. So it's either a corruption or a deadlock.
Thus, the full high level design picture:
- btrfs_data_dirty_folio(): For out of band non-reserving dirties,
mark still-clean blocks inside EOF dirty and set their fixup bits
(the event carries no range, so every clean block is suspect).
Already-dirty blocks are covered or pending and are left alone.
- Writeback: skip fixup blocks and enqueue work for them
- writepage_fixup(): for each fixup block do the fixup reservation in a
worker, after which the blocks can be written back normally.
- Typical reserving write paths cancel fixup state for the ranges they
cover with btrfs_folio_cancel_fixup()
Link: https://lore.kernel.org/linux-btrfs/20260721191152.101118-1-borntraeger@linux.ibm.com/
Assisted-by: LLM
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"I'm catching up with the fix backlog in the development branch, so
here's a number of them and will probably send one more for this or
the next rc:
- relocation fixes:
- skip attempting compression on reloc inodes
- exclude inline extents from file extent offset checks
- fix minor memory leak after error when adding reloc root
- fix root cleanup after inserting and merging
- fix clearing folio tags after writeback
- clear logging flag of extent map before splitting
- fix unsigned 32/64 type conversions when accounting dirty metadata,
leading to continually exceeding threshold
- fix regression in 32bit compat ioctl for subvolume info
- fix type of SEARCH_TREE ioctl buffer in UAPI header
- fix expression in ASSERT expression which can be unconditionally
evaluated on some compilers
- only account delalloc bytes for regular inodes"
* tag 'for-7.2-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: fix GET_SUBVOL_INFO after compat refactor
btrfs: free mapping node on duplicate reloc root insert
btrfs: fix a regression where PAGECACHE_TAG_DIRTY is never cleared
btrfs: don't propagate EXTENT_FLAG_LOGGING to split extent maps
btrfs: fix u32 to s64 type conversion in dirty_metadata_bytes accounting
btrfs: fix NULL pointer deref during assertion in btrfs_backref_free_node()
btrfs: only account delalloc bytes for regular file inodes in btrfs_getattr()
btrfs: reject inline file extents item in get_new_location()
btrfs: do not try compression for data reloc inodes
btrfs: declare btrfs_ioctl_search_args_v2::buf as __u8
btrfs: fix reloc root cleanup in merge_reloc_roots()
btrfs: fix use-after-free on reloc root after error in insert_dirty_subvol()
|
|
btrfs_getattr() unconditionally reads BTRFS_I(inode)->new_delalloc_bytes
and adds it (sector-aligned) to stat->blocks for every inode type.
However, new_delalloc_bytes lives in a union with last_dir_index_offset:
union {
u64 new_delalloc_bytes; /* files only */
u64 last_dir_index_offset; /* directories only */
};
For a directory inode this memory holds last_dir_index_offset, which is
set during directory logging (e.g. flush_dir_items_batch()) to the
offset of the last logged BTRFS_DIR_INDEX_KEY. That offset grows with
the number of entries ever created in the directory (dir indexes are
monotonic and never reused), so it can be arbitrarily large.
As a result, after a directory has been logged (e.g. via an fsync that
triggers directory logging), btrfs_getattr() reports inflated st_blocks
for that directory. The inflation is purely in-core and disappears
after the inode is evicted and reloaded (btrfs_alloc_inode() zeroes the
union), e.g. after a remount.
Reproducer (on a btrfs filesystem):
D=/mnt/btrfs/d
mkdir -p $D
for i in $(seq 1 20000); do touch $D/f$i; done
sync # commit, push dir index high
touch $D/trigger # dirty the dir in a new transaction
xfs_io -c fsync $D # log the directory -> sets last_dir_index_offset
stat -c '%b' $D # st_blocks is now inflated (e.g. 40)
# umount + mount -> st_blocks drops back to the correct value
The evict path already knows this union is type-dependent and guards the
corresponding WARN_ON with !S_ISDIR() in btrfs_destroy_inode(); only
btrfs_getattr() was missing the equivalent check.
Only read new_delalloc_bytes for regular files, which are the only
inodes that ever set it.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Dave Chen <davechen@synology.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
vfs_mkdir() now sets the S_IFDIR type bit in the mode it passes to
->mkdir(), so OR-ing S_IFDIR into the mode again in btrfs_mkdir() is
redundant. Drop it.
Assisted-by: LLM
Signed-off-by: Jori Koolstra <jkoolstra@xs4all.nl>
Link: https://patch.msgid.link/20260630105400.68459-7-jkoolstra@xs4all.nl
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs updates from David Sterba:
"The most noticeable change is to enable large folios by default, it's
been in testing for a few releases. Related to that is huge folio
support (still under experimental config). Otherwise a few ioctl
updates, performance improvements and usual fixes and core changes.
User visible changes:
- enable large folios by default, added in 6.17 (under experimental
build), no feature limitations, a big change internally
- new ioctl to return raw checksums to userspace (a bit tricky given
compression and tail extents), can be used for mkfs and
deduplication optimizations
- provide stable UUID for e.g. overlayfs and temp_fsid, also
reflected in statvfs() field f_fsid, internal dev_t is hashed in to
allow cloning
- add 32bit compat version of GET_SUBVOL_INFO ioctl
- in experimental build, support huge folios (up to 2M)
Performance related improvements/changes:
- limit bio size to the estimated optimum derived from the queue,
this prevents build up of too much data for writeback, which could
cause latency spikes (reported improvement 15% on sequential
writes)
- don't force direct IO to be serialized, forgotten change during
mount API port, brings back +60% of throughput
- lockless calculation of number of shrinkable extent maps, improve
performance with many memcg allocated objects
Notable fixes:
- in zoned mode, fix a deadlock due to zone reclaim and relocation
when space needs to be flushed
- don't trim device which is internally not tracked as writeable
(e.g. when missing device is being rescanned)
- fix deadlock when cloning inline extent and mounted with
flushoncommit
- fix false IO failures after direct IO falls back to buffered write
in some cases
Core:
- remove COW fixup mechanism completely; detect and fix changes to
pages outside of filesystem tracking, guaranteed since 5.8, grace
period is over
- remove 2K block size support, experimental to test subpage code on
x86_64 but now it would block folio changes
- tree-checker improvements of:
- free-space cache and tree items
- root reference and backref items
- extent state exceptions in reloc tree
- subpage mode updates:
- code optimizations, simplify tracking bitmaps
- re-enable readahead of compressed extent
- extend bitmap size to cover huge folios
- add tracepoints related to sync, tree-log and transactions
- device stats item tracking unification, remove item if there are no
stats recorded, also don't leave stale stats on replaced device
- allow extent buffer pages to be allocated as movable, to help page
migration
- added checks for proper extent buffer release
- btrfs.ko code size reduction due to transaction abort call
simplifications
- several struct size reductions
- more auto free conversions
- more verbose assertions"
* tag 'for-7.2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (130 commits)
btrfs: fix use-after-free after relocation failure with concurrent COW
btrfs: move WARN_ON on unexpected error in __add_tree_block()
btrfs: move locking into btrfs_get_reloc_bg_bytenr()
btrfs: lzo: reject compressed segment that overflows the compressed input
btrfs: retry faulting in the pages after a zero sized short direct write
btrfs: fix incorrect buffered IO fallback for append direct writes
btrfs: fix false IO failure after falling back to buffered write
btrfs: use verbose assertions in backref.c
btrfs: print a message when a missing device re-appears
btrfs: do not trim a device which is not writeable
btrfs: return real error after lookup failure in btrfs_ioctl_default_subvol()
btrfs: use mapping shared locking for reading super block
btrfs: use lockless read in nr_cached_objects shrinker callback
btrfs: switch local indicator variables to bools
btrfs: send: pass bool for pending_move and refs_processed parameters
btrfs: use shifts for sectorsize and nodesize
btrfs: fix deadlock cloning inline extent when using flushoncommit
btrfs: allocate eb-attached btree pages as movable
btrfs: add 32-bit compat ioctl for BTRFS_IOC_GET_SUBVOL_INFO
btrfs: derive f_fsid from on-disk fsid and dev_t
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs inode updates from Christian Brauner:
"This extends the lockless ->i_count handling.
iput() could already decrement any value greater than one locklessly
but acquiring a reference always required taking inode->i_lock. Now
acquiring a reference is lockless as long as the count was already at
least 1, i.e., only the 0->1 and 1->0 transitions take the lock.
This avoids the lock for the common cases of nfs calling into the
inode hash and btrfs using igrab(). Cleanup-wise icount_read_once() is
added to line up with inode_state_read_once() and the open-coded
->i_count loads across the tree are converted, and ihold() is
relocated and tidied up.
On top of that some stale lock ordering annotations are retired from
the inode hash code: iunique() no longer takes the hash lock since the
inode hash became RCU-searchable and s_inode_list_lock is no longer
taken under the hash lock either"
* tag 'vfs-7.2-rc1.inode' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
fs: retire stale lock ordering annotations from inode hash
fs: allow lockless ->i_count bumps as long as it does not transition 0->1
fs: relocate and tidy up ihold()
fs: add icount_read_once() and stop open-coding ->i_count loads
|
|
It does not make sense for the single caller to have the responsability
to lock the relocation mutex before calling the function and then have
the function to assert the lock is held. As this is a function in
relocation.c, move the locking details into it.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
[BUG]
The test case generic/362 will fail with "nodatasum" mount option (*):
MOUNT_OPTIONS -- -o nodatasum /dev/mapper/test-scratch1 /mnt/scratch
generic/362 0s ... - output mismatch (see /home/adam/xfstests/results//generic/362.out.bad)
--- tests/generic/362.out 2024-08-24 15:31:37.200000000 +0930
+++ /home/adam/xfstests/results//generic/362.out.bad 2026-05-27 10:21:17.574771567 +0930
@@ -1,2 +1,3 @@
QA output created by 362
+First write failed: Input/output error
Silence is golden
...
*: If the test case has been executed before with default data checksum,
the failure will not reproduce. Need the following fix to make it
reliably reproducible:
https://lore.kernel.org/linux-btrfs/20260528111659.87113-1-wqu@suse.com/
[CAUSE]
Inside __iomap_dio_rw(), the -EFAULT/-ENOTBLK error is not directly returned.
Thus we never got an error pointer from __iomap_dio_rw().
The call chain looks like this:
btrfs_direct_write()
|- btrfs_dio_write()
|- __iomap_dio_rw()
| |- iomap_iter()
| | |- btrfs_dio_iomap_begin()
| | Now an ordered extent is allocated for the 4K write.
| |
| |- iomi.status = iomap_dio_iter()
| | Where iomap_dio_iter() returned -EFAULT.
| |
| |- ret = iomap_iter()
| | |- btrfs_dio_iomap_end()
| | | |- btrfs_finish_ordered_extent(uptodate = false)
| | | | |- can_finish_ordered_extent()
| | | | |- btrfs_mark_ordered_extent_error()
| | | | |- mapping_set_error()
| | | | Now the address space is marked error.
| | | | return -ENOTBLK
| | |- return -ENOTBLK
| |- if (ret == -ENOTBLK) { ret = 0; }
| Now the return value is reset to 0.
| Thus no error pointer will be returned.
|
|- ret = iomap_dio_complete()
| Since no byte is submitted, @ret is 0.
|
|- Fallback to buffered IO
| And the buffered write finished without error
|
|- filemap_fdatawait_range()
|- filemap_check_errors()
The previous error is recorded, thus an error is returned
However the buffered write is properly submitted and finished, the error
is from the btrfs_finish_ordered_extent() call with @uptodate = false.
[FIX]
When a short dio write happened, any range that is submitted will have
btrfs_extract_ordered_extent() to be called, thus the submitted range
will always have an OE just covering the submitted range.
The remaining OE range is never submitted, thus they should be treated
as truncated, not an error. So that we can properly reclaim and not
insert an unnecessary file extent item, without marking the mapping as
error.
Extract a helper, btrfs_mark_ordered_extent_truncated(), and utilize
that helper to mark the direct IO ordered extent as truncated, so it
won't cause failure for the later buffered fallback.
[REASON FOR NO FIXES TAG]
The bug itself is pretty old, at commit f85781fb505e ("btrfs: switch to
iomap for direct IO") we're already passing @uptodate=false finishing
the OE.
But at that time OE with IOERR won't call mapping_set_error(), so it's
not exposed.
Later commit d61bec08b904 ("btrfs: mark ordered extent and inode with
error if we fail to finish") finally exposed the bug, but that commit
is doing a correct job, not the root cause.
Anyway the bug is very old, dating back to 5.1x days, thus only CC to
stable.
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
For all local indicator variables do simple switch to bool, done on all
files.
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Extent buffer pages allocated by alloc_extent_buffer() are attached to
btree_inode->i_mapping (the buffer_tree path), reach the LRU, and are
served by the btree_migrate_folio aops in fs/btrfs/disk-io.c. They are
migratable in practice once their owning extent buffer hits refs == 1,
which happens naturally. The buddy allocator classifies them by GFP,
however, and bare GFP_NOFS lands them in MIGRATE_UNMOVABLE pageblocks.
The result: every btree_inode page we read in pins an unmovable pageblock
from the page-superblock allocator's perspective, even though the page
itself can be moved.
Have each caller of btrfs_alloc_page_array, btrfs_alloc_folio_array,
and alloc_eb_folio_array pass in the full GFP mask directly, instead
of having the functions calculate it from boolean flags.
The alloc_extent_buffer call site passes GFP_NOFS | __GFP_NOFAIL |
__GFP_MOVABLE. All other call sites pass plain GFP_NOFS.
Three categories of caller stay on bare GFP_NOFS, deliberately:
- alloc_dummy_extent_buffer / btrfs_clone_extent_buffer: the
resulting eb is EXTENT_BUFFER_UNMAPPED, folio->mapping stays NULL,
the folios never enter LRU, never get migrate_folio aops. Tagging
them __GFP_MOVABLE would violate the page allocator's migrability
contract and they would defeat compaction in MOVABLE pageblocks
where isolate_migratepages_block skips non-LRU non-movable_ops
pages outright.
- btrfs_alloc_page_array callers in fs/btrfs/raid56.c (stripe
pages), fs/btrfs/inode.c (encoded reads), fs/btrfs/ioctl.c (io_uring
encoded reads), fs/btrfs/relocation.c (relocation buffers): same
contract violation. raid56 stripe_pages additionally persist in
the stripe cache (RBIO_CACHE_SIZE=1024) well beyond a single I/O,
so they are not transient enough to hand-wave the contract.
- btrfs_alloc_folio_array caller in fs/btrfs/scrub.c (stripe
folios): same -- stripe->folios[] are private buffers freed via
folio_put in release_scrub_stripe.
This change targets the dominant fragmentation source observed on the
page-superblock series: ~28 GB of btree_inode pages parked across
many tainted superpageblocks on a 250 GB test system with btrfs root,
preventing 1 GiB hugepage allocation from those regions. With the
movable hint, those pages now land in MOVABLE pageblocks where the
existing background defragger drains them through the standard
PB_has_movable gate, no LRU-sample fallback needed.
Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
should_nocow() reads inode->defrag_bytes without holding inode->lock,
while btrfs_set_delalloc_extent() and btrfs_clear_delalloc_extent()
update it under that spinlock.
This is a data race. The read is a quick check used to decide whether
to fall back to COW for a NOCOW inode: if defrag_bytes is non-zero and
the range is tagged EXTENT_DEFRAG, we force COW so that defragmentation
can rewrite the extent. Reading a stale value is harmless because:
- A missed increment may skip COW once, but the defrag pass will
redo the extent later.
- A stale non-zero may force an unnecessary COW, which is a minor
efficiency loss, not a correctness issue.
On 64-bit platforms an aligned u64 load is naturally atomic so tearing
cannot happen. On 32-bit platforms u64 may tear, but we only test for
zero vs non-zero, so the heuristic stays correct regardless. Use
data_race() annotation.
Fixes: 47059d930f0e ("Btrfs: make defragment work with nodatacow option")
Signed-off-by: Cen Zhang <zzzccc427@gmail.com>
[ Use data_race() instead of READ_ONCXE() ]
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
This is open-coded bvec_phys(), also remove direct use of bv_page.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Boris Burkov <boris@bur.io>
Tested-by: Boris Burkov <boris@bur.io>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Btrfs has an internal flag/subpage bitmap called ordered, which is to
indicate that a block has corresponding ordered extent covering it.
However this requires extra synchronization between the inode ordered
tree, and the folio flag/subpage bitmap, not to mention we need to
maintain the extra folio flag with subpage bitmap.
As a step to align btrfs_folio_state more closely to iomap_folio_state,
remove the btrfs specific ordered flag/bitmap.
This will also save us 64 bytes for the bitmap of a huge folio.
Since we're here, also update the ASCII graph of the bitmap, as there
are only 3 sub-bitmaps now, show all sub-bitmaps directly.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
This involves:
- The ASSERT() inside end_bbio_data_write()
It's only an ASSERT() and it has never been triggered as far as I
know.
- btrfs_migrate_folio()
Since all folio_test_ordered() usage will be removed, there is no need to
copy the folio ordered flag.
- The ASSERT() inside btrfs_invalidate_folio()
This one has its usefulness as it indeed caught some bugs during
development.
But that's the last user and will not be worth the folio flag or the
subpage bitmap.
This will allow btrfs to finally remove the ordered flags.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Currently there are only two folio ordered flag users:
- extent_writepage_io()
To ensure the folio range has an ordered extent covering it.
This is from the legacy COW fixup mechanism, which is already removed
and only a simple check is left.
- btrfs_invalidate_folio()
This is to avoid race with end_bbio_data_write(), where
btrfs_finish_ordered_extent() will be called to handle the OE
finishing.
But for btrfs_invalidate_folio() we have already waited for the folio
writeback to finish, and locked the folio.
This means we can use the dirty flag to check if a range is already
submitted or not.
If the OE range is not dirty, it means the range has been submitted and
its dirty flag was cleared. And since we have already waited for
writeback, the endio function will handle the OE finishing.
Thus if the range is not dirty, we must skip the range.
If the OE range is dirty, it means we have allocated an ordered extent but
have not yet submitted the range. And that's exactly the case where we need
to truncate the ordered extent.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Currently during folio writeback, we call folio_clear_dirty_for_io()
before extent_writepage(), which causes folio dirty flag to be cleared,
but without touching the subpage bitmaps.
This works fine for the bio submission path, as we always call
btrfs_folio_clear_dirty() to clear the subpage bitmap.
But this is far from consistent, thus this patch is going to unify the
behavior to always use btrfs_folio_clear_dirty() helper to clear both
folio flag and subpage bitmap.
This involves:
- Replace folio_clear_dirty_for_io() with folio_test_dirty()
There is only one call site calling folio_clear_dirty_for_io() outside
of subpage.c, that's inside extent_write_cache_pages() just before
extent_writepage().
- Make btrfs_invalidate_folio() clear dirty range for the whole folio
The function btrfs_invalidate_folio() is also called during
extent_writepage().
If we had a folio completely beyond isize, we call
folio_invalidate() -> btrfs_invalidate_folio() to free the folio.
Since we no longer have folio_clear_dirty_for_io() to clear the folio
dirty flag, we must manually clear the folio dirty flag for the
to-be-invalidated folio, and also clear the PAGECACHE_TAG_DIRTY tag.
The tag clearing is done using a new helper,
btrfs_clear_folio_dirty_tag(), which is almost the same as the old
btree_clear_folio_dirty_tag(), but with minor improvements including:
* Remove the folio_test_dirty() check
We have already done an ASSERT().
* Add an ASSERT() to make sure folio is mapped
- Add extra ASSERT()s before clearing folio private
During development I hit dirty folios without the private flag set,
and that caused a lot of ASSERT()s.
The reason is that btrfs_invalidate_folio() is relying on the dirty
flag being cleared when it's called from extent_writepage().
Add extra ASSERT()s inside clear_folio_extent_mapped() to catch
wild dirty/writeback flags.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
If statement branches that lead to a DEBUG_WARN() are unexpected to happen
and in most places we surround their expressions with the unlikely tag,
however a few places are missing. Add the unlikely tag to those missing
places to make it explicit to a reader that it's not expected and to hint
the compiler to generate better code.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
[WARNING]
When running test cases with injected errors or shutdown, e.g.
generic/388 or generic/475, there is a chance that the following kernel
warning is triggered:
BTRFS info (device dm-2): first mount of filesystem d8a19a28-3232-4809-b0df-38df83e71bff
BTRFS info (device dm-2): using crc32c checksum algorithm
BTRFS info (device dm-2): checking UUID tree
BTRFS info (device dm-2): turning on async discard
BTRFS info (device dm-2): enabling free space tree
BTRFS critical (device dm-2 state E): emergency shutdown
------------[ cut here ]------------
WARNING: extent_io.c:1742 at extent_writepage_io+0x437/0x520 [btrfs], CPU#2: kworker/u43:2/651591
CPU: 2 UID: 0 PID: 651591 Comm: kworker/u43:2 Tainted: G W OE 7.0.0-rc6-custom+ #365 PREEMPT(full) 5804053f02137e627472d94b5128cc9fcb110e88
RIP: 0010:extent_writepage_io+0x437/0x520 [btrfs]
Call Trace:
<TASK>
extent_write_cache_pages+0x2a5/0x820 [btrfs 70299925d0856939e93b17d480651713b3cbba58]
btrfs_writepages+0x74/0x130 [btrfs 70299925d0856939e93b17d480651713b3cbba58]
do_writepages+0xd0/0x160
__writeback_single_inode+0x42/0x340
writeback_sb_inodes+0x22d/0x580
wb_writeback+0xc6/0x360
wb_workfn+0xbd/0x470
process_one_work+0x198/0x3b0
worker_thread+0x1c8/0x330
kthread+0xee/0x120
ret_from_fork+0x2a6/0x330
ret_from_fork_asm+0x11/0x20
</TASK>
---[ end trace 0000000000000000 ]---
BTRFS error (device dm-2 state E): root 5 ino 259 folio 1323008 is marked dirty without notifying the fs
BTRFS error (device dm-2 state E): failed to submit blocks, root=5 inode=259 folio=1323008 submit_bitmap=0: -117
BTRFS info (device dm-2 state E): last unmount of filesystem d8a19a28-3232-4809-b0df-38df83e71bff
[CAUSE]
Inside btrfs we have the following pattern in several locations, for
example inside btrfs_dirty_folio():
btrfs_clear_extent_bit(&inode->io_tree, start_pos, end_of_last_block,
EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
cached);
ret = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
extra_bits, cached);
if (ret)
return ret;
However btrfs_set_extent_delalloc() can return IO errors other than -ENOMEM
through the following callchain:
btrfs_set_extent_delalloc()
\- btrfs_find_new_delalloc_bytes()
\- btrfs_get_extent()
\- btrfs_lookup_file_extent()
\- btrfs_search_slot()
When such IO error happened, the previous btrfs_clear_extent_bit() has
cleared the EXTENT_DELALLOC for the range, and we're expecting
btrfs_set_extent_delalloc() to re-set EXTENT_DELALLOC.
But since btrfs_set_extent_delalloc() failed before
btrfs_set_extent_bit(), EXTENT_DELALLOC flag is no longer present.
And if the folio range is dirty before entering
btrfs_set_extent_delalloc(), we got a dirty folio but no EXTENT_DELALLOC
flag now.
Then we hit the folio writeback:
extent_writepage()
|- writepage_delalloc()
| No ordered extent is created, as there is no EXTENT_DELALLOC set
| for the folio range.
| This also means the folio has no ordered flag set.
|
|- extent_writepage_io()
\- if (unlikely(!folio_test_ordered(folio))
Now we hit the warning.
[FIX]
Introduce a new helper, btrfs_reset_extent_delalloc() to replace the
currently open-coded btrfs_clear_extent_bit() +
btrfs_set_extent_delalloc() combination.
Instead of calling btrfs_clear_extent_bit() first, update
EXTENT_DELALLOC_NEW first, as that part can fail due to metadata IO,
meanwhile btrfs_clear_extent_bit() and btrfs_set_extent_bit() won't
return any error but retry memory allocation until succeeded.
This allows us to fail early without clearing EXTENT_DELALLOC bit, so
even if that new btrfs_reset_extent_delalloc() failed before touching
EXTENT_DELALLOC, the existing dirty range will still have their old
EXTENT_DELALLOC flag present, thus avoid the warning.
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
For a simple if + WARN_ON we should use the condition directly in the
macro.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
The folio checked flag is only utilized by the COW fixup mechanism
inside btrfs.
Since the COW fixup is already removed from non-experimental builds,
there is no need to keep the checked subpage bitmap.
This will saves us some space for large folios, for example for a single
256K sized large folio on 4K page sized systems:
Old bitmap size = 6 * (256K / 4K / 8) = 48 bytes
New bitmap size = 5 * (256K / 4K / 8) = 40 bytes
This will be more obvious when we're going to support huge folios (order
= 9).
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
[BACKGROUND]
Btrfs has a special mechanism called COW fixup, which detects dirty
pages without an ordered extent (folio ordered flag).
Normally a dirty folio must go through delayed allocation (delalloc)
before it can be submitted, and delalloc will create an ordered extent
for it and mark the range with ordered flag.
However in older kernels, there are bugs related to get_user_pages()
which can lead to some page marked dirty but without notifying the fs to
properly prepare them for writeback.
In that case without an ordered extent btrfs is unable to properly
submit such dirty folios, thus the COW fixup mechanism is introduced,
which do the extra space reservation so that they can be written back
properly.
[MODERN SOLUTIONS]
The MM layer has solved it properly now with the introduction of
pin_user_pages*(), so we're handling cases that are no longer valid.
So commit 7ca3e84980ef ("btrfs: reject out-of-band dirty folios during
writeback") is introduced to change the behavior from going through
COW fixup to rejecting them directly for experimental builds.
So far it works fine, but when errors are injected into the IO path, we
have random failures triggering the new warnings.
It looks like we have error path that cleared the ordered flag but
leaves the folio dirty flag, which later triggers the warning.
[REMOVAL OF COW FIXUP]
Although I hope to fix all those known warnings cases, I just can not
figure out the root cause yet.
But on the other hand, if we remove the ordered and checked flags in the
future, and purely rely on the dirty flags and ordered extent search, we
can get a much cleaner handling.
Considering it's no longer hitting the COW fixup for normal IO paths, I
think it's finally the time to remove the COW fixup completely.
Furthermore, the function name "btrfs_writepage_cow_fixup()" is no
longer meaningful, and since it's pretty small, only a folio flag check
with error message, there is no need to put it as a dedicated helper,
just open code it inside extent_writepage_io().
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
find_first_inode() and find_first_inode_to_shrink() lock root->inodes,
then loop over them, occasionally skipping some inodes. When they skip
an inode, they attempt to share the cpu/lock with cond_resched_lock().
However, that has a subtle problem associated with it.
cond_resched_lock() only drops the lock if it needs to actually call
schedule(). With CONFIG_PREEMPT_NONE, this means the full timeslice as
detected at ticks. With 8+ cpus and default tunables, this is 2.8ms. So
regardless of HZ, we will run for at least 2.8ms in this loop without
dropping the lock, assuming it finds no suitable inodes. If HZ is
small enough, it might be even worse as the tick granularity becomes
bigger than the timeslice.
The knock-on effect of this is that callers to
btrfs_del_inode_from_root() like kswapd trying to shrink the inode slab
or userspace threads calling evict() will spin on xa_lock(&root->inodes)
for 2.8ms, so the extent map shrinker dominates the lock even though
ostensibly it is intending to share it. This produces memory pressure as
there is only one kswapd and it runs sequentially so it can get stuck in
the inode slab shrinking.
To fix it, simply replace cond_resched_lock() with an open coded variant
which unconditionally does unlock/lock around cond_resched. Sharing the
lock is decoupled from sharing the CPU, and all the users of the lock
now share it fairly.
I was able to reproduce this on test systems by producing a lot of empty
files (to make a big root->inodes xarray), then producing memory
pressure by reading large files larger than ram, triggering kswapd and
the extent_map shrinker. The lock contention is visible with perf or
lockstat. This patch also relieved a user-apparent bottleneck on a
production system from the original report.
Tested-by: Rik van Riel <riel@surriel.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Similarly to inode_state_read_once(), it makes the caller spell out
they acknowledge instability of the returned value.
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://patch.msgid.link/20260421182538.1215894-2-mjguzik@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
When fallocate() with FALLOC_FL_KEEP_SIZE preallocates an extent past the
current i_size, the file_extent_tree of the inode is updated to cover
that range. However, on the next mount, btrfs_read_locked_inode() only
re-populates file_extent_tree with [0, round_up(i_size, sectorsize)),
losing the marks that belonged to the KEEP_SIZE prealloc extent beyond
i_size.
Later, when a non-KEEP_SIZE fallocate() extends i_size into / past that
old prealloc extent, the reservation loop in btrfs_fallocate() skips
already-prealloc segments and does not call into the path that marks the
file_extent_tree, so a gap remains inside the file_extent_tree across
[old_aligned_i_size, start_of_new_alloc). Then __btrfs_prealloc_file_range()
calls btrfs_inode_safe_disk_i_size_write(), which uses
find_contiguous_extent_bit() starting at offset 0 to derive disk_i_size.
The walk stops at the gap, so disk_i_size ends up smaller than i_size and
gets persisted. After the next mount, the file shows the wrong (smaller)
size.
The following reproducer triggers the problem:
$ cat test.sh
MNT=/mnt/sdi
DEV=/dev/sdi
mkdir -p $MNT
mkfs.btrfs -f -O ^no-holes $DEV
mount $DEV $MNT
touch $MNT/file1
# KEEP_SIZE prealloc beyond i_size (i_size stays 0)
fallocate -n -o 4M -l 4M $MNT/file1
umount $MNT
mount $DEV $MNT
# non-KEEP_SIZE fallocate that overlaps the previous prealloc tail
# and extends past it
fallocate -o 7M -l 2M $MNT/file1
ls -lh $MNT/file1
umount $MNT
mount $DEV $MNT
ls -lh $MNT/file1
umount $MNT
Running the reproducer gives the following result:
$ ./test.sh
(...)
-rw-rw-r-- 1 root root 9.0M May 4 16:35 /mnt/sdi/file1
-rw-rw-r-- 1 root root 7.0M May 4 16:35 /mnt/sdi/file1
The size before the second mount is correct (9M), but after the
remount it drops to 7M, i.e. the start of the gap inside file_extent_tree.
Fix this in __btrfs_prealloc_file_range() by marking the entire range
[round_down(old_i_size, sectorsize), round_up(new_i_size, sectorsize))
in file_extent_tree before updating i_size and calling
btrfs_inode_safe_disk_i_size_write(). This ensures the contiguous bit
search starting from 0 is not truncated by a stale gap left behind by a
previous KEEP_SIZE prealloc that was not restored on inode load.
The fix has no effect when the NO_HOLES feature is enabled because
btrfs_inode_safe_disk_i_size_write() and
btrfs_inode_set_file_extent_range()
both take the fast path that directly tracks disk_i_size without
consulting file_extent_tree.
Fixes: 9ddc959e802b ("btrfs: use the file extent tree infrastructure")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Robbie Ko <robbieko@synology.com>
[ Minor updates to the change log ]
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
submit_one_async_extent() calls btrfs_reserve_extent(), which decrements
bytes_may_use. If the call btrfs_create_io_em() fails, we jump to
out_free_reserve, which calls extent_clear_unlock_delalloc().
Because we're specifying EXTENT_DO_ACCOUNTING, i.e.
EXTENT_CLEAR_META_RESV | EXTENT_CLEAR_DATA_RESV, this decreases
bytes_may_use again. This can lead to problems later on, as an initial
write can fail only for the writeback to silently ENOSPC.
Fix this by replacing EXTENT_DO_ACCOUNTING with EXTENT_CLEAR_META_RESV.
This parallels a4fe134fc1d8eb ("btrfs: fix a double release on reserved
extents in cow_one_range()"), which is the same fix in cow_one_range().
Fixes: 151a41bc46df ("Btrfs: fix what bits we clear when erroring out from delalloc")
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
When removing a directory we are not updating its last_unlink_trans field,
which can result in incorrect fsync behaviour in case some one fsyncs the
directory after it was removed because it's holding a file descriptor on
it.
Example scenario:
mkdir /mnt/dir1
mkdir /mnt/dir1/dir2
mkdir /mnt/dir3
sync -f /mnt
# Do some change to the directory and fsync it.
chmod 700 /mnt/dir1
xfs_io -c fsync /mnt/dir1
# Move dir2 out of dir1 so that dir1 becomes empty.
mv /mnt/dir1/dir2 /mnt/dir3/
open fd on /mnt/dir1
call rmdir(2) on path "/mnt/dir1"
fsync fd
<trigger power failure>
When attempting to mount the filesystem, the log replay will fail with
an -EIO error and dmesg/syslog has the following:
[445771.626482] BTRFS info (device dm-0): first mount of filesystem 0368bbea-6c5e-44b5-b409-09abe496e650
[445771.626486] BTRFS info (device dm-0): using crc32c checksum algorithm
[445771.627912] BTRFS info (device dm-0): start tree-log replay
[445771.628335] page: refcount:2 mapcount:0 mapping:0000000061443ddc index:0x1d00 pfn:0x7072a5
[445771.629453] memcg:ffff89f400351b00
[445771.629892] aops:btree_aops [btrfs] ino:1
[445771.630737] flags: 0x17fffc00000402a(uptodate|lru|private|writeback|node=0|zone=2|lastcpupid=0x1ffff)
[445771.632359] raw: 017fffc00000402a fffff47284d950c8 fffff472907b7c08 ffff89f458e412b8
[445771.633713] raw: 0000000000001d00 ffff89f6c51d1a90 00000002ffffffff ffff89f400351b00
[445771.635029] page dumped because: eb page dump
[445771.635825] BTRFS critical (device dm-0): corrupt leaf: root=5 block=30408704 slot=10 ino=258, invalid nlink: has 2 expect no more than 1 for dir
[445771.638088] BTRFS info (device dm-0): leaf 30408704 gen 10 total ptrs 17 free space 14878 owner 5
[445771.638091] BTRFS info (device dm-0): refs 4 lock_owner 0 current 3581087
[445771.638094] item 0 key (256 INODE_ITEM 0) itemoff 16123 itemsize 160
[445771.638097] inode generation 3 transid 9 size 16 nbytes 16384
[445771.638098] block group 0 mode 40755 links 1 uid 0 gid 0
[445771.638100] rdev 0 sequence 2 flags 0x0
[445771.638102] atime 1775744884.0
[445771.660056] ctime 1775744885.645502983
[445771.660058] mtime 1775744885.645502983
[445771.660060] otime 1775744884.0
[445771.660062] item 1 key (256 INODE_REF 256) itemoff 16111 itemsize 12
[445771.660064] index 0 name_len 2
[445771.660066] item 2 key (256 DIR_ITEM 1843588421) itemoff 16077 itemsize 34
[445771.660068] location key (259 1 0) type 2
[445771.660070] transid 9 data_len 0 name_len 4
[445771.660075] item 3 key (256 DIR_ITEM 2363071922) itemoff 16043 itemsize 34
[445771.660076] location key (257 1 0) type 2
[445771.660077] transid 9 data_len 0 name_len 4
[445771.660078] item 4 key (256 DIR_INDEX 2) itemoff 16009 itemsize 34
[445771.660079] location key (257 1 0) type 2
[445771.660080] transid 9 data_len 0 name_len 4
[445771.660081] item 5 key (256 DIR_INDEX 3) itemoff 15975 itemsize 34
[445771.660082] location key (259 1 0) type 2
[445771.660083] transid 9 data_len 0 name_len 4
[445771.660084] item 6 key (257 INODE_ITEM 0) itemoff 15815 itemsize 160
[445771.660086] inode generation 9 transid 9 size 8 nbytes 0
[445771.660087] block group 0 mode 40777 links 1 uid 0 gid 0
[445771.660088] rdev 0 sequence 2 flags 0x0
[445771.660089] atime 1775744885.641174097
[445771.660090] ctime 1775744885.645502983
[445771.660091] mtime 1775744885.645502983
[445771.660105] otime 1775744885.641174097
[445771.660106] item 7 key (257 INODE_REF 256) itemoff 15801 itemsize 14
[445771.660107] index 2 name_len 4
[445771.660108] item 8 key (257 DIR_ITEM 2676584006) itemoff 15767 itemsize 34
[445771.660109] location key (258 1 0) type 2
[445771.660110] transid 9 data_len 0 name_len 4
[445771.660111] item 9 key (257 DIR_INDEX 2) itemoff 15733 itemsize 34
[445771.660112] location key (258 1 0) type 2
[445771.660113] transid 9 data_len 0 name_len 4
[445771.660114] item 10 key (258 INODE_ITEM 0) itemoff 15573 itemsize 160
[445771.660115] inode generation 9 transid 10 size 0 nbytes 0
[445771.660116] block group 0 mode 40755 links 2 uid 0 gid 0
[445771.660117] rdev 0 sequence 0 flags 0x0
[445771.660118] atime 1775744885.645502983
[445771.660119] ctime 1775744885.645502983
[445771.660120] mtime 1775744885.645502983
[445771.660121] otime 1775744885.645502983
[445771.660122] item 11 key (258 INODE_REF 257) itemoff 15559 itemsize 14
[445771.660123] index 2 name_len 4
[445771.660124] item 12 key (258 INODE_REF 259) itemoff 15545 itemsize 14
[445771.660125] index 2 name_len 4
[445771.660126] item 13 key (259 INODE_ITEM 0) itemoff 15385 itemsize 160
[445771.660127] inode generation 9 transid 10 size 8 nbytes 0
[445771.660128] block group 0 mode 40755 links 1 uid 0 gid 0
[445771.660129] rdev 0 sequence 1 flags 0x0
[445771.660130] atime 1775744885.645502983
[445771.660130] ctime 1775744885.645502983
[445771.660131] mtime 1775744885.645502983
[445771.660132] otime 1775744885.645502983
[445771.660133] item 14 key (259 INODE_REF 256) itemoff 15371 itemsize 14
[445771.660134] index 3 name_len 4
[445771.660135] item 15 key (259 DIR_ITEM 2676584006) itemoff 15337 itemsize 34
[445771.660136] location key (258 1 0) type 2
[445771.660137] transid 10 data_len 0 name_len 4
[445771.660138] item 16 key (259 DIR_INDEX 2) itemoff 15303 itemsize 34
[445771.660139] location key (258 1 0) type 2
[445771.660140] transid 10 data_len 0 name_len 4
[445771.660144] BTRFS error (device dm-0): block=30408704 write time tree block corruption detected
[445771.661650] ------------[ cut here ]------------
[445771.662358] WARNING: fs/btrfs/disk-io.c:326 at btree_csum_one_bio+0x217/0x230 [btrfs], CPU#8: mount/3581087
[445771.663588] Modules linked in: btrfs f2fs xfs (...)
[445771.671229] CPU: 8 UID: 0 PID: 3581087 Comm: mount Tainted: G W 7.0.0-rc6-btrfs-next-230+ #2 PREEMPT(full)
[445771.672575] Tainted: [W]=WARN
[445771.672987] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
[445771.674460] RIP: 0010:btree_csum_one_bio+0x217/0x230 [btrfs]
[445771.675222] Code: 89 44 24 (...)
[445771.677364] RSP: 0018:ffffd23882247660 EFLAGS: 00010246
[445771.678029] RAX: 0000000000000000 RBX: ffff89f6c51d1a90 RCX: 0000000000000000
[445771.678975] RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff89f406020000
[445771.679983] RBP: ffff89f821204000 R08: 0000000000000000 R09: 00000000ffefffff
[445771.680905] R10: ffffd23882247448 R11: 0000000000000003 R12: ffffd23882247668
[445771.681978] R13: ffff89f458e40fc0 R14: ffff89f737f4f500 R15: ffff89f737f4f500
[445771.682912] FS: 00007f0447a98840(0000) GS:ffff89fb9771d000(0000) knlGS:0000000000000000
[445771.684393] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[445771.685230] CR2: 00007f0447bf1330 CR3: 000000017cb02002 CR4: 0000000000370ef0
[445771.686273] Call Trace:
[445771.686646] <TASK>
[445771.686969] btrfs_submit_bbio+0x83f/0x860 [btrfs]
[445771.687750] ? write_one_eb+0x28f/0x340 [btrfs]
[445771.688428] btree_writepages+0x2e3/0x550 [btrfs]
[445771.689180] ? kmem_cache_alloc_noprof+0x12a/0x490
[445771.689963] ? alloc_extent_state+0x19/0x120 [btrfs]
[445771.690801] ? kmem_cache_free+0x135/0x380
[445771.691328] ? preempt_count_add+0x69/0xa0
[445771.691831] ? set_extent_bit+0x252/0x8e0 [btrfs]
[445771.692468] ? xas_load+0x9/0xc0
[445771.692873] ? xas_find+0x14d/0x1a0
[445771.693304] do_writepages+0xc6/0x160
[445771.693756] filemap_writeback+0xb8/0xe0
[445771.694274] btrfs_write_marked_extents+0x61/0x170 [btrfs]
[445771.694999] btrfs_write_and_wait_transaction+0x4e/0xc0 [btrfs]
[445771.695818] btrfs_commit_transaction+0x5c8/0xd10 [btrfs]
[445771.696530] ? kmem_cache_free+0x135/0x380
[445771.697120] ? release_extent_buffer+0x34/0x160 [btrfs]
[445771.697786] btrfs_recover_log_trees+0x7be/0x7e0 [btrfs]
[445771.698525] ? __pfx_replay_one_buffer+0x10/0x10 [btrfs]
[445771.699206] open_ctree+0x11e5/0x1810 [btrfs]
[445771.699776] btrfs_get_tree.cold+0xb/0x162 [btrfs]
[445771.700463] ? fscontext_read+0x165/0x180
[445771.701146] ? rw_verify_area+0x50/0x180
[445771.701866] vfs_get_tree+0x25/0xd0
[445771.702491] vfs_cmd_create+0x59/0xe0
[445771.703125] __do_sys_fsconfig+0x303/0x610
[445771.703603] do_syscall_64+0xe9/0xf20
[445771.703974] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[445771.704700] RIP: 0033:0x7f0447cbd4aa
[445771.705108] Code: 73 01 c3 (...)
[445771.707263] RSP: 002b:00007ffc4e528318 EFLAGS: 00000246 ORIG_RAX: 00000000000001af
[445771.708107] RAX: ffffffffffffffda RBX: 00005561585d8c20 RCX: 00007f0447cbd4aa
[445771.708931] RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000003
[445771.709744] RBP: 00005561585d9120 R08: 0000000000000000 R09: 0000000000000000
[445771.710674] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
[445771.711477] R13: 00007f0447e4f580 R14: 00007f0447e5126c R15: 00007f0447e36a23
[445771.712277] </TASK>
[445771.712541] ---[ end trace 0000000000000000 ]---
[445771.713382] BTRFS error (device dm-0): error while writing out transaction: -5
[445771.714679] BTRFS warning (device dm-0): Skipping commit of aborted transaction.
[445771.715562] BTRFS error (device dm-0 state A): Transaction aborted (error -5)
[445771.716459] BTRFS: error (device dm-0 state A) in cleanup_transaction:2068: errno=-5 IO failure
[445771.717936] BTRFS error (device dm-0 state EA): failed to recover log trees with error: -5
[445771.719681] BTRFS error (device dm-0 state EA): open_ctree failed: -5
The problem is that such a fsync should have result in a fallback to a
transaction commit, but that did not happen because through the
btrfs_rmdir() we never update the directory's last_unlink_trans field.
Any inode that had a link removed must have its last_unlink_trans updated
to the ID of transaction used for the operation, otherwise fsync and log
replay will not work correctly.
btrfs_rmdir() calls btrfs_unlink_inode() and through that call chain we
never call btrfs_record_unlink_dir() in order to update last_unlink_trans.
However btrfs_unlink(), which is used for unlinking regular files, calls
btrfs_record_unlink_dir() and then calls btrfs_unlink_inode(). So fix
this by moving the call to btrfs_record_unlink_dir() from btrfs_unlink()
to btrfs_unlink_inode().
A test case for fstests will follow soon.
Reported-by: Slava0135 <slava.kovalevskiy.2014@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/CAAJYhww5ov62Hm+n+tmhcL-e_4cBobg+OWogKjOJxVUXivC=MQ@mail.gmail.com/
CC: stable@vger.kernel.org
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
In btrfs_finish_one_ordered(), clear_bits is unconditionally initialized
with EXTENT_DEFRAG. For NOCOW ordered extents this is always a no-op
because should_nocow() already forces the COW path when EXTENT_DEFRAG is
set, so a NOCOW ordered extent can never have EXTENT_DEFRAG on its range.
Although harmless, the unconditional btrfs_clear_extent_bit() call still
performs a cold rbtree lookup under the io tree spinlock on every NOCOW
write completion. Avoid this by only adding EXTENT_DEFRAG to clear_bits
for non-NOCOW ordered extents, and skip the call entirely when there are
no bits to clear.
Signed-off-by: Dave Chen <davechen@synology.com>
Signed-off-by: Robbie Ko <robbieko@synology.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Having the filesystem in an error state, meaning we had a transaction
abort, is unexpected. Mark every check for the error state with the
unlikely annotation to convey that and to allow the compiler to generate
better code.
On x86_64, using gcc 14.2.0-19 from Debian, resulted in a slightly
reduced object size and better code.
Before:
$ size fs/btrfs/btrfs.ko
text data bss dec hex filename
2008598 175912 15592 2200102 219226 fs/btrfs/btrfs.ko
After:
$ size fs/btrfs/btrfs.ko
text data bss dec hex filename
2008450 175912 15592 2199954 219192 fs/btrfs/btrfs.ko
Reviewed-by: Anand Jain <asj@kernel.org>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Under memory pressure, direct reclaim can kick in during compressed
readahead. This puts the associated task into D-state. Then shrink_lruvec()
disables interrupts when acquiring the LRU lock. Under heavy pressure,
we've observed reclaim can run long enough that the CPU becomes prone to
CSD lock stalls since it cannot service incoming IPIs. Although the CSD
lock stalls are the worst case scenario, we have found many more subtle
occurrences of this latency on the order of seconds, over a minute in some
cases.
Prevent direct reclaim during compressed readahead. This is achieved by
using different GFP flags at key points when the bio is marked for
readahead.
There are two functions that allocate during compressed readahead:
btrfs_alloc_compr_folio() and add_ra_bio_pages(). Both currently use
GFP_NOFS which includes __GFP_DIRECT_RECLAIM.
For the internal API call btrfs_alloc_compr_folio(), the signature changes
to accept an additional gfp_t parameter. At the readahead call site, it
gets flags similar to GFP_NOFS but stripped of __GFP_DIRECT_RECLAIM.
__GFP_NOWARN is added since these allocations are allowed to fail. Demand
reads still use full GFP_NOFS and will enter reclaim if needed. All other
existing call sites of btrfs_alloc_compr_folio() now explicitly pass
GFP_NOFS to retain their current behavior.
add_ra_bio_pages() gains a bool parameter which allows callers to specify
if they want to allow direct reclaim or not. In either case, the
__GFP_NOWARN flag was added unconditionally since the allocations are
speculative.
There has been some previous work done on calling add_ra_bio_pages() [0].
This patch is complementary: where that patch reduces call frequency, this
patch reduces the latency associated with those calls.
[0] https://lore.kernel.org/linux-btrfs/656838ec1232314a2657716e59f4f15a8eadba64.1751492111.git.boris@bur.io/
Reviewed-by: Mark Harmstone <mark@harmstone.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: JP Kobryn (Meta) <jp.kobryn@linux.dev>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
In btrfs_setsize(), when a file is truncated to size 0, the
BTRFS_INODE_FLUSH_ON_CLOSE flag is unconditionally set to ensure
pending writes get flushed on close. This flag was designed to protect
the "truncate-then-rewrite" pattern, where an application truncates a
file with existing data down to zero and writes new content, ensuring
the new data reach disk on close.
However, when a file already has a size of 0 (e.g. a newly created
file opened with O_CREAT | O_TRUNC), oldsize and newsize are both 0.
In this case, setting BTRFS_INODE_FLUSH_ON_CLOSE is unnecessary because
no "good data" was truncated away. The subsequent filemap_flush() in
btrfs_release_file() then triggers avoidable writeback that disrupts
the normal delayed writeback batching, adding I/O overhead.
This comes from a real workload. A backup service creates temporary
files via mkstemp(), closes them, and later reopens them with O_TRUNC
for writing. The O_TRUNC is defensive. The file creation and usage is
done by a different component, so removing the unneeded truncation is
not straightforward. This pattern repeats for a large number of files
each close() triggers an unnecessary filemap_flush().
Signed-off-by: Dave Chen <davechen@synology.com>
Signed-off-by: Robbie Ko <robbieko@synology.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Prefer using IS_ERR_OR_NULL() over using IS_ERR() and a manual NULL
check.
IS_ERR_OR_NULL() already uses likely(!ptr) internally. checkpatch does
not like nesting it:
> WARNING: nested (un)?likely() calls, IS_ERR_OR_NULL already uses
> unlikely() internally
Remove the explicit use of likely().
Change generated with coccinelle.
Signed-off-by: Philipp Hahn <phahn-oss@avm.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Currently we call cow_file_range_inline() in different situations, from
regular cow_file_range() to compress_file_range().
This is because inline extent creation has different conditions based on
whether it's a compressed one or not.
But on the other hand, inline extent creation shouldn't be so
distributed, we can just have a dedicated branch in
btrfs_run_delalloc_range().
It will become more obvious for compressed inline cases, it makes no
sense to go through all the complex async extent mechanism just to
inline a single block.
So here we introduce a dedicated run_delalloc_inline() helper, and
remove all inline related handling from cow_file_range() and
compress_file_range().
There is a special update to inode_need_compress(), that a new
@check_inline parameter is introduced.
This is to allow inline specific checks to be done inside
run_delalloc_inline(), which allows single block compression, but
other call sites should always reject single block compression.
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
We have two locations using open-coded 512K size, as the async chunk
size.
For compression we have not only the max size a compressed extent can
represent (128K), but also how large an async chunk can be (512K).
Although we have a macro for the maximum compressed extent size, we do
not have any macro for the async chunk size.
Add such a macro and replace the two open-coded SZ_512K.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Currently we zero out all the remaining bytes of the last folio of
the compressed bio, then round the bio size to fs block boundary.
But that is done in two different functions, zero_last_folio() to zero
the remaining bytes of the last folio, and round_up_last_block() to
round up the bio to fs block boundary.
There are some minor problems:
- zero_last_folio() is zeroing ranges we won't submit
This is mostly affecting block size < page size cases, where we can
have a large folio (e.g. 64K), but the fs block size is only 4K.
In that case, we may only want to submit the first 4K of the folio,
the remaining range won't matter, but we still zero them all.
This causes unnecessary CPU usage just to zero out some bytes we won't
utilized.
- compressed_bio_last_folio() is called twice in two different functions
Which in theory we only need to call it once.
Enhance the situation by:
- Only zero out bytes up to the fs block boundary
Thus this will reduce some overhead for bs < ps cases.
- Move the folio_zero_range() call into round_up_last_block()
So that we can reuse the same folio returned by
compressed_bio_last_folio().
Reviewed-by: Anand Jain <asj@kernel.org>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
When a snapshot is being created, the atomic counter snapshot_force_cow
is incremented to force incoming writes to fallback to COW. This is a
critical mechanism to protect the consistency of the snapshot being taken.
Currently, can_nocow_file_extent() checks this counter only after
performing several checks, most notably the expensive cross-reference
check via btrfs_cross_ref_exist(). btrfs_cross_ref_exist() releases the
path and performs a search in the extent tree or backref cache, which
involves btree traversals and locking overhead.
Moves the snapshot_force_cow check to the very beginning of
can_nocow_file_extent().
This reordering is safe and beneficial because:
1. args->writeback_path is invariant for the duration of the call (set
by caller run_delalloc_nocow).
2. is_freespace_inode is a static property of the inode.
3. The state of snapshot_force_cow is driven by the btrfs_mksnapshot()
process. Checking it earlier does not change the outcome of the NOCOW
decision, but effectively prunes the expensive code path when a
fallback to COW is inevitable.
By failing fast when a snapshot is pending, we avoid the unnecessary
overhead of btrfs_cross_ref_exist() and other extent item checks in the
scenario where NOCOW is already known to be impossible.
Signed-off-by: Chen Guan Jie <jk.chen1095@gmail.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
