15244 Commits
Author SHA1 Message Date
Linus Torvalds 400544639d Merge tag 'for-7.1-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
 "A batch of fixes to simple quotas:

   - add conditional rescheduling point not dependent on the lock during
     inode iterations to avoid delays with PREEMPT_NONE enabled

   - fix subvolume deletion so it does not break the squota invariants

   - properly handle enabling squota, tracking extents in the initial
     transaction

   - catch and warn about underflows, clamp to zero to avoid further
     problems

  And one fix to inode size handling:

   - fix handling of preallocated extents beyond i_size when not using
     the no-holes feature"

* tag 'for-7.1-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: swallow btrfs_record_squota_delta() ENOENT
  btrfs: clamp to avoid squota underflow
  btrfs: fix squota accounting during enable generation
  btrfs: check for subvolume before deleting squota qgroup
  btrfs: always drop root->inodes lock before cond_resched()
  btrfs: mark file extent range dirty after converting prealloc extents
2026-05-23 16:54:48 -07:00
Boris Burkov f13342e15d btrfs: swallow btrfs_record_squota_delta() ENOENT
I thought that it was likely I could harden squota deletion to the point
that it was impossible to end up with an extent accounted to a qgroup
outliving its qgroup. Several recent bugs have made me re-consider that
position.

Ultimately, this is a tradeoff between short term stability and long
term strictness, but I think given that there could be another layer of
bugs behind the 2-3 I just fixed, I would feel much more confident in
people using squotas if the risk was "your values can get a bit out of
whack which you can fix by deleting stuff or
disabling/re-enabling/repairing" vs "it will abort your filesystem".

As the final nail in the coffin, the Meta production kernel was lacking
earlier fixes from me and Qu regarding subvol qgroup lifetime, so this
is what we have been testing at scale, so I think at least for now
upstream should have the same extra layer of protection.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-05-16 03:08:40 +02:00
Boris Burkov 99aacd1951 btrfs: clamp to avoid squota underflow
Simple quota accounting can undercount metadata tree block allocations
in certain scenarios. When an undercounted subvolume is deleted and its
tree blocks freed, the free deltas decrement rfer/excl past zero,
wrapping the u64 to a value near U64_MAX.

Once wrapped, can_delete_squota_qgroup() sees non-zero rfer and refuses
to delete the qgroup. The qgroup becomes permanently orphaned in the
quota tree, since there is no subvolume left to generate frees that
would bring the counter back to zero.

While we ultimately want to fix any mis-accounting at the source, it is
also helpful and worthwhile to mitigate the damage by clamping rfer and
excl to zero on underflow rather than allowing the u64 to wrap. This at
least allows us to clean up the messed up qgroups on subvol deletion.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-05-16 03:07:20 +02:00
Boris Burkov d7c6005548 btrfs: fix squota accounting during enable generation
The first transaction that enables squotas is special and a bit tricky.
We have to set BTRFS_FS_QUOTA_ENABLED after the transaction to avoid a
deadlock, so any delayed refs that run before we set the bit are not
squota accounted. For data this is fine, we don't get an owner_ref, so
there is no real harm, it's as if the extent predated squotas. However
for metadata, the tree block will have gen == enable_gen so when we free
it later, we will decrement the squota accounting, which can result in
an underflow. Before it is freed, btrfs check shows errors, as we have
mismatched usage between the node generations/owners and the squota
values.

There are two angles to this fix:

1. For extents that come in delayed_refs that run during the
   enable_gen transaction, we must actually set enable_gen to the *next*
   transaction. That is the first transaction that we can really
   properly account in any way.
2. For extents that come in between the end of our transaction handle
   and the time we set the BTRFS_FS_QUOTA_ENABLED bit, we need an
   additional bit, BTRFS_FS_SQUOTA_ENABLING which only affects recording
   squota deltas, so we do pick up those extents. Otherwise, we would
   miss them, even for enable_gen + 1.

Fixes: bd7c1ea3a3 ("btrfs: qgroup: check generation when recording simple quota delta")
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-05-16 03:07:19 +02:00
Boris Burkov 1e92637722 btrfs: check for subvolume before deleting squota qgroup
The invariant that we want to maintain with subvolume qgroups is that
the qgroup can only be deleted if there is no root. With squotas, we
thought that it was sufficient to just check the usage, because we
assumed that deleting a subvolume will drive it's qgroups usage to 0,
and thus 0 usage implies no subvolume.

However, this is false, for two reasons:

- A subvol whose extents are all from before squotas was enabled.
- A subvol that was created in this transaction and for which we have
  not yet run any delayed refs.

In both cases, deleting the qgroup breaks the desired invariant and we
are left with a subvolume with no qgroup but squotas are enabled.

Fix this by unifying the deletion check logic between full qgroups and
squotas. Squotas do all the same checks *and* the additional usage == 0
check, which is the one extra rule peculiar to squotas.

Link: https://lore.kernel.org/linux-btrfs/adnBhWfJQ1n3hZC8@merlins.org/
Fixes: a8df356199 ("btrfs: forbid deleting live subvol qgroup")
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-05-16 03:07:17 +02:00
Boris Burkov 975e63c7a8 btrfs: always drop root->inodes lock before cond_resched()
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>
2026-05-16 03:06:56 +02:00
Robbie Ko 080ecbd054 btrfs: mark file extent range dirty after converting prealloc extents
When writing into a preallocated extent, ordered extent completion calls
btrfs_mark_extent_written() to convert the file extent item from the
BTRFS_FILE_EXTENT_PREALLOC type to the BTRFS_FILE_EXTENT_REG type.

If the preallocated extent was created beyond i_size with fallocate
keep-size, and the inode is evicted and loaded again before the write,
the inode's file_extent_tree is initialized only up to i_size.

The beyond i_size prealloc extent is therefore not tracked there.

After a write into that extent extends i_size, btrfs_mark_extent_written()
updates the file extent item, but the corresponding range is not marked
dirty in the inode's file_extent_tree.

This can leave disk_i_size stale when the filesystem does not use the
no-holes feature, so after remount the file size can go back to the old
value.

The following reproducer triggers the problem:

  $ cat test.sh
  #!/bin/bash

  DEV=/dev/sdi
  MNT=/mnt/sdi

  mkfs.btrfs -f -O ^no-holes $DEV
  mount $DEV $MNT

  touch $MNT/file
  fallocate -n -l 2M $MNT/file

  umount $MNT
  mount $DEV $MNT

  dd if=/dev/zero of=$MNT/file bs=1M count=1 conv=notrunc
  ls -lh $MNT/file

  umount $MNT
  mount $DEV $MNT

  ls -lh $MNT/file
  umount $MNT

Running the reproducer gives the following result:

  $ ./test.sh
  (...)
  1048576 bytes (1.0 MB, 1.0 MiB) copied, 0.000596024 s, 1.8 GB/s
  -rw-rw-r-- 1 root root 1.0M May  8 16:34 /mnt/sdi/file
  -rw-rw-r-- 1 root root 0 May  8 16:34 /mnt/sdi/file

Fix this by marking the written range dirty in the inode's
file_extent_tree after successfully converting the prealloc extent to a
regular extent.

Fixes: 9ddc959e80 ("btrfs: use the file extent tree infrastructure")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Robbie Ko <robbieko@synology.com>
[ Minor change log updates ]
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-05-16 03:06:37 +02:00
Linus Torvalds a8b0b72255 Merge tag 'for-7.1-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:

 - fixup warning when allocating memory for readahead, __GFP_NOWARN was
   accidentally dropped when setting mapping constraints

 - in tracepoint of file sync, fix sleeping in atomic context when
   handling dentries

 - harden initial loading of block group on crafted/fuzzed images,
   iterate all chunk mapping entries unconditionally

 - fix freeing pages of submitted io after checking for errors

 - fix incorrect inode size after remount when using fallocate KEEP_SIZE
   mode (also requires disabled 'no-holes' feature)

* tag 'for-7.1-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix incorrect i_size after remount caused by KEEP_SIZE prealloc gap
  btrfs: only release the dirty pages io tree after successful writes
  btrfs: tracepoints: fix sleep while in atomic context in btrfs_sync_file()
  btrfs: always pass __GFP_NOWARN from add_ra_bio_pages()
  btrfs: fix check_chunk_block_group_mappings() to iterate all chunk maps
2026-05-15 13:22:07 -07:00
Robbie Ko c562ba61fc btrfs: fix incorrect i_size after remount caused by KEEP_SIZE prealloc gap
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: 9ddc959e80 ("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>
2026-05-08 00:32:08 +02:00
Qu Wenruo 4066c55e10 btrfs: only release the dirty pages io tree after successful writes
[WARNING]
With extra warning on dirty extent buffers at umount (aka, the next
patch in the series), test case generic/388 can trigger the following
warning about dirty extent buffers at unmount time:

  BTRFS critical (device dm-2 state E): emergency shutdown
  BTRFS error (device dm-2 state E): error while writing out transaction: -30
  BTRFS warning (device dm-2 state E): Skipping commit of aborted transaction.
  BTRFS error (device dm-2 state EA): Transaction 9 aborted (error -30)
  BTRFS: error (device dm-2 state EA) in cleanup_transaction:2068: errno=-30 Readonly filesystem
  BTRFS info (device dm-2 state EA): forced readonly
  BTRFS info (device dm-2 state EA): last unmount of filesystem 4fbf2e15-f941-49a0-bc7c-716315d2777c
  ------------[ cut here ]------------
  WARNING: disk-io.c:3311 at invalidate_and_check_btree_folios+0xfd/0x1ca [btrfs], CPU#8: umount/914368
  CPU: 8 UID: 0 PID: 914368 Comm: umount Tainted: G           OE       7.1.0-rc1-custom+ #372 PREEMPT(full)  2de38db8d1deae71fde295430a0ff3ab98ccf596
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 02/02/2022
  RIP: 0010:invalidate_and_check_btree_folios+0xfd/0x1ca [btrfs]
  Call Trace:
   <TASK>
   close_ctree+0x52e/0x574 [btrfs d2f0b1cd330d1287e7a9919d112eadfc0e914efd]
   generic_shutdown_super+0x89/0x1a0
   kill_anon_super+0x16/0x40
   btrfs_kill_super+0x16/0x20 [btrfs d2f0b1cd330d1287e7a9919d112eadfc0e914efd]
   deactivate_locked_super+0x2d/0xb0
   cleanup_mnt+0xdc/0x140
   task_work_run+0x5a/0xa0
   exit_to_user_mode_loop+0x123/0x4b0
   do_syscall_64+0x243/0x7c0
   entry_SYSCALL_64_after_hwframe+0x4b/0x53
   </TASK>
  ---[ end trace 0000000000000000 ]---
  BTRFS warning (device dm-2 state EA): unable to release extent buffer 30539776 owner 9 gen 9 refs 2 flags 0x7
  BTRFS warning (device dm-2 state EA): unable to release extent buffer 30621696 owner 257 gen 9 refs 2 flags 0x7
  BTRFS warning (device dm-2 state EA): unable to release extent buffer 30638080 owner 258 gen 9 refs 2 flags 0x7
  BTRFS warning (device dm-2 state EA): unable to release extent buffer 30654464 owner 7 gen 9 refs 2 flags 0x7
  BTRFS warning (device dm-2 state EA): unable to release extent buffer 30703616 owner 2 gen 9 refs 2 flags 0x7
  BTRFS warning (device dm-2 state EA): unable to release extent buffer 30720000 owner 10 gen 9 refs 2 flags 0x7
  BTRFS warning (device dm-2 state EA): unable to release extent buffer 30736384 owner 4 gen 9 refs 2 flags 0x7
  BTRFS warning (device dm-2 state EA): unable to release extent buffer 30752768 owner 11 gen 9 refs 2 flags 0x7

I'm using a stripped down version, which seems to trigger the warning
more reliably:

  _fsstress_pid=""
  workload()
  {
  	dmesg -C
  	mkfs.btrfs -f -K $dev > /dev/null
  	echo 1 > /sys/kernel/debug/clear_warn_once
  	mount $dev $mnt
  	$fsstress -w -n 1024 -p 4 -d $mnt &
  	_fsstress_pid=$!
  	sleep 0
  	$godown $mnt
  	pkill --echo -PIPE fsstress > /dev/null
  	wait $_fsstress_pid
  	unset _fsstress_pid
  	umount $mnt

  	if dmesg | grep -q "WARNING"; then
  		fail
  	fi
  }

  for (( i = 0; i < $runtime; i++ )); do
  	echo "=== $i/$runtime ==="
  	workload
  done

[CAUSE]
Inside btrfs_write_and_wait_transaction(), we first try to write all
dirty ebs, then wait for them to finish.

After that we call btrfs_extent_io_tree_release() to free all
extent states from dirty_pages io tree.

However if we hit an error from btrfs_write_marked_extent(), then we
still call btrfs_extent_io_tree_release() to clear that dirty_pages io
tree, which may contain dirty records that we haven't yet submitted.

Furthermore, the later transaction cleanup path will utilize that
dirty_pages io tree to properly cleanup those dirty ebs, but since it's
already empty, no dirty ebs are properly cleaned up, thus will later
trigger the warnings inside invalidate_btree_folios().

[FIX]
Normally such dirty ebs won't cause problems, as when the iput() is
called on the btree inode, the dirty ebs will be forcibly written back,
and since the fs is already in an error status, such writeback will not
reach disk and finish immediately.

But it's still better to get rid of such dirty ebs, if we ended up with
dirty ebs but the fs is not in an error status, then such writeback at
iput() time will be too late, as all workers are already stopped but
writeback will utilize workers, which will lead to NULL pointer
dereferences.

Instead of unconditionally calling btrfs_extent_io_tree_release(), only
call it if btrfs_write_and_wait_transaction() finished successfully, so
that @dirty_pages extent io tree is kept untouched for transaction
cleanup.

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>
2026-05-08 00:31:47 +02:00
Calvin Owens 4822703b15 btrfs: always pass __GFP_NOWARN from add_ra_bio_pages()
A build workload newly prints order-0 allocation failures on 7.1-rc1:

    sh: page allocation failure: order:0
    mode:0x14084a(__GFP_HIGHMEM|__GFP_MOVABLE|__GFP_IO|__GFP_KSWAPD_RECLAIM|
                  __GFP_COMP|__GFP_HARDWALL)
    CPU: 27 UID: 1000 PID: 855540 Comm: sh Not tainted 7.1.0-rc1-llvm-00058-gdca922e019dd #1 PREEMPTLAZY
    Call Trace:
     <TASK>
     dump_stack_lvl+0x50/0x70
     warn_alloc+0xeb/0x100
     __alloc_pages_slowpath+0x567/0x5a0
     ? filemap_get_entry+0x11a/0x140
     __alloc_frozen_pages_noprof+0x249/0x2d0
     alloc_pages_mpol+0xe4/0x180
     folio_alloc_noprof+0x80/0xa0
     add_ra_bio_pages+0x13c/0x4b0
     btrfs_submit_compressed_read+0x229/0x300
     submit_one_bio+0x9e/0xe0
     btrfs_readahead+0x185/0x1a0
     [...]

    (lldb) source list -a add_ra_bio_pages+0x13c
    .../vmlinux.unstripped add_ra_bio_pages + 316 at .../fs/btrfs/compression.c:454:8
       451
       452                  folio = filemap_alloc_folio(mapping_gfp_constraint(mapping, constraint_gfp),
       453                                              0, NULL);
    -> 454                  if (!folio)
       455                          break;

I can reproduce this consistently by running a memory hog concurrently
with a buffered writer on a machine with a very large amount of swap.

Commit 7ae37b2c94 ("btrfs: prevent direct reclaim during compressed
readahead") clearly intended to suppress these warnings. But because the
mask set in the address_space with mapping_set_gfp_mask() doesn't include
__GFP_NOWARN, mapping_gfp_constraint() removes it from constraint_gfp
before it is passed to filemap_alloc_folio().

Fix by refactoring the code to add __GFP_NOWARN after the call to
mapping_gfp_constraint().

Fixes: 7ae37b2c94 ("btrfs: prevent direct reclaim during compressed readahead")
Signed-off-by: Calvin Owens <calvin@wbinvd.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-05-08 00:30:53 +02:00
ZhengYuan Huang fc51cba3eb btrfs: fix check_chunk_block_group_mappings() to iterate all chunk maps
[BUG]
A corrupted image with a chunk present in the chunk tree but whose
corresponding block group item is missing from the extent tree can be
mounted successfully, even though check_chunk_block_group_mappings()
is supposed to catch exactly this corruption at mount time.  Once
mounted, running btrfs balance with a usage filter (-dusage=N or
-dusage=min..max) triggers a null-ptr-deref:

  KASAN: null-ptr-deref in range [0x0000000000000070-0x0000000000000077]
    RIP: 0010:chunk_usage_filter fs/btrfs/volumes.c:3874 [inline]
    RIP: 0010:should_balance_chunk fs/btrfs/volumes.c:4018 [inline]
    RIP: 0010:__btrfs_balance fs/btrfs/volumes.c:4172 [inline]
    RIP: 0010:btrfs_balance+0x2024/0x42b0 fs/btrfs/volumes.c:4604

[CAUSE]
The crash occurs because __btrfs_balance() iterates the on-disk chunk
tree, finds the orphaned chunk, calls chunk_usage_filter() (or
chunk_usage_range_filter()), which queries the in-memory block group
cache via btrfs_lookup_block_group().  Since no block group was ever
inserted for this chunk, the lookup returns NULL, and the subsequent
dereference of cache->used crashes.

check_chunk_block_group_mappings() uses btrfs_find_chunk_map() to
iterate the in-memory chunk map (fs_info->mapping_tree):

  map = btrfs_find_chunk_map(fs_info, start, 1);

With @start = 0 and @length = 1, btrfs_find_chunk_map() looks for a
chunk map that *contains* the logical address 0. If no chunk contains
logical address 0, btrfs_find_chunk_map(fs_info, 0, 1) returns NULL
immediately and the loop breaks after the very first iteration,
having checked zero chunks. The entire verification function is therefore
a no-op, and the corrupted image passes the mount-time check undetected.

[FIX]
Replace the btrfs_find_chunk_map() based loop with a direct in-order
walk of fs_info->mapping_tree using rb_first_cached() + rb_next().
This guarantees that every chunk map in the tree is visited regardless
of the logical addresses involved.

No lock is taken around the traversal. This function is called during
mount from btrfs_read_block_groups(), which is invoked from open_ctree()
before any background threads (cleaner, transaction kthread, etc.) are
started. There are therefore no concurrent writers that could modify
mapping_tree at this point. An analogous lockless direct traversal of
mapping_tree already exists in fill_dummy_bgs() in the same file.

Since we walk the rb-tree directly via rb_entry() without going through
btrfs_find_chunk_map(), no reference is taken on each map entry, so the
btrfs_free_chunk_map() calls are also removed.

Signed-off-by: ZhengYuan Huang <gality369@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-05-08 00:29:07 +02:00
Linus Torvalds 73082fbdb1 Merge tag 'for-7.1-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:

 - space reservation fixes:
     - correctly undo 'may_use' accounting for remap tree
     - avoid double decrement of 'may_use' when submitting async io

 - actually enable the shutdown ioctl callback (not just the superblock
   ops)

 - raid stripe tree fixes when deleting extents
     - add missing error handling
     - fix various incorrect values set

 - fix transaction state when removing a directory, possibly leading to
   EIO during log replay

 - additional b-tree node key checks during metadata readahead

 - error handling and transaction abort updates

* tag 'for-7.1-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix double-decrement of bytes_may_use in submit_one_async_extent()
  btrfs: check return value of btrfs_partially_delete_raid_extent()
  btrfs: handle -EAGAIN from btrfs_duplicate_item and refresh stale leaf pointer
  btrfs: replace ASSERT with proper error handling in stripe lookup fallback
  btrfs: fix wrong min_objectid in btrfs_previous_item() call
  btrfs: fix raid stripe search missing entries at leaf boundaries
  btrfs: copy devid in btrfs_partially_delete_raid_extent()
  btrfs: handle unexpected free-space-tree key types
  btrfs: fix missing last_unlink_trans update when removing a directory
  btrfs: don't clobber errors in add_remap_tree_entries()
  btrfs: enable shutdown ioctl for non-experimental builds
  btrfs: apply first key check for readahead when possible
  btrfs: abort transaction in do_remap_reloc_trans() on failure
  btrfs: fix bytes_may_use leak in do_remap_reloc_trans()
  btrfs: fix bytes_may_use leak in move_existing_remap()
2026-04-27 16:35:44 -07:00
Mark Harmstone 82323b1a70 btrfs: fix double-decrement of bytes_may_use in submit_one_async_extent()
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 a4fe134fc1 ("btrfs: fix a double release on reserved
extents in cow_one_range()"), which is the same fix in cow_one_range().

Fixes: 151a41bc46 ("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>
2026-04-21 04:03:08 +02:00
robbieko a8d58a7c02 btrfs: check return value of btrfs_partially_delete_raid_extent()
btrfs_partially_delete_raid_extent() returns an error code (e.g.
-ENOMEM from kzalloc(), or errors from btrfs_del_item/btrfs_insert_item()),
but all three call sites in btrfs_delete_raid_extent() discard the
return value, silently losing errors and potentially leaving the stripe
tree in an inconsistent state.

Fix by capturing the return value into ret at all three call sites and
breaking out of the loop on error where appropriate.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: robbieko <robbieko@synology.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-04-21 04:02:39 +02:00
robbieko fe0cdfd711 btrfs: handle -EAGAIN from btrfs_duplicate_item and refresh stale leaf pointer
In the 'punch a hole' case of btrfs_delete_raid_extent(),
btrfs_duplicate_item() can return -EAGAIN when the leaf needs to be
split and the path becomes invalid. The old code treats any error as
fatal and breaks out of the loop.

Additionally, btrfs_duplicate_item() may trigger setup_leaf_for_split()
which can reallocate the leaf node. The code continues using the old
leaf pointer, leading to use-after-free or stale data access.

Fix both issues by:

- Handling -EAGAIN specifically: release the path and retry the loop.
- Refreshing leaf = path->nodes[0] after successful duplication.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: robbieko <robbieko@synology.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-04-21 04:02:34 +02:00
robbieko 653361585d btrfs: replace ASSERT with proper error handling in stripe lookup fallback
After falling back to the previous item in btrfs_delete_raid_extent(),
the code uses ASSERT(found_start <= start) to verify the found extent
actually precedes our target range. If the B-tree state is unexpected
(e.g. no overlapping extent exists), this triggers a kernel BUG/panic
in debug builds, or silently continues with wrong data otherwise.

Replace the ASSERT with a proper bounds check that returns -ENOENT if
the found extent does not actually overlap with the start position.

Signed-off-by: robbieko <robbieko@synology.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-04-21 04:02:30 +02:00
robbieko 1871ae78ff btrfs: fix wrong min_objectid in btrfs_previous_item() call
When found_start > start and slot == 0, btrfs_previous_item() is called
with min_objectid=start to find the previous stripe extent. However, the
previous stripe extent we are looking for has objectid < start (it starts
before our deletion range), so passing start as min_objectid prevents
finding it.

Fix by passing 0 as min_objectid to allow finding any preceding stripe
extent regardless of its objectid.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: robbieko <robbieko@synology.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-04-21 04:02:26 +02:00
robbieko 2aef5cb1dc btrfs: fix raid stripe search missing entries at leaf boundaries
In btrfs_delete_raid_extent(), the search key uses offset=0. When the
target stripe entry is the first item on a leaf, btrfs_search_slot()
may land on the previous leaf and decrementing the slot from nritems
still points to the wrong entry, causing the stripe extent to be
silently missed.

Fix this by searching with offset=(u64)-1 instead. Since no real stripe
entry has this offset, btrfs_search_slot() always returns 1 with the
slot pointing past the last matching objectid entry. Then unconditionally
decrement the slot with a proper slots[0]==0 early-exit check to handle
the case where no matching entry exists.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: robbieko <robbieko@synology.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-04-21 04:02:21 +02:00
robbieko 513f8a52ee btrfs: copy devid in btrfs_partially_delete_raid_extent()
When btrfs_partially_delete_raid_extent() rebuilds a truncated/shifted
stripe extent into newitem, the loop copies the physical address for
each stride but forgets to copy the devid. The resulting item written
back to the stripe tree has zeroed-out devids, corrupting the stripe
mapping.

Fix this by reading the devid with btrfs_raid_stride_devid() and
writing it into the new item with btrfs_set_stack_raid_stride_devid()
before copying the physical address.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: robbieko <robbieko@synology.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-04-21 04:02:18 +02:00
David Sterba 4d95b9efd7 btrfs: handle unexpected free-space-tree key types
Replace the conditional assertions with proper error handling and
transaction abort if we find an unexpected key type in the free space
tree.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-04-21 04:02:02 +02:00
Filipe Manana 999757231c btrfs: fix missing last_unlink_trans update when removing a directory
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>
2026-04-21 04:01:48 +02:00
Mark Harmstone 44366af740 btrfs: don't clobber errors in add_remap_tree_entries()
In add_remap_tree_entries(), we only process a certain number of entries
at a time, meaning we may need to loop.

But because we weren't checking the return value of btrfs_insert_empty_items()
within the loop, this meant that if the last iteration of the loop
succeeded but a previous iteration failed, we were erroneously returning
0.

Fix this by breaking the loop early if btrfs_insert_empty_items() fails.

Fixes: b56f35560b ("btrfs: handle setting up relocation of block group with remap-tree")
Signed-off-by: Mark Harmstone <mark@harmstone.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-04-21 04:01:43 +02:00
Qu Wenruo 41e706c07e btrfs: enable shutdown ioctl for non-experimental builds
Although commit 304076527c ("btrfs: move shutdown and remove_bdev
callbacks out of experimental features") tries to move both shutdown and
remove_bdev out of experimental features, that commit has only addressed
the super block operation callback, the ioctl one is left untouched.

Fix that missing aspect by also moving shutdown ioctl out of
experimental features.

Since we're here, also add unknown flag detection to reject any
unsupported shutdown flags.

Fixes: 304076527c ("btrfs: move shutdown and remove_bdev callbacks out of experimental features")
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-04-21 04:01:31 +02:00
Qu Wenruo a86a283430 btrfs: apply first key check for readahead when possible
Currently for tree block readahead we never pass a
btrfs_tree_parent_check with @has_first_key set.

Without @has_first_key set, btrfs will skip the following extra
checks:

- Header generation check
  This is a minor one.

- Empty leaf/node checks
  This is more serious, for certain trees like the csum tree, they are
  allowed to be empty, thus an empty leaf can pass the tree checker.
  But if there is a parent node for such an empty leaf, it indicates
  corruption.

  Without @has_first_key set, we can no longer detect such a problem.

  In fact there is already a fuzzed image report that a corrupted csum
  leaf which has zero nritems but still has a parent node can trigger
  a BUG_ON() during csum deletion.

However there are only two call sites of btrfs_readahead_tree_block():

- Inside relocate_tree_blocks()
  At this call site we are trying to grab the first key of the tree
  block, thus we are not able to pass a @first_key parameter.

- Inside btrfs_readahead_node_child()
  This is the more common call site, where we have the parent node and
  want to readahead the child tree blocks.

  In this case we can easily grab the node key and pass it for checks.

Add a new parameter @first_key to btrfs_readahead_tree_block() and pass
the node key to it inside btrfs_readahead_node_child().

This should plug the gap in empty leaf detection during readahead.

Link: https://lore.kernel.org/linux-btrfs/20260409071255.3358044-1-gality369@gmail.com/
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2026-04-21 04:01:24 +02:00