Teng Liu [Wed, 13 May 2026 11:35:44 +0000 (13:35 +0200)]
btrfs: validate data reloc tree file extent item members
get_new_location() uses BUG_ON() to crash the kernel if the file extent
item it looks up has any of offset, compression, encryption, or
other_encoding set non-zero. The data reloc inode is only written by
relocation's own paths and the four fields are always 0 in what the
kernel writes:
- insert_prealloc_file_extent() memsets the stack item to zero and
only fills in type, disk_bytenr, disk_num_bytes and num_bytes, so
offset/compression/encryption/other_encoding stay 0.
- insert_ordered_extent_file_extent() copies oe->compress_type into
the file extent's compression field, but the data reloc inode is
created with BTRFS_INODE_NOCOMPRESS so compress_type is always 0;
encryption and other_encoding are reserved-and-zero in btrfs.
A non-zero value here means the leaf decoded from disk does not match
what the kernel wrote, i.e. on-disk corruption. A malformed image
reaches this code via balance and panics the kernel.
A previous attempt to enforce all four constraints in tree-checker's
check_extent_data_item() was merged as commit 7d0ee95979e9 ("btrfs:
validate data reloc tree file extent item members in tree-checker")
and then reverted by commit 1c034697fcaa after btrfs/061 produced
false positives on arm64 with 64K pages. The reason: relocation
writeback legitimately produces REG file_extent_items with offset != 0
in the data reloc tree. When an ordered extent covers only the back
portion of an underlying PREALLOC (num_bytes < ram_bytes on the input
file_extent), insert_ordered_extent_file_extent() inserts a REG with
offset = oe->offset
num_bytes = oe->num_bytes
ram_bytes preserved from the original PREALLOC,
and this item can reach disk if a transaction commit fires while it
is present in the leaf.
The four fields belong in different layers:
- compression, encryption and other_encoding are universal
invariants for every item in the data reloc tree, regardless of
cluster geometry. Enforce them in tree-checker's
check_extent_data_item() so a corrupt leaf is rejected at read
time.
- offset is only an invariant at the cluster-boundary keys that
get_new_location() searches (the key is computed as
src_disk_bytenr - reloc_block_group_start). Partial-PREALLOC
writebacks legitimately place REG items at non-boundary keys with
offset != 0; tree-checker cannot reject these. The cluster-
boundary item is always written by either
insert_prealloc_file_extent() (offset=0 by memset) or by the
front portion of a partial writeback (offset=0 by construction),
so a non-zero offset there is corruption.
Enforce the universal invariants in check_extent_data_item() with a
file_extent_err() rejection. Convert the BUG_ON() in
get_new_location() to a -EUCLEAN return paired with btrfs_print_leaf()
and btrfs_err() so the offending leaf is logged. The caller in
replace_file_extents() already handles non-zero returns from
get_new_location() by breaking out of the loop without aborting the
transaction.
Suggested-by: Qu Wenruo <wqu@suse.com> Suggested-by: David Sterba <dsterba@suse.com> Reported-by: syzbot+3e20d8f3d41bac5dc9a2@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=3e20d8f3d41bac5dc9a2 Signed-off-by: Teng Liu <27rabbitlt@gmail.com> Signed-off-by: David Sterba <dsterba@suse.com>
btrfs: annotate lockless read of defrag_bytes in should_nocow()
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>
btrfs: zoned: always set max_active_zones for zoned devices
When a block device does not report a maximum number of open or active
zones, currently assign BTRFS_DEFAULT_MAX_ACTIVE_ZONES (128) to
the internal limit, if the device has more than
BTRFS_DEFAULT_MAX_ACTIVE_ZONES zones.
But if the device has less than BTRFS_DEFAULT_MAX_ACTIVE_ZONES the
internal max_active_zones limit will stay at 0, even if the device has
zone resource limits. Furthermore, if the device has a total number of
zones that is less than BTRFS_DEFAULT_MAX_ACTIVE_ZONE, max_active_zones
should be set to at most the number of zones.
Also move the max_active_zone calculation and setting into a dedicated
helper, to shrink btrfs_get_dev_zone_info().
Fixes: 04147d8394e8 ("btrfs: zoned: limit active zones to max_open_zones") Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
Revert "btrfs: fix the file offset calculation inside btrfs_decompress_buf2page()"
It seems that af566bdaff54 was tested against a tree which did not
contain commit 12851bd921d4 ("fs: Turn page_offset() into a wrapper
around folio_pos()). Unfortunately it has a bug of its own; on 32-bit
systems, shifting by PAGE_SHIFT will overflow on files larger than 4GiB.
Since page_offset() is now fixed, just revert af566bdaff54.
Fixes: af566bdaff54 (btrfs: fix the file offset calculation inside btrfs_decompress_buf2page()) Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Boris Burkov <boris@bur.io> Tested-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
btrfs: zoned: fix deadlock waiting for ticket during data relocation
When performing data relocation on a zoned filesystem, BTRFS can deadlock
in handle_reserve_tickets(). The relocation process is waiting on a space
reservation ticket that can never be fulfilled, because the relocation
itself is the operation responsible for freeing up that space.
Fix this by introducing a new flush state,
BTRFS_RESERVE_FLUSH_ZONED_RELOCATION, specifically for data chunk
allocation during zoned relocation. Like
BTRFS_RESERVE_FLUSH_FREE_SPACE_INODE, this state uses
priority_reclaim_data_space() instead of the normal flushing path, which
avoids re-entering the relocation code and breaking the deadlock cycle.
In btrfs_alloc_data_chunk_ondemand(), select this new flush state when the
inode belongs to a data relocation root on a zoned filesystem.
Fixes: e2a7fd22378f ("btrfs: zoned: add zone reclaim flush state for DATA space_info") Reviewed-by: Boris Burkov <boris@bur.io> Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
When searching for a data relocation block-group on mount,
btrfs_zoned_reserve_data_reloc_bg() is looking for the first empty DATA
block-group. But it first checks if the block-group is empty and if yes
continues the search, and then checks if it is the first DATA block-group.
There is actually no point in looking for the second empty DATA block
group as new DATA allocations will just allocate a new chunk for it. Pick
the first DATA block-group without any allocations done and set it as
relocation block-group.
At first, the commit 694ce5e143d6 ("btrfs: zoned: reserve data_reloc
block group on mount") introduced the functionality. At that time, we
took second unused (used == 0) block group, as the first one might be a
block group used for normal data. Later, commit daa0fde32235 ("btrfs:
zoned: fix data relocation block group reservation") switched to look
for an empty block group (alloc_offset == 0). At this point, there is no
reason taking the second one anymore. So, this commit is fixing an issue
in commit daa0fde32235.
Reviewed-by: Boris Burkov <boris@bur.io> Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
Qu Wenruo [Wed, 13 May 2026 04:36:21 +0000 (14:06 +0930)]
btrfs: introduce support for huge folios
With all the previous preparations, it's finally time to enable the
huge folio support.
- The max folio size
Here we define BTRFS_MAX_FOLIO_SIZE, which is fixed at 2MiB.
This will ensure we have a large enough but not too large folio for
btrfs. This limit applies to all systems regardless of page size.
Then we also define BTRFS_MAX_BLOCKS_PER_FOLIO, which depends on
CONFIG_BTRFS_EXPERIMENTAL.
If it's an experimental build, BTRFS_MAX_BLOCKS_PER_FOLIO is 512,
otherwise it's BITS_PER_LONG.
The filemap max order will be calculated using both
BTRFS_MAX_FOLIO_SIZE and BTRFS_MAX_BLOCKS_PER_FOLIO.
E.g. for 64K page size with 64K fs block size, the limit will be
BTRFS_MAX_FOLIO_SIZE (2M), which limits the filemap max order to 5.
This will be lower than the old order (6), but folios larger than 2M
are rarely any better for IO performance. Meanwhile excessively large
folios can cause other problems like stalling the IO pipeline for too
long.
For 4K page size and 4K fs block size, the limit will be increased to
2M from the old 256K.
This new size is constrained by both BTRFS_MAX_FOLIO_SIZE (2M) and
BTRFS_MAX_BLOCKS_PER_FOLIO (512 * 4K), allowing x86_64 to achieve huge
folio support, and the filemap max order will be 9.
- btrfs_bio_ctrl::submit_bitmap
This will be enlarged to contain BTRFS_MAX_BLOCKS_PER_FOLIO bits, and
this will be on-stack memory.
This will increase on-stack memory usage by 56 bytes compared to the
baseline (before the first patch in the series).
- Local @delalloc_bitmap inside writepage_delalloc()
Unfortunately we cannot afford to handle an allocation error here, thus
again we use on-stack memory.
Thus this will increase on-stack memory usage by 56 bytes again.
So unfortunately this means during the delalloc window, the writeback path
will have +112 bytes on-stack memory usage, and for other cases the
writeback path will have +56 bytes on-stack memory usage.
The +56 bytes (btrfs_bio_ctrl::submit_bitmap) can be removed
after we have reworked the compression submission, so the current
on-stack submit_bitmap is mostly a workaround until then.
Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Qu Wenruo [Wed, 13 May 2026 04:36:20 +0000 (14:06 +0930)]
btrfs: migrate btrfs_bio_ctrl::submit_bitmap to support larger bitmaps
[CURRENT LIMIT]
Btrfs currently only supports sub-bitmaps (e.g. dirty bitmap) no larger
than BITS_PER_LONG.
One call site that utilizes this limit is btrfs_bio_ctrl::submit_bitmap,
which makes it very simple and straightforward to just grab an unsigned
long value and assign it to submit_bitmap.
Unfortunately that limit prevents us from supporting huge folios.
For 4K page size and block size, a huge folio (order 9) means 512 blocks
inside a 2M folio.
[ENHANCEMENT]
Instead of using a fixed unsigned long value, change
btrfs_bio_ctrl::submit_bitmap to an unsigned long pointer.
And for cases where an unsigned long can hold the whole bitmap,
introduce @submit_bitmap_value, and just point that pointer to that
unsigned long.
Then update all direct users of bio_ctrl->submit_bitmap to use the
pointer version.
There are several call sites that get extra changes:
- @range_bitmap inside extent_writepage_io()
Which is only utilized to truncate the bitmap.
Since we do not want to allocate new memory just for such temporary
usage, change the original bitmap_set() and bitmap_and() into
bitmap_clear() for the ranges outside of the target range.
- Getting dirty subpage bitmap inside writepage_delalloc()
Since we're passing an unsigned long pointer now, we need to go with
different handling (bs == ps, blocks_per_folio <= BITS_PER_LONG,
blocks_per_folio > BITS_PER_LONG).
Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Qu Wenruo [Wed, 13 May 2026 04:36:19 +0000 (14:06 +0930)]
btrfs: prepare subpage operations to support more than BITS_PER_LONG sub-bitmaps
[CURRENT LIMIT]
Btrfs currently only supports sub-bitmaps (e.g. dirty bitmap) no larger
than BITS_PER_LONG.
That limit allows us to easily grab an unsigned long without the need to
properly allocate memory for a larger bitmap.
Unfortunately that limit prevents us from supporting huge folios.
For 4K page size and block size, a huge folio (order 9) means 512 blocks
inside a 2M folio.
[ENHANCEMENT]
To allow direct bitmap operations without allocating new memory,
introduce two different ways to access the subpage bitmaps:
- Return an unsigned long value
This only happens if blocks_per_folio <= BITS_PER_LONG.
We read out the sub-bitmap into an unsigned long, and return the
value.
This is the old existing method.
This involves get_bitmap_value_##name() helper functions.
And this time the helper functions are defined as inline functions
instead of macros to provide better type checks.
- Return a pointer where the sub-bitmap starts
This only happens if blocks_per_folio >= BITS_PER_LONG.
This is the new method for sub-bitmaps larger than BITS_PER_LONG.
Since the sizes of sub-bitmaps are all aligned to BITS_PER_LONG, we
can directly access the start word of the sub-bitmap.
This involves get_bitmap_pointer_##name() helper functions.
Then change the existing sub-bitmaps users to use the new helpers:
- Bitmap dumping
Switch between get_bitmap_value_##name() and
get_bitmap_pointer_##name() depending on the sub-bitmap size.
- btrfs_get_subpage_dirty_bitmap()
Rename it to btrfs_get_subpage_dirty_bitmap_value() to follow the new
value/pointer naming.
Since we do not support huge folios yet, there is no pointer version
for the dirty bitmap.
Furthermore, add the support for block size == page size cases for
btrfs_get_subpage_dirty_bitmap_value(), so that the caller no longer
needs to check if the folio needs subpage handling.
Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
David Sterba [Thu, 7 May 2026 17:59:32 +0000 (19:59 +0200)]
btrfs: simplify how first hit is passed to __btrfs_abort_transaction()
Optimize the btrfs_abort_transaction() for size as it (by our
convention) must be put right after the error condition is detected.
The exact file:line is reported so there's a portion that must be
inlined. As this is cold code it bloats functions. In previous patch
"btrfs: move transaction abort message to __btrfs_abort_transaction()"
the error message was moved to the common helper, saving like 20KiB of
btrfs.ko and several instructions per call site and some stack space.
There's little left to be optimized, we need to keep the atomic
test_and_set_bit() and to convey that as 'first hit' to
__btrfs_abort_transaction().
Right now it's a bool, which takes 8 bytes on stack for each call but
it's 1 bit of information. We can encode that to some of the other
parameters.
For that let's use the 'error' parameter, by convention it's negative
errno so we can reliably detect if it's the first hit or a later error.
Also the negation is usually implemented by a single instruction (NEG on
x86_64) so the resulting object code is kept short.
This reduces btrfs.ko by 8K and stack in several functions by 8 bytes.
Cumulative effect with the other commit is -30K of btrfs.ko. While the
encoding is an implementation detail, it's contained within the API.
Making the transaction abort calls very light is desired.
David Sterba [Thu, 7 May 2026 17:59:31 +0000 (19:59 +0200)]
btrfs: validate negative error number passed to btrfs_abort_transaction()
In preparation to encode more information to the error value add a step
that verifies if the value is valid (i.e. < 0). This works for
compile-time and runtime (in debugging mode).
The compile-time check recognizes direct constants and defines an array
type. An invalid condition leads to negative array size which is caught
by compiler.
The runtime check constructs the array type from the condition and only
verifies the correct size, as we don't need to tweak the size to be
negative.
The sizeof() expressions do not generate any code. In the debugging
config the warning adds about 9KiB of btrfs.ko code size.
The array size trick is needed as we can't use static_array(), not even
with __builtin_constant_p().
Sample error message:
In file included from inode.c:40:
inode.c: In function ‘__cow_file_range_inline’:
transaction.h:261:26: error: size of unnamed array is negative
261 | (void)sizeof(char[-!(__builtin_constant_p(error) ? (error) < 0 : 1)]); \
| ^
transaction.h:275:9: note: in expansion of macro ‘VERIFY_NEGATIVE_ERROR’
275 | VERIFY_NEGATIVE_ERROR(error); \
| ^~~~~~~~~~~~~~~~~~~~~
inode.c:665:17: note: in expansion of macro ‘btrfs_abort_transaction’
665 | btrfs_abort_transaction(trans, 17);
| ^~~~~~~~~~~~~~~~~~~~~~~
Filipe Manana [Thu, 21 May 2026 14:19:37 +0000 (15:19 +0100)]
btrfs: fix invalid pointer dereference in __btrfs_run_delayed_refs()
In the beginning of the loop, we try to obtain a locked delayed ref head,
if 'locked_ref' is currently NULL, by calling btrfs_select_ref_head(),
which can return an error pointer. If the error pointer is -EAGAIN we do
a continue and go back to the beginning of the loop, which will not try
again to call btrfs_select_ref_head() since 'locked_ref' is no longer
NULL but it's ERR_PTR(-EAGAIN), and then we do:
spin_lock(&locked_ref->lock);
against a ERR_PTR(-EAGAIN) value, generating an invalid pointer
dereference.
Fix this by ensuring that 'locked_ref' is set to NULL when
btrfs_select_ref_head() returns ERR_PTR(-EAGAIN) and incrementing 'count'
as well, to prevent infinite looping. We do this by doing a goto to the
bottom of the loop that already sets 'locked_ref' to NULL and does a
cond_resched(), with an increment to 'count' right before the goto.
These measures were in place before the refactoring in commit 0110a4c43451
("btrfs: refactor __btrfs_run_delayed_refs loop") but were unintentionally
lost afterwards.
Reported-by: Dan Carpenter <error27@gmail.com> Link: https://lore.kernel.org/linux-btrfs/ag8ARRwykv8bpJ87@stanley.mountain/ Fixes: 0110a4c43451 ("btrfs: refactor __btrfs_run_delayed_refs loop") Reviewed-by: Boris Burkov <boris@bur.io> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
KangNing Liao [Thu, 21 May 2026 12:29:45 +0000 (20:29 +0800)]
btrfs: protect sb_write_pointer() with invalidate lock
sb_write_pointer() reads the super block from the block device page cache
using read_cache_page_gfp(). This has the same race with BLKBSZSET as the
one fixed by commit 3f29d661e568 ("btrfs: sync read disk super and set
block size").
Take the mapping invalidate lock around read_cache_page_gfp() to
serialize the read against block size changes.
Filipe Manana [Thu, 14 May 2026 16:35:40 +0000 (17:35 +0100)]
btrfs: tracepoints: show inode type in btrfs_sync_file_enter() event
Print the type of the inode (directory, regular file, symlink, etc) to
facilitate debugging.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Thu, 14 May 2026 15:11:43 +0000 (16:11 +0100)]
btrfs: tracepoints: add trace event for btrfs_sync_log()
btrfs_sync_log() is one of the main functions called during a fsync.
Add trace events for when entering and exiting that function.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Mon, 11 May 2026 15:38:25 +0000 (16:38 +0100)]
btrfs: tracepoints: add trace event for btrfs_log_new_name()
btrfs_log_new_name() is an important function that affects inode logging
and is called during link and rename operations. Add trace events for when
entering and exiting that function.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Mon, 11 May 2026 15:13:18 +0000 (16:13 +0100)]
btrfs: tracepoints: add trace event for btrfs_record_new_subvolume()
btrfs_record_new_subvolume() is an important operation that affects
inode logging and is called during subvolume creation. Add a trace event
for it to help debug issues.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Mon, 11 May 2026 15:05:13 +0000 (16:05 +0100)]
btrfs: tracepoints: add trace event for btrfs_record_snapshot_destroy()
btrfs_record_snapshot_destroy() is an important operation that affects
inode logging and is called during subvolume/snapshot deletion as well as
during rmdir. Add a trace event for it to help debug issues.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Mon, 11 May 2026 14:51:13 +0000 (15:51 +0100)]
btrfs: tracepoints: add trace event for btrfs_record_unlink_dir()
btrfs_record_unlink_dir() is an important operation that affects inode
logging and is called during unlink and rename operations. Add a trace
event for it to help debug issues.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Fri, 8 May 2026 16:09:48 +0000 (17:09 +0100)]
btrfs: tracepoints: add trace event for log_new_delayed_dentries()
log_new_delayed_dentries() is an important step called during a fsync, as
well as during rename and link operations on inodes that were previously
logged. Add trace events for when entering and exiting that function.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Thu, 7 May 2026 12:05:16 +0000 (13:05 +0100)]
btrfs: use simple assertions where enough during inode logging and replay
In overwrite_item():
There's no point in printing the root's ID if the assertion fails, since
it can only be BTRFS_TREE_LOG_OBJECTID if it fails.
In log_new_delayed_dentries():
There's no point in using a verbose assertion to print the value of
ctx->logging_new_delayed_dentries because it's a boolean, so if the
assertion fails we know its value is true (1).
So convert them to simpler assertion to make the code less verbose.
It also slightly reduces the object size, at least on x86_64 using
Debian's gcc 14.2.0-19 (if CONFIG_BTRFS_ASSERT is enabled in the kernel
config, which is the case for SUSE distributions for example).
Before:
$ size fs/btrfs/btrfs.ko
text data bss dec hex filename 2028244 197176 15624 2241044 223214 fs/btrfs/btrfs.ko
After:
$ size fs/btrfs/btrfs.ko
text data bss dec hex filename 2028228 197176 15624 2241028 223204 fs/btrfs/btrfs.ko
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Thu, 7 May 2026 12:03:13 +0000 (13:03 +0100)]
btrfs: tracepoints: add trace event for log_conflicting_inodes()
log_conflicting_inodes() is an important step called during a fsync, as
well as during rename and link operations on inodes that were previously
logged. Add trace events for when entering and exiting that function.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Thu, 7 May 2026 10:17:55 +0000 (11:17 +0100)]
btrfs: tracepoints: add trace event for add_conflicting_inode()
add_conflicting_inode() is an important step called during a fsync, as
well as during rename and link operations on inodes that were previously
logged. Add trace events for when entering and exiting that function.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Tue, 5 May 2026 14:59:37 +0000 (15:59 +0100)]
btrfs: tracepoints: add trace event for log_new_dir_dentries()
log_new_dir_dentries() is an important step called during a fsync, as
well as during rename and link operations on inodes that were previously
logged. Add trace events for when entering and exiting that function.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Tue, 5 May 2026 14:31:16 +0000 (15:31 +0100)]
btrfs: tracepoints: add trace event for log_all_new_ancestors()
log_all_new_ancestors() is an important step called during a fsync, as
well as during rename and link operations on inodes that were previously
logged. Add trace events for when entering and exiting that function.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Thu, 30 Apr 2026 16:10:01 +0000 (17:10 +0100)]
btrfs: tracepoints: add trace event for btrfs_log_all_parents()
btrfs_log_all_parents() is an important step called during a fsync, as
well as during rename and link operations on inodes that were previously
logged. Add trace events for when entering and exiting that function.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Thu, 30 Apr 2026 15:05:56 +0000 (16:05 +0100)]
btrfs: tracepoints: add trace event for btrfs_log_inode()
btrfs_log_inode() is one of the most important steps called during a fsync,
as well as during rename and link operations on inodes that were previously
logged. Add trace events for when entering and exiting that function.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Wed, 29 Apr 2026 18:43:10 +0000 (19:43 +0100)]
btrfs: use a named enum for the log mode in inode log functions
We use this unnamed enum for the log mode and then pass it around log
functions as an int type with the odd name "inode_only" which suggests a
boolean. So add a name to the enum and change the type everywhere to that
enum and rename the parameters to something more clear - "log_mode".
Also move the enum into tree-log.h - it will be used later by new trace
events.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Tue, 28 Apr 2026 15:52:09 +0000 (16:52 +0100)]
btrfs: tracepoints: add trace event for btrfs_log_inode_parent()
btrfs_log_inode_parent() is one of the most important steps called during
a fsync operation as well as during rename and link operations on inodes
that were previously logged. Add trace events for when entering and
exiting that function.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Tue, 28 Apr 2026 14:32:15 +0000 (15:32 +0100)]
btrfs: tracepoints: add trace event for when fsync finishes
Currently we only have a trace event for when a fsync operation starts,
but this alone is not very helpful. Add a trace event for when fsync
finishes, which reports its return value, so that using tracing we can
see which other trace events happened in between (several will be added
soon for inode logging steps) and even measure execution time.
So rename the existing trace event btrfs_sync_file to
btrfs_sync_file_enter and add the trace event btrfs_sync_file_exit.
The naming is similar to what ext4 does (ext4_sync_file_enter and
ext4_sync_file_exit) and with similar information reported.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Mon, 27 Apr 2026 14:37:41 +0000 (15:37 +0100)]
btrfs: remove redundant writeback error check during fsync
If we can skip logging the inode during fsync, we check for writeback
errors in the inode's mapping by calling filemap_check_wb_err() and then
jump to the 'out_release_extents' label, which in turn jumps to the 'out'
label under which we check again for a writeback error by calling
file_check_and_advance_wb_err(). So the filemap_check_wb_err() ends up
being redundant. This happens since commit 333427a505be ("btrfs: minimal
conversion to errseq_t writeback error reporting on fsync").
Remove the filemap_check_wb_err() call.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Mon, 27 Apr 2026 10:42:35 +0000 (11:42 +0100)]
btrfs: stop checking for greater then zero return values in btrfs_sync_file()
The value of 'ret' can never be greater than zero when we reach the end of
btrfs_sync_file() but we have this ternary operator converting any such
value into -EIO. This logic exists since the first fsync implementation,
added in 2007 by commit 8fd17795b226 ("Btrfs: early fsync support"), when
all that fsync did was simply to commit a transaction, but even a call to
btrfs_commit_transaction() could never return a value greater than zero.
So stop checking for a greater than zero value and assert that 'ret' is
never greater than zero, to catch any eventual regression during future
development.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Thu, 23 Apr 2026 16:05:23 +0000 (17:05 +0100)]
btrfs: tracepoints: trace transaction states during commit phase
Currently the trace event is fired only when a transaction is fully
complete (its state is TRANS_STATE_COMPLETED). However during a
transaction commit we go through several states and as soon as the
state reaches TRANS_STATE_UNBLOCKED, another transaction can start.
Therefore it's useful to track every transaction state changed during
the commit of a transaction, so that we can see if a new transaction
is started before the current one is completed. Add the transaction
state to the transaction commit event and call the event everytime
we change the transaction state during commit.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Thu, 23 Apr 2026 14:56:52 +0000 (15:56 +0100)]
btrfs: tracepoints: add trace event for the start of a new transaction
While tracing it's useful to know not just when a transaction is committed
or aborted, but also when a new one is started. So add a trace event for
transaction starts.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Thu, 23 Apr 2026 14:17:16 +0000 (15:17 +0100)]
btrfs: tracepoints: add trace event for transaction aborts
While tracing it's useful to know not just when a transaction is committed
but also when one is aborted. So add a trace event for transaction aborts.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Fri, 17 Apr 2026 17:12:16 +0000 (18:12 +0100)]
btrfs: tracepoints: add in_fsync field to transaction commit event
Include the in_fsync value from the transaction handle so that we can know
if a transaction commit was triggered by a fsync call.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Fri, 17 Apr 2026 16:43:19 +0000 (17:43 +0100)]
btrfs: tracepoints: pass a transaction handle to transaction commit event
The transaction commit tracepoint prints fs_info->generation as if it
were the ID of the committed transaction but this does not always match
that ID. This is because the trace point is called in the transaction
commit path after the transaction is in the TRANS_STATE_COMPLETED state,
which means another transaction may have already started (which can happen
as soon as the transaction state was set to TRANS_STATE_UNBLOCKED), in
which case fs_info->generation was incremented and does not correspond
to the committed transaction anymore.
So fix this by passing a transaction handle to the trace event instead of
fs_info. This will also allow later for the trace event to dump other
useful information about the transaction.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Fri, 17 Apr 2026 16:38:45 +0000 (17:38 +0100)]
btrfs: remove call to transaction commit trace in btrfs_cleanup_transaction()
We are not committing a transaction there, plus in subsequent patches we
want to change the argument for the trace event to be a transaction handle
instead of fs_info and in this context we don't have a transaction handle
(struct btrfs_trans_handle, only a struct btrfs_transaction). So remove the
call to the trace point.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Fri, 17 Apr 2026 16:33:34 +0000 (17:33 +0100)]
btrfs: remove call to transaction commit trace in warn_about_uncommitted_trans()
We are not committing a transaction there, plus in subsequent patches we
want to change the argument for the trace event to be a transaction handle
instead of fs_info and in this context we don't have a transaction handle
(struct btrfs_trans_handle, only a struct btrfs_transaction). So remove the
call to the trace point.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Fri, 17 Apr 2026 16:22:59 +0000 (17:22 +0100)]
btrfs: tracepoints: remove pointless root field from transaction commit event
A transaction commit is global, not per root, and we are currently always
emitting a root id field matching the root tree for no good reason at all,
causing confusion for no reason at all. So remove the root field.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Fri, 17 Apr 2026 17:06:32 +0000 (18:06 +0100)]
btrfs: tracepoints: remove double negation in finish ordered extent event
There is no need to add a double negation (!!) to the update field because
the field has a boolean type.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Qu Wenruo [Mon, 11 May 2026 00:56:51 +0000 (10:26 +0930)]
btrfs: tree-checker: add more cross checks for free space tree
This introduces extra checks using the previous key.
If there is a previous key, we can do extra validations:
- The previous key is FREE_SPACE_INFO
This means the current extent/bitmap should be inside the
free space info key range.
And matches the type of the free space info.
- The previous key is FREE_SPACE_EXTENT or FREE_SPACE_BITMAP
In that case both the current and previous key should belong to the same
block group.
Thus the key type must match, and no overlap between the two keys.
These extra checks are inspired by the recently added type checks during
free space tree loading.
The new tree-checker checks will allow earlier detection, but the
loading time checks are still needed, as the tree-checker checks are
still inside the same leaf, not matching per-bg level checks.
Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Qu Wenruo [Tue, 12 May 2026 22:36:38 +0000 (08:06 +0930)]
btrfs: remove folio ordered flag and subpage bitmap
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>
Qu Wenruo [Thu, 7 May 2026 05:29:20 +0000 (14:59 +0930)]
btrfs: remove folio_test_ordered() usage
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>
Qu Wenruo [Thu, 7 May 2026 05:29:19 +0000 (14:59 +0930)]
btrfs: use dirty flag to check if an ordered extent needs to be truncated
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>
Qu Wenruo [Thu, 7 May 2026 05:29:18 +0000 (14:59 +0930)]
btrfs: unify folio dirty flag clearing
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>
Qu Wenruo [Thu, 7 May 2026 05:29:17 +0000 (14:59 +0930)]
btrfs: detect dirty blocks without an ordered extent more reliably
Currently btrfs detects dirty folio which doesn't have an ordered extent
at extent_writepage_io(), but that is not ideal:
- The check is not handling all dirty blocks
We can have multiple blocks inside a large folio, but the whole folio
is marked ordered as long as there is one ordered extent in the range.
We can still hit cases where some dirty blocks do not have
corresponding ordered extents.
Instead of checking the folio ordered flags, do the check at
alloc_new_bio(), where we're already searching for ordered extents for
writebacks.
If we didn't find an ordered extent, we should already give an error
message and notify the caller there is something wrong.
This allows us to check every block that goes through
submit_extent_folio().
With this new and more reliable check, we can remove the old check.
Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Qu Wenruo [Sat, 9 May 2026 09:06:31 +0000 (18:36 +0930)]
btrfs: remove locked subpage bitmap
Currently there are two members inside btrfs_folio_state that are related
to locked bitmap:
- locked sub-bitmap inside btrfs_folio_state::bitmaps[]
The enum btrfs_bitmap_nr_locked determines the sub-bitmap.
- btrfs_folio_state::nr_locked
Which records how many blocks are locked inside the folio.
The locked sub-bitmap is a btrfs specific per-block tracking mechanism,
which is mostly for async-submission, utilized by compressed writes.
The sub-bitmap itself is a super set of nr_locked, as it can provide a
more reliable tracking.
But the sub-bitmap itself can be pretty large for the incoming huge
folio, 2M sized folio for 4K page size, meaning 512 bits for one
sub-bitmap.
Furthermore, in the long run compression will be reworked to get rid of
async-submission completely, there is not much need for a full
sub-bitmap to track the locked status.
This patch removes the locked sub-bitmap and only relies on @nr_locked
atomic to do the tracking.
This can also save 64 bytes from btrfs_folio_state::bitmaps[] for a huge
folio.
This will reduce some safety checks, as previously if a block is not
locked, btrfs_folio_end_lock()/btrfs_folio_end_lock_bitmap() will find
out that, and skip reducing @nr_locked for that block, and avoid
under-flow.
But this safety net itself shouldn't be necessary in the first place.
If we're unlocking a block that is not locked, it's a bug in the logic,
and we should catch it, not silently ignoring it.
Thus I believe the removal of the extra safety net should not be a
problem.
Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Zhang Cen [Mon, 11 May 2026 07:01:28 +0000 (15:01 +0800)]
btrfs: tree-checker: validate names in ROOT_REF and ROOT_BACKREF
ROOT_REF and ROOT_BACKREF items contain a struct btrfs_root_ref followed
by the subvolume name. Several readers assume that this layout is already
valid and then use the on-disk name length directly. A corrupted item can
therefore make those readers address bytes outside the item, and
BTRFS_IOC_GET_SUBVOL_INFO can copy too many bytes into its fixed-size UAPI
name buffer.
Validate ROOT_REF and ROOT_BACKREF items in tree-checker before any reader
uses them. Reject records that do not contain a non-empty name, whose
name_len does not exactly describe the remaining item payload, or whose
name exceeds BTRFS_NAME_LEN.
For BTRFS_IOC_GET_SUBVOL_INFO, copy only the validated on-disk name_len
instead of deriving the copy length from the item size. The ioctl result is
zeroed when allocated. That leaves the existing trailing zero byte
untouched.
Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Zhang Cen <rollkingzzc@gmail.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Zhang Cen [Sun, 10 May 2026 15:03:22 +0000 (23:03 +0800)]
btrfs: free-space-tree: reject mismatched extent and bitmap items
btrfs_load_free_space_tree() reads FREE_SPACE_INFO once and then chooses
the bitmap or extent loader for all following free-space records until the
next FREE_SPACE_INFO item. Those loaders currently enforce the selected
record type only with ASSERT().
On production builds without CONFIG_BTRFS_ASSERT, a malformed free-space
tree can therefore be decoded in the wrong mode. An EXTENT item can reach
btrfs_free_space_test_bit() as bitmap data, while a BITMAP item can be
added as a full free extent. The latter corrupts the in-memory free-space
cache and the former can read beyond the item payload.
Validate every post-info key before decoding it. Reject keys whose type
does not match the mode selected by FREE_SPACE_INFO, and reject keys
whose range extends past the block group, returning -EUCLEAN instead of
feeding the wrong record type to the bitmap or extent decoder.
Also reject zero-length FREE_SPACE_EXTENT items in tree-checker, matching
the existing FREE_SPACE_BITMAP zero-length check. This keeps the loader
range check simple and prevents a zero-length extent item from being a
valid on-disk free-space record.
Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Zhang Cen <rollkingzzc@gmail.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
David Sterba [Thu, 30 Apr 2026 15:25:00 +0000 (17:25 +0200)]
btrfs: remove fs_info from struct btrfs_backref_iter
The fs_info is available everywhere and we don't need to store it inside
a structure that is used within one function only, which is
build_backref_tree(). The size of btrfs_backref_iter is now 48 bytes.
Qu Wenruo [Sun, 3 May 2026 09:47:50 +0000 (19:17 +0930)]
btrfs: unexport and move extent_invalidate_folio()
The function extent_invalidate_folio() has only a single caller inside
btree_invalidate_folio().
There is no need to export such a function just for a single caller inside
another file.
Unexport extent_invalidate_folio() and move it to disk-io.c.
And since we're moving the code, update the commit to match the current
style, and remove the seemingly stale comment on the extent state
removal, it's better explained by the comment just before
btrfs_unlock_extent().
Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Dave Chen [Mon, 4 May 2026 01:43:56 +0000 (09:43 +0800)]
btrfs: optimize fill_holes() to merge a new hole with both adjacent items
fill_holes() currently merges a punched hole with either the previous
or the next file extent item, but never both in the same call. When
holes are punched in a non-sequential order this leaves consecutive
hole items in the inode's subvolume tree that should have been collapsed
into a single one.
This is a minor metadata optimization that reduces the number of file
extent items when holes are punched in non-sequential order. While
having extra file extent items is harmless and has no functional
impact, reducing metadata overhead can benefit workloads with heavily
fragmented hole patterns.
After the third punch the [4K, 8K) and [12K, 16K) holes become
adjacent to the new [8K, 12K) hole, but fill_holes() merges only one
side and leaves two separate hole items ([4K, 12K) and [12K, 16K))
instead of the expected single [4K, 16K) hole item.
Fix this by checking both path->slots[0] - 1 and path->slots[0] in one
pass:
- If only the previous slot is mergeable, extend it forward as
before.
- If only the next slot is mergeable, extend it backward and update
its key offset as before.
- If both are mergeable, extend the previous item to cover the new
hole plus the next item, and remove the redundant next item with
btrfs_del_items().
Because the merge path may now delete an item, switch the initial
btrfs_search_slot() call from a plain lookup (ins_len = 0) to a
search-for-deletion (ins_len = -1), so the leaf is prepared for a
possible item removal.
Note: This optimization only applies to filesystems without the
NO_HOLES feature enabled. Since NO_HOLES is now the default, this
primarily benefits older filesystems or those explicitly created with
NO_HOLES disabled.
Signed-off-by: Dave Chen <davechen@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>
btrfs: warn about extent buffer that can not be released
When we unmount the fs or during mount failures, btrfs will call
invalidate_inode_pages() to release all btree inode folios.
However that function can return -EBUSY if any folios can not be
invalidated.
This can be caused by:
- Some extent buffers are still held by btrfs
This is a logic error, as we should release all tree root nodes
during unmount and mount failure handling.
- Some extent buffers are under readahead and haven't yet finished
These are much rarer but valid cases.
In that case we should wait for those extent buffers.
Introduce a new helper invalidate_and_check_btree_folios() which will:
- Call invalidate_inode_pages2() and catch its return value
If it returned 0 as expected, that's great and we can call it a day.
- Otherwise go through each extent buffer in buffer_tree
Increase the ref by one first for the eb we're checking.
This is to ensure the eb won't be freed after the readahead is
finished.
For ebs that still have EXTENT_BUFFER_READING flag, wait for them to
finish first.
After waiting for the readahead, check the refs of the eb and if it's
still dirty.
If the eb ref count is greater than 2 (one for the buffer tree, one
held by us), it means we are still holding the extent buffer somewhere
else, which is a code bug.
If the eb is still dirty, it means a bug in transaction handling, e.g.
the bug fixed by patch "btrfs: only release the dirty pages io tree
after successful writes".
For either case, show a warning message about the eb, including its
bytenr, owner, refs and flags.
And if it's a debug build, also trigger WARN_ON_ONCE() so that fstests
can properly catch such situation.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=221270 Reported-by: AHN SEOK-YOUNG <iamsyahn@gmail.com> CC: Teng Liu <27rabbitlt@gmail.com> Tested-by: Teng Liu <27rabbitlt@gmail.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Fri, 24 Apr 2026 15:08:57 +0000 (16:08 +0100)]
btrfs: make sure report_eb_range() is not inlined
If report_rb_range() is inlined into its single caller (check_eb_range()),
we end up with a larger module size, which is undesirable and does not
provide any advantage since this code is for a cold path which we don't
expect to ever hit.
Add the noinline attribute to report_rb_range() and while at it also make
it return void as it always returns true.
Before this change (with gcc 14.2.0-19 from Debian):
$ size fs/btrfs/btrfs.ko
text data bss dec hex filename 2018267 176232 15592 2210091 21b92b fs/btrfs/btrfs.ko
After this change:
$ size fs/btrfs/btrfs.ko
text data bss dec hex filename 2017835 176048 15592 2209475 21b6c3 fs/btrfs/btrfs.ko
Also, replacing the noinline with __cold, yields slighty worse results:
$ size fs/btrfs/btrfs.ko
text data bss dec hex filename 2017889 176048 15592 2209529 21b6f9 fs/btrfs/btrfs.ko
Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
David Sterba [Wed, 29 Apr 2026 14:32:53 +0000 (16:32 +0200)]
btrfs: move transaction abort message to __btrfs_abort_transaction()
The btrfs_abort_transaction() is called at the location where we want to
report the abort. It must be a macro so we get the correct line and
stack trace. This inlines the necessary code and the rest is pushed to
__btrfs_abort_transaction().
There's a possibility to reduce the inlined code if we move the message
to the helper function as well, without loss of information. The
difference is only that the WARN will not print it inside the stack
report but after:
--[ cut here ]--
WARNING: fs/btrfs/transaction.c:2045 at btrfs_commit_transaction+0xa21/0xd30 [btrfs], CPU#11: bonnie++/3377975
...
--[ end trace ] --
BTRFS error (device dm-0 state A): Transaction aborted (error -28)
While previously there would be one more line like:
--[ cut here ]--
BTRFS: Transaction aborted (error -28)
WARNING: fs/btrfs/transaction.c:2045 at btrfs_commit_transaction+0xa21/0xd30 [btrfs], CPU#11: bonnie++/3377975
...
--[ end trace ] --
This removes about 20KiB of btrfs.ko on a release config.
Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Mark Harmstone [Wed, 22 Apr 2026 14:03:35 +0000 (15:03 +0100)]
btrfs: don't force DIO writes to be serialized
Before btrfs switched to the new mount API in 2023, we were setting
SB_NOSEC in btrfs_mount_root(). This flag tells the VFS that the
filesystem may have files which don't have security xattrs, enabling it
to do some optimizations.
Unfortunately this was missed in the transition, meaning that IS_NOSEC
will always return false for a btrfs inode. This means that
btrfs_direct_write() calls will always get the inode lock exclusively,
meaning that DIO writes to the same file will be serialized.
On my machine, this one-line change results in a ~59% improvement in DIO
throughput:
This was on a VM with 8 cores and 8GB of RAM, with a real NVMe exposed
through PCI passthrough. The figures for XFS and ext4 in comparison are
both about ~3GB/s.
Fixes: ad21f15b0f79 ("btrfs: switch to the new mount API") Signed-off-by: Mark Harmstone <mark@harmstone.com> Signed-off-by: David Sterba <dsterba@suse.com>
btrfs: move large data folios out of experimental features
This feature was introduced in v6.17 under experimental, and we had
several small bugs related to or exposed by that:
e9e3b22ddfa7 ("btrfs: fix beyond-EOF write handling") 18de34daa7c6 ("btrfs: truncate ordered extent when skipping writeback past i_size")
Otherwise, the feature has been frequently tested by btrfs developers.
The latest fix only arrived in v6.19. After three releases, I think it's
time to move this feature out of experimental.
And since we're here, also remove the comment about the bitmap size
limit, which is no longer relevant in the context. It will soon be
outdated for the incoming huge folio support.
btrfs: refresh add_ra_bio_pages() to indicate it's using folios
The function add_ra_bio_folios() has been utilizing folio interfaces
since c808c1dcb1b2 ("btrfs: convert add_ra_bio_pages() to use only
folios"), but we are still referring to "pages" inside the function name
and all comments.
Furthermore, such folio/page mixing can even be confusing, e.g. the
variable @page_end is very confusing as we're not really referring to
the end of the page, but the end of the folio, especially when we
already have large folio support.
Enhance that function by:
- Rename "page" to "folio" to avoid confusion
- Skip to the folio end if there is already a folio in the page cache
The existing skip is:
cur += folio_size(folio);
This is incorrect if @cur is not folio size aligned, and can be
common with large folio support.
Thankfully this is not going to cause any real bugs, but at most will
skip some blocks that can be added to readahead.
Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
btrfs: enable cross-folio readahead for bs < ps and large folio cases
[BACKGROUND]
When bs < ps support was initially introduced, the compressed data
readahead was disabled as at that time the target page size was 64K.
This means a compressed data extent can span at most 3 64K pages (the
head and tail parts are not aligned to 64K), meaning the benefit is
pretty minimal.
[UNEXPECTED WORKING SITUATION]
But with the already merged large folio support, we're already enabling
readahead with subpage routine unintentionally, e.g.:
We have 2 8K sized folios, all backed by a single compressed data.
In that case add_ra_bio_pages() will continue to add folio 8K into the
read bio, as the condition to skip is only (bs < ps), not taking the
newer large folio support into consideration at all.
So for folio 8K, it is added to the read bio, but without subpage lock
bitmap populated.
Then at end_bbio_data_read(), folio 0 has proper locked bitmap set, but
folio 8K does not.
This inconsistency is handled by the extra safety net at
btrfs_subpage_end_and_test_lock() where if a folio has no @nr_locked, it
will just be unlocked without touching the locked bitmap.
[ENHANCEMENT]
Make add_ra_bio_pages() support bs < ps and large folio cases, by
removing the check and calling btrfs_folio_set_lock() unconditionally.
This won't make any difference on 4K page sized systems with large
folios, as the readahead is already working, although unexpectedly.
But this will enable true compressed data readahead for bs < ps cases
properly.
Please note that such readahead will only work if the compressed extent is
crossing folio boundaries, which is also the existing limitation.
Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
David Sterba [Tue, 14 Apr 2026 20:12:08 +0000 (22:12 +0200)]
btrfs: remove 32bit compat code for VFS inode number
Commit 0b2600f81cefcd ("treewide: change inode->i_ino from unsigned long
to u64") sets the inode number type to u64 unconditionally, so we can
use it directly as there's no difference on 32bit and 64bit platform. We
used to have a copy of the number in our btrfs_inode.
The size of btrfs_inode on 32bit platform is about 688 bytes (after the
change).
Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Jan Kara [Thu, 23 Apr 2026 09:30:53 +0000 (11:30 +0200)]
btrfs: limit size of bios submitted from writeback
Currently btrfs_writepages() just accumulates as large bio as possible
(within writeback_control constraints) and then submits it. This can
however lead to significant latency in writeback IO submission (I have
observed tens of milliseconds) because the submitted bio easily has over
hundred of megabytes. Consequently this leads to IO pipeline stalls and
reduced throughput.
At the same time beyond certain size submitting so large bio provides
diminishing returns because the bio is split by the block layer
immediately anyway. So compute (estimate of) bio size beyond which we
are unlikely to improve performance and just submit the bio for
writeback once we accumulate that much to keep the IO pipeline busy.
This improves writeback throughput for sequential writes by about 15% on
the test machine I was using.
Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Jan Kara <jack@suse.cz>
[ Fix the handling of missing device to avoid NULL pointer dereference. ] Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Originally 2K block size support was introduced to test subpage (block
size < page size) on x86_64 where the page size is exactly the original
minimal block size.
However that 2K block size support has some problems:
- No 2K nodesize support
This is critical, as there is still no way to exercise the subpage
metadata routine.
- Very easy to test subpage data path now
With the currently experimental large folio support, it's very easy to
test the subpage data folio path already, as when a folio larger than
4K is encountered on x86_64, we will need all the subpage folio states
and bitmaps.
So there is no need to use 2K block size just to verify subpage data
path even on x86_64.
And with the incoming huge folio (2M on x86_64) support, the 2K block
size will easily double the bitmap size, considering the burden to
maintain and the limited extra coverage, I believe it's time to remove
it for the incoming huge folio support.
Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Thu, 23 Apr 2026 14:01:20 +0000 (15:01 +0100)]
btrfs: change return type from int to bool in check_eb_range()
The function always returns true or false but the its return type is
defined as int, which makes no sense. Change it to bool.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> 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>
Filipe Manana [Thu, 23 Apr 2026 11:31:46 +0000 (12:31 +0100)]
btrfs: add missing unlikely to if branches leading to a DEBUG_WARN()
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>
Filipe Manana [Mon, 20 Apr 2026 10:44:07 +0000 (11:44 +0100)]
btrfs: use the enums instead of int type in struct btrfs_block_group fields
The 'disk_cache_state' and 'cached' fields are defined with an int type
but all the values we assigned to them come from the enums
btrfs_disk_cache_state and btrfs_caching_type. So change the type in the
btrfs_block_group structure from int to these enums - in practice an enum
is an int, so this is more for readability and clarity.
Reviewed-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Sun YangKai <sunk67188@gmail.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Mon, 20 Apr 2026 10:28:47 +0000 (11:28 +0100)]
btrfs: use min_size variable to setup block rsv in btrfs_replace_file_extents()
There's no need to calculate again the size for the temporary block
reserve in btrfs_replace_file_extents() - we have already calculated it
and stored it in the 'min_size' variable.
So use the variable to make it more clear and also make the variable const
since it's not supposed to change during the whole function.
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>
ZhengYuan Huang [Wed, 25 Mar 2026 00:43:38 +0000 (08:43 +0800)]
btrfs: balance: fix potential bg lookup failure in btrfs_may_alloc_data_chunk()
[BUG]
Running btrfs balance can trigger a null-ptr-deref before relocating a
data chunk when metadata corruption leaves a chunk in the chunk tree
without a corresponding block group in the in-memory cache:
[CAUSE]
__btrfs_balance() iterates the on-disk chunk tree and passes the chunk
logical bytenr to btrfs_may_alloc_data_chunk() before relocating a data
chunk. That helper then queries the in-memory block group cache:
cache = btrfs_lookup_block_group(fs_info, chunk_offset);
chunk_type = cache->flags; /* cache may be NULL */
A corrupt image can contain a chunk item whose matching block group
item is missing, so no block group is ever inserted into the cache. In
that case btrfs_lookup_block_group() returns NULL.
The code only guards this with ASSERT(cache), which becomes a no-op when
CONFIG_BTRFS_ASSERT is disabled. The subsequent dereference of
cache->flags therefore crashes the kernel.
[FIX]
Add a NULL check after btrfs_lookup_block_group() in
btrfs_may_alloc_data_chunk() and print and error message for clarity.
Signed-off-by: ZhengYuan Huang <gality369@gmail.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
ZhengYuan Huang [Wed, 25 Mar 2026 00:43:37 +0000 (08:43 +0800)]
btrfs: balance: fix potential bg lookup failure in chunk_usage_range_filter()
[BUG]
Running btrfs balance with a usage range filter (-dusage=min..max) can
trigger a null-ptr-deref when metadata corruption causes a chunk to have
no corresponding block group in the in-memory cache:
The bug is reproducible on recent development branch.
[CAUSE]
Two separate data structures are involved:
1. The on-disk chunk tree, which records every chunk (logical address
space region) and is iterated by __btrfs_balance().
2. The in-memory block group cache (fs_info->block_group_cache_tree),
which is built at mount time by btrfs_read_block_groups() and holds
a struct btrfs_block_group for each chunk. This cache is what the
usage range filter queries.
On a well-formed filesystem, these two are kept in 1:1 correspondence.
However, btrfs_read_block_groups() builds the cache from block group
items in the extent tree, not directly from the chunk tree. A corrupted
image can therefore contain a chunk item in the chunk tree whose
corresponding block group item is absent from the extent tree; that
chunk's block group is then never inserted into the in-memory cache.
When balance iterates the chunk tree and reaches such an orphaned chunk,
should_balance_chunk() calls chunk_usage_range_filter(), which queries
the block group cache:
cache = btrfs_lookup_block_group(fs_info, chunk_offset);
chunk_used = cache->used; /* cache may be NULL */
btrfs_lookup_block_group() returns NULL silently when no cached entry
covers chunk_offset. chunk_usage_range_filter() does not check the return
value, so the immediately following dereference of cache->used triggers
the crash.
[FIX]
Add a NULL check after btrfs_lookup_block_group() in
chunk_usage_range_filter(). When the lookup fails, emit a btrfs_err()
message identifying the affected bytenr and return -EUCLEAN to indicate
filesystem corruption.
Since chunk_usage_range_filter() now has an error path, change its
return type from bool to error pointer, return 0 if the chunk matches
the usage range, and 1 if it should be filtered out.
Signed-off-by: ZhengYuan Huang <gality369@gmail.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
ZhengYuan Huang [Wed, 25 Mar 2026 00:43:36 +0000 (08:43 +0800)]
btrfs: balance: fix potential bg lookup failure in chunk_usage_filter()
[BUG]
Running btrfs balance with a usage filter (-dusage=N) can trigger a
null-ptr-deref when metadata corruption causes a chunk to have no
corresponding block group in the in-memory cache:
The bug is reproducible on current development branch.
[CAUSE]
Two separate data structures are involved:
1. The on-disk chunk tree, which records every chunk (logical address
space region) and is iterated by __btrfs_balance().
2. The in-memory block group cache (fs_info->block_group_cache_tree),
which is built at mount time by btrfs_read_block_groups() and holds
a struct btrfs_block_group for each chunk. This cache is what the
usage filter queries.
On a well-formed filesystem, these two are kept in 1:1 correspondence.
However, btrfs_read_block_groups() builds the cache from block group
items in the extent tree, not directly from the chunk tree. A corrupted
image can therefore contain a chunk item in the chunk tree whose
corresponding block group item is absent from the extent tree; that
chunk's block group is then never inserted into the in-memory cache.
When balance iterates the chunk tree and reaches such an orphaned chunk,
should_balance_chunk() calls chunk_usage_filter(), which queries the block
group cache:
cache = btrfs_lookup_block_group(fs_info, chunk_offset);
chunk_used = cache->used; /* cache may be NULL */
btrfs_lookup_block_group() returns NULL silently when no cached entry
covers chunk_offset. chunk_usage_filter() does not check the return value,
so the immediately following dereference of cache->used triggers the crash.
[FIX]
Add a NULL check after btrfs_lookup_block_group() in chunk_usage_filter().
When the lookup fails, emit a btrfs_err() message identifying the
affected bytenr and return -EUCLEAN to indicate filesystem corruption.
Since chunk_usage_filter() now has an error path, change its return type
from bool to error pointer and 0 if the chunk passes the usage filter,
and 1 if it should be skipped.
Update should_balance_chunk() accordingly to propagate negative errors
from the usage filter.
Signed-off-by: ZhengYuan Huang <gality369@gmail.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Mark Harmstone [Thu, 16 Apr 2026 18:01:18 +0000 (19:01 +0100)]
btrfs: add ioctl GET_CSUMS to read raw checksums from file range
Add a new unprivileged BTRFS_IOC_GET_CSUMS ioctl, which can be used to
query the on-disk csums for a file range.
The ioctl is deliberately per-file rather than exposing raw csum tree
lookups, to avoid leaking information to users about files they may not
have access to.
This is done by userspace passing a struct btrfs_ioctl_get_csums_args to
the kernel, which details the offset and length we're interested in, and
a buffer for the kernel to write its results into. The kernel writes a
struct btrfs_ioctl_get_csums_entry into the buffer, followed by the
csums if available. The maximum size of the user buffer is capped to
16MiB.
If the extent is an uncompressed, non-NODATASUM extent, the kernel sets
the entry type to BTRFS_GET_CSUMS_HAS_CSUMS and follows it with the
csums. If it is sparse, preallocated, or beyond the EOF, it sets the
type to BTRFS_GET_CSUMS_ZEROED - this is so userspace knows it can use
the precomputed hash of the zero sector. Otherwise, it sets the type to
BTRFS_GET_CSUMS_NODATASUM, BTRFS_GET_CSUMS_COMPRESSED,
BTRFS_GET_CSUM_ENCRYPTED, or BTRFS_GET_CSUM_INLINE.
For example, a file with a [0, 4K) hole and [4K, 12K) data extent would
produce the following output buffer:
We do store the csums of compressed extents, but we deliberately don't
return them here: they're calculated over the compressed data, not the
uncompressed data that's returned to userspace. Similarly for encrypted
data, once encryption is supported, in which the csums will be on the
ciphertext.
The main use case for this is for speeding up mkfs.btrfs --rootdir. For
the case when the source FS is btrfs and using the same csum algorithm,
we can avoid having to recalculate the csums - in my synthetic
benchmarks (16GB file on a spinning-rust drive), this resulted in a ~11%
speed-up (218s to 196s).
When using the --reflink option added in btrfs-progs v6.16.1, we can forgo
reading the data entirely, resulting a ~2200% speed-up on the same test
(128s to 6s).
btrfs: check and set EXTENT_DELALLOC_NEW before clearing EXTENT_DELALLOC
[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():
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>
Filipe Manana [Wed, 15 Apr 2026 18:34:38 +0000 (19:34 +0100)]
btrfs: remove op field from struct btrfs_free_space_ctl
The op field always points to the same use_bitmap function, the only
exception is during self tests where we make it temporarily point to a
different function. So just because of this op pointer field we are
increasing the structure size by 8 bytes.
Instead of storing a pointer to a use_bitmap function in struct
btrfs_free_space_ctl, move the pointer to struct btrfs_info, make
insert_into_bitmap() use that pointer if we are running the self tests
and initialize that pointer to the current, default use_bitmap function
(now exported for the tests as btrfs_use_bitmap). This way we reduce
the size of struct btrfs_free_space_ctl from 136 to 128 bytes and can
now fit 32 structures in a 4K page instead of 30. This also avoids the
cost of the indirection of a function pointer call when we are not
running the self tests.
Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Wed, 15 Apr 2026 14:06:13 +0000 (15:06 +0100)]
btrfs: reduce size of struct btrfs_free_space_ctl
We have a 4 bytes hole in the structure, reorder some fields so that we
eliminate the hole and reduce the structure size from 144 bytes down to
136 bytes. This way on a 4K page system, we can fit 30 structures per
page instead of 28.
Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Wed, 15 Apr 2026 14:02:27 +0000 (15:02 +0100)]
btrfs: remove unit field from struct btrfs_free_space_ctl
The unit field always has a value matching the sector size, and since we
have a block group pointer in the structure, we can access the block group
and then its fs_info field to get to the sector size. So remove the field,
which will allow us later to shrink the structure size.
Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Wed, 15 Apr 2026 12:31:05 +0000 (13:31 +0100)]
btrfs: remove start field from struct btrfs_free_space_ctl
There's no need for the start field, we can take it from the block group.
This reduces the structure size from 152 bytes down to 144 bytes, so on
a 4K page system we can now fit 28 structures instead of 26.
Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Filipe Manana [Wed, 15 Apr 2026 12:12:13 +0000 (13:12 +0100)]
btrfs: use a kmem_cache for free space control structures
We are currently allocating the free space control structures for block
groups using the generic slabs, and given that the size of the
btrfs_free_space_ctl structure is 152 bytes (on a release kernel), we end
up using the kmalloc-192 slab and therefore waste quite some memory since
on a 4K page system we can only fit 21 free space control structures per
page. These structures are allocated and delallocated every time we create
and remove block groups.
So use a kmem_cache for free space control structures, this way on a 4K
page system we can fit 26 structures instead of 21.
Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Reorder some fields to eliminate the holes while keeping closely related
or frequently accessed fields together. After the reordering the size of
the structure is reduced down to 632 bytes and the number of cache lines
decreases from 11 to 10. We can still only pack 6 block groups per 4K page
but on a 64K page system we will now be able to pack 103 block groups
instead of 97. The new structure layout, on a release kernel, is the
following:
Filipe Manana [Wed, 15 Apr 2026 11:26:40 +0000 (12:26 +0100)]
btrfs: use a kmem_cache for block groups
We are currently allocating block groups using the generic slabs, and
given that the size of btrfs_block_group structure is 672 bytes (on a
release kernel), we end up using the kmalloc-1024 slab and therefore
waste quite some memory since on a 4K page system we can only fit 4
block groups per page. The block groups are also allocated and
delallocated with some frequency, specially if we have auto reclaim
enabled.
So use a kmem_cache for block groups, this way on a 4K page system we
can fit 6 block groups per page instead of 4.
Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
David Sterba [Tue, 31 Mar 2026 22:36:59 +0000 (00:36 +0200)]
btrfs: make more ASSERTs verbose, part 3
We have support for optional string to be printed in ASSERT() (added in 19468a623a9109 ("btrfs: enhance ASSERT() to take optional format
string")), it's not yet everywhere it could be so add a few more files.
Try to finish what was left after 1c094e6ccead7a ("btrfs: make a few
more ASSERTs verbose").
David Sterba [Tue, 14 Apr 2026 21:12:31 +0000 (23:12 +0200)]
btrfs: convert ioctl handlers to AUTO_KFREE
Many ioctl handlers are suitable for the AUTO_KFREE conversions as the
data are temporary and short lived. The conversions are trivial or the
collateral changes are straightforward.
A kfree() preceding mnt_drop_write_file() is slightly more efficient but
in the reverse order (i.e. the automatic kfree) does not cause any
significant change as the write drop does only a few simple operations.
Note: __free() handles also error pointers, so this is safe for the
memdup_user() errors too.
Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
David Sterba [Tue, 14 Apr 2026 15:30:34 +0000 (17:30 +0200)]
btrfs: convert kmalloc_array to kmalloc_objs in btrfs_calc_avail_data_space()
There's one use of kmalloc_array() that can be transformed to
kmalloc_objs() in the same way as suggested in commit 69050f8d6d075d
("treewide: Replace kmalloc with kmalloc_obj for non-scalar types"),
swap the arguments and drop GFP flags. All the other cases of
kmalloc_array() do not use a simple type so this is the only one.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
David Sterba [Tue, 14 Apr 2026 15:30:32 +0000 (17:30 +0200)]
btrfs: lift assertions to beginning of insert_delayed_ref()
There are only two possible types of the delayed ref action, this can be
verified at the beginning for the whole function and not just one block.
Replace the assertion with a debugging warning just in case.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
projects / thirdparty / kernel / linux.git / log
