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Merge tag 'for-6.15-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
- fix potential inode leak in iget() after memory allocation failure
- in subpage mode, fix extent buffer bitmap iteration when writing out
dirty sectors
- fix range calculation when falling back to COW for a NOCOW file
* tag 'for-6.15-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: adjust subpage bit start based on sectorsize
btrfs: fix the inode leak in btrfs_iget()
btrfs: fix COW handling in run_delalloc_nocow()
[BUG]
There is a bug report that a syzbot reproducer can lead to the following
busy inode at unmount time:
BTRFS info (device loop1): last unmount of filesystem 1680000e-3c1e-4c46-84b6-56bd3909af50
VFS: Busy inodes after unmount of loop1 (btrfs)
------------[ cut here ]------------
kernel BUG at fs/super.c:650!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 48168 Comm: syz-executor Not tainted 6.15.0-rc2-00471-g119009db2674 #2 PREEMPT(full)
Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:generic_shutdown_super+0x2e9/0x390 fs/super.c:650
Call Trace:
<TASK>
kill_anon_super+0x3a/0x60 fs/super.c:1237
btrfs_kill_super+0x3b/0x50 fs/btrfs/super.c:2099
deactivate_locked_super+0xbe/0x1a0 fs/super.c:473
deactivate_super fs/super.c:506 [inline]
deactivate_super+0xe2/0x100 fs/super.c:502
cleanup_mnt+0x21f/0x440 fs/namespace.c:1435
task_work_run+0x14d/0x240 kernel/task_work.c:227
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0x269/0x290 kernel/entry/common.c:218
do_syscall_64+0xd4/0x250 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
</TASK>
[CAUSE]
When btrfs_alloc_path() failed, btrfs_iget() directly returned without
releasing the inode already allocated by btrfs_iget_locked().
This results the above busy inode and trigger the kernel BUG.
[FIX]
Fix it by calling iget_failed() if btrfs_alloc_path() failed.
If we hit error inside btrfs_read_locked_inode(), it will properly call
iget_failed(), so nothing to worry about.
Although the iget_failed() cleanup inside btrfs_read_locked_inode() is a
break of the normal error handling scheme, let's fix the obvious bug
and backport first, then rework the error handling later.
Reported-by: Penglei Jiang <superman.xpt@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/20250421102425.44431-1-superman.xpt@gmail.com/
Fixes: 7c855e16ab ("btrfs: remove conditional path allocation in btrfs_read_locked_inode()")
CC: stable@vger.kernel.org # 6.13+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Penglei Jiang <superman.xpt@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In run_delalloc_nocow(), when the found btrfs_key's offset > cur_offset,
it indicates a gap between the current processing region and
the next file extent. The original code would directly jump to
the "must_cow" label, which increments the slot and forces a fallback
to COW. This behavior might skip an extent item and result in an
overestimated COW fallback range.
This patch modifies the logic so that when a gap is detected:
- If no COW range is already being recorded (cow_start is unset),
cow_start is set to cur_offset.
- cur_offset is then advanced to the beginning of the next extent.
- Instead of jumping to "must_cow", control flows directly to
"next_slot" so that the same extent item can be reexamined properly.
The change ensures that we accurately account for the extent gap and
avoid accidentally extending the range that needs to fallback to COW.
CC: stable@vger.kernel.org # 6.6+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Dave Chen <davechen@synology.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Merge tag 'for-6.15-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs updates from David Sterba:
"User visible changes:
- fall back to buffered write if direct io is done on a file that
requires checksums
- this avoids a problem with checksum mismatch errors, observed
e.g. on virtual images when writes to pages under writeback
cause the checksum mismatch reports
- this may lead to some performance degradation but currently the
recommended setup for VM images is to use the NOCOW file
attribute that also disables checksums
- fast/realtime zstd levels -15 to -1
- supported by mount options (compress=zstd:-5) and defrag ioctl
- improved speed, reduced compression ratio, check the commit for
sample measurements
- defrag ioctl extended to accept negative compression levels
- subpage mode
- remove warning when subpage mode is used, the feature is now
reasonably complete and tested
- in debug mode allow to create 2K b-tree nodes to allow testing
subpage on x86_64 with 4K pages too
Performance improvements:
- in send, better file path caching improves runtime (on sample load
by -30%)
- on s390x with hardware zlib support prepare the input buffer in a
better way to get the best results from the acceleration
- minor speed improvement in encoded read, avoid memory allocation in
synchronous mode
Core:
- enable stable writes on inodes, replacing manually waiting for
writeback and allowing to skip that on inodes without checksums
- add last checks and warnings for out-of-band dirty writes to pages,
requiring a fixup ("fixup worker"), this should not be necessary
since 5.8 where get_user_page() and pin_user_pages*() prevent this
- long history behind that, we'll be happy to remove the whole
infrastructure in the near future
- more folio API conversions and preparations for large folio support
- subpage cleanups and refactoring, split handling of data and
metadata to allow future support for large folios
- readpage works as block-by-block, no change for normal mode, this
is preparation for future subpage updates
- block group refcount fixes and hardening
- delayed iput fixes
- in zoned mode, fix zone activation on filesystem with missing
devices
Cleanups:
- inode parameter cleanups
- path auto-freeing updates
- code flow simplifications in send
- redundant parameter cleanups"
* tag 'for-6.15-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (164 commits)
btrfs: zoned: fix zone finishing with missing devices
btrfs: zoned: fix zone activation with missing devices
btrfs: remove end_no_trans label from btrfs_log_inode_parent()
btrfs: simplify condition for logging new dentries at btrfs_log_inode_parent()
btrfs: remove redundant else statement from btrfs_log_inode_parent()
btrfs: use memcmp_extent_buffer() at replay_one_extent()
btrfs: update outdated comment for overwrite_item()
btrfs: use variables to store extent buffer and slot at overwrite_item()
btrfs: avoid unnecessary memory allocation and copy at overwrite_item()
btrfs: don't clobber ret in btrfs_validate_super()
btrfs: prepare btrfs_page_mkwrite() for large folios
btrfs: prepare extent_io.c for future large folio support
btrfs: prepare btrfs_launcher_folio() for large folios support
btrfs: replace PAGE_SIZE with folio_size for subpage.[ch]
btrfs: add a size parameter to btrfs_alloc_subpage()
btrfs: subpage: make btrfs_is_subpage() check against a folio
btrfs: add extra warning if delayed iput is added when it's not allowed
btrfs: avoid redundant path slot assignment in btrfs_search_forward()
btrfs: remove unnecessary btrfs_key local variable in btrfs_search_forward()
btrfs: simplify the return value handling in search_ioctl()
...
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Merge tag 'vfs-6.15-rc1.async.dir' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs async dir updates from Christian Brauner:
"This contains cleanups that fell out of the work from async directory
handling:
- Change kern_path_locked() and user_path_locked_at() to never return
a negative dentry. This simplifies the usability of these helpers
in various places
- Drop d_exact_alias() from the remaining place in NFS where it is
still used. This also allows us to drop the d_exact_alias() helper
completely
- Drop an unnecessary call to fh_update() from nfsd_create_locked()
- Change i_op->mkdir() to return a struct dentry
Change vfs_mkdir() to return a dentry provided by the filesystems
which is hashed and positive. This allows us to reduce the number
of cases where the resulting dentry is not positive to very few
cases. The code in these places becomes simpler and easier to
understand.
- Repack DENTRY_* and LOOKUP_* flags"
* tag 'vfs-6.15-rc1.async.dir' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
doc: fix inline emphasis warning
VFS: Change vfs_mkdir() to return the dentry.
nfs: change mkdir inode_operation to return alternate dentry if needed.
fuse: return correct dentry for ->mkdir
ceph: return the correct dentry on mkdir
hostfs: store inode in dentry after mkdir if possible.
Change inode_operations.mkdir to return struct dentry *
nfsd: drop fh_update() from S_IFDIR branch of nfsd_create_locked()
nfs/vfs: discard d_exact_alias()
VFS: add common error checks to lookup_one_qstr_excl()
VFS: change kern_path_locked() and user_path_locked_at() to never return negative dentry
VFS: repack LOOKUP_ bit flags.
VFS: repack DENTRY_ flags.
That function is only calling btrfs_qgroup_free_data(), which doesn't
care about the size of the folio.
Just replace the fixed PAGE_SIZE with folio_size().
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
To support large data folios, we can no longer assume every filemap
folio is page sized.
So btrfs_is_subpage() check must be done against a folio.
Thankfully for metadata folios, we have the full control and ensure a
large folio will not be large than nodesize, so
btrfs_meta_is_subpage() doesn't need this change.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since I have triggered the ASSERT() on the delayed iput too many times,
now is the time to add some extra debug warnings for delayed iput.
All delayed iputs should be queued after all ordered extents finish
their IO and all involved workqueues are flushed.
Thus after the btrfs_run_delayed_iputs() inside close_ctree(), there
should be no more delayed puts added.
So introduce a new BTRFS_FS_STATE_NO_DELAYED_IPUT, set after the above
mentioned timing. And all btrfs_add_delayed_iput() will check that flag
and give a WARN_ON_ONCE().
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It's an internal function and btrfs_iget() is now returning a btrfs inode,
so change btrfs_iget_path() to also return a btrfs inode instead of a VFS
inode.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It's an internal function and most of the time the callers are doing a lot
of BTRFS_I() calls on the returned VFS inode to get the btrfs inode, so
change the return type to struct btrfs_inode instead.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The zstd and zlib compression types support setting compression levels.
Enhance the defrag interface to specify the levels as well. For zstd the
negative (realtime) levels are also accepted.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Daniel Vacek <neelx@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[OUT-OF-BAND DIRTY FOLIOS]
An out-of-band folio means the folio is marked dirty but without
notifying the filesystem.
This can lead to various problems, not limited to:
- No folio::private to track per block status
- No proper space reserved for such a dirty folio
[HISTORY IN BTRFS]
This used to be a problem related to get_user_page(), but with the
introduction of pin_user_pages*(), we should no longer hit such
case anymore.
In btrfs, we have a long history of catching such out-of-band dirty
folios by:
- Mark the folio ordered during delayed allocation
- Check the folio ordered flag during writeback
If the folio has no ordered flag, it means it doesn't go through
delayed allocation, thus it's definitely an out-of-band
one.
If we got one, we go through COW fixup, which will re-dirty the folio
with proper handling in another workqueue.
[PROBLEMS OF COW-FIXUP]
Such workaround is a blockage for us to migrate to iomap (it requires
extra flags to trace if a folio is dirtied by the fs or not) and I'd
argue it's not data checksum safe, since if a folio can be marked dirty
without informing the fs, the content can also change at any time.
But with the introduction of pin_user_pages*() during v5.8 merge
window, such out-of-band dirty folio such be treated as a bug.
Ext4 has treated such case by warning and erroring out even before
pin_user_pages*().
Furthermore, there are already proofs that such folio ordered flag
tracking can be screwed up by incorrect error handling, check the commit
messages of the following commits:
06f3642847 ("btrfs: do proper folio cleanup when cow_file_range() failed")
c2b47df81c ("btrfs: do proper folio cleanup when run_delalloc_nocow() failed")
[FIXES]
Unlike btrfs, ext4 and xfs (iomap) never bother handling such
out-of-band dirty folios.
- Ext4 just warns and errors out
- Iomap always follows the folio/block dirty flags
And there is nothing really COW specific, xfs also supports COW too.
Here we take one step towards ext4 by doing warning and erroring out.
But since the cow fixup thing is introduced from the beginning, we keep
the old behavior for non-experimental builds, and only do the new warning
for experimental builds before we're 100% sure and remove cow fixup.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Btrfs utilizes inline data extent for the following cases:
- Regular small files
- Symlinks
And "btrfs check" detects any file extents that are too large as an
error.
It's not a problem for 4K block size, but for the incoming smaller
block sizes (2K), it can cause problems due to bad limits:
- Non-compressed inline data extents
We do not allow a non-compressed inline data extent to be as large as
block size.
- Symlinks
Currently the only real limit on symlinks are 4K, which can be larger
than 2K block size.
These will result btrfs-check to report too large file extents.
Fix it by adding proper size checks for the above cases.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Previously inline data extents creation was disabled if the block size
(previously called sector size) is smaller than the page size, for the
following reasons:
- Possible mixed inline and regular data extents
However this is also the same if the block size matches the page size,
thus we do not treat mixed inline and regular extents as an error.
And the chance to cause mixed inline and regular data extents are not
even increased, it has the same requirement (compressed inline data
extent covering the whole first block, followed by regular extents).
- Inability to handle async/inline delalloc range for block size < page
size cases
This is already fixed since commit 1d2fbb7f1f ("btrfs: allow
compression even if the range is not page aligned").
This was the major technical obstacle, but it's not anymore.
With that removed, we can enable inline data extents creation no matter
the block size nor the page size, allowing btrfs to have the same
capacity for all block sizes.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Inside function __cow_file_range_inline() since the inlined data no
longer take any data space, we need to free up the reserved space.
However the code is still using the old page size == sector size
assumption, and will not handle subpage case well.
Thankfully it is not going to cause any problems because we have two extra
safe nets:
- Inline data extents creation is disabled for sector size < page size
cases for now
But it won't stay that for long.
- btrfs_qgroup_free_data() will only clear ranges which have been already
reserved
So even if we pass a range larger than what we need, it should still
be fine, especially there is only reserved space for a single block at
file offset 0 of an inline data extent.
But just for the sake of consistency, fix the call site to use
sectorsize instead of page size.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently reading an inline data extent will zero out the remaining
range in the page.
This is not yet causing problems even for block size < page size
(subpage) cases because:
1) An inline data extent always starts at file offset 0
Meaning at page read, we always read the inline extent first, before
any other blocks in the page. Then later blocks are properly read out
and re-fill the zeroed out ranges.
2) Currently btrfs will read out the whole page if a buffered write is
not page aligned
So a page is either fully uptodate at buffered write time (covers the
whole page), or we will read out the whole page first.
Meaning there is nothing to lose for such an inline extent read.
But it's still not ideal:
- We're zeroing out the page twice
Once done by read_inline_extent()/uncompress_inline(), once done by
btrfs_do_readpage() for ranges beyond i_size.
- We're touching blocks that don't belong to the inline extent
In the incoming patches, we can have a partial uptodate folio, of
which some dirty blocks can exist while the page is not fully uptodate:
The page size is 16K and block size is 4K:
0 4K 8K 12K 16K
| | |/////////| |
And range [8K, 12K) is dirtied by a buffered write, the remaining
blocks are not uptodate.
If range [0, 4K) contains an inline data extent, and we try to read
the whole page, the current behavior will overwrite range [8K, 12K)
with zero and cause data loss.
So to make the behavior more consistent and in preparation for future
changes, limit the inline data extents read to only zero out the range
inside the first block, not the whole page.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pass a struct btrfs_inode to btrfs_inherit_props() as it's an internal
interface, allowing to remove some use of BTRFS_I.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pass a struct btrfs_inode to btrfs_load_inode_props() as it's an
internal interface, allowing to remove some use of BTRFS_I.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pass a struct btrfs_inode to btrfs_fill_inode() as it's an internal
interface, allowing to remove some use of BTRFS_I.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pass a struct btrfs_inode to btrfs_inode() as it's an internal
interface, allowing to remove some use of BTRFS_I.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pass a struct btrfs_inode to new_simple_dir() as it's an internal
interface, allowing to remove some use of BTRFS_I.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pass a struct btrfs_inode to btrfs_inode() as it's an internal
interface, allowing to remove some use of BTRFS_I.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pass a struct btrfs_inode to btrfs_read_locked_inode() as it's an
internal interface, allowing to remove some use of BTRFS_I.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pass a struct btrfs_inode to extent_range_clear_dirty_for_io() as it's
an internal interface, allowing to remove some use of BTRFS_I.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pass a struct btrfs_inode to can_nocow_extent() as it's an internal
interface, allowing to remove some use of BTRFS_I.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The btrfs_key is defined as objectid/type/offset and the keys are also
printed like that. For better readability, update all key
initializations to match this order.
Signed-off-by: David Sterba <dsterba@suse.com>
The ordered extent cleanup is hard to grasp because it doesn't follow
the common cleanup-asap pattern.
E.g. run_delalloc_nocow() and cow_file_range() allocate one or more
ordered extent, but if any error is hit, the cleanup is done later inside
btrfs_run_delalloc_range().
To change the existing delayed cleanup:
- Update the comment on error handling of run_delalloc_nocow()
There are in fact 3 different cases other than 2 if we are doing
ordered extents cleanup inside run_delalloc_nocow():
1) @cow_start and @cow_end not set
No fallback to COW at all.
Before @cur_offset we need to cleanup the OE and page dirty.
After @cur_offset just clear all involved page and extent flags.
2) @cow_start set but @cow_end not set.
This means we failed before even calling fallback_to_cow().
It's just a variant of case 1), where it's @cow_start splitting
the two parts (and we should just ignore @cur_offset since it's
advanced without any new ordered extent).
3) @cow_start and @cow_end both set
This means fallback_to_cow() failed, meaning [start, cow_start)
needs the regular OE and dirty folio cleanup, and skip range
[cow_start, cow_end) as cow_file_range() has done the cleanup,
and eventually cleanup [cow_end, end) range.
- Only reset @cow_start after fallback_to_cow() succeeded
As above case 2) and 3) are both relying on @cow_start to determine
the cleanup range.
- Move btrfs_cleanup_ordered_extents() into run_delalloc_nocow(),
cow_file_range() and nocow_one_range()
For cow_file_range() it's pretty straightforward and easy.
For run_delalloc_nocow() refer to the above 3 different error cases.
For nocow_one_range() if we hit an error, we need to cleanup the
ordered extents by ourselves.
And then it will fallback to case 1), since @cur_offset is not yet
advanced, the existing cleanup will co-operate with nocow_one_range()
well.
- Remove the btrfs_cleanup_ordered_extents() inside submit_uncompressed_range()
As failed cow_file_range() will do all the proper cleanup now.
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently we're doing all the ordered extent and extent map generation
inside a while() loop of run_delalloc_nocow(). This makes it pretty
hard to read, nor doing proper error handling.
So move that part of code into a helper, nocow_one_range().
This should not change anything, but there is a tiny timing change where
btrfs_dec_nocow_writers() is only called after nocow_one_range() helper
exits.
This timing change is small, and makes error handling easier, thus
should be fine.
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The address space flag AS_STABLE_WRITES determine if FGP_STABLE for will
wait for the folio to finish its writeback.
For btrfs, due to the default data checksum behavior, if we modify the
folio while it's still under writeback, it will cause data checksum
mismatch. Thus for quite some call sites we manually call
folio_wait_writeback() to prevent such problem from happening.
Currently there is only one call site inside btrfs really utilizing
FGP_STABLE, and in that case we also manually call folio_wait_writeback()
to do the waiting.
But it's better to properly expose the stable writes flag to a per-inode
basis, to allow call sites to fully benefit from FGP_STABLE flag.
E.g. for inodes with NODATASUM allowing beginning dirtying the page
without waiting for writeback.
This involves:
- Update the mapping's stable write flag when setting/clearing NODATASUM
inode flag using ioctl
This only works for empty files, so it should be fine.
- Update the mapping's stable write flag when reading an inode from disk
- Remove the explicit folio_wait_writeback() for FGP_BEGINWRITE call
site
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Remove references to the page lock and page->mapping. Also btrfs folios
can never be swizzled into swap (mentioned in extent_write_cache_pages()).
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Only allocate the btrfs_encoded_read_private structure for asynchronous
(io_uring) mode.
There's no need to allocate an object from slab in the synchronous mode. In
such a case stack can be happily used as it used to be before 68d3b27e05
("btrfs: move priv off stack in btrfs_encoded_read_regular_fill_pages()")
which was a preparation for the async mode.
While at it, fix the comment to reflect the atomic => refcount change in
d29662695e ("btrfs: fix use-after-free waiting for encoded read endios").
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Daniel Vacek <neelx@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Merge tag 'for-6.14-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
- fix leaked extent map after error when reading chunks
- replace use of deprecated strncpy
- in zoned mode, fixed range when ulocking extent range, causing a hang
* tag 'for-6.14-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: fix a leaked chunk map issue in read_one_chunk()
btrfs: replace deprecated strncpy() with strscpy()
btrfs: zoned: fix extent range end unlock in cow_file_range()
Some filesystems, such as NFS, cifs, ceph, and fuse, do not have
complete control of sequencing on the actual filesystem (e.g. on a
different server) and may find that the inode created for a mkdir
request already exists in the icache and dcache by the time the mkdir
request returns. For example, if the filesystem is mounted twice the
directory could be visible on the other mount before it is on the
original mount, and a pair of name_to_handle_at(), open_by_handle_at()
calls could instantiate the directory inode with an IS_ROOT() dentry
before the first mkdir returns.
This means that the dentry passed to ->mkdir() may not be the one that
is associated with the inode after the ->mkdir() completes. Some
callers need to interact with the inode after the ->mkdir completes and
they currently need to perform a lookup in the (rare) case that the
dentry is no longer hashed.
This lookup-after-mkdir requires that the directory remains locked to
avoid races. Planned future patches to lock the dentry rather than the
directory will mean that this lookup cannot be performed atomically with
the mkdir.
To remove this barrier, this patch changes ->mkdir to return the
resulting dentry if it is different from the one passed in.
Possible returns are:
NULL - the directory was created and no other dentry was used
ERR_PTR() - an error occurred
non-NULL - this other dentry was spliced in
This patch only changes file-systems to return "ERR_PTR(err)" instead of
"err" or equivalent transformations. Subsequent patches will make
further changes to some file-systems to return a correct dentry.
Not all filesystems reliably result in a positive hashed dentry:
- NFS, cifs, hostfs will sometimes need to perform a lookup of
the name to get inode information. Races could result in this
returning something different. Note that this lookup is
non-atomic which is what we are trying to avoid. Placing the
lookup in filesystem code means it only happens when the filesystem
has no other option.
- kernfs and tracefs leave the dentry negative and the ->revalidate
operation ensures that lookup will be called to correctly populate
the dentry. This could be fixed but I don't think it is important
to any of the users of vfs_mkdir() which look at the dentry.
The recommendation to use
d_drop();d_splice_alias()
is ugly but fits with current practice. A planned future patch will
change this.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: NeilBrown <neilb@suse.de>
Link: https://lore.kernel.org/r/20250227013949.536172-2-neilb@suse.de
Signed-off-by: Christian Brauner <brauner@kernel.org>
Running generic/751 on the for-next branch often results in a hang like
below. They are both stack by locking an extent. This suggests someone
forget to unlock an extent.
INFO: task kworker/u128:1:12 blocked for more than 323 seconds.
Not tainted 6.13.0-BTRFS-ZNS+ #503
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u128:1 state:D stack:0 pid:12 tgid:12 ppid:2 flags:0x00004000
Workqueue: btrfs-fixup btrfs_work_helper [btrfs]
Call Trace:
<TASK>
__schedule+0x534/0xdd0
schedule+0x39/0x140
__lock_extent+0x31b/0x380 [btrfs]
? __pfx_autoremove_wake_function+0x10/0x10
btrfs_writepage_fixup_worker+0xf1/0x3a0 [btrfs]
btrfs_work_helper+0xff/0x480 [btrfs]
? lock_release+0x178/0x2c0
process_one_work+0x1ee/0x570
? srso_return_thunk+0x5/0x5f
worker_thread+0x1d1/0x3b0
? __pfx_worker_thread+0x10/0x10
kthread+0x10b/0x230
? __pfx_kthread+0x10/0x10
ret_from_fork+0x30/0x50
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1a/0x30
</TASK>
INFO: task kworker/u134:0:184 blocked for more than 323 seconds.
Not tainted 6.13.0-BTRFS-ZNS+ #503
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u134:0 state:D stack:0 pid:184 tgid:184 ppid:2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-btrfs-4)
Call Trace:
<TASK>
__schedule+0x534/0xdd0
schedule+0x39/0x140
__lock_extent+0x31b/0x380 [btrfs]
? __pfx_autoremove_wake_function+0x10/0x10
find_lock_delalloc_range+0xdb/0x260 [btrfs]
writepage_delalloc+0x12f/0x500 [btrfs]
? srso_return_thunk+0x5/0x5f
extent_write_cache_pages+0x232/0x840 [btrfs]
btrfs_writepages+0x72/0x130 [btrfs]
do_writepages+0xe7/0x260
? srso_return_thunk+0x5/0x5f
? lock_acquire+0xd2/0x300
? srso_return_thunk+0x5/0x5f
? find_held_lock+0x2b/0x80
? wbc_attach_and_unlock_inode.part.0+0x102/0x250
? wbc_attach_and_unlock_inode.part.0+0x102/0x250
__writeback_single_inode+0x5c/0x4b0
writeback_sb_inodes+0x22d/0x550
__writeback_inodes_wb+0x4c/0xe0
wb_writeback+0x2f6/0x3f0
wb_workfn+0x32a/0x510
process_one_work+0x1ee/0x570
? srso_return_thunk+0x5/0x5f
worker_thread+0x1d1/0x3b0
? __pfx_worker_thread+0x10/0x10
kthread+0x10b/0x230
? __pfx_kthread+0x10/0x10
ret_from_fork+0x30/0x50
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1a/0x30
</TASK>
This happens because we have another success path for the zoned mode. When
there is no active zone available, btrfs_reserve_extent() returns
-EAGAIN. In this case, we have two reactions.
(1) If the given range is never allocated, we can only wait for someone
to finish a zone, so wait on BTRFS_FS_NEED_ZONE_FINISH bit and retry
afterward.
(2) Or, if some allocations are already done, we must bail out and let
the caller to send IOs for the allocation. This is because these IOs
may be necessary to finish a zone.
The commit 06f3642847 ("btrfs: do proper folio cleanup when
cow_file_range() failed") moved the unlock code from the inside of the
loop to the outside. So, previously, the allocated extents are unlocked
just after the allocation and so before returning from the function.
However, they are no longer unlocked on the case (2) above. That caused
the hang issue.
Fix the issue by modifying the 'end' to the end of the allocated
range. Then, we can exit the loop and the same unlock code can properly
handle the case.
Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Fixes: 06f3642847 ("btrfs: do proper folio cleanup when cow_file_range() failed")
CC: stable@vger.kernel.org
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
indivudual patches which are described in their changelogs.
- "Allocate and free frozen pages" from Matthew Wilcox reorganizes the
page allocator so we end up with the ability to allocate and free
zero-refcount pages. So that callers (ie, slab) can avoid a refcount
inc & dec.
- "Support large folios for tmpfs" from Baolin Wang teaches tmpfs to use
large folios other than PMD-sized ones.
- "Fix mm/rodata_test" from Petr Tesarik performs some maintenance and
fixes for this small built-in kernel selftest.
- "mas_anode_descend() related cleanup" from Wei Yang tidies up part of
the mapletree code.
- "mm: fix format issues and param types" from Keren Sun implements a
few minor code cleanups.
- "simplify split calculation" from Wei Yang provides a few fixes and a
test for the mapletree code.
- "mm/vma: make more mmap logic userland testable" from Lorenzo Stoakes
continues the work of moving vma-related code into the (relatively) new
mm/vma.c.
- "mm/page_alloc: gfp flags cleanups for alloc_contig_*()" from David
Hildenbrand cleans up and rationalizes handling of gfp flags in the page
allocator.
- "readahead: Reintroduce fix for improper RA window sizing" from Jan
Kara is a second attempt at fixing a readahead window sizing issue. It
should reduce the amount of unnecessary reading.
- "synchronously scan and reclaim empty user PTE pages" from Qi Zheng
addresses an issue where "huge" amounts of pte pagetables are
accumulated
(https://lore.kernel.org/lkml/cover.1718267194.git.zhengqi.arch@bytedance.com/).
Qi's series addresses this windup by synchronously freeing PTE memory
within the context of madvise(MADV_DONTNEED).
- "selftest/mm: Remove warnings found by adding compiler flags" from
Muhammad Usama Anjum fixes some build warnings in the selftests code
when optional compiler warnings are enabled.
- "mm: don't use __GFP_HARDWALL when migrating remote pages" from David
Hildenbrand tightens the allocator's observance of __GFP_HARDWALL.
- "pkeys kselftests improvements" from Kevin Brodsky implements various
fixes and cleanups in the MM selftests code, mainly pertaining to the
pkeys tests.
- "mm/damon: add sample modules" from SeongJae Park enhances DAMON to
estimate application working set size.
- "memcg/hugetlb: Rework memcg hugetlb charging" from Joshua Hahn
provides some cleanups to memcg's hugetlb charging logic.
- "mm/swap_cgroup: remove global swap cgroup lock" from Kairui Song
removes the global swap cgroup lock. A speedup of 10% for a tmpfs-based
kernel build was demonstrated.
- "zram: split page type read/write handling" from Sergey Senozhatsky
has several fixes and cleaups for zram in the area of zram_write_page().
A watchdog softlockup warning was eliminated.
- "move pagetable_*_dtor() to __tlb_remove_table()" from Kevin Brodsky
cleans up the pagetable destructor implementations. A rare
use-after-free race is fixed.
- "mm/debug: introduce and use VM_WARN_ON_VMG()" from Lorenzo Stoakes
simplifies and cleans up the debugging code in the VMA merging logic.
- "Account page tables at all levels" from Kevin Brodsky cleans up and
regularizes the pagetable ctor/dtor handling. This results in
improvements in accounting accuracy.
- "mm/damon: replace most damon_callback usages in sysfs with new core
functions" from SeongJae Park cleans up and generalizes DAMON's sysfs
file interface logic.
- "mm/damon: enable page level properties based monitoring" from
SeongJae Park increases the amount of information which is presented in
response to DAMOS actions.
- "mm/damon: remove DAMON debugfs interface" from SeongJae Park removes
DAMON's long-deprecated debugfs interfaces. Thus the migration to sysfs
is completed.
- "mm/hugetlb: Refactor hugetlb allocation resv accounting" from Peter
Xu cleans up and generalizes the hugetlb reservation accounting.
- "mm: alloc_pages_bulk: small API refactor" from Luiz Capitulino
removes a never-used feature of the alloc_pages_bulk() interface.
- "mm/damon: extend DAMOS filters for inclusion" from SeongJae Park
extends DAMOS filters to support not only exclusion (rejecting), but
also inclusion (allowing) behavior.
- "Add zpdesc memory descriptor for zswap.zpool" from Alex Shi
"introduces a new memory descriptor for zswap.zpool that currently
overlaps with struct page for now. This is part of the effort to reduce
the size of struct page and to enable dynamic allocation of memory
descriptors."
- "mm, swap: rework of swap allocator locks" from Kairui Song redoes and
simplifies the swap allocator locking. A speedup of 400% was
demonstrated for one workload. As was a 35% reduction for kernel build
time with swap-on-zram.
- "mm: update mips to use do_mmap(), make mmap_region() internal" from
Lorenzo Stoakes reworks MIPS's use of mmap_region() so that
mmap_region() can be made MM-internal.
- "mm/mglru: performance optimizations" from Yu Zhao fixes a few MGLRU
regressions and otherwise improves MGLRU performance.
- "Docs/mm/damon: add tuning guide and misc updates" from SeongJae Park
updates DAMON documentation.
- "Cleanup for memfd_create()" from Isaac Manjarres does that thing.
- "mm: hugetlb+THP folio and migration cleanups" from David Hildenbrand
provides various cleanups in the areas of hugetlb folios, THP folios and
migration.
- "Uncached buffered IO" from Jens Axboe implements the new
RWF_DONTCACHE flag which provides synchronous dropbehind for pagecache
reading and writing. To permite userspace to address issues with
massive buildup of useless pagecache when reading/writing fast devices.
- "selftests/mm: virtual_address_range: Reduce memory" from Thomas
Weißschuh fixes and optimizes some of the MM selftests.
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Merge tag 'mm-stable-2025-01-26-14-59' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
"The various patchsets are summarized below. Plus of course many
indivudual patches which are described in their changelogs.
- "Allocate and free frozen pages" from Matthew Wilcox reorganizes
the page allocator so we end up with the ability to allocate and
free zero-refcount pages. So that callers (ie, slab) can avoid a
refcount inc & dec
- "Support large folios for tmpfs" from Baolin Wang teaches tmpfs to
use large folios other than PMD-sized ones
- "Fix mm/rodata_test" from Petr Tesarik performs some maintenance
and fixes for this small built-in kernel selftest
- "mas_anode_descend() related cleanup" from Wei Yang tidies up part
of the mapletree code
- "mm: fix format issues and param types" from Keren Sun implements a
few minor code cleanups
- "simplify split calculation" from Wei Yang provides a few fixes and
a test for the mapletree code
- "mm/vma: make more mmap logic userland testable" from Lorenzo
Stoakes continues the work of moving vma-related code into the
(relatively) new mm/vma.c
- "mm/page_alloc: gfp flags cleanups for alloc_contig_*()" from David
Hildenbrand cleans up and rationalizes handling of gfp flags in the
page allocator
- "readahead: Reintroduce fix for improper RA window sizing" from Jan
Kara is a second attempt at fixing a readahead window sizing issue.
It should reduce the amount of unnecessary reading
- "synchronously scan and reclaim empty user PTE pages" from Qi Zheng
addresses an issue where "huge" amounts of pte pagetables are
accumulated:
https://lore.kernel.org/lkml/cover.1718267194.git.zhengqi.arch@bytedance.com/
Qi's series addresses this windup by synchronously freeing PTE
memory within the context of madvise(MADV_DONTNEED)
- "selftest/mm: Remove warnings found by adding compiler flags" from
Muhammad Usama Anjum fixes some build warnings in the selftests
code when optional compiler warnings are enabled
- "mm: don't use __GFP_HARDWALL when migrating remote pages" from
David Hildenbrand tightens the allocator's observance of
__GFP_HARDWALL
- "pkeys kselftests improvements" from Kevin Brodsky implements
various fixes and cleanups in the MM selftests code, mainly
pertaining to the pkeys tests
- "mm/damon: add sample modules" from SeongJae Park enhances DAMON to
estimate application working set size
- "memcg/hugetlb: Rework memcg hugetlb charging" from Joshua Hahn
provides some cleanups to memcg's hugetlb charging logic
- "mm/swap_cgroup: remove global swap cgroup lock" from Kairui Song
removes the global swap cgroup lock. A speedup of 10% for a
tmpfs-based kernel build was demonstrated
- "zram: split page type read/write handling" from Sergey Senozhatsky
has several fixes and cleaups for zram in the area of
zram_write_page(). A watchdog softlockup warning was eliminated
- "move pagetable_*_dtor() to __tlb_remove_table()" from Kevin
Brodsky cleans up the pagetable destructor implementations. A rare
use-after-free race is fixed
- "mm/debug: introduce and use VM_WARN_ON_VMG()" from Lorenzo Stoakes
simplifies and cleans up the debugging code in the VMA merging
logic
- "Account page tables at all levels" from Kevin Brodsky cleans up
and regularizes the pagetable ctor/dtor handling. This results in
improvements in accounting accuracy
- "mm/damon: replace most damon_callback usages in sysfs with new
core functions" from SeongJae Park cleans up and generalizes
DAMON's sysfs file interface logic
- "mm/damon: enable page level properties based monitoring" from
SeongJae Park increases the amount of information which is
presented in response to DAMOS actions
- "mm/damon: remove DAMON debugfs interface" from SeongJae Park
removes DAMON's long-deprecated debugfs interfaces. Thus the
migration to sysfs is completed
- "mm/hugetlb: Refactor hugetlb allocation resv accounting" from
Peter Xu cleans up and generalizes the hugetlb reservation
accounting
- "mm: alloc_pages_bulk: small API refactor" from Luiz Capitulino
removes a never-used feature of the alloc_pages_bulk() interface
- "mm/damon: extend DAMOS filters for inclusion" from SeongJae Park
extends DAMOS filters to support not only exclusion (rejecting),
but also inclusion (allowing) behavior
- "Add zpdesc memory descriptor for zswap.zpool" from Alex Shi
introduces a new memory descriptor for zswap.zpool that currently
overlaps with struct page for now. This is part of the effort to
reduce the size of struct page and to enable dynamic allocation of
memory descriptors
- "mm, swap: rework of swap allocator locks" from Kairui Song redoes
and simplifies the swap allocator locking. A speedup of 400% was
demonstrated for one workload. As was a 35% reduction for kernel
build time with swap-on-zram
- "mm: update mips to use do_mmap(), make mmap_region() internal"
from Lorenzo Stoakes reworks MIPS's use of mmap_region() so that
mmap_region() can be made MM-internal
- "mm/mglru: performance optimizations" from Yu Zhao fixes a few
MGLRU regressions and otherwise improves MGLRU performance
- "Docs/mm/damon: add tuning guide and misc updates" from SeongJae
Park updates DAMON documentation
- "Cleanup for memfd_create()" from Isaac Manjarres does that thing
- "mm: hugetlb+THP folio and migration cleanups" from David
Hildenbrand provides various cleanups in the areas of hugetlb
folios, THP folios and migration
- "Uncached buffered IO" from Jens Axboe implements the new
RWF_DONTCACHE flag which provides synchronous dropbehind for
pagecache reading and writing. To permite userspace to address
issues with massive buildup of useless pagecache when
reading/writing fast devices
- "selftests/mm: virtual_address_range: Reduce memory" from Thomas
Weißschuh fixes and optimizes some of the MM selftests"
* tag 'mm-stable-2025-01-26-14-59' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits)
mm/compaction: fix UBSAN shift-out-of-bounds warning
s390/mm: add missing ctor/dtor on page table upgrade
kasan: sw_tags: use str_on_off() helper in kasan_init_sw_tags()
tools: add VM_WARN_ON_VMG definition
mm/damon/core: use str_high_low() helper in damos_wmark_wait_us()
seqlock: add missing parameter documentation for raw_seqcount_try_begin()
mm/page-writeback: consolidate wb_thresh bumping logic into __wb_calc_thresh
mm/page_alloc: remove the incorrect and misleading comment
zram: remove zcomp_stream_put() from write_incompressible_page()
mm: separate move/undo parts from migrate_pages_batch()
mm/kfence: use str_write_read() helper in get_access_type()
selftests/mm/mkdirty: fix memory leak in test_uffdio_copy()
kasan: hw_tags: Use str_on_off() helper in kasan_init_hw_tags()
selftests/mm: virtual_address_range: avoid reading from VM_IO mappings
selftests/mm: vm_util: split up /proc/self/smaps parsing
selftests/mm: virtual_address_range: unmap chunks after validation
selftests/mm: virtual_address_range: mmap() without PROT_WRITE
selftests/memfd/memfd_test: fix possible NULL pointer dereference
mm: add FGP_DONTCACHE folio creation flag
mm: call filemap_fdatawrite_range_kick() after IOCB_DONTCACHE issue
...
Remove highest_bit and lowest_bit. After the HDD allocation path has been
removed, the only purpose of these two fields is to determine whether the
device is full or not, which can instead be determined by checking the
inuse_pages.
Link: https://lkml.kernel.org/r/20250113175732.48099-6-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chis Li <chrisl@kernel.org>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickens <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The function btrfs_cleanup_ordered_extents() is only called in error
handling path, and the last caller with a @locked_folio parameter was
removed to fix a bug in the btrfs_run_delalloc_range() error handling.
There is no need to pass @locked_folio parameter anymore.
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
All the error handling bugs I hit so far are all -ENOSPC from either:
- cow_file_range()
- run_delalloc_nocow()
- submit_uncompressed_range()
Previously when those functions failed, there was no error message at
all, making the debugging much harder.
So here we introduce extra error messages for:
- cow_file_range()
- run_delalloc_nocow()
- submit_uncompressed_range()
- writepage_delalloc() when btrfs_run_delalloc_range() failed
- extent_writepage() when extent_writepage_io() failed
One example of the new debug error messages is the following one:
run fstests generic/750 at 2024-12-08 12:41:41
BTRFS: device fsid 461b25f5-e240-4543-8deb-e7c2bd01a6d3 devid 1 transid 8 /dev/mapper/test-scratch1 (253:4) scanned by mount (2436600)
BTRFS info (device dm-4): first mount of filesystem 461b25f5-e240-4543-8deb-e7c2bd01a6d3
BTRFS info (device dm-4): using crc32c (crc32c-arm64) checksum algorithm
BTRFS info (device dm-4): forcing free space tree for sector size 4096 with page size 65536
BTRFS info (device dm-4): using free-space-tree
BTRFS warning (device dm-4): read-write for sector size 4096 with page size 65536 is experimental
BTRFS info (device dm-4): checking UUID tree
BTRFS error (device dm-4): cow_file_range failed, root=363 inode=412 start=503808 len=98304: -28
BTRFS error (device dm-4): run_delalloc_nocow failed, root=363 inode=412 start=503808 len=98304: -28
BTRFS error (device dm-4): failed to run delalloc range, root=363 ino=412 folio=458752 submit_bitmap=11-15 start=503808 len=98304: -28
Which shows an error from cow_file_range() which is called inside a
nocow write attempt, along with the extra bitmap from
writepage_delalloc().
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
With CONFIG_DEBUG_VM set, test case generic/476 has some chance to crash
with the following VM_BUG_ON_FOLIO():
BTRFS error (device dm-3): cow_file_range failed, start 1146880 end 1253375 len 106496 ret -28
BTRFS error (device dm-3): run_delalloc_nocow failed, start 1146880 end 1253375 len 106496 ret -28
page: refcount:4 mapcount:0 mapping:00000000592787cc index:0x12 pfn:0x10664
aops:btrfs_aops [btrfs] ino:101 dentry name(?):"f1774"
flags: 0x2fffff80004028(uptodate|lru|private|node=0|zone=2|lastcpupid=0xfffff)
page dumped because: VM_BUG_ON_FOLIO(!folio_test_locked(folio))
------------[ cut here ]------------
kernel BUG at mm/page-writeback.c:2992!
Internal error: Oops - BUG: 00000000f2000800 [#1] SMP
CPU: 2 UID: 0 PID: 3943513 Comm: kworker/u24:15 Tainted: G OE 6.12.0-rc7-custom+ #87
Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Hardware name: QEMU KVM Virtual Machine, BIOS unknown 2/2/2022
Workqueue: events_unbound btrfs_async_reclaim_data_space [btrfs]
pc : folio_clear_dirty_for_io+0x128/0x258
lr : folio_clear_dirty_for_io+0x128/0x258
Call trace:
folio_clear_dirty_for_io+0x128/0x258
btrfs_folio_clamp_clear_dirty+0x80/0xd0 [btrfs]
__process_folios_contig+0x154/0x268 [btrfs]
extent_clear_unlock_delalloc+0x5c/0x80 [btrfs]
run_delalloc_nocow+0x5f8/0x760 [btrfs]
btrfs_run_delalloc_range+0xa8/0x220 [btrfs]
writepage_delalloc+0x230/0x4c8 [btrfs]
extent_writepage+0xb8/0x358 [btrfs]
extent_write_cache_pages+0x21c/0x4e8 [btrfs]
btrfs_writepages+0x94/0x150 [btrfs]
do_writepages+0x74/0x190
filemap_fdatawrite_wbc+0x88/0xc8
start_delalloc_inodes+0x178/0x3a8 [btrfs]
btrfs_start_delalloc_roots+0x174/0x280 [btrfs]
shrink_delalloc+0x114/0x280 [btrfs]
flush_space+0x250/0x2f8 [btrfs]
btrfs_async_reclaim_data_space+0x180/0x228 [btrfs]
process_one_work+0x164/0x408
worker_thread+0x25c/0x388
kthread+0x100/0x118
ret_from_fork+0x10/0x20
Code: 910a8021 a90363f7 a9046bf9 94012379 (d4210000)
---[ end trace 0000000000000000 ]---
[CAUSE]
The first two lines of extra debug messages show the problem is caused
by the error handling of run_delalloc_nocow().
E.g. we have the following dirtied range (4K blocksize 4K page size):
0 16K 32K
|//////////////////////////////////////|
| Pre-allocated |
And the range [0, 16K) has a preallocated extent.
- Enter run_delalloc_nocow() for range [0, 16K)
Which found range [0, 16K) is preallocated, can do the proper NOCOW
write.
- Enter fallback_to_fow() for range [16K, 32K)
Since the range [16K, 32K) is not backed by preallocated extent, we
have to go COW.
- cow_file_range() failed for range [16K, 32K)
So cow_file_range() will do the clean up by clearing folio dirty,
unlock the folios.
Now the folios in range [16K, 32K) is unlocked.
- Enter extent_clear_unlock_delalloc() from run_delalloc_nocow()
Which is called with PAGE_START_WRITEBACK to start page writeback.
But folios can only be marked writeback when it's properly locked,
thus this triggered the VM_BUG_ON_FOLIO().
Furthermore there is another hidden but common bug that
run_delalloc_nocow() is not clearing the folio dirty flags in its error
handling path.
This is the common bug shared between run_delalloc_nocow() and
cow_file_range().
[FIX]
- Clear folio dirty for range [@start, @cur_offset)
Introduce a helper, cleanup_dirty_folios(), which
will find and lock the folio in the range, clear the dirty flag and
start/end the writeback, with the extra handling for the
@locked_folio.
- Introduce a helper to clear folio dirty, start and end writeback
- Introduce a helper to record the last failed COW range end
This is to trace which range we should skip, to avoid double
unlocking.
- Skip the failed COW range for the error handling
CC: stable@vger.kernel.org
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
When testing with COW fixup marked as BUG_ON() (this is involved with the
new pin_user_pages*() change, which should not result new out-of-band
dirty pages), I hit a crash triggered by the BUG_ON() from hitting COW
fixup path.
This BUG_ON() happens just after a failed btrfs_run_delalloc_range():
BTRFS error (device dm-2): failed to run delalloc range, root 348 ino 405 folio 65536 submit_bitmap 6-15 start 90112 len 106496: -28
------------[ cut here ]------------
kernel BUG at fs/btrfs/extent_io.c:1444!
Internal error: Oops - BUG: 00000000f2000800 [#1] SMP
CPU: 0 UID: 0 PID: 434621 Comm: kworker/u24:8 Tainted: G OE 6.12.0-rc7-custom+ #86
Hardware name: QEMU KVM Virtual Machine, BIOS unknown 2/2/2022
Workqueue: events_unbound btrfs_async_reclaim_data_space [btrfs]
pc : extent_writepage_io+0x2d4/0x308 [btrfs]
lr : extent_writepage_io+0x2d4/0x308 [btrfs]
Call trace:
extent_writepage_io+0x2d4/0x308 [btrfs]
extent_writepage+0x218/0x330 [btrfs]
extent_write_cache_pages+0x1d4/0x4b0 [btrfs]
btrfs_writepages+0x94/0x150 [btrfs]
do_writepages+0x74/0x190
filemap_fdatawrite_wbc+0x88/0xc8
start_delalloc_inodes+0x180/0x3b0 [btrfs]
btrfs_start_delalloc_roots+0x174/0x280 [btrfs]
shrink_delalloc+0x114/0x280 [btrfs]
flush_space+0x250/0x2f8 [btrfs]
btrfs_async_reclaim_data_space+0x180/0x228 [btrfs]
process_one_work+0x164/0x408
worker_thread+0x25c/0x388
kthread+0x100/0x118
ret_from_fork+0x10/0x20
Code: aa1403e1 9402f3ef aa1403e0 9402f36f (d4210000)
---[ end trace 0000000000000000 ]---
[CAUSE]
That failure is mostly from cow_file_range(), where we can hit -ENOSPC.
Although the -ENOSPC is already a bug related to our space reservation
code, let's just focus on the error handling.
For example, we have the following dirty range [0, 64K) of an inode,
with 4K sector size and 4K page size:
0 16K 32K 48K 64K
|///////////////////////////////////////|
|#######################################|
Where |///| means page are still dirty, and |###| means the extent io
tree has EXTENT_DELALLOC flag.
- Enter extent_writepage() for page 0
- Enter btrfs_run_delalloc_range() for range [0, 64K)
- Enter cow_file_range() for range [0, 64K)
- Function btrfs_reserve_extent() only reserved one 16K extent
So we created extent map and ordered extent for range [0, 16K)
0 16K 32K 48K 64K
|////////|//////////////////////////////|
|<- OE ->|##############################|
And range [0, 16K) has its delalloc flag cleared.
But since we haven't yet submit any bio, involved 4 pages are still
dirty.
- Function btrfs_reserve_extent() returns with -ENOSPC
Now we have to run error cleanup, which will clear all
EXTENT_DELALLOC* flags and clear the dirty flags for the remaining
ranges:
0 16K 32K 48K 64K
|////////| |
| | |
Note that range [0, 16K) still has its pages dirty.
- Some time later, writeback is triggered again for the range [0, 16K)
since the page range still has dirty flags.
- btrfs_run_delalloc_range() will do nothing because there is no
EXTENT_DELALLOC flag.
- extent_writepage_io() finds page 0 has no ordered flag
Which falls into the COW fixup path, triggering the BUG_ON().
Unfortunately this error handling bug dates back to the introduction of
btrfs. Thankfully with the abuse of COW fixup, at least it won't crash
the kernel.
[FIX]
Instead of immediately unlocking the extent and folios, we keep the extent
and folios locked until either erroring out or the whole delalloc range
finished.
When the whole delalloc range finished without error, we just unlock the
whole range with PAGE_SET_ORDERED (and PAGE_UNLOCK for !keep_locked
cases), with EXTENT_DELALLOC and EXTENT_LOCKED cleared.
And the involved folios will be properly submitted, with their dirty
flags cleared during submission.
For the error path, it will be a little more complex:
- The range with ordered extent allocated (range (1))
We only clear the EXTENT_DELALLOC and EXTENT_LOCKED, as the remaining
flags are cleaned up by
btrfs_mark_ordered_io_finished()->btrfs_finish_one_ordered().
For folios we finish the IO (clear dirty, start writeback and
immediately finish the writeback) and unlock the folios.
- The range with reserved extent but no ordered extent (range(2))
- The range we never touched (range(3))
For both range (2) and range(3) the behavior is not changed.
Now even if cow_file_range() failed halfway with some successfully
reserved extents/ordered extents, we will keep all folios clean, so
there will be no future writeback triggered on them.
CC: stable@vger.kernel.org
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
If we failed to compress the range, or cannot reserve a large enough
data extent (e.g. too fragmented free space), we will fall back to
submit_uncompressed_range().
But inside submit_uncompressed_range(), run_delalloc_cow() can also fail
due to -ENOSPC or any other error.
In that case there are 3 bugs in the error handling:
1) Double freeing for the same ordered extent
This can lead to crash due to ordered extent double accounting
2) Start/end writeback without updating the subpage writeback bitmap
3) Unlock the folio without clear the subpage lock bitmap
Both bugs 2) and 3) will crash the kernel if the btrfs block size is
smaller than folio size, as the next time the folio gets writeback/lock
updates, subpage will find the bitmap already have the range set,
triggering an ASSERT().
[CAUSE]
Bug 1) happens in the following call chain:
submit_uncompressed_range()
|- run_delalloc_cow()
| |- cow_file_range()
| |- btrfs_reserve_extent()
| Failed with -ENOSPC or whatever error
|
|- btrfs_clean_up_ordered_extents()
| |- btrfs_mark_ordered_io_finished()
| Which cleans all the ordered extents in the async_extent range.
|
|- btrfs_mark_ordered_io_finished()
Which cleans the folio range.
The finished ordered extents may not be immediately removed from the
ordered io tree, as they are removed inside a work queue.
So the second btrfs_mark_ordered_io_finished() may find the finished but
not-yet-removed ordered extents, and double free them.
Furthermore, the second btrfs_mark_ordered_io_finished() is not subpage
compatible, as it uses fixed folio_pos() with PAGE_SIZE, which can cover
other ordered extents.
Bugs 2) and 3) are more straightforward, btrfs just calls folio_unlock(),
folio_start_writeback() and folio_end_writeback(), other than the helpers
which handle subpage cases.
[FIX]
For bug 1) since the first btrfs_cleanup_ordered_extents() call is
handling the whole range, we should not do the second
btrfs_mark_ordered_io_finished() call.
And for the first btrfs_cleanup_ordered_extents(), we no longer need to
pass the @locked_page parameter, as we are already in the async extent
context, thus will never rely on the error handling inside
btrfs_run_delalloc_range().
So just let the btrfs_clean_up_ordered_extents() handle every folio
equally.
For bug 2) we should not even call
folio_start_writeback()/folio_end_writeback() anymore.
As the error handling protocol, cow_file_range() should clear
dirty flag and start/finish the writeback for the whole range passed in.
For bug 3) just change the folio_unlock() to btrfs_folio_end_lock()
helper.
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
When running btrfs with block size (4K) smaller than page size (64K,
aarch64), there is a very high chance to crash the kernel at
generic/750, with the following messages:
(before the call traces, there are 3 extra debug messages added)
BTRFS warning (device dm-3): read-write for sector size 4096 with page size 65536 is experimental
BTRFS info (device dm-3): checking UUID tree
hrtimer: interrupt took 5451385 ns
BTRFS error (device dm-3): cow_file_range failed, root=4957 inode=257 start=1605632 len=69632: -28
BTRFS error (device dm-3): run_delalloc_nocow failed, root=4957 inode=257 start=1605632 len=69632: -28
BTRFS error (device dm-3): failed to run delalloc range, root=4957 ino=257 folio=1572864 submit_bitmap=8-15 start=1605632 len=69632: -28
------------[ cut here ]------------
WARNING: CPU: 2 PID: 3020984 at ordered-data.c:360 can_finish_ordered_extent+0x370/0x3b8 [btrfs]
CPU: 2 UID: 0 PID: 3020984 Comm: kworker/u24:1 Tainted: G OE 6.13.0-rc1-custom+ #89
Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Hardware name: QEMU KVM Virtual Machine, BIOS unknown 2/2/2022
Workqueue: events_unbound btrfs_async_reclaim_data_space [btrfs]
pc : can_finish_ordered_extent+0x370/0x3b8 [btrfs]
lr : can_finish_ordered_extent+0x1ec/0x3b8 [btrfs]
Call trace:
can_finish_ordered_extent+0x370/0x3b8 [btrfs] (P)
can_finish_ordered_extent+0x1ec/0x3b8 [btrfs] (L)
btrfs_mark_ordered_io_finished+0x130/0x2b8 [btrfs]
extent_writepage+0x10c/0x3b8 [btrfs]
extent_write_cache_pages+0x21c/0x4e8 [btrfs]
btrfs_writepages+0x94/0x160 [btrfs]
do_writepages+0x74/0x190
filemap_fdatawrite_wbc+0x74/0xa0
start_delalloc_inodes+0x17c/0x3b0 [btrfs]
btrfs_start_delalloc_roots+0x17c/0x288 [btrfs]
shrink_delalloc+0x11c/0x280 [btrfs]
flush_space+0x288/0x328 [btrfs]
btrfs_async_reclaim_data_space+0x180/0x228 [btrfs]
process_one_work+0x228/0x680
worker_thread+0x1bc/0x360
kthread+0x100/0x118
ret_from_fork+0x10/0x20
---[ end trace 0000000000000000 ]---
BTRFS critical (device dm-3): bad ordered extent accounting, root=4957 ino=257 OE offset=1605632 OE len=16384 to_dec=16384 left=0
BTRFS critical (device dm-3): bad ordered extent accounting, root=4957 ino=257 OE offset=1622016 OE len=12288 to_dec=12288 left=0
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008
BTRFS critical (device dm-3): bad ordered extent accounting, root=4957 ino=257 OE offset=1634304 OE len=8192 to_dec=4096 left=0
CPU: 1 UID: 0 PID: 3286940 Comm: kworker/u24:3 Tainted: G W OE 6.13.0-rc1-custom+ #89
Hardware name: QEMU KVM Virtual Machine, BIOS unknown 2/2/2022
Workqueue: btrfs_work_helper [btrfs] (btrfs-endio-write)
pstate: 404000c5 (nZcv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : process_one_work+0x110/0x680
lr : worker_thread+0x1bc/0x360
Call trace:
process_one_work+0x110/0x680 (P)
worker_thread+0x1bc/0x360 (L)
worker_thread+0x1bc/0x360
kthread+0x100/0x118
ret_from_fork+0x10/0x20
Code: f84086a1 f9000fe1 53041c21 b9003361 (f9400661)
---[ end trace 0000000000000000 ]---
Kernel panic - not syncing: Oops: Fatal exception
SMP: stopping secondary CPUs
SMP: failed to stop secondary CPUs 2-3
Dumping ftrace buffer:
(ftrace buffer empty)
Kernel Offset: 0x275bb9540000 from 0xffff800080000000
PHYS_OFFSET: 0xffff8fbba0000000
CPU features: 0x100,00000070,00801250,8201720b
[CAUSE]
The above warning is triggered immediately after the delalloc range
failure, this happens in the following sequence:
- Range [1568K, 1636K) is dirty
1536K 1568K 1600K 1636K 1664K
| |/////////|////////| |
Where 1536K, 1600K and 1664K are page boundaries (64K page size)
- Enter extent_writepage() for page 1536K
- Enter run_delalloc_nocow() with locked page 1536K and range
[1568K, 1636K)
This is due to the inode having preallocated extents.
- Enter cow_file_range() with locked page 1536K and range
[1568K, 1636K)
- btrfs_reserve_extent() only reserved two extents
The main loop of cow_file_range() only reserved two data extents,
Now we have:
1536K 1568K 1600K 1636K 1664K
| |<-->|<--->|/|///////| |
1584K 1596K
Range [1568K, 1596K) has an ordered extent reserved.
- btrfs_reserve_extent() failed inside cow_file_range() for file offset
1596K
This is already a bug in our space reservation code, but for now let's
focus on the error handling path.
Now cow_file_range() returned -ENOSPC.
- btrfs_run_delalloc_range() do error cleanup <<< ROOT CAUSE
Call btrfs_cleanup_ordered_extents() with locked folio 1536K and range
[1568K, 1636K)
Function btrfs_cleanup_ordered_extents() normally needs to skip the
ranges inside the folio, as it will normally be cleaned up by
extent_writepage().
Such split error handling is already problematic in the first place.
What's worse is the folio range skipping itself, which is not taking
subpage cases into consideration at all, it will only skip the range
if the page start >= the range start.
In our case, the page start < the range start, since for subpage cases
we can have delalloc ranges inside the folio but not covering the
folio.
So it doesn't skip the page range at all.
This means all the ordered extents, both [1568K, 1584K) and
[1584K, 1596K) will be marked as IOERR.
And these two ordered extents have no more pending ios, they are marked
finished, and *QUEUED* to be deleted from the io tree.
- extent_writepage() do error cleanup
Call btrfs_mark_ordered_io_finished() for the range [1536K, 1600K).
Although ranges [1568K, 1584K) and [1584K, 1596K) are finished, the
deletion from io tree is async, it may or may not happen at this
time.
If the ranges have not yet been removed, we will do double cleaning on
those ranges, triggering the above ordered extent warnings.
In theory there are other bugs, like the cleanup in extent_writepage()
can cause double accounting on ranges that are submitted asynchronously
(compression for example).
But that's much harder to trigger because normally we do not mix regular
and compression delalloc ranges.
[FIX]
The folio range split is already buggy and not subpage compatible, it
was introduced a long time ago where subpage support was not even considered.
So instead of splitting the ordered extents cleanup into the folio range
and out of folio range, do all the cleanup inside writepage_delalloc().
- Pass @NULL as locked_folio for btrfs_cleanup_ordered_extents() in
btrfs_run_delalloc_range()
- Skip the btrfs_cleanup_ordered_extents() if writepage_delalloc()
failed
So all ordered extents are only cleaned up by
btrfs_run_delalloc_range().
- Handle the ranges that already have ordered extents allocated
If part of the folio already has ordered extent allocated, and
btrfs_run_delalloc_range() failed, we also need to cleanup that range.
Now we have a concentrated error handling for ordered extents during
btrfs_run_delalloc_range().
Fixes: d1051d6ebf ("btrfs: Fix error handling in btrfs_cleanup_ordered_extents")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have several places explicitly calling btrfs_mark_buffer_dirty() but
that is not necessarily since the target leaf came from a path that was
obtained for a btree search function that modifies the btree, something
like btrfs_insert_empty_item() or anything else that ends up calling
btrfs_search_slot() with a value of 1 for its 'cow' argument.
These just make the code more verbose, confusing and add a little extra
overhead and well as increase the module's text size, so remove them.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
During renames we are grouping transaction aborts that can be due to a
failure of one of several function calls. While this makes the code less
verbose, it makes it harder to debug as we end up not knowing from which
function call we got an error.
So change this to trigger a transaction abort after each function call
failure, so that when we get a transaction abort message we know exactly
which function call failed, helping us to debug issues.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Instead of passing a root and an objectid which matches an inode number,
pass the inode instead, since the root is always the root associated to
the inode and the objectid is the number of that inode.
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>
All callers of can_nocow_extent() now pass a value of false for its
'strict' argument, making it redundant. So remove the argument from
can_nocow_extent() as well as can_nocow_file_extent(),
btrfs_cross_ref_exist() and check_committed_ref(), because this
argument was used just to influence the behavior of check_committed_ref().
Also remove the 'strict' field from struct can_nocow_file_extent_args,
which is now always false as well, as its value is taken from the
argument to can_nocow_extent().
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since commit e1e577aafe41 ("btrfs: store fs_info in space_info"), we have
the fs_info in a space_info. So, we can drop fs_info argument from
btrfs_update_space_info_*. There is no behavior change.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
