ext4_get_link() follows a symlink that keeps its target in a data block
in rcu pathwalk mode with ext4_getblk(EXT4_GET_BLOCKS_CACHED_NOWAIT).
That reads s_mount_state in the ASSERT() of ext4_getblk() and again in
ext4_es_lookup_extent(), and the lookup bumps the extent status hit or
miss counter, all through sb->s_fs_info.
ext4_put_super() destroys those counters, clears sb->s_fs_info and frees
the sbi without waiting for a grace period. A pathwalk that is still in
ext4_get_link() when the last reference to the mount goes away then
dereferences a NULL s_fs_info, the freed sbi or the destroyed percpu
counters.
With a pathwalk held up in ext4_get_link() while the last reference
goes away:
KASAN: null-ptr-deref in range [0x00000000000000a8-0x00000000000000af]
RIP: 0010:ext4_getblk+0xf0/0x640
Call Trace:
<TASK>
ext4_get_link+0x26c/0x410
pick_link+0xf96/0x1780
step_into_slowpath+0x9b8/0x1250
path_lookupat+0x484/0xb00
filename_lookup+0x1f1/0x5b0
vfs_statx+0xd7/0x3b0
vfs_fstatat+0x4d/0x90
__do_sys_newfstatat+0xa0/0x100
do_syscall_64+0x10e/0x5e0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
So far that has been hard to hit. umount(2) waits for a grace period in
namespace_unlock() before it drops the mount, so only a mount whose last
reference goes away elsewhere, like the close of a file or a chdir out of
a lazily unmounted directory, can race a walker.
Keep sb->s_fs_info and free the sbi together with the extent status
counters after a grace period. Split the counters out of
ext4_es_unregister_shrinker() for that. The shrinker still gets wasted
in ext4_put_super(), the counters go with the sbi.
Fixes: 6493792d32 ("ext4: convert symlink external data block mapping to bdev")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20261009-work-fixes-rcu-v1-1-7446d2d335e6@kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
* Improve performance by allowing parallel DIO writes when we were
previously being overly conservative when checking whether it was safe
to avoid requiring an exclusive lock
* Improve the performance of ext4_mb_prefetch() used by fallocate() by
avoiding work when it is not needed
* Remove the unnecessary custom end_io function ext4_end_buffer_io_sync()
* Improve performance when performing an overwrite to an already uptodate folio
* Clean up how we handle deallocating EA inodes to avoid a potential
lock ordering issue when there is a failed mount while an EA inode is
still being evicted.
* Use str_plural() instead of a custom macro
* Avoid soft lockups or RCU stalls if there are many busy buffers
(caused by heavy I/O) while checkpointing
* Use scoped NOFS when starting a handle in nojournal mode
* Align fields in handle structure to optimize setting and getting
the h_type and h_line_no fields
* Fix documentation of the meta_bg block group layout
* Bug fixes, including
- Fix a potential out-of-bounds read in ext4_read_inline_dir()
- Fix a potential deadlock when concurrent xattr operations are racing
with each other when some of the xattrs are using the ea_inode feature.
- Fix a spurious warning with data=journal that can be triggered when
writeback races with remounting the file system read-only
- Fix a potential deadlock when EXT4_IOC_MIGRATE races with a file system
freeze operation
- Make sure all in-flight direct I/O operations are complete before
falling back to buffered I/O.
- Handle IOCB_NOWAIT properly when performing a extending DAX write
- Prevent potentially sleeping on a block allocation when
IOCB_NOWAIT is set
- Fix potential races when racing an inline data write with a page fault
- Propagate errors when adding or removing extent ranges
during a fast commit replay
- Avoid trying to expand an inode's extra size when it is being
evicted to avoid a number of corner case or deadlocks
- Avoid spurious error when retrying inode extra size expansion
- Fix corner cases where we underestimate the number of journal
credits needed
- Avoid hangs/crashes/WARNINGS caused by maliciously corrupted
file systems
- Don't issue spurious orphan clean message on RO file systems
- Avoid leaving the file system in an inconsistent state after a
crash when a WRITE_ZEROS in progress converting an unwritten
extent to a written extent
- Handle WRITE_ZEROS correctly when there are some partially dirtied
regions in the page cache
- Pass errors during zero-rage, truncate, or punch hole to the caller
if ext4_get_block() fails
- Wait for writeback to finish when triggered by zero-range or
zero-range for those devices that require stable writes
- If the reserved gid superblock field is set, set the reserved gid
instead of the reserved uid
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Merge tag 'ext4_for_linus-7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
- Improve performance by allowing parallel DIO writes when we were
previously being overly conservative when checking whether it was
safe to avoid requiring an exclusive lock
- Improve the performance of ext4_mb_prefetch() used by fallocate() by
avoiding work when it is not needed
- Remove the unnecessary custom end_io function
ext4_end_buffer_io_sync()
- Improve performance when performing an overwrite to an already
uptodate folio
- Clean up how we handle deallocating EA inodes to avoid a potential
lock ordering issue when there is a failed mount while an EA inode is
still being evicted
- Use str_plural() instead of a custom macro
- Avoid soft lockups or RCU stalls if there are many busy buffers
(caused by heavy I/O) while checkpointing
- Use scoped NOFS when starting a handle in nojournal mode
- Align fields in handle structure to optimize setting and getting the
h_type and h_line_no fields
- Fix documentation of the meta_bg block group layout
- Bug fixes:
- Fix a potential out-of-bounds read in ext4_read_inline_dir()
- Fix a potential deadlock when concurrent xattr operations are
racing with each other when some of the xattrs are using the
ea_inode feature
- Fix a spurious warning with data=journal that can be triggered
when writeback races with remounting the file system read-only
- Fix a potential deadlock when EXT4_IOC_MIGRATE races with a file
system freeze operation
- Make sure all in-flight direct I/O operations are complete before
falling back to buffered I/O
- Handle IOCB_NOWAIT properly when performing a extending DAX write
- Prevent potentially sleeping on a block allocation when
IOCB_NOWAIT is set
- Fix potential races when racing an inline data write with a page
fault
- Propagate errors when adding or removing extent ranges during a
fast commit replay
- Avoid trying to expand an inode's extra size when it is being
evicted to avoid a number of corner case or deadlocks
- Avoid spurious error when retrying inode extra size expansion
- Fix corner cases where we underestimate the number of journal
credits needed
- Avoid hangs/crashes/WARNINGS caused by maliciously corrupted file
systems
- Don't issue spurious orphan clean message on RO file systems
- Avoid leaving the file system in an inconsistent state after a
crash when a WRITE_ZEROS in progress converting an unwritten
extent to a written extent
- Handle WRITE_ZEROS correctly when there are some partially dirtied
regions in the page cache
- Pass errors during zero-rage, truncate, or punch hole to the
caller if ext4_get_block() fails
- Wait for writeback to finish when triggered by zero-range or
zero-range for those devices that require stable writes
- If the reserved gid superblock field is set, set the reserved gid
instead of the reserved uid
* tag 'ext4_for_linus-7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (56 commits)
ext4: fix estimate extent index blocks in ext4_ext_index_trans_blocks()
ext4: fix transaction overflow during writeback
ext4: teach ext4_meta_trans_blocks() about number of allocated extents
ext4: guard against NULL s_group_info in ext4_get_group_info
ext4: fix spurious message about orphan cleanup on RO fs
ext4: stop retrying saturated xattr cache entries
ext4: don't enable DAX on new encrypted files
ext4: protect WRITE_ZEROES written extents with orphan list
ext4: export converted block count from ext4_convert_unwritten_extents()
ext4: fix incorrect function call when initializing s_resgid
ext4: validate EA inode i_nlink in ext4_xattr_inode_iget
jbd2: align h_type and h_line_no in the handle structure on byte boundaries
ext4: enable scoped NOFS when starting a handle in nojournal mode
ext4: write back partial-zeroed edges in WRITE_ZEROES
ext4: zero out whole block for clean edges in WRITE_ZEROES
ext4: track partial-zero outcome per edge in ext4_zero_partial_blocks()
ext4: clarify return semantics of ext4_load_tail_bh()
ext4: move partial block zeroing earlier in ext4_zero_range()
ext4: check return value of ext4_get_block() in ext4_load_tail_bh()
ext4: skip tail block zeroing for inline data files
...
The main change this cycle is a significant simplification that's been
overdue for a while now: standardizing on a single file contents
encryption implementation in ext4 and f2fs, instead of having two.
Specifically, the original filesystem-layer file contents encryption
implementation is removed, and the blk-crypto implementation is now
used unconditionally. blk-crypto delegates either to inline crypto
hardware or to the CPU via blk-crypto-fallback. The latter is
functionally equivalent to the original filesystem-layer code.
The blk-crypto implementation already existed, but previously it was
used only when the filesystem was mounted with "-o inlinecrypt". Now,
"-o inlinecrypt" just selects whether inline crypto hardware is used.
To allow maintaining that user control over hardware use, the
blk-crypto API is extended with a new flag BLK_CRYPTO_CFG_ALLOW_HW.
Overall, this removes quite a bit of redundant code from ext4, f2fs,
and fs/crypto/. It should make things easier for ongoing filesystem
efforts such as iomap support, large folios, and btrfs encryption.
(btrfs had already been planning to use blk-crypto exclusively.)
There are two small behavior changes of note:
- Direct I/O now works on encrypted files even without
"-o inlinecrypt", rather than falling back to buffered I/O. This is
effectively a bugfix, though I'll continue to keep an eye out for
any user that may have been depending on the buffered I/O fallback.
- IV_INO_LBLK_32 policies are no longer supported in certain cases
that didn't make sense and have no known uses.
This has been in linux-next since July 22 with no reported issues.
All encryption xfstests pass on ext4 and f2fs. As usual I've also been
using it on a system with an fscrypt-encrypted home directory. Of
course, the blk-crypto code paths also aren't new and were already
being used on many systems via the inlinecrypt mount option.
In addition to the main change described above, there are a few other
cleanups such as using lock guards for mutexes, improving
documentation, and removing a workaround for outdated gcc versions.
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Merge tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/linux
Pull fscrypt updates from Eric Biggers:
"The main change this cycle is a significant simplification that's been
overdue for a while now: standardizing on a single file contents
encryption implementation in ext4 and f2fs, instead of having two.
Specifically, the original filesystem-layer file contents encryption
implementation is removed, and the blk-crypto implementation is now
used unconditionally. blk-crypto delegates either to inline crypto
hardware or to the CPU via blk-crypto-fallback. The latter is
functionally equivalent to the original filesystem-layer code.
The blk-crypto implementation already existed, but previously it was
used only when the filesystem was mounted with "-o inlinecrypt". Now,
"-o inlinecrypt" just selects whether inline crypto hardware is used.
To allow maintaining that user control over hardware use, the
blk-crypto API is extended with a new flag BLK_CRYPTO_CFG_ALLOW_HW.
Overall, this removes quite a bit of redundant code from ext4, f2fs,
and fs/crypto/. It should make things easier for ongoing filesystem
efforts such as iomap support, large folios, and btrfs encryption
(btrfs had already been planning to use blk-crypto exclusively.)
There are two small behavior changes of note:
- Direct I/O now works on encrypted files even without "-o inlinecrypt",
rather than falling back to buffered I/O. This is effectively a
bugfix, though I'll continue to keep an eye out for any user that
may have been depending on the buffered I/O fallback.
- IV_INO_LBLK_32 policies are no longer supported in certain cases
that didn't make sense and have no known uses.
This has been in linux-next since July 22 with no reported issues. All
encryption xfstests pass on ext4 and f2fs. As usual I've also been
using it on a system with an fscrypt-encrypted home directory. Of
course, the blk-crypto code paths also aren't new and were already
being used on many systems via the inlinecrypt mount option.
In addition to the main change described above, there are a few other
cleanups such as using lock guards for mutexes, improving
documentation, and removing a workaround for outdated gcc versions"
* tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/linux: (29 commits)
blk-crypto: Update docs for blk-crypto-fallback motivation
blk-crypto: Remove unused function blk_crypto_config_supported()
fscrypt: Update docs for data path
fscrypt: Remove unused function fscrypt_finalize_bounce_page()
f2fs: Update outdated comment in f2fs_write_begin()
fs: Update outdated comment for SB_INLINECRYPT
fscrypt: Update encryption policy version docs
fscrypt: Replace some variable-size memsets with fixed-size
fscrypt: Add safety checks to non-block-based en/decryption
fscrypt: Merge bio.c and inline_crypt.c into block.c
fscrypt: Remove unused functions and workqueue
fscrypt: Remove fs-layer zeroout code
fscrypt: Remove fscrypt_dio_supported()
fscrypt: Replace calls to fscrypt_inode_uses_inline_crypto()
fs/buffer: Remove fs-layer decryption code
f2fs: Remove fs-layer file contents en/decryption code
ext4: Further de-generalize the bio postprocessing code
ext4: Make ext4_bio_write_folio() return void
ext4: Remove fs-layer file contents en/decryption code
Documentation: fscrypt: Update docs for inlinecrypt
...
Please consider pulling these changes from the signed vfs-7.3-rc1.sync tag.
Thanks!
Christian
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Merge tag 'vfs-7.3-rc1.sync' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs writeback updates from Christian Brauner:
"This makes sync_inode_metadata() and writeback_single_inode() persist
not only the inode but all metadata associated with it.
A new .sync_inode_metadata superblock operation is called from
__writeback_single_inode(). Alongside it a new I_METADATA_WRITEBACK
state flag is added.
Filesystems no longer need their own mmb_fsync() implementations and
can just use simple_fsync(). All metadata is now written for IS_SYNC
and IS_DIRSYNC inodes. Races where several fsyncs raced and mmb_sync()
could return before all buffers were really persisted are fixed since
I_SYNC now serializes properly.
The I_METADATA_WRITEBACK scheme also fixes the case where a
WB_SYNC_NONE writeback landing between write(2) and fsync(2) left
fsync(2) failing to persist the inode. That problem is not specific to
filesystems using the generic metadata bh tracking, and the ones that
do not are left alone.
ext2, udf, bfs, minix, fat and ext4 in nojournal mode have their data
integrity writeout fixed and are converted. affs drops metadata bh
tracking and mmb_fsync() is removed.
A few other fixes came out of this:
- a UAF in mark_buffer_write_io_error()
- missed inode writeback when racing with __writeback_single_inode()
- ext4 allocating the mapping_metadata_bhs struct on demand
- three fat fixes: a lost inode update in do_msdos_rename() with
DIRSYNC, inode buffer write errors not propagating out of
fat_sync_inode_metadata() and directory entries not being
persisted on fsync(2) of the root directory"
* tag 'vfs-7.3-rc1.sync' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (24 commits)
writeback: Export __inode_attach_wb()
fat: Fix persisting directory entries on fsync(2) of the root directory
fat: Propagate inode buffer write errors from fat_sync_inode_metadata()
fat: Fix lost inode update in do_msdos_rename() with DIRSYNC
vfs: Remove mmb_fsync()
fat: Replace fat_sync_inode() with sync_inode_metadata()
fat: Fix missed inode writeback during fsync(2)
ext4: Fix data integrity writeout issues in nojournal mode
minix: Fix data integrity writeout issues
bfs: Fix data integrity writeout issues
udf: Fold udf_update_inode() into udf_write_inode()
udf: Use sync_inode_metadata() in udf_evict_inode()
udf: Drop udf_sync_inode()
udf: Use sync_inode_metadata() to writeout IS_SYNC inode
udf: Fix data integrity writeout issues
ext2: Fix data integrity writeout issues
ext2: Avoid unnecessary inode buffer writeback for sync(2)
ext2: Drop __ext2_write_inode()
ext2: Fix lost inode updates for IS_SYNC inodes
fs: Provide way for filesystem to wait for metadata writeback
...
So far ext4_meta_trans_blocks() expects that each extent counted in
@pextents will be allocated in the transaction we estimate credits for.
This is correct for the use in ext4_chunk_trans_blocks() and
ext4_chunk_trans_extent() however the use in atomic write path
(ext4_convert_unwritten_extents_atomic() and ext4_iomap_alloc() for
IOMAP_ATOMIC) unnecessarily overestimates the number of necessary
credits as neither of them allocates any data. Add argument to
ext4_meta_trans_blocks() for number of extents that are going to be
allocated in the transaction.
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260805153605.166545-4-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The pending iomap_iter_next conversion creates performance issues for the
new simple direct I/O read fast path, because it assumes a model where
the iterator must be advanced at the end, which the direct I/O read fast
path tries to avoid.
Side step this by splitting the simple path from iomap_dio_rw, and
require the file systems to call into it explicitly, and pass only a
->begin callback. This allows to drop various checks for incompatible
features while creating a requirement for the file system to only call
the simple path for cases that it can handle.
As a side-benefit we can now inline the initial part of the simple
direct I/O read fast path and let the compiler convert the indirect call
to ->begin into a direct call.
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Fengnan Chang <changfengnan@bytedance.com>
Reviewed-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260729192737.3190206-4-joannelkoong@gmail.com
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
ext4_convert_unwritten_extents() currently returns only a success or a
failure indication. A zero return means all requested blocks were
converted, and a negative value means the conversion failed. However,
some blocks may have already been converted when the function fails
partway through, and callers have no way to learn how many were done.
The WRITE_ZEROES caller in ext4_alloc_file_blocks() needs this
information to decide whether to add the inode to the orphan list before
updating i_disksize to cover the already-converted written extents, so
that a crash before i_disksize catches up can be recovered via orphan
truncation.
Switch the function to pass out the number of converted blocks through
the new output parameter @converted, which will be used by later
patches.
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260729085918.3336221-2-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Several racing fsyncs on ext4 in nojournal mode could result in some
fsync returning earlier than all metadata buffers were properly
persisted. Also ext4_fsync() in nojournal mode was somewhat inefficient
because it was always writing out the inode regardless whether it was
dirty or not.
Fix these issues by using new .sync_inode_metadata method which makes
sure all inode related metadata is written to disk during any
WB_SYNC_ALL writeback in nojournal mode. This also somewhat simplifies
the nojournal mode fsync handling.
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260727104923.3828017-37-jack@suse.cz
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Currently every ext4 inode gets mapping_metadata_bhs struct although it
is only needed when running without a journal and only for inodes where
any metadata was dirtied. Allocate mapping_metadata_bhs struct on demand
when dirtying the first metadata buffer for the inode.
Acked-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260727104923.3828017-24-jack@suse.cz
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Replace the single bool did_zero output of ext4_zero_partial_blocks()
with a bitmask that records which edge (start, end, or both in the
single-block case) was actually partial-zeroed. This allows callers to
distinguish which edges have been zeroed, preparing for unaligned
FALLOC_FL_WRITE_ZEROES handling in later patches.
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260714080044.4038124-7-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Calling iput() on EA inodes while holding xattr_sem or a jbd2 handle
can trigger write_inode_now() -> ext4_writepages() -> s_writepages_rwsem,
creating a lock ordering issue during mount (!SB_ACTIVE).
Add ext4_put_ea_inode() which uses iput_if_not_last() as a fast path.
If this is not the last reference, it is dropped immediately. If this
is the last reference, the inode is linked onto a per-sb lock-free llist
via i_ea_iput_node (embedded in ext4_inode_info, sharing space with the
unused xattr_sem of EA inodes via a union) and a delayed worker
(1 jiffie) performs the final iput() in a clean context. This avoids
per-iput memory allocation.
Flush points ensure all pending EA inode evictions complete before
dependent resources become unavailable:
- ext4_put_super / failed_mount9: before quota shutdown
- failed_mount_wq: before freeing xattr caches
- failed_mount3a: before freeing shrinker (journal replay case)
- ext4_sync_fs: before remount-ro, freeze, or sync completes
Initialization is placed before journal loading since fast commit
replay may trigger evictions that call ext4_put_ea_inode().
Also moves init_rwsem(xattr_sem) from init_once to ext4_alloc_inode to
handle slab object reuse after the union field has been overwritten.
Signed-off-by: Yun Zhou <yun.zhou@windriver.com>
Suggested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260710030851.2791589-3-yun.zhou@windriver.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
After implementing bitwise flags for tracking the inline data write
state in the address space fsdata parameter, the CONVERT_INLINE_DATA
state flag is left unused and can be removed.
Perform this clean-up by:
1) Deleting the CONVERT_INLINE_DATA definition from ext4.h.
2) Removing the void **fsdata argument from both the forward
declaration and the definition of the internal helper
ext4_da_convert_inline_data_to_extent().
3) Removing the void **fsdata argument from the declaration and
definition of ext4_generic_write_inline_data() and updating
the caller ext4_try_to_write_inline_data() and the internal
re-alloc retry logic accordingly.
4) Updating ext4_da_write_begin() to call
ext4_generic_write_inline_data() without the fsdata parameter.
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Aditya Prakash Srivastava <aditya.ansh182@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260703045414.1768-2-aditya.ansh182@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Instead of checking the live inode state (ext4_has_inline_data(inode)
and ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) in the
write_end handlers, use the fsdata parameter of the address space
operations to explicitly pass down the state in which write_begin
prepared the write.
A concurrent thread (such as ext4_page_mkwrite()) can convert the
inline data to an extent between write_begin and write_end. If this
happens, the write_end handlers would previously miss the inline
write_end path and fall through to extent-based write_end logic.
However, since block buffers were never allocated in write_begin,
this resulted in NULL pointer dereferences or data loss because
folio_buffers(folio) was NULL.
Define EXT4_WRITE_DATA_INLINE (4) as a bit flag (Bit 2), treating
fsdata as bitwise flags rather than mutually exclusive enums to keep
states of the write path independent. Communicate this state via
fsdata:
1) ext4_write_begin() and ext4_da_write_begin() set the
EXT4_WRITE_DATA_INLINE bit in *fsdata via bitwise OR when an inline
write is successfully prepared.
2) On entry, ext4_write_begin() clears the EXT4_WRITE_DATA_INLINE bit
to safely handle VFS retries (where generic_perform_write() bypasses
the fsdata initialization on its retry jump).
3) The write_end handlers perform a bitwise AND to check if the
EXT4_WRITE_DATA_INLINE bit is set and invoke the inline write_end
helper accordingly.
Furthermore, during a buffered write, ext4_write_inline_data_end()
acquires the xattr lock after preparing the write. If a concurrent
page fault (ext4_page_mkwrite()) converts the inline data to an extent
after the write_end handlers check the state but before
ext4_write_inline_data_end() acquires the xattr write lock, the
subsequent check will trigger a kernel panic via
BUG_ON(!ext4_has_inline_data(inode)).
To keep git history working and bisectability clean, replace the
BUG_ON check in ext4_write_inline_data_end() with a graceful error-
handling retry path in this same commit. If the inline data is cleared
after locking the xattr, we safely release all resources (releasing
iloc.bh, unlocking/putting the folio, stopping the active journal
transaction handle) and return 0 (VFS retry) to let the generic write
path retry the operation safely.
Reported-by: syzbot+0c89d865531d053abb2d@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=0c89d865531d053abb2d
Fixes: 3fdcfb668f ("ext4: add journalled write support for inline data")
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Aditya Prakash Srivastava <aditya.ansh182@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260703045414.1768-1-aditya.ansh182@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Syzbot/stress-ng reported an ABBA deadlock in ext4 when exercising
concurrent xattr workloads (using the ea_inode mount/format option).
The deadlock occurs between the running transaction and the eviction
thread:
- Task 1 (stress-ng): Holds a reference to a shared mbcache_entry (ce)
and calls ext4_xattr_inode_cache_find() -> ext4_iget() to retrieve
the corresponding EA inode. Since the EA inode is currently being
evicted, ext4_iget() blocks in __wait_on_freeing_inode() waiting for
eviction to complete.
- Task 2 (eviction thread): Currently evicting the same EA inode in
ext4_evict_ea_inode(). It calls mb_cache_entry_wait_unused(oe) which
blocks waiting for Task 1 to release the reference to the mbcache_entry.
To break this deadlock, implement a new ext4_iget() configuration flag
named EXT4_IGET_NOWAIT. When set, perform a non-blocking lookup of the
inode via VFS's find_inode_nowait() API.
If the inode is currently being evicted (marked with I_FREEING or
I_WILL_FREE) or created (I_CREATING), or if it is not present in the VFS
inode cache (cache miss), simply skip it (returning -ENOENT) rather than
waiting for eviction/creation to complete, breaking the ABBA cycle.
Since we return -ENOENT immediately on a cache miss, we never attempt to
allocate a new inode or call iget_locked(), completely eliminating any
TOCTOU race window.
If the returned inode is I_NEW, wait for its initialization to clear via
wait_on_new_inode(). If initialization fails and the inode is unhashed
during wait_on_new_inode() waking up (e.g., due to an I/O read error in
another thread), safely drop the reference and return -ENOENT. This
unhashed check is executed unconditionally on all cache-hit pathways to
properly handle concurrent initialization failures.
Finally, standard validation checks (including is_bad_inode,
EXT4_EA_INODE_FL, file_acl, and xattr flags) are executed as normal inside
check_igot_inode() to fully guarantee VFS-layer safety.
In ext4_xattr_inode_cache_find(), invoke ext4_iget() with the new
EXT4_IGET_NOWAIT flag to perform the non-blocking cache search.
Suggested-by: Jan Kara <jack@suse.cz>
Reported-by: Colin Ian King <colin.i.king@gmail.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219283
Fixes: 0a46ef2347 ("ext4: do not create EA inode under buffer lock")
Signed-off-by: Aditya Prakash Srivastava <aditya.ansh182@gmail.com>
Tested-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260626054821.1729-1-aditya.ansh182@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
EXT4_MB_GRP_TEST_AND_SET_READ uses test_and_set_bit function which
issues an atomic write. This can cause high overhead due to cache
contention when multiple threads iterate over groups in a tight loop,
as is the case for ext4_mb_prefetch(). We have seen this to be a
problem for Kunpeng 920b CPUs which uses a single ARM LSE instruction
for this purpose.
Avoid this unconditional atomic write by testing the bit first without
changing its value. This is OK for this use case as this bit is never
unset.
This change significantly reduces costs of fallocate() operations which
trigger linear group scans on large multicore machines where
test_and_set_bit issues an atomic write operation unconditionally.
Signed-off-by: Bohdan Trach <bohdan.trach@huaweicloud.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260615100331.163997-2-bohdan.trach@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The mke2fs man page documents:
Valid cluster-size values are from 2048 to 256M bytes per cluster.
but EXT4_MAX_CLUSTER_LOG_SIZE was set to 30 (1GB), allowing crafted
filesystem images to specify cluster sizes up to 1GB.
On 32-bit systems with bigalloc enabled, the consistency check in
ext4_handle_clustersize():
s_blocks_per_group == s_clusters_per_group * (clustersize / blocksize)
can overflow when the cluster ratio is large enough. Since
s_blocks_per_group is not range-checked in the bigalloc path, the
wrapped product can pass the consistency check, leading to inconsistent
group geometry and potential out-of-bounds block allocation.
Reduce EXT4_MAX_CLUSTER_LOG_SIZE to 28 to match the documented 256MB
limit. With this cap, the maximum product is:
(blocksize * 8) * (256M / blocksize) = 2^31
which fits safely in a 32-bit unsigned long for all block sizes.
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260608061112.392391-1-libaokun%40linux.alibaba.com
Signed-off-by: Baokun Li <libaokun@linux.alibaba.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Link: https://patch.msgid.link/20260608111150.827117-3-libaokun@linux.alibaba.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Since the bio postprocessing code in fs/ext4/readpage.c is now used only
for fsverity, rename things accordingly.
Also:
- Don't create the caches at all when !CONFIG_FS_VERITY.
- Remove the unused inode argument from ext4_set_verity_work().
Link: https://patch.msgid.link/20260713023708.9245-10-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Since the fs-layer file contents encryption implementation was removed,
ext4_bio_write_folio() now always returns 0. Change it to return void,
and likewise for its caller mpage_submit_folio().
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260713023708.9245-9-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
* A major rework of the fast commit mechanism to avoid lock
contention and deadlocks. We also export snapshot statistics
in /proc/fs/ext4/*/fc_info.
* Performance optimization for directory hash computation by
processing input in 4-byte chunks and removing function pointers,
along with new KUnit tests for directory hash.
* Cleanups in JBD2 to remove special slabs and use kmalloc() instead.
* Various bug fixes, including:
- Early validation of donor superblock in EXT4_IOC_MOVE_EXT to avoid
cross-fs deadlock
- Fix for a kernel BUG in ext4_write_inline_data_end under
data=journal
- Fix for a NULL dereference in jbd2_journal_dirty_metadata when
handle is aborted
- Fix for an underflow in JBD2 fast commit block initialization check
- Fix for LOGFLUSH shutdown ordering to ensure ordered data writeback
- Miscellaneous fixes for error path return values and KUnit assertions.
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Merge tag 'ext4_for_linus-7.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
- A major rework of the fast commit mechanism to avoid lock contention
and deadlocks. We also export snapshot statistics in
/proc/fs/ext4/*/fc_info
- Performance optimization for directory hash computation by processing
input in 4-byte chunks and removing function pointers, along with new
KUnit tests for directory hash
- Cleanups in JBD2 to remove special slabs and use kmalloc() instead
- Various bug fixes, including:
- Early validation of donor superblock in EXT4_IOC_MOVE_EXT to
avoid cross-fs deadlock
- Fix for a kernel BUG in ext4_write_inline_data_end under
data=journal
- Fix for a NULL dereference in jbd2_journal_dirty_metadata when
handle is aborted
- Fix for an underflow in JBD2 fast commit block initialization
check
- Fix for LOGFLUSH shutdown ordering to ensure ordered data
writeback
- Miscellaneous fixes for error path return values and KUnit
assertions
* tag 'ext4_for_linus-7.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: validate donor file superblock early in EXT4_IOC_MOVE_EXT
ext4: fix kernel BUG in ext4_write_inline_data_end
ext4: fix ERR_PTR(0) in ext4_mkdir()
jbd2: remove special jbd2 slabs
ext4: remove mention of PageWriteback
ext4: improve str2hashbuf by processing 4-byte chunks and removing function pointers
ext4: add Kunit coverage for directory hash computation
ext4: fast commit: export snapshot stats in fc_info
ext4: fast commit: add lock_updates tracepoint
ext4: fast commit: avoid i_data_sem by dropping ext4_map_blocks() in snapshots
ext4: fast commit: avoid self-deadlock in inode snapshotting
ext4: fast commit: avoid waiting for FC_COMMITTING
ext4: lockdep: handle i_data_sem subclassing for special inodes
ext4: fast commit: snapshot inode state before writing log
jbd2: fix integer underflow in jbd2_journal_initialize_fast_commit()
ext4: fix fast commit wait/wake bit mapping on 64-bit
jbd2: check for aborted handle in jbd2_journal_dirty_metadata()
ext4: Use %pe to print PTR_ERR()
ext4: fix LOGFLUSH shutdown ordering to allow ordered-mode data writeback
ext4: replace KUnit tests for memcmp() with KUNIT_ASSERT_MEMEQ()
Avoid an extra indirect function call and changing the buffer refcount
by converting ext4_end_bitmap_read() from bh_end_io_t to bio_end_io_t
and calling bh_submit().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-13-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: linux-ext4@vger.kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Snapshot-based fast commit can fall back when the commit-time snapshot
cannot be built (e.g. extent status cache misses). It is useful to
quantify the updates-locked window and to see why snapshotting failed.
Add best-effort snapshot counters to the ext4 superblock and extend
/proc/fs/ext4/<sb_id>/fc_info to report the number of snapshotted
inodes and ranges, snapshot failure reasons, and the average/max time
spent with journal updates locked.
Signed-off-by: Li Chen <chenl311@chinatelecom.cn>
Link: https://patch.msgid.link/20260515091829.194810-8-me@linux.beauty
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Commit-time fast commit snapshots run under jbd2_journal_lock_updates(),
so it is useful to quantify the time spent with updates locked and to
understand why snapshotting can fail.
Add a new tracepoint, ext4_fc_lock_updates, reporting the time spent in
the updates-locked window along with the number of snapshotted inodes
and ranges. Record the first snapshot failure reason in a stable snap_err
field for tooling.
Signed-off-by: Li Chen <chenl311@chinatelecom.cn>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://patch.msgid.link/20260515091829.194810-7-me@linux.beauty
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
ext4_fc_track_inode() can be called while holding i_data_sem (e.g.
fallocate). Waiting for EXT4_STATE_FC_COMMITTING in that case risks an
ABBA deadlock: i_data_sem -> wait(FC_COMMITTING) vs FC_COMMITTING ->
wait(i_data_sem) in the commit task.
Now that fast commit snapshots inode state at commit time, updates during
log writing do not need to block. Drop the wait and lockdep assertion in
ext4_fc_track_inode(), and make ext4_fc_del() wait for FC_COMMITTING so an
inode cannot be removed while the commit thread is still using it.
When an inode is modified during a fast commit, mark it with
EXT4_STATE_FC_REQUEUE so cleanup keeps it queued for the next fast commit.
This is needed because jbd2_fc_end_commit() invokes the cleanup callback
with tid == 0, so tid-based requeue logic would requeue every inode.
Testing: tracepoint ext4:ext4_fc_commit_stop with two fsyncs in the same
transaction. nblks is the number of journal blocks written for that fast
commit. Before this change, the second fsync still wrote almost the same
fast commit log (nblks 10->9), because tid == 0 in jbd2_fc_end_commit()
caused the tid-based requeue logic to keep all inodes queued. After this
change, only inodes modified during the commit are requeued, and the
second fsync wrote a nearly empty fast commit (nblks 10->1).
Signed-off-by: Li Chen <chenl311@chinatelecom.cn>
Link: https://patch.msgid.link/20260515091829.194810-4-me@linux.beauty
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Fast commit can hold s_fc_lock while writing journal blocks. Mapping the
journal inode can take its i_data_sem. Normal inode update paths can take a
data inode i_data_sem and then s_fc_lock, which makes lockdep report a
circular dependency.
lockdep treats all i_data_sem instances as one lock class and cannot
distinguish the journal inode i_data_sem from a regular inode i_data_sem.
The journal inode is not tracked by fast commit and no FC waiters ever
depend on it, so this is not a real ABBA deadlock. Assign the journal inode
a dedicated i_data_sem lockdep subclass to avoid the false positive.
Inode cache objects can be recycled, so also reset i_data_sem to
I_DATA_SEM_NORMAL when allocating an ext4 inode. Otherwise a new inode may
inherit an old subclass (journal/quota/ea) and trigger lockdep warnings.
Signed-off-by: Li Chen <chenl311@chinatelecom.cn>
Link: https://patch.msgid.link/20260515091829.194810-3-me@linux.beauty
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Fast commit writes inode metadata and data range updates after unlocking
journal updates. New handles can start at that point, so the log writing
path must not look at live inode state.
Add a commit-time per-inode snapshot and populate it while journal updates
are locked and existing handles are drained. Store the snapshot behind
ext4_inode_info->i_fc_snap so ext4_inode_info only grows by one pointer.
The snapshot contains a copy of the on-disk inode plus the data range
records needed for fast commit TLVs.
Snapshotting runs under jbd2_journal_lock_updates(). Avoid triggering I/O
there by using ext4_get_inode_loc_noio() and falling back to full commit
if the inode table block is not present or not uptodate.
Log writing then only serializes the snapshot, so it no longer needs to
call ext4_map_blocks() and take i_data_sem under s_fc_lock. The snapshot
is installed and freed under s_fc_lock and is released from fast commit
cleanup and inode eviction.
Signed-off-by: Li Chen <chenl311@chinatelecom.cn>
Link: https://patch.msgid.link/20260515091829.194810-2-me@linux.beauty
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
On 64-bit, ext4 dynamic inode states live in the upper half of i_flags,
and ext4_test_inode_state() applies the corresponding +32 offset.
The fast-commit wait and wake paths open-coded the wait key with the raw
EXT4_STATE_* value. Add small helpers for the state wait word and bit,
and use them for the FC_COMMITTING and FC_FLUSHING_DATA waits so the wait
key follows the same mapping as the state helpers.
Fixes: 857d32f261 ("ext4: rework fast commit commit path")
Reported-by: Sashiko AI review <sashiko-bot@kernel.org>
Signed-off-by: Li Chen <chenl311@chinatelecom.cn>
Reviewed-by: Baokun Li <libaokun@linux.alibaba.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260513085818.552432-1-me@linux.beauty
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* Refactor code paths involved with partial block zero-out in
prearation for converting ext4 to use iomap for buffered writes.
* Remove use of d_alloc() from ext4 in preparation for the deprecation
of this interface.
* Replace some J_ASSERTS with a journal abort so we can avoid a kernel
panic for a localized file system error
* Simplify various code paths in mballoc, move_extent, and fast commit
* Fix rare deadlock in jbd2_journal_cancel_revoke() that can be
triggered by generic/013 when blocksize < pagesize.
* Fix memory leak when releasing an extended attribute when its
value is stored in an ea_inode
* Fix various potential kunit test bugs in fs/ext4/extents.c
* Fix potential out-of-bounds access in check_xattr() with a corrupted
file system
* Make the jbd2_inode dirty range tracking safe for lockless reads
* Avoid a WARN_ON when writeback files due to a corrupted file system;
we already print an ext4 warning indicatign that data will be lost,
so the WARN_ON is not necessary and doesn't add any new information
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Merge tag 'ext4_for_linux-7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
- Refactor code paths involved with partial block zero-out in
prearation for converting ext4 to use iomap for buffered writes
- Remove use of d_alloc() from ext4 in preparation for the deprecation
of this interface
- Replace some J_ASSERTS with a journal abort so we can avoid a kernel
panic for a localized file system error
- Simplify various code paths in mballoc, move_extent, and fast commit
- Fix rare deadlock in jbd2_journal_cancel_revoke() that can be
triggered by generic/013 when blocksize < pagesize
- Fix memory leak when releasing an extended attribute when its value
is stored in an ea_inode
- Fix various potential kunit test bugs in fs/ext4/extents.c
- Fix potential out-of-bounds access in check_xattr() with a corrupted
file system
- Make the jbd2_inode dirty range tracking safe for lockless reads
- Avoid a WARN_ON when writeback files due to a corrupted file system;
we already print an ext4 warning indicatign that data will be lost,
so the WARN_ON is not necessary and doesn't add any new information
* tag 'ext4_for_linux-7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (37 commits)
jbd2: fix deadlock in jbd2_journal_cancel_revoke()
ext4: fix missing brelse() in ext4_xattr_inode_dec_ref_all()
ext4: fix possible null-ptr-deref in mbt_kunit_exit()
ext4: fix possible null-ptr-deref in extents_kunit_exit()
ext4: fix the error handling process in extents_kunit_init).
ext4: call deactivate_super() in extents_kunit_exit()
ext4: fix miss unlock 'sb->s_umount' in extents_kunit_init()
ext4: fix bounds check in check_xattrs() to prevent out-of-bounds access
ext4: zero post-EOF partial block before appending write
ext4: move pagecache_isize_extended() out of active handle
ext4: remove ctime/mtime update from ext4_alloc_file_blocks()
ext4: unify SYNC mode checks in fallocate paths
ext4: ensure zeroed partial blocks are persisted in SYNC mode
ext4: move zero partial block range functions out of active handle
ext4: pass allocate range as loff_t to ext4_alloc_file_blocks()
ext4: remove handle parameters from zero partial block functions
ext4: move ordered data handling out of ext4_block_do_zero_range()
ext4: rename ext4_block_zero_page_range() to ext4_block_zero_range()
ext4: factor out journalled block zeroing range
ext4: rename and extend ext4_block_truncate_page()
...
Please consider pulling these changes from the signed vfs-7.1-rc1.bh.metadata tag.
Thanks!
Christian
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Merge tag 'vfs-7.1-rc1.bh.metadata' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs buffer_head updates from Christian Brauner:
"This cleans up the mess that has accumulated over the years in
metadata buffer_head tracking for inodes.
It moves the tracking into dedicated structure in filesystem-private
part of the inode (so that we don't use private_list, private_data,
and private_lock in struct address_space), and also moves couple other
users of private_data and private_list so these are removed from
struct address_space saving 3 longs in struct inode for 99% of inodes"
* tag 'vfs-7.1-rc1.bh.metadata' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (42 commits)
fs: Drop i_private_list from address_space
fs: Drop mapping_metadata_bhs from address space
ext4: Track metadata bhs in fs-private inode part
minix: Track metadata bhs in fs-private inode part
udf: Track metadata bhs in fs-private inode part
fat: Track metadata bhs in fs-private inode part
bfs: Track metadata bhs in fs-private inode part
affs: Track metadata bhs in fs-private inode part
ext2: Track metadata bhs in fs-private inode part
fs: Provide functions for handling mapping_metadata_bhs directly
fs: Switch inode_has_buffers() to take mapping_metadata_bhs
fs: Make bhs point to mapping_metadata_bhs
fs: Move metadata bhs tracking to a separate struct
fs: Fold fsync_buffers_list() into sync_mapping_buffers()
fs: Drop osync_buffers_list()
kvm: Use private inode list instead of i_private_list
fs: Remove i_private_data
aio: Stop using i_private_data and i_private_lock
hugetlbfs: Stop using i_private_data
fs: Stop using i_private_data for metadata bh tracking
...
Please consider pulling these changes from the signed vfs-7.1-rc1.kino tag.
Thanks!
Christian
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Merge tag 'vfs-7.1-rc1.kino' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs i_ino updates from Christian Brauner:
"For historical reasons, the inode->i_ino field is an unsigned long,
which means that it's 32 bits on 32 bit architectures. This has caused
a number of filesystems to implement hacks to hash a 64-bit identifier
into a 32-bit field, and deprives us of a universal identifier field
for an inode.
This changes the inode->i_ino field from an unsigned long to a u64.
This shouldn't make any material difference on 64-bit hosts, but
32-bit hosts will see struct inode grow by at least 4 bytes. This
could have effects on slabcache sizes and field alignment.
The bulk of the changes are to format strings and tracepoints, since
the kernel itself doesn't care that much about the i_ino field. The
first patch changes some vfs function arguments, so check that one out
carefully.
With this change, we may be able to shrink some inode structures. For
instance, struct nfs_inode has a fileid field that holds the 64-bit
inode number. With this set of changes, that field could be
eliminated. I'd rather leave that sort of cleanups for later just to
keep this simple"
* tag 'vfs-7.1-rc1.kino' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
nilfs2: fix 64-bit division operations in nilfs_bmap_find_target_in_group()
EVM: add comment describing why ino field is still unsigned long
vfs: remove externs from fs.h on functions modified by i_ino widening
treewide: fix missed i_ino format specifier conversions
ext4: fix signed format specifier in ext4_load_inode trace event
treewide: change inode->i_ino from unsigned long to u64
nilfs2: widen trace event i_ino fields to u64
f2fs: widen trace event i_ino fields to u64
ext4: widen trace event i_ino fields to u64
zonefs: widen trace event i_ino fields to u64
hugetlbfs: widen trace event i_ino fields to u64
ext2: widen trace event i_ino fields to u64
cachefiles: widen trace event i_ino fields to u64
vfs: widen trace event i_ino fields to u64
net: change sock.sk_ino and sock_i_ino() to u64
audit: widen ino fields to u64
vfs: widen inode hash/lookup functions to u64
In ext4_zero_range() and ext4_punch_hole(), when operating in SYNC mode
and zeroing a partial block, only data=journal modes guarantee that the
zeroed data is synchronously persisted after the operation completes.
For data=ordered/writeback mode and non-journal modes, this guarantee is
missing.
Introduce a partial_zero parameter to explicitly trigger writeback for
all scenarios where a partial block is zeroed, ensuring the zeroed data
is durably persisted.
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20260327102939.1095257-10-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Only journal data mode requires an active journal handle when zeroing
partial blocks. Stop passing handle_t *handle to
ext4_zero_partial_blocks() and related functions, and make
ext4_block_journalled_zero_range() start a handle independently.
This change has no practical impact now because all callers invoke these
functions within the context of an active handle. It prepares for moving
ext4_block_zero_eof() out of an active handle in the next patch, which
is a prerequisite for converting block zero range operations to iomap
infrastructure.
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260327102939.1095257-7-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Rename ext4_block_truncate_page() to ext4_block_zero_eof() and extend
its signature to accept an explicit 'end' offset instead of calculating
the block boundary. This helper function now can replace all cases
requiring zeroing of the partial EOF block, including the append
buffered write paths in ext4_*_write_end().
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260327102939.1095257-3-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
__ext4_link() has two callers.
- ext4_link() calls it during normal handling of the link() system
call or similar
- ext4_fc_replay_link_internal() calls it when replaying the journal
at mount time.
The former needs changes to dcache - instantiating the dentry to the
inode on success. The latter doesn't need or want any dcache
manipulation.
So move the manipulation out of __ext4_link() and do it in ext4_link()
only.
This requires:
- passing the qname from the dentry explicitly to __ext4_link.
The parent dir is already passed. The dentry is still passed
in the ext4_link() case purely for use by ext4_fc_track_link().
- passing the inode separately to ext4_fc_track_link() as the
dentry will not be instantiated yet.
- using __ext4_add_entry() in ext4_link, which doesn't need a dentry.
- moving ihold(), d_instantiate(), drop_nlink() and iput() calls out
of __ext4_link() into ext4_link().
Note that ext4_inc_count() and drop_nlink() remain in __ext4_link()
as both callers need them and they are not related to the dentry.
This substantially simplifies ext4_fc_replay_link_internal(), and
removes a use of d_alloc() which, it is planned, will be removed.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://patch.msgid.link/20260320000838.3797494-4-neilb@ownmail.net
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
i_fc_wait is only initialized in ext4_fc_init_inode() and never used for
waiting or wakeups. Drop it.
Signed-off-by: Li Chen <me@linux.beauty>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20260120121941.144192-1-me@linux.beauty
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Commit b98535d091 ("ext4: fix bug_on in start_this_handle during umount
filesystem") moved ext4_unregister_sysfs() before flushing s_sb_upd_work
to prevent new error work from being queued via /proc/fs/ext4/xx/mb_groups
reads during unmount. However, this introduced a use-after-free because
update_super_work calls ext4_notify_error_sysfs() -> sysfs_notify() which
accesses the kobject's kernfs_node after it has been freed by kobject_del()
in ext4_unregister_sysfs():
update_super_work ext4_put_super
----------------- --------------
ext4_unregister_sysfs(sb)
kobject_del(&sbi->s_kobj)
__kobject_del()
sysfs_remove_dir()
kobj->sd = NULL
sysfs_put(sd)
kernfs_put() // RCU free
ext4_notify_error_sysfs(sbi)
sysfs_notify(&sbi->s_kobj)
kn = kobj->sd // stale pointer
kernfs_get(kn) // UAF on freed kernfs_node
ext4_journal_destroy()
flush_work(&sbi->s_sb_upd_work)
Instead of reordering the teardown sequence, fix this by making
ext4_notify_error_sysfs() detect that sysfs has already been torn down
by checking s_kobj.state_in_sysfs, and skipping the sysfs_notify() call
in that case. A dedicated mutex (s_error_notify_mutex) serializes
ext4_notify_error_sysfs() against kobject_del() in ext4_unregister_sysfs()
to prevent TOCTOU races where the kobject could be deleted between the
state_in_sysfs check and the sysfs_notify() call.
Fixes: b98535d091 ("ext4: fix bug_on in start_this_handle during umount filesystem")
Cc: Jiayuan Chen <jiayuan.chen@linux.dev>
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jiayuan Chen <jiayuan.chen@shopee.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260319120336.157873-1-jiayuan.chen@linux.dev
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Track metadata bhs for an inode in fs-private part of the inode. We need
the tracking only for nojournal mode so this is somewhat wasteful. We
can relatively easily make the mapping_metadata_bhs struct dynamically
allocated similarly to how we treat jbd2_inode but let's leave that for
ext4 specific series once the dust settles a bit.
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260326095354.16340-82-jack@suse.cz
Signed-off-by: Christian Brauner <brauner@kernel.org>
On 32-bit architectures, unsigned long is only 32 bits wide, which
causes 64-bit inode numbers to be silently truncated. Several
filesystems (NFS, XFS, BTRFS, etc.) can generate inode numbers that
exceed 32 bits, and this truncation can lead to inode number collisions
and other subtle bugs on 32-bit systems.
Change the type of inode->i_ino from unsigned long to u64 to ensure that
inode numbers are always represented as 64-bit values regardless of
architecture. Update all format specifiers treewide from %lu/%lx to
%llu/%llx to match the new type, along with corresponding local variable
types.
This is the bulk treewide conversion. Earlier patches in this series
handled trace events separately to allow trace field reordering for
better struct packing on 32-bit.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20260304-iino-u64-v3-12-2257ad83d372@kernel.org
Acked-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
fsverity cleanups, speedup, and memory usage optimization from
Christoph Hellwig:
- Move some logic into common code
- Fix btrfs to reject truncates of fsverity files
- Improve the readahead implementation
- Store each inode's fsverity_info in a hash table instead of using a
pointer in the filesystem-specific part of the inode.
This optimizes for memory usage in the usual case where most files
don't have fsverity enabled.
- Look up the fsverity_info fewer times during verification, to
amortize the hash table overhead
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Merge tag 'fsverity-for-linus' of git://git.kernel.org/pub/scm/fs/fsverity/linux
Pull fsverity updates from Eric Biggers:
"fsverity cleanups, speedup, and memory usage optimization from
Christoph Hellwig:
- Move some logic into common code
- Fix btrfs to reject truncates of fsverity files
- Improve the readahead implementation
- Store each inode's fsverity_info in a hash table instead of using a
pointer in the filesystem-specific part of the inode.
This optimizes for memory usage in the usual case where most files
don't have fsverity enabled.
- Look up the fsverity_info fewer times during verification, to
amortize the hash table overhead"
* tag 'fsverity-for-linus' of git://git.kernel.org/pub/scm/fs/fsverity/linux:
fsverity: remove inode from fsverity_verification_ctx
fsverity: use a hashtable to find the fsverity_info
btrfs: consolidate fsverity_info lookup
f2fs: consolidate fsverity_info lookup
ext4: consolidate fsverity_info lookup
fs: consolidate fsverity_info lookup in buffer.c
fsverity: push out fsverity_info lookup
fsverity: deconstify the inode pointer in struct fsverity_info
fsverity: kick off hash readahead at data I/O submission time
ext4: move ->read_folio and ->readahead to readpage.c
readahead: push invalidate_lock out of page_cache_ra_unbounded
fsverity: don't issue readahead for non-ENOENT errors from __filemap_get_folio
fsverity: start consolidating pagecache code
fsverity: pass struct file to ->write_merkle_tree_block
f2fs: don't build the fsverity work handler for !CONFIG_FS_VERITY
ext4: don't build the fsverity work handler for !CONFIG_FS_VERITY
fs,fsverity: clear out fsverity_info from common code
fs,fsverity: reject size changes on fsverity files in setattr_prepare
* Avoid unnecessary cache invadiation in the extent status cache
(es_cache) when adding extents to be cached in the es_cache and we
are not changing the extent tree.
* Add a sysfs parameter, err_report_sec, to control how frequently
to log a warning message that file system inconsistency has been
detected. (Previously we logged the warning message every 24
hours.)
* Avoid unnecessary forced ordered writes when appending to a file
when delayed allocation is enabled.
* Defer splitting unwritten extents to I/O completion to improve
write performance of concurrent direct I/O writes to multiple
files.
* Refactor and add kunit tests to the extent splitting and
conversion code paths.
Various Bug Fixes
* Fix a panic when the debugging DOUBLE_CHECK macro is defined.
* Avoid using fast commit for rare and complex file system
operations to make fast commit easier to reason about. This can
also avoid some corner cases that could result in file system
inconsistency if there is a crash between the fast commit before a
subsequent full commit.
* Fix memory leaks in error paths
* Fix a false positive reports caused when running stress tests
using mixed huge-page workloads caused by a race between page
migration and bitmap updates.
* Fix a potential recursion into file system reclaim when evicting
an inode when fast commit is enabled.
* Fix a warning caused by a potential double decrement to the dirty
clusters counter when executing FS_IOC_SHUTDOWN when running a
stress test.
* Enable mballoc optimzied scanning regardless whether the inode is
using indirect blocks or extent trees to map blocks.
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Merge tag 'ext4_for_linus-7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
"New features and improvements for the ext4 file system
- Avoid unnecessary cache invalidation in the extent status cache
(es_cache) when adding extents to be cached in the es_cache and we
are not changing the extent tree
- Add a sysfs parameter, err_report_sec, to control how frequently to
log a warning message that file system inconsistency has been
detected (Previously we logged the warning message every 24 hours)
- Avoid unnecessary forced ordered writes when appending to a file
when delayed allocation is enabled
- Defer splitting unwritten extents to I/O completion to improve
write performance of concurrent direct I/O writes to multiple files
- Refactor and add kunit tests to the extent splitting and conversion
code paths
Various Bug Fixes:
- Fix a panic when the debugging DOUBLE_CHECK macro is defined
- Avoid using fast commit for rare and complex file system operations
to make fast commit easier to reason about. This can also avoid
some corner cases that could result in file system inconsistency if
there is a crash between the fast commit before a subsequent full
commit
- Fix memory leaks in error paths
- Fix a false positive reports caused when running stress tests using
mixed huge-page workloads caused by a race between page migration
and bitmap updates
- Fix a potential recursion into file system reclaim when evicting an
inode when fast commit is enabled
- Fix a warning caused by a potential double decrement to the dirty
clusters counter when executing FS_IOC_SHUTDOWN when running a
stress test
- Enable mballoc optimized scanning regardless whether the inode is
using indirect blocks or extent trees to map blocks"
* tag 'ext4_for_linus-7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (45 commits)
et4: allow zeroout when doing written to unwritten split
ext4: refactor split and convert extents
ext4: refactor zeroout path and handle all cases
ext4: propagate flags to ext4_convert_unwritten_extents_endio()
ext4: propagate flags to convert_initialized_extent()
ext4: add extent status cache support to kunit tests
ext4: kunit tests for higher level extent manipulation functions
ext4: kunit tests for extent splitting and conversion
ext4: use optimized mballoc scanning regardless of inode format
ext4: always allocate blocks only from groups inode can use
ext4: fix dirtyclusters double decrement on fs shutdown
ext4: fast commit: make s_fc_lock reclaim-safe
ext4: fix e4b bitmap inconsistency reports
ext4: remove redundant NULL check after __GFP_NOFAIL
ext4: remove EXT4_GET_BLOCKS_IO_CREATE_EXT
ext4: simplify the mapping query logic in ext4_iomap_begin()
ext4: remove unused unwritten parameter in ext4_dio_write_iter()
ext4: remove useless ext4_iomap_overwrite_ops
ext4: avoid starting handle when dio writing an unwritten extent
ext4: don't split extent before submitting I/O
...
Use the kernel's resizable hash table (rhashtable) to find the
fsverity_info. This way file systems that want to support fsverity don't
have to bloat every inode in the system with an extra pointer. The
trade-off is that looking up the fsverity_info is a bit more expensive
now, but the main operations are still dominated by I/O and hashing
overhead.
The rhashtable implementations requires no external synchronization, and
the _fast versions of the APIs provide the RCU critical sections required
by the implementation. Because struct fsverity_info is only removed on
inode eviction and does not contain a reference count, there is no need
for an extended critical section to grab a reference or validate the
object state. The file open path uses rhashtable_lookup_get_insert_fast,
which can either find an existing object for the hash key or insert a
new one in a single atomic operation, so that concurrent opens never
instantiate duplicate fsverity_info structure. FS_IOC_ENABLE_VERITY must
already be synchronized by a combination of i_rwsem and file system flags
and uses rhashtable_lookup_insert_fast, which errors out on an existing
object for the hash key as an additional safety check.
Because insertion into the hash table now happens before S_VERITY is set,
fsverity just becomes a barrier and a flag check and doesn't have to look
up the fsverity_info at all, so there is only a single lookup per
->read_folio or ->readahead invocation. For btrfs there is an additional
one for each bio completion, while for ext4 and f2fs the fsverity_info
is stored in the per-I/O context and reused for the completion workqueue.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Link: https://lore.kernel.org/r/20260202060754.270269-12-hch@lst.de
[EB: folded in fix for missing fsverity_free_info()]
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Keep all the read into pagecache code in a single file.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20260202060754.270269-4-hch@lst.de
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Add more kunit tests to cover the high level caller
ext4_map_create_blocks(). We pass flags in a manner that covers
the below function:
1. ext4_ext_handle_unwritten_extents()
1.1 - Split/Convert unwritten extent to written in endio convtext.
1.2 - Split/Convert unwritten extent to written in non endio context.
1.3 - Zeroout tests for the above 2 cases
2. convert_initialized_extent() - Convert written extent to unwritten
during zero range
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Link: https://patch.msgid.link/9d8ad32cb62f44999c0fe3545b44fc3113546c70.1769149131.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
s_fc_lock can be acquired from inode eviction and thus is
reclaim unsafe. Since the fast commit path holds s_fc_lock while writing
the commit log, allocations under the lock can enter reclaim and invert
the lock order with fs_reclaim. Add ext4_fc_lock()/ext4_fc_unlock()
helpers which acquire s_fc_lock under memalloc_nofs_save()/restore()
context and use them everywhere so allocations under the lock cannot
recurse into filesystem reclaim.
Fixes: 6593714d67 ("ext4: hold s_fc_lock while during fast commit")
Signed-off-by: Li Chen <me@linux.beauty>
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260106120621.440126-1-me@linux.beauty
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
We do not use EXT4_GET_BLOCKS_IO_CREATE_EXT or split extents before
submitting I/O; therefore, remove the related code.
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Link: https://patch.msgid.link/20260105014522.1937690-8-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
ext4_iomap_overwrite_ops was introduced in commit 8cd115bdda ("ext4:
Optimize ext4 DIO overwrites"), which can optimize pure overwrite
performance by dropping the IOMAP_WRITE flag to only query the mapped
mapping information. This avoids starting a new journal handle, thereby
improving speed. Later, commit 9faac62d40 ("ext4: optimize file
overwrites") also optimized similar scenarios, but it performs the check
later, examining the mappings status only when the actual block mapping
is needed. Thus, it can handle the previous commit scenario. That means
in the case of an overwrite scenario, the condition
"offset + length <= i_size_read(inode)" in the write path must always be
true.
Therefore, it is acceptable to remove the ext4_iomap_overwrite_ops,
which will also clarify the write and read paths of ext4_iomap_begin.
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Link: https://patch.msgid.link/20260105014522.1937690-5-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Add a new sysfs attribute "err_report_sec" to control the s_err_report
timer in ext4_sb_info. Writing '0' disables the timer, while writing
a non-zero value enables the timer and sets the timeout in seconds.
Signed-off-by: Baolin Liu <liubaolin@kylinos.cn>
Link: https://patch.msgid.link/20251211030256.28613-1-liubaolin12138@163.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Stop definining these privately and instead move them to the uapi
errno.h so that they become canonical instead of copy pasta.
Cc: linux-api@vger.kernel.org
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Link: https://patch.msgid.link/176826402587.3490369.17659117524205214600.stgit@frogsfrogsfrogs
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Supporting a block size greater than the page size (BS > PS) requires
support for large folios. However, several features (e.g., encrypt)
do not yet support large folios.
To prevent conflicts, this patch adds checks at mount time to prohibit
these features from being used when BS > PS. Since these features cannot
be changed on remount, there is no need to check on remount.
This patch adds s_max_folio_order, initialized during mount according to
filesystem features and mount options. If s_max_folio_order is 0, large
folios are disabled.
With this in place, ext4_set_inode_mapping_order() can be simplified by
checking s_max_folio_order, avoiding redundant checks.
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Message-ID: <20251121090654.631996-24-libaokun@huaweicloud.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
As BS > PS support is coming, all block number to page index (and
vice-versa) conversions must now go via bytes. Added EXT4_LBLK_TO_PG()
and EXT4_PG_TO_LBLK() macros to simplify these conversions and handle
both BS <= PS and BS > PS scenarios cleanly.
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Message-ID: <20251121090654.631996-11-libaokun@huaweicloud.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
