While reviewing recent ext4 patch[1], Sashiko raised the following
concern[2]:
> If the filesystem is initially mounted with the discard option,
> deleting files will populate sbi->s_discard_list and queue
> s_discard_work. If it is then remounted with nodiscard, the
> EXT4_MOUNT_DISCARD flag is cleared, but the pending s_discard_work is
> neither cancelled nor flushed.
[1] https://lore.kernel.org/r/20260319094545.19291-1-qiang.zhang@linux.dev/
[2] https://sashiko.dev/#/patchset/20260319094545.19291-1-qiang.zhang%40linux.dev
The concern was valid, but it had nothing to do with the patch[1].
One of the problems with Sashiko in its current (early) form is that
it will detect pre-existing issues and report it as a problem with the
patch that it is reviewing.
In practice, it would be hard to hit deliberately (unless you are a
malicious syzkaller fuzzer), since it would involve mounting the file
system with -o discard, and then deleting a large number of files,
remounting the file system with -o nodiscard, and then immediately
unmounting the file system before the queued discard work has a change
to drain on its own.
Fix it because it's a real bug, and to avoid Sashiko from raising this
concern when analyzing future patches to mballoc.c.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Fixes: 55cdd0af2b ("ext4: get discard out of jbd2 commit kthread contex")
Cc: stable@kernel.org
Commit 4865c768b5 ("ext4: always allocate blocks only from groups
inode can use") restricts what blocks will be allocated for indirect
block based files to block numbers that fit within 32-bit block
numbers.
However, when using a review bot running on the latest Gemini LLM to
check this commit when backporting into an LTS based kernel, it raised
this concern:
If ac->ac_g_ex.fe_group is >= ngroups (for instance, if the goal
group was populated via stream allocation from s_mb_last_groups),
then start will be >= ngroups.
Does this allow allocating blocks beyond the 32-bit limit for
indirect block mapped files? The commit message mentions that
ext4_mb_scan_groups_linear() takes care to not select unsupported
groups. However, its loop uses group = *start, and the very first
iteration will call ext4_mb_scan_group() with this unsupported
group because next_linear_group() is only called at the end of the
iteration.
After reviewing the code paths involved and considering the LLM
review, I determined that this can happen when there is a file system
where some files/directories are extent-mapped and others are
indirect-block mapped. To address this, add a safety clamp in
ext4_mb_scan_groups().
Fixes: 4865c768b5 ("ext4: always allocate blocks only from groups inode can use")
Cc: Jan Kara <jack@suse.cz>
Reviewed-by: Baokun Li <libaokun@linux.alibaba.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Link: https://patch.msgid.link/20260326045834.1175822-1-tytso@mit.edu
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
There's issue as follows:
...
EXT4-fs (mmcblk0p1): Delayed block allocation failed for inode 206 at logical offset 0 with max blocks 1 with error 117
EXT4-fs (mmcblk0p1): This should not happen!! Data will be lost
EXT4-fs (mmcblk0p1): Delayed block allocation failed for inode 206 at logical offset 0 with max blocks 1 with error 117
EXT4-fs (mmcblk0p1): This should not happen!! Data will be lost
EXT4-fs (mmcblk0p1): Delayed block allocation failed for inode 206 at logical offset 0 with max blocks 1 with error 117
EXT4-fs (mmcblk0p1): This should not happen!! Data will be lost
EXT4-fs (mmcblk0p1): Delayed block allocation failed for inode 206 at logical offset 0 with max blocks 1 with error 117
EXT4-fs (mmcblk0p1): This should not happen!! Data will be lost
EXT4-fs (mmcblk0p1): Delayed block allocation failed for inode 2243 at logical offset 0 with max blocks 1 with error 117
EXT4-fs (mmcblk0p1): This should not happen!! Data will be lost
EXT4-fs (mmcblk0p1): Delayed block allocation failed for inode 2239 at logical offset 0 with max blocks 1 with error 117
EXT4-fs (mmcblk0p1): This should not happen!! Data will be lost
EXT4-fs (mmcblk0p1): error count since last fsck: 1
EXT4-fs (mmcblk0p1): initial error at time 1765597433: ext4_mb_generate_buddy:760
EXT4-fs (mmcblk0p1): last error at time 1765597433: ext4_mb_generate_buddy:760
...
According to the log analysis, blocks are always requested from the
corrupted block group. This may happen as follows:
ext4_mb_find_by_goal
ext4_mb_load_buddy
ext4_mb_load_buddy_gfp
ext4_mb_init_cache
ext4_read_block_bitmap_nowait
ext4_wait_block_bitmap
ext4_validate_block_bitmap
if (!grp || EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
return -EFSCORRUPTED; // There's no logs.
if (err)
return err; // Will return error
ext4_lock_group(ac->ac_sb, group);
if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info))) // Unreachable
goto out;
After commit 9008a58e5d ("ext4: make the bitmap read routines return
real error codes") merged, Commit 163a203ddb ("ext4: mark block group
as corrupt on block bitmap error") is no real solution for allocating
blocks from corrupted block groups. This is because if
'EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info)' is true, then
'ext4_mb_load_buddy()' may return an error. This means that the block
allocation will fail.
Therefore, check block group if corrupted when ext4_mb_load_buddy()
returns error.
Fixes: 163a203ddb ("ext4: mark block group as corrupt on block bitmap error")
Fixes: 9008a58e5d ("ext4: make the bitmap read routines return real error codes")
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260302134619.3145520-1-yebin@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
This was done entirely with mindless brute force, using
git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'
to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.
Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.
For the same reason the 'flex' versions will be done as a separate
conversion.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
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
...
Currently we don't used mballoc optimized scanning (using max free
extent order and avg free extent order group lists) for inodes with
indirect block based format. This is confusing for users and I don't see
a good reason for that. Even with indirect block based inode format we
can spend big amount of time searching for free blocks for large
filesystems with fragmented free space. To add to the confusion before
commit 077d0c2c78 ("ext4: make mb_optimize_scan performance mount
option work with extents") optimized scanning was applied *only* to
indirect block based inodes so that commit appears as a performance
regression to some users. Just use optimized scanning whenever it is
enabled by mount options.
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: stable@kernel.org
Link: https://patch.msgid.link/20260114182836.14120-4-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
For filesystems with more than 2^32 blocks inodes using indirect block
based format cannot use blocks beyond the 32-bit limit.
ext4_mb_scan_groups_linear() takes care to not select these unsupported
groups for such inodes however other functions selecting groups for
allocation don't. So far this is harmless because the other selection
functions are used only with mb_optimize_scan and this is currently
disabled for inodes with indirect blocks however in the following patch
we want to enable mb_optimize_scan regardless of inode format.
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Pedro Falcato <pfalcato@suse.de>
Cc: stable@kernel.org
Link: https://patch.msgid.link/20260114182836.14120-3-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
fstests test generic/388 occasionally reproduces a warning in
ext4_put_super() associated with the dirty clusters count:
WARNING: CPU: 7 PID: 76064 at fs/ext4/super.c:1324 ext4_put_super+0x48c/0x590 [ext4]
Tracing the failure shows that the warning fires due to an
s_dirtyclusters_counter value of -1. IOW, this appears to be a
spurious decrement as opposed to some sort of leak. Further tracing
of the dirty cluster count deltas and an LLM scan of the resulting
output identified the cause as a double decrement in the error path
between ext4_mb_mark_diskspace_used() and the caller
ext4_mb_new_blocks().
First, note that generic/388 is a shutdown vs. fsstress test and so
produces a random set of operations and shutdown injections. In the
problematic case, the shutdown triggers an error return from the
ext4_handle_dirty_metadata() call(s) made from
ext4_mb_mark_context(). The changed value is non-zero at this point,
so ext4_mb_mark_diskspace_used() does not exit after the error
bubbles up from ext4_mb_mark_context(). Instead, the former
decrements both cluster counters and returns the error up to
ext4_mb_new_blocks(). The latter falls into the !ar->len out path
which decrements the dirty clusters counter a second time, creating
the inconsistency.
To avoid this problem and simplify ownership of the cluster
reservation in this codepath, lift the counter reduction to a single
place in the caller. This makes it more clear that
ext4_mb_new_blocks() is responsible for acquiring cluster
reservation (via ext4_claim_free_clusters()) in the !delalloc case
as well as releasing it, regardless of whether it ends up consumed
or returned due to failure.
Fixes: 0087d9fb3f ("ext4: Fix s_dirty_blocks_counter if block allocation failed with nodelalloc")
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Link: https://patch.msgid.link/20260113171905.118284-1-bfoster@redhat.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
A bitmap inconsistency issue was observed during stress tests under
mixed huge-page workloads. Ext4 reported multiple e4b bitmap check
failures like:
ext4_mb_complex_scan_group:2508: group 350, 8179 free clusters as
per group info. But got 8192 blocks
Analysis and experimentation confirmed that the issue is caused by a
race condition between page migration and bitmap modification. Although
this timing window is extremely narrow, it is still hit in practice:
folio_lock ext4_mb_load_buddy
__migrate_folio
check ref count
folio_mc_copy __filemap_get_folio
folio_try_get(folio)
......
mb_mark_used
ext4_mb_unload_buddy
__folio_migrate_mapping
folio_ref_freeze
folio_unlock
The root cause of this issue is that the fast path of load_buddy only
increments the folio's reference count, which is insufficient to prevent
concurrent folio migration. We observed that the folio migration process
acquires the folio lock. Therefore, we can determine whether to take the
fast path in load_buddy by checking the lock status. If the folio is
locked, we opt for the slow path (which acquires the lock) to close this
concurrency window.
Additionally, this change addresses the following issues:
When the DOUBLE_CHECK macro is enabled to inspect bitmap-related
issues, the following error may be triggered:
corruption in group 324 at byte 784(6272): f in copy != ff on
disk/prealloc
Analysis reveals that this is a false positive. There is a specific race
window where the bitmap and the group descriptor become momentarily
inconsistent, leading to this error report:
ext4_mb_load_buddy ext4_mb_load_buddy
__filemap_get_folio(create|lock)
folio_lock
ext4_mb_init_cache
folio_mark_uptodate
__filemap_get_folio(no lock)
......
mb_mark_used
mb_mark_used_double
mb_cmp_bitmaps
mb_set_bits(e4b->bd_bitmap)
folio_unlock
The original logic assumed that since mb_cmp_bitmaps is called when the
bitmap is newly loaded from disk, the folio lock would be sufficient to
prevent concurrent access. However, this overlooks a specific race
condition: if another process attempts to load buddy and finds the folio
is already in an uptodate state, it will immediately begin using it without
holding folio lock.
Signed-off-by: Yongjian Sun <sunyongjian1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260106090820.836242-1-sunyongjian@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
min_t(unsigned int, a, b) casts an 'unsigned long' to 'unsigned int'.
Use min(a, b) instead as it promotes any 'unsigned int' to 'unsigned long'
and so cannot discard significant bits.
A couple of places need umin() because of loops like:
nfolios = DIV_ROUND_UP(ret + start, PAGE_SIZE);
for (i = 0; i < nfolios; i++) {
struct folio *folio = page_folio(pages[i]);
...
unsigned int len = umin(ret, PAGE_SIZE - start);
...
ret -= len;
...
}
where the compiler doesn't track things well enough to know that
'ret' is never negative.
The alternate loop:
for (i = 0; ret > 0; i++) {
struct folio *folio = page_folio(pages[i]);
...
unsigned int len = min(ret, PAGE_SIZE - start);
...
ret -= len;
...
}
would be equivalent and doesn't need 'nfolios'.
Most of the 'unsigned long' actually come from PAGE_SIZE.
Detected by an extra check added to min_t().
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Link: https://patch.msgid.link/20251119224140.8616-31-david.laight.linux@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
We use EXT4_BAD_INO for the buddy cache inode number. This inode is not
accessed via __ext4_new_inode() or __ext4_iget(), meaning
ext4_set_inode_mapping_order() is not called to set its folio order range.
However, future block size greater than page size support requires this
inode to support large folios, and the buddy cache code already handles
BS > PS. Therefore, ext4_set_inode_mapping_order() is now explicitly
called for this specific inode to set its folio order range.
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: <20251121090654.631996-15-libaokun@huaweicloud.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Currently, ext4_mb_init_cache() uses blocks_per_page to calculate the
folio index and offset. However, when blocksize is larger than PAGE_SIZE,
blocks_per_page becomes zero, leading to a potential division-by-zero bug.
Since we now have the folio, we know its exact size. This allows us to
convert {blocks, groups}_per_page to {blocks, groups}_per_folio, thus
supporting block sizes greater than page size.
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: <20251121090654.631996-14-libaokun@huaweicloud.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Currently, ext4_mb_get_buddy_page_lock() uses blocks_per_page to calculate
folio index and offset. However, when blocksize is larger than PAGE_SIZE,
blocks_per_page becomes zero, leading to a potential division-by-zero bug.
To support BS > PS, use bytes to compute folio index and offset within
folio to get rid of blocks_per_page.
Also, since ext4_mb_get_buddy_page_lock() already fully supports folio,
rename it to ext4_mb_get_buddy_folio_lock().
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: <20251121090654.631996-13-libaokun@huaweicloud.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Currently, ext4_mb_load_buddy_gfp() uses blocks_per_page to calculate the
folio index and offset. However, when blocksize is larger than PAGE_SIZE,
blocks_per_page becomes zero, leading to a potential division-by-zero bug.
To support BS > PS, use bytes to compute folio index and offset within
folio to get rid of blocks_per_page.
Also, if buddy and bitmap land in the same folio, we get that folio’s ref
instead of looking it up again before updating the buddy.
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: <20251121090654.631996-12-libaokun@huaweicloud.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
When the MB_CHECK_ASSERT macro is enabled, we found that the
current validation logic in __mb_check_buddy has a gap in
detecting certain invalid buddy states, particularly related
to order-0 (bitmap) bits.
The original logic consists of three steps:
1. Validates higher-order buddies: if a higher-order bit is
set, at most one of the two corresponding lower-order bits
may be free; if a higher-order bit is clear, both lower-order
bits must be allocated (and their bitmap bits must be 0).
2. For any set bit in order-0, ensures all corresponding
higher-order bits are not free.
3. Verifies that all preallocated blocks (pa) in the group
have pa_pstart within bounds and their bitmap bits marked as
allocated.
However, this approach fails to properly validate cases where
order-0 bits are incorrectly cleared (0), allowing some invalid
configurations to pass:
corrupt integral
order 3 1 1
order 2 1 1 1 1
order 1 1 1 1 1 1 1 1 1
order 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1
Here we get two adjacent free blocks at order-0 with inconsistent
higher-order state, and the right one shows the correct scenario.
The root cause is insufficient validation of order-0 zero bits.
To fix this and improve completeness without significant performance
cost, we refine the logic:
1. Maintain the top-down higher-order validation, but we no longer
check the cases where the higher-order bit is 0, as this case will
be covered in step 2.
2. Enhance order-0 checking by examining pairs of bits:
- If either bit in a pair is set (1), all corresponding
higher-order bits must not be free.
- If both bits are clear (0), then exactly one of the
corresponding higher-order bits must be free
3. Keep the preallocation (pa) validation unchanged.
This change closes the validation gap, ensuring illegal buddy states
involving order-0 are correctly detected, while removing redundant
checks and maintaining efficiency.
Fixes: c9de560ded ("ext4: Add multi block allocator for ext4")
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Yongjian Sun <sunyongjian1@huawei.com>
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Message-ID: <20251106060614.631382-3-sunyongjian@huaweicloud.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
When the MB_CHECK_ASSERT macro is enabled, an assertion failure can
occur in __mb_check_buddy when checking preallocated blocks (pa) in
a block group:
Assertion failure in mb_free_blocks() : "groupnr == e4b->bd_group"
This happens when a pa at the very end of a block group (e.g.,
pa_pstart=32765, pa_len=3 in a group of 32768 blocks) becomes
exhausted - its pa_pstart is advanced by pa_len to 32768, which
lies in the next block group. If this exhausted pa (with pa_len == 0)
is still in the bb_prealloc_list during the buddy check, the assertion
incorrectly flags it as belonging to the wrong group. A possible
sequence is as follows:
ext4_mb_new_blocks
ext4_mb_release_context
pa->pa_pstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len)
pa->pa_len -= ac->ac_b_ex.fe_len
__mb_check_buddy
for each pa in group
ext4_get_group_no_and_offset
MB_CHECK_ASSERT(groupnr == e4b->bd_group)
To fix this, we modify the check to skip block group validation for
exhausted preallocations (where pa_len == 0). Such entries are in a
transitional state and will be removed from the list soon, so they
should not trigger an assertion. This change prevents the false
positive while maintaining the integrity of the checks for active
allocations.
Fixes: c9de560ded ("ext4: Add multi block allocator for ext4")
Signed-off-by: Yongjian Sun <sunyongjian1@huawei.com>
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Message-ID: <20251106060614.631382-2-sunyongjian@huaweicloud.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Pull ext4 updates from Ted Ts'o:
"New ext4 features:
- Add support so tune2fs can modify/update the superblock using an
ioctl, without needing write access to the block device
- Add support for 32-bit reserved uid's and gid's
Bug fixes:
- Fix potential warnings and other failures caused by corrupted /
fuzzed file systems
- Fail unaligned direct I/O write with EINVAL instead of silently
falling back to buffered I/O
- Correectly handle fsmap queries for metadata mappings
- Avoid journal stalls caused by writeback throttling
- Add some missing GFP_NOFAIL flags to avoid potential deadlocks
under extremem memory pressure
Cleanups:
- Remove obsolete EXT3 Kconfigs"
* tag 'ext4_for_linus-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: fix checks for orphan inodes
ext4: validate ea_ino and size in check_xattrs
ext4: guard against EA inode refcount underflow in xattr update
ext4: implemet new ioctls to set and get superblock parameters
ext4: add support for 32-bit default reserved uid and gid values
ext4: avoid potential buffer over-read in parse_apply_sb_mount_options()
ext4: fix an off-by-one issue during moving extents
ext4: increase i_disksize to offset + len in ext4_update_disksize_before_punch()
ext4: verify orphan file size is not too big
ext4: fail unaligned direct IO write with EINVAL
ext4: correctly handle queries for metadata mappings
ext4: increase IO priority of fastcommit
ext4: remove obsolete EXT3 config options
jbd2: increase IO priority of checkpoint
ext4: fix potential null deref in ext4_mb_init()
ext4: add ext4_sb_bread_nofail() helper function for ext4_free_branches()
ext4: replace min/max nesting with clamp()
fs: ext4: change GFP_KERNEL to GFP_NOFS to avoid deadlock
Currently if a user enqueue a work item using schedule_delayed_work() the
used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use
WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to
schedule_work() that is using system_wq and queue_work(), that makes use
again of WORK_CPU_UNBOUND.
This lack of consistentcy cannot be addressed without refactoring the API.
system_unbound_wq should be the default workqueue so as not to enforce
locality constraints for random work whenever it's not required.
Adding system_dfl_wq to encourage its use when unbound work should be used.
The old system_unbound_wq will be kept for a few release cycles.
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
Link: https://lore.kernel.org/20250916082906.77439-2-marco.crivellari@suse.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
Although we now perform ordered traversal within an xarray, this is
currently limited to a single xarray. However, we have multiple such
xarrays, which prevents us from guaranteeing a linear-like traversal
where all groups on the right are visited before all groups on the left.
For example, suppose we have 128 block groups, with a target group of 64,
a target length corresponding to an order of 1, and available free groups
of 16 (order 1) and group 65 (order 8):
For linear traversal, when no suitable free block is found in group 64, it
will search in the next block group until group 127, then start searching
from 0 up to block group 63. It ensures continuous forward traversal, which
is consistent with the unidirectional rotation behavior of HDD platters.
Additionally, the block group lock contention during freeing block is
unavoidable. The goal increasing from 0 to 64 indicates that previously
scanned groups (which had no suitable free space and are likely to free
blocks later) and skipped groups (which are currently in use) have newly
freed some used blocks. If we allocate blocks in these groups, the
probability of competing with other processes increases.
For non-linear traversal, we first traverse all groups in order_1. If only
group 16 has free space in this list, we first traverse [63, 128), then
traverse [0, 64) to find the available group 16, and then allocate blocks
in group 16. Therefore, it cannot guarantee continuous traversal in one
direction, thus increasing the probability of contention.
So refactor ext4_mb_scan_groups_xarray() to ext4_mb_scan_groups_xa_range()
to only traverse a fixed range of groups, and move the logic for handling
wrap around to the caller. The caller first iterates through all xarrays
in the range [start, ngroups) and then through the range [0, start). This
approach simulates a linear scan, which reduces contention between freeing
blocks and allocating blocks.
Assume we have the following groups, where "|" denotes the xarray traversal
start position:
order_1_groups: AB | CD
order_2_groups: EF | GH
Traversal order:
Before: C > D > A > B > G > H > E > F
After: C > D > G > H > A > B > E > F
Performance test data follows:
|CPU: Kunpeng 920 | P80 | P1 |
|Memory: 512GB |------------------------|-------------------------|
|960GB SSD (0.5GB/s)| base | patched | base | patched |
|-------------------|-------|----------------|--------|----------------|
|mb_optimize_scan=0 | 19555 | 20049 (+2.5%) | 315636 | 316724 (-0.3%) |
|mb_optimize_scan=1 | 15496 | 19342 (+24.8%) | 323569 | 328324 (+1.4%) |
|CPU: AMD 9654 * 2 | P96 | P1 |
|Memory: 1536GB |------------------------|-------------------------|
|960GB SSD (1GB/s) | base | patched | base | patched |
|-------------------|-------|----------------|--------|----------------|
|mb_optimize_scan=0 | 53192 | 52125 (-2.0%) | 212678 | 215136 (+1.1%) |
|mb_optimize_scan=1 | 37636 | 50331 (+33.7%) | 214189 | 209431 (-2.2%) |
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20250714130327.1830534-18-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit converts the `choose group` logic to `scan group` using
previously prepared helper functions. This allows us to leverage xarrays
for ordered non-linear traversal, thereby mitigating the "bouncing" issue
inherent in the `choose group` mechanism.
This also decouples linear and non-linear traversals, leading to cleaner
and more readable code.
Key changes:
* ext4_mb_choose_next_group() is refactored to ext4_mb_scan_groups().
* Replaced ext4_mb_good_group() with ext4_mb_scan_group() in non-linear
traversals, and related functions now return error codes instead of
group info.
* Added ext4_mb_scan_groups_linear() for performing linear scans starting
from a specific group for a set number of times.
* Linear scans now execute up to sbi->s_mb_max_linear_groups times,
so ac_groups_linear_remaining is removed as it's no longer used.
* ac->ac_criteria is now used directly instead of passing cr around.
Also, ac->ac_criteria is incremented directly after groups scan fails
for the corresponding criteria.
* Since we're now directly scanning groups instead of finding a good group
then scanning, the following variables and flags are no longer needed,
s_bal_cX_groups_considered is sufficient.
s_bal_p2_aligned_bad_suggestions
s_bal_goal_fast_bad_suggestions
s_bal_best_avail_bad_suggestions
EXT4_MB_CR_POWER2_ALIGNED_OPTIMIZED
EXT4_MB_CR_GOAL_LEN_FAST_OPTIMIZED
EXT4_MB_CR_BEST_AVAIL_LEN_OPTIMIZED
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20250714130327.1830534-17-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
While traversing the list, holding a spin_lock prevents load_buddy, making
direct use of ext4_try_lock_group impossible. This can lead to a bouncing
scenario where spin_is_locked(grp_A) succeeds, but ext4_try_lock_group()
fails, forcing the list traversal to repeatedly restart from grp_A.
In contrast, linear traversal directly uses ext4_try_lock_group(),
avoiding this bouncing. Therefore, we need a lockless, ordered traversal
to achieve linear-like efficiency.
Therefore, this commit converts both average fragment size lists and
largest free order lists into ordered xarrays.
In an xarray, the index represents the block group number and the value
holds the block group information; a non-empty value indicates the block
group's presence.
While insertion and deletion complexity remain O(1), lookup complexity
changes from O(1) to O(nlogn), which may slightly reduce single-threaded
performance.
Additionally, xarray insertions might fail, potentially due to memory
allocation issues. However, since we have linear traversal as a fallback,
this isn't a major problem. Therefore, we've only added a warning message
for insertion failures here.
A helper function ext4_mb_find_good_group_xarray() is added to find good
groups in the specified xarray starting at the specified position start,
and when it reaches ngroups-1, it wraps around to 0 and then to start-1.
This ensures an ordered traversal within the xarray.
Performance test results are as follows: Single-process operations
on an empty disk show negligible impact, while multi-process workloads
demonstrate a noticeable performance gain.
|CPU: Kunpeng 920 | P80 | P1 |
|Memory: 512GB |------------------------|-------------------------|
|960GB SSD (0.5GB/s)| base | patched | base | patched |
|-------------------|-------|----------------|--------|----------------|
|mb_optimize_scan=0 | 20097 | 19555 (-2.6%) | 316141 | 315636 (-0.2%) |
|mb_optimize_scan=1 | 13318 | 15496 (+16.3%) | 325273 | 323569 (-0.5%) |
|CPU: AMD 9654 * 2 | P96 | P1 |
|Memory: 1536GB |------------------------|-------------------------|
|960GB SSD (1GB/s) | base | patched | base | patched |
|-------------------|-------|----------------|--------|----------------|
|mb_optimize_scan=0 | 53603 | 53192 (-0.7%) | 214243 | 212678 (-0.7%) |
|mb_optimize_scan=1 | 20887 | 37636 (+80.1%) | 213632 | 214189 (+0.2%) |
[ Applied spelling fixes per discussion on the ext4-list see thread
referened in the Link tag. --tytso]
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20250714130327.1830534-16-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The grp->bb_largest_free_order is updated regardless of whether
mb_optimize_scan is enabled. This can lead to inconsistencies between
grp->bb_largest_free_order and the actual s_mb_largest_free_orders list
index when mb_optimize_scan is repeatedly enabled and disabled via remount.
For example, if mb_optimize_scan is initially enabled, largest free
order is 3, and the group is in s_mb_largest_free_orders[3]. Then,
mb_optimize_scan is disabled via remount, block allocations occur,
updating largest free order to 2. Finally, mb_optimize_scan is re-enabled
via remount, more block allocations update largest free order to 1.
At this point, the group would be removed from s_mb_largest_free_orders[3]
under the protection of s_mb_largest_free_orders_locks[2]. This lock
mismatch can lead to list corruption.
To fix this, whenever grp->bb_largest_free_order changes, we now always
attempt to remove the group from its old order list. However, we only
insert the group into the new order list if `mb_optimize_scan` is enabled.
This approach helps prevent lock inconsistencies and ensures the data in
the order lists remains reliable.
Fixes: 196e402adf ("ext4: improve cr 0 / cr 1 group scanning")
CC: stable@vger.kernel.org
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20250714130327.1830534-12-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Groups with no free blocks shouldn't be in any average fragment size list.
However, when all blocks in a group are allocated(i.e., bb_fragments or
bb_free is 0), we currently skip updating the average fragment size, which
means the group isn't removed from its previous s_mb_avg_fragment_size[old]
list.
This created "zombie" groups that were always skipped during traversal as
they couldn't satisfy any block allocation requests, negatively impacting
traversal efficiency.
Therefore, when a group becomes completely full, bb_avg_fragment_size_order
is now set to -1. If the old order was not -1, a removal operation is
performed; if the new order is not -1, an insertion is performed.
Fixes: 196e402adf ("ext4: improve cr 0 / cr 1 group scanning")
CC: stable@vger.kernel.org
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20250714130327.1830534-11-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Attempt to merge ext4_free_data with already inserted free extents prior
to adding new ones. This strategy drastically cuts down the number of
times locks are held.
For example, if prev, new, and next extents are all mergeable, the existing
code (before this patch) requires acquiring the s_md_lock three times:
prev merge into new and free prev // hold lock
next merge into new and free next // hold lock
insert new // hold lock
After the patch, it only needs to be acquired once:
new merge into next and free new // no lock
next merge into prev and free next // hold lock
Performance test data follows:
Test: Running will-it-scale/fallocate2 on CPU-bound containers.
Observation: Average fallocate operations per container per second.
|CPU: Kunpeng 920 | P80 | P1 |
|Memory: 512GB |------------------------|-------------------------|
|960GB SSD (0.5GB/s)| base | patched | base | patched |
|-------------------|-------|----------------|--------|----------------|
|mb_optimize_scan=0 | 20043 | 20097 (+0.2%) | 314331 | 316141 (+0.5%) |
|mb_optimize_scan=1 | 7290 | 13318 (+87.4%) | 324226 | 325273 (+0.3%) |
|CPU: AMD 9654 * 2 | P96 | P1 |
|Memory: 1536GB |------------------------|-------------------------|
|960GB SSD (1GB/s) | base | patched | base | patched |
|-------------------|-------|----------------|--------|----------------|
|mb_optimize_scan=0 | 54999 | 53603 (-2.5%) | 214380 | 214243 (-0.06%)|
|mb_optimize_scan=1 | 13497 | 20887 (+54.6%) | 216276 | 213632 (-1.2%) |
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20250714130327.1830534-10-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Previously, s_md_lock was used to protect s_mb_free_pending during
modifications, while smp_mb() ensured fresh reads, so s_md_lock just
guarantees the atomicity of s_mb_free_pending. Thus we optimized it by
converting s_mb_free_pending into an atomic variable, thereby eliminating
s_md_lock and minimizing lock contention. This also prepares for future
lockless merging of free extents.
Following this modification, s_md_lock is exclusively responsible for
managing insertions and deletions within s_freed_data_list, along with
operations involving list_splice.
Performance test data follows:
Test: Running will-it-scale/fallocate2 on CPU-bound containers.
Observation: Average fallocate operations per container per second.
|CPU: Kunpeng 920 | P80 | P1 |
|Memory: 512GB |------------------------|-------------------------|
|960GB SSD (0.5GB/s)| base | patched | base | patched |
|-------------------|-------|----------------|--------|----------------|
|mb_optimize_scan=0 | 19628 | 20043 (+2.1%) | 320885 | 314331 (-2.0%) |
|mb_optimize_scan=1 | 7129 | 7290 (+2.2%) | 321275 | 324226 (+0.9%) |
|CPU: AMD 9654 * 2 | P96 | P1 |
|Memory: 1536GB |------------------------|-------------------------|
|960GB SSD (1GB/s) | base | patched | base | patched |
|-------------------|-------|----------------|--------|----------------|
|mb_optimize_scan=0 | 53760 | 54999 (+2.3%) | 213145 | 214380 (+0.5%) |
|mb_optimize_scan=1 | 12716 | 13497 (+6.1%) | 215262 | 216276 (+0.4%) |
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20250714130327.1830534-9-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
When allocating data blocks, if the first try (goal allocation) fails and
stream allocation is on, it tries a global goal starting from the last
group we used (s_mb_last_group). This helps cluster large files together
to reduce free space fragmentation, and the data block contiguity also
accelerates write-back to disk.
However, when multiple processes allocate blocks, having just one global
goal means they all fight over the same group. This drastically lowers
the chances of extents merging and leads to much worse file fragmentation.
To mitigate this multi-process contention, we now employ multiple global
goals, with the number of goals being the minimum between the number of
possible CPUs and one-quarter of the filesystem's total block group count.
To ensure a consistent goal for each inode, we select the corresponding
goal by taking the inode number modulo the total number of goals.
Performance test data follows:
Test: Running will-it-scale/fallocate2 on CPU-bound containers.
Observation: Average fallocate operations per container per second.
|CPU: Kunpeng 920 | P80 | P1 |
|Memory: 512GB |------------------------|-------------------------|
|960GB SSD (0.5GB/s)| base | patched | base | patched |
|-------------------|-------|----------------|--------|----------------|
|mb_optimize_scan=0 | 9636 | 19628 (+103%) | 337597 | 320885 (-4.9%) |
|mb_optimize_scan=1 | 4834 | 7129 (+47.4%) | 341440 | 321275 (-5.9%) |
|CPU: AMD 9654 * 2 | P96 | P1 |
|Memory: 1536GB |------------------------|-------------------------|
|960GB SSD (1GB/s) | base | patched | base | patched |
|-------------------|-------|----------------|--------|----------------|
|mb_optimize_scan=0 | 22341 | 53760 (+140%) | 219707 | 213145 (-2.9%) |
|mb_optimize_scan=1 | 9177 | 12716 (+38.5%) | 215732 | 215262 (+0.2%) |
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20250714130327.1830534-6-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
After we optimized the block group lock, we found another lock
contention issue when running will-it-scale/fallocate2 with multiple
processes. The fallocate's block allocation and the truncate's block
release were fighting over the s_md_lock. The problem is, this lock
protects totally different things in those two processes: the list of
freed data blocks (s_freed_data_list) when releasing, and where to start
looking for new blocks (mb_last_group) when allocating.
Now we only need to track s_mb_last_group and no longer need to track
s_mb_last_start, so we don't need the s_md_lock lock to ensure that the
two are consistent. Since s_mb_last_group is merely a hint and doesn't
require strong synchronization, READ_ONCE/WRITE_ONCE is sufficient.
Besides, the s_mb_last_group data type only requires ext4_group_t
(i.e., unsigned int), rendering unsigned long superfluous.
Performance test data follows:
Test: Running will-it-scale/fallocate2 on CPU-bound containers.
Observation: Average fallocate operations per container per second.
|CPU: Kunpeng 920 | P80 | P1 |
|Memory: 512GB |------------------------|-------------------------|
|960GB SSD (0.5GB/s)| base | patched | base | patched |
|-------------------|-------|----------------|--------|----------------|
|mb_optimize_scan=0 | 4821 | 9636 (+99.8%) | 314065 | 337597 (+7.4%) |
|mb_optimize_scan=1 | 4784 | 4834 (+1.04%) | 316344 | 341440 (+7.9%) |
|CPU: AMD 9654 * 2 | P96 | P1 |
|Memory: 1536GB |------------------------|-------------------------|
|960GB SSD (1GB/s) | base | patched | base | patched |
|-------------------|-------|----------------|--------|----------------|
|mb_optimize_scan=0 | 15371 | 22341 (+45.3%) | 205851 | 219707 (+6.7%) |
|mb_optimize_scan=1 | 6101 | 9177 (+50.4%) | 207373 | 215732 (+4.0%) |
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20250714130327.1830534-5-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
When ext4 allocates blocks, we used to just go through the block groups
one by one to find a good one. But when there are tons of block groups
(like hundreds of thousands or even millions) and not many have free space
(meaning they're mostly full), it takes a really long time to check them
all, and performance gets bad. So, we added the "mb_optimize_scan" mount
option (which is on by default now). It keeps track of some group lists,
so when we need a free block, we can just grab a likely group from the
right list. This saves time and makes block allocation much faster.
But when multiple processes or containers are doing similar things, like
constantly allocating 8k blocks, they all try to use the same block group
in the same list. Even just two processes doing this can cut the IOPS in
half. For example, one container might do 300,000 IOPS, but if you run two
at the same time, the total is only 150,000.
Since we can already look at block groups in a non-linear way, the first
and last groups in the same list are basically the same for finding a block
right now. Therefore, add an ext4_try_lock_group() helper function to skip
the current group when it is locked by another process, thereby avoiding
contention with other processes. This helps ext4 make better use of having
multiple block groups.
Also, to make sure we don't skip all the groups that have free space
when allocating blocks, we won't try to skip busy groups anymore when
ac_criteria is CR_ANY_FREE.
Performance test data follows:
Test: Running will-it-scale/fallocate2 on CPU-bound containers.
Observation: Average fallocate operations per container per second.
|CPU: Kunpeng 920 | P80 |
|Memory: 512GB |-------------------------|
|960GB SSD (0.5GB/s)| base | patched |
|-------------------|-------|-----------------|
|mb_optimize_scan=0 | 2667 | 4821 (+80.7%) |
|mb_optimize_scan=1 | 2643 | 4784 (+81.0%) |
|CPU: AMD 9654 * 2 | P96 |
|Memory: 1536GB |-------------------------|
|960GB SSD (1GB/s) | base | patched |
|-------------------|-------|-----------------|
|mb_optimize_scan=0 | 3450 | 15371 (+345%) |
|mb_optimize_scan=1 | 3209 | 6101 (+90.0%) |
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20250714130327.1830534-2-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
-Wflex-array-member-not-at-end was introduced in GCC-14, and we are
getting ready to enable it, globally.
Use the `DEFINE_RAW_FLEX()` helper for an on-stack definition of
a flexible structure where the size of the flexible-array member
is known at compile-time, and refactor the rest of the code,
accordingly.
So, with these changes, fix the following warning:
fs/ext4/mballoc.c:3041:40: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/Z-SF97N3AxcIMlSi@kspp
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Commit 196e402adf ("ext4: improve cr 0 / cr 1 group scanning") introduces
the sysfs control interface "mb_max_linear_groups" to address the problem
that rotational devices performance degrades when the "mb_optimize_scan"
feature is enabled, which may result in distant block group allocation.
However, the name of the interface was incorrect in the comment to the
ext4/mballoc.c file, and this patch fixes it, without further changes.
Signed-off-by: Zizhi Wo <wozizhi@huawei.com>
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20250224012005.689549-1-wozizhi@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Since both SHUTDOWN and EMERGENCY_RO are emergency states of the ext4 file
system, and they are checked in similar locations, we have added a helper
function, ext4_emergency_state(), to determine whether the current file
system is in one of these two emergency states.
Then, replace calls to ext4_forced_shutdown() with ext4_emergency_state()
in those functions that could potentially trigger write operations.
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20250122114130.229709-4-libaokun@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The original implementation ext4's FS_IOC_GETFSMAP handling only
worked when the range of queried blocks included at least one free
(unallocated) block range. This is because how the metadata blocks
were emitted was as a side effect of ext4_mballoc_query_range()
calling ext4_getfsmap_datadev_helper(), and that function was only
called when a free block range was identified. As a result, this
caused generic/365 to fail.
Fix this by creating a new function ext4_getfsmap_meta_helper() which
gets called so that blocks before the first free block range in a
block group can get properly reported.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
Although we have checks to make sure s_stripe is a multiple of cluster
size, in case we accidentally end up with a scenario where this is not
the case, use EXT4_NUM_B2C() so that we don't end up with unexpected
cases where EXT4_B2C(stripe) becomes 0.
Also make the is_stripe_aligned check in regular_allocator a bit more
robust while we are at it. This should ideally have no functional change
unless we have a bug somewhere causing (stripe % cluster_size != 0)
Reviewed-by: Kemeng Shi <shikemeng@huaweicloud.com>
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://patch.msgid.link/e0c0a3b58a40935a1361f668851d041575861411.1725002410.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Commit 3d56b8d2c7 ("ext4: Speed up FITRIM by recording flags in
ext4_group_info") speed up fstrim by skipping trim trimmed group. We
also has the chance to clear trimmed once there exists some block free
for this group(mount without discard), and the next trim for this group
will work well too.
For mount with discard, we will issue dicard when we free blocks, so
leave trimmed flag keep alive to skip useless trim trigger from
userspace seems reasonable. But for some case like ext4 build on
dm-thinpool(ext4 blocksize 4K, pool blocksize 128K), discard from ext4
maybe unaligned for dm thinpool, and thinpool will just finish this
discard(see process_discard_bio when begein equals to end) without
actually process discard. For this case, trim from userspace can really
help us to free some thinpool block.
So convert to clear trimmed flag for all case no matter mounted with
discard or not.
Fixes: 3d56b8d2c7 ("ext4: Speed up FITRIM by recording flags in ext4_group_info")
Signed-off-by: yangerkun <yangerkun@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20240817085510.2084444-1-yangerkun@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
