From: Brian Foster <bfoster@redhat.com> mainline inclusion from mainline-v7.0-rc1 commit 94a8cea54cd935c54fa2fba70354757c0fc245e3 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/13898 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- 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: 0087d9fb3f29 ("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 Conflicts: fs/ext4/mballoc-test.c fs/ext4/mballoc.c [mainline 2f94711b098b & 7c9fa399a369 not applied] Signed-off-by: Yongjian Sun <sunyongjian1@huawei.com> --- fs/ext4/mballoc.c | 21 +++++---------------- 1 file changed, 5 insertions(+), 16 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index ba5a8f2c7bff..81c3ba818aca 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -4071,8 +4071,7 @@ void ext4_exit_mballoc(void) * Returns 0 if success or error code */ static noinline_for_stack int -ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac, - handle_t *handle, unsigned int reserv_clstrs) +ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac, handle_t *handle) { struct buffer_head *bitmap_bh = NULL; struct ext4_group_desc *gdp; @@ -4158,13 +4157,6 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac, ext4_unlock_group(sb, ac->ac_b_ex.fe_group); percpu_counter_sub(&sbi->s_freeclusters_counter, ac->ac_b_ex.fe_len); - /* - * Now reduce the dirty block count also. Should not go negative - */ - if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED)) - /* release all the reserved blocks if non delalloc */ - percpu_counter_sub(&sbi->s_dirtyclusters_counter, - reserv_clstrs); if (sbi->s_log_groups_per_flex) { ext4_group_t flex_group = ext4_flex_group(sbi, @@ -6402,7 +6394,7 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle, ext4_mb_pa_put_free(ac); } if (likely(ac->ac_status == AC_STATUS_FOUND)) { - *errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_clstrs); + *errp = ext4_mb_mark_diskspace_used(ac, handle); if (*errp) { ext4_discard_allocated_blocks(ac); goto errout; @@ -6433,12 +6425,9 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle, out: if (inquota && ar->len < inquota) dquot_free_block(ar->inode, EXT4_C2B(sbi, inquota - ar->len)); - if (!ar->len) { - if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0) - /* release all the reserved blocks if non delalloc */ - percpu_counter_sub(&sbi->s_dirtyclusters_counter, - reserv_clstrs); - } + /* release any reserved blocks */ + if (reserv_clstrs) + percpu_counter_sub(&sbi->s_dirtyclusters_counter, reserv_clstrs); trace_ext4_allocate_blocks(ar, (unsigned long long)block); -- 2.39.2