One of the paths quota writeback is called from is: freeze_super() sync_filesystem() ext4_sync_fs() dquot_writeback_dquots() Since we currently don't always flush the quota_release_work queue in this path, we can end up with the following race: 1. dquot are added to releasing_dquots list during regular operations. 2. FS freeze starts, however, this does not flush the quota_release_work queue. 3. Freeze completes. 4. Kernel eventually tries to flush the workqueue while FS is frozen which hits a WARN_ON since transaction gets started during frozen state: ext4_journal_check_start+0x28/0x110 [ext4] (unreliable) __ext4_journal_start_sb+0x64/0x1c0 [ext4] ext4_release_dquot+0x90/0x1d0 [ext4] quota_release_workfn+0x43c/0x4d0 Which is the following line: WARN_ON(sb->s_writers.frozen == SB_FREEZE_COMPLETE); Which ultimately results in generic/390 failing due to dmesg noise. This was detected on powerpc machine 15 cores. To avoid this, make sure to flush the workqueue during dquot_writeback_dquots() so we dont have any pending workitems after freeze. Reported-by: Disha Goel <disgoel@xxxxxxxxxxxxx> Signed-off-by: Ojaswin Mujoo <ojaswin@xxxxxxxxxxxxx> --- fs/quota/dquot.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c index 3dd8d6f27725..2782cfc8c302 100644 --- a/fs/quota/dquot.c +++ b/fs/quota/dquot.c @@ -729,6 +729,8 @@ int dquot_writeback_dquots(struct super_block *sb, int type) sb->dq_op->write_info(sb, cnt); dqstats_inc(DQST_SYNCS); + flush_delayed_work("a_release_work); + return ret; } EXPORT_SYMBOL(dquot_writeback_dquots); -- 2.43.5