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| author | Ojaswin Mujoo <ojaswin@linux.ibm.com> | 2024-11-21 18:08:54 +0530 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-12-09 10:40:55 +0100 |
| commit | 8ea87e34792258825d290f4dc5216276e91cb224 (patch) | |
| tree | d41adc709968a4f210a6308204fed8ec7f2a76c8 /fs/quota | |
| parent | 2e87ea9bf3671abdedeb06d02e51509528b1ce94 (diff) | |
| download | linux-8ea87e34792258825d290f4dc5216276e91cb224.tar.gz linux-8ea87e34792258825d290f4dc5216276e91cb224.tar.bz2 linux-8ea87e34792258825d290f4dc5216276e91cb224.zip | |
quota: flush quota_release_work upon quota writeback
[ Upstream commit ac6f420291b3fee1113f21d612fa88b628afab5b ]
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@linux.ibm.com>
CC: stable@vger.kernel.org
Fixes: dabc8b207566 ("quota: fix dqput() to follow the guarantees dquot_srcu should provide")
Reviewed-by: Baokun Li <libaokun1@huawei.com>
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20241121123855.645335-2-ojaswin@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs/quota')
| -rw-r--r-- | fs/quota/dquot.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c index b40410cd39af..71c0ce31a4c4 100644 --- a/fs/quota/dquot.c +++ b/fs/quota/dquot.c @@ -689,6 +689,8 @@ int dquot_writeback_dquots(struct super_block *sb, int type) WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount)); + flush_delayed_work("a_release_work); + for (cnt = 0; cnt < MAXQUOTAS; cnt++) { if (type != -1 && cnt != type) continue; |