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fs: quota: create dedicated workqueue for quota_release_work

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[ Upstream commit 72b7ceca857f38a8ca7c5629feffc63769638974 ]

There is a kernel panic due to WARN_ONCE when panic_on_warn is set.

This issue occurs when writeback is triggered due to sync call for an
opened file(ie, writeback reason is WB_REASON_SYNC). When f2fs balance
is needed at sync path, flush for quota_release_work is triggered.
By default quota_release_work is queued to "events_unbound" queue which
does not have WQ_MEM_RECLAIM flag. During f2fs balance "writeback"
workqueue tries to flush quota_release_work causing kernel panic due to
MEM_RECLAIM flag mismatch errors.

This patch creates dedicated workqueue with WQ_MEM_RECLAIM flag
for work quota_release_work.

------------[ cut here ]------------
WARNING: CPU: 4 PID: 14867 at kernel/workqueue.c:3721 check_flush_dependency+0x13c/0x148
Call trace:
 check_flush_dependency+0x13c/0x148
 __flush_work+0xd0/0x398
 flush_delayed_work+0x44/0x5c
 dquot_writeback_dquots+0x54/0x318
 f2fs_do_quota_sync+0xb8/0x1a8
 f2fs_write_checkpoint+0x3cc/0x99c
 f2fs_gc+0x190/0x750
 f2fs_balance_fs+0x110/0x168
 f2fs_write_single_data_page+0x474/0x7dc
 f2fs_write_data_pages+0x7d0/0xd0c
 do_writepages+0xe0/0x2f4
 __writeback_single_inode+0x44/0x4ac
 writeback_sb_inodes+0x30c/0x538
 wb_writeback+0xf4/0x440
 wb_workfn+0x128/0x5d4
 process_scheduled_works+0x1c4/0x45c
 worker_thread+0x32c/0x3e8
 kthread+0x11c/0x1b0
 ret_from_fork+0x10/0x20
Kernel panic - not syncing: kernel: panic_on_warn set ...

Fixes: ac6f420291b3 ("quota: flush quota_release_work upon quota writeback")
CC: stable@vger.kernel.org
Signed-off-by: Shashank A P <shashank.ap@samsung.com>
Link: https://patch.msgid.link/20250901092905.2115-1-shashank.ap@samsung.com
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Shashank A P
2025-10-20 12:16:05 -04:00
committed by Greg Kroah-Hartman
parent d7d942c9a1
commit f846eacde2
1 changed files with 9 additions and 1 deletions
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10
fs/quota/dquot.c
View File

@@ -163,6 +163,9 @@ static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES;
/* SLAB cache for dquot structures */
static struct kmem_cache *dquot_cachep;
/* workqueue for work quota_release_work*/
static struct workqueue_struct *quota_unbound_wq;
void register_quota_format(struct quota_format_type *fmt)
{
spin_lock(&dq_list_lock);
@@ -891,7 +894,7 @@ void dqput(struct dquot *dquot)
put_releasing_dquots(dquot);
atomic_dec(&dquot->dq_count);
spin_unlock(&dq_list_lock);
queue_delayed_work(system_unbound_wq, &quota_release_work, 1);
queue_delayed_work(quota_unbound_wq, &quota_release_work, 1);
}
EXPORT_SYMBOL(dqput);
@@ -3046,6 +3049,11 @@ static int __init dquot_init(void)
if (register_shrinker(&dqcache_shrinker, "dquota-cache"))
panic("Cannot register dquot shrinker");
quota_unbound_wq = alloc_workqueue("quota_events_unbound",
WQ_UNBOUND | WQ_MEM_RECLAIM, WQ_MAX_ACTIVE);
if (!quota_unbound_wq)
panic("Cannot create quota_unbound_wq\n");
return 0;
}
fs_initcall(dquot_init);