| From 11d7d4f82ae94263e7209414ae06bb248cd0f732 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Sun, 23 Feb 2020 14:54:58 -0500 |
| Subject: dm thin metadata: fix lockdep complaint |
| |
| From: Theodore Ts'o <tytso@mit.edu> |
| |
| [ Upstream commit 3918e0667bbac99400b44fa5aef3f8be2eeada4a ] |
| |
| [ 3934.173244] ====================================================== |
| [ 3934.179572] WARNING: possible circular locking dependency detected |
| [ 3934.185884] 5.4.21-xfstests #1 Not tainted |
| [ 3934.190151] ------------------------------------------------------ |
| [ 3934.196673] dmsetup/8897 is trying to acquire lock: |
| [ 3934.201688] ffffffffbce82b18 (shrinker_rwsem){++++}, at: unregister_shrinker+0x22/0x80 |
| [ 3934.210268] |
| but task is already holding lock: |
| [ 3934.216489] ffff92a10cc5e1d0 (&pmd->root_lock){++++}, at: dm_pool_metadata_close+0xba/0x120 |
| [ 3934.225083] |
| which lock already depends on the new lock. |
| |
| [ 3934.564165] Chain exists of: |
| shrinker_rwsem --> &journal->j_checkpoint_mutex --> &pmd->root_lock |
| |
| For a more detailed lockdep report, please see: |
| |
| https://lore.kernel.org/r/20200220234519.GA620489@mit.edu |
| |
| We shouldn't need to hold the lock while are just tearing down and |
| freeing the whole metadata pool structure. |
| |
| Fixes: 44d8ebf436399a4 ("dm thin metadata: use pool locking at end of dm_pool_metadata_close") |
| Signed-off-by: Theodore Ts'o <tytso@mit.edu> |
| Signed-off-by: Mike Snitzer <snitzer@redhat.com> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/md/dm-thin-metadata.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c |
| index 8bb723f1a569a..4cd8868f80040 100644 |
| --- a/drivers/md/dm-thin-metadata.c |
| +++ b/drivers/md/dm-thin-metadata.c |
| @@ -960,9 +960,9 @@ int dm_pool_metadata_close(struct dm_pool_metadata *pmd) |
| DMWARN("%s: __commit_transaction() failed, error = %d", |
| __func__, r); |
| } |
| + pmd_write_unlock(pmd); |
| if (!pmd->fail_io) |
| __destroy_persistent_data_objects(pmd); |
| - pmd_write_unlock(pmd); |
| |
| kfree(pmd); |
| return 0; |
| -- |
| 2.20.1 |
| |