blob: 61884300bec862bece4d86c9e0ad497af16a1074 [file] [log] [blame]
From e3d91b495953a3280bf40c8cc5e154d4da7bdc69 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@mit.edu>
Date: Sun, 23 Feb 2020 14:54:58 -0500
Subject: [PATCH] dm thin metadata: fix lockdep complaint
commit 3918e0667bbac99400b44fa5aef3f8be2eeada4a upstream.
[ 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: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index 8bb723f1a569..4cd8868f8004 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;
--
2.7.4