Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
dm cache: Fix ABBA deadlock between shrink_slab and dm_cache_metadata_abort
Same ABBA deadlock pattern fixed in commit 4b60f452ec51 ("dm thin: Fix
ABBA deadlock between shrink_slab and dm_pool_abort_metadata") to
DM-cache's metadata.
Reported-by: Zhihao Cheng <chengzhihao1@huawei.com>
Cc: stable@vger.kernel.org
Fixes: 028ae9f76f29 ("dm cache: add fail io mode and needs_check flag")
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
+47
-7
+47
-7
drivers/md/dm-cache-metadata.c
+47
-7
drivers/md/dm-cache-metadata.c
···
551
551
return r;
552
552
}
553
553
554
-
static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd)
554
+
static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd,
555
+
bool destroy_bm)
555
556
{
556
557
dm_sm_destroy(cmd->metadata_sm);
557
558
dm_tm_destroy(cmd->tm);
558
-
dm_block_manager_destroy(cmd->bm);
559
+
if (destroy_bm)
560
+
dm_block_manager_destroy(cmd->bm);
559
561
}
560
562
561
563
typedef unsigned long (*flags_mutator)(unsigned long);
···
828
826
cmd2 = lookup(bdev);
829
827
if (cmd2) {
830
828
mutex_unlock(&table_lock);
831
-
__destroy_persistent_data_objects(cmd);
829
+
__destroy_persistent_data_objects(cmd, true);
832
830
kfree(cmd);
833
831
return cmd2;
834
832
}
···
876
874
mutex_unlock(&table_lock);
877
875
878
876
if (!cmd->fail_io)
879
-
__destroy_persistent_data_objects(cmd);
877
+
__destroy_persistent_data_objects(cmd, true);
880
878
kfree(cmd);
881
879
}
882
880
}
···
1809
1807
1810
1808
int dm_cache_metadata_abort(struct dm_cache_metadata *cmd)
1811
1809
{
1812
-
int r;
1810
+
int r = -EINVAL;
1811
+
struct dm_block_manager *old_bm = NULL, *new_bm = NULL;
1812
+
1813
+
/* fail_io is double-checked with cmd->root_lock held below */
1814
+
if (unlikely(cmd->fail_io))
1815
+
return r;
1816
+
1817
+
/*
1818
+
* Replacement block manager (new_bm) is created and old_bm destroyed outside of
1819
+
* cmd root_lock to avoid ABBA deadlock that would result (due to life-cycle of
1820
+
* shrinker associated with the block manager's bufio client vs cmd root_lock).
1821
+
* - must take shrinker_rwsem without holding cmd->root_lock
1822
+
*/
1823
+
new_bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
1824
+
CACHE_MAX_CONCURRENT_LOCKS);
1813
1825
1814
1826
WRITE_LOCK(cmd);
1815
-
__destroy_persistent_data_objects(cmd);
1816
-
r = __create_persistent_data_objects(cmd, false);
1827
+
if (cmd->fail_io) {
1828
+
WRITE_UNLOCK(cmd);
1829
+
goto out;
1830
+
}
1831
+
1832
+
__destroy_persistent_data_objects(cmd, false);
1833
+
old_bm = cmd->bm;
1834
+
if (IS_ERR(new_bm)) {
1835
+
DMERR("could not create block manager during abort");
1836
+
cmd->bm = NULL;
1837
+
r = PTR_ERR(new_bm);
1838
+
goto out_unlock;
1839
+
}
1840
+
1841
+
cmd->bm = new_bm;
1842
+
r = __open_or_format_metadata(cmd, false);
1843
+
if (r) {
1844
+
cmd->bm = NULL;
1845
+
goto out_unlock;
1846
+
}
1847
+
new_bm = NULL;
1848
+
out_unlock:
1817
1849
if (r)
1818
1850
cmd->fail_io = true;
1819
1851
WRITE_UNLOCK(cmd);
1852
+
dm_block_manager_destroy(old_bm);
1853
+
out:
1854
+
if (new_bm && !IS_ERR(new_bm))
1855
+
dm_block_manager_destroy(new_bm);
1820
1856
1821
1857
return r;
1822
1858
}