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dm cache: Fix ABBA deadlock between shrink_slab and dm_cache_metadata_abort

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commit 352b837a5541690d4f843819028cf2b8be83d424 upstream.

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: 028ae9f76f ("dm cache: add fail io mode and needs_check flag")
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mike Snitzer 2022-11-30 13:26:32 -05:00 committed by Greg Kroah-Hartman
parent 52ba5b87a3
commit f472bfc95d
1 changed files with 47 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

52
drivers/md/dm-cache-metadata.c
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@ -551,10 +551,12 @@ static int __create_persistent_data_objects(struct dm_cache_metadata *cmd,
return r; return r;
} }
static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd) static void __destroy_persistent_data_objects(struct dm_cache_metadata *cmd,
bool destroy_bm)
{ {
dm_sm_destroy(cmd->metadata_sm); dm_sm_destroy(cmd->metadata_sm);
dm_tm_destroy(cmd->tm); dm_tm_destroy(cmd->tm);
if (destroy_bm)
dm_block_manager_destroy(cmd->bm); dm_block_manager_destroy(cmd->bm);
} }
@ -826,7 +828,7 @@ static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev,
cmd2 = lookup(bdev); cmd2 = lookup(bdev);
if (cmd2) { if (cmd2) {
mutex_unlock(&table_lock); mutex_unlock(&table_lock);
__destroy_persistent_data_objects(cmd); __destroy_persistent_data_objects(cmd, true);
kfree(cmd); kfree(cmd);
return cmd2; return cmd2;
} }
@ -874,7 +876,7 @@ void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
mutex_unlock(&table_lock); mutex_unlock(&table_lock);
if (!cmd->fail_io) if (!cmd->fail_io)
__destroy_persistent_data_objects(cmd); __destroy_persistent_data_objects(cmd, true);
kfree(cmd); kfree(cmd);
} }
} }
@ -1808,14 +1810,52 @@ int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result)
int dm_cache_metadata_abort(struct dm_cache_metadata *cmd) int dm_cache_metadata_abort(struct dm_cache_metadata *cmd)
{ {
int r; int r = -EINVAL;
struct dm_block_manager *old_bm = NULL, *new_bm = NULL;
/* fail_io is double-checked with cmd->root_lock held below */
if (unlikely(cmd->fail_io))
return r;
/*
* Replacement block manager (new_bm) is created and old_bm destroyed outside of
* cmd root_lock to avoid ABBA deadlock that would result (due to life-cycle of
* shrinker associated with the block manager's bufio client vs cmd root_lock).
* - must take shrinker_rwsem without holding cmd->root_lock
*/
new_bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
CACHE_MAX_CONCURRENT_LOCKS);
WRITE_LOCK(cmd); WRITE_LOCK(cmd);
__destroy_persistent_data_objects(cmd); if (cmd->fail_io) {
r = __create_persistent_data_objects(cmd, false); WRITE_UNLOCK(cmd);
goto out;
}
__destroy_persistent_data_objects(cmd, false);
old_bm = cmd->bm;
if (IS_ERR(new_bm)) {
DMERR("could not create block manager during abort");
cmd->bm = NULL;
r = PTR_ERR(new_bm);
goto out_unlock;
}
cmd->bm = new_bm;
r = __open_or_format_metadata(cmd, false);
if (r) {
cmd->bm = NULL;
goto out_unlock;
}
new_bm = NULL;
out_unlock:
if (r) if (r)
cmd->fail_io = true; cmd->fail_io = true;
WRITE_UNLOCK(cmd); WRITE_UNLOCK(cmd);
dm_block_manager_destroy(old_bm);
out:
if (new_bm && !IS_ERR(new_bm))
dm_block_manager_destroy(new_bm);
return r; return r;
} }