From: Mike Snitzer snitzer@kernel.org
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: 028ae9f76f29 ("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 --- drivers/md/dm-cache-metadata.c | 54 +++++++++++++++++++++++++++++++++++------ 1 file changed, 47 insertions(+), 7 deletions(-)
--- a/drivers/md/dm-cache-metadata.c +++ b/drivers/md/dm-cache-metadata.c @@ -551,11 +551,13 @@ static int __create_persistent_data_obje 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_tm_destroy(cmd->tm); - dm_block_manager_destroy(cmd->bm); + if (destroy_bm) + dm_block_manager_destroy(cmd->bm); }
typedef unsigned long (*flags_mutator)(unsigned long); @@ -826,7 +828,7 @@ static struct dm_cache_metadata *lookup_ cmd2 = lookup(bdev); if (cmd2) { mutex_unlock(&table_lock); - __destroy_persistent_data_objects(cmd); + __destroy_persistent_data_objects(cmd, true); kfree(cmd); return cmd2; } @@ -874,7 +876,7 @@ void dm_cache_metadata_close(struct dm_c mutex_unlock(&table_lock);
if (!cmd->fail_io) - __destroy_persistent_data_objects(cmd); + __destroy_persistent_data_objects(cmd, true); kfree(cmd); } } @@ -1808,14 +1810,52 @@ int dm_cache_metadata_needs_check(struct
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); - __destroy_persistent_data_objects(cmd); - r = __create_persistent_data_objects(cmd, false); + if (cmd->fail_io) { + 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) cmd->fail_io = true; 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; }