From 4a9631ffe5205583800d8bdf9735381f0a09324d Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Fri, 5 May 2017 14:40:13 -0400 Subject: [PATCH 1/1] dm cache metadata: fail operations if fail_io mode has been established commit 10add84e276432d9dd8044679a1028dd4084117e upstream. Otherwise it is possible to trigger crashes due to the metadata being inaccessible yet these methods don't safely account for that possibility without these checks. Reported-by: Mikulas Patocka Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-cache-metadata.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c index 3970cda10080..d3c55d7754af 100644 --- a/drivers/md/dm-cache-metadata.c +++ b/drivers/md/dm-cache-metadata.c @@ -1326,17 +1326,19 @@ void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd, int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown) { - int r; + int r = -EINVAL; flags_mutator mutator = (clean_shutdown ? set_clean_shutdown : clear_clean_shutdown); WRITE_LOCK(cmd); + if (cmd->fail_io) + goto out; + r = __commit_transaction(cmd, mutator); if (r) goto out; r = __begin_transaction(cmd); - out: WRITE_UNLOCK(cmd); return r; @@ -1348,7 +1350,8 @@ int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd, int r = -EINVAL; READ_LOCK(cmd); - r = dm_sm_get_nr_free(cmd->metadata_sm, result); + if (!cmd->fail_io) + r = dm_sm_get_nr_free(cmd->metadata_sm, result); READ_UNLOCK(cmd); return r; @@ -1360,7 +1363,8 @@ int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd, int r = -EINVAL; READ_LOCK(cmd); - r = dm_sm_get_nr_blocks(cmd->metadata_sm, result); + if (!cmd->fail_io) + r = dm_sm_get_nr_blocks(cmd->metadata_sm, result); READ_UNLOCK(cmd); return r; -- 2.11.0