dm cache metadata: fail operations if fail_io mode has been established
authorMike Snitzer <snitzer@redhat.com>
Fri, 5 May 2017 18:40:13 +0000 (14:40 -0400)
committerMike Snitzer <snitzer@redhat.com>
Fri, 5 May 2017 18:40:13 +0000 (14:40 -0400)
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.

Cc: stable@vger.kernel.org
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
drivers/md/dm-cache-metadata.c

index 8568dbd50ba402f23e0d5870e6c7d07737e530be..4a4e9c75fc4cddca59c30df2f18ebaa6f0baaa61 100644 (file)
@@ -1624,17 +1624,19 @@ 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;
@@ -1646,7 +1648,8 @@ 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;
@@ -1658,7 +1661,8 @@ 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;