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 <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c
index 6955778..6937ca4 100644
--- a/drivers/md/dm-cache-metadata.c
+++ b/drivers/md/dm-cache-metadata.c
@@ -1383,17 +1383,19 @@
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;
@@ -1405,7 +1407,8 @@
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;
@@ -1417,7 +1420,8 @@
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;