dm thin metadata: fix a race when entering fail mode
In dm_thin_find_block() the ->fail_io flag was checked outside the
metadata device's root_lock, causing dm_thin_find_block() to race with
the setting of this flag.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index 8b521e3..48dfe3c 100644
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -1390,10 +1390,11 @@
dm_block_t keys[2] = { td->id, block };
struct dm_btree_info *info;
- if (pmd->fail_io)
- return -EINVAL;
-
down_read(&pmd->root_lock);
+ if (pmd->fail_io) {
+ up_read(&pmd->root_lock);
+ return -EINVAL;
+ }
if (can_issue_io) {
info = &pmd->info;