md/raid5: add rcu protection to rdev accesses in want_replace
Being in the middle of resync is no longer protection against failed
rdevs disappearing. So add rcu protection.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index e56c7e0..198b2a9 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -3239,15 +3239,16 @@
{
struct md_rdev *rdev;
int rv = 0;
- /* Doing recovery so rcu locking not required */
- rdev = sh->raid_conf->disks[disk_idx].replacement;
+
+ rcu_read_lock();
+ rdev = rcu_dereference(sh->raid_conf->disks[disk_idx].replacement);
if (rdev
&& !test_bit(Faulty, &rdev->flags)
&& !test_bit(In_sync, &rdev->flags)
&& (rdev->recovery_offset <= sh->sector
|| rdev->mddev->recovery_cp <= sh->sector))
rv = 1;
-
+ rcu_read_unlock();
return rv;
}