md/raid5: activate raid6 rmw feature

[deliverable/linux.git] / drivers / md / dm-raid1.c

diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index 7dfdb5c746d6f31960902350c33b7457485caadb..089d62751f7ff2a3aedf7e441cb88bec0d06b8a7 100644 (file)
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -604,6 +604,15 @@ static void write_callback(unsigned long error, void *context)
                return;
        }
 
+       /*
+        * If the bio is discard, return an error, but do not
+        * degrade the array.
+        */
+       if (bio->bi_rw & REQ_DISCARD) {
+               bio_endio(bio, -EOPNOTSUPP);
+               return;
+       }
+
        for (i = 0; i < ms->nr_mirrors; i++)
                if (test_bit(i, &error))
                        fail_mirror(ms->mirror + i, DM_RAID1_WRITE_ERROR);