1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index b5e56af..f4f7d35 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -800,6 +800,15 @@ static int dm_request(request_queue_t *q, struct bio *bio)
 	int rw = bio_data_dir(bio);
 	struct mapped_device *md = q->queuedata;
 
+	/*
+	 * There is no use in forwarding any barrier request since we can't
+	 * guarantee it is (or can be) handled by the targets correctly.
+	 */
+	if (unlikely(bio_barrier(bio))) {
+		bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
+		return 0;
+	}
+
 	down_read(&md->io_lock);
 
 	disk_stat_inc(dm_disk(md), ios[rw]);