diff --git a/[refs] b/[refs]
index 51fa7f6fd71d..d091c75ce561 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 2669b19fa4debcdd6a660ace1a124c0900f113e6
+refs/heads/master: f10d9f617a65905c556c3b37c9b9646ae7d04ed7
diff --git a/trunk/block/blk-barrier.c b/trunk/block/blk-barrier.c
index eefbde835308..557f69360b6a 100644
--- a/trunk/block/blk-barrier.c
+++ b/trunk/block/blk-barrier.c
@@ -310,6 +310,15 @@ int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask,
 	if (!q)
 		return -ENXIO;
 
+	/*
+	 * some block devices may not have their queue correctly set up here
+	 * (e.g. loop device without a backing file) and so issuing a flush
+	 * here will panic. Ensure there is a request function before issuing
+	 * the barrier.
+	 */
+	if (!q->make_request_fn)
+		return -ENXIO;
+
 	bio = bio_alloc(gfp_mask, 0);
 	bio->bi_end_io = bio_end_empty_barrier;
 	bio->bi_bdev = bdev;