diff --git a/block/blk-merge.c b/block/blk-merge.c
index 39ce644..e199967 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -350,6 +350,12 @@
 	if (blk_integrity_rq(req) != blk_integrity_rq(next))
 		return 0;
 
+	/* don't merge requests of different failfast settings */
+	if (blk_failfast_dev(req)	!= blk_failfast_dev(next)	||
+	    blk_failfast_transport(req)	!= blk_failfast_transport(next)	||
+	    blk_failfast_driver(req)	!= blk_failfast_driver(next))
+		return 0;
+
 	/*
 	 * If we are allowed to merge, then append bio list
 	 * from next to rq and release next. merge_requests_fn
diff --git a/block/elevator.c b/block/elevator.c
index ca86192..6f23753 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -100,6 +100,14 @@
 	if (bio_integrity(bio) != blk_integrity_rq(rq))
 		return 0;
 
+	/*
+	 * Don't merge if failfast settings don't match
+	 */
+	if (bio_failfast_dev(bio)	!= blk_failfast_dev(rq)		||
+	    bio_failfast_transport(bio)	!= blk_failfast_transport(rq)	||
+	    bio_failfast_driver(bio)	!= blk_failfast_driver(rq))
+		return 0;
+
 	if (!elv_iosched_allow_merge(rq, bio))
 		return 0;