diff --git a/block/blk-flush.c b/block/blk-flush.c
index c486b7aa62ee..1bdbb3d3e5f5 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -395,6 +395,13 @@ void blk_insert_flush(struct request *rq)
 	if (!(fflags & (1UL << QUEUE_FLAG_FUA)))
 		rq->cmd_flags &= ~REQ_FUA;
 
+	/*
+	 * REQ_PREFLUSH|REQ_FUA implies REQ_SYNC, so if we clear any
+	 * of those flags, we have to set REQ_SYNC to avoid skewing
+	 * the request accounting.
+	 */
+	rq->cmd_flags |= REQ_SYNC;
+
 	/*
 	 * An empty flush handed down from a stacking driver may
 	 * translate into nothing if the underlying device does not