init_flush_request() only set REQ_FLUSH when initializing flush
requests making them READ requests.  Use WRITE_FLUSH instead.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Mike Snitzer <redacted>
---
So, this was the culprit for the incorrect data direction for flush
requests.

Thanks.

 block/blk-flush.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: block/block/blk-flush.c
===================================================================

--- block.orig/block/blk-flush.c
+++ block/block/blk-flush.c

@@ -77,7 +77,7 @@ static void post_flush_end_io(struct req
 static void init_flush_request(struct request *rq, struct gendisk *disk)
 {
 	rq->cmd_type = REQ_TYPE_FS;
-	rq->cmd_flags = REQ_FLUSH;
+	rq->cmd_flags = WRITE_FLUSH;
 	rq->rq_disk = disk;
 }