[PATCH v4 2/4] blk-flush: fix rq->flush.seq for post-flush requests

[chengming . zhou]

From: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>

If the policy == (REQ_FSEQ_DATA | REQ_FSEQ_POSTFLUSH), it means that the
data sequence and post-flush sequence need to be done for this request.

The rq->flush.seq should record what sequences have been done (or don't
need to be done). So in this case, pre-flush doesn't need to be done,
we should init rq->flush.seq to REQ_FSEQ_PREFLUSH not REQ_FSEQ_POSTFLUSH.

Fixes: 615939a2ae73 ("blk-mq: defer to the normal submission path for post-flush requests")
Signed-off-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
---
 block/blk-flush.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/blk-flush.c b/block/blk-flush.c
index 8220517c2d67..fdc489e0ea16 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -443,7 +443,7 @@ bool blk_insert_flush(struct request *rq)
 		 * the post flush, and then just pass the command on.
 		 */
 		blk_rq_init_flush(rq);
-		rq->flush.seq |= REQ_FSEQ_POSTFLUSH;
+		rq->flush.seq |= REQ_FSEQ_PREFLUSH;
 		spin_lock_irq(&fq->mq_flush_lock);
 		list_move_tail(&rq->flush.list, &fq->flush_data_in_flight);
 		spin_unlock_irq(&fq->mq_flush_lock);
-- 
2.41.0