From fbbf055692aeb25c54c49d9ca84532de836fbba0 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 17 Jun 2010 09:54:32 +0200 Subject: [PATCH] block: fix DISCARD_BARRIER requests Filesystems assume that DISCARD_BARRIER are full barriers, so that they don't have to track in-progress discard operation when submitting new I/O. But currently we only treat them as elevator barriers, which don't actually do the nessecary queue drains. Also remove the unlikely around both the DISCARD and BARRIER requests - the happen far too often for a static mispredict. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- block/blk-core.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index f84cce42fc58..3deca77e0254 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1149,13 +1149,10 @@ void init_request_from_bio(struct request *req, struct bio *bio) else req->cmd_flags |= bio->bi_rw & REQ_FAILFAST_MASK; - if (unlikely(bio_rw_flagged(bio, BIO_RW_DISCARD))) { + if (bio_rw_flagged(bio, BIO_RW_DISCARD)) req->cmd_flags |= REQ_DISCARD; - if (bio_rw_flagged(bio, BIO_RW_BARRIER)) - req->cmd_flags |= REQ_SOFTBARRIER; - } else if (unlikely(bio_rw_flagged(bio, BIO_RW_BARRIER))) + if (bio_rw_flagged(bio, BIO_RW_BARRIER)) req->cmd_flags |= REQ_HARDBARRIER; - if (bio_rw_flagged(bio, BIO_RW_SYNCIO)) req->cmd_flags |= REQ_RW_SYNC; if (bio_rw_flagged(bio, BIO_RW_META)) -- 2.11.4.GIT