Commit be2f8373 authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge
Browse files

xen/blkfront: Implement FUA with BLKIF_OP_WRITE_BARRIER 



The BLKIF_OP_WRITE_BARRIER is a full ordered barrier, so we can use it
to implement FUA as well as a plain FLUSH.

Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: default avatarChristoph Hellwig <hch@lst.de>
parent a945b980

drivers/block/xen-blkfront.c

+12 −2
Original line number Diff line number Diff line
@@ -286,8 +286,18 @@ static int blkif_queue_request(struct request *req) 


	ring_req->operation = rq_data_dir(req) ?

		BLKIF_OP_WRITE : BLKIF_OP_READ;

	if (req->cmd_flags & REQ_FLUSH)



	if (req->cmd_flags & (REQ_FLUSH | REQ_FUA)) {

		/*

		 * Ideally we could just do an unordered

		 * flush-to-disk, but all we have is a full write

		 * barrier at the moment.  However, a barrier write is

		 * a superset of FUA, so we can implement it the same

		 * way.  (It's also a FLUSH+FUA, since it is

		 * guaranteed ordered WRT previous writes.)

		 */

		ring_req->operation = BLKIF_OP_WRITE_BARRIER;

	}



	ring_req->nr_segments = blk_rq_map_sg(req->q, req, info->sg);

	BUG_ON(ring_req->nr_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);
@@ -1065,7 +1075,7 @@ static void blkfront_connect(struct blkfront_info *info) 
	info->feature_flush = 0;



	if (!err && barrier)

		info->feature_flush = REQ_FLUSH;

		info->feature_flush = REQ_FLUSH | REQ_FUA;



	err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size);

	if (err) {