diff options
| author | Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> | 2010-11-02 10:38:33 -0400 |
|---|---|---|
| committer | Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> | 2010-11-02 11:27:59 -0400 |
| commit | be2f8373c188ed1f5d36003c9928e4d695213080 (patch) | |
| tree | 9cc7d9db48770b2468705d275dcefae5f26c60d1 /drivers | |
| parent | a945b9801a9bfd4a98bcfd9f6656b5027b254e3f (diff) | |
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: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/block/xen-blkfront.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 31c8a643d10..76b874a7917 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -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) { |