diff options
Diffstat (limited to 'drivers/block')
| -rw-r--r-- | drivers/block/xen-blkfront.c | 55 |
1 files changed, 33 insertions, 22 deletions
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 255035c..4f9e22f 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -65,7 +65,7 @@ enum blkif_state { struct blk_shadow { struct blkif_request req; - unsigned long request; + struct request *request; unsigned long frame[BLKIF_MAX_SEGMENTS_PER_REQUEST]; }; @@ -136,7 +136,7 @@ static void add_id_to_freelist(struct blkfront_info *info, unsigned long id) { info->shadow[id].req.id = info->shadow_free; - info->shadow[id].request = 0; + info->shadow[id].request = NULL; info->shadow_free = id; } @@ -245,14 +245,11 @@ static int blkif_ioctl(struct block_device *bdev, fmode_t mode, } /* - * blkif_queue_request + * Generate a Xen blkfront IO request from a blk layer request. Reads + * and writes are handled as expected. Since we lack a loose flush + * request, we map flushes into a full ordered barrier. * - * request block io - * - * id: for guest use only. - * operation: BLKIF_OP_{READ,WRITE,PROBE} - * buffer: buffer to read/write into. this should be a - * virtual address in the guest os. + * @req: a request struct */ static int blkif_queue_request(struct request *req) { @@ -281,7 +278,7 @@ static int blkif_queue_request(struct request *req) /* Fill out a communications ring structure. */ ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt); id = get_id_from_freelist(info); - info->shadow[id].request = (unsigned long)req; + info->shadow[id].request = req; ring_req->id = id; ring_req->sector_number = (blkif_sector_t)blk_rq_pos(req); @@ -290,6 +287,18 @@ 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 | 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); @@ -634,7 +643,7 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id) bret = RING_GET_RESPONSE(&info->ring, i); id = bret->id; - req = (struct request *)info->shadow[id].request; + req = info->shadow[id].request; blkif_completion(&info->shadow[id]); @@ -647,6 +656,16 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id) printk(KERN_WARNING "blkfront: %s: write barrier op failed\n", info->gd->disk_name); error = -EOPNOTSUPP; + } + if (unlikely(bret->status == BLKIF_RSP_ERROR && + info->shadow[id].req.nr_segments == 0)) { + printk(KERN_WARNING "blkfront: %s: empty write barrier op failed\n", + info->gd->disk_name); + error = -EOPNOTSUPP; + } + if (unlikely(error)) { + if (error == -EOPNOTSUPP) + error = 0; info->feature_flush = 0; xlvbd_flush(info); } @@ -899,7 +918,7 @@ static int blkif_recover(struct blkfront_info *info) /* Stage 3: Find pending requests and requeue them. */ for (i = 0; i < BLK_RING_SIZE; i++) { /* Not in use? */ - if (copy[i].request == 0) + if (!copy[i].request) continue; /* Grab a request slot and copy shadow state into it. */ @@ -916,9 +935,7 @@ static int blkif_recover(struct blkfront_info *info) req->seg[j].gref, info->xbdev->otherend_id, pfn_to_mfn(info->shadow[req->id].frame[j]), - rq_data_dir( - (struct request *) - info->shadow[req->id].request)); + rq_data_dir(info->shadow[req->id].request)); info->shadow[req->id].req = *req; info->ring.req_prod_pvt++; @@ -1067,14 +1084,8 @@ static void blkfront_connect(struct blkfront_info *info) */ info->feature_flush = 0; - /* - * The driver doesn't properly handled empty flushes, so - * lets disable barrier support for now. - */ -#if 0 if (!err && barrier) - info->feature_flush = REQ_FLUSH; -#endif + info->feature_flush = REQ_FLUSH | REQ_FUA; err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size); if (err) { |
