From 589d7ed02ade0d06a3510da2e15a7edfdb2ef3d8 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 3 Sep 2010 11:56:16 +0200 Subject: block/loop: queue ordered mode should be DRAIN_FLUSH loop implements FLUSH using fsync but was incorrectly setting its ordered mode to DRAIN. Change it to DRAIN_FLUSH. In practice, this doesn't change anything as loop doesn't make use of the block layer ordered implementation. Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe --- drivers/block/loop.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/block') diff --git a/drivers/block/loop.c b/drivers/block/loop.c index f3c636d2371..c3a4a2e176d 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -832,7 +832,7 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode, lo->lo_queue->unplug_fn = loop_unplug; if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync) - blk_queue_ordered(lo->lo_queue, QUEUE_ORDERED_DRAIN); + blk_queue_ordered(lo->lo_queue, QUEUE_ORDERED_DRAIN_FLUSH); set_capacity(lo->lo_disk, size); bd_set_size(bdev, size << 9); -- cgit v1.2.3-18-g5258 From 6958f145459ca7ad9715024de97445addacb8510 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 3 Sep 2010 11:56:16 +0200 Subject: block: kill QUEUE_ORDERED_BY_TAG Nobody is making meaningful use of ORDERED_BY_TAG now and queue draining for barrier requests will be removed soon which will render the advantage of tag ordering moot. Kill ORDERED_BY_TAG. The following users are affected. * brd: converted to ORDERED_DRAIN. * virtio_blk: ORDERED_TAG path was already marked deprecated. Removed. * xen-blkfront: ORDERED_TAG case dropped. Signed-off-by: Tejun Heo Cc: Christoph Hellwig Cc: Nick Piggin Cc: Michael S. Tsirkin Cc: Jeremy Fitzhardinge Cc: Chris Wright Signed-off-by: Jens Axboe --- drivers/block/brd.c | 2 +- drivers/block/virtio_blk.c | 9 --------- drivers/block/xen-blkfront.c | 8 +++----- 3 files changed, 4 insertions(+), 15 deletions(-) (limited to 'drivers/block') diff --git a/drivers/block/brd.c b/drivers/block/brd.c index 1c7f63792ff..47a41272d26 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -482,7 +482,7 @@ static struct brd_device *brd_alloc(int i) if (!brd->brd_queue) goto out_free_dev; blk_queue_make_request(brd->brd_queue, brd_make_request); - blk_queue_ordered(brd->brd_queue, QUEUE_ORDERED_TAG); + blk_queue_ordered(brd->brd_queue, QUEUE_ORDERED_DRAIN); blk_queue_max_hw_sectors(brd->brd_queue, 1024); blk_queue_bounce_limit(brd->brd_queue, BLK_BOUNCE_ANY); diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 2aafafca2b1..79652809eee 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -395,15 +395,6 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) * to implement write barrier support. */ blk_queue_ordered(q, QUEUE_ORDERED_DRAIN_FLUSH); - } else if (virtio_has_feature(vdev, VIRTIO_BLK_F_BARRIER)) { - /* - * If the BARRIER feature is supported the host expects us - * to order request by tags. This implies there is not - * volatile write cache on the host, and that the host - * never re-orders outstanding I/O. This feature is not - * useful for real life scenarious and deprecated. - */ - blk_queue_ordered(q, QUEUE_ORDERED_TAG); } else { /* * If the FLUSH feature is not supported we must assume that diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index ac1b682edec..50ec6f83499 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -424,8 +424,7 @@ static int xlvbd_barrier(struct blkfront_info *info) const char *barrier; switch (info->feature_barrier) { - case QUEUE_ORDERED_DRAIN: barrier = "enabled (drain)"; break; - case QUEUE_ORDERED_TAG: barrier = "enabled (tag)"; break; + case QUEUE_ORDERED_DRAIN: barrier = "enabled"; break; case QUEUE_ORDERED_NONE: barrier = "disabled"; break; default: return -EINVAL; } @@ -1078,8 +1077,7 @@ static void blkfront_connect(struct blkfront_info *info) * we're dealing with a very old backend which writes * synchronously; draining will do what needs to get done. * - * If there are barriers, then we can do full queued writes - * with tagged barriers. + * If there are barriers, then we use flush. * * If barriers are not supported, then there's no much we can * do, so just set ordering to NONE. @@ -1087,7 +1085,7 @@ static void blkfront_connect(struct blkfront_info *info) if (err) info->feature_barrier = QUEUE_ORDERED_DRAIN; else if (barrier) - info->feature_barrier = QUEUE_ORDERED_TAG; + info->feature_barrier = QUEUE_ORDERED_DRAIN_FLUSH; else info->feature_barrier = QUEUE_ORDERED_NONE; -- cgit v1.2.3-18-g5258 From 4913efe456c987057e5d36a3f0a55422a9072cae Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 3 Sep 2010 11:56:16 +0200 Subject: block: deprecate barrier and replace blk_queue_ordered() with blk_queue_flush() Barrier is deemed too heavy and will soon be replaced by FLUSH/FUA requests. Deprecate barrier. All REQ_HARDBARRIERs are failed with -EOPNOTSUPP and blk_queue_ordered() is replaced with simpler blk_queue_flush(). blk_queue_flush() takes combinations of REQ_FLUSH and FUA. If a device has write cache and can flush it, it should set REQ_FLUSH. If the device can handle FUA writes, it should also set REQ_FUA. All blk_queue_ordered() users are converted. * ORDERED_DRAIN is mapped to 0 which is the default value. * ORDERED_DRAIN_FLUSH is mapped to REQ_FLUSH. * ORDERED_DRAIN_FLUSH_FUA is mapped to REQ_FLUSH | REQ_FUA. Signed-off-by: Tejun Heo Acked-by: Boaz Harrosh Cc: Christoph Hellwig Cc: Nick Piggin Cc: Michael S. Tsirkin Cc: Jeremy Fitzhardinge Cc: Chris Wright Cc: FUJITA Tomonori Cc: Geert Uytterhoeven Cc: David S. Miller Cc: Alasdair G Kergon Cc: Pierre Ossman Cc: Stefan Weinhuber Signed-off-by: Jens Axboe --- drivers/block/brd.c | 1 - drivers/block/loop.c | 2 +- drivers/block/osdblk.c | 2 +- drivers/block/ps3disk.c | 2 +- drivers/block/virtio_blk.c | 25 +++++++++---------------- drivers/block/xen-blkfront.c | 43 ++++++++++++------------------------------- 6 files changed, 24 insertions(+), 51 deletions(-) (limited to 'drivers/block') diff --git a/drivers/block/brd.c b/drivers/block/brd.c index 47a41272d26..fa33f97722b 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -482,7 +482,6 @@ static struct brd_device *brd_alloc(int i) if (!brd->brd_queue) goto out_free_dev; blk_queue_make_request(brd->brd_queue, brd_make_request); - blk_queue_ordered(brd->brd_queue, QUEUE_ORDERED_DRAIN); blk_queue_max_hw_sectors(brd->brd_queue, 1024); blk_queue_bounce_limit(brd->brd_queue, BLK_BOUNCE_ANY); diff --git a/drivers/block/loop.c b/drivers/block/loop.c index c3a4a2e176d..953d1e12f4d 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -832,7 +832,7 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode, lo->lo_queue->unplug_fn = loop_unplug; if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync) - blk_queue_ordered(lo->lo_queue, QUEUE_ORDERED_DRAIN_FLUSH); + blk_queue_flush(lo->lo_queue, REQ_FLUSH); set_capacity(lo->lo_disk, size); bd_set_size(bdev, size << 9); diff --git a/drivers/block/osdblk.c b/drivers/block/osdblk.c index 2284b4f05c6..72d62462433 100644 --- a/drivers/block/osdblk.c +++ b/drivers/block/osdblk.c @@ -439,7 +439,7 @@ static int osdblk_init_disk(struct osdblk_device *osdev) blk_queue_stack_limits(q, osd_request_queue(osdev->osd)); blk_queue_prep_rq(q, blk_queue_start_tag); - blk_queue_ordered(q, QUEUE_ORDERED_DRAIN_FLUSH); + blk_queue_flush(q, REQ_FLUSH); disk->queue = q; diff --git a/drivers/block/ps3disk.c b/drivers/block/ps3disk.c index e9da874d041..4911f9e57bc 100644 --- a/drivers/block/ps3disk.c +++ b/drivers/block/ps3disk.c @@ -468,7 +468,7 @@ static int __devinit ps3disk_probe(struct ps3_system_bus_device *_dev) blk_queue_dma_alignment(queue, dev->blk_size-1); blk_queue_logical_block_size(queue, dev->blk_size); - blk_queue_ordered(queue, QUEUE_ORDERED_DRAIN_FLUSH); + blk_queue_flush(queue, REQ_FLUSH); blk_queue_max_segments(queue, -1); blk_queue_max_segment_size(queue, dev->bounce_size); diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 79652809eee..d10b635b394 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -388,22 +388,15 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) vblk->disk->driverfs_dev = &vdev->dev; index++; - if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH)) { - /* - * If the FLUSH feature is supported we do have support for - * flushing a volatile write cache on the host. Use that - * to implement write barrier support. - */ - blk_queue_ordered(q, QUEUE_ORDERED_DRAIN_FLUSH); - } else { - /* - * If the FLUSH feature is not supported we must assume that - * the host does not perform any kind of volatile write - * caching. We still need to drain the queue to provider - * proper barrier semantics. - */ - blk_queue_ordered(q, QUEUE_ORDERED_DRAIN); - } + /* + * If the FLUSH feature is supported we do have support for + * flushing a volatile write cache on the host. Use that to + * implement write barrier support; otherwise, we must assume + * that the host does not perform any kind of volatile write + * caching. + */ + if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH)) + blk_queue_flush(q, REQ_FLUSH); /* If disk is read-only in the host, the guest should obey */ if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO)) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 50ec6f83499..0b1eea64326 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -95,7 +95,7 @@ struct blkfront_info struct gnttab_free_callback callback; struct blk_shadow shadow[BLK_RING_SIZE]; unsigned long shadow_free; - int feature_barrier; + unsigned int feature_flush; int is_ready; }; @@ -418,25 +418,12 @@ static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size) } -static int xlvbd_barrier(struct blkfront_info *info) +static void xlvbd_flush(struct blkfront_info *info) { - int err; - const char *barrier; - - switch (info->feature_barrier) { - case QUEUE_ORDERED_DRAIN: barrier = "enabled"; break; - case QUEUE_ORDERED_NONE: barrier = "disabled"; break; - default: return -EINVAL; - } - - err = blk_queue_ordered(info->rq, info->feature_barrier); - - if (err) - return err; - + blk_queue_flush(info->rq, info->feature_flush); printk(KERN_INFO "blkfront: %s: barriers %s\n", - info->gd->disk_name, barrier); - return 0; + info->gd->disk_name, + info->feature_flush ? "enabled" : "disabled"); } @@ -515,7 +502,7 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity, info->rq = gd->queue; info->gd = gd; - xlvbd_barrier(info); + xlvbd_flush(info); if (vdisk_info & VDISK_READONLY) set_disk_ro(gd, 1); @@ -661,8 +648,8 @@ 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; - info->feature_barrier = QUEUE_ORDERED_NONE; - xlvbd_barrier(info); + info->feature_flush = 0; + xlvbd_flush(info); } /* fall through */ case BLKIF_OP_READ: @@ -1075,19 +1062,13 @@ static void blkfront_connect(struct blkfront_info *info) /* * If there's no "feature-barrier" defined, then it means * we're dealing with a very old backend which writes - * synchronously; draining will do what needs to get done. + * synchronously; nothing to do. * * If there are barriers, then we use flush. - * - * If barriers are not supported, then there's no much we can - * do, so just set ordering to NONE. */ - if (err) - info->feature_barrier = QUEUE_ORDERED_DRAIN; - else if (barrier) - info->feature_barrier = QUEUE_ORDERED_DRAIN_FLUSH; - else - info->feature_barrier = QUEUE_ORDERED_NONE; + info->feature_flush = 0; + if (!err && barrier) + info->feature_flush = REQ_FLUSH; err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size); if (err) { -- cgit v1.2.3-18-g5258 From 9cbbdca44ae1a6f512ea1e2be11ced8bbb9d430a Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 3 Sep 2010 11:56:16 +0200 Subject: block: remove spurious uses of REQ_HARDBARRIER REQ_HARDBARRIER is deprecated. Remove spurious uses in the following users. Please note that other than osdblk, all other uses were already spurious before deprecation. * osdblk: osdblk_rq_fn() won't receive any request with REQ_HARDBARRIER set. Remove the test for it. * pktcdvd: use of REQ_HARDBARRIER in pkt_generic_packet() doesn't mean anything. Removed. * aic7xxx_old: Setting MSG_ORDERED_Q_TAG on REQ_HARDBARRIER is spurious. Removed. * sas_scsi_host: Setting TASK_ATTR_ORDERED on REQ_HARDBARRIER is spurious. Removed. * scsi_tcq: The ordered tag path wasn't being used anyway. Removed. Signed-off-by: Tejun Heo Acked-by: Boaz Harrosh Cc: James Bottomley Cc: Peter Osterlund Signed-off-by: Jens Axboe --- drivers/block/osdblk.c | 3 +-- drivers/block/pktcdvd.c | 1 - 2 files changed, 1 insertion(+), 3 deletions(-) (limited to 'drivers/block') diff --git a/drivers/block/osdblk.c b/drivers/block/osdblk.c index 72d62462433..87311ebac0d 100644 --- a/drivers/block/osdblk.c +++ b/drivers/block/osdblk.c @@ -310,8 +310,7 @@ static void osdblk_rq_fn(struct request_queue *q) break; /* filter out block requests we don't understand */ - if (rq->cmd_type != REQ_TYPE_FS && - !(rq->cmd_flags & REQ_HARDBARRIER)) { + if (rq->cmd_type != REQ_TYPE_FS) { blk_end_request_all(rq, 0); continue; } diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c index b1cbeb59bb7..0166ea13604 100644 --- a/drivers/block/pktcdvd.c +++ b/drivers/block/pktcdvd.c @@ -753,7 +753,6 @@ static int pkt_generic_packet(struct pktcdvd_device *pd, struct packet_command * rq->timeout = 60*HZ; rq->cmd_type = REQ_TYPE_BLOCK_PC; - rq->cmd_flags |= REQ_HARDBARRIER; if (cgc->quiet) rq->cmd_flags |= REQ_QUIET; -- cgit v1.2.3-18-g5258 From 6259f28459a9de820f47a9ece4ffa22d4596a9af Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 3 Sep 2010 11:56:17 +0200 Subject: block/loop: implement REQ_FLUSH/FUA support Deprecate REQ_HARDBARRIER and implement REQ_FLUSH/FUA instead. Also, instead of checking file->f_op->fsync() directly, look at the value of vfs_fsync() and ignore -EINVAL return. Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe --- drivers/block/loop.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) (limited to 'drivers/block') diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 953d1e12f4d..5d27bc6596d 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -477,17 +477,17 @@ static int do_bio_filebacked(struct loop_device *lo, struct bio *bio) pos = ((loff_t) bio->bi_sector << 9) + lo->lo_offset; if (bio_rw(bio) == WRITE) { - bool barrier = (bio->bi_rw & REQ_HARDBARRIER); struct file *file = lo->lo_backing_file; - if (barrier) { - if (unlikely(!file->f_op->fsync)) { - ret = -EOPNOTSUPP; - goto out; - } + /* REQ_HARDBARRIER is deprecated */ + if (bio->bi_rw & REQ_HARDBARRIER) { + ret = -EOPNOTSUPP; + goto out; + } + if (bio->bi_rw & REQ_FLUSH) { ret = vfs_fsync(file, 0); - if (unlikely(ret)) { + if (unlikely(ret && ret != -EINVAL)) { ret = -EIO; goto out; } @@ -495,9 +495,9 @@ static int do_bio_filebacked(struct loop_device *lo, struct bio *bio) ret = lo_send(lo, bio, pos); - if (barrier && !ret) { + if ((bio->bi_rw & REQ_FUA) && !ret) { ret = vfs_fsync(file, 0); - if (unlikely(ret)) + if (unlikely(ret && ret != -EINVAL)) ret = -EIO; } } else -- cgit v1.2.3-18-g5258 From 02c42b7a68695c2c3e3fecf9f6b9a4ea43abe52f Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 3 Sep 2010 11:56:18 +0200 Subject: virtio_blk: drop REQ_HARDBARRIER support Remove now unused REQ_HARDBARRIER support. virtio_blk already supports REQ_FLUSH and the usefulness of REQ_FUA for virtio_blk is questionable at this point, so there's nothing else to do to support new REQ_FLUSH/FUA interface. Signed-off-by: Tejun Heo Cc: Michael S. Tsirkin Cc: Christoph Hellwig Signed-off-by: Jens Axboe --- drivers/block/virtio_blk.c | 17 ++++------------- 1 file changed, 4 insertions(+), 13 deletions(-) (limited to 'drivers/block') diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index d10b635b394..126062802cb 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -128,9 +128,6 @@ static bool do_req(struct request_queue *q, struct virtio_blk *vblk, } } - if (vbr->req->cmd_flags & REQ_HARDBARRIER) - vbr->out_hdr.type |= VIRTIO_BLK_T_BARRIER; - sg_set_buf(&vblk->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr)); /* @@ -388,13 +385,7 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) vblk->disk->driverfs_dev = &vdev->dev; index++; - /* - * If the FLUSH feature is supported we do have support for - * flushing a volatile write cache on the host. Use that to - * implement write barrier support; otherwise, we must assume - * that the host does not perform any kind of volatile write - * caching. - */ + /* configure queue flush support */ if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH)) blk_queue_flush(q, REQ_FLUSH); @@ -515,9 +506,9 @@ static const struct virtio_device_id id_table[] = { }; static unsigned int features[] = { - VIRTIO_BLK_F_BARRIER, VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, - VIRTIO_BLK_F_GEOMETRY, VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, - VIRTIO_BLK_F_SCSI, VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY + VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY, + VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_SCSI, + VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY }; /* -- cgit v1.2.3-18-g5258 From dd3932eddf428571762596e17b65f5dc92ca361b Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 16 Sep 2010 20:51:46 +0200 Subject: block: remove BLKDEV_IFL_WAIT All the blkdev_issue_* helpers can only sanely be used for synchronous caller. To issue cache flushes or barriers asynchronously the caller needs to set up a bio by itself with a completion callback to move the asynchronous state machine ahead. So drop the BLKDEV_IFL_WAIT flag that is always specified when calling blkdev_issue_* and also remove the now unused flags argument to blkdev_issue_flush and blkdev_issue_zeroout. For blkdev_issue_discard we need to keep it for the secure discard flag, which gains a more descriptive name and loses the bitops vs flag confusion. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- drivers/block/drbd/drbd_int.h | 3 +-- drivers/block/drbd/drbd_receiver.c | 2 +- 2 files changed, 2 insertions(+), 3 deletions(-) (limited to 'drivers/block') diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h index 352441b0f92..c2ef476f571 100644 --- a/drivers/block/drbd/drbd_int.h +++ b/drivers/block/drbd/drbd_int.h @@ -2321,8 +2321,7 @@ static inline void drbd_md_flush(struct drbd_conf *mdev) if (test_bit(MD_NO_BARRIER, &mdev->flags)) return; - r = blkdev_issue_flush(mdev->ldev->md_bdev, GFP_KERNEL, NULL, - BLKDEV_IFL_WAIT); + r = blkdev_issue_flush(mdev->ldev->md_bdev, GFP_KERNEL, NULL); if (r) { set_bit(MD_NO_BARRIER, &mdev->flags); dev_err(DEV, "meta data flush failed with status %d, disabling md-flushes\n", r); diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c index 081522d3c74..df15e7f0e7b 100644 --- a/drivers/block/drbd/drbd_receiver.c +++ b/drivers/block/drbd/drbd_receiver.c @@ -975,7 +975,7 @@ static enum finish_epoch drbd_flush_after_epoch(struct drbd_conf *mdev, struct d if (mdev->write_ordering >= WO_bdev_flush && get_ldev(mdev)) { rv = blkdev_issue_flush(mdev->ldev->backing_bdev, GFP_KERNEL, - NULL, BLKDEV_IFL_WAIT); + NULL); if (rv) { dev_err(DEV, "local disk flush failed with status %d\n", rv); /* would rather check on EOPNOTSUPP, but that is not reliable. -- cgit v1.2.3-18-g5258 From 005a1d15f5a6b2bb4ada80349513effbf22b4588 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Fri, 22 Oct 2010 10:58:33 +0200 Subject: xen-blkfront: disable barrier/flush write support The driver doesn't handle empty flushes. Disable barrier/flush write support until this is fixed up. Signed-off-by: Jens Axboe --- drivers/block/xen-blkfront.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'drivers/block') diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index f2ffc46644d..739b4c1416e 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -1067,8 +1067,15 @@ static void blkfront_connect(struct blkfront_info *info) * If there are barriers, then we use flush. */ 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 err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size); if (err) { -- cgit v1.2.3-18-g5258