From 0dbed96a3cc9786bc4814dab98a7218753bde934 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 5 Apr 2017 19:21:21 +0200 Subject: drbd: make intelligent use of blkdev_issue_zeroout drbd always wants its discard wire operations to zero the blocks, so use blkdev_issue_zeroout with the BLKDEV_ZERO_UNMAP flag instead of reinventing it poorly. Signed-off-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Signed-off-by: Jens Axboe --- drivers/block/drbd/drbd_receiver.c | 102 ++----------------------------------- 1 file changed, 4 insertions(+), 98 deletions(-) (limited to 'drivers/block/drbd/drbd_receiver.c') diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c index dc9a6dc..bc1d296 100644 --- a/drivers/block/drbd/drbd_receiver.c +++ b/drivers/block/drbd/drbd_receiver.c @@ -1448,108 +1448,14 @@ void drbd_bump_write_ordering(struct drbd_resource *resource, struct drbd_backin drbd_info(resource, "Method to ensure write ordering: %s\n", write_ordering_str[resource->write_ordering]); } -/* - * We *may* ignore the discard-zeroes-data setting, if so configured. - * - * Assumption is that it "discard_zeroes_data=0" is only because the backend - * may ignore partial unaligned discards. - * - * LVM/DM thin as of at least - * LVM version: 2.02.115(2)-RHEL7 (2015-01-28) - * Library version: 1.02.93-RHEL7 (2015-01-28) - * Driver version: 4.29.0 - * still behaves this way. - * - * For unaligned (wrt. alignment and granularity) or too small discards, - * we zero-out the initial (and/or) trailing unaligned partial chunks, - * but discard all the aligned full chunks. - * - * At least for LVM/DM thin, the result is effectively "discard_zeroes_data=1". - */ -int drbd_issue_discard_or_zero_out(struct drbd_device *device, sector_t start, unsigned int nr_sectors, bool discard) -{ - struct block_device *bdev = device->ldev->backing_bdev; - struct request_queue *q = bdev_get_queue(bdev); - sector_t tmp, nr; - unsigned int max_discard_sectors, granularity; - int alignment; - int err = 0; - - if (!discard) - goto zero_out; - - /* Zero-sector (unknown) and one-sector granularities are the same. */ - granularity = max(q->limits.discard_granularity >> 9, 1U); - alignment = (bdev_discard_alignment(bdev) >> 9) % granularity; - - max_discard_sectors = min(q->limits.max_discard_sectors, (1U << 22)); - max_discard_sectors -= max_discard_sectors % granularity; - if (unlikely(!max_discard_sectors)) - goto zero_out; - - if (nr_sectors < granularity) - goto zero_out; - - tmp = start; - if (sector_div(tmp, granularity) != alignment) { - if (nr_sectors < 2*granularity) - goto zero_out; - /* start + gran - (start + gran - align) % gran */ - tmp = start + granularity - alignment; - tmp = start + granularity - sector_div(tmp, granularity); - - nr = tmp - start; - err |= blkdev_issue_zeroout(bdev, start, nr, GFP_NOIO, - BLKDEV_ZERO_NOUNMAP); - nr_sectors -= nr; - start = tmp; - } - while (nr_sectors >= granularity) { - nr = min_t(sector_t, nr_sectors, max_discard_sectors); - err |= blkdev_issue_discard(bdev, start, nr, GFP_NOIO, - BLKDEV_ZERO_NOUNMAP); - nr_sectors -= nr; - start += nr; - } - zero_out: - if (nr_sectors) { - err |= blkdev_issue_zeroout(bdev, start, nr_sectors, GFP_NOIO, - BLKDEV_ZERO_NOUNMAP); - } - return err != 0; -} - -static bool can_do_reliable_discards(struct drbd_device *device) -{ - struct request_queue *q = bdev_get_queue(device->ldev->backing_bdev); - struct disk_conf *dc; - bool can_do; - - if (!blk_queue_discard(q)) - return false; - - if (q->limits.discard_zeroes_data) - return true; - - rcu_read_lock(); - dc = rcu_dereference(device->ldev->disk_conf); - can_do = dc->discard_zeroes_if_aligned; - rcu_read_unlock(); - return can_do; -} - static void drbd_issue_peer_discard(struct drbd_device *device, struct drbd_peer_request *peer_req) { - /* If the backend cannot discard, or does not guarantee - * read-back zeroes in discarded ranges, we fall back to - * zero-out. Unless configuration specifically requested - * otherwise. */ - if (!can_do_reliable_discards(device)) - peer_req->flags |= EE_IS_TRIM_USE_ZEROOUT; + struct block_device *bdev = device->ldev->backing_bdev; - if (drbd_issue_discard_or_zero_out(device, peer_req->i.sector, - peer_req->i.size >> 9, !(peer_req->flags & EE_IS_TRIM_USE_ZEROOUT))) + if (blkdev_issue_zeroout(bdev, peer_req->i.sector, peer_req->i.size >> 9, + GFP_NOIO, 0)) peer_req->flags |= EE_WAS_ERROR; + drbd_endio_write_sec_final(peer_req); } -- cgit v1.1