From 9de7e14a1a9c6bc4f9be6ccd9b951341a80dbd52 Mon Sep 17 00:00:00 2001 From: Lars Ellenberg Date: Tue, 29 Aug 2017 10:20:38 +0200 Subject: [PATCH] drbd: new disk-option disable-write-same Some backend devices claim to support write-same, but would fail actual write-same requests. Allow to set (or toggle) whether or not DRBD tries to support write-same. Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe --- drivers/block/drbd/drbd_nl.c | 15 ++++++++++++--- include/linux/drbd_genl.h | 3 ++- include/linux/drbd_limits.h | 8 +++++++- 3 files changed, 21 insertions(+), 5 deletions(-) diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c index ad0fcb4..c383b6c 100644 --- a/drivers/block/drbd/drbd_nl.c +++ b/drivers/block/drbd/drbd_nl.c @@ -1236,12 +1236,18 @@ static void fixup_discard_if_not_supported(struct request_queue *q) static void decide_on_write_same_support(struct drbd_device *device, struct request_queue *q, - struct request_queue *b, struct o_qlim *o) + struct request_queue *b, struct o_qlim *o, + bool disable_write_same) { struct drbd_peer_device *peer_device = first_peer_device(device); struct drbd_connection *connection = peer_device->connection; bool can_do = b ? b->limits.max_write_same_sectors : true; + if (can_do && disable_write_same) { + can_do = false; + drbd_info(peer_device, "WRITE_SAME disabled by config\n"); + } + if (can_do && connection->cstate >= C_CONNECTED && !(connection->agreed_features & DRBD_FF_WSAME)) { can_do = false; drbd_info(peer_device, "peer does not support WRITE_SAME\n"); @@ -1302,6 +1308,7 @@ static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backi struct request_queue *b = NULL; struct disk_conf *dc; bool discard_zeroes_if_aligned = true; + bool disable_write_same = false; if (bdev) { b = bdev->backing_bdev->bd_disk->queue; @@ -1311,6 +1318,7 @@ static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backi dc = rcu_dereference(device->ldev->disk_conf); max_segments = dc->max_bio_bvecs; discard_zeroes_if_aligned = dc->discard_zeroes_if_aligned; + disable_write_same = dc->disable_write_same; rcu_read_unlock(); blk_set_stacking_limits(&q->limits); @@ -1321,7 +1329,7 @@ static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backi blk_queue_max_segments(q, max_segments ? max_segments : BLK_MAX_SEGMENTS); blk_queue_segment_boundary(q, PAGE_SIZE-1); decide_on_discard_support(device, q, b, discard_zeroes_if_aligned); - decide_on_write_same_support(device, q, b, o); + decide_on_write_same_support(device, q, b, o, disable_write_same); if (b) { blk_queue_stack_limits(q, b); @@ -1612,7 +1620,8 @@ int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info) if (write_ordering_changed(old_disk_conf, new_disk_conf)) drbd_bump_write_ordering(device->resource, NULL, WO_BDEV_FLUSH); - if (old_disk_conf->discard_zeroes_if_aligned != new_disk_conf->discard_zeroes_if_aligned) + if (old_disk_conf->discard_zeroes_if_aligned != new_disk_conf->discard_zeroes_if_aligned + || old_disk_conf->disable_write_same != new_disk_conf->disable_write_same) drbd_reconsider_queue_parameters(device, device->ldev, NULL); drbd_md_sync(device); diff --git a/include/linux/drbd_genl.h b/include/linux/drbd_genl.h index 2896f93..4e6d4d4 100644 --- a/include/linux/drbd_genl.h +++ b/include/linux/drbd_genl.h @@ -132,7 +132,8 @@ GENL_struct(DRBD_NLA_DISK_CONF, 3, disk_conf, __flg_field_def(18, DRBD_GENLA_F_MANDATORY, disk_drain, DRBD_DISK_DRAIN_DEF) __flg_field_def(19, DRBD_GENLA_F_MANDATORY, md_flushes, DRBD_MD_FLUSHES_DEF) __flg_field_def(23, 0 /* OPTIONAL */, al_updates, DRBD_AL_UPDATES_DEF) - __flg_field_def(24, 0 /* OPTIONAL */, discard_zeroes_if_aligned, DRBD_DISCARD_ZEROES_IF_ALIGNED) + __flg_field_def(24, 0 /* OPTIONAL */, discard_zeroes_if_aligned, DRBD_DISCARD_ZEROES_IF_ALIGNED_DEF) + __flg_field_def(26, 0 /* OPTIONAL */, disable_write_same, DRBD_DISABLE_WRITE_SAME_DEF) ) GENL_struct(DRBD_NLA_RESOURCE_OPTS, 4, res_opts, diff --git a/include/linux/drbd_limits.h b/include/linux/drbd_limits.h index ddac684..24ae1b9 100644 --- a/include/linux/drbd_limits.h +++ b/include/linux/drbd_limits.h @@ -209,12 +209,18 @@ #define DRBD_MD_FLUSHES_DEF 1 #define DRBD_TCP_CORK_DEF 1 #define DRBD_AL_UPDATES_DEF 1 + /* We used to ignore the discard_zeroes_data setting. * To not change established (and expected) behaviour, * by default assume that, for discard_zeroes_data=0, * we can make that an effective discard_zeroes_data=1, * if we only explicitly zero-out unaligned partial chunks. */ -#define DRBD_DISCARD_ZEROES_IF_ALIGNED 1 +#define DRBD_DISCARD_ZEROES_IF_ALIGNED_DEF 1 + +/* Some backends pretend to support WRITE SAME, + * but fail such requests when they are actually submitted. + * This is to tell DRBD to not even try. */ +#define DRBD_DISABLE_WRITE_SAME_DEF 0 #define DRBD_ALLOW_TWO_PRIMARIES_DEF 0 #define DRBD_ALWAYS_ASBP_DEF 0 -- 2.7.4