From 088b70526d5b4080010147e4a6ae1252c3fc2228 Mon Sep 17 00:00:00 2001 From: Lars Ellenberg Date: Tue, 24 Mar 2015 21:46:29 +0100 Subject: drbd: fix queue limit setup for discard We cannot possibly support SECDISCARD, even if all backend devices would support it: if our peer is currently unreachable, some instance of the data may obviously still be recoverable. We did not set discard_granularity at all. We don't really care (yet), we only pass them on, so for now, set our granularity to one sector. blkdev_stack_limits() takes care of the rest. If we decide we cannot support discards, not only clear the (not user visible) QUEUE_FLAG_DISCARD, but set both (user visible) discard_granularity and max_discard_sectors to zero, to avoid confusion with e.g. lsblk -D. Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe --- drivers/block/drbd/drbd_nl.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) (limited to 'drivers/block') diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c index 5e4adff91d1d..4703f1ad7f92 100644 --- a/drivers/block/drbd/drbd_nl.c +++ b/drivers/block/drbd/drbd_nl.c @@ -1168,21 +1168,20 @@ static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backi if (b) { struct drbd_connection *connection = first_peer_device(device)->connection; + blk_queue_max_discard_sectors(q, DRBD_MAX_DISCARD_SECTORS); + if (blk_queue_discard(b) && (connection->cstate < C_CONNECTED || connection->agreed_features & FF_TRIM)) { - /* For now, don't allow more than one activity log extent worth of data - * to be discarded in one go. We may need to rework drbd_al_begin_io() - * to allow for even larger discard ranges */ - blk_queue_max_discard_sectors(q, DRBD_MAX_DISCARD_SECTORS); - + /* We don't care, stacking below should fix it for the local device. + * Whether or not it is a suitable granularity on the remote device + * is not our problem, really. If you care, you need to + * use devices with similar topology on all peers. */ + q->limits.discard_granularity = 512; queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q); - /* REALLY? Is stacking secdiscard "legal"? */ - if (blk_queue_secdiscard(b)) - queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD, q); } else { blk_queue_max_discard_sectors(q, 0); queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q); - queue_flag_clear_unlocked(QUEUE_FLAG_SECDISCARD, q); + q->limits.discard_granularity = 0; } blk_queue_stack_limits(q, b); @@ -1194,6 +1193,12 @@ static void drbd_setup_queue_param(struct drbd_device *device, struct drbd_backi q->backing_dev_info.ra_pages = b->backing_dev_info.ra_pages; } } + /* To avoid confusion, if this queue does not support discard, clear + * max_discard_sectors, which is what lsblk -D reports to the user. */ + if (!blk_queue_discard(q)) { + blk_queue_max_discard_sectors(q, 0); + q->limits.discard_granularity = 0; + } } void drbd_reconsider_max_bio_size(struct drbd_device *device, struct drbd_backing_dev *bdev) -- cgit v1.2.3