The patch below does not apply to the 5.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From e0910c8e4f87bb9f767e61a778b0d9271c4dc512 Mon Sep 17 00:00:00 2001
From: Mike Snitzer snitzer@redhat.com Date: Thu, 24 Sep 2020 13:14:52 -0400 Subject: [PATCH] dm raid: fix discard limits for raid1 and raid10
Block core warned that discard_granularity was 0 for dm-raid with personality of raid1. Reason is that raid_io_hints() was incorrectly special-casing raid1 rather than raid0.
But since commit 29efc390b9462 ("md/md0: optimize raid0 discard handling") even raid0 properly handles large discards.
Fix raid_io_hints() by removing discard limits settings for raid1. Also, fix limits for raid10 by properly stacking underlying limits as done in blk_stack_limits().
Depends-on: 29efc390b9462 ("md/md0: optimize raid0 discard handling") Fixes: 61697a6abd24a ("dm: eliminate 'split_discard_bios' flag from DM target interface") Cc: stable@vger.kernel.org Reported-by: Zdenek Kabelac zkabelac@redhat.com Reported-by: Mikulas Patocka mpatocka@redhat.com Signed-off-by: Mike Snitzer snitzer@redhat.com
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c index 56b723d012ac..dc8568ab96f2 100644 --- a/drivers/md/dm-raid.c +++ b/drivers/md/dm-raid.c @@ -3730,12 +3730,14 @@ static void raid_io_hints(struct dm_target *ti, struct queue_limits *limits) blk_limits_io_opt(limits, chunk_size_bytes * mddev_data_stripes(rs));
/* - * RAID1 and RAID10 personalities require bio splitting, - * RAID0/4/5/6 don't and process large discard bios properly. + * RAID10 personality requires bio splitting, + * RAID0/1/4/5/6 don't and process large discard bios properly. */ - if (rs_is_raid1(rs) || rs_is_raid10(rs)) { - limits->discard_granularity = chunk_size_bytes; - limits->max_discard_sectors = rs->md.chunk_sectors; + if (rs_is_raid10(rs)) { + limits->discard_granularity = max(chunk_size_bytes, + limits->discard_granularity); + limits->max_discard_sectors = min_not_zero(rs->md.chunk_sectors, + limits->max_discard_sectors); } }