This is a note to let you know that I've just added the patch titled dm raid: fix discard limits for raid1 and raid10 to the 5.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: dm-raid-fix-discard-limits-for-raid1-and-raid10.patch and it can be found in the queue-5.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From e0910c8e4f87bb9f767e61a778b0d9271c4dc512 Mon Sep 17 00:00:00 2001 From: Mike Snitzer <snitzer@xxxxxxxxxx> Date: Thu, 24 Sep 2020 13:14:52 -0400 Subject: dm raid: fix discard limits for raid1 and raid10 From: Mike Snitzer <snitzer@xxxxxxxxxx> commit e0910c8e4f87bb9f767e61a778b0d9271c4dc512 upstream. 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@xxxxxxxxxxxxxxx Reported-by: Zdenek Kabelac <zkabelac@xxxxxxxxxx> Reported-by: Mikulas Patocka <mpatocka@xxxxxxxxxx> Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/md/dm-raid.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) --- a/drivers/md/dm-raid.c +++ b/drivers/md/dm-raid.c @@ -3730,12 +3730,14 @@ static void raid_io_hints(struct dm_targ 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); } } Patches currently in stable-queue which might be from snitzer@xxxxxxxxxx are queue-5.9/md-change-mddev-chunk_sectors-from-int-to-unsigned.patch queue-5.9/dm-raid-fix-discard-limits-for-raid1-and-raid10.patch