This is a note to let you know that I've just added the patch titled

dm raid: fix raid set size revalidation

to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: dm-raid-fix-raid-set-size-revalidation.patch and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Fri Mar 16 15:11:08 CET 2018

From: Heinz Mauelshagen heinzm@redhat.com Date: Sat, 2 Dec 2017 01:03:51 +0100 Subject: dm raid: fix raid set size revalidation

From: Heinz Mauelshagen heinzm@redhat.com

[ Upstream commit 61e06e2c3ebd986050958513bfa40dceed756f8f ]

The raid set size is being revalidated unconditionally before a reshaping conversion is started. MD requires the size to only be reduced in case of a stripe removing (i.e. shrinking) reshape but not when growing because the raid array has to stay small until after the growing reshape finishes.

Fix by avoiding the size revalidation in preresume unless a shrinking reshape is requested.

Signed-off-by: Heinz Mauelshagen heinzm@redhat.com Signed-off-by: Mike Snitzer snitzer@redhat.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/md/dm-raid.c | 30 ++++++++++++++++++++---------- 1 file changed, 20 insertions(+), 10 deletions(-)

--- a/drivers/md/dm-raid.c +++ b/drivers/md/dm-raid.c @@ -675,15 +675,11 @@ static struct raid_type *get_raid_type_b return NULL; }

-/* - * Conditionally change bdev capacity of @rs - * in case of a disk add/remove reshape - */ -static void rs_set_capacity(struct raid_set *rs) +/* Adjust rdev sectors */ +static void rs_set_rdev_sectors(struct raid_set *rs) { struct mddev *mddev = &rs->md; struct md_rdev *rdev; - struct gendisk *gendisk = dm_disk(dm_table_get_md(rs->ti->table));

/* * raid10 sets rdev->sector to the device size, which @@ -692,8 +688,16 @@ static void rs_set_capacity(struct raid_ rdev_for_each(rdev, mddev) if (!test_bit(Journal, &rdev->flags)) rdev->sectors = mddev->dev_sectors; +}

- set_capacity(gendisk, mddev->array_sectors); +/* + * Change bdev capacity of @rs in case of a disk add/remove reshape + */ +static void rs_set_capacity(struct raid_set *rs) +{ + struct gendisk *gendisk = dm_disk(dm_table_get_md(rs->ti->table)); + + set_capacity(gendisk, rs->md.array_sectors); revalidate_disk(gendisk); }

@@ -1674,8 +1678,11 @@ static void do_table_event(struct work_s struct raid_set *rs = container_of(ws, struct raid_set, md.event_work);

smp_rmb(); /* Make sure we access most actual mddev properties */ - if (!rs_is_reshaping(rs)) + if (!rs_is_reshaping(rs)) { + if (rs_is_raid10(rs)) + rs_set_rdev_sectors(rs); rs_set_capacity(rs); + } dm_table_event(rs->ti->table); }

@@ -3842,11 +3849,10 @@ static int raid_preresume(struct dm_targ mddev->resync_min = mddev->recovery_cp; }

- rs_set_capacity(rs); - /* Check for any reshape request unless new raid set */ if (test_and_clear_bit(RT_FLAG_RESHAPE_RS, &rs->runtime_flags)) { /* Initiate a reshape. */ + rs_set_rdev_sectors(rs); mddev_lock_nointr(mddev); r = rs_start_reshape(rs); mddev_unlock(mddev); @@ -3875,6 +3881,10 @@ static void raid_resume(struct dm_target mddev->ro = 0; mddev->in_sync = 0;

+ /* Only reduce raid set size before running a disk removing reshape. */ + if (mddev->delta_disks < 0) + rs_set_capacity(rs); + /* * Keep the RAID set frozen if reshape/rebuild flags are set. * The RAID set is unfrozen once the next table load/resume,

Patches currently in stable-queue which might be from heinzm@redhat.com are

queue-4.15/dm-raid-fix-raid-set-size-revalidation.patch