Commit d20c4b08 authored Oct 29, 2014 by Heinz Mauelshagen Committed by Mike Snitzer Oct 29, 2014

dm raid: fix inaccessible superblocks causing oops in configure_discard_support

Commit 48cf06bc ("dm raid: add discard support for RAID levels 4, 5
and 6") did not properly handle missing metadata device(s). A failing
read of the superblock causes the metadata and data devices to be
removed from the dev array in struct raid_set, setting references to
both devices to NULL. configure_discard_support() nonetheless tries to
access the data dev unconditionally causing an oops.

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

parent 40d43c4b

drivers/md/dm-raid.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -1172,8 +1172,12 @@ static void configure_discard_support(struct dm_target ti, struct raid_set rs)
		raid456 = (rs->md.level == 4 \|\| rs->md.level == 5 \|\| rs->md.level == 6);

		for (i = 0; i < rs->md.raid_disks; i++) {
		struct request_queue *q = bdev_get_queue(rs->dev[i].rdev.bdev);
		struct request_queue *q;

		if (!rs->dev[i].rdev.bdev)
		continue;

		q = bdev_get_queue(rs->dev[i].rdev.bdev);
		if (!q \|\| !blk_queue_discard(q))
		return;