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Commit 81f382f9 authored by Jonathan Brassow's avatar Jonathan Brassow Committed by NeilBrown
Browse files

DM RAID: Record and handle missing devices 



Missing dm-raid devices should be recorded in the superblock

When specifying the devices that compose a DM RAID array, it is possible to denote
failed or missing devices with '-'s.  When this occurs, we must record this in the
superblock.  We do this by checking if the array position's data device is missing
and then forcing MD to record the superblock by setting 'MD_CHANGE_DEVS' in
'raid_resume'.  If we do not cause the superblock to be rewritten by the resume
function, it is possible for a stale superblock to be written by an out-going
in-active table (during 'raid_dtr').

Signed-off-by: default avatarJonathan Brassow <jbrassow@redhat.com>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent 47525e59

drivers/md/dm-raid.c

+7 −4
Original line number Diff line number Diff line
@@ -614,16 +614,18 @@ static int read_disk_sb(struct md_rdev *rdev, int size) 


static void super_sync(struct mddev *mddev, struct md_rdev *rdev)

{

	struct md_rdev *r;

	int i;

	uint64_t failed_devices;

	struct dm_raid_superblock *sb;

	struct raid_set *rs = container_of(mddev, struct raid_set, md);



	sb = page_address(rdev->sb_page);

	failed_devices = le64_to_cpu(sb->failed_devices);



	rdev_for_each(r, mddev)

		if ((r->raid_disk >= 0) && test_bit(Faulty, &r->flags))

			failed_devices |= (1ULL << r->raid_disk);

	for (i = 0; i < mddev->raid_disks; i++)

		if (!rs->dev[i].data_dev ||

		    test_bit(Faulty, &(rs->dev[i].rdev.flags)))

			failed_devices |= (1ULL << i);



	memset(sb, 0, sizeof(*sb));
@@ -1249,6 +1251,7 @@ static void raid_resume(struct dm_target *ti) 
{

	struct raid_set *rs = ti->private;



	set_bit(MD_CHANGE_DEVS, &rs->md.flags);

	if (!rs->bitmap_loaded) {

		bitmap_load(&rs->md);

		rs->bitmap_loaded = 1;