DM RAID: Record and handle missing devices (81f382f9) · Commits · 戴 / test

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:

Jonathan Brassow <jbrassow@redhat.com> Signed-off-by:

NeilBrown <neilb@suse.de>

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;

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