Commit a6da4ef8 authored by Goldwyn Rodrigues's avatar Goldwyn Rodrigues Committed by NeilBrown
Browse files

md: re-add a failed disk 



This adds the capability of re-adding a failed disk by
writing "re-add" to /sys/block/mdXX/md/dev-YYY/state.

This facilitates adding disks which have encountered a temporary
error such as a network disconnection/hiccup in an iSCSI device,
or a SAN cable disconnection which has been restored. In such
a situation, you do not need to remove and re-add the device.
Writing re-add to the failed device's state would add it again
to the array and perform the recovery of only the blocks which
were written after the device failed.

This works for generic md, and is not related to clustering. However,
this patch is to ease re-add operations listed above in clustering
environments.

Signed-off-by: default avatarGoldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent 88bcfef7

drivers/md/md.c

+37 −20
Original line number Diff line number Diff line
@@ -2375,6 +2375,36 @@ repeat: 
}

EXPORT_SYMBOL(md_update_sb);



static int add_bound_rdev(struct md_rdev *rdev)

{

	struct mddev *mddev = rdev->mddev;

	int err = 0;



	if (!mddev->pers->hot_remove_disk) {

		/* If there is hot_add_disk but no hot_remove_disk

		 * then added disks for geometry changes,

		 * and should be added immediately.

		 */

		super_types[mddev->major_version].

			validate_super(mddev, rdev);

		err = mddev->pers->hot_add_disk(mddev, rdev);

		if (err) {

			unbind_rdev_from_array(rdev);

			export_rdev(rdev);

			return err;

		}

	}

	sysfs_notify_dirent_safe(rdev->sysfs_state);



	set_bit(MD_CHANGE_DEVS, &mddev->flags);

	if (mddev->degraded)

		set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);

	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);

	md_new_event(mddev);

	md_wakeup_thread(mddev->thread);

	return 0;

}



/* words written to sysfs files may, or may not, be \n terminated.

 * We want to accept with case. For this we use cmd_match.

 */
@@ -2564,6 +2594,12 @@ state_store(struct md_rdev *rdev, const char *buf, size_t len) 
			clear_bit(Replacement, &rdev->flags);

			err = 0;

		}

	} else if (cmd_match(buf, "re-add")) {

		if (test_bit(Faulty, &rdev->flags) && (rdev->raid_disk == -1)) {

			clear_bit(Faulty, &rdev->flags);

			err = add_bound_rdev(rdev);

		} else

			err = -EBUSY;

	}

	if (!err)

		sysfs_notify_dirent_safe(rdev->sysfs_state);
@@ -5875,29 +5911,10 @@ static int add_new_disk(struct mddev *mddev, mdu_disk_info_t *info) 


		rdev->raid_disk = -1;

		err = bind_rdev_to_array(rdev, mddev);

		if (!err && !mddev->pers->hot_remove_disk) {

			/* If there is hot_add_disk but no hot_remove_disk

			 * then added disks for geometry changes,

			 * and should be added immediately.

			 */

			super_types[mddev->major_version].

				validate_super(mddev, rdev);

			err = mddev->pers->hot_add_disk(mddev, rdev);

			if (err)

				unbind_rdev_from_array(rdev);

		}

		if (err)

			export_rdev(rdev);

		else

			sysfs_notify_dirent_safe(rdev->sysfs_state);



		set_bit(MD_CHANGE_DEVS, &mddev->flags);

		if (mddev->degraded)

			set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);

		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);

		if (!err)

			md_new_event(mddev);

		md_wakeup_thread(mddev->thread);

			err = add_bound_rdev(rdev);

		if (mddev_is_clustered(mddev) &&

				(info->state & (1 << MD_DISK_CLUSTER_ADD)))

			md_cluster_ops->add_new_disk_finish(mddev);

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