Commit 4ec1e369 authored by Jonathan Brassow's avatar Jonathan Brassow Committed by NeilBrown
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DM RAID: Add rebuild capability for RAID10 



DM RAID:  Add code to validate replacement slots for RAID10 arrays

RAID10 can handle 'copies - 1' failures for each mirror group.  This code
ensures the user has provided a valid array - one whose devices specified for
rebuild do not exceed the amount of redundancy available.

Signed-off-by: default avatarJonathan Brassow <jbrassow@redhat.com>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent eb649123

Documentation/device-mapper/dm-raid.txt

+9 −0
Original line number Diff line number Diff line
@@ -132,3 +132,12 @@ Here we can see the RAID type is raid4, there are 5 devices - all of 
which are 'A'live, and the array is 2/490221568 complete with recovery.

Faulty or missing devices are marked 'D'.  Devices that are out-of-sync

are marked 'a'.





Version History

---------------

1.0.0	Initial version.  Support for RAID 4/5/6

1.1.0	Added support for RAID 1

1.2.0	Handle creation of arrays that contain failed devices.

1.3.0	Added support for RAID 10

1.3.1	Allow device replacement/rebuild for RAID 10

drivers/md/dm-raid.c

+33 −1
Original line number Diff line number Diff line
@@ -349,6 +349,7 @@ static int validate_region_size(struct raid_set *rs, unsigned long region_size) 
static int validate_rebuild_devices(struct raid_set *rs)

{

	unsigned i, rebuild_cnt = 0;

	unsigned rebuilds_per_group, copies, d;



	if (!(rs->print_flags & DMPF_REBUILD))

		return 0;
@@ -369,6 +370,37 @@ static int validate_rebuild_devices(struct raid_set *rs) 
			goto too_many;

		break;

	case 10:

		copies = raid10_md_layout_to_copies(rs->md.layout);

		if (rebuild_cnt < copies)

			break;



		/*

		 * It is possible to have a higher rebuild count for RAID10,

		 * as long as the failed devices occur in different mirror

		 * groups (i.e. different stripes).

		 *

		 * Right now, we only allow for "near" copies.  When other

		 * formats are added, we will have to check those too.

		 *

		 * When checking "near" format, make sure no adjacent devices

		 * have failed beyond what can be handled.  In addition to the

		 * simple case where the number of devices is a multiple of the

		 * number of copies, we must also handle cases where the number

		 * of devices is not a multiple of the number of copies.

		 * E.g.    dev1 dev2 dev3 dev4 dev5

		 *          A    A    B    B    C

		 *          C    D    D    E    E

		 */

		rebuilds_per_group = 0;

		for (i = 0; i < rs->md.raid_disks * copies; i++) {

			d = i % rs->md.raid_disks;

			if (!test_bit(In_sync, &rs->dev[d].rdev.flags) &&

			    (++rebuilds_per_group >= copies))

				goto too_many;

			if (!((i + 1) % copies))

				rebuilds_per_group = 0;

		}

		break;

	default:

		DMERR("The rebuild parameter is not supported for %s",

		      rs->raid_type->name);
@@ -1385,7 +1417,7 @@ static void raid_resume(struct dm_target *ti) 


static struct target_type raid_target = {

	.name = "raid",

	.version = {1, 3, 0},

	.version = {1, 3, 1},

	.module = THIS_MODULE,

	.ctr = raid_ctr,

	.dtr = raid_dtr,

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