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: Jonathan Brassow <jbrassow@xxxxxxxxxx>
Index: linux-upstream/drivers/md/dm-raid.c
===================================================================
--- linux-upstream.orig/drivers/md/dm-raid.c
+++ linux-upstream/drivers/md/dm-raid.c
@@ -349,6 +349,7 @@ static int validate_region_size(struct r
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(stru
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);
@@ -1389,7 +1421,7 @@ static void raid_resume(struct dm_target
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,
Index: linux-upstream/Documentation/device-mapper/dm-raid.txt
===================================================================
--- linux-upstream.orig/Documentation/device-mapper/dm-raid.txt
+++ linux-upstream/Documentation/device-mapper/dm-raid.txt
@@ -132,3 +132,12 @@ Here we can see the RAID type is raid4,
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
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