md/raid5: If there is a spare and a want_replacement device, start replacement.
When attempting to add a spare to a RAID[456] array, also consider
adding it as a replacement for a want_replacement device.
This requires that common md code attempt hot_add even when the array
is not formally degraded.
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index c80f8c2..b2c8385 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -5376,8 +5376,9 @@
disk = rdev->saved_raid_disk;
else
disk = first;
- for ( ; disk <= last ; disk++)
- if ((p=conf->disks + disk)->rdev == NULL) {
+ for ( ; disk <= last ; disk++) {
+ p = conf->disks + disk;
+ if (p->rdev == NULL) {
clear_bit(In_sync, &rdev->flags);
rdev->raid_disk = disk;
err = 0;
@@ -5386,6 +5387,17 @@
rcu_assign_pointer(p->rdev, rdev);
break;
}
+ if (test_bit(WantReplacement, &p->rdev->flags) &&
+ p->replacement == NULL) {
+ clear_bit(In_sync, &rdev->flags);
+ set_bit(Replacement, &rdev->flags);
+ rdev->raid_disk = disk;
+ err = 0;
+ conf->fullsync = 1;
+ rcu_assign_pointer(p->replacement, rdev);
+ break;
+ }
+ }
print_raid5_conf(conf);
return err;
}