md/raid1: If there is a spare and a want_replacement device, start replacement.

When attempting to add a spare to a RAID1 array, also consider
adding it as a replacement for a want_replacement device.

Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 6df0c41578afc4457f8bed383f64450c0cd5bf41..e3cfca7cde16e32c92949d8f2e3cc69d26217cae 100644 (file)
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1315,8 +1315,9 @@ static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
        if (rdev->raid_disk >= 0)
                first = last = rdev->raid_disk;
 
-       for (mirror = first; mirror <= last; mirror++)
-               if ( !(p=conf->mirrors+mirror)->rdev) {
+       for (mirror = first; mirror <= last; mirror++) {
+               p = conf->mirrors+mirror;
+               if (!p->rdev) {
 
                        disk_stack_limits(mddev->gendisk, rdev->bdev,
                                          rdev->data_offset << 9);
@@ -1343,6 +1344,18 @@ static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
                        rcu_assign_pointer(p->rdev, rdev);
                        break;
                }
+               if (test_bit(WantReplacement, &p->rdev->flags) &&
+                   p[conf->raid_disks].rdev == NULL) {
+                       /* Add this device as a replacement */
+                       clear_bit(In_sync, &rdev->flags);
+                       set_bit(Replacement, &rdev->flags);
+                       rdev->raid_disk = mirror;
+                       err = 0;
+                       conf->fullsync = 1;
+                       rcu_assign_pointer(p[conf->raid_disks].rdev, rdev);
+                       break;
+               }
+       }
        md_integrity_add_rdev(rdev, mddev);
        print_conf(conf);
        return err;