1 files changed, 30 insertions, 5 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 4edcda8f4869..4869128bf742 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3001,6 +3001,9 @@ level_store(mddev_t *mddev, const char *buf, size_t len)
                 return -EINVAL;
         }
 
+        list_for_each_entry(rdev, &mddev->disks, same_set)
+                rdev->new_raid_disk = rdev->raid_disk;
+
         /* ->takeover must set new_* and/or delta_disks
          * if it succeeds, and may set them when it fails.
          */
@@ -3051,13 +3054,35 @@ level_store(mddev_t *mddev, const char *buf, size_t len)
                 mddev->safemode = 0;
         }
 
-        module_put(mddev->pers->owner);
-        /* Invalidate devices that are now superfluous */
-        list_for_each_entry(rdev, &mddev->disks, same_set)
-                if (rdev->raid_disk >= mddev->raid_disks) {
-                        rdev->raid_disk = -1;
+        list_for_each_entry(rdev, &mddev->disks, same_set) {
+                char nm[20];
+                if (rdev->raid_disk < 0)
+                        continue;
+                if (rdev->new_raid_disk > mddev->raid_disks)
+                        rdev->new_raid_disk = -1;
+                if (rdev->new_raid_disk == rdev->raid_disk)
+                        continue;
+                sprintf(nm, "rd%d", rdev->raid_disk);
+                sysfs_remove_link(&mddev->kobj, nm);
+        }
+        list_for_each_entry(rdev, &mddev->disks, same_set) {
+                if (rdev->raid_disk < 0)
+                        continue;
+                if (rdev->new_raid_disk == rdev->raid_disk)
+                        continue;
+                rdev->raid_disk = rdev->new_raid_disk;
+                if (rdev->raid_disk < 0)
                         clear_bit(In_sync, &rdev->flags);
+                else {
+                        char nm[20];
+                        sprintf(nm, "rd%d", rdev->raid_disk);
+                        if(sysfs_create_link(&mddev->kobj, &rdev->kobj, nm))
+                                printk("md: cannot register %s for %s after level change\n",
+                                       nm, mdname(mddev));
                 }
+        }
+
+        module_put(mddev->pers->owner);
         mddev->pers = pers;
         mddev->private = priv;
         strlcpy(mddev->clevel, pers->name, sizeof(mddev->clevel));