Use bd_claim_by_disk.
Following symlinks are created if md0 is built from sda and sdb
  /sys/block/md0/slaves/sda --> /sys/block/sda
  /sys/block/md0/slaves/sdb --> /sys/block/sdb
  /sys/block/sda/holders/md0 --> /sys/block/md0
  /sys/block/sdb/holders/md0 --> /sys/block/md0
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
        else
                ko = &rdev->bdev->bd_disk->kobj;
        sysfs_create_link(&rdev->kobj, ko, "block");
+       bd_claim_by_disk(rdev->bdev, rdev, mddev->gendisk);
        return 0;
 }
 
                MD_BUG();
                return;
        }
+       bd_release_from_disk(rdev->bdev, rdev->mddev->gendisk);
        list_del_init(&rdev->same_set);
        printk(KERN_INFO "md: unbind<%s>\n", bdevname(rdev->bdev,b));
        rdev->mddev = NULL;