+ /* update the family_num to mark a new container
+ * generation, being careful to record the existing
+ * family_num in orig_family_num to clean up after
+ * earlier mdadm versions that neglected to set it.
+ */
+ if (mpb->orig_family_num == 0)
+ mpb->orig_family_num = mpb->family_num;
+ mpb->family_num += super->random;
+