}
 EXPORT_SYMBOL_GPL(o2hb_setup_callback);
 
-int o2hb_register_callback(struct o2hb_callback_func *hc)
+static struct o2hb_region *o2hb_find_region(const char *region_uuid)
+{
+       struct o2hb_region *p, *reg = NULL;
+
+       assert_spin_locked(&o2hb_live_lock);
+
+       list_for_each_entry(p, &o2hb_all_regions, hr_all_item) {
+               if (!strcmp(region_uuid, config_item_name(&p->hr_item))) {
+                       reg = p;
+                       break;
+               }
+       }
+
+       return reg;
+}
+
+static int o2hb_region_get(const char *region_uuid)
+{
+       int ret = 0;
+       struct o2hb_region *reg;
+
+       spin_lock(&o2hb_live_lock);
+
+       reg = o2hb_find_region(region_uuid);
+       if (!reg)
+               ret = -ENOENT;
+       spin_unlock(&o2hb_live_lock);
+
+       if (!ret)
+               ret = o2nm_depend_item(®->hr_item);
+
+       return ret;
+}
+
+static void o2hb_region_put(const char *region_uuid)
+{
+       struct o2hb_region *reg;
+
+       spin_lock(&o2hb_live_lock);
+
+       reg = o2hb_find_region(region_uuid);
+
+       spin_unlock(&o2hb_live_lock);
+
+       if (reg)
+               o2nm_undepend_item(®->hr_item);
+}
+
+int o2hb_register_callback(const char *region_uuid,
+                          struct o2hb_callback_func *hc)
 {
        struct o2hb_callback_func *tmp;
        struct list_head *iter;
                goto out;
        }
 
+       if (region_uuid) {
+               ret = o2hb_region_get(region_uuid);
+               if (ret)
+                       goto out;
+       }
+
        down_write(&o2hb_callback_sem);
 
        list_for_each(iter, &hbcall->list) {
 }
 EXPORT_SYMBOL_GPL(o2hb_register_callback);
 
-void o2hb_unregister_callback(struct o2hb_callback_func *hc)
+void o2hb_unregister_callback(const char *region_uuid,
+                             struct o2hb_callback_func *hc)
 {
        BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
 
        mlog(ML_HEARTBEAT, "on behalf of %p for funcs %p\n",
             __builtin_return_address(0), hc);
 
+       /* XXX Can this happen _with_ a region reference? */
        if (list_empty(&hc->hc_item))
                return;
 
+       if (region_uuid)
+               o2hb_region_put(region_uuid);
+
        down_write(&o2hb_callback_sem);
 
        list_del_init(&hc->hc_item);
 
                         o2hb_cb_func *func,
                         void *data,
                         int priority);
-int o2hb_register_callback(struct o2hb_callback_func *hc);
-void o2hb_unregister_callback(struct o2hb_callback_func *hc);
+int o2hb_register_callback(const char *region_uuid,
+                          struct o2hb_callback_func *hc);
+void o2hb_unregister_callback(const char *region_uuid,
+                             struct o2hb_callback_func *hc);
 void o2hb_fill_node_map(unsigned long *map,
                        unsigned bytes);
 void o2hb_init(void);
 
        },
 };
 
+int o2nm_depend_item(struct config_item *item)
+{
+       return configfs_depend_item(&o2nm_cluster_group.cs_subsys, item);
+}
+
+void o2nm_undepend_item(struct config_item *item)
+{
+       configfs_undepend_item(&o2nm_cluster_group.cs_subsys, item);
+}
+
 static void __exit exit_o2nm(void)
 {
        if (ocfs2_table_header)
 
 void o2nm_node_get(struct o2nm_node *node);
 void o2nm_node_put(struct o2nm_node *node);
 
+int o2nm_depend_item(struct config_item *item);
+void o2nm_undepend_item(struct config_item *item);
+
 #endif /* O2CLUSTER_NODEMANAGER_H */
 
 
 void o2net_unregister_hb_callbacks(void)
 {
-       o2hb_unregister_callback(&o2net_hb_up);
-       o2hb_unregister_callback(&o2net_hb_down);
+       o2hb_unregister_callback(NULL, &o2net_hb_up);
+       o2hb_unregister_callback(NULL, &o2net_hb_down);
 }
 
 int o2net_register_hb_callbacks(void)
        o2hb_setup_callback(&o2net_hb_up, O2HB_NODE_UP_CB,
                            o2net_hb_node_up_cb, NULL, O2NET_HB_PRI);
 
-       ret = o2hb_register_callback(&o2net_hb_up);
+       ret = o2hb_register_callback(NULL, &o2net_hb_up);
        if (ret == 0)
-               ret = o2hb_register_callback(&o2net_hb_down);
+               ret = o2hb_register_callback(NULL, &o2net_hb_down);
 
        if (ret)
                o2net_unregister_hb_callbacks();
 
 
 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm)
 {
-       o2hb_unregister_callback(&dlm->dlm_hb_up);
-       o2hb_unregister_callback(&dlm->dlm_hb_down);
+       o2hb_unregister_callback(NULL, &dlm->dlm_hb_up);
+       o2hb_unregister_callback(NULL, &dlm->dlm_hb_down);
        o2net_unregister_handler_list(&dlm->dlm_domain_handlers);
 }
 
 
        o2hb_setup_callback(&dlm->dlm_hb_down, O2HB_NODE_DOWN_CB,
                            dlm_hb_node_down_cb, dlm, DLM_HB_NODE_DOWN_PRI);
-       status = o2hb_register_callback(&dlm->dlm_hb_down);
+       status = o2hb_register_callback(NULL, &dlm->dlm_hb_down);
        if (status)
                goto bail;
 
        o2hb_setup_callback(&dlm->dlm_hb_up, O2HB_NODE_UP_CB,
                            dlm_hb_node_up_cb, dlm, DLM_HB_NODE_UP_PRI);
-       status = o2hb_register_callback(&dlm->dlm_hb_up);
+       status = o2hb_register_callback(NULL, &dlm->dlm_hb_up);
        if (status)
                goto bail;
 
 
        if (ocfs2_mount_local(osb))
                return 0;
 
-       status = o2hb_register_callback(&osb->osb_hb_down);
+       status = o2hb_register_callback(osb->uuid_str, &osb->osb_hb_down);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }
 
-       status = o2hb_register_callback(&osb->osb_hb_up);
+       status = o2hb_register_callback(osb->uuid_str, &osb->osb_hb_up);
        if (status < 0) {
                mlog_errno(status);
-               o2hb_unregister_callback(&osb->osb_hb_down);
+               o2hb_unregister_callback(osb->uuid_str, &osb->osb_hb_down);
        }
 
 bail:
        if (ocfs2_mount_local(osb))
                return;
 
-       o2hb_unregister_callback(&osb->osb_hb_down);
-       o2hb_unregister_callback(&osb->osb_hb_up);
+       o2hb_unregister_callback(osb->uuid_str, &osb->osb_hb_down);
+       o2hb_unregister_callback(osb->uuid_str, &osb->osb_hb_up);
 }
 
 void ocfs2_stop_heartbeat(struct ocfs2_super *osb)