ocfs2/hb: Expose the list of heartbeating nodes via debugfs

This patch creates a debugfs file, o2hb/livesnodes, which exposes the
aggregate list of heartbeating node across all heartbeat regions.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
diff --git a/fs/ocfs2/cluster/heartbeat.h b/fs/ocfs2/cluster/heartbeat.h
index e511339..2f16492 100644
--- a/fs/ocfs2/cluster/heartbeat.h
+++ b/fs/ocfs2/cluster/heartbeat.h
@@ -75,7 +75,8 @@
 			      struct o2hb_callback_func *hc);
 void o2hb_fill_node_map(unsigned long *map,
 			unsigned bytes);
-void o2hb_init(void);
+void o2hb_exit(void);
+int o2hb_init(void);
 int o2hb_check_node_heartbeating(u8 node_num);
 int o2hb_check_node_heartbeating_from_callback(u8 node_num);
 int o2hb_check_local_node_heartbeating(void);