ocfs2: Depend on configfs heartbeat items.

ocfs2 mounts require a heartbeat region.  Use the new configfs_depend_item()
facility to actually depend on them so they can't go away from under us.

First, teach cluster/nodemanager.c to depend an item on the o2cb subsystem.
Then teach o2hb_register_callbacks to take a UUID and depend on the
appropriate region.  Finally, teach all users of o2hb to pass a UUID or
NULL if they don't require a pin.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/ocfs2/cluster/nodemanager.h b/fs/ocfs2/cluster/nodemanager.h
index 070522138ae2..55ae1a00d735 100644
--- a/fs/ocfs2/cluster/nodemanager.h
+++ b/fs/ocfs2/cluster/nodemanager.h
@@ -77,4 +77,7 @@ struct o2nm_node *o2nm_get_node_by_ip(__be32 addr);
 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 */