ocfs2_dlmfs: Enable the use of user cluster stacks.

Unlike ocfs2, dlmfs has no permanent storage.  It can't store off a
cluster stack it is supposed to be using.  So it can't specify the stack
name in ocfs2_cluster_connect().

Instead, we create ocfs2_cluster_connect_agnostic(), which simply uses
the stack that is currently enabled.  This is find for dlmfs, which will
rely on the stack initialization.

We add the "stackglue" capability to dlmfs's capability list.  This lets
userspace know dlmfs can be used with all cluster stacks.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
diff --git a/fs/ocfs2/stackglue.h b/fs/ocfs2/stackglue.h
index b1981ba..8ce7398 100644
--- a/fs/ocfs2/stackglue.h
+++ b/fs/ocfs2/stackglue.h
@@ -246,6 +246,17 @@
 						   void *recovery_data),
 			  void *recovery_data,
 			  struct ocfs2_cluster_connection **conn);
+/*
+ * Used by callers that don't store their stack name.  They must ensure
+ * all nodes have the same stack.
+ */
+int ocfs2_cluster_connect_agnostic(const char *group,
+				   int grouplen,
+				   struct ocfs2_locking_protocol *lproto,
+				   void (*recovery_handler)(int node_num,
+							    void *recovery_data),
+				   void *recovery_data,
+				   struct ocfs2_cluster_connection **conn);
 int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
 			     int hangup_pending);
 void ocfs2_cluster_hangup(const char *group, int grouplen);