ocfs2: Introduce the new ocfs2_cluster_connect/disconnect() API.

This step introduces a cluster stack agnostic API for initializing and
exiting.  fs/ocfs2/dlmglue.c no longer uses o2cb/o2dlm knowledge to
connect to the stack.  It is all handled in stackglue.c.

heartbeat.c no longer needs to know how it gets called.
ocfs2_do_node_down() is now a clean recovery trigger.

The big gotcha is the ordering of initializations and de-initializations done
underneath ocfs2_cluster_connect().  ocfs2_dlm_init() used to do all
o2dlm initialization in one block.  Thus, the o2dlm functionality of
ocfs2_cluster_connect() is very straightforward.  ocfs2_dlm_shutdown(),
however, did a few things between de-registration of the eviction
callback and actually shutting down the domain.  Now de-registration and
shutdown of the domain are wrapped within the single
ocfs2_cluster_disconnect() call.  I've checked the code paths to make
sure we can safely tear down things in ocfs2_dlm_shutdown() before
calling ocfs2_cluster_disconnect().  The filesystem has already set
itself to ignore the callback.

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

fs/ocfs2/super.c

@@ -1251,9 +1251,9 @@ static void ocfs2_dismount_volume(struct super_block *sb, int mnt_err)
 
 	ocfs2_sync_blockdev(sb);
 
-	/* No dlm means we've failed during mount, so skip all the
-	 * steps which depended on that to complete. */
-	if (osb->dlm) {
+	/* No cluster connection means we've failed during mount, so skip
+	 * all the steps which depended on that to complete. */
+	if (osb->cconn) {
 		tmp = ocfs2_super_lock(osb, 1);
 		if (tmp < 0) {
 			mlog_errno(tmp);
@@ -1264,12 +1264,12 @@ static void ocfs2_dismount_volume(struct super_block *sb, int mnt_err)
 	if (osb->slot_num != OCFS2_INVALID_SLOT)
 		ocfs2_put_slot(osb);
 
-	if (osb->dlm)
+	if (osb->cconn)
 		ocfs2_super_unlock(osb, 1);
 
 	ocfs2_release_system_inodes(osb);
 
-	if (osb->dlm)
+	if (osb->cconn)
 		ocfs2_dlm_shutdown(osb);
 
 	debugfs_remove(osb->osb_debug_root);
@@ -1341,7 +1341,6 @@ static int ocfs2_initialize_super(struct super_block *sb,
 	sb->s_fs_info = osb;
 	sb->s_op = &ocfs2_sops;
 	sb->s_export_op = &ocfs2_export_ops;
-	osb->osb_locking_proto = ocfs2_locking_protocol;
 	sb->s_time_gran = 1;
 	sb->s_flags |= MS_NOATIME;
 	/* this is needed to support O_LARGEFILE */
@@ -1391,8 +1390,6 @@ static int ocfs2_initialize_super(struct super_block *sb,
 	osb->local_alloc_state = OCFS2_LA_UNUSED;
 	osb->local_alloc_bh = NULL;
 
-	ocfs2_setup_hb_callbacks(osb);
-
 	init_waitqueue_head(&osb->osb_mount_event);
 
 	osb->vol_label = kmalloc(OCFS2_MAX_VOL_LABEL_LEN, GFP_KERNEL);