ocfs2: Add support for heartbeat=global mount option

Adds support for heartbeat=global mount option. It ensures that the heartbeat
mode passed matches the one enabled on disk.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>

fs/ocfs2/ocfs2_fs.h

@@ -376,6 +376,7 @@ static struct ocfs2_system_inode_info ocfs2_system_inodes[NUM_SYSTEM_INODES] = {
 /* Parameter passed from mount.ocfs2 to module */
 #define OCFS2_HB_NONE			"heartbeat=none"
 #define OCFS2_HB_LOCAL			"heartbeat=local"
+#define OCFS2_HB_GLOBAL			"heartbeat=global"
 
 /*
  * OCFS2 directory file types.  Only the low 3 bits are used.  The