tmpfs_rename_lock_directory
int tmpfs_rename_lock_directory(struct vnode *, struct tmpfs_node *);
error = tmpfs_rename_lock_directory(dvp, dnode);
error = tmpfs_rename_lock_directory(tdnode->tn_vnode, tdnode);
error = tmpfs_rename_lock_directory(a_dvp, a_dnode);
error = tmpfs_rename_lock_directory(b_dvp, b_dnode);