+extern int union_allocvp __P((struct vnode **, struct mount *,
+ struct vnode *, struct vnode *,
+ struct componentname *, struct vnode *,
+ struct vnode *, int));
+extern int union_copyfile __P((struct vnode *, struct vnode *,
+ struct ucred *, struct proc *));
+extern int union_copyup __P((struct union_node *, int, struct ucred *,
+ struct proc *));
+extern int union_dowhiteout __P((struct union_node *, struct ucred *,
+ struct proc *));
+extern int union_mkshadow __P((struct union_mount *, struct vnode *,
+ struct componentname *, struct vnode **));
+extern int union_mkwhiteout __P((struct union_mount *, struct vnode *,
+ struct componentname *, char *));
+extern int union_vn_create __P((struct vnode **, struct union_node *,
+ struct proc *));
+extern int union_cn_close __P((struct vnode *, int, struct ucred *,
+ struct proc *));
+extern void union_removed_upper __P((struct union_node *un));
+extern struct vnode *union_lowervp __P((struct vnode *));
+extern void union_newlower __P((struct union_node *, struct vnode *));
+extern void union_newupper __P((struct union_node *, struct vnode *));
+extern void union_newsize __P((struct vnode *, off_t, off_t));