/*
 * Copyright (c) 1994 The Regents of the University of California.
 * Copyright (c) 1994 Jan-Simon Pendry.
 * All rights reserved.
 *
 * This code is derived from software donated to Berkeley by
 * Jan-Simon Pendry.
 *
 * %sccs.include.redist.c%
 *
 *	@(#)union.h	1.1 (Berkeley) 01/28/94
 */

struct union_args {
	char		*target;	/* Target of loopback  */
};

struct union_mount {
	struct vnode	*um_uppervp;
	struct vnode	*um_lowervp;
	struct ucred	*um_cred;	/* Credentials of user calling mount */
};

/* begin XXX */
#define VT_UNION VT_LOFS
/*#define MOUNT_UNION 15*/
/* end XXX */

#ifdef KERNEL

/*
 * DEFDIRMODE is the mode bits used to create a shadow directory.
 */
#define VRWXMODE (VREAD|VWRITE|VEXEC)
#define VRWMODE (VREAD|VWRITE)
#define UN_DIRMODE ((VRWXMODE)|(VRWXMODE>>3)|(VRWXMODE>>6))
#define UN_FILEMODE ((VRWMODE)|(VRWMODE>>3)|(VRWMODE>>6))

/*
 * A cache of vnode references
 */
struct union_node {
	struct union_node	*un_next;	/* Hash chain */
	struct vnode	        *un_uppervp;	/* overlaying object */
	struct vnode	        *un_lowervp;	/* underlying object */
	struct vnode		*un_dirvp;	/* Parent dir of uppervp */
	struct vnode		*un_vnode;	/* Back pointer */
	char			*un_path;	/* saved component name */
	int			un_flags;
	pid_t			un_pid;
};

#define UN_WANT 0x01
#define UN_LOCKED 0x02

extern int union_node_create __P((struct mount *mp, struct vnode *target, struct vnode **vpp));

#define	MOUNTTOUNIONMOUNT(mp) ((struct union_mount *)((mp)->mnt_data))
#define	VTOUNION(vp) ((struct union_node *)(vp)->v_data)
#define	UNIONTOV(un) ((un)->un_vnode)
#define	LOWERVP(vp) (VTOUNION(vp)->un_lowervp)
#define	UPPERVP(vp) (VTOUNION(vp)->un_lowervp)
#define OTHERVP(vp) (UPPERVP(vp) ? UPPERVP(vp) : LOWERVP(vp))

extern int (**union_vnodeop_p)();
extern struct vfsops union_vfsops;
#endif /* KERNEL */