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[unix-history] / usr / src / sys / miscfs / union / union.h

/*
* 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     1.2 (Berkeley) %G%
*/

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 */