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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     1.7 (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 */
       int             um_cmode;       /* cmask from mount process */
};

#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_vnode;      /* Back pointer */
       struct vnode            *un_uppervp;    /* overlaying object */
       struct vnode            *un_lowervp;    /* underlying object */
       struct vnode            *un_dirvp;      /* Parent dir of uppervp */
       char                    *un_path;       /* saved component name */
       int                     un_hash;        /* saved un_path hash value */
       int                     un_openl;       /* # of opens on lowervp */
       int                     un_flags;
#ifdef DIAGNOSTIC
       pid_t                   un_pid;
#endif
};

#define UN_WANT 0x01
#define UN_LOCKED 0x02

extern int union_allocvp __P((struct vnode **, struct mount *,
                               struct vnode *, struct vnode *,
                               struct componentname *, struct vnode *,
                               struct vnode *));
extern int union_copyfile __P((struct proc *, struct ucred *,
                               struct vnode *, struct vnode *));
extern int union_mkshadow __P((struct union_mount *, struct vnode *,
                               struct componentname *, struct vnode **));
extern int union_vn_create __P((struct vnode **, struct union_node *,
                               struct proc *));
extern void union_removed_upper __P((struct union_node *un));

#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_uppervp)
#define OTHERVP(vp) (UPPERVP(vp) ? UPPERVP(vp) : LOWERVP(vp))

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