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     8.4 (Berkeley) %G%
 */

struct union_args {
        char            *target;        /* Target of loopback  */
        int             mntflags;       /* Options on the mount */
};

#define UNMNT_ABOVE     0x0001          /* Target appears below mount point */
#define UNMNT_BELOW     0x0002          /* Target appears below mount point */
#define UNMNT_REPLACE   0x0003          /* Target replaces mount point */
#define UNMNT_OPMASK    0x0003

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 */
        int             um_op;          /* Operation mode */
};

#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 {
        LIST_ENTRY(union_node)  un_cache;       /* 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 */
        unsigned int            un_flags;
        off_t                   un_uppersz;     /* size of upper object */
        off_t                   un_lowersz;     /* size of lower object */
#ifdef DIAGNOSTIC
        pid_t                   un_pid;
#endif
};

#define UN_WANT         0x01
#define UN_LOCKED       0x02
#define UN_ULOCK        0x04            /* Upper node is locked */
#define UN_KLOCK        0x08            /* Keep upper node locked on vput */
#define UN_CACHED       0x10            /* In union cache */

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 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));

#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 */