FreeBSD/Linux Kernel Cross Reference
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.
      *
      * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *      This product includes software developed by the University of
     *      California, Berkeley and its contributors.
     * 4. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     *      @(#)union.h     8.9 (Berkeley) 12/10/94
     * $FreeBSD$
     */
    
    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 */
            struct vnode            *un_pvp;        /* Parent vnode */
            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;
            struct vnode            **un_dircache;  /* cached union stack */
            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 *, int));
   extern int union_freevp __P((struct vnode *));
   extern struct vnode *union_dircache __P((struct vnode *, 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_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_newsize __P((struct vnode *, off_t, off_t));
   
   extern int (*union_dircheckp) __P((struct proc *, struct vnode **,
                                    struct file *));
   
   #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 vop_t **union_vnodeop_p;
   extern struct vfsops union_vfsops;
   #endif /* KERNEL */

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