FreeBSD/Linux Kernel Cross Reference
sys/fs/unionfs/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.
     * 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: releng/6.1/sys/fs/unionfs/union.h 139776 2005-01-06 18:10:42Z imp $
     */
    
    #define UNMNT_ABOVE     0x0001          /* Target appears above mount point */
    #define UNMNT_BELOW     0x0002          /* Target appears below mount point */
    #define UNMNT_REPLACE   0x0003          /* Target replaces mount point */
    
    struct union_mount {
            struct vnode    *um_uppervp;    /* UN_ULOCK holds locking state */
            struct vnode    *um_lowervp;    /* Left unlocked */
            struct ucred    *um_cred;       /* Credentials of user calling mount */
            int             um_cmode;       /* cmask from mount process */
            int             um_op;          /* Operation mode */
            dev_t           um_upperdev;    /* Upper root node fsid[0]*/
    };
    
    #ifdef _KERNEL
    
    #ifndef DIAGNOSTIC
    #define DIAGNOSTIC
    #endif
    
    /*
     * 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  (hangs off v_data)
     */
    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_openl;       /* # of opens on lowervp */
            int                     un_exclcnt;     /* exclusive count */
            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
    };
    
    /*
     * XXX UN_ULOCK -       indicates that the uppervp is locked
     *
     * UN_CACHED -  node is in the union cache
     */
    
    /*#define UN_ULOCK      0x04*/  /* Upper node is locked */
    #define UN_CACHED       0x10    /* In union cache */
    
    /*
     * Hash table locking flags
     */
    
    #define UNVP_WANT       0x01
   #define UNVP_LOCKED     0x02
   
   extern int union_allocvp(struct vnode **, struct mount *,
                                   struct vnode *, 
                                   struct vnode *, 
                                   struct componentname *, struct vnode *,
                                   struct vnode *, int);
   extern int union_freevp(struct vnode *);
   extern struct vnode *union_dircache_get(struct vnode *, struct thread *);
   extern void union_dircache_free(struct union_node *);
   extern int union_copyup(struct union_node *, int, struct ucred *,
                                   struct thread *);
   extern int union_dowhiteout(struct union_node *, struct ucred *,
                                           struct thread *);
   extern int union_mkshadow(struct union_mount *, struct vnode *,
                                   struct componentname *, struct vnode **);
   extern int union_mkwhiteout(struct union_mount *, struct vnode *,
                                   struct componentname *, char *);
   extern int union_cn_close(struct vnode *, int, struct ucred *,
                                   struct thread *);
   extern void union_removed_upper(struct union_node *un);
   extern struct vnode *union_lowervp(struct vnode *);
   extern void union_newsize(struct vnode *, off_t, off_t);
   
   extern int (*union_dircheckp)(struct thread *, 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))
   
   #define UDEBUG(x)       if (uniondebug) printf x
   #define UDEBUG_ENABLED  1
   
   extern struct vop_vector union_vnodeops;
   extern struct vfsops union_vfsops;
   extern int uniondebug;
   
   #endif /* _KERNEL */

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