FreeBSD/Linux Kernel Cross Reference
sys/fs/union/union.h

     /*      $NetBSD: union.h,v 1.15 2006/05/14 21:31:52 elad Exp $  */
     
     /*
      * Copyright (c) 1994 The Regents of the University of California.
      * 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. 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
     */
    
    /*
     * 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
     */
    
    #ifndef _MISCFS_UNION_H_
    #define _MISCFS_UNION_H_
    
    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
    
    #define UNMNT_BITS "\177\2" \
        "b\00above\0b\01below\0b\02replace\0"
    
    #ifdef _KERNEL
    
    struct union_mount {
            struct vnode    *um_uppervp;
            struct vnode    *um_lowervp;
            kauth_cred_t    um_cred;        /* Credentials of user calling mount */
            int             um_cmode;       /* cmask from mount process */
            int             um_op;          /* Operation mode */
    };
   
   /*
    * DEFDIRMODE is the mode bits used to create a shadow directory.
    */
   #define UN_DIRMODE      (S_IRWXU|S_IRWXG|S_IRWXO)
   #define UN_FILEMODE     (S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH)
   
   /*
    * 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 */
           pid_t                   un_pid;         /* DIAGNOSTIC only */
   };
   
   #define UN_WANTED       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 */
   #define UN_DRAINING     0x20            /* upper node lock is draining */
   #define UN_DRAINED      0x40            /* upper node lock is drained */
   
   extern int union_allocvp(struct vnode **, struct mount *,
                                   struct vnode *, struct vnode *,
                                   struct componentname *, struct vnode *,
                                   struct vnode *, int);
   extern int union_copyfile(struct vnode *, struct vnode *, kauth_cred_t,
       struct lwp *);
   extern int union_copyup(struct union_node *, int, kauth_cred_t,
       struct lwp *);
   extern void union_diruncache(struct union_node *);
   extern int union_dowhiteout(struct union_node *, kauth_cred_t,
       struct lwp *);
   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_vn_create(struct vnode **, struct union_node *,
       struct lwp *);
   extern int union_cn_close(struct vnode *, int, kauth_cred_t,
       struct lwp *);
   extern void union_removed_upper(struct union_node *un);
   extern struct vnode *union_lowervp(struct vnode *);
   extern void union_newlower(struct union_node *, struct vnode *);
   extern void union_newupper(struct union_node *, struct vnode *);
   extern void union_newsize(struct vnode *, off_t, off_t);
   int union_readdirhook(struct vnode **, struct file *, struct lwp *);
   
   #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)(void *);
   
   void union_init(void);
   void union_done(void);
   int union_freevp(struct vnode *);
   
   #ifdef SYSCTL_SETUP_PROTO
   SYSCTL_SETUP_PROTO(sysctl_vfs_union_setup);
   #endif /* SYSCTL_SETUP_PROTO */
   #endif /* _KERNEL */
   #endif /* _MISCFS_UNION_H_ */

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