sys/vfs/union/union.h

   1 /*
   2  * Copyright (c) 1994 The Regents of the University of California.
   3  * Copyright (c) 1994 Jan-Simon Pendry.
   4  * All rights reserved.
   5  *
   6  * This code is derived from software donated to Berkeley by
   7  * Jan-Simon Pendry.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. All advertising materials mentioning features or use of this software
  18  *    must display the following acknowledgement:
  19  *      This product includes software developed by the University of
  20  *      California, Berkeley and its contributors.
  21  * 4. Neither the name of the University nor the names of its contributors
  22  *    may be used to endorse or promote products derived from this software
  23  *    without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  35  * SUCH DAMAGE.
  36  *
  37  *      @(#)union.h     8.9 (Berkeley) 12/10/94
  38  * $FreeBSD: src/sys/miscfs/union/union.h,v 1.17 1999/12/29 04:54:48 peter Exp $
  39  * $DragonFly: src/sys/vfs/union/union.h,v 1.9 2006/12/23 00:41:30 swildner Exp $
  40  */
  41
  42 struct union_args {
  43         char            *target;        /* Target of loopback  */
  44         int             mntflags;       /* Options on the mount */
  45 };
  46
  47 #define UNMNT_ABOVE     0x0001          /* Target appears below mount point */
  48 #define UNMNT_BELOW     0x0002          /* Target appears below mount point */
  49 #define UNMNT_REPLACE   0x0003          /* Target replaces mount point */
  50 #define UNMNT_OPMASK    0x0003
  51
  52 struct union_mount {
  53         struct vnode    *um_uppervp;    /* UN_ULOCK holds locking state */
  54         struct vnode    *um_lowervp;    /* Left unlocked */
  55         struct ucred    *um_cred;       /* Credentials of user calling mount */
  56         int             um_cmode;       /* cmask from mount process */
  57         int             um_op;          /* Operation mode */
  58 };
  59
  60 #ifdef _KERNEL
  61
  62 #ifndef DIAGNOSTIC
  63 #define DIAGNOSTIC
  64 #endif
  65
  66 #endif
  67
  68 #if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)
  69
  70 /*
  71  * DEFDIRMODE is the mode bits used to create a shadow directory.
  72  */
  73 #define VRWXMODE (VREAD|VWRITE|VEXEC)
  74 #define VRWMODE (VREAD|VWRITE)
  75 #define UN_DIRMODE ((VRWXMODE)|(VRWXMODE>>3)|(VRWXMODE>>6))
  76 #define UN_FILEMODE ((VRWMODE)|(VRWMODE>>3)|(VRWMODE>>6))
  77
  78 /*
  79  * A cache of vnode references  (hangs off v_data)
  80  */
  81 struct union_node {
  82         LIST_ENTRY(union_node)  un_cache;       /* Hash chain */
  83         struct vnode            *un_vnode;      /* Back pointer */
  84         struct vnode            *un_uppervp;    /* overlaying object */
  85         struct vnode            *un_lowervp;    /* underlying object */
  86         struct vnode            *un_dirvp;      /* Parent dir of uppervp */
  87         struct vnode            *un_pvp;        /* Parent vnode */
  88         char                    *un_path;       /* saved component name */
  89         int                     un_openl;       /* # of opens on lowervp */
  90         int                     un_exclcnt;     /* exclusive count */
  91         unsigned int            un_flags;
  92         struct vnode            **un_dircache;  /* cached union stack */
  93         off_t                   un_uppersz;     /* size of upper object */
  94         off_t                   un_lowersz;     /* size of lower object */
  95 #ifdef DIAGNOSTIC
  96         pid_t                   un_pid;
  97 #endif
  98 };
  99
 100 /*
 101  * XXX UN_ULOCK -       indicates that the uppervp is locked
 102  *
 103  * UN_CACHED -  node is in the union cache
 104  */
 105
 106 /*#define UN_ULOCK      0x04*/  /* Upper node is locked */
 107 #define UN_CACHED       0x10    /* In union cache */
 108
 109 /*
 110  * Hash table locking flags
 111  */
 112
 113 #define UNVP_WANT       0x01
 114 #define UNVP_LOCKED     0x02
 115
 116 #define MOUNTTOUNIONMOUNT(mp) ((struct union_mount *)((mp)->mnt_data))
 117 #define VTOUNION(vp) ((struct union_node *)(vp)->v_data)
 118 #define UNIONTOV(un) ((un)->un_vnode)
 119 #define LOWERVP(vp) (VTOUNION(vp)->un_lowervp)
 120 #define UPPERVP(vp) (VTOUNION(vp)->un_uppervp)
 121 #define OTHERVP(vp) (UPPERVP(vp) ? UPPERVP(vp) : LOWERVP(vp))
 122
 123 #define UDEBUG(x)       if (uniondebug) kprintf x
 124 #define UDEBUG_ENABLED  1
 125
 126 #endif
 127
 128 #ifdef _KERNEL
 129
 130 extern int union_allocvp (struct vnode **, struct mount *,
 131                                 struct vnode *,
 132                                 struct vnode *,
 133                                 struct componentname *, struct vnode *,
 134                                 struct vnode *, int);
 135 extern int union_freevp (struct vnode *);
 136 extern struct vnode *union_dircache (struct vnode *, struct thread *);
 137 extern int union_copyup (struct union_node *, int, struct ucred *,
 138                                 struct thread *);
 139 extern int union_dowhiteout (struct union_node *, struct ucred *,
 140                                         struct thread *);
 141 extern int union_mkshadow (struct union_mount *, struct vnode *,
 142                                 struct componentname *, struct vnode **);
 143 extern int union_mkwhiteout (struct union_mount *, struct vnode *,
 144                                 struct componentname *, char *);
 145 extern int union_cn_close (struct vnode *, int, struct ucred *,
 146                                 struct thread *);
 147 extern void union_removed_upper (struct union_node *un);
 148 extern struct vnode *union_lowervp (struct vnode *);
 149 extern void union_newsize (struct vnode *, off_t, off_t);
 150 extern void union_vm_coherency (struct vnode *, struct uio *, int);
 151
 152 extern int (*union_dircheckp) (struct thread *, struct vnode **,
 153                                  struct file *);
 154
 155 extern struct vfsops union_vfsops;
 156 extern int uniondebug;
 157
 158 #endif /* _KERNEL */