contrib/amd/amd/amfs_inherit.c

   1 /*
   2  * Copyright (c) 1997-1999 Erez Zadok
   3  * Copyright (c) 1989 Jan-Simon Pendry
   4  * Copyright (c) 1989 Imperial College of Science, Technology & Medicine
   5  * Copyright (c) 1989 The Regents of the University of California.
   6  * All rights reserved.
   7  *
   8  * This code is derived from software contributed to Berkeley by
   9  * Jan-Simon Pendry at Imperial College, London.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 3. All advertising materials mentioning features or use of this software
  20  *    must display the following acknowledgment:
  21  *      This product includes software developed by the University of
  22  *      California, Berkeley and its contributors.
  23  * 4. Neither the name of the University nor the names of its contributors
  24  *    may be used to endorse or promote products derived from this software
  25  *    without specific prior written permission.
  26  *
  27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  37  * SUCH DAMAGE.
  38  *
  39  *      %W% (Berkeley) %G%
  40  *
  41  * $Id: amfs_inherit.c,v 1.2 1999/01/10 21:53:41 ezk Exp $
  42  *
  43  */
  44
  45 /*
  46  * Inheritance file system.
  47  */
  48
  49 #ifdef HAVE_CONFIG_H
  50 # include <config.h>
  51 #endif /* HAVE_CONFIG_H */
  52 #include <am_defs.h>
  53 #include <amd.h>
  54
  55 /*
  56  * This implements a filesystem restart.
  57  *
  58  * This is a *gross* hack - it knows far too
  59  * much about the way other parts of the
  60  * system work.  See restart.c too.
  61  */
  62
  63 static char *amfs_inherit_match(am_opts *fo);
  64 static int amfs_inherit_fmount(mntfs *mf);
  65 static int amfs_inherit_fumount(mntfs *mf);
  66 static int amfs_inherit_init(mntfs *mf);
  67 static int amfs_inherit_mount(am_node *mp);
  68
  69
  70 /*
  71  * Ops structure
  72  */
  73 am_ops amfs_inherit_ops =
  74 {
  75   "inherit",
  76   amfs_inherit_match,
  77   amfs_inherit_init,
  78   amfs_inherit_mount,
  79   amfs_inherit_fmount,
  80   amfs_auto_fumount,
  81   amfs_inherit_fumount,
  82   amfs_error_lookuppn,
  83   amfs_error_readdir,
  84   0,                            /* amfs_inherit_readlink */
  85   0,                            /* amfs_inherit_mounted */
  86   0,                            /* amfs_inherit_umounted */
  87   find_amfs_auto_srvr,
  88   FS_DISCARD
  89 };
  90
  91
  92 /*
  93  * This should never be called.
  94  */
  95 static char *
  96 amfs_inherit_match(am_opts *fo)
  97 {
  98   plog(XLOG_FATAL, "amfs_inherit_match called!");
  99   return 0;
 100 }
 101
 102
 103 static int
 104 amfs_inherit_init(mntfs *mf)
 105 {
 106   mntfs *mf_link = (mntfs *) mf->mf_private;
 107
 108   if (mf_link == 0) {
 109     plog(XLOG_ERROR, "Remount collision on %s?", mf->mf_mount);
 110     plog(XLOG_FATAL, "Attempting to init not-a-filesystem");
 111     return EINVAL;
 112   }
 113
 114   if (mf_link->mf_ops->fs_init)
 115     return (*mf_link->mf_ops->fs_init) (mf_link);
 116   return 0;
 117 }
 118
 119
 120 /*
 121  * Take the linked mount point and
 122  * propagate.
 123  */
 124 static mntfs *
 125 amfs_inherit_inherit(mntfs *mf)
 126 {
 127   mntfs *mf_link = (mntfs *) mf->mf_private;
 128
 129   if (mf_link == 0) {
 130     plog(XLOG_FATAL, "Attempting to inherit not-a-filesystem");
 131     return 0;                   /* XXX */
 132   }
 133   mf_link->mf_fo = mf->mf_fo;
 134
 135   /*
 136    * Discard the old map.
 137    * Don't call am_unmounted since this
 138    * node was never really mounted in the
 139    * first place.
 140    */
 141   mf->mf_private = 0;
 142   free_mntfs(mf);
 143
 144   /*
 145    * Free the dangling reference
 146    * to the mount link.
 147    */
 148   free_mntfs(mf_link);
 149
 150   /*
 151    * Get a hold of the other entry
 152    */
 153   mf_link->mf_flags &= ~MFF_RESTART;
 154
 155   /* Say what happened */
 156   plog(XLOG_INFO, "restarting %s on %s", mf_link->mf_info, mf_link->mf_mount);
 157
 158   return mf_link;
 159 }
 160
 161
 162 static int
 163 amfs_inherit_mount(am_node *mp)
 164 {
 165   mntfs *newmf = amfs_inherit_inherit(mp->am_mnt);
 166
 167   if (newmf) {
 168     mp->am_mnt = newmf;
 169     /*
 170      * XXX - must do the am_mounted call here
 171      */
 172     if (newmf->mf_ops->fs_flags & FS_MBACKGROUND)
 173       am_mounted(mp);
 174
 175     new_ttl(mp);
 176     return 0;
 177   }
 178   return EINVAL;
 179 }
 180
 181
 182 static int
 183 amfs_inherit_fmount(mntfs *mf)
 184 {
 185   am_node *mp = find_mf(mf);
 186
 187   if (mp)
 188     return amfs_inherit_mount(mp);
 189   return amfs_inherit_inherit(mf) ? 0 : EINVAL;
 190 }
 191
 192
 193 static int
 194 amfs_inherit_fumount(mntfs *mf)
 195 {
 196   /*
 197    * Always succeed
 198    */
 199   return 0;
 200 }