external/bsd/am-utils/dist/amd/amfs_toplvl.c

   1 /*      $NetBSD$        */
   2
   3 /*
   4  * Copyright (c) 1997-2009 Erez Zadok
   5  * Copyright (c) 1990 Jan-Simon Pendry
   6  * Copyright (c) 1990 Imperial College of Science, Technology & Medicine
   7  * Copyright (c) 1990 The Regents of the University of California.
   8  * All rights reserved.
   9  *
  10  * This code is derived from software contributed to Berkeley by
  11  * Jan-Simon Pendry at Imperial College, London.
  12  *
  13  * Redistribution and use in source and binary forms, with or without
  14  * modification, are permitted provided that the following conditions
  15  * are met:
  16  * 1. Redistributions of source code must retain the above copyright
  17  *    notice, this list of conditions and the following disclaimer.
  18  * 2. Redistributions in binary form must reproduce the above copyright
  19  *    notice, this list of conditions and the following disclaimer in the
  20  *    documentation and/or other materials provided with the distribution.
  21  * 3. All advertising materials mentioning features or use of this software
  22  *    must display the following acknowledgment:
  23  *      This product includes software developed by the University of
  24  *      California, Berkeley and its contributors.
  25  * 4. Neither the name of the University nor the names of its contributors
  26  *    may be used to endorse or promote products derived from this software
  27  *    without specific prior written permission.
  28  *
  29  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  30  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  31  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  32  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  33  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  34  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  35  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  37  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  38  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  39  * SUCH DAMAGE.
  40  *
  41  *
  42  * File: am-utils/amd/amfs_toplvl.c
  43  *
  44  */
  45
  46 /*
  47  * Top-level file system
  48  */
  49
  50 #ifdef HAVE_CONFIG_H
  51 # include <config.h>
  52 #endif /* HAVE_CONFIG_H */
  53 #include <am_defs.h>
  54 #include <amd.h>
  55
  56 /****************************************************************************
  57  *** FORWARD DEFINITIONS                                                  ***
  58  ****************************************************************************/
  59 static int amfs_toplvl_init(mntfs *mf);
  60
  61 /****************************************************************************
  62  *** OPS STRUCTURES                                                       ***
  63  ****************************************************************************/
  64 am_ops amfs_toplvl_ops =
  65 {
  66   "toplvl",
  67   amfs_generic_match,
  68   amfs_toplvl_init,             /* amfs_toplvl_init */
  69   amfs_toplvl_mount,
  70   amfs_toplvl_umount,
  71   amfs_generic_lookup_child,
  72   amfs_generic_mount_child,
  73   amfs_generic_readdir,
  74   0,                            /* amfs_toplvl_readlink */
  75   amfs_generic_mounted,
  76   0,                            /* amfs_toplvl_umounted */
  77   amfs_generic_find_srvr,
  78   0,                            /* amfs_toplvl_get_wchan */
  79   FS_MKMNT | FS_NOTIMEOUT | FS_BACKGROUND |
  80           FS_AMQINFO | FS_DIRECTORY, /* nfs_fs_flags */
  81 #ifdef HAVE_FS_AUTOFS
  82   AUTOFS_TOPLVL_FS_FLAGS,
  83 #endif /* HAVE_FS_AUTOFS */
  84 };
  85
  86
  87 /****************************************************************************
  88  *** FUNCTIONS                                                             ***
  89  ****************************************************************************/
  90
  91 static void
  92 set_auto_attrcache_timeout(char *preopts, char *opts, size_t l)
  93 {
  94
  95 #ifdef MNTTAB_OPT_NOAC
  96   /*
  97    * Don't cache attributes - they are changing under the kernel's feet.
  98    * For example, IRIX5.2 will dispense with nfs lookup calls and hand stale
  99    * filehandles to getattr unless we disable attribute caching on the
 100    * automount points.
 101    */
 102   if (gopt.auto_attrcache == 0) {
 103     xsnprintf(preopts, l, ",%s", MNTTAB_OPT_NOAC);
 104     xstrlcat(opts, preopts, l);
 105   }
 106 #endif /* MNTTAB_OPT_NOAC */
 107
 108   /*
 109    * XXX: note that setting these to 0 in the past resulted in an error on
 110    * some systems, which is why it's better to use "noac" if possible.  For
 111    * now, we're setting everything possible, but if this will cause trouble,
 112    * then we'll have to condition the remainder of this on OPT_NOAC.
 113    */
 114 #ifdef MNTTAB_OPT_ACTIMEO
 115   xsnprintf(preopts, l, ",%s=%d", MNTTAB_OPT_ACTIMEO, gopt.auto_attrcache);
 116   xstrlcat(opts, preopts, l);
 117 #else /* MNTTAB_OPT_ACTIMEO */
 118 # ifdef MNTTAB_OPT_ACDIRMIN
 119   xsnprintf(preopts, l, ",%s=%d", MNTTAB_OPT_ACTDIRMIN, gopt.auto_attrcache);
 120   xstrlcat(opts, preopts, l);
 121 # endif /* MNTTAB_OPT_ACDIRMIN */
 122 # ifdef MNTTAB_OPT_ACDIRMAX
 123   xsnprintf(preopts, l, ",%s=%d", MNTTAB_OPT_ACTDIRMAX, gopt.auto_attrcache);
 124   xstrlcat(opts, preopts, l);
 125 # endif /* MNTTAB_OPT_ACDIRMAX */
 126 # ifdef MNTTAB_OPT_ACREGMIN
 127   xsnprintf(preopts, l, ",%s=%d", MNTTAB_OPT_ACTREGMIN, gopt.auto_attrcache);
 128   xstrlcat(opts, preopts, l);
 129 # endif /* MNTTAB_OPT_ACREGMIN */
 130 # ifdef MNTTAB_OPT_ACREGMAX
 131   xsnprintf(preopts, l, ",%s=%d", MNTTAB_OPT_ACTREGMAX, gopt.auto_attrcache);
 132   xstrlcat(opts, preopts, l);
 133 # endif /* MNTTAB_OPT_ACREGMAX */
 134 #endif /* MNTTAB_OPT_ACTIMEO */
 135 }
 136
 137
 138 /*
 139  * Initialize a top-level mount.  In our case, if the user asked for
 140  * forced_unmounts, and the OS supports it, then we try forced/lazy unmounts
 141  * on any previous toplvl mounts.  This is useful if a previous Amd died and
 142  * left behind toplvl mount points (this Amd will clean them up).
 143  *
 144  * WARNING: Don't use forced/lazy unmounts if you have another valid Amd
 145  * running, because this code WILL force those valid toplvl mount points to
 146  * be detached as well!
 147  */
 148 static int
 149 amfs_toplvl_init(mntfs *mf)
 150 {
 151   int error = 0;
 152
 153 #if (defined(MNT2_GEN_OPT_FORCE) || defined(MNT2_GEN_OPT_DETACH)) && (defined(HAVE_UVMOUNT) || defined(HAVE_UMOUNT2))
 154   if (gopt.flags & CFM_FORCED_UNMOUNTS) {
 155     plog(XLOG_INFO, "amfs_toplvl_init: trying forced/lazy unmount of %s",
 156          mf->mf_mount);
 157     error = umount2_fs(mf->mf_mount, AMU_UMOUNT_FORCE | AMU_UMOUNT_DETACH);
 158     if (error)
 159       plog(XLOG_INFO, "amfs_toplvl_init: forced/lazy unmount failed: %m");
 160     else
 161       dlog("amfs_toplvl_init: forced/lazy unmount succeeded");
 162   }
 163 #endif /* (MNT2_GEN_OPT_FORCE || MNT2_GEN_OPT_DETACH) && (HAVE_UVMOUNT || HAVE_UMOUNT2) */
 164   return error;
 165 }
 166
 167
 168 /*
 169  * Mount the top-level
 170  */
 171 int
 172 amfs_toplvl_mount(am_node *mp, mntfs *mf)
 173 {
 174   struct stat stb;
 175   char opts[SIZEOF_OPTS], preopts[SIZEOF_OPTS], toplvl_opts[40];
 176   int error;
 177
 178   /*
 179    * Mounting the automounter.
 180    * Make sure the mount directory exists, construct
 181    * the mount options and call the mount_amfs_toplvl routine.
 182    */
 183
 184   if (stat(mp->am_path, &stb) < 0) {
 185     return errno;
 186   } else if ((stb.st_mode & S_IFMT) != S_IFDIR) {
 187     plog(XLOG_WARNING, "%s is not a directory", mp->am_path);
 188     return ENOTDIR;
 189   }
 190
 191   /*
 192    * Construct some mount options:
 193    *
 194    * Tack on magic map=<mapname> option in mtab to emulate
 195    * SunOS automounter behavior.
 196    */
 197
 198 #ifdef HAVE_FS_AUTOFS
 199   if (mf->mf_flags & MFF_IS_AUTOFS) {
 200     autofs_get_opts(opts, sizeof(opts), mp->am_autofs_fh);
 201   } else
 202 #endif /* HAVE_FS_AUTOFS */
 203   {
 204     preopts[0] = '\0';
 205 #ifdef MNTTAB_OPT_INTR
 206     xstrlcat(preopts, MNTTAB_OPT_INTR, sizeof(preopts));
 207     xstrlcat(preopts, ",", sizeof(preopts));
 208 #endif /* MNTTAB_OPT_INTR */
 209 #ifdef MNTTAB_OPT_IGNORE
 210     xstrlcat(preopts, MNTTAB_OPT_IGNORE, sizeof(preopts));
 211     xstrlcat(preopts, ",", sizeof(preopts));
 212 #endif /* MNTTAB_OPT_IGNORE */
 213     /* write most of the initial options + preopts */
 214     xsnprintf(opts, sizeof(opts), "%s%s,%s=%d,%s,map=%s",
 215               preopts,
 216               MNTTAB_OPT_RW,
 217               MNTTAB_OPT_PORT, nfs_port,
 218               mf->mf_ops->fs_type, mf->mf_info);
 219
 220     /* process toplvl timeo/retrans options, if any */
 221     if (gopt.amfs_auto_timeo[AMU_TYPE_TOPLVL] > 0) {
 222       xsnprintf(toplvl_opts, sizeof(toplvl_opts), ",%s=%d",
 223                 MNTTAB_OPT_TIMEO, gopt.amfs_auto_timeo[AMU_TYPE_TOPLVL]);
 224       xstrlcat(opts, toplvl_opts, sizeof(opts));
 225     }
 226     if (gopt.amfs_auto_retrans[AMU_TYPE_TOPLVL] > 0) {
 227       xsnprintf(toplvl_opts, sizeof(toplvl_opts), ",%s=%d",
 228                 MNTTAB_OPT_RETRANS, gopt.amfs_auto_retrans[AMU_TYPE_TOPLVL]);
 229       xstrlcat(opts, toplvl_opts, sizeof(opts));
 230     }
 231
 232 #ifdef MNTTAB_OPT_NOLOCK
 233     xstrlcat(opts, ",", sizeof(opts));
 234     xstrlcat(opts, MNTTAB_OPT_NOLOCK, sizeof(opts));
 235 #endif /* MNTTAB_OPT_NOLOCK */
 236
 237 #ifdef MNTTAB_OPT_NOAC
 238     if (gopt.auto_attrcache == 0) {
 239       xstrlcat(opts, ",", sizeof(opts));
 240       xstrlcat(opts, MNTTAB_OPT_NOAC, sizeof(opts));
 241     } else
 242 #endif /* MNTTAB_OPT_NOAC */
 243       set_auto_attrcache_timeout(preopts, opts, sizeof(preopts));
 244   }
 245
 246   /* now do the mount */
 247   error = amfs_mount(mp, mf, opts);
 248   if (error) {
 249     errno = error;
 250     plog(XLOG_FATAL, "amfs_toplvl_mount: amfs_mount failed: %m");
 251     return error;
 252   }
 253   return 0;
 254 }
 255
 256
 257 /*
 258  * Unmount a top-level automount node
 259  */
 260 int
 261 amfs_toplvl_umount(am_node *mp, mntfs *mf)
 262 {
 263   struct stat stb;
 264   int unmount_flags = (mf->mf_flags & MFF_ON_AUTOFS) ? AMU_UMOUNT_AUTOFS : 0;
 265   int error;
 266   int count = 0;                /* how many times did we try to unmount? */
 267
 268 again:
 269   /*
 270    * The lstat is needed if this mount is type=direct.
 271    * When that happens, the kernel cache gets confused
 272    * between the underlying type (dir) and the mounted
 273    * type (link) and so needs to be re-synced before
 274    * the unmount.  This is all because the unmount system
 275    * call follows links and so can't actually unmount
 276    * a link (stupid!).  It was noted that doing an ls -ld
 277    * of the mount point to see why things were not working
 278    * actually fixed the problem - so simulate an ls -ld here.
 279    */
 280   if (lstat(mp->am_path, &stb) < 0) {
 281     error = errno;
 282     dlog("lstat(%s): %m", mp->am_path);
 283     goto out;
 284   }
 285   if ((stb.st_mode & S_IFMT) != S_IFDIR) {
 286     plog(XLOG_ERROR, "amfs_toplvl_umount: %s is not a directory, aborting.", mp->am_path);
 287     error = ENOTDIR;
 288     goto out;
 289   }
 290
 291   error = UMOUNT_FS(mp->am_path, mnttab_file_name, unmount_flags);
 292   if (error == EBUSY) {
 293 #ifdef HAVE_FS_AUTOFS
 294     /*
 295      * autofs mounts are "in place", so it is possible
 296      * that we can't just unmount our mount points and go away.
 297      * If that's the case, just give up.
 298      */
 299     if (mf->mf_flags & MFF_IS_AUTOFS)
 300       return error;
 301 #endif /* HAVE_FS_AUTOFS */
 302     plog(XLOG_WARNING, "amfs_toplvl_unmount retrying %s in 1s", mp->am_path);
 303     count++;
 304     sleep(1);
 305     /*
 306      * If user wants forced/lazy unmount semantics, then set those flags,
 307      * but only after we've tried normal lstat/umount a few times --
 308      * otherwise forced unmounts may hang this very same Amd (by preventing
 309      * it from achieving a clean unmount).
 310      */
 311     if (gopt.flags & CFM_FORCED_UNMOUNTS) {
 312       if (count == 5) {         /* after 5 seconds, try MNT_FORCE */
 313         dlog("enabling forced unmounts for toplvl node %s", mp->am_path);
 314         unmount_flags |= AMU_UMOUNT_FORCE;
 315       }
 316       if (count == 10) {        /* after 10 seconds, try MNT_DETACH */
 317         dlog("enabling detached unmounts for toplvl node %s", mp->am_path);
 318         unmount_flags |= AMU_UMOUNT_DETACH;
 319       }
 320     }
 321     goto again;
 322   }
 323 out:
 324   return error;
 325 }