1 /* $NetBSD: amfs_toplvl.c,v 1.1.1.3 2015/01/17 16:34:15 christos Exp $ */
2
3 /*
4 * Copyright (c) 1997-2014 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. 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 *
38 * File: am-utils/amd/amfs_toplvl.c
39 *
40 */
41
42 /*
43 * Top-level file system
44 */
45
46 #ifdef HAVE_CONFIG_H
47 # include <config.h>
48 #endif /* HAVE_CONFIG_H */
49 #include <am_defs.h>
50 #include <amd.h>
51
52 /****************************************************************************
53 *** FORWARD DEFINITIONS ***
54 ****************************************************************************/
55 static int amfs_toplvl_init(mntfs *mf);
56
57 /****************************************************************************
58 *** OPS STRUCTURES ***
59 ****************************************************************************/
60 am_ops amfs_toplvl_ops =
61 {
62 "toplvl",
63 amfs_generic_match,
64 amfs_toplvl_init, /* amfs_toplvl_init */
65 amfs_toplvl_mount,
66 amfs_toplvl_umount,
67 amfs_generic_lookup_child,
68 amfs_generic_mount_child,
69 amfs_generic_readdir,
70 0, /* amfs_toplvl_readlink */
71 amfs_generic_mounted,
72 0, /* amfs_toplvl_umounted */
73 amfs_generic_find_srvr,
74 0, /* amfs_toplvl_get_wchan */
75 FS_MKMNT | FS_NOTIMEOUT | FS_BACKGROUND |
76 FS_AMQINFO | FS_DIRECTORY, /* nfs_fs_flags */
77 #ifdef HAVE_FS_AUTOFS
78 AUTOFS_TOPLVL_FS_FLAGS,
79 #endif /* HAVE_FS_AUTOFS */
80 };
81
82
83 /****************************************************************************
84 *** FUNCTIONS ***
85 ****************************************************************************/
86
87 static void
set_auto_attrcache_timeout(char * preopts,char * opts,size_t l)88 set_auto_attrcache_timeout(char *preopts, char *opts, size_t l)
89 {
90
91 #ifdef MNTTAB_OPT_NOAC
92 /*
93 * Don't cache attributes - they are changing under the kernel's feet.
94 * For example, IRIX5.2 will dispense with nfs lookup calls and hand stale
95 * filehandles to getattr unless we disable attribute caching on the
96 * automount points.
97 */
98 if (gopt.auto_attrcache == 0) {
99 xsnprintf(preopts, l, ",%s", MNTTAB_OPT_NOAC);
100 xstrlcat(opts, preopts, l);
101 }
102 #endif /* MNTTAB_OPT_NOAC */
103
104 /*
105 * XXX: note that setting these to 0 in the past resulted in an error on
106 * some systems, which is why it's better to use "noac" if possible. For
107 * now, we're setting everything possible, but if this will cause trouble,
108 * then we'll have to condition the remainder of this on OPT_NOAC.
109 */
110 #ifdef MNTTAB_OPT_ACTIMEO
111 xsnprintf(preopts, l, ",%s=%d", MNTTAB_OPT_ACTIMEO, gopt.auto_attrcache);
112 xstrlcat(opts, preopts, l);
113 #else /* MNTTAB_OPT_ACTIMEO */
114 # ifdef MNTTAB_OPT_ACDIRMIN
115 xsnprintf(preopts, l, ",%s=%d", MNTTAB_OPT_ACTDIRMIN, gopt.auto_attrcache);
116 xstrlcat(opts, preopts, l);
117 # endif /* MNTTAB_OPT_ACDIRMIN */
118 # ifdef MNTTAB_OPT_ACDIRMAX
119 xsnprintf(preopts, l, ",%s=%d", MNTTAB_OPT_ACTDIRMAX, gopt.auto_attrcache);
120 xstrlcat(opts, preopts, l);
121 # endif /* MNTTAB_OPT_ACDIRMAX */
122 # ifdef MNTTAB_OPT_ACREGMIN
123 xsnprintf(preopts, l, ",%s=%d", MNTTAB_OPT_ACTREGMIN, gopt.auto_attrcache);
124 xstrlcat(opts, preopts, l);
125 # endif /* MNTTAB_OPT_ACREGMIN */
126 # ifdef MNTTAB_OPT_ACREGMAX
127 xsnprintf(preopts, l, ",%s=%d", MNTTAB_OPT_ACTREGMAX, gopt.auto_attrcache);
128 xstrlcat(opts, preopts, l);
129 # endif /* MNTTAB_OPT_ACREGMAX */
130 #endif /* MNTTAB_OPT_ACTIMEO */
131 }
132
133
134 /*
135 * Initialize a top-level mount. In our case, if the user asked for
136 * forced_unmounts, and the OS supports it, then we try forced/lazy unmounts
137 * on any previous toplvl mounts. This is useful if a previous Amd died and
138 * left behind toplvl mount points (this Amd will clean them up).
139 *
140 * WARNING: Don't use forced/lazy unmounts if you have another valid Amd
141 * running, because this code WILL force those valid toplvl mount points to
142 * be detached as well!
143 */
144 static int
amfs_toplvl_init(mntfs * mf)145 amfs_toplvl_init(mntfs *mf)
146 {
147 int error = 0;
148
149 #if (defined(MNT2_GEN_OPT_FORCE) || defined(MNT2_GEN_OPT_DETACH)) && (defined(HAVE_UVMOUNT) || defined(HAVE_UMOUNT2))
150 if (gopt.flags & CFM_FORCED_UNMOUNTS) {
151 plog(XLOG_INFO, "amfs_toplvl_init: trying forced/lazy unmount of %s",
152 mf->mf_mount);
153 error = umount2_fs(mf->mf_mount, AMU_UMOUNT_FORCE | AMU_UMOUNT_DETACH);
154 if (error)
155 plog(XLOG_INFO, "amfs_toplvl_init: forced/lazy unmount failed: %m");
156 else
157 dlog("amfs_toplvl_init: forced/lazy unmount succeeded");
158 }
159 #endif /* (MNT2_GEN_OPT_FORCE || MNT2_GEN_OPT_DETACH) && (HAVE_UVMOUNT || HAVE_UMOUNT2) */
160 return error;
161 }
162
163
164 /*
165 * Mount the top-level
166 */
167 int
amfs_toplvl_mount(am_node * mp,mntfs * mf)168 amfs_toplvl_mount(am_node *mp, mntfs *mf)
169 {
170 struct stat stb;
171 char opts[SIZEOF_OPTS], preopts[SIZEOF_OPTS], toplvl_opts[40];
172 int error;
173
174 /*
175 * Mounting the automounter.
176 * Make sure the mount directory exists, construct
177 * the mount options and call the mount_amfs_toplvl routine.
178 */
179
180 if (stat(mp->am_path, &stb) < 0) {
181 return errno;
182 } else if ((stb.st_mode & S_IFMT) != S_IFDIR) {
183 plog(XLOG_WARNING, "%s is not a directory", mp->am_path);
184 return ENOTDIR;
185 }
186
187 /*
188 * Construct some mount options:
189 *
190 * Tack on magic map=<mapname> option in mtab to emulate
191 * SunOS automounter behavior.
192 */
193
194 #ifdef HAVE_FS_AUTOFS
195 if (mf->mf_flags & MFF_IS_AUTOFS) {
196 autofs_get_opts(opts, sizeof(opts), mp->am_autofs_fh);
197 } else
198 #endif /* HAVE_FS_AUTOFS */
199 {
200 preopts[0] = '\0';
201 #ifdef MNTTAB_OPT_INTR
202 xstrlcat(preopts, MNTTAB_OPT_INTR, sizeof(preopts));
203 xstrlcat(preopts, ",", sizeof(preopts));
204 #endif /* MNTTAB_OPT_INTR */
205 #ifdef MNTTAB_OPT_IGNORE
206 xstrlcat(preopts, MNTTAB_OPT_IGNORE, sizeof(preopts));
207 xstrlcat(preopts, ",", sizeof(preopts));
208 #endif /* MNTTAB_OPT_IGNORE */
209 /* write most of the initial options + preopts */
210 xsnprintf(opts, sizeof(opts), "%s%s,%s=%d,%s,map=%s",
211 preopts,
212 MNTTAB_OPT_RW,
213 MNTTAB_OPT_PORT, nfs_port,
214 mf->mf_ops->fs_type, mf->mf_info);
215
216 /* process toplvl timeo/retrans options, if any */
217 if (gopt.amfs_auto_timeo[AMU_TYPE_TOPLVL] > 0) {
218 xsnprintf(toplvl_opts, sizeof(toplvl_opts), ",%s=%d",
219 MNTTAB_OPT_TIMEO, gopt.amfs_auto_timeo[AMU_TYPE_TOPLVL]);
220 xstrlcat(opts, toplvl_opts, sizeof(opts));
221 }
222 if (gopt.amfs_auto_retrans[AMU_TYPE_TOPLVL] > 0) {
223 xsnprintf(toplvl_opts, sizeof(toplvl_opts), ",%s=%d",
224 MNTTAB_OPT_RETRANS, gopt.amfs_auto_retrans[AMU_TYPE_TOPLVL]);
225 xstrlcat(opts, toplvl_opts, sizeof(opts));
226 }
227
228 #ifdef MNTTAB_OPT_NOLOCK
229 xstrlcat(opts, ",", sizeof(opts));
230 xstrlcat(opts, MNTTAB_OPT_NOLOCK, sizeof(opts));
231 #endif /* MNTTAB_OPT_NOLOCK */
232
233 #ifdef MNTTAB_OPT_NOAC
234 if (gopt.auto_attrcache == 0) {
235 xstrlcat(opts, ",", sizeof(opts));
236 xstrlcat(opts, MNTTAB_OPT_NOAC, sizeof(opts));
237 } else
238 #endif /* MNTTAB_OPT_NOAC */
239 set_auto_attrcache_timeout(preopts, opts, sizeof(preopts));
240 }
241
242 /* now do the mount */
243 error = amfs_mount(mp, mf, opts);
244 if (error) {
245 errno = error;
246 plog(XLOG_FATAL, "amfs_toplvl_mount: amfs_mount failed: %m");
247 return error;
248 }
249 return 0;
250 }
251
252
253 /*
254 * Unmount a top-level automount node
255 */
256 int
amfs_toplvl_umount(am_node * mp,mntfs * mf)257 amfs_toplvl_umount(am_node *mp, mntfs *mf)
258 {
259 struct stat stb;
260 int unmount_flags = (mf->mf_flags & MFF_ON_AUTOFS) ? AMU_UMOUNT_AUTOFS : 0;
261 int error;
262 int count = 0; /* how many times did we try to unmount? */
263
264 again:
265 /*
266 * The lstat is needed if this mount is type=direct.
267 * When that happens, the kernel cache gets confused
268 * between the underlying type (dir) and the mounted
269 * type (link) and so needs to be re-synced before
270 * the unmount. This is all because the unmount system
271 * call follows links and so can't actually unmount
272 * a link (stupid!). It was noted that doing an ls -ld
273 * of the mount point to see why things were not working
274 * actually fixed the problem - so simulate an ls -ld here.
275 */
276 if (lstat(mp->am_path, &stb) < 0) {
277 error = errno;
278 dlog("lstat(%s): %m", mp->am_path);
279 goto out;
280 }
281 if ((stb.st_mode & S_IFMT) != S_IFDIR) {
282 plog(XLOG_ERROR, "amfs_toplvl_umount: %s is not a directory, aborting.", mp->am_path);
283 error = ENOTDIR;
284 goto out;
285 }
286
287 error = UMOUNT_FS(mp->am_path, mnttab_file_name, unmount_flags);
288 if (error == EBUSY) {
289 #ifdef HAVE_FS_AUTOFS
290 /*
291 * autofs mounts are "in place", so it is possible
292 * that we can't just unmount our mount points and go away.
293 * If that's the case, just give up.
294 */
295 if (mf->mf_flags & MFF_IS_AUTOFS)
296 return error;
297 #endif /* HAVE_FS_AUTOFS */
298 plog(XLOG_WARNING, "amfs_toplvl_unmount retrying %s in 1s", mp->am_path);
299 count++;
300 sleep(1);
301 /*
302 * If user wants forced/lazy unmount semantics, then set those flags,
303 * but only after we've tried normal lstat/umount a few times --
304 * otherwise forced unmounts may hang this very same Amd (by preventing
305 * it from achieving a clean unmount).
306 */
307 if (gopt.flags & CFM_FORCED_UNMOUNTS) {
308 if (count == 5) { /* after 5 seconds, try MNT_FORCE */
309 dlog("enabling forced unmounts for toplvl node %s", mp->am_path);
310 unmount_flags |= AMU_UMOUNT_FORCE;
311 }
312 if (count == 10) { /* after 10 seconds, try MNT_DETACH */
313 dlog("enabling detached unmounts for toplvl node %s", mp->am_path);
314 unmount_flags |= AMU_UMOUNT_DETACH;
315 }
316 }
317 goto again;
318 }
319 out:
320 return error;
321 }
322