ops_cachefs.c revision 174294 
1/*
2 * Copyright (c) 1997-2006 Erez Zadok
3 * Copyright (c) 1990 Jan-Simon Pendry
4 * Copyright (c) 1990 Imperial College of Science, Technology & Medicine
5 * Copyright (c) 1990 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 *
40 * File: am-utils/amd/ops_cachefs.c
41 *
42 */
43
44/*
45 * Caching filesystem (Solaris 2.x)
46 */
47
48#ifdef HAVE_CONFIG_H
49# include <config.h>
50#endif /* HAVE_CONFIG_H */
51#include <am_defs.h>
52#include <amd.h>
53
54/* forward declarations */
55static char *cachefs_match(am_opts *fo);
56static int cachefs_init(mntfs *mf);
57static int cachefs_mount(am_node *am, mntfs *mf);
58static int cachefs_umount(am_node *am, mntfs *mf);
59
60
61/*
62 * Ops structure
63 */
64am_ops cachefs_ops =
65{
66  "cachefs",
67  cachefs_match,
68  cachefs_init,
69  cachefs_mount,
70  cachefs_umount,
71  amfs_error_lookup_child,
72  amfs_error_mount_child,
73  amfs_error_readdir,
74  0,				/* cachefs_readlink */
75  0,				/* cachefs_mounted */
76  0,				/* cachefs_umounted */
77  amfs_generic_find_srvr,
78  0,				/* cachefs_get_wchan */
79  FS_MKMNT | FS_NOTIMEOUT | FS_UBACKGROUND | FS_AMQINFO, /* nfs_fs_flags */
80#ifdef HAVE_FS_AUTOFS
81  AUTOFS_CACHEFS_FS_FLAGS,
82#endif /* HAVE_FS_AUTOFS */
83};
84
85
86/*
87 * Check that f/s has all needed fields.
88 * Returns: matched string if found, NULL otherwise.
89 */
90static char *
91cachefs_match(am_opts *fo)
92{
93  /* sanity check */
94  if (!fo->opt_rfs || !fo->opt_fs || !fo->opt_cachedir) {
95    plog(XLOG_USER, "cachefs: must specify cachedir, rfs, and fs");
96    return NULL;
97  }
98
99  dlog("CACHEFS: using cache directory \"%s\"", fo->opt_cachedir);
100
101  /* determine magic cookie to put in mtab */
102  return strdup(fo->opt_cachedir);
103}
104
105
106/*
107 * Initialize.
108 * Returns: 0 if OK, non-zero (errno) if failed.
109 */
110static int
111cachefs_init(mntfs *mf)
112{
113  /*
114   * Save cache directory name
115   */
116  if (!mf->mf_private) {
117    mf->mf_private = (voidp) strdup(mf->mf_fo->opt_cachedir);
118    mf->mf_prfree = (void (*)(voidp)) free;
119  }
120
121  return 0;
122}
123
124
125/*
126 * mntpt is the mount point ($fs) [XXX: was 'dir']
127 * backdir is the mounted pathname ($rfs) [XXX: was 'fs_name']
128 * cachedir is the cache directory ($cachedir)
129 */
130static int
131mount_cachefs(char *mntdir, char *backdir, char *cachedir,
132	      char *opts, int on_autofs)
133{
134  cachefs_args_t ca;
135  mntent_t mnt;
136  int flags;
137  char *cp;
138  MTYPE_TYPE type = MOUNT_TYPE_CACHEFS;	/* F/S mount type */
139
140  memset((voidp) &ca, 0, sizeof(ca)); /* Paranoid */
141
142  /*
143   * Fill in the mount structure
144   */
145  memset((voidp) &mnt, 0, sizeof(mnt));
146  mnt.mnt_dir = mntdir;
147  mnt.mnt_fsname = backdir;
148  mnt.mnt_type = MNTTAB_TYPE_CACHEFS;
149  mnt.mnt_opts = opts;
150
151  flags = compute_mount_flags(&mnt);
152#ifdef HAVE_FS_AUTOFS
153  if (on_autofs)
154    flags |= autofs_compute_mount_flags(&mnt);
155#endif /* HAVE_FS_AUTOFS */
156
157  /* Fill in cachefs mount arguments */
158
159  /*
160   * XXX: Caveats
161   * (1) cache directory is NOT checked for sanity beforehand, nor is it
162   * purged.  Maybe it should be purged first?
163   * (2) cache directory is NOT locked.  Should we?
164   */
165
166  /* mount flags */
167  ca.cfs_options.opt_flags = CFS_WRITE_AROUND | CFS_ACCESS_BACKFS;
168  /* cache population size */
169  ca.cfs_options.opt_popsize = DEF_POP_SIZE; /* default: 64K */
170  /* filegrp size */
171  ca.cfs_options.opt_fgsize = DEF_FILEGRP_SIZE; /* default: 256 */
172
173  /* CFS ID for file system (must be unique) */
174  ca.cfs_fsid = cachedir;
175
176  /* CFS fscdir name */
177  memset(ca.cfs_cacheid, 0, sizeof(ca.cfs_cacheid));
178  /*
179   * Append cacheid and mountpoint.
180   * sizeof(cfs_cacheid) should be C_MAX_MOUNT_FSCDIRNAME as per
181   * <sys/fs/cachefs_fs.h> (checked on Solaris 8).
182   */
183  xsnprintf(ca.cfs_cacheid, sizeof(ca.cfs_cacheid),
184	    "%s:%s", ca.cfs_fsid, mntdir);
185  /* convert '/' to '_' (Solaris does that...) */
186  cp = ca.cfs_cacheid;
187  while ((cp = strpbrk(cp, "/")) != NULL)
188    *cp = '_';
189
190  /* path for this cache dir */
191  ca.cfs_cachedir = cachedir;
192
193  /* back filesystem dir */
194  ca.cfs_backfs = backdir;
195
196  /* same as nfs values (XXX: need to handle these options) */
197  ca.cfs_acregmin = 0;
198  ca.cfs_acregmax = 0;
199  ca.cfs_acdirmin = 0;
200  ca.cfs_acdirmax = 0;
201
202  /*
203   * Call generic mount routine
204   */
205  return mount_fs(&mnt, flags, (caddr_t) &ca, 0, type, 0, NULL, mnttab_file_name, on_autofs);
206}
207
208
209static int
210cachefs_mount(am_node *am, mntfs *mf)
211{
212  int on_autofs = mf->mf_flags & MFF_ON_AUTOFS;
213  int error;
214
215  error = mount_cachefs(mf->mf_mount,
216			mf->mf_fo->opt_rfs,
217			mf->mf_fo->opt_cachedir,
218			mf->mf_mopts,
219			on_autofs);
220  if (error) {
221    errno = error;
222    /* according to Solaris, if errno==ESRCH, "options to not match" */
223    if (error == ESRCH)
224      plog(XLOG_ERROR, "mount_cachefs: options to no match: %m");
225    else
226      plog(XLOG_ERROR, "mount_cachefs: %m");
227    return error;
228  }
229
230  return 0;
231}
232
233
234static int
235cachefs_umount(am_node *am, mntfs *mf)
236{
237  int unmount_flags = (mf->mf_flags & MFF_ON_AUTOFS) ? AMU_UMOUNT_AUTOFS : 0;
238  int error;
239
240  error = UMOUNT_FS(mf->mf_mount, mnttab_file_name, unmount_flags);
241
242  /*
243   * In the case of cachefs, we must fsck the cache directory.  Otherwise,
244   * it will remain inconsistent, and the next cachefs mount will fail
245   * with the error "no space left on device" (ENOSPC).
246   *
247   * XXX: this is hacky! use fork/exec/wait instead...
248   */
249  if (!error) {
250    char *cachedir = NULL;
251    char cmd[128];
252
253    cachedir = (char *) mf->mf_private;
254    plog(XLOG_INFO, "running fsck on cache directory \"%s\"", cachedir);
255    xsnprintf(cmd, sizeof(cmd), "fsck -F cachefs %s", cachedir);
256    system(cmd);
257  }
258
259  return error;
260}
261