1 /* -*- c -*- --------------------------------------------------------------- *
2 *
3 * linux/fs/autofs/inode.c
4 *
5 * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
6 * Copyright 2005-2006 Ian Kent <raven@themaw.net>
7 *
8 * This file is part of the Linux kernel and is made available under
9 * the terms of the GNU General Public License, version 2, or at your
10 * option, any later version, incorporated herein by reference.
11 *
12 * ------------------------------------------------------------------------- */
13
14 #include <linux/kernel.h>
15 #include <linux/slab.h>
16 #include <linux/file.h>
17 #include <linux/seq_file.h>
18 #include <linux/pagemap.h>
19 #include <linux/parser.h>
20 #include <linux/bitops.h>
21 #include <linux/magic.h>
22 #include "autofs_i.h"
23 #include <linux/module.h>
24
ino_lnkfree(struct autofs_info * ino)25 static void ino_lnkfree(struct autofs_info *ino)
26 {
27 if (ino->u.symlink) {
28 kfree(ino->u.symlink);
29 ino->u.symlink = NULL;
30 }
31 }
32
autofs4_init_ino(struct autofs_info * ino,struct autofs_sb_info * sbi,mode_t mode)33 struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
34 struct autofs_sb_info *sbi, mode_t mode)
35 {
36 int reinit = 1;
37
38 if (ino == NULL) {
39 reinit = 0;
40 ino = kmalloc(sizeof(*ino), GFP_KERNEL);
41 }
42
43 if (ino == NULL)
44 return NULL;
45
46 if (!reinit) {
47 ino->flags = 0;
48 ino->inode = NULL;
49 ino->dentry = NULL;
50 ino->size = 0;
51 INIT_LIST_HEAD(&ino->active);
52 INIT_LIST_HEAD(&ino->expiring);
53 atomic_set(&ino->count, 0);
54 }
55
56 ino->uid = 0;
57 ino->gid = 0;
58 ino->mode = mode;
59 ino->last_used = jiffies;
60
61 ino->sbi = sbi;
62
63 if (reinit && ino->free)
64 (ino->free)(ino);
65
66 memset(&ino->u, 0, sizeof(ino->u));
67
68 ino->free = NULL;
69
70 if (S_ISLNK(mode))
71 ino->free = ino_lnkfree;
72
73 return ino;
74 }
75
autofs4_free_ino(struct autofs_info * ino)76 void autofs4_free_ino(struct autofs_info *ino)
77 {
78 struct autofs_info *p_ino;
79
80 if (ino->dentry) {
81 ino->dentry->d_fsdata = NULL;
82 if (ino->dentry->d_inode) {
83 struct dentry *parent = ino->dentry->d_parent;
84 if (atomic_dec_and_test(&ino->count)) {
85 p_ino = autofs4_dentry_ino(parent);
86 if (p_ino && parent != ino->dentry)
87 atomic_dec(&p_ino->count);
88 }
89 dput(ino->dentry);
90 }
91 ino->dentry = NULL;
92 }
93 if (ino->free)
94 (ino->free)(ino);
95 kfree(ino);
96 }
97
98 /*
99 * Deal with the infamous "Busy inodes after umount ..." message.
100 *
101 * Clean up the dentry tree. This happens with autofs if the user
102 * space program goes away due to a SIGKILL, SIGSEGV etc.
103 */
autofs4_force_release(struct autofs_sb_info * sbi)104 static void autofs4_force_release(struct autofs_sb_info *sbi)
105 {
106 struct dentry *this_parent = sbi->sb->s_root;
107 struct list_head *next;
108
109 if (!sbi->sb->s_root)
110 return;
111
112 spin_lock(&dcache_lock);
113 repeat:
114 next = this_parent->d_subdirs.next;
115 resume:
116 while (next != &this_parent->d_subdirs) {
117 struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
118
119 /* Negative dentry - don`t care */
120 if (!simple_positive(dentry)) {
121 next = next->next;
122 continue;
123 }
124
125 if (!list_empty(&dentry->d_subdirs)) {
126 this_parent = dentry;
127 goto repeat;
128 }
129
130 next = next->next;
131 spin_unlock(&dcache_lock);
132
133 DPRINTK("dentry %p %.*s",
134 dentry, (int)dentry->d_name.len, dentry->d_name.name);
135
136 dput(dentry);
137 spin_lock(&dcache_lock);
138 }
139
140 if (this_parent != sbi->sb->s_root) {
141 struct dentry *dentry = this_parent;
142
143 next = this_parent->d_u.d_child.next;
144 this_parent = this_parent->d_parent;
145 spin_unlock(&dcache_lock);
146 DPRINTK("parent dentry %p %.*s",
147 dentry, (int)dentry->d_name.len, dentry->d_name.name);
148 dput(dentry);
149 spin_lock(&dcache_lock);
150 goto resume;
151 }
152 spin_unlock(&dcache_lock);
153 }
154
autofs4_kill_sb(struct super_block * sb)155 void autofs4_kill_sb(struct super_block *sb)
156 {
157 struct autofs_sb_info *sbi = autofs4_sbi(sb);
158
159 /*
160 * In the event of a failure in get_sb_nodev the superblock
161 * info is not present so nothing else has been setup, so
162 * just call kill_anon_super when we are called from
163 * deactivate_super.
164 */
165 if (!sbi)
166 goto out_kill_sb;
167
168 /* Free wait queues, close pipe */
169 autofs4_catatonic_mode(sbi);
170
171 /* Clean up and release dangling references */
172 autofs4_force_release(sbi);
173
174 sb->s_fs_info = NULL;
175 kfree(sbi);
176
177 out_kill_sb:
178 DPRINTK("shutting down");
179 kill_anon_super(sb);
180 }
181
autofs4_show_options(struct seq_file * m,struct vfsmount * mnt)182 static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
183 {
184 struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
185 struct inode *root_inode = mnt->mnt_sb->s_root->d_inode;
186
187 if (!sbi)
188 return 0;
189
190 seq_printf(m, ",fd=%d", sbi->pipefd);
191 if (root_inode->i_uid != 0)
192 seq_printf(m, ",uid=%u", root_inode->i_uid);
193 if (root_inode->i_gid != 0)
194 seq_printf(m, ",gid=%u", root_inode->i_gid);
195 seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
196 seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
197 seq_printf(m, ",minproto=%d", sbi->min_proto);
198 seq_printf(m, ",maxproto=%d", sbi->max_proto);
199
200 if (autofs_type_offset(sbi->type))
201 seq_printf(m, ",offset");
202 else if (autofs_type_direct(sbi->type))
203 seq_printf(m, ",direct");
204 else
205 seq_printf(m, ",indirect");
206
207 return 0;
208 }
209
210 static const struct super_operations autofs4_sops = {
211 .statfs = simple_statfs,
212 .show_options = autofs4_show_options,
213 };
214
215 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
216 Opt_indirect, Opt_direct, Opt_offset};
217
218 static const match_table_t tokens = {
219 {Opt_fd, "fd=%u"},
220 {Opt_uid, "uid=%u"},
221 {Opt_gid, "gid=%u"},
222 {Opt_pgrp, "pgrp=%u"},
223 {Opt_minproto, "minproto=%u"},
224 {Opt_maxproto, "maxproto=%u"},
225 {Opt_indirect, "indirect"},
226 {Opt_direct, "direct"},
227 {Opt_offset, "offset"},
228 {Opt_err, NULL}
229 };
230
parse_options(char * options,int * pipefd,uid_t * uid,gid_t * gid,pid_t * pgrp,unsigned int * type,int * minproto,int * maxproto)231 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
232 pid_t *pgrp, unsigned int *type, int *minproto, int *maxproto)
233 {
234 char *p;
235 substring_t args[MAX_OPT_ARGS];
236 int option;
237
238 *uid = current_uid();
239 *gid = current_gid();
240 *pgrp = task_pgrp_nr(current);
241
242 *minproto = AUTOFS_MIN_PROTO_VERSION;
243 *maxproto = AUTOFS_MAX_PROTO_VERSION;
244
245 *pipefd = -1;
246
247 if (!options)
248 return 1;
249
250 while ((p = strsep(&options, ",")) != NULL) {
251 int token;
252 if (!*p)
253 continue;
254
255 token = match_token(p, tokens, args);
256 switch (token) {
257 case Opt_fd:
258 if (match_int(args, pipefd))
259 return 1;
260 break;
261 case Opt_uid:
262 if (match_int(args, &option))
263 return 1;
264 *uid = option;
265 break;
266 case Opt_gid:
267 if (match_int(args, &option))
268 return 1;
269 *gid = option;
270 break;
271 case Opt_pgrp:
272 if (match_int(args, &option))
273 return 1;
274 *pgrp = option;
275 break;
276 case Opt_minproto:
277 if (match_int(args, &option))
278 return 1;
279 *minproto = option;
280 break;
281 case Opt_maxproto:
282 if (match_int(args, &option))
283 return 1;
284 *maxproto = option;
285 break;
286 case Opt_indirect:
287 set_autofs_type_indirect(type);
288 break;
289 case Opt_direct:
290 set_autofs_type_direct(type);
291 break;
292 case Opt_offset:
293 set_autofs_type_offset(type);
294 break;
295 default:
296 return 1;
297 }
298 }
299 return (*pipefd < 0);
300 }
301
autofs4_mkroot(struct autofs_sb_info * sbi)302 static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
303 {
304 struct autofs_info *ino;
305
306 ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
307 if (!ino)
308 return NULL;
309
310 return ino;
311 }
312
313 static struct dentry_operations autofs4_sb_dentry_operations = {
314 .d_release = autofs4_dentry_release,
315 };
316
autofs4_fill_super(struct super_block * s,void * data,int silent)317 int autofs4_fill_super(struct super_block *s, void *data, int silent)
318 {
319 struct inode * root_inode;
320 struct dentry * root;
321 struct file * pipe;
322 int pipefd;
323 struct autofs_sb_info *sbi;
324 struct autofs_info *ino;
325
326 sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
327 if (!sbi)
328 goto fail_unlock;
329 DPRINTK("starting up, sbi = %p",sbi);
330
331 s->s_fs_info = sbi;
332 sbi->magic = AUTOFS_SBI_MAGIC;
333 sbi->pipefd = -1;
334 sbi->pipe = NULL;
335 sbi->catatonic = 1;
336 sbi->exp_timeout = 0;
337 sbi->oz_pgrp = task_pgrp_nr(current);
338 sbi->sb = s;
339 sbi->version = 0;
340 sbi->sub_version = 0;
341 set_autofs_type_indirect(&sbi->type);
342 sbi->min_proto = 0;
343 sbi->max_proto = 0;
344 mutex_init(&sbi->wq_mutex);
345 spin_lock_init(&sbi->fs_lock);
346 sbi->queues = NULL;
347 spin_lock_init(&sbi->lookup_lock);
348 INIT_LIST_HEAD(&sbi->active_list);
349 INIT_LIST_HEAD(&sbi->expiring_list);
350 s->s_blocksize = 1024;
351 s->s_blocksize_bits = 10;
352 s->s_magic = AUTOFS_SUPER_MAGIC;
353 s->s_op = &autofs4_sops;
354 s->s_time_gran = 1;
355
356 /*
357 * Get the root inode and dentry, but defer checking for errors.
358 */
359 ino = autofs4_mkroot(sbi);
360 if (!ino)
361 goto fail_free;
362 root_inode = autofs4_get_inode(s, ino);
363 if (!root_inode)
364 goto fail_ino;
365
366 root = d_alloc_root(root_inode);
367 if (!root)
368 goto fail_iput;
369 pipe = NULL;
370
371 root->d_op = &autofs4_sb_dentry_operations;
372 root->d_fsdata = ino;
373
374 /* Can this call block? */
375 if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
376 &sbi->oz_pgrp, &sbi->type, &sbi->min_proto,
377 &sbi->max_proto)) {
378 printk("autofs: called with bogus options\n");
379 goto fail_dput;
380 }
381
382 root_inode->i_fop = &autofs4_root_operations;
383 root_inode->i_op = autofs_type_trigger(sbi->type) ?
384 &autofs4_direct_root_inode_operations :
385 &autofs4_indirect_root_inode_operations;
386
387 /* Couldn't this be tested earlier? */
388 if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
389 sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
390 printk("autofs: kernel does not match daemon version "
391 "daemon (%d, %d) kernel (%d, %d)\n",
392 sbi->min_proto, sbi->max_proto,
393 AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
394 goto fail_dput;
395 }
396
397 /* Establish highest kernel protocol version */
398 if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
399 sbi->version = AUTOFS_MAX_PROTO_VERSION;
400 else
401 sbi->version = sbi->max_proto;
402 sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
403
404 DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
405 pipe = fget(pipefd);
406
407 if (!pipe) {
408 printk("autofs: could not open pipe file descriptor\n");
409 goto fail_dput;
410 }
411 if (!pipe->f_op || !pipe->f_op->write)
412 goto fail_fput;
413 sbi->pipe = pipe;
414 sbi->pipefd = pipefd;
415 sbi->catatonic = 0;
416
417 /*
418 * Success! Install the root dentry now to indicate completion.
419 */
420 s->s_root = root;
421 return 0;
422
423 /*
424 * Failure ... clean up.
425 */
426 fail_fput:
427 printk("autofs: pipe file descriptor does not contain proper ops\n");
428 fput(pipe);
429 /* fall through */
430 fail_dput:
431 dput(root);
432 goto fail_free;
433 fail_iput:
434 printk("autofs: get root dentry failed\n");
435 iput(root_inode);
436 fail_ino:
437 kfree(ino);
438 fail_free:
439 kfree(sbi);
440 s->s_fs_info = NULL;
441 fail_unlock:
442 return -EINVAL;
443 }
444
autofs4_get_inode(struct super_block * sb,struct autofs_info * inf)445 struct inode *autofs4_get_inode(struct super_block *sb,
446 struct autofs_info *inf)
447 {
448 struct inode *inode = new_inode(sb);
449
450 if (inode == NULL)
451 return NULL;
452
453 inf->inode = inode;
454 inode->i_mode = inf->mode;
455 if (sb->s_root) {
456 inode->i_uid = sb->s_root->d_inode->i_uid;
457 inode->i_gid = sb->s_root->d_inode->i_gid;
458 }
459 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
460
461 if (S_ISDIR(inf->mode)) {
462 inode->i_nlink = 2;
463 inode->i_op = &autofs4_dir_inode_operations;
464 inode->i_fop = &autofs4_dir_operations;
465 } else if (S_ISLNK(inf->mode)) {
466 inode->i_size = inf->size;
467 inode->i_op = &autofs4_symlink_inode_operations;
468 }
469
470 return inode;
471 }
472