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ebc921ca IK |
1 | /* |
2 | * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved | |
3 | * Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org> | |
4 | * Copyright 2001-2006 Ian Kent <raven@themaw.net> | |
5 | * | |
6 | * This file is part of the Linux kernel and is made available under | |
7 | * the terms of the GNU General Public License, version 2, or at your | |
8 | * option, any later version, incorporated herein by reference. | |
9 | */ | |
10 | ||
11 | #include <linux/capability.h> | |
ebc921ca | 12 | #include <linux/compat.h> |
ebc921ca IK |
13 | |
14 | #include "autofs_i.h" | |
15 | ||
16 | static int autofs_dir_symlink(struct inode *, struct dentry *, const char *); | |
17 | static int autofs_dir_unlink(struct inode *, struct dentry *); | |
18 | static int autofs_dir_rmdir(struct inode *, struct dentry *); | |
19 | static int autofs_dir_mkdir(struct inode *, struct dentry *, umode_t); | |
20 | static long autofs_root_ioctl(struct file *, unsigned int, unsigned long); | |
21 | #ifdef CONFIG_COMPAT | |
22 | static long autofs_root_compat_ioctl(struct file *, | |
23 | unsigned int, unsigned long); | |
24 | #endif | |
25 | static int autofs_dir_open(struct inode *inode, struct file *file); | |
26 | static struct dentry *autofs_lookup(struct inode *, | |
27 | struct dentry *, unsigned int); | |
28 | static struct vfsmount *autofs_d_automount(struct path *); | |
29 | static int autofs_d_manage(const struct path *, bool); | |
30 | static void autofs_dentry_release(struct dentry *); | |
31 | ||
32 | const struct file_operations autofs_root_operations = { | |
33 | .open = dcache_dir_open, | |
34 | .release = dcache_dir_close, | |
35 | .read = generic_read_dir, | |
36 | .iterate_shared = dcache_readdir, | |
37 | .llseek = dcache_dir_lseek, | |
38 | .unlocked_ioctl = autofs_root_ioctl, | |
39 | #ifdef CONFIG_COMPAT | |
40 | .compat_ioctl = autofs_root_compat_ioctl, | |
41 | #endif | |
42 | }; | |
43 | ||
44 | const struct file_operations autofs_dir_operations = { | |
45 | .open = autofs_dir_open, | |
46 | .release = dcache_dir_close, | |
47 | .read = generic_read_dir, | |
48 | .iterate_shared = dcache_readdir, | |
49 | .llseek = dcache_dir_lseek, | |
50 | }; | |
51 | ||
52 | const struct inode_operations autofs_dir_inode_operations = { | |
53 | .lookup = autofs_lookup, | |
54 | .unlink = autofs_dir_unlink, | |
55 | .symlink = autofs_dir_symlink, | |
56 | .mkdir = autofs_dir_mkdir, | |
57 | .rmdir = autofs_dir_rmdir, | |
58 | }; | |
59 | ||
60 | const struct dentry_operations autofs_dentry_operations = { | |
61 | .d_automount = autofs_d_automount, | |
62 | .d_manage = autofs_d_manage, | |
63 | .d_release = autofs_dentry_release, | |
64 | }; | |
65 | ||
66 | static void autofs_add_active(struct dentry *dentry) | |
67 | { | |
68 | struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); | |
69 | struct autofs_info *ino; | |
70 | ||
71 | ino = autofs_dentry_ino(dentry); | |
72 | if (ino) { | |
73 | spin_lock(&sbi->lookup_lock); | |
74 | if (!ino->active_count) { | |
75 | if (list_empty(&ino->active)) | |
76 | list_add(&ino->active, &sbi->active_list); | |
77 | } | |
78 | ino->active_count++; | |
79 | spin_unlock(&sbi->lookup_lock); | |
80 | } | |
81 | } | |
82 | ||
83 | static void autofs_del_active(struct dentry *dentry) | |
84 | { | |
85 | struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); | |
86 | struct autofs_info *ino; | |
87 | ||
88 | ino = autofs_dentry_ino(dentry); | |
89 | if (ino) { | |
90 | spin_lock(&sbi->lookup_lock); | |
91 | ino->active_count--; | |
92 | if (!ino->active_count) { | |
93 | if (!list_empty(&ino->active)) | |
94 | list_del_init(&ino->active); | |
95 | } | |
96 | spin_unlock(&sbi->lookup_lock); | |
97 | } | |
98 | } | |
99 | ||
100 | static int autofs_dir_open(struct inode *inode, struct file *file) | |
101 | { | |
102 | struct dentry *dentry = file->f_path.dentry; | |
103 | struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); | |
104 | ||
105 | pr_debug("file=%p dentry=%p %pd\n", file, dentry, dentry); | |
106 | ||
107 | if (autofs_oz_mode(sbi)) | |
108 | goto out; | |
109 | ||
110 | /* | |
111 | * An empty directory in an autofs file system is always a | |
112 | * mount point. The daemon must have failed to mount this | |
113 | * during lookup so it doesn't exist. This can happen, for | |
114 | * example, if user space returns an incorrect status for a | |
115 | * mount request. Otherwise we're doing a readdir on the | |
116 | * autofs file system so just let the libfs routines handle | |
117 | * it. | |
118 | */ | |
119 | spin_lock(&sbi->lookup_lock); | |
120 | if (!path_is_mountpoint(&file->f_path) && simple_empty(dentry)) { | |
121 | spin_unlock(&sbi->lookup_lock); | |
122 | return -ENOENT; | |
123 | } | |
124 | spin_unlock(&sbi->lookup_lock); | |
125 | ||
126 | out: | |
127 | return dcache_dir_open(inode, file); | |
128 | } | |
129 | ||
130 | static void autofs_dentry_release(struct dentry *de) | |
131 | { | |
132 | struct autofs_info *ino = autofs_dentry_ino(de); | |
133 | struct autofs_sb_info *sbi = autofs_sbi(de->d_sb); | |
134 | ||
135 | pr_debug("releasing %p\n", de); | |
136 | ||
137 | if (!ino) | |
138 | return; | |
139 | ||
140 | if (sbi) { | |
141 | spin_lock(&sbi->lookup_lock); | |
142 | if (!list_empty(&ino->active)) | |
143 | list_del(&ino->active); | |
144 | if (!list_empty(&ino->expiring)) | |
145 | list_del(&ino->expiring); | |
146 | spin_unlock(&sbi->lookup_lock); | |
147 | } | |
148 | ||
149 | autofs_free_ino(ino); | |
150 | } | |
151 | ||
152 | static struct dentry *autofs_lookup_active(struct dentry *dentry) | |
153 | { | |
154 | struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); | |
155 | struct dentry *parent = dentry->d_parent; | |
156 | const struct qstr *name = &dentry->d_name; | |
157 | unsigned int len = name->len; | |
158 | unsigned int hash = name->hash; | |
159 | const unsigned char *str = name->name; | |
160 | struct list_head *p, *head; | |
161 | ||
162 | head = &sbi->active_list; | |
163 | if (list_empty(head)) | |
164 | return NULL; | |
165 | spin_lock(&sbi->lookup_lock); | |
166 | list_for_each(p, head) { | |
167 | struct autofs_info *ino; | |
168 | struct dentry *active; | |
169 | const struct qstr *qstr; | |
170 | ||
171 | ino = list_entry(p, struct autofs_info, active); | |
172 | active = ino->dentry; | |
173 | ||
174 | spin_lock(&active->d_lock); | |
175 | ||
176 | /* Already gone? */ | |
177 | if ((int) d_count(active) <= 0) | |
178 | goto next; | |
179 | ||
180 | qstr = &active->d_name; | |
181 | ||
182 | if (active->d_name.hash != hash) | |
183 | goto next; | |
184 | if (active->d_parent != parent) | |
185 | goto next; | |
186 | ||
187 | if (qstr->len != len) | |
188 | goto next; | |
189 | if (memcmp(qstr->name, str, len)) | |
190 | goto next; | |
191 | ||
192 | if (d_unhashed(active)) { | |
193 | dget_dlock(active); | |
194 | spin_unlock(&active->d_lock); | |
195 | spin_unlock(&sbi->lookup_lock); | |
196 | return active; | |
197 | } | |
198 | next: | |
199 | spin_unlock(&active->d_lock); | |
200 | } | |
201 | spin_unlock(&sbi->lookup_lock); | |
202 | ||
203 | return NULL; | |
204 | } | |
205 | ||
206 | static struct dentry *autofs_lookup_expiring(struct dentry *dentry, | |
207 | bool rcu_walk) | |
208 | { | |
209 | struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); | |
210 | struct dentry *parent = dentry->d_parent; | |
211 | const struct qstr *name = &dentry->d_name; | |
212 | unsigned int len = name->len; | |
213 | unsigned int hash = name->hash; | |
214 | const unsigned char *str = name->name; | |
215 | struct list_head *p, *head; | |
216 | ||
217 | head = &sbi->expiring_list; | |
218 | if (list_empty(head)) | |
219 | return NULL; | |
220 | spin_lock(&sbi->lookup_lock); | |
221 | list_for_each(p, head) { | |
222 | struct autofs_info *ino; | |
223 | struct dentry *expiring; | |
224 | const struct qstr *qstr; | |
225 | ||
226 | if (rcu_walk) { | |
227 | spin_unlock(&sbi->lookup_lock); | |
228 | return ERR_PTR(-ECHILD); | |
229 | } | |
230 | ||
231 | ino = list_entry(p, struct autofs_info, expiring); | |
232 | expiring = ino->dentry; | |
233 | ||
234 | spin_lock(&expiring->d_lock); | |
235 | ||
236 | /* We've already been dentry_iput or unlinked */ | |
237 | if (d_really_is_negative(expiring)) | |
238 | goto next; | |
239 | ||
240 | qstr = &expiring->d_name; | |
241 | ||
242 | if (expiring->d_name.hash != hash) | |
243 | goto next; | |
244 | if (expiring->d_parent != parent) | |
245 | goto next; | |
246 | ||
247 | if (qstr->len != len) | |
248 | goto next; | |
249 | if (memcmp(qstr->name, str, len)) | |
250 | goto next; | |
251 | ||
252 | if (d_unhashed(expiring)) { | |
253 | dget_dlock(expiring); | |
254 | spin_unlock(&expiring->d_lock); | |
255 | spin_unlock(&sbi->lookup_lock); | |
256 | return expiring; | |
257 | } | |
258 | next: | |
259 | spin_unlock(&expiring->d_lock); | |
260 | } | |
261 | spin_unlock(&sbi->lookup_lock); | |
262 | ||
263 | return NULL; | |
264 | } | |
265 | ||
266 | static int autofs_mount_wait(const struct path *path, bool rcu_walk) | |
267 | { | |
268 | struct autofs_sb_info *sbi = autofs_sbi(path->dentry->d_sb); | |
269 | struct autofs_info *ino = autofs_dentry_ino(path->dentry); | |
270 | int status = 0; | |
271 | ||
272 | if (ino->flags & AUTOFS_INF_PENDING) { | |
273 | if (rcu_walk) | |
274 | return -ECHILD; | |
275 | pr_debug("waiting for mount name=%pd\n", path->dentry); | |
276 | status = autofs_wait(sbi, path, NFY_MOUNT); | |
277 | pr_debug("mount wait done status=%d\n", status); | |
278 | } | |
279 | ino->last_used = jiffies; | |
280 | return status; | |
281 | } | |
282 | ||
283 | static int do_expire_wait(const struct path *path, bool rcu_walk) | |
284 | { | |
285 | struct dentry *dentry = path->dentry; | |
286 | struct dentry *expiring; | |
287 | ||
288 | expiring = autofs_lookup_expiring(dentry, rcu_walk); | |
289 | if (IS_ERR(expiring)) | |
290 | return PTR_ERR(expiring); | |
291 | if (!expiring) | |
292 | return autofs_expire_wait(path, rcu_walk); | |
293 | else { | |
294 | const struct path this = { .mnt = path->mnt, .dentry = expiring }; | |
295 | /* | |
296 | * If we are racing with expire the request might not | |
297 | * be quite complete, but the directory has been removed | |
298 | * so it must have been successful, just wait for it. | |
299 | */ | |
300 | autofs_expire_wait(&this, 0); | |
301 | autofs_del_expiring(expiring); | |
302 | dput(expiring); | |
303 | } | |
304 | return 0; | |
305 | } | |
306 | ||
307 | static struct dentry *autofs_mountpoint_changed(struct path *path) | |
308 | { | |
309 | struct dentry *dentry = path->dentry; | |
310 | struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); | |
311 | ||
312 | /* | |
313 | * If this is an indirect mount the dentry could have gone away | |
314 | * as a result of an expire and a new one created. | |
315 | */ | |
316 | if (autofs_type_indirect(sbi->type) && d_unhashed(dentry)) { | |
317 | struct dentry *parent = dentry->d_parent; | |
318 | struct autofs_info *ino; | |
319 | struct dentry *new; | |
320 | ||
321 | new = d_lookup(parent, &dentry->d_name); | |
322 | if (!new) | |
323 | return NULL; | |
324 | ino = autofs_dentry_ino(new); | |
325 | ino->last_used = jiffies; | |
326 | dput(path->dentry); | |
327 | path->dentry = new; | |
328 | } | |
329 | return path->dentry; | |
330 | } | |
331 | ||
332 | static struct vfsmount *autofs_d_automount(struct path *path) | |
333 | { | |
334 | struct dentry *dentry = path->dentry; | |
335 | struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); | |
336 | struct autofs_info *ino = autofs_dentry_ino(dentry); | |
337 | int status; | |
338 | ||
339 | pr_debug("dentry=%p %pd\n", dentry, dentry); | |
340 | ||
341 | /* The daemon never triggers a mount. */ | |
342 | if (autofs_oz_mode(sbi)) | |
343 | return NULL; | |
344 | ||
345 | /* | |
346 | * If an expire request is pending everyone must wait. | |
347 | * If the expire fails we're still mounted so continue | |
348 | * the follow and return. A return of -EAGAIN (which only | |
349 | * happens with indirect mounts) means the expire completed | |
350 | * and the directory was removed, so just go ahead and try | |
351 | * the mount. | |
352 | */ | |
353 | status = do_expire_wait(path, 0); | |
354 | if (status && status != -EAGAIN) | |
355 | return NULL; | |
356 | ||
357 | /* Callback to the daemon to perform the mount or wait */ | |
358 | spin_lock(&sbi->fs_lock); | |
359 | if (ino->flags & AUTOFS_INF_PENDING) { | |
360 | spin_unlock(&sbi->fs_lock); | |
361 | status = autofs_mount_wait(path, 0); | |
362 | if (status) | |
363 | return ERR_PTR(status); | |
364 | goto done; | |
365 | } | |
366 | ||
367 | /* | |
368 | * If the dentry is a symlink it's equivalent to a directory | |
369 | * having path_is_mountpoint() true, so there's no need to call | |
370 | * back to the daemon. | |
371 | */ | |
372 | if (d_really_is_positive(dentry) && d_is_symlink(dentry)) { | |
373 | spin_unlock(&sbi->fs_lock); | |
374 | goto done; | |
375 | } | |
376 | ||
377 | if (!path_is_mountpoint(path)) { | |
378 | /* | |
379 | * It's possible that user space hasn't removed directories | |
380 | * after umounting a rootless multi-mount, although it | |
381 | * should. For v5 path_has_submounts() is sufficient to | |
382 | * handle this because the leaves of the directory tree under | |
383 | * the mount never trigger mounts themselves (they have an | |
384 | * autofs trigger mount mounted on them). But v4 pseudo direct | |
385 | * mounts do need the leaves to trigger mounts. In this case | |
386 | * we have no choice but to use the list_empty() check and | |
387 | * require user space behave. | |
388 | */ | |
389 | if (sbi->version > 4) { | |
390 | if (path_has_submounts(path)) { | |
391 | spin_unlock(&sbi->fs_lock); | |
392 | goto done; | |
393 | } | |
394 | } else { | |
395 | if (!simple_empty(dentry)) { | |
396 | spin_unlock(&sbi->fs_lock); | |
397 | goto done; | |
398 | } | |
399 | } | |
400 | ino->flags |= AUTOFS_INF_PENDING; | |
401 | spin_unlock(&sbi->fs_lock); | |
402 | status = autofs_mount_wait(path, 0); | |
403 | spin_lock(&sbi->fs_lock); | |
404 | ino->flags &= ~AUTOFS_INF_PENDING; | |
405 | if (status) { | |
406 | spin_unlock(&sbi->fs_lock); | |
407 | return ERR_PTR(status); | |
408 | } | |
409 | } | |
410 | spin_unlock(&sbi->fs_lock); | |
411 | done: | |
412 | /* Mount succeeded, check if we ended up with a new dentry */ | |
413 | dentry = autofs_mountpoint_changed(path); | |
414 | if (!dentry) | |
415 | return ERR_PTR(-ENOENT); | |
416 | ||
417 | return NULL; | |
418 | } | |
419 | ||
420 | static int autofs_d_manage(const struct path *path, bool rcu_walk) | |
421 | { | |
422 | struct dentry *dentry = path->dentry; | |
423 | struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); | |
424 | struct autofs_info *ino = autofs_dentry_ino(dentry); | |
425 | int status; | |
426 | ||
427 | pr_debug("dentry=%p %pd\n", dentry, dentry); | |
428 | ||
429 | /* The daemon never waits. */ | |
430 | if (autofs_oz_mode(sbi)) { | |
431 | if (!path_is_mountpoint(path)) | |
432 | return -EISDIR; | |
433 | return 0; | |
434 | } | |
435 | ||
436 | /* Wait for pending expires */ | |
437 | if (do_expire_wait(path, rcu_walk) == -ECHILD) | |
438 | return -ECHILD; | |
439 | ||
440 | /* | |
441 | * This dentry may be under construction so wait on mount | |
442 | * completion. | |
443 | */ | |
444 | status = autofs_mount_wait(path, rcu_walk); | |
445 | if (status) | |
446 | return status; | |
447 | ||
448 | if (rcu_walk) { | |
449 | /* We don't need fs_lock in rcu_walk mode, | |
450 | * just testing 'AUTOFS_INFO_NO_RCU' is enough. | |
451 | * simple_empty() takes a spinlock, so leave it | |
452 | * to last. | |
453 | * We only return -EISDIR when certain this isn't | |
454 | * a mount-trap. | |
455 | */ | |
456 | struct inode *inode; | |
457 | ||
458 | if (ino->flags & AUTOFS_INF_WANT_EXPIRE) | |
459 | return 0; | |
460 | if (path_is_mountpoint(path)) | |
461 | return 0; | |
462 | inode = d_inode_rcu(dentry); | |
463 | if (inode && S_ISLNK(inode->i_mode)) | |
464 | return -EISDIR; | |
465 | if (list_empty(&dentry->d_subdirs)) | |
466 | return 0; | |
467 | if (!simple_empty(dentry)) | |
468 | return -EISDIR; | |
469 | return 0; | |
470 | } | |
471 | ||
472 | spin_lock(&sbi->fs_lock); | |
473 | /* | |
474 | * If the dentry has been selected for expire while we slept | |
475 | * on the lock then it might go away. We'll deal with that in | |
476 | * ->d_automount() and wait on a new mount if the expire | |
477 | * succeeds or return here if it doesn't (since there's no | |
478 | * mount to follow with a rootless multi-mount). | |
479 | */ | |
480 | if (!(ino->flags & AUTOFS_INF_EXPIRING)) { | |
481 | /* | |
482 | * Any needed mounting has been completed and the path | |
483 | * updated so check if this is a rootless multi-mount so | |
484 | * we can avoid needless calls ->d_automount() and avoid | |
485 | * an incorrect ELOOP error return. | |
486 | */ | |
487 | if ((!path_is_mountpoint(path) && !simple_empty(dentry)) || | |
488 | (d_really_is_positive(dentry) && d_is_symlink(dentry))) | |
489 | status = -EISDIR; | |
490 | } | |
491 | spin_unlock(&sbi->fs_lock); | |
492 | ||
493 | return status; | |
494 | } | |
495 | ||
496 | /* Lookups in the root directory */ | |
497 | static struct dentry *autofs_lookup(struct inode *dir, | |
498 | struct dentry *dentry, unsigned int flags) | |
499 | { | |
500 | struct autofs_sb_info *sbi; | |
501 | struct autofs_info *ino; | |
502 | struct dentry *active; | |
503 | ||
504 | pr_debug("name = %pd\n", dentry); | |
505 | ||
506 | /* File name too long to exist */ | |
507 | if (dentry->d_name.len > NAME_MAX) | |
508 | return ERR_PTR(-ENAMETOOLONG); | |
509 | ||
510 | sbi = autofs_sbi(dir->i_sb); | |
511 | ||
512 | pr_debug("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d\n", | |
9d8719a4 IK |
513 | current->pid, task_pgrp_nr(current), |
514 | sbi->flags & AUTOFS_SBI_CATATONIC, | |
ebc921ca IK |
515 | autofs_oz_mode(sbi)); |
516 | ||
517 | active = autofs_lookup_active(dentry); | |
518 | if (active) | |
519 | return active; | |
520 | else { | |
521 | /* | |
522 | * A dentry that is not within the root can never trigger a | |
523 | * mount operation, unless the directory already exists, so we | |
524 | * can return fail immediately. The daemon however does need | |
525 | * to create directories within the file system. | |
526 | */ | |
527 | if (!autofs_oz_mode(sbi) && !IS_ROOT(dentry->d_parent)) | |
528 | return ERR_PTR(-ENOENT); | |
529 | ||
530 | /* Mark entries in the root as mount triggers */ | |
531 | if (IS_ROOT(dentry->d_parent) && | |
532 | autofs_type_indirect(sbi->type)) | |
533 | __managed_dentry_set_managed(dentry); | |
534 | ||
535 | ino = autofs_new_ino(sbi); | |
536 | if (!ino) | |
537 | return ERR_PTR(-ENOMEM); | |
538 | ||
539 | dentry->d_fsdata = ino; | |
540 | ino->dentry = dentry; | |
541 | ||
542 | autofs_add_active(dentry); | |
543 | } | |
544 | return NULL; | |
545 | } | |
546 | ||
547 | static int autofs_dir_symlink(struct inode *dir, | |
548 | struct dentry *dentry, | |
549 | const char *symname) | |
550 | { | |
551 | struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb); | |
552 | struct autofs_info *ino = autofs_dentry_ino(dentry); | |
553 | struct autofs_info *p_ino; | |
554 | struct inode *inode; | |
555 | size_t size = strlen(symname); | |
556 | char *cp; | |
557 | ||
558 | pr_debug("%s <- %pd\n", symname, dentry); | |
559 | ||
560 | if (!autofs_oz_mode(sbi)) | |
561 | return -EACCES; | |
562 | ||
d4d79b81 IK |
563 | /* autofs_oz_mode() needs to allow path walks when the |
564 | * autofs mount is catatonic but the state of an autofs | |
565 | * file system needs to be preserved over restarts. | |
566 | */ | |
9d8719a4 | 567 | if (sbi->flags & AUTOFS_SBI_CATATONIC) |
d4d79b81 IK |
568 | return -EACCES; |
569 | ||
ebc921ca IK |
570 | BUG_ON(!ino); |
571 | ||
572 | autofs_clean_ino(ino); | |
573 | ||
574 | autofs_del_active(dentry); | |
575 | ||
576 | cp = kmalloc(size + 1, GFP_KERNEL); | |
577 | if (!cp) | |
578 | return -ENOMEM; | |
579 | ||
580 | strcpy(cp, symname); | |
581 | ||
582 | inode = autofs_get_inode(dir->i_sb, S_IFLNK | 0555); | |
583 | if (!inode) { | |
584 | kfree(cp); | |
585 | return -ENOMEM; | |
586 | } | |
587 | inode->i_private = cp; | |
588 | inode->i_size = size; | |
589 | d_add(dentry, inode); | |
590 | ||
591 | dget(dentry); | |
592 | atomic_inc(&ino->count); | |
593 | p_ino = autofs_dentry_ino(dentry->d_parent); | |
594 | if (p_ino && !IS_ROOT(dentry)) | |
595 | atomic_inc(&p_ino->count); | |
596 | ||
597 | dir->i_mtime = current_time(dir); | |
598 | ||
599 | return 0; | |
600 | } | |
601 | ||
602 | /* | |
603 | * NOTE! | |
604 | * | |
605 | * Normal filesystems would do a "d_delete()" to tell the VFS dcache | |
606 | * that the file no longer exists. However, doing that means that the | |
607 | * VFS layer can turn the dentry into a negative dentry. We don't want | |
608 | * this, because the unlink is probably the result of an expire. | |
609 | * We simply d_drop it and add it to a expiring list in the super block, | |
610 | * which allows the dentry lookup to check for an incomplete expire. | |
611 | * | |
612 | * If a process is blocked on the dentry waiting for the expire to finish, | |
613 | * it will invalidate the dentry and try to mount with a new one. | |
614 | * | |
615 | * Also see autofs_dir_rmdir().. | |
616 | */ | |
617 | static int autofs_dir_unlink(struct inode *dir, struct dentry *dentry) | |
618 | { | |
619 | struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb); | |
620 | struct autofs_info *ino = autofs_dentry_ino(dentry); | |
621 | struct autofs_info *p_ino; | |
622 | ||
d4d79b81 IK |
623 | if (!autofs_oz_mode(sbi)) |
624 | return -EACCES; | |
625 | ||
626 | /* autofs_oz_mode() needs to allow path walks when the | |
627 | * autofs mount is catatonic but the state of an autofs | |
628 | * file system needs to be preserved over restarts. | |
629 | */ | |
9d8719a4 | 630 | if (sbi->flags & AUTOFS_SBI_CATATONIC) |
d4d79b81 | 631 | return -EACCES; |
ebc921ca IK |
632 | |
633 | if (atomic_dec_and_test(&ino->count)) { | |
634 | p_ino = autofs_dentry_ino(dentry->d_parent); | |
635 | if (p_ino && !IS_ROOT(dentry)) | |
636 | atomic_dec(&p_ino->count); | |
637 | } | |
638 | dput(ino->dentry); | |
639 | ||
640 | d_inode(dentry)->i_size = 0; | |
641 | clear_nlink(d_inode(dentry)); | |
642 | ||
643 | dir->i_mtime = current_time(dir); | |
644 | ||
645 | spin_lock(&sbi->lookup_lock); | |
646 | __autofs_add_expiring(dentry); | |
647 | d_drop(dentry); | |
648 | spin_unlock(&sbi->lookup_lock); | |
649 | ||
650 | return 0; | |
651 | } | |
652 | ||
653 | /* | |
654 | * Version 4 of autofs provides a pseudo direct mount implementation | |
655 | * that relies on directories at the leaves of a directory tree under | |
656 | * an indirect mount to trigger mounts. To allow for this we need to | |
657 | * set the DMANAGED_AUTOMOUNT and DMANAGED_TRANSIT flags on the leaves | |
658 | * of the directory tree. There is no need to clear the automount flag | |
659 | * following a mount or restore it after an expire because these mounts | |
660 | * are always covered. However, it is necessary to ensure that these | |
661 | * flags are clear on non-empty directories to avoid unnecessary calls | |
662 | * during path walks. | |
663 | */ | |
664 | static void autofs_set_leaf_automount_flags(struct dentry *dentry) | |
665 | { | |
666 | struct dentry *parent; | |
667 | ||
668 | /* root and dentrys in the root are already handled */ | |
669 | if (IS_ROOT(dentry->d_parent)) | |
670 | return; | |
671 | ||
672 | managed_dentry_set_managed(dentry); | |
673 | ||
674 | parent = dentry->d_parent; | |
675 | /* only consider parents below dentrys in the root */ | |
676 | if (IS_ROOT(parent->d_parent)) | |
677 | return; | |
678 | managed_dentry_clear_managed(parent); | |
679 | } | |
680 | ||
681 | static void autofs_clear_leaf_automount_flags(struct dentry *dentry) | |
682 | { | |
683 | struct list_head *d_child; | |
684 | struct dentry *parent; | |
685 | ||
686 | /* flags for dentrys in the root are handled elsewhere */ | |
687 | if (IS_ROOT(dentry->d_parent)) | |
688 | return; | |
689 | ||
690 | managed_dentry_clear_managed(dentry); | |
691 | ||
692 | parent = dentry->d_parent; | |
693 | /* only consider parents below dentrys in the root */ | |
694 | if (IS_ROOT(parent->d_parent)) | |
695 | return; | |
696 | d_child = &dentry->d_child; | |
697 | /* Set parent managed if it's becoming empty */ | |
698 | if (d_child->next == &parent->d_subdirs && | |
699 | d_child->prev == &parent->d_subdirs) | |
700 | managed_dentry_set_managed(parent); | |
701 | } | |
702 | ||
703 | static int autofs_dir_rmdir(struct inode *dir, struct dentry *dentry) | |
704 | { | |
705 | struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb); | |
706 | struct autofs_info *ino = autofs_dentry_ino(dentry); | |
707 | struct autofs_info *p_ino; | |
708 | ||
709 | pr_debug("dentry %p, removing %pd\n", dentry, dentry); | |
710 | ||
711 | if (!autofs_oz_mode(sbi)) | |
712 | return -EACCES; | |
713 | ||
d4d79b81 IK |
714 | /* autofs_oz_mode() needs to allow path walks when the |
715 | * autofs mount is catatonic but the state of an autofs | |
716 | * file system needs to be preserved over restarts. | |
717 | */ | |
9d8719a4 | 718 | if (sbi->flags & AUTOFS_SBI_CATATONIC) |
d4d79b81 IK |
719 | return -EACCES; |
720 | ||
ebc921ca IK |
721 | spin_lock(&sbi->lookup_lock); |
722 | if (!simple_empty(dentry)) { | |
723 | spin_unlock(&sbi->lookup_lock); | |
724 | return -ENOTEMPTY; | |
725 | } | |
726 | __autofs_add_expiring(dentry); | |
727 | d_drop(dentry); | |
728 | spin_unlock(&sbi->lookup_lock); | |
729 | ||
730 | if (sbi->version < 5) | |
731 | autofs_clear_leaf_automount_flags(dentry); | |
732 | ||
733 | if (atomic_dec_and_test(&ino->count)) { | |
734 | p_ino = autofs_dentry_ino(dentry->d_parent); | |
735 | if (p_ino && dentry->d_parent != dentry) | |
736 | atomic_dec(&p_ino->count); | |
737 | } | |
738 | dput(ino->dentry); | |
739 | d_inode(dentry)->i_size = 0; | |
740 | clear_nlink(d_inode(dentry)); | |
741 | ||
742 | if (dir->i_nlink) | |
743 | drop_nlink(dir); | |
744 | ||
745 | return 0; | |
746 | } | |
747 | ||
748 | static int autofs_dir_mkdir(struct inode *dir, | |
749 | struct dentry *dentry, umode_t mode) | |
750 | { | |
751 | struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb); | |
752 | struct autofs_info *ino = autofs_dentry_ino(dentry); | |
753 | struct autofs_info *p_ino; | |
754 | struct inode *inode; | |
755 | ||
756 | if (!autofs_oz_mode(sbi)) | |
757 | return -EACCES; | |
758 | ||
d4d79b81 IK |
759 | /* autofs_oz_mode() needs to allow path walks when the |
760 | * autofs mount is catatonic but the state of an autofs | |
761 | * file system needs to be preserved over restarts. | |
762 | */ | |
9d8719a4 | 763 | if (sbi->flags & AUTOFS_SBI_CATATONIC) |
d4d79b81 IK |
764 | return -EACCES; |
765 | ||
ebc921ca IK |
766 | pr_debug("dentry %p, creating %pd\n", dentry, dentry); |
767 | ||
768 | BUG_ON(!ino); | |
769 | ||
770 | autofs_clean_ino(ino); | |
771 | ||
772 | autofs_del_active(dentry); | |
773 | ||
774 | inode = autofs_get_inode(dir->i_sb, S_IFDIR | mode); | |
775 | if (!inode) | |
776 | return -ENOMEM; | |
777 | d_add(dentry, inode); | |
778 | ||
779 | if (sbi->version < 5) | |
780 | autofs_set_leaf_automount_flags(dentry); | |
781 | ||
782 | dget(dentry); | |
783 | atomic_inc(&ino->count); | |
784 | p_ino = autofs_dentry_ino(dentry->d_parent); | |
785 | if (p_ino && !IS_ROOT(dentry)) | |
786 | atomic_inc(&p_ino->count); | |
787 | inc_nlink(dir); | |
788 | dir->i_mtime = current_time(dir); | |
789 | ||
790 | return 0; | |
791 | } | |
792 | ||
793 | /* Get/set timeout ioctl() operation */ | |
794 | #ifdef CONFIG_COMPAT | |
795 | static inline int autofs_compat_get_set_timeout(struct autofs_sb_info *sbi, | |
796 | compat_ulong_t __user *p) | |
797 | { | |
798 | unsigned long ntimeout; | |
799 | int rv; | |
800 | ||
801 | rv = get_user(ntimeout, p); | |
802 | if (rv) | |
803 | goto error; | |
804 | ||
805 | rv = put_user(sbi->exp_timeout/HZ, p); | |
806 | if (rv) | |
807 | goto error; | |
808 | ||
809 | if (ntimeout > UINT_MAX/HZ) | |
810 | sbi->exp_timeout = 0; | |
811 | else | |
812 | sbi->exp_timeout = ntimeout * HZ; | |
813 | ||
814 | return 0; | |
815 | error: | |
816 | return rv; | |
817 | } | |
818 | #endif | |
819 | ||
820 | static inline int autofs_get_set_timeout(struct autofs_sb_info *sbi, | |
821 | unsigned long __user *p) | |
822 | { | |
823 | unsigned long ntimeout; | |
824 | int rv; | |
825 | ||
826 | rv = get_user(ntimeout, p); | |
827 | if (rv) | |
828 | goto error; | |
829 | ||
830 | rv = put_user(sbi->exp_timeout/HZ, p); | |
831 | if (rv) | |
832 | goto error; | |
833 | ||
834 | if (ntimeout > ULONG_MAX/HZ) | |
835 | sbi->exp_timeout = 0; | |
836 | else | |
837 | sbi->exp_timeout = ntimeout * HZ; | |
838 | ||
839 | return 0; | |
840 | error: | |
841 | return rv; | |
842 | } | |
843 | ||
844 | /* Return protocol version */ | |
845 | static inline int autofs_get_protover(struct autofs_sb_info *sbi, | |
846 | int __user *p) | |
847 | { | |
848 | return put_user(sbi->version, p); | |
849 | } | |
850 | ||
851 | /* Return protocol sub version */ | |
852 | static inline int autofs_get_protosubver(struct autofs_sb_info *sbi, | |
853 | int __user *p) | |
854 | { | |
855 | return put_user(sbi->sub_version, p); | |
856 | } | |
857 | ||
858 | /* | |
859 | * Tells the daemon whether it can umount the autofs mount. | |
860 | */ | |
861 | static inline int autofs_ask_umount(struct vfsmount *mnt, int __user *p) | |
862 | { | |
863 | int status = 0; | |
864 | ||
865 | if (may_umount(mnt)) | |
866 | status = 1; | |
867 | ||
868 | pr_debug("may umount %d\n", status); | |
869 | ||
870 | status = put_user(status, p); | |
871 | ||
872 | return status; | |
873 | } | |
874 | ||
875 | /* Identify autofs_dentries - this is so we can tell if there's | |
876 | * an extra dentry refcount or not. We only hold a refcount on the | |
877 | * dentry if its non-negative (ie, d_inode != NULL) | |
878 | */ | |
879 | int is_autofs_dentry(struct dentry *dentry) | |
880 | { | |
881 | return dentry && d_really_is_positive(dentry) && | |
882 | dentry->d_op == &autofs_dentry_operations && | |
883 | dentry->d_fsdata != NULL; | |
884 | } | |
885 | ||
886 | /* | |
887 | * ioctl()'s on the root directory is the chief method for the daemon to | |
888 | * generate kernel reactions | |
889 | */ | |
890 | static int autofs_root_ioctl_unlocked(struct inode *inode, struct file *filp, | |
891 | unsigned int cmd, unsigned long arg) | |
892 | { | |
893 | struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb); | |
894 | void __user *p = (void __user *)arg; | |
895 | ||
896 | pr_debug("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u\n", | |
897 | cmd, arg, sbi, task_pgrp_nr(current)); | |
898 | ||
899 | if (_IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) || | |
900 | _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT) | |
901 | return -ENOTTY; | |
902 | ||
903 | if (!autofs_oz_mode(sbi) && !capable(CAP_SYS_ADMIN)) | |
904 | return -EPERM; | |
905 | ||
906 | switch (cmd) { | |
907 | case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */ | |
908 | return autofs_wait_release(sbi, (autofs_wqt_t) arg, 0); | |
909 | case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */ | |
910 | return autofs_wait_release(sbi, (autofs_wqt_t) arg, -ENOENT); | |
911 | case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */ | |
912 | autofs_catatonic_mode(sbi); | |
913 | return 0; | |
914 | case AUTOFS_IOC_PROTOVER: /* Get protocol version */ | |
915 | return autofs_get_protover(sbi, p); | |
916 | case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */ | |
917 | return autofs_get_protosubver(sbi, p); | |
918 | case AUTOFS_IOC_SETTIMEOUT: | |
919 | return autofs_get_set_timeout(sbi, p); | |
920 | #ifdef CONFIG_COMPAT | |
921 | case AUTOFS_IOC_SETTIMEOUT32: | |
922 | return autofs_compat_get_set_timeout(sbi, p); | |
923 | #endif | |
924 | ||
925 | case AUTOFS_IOC_ASKUMOUNT: | |
926 | return autofs_ask_umount(filp->f_path.mnt, p); | |
927 | ||
928 | /* return a single thing to expire */ | |
929 | case AUTOFS_IOC_EXPIRE: | |
930 | return autofs_expire_run(inode->i_sb, filp->f_path.mnt, sbi, p); | |
931 | /* same as above, but can send multiple expires through pipe */ | |
932 | case AUTOFS_IOC_EXPIRE_MULTI: | |
933 | return autofs_expire_multi(inode->i_sb, | |
934 | filp->f_path.mnt, sbi, p); | |
935 | ||
936 | default: | |
937 | return -EINVAL; | |
938 | } | |
939 | } | |
940 | ||
941 | static long autofs_root_ioctl(struct file *filp, | |
942 | unsigned int cmd, unsigned long arg) | |
943 | { | |
944 | struct inode *inode = file_inode(filp); | |
945 | ||
946 | return autofs_root_ioctl_unlocked(inode, filp, cmd, arg); | |
947 | } | |
948 | ||
949 | #ifdef CONFIG_COMPAT | |
950 | static long autofs_root_compat_ioctl(struct file *filp, | |
951 | unsigned int cmd, unsigned long arg) | |
952 | { | |
953 | struct inode *inode = file_inode(filp); | |
954 | int ret; | |
955 | ||
956 | if (cmd == AUTOFS_IOC_READY || cmd == AUTOFS_IOC_FAIL) | |
957 | ret = autofs_root_ioctl_unlocked(inode, filp, cmd, arg); | |
958 | else | |
959 | ret = autofs_root_ioctl_unlocked(inode, filp, cmd, | |
960 | (unsigned long) compat_ptr(arg)); | |
961 | ||
962 | return ret; | |
963 | } | |
964 | #endif |