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d6910058 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
ebc921ca IK |
2 | /* |
3 | * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved | |
4 | * Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org> | |
5 | * Copyright 2001-2006 Ian Kent <raven@themaw.net> | |
ebc921ca IK |
6 | */ |
7 | ||
8 | #include <linux/capability.h> | |
ebc921ca | 9 | #include <linux/compat.h> |
ebc921ca IK |
10 | |
11 | #include "autofs_i.h" | |
12 | ||
4609e1f1 | 13 | static int autofs_dir_permission(struct mnt_idmap *, struct inode *, int); |
7a77db95 | 14 | static int autofs_dir_symlink(struct mnt_idmap *, struct inode *, |
549c7297 | 15 | struct dentry *, const char *); |
ebc921ca IK |
16 | static int autofs_dir_unlink(struct inode *, struct dentry *); |
17 | static int autofs_dir_rmdir(struct inode *, struct dentry *); | |
c54bd91e | 18 | static int autofs_dir_mkdir(struct mnt_idmap *, struct inode *, |
549c7297 | 19 | struct dentry *, umode_t); |
ebc921ca IK |
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, | |
f71381fc | 54 | .permission = autofs_dir_permission, |
ebc921ca IK |
55 | .unlink = autofs_dir_unlink, |
56 | .symlink = autofs_dir_symlink, | |
57 | .mkdir = autofs_dir_mkdir, | |
58 | .rmdir = autofs_dir_rmdir, | |
59 | }; | |
60 | ||
61 | const struct dentry_operations autofs_dentry_operations = { | |
62 | .d_automount = autofs_d_automount, | |
63 | .d_manage = autofs_d_manage, | |
64 | .d_release = autofs_dentry_release, | |
65 | }; | |
66 | ||
ebc921ca IK |
67 | static void autofs_del_active(struct dentry *dentry) |
68 | { | |
69 | struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); | |
70 | struct autofs_info *ino; | |
71 | ||
72 | ino = autofs_dentry_ino(dentry); | |
c4931db9 AV |
73 | spin_lock(&sbi->lookup_lock); |
74 | list_del_init(&ino->active); | |
75 | spin_unlock(&sbi->lookup_lock); | |
ebc921ca IK |
76 | } |
77 | ||
78 | static int autofs_dir_open(struct inode *inode, struct file *file) | |
79 | { | |
80 | struct dentry *dentry = file->f_path.dentry; | |
81 | struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); | |
a4a87303 | 82 | struct autofs_info *ino = autofs_dentry_ino(dentry); |
ebc921ca IK |
83 | |
84 | pr_debug("file=%p dentry=%p %pd\n", file, dentry, dentry); | |
85 | ||
86 | if (autofs_oz_mode(sbi)) | |
87 | goto out; | |
88 | ||
89 | /* | |
90 | * An empty directory in an autofs file system is always a | |
91 | * mount point. The daemon must have failed to mount this | |
92 | * during lookup so it doesn't exist. This can happen, for | |
93 | * example, if user space returns an incorrect status for a | |
94 | * mount request. Otherwise we're doing a readdir on the | |
95 | * autofs file system so just let the libfs routines handle | |
96 | * it. | |
97 | */ | |
98 | spin_lock(&sbi->lookup_lock); | |
a4a87303 | 99 | if (!path_is_mountpoint(&file->f_path) && autofs_empty(ino)) { |
ebc921ca IK |
100 | spin_unlock(&sbi->lookup_lock); |
101 | return -ENOENT; | |
102 | } | |
103 | spin_unlock(&sbi->lookup_lock); | |
104 | ||
105 | out: | |
106 | return dcache_dir_open(inode, file); | |
107 | } | |
108 | ||
109 | static void autofs_dentry_release(struct dentry *de) | |
110 | { | |
111 | struct autofs_info *ino = autofs_dentry_ino(de); | |
112 | struct autofs_sb_info *sbi = autofs_sbi(de->d_sb); | |
113 | ||
114 | pr_debug("releasing %p\n", de); | |
115 | ||
116 | if (!ino) | |
117 | return; | |
118 | ||
119 | if (sbi) { | |
120 | spin_lock(&sbi->lookup_lock); | |
121 | if (!list_empty(&ino->active)) | |
122 | list_del(&ino->active); | |
123 | if (!list_empty(&ino->expiring)) | |
124 | list_del(&ino->expiring); | |
125 | spin_unlock(&sbi->lookup_lock); | |
126 | } | |
127 | ||
128 | autofs_free_ino(ino); | |
129 | } | |
130 | ||
131 | static struct dentry *autofs_lookup_active(struct dentry *dentry) | |
132 | { | |
133 | struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); | |
134 | struct dentry *parent = dentry->d_parent; | |
135 | const struct qstr *name = &dentry->d_name; | |
136 | unsigned int len = name->len; | |
137 | unsigned int hash = name->hash; | |
138 | const unsigned char *str = name->name; | |
139 | struct list_head *p, *head; | |
140 | ||
141 | head = &sbi->active_list; | |
142 | if (list_empty(head)) | |
143 | return NULL; | |
144 | spin_lock(&sbi->lookup_lock); | |
145 | list_for_each(p, head) { | |
146 | struct autofs_info *ino; | |
147 | struct dentry *active; | |
148 | const struct qstr *qstr; | |
149 | ||
150 | ino = list_entry(p, struct autofs_info, active); | |
151 | active = ino->dentry; | |
152 | ||
153 | spin_lock(&active->d_lock); | |
154 | ||
155 | /* Already gone? */ | |
156 | if ((int) d_count(active) <= 0) | |
157 | goto next; | |
158 | ||
159 | qstr = &active->d_name; | |
160 | ||
161 | if (active->d_name.hash != hash) | |
162 | goto next; | |
163 | if (active->d_parent != parent) | |
164 | goto next; | |
165 | ||
166 | if (qstr->len != len) | |
167 | goto next; | |
168 | if (memcmp(qstr->name, str, len)) | |
169 | goto next; | |
170 | ||
171 | if (d_unhashed(active)) { | |
172 | dget_dlock(active); | |
173 | spin_unlock(&active->d_lock); | |
174 | spin_unlock(&sbi->lookup_lock); | |
175 | return active; | |
176 | } | |
177 | next: | |
178 | spin_unlock(&active->d_lock); | |
179 | } | |
180 | spin_unlock(&sbi->lookup_lock); | |
181 | ||
182 | return NULL; | |
183 | } | |
184 | ||
185 | static struct dentry *autofs_lookup_expiring(struct dentry *dentry, | |
186 | bool rcu_walk) | |
187 | { | |
188 | struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); | |
189 | struct dentry *parent = dentry->d_parent; | |
190 | const struct qstr *name = &dentry->d_name; | |
191 | unsigned int len = name->len; | |
192 | unsigned int hash = name->hash; | |
193 | const unsigned char *str = name->name; | |
194 | struct list_head *p, *head; | |
195 | ||
196 | head = &sbi->expiring_list; | |
197 | if (list_empty(head)) | |
198 | return NULL; | |
199 | spin_lock(&sbi->lookup_lock); | |
200 | list_for_each(p, head) { | |
201 | struct autofs_info *ino; | |
202 | struct dentry *expiring; | |
203 | const struct qstr *qstr; | |
204 | ||
205 | if (rcu_walk) { | |
206 | spin_unlock(&sbi->lookup_lock); | |
207 | return ERR_PTR(-ECHILD); | |
208 | } | |
209 | ||
210 | ino = list_entry(p, struct autofs_info, expiring); | |
211 | expiring = ino->dentry; | |
212 | ||
213 | spin_lock(&expiring->d_lock); | |
214 | ||
215 | /* We've already been dentry_iput or unlinked */ | |
216 | if (d_really_is_negative(expiring)) | |
217 | goto next; | |
218 | ||
219 | qstr = &expiring->d_name; | |
220 | ||
221 | if (expiring->d_name.hash != hash) | |
222 | goto next; | |
223 | if (expiring->d_parent != parent) | |
224 | goto next; | |
225 | ||
226 | if (qstr->len != len) | |
227 | goto next; | |
228 | if (memcmp(qstr->name, str, len)) | |
229 | goto next; | |
230 | ||
231 | if (d_unhashed(expiring)) { | |
232 | dget_dlock(expiring); | |
233 | spin_unlock(&expiring->d_lock); | |
234 | spin_unlock(&sbi->lookup_lock); | |
235 | return expiring; | |
236 | } | |
237 | next: | |
238 | spin_unlock(&expiring->d_lock); | |
239 | } | |
240 | spin_unlock(&sbi->lookup_lock); | |
241 | ||
242 | return NULL; | |
243 | } | |
244 | ||
245 | static int autofs_mount_wait(const struct path *path, bool rcu_walk) | |
246 | { | |
247 | struct autofs_sb_info *sbi = autofs_sbi(path->dentry->d_sb); | |
248 | struct autofs_info *ino = autofs_dentry_ino(path->dentry); | |
249 | int status = 0; | |
250 | ||
251 | if (ino->flags & AUTOFS_INF_PENDING) { | |
252 | if (rcu_walk) | |
253 | return -ECHILD; | |
254 | pr_debug("waiting for mount name=%pd\n", path->dentry); | |
255 | status = autofs_wait(sbi, path, NFY_MOUNT); | |
256 | pr_debug("mount wait done status=%d\n", status); | |
f5162216 IK |
257 | ino->last_used = jiffies; |
258 | return status; | |
ebc921ca | 259 | } |
f5162216 IK |
260 | if (!(sbi->flags & AUTOFS_SBI_STRICTEXPIRE)) |
261 | ino->last_used = jiffies; | |
ebc921ca IK |
262 | return status; |
263 | } | |
264 | ||
265 | static int do_expire_wait(const struct path *path, bool rcu_walk) | |
266 | { | |
267 | struct dentry *dentry = path->dentry; | |
268 | struct dentry *expiring; | |
269 | ||
270 | expiring = autofs_lookup_expiring(dentry, rcu_walk); | |
271 | if (IS_ERR(expiring)) | |
272 | return PTR_ERR(expiring); | |
273 | if (!expiring) | |
274 | return autofs_expire_wait(path, rcu_walk); | |
275 | else { | |
276 | const struct path this = { .mnt = path->mnt, .dentry = expiring }; | |
277 | /* | |
278 | * If we are racing with expire the request might not | |
279 | * be quite complete, but the directory has been removed | |
280 | * so it must have been successful, just wait for it. | |
281 | */ | |
282 | autofs_expire_wait(&this, 0); | |
283 | autofs_del_expiring(expiring); | |
284 | dput(expiring); | |
285 | } | |
286 | return 0; | |
287 | } | |
288 | ||
289 | static struct dentry *autofs_mountpoint_changed(struct path *path) | |
290 | { | |
291 | struct dentry *dentry = path->dentry; | |
292 | struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); | |
293 | ||
ba97a0a3 IK |
294 | /* If this is an indirect mount the dentry could have gone away |
295 | * and a new one created. | |
296 | * | |
297 | * This is unusual and I can't remember the case for which it | |
298 | * was originally added now. But an example of how this can | |
299 | * happen is an autofs indirect mount that has the "browse" | |
300 | * option set and also has the "symlink" option in the autofs | |
301 | * map entry. In this case the daemon will remove the browse | |
302 | * directory and create a symlink as the mount leaving the | |
303 | * struct path stale. | |
304 | * | |
305 | * Another not so obvious case is when a mount in an autofs | |
306 | * indirect mount that uses the "nobrowse" option is being | |
307 | * expired at the same time as a path walk. If the mount has | |
308 | * been umounted but the mount point directory seen before | |
309 | * becoming unhashed (during a lockless path walk) when a stat | |
310 | * family system call is made the mount won't be re-mounted as | |
311 | * it should. In this case the mount point that's been removed | |
312 | * (by the daemon) will be stale and the a new mount point | |
313 | * dentry created. | |
ebc921ca IK |
314 | */ |
315 | if (autofs_type_indirect(sbi->type) && d_unhashed(dentry)) { | |
316 | struct dentry *parent = dentry->d_parent; | |
317 | struct autofs_info *ino; | |
318 | struct dentry *new; | |
319 | ||
320 | new = d_lookup(parent, &dentry->d_name); | |
321 | if (!new) | |
322 | return NULL; | |
323 | ino = autofs_dentry_ino(new); | |
324 | ino->last_used = jiffies; | |
325 | dput(path->dentry); | |
326 | path->dentry = new; | |
327 | } | |
328 | return path->dentry; | |
329 | } | |
330 | ||
331 | static struct vfsmount *autofs_d_automount(struct path *path) | |
332 | { | |
333 | struct dentry *dentry = path->dentry; | |
334 | struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); | |
335 | struct autofs_info *ino = autofs_dentry_ino(dentry); | |
336 | int status; | |
337 | ||
338 | pr_debug("dentry=%p %pd\n", dentry, dentry); | |
339 | ||
340 | /* The daemon never triggers a mount. */ | |
341 | if (autofs_oz_mode(sbi)) | |
342 | return NULL; | |
343 | ||
344 | /* | |
345 | * If an expire request is pending everyone must wait. | |
346 | * If the expire fails we're still mounted so continue | |
347 | * the follow and return. A return of -EAGAIN (which only | |
348 | * happens with indirect mounts) means the expire completed | |
349 | * and the directory was removed, so just go ahead and try | |
350 | * the mount. | |
351 | */ | |
352 | status = do_expire_wait(path, 0); | |
353 | if (status && status != -EAGAIN) | |
354 | return NULL; | |
355 | ||
356 | /* Callback to the daemon to perform the mount or wait */ | |
357 | spin_lock(&sbi->fs_lock); | |
358 | if (ino->flags & AUTOFS_INF_PENDING) { | |
359 | spin_unlock(&sbi->fs_lock); | |
360 | status = autofs_mount_wait(path, 0); | |
361 | if (status) | |
362 | return ERR_PTR(status); | |
363 | goto done; | |
364 | } | |
365 | ||
366 | /* | |
367 | * If the dentry is a symlink it's equivalent to a directory | |
368 | * having path_is_mountpoint() true, so there's no need to call | |
369 | * back to the daemon. | |
370 | */ | |
371 | if (d_really_is_positive(dentry) && d_is_symlink(dentry)) { | |
372 | spin_unlock(&sbi->fs_lock); | |
373 | goto done; | |
374 | } | |
375 | ||
376 | if (!path_is_mountpoint(path)) { | |
377 | /* | |
378 | * It's possible that user space hasn't removed directories | |
379 | * after umounting a rootless multi-mount, although it | |
380 | * should. For v5 path_has_submounts() is sufficient to | |
381 | * handle this because the leaves of the directory tree under | |
382 | * the mount never trigger mounts themselves (they have an | |
383 | * autofs trigger mount mounted on them). But v4 pseudo direct | |
384 | * mounts do need the leaves to trigger mounts. In this case | |
a4a87303 | 385 | * we have no choice but to use the autofs_empty() check and |
ebc921ca IK |
386 | * require user space behave. |
387 | */ | |
388 | if (sbi->version > 4) { | |
389 | if (path_has_submounts(path)) { | |
390 | spin_unlock(&sbi->fs_lock); | |
391 | goto done; | |
392 | } | |
393 | } else { | |
a4a87303 | 394 | if (!autofs_empty(ino)) { |
ebc921ca IK |
395 | spin_unlock(&sbi->fs_lock); |
396 | goto done; | |
397 | } | |
398 | } | |
399 | ino->flags |= AUTOFS_INF_PENDING; | |
400 | spin_unlock(&sbi->fs_lock); | |
401 | status = autofs_mount_wait(path, 0); | |
402 | spin_lock(&sbi->fs_lock); | |
403 | ino->flags &= ~AUTOFS_INF_PENDING; | |
404 | if (status) { | |
405 | spin_unlock(&sbi->fs_lock); | |
406 | return ERR_PTR(status); | |
407 | } | |
408 | } | |
409 | spin_unlock(&sbi->fs_lock); | |
410 | done: | |
411 | /* Mount succeeded, check if we ended up with a new dentry */ | |
412 | dentry = autofs_mountpoint_changed(path); | |
413 | if (!dentry) | |
414 | return ERR_PTR(-ENOENT); | |
415 | ||
416 | return NULL; | |
417 | } | |
418 | ||
419 | static int autofs_d_manage(const struct path *path, bool rcu_walk) | |
420 | { | |
421 | struct dentry *dentry = path->dentry; | |
422 | struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); | |
423 | struct autofs_info *ino = autofs_dentry_ino(dentry); | |
424 | int status; | |
425 | ||
426 | pr_debug("dentry=%p %pd\n", dentry, dentry); | |
427 | ||
428 | /* The daemon never waits. */ | |
429 | if (autofs_oz_mode(sbi)) { | |
430 | if (!path_is_mountpoint(path)) | |
431 | return -EISDIR; | |
432 | return 0; | |
433 | } | |
434 | ||
435 | /* Wait for pending expires */ | |
436 | if (do_expire_wait(path, rcu_walk) == -ECHILD) | |
437 | return -ECHILD; | |
438 | ||
439 | /* | |
440 | * This dentry may be under construction so wait on mount | |
441 | * completion. | |
442 | */ | |
443 | status = autofs_mount_wait(path, rcu_walk); | |
444 | if (status) | |
445 | return status; | |
446 | ||
447 | if (rcu_walk) { | |
448 | /* We don't need fs_lock in rcu_walk mode, | |
a4a87303 IK |
449 | * just testing 'AUTOFS_INF_WANT_EXPIRE' is enough. |
450 | * | |
ebc921ca IK |
451 | * We only return -EISDIR when certain this isn't |
452 | * a mount-trap. | |
453 | */ | |
454 | struct inode *inode; | |
455 | ||
456 | if (ino->flags & AUTOFS_INF_WANT_EXPIRE) | |
457 | return 0; | |
458 | if (path_is_mountpoint(path)) | |
459 | return 0; | |
460 | inode = d_inode_rcu(dentry); | |
461 | if (inode && S_ISLNK(inode->i_mode)) | |
462 | return -EISDIR; | |
a4a87303 | 463 | if (!autofs_empty(ino)) |
ebc921ca IK |
464 | return -EISDIR; |
465 | return 0; | |
466 | } | |
467 | ||
468 | spin_lock(&sbi->fs_lock); | |
469 | /* | |
470 | * If the dentry has been selected for expire while we slept | |
471 | * on the lock then it might go away. We'll deal with that in | |
472 | * ->d_automount() and wait on a new mount if the expire | |
473 | * succeeds or return here if it doesn't (since there's no | |
474 | * mount to follow with a rootless multi-mount). | |
475 | */ | |
476 | if (!(ino->flags & AUTOFS_INF_EXPIRING)) { | |
477 | /* | |
478 | * Any needed mounting has been completed and the path | |
479 | * updated so check if this is a rootless multi-mount so | |
480 | * we can avoid needless calls ->d_automount() and avoid | |
481 | * an incorrect ELOOP error return. | |
482 | */ | |
a4a87303 | 483 | if ((!path_is_mountpoint(path) && !autofs_empty(ino)) || |
ebc921ca IK |
484 | (d_really_is_positive(dentry) && d_is_symlink(dentry))) |
485 | status = -EISDIR; | |
486 | } | |
487 | spin_unlock(&sbi->fs_lock); | |
488 | ||
489 | return status; | |
490 | } | |
491 | ||
492 | /* Lookups in the root directory */ | |
493 | static struct dentry *autofs_lookup(struct inode *dir, | |
494 | struct dentry *dentry, unsigned int flags) | |
495 | { | |
496 | struct autofs_sb_info *sbi; | |
497 | struct autofs_info *ino; | |
498 | struct dentry *active; | |
499 | ||
500 | pr_debug("name = %pd\n", dentry); | |
501 | ||
502 | /* File name too long to exist */ | |
503 | if (dentry->d_name.len > NAME_MAX) | |
504 | return ERR_PTR(-ENAMETOOLONG); | |
505 | ||
506 | sbi = autofs_sbi(dir->i_sb); | |
507 | ||
508 | pr_debug("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d\n", | |
9d8719a4 IK |
509 | current->pid, task_pgrp_nr(current), |
510 | sbi->flags & AUTOFS_SBI_CATATONIC, | |
ebc921ca IK |
511 | autofs_oz_mode(sbi)); |
512 | ||
513 | active = autofs_lookup_active(dentry); | |
514 | if (active) | |
515 | return active; | |
516 | else { | |
517 | /* | |
518 | * A dentry that is not within the root can never trigger a | |
519 | * mount operation, unless the directory already exists, so we | |
520 | * can return fail immediately. The daemon however does need | |
521 | * to create directories within the file system. | |
522 | */ | |
523 | if (!autofs_oz_mode(sbi) && !IS_ROOT(dentry->d_parent)) | |
524 | return ERR_PTR(-ENOENT); | |
525 | ||
ebc921ca IK |
526 | ino = autofs_new_ino(sbi); |
527 | if (!ino) | |
528 | return ERR_PTR(-ENOMEM); | |
529 | ||
5f68056c AV |
530 | spin_lock(&sbi->lookup_lock); |
531 | spin_lock(&dentry->d_lock); | |
532 | /* Mark entries in the root as mount triggers */ | |
533 | if (IS_ROOT(dentry->d_parent) && | |
534 | autofs_type_indirect(sbi->type)) | |
535 | __managed_dentry_set_managed(dentry); | |
ebc921ca IK |
536 | dentry->d_fsdata = ino; |
537 | ino->dentry = dentry; | |
538 | ||
c4931db9 AV |
539 | list_add(&ino->active, &sbi->active_list); |
540 | spin_unlock(&sbi->lookup_lock); | |
5f68056c | 541 | spin_unlock(&dentry->d_lock); |
ebc921ca IK |
542 | } |
543 | return NULL; | |
544 | } | |
545 | ||
4609e1f1 | 546 | static int autofs_dir_permission(struct mnt_idmap *idmap, |
f71381fc IK |
547 | struct inode *inode, int mask) |
548 | { | |
549 | if (mask & MAY_WRITE) { | |
550 | struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb); | |
551 | ||
552 | if (!autofs_oz_mode(sbi)) | |
553 | return -EACCES; | |
554 | ||
555 | /* autofs_oz_mode() needs to allow path walks when the | |
556 | * autofs mount is catatonic but the state of an autofs | |
557 | * file system needs to be preserved over restarts. | |
558 | */ | |
559 | if (sbi->flags & AUTOFS_SBI_CATATONIC) | |
560 | return -EACCES; | |
561 | } | |
562 | ||
4609e1f1 | 563 | return generic_permission(idmap, inode, mask); |
f71381fc IK |
564 | } |
565 | ||
7a77db95 | 566 | static int autofs_dir_symlink(struct mnt_idmap *idmap, |
549c7297 CB |
567 | struct inode *dir, struct dentry *dentry, |
568 | const char *symname) | |
ebc921ca | 569 | { |
ebc921ca IK |
570 | struct autofs_info *ino = autofs_dentry_ino(dentry); |
571 | struct autofs_info *p_ino; | |
572 | struct inode *inode; | |
573 | size_t size = strlen(symname); | |
574 | char *cp; | |
575 | ||
576 | pr_debug("%s <- %pd\n", symname, dentry); | |
577 | ||
ebc921ca IK |
578 | BUG_ON(!ino); |
579 | ||
580 | autofs_clean_ino(ino); | |
581 | ||
582 | autofs_del_active(dentry); | |
583 | ||
584 | cp = kmalloc(size + 1, GFP_KERNEL); | |
585 | if (!cp) | |
586 | return -ENOMEM; | |
587 | ||
588 | strcpy(cp, symname); | |
589 | ||
590 | inode = autofs_get_inode(dir->i_sb, S_IFLNK | 0555); | |
591 | if (!inode) { | |
592 | kfree(cp); | |
593 | return -ENOMEM; | |
594 | } | |
595 | inode->i_private = cp; | |
596 | inode->i_size = size; | |
597 | d_add(dentry, inode); | |
598 | ||
599 | dget(dentry); | |
ebc921ca | 600 | p_ino = autofs_dentry_ino(dentry->d_parent); |
850d71ac | 601 | p_ino->count++; |
ebc921ca | 602 | |
2c11fd98 | 603 | inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir)); |
ebc921ca IK |
604 | |
605 | return 0; | |
606 | } | |
607 | ||
608 | /* | |
609 | * NOTE! | |
610 | * | |
611 | * Normal filesystems would do a "d_delete()" to tell the VFS dcache | |
612 | * that the file no longer exists. However, doing that means that the | |
613 | * VFS layer can turn the dentry into a negative dentry. We don't want | |
614 | * this, because the unlink is probably the result of an expire. | |
615 | * We simply d_drop it and add it to a expiring list in the super block, | |
616 | * which allows the dentry lookup to check for an incomplete expire. | |
617 | * | |
618 | * If a process is blocked on the dentry waiting for the expire to finish, | |
619 | * it will invalidate the dentry and try to mount with a new one. | |
620 | * | |
621 | * Also see autofs_dir_rmdir().. | |
622 | */ | |
623 | static int autofs_dir_unlink(struct inode *dir, struct dentry *dentry) | |
624 | { | |
625 | struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb); | |
626 | struct autofs_info *ino = autofs_dentry_ino(dentry); | |
627 | struct autofs_info *p_ino; | |
628 | ||
41ca1974 | 629 | p_ino = autofs_dentry_ino(dentry->d_parent); |
850d71ac | 630 | p_ino->count--; |
ebc921ca IK |
631 | dput(ino->dentry); |
632 | ||
633 | d_inode(dentry)->i_size = 0; | |
634 | clear_nlink(d_inode(dentry)); | |
635 | ||
2c11fd98 | 636 | inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir)); |
ebc921ca IK |
637 | |
638 | spin_lock(&sbi->lookup_lock); | |
639 | __autofs_add_expiring(dentry); | |
640 | d_drop(dentry); | |
641 | spin_unlock(&sbi->lookup_lock); | |
642 | ||
643 | return 0; | |
644 | } | |
645 | ||
646 | /* | |
647 | * Version 4 of autofs provides a pseudo direct mount implementation | |
648 | * that relies on directories at the leaves of a directory tree under | |
649 | * an indirect mount to trigger mounts. To allow for this we need to | |
650 | * set the DMANAGED_AUTOMOUNT and DMANAGED_TRANSIT flags on the leaves | |
651 | * of the directory tree. There is no need to clear the automount flag | |
652 | * following a mount or restore it after an expire because these mounts | |
653 | * are always covered. However, it is necessary to ensure that these | |
654 | * flags are clear on non-empty directories to avoid unnecessary calls | |
655 | * during path walks. | |
656 | */ | |
657 | static void autofs_set_leaf_automount_flags(struct dentry *dentry) | |
658 | { | |
659 | struct dentry *parent; | |
660 | ||
661 | /* root and dentrys in the root are already handled */ | |
662 | if (IS_ROOT(dentry->d_parent)) | |
663 | return; | |
664 | ||
665 | managed_dentry_set_managed(dentry); | |
666 | ||
667 | parent = dentry->d_parent; | |
668 | /* only consider parents below dentrys in the root */ | |
669 | if (IS_ROOT(parent->d_parent)) | |
670 | return; | |
671 | managed_dentry_clear_managed(parent); | |
672 | } | |
673 | ||
674 | static void autofs_clear_leaf_automount_flags(struct dentry *dentry) | |
675 | { | |
ebc921ca IK |
676 | struct dentry *parent; |
677 | ||
678 | /* flags for dentrys in the root are handled elsewhere */ | |
679 | if (IS_ROOT(dentry->d_parent)) | |
680 | return; | |
681 | ||
682 | managed_dentry_clear_managed(dentry); | |
683 | ||
684 | parent = dentry->d_parent; | |
685 | /* only consider parents below dentrys in the root */ | |
686 | if (IS_ROOT(parent->d_parent)) | |
687 | return; | |
850d71ac | 688 | if (autofs_dentry_ino(parent)->count == 2) |
ebc921ca IK |
689 | managed_dentry_set_managed(parent); |
690 | } | |
691 | ||
692 | static int autofs_dir_rmdir(struct inode *dir, struct dentry *dentry) | |
693 | { | |
694 | struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb); | |
695 | struct autofs_info *ino = autofs_dentry_ino(dentry); | |
696 | struct autofs_info *p_ino; | |
697 | ||
698 | pr_debug("dentry %p, removing %pd\n", dentry, dentry); | |
699 | ||
850d71ac | 700 | if (ino->count != 1) |
ebc921ca | 701 | return -ENOTEMPTY; |
c3aed166 AV |
702 | |
703 | spin_lock(&sbi->lookup_lock); | |
ebc921ca IK |
704 | __autofs_add_expiring(dentry); |
705 | d_drop(dentry); | |
706 | spin_unlock(&sbi->lookup_lock); | |
707 | ||
708 | if (sbi->version < 5) | |
709 | autofs_clear_leaf_automount_flags(dentry); | |
710 | ||
41ca1974 | 711 | p_ino = autofs_dentry_ino(dentry->d_parent); |
850d71ac | 712 | p_ino->count--; |
ebc921ca IK |
713 | dput(ino->dentry); |
714 | d_inode(dentry)->i_size = 0; | |
715 | clear_nlink(d_inode(dentry)); | |
716 | ||
717 | if (dir->i_nlink) | |
718 | drop_nlink(dir); | |
719 | ||
720 | return 0; | |
721 | } | |
722 | ||
c54bd91e | 723 | static int autofs_dir_mkdir(struct mnt_idmap *idmap, |
549c7297 CB |
724 | struct inode *dir, struct dentry *dentry, |
725 | umode_t mode) | |
ebc921ca IK |
726 | { |
727 | struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb); | |
728 | struct autofs_info *ino = autofs_dentry_ino(dentry); | |
729 | struct autofs_info *p_ino; | |
730 | struct inode *inode; | |
731 | ||
ebc921ca IK |
732 | pr_debug("dentry %p, creating %pd\n", dentry, dentry); |
733 | ||
734 | BUG_ON(!ino); | |
735 | ||
736 | autofs_clean_ino(ino); | |
737 | ||
738 | autofs_del_active(dentry); | |
739 | ||
740 | inode = autofs_get_inode(dir->i_sb, S_IFDIR | mode); | |
741 | if (!inode) | |
742 | return -ENOMEM; | |
743 | d_add(dentry, inode); | |
744 | ||
745 | if (sbi->version < 5) | |
746 | autofs_set_leaf_automount_flags(dentry); | |
747 | ||
748 | dget(dentry); | |
ebc921ca | 749 | p_ino = autofs_dentry_ino(dentry->d_parent); |
850d71ac | 750 | p_ino->count++; |
ebc921ca | 751 | inc_nlink(dir); |
2c11fd98 | 752 | inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir)); |
ebc921ca IK |
753 | |
754 | return 0; | |
755 | } | |
756 | ||
757 | /* Get/set timeout ioctl() operation */ | |
758 | #ifdef CONFIG_COMPAT | |
759 | static inline int autofs_compat_get_set_timeout(struct autofs_sb_info *sbi, | |
760 | compat_ulong_t __user *p) | |
761 | { | |
762 | unsigned long ntimeout; | |
763 | int rv; | |
764 | ||
765 | rv = get_user(ntimeout, p); | |
766 | if (rv) | |
767 | goto error; | |
768 | ||
769 | rv = put_user(sbi->exp_timeout/HZ, p); | |
770 | if (rv) | |
771 | goto error; | |
772 | ||
773 | if (ntimeout > UINT_MAX/HZ) | |
774 | sbi->exp_timeout = 0; | |
775 | else | |
776 | sbi->exp_timeout = ntimeout * HZ; | |
777 | ||
778 | return 0; | |
779 | error: | |
780 | return rv; | |
781 | } | |
782 | #endif | |
783 | ||
784 | static inline int autofs_get_set_timeout(struct autofs_sb_info *sbi, | |
785 | unsigned long __user *p) | |
786 | { | |
787 | unsigned long ntimeout; | |
788 | int rv; | |
789 | ||
790 | rv = get_user(ntimeout, p); | |
791 | if (rv) | |
792 | goto error; | |
793 | ||
794 | rv = put_user(sbi->exp_timeout/HZ, p); | |
795 | if (rv) | |
796 | goto error; | |
797 | ||
798 | if (ntimeout > ULONG_MAX/HZ) | |
799 | sbi->exp_timeout = 0; | |
800 | else | |
801 | sbi->exp_timeout = ntimeout * HZ; | |
802 | ||
803 | return 0; | |
804 | error: | |
805 | return rv; | |
806 | } | |
807 | ||
808 | /* Return protocol version */ | |
809 | static inline int autofs_get_protover(struct autofs_sb_info *sbi, | |
810 | int __user *p) | |
811 | { | |
812 | return put_user(sbi->version, p); | |
813 | } | |
814 | ||
815 | /* Return protocol sub version */ | |
816 | static inline int autofs_get_protosubver(struct autofs_sb_info *sbi, | |
817 | int __user *p) | |
818 | { | |
819 | return put_user(sbi->sub_version, p); | |
820 | } | |
821 | ||
822 | /* | |
823 | * Tells the daemon whether it can umount the autofs mount. | |
824 | */ | |
825 | static inline int autofs_ask_umount(struct vfsmount *mnt, int __user *p) | |
826 | { | |
827 | int status = 0; | |
828 | ||
829 | if (may_umount(mnt)) | |
830 | status = 1; | |
831 | ||
832 | pr_debug("may umount %d\n", status); | |
833 | ||
834 | status = put_user(status, p); | |
835 | ||
836 | return status; | |
837 | } | |
838 | ||
839 | /* Identify autofs_dentries - this is so we can tell if there's | |
840 | * an extra dentry refcount or not. We only hold a refcount on the | |
841 | * dentry if its non-negative (ie, d_inode != NULL) | |
842 | */ | |
843 | int is_autofs_dentry(struct dentry *dentry) | |
844 | { | |
845 | return dentry && d_really_is_positive(dentry) && | |
846 | dentry->d_op == &autofs_dentry_operations && | |
847 | dentry->d_fsdata != NULL; | |
848 | } | |
849 | ||
850 | /* | |
851 | * ioctl()'s on the root directory is the chief method for the daemon to | |
852 | * generate kernel reactions | |
853 | */ | |
854 | static int autofs_root_ioctl_unlocked(struct inode *inode, struct file *filp, | |
855 | unsigned int cmd, unsigned long arg) | |
856 | { | |
857 | struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb); | |
858 | void __user *p = (void __user *)arg; | |
859 | ||
860 | pr_debug("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u\n", | |
861 | cmd, arg, sbi, task_pgrp_nr(current)); | |
862 | ||
863 | if (_IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) || | |
864 | _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT) | |
865 | return -ENOTTY; | |
866 | ||
867 | if (!autofs_oz_mode(sbi) && !capable(CAP_SYS_ADMIN)) | |
868 | return -EPERM; | |
869 | ||
870 | switch (cmd) { | |
871 | case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */ | |
872 | return autofs_wait_release(sbi, (autofs_wqt_t) arg, 0); | |
873 | case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */ | |
874 | return autofs_wait_release(sbi, (autofs_wqt_t) arg, -ENOENT); | |
875 | case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */ | |
876 | autofs_catatonic_mode(sbi); | |
877 | return 0; | |
878 | case AUTOFS_IOC_PROTOVER: /* Get protocol version */ | |
879 | return autofs_get_protover(sbi, p); | |
880 | case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */ | |
881 | return autofs_get_protosubver(sbi, p); | |
882 | case AUTOFS_IOC_SETTIMEOUT: | |
883 | return autofs_get_set_timeout(sbi, p); | |
884 | #ifdef CONFIG_COMPAT | |
885 | case AUTOFS_IOC_SETTIMEOUT32: | |
886 | return autofs_compat_get_set_timeout(sbi, p); | |
887 | #endif | |
888 | ||
889 | case AUTOFS_IOC_ASKUMOUNT: | |
890 | return autofs_ask_umount(filp->f_path.mnt, p); | |
891 | ||
892 | /* return a single thing to expire */ | |
893 | case AUTOFS_IOC_EXPIRE: | |
894 | return autofs_expire_run(inode->i_sb, filp->f_path.mnt, sbi, p); | |
895 | /* same as above, but can send multiple expires through pipe */ | |
896 | case AUTOFS_IOC_EXPIRE_MULTI: | |
897 | return autofs_expire_multi(inode->i_sb, | |
898 | filp->f_path.mnt, sbi, p); | |
899 | ||
900 | default: | |
901 | return -EINVAL; | |
902 | } | |
903 | } | |
904 | ||
905 | static long autofs_root_ioctl(struct file *filp, | |
906 | unsigned int cmd, unsigned long arg) | |
907 | { | |
908 | struct inode *inode = file_inode(filp); | |
909 | ||
910 | return autofs_root_ioctl_unlocked(inode, filp, cmd, arg); | |
911 | } | |
912 | ||
913 | #ifdef CONFIG_COMPAT | |
914 | static long autofs_root_compat_ioctl(struct file *filp, | |
915 | unsigned int cmd, unsigned long arg) | |
916 | { | |
917 | struct inode *inode = file_inode(filp); | |
918 | int ret; | |
919 | ||
920 | if (cmd == AUTOFS_IOC_READY || cmd == AUTOFS_IOC_FAIL) | |
921 | ret = autofs_root_ioctl_unlocked(inode, filp, cmd, arg); | |
922 | else | |
923 | ret = autofs_root_ioctl_unlocked(inode, filp, cmd, | |
924 | (unsigned long) compat_ptr(arg)); | |
925 | ||
926 | return ret; | |
927 | } | |
928 | #endif |