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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
4 * Copyright 1999-2000 Jeremy Fitzhardinge <[email protected]>
5 * Copyright 2001-2006 Ian Kent <[email protected]>
6 */
7
8#include <linux/capability.h>
9#include <linux/compat.h>
10#include <linux/string.h>
11
12#include "autofs_i.h"
13
14static int autofs_dir_permission(const struct mnt_idmap *, struct inode *, int);
15static int autofs_dir_symlink(const struct mnt_idmap *, struct inode *,
16 struct dentry *, const char *);
17static int autofs_dir_unlink(struct inode *, struct dentry *);
18static int autofs_dir_rmdir(struct inode *, struct dentry *);
19static struct dentry *autofs_dir_mkdir(const struct mnt_idmap *, struct inode *,
20 struct dentry *, umode_t);
21static long autofs_root_ioctl(struct file *, unsigned int, unsigned long);
22#ifdef CONFIG_COMPAT
23static long autofs_root_compat_ioctl(struct file *,
24 unsigned int, unsigned long);
25#endif
26static int autofs_dir_open(struct inode *inode, struct file *file);
27static struct dentry *autofs_lookup(struct inode *,
28 struct dentry *, unsigned int);
29static struct vfsmount *autofs_d_automount(struct path *);
30static int autofs_d_manage(const struct path *, bool);
31static void autofs_dentry_release(struct dentry *);
32
33const struct file_operations autofs_root_operations = {
34 .open = dcache_dir_open,
35 .release = dcache_dir_close,
36 .read = generic_read_dir,
37 .iterate_shared = dcache_readdir,
38 .llseek = dcache_dir_lseek,
39 .unlocked_ioctl = autofs_root_ioctl,
40#ifdef CONFIG_COMPAT
41 .compat_ioctl = autofs_root_compat_ioctl,
42#endif
43};
44
45const struct file_operations autofs_dir_operations = {
46 .open = autofs_dir_open,
47 .release = dcache_dir_close,
48 .read = generic_read_dir,
49 .iterate_shared = dcache_readdir,
50 .llseek = dcache_dir_lseek,
51};
52
53const struct inode_operations autofs_dir_inode_operations = {
54 .lookup = autofs_lookup,
55 .permission = autofs_dir_permission,
56 .unlink = autofs_dir_unlink,
57 .symlink = autofs_dir_symlink,
58 .mkdir = autofs_dir_mkdir,
59 .rmdir = autofs_dir_rmdir,
60};
61
62const struct dentry_operations autofs_dentry_operations = {
63 .d_automount = autofs_d_automount,
64 .d_manage = autofs_d_manage,
65 .d_release = autofs_dentry_release,
66};
67
68static void autofs_del_active(struct dentry *dentry)
69{
70 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
71 struct autofs_info *ino;
72
73 ino = autofs_dentry_ino(dentry);
74 spin_lock(&sbi->lookup_lock);
75 list_del_init(&ino->active);
76 spin_unlock(&sbi->lookup_lock);
77}
78
79static int autofs_dir_open(struct inode *inode, struct file *file)
80{
81 struct dentry *dentry = file->f_path.dentry;
82 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
83 struct autofs_info *ino = autofs_dentry_ino(dentry);
84
85 pr_debug("file=%p dentry=%p %pd\n", file, dentry, dentry);
86
87 if (autofs_oz_mode(sbi))
88 goto out;
89
90 /*
91 * An empty directory in an autofs file system is always a
92 * mount point. The daemon must have failed to mount this
93 * during lookup so it doesn't exist. This can happen, for
94 * example, if user space returns an incorrect status for a
95 * mount request. Otherwise we're doing a readdir on the
96 * autofs file system so just let the libfs routines handle
97 * it.
98 */
99 spin_lock(&sbi->lookup_lock);
100 if (!path_is_mountpoint(&file->f_path) && autofs_empty(ino)) {
101 spin_unlock(&sbi->lookup_lock);
102 return -ENOENT;
103 }
104 spin_unlock(&sbi->lookup_lock);
105
106out:
107 return dcache_dir_open(inode, file);
108}
109
110static void autofs_dentry_release(struct dentry *de)
111{
112 struct autofs_info *ino = autofs_dentry_ino(de);
113 struct autofs_sb_info *sbi = autofs_sbi(de->d_sb);
114
115 pr_debug("releasing %p\n", de);
116
117 if (!ino)
118 return;
119
120 if (sbi) {
121 spin_lock(&sbi->lookup_lock);
122 if (!list_empty(&ino->active))
123 list_del(&ino->active);
124 if (!list_empty(&ino->expiring))
125 list_del(&ino->expiring);
126 spin_unlock(&sbi->lookup_lock);
127 }
128
129 autofs_free_ino(ino);
130}
131
132static struct dentry *autofs_lookup_active(struct dentry *dentry)
133{
134 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
135 struct dentry *parent = dentry->d_parent;
136 const struct qstr *name = &dentry->d_name;
137 unsigned int len = name->len;
138 unsigned int hash = name->hash;
139 const unsigned char *str = name->name;
140 struct list_head *p, *head;
141
142 head = &sbi->active_list;
143 if (list_empty(head))
144 return NULL;
145 spin_lock(&sbi->lookup_lock);
146 list_for_each(p, head) {
147 struct autofs_info *ino;
148 struct dentry *active;
149 const struct qstr *qstr;
150
151 ino = list_entry(p, struct autofs_info, active);
152 active = ino->dentry;
153
154 spin_lock(&active->d_lock);
155
156 /* Already gone? */
157 if ((int) d_count(active) <= 0)
158 goto next;
159
160 qstr = &active->d_name;
161
162 if (active->d_name.hash != hash)
163 goto next;
164 if (active->d_parent != parent)
165 goto next;
166
167 if (qstr->len != len)
168 goto next;
169 if (memcmp(qstr->name, str, len))
170 goto next;
171
172 if (d_unhashed(active)) {
173 dget_dlock(active);
174 spin_unlock(&active->d_lock);
175 spin_unlock(&sbi->lookup_lock);
176 return active;
177 }
178next:
179 spin_unlock(&active->d_lock);
180 }
181 spin_unlock(&sbi->lookup_lock);
182
183 return NULL;
184}
185
186static struct dentry *autofs_lookup_expiring(struct dentry *dentry,
187 bool rcu_walk)
188{
189 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
190 struct dentry *parent = dentry->d_parent;
191 const struct qstr *name = &dentry->d_name;
192 unsigned int len = name->len;
193 unsigned int hash = name->hash;
194 const unsigned char *str = name->name;
195 struct list_head *p, *head;
196
197 head = &sbi->expiring_list;
198 if (list_empty(head))
199 return NULL;
200 spin_lock(&sbi->lookup_lock);
201 list_for_each(p, head) {
202 struct autofs_info *ino;
203 struct dentry *expiring;
204 const struct qstr *qstr;
205
206 if (rcu_walk) {
207 spin_unlock(&sbi->lookup_lock);
208 return ERR_PTR(-ECHILD);
209 }
210
211 ino = list_entry(p, struct autofs_info, expiring);
212 expiring = ino->dentry;
213
214 spin_lock(&expiring->d_lock);
215
216 /* We've already been dentry_iput or unlinked */
217 if (d_really_is_negative(expiring))
218 goto next;
219
220 qstr = &expiring->d_name;
221
222 if (expiring->d_name.hash != hash)
223 goto next;
224 if (expiring->d_parent != parent)
225 goto next;
226
227 if (qstr->len != len)
228 goto next;
229 if (memcmp(qstr->name, str, len))
230 goto next;
231
232 if (d_unhashed(expiring)) {
233 dget_dlock(expiring);
234 spin_unlock(&expiring->d_lock);
235 spin_unlock(&sbi->lookup_lock);
236 return expiring;
237 }
238next:
239 spin_unlock(&expiring->d_lock);
240 }
241 spin_unlock(&sbi->lookup_lock);
242
243 return NULL;
244}
245
246static int autofs_mount_wait(const struct path *path, bool rcu_walk)
247{
248 struct autofs_sb_info *sbi = autofs_sbi(path->dentry->d_sb);
249 struct autofs_info *ino = autofs_dentry_ino(path->dentry);
250 int status = 0;
251
252 if (ino->flags & AUTOFS_INF_PENDING) {
253 if (rcu_walk)
254 return -ECHILD;
255 pr_debug("waiting for mount name=%pd\n", path->dentry);
256 status = autofs_wait(sbi, path, NFY_MOUNT);
257 pr_debug("mount wait done status=%d\n", status);
258 ino->last_used = jiffies;
259 return status;
260 }
261 if (!(sbi->flags & AUTOFS_SBI_STRICTEXPIRE))
262 ino->last_used = jiffies;
263 return status;
264}
265
266static int do_expire_wait(const struct path *path, bool rcu_walk)
267{
268 struct dentry *dentry = path->dentry;
269 struct dentry *expiring;
270
271 expiring = autofs_lookup_expiring(dentry, rcu_walk);
272 if (IS_ERR(expiring))
273 return PTR_ERR(expiring);
274 if (!expiring)
275 return autofs_expire_wait(path, rcu_walk);
276 else {
277 const struct path this = { .mnt = path->mnt, .dentry = expiring };
278 /*
279 * If we are racing with expire the request might not
280 * be quite complete, but the directory has been removed
281 * so it must have been successful, just wait for it.
282 */
283 autofs_expire_wait(&this, 0);
284 autofs_del_expiring(expiring);
285 dput(expiring);
286 }
287 return 0;
288}
289
290static struct dentry *autofs_mountpoint_changed(struct path *path)
291{
292 struct dentry *dentry = path->dentry;
293 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
294
295 /* If this is an indirect mount the dentry could have gone away
296 * and a new one created.
297 *
298 * This is unusual and I can't remember the case for which it
299 * was originally added now. But an example of how this can
300 * happen is an autofs indirect mount that has the "browse"
301 * option set and also has the "symlink" option in the autofs
302 * map entry. In this case the daemon will remove the browse
303 * directory and create a symlink as the mount leaving the
304 * struct path stale.
305 *
306 * Another not so obvious case is when a mount in an autofs
307 * indirect mount that uses the "nobrowse" option is being
308 * expired at the same time as a path walk. If the mount has
309 * been umounted but the mount point directory seen before
310 * becoming unhashed (during a lockless path walk) when a stat
311 * family system call is made the mount won't be re-mounted as
312 * it should. In this case the mount point that's been removed
313 * (by the daemon) will be stale and the a new mount point
314 * dentry 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
332static 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 /* Refuse to trigger mount if current namespace is not the owner
346 * and the mount is propagation private.
347 */
348 if (sbi->mnt_ns_id != to_ns_common(current->nsproxy->mnt_ns)->ns_id) {
349 if (vfsmount_to_propagation_flags(path->mnt) & MS_PRIVATE)
350 return ERR_PTR(-EPERM);
351 }
352
353 /*
354 * If an expire request is pending everyone must wait.
355 * If the expire fails we're still mounted so continue
356 * the follow and return. A return of -EAGAIN (which only
357 * happens with indirect mounts) means the expire completed
358 * and the directory was removed, so just go ahead and try
359 * the mount.
360 */
361 status = do_expire_wait(path, 0);
362 if (status && status != -EAGAIN)
363 return NULL;
364
365 /* Callback to the daemon to perform the mount or wait */
366 spin_lock(&sbi->fs_lock);
367 if (ino->flags & AUTOFS_INF_PENDING) {
368 spin_unlock(&sbi->fs_lock);
369 status = autofs_mount_wait(path, 0);
370 if (status)
371 return ERR_PTR(status);
372 goto done;
373 }
374
375 /*
376 * If the dentry is a symlink it's equivalent to a directory
377 * having path_is_mountpoint() true, so there's no need to call
378 * back to the daemon.
379 */
380 if (d_really_is_positive(dentry) && d_is_symlink(dentry)) {
381 spin_unlock(&sbi->fs_lock);
382 goto done;
383 }
384
385 if (!path_is_mountpoint(path)) {
386 /*
387 * It's possible that user space hasn't removed directories
388 * after umounting a rootless multi-mount, although it
389 * should. For v5 path_has_submounts() is sufficient to
390 * handle this because the leaves of the directory tree under
391 * the mount never trigger mounts themselves (they have an
392 * autofs trigger mount mounted on them). But v4 pseudo direct
393 * mounts do need the leaves to trigger mounts. In this case
394 * we have no choice but to use the autofs_empty() check and
395 * require user space behave.
396 */
397 if (sbi->version > 4) {
398 if (path_has_submounts(path)) {
399 spin_unlock(&sbi->fs_lock);
400 goto done;
401 }
402 } else {
403 if (!autofs_empty(ino)) {
404 spin_unlock(&sbi->fs_lock);
405 goto done;
406 }
407 }
408 ino->flags |= AUTOFS_INF_PENDING;
409 spin_unlock(&sbi->fs_lock);
410 status = autofs_mount_wait(path, 0);
411 spin_lock(&sbi->fs_lock);
412 ino->flags &= ~AUTOFS_INF_PENDING;
413 if (status) {
414 spin_unlock(&sbi->fs_lock);
415 return ERR_PTR(status);
416 }
417 }
418 spin_unlock(&sbi->fs_lock);
419done:
420 /* Mount succeeded, check if we ended up with a new dentry */
421 dentry = autofs_mountpoint_changed(path);
422 if (!dentry)
423 return ERR_PTR(-ENOENT);
424
425 return NULL;
426}
427
428static int autofs_d_manage(const struct path *path, bool rcu_walk)
429{
430 struct dentry *dentry = path->dentry;
431 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
432 struct autofs_info *ino = autofs_dentry_ino(dentry);
433 int status;
434
435 pr_debug("dentry=%p %pd\n", dentry, dentry);
436
437 /* The daemon never waits. */
438 if (autofs_oz_mode(sbi)) {
439 if (!path_is_mountpoint(path))
440 return -EISDIR;
441 return 0;
442 }
443
444 /* Wait for pending expires */
445 if (do_expire_wait(path, rcu_walk) == -ECHILD)
446 return -ECHILD;
447
448 /*
449 * This dentry may be under construction so wait on mount
450 * completion.
451 */
452 status = autofs_mount_wait(path, rcu_walk);
453 if (status)
454 return status;
455
456 if (rcu_walk) {
457 /* We don't need fs_lock in rcu_walk mode,
458 * just testing 'AUTOFS_INF_WANT_EXPIRE' is enough.
459 *
460 * We only return -EISDIR when certain this isn't
461 * a mount-trap.
462 */
463 struct inode *inode;
464
465 if (ino->flags & AUTOFS_INF_WANT_EXPIRE)
466 return 0;
467 if (path_is_mountpoint(path))
468 return 0;
469 inode = d_inode_rcu(dentry);
470 if (inode && S_ISLNK(inode->i_mode))
471 return -EISDIR;
472 if (!autofs_empty(ino))
473 return -EISDIR;
474 return 0;
475 }
476
477 spin_lock(&sbi->fs_lock);
478 /*
479 * If the dentry has been selected for expire while we slept
480 * on the lock then it might go away. We'll deal with that in
481 * ->d_automount() and wait on a new mount if the expire
482 * succeeds or return here if it doesn't (since there's no
483 * mount to follow with a rootless multi-mount).
484 */
485 if (!(ino->flags & AUTOFS_INF_EXPIRING)) {
486 /*
487 * Any needed mounting has been completed and the path
488 * updated so check if this is a rootless multi-mount so
489 * we can avoid needless calls ->d_automount() and avoid
490 * an incorrect ELOOP error return.
491 */
492 if ((!path_is_mountpoint(path) && !autofs_empty(ino)) ||
493 (d_really_is_positive(dentry) && d_is_symlink(dentry)))
494 status = -EISDIR;
495 }
496 spin_unlock(&sbi->fs_lock);
497
498 return status;
499}
500
501/* Lookups in the root directory */
502static struct dentry *autofs_lookup(struct inode *dir,
503 struct dentry *dentry, unsigned int flags)
504{
505 struct autofs_sb_info *sbi;
506 struct autofs_info *ino;
507 struct dentry *active;
508
509 pr_debug("name = %pd\n", dentry);
510
511 /* File name too long to exist */
512 if (dentry->d_name.len > NAME_MAX)
513 return ERR_PTR(-ENAMETOOLONG);
514
515 sbi = autofs_sbi(dir->i_sb);
516
517 pr_debug("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d\n",
518 current->pid, task_pgrp_nr(current),
519 sbi->flags & AUTOFS_SBI_CATATONIC,
520 autofs_oz_mode(sbi));
521
522 active = autofs_lookup_active(dentry);
523 if (active)
524 return active;
525 else {
526 /*
527 * A dentry that is not within the root can never trigger a
528 * mount operation, unless the directory already exists, so we
529 * can return fail immediately. The daemon however does need
530 * to create directories within the file system.
531 */
532 if (!autofs_oz_mode(sbi) && !IS_ROOT(dentry->d_parent))
533 return ERR_PTR(-ENOENT);
534
535 ino = autofs_new_ino(sbi);
536 if (!ino)
537 return ERR_PTR(-ENOMEM);
538
539 spin_lock(&sbi->lookup_lock);
540 spin_lock(&dentry->d_lock);
541 /* Mark entries in the root as mount triggers */
542 if (IS_ROOT(dentry->d_parent) &&
543 autofs_type_indirect(sbi->type))
544 __managed_dentry_set_managed(dentry);
545 dentry->d_fsdata = ino;
546 ino->dentry = dentry;
547
548 list_add(&ino->active, &sbi->active_list);
549 spin_unlock(&sbi->lookup_lock);
550 spin_unlock(&dentry->d_lock);
551 }
552 return NULL;
553}
554
555static int autofs_dir_permission(const struct mnt_idmap *idmap,
556 struct inode *inode, int mask)
557{
558 if (mask & MAY_WRITE) {
559 struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb);
560
561 if (!autofs_oz_mode(sbi))
562 return -EACCES;
563
564 /* autofs_oz_mode() needs to allow path walks when the
565 * autofs mount is catatonic but the state of an autofs
566 * file system needs to be preserved over restarts.
567 */
568 if (sbi->flags & AUTOFS_SBI_CATATONIC)
569 return -EACCES;
570 }
571
572 return generic_permission(idmap, inode, mask);
573}
574
575static int autofs_dir_symlink(const struct mnt_idmap *idmap,
576 struct inode *dir, struct dentry *dentry,
577 const char *symname)
578{
579 struct autofs_info *ino = autofs_dentry_ino(dentry);
580 struct autofs_info *p_ino;
581 struct inode *inode;
582 char *cp;
583
584 pr_debug("%s <- %pd\n", symname, dentry);
585
586 BUG_ON(!ino);
587
588 autofs_clean_ino(ino);
589
590 autofs_del_active(dentry);
591
592 cp = kstrdup(symname, GFP_KERNEL);
593 if (!cp)
594 return -ENOMEM;
595
596 inode = autofs_get_inode(dir->i_sb, S_IFLNK | 0555);
597 if (!inode) {
598 kfree(cp);
599 return -ENOMEM;
600 }
601 inode->i_private = cp;
602 inode->i_size = strlen(cp);
603
604 d_make_persistent(dentry, inode);
605 p_ino = autofs_dentry_ino(dentry->d_parent);
606 p_ino->count++;
607
608 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
609
610 return 0;
611}
612
613/*
614 * NOTE!
615 *
616 * Normal filesystems would do a "d_delete()" to tell the VFS dcache
617 * that the file no longer exists. However, doing that means that the
618 * VFS layer can turn the dentry into a negative dentry. We don't want
619 * this, because the unlink is probably the result of an expire.
620 * We simply d_drop it and add it to a expiring list in the super block,
621 * which allows the dentry lookup to check for an incomplete expire.
622 *
623 * If a process is blocked on the dentry waiting for the expire to finish,
624 * it will invalidate the dentry and try to mount with a new one.
625 *
626 * Also see autofs_dir_rmdir()..
627 */
628static int autofs_dir_unlink(struct inode *dir, struct dentry *dentry)
629{
630 struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
631 struct autofs_info *p_ino;
632
633 p_ino = autofs_dentry_ino(dentry->d_parent);
634 p_ino->count--;
635 d_make_discardable(dentry);
636
637 d_inode(dentry)->i_size = 0;
638 clear_nlink(d_inode(dentry));
639
640 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
641
642 spin_lock(&sbi->lookup_lock);
643 __autofs_add_expiring(dentry);
644 d_drop(dentry);
645 spin_unlock(&sbi->lookup_lock);
646
647 return 0;
648}
649
650/*
651 * Version 4 of autofs provides a pseudo direct mount implementation
652 * that relies on directories at the leaves of a directory tree under
653 * an indirect mount to trigger mounts. To allow for this we need to
654 * set the DMANAGED_AUTOMOUNT and DMANAGED_TRANSIT flags on the leaves
655 * of the directory tree. There is no need to clear the automount flag
656 * following a mount or restore it after an expire because these mounts
657 * are always covered. However, it is necessary to ensure that these
658 * flags are clear on non-empty directories to avoid unnecessary calls
659 * during path walks.
660 */
661static void autofs_set_leaf_automount_flags(struct dentry *dentry)
662{
663 struct dentry *parent;
664
665 /* root and dentrys in the root are already handled */
666 if (IS_ROOT(dentry->d_parent))
667 return;
668
669 managed_dentry_set_managed(dentry);
670
671 parent = dentry->d_parent;
672 /* only consider parents below dentrys in the root */
673 if (IS_ROOT(parent->d_parent))
674 return;
675 managed_dentry_clear_managed(parent);
676}
677
678static void autofs_clear_leaf_automount_flags(struct dentry *dentry)
679{
680 struct dentry *parent;
681
682 /* flags for dentrys in the root are handled elsewhere */
683 if (IS_ROOT(dentry->d_parent))
684 return;
685
686 managed_dentry_clear_managed(dentry);
687
688 parent = dentry->d_parent;
689 /* only consider parents below dentrys in the root */
690 if (IS_ROOT(parent->d_parent))
691 return;
692 if (autofs_dentry_ino(parent)->count == 2)
693 managed_dentry_set_managed(parent);
694}
695
696static int autofs_dir_rmdir(struct inode *dir, struct dentry *dentry)
697{
698 struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
699 struct autofs_info *ino = autofs_dentry_ino(dentry);
700 struct autofs_info *p_ino;
701
702 pr_debug("dentry %p, removing %pd\n", dentry, dentry);
703
704 if (ino->count != 1)
705 return -ENOTEMPTY;
706
707 spin_lock(&sbi->lookup_lock);
708 __autofs_add_expiring(dentry);
709 d_drop(dentry);
710 spin_unlock(&sbi->lookup_lock);
711
712 if (sbi->version < 5)
713 autofs_clear_leaf_automount_flags(dentry);
714
715 p_ino = autofs_dentry_ino(dentry->d_parent);
716 p_ino->count--;
717 d_make_discardable(dentry);
718 d_inode(dentry)->i_size = 0;
719 clear_nlink(d_inode(dentry));
720
721 if (dir->i_nlink)
722 drop_nlink(dir);
723
724 return 0;
725}
726
727static struct dentry *autofs_dir_mkdir(const struct mnt_idmap *idmap,
728 struct inode *dir, struct dentry *dentry,
729 umode_t mode)
730{
731 struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
732 struct autofs_info *ino = autofs_dentry_ino(dentry);
733 struct autofs_info *p_ino;
734 struct inode *inode;
735
736 pr_debug("dentry %p, creating %pd\n", dentry, dentry);
737
738 BUG_ON(!ino);
739
740 autofs_clean_ino(ino);
741
742 autofs_del_active(dentry);
743
744 inode = autofs_get_inode(dir->i_sb, mode);
745 if (!inode)
746 return ERR_PTR(-ENOMEM);
747
748 if (sbi->version < 5)
749 autofs_set_leaf_automount_flags(dentry);
750
751 d_make_persistent(dentry, inode);
752 p_ino = autofs_dentry_ino(dentry->d_parent);
753 p_ino->count++;
754 inc_nlink(dir);
755 inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
756
757 return NULL;
758}
759
760/* Get/set timeout ioctl() operation */
761#ifdef CONFIG_COMPAT
762static inline int autofs_compat_get_set_timeout(struct autofs_sb_info *sbi,
763 compat_ulong_t __user *p)
764{
765 unsigned long ntimeout;
766 int rv;
767
768 rv = get_user(ntimeout, p);
769 if (rv)
770 goto error;
771
772 rv = put_user(sbi->exp_timeout/HZ, p);
773 if (rv)
774 goto error;
775
776 if (ntimeout > UINT_MAX/HZ)
777 sbi->exp_timeout = 0;
778 else
779 sbi->exp_timeout = ntimeout * HZ;
780
781 return 0;
782error:
783 return rv;
784}
785#endif
786
787static inline int autofs_get_set_timeout(struct autofs_sb_info *sbi,
788 unsigned long __user *p)
789{
790 unsigned long ntimeout;
791 int rv;
792
793 rv = get_user(ntimeout, p);
794 if (rv)
795 goto error;
796
797 rv = put_user(sbi->exp_timeout/HZ, p);
798 if (rv)
799 goto error;
800
801 if (ntimeout > ULONG_MAX/HZ)
802 sbi->exp_timeout = 0;
803 else
804 sbi->exp_timeout = ntimeout * HZ;
805
806 return 0;
807error:
808 return rv;
809}
810
811/* Return protocol version */
812static inline int autofs_get_protover(struct autofs_sb_info *sbi,
813 int __user *p)
814{
815 return put_user(sbi->version, p);
816}
817
818/* Return protocol sub version */
819static inline int autofs_get_protosubver(struct autofs_sb_info *sbi,
820 int __user *p)
821{
822 return put_user(sbi->sub_version, p);
823}
824
825/*
826* Tells the daemon whether it can umount the autofs mount.
827*/
828static inline int autofs_ask_umount(struct vfsmount *mnt, int __user *p)
829{
830 int status = 0;
831
832 if (may_umount(mnt))
833 status = 1;
834
835 pr_debug("may umount %d\n", status);
836
837 status = put_user(status, p);
838
839 return status;
840}
841
842/* Identify autofs_dentries - this is so we can tell if there's
843 * an extra dentry refcount or not. We only hold a refcount on the
844 * dentry if its non-negative (ie, d_inode != NULL)
845 */
846int is_autofs_dentry(struct dentry *dentry)
847{
848 return dentry && d_really_is_positive(dentry) &&
849 dentry->d_op == &autofs_dentry_operations &&
850 dentry->d_fsdata != NULL;
851}
852
853/*
854 * ioctl()'s on the root directory is the chief method for the daemon to
855 * generate kernel reactions
856 */
857static int autofs_root_ioctl_unlocked(struct inode *inode, struct file *filp,
858 unsigned int cmd, unsigned long arg)
859{
860 struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb);
861 void __user *p = (void __user *)arg;
862
863 pr_debug("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u\n",
864 cmd, arg, sbi, task_pgrp_nr(current));
865
866 if (_IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
867 _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT)
868 return -ENOTTY;
869
870 if (!autofs_oz_mode(sbi) && !capable(CAP_SYS_ADMIN))
871 return -EPERM;
872
873 switch (cmd) {
874 case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */
875 return autofs_wait_release(sbi, (autofs_wqt_t) arg, 0);
876 case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */
877 return autofs_wait_release(sbi, (autofs_wqt_t) arg, -ENOENT);
878 case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
879 autofs_catatonic_mode(sbi);
880 return 0;
881 case AUTOFS_IOC_PROTOVER: /* Get protocol version */
882 return autofs_get_protover(sbi, p);
883 case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */
884 return autofs_get_protosubver(sbi, p);
885 case AUTOFS_IOC_SETTIMEOUT:
886 return autofs_get_set_timeout(sbi, p);
887#ifdef CONFIG_COMPAT
888 case AUTOFS_IOC_SETTIMEOUT32:
889 return autofs_compat_get_set_timeout(sbi, p);
890#endif
891
892 case AUTOFS_IOC_ASKUMOUNT:
893 return autofs_ask_umount(filp->f_path.mnt, p);
894
895 /* return a single thing to expire */
896 case AUTOFS_IOC_EXPIRE:
897 return autofs_expire_run(inode->i_sb, filp->f_path.mnt, sbi, p);
898 /* same as above, but can send multiple expires through pipe */
899 case AUTOFS_IOC_EXPIRE_MULTI:
900 return autofs_expire_multi(inode->i_sb,
901 filp->f_path.mnt, sbi, p);
902
903 default:
904 return -EINVAL;
905 }
906}
907
908static long autofs_root_ioctl(struct file *filp,
909 unsigned int cmd, unsigned long arg)
910{
911 struct inode *inode = file_inode(filp);
912
913 return autofs_root_ioctl_unlocked(inode, filp, cmd, arg);
914}
915
916#ifdef CONFIG_COMPAT
917static long autofs_root_compat_ioctl(struct file *filp,
918 unsigned int cmd, unsigned long arg)
919{
920 struct inode *inode = file_inode(filp);
921 int ret;
922
923 if (cmd == AUTOFS_IOC_READY || cmd == AUTOFS_IOC_FAIL)
924 ret = autofs_root_ioctl_unlocked(inode, filp, cmd, arg);
925 else
926 ret = autofs_root_ioctl_unlocked(inode, filp, cmd,
927 (unsigned long) compat_ptr(arg));
928
929 return ret;
930}
931#endif