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1/* -*- c -*- --------------------------------------------------------------- *
2 *
3 * linux/fs/autofs/root.c
4 *
5 * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
6 * Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org>
7 * Copyright 2001-2006 Ian Kent <raven@themaw.net>
8 *
9 * This file is part of the Linux kernel and is made available under
10 * the terms of the GNU General Public License, version 2, or at your
11 * option, any later version, incorporated herein by reference.
12 *
13 * ------------------------------------------------------------------------- */
14
15#include <linux/capability.h>
16#include <linux/errno.h>
17#include <linux/stat.h>
18#include <linux/slab.h>
19#include <linux/param.h>
20#include <linux/time.h>
21#include <linux/compat.h>
22#include <linux/mutex.h>
23
24#include "autofs_i.h"
25
26static int autofs4_dir_symlink(struct inode *,struct dentry *,const char *);
27static int autofs4_dir_unlink(struct inode *,struct dentry *);
28static int autofs4_dir_rmdir(struct inode *,struct dentry *);
29static int autofs4_dir_mkdir(struct inode *,struct dentry *,umode_t);
30static long autofs4_root_ioctl(struct file *,unsigned int,unsigned long);
31#ifdef CONFIG_COMPAT
32static long autofs4_root_compat_ioctl(struct file *,unsigned int,unsigned long);
33#endif
34static int autofs4_dir_open(struct inode *inode, struct file *file);
35static struct dentry *autofs4_lookup(struct inode *,struct dentry *, unsigned int);
36static struct vfsmount *autofs4_d_automount(struct path *);
37static int autofs4_d_manage(struct dentry *, bool);
38static void autofs4_dentry_release(struct dentry *);
39
40const struct file_operations autofs4_root_operations = {
41 .open = dcache_dir_open,
42 .release = dcache_dir_close,
43 .read = generic_read_dir,
44 .iterate = dcache_readdir,
45 .llseek = dcache_dir_lseek,
46 .unlocked_ioctl = autofs4_root_ioctl,
47#ifdef CONFIG_COMPAT
48 .compat_ioctl = autofs4_root_compat_ioctl,
49#endif
50};
51
52const struct file_operations autofs4_dir_operations = {
53 .open = autofs4_dir_open,
54 .release = dcache_dir_close,
55 .read = generic_read_dir,
56 .iterate = dcache_readdir,
57 .llseek = dcache_dir_lseek,
58};
59
60const struct inode_operations autofs4_dir_inode_operations = {
61 .lookup = autofs4_lookup,
62 .unlink = autofs4_dir_unlink,
63 .symlink = autofs4_dir_symlink,
64 .mkdir = autofs4_dir_mkdir,
65 .rmdir = autofs4_dir_rmdir,
66};
67
68const struct dentry_operations autofs4_dentry_operations = {
69 .d_automount = autofs4_d_automount,
70 .d_manage = autofs4_d_manage,
71 .d_release = autofs4_dentry_release,
72};
73
74static void autofs4_add_active(struct dentry *dentry)
75{
76 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
77 struct autofs_info *ino = autofs4_dentry_ino(dentry);
78 if (ino) {
79 spin_lock(&sbi->lookup_lock);
80 if (!ino->active_count) {
81 if (list_empty(&ino->active))
82 list_add(&ino->active, &sbi->active_list);
83 }
84 ino->active_count++;
85 spin_unlock(&sbi->lookup_lock);
86 }
87 return;
88}
89
90static void autofs4_del_active(struct dentry *dentry)
91{
92 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
93 struct autofs_info *ino = autofs4_dentry_ino(dentry);
94 if (ino) {
95 spin_lock(&sbi->lookup_lock);
96 ino->active_count--;
97 if (!ino->active_count) {
98 if (!list_empty(&ino->active))
99 list_del_init(&ino->active);
100 }
101 spin_unlock(&sbi->lookup_lock);
102 }
103 return;
104}
105
106static int autofs4_dir_open(struct inode *inode, struct file *file)
107{
108 struct dentry *dentry = file->f_path.dentry;
109 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
110
111 DPRINTK("file=%p dentry=%p %.*s",
112 file, dentry, dentry->d_name.len, dentry->d_name.name);
113
114 if (autofs4_oz_mode(sbi))
115 goto out;
116
117 /*
118 * An empty directory in an autofs file system is always a
119 * mount point. The daemon must have failed to mount this
120 * during lookup so it doesn't exist. This can happen, for
121 * example, if user space returns an incorrect status for a
122 * mount request. Otherwise we're doing a readdir on the
123 * autofs file system so just let the libfs routines handle
124 * it.
125 */
126 spin_lock(&sbi->lookup_lock);
127 if (!d_mountpoint(dentry) && simple_empty(dentry)) {
128 spin_unlock(&sbi->lookup_lock);
129 return -ENOENT;
130 }
131 spin_unlock(&sbi->lookup_lock);
132
133out:
134 return dcache_dir_open(inode, file);
135}
136
137static void autofs4_dentry_release(struct dentry *de)
138{
139 struct autofs_info *ino = autofs4_dentry_ino(de);
140 struct autofs_sb_info *sbi = autofs4_sbi(de->d_sb);
141
142 DPRINTK("releasing %p", de);
143
144 if (!ino)
145 return;
146
147 if (sbi) {
148 spin_lock(&sbi->lookup_lock);
149 if (!list_empty(&ino->active))
150 list_del(&ino->active);
151 if (!list_empty(&ino->expiring))
152 list_del(&ino->expiring);
153 spin_unlock(&sbi->lookup_lock);
154 }
155
156 autofs4_free_ino(ino);
157}
158
159static struct dentry *autofs4_lookup_active(struct dentry *dentry)
160{
161 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
162 struct dentry *parent = dentry->d_parent;
163 struct qstr *name = &dentry->d_name;
164 unsigned int len = name->len;
165 unsigned int hash = name->hash;
166 const unsigned char *str = name->name;
167 struct list_head *p, *head;
168
169 spin_lock(&sbi->lookup_lock);
170 head = &sbi->active_list;
171 list_for_each(p, head) {
172 struct autofs_info *ino;
173 struct dentry *active;
174 struct qstr *qstr;
175
176 ino = list_entry(p, struct autofs_info, active);
177 active = ino->dentry;
178
179 spin_lock(&active->d_lock);
180
181 /* Already gone? */
182 if ((int) d_count(active) <= 0)
183 goto next;
184
185 qstr = &active->d_name;
186
187 if (active->d_name.hash != hash)
188 goto next;
189 if (active->d_parent != parent)
190 goto next;
191
192 if (qstr->len != len)
193 goto next;
194 if (memcmp(qstr->name, str, len))
195 goto next;
196
197 if (d_unhashed(active)) {
198 dget_dlock(active);
199 spin_unlock(&active->d_lock);
200 spin_unlock(&sbi->lookup_lock);
201 return active;
202 }
203next:
204 spin_unlock(&active->d_lock);
205 }
206 spin_unlock(&sbi->lookup_lock);
207
208 return NULL;
209}
210
211static struct dentry *autofs4_lookup_expiring(struct dentry *dentry)
212{
213 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
214 struct dentry *parent = dentry->d_parent;
215 struct qstr *name = &dentry->d_name;
216 unsigned int len = name->len;
217 unsigned int hash = name->hash;
218 const unsigned char *str = name->name;
219 struct list_head *p, *head;
220
221 spin_lock(&sbi->lookup_lock);
222 head = &sbi->expiring_list;
223 list_for_each(p, head) {
224 struct autofs_info *ino;
225 struct dentry *expiring;
226 struct qstr *qstr;
227
228 ino = list_entry(p, struct autofs_info, expiring);
229 expiring = ino->dentry;
230
231 spin_lock(&expiring->d_lock);
232
233 /* We've already been dentry_iput or unlinked */
234 if (!expiring->d_inode)
235 goto next;
236
237 qstr = &expiring->d_name;
238
239 if (expiring->d_name.hash != hash)
240 goto next;
241 if (expiring->d_parent != parent)
242 goto next;
243
244 if (qstr->len != len)
245 goto next;
246 if (memcmp(qstr->name, str, len))
247 goto next;
248
249 if (d_unhashed(expiring)) {
250 dget_dlock(expiring);
251 spin_unlock(&expiring->d_lock);
252 spin_unlock(&sbi->lookup_lock);
253 return expiring;
254 }
255next:
256 spin_unlock(&expiring->d_lock);
257 }
258 spin_unlock(&sbi->lookup_lock);
259
260 return NULL;
261}
262
263static int autofs4_mount_wait(struct dentry *dentry)
264{
265 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
266 struct autofs_info *ino = autofs4_dentry_ino(dentry);
267 int status = 0;
268
269 if (ino->flags & AUTOFS_INF_PENDING) {
270 DPRINTK("waiting for mount name=%.*s",
271 dentry->d_name.len, dentry->d_name.name);
272 status = autofs4_wait(sbi, dentry, NFY_MOUNT);
273 DPRINTK("mount wait done status=%d", status);
274 }
275 ino->last_used = jiffies;
276 return status;
277}
278
279static int do_expire_wait(struct dentry *dentry)
280{
281 struct dentry *expiring;
282
283 expiring = autofs4_lookup_expiring(dentry);
284 if (!expiring)
285 return autofs4_expire_wait(dentry);
286 else {
287 /*
288 * If we are racing with expire the request might not
289 * be quite complete, but the directory has been removed
290 * so it must have been successful, just wait for it.
291 */
292 autofs4_expire_wait(expiring);
293 autofs4_del_expiring(expiring);
294 dput(expiring);
295 }
296 return 0;
297}
298
299static struct dentry *autofs4_mountpoint_changed(struct path *path)
300{
301 struct dentry *dentry = path->dentry;
302 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
303
304 /*
305 * If this is an indirect mount the dentry could have gone away
306 * as a result of an expire and a new one created.
307 */
308 if (autofs_type_indirect(sbi->type) && d_unhashed(dentry)) {
309 struct dentry *parent = dentry->d_parent;
310 struct autofs_info *ino;
311 struct dentry *new = d_lookup(parent, &dentry->d_name);
312 if (!new)
313 return NULL;
314 ino = autofs4_dentry_ino(new);
315 ino->last_used = jiffies;
316 dput(path->dentry);
317 path->dentry = new;
318 }
319 return path->dentry;
320}
321
322static struct vfsmount *autofs4_d_automount(struct path *path)
323{
324 struct dentry *dentry = path->dentry;
325 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
326 struct autofs_info *ino = autofs4_dentry_ino(dentry);
327 int status;
328
329 DPRINTK("dentry=%p %.*s",
330 dentry, dentry->d_name.len, dentry->d_name.name);
331
332 /* The daemon never triggers a mount. */
333 if (autofs4_oz_mode(sbi))
334 return NULL;
335
336 /*
337 * If an expire request is pending everyone must wait.
338 * If the expire fails we're still mounted so continue
339 * the follow and return. A return of -EAGAIN (which only
340 * happens with indirect mounts) means the expire completed
341 * and the directory was removed, so just go ahead and try
342 * the mount.
343 */
344 status = do_expire_wait(dentry);
345 if (status && status != -EAGAIN)
346 return NULL;
347
348 /* Callback to the daemon to perform the mount or wait */
349 spin_lock(&sbi->fs_lock);
350 if (ino->flags & AUTOFS_INF_PENDING) {
351 spin_unlock(&sbi->fs_lock);
352 status = autofs4_mount_wait(dentry);
353 if (status)
354 return ERR_PTR(status);
355 goto done;
356 }
357
358 /*
359 * If the dentry is a symlink it's equivalent to a directory
360 * having d_mountpoint() true, so there's no need to call back
361 * to the daemon.
362 */
363 if (dentry->d_inode && S_ISLNK(dentry->d_inode->i_mode)) {
364 spin_unlock(&sbi->fs_lock);
365 goto done;
366 }
367
368 if (!d_mountpoint(dentry)) {
369 /*
370 * It's possible that user space hasn't removed directories
371 * after umounting a rootless multi-mount, although it
372 * should. For v5 have_submounts() is sufficient to handle
373 * this because the leaves of the directory tree under the
374 * mount never trigger mounts themselves (they have an autofs
375 * trigger mount mounted on them). But v4 pseudo direct mounts
376 * do need the leaves to to trigger mounts. In this case we
377 * have no choice but to use the list_empty() check and
378 * require user space behave.
379 */
380 if (sbi->version > 4) {
381 if (have_submounts(dentry)) {
382 spin_unlock(&sbi->fs_lock);
383 goto done;
384 }
385 } else {
386 if (!simple_empty(dentry)) {
387 spin_unlock(&sbi->fs_lock);
388 goto done;
389 }
390 }
391 ino->flags |= AUTOFS_INF_PENDING;
392 spin_unlock(&sbi->fs_lock);
393 status = autofs4_mount_wait(dentry);
394 spin_lock(&sbi->fs_lock);
395 ino->flags &= ~AUTOFS_INF_PENDING;
396 if (status) {
397 spin_unlock(&sbi->fs_lock);
398 return ERR_PTR(status);
399 }
400 }
401 spin_unlock(&sbi->fs_lock);
402done:
403 /* Mount succeeded, check if we ended up with a new dentry */
404 dentry = autofs4_mountpoint_changed(path);
405 if (!dentry)
406 return ERR_PTR(-ENOENT);
407
408 return NULL;
409}
410
411static int autofs4_d_manage(struct dentry *dentry, bool rcu_walk)
412{
413 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
414 struct autofs_info *ino = autofs4_dentry_ino(dentry);
415 int status;
416
417 DPRINTK("dentry=%p %.*s",
418 dentry, dentry->d_name.len, dentry->d_name.name);
419
420 /* The daemon never waits. */
421 if (autofs4_oz_mode(sbi)) {
422 if (rcu_walk)
423 return 0;
424 if (!d_mountpoint(dentry))
425 return -EISDIR;
426 return 0;
427 }
428
429 /* We need to sleep, so we need pathwalk to be in ref-mode */
430 if (rcu_walk)
431 return -ECHILD;
432
433 /* Wait for pending expires */
434 do_expire_wait(dentry);
435
436 /*
437 * This dentry may be under construction so wait on mount
438 * completion.
439 */
440 status = autofs4_mount_wait(dentry);
441 if (status)
442 return status;
443
444 spin_lock(&sbi->fs_lock);
445 /*
446 * If the dentry has been selected for expire while we slept
447 * on the lock then it might go away. We'll deal with that in
448 * ->d_automount() and wait on a new mount if the expire
449 * succeeds or return here if it doesn't (since there's no
450 * mount to follow with a rootless multi-mount).
451 */
452 if (!(ino->flags & AUTOFS_INF_EXPIRING)) {
453 /*
454 * Any needed mounting has been completed and the path
455 * updated so check if this is a rootless multi-mount so
456 * we can avoid needless calls ->d_automount() and avoid
457 * an incorrect ELOOP error return.
458 */
459 if ((!d_mountpoint(dentry) && !simple_empty(dentry)) ||
460 (dentry->d_inode && S_ISLNK(dentry->d_inode->i_mode)))
461 status = -EISDIR;
462 }
463 spin_unlock(&sbi->fs_lock);
464
465 return status;
466}
467
468/* Lookups in the root directory */
469static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
470{
471 struct autofs_sb_info *sbi;
472 struct autofs_info *ino;
473 struct dentry *active;
474
475 DPRINTK("name = %.*s", dentry->d_name.len, dentry->d_name.name);
476
477 /* File name too long to exist */
478 if (dentry->d_name.len > NAME_MAX)
479 return ERR_PTR(-ENAMETOOLONG);
480
481 sbi = autofs4_sbi(dir->i_sb);
482
483 DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
484 current->pid, task_pgrp_nr(current), sbi->catatonic,
485 autofs4_oz_mode(sbi));
486
487 active = autofs4_lookup_active(dentry);
488 if (active) {
489 return active;
490 } else {
491 /*
492 * A dentry that is not within the root can never trigger a
493 * mount operation, unless the directory already exists, so we
494 * can return fail immediately. The daemon however does need
495 * to create directories within the file system.
496 */
497 if (!autofs4_oz_mode(sbi) && !IS_ROOT(dentry->d_parent))
498 return ERR_PTR(-ENOENT);
499
500 /* Mark entries in the root as mount triggers */
501 if (autofs_type_indirect(sbi->type) && IS_ROOT(dentry->d_parent))
502 __managed_dentry_set_managed(dentry);
503
504 ino = autofs4_new_ino(sbi);
505 if (!ino)
506 return ERR_PTR(-ENOMEM);
507
508 dentry->d_fsdata = ino;
509 ino->dentry = dentry;
510
511 autofs4_add_active(dentry);
512
513 d_instantiate(dentry, NULL);
514 }
515 return NULL;
516}
517
518static int autofs4_dir_symlink(struct inode *dir,
519 struct dentry *dentry,
520 const char *symname)
521{
522 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
523 struct autofs_info *ino = autofs4_dentry_ino(dentry);
524 struct autofs_info *p_ino;
525 struct inode *inode;
526 size_t size = strlen(symname);
527 char *cp;
528
529 DPRINTK("%s <- %.*s", symname,
530 dentry->d_name.len, dentry->d_name.name);
531
532 if (!autofs4_oz_mode(sbi))
533 return -EACCES;
534
535 BUG_ON(!ino);
536
537 autofs4_clean_ino(ino);
538
539 autofs4_del_active(dentry);
540
541 cp = kmalloc(size + 1, GFP_KERNEL);
542 if (!cp)
543 return -ENOMEM;
544
545 strcpy(cp, symname);
546
547 inode = autofs4_get_inode(dir->i_sb, S_IFLNK | 0555);
548 if (!inode) {
549 kfree(cp);
550 if (!dentry->d_fsdata)
551 kfree(ino);
552 return -ENOMEM;
553 }
554 inode->i_private = cp;
555 inode->i_size = size;
556 d_add(dentry, inode);
557
558 dget(dentry);
559 atomic_inc(&ino->count);
560 p_ino = autofs4_dentry_ino(dentry->d_parent);
561 if (p_ino && !IS_ROOT(dentry))
562 atomic_inc(&p_ino->count);
563
564 dir->i_mtime = CURRENT_TIME;
565
566 return 0;
567}
568
569/*
570 * NOTE!
571 *
572 * Normal filesystems would do a "d_delete()" to tell the VFS dcache
573 * that the file no longer exists. However, doing that means that the
574 * VFS layer can turn the dentry into a negative dentry. We don't want
575 * this, because the unlink is probably the result of an expire.
576 * We simply d_drop it and add it to a expiring list in the super block,
577 * which allows the dentry lookup to check for an incomplete expire.
578 *
579 * If a process is blocked on the dentry waiting for the expire to finish,
580 * it will invalidate the dentry and try to mount with a new one.
581 *
582 * Also see autofs4_dir_rmdir()..
583 */
584static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
585{
586 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
587 struct autofs_info *ino = autofs4_dentry_ino(dentry);
588 struct autofs_info *p_ino;
589
590 /* This allows root to remove symlinks */
591 if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN))
592 return -EPERM;
593
594 if (atomic_dec_and_test(&ino->count)) {
595 p_ino = autofs4_dentry_ino(dentry->d_parent);
596 if (p_ino && !IS_ROOT(dentry))
597 atomic_dec(&p_ino->count);
598 }
599 dput(ino->dentry);
600
601 dentry->d_inode->i_size = 0;
602 clear_nlink(dentry->d_inode);
603
604 dir->i_mtime = CURRENT_TIME;
605
606 spin_lock(&sbi->lookup_lock);
607 __autofs4_add_expiring(dentry);
608 d_drop(dentry);
609 spin_unlock(&sbi->lookup_lock);
610
611 return 0;
612}
613
614/*
615 * Version 4 of autofs provides a pseudo direct mount implementation
616 * that relies on directories at the leaves of a directory tree under
617 * an indirect mount to trigger mounts. To allow for this we need to
618 * set the DMANAGED_AUTOMOUNT and DMANAGED_TRANSIT flags on the leaves
619 * of the directory tree. There is no need to clear the automount flag
620 * following a mount or restore it after an expire because these mounts
621 * are always covered. However, it is necessary to ensure that these
622 * flags are clear on non-empty directories to avoid unnecessary calls
623 * during path walks.
624 */
625static void autofs_set_leaf_automount_flags(struct dentry *dentry)
626{
627 struct dentry *parent;
628
629 /* root and dentrys in the root are already handled */
630 if (IS_ROOT(dentry->d_parent))
631 return;
632
633 managed_dentry_set_managed(dentry);
634
635 parent = dentry->d_parent;
636 /* only consider parents below dentrys in the root */
637 if (IS_ROOT(parent->d_parent))
638 return;
639 managed_dentry_clear_managed(parent);
640 return;
641}
642
643static void autofs_clear_leaf_automount_flags(struct dentry *dentry)
644{
645 struct list_head *d_child;
646 struct dentry *parent;
647
648 /* flags for dentrys in the root are handled elsewhere */
649 if (IS_ROOT(dentry->d_parent))
650 return;
651
652 managed_dentry_clear_managed(dentry);
653
654 parent = dentry->d_parent;
655 /* only consider parents below dentrys in the root */
656 if (IS_ROOT(parent->d_parent))
657 return;
658 d_child = &dentry->d_u.d_child;
659 /* Set parent managed if it's becoming empty */
660 if (d_child->next == &parent->d_subdirs &&
661 d_child->prev == &parent->d_subdirs)
662 managed_dentry_set_managed(parent);
663 return;
664}
665
666static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
667{
668 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
669 struct autofs_info *ino = autofs4_dentry_ino(dentry);
670 struct autofs_info *p_ino;
671
672 DPRINTK("dentry %p, removing %.*s",
673 dentry, dentry->d_name.len, dentry->d_name.name);
674
675 if (!autofs4_oz_mode(sbi))
676 return -EACCES;
677
678 spin_lock(&sbi->lookup_lock);
679 if (!simple_empty(dentry)) {
680 spin_unlock(&sbi->lookup_lock);
681 return -ENOTEMPTY;
682 }
683 __autofs4_add_expiring(dentry);
684 d_drop(dentry);
685 spin_unlock(&sbi->lookup_lock);
686
687 if (sbi->version < 5)
688 autofs_clear_leaf_automount_flags(dentry);
689
690 if (atomic_dec_and_test(&ino->count)) {
691 p_ino = autofs4_dentry_ino(dentry->d_parent);
692 if (p_ino && dentry->d_parent != dentry)
693 atomic_dec(&p_ino->count);
694 }
695 dput(ino->dentry);
696 dentry->d_inode->i_size = 0;
697 clear_nlink(dentry->d_inode);
698
699 if (dir->i_nlink)
700 drop_nlink(dir);
701
702 return 0;
703}
704
705static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
706{
707 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
708 struct autofs_info *ino = autofs4_dentry_ino(dentry);
709 struct autofs_info *p_ino;
710 struct inode *inode;
711
712 if (!autofs4_oz_mode(sbi))
713 return -EACCES;
714
715 DPRINTK("dentry %p, creating %.*s",
716 dentry, dentry->d_name.len, dentry->d_name.name);
717
718 BUG_ON(!ino);
719
720 autofs4_clean_ino(ino);
721
722 autofs4_del_active(dentry);
723
724 inode = autofs4_get_inode(dir->i_sb, S_IFDIR | 0555);
725 if (!inode)
726 return -ENOMEM;
727 d_add(dentry, inode);
728
729 if (sbi->version < 5)
730 autofs_set_leaf_automount_flags(dentry);
731
732 dget(dentry);
733 atomic_inc(&ino->count);
734 p_ino = autofs4_dentry_ino(dentry->d_parent);
735 if (p_ino && !IS_ROOT(dentry))
736 atomic_inc(&p_ino->count);
737 inc_nlink(dir);
738 dir->i_mtime = CURRENT_TIME;
739
740 return 0;
741}
742
743/* Get/set timeout ioctl() operation */
744#ifdef CONFIG_COMPAT
745static inline int autofs4_compat_get_set_timeout(struct autofs_sb_info *sbi,
746 compat_ulong_t __user *p)
747{
748 int rv;
749 unsigned long ntimeout;
750
751 if ((rv = get_user(ntimeout, p)) ||
752 (rv = put_user(sbi->exp_timeout/HZ, p)))
753 return rv;
754
755 if (ntimeout > UINT_MAX/HZ)
756 sbi->exp_timeout = 0;
757 else
758 sbi->exp_timeout = ntimeout * HZ;
759
760 return 0;
761}
762#endif
763
764static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi,
765 unsigned long __user *p)
766{
767 int rv;
768 unsigned long ntimeout;
769
770 if ((rv = get_user(ntimeout, p)) ||
771 (rv = put_user(sbi->exp_timeout/HZ, p)))
772 return rv;
773
774 if (ntimeout > ULONG_MAX/HZ)
775 sbi->exp_timeout = 0;
776 else
777 sbi->exp_timeout = ntimeout * HZ;
778
779 return 0;
780}
781
782/* Return protocol version */
783static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int __user *p)
784{
785 return put_user(sbi->version, p);
786}
787
788/* Return protocol sub version */
789static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p)
790{
791 return put_user(sbi->sub_version, p);
792}
793
794/*
795* Tells the daemon whether it can umount the autofs mount.
796*/
797static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p)
798{
799 int status = 0;
800
801 if (may_umount(mnt))
802 status = 1;
803
804 DPRINTK("returning %d", status);
805
806 status = put_user(status, p);
807
808 return status;
809}
810
811/* Identify autofs4_dentries - this is so we can tell if there's
812 an extra dentry refcount or not. We only hold a refcount on the
813 dentry if its non-negative (ie, d_inode != NULL)
814*/
815int is_autofs4_dentry(struct dentry *dentry)
816{
817 return dentry && dentry->d_inode &&
818 dentry->d_op == &autofs4_dentry_operations &&
819 dentry->d_fsdata != NULL;
820}
821
822/*
823 * ioctl()'s on the root directory is the chief method for the daemon to
824 * generate kernel reactions
825 */
826static int autofs4_root_ioctl_unlocked(struct inode *inode, struct file *filp,
827 unsigned int cmd, unsigned long arg)
828{
829 struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb);
830 void __user *p = (void __user *)arg;
831
832 DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u",
833 cmd,arg,sbi,task_pgrp_nr(current));
834
835 if (_IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
836 _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT)
837 return -ENOTTY;
838
839 if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN))
840 return -EPERM;
841
842 switch(cmd) {
843 case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */
844 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0);
845 case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */
846 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
847 case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
848 autofs4_catatonic_mode(sbi);
849 return 0;
850 case AUTOFS_IOC_PROTOVER: /* Get protocol version */
851 return autofs4_get_protover(sbi, p);
852 case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */
853 return autofs4_get_protosubver(sbi, p);
854 case AUTOFS_IOC_SETTIMEOUT:
855 return autofs4_get_set_timeout(sbi, p);
856#ifdef CONFIG_COMPAT
857 case AUTOFS_IOC_SETTIMEOUT32:
858 return autofs4_compat_get_set_timeout(sbi, p);
859#endif
860
861 case AUTOFS_IOC_ASKUMOUNT:
862 return autofs4_ask_umount(filp->f_path.mnt, p);
863
864 /* return a single thing to expire */
865 case AUTOFS_IOC_EXPIRE:
866 return autofs4_expire_run(inode->i_sb,filp->f_path.mnt,sbi, p);
867 /* same as above, but can send multiple expires through pipe */
868 case AUTOFS_IOC_EXPIRE_MULTI:
869 return autofs4_expire_multi(inode->i_sb,filp->f_path.mnt,sbi, p);
870
871 default:
872 return -ENOSYS;
873 }
874}
875
876static long autofs4_root_ioctl(struct file *filp,
877 unsigned int cmd, unsigned long arg)
878{
879 struct inode *inode = file_inode(filp);
880 return autofs4_root_ioctl_unlocked(inode, filp, cmd, arg);
881}
882
883#ifdef CONFIG_COMPAT
884static long autofs4_root_compat_ioctl(struct file *filp,
885 unsigned int cmd, unsigned long arg)
886{
887 struct inode *inode = file_inode(filp);
888 int ret;
889
890 if (cmd == AUTOFS_IOC_READY || cmd == AUTOFS_IOC_FAIL)
891 ret = autofs4_root_ioctl_unlocked(inode, filp, cmd, arg);
892 else
893 ret = autofs4_root_ioctl_unlocked(inode, filp, cmd,
894 (unsigned long)compat_ptr(arg));
895
896 return ret;
897}
898#endif