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
26 static int autofs4_dir_symlink(struct inode *,struct dentry *,const char *);
27 static int autofs4_dir_unlink(struct inode *,struct dentry *);
28 static int autofs4_dir_rmdir(struct inode *,struct dentry *);
29 static int autofs4_dir_mkdir(struct inode *,struct dentry *,umode_t);
30 static long autofs4_root_ioctl(struct file *,unsigned int,unsigned long);
31 #ifdef CONFIG_COMPAT
32 static long autofs4_root_compat_ioctl(struct file *,unsigned int,unsigned long);
33 #endif
34 static int autofs4_dir_open(struct inode *inode, struct file *file);
35 static struct dentry *autofs4_lookup(struct inode *,struct dentry *, unsigned int);
36 static struct vfsmount *autofs4_d_automount(struct path *);
37 static int autofs4_d_manage(struct dentry *, bool);
38 static void autofs4_dentry_release(struct dentry *);
39
40 const 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
52 const 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
60 const 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
68 const 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
autofs4_add_active(struct dentry * dentry)74 static 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
autofs4_del_active(struct dentry * dentry)90 static 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
autofs4_dir_open(struct inode * inode,struct file * file)106 static 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
133 out:
134 return dcache_dir_open(inode, file);
135 }
136
autofs4_dentry_release(struct dentry * de)137 static 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
autofs4_lookup_active(struct dentry * dentry)159 static 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 head = &sbi->active_list;
170 if (list_empty(head))
171 return NULL;
172 spin_lock(&sbi->lookup_lock);
173 list_for_each(p, head) {
174 struct autofs_info *ino;
175 struct dentry *active;
176 struct qstr *qstr;
177
178 ino = list_entry(p, struct autofs_info, active);
179 active = ino->dentry;
180
181 spin_lock(&active->d_lock);
182
183 /* Already gone? */
184 if ((int) d_count(active) <= 0)
185 goto next;
186
187 qstr = &active->d_name;
188
189 if (active->d_name.hash != hash)
190 goto next;
191 if (active->d_parent != parent)
192 goto next;
193
194 if (qstr->len != len)
195 goto next;
196 if (memcmp(qstr->name, str, len))
197 goto next;
198
199 if (d_unhashed(active)) {
200 dget_dlock(active);
201 spin_unlock(&active->d_lock);
202 spin_unlock(&sbi->lookup_lock);
203 return active;
204 }
205 next:
206 spin_unlock(&active->d_lock);
207 }
208 spin_unlock(&sbi->lookup_lock);
209
210 return NULL;
211 }
212
autofs4_lookup_expiring(struct dentry * dentry,bool rcu_walk)213 static struct dentry *autofs4_lookup_expiring(struct dentry *dentry,
214 bool rcu_walk)
215 {
216 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
217 struct dentry *parent = dentry->d_parent;
218 struct qstr *name = &dentry->d_name;
219 unsigned int len = name->len;
220 unsigned int hash = name->hash;
221 const unsigned char *str = name->name;
222 struct list_head *p, *head;
223
224 head = &sbi->expiring_list;
225 if (list_empty(head))
226 return NULL;
227 spin_lock(&sbi->lookup_lock);
228 list_for_each(p, head) {
229 struct autofs_info *ino;
230 struct dentry *expiring;
231 struct qstr *qstr;
232
233 if (rcu_walk) {
234 spin_unlock(&sbi->lookup_lock);
235 return ERR_PTR(-ECHILD);
236 }
237
238 ino = list_entry(p, struct autofs_info, expiring);
239 expiring = ino->dentry;
240
241 spin_lock(&expiring->d_lock);
242
243 /* We've already been dentry_iput or unlinked */
244 if (!expiring->d_inode)
245 goto next;
246
247 qstr = &expiring->d_name;
248
249 if (expiring->d_name.hash != hash)
250 goto next;
251 if (expiring->d_parent != parent)
252 goto next;
253
254 if (qstr->len != len)
255 goto next;
256 if (memcmp(qstr->name, str, len))
257 goto next;
258
259 if (d_unhashed(expiring)) {
260 dget_dlock(expiring);
261 spin_unlock(&expiring->d_lock);
262 spin_unlock(&sbi->lookup_lock);
263 return expiring;
264 }
265 next:
266 spin_unlock(&expiring->d_lock);
267 }
268 spin_unlock(&sbi->lookup_lock);
269
270 return NULL;
271 }
272
autofs4_mount_wait(struct dentry * dentry,bool rcu_walk)273 static int autofs4_mount_wait(struct dentry *dentry, bool rcu_walk)
274 {
275 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
276 struct autofs_info *ino = autofs4_dentry_ino(dentry);
277 int status = 0;
278
279 if (ino->flags & AUTOFS_INF_PENDING) {
280 if (rcu_walk)
281 return -ECHILD;
282 DPRINTK("waiting for mount name=%.*s",
283 dentry->d_name.len, dentry->d_name.name);
284 status = autofs4_wait(sbi, dentry, NFY_MOUNT);
285 DPRINTK("mount wait done status=%d", status);
286 }
287 ino->last_used = jiffies;
288 return status;
289 }
290
do_expire_wait(struct dentry * dentry,bool rcu_walk)291 static int do_expire_wait(struct dentry *dentry, bool rcu_walk)
292 {
293 struct dentry *expiring;
294
295 expiring = autofs4_lookup_expiring(dentry, rcu_walk);
296 if (IS_ERR(expiring))
297 return PTR_ERR(expiring);
298 if (!expiring)
299 return autofs4_expire_wait(dentry, rcu_walk);
300 else {
301 /*
302 * If we are racing with expire the request might not
303 * be quite complete, but the directory has been removed
304 * so it must have been successful, just wait for it.
305 */
306 autofs4_expire_wait(expiring, 0);
307 autofs4_del_expiring(expiring);
308 dput(expiring);
309 }
310 return 0;
311 }
312
autofs4_mountpoint_changed(struct path * path)313 static struct dentry *autofs4_mountpoint_changed(struct path *path)
314 {
315 struct dentry *dentry = path->dentry;
316 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
317
318 /*
319 * If this is an indirect mount the dentry could have gone away
320 * as a result of an expire and a new one created.
321 */
322 if (autofs_type_indirect(sbi->type) && d_unhashed(dentry)) {
323 struct dentry *parent = dentry->d_parent;
324 struct autofs_info *ino;
325 struct dentry *new = d_lookup(parent, &dentry->d_name);
326 if (!new)
327 return NULL;
328 ino = autofs4_dentry_ino(new);
329 ino->last_used = jiffies;
330 dput(path->dentry);
331 path->dentry = new;
332 }
333 return path->dentry;
334 }
335
autofs4_d_automount(struct path * path)336 static struct vfsmount *autofs4_d_automount(struct path *path)
337 {
338 struct dentry *dentry = path->dentry;
339 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
340 struct autofs_info *ino = autofs4_dentry_ino(dentry);
341 int status;
342
343 DPRINTK("dentry=%p %.*s",
344 dentry, dentry->d_name.len, dentry->d_name.name);
345
346 /* The daemon never triggers a mount. */
347 if (autofs4_oz_mode(sbi))
348 return NULL;
349
350 /*
351 * If an expire request is pending everyone must wait.
352 * If the expire fails we're still mounted so continue
353 * the follow and return. A return of -EAGAIN (which only
354 * happens with indirect mounts) means the expire completed
355 * and the directory was removed, so just go ahead and try
356 * the mount.
357 */
358 status = do_expire_wait(dentry, 0);
359 if (status && status != -EAGAIN)
360 return NULL;
361
362 /* Callback to the daemon to perform the mount or wait */
363 spin_lock(&sbi->fs_lock);
364 if (ino->flags & AUTOFS_INF_PENDING) {
365 spin_unlock(&sbi->fs_lock);
366 status = autofs4_mount_wait(dentry, 0);
367 if (status)
368 return ERR_PTR(status);
369 goto done;
370 }
371
372 /*
373 * If the dentry is a symlink it's equivalent to a directory
374 * having d_mountpoint() true, so there's no need to call back
375 * to the daemon.
376 */
377 if (dentry->d_inode && S_ISLNK(dentry->d_inode->i_mode)) {
378 spin_unlock(&sbi->fs_lock);
379 goto done;
380 }
381
382 if (!d_mountpoint(dentry)) {
383 /*
384 * It's possible that user space hasn't removed directories
385 * after umounting a rootless multi-mount, although it
386 * should. For v5 have_submounts() is sufficient to handle
387 * this because the leaves of the directory tree under the
388 * mount never trigger mounts themselves (they have an autofs
389 * trigger mount mounted on them). But v4 pseudo direct mounts
390 * do need the leaves to trigger mounts. In this case we
391 * have no choice but to use the list_empty() check and
392 * require user space behave.
393 */
394 if (sbi->version > 4) {
395 if (have_submounts(dentry)) {
396 spin_unlock(&sbi->fs_lock);
397 goto done;
398 }
399 } else {
400 if (!simple_empty(dentry)) {
401 spin_unlock(&sbi->fs_lock);
402 goto done;
403 }
404 }
405 ino->flags |= AUTOFS_INF_PENDING;
406 spin_unlock(&sbi->fs_lock);
407 status = autofs4_mount_wait(dentry, 0);
408 spin_lock(&sbi->fs_lock);
409 ino->flags &= ~AUTOFS_INF_PENDING;
410 if (status) {
411 spin_unlock(&sbi->fs_lock);
412 return ERR_PTR(status);
413 }
414 }
415 spin_unlock(&sbi->fs_lock);
416 done:
417 /* Mount succeeded, check if we ended up with a new dentry */
418 dentry = autofs4_mountpoint_changed(path);
419 if (!dentry)
420 return ERR_PTR(-ENOENT);
421
422 return NULL;
423 }
424
autofs4_d_manage(struct dentry * dentry,bool rcu_walk)425 static int autofs4_d_manage(struct dentry *dentry, bool rcu_walk)
426 {
427 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
428 struct autofs_info *ino = autofs4_dentry_ino(dentry);
429 int status;
430
431 DPRINTK("dentry=%p %.*s",
432 dentry, dentry->d_name.len, dentry->d_name.name);
433
434 /* The daemon never waits. */
435 if (autofs4_oz_mode(sbi)) {
436 if (!d_mountpoint(dentry))
437 return -EISDIR;
438 return 0;
439 }
440
441 /* Wait for pending expires */
442 if (do_expire_wait(dentry, rcu_walk) == -ECHILD)
443 return -ECHILD;
444
445 /*
446 * This dentry may be under construction so wait on mount
447 * completion.
448 */
449 status = autofs4_mount_wait(dentry, rcu_walk);
450 if (status)
451 return status;
452
453 if (rcu_walk) {
454 /* We don't need fs_lock in rcu_walk mode,
455 * just testing 'AUTOFS_INFO_NO_RCU' is enough.
456 * simple_empty() takes a spinlock, so leave it
457 * to last.
458 * We only return -EISDIR when certain this isn't
459 * a mount-trap.
460 */
461 struct inode *inode;
462 if (ino->flags & AUTOFS_INF_WANT_EXPIRE)
463 return 0;
464 if (d_mountpoint(dentry))
465 return 0;
466 inode = ACCESS_ONCE(dentry->d_inode);
467 if (inode && S_ISLNK(inode->i_mode))
468 return -EISDIR;
469 if (list_empty(&dentry->d_subdirs))
470 return 0;
471 if (!simple_empty(dentry))
472 return -EISDIR;
473 return 0;
474 }
475
476 spin_lock(&sbi->fs_lock);
477 /*
478 * If the dentry has been selected for expire while we slept
479 * on the lock then it might go away. We'll deal with that in
480 * ->d_automount() and wait on a new mount if the expire
481 * succeeds or return here if it doesn't (since there's no
482 * mount to follow with a rootless multi-mount).
483 */
484 if (!(ino->flags & AUTOFS_INF_EXPIRING)) {
485 /*
486 * Any needed mounting has been completed and the path
487 * updated so check if this is a rootless multi-mount so
488 * we can avoid needless calls ->d_automount() and avoid
489 * an incorrect ELOOP error return.
490 */
491 if ((!d_mountpoint(dentry) && !simple_empty(dentry)) ||
492 (dentry->d_inode && S_ISLNK(dentry->d_inode->i_mode)))
493 status = -EISDIR;
494 }
495 spin_unlock(&sbi->fs_lock);
496
497 return status;
498 }
499
500 /* Lookups in the root directory */
autofs4_lookup(struct inode * dir,struct dentry * dentry,unsigned int flags)501 static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
502 {
503 struct autofs_sb_info *sbi;
504 struct autofs_info *ino;
505 struct dentry *active;
506
507 DPRINTK("name = %.*s", dentry->d_name.len, dentry->d_name.name);
508
509 /* File name too long to exist */
510 if (dentry->d_name.len > NAME_MAX)
511 return ERR_PTR(-ENAMETOOLONG);
512
513 sbi = autofs4_sbi(dir->i_sb);
514
515 DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
516 current->pid, task_pgrp_nr(current), sbi->catatonic,
517 autofs4_oz_mode(sbi));
518
519 active = autofs4_lookup_active(dentry);
520 if (active) {
521 return active;
522 } else {
523 /*
524 * A dentry that is not within the root can never trigger a
525 * mount operation, unless the directory already exists, so we
526 * can return fail immediately. The daemon however does need
527 * to create directories within the file system.
528 */
529 if (!autofs4_oz_mode(sbi) && !IS_ROOT(dentry->d_parent))
530 return ERR_PTR(-ENOENT);
531
532 /* Mark entries in the root as mount triggers */
533 if (autofs_type_indirect(sbi->type) && IS_ROOT(dentry->d_parent))
534 __managed_dentry_set_managed(dentry);
535
536 ino = autofs4_new_ino(sbi);
537 if (!ino)
538 return ERR_PTR(-ENOMEM);
539
540 dentry->d_fsdata = ino;
541 ino->dentry = dentry;
542
543 autofs4_add_active(dentry);
544
545 d_instantiate(dentry, NULL);
546 }
547 return NULL;
548 }
549
autofs4_dir_symlink(struct inode * dir,struct dentry * dentry,const char * symname)550 static int autofs4_dir_symlink(struct inode *dir,
551 struct dentry *dentry,
552 const char *symname)
553 {
554 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
555 struct autofs_info *ino = autofs4_dentry_ino(dentry);
556 struct autofs_info *p_ino;
557 struct inode *inode;
558 size_t size = strlen(symname);
559 char *cp;
560
561 DPRINTK("%s <- %.*s", symname,
562 dentry->d_name.len, dentry->d_name.name);
563
564 if (!autofs4_oz_mode(sbi))
565 return -EACCES;
566
567 BUG_ON(!ino);
568
569 autofs4_clean_ino(ino);
570
571 autofs4_del_active(dentry);
572
573 cp = kmalloc(size + 1, GFP_KERNEL);
574 if (!cp)
575 return -ENOMEM;
576
577 strcpy(cp, symname);
578
579 inode = autofs4_get_inode(dir->i_sb, S_IFLNK | 0555);
580 if (!inode) {
581 kfree(cp);
582 if (!dentry->d_fsdata)
583 kfree(ino);
584 return -ENOMEM;
585 }
586 inode->i_private = cp;
587 inode->i_size = size;
588 d_add(dentry, inode);
589
590 dget(dentry);
591 atomic_inc(&ino->count);
592 p_ino = autofs4_dentry_ino(dentry->d_parent);
593 if (p_ino && !IS_ROOT(dentry))
594 atomic_inc(&p_ino->count);
595
596 dir->i_mtime = CURRENT_TIME;
597
598 return 0;
599 }
600
601 /*
602 * NOTE!
603 *
604 * Normal filesystems would do a "d_delete()" to tell the VFS dcache
605 * that the file no longer exists. However, doing that means that the
606 * VFS layer can turn the dentry into a negative dentry. We don't want
607 * this, because the unlink is probably the result of an expire.
608 * We simply d_drop it and add it to a expiring list in the super block,
609 * which allows the dentry lookup to check for an incomplete expire.
610 *
611 * If a process is blocked on the dentry waiting for the expire to finish,
612 * it will invalidate the dentry and try to mount with a new one.
613 *
614 * Also see autofs4_dir_rmdir()..
615 */
autofs4_dir_unlink(struct inode * dir,struct dentry * dentry)616 static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
617 {
618 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
619 struct autofs_info *ino = autofs4_dentry_ino(dentry);
620 struct autofs_info *p_ino;
621
622 /* This allows root to remove symlinks */
623 if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN))
624 return -EPERM;
625
626 if (atomic_dec_and_test(&ino->count)) {
627 p_ino = autofs4_dentry_ino(dentry->d_parent);
628 if (p_ino && !IS_ROOT(dentry))
629 atomic_dec(&p_ino->count);
630 }
631 dput(ino->dentry);
632
633 dentry->d_inode->i_size = 0;
634 clear_nlink(dentry->d_inode);
635
636 dir->i_mtime = CURRENT_TIME;
637
638 spin_lock(&sbi->lookup_lock);
639 __autofs4_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 */
autofs_set_leaf_automount_flags(struct dentry * dentry)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 return;
673 }
674
autofs_clear_leaf_automount_flags(struct dentry * dentry)675 static void autofs_clear_leaf_automount_flags(struct dentry *dentry)
676 {
677 struct list_head *d_child;
678 struct dentry *parent;
679
680 /* flags for dentrys in the root are handled elsewhere */
681 if (IS_ROOT(dentry->d_parent))
682 return;
683
684 managed_dentry_clear_managed(dentry);
685
686 parent = dentry->d_parent;
687 /* only consider parents below dentrys in the root */
688 if (IS_ROOT(parent->d_parent))
689 return;
690 d_child = &dentry->d_child;
691 /* Set parent managed if it's becoming empty */
692 if (d_child->next == &parent->d_subdirs &&
693 d_child->prev == &parent->d_subdirs)
694 managed_dentry_set_managed(parent);
695 return;
696 }
697
autofs4_dir_rmdir(struct inode * dir,struct dentry * dentry)698 static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
699 {
700 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
701 struct autofs_info *ino = autofs4_dentry_ino(dentry);
702 struct autofs_info *p_ino;
703
704 DPRINTK("dentry %p, removing %.*s",
705 dentry, dentry->d_name.len, dentry->d_name.name);
706
707 if (!autofs4_oz_mode(sbi))
708 return -EACCES;
709
710 spin_lock(&sbi->lookup_lock);
711 if (!simple_empty(dentry)) {
712 spin_unlock(&sbi->lookup_lock);
713 return -ENOTEMPTY;
714 }
715 __autofs4_add_expiring(dentry);
716 d_drop(dentry);
717 spin_unlock(&sbi->lookup_lock);
718
719 if (sbi->version < 5)
720 autofs_clear_leaf_automount_flags(dentry);
721
722 if (atomic_dec_and_test(&ino->count)) {
723 p_ino = autofs4_dentry_ino(dentry->d_parent);
724 if (p_ino && dentry->d_parent != dentry)
725 atomic_dec(&p_ino->count);
726 }
727 dput(ino->dentry);
728 dentry->d_inode->i_size = 0;
729 clear_nlink(dentry->d_inode);
730
731 if (dir->i_nlink)
732 drop_nlink(dir);
733
734 return 0;
735 }
736
autofs4_dir_mkdir(struct inode * dir,struct dentry * dentry,umode_t mode)737 static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
738 {
739 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
740 struct autofs_info *ino = autofs4_dentry_ino(dentry);
741 struct autofs_info *p_ino;
742 struct inode *inode;
743
744 if (!autofs4_oz_mode(sbi))
745 return -EACCES;
746
747 DPRINTK("dentry %p, creating %.*s",
748 dentry, dentry->d_name.len, dentry->d_name.name);
749
750 BUG_ON(!ino);
751
752 autofs4_clean_ino(ino);
753
754 autofs4_del_active(dentry);
755
756 inode = autofs4_get_inode(dir->i_sb, S_IFDIR | 0555);
757 if (!inode)
758 return -ENOMEM;
759 d_add(dentry, inode);
760
761 if (sbi->version < 5)
762 autofs_set_leaf_automount_flags(dentry);
763
764 dget(dentry);
765 atomic_inc(&ino->count);
766 p_ino = autofs4_dentry_ino(dentry->d_parent);
767 if (p_ino && !IS_ROOT(dentry))
768 atomic_inc(&p_ino->count);
769 inc_nlink(dir);
770 dir->i_mtime = CURRENT_TIME;
771
772 return 0;
773 }
774
775 /* Get/set timeout ioctl() operation */
776 #ifdef CONFIG_COMPAT
autofs4_compat_get_set_timeout(struct autofs_sb_info * sbi,compat_ulong_t __user * p)777 static inline int autofs4_compat_get_set_timeout(struct autofs_sb_info *sbi,
778 compat_ulong_t __user *p)
779 {
780 int rv;
781 unsigned long ntimeout;
782
783 if ((rv = get_user(ntimeout, p)) ||
784 (rv = put_user(sbi->exp_timeout/HZ, p)))
785 return rv;
786
787 if (ntimeout > UINT_MAX/HZ)
788 sbi->exp_timeout = 0;
789 else
790 sbi->exp_timeout = ntimeout * HZ;
791
792 return 0;
793 }
794 #endif
795
autofs4_get_set_timeout(struct autofs_sb_info * sbi,unsigned long __user * p)796 static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi,
797 unsigned long __user *p)
798 {
799 int rv;
800 unsigned long ntimeout;
801
802 if ((rv = get_user(ntimeout, p)) ||
803 (rv = put_user(sbi->exp_timeout/HZ, p)))
804 return rv;
805
806 if (ntimeout > ULONG_MAX/HZ)
807 sbi->exp_timeout = 0;
808 else
809 sbi->exp_timeout = ntimeout * HZ;
810
811 return 0;
812 }
813
814 /* Return protocol version */
autofs4_get_protover(struct autofs_sb_info * sbi,int __user * p)815 static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int __user *p)
816 {
817 return put_user(sbi->version, p);
818 }
819
820 /* Return protocol sub version */
autofs4_get_protosubver(struct autofs_sb_info * sbi,int __user * p)821 static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p)
822 {
823 return put_user(sbi->sub_version, p);
824 }
825
826 /*
827 * Tells the daemon whether it can umount the autofs mount.
828 */
autofs4_ask_umount(struct vfsmount * mnt,int __user * p)829 static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p)
830 {
831 int status = 0;
832
833 if (may_umount(mnt))
834 status = 1;
835
836 DPRINTK("returning %d", status);
837
838 status = put_user(status, p);
839
840 return status;
841 }
842
843 /* Identify autofs4_dentries - this is so we can tell if there's
844 an extra dentry refcount or not. We only hold a refcount on the
845 dentry if its non-negative (ie, d_inode != NULL)
846 */
is_autofs4_dentry(struct dentry * dentry)847 int is_autofs4_dentry(struct dentry *dentry)
848 {
849 return dentry && dentry->d_inode &&
850 dentry->d_op == &autofs4_dentry_operations &&
851 dentry->d_fsdata != NULL;
852 }
853
854 /*
855 * ioctl()'s on the root directory is the chief method for the daemon to
856 * generate kernel reactions
857 */
autofs4_root_ioctl_unlocked(struct inode * inode,struct file * filp,unsigned int cmd,unsigned long arg)858 static int autofs4_root_ioctl_unlocked(struct inode *inode, struct file *filp,
859 unsigned int cmd, unsigned long arg)
860 {
861 struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb);
862 void __user *p = (void __user *)arg;
863
864 DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u",
865 cmd,arg,sbi,task_pgrp_nr(current));
866
867 if (_IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
868 _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT)
869 return -ENOTTY;
870
871 if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN))
872 return -EPERM;
873
874 switch(cmd) {
875 case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */
876 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0);
877 case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */
878 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
879 case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
880 autofs4_catatonic_mode(sbi);
881 return 0;
882 case AUTOFS_IOC_PROTOVER: /* Get protocol version */
883 return autofs4_get_protover(sbi, p);
884 case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */
885 return autofs4_get_protosubver(sbi, p);
886 case AUTOFS_IOC_SETTIMEOUT:
887 return autofs4_get_set_timeout(sbi, p);
888 #ifdef CONFIG_COMPAT
889 case AUTOFS_IOC_SETTIMEOUT32:
890 return autofs4_compat_get_set_timeout(sbi, p);
891 #endif
892
893 case AUTOFS_IOC_ASKUMOUNT:
894 return autofs4_ask_umount(filp->f_path.mnt, p);
895
896 /* return a single thing to expire */
897 case AUTOFS_IOC_EXPIRE:
898 return autofs4_expire_run(inode->i_sb,filp->f_path.mnt,sbi, p);
899 /* same as above, but can send multiple expires through pipe */
900 case AUTOFS_IOC_EXPIRE_MULTI:
901 return autofs4_expire_multi(inode->i_sb,filp->f_path.mnt,sbi, p);
902
903 default:
904 return -ENOSYS;
905 }
906 }
907
autofs4_root_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)908 static long autofs4_root_ioctl(struct file *filp,
909 unsigned int cmd, unsigned long arg)
910 {
911 struct inode *inode = file_inode(filp);
912 return autofs4_root_ioctl_unlocked(inode, filp, cmd, arg);
913 }
914
915 #ifdef CONFIG_COMPAT
autofs4_root_compat_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)916 static long autofs4_root_compat_ioctl(struct file *filp,
917 unsigned int cmd, unsigned long arg)
918 {
919 struct inode *inode = file_inode(filp);
920 int ret;
921
922 if (cmd == AUTOFS_IOC_READY || cmd == AUTOFS_IOC_FAIL)
923 ret = autofs4_root_ioctl_unlocked(inode, filp, cmd, arg);
924 else
925 ret = autofs4_root_ioctl_unlocked(inode, filp, cmd,
926 (unsigned long)compat_ptr(arg));
927
928 return ret;
929 }
930 #endif
931