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header cleaning: don't include smp_lock.h when not used
[usb.git] / fs / autofs4 / root.c
blob15170f4e13a763e704af9a6b9871f843a1d65a8a
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/param.h>
19 #include <linux/time.h>
20 #include "autofs_i.h"
21
22 static int autofs4_dir_symlink(struct inode *,struct dentry *,const char *);
23 static int autofs4_dir_unlink(struct inode *,struct dentry *);
24 static int autofs4_dir_rmdir(struct inode *,struct dentry *);
25 static int autofs4_dir_mkdir(struct inode *,struct dentry *,int);
26 static int autofs4_root_ioctl(struct inode *, struct file *,unsigned int,unsigned long);
27 static int autofs4_dir_open(struct inode *inode, struct file *file);
28 static int autofs4_dir_close(struct inode *inode, struct file *file);
29 static int autofs4_dir_readdir(struct file * filp, void * dirent, filldir_t filldir);
30 static int autofs4_root_readdir(struct file * filp, void * dirent, filldir_t filldir);
31 static struct dentry *autofs4_lookup(struct inode *,struct dentry *, struct nameidata *);
32 static void *autofs4_follow_link(struct dentry *, struct nameidata *);
33
34 const struct file_operations autofs4_root_operations = {
35 .open = dcache_dir_open,
36 .release = dcache_dir_close,
37 .read = generic_read_dir,
38 .readdir = autofs4_root_readdir,
39 .ioctl = autofs4_root_ioctl,
40 };
41
42 const struct file_operations autofs4_dir_operations = {
43 .open = autofs4_dir_open,
44 .release = autofs4_dir_close,
45 .read = generic_read_dir,
46 .readdir = autofs4_dir_readdir,
47 };
48
49 const struct inode_operations autofs4_indirect_root_inode_operations = {
50 .lookup = autofs4_lookup,
51 .unlink = autofs4_dir_unlink,
52 .symlink = autofs4_dir_symlink,
53 .mkdir = autofs4_dir_mkdir,
54 .rmdir = autofs4_dir_rmdir,
55 };
56
57 const struct inode_operations autofs4_direct_root_inode_operations = {
58 .lookup = autofs4_lookup,
59 .unlink = autofs4_dir_unlink,
60 .mkdir = autofs4_dir_mkdir,
61 .rmdir = autofs4_dir_rmdir,
62 .follow_link = autofs4_follow_link,
63 };
64
65 const struct inode_operations autofs4_dir_inode_operations = {
66 .lookup = autofs4_lookup,
67 .unlink = autofs4_dir_unlink,
68 .symlink = autofs4_dir_symlink,
69 .mkdir = autofs4_dir_mkdir,
70 .rmdir = autofs4_dir_rmdir,
71 };
72
73 static int autofs4_root_readdir(struct file *file, void *dirent,
74 filldir_t filldir)
75 {
76 struct autofs_sb_info *sbi = autofs4_sbi(file->f_path.dentry->d_sb);
77 int oz_mode = autofs4_oz_mode(sbi);
78
79 DPRINTK("called, filp->f_pos = %lld", file->f_pos);
80
81 /*
82 * Don't set reghost flag if:
83 * 1) f_pos is larger than zero -- we've already been here.
84 * 2) we haven't even enabled reghosting in the 1st place.
85 * 3) this is the daemon doing a readdir
86 */
87 if (oz_mode && file->f_pos == 0 && sbi->reghost_enabled)
88 sbi->needs_reghost = 1;
89
90 DPRINTK("needs_reghost = %d", sbi->needs_reghost);
91
92 return dcache_readdir(file, dirent, filldir);
93 }
94
95 static int autofs4_dir_open(struct inode *inode, struct file *file)
96 {
97 struct dentry *dentry = file->f_path.dentry;
98 struct vfsmount *mnt = file->f_path.mnt;
99 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
100 struct dentry *cursor;
101 int status;
102
103 status = dcache_dir_open(inode, file);
104 if (status)
105 goto out;
106
107 cursor = file->private_data;
108 cursor->d_fsdata = NULL;
109
110 DPRINTK("file=%p dentry=%p %.*s",
111 file, dentry, dentry->d_name.len, dentry->d_name.name);
112
113 if (autofs4_oz_mode(sbi))
114 goto out;
115
116 if (autofs4_ispending(dentry)) {
117 DPRINTK("dentry busy");
118 dcache_dir_close(inode, file);
119 status = -EBUSY;
120 goto out;
121 }
122
123 status = -ENOENT;
124 if (!d_mountpoint(dentry) && dentry->d_op && dentry->d_op->d_revalidate) {
125 struct nameidata nd;
126 int empty, ret;
127
128 /* In case there are stale directory dentrys from a failed mount */
129 spin_lock(&dcache_lock);
130 empty = list_empty(&dentry->d_subdirs);
131 spin_unlock(&dcache_lock);
132
133 if (!empty)
134 d_invalidate(dentry);
135
136 nd.flags = LOOKUP_DIRECTORY;
137 ret = (dentry->d_op->d_revalidate)(dentry, &nd);
138
139 if (ret <= 0) {
140 if (ret < 0)
141 status = ret;
142 dcache_dir_close(inode, file);
143 goto out;
144 }
145 }
146
147 if (d_mountpoint(dentry)) {
148 struct file *fp = NULL;
149 struct vfsmount *fp_mnt = mntget(mnt);
150 struct dentry *fp_dentry = dget(dentry);
151
152 if (!autofs4_follow_mount(&fp_mnt, &fp_dentry)) {
153 dput(fp_dentry);
154 mntput(fp_mnt);
155 dcache_dir_close(inode, file);
156 goto out;
157 }
158
159 fp = dentry_open(fp_dentry, fp_mnt, file->f_flags);
160 status = PTR_ERR(fp);
161 if (IS_ERR(fp)) {
162 dcache_dir_close(inode, file);
163 goto out;
164 }
165 cursor->d_fsdata = fp;
166 }
167 return 0;
168 out:
169 return status;
170 }
171
172 static int autofs4_dir_close(struct inode *inode, struct file *file)
173 {
174 struct dentry *dentry = file->f_path.dentry;
175 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
176 struct dentry *cursor = file->private_data;
177 int status = 0;
178
179 DPRINTK("file=%p dentry=%p %.*s",
180 file, dentry, dentry->d_name.len, dentry->d_name.name);
181
182 if (autofs4_oz_mode(sbi))
183 goto out;
184
185 if (autofs4_ispending(dentry)) {
186 DPRINTK("dentry busy");
187 status = -EBUSY;
188 goto out;
189 }
190
191 if (d_mountpoint(dentry)) {
192 struct file *fp = cursor->d_fsdata;
193 if (!fp) {
194 status = -ENOENT;
195 goto out;
196 }
197 filp_close(fp, current->files);
198 }
199 out:
200 dcache_dir_close(inode, file);
201 return status;
202 }
203
204 static int autofs4_dir_readdir(struct file *file, void *dirent, filldir_t filldir)
205 {
206 struct dentry *dentry = file->f_path.dentry;
207 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
208 struct dentry *cursor = file->private_data;
209 int status;
210
211 DPRINTK("file=%p dentry=%p %.*s",
212 file, dentry, dentry->d_name.len, dentry->d_name.name);
213
214 if (autofs4_oz_mode(sbi))
215 goto out;
216
217 if (autofs4_ispending(dentry)) {
218 DPRINTK("dentry busy");
219 return -EBUSY;
220 }
221
222 if (d_mountpoint(dentry)) {
223 struct file *fp = cursor->d_fsdata;
224
225 if (!fp)
226 return -ENOENT;
227
228 if (!fp->f_op || !fp->f_op->readdir)
229 goto out;
230
231 status = vfs_readdir(fp, filldir, dirent);
232 file->f_pos = fp->f_pos;
233 if (status)
234 autofs4_copy_atime(file, fp);
235 return status;
236 }
237 out:
238 return dcache_readdir(file, dirent, filldir);
239 }
240
241 static int try_to_fill_dentry(struct dentry *dentry, int flags)
242 {
243 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
244 struct autofs_info *ino = autofs4_dentry_ino(dentry);
245 int status = 0;
246
247 /* Block on any pending expiry here; invalidate the dentry
248 when expiration is done to trigger mount request with a new
249 dentry */
250 if (ino && (ino->flags & AUTOFS_INF_EXPIRING)) {
251 DPRINTK("waiting for expire %p name=%.*s",
252 dentry, dentry->d_name.len, dentry->d_name.name);
253
254 status = autofs4_wait(sbi, dentry, NFY_NONE);
255
256 DPRINTK("expire done status=%d", status);
257
258 /*
259 * If the directory still exists the mount request must
260 * continue otherwise it can't be followed at the right
261 * time during the walk.
262 */
263 status = d_invalidate(dentry);
264 if (status != -EBUSY)
265 return -EAGAIN;
266 }
267
268 DPRINTK("dentry=%p %.*s ino=%p",
269 dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_inode);
270
271 /*
272 * Wait for a pending mount, triggering one if there
273 * isn't one already
274 */
275 if (dentry->d_inode == NULL) {
276 DPRINTK("waiting for mount name=%.*s",
277 dentry->d_name.len, dentry->d_name.name);
278
279 status = autofs4_wait(sbi, dentry, NFY_MOUNT);
280
281 DPRINTK("mount done status=%d", status);
282
283 /* Turn this into a real negative dentry? */
284 if (status == -ENOENT) {
285 spin_lock(&dentry->d_lock);
286 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
287 spin_unlock(&dentry->d_lock);
288 return status;
289 } else if (status) {
290 /* Return a negative dentry, but leave it "pending" */
291 return status;
292 }
293 /* Trigger mount for path component or follow link */
294 } else if (flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY) ||
295 current->link_count) {
296 DPRINTK("waiting for mount name=%.*s",
297 dentry->d_name.len, dentry->d_name.name);
298
299 spin_lock(&dentry->d_lock);
300 dentry->d_flags |= DCACHE_AUTOFS_PENDING;
301 spin_unlock(&dentry->d_lock);
302 status = autofs4_wait(sbi, dentry, NFY_MOUNT);
303
304 DPRINTK("mount done status=%d", status);
305
306 if (status) {
307 spin_lock(&dentry->d_lock);
308 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
309 spin_unlock(&dentry->d_lock);
310 return status;
311 }
312 }
313
314 /* Initialize expiry counter after successful mount */
315 if (ino)
316 ino->last_used = jiffies;
317
318 spin_lock(&dentry->d_lock);
319 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
320 spin_unlock(&dentry->d_lock);
321 return status;
322 }
323
324 /* For autofs direct mounts the follow link triggers the mount */
325 static void *autofs4_follow_link(struct dentry *dentry, struct nameidata *nd)
326 {
327 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
328 struct autofs_info *ino = autofs4_dentry_ino(dentry);
329 int oz_mode = autofs4_oz_mode(sbi);
330 unsigned int lookup_type;
331 int status;
332
333 DPRINTK("dentry=%p %.*s oz_mode=%d nd->flags=%d",
334 dentry, dentry->d_name.len, dentry->d_name.name, oz_mode,
335 nd->flags);
336
337 /* If it's our master or we shouldn't trigger a mount we're done */
338 lookup_type = nd->flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY);
339 if (oz_mode || !lookup_type)
340 goto done;
341
342 /* If an expire request is pending wait for it. */
343 if (ino && (ino->flags & AUTOFS_INF_EXPIRING)) {
344 DPRINTK("waiting for active request %p name=%.*s",
345 dentry, dentry->d_name.len, dentry->d_name.name);
346
347 status = autofs4_wait(sbi, dentry, NFY_NONE);
348
349 DPRINTK("request done status=%d", status);
350 }
351
352 /*
353 * If the dentry contains directories then it is an
354 * autofs multi-mount with no root mount offset. So
355 * don't try to mount it again.
356 */
357 spin_lock(&dcache_lock);
358 if (!d_mountpoint(dentry) && __simple_empty(dentry)) {
359 spin_unlock(&dcache_lock);
360
361 status = try_to_fill_dentry(dentry, 0);
362 if (status)
363 goto out_error;
364
365 /*
366 * The mount succeeded but if there is no root mount
367 * it must be an autofs multi-mount with no root offset
368 * so we don't need to follow the mount.
369 */
370 if (d_mountpoint(dentry)) {
371 if (!autofs4_follow_mount(&nd->mnt, &nd->dentry)) {
372 status = -ENOENT;
373 goto out_error;
374 }
375 }
376
377 goto done;
378 }
379 spin_unlock(&dcache_lock);
380
381 done:
382 return NULL;
383
384 out_error:
385 path_release(nd);
386 return ERR_PTR(status);
387 }
388
389 /*
390 * Revalidate is called on every cache lookup. Some of those
391 * cache lookups may actually happen while the dentry is not
392 * yet completely filled in, and revalidate has to delay such
393 * lookups..
394 */
395 static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd)
396 {
397 struct inode *dir = dentry->d_parent->d_inode;
398 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
399 int oz_mode = autofs4_oz_mode(sbi);
400 int flags = nd ? nd->flags : 0;
401 int status = 1;
402
403 /* Pending dentry */
404 if (autofs4_ispending(dentry)) {
405 /* The daemon never causes a mount to trigger */
406 if (oz_mode)
407 return 1;
408
409 /*
410 * A zero status is success otherwise we have a
411 * negative error code.
412 */
413 status = try_to_fill_dentry(dentry, flags);
414 if (status == 0)
415 return 1;
416
417 /*
418 * A status of EAGAIN here means that the dentry has gone
419 * away while waiting for an expire to complete. If we are
420 * racing with expire lookup will wait for it so this must
421 * be a revalidate and we need to send it to lookup.
422 */
423 if (status == -EAGAIN)
424 return 0;
425
426 return status;
427 }
428
429 /* Negative dentry.. invalidate if "old" */
430 if (dentry->d_inode == NULL)
431 return 0;
432
433 /* Check for a non-mountpoint directory with no contents */
434 spin_lock(&dcache_lock);
435 if (S_ISDIR(dentry->d_inode->i_mode) &&
436 !d_mountpoint(dentry) &&
437 __simple_empty(dentry)) {
438 DPRINTK("dentry=%p %.*s, emptydir",
439 dentry, dentry->d_name.len, dentry->d_name.name);
440 spin_unlock(&dcache_lock);
441 /* The daemon never causes a mount to trigger */
442 if (oz_mode)
443 return 1;
444
445 /*
446 * A zero status is success otherwise we have a
447 * negative error code.
448 */
449 status = try_to_fill_dentry(dentry, flags);
450 if (status == 0)
451 return 1;
452
453 return status;
454 }
455 spin_unlock(&dcache_lock);
456
457 return 1;
458 }
459
460 void autofs4_dentry_release(struct dentry *de)
461 {
462 struct autofs_info *inf;
463
464 DPRINTK("releasing %p", de);
465
466 inf = autofs4_dentry_ino(de);
467 de->d_fsdata = NULL;
468
469 if (inf) {
470 struct autofs_sb_info *sbi = autofs4_sbi(de->d_sb);
471
472 if (sbi) {
473 spin_lock(&sbi->rehash_lock);
474 if (!list_empty(&inf->rehash))
475 list_del(&inf->rehash);
476 spin_unlock(&sbi->rehash_lock);
477 }
478
479 inf->dentry = NULL;
480 inf->inode = NULL;
481
482 autofs4_free_ino(inf);
483 }
484 }
485
486 /* For dentries of directories in the root dir */
487 static struct dentry_operations autofs4_root_dentry_operations = {
488 .d_revalidate = autofs4_revalidate,
489 .d_release = autofs4_dentry_release,
490 };
491
492 /* For other dentries */
493 static struct dentry_operations autofs4_dentry_operations = {
494 .d_revalidate = autofs4_revalidate,
495 .d_release = autofs4_dentry_release,
496 };
497
498 static struct dentry *autofs4_lookup_unhashed(struct autofs_sb_info *sbi, struct dentry *parent, struct qstr *name)
499 {
500 unsigned int len = name->len;
501 unsigned int hash = name->hash;
502 const unsigned char *str = name->name;
503 struct list_head *p, *head;
504
505 spin_lock(&dcache_lock);
506 spin_lock(&sbi->rehash_lock);
507 head = &sbi->rehash_list;
508 list_for_each(p, head) {
509 struct autofs_info *ino;
510 struct dentry *dentry;
511 struct qstr *qstr;
512
513 ino = list_entry(p, struct autofs_info, rehash);
514 dentry = ino->dentry;
515
516 spin_lock(&dentry->d_lock);
517
518 /* Bad luck, we've already been dentry_iput */
519 if (!dentry->d_inode)
520 goto next;
521
522 qstr = &dentry->d_name;
523
524 if (dentry->d_name.hash != hash)
525 goto next;
526 if (dentry->d_parent != parent)
527 goto next;
528
529 if (qstr->len != len)
530 goto next;
531 if (memcmp(qstr->name, str, len))
532 goto next;
533
534 if (d_unhashed(dentry)) {
535 struct autofs_info *ino = autofs4_dentry_ino(dentry);
536 struct inode *inode = dentry->d_inode;
537
538 list_del_init(&ino->rehash);
539 dget(dentry);
540 /*
541 * Make the rehashed dentry negative so the VFS
542 * behaves as it should.
543 */
544 if (inode) {
545 dentry->d_inode = NULL;
546 list_del_init(&dentry->d_alias);
547 spin_unlock(&dentry->d_lock);
548 spin_unlock(&sbi->rehash_lock);
549 spin_unlock(&dcache_lock);
550 iput(inode);
551 return dentry;
552 }
553 spin_unlock(&dentry->d_lock);
554 spin_unlock(&sbi->rehash_lock);
555 spin_unlock(&dcache_lock);
556 return dentry;
557 }
558 next:
559 spin_unlock(&dentry->d_lock);
560 }
561 spin_unlock(&sbi->rehash_lock);
562 spin_unlock(&dcache_lock);
563
564 return NULL;
565 }
566
567 /* Lookups in the root directory */
568 static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
569 {
570 struct autofs_sb_info *sbi;
571 struct dentry *unhashed;
572 int oz_mode;
573
574 DPRINTK("name = %.*s",
575 dentry->d_name.len, dentry->d_name.name);
576
577 /* File name too long to exist */
578 if (dentry->d_name.len > NAME_MAX)
579 return ERR_PTR(-ENAMETOOLONG);
580
581 sbi = autofs4_sbi(dir->i_sb);
582 oz_mode = autofs4_oz_mode(sbi);
583
584 DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
585 current->pid, process_group(current), sbi->catatonic, oz_mode);
586
587 unhashed = autofs4_lookup_unhashed(sbi, dentry->d_parent, &dentry->d_name);
588 if (!unhashed) {
589 /*
590 * Mark the dentry incomplete, but add it. This is needed so
591 * that the VFS layer knows about the dentry, and we can count
592 * on catching any lookups through the revalidate.
593 *
594 * Let all the hard work be done by the revalidate function that
595 * needs to be able to do this anyway..
596 *
597 * We need to do this before we release the directory semaphore.
598 */
599 dentry->d_op = &autofs4_root_dentry_operations;
600
601 dentry->d_fsdata = NULL;
602 d_add(dentry, NULL);
603 } else {
604 struct autofs_info *ino = autofs4_dentry_ino(unhashed);
605 DPRINTK("rehash %p with %p", dentry, unhashed);
606 /*
607 * If we are racing with expire the request might not
608 * be quite complete but the directory has been removed
609 * so it must have been successful, so just wait for it.
610 */
611 if (ino && (ino->flags & AUTOFS_INF_EXPIRING)) {
612 DPRINTK("wait for incomplete expire %p name=%.*s",
613 unhashed, unhashed->d_name.len,
614 unhashed->d_name.name);
615 autofs4_wait(sbi, unhashed, NFY_NONE);
616 DPRINTK("request completed");
617 }
618 d_rehash(unhashed);
619 dentry = unhashed;
620 }
621
622 if (!oz_mode) {
623 spin_lock(&dentry->d_lock);
624 dentry->d_flags |= DCACHE_AUTOFS_PENDING;
625 spin_unlock(&dentry->d_lock);
626 }
627
628 if (dentry->d_op && dentry->d_op->d_revalidate) {
629 mutex_unlock(&dir->i_mutex);
630 (dentry->d_op->d_revalidate)(dentry, nd);
631 mutex_lock(&dir->i_mutex);
632 }
633
634 /*
635 * If we are still pending, check if we had to handle
636 * a signal. If so we can force a restart..
637 */
638 if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
639 /* See if we were interrupted */
640 if (signal_pending(current)) {
641 sigset_t *sigset = &current->pending.signal;
642 if (sigismember (sigset, SIGKILL) ||
643 sigismember (sigset, SIGQUIT) ||
644 sigismember (sigset, SIGINT)) {
645 if (unhashed)
646 dput(unhashed);
647 return ERR_PTR(-ERESTARTNOINTR);
648 }
649 }
650 spin_lock(&dentry->d_lock);
651 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
652 spin_unlock(&dentry->d_lock);
653 }
654
655 /*
656 * If this dentry is unhashed, then we shouldn't honour this
657 * lookup. Returning ENOENT here doesn't do the right thing
658 * for all system calls, but it should be OK for the operations
659 * we permit from an autofs.
660 */
661 if (dentry->d_inode && d_unhashed(dentry)) {
662 /*
663 * A user space application can (and has done in the past)
664 * remove and re-create this directory during the callback.
665 * This can leave us with an unhashed dentry, but a
666 * successful mount! So we need to perform another
667 * cached lookup in case the dentry now exists.
668 */
669 struct dentry *parent = dentry->d_parent;
670 struct dentry *new = d_lookup(parent, &dentry->d_name);
671 if (new != NULL)
672 dentry = new;
673 else
674 dentry = ERR_PTR(-ENOENT);
675
676 if (unhashed)
677 dput(unhashed);
678
679 return dentry;
680 }
681
682 if (unhashed)
683 return dentry;
684
685 return NULL;
686 }
687
688 static int autofs4_dir_symlink(struct inode *dir,
689 struct dentry *dentry,
690 const char *symname)
691 {
692 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
693 struct autofs_info *ino = autofs4_dentry_ino(dentry);
694 struct autofs_info *p_ino;
695 struct inode *inode;
696 char *cp;
697
698 DPRINTK("%s <- %.*s", symname,
699 dentry->d_name.len, dentry->d_name.name);
700
701 if (!autofs4_oz_mode(sbi))
702 return -EACCES;
703
704 ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555);
705 if (ino == NULL)
706 return -ENOSPC;
707
708 ino->size = strlen(symname);
709 ino->u.symlink = cp = kmalloc(ino->size + 1, GFP_KERNEL);
710
711 if (cp == NULL) {
712 kfree(ino);
713 return -ENOSPC;
714 }
715
716 strcpy(cp, symname);
717
718 inode = autofs4_get_inode(dir->i_sb, ino);
719 d_instantiate(dentry, inode);
720
721 if (dir == dir->i_sb->s_root->d_inode)
722 dentry->d_op = &autofs4_root_dentry_operations;
723 else
724 dentry->d_op = &autofs4_dentry_operations;
725
726 dentry->d_fsdata = ino;
727 ino->dentry = dget(dentry);
728 atomic_inc(&ino->count);
729 p_ino = autofs4_dentry_ino(dentry->d_parent);
730 if (p_ino && dentry->d_parent != dentry)
731 atomic_inc(&p_ino->count);
732 ino->inode = inode;
733
734 dir->i_mtime = CURRENT_TIME;
735
736 return 0;
737 }
738
739 /*
740 * NOTE!
741 *
742 * Normal filesystems would do a "d_delete()" to tell the VFS dcache
743 * that the file no longer exists. However, doing that means that the
744 * VFS layer can turn the dentry into a negative dentry. We don't want
745 * this, because the unlink is probably the result of an expire.
746 * We simply d_drop it and add it to a rehash candidates list in the
747 * super block, which allows the dentry lookup to reuse it retaining
748 * the flags, such as expire in progress, in case we're racing with expire.
749 *
750 * If a process is blocked on the dentry waiting for the expire to finish,
751 * it will invalidate the dentry and try to mount with a new one.
752 *
753 * Also see autofs4_dir_rmdir()..
754 */
755 static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
756 {
757 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
758 struct autofs_info *ino = autofs4_dentry_ino(dentry);
759 struct autofs_info *p_ino;
760
761 /* This allows root to remove symlinks */
762 if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
763 return -EACCES;
764
765 if (atomic_dec_and_test(&ino->count)) {
766 p_ino = autofs4_dentry_ino(dentry->d_parent);
767 if (p_ino && dentry->d_parent != dentry)
768 atomic_dec(&p_ino->count);
769 }
770 dput(ino->dentry);
771
772 dentry->d_inode->i_size = 0;
773 clear_nlink(dentry->d_inode);
774
775 dir->i_mtime = CURRENT_TIME;
776
777 spin_lock(&dcache_lock);
778 spin_lock(&sbi->rehash_lock);
779 list_add(&ino->rehash, &sbi->rehash_list);
780 spin_unlock(&sbi->rehash_lock);
781 spin_lock(&dentry->d_lock);
782 __d_drop(dentry);
783 spin_unlock(&dentry->d_lock);
784 spin_unlock(&dcache_lock);
785
786 return 0;
787 }
788
789 static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
790 {
791 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
792 struct autofs_info *ino = autofs4_dentry_ino(dentry);
793 struct autofs_info *p_ino;
794
795 DPRINTK("dentry %p, removing %.*s",
796 dentry, dentry->d_name.len, dentry->d_name.name);
797
798 if (!autofs4_oz_mode(sbi))
799 return -EACCES;
800
801 spin_lock(&dcache_lock);
802 if (!list_empty(&dentry->d_subdirs)) {
803 spin_unlock(&dcache_lock);
804 return -ENOTEMPTY;
805 }
806 spin_lock(&sbi->rehash_lock);
807 list_add(&ino->rehash, &sbi->rehash_list);
808 spin_unlock(&sbi->rehash_lock);
809 spin_lock(&dentry->d_lock);
810 __d_drop(dentry);
811 spin_unlock(&dentry->d_lock);
812 spin_unlock(&dcache_lock);
813
814 if (atomic_dec_and_test(&ino->count)) {
815 p_ino = autofs4_dentry_ino(dentry->d_parent);
816 if (p_ino && dentry->d_parent != dentry)
817 atomic_dec(&p_ino->count);
818 }
819 dput(ino->dentry);
820 dentry->d_inode->i_size = 0;
821 clear_nlink(dentry->d_inode);
822
823 if (dir->i_nlink)
824 drop_nlink(dir);
825
826 return 0;
827 }
828
829 static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
830 {
831 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
832 struct autofs_info *ino = autofs4_dentry_ino(dentry);
833 struct autofs_info *p_ino;
834 struct inode *inode;
835
836 if ( !autofs4_oz_mode(sbi) )
837 return -EACCES;
838
839 DPRINTK("dentry %p, creating %.*s",
840 dentry, dentry->d_name.len, dentry->d_name.name);
841
842 ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555);
843 if (ino == NULL)
844 return -ENOSPC;
845
846 inode = autofs4_get_inode(dir->i_sb, ino);
847 d_instantiate(dentry, inode);
848
849 if (dir == dir->i_sb->s_root->d_inode)
850 dentry->d_op = &autofs4_root_dentry_operations;
851 else
852 dentry->d_op = &autofs4_dentry_operations;
853
854 dentry->d_fsdata = ino;
855 ino->dentry = dget(dentry);
856 atomic_inc(&ino->count);
857 p_ino = autofs4_dentry_ino(dentry->d_parent);
858 if (p_ino && dentry->d_parent != dentry)
859 atomic_inc(&p_ino->count);
860 ino->inode = inode;
861 inc_nlink(dir);
862 dir->i_mtime = CURRENT_TIME;
863
864 return 0;
865 }
866
867 /* Get/set timeout ioctl() operation */
868 static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi,
869 unsigned long __user *p)
870 {
871 int rv;
872 unsigned long ntimeout;
873
874 if ( (rv = get_user(ntimeout, p)) ||
875 (rv = put_user(sbi->exp_timeout/HZ, p)) )
876 return rv;
877
878 if ( ntimeout > ULONG_MAX/HZ )
879 sbi->exp_timeout = 0;
880 else
881 sbi->exp_timeout = ntimeout * HZ;
882
883 return 0;
884 }
885
886 /* Return protocol version */
887 static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int __user *p)
888 {
889 return put_user(sbi->version, p);
890 }
891
892 /* Return protocol sub version */
893 static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p)
894 {
895 return put_user(sbi->sub_version, p);
896 }
897
898 /*
899 * Tells the daemon whether we need to reghost or not. Also, clears
900 * the reghost_needed flag.
901 */
902 static inline int autofs4_ask_reghost(struct autofs_sb_info *sbi, int __user *p)
903 {
904 int status;
905
906 DPRINTK("returning %d", sbi->needs_reghost);
907
908 status = put_user(sbi->needs_reghost, p);
909 if ( status )
910 return status;
911
912 sbi->needs_reghost = 0;
913 return 0;
914 }
915
916 /*
917 * Enable / Disable reghosting ioctl() operation
918 */
919 static inline int autofs4_toggle_reghost(struct autofs_sb_info *sbi, int __user *p)
920 {
921 int status;
922 int val;
923
924 status = get_user(val, p);
925
926 DPRINTK("reghost = %d", val);
927
928 if (status)
929 return status;
930
931 /* turn on/off reghosting, with the val */
932 sbi->reghost_enabled = val;
933 return 0;
934 }
935
936 /*
937 * Tells the daemon whether it can umount the autofs mount.
938 */
939 static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p)
940 {
941 int status = 0;
942
943 if (may_umount(mnt))
944 status = 1;
945
946 DPRINTK("returning %d", status);
947
948 status = put_user(status, p);
949
950 return status;
951 }
952
953 /* Identify autofs4_dentries - this is so we can tell if there's
954 an extra dentry refcount or not. We only hold a refcount on the
955 dentry if its non-negative (ie, d_inode != NULL)
956 */
957 int is_autofs4_dentry(struct dentry *dentry)
958 {
959 return dentry && dentry->d_inode &&
960 (dentry->d_op == &autofs4_root_dentry_operations ||
961 dentry->d_op == &autofs4_dentry_operations) &&
962 dentry->d_fsdata != NULL;
963 }
964
965 /*
966 * ioctl()'s on the root directory is the chief method for the daemon to
967 * generate kernel reactions
968 */
969 static int autofs4_root_ioctl(struct inode *inode, struct file *filp,
970 unsigned int cmd, unsigned long arg)
971 {
972 struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb);
973 void __user *p = (void __user *)arg;
974
975 DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u",
976 cmd,arg,sbi,process_group(current));
977
978 if ( _IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
979 _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT )
980 return -ENOTTY;
981
982 if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
983 return -EPERM;
984
985 switch(cmd) {
986 case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */
987 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0);
988 case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */
989 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
990 case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
991 autofs4_catatonic_mode(sbi);
992 return 0;
993 case AUTOFS_IOC_PROTOVER: /* Get protocol version */
994 return autofs4_get_protover(sbi, p);
995 case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */
996 return autofs4_get_protosubver(sbi, p);
997 case AUTOFS_IOC_SETTIMEOUT:
998 return autofs4_get_set_timeout(sbi, p);
999
1000 case AUTOFS_IOC_TOGGLEREGHOST:
1001 return autofs4_toggle_reghost(sbi, p);
1002 case AUTOFS_IOC_ASKREGHOST:
1003 return autofs4_ask_reghost(sbi, p);
1004
1005 case AUTOFS_IOC_ASKUMOUNT:
1006 return autofs4_ask_umount(filp->f_path.mnt, p);
1007
1008 /* return a single thing to expire */
1009 case AUTOFS_IOC_EXPIRE:
1010 return autofs4_expire_run(inode->i_sb,filp->f_path.mnt,sbi, p);
1011 /* same as above, but can send multiple expires through pipe */
1012 case AUTOFS_IOC_EXPIRE_MULTI:
1013 return autofs4_expire_multi(inode->i_sb,filp->f_path.mnt,sbi, p);
1014
1015 default:
1016 return -ENOSYS;
1017 }
1018 }
USB Experimental Work