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ACPI: update intrd DSDT override console messages
[linux-2.6/sactl.git] / fs / autofs4 / root.c
blob2bbcc8151dc343eae48914aa95748fef401238f7
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, task_pgrp_nr(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 don't hash it. We do this
591 * to serialize our inode creation operations (symlink and
592 * mkdir) which prevents deadlock during the callback to
593 * the daemon. Subsequent user space lookups for the same
594 * dentry are placed on the wait queue while the daemon
595 * itself is allowed passage unresticted so the create
596 * operation itself can then hash the dentry. Finally,
597 * we check for the hashed dentry and return the newly
598 * hashed dentry.
599 */
600 dentry->d_op = &autofs4_root_dentry_operations;
601
602 dentry->d_fsdata = NULL;
603 d_instantiate(dentry, NULL);
604 } else {
605 struct autofs_info *ino = autofs4_dentry_ino(unhashed);
606 DPRINTK("rehash %p with %p", dentry, unhashed);
607 /*
608 * If we are racing with expire the request might not
609 * be quite complete but the directory has been removed
610 * so it must have been successful, so just wait for it.
611 * We need to ensure the AUTOFS_INF_EXPIRING flag is clear
612 * before continuing as revalidate may fail when calling
613 * try_to_fill_dentry (returning EAGAIN) if we don't.
614 */
615 while (ino && (ino->flags & AUTOFS_INF_EXPIRING)) {
616 DPRINTK("wait for incomplete expire %p name=%.*s",
617 unhashed, unhashed->d_name.len,
618 unhashed->d_name.name);
619 autofs4_wait(sbi, unhashed, NFY_NONE);
620 DPRINTK("request completed");
621 }
622 dentry = unhashed;
623 }
624
625 if (!oz_mode) {
626 spin_lock(&dentry->d_lock);
627 dentry->d_flags |= DCACHE_AUTOFS_PENDING;
628 spin_unlock(&dentry->d_lock);
629 }
630
631 if (dentry->d_op && dentry->d_op->d_revalidate) {
632 mutex_unlock(&dir->i_mutex);
633 (dentry->d_op->d_revalidate)(dentry, nd);
634 mutex_lock(&dir->i_mutex);
635 }
636
637 /*
638 * If we are still pending, check if we had to handle
639 * a signal. If so we can force a restart..
640 */
641 if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
642 /* See if we were interrupted */
643 if (signal_pending(current)) {
644 sigset_t *sigset = &current->pending.signal;
645 if (sigismember (sigset, SIGKILL) ||
646 sigismember (sigset, SIGQUIT) ||
647 sigismember (sigset, SIGINT)) {
648 if (unhashed)
649 dput(unhashed);
650 return ERR_PTR(-ERESTARTNOINTR);
651 }
652 }
653 spin_lock(&dentry->d_lock);
654 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
655 spin_unlock(&dentry->d_lock);
656 }
657
658 /*
659 * If this dentry is unhashed, then we shouldn't honour this
660 * lookup. Returning ENOENT here doesn't do the right thing
661 * for all system calls, but it should be OK for the operations
662 * we permit from an autofs.
663 */
664 if (!oz_mode && d_unhashed(dentry)) {
665 /*
666 * A user space application can (and has done in the past)
667 * remove and re-create this directory during the callback.
668 * This can leave us with an unhashed dentry, but a
669 * successful mount! So we need to perform another
670 * cached lookup in case the dentry now exists.
671 */
672 struct dentry *parent = dentry->d_parent;
673 struct dentry *new = d_lookup(parent, &dentry->d_name);
674 if (new != NULL)
675 dentry = new;
676 else
677 dentry = ERR_PTR(-ENOENT);
678
679 if (unhashed)
680 dput(unhashed);
681
682 return dentry;
683 }
684
685 if (unhashed)
686 return dentry;
687
688 return NULL;
689 }
690
691 static int autofs4_dir_symlink(struct inode *dir,
692 struct dentry *dentry,
693 const char *symname)
694 {
695 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
696 struct autofs_info *ino = autofs4_dentry_ino(dentry);
697 struct autofs_info *p_ino;
698 struct inode *inode;
699 char *cp;
700
701 DPRINTK("%s <- %.*s", symname,
702 dentry->d_name.len, dentry->d_name.name);
703
704 if (!autofs4_oz_mode(sbi))
705 return -EACCES;
706
707 ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555);
708 if (ino == NULL)
709 return -ENOSPC;
710
711 ino->size = strlen(symname);
712 ino->u.symlink = cp = kmalloc(ino->size + 1, GFP_KERNEL);
713
714 if (cp == NULL) {
715 kfree(ino);
716 return -ENOSPC;
717 }
718
719 strcpy(cp, symname);
720
721 inode = autofs4_get_inode(dir->i_sb, ino);
722 d_add(dentry, inode);
723
724 if (dir == dir->i_sb->s_root->d_inode)
725 dentry->d_op = &autofs4_root_dentry_operations;
726 else
727 dentry->d_op = &autofs4_dentry_operations;
728
729 dentry->d_fsdata = ino;
730 ino->dentry = dget(dentry);
731 atomic_inc(&ino->count);
732 p_ino = autofs4_dentry_ino(dentry->d_parent);
733 if (p_ino && dentry->d_parent != dentry)
734 atomic_inc(&p_ino->count);
735 ino->inode = inode;
736
737 dir->i_mtime = CURRENT_TIME;
738
739 return 0;
740 }
741
742 /*
743 * NOTE!
744 *
745 * Normal filesystems would do a "d_delete()" to tell the VFS dcache
746 * that the file no longer exists. However, doing that means that the
747 * VFS layer can turn the dentry into a negative dentry. We don't want
748 * this, because the unlink is probably the result of an expire.
749 * We simply d_drop it and add it to a rehash candidates list in the
750 * super block, which allows the dentry lookup to reuse it retaining
751 * the flags, such as expire in progress, in case we're racing with expire.
752 *
753 * If a process is blocked on the dentry waiting for the expire to finish,
754 * it will invalidate the dentry and try to mount with a new one.
755 *
756 * Also see autofs4_dir_rmdir()..
757 */
758 static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
759 {
760 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
761 struct autofs_info *ino = autofs4_dentry_ino(dentry);
762 struct autofs_info *p_ino;
763
764 /* This allows root to remove symlinks */
765 if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN))
766 return -EACCES;
767
768 if (atomic_dec_and_test(&ino->count)) {
769 p_ino = autofs4_dentry_ino(dentry->d_parent);
770 if (p_ino && dentry->d_parent != dentry)
771 atomic_dec(&p_ino->count);
772 }
773 dput(ino->dentry);
774
775 dentry->d_inode->i_size = 0;
776 clear_nlink(dentry->d_inode);
777
778 dir->i_mtime = CURRENT_TIME;
779
780 spin_lock(&dcache_lock);
781 spin_lock(&sbi->rehash_lock);
782 list_add(&ino->rehash, &sbi->rehash_list);
783 spin_unlock(&sbi->rehash_lock);
784 spin_lock(&dentry->d_lock);
785 __d_drop(dentry);
786 spin_unlock(&dentry->d_lock);
787 spin_unlock(&dcache_lock);
788
789 return 0;
790 }
791
792 static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
793 {
794 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
795 struct autofs_info *ino = autofs4_dentry_ino(dentry);
796 struct autofs_info *p_ino;
797
798 DPRINTK("dentry %p, removing %.*s",
799 dentry, dentry->d_name.len, dentry->d_name.name);
800
801 if (!autofs4_oz_mode(sbi))
802 return -EACCES;
803
804 spin_lock(&dcache_lock);
805 if (!list_empty(&dentry->d_subdirs)) {
806 spin_unlock(&dcache_lock);
807 return -ENOTEMPTY;
808 }
809 spin_lock(&sbi->rehash_lock);
810 list_add(&ino->rehash, &sbi->rehash_list);
811 spin_unlock(&sbi->rehash_lock);
812 spin_lock(&dentry->d_lock);
813 __d_drop(dentry);
814 spin_unlock(&dentry->d_lock);
815 spin_unlock(&dcache_lock);
816
817 if (atomic_dec_and_test(&ino->count)) {
818 p_ino = autofs4_dentry_ino(dentry->d_parent);
819 if (p_ino && dentry->d_parent != dentry)
820 atomic_dec(&p_ino->count);
821 }
822 dput(ino->dentry);
823 dentry->d_inode->i_size = 0;
824 clear_nlink(dentry->d_inode);
825
826 if (dir->i_nlink)
827 drop_nlink(dir);
828
829 return 0;
830 }
831
832 static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
833 {
834 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
835 struct autofs_info *ino = autofs4_dentry_ino(dentry);
836 struct autofs_info *p_ino;
837 struct inode *inode;
838
839 if (!autofs4_oz_mode(sbi))
840 return -EACCES;
841
842 DPRINTK("dentry %p, creating %.*s",
843 dentry, dentry->d_name.len, dentry->d_name.name);
844
845 ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555);
846 if (ino == NULL)
847 return -ENOSPC;
848
849 inode = autofs4_get_inode(dir->i_sb, ino);
850 d_add(dentry, inode);
851
852 if (dir == dir->i_sb->s_root->d_inode)
853 dentry->d_op = &autofs4_root_dentry_operations;
854 else
855 dentry->d_op = &autofs4_dentry_operations;
856
857 dentry->d_fsdata = ino;
858 ino->dentry = dget(dentry);
859 atomic_inc(&ino->count);
860 p_ino = autofs4_dentry_ino(dentry->d_parent);
861 if (p_ino && dentry->d_parent != dentry)
862 atomic_inc(&p_ino->count);
863 ino->inode = inode;
864 inc_nlink(dir);
865 dir->i_mtime = CURRENT_TIME;
866
867 return 0;
868 }
869
870 /* Get/set timeout ioctl() operation */
871 static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi,
872 unsigned long __user *p)
873 {
874 int rv;
875 unsigned long ntimeout;
876
877 if ((rv = get_user(ntimeout, p)) ||
878 (rv = put_user(sbi->exp_timeout/HZ, p)))
879 return rv;
880
881 if (ntimeout > ULONG_MAX/HZ)
882 sbi->exp_timeout = 0;
883 else
884 sbi->exp_timeout = ntimeout * HZ;
885
886 return 0;
887 }
888
889 /* Return protocol version */
890 static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int __user *p)
891 {
892 return put_user(sbi->version, p);
893 }
894
895 /* Return protocol sub version */
896 static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p)
897 {
898 return put_user(sbi->sub_version, p);
899 }
900
901 /*
902 * Tells the daemon whether we need to reghost or not. Also, clears
903 * the reghost_needed flag.
904 */
905 static inline int autofs4_ask_reghost(struct autofs_sb_info *sbi, int __user *p)
906 {
907 int status;
908
909 DPRINTK("returning %d", sbi->needs_reghost);
910
911 status = put_user(sbi->needs_reghost, p);
912 if (status)
913 return status;
914
915 sbi->needs_reghost = 0;
916 return 0;
917 }
918
919 /*
920 * Enable / Disable reghosting ioctl() operation
921 */
922 static inline int autofs4_toggle_reghost(struct autofs_sb_info *sbi, int __user *p)
923 {
924 int status;
925 int val;
926
927 status = get_user(val, p);
928
929 DPRINTK("reghost = %d", val);
930
931 if (status)
932 return status;
933
934 /* turn on/off reghosting, with the val */
935 sbi->reghost_enabled = val;
936 return 0;
937 }
938
939 /*
940 * Tells the daemon whether it can umount the autofs mount.
941 */
942 static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p)
943 {
944 int status = 0;
945
946 if (may_umount(mnt))
947 status = 1;
948
949 DPRINTK("returning %d", status);
950
951 status = put_user(status, p);
952
953 return status;
954 }
955
956 /* Identify autofs4_dentries - this is so we can tell if there's
957 an extra dentry refcount or not. We only hold a refcount on the
958 dentry if its non-negative (ie, d_inode != NULL)
959 */
960 int is_autofs4_dentry(struct dentry *dentry)
961 {
962 return dentry && dentry->d_inode &&
963 (dentry->d_op == &autofs4_root_dentry_operations ||
964 dentry->d_op == &autofs4_dentry_operations) &&
965 dentry->d_fsdata != NULL;
966 }
967
968 /*
969 * ioctl()'s on the root directory is the chief method for the daemon to
970 * generate kernel reactions
971 */
972 static int autofs4_root_ioctl(struct inode *inode, struct file *filp,
973 unsigned int cmd, unsigned long arg)
974 {
975 struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb);
976 void __user *p = (void __user *)arg;
977
978 DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u",
979 cmd,arg,sbi,task_pgrp_nr(current));
980
981 if (_IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
982 _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT)
983 return -ENOTTY;
984
985 if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN))
986 return -EPERM;
987
988 switch(cmd) {
989 case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */
990 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0);
991 case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */
992 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
993 case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
994 autofs4_catatonic_mode(sbi);
995 return 0;
996 case AUTOFS_IOC_PROTOVER: /* Get protocol version */
997 return autofs4_get_protover(sbi, p);
998 case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */
999 return autofs4_get_protosubver(sbi, p);
1000 case AUTOFS_IOC_SETTIMEOUT:
1001 return autofs4_get_set_timeout(sbi, p);
1002
1003 case AUTOFS_IOC_TOGGLEREGHOST:
1004 return autofs4_toggle_reghost(sbi, p);
1005 case AUTOFS_IOC_ASKREGHOST:
1006 return autofs4_ask_reghost(sbi, p);
1007
1008 case AUTOFS_IOC_ASKUMOUNT:
1009 return autofs4_ask_umount(filp->f_path.mnt, p);
1010
1011 /* return a single thing to expire */
1012 case AUTOFS_IOC_EXPIRE:
1013 return autofs4_expire_run(inode->i_sb,filp->f_path.mnt,sbi, p);
1014 /* same as above, but can send multiple expires through pipe */
1015 case AUTOFS_IOC_EXPIRE_MULTI:
1016 return autofs4_expire_multi(inode->i_sb,filp->f_path.mnt,sbi, p);
1017
1018 default:
1019 return -ENOSYS;
1020 }
1021 }
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