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[mirror_ubuntu-zesty-kernel.git] / fs / autofs4 / root.c
CommitLineData
1da177e4
LT		 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 2001-2003 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/errno.h>
16#include <linux/stat.h>
17#include <linux/param.h>
18#include <linux/time.h>
19#include <linux/smp_lock.h>
20#include "autofs_i.h"
21
22static int autofs4_dir_symlink(struct inode *,struct dentry *,const char *);
23static int autofs4_dir_unlink(struct inode *,struct dentry *);
24static int autofs4_dir_rmdir(struct inode *,struct dentry *);
25static int autofs4_dir_mkdir(struct inode *,struct dentry *,int);
26static int autofs4_root_ioctl(struct inode *, struct file *,unsigned int,unsigned long);
27static int autofs4_dir_open(struct inode *inode, struct file *file);
28static int autofs4_dir_close(struct inode *inode, struct file *file);
29static int autofs4_dir_readdir(struct file * filp, void * dirent, filldir_t filldir);
30static int autofs4_root_readdir(struct file * filp, void * dirent, filldir_t filldir);
31static struct dentry *autofs4_lookup(struct inode *,struct dentry *, struct nameidata *);
32static int autofs4_dcache_readdir(struct file *, void *, filldir_t);
33
34struct 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
42struct 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
49struct inode_operations autofs4_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
57struct inode_operations autofs4_dir_inode_operations = {
58 .lookup = autofs4_lookup,
59 .unlink = autofs4_dir_unlink,
60 .symlink = autofs4_dir_symlink,
61 .mkdir = autofs4_dir_mkdir,
62 .rmdir = autofs4_dir_rmdir,
63};
64
65static int autofs4_root_readdir(struct file *file, void *dirent,
66 filldir_t filldir)
67{
68 struct autofs_sb_info *sbi = autofs4_sbi(file->f_dentry->d_sb);
69 int oz_mode = autofs4_oz_mode(sbi);
70
71 DPRINTK("called, filp->f_pos = %lld", file->f_pos);
72
73 /*
74 * Don't set reghost flag if:
75 * 1) f_pos is larger than zero -- we've already been here.
76 * 2) we haven't even enabled reghosting in the 1st place.
77 * 3) this is the daemon doing a readdir
78 */
79 if (oz_mode && file->f_pos == 0 && sbi->reghost_enabled)
80 sbi->needs_reghost = 1;
81
82 DPRINTK("needs_reghost = %d", sbi->needs_reghost);
83
84 return autofs4_dcache_readdir(file, dirent, filldir);
85}
86
87/* Update usage from here to top of tree, so that scan of
88 top-level directories will give a useful result */
89static void autofs4_update_usage(struct dentry *dentry)
90{
91 struct dentry *top = dentry->d_sb->s_root;
92
93 spin_lock(&dcache_lock);
94 for(; dentry != top; dentry = dentry->d_parent) {
95 struct autofs_info *ino = autofs4_dentry_ino(dentry);
96
97 if (ino) {
98 update_atime(dentry->d_inode);
99 ino->last_used = jiffies;
100 }
101 }
102 spin_unlock(&dcache_lock);
103}
104
105/*
106 * From 2.4 kernel readdir.c
107 */
108static int autofs4_dcache_readdir(struct file * filp, void * dirent, filldir_t filldir)
109{
110 int i;
111 struct dentry *dentry = filp->f_dentry;
112
113 i = filp->f_pos;
114 switch (i) {
115 case 0:
116 if (filldir(dirent, ".", 1, i, dentry->d_inode->i_ino, DT_DIR) < 0)
117 break;
118 i++;
119 filp->f_pos++;
120 /* fallthrough */
121 case 1:
122 if (filldir(dirent, "..", 2, i, dentry->d_parent->d_inode->i_ino, DT_DIR) < 0)
123 break;
124 i++;
125 filp->f_pos++;
126 /* fallthrough */
127 default: {
128 struct list_head *list;
129 int j = i-2;
130
131 spin_lock(&dcache_lock);
132 list = dentry->d_subdirs.next;
133
134 for (;;) {
135 if (list == &dentry->d_subdirs) {
136 spin_unlock(&dcache_lock);
137 return 0;
138 }
139 if (!j)
140 break;
141 j--;
142 list = list->next;
143 }
144
145 while(1) {
5160ee6f
ED		 146 struct dentry *de = list_entry(list,
147 struct dentry, d_u.d_child);
1da177e4
LT		 148
149 if (!d_unhashed(de) && de->d_inode) {
150 spin_unlock(&dcache_lock);
151 if (filldir(dirent, de->d_name.name, de->d_name.len, filp->f_pos, de->d_inode->i_ino, DT_UNKNOWN) < 0)
152 break;
153 spin_lock(&dcache_lock);
154 }
155 filp->f_pos++;
156 list = list->next;
157 if (list != &dentry->d_subdirs)
158 continue;
159 spin_unlock(&dcache_lock);
160 break;
161 }
162 }
163 }
164 return 0;
165}
166
167static int autofs4_dir_open(struct inode *inode, struct file *file)
168{
169 struct dentry *dentry = file->f_dentry;
170 struct vfsmount *mnt = file->f_vfsmnt;
171 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
172 int status;
173
174 DPRINTK("file=%p dentry=%p %.*s",
175 file, dentry, dentry->d_name.len, dentry->d_name.name);
176
177 if (autofs4_oz_mode(sbi))
178 goto out;
179
180 if (autofs4_ispending(dentry)) {
181 DPRINTK("dentry busy");
182 return -EBUSY;
183 }
184
185 if (!d_mountpoint(dentry) && dentry->d_op && dentry->d_op->d_revalidate) {
186 struct nameidata nd;
187 int empty;
188
189 /* In case there are stale directory dentrys from a failed mount */
190 spin_lock(&dcache_lock);
191 empty = list_empty(&dentry->d_subdirs);
192 spin_unlock(&dcache_lock);
193
194 if (!empty)
195 d_invalidate(dentry);
196
197 nd.flags = LOOKUP_DIRECTORY;
198 status = (dentry->d_op->d_revalidate)(dentry, &nd);
199
200 if (!status)
201 return -ENOENT;
202 }
203
204 if (d_mountpoint(dentry)) {
205 struct file *fp = NULL;
206 struct vfsmount *fp_mnt = mntget(mnt);
207 struct dentry *fp_dentry = dget(dentry);
208
9b1e3afd
IK		 209 if (!autofs4_follow_mount(&fp_mnt, &fp_dentry)) {
210 dput(fp_dentry);
211 mntput(fp_mnt);
212 return -ENOENT;
213 }
1da177e4
LT		 214
215 fp = dentry_open(fp_dentry, fp_mnt, file->f_flags);
216 status = PTR_ERR(fp);
217 if (IS_ERR(fp)) {
218 file->private_data = NULL;
219 return status;
220 }
221 file->private_data = fp;
222 }
223out:
224 return 0;
225}
226
227static int autofs4_dir_close(struct inode *inode, struct file *file)
228{
229 struct dentry *dentry = file->f_dentry;
230 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
231
232 DPRINTK("file=%p dentry=%p %.*s",
233 file, dentry, dentry->d_name.len, dentry->d_name.name);
234
235 if (autofs4_oz_mode(sbi))
236 goto out;
237
238 if (autofs4_ispending(dentry)) {
239 DPRINTK("dentry busy");
240 return -EBUSY;
241 }
242
243 if (d_mountpoint(dentry)) {
244 struct file *fp = file->private_data;
245
246 if (!fp)
247 return -ENOENT;
248
249 filp_close(fp, current->files);
250 file->private_data = NULL;
251 }
252out:
253 return 0;
254}
255
256static int autofs4_dir_readdir(struct file *file, void *dirent, filldir_t filldir)
257{
258 struct dentry *dentry = file->f_dentry;
259 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
260 int status;
261
262 DPRINTK("file=%p dentry=%p %.*s",
263 file, dentry, dentry->d_name.len, dentry->d_name.name);
264
265 if (autofs4_oz_mode(sbi))
266 goto out;
267
268 if (autofs4_ispending(dentry)) {
269 DPRINTK("dentry busy");
270 return -EBUSY;
271 }
272
273 if (d_mountpoint(dentry)) {
274 struct file *fp = file->private_data;
275
276 if (!fp)
277 return -ENOENT;
278
279 if (!fp->f_op || !fp->f_op->readdir)
280 goto out;
281
282 status = vfs_readdir(fp, filldir, dirent);
283 file->f_pos = fp->f_pos;
284 if (status)
285 autofs4_copy_atime(file, fp);
286 return status;
287 }
288out:
289 return autofs4_dcache_readdir(file, dirent, filldir);
290}
291
292static int try_to_fill_dentry(struct dentry *dentry,
293 struct super_block *sb,
294 struct autofs_sb_info *sbi, int flags)
295{
296 struct autofs_info *de_info = autofs4_dentry_ino(dentry);
297 int status = 0;
298
299 /* Block on any pending expiry here; invalidate the dentry
300 when expiration is done to trigger mount request with a new
301 dentry */
302 if (de_info && (de_info->flags & AUTOFS_INF_EXPIRING)) {
303 DPRINTK("waiting for expire %p name=%.*s",
304 dentry, dentry->d_name.len, dentry->d_name.name);
305
306 status = autofs4_wait(sbi, dentry, NFY_NONE);
307
308 DPRINTK("expire done status=%d", status);
309
1684b2bb
IK		 310 /*
311 * If the directory still exists the mount request must
312 * continue otherwise it can't be followed at the right
313 * time during the walk.
314 */
315 status = d_invalidate(dentry);
316 if (status != -EBUSY)
317 return 0;
1da177e4
LT		 318 }
319
320 DPRINTK("dentry=%p %.*s ino=%p",
321 dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_inode);
322
323 /* Wait for a pending mount, triggering one if there isn't one already */
324 if (dentry->d_inode == NULL) {
325 DPRINTK("waiting for mount name=%.*s",
326 dentry->d_name.len, dentry->d_name.name);
327
328 status = autofs4_wait(sbi, dentry, NFY_MOUNT);
329
330 DPRINTK("mount done status=%d", status);
331
332 if (status && dentry->d_inode)
333 return 0; /* Try to get the kernel to invalidate this dentry */
334
335 /* Turn this into a real negative dentry? */
336 if (status == -ENOENT) {
337 dentry->d_time = jiffies + AUTOFS_NEGATIVE_TIMEOUT;
338 spin_lock(&dentry->d_lock);
339 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
340 spin_unlock(&dentry->d_lock);
341 return 1;
342 } else if (status) {
343 /* Return a negative dentry, but leave it "pending" */
344 return 1;
345 }
346 /* Trigger mount for path component or follow link */
347 } else if (flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY) ||
348 current->link_count) {
349 DPRINTK("waiting for mount name=%.*s",
350 dentry->d_name.len, dentry->d_name.name);
351
352 spin_lock(&dentry->d_lock);
353 dentry->d_flags |= DCACHE_AUTOFS_PENDING;
354 spin_unlock(&dentry->d_lock);
355 status = autofs4_wait(sbi, dentry, NFY_MOUNT);
356
357 DPRINTK("mount done status=%d", status);
358
359 if (status) {
360 spin_lock(&dentry->d_lock);
361 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
362 spin_unlock(&dentry->d_lock);
363 return 0;
364 }
365 }
366
367 /* We don't update the usages for the autofs daemon itself, this
368 is necessary for recursive autofs mounts */
369 if (!autofs4_oz_mode(sbi))
370 autofs4_update_usage(dentry);
371
372 spin_lock(&dentry->d_lock);
373 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
374 spin_unlock(&dentry->d_lock);
375 return 1;
376}
377
378/*
379 * Revalidate is called on every cache lookup. Some of those
380 * cache lookups may actually happen while the dentry is not
381 * yet completely filled in, and revalidate has to delay such
382 * lookups..
383 */
384static int autofs4_revalidate(struct dentry * dentry, struct nameidata *nd)
385{
386 struct inode * dir = dentry->d_parent->d_inode;
387 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
388 int oz_mode = autofs4_oz_mode(sbi);
389 int flags = nd ? nd->flags : 0;
390 int status = 1;
391
392 /* Pending dentry */
393 if (autofs4_ispending(dentry)) {
394 if (!oz_mode)
395 status = try_to_fill_dentry(dentry, dir->i_sb, sbi, flags);
396 return status;
397 }
398
399 /* Negative dentry.. invalidate if "old" */
400 if (dentry->d_inode == NULL)
401 return (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT);
402
403 /* Check for a non-mountpoint directory with no contents */
404 spin_lock(&dcache_lock);
405 if (S_ISDIR(dentry->d_inode->i_mode) &&
406 !d_mountpoint(dentry) &&
407 list_empty(&dentry->d_subdirs)) {
408 DPRINTK("dentry=%p %.*s, emptydir",
409 dentry, dentry->d_name.len, dentry->d_name.name);
410 spin_unlock(&dcache_lock);
411 if (!oz_mode)
412 status = try_to_fill_dentry(dentry, dir->i_sb, sbi, flags);
413 return status;
414 }
415 spin_unlock(&dcache_lock);
416
417 /* Update the usage list */
418 if (!oz_mode)
419 autofs4_update_usage(dentry);
420
421 return 1;
422}
423
424static void autofs4_dentry_release(struct dentry *de)
425{
426 struct autofs_info *inf;
427
428 DPRINTK("releasing %p", de);
429
430 inf = autofs4_dentry_ino(de);
431 de->d_fsdata = NULL;
432
433 if (inf) {
434 inf->dentry = NULL;
435 inf->inode = NULL;
436
437 autofs4_free_ino(inf);
438 }
439}
440
441/* For dentries of directories in the root dir */
442static struct dentry_operations autofs4_root_dentry_operations = {
443 .d_revalidate = autofs4_revalidate,
444 .d_release = autofs4_dentry_release,
445};
446
447/* For other dentries */
448static struct dentry_operations autofs4_dentry_operations = {
449 .d_revalidate = autofs4_revalidate,
450 .d_release = autofs4_dentry_release,
451};
452
453/* Lookups in the root directory */
454static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
455{
456 struct autofs_sb_info *sbi;
457 int oz_mode;
458
459 DPRINTK("name = %.*s",
460 dentry->d_name.len, dentry->d_name.name);
461
462 if (dentry->d_name.len > NAME_MAX)
463 return ERR_PTR(-ENAMETOOLONG);/* File name too long to exist */
464
465 sbi = autofs4_sbi(dir->i_sb);
466
467 oz_mode = autofs4_oz_mode(sbi);
468 DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
469 current->pid, process_group(current), sbi->catatonic, oz_mode);
470
471 /*
472 * Mark the dentry incomplete, but add it. This is needed so
473 * that the VFS layer knows about the dentry, and we can count
474 * on catching any lookups through the revalidate.
475 *
476 * Let all the hard work be done by the revalidate function that
477 * needs to be able to do this anyway..
478 *
479 * We need to do this before we release the directory semaphore.
480 */
481 dentry->d_op = &autofs4_root_dentry_operations;
482
483 if (!oz_mode) {
484 spin_lock(&dentry->d_lock);
485 dentry->d_flags |= DCACHE_AUTOFS_PENDING;
486 spin_unlock(&dentry->d_lock);
487 }
488 dentry->d_fsdata = NULL;
489 d_add(dentry, NULL);
490
491 if (dentry->d_op && dentry->d_op->d_revalidate) {
1b1dcc1b 492 mutex_unlock(&dir->i_mutex);
1da177e4 493 (dentry->d_op->d_revalidate)(dentry, nd);
1b1dcc1b 494 mutex_lock(&dir->i_mutex);
1da177e4
LT		 495 }
496
497 /*
498 * If we are still pending, check if we had to handle
499 * a signal. If so we can force a restart..
500 */
501 if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
502 /* See if we were interrupted */
503 if (signal_pending(current)) {
504 sigset_t *sigset = &current->pending.signal;
505 if (sigismember (sigset, SIGKILL) ||
506 sigismember (sigset, SIGQUIT) ||
507 sigismember (sigset, SIGINT)) {
508 return ERR_PTR(-ERESTARTNOINTR);
509 }
510 }
511 }
512
513 /*
514 * If this dentry is unhashed, then we shouldn't honour this
515 * lookup even if the dentry is positive. Returning ENOENT here
516 * doesn't do the right thing for all system calls, but it should
517 * be OK for the operations we permit from an autofs.
518 */
519 if ( dentry->d_inode && d_unhashed(dentry) )
520 return ERR_PTR(-ENOENT);
521
522 return NULL;
523}
524
525static int autofs4_dir_symlink(struct inode *dir,
526 struct dentry *dentry,
527 const char *symname)
528{
529 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
530 struct autofs_info *ino = autofs4_dentry_ino(dentry);
531 struct inode *inode;
532 char *cp;
533
534 DPRINTK("%s <- %.*s", symname,
535 dentry->d_name.len, dentry->d_name.name);
536
537 if (!autofs4_oz_mode(sbi))
538 return -EACCES;
539
540 ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555);
541 if (ino == NULL)
542 return -ENOSPC;
543
544 ino->size = strlen(symname);
545 ino->u.symlink = cp = kmalloc(ino->size + 1, GFP_KERNEL);
546
547 if (cp == NULL) {
548 kfree(ino);
549 return -ENOSPC;
550 }
551
552 strcpy(cp, symname);
553
554 inode = autofs4_get_inode(dir->i_sb, ino);
555 d_instantiate(dentry, inode);
556
557 if (dir == dir->i_sb->s_root->d_inode)
558 dentry->d_op = &autofs4_root_dentry_operations;
559 else
560 dentry->d_op = &autofs4_dentry_operations;
561
562 dentry->d_fsdata = ino;
563 ino->dentry = dget(dentry);
564 ino->inode = inode;
565
566 dir->i_mtime = CURRENT_TIME;
567
568 return 0;
569}
570
571/*
572 * NOTE!
573 *
574 * Normal filesystems would do a "d_delete()" to tell the VFS dcache
575 * that the file no longer exists. However, doing that means that the
576 * VFS layer can turn the dentry into a negative dentry. We don't want
577 * this, because since the unlink is probably the result of an expire.
578 * We simply d_drop it, which allows the dentry lookup to remount it
579 * if necessary.
580 *
581 * If a process is blocked on the dentry waiting for the expire to finish,
582 * it will invalidate the dentry and try to mount with a new one.
583 *
584 * Also see autofs4_dir_rmdir()..
585 */
586static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
587{
588 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
589 struct autofs_info *ino = autofs4_dentry_ino(dentry);
590
591 /* This allows root to remove symlinks */
592 if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
593 return -EACCES;
594
595 dput(ino->dentry);
596
597 dentry->d_inode->i_size = 0;
598 dentry->d_inode->i_nlink = 0;
599
600 dir->i_mtime = CURRENT_TIME;
601
602 d_drop(dentry);
603
604 return 0;
605}
606
607static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
608{
609 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
610 struct autofs_info *ino = autofs4_dentry_ino(dentry);
611
612 if (!autofs4_oz_mode(sbi))
613 return -EACCES;
614
615 spin_lock(&dcache_lock);
616 if (!list_empty(&dentry->d_subdirs)) {
617 spin_unlock(&dcache_lock);
618 return -ENOTEMPTY;
619 }
620 spin_lock(&dentry->d_lock);
621 __d_drop(dentry);
622 spin_unlock(&dentry->d_lock);
623 spin_unlock(&dcache_lock);
624
625 dput(ino->dentry);
626
627 dentry->d_inode->i_size = 0;
628 dentry->d_inode->i_nlink = 0;
629
630 if (dir->i_nlink)
631 dir->i_nlink--;
632
633 return 0;
634}
635
636static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
637{
638 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
639 struct autofs_info *ino = autofs4_dentry_ino(dentry);
640 struct inode *inode;
641
642 if ( !autofs4_oz_mode(sbi) )
643 return -EACCES;
644
645 DPRINTK("dentry %p, creating %.*s",
646 dentry, dentry->d_name.len, dentry->d_name.name);
647
648 ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555);
649 if (ino == NULL)
650 return -ENOSPC;
651
652 inode = autofs4_get_inode(dir->i_sb, ino);
653 d_instantiate(dentry, inode);
654
655 if (dir == dir->i_sb->s_root->d_inode)
656 dentry->d_op = &autofs4_root_dentry_operations;
657 else
658 dentry->d_op = &autofs4_dentry_operations;
659
660 dentry->d_fsdata = ino;
661 ino->dentry = dget(dentry);
662 ino->inode = inode;
663 dir->i_nlink++;
664 dir->i_mtime = CURRENT_TIME;
665
666 return 0;
667}
668
669/* Get/set timeout ioctl() operation */
670static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi,
671 unsigned long __user *p)
672{
673 int rv;
674 unsigned long ntimeout;
675
676 if ( (rv = get_user(ntimeout, p)) ||
677 (rv = put_user(sbi->exp_timeout/HZ, p)) )
678 return rv;
679
680 if ( ntimeout > ULONG_MAX/HZ )
681 sbi->exp_timeout = 0;
682 else
683 sbi->exp_timeout = ntimeout * HZ;
684
685 return 0;
686}
687
688/* Return protocol version */
689static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int __user *p)
690{
691 return put_user(sbi->version, p);
692}
693
694/* Return protocol sub version */
695static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p)
696{
697 return put_user(sbi->sub_version, p);
698}
699
700/*
701 * Tells the daemon whether we need to reghost or not. Also, clears
702 * the reghost_needed flag.
703 */
704static inline int autofs4_ask_reghost(struct autofs_sb_info *sbi, int __user *p)
705{
706 int status;
707
708 DPRINTK("returning %d", sbi->needs_reghost);
709
710 status = put_user(sbi->needs_reghost, p);
711 if ( status )
712 return status;
713
714 sbi->needs_reghost = 0;
715 return 0;
716}
717
718/*
719 * Enable / Disable reghosting ioctl() operation
720 */
721static inline int autofs4_toggle_reghost(struct autofs_sb_info *sbi, int __user *p)
722{
723 int status;
724 int val;
725
726 status = get_user(val, p);
727
728 DPRINTK("reghost = %d", val);
729
730 if (status)
731 return status;
732
733 /* turn on/off reghosting, with the val */
734 sbi->reghost_enabled = val;
735 return 0;
736}
737
738/*
739* Tells the daemon whether it can umount the autofs mount.
740*/
741static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p)
742{
743 int status = 0;
744
745 if (may_umount(mnt) == 0)
746 status = 1;
747
748 DPRINTK("returning %d", status);
749
750 status = put_user(status, p);
751
752 return status;
753}
754
755/* Identify autofs4_dentries - this is so we can tell if there's
756 an extra dentry refcount or not. We only hold a refcount on the
757 dentry if its non-negative (ie, d_inode != NULL)
758*/
759int is_autofs4_dentry(struct dentry *dentry)
760{
761 return dentry && dentry->d_inode &&
762 (dentry->d_op == &autofs4_root_dentry_operations ||
763 dentry->d_op == &autofs4_dentry_operations) &&
764 dentry->d_fsdata != NULL;
765}
766
767/*
768 * ioctl()'s on the root directory is the chief method for the daemon to
769 * generate kernel reactions
770 */
771static int autofs4_root_ioctl(struct inode *inode, struct file *filp,
772 unsigned int cmd, unsigned long arg)
773{
774 struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb);
775 void __user *p = (void __user *)arg;
776
777 DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u",
778 cmd,arg,sbi,process_group(current));
779
780 if ( _IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
781 _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT )
782 return -ENOTTY;
783
784 if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
785 return -EPERM;
786
787 switch(cmd) {
788 case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */
789 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0);
790 case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */
791 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
792 case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
793 autofs4_catatonic_mode(sbi);
794 return 0;
795 case AUTOFS_IOC_PROTOVER: /* Get protocol version */
796 return autofs4_get_protover(sbi, p);
797 case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */
798 return autofs4_get_protosubver(sbi, p);
799 case AUTOFS_IOC_SETTIMEOUT:
800 return autofs4_get_set_timeout(sbi, p);
801
802 case AUTOFS_IOC_TOGGLEREGHOST:
803 return autofs4_toggle_reghost(sbi, p);
804 case AUTOFS_IOC_ASKREGHOST:
805 return autofs4_ask_reghost(sbi, p);
806
807 case AUTOFS_IOC_ASKUMOUNT:
808 return autofs4_ask_umount(filp->f_vfsmnt, p);
809
810 /* return a single thing to expire */
811 case AUTOFS_IOC_EXPIRE:
812 return autofs4_expire_run(inode->i_sb,filp->f_vfsmnt,sbi, p);
813 /* same as above, but can send multiple expires through pipe */
814 case AUTOFS_IOC_EXPIRE_MULTI:
815 return autofs4_expire_multi(inode->i_sb,filp->f_vfsmnt,sbi, p);
816
817 default:
818 return -ENOSYS;
819 }
820}
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