Commit | Line | Data |
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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 | ||
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 int autofs4_dcache_readdir(struct file *, void *, filldir_t); | |
33 | ||
34 | 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 | 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 | struct 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 | ||
57 | struct 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 | ||
65 | static 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 */ | |
9cf6f4b3 | 89 | static void autofs4_update_usage(struct vfsmount *mnt, struct dentry *dentry) |
1da177e4 LT |
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) { | |
9cf6f4b3 | 98 | touch_atime(mnt, dentry); |
1da177e4 LT |
99 | ino->last_used = jiffies; |
100 | } | |
101 | } | |
102 | spin_unlock(&dcache_lock); | |
103 | } | |
104 | ||
105 | /* | |
106 | * From 2.4 kernel readdir.c | |
107 | */ | |
108 | static 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 | ||
167 | static 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 | } | |
223 | out: | |
224 | return 0; | |
225 | } | |
226 | ||
227 | static 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 | } | |
252 | out: | |
253 | return 0; | |
254 | } | |
255 | ||
256 | static 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 | } | |
288 | out: | |
289 | return autofs4_dcache_readdir(file, dirent, filldir); | |
290 | } | |
291 | ||
9cf6f4b3 | 292 | static int try_to_fill_dentry(struct vfsmount *mnt, struct dentry *dentry, int flags) |
1da177e4 | 293 | { |
9cf6f4b3 CH |
294 | struct super_block *sb = mnt->mnt_sb; |
295 | struct autofs_sb_info *sbi = autofs4_sbi(sb); | |
1da177e4 LT |
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)) | |
9cf6f4b3 | 370 | autofs4_update_usage(mnt, dentry); |
1da177e4 LT |
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 | */ | |
384 | static 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) | |
9cf6f4b3 | 395 | status = try_to_fill_dentry(nd->mnt, dentry, flags); |
1da177e4 LT |
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) | |
9cf6f4b3 | 412 | status = try_to_fill_dentry(nd->mnt, dentry, flags); |
1da177e4 LT |
413 | return status; |
414 | } | |
415 | spin_unlock(&dcache_lock); | |
416 | ||
417 | /* Update the usage list */ | |
418 | if (!oz_mode) | |
9cf6f4b3 | 419 | autofs4_update_usage(nd->mnt, dentry); |
1da177e4 LT |
420 | |
421 | return 1; | |
422 | } | |
423 | ||
424 | static 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 */ | |
442 | static struct dentry_operations autofs4_root_dentry_operations = { | |
443 | .d_revalidate = autofs4_revalidate, | |
444 | .d_release = autofs4_dentry_release, | |
445 | }; | |
446 | ||
447 | /* For other dentries */ | |
448 | static 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 */ | |
454 | static 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 = ¤t->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 | ||
525 | static 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 | */ | |
586 | static 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 | ||
607 | static 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 | ||
636 | static 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 */ | |
670 | static 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 */ | |
689 | static 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 */ | |
695 | static 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 | */ | |
704 | static 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 | */ | |
721 | static 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 | */ | |
741 | static 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 | */ | |
759 | int 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 | */ | |
771 | static 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 | } |