Commit | Line | Data |
---|---|---|
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> | |
34ca959c | 7 | * Copyright 2001-2006 Ian Kent <raven@themaw.net> |
1da177e4 LT |
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 | ||
16f7e0fe | 15 | #include <linux/capability.h> |
1da177e4 LT |
16 | #include <linux/errno.h> |
17 | #include <linux/stat.h> | |
5a0e3ad6 | 18 | #include <linux/slab.h> |
1da177e4 LT |
19 | #include <linux/param.h> |
20 | #include <linux/time.h> | |
c9243f5b | 21 | #include <linux/compat.h> |
00e300e1 | 22 | #include <linux/mutex.h> |
c9243f5b | 23 | |
1da177e4 LT |
24 | #include "autofs_i.h" |
25 | ||
b5c84bf6 NP |
26 | DEFINE_SPINLOCK(autofs4_lock); |
27 | ||
1da177e4 LT |
28 | static int autofs4_dir_symlink(struct inode *,struct dentry *,const char *); |
29 | static int autofs4_dir_unlink(struct inode *,struct dentry *); | |
30 | static int autofs4_dir_rmdir(struct inode *,struct dentry *); | |
31 | static int autofs4_dir_mkdir(struct inode *,struct dentry *,int); | |
3663df70 | 32 | static long autofs4_root_ioctl(struct file *,unsigned int,unsigned long); |
5a44a73b | 33 | #ifdef CONFIG_COMPAT |
c9243f5b | 34 | static long autofs4_root_compat_ioctl(struct file *,unsigned int,unsigned long); |
5a44a73b | 35 | #endif |
1da177e4 | 36 | static int autofs4_dir_open(struct inode *inode, struct file *file); |
1da177e4 | 37 | static struct dentry *autofs4_lookup(struct inode *,struct dentry *, struct nameidata *); |
71e469db | 38 | static struct vfsmount *autofs4_d_automount(struct path *); |
ab90911f | 39 | static int autofs4_d_manage(struct dentry *, bool, bool); |
1da177e4 | 40 | |
4b6f5d20 | 41 | const struct file_operations autofs4_root_operations = { |
1da177e4 LT |
42 | .open = dcache_dir_open, |
43 | .release = dcache_dir_close, | |
44 | .read = generic_read_dir, | |
aa55ddf3 | 45 | .readdir = dcache_readdir, |
59af1584 | 46 | .llseek = dcache_dir_lseek, |
3663df70 | 47 | .unlocked_ioctl = autofs4_root_ioctl, |
c9243f5b AB |
48 | #ifdef CONFIG_COMPAT |
49 | .compat_ioctl = autofs4_root_compat_ioctl, | |
50 | #endif | |
1da177e4 LT |
51 | }; |
52 | ||
4b6f5d20 | 53 | const struct file_operations autofs4_dir_operations = { |
1da177e4 | 54 | .open = autofs4_dir_open, |
ff9cd499 | 55 | .release = dcache_dir_close, |
1da177e4 | 56 | .read = generic_read_dir, |
ff9cd499 | 57 | .readdir = dcache_readdir, |
59af1584 | 58 | .llseek = dcache_dir_lseek, |
1da177e4 LT |
59 | }; |
60 | ||
754661f1 | 61 | const struct inode_operations autofs4_dir_inode_operations = { |
1da177e4 LT |
62 | .lookup = autofs4_lookup, |
63 | .unlink = autofs4_dir_unlink, | |
64 | .symlink = autofs4_dir_symlink, | |
65 | .mkdir = autofs4_dir_mkdir, | |
66 | .rmdir = autofs4_dir_rmdir, | |
67 | }; | |
68 | ||
71e469db | 69 | const struct dentry_operations autofs4_dentry_operations = { |
71e469db IK |
70 | .d_automount = autofs4_d_automount, |
71 | .d_manage = autofs4_d_manage, | |
72 | .d_release = autofs4_dentry_release, | |
73 | }; | |
74 | ||
4f8427d1 IK |
75 | static void autofs4_add_active(struct dentry *dentry) |
76 | { | |
77 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); | |
78 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
79 | if (ino) { | |
80 | spin_lock(&sbi->lookup_lock); | |
81 | if (!ino->active_count) { | |
82 | if (list_empty(&ino->active)) | |
83 | list_add(&ino->active, &sbi->active_list); | |
84 | } | |
85 | ino->active_count++; | |
86 | spin_unlock(&sbi->lookup_lock); | |
87 | } | |
88 | return; | |
89 | } | |
90 | ||
91 | static void autofs4_del_active(struct dentry *dentry) | |
92 | { | |
93 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); | |
94 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
95 | if (ino) { | |
96 | spin_lock(&sbi->lookup_lock); | |
97 | ino->active_count--; | |
98 | if (!ino->active_count) { | |
99 | if (!list_empty(&ino->active)) | |
100 | list_del_init(&ino->active); | |
101 | } | |
102 | spin_unlock(&sbi->lookup_lock); | |
103 | } | |
104 | return; | |
105 | } | |
106 | ||
1da177e4 LT |
107 | static int autofs4_dir_open(struct inode *inode, struct file *file) |
108 | { | |
a4669ed8 | 109 | struct dentry *dentry = file->f_path.dentry; |
1da177e4 | 110 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); |
f360ce3b | 111 | |
1da177e4 LT |
112 | DPRINTK("file=%p dentry=%p %.*s", |
113 | file, dentry, dentry->d_name.len, dentry->d_name.name); | |
114 | ||
115 | if (autofs4_oz_mode(sbi)) | |
116 | goto out; | |
117 | ||
ff9cd499 IK |
118 | /* |
119 | * An empty directory in an autofs file system is always a | |
120 | * mount point. The daemon must have failed to mount this | |
121 | * during lookup so it doesn't exist. This can happen, for | |
122 | * example, if user space returns an incorrect status for a | |
123 | * mount request. Otherwise we're doing a readdir on the | |
124 | * autofs file system so just let the libfs routines handle | |
125 | * it. | |
126 | */ | |
b5c84bf6 | 127 | spin_lock(&autofs4_lock); |
2fd6b7f5 | 128 | spin_lock(&dentry->d_lock); |
c42c7f7e | 129 | if (!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) { |
2fd6b7f5 | 130 | spin_unlock(&dentry->d_lock); |
b5c84bf6 | 131 | spin_unlock(&autofs4_lock); |
ff9cd499 | 132 | return -ENOENT; |
1da177e4 | 133 | } |
2fd6b7f5 | 134 | spin_unlock(&dentry->d_lock); |
b5c84bf6 | 135 | spin_unlock(&autofs4_lock); |
1da177e4 | 136 | |
1da177e4 | 137 | out: |
ff9cd499 | 138 | return dcache_dir_open(inode, file); |
1da177e4 LT |
139 | } |
140 | ||
34ca959c | 141 | void autofs4_dentry_release(struct dentry *de) |
1da177e4 LT |
142 | { |
143 | struct autofs_info *inf; | |
144 | ||
145 | DPRINTK("releasing %p", de); | |
146 | ||
147 | inf = autofs4_dentry_ino(de); | |
1da177e4 | 148 | if (inf) { |
f50b6f86 | 149 | struct autofs_sb_info *sbi = autofs4_sbi(de->d_sb); |
f50b6f86 | 150 | if (sbi) { |
5f6f4f28 | 151 | spin_lock(&sbi->lookup_lock); |
25767378 IK |
152 | if (!list_empty(&inf->active)) |
153 | list_del(&inf->active); | |
5f6f4f28 IK |
154 | if (!list_empty(&inf->expiring)) |
155 | list_del(&inf->expiring); | |
156 | spin_unlock(&sbi->lookup_lock); | |
f50b6f86 | 157 | } |
1da177e4 LT |
158 | autofs4_free_ino(inf); |
159 | } | |
160 | } | |
161 | ||
6510c9d8 | 162 | static struct dentry *autofs4_lookup_active(struct dentry *dentry) |
25767378 | 163 | { |
6510c9d8 IK |
164 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); |
165 | struct dentry *parent = dentry->d_parent; | |
166 | struct qstr *name = &dentry->d_name; | |
25767378 IK |
167 | unsigned int len = name->len; |
168 | unsigned int hash = name->hash; | |
169 | const unsigned char *str = name->name; | |
170 | struct list_head *p, *head; | |
171 | ||
b5c84bf6 | 172 | spin_lock(&autofs4_lock); |
25767378 IK |
173 | spin_lock(&sbi->lookup_lock); |
174 | head = &sbi->active_list; | |
175 | list_for_each(p, head) { | |
176 | struct autofs_info *ino; | |
e4d5ade7 | 177 | struct dentry *active; |
25767378 IK |
178 | struct qstr *qstr; |
179 | ||
180 | ino = list_entry(p, struct autofs_info, active); | |
e4d5ade7 | 181 | active = ino->dentry; |
25767378 | 182 | |
e4d5ade7 | 183 | spin_lock(&active->d_lock); |
25767378 IK |
184 | |
185 | /* Already gone? */ | |
b7ab39f6 | 186 | if (active->d_count == 0) |
25767378 IK |
187 | goto next; |
188 | ||
e4d5ade7 | 189 | qstr = &active->d_name; |
25767378 | 190 | |
e4d5ade7 | 191 | if (active->d_name.hash != hash) |
25767378 | 192 | goto next; |
e4d5ade7 | 193 | if (active->d_parent != parent) |
25767378 IK |
194 | goto next; |
195 | ||
196 | if (qstr->len != len) | |
197 | goto next; | |
198 | if (memcmp(qstr->name, str, len)) | |
199 | goto next; | |
200 | ||
4b1ae27a | 201 | if (d_unhashed(active)) { |
b7ab39f6 | 202 | dget_dlock(active); |
4b1ae27a AV |
203 | spin_unlock(&active->d_lock); |
204 | spin_unlock(&sbi->lookup_lock); | |
b5c84bf6 | 205 | spin_unlock(&autofs4_lock); |
4b1ae27a AV |
206 | return active; |
207 | } | |
25767378 | 208 | next: |
e4d5ade7 | 209 | spin_unlock(&active->d_lock); |
25767378 IK |
210 | } |
211 | spin_unlock(&sbi->lookup_lock); | |
b5c84bf6 | 212 | spin_unlock(&autofs4_lock); |
25767378 IK |
213 | |
214 | return NULL; | |
215 | } | |
216 | ||
6510c9d8 | 217 | static struct dentry *autofs4_lookup_expiring(struct dentry *dentry) |
f50b6f86 | 218 | { |
6510c9d8 IK |
219 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); |
220 | struct dentry *parent = dentry->d_parent; | |
221 | struct qstr *name = &dentry->d_name; | |
f50b6f86 IK |
222 | unsigned int len = name->len; |
223 | unsigned int hash = name->hash; | |
224 | const unsigned char *str = name->name; | |
225 | struct list_head *p, *head; | |
226 | ||
b5c84bf6 | 227 | spin_lock(&autofs4_lock); |
5f6f4f28 IK |
228 | spin_lock(&sbi->lookup_lock); |
229 | head = &sbi->expiring_list; | |
f50b6f86 IK |
230 | list_for_each(p, head) { |
231 | struct autofs_info *ino; | |
cb4b492a | 232 | struct dentry *expiring; |
f50b6f86 IK |
233 | struct qstr *qstr; |
234 | ||
5f6f4f28 | 235 | ino = list_entry(p, struct autofs_info, expiring); |
cb4b492a | 236 | expiring = ino->dentry; |
f50b6f86 | 237 | |
cb4b492a | 238 | spin_lock(&expiring->d_lock); |
f50b6f86 IK |
239 | |
240 | /* Bad luck, we've already been dentry_iput */ | |
cb4b492a | 241 | if (!expiring->d_inode) |
f50b6f86 IK |
242 | goto next; |
243 | ||
cb4b492a | 244 | qstr = &expiring->d_name; |
f50b6f86 | 245 | |
cb4b492a | 246 | if (expiring->d_name.hash != hash) |
f50b6f86 | 247 | goto next; |
cb4b492a | 248 | if (expiring->d_parent != parent) |
f50b6f86 IK |
249 | goto next; |
250 | ||
251 | if (qstr->len != len) | |
252 | goto next; | |
253 | if (memcmp(qstr->name, str, len)) | |
254 | goto next; | |
255 | ||
4b1ae27a | 256 | if (d_unhashed(expiring)) { |
b7ab39f6 | 257 | dget_dlock(expiring); |
4b1ae27a AV |
258 | spin_unlock(&expiring->d_lock); |
259 | spin_unlock(&sbi->lookup_lock); | |
b5c84bf6 | 260 | spin_unlock(&autofs4_lock); |
4b1ae27a AV |
261 | return expiring; |
262 | } | |
f50b6f86 | 263 | next: |
cb4b492a | 264 | spin_unlock(&expiring->d_lock); |
f50b6f86 | 265 | } |
5f6f4f28 | 266 | spin_unlock(&sbi->lookup_lock); |
b5c84bf6 | 267 | spin_unlock(&autofs4_lock); |
f50b6f86 IK |
268 | |
269 | return NULL; | |
270 | } | |
271 | ||
10584211 IK |
272 | static int autofs4_mount_wait(struct dentry *dentry) |
273 | { | |
274 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); | |
275 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
276 | int status; | |
277 | ||
278 | if (ino->flags & AUTOFS_INF_PENDING) { | |
279 | DPRINTK("waiting for mount name=%.*s", | |
280 | dentry->d_name.len, dentry->d_name.name); | |
281 | status = autofs4_wait(sbi, dentry, NFY_MOUNT); | |
282 | DPRINTK("mount wait done status=%d", status); | |
283 | ino->last_used = jiffies; | |
284 | return status; | |
285 | } | |
286 | return 0; | |
287 | } | |
288 | ||
289 | static int do_expire_wait(struct dentry *dentry) | |
290 | { | |
291 | struct dentry *expiring; | |
292 | ||
293 | expiring = autofs4_lookup_expiring(dentry); | |
294 | if (!expiring) | |
295 | return autofs4_expire_wait(dentry); | |
296 | else { | |
297 | /* | |
298 | * If we are racing with expire the request might not | |
299 | * be quite complete, but the directory has been removed | |
300 | * so it must have been successful, just wait for it. | |
301 | */ | |
302 | autofs4_expire_wait(expiring); | |
303 | autofs4_del_expiring(expiring); | |
304 | dput(expiring); | |
305 | } | |
306 | return 0; | |
307 | } | |
308 | ||
309 | static struct dentry *autofs4_mountpoint_changed(struct path *path) | |
310 | { | |
311 | struct dentry *dentry = path->dentry; | |
312 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); | |
313 | ||
314 | /* | |
315 | * If this is an indirect mount the dentry could have gone away | |
316 | * as a result of an expire and a new one created. | |
317 | */ | |
318 | if (autofs_type_indirect(sbi->type) && d_unhashed(dentry)) { | |
319 | struct dentry *parent = dentry->d_parent; | |
320 | struct dentry *new = d_lookup(parent, &dentry->d_name); | |
321 | if (!new) | |
322 | return NULL; | |
323 | dput(path->dentry); | |
324 | path->dentry = new; | |
325 | } | |
326 | return path->dentry; | |
327 | } | |
328 | ||
71e469db | 329 | static struct vfsmount *autofs4_d_automount(struct path *path) |
10584211 IK |
330 | { |
331 | struct dentry *dentry = path->dentry; | |
332 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); | |
333 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
334 | int status; | |
335 | ||
336 | DPRINTK("dentry=%p %.*s", | |
337 | dentry, dentry->d_name.len, dentry->d_name.name); | |
338 | ||
b5b80177 IK |
339 | /* |
340 | * Someone may have manually umounted this or it was a submount | |
341 | * that has gone away. | |
342 | */ | |
343 | spin_lock(&dentry->d_lock); | |
344 | if (!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) { | |
345 | if (!(dentry->d_flags & DCACHE_MANAGE_TRANSIT) && | |
346 | (dentry->d_flags & DCACHE_NEED_AUTOMOUNT)) | |
347 | __managed_dentry_set_transit(path->dentry); | |
348 | } | |
349 | spin_unlock(&dentry->d_lock); | |
350 | ||
10584211 IK |
351 | /* The daemon never triggers a mount. */ |
352 | if (autofs4_oz_mode(sbi)) | |
353 | return NULL; | |
354 | ||
355 | /* | |
356 | * If an expire request is pending everyone must wait. | |
357 | * If the expire fails we're still mounted so continue | |
358 | * the follow and return. A return of -EAGAIN (which only | |
359 | * happens with indirect mounts) means the expire completed | |
360 | * and the directory was removed, so just go ahead and try | |
361 | * the mount. | |
362 | */ | |
363 | status = do_expire_wait(dentry); | |
364 | if (status && status != -EAGAIN) | |
365 | return NULL; | |
366 | ||
367 | /* Callback to the daemon to perform the mount or wait */ | |
368 | spin_lock(&sbi->fs_lock); | |
369 | if (ino->flags & AUTOFS_INF_PENDING) { | |
370 | spin_unlock(&sbi->fs_lock); | |
371 | status = autofs4_mount_wait(dentry); | |
372 | if (status) | |
373 | return ERR_PTR(status); | |
374 | spin_lock(&sbi->fs_lock); | |
375 | goto done; | |
376 | } | |
377 | ||
378 | /* | |
379 | * If the dentry is a symlink it's equivalent to a directory | |
b5b80177 | 380 | * having d_mountpoint() true, so there's no need to call back |
10584211 IK |
381 | * to the daemon. |
382 | */ | |
383 | if (dentry->d_inode && S_ISLNK(dentry->d_inode->i_mode)) | |
384 | goto done; | |
b5b80177 IK |
385 | if (!d_mountpoint(dentry)) { |
386 | /* | |
387 | * It's possible that user space hasn't removed directories | |
388 | * after umounting a rootless multi-mount, although it | |
389 | * should. For v5 have_submounts() is sufficient to handle | |
390 | * this because the leaves of the directory tree under the | |
391 | * mount never trigger mounts themselves (they have an autofs | |
392 | * trigger mount mounted on them). But v4 pseudo direct mounts | |
393 | * do need the leaves to to trigger mounts. In this case we | |
394 | * have no choice but to use the list_empty() check and | |
395 | * require user space behave. | |
396 | */ | |
397 | if (sbi->version > 4) { | |
398 | if (have_submounts(dentry)) | |
399 | goto done; | |
400 | } else { | |
401 | spin_lock(&dentry->d_lock); | |
402 | if (!list_empty(&dentry->d_subdirs)) { | |
403 | spin_unlock(&dentry->d_lock); | |
404 | goto done; | |
405 | } | |
406 | spin_unlock(&dentry->d_lock); | |
407 | } | |
10584211 | 408 | ino->flags |= AUTOFS_INF_PENDING; |
10584211 IK |
409 | spin_unlock(&sbi->fs_lock); |
410 | status = autofs4_mount_wait(dentry); | |
411 | if (status) | |
412 | return ERR_PTR(status); | |
413 | spin_lock(&sbi->fs_lock); | |
414 | ino->flags &= ~AUTOFS_INF_PENDING; | |
10584211 | 415 | } |
10584211 | 416 | done: |
b5b80177 IK |
417 | if (!(ino->flags & AUTOFS_INF_EXPIRING)) { |
418 | /* | |
419 | * Any needed mounting has been completed and the path updated | |
420 | * so turn this into a normal dentry so we don't continually | |
421 | * call ->d_automount() and ->d_manage(). | |
422 | */ | |
423 | spin_lock(&dentry->d_lock); | |
424 | __managed_dentry_clear_transit(dentry); | |
425 | /* | |
426 | * Only clear DMANAGED_AUTOMOUNT for rootless multi-mounts and | |
427 | * symlinks as in all other cases the dentry will be covered by | |
428 | * an actual mount so ->d_automount() won't be called during | |
429 | * the follow. | |
430 | */ | |
431 | if ((!d_mountpoint(dentry) && | |
432 | !list_empty(&dentry->d_subdirs)) || | |
433 | (dentry->d_inode && S_ISLNK(dentry->d_inode->i_mode))) | |
434 | __managed_dentry_clear_automount(dentry); | |
435 | spin_unlock(&dentry->d_lock); | |
436 | } | |
10584211 IK |
437 | spin_unlock(&sbi->fs_lock); |
438 | ||
439 | /* Mount succeeded, check if we ended up with a new dentry */ | |
440 | dentry = autofs4_mountpoint_changed(path); | |
441 | if (!dentry) | |
442 | return ERR_PTR(-ENOENT); | |
443 | ||
444 | return NULL; | |
445 | } | |
446 | ||
ab90911f | 447 | int autofs4_d_manage(struct dentry *dentry, bool mounting_here, bool rcu_walk) |
b5b80177 IK |
448 | { |
449 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); | |
450 | ||
451 | DPRINTK("dentry=%p %.*s", | |
452 | dentry, dentry->d_name.len, dentry->d_name.name); | |
453 | ||
454 | /* The daemon never waits. */ | |
455 | if (autofs4_oz_mode(sbi) || mounting_here) { | |
456 | if (!d_mountpoint(dentry)) | |
457 | return -EISDIR; | |
458 | return 0; | |
459 | } | |
460 | ||
ab90911f DH |
461 | /* We need to sleep, so we need pathwalk to be in ref-mode */ |
462 | if (rcu_walk) | |
463 | return -ECHILD; | |
464 | ||
b5b80177 IK |
465 | /* Wait for pending expires */ |
466 | do_expire_wait(dentry); | |
467 | ||
468 | /* | |
469 | * This dentry may be under construction so wait on mount | |
470 | * completion. | |
471 | */ | |
472 | return autofs4_mount_wait(dentry); | |
473 | } | |
474 | ||
1da177e4 LT |
475 | /* Lookups in the root directory */ |
476 | static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) | |
477 | { | |
478 | struct autofs_sb_info *sbi; | |
25767378 | 479 | struct autofs_info *ino; |
10584211 | 480 | struct dentry *active; |
1da177e4 | 481 | |
10584211 | 482 | DPRINTK("name = %.*s", dentry->d_name.len, dentry->d_name.name); |
1da177e4 | 483 | |
718c604a | 484 | /* File name too long to exist */ |
1da177e4 | 485 | if (dentry->d_name.len > NAME_MAX) |
718c604a | 486 | return ERR_PTR(-ENAMETOOLONG); |
1da177e4 LT |
487 | |
488 | sbi = autofs4_sbi(dir->i_sb); | |
718c604a | 489 | |
1da177e4 | 490 | DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d", |
c0bcc9d5 IK |
491 | current->pid, task_pgrp_nr(current), sbi->catatonic, |
492 | autofs4_oz_mode(sbi)); | |
1da177e4 | 493 | |
6510c9d8 | 494 | active = autofs4_lookup_active(dentry); |
90387c9c | 495 | if (active) { |
10584211 | 496 | return active; |
aa952eb2 | 497 | } else { |
4b1ae27a | 498 | /* |
10584211 IK |
499 | * A dentry that is not within the root can never trigger a |
500 | * mount operation, unless the directory already exists, so we | |
501 | * can return fail immediately. The daemon however does need | |
502 | * to create directories within the file system. | |
4b1ae27a | 503 | */ |
10584211 IK |
504 | if (!autofs4_oz_mode(sbi) && !IS_ROOT(dentry->d_parent)) |
505 | return ERR_PTR(-ENOENT); | |
506 | ||
507 | /* Mark entries in the root as mount triggers */ | |
b650c858 | 508 | if (autofs_type_indirect(sbi->type) && IS_ROOT(dentry->d_parent)) |
b5b80177 | 509 | __managed_dentry_set_managed(dentry); |
10584211 | 510 | |
09f12c03 | 511 | ino = autofs4_init_ino(NULL, sbi); |
4b1ae27a AV |
512 | if (!ino) |
513 | return ERR_PTR(-ENOMEM); | |
514 | ||
515 | dentry->d_fsdata = ino; | |
516 | ino->dentry = dentry; | |
5f6f4f28 | 517 | |
4b1ae27a AV |
518 | autofs4_add_active(dentry); |
519 | ||
520 | d_instantiate(dentry, NULL); | |
521 | } | |
1da177e4 LT |
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); | |
1aff3c8b | 531 | struct autofs_info *p_ino; |
1da177e4 | 532 | struct inode *inode; |
0bf71d4d | 533 | size_t size = strlen(symname); |
1da177e4 LT |
534 | char *cp; |
535 | ||
536 | DPRINTK("%s <- %.*s", symname, | |
537 | dentry->d_name.len, dentry->d_name.name); | |
538 | ||
539 | if (!autofs4_oz_mode(sbi)) | |
540 | return -EACCES; | |
541 | ||
09f12c03 | 542 | ino = autofs4_init_ino(ino, sbi); |
25767378 IK |
543 | if (!ino) |
544 | return -ENOMEM; | |
1da177e4 | 545 | |
4b1ae27a AV |
546 | autofs4_del_active(dentry); |
547 | ||
0bf71d4d | 548 | cp = kmalloc(size + 1, GFP_KERNEL); |
25767378 IK |
549 | if (!cp) { |
550 | if (!dentry->d_fsdata) | |
551 | kfree(ino); | |
552 | return -ENOMEM; | |
1da177e4 LT |
553 | } |
554 | ||
555 | strcpy(cp, symname); | |
556 | ||
726a5e06 | 557 | inode = autofs4_get_inode(dir->i_sb, S_IFLNK | 0555); |
25767378 IK |
558 | if (!inode) { |
559 | kfree(cp); | |
560 | if (!dentry->d_fsdata) | |
561 | kfree(ino); | |
562 | return -ENOMEM; | |
563 | } | |
292c5ee8 | 564 | inode->i_private = cp; |
0bf71d4d | 565 | inode->i_size = size; |
1864f7bd | 566 | d_add(dentry, inode); |
1da177e4 | 567 | |
1da177e4 LT |
568 | dentry->d_fsdata = ino; |
569 | ino->dentry = dget(dentry); | |
1aff3c8b IK |
570 | atomic_inc(&ino->count); |
571 | p_ino = autofs4_dentry_ino(dentry->d_parent); | |
572 | if (p_ino && dentry->d_parent != dentry) | |
573 | atomic_inc(&p_ino->count); | |
1da177e4 LT |
574 | |
575 | dir->i_mtime = CURRENT_TIME; | |
576 | ||
577 | return 0; | |
578 | } | |
579 | ||
580 | /* | |
581 | * NOTE! | |
582 | * | |
583 | * Normal filesystems would do a "d_delete()" to tell the VFS dcache | |
584 | * that the file no longer exists. However, doing that means that the | |
585 | * VFS layer can turn the dentry into a negative dentry. We don't want | |
f50b6f86 | 586 | * this, because the unlink is probably the result of an expire. |
5f6f4f28 IK |
587 | * We simply d_drop it and add it to a expiring list in the super block, |
588 | * which allows the dentry lookup to check for an incomplete expire. | |
1da177e4 LT |
589 | * |
590 | * If a process is blocked on the dentry waiting for the expire to finish, | |
591 | * it will invalidate the dentry and try to mount with a new one. | |
592 | * | |
593 | * Also see autofs4_dir_rmdir().. | |
594 | */ | |
595 | static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry) | |
596 | { | |
597 | struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); | |
598 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
1aff3c8b | 599 | struct autofs_info *p_ino; |
1da177e4 LT |
600 | |
601 | /* This allows root to remove symlinks */ | |
d78e53c8 | 602 | if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN)) |
1da177e4 LT |
603 | return -EACCES; |
604 | ||
1aff3c8b IK |
605 | if (atomic_dec_and_test(&ino->count)) { |
606 | p_ino = autofs4_dentry_ino(dentry->d_parent); | |
607 | if (p_ino && dentry->d_parent != dentry) | |
608 | atomic_dec(&p_ino->count); | |
609 | } | |
1da177e4 LT |
610 | dput(ino->dentry); |
611 | ||
612 | dentry->d_inode->i_size = 0; | |
ce71ec36 | 613 | clear_nlink(dentry->d_inode); |
1da177e4 LT |
614 | |
615 | dir->i_mtime = CURRENT_TIME; | |
616 | ||
b5c84bf6 | 617 | spin_lock(&autofs4_lock); |
4b1ae27a | 618 | autofs4_add_expiring(dentry); |
f50b6f86 IK |
619 | spin_lock(&dentry->d_lock); |
620 | __d_drop(dentry); | |
621 | spin_unlock(&dentry->d_lock); | |
b5c84bf6 | 622 | spin_unlock(&autofs4_lock); |
1da177e4 LT |
623 | |
624 | return 0; | |
625 | } | |
626 | ||
dd89f90d IK |
627 | /* |
628 | * Version 4 of autofs provides a pseudo direct mount implementation | |
629 | * that relies on directories at the leaves of a directory tree under | |
630 | * an indirect mount to trigger mounts. To allow for this we need to | |
631 | * set the DMANAGED_AUTOMOUNT and DMANAGED_TRANSIT flags on the leaves | |
632 | * of the directory tree. There is no need to clear the automount flag | |
633 | * following a mount or restore it after an expire because these mounts | |
634 | * are always covered. However, it is neccessary to ensure that these | |
635 | * flags are clear on non-empty directories to avoid unnecessary calls | |
636 | * during path walks. | |
637 | */ | |
638 | static void autofs_set_leaf_automount_flags(struct dentry *dentry) | |
639 | { | |
640 | struct dentry *parent; | |
641 | ||
642 | /* root and dentrys in the root are already handled */ | |
643 | if (IS_ROOT(dentry->d_parent)) | |
644 | return; | |
645 | ||
646 | managed_dentry_set_managed(dentry); | |
647 | ||
648 | parent = dentry->d_parent; | |
649 | /* only consider parents below dentrys in the root */ | |
650 | if (IS_ROOT(parent->d_parent)) | |
651 | return; | |
652 | managed_dentry_clear_managed(parent); | |
653 | return; | |
654 | } | |
655 | ||
656 | static void autofs_clear_leaf_automount_flags(struct dentry *dentry) | |
657 | { | |
658 | struct list_head *d_child; | |
659 | struct dentry *parent; | |
660 | ||
661 | /* flags for dentrys in the root are handled elsewhere */ | |
662 | if (IS_ROOT(dentry->d_parent)) | |
663 | return; | |
664 | ||
665 | managed_dentry_clear_managed(dentry); | |
666 | ||
667 | parent = dentry->d_parent; | |
668 | /* only consider parents below dentrys in the root */ | |
669 | if (IS_ROOT(parent->d_parent)) | |
670 | return; | |
671 | d_child = &dentry->d_u.d_child; | |
672 | /* Set parent managed if it's becoming empty */ | |
673 | if (d_child->next == &parent->d_subdirs && | |
674 | d_child->prev == &parent->d_subdirs) | |
675 | managed_dentry_set_managed(parent); | |
676 | return; | |
677 | } | |
678 | ||
1da177e4 LT |
679 | static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry) |
680 | { | |
681 | struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); | |
682 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
1aff3c8b | 683 | struct autofs_info *p_ino; |
1da177e4 | 684 | |
f50b6f86 IK |
685 | DPRINTK("dentry %p, removing %.*s", |
686 | dentry, dentry->d_name.len, dentry->d_name.name); | |
687 | ||
1da177e4 LT |
688 | if (!autofs4_oz_mode(sbi)) |
689 | return -EACCES; | |
690 | ||
b5c84bf6 | 691 | spin_lock(&autofs4_lock); |
2fd6b7f5 NP |
692 | spin_lock(&sbi->lookup_lock); |
693 | spin_lock(&dentry->d_lock); | |
1da177e4 | 694 | if (!list_empty(&dentry->d_subdirs)) { |
2fd6b7f5 NP |
695 | spin_unlock(&dentry->d_lock); |
696 | spin_unlock(&sbi->lookup_lock); | |
b5c84bf6 | 697 | spin_unlock(&autofs4_lock); |
1da177e4 LT |
698 | return -ENOTEMPTY; |
699 | } | |
2fd6b7f5 NP |
700 | __autofs4_add_expiring(dentry); |
701 | spin_unlock(&sbi->lookup_lock); | |
1da177e4 LT |
702 | __d_drop(dentry); |
703 | spin_unlock(&dentry->d_lock); | |
b5c84bf6 | 704 | spin_unlock(&autofs4_lock); |
1da177e4 | 705 | |
dd89f90d IK |
706 | if (sbi->version < 5) |
707 | autofs_clear_leaf_automount_flags(dentry); | |
708 | ||
1aff3c8b IK |
709 | if (atomic_dec_and_test(&ino->count)) { |
710 | p_ino = autofs4_dentry_ino(dentry->d_parent); | |
711 | if (p_ino && dentry->d_parent != dentry) | |
712 | atomic_dec(&p_ino->count); | |
713 | } | |
1da177e4 | 714 | dput(ino->dentry); |
1da177e4 | 715 | dentry->d_inode->i_size = 0; |
ce71ec36 | 716 | clear_nlink(dentry->d_inode); |
1da177e4 LT |
717 | |
718 | if (dir->i_nlink) | |
9a53c3a7 | 719 | drop_nlink(dir); |
1da177e4 LT |
720 | |
721 | return 0; | |
722 | } | |
723 | ||
724 | static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
725 | { | |
726 | struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); | |
727 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
1aff3c8b | 728 | struct autofs_info *p_ino; |
1da177e4 LT |
729 | struct inode *inode; |
730 | ||
d78e53c8 | 731 | if (!autofs4_oz_mode(sbi)) |
1da177e4 LT |
732 | return -EACCES; |
733 | ||
734 | DPRINTK("dentry %p, creating %.*s", | |
735 | dentry, dentry->d_name.len, dentry->d_name.name); | |
736 | ||
09f12c03 | 737 | ino = autofs4_init_ino(ino, sbi); |
25767378 IK |
738 | if (!ino) |
739 | return -ENOMEM; | |
740 | ||
4b1ae27a AV |
741 | autofs4_del_active(dentry); |
742 | ||
726a5e06 | 743 | inode = autofs4_get_inode(dir->i_sb, S_IFDIR | 0555); |
25767378 IK |
744 | if (!inode) { |
745 | if (!dentry->d_fsdata) | |
746 | kfree(ino); | |
747 | return -ENOMEM; | |
748 | } | |
1864f7bd | 749 | d_add(dentry, inode); |
1da177e4 | 750 | |
dd89f90d IK |
751 | if (sbi->version < 5) |
752 | autofs_set_leaf_automount_flags(dentry); | |
753 | ||
1da177e4 LT |
754 | dentry->d_fsdata = ino; |
755 | ino->dentry = dget(dentry); | |
1aff3c8b IK |
756 | atomic_inc(&ino->count); |
757 | p_ino = autofs4_dentry_ino(dentry->d_parent); | |
758 | if (p_ino && dentry->d_parent != dentry) | |
759 | atomic_inc(&p_ino->count); | |
d8c76e6f | 760 | inc_nlink(dir); |
1da177e4 LT |
761 | dir->i_mtime = CURRENT_TIME; |
762 | ||
763 | return 0; | |
764 | } | |
765 | ||
766 | /* Get/set timeout ioctl() operation */ | |
c9243f5b AB |
767 | #ifdef CONFIG_COMPAT |
768 | static inline int autofs4_compat_get_set_timeout(struct autofs_sb_info *sbi, | |
769 | compat_ulong_t __user *p) | |
770 | { | |
771 | int rv; | |
772 | unsigned long ntimeout; | |
773 | ||
774 | if ((rv = get_user(ntimeout, p)) || | |
775 | (rv = put_user(sbi->exp_timeout/HZ, p))) | |
776 | return rv; | |
777 | ||
778 | if (ntimeout > UINT_MAX/HZ) | |
779 | sbi->exp_timeout = 0; | |
780 | else | |
781 | sbi->exp_timeout = ntimeout * HZ; | |
782 | ||
783 | return 0; | |
784 | } | |
785 | #endif | |
786 | ||
1da177e4 LT |
787 | static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi, |
788 | unsigned long __user *p) | |
789 | { | |
790 | int rv; | |
791 | unsigned long ntimeout; | |
792 | ||
d78e53c8 SB |
793 | if ((rv = get_user(ntimeout, p)) || |
794 | (rv = put_user(sbi->exp_timeout/HZ, p))) | |
1da177e4 LT |
795 | return rv; |
796 | ||
d78e53c8 | 797 | if (ntimeout > ULONG_MAX/HZ) |
1da177e4 LT |
798 | sbi->exp_timeout = 0; |
799 | else | |
800 | sbi->exp_timeout = ntimeout * HZ; | |
801 | ||
802 | return 0; | |
803 | } | |
804 | ||
805 | /* Return protocol version */ | |
806 | static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int __user *p) | |
807 | { | |
808 | return put_user(sbi->version, p); | |
809 | } | |
810 | ||
811 | /* Return protocol sub version */ | |
812 | static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p) | |
813 | { | |
814 | return put_user(sbi->sub_version, p); | |
815 | } | |
816 | ||
1da177e4 LT |
817 | /* |
818 | * Tells the daemon whether it can umount the autofs mount. | |
819 | */ | |
820 | static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p) | |
821 | { | |
822 | int status = 0; | |
823 | ||
e3474a8e | 824 | if (may_umount(mnt)) |
1da177e4 LT |
825 | status = 1; |
826 | ||
827 | DPRINTK("returning %d", status); | |
828 | ||
829 | status = put_user(status, p); | |
830 | ||
831 | return status; | |
832 | } | |
833 | ||
834 | /* Identify autofs4_dentries - this is so we can tell if there's | |
835 | an extra dentry refcount or not. We only hold a refcount on the | |
836 | dentry if its non-negative (ie, d_inode != NULL) | |
837 | */ | |
838 | int is_autofs4_dentry(struct dentry *dentry) | |
839 | { | |
840 | return dentry && dentry->d_inode && | |
b650c858 | 841 | dentry->d_op == &autofs4_dentry_operations && |
1da177e4 LT |
842 | dentry->d_fsdata != NULL; |
843 | } | |
844 | ||
845 | /* | |
846 | * ioctl()'s on the root directory is the chief method for the daemon to | |
847 | * generate kernel reactions | |
848 | */ | |
3663df70 FW |
849 | static int autofs4_root_ioctl_unlocked(struct inode *inode, struct file *filp, |
850 | unsigned int cmd, unsigned long arg) | |
1da177e4 LT |
851 | { |
852 | struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb); | |
853 | void __user *p = (void __user *)arg; | |
854 | ||
855 | DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u", | |
a47afb0f | 856 | cmd,arg,sbi,task_pgrp_nr(current)); |
1da177e4 | 857 | |
d78e53c8 SB |
858 | if (_IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) || |
859 | _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT) | |
1da177e4 LT |
860 | return -ENOTTY; |
861 | ||
d78e53c8 | 862 | if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN)) |
1da177e4 LT |
863 | return -EPERM; |
864 | ||
865 | switch(cmd) { | |
866 | case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */ | |
867 | return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0); | |
868 | case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */ | |
869 | return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT); | |
870 | case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */ | |
871 | autofs4_catatonic_mode(sbi); | |
872 | return 0; | |
873 | case AUTOFS_IOC_PROTOVER: /* Get protocol version */ | |
874 | return autofs4_get_protover(sbi, p); | |
875 | case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */ | |
876 | return autofs4_get_protosubver(sbi, p); | |
877 | case AUTOFS_IOC_SETTIMEOUT: | |
878 | return autofs4_get_set_timeout(sbi, p); | |
c9243f5b AB |
879 | #ifdef CONFIG_COMPAT |
880 | case AUTOFS_IOC_SETTIMEOUT32: | |
881 | return autofs4_compat_get_set_timeout(sbi, p); | |
882 | #endif | |
1da177e4 | 883 | |
1da177e4 | 884 | case AUTOFS_IOC_ASKUMOUNT: |
a4669ed8 | 885 | return autofs4_ask_umount(filp->f_path.mnt, p); |
1da177e4 LT |
886 | |
887 | /* return a single thing to expire */ | |
888 | case AUTOFS_IOC_EXPIRE: | |
a4669ed8 | 889 | return autofs4_expire_run(inode->i_sb,filp->f_path.mnt,sbi, p); |
1da177e4 LT |
890 | /* same as above, but can send multiple expires through pipe */ |
891 | case AUTOFS_IOC_EXPIRE_MULTI: | |
a4669ed8 | 892 | return autofs4_expire_multi(inode->i_sb,filp->f_path.mnt,sbi, p); |
1da177e4 LT |
893 | |
894 | default: | |
895 | return -ENOSYS; | |
896 | } | |
897 | } | |
3663df70 FW |
898 | |
899 | static long autofs4_root_ioctl(struct file *filp, | |
900 | unsigned int cmd, unsigned long arg) | |
901 | { | |
3663df70 | 902 | struct inode *inode = filp->f_dentry->d_inode; |
de47de74 | 903 | return autofs4_root_ioctl_unlocked(inode, filp, cmd, arg); |
3663df70 | 904 | } |
c9243f5b AB |
905 | |
906 | #ifdef CONFIG_COMPAT | |
907 | static long autofs4_root_compat_ioctl(struct file *filp, | |
908 | unsigned int cmd, unsigned long arg) | |
909 | { | |
910 | struct inode *inode = filp->f_path.dentry->d_inode; | |
911 | int ret; | |
912 | ||
c9243f5b AB |
913 | if (cmd == AUTOFS_IOC_READY || cmd == AUTOFS_IOC_FAIL) |
914 | ret = autofs4_root_ioctl_unlocked(inode, filp, cmd, arg); | |
915 | else | |
916 | ret = autofs4_root_ioctl_unlocked(inode, filp, cmd, | |
917 | (unsigned long)compat_ptr(arg)); | |
c9243f5b AB |
918 | |
919 | return ret; | |
920 | } | |
921 | #endif |