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); |
b89b12b4 | 40 | static void autofs4_dentry_release(struct dentry *); |
1da177e4 | 41 | |
4b6f5d20 | 42 | const struct file_operations autofs4_root_operations = { |
1da177e4 LT |
43 | .open = dcache_dir_open, |
44 | .release = dcache_dir_close, | |
45 | .read = generic_read_dir, | |
aa55ddf3 | 46 | .readdir = dcache_readdir, |
59af1584 | 47 | .llseek = dcache_dir_lseek, |
3663df70 | 48 | .unlocked_ioctl = autofs4_root_ioctl, |
c9243f5b AB |
49 | #ifdef CONFIG_COMPAT |
50 | .compat_ioctl = autofs4_root_compat_ioctl, | |
51 | #endif | |
1da177e4 LT |
52 | }; |
53 | ||
4b6f5d20 | 54 | const struct file_operations autofs4_dir_operations = { |
1da177e4 | 55 | .open = autofs4_dir_open, |
ff9cd499 | 56 | .release = dcache_dir_close, |
1da177e4 | 57 | .read = generic_read_dir, |
ff9cd499 | 58 | .readdir = dcache_readdir, |
59af1584 | 59 | .llseek = dcache_dir_lseek, |
1da177e4 LT |
60 | }; |
61 | ||
754661f1 | 62 | const struct inode_operations autofs4_dir_inode_operations = { |
1da177e4 LT |
63 | .lookup = autofs4_lookup, |
64 | .unlink = autofs4_dir_unlink, | |
65 | .symlink = autofs4_dir_symlink, | |
66 | .mkdir = autofs4_dir_mkdir, | |
67 | .rmdir = autofs4_dir_rmdir, | |
68 | }; | |
69 | ||
71e469db | 70 | const struct dentry_operations autofs4_dentry_operations = { |
71e469db IK |
71 | .d_automount = autofs4_d_automount, |
72 | .d_manage = autofs4_d_manage, | |
73 | .d_release = autofs4_dentry_release, | |
74 | }; | |
75 | ||
4f8427d1 IK |
76 | static void autofs4_add_active(struct dentry *dentry) |
77 | { | |
78 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); | |
79 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
80 | if (ino) { | |
81 | spin_lock(&sbi->lookup_lock); | |
82 | if (!ino->active_count) { | |
83 | if (list_empty(&ino->active)) | |
84 | list_add(&ino->active, &sbi->active_list); | |
85 | } | |
86 | ino->active_count++; | |
87 | spin_unlock(&sbi->lookup_lock); | |
88 | } | |
89 | return; | |
90 | } | |
91 | ||
92 | static void autofs4_del_active(struct dentry *dentry) | |
93 | { | |
94 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); | |
95 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
96 | if (ino) { | |
97 | spin_lock(&sbi->lookup_lock); | |
98 | ino->active_count--; | |
99 | if (!ino->active_count) { | |
100 | if (!list_empty(&ino->active)) | |
101 | list_del_init(&ino->active); | |
102 | } | |
103 | spin_unlock(&sbi->lookup_lock); | |
104 | } | |
105 | return; | |
106 | } | |
107 | ||
1da177e4 LT |
108 | static int autofs4_dir_open(struct inode *inode, struct file *file) |
109 | { | |
a4669ed8 | 110 | struct dentry *dentry = file->f_path.dentry; |
1da177e4 | 111 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); |
f360ce3b | 112 | |
1da177e4 LT |
113 | DPRINTK("file=%p dentry=%p %.*s", |
114 | file, dentry, dentry->d_name.len, dentry->d_name.name); | |
115 | ||
116 | if (autofs4_oz_mode(sbi)) | |
117 | goto out; | |
118 | ||
ff9cd499 IK |
119 | /* |
120 | * An empty directory in an autofs file system is always a | |
121 | * mount point. The daemon must have failed to mount this | |
122 | * during lookup so it doesn't exist. This can happen, for | |
123 | * example, if user space returns an incorrect status for a | |
124 | * mount request. Otherwise we're doing a readdir on the | |
125 | * autofs file system so just let the libfs routines handle | |
126 | * it. | |
127 | */ | |
b5c84bf6 | 128 | spin_lock(&autofs4_lock); |
2fd6b7f5 | 129 | spin_lock(&dentry->d_lock); |
c42c7f7e | 130 | if (!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) { |
2fd6b7f5 | 131 | spin_unlock(&dentry->d_lock); |
b5c84bf6 | 132 | spin_unlock(&autofs4_lock); |
ff9cd499 | 133 | return -ENOENT; |
1da177e4 | 134 | } |
2fd6b7f5 | 135 | spin_unlock(&dentry->d_lock); |
b5c84bf6 | 136 | spin_unlock(&autofs4_lock); |
1da177e4 | 137 | |
1da177e4 | 138 | out: |
ff9cd499 | 139 | return dcache_dir_open(inode, file); |
1da177e4 LT |
140 | } |
141 | ||
b89b12b4 | 142 | static void autofs4_dentry_release(struct dentry *de) |
1da177e4 | 143 | { |
b89b12b4 AV |
144 | struct autofs_info *ino = autofs4_dentry_ino(de); |
145 | struct autofs_sb_info *sbi = autofs4_sbi(de->d_sb); | |
1da177e4 LT |
146 | |
147 | DPRINTK("releasing %p", de); | |
148 | ||
b89b12b4 AV |
149 | if (!ino) |
150 | return; | |
151 | ||
152 | if (sbi) { | |
153 | spin_lock(&sbi->lookup_lock); | |
154 | if (!list_empty(&ino->active)) | |
155 | list_del(&ino->active); | |
156 | if (!list_empty(&ino->expiring)) | |
157 | list_del(&ino->expiring); | |
158 | spin_unlock(&sbi->lookup_lock); | |
1da177e4 | 159 | } |
b89b12b4 AV |
160 | |
161 | autofs4_free_ino(ino); | |
1da177e4 LT |
162 | } |
163 | ||
6510c9d8 | 164 | static struct dentry *autofs4_lookup_active(struct dentry *dentry) |
25767378 | 165 | { |
6510c9d8 IK |
166 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); |
167 | struct dentry *parent = dentry->d_parent; | |
168 | struct qstr *name = &dentry->d_name; | |
25767378 IK |
169 | unsigned int len = name->len; |
170 | unsigned int hash = name->hash; | |
171 | const unsigned char *str = name->name; | |
172 | struct list_head *p, *head; | |
173 | ||
b5c84bf6 | 174 | spin_lock(&autofs4_lock); |
25767378 IK |
175 | spin_lock(&sbi->lookup_lock); |
176 | head = &sbi->active_list; | |
177 | list_for_each(p, head) { | |
178 | struct autofs_info *ino; | |
e4d5ade7 | 179 | struct dentry *active; |
25767378 IK |
180 | struct qstr *qstr; |
181 | ||
182 | ino = list_entry(p, struct autofs_info, active); | |
e4d5ade7 | 183 | active = ino->dentry; |
25767378 | 184 | |
e4d5ade7 | 185 | spin_lock(&active->d_lock); |
25767378 IK |
186 | |
187 | /* Already gone? */ | |
b7ab39f6 | 188 | if (active->d_count == 0) |
25767378 IK |
189 | goto next; |
190 | ||
e4d5ade7 | 191 | qstr = &active->d_name; |
25767378 | 192 | |
e4d5ade7 | 193 | if (active->d_name.hash != hash) |
25767378 | 194 | goto next; |
e4d5ade7 | 195 | if (active->d_parent != parent) |
25767378 IK |
196 | goto next; |
197 | ||
198 | if (qstr->len != len) | |
199 | goto next; | |
200 | if (memcmp(qstr->name, str, len)) | |
201 | goto next; | |
202 | ||
4b1ae27a | 203 | if (d_unhashed(active)) { |
b7ab39f6 | 204 | dget_dlock(active); |
4b1ae27a AV |
205 | spin_unlock(&active->d_lock); |
206 | spin_unlock(&sbi->lookup_lock); | |
b5c84bf6 | 207 | spin_unlock(&autofs4_lock); |
4b1ae27a AV |
208 | return active; |
209 | } | |
25767378 | 210 | next: |
e4d5ade7 | 211 | spin_unlock(&active->d_lock); |
25767378 IK |
212 | } |
213 | spin_unlock(&sbi->lookup_lock); | |
b5c84bf6 | 214 | spin_unlock(&autofs4_lock); |
25767378 IK |
215 | |
216 | return NULL; | |
217 | } | |
218 | ||
6510c9d8 | 219 | static struct dentry *autofs4_lookup_expiring(struct dentry *dentry) |
f50b6f86 | 220 | { |
6510c9d8 IK |
221 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); |
222 | struct dentry *parent = dentry->d_parent; | |
223 | struct qstr *name = &dentry->d_name; | |
f50b6f86 IK |
224 | unsigned int len = name->len; |
225 | unsigned int hash = name->hash; | |
226 | const unsigned char *str = name->name; | |
227 | struct list_head *p, *head; | |
228 | ||
b5c84bf6 | 229 | spin_lock(&autofs4_lock); |
5f6f4f28 IK |
230 | spin_lock(&sbi->lookup_lock); |
231 | head = &sbi->expiring_list; | |
f50b6f86 IK |
232 | list_for_each(p, head) { |
233 | struct autofs_info *ino; | |
cb4b492a | 234 | struct dentry *expiring; |
f50b6f86 IK |
235 | struct qstr *qstr; |
236 | ||
5f6f4f28 | 237 | ino = list_entry(p, struct autofs_info, expiring); |
cb4b492a | 238 | expiring = ino->dentry; |
f50b6f86 | 239 | |
cb4b492a | 240 | spin_lock(&expiring->d_lock); |
f50b6f86 IK |
241 | |
242 | /* Bad luck, we've already been dentry_iput */ | |
cb4b492a | 243 | if (!expiring->d_inode) |
f50b6f86 IK |
244 | goto next; |
245 | ||
cb4b492a | 246 | qstr = &expiring->d_name; |
f50b6f86 | 247 | |
cb4b492a | 248 | if (expiring->d_name.hash != hash) |
f50b6f86 | 249 | goto next; |
cb4b492a | 250 | if (expiring->d_parent != parent) |
f50b6f86 IK |
251 | goto next; |
252 | ||
253 | if (qstr->len != len) | |
254 | goto next; | |
255 | if (memcmp(qstr->name, str, len)) | |
256 | goto next; | |
257 | ||
4b1ae27a | 258 | if (d_unhashed(expiring)) { |
b7ab39f6 | 259 | dget_dlock(expiring); |
4b1ae27a AV |
260 | spin_unlock(&expiring->d_lock); |
261 | spin_unlock(&sbi->lookup_lock); | |
b5c84bf6 | 262 | spin_unlock(&autofs4_lock); |
4b1ae27a AV |
263 | return expiring; |
264 | } | |
f50b6f86 | 265 | next: |
cb4b492a | 266 | spin_unlock(&expiring->d_lock); |
f50b6f86 | 267 | } |
5f6f4f28 | 268 | spin_unlock(&sbi->lookup_lock); |
b5c84bf6 | 269 | spin_unlock(&autofs4_lock); |
f50b6f86 IK |
270 | |
271 | return NULL; | |
272 | } | |
273 | ||
10584211 IK |
274 | static int autofs4_mount_wait(struct dentry *dentry) |
275 | { | |
276 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); | |
277 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
278 | int status; | |
279 | ||
280 | if (ino->flags & AUTOFS_INF_PENDING) { | |
281 | DPRINTK("waiting for mount name=%.*s", | |
282 | dentry->d_name.len, dentry->d_name.name); | |
283 | status = autofs4_wait(sbi, dentry, NFY_MOUNT); | |
284 | DPRINTK("mount wait done status=%d", status); | |
285 | ino->last_used = jiffies; | |
286 | return status; | |
287 | } | |
288 | return 0; | |
289 | } | |
290 | ||
291 | static int do_expire_wait(struct dentry *dentry) | |
292 | { | |
293 | struct dentry *expiring; | |
294 | ||
295 | expiring = autofs4_lookup_expiring(dentry); | |
296 | if (!expiring) | |
297 | return autofs4_expire_wait(dentry); | |
298 | else { | |
299 | /* | |
300 | * If we are racing with expire the request might not | |
301 | * be quite complete, but the directory has been removed | |
302 | * so it must have been successful, just wait for it. | |
303 | */ | |
304 | autofs4_expire_wait(expiring); | |
305 | autofs4_del_expiring(expiring); | |
306 | dput(expiring); | |
307 | } | |
308 | return 0; | |
309 | } | |
310 | ||
311 | static struct dentry *autofs4_mountpoint_changed(struct path *path) | |
312 | { | |
313 | struct dentry *dentry = path->dentry; | |
314 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); | |
315 | ||
316 | /* | |
317 | * If this is an indirect mount the dentry could have gone away | |
318 | * as a result of an expire and a new one created. | |
319 | */ | |
320 | if (autofs_type_indirect(sbi->type) && d_unhashed(dentry)) { | |
321 | struct dentry *parent = dentry->d_parent; | |
322 | struct dentry *new = d_lookup(parent, &dentry->d_name); | |
323 | if (!new) | |
324 | return NULL; | |
325 | dput(path->dentry); | |
326 | path->dentry = new; | |
327 | } | |
328 | return path->dentry; | |
329 | } | |
330 | ||
71e469db | 331 | static struct vfsmount *autofs4_d_automount(struct path *path) |
10584211 IK |
332 | { |
333 | struct dentry *dentry = path->dentry; | |
334 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); | |
335 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
336 | int status; | |
337 | ||
338 | DPRINTK("dentry=%p %.*s", | |
339 | dentry, dentry->d_name.len, dentry->d_name.name); | |
340 | ||
b5b80177 IK |
341 | /* |
342 | * Someone may have manually umounted this or it was a submount | |
343 | * that has gone away. | |
344 | */ | |
345 | spin_lock(&dentry->d_lock); | |
346 | if (!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) { | |
347 | if (!(dentry->d_flags & DCACHE_MANAGE_TRANSIT) && | |
348 | (dentry->d_flags & DCACHE_NEED_AUTOMOUNT)) | |
349 | __managed_dentry_set_transit(path->dentry); | |
350 | } | |
351 | spin_unlock(&dentry->d_lock); | |
352 | ||
10584211 IK |
353 | /* The daemon never triggers a mount. */ |
354 | if (autofs4_oz_mode(sbi)) | |
355 | return NULL; | |
356 | ||
357 | /* | |
358 | * If an expire request is pending everyone must wait. | |
359 | * If the expire fails we're still mounted so continue | |
360 | * the follow and return. A return of -EAGAIN (which only | |
361 | * happens with indirect mounts) means the expire completed | |
362 | * and the directory was removed, so just go ahead and try | |
363 | * the mount. | |
364 | */ | |
365 | status = do_expire_wait(dentry); | |
366 | if (status && status != -EAGAIN) | |
367 | return NULL; | |
368 | ||
369 | /* Callback to the daemon to perform the mount or wait */ | |
370 | spin_lock(&sbi->fs_lock); | |
371 | if (ino->flags & AUTOFS_INF_PENDING) { | |
372 | spin_unlock(&sbi->fs_lock); | |
373 | status = autofs4_mount_wait(dentry); | |
374 | if (status) | |
375 | return ERR_PTR(status); | |
376 | spin_lock(&sbi->fs_lock); | |
377 | goto done; | |
378 | } | |
379 | ||
380 | /* | |
381 | * If the dentry is a symlink it's equivalent to a directory | |
b5b80177 | 382 | * having d_mountpoint() true, so there's no need to call back |
10584211 IK |
383 | * to the daemon. |
384 | */ | |
385 | if (dentry->d_inode && S_ISLNK(dentry->d_inode->i_mode)) | |
386 | goto done; | |
b5b80177 IK |
387 | if (!d_mountpoint(dentry)) { |
388 | /* | |
389 | * It's possible that user space hasn't removed directories | |
390 | * after umounting a rootless multi-mount, although it | |
391 | * should. For v5 have_submounts() is sufficient to handle | |
392 | * this because the leaves of the directory tree under the | |
393 | * mount never trigger mounts themselves (they have an autofs | |
394 | * trigger mount mounted on them). But v4 pseudo direct mounts | |
395 | * do need the leaves to to trigger mounts. In this case we | |
396 | * have no choice but to use the list_empty() check and | |
397 | * require user space behave. | |
398 | */ | |
399 | if (sbi->version > 4) { | |
400 | if (have_submounts(dentry)) | |
401 | goto done; | |
402 | } else { | |
403 | spin_lock(&dentry->d_lock); | |
404 | if (!list_empty(&dentry->d_subdirs)) { | |
405 | spin_unlock(&dentry->d_lock); | |
406 | goto done; | |
407 | } | |
408 | spin_unlock(&dentry->d_lock); | |
409 | } | |
10584211 | 410 | ino->flags |= AUTOFS_INF_PENDING; |
10584211 IK |
411 | spin_unlock(&sbi->fs_lock); |
412 | status = autofs4_mount_wait(dentry); | |
413 | if (status) | |
414 | return ERR_PTR(status); | |
415 | spin_lock(&sbi->fs_lock); | |
416 | ino->flags &= ~AUTOFS_INF_PENDING; | |
10584211 | 417 | } |
10584211 | 418 | done: |
b5b80177 IK |
419 | if (!(ino->flags & AUTOFS_INF_EXPIRING)) { |
420 | /* | |
421 | * Any needed mounting has been completed and the path updated | |
422 | * so turn this into a normal dentry so we don't continually | |
423 | * call ->d_automount() and ->d_manage(). | |
424 | */ | |
425 | spin_lock(&dentry->d_lock); | |
426 | __managed_dentry_clear_transit(dentry); | |
427 | /* | |
428 | * Only clear DMANAGED_AUTOMOUNT for rootless multi-mounts and | |
429 | * symlinks as in all other cases the dentry will be covered by | |
430 | * an actual mount so ->d_automount() won't be called during | |
431 | * the follow. | |
432 | */ | |
433 | if ((!d_mountpoint(dentry) && | |
434 | !list_empty(&dentry->d_subdirs)) || | |
435 | (dentry->d_inode && S_ISLNK(dentry->d_inode->i_mode))) | |
436 | __managed_dentry_clear_automount(dentry); | |
437 | spin_unlock(&dentry->d_lock); | |
438 | } | |
10584211 IK |
439 | spin_unlock(&sbi->fs_lock); |
440 | ||
441 | /* Mount succeeded, check if we ended up with a new dentry */ | |
442 | dentry = autofs4_mountpoint_changed(path); | |
443 | if (!dentry) | |
444 | return ERR_PTR(-ENOENT); | |
445 | ||
446 | return NULL; | |
447 | } | |
448 | ||
ab90911f | 449 | int autofs4_d_manage(struct dentry *dentry, bool mounting_here, bool rcu_walk) |
b5b80177 IK |
450 | { |
451 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); | |
452 | ||
453 | DPRINTK("dentry=%p %.*s", | |
454 | dentry, dentry->d_name.len, dentry->d_name.name); | |
455 | ||
456 | /* The daemon never waits. */ | |
457 | if (autofs4_oz_mode(sbi) || mounting_here) { | |
458 | if (!d_mountpoint(dentry)) | |
459 | return -EISDIR; | |
460 | return 0; | |
461 | } | |
462 | ||
ab90911f DH |
463 | /* We need to sleep, so we need pathwalk to be in ref-mode */ |
464 | if (rcu_walk) | |
465 | return -ECHILD; | |
466 | ||
b5b80177 IK |
467 | /* Wait for pending expires */ |
468 | do_expire_wait(dentry); | |
469 | ||
470 | /* | |
471 | * This dentry may be under construction so wait on mount | |
472 | * completion. | |
473 | */ | |
474 | return autofs4_mount_wait(dentry); | |
475 | } | |
476 | ||
1da177e4 LT |
477 | /* Lookups in the root directory */ |
478 | static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) | |
479 | { | |
480 | struct autofs_sb_info *sbi; | |
25767378 | 481 | struct autofs_info *ino; |
10584211 | 482 | struct dentry *active; |
1da177e4 | 483 | |
10584211 | 484 | DPRINTK("name = %.*s", dentry->d_name.len, dentry->d_name.name); |
1da177e4 | 485 | |
718c604a | 486 | /* File name too long to exist */ |
1da177e4 | 487 | if (dentry->d_name.len > NAME_MAX) |
718c604a | 488 | return ERR_PTR(-ENAMETOOLONG); |
1da177e4 LT |
489 | |
490 | sbi = autofs4_sbi(dir->i_sb); | |
718c604a | 491 | |
1da177e4 | 492 | DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d", |
c0bcc9d5 IK |
493 | current->pid, task_pgrp_nr(current), sbi->catatonic, |
494 | autofs4_oz_mode(sbi)); | |
1da177e4 | 495 | |
6510c9d8 | 496 | active = autofs4_lookup_active(dentry); |
90387c9c | 497 | if (active) { |
10584211 | 498 | return active; |
aa952eb2 | 499 | } else { |
4b1ae27a | 500 | /* |
10584211 IK |
501 | * A dentry that is not within the root can never trigger a |
502 | * mount operation, unless the directory already exists, so we | |
503 | * can return fail immediately. The daemon however does need | |
504 | * to create directories within the file system. | |
4b1ae27a | 505 | */ |
10584211 IK |
506 | if (!autofs4_oz_mode(sbi) && !IS_ROOT(dentry->d_parent)) |
507 | return ERR_PTR(-ENOENT); | |
508 | ||
509 | /* Mark entries in the root as mount triggers */ | |
b650c858 | 510 | if (autofs_type_indirect(sbi->type) && IS_ROOT(dentry->d_parent)) |
b5b80177 | 511 | __managed_dentry_set_managed(dentry); |
10584211 | 512 | |
26e6c910 | 513 | ino = autofs4_new_ino(sbi); |
4b1ae27a AV |
514 | if (!ino) |
515 | return ERR_PTR(-ENOMEM); | |
516 | ||
517 | dentry->d_fsdata = ino; | |
518 | ino->dentry = dentry; | |
5f6f4f28 | 519 | |
4b1ae27a AV |
520 | autofs4_add_active(dentry); |
521 | ||
522 | d_instantiate(dentry, NULL); | |
523 | } | |
1da177e4 LT |
524 | return NULL; |
525 | } | |
526 | ||
527 | static int autofs4_dir_symlink(struct inode *dir, | |
528 | struct dentry *dentry, | |
529 | const char *symname) | |
530 | { | |
531 | struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); | |
532 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
1aff3c8b | 533 | struct autofs_info *p_ino; |
1da177e4 | 534 | struct inode *inode; |
0bf71d4d | 535 | size_t size = strlen(symname); |
1da177e4 LT |
536 | char *cp; |
537 | ||
538 | DPRINTK("%s <- %.*s", symname, | |
539 | dentry->d_name.len, dentry->d_name.name); | |
540 | ||
541 | if (!autofs4_oz_mode(sbi)) | |
542 | return -EACCES; | |
543 | ||
5a37db30 AV |
544 | BUG_ON(!ino); |
545 | ||
26e6c910 | 546 | autofs4_clean_ino(ino); |
1da177e4 | 547 | |
4b1ae27a AV |
548 | autofs4_del_active(dentry); |
549 | ||
0bf71d4d | 550 | cp = kmalloc(size + 1, GFP_KERNEL); |
5a37db30 | 551 | if (!cp) |
25767378 | 552 | return -ENOMEM; |
1da177e4 LT |
553 | |
554 | strcpy(cp, symname); | |
555 | ||
726a5e06 | 556 | inode = autofs4_get_inode(dir->i_sb, S_IFLNK | 0555); |
25767378 IK |
557 | if (!inode) { |
558 | kfree(cp); | |
559 | if (!dentry->d_fsdata) | |
560 | kfree(ino); | |
561 | return -ENOMEM; | |
562 | } | |
292c5ee8 | 563 | inode->i_private = cp; |
0bf71d4d | 564 | inode->i_size = size; |
1864f7bd | 565 | d_add(dentry, inode); |
1da177e4 | 566 | |
5a37db30 | 567 | dget(dentry); |
1aff3c8b IK |
568 | atomic_inc(&ino->count); |
569 | p_ino = autofs4_dentry_ino(dentry->d_parent); | |
570 | if (p_ino && dentry->d_parent != dentry) | |
571 | atomic_inc(&p_ino->count); | |
1da177e4 LT |
572 | |
573 | dir->i_mtime = CURRENT_TIME; | |
574 | ||
575 | return 0; | |
576 | } | |
577 | ||
578 | /* | |
579 | * NOTE! | |
580 | * | |
581 | * Normal filesystems would do a "d_delete()" to tell the VFS dcache | |
582 | * that the file no longer exists. However, doing that means that the | |
583 | * VFS layer can turn the dentry into a negative dentry. We don't want | |
f50b6f86 | 584 | * this, because the unlink is probably the result of an expire. |
5f6f4f28 IK |
585 | * We simply d_drop it and add it to a expiring list in the super block, |
586 | * which allows the dentry lookup to check for an incomplete expire. | |
1da177e4 LT |
587 | * |
588 | * If a process is blocked on the dentry waiting for the expire to finish, | |
589 | * it will invalidate the dentry and try to mount with a new one. | |
590 | * | |
591 | * Also see autofs4_dir_rmdir().. | |
592 | */ | |
593 | static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry) | |
594 | { | |
595 | struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); | |
596 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
1aff3c8b | 597 | struct autofs_info *p_ino; |
1da177e4 LT |
598 | |
599 | /* This allows root to remove symlinks */ | |
d78e53c8 | 600 | if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN)) |
1da177e4 LT |
601 | return -EACCES; |
602 | ||
1aff3c8b IK |
603 | if (atomic_dec_and_test(&ino->count)) { |
604 | p_ino = autofs4_dentry_ino(dentry->d_parent); | |
605 | if (p_ino && dentry->d_parent != dentry) | |
606 | atomic_dec(&p_ino->count); | |
607 | } | |
1da177e4 LT |
608 | dput(ino->dentry); |
609 | ||
610 | dentry->d_inode->i_size = 0; | |
ce71ec36 | 611 | clear_nlink(dentry->d_inode); |
1da177e4 LT |
612 | |
613 | dir->i_mtime = CURRENT_TIME; | |
614 | ||
b5c84bf6 | 615 | spin_lock(&autofs4_lock); |
4b1ae27a | 616 | autofs4_add_expiring(dentry); |
f50b6f86 IK |
617 | spin_lock(&dentry->d_lock); |
618 | __d_drop(dentry); | |
619 | spin_unlock(&dentry->d_lock); | |
b5c84bf6 | 620 | spin_unlock(&autofs4_lock); |
1da177e4 LT |
621 | |
622 | return 0; | |
623 | } | |
624 | ||
dd89f90d IK |
625 | /* |
626 | * Version 4 of autofs provides a pseudo direct mount implementation | |
627 | * that relies on directories at the leaves of a directory tree under | |
628 | * an indirect mount to trigger mounts. To allow for this we need to | |
629 | * set the DMANAGED_AUTOMOUNT and DMANAGED_TRANSIT flags on the leaves | |
630 | * of the directory tree. There is no need to clear the automount flag | |
631 | * following a mount or restore it after an expire because these mounts | |
632 | * are always covered. However, it is neccessary to ensure that these | |
633 | * flags are clear on non-empty directories to avoid unnecessary calls | |
634 | * during path walks. | |
635 | */ | |
636 | static void autofs_set_leaf_automount_flags(struct dentry *dentry) | |
637 | { | |
638 | struct dentry *parent; | |
639 | ||
640 | /* root and dentrys in the root are already handled */ | |
641 | if (IS_ROOT(dentry->d_parent)) | |
642 | return; | |
643 | ||
644 | managed_dentry_set_managed(dentry); | |
645 | ||
646 | parent = dentry->d_parent; | |
647 | /* only consider parents below dentrys in the root */ | |
648 | if (IS_ROOT(parent->d_parent)) | |
649 | return; | |
650 | managed_dentry_clear_managed(parent); | |
651 | return; | |
652 | } | |
653 | ||
654 | static void autofs_clear_leaf_automount_flags(struct dentry *dentry) | |
655 | { | |
656 | struct list_head *d_child; | |
657 | struct dentry *parent; | |
658 | ||
659 | /* flags for dentrys in the root are handled elsewhere */ | |
660 | if (IS_ROOT(dentry->d_parent)) | |
661 | return; | |
662 | ||
663 | managed_dentry_clear_managed(dentry); | |
664 | ||
665 | parent = dentry->d_parent; | |
666 | /* only consider parents below dentrys in the root */ | |
667 | if (IS_ROOT(parent->d_parent)) | |
668 | return; | |
669 | d_child = &dentry->d_u.d_child; | |
670 | /* Set parent managed if it's becoming empty */ | |
671 | if (d_child->next == &parent->d_subdirs && | |
672 | d_child->prev == &parent->d_subdirs) | |
673 | managed_dentry_set_managed(parent); | |
674 | return; | |
675 | } | |
676 | ||
1da177e4 LT |
677 | static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry) |
678 | { | |
679 | struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); | |
680 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
1aff3c8b | 681 | struct autofs_info *p_ino; |
1da177e4 | 682 | |
f50b6f86 IK |
683 | DPRINTK("dentry %p, removing %.*s", |
684 | dentry, dentry->d_name.len, dentry->d_name.name); | |
685 | ||
1da177e4 LT |
686 | if (!autofs4_oz_mode(sbi)) |
687 | return -EACCES; | |
688 | ||
b5c84bf6 | 689 | spin_lock(&autofs4_lock); |
2fd6b7f5 NP |
690 | spin_lock(&sbi->lookup_lock); |
691 | spin_lock(&dentry->d_lock); | |
1da177e4 | 692 | if (!list_empty(&dentry->d_subdirs)) { |
2fd6b7f5 NP |
693 | spin_unlock(&dentry->d_lock); |
694 | spin_unlock(&sbi->lookup_lock); | |
b5c84bf6 | 695 | spin_unlock(&autofs4_lock); |
1da177e4 LT |
696 | return -ENOTEMPTY; |
697 | } | |
2fd6b7f5 NP |
698 | __autofs4_add_expiring(dentry); |
699 | spin_unlock(&sbi->lookup_lock); | |
1da177e4 LT |
700 | __d_drop(dentry); |
701 | spin_unlock(&dentry->d_lock); | |
b5c84bf6 | 702 | spin_unlock(&autofs4_lock); |
1da177e4 | 703 | |
dd89f90d IK |
704 | if (sbi->version < 5) |
705 | autofs_clear_leaf_automount_flags(dentry); | |
706 | ||
1aff3c8b IK |
707 | if (atomic_dec_and_test(&ino->count)) { |
708 | p_ino = autofs4_dentry_ino(dentry->d_parent); | |
709 | if (p_ino && dentry->d_parent != dentry) | |
710 | atomic_dec(&p_ino->count); | |
711 | } | |
1da177e4 | 712 | dput(ino->dentry); |
1da177e4 | 713 | dentry->d_inode->i_size = 0; |
ce71ec36 | 714 | clear_nlink(dentry->d_inode); |
1da177e4 LT |
715 | |
716 | if (dir->i_nlink) | |
9a53c3a7 | 717 | drop_nlink(dir); |
1da177e4 LT |
718 | |
719 | return 0; | |
720 | } | |
721 | ||
722 | static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
723 | { | |
724 | struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); | |
725 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
1aff3c8b | 726 | struct autofs_info *p_ino; |
1da177e4 LT |
727 | struct inode *inode; |
728 | ||
d78e53c8 | 729 | if (!autofs4_oz_mode(sbi)) |
1da177e4 LT |
730 | return -EACCES; |
731 | ||
732 | DPRINTK("dentry %p, creating %.*s", | |
733 | dentry, dentry->d_name.len, dentry->d_name.name); | |
734 | ||
5a37db30 AV |
735 | BUG_ON(!ino); |
736 | ||
26e6c910 | 737 | autofs4_clean_ino(ino); |
25767378 | 738 | |
4b1ae27a AV |
739 | autofs4_del_active(dentry); |
740 | ||
726a5e06 | 741 | inode = autofs4_get_inode(dir->i_sb, S_IFDIR | 0555); |
5a37db30 | 742 | if (!inode) |
25767378 | 743 | return -ENOMEM; |
1864f7bd | 744 | d_add(dentry, inode); |
1da177e4 | 745 | |
dd89f90d IK |
746 | if (sbi->version < 5) |
747 | autofs_set_leaf_automount_flags(dentry); | |
748 | ||
5a37db30 | 749 | dget(dentry); |
1aff3c8b IK |
750 | atomic_inc(&ino->count); |
751 | p_ino = autofs4_dentry_ino(dentry->d_parent); | |
752 | if (p_ino && dentry->d_parent != dentry) | |
753 | atomic_inc(&p_ino->count); | |
d8c76e6f | 754 | inc_nlink(dir); |
1da177e4 LT |
755 | dir->i_mtime = CURRENT_TIME; |
756 | ||
757 | return 0; | |
758 | } | |
759 | ||
760 | /* Get/set timeout ioctl() operation */ | |
c9243f5b AB |
761 | #ifdef CONFIG_COMPAT |
762 | static inline int autofs4_compat_get_set_timeout(struct autofs_sb_info *sbi, | |
763 | compat_ulong_t __user *p) | |
764 | { | |
765 | int rv; | |
766 | unsigned long ntimeout; | |
767 | ||
768 | if ((rv = get_user(ntimeout, p)) || | |
769 | (rv = put_user(sbi->exp_timeout/HZ, p))) | |
770 | return rv; | |
771 | ||
772 | if (ntimeout > UINT_MAX/HZ) | |
773 | sbi->exp_timeout = 0; | |
774 | else | |
775 | sbi->exp_timeout = ntimeout * HZ; | |
776 | ||
777 | return 0; | |
778 | } | |
779 | #endif | |
780 | ||
1da177e4 LT |
781 | static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi, |
782 | unsigned long __user *p) | |
783 | { | |
784 | int rv; | |
785 | unsigned long ntimeout; | |
786 | ||
d78e53c8 SB |
787 | if ((rv = get_user(ntimeout, p)) || |
788 | (rv = put_user(sbi->exp_timeout/HZ, p))) | |
1da177e4 LT |
789 | return rv; |
790 | ||
d78e53c8 | 791 | if (ntimeout > ULONG_MAX/HZ) |
1da177e4 LT |
792 | sbi->exp_timeout = 0; |
793 | else | |
794 | sbi->exp_timeout = ntimeout * HZ; | |
795 | ||
796 | return 0; | |
797 | } | |
798 | ||
799 | /* Return protocol version */ | |
800 | static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int __user *p) | |
801 | { | |
802 | return put_user(sbi->version, p); | |
803 | } | |
804 | ||
805 | /* Return protocol sub version */ | |
806 | static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p) | |
807 | { | |
808 | return put_user(sbi->sub_version, p); | |
809 | } | |
810 | ||
1da177e4 LT |
811 | /* |
812 | * Tells the daemon whether it can umount the autofs mount. | |
813 | */ | |
814 | static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p) | |
815 | { | |
816 | int status = 0; | |
817 | ||
e3474a8e | 818 | if (may_umount(mnt)) |
1da177e4 LT |
819 | status = 1; |
820 | ||
821 | DPRINTK("returning %d", status); | |
822 | ||
823 | status = put_user(status, p); | |
824 | ||
825 | return status; | |
826 | } | |
827 | ||
828 | /* Identify autofs4_dentries - this is so we can tell if there's | |
829 | an extra dentry refcount or not. We only hold a refcount on the | |
830 | dentry if its non-negative (ie, d_inode != NULL) | |
831 | */ | |
832 | int is_autofs4_dentry(struct dentry *dentry) | |
833 | { | |
834 | return dentry && dentry->d_inode && | |
b650c858 | 835 | dentry->d_op == &autofs4_dentry_operations && |
1da177e4 LT |
836 | dentry->d_fsdata != NULL; |
837 | } | |
838 | ||
839 | /* | |
840 | * ioctl()'s on the root directory is the chief method for the daemon to | |
841 | * generate kernel reactions | |
842 | */ | |
3663df70 FW |
843 | static int autofs4_root_ioctl_unlocked(struct inode *inode, struct file *filp, |
844 | unsigned int cmd, unsigned long arg) | |
1da177e4 LT |
845 | { |
846 | struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb); | |
847 | void __user *p = (void __user *)arg; | |
848 | ||
849 | DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u", | |
a47afb0f | 850 | cmd,arg,sbi,task_pgrp_nr(current)); |
1da177e4 | 851 | |
d78e53c8 SB |
852 | if (_IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) || |
853 | _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT) | |
1da177e4 LT |
854 | return -ENOTTY; |
855 | ||
d78e53c8 | 856 | if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN)) |
1da177e4 LT |
857 | return -EPERM; |
858 | ||
859 | switch(cmd) { | |
860 | case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */ | |
861 | return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0); | |
862 | case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */ | |
863 | return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT); | |
864 | case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */ | |
865 | autofs4_catatonic_mode(sbi); | |
866 | return 0; | |
867 | case AUTOFS_IOC_PROTOVER: /* Get protocol version */ | |
868 | return autofs4_get_protover(sbi, p); | |
869 | case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */ | |
870 | return autofs4_get_protosubver(sbi, p); | |
871 | case AUTOFS_IOC_SETTIMEOUT: | |
872 | return autofs4_get_set_timeout(sbi, p); | |
c9243f5b AB |
873 | #ifdef CONFIG_COMPAT |
874 | case AUTOFS_IOC_SETTIMEOUT32: | |
875 | return autofs4_compat_get_set_timeout(sbi, p); | |
876 | #endif | |
1da177e4 | 877 | |
1da177e4 | 878 | case AUTOFS_IOC_ASKUMOUNT: |
a4669ed8 | 879 | return autofs4_ask_umount(filp->f_path.mnt, p); |
1da177e4 LT |
880 | |
881 | /* return a single thing to expire */ | |
882 | case AUTOFS_IOC_EXPIRE: | |
a4669ed8 | 883 | return autofs4_expire_run(inode->i_sb,filp->f_path.mnt,sbi, p); |
1da177e4 LT |
884 | /* same as above, but can send multiple expires through pipe */ |
885 | case AUTOFS_IOC_EXPIRE_MULTI: | |
a4669ed8 | 886 | return autofs4_expire_multi(inode->i_sb,filp->f_path.mnt,sbi, p); |
1da177e4 LT |
887 | |
888 | default: | |
889 | return -ENOSYS; | |
890 | } | |
891 | } | |
3663df70 FW |
892 | |
893 | static long autofs4_root_ioctl(struct file *filp, | |
894 | unsigned int cmd, unsigned long arg) | |
895 | { | |
3663df70 | 896 | struct inode *inode = filp->f_dentry->d_inode; |
de47de74 | 897 | return autofs4_root_ioctl_unlocked(inode, filp, cmd, arg); |
3663df70 | 898 | } |
c9243f5b AB |
899 | |
900 | #ifdef CONFIG_COMPAT | |
901 | static long autofs4_root_compat_ioctl(struct file *filp, | |
902 | unsigned int cmd, unsigned long arg) | |
903 | { | |
904 | struct inode *inode = filp->f_path.dentry->d_inode; | |
905 | int ret; | |
906 | ||
c9243f5b AB |
907 | if (cmd == AUTOFS_IOC_READY || cmd == AUTOFS_IOC_FAIL) |
908 | ret = autofs4_root_ioctl_unlocked(inode, filp, cmd, arg); | |
909 | else | |
910 | ret = autofs4_root_ioctl_unlocked(inode, filp, cmd, | |
911 | (unsigned long)compat_ptr(arg)); | |
c9243f5b AB |
912 | |
913 | return ret; | |
914 | } | |
915 | #endif |