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> | |
18 | #include <linux/param.h> | |
19 | #include <linux/time.h> | |
1da177e4 LT |
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); | |
1da177e4 | 28 | static struct dentry *autofs4_lookup(struct inode *,struct dentry *, struct nameidata *); |
34ca959c | 29 | static void *autofs4_follow_link(struct dentry *, struct nameidata *); |
1da177e4 | 30 | |
6d5cb926 IK |
31 | #define TRIGGER_FLAGS (LOOKUP_CONTINUE | LOOKUP_DIRECTORY) |
32 | #define TRIGGER_INTENTS (LOOKUP_OPEN | LOOKUP_CREATE) | |
33 | ||
4b6f5d20 | 34 | const struct file_operations autofs4_root_operations = { |
1da177e4 LT |
35 | .open = dcache_dir_open, |
36 | .release = dcache_dir_close, | |
37 | .read = generic_read_dir, | |
aa55ddf3 | 38 | .readdir = dcache_readdir, |
59af1584 | 39 | .llseek = dcache_dir_lseek, |
1da177e4 LT |
40 | .ioctl = autofs4_root_ioctl, |
41 | }; | |
42 | ||
4b6f5d20 | 43 | const struct file_operations autofs4_dir_operations = { |
1da177e4 | 44 | .open = autofs4_dir_open, |
ff9cd499 | 45 | .release = dcache_dir_close, |
1da177e4 | 46 | .read = generic_read_dir, |
ff9cd499 | 47 | .readdir = dcache_readdir, |
59af1584 | 48 | .llseek = dcache_dir_lseek, |
1da177e4 LT |
49 | }; |
50 | ||
754661f1 | 51 | const struct inode_operations autofs4_indirect_root_inode_operations = { |
1da177e4 LT |
52 | .lookup = autofs4_lookup, |
53 | .unlink = autofs4_dir_unlink, | |
54 | .symlink = autofs4_dir_symlink, | |
55 | .mkdir = autofs4_dir_mkdir, | |
56 | .rmdir = autofs4_dir_rmdir, | |
57 | }; | |
58 | ||
754661f1 | 59 | const struct inode_operations autofs4_direct_root_inode_operations = { |
34ca959c | 60 | .lookup = autofs4_lookup, |
871f9434 IK |
61 | .unlink = autofs4_dir_unlink, |
62 | .mkdir = autofs4_dir_mkdir, | |
63 | .rmdir = autofs4_dir_rmdir, | |
34ca959c IK |
64 | .follow_link = autofs4_follow_link, |
65 | }; | |
66 | ||
754661f1 | 67 | const struct inode_operations autofs4_dir_inode_operations = { |
1da177e4 LT |
68 | .lookup = autofs4_lookup, |
69 | .unlink = autofs4_dir_unlink, | |
70 | .symlink = autofs4_dir_symlink, | |
71 | .mkdir = autofs4_dir_mkdir, | |
72 | .rmdir = autofs4_dir_rmdir, | |
73 | }; | |
74 | ||
1da177e4 LT |
75 | static int autofs4_dir_open(struct inode *inode, struct file *file) |
76 | { | |
a4669ed8 | 77 | struct dentry *dentry = file->f_path.dentry; |
1da177e4 | 78 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); |
f360ce3b | 79 | |
1da177e4 LT |
80 | DPRINTK("file=%p dentry=%p %.*s", |
81 | file, dentry, dentry->d_name.len, dentry->d_name.name); | |
82 | ||
83 | if (autofs4_oz_mode(sbi)) | |
84 | goto out; | |
85 | ||
ff9cd499 IK |
86 | /* |
87 | * An empty directory in an autofs file system is always a | |
88 | * mount point. The daemon must have failed to mount this | |
89 | * during lookup so it doesn't exist. This can happen, for | |
90 | * example, if user space returns an incorrect status for a | |
91 | * mount request. Otherwise we're doing a readdir on the | |
92 | * autofs file system so just let the libfs routines handle | |
93 | * it. | |
94 | */ | |
95 | spin_lock(&dcache_lock); | |
96 | if (!d_mountpoint(dentry) && __simple_empty(dentry)) { | |
1da177e4 | 97 | spin_unlock(&dcache_lock); |
ff9cd499 | 98 | return -ENOENT; |
1da177e4 | 99 | } |
ff9cd499 | 100 | spin_unlock(&dcache_lock); |
1da177e4 | 101 | |
1da177e4 | 102 | out: |
ff9cd499 | 103 | return dcache_dir_open(inode, file); |
1da177e4 LT |
104 | } |
105 | ||
862b110f | 106 | static int try_to_fill_dentry(struct dentry *dentry, int flags) |
1da177e4 | 107 | { |
862b110f | 108 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); |
718c604a | 109 | struct autofs_info *ino = autofs4_dentry_ino(dentry); |
9d2de6ad | 110 | int status; |
1da177e4 | 111 | |
1da177e4 LT |
112 | DPRINTK("dentry=%p %.*s ino=%p", |
113 | dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_inode); | |
114 | ||
718c604a IK |
115 | /* |
116 | * Wait for a pending mount, triggering one if there | |
117 | * isn't one already | |
118 | */ | |
1da177e4 LT |
119 | if (dentry->d_inode == NULL) { |
120 | DPRINTK("waiting for mount name=%.*s", | |
121 | dentry->d_name.len, dentry->d_name.name); | |
122 | ||
123 | status = autofs4_wait(sbi, dentry, NFY_MOUNT); | |
718c604a | 124 | |
1da177e4 LT |
125 | DPRINTK("mount done status=%d", status); |
126 | ||
1da177e4 LT |
127 | /* Turn this into a real negative dentry? */ |
128 | if (status == -ENOENT) { | |
1da177e4 LT |
129 | spin_lock(&dentry->d_lock); |
130 | dentry->d_flags &= ~DCACHE_AUTOFS_PENDING; | |
131 | spin_unlock(&dentry->d_lock); | |
34ca959c | 132 | return status; |
1da177e4 LT |
133 | } else if (status) { |
134 | /* Return a negative dentry, but leave it "pending" */ | |
34ca959c | 135 | return status; |
1da177e4 LT |
136 | } |
137 | /* Trigger mount for path component or follow link */ | |
26e81b31 IK |
138 | } else if (dentry->d_flags & DCACHE_AUTOFS_PENDING || |
139 | flags & (TRIGGER_FLAGS | TRIGGER_INTENTS) || | |
1da177e4 LT |
140 | current->link_count) { |
141 | DPRINTK("waiting for mount name=%.*s", | |
142 | dentry->d_name.len, dentry->d_name.name); | |
143 | ||
144 | spin_lock(&dentry->d_lock); | |
145 | dentry->d_flags |= DCACHE_AUTOFS_PENDING; | |
146 | spin_unlock(&dentry->d_lock); | |
147 | status = autofs4_wait(sbi, dentry, NFY_MOUNT); | |
148 | ||
149 | DPRINTK("mount done status=%d", status); | |
150 | ||
151 | if (status) { | |
152 | spin_lock(&dentry->d_lock); | |
153 | dentry->d_flags &= ~DCACHE_AUTOFS_PENDING; | |
154 | spin_unlock(&dentry->d_lock); | |
34ca959c | 155 | return status; |
1da177e4 LT |
156 | } |
157 | } | |
158 | ||
e0a7aae9 IK |
159 | /* Initialize expiry counter after successful mount */ |
160 | if (ino) | |
161 | ino->last_used = jiffies; | |
162 | ||
1da177e4 LT |
163 | spin_lock(&dentry->d_lock); |
164 | dentry->d_flags &= ~DCACHE_AUTOFS_PENDING; | |
165 | spin_unlock(&dentry->d_lock); | |
03379044 | 166 | |
9d2de6ad | 167 | return 0; |
34ca959c IK |
168 | } |
169 | ||
170 | /* For autofs direct mounts the follow link triggers the mount */ | |
171 | static void *autofs4_follow_link(struct dentry *dentry, struct nameidata *nd) | |
172 | { | |
173 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); | |
a5370553 | 174 | struct autofs_info *ino = autofs4_dentry_ino(dentry); |
34ca959c IK |
175 | int oz_mode = autofs4_oz_mode(sbi); |
176 | unsigned int lookup_type; | |
177 | int status; | |
178 | ||
179 | DPRINTK("dentry=%p %.*s oz_mode=%d nd->flags=%d", | |
180 | dentry, dentry->d_name.len, dentry->d_name.name, oz_mode, | |
181 | nd->flags); | |
6e60a9ab IK |
182 | /* |
183 | * For an expire of a covered direct or offset mount we need | |
9393bd07 | 184 | * to break out of follow_down() at the autofs mount trigger |
6e60a9ab IK |
185 | * (d_mounted--), so we can see the expiring flag, and manage |
186 | * the blocking and following here until the expire is completed. | |
187 | */ | |
188 | if (oz_mode) { | |
189 | spin_lock(&sbi->fs_lock); | |
190 | if (ino->flags & AUTOFS_INF_EXPIRING) { | |
191 | spin_unlock(&sbi->fs_lock); | |
192 | /* Follow down to our covering mount. */ | |
9393bd07 | 193 | if (!follow_down(&nd->path)) |
6e60a9ab | 194 | goto done; |
ec6e8c7d | 195 | goto follow; |
6e60a9ab IK |
196 | } |
197 | spin_unlock(&sbi->fs_lock); | |
34ca959c | 198 | goto done; |
6e60a9ab | 199 | } |
34ca959c | 200 | |
6e60a9ab | 201 | /* If an expire request is pending everyone must wait. */ |
06a35985 | 202 | autofs4_expire_wait(dentry); |
871f9434 | 203 | |
6e60a9ab IK |
204 | /* We trigger a mount for almost all flags */ |
205 | lookup_type = nd->flags & (TRIGGER_FLAGS | TRIGGER_INTENTS); | |
206 | if (!(lookup_type || dentry->d_flags & DCACHE_AUTOFS_PENDING)) | |
ec6e8c7d | 207 | goto follow; |
6e60a9ab | 208 | |
871f9434 | 209 | /* |
6e60a9ab IK |
210 | * If the dentry contains directories then it is an autofs |
211 | * multi-mount with no root mount offset. So don't try to | |
212 | * mount it again. | |
871f9434 IK |
213 | */ |
214 | spin_lock(&dcache_lock); | |
26e81b31 IK |
215 | if (dentry->d_flags & DCACHE_AUTOFS_PENDING || |
216 | (!d_mountpoint(dentry) && __simple_empty(dentry))) { | |
871f9434 IK |
217 | spin_unlock(&dcache_lock); |
218 | ||
219 | status = try_to_fill_dentry(dentry, 0); | |
220 | if (status) | |
221 | goto out_error; | |
222 | ||
6e60a9ab | 223 | goto follow; |
34ca959c | 224 | } |
871f9434 | 225 | spin_unlock(&dcache_lock); |
6e60a9ab IK |
226 | follow: |
227 | /* | |
228 | * If there is no root mount it must be an autofs | |
229 | * multi-mount with no root offset so we don't need | |
230 | * to follow it. | |
231 | */ | |
232 | if (d_mountpoint(dentry)) { | |
9393bd07 | 233 | if (!autofs4_follow_mount(&nd->path)) { |
6e60a9ab IK |
234 | status = -ENOENT; |
235 | goto out_error; | |
236 | } | |
237 | } | |
34ca959c IK |
238 | |
239 | done: | |
240 | return NULL; | |
241 | ||
242 | out_error: | |
1d957f9b | 243 | path_put(&nd->path); |
34ca959c | 244 | return ERR_PTR(status); |
1da177e4 LT |
245 | } |
246 | ||
247 | /* | |
248 | * Revalidate is called on every cache lookup. Some of those | |
249 | * cache lookups may actually happen while the dentry is not | |
250 | * yet completely filled in, and revalidate has to delay such | |
251 | * lookups.. | |
252 | */ | |
718c604a | 253 | static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd) |
1da177e4 | 254 | { |
718c604a | 255 | struct inode *dir = dentry->d_parent->d_inode; |
1da177e4 LT |
256 | struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); |
257 | int oz_mode = autofs4_oz_mode(sbi); | |
258 | int flags = nd ? nd->flags : 0; | |
bcdc5e01 | 259 | int status = 1; |
1da177e4 LT |
260 | |
261 | /* Pending dentry */ | |
97e7449a | 262 | spin_lock(&sbi->fs_lock); |
1da177e4 | 263 | if (autofs4_ispending(dentry)) { |
bcdc5e01 | 264 | /* The daemon never causes a mount to trigger */ |
97e7449a IK |
265 | spin_unlock(&sbi->fs_lock); |
266 | ||
bcdc5e01 IK |
267 | if (oz_mode) |
268 | return 1; | |
269 | ||
06a35985 IK |
270 | /* |
271 | * If the directory has gone away due to an expire | |
272 | * we have been called as ->d_revalidate() and so | |
273 | * we need to return false and proceed to ->lookup(). | |
274 | */ | |
275 | if (autofs4_expire_wait(dentry) == -EAGAIN) | |
276 | return 0; | |
277 | ||
bcdc5e01 IK |
278 | /* |
279 | * A zero status is success otherwise we have a | |
280 | * negative error code. | |
281 | */ | |
282 | status = try_to_fill_dentry(dentry, flags); | |
283 | if (status == 0) | |
f50b6f86 IK |
284 | return 1; |
285 | ||
bcdc5e01 | 286 | return status; |
1da177e4 | 287 | } |
97e7449a | 288 | spin_unlock(&sbi->fs_lock); |
1da177e4 LT |
289 | |
290 | /* Negative dentry.. invalidate if "old" */ | |
291 | if (dentry->d_inode == NULL) | |
2d753e62 | 292 | return 0; |
1da177e4 LT |
293 | |
294 | /* Check for a non-mountpoint directory with no contents */ | |
295 | spin_lock(&dcache_lock); | |
296 | if (S_ISDIR(dentry->d_inode->i_mode) && | |
297 | !d_mountpoint(dentry) && | |
90a59c7c | 298 | __simple_empty(dentry)) { |
1da177e4 LT |
299 | DPRINTK("dentry=%p %.*s, emptydir", |
300 | dentry, dentry->d_name.len, dentry->d_name.name); | |
301 | spin_unlock(&dcache_lock); | |
97e7449a | 302 | |
bcdc5e01 IK |
303 | /* The daemon never causes a mount to trigger */ |
304 | if (oz_mode) | |
305 | return 1; | |
306 | ||
307 | /* | |
308 | * A zero status is success otherwise we have a | |
309 | * negative error code. | |
310 | */ | |
311 | status = try_to_fill_dentry(dentry, flags); | |
312 | if (status == 0) | |
313 | return 1; | |
314 | ||
315 | return status; | |
1da177e4 LT |
316 | } |
317 | spin_unlock(&dcache_lock); | |
318 | ||
1da177e4 LT |
319 | return 1; |
320 | } | |
321 | ||
34ca959c | 322 | void autofs4_dentry_release(struct dentry *de) |
1da177e4 LT |
323 | { |
324 | struct autofs_info *inf; | |
325 | ||
326 | DPRINTK("releasing %p", de); | |
327 | ||
328 | inf = autofs4_dentry_ino(de); | |
329 | de->d_fsdata = NULL; | |
330 | ||
331 | if (inf) { | |
f50b6f86 IK |
332 | struct autofs_sb_info *sbi = autofs4_sbi(de->d_sb); |
333 | ||
f50b6f86 | 334 | if (sbi) { |
5f6f4f28 | 335 | spin_lock(&sbi->lookup_lock); |
25767378 IK |
336 | if (!list_empty(&inf->active)) |
337 | list_del(&inf->active); | |
5f6f4f28 IK |
338 | if (!list_empty(&inf->expiring)) |
339 | list_del(&inf->expiring); | |
340 | spin_unlock(&sbi->lookup_lock); | |
f50b6f86 IK |
341 | } |
342 | ||
c3724b12 JM |
343 | inf->dentry = NULL; |
344 | inf->inode = NULL; | |
345 | ||
1da177e4 LT |
346 | autofs4_free_ino(inf); |
347 | } | |
348 | } | |
349 | ||
350 | /* For dentries of directories in the root dir */ | |
08f11513 | 351 | static const struct dentry_operations autofs4_root_dentry_operations = { |
1da177e4 LT |
352 | .d_revalidate = autofs4_revalidate, |
353 | .d_release = autofs4_dentry_release, | |
354 | }; | |
355 | ||
356 | /* For other dentries */ | |
08f11513 | 357 | static const struct dentry_operations autofs4_dentry_operations = { |
1da177e4 LT |
358 | .d_revalidate = autofs4_revalidate, |
359 | .d_release = autofs4_dentry_release, | |
360 | }; | |
361 | ||
25767378 IK |
362 | static struct dentry *autofs4_lookup_active(struct autofs_sb_info *sbi, struct dentry *parent, struct qstr *name) |
363 | { | |
364 | unsigned int len = name->len; | |
365 | unsigned int hash = name->hash; | |
366 | const unsigned char *str = name->name; | |
367 | struct list_head *p, *head; | |
368 | ||
369 | spin_lock(&dcache_lock); | |
370 | spin_lock(&sbi->lookup_lock); | |
371 | head = &sbi->active_list; | |
372 | list_for_each(p, head) { | |
373 | struct autofs_info *ino; | |
374 | struct dentry *dentry; | |
375 | struct qstr *qstr; | |
376 | ||
377 | ino = list_entry(p, struct autofs_info, active); | |
378 | dentry = ino->dentry; | |
379 | ||
380 | spin_lock(&dentry->d_lock); | |
381 | ||
382 | /* Already gone? */ | |
383 | if (atomic_read(&dentry->d_count) == 0) | |
384 | goto next; | |
385 | ||
386 | qstr = &dentry->d_name; | |
387 | ||
388 | if (dentry->d_name.hash != hash) | |
389 | goto next; | |
390 | if (dentry->d_parent != parent) | |
391 | goto next; | |
392 | ||
393 | if (qstr->len != len) | |
394 | goto next; | |
395 | if (memcmp(qstr->name, str, len)) | |
396 | goto next; | |
397 | ||
398 | if (d_unhashed(dentry)) { | |
399 | dget(dentry); | |
400 | spin_unlock(&dentry->d_lock); | |
401 | spin_unlock(&sbi->lookup_lock); | |
402 | spin_unlock(&dcache_lock); | |
403 | return dentry; | |
404 | } | |
405 | next: | |
406 | spin_unlock(&dentry->d_lock); | |
407 | } | |
408 | spin_unlock(&sbi->lookup_lock); | |
409 | spin_unlock(&dcache_lock); | |
410 | ||
411 | return NULL; | |
412 | } | |
413 | ||
5f6f4f28 | 414 | static struct dentry *autofs4_lookup_expiring(struct autofs_sb_info *sbi, struct dentry *parent, struct qstr *name) |
f50b6f86 IK |
415 | { |
416 | unsigned int len = name->len; | |
417 | unsigned int hash = name->hash; | |
418 | const unsigned char *str = name->name; | |
419 | struct list_head *p, *head; | |
420 | ||
421 | spin_lock(&dcache_lock); | |
5f6f4f28 IK |
422 | spin_lock(&sbi->lookup_lock); |
423 | head = &sbi->expiring_list; | |
f50b6f86 IK |
424 | list_for_each(p, head) { |
425 | struct autofs_info *ino; | |
426 | struct dentry *dentry; | |
427 | struct qstr *qstr; | |
428 | ||
5f6f4f28 | 429 | ino = list_entry(p, struct autofs_info, expiring); |
f50b6f86 IK |
430 | dentry = ino->dentry; |
431 | ||
432 | spin_lock(&dentry->d_lock); | |
433 | ||
434 | /* Bad luck, we've already been dentry_iput */ | |
435 | if (!dentry->d_inode) | |
436 | goto next; | |
437 | ||
438 | qstr = &dentry->d_name; | |
439 | ||
440 | if (dentry->d_name.hash != hash) | |
441 | goto next; | |
442 | if (dentry->d_parent != parent) | |
443 | goto next; | |
444 | ||
445 | if (qstr->len != len) | |
446 | goto next; | |
447 | if (memcmp(qstr->name, str, len)) | |
448 | goto next; | |
449 | ||
450 | if (d_unhashed(dentry)) { | |
f50b6f86 | 451 | dget(dentry); |
f50b6f86 | 452 | spin_unlock(&dentry->d_lock); |
5f6f4f28 | 453 | spin_unlock(&sbi->lookup_lock); |
f50b6f86 IK |
454 | spin_unlock(&dcache_lock); |
455 | return dentry; | |
456 | } | |
457 | next: | |
458 | spin_unlock(&dentry->d_lock); | |
459 | } | |
5f6f4f28 | 460 | spin_unlock(&sbi->lookup_lock); |
f50b6f86 IK |
461 | spin_unlock(&dcache_lock); |
462 | ||
463 | return NULL; | |
464 | } | |
465 | ||
1da177e4 LT |
466 | /* Lookups in the root directory */ |
467 | static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) | |
468 | { | |
469 | struct autofs_sb_info *sbi; | |
25767378 IK |
470 | struct autofs_info *ino; |
471 | struct dentry *expiring, *unhashed; | |
1da177e4 LT |
472 | int oz_mode; |
473 | ||
474 | DPRINTK("name = %.*s", | |
475 | dentry->d_name.len, dentry->d_name.name); | |
476 | ||
718c604a | 477 | /* File name too long to exist */ |
1da177e4 | 478 | if (dentry->d_name.len > NAME_MAX) |
718c604a | 479 | return ERR_PTR(-ENAMETOOLONG); |
1da177e4 LT |
480 | |
481 | sbi = autofs4_sbi(dir->i_sb); | |
1da177e4 | 482 | oz_mode = autofs4_oz_mode(sbi); |
718c604a | 483 | |
1da177e4 | 484 | DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d", |
a47afb0f | 485 | current->pid, task_pgrp_nr(current), sbi->catatonic, oz_mode); |
1da177e4 | 486 | |
25767378 IK |
487 | unhashed = autofs4_lookup_active(sbi, dentry->d_parent, &dentry->d_name); |
488 | if (unhashed) | |
489 | dentry = unhashed; | |
490 | else { | |
491 | /* | |
492 | * Mark the dentry incomplete but don't hash it. We do this | |
493 | * to serialize our inode creation operations (symlink and | |
494 | * mkdir) which prevents deadlock during the callback to | |
495 | * the daemon. Subsequent user space lookups for the same | |
496 | * dentry are placed on the wait queue while the daemon | |
497 | * itself is allowed passage unresticted so the create | |
498 | * operation itself can then hash the dentry. Finally, | |
499 | * we check for the hashed dentry and return the newly | |
500 | * hashed dentry. | |
501 | */ | |
502 | dentry->d_op = &autofs4_root_dentry_operations; | |
503 | ||
504 | /* | |
505 | * And we need to ensure that the same dentry is used for | |
506 | * all following lookup calls until it is hashed so that | |
507 | * the dentry flags are persistent throughout the request. | |
508 | */ | |
509 | ino = autofs4_init_ino(NULL, sbi, 0555); | |
510 | if (!ino) | |
511 | return ERR_PTR(-ENOMEM); | |
512 | ||
513 | dentry->d_fsdata = ino; | |
514 | ino->dentry = dentry; | |
515 | ||
516 | spin_lock(&sbi->lookup_lock); | |
517 | list_add(&ino->active, &sbi->active_list); | |
518 | spin_unlock(&sbi->lookup_lock); | |
5f6f4f28 | 519 | |
25767378 IK |
520 | d_instantiate(dentry, NULL); |
521 | } | |
5f6f4f28 | 522 | |
1da177e4 | 523 | if (!oz_mode) { |
8f63aaa8 IK |
524 | mutex_unlock(&dir->i_mutex); |
525 | expiring = autofs4_lookup_expiring(sbi, | |
526 | dentry->d_parent, | |
527 | &dentry->d_name); | |
528 | if (expiring) { | |
529 | /* | |
530 | * If we are racing with expire the request might not | |
531 | * be quite complete but the directory has been removed | |
532 | * so it must have been successful, so just wait for it. | |
533 | */ | |
534 | ino = autofs4_dentry_ino(expiring); | |
535 | autofs4_expire_wait(expiring); | |
536 | spin_lock(&sbi->lookup_lock); | |
537 | if (!list_empty(&ino->expiring)) | |
538 | list_del_init(&ino->expiring); | |
539 | spin_unlock(&sbi->lookup_lock); | |
540 | dput(expiring); | |
541 | } | |
542 | ||
1da177e4 LT |
543 | spin_lock(&dentry->d_lock); |
544 | dentry->d_flags |= DCACHE_AUTOFS_PENDING; | |
545 | spin_unlock(&dentry->d_lock); | |
8f63aaa8 | 546 | if (dentry->d_op && dentry->d_op->d_revalidate) |
c432c258 | 547 | (dentry->d_op->d_revalidate)(dentry, nd); |
8f63aaa8 | 548 | mutex_lock(&dir->i_mutex); |
1da177e4 LT |
549 | } |
550 | ||
551 | /* | |
552 | * If we are still pending, check if we had to handle | |
553 | * a signal. If so we can force a restart.. | |
554 | */ | |
555 | if (dentry->d_flags & DCACHE_AUTOFS_PENDING) { | |
556 | /* See if we were interrupted */ | |
557 | if (signal_pending(current)) { | |
558 | sigset_t *sigset = ¤t->pending.signal; | |
559 | if (sigismember (sigset, SIGKILL) || | |
560 | sigismember (sigset, SIGQUIT) || | |
561 | sigismember (sigset, SIGINT)) { | |
25767378 IK |
562 | if (unhashed) |
563 | dput(unhashed); | |
1da177e4 LT |
564 | return ERR_PTR(-ERESTARTNOINTR); |
565 | } | |
566 | } | |
25767378 IK |
567 | if (!oz_mode) { |
568 | spin_lock(&dentry->d_lock); | |
569 | dentry->d_flags &= ~DCACHE_AUTOFS_PENDING; | |
570 | spin_unlock(&dentry->d_lock); | |
571 | } | |
1da177e4 LT |
572 | } |
573 | ||
574 | /* | |
575 | * If this dentry is unhashed, then we shouldn't honour this | |
c9ffec48 IK |
576 | * lookup. Returning ENOENT here doesn't do the right thing |
577 | * for all system calls, but it should be OK for the operations | |
578 | * we permit from an autofs. | |
1da177e4 | 579 | */ |
1864f7bd | 580 | if (!oz_mode && d_unhashed(dentry)) { |
c9ffec48 IK |
581 | /* |
582 | * A user space application can (and has done in the past) | |
583 | * remove and re-create this directory during the callback. | |
584 | * This can leave us with an unhashed dentry, but a | |
585 | * successful mount! So we need to perform another | |
586 | * cached lookup in case the dentry now exists. | |
587 | */ | |
588 | struct dentry *parent = dentry->d_parent; | |
589 | struct dentry *new = d_lookup(parent, &dentry->d_name); | |
590 | if (new != NULL) | |
591 | dentry = new; | |
592 | else | |
593 | dentry = ERR_PTR(-ENOENT); | |
594 | ||
25767378 IK |
595 | if (unhashed) |
596 | dput(unhashed); | |
597 | ||
c9ffec48 | 598 | return dentry; |
f50b6f86 IK |
599 | } |
600 | ||
25767378 IK |
601 | if (unhashed) |
602 | return unhashed; | |
603 | ||
1da177e4 LT |
604 | return NULL; |
605 | } | |
606 | ||
607 | static int autofs4_dir_symlink(struct inode *dir, | |
608 | struct dentry *dentry, | |
609 | const char *symname) | |
610 | { | |
611 | struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); | |
612 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
1aff3c8b | 613 | struct autofs_info *p_ino; |
1da177e4 LT |
614 | struct inode *inode; |
615 | char *cp; | |
616 | ||
617 | DPRINTK("%s <- %.*s", symname, | |
618 | dentry->d_name.len, dentry->d_name.name); | |
619 | ||
620 | if (!autofs4_oz_mode(sbi)) | |
621 | return -EACCES; | |
622 | ||
623 | ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555); | |
25767378 IK |
624 | if (!ino) |
625 | return -ENOMEM; | |
1da177e4 | 626 | |
25767378 IK |
627 | spin_lock(&sbi->lookup_lock); |
628 | if (!list_empty(&ino->active)) | |
629 | list_del_init(&ino->active); | |
630 | spin_unlock(&sbi->lookup_lock); | |
1da177e4 | 631 | |
ef581a74 | 632 | ino->size = strlen(symname); |
25767378 IK |
633 | cp = kmalloc(ino->size + 1, GFP_KERNEL); |
634 | if (!cp) { | |
635 | if (!dentry->d_fsdata) | |
636 | kfree(ino); | |
637 | return -ENOMEM; | |
1da177e4 LT |
638 | } |
639 | ||
640 | strcpy(cp, symname); | |
641 | ||
642 | inode = autofs4_get_inode(dir->i_sb, ino); | |
25767378 IK |
643 | if (!inode) { |
644 | kfree(cp); | |
645 | if (!dentry->d_fsdata) | |
646 | kfree(ino); | |
647 | return -ENOMEM; | |
648 | } | |
1864f7bd | 649 | d_add(dentry, inode); |
1da177e4 LT |
650 | |
651 | if (dir == dir->i_sb->s_root->d_inode) | |
652 | dentry->d_op = &autofs4_root_dentry_operations; | |
653 | else | |
654 | dentry->d_op = &autofs4_dentry_operations; | |
655 | ||
656 | dentry->d_fsdata = ino; | |
657 | ino->dentry = dget(dentry); | |
1aff3c8b IK |
658 | atomic_inc(&ino->count); |
659 | p_ino = autofs4_dentry_ino(dentry->d_parent); | |
660 | if (p_ino && dentry->d_parent != dentry) | |
661 | atomic_inc(&p_ino->count); | |
1da177e4 LT |
662 | ino->inode = inode; |
663 | ||
25767378 | 664 | ino->u.symlink = cp; |
1da177e4 LT |
665 | dir->i_mtime = CURRENT_TIME; |
666 | ||
667 | return 0; | |
668 | } | |
669 | ||
670 | /* | |
671 | * NOTE! | |
672 | * | |
673 | * Normal filesystems would do a "d_delete()" to tell the VFS dcache | |
674 | * that the file no longer exists. However, doing that means that the | |
675 | * VFS layer can turn the dentry into a negative dentry. We don't want | |
f50b6f86 | 676 | * this, because the unlink is probably the result of an expire. |
5f6f4f28 IK |
677 | * We simply d_drop it and add it to a expiring list in the super block, |
678 | * which allows the dentry lookup to check for an incomplete expire. | |
1da177e4 LT |
679 | * |
680 | * If a process is blocked on the dentry waiting for the expire to finish, | |
681 | * it will invalidate the dentry and try to mount with a new one. | |
682 | * | |
683 | * Also see autofs4_dir_rmdir().. | |
684 | */ | |
685 | static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry) | |
686 | { | |
687 | struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); | |
688 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
1aff3c8b | 689 | struct autofs_info *p_ino; |
1da177e4 LT |
690 | |
691 | /* This allows root to remove symlinks */ | |
d78e53c8 | 692 | if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN)) |
1da177e4 LT |
693 | return -EACCES; |
694 | ||
1aff3c8b IK |
695 | if (atomic_dec_and_test(&ino->count)) { |
696 | p_ino = autofs4_dentry_ino(dentry->d_parent); | |
697 | if (p_ino && dentry->d_parent != dentry) | |
698 | atomic_dec(&p_ino->count); | |
699 | } | |
1da177e4 LT |
700 | dput(ino->dentry); |
701 | ||
702 | dentry->d_inode->i_size = 0; | |
ce71ec36 | 703 | clear_nlink(dentry->d_inode); |
1da177e4 LT |
704 | |
705 | dir->i_mtime = CURRENT_TIME; | |
706 | ||
f50b6f86 | 707 | spin_lock(&dcache_lock); |
5f6f4f28 | 708 | spin_lock(&sbi->lookup_lock); |
25767378 IK |
709 | if (list_empty(&ino->expiring)) |
710 | list_add(&ino->expiring, &sbi->expiring_list); | |
5f6f4f28 | 711 | spin_unlock(&sbi->lookup_lock); |
f50b6f86 IK |
712 | spin_lock(&dentry->d_lock); |
713 | __d_drop(dentry); | |
714 | spin_unlock(&dentry->d_lock); | |
715 | spin_unlock(&dcache_lock); | |
1da177e4 LT |
716 | |
717 | return 0; | |
718 | } | |
719 | ||
720 | static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry) | |
721 | { | |
722 | struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); | |
723 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
1aff3c8b | 724 | struct autofs_info *p_ino; |
1da177e4 | 725 | |
f50b6f86 IK |
726 | DPRINTK("dentry %p, removing %.*s", |
727 | dentry, dentry->d_name.len, dentry->d_name.name); | |
728 | ||
1da177e4 LT |
729 | if (!autofs4_oz_mode(sbi)) |
730 | return -EACCES; | |
731 | ||
732 | spin_lock(&dcache_lock); | |
733 | if (!list_empty(&dentry->d_subdirs)) { | |
734 | spin_unlock(&dcache_lock); | |
735 | return -ENOTEMPTY; | |
736 | } | |
5f6f4f28 | 737 | spin_lock(&sbi->lookup_lock); |
25767378 IK |
738 | if (list_empty(&ino->expiring)) |
739 | list_add(&ino->expiring, &sbi->expiring_list); | |
5f6f4f28 | 740 | spin_unlock(&sbi->lookup_lock); |
1da177e4 LT |
741 | spin_lock(&dentry->d_lock); |
742 | __d_drop(dentry); | |
743 | spin_unlock(&dentry->d_lock); | |
744 | spin_unlock(&dcache_lock); | |
745 | ||
1aff3c8b IK |
746 | if (atomic_dec_and_test(&ino->count)) { |
747 | p_ino = autofs4_dentry_ino(dentry->d_parent); | |
748 | if (p_ino && dentry->d_parent != dentry) | |
749 | atomic_dec(&p_ino->count); | |
750 | } | |
1da177e4 | 751 | dput(ino->dentry); |
1da177e4 | 752 | dentry->d_inode->i_size = 0; |
ce71ec36 | 753 | clear_nlink(dentry->d_inode); |
1da177e4 LT |
754 | |
755 | if (dir->i_nlink) | |
9a53c3a7 | 756 | drop_nlink(dir); |
1da177e4 LT |
757 | |
758 | return 0; | |
759 | } | |
760 | ||
761 | static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
762 | { | |
763 | struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); | |
764 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
1aff3c8b | 765 | struct autofs_info *p_ino; |
1da177e4 LT |
766 | struct inode *inode; |
767 | ||
d78e53c8 | 768 | if (!autofs4_oz_mode(sbi)) |
1da177e4 LT |
769 | return -EACCES; |
770 | ||
771 | DPRINTK("dentry %p, creating %.*s", | |
772 | dentry, dentry->d_name.len, dentry->d_name.name); | |
773 | ||
774 | ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555); | |
25767378 IK |
775 | if (!ino) |
776 | return -ENOMEM; | |
777 | ||
778 | spin_lock(&sbi->lookup_lock); | |
779 | if (!list_empty(&ino->active)) | |
780 | list_del_init(&ino->active); | |
781 | spin_unlock(&sbi->lookup_lock); | |
1da177e4 LT |
782 | |
783 | inode = autofs4_get_inode(dir->i_sb, ino); | |
25767378 IK |
784 | if (!inode) { |
785 | if (!dentry->d_fsdata) | |
786 | kfree(ino); | |
787 | return -ENOMEM; | |
788 | } | |
1864f7bd | 789 | d_add(dentry, inode); |
1da177e4 LT |
790 | |
791 | if (dir == dir->i_sb->s_root->d_inode) | |
792 | dentry->d_op = &autofs4_root_dentry_operations; | |
793 | else | |
794 | dentry->d_op = &autofs4_dentry_operations; | |
795 | ||
796 | dentry->d_fsdata = ino; | |
797 | ino->dentry = dget(dentry); | |
1aff3c8b IK |
798 | atomic_inc(&ino->count); |
799 | p_ino = autofs4_dentry_ino(dentry->d_parent); | |
800 | if (p_ino && dentry->d_parent != dentry) | |
801 | atomic_inc(&p_ino->count); | |
1da177e4 | 802 | ino->inode = inode; |
d8c76e6f | 803 | inc_nlink(dir); |
1da177e4 LT |
804 | dir->i_mtime = CURRENT_TIME; |
805 | ||
806 | return 0; | |
807 | } | |
808 | ||
809 | /* Get/set timeout ioctl() operation */ | |
810 | static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi, | |
811 | unsigned long __user *p) | |
812 | { | |
813 | int rv; | |
814 | unsigned long ntimeout; | |
815 | ||
d78e53c8 SB |
816 | if ((rv = get_user(ntimeout, p)) || |
817 | (rv = put_user(sbi->exp_timeout/HZ, p))) | |
1da177e4 LT |
818 | return rv; |
819 | ||
d78e53c8 | 820 | if (ntimeout > ULONG_MAX/HZ) |
1da177e4 LT |
821 | sbi->exp_timeout = 0; |
822 | else | |
823 | sbi->exp_timeout = ntimeout * HZ; | |
824 | ||
825 | return 0; | |
826 | } | |
827 | ||
828 | /* Return protocol version */ | |
829 | static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int __user *p) | |
830 | { | |
831 | return put_user(sbi->version, p); | |
832 | } | |
833 | ||
834 | /* Return protocol sub version */ | |
835 | static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p) | |
836 | { | |
837 | return put_user(sbi->sub_version, p); | |
838 | } | |
839 | ||
1da177e4 LT |
840 | /* |
841 | * Tells the daemon whether it can umount the autofs mount. | |
842 | */ | |
843 | static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p) | |
844 | { | |
845 | int status = 0; | |
846 | ||
e3474a8e | 847 | if (may_umount(mnt)) |
1da177e4 LT |
848 | status = 1; |
849 | ||
850 | DPRINTK("returning %d", status); | |
851 | ||
852 | status = put_user(status, p); | |
853 | ||
854 | return status; | |
855 | } | |
856 | ||
857 | /* Identify autofs4_dentries - this is so we can tell if there's | |
858 | an extra dentry refcount or not. We only hold a refcount on the | |
859 | dentry if its non-negative (ie, d_inode != NULL) | |
860 | */ | |
861 | int is_autofs4_dentry(struct dentry *dentry) | |
862 | { | |
863 | return dentry && dentry->d_inode && | |
864 | (dentry->d_op == &autofs4_root_dentry_operations || | |
865 | dentry->d_op == &autofs4_dentry_operations) && | |
866 | dentry->d_fsdata != NULL; | |
867 | } | |
868 | ||
869 | /* | |
870 | * ioctl()'s on the root directory is the chief method for the daemon to | |
871 | * generate kernel reactions | |
872 | */ | |
873 | static int autofs4_root_ioctl(struct inode *inode, struct file *filp, | |
874 | unsigned int cmd, unsigned long arg) | |
875 | { | |
876 | struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb); | |
877 | void __user *p = (void __user *)arg; | |
878 | ||
879 | DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u", | |
a47afb0f | 880 | cmd,arg,sbi,task_pgrp_nr(current)); |
1da177e4 | 881 | |
d78e53c8 SB |
882 | if (_IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) || |
883 | _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT) | |
1da177e4 LT |
884 | return -ENOTTY; |
885 | ||
d78e53c8 | 886 | if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN)) |
1da177e4 LT |
887 | return -EPERM; |
888 | ||
889 | switch(cmd) { | |
890 | case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */ | |
891 | return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0); | |
892 | case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */ | |
893 | return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT); | |
894 | case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */ | |
895 | autofs4_catatonic_mode(sbi); | |
896 | return 0; | |
897 | case AUTOFS_IOC_PROTOVER: /* Get protocol version */ | |
898 | return autofs4_get_protover(sbi, p); | |
899 | case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */ | |
900 | return autofs4_get_protosubver(sbi, p); | |
901 | case AUTOFS_IOC_SETTIMEOUT: | |
902 | return autofs4_get_set_timeout(sbi, p); | |
903 | ||
1da177e4 | 904 | case AUTOFS_IOC_ASKUMOUNT: |
a4669ed8 | 905 | return autofs4_ask_umount(filp->f_path.mnt, p); |
1da177e4 LT |
906 | |
907 | /* return a single thing to expire */ | |
908 | case AUTOFS_IOC_EXPIRE: | |
a4669ed8 | 909 | return autofs4_expire_run(inode->i_sb,filp->f_path.mnt,sbi, p); |
1da177e4 LT |
910 | /* same as above, but can send multiple expires through pipe */ |
911 | case AUTOFS_IOC_EXPIRE_MULTI: | |
a4669ed8 | 912 | return autofs4_expire_multi(inode->i_sb,filp->f_path.mnt,sbi, p); |
1da177e4 LT |
913 | |
914 | default: | |
915 | return -ENOSYS; | |
916 | } | |
917 | } |