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 | ||
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 | ||
36b6413e IK |
107 | static unsigned int autofs4_need_mount(unsigned int flags) |
108 | { | |
109 | unsigned int res = 0; | |
110 | if (flags & (TRIGGER_FLAGS | TRIGGER_INTENTS)) | |
111 | res = 1; | |
112 | return res; | |
113 | } | |
114 | ||
1da177e4 LT |
115 | static int autofs4_dir_open(struct inode *inode, struct file *file) |
116 | { | |
a4669ed8 | 117 | struct dentry *dentry = file->f_path.dentry; |
1da177e4 | 118 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); |
f360ce3b | 119 | |
1da177e4 LT |
120 | DPRINTK("file=%p dentry=%p %.*s", |
121 | file, dentry, dentry->d_name.len, dentry->d_name.name); | |
122 | ||
123 | if (autofs4_oz_mode(sbi)) | |
124 | goto out; | |
125 | ||
ff9cd499 IK |
126 | /* |
127 | * An empty directory in an autofs file system is always a | |
128 | * mount point. The daemon must have failed to mount this | |
129 | * during lookup so it doesn't exist. This can happen, for | |
130 | * example, if user space returns an incorrect status for a | |
131 | * mount request. Otherwise we're doing a readdir on the | |
132 | * autofs file system so just let the libfs routines handle | |
133 | * it. | |
134 | */ | |
135 | spin_lock(&dcache_lock); | |
136 | if (!d_mountpoint(dentry) && __simple_empty(dentry)) { | |
1da177e4 | 137 | spin_unlock(&dcache_lock); |
ff9cd499 | 138 | return -ENOENT; |
1da177e4 | 139 | } |
ff9cd499 | 140 | spin_unlock(&dcache_lock); |
1da177e4 | 141 | |
1da177e4 | 142 | out: |
ff9cd499 | 143 | return dcache_dir_open(inode, file); |
1da177e4 LT |
144 | } |
145 | ||
862b110f | 146 | static int try_to_fill_dentry(struct dentry *dentry, int flags) |
1da177e4 | 147 | { |
862b110f | 148 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); |
718c604a | 149 | struct autofs_info *ino = autofs4_dentry_ino(dentry); |
9d2de6ad | 150 | int status; |
1da177e4 | 151 | |
1da177e4 LT |
152 | DPRINTK("dentry=%p %.*s ino=%p", |
153 | dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_inode); | |
154 | ||
718c604a IK |
155 | /* |
156 | * Wait for a pending mount, triggering one if there | |
157 | * isn't one already | |
158 | */ | |
1da177e4 LT |
159 | if (dentry->d_inode == NULL) { |
160 | DPRINTK("waiting for mount name=%.*s", | |
161 | dentry->d_name.len, dentry->d_name.name); | |
162 | ||
163 | status = autofs4_wait(sbi, dentry, NFY_MOUNT); | |
718c604a | 164 | |
1da177e4 LT |
165 | DPRINTK("mount done status=%d", status); |
166 | ||
1da177e4 LT |
167 | /* Turn this into a real negative dentry? */ |
168 | if (status == -ENOENT) { | |
aa952eb2 IK |
169 | spin_lock(&sbi->fs_lock); |
170 | ino->flags &= ~AUTOFS_INF_PENDING; | |
171 | spin_unlock(&sbi->fs_lock); | |
34ca959c | 172 | return status; |
1da177e4 LT |
173 | } else if (status) { |
174 | /* Return a negative dentry, but leave it "pending" */ | |
34ca959c | 175 | return status; |
1da177e4 LT |
176 | } |
177 | /* Trigger mount for path component or follow link */ | |
aa952eb2 | 178 | } else if (ino->flags & AUTOFS_INF_PENDING || |
36b6413e | 179 | autofs4_need_mount(flags) || |
1da177e4 LT |
180 | current->link_count) { |
181 | DPRINTK("waiting for mount name=%.*s", | |
182 | dentry->d_name.len, dentry->d_name.name); | |
183 | ||
aa952eb2 IK |
184 | spin_lock(&sbi->fs_lock); |
185 | ino->flags |= AUTOFS_INF_PENDING; | |
186 | spin_unlock(&sbi->fs_lock); | |
1da177e4 LT |
187 | status = autofs4_wait(sbi, dentry, NFY_MOUNT); |
188 | ||
189 | DPRINTK("mount done status=%d", status); | |
190 | ||
191 | if (status) { | |
aa952eb2 IK |
192 | spin_lock(&sbi->fs_lock); |
193 | ino->flags &= ~AUTOFS_INF_PENDING; | |
194 | spin_unlock(&sbi->fs_lock); | |
34ca959c | 195 | return status; |
1da177e4 LT |
196 | } |
197 | } | |
198 | ||
e0a7aae9 IK |
199 | /* Initialize expiry counter after successful mount */ |
200 | if (ino) | |
201 | ino->last_used = jiffies; | |
202 | ||
aa952eb2 IK |
203 | spin_lock(&sbi->fs_lock); |
204 | ino->flags &= ~AUTOFS_INF_PENDING; | |
205 | spin_unlock(&sbi->fs_lock); | |
03379044 | 206 | |
9d2de6ad | 207 | return 0; |
34ca959c IK |
208 | } |
209 | ||
210 | /* For autofs direct mounts the follow link triggers the mount */ | |
211 | static void *autofs4_follow_link(struct dentry *dentry, struct nameidata *nd) | |
212 | { | |
213 | struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); | |
a5370553 | 214 | struct autofs_info *ino = autofs4_dentry_ino(dentry); |
34ca959c IK |
215 | int oz_mode = autofs4_oz_mode(sbi); |
216 | unsigned int lookup_type; | |
217 | int status; | |
218 | ||
219 | DPRINTK("dentry=%p %.*s oz_mode=%d nd->flags=%d", | |
220 | dentry, dentry->d_name.len, dentry->d_name.name, oz_mode, | |
221 | nd->flags); | |
6e60a9ab IK |
222 | /* |
223 | * For an expire of a covered direct or offset mount we need | |
9393bd07 | 224 | * to break out of follow_down() at the autofs mount trigger |
6e60a9ab IK |
225 | * (d_mounted--), so we can see the expiring flag, and manage |
226 | * the blocking and following here until the expire is completed. | |
227 | */ | |
228 | if (oz_mode) { | |
229 | spin_lock(&sbi->fs_lock); | |
230 | if (ino->flags & AUTOFS_INF_EXPIRING) { | |
231 | spin_unlock(&sbi->fs_lock); | |
232 | /* Follow down to our covering mount. */ | |
9393bd07 | 233 | if (!follow_down(&nd->path)) |
6e60a9ab | 234 | goto done; |
ec6e8c7d | 235 | goto follow; |
6e60a9ab IK |
236 | } |
237 | spin_unlock(&sbi->fs_lock); | |
34ca959c | 238 | goto done; |
6e60a9ab | 239 | } |
34ca959c | 240 | |
6e60a9ab | 241 | /* If an expire request is pending everyone must wait. */ |
06a35985 | 242 | autofs4_expire_wait(dentry); |
871f9434 | 243 | |
6e60a9ab | 244 | /* We trigger a mount for almost all flags */ |
36b6413e | 245 | lookup_type = autofs4_need_mount(nd->flags); |
aa952eb2 IK |
246 | spin_lock(&sbi->fs_lock); |
247 | spin_lock(&dcache_lock); | |
248 | if (!(lookup_type || ino->flags & AUTOFS_INF_PENDING)) { | |
249 | spin_unlock(&dcache_lock); | |
250 | spin_unlock(&sbi->fs_lock); | |
ec6e8c7d | 251 | goto follow; |
aa952eb2 | 252 | } |
6e60a9ab | 253 | |
871f9434 | 254 | /* |
6e60a9ab IK |
255 | * If the dentry contains directories then it is an autofs |
256 | * multi-mount with no root mount offset. So don't try to | |
257 | * mount it again. | |
871f9434 | 258 | */ |
aa952eb2 | 259 | if (ino->flags & AUTOFS_INF_PENDING || |
26e81b31 | 260 | (!d_mountpoint(dentry) && __simple_empty(dentry))) { |
871f9434 | 261 | spin_unlock(&dcache_lock); |
aa952eb2 | 262 | spin_unlock(&sbi->fs_lock); |
871f9434 IK |
263 | |
264 | status = try_to_fill_dentry(dentry, 0); | |
265 | if (status) | |
266 | goto out_error; | |
267 | ||
6e60a9ab | 268 | goto follow; |
34ca959c | 269 | } |
871f9434 | 270 | spin_unlock(&dcache_lock); |
aa952eb2 | 271 | spin_unlock(&sbi->fs_lock); |
6e60a9ab IK |
272 | follow: |
273 | /* | |
274 | * If there is no root mount it must be an autofs | |
275 | * multi-mount with no root offset so we don't need | |
276 | * to follow it. | |
277 | */ | |
278 | if (d_mountpoint(dentry)) { | |
9393bd07 | 279 | if (!autofs4_follow_mount(&nd->path)) { |
6e60a9ab IK |
280 | status = -ENOENT; |
281 | goto out_error; | |
282 | } | |
283 | } | |
34ca959c IK |
284 | |
285 | done: | |
286 | return NULL; | |
287 | ||
288 | out_error: | |
1d957f9b | 289 | path_put(&nd->path); |
34ca959c | 290 | return ERR_PTR(status); |
1da177e4 LT |
291 | } |
292 | ||
293 | /* | |
294 | * Revalidate is called on every cache lookup. Some of those | |
295 | * cache lookups may actually happen while the dentry is not | |
296 | * yet completely filled in, and revalidate has to delay such | |
297 | * lookups.. | |
298 | */ | |
718c604a | 299 | static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd) |
1da177e4 | 300 | { |
718c604a | 301 | struct inode *dir = dentry->d_parent->d_inode; |
1da177e4 LT |
302 | struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); |
303 | int oz_mode = autofs4_oz_mode(sbi); | |
304 | int flags = nd ? nd->flags : 0; | |
bcdc5e01 | 305 | int status = 1; |
1da177e4 LT |
306 | |
307 | /* Pending dentry */ | |
97e7449a | 308 | spin_lock(&sbi->fs_lock); |
1da177e4 | 309 | if (autofs4_ispending(dentry)) { |
bcdc5e01 | 310 | /* The daemon never causes a mount to trigger */ |
97e7449a IK |
311 | spin_unlock(&sbi->fs_lock); |
312 | ||
bcdc5e01 IK |
313 | if (oz_mode) |
314 | return 1; | |
315 | ||
06a35985 IK |
316 | /* |
317 | * If the directory has gone away due to an expire | |
318 | * we have been called as ->d_revalidate() and so | |
319 | * we need to return false and proceed to ->lookup(). | |
320 | */ | |
321 | if (autofs4_expire_wait(dentry) == -EAGAIN) | |
322 | return 0; | |
323 | ||
bcdc5e01 IK |
324 | /* |
325 | * A zero status is success otherwise we have a | |
326 | * negative error code. | |
327 | */ | |
328 | status = try_to_fill_dentry(dentry, flags); | |
329 | if (status == 0) | |
f50b6f86 IK |
330 | return 1; |
331 | ||
bcdc5e01 | 332 | return status; |
1da177e4 | 333 | } |
97e7449a | 334 | spin_unlock(&sbi->fs_lock); |
1da177e4 LT |
335 | |
336 | /* Negative dentry.. invalidate if "old" */ | |
337 | if (dentry->d_inode == NULL) | |
2d753e62 | 338 | return 0; |
1da177e4 LT |
339 | |
340 | /* Check for a non-mountpoint directory with no contents */ | |
341 | spin_lock(&dcache_lock); | |
342 | if (S_ISDIR(dentry->d_inode->i_mode) && | |
343 | !d_mountpoint(dentry) && | |
90a59c7c | 344 | __simple_empty(dentry)) { |
1da177e4 LT |
345 | DPRINTK("dentry=%p %.*s, emptydir", |
346 | dentry, dentry->d_name.len, dentry->d_name.name); | |
347 | spin_unlock(&dcache_lock); | |
97e7449a | 348 | |
bcdc5e01 IK |
349 | /* The daemon never causes a mount to trigger */ |
350 | if (oz_mode) | |
351 | return 1; | |
352 | ||
353 | /* | |
354 | * A zero status is success otherwise we have a | |
355 | * negative error code. | |
356 | */ | |
357 | status = try_to_fill_dentry(dentry, flags); | |
358 | if (status == 0) | |
359 | return 1; | |
360 | ||
361 | return status; | |
1da177e4 LT |
362 | } |
363 | spin_unlock(&dcache_lock); | |
364 | ||
1da177e4 LT |
365 | return 1; |
366 | } | |
367 | ||
34ca959c | 368 | void autofs4_dentry_release(struct dentry *de) |
1da177e4 LT |
369 | { |
370 | struct autofs_info *inf; | |
371 | ||
372 | DPRINTK("releasing %p", de); | |
373 | ||
374 | inf = autofs4_dentry_ino(de); | |
375 | de->d_fsdata = NULL; | |
376 | ||
377 | if (inf) { | |
f50b6f86 IK |
378 | struct autofs_sb_info *sbi = autofs4_sbi(de->d_sb); |
379 | ||
f50b6f86 | 380 | if (sbi) { |
5f6f4f28 | 381 | spin_lock(&sbi->lookup_lock); |
25767378 IK |
382 | if (!list_empty(&inf->active)) |
383 | list_del(&inf->active); | |
5f6f4f28 IK |
384 | if (!list_empty(&inf->expiring)) |
385 | list_del(&inf->expiring); | |
386 | spin_unlock(&sbi->lookup_lock); | |
f50b6f86 IK |
387 | } |
388 | ||
c3724b12 JM |
389 | inf->dentry = NULL; |
390 | inf->inode = NULL; | |
391 | ||
1da177e4 LT |
392 | autofs4_free_ino(inf); |
393 | } | |
394 | } | |
395 | ||
396 | /* For dentries of directories in the root dir */ | |
08f11513 | 397 | static const struct dentry_operations autofs4_root_dentry_operations = { |
1da177e4 LT |
398 | .d_revalidate = autofs4_revalidate, |
399 | .d_release = autofs4_dentry_release, | |
400 | }; | |
401 | ||
402 | /* For other dentries */ | |
08f11513 | 403 | static const struct dentry_operations autofs4_dentry_operations = { |
1da177e4 LT |
404 | .d_revalidate = autofs4_revalidate, |
405 | .d_release = autofs4_dentry_release, | |
406 | }; | |
407 | ||
25767378 IK |
408 | static struct dentry *autofs4_lookup_active(struct autofs_sb_info *sbi, struct dentry *parent, struct qstr *name) |
409 | { | |
410 | unsigned int len = name->len; | |
411 | unsigned int hash = name->hash; | |
412 | const unsigned char *str = name->name; | |
413 | struct list_head *p, *head; | |
414 | ||
415 | spin_lock(&dcache_lock); | |
416 | spin_lock(&sbi->lookup_lock); | |
417 | head = &sbi->active_list; | |
418 | list_for_each(p, head) { | |
419 | struct autofs_info *ino; | |
420 | struct dentry *dentry; | |
421 | struct qstr *qstr; | |
422 | ||
423 | ino = list_entry(p, struct autofs_info, active); | |
424 | dentry = ino->dentry; | |
425 | ||
426 | spin_lock(&dentry->d_lock); | |
427 | ||
428 | /* Already gone? */ | |
429 | if (atomic_read(&dentry->d_count) == 0) | |
430 | goto next; | |
431 | ||
432 | qstr = &dentry->d_name; | |
433 | ||
434 | if (dentry->d_name.hash != hash) | |
435 | goto next; | |
436 | if (dentry->d_parent != parent) | |
437 | goto next; | |
438 | ||
439 | if (qstr->len != len) | |
440 | goto next; | |
441 | if (memcmp(qstr->name, str, len)) | |
442 | goto next; | |
443 | ||
444 | if (d_unhashed(dentry)) { | |
445 | dget(dentry); | |
446 | spin_unlock(&dentry->d_lock); | |
447 | spin_unlock(&sbi->lookup_lock); | |
448 | spin_unlock(&dcache_lock); | |
449 | return dentry; | |
450 | } | |
451 | next: | |
452 | spin_unlock(&dentry->d_lock); | |
453 | } | |
454 | spin_unlock(&sbi->lookup_lock); | |
455 | spin_unlock(&dcache_lock); | |
456 | ||
457 | return NULL; | |
458 | } | |
459 | ||
5f6f4f28 | 460 | static struct dentry *autofs4_lookup_expiring(struct autofs_sb_info *sbi, struct dentry *parent, struct qstr *name) |
f50b6f86 IK |
461 | { |
462 | unsigned int len = name->len; | |
463 | unsigned int hash = name->hash; | |
464 | const unsigned char *str = name->name; | |
465 | struct list_head *p, *head; | |
466 | ||
467 | spin_lock(&dcache_lock); | |
5f6f4f28 IK |
468 | spin_lock(&sbi->lookup_lock); |
469 | head = &sbi->expiring_list; | |
f50b6f86 IK |
470 | list_for_each(p, head) { |
471 | struct autofs_info *ino; | |
472 | struct dentry *dentry; | |
473 | struct qstr *qstr; | |
474 | ||
5f6f4f28 | 475 | ino = list_entry(p, struct autofs_info, expiring); |
f50b6f86 IK |
476 | dentry = ino->dentry; |
477 | ||
478 | spin_lock(&dentry->d_lock); | |
479 | ||
480 | /* Bad luck, we've already been dentry_iput */ | |
481 | if (!dentry->d_inode) | |
482 | goto next; | |
483 | ||
484 | qstr = &dentry->d_name; | |
485 | ||
486 | if (dentry->d_name.hash != hash) | |
487 | goto next; | |
488 | if (dentry->d_parent != parent) | |
489 | goto next; | |
490 | ||
491 | if (qstr->len != len) | |
492 | goto next; | |
493 | if (memcmp(qstr->name, str, len)) | |
494 | goto next; | |
495 | ||
496 | if (d_unhashed(dentry)) { | |
f50b6f86 | 497 | dget(dentry); |
f50b6f86 | 498 | spin_unlock(&dentry->d_lock); |
5f6f4f28 | 499 | spin_unlock(&sbi->lookup_lock); |
f50b6f86 IK |
500 | spin_unlock(&dcache_lock); |
501 | return dentry; | |
502 | } | |
503 | next: | |
504 | spin_unlock(&dentry->d_lock); | |
505 | } | |
5f6f4f28 | 506 | spin_unlock(&sbi->lookup_lock); |
f50b6f86 IK |
507 | spin_unlock(&dcache_lock); |
508 | ||
509 | return NULL; | |
510 | } | |
511 | ||
1da177e4 LT |
512 | /* Lookups in the root directory */ |
513 | static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) | |
514 | { | |
515 | struct autofs_sb_info *sbi; | |
25767378 IK |
516 | struct autofs_info *ino; |
517 | struct dentry *expiring, *unhashed; | |
1da177e4 LT |
518 | int oz_mode; |
519 | ||
520 | DPRINTK("name = %.*s", | |
521 | dentry->d_name.len, dentry->d_name.name); | |
522 | ||
718c604a | 523 | /* File name too long to exist */ |
1da177e4 | 524 | if (dentry->d_name.len > NAME_MAX) |
718c604a | 525 | return ERR_PTR(-ENAMETOOLONG); |
1da177e4 LT |
526 | |
527 | sbi = autofs4_sbi(dir->i_sb); | |
1da177e4 | 528 | oz_mode = autofs4_oz_mode(sbi); |
718c604a | 529 | |
1da177e4 | 530 | DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d", |
a47afb0f | 531 | current->pid, task_pgrp_nr(current), sbi->catatonic, oz_mode); |
1da177e4 | 532 | |
25767378 | 533 | unhashed = autofs4_lookup_active(sbi, dentry->d_parent, &dentry->d_name); |
aa952eb2 | 534 | if (unhashed) { |
25767378 | 535 | dentry = unhashed; |
aa952eb2 IK |
536 | ino = autofs4_dentry_ino(dentry); |
537 | } else { | |
25767378 IK |
538 | /* |
539 | * Mark the dentry incomplete but don't hash it. We do this | |
540 | * to serialize our inode creation operations (symlink and | |
541 | * mkdir) which prevents deadlock during the callback to | |
542 | * the daemon. Subsequent user space lookups for the same | |
543 | * dentry are placed on the wait queue while the daemon | |
544 | * itself is allowed passage unresticted so the create | |
545 | * operation itself can then hash the dentry. Finally, | |
546 | * we check for the hashed dentry and return the newly | |
547 | * hashed dentry. | |
548 | */ | |
549 | dentry->d_op = &autofs4_root_dentry_operations; | |
550 | ||
551 | /* | |
552 | * And we need to ensure that the same dentry is used for | |
553 | * all following lookup calls until it is hashed so that | |
554 | * the dentry flags are persistent throughout the request. | |
555 | */ | |
556 | ino = autofs4_init_ino(NULL, sbi, 0555); | |
557 | if (!ino) | |
558 | return ERR_PTR(-ENOMEM); | |
559 | ||
560 | dentry->d_fsdata = ino; | |
561 | ino->dentry = dentry; | |
562 | ||
4f8427d1 | 563 | autofs4_add_active(dentry); |
5f6f4f28 | 564 | |
25767378 IK |
565 | d_instantiate(dentry, NULL); |
566 | } | |
5f6f4f28 | 567 | |
1da177e4 | 568 | if (!oz_mode) { |
8f63aaa8 IK |
569 | mutex_unlock(&dir->i_mutex); |
570 | expiring = autofs4_lookup_expiring(sbi, | |
571 | dentry->d_parent, | |
572 | &dentry->d_name); | |
573 | if (expiring) { | |
574 | /* | |
575 | * If we are racing with expire the request might not | |
576 | * be quite complete but the directory has been removed | |
577 | * so it must have been successful, so just wait for it. | |
578 | */ | |
8f63aaa8 | 579 | autofs4_expire_wait(expiring); |
c4cd70b3 | 580 | autofs4_del_expiring(expiring); |
8f63aaa8 IK |
581 | dput(expiring); |
582 | } | |
583 | ||
aa952eb2 IK |
584 | spin_lock(&sbi->fs_lock); |
585 | ino->flags |= AUTOFS_INF_PENDING; | |
586 | spin_unlock(&sbi->fs_lock); | |
8f63aaa8 | 587 | if (dentry->d_op && dentry->d_op->d_revalidate) |
c432c258 | 588 | (dentry->d_op->d_revalidate)(dentry, nd); |
8f63aaa8 | 589 | mutex_lock(&dir->i_mutex); |
1da177e4 LT |
590 | } |
591 | ||
592 | /* | |
593 | * If we are still pending, check if we had to handle | |
594 | * a signal. If so we can force a restart.. | |
595 | */ | |
aa952eb2 | 596 | if (ino->flags & AUTOFS_INF_PENDING) { |
1da177e4 LT |
597 | /* See if we were interrupted */ |
598 | if (signal_pending(current)) { | |
599 | sigset_t *sigset = ¤t->pending.signal; | |
600 | if (sigismember (sigset, SIGKILL) || | |
601 | sigismember (sigset, SIGQUIT) || | |
602 | sigismember (sigset, SIGINT)) { | |
25767378 IK |
603 | if (unhashed) |
604 | dput(unhashed); | |
1da177e4 LT |
605 | return ERR_PTR(-ERESTARTNOINTR); |
606 | } | |
607 | } | |
25767378 | 608 | if (!oz_mode) { |
aa952eb2 IK |
609 | spin_lock(&sbi->fs_lock); |
610 | ino->flags &= ~AUTOFS_INF_PENDING; | |
611 | spin_unlock(&sbi->fs_lock); | |
25767378 | 612 | } |
1da177e4 LT |
613 | } |
614 | ||
615 | /* | |
616 | * If this dentry is unhashed, then we shouldn't honour this | |
c9ffec48 IK |
617 | * lookup. Returning ENOENT here doesn't do the right thing |
618 | * for all system calls, but it should be OK for the operations | |
619 | * we permit from an autofs. | |
1da177e4 | 620 | */ |
1864f7bd | 621 | if (!oz_mode && d_unhashed(dentry)) { |
c9ffec48 IK |
622 | /* |
623 | * A user space application can (and has done in the past) | |
624 | * remove and re-create this directory during the callback. | |
625 | * This can leave us with an unhashed dentry, but a | |
626 | * successful mount! So we need to perform another | |
627 | * cached lookup in case the dentry now exists. | |
628 | */ | |
629 | struct dentry *parent = dentry->d_parent; | |
630 | struct dentry *new = d_lookup(parent, &dentry->d_name); | |
631 | if (new != NULL) | |
632 | dentry = new; | |
633 | else | |
634 | dentry = ERR_PTR(-ENOENT); | |
635 | ||
25767378 IK |
636 | if (unhashed) |
637 | dput(unhashed); | |
638 | ||
c9ffec48 | 639 | return dentry; |
f50b6f86 IK |
640 | } |
641 | ||
25767378 IK |
642 | if (unhashed) |
643 | return unhashed; | |
644 | ||
1da177e4 LT |
645 | return NULL; |
646 | } | |
647 | ||
648 | static int autofs4_dir_symlink(struct inode *dir, | |
649 | struct dentry *dentry, | |
650 | const char *symname) | |
651 | { | |
652 | struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); | |
653 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
1aff3c8b | 654 | struct autofs_info *p_ino; |
1da177e4 LT |
655 | struct inode *inode; |
656 | char *cp; | |
657 | ||
658 | DPRINTK("%s <- %.*s", symname, | |
659 | dentry->d_name.len, dentry->d_name.name); | |
660 | ||
661 | if (!autofs4_oz_mode(sbi)) | |
662 | return -EACCES; | |
663 | ||
664 | ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555); | |
25767378 IK |
665 | if (!ino) |
666 | return -ENOMEM; | |
1da177e4 | 667 | |
4f8427d1 | 668 | autofs4_del_active(dentry); |
1da177e4 | 669 | |
ef581a74 | 670 | ino->size = strlen(symname); |
25767378 IK |
671 | cp = kmalloc(ino->size + 1, GFP_KERNEL); |
672 | if (!cp) { | |
673 | if (!dentry->d_fsdata) | |
674 | kfree(ino); | |
675 | return -ENOMEM; | |
1da177e4 LT |
676 | } |
677 | ||
678 | strcpy(cp, symname); | |
679 | ||
680 | inode = autofs4_get_inode(dir->i_sb, ino); | |
25767378 IK |
681 | if (!inode) { |
682 | kfree(cp); | |
683 | if (!dentry->d_fsdata) | |
684 | kfree(ino); | |
685 | return -ENOMEM; | |
686 | } | |
1864f7bd | 687 | d_add(dentry, inode); |
1da177e4 LT |
688 | |
689 | if (dir == dir->i_sb->s_root->d_inode) | |
690 | dentry->d_op = &autofs4_root_dentry_operations; | |
691 | else | |
692 | dentry->d_op = &autofs4_dentry_operations; | |
693 | ||
694 | dentry->d_fsdata = ino; | |
695 | ino->dentry = dget(dentry); | |
1aff3c8b IK |
696 | atomic_inc(&ino->count); |
697 | p_ino = autofs4_dentry_ino(dentry->d_parent); | |
698 | if (p_ino && dentry->d_parent != dentry) | |
699 | atomic_inc(&p_ino->count); | |
1da177e4 LT |
700 | ino->inode = inode; |
701 | ||
25767378 | 702 | ino->u.symlink = cp; |
1da177e4 LT |
703 | dir->i_mtime = CURRENT_TIME; |
704 | ||
705 | return 0; | |
706 | } | |
707 | ||
708 | /* | |
709 | * NOTE! | |
710 | * | |
711 | * Normal filesystems would do a "d_delete()" to tell the VFS dcache | |
712 | * that the file no longer exists. However, doing that means that the | |
713 | * VFS layer can turn the dentry into a negative dentry. We don't want | |
f50b6f86 | 714 | * this, because the unlink is probably the result of an expire. |
5f6f4f28 IK |
715 | * We simply d_drop it and add it to a expiring list in the super block, |
716 | * which allows the dentry lookup to check for an incomplete expire. | |
1da177e4 LT |
717 | * |
718 | * If a process is blocked on the dentry waiting for the expire to finish, | |
719 | * it will invalidate the dentry and try to mount with a new one. | |
720 | * | |
721 | * Also see autofs4_dir_rmdir().. | |
722 | */ | |
723 | static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry) | |
724 | { | |
725 | struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); | |
726 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
1aff3c8b | 727 | struct autofs_info *p_ino; |
1da177e4 LT |
728 | |
729 | /* This allows root to remove symlinks */ | |
d78e53c8 | 730 | if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN)) |
1da177e4 LT |
731 | return -EACCES; |
732 | ||
1aff3c8b IK |
733 | if (atomic_dec_and_test(&ino->count)) { |
734 | p_ino = autofs4_dentry_ino(dentry->d_parent); | |
735 | if (p_ino && dentry->d_parent != dentry) | |
736 | atomic_dec(&p_ino->count); | |
737 | } | |
1da177e4 LT |
738 | dput(ino->dentry); |
739 | ||
740 | dentry->d_inode->i_size = 0; | |
ce71ec36 | 741 | clear_nlink(dentry->d_inode); |
1da177e4 LT |
742 | |
743 | dir->i_mtime = CURRENT_TIME; | |
744 | ||
f50b6f86 | 745 | spin_lock(&dcache_lock); |
c4cd70b3 | 746 | autofs4_add_expiring(dentry); |
f50b6f86 IK |
747 | spin_lock(&dentry->d_lock); |
748 | __d_drop(dentry); | |
749 | spin_unlock(&dentry->d_lock); | |
750 | spin_unlock(&dcache_lock); | |
1da177e4 LT |
751 | |
752 | return 0; | |
753 | } | |
754 | ||
755 | static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry) | |
756 | { | |
757 | struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); | |
758 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
1aff3c8b | 759 | struct autofs_info *p_ino; |
1da177e4 | 760 | |
f50b6f86 IK |
761 | DPRINTK("dentry %p, removing %.*s", |
762 | dentry, dentry->d_name.len, dentry->d_name.name); | |
763 | ||
1da177e4 LT |
764 | if (!autofs4_oz_mode(sbi)) |
765 | return -EACCES; | |
766 | ||
767 | spin_lock(&dcache_lock); | |
768 | if (!list_empty(&dentry->d_subdirs)) { | |
769 | spin_unlock(&dcache_lock); | |
770 | return -ENOTEMPTY; | |
771 | } | |
c4cd70b3 | 772 | autofs4_add_expiring(dentry); |
1da177e4 LT |
773 | spin_lock(&dentry->d_lock); |
774 | __d_drop(dentry); | |
775 | spin_unlock(&dentry->d_lock); | |
776 | spin_unlock(&dcache_lock); | |
777 | ||
1aff3c8b IK |
778 | if (atomic_dec_and_test(&ino->count)) { |
779 | p_ino = autofs4_dentry_ino(dentry->d_parent); | |
780 | if (p_ino && dentry->d_parent != dentry) | |
781 | atomic_dec(&p_ino->count); | |
782 | } | |
1da177e4 | 783 | dput(ino->dentry); |
1da177e4 | 784 | dentry->d_inode->i_size = 0; |
ce71ec36 | 785 | clear_nlink(dentry->d_inode); |
1da177e4 LT |
786 | |
787 | if (dir->i_nlink) | |
9a53c3a7 | 788 | drop_nlink(dir); |
1da177e4 LT |
789 | |
790 | return 0; | |
791 | } | |
792 | ||
793 | static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
794 | { | |
795 | struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); | |
796 | struct autofs_info *ino = autofs4_dentry_ino(dentry); | |
1aff3c8b | 797 | struct autofs_info *p_ino; |
1da177e4 LT |
798 | struct inode *inode; |
799 | ||
d78e53c8 | 800 | if (!autofs4_oz_mode(sbi)) |
1da177e4 LT |
801 | return -EACCES; |
802 | ||
803 | DPRINTK("dentry %p, creating %.*s", | |
804 | dentry, dentry->d_name.len, dentry->d_name.name); | |
805 | ||
806 | ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555); | |
25767378 IK |
807 | if (!ino) |
808 | return -ENOMEM; | |
809 | ||
4f8427d1 | 810 | autofs4_del_active(dentry); |
1da177e4 LT |
811 | |
812 | inode = autofs4_get_inode(dir->i_sb, ino); | |
25767378 IK |
813 | if (!inode) { |
814 | if (!dentry->d_fsdata) | |
815 | kfree(ino); | |
816 | return -ENOMEM; | |
817 | } | |
1864f7bd | 818 | d_add(dentry, inode); |
1da177e4 LT |
819 | |
820 | if (dir == dir->i_sb->s_root->d_inode) | |
821 | dentry->d_op = &autofs4_root_dentry_operations; | |
822 | else | |
823 | dentry->d_op = &autofs4_dentry_operations; | |
824 | ||
825 | dentry->d_fsdata = ino; | |
826 | ino->dentry = dget(dentry); | |
1aff3c8b IK |
827 | atomic_inc(&ino->count); |
828 | p_ino = autofs4_dentry_ino(dentry->d_parent); | |
829 | if (p_ino && dentry->d_parent != dentry) | |
830 | atomic_inc(&p_ino->count); | |
1da177e4 | 831 | ino->inode = inode; |
d8c76e6f | 832 | inc_nlink(dir); |
1da177e4 LT |
833 | dir->i_mtime = CURRENT_TIME; |
834 | ||
835 | return 0; | |
836 | } | |
837 | ||
838 | /* Get/set timeout ioctl() operation */ | |
839 | static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi, | |
840 | unsigned long __user *p) | |
841 | { | |
842 | int rv; | |
843 | unsigned long ntimeout; | |
844 | ||
d78e53c8 SB |
845 | if ((rv = get_user(ntimeout, p)) || |
846 | (rv = put_user(sbi->exp_timeout/HZ, p))) | |
1da177e4 LT |
847 | return rv; |
848 | ||
d78e53c8 | 849 | if (ntimeout > ULONG_MAX/HZ) |
1da177e4 LT |
850 | sbi->exp_timeout = 0; |
851 | else | |
852 | sbi->exp_timeout = ntimeout * HZ; | |
853 | ||
854 | return 0; | |
855 | } | |
856 | ||
857 | /* Return protocol version */ | |
858 | static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int __user *p) | |
859 | { | |
860 | return put_user(sbi->version, p); | |
861 | } | |
862 | ||
863 | /* Return protocol sub version */ | |
864 | static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p) | |
865 | { | |
866 | return put_user(sbi->sub_version, p); | |
867 | } | |
868 | ||
1da177e4 LT |
869 | /* |
870 | * Tells the daemon whether it can umount the autofs mount. | |
871 | */ | |
872 | static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p) | |
873 | { | |
874 | int status = 0; | |
875 | ||
e3474a8e | 876 | if (may_umount(mnt)) |
1da177e4 LT |
877 | status = 1; |
878 | ||
879 | DPRINTK("returning %d", status); | |
880 | ||
881 | status = put_user(status, p); | |
882 | ||
883 | return status; | |
884 | } | |
885 | ||
886 | /* Identify autofs4_dentries - this is so we can tell if there's | |
887 | an extra dentry refcount or not. We only hold a refcount on the | |
888 | dentry if its non-negative (ie, d_inode != NULL) | |
889 | */ | |
890 | int is_autofs4_dentry(struct dentry *dentry) | |
891 | { | |
892 | return dentry && dentry->d_inode && | |
893 | (dentry->d_op == &autofs4_root_dentry_operations || | |
894 | dentry->d_op == &autofs4_dentry_operations) && | |
895 | dentry->d_fsdata != NULL; | |
896 | } | |
897 | ||
898 | /* | |
899 | * ioctl()'s on the root directory is the chief method for the daemon to | |
900 | * generate kernel reactions | |
901 | */ | |
902 | static int autofs4_root_ioctl(struct inode *inode, struct file *filp, | |
903 | unsigned int cmd, unsigned long arg) | |
904 | { | |
905 | struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb); | |
906 | void __user *p = (void __user *)arg; | |
907 | ||
908 | DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u", | |
a47afb0f | 909 | cmd,arg,sbi,task_pgrp_nr(current)); |
1da177e4 | 910 | |
d78e53c8 SB |
911 | if (_IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) || |
912 | _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT) | |
1da177e4 LT |
913 | return -ENOTTY; |
914 | ||
d78e53c8 | 915 | if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN)) |
1da177e4 LT |
916 | return -EPERM; |
917 | ||
918 | switch(cmd) { | |
919 | case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */ | |
920 | return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0); | |
921 | case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */ | |
922 | return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT); | |
923 | case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */ | |
924 | autofs4_catatonic_mode(sbi); | |
925 | return 0; | |
926 | case AUTOFS_IOC_PROTOVER: /* Get protocol version */ | |
927 | return autofs4_get_protover(sbi, p); | |
928 | case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */ | |
929 | return autofs4_get_protosubver(sbi, p); | |
930 | case AUTOFS_IOC_SETTIMEOUT: | |
931 | return autofs4_get_set_timeout(sbi, p); | |
932 | ||
1da177e4 | 933 | case AUTOFS_IOC_ASKUMOUNT: |
a4669ed8 | 934 | return autofs4_ask_umount(filp->f_path.mnt, p); |
1da177e4 LT |
935 | |
936 | /* return a single thing to expire */ | |
937 | case AUTOFS_IOC_EXPIRE: | |
a4669ed8 | 938 | return autofs4_expire_run(inode->i_sb,filp->f_path.mnt,sbi, p); |
1da177e4 LT |
939 | /* same as above, but can send multiple expires through pipe */ |
940 | case AUTOFS_IOC_EXPIRE_MULTI: | |
a4669ed8 | 941 | return autofs4_expire_multi(inode->i_sb,filp->f_path.mnt,sbi, p); |
1da177e4 LT |
942 | |
943 | default: | |
944 | return -ENOSYS; | |
945 | } | |
946 | } |