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7063fbf2 JB |
1 | /* -*- mode: c; c-basic-offset: 8; -*- |
2 | * vim: noexpandtab sw=8 ts=8 sts=0: | |
3 | * | |
4 | * dir.c - Operations for configfs directories. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public | |
8 | * License as published by the Free Software Foundation; either | |
9 | * version 2 of the License, or (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public | |
17 | * License along with this program; if not, write to the | |
18 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
19 | * Boston, MA 021110-1307, USA. | |
20 | * | |
21 | * Based on sysfs: | |
22 | * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel | |
23 | * | |
24 | * configfs Copyright (C) 2005 Oracle. All rights reserved. | |
25 | */ | |
26 | ||
27 | #undef DEBUG | |
28 | ||
29 | #include <linux/fs.h> | |
30 | #include <linux/mount.h> | |
31 | #include <linux/module.h> | |
32 | #include <linux/slab.h> | |
33 | ||
34 | #include <linux/configfs.h> | |
35 | #include "configfs_internal.h" | |
36 | ||
37 | DECLARE_RWSEM(configfs_rename_sem); | |
38 | ||
39 | static void configfs_d_iput(struct dentry * dentry, | |
40 | struct inode * inode) | |
41 | { | |
42 | struct configfs_dirent * sd = dentry->d_fsdata; | |
43 | ||
44 | if (sd) { | |
45 | BUG_ON(sd->s_dentry != dentry); | |
46 | sd->s_dentry = NULL; | |
47 | configfs_put(sd); | |
48 | } | |
49 | iput(inode); | |
50 | } | |
51 | ||
52 | /* | |
53 | * We _must_ delete our dentries on last dput, as the chain-to-parent | |
54 | * behavior is required to clear the parents of default_groups. | |
55 | */ | |
56 | static int configfs_d_delete(struct dentry *dentry) | |
57 | { | |
58 | return 1; | |
59 | } | |
60 | ||
61 | static struct dentry_operations configfs_dentry_ops = { | |
62 | .d_iput = configfs_d_iput, | |
63 | /* simple_delete_dentry() isn't exported */ | |
64 | .d_delete = configfs_d_delete, | |
65 | }; | |
66 | ||
67 | /* | |
68 | * Allocates a new configfs_dirent and links it to the parent configfs_dirent | |
69 | */ | |
70 | static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent * parent_sd, | |
71 | void * element) | |
72 | { | |
73 | struct configfs_dirent * sd; | |
74 | ||
c3762229 | 75 | sd = kmem_cache_zalloc(configfs_dir_cachep, GFP_KERNEL); |
7063fbf2 JB |
76 | if (!sd) |
77 | return NULL; | |
78 | ||
7063fbf2 JB |
79 | atomic_set(&sd->s_count, 1); |
80 | INIT_LIST_HEAD(&sd->s_links); | |
81 | INIT_LIST_HEAD(&sd->s_children); | |
82 | list_add(&sd->s_sibling, &parent_sd->s_children); | |
83 | sd->s_element = element; | |
84 | ||
85 | return sd; | |
86 | } | |
87 | ||
b4c98f62 JB |
88 | /* |
89 | * | |
90 | * Return -EEXIST if there is already a configfs element with the same | |
91 | * name for the same parent. | |
92 | * | |
93 | * called with parent inode's i_mutex held | |
94 | */ | |
58d206c2 AB |
95 | static int configfs_dirent_exists(struct configfs_dirent *parent_sd, |
96 | const unsigned char *new) | |
b4c98f62 JB |
97 | { |
98 | struct configfs_dirent * sd; | |
99 | ||
100 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
101 | if (sd->s_element) { | |
102 | const unsigned char *existing = configfs_get_name(sd); | |
103 | if (strcmp(existing, new)) | |
104 | continue; | |
105 | else | |
106 | return -EEXIST; | |
107 | } | |
108 | } | |
109 | ||
110 | return 0; | |
111 | } | |
112 | ||
113 | ||
7063fbf2 JB |
114 | int configfs_make_dirent(struct configfs_dirent * parent_sd, |
115 | struct dentry * dentry, void * element, | |
116 | umode_t mode, int type) | |
117 | { | |
118 | struct configfs_dirent * sd; | |
119 | ||
120 | sd = configfs_new_dirent(parent_sd, element); | |
121 | if (!sd) | |
122 | return -ENOMEM; | |
123 | ||
124 | sd->s_mode = mode; | |
125 | sd->s_type = type; | |
126 | sd->s_dentry = dentry; | |
127 | if (dentry) { | |
128 | dentry->d_fsdata = configfs_get(sd); | |
129 | dentry->d_op = &configfs_dentry_ops; | |
130 | } | |
131 | ||
132 | return 0; | |
133 | } | |
134 | ||
135 | static int init_dir(struct inode * inode) | |
136 | { | |
137 | inode->i_op = &configfs_dir_inode_operations; | |
138 | inode->i_fop = &configfs_dir_operations; | |
139 | ||
140 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |
d8c76e6f | 141 | inc_nlink(inode); |
7063fbf2 JB |
142 | return 0; |
143 | } | |
144 | ||
145 | static int init_file(struct inode * inode) | |
146 | { | |
147 | inode->i_size = PAGE_SIZE; | |
148 | inode->i_fop = &configfs_file_operations; | |
149 | return 0; | |
150 | } | |
151 | ||
152 | static int init_symlink(struct inode * inode) | |
153 | { | |
154 | inode->i_op = &configfs_symlink_inode_operations; | |
155 | return 0; | |
156 | } | |
157 | ||
158 | static int create_dir(struct config_item * k, struct dentry * p, | |
159 | struct dentry * d) | |
160 | { | |
161 | int error; | |
162 | umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; | |
163 | ||
b4c98f62 JB |
164 | error = configfs_dirent_exists(p->d_fsdata, d->d_name.name); |
165 | if (!error) | |
166 | error = configfs_make_dirent(p->d_fsdata, d, k, mode, | |
167 | CONFIGFS_DIR); | |
7063fbf2 | 168 | if (!error) { |
3d0f89bb | 169 | error = configfs_create(d, mode, init_dir); |
7063fbf2 | 170 | if (!error) { |
d8c76e6f | 171 | inc_nlink(p->d_inode); |
7063fbf2 | 172 | (d)->d_op = &configfs_dentry_ops; |
3d0f89bb JB |
173 | } else { |
174 | struct configfs_dirent *sd = d->d_fsdata; | |
175 | if (sd) { | |
176 | list_del_init(&sd->s_sibling); | |
177 | configfs_put(sd); | |
178 | } | |
7063fbf2 JB |
179 | } |
180 | } | |
181 | return error; | |
182 | } | |
183 | ||
184 | ||
185 | /** | |
186 | * configfs_create_dir - create a directory for an config_item. | |
187 | * @item: config_itemwe're creating directory for. | |
188 | * @dentry: config_item's dentry. | |
189 | */ | |
190 | ||
191 | static int configfs_create_dir(struct config_item * item, struct dentry *dentry) | |
192 | { | |
193 | struct dentry * parent; | |
194 | int error = 0; | |
195 | ||
196 | BUG_ON(!item); | |
197 | ||
198 | if (item->ci_parent) | |
199 | parent = item->ci_parent->ci_dentry; | |
200 | else if (configfs_mount && configfs_mount->mnt_sb) | |
201 | parent = configfs_mount->mnt_sb->s_root; | |
202 | else | |
203 | return -EFAULT; | |
204 | ||
205 | error = create_dir(item,parent,dentry); | |
206 | if (!error) | |
207 | item->ci_dentry = dentry; | |
208 | return error; | |
209 | } | |
210 | ||
211 | int configfs_create_link(struct configfs_symlink *sl, | |
212 | struct dentry *parent, | |
213 | struct dentry *dentry) | |
214 | { | |
215 | int err = 0; | |
216 | umode_t mode = S_IFLNK | S_IRWXUGO; | |
217 | ||
3d0f89bb JB |
218 | err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode, |
219 | CONFIGFS_ITEM_LINK); | |
7063fbf2 | 220 | if (!err) { |
3d0f89bb | 221 | err = configfs_create(dentry, mode, init_symlink); |
7063fbf2 JB |
222 | if (!err) |
223 | dentry->d_op = &configfs_dentry_ops; | |
3d0f89bb JB |
224 | else { |
225 | struct configfs_dirent *sd = dentry->d_fsdata; | |
226 | if (sd) { | |
227 | list_del_init(&sd->s_sibling); | |
228 | configfs_put(sd); | |
229 | } | |
230 | } | |
7063fbf2 JB |
231 | } |
232 | return err; | |
233 | } | |
234 | ||
235 | static void remove_dir(struct dentry * d) | |
236 | { | |
237 | struct dentry * parent = dget(d->d_parent); | |
238 | struct configfs_dirent * sd; | |
239 | ||
240 | sd = d->d_fsdata; | |
e7515d06 | 241 | list_del_init(&sd->s_sibling); |
7063fbf2 JB |
242 | configfs_put(sd); |
243 | if (d->d_inode) | |
244 | simple_rmdir(parent->d_inode,d); | |
245 | ||
246 | pr_debug(" o %s removing done (%d)\n",d->d_name.name, | |
247 | atomic_read(&d->d_count)); | |
248 | ||
249 | dput(parent); | |
250 | } | |
251 | ||
252 | /** | |
253 | * configfs_remove_dir - remove an config_item's directory. | |
254 | * @item: config_item we're removing. | |
255 | * | |
256 | * The only thing special about this is that we remove any files in | |
257 | * the directory before we remove the directory, and we've inlined | |
258 | * what used to be configfs_rmdir() below, instead of calling separately. | |
259 | */ | |
260 | ||
261 | static void configfs_remove_dir(struct config_item * item) | |
262 | { | |
263 | struct dentry * dentry = dget(item->ci_dentry); | |
264 | ||
265 | if (!dentry) | |
266 | return; | |
267 | ||
268 | remove_dir(dentry); | |
269 | /** | |
270 | * Drop reference from dget() on entrance. | |
271 | */ | |
272 | dput(dentry); | |
273 | } | |
274 | ||
275 | ||
276 | /* attaches attribute's configfs_dirent to the dentry corresponding to the | |
277 | * attribute file | |
278 | */ | |
279 | static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry) | |
280 | { | |
281 | struct configfs_attribute * attr = sd->s_element; | |
282 | int error; | |
283 | ||
3d0f89bb JB |
284 | dentry->d_fsdata = configfs_get(sd); |
285 | sd->s_dentry = dentry; | |
7063fbf2 | 286 | error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG, init_file); |
3d0f89bb JB |
287 | if (error) { |
288 | configfs_put(sd); | |
7063fbf2 | 289 | return error; |
3d0f89bb | 290 | } |
7063fbf2 JB |
291 | |
292 | dentry->d_op = &configfs_dentry_ops; | |
7063fbf2 JB |
293 | d_rehash(dentry); |
294 | ||
295 | return 0; | |
296 | } | |
297 | ||
298 | static struct dentry * configfs_lookup(struct inode *dir, | |
299 | struct dentry *dentry, | |
300 | struct nameidata *nd) | |
301 | { | |
302 | struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata; | |
303 | struct configfs_dirent * sd; | |
304 | int found = 0; | |
305 | int err = 0; | |
306 | ||
307 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
308 | if (sd->s_type & CONFIGFS_NOT_PINNED) { | |
309 | const unsigned char * name = configfs_get_name(sd); | |
310 | ||
311 | if (strcmp(name, dentry->d_name.name)) | |
312 | continue; | |
313 | ||
314 | found = 1; | |
315 | err = configfs_attach_attr(sd, dentry); | |
316 | break; | |
317 | } | |
318 | } | |
319 | ||
320 | if (!found) { | |
321 | /* | |
322 | * If it doesn't exist and it isn't a NOT_PINNED item, | |
323 | * it must be negative. | |
324 | */ | |
325 | return simple_lookup(dir, dentry, nd); | |
326 | } | |
327 | ||
328 | return ERR_PTR(err); | |
329 | } | |
330 | ||
331 | /* | |
332 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are | |
1b1dcc1b | 333 | * attributes and are removed by rmdir(). We recurse, taking i_mutex |
7063fbf2 JB |
334 | * on all children that are candidates for default detach. If the |
335 | * result is clean, then configfs_detach_group() will handle dropping | |
1b1dcc1b | 336 | * i_mutex. If there is an error, the caller will clean up the i_mutex |
7063fbf2 JB |
337 | * holders via configfs_detach_rollback(). |
338 | */ | |
339 | static int configfs_detach_prep(struct dentry *dentry) | |
340 | { | |
341 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
342 | struct configfs_dirent *sd; | |
343 | int ret; | |
344 | ||
345 | ret = -EBUSY; | |
346 | if (!list_empty(&parent_sd->s_links)) | |
347 | goto out; | |
348 | ||
349 | ret = 0; | |
350 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
351 | if (sd->s_type & CONFIGFS_NOT_PINNED) | |
352 | continue; | |
353 | if (sd->s_type & CONFIGFS_USET_DEFAULT) { | |
1b1dcc1b JS |
354 | mutex_lock(&sd->s_dentry->d_inode->i_mutex); |
355 | /* Mark that we've taken i_mutex */ | |
7063fbf2 JB |
356 | sd->s_type |= CONFIGFS_USET_DROPPING; |
357 | ||
358 | ret = configfs_detach_prep(sd->s_dentry); | |
359 | if (!ret) | |
e7515d06 | 360 | continue; |
7063fbf2 JB |
361 | } else |
362 | ret = -ENOTEMPTY; | |
363 | ||
364 | break; | |
365 | } | |
366 | ||
367 | out: | |
368 | return ret; | |
369 | } | |
370 | ||
371 | /* | |
1b1dcc1b | 372 | * Walk the tree, dropping i_mutex wherever CONFIGFS_USET_DROPPING is |
7063fbf2 JB |
373 | * set. |
374 | */ | |
375 | static void configfs_detach_rollback(struct dentry *dentry) | |
376 | { | |
377 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
378 | struct configfs_dirent *sd; | |
379 | ||
380 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
381 | if (sd->s_type & CONFIGFS_USET_DEFAULT) { | |
382 | configfs_detach_rollback(sd->s_dentry); | |
383 | ||
384 | if (sd->s_type & CONFIGFS_USET_DROPPING) { | |
385 | sd->s_type &= ~CONFIGFS_USET_DROPPING; | |
1b1dcc1b | 386 | mutex_unlock(&sd->s_dentry->d_inode->i_mutex); |
7063fbf2 JB |
387 | } |
388 | } | |
389 | } | |
390 | } | |
391 | ||
392 | static void detach_attrs(struct config_item * item) | |
393 | { | |
394 | struct dentry * dentry = dget(item->ci_dentry); | |
395 | struct configfs_dirent * parent_sd; | |
396 | struct configfs_dirent * sd, * tmp; | |
397 | ||
398 | if (!dentry) | |
399 | return; | |
400 | ||
401 | pr_debug("configfs %s: dropping attrs for dir\n", | |
402 | dentry->d_name.name); | |
403 | ||
404 | parent_sd = dentry->d_fsdata; | |
405 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
406 | if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED)) | |
407 | continue; | |
408 | list_del_init(&sd->s_sibling); | |
409 | configfs_drop_dentry(sd, dentry); | |
410 | configfs_put(sd); | |
411 | } | |
412 | ||
413 | /** | |
414 | * Drop reference from dget() on entrance. | |
415 | */ | |
416 | dput(dentry); | |
417 | } | |
418 | ||
419 | static int populate_attrs(struct config_item *item) | |
420 | { | |
421 | struct config_item_type *t = item->ci_type; | |
422 | struct configfs_attribute *attr; | |
423 | int error = 0; | |
424 | int i; | |
425 | ||
426 | if (!t) | |
427 | return -EINVAL; | |
428 | if (t->ct_attrs) { | |
429 | for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) { | |
430 | if ((error = configfs_create_file(item, attr))) | |
431 | break; | |
432 | } | |
433 | } | |
434 | ||
435 | if (error) | |
436 | detach_attrs(item); | |
437 | ||
438 | return error; | |
439 | } | |
440 | ||
441 | static int configfs_attach_group(struct config_item *parent_item, | |
442 | struct config_item *item, | |
443 | struct dentry *dentry); | |
444 | static void configfs_detach_group(struct config_item *item); | |
445 | ||
446 | static void detach_groups(struct config_group *group) | |
447 | { | |
448 | struct dentry * dentry = dget(group->cg_item.ci_dentry); | |
449 | struct dentry *child; | |
450 | struct configfs_dirent *parent_sd; | |
451 | struct configfs_dirent *sd, *tmp; | |
452 | ||
453 | if (!dentry) | |
454 | return; | |
455 | ||
456 | parent_sd = dentry->d_fsdata; | |
457 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
458 | if (!sd->s_element || | |
459 | !(sd->s_type & CONFIGFS_USET_DEFAULT)) | |
460 | continue; | |
461 | ||
462 | child = sd->s_dentry; | |
463 | ||
464 | configfs_detach_group(sd->s_element); | |
465 | child->d_inode->i_flags |= S_DEAD; | |
466 | ||
467 | /* | |
468 | * From rmdir/unregister, a configfs_detach_prep() pass | |
1b1dcc1b | 469 | * has taken our i_mutex for us. Drop it. |
7063fbf2 JB |
470 | * From mkdir/register cleanup, there is no sem held. |
471 | */ | |
472 | if (sd->s_type & CONFIGFS_USET_DROPPING) | |
1b1dcc1b | 473 | mutex_unlock(&child->d_inode->i_mutex); |
7063fbf2 JB |
474 | |
475 | d_delete(child); | |
476 | dput(child); | |
477 | } | |
478 | ||
479 | /** | |
480 | * Drop reference from dget() on entrance. | |
481 | */ | |
482 | dput(dentry); | |
483 | } | |
484 | ||
485 | /* | |
486 | * This fakes mkdir(2) on a default_groups[] entry. It | |
487 | * creates a dentry, attachs it, and then does fixup | |
488 | * on the sd->s_type. | |
489 | * | |
490 | * We could, perhaps, tweak our parent's ->mkdir for a minute and | |
491 | * try using vfs_mkdir. Just a thought. | |
492 | */ | |
493 | static int create_default_group(struct config_group *parent_group, | |
494 | struct config_group *group) | |
495 | { | |
496 | int ret; | |
497 | struct qstr name; | |
498 | struct configfs_dirent *sd; | |
499 | /* We trust the caller holds a reference to parent */ | |
500 | struct dentry *child, *parent = parent_group->cg_item.ci_dentry; | |
501 | ||
502 | if (!group->cg_item.ci_name) | |
503 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
504 | name.name = group->cg_item.ci_name; | |
505 | name.len = strlen(name.name); | |
506 | name.hash = full_name_hash(name.name, name.len); | |
507 | ||
508 | ret = -ENOMEM; | |
509 | child = d_alloc(parent, &name); | |
510 | if (child) { | |
511 | d_add(child, NULL); | |
512 | ||
513 | ret = configfs_attach_group(&parent_group->cg_item, | |
514 | &group->cg_item, child); | |
515 | if (!ret) { | |
516 | sd = child->d_fsdata; | |
517 | sd->s_type |= CONFIGFS_USET_DEFAULT; | |
518 | } else { | |
519 | d_delete(child); | |
520 | dput(child); | |
521 | } | |
522 | } | |
523 | ||
524 | return ret; | |
525 | } | |
526 | ||
527 | static int populate_groups(struct config_group *group) | |
528 | { | |
529 | struct config_group *new_group; | |
530 | struct dentry *dentry = group->cg_item.ci_dentry; | |
531 | int ret = 0; | |
532 | int i; | |
533 | ||
cbca692c | 534 | if (group->default_groups) { |
eed7a0db JB |
535 | /* |
536 | * FYI, we're faking mkdir here | |
7063fbf2 JB |
537 | * I'm not sure we need this semaphore, as we're called |
538 | * from our parent's mkdir. That holds our parent's | |
1b1dcc1b | 539 | * i_mutex, so afaik lookup cannot continue through our |
7063fbf2 | 540 | * parent to find us, let alone mess with our tree. |
1b1dcc1b | 541 | * That said, taking our i_mutex is closer to mkdir |
eed7a0db JB |
542 | * emulation, and shouldn't hurt. |
543 | */ | |
1b1dcc1b | 544 | mutex_lock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
545 | |
546 | for (i = 0; group->default_groups[i]; i++) { | |
547 | new_group = group->default_groups[i]; | |
548 | ||
549 | ret = create_default_group(group, new_group); | |
550 | if (ret) | |
551 | break; | |
552 | } | |
553 | ||
1b1dcc1b | 554 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
555 | } |
556 | ||
557 | if (ret) | |
558 | detach_groups(group); | |
559 | ||
560 | return ret; | |
561 | } | |
562 | ||
563 | /* | |
564 | * All of link_obj/unlink_obj/link_group/unlink_group require that | |
565 | * subsys->su_sem is held. | |
566 | */ | |
567 | ||
568 | static void unlink_obj(struct config_item *item) | |
569 | { | |
570 | struct config_group *group; | |
571 | ||
572 | group = item->ci_group; | |
573 | if (group) { | |
574 | list_del_init(&item->ci_entry); | |
575 | ||
576 | item->ci_group = NULL; | |
577 | item->ci_parent = NULL; | |
eed7a0db JB |
578 | |
579 | /* Drop the reference for ci_entry */ | |
7063fbf2 JB |
580 | config_item_put(item); |
581 | ||
eed7a0db | 582 | /* Drop the reference for ci_parent */ |
7063fbf2 JB |
583 | config_group_put(group); |
584 | } | |
585 | } | |
586 | ||
587 | static void link_obj(struct config_item *parent_item, struct config_item *item) | |
588 | { | |
eed7a0db JB |
589 | /* |
590 | * Parent seems redundant with group, but it makes certain | |
591 | * traversals much nicer. | |
592 | */ | |
7063fbf2 | 593 | item->ci_parent = parent_item; |
eed7a0db JB |
594 | |
595 | /* | |
596 | * We hold a reference on the parent for the child's ci_parent | |
597 | * link. | |
598 | */ | |
7063fbf2 JB |
599 | item->ci_group = config_group_get(to_config_group(parent_item)); |
600 | list_add_tail(&item->ci_entry, &item->ci_group->cg_children); | |
601 | ||
eed7a0db JB |
602 | /* |
603 | * We hold a reference on the child for ci_entry on the parent's | |
604 | * cg_children | |
605 | */ | |
7063fbf2 JB |
606 | config_item_get(item); |
607 | } | |
608 | ||
609 | static void unlink_group(struct config_group *group) | |
610 | { | |
611 | int i; | |
612 | struct config_group *new_group; | |
613 | ||
614 | if (group->default_groups) { | |
615 | for (i = 0; group->default_groups[i]; i++) { | |
616 | new_group = group->default_groups[i]; | |
617 | unlink_group(new_group); | |
618 | } | |
619 | } | |
620 | ||
621 | group->cg_subsys = NULL; | |
622 | unlink_obj(&group->cg_item); | |
623 | } | |
624 | ||
625 | static void link_group(struct config_group *parent_group, struct config_group *group) | |
626 | { | |
627 | int i; | |
628 | struct config_group *new_group; | |
629 | struct configfs_subsystem *subsys = NULL; /* gcc is a turd */ | |
630 | ||
631 | link_obj(&parent_group->cg_item, &group->cg_item); | |
632 | ||
633 | if (parent_group->cg_subsys) | |
634 | subsys = parent_group->cg_subsys; | |
635 | else if (configfs_is_root(&parent_group->cg_item)) | |
636 | subsys = to_configfs_subsystem(group); | |
637 | else | |
638 | BUG(); | |
639 | group->cg_subsys = subsys; | |
640 | ||
641 | if (group->default_groups) { | |
642 | for (i = 0; group->default_groups[i]; i++) { | |
643 | new_group = group->default_groups[i]; | |
644 | link_group(group, new_group); | |
645 | } | |
646 | } | |
647 | } | |
648 | ||
649 | /* | |
650 | * The goal is that configfs_attach_item() (and | |
651 | * configfs_attach_group()) can be called from either the VFS or this | |
652 | * module. That is, they assume that the items have been created, | |
653 | * the dentry allocated, and the dcache is all ready to go. | |
654 | * | |
655 | * If they fail, they must clean up after themselves as if they | |
656 | * had never been called. The caller (VFS or local function) will | |
657 | * handle cleaning up the dcache bits. | |
658 | * | |
659 | * configfs_detach_group() and configfs_detach_item() behave similarly on | |
660 | * the way out. They assume that the proper semaphores are held, they | |
661 | * clean up the configfs items, and they expect their callers will | |
662 | * handle the dcache bits. | |
663 | */ | |
664 | static int configfs_attach_item(struct config_item *parent_item, | |
665 | struct config_item *item, | |
666 | struct dentry *dentry) | |
667 | { | |
668 | int ret; | |
669 | ||
670 | ret = configfs_create_dir(item, dentry); | |
671 | if (!ret) { | |
672 | ret = populate_attrs(item); | |
673 | if (ret) { | |
674 | configfs_remove_dir(item); | |
675 | d_delete(dentry); | |
676 | } | |
677 | } | |
678 | ||
679 | return ret; | |
680 | } | |
681 | ||
682 | static void configfs_detach_item(struct config_item *item) | |
683 | { | |
684 | detach_attrs(item); | |
685 | configfs_remove_dir(item); | |
686 | } | |
687 | ||
688 | static int configfs_attach_group(struct config_item *parent_item, | |
689 | struct config_item *item, | |
690 | struct dentry *dentry) | |
691 | { | |
692 | int ret; | |
693 | struct configfs_dirent *sd; | |
694 | ||
695 | ret = configfs_attach_item(parent_item, item, dentry); | |
696 | if (!ret) { | |
697 | sd = dentry->d_fsdata; | |
698 | sd->s_type |= CONFIGFS_USET_DIR; | |
699 | ||
700 | ret = populate_groups(to_config_group(item)); | |
701 | if (ret) { | |
702 | configfs_detach_item(item); | |
703 | d_delete(dentry); | |
704 | } | |
705 | } | |
706 | ||
707 | return ret; | |
708 | } | |
709 | ||
710 | static void configfs_detach_group(struct config_item *item) | |
711 | { | |
712 | detach_groups(to_config_group(item)); | |
713 | configfs_detach_item(item); | |
714 | } | |
715 | ||
716 | /* | |
717 | * Drop the initial reference from make_item()/make_group() | |
718 | * This function assumes that reference is held on item | |
719 | * and that item holds a valid reference to the parent. Also, it | |
720 | * assumes the caller has validated ci_type. | |
721 | */ | |
722 | static void client_drop_item(struct config_item *parent_item, | |
723 | struct config_item *item) | |
724 | { | |
725 | struct config_item_type *type; | |
726 | ||
727 | type = parent_item->ci_type; | |
728 | BUG_ON(!type); | |
729 | ||
eed7a0db JB |
730 | /* |
731 | * If ->drop_item() exists, it is responsible for the | |
732 | * config_item_put(). | |
733 | */ | |
7063fbf2 JB |
734 | if (type->ct_group_ops && type->ct_group_ops->drop_item) |
735 | type->ct_group_ops->drop_item(to_config_group(parent_item), | |
736 | item); | |
737 | else | |
738 | config_item_put(item); | |
739 | } | |
740 | ||
741 | ||
742 | static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
743 | { | |
eed7a0db | 744 | int ret, module_got = 0; |
7063fbf2 JB |
745 | struct config_group *group; |
746 | struct config_item *item; | |
747 | struct config_item *parent_item; | |
748 | struct configfs_subsystem *subsys; | |
749 | struct configfs_dirent *sd; | |
750 | struct config_item_type *type; | |
eed7a0db | 751 | struct module *owner = NULL; |
7063fbf2 JB |
752 | char *name; |
753 | ||
84efad1a JB |
754 | if (dentry->d_parent == configfs_sb->s_root) { |
755 | ret = -EPERM; | |
756 | goto out; | |
757 | } | |
7063fbf2 JB |
758 | |
759 | sd = dentry->d_parent->d_fsdata; | |
84efad1a JB |
760 | if (!(sd->s_type & CONFIGFS_USET_DIR)) { |
761 | ret = -EPERM; | |
762 | goto out; | |
763 | } | |
7063fbf2 | 764 | |
84efad1a | 765 | /* Get a working ref for the duration of this function */ |
7063fbf2 JB |
766 | parent_item = configfs_get_config_item(dentry->d_parent); |
767 | type = parent_item->ci_type; | |
768 | subsys = to_config_group(parent_item)->cg_subsys; | |
769 | BUG_ON(!subsys); | |
770 | ||
771 | if (!type || !type->ct_group_ops || | |
772 | (!type->ct_group_ops->make_group && | |
773 | !type->ct_group_ops->make_item)) { | |
84efad1a JB |
774 | ret = -EPERM; /* Lack-of-mkdir returns -EPERM */ |
775 | goto out_put; | |
7063fbf2 JB |
776 | } |
777 | ||
778 | name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL); | |
779 | if (!name) { | |
84efad1a JB |
780 | ret = -ENOMEM; |
781 | goto out_put; | |
7063fbf2 | 782 | } |
84efad1a | 783 | |
7063fbf2 JB |
784 | snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name); |
785 | ||
786 | down(&subsys->su_sem); | |
787 | group = NULL; | |
788 | item = NULL; | |
789 | if (type->ct_group_ops->make_group) { | |
790 | group = type->ct_group_ops->make_group(to_config_group(parent_item), name); | |
791 | if (group) { | |
792 | link_group(to_config_group(parent_item), group); | |
793 | item = &group->cg_item; | |
794 | } | |
795 | } else { | |
796 | item = type->ct_group_ops->make_item(to_config_group(parent_item), name); | |
797 | if (item) | |
798 | link_obj(parent_item, item); | |
799 | } | |
800 | up(&subsys->su_sem); | |
801 | ||
802 | kfree(name); | |
803 | if (!item) { | |
eed7a0db JB |
804 | /* |
805 | * If item == NULL, then link_obj() was never called. | |
806 | * There are no extra references to clean up. | |
807 | */ | |
84efad1a JB |
808 | ret = -ENOMEM; |
809 | goto out_put; | |
7063fbf2 JB |
810 | } |
811 | ||
eed7a0db JB |
812 | /* |
813 | * link_obj() has been called (via link_group() for groups). | |
814 | * From here on out, errors must clean that up. | |
815 | */ | |
816 | ||
7063fbf2 | 817 | type = item->ci_type; |
eed7a0db JB |
818 | if (!type) { |
819 | ret = -EINVAL; | |
820 | goto out_unlink; | |
821 | } | |
7063fbf2 | 822 | |
eed7a0db JB |
823 | owner = type->ct_owner; |
824 | if (!try_module_get(owner)) { | |
825 | ret = -EINVAL; | |
826 | goto out_unlink; | |
827 | } | |
7063fbf2 | 828 | |
eed7a0db JB |
829 | /* |
830 | * I hate doing it this way, but if there is | |
831 | * an error, module_put() probably should | |
832 | * happen after any cleanup. | |
833 | */ | |
834 | module_got = 1; | |
835 | ||
836 | if (group) | |
837 | ret = configfs_attach_group(parent_item, item, dentry); | |
838 | else | |
839 | ret = configfs_attach_item(parent_item, item, dentry); | |
840 | ||
841 | out_unlink: | |
842 | if (ret) { | |
843 | /* Tear down everything we built up */ | |
844 | down(&subsys->su_sem); | |
845 | if (group) | |
846 | unlink_group(group); | |
847 | else | |
848 | unlink_obj(item); | |
849 | client_drop_item(parent_item, item); | |
850 | up(&subsys->su_sem); | |
851 | ||
852 | if (module_got) | |
853 | module_put(owner); | |
7063fbf2 JB |
854 | } |
855 | ||
84efad1a JB |
856 | out_put: |
857 | /* | |
eed7a0db JB |
858 | * link_obj()/link_group() took a reference from child->parent, |
859 | * so the parent is safely pinned. We can drop our working | |
860 | * reference. | |
84efad1a JB |
861 | */ |
862 | config_item_put(parent_item); | |
863 | ||
864 | out: | |
7063fbf2 JB |
865 | return ret; |
866 | } | |
867 | ||
868 | static int configfs_rmdir(struct inode *dir, struct dentry *dentry) | |
869 | { | |
870 | struct config_item *parent_item; | |
871 | struct config_item *item; | |
872 | struct configfs_subsystem *subsys; | |
873 | struct configfs_dirent *sd; | |
874 | struct module *owner = NULL; | |
875 | int ret; | |
876 | ||
877 | if (dentry->d_parent == configfs_sb->s_root) | |
878 | return -EPERM; | |
879 | ||
880 | sd = dentry->d_fsdata; | |
881 | if (sd->s_type & CONFIGFS_USET_DEFAULT) | |
882 | return -EPERM; | |
883 | ||
84efad1a | 884 | /* Get a working ref until we have the child */ |
7063fbf2 JB |
885 | parent_item = configfs_get_config_item(dentry->d_parent); |
886 | subsys = to_config_group(parent_item)->cg_subsys; | |
887 | BUG_ON(!subsys); | |
888 | ||
889 | if (!parent_item->ci_type) { | |
890 | config_item_put(parent_item); | |
891 | return -EINVAL; | |
892 | } | |
893 | ||
894 | ret = configfs_detach_prep(dentry); | |
895 | if (ret) { | |
896 | configfs_detach_rollback(dentry); | |
897 | config_item_put(parent_item); | |
898 | return ret; | |
899 | } | |
900 | ||
84efad1a | 901 | /* Get a working ref for the duration of this function */ |
7063fbf2 JB |
902 | item = configfs_get_config_item(dentry); |
903 | ||
904 | /* Drop reference from above, item already holds one. */ | |
905 | config_item_put(parent_item); | |
906 | ||
907 | if (item->ci_type) | |
908 | owner = item->ci_type->ct_owner; | |
909 | ||
910 | if (sd->s_type & CONFIGFS_USET_DIR) { | |
911 | configfs_detach_group(item); | |
912 | ||
913 | down(&subsys->su_sem); | |
914 | unlink_group(to_config_group(item)); | |
915 | } else { | |
916 | configfs_detach_item(item); | |
917 | ||
918 | down(&subsys->su_sem); | |
919 | unlink_obj(item); | |
920 | } | |
921 | ||
922 | client_drop_item(parent_item, item); | |
923 | up(&subsys->su_sem); | |
924 | ||
925 | /* Drop our reference from above */ | |
926 | config_item_put(item); | |
927 | ||
928 | module_put(owner); | |
929 | ||
930 | return 0; | |
931 | } | |
932 | ||
933 | struct inode_operations configfs_dir_inode_operations = { | |
934 | .mkdir = configfs_mkdir, | |
935 | .rmdir = configfs_rmdir, | |
936 | .symlink = configfs_symlink, | |
937 | .unlink = configfs_unlink, | |
938 | .lookup = configfs_lookup, | |
3d0f89bb | 939 | .setattr = configfs_setattr, |
7063fbf2 JB |
940 | }; |
941 | ||
942 | #if 0 | |
943 | int configfs_rename_dir(struct config_item * item, const char *new_name) | |
944 | { | |
945 | int error = 0; | |
946 | struct dentry * new_dentry, * parent; | |
947 | ||
948 | if (!strcmp(config_item_name(item), new_name)) | |
949 | return -EINVAL; | |
950 | ||
951 | if (!item->parent) | |
952 | return -EINVAL; | |
953 | ||
954 | down_write(&configfs_rename_sem); | |
955 | parent = item->parent->dentry; | |
956 | ||
1b1dcc1b | 957 | mutex_lock(&parent->d_inode->i_mutex); |
7063fbf2 JB |
958 | |
959 | new_dentry = lookup_one_len(new_name, parent, strlen(new_name)); | |
960 | if (!IS_ERR(new_dentry)) { | |
e7515d06 | 961 | if (!new_dentry->d_inode) { |
7063fbf2 JB |
962 | error = config_item_set_name(item, "%s", new_name); |
963 | if (!error) { | |
964 | d_add(new_dentry, NULL); | |
965 | d_move(item->dentry, new_dentry); | |
966 | } | |
967 | else | |
968 | d_delete(new_dentry); | |
969 | } else | |
970 | error = -EEXIST; | |
971 | dput(new_dentry); | |
972 | } | |
1b1dcc1b | 973 | mutex_unlock(&parent->d_inode->i_mutex); |
7063fbf2 JB |
974 | up_write(&configfs_rename_sem); |
975 | ||
976 | return error; | |
977 | } | |
978 | #endif | |
979 | ||
980 | static int configfs_dir_open(struct inode *inode, struct file *file) | |
981 | { | |
867fa491 | 982 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 JB |
983 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
984 | ||
1b1dcc1b | 985 | mutex_lock(&dentry->d_inode->i_mutex); |
7063fbf2 | 986 | file->private_data = configfs_new_dirent(parent_sd, NULL); |
1b1dcc1b | 987 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
988 | |
989 | return file->private_data ? 0 : -ENOMEM; | |
990 | ||
991 | } | |
992 | ||
993 | static int configfs_dir_close(struct inode *inode, struct file *file) | |
994 | { | |
867fa491 | 995 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 JB |
996 | struct configfs_dirent * cursor = file->private_data; |
997 | ||
1b1dcc1b | 998 | mutex_lock(&dentry->d_inode->i_mutex); |
7063fbf2 | 999 | list_del_init(&cursor->s_sibling); |
1b1dcc1b | 1000 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1001 | |
1002 | release_configfs_dirent(cursor); | |
1003 | ||
1004 | return 0; | |
1005 | } | |
1006 | ||
1007 | /* Relationship between s_mode and the DT_xxx types */ | |
1008 | static inline unsigned char dt_type(struct configfs_dirent *sd) | |
1009 | { | |
1010 | return (sd->s_mode >> 12) & 15; | |
1011 | } | |
1012 | ||
1013 | static int configfs_readdir(struct file * filp, void * dirent, filldir_t filldir) | |
1014 | { | |
867fa491 | 1015 | struct dentry *dentry = filp->f_path.dentry; |
7063fbf2 JB |
1016 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
1017 | struct configfs_dirent *cursor = filp->private_data; | |
1018 | struct list_head *p, *q = &cursor->s_sibling; | |
1019 | ino_t ino; | |
1020 | int i = filp->f_pos; | |
1021 | ||
1022 | switch (i) { | |
1023 | case 0: | |
1024 | ino = dentry->d_inode->i_ino; | |
1025 | if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) | |
1026 | break; | |
1027 | filp->f_pos++; | |
1028 | i++; | |
1029 | /* fallthrough */ | |
1030 | case 1: | |
1031 | ino = parent_ino(dentry); | |
1032 | if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) | |
1033 | break; | |
1034 | filp->f_pos++; | |
1035 | i++; | |
1036 | /* fallthrough */ | |
1037 | default: | |
1038 | if (filp->f_pos == 2) { | |
f116629d | 1039 | list_move(q, &parent_sd->s_children); |
7063fbf2 JB |
1040 | } |
1041 | for (p=q->next; p!= &parent_sd->s_children; p=p->next) { | |
1042 | struct configfs_dirent *next; | |
1043 | const char * name; | |
1044 | int len; | |
1045 | ||
1046 | next = list_entry(p, struct configfs_dirent, | |
1047 | s_sibling); | |
1048 | if (!next->s_element) | |
1049 | continue; | |
1050 | ||
1051 | name = configfs_get_name(next); | |
1052 | len = strlen(name); | |
1053 | if (next->s_dentry) | |
1054 | ino = next->s_dentry->d_inode->i_ino; | |
1055 | else | |
1056 | ino = iunique(configfs_sb, 2); | |
1057 | ||
1058 | if (filldir(dirent, name, len, filp->f_pos, ino, | |
1059 | dt_type(next)) < 0) | |
1060 | return 0; | |
1061 | ||
f116629d | 1062 | list_move(q, p); |
7063fbf2 JB |
1063 | p = q; |
1064 | filp->f_pos++; | |
1065 | } | |
1066 | } | |
1067 | return 0; | |
1068 | } | |
1069 | ||
1070 | static loff_t configfs_dir_lseek(struct file * file, loff_t offset, int origin) | |
1071 | { | |
867fa491 | 1072 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 | 1073 | |
1b1dcc1b | 1074 | mutex_lock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1075 | switch (origin) { |
1076 | case 1: | |
1077 | offset += file->f_pos; | |
1078 | case 0: | |
1079 | if (offset >= 0) | |
1080 | break; | |
1081 | default: | |
867fa491 | 1082 | mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); |
7063fbf2 JB |
1083 | return -EINVAL; |
1084 | } | |
1085 | if (offset != file->f_pos) { | |
1086 | file->f_pos = offset; | |
1087 | if (file->f_pos >= 2) { | |
1088 | struct configfs_dirent *sd = dentry->d_fsdata; | |
1089 | struct configfs_dirent *cursor = file->private_data; | |
1090 | struct list_head *p; | |
1091 | loff_t n = file->f_pos - 2; | |
1092 | ||
1093 | list_del(&cursor->s_sibling); | |
1094 | p = sd->s_children.next; | |
1095 | while (n && p != &sd->s_children) { | |
1096 | struct configfs_dirent *next; | |
1097 | next = list_entry(p, struct configfs_dirent, | |
1098 | s_sibling); | |
1099 | if (next->s_element) | |
1100 | n--; | |
1101 | p = p->next; | |
1102 | } | |
1103 | list_add_tail(&cursor->s_sibling, p); | |
1104 | } | |
1105 | } | |
1b1dcc1b | 1106 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1107 | return offset; |
1108 | } | |
1109 | ||
4b6f5d20 | 1110 | const struct file_operations configfs_dir_operations = { |
7063fbf2 JB |
1111 | .open = configfs_dir_open, |
1112 | .release = configfs_dir_close, | |
1113 | .llseek = configfs_dir_lseek, | |
1114 | .read = generic_read_dir, | |
1115 | .readdir = configfs_readdir, | |
1116 | }; | |
1117 | ||
1118 | int configfs_register_subsystem(struct configfs_subsystem *subsys) | |
1119 | { | |
1120 | int err; | |
1121 | struct config_group *group = &subsys->su_group; | |
1122 | struct qstr name; | |
1123 | struct dentry *dentry; | |
1124 | struct configfs_dirent *sd; | |
1125 | ||
1126 | err = configfs_pin_fs(); | |
1127 | if (err) | |
1128 | return err; | |
1129 | ||
1130 | if (!group->cg_item.ci_name) | |
1131 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
1132 | ||
1133 | sd = configfs_sb->s_root->d_fsdata; | |
1134 | link_group(to_config_group(sd->s_element), group); | |
1135 | ||
1b1dcc1b | 1136 | mutex_lock(&configfs_sb->s_root->d_inode->i_mutex); |
7063fbf2 JB |
1137 | |
1138 | name.name = group->cg_item.ci_name; | |
1139 | name.len = strlen(name.name); | |
1140 | name.hash = full_name_hash(name.name, name.len); | |
1141 | ||
1142 | err = -ENOMEM; | |
1143 | dentry = d_alloc(configfs_sb->s_root, &name); | |
1144 | if (!dentry) | |
1145 | goto out_release; | |
1146 | ||
1147 | d_add(dentry, NULL); | |
1148 | ||
1149 | err = configfs_attach_group(sd->s_element, &group->cg_item, | |
1150 | dentry); | |
1151 | if (!err) | |
1152 | dentry = NULL; | |
1153 | else | |
1154 | d_delete(dentry); | |
1155 | ||
1b1dcc1b | 1156 | mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex); |
7063fbf2 JB |
1157 | |
1158 | if (dentry) { | |
1159 | dput(dentry); | |
1160 | out_release: | |
1161 | unlink_group(group); | |
1162 | configfs_release_fs(); | |
1163 | } | |
1164 | ||
1165 | return err; | |
1166 | } | |
1167 | ||
1168 | void configfs_unregister_subsystem(struct configfs_subsystem *subsys) | |
1169 | { | |
1170 | struct config_group *group = &subsys->su_group; | |
1171 | struct dentry *dentry = group->cg_item.ci_dentry; | |
1172 | ||
1173 | if (dentry->d_parent != configfs_sb->s_root) { | |
1174 | printk(KERN_ERR "configfs: Tried to unregister non-subsystem!\n"); | |
1175 | return; | |
1176 | } | |
1177 | ||
55ed1602 MF |
1178 | mutex_lock_nested(&configfs_sb->s_root->d_inode->i_mutex, |
1179 | I_MUTEX_PARENT); | |
1180 | mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); | |
7063fbf2 JB |
1181 | if (configfs_detach_prep(dentry)) { |
1182 | printk(KERN_ERR "configfs: Tried to unregister non-empty subsystem!\n"); | |
1183 | } | |
1184 | configfs_detach_group(&group->cg_item); | |
1185 | dentry->d_inode->i_flags |= S_DEAD; | |
1b1dcc1b | 1186 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1187 | |
1188 | d_delete(dentry); | |
1189 | ||
1b1dcc1b | 1190 | mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex); |
7063fbf2 JB |
1191 | |
1192 | dput(dentry); | |
1193 | ||
1194 | unlink_group(group); | |
1195 | configfs_release_fs(); | |
1196 | } | |
1197 | ||
1198 | EXPORT_SYMBOL(configfs_register_subsystem); | |
1199 | EXPORT_SYMBOL(configfs_unregister_subsystem); |