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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 | ||
3d0f89bb | 75 | sd = kmem_cache_alloc(configfs_dir_cachep, GFP_KERNEL); |
7063fbf2 JB |
76 | if (!sd) |
77 | return NULL; | |
78 | ||
79 | memset(sd, 0, sizeof(*sd)); | |
80 | atomic_set(&sd->s_count, 1); | |
81 | INIT_LIST_HEAD(&sd->s_links); | |
82 | INIT_LIST_HEAD(&sd->s_children); | |
83 | list_add(&sd->s_sibling, &parent_sd->s_children); | |
84 | sd->s_element = element; | |
85 | ||
86 | return sd; | |
87 | } | |
88 | ||
b4c98f62 JB |
89 | /* |
90 | * | |
91 | * Return -EEXIST if there is already a configfs element with the same | |
92 | * name for the same parent. | |
93 | * | |
94 | * called with parent inode's i_mutex held | |
95 | */ | |
58d206c2 AB |
96 | static int configfs_dirent_exists(struct configfs_dirent *parent_sd, |
97 | const unsigned char *new) | |
b4c98f62 JB |
98 | { |
99 | struct configfs_dirent * sd; | |
100 | ||
101 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
102 | if (sd->s_element) { | |
103 | const unsigned char *existing = configfs_get_name(sd); | |
104 | if (strcmp(existing, new)) | |
105 | continue; | |
106 | else | |
107 | return -EEXIST; | |
108 | } | |
109 | } | |
110 | ||
111 | return 0; | |
112 | } | |
113 | ||
114 | ||
7063fbf2 JB |
115 | int configfs_make_dirent(struct configfs_dirent * parent_sd, |
116 | struct dentry * dentry, void * element, | |
117 | umode_t mode, int type) | |
118 | { | |
119 | struct configfs_dirent * sd; | |
120 | ||
121 | sd = configfs_new_dirent(parent_sd, element); | |
122 | if (!sd) | |
123 | return -ENOMEM; | |
124 | ||
125 | sd->s_mode = mode; | |
126 | sd->s_type = type; | |
127 | sd->s_dentry = dentry; | |
128 | if (dentry) { | |
129 | dentry->d_fsdata = configfs_get(sd); | |
130 | dentry->d_op = &configfs_dentry_ops; | |
131 | } | |
132 | ||
133 | return 0; | |
134 | } | |
135 | ||
136 | static int init_dir(struct inode * inode) | |
137 | { | |
138 | inode->i_op = &configfs_dir_inode_operations; | |
139 | inode->i_fop = &configfs_dir_operations; | |
140 | ||
141 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |
d8c76e6f | 142 | inc_nlink(inode); |
7063fbf2 JB |
143 | return 0; |
144 | } | |
145 | ||
146 | static int init_file(struct inode * inode) | |
147 | { | |
148 | inode->i_size = PAGE_SIZE; | |
149 | inode->i_fop = &configfs_file_operations; | |
150 | return 0; | |
151 | } | |
152 | ||
153 | static int init_symlink(struct inode * inode) | |
154 | { | |
155 | inode->i_op = &configfs_symlink_inode_operations; | |
156 | return 0; | |
157 | } | |
158 | ||
159 | static int create_dir(struct config_item * k, struct dentry * p, | |
160 | struct dentry * d) | |
161 | { | |
162 | int error; | |
163 | umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; | |
164 | ||
b4c98f62 JB |
165 | error = configfs_dirent_exists(p->d_fsdata, d->d_name.name); |
166 | if (!error) | |
167 | error = configfs_make_dirent(p->d_fsdata, d, k, mode, | |
168 | CONFIGFS_DIR); | |
7063fbf2 | 169 | if (!error) { |
3d0f89bb | 170 | error = configfs_create(d, mode, init_dir); |
7063fbf2 | 171 | if (!error) { |
d8c76e6f | 172 | inc_nlink(p->d_inode); |
7063fbf2 | 173 | (d)->d_op = &configfs_dentry_ops; |
3d0f89bb JB |
174 | } else { |
175 | struct configfs_dirent *sd = d->d_fsdata; | |
176 | if (sd) { | |
177 | list_del_init(&sd->s_sibling); | |
178 | configfs_put(sd); | |
179 | } | |
7063fbf2 JB |
180 | } |
181 | } | |
182 | return error; | |
183 | } | |
184 | ||
185 | ||
186 | /** | |
187 | * configfs_create_dir - create a directory for an config_item. | |
188 | * @item: config_itemwe're creating directory for. | |
189 | * @dentry: config_item's dentry. | |
190 | */ | |
191 | ||
192 | static int configfs_create_dir(struct config_item * item, struct dentry *dentry) | |
193 | { | |
194 | struct dentry * parent; | |
195 | int error = 0; | |
196 | ||
197 | BUG_ON(!item); | |
198 | ||
199 | if (item->ci_parent) | |
200 | parent = item->ci_parent->ci_dentry; | |
201 | else if (configfs_mount && configfs_mount->mnt_sb) | |
202 | parent = configfs_mount->mnt_sb->s_root; | |
203 | else | |
204 | return -EFAULT; | |
205 | ||
206 | error = create_dir(item,parent,dentry); | |
207 | if (!error) | |
208 | item->ci_dentry = dentry; | |
209 | return error; | |
210 | } | |
211 | ||
212 | int configfs_create_link(struct configfs_symlink *sl, | |
213 | struct dentry *parent, | |
214 | struct dentry *dentry) | |
215 | { | |
216 | int err = 0; | |
217 | umode_t mode = S_IFLNK | S_IRWXUGO; | |
218 | ||
3d0f89bb JB |
219 | err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode, |
220 | CONFIGFS_ITEM_LINK); | |
7063fbf2 | 221 | if (!err) { |
3d0f89bb | 222 | err = configfs_create(dentry, mode, init_symlink); |
7063fbf2 JB |
223 | if (!err) |
224 | dentry->d_op = &configfs_dentry_ops; | |
3d0f89bb JB |
225 | else { |
226 | struct configfs_dirent *sd = dentry->d_fsdata; | |
227 | if (sd) { | |
228 | list_del_init(&sd->s_sibling); | |
229 | configfs_put(sd); | |
230 | } | |
231 | } | |
7063fbf2 JB |
232 | } |
233 | return err; | |
234 | } | |
235 | ||
236 | static void remove_dir(struct dentry * d) | |
237 | { | |
238 | struct dentry * parent = dget(d->d_parent); | |
239 | struct configfs_dirent * sd; | |
240 | ||
241 | sd = d->d_fsdata; | |
e7515d06 | 242 | list_del_init(&sd->s_sibling); |
7063fbf2 JB |
243 | configfs_put(sd); |
244 | if (d->d_inode) | |
245 | simple_rmdir(parent->d_inode,d); | |
246 | ||
247 | pr_debug(" o %s removing done (%d)\n",d->d_name.name, | |
248 | atomic_read(&d->d_count)); | |
249 | ||
250 | dput(parent); | |
251 | } | |
252 | ||
253 | /** | |
254 | * configfs_remove_dir - remove an config_item's directory. | |
255 | * @item: config_item we're removing. | |
256 | * | |
257 | * The only thing special about this is that we remove any files in | |
258 | * the directory before we remove the directory, and we've inlined | |
259 | * what used to be configfs_rmdir() below, instead of calling separately. | |
260 | */ | |
261 | ||
262 | static void configfs_remove_dir(struct config_item * item) | |
263 | { | |
264 | struct dentry * dentry = dget(item->ci_dentry); | |
265 | ||
266 | if (!dentry) | |
267 | return; | |
268 | ||
269 | remove_dir(dentry); | |
270 | /** | |
271 | * Drop reference from dget() on entrance. | |
272 | */ | |
273 | dput(dentry); | |
274 | } | |
275 | ||
276 | ||
277 | /* attaches attribute's configfs_dirent to the dentry corresponding to the | |
278 | * attribute file | |
279 | */ | |
280 | static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry) | |
281 | { | |
282 | struct configfs_attribute * attr = sd->s_element; | |
283 | int error; | |
284 | ||
3d0f89bb JB |
285 | dentry->d_fsdata = configfs_get(sd); |
286 | sd->s_dentry = dentry; | |
7063fbf2 | 287 | error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG, init_file); |
3d0f89bb JB |
288 | if (error) { |
289 | configfs_put(sd); | |
7063fbf2 | 290 | return error; |
3d0f89bb | 291 | } |
7063fbf2 JB |
292 | |
293 | dentry->d_op = &configfs_dentry_ops; | |
7063fbf2 JB |
294 | d_rehash(dentry); |
295 | ||
296 | return 0; | |
297 | } | |
298 | ||
299 | static struct dentry * configfs_lookup(struct inode *dir, | |
300 | struct dentry *dentry, | |
301 | struct nameidata *nd) | |
302 | { | |
303 | struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata; | |
304 | struct configfs_dirent * sd; | |
305 | int found = 0; | |
306 | int err = 0; | |
307 | ||
308 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
309 | if (sd->s_type & CONFIGFS_NOT_PINNED) { | |
310 | const unsigned char * name = configfs_get_name(sd); | |
311 | ||
312 | if (strcmp(name, dentry->d_name.name)) | |
313 | continue; | |
314 | ||
315 | found = 1; | |
316 | err = configfs_attach_attr(sd, dentry); | |
317 | break; | |
318 | } | |
319 | } | |
320 | ||
321 | if (!found) { | |
322 | /* | |
323 | * If it doesn't exist and it isn't a NOT_PINNED item, | |
324 | * it must be negative. | |
325 | */ | |
326 | return simple_lookup(dir, dentry, nd); | |
327 | } | |
328 | ||
329 | return ERR_PTR(err); | |
330 | } | |
331 | ||
332 | /* | |
333 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are | |
1b1dcc1b | 334 | * attributes and are removed by rmdir(). We recurse, taking i_mutex |
7063fbf2 JB |
335 | * on all children that are candidates for default detach. If the |
336 | * result is clean, then configfs_detach_group() will handle dropping | |
1b1dcc1b | 337 | * i_mutex. If there is an error, the caller will clean up the i_mutex |
7063fbf2 JB |
338 | * holders via configfs_detach_rollback(). |
339 | */ | |
340 | static int configfs_detach_prep(struct dentry *dentry) | |
341 | { | |
342 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
343 | struct configfs_dirent *sd; | |
344 | int ret; | |
345 | ||
346 | ret = -EBUSY; | |
347 | if (!list_empty(&parent_sd->s_links)) | |
348 | goto out; | |
349 | ||
350 | ret = 0; | |
351 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
352 | if (sd->s_type & CONFIGFS_NOT_PINNED) | |
353 | continue; | |
354 | if (sd->s_type & CONFIGFS_USET_DEFAULT) { | |
1b1dcc1b JS |
355 | mutex_lock(&sd->s_dentry->d_inode->i_mutex); |
356 | /* Mark that we've taken i_mutex */ | |
7063fbf2 JB |
357 | sd->s_type |= CONFIGFS_USET_DROPPING; |
358 | ||
359 | ret = configfs_detach_prep(sd->s_dentry); | |
360 | if (!ret) | |
e7515d06 | 361 | continue; |
7063fbf2 JB |
362 | } else |
363 | ret = -ENOTEMPTY; | |
364 | ||
365 | break; | |
366 | } | |
367 | ||
368 | out: | |
369 | return ret; | |
370 | } | |
371 | ||
372 | /* | |
1b1dcc1b | 373 | * Walk the tree, dropping i_mutex wherever CONFIGFS_USET_DROPPING is |
7063fbf2 JB |
374 | * set. |
375 | */ | |
376 | static void configfs_detach_rollback(struct dentry *dentry) | |
377 | { | |
378 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
379 | struct configfs_dirent *sd; | |
380 | ||
381 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
382 | if (sd->s_type & CONFIGFS_USET_DEFAULT) { | |
383 | configfs_detach_rollback(sd->s_dentry); | |
384 | ||
385 | if (sd->s_type & CONFIGFS_USET_DROPPING) { | |
386 | sd->s_type &= ~CONFIGFS_USET_DROPPING; | |
1b1dcc1b | 387 | mutex_unlock(&sd->s_dentry->d_inode->i_mutex); |
7063fbf2 JB |
388 | } |
389 | } | |
390 | } | |
391 | } | |
392 | ||
393 | static void detach_attrs(struct config_item * item) | |
394 | { | |
395 | struct dentry * dentry = dget(item->ci_dentry); | |
396 | struct configfs_dirent * parent_sd; | |
397 | struct configfs_dirent * sd, * tmp; | |
398 | ||
399 | if (!dentry) | |
400 | return; | |
401 | ||
402 | pr_debug("configfs %s: dropping attrs for dir\n", | |
403 | dentry->d_name.name); | |
404 | ||
405 | parent_sd = dentry->d_fsdata; | |
406 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
407 | if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED)) | |
408 | continue; | |
409 | list_del_init(&sd->s_sibling); | |
410 | configfs_drop_dentry(sd, dentry); | |
411 | configfs_put(sd); | |
412 | } | |
413 | ||
414 | /** | |
415 | * Drop reference from dget() on entrance. | |
416 | */ | |
417 | dput(dentry); | |
418 | } | |
419 | ||
420 | static int populate_attrs(struct config_item *item) | |
421 | { | |
422 | struct config_item_type *t = item->ci_type; | |
423 | struct configfs_attribute *attr; | |
424 | int error = 0; | |
425 | int i; | |
426 | ||
427 | if (!t) | |
428 | return -EINVAL; | |
429 | if (t->ct_attrs) { | |
430 | for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) { | |
431 | if ((error = configfs_create_file(item, attr))) | |
432 | break; | |
433 | } | |
434 | } | |
435 | ||
436 | if (error) | |
437 | detach_attrs(item); | |
438 | ||
439 | return error; | |
440 | } | |
441 | ||
442 | static int configfs_attach_group(struct config_item *parent_item, | |
443 | struct config_item *item, | |
444 | struct dentry *dentry); | |
445 | static void configfs_detach_group(struct config_item *item); | |
446 | ||
447 | static void detach_groups(struct config_group *group) | |
448 | { | |
449 | struct dentry * dentry = dget(group->cg_item.ci_dentry); | |
450 | struct dentry *child; | |
451 | struct configfs_dirent *parent_sd; | |
452 | struct configfs_dirent *sd, *tmp; | |
453 | ||
454 | if (!dentry) | |
455 | return; | |
456 | ||
457 | parent_sd = dentry->d_fsdata; | |
458 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
459 | if (!sd->s_element || | |
460 | !(sd->s_type & CONFIGFS_USET_DEFAULT)) | |
461 | continue; | |
462 | ||
463 | child = sd->s_dentry; | |
464 | ||
465 | configfs_detach_group(sd->s_element); | |
466 | child->d_inode->i_flags |= S_DEAD; | |
467 | ||
468 | /* | |
469 | * From rmdir/unregister, a configfs_detach_prep() pass | |
1b1dcc1b | 470 | * has taken our i_mutex for us. Drop it. |
7063fbf2 JB |
471 | * From mkdir/register cleanup, there is no sem held. |
472 | */ | |
473 | if (sd->s_type & CONFIGFS_USET_DROPPING) | |
1b1dcc1b | 474 | mutex_unlock(&child->d_inode->i_mutex); |
7063fbf2 JB |
475 | |
476 | d_delete(child); | |
477 | dput(child); | |
478 | } | |
479 | ||
480 | /** | |
481 | * Drop reference from dget() on entrance. | |
482 | */ | |
483 | dput(dentry); | |
484 | } | |
485 | ||
486 | /* | |
487 | * This fakes mkdir(2) on a default_groups[] entry. It | |
488 | * creates a dentry, attachs it, and then does fixup | |
489 | * on the sd->s_type. | |
490 | * | |
491 | * We could, perhaps, tweak our parent's ->mkdir for a minute and | |
492 | * try using vfs_mkdir. Just a thought. | |
493 | */ | |
494 | static int create_default_group(struct config_group *parent_group, | |
495 | struct config_group *group) | |
496 | { | |
497 | int ret; | |
498 | struct qstr name; | |
499 | struct configfs_dirent *sd; | |
500 | /* We trust the caller holds a reference to parent */ | |
501 | struct dentry *child, *parent = parent_group->cg_item.ci_dentry; | |
502 | ||
503 | if (!group->cg_item.ci_name) | |
504 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
505 | name.name = group->cg_item.ci_name; | |
506 | name.len = strlen(name.name); | |
507 | name.hash = full_name_hash(name.name, name.len); | |
508 | ||
509 | ret = -ENOMEM; | |
510 | child = d_alloc(parent, &name); | |
511 | if (child) { | |
512 | d_add(child, NULL); | |
513 | ||
514 | ret = configfs_attach_group(&parent_group->cg_item, | |
515 | &group->cg_item, child); | |
516 | if (!ret) { | |
517 | sd = child->d_fsdata; | |
518 | sd->s_type |= CONFIGFS_USET_DEFAULT; | |
519 | } else { | |
520 | d_delete(child); | |
521 | dput(child); | |
522 | } | |
523 | } | |
524 | ||
525 | return ret; | |
526 | } | |
527 | ||
528 | static int populate_groups(struct config_group *group) | |
529 | { | |
530 | struct config_group *new_group; | |
531 | struct dentry *dentry = group->cg_item.ci_dentry; | |
532 | int ret = 0; | |
533 | int i; | |
534 | ||
cbca692c | 535 | if (group->default_groups) { |
eed7a0db JB |
536 | /* |
537 | * FYI, we're faking mkdir here | |
7063fbf2 JB |
538 | * I'm not sure we need this semaphore, as we're called |
539 | * from our parent's mkdir. That holds our parent's | |
1b1dcc1b | 540 | * i_mutex, so afaik lookup cannot continue through our |
7063fbf2 | 541 | * parent to find us, let alone mess with our tree. |
1b1dcc1b | 542 | * That said, taking our i_mutex is closer to mkdir |
eed7a0db JB |
543 | * emulation, and shouldn't hurt. |
544 | */ | |
1b1dcc1b | 545 | mutex_lock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
546 | |
547 | for (i = 0; group->default_groups[i]; i++) { | |
548 | new_group = group->default_groups[i]; | |
549 | ||
550 | ret = create_default_group(group, new_group); | |
551 | if (ret) | |
552 | break; | |
553 | } | |
554 | ||
1b1dcc1b | 555 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
556 | } |
557 | ||
558 | if (ret) | |
559 | detach_groups(group); | |
560 | ||
561 | return ret; | |
562 | } | |
563 | ||
564 | /* | |
565 | * All of link_obj/unlink_obj/link_group/unlink_group require that | |
566 | * subsys->su_sem is held. | |
567 | */ | |
568 | ||
569 | static void unlink_obj(struct config_item *item) | |
570 | { | |
571 | struct config_group *group; | |
572 | ||
573 | group = item->ci_group; | |
574 | if (group) { | |
575 | list_del_init(&item->ci_entry); | |
576 | ||
577 | item->ci_group = NULL; | |
578 | item->ci_parent = NULL; | |
eed7a0db JB |
579 | |
580 | /* Drop the reference for ci_entry */ | |
7063fbf2 JB |
581 | config_item_put(item); |
582 | ||
eed7a0db | 583 | /* Drop the reference for ci_parent */ |
7063fbf2 JB |
584 | config_group_put(group); |
585 | } | |
586 | } | |
587 | ||
588 | static void link_obj(struct config_item *parent_item, struct config_item *item) | |
589 | { | |
eed7a0db JB |
590 | /* |
591 | * Parent seems redundant with group, but it makes certain | |
592 | * traversals much nicer. | |
593 | */ | |
7063fbf2 | 594 | item->ci_parent = parent_item; |
eed7a0db JB |
595 | |
596 | /* | |
597 | * We hold a reference on the parent for the child's ci_parent | |
598 | * link. | |
599 | */ | |
7063fbf2 JB |
600 | item->ci_group = config_group_get(to_config_group(parent_item)); |
601 | list_add_tail(&item->ci_entry, &item->ci_group->cg_children); | |
602 | ||
eed7a0db JB |
603 | /* |
604 | * We hold a reference on the child for ci_entry on the parent's | |
605 | * cg_children | |
606 | */ | |
7063fbf2 JB |
607 | config_item_get(item); |
608 | } | |
609 | ||
610 | static void unlink_group(struct config_group *group) | |
611 | { | |
612 | int i; | |
613 | struct config_group *new_group; | |
614 | ||
615 | if (group->default_groups) { | |
616 | for (i = 0; group->default_groups[i]; i++) { | |
617 | new_group = group->default_groups[i]; | |
618 | unlink_group(new_group); | |
619 | } | |
620 | } | |
621 | ||
622 | group->cg_subsys = NULL; | |
623 | unlink_obj(&group->cg_item); | |
624 | } | |
625 | ||
626 | static void link_group(struct config_group *parent_group, struct config_group *group) | |
627 | { | |
628 | int i; | |
629 | struct config_group *new_group; | |
630 | struct configfs_subsystem *subsys = NULL; /* gcc is a turd */ | |
631 | ||
632 | link_obj(&parent_group->cg_item, &group->cg_item); | |
633 | ||
634 | if (parent_group->cg_subsys) | |
635 | subsys = parent_group->cg_subsys; | |
636 | else if (configfs_is_root(&parent_group->cg_item)) | |
637 | subsys = to_configfs_subsystem(group); | |
638 | else | |
639 | BUG(); | |
640 | group->cg_subsys = subsys; | |
641 | ||
642 | if (group->default_groups) { | |
643 | for (i = 0; group->default_groups[i]; i++) { | |
644 | new_group = group->default_groups[i]; | |
645 | link_group(group, new_group); | |
646 | } | |
647 | } | |
648 | } | |
649 | ||
650 | /* | |
651 | * The goal is that configfs_attach_item() (and | |
652 | * configfs_attach_group()) can be called from either the VFS or this | |
653 | * module. That is, they assume that the items have been created, | |
654 | * the dentry allocated, and the dcache is all ready to go. | |
655 | * | |
656 | * If they fail, they must clean up after themselves as if they | |
657 | * had never been called. The caller (VFS or local function) will | |
658 | * handle cleaning up the dcache bits. | |
659 | * | |
660 | * configfs_detach_group() and configfs_detach_item() behave similarly on | |
661 | * the way out. They assume that the proper semaphores are held, they | |
662 | * clean up the configfs items, and they expect their callers will | |
663 | * handle the dcache bits. | |
664 | */ | |
665 | static int configfs_attach_item(struct config_item *parent_item, | |
666 | struct config_item *item, | |
667 | struct dentry *dentry) | |
668 | { | |
669 | int ret; | |
670 | ||
671 | ret = configfs_create_dir(item, dentry); | |
672 | if (!ret) { | |
673 | ret = populate_attrs(item); | |
674 | if (ret) { | |
675 | configfs_remove_dir(item); | |
676 | d_delete(dentry); | |
677 | } | |
678 | } | |
679 | ||
680 | return ret; | |
681 | } | |
682 | ||
683 | static void configfs_detach_item(struct config_item *item) | |
684 | { | |
685 | detach_attrs(item); | |
686 | configfs_remove_dir(item); | |
687 | } | |
688 | ||
689 | static int configfs_attach_group(struct config_item *parent_item, | |
690 | struct config_item *item, | |
691 | struct dentry *dentry) | |
692 | { | |
693 | int ret; | |
694 | struct configfs_dirent *sd; | |
695 | ||
696 | ret = configfs_attach_item(parent_item, item, dentry); | |
697 | if (!ret) { | |
698 | sd = dentry->d_fsdata; | |
699 | sd->s_type |= CONFIGFS_USET_DIR; | |
700 | ||
701 | ret = populate_groups(to_config_group(item)); | |
702 | if (ret) { | |
703 | configfs_detach_item(item); | |
704 | d_delete(dentry); | |
705 | } | |
706 | } | |
707 | ||
708 | return ret; | |
709 | } | |
710 | ||
711 | static void configfs_detach_group(struct config_item *item) | |
712 | { | |
713 | detach_groups(to_config_group(item)); | |
714 | configfs_detach_item(item); | |
715 | } | |
716 | ||
717 | /* | |
718 | * Drop the initial reference from make_item()/make_group() | |
719 | * This function assumes that reference is held on item | |
720 | * and that item holds a valid reference to the parent. Also, it | |
721 | * assumes the caller has validated ci_type. | |
722 | */ | |
723 | static void client_drop_item(struct config_item *parent_item, | |
724 | struct config_item *item) | |
725 | { | |
726 | struct config_item_type *type; | |
727 | ||
728 | type = parent_item->ci_type; | |
729 | BUG_ON(!type); | |
730 | ||
eed7a0db JB |
731 | /* |
732 | * If ->drop_item() exists, it is responsible for the | |
733 | * config_item_put(). | |
734 | */ | |
7063fbf2 JB |
735 | if (type->ct_group_ops && type->ct_group_ops->drop_item) |
736 | type->ct_group_ops->drop_item(to_config_group(parent_item), | |
737 | item); | |
738 | else | |
739 | config_item_put(item); | |
740 | } | |
741 | ||
742 | ||
743 | static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
744 | { | |
eed7a0db | 745 | int ret, module_got = 0; |
7063fbf2 JB |
746 | struct config_group *group; |
747 | struct config_item *item; | |
748 | struct config_item *parent_item; | |
749 | struct configfs_subsystem *subsys; | |
750 | struct configfs_dirent *sd; | |
751 | struct config_item_type *type; | |
eed7a0db | 752 | struct module *owner = NULL; |
7063fbf2 JB |
753 | char *name; |
754 | ||
84efad1a JB |
755 | if (dentry->d_parent == configfs_sb->s_root) { |
756 | ret = -EPERM; | |
757 | goto out; | |
758 | } | |
7063fbf2 JB |
759 | |
760 | sd = dentry->d_parent->d_fsdata; | |
84efad1a JB |
761 | if (!(sd->s_type & CONFIGFS_USET_DIR)) { |
762 | ret = -EPERM; | |
763 | goto out; | |
764 | } | |
7063fbf2 | 765 | |
84efad1a | 766 | /* Get a working ref for the duration of this function */ |
7063fbf2 JB |
767 | parent_item = configfs_get_config_item(dentry->d_parent); |
768 | type = parent_item->ci_type; | |
769 | subsys = to_config_group(parent_item)->cg_subsys; | |
770 | BUG_ON(!subsys); | |
771 | ||
772 | if (!type || !type->ct_group_ops || | |
773 | (!type->ct_group_ops->make_group && | |
774 | !type->ct_group_ops->make_item)) { | |
84efad1a JB |
775 | ret = -EPERM; /* Lack-of-mkdir returns -EPERM */ |
776 | goto out_put; | |
7063fbf2 JB |
777 | } |
778 | ||
779 | name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL); | |
780 | if (!name) { | |
84efad1a JB |
781 | ret = -ENOMEM; |
782 | goto out_put; | |
7063fbf2 | 783 | } |
84efad1a | 784 | |
7063fbf2 JB |
785 | snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name); |
786 | ||
787 | down(&subsys->su_sem); | |
788 | group = NULL; | |
789 | item = NULL; | |
790 | if (type->ct_group_ops->make_group) { | |
791 | group = type->ct_group_ops->make_group(to_config_group(parent_item), name); | |
792 | if (group) { | |
793 | link_group(to_config_group(parent_item), group); | |
794 | item = &group->cg_item; | |
795 | } | |
796 | } else { | |
797 | item = type->ct_group_ops->make_item(to_config_group(parent_item), name); | |
798 | if (item) | |
799 | link_obj(parent_item, item); | |
800 | } | |
801 | up(&subsys->su_sem); | |
802 | ||
803 | kfree(name); | |
804 | if (!item) { | |
eed7a0db JB |
805 | /* |
806 | * If item == NULL, then link_obj() was never called. | |
807 | * There are no extra references to clean up. | |
808 | */ | |
84efad1a JB |
809 | ret = -ENOMEM; |
810 | goto out_put; | |
7063fbf2 JB |
811 | } |
812 | ||
eed7a0db JB |
813 | /* |
814 | * link_obj() has been called (via link_group() for groups). | |
815 | * From here on out, errors must clean that up. | |
816 | */ | |
817 | ||
7063fbf2 | 818 | type = item->ci_type; |
eed7a0db JB |
819 | if (!type) { |
820 | ret = -EINVAL; | |
821 | goto out_unlink; | |
822 | } | |
7063fbf2 | 823 | |
eed7a0db JB |
824 | owner = type->ct_owner; |
825 | if (!try_module_get(owner)) { | |
826 | ret = -EINVAL; | |
827 | goto out_unlink; | |
828 | } | |
7063fbf2 | 829 | |
eed7a0db JB |
830 | /* |
831 | * I hate doing it this way, but if there is | |
832 | * an error, module_put() probably should | |
833 | * happen after any cleanup. | |
834 | */ | |
835 | module_got = 1; | |
836 | ||
837 | if (group) | |
838 | ret = configfs_attach_group(parent_item, item, dentry); | |
839 | else | |
840 | ret = configfs_attach_item(parent_item, item, dentry); | |
841 | ||
842 | out_unlink: | |
843 | if (ret) { | |
844 | /* Tear down everything we built up */ | |
845 | down(&subsys->su_sem); | |
846 | if (group) | |
847 | unlink_group(group); | |
848 | else | |
849 | unlink_obj(item); | |
850 | client_drop_item(parent_item, item); | |
851 | up(&subsys->su_sem); | |
852 | ||
853 | if (module_got) | |
854 | module_put(owner); | |
7063fbf2 JB |
855 | } |
856 | ||
84efad1a JB |
857 | out_put: |
858 | /* | |
eed7a0db JB |
859 | * link_obj()/link_group() took a reference from child->parent, |
860 | * so the parent is safely pinned. We can drop our working | |
861 | * reference. | |
84efad1a JB |
862 | */ |
863 | config_item_put(parent_item); | |
864 | ||
865 | out: | |
7063fbf2 JB |
866 | return ret; |
867 | } | |
868 | ||
869 | static int configfs_rmdir(struct inode *dir, struct dentry *dentry) | |
870 | { | |
871 | struct config_item *parent_item; | |
872 | struct config_item *item; | |
873 | struct configfs_subsystem *subsys; | |
874 | struct configfs_dirent *sd; | |
875 | struct module *owner = NULL; | |
876 | int ret; | |
877 | ||
878 | if (dentry->d_parent == configfs_sb->s_root) | |
879 | return -EPERM; | |
880 | ||
881 | sd = dentry->d_fsdata; | |
882 | if (sd->s_type & CONFIGFS_USET_DEFAULT) | |
883 | return -EPERM; | |
884 | ||
84efad1a | 885 | /* Get a working ref until we have the child */ |
7063fbf2 JB |
886 | parent_item = configfs_get_config_item(dentry->d_parent); |
887 | subsys = to_config_group(parent_item)->cg_subsys; | |
888 | BUG_ON(!subsys); | |
889 | ||
890 | if (!parent_item->ci_type) { | |
891 | config_item_put(parent_item); | |
892 | return -EINVAL; | |
893 | } | |
894 | ||
895 | ret = configfs_detach_prep(dentry); | |
896 | if (ret) { | |
897 | configfs_detach_rollback(dentry); | |
898 | config_item_put(parent_item); | |
899 | return ret; | |
900 | } | |
901 | ||
84efad1a | 902 | /* Get a working ref for the duration of this function */ |
7063fbf2 JB |
903 | item = configfs_get_config_item(dentry); |
904 | ||
905 | /* Drop reference from above, item already holds one. */ | |
906 | config_item_put(parent_item); | |
907 | ||
908 | if (item->ci_type) | |
909 | owner = item->ci_type->ct_owner; | |
910 | ||
911 | if (sd->s_type & CONFIGFS_USET_DIR) { | |
912 | configfs_detach_group(item); | |
913 | ||
914 | down(&subsys->su_sem); | |
915 | unlink_group(to_config_group(item)); | |
916 | } else { | |
917 | configfs_detach_item(item); | |
918 | ||
919 | down(&subsys->su_sem); | |
920 | unlink_obj(item); | |
921 | } | |
922 | ||
923 | client_drop_item(parent_item, item); | |
924 | up(&subsys->su_sem); | |
925 | ||
926 | /* Drop our reference from above */ | |
927 | config_item_put(item); | |
928 | ||
929 | module_put(owner); | |
930 | ||
931 | return 0; | |
932 | } | |
933 | ||
934 | struct inode_operations configfs_dir_inode_operations = { | |
935 | .mkdir = configfs_mkdir, | |
936 | .rmdir = configfs_rmdir, | |
937 | .symlink = configfs_symlink, | |
938 | .unlink = configfs_unlink, | |
939 | .lookup = configfs_lookup, | |
3d0f89bb | 940 | .setattr = configfs_setattr, |
7063fbf2 JB |
941 | }; |
942 | ||
943 | #if 0 | |
944 | int configfs_rename_dir(struct config_item * item, const char *new_name) | |
945 | { | |
946 | int error = 0; | |
947 | struct dentry * new_dentry, * parent; | |
948 | ||
949 | if (!strcmp(config_item_name(item), new_name)) | |
950 | return -EINVAL; | |
951 | ||
952 | if (!item->parent) | |
953 | return -EINVAL; | |
954 | ||
955 | down_write(&configfs_rename_sem); | |
956 | parent = item->parent->dentry; | |
957 | ||
1b1dcc1b | 958 | mutex_lock(&parent->d_inode->i_mutex); |
7063fbf2 JB |
959 | |
960 | new_dentry = lookup_one_len(new_name, parent, strlen(new_name)); | |
961 | if (!IS_ERR(new_dentry)) { | |
e7515d06 | 962 | if (!new_dentry->d_inode) { |
7063fbf2 JB |
963 | error = config_item_set_name(item, "%s", new_name); |
964 | if (!error) { | |
965 | d_add(new_dentry, NULL); | |
966 | d_move(item->dentry, new_dentry); | |
967 | } | |
968 | else | |
969 | d_delete(new_dentry); | |
970 | } else | |
971 | error = -EEXIST; | |
972 | dput(new_dentry); | |
973 | } | |
1b1dcc1b | 974 | mutex_unlock(&parent->d_inode->i_mutex); |
7063fbf2 JB |
975 | up_write(&configfs_rename_sem); |
976 | ||
977 | return error; | |
978 | } | |
979 | #endif | |
980 | ||
981 | static int configfs_dir_open(struct inode *inode, struct file *file) | |
982 | { | |
867fa491 | 983 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 JB |
984 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
985 | ||
1b1dcc1b | 986 | mutex_lock(&dentry->d_inode->i_mutex); |
7063fbf2 | 987 | file->private_data = configfs_new_dirent(parent_sd, NULL); |
1b1dcc1b | 988 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
989 | |
990 | return file->private_data ? 0 : -ENOMEM; | |
991 | ||
992 | } | |
993 | ||
994 | static int configfs_dir_close(struct inode *inode, struct file *file) | |
995 | { | |
867fa491 | 996 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 JB |
997 | struct configfs_dirent * cursor = file->private_data; |
998 | ||
1b1dcc1b | 999 | mutex_lock(&dentry->d_inode->i_mutex); |
7063fbf2 | 1000 | list_del_init(&cursor->s_sibling); |
1b1dcc1b | 1001 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1002 | |
1003 | release_configfs_dirent(cursor); | |
1004 | ||
1005 | return 0; | |
1006 | } | |
1007 | ||
1008 | /* Relationship between s_mode and the DT_xxx types */ | |
1009 | static inline unsigned char dt_type(struct configfs_dirent *sd) | |
1010 | { | |
1011 | return (sd->s_mode >> 12) & 15; | |
1012 | } | |
1013 | ||
1014 | static int configfs_readdir(struct file * filp, void * dirent, filldir_t filldir) | |
1015 | { | |
867fa491 | 1016 | struct dentry *dentry = filp->f_path.dentry; |
7063fbf2 JB |
1017 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
1018 | struct configfs_dirent *cursor = filp->private_data; | |
1019 | struct list_head *p, *q = &cursor->s_sibling; | |
1020 | ino_t ino; | |
1021 | int i = filp->f_pos; | |
1022 | ||
1023 | switch (i) { | |
1024 | case 0: | |
1025 | ino = dentry->d_inode->i_ino; | |
1026 | if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) | |
1027 | break; | |
1028 | filp->f_pos++; | |
1029 | i++; | |
1030 | /* fallthrough */ | |
1031 | case 1: | |
1032 | ino = parent_ino(dentry); | |
1033 | if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) | |
1034 | break; | |
1035 | filp->f_pos++; | |
1036 | i++; | |
1037 | /* fallthrough */ | |
1038 | default: | |
1039 | if (filp->f_pos == 2) { | |
f116629d | 1040 | list_move(q, &parent_sd->s_children); |
7063fbf2 JB |
1041 | } |
1042 | for (p=q->next; p!= &parent_sd->s_children; p=p->next) { | |
1043 | struct configfs_dirent *next; | |
1044 | const char * name; | |
1045 | int len; | |
1046 | ||
1047 | next = list_entry(p, struct configfs_dirent, | |
1048 | s_sibling); | |
1049 | if (!next->s_element) | |
1050 | continue; | |
1051 | ||
1052 | name = configfs_get_name(next); | |
1053 | len = strlen(name); | |
1054 | if (next->s_dentry) | |
1055 | ino = next->s_dentry->d_inode->i_ino; | |
1056 | else | |
1057 | ino = iunique(configfs_sb, 2); | |
1058 | ||
1059 | if (filldir(dirent, name, len, filp->f_pos, ino, | |
1060 | dt_type(next)) < 0) | |
1061 | return 0; | |
1062 | ||
f116629d | 1063 | list_move(q, p); |
7063fbf2 JB |
1064 | p = q; |
1065 | filp->f_pos++; | |
1066 | } | |
1067 | } | |
1068 | return 0; | |
1069 | } | |
1070 | ||
1071 | static loff_t configfs_dir_lseek(struct file * file, loff_t offset, int origin) | |
1072 | { | |
867fa491 | 1073 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 | 1074 | |
1b1dcc1b | 1075 | mutex_lock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1076 | switch (origin) { |
1077 | case 1: | |
1078 | offset += file->f_pos; | |
1079 | case 0: | |
1080 | if (offset >= 0) | |
1081 | break; | |
1082 | default: | |
867fa491 | 1083 | mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); |
7063fbf2 JB |
1084 | return -EINVAL; |
1085 | } | |
1086 | if (offset != file->f_pos) { | |
1087 | file->f_pos = offset; | |
1088 | if (file->f_pos >= 2) { | |
1089 | struct configfs_dirent *sd = dentry->d_fsdata; | |
1090 | struct configfs_dirent *cursor = file->private_data; | |
1091 | struct list_head *p; | |
1092 | loff_t n = file->f_pos - 2; | |
1093 | ||
1094 | list_del(&cursor->s_sibling); | |
1095 | p = sd->s_children.next; | |
1096 | while (n && p != &sd->s_children) { | |
1097 | struct configfs_dirent *next; | |
1098 | next = list_entry(p, struct configfs_dirent, | |
1099 | s_sibling); | |
1100 | if (next->s_element) | |
1101 | n--; | |
1102 | p = p->next; | |
1103 | } | |
1104 | list_add_tail(&cursor->s_sibling, p); | |
1105 | } | |
1106 | } | |
1b1dcc1b | 1107 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1108 | return offset; |
1109 | } | |
1110 | ||
4b6f5d20 | 1111 | const struct file_operations configfs_dir_operations = { |
7063fbf2 JB |
1112 | .open = configfs_dir_open, |
1113 | .release = configfs_dir_close, | |
1114 | .llseek = configfs_dir_lseek, | |
1115 | .read = generic_read_dir, | |
1116 | .readdir = configfs_readdir, | |
1117 | }; | |
1118 | ||
1119 | int configfs_register_subsystem(struct configfs_subsystem *subsys) | |
1120 | { | |
1121 | int err; | |
1122 | struct config_group *group = &subsys->su_group; | |
1123 | struct qstr name; | |
1124 | struct dentry *dentry; | |
1125 | struct configfs_dirent *sd; | |
1126 | ||
1127 | err = configfs_pin_fs(); | |
1128 | if (err) | |
1129 | return err; | |
1130 | ||
1131 | if (!group->cg_item.ci_name) | |
1132 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
1133 | ||
1134 | sd = configfs_sb->s_root->d_fsdata; | |
1135 | link_group(to_config_group(sd->s_element), group); | |
1136 | ||
1b1dcc1b | 1137 | mutex_lock(&configfs_sb->s_root->d_inode->i_mutex); |
7063fbf2 JB |
1138 | |
1139 | name.name = group->cg_item.ci_name; | |
1140 | name.len = strlen(name.name); | |
1141 | name.hash = full_name_hash(name.name, name.len); | |
1142 | ||
1143 | err = -ENOMEM; | |
1144 | dentry = d_alloc(configfs_sb->s_root, &name); | |
1145 | if (!dentry) | |
1146 | goto out_release; | |
1147 | ||
1148 | d_add(dentry, NULL); | |
1149 | ||
1150 | err = configfs_attach_group(sd->s_element, &group->cg_item, | |
1151 | dentry); | |
1152 | if (!err) | |
1153 | dentry = NULL; | |
1154 | else | |
1155 | d_delete(dentry); | |
1156 | ||
1b1dcc1b | 1157 | mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex); |
7063fbf2 JB |
1158 | |
1159 | if (dentry) { | |
1160 | dput(dentry); | |
1161 | out_release: | |
1162 | unlink_group(group); | |
1163 | configfs_release_fs(); | |
1164 | } | |
1165 | ||
1166 | return err; | |
1167 | } | |
1168 | ||
1169 | void configfs_unregister_subsystem(struct configfs_subsystem *subsys) | |
1170 | { | |
1171 | struct config_group *group = &subsys->su_group; | |
1172 | struct dentry *dentry = group->cg_item.ci_dentry; | |
1173 | ||
1174 | if (dentry->d_parent != configfs_sb->s_root) { | |
1175 | printk(KERN_ERR "configfs: Tried to unregister non-subsystem!\n"); | |
1176 | return; | |
1177 | } | |
1178 | ||
55ed1602 MF |
1179 | mutex_lock_nested(&configfs_sb->s_root->d_inode->i_mutex, |
1180 | I_MUTEX_PARENT); | |
1181 | mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); | |
7063fbf2 JB |
1182 | if (configfs_detach_prep(dentry)) { |
1183 | printk(KERN_ERR "configfs: Tried to unregister non-empty subsystem!\n"); | |
1184 | } | |
1185 | configfs_detach_group(&group->cg_item); | |
1186 | dentry->d_inode->i_flags |= S_DEAD; | |
1b1dcc1b | 1187 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1188 | |
1189 | d_delete(dentry); | |
1190 | ||
1b1dcc1b | 1191 | mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex); |
7063fbf2 JB |
1192 | |
1193 | dput(dentry); | |
1194 | ||
1195 | unlink_group(group); | |
1196 | configfs_release_fs(); | |
1197 | } | |
1198 | ||
1199 | EXPORT_SYMBOL(configfs_register_subsystem); | |
1200 | EXPORT_SYMBOL(configfs_unregister_subsystem); |