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