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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> | |
107ed40b | 33 | #include <linux/err.h> |
7063fbf2 JB |
34 | |
35 | #include <linux/configfs.h> | |
36 | #include "configfs_internal.h" | |
37 | ||
38 | DECLARE_RWSEM(configfs_rename_sem); | |
6f610764 LR |
39 | /* |
40 | * Protects mutations of configfs_dirent linkage together with proper i_mutex | |
5301a77d | 41 | * Also protects mutations of symlinks linkage to target configfs_dirent |
6f610764 LR |
42 | * Mutators of configfs_dirent linkage must *both* have the proper inode locked |
43 | * and configfs_dirent_lock locked, in that order. | |
5301a77d LR |
44 | * This allows one to safely traverse configfs_dirent trees and symlinks without |
45 | * having to lock inodes. | |
b3e76af8 LR |
46 | * |
47 | * Protects setting of CONFIGFS_USET_DROPPING: checking the flag | |
48 | * unlocked is not reliable unless in detach_groups() called from | |
49 | * rmdir()/unregister() and from configfs_attach_group() | |
6f610764 LR |
50 | */ |
51 | DEFINE_SPINLOCK(configfs_dirent_lock); | |
7063fbf2 JB |
52 | |
53 | static void configfs_d_iput(struct dentry * dentry, | |
54 | struct inode * inode) | |
55 | { | |
56 | struct configfs_dirent * sd = dentry->d_fsdata; | |
57 | ||
58 | if (sd) { | |
59 | BUG_ON(sd->s_dentry != dentry); | |
60 | sd->s_dentry = NULL; | |
61 | configfs_put(sd); | |
62 | } | |
63 | iput(inode); | |
64 | } | |
65 | ||
66 | /* | |
67 | * We _must_ delete our dentries on last dput, as the chain-to-parent | |
68 | * behavior is required to clear the parents of default_groups. | |
69 | */ | |
70 | static int configfs_d_delete(struct dentry *dentry) | |
71 | { | |
72 | return 1; | |
73 | } | |
74 | ||
75 | static struct dentry_operations configfs_dentry_ops = { | |
76 | .d_iput = configfs_d_iput, | |
77 | /* simple_delete_dentry() isn't exported */ | |
78 | .d_delete = configfs_d_delete, | |
79 | }; | |
80 | ||
81 | /* | |
82 | * Allocates a new configfs_dirent and links it to the parent configfs_dirent | |
83 | */ | |
84 | static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent * parent_sd, | |
85 | void * element) | |
86 | { | |
87 | struct configfs_dirent * sd; | |
88 | ||
c3762229 | 89 | sd = kmem_cache_zalloc(configfs_dir_cachep, GFP_KERNEL); |
7063fbf2 | 90 | if (!sd) |
107ed40b | 91 | return ERR_PTR(-ENOMEM); |
7063fbf2 | 92 | |
7063fbf2 JB |
93 | atomic_set(&sd->s_count, 1); |
94 | INIT_LIST_HEAD(&sd->s_links); | |
95 | INIT_LIST_HEAD(&sd->s_children); | |
7063fbf2 | 96 | sd->s_element = element; |
6f610764 | 97 | spin_lock(&configfs_dirent_lock); |
b3e76af8 LR |
98 | if (parent_sd->s_type & CONFIGFS_USET_DROPPING) { |
99 | spin_unlock(&configfs_dirent_lock); | |
100 | kmem_cache_free(configfs_dir_cachep, sd); | |
101 | return ERR_PTR(-ENOENT); | |
102 | } | |
6f610764 LR |
103 | list_add(&sd->s_sibling, &parent_sd->s_children); |
104 | spin_unlock(&configfs_dirent_lock); | |
7063fbf2 JB |
105 | |
106 | return sd; | |
107 | } | |
108 | ||
b4c98f62 JB |
109 | /* |
110 | * | |
111 | * Return -EEXIST if there is already a configfs element with the same | |
112 | * name for the same parent. | |
113 | * | |
114 | * called with parent inode's i_mutex held | |
115 | */ | |
58d206c2 AB |
116 | static int configfs_dirent_exists(struct configfs_dirent *parent_sd, |
117 | const unsigned char *new) | |
b4c98f62 JB |
118 | { |
119 | struct configfs_dirent * sd; | |
120 | ||
121 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
122 | if (sd->s_element) { | |
123 | const unsigned char *existing = configfs_get_name(sd); | |
124 | if (strcmp(existing, new)) | |
125 | continue; | |
126 | else | |
127 | return -EEXIST; | |
128 | } | |
129 | } | |
130 | ||
131 | return 0; | |
132 | } | |
133 | ||
134 | ||
7063fbf2 JB |
135 | int configfs_make_dirent(struct configfs_dirent * parent_sd, |
136 | struct dentry * dentry, void * element, | |
137 | umode_t mode, int type) | |
138 | { | |
139 | struct configfs_dirent * sd; | |
140 | ||
141 | sd = configfs_new_dirent(parent_sd, element); | |
107ed40b LR |
142 | if (IS_ERR(sd)) |
143 | return PTR_ERR(sd); | |
7063fbf2 JB |
144 | |
145 | sd->s_mode = mode; | |
146 | sd->s_type = type; | |
147 | sd->s_dentry = dentry; | |
148 | if (dentry) { | |
149 | dentry->d_fsdata = configfs_get(sd); | |
150 | dentry->d_op = &configfs_dentry_ops; | |
151 | } | |
152 | ||
153 | return 0; | |
154 | } | |
155 | ||
156 | static int init_dir(struct inode * inode) | |
157 | { | |
158 | inode->i_op = &configfs_dir_inode_operations; | |
159 | inode->i_fop = &configfs_dir_operations; | |
160 | ||
161 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |
d8c76e6f | 162 | inc_nlink(inode); |
7063fbf2 JB |
163 | return 0; |
164 | } | |
165 | ||
ce8d2cdf | 166 | static int configfs_init_file(struct inode * inode) |
7063fbf2 JB |
167 | { |
168 | inode->i_size = PAGE_SIZE; | |
169 | inode->i_fop = &configfs_file_operations; | |
170 | return 0; | |
171 | } | |
172 | ||
173 | static int init_symlink(struct inode * inode) | |
174 | { | |
175 | inode->i_op = &configfs_symlink_inode_operations; | |
176 | return 0; | |
177 | } | |
178 | ||
179 | static int create_dir(struct config_item * k, struct dentry * p, | |
180 | struct dentry * d) | |
181 | { | |
182 | int error; | |
183 | umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; | |
184 | ||
b4c98f62 JB |
185 | error = configfs_dirent_exists(p->d_fsdata, d->d_name.name); |
186 | if (!error) | |
187 | error = configfs_make_dirent(p->d_fsdata, d, k, mode, | |
2a109f2a | 188 | CONFIGFS_DIR | CONFIGFS_USET_CREATING); |
7063fbf2 | 189 | if (!error) { |
3d0f89bb | 190 | error = configfs_create(d, mode, init_dir); |
7063fbf2 | 191 | if (!error) { |
d8c76e6f | 192 | inc_nlink(p->d_inode); |
7063fbf2 | 193 | (d)->d_op = &configfs_dentry_ops; |
3d0f89bb JB |
194 | } else { |
195 | struct configfs_dirent *sd = d->d_fsdata; | |
196 | if (sd) { | |
6f610764 | 197 | spin_lock(&configfs_dirent_lock); |
3d0f89bb | 198 | list_del_init(&sd->s_sibling); |
6f610764 | 199 | spin_unlock(&configfs_dirent_lock); |
3d0f89bb JB |
200 | configfs_put(sd); |
201 | } | |
7063fbf2 JB |
202 | } |
203 | } | |
204 | return error; | |
205 | } | |
206 | ||
207 | ||
208 | /** | |
209 | * configfs_create_dir - create a directory for an config_item. | |
210 | * @item: config_itemwe're creating directory for. | |
211 | * @dentry: config_item's dentry. | |
2a109f2a LR |
212 | * |
213 | * Note: user-created entries won't be allowed under this new directory | |
214 | * until it is validated by configfs_dir_set_ready() | |
7063fbf2 JB |
215 | */ |
216 | ||
217 | static int configfs_create_dir(struct config_item * item, struct dentry *dentry) | |
218 | { | |
219 | struct dentry * parent; | |
220 | int error = 0; | |
221 | ||
222 | BUG_ON(!item); | |
223 | ||
224 | if (item->ci_parent) | |
225 | parent = item->ci_parent->ci_dentry; | |
226 | else if (configfs_mount && configfs_mount->mnt_sb) | |
227 | parent = configfs_mount->mnt_sb->s_root; | |
228 | else | |
229 | return -EFAULT; | |
230 | ||
231 | error = create_dir(item,parent,dentry); | |
232 | if (!error) | |
233 | item->ci_dentry = dentry; | |
234 | return error; | |
235 | } | |
236 | ||
2a109f2a LR |
237 | /* |
238 | * Allow userspace to create new entries under a new directory created with | |
239 | * configfs_create_dir(), and under all of its chidlren directories recursively. | |
240 | * @sd configfs_dirent of the new directory to validate | |
241 | * | |
242 | * Caller must hold configfs_dirent_lock. | |
243 | */ | |
244 | static void configfs_dir_set_ready(struct configfs_dirent *sd) | |
245 | { | |
246 | struct configfs_dirent *child_sd; | |
247 | ||
248 | sd->s_type &= ~CONFIGFS_USET_CREATING; | |
249 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) | |
250 | if (child_sd->s_type & CONFIGFS_USET_CREATING) | |
251 | configfs_dir_set_ready(child_sd); | |
252 | } | |
253 | ||
254 | /* | |
255 | * Check that a directory does not belong to a directory hierarchy being | |
256 | * attached and not validated yet. | |
257 | * @sd configfs_dirent of the directory to check | |
258 | * | |
259 | * @return non-zero iff the directory was validated | |
260 | * | |
261 | * Note: takes configfs_dirent_lock, so the result may change from false to true | |
262 | * in two consecutive calls, but never from true to false. | |
263 | */ | |
264 | int configfs_dirent_is_ready(struct configfs_dirent *sd) | |
265 | { | |
266 | int ret; | |
267 | ||
268 | spin_lock(&configfs_dirent_lock); | |
269 | ret = !(sd->s_type & CONFIGFS_USET_CREATING); | |
270 | spin_unlock(&configfs_dirent_lock); | |
271 | ||
272 | return ret; | |
273 | } | |
274 | ||
7063fbf2 JB |
275 | int configfs_create_link(struct configfs_symlink *sl, |
276 | struct dentry *parent, | |
277 | struct dentry *dentry) | |
278 | { | |
279 | int err = 0; | |
280 | umode_t mode = S_IFLNK | S_IRWXUGO; | |
281 | ||
3d0f89bb JB |
282 | err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode, |
283 | CONFIGFS_ITEM_LINK); | |
7063fbf2 | 284 | if (!err) { |
3d0f89bb | 285 | err = configfs_create(dentry, mode, init_symlink); |
7063fbf2 JB |
286 | if (!err) |
287 | dentry->d_op = &configfs_dentry_ops; | |
3d0f89bb JB |
288 | else { |
289 | struct configfs_dirent *sd = dentry->d_fsdata; | |
290 | if (sd) { | |
6f610764 | 291 | spin_lock(&configfs_dirent_lock); |
3d0f89bb | 292 | list_del_init(&sd->s_sibling); |
6f610764 | 293 | spin_unlock(&configfs_dirent_lock); |
3d0f89bb JB |
294 | configfs_put(sd); |
295 | } | |
296 | } | |
7063fbf2 JB |
297 | } |
298 | return err; | |
299 | } | |
300 | ||
301 | static void remove_dir(struct dentry * d) | |
302 | { | |
303 | struct dentry * parent = dget(d->d_parent); | |
304 | struct configfs_dirent * sd; | |
305 | ||
306 | sd = d->d_fsdata; | |
6f610764 | 307 | spin_lock(&configfs_dirent_lock); |
e7515d06 | 308 | list_del_init(&sd->s_sibling); |
6f610764 | 309 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
310 | configfs_put(sd); |
311 | if (d->d_inode) | |
312 | simple_rmdir(parent->d_inode,d); | |
313 | ||
314 | pr_debug(" o %s removing done (%d)\n",d->d_name.name, | |
315 | atomic_read(&d->d_count)); | |
316 | ||
317 | dput(parent); | |
318 | } | |
319 | ||
320 | /** | |
321 | * configfs_remove_dir - remove an config_item's directory. | |
322 | * @item: config_item we're removing. | |
323 | * | |
324 | * The only thing special about this is that we remove any files in | |
325 | * the directory before we remove the directory, and we've inlined | |
326 | * what used to be configfs_rmdir() below, instead of calling separately. | |
2e2ce171 LR |
327 | * |
328 | * Caller holds the mutex of the item's inode | |
7063fbf2 JB |
329 | */ |
330 | ||
331 | static void configfs_remove_dir(struct config_item * item) | |
332 | { | |
333 | struct dentry * dentry = dget(item->ci_dentry); | |
334 | ||
335 | if (!dentry) | |
336 | return; | |
337 | ||
338 | remove_dir(dentry); | |
339 | /** | |
340 | * Drop reference from dget() on entrance. | |
341 | */ | |
342 | dput(dentry); | |
343 | } | |
344 | ||
345 | ||
346 | /* attaches attribute's configfs_dirent to the dentry corresponding to the | |
347 | * attribute file | |
348 | */ | |
349 | static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry) | |
350 | { | |
351 | struct configfs_attribute * attr = sd->s_element; | |
352 | int error; | |
353 | ||
3d0f89bb JB |
354 | dentry->d_fsdata = configfs_get(sd); |
355 | sd->s_dentry = dentry; | |
ce8d2cdf DH |
356 | error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG, |
357 | configfs_init_file); | |
3d0f89bb JB |
358 | if (error) { |
359 | configfs_put(sd); | |
7063fbf2 | 360 | return error; |
3d0f89bb | 361 | } |
7063fbf2 JB |
362 | |
363 | dentry->d_op = &configfs_dentry_ops; | |
7063fbf2 JB |
364 | d_rehash(dentry); |
365 | ||
366 | return 0; | |
367 | } | |
368 | ||
369 | static struct dentry * configfs_lookup(struct inode *dir, | |
370 | struct dentry *dentry, | |
371 | struct nameidata *nd) | |
372 | { | |
373 | struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata; | |
374 | struct configfs_dirent * sd; | |
375 | int found = 0; | |
2a109f2a LR |
376 | int err; |
377 | ||
378 | /* | |
379 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
380 | * being attached | |
381 | * | |
382 | * This forbids userspace to read/write attributes of items which may | |
383 | * not complete their initialization, since the dentries of the | |
384 | * attributes won't be instantiated. | |
385 | */ | |
386 | err = -ENOENT; | |
387 | if (!configfs_dirent_is_ready(parent_sd)) | |
388 | goto out; | |
7063fbf2 JB |
389 | |
390 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
391 | if (sd->s_type & CONFIGFS_NOT_PINNED) { | |
392 | const unsigned char * name = configfs_get_name(sd); | |
393 | ||
394 | if (strcmp(name, dentry->d_name.name)) | |
395 | continue; | |
396 | ||
397 | found = 1; | |
398 | err = configfs_attach_attr(sd, dentry); | |
399 | break; | |
400 | } | |
401 | } | |
402 | ||
403 | if (!found) { | |
404 | /* | |
405 | * If it doesn't exist and it isn't a NOT_PINNED item, | |
406 | * it must be negative. | |
407 | */ | |
408 | return simple_lookup(dir, dentry, nd); | |
409 | } | |
410 | ||
2a109f2a | 411 | out: |
7063fbf2 JB |
412 | return ERR_PTR(err); |
413 | } | |
414 | ||
415 | /* | |
416 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are | |
b3e76af8 LR |
417 | * attributes and are removed by rmdir(). We recurse, setting |
418 | * CONFIGFS_USET_DROPPING on all children that are candidates for | |
419 | * default detach. | |
420 | * If there is an error, the caller will reset the flags via | |
421 | * configfs_detach_rollback(). | |
7063fbf2 | 422 | */ |
6d8344ba | 423 | static int configfs_detach_prep(struct dentry *dentry, struct mutex **wait_mutex) |
7063fbf2 JB |
424 | { |
425 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
426 | struct configfs_dirent *sd; | |
427 | int ret; | |
428 | ||
4768e9b1 LR |
429 | /* Mark that we're trying to drop the group */ |
430 | parent_sd->s_type |= CONFIGFS_USET_DROPPING; | |
431 | ||
7063fbf2 JB |
432 | ret = -EBUSY; |
433 | if (!list_empty(&parent_sd->s_links)) | |
434 | goto out; | |
435 | ||
436 | ret = 0; | |
437 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
99cefda4 LR |
438 | if (!sd->s_element || |
439 | (sd->s_type & CONFIGFS_NOT_PINNED)) | |
7063fbf2 JB |
440 | continue; |
441 | if (sd->s_type & CONFIGFS_USET_DEFAULT) { | |
6d8344ba LR |
442 | /* Abort if racing with mkdir() */ |
443 | if (sd->s_type & CONFIGFS_USET_IN_MKDIR) { | |
444 | if (wait_mutex) | |
445 | *wait_mutex = &sd->s_dentry->d_inode->i_mutex; | |
446 | return -EAGAIN; | |
447 | } | |
7063fbf2 | 448 | |
631d1feb JB |
449 | /* |
450 | * Yup, recursive. If there's a problem, blame | |
451 | * deep nesting of default_groups | |
452 | */ | |
6d8344ba | 453 | ret = configfs_detach_prep(sd->s_dentry, wait_mutex); |
7063fbf2 | 454 | if (!ret) |
e7515d06 | 455 | continue; |
7063fbf2 JB |
456 | } else |
457 | ret = -ENOTEMPTY; | |
458 | ||
459 | break; | |
460 | } | |
461 | ||
462 | out: | |
463 | return ret; | |
464 | } | |
465 | ||
466 | /* | |
b3e76af8 | 467 | * Walk the tree, resetting CONFIGFS_USET_DROPPING wherever it was |
7063fbf2 JB |
468 | * set. |
469 | */ | |
470 | static void configfs_detach_rollback(struct dentry *dentry) | |
471 | { | |
472 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
473 | struct configfs_dirent *sd; | |
474 | ||
4768e9b1 LR |
475 | parent_sd->s_type &= ~CONFIGFS_USET_DROPPING; |
476 | ||
477 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) | |
478 | if (sd->s_type & CONFIGFS_USET_DEFAULT) | |
7063fbf2 | 479 | configfs_detach_rollback(sd->s_dentry); |
7063fbf2 JB |
480 | } |
481 | ||
482 | static void detach_attrs(struct config_item * item) | |
483 | { | |
484 | struct dentry * dentry = dget(item->ci_dentry); | |
485 | struct configfs_dirent * parent_sd; | |
486 | struct configfs_dirent * sd, * tmp; | |
487 | ||
488 | if (!dentry) | |
489 | return; | |
490 | ||
491 | pr_debug("configfs %s: dropping attrs for dir\n", | |
492 | dentry->d_name.name); | |
493 | ||
494 | parent_sd = dentry->d_fsdata; | |
495 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
496 | if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED)) | |
497 | continue; | |
6f610764 | 498 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 499 | list_del_init(&sd->s_sibling); |
6f610764 | 500 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
501 | configfs_drop_dentry(sd, dentry); |
502 | configfs_put(sd); | |
503 | } | |
504 | ||
505 | /** | |
506 | * Drop reference from dget() on entrance. | |
507 | */ | |
508 | dput(dentry); | |
509 | } | |
510 | ||
511 | static int populate_attrs(struct config_item *item) | |
512 | { | |
513 | struct config_item_type *t = item->ci_type; | |
514 | struct configfs_attribute *attr; | |
515 | int error = 0; | |
516 | int i; | |
517 | ||
518 | if (!t) | |
519 | return -EINVAL; | |
520 | if (t->ct_attrs) { | |
521 | for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) { | |
522 | if ((error = configfs_create_file(item, attr))) | |
523 | break; | |
524 | } | |
525 | } | |
526 | ||
527 | if (error) | |
528 | detach_attrs(item); | |
529 | ||
530 | return error; | |
531 | } | |
532 | ||
533 | static int configfs_attach_group(struct config_item *parent_item, | |
534 | struct config_item *item, | |
535 | struct dentry *dentry); | |
536 | static void configfs_detach_group(struct config_item *item); | |
537 | ||
538 | static void detach_groups(struct config_group *group) | |
539 | { | |
540 | struct dentry * dentry = dget(group->cg_item.ci_dentry); | |
541 | struct dentry *child; | |
542 | struct configfs_dirent *parent_sd; | |
543 | struct configfs_dirent *sd, *tmp; | |
544 | ||
545 | if (!dentry) | |
546 | return; | |
547 | ||
548 | parent_sd = dentry->d_fsdata; | |
549 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
550 | if (!sd->s_element || | |
551 | !(sd->s_type & CONFIGFS_USET_DEFAULT)) | |
552 | continue; | |
553 | ||
554 | child = sd->s_dentry; | |
555 | ||
b3e76af8 LR |
556 | mutex_lock(&child->d_inode->i_mutex); |
557 | ||
7063fbf2 JB |
558 | configfs_detach_group(sd->s_element); |
559 | child->d_inode->i_flags |= S_DEAD; | |
560 | ||
b3e76af8 | 561 | mutex_unlock(&child->d_inode->i_mutex); |
7063fbf2 JB |
562 | |
563 | d_delete(child); | |
564 | dput(child); | |
565 | } | |
566 | ||
567 | /** | |
568 | * Drop reference from dget() on entrance. | |
569 | */ | |
570 | dput(dentry); | |
571 | } | |
572 | ||
573 | /* | |
574 | * This fakes mkdir(2) on a default_groups[] entry. It | |
575 | * creates a dentry, attachs it, and then does fixup | |
576 | * on the sd->s_type. | |
577 | * | |
578 | * We could, perhaps, tweak our parent's ->mkdir for a minute and | |
579 | * try using vfs_mkdir. Just a thought. | |
580 | */ | |
581 | static int create_default_group(struct config_group *parent_group, | |
582 | struct config_group *group) | |
583 | { | |
584 | int ret; | |
585 | struct qstr name; | |
586 | struct configfs_dirent *sd; | |
587 | /* We trust the caller holds a reference to parent */ | |
588 | struct dentry *child, *parent = parent_group->cg_item.ci_dentry; | |
589 | ||
590 | if (!group->cg_item.ci_name) | |
591 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
592 | name.name = group->cg_item.ci_name; | |
593 | name.len = strlen(name.name); | |
594 | name.hash = full_name_hash(name.name, name.len); | |
595 | ||
596 | ret = -ENOMEM; | |
597 | child = d_alloc(parent, &name); | |
598 | if (child) { | |
599 | d_add(child, NULL); | |
600 | ||
601 | ret = configfs_attach_group(&parent_group->cg_item, | |
602 | &group->cg_item, child); | |
603 | if (!ret) { | |
604 | sd = child->d_fsdata; | |
605 | sd->s_type |= CONFIGFS_USET_DEFAULT; | |
606 | } else { | |
607 | d_delete(child); | |
608 | dput(child); | |
609 | } | |
610 | } | |
611 | ||
612 | return ret; | |
613 | } | |
614 | ||
615 | static int populate_groups(struct config_group *group) | |
616 | { | |
617 | struct config_group *new_group; | |
7063fbf2 JB |
618 | int ret = 0; |
619 | int i; | |
620 | ||
cbca692c | 621 | if (group->default_groups) { |
7063fbf2 JB |
622 | for (i = 0; group->default_groups[i]; i++) { |
623 | new_group = group->default_groups[i]; | |
624 | ||
625 | ret = create_default_group(group, new_group); | |
2e2ce171 LR |
626 | if (ret) { |
627 | detach_groups(group); | |
7063fbf2 | 628 | break; |
2e2ce171 | 629 | } |
7063fbf2 | 630 | } |
7063fbf2 JB |
631 | } |
632 | ||
7063fbf2 JB |
633 | return ret; |
634 | } | |
635 | ||
636 | /* | |
637 | * All of link_obj/unlink_obj/link_group/unlink_group require that | |
e6bd07ae | 638 | * subsys->su_mutex is held. |
7063fbf2 JB |
639 | */ |
640 | ||
641 | static void unlink_obj(struct config_item *item) | |
642 | { | |
643 | struct config_group *group; | |
644 | ||
645 | group = item->ci_group; | |
646 | if (group) { | |
647 | list_del_init(&item->ci_entry); | |
648 | ||
649 | item->ci_group = NULL; | |
650 | item->ci_parent = NULL; | |
eed7a0db JB |
651 | |
652 | /* Drop the reference for ci_entry */ | |
7063fbf2 JB |
653 | config_item_put(item); |
654 | ||
eed7a0db | 655 | /* Drop the reference for ci_parent */ |
7063fbf2 JB |
656 | config_group_put(group); |
657 | } | |
658 | } | |
659 | ||
660 | static void link_obj(struct config_item *parent_item, struct config_item *item) | |
661 | { | |
eed7a0db JB |
662 | /* |
663 | * Parent seems redundant with group, but it makes certain | |
664 | * traversals much nicer. | |
665 | */ | |
7063fbf2 | 666 | item->ci_parent = parent_item; |
eed7a0db JB |
667 | |
668 | /* | |
669 | * We hold a reference on the parent for the child's ci_parent | |
670 | * link. | |
671 | */ | |
7063fbf2 JB |
672 | item->ci_group = config_group_get(to_config_group(parent_item)); |
673 | list_add_tail(&item->ci_entry, &item->ci_group->cg_children); | |
674 | ||
eed7a0db JB |
675 | /* |
676 | * We hold a reference on the child for ci_entry on the parent's | |
677 | * cg_children | |
678 | */ | |
7063fbf2 JB |
679 | config_item_get(item); |
680 | } | |
681 | ||
682 | static void unlink_group(struct config_group *group) | |
683 | { | |
684 | int i; | |
685 | struct config_group *new_group; | |
686 | ||
687 | if (group->default_groups) { | |
688 | for (i = 0; group->default_groups[i]; i++) { | |
689 | new_group = group->default_groups[i]; | |
690 | unlink_group(new_group); | |
691 | } | |
692 | } | |
693 | ||
694 | group->cg_subsys = NULL; | |
695 | unlink_obj(&group->cg_item); | |
696 | } | |
697 | ||
698 | static void link_group(struct config_group *parent_group, struct config_group *group) | |
699 | { | |
700 | int i; | |
701 | struct config_group *new_group; | |
702 | struct configfs_subsystem *subsys = NULL; /* gcc is a turd */ | |
703 | ||
704 | link_obj(&parent_group->cg_item, &group->cg_item); | |
705 | ||
706 | if (parent_group->cg_subsys) | |
707 | subsys = parent_group->cg_subsys; | |
708 | else if (configfs_is_root(&parent_group->cg_item)) | |
709 | subsys = to_configfs_subsystem(group); | |
710 | else | |
711 | BUG(); | |
712 | group->cg_subsys = subsys; | |
713 | ||
714 | if (group->default_groups) { | |
715 | for (i = 0; group->default_groups[i]; i++) { | |
716 | new_group = group->default_groups[i]; | |
717 | link_group(group, new_group); | |
718 | } | |
719 | } | |
720 | } | |
721 | ||
722 | /* | |
723 | * The goal is that configfs_attach_item() (and | |
724 | * configfs_attach_group()) can be called from either the VFS or this | |
725 | * module. That is, they assume that the items have been created, | |
726 | * the dentry allocated, and the dcache is all ready to go. | |
727 | * | |
728 | * If they fail, they must clean up after themselves as if they | |
729 | * had never been called. The caller (VFS or local function) will | |
730 | * handle cleaning up the dcache bits. | |
731 | * | |
732 | * configfs_detach_group() and configfs_detach_item() behave similarly on | |
733 | * the way out. They assume that the proper semaphores are held, they | |
734 | * clean up the configfs items, and they expect their callers will | |
735 | * handle the dcache bits. | |
736 | */ | |
737 | static int configfs_attach_item(struct config_item *parent_item, | |
738 | struct config_item *item, | |
739 | struct dentry *dentry) | |
740 | { | |
741 | int ret; | |
742 | ||
743 | ret = configfs_create_dir(item, dentry); | |
744 | if (!ret) { | |
745 | ret = populate_attrs(item); | |
746 | if (ret) { | |
2e2ce171 LR |
747 | /* |
748 | * We are going to remove an inode and its dentry but | |
749 | * the VFS may already have hit and used them. Thus, | |
750 | * we must lock them as rmdir() would. | |
751 | */ | |
752 | mutex_lock(&dentry->d_inode->i_mutex); | |
7063fbf2 | 753 | configfs_remove_dir(item); |
2e2ce171 LR |
754 | dentry->d_inode->i_flags |= S_DEAD; |
755 | mutex_unlock(&dentry->d_inode->i_mutex); | |
7063fbf2 JB |
756 | d_delete(dentry); |
757 | } | |
758 | } | |
759 | ||
760 | return ret; | |
761 | } | |
762 | ||
2e2ce171 | 763 | /* Caller holds the mutex of the item's inode */ |
7063fbf2 JB |
764 | static void configfs_detach_item(struct config_item *item) |
765 | { | |
766 | detach_attrs(item); | |
767 | configfs_remove_dir(item); | |
768 | } | |
769 | ||
770 | static int configfs_attach_group(struct config_item *parent_item, | |
771 | struct config_item *item, | |
772 | struct dentry *dentry) | |
773 | { | |
774 | int ret; | |
775 | struct configfs_dirent *sd; | |
776 | ||
777 | ret = configfs_attach_item(parent_item, item, dentry); | |
778 | if (!ret) { | |
779 | sd = dentry->d_fsdata; | |
780 | sd->s_type |= CONFIGFS_USET_DIR; | |
781 | ||
2e2ce171 LR |
782 | /* |
783 | * FYI, we're faking mkdir in populate_groups() | |
784 | * We must lock the group's inode to avoid races with the VFS | |
785 | * which can already hit the inode and try to add/remove entries | |
786 | * under it. | |
787 | * | |
788 | * We must also lock the inode to remove it safely in case of | |
789 | * error, as rmdir() would. | |
790 | */ | |
791 | mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); | |
7063fbf2 JB |
792 | ret = populate_groups(to_config_group(item)); |
793 | if (ret) { | |
794 | configfs_detach_item(item); | |
2e2ce171 | 795 | dentry->d_inode->i_flags |= S_DEAD; |
7063fbf2 | 796 | } |
2e2ce171 LR |
797 | mutex_unlock(&dentry->d_inode->i_mutex); |
798 | if (ret) | |
799 | d_delete(dentry); | |
7063fbf2 JB |
800 | } |
801 | ||
802 | return ret; | |
803 | } | |
804 | ||
2e2ce171 | 805 | /* Caller holds the mutex of the group's inode */ |
7063fbf2 JB |
806 | static void configfs_detach_group(struct config_item *item) |
807 | { | |
808 | detach_groups(to_config_group(item)); | |
809 | configfs_detach_item(item); | |
810 | } | |
811 | ||
299894cc JB |
812 | /* |
813 | * After the item has been detached from the filesystem view, we are | |
814 | * ready to tear it out of the hierarchy. Notify the client before | |
815 | * we do that so they can perform any cleanup that requires | |
816 | * navigating the hierarchy. A client does not need to provide this | |
817 | * callback. The subsystem semaphore MUST be held by the caller, and | |
818 | * references must be valid for both items. It also assumes the | |
819 | * caller has validated ci_type. | |
820 | */ | |
821 | static void client_disconnect_notify(struct config_item *parent_item, | |
822 | struct config_item *item) | |
823 | { | |
824 | struct config_item_type *type; | |
825 | ||
826 | type = parent_item->ci_type; | |
827 | BUG_ON(!type); | |
828 | ||
829 | if (type->ct_group_ops && type->ct_group_ops->disconnect_notify) | |
830 | type->ct_group_ops->disconnect_notify(to_config_group(parent_item), | |
831 | item); | |
832 | } | |
833 | ||
7063fbf2 JB |
834 | /* |
835 | * Drop the initial reference from make_item()/make_group() | |
836 | * This function assumes that reference is held on item | |
837 | * and that item holds a valid reference to the parent. Also, it | |
838 | * assumes the caller has validated ci_type. | |
839 | */ | |
840 | static void client_drop_item(struct config_item *parent_item, | |
841 | struct config_item *item) | |
842 | { | |
843 | struct config_item_type *type; | |
844 | ||
845 | type = parent_item->ci_type; | |
846 | BUG_ON(!type); | |
847 | ||
eed7a0db JB |
848 | /* |
849 | * If ->drop_item() exists, it is responsible for the | |
850 | * config_item_put(). | |
851 | */ | |
7063fbf2 JB |
852 | if (type->ct_group_ops && type->ct_group_ops->drop_item) |
853 | type->ct_group_ops->drop_item(to_config_group(parent_item), | |
299894cc | 854 | item); |
7063fbf2 JB |
855 | else |
856 | config_item_put(item); | |
857 | } | |
858 | ||
631d1feb JB |
859 | #ifdef DEBUG |
860 | static void configfs_dump_one(struct configfs_dirent *sd, int level) | |
861 | { | |
862 | printk(KERN_INFO "%*s\"%s\":\n", level, " ", configfs_get_name(sd)); | |
863 | ||
864 | #define type_print(_type) if (sd->s_type & _type) printk(KERN_INFO "%*s %s\n", level, " ", #_type); | |
865 | type_print(CONFIGFS_ROOT); | |
866 | type_print(CONFIGFS_DIR); | |
867 | type_print(CONFIGFS_ITEM_ATTR); | |
868 | type_print(CONFIGFS_ITEM_LINK); | |
869 | type_print(CONFIGFS_USET_DIR); | |
870 | type_print(CONFIGFS_USET_DEFAULT); | |
871 | type_print(CONFIGFS_USET_DROPPING); | |
872 | #undef type_print | |
873 | } | |
874 | ||
875 | static int configfs_dump(struct configfs_dirent *sd, int level) | |
876 | { | |
877 | struct configfs_dirent *child_sd; | |
878 | int ret = 0; | |
879 | ||
880 | configfs_dump_one(sd, level); | |
881 | ||
882 | if (!(sd->s_type & (CONFIGFS_DIR|CONFIGFS_ROOT))) | |
883 | return 0; | |
884 | ||
885 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) { | |
886 | ret = configfs_dump(child_sd, level + 2); | |
887 | if (ret) | |
888 | break; | |
889 | } | |
890 | ||
891 | return ret; | |
892 | } | |
893 | #endif | |
894 | ||
895 | ||
896 | /* | |
897 | * configfs_depend_item() and configfs_undepend_item() | |
898 | * | |
899 | * WARNING: Do not call these from a configfs callback! | |
900 | * | |
901 | * This describes these functions and their helpers. | |
902 | * | |
903 | * Allow another kernel system to depend on a config_item. If this | |
904 | * happens, the item cannot go away until the dependant can live without | |
905 | * it. The idea is to give client modules as simple an interface as | |
906 | * possible. When a system asks them to depend on an item, they just | |
907 | * call configfs_depend_item(). If the item is live and the client | |
908 | * driver is in good shape, we'll happily do the work for them. | |
909 | * | |
910 | * Why is the locking complex? Because configfs uses the VFS to handle | |
911 | * all locking, but this function is called outside the normal | |
912 | * VFS->configfs path. So it must take VFS locks to prevent the | |
913 | * VFS->configfs stuff (configfs_mkdir(), configfs_rmdir(), etc). This is | |
914 | * why you can't call these functions underneath configfs callbacks. | |
915 | * | |
916 | * Note, btw, that this can be called at *any* time, even when a configfs | |
917 | * subsystem isn't registered, or when configfs is loading or unloading. | |
918 | * Just like configfs_register_subsystem(). So we take the same | |
919 | * precautions. We pin the filesystem. We lock each i_mutex _in_order_ | |
920 | * on our way down the tree. If we can find the target item in the | |
921 | * configfs tree, it must be part of the subsystem tree as well, so we | |
922 | * do not need the subsystem semaphore. Holding the i_mutex chain locks | |
923 | * out mkdir() and rmdir(), who might be racing us. | |
924 | */ | |
925 | ||
926 | /* | |
927 | * configfs_depend_prep() | |
928 | * | |
929 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are | |
930 | * attributes. This is similar but not the same to configfs_detach_prep(). | |
931 | * Note that configfs_detach_prep() expects the parent to be locked when it | |
932 | * is called, but we lock the parent *inside* configfs_depend_prep(). We | |
933 | * do that so we can unlock it if we find nothing. | |
934 | * | |
935 | * Here we do a depth-first search of the dentry hierarchy looking for | |
936 | * our object. We take i_mutex on each step of the way down. IT IS | |
937 | * ESSENTIAL THAT i_mutex LOCKING IS ORDERED. If we come back up a branch, | |
938 | * we'll drop the i_mutex. | |
939 | * | |
940 | * If the target is not found, -ENOENT is bubbled up and we have released | |
941 | * all locks. If the target was found, the locks will be cleared by | |
942 | * configfs_depend_rollback(). | |
943 | * | |
944 | * This adds a requirement that all config_items be unique! | |
945 | * | |
946 | * This is recursive because the locking traversal is tricky. There isn't | |
947 | * much on the stack, though, so folks that need this function - be careful | |
948 | * about your stack! Patches will be accepted to make it iterative. | |
949 | */ | |
950 | static int configfs_depend_prep(struct dentry *origin, | |
951 | struct config_item *target) | |
952 | { | |
953 | struct configfs_dirent *child_sd, *sd = origin->d_fsdata; | |
954 | int ret = 0; | |
955 | ||
956 | BUG_ON(!origin || !sd); | |
957 | ||
958 | /* Lock this guy on the way down */ | |
959 | mutex_lock(&sd->s_dentry->d_inode->i_mutex); | |
960 | if (sd->s_element == target) /* Boo-yah */ | |
961 | goto out; | |
962 | ||
963 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) { | |
964 | if (child_sd->s_type & CONFIGFS_DIR) { | |
965 | ret = configfs_depend_prep(child_sd->s_dentry, | |
966 | target); | |
967 | if (!ret) | |
968 | goto out; /* Child path boo-yah */ | |
969 | } | |
970 | } | |
971 | ||
972 | /* We looped all our children and didn't find target */ | |
973 | mutex_unlock(&sd->s_dentry->d_inode->i_mutex); | |
974 | ret = -ENOENT; | |
975 | ||
976 | out: | |
977 | return ret; | |
978 | } | |
979 | ||
980 | /* | |
981 | * This is ONLY called if configfs_depend_prep() did its job. So we can | |
982 | * trust the entire path from item back up to origin. | |
983 | * | |
984 | * We walk backwards from item, unlocking each i_mutex. We finish by | |
985 | * unlocking origin. | |
986 | */ | |
987 | static void configfs_depend_rollback(struct dentry *origin, | |
988 | struct config_item *item) | |
989 | { | |
990 | struct dentry *dentry = item->ci_dentry; | |
991 | ||
992 | while (dentry != origin) { | |
993 | mutex_unlock(&dentry->d_inode->i_mutex); | |
994 | dentry = dentry->d_parent; | |
995 | } | |
996 | ||
997 | mutex_unlock(&origin->d_inode->i_mutex); | |
998 | } | |
999 | ||
1000 | int configfs_depend_item(struct configfs_subsystem *subsys, | |
1001 | struct config_item *target) | |
1002 | { | |
1003 | int ret; | |
1004 | struct configfs_dirent *p, *root_sd, *subsys_sd = NULL; | |
1005 | struct config_item *s_item = &subsys->su_group.cg_item; | |
1006 | ||
1007 | /* | |
1008 | * Pin the configfs filesystem. This means we can safely access | |
1009 | * the root of the configfs filesystem. | |
1010 | */ | |
1011 | ret = configfs_pin_fs(); | |
1012 | if (ret) | |
1013 | return ret; | |
1014 | ||
1015 | /* | |
1016 | * Next, lock the root directory. We're going to check that the | |
1017 | * subsystem is really registered, and so we need to lock out | |
1018 | * configfs_[un]register_subsystem(). | |
1019 | */ | |
1020 | mutex_lock(&configfs_sb->s_root->d_inode->i_mutex); | |
1021 | ||
1022 | root_sd = configfs_sb->s_root->d_fsdata; | |
1023 | ||
1024 | list_for_each_entry(p, &root_sd->s_children, s_sibling) { | |
1025 | if (p->s_type & CONFIGFS_DIR) { | |
1026 | if (p->s_element == s_item) { | |
1027 | subsys_sd = p; | |
1028 | break; | |
1029 | } | |
1030 | } | |
1031 | } | |
1032 | ||
1033 | if (!subsys_sd) { | |
1034 | ret = -ENOENT; | |
1035 | goto out_unlock_fs; | |
1036 | } | |
1037 | ||
1038 | /* Ok, now we can trust subsys/s_item */ | |
1039 | ||
1040 | /* Scan the tree, locking i_mutex recursively, return 0 if found */ | |
1041 | ret = configfs_depend_prep(subsys_sd->s_dentry, target); | |
1042 | if (ret) | |
1043 | goto out_unlock_fs; | |
1044 | ||
1045 | /* We hold all i_mutexes from the subsystem down to the target */ | |
1046 | p = target->ci_dentry->d_fsdata; | |
1047 | p->s_dependent_count += 1; | |
1048 | ||
1049 | configfs_depend_rollback(subsys_sd->s_dentry, target); | |
1050 | ||
1051 | out_unlock_fs: | |
1052 | mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex); | |
1053 | ||
1054 | /* | |
1055 | * If we succeeded, the fs is pinned via other methods. If not, | |
1056 | * we're done with it anyway. So release_fs() is always right. | |
1057 | */ | |
1058 | configfs_release_fs(); | |
1059 | ||
1060 | return ret; | |
1061 | } | |
1062 | EXPORT_SYMBOL(configfs_depend_item); | |
1063 | ||
1064 | /* | |
1065 | * Release the dependent linkage. This is much simpler than | |
1066 | * configfs_depend_item() because we know that that the client driver is | |
1067 | * pinned, thus the subsystem is pinned, and therefore configfs is pinned. | |
1068 | */ | |
1069 | void configfs_undepend_item(struct configfs_subsystem *subsys, | |
1070 | struct config_item *target) | |
1071 | { | |
1072 | struct configfs_dirent *sd; | |
1073 | ||
1074 | /* | |
1075 | * Since we can trust everything is pinned, we just need i_mutex | |
1076 | * on the item. | |
1077 | */ | |
1078 | mutex_lock(&target->ci_dentry->d_inode->i_mutex); | |
1079 | ||
1080 | sd = target->ci_dentry->d_fsdata; | |
1081 | BUG_ON(sd->s_dependent_count < 1); | |
1082 | ||
1083 | sd->s_dependent_count -= 1; | |
1084 | ||
1085 | /* | |
1086 | * After this unlock, we cannot trust the item to stay alive! | |
1087 | * DO NOT REFERENCE item after this unlock. | |
1088 | */ | |
1089 | mutex_unlock(&target->ci_dentry->d_inode->i_mutex); | |
1090 | } | |
1091 | EXPORT_SYMBOL(configfs_undepend_item); | |
7063fbf2 JB |
1092 | |
1093 | static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
1094 | { | |
a6795e9e JB |
1095 | int ret = 0; |
1096 | int module_got = 0; | |
1097 | struct config_group *group = NULL; | |
1098 | struct config_item *item = NULL; | |
7063fbf2 JB |
1099 | struct config_item *parent_item; |
1100 | struct configfs_subsystem *subsys; | |
1101 | struct configfs_dirent *sd; | |
1102 | struct config_item_type *type; | |
70526b67 | 1103 | struct module *subsys_owner = NULL, *new_item_owner = NULL; |
7063fbf2 JB |
1104 | char *name; |
1105 | ||
84efad1a JB |
1106 | if (dentry->d_parent == configfs_sb->s_root) { |
1107 | ret = -EPERM; | |
1108 | goto out; | |
1109 | } | |
7063fbf2 JB |
1110 | |
1111 | sd = dentry->d_parent->d_fsdata; | |
2a109f2a LR |
1112 | |
1113 | /* | |
1114 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
1115 | * being attached | |
1116 | */ | |
1117 | if (!configfs_dirent_is_ready(sd)) { | |
1118 | ret = -ENOENT; | |
1119 | goto out; | |
1120 | } | |
1121 | ||
84efad1a JB |
1122 | if (!(sd->s_type & CONFIGFS_USET_DIR)) { |
1123 | ret = -EPERM; | |
1124 | goto out; | |
1125 | } | |
7063fbf2 | 1126 | |
84efad1a | 1127 | /* Get a working ref for the duration of this function */ |
7063fbf2 JB |
1128 | parent_item = configfs_get_config_item(dentry->d_parent); |
1129 | type = parent_item->ci_type; | |
1130 | subsys = to_config_group(parent_item)->cg_subsys; | |
1131 | BUG_ON(!subsys); | |
1132 | ||
1133 | if (!type || !type->ct_group_ops || | |
1134 | (!type->ct_group_ops->make_group && | |
1135 | !type->ct_group_ops->make_item)) { | |
84efad1a JB |
1136 | ret = -EPERM; /* Lack-of-mkdir returns -EPERM */ |
1137 | goto out_put; | |
7063fbf2 JB |
1138 | } |
1139 | ||
70526b67 JB |
1140 | /* |
1141 | * The subsystem may belong to a different module than the item | |
1142 | * being created. We don't want to safely pin the new item but | |
1143 | * fail to pin the subsystem it sits under. | |
1144 | */ | |
1145 | if (!subsys->su_group.cg_item.ci_type) { | |
1146 | ret = -EINVAL; | |
1147 | goto out_put; | |
1148 | } | |
1149 | subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; | |
1150 | if (!try_module_get(subsys_owner)) { | |
1151 | ret = -EINVAL; | |
1152 | goto out_put; | |
1153 | } | |
1154 | ||
7063fbf2 JB |
1155 | name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL); |
1156 | if (!name) { | |
84efad1a | 1157 | ret = -ENOMEM; |
70526b67 | 1158 | goto out_subsys_put; |
7063fbf2 | 1159 | } |
84efad1a | 1160 | |
7063fbf2 JB |
1161 | snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name); |
1162 | ||
e6bd07ae | 1163 | mutex_lock(&subsys->su_mutex); |
7063fbf2 | 1164 | if (type->ct_group_ops->make_group) { |
f89ab861 | 1165 | group = type->ct_group_ops->make_group(to_config_group(parent_item), name); |
a6795e9e JB |
1166 | if (!group) |
1167 | group = ERR_PTR(-ENOMEM); | |
1168 | if (!IS_ERR(group)) { | |
7063fbf2 JB |
1169 | link_group(to_config_group(parent_item), group); |
1170 | item = &group->cg_item; | |
a6795e9e JB |
1171 | } else |
1172 | ret = PTR_ERR(group); | |
7063fbf2 | 1173 | } else { |
f89ab861 | 1174 | item = type->ct_group_ops->make_item(to_config_group(parent_item), name); |
a6795e9e JB |
1175 | if (!item) |
1176 | item = ERR_PTR(-ENOMEM); | |
1177 | if (!IS_ERR(item)) | |
7063fbf2 | 1178 | link_obj(parent_item, item); |
a6795e9e JB |
1179 | else |
1180 | ret = PTR_ERR(item); | |
7063fbf2 | 1181 | } |
e6bd07ae | 1182 | mutex_unlock(&subsys->su_mutex); |
7063fbf2 JB |
1183 | |
1184 | kfree(name); | |
a6795e9e | 1185 | if (ret) { |
eed7a0db | 1186 | /* |
dacdd0e0 | 1187 | * If ret != 0, then link_obj() was never called. |
eed7a0db JB |
1188 | * There are no extra references to clean up. |
1189 | */ | |
70526b67 | 1190 | goto out_subsys_put; |
7063fbf2 JB |
1191 | } |
1192 | ||
eed7a0db JB |
1193 | /* |
1194 | * link_obj() has been called (via link_group() for groups). | |
1195 | * From here on out, errors must clean that up. | |
1196 | */ | |
1197 | ||
7063fbf2 | 1198 | type = item->ci_type; |
eed7a0db JB |
1199 | if (!type) { |
1200 | ret = -EINVAL; | |
1201 | goto out_unlink; | |
1202 | } | |
7063fbf2 | 1203 | |
70526b67 JB |
1204 | new_item_owner = type->ct_owner; |
1205 | if (!try_module_get(new_item_owner)) { | |
eed7a0db JB |
1206 | ret = -EINVAL; |
1207 | goto out_unlink; | |
1208 | } | |
7063fbf2 | 1209 | |
eed7a0db JB |
1210 | /* |
1211 | * I hate doing it this way, but if there is | |
1212 | * an error, module_put() probably should | |
1213 | * happen after any cleanup. | |
1214 | */ | |
1215 | module_got = 1; | |
1216 | ||
6d8344ba LR |
1217 | /* |
1218 | * Make racing rmdir() fail if it did not tag parent with | |
1219 | * CONFIGFS_USET_DROPPING | |
1220 | * Note: if CONFIGFS_USET_DROPPING is already set, attach_group() will | |
1221 | * fail and let rmdir() terminate correctly | |
1222 | */ | |
1223 | spin_lock(&configfs_dirent_lock); | |
1224 | /* This will make configfs_detach_prep() fail */ | |
1225 | sd->s_type |= CONFIGFS_USET_IN_MKDIR; | |
1226 | spin_unlock(&configfs_dirent_lock); | |
1227 | ||
eed7a0db JB |
1228 | if (group) |
1229 | ret = configfs_attach_group(parent_item, item, dentry); | |
1230 | else | |
1231 | ret = configfs_attach_item(parent_item, item, dentry); | |
1232 | ||
6d8344ba LR |
1233 | spin_lock(&configfs_dirent_lock); |
1234 | sd->s_type &= ~CONFIGFS_USET_IN_MKDIR; | |
2a109f2a LR |
1235 | if (!ret) |
1236 | configfs_dir_set_ready(dentry->d_fsdata); | |
6d8344ba LR |
1237 | spin_unlock(&configfs_dirent_lock); |
1238 | ||
eed7a0db JB |
1239 | out_unlink: |
1240 | if (ret) { | |
1241 | /* Tear down everything we built up */ | |
e6bd07ae | 1242 | mutex_lock(&subsys->su_mutex); |
299894cc JB |
1243 | |
1244 | client_disconnect_notify(parent_item, item); | |
eed7a0db JB |
1245 | if (group) |
1246 | unlink_group(group); | |
1247 | else | |
1248 | unlink_obj(item); | |
1249 | client_drop_item(parent_item, item); | |
299894cc | 1250 | |
e6bd07ae | 1251 | mutex_unlock(&subsys->su_mutex); |
eed7a0db JB |
1252 | |
1253 | if (module_got) | |
70526b67 | 1254 | module_put(new_item_owner); |
7063fbf2 JB |
1255 | } |
1256 | ||
70526b67 JB |
1257 | out_subsys_put: |
1258 | if (ret) | |
1259 | module_put(subsys_owner); | |
1260 | ||
84efad1a JB |
1261 | out_put: |
1262 | /* | |
eed7a0db JB |
1263 | * link_obj()/link_group() took a reference from child->parent, |
1264 | * so the parent is safely pinned. We can drop our working | |
1265 | * reference. | |
84efad1a JB |
1266 | */ |
1267 | config_item_put(parent_item); | |
1268 | ||
1269 | out: | |
7063fbf2 JB |
1270 | return ret; |
1271 | } | |
1272 | ||
1273 | static int configfs_rmdir(struct inode *dir, struct dentry *dentry) | |
1274 | { | |
1275 | struct config_item *parent_item; | |
1276 | struct config_item *item; | |
1277 | struct configfs_subsystem *subsys; | |
1278 | struct configfs_dirent *sd; | |
70526b67 | 1279 | struct module *subsys_owner = NULL, *dead_item_owner = NULL; |
7063fbf2 JB |
1280 | int ret; |
1281 | ||
1282 | if (dentry->d_parent == configfs_sb->s_root) | |
1283 | return -EPERM; | |
1284 | ||
1285 | sd = dentry->d_fsdata; | |
1286 | if (sd->s_type & CONFIGFS_USET_DEFAULT) | |
1287 | return -EPERM; | |
1288 | ||
631d1feb JB |
1289 | /* |
1290 | * Here's where we check for dependents. We're protected by | |
1291 | * i_mutex. | |
1292 | */ | |
1293 | if (sd->s_dependent_count) | |
1294 | return -EBUSY; | |
1295 | ||
84efad1a | 1296 | /* Get a working ref until we have the child */ |
7063fbf2 JB |
1297 | parent_item = configfs_get_config_item(dentry->d_parent); |
1298 | subsys = to_config_group(parent_item)->cg_subsys; | |
1299 | BUG_ON(!subsys); | |
1300 | ||
1301 | if (!parent_item->ci_type) { | |
1302 | config_item_put(parent_item); | |
1303 | return -EINVAL; | |
1304 | } | |
1305 | ||
70526b67 JB |
1306 | /* configfs_mkdir() shouldn't have allowed this */ |
1307 | BUG_ON(!subsys->su_group.cg_item.ci_type); | |
1308 | subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; | |
1309 | ||
9a73d78c LR |
1310 | /* |
1311 | * Ensure that no racing symlink() will make detach_prep() fail while | |
1312 | * the new link is temporarily attached | |
1313 | */ | |
6d8344ba LR |
1314 | do { |
1315 | struct mutex *wait_mutex; | |
1316 | ||
de6bf18e LR |
1317 | mutex_lock(&configfs_symlink_mutex); |
1318 | spin_lock(&configfs_dirent_lock); | |
6d8344ba | 1319 | ret = configfs_detach_prep(dentry, &wait_mutex); |
de6bf18e | 1320 | if (ret) |
6d8344ba | 1321 | configfs_detach_rollback(dentry); |
de6bf18e LR |
1322 | spin_unlock(&configfs_dirent_lock); |
1323 | mutex_unlock(&configfs_symlink_mutex); | |
1324 | ||
1325 | if (ret) { | |
6d8344ba LR |
1326 | if (ret != -EAGAIN) { |
1327 | config_item_put(parent_item); | |
1328 | return ret; | |
1329 | } | |
1330 | ||
1331 | /* Wait until the racing operation terminates */ | |
1332 | mutex_lock(wait_mutex); | |
1333 | mutex_unlock(wait_mutex); | |
6d8344ba LR |
1334 | } |
1335 | } while (ret == -EAGAIN); | |
7063fbf2 | 1336 | |
84efad1a | 1337 | /* Get a working ref for the duration of this function */ |
7063fbf2 JB |
1338 | item = configfs_get_config_item(dentry); |
1339 | ||
1340 | /* Drop reference from above, item already holds one. */ | |
1341 | config_item_put(parent_item); | |
1342 | ||
1343 | if (item->ci_type) | |
70526b67 | 1344 | dead_item_owner = item->ci_type->ct_owner; |
7063fbf2 JB |
1345 | |
1346 | if (sd->s_type & CONFIGFS_USET_DIR) { | |
1347 | configfs_detach_group(item); | |
1348 | ||
e6bd07ae | 1349 | mutex_lock(&subsys->su_mutex); |
299894cc | 1350 | client_disconnect_notify(parent_item, item); |
7063fbf2 JB |
1351 | unlink_group(to_config_group(item)); |
1352 | } else { | |
1353 | configfs_detach_item(item); | |
1354 | ||
e6bd07ae | 1355 | mutex_lock(&subsys->su_mutex); |
299894cc | 1356 | client_disconnect_notify(parent_item, item); |
7063fbf2 JB |
1357 | unlink_obj(item); |
1358 | } | |
1359 | ||
1360 | client_drop_item(parent_item, item); | |
e6bd07ae | 1361 | mutex_unlock(&subsys->su_mutex); |
7063fbf2 JB |
1362 | |
1363 | /* Drop our reference from above */ | |
1364 | config_item_put(item); | |
1365 | ||
70526b67 JB |
1366 | module_put(dead_item_owner); |
1367 | module_put(subsys_owner); | |
7063fbf2 JB |
1368 | |
1369 | return 0; | |
1370 | } | |
1371 | ||
754661f1 | 1372 | const struct inode_operations configfs_dir_inode_operations = { |
7063fbf2 JB |
1373 | .mkdir = configfs_mkdir, |
1374 | .rmdir = configfs_rmdir, | |
1375 | .symlink = configfs_symlink, | |
1376 | .unlink = configfs_unlink, | |
1377 | .lookup = configfs_lookup, | |
3d0f89bb | 1378 | .setattr = configfs_setattr, |
7063fbf2 JB |
1379 | }; |
1380 | ||
1381 | #if 0 | |
1382 | int configfs_rename_dir(struct config_item * item, const char *new_name) | |
1383 | { | |
1384 | int error = 0; | |
1385 | struct dentry * new_dentry, * parent; | |
1386 | ||
1387 | if (!strcmp(config_item_name(item), new_name)) | |
1388 | return -EINVAL; | |
1389 | ||
1390 | if (!item->parent) | |
1391 | return -EINVAL; | |
1392 | ||
1393 | down_write(&configfs_rename_sem); | |
1394 | parent = item->parent->dentry; | |
1395 | ||
1b1dcc1b | 1396 | mutex_lock(&parent->d_inode->i_mutex); |
7063fbf2 JB |
1397 | |
1398 | new_dentry = lookup_one_len(new_name, parent, strlen(new_name)); | |
1399 | if (!IS_ERR(new_dentry)) { | |
e7515d06 | 1400 | if (!new_dentry->d_inode) { |
7063fbf2 JB |
1401 | error = config_item_set_name(item, "%s", new_name); |
1402 | if (!error) { | |
1403 | d_add(new_dentry, NULL); | |
1404 | d_move(item->dentry, new_dentry); | |
1405 | } | |
1406 | else | |
1407 | d_delete(new_dentry); | |
1408 | } else | |
1409 | error = -EEXIST; | |
1410 | dput(new_dentry); | |
1411 | } | |
1b1dcc1b | 1412 | mutex_unlock(&parent->d_inode->i_mutex); |
7063fbf2 JB |
1413 | up_write(&configfs_rename_sem); |
1414 | ||
1415 | return error; | |
1416 | } | |
1417 | #endif | |
1418 | ||
1419 | static int configfs_dir_open(struct inode *inode, struct file *file) | |
1420 | { | |
867fa491 | 1421 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 | 1422 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
2a109f2a | 1423 | int err; |
7063fbf2 | 1424 | |
1b1dcc1b | 1425 | mutex_lock(&dentry->d_inode->i_mutex); |
2a109f2a LR |
1426 | /* |
1427 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
1428 | * being attached | |
1429 | */ | |
1430 | err = -ENOENT; | |
1431 | if (configfs_dirent_is_ready(parent_sd)) { | |
1432 | file->private_data = configfs_new_dirent(parent_sd, NULL); | |
1433 | if (IS_ERR(file->private_data)) | |
1434 | err = PTR_ERR(file->private_data); | |
1435 | else | |
1436 | err = 0; | |
1437 | } | |
1b1dcc1b | 1438 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 | 1439 | |
2a109f2a | 1440 | return err; |
7063fbf2 JB |
1441 | } |
1442 | ||
1443 | static int configfs_dir_close(struct inode *inode, struct file *file) | |
1444 | { | |
867fa491 | 1445 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 JB |
1446 | struct configfs_dirent * cursor = file->private_data; |
1447 | ||
1b1dcc1b | 1448 | mutex_lock(&dentry->d_inode->i_mutex); |
6f610764 | 1449 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 1450 | list_del_init(&cursor->s_sibling); |
6f610764 | 1451 | spin_unlock(&configfs_dirent_lock); |
1b1dcc1b | 1452 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1453 | |
1454 | release_configfs_dirent(cursor); | |
1455 | ||
1456 | return 0; | |
1457 | } | |
1458 | ||
1459 | /* Relationship between s_mode and the DT_xxx types */ | |
1460 | static inline unsigned char dt_type(struct configfs_dirent *sd) | |
1461 | { | |
1462 | return (sd->s_mode >> 12) & 15; | |
1463 | } | |
1464 | ||
1465 | static int configfs_readdir(struct file * filp, void * dirent, filldir_t filldir) | |
1466 | { | |
867fa491 | 1467 | struct dentry *dentry = filp->f_path.dentry; |
7063fbf2 JB |
1468 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
1469 | struct configfs_dirent *cursor = filp->private_data; | |
1470 | struct list_head *p, *q = &cursor->s_sibling; | |
1471 | ino_t ino; | |
1472 | int i = filp->f_pos; | |
1473 | ||
1474 | switch (i) { | |
1475 | case 0: | |
1476 | ino = dentry->d_inode->i_ino; | |
1477 | if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) | |
1478 | break; | |
1479 | filp->f_pos++; | |
1480 | i++; | |
1481 | /* fallthrough */ | |
1482 | case 1: | |
1483 | ino = parent_ino(dentry); | |
1484 | if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) | |
1485 | break; | |
1486 | filp->f_pos++; | |
1487 | i++; | |
1488 | /* fallthrough */ | |
1489 | default: | |
1490 | if (filp->f_pos == 2) { | |
6f610764 | 1491 | spin_lock(&configfs_dirent_lock); |
f116629d | 1492 | list_move(q, &parent_sd->s_children); |
6f610764 | 1493 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
1494 | } |
1495 | for (p=q->next; p!= &parent_sd->s_children; p=p->next) { | |
1496 | struct configfs_dirent *next; | |
1497 | const char * name; | |
1498 | int len; | |
1499 | ||
1500 | next = list_entry(p, struct configfs_dirent, | |
1501 | s_sibling); | |
1502 | if (!next->s_element) | |
1503 | continue; | |
1504 | ||
1505 | name = configfs_get_name(next); | |
1506 | len = strlen(name); | |
1507 | if (next->s_dentry) | |
1508 | ino = next->s_dentry->d_inode->i_ino; | |
1509 | else | |
1510 | ino = iunique(configfs_sb, 2); | |
1511 | ||
1512 | if (filldir(dirent, name, len, filp->f_pos, ino, | |
1513 | dt_type(next)) < 0) | |
1514 | return 0; | |
1515 | ||
6f610764 | 1516 | spin_lock(&configfs_dirent_lock); |
f116629d | 1517 | list_move(q, p); |
6f610764 | 1518 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
1519 | p = q; |
1520 | filp->f_pos++; | |
1521 | } | |
1522 | } | |
1523 | return 0; | |
1524 | } | |
1525 | ||
1526 | static loff_t configfs_dir_lseek(struct file * file, loff_t offset, int origin) | |
1527 | { | |
867fa491 | 1528 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 | 1529 | |
1b1dcc1b | 1530 | mutex_lock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1531 | switch (origin) { |
1532 | case 1: | |
1533 | offset += file->f_pos; | |
1534 | case 0: | |
1535 | if (offset >= 0) | |
1536 | break; | |
1537 | default: | |
867fa491 | 1538 | mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); |
7063fbf2 JB |
1539 | return -EINVAL; |
1540 | } | |
1541 | if (offset != file->f_pos) { | |
1542 | file->f_pos = offset; | |
1543 | if (file->f_pos >= 2) { | |
1544 | struct configfs_dirent *sd = dentry->d_fsdata; | |
1545 | struct configfs_dirent *cursor = file->private_data; | |
1546 | struct list_head *p; | |
1547 | loff_t n = file->f_pos - 2; | |
1548 | ||
6f610764 | 1549 | spin_lock(&configfs_dirent_lock); |
7063fbf2 JB |
1550 | list_del(&cursor->s_sibling); |
1551 | p = sd->s_children.next; | |
1552 | while (n && p != &sd->s_children) { | |
1553 | struct configfs_dirent *next; | |
1554 | next = list_entry(p, struct configfs_dirent, | |
1555 | s_sibling); | |
1556 | if (next->s_element) | |
1557 | n--; | |
1558 | p = p->next; | |
1559 | } | |
1560 | list_add_tail(&cursor->s_sibling, p); | |
6f610764 | 1561 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
1562 | } |
1563 | } | |
1b1dcc1b | 1564 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1565 | return offset; |
1566 | } | |
1567 | ||
4b6f5d20 | 1568 | const struct file_operations configfs_dir_operations = { |
7063fbf2 JB |
1569 | .open = configfs_dir_open, |
1570 | .release = configfs_dir_close, | |
1571 | .llseek = configfs_dir_lseek, | |
1572 | .read = generic_read_dir, | |
1573 | .readdir = configfs_readdir, | |
1574 | }; | |
1575 | ||
1576 | int configfs_register_subsystem(struct configfs_subsystem *subsys) | |
1577 | { | |
1578 | int err; | |
1579 | struct config_group *group = &subsys->su_group; | |
1580 | struct qstr name; | |
1581 | struct dentry *dentry; | |
1582 | struct configfs_dirent *sd; | |
1583 | ||
1584 | err = configfs_pin_fs(); | |
1585 | if (err) | |
1586 | return err; | |
1587 | ||
1588 | if (!group->cg_item.ci_name) | |
1589 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
1590 | ||
1591 | sd = configfs_sb->s_root->d_fsdata; | |
1592 | link_group(to_config_group(sd->s_element), group); | |
1593 | ||
ba611edf JP |
1594 | mutex_lock_nested(&configfs_sb->s_root->d_inode->i_mutex, |
1595 | I_MUTEX_PARENT); | |
7063fbf2 JB |
1596 | |
1597 | name.name = group->cg_item.ci_name; | |
1598 | name.len = strlen(name.name); | |
1599 | name.hash = full_name_hash(name.name, name.len); | |
1600 | ||
1601 | err = -ENOMEM; | |
1602 | dentry = d_alloc(configfs_sb->s_root, &name); | |
afdf04ea JB |
1603 | if (dentry) { |
1604 | d_add(dentry, NULL); | |
7063fbf2 | 1605 | |
afdf04ea JB |
1606 | err = configfs_attach_group(sd->s_element, &group->cg_item, |
1607 | dentry); | |
1608 | if (err) { | |
1609 | d_delete(dentry); | |
1610 | dput(dentry); | |
2a109f2a LR |
1611 | } else { |
1612 | spin_lock(&configfs_dirent_lock); | |
1613 | configfs_dir_set_ready(dentry->d_fsdata); | |
1614 | spin_unlock(&configfs_dirent_lock); | |
afdf04ea JB |
1615 | } |
1616 | } | |
7063fbf2 | 1617 | |
1b1dcc1b | 1618 | mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex); |
7063fbf2 | 1619 | |
afdf04ea JB |
1620 | if (err) { |
1621 | unlink_group(group); | |
1622 | configfs_release_fs(); | |
7063fbf2 JB |
1623 | } |
1624 | ||
1625 | return err; | |
1626 | } | |
1627 | ||
1628 | void configfs_unregister_subsystem(struct configfs_subsystem *subsys) | |
1629 | { | |
1630 | struct config_group *group = &subsys->su_group; | |
1631 | struct dentry *dentry = group->cg_item.ci_dentry; | |
1632 | ||
1633 | if (dentry->d_parent != configfs_sb->s_root) { | |
1634 | printk(KERN_ERR "configfs: Tried to unregister non-subsystem!\n"); | |
1635 | return; | |
1636 | } | |
1637 | ||
55ed1602 MF |
1638 | mutex_lock_nested(&configfs_sb->s_root->d_inode->i_mutex, |
1639 | I_MUTEX_PARENT); | |
1640 | mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); | |
9a73d78c | 1641 | mutex_lock(&configfs_symlink_mutex); |
b3e76af8 | 1642 | spin_lock(&configfs_dirent_lock); |
6d8344ba | 1643 | if (configfs_detach_prep(dentry, NULL)) { |
7063fbf2 JB |
1644 | printk(KERN_ERR "configfs: Tried to unregister non-empty subsystem!\n"); |
1645 | } | |
b3e76af8 | 1646 | spin_unlock(&configfs_dirent_lock); |
9a73d78c | 1647 | mutex_unlock(&configfs_symlink_mutex); |
7063fbf2 JB |
1648 | configfs_detach_group(&group->cg_item); |
1649 | dentry->d_inode->i_flags |= S_DEAD; | |
1b1dcc1b | 1650 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1651 | |
1652 | d_delete(dentry); | |
1653 | ||
1b1dcc1b | 1654 | mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex); |
7063fbf2 JB |
1655 | |
1656 | dput(dentry); | |
1657 | ||
1658 | unlink_group(group); | |
1659 | configfs_release_fs(); | |
1660 | } | |
1661 | ||
1662 | EXPORT_SYMBOL(configfs_register_subsystem); | |
1663 | EXPORT_SYMBOL(configfs_unregister_subsystem); |