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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 | { | |
24307aa1 | 56 | struct configfs_dirent *sd = dentry->d_fsdata; |
7063fbf2 JB |
57 | |
58 | if (sd) { | |
24307aa1 JB |
59 | /* Coordinate with configfs_readdir */ |
60 | spin_lock(&configfs_dirent_lock); | |
76ae281f JB |
61 | /* Coordinate with configfs_attach_attr where will increase |
62 | * sd->s_count and update sd->s_dentry to new allocated one. | |
63 | * Only set sd->dentry to null when this dentry is the only | |
64 | * sd owner. | |
65 | * If not do so, configfs_d_iput may run just after | |
66 | * configfs_attach_attr and set sd->s_dentry to null | |
67 | * even it's still in use. | |
68 | */ | |
69 | if (atomic_read(&sd->s_count) <= 2) | |
70 | sd->s_dentry = NULL; | |
71 | ||
24307aa1 | 72 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
73 | configfs_put(sd); |
74 | } | |
75 | iput(inode); | |
76 | } | |
77 | ||
d463a0c4 | 78 | const struct dentry_operations configfs_dentry_ops = { |
7063fbf2 | 79 | .d_iput = configfs_d_iput, |
b26d4cd3 | 80 | .d_delete = always_delete_dentry, |
7063fbf2 JB |
81 | }; |
82 | ||
e74cc06d LR |
83 | #ifdef CONFIG_LOCKDEP |
84 | ||
85 | /* | |
86 | * Helpers to make lockdep happy with our recursive locking of default groups' | |
87 | * inodes (see configfs_attach_group() and configfs_detach_group()). | |
88 | * We put default groups i_mutexes in separate classes according to their depth | |
89 | * from the youngest non-default group ancestor. | |
90 | * | |
91 | * For a non-default group A having default groups A/B, A/C, and A/C/D, default | |
92 | * groups A/B and A/C will have their inode's mutex in class | |
93 | * default_group_class[0], and default group A/C/D will be in | |
94 | * default_group_class[1]. | |
95 | * | |
96 | * The lock classes are declared and assigned in inode.c, according to the | |
97 | * s_depth value. | |
98 | * The s_depth value is initialized to -1, adjusted to >= 0 when attaching | |
99 | * default groups, and reset to -1 when all default groups are attached. During | |
100 | * attachment, if configfs_create() sees s_depth > 0, the lock class of the new | |
101 | * inode's mutex is set to default_group_class[s_depth - 1]. | |
102 | */ | |
103 | ||
104 | static void configfs_init_dirent_depth(struct configfs_dirent *sd) | |
105 | { | |
106 | sd->s_depth = -1; | |
107 | } | |
108 | ||
109 | static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd, | |
110 | struct configfs_dirent *sd) | |
111 | { | |
112 | int parent_depth = parent_sd->s_depth; | |
113 | ||
114 | if (parent_depth >= 0) | |
115 | sd->s_depth = parent_depth + 1; | |
116 | } | |
117 | ||
118 | static void | |
119 | configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd) | |
120 | { | |
121 | /* | |
122 | * item's i_mutex class is already setup, so s_depth is now only | |
123 | * used to set new sub-directories s_depth, which is always done | |
124 | * with item's i_mutex locked. | |
125 | */ | |
126 | /* | |
127 | * sd->s_depth == -1 iff we are a non default group. | |
128 | * else (we are a default group) sd->s_depth > 0 (see | |
129 | * create_dir()). | |
130 | */ | |
131 | if (sd->s_depth == -1) | |
132 | /* | |
133 | * We are a non default group and we are going to create | |
134 | * default groups. | |
135 | */ | |
136 | sd->s_depth = 0; | |
137 | } | |
138 | ||
139 | static void | |
140 | configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd) | |
141 | { | |
142 | /* We will not create default groups anymore. */ | |
143 | sd->s_depth = -1; | |
144 | } | |
145 | ||
146 | #else /* CONFIG_LOCKDEP */ | |
147 | ||
148 | static void configfs_init_dirent_depth(struct configfs_dirent *sd) | |
149 | { | |
150 | } | |
151 | ||
152 | static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd, | |
153 | struct configfs_dirent *sd) | |
154 | { | |
155 | } | |
156 | ||
157 | static void | |
158 | configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd) | |
159 | { | |
160 | } | |
161 | ||
162 | static void | |
163 | configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd) | |
164 | { | |
165 | } | |
166 | ||
167 | #endif /* CONFIG_LOCKDEP */ | |
168 | ||
7063fbf2 JB |
169 | /* |
170 | * Allocates a new configfs_dirent and links it to the parent configfs_dirent | |
171 | */ | |
420118ca LR |
172 | static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *parent_sd, |
173 | void *element, int type) | |
7063fbf2 JB |
174 | { |
175 | struct configfs_dirent * sd; | |
176 | ||
c3762229 | 177 | sd = kmem_cache_zalloc(configfs_dir_cachep, GFP_KERNEL); |
7063fbf2 | 178 | if (!sd) |
107ed40b | 179 | return ERR_PTR(-ENOMEM); |
7063fbf2 | 180 | |
7063fbf2 JB |
181 | atomic_set(&sd->s_count, 1); |
182 | INIT_LIST_HEAD(&sd->s_links); | |
183 | INIT_LIST_HEAD(&sd->s_children); | |
7063fbf2 | 184 | sd->s_element = element; |
420118ca | 185 | sd->s_type = type; |
e74cc06d | 186 | configfs_init_dirent_depth(sd); |
6f610764 | 187 | spin_lock(&configfs_dirent_lock); |
b3e76af8 LR |
188 | if (parent_sd->s_type & CONFIGFS_USET_DROPPING) { |
189 | spin_unlock(&configfs_dirent_lock); | |
190 | kmem_cache_free(configfs_dir_cachep, sd); | |
191 | return ERR_PTR(-ENOENT); | |
192 | } | |
6f610764 LR |
193 | list_add(&sd->s_sibling, &parent_sd->s_children); |
194 | spin_unlock(&configfs_dirent_lock); | |
7063fbf2 JB |
195 | |
196 | return sd; | |
197 | } | |
198 | ||
b4c98f62 JB |
199 | /* |
200 | * | |
201 | * Return -EEXIST if there is already a configfs element with the same | |
202 | * name for the same parent. | |
203 | * | |
204 | * called with parent inode's i_mutex held | |
205 | */ | |
58d206c2 AB |
206 | static int configfs_dirent_exists(struct configfs_dirent *parent_sd, |
207 | const unsigned char *new) | |
b4c98f62 JB |
208 | { |
209 | struct configfs_dirent * sd; | |
210 | ||
211 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
212 | if (sd->s_element) { | |
213 | const unsigned char *existing = configfs_get_name(sd); | |
214 | if (strcmp(existing, new)) | |
215 | continue; | |
216 | else | |
217 | return -EEXIST; | |
218 | } | |
219 | } | |
220 | ||
221 | return 0; | |
222 | } | |
223 | ||
224 | ||
7063fbf2 JB |
225 | int configfs_make_dirent(struct configfs_dirent * parent_sd, |
226 | struct dentry * dentry, void * element, | |
227 | umode_t mode, int type) | |
228 | { | |
229 | struct configfs_dirent * sd; | |
230 | ||
420118ca | 231 | sd = configfs_new_dirent(parent_sd, element, type); |
107ed40b LR |
232 | if (IS_ERR(sd)) |
233 | return PTR_ERR(sd); | |
7063fbf2 JB |
234 | |
235 | sd->s_mode = mode; | |
7063fbf2 | 236 | sd->s_dentry = dentry; |
fbc8d4c0 | 237 | if (dentry) |
7063fbf2 | 238 | dentry->d_fsdata = configfs_get(sd); |
7063fbf2 JB |
239 | |
240 | return 0; | |
241 | } | |
242 | ||
c88b1e70 | 243 | static void init_dir(struct inode * inode) |
7063fbf2 JB |
244 | { |
245 | inode->i_op = &configfs_dir_inode_operations; | |
246 | inode->i_fop = &configfs_dir_operations; | |
247 | ||
248 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |
d8c76e6f | 249 | inc_nlink(inode); |
7063fbf2 JB |
250 | } |
251 | ||
c88b1e70 | 252 | static void configfs_init_file(struct inode * inode) |
7063fbf2 JB |
253 | { |
254 | inode->i_size = PAGE_SIZE; | |
255 | inode->i_fop = &configfs_file_operations; | |
7063fbf2 JB |
256 | } |
257 | ||
c88b1e70 | 258 | static void init_symlink(struct inode * inode) |
7063fbf2 JB |
259 | { |
260 | inode->i_op = &configfs_symlink_inode_operations; | |
7063fbf2 JB |
261 | } |
262 | ||
7063fbf2 JB |
263 | /** |
264 | * configfs_create_dir - create a directory for an config_item. | |
265 | * @item: config_itemwe're creating directory for. | |
266 | * @dentry: config_item's dentry. | |
2a109f2a LR |
267 | * |
268 | * Note: user-created entries won't be allowed under this new directory | |
269 | * until it is validated by configfs_dir_set_ready() | |
7063fbf2 JB |
270 | */ |
271 | ||
1cf97d0d | 272 | static int configfs_create_dir(struct config_item *item, struct dentry *dentry) |
7063fbf2 | 273 | { |
1cf97d0d AV |
274 | int error; |
275 | umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; | |
276 | struct dentry *p = dentry->d_parent; | |
277 | ||
278 | BUG_ON(!item); | |
279 | ||
280 | error = configfs_dirent_exists(p->d_fsdata, dentry->d_name.name); | |
281 | if (unlikely(error)) | |
282 | return error; | |
283 | ||
284 | error = configfs_make_dirent(p->d_fsdata, dentry, item, mode, | |
285 | CONFIGFS_DIR | CONFIGFS_USET_CREATING); | |
286 | if (unlikely(error)) | |
287 | return error; | |
288 | ||
289 | configfs_set_dir_dirent_depth(p->d_fsdata, dentry->d_fsdata); | |
290 | error = configfs_create(dentry, mode, init_dir); | |
291 | if (!error) { | |
2b0143b5 | 292 | inc_nlink(d_inode(p)); |
7063fbf2 | 293 | item->ci_dentry = dentry; |
1cf97d0d AV |
294 | } else { |
295 | struct configfs_dirent *sd = dentry->d_fsdata; | |
296 | if (sd) { | |
297 | spin_lock(&configfs_dirent_lock); | |
298 | list_del_init(&sd->s_sibling); | |
299 | spin_unlock(&configfs_dirent_lock); | |
300 | configfs_put(sd); | |
301 | } | |
302 | } | |
7063fbf2 JB |
303 | return error; |
304 | } | |
305 | ||
2a109f2a LR |
306 | /* |
307 | * Allow userspace to create new entries under a new directory created with | |
308 | * configfs_create_dir(), and under all of its chidlren directories recursively. | |
309 | * @sd configfs_dirent of the new directory to validate | |
310 | * | |
311 | * Caller must hold configfs_dirent_lock. | |
312 | */ | |
313 | static void configfs_dir_set_ready(struct configfs_dirent *sd) | |
314 | { | |
315 | struct configfs_dirent *child_sd; | |
316 | ||
317 | sd->s_type &= ~CONFIGFS_USET_CREATING; | |
318 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) | |
319 | if (child_sd->s_type & CONFIGFS_USET_CREATING) | |
320 | configfs_dir_set_ready(child_sd); | |
321 | } | |
322 | ||
323 | /* | |
324 | * Check that a directory does not belong to a directory hierarchy being | |
325 | * attached and not validated yet. | |
326 | * @sd configfs_dirent of the directory to check | |
327 | * | |
328 | * @return non-zero iff the directory was validated | |
329 | * | |
330 | * Note: takes configfs_dirent_lock, so the result may change from false to true | |
331 | * in two consecutive calls, but never from true to false. | |
332 | */ | |
333 | int configfs_dirent_is_ready(struct configfs_dirent *sd) | |
334 | { | |
335 | int ret; | |
336 | ||
337 | spin_lock(&configfs_dirent_lock); | |
338 | ret = !(sd->s_type & CONFIGFS_USET_CREATING); | |
339 | spin_unlock(&configfs_dirent_lock); | |
340 | ||
341 | return ret; | |
342 | } | |
343 | ||
7063fbf2 JB |
344 | int configfs_create_link(struct configfs_symlink *sl, |
345 | struct dentry *parent, | |
346 | struct dentry *dentry) | |
347 | { | |
348 | int err = 0; | |
349 | umode_t mode = S_IFLNK | S_IRWXUGO; | |
350 | ||
3d0f89bb JB |
351 | err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode, |
352 | CONFIGFS_ITEM_LINK); | |
7063fbf2 | 353 | if (!err) { |
3d0f89bb | 354 | err = configfs_create(dentry, mode, init_symlink); |
fbc8d4c0 | 355 | if (err) { |
3d0f89bb JB |
356 | struct configfs_dirent *sd = dentry->d_fsdata; |
357 | if (sd) { | |
6f610764 | 358 | spin_lock(&configfs_dirent_lock); |
3d0f89bb | 359 | list_del_init(&sd->s_sibling); |
6f610764 | 360 | spin_unlock(&configfs_dirent_lock); |
3d0f89bb JB |
361 | configfs_put(sd); |
362 | } | |
363 | } | |
7063fbf2 JB |
364 | } |
365 | return err; | |
366 | } | |
367 | ||
368 | static void remove_dir(struct dentry * d) | |
369 | { | |
370 | struct dentry * parent = dget(d->d_parent); | |
371 | struct configfs_dirent * sd; | |
372 | ||
373 | sd = d->d_fsdata; | |
6f610764 | 374 | spin_lock(&configfs_dirent_lock); |
e7515d06 | 375 | list_del_init(&sd->s_sibling); |
6f610764 | 376 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 | 377 | configfs_put(sd); |
2b0143b5 DH |
378 | if (d_really_is_positive(d)) |
379 | simple_rmdir(d_inode(parent),d); | |
7063fbf2 | 380 | |
a455589f | 381 | pr_debug(" o %pd removing done (%d)\n", d, d_count(d)); |
7063fbf2 JB |
382 | |
383 | dput(parent); | |
384 | } | |
385 | ||
386 | /** | |
387 | * configfs_remove_dir - remove an config_item's directory. | |
388 | * @item: config_item we're removing. | |
389 | * | |
390 | * The only thing special about this is that we remove any files in | |
391 | * the directory before we remove the directory, and we've inlined | |
392 | * what used to be configfs_rmdir() below, instead of calling separately. | |
2e2ce171 LR |
393 | * |
394 | * Caller holds the mutex of the item's inode | |
7063fbf2 JB |
395 | */ |
396 | ||
397 | static void configfs_remove_dir(struct config_item * item) | |
398 | { | |
399 | struct dentry * dentry = dget(item->ci_dentry); | |
400 | ||
401 | if (!dentry) | |
402 | return; | |
403 | ||
404 | remove_dir(dentry); | |
405 | /** | |
406 | * Drop reference from dget() on entrance. | |
407 | */ | |
408 | dput(dentry); | |
409 | } | |
410 | ||
411 | ||
412 | /* attaches attribute's configfs_dirent to the dentry corresponding to the | |
413 | * attribute file | |
414 | */ | |
415 | static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry) | |
416 | { | |
417 | struct configfs_attribute * attr = sd->s_element; | |
418 | int error; | |
419 | ||
76ae281f | 420 | spin_lock(&configfs_dirent_lock); |
3d0f89bb JB |
421 | dentry->d_fsdata = configfs_get(sd); |
422 | sd->s_dentry = dentry; | |
76ae281f JB |
423 | spin_unlock(&configfs_dirent_lock); |
424 | ||
ce8d2cdf DH |
425 | error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG, |
426 | configfs_init_file); | |
3d0f89bb JB |
427 | if (error) { |
428 | configfs_put(sd); | |
7063fbf2 | 429 | return error; |
3d0f89bb | 430 | } |
7063fbf2 | 431 | |
7063fbf2 JB |
432 | d_rehash(dentry); |
433 | ||
434 | return 0; | |
435 | } | |
436 | ||
437 | static struct dentry * configfs_lookup(struct inode *dir, | |
438 | struct dentry *dentry, | |
00cd8dd3 | 439 | unsigned int flags) |
7063fbf2 JB |
440 | { |
441 | struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata; | |
442 | struct configfs_dirent * sd; | |
443 | int found = 0; | |
2a109f2a LR |
444 | int err; |
445 | ||
446 | /* | |
447 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
448 | * being attached | |
449 | * | |
450 | * This forbids userspace to read/write attributes of items which may | |
451 | * not complete their initialization, since the dentries of the | |
452 | * attributes won't be instantiated. | |
453 | */ | |
454 | err = -ENOENT; | |
455 | if (!configfs_dirent_is_ready(parent_sd)) | |
456 | goto out; | |
7063fbf2 JB |
457 | |
458 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
459 | if (sd->s_type & CONFIGFS_NOT_PINNED) { | |
460 | const unsigned char * name = configfs_get_name(sd); | |
461 | ||
462 | if (strcmp(name, dentry->d_name.name)) | |
463 | continue; | |
464 | ||
465 | found = 1; | |
466 | err = configfs_attach_attr(sd, dentry); | |
467 | break; | |
468 | } | |
469 | } | |
470 | ||
471 | if (!found) { | |
472 | /* | |
473 | * If it doesn't exist and it isn't a NOT_PINNED item, | |
474 | * it must be negative. | |
475 | */ | |
fbc8d4c0 NP |
476 | if (dentry->d_name.len > NAME_MAX) |
477 | return ERR_PTR(-ENAMETOOLONG); | |
fbc8d4c0 NP |
478 | d_add(dentry, NULL); |
479 | return NULL; | |
7063fbf2 JB |
480 | } |
481 | ||
2a109f2a | 482 | out: |
7063fbf2 JB |
483 | return ERR_PTR(err); |
484 | } | |
485 | ||
486 | /* | |
487 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are | |
b3e76af8 LR |
488 | * attributes and are removed by rmdir(). We recurse, setting |
489 | * CONFIGFS_USET_DROPPING on all children that are candidates for | |
490 | * default detach. | |
491 | * If there is an error, the caller will reset the flags via | |
492 | * configfs_detach_rollback(). | |
7063fbf2 | 493 | */ |
6d8344ba | 494 | static int configfs_detach_prep(struct dentry *dentry, struct mutex **wait_mutex) |
7063fbf2 JB |
495 | { |
496 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
497 | struct configfs_dirent *sd; | |
498 | int ret; | |
499 | ||
4768e9b1 LR |
500 | /* Mark that we're trying to drop the group */ |
501 | parent_sd->s_type |= CONFIGFS_USET_DROPPING; | |
502 | ||
7063fbf2 JB |
503 | ret = -EBUSY; |
504 | if (!list_empty(&parent_sd->s_links)) | |
505 | goto out; | |
506 | ||
507 | ret = 0; | |
508 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
99cefda4 LR |
509 | if (!sd->s_element || |
510 | (sd->s_type & CONFIGFS_NOT_PINNED)) | |
7063fbf2 JB |
511 | continue; |
512 | if (sd->s_type & CONFIGFS_USET_DEFAULT) { | |
6d8344ba LR |
513 | /* Abort if racing with mkdir() */ |
514 | if (sd->s_type & CONFIGFS_USET_IN_MKDIR) { | |
515 | if (wait_mutex) | |
2b0143b5 | 516 | *wait_mutex = &d_inode(sd->s_dentry)->i_mutex; |
6d8344ba LR |
517 | return -EAGAIN; |
518 | } | |
7063fbf2 | 519 | |
631d1feb JB |
520 | /* |
521 | * Yup, recursive. If there's a problem, blame | |
522 | * deep nesting of default_groups | |
523 | */ | |
6d8344ba | 524 | ret = configfs_detach_prep(sd->s_dentry, wait_mutex); |
7063fbf2 | 525 | if (!ret) |
e7515d06 | 526 | continue; |
7063fbf2 JB |
527 | } else |
528 | ret = -ENOTEMPTY; | |
529 | ||
530 | break; | |
531 | } | |
532 | ||
533 | out: | |
534 | return ret; | |
535 | } | |
536 | ||
537 | /* | |
b3e76af8 | 538 | * Walk the tree, resetting CONFIGFS_USET_DROPPING wherever it was |
7063fbf2 JB |
539 | * set. |
540 | */ | |
541 | static void configfs_detach_rollback(struct dentry *dentry) | |
542 | { | |
543 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
544 | struct configfs_dirent *sd; | |
545 | ||
4768e9b1 LR |
546 | parent_sd->s_type &= ~CONFIGFS_USET_DROPPING; |
547 | ||
548 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) | |
549 | if (sd->s_type & CONFIGFS_USET_DEFAULT) | |
7063fbf2 | 550 | configfs_detach_rollback(sd->s_dentry); |
7063fbf2 JB |
551 | } |
552 | ||
553 | static void detach_attrs(struct config_item * item) | |
554 | { | |
555 | struct dentry * dentry = dget(item->ci_dentry); | |
556 | struct configfs_dirent * parent_sd; | |
557 | struct configfs_dirent * sd, * tmp; | |
558 | ||
559 | if (!dentry) | |
560 | return; | |
561 | ||
562 | pr_debug("configfs %s: dropping attrs for dir\n", | |
563 | dentry->d_name.name); | |
564 | ||
565 | parent_sd = dentry->d_fsdata; | |
566 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
567 | if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED)) | |
568 | continue; | |
6f610764 | 569 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 570 | list_del_init(&sd->s_sibling); |
6f610764 | 571 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
572 | configfs_drop_dentry(sd, dentry); |
573 | configfs_put(sd); | |
574 | } | |
575 | ||
576 | /** | |
577 | * Drop reference from dget() on entrance. | |
578 | */ | |
579 | dput(dentry); | |
580 | } | |
581 | ||
582 | static int populate_attrs(struct config_item *item) | |
583 | { | |
584 | struct config_item_type *t = item->ci_type; | |
585 | struct configfs_attribute *attr; | |
586 | int error = 0; | |
587 | int i; | |
588 | ||
589 | if (!t) | |
590 | return -EINVAL; | |
591 | if (t->ct_attrs) { | |
592 | for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) { | |
593 | if ((error = configfs_create_file(item, attr))) | |
594 | break; | |
595 | } | |
596 | } | |
597 | ||
598 | if (error) | |
599 | detach_attrs(item); | |
600 | ||
601 | return error; | |
602 | } | |
603 | ||
604 | static int configfs_attach_group(struct config_item *parent_item, | |
605 | struct config_item *item, | |
606 | struct dentry *dentry); | |
607 | static void configfs_detach_group(struct config_item *item); | |
608 | ||
609 | static void detach_groups(struct config_group *group) | |
610 | { | |
611 | struct dentry * dentry = dget(group->cg_item.ci_dentry); | |
612 | struct dentry *child; | |
613 | struct configfs_dirent *parent_sd; | |
614 | struct configfs_dirent *sd, *tmp; | |
615 | ||
616 | if (!dentry) | |
617 | return; | |
618 | ||
619 | parent_sd = dentry->d_fsdata; | |
620 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
621 | if (!sd->s_element || | |
622 | !(sd->s_type & CONFIGFS_USET_DEFAULT)) | |
623 | continue; | |
624 | ||
625 | child = sd->s_dentry; | |
626 | ||
2b0143b5 | 627 | mutex_lock(&d_inode(child)->i_mutex); |
b3e76af8 | 628 | |
7063fbf2 | 629 | configfs_detach_group(sd->s_element); |
2b0143b5 | 630 | d_inode(child)->i_flags |= S_DEAD; |
d83c49f3 | 631 | dont_mount(child); |
7063fbf2 | 632 | |
2b0143b5 | 633 | mutex_unlock(&d_inode(child)->i_mutex); |
7063fbf2 JB |
634 | |
635 | d_delete(child); | |
636 | dput(child); | |
637 | } | |
638 | ||
639 | /** | |
640 | * Drop reference from dget() on entrance. | |
641 | */ | |
642 | dput(dentry); | |
643 | } | |
644 | ||
645 | /* | |
646 | * This fakes mkdir(2) on a default_groups[] entry. It | |
647 | * creates a dentry, attachs it, and then does fixup | |
648 | * on the sd->s_type. | |
649 | * | |
650 | * We could, perhaps, tweak our parent's ->mkdir for a minute and | |
651 | * try using vfs_mkdir. Just a thought. | |
652 | */ | |
653 | static int create_default_group(struct config_group *parent_group, | |
654 | struct config_group *group) | |
655 | { | |
656 | int ret; | |
7063fbf2 JB |
657 | struct configfs_dirent *sd; |
658 | /* We trust the caller holds a reference to parent */ | |
659 | struct dentry *child, *parent = parent_group->cg_item.ci_dentry; | |
660 | ||
661 | if (!group->cg_item.ci_name) | |
662 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
7063fbf2 JB |
663 | |
664 | ret = -ENOMEM; | |
ec193cf5 | 665 | child = d_alloc_name(parent, group->cg_item.ci_name); |
7063fbf2 JB |
666 | if (child) { |
667 | d_add(child, NULL); | |
668 | ||
669 | ret = configfs_attach_group(&parent_group->cg_item, | |
670 | &group->cg_item, child); | |
671 | if (!ret) { | |
672 | sd = child->d_fsdata; | |
673 | sd->s_type |= CONFIGFS_USET_DEFAULT; | |
674 | } else { | |
2b0143b5 | 675 | BUG_ON(d_inode(child)); |
df7f9967 | 676 | d_drop(child); |
7063fbf2 JB |
677 | dput(child); |
678 | } | |
679 | } | |
680 | ||
681 | return ret; | |
682 | } | |
683 | ||
684 | static int populate_groups(struct config_group *group) | |
685 | { | |
686 | struct config_group *new_group; | |
7063fbf2 JB |
687 | int ret = 0; |
688 | int i; | |
689 | ||
cbca692c | 690 | if (group->default_groups) { |
7063fbf2 JB |
691 | for (i = 0; group->default_groups[i]; i++) { |
692 | new_group = group->default_groups[i]; | |
693 | ||
694 | ret = create_default_group(group, new_group); | |
2e2ce171 LR |
695 | if (ret) { |
696 | detach_groups(group); | |
7063fbf2 | 697 | break; |
2e2ce171 | 698 | } |
7063fbf2 | 699 | } |
7063fbf2 JB |
700 | } |
701 | ||
7063fbf2 JB |
702 | return ret; |
703 | } | |
704 | ||
705 | /* | |
706 | * All of link_obj/unlink_obj/link_group/unlink_group require that | |
e6bd07ae | 707 | * subsys->su_mutex is held. |
7063fbf2 JB |
708 | */ |
709 | ||
710 | static void unlink_obj(struct config_item *item) | |
711 | { | |
712 | struct config_group *group; | |
713 | ||
714 | group = item->ci_group; | |
715 | if (group) { | |
716 | list_del_init(&item->ci_entry); | |
717 | ||
718 | item->ci_group = NULL; | |
719 | item->ci_parent = NULL; | |
eed7a0db JB |
720 | |
721 | /* Drop the reference for ci_entry */ | |
7063fbf2 JB |
722 | config_item_put(item); |
723 | ||
eed7a0db | 724 | /* Drop the reference for ci_parent */ |
7063fbf2 JB |
725 | config_group_put(group); |
726 | } | |
727 | } | |
728 | ||
729 | static void link_obj(struct config_item *parent_item, struct config_item *item) | |
730 | { | |
eed7a0db JB |
731 | /* |
732 | * Parent seems redundant with group, but it makes certain | |
733 | * traversals much nicer. | |
734 | */ | |
7063fbf2 | 735 | item->ci_parent = parent_item; |
eed7a0db JB |
736 | |
737 | /* | |
738 | * We hold a reference on the parent for the child's ci_parent | |
739 | * link. | |
740 | */ | |
7063fbf2 JB |
741 | item->ci_group = config_group_get(to_config_group(parent_item)); |
742 | list_add_tail(&item->ci_entry, &item->ci_group->cg_children); | |
743 | ||
eed7a0db JB |
744 | /* |
745 | * We hold a reference on the child for ci_entry on the parent's | |
746 | * cg_children | |
747 | */ | |
7063fbf2 JB |
748 | config_item_get(item); |
749 | } | |
750 | ||
751 | static void unlink_group(struct config_group *group) | |
752 | { | |
753 | int i; | |
754 | struct config_group *new_group; | |
755 | ||
756 | if (group->default_groups) { | |
757 | for (i = 0; group->default_groups[i]; i++) { | |
758 | new_group = group->default_groups[i]; | |
759 | unlink_group(new_group); | |
760 | } | |
761 | } | |
762 | ||
763 | group->cg_subsys = NULL; | |
764 | unlink_obj(&group->cg_item); | |
765 | } | |
766 | ||
767 | static void link_group(struct config_group *parent_group, struct config_group *group) | |
768 | { | |
769 | int i; | |
770 | struct config_group *new_group; | |
771 | struct configfs_subsystem *subsys = NULL; /* gcc is a turd */ | |
772 | ||
773 | link_obj(&parent_group->cg_item, &group->cg_item); | |
774 | ||
775 | if (parent_group->cg_subsys) | |
776 | subsys = parent_group->cg_subsys; | |
777 | else if (configfs_is_root(&parent_group->cg_item)) | |
778 | subsys = to_configfs_subsystem(group); | |
779 | else | |
780 | BUG(); | |
781 | group->cg_subsys = subsys; | |
782 | ||
783 | if (group->default_groups) { | |
784 | for (i = 0; group->default_groups[i]; i++) { | |
785 | new_group = group->default_groups[i]; | |
786 | link_group(group, new_group); | |
787 | } | |
788 | } | |
789 | } | |
790 | ||
791 | /* | |
792 | * The goal is that configfs_attach_item() (and | |
793 | * configfs_attach_group()) can be called from either the VFS or this | |
794 | * module. That is, they assume that the items have been created, | |
795 | * the dentry allocated, and the dcache is all ready to go. | |
796 | * | |
797 | * If they fail, they must clean up after themselves as if they | |
798 | * had never been called. The caller (VFS or local function) will | |
799 | * handle cleaning up the dcache bits. | |
800 | * | |
801 | * configfs_detach_group() and configfs_detach_item() behave similarly on | |
802 | * the way out. They assume that the proper semaphores are held, they | |
803 | * clean up the configfs items, and they expect their callers will | |
804 | * handle the dcache bits. | |
805 | */ | |
806 | static int configfs_attach_item(struct config_item *parent_item, | |
807 | struct config_item *item, | |
808 | struct dentry *dentry) | |
809 | { | |
810 | int ret; | |
811 | ||
812 | ret = configfs_create_dir(item, dentry); | |
813 | if (!ret) { | |
814 | ret = populate_attrs(item); | |
815 | if (ret) { | |
2e2ce171 LR |
816 | /* |
817 | * We are going to remove an inode and its dentry but | |
818 | * the VFS may already have hit and used them. Thus, | |
819 | * we must lock them as rmdir() would. | |
820 | */ | |
2b0143b5 | 821 | mutex_lock(&d_inode(dentry)->i_mutex); |
7063fbf2 | 822 | configfs_remove_dir(item); |
2b0143b5 | 823 | d_inode(dentry)->i_flags |= S_DEAD; |
d83c49f3 | 824 | dont_mount(dentry); |
2b0143b5 | 825 | mutex_unlock(&d_inode(dentry)->i_mutex); |
7063fbf2 JB |
826 | d_delete(dentry); |
827 | } | |
828 | } | |
829 | ||
830 | return ret; | |
831 | } | |
832 | ||
2e2ce171 | 833 | /* Caller holds the mutex of the item's inode */ |
7063fbf2 JB |
834 | static void configfs_detach_item(struct config_item *item) |
835 | { | |
836 | detach_attrs(item); | |
837 | configfs_remove_dir(item); | |
838 | } | |
839 | ||
840 | static int configfs_attach_group(struct config_item *parent_item, | |
841 | struct config_item *item, | |
842 | struct dentry *dentry) | |
843 | { | |
844 | int ret; | |
845 | struct configfs_dirent *sd; | |
846 | ||
847 | ret = configfs_attach_item(parent_item, item, dentry); | |
848 | if (!ret) { | |
849 | sd = dentry->d_fsdata; | |
850 | sd->s_type |= CONFIGFS_USET_DIR; | |
851 | ||
2e2ce171 LR |
852 | /* |
853 | * FYI, we're faking mkdir in populate_groups() | |
854 | * We must lock the group's inode to avoid races with the VFS | |
855 | * which can already hit the inode and try to add/remove entries | |
856 | * under it. | |
857 | * | |
858 | * We must also lock the inode to remove it safely in case of | |
859 | * error, as rmdir() would. | |
860 | */ | |
2b0143b5 | 861 | mutex_lock_nested(&d_inode(dentry)->i_mutex, I_MUTEX_CHILD); |
e74cc06d | 862 | configfs_adjust_dir_dirent_depth_before_populate(sd); |
7063fbf2 JB |
863 | ret = populate_groups(to_config_group(item)); |
864 | if (ret) { | |
865 | configfs_detach_item(item); | |
2b0143b5 | 866 | d_inode(dentry)->i_flags |= S_DEAD; |
d83c49f3 | 867 | dont_mount(dentry); |
7063fbf2 | 868 | } |
e74cc06d | 869 | configfs_adjust_dir_dirent_depth_after_populate(sd); |
2b0143b5 | 870 | mutex_unlock(&d_inode(dentry)->i_mutex); |
2e2ce171 LR |
871 | if (ret) |
872 | d_delete(dentry); | |
7063fbf2 JB |
873 | } |
874 | ||
875 | return ret; | |
876 | } | |
877 | ||
2e2ce171 | 878 | /* Caller holds the mutex of the group's inode */ |
7063fbf2 JB |
879 | static void configfs_detach_group(struct config_item *item) |
880 | { | |
881 | detach_groups(to_config_group(item)); | |
882 | configfs_detach_item(item); | |
883 | } | |
884 | ||
299894cc JB |
885 | /* |
886 | * After the item has been detached from the filesystem view, we are | |
887 | * ready to tear it out of the hierarchy. Notify the client before | |
888 | * we do that so they can perform any cleanup that requires | |
889 | * navigating the hierarchy. A client does not need to provide this | |
890 | * callback. The subsystem semaphore MUST be held by the caller, and | |
891 | * references must be valid for both items. It also assumes the | |
892 | * caller has validated ci_type. | |
893 | */ | |
894 | static void client_disconnect_notify(struct config_item *parent_item, | |
895 | struct config_item *item) | |
896 | { | |
897 | struct config_item_type *type; | |
898 | ||
899 | type = parent_item->ci_type; | |
900 | BUG_ON(!type); | |
901 | ||
902 | if (type->ct_group_ops && type->ct_group_ops->disconnect_notify) | |
903 | type->ct_group_ops->disconnect_notify(to_config_group(parent_item), | |
904 | item); | |
905 | } | |
906 | ||
7063fbf2 JB |
907 | /* |
908 | * Drop the initial reference from make_item()/make_group() | |
909 | * This function assumes that reference is held on item | |
910 | * and that item holds a valid reference to the parent. Also, it | |
911 | * assumes the caller has validated ci_type. | |
912 | */ | |
913 | static void client_drop_item(struct config_item *parent_item, | |
914 | struct config_item *item) | |
915 | { | |
916 | struct config_item_type *type; | |
917 | ||
918 | type = parent_item->ci_type; | |
919 | BUG_ON(!type); | |
920 | ||
eed7a0db JB |
921 | /* |
922 | * If ->drop_item() exists, it is responsible for the | |
923 | * config_item_put(). | |
924 | */ | |
7063fbf2 JB |
925 | if (type->ct_group_ops && type->ct_group_ops->drop_item) |
926 | type->ct_group_ops->drop_item(to_config_group(parent_item), | |
299894cc | 927 | item); |
7063fbf2 JB |
928 | else |
929 | config_item_put(item); | |
930 | } | |
931 | ||
631d1feb JB |
932 | #ifdef DEBUG |
933 | static void configfs_dump_one(struct configfs_dirent *sd, int level) | |
934 | { | |
c6686931 | 935 | pr_info("%*s\"%s\":\n", level, " ", configfs_get_name(sd)); |
631d1feb | 936 | |
c6686931 | 937 | #define type_print(_type) if (sd->s_type & _type) pr_info("%*s %s\n", level, " ", #_type); |
631d1feb JB |
938 | type_print(CONFIGFS_ROOT); |
939 | type_print(CONFIGFS_DIR); | |
940 | type_print(CONFIGFS_ITEM_ATTR); | |
941 | type_print(CONFIGFS_ITEM_LINK); | |
942 | type_print(CONFIGFS_USET_DIR); | |
943 | type_print(CONFIGFS_USET_DEFAULT); | |
944 | type_print(CONFIGFS_USET_DROPPING); | |
945 | #undef type_print | |
946 | } | |
947 | ||
948 | static int configfs_dump(struct configfs_dirent *sd, int level) | |
949 | { | |
950 | struct configfs_dirent *child_sd; | |
951 | int ret = 0; | |
952 | ||
953 | configfs_dump_one(sd, level); | |
954 | ||
955 | if (!(sd->s_type & (CONFIGFS_DIR|CONFIGFS_ROOT))) | |
956 | return 0; | |
957 | ||
958 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) { | |
959 | ret = configfs_dump(child_sd, level + 2); | |
960 | if (ret) | |
961 | break; | |
962 | } | |
963 | ||
964 | return ret; | |
965 | } | |
966 | #endif | |
967 | ||
968 | ||
969 | /* | |
970 | * configfs_depend_item() and configfs_undepend_item() | |
971 | * | |
972 | * WARNING: Do not call these from a configfs callback! | |
973 | * | |
974 | * This describes these functions and their helpers. | |
975 | * | |
976 | * Allow another kernel system to depend on a config_item. If this | |
25985edc | 977 | * happens, the item cannot go away until the dependent can live without |
631d1feb JB |
978 | * it. The idea is to give client modules as simple an interface as |
979 | * possible. When a system asks them to depend on an item, they just | |
980 | * call configfs_depend_item(). If the item is live and the client | |
981 | * driver is in good shape, we'll happily do the work for them. | |
982 | * | |
983 | * Why is the locking complex? Because configfs uses the VFS to handle | |
984 | * all locking, but this function is called outside the normal | |
985 | * VFS->configfs path. So it must take VFS locks to prevent the | |
986 | * VFS->configfs stuff (configfs_mkdir(), configfs_rmdir(), etc). This is | |
987 | * why you can't call these functions underneath configfs callbacks. | |
988 | * | |
989 | * Note, btw, that this can be called at *any* time, even when a configfs | |
990 | * subsystem isn't registered, or when configfs is loading or unloading. | |
991 | * Just like configfs_register_subsystem(). So we take the same | |
420118ca LR |
992 | * precautions. We pin the filesystem. We lock configfs_dirent_lock. |
993 | * If we can find the target item in the | |
631d1feb | 994 | * configfs tree, it must be part of the subsystem tree as well, so we |
420118ca LR |
995 | * do not need the subsystem semaphore. Holding configfs_dirent_lock helps |
996 | * locking out mkdir() and rmdir(), who might be racing us. | |
631d1feb JB |
997 | */ |
998 | ||
999 | /* | |
1000 | * configfs_depend_prep() | |
1001 | * | |
1002 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are | |
1003 | * attributes. This is similar but not the same to configfs_detach_prep(). | |
1004 | * Note that configfs_detach_prep() expects the parent to be locked when it | |
1005 | * is called, but we lock the parent *inside* configfs_depend_prep(). We | |
1006 | * do that so we can unlock it if we find nothing. | |
1007 | * | |
1008 | * Here we do a depth-first search of the dentry hierarchy looking for | |
420118ca LR |
1009 | * our object. |
1010 | * We deliberately ignore items tagged as dropping since they are virtually | |
1011 | * dead, as well as items in the middle of attachment since they virtually | |
1012 | * do not exist yet. This completes the locking out of racing mkdir() and | |
1013 | * rmdir(). | |
1014 | * Note: subdirectories in the middle of attachment start with s_type = | |
1015 | * CONFIGFS_DIR|CONFIGFS_USET_CREATING set by create_dir(). When | |
1016 | * CONFIGFS_USET_CREATING is set, we ignore the item. The actual set of | |
1017 | * s_type is in configfs_new_dirent(), which has configfs_dirent_lock. | |
631d1feb | 1018 | * |
420118ca | 1019 | * If the target is not found, -ENOENT is bubbled up. |
631d1feb JB |
1020 | * |
1021 | * This adds a requirement that all config_items be unique! | |
1022 | * | |
420118ca | 1023 | * This is recursive. There isn't |
631d1feb JB |
1024 | * much on the stack, though, so folks that need this function - be careful |
1025 | * about your stack! Patches will be accepted to make it iterative. | |
1026 | */ | |
1027 | static int configfs_depend_prep(struct dentry *origin, | |
1028 | struct config_item *target) | |
1029 | { | |
49deb4bc | 1030 | struct configfs_dirent *child_sd, *sd; |
631d1feb JB |
1031 | int ret = 0; |
1032 | ||
49deb4bc WY |
1033 | BUG_ON(!origin || !origin->d_fsdata); |
1034 | sd = origin->d_fsdata; | |
631d1feb | 1035 | |
631d1feb JB |
1036 | if (sd->s_element == target) /* Boo-yah */ |
1037 | goto out; | |
1038 | ||
1039 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) { | |
420118ca LR |
1040 | if ((child_sd->s_type & CONFIGFS_DIR) && |
1041 | !(child_sd->s_type & CONFIGFS_USET_DROPPING) && | |
1042 | !(child_sd->s_type & CONFIGFS_USET_CREATING)) { | |
631d1feb JB |
1043 | ret = configfs_depend_prep(child_sd->s_dentry, |
1044 | target); | |
1045 | if (!ret) | |
1046 | goto out; /* Child path boo-yah */ | |
1047 | } | |
1048 | } | |
1049 | ||
1050 | /* We looped all our children and didn't find target */ | |
631d1feb JB |
1051 | ret = -ENOENT; |
1052 | ||
1053 | out: | |
1054 | return ret; | |
1055 | } | |
1056 | ||
631d1feb JB |
1057 | int configfs_depend_item(struct configfs_subsystem *subsys, |
1058 | struct config_item *target) | |
1059 | { | |
1060 | int ret; | |
1061 | struct configfs_dirent *p, *root_sd, *subsys_sd = NULL; | |
1062 | struct config_item *s_item = &subsys->su_group.cg_item; | |
b7c177fc | 1063 | struct dentry *root; |
631d1feb JB |
1064 | |
1065 | /* | |
1066 | * Pin the configfs filesystem. This means we can safely access | |
1067 | * the root of the configfs filesystem. | |
1068 | */ | |
2a152ad3 AV |
1069 | root = configfs_pin_fs(); |
1070 | if (IS_ERR(root)) | |
1071 | return PTR_ERR(root); | |
631d1feb JB |
1072 | |
1073 | /* | |
1074 | * Next, lock the root directory. We're going to check that the | |
1075 | * subsystem is really registered, and so we need to lock out | |
1076 | * configfs_[un]register_subsystem(). | |
1077 | */ | |
2b0143b5 | 1078 | mutex_lock(&d_inode(root)->i_mutex); |
631d1feb | 1079 | |
b7c177fc | 1080 | root_sd = root->d_fsdata; |
631d1feb JB |
1081 | |
1082 | list_for_each_entry(p, &root_sd->s_children, s_sibling) { | |
1083 | if (p->s_type & CONFIGFS_DIR) { | |
1084 | if (p->s_element == s_item) { | |
1085 | subsys_sd = p; | |
1086 | break; | |
1087 | } | |
1088 | } | |
1089 | } | |
1090 | ||
1091 | if (!subsys_sd) { | |
1092 | ret = -ENOENT; | |
1093 | goto out_unlock_fs; | |
1094 | } | |
1095 | ||
1096 | /* Ok, now we can trust subsys/s_item */ | |
1097 | ||
420118ca LR |
1098 | spin_lock(&configfs_dirent_lock); |
1099 | /* Scan the tree, return 0 if found */ | |
631d1feb JB |
1100 | ret = configfs_depend_prep(subsys_sd->s_dentry, target); |
1101 | if (ret) | |
420118ca | 1102 | goto out_unlock_dirent_lock; |
631d1feb | 1103 | |
420118ca LR |
1104 | /* |
1105 | * We are sure that the item is not about to be removed by rmdir(), and | |
1106 | * not in the middle of attachment by mkdir(). | |
1107 | */ | |
631d1feb JB |
1108 | p = target->ci_dentry->d_fsdata; |
1109 | p->s_dependent_count += 1; | |
1110 | ||
420118ca LR |
1111 | out_unlock_dirent_lock: |
1112 | spin_unlock(&configfs_dirent_lock); | |
631d1feb | 1113 | out_unlock_fs: |
2b0143b5 | 1114 | mutex_unlock(&d_inode(root)->i_mutex); |
631d1feb JB |
1115 | |
1116 | /* | |
1117 | * If we succeeded, the fs is pinned via other methods. If not, | |
1118 | * we're done with it anyway. So release_fs() is always right. | |
1119 | */ | |
1120 | configfs_release_fs(); | |
1121 | ||
1122 | return ret; | |
1123 | } | |
1124 | EXPORT_SYMBOL(configfs_depend_item); | |
1125 | ||
1126 | /* | |
1127 | * Release the dependent linkage. This is much simpler than | |
1128 | * configfs_depend_item() because we know that that the client driver is | |
1129 | * pinned, thus the subsystem is pinned, and therefore configfs is pinned. | |
1130 | */ | |
1131 | void configfs_undepend_item(struct configfs_subsystem *subsys, | |
1132 | struct config_item *target) | |
1133 | { | |
1134 | struct configfs_dirent *sd; | |
1135 | ||
1136 | /* | |
420118ca LR |
1137 | * Since we can trust everything is pinned, we just need |
1138 | * configfs_dirent_lock. | |
631d1feb | 1139 | */ |
420118ca | 1140 | spin_lock(&configfs_dirent_lock); |
631d1feb JB |
1141 | |
1142 | sd = target->ci_dentry->d_fsdata; | |
1143 | BUG_ON(sd->s_dependent_count < 1); | |
1144 | ||
1145 | sd->s_dependent_count -= 1; | |
1146 | ||
1147 | /* | |
1148 | * After this unlock, we cannot trust the item to stay alive! | |
1149 | * DO NOT REFERENCE item after this unlock. | |
1150 | */ | |
420118ca | 1151 | spin_unlock(&configfs_dirent_lock); |
631d1feb JB |
1152 | } |
1153 | EXPORT_SYMBOL(configfs_undepend_item); | |
7063fbf2 | 1154 | |
18bb1db3 | 1155 | static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) |
7063fbf2 | 1156 | { |
a6795e9e JB |
1157 | int ret = 0; |
1158 | int module_got = 0; | |
1159 | struct config_group *group = NULL; | |
1160 | struct config_item *item = NULL; | |
7063fbf2 JB |
1161 | struct config_item *parent_item; |
1162 | struct configfs_subsystem *subsys; | |
1163 | struct configfs_dirent *sd; | |
1164 | struct config_item_type *type; | |
70526b67 | 1165 | struct module *subsys_owner = NULL, *new_item_owner = NULL; |
7063fbf2 JB |
1166 | char *name; |
1167 | ||
7063fbf2 | 1168 | sd = dentry->d_parent->d_fsdata; |
2a109f2a LR |
1169 | |
1170 | /* | |
1171 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
1172 | * being attached | |
1173 | */ | |
1174 | if (!configfs_dirent_is_ready(sd)) { | |
1175 | ret = -ENOENT; | |
1176 | goto out; | |
1177 | } | |
1178 | ||
84efad1a JB |
1179 | if (!(sd->s_type & CONFIGFS_USET_DIR)) { |
1180 | ret = -EPERM; | |
1181 | goto out; | |
1182 | } | |
7063fbf2 | 1183 | |
84efad1a | 1184 | /* Get a working ref for the duration of this function */ |
7063fbf2 JB |
1185 | parent_item = configfs_get_config_item(dentry->d_parent); |
1186 | type = parent_item->ci_type; | |
1187 | subsys = to_config_group(parent_item)->cg_subsys; | |
1188 | BUG_ON(!subsys); | |
1189 | ||
1190 | if (!type || !type->ct_group_ops || | |
1191 | (!type->ct_group_ops->make_group && | |
1192 | !type->ct_group_ops->make_item)) { | |
84efad1a JB |
1193 | ret = -EPERM; /* Lack-of-mkdir returns -EPERM */ |
1194 | goto out_put; | |
7063fbf2 JB |
1195 | } |
1196 | ||
70526b67 JB |
1197 | /* |
1198 | * The subsystem may belong to a different module than the item | |
1199 | * being created. We don't want to safely pin the new item but | |
1200 | * fail to pin the subsystem it sits under. | |
1201 | */ | |
1202 | if (!subsys->su_group.cg_item.ci_type) { | |
1203 | ret = -EINVAL; | |
1204 | goto out_put; | |
1205 | } | |
1206 | subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; | |
1207 | if (!try_module_get(subsys_owner)) { | |
1208 | ret = -EINVAL; | |
1209 | goto out_put; | |
1210 | } | |
1211 | ||
7063fbf2 JB |
1212 | name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL); |
1213 | if (!name) { | |
84efad1a | 1214 | ret = -ENOMEM; |
70526b67 | 1215 | goto out_subsys_put; |
7063fbf2 | 1216 | } |
84efad1a | 1217 | |
7063fbf2 JB |
1218 | snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name); |
1219 | ||
e6bd07ae | 1220 | mutex_lock(&subsys->su_mutex); |
7063fbf2 | 1221 | if (type->ct_group_ops->make_group) { |
f89ab861 | 1222 | group = type->ct_group_ops->make_group(to_config_group(parent_item), name); |
a6795e9e JB |
1223 | if (!group) |
1224 | group = ERR_PTR(-ENOMEM); | |
1225 | if (!IS_ERR(group)) { | |
7063fbf2 JB |
1226 | link_group(to_config_group(parent_item), group); |
1227 | item = &group->cg_item; | |
a6795e9e JB |
1228 | } else |
1229 | ret = PTR_ERR(group); | |
7063fbf2 | 1230 | } else { |
f89ab861 | 1231 | item = type->ct_group_ops->make_item(to_config_group(parent_item), name); |
a6795e9e JB |
1232 | if (!item) |
1233 | item = ERR_PTR(-ENOMEM); | |
1234 | if (!IS_ERR(item)) | |
7063fbf2 | 1235 | link_obj(parent_item, item); |
a6795e9e JB |
1236 | else |
1237 | ret = PTR_ERR(item); | |
7063fbf2 | 1238 | } |
e6bd07ae | 1239 | mutex_unlock(&subsys->su_mutex); |
7063fbf2 JB |
1240 | |
1241 | kfree(name); | |
a6795e9e | 1242 | if (ret) { |
eed7a0db | 1243 | /* |
dacdd0e0 | 1244 | * If ret != 0, then link_obj() was never called. |
eed7a0db JB |
1245 | * There are no extra references to clean up. |
1246 | */ | |
70526b67 | 1247 | goto out_subsys_put; |
7063fbf2 JB |
1248 | } |
1249 | ||
eed7a0db JB |
1250 | /* |
1251 | * link_obj() has been called (via link_group() for groups). | |
1252 | * From here on out, errors must clean that up. | |
1253 | */ | |
1254 | ||
7063fbf2 | 1255 | type = item->ci_type; |
eed7a0db JB |
1256 | if (!type) { |
1257 | ret = -EINVAL; | |
1258 | goto out_unlink; | |
1259 | } | |
7063fbf2 | 1260 | |
70526b67 JB |
1261 | new_item_owner = type->ct_owner; |
1262 | if (!try_module_get(new_item_owner)) { | |
eed7a0db JB |
1263 | ret = -EINVAL; |
1264 | goto out_unlink; | |
1265 | } | |
7063fbf2 | 1266 | |
eed7a0db JB |
1267 | /* |
1268 | * I hate doing it this way, but if there is | |
1269 | * an error, module_put() probably should | |
1270 | * happen after any cleanup. | |
1271 | */ | |
1272 | module_got = 1; | |
1273 | ||
6d8344ba LR |
1274 | /* |
1275 | * Make racing rmdir() fail if it did not tag parent with | |
1276 | * CONFIGFS_USET_DROPPING | |
1277 | * Note: if CONFIGFS_USET_DROPPING is already set, attach_group() will | |
1278 | * fail and let rmdir() terminate correctly | |
1279 | */ | |
1280 | spin_lock(&configfs_dirent_lock); | |
1281 | /* This will make configfs_detach_prep() fail */ | |
1282 | sd->s_type |= CONFIGFS_USET_IN_MKDIR; | |
1283 | spin_unlock(&configfs_dirent_lock); | |
1284 | ||
eed7a0db JB |
1285 | if (group) |
1286 | ret = configfs_attach_group(parent_item, item, dentry); | |
1287 | else | |
1288 | ret = configfs_attach_item(parent_item, item, dentry); | |
1289 | ||
6d8344ba LR |
1290 | spin_lock(&configfs_dirent_lock); |
1291 | sd->s_type &= ~CONFIGFS_USET_IN_MKDIR; | |
2a109f2a LR |
1292 | if (!ret) |
1293 | configfs_dir_set_ready(dentry->d_fsdata); | |
6d8344ba LR |
1294 | spin_unlock(&configfs_dirent_lock); |
1295 | ||
eed7a0db JB |
1296 | out_unlink: |
1297 | if (ret) { | |
1298 | /* Tear down everything we built up */ | |
e6bd07ae | 1299 | mutex_lock(&subsys->su_mutex); |
299894cc JB |
1300 | |
1301 | client_disconnect_notify(parent_item, item); | |
eed7a0db JB |
1302 | if (group) |
1303 | unlink_group(group); | |
1304 | else | |
1305 | unlink_obj(item); | |
1306 | client_drop_item(parent_item, item); | |
299894cc | 1307 | |
e6bd07ae | 1308 | mutex_unlock(&subsys->su_mutex); |
eed7a0db JB |
1309 | |
1310 | if (module_got) | |
70526b67 | 1311 | module_put(new_item_owner); |
7063fbf2 JB |
1312 | } |
1313 | ||
70526b67 JB |
1314 | out_subsys_put: |
1315 | if (ret) | |
1316 | module_put(subsys_owner); | |
1317 | ||
84efad1a JB |
1318 | out_put: |
1319 | /* | |
eed7a0db JB |
1320 | * link_obj()/link_group() took a reference from child->parent, |
1321 | * so the parent is safely pinned. We can drop our working | |
1322 | * reference. | |
84efad1a JB |
1323 | */ |
1324 | config_item_put(parent_item); | |
1325 | ||
1326 | out: | |
7063fbf2 JB |
1327 | return ret; |
1328 | } | |
1329 | ||
1330 | static int configfs_rmdir(struct inode *dir, struct dentry *dentry) | |
1331 | { | |
1332 | struct config_item *parent_item; | |
1333 | struct config_item *item; | |
1334 | struct configfs_subsystem *subsys; | |
1335 | struct configfs_dirent *sd; | |
70526b67 | 1336 | struct module *subsys_owner = NULL, *dead_item_owner = NULL; |
7063fbf2 JB |
1337 | int ret; |
1338 | ||
7063fbf2 JB |
1339 | sd = dentry->d_fsdata; |
1340 | if (sd->s_type & CONFIGFS_USET_DEFAULT) | |
1341 | return -EPERM; | |
1342 | ||
84efad1a | 1343 | /* Get a working ref until we have the child */ |
7063fbf2 JB |
1344 | parent_item = configfs_get_config_item(dentry->d_parent); |
1345 | subsys = to_config_group(parent_item)->cg_subsys; | |
1346 | BUG_ON(!subsys); | |
1347 | ||
1348 | if (!parent_item->ci_type) { | |
1349 | config_item_put(parent_item); | |
1350 | return -EINVAL; | |
1351 | } | |
1352 | ||
70526b67 JB |
1353 | /* configfs_mkdir() shouldn't have allowed this */ |
1354 | BUG_ON(!subsys->su_group.cg_item.ci_type); | |
1355 | subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; | |
1356 | ||
9a73d78c LR |
1357 | /* |
1358 | * Ensure that no racing symlink() will make detach_prep() fail while | |
1359 | * the new link is temporarily attached | |
1360 | */ | |
6d8344ba LR |
1361 | do { |
1362 | struct mutex *wait_mutex; | |
1363 | ||
de6bf18e LR |
1364 | mutex_lock(&configfs_symlink_mutex); |
1365 | spin_lock(&configfs_dirent_lock); | |
420118ca LR |
1366 | /* |
1367 | * Here's where we check for dependents. We're protected by | |
1368 | * configfs_dirent_lock. | |
1369 | * If no dependent, atomically tag the item as dropping. | |
1370 | */ | |
1371 | ret = sd->s_dependent_count ? -EBUSY : 0; | |
1372 | if (!ret) { | |
1373 | ret = configfs_detach_prep(dentry, &wait_mutex); | |
1374 | if (ret) | |
1375 | configfs_detach_rollback(dentry); | |
1376 | } | |
de6bf18e LR |
1377 | spin_unlock(&configfs_dirent_lock); |
1378 | mutex_unlock(&configfs_symlink_mutex); | |
1379 | ||
1380 | if (ret) { | |
6d8344ba LR |
1381 | if (ret != -EAGAIN) { |
1382 | config_item_put(parent_item); | |
1383 | return ret; | |
1384 | } | |
1385 | ||
1386 | /* Wait until the racing operation terminates */ | |
1387 | mutex_lock(wait_mutex); | |
1388 | mutex_unlock(wait_mutex); | |
6d8344ba LR |
1389 | } |
1390 | } while (ret == -EAGAIN); | |
7063fbf2 | 1391 | |
84efad1a | 1392 | /* Get a working ref for the duration of this function */ |
7063fbf2 JB |
1393 | item = configfs_get_config_item(dentry); |
1394 | ||
1395 | /* Drop reference from above, item already holds one. */ | |
1396 | config_item_put(parent_item); | |
1397 | ||
1398 | if (item->ci_type) | |
70526b67 | 1399 | dead_item_owner = item->ci_type->ct_owner; |
7063fbf2 JB |
1400 | |
1401 | if (sd->s_type & CONFIGFS_USET_DIR) { | |
1402 | configfs_detach_group(item); | |
1403 | ||
e6bd07ae | 1404 | mutex_lock(&subsys->su_mutex); |
299894cc | 1405 | client_disconnect_notify(parent_item, item); |
7063fbf2 JB |
1406 | unlink_group(to_config_group(item)); |
1407 | } else { | |
1408 | configfs_detach_item(item); | |
1409 | ||
e6bd07ae | 1410 | mutex_lock(&subsys->su_mutex); |
299894cc | 1411 | client_disconnect_notify(parent_item, item); |
7063fbf2 JB |
1412 | unlink_obj(item); |
1413 | } | |
1414 | ||
1415 | client_drop_item(parent_item, item); | |
e6bd07ae | 1416 | mutex_unlock(&subsys->su_mutex); |
7063fbf2 JB |
1417 | |
1418 | /* Drop our reference from above */ | |
1419 | config_item_put(item); | |
1420 | ||
70526b67 JB |
1421 | module_put(dead_item_owner); |
1422 | module_put(subsys_owner); | |
7063fbf2 JB |
1423 | |
1424 | return 0; | |
1425 | } | |
1426 | ||
754661f1 | 1427 | const struct inode_operations configfs_dir_inode_operations = { |
7063fbf2 JB |
1428 | .mkdir = configfs_mkdir, |
1429 | .rmdir = configfs_rmdir, | |
1430 | .symlink = configfs_symlink, | |
1431 | .unlink = configfs_unlink, | |
1432 | .lookup = configfs_lookup, | |
3d0f89bb | 1433 | .setattr = configfs_setattr, |
7063fbf2 JB |
1434 | }; |
1435 | ||
81d44ed1 AV |
1436 | const struct inode_operations configfs_root_inode_operations = { |
1437 | .lookup = configfs_lookup, | |
1438 | .setattr = configfs_setattr, | |
1439 | }; | |
1440 | ||
7063fbf2 JB |
1441 | #if 0 |
1442 | int configfs_rename_dir(struct config_item * item, const char *new_name) | |
1443 | { | |
1444 | int error = 0; | |
1445 | struct dentry * new_dentry, * parent; | |
1446 | ||
1447 | if (!strcmp(config_item_name(item), new_name)) | |
1448 | return -EINVAL; | |
1449 | ||
1450 | if (!item->parent) | |
1451 | return -EINVAL; | |
1452 | ||
1453 | down_write(&configfs_rename_sem); | |
1454 | parent = item->parent->dentry; | |
1455 | ||
2b0143b5 | 1456 | mutex_lock(&d_inode(parent)->i_mutex); |
7063fbf2 JB |
1457 | |
1458 | new_dentry = lookup_one_len(new_name, parent, strlen(new_name)); | |
1459 | if (!IS_ERR(new_dentry)) { | |
2b0143b5 | 1460 | if (d_really_is_negative(new_dentry)) { |
7063fbf2 JB |
1461 | error = config_item_set_name(item, "%s", new_name); |
1462 | if (!error) { | |
1463 | d_add(new_dentry, NULL); | |
1464 | d_move(item->dentry, new_dentry); | |
1465 | } | |
1466 | else | |
1467 | d_delete(new_dentry); | |
1468 | } else | |
1469 | error = -EEXIST; | |
1470 | dput(new_dentry); | |
1471 | } | |
2b0143b5 | 1472 | mutex_unlock(&d_inode(parent)->i_mutex); |
7063fbf2 JB |
1473 | up_write(&configfs_rename_sem); |
1474 | ||
1475 | return error; | |
1476 | } | |
1477 | #endif | |
1478 | ||
1479 | static int configfs_dir_open(struct inode *inode, struct file *file) | |
1480 | { | |
867fa491 | 1481 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 | 1482 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
2a109f2a | 1483 | int err; |
7063fbf2 | 1484 | |
2b0143b5 | 1485 | mutex_lock(&d_inode(dentry)->i_mutex); |
2a109f2a LR |
1486 | /* |
1487 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
1488 | * being attached | |
1489 | */ | |
1490 | err = -ENOENT; | |
1491 | if (configfs_dirent_is_ready(parent_sd)) { | |
420118ca | 1492 | file->private_data = configfs_new_dirent(parent_sd, NULL, 0); |
2a109f2a LR |
1493 | if (IS_ERR(file->private_data)) |
1494 | err = PTR_ERR(file->private_data); | |
1495 | else | |
1496 | err = 0; | |
1497 | } | |
2b0143b5 | 1498 | mutex_unlock(&d_inode(dentry)->i_mutex); |
7063fbf2 | 1499 | |
2a109f2a | 1500 | return err; |
7063fbf2 JB |
1501 | } |
1502 | ||
1503 | static int configfs_dir_close(struct inode *inode, struct file *file) | |
1504 | { | |
867fa491 | 1505 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 JB |
1506 | struct configfs_dirent * cursor = file->private_data; |
1507 | ||
2b0143b5 | 1508 | mutex_lock(&d_inode(dentry)->i_mutex); |
6f610764 | 1509 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 1510 | list_del_init(&cursor->s_sibling); |
6f610764 | 1511 | spin_unlock(&configfs_dirent_lock); |
2b0143b5 | 1512 | mutex_unlock(&d_inode(dentry)->i_mutex); |
7063fbf2 JB |
1513 | |
1514 | release_configfs_dirent(cursor); | |
1515 | ||
1516 | return 0; | |
1517 | } | |
1518 | ||
1519 | /* Relationship between s_mode and the DT_xxx types */ | |
1520 | static inline unsigned char dt_type(struct configfs_dirent *sd) | |
1521 | { | |
1522 | return (sd->s_mode >> 12) & 15; | |
1523 | } | |
1524 | ||
52018855 | 1525 | static int configfs_readdir(struct file *file, struct dir_context *ctx) |
7063fbf2 | 1526 | { |
52018855 | 1527 | struct dentry *dentry = file->f_path.dentry; |
b7c177fc | 1528 | struct super_block *sb = dentry->d_sb; |
7063fbf2 | 1529 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
52018855 | 1530 | struct configfs_dirent *cursor = file->private_data; |
7063fbf2 | 1531 | struct list_head *p, *q = &cursor->s_sibling; |
24307aa1 | 1532 | ino_t ino = 0; |
7063fbf2 | 1533 | |
52018855 AV |
1534 | if (!dir_emit_dots(file, ctx)) |
1535 | return 0; | |
1536 | if (ctx->pos == 2) { | |
1537 | spin_lock(&configfs_dirent_lock); | |
1538 | list_move(q, &parent_sd->s_children); | |
1539 | spin_unlock(&configfs_dirent_lock); | |
1540 | } | |
1541 | for (p = q->next; p != &parent_sd->s_children; p = p->next) { | |
1542 | struct configfs_dirent *next; | |
1543 | const char *name; | |
1544 | int len; | |
1545 | struct inode *inode = NULL; | |
1546 | ||
1547 | next = list_entry(p, struct configfs_dirent, s_sibling); | |
1548 | if (!next->s_element) | |
1549 | continue; | |
7063fbf2 | 1550 | |
52018855 AV |
1551 | name = configfs_get_name(next); |
1552 | len = strlen(name); | |
1553 | ||
1554 | /* | |
1555 | * We'll have a dentry and an inode for | |
1556 | * PINNED items and for open attribute | |
1557 | * files. We lock here to prevent a race | |
1558 | * with configfs_d_iput() clearing | |
1559 | * s_dentry before calling iput(). | |
1560 | * | |
1561 | * Why do we go to the trouble? If | |
1562 | * someone has an attribute file open, | |
1563 | * the inode number should match until | |
1564 | * they close it. Beyond that, we don't | |
1565 | * care. | |
1566 | */ | |
1567 | spin_lock(&configfs_dirent_lock); | |
1568 | dentry = next->s_dentry; | |
1569 | if (dentry) | |
2b0143b5 | 1570 | inode = d_inode(dentry); |
52018855 AV |
1571 | if (inode) |
1572 | ino = inode->i_ino; | |
1573 | spin_unlock(&configfs_dirent_lock); | |
1574 | if (!inode) | |
1575 | ino = iunique(sb, 2); | |
7063fbf2 | 1576 | |
52018855 AV |
1577 | if (!dir_emit(ctx, name, len, ino, dt_type(next))) |
1578 | return 0; | |
7063fbf2 | 1579 | |
52018855 AV |
1580 | spin_lock(&configfs_dirent_lock); |
1581 | list_move(q, p); | |
1582 | spin_unlock(&configfs_dirent_lock); | |
1583 | p = q; | |
1584 | ctx->pos++; | |
7063fbf2 JB |
1585 | } |
1586 | return 0; | |
1587 | } | |
1588 | ||
965c8e59 | 1589 | static loff_t configfs_dir_lseek(struct file *file, loff_t offset, int whence) |
7063fbf2 | 1590 | { |
867fa491 | 1591 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 | 1592 | |
2b0143b5 | 1593 | mutex_lock(&d_inode(dentry)->i_mutex); |
965c8e59 | 1594 | switch (whence) { |
7063fbf2 JB |
1595 | case 1: |
1596 | offset += file->f_pos; | |
1597 | case 0: | |
1598 | if (offset >= 0) | |
1599 | break; | |
1600 | default: | |
2b0143b5 | 1601 | mutex_unlock(&d_inode(dentry)->i_mutex); |
7063fbf2 JB |
1602 | return -EINVAL; |
1603 | } | |
1604 | if (offset != file->f_pos) { | |
1605 | file->f_pos = offset; | |
1606 | if (file->f_pos >= 2) { | |
1607 | struct configfs_dirent *sd = dentry->d_fsdata; | |
1608 | struct configfs_dirent *cursor = file->private_data; | |
1609 | struct list_head *p; | |
1610 | loff_t n = file->f_pos - 2; | |
1611 | ||
6f610764 | 1612 | spin_lock(&configfs_dirent_lock); |
7063fbf2 JB |
1613 | list_del(&cursor->s_sibling); |
1614 | p = sd->s_children.next; | |
1615 | while (n && p != &sd->s_children) { | |
1616 | struct configfs_dirent *next; | |
1617 | next = list_entry(p, struct configfs_dirent, | |
1618 | s_sibling); | |
1619 | if (next->s_element) | |
1620 | n--; | |
1621 | p = p->next; | |
1622 | } | |
1623 | list_add_tail(&cursor->s_sibling, p); | |
6f610764 | 1624 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
1625 | } |
1626 | } | |
2b0143b5 | 1627 | mutex_unlock(&d_inode(dentry)->i_mutex); |
7063fbf2 JB |
1628 | return offset; |
1629 | } | |
1630 | ||
4b6f5d20 | 1631 | const struct file_operations configfs_dir_operations = { |
7063fbf2 JB |
1632 | .open = configfs_dir_open, |
1633 | .release = configfs_dir_close, | |
1634 | .llseek = configfs_dir_lseek, | |
1635 | .read = generic_read_dir, | |
52018855 | 1636 | .iterate = configfs_readdir, |
7063fbf2 JB |
1637 | }; |
1638 | ||
1639 | int configfs_register_subsystem(struct configfs_subsystem *subsys) | |
1640 | { | |
1641 | int err; | |
1642 | struct config_group *group = &subsys->su_group; | |
7063fbf2 | 1643 | struct dentry *dentry; |
b7c177fc | 1644 | struct dentry *root; |
7063fbf2 JB |
1645 | struct configfs_dirent *sd; |
1646 | ||
2a152ad3 AV |
1647 | root = configfs_pin_fs(); |
1648 | if (IS_ERR(root)) | |
1649 | return PTR_ERR(root); | |
7063fbf2 JB |
1650 | |
1651 | if (!group->cg_item.ci_name) | |
1652 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
1653 | ||
b7c177fc | 1654 | sd = root->d_fsdata; |
7063fbf2 JB |
1655 | link_group(to_config_group(sd->s_element), group); |
1656 | ||
2b0143b5 | 1657 | mutex_lock_nested(&d_inode(root)->i_mutex, I_MUTEX_PARENT); |
7063fbf2 | 1658 | |
7063fbf2 | 1659 | err = -ENOMEM; |
ec193cf5 | 1660 | dentry = d_alloc_name(root, group->cg_item.ci_name); |
afdf04ea JB |
1661 | if (dentry) { |
1662 | d_add(dentry, NULL); | |
7063fbf2 | 1663 | |
afdf04ea JB |
1664 | err = configfs_attach_group(sd->s_element, &group->cg_item, |
1665 | dentry); | |
1666 | if (err) { | |
2b0143b5 | 1667 | BUG_ON(d_inode(dentry)); |
df7f9967 | 1668 | d_drop(dentry); |
afdf04ea | 1669 | dput(dentry); |
2a109f2a LR |
1670 | } else { |
1671 | spin_lock(&configfs_dirent_lock); | |
1672 | configfs_dir_set_ready(dentry->d_fsdata); | |
1673 | spin_unlock(&configfs_dirent_lock); | |
afdf04ea JB |
1674 | } |
1675 | } | |
7063fbf2 | 1676 | |
2b0143b5 | 1677 | mutex_unlock(&d_inode(root)->i_mutex); |
7063fbf2 | 1678 | |
afdf04ea JB |
1679 | if (err) { |
1680 | unlink_group(group); | |
1681 | configfs_release_fs(); | |
7063fbf2 JB |
1682 | } |
1683 | ||
1684 | return err; | |
1685 | } | |
1686 | ||
1687 | void configfs_unregister_subsystem(struct configfs_subsystem *subsys) | |
1688 | { | |
1689 | struct config_group *group = &subsys->su_group; | |
1690 | struct dentry *dentry = group->cg_item.ci_dentry; | |
b7c177fc | 1691 | struct dentry *root = dentry->d_sb->s_root; |
7063fbf2 | 1692 | |
b7c177fc | 1693 | if (dentry->d_parent != root) { |
1d88aa44 | 1694 | pr_err("Tried to unregister non-subsystem!\n"); |
7063fbf2 JB |
1695 | return; |
1696 | } | |
1697 | ||
2b0143b5 | 1698 | mutex_lock_nested(&d_inode(root)->i_mutex, |
55ed1602 | 1699 | I_MUTEX_PARENT); |
2b0143b5 | 1700 | mutex_lock_nested(&d_inode(dentry)->i_mutex, I_MUTEX_CHILD); |
9a73d78c | 1701 | mutex_lock(&configfs_symlink_mutex); |
b3e76af8 | 1702 | spin_lock(&configfs_dirent_lock); |
6d8344ba | 1703 | if (configfs_detach_prep(dentry, NULL)) { |
1d88aa44 | 1704 | pr_err("Tried to unregister non-empty subsystem!\n"); |
7063fbf2 | 1705 | } |
b3e76af8 | 1706 | spin_unlock(&configfs_dirent_lock); |
9a73d78c | 1707 | mutex_unlock(&configfs_symlink_mutex); |
7063fbf2 | 1708 | configfs_detach_group(&group->cg_item); |
2b0143b5 | 1709 | d_inode(dentry)->i_flags |= S_DEAD; |
d83c49f3 | 1710 | dont_mount(dentry); |
2b0143b5 | 1711 | mutex_unlock(&d_inode(dentry)->i_mutex); |
7063fbf2 JB |
1712 | |
1713 | d_delete(dentry); | |
1714 | ||
2b0143b5 | 1715 | mutex_unlock(&d_inode(root)->i_mutex); |
7063fbf2 JB |
1716 | |
1717 | dput(dentry); | |
1718 | ||
1719 | unlink_group(group); | |
1720 | configfs_release_fs(); | |
1721 | } | |
1722 | ||
1723 | EXPORT_SYMBOL(configfs_register_subsystem); | |
1724 | EXPORT_SYMBOL(configfs_unregister_subsystem); |