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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 | ||
243 | static int init_dir(struct inode * inode) | |
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 | return 0; |
251 | } | |
252 | ||
ce8d2cdf | 253 | static int configfs_init_file(struct inode * inode) |
7063fbf2 JB |
254 | { |
255 | inode->i_size = PAGE_SIZE; | |
256 | inode->i_fop = &configfs_file_operations; | |
257 | return 0; | |
258 | } | |
259 | ||
260 | static int init_symlink(struct inode * inode) | |
261 | { | |
262 | inode->i_op = &configfs_symlink_inode_operations; | |
263 | return 0; | |
264 | } | |
265 | ||
0dd6c08a | 266 | static int create_dir(struct config_item *k, struct dentry *d) |
7063fbf2 JB |
267 | { |
268 | int error; | |
269 | umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; | |
0dd6c08a AV |
270 | struct dentry *p = d->d_parent; |
271 | ||
272 | BUG_ON(!k); | |
7063fbf2 | 273 | |
b4c98f62 JB |
274 | error = configfs_dirent_exists(p->d_fsdata, d->d_name.name); |
275 | if (!error) | |
276 | error = configfs_make_dirent(p->d_fsdata, d, k, mode, | |
2a109f2a | 277 | CONFIGFS_DIR | CONFIGFS_USET_CREATING); |
7063fbf2 | 278 | if (!error) { |
e74cc06d | 279 | configfs_set_dir_dirent_depth(p->d_fsdata, d->d_fsdata); |
3d0f89bb | 280 | error = configfs_create(d, mode, init_dir); |
7063fbf2 | 281 | if (!error) { |
d8c76e6f | 282 | inc_nlink(p->d_inode); |
3d0f89bb JB |
283 | } else { |
284 | struct configfs_dirent *sd = d->d_fsdata; | |
285 | if (sd) { | |
6f610764 | 286 | spin_lock(&configfs_dirent_lock); |
3d0f89bb | 287 | list_del_init(&sd->s_sibling); |
6f610764 | 288 | spin_unlock(&configfs_dirent_lock); |
3d0f89bb JB |
289 | configfs_put(sd); |
290 | } | |
7063fbf2 JB |
291 | } |
292 | } | |
293 | return error; | |
294 | } | |
295 | ||
296 | ||
297 | /** | |
298 | * configfs_create_dir - create a directory for an config_item. | |
299 | * @item: config_itemwe're creating directory for. | |
300 | * @dentry: config_item's dentry. | |
2a109f2a LR |
301 | * |
302 | * Note: user-created entries won't be allowed under this new directory | |
303 | * until it is validated by configfs_dir_set_ready() | |
7063fbf2 JB |
304 | */ |
305 | ||
306 | static int configfs_create_dir(struct config_item * item, struct dentry *dentry) | |
307 | { | |
0dd6c08a | 308 | int error = create_dir(item, dentry); |
7063fbf2 JB |
309 | if (!error) |
310 | item->ci_dentry = dentry; | |
311 | return error; | |
312 | } | |
313 | ||
2a109f2a LR |
314 | /* |
315 | * Allow userspace to create new entries under a new directory created with | |
316 | * configfs_create_dir(), and under all of its chidlren directories recursively. | |
317 | * @sd configfs_dirent of the new directory to validate | |
318 | * | |
319 | * Caller must hold configfs_dirent_lock. | |
320 | */ | |
321 | static void configfs_dir_set_ready(struct configfs_dirent *sd) | |
322 | { | |
323 | struct configfs_dirent *child_sd; | |
324 | ||
325 | sd->s_type &= ~CONFIGFS_USET_CREATING; | |
326 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) | |
327 | if (child_sd->s_type & CONFIGFS_USET_CREATING) | |
328 | configfs_dir_set_ready(child_sd); | |
329 | } | |
330 | ||
331 | /* | |
332 | * Check that a directory does not belong to a directory hierarchy being | |
333 | * attached and not validated yet. | |
334 | * @sd configfs_dirent of the directory to check | |
335 | * | |
336 | * @return non-zero iff the directory was validated | |
337 | * | |
338 | * Note: takes configfs_dirent_lock, so the result may change from false to true | |
339 | * in two consecutive calls, but never from true to false. | |
340 | */ | |
341 | int configfs_dirent_is_ready(struct configfs_dirent *sd) | |
342 | { | |
343 | int ret; | |
344 | ||
345 | spin_lock(&configfs_dirent_lock); | |
346 | ret = !(sd->s_type & CONFIGFS_USET_CREATING); | |
347 | spin_unlock(&configfs_dirent_lock); | |
348 | ||
349 | return ret; | |
350 | } | |
351 | ||
7063fbf2 JB |
352 | int configfs_create_link(struct configfs_symlink *sl, |
353 | struct dentry *parent, | |
354 | struct dentry *dentry) | |
355 | { | |
356 | int err = 0; | |
357 | umode_t mode = S_IFLNK | S_IRWXUGO; | |
358 | ||
3d0f89bb JB |
359 | err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode, |
360 | CONFIGFS_ITEM_LINK); | |
7063fbf2 | 361 | if (!err) { |
3d0f89bb | 362 | err = configfs_create(dentry, mode, init_symlink); |
fbc8d4c0 | 363 | if (err) { |
3d0f89bb JB |
364 | struct configfs_dirent *sd = dentry->d_fsdata; |
365 | if (sd) { | |
6f610764 | 366 | spin_lock(&configfs_dirent_lock); |
3d0f89bb | 367 | list_del_init(&sd->s_sibling); |
6f610764 | 368 | spin_unlock(&configfs_dirent_lock); |
3d0f89bb JB |
369 | configfs_put(sd); |
370 | } | |
371 | } | |
7063fbf2 JB |
372 | } |
373 | return err; | |
374 | } | |
375 | ||
376 | static void remove_dir(struct dentry * d) | |
377 | { | |
378 | struct dentry * parent = dget(d->d_parent); | |
379 | struct configfs_dirent * sd; | |
380 | ||
381 | sd = d->d_fsdata; | |
6f610764 | 382 | spin_lock(&configfs_dirent_lock); |
e7515d06 | 383 | list_del_init(&sd->s_sibling); |
6f610764 | 384 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
385 | configfs_put(sd); |
386 | if (d->d_inode) | |
387 | simple_rmdir(parent->d_inode,d); | |
388 | ||
c75e2475 | 389 | pr_debug(" o %s removing done (%d)\n",d->d_name.name, d_count(d)); |
7063fbf2 JB |
390 | |
391 | dput(parent); | |
392 | } | |
393 | ||
394 | /** | |
395 | * configfs_remove_dir - remove an config_item's directory. | |
396 | * @item: config_item we're removing. | |
397 | * | |
398 | * The only thing special about this is that we remove any files in | |
399 | * the directory before we remove the directory, and we've inlined | |
400 | * what used to be configfs_rmdir() below, instead of calling separately. | |
2e2ce171 LR |
401 | * |
402 | * Caller holds the mutex of the item's inode | |
7063fbf2 JB |
403 | */ |
404 | ||
405 | static void configfs_remove_dir(struct config_item * item) | |
406 | { | |
407 | struct dentry * dentry = dget(item->ci_dentry); | |
408 | ||
409 | if (!dentry) | |
410 | return; | |
411 | ||
412 | remove_dir(dentry); | |
413 | /** | |
414 | * Drop reference from dget() on entrance. | |
415 | */ | |
416 | dput(dentry); | |
417 | } | |
418 | ||
419 | ||
420 | /* attaches attribute's configfs_dirent to the dentry corresponding to the | |
421 | * attribute file | |
422 | */ | |
423 | static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry) | |
424 | { | |
425 | struct configfs_attribute * attr = sd->s_element; | |
426 | int error; | |
427 | ||
76ae281f | 428 | spin_lock(&configfs_dirent_lock); |
3d0f89bb JB |
429 | dentry->d_fsdata = configfs_get(sd); |
430 | sd->s_dentry = dentry; | |
76ae281f JB |
431 | spin_unlock(&configfs_dirent_lock); |
432 | ||
ce8d2cdf DH |
433 | error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG, |
434 | configfs_init_file); | |
3d0f89bb JB |
435 | if (error) { |
436 | configfs_put(sd); | |
7063fbf2 | 437 | return error; |
3d0f89bb | 438 | } |
7063fbf2 | 439 | |
7063fbf2 JB |
440 | d_rehash(dentry); |
441 | ||
442 | return 0; | |
443 | } | |
444 | ||
445 | static struct dentry * configfs_lookup(struct inode *dir, | |
446 | struct dentry *dentry, | |
00cd8dd3 | 447 | unsigned int flags) |
7063fbf2 JB |
448 | { |
449 | struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata; | |
450 | struct configfs_dirent * sd; | |
451 | int found = 0; | |
2a109f2a LR |
452 | int err; |
453 | ||
454 | /* | |
455 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
456 | * being attached | |
457 | * | |
458 | * This forbids userspace to read/write attributes of items which may | |
459 | * not complete their initialization, since the dentries of the | |
460 | * attributes won't be instantiated. | |
461 | */ | |
462 | err = -ENOENT; | |
463 | if (!configfs_dirent_is_ready(parent_sd)) | |
464 | goto out; | |
7063fbf2 JB |
465 | |
466 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
467 | if (sd->s_type & CONFIGFS_NOT_PINNED) { | |
468 | const unsigned char * name = configfs_get_name(sd); | |
469 | ||
470 | if (strcmp(name, dentry->d_name.name)) | |
471 | continue; | |
472 | ||
473 | found = 1; | |
474 | err = configfs_attach_attr(sd, dentry); | |
475 | break; | |
476 | } | |
477 | } | |
478 | ||
479 | if (!found) { | |
480 | /* | |
481 | * If it doesn't exist and it isn't a NOT_PINNED item, | |
482 | * it must be negative. | |
483 | */ | |
fbc8d4c0 NP |
484 | if (dentry->d_name.len > NAME_MAX) |
485 | return ERR_PTR(-ENAMETOOLONG); | |
fbc8d4c0 NP |
486 | d_add(dentry, NULL); |
487 | return NULL; | |
7063fbf2 JB |
488 | } |
489 | ||
2a109f2a | 490 | out: |
7063fbf2 JB |
491 | return ERR_PTR(err); |
492 | } | |
493 | ||
494 | /* | |
495 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are | |
b3e76af8 LR |
496 | * attributes and are removed by rmdir(). We recurse, setting |
497 | * CONFIGFS_USET_DROPPING on all children that are candidates for | |
498 | * default detach. | |
499 | * If there is an error, the caller will reset the flags via | |
500 | * configfs_detach_rollback(). | |
7063fbf2 | 501 | */ |
6d8344ba | 502 | static int configfs_detach_prep(struct dentry *dentry, struct mutex **wait_mutex) |
7063fbf2 JB |
503 | { |
504 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
505 | struct configfs_dirent *sd; | |
506 | int ret; | |
507 | ||
4768e9b1 LR |
508 | /* Mark that we're trying to drop the group */ |
509 | parent_sd->s_type |= CONFIGFS_USET_DROPPING; | |
510 | ||
7063fbf2 JB |
511 | ret = -EBUSY; |
512 | if (!list_empty(&parent_sd->s_links)) | |
513 | goto out; | |
514 | ||
515 | ret = 0; | |
516 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
99cefda4 LR |
517 | if (!sd->s_element || |
518 | (sd->s_type & CONFIGFS_NOT_PINNED)) | |
7063fbf2 JB |
519 | continue; |
520 | if (sd->s_type & CONFIGFS_USET_DEFAULT) { | |
6d8344ba LR |
521 | /* Abort if racing with mkdir() */ |
522 | if (sd->s_type & CONFIGFS_USET_IN_MKDIR) { | |
523 | if (wait_mutex) | |
524 | *wait_mutex = &sd->s_dentry->d_inode->i_mutex; | |
525 | return -EAGAIN; | |
526 | } | |
7063fbf2 | 527 | |
631d1feb JB |
528 | /* |
529 | * Yup, recursive. If there's a problem, blame | |
530 | * deep nesting of default_groups | |
531 | */ | |
6d8344ba | 532 | ret = configfs_detach_prep(sd->s_dentry, wait_mutex); |
7063fbf2 | 533 | if (!ret) |
e7515d06 | 534 | continue; |
7063fbf2 JB |
535 | } else |
536 | ret = -ENOTEMPTY; | |
537 | ||
538 | break; | |
539 | } | |
540 | ||
541 | out: | |
542 | return ret; | |
543 | } | |
544 | ||
545 | /* | |
b3e76af8 | 546 | * Walk the tree, resetting CONFIGFS_USET_DROPPING wherever it was |
7063fbf2 JB |
547 | * set. |
548 | */ | |
549 | static void configfs_detach_rollback(struct dentry *dentry) | |
550 | { | |
551 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
552 | struct configfs_dirent *sd; | |
553 | ||
4768e9b1 LR |
554 | parent_sd->s_type &= ~CONFIGFS_USET_DROPPING; |
555 | ||
556 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) | |
557 | if (sd->s_type & CONFIGFS_USET_DEFAULT) | |
7063fbf2 | 558 | configfs_detach_rollback(sd->s_dentry); |
7063fbf2 JB |
559 | } |
560 | ||
561 | static void detach_attrs(struct config_item * item) | |
562 | { | |
563 | struct dentry * dentry = dget(item->ci_dentry); | |
564 | struct configfs_dirent * parent_sd; | |
565 | struct configfs_dirent * sd, * tmp; | |
566 | ||
567 | if (!dentry) | |
568 | return; | |
569 | ||
570 | pr_debug("configfs %s: dropping attrs for dir\n", | |
571 | dentry->d_name.name); | |
572 | ||
573 | parent_sd = dentry->d_fsdata; | |
574 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
575 | if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED)) | |
576 | continue; | |
6f610764 | 577 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 578 | list_del_init(&sd->s_sibling); |
6f610764 | 579 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
580 | configfs_drop_dentry(sd, dentry); |
581 | configfs_put(sd); | |
582 | } | |
583 | ||
584 | /** | |
585 | * Drop reference from dget() on entrance. | |
586 | */ | |
587 | dput(dentry); | |
588 | } | |
589 | ||
590 | static int populate_attrs(struct config_item *item) | |
591 | { | |
592 | struct config_item_type *t = item->ci_type; | |
593 | struct configfs_attribute *attr; | |
594 | int error = 0; | |
595 | int i; | |
596 | ||
597 | if (!t) | |
598 | return -EINVAL; | |
599 | if (t->ct_attrs) { | |
600 | for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) { | |
601 | if ((error = configfs_create_file(item, attr))) | |
602 | break; | |
603 | } | |
604 | } | |
605 | ||
606 | if (error) | |
607 | detach_attrs(item); | |
608 | ||
609 | return error; | |
610 | } | |
611 | ||
612 | static int configfs_attach_group(struct config_item *parent_item, | |
613 | struct config_item *item, | |
614 | struct dentry *dentry); | |
615 | static void configfs_detach_group(struct config_item *item); | |
616 | ||
617 | static void detach_groups(struct config_group *group) | |
618 | { | |
619 | struct dentry * dentry = dget(group->cg_item.ci_dentry); | |
620 | struct dentry *child; | |
621 | struct configfs_dirent *parent_sd; | |
622 | struct configfs_dirent *sd, *tmp; | |
623 | ||
624 | if (!dentry) | |
625 | return; | |
626 | ||
627 | parent_sd = dentry->d_fsdata; | |
628 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
629 | if (!sd->s_element || | |
630 | !(sd->s_type & CONFIGFS_USET_DEFAULT)) | |
631 | continue; | |
632 | ||
633 | child = sd->s_dentry; | |
634 | ||
b3e76af8 LR |
635 | mutex_lock(&child->d_inode->i_mutex); |
636 | ||
7063fbf2 JB |
637 | configfs_detach_group(sd->s_element); |
638 | child->d_inode->i_flags |= S_DEAD; | |
d83c49f3 | 639 | dont_mount(child); |
7063fbf2 | 640 | |
b3e76af8 | 641 | mutex_unlock(&child->d_inode->i_mutex); |
7063fbf2 JB |
642 | |
643 | d_delete(child); | |
644 | dput(child); | |
645 | } | |
646 | ||
647 | /** | |
648 | * Drop reference from dget() on entrance. | |
649 | */ | |
650 | dput(dentry); | |
651 | } | |
652 | ||
653 | /* | |
654 | * This fakes mkdir(2) on a default_groups[] entry. It | |
655 | * creates a dentry, attachs it, and then does fixup | |
656 | * on the sd->s_type. | |
657 | * | |
658 | * We could, perhaps, tweak our parent's ->mkdir for a minute and | |
659 | * try using vfs_mkdir. Just a thought. | |
660 | */ | |
661 | static int create_default_group(struct config_group *parent_group, | |
662 | struct config_group *group) | |
663 | { | |
664 | int ret; | |
7063fbf2 JB |
665 | struct configfs_dirent *sd; |
666 | /* We trust the caller holds a reference to parent */ | |
667 | struct dentry *child, *parent = parent_group->cg_item.ci_dentry; | |
668 | ||
669 | if (!group->cg_item.ci_name) | |
670 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
7063fbf2 JB |
671 | |
672 | ret = -ENOMEM; | |
ec193cf5 | 673 | child = d_alloc_name(parent, group->cg_item.ci_name); |
7063fbf2 JB |
674 | if (child) { |
675 | d_add(child, NULL); | |
676 | ||
677 | ret = configfs_attach_group(&parent_group->cg_item, | |
678 | &group->cg_item, child); | |
679 | if (!ret) { | |
680 | sd = child->d_fsdata; | |
681 | sd->s_type |= CONFIGFS_USET_DEFAULT; | |
682 | } else { | |
df7f9967 JB |
683 | BUG_ON(child->d_inode); |
684 | d_drop(child); | |
7063fbf2 JB |
685 | dput(child); |
686 | } | |
687 | } | |
688 | ||
689 | return ret; | |
690 | } | |
691 | ||
692 | static int populate_groups(struct config_group *group) | |
693 | { | |
694 | struct config_group *new_group; | |
7063fbf2 JB |
695 | int ret = 0; |
696 | int i; | |
697 | ||
cbca692c | 698 | if (group->default_groups) { |
7063fbf2 JB |
699 | for (i = 0; group->default_groups[i]; i++) { |
700 | new_group = group->default_groups[i]; | |
701 | ||
702 | ret = create_default_group(group, new_group); | |
2e2ce171 LR |
703 | if (ret) { |
704 | detach_groups(group); | |
7063fbf2 | 705 | break; |
2e2ce171 | 706 | } |
7063fbf2 | 707 | } |
7063fbf2 JB |
708 | } |
709 | ||
7063fbf2 JB |
710 | return ret; |
711 | } | |
712 | ||
713 | /* | |
714 | * All of link_obj/unlink_obj/link_group/unlink_group require that | |
e6bd07ae | 715 | * subsys->su_mutex is held. |
7063fbf2 JB |
716 | */ |
717 | ||
718 | static void unlink_obj(struct config_item *item) | |
719 | { | |
720 | struct config_group *group; | |
721 | ||
722 | group = item->ci_group; | |
723 | if (group) { | |
724 | list_del_init(&item->ci_entry); | |
725 | ||
726 | item->ci_group = NULL; | |
727 | item->ci_parent = NULL; | |
eed7a0db JB |
728 | |
729 | /* Drop the reference for ci_entry */ | |
7063fbf2 JB |
730 | config_item_put(item); |
731 | ||
eed7a0db | 732 | /* Drop the reference for ci_parent */ |
7063fbf2 JB |
733 | config_group_put(group); |
734 | } | |
735 | } | |
736 | ||
737 | static void link_obj(struct config_item *parent_item, struct config_item *item) | |
738 | { | |
eed7a0db JB |
739 | /* |
740 | * Parent seems redundant with group, but it makes certain | |
741 | * traversals much nicer. | |
742 | */ | |
7063fbf2 | 743 | item->ci_parent = parent_item; |
eed7a0db JB |
744 | |
745 | /* | |
746 | * We hold a reference on the parent for the child's ci_parent | |
747 | * link. | |
748 | */ | |
7063fbf2 JB |
749 | item->ci_group = config_group_get(to_config_group(parent_item)); |
750 | list_add_tail(&item->ci_entry, &item->ci_group->cg_children); | |
751 | ||
eed7a0db JB |
752 | /* |
753 | * We hold a reference on the child for ci_entry on the parent's | |
754 | * cg_children | |
755 | */ | |
7063fbf2 JB |
756 | config_item_get(item); |
757 | } | |
758 | ||
759 | static void unlink_group(struct config_group *group) | |
760 | { | |
761 | int i; | |
762 | struct config_group *new_group; | |
763 | ||
764 | if (group->default_groups) { | |
765 | for (i = 0; group->default_groups[i]; i++) { | |
766 | new_group = group->default_groups[i]; | |
767 | unlink_group(new_group); | |
768 | } | |
769 | } | |
770 | ||
771 | group->cg_subsys = NULL; | |
772 | unlink_obj(&group->cg_item); | |
773 | } | |
774 | ||
775 | static void link_group(struct config_group *parent_group, struct config_group *group) | |
776 | { | |
777 | int i; | |
778 | struct config_group *new_group; | |
779 | struct configfs_subsystem *subsys = NULL; /* gcc is a turd */ | |
780 | ||
781 | link_obj(&parent_group->cg_item, &group->cg_item); | |
782 | ||
783 | if (parent_group->cg_subsys) | |
784 | subsys = parent_group->cg_subsys; | |
785 | else if (configfs_is_root(&parent_group->cg_item)) | |
786 | subsys = to_configfs_subsystem(group); | |
787 | else | |
788 | BUG(); | |
789 | group->cg_subsys = subsys; | |
790 | ||
791 | if (group->default_groups) { | |
792 | for (i = 0; group->default_groups[i]; i++) { | |
793 | new_group = group->default_groups[i]; | |
794 | link_group(group, new_group); | |
795 | } | |
796 | } | |
797 | } | |
798 | ||
799 | /* | |
800 | * The goal is that configfs_attach_item() (and | |
801 | * configfs_attach_group()) can be called from either the VFS or this | |
802 | * module. That is, they assume that the items have been created, | |
803 | * the dentry allocated, and the dcache is all ready to go. | |
804 | * | |
805 | * If they fail, they must clean up after themselves as if they | |
806 | * had never been called. The caller (VFS or local function) will | |
807 | * handle cleaning up the dcache bits. | |
808 | * | |
809 | * configfs_detach_group() and configfs_detach_item() behave similarly on | |
810 | * the way out. They assume that the proper semaphores are held, they | |
811 | * clean up the configfs items, and they expect their callers will | |
812 | * handle the dcache bits. | |
813 | */ | |
814 | static int configfs_attach_item(struct config_item *parent_item, | |
815 | struct config_item *item, | |
816 | struct dentry *dentry) | |
817 | { | |
818 | int ret; | |
819 | ||
820 | ret = configfs_create_dir(item, dentry); | |
821 | if (!ret) { | |
822 | ret = populate_attrs(item); | |
823 | if (ret) { | |
2e2ce171 LR |
824 | /* |
825 | * We are going to remove an inode and its dentry but | |
826 | * the VFS may already have hit and used them. Thus, | |
827 | * we must lock them as rmdir() would. | |
828 | */ | |
829 | mutex_lock(&dentry->d_inode->i_mutex); | |
7063fbf2 | 830 | configfs_remove_dir(item); |
2e2ce171 | 831 | dentry->d_inode->i_flags |= S_DEAD; |
d83c49f3 | 832 | dont_mount(dentry); |
2e2ce171 | 833 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
834 | d_delete(dentry); |
835 | } | |
836 | } | |
837 | ||
838 | return ret; | |
839 | } | |
840 | ||
2e2ce171 | 841 | /* Caller holds the mutex of the item's inode */ |
7063fbf2 JB |
842 | static void configfs_detach_item(struct config_item *item) |
843 | { | |
844 | detach_attrs(item); | |
845 | configfs_remove_dir(item); | |
846 | } | |
847 | ||
848 | static int configfs_attach_group(struct config_item *parent_item, | |
849 | struct config_item *item, | |
850 | struct dentry *dentry) | |
851 | { | |
852 | int ret; | |
853 | struct configfs_dirent *sd; | |
854 | ||
855 | ret = configfs_attach_item(parent_item, item, dentry); | |
856 | if (!ret) { | |
857 | sd = dentry->d_fsdata; | |
858 | sd->s_type |= CONFIGFS_USET_DIR; | |
859 | ||
2e2ce171 LR |
860 | /* |
861 | * FYI, we're faking mkdir in populate_groups() | |
862 | * We must lock the group's inode to avoid races with the VFS | |
863 | * which can already hit the inode and try to add/remove entries | |
864 | * under it. | |
865 | * | |
866 | * We must also lock the inode to remove it safely in case of | |
867 | * error, as rmdir() would. | |
868 | */ | |
869 | mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); | |
e74cc06d | 870 | configfs_adjust_dir_dirent_depth_before_populate(sd); |
7063fbf2 JB |
871 | ret = populate_groups(to_config_group(item)); |
872 | if (ret) { | |
873 | configfs_detach_item(item); | |
2e2ce171 | 874 | dentry->d_inode->i_flags |= S_DEAD; |
d83c49f3 | 875 | dont_mount(dentry); |
7063fbf2 | 876 | } |
e74cc06d | 877 | configfs_adjust_dir_dirent_depth_after_populate(sd); |
2e2ce171 LR |
878 | mutex_unlock(&dentry->d_inode->i_mutex); |
879 | if (ret) | |
880 | d_delete(dentry); | |
7063fbf2 JB |
881 | } |
882 | ||
883 | return ret; | |
884 | } | |
885 | ||
2e2ce171 | 886 | /* Caller holds the mutex of the group's inode */ |
7063fbf2 JB |
887 | static void configfs_detach_group(struct config_item *item) |
888 | { | |
889 | detach_groups(to_config_group(item)); | |
890 | configfs_detach_item(item); | |
891 | } | |
892 | ||
299894cc JB |
893 | /* |
894 | * After the item has been detached from the filesystem view, we are | |
895 | * ready to tear it out of the hierarchy. Notify the client before | |
896 | * we do that so they can perform any cleanup that requires | |
897 | * navigating the hierarchy. A client does not need to provide this | |
898 | * callback. The subsystem semaphore MUST be held by the caller, and | |
899 | * references must be valid for both items. It also assumes the | |
900 | * caller has validated ci_type. | |
901 | */ | |
902 | static void client_disconnect_notify(struct config_item *parent_item, | |
903 | struct config_item *item) | |
904 | { | |
905 | struct config_item_type *type; | |
906 | ||
907 | type = parent_item->ci_type; | |
908 | BUG_ON(!type); | |
909 | ||
910 | if (type->ct_group_ops && type->ct_group_ops->disconnect_notify) | |
911 | type->ct_group_ops->disconnect_notify(to_config_group(parent_item), | |
912 | item); | |
913 | } | |
914 | ||
7063fbf2 JB |
915 | /* |
916 | * Drop the initial reference from make_item()/make_group() | |
917 | * This function assumes that reference is held on item | |
918 | * and that item holds a valid reference to the parent. Also, it | |
919 | * assumes the caller has validated ci_type. | |
920 | */ | |
921 | static void client_drop_item(struct config_item *parent_item, | |
922 | struct config_item *item) | |
923 | { | |
924 | struct config_item_type *type; | |
925 | ||
926 | type = parent_item->ci_type; | |
927 | BUG_ON(!type); | |
928 | ||
eed7a0db JB |
929 | /* |
930 | * If ->drop_item() exists, it is responsible for the | |
931 | * config_item_put(). | |
932 | */ | |
7063fbf2 JB |
933 | if (type->ct_group_ops && type->ct_group_ops->drop_item) |
934 | type->ct_group_ops->drop_item(to_config_group(parent_item), | |
299894cc | 935 | item); |
7063fbf2 JB |
936 | else |
937 | config_item_put(item); | |
938 | } | |
939 | ||
631d1feb JB |
940 | #ifdef DEBUG |
941 | static void configfs_dump_one(struct configfs_dirent *sd, int level) | |
942 | { | |
c6686931 | 943 | pr_info("%*s\"%s\":\n", level, " ", configfs_get_name(sd)); |
631d1feb | 944 | |
c6686931 | 945 | #define type_print(_type) if (sd->s_type & _type) pr_info("%*s %s\n", level, " ", #_type); |
631d1feb JB |
946 | type_print(CONFIGFS_ROOT); |
947 | type_print(CONFIGFS_DIR); | |
948 | type_print(CONFIGFS_ITEM_ATTR); | |
949 | type_print(CONFIGFS_ITEM_LINK); | |
950 | type_print(CONFIGFS_USET_DIR); | |
951 | type_print(CONFIGFS_USET_DEFAULT); | |
952 | type_print(CONFIGFS_USET_DROPPING); | |
953 | #undef type_print | |
954 | } | |
955 | ||
956 | static int configfs_dump(struct configfs_dirent *sd, int level) | |
957 | { | |
958 | struct configfs_dirent *child_sd; | |
959 | int ret = 0; | |
960 | ||
961 | configfs_dump_one(sd, level); | |
962 | ||
963 | if (!(sd->s_type & (CONFIGFS_DIR|CONFIGFS_ROOT))) | |
964 | return 0; | |
965 | ||
966 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) { | |
967 | ret = configfs_dump(child_sd, level + 2); | |
968 | if (ret) | |
969 | break; | |
970 | } | |
971 | ||
972 | return ret; | |
973 | } | |
974 | #endif | |
975 | ||
976 | ||
977 | /* | |
978 | * configfs_depend_item() and configfs_undepend_item() | |
979 | * | |
980 | * WARNING: Do not call these from a configfs callback! | |
981 | * | |
982 | * This describes these functions and their helpers. | |
983 | * | |
984 | * Allow another kernel system to depend on a config_item. If this | |
25985edc | 985 | * happens, the item cannot go away until the dependent can live without |
631d1feb JB |
986 | * it. The idea is to give client modules as simple an interface as |
987 | * possible. When a system asks them to depend on an item, they just | |
988 | * call configfs_depend_item(). If the item is live and the client | |
989 | * driver is in good shape, we'll happily do the work for them. | |
990 | * | |
991 | * Why is the locking complex? Because configfs uses the VFS to handle | |
992 | * all locking, but this function is called outside the normal | |
993 | * VFS->configfs path. So it must take VFS locks to prevent the | |
994 | * VFS->configfs stuff (configfs_mkdir(), configfs_rmdir(), etc). This is | |
995 | * why you can't call these functions underneath configfs callbacks. | |
996 | * | |
997 | * Note, btw, that this can be called at *any* time, even when a configfs | |
998 | * subsystem isn't registered, or when configfs is loading or unloading. | |
999 | * Just like configfs_register_subsystem(). So we take the same | |
420118ca LR |
1000 | * precautions. We pin the filesystem. We lock configfs_dirent_lock. |
1001 | * If we can find the target item in the | |
631d1feb | 1002 | * configfs tree, it must be part of the subsystem tree as well, so we |
420118ca LR |
1003 | * do not need the subsystem semaphore. Holding configfs_dirent_lock helps |
1004 | * locking out mkdir() and rmdir(), who might be racing us. | |
631d1feb JB |
1005 | */ |
1006 | ||
1007 | /* | |
1008 | * configfs_depend_prep() | |
1009 | * | |
1010 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are | |
1011 | * attributes. This is similar but not the same to configfs_detach_prep(). | |
1012 | * Note that configfs_detach_prep() expects the parent to be locked when it | |
1013 | * is called, but we lock the parent *inside* configfs_depend_prep(). We | |
1014 | * do that so we can unlock it if we find nothing. | |
1015 | * | |
1016 | * Here we do a depth-first search of the dentry hierarchy looking for | |
420118ca LR |
1017 | * our object. |
1018 | * We deliberately ignore items tagged as dropping since they are virtually | |
1019 | * dead, as well as items in the middle of attachment since they virtually | |
1020 | * do not exist yet. This completes the locking out of racing mkdir() and | |
1021 | * rmdir(). | |
1022 | * Note: subdirectories in the middle of attachment start with s_type = | |
1023 | * CONFIGFS_DIR|CONFIGFS_USET_CREATING set by create_dir(). When | |
1024 | * CONFIGFS_USET_CREATING is set, we ignore the item. The actual set of | |
1025 | * s_type is in configfs_new_dirent(), which has configfs_dirent_lock. | |
631d1feb | 1026 | * |
420118ca | 1027 | * If the target is not found, -ENOENT is bubbled up. |
631d1feb JB |
1028 | * |
1029 | * This adds a requirement that all config_items be unique! | |
1030 | * | |
420118ca | 1031 | * This is recursive. There isn't |
631d1feb JB |
1032 | * much on the stack, though, so folks that need this function - be careful |
1033 | * about your stack! Patches will be accepted to make it iterative. | |
1034 | */ | |
1035 | static int configfs_depend_prep(struct dentry *origin, | |
1036 | struct config_item *target) | |
1037 | { | |
49deb4bc | 1038 | struct configfs_dirent *child_sd, *sd; |
631d1feb JB |
1039 | int ret = 0; |
1040 | ||
49deb4bc WY |
1041 | BUG_ON(!origin || !origin->d_fsdata); |
1042 | sd = origin->d_fsdata; | |
631d1feb | 1043 | |
631d1feb JB |
1044 | if (sd->s_element == target) /* Boo-yah */ |
1045 | goto out; | |
1046 | ||
1047 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) { | |
420118ca LR |
1048 | if ((child_sd->s_type & CONFIGFS_DIR) && |
1049 | !(child_sd->s_type & CONFIGFS_USET_DROPPING) && | |
1050 | !(child_sd->s_type & CONFIGFS_USET_CREATING)) { | |
631d1feb JB |
1051 | ret = configfs_depend_prep(child_sd->s_dentry, |
1052 | target); | |
1053 | if (!ret) | |
1054 | goto out; /* Child path boo-yah */ | |
1055 | } | |
1056 | } | |
1057 | ||
1058 | /* We looped all our children and didn't find target */ | |
631d1feb JB |
1059 | ret = -ENOENT; |
1060 | ||
1061 | out: | |
1062 | return ret; | |
1063 | } | |
1064 | ||
631d1feb JB |
1065 | int configfs_depend_item(struct configfs_subsystem *subsys, |
1066 | struct config_item *target) | |
1067 | { | |
1068 | int ret; | |
1069 | struct configfs_dirent *p, *root_sd, *subsys_sd = NULL; | |
1070 | struct config_item *s_item = &subsys->su_group.cg_item; | |
b7c177fc | 1071 | struct dentry *root; |
631d1feb JB |
1072 | |
1073 | /* | |
1074 | * Pin the configfs filesystem. This means we can safely access | |
1075 | * the root of the configfs filesystem. | |
1076 | */ | |
2a152ad3 AV |
1077 | root = configfs_pin_fs(); |
1078 | if (IS_ERR(root)) | |
1079 | return PTR_ERR(root); | |
631d1feb JB |
1080 | |
1081 | /* | |
1082 | * Next, lock the root directory. We're going to check that the | |
1083 | * subsystem is really registered, and so we need to lock out | |
1084 | * configfs_[un]register_subsystem(). | |
1085 | */ | |
b7c177fc | 1086 | mutex_lock(&root->d_inode->i_mutex); |
631d1feb | 1087 | |
b7c177fc | 1088 | root_sd = root->d_fsdata; |
631d1feb JB |
1089 | |
1090 | list_for_each_entry(p, &root_sd->s_children, s_sibling) { | |
1091 | if (p->s_type & CONFIGFS_DIR) { | |
1092 | if (p->s_element == s_item) { | |
1093 | subsys_sd = p; | |
1094 | break; | |
1095 | } | |
1096 | } | |
1097 | } | |
1098 | ||
1099 | if (!subsys_sd) { | |
1100 | ret = -ENOENT; | |
1101 | goto out_unlock_fs; | |
1102 | } | |
1103 | ||
1104 | /* Ok, now we can trust subsys/s_item */ | |
1105 | ||
420118ca LR |
1106 | spin_lock(&configfs_dirent_lock); |
1107 | /* Scan the tree, return 0 if found */ | |
631d1feb JB |
1108 | ret = configfs_depend_prep(subsys_sd->s_dentry, target); |
1109 | if (ret) | |
420118ca | 1110 | goto out_unlock_dirent_lock; |
631d1feb | 1111 | |
420118ca LR |
1112 | /* |
1113 | * We are sure that the item is not about to be removed by rmdir(), and | |
1114 | * not in the middle of attachment by mkdir(). | |
1115 | */ | |
631d1feb JB |
1116 | p = target->ci_dentry->d_fsdata; |
1117 | p->s_dependent_count += 1; | |
1118 | ||
420118ca LR |
1119 | out_unlock_dirent_lock: |
1120 | spin_unlock(&configfs_dirent_lock); | |
631d1feb | 1121 | out_unlock_fs: |
b7c177fc | 1122 | mutex_unlock(&root->d_inode->i_mutex); |
631d1feb JB |
1123 | |
1124 | /* | |
1125 | * If we succeeded, the fs is pinned via other methods. If not, | |
1126 | * we're done with it anyway. So release_fs() is always right. | |
1127 | */ | |
1128 | configfs_release_fs(); | |
1129 | ||
1130 | return ret; | |
1131 | } | |
1132 | EXPORT_SYMBOL(configfs_depend_item); | |
1133 | ||
1134 | /* | |
1135 | * Release the dependent linkage. This is much simpler than | |
1136 | * configfs_depend_item() because we know that that the client driver is | |
1137 | * pinned, thus the subsystem is pinned, and therefore configfs is pinned. | |
1138 | */ | |
1139 | void configfs_undepend_item(struct configfs_subsystem *subsys, | |
1140 | struct config_item *target) | |
1141 | { | |
1142 | struct configfs_dirent *sd; | |
1143 | ||
1144 | /* | |
420118ca LR |
1145 | * Since we can trust everything is pinned, we just need |
1146 | * configfs_dirent_lock. | |
631d1feb | 1147 | */ |
420118ca | 1148 | spin_lock(&configfs_dirent_lock); |
631d1feb JB |
1149 | |
1150 | sd = target->ci_dentry->d_fsdata; | |
1151 | BUG_ON(sd->s_dependent_count < 1); | |
1152 | ||
1153 | sd->s_dependent_count -= 1; | |
1154 | ||
1155 | /* | |
1156 | * After this unlock, we cannot trust the item to stay alive! | |
1157 | * DO NOT REFERENCE item after this unlock. | |
1158 | */ | |
420118ca | 1159 | spin_unlock(&configfs_dirent_lock); |
631d1feb JB |
1160 | } |
1161 | EXPORT_SYMBOL(configfs_undepend_item); | |
7063fbf2 | 1162 | |
18bb1db3 | 1163 | static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) |
7063fbf2 | 1164 | { |
a6795e9e JB |
1165 | int ret = 0; |
1166 | int module_got = 0; | |
1167 | struct config_group *group = NULL; | |
1168 | struct config_item *item = NULL; | |
7063fbf2 JB |
1169 | struct config_item *parent_item; |
1170 | struct configfs_subsystem *subsys; | |
1171 | struct configfs_dirent *sd; | |
1172 | struct config_item_type *type; | |
70526b67 | 1173 | struct module *subsys_owner = NULL, *new_item_owner = NULL; |
7063fbf2 JB |
1174 | char *name; |
1175 | ||
7063fbf2 | 1176 | sd = dentry->d_parent->d_fsdata; |
2a109f2a LR |
1177 | |
1178 | /* | |
1179 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
1180 | * being attached | |
1181 | */ | |
1182 | if (!configfs_dirent_is_ready(sd)) { | |
1183 | ret = -ENOENT; | |
1184 | goto out; | |
1185 | } | |
1186 | ||
84efad1a JB |
1187 | if (!(sd->s_type & CONFIGFS_USET_DIR)) { |
1188 | ret = -EPERM; | |
1189 | goto out; | |
1190 | } | |
7063fbf2 | 1191 | |
84efad1a | 1192 | /* Get a working ref for the duration of this function */ |
7063fbf2 JB |
1193 | parent_item = configfs_get_config_item(dentry->d_parent); |
1194 | type = parent_item->ci_type; | |
1195 | subsys = to_config_group(parent_item)->cg_subsys; | |
1196 | BUG_ON(!subsys); | |
1197 | ||
1198 | if (!type || !type->ct_group_ops || | |
1199 | (!type->ct_group_ops->make_group && | |
1200 | !type->ct_group_ops->make_item)) { | |
84efad1a JB |
1201 | ret = -EPERM; /* Lack-of-mkdir returns -EPERM */ |
1202 | goto out_put; | |
7063fbf2 JB |
1203 | } |
1204 | ||
70526b67 JB |
1205 | /* |
1206 | * The subsystem may belong to a different module than the item | |
1207 | * being created. We don't want to safely pin the new item but | |
1208 | * fail to pin the subsystem it sits under. | |
1209 | */ | |
1210 | if (!subsys->su_group.cg_item.ci_type) { | |
1211 | ret = -EINVAL; | |
1212 | goto out_put; | |
1213 | } | |
1214 | subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; | |
1215 | if (!try_module_get(subsys_owner)) { | |
1216 | ret = -EINVAL; | |
1217 | goto out_put; | |
1218 | } | |
1219 | ||
7063fbf2 JB |
1220 | name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL); |
1221 | if (!name) { | |
84efad1a | 1222 | ret = -ENOMEM; |
70526b67 | 1223 | goto out_subsys_put; |
7063fbf2 | 1224 | } |
84efad1a | 1225 | |
7063fbf2 JB |
1226 | snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name); |
1227 | ||
e6bd07ae | 1228 | mutex_lock(&subsys->su_mutex); |
7063fbf2 | 1229 | if (type->ct_group_ops->make_group) { |
f89ab861 | 1230 | group = type->ct_group_ops->make_group(to_config_group(parent_item), name); |
a6795e9e JB |
1231 | if (!group) |
1232 | group = ERR_PTR(-ENOMEM); | |
1233 | if (!IS_ERR(group)) { | |
7063fbf2 JB |
1234 | link_group(to_config_group(parent_item), group); |
1235 | item = &group->cg_item; | |
a6795e9e JB |
1236 | } else |
1237 | ret = PTR_ERR(group); | |
7063fbf2 | 1238 | } else { |
f89ab861 | 1239 | item = type->ct_group_ops->make_item(to_config_group(parent_item), name); |
a6795e9e JB |
1240 | if (!item) |
1241 | item = ERR_PTR(-ENOMEM); | |
1242 | if (!IS_ERR(item)) | |
7063fbf2 | 1243 | link_obj(parent_item, item); |
a6795e9e JB |
1244 | else |
1245 | ret = PTR_ERR(item); | |
7063fbf2 | 1246 | } |
e6bd07ae | 1247 | mutex_unlock(&subsys->su_mutex); |
7063fbf2 JB |
1248 | |
1249 | kfree(name); | |
a6795e9e | 1250 | if (ret) { |
eed7a0db | 1251 | /* |
dacdd0e0 | 1252 | * If ret != 0, then link_obj() was never called. |
eed7a0db JB |
1253 | * There are no extra references to clean up. |
1254 | */ | |
70526b67 | 1255 | goto out_subsys_put; |
7063fbf2 JB |
1256 | } |
1257 | ||
eed7a0db JB |
1258 | /* |
1259 | * link_obj() has been called (via link_group() for groups). | |
1260 | * From here on out, errors must clean that up. | |
1261 | */ | |
1262 | ||
7063fbf2 | 1263 | type = item->ci_type; |
eed7a0db JB |
1264 | if (!type) { |
1265 | ret = -EINVAL; | |
1266 | goto out_unlink; | |
1267 | } | |
7063fbf2 | 1268 | |
70526b67 JB |
1269 | new_item_owner = type->ct_owner; |
1270 | if (!try_module_get(new_item_owner)) { | |
eed7a0db JB |
1271 | ret = -EINVAL; |
1272 | goto out_unlink; | |
1273 | } | |
7063fbf2 | 1274 | |
eed7a0db JB |
1275 | /* |
1276 | * I hate doing it this way, but if there is | |
1277 | * an error, module_put() probably should | |
1278 | * happen after any cleanup. | |
1279 | */ | |
1280 | module_got = 1; | |
1281 | ||
6d8344ba LR |
1282 | /* |
1283 | * Make racing rmdir() fail if it did not tag parent with | |
1284 | * CONFIGFS_USET_DROPPING | |
1285 | * Note: if CONFIGFS_USET_DROPPING is already set, attach_group() will | |
1286 | * fail and let rmdir() terminate correctly | |
1287 | */ | |
1288 | spin_lock(&configfs_dirent_lock); | |
1289 | /* This will make configfs_detach_prep() fail */ | |
1290 | sd->s_type |= CONFIGFS_USET_IN_MKDIR; | |
1291 | spin_unlock(&configfs_dirent_lock); | |
1292 | ||
eed7a0db JB |
1293 | if (group) |
1294 | ret = configfs_attach_group(parent_item, item, dentry); | |
1295 | else | |
1296 | ret = configfs_attach_item(parent_item, item, dentry); | |
1297 | ||
6d8344ba LR |
1298 | spin_lock(&configfs_dirent_lock); |
1299 | sd->s_type &= ~CONFIGFS_USET_IN_MKDIR; | |
2a109f2a LR |
1300 | if (!ret) |
1301 | configfs_dir_set_ready(dentry->d_fsdata); | |
6d8344ba LR |
1302 | spin_unlock(&configfs_dirent_lock); |
1303 | ||
eed7a0db JB |
1304 | out_unlink: |
1305 | if (ret) { | |
1306 | /* Tear down everything we built up */ | |
e6bd07ae | 1307 | mutex_lock(&subsys->su_mutex); |
299894cc JB |
1308 | |
1309 | client_disconnect_notify(parent_item, item); | |
eed7a0db JB |
1310 | if (group) |
1311 | unlink_group(group); | |
1312 | else | |
1313 | unlink_obj(item); | |
1314 | client_drop_item(parent_item, item); | |
299894cc | 1315 | |
e6bd07ae | 1316 | mutex_unlock(&subsys->su_mutex); |
eed7a0db JB |
1317 | |
1318 | if (module_got) | |
70526b67 | 1319 | module_put(new_item_owner); |
7063fbf2 JB |
1320 | } |
1321 | ||
70526b67 JB |
1322 | out_subsys_put: |
1323 | if (ret) | |
1324 | module_put(subsys_owner); | |
1325 | ||
84efad1a JB |
1326 | out_put: |
1327 | /* | |
eed7a0db JB |
1328 | * link_obj()/link_group() took a reference from child->parent, |
1329 | * so the parent is safely pinned. We can drop our working | |
1330 | * reference. | |
84efad1a JB |
1331 | */ |
1332 | config_item_put(parent_item); | |
1333 | ||
1334 | out: | |
7063fbf2 JB |
1335 | return ret; |
1336 | } | |
1337 | ||
1338 | static int configfs_rmdir(struct inode *dir, struct dentry *dentry) | |
1339 | { | |
1340 | struct config_item *parent_item; | |
1341 | struct config_item *item; | |
1342 | struct configfs_subsystem *subsys; | |
1343 | struct configfs_dirent *sd; | |
70526b67 | 1344 | struct module *subsys_owner = NULL, *dead_item_owner = NULL; |
7063fbf2 JB |
1345 | int ret; |
1346 | ||
7063fbf2 JB |
1347 | sd = dentry->d_fsdata; |
1348 | if (sd->s_type & CONFIGFS_USET_DEFAULT) | |
1349 | return -EPERM; | |
1350 | ||
84efad1a | 1351 | /* Get a working ref until we have the child */ |
7063fbf2 JB |
1352 | parent_item = configfs_get_config_item(dentry->d_parent); |
1353 | subsys = to_config_group(parent_item)->cg_subsys; | |
1354 | BUG_ON(!subsys); | |
1355 | ||
1356 | if (!parent_item->ci_type) { | |
1357 | config_item_put(parent_item); | |
1358 | return -EINVAL; | |
1359 | } | |
1360 | ||
70526b67 JB |
1361 | /* configfs_mkdir() shouldn't have allowed this */ |
1362 | BUG_ON(!subsys->su_group.cg_item.ci_type); | |
1363 | subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; | |
1364 | ||
9a73d78c LR |
1365 | /* |
1366 | * Ensure that no racing symlink() will make detach_prep() fail while | |
1367 | * the new link is temporarily attached | |
1368 | */ | |
6d8344ba LR |
1369 | do { |
1370 | struct mutex *wait_mutex; | |
1371 | ||
de6bf18e LR |
1372 | mutex_lock(&configfs_symlink_mutex); |
1373 | spin_lock(&configfs_dirent_lock); | |
420118ca LR |
1374 | /* |
1375 | * Here's where we check for dependents. We're protected by | |
1376 | * configfs_dirent_lock. | |
1377 | * If no dependent, atomically tag the item as dropping. | |
1378 | */ | |
1379 | ret = sd->s_dependent_count ? -EBUSY : 0; | |
1380 | if (!ret) { | |
1381 | ret = configfs_detach_prep(dentry, &wait_mutex); | |
1382 | if (ret) | |
1383 | configfs_detach_rollback(dentry); | |
1384 | } | |
de6bf18e LR |
1385 | spin_unlock(&configfs_dirent_lock); |
1386 | mutex_unlock(&configfs_symlink_mutex); | |
1387 | ||
1388 | if (ret) { | |
6d8344ba LR |
1389 | if (ret != -EAGAIN) { |
1390 | config_item_put(parent_item); | |
1391 | return ret; | |
1392 | } | |
1393 | ||
1394 | /* Wait until the racing operation terminates */ | |
1395 | mutex_lock(wait_mutex); | |
1396 | mutex_unlock(wait_mutex); | |
6d8344ba LR |
1397 | } |
1398 | } while (ret == -EAGAIN); | |
7063fbf2 | 1399 | |
84efad1a | 1400 | /* Get a working ref for the duration of this function */ |
7063fbf2 JB |
1401 | item = configfs_get_config_item(dentry); |
1402 | ||
1403 | /* Drop reference from above, item already holds one. */ | |
1404 | config_item_put(parent_item); | |
1405 | ||
1406 | if (item->ci_type) | |
70526b67 | 1407 | dead_item_owner = item->ci_type->ct_owner; |
7063fbf2 JB |
1408 | |
1409 | if (sd->s_type & CONFIGFS_USET_DIR) { | |
1410 | configfs_detach_group(item); | |
1411 | ||
e6bd07ae | 1412 | mutex_lock(&subsys->su_mutex); |
299894cc | 1413 | client_disconnect_notify(parent_item, item); |
7063fbf2 JB |
1414 | unlink_group(to_config_group(item)); |
1415 | } else { | |
1416 | configfs_detach_item(item); | |
1417 | ||
e6bd07ae | 1418 | mutex_lock(&subsys->su_mutex); |
299894cc | 1419 | client_disconnect_notify(parent_item, item); |
7063fbf2 JB |
1420 | unlink_obj(item); |
1421 | } | |
1422 | ||
1423 | client_drop_item(parent_item, item); | |
e6bd07ae | 1424 | mutex_unlock(&subsys->su_mutex); |
7063fbf2 JB |
1425 | |
1426 | /* Drop our reference from above */ | |
1427 | config_item_put(item); | |
1428 | ||
70526b67 JB |
1429 | module_put(dead_item_owner); |
1430 | module_put(subsys_owner); | |
7063fbf2 JB |
1431 | |
1432 | return 0; | |
1433 | } | |
1434 | ||
754661f1 | 1435 | const struct inode_operations configfs_dir_inode_operations = { |
7063fbf2 JB |
1436 | .mkdir = configfs_mkdir, |
1437 | .rmdir = configfs_rmdir, | |
1438 | .symlink = configfs_symlink, | |
1439 | .unlink = configfs_unlink, | |
1440 | .lookup = configfs_lookup, | |
3d0f89bb | 1441 | .setattr = configfs_setattr, |
7063fbf2 JB |
1442 | }; |
1443 | ||
81d44ed1 AV |
1444 | const struct inode_operations configfs_root_inode_operations = { |
1445 | .lookup = configfs_lookup, | |
1446 | .setattr = configfs_setattr, | |
1447 | }; | |
1448 | ||
7063fbf2 JB |
1449 | #if 0 |
1450 | int configfs_rename_dir(struct config_item * item, const char *new_name) | |
1451 | { | |
1452 | int error = 0; | |
1453 | struct dentry * new_dentry, * parent; | |
1454 | ||
1455 | if (!strcmp(config_item_name(item), new_name)) | |
1456 | return -EINVAL; | |
1457 | ||
1458 | if (!item->parent) | |
1459 | return -EINVAL; | |
1460 | ||
1461 | down_write(&configfs_rename_sem); | |
1462 | parent = item->parent->dentry; | |
1463 | ||
1b1dcc1b | 1464 | mutex_lock(&parent->d_inode->i_mutex); |
7063fbf2 JB |
1465 | |
1466 | new_dentry = lookup_one_len(new_name, parent, strlen(new_name)); | |
1467 | if (!IS_ERR(new_dentry)) { | |
e7515d06 | 1468 | if (!new_dentry->d_inode) { |
7063fbf2 JB |
1469 | error = config_item_set_name(item, "%s", new_name); |
1470 | if (!error) { | |
1471 | d_add(new_dentry, NULL); | |
1472 | d_move(item->dentry, new_dentry); | |
1473 | } | |
1474 | else | |
1475 | d_delete(new_dentry); | |
1476 | } else | |
1477 | error = -EEXIST; | |
1478 | dput(new_dentry); | |
1479 | } | |
1b1dcc1b | 1480 | mutex_unlock(&parent->d_inode->i_mutex); |
7063fbf2 JB |
1481 | up_write(&configfs_rename_sem); |
1482 | ||
1483 | return error; | |
1484 | } | |
1485 | #endif | |
1486 | ||
1487 | static int configfs_dir_open(struct inode *inode, struct file *file) | |
1488 | { | |
867fa491 | 1489 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 | 1490 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
2a109f2a | 1491 | int err; |
7063fbf2 | 1492 | |
1b1dcc1b | 1493 | mutex_lock(&dentry->d_inode->i_mutex); |
2a109f2a LR |
1494 | /* |
1495 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
1496 | * being attached | |
1497 | */ | |
1498 | err = -ENOENT; | |
1499 | if (configfs_dirent_is_ready(parent_sd)) { | |
420118ca | 1500 | file->private_data = configfs_new_dirent(parent_sd, NULL, 0); |
2a109f2a LR |
1501 | if (IS_ERR(file->private_data)) |
1502 | err = PTR_ERR(file->private_data); | |
1503 | else | |
1504 | err = 0; | |
1505 | } | |
1b1dcc1b | 1506 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 | 1507 | |
2a109f2a | 1508 | return err; |
7063fbf2 JB |
1509 | } |
1510 | ||
1511 | static int configfs_dir_close(struct inode *inode, struct file *file) | |
1512 | { | |
867fa491 | 1513 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 JB |
1514 | struct configfs_dirent * cursor = file->private_data; |
1515 | ||
1b1dcc1b | 1516 | mutex_lock(&dentry->d_inode->i_mutex); |
6f610764 | 1517 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 1518 | list_del_init(&cursor->s_sibling); |
6f610764 | 1519 | spin_unlock(&configfs_dirent_lock); |
1b1dcc1b | 1520 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1521 | |
1522 | release_configfs_dirent(cursor); | |
1523 | ||
1524 | return 0; | |
1525 | } | |
1526 | ||
1527 | /* Relationship between s_mode and the DT_xxx types */ | |
1528 | static inline unsigned char dt_type(struct configfs_dirent *sd) | |
1529 | { | |
1530 | return (sd->s_mode >> 12) & 15; | |
1531 | } | |
1532 | ||
52018855 | 1533 | static int configfs_readdir(struct file *file, struct dir_context *ctx) |
7063fbf2 | 1534 | { |
52018855 | 1535 | struct dentry *dentry = file->f_path.dentry; |
b7c177fc | 1536 | struct super_block *sb = dentry->d_sb; |
7063fbf2 | 1537 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
52018855 | 1538 | struct configfs_dirent *cursor = file->private_data; |
7063fbf2 | 1539 | struct list_head *p, *q = &cursor->s_sibling; |
24307aa1 | 1540 | ino_t ino = 0; |
7063fbf2 | 1541 | |
52018855 AV |
1542 | if (!dir_emit_dots(file, ctx)) |
1543 | return 0; | |
1544 | if (ctx->pos == 2) { | |
1545 | spin_lock(&configfs_dirent_lock); | |
1546 | list_move(q, &parent_sd->s_children); | |
1547 | spin_unlock(&configfs_dirent_lock); | |
1548 | } | |
1549 | for (p = q->next; p != &parent_sd->s_children; p = p->next) { | |
1550 | struct configfs_dirent *next; | |
1551 | const char *name; | |
1552 | int len; | |
1553 | struct inode *inode = NULL; | |
1554 | ||
1555 | next = list_entry(p, struct configfs_dirent, s_sibling); | |
1556 | if (!next->s_element) | |
1557 | continue; | |
7063fbf2 | 1558 | |
52018855 AV |
1559 | name = configfs_get_name(next); |
1560 | len = strlen(name); | |
1561 | ||
1562 | /* | |
1563 | * We'll have a dentry and an inode for | |
1564 | * PINNED items and for open attribute | |
1565 | * files. We lock here to prevent a race | |
1566 | * with configfs_d_iput() clearing | |
1567 | * s_dentry before calling iput(). | |
1568 | * | |
1569 | * Why do we go to the trouble? If | |
1570 | * someone has an attribute file open, | |
1571 | * the inode number should match until | |
1572 | * they close it. Beyond that, we don't | |
1573 | * care. | |
1574 | */ | |
1575 | spin_lock(&configfs_dirent_lock); | |
1576 | dentry = next->s_dentry; | |
1577 | if (dentry) | |
1578 | inode = dentry->d_inode; | |
1579 | if (inode) | |
1580 | ino = inode->i_ino; | |
1581 | spin_unlock(&configfs_dirent_lock); | |
1582 | if (!inode) | |
1583 | ino = iunique(sb, 2); | |
7063fbf2 | 1584 | |
52018855 AV |
1585 | if (!dir_emit(ctx, name, len, ino, dt_type(next))) |
1586 | return 0; | |
7063fbf2 | 1587 | |
52018855 AV |
1588 | spin_lock(&configfs_dirent_lock); |
1589 | list_move(q, p); | |
1590 | spin_unlock(&configfs_dirent_lock); | |
1591 | p = q; | |
1592 | ctx->pos++; | |
7063fbf2 JB |
1593 | } |
1594 | return 0; | |
1595 | } | |
1596 | ||
965c8e59 | 1597 | static loff_t configfs_dir_lseek(struct file *file, loff_t offset, int whence) |
7063fbf2 | 1598 | { |
867fa491 | 1599 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 | 1600 | |
1b1dcc1b | 1601 | mutex_lock(&dentry->d_inode->i_mutex); |
965c8e59 | 1602 | switch (whence) { |
7063fbf2 JB |
1603 | case 1: |
1604 | offset += file->f_pos; | |
1605 | case 0: | |
1606 | if (offset >= 0) | |
1607 | break; | |
1608 | default: | |
496ad9aa | 1609 | mutex_unlock(&file_inode(file)->i_mutex); |
7063fbf2 JB |
1610 | return -EINVAL; |
1611 | } | |
1612 | if (offset != file->f_pos) { | |
1613 | file->f_pos = offset; | |
1614 | if (file->f_pos >= 2) { | |
1615 | struct configfs_dirent *sd = dentry->d_fsdata; | |
1616 | struct configfs_dirent *cursor = file->private_data; | |
1617 | struct list_head *p; | |
1618 | loff_t n = file->f_pos - 2; | |
1619 | ||
6f610764 | 1620 | spin_lock(&configfs_dirent_lock); |
7063fbf2 JB |
1621 | list_del(&cursor->s_sibling); |
1622 | p = sd->s_children.next; | |
1623 | while (n && p != &sd->s_children) { | |
1624 | struct configfs_dirent *next; | |
1625 | next = list_entry(p, struct configfs_dirent, | |
1626 | s_sibling); | |
1627 | if (next->s_element) | |
1628 | n--; | |
1629 | p = p->next; | |
1630 | } | |
1631 | list_add_tail(&cursor->s_sibling, p); | |
6f610764 | 1632 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
1633 | } |
1634 | } | |
1b1dcc1b | 1635 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1636 | return offset; |
1637 | } | |
1638 | ||
4b6f5d20 | 1639 | const struct file_operations configfs_dir_operations = { |
7063fbf2 JB |
1640 | .open = configfs_dir_open, |
1641 | .release = configfs_dir_close, | |
1642 | .llseek = configfs_dir_lseek, | |
1643 | .read = generic_read_dir, | |
52018855 | 1644 | .iterate = configfs_readdir, |
7063fbf2 JB |
1645 | }; |
1646 | ||
1647 | int configfs_register_subsystem(struct configfs_subsystem *subsys) | |
1648 | { | |
1649 | int err; | |
1650 | struct config_group *group = &subsys->su_group; | |
7063fbf2 | 1651 | struct dentry *dentry; |
b7c177fc | 1652 | struct dentry *root; |
7063fbf2 JB |
1653 | struct configfs_dirent *sd; |
1654 | ||
2a152ad3 AV |
1655 | root = configfs_pin_fs(); |
1656 | if (IS_ERR(root)) | |
1657 | return PTR_ERR(root); | |
7063fbf2 JB |
1658 | |
1659 | if (!group->cg_item.ci_name) | |
1660 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
1661 | ||
b7c177fc | 1662 | sd = root->d_fsdata; |
7063fbf2 JB |
1663 | link_group(to_config_group(sd->s_element), group); |
1664 | ||
b7c177fc | 1665 | mutex_lock_nested(&root->d_inode->i_mutex, I_MUTEX_PARENT); |
7063fbf2 | 1666 | |
7063fbf2 | 1667 | err = -ENOMEM; |
ec193cf5 | 1668 | dentry = d_alloc_name(root, group->cg_item.ci_name); |
afdf04ea JB |
1669 | if (dentry) { |
1670 | d_add(dentry, NULL); | |
7063fbf2 | 1671 | |
afdf04ea JB |
1672 | err = configfs_attach_group(sd->s_element, &group->cg_item, |
1673 | dentry); | |
1674 | if (err) { | |
df7f9967 JB |
1675 | BUG_ON(dentry->d_inode); |
1676 | d_drop(dentry); | |
afdf04ea | 1677 | dput(dentry); |
2a109f2a LR |
1678 | } else { |
1679 | spin_lock(&configfs_dirent_lock); | |
1680 | configfs_dir_set_ready(dentry->d_fsdata); | |
1681 | spin_unlock(&configfs_dirent_lock); | |
afdf04ea JB |
1682 | } |
1683 | } | |
7063fbf2 | 1684 | |
b7c177fc | 1685 | mutex_unlock(&root->d_inode->i_mutex); |
7063fbf2 | 1686 | |
afdf04ea JB |
1687 | if (err) { |
1688 | unlink_group(group); | |
1689 | configfs_release_fs(); | |
7063fbf2 JB |
1690 | } |
1691 | ||
1692 | return err; | |
1693 | } | |
1694 | ||
1695 | void configfs_unregister_subsystem(struct configfs_subsystem *subsys) | |
1696 | { | |
1697 | struct config_group *group = &subsys->su_group; | |
1698 | struct dentry *dentry = group->cg_item.ci_dentry; | |
b7c177fc | 1699 | struct dentry *root = dentry->d_sb->s_root; |
7063fbf2 | 1700 | |
b7c177fc | 1701 | if (dentry->d_parent != root) { |
1d88aa44 | 1702 | pr_err("Tried to unregister non-subsystem!\n"); |
7063fbf2 JB |
1703 | return; |
1704 | } | |
1705 | ||
b7c177fc | 1706 | mutex_lock_nested(&root->d_inode->i_mutex, |
55ed1602 MF |
1707 | I_MUTEX_PARENT); |
1708 | mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); | |
9a73d78c | 1709 | mutex_lock(&configfs_symlink_mutex); |
b3e76af8 | 1710 | spin_lock(&configfs_dirent_lock); |
6d8344ba | 1711 | if (configfs_detach_prep(dentry, NULL)) { |
1d88aa44 | 1712 | pr_err("Tried to unregister non-empty subsystem!\n"); |
7063fbf2 | 1713 | } |
b3e76af8 | 1714 | spin_unlock(&configfs_dirent_lock); |
9a73d78c | 1715 | mutex_unlock(&configfs_symlink_mutex); |
7063fbf2 JB |
1716 | configfs_detach_group(&group->cg_item); |
1717 | dentry->d_inode->i_flags |= S_DEAD; | |
d83c49f3 | 1718 | dont_mount(dentry); |
1b1dcc1b | 1719 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1720 | |
1721 | d_delete(dentry); | |
1722 | ||
b7c177fc | 1723 | mutex_unlock(&root->d_inode->i_mutex); |
7063fbf2 JB |
1724 | |
1725 | dput(dentry); | |
1726 | ||
1727 | unlink_group(group); | |
1728 | configfs_release_fs(); | |
1729 | } | |
1730 | ||
1731 | EXPORT_SYMBOL(configfs_register_subsystem); | |
1732 | EXPORT_SYMBOL(configfs_unregister_subsystem); |