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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) { | |
59 | BUG_ON(sd->s_dentry != dentry); | |
24307aa1 JB |
60 | /* Coordinate with configfs_readdir */ |
61 | spin_lock(&configfs_dirent_lock); | |
7063fbf2 | 62 | sd->s_dentry = NULL; |
24307aa1 | 63 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
64 | configfs_put(sd); |
65 | } | |
66 | iput(inode); | |
67 | } | |
68 | ||
69 | /* | |
70 | * We _must_ delete our dentries on last dput, as the chain-to-parent | |
71 | * behavior is required to clear the parents of default_groups. | |
72 | */ | |
fe15ce44 | 73 | static int configfs_d_delete(const struct dentry *dentry) |
7063fbf2 JB |
74 | { |
75 | return 1; | |
76 | } | |
77 | ||
d463a0c4 | 78 | const struct dentry_operations configfs_dentry_ops = { |
7063fbf2 JB |
79 | .d_iput = configfs_d_iput, |
80 | /* simple_delete_dentry() isn't exported */ | |
81 | .d_delete = configfs_d_delete, | |
82 | }; | |
83 | ||
e74cc06d LR |
84 | #ifdef CONFIG_LOCKDEP |
85 | ||
86 | /* | |
87 | * Helpers to make lockdep happy with our recursive locking of default groups' | |
88 | * inodes (see configfs_attach_group() and configfs_detach_group()). | |
89 | * We put default groups i_mutexes in separate classes according to their depth | |
90 | * from the youngest non-default group ancestor. | |
91 | * | |
92 | * For a non-default group A having default groups A/B, A/C, and A/C/D, default | |
93 | * groups A/B and A/C will have their inode's mutex in class | |
94 | * default_group_class[0], and default group A/C/D will be in | |
95 | * default_group_class[1]. | |
96 | * | |
97 | * The lock classes are declared and assigned in inode.c, according to the | |
98 | * s_depth value. | |
99 | * The s_depth value is initialized to -1, adjusted to >= 0 when attaching | |
100 | * default groups, and reset to -1 when all default groups are attached. During | |
101 | * attachment, if configfs_create() sees s_depth > 0, the lock class of the new | |
102 | * inode's mutex is set to default_group_class[s_depth - 1]. | |
103 | */ | |
104 | ||
105 | static void configfs_init_dirent_depth(struct configfs_dirent *sd) | |
106 | { | |
107 | sd->s_depth = -1; | |
108 | } | |
109 | ||
110 | static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd, | |
111 | struct configfs_dirent *sd) | |
112 | { | |
113 | int parent_depth = parent_sd->s_depth; | |
114 | ||
115 | if (parent_depth >= 0) | |
116 | sd->s_depth = parent_depth + 1; | |
117 | } | |
118 | ||
119 | static void | |
120 | configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd) | |
121 | { | |
122 | /* | |
123 | * item's i_mutex class is already setup, so s_depth is now only | |
124 | * used to set new sub-directories s_depth, which is always done | |
125 | * with item's i_mutex locked. | |
126 | */ | |
127 | /* | |
128 | * sd->s_depth == -1 iff we are a non default group. | |
129 | * else (we are a default group) sd->s_depth > 0 (see | |
130 | * create_dir()). | |
131 | */ | |
132 | if (sd->s_depth == -1) | |
133 | /* | |
134 | * We are a non default group and we are going to create | |
135 | * default groups. | |
136 | */ | |
137 | sd->s_depth = 0; | |
138 | } | |
139 | ||
140 | static void | |
141 | configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd) | |
142 | { | |
143 | /* We will not create default groups anymore. */ | |
144 | sd->s_depth = -1; | |
145 | } | |
146 | ||
147 | #else /* CONFIG_LOCKDEP */ | |
148 | ||
149 | static void configfs_init_dirent_depth(struct configfs_dirent *sd) | |
150 | { | |
151 | } | |
152 | ||
153 | static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd, | |
154 | struct configfs_dirent *sd) | |
155 | { | |
156 | } | |
157 | ||
158 | static void | |
159 | configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd) | |
160 | { | |
161 | } | |
162 | ||
163 | static void | |
164 | configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd) | |
165 | { | |
166 | } | |
167 | ||
168 | #endif /* CONFIG_LOCKDEP */ | |
169 | ||
7063fbf2 JB |
170 | /* |
171 | * Allocates a new configfs_dirent and links it to the parent configfs_dirent | |
172 | */ | |
420118ca LR |
173 | static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *parent_sd, |
174 | void *element, int type) | |
7063fbf2 JB |
175 | { |
176 | struct configfs_dirent * sd; | |
177 | ||
c3762229 | 178 | sd = kmem_cache_zalloc(configfs_dir_cachep, GFP_KERNEL); |
7063fbf2 | 179 | if (!sd) |
107ed40b | 180 | return ERR_PTR(-ENOMEM); |
7063fbf2 | 181 | |
7063fbf2 JB |
182 | atomic_set(&sd->s_count, 1); |
183 | INIT_LIST_HEAD(&sd->s_links); | |
184 | INIT_LIST_HEAD(&sd->s_children); | |
7063fbf2 | 185 | sd->s_element = element; |
420118ca | 186 | sd->s_type = type; |
e74cc06d | 187 | configfs_init_dirent_depth(sd); |
6f610764 | 188 | spin_lock(&configfs_dirent_lock); |
b3e76af8 LR |
189 | if (parent_sd->s_type & CONFIGFS_USET_DROPPING) { |
190 | spin_unlock(&configfs_dirent_lock); | |
191 | kmem_cache_free(configfs_dir_cachep, sd); | |
192 | return ERR_PTR(-ENOENT); | |
193 | } | |
6f610764 LR |
194 | list_add(&sd->s_sibling, &parent_sd->s_children); |
195 | spin_unlock(&configfs_dirent_lock); | |
7063fbf2 JB |
196 | |
197 | return sd; | |
198 | } | |
199 | ||
b4c98f62 JB |
200 | /* |
201 | * | |
202 | * Return -EEXIST if there is already a configfs element with the same | |
203 | * name for the same parent. | |
204 | * | |
205 | * called with parent inode's i_mutex held | |
206 | */ | |
58d206c2 AB |
207 | static int configfs_dirent_exists(struct configfs_dirent *parent_sd, |
208 | const unsigned char *new) | |
b4c98f62 JB |
209 | { |
210 | struct configfs_dirent * sd; | |
211 | ||
212 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
213 | if (sd->s_element) { | |
214 | const unsigned char *existing = configfs_get_name(sd); | |
215 | if (strcmp(existing, new)) | |
216 | continue; | |
217 | else | |
218 | return -EEXIST; | |
219 | } | |
220 | } | |
221 | ||
222 | return 0; | |
223 | } | |
224 | ||
225 | ||
7063fbf2 JB |
226 | int configfs_make_dirent(struct configfs_dirent * parent_sd, |
227 | struct dentry * dentry, void * element, | |
228 | umode_t mode, int type) | |
229 | { | |
230 | struct configfs_dirent * sd; | |
231 | ||
420118ca | 232 | sd = configfs_new_dirent(parent_sd, element, type); |
107ed40b LR |
233 | if (IS_ERR(sd)) |
234 | return PTR_ERR(sd); | |
7063fbf2 JB |
235 | |
236 | sd->s_mode = mode; | |
7063fbf2 | 237 | sd->s_dentry = dentry; |
fbc8d4c0 | 238 | if (dentry) |
7063fbf2 | 239 | dentry->d_fsdata = configfs_get(sd); |
7063fbf2 JB |
240 | |
241 | return 0; | |
242 | } | |
243 | ||
244 | static int init_dir(struct inode * inode) | |
245 | { | |
246 | inode->i_op = &configfs_dir_inode_operations; | |
247 | inode->i_fop = &configfs_dir_operations; | |
248 | ||
249 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |
d8c76e6f | 250 | inc_nlink(inode); |
7063fbf2 JB |
251 | return 0; |
252 | } | |
253 | ||
ce8d2cdf | 254 | static int configfs_init_file(struct inode * inode) |
7063fbf2 JB |
255 | { |
256 | inode->i_size = PAGE_SIZE; | |
257 | inode->i_fop = &configfs_file_operations; | |
258 | return 0; | |
259 | } | |
260 | ||
261 | static int init_symlink(struct inode * inode) | |
262 | { | |
263 | inode->i_op = &configfs_symlink_inode_operations; | |
264 | return 0; | |
265 | } | |
266 | ||
0dd6c08a | 267 | static int create_dir(struct config_item *k, struct dentry *d) |
7063fbf2 JB |
268 | { |
269 | int error; | |
270 | umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; | |
0dd6c08a AV |
271 | struct dentry *p = d->d_parent; |
272 | ||
273 | BUG_ON(!k); | |
7063fbf2 | 274 | |
b4c98f62 JB |
275 | error = configfs_dirent_exists(p->d_fsdata, d->d_name.name); |
276 | if (!error) | |
277 | error = configfs_make_dirent(p->d_fsdata, d, k, mode, | |
2a109f2a | 278 | CONFIGFS_DIR | CONFIGFS_USET_CREATING); |
7063fbf2 | 279 | if (!error) { |
e74cc06d | 280 | configfs_set_dir_dirent_depth(p->d_fsdata, d->d_fsdata); |
3d0f89bb | 281 | error = configfs_create(d, mode, init_dir); |
7063fbf2 | 282 | if (!error) { |
d8c76e6f | 283 | inc_nlink(p->d_inode); |
3d0f89bb JB |
284 | } else { |
285 | struct configfs_dirent *sd = d->d_fsdata; | |
286 | if (sd) { | |
6f610764 | 287 | spin_lock(&configfs_dirent_lock); |
3d0f89bb | 288 | list_del_init(&sd->s_sibling); |
6f610764 | 289 | spin_unlock(&configfs_dirent_lock); |
3d0f89bb JB |
290 | configfs_put(sd); |
291 | } | |
7063fbf2 JB |
292 | } |
293 | } | |
294 | return error; | |
295 | } | |
296 | ||
297 | ||
298 | /** | |
299 | * configfs_create_dir - create a directory for an config_item. | |
300 | * @item: config_itemwe're creating directory for. | |
301 | * @dentry: config_item's dentry. | |
2a109f2a LR |
302 | * |
303 | * Note: user-created entries won't be allowed under this new directory | |
304 | * until it is validated by configfs_dir_set_ready() | |
7063fbf2 JB |
305 | */ |
306 | ||
307 | static int configfs_create_dir(struct config_item * item, struct dentry *dentry) | |
308 | { | |
0dd6c08a | 309 | int error = create_dir(item, dentry); |
7063fbf2 JB |
310 | if (!error) |
311 | item->ci_dentry = dentry; | |
312 | return error; | |
313 | } | |
314 | ||
2a109f2a LR |
315 | /* |
316 | * Allow userspace to create new entries under a new directory created with | |
317 | * configfs_create_dir(), and under all of its chidlren directories recursively. | |
318 | * @sd configfs_dirent of the new directory to validate | |
319 | * | |
320 | * Caller must hold configfs_dirent_lock. | |
321 | */ | |
322 | static void configfs_dir_set_ready(struct configfs_dirent *sd) | |
323 | { | |
324 | struct configfs_dirent *child_sd; | |
325 | ||
326 | sd->s_type &= ~CONFIGFS_USET_CREATING; | |
327 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) | |
328 | if (child_sd->s_type & CONFIGFS_USET_CREATING) | |
329 | configfs_dir_set_ready(child_sd); | |
330 | } | |
331 | ||
332 | /* | |
333 | * Check that a directory does not belong to a directory hierarchy being | |
334 | * attached and not validated yet. | |
335 | * @sd configfs_dirent of the directory to check | |
336 | * | |
337 | * @return non-zero iff the directory was validated | |
338 | * | |
339 | * Note: takes configfs_dirent_lock, so the result may change from false to true | |
340 | * in two consecutive calls, but never from true to false. | |
341 | */ | |
342 | int configfs_dirent_is_ready(struct configfs_dirent *sd) | |
343 | { | |
344 | int ret; | |
345 | ||
346 | spin_lock(&configfs_dirent_lock); | |
347 | ret = !(sd->s_type & CONFIGFS_USET_CREATING); | |
348 | spin_unlock(&configfs_dirent_lock); | |
349 | ||
350 | return ret; | |
351 | } | |
352 | ||
7063fbf2 JB |
353 | int configfs_create_link(struct configfs_symlink *sl, |
354 | struct dentry *parent, | |
355 | struct dentry *dentry) | |
356 | { | |
357 | int err = 0; | |
358 | umode_t mode = S_IFLNK | S_IRWXUGO; | |
359 | ||
3d0f89bb JB |
360 | err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode, |
361 | CONFIGFS_ITEM_LINK); | |
7063fbf2 | 362 | if (!err) { |
3d0f89bb | 363 | err = configfs_create(dentry, mode, init_symlink); |
fbc8d4c0 | 364 | if (err) { |
3d0f89bb JB |
365 | struct configfs_dirent *sd = dentry->d_fsdata; |
366 | if (sd) { | |
6f610764 | 367 | spin_lock(&configfs_dirent_lock); |
3d0f89bb | 368 | list_del_init(&sd->s_sibling); |
6f610764 | 369 | spin_unlock(&configfs_dirent_lock); |
3d0f89bb JB |
370 | configfs_put(sd); |
371 | } | |
372 | } | |
7063fbf2 JB |
373 | } |
374 | return err; | |
375 | } | |
376 | ||
377 | static void remove_dir(struct dentry * d) | |
378 | { | |
379 | struct dentry * parent = dget(d->d_parent); | |
380 | struct configfs_dirent * sd; | |
381 | ||
382 | sd = d->d_fsdata; | |
6f610764 | 383 | spin_lock(&configfs_dirent_lock); |
e7515d06 | 384 | list_del_init(&sd->s_sibling); |
6f610764 | 385 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
386 | configfs_put(sd); |
387 | if (d->d_inode) | |
388 | simple_rmdir(parent->d_inode,d); | |
389 | ||
b7ab39f6 | 390 | pr_debug(" o %s removing done (%d)\n",d->d_name.name, d->d_count); |
7063fbf2 JB |
391 | |
392 | dput(parent); | |
393 | } | |
394 | ||
395 | /** | |
396 | * configfs_remove_dir - remove an config_item's directory. | |
397 | * @item: config_item we're removing. | |
398 | * | |
399 | * The only thing special about this is that we remove any files in | |
400 | * the directory before we remove the directory, and we've inlined | |
401 | * what used to be configfs_rmdir() below, instead of calling separately. | |
2e2ce171 LR |
402 | * |
403 | * Caller holds the mutex of the item's inode | |
7063fbf2 JB |
404 | */ |
405 | ||
406 | static void configfs_remove_dir(struct config_item * item) | |
407 | { | |
408 | struct dentry * dentry = dget(item->ci_dentry); | |
409 | ||
410 | if (!dentry) | |
411 | return; | |
412 | ||
413 | remove_dir(dentry); | |
414 | /** | |
415 | * Drop reference from dget() on entrance. | |
416 | */ | |
417 | dput(dentry); | |
418 | } | |
419 | ||
420 | ||
421 | /* attaches attribute's configfs_dirent to the dentry corresponding to the | |
422 | * attribute file | |
423 | */ | |
424 | static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry) | |
425 | { | |
426 | struct configfs_attribute * attr = sd->s_element; | |
427 | int error; | |
428 | ||
3d0f89bb JB |
429 | dentry->d_fsdata = configfs_get(sd); |
430 | sd->s_dentry = dentry; | |
ce8d2cdf DH |
431 | error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG, |
432 | configfs_init_file); | |
3d0f89bb JB |
433 | if (error) { |
434 | configfs_put(sd); | |
7063fbf2 | 435 | return error; |
3d0f89bb | 436 | } |
7063fbf2 | 437 | |
7063fbf2 JB |
438 | d_rehash(dentry); |
439 | ||
440 | return 0; | |
441 | } | |
442 | ||
443 | static struct dentry * configfs_lookup(struct inode *dir, | |
444 | struct dentry *dentry, | |
00cd8dd3 | 445 | unsigned int flags) |
7063fbf2 JB |
446 | { |
447 | struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata; | |
448 | struct configfs_dirent * sd; | |
449 | int found = 0; | |
2a109f2a LR |
450 | int err; |
451 | ||
452 | /* | |
453 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
454 | * being attached | |
455 | * | |
456 | * This forbids userspace to read/write attributes of items which may | |
457 | * not complete their initialization, since the dentries of the | |
458 | * attributes won't be instantiated. | |
459 | */ | |
460 | err = -ENOENT; | |
461 | if (!configfs_dirent_is_ready(parent_sd)) | |
462 | goto out; | |
7063fbf2 JB |
463 | |
464 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
465 | if (sd->s_type & CONFIGFS_NOT_PINNED) { | |
466 | const unsigned char * name = configfs_get_name(sd); | |
467 | ||
468 | if (strcmp(name, dentry->d_name.name)) | |
469 | continue; | |
470 | ||
471 | found = 1; | |
472 | err = configfs_attach_attr(sd, dentry); | |
473 | break; | |
474 | } | |
475 | } | |
476 | ||
477 | if (!found) { | |
478 | /* | |
479 | * If it doesn't exist and it isn't a NOT_PINNED item, | |
480 | * it must be negative. | |
481 | */ | |
fbc8d4c0 NP |
482 | if (dentry->d_name.len > NAME_MAX) |
483 | return ERR_PTR(-ENAMETOOLONG); | |
fbc8d4c0 NP |
484 | d_add(dentry, NULL); |
485 | return NULL; | |
7063fbf2 JB |
486 | } |
487 | ||
2a109f2a | 488 | out: |
7063fbf2 JB |
489 | return ERR_PTR(err); |
490 | } | |
491 | ||
492 | /* | |
493 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are | |
b3e76af8 LR |
494 | * attributes and are removed by rmdir(). We recurse, setting |
495 | * CONFIGFS_USET_DROPPING on all children that are candidates for | |
496 | * default detach. | |
497 | * If there is an error, the caller will reset the flags via | |
498 | * configfs_detach_rollback(). | |
7063fbf2 | 499 | */ |
6d8344ba | 500 | static int configfs_detach_prep(struct dentry *dentry, struct mutex **wait_mutex) |
7063fbf2 JB |
501 | { |
502 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
503 | struct configfs_dirent *sd; | |
504 | int ret; | |
505 | ||
4768e9b1 LR |
506 | /* Mark that we're trying to drop the group */ |
507 | parent_sd->s_type |= CONFIGFS_USET_DROPPING; | |
508 | ||
7063fbf2 JB |
509 | ret = -EBUSY; |
510 | if (!list_empty(&parent_sd->s_links)) | |
511 | goto out; | |
512 | ||
513 | ret = 0; | |
514 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
99cefda4 LR |
515 | if (!sd->s_element || |
516 | (sd->s_type & CONFIGFS_NOT_PINNED)) | |
7063fbf2 JB |
517 | continue; |
518 | if (sd->s_type & CONFIGFS_USET_DEFAULT) { | |
6d8344ba LR |
519 | /* Abort if racing with mkdir() */ |
520 | if (sd->s_type & CONFIGFS_USET_IN_MKDIR) { | |
521 | if (wait_mutex) | |
522 | *wait_mutex = &sd->s_dentry->d_inode->i_mutex; | |
523 | return -EAGAIN; | |
524 | } | |
7063fbf2 | 525 | |
631d1feb JB |
526 | /* |
527 | * Yup, recursive. If there's a problem, blame | |
528 | * deep nesting of default_groups | |
529 | */ | |
6d8344ba | 530 | ret = configfs_detach_prep(sd->s_dentry, wait_mutex); |
7063fbf2 | 531 | if (!ret) |
e7515d06 | 532 | continue; |
7063fbf2 JB |
533 | } else |
534 | ret = -ENOTEMPTY; | |
535 | ||
536 | break; | |
537 | } | |
538 | ||
539 | out: | |
540 | return ret; | |
541 | } | |
542 | ||
543 | /* | |
b3e76af8 | 544 | * Walk the tree, resetting CONFIGFS_USET_DROPPING wherever it was |
7063fbf2 JB |
545 | * set. |
546 | */ | |
547 | static void configfs_detach_rollback(struct dentry *dentry) | |
548 | { | |
549 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
550 | struct configfs_dirent *sd; | |
551 | ||
4768e9b1 LR |
552 | parent_sd->s_type &= ~CONFIGFS_USET_DROPPING; |
553 | ||
554 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) | |
555 | if (sd->s_type & CONFIGFS_USET_DEFAULT) | |
7063fbf2 | 556 | configfs_detach_rollback(sd->s_dentry); |
7063fbf2 JB |
557 | } |
558 | ||
559 | static void detach_attrs(struct config_item * item) | |
560 | { | |
561 | struct dentry * dentry = dget(item->ci_dentry); | |
562 | struct configfs_dirent * parent_sd; | |
563 | struct configfs_dirent * sd, * tmp; | |
564 | ||
565 | if (!dentry) | |
566 | return; | |
567 | ||
568 | pr_debug("configfs %s: dropping attrs for dir\n", | |
569 | dentry->d_name.name); | |
570 | ||
571 | parent_sd = dentry->d_fsdata; | |
572 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
573 | if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED)) | |
574 | continue; | |
6f610764 | 575 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 576 | list_del_init(&sd->s_sibling); |
6f610764 | 577 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
578 | configfs_drop_dentry(sd, dentry); |
579 | configfs_put(sd); | |
580 | } | |
581 | ||
582 | /** | |
583 | * Drop reference from dget() on entrance. | |
584 | */ | |
585 | dput(dentry); | |
586 | } | |
587 | ||
588 | static int populate_attrs(struct config_item *item) | |
589 | { | |
590 | struct config_item_type *t = item->ci_type; | |
591 | struct configfs_attribute *attr; | |
592 | int error = 0; | |
593 | int i; | |
594 | ||
595 | if (!t) | |
596 | return -EINVAL; | |
597 | if (t->ct_attrs) { | |
598 | for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) { | |
599 | if ((error = configfs_create_file(item, attr))) | |
600 | break; | |
601 | } | |
602 | } | |
603 | ||
604 | if (error) | |
605 | detach_attrs(item); | |
606 | ||
607 | return error; | |
608 | } | |
609 | ||
610 | static int configfs_attach_group(struct config_item *parent_item, | |
611 | struct config_item *item, | |
612 | struct dentry *dentry); | |
613 | static void configfs_detach_group(struct config_item *item); | |
614 | ||
615 | static void detach_groups(struct config_group *group) | |
616 | { | |
617 | struct dentry * dentry = dget(group->cg_item.ci_dentry); | |
618 | struct dentry *child; | |
619 | struct configfs_dirent *parent_sd; | |
620 | struct configfs_dirent *sd, *tmp; | |
621 | ||
622 | if (!dentry) | |
623 | return; | |
624 | ||
625 | parent_sd = dentry->d_fsdata; | |
626 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
627 | if (!sd->s_element || | |
628 | !(sd->s_type & CONFIGFS_USET_DEFAULT)) | |
629 | continue; | |
630 | ||
631 | child = sd->s_dentry; | |
632 | ||
b3e76af8 LR |
633 | mutex_lock(&child->d_inode->i_mutex); |
634 | ||
7063fbf2 JB |
635 | configfs_detach_group(sd->s_element); |
636 | child->d_inode->i_flags |= S_DEAD; | |
d83c49f3 | 637 | dont_mount(child); |
7063fbf2 | 638 | |
b3e76af8 | 639 | mutex_unlock(&child->d_inode->i_mutex); |
7063fbf2 JB |
640 | |
641 | d_delete(child); | |
642 | dput(child); | |
643 | } | |
644 | ||
645 | /** | |
646 | * Drop reference from dget() on entrance. | |
647 | */ | |
648 | dput(dentry); | |
649 | } | |
650 | ||
651 | /* | |
652 | * This fakes mkdir(2) on a default_groups[] entry. It | |
653 | * creates a dentry, attachs it, and then does fixup | |
654 | * on the sd->s_type. | |
655 | * | |
656 | * We could, perhaps, tweak our parent's ->mkdir for a minute and | |
657 | * try using vfs_mkdir. Just a thought. | |
658 | */ | |
659 | static int create_default_group(struct config_group *parent_group, | |
660 | struct config_group *group) | |
661 | { | |
662 | int ret; | |
663 | struct qstr name; | |
664 | struct configfs_dirent *sd; | |
665 | /* We trust the caller holds a reference to parent */ | |
666 | struct dentry *child, *parent = parent_group->cg_item.ci_dentry; | |
667 | ||
668 | if (!group->cg_item.ci_name) | |
669 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
670 | name.name = group->cg_item.ci_name; | |
671 | name.len = strlen(name.name); | |
672 | name.hash = full_name_hash(name.name, name.len); | |
673 | ||
674 | ret = -ENOMEM; | |
675 | child = d_alloc(parent, &name); | |
676 | if (child) { | |
677 | d_add(child, NULL); | |
678 | ||
679 | ret = configfs_attach_group(&parent_group->cg_item, | |
680 | &group->cg_item, child); | |
681 | if (!ret) { | |
682 | sd = child->d_fsdata; | |
683 | sd->s_type |= CONFIGFS_USET_DEFAULT; | |
684 | } else { | |
df7f9967 JB |
685 | BUG_ON(child->d_inode); |
686 | d_drop(child); | |
7063fbf2 JB |
687 | dput(child); |
688 | } | |
689 | } | |
690 | ||
691 | return ret; | |
692 | } | |
693 | ||
694 | static int populate_groups(struct config_group *group) | |
695 | { | |
696 | struct config_group *new_group; | |
7063fbf2 JB |
697 | int ret = 0; |
698 | int i; | |
699 | ||
cbca692c | 700 | if (group->default_groups) { |
7063fbf2 JB |
701 | for (i = 0; group->default_groups[i]; i++) { |
702 | new_group = group->default_groups[i]; | |
703 | ||
704 | ret = create_default_group(group, new_group); | |
2e2ce171 LR |
705 | if (ret) { |
706 | detach_groups(group); | |
7063fbf2 | 707 | break; |
2e2ce171 | 708 | } |
7063fbf2 | 709 | } |
7063fbf2 JB |
710 | } |
711 | ||
7063fbf2 JB |
712 | return ret; |
713 | } | |
714 | ||
715 | /* | |
716 | * All of link_obj/unlink_obj/link_group/unlink_group require that | |
e6bd07ae | 717 | * subsys->su_mutex is held. |
7063fbf2 JB |
718 | */ |
719 | ||
720 | static void unlink_obj(struct config_item *item) | |
721 | { | |
722 | struct config_group *group; | |
723 | ||
724 | group = item->ci_group; | |
725 | if (group) { | |
726 | list_del_init(&item->ci_entry); | |
727 | ||
728 | item->ci_group = NULL; | |
729 | item->ci_parent = NULL; | |
eed7a0db JB |
730 | |
731 | /* Drop the reference for ci_entry */ | |
7063fbf2 JB |
732 | config_item_put(item); |
733 | ||
eed7a0db | 734 | /* Drop the reference for ci_parent */ |
7063fbf2 JB |
735 | config_group_put(group); |
736 | } | |
737 | } | |
738 | ||
739 | static void link_obj(struct config_item *parent_item, struct config_item *item) | |
740 | { | |
eed7a0db JB |
741 | /* |
742 | * Parent seems redundant with group, but it makes certain | |
743 | * traversals much nicer. | |
744 | */ | |
7063fbf2 | 745 | item->ci_parent = parent_item; |
eed7a0db JB |
746 | |
747 | /* | |
748 | * We hold a reference on the parent for the child's ci_parent | |
749 | * link. | |
750 | */ | |
7063fbf2 JB |
751 | item->ci_group = config_group_get(to_config_group(parent_item)); |
752 | list_add_tail(&item->ci_entry, &item->ci_group->cg_children); | |
753 | ||
eed7a0db JB |
754 | /* |
755 | * We hold a reference on the child for ci_entry on the parent's | |
756 | * cg_children | |
757 | */ | |
7063fbf2 JB |
758 | config_item_get(item); |
759 | } | |
760 | ||
761 | static void unlink_group(struct config_group *group) | |
762 | { | |
763 | int i; | |
764 | struct config_group *new_group; | |
765 | ||
766 | if (group->default_groups) { | |
767 | for (i = 0; group->default_groups[i]; i++) { | |
768 | new_group = group->default_groups[i]; | |
769 | unlink_group(new_group); | |
770 | } | |
771 | } | |
772 | ||
773 | group->cg_subsys = NULL; | |
774 | unlink_obj(&group->cg_item); | |
775 | } | |
776 | ||
777 | static void link_group(struct config_group *parent_group, struct config_group *group) | |
778 | { | |
779 | int i; | |
780 | struct config_group *new_group; | |
781 | struct configfs_subsystem *subsys = NULL; /* gcc is a turd */ | |
782 | ||
783 | link_obj(&parent_group->cg_item, &group->cg_item); | |
784 | ||
785 | if (parent_group->cg_subsys) | |
786 | subsys = parent_group->cg_subsys; | |
787 | else if (configfs_is_root(&parent_group->cg_item)) | |
788 | subsys = to_configfs_subsystem(group); | |
789 | else | |
790 | BUG(); | |
791 | group->cg_subsys = subsys; | |
792 | ||
793 | if (group->default_groups) { | |
794 | for (i = 0; group->default_groups[i]; i++) { | |
795 | new_group = group->default_groups[i]; | |
796 | link_group(group, new_group); | |
797 | } | |
798 | } | |
799 | } | |
800 | ||
801 | /* | |
802 | * The goal is that configfs_attach_item() (and | |
803 | * configfs_attach_group()) can be called from either the VFS or this | |
804 | * module. That is, they assume that the items have been created, | |
805 | * the dentry allocated, and the dcache is all ready to go. | |
806 | * | |
807 | * If they fail, they must clean up after themselves as if they | |
808 | * had never been called. The caller (VFS or local function) will | |
809 | * handle cleaning up the dcache bits. | |
810 | * | |
811 | * configfs_detach_group() and configfs_detach_item() behave similarly on | |
812 | * the way out. They assume that the proper semaphores are held, they | |
813 | * clean up the configfs items, and they expect their callers will | |
814 | * handle the dcache bits. | |
815 | */ | |
816 | static int configfs_attach_item(struct config_item *parent_item, | |
817 | struct config_item *item, | |
818 | struct dentry *dentry) | |
819 | { | |
820 | int ret; | |
821 | ||
822 | ret = configfs_create_dir(item, dentry); | |
823 | if (!ret) { | |
824 | ret = populate_attrs(item); | |
825 | if (ret) { | |
2e2ce171 LR |
826 | /* |
827 | * We are going to remove an inode and its dentry but | |
828 | * the VFS may already have hit and used them. Thus, | |
829 | * we must lock them as rmdir() would. | |
830 | */ | |
831 | mutex_lock(&dentry->d_inode->i_mutex); | |
7063fbf2 | 832 | configfs_remove_dir(item); |
2e2ce171 | 833 | dentry->d_inode->i_flags |= S_DEAD; |
d83c49f3 | 834 | dont_mount(dentry); |
2e2ce171 | 835 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
836 | d_delete(dentry); |
837 | } | |
838 | } | |
839 | ||
840 | return ret; | |
841 | } | |
842 | ||
2e2ce171 | 843 | /* Caller holds the mutex of the item's inode */ |
7063fbf2 JB |
844 | static void configfs_detach_item(struct config_item *item) |
845 | { | |
846 | detach_attrs(item); | |
847 | configfs_remove_dir(item); | |
848 | } | |
849 | ||
850 | static int configfs_attach_group(struct config_item *parent_item, | |
851 | struct config_item *item, | |
852 | struct dentry *dentry) | |
853 | { | |
854 | int ret; | |
855 | struct configfs_dirent *sd; | |
856 | ||
857 | ret = configfs_attach_item(parent_item, item, dentry); | |
858 | if (!ret) { | |
859 | sd = dentry->d_fsdata; | |
860 | sd->s_type |= CONFIGFS_USET_DIR; | |
861 | ||
2e2ce171 LR |
862 | /* |
863 | * FYI, we're faking mkdir in populate_groups() | |
864 | * We must lock the group's inode to avoid races with the VFS | |
865 | * which can already hit the inode and try to add/remove entries | |
866 | * under it. | |
867 | * | |
868 | * We must also lock the inode to remove it safely in case of | |
869 | * error, as rmdir() would. | |
870 | */ | |
871 | mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); | |
e74cc06d | 872 | configfs_adjust_dir_dirent_depth_before_populate(sd); |
7063fbf2 JB |
873 | ret = populate_groups(to_config_group(item)); |
874 | if (ret) { | |
875 | configfs_detach_item(item); | |
2e2ce171 | 876 | dentry->d_inode->i_flags |= S_DEAD; |
d83c49f3 | 877 | dont_mount(dentry); |
7063fbf2 | 878 | } |
e74cc06d | 879 | configfs_adjust_dir_dirent_depth_after_populate(sd); |
2e2ce171 LR |
880 | mutex_unlock(&dentry->d_inode->i_mutex); |
881 | if (ret) | |
882 | d_delete(dentry); | |
7063fbf2 JB |
883 | } |
884 | ||
885 | return ret; | |
886 | } | |
887 | ||
2e2ce171 | 888 | /* Caller holds the mutex of the group's inode */ |
7063fbf2 JB |
889 | static void configfs_detach_group(struct config_item *item) |
890 | { | |
891 | detach_groups(to_config_group(item)); | |
892 | configfs_detach_item(item); | |
893 | } | |
894 | ||
299894cc JB |
895 | /* |
896 | * After the item has been detached from the filesystem view, we are | |
897 | * ready to tear it out of the hierarchy. Notify the client before | |
898 | * we do that so they can perform any cleanup that requires | |
899 | * navigating the hierarchy. A client does not need to provide this | |
900 | * callback. The subsystem semaphore MUST be held by the caller, and | |
901 | * references must be valid for both items. It also assumes the | |
902 | * caller has validated ci_type. | |
903 | */ | |
904 | static void client_disconnect_notify(struct config_item *parent_item, | |
905 | struct config_item *item) | |
906 | { | |
907 | struct config_item_type *type; | |
908 | ||
909 | type = parent_item->ci_type; | |
910 | BUG_ON(!type); | |
911 | ||
912 | if (type->ct_group_ops && type->ct_group_ops->disconnect_notify) | |
913 | type->ct_group_ops->disconnect_notify(to_config_group(parent_item), | |
914 | item); | |
915 | } | |
916 | ||
7063fbf2 JB |
917 | /* |
918 | * Drop the initial reference from make_item()/make_group() | |
919 | * This function assumes that reference is held on item | |
920 | * and that item holds a valid reference to the parent. Also, it | |
921 | * assumes the caller has validated ci_type. | |
922 | */ | |
923 | static void client_drop_item(struct config_item *parent_item, | |
924 | struct config_item *item) | |
925 | { | |
926 | struct config_item_type *type; | |
927 | ||
928 | type = parent_item->ci_type; | |
929 | BUG_ON(!type); | |
930 | ||
eed7a0db JB |
931 | /* |
932 | * If ->drop_item() exists, it is responsible for the | |
933 | * config_item_put(). | |
934 | */ | |
7063fbf2 JB |
935 | if (type->ct_group_ops && type->ct_group_ops->drop_item) |
936 | type->ct_group_ops->drop_item(to_config_group(parent_item), | |
299894cc | 937 | item); |
7063fbf2 JB |
938 | else |
939 | config_item_put(item); | |
940 | } | |
941 | ||
631d1feb JB |
942 | #ifdef DEBUG |
943 | static void configfs_dump_one(struct configfs_dirent *sd, int level) | |
944 | { | |
945 | printk(KERN_INFO "%*s\"%s\":\n", level, " ", configfs_get_name(sd)); | |
946 | ||
947 | #define type_print(_type) if (sd->s_type & _type) printk(KERN_INFO "%*s %s\n", level, " ", #_type); | |
948 | type_print(CONFIGFS_ROOT); | |
949 | type_print(CONFIGFS_DIR); | |
950 | type_print(CONFIGFS_ITEM_ATTR); | |
951 | type_print(CONFIGFS_ITEM_LINK); | |
952 | type_print(CONFIGFS_USET_DIR); | |
953 | type_print(CONFIGFS_USET_DEFAULT); | |
954 | type_print(CONFIGFS_USET_DROPPING); | |
955 | #undef type_print | |
956 | } | |
957 | ||
958 | static int configfs_dump(struct configfs_dirent *sd, int level) | |
959 | { | |
960 | struct configfs_dirent *child_sd; | |
961 | int ret = 0; | |
962 | ||
963 | configfs_dump_one(sd, level); | |
964 | ||
965 | if (!(sd->s_type & (CONFIGFS_DIR|CONFIGFS_ROOT))) | |
966 | return 0; | |
967 | ||
968 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) { | |
969 | ret = configfs_dump(child_sd, level + 2); | |
970 | if (ret) | |
971 | break; | |
972 | } | |
973 | ||
974 | return ret; | |
975 | } | |
976 | #endif | |
977 | ||
978 | ||
979 | /* | |
980 | * configfs_depend_item() and configfs_undepend_item() | |
981 | * | |
982 | * WARNING: Do not call these from a configfs callback! | |
983 | * | |
984 | * This describes these functions and their helpers. | |
985 | * | |
986 | * Allow another kernel system to depend on a config_item. If this | |
25985edc | 987 | * happens, the item cannot go away until the dependent can live without |
631d1feb JB |
988 | * it. The idea is to give client modules as simple an interface as |
989 | * possible. When a system asks them to depend on an item, they just | |
990 | * call configfs_depend_item(). If the item is live and the client | |
991 | * driver is in good shape, we'll happily do the work for them. | |
992 | * | |
993 | * Why is the locking complex? Because configfs uses the VFS to handle | |
994 | * all locking, but this function is called outside the normal | |
995 | * VFS->configfs path. So it must take VFS locks to prevent the | |
996 | * VFS->configfs stuff (configfs_mkdir(), configfs_rmdir(), etc). This is | |
997 | * why you can't call these functions underneath configfs callbacks. | |
998 | * | |
999 | * Note, btw, that this can be called at *any* time, even when a configfs | |
1000 | * subsystem isn't registered, or when configfs is loading or unloading. | |
1001 | * Just like configfs_register_subsystem(). So we take the same | |
420118ca LR |
1002 | * precautions. We pin the filesystem. We lock configfs_dirent_lock. |
1003 | * If we can find the target item in the | |
631d1feb | 1004 | * configfs tree, it must be part of the subsystem tree as well, so we |
420118ca LR |
1005 | * do not need the subsystem semaphore. Holding configfs_dirent_lock helps |
1006 | * locking out mkdir() and rmdir(), who might be racing us. | |
631d1feb JB |
1007 | */ |
1008 | ||
1009 | /* | |
1010 | * configfs_depend_prep() | |
1011 | * | |
1012 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are | |
1013 | * attributes. This is similar but not the same to configfs_detach_prep(). | |
1014 | * Note that configfs_detach_prep() expects the parent to be locked when it | |
1015 | * is called, but we lock the parent *inside* configfs_depend_prep(). We | |
1016 | * do that so we can unlock it if we find nothing. | |
1017 | * | |
1018 | * Here we do a depth-first search of the dentry hierarchy looking for | |
420118ca LR |
1019 | * our object. |
1020 | * We deliberately ignore items tagged as dropping since they are virtually | |
1021 | * dead, as well as items in the middle of attachment since they virtually | |
1022 | * do not exist yet. This completes the locking out of racing mkdir() and | |
1023 | * rmdir(). | |
1024 | * Note: subdirectories in the middle of attachment start with s_type = | |
1025 | * CONFIGFS_DIR|CONFIGFS_USET_CREATING set by create_dir(). When | |
1026 | * CONFIGFS_USET_CREATING is set, we ignore the item. The actual set of | |
1027 | * s_type is in configfs_new_dirent(), which has configfs_dirent_lock. | |
631d1feb | 1028 | * |
420118ca | 1029 | * If the target is not found, -ENOENT is bubbled up. |
631d1feb JB |
1030 | * |
1031 | * This adds a requirement that all config_items be unique! | |
1032 | * | |
420118ca | 1033 | * This is recursive. There isn't |
631d1feb JB |
1034 | * much on the stack, though, so folks that need this function - be careful |
1035 | * about your stack! Patches will be accepted to make it iterative. | |
1036 | */ | |
1037 | static int configfs_depend_prep(struct dentry *origin, | |
1038 | struct config_item *target) | |
1039 | { | |
49deb4bc | 1040 | struct configfs_dirent *child_sd, *sd; |
631d1feb JB |
1041 | int ret = 0; |
1042 | ||
49deb4bc WY |
1043 | BUG_ON(!origin || !origin->d_fsdata); |
1044 | sd = origin->d_fsdata; | |
631d1feb | 1045 | |
631d1feb JB |
1046 | if (sd->s_element == target) /* Boo-yah */ |
1047 | goto out; | |
1048 | ||
1049 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) { | |
420118ca LR |
1050 | if ((child_sd->s_type & CONFIGFS_DIR) && |
1051 | !(child_sd->s_type & CONFIGFS_USET_DROPPING) && | |
1052 | !(child_sd->s_type & CONFIGFS_USET_CREATING)) { | |
631d1feb JB |
1053 | ret = configfs_depend_prep(child_sd->s_dentry, |
1054 | target); | |
1055 | if (!ret) | |
1056 | goto out; /* Child path boo-yah */ | |
1057 | } | |
1058 | } | |
1059 | ||
1060 | /* We looped all our children and didn't find target */ | |
631d1feb JB |
1061 | ret = -ENOENT; |
1062 | ||
1063 | out: | |
1064 | return ret; | |
1065 | } | |
1066 | ||
631d1feb JB |
1067 | int configfs_depend_item(struct configfs_subsystem *subsys, |
1068 | struct config_item *target) | |
1069 | { | |
1070 | int ret; | |
1071 | struct configfs_dirent *p, *root_sd, *subsys_sd = NULL; | |
1072 | struct config_item *s_item = &subsys->su_group.cg_item; | |
b7c177fc | 1073 | struct dentry *root; |
631d1feb JB |
1074 | |
1075 | /* | |
1076 | * Pin the configfs filesystem. This means we can safely access | |
1077 | * the root of the configfs filesystem. | |
1078 | */ | |
2a152ad3 AV |
1079 | root = configfs_pin_fs(); |
1080 | if (IS_ERR(root)) | |
1081 | return PTR_ERR(root); | |
631d1feb JB |
1082 | |
1083 | /* | |
1084 | * Next, lock the root directory. We're going to check that the | |
1085 | * subsystem is really registered, and so we need to lock out | |
1086 | * configfs_[un]register_subsystem(). | |
1087 | */ | |
b7c177fc | 1088 | mutex_lock(&root->d_inode->i_mutex); |
631d1feb | 1089 | |
b7c177fc | 1090 | root_sd = root->d_fsdata; |
631d1feb JB |
1091 | |
1092 | list_for_each_entry(p, &root_sd->s_children, s_sibling) { | |
1093 | if (p->s_type & CONFIGFS_DIR) { | |
1094 | if (p->s_element == s_item) { | |
1095 | subsys_sd = p; | |
1096 | break; | |
1097 | } | |
1098 | } | |
1099 | } | |
1100 | ||
1101 | if (!subsys_sd) { | |
1102 | ret = -ENOENT; | |
1103 | goto out_unlock_fs; | |
1104 | } | |
1105 | ||
1106 | /* Ok, now we can trust subsys/s_item */ | |
1107 | ||
420118ca LR |
1108 | spin_lock(&configfs_dirent_lock); |
1109 | /* Scan the tree, return 0 if found */ | |
631d1feb JB |
1110 | ret = configfs_depend_prep(subsys_sd->s_dentry, target); |
1111 | if (ret) | |
420118ca | 1112 | goto out_unlock_dirent_lock; |
631d1feb | 1113 | |
420118ca LR |
1114 | /* |
1115 | * We are sure that the item is not about to be removed by rmdir(), and | |
1116 | * not in the middle of attachment by mkdir(). | |
1117 | */ | |
631d1feb JB |
1118 | p = target->ci_dentry->d_fsdata; |
1119 | p->s_dependent_count += 1; | |
1120 | ||
420118ca LR |
1121 | out_unlock_dirent_lock: |
1122 | spin_unlock(&configfs_dirent_lock); | |
631d1feb | 1123 | out_unlock_fs: |
b7c177fc | 1124 | mutex_unlock(&root->d_inode->i_mutex); |
631d1feb JB |
1125 | |
1126 | /* | |
1127 | * If we succeeded, the fs is pinned via other methods. If not, | |
1128 | * we're done with it anyway. So release_fs() is always right. | |
1129 | */ | |
1130 | configfs_release_fs(); | |
1131 | ||
1132 | return ret; | |
1133 | } | |
1134 | EXPORT_SYMBOL(configfs_depend_item); | |
1135 | ||
1136 | /* | |
1137 | * Release the dependent linkage. This is much simpler than | |
1138 | * configfs_depend_item() because we know that that the client driver is | |
1139 | * pinned, thus the subsystem is pinned, and therefore configfs is pinned. | |
1140 | */ | |
1141 | void configfs_undepend_item(struct configfs_subsystem *subsys, | |
1142 | struct config_item *target) | |
1143 | { | |
1144 | struct configfs_dirent *sd; | |
1145 | ||
1146 | /* | |
420118ca LR |
1147 | * Since we can trust everything is pinned, we just need |
1148 | * configfs_dirent_lock. | |
631d1feb | 1149 | */ |
420118ca | 1150 | spin_lock(&configfs_dirent_lock); |
631d1feb JB |
1151 | |
1152 | sd = target->ci_dentry->d_fsdata; | |
1153 | BUG_ON(sd->s_dependent_count < 1); | |
1154 | ||
1155 | sd->s_dependent_count -= 1; | |
1156 | ||
1157 | /* | |
1158 | * After this unlock, we cannot trust the item to stay alive! | |
1159 | * DO NOT REFERENCE item after this unlock. | |
1160 | */ | |
420118ca | 1161 | spin_unlock(&configfs_dirent_lock); |
631d1feb JB |
1162 | } |
1163 | EXPORT_SYMBOL(configfs_undepend_item); | |
7063fbf2 | 1164 | |
18bb1db3 | 1165 | static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) |
7063fbf2 | 1166 | { |
a6795e9e JB |
1167 | int ret = 0; |
1168 | int module_got = 0; | |
1169 | struct config_group *group = NULL; | |
1170 | struct config_item *item = NULL; | |
7063fbf2 JB |
1171 | struct config_item *parent_item; |
1172 | struct configfs_subsystem *subsys; | |
1173 | struct configfs_dirent *sd; | |
1174 | struct config_item_type *type; | |
70526b67 | 1175 | struct module *subsys_owner = NULL, *new_item_owner = NULL; |
7063fbf2 JB |
1176 | char *name; |
1177 | ||
7063fbf2 | 1178 | sd = dentry->d_parent->d_fsdata; |
2a109f2a LR |
1179 | |
1180 | /* | |
1181 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
1182 | * being attached | |
1183 | */ | |
1184 | if (!configfs_dirent_is_ready(sd)) { | |
1185 | ret = -ENOENT; | |
1186 | goto out; | |
1187 | } | |
1188 | ||
84efad1a JB |
1189 | if (!(sd->s_type & CONFIGFS_USET_DIR)) { |
1190 | ret = -EPERM; | |
1191 | goto out; | |
1192 | } | |
7063fbf2 | 1193 | |
84efad1a | 1194 | /* Get a working ref for the duration of this function */ |
7063fbf2 JB |
1195 | parent_item = configfs_get_config_item(dentry->d_parent); |
1196 | type = parent_item->ci_type; | |
1197 | subsys = to_config_group(parent_item)->cg_subsys; | |
1198 | BUG_ON(!subsys); | |
1199 | ||
1200 | if (!type || !type->ct_group_ops || | |
1201 | (!type->ct_group_ops->make_group && | |
1202 | !type->ct_group_ops->make_item)) { | |
84efad1a JB |
1203 | ret = -EPERM; /* Lack-of-mkdir returns -EPERM */ |
1204 | goto out_put; | |
7063fbf2 JB |
1205 | } |
1206 | ||
70526b67 JB |
1207 | /* |
1208 | * The subsystem may belong to a different module than the item | |
1209 | * being created. We don't want to safely pin the new item but | |
1210 | * fail to pin the subsystem it sits under. | |
1211 | */ | |
1212 | if (!subsys->su_group.cg_item.ci_type) { | |
1213 | ret = -EINVAL; | |
1214 | goto out_put; | |
1215 | } | |
1216 | subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; | |
1217 | if (!try_module_get(subsys_owner)) { | |
1218 | ret = -EINVAL; | |
1219 | goto out_put; | |
1220 | } | |
1221 | ||
7063fbf2 JB |
1222 | name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL); |
1223 | if (!name) { | |
84efad1a | 1224 | ret = -ENOMEM; |
70526b67 | 1225 | goto out_subsys_put; |
7063fbf2 | 1226 | } |
84efad1a | 1227 | |
7063fbf2 JB |
1228 | snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name); |
1229 | ||
e6bd07ae | 1230 | mutex_lock(&subsys->su_mutex); |
7063fbf2 | 1231 | if (type->ct_group_ops->make_group) { |
f89ab861 | 1232 | group = type->ct_group_ops->make_group(to_config_group(parent_item), name); |
a6795e9e JB |
1233 | if (!group) |
1234 | group = ERR_PTR(-ENOMEM); | |
1235 | if (!IS_ERR(group)) { | |
7063fbf2 JB |
1236 | link_group(to_config_group(parent_item), group); |
1237 | item = &group->cg_item; | |
a6795e9e JB |
1238 | } else |
1239 | ret = PTR_ERR(group); | |
7063fbf2 | 1240 | } else { |
f89ab861 | 1241 | item = type->ct_group_ops->make_item(to_config_group(parent_item), name); |
a6795e9e JB |
1242 | if (!item) |
1243 | item = ERR_PTR(-ENOMEM); | |
1244 | if (!IS_ERR(item)) | |
7063fbf2 | 1245 | link_obj(parent_item, item); |
a6795e9e JB |
1246 | else |
1247 | ret = PTR_ERR(item); | |
7063fbf2 | 1248 | } |
e6bd07ae | 1249 | mutex_unlock(&subsys->su_mutex); |
7063fbf2 JB |
1250 | |
1251 | kfree(name); | |
a6795e9e | 1252 | if (ret) { |
eed7a0db | 1253 | /* |
dacdd0e0 | 1254 | * If ret != 0, then link_obj() was never called. |
eed7a0db JB |
1255 | * There are no extra references to clean up. |
1256 | */ | |
70526b67 | 1257 | goto out_subsys_put; |
7063fbf2 JB |
1258 | } |
1259 | ||
eed7a0db JB |
1260 | /* |
1261 | * link_obj() has been called (via link_group() for groups). | |
1262 | * From here on out, errors must clean that up. | |
1263 | */ | |
1264 | ||
7063fbf2 | 1265 | type = item->ci_type; |
eed7a0db JB |
1266 | if (!type) { |
1267 | ret = -EINVAL; | |
1268 | goto out_unlink; | |
1269 | } | |
7063fbf2 | 1270 | |
70526b67 JB |
1271 | new_item_owner = type->ct_owner; |
1272 | if (!try_module_get(new_item_owner)) { | |
eed7a0db JB |
1273 | ret = -EINVAL; |
1274 | goto out_unlink; | |
1275 | } | |
7063fbf2 | 1276 | |
eed7a0db JB |
1277 | /* |
1278 | * I hate doing it this way, but if there is | |
1279 | * an error, module_put() probably should | |
1280 | * happen after any cleanup. | |
1281 | */ | |
1282 | module_got = 1; | |
1283 | ||
6d8344ba LR |
1284 | /* |
1285 | * Make racing rmdir() fail if it did not tag parent with | |
1286 | * CONFIGFS_USET_DROPPING | |
1287 | * Note: if CONFIGFS_USET_DROPPING is already set, attach_group() will | |
1288 | * fail and let rmdir() terminate correctly | |
1289 | */ | |
1290 | spin_lock(&configfs_dirent_lock); | |
1291 | /* This will make configfs_detach_prep() fail */ | |
1292 | sd->s_type |= CONFIGFS_USET_IN_MKDIR; | |
1293 | spin_unlock(&configfs_dirent_lock); | |
1294 | ||
eed7a0db JB |
1295 | if (group) |
1296 | ret = configfs_attach_group(parent_item, item, dentry); | |
1297 | else | |
1298 | ret = configfs_attach_item(parent_item, item, dentry); | |
1299 | ||
6d8344ba LR |
1300 | spin_lock(&configfs_dirent_lock); |
1301 | sd->s_type &= ~CONFIGFS_USET_IN_MKDIR; | |
2a109f2a LR |
1302 | if (!ret) |
1303 | configfs_dir_set_ready(dentry->d_fsdata); | |
6d8344ba LR |
1304 | spin_unlock(&configfs_dirent_lock); |
1305 | ||
eed7a0db JB |
1306 | out_unlink: |
1307 | if (ret) { | |
1308 | /* Tear down everything we built up */ | |
e6bd07ae | 1309 | mutex_lock(&subsys->su_mutex); |
299894cc JB |
1310 | |
1311 | client_disconnect_notify(parent_item, item); | |
eed7a0db JB |
1312 | if (group) |
1313 | unlink_group(group); | |
1314 | else | |
1315 | unlink_obj(item); | |
1316 | client_drop_item(parent_item, item); | |
299894cc | 1317 | |
e6bd07ae | 1318 | mutex_unlock(&subsys->su_mutex); |
eed7a0db JB |
1319 | |
1320 | if (module_got) | |
70526b67 | 1321 | module_put(new_item_owner); |
7063fbf2 JB |
1322 | } |
1323 | ||
70526b67 JB |
1324 | out_subsys_put: |
1325 | if (ret) | |
1326 | module_put(subsys_owner); | |
1327 | ||
84efad1a JB |
1328 | out_put: |
1329 | /* | |
eed7a0db JB |
1330 | * link_obj()/link_group() took a reference from child->parent, |
1331 | * so the parent is safely pinned. We can drop our working | |
1332 | * reference. | |
84efad1a JB |
1333 | */ |
1334 | config_item_put(parent_item); | |
1335 | ||
1336 | out: | |
7063fbf2 JB |
1337 | return ret; |
1338 | } | |
1339 | ||
1340 | static int configfs_rmdir(struct inode *dir, struct dentry *dentry) | |
1341 | { | |
1342 | struct config_item *parent_item; | |
1343 | struct config_item *item; | |
1344 | struct configfs_subsystem *subsys; | |
1345 | struct configfs_dirent *sd; | |
70526b67 | 1346 | struct module *subsys_owner = NULL, *dead_item_owner = NULL; |
7063fbf2 JB |
1347 | int ret; |
1348 | ||
7063fbf2 JB |
1349 | sd = dentry->d_fsdata; |
1350 | if (sd->s_type & CONFIGFS_USET_DEFAULT) | |
1351 | return -EPERM; | |
1352 | ||
84efad1a | 1353 | /* Get a working ref until we have the child */ |
7063fbf2 JB |
1354 | parent_item = configfs_get_config_item(dentry->d_parent); |
1355 | subsys = to_config_group(parent_item)->cg_subsys; | |
1356 | BUG_ON(!subsys); | |
1357 | ||
1358 | if (!parent_item->ci_type) { | |
1359 | config_item_put(parent_item); | |
1360 | return -EINVAL; | |
1361 | } | |
1362 | ||
70526b67 JB |
1363 | /* configfs_mkdir() shouldn't have allowed this */ |
1364 | BUG_ON(!subsys->su_group.cg_item.ci_type); | |
1365 | subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; | |
1366 | ||
9a73d78c LR |
1367 | /* |
1368 | * Ensure that no racing symlink() will make detach_prep() fail while | |
1369 | * the new link is temporarily attached | |
1370 | */ | |
6d8344ba LR |
1371 | do { |
1372 | struct mutex *wait_mutex; | |
1373 | ||
de6bf18e LR |
1374 | mutex_lock(&configfs_symlink_mutex); |
1375 | spin_lock(&configfs_dirent_lock); | |
420118ca LR |
1376 | /* |
1377 | * Here's where we check for dependents. We're protected by | |
1378 | * configfs_dirent_lock. | |
1379 | * If no dependent, atomically tag the item as dropping. | |
1380 | */ | |
1381 | ret = sd->s_dependent_count ? -EBUSY : 0; | |
1382 | if (!ret) { | |
1383 | ret = configfs_detach_prep(dentry, &wait_mutex); | |
1384 | if (ret) | |
1385 | configfs_detach_rollback(dentry); | |
1386 | } | |
de6bf18e LR |
1387 | spin_unlock(&configfs_dirent_lock); |
1388 | mutex_unlock(&configfs_symlink_mutex); | |
1389 | ||
1390 | if (ret) { | |
6d8344ba LR |
1391 | if (ret != -EAGAIN) { |
1392 | config_item_put(parent_item); | |
1393 | return ret; | |
1394 | } | |
1395 | ||
1396 | /* Wait until the racing operation terminates */ | |
1397 | mutex_lock(wait_mutex); | |
1398 | mutex_unlock(wait_mutex); | |
6d8344ba LR |
1399 | } |
1400 | } while (ret == -EAGAIN); | |
7063fbf2 | 1401 | |
84efad1a | 1402 | /* Get a working ref for the duration of this function */ |
7063fbf2 JB |
1403 | item = configfs_get_config_item(dentry); |
1404 | ||
1405 | /* Drop reference from above, item already holds one. */ | |
1406 | config_item_put(parent_item); | |
1407 | ||
1408 | if (item->ci_type) | |
70526b67 | 1409 | dead_item_owner = item->ci_type->ct_owner; |
7063fbf2 JB |
1410 | |
1411 | if (sd->s_type & CONFIGFS_USET_DIR) { | |
1412 | configfs_detach_group(item); | |
1413 | ||
e6bd07ae | 1414 | mutex_lock(&subsys->su_mutex); |
299894cc | 1415 | client_disconnect_notify(parent_item, item); |
7063fbf2 JB |
1416 | unlink_group(to_config_group(item)); |
1417 | } else { | |
1418 | configfs_detach_item(item); | |
1419 | ||
e6bd07ae | 1420 | mutex_lock(&subsys->su_mutex); |
299894cc | 1421 | client_disconnect_notify(parent_item, item); |
7063fbf2 JB |
1422 | unlink_obj(item); |
1423 | } | |
1424 | ||
1425 | client_drop_item(parent_item, item); | |
e6bd07ae | 1426 | mutex_unlock(&subsys->su_mutex); |
7063fbf2 JB |
1427 | |
1428 | /* Drop our reference from above */ | |
1429 | config_item_put(item); | |
1430 | ||
70526b67 JB |
1431 | module_put(dead_item_owner); |
1432 | module_put(subsys_owner); | |
7063fbf2 JB |
1433 | |
1434 | return 0; | |
1435 | } | |
1436 | ||
754661f1 | 1437 | const struct inode_operations configfs_dir_inode_operations = { |
7063fbf2 JB |
1438 | .mkdir = configfs_mkdir, |
1439 | .rmdir = configfs_rmdir, | |
1440 | .symlink = configfs_symlink, | |
1441 | .unlink = configfs_unlink, | |
1442 | .lookup = configfs_lookup, | |
3d0f89bb | 1443 | .setattr = configfs_setattr, |
7063fbf2 JB |
1444 | }; |
1445 | ||
81d44ed1 AV |
1446 | const struct inode_operations configfs_root_inode_operations = { |
1447 | .lookup = configfs_lookup, | |
1448 | .setattr = configfs_setattr, | |
1449 | }; | |
1450 | ||
7063fbf2 JB |
1451 | #if 0 |
1452 | int configfs_rename_dir(struct config_item * item, const char *new_name) | |
1453 | { | |
1454 | int error = 0; | |
1455 | struct dentry * new_dentry, * parent; | |
1456 | ||
1457 | if (!strcmp(config_item_name(item), new_name)) | |
1458 | return -EINVAL; | |
1459 | ||
1460 | if (!item->parent) | |
1461 | return -EINVAL; | |
1462 | ||
1463 | down_write(&configfs_rename_sem); | |
1464 | parent = item->parent->dentry; | |
1465 | ||
1b1dcc1b | 1466 | mutex_lock(&parent->d_inode->i_mutex); |
7063fbf2 JB |
1467 | |
1468 | new_dentry = lookup_one_len(new_name, parent, strlen(new_name)); | |
1469 | if (!IS_ERR(new_dentry)) { | |
e7515d06 | 1470 | if (!new_dentry->d_inode) { |
7063fbf2 JB |
1471 | error = config_item_set_name(item, "%s", new_name); |
1472 | if (!error) { | |
1473 | d_add(new_dentry, NULL); | |
1474 | d_move(item->dentry, new_dentry); | |
1475 | } | |
1476 | else | |
1477 | d_delete(new_dentry); | |
1478 | } else | |
1479 | error = -EEXIST; | |
1480 | dput(new_dentry); | |
1481 | } | |
1b1dcc1b | 1482 | mutex_unlock(&parent->d_inode->i_mutex); |
7063fbf2 JB |
1483 | up_write(&configfs_rename_sem); |
1484 | ||
1485 | return error; | |
1486 | } | |
1487 | #endif | |
1488 | ||
1489 | static int configfs_dir_open(struct inode *inode, struct file *file) | |
1490 | { | |
867fa491 | 1491 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 | 1492 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
2a109f2a | 1493 | int err; |
7063fbf2 | 1494 | |
1b1dcc1b | 1495 | mutex_lock(&dentry->d_inode->i_mutex); |
2a109f2a LR |
1496 | /* |
1497 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
1498 | * being attached | |
1499 | */ | |
1500 | err = -ENOENT; | |
1501 | if (configfs_dirent_is_ready(parent_sd)) { | |
420118ca | 1502 | file->private_data = configfs_new_dirent(parent_sd, NULL, 0); |
2a109f2a LR |
1503 | if (IS_ERR(file->private_data)) |
1504 | err = PTR_ERR(file->private_data); | |
1505 | else | |
1506 | err = 0; | |
1507 | } | |
1b1dcc1b | 1508 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 | 1509 | |
2a109f2a | 1510 | return err; |
7063fbf2 JB |
1511 | } |
1512 | ||
1513 | static int configfs_dir_close(struct inode *inode, struct file *file) | |
1514 | { | |
867fa491 | 1515 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 JB |
1516 | struct configfs_dirent * cursor = file->private_data; |
1517 | ||
1b1dcc1b | 1518 | mutex_lock(&dentry->d_inode->i_mutex); |
6f610764 | 1519 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 1520 | list_del_init(&cursor->s_sibling); |
6f610764 | 1521 | spin_unlock(&configfs_dirent_lock); |
1b1dcc1b | 1522 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1523 | |
1524 | release_configfs_dirent(cursor); | |
1525 | ||
1526 | return 0; | |
1527 | } | |
1528 | ||
1529 | /* Relationship between s_mode and the DT_xxx types */ | |
1530 | static inline unsigned char dt_type(struct configfs_dirent *sd) | |
1531 | { | |
1532 | return (sd->s_mode >> 12) & 15; | |
1533 | } | |
1534 | ||
1535 | static int configfs_readdir(struct file * filp, void * dirent, filldir_t filldir) | |
1536 | { | |
867fa491 | 1537 | struct dentry *dentry = filp->f_path.dentry; |
b7c177fc | 1538 | struct super_block *sb = dentry->d_sb; |
7063fbf2 JB |
1539 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
1540 | struct configfs_dirent *cursor = filp->private_data; | |
1541 | struct list_head *p, *q = &cursor->s_sibling; | |
24307aa1 | 1542 | ino_t ino = 0; |
7063fbf2 JB |
1543 | int i = filp->f_pos; |
1544 | ||
1545 | switch (i) { | |
1546 | case 0: | |
1547 | ino = dentry->d_inode->i_ino; | |
1548 | if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) | |
1549 | break; | |
1550 | filp->f_pos++; | |
1551 | i++; | |
1552 | /* fallthrough */ | |
1553 | case 1: | |
1554 | ino = parent_ino(dentry); | |
1555 | if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) | |
1556 | break; | |
1557 | filp->f_pos++; | |
1558 | i++; | |
1559 | /* fallthrough */ | |
1560 | default: | |
1561 | if (filp->f_pos == 2) { | |
6f610764 | 1562 | spin_lock(&configfs_dirent_lock); |
f116629d | 1563 | list_move(q, &parent_sd->s_children); |
6f610764 | 1564 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
1565 | } |
1566 | for (p=q->next; p!= &parent_sd->s_children; p=p->next) { | |
1567 | struct configfs_dirent *next; | |
1568 | const char * name; | |
1569 | int len; | |
24307aa1 | 1570 | struct inode *inode = NULL; |
7063fbf2 JB |
1571 | |
1572 | next = list_entry(p, struct configfs_dirent, | |
1573 | s_sibling); | |
1574 | if (!next->s_element) | |
1575 | continue; | |
1576 | ||
1577 | name = configfs_get_name(next); | |
1578 | len = strlen(name); | |
24307aa1 JB |
1579 | |
1580 | /* | |
1581 | * We'll have a dentry and an inode for | |
1582 | * PINNED items and for open attribute | |
1583 | * files. We lock here to prevent a race | |
1584 | * with configfs_d_iput() clearing | |
1585 | * s_dentry before calling iput(). | |
1586 | * | |
1587 | * Why do we go to the trouble? If | |
1588 | * someone has an attribute file open, | |
1589 | * the inode number should match until | |
1590 | * they close it. Beyond that, we don't | |
1591 | * care. | |
1592 | */ | |
1593 | spin_lock(&configfs_dirent_lock); | |
1594 | dentry = next->s_dentry; | |
1595 | if (dentry) | |
1596 | inode = dentry->d_inode; | |
1597 | if (inode) | |
1598 | ino = inode->i_ino; | |
1599 | spin_unlock(&configfs_dirent_lock); | |
1600 | if (!inode) | |
b7c177fc | 1601 | ino = iunique(sb, 2); |
7063fbf2 JB |
1602 | |
1603 | if (filldir(dirent, name, len, filp->f_pos, ino, | |
1604 | dt_type(next)) < 0) | |
1605 | return 0; | |
1606 | ||
6f610764 | 1607 | spin_lock(&configfs_dirent_lock); |
f116629d | 1608 | list_move(q, p); |
6f610764 | 1609 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
1610 | p = q; |
1611 | filp->f_pos++; | |
1612 | } | |
1613 | } | |
1614 | return 0; | |
1615 | } | |
1616 | ||
965c8e59 | 1617 | static loff_t configfs_dir_lseek(struct file *file, loff_t offset, int whence) |
7063fbf2 | 1618 | { |
867fa491 | 1619 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 | 1620 | |
1b1dcc1b | 1621 | mutex_lock(&dentry->d_inode->i_mutex); |
965c8e59 | 1622 | switch (whence) { |
7063fbf2 JB |
1623 | case 1: |
1624 | offset += file->f_pos; | |
1625 | case 0: | |
1626 | if (offset >= 0) | |
1627 | break; | |
1628 | default: | |
867fa491 | 1629 | mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); |
7063fbf2 JB |
1630 | return -EINVAL; |
1631 | } | |
1632 | if (offset != file->f_pos) { | |
1633 | file->f_pos = offset; | |
1634 | if (file->f_pos >= 2) { | |
1635 | struct configfs_dirent *sd = dentry->d_fsdata; | |
1636 | struct configfs_dirent *cursor = file->private_data; | |
1637 | struct list_head *p; | |
1638 | loff_t n = file->f_pos - 2; | |
1639 | ||
6f610764 | 1640 | spin_lock(&configfs_dirent_lock); |
7063fbf2 JB |
1641 | list_del(&cursor->s_sibling); |
1642 | p = sd->s_children.next; | |
1643 | while (n && p != &sd->s_children) { | |
1644 | struct configfs_dirent *next; | |
1645 | next = list_entry(p, struct configfs_dirent, | |
1646 | s_sibling); | |
1647 | if (next->s_element) | |
1648 | n--; | |
1649 | p = p->next; | |
1650 | } | |
1651 | list_add_tail(&cursor->s_sibling, p); | |
6f610764 | 1652 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
1653 | } |
1654 | } | |
1b1dcc1b | 1655 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1656 | return offset; |
1657 | } | |
1658 | ||
4b6f5d20 | 1659 | const struct file_operations configfs_dir_operations = { |
7063fbf2 JB |
1660 | .open = configfs_dir_open, |
1661 | .release = configfs_dir_close, | |
1662 | .llseek = configfs_dir_lseek, | |
1663 | .read = generic_read_dir, | |
1664 | .readdir = configfs_readdir, | |
1665 | }; | |
1666 | ||
1667 | int configfs_register_subsystem(struct configfs_subsystem *subsys) | |
1668 | { | |
1669 | int err; | |
1670 | struct config_group *group = &subsys->su_group; | |
1671 | struct qstr name; | |
1672 | struct dentry *dentry; | |
b7c177fc | 1673 | struct dentry *root; |
7063fbf2 JB |
1674 | struct configfs_dirent *sd; |
1675 | ||
2a152ad3 AV |
1676 | root = configfs_pin_fs(); |
1677 | if (IS_ERR(root)) | |
1678 | return PTR_ERR(root); | |
7063fbf2 JB |
1679 | |
1680 | if (!group->cg_item.ci_name) | |
1681 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
1682 | ||
b7c177fc | 1683 | sd = root->d_fsdata; |
7063fbf2 JB |
1684 | link_group(to_config_group(sd->s_element), group); |
1685 | ||
b7c177fc | 1686 | mutex_lock_nested(&root->d_inode->i_mutex, I_MUTEX_PARENT); |
7063fbf2 JB |
1687 | |
1688 | name.name = group->cg_item.ci_name; | |
1689 | name.len = strlen(name.name); | |
1690 | name.hash = full_name_hash(name.name, name.len); | |
1691 | ||
1692 | err = -ENOMEM; | |
b7c177fc | 1693 | dentry = d_alloc(root, &name); |
afdf04ea JB |
1694 | if (dentry) { |
1695 | d_add(dentry, NULL); | |
7063fbf2 | 1696 | |
afdf04ea JB |
1697 | err = configfs_attach_group(sd->s_element, &group->cg_item, |
1698 | dentry); | |
1699 | if (err) { | |
df7f9967 JB |
1700 | BUG_ON(dentry->d_inode); |
1701 | d_drop(dentry); | |
afdf04ea | 1702 | dput(dentry); |
2a109f2a LR |
1703 | } else { |
1704 | spin_lock(&configfs_dirent_lock); | |
1705 | configfs_dir_set_ready(dentry->d_fsdata); | |
1706 | spin_unlock(&configfs_dirent_lock); | |
afdf04ea JB |
1707 | } |
1708 | } | |
7063fbf2 | 1709 | |
b7c177fc | 1710 | mutex_unlock(&root->d_inode->i_mutex); |
7063fbf2 | 1711 | |
afdf04ea JB |
1712 | if (err) { |
1713 | unlink_group(group); | |
1714 | configfs_release_fs(); | |
7063fbf2 JB |
1715 | } |
1716 | ||
1717 | return err; | |
1718 | } | |
1719 | ||
1720 | void configfs_unregister_subsystem(struct configfs_subsystem *subsys) | |
1721 | { | |
1722 | struct config_group *group = &subsys->su_group; | |
1723 | struct dentry *dentry = group->cg_item.ci_dentry; | |
b7c177fc | 1724 | struct dentry *root = dentry->d_sb->s_root; |
7063fbf2 | 1725 | |
b7c177fc | 1726 | if (dentry->d_parent != root) { |
7063fbf2 JB |
1727 | printk(KERN_ERR "configfs: Tried to unregister non-subsystem!\n"); |
1728 | return; | |
1729 | } | |
1730 | ||
b7c177fc | 1731 | mutex_lock_nested(&root->d_inode->i_mutex, |
55ed1602 MF |
1732 | I_MUTEX_PARENT); |
1733 | mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); | |
9a73d78c | 1734 | mutex_lock(&configfs_symlink_mutex); |
b3e76af8 | 1735 | spin_lock(&configfs_dirent_lock); |
6d8344ba | 1736 | if (configfs_detach_prep(dentry, NULL)) { |
7063fbf2 JB |
1737 | printk(KERN_ERR "configfs: Tried to unregister non-empty subsystem!\n"); |
1738 | } | |
b3e76af8 | 1739 | spin_unlock(&configfs_dirent_lock); |
9a73d78c | 1740 | mutex_unlock(&configfs_symlink_mutex); |
7063fbf2 JB |
1741 | configfs_detach_group(&group->cg_item); |
1742 | dentry->d_inode->i_flags |= S_DEAD; | |
d83c49f3 | 1743 | dont_mount(dentry); |
1b1dcc1b | 1744 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1745 | |
1746 | d_delete(dentry); | |
1747 | ||
b7c177fc | 1748 | mutex_unlock(&root->d_inode->i_mutex); |
7063fbf2 JB |
1749 | |
1750 | dput(dentry); | |
1751 | ||
1752 | unlink_group(group); | |
1753 | configfs_release_fs(); | |
1754 | } | |
1755 | ||
1756 | EXPORT_SYMBOL(configfs_register_subsystem); | |
1757 | EXPORT_SYMBOL(configfs_unregister_subsystem); |