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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); | |
7a4ca203 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 | ||
78 | /* | |
79 | * We _must_ delete our dentries on last dput, as the chain-to-parent | |
80 | * behavior is required to clear the parents of default_groups. | |
81 | */ | |
fe15ce44 | 82 | static int configfs_d_delete(const struct dentry *dentry) |
7063fbf2 JB |
83 | { |
84 | return 1; | |
85 | } | |
86 | ||
d463a0c4 | 87 | const struct dentry_operations configfs_dentry_ops = { |
7063fbf2 JB |
88 | .d_iput = configfs_d_iput, |
89 | /* simple_delete_dentry() isn't exported */ | |
90 | .d_delete = configfs_d_delete, | |
91 | }; | |
92 | ||
e74cc06d LR |
93 | #ifdef CONFIG_LOCKDEP |
94 | ||
95 | /* | |
96 | * Helpers to make lockdep happy with our recursive locking of default groups' | |
97 | * inodes (see configfs_attach_group() and configfs_detach_group()). | |
98 | * We put default groups i_mutexes in separate classes according to their depth | |
99 | * from the youngest non-default group ancestor. | |
100 | * | |
101 | * For a non-default group A having default groups A/B, A/C, and A/C/D, default | |
102 | * groups A/B and A/C will have their inode's mutex in class | |
103 | * default_group_class[0], and default group A/C/D will be in | |
104 | * default_group_class[1]. | |
105 | * | |
106 | * The lock classes are declared and assigned in inode.c, according to the | |
107 | * s_depth value. | |
108 | * The s_depth value is initialized to -1, adjusted to >= 0 when attaching | |
109 | * default groups, and reset to -1 when all default groups are attached. During | |
110 | * attachment, if configfs_create() sees s_depth > 0, the lock class of the new | |
111 | * inode's mutex is set to default_group_class[s_depth - 1]. | |
112 | */ | |
113 | ||
114 | static void configfs_init_dirent_depth(struct configfs_dirent *sd) | |
115 | { | |
116 | sd->s_depth = -1; | |
117 | } | |
118 | ||
119 | static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd, | |
120 | struct configfs_dirent *sd) | |
121 | { | |
122 | int parent_depth = parent_sd->s_depth; | |
123 | ||
124 | if (parent_depth >= 0) | |
125 | sd->s_depth = parent_depth + 1; | |
126 | } | |
127 | ||
128 | static void | |
129 | configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd) | |
130 | { | |
131 | /* | |
132 | * item's i_mutex class is already setup, so s_depth is now only | |
133 | * used to set new sub-directories s_depth, which is always done | |
134 | * with item's i_mutex locked. | |
135 | */ | |
136 | /* | |
137 | * sd->s_depth == -1 iff we are a non default group. | |
138 | * else (we are a default group) sd->s_depth > 0 (see | |
139 | * create_dir()). | |
140 | */ | |
141 | if (sd->s_depth == -1) | |
142 | /* | |
143 | * We are a non default group and we are going to create | |
144 | * default groups. | |
145 | */ | |
146 | sd->s_depth = 0; | |
147 | } | |
148 | ||
149 | static void | |
150 | configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd) | |
151 | { | |
152 | /* We will not create default groups anymore. */ | |
153 | sd->s_depth = -1; | |
154 | } | |
155 | ||
156 | #else /* CONFIG_LOCKDEP */ | |
157 | ||
158 | static void configfs_init_dirent_depth(struct configfs_dirent *sd) | |
159 | { | |
160 | } | |
161 | ||
162 | static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd, | |
163 | struct configfs_dirent *sd) | |
164 | { | |
165 | } | |
166 | ||
167 | static void | |
168 | configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd) | |
169 | { | |
170 | } | |
171 | ||
172 | static void | |
173 | configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd) | |
174 | { | |
175 | } | |
176 | ||
177 | #endif /* CONFIG_LOCKDEP */ | |
178 | ||
7063fbf2 JB |
179 | /* |
180 | * Allocates a new configfs_dirent and links it to the parent configfs_dirent | |
181 | */ | |
420118ca LR |
182 | static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *parent_sd, |
183 | void *element, int type) | |
7063fbf2 JB |
184 | { |
185 | struct configfs_dirent * sd; | |
186 | ||
c3762229 | 187 | sd = kmem_cache_zalloc(configfs_dir_cachep, GFP_KERNEL); |
7063fbf2 | 188 | if (!sd) |
107ed40b | 189 | return ERR_PTR(-ENOMEM); |
7063fbf2 | 190 | |
7063fbf2 JB |
191 | atomic_set(&sd->s_count, 1); |
192 | INIT_LIST_HEAD(&sd->s_links); | |
193 | INIT_LIST_HEAD(&sd->s_children); | |
7063fbf2 | 194 | sd->s_element = element; |
420118ca | 195 | sd->s_type = type; |
e74cc06d | 196 | configfs_init_dirent_depth(sd); |
6f610764 | 197 | spin_lock(&configfs_dirent_lock); |
b3e76af8 LR |
198 | if (parent_sd->s_type & CONFIGFS_USET_DROPPING) { |
199 | spin_unlock(&configfs_dirent_lock); | |
200 | kmem_cache_free(configfs_dir_cachep, sd); | |
201 | return ERR_PTR(-ENOENT); | |
202 | } | |
6f610764 LR |
203 | list_add(&sd->s_sibling, &parent_sd->s_children); |
204 | spin_unlock(&configfs_dirent_lock); | |
7063fbf2 JB |
205 | |
206 | return sd; | |
207 | } | |
208 | ||
b4c98f62 JB |
209 | /* |
210 | * | |
211 | * Return -EEXIST if there is already a configfs element with the same | |
212 | * name for the same parent. | |
213 | * | |
214 | * called with parent inode's i_mutex held | |
215 | */ | |
58d206c2 AB |
216 | static int configfs_dirent_exists(struct configfs_dirent *parent_sd, |
217 | const unsigned char *new) | |
b4c98f62 JB |
218 | { |
219 | struct configfs_dirent * sd; | |
220 | ||
221 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
222 | if (sd->s_element) { | |
223 | const unsigned char *existing = configfs_get_name(sd); | |
224 | if (strcmp(existing, new)) | |
225 | continue; | |
226 | else | |
227 | return -EEXIST; | |
228 | } | |
229 | } | |
230 | ||
231 | return 0; | |
232 | } | |
233 | ||
234 | ||
7063fbf2 JB |
235 | int configfs_make_dirent(struct configfs_dirent * parent_sd, |
236 | struct dentry * dentry, void * element, | |
237 | umode_t mode, int type) | |
238 | { | |
239 | struct configfs_dirent * sd; | |
240 | ||
420118ca | 241 | sd = configfs_new_dirent(parent_sd, element, type); |
107ed40b LR |
242 | if (IS_ERR(sd)) |
243 | return PTR_ERR(sd); | |
7063fbf2 JB |
244 | |
245 | sd->s_mode = mode; | |
7063fbf2 | 246 | sd->s_dentry = dentry; |
fbc8d4c0 | 247 | if (dentry) |
7063fbf2 | 248 | dentry->d_fsdata = configfs_get(sd); |
7063fbf2 JB |
249 | |
250 | return 0; | |
251 | } | |
252 | ||
253 | static int init_dir(struct inode * inode) | |
254 | { | |
255 | inode->i_op = &configfs_dir_inode_operations; | |
256 | inode->i_fop = &configfs_dir_operations; | |
257 | ||
258 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |
d8c76e6f | 259 | inc_nlink(inode); |
7063fbf2 JB |
260 | return 0; |
261 | } | |
262 | ||
ce8d2cdf | 263 | static int configfs_init_file(struct inode * inode) |
7063fbf2 JB |
264 | { |
265 | inode->i_size = PAGE_SIZE; | |
266 | inode->i_fop = &configfs_file_operations; | |
267 | return 0; | |
268 | } | |
269 | ||
270 | static int init_symlink(struct inode * inode) | |
271 | { | |
272 | inode->i_op = &configfs_symlink_inode_operations; | |
273 | return 0; | |
274 | } | |
275 | ||
0dd6c08a | 276 | static int create_dir(struct config_item *k, struct dentry *d) |
7063fbf2 JB |
277 | { |
278 | int error; | |
279 | umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; | |
0dd6c08a AV |
280 | struct dentry *p = d->d_parent; |
281 | ||
282 | BUG_ON(!k); | |
7063fbf2 | 283 | |
b4c98f62 JB |
284 | error = configfs_dirent_exists(p->d_fsdata, d->d_name.name); |
285 | if (!error) | |
286 | error = configfs_make_dirent(p->d_fsdata, d, k, mode, | |
2a109f2a | 287 | CONFIGFS_DIR | CONFIGFS_USET_CREATING); |
7063fbf2 | 288 | if (!error) { |
e74cc06d | 289 | configfs_set_dir_dirent_depth(p->d_fsdata, d->d_fsdata); |
3d0f89bb | 290 | error = configfs_create(d, mode, init_dir); |
7063fbf2 | 291 | if (!error) { |
d8c76e6f | 292 | inc_nlink(p->d_inode); |
3d0f89bb JB |
293 | } else { |
294 | struct configfs_dirent *sd = d->d_fsdata; | |
295 | if (sd) { | |
6f610764 | 296 | spin_lock(&configfs_dirent_lock); |
3d0f89bb | 297 | list_del_init(&sd->s_sibling); |
6f610764 | 298 | spin_unlock(&configfs_dirent_lock); |
3d0f89bb JB |
299 | configfs_put(sd); |
300 | } | |
7063fbf2 JB |
301 | } |
302 | } | |
303 | return error; | |
304 | } | |
305 | ||
306 | ||
307 | /** | |
308 | * configfs_create_dir - create a directory for an config_item. | |
309 | * @item: config_itemwe're creating directory for. | |
310 | * @dentry: config_item's dentry. | |
2a109f2a LR |
311 | * |
312 | * Note: user-created entries won't be allowed under this new directory | |
313 | * until it is validated by configfs_dir_set_ready() | |
7063fbf2 JB |
314 | */ |
315 | ||
316 | static int configfs_create_dir(struct config_item * item, struct dentry *dentry) | |
317 | { | |
0dd6c08a | 318 | int error = create_dir(item, dentry); |
7063fbf2 JB |
319 | if (!error) |
320 | item->ci_dentry = dentry; | |
321 | return error; | |
322 | } | |
323 | ||
2a109f2a LR |
324 | /* |
325 | * Allow userspace to create new entries under a new directory created with | |
326 | * configfs_create_dir(), and under all of its chidlren directories recursively. | |
327 | * @sd configfs_dirent of the new directory to validate | |
328 | * | |
329 | * Caller must hold configfs_dirent_lock. | |
330 | */ | |
331 | static void configfs_dir_set_ready(struct configfs_dirent *sd) | |
332 | { | |
333 | struct configfs_dirent *child_sd; | |
334 | ||
335 | sd->s_type &= ~CONFIGFS_USET_CREATING; | |
336 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) | |
337 | if (child_sd->s_type & CONFIGFS_USET_CREATING) | |
338 | configfs_dir_set_ready(child_sd); | |
339 | } | |
340 | ||
341 | /* | |
342 | * Check that a directory does not belong to a directory hierarchy being | |
343 | * attached and not validated yet. | |
344 | * @sd configfs_dirent of the directory to check | |
345 | * | |
346 | * @return non-zero iff the directory was validated | |
347 | * | |
348 | * Note: takes configfs_dirent_lock, so the result may change from false to true | |
349 | * in two consecutive calls, but never from true to false. | |
350 | */ | |
351 | int configfs_dirent_is_ready(struct configfs_dirent *sd) | |
352 | { | |
353 | int ret; | |
354 | ||
355 | spin_lock(&configfs_dirent_lock); | |
356 | ret = !(sd->s_type & CONFIGFS_USET_CREATING); | |
357 | spin_unlock(&configfs_dirent_lock); | |
358 | ||
359 | return ret; | |
360 | } | |
361 | ||
7063fbf2 JB |
362 | int configfs_create_link(struct configfs_symlink *sl, |
363 | struct dentry *parent, | |
364 | struct dentry *dentry) | |
365 | { | |
366 | int err = 0; | |
367 | umode_t mode = S_IFLNK | S_IRWXUGO; | |
368 | ||
3d0f89bb JB |
369 | err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode, |
370 | CONFIGFS_ITEM_LINK); | |
7063fbf2 | 371 | if (!err) { |
3d0f89bb | 372 | err = configfs_create(dentry, mode, init_symlink); |
fbc8d4c0 | 373 | if (err) { |
3d0f89bb JB |
374 | struct configfs_dirent *sd = dentry->d_fsdata; |
375 | if (sd) { | |
6f610764 | 376 | spin_lock(&configfs_dirent_lock); |
3d0f89bb | 377 | list_del_init(&sd->s_sibling); |
6f610764 | 378 | spin_unlock(&configfs_dirent_lock); |
3d0f89bb JB |
379 | configfs_put(sd); |
380 | } | |
381 | } | |
7063fbf2 JB |
382 | } |
383 | return err; | |
384 | } | |
385 | ||
386 | static void remove_dir(struct dentry * d) | |
387 | { | |
388 | struct dentry * parent = dget(d->d_parent); | |
389 | struct configfs_dirent * sd; | |
390 | ||
391 | sd = d->d_fsdata; | |
6f610764 | 392 | spin_lock(&configfs_dirent_lock); |
e7515d06 | 393 | list_del_init(&sd->s_sibling); |
6f610764 | 394 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
395 | configfs_put(sd); |
396 | if (d->d_inode) | |
397 | simple_rmdir(parent->d_inode,d); | |
398 | ||
b7ab39f6 | 399 | pr_debug(" o %s removing done (%d)\n",d->d_name.name, d->d_count); |
7063fbf2 JB |
400 | |
401 | dput(parent); | |
402 | } | |
403 | ||
404 | /** | |
405 | * configfs_remove_dir - remove an config_item's directory. | |
406 | * @item: config_item we're removing. | |
407 | * | |
408 | * The only thing special about this is that we remove any files in | |
409 | * the directory before we remove the directory, and we've inlined | |
410 | * what used to be configfs_rmdir() below, instead of calling separately. | |
2e2ce171 LR |
411 | * |
412 | * Caller holds the mutex of the item's inode | |
7063fbf2 JB |
413 | */ |
414 | ||
415 | static void configfs_remove_dir(struct config_item * item) | |
416 | { | |
417 | struct dentry * dentry = dget(item->ci_dentry); | |
418 | ||
419 | if (!dentry) | |
420 | return; | |
421 | ||
422 | remove_dir(dentry); | |
423 | /** | |
424 | * Drop reference from dget() on entrance. | |
425 | */ | |
426 | dput(dentry); | |
427 | } | |
428 | ||
429 | ||
430 | /* attaches attribute's configfs_dirent to the dentry corresponding to the | |
431 | * attribute file | |
432 | */ | |
433 | static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry) | |
434 | { | |
435 | struct configfs_attribute * attr = sd->s_element; | |
436 | int error; | |
437 | ||
7a4ca203 | 438 | spin_lock(&configfs_dirent_lock); |
3d0f89bb JB |
439 | dentry->d_fsdata = configfs_get(sd); |
440 | sd->s_dentry = dentry; | |
7a4ca203 JB |
441 | spin_unlock(&configfs_dirent_lock); |
442 | ||
ce8d2cdf DH |
443 | error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG, |
444 | configfs_init_file); | |
3d0f89bb JB |
445 | if (error) { |
446 | configfs_put(sd); | |
7063fbf2 | 447 | return error; |
3d0f89bb | 448 | } |
7063fbf2 | 449 | |
7063fbf2 JB |
450 | d_rehash(dentry); |
451 | ||
452 | return 0; | |
453 | } | |
454 | ||
455 | static struct dentry * configfs_lookup(struct inode *dir, | |
456 | struct dentry *dentry, | |
00cd8dd3 | 457 | unsigned int flags) |
7063fbf2 JB |
458 | { |
459 | struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata; | |
460 | struct configfs_dirent * sd; | |
461 | int found = 0; | |
2a109f2a LR |
462 | int err; |
463 | ||
464 | /* | |
465 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
466 | * being attached | |
467 | * | |
468 | * This forbids userspace to read/write attributes of items which may | |
469 | * not complete their initialization, since the dentries of the | |
470 | * attributes won't be instantiated. | |
471 | */ | |
472 | err = -ENOENT; | |
473 | if (!configfs_dirent_is_ready(parent_sd)) | |
474 | goto out; | |
7063fbf2 JB |
475 | |
476 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
477 | if (sd->s_type & CONFIGFS_NOT_PINNED) { | |
478 | const unsigned char * name = configfs_get_name(sd); | |
479 | ||
480 | if (strcmp(name, dentry->d_name.name)) | |
481 | continue; | |
482 | ||
483 | found = 1; | |
484 | err = configfs_attach_attr(sd, dentry); | |
485 | break; | |
486 | } | |
487 | } | |
488 | ||
489 | if (!found) { | |
490 | /* | |
491 | * If it doesn't exist and it isn't a NOT_PINNED item, | |
492 | * it must be negative. | |
493 | */ | |
fbc8d4c0 NP |
494 | if (dentry->d_name.len > NAME_MAX) |
495 | return ERR_PTR(-ENAMETOOLONG); | |
fbc8d4c0 NP |
496 | d_add(dentry, NULL); |
497 | return NULL; | |
7063fbf2 JB |
498 | } |
499 | ||
2a109f2a | 500 | out: |
7063fbf2 JB |
501 | return ERR_PTR(err); |
502 | } | |
503 | ||
504 | /* | |
505 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are | |
b3e76af8 LR |
506 | * attributes and are removed by rmdir(). We recurse, setting |
507 | * CONFIGFS_USET_DROPPING on all children that are candidates for | |
508 | * default detach. | |
509 | * If there is an error, the caller will reset the flags via | |
510 | * configfs_detach_rollback(). | |
7063fbf2 | 511 | */ |
6d8344ba | 512 | static int configfs_detach_prep(struct dentry *dentry, struct mutex **wait_mutex) |
7063fbf2 JB |
513 | { |
514 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
515 | struct configfs_dirent *sd; | |
516 | int ret; | |
517 | ||
4768e9b1 LR |
518 | /* Mark that we're trying to drop the group */ |
519 | parent_sd->s_type |= CONFIGFS_USET_DROPPING; | |
520 | ||
7063fbf2 JB |
521 | ret = -EBUSY; |
522 | if (!list_empty(&parent_sd->s_links)) | |
523 | goto out; | |
524 | ||
525 | ret = 0; | |
526 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
99cefda4 LR |
527 | if (!sd->s_element || |
528 | (sd->s_type & CONFIGFS_NOT_PINNED)) | |
7063fbf2 JB |
529 | continue; |
530 | if (sd->s_type & CONFIGFS_USET_DEFAULT) { | |
6d8344ba LR |
531 | /* Abort if racing with mkdir() */ |
532 | if (sd->s_type & CONFIGFS_USET_IN_MKDIR) { | |
533 | if (wait_mutex) | |
534 | *wait_mutex = &sd->s_dentry->d_inode->i_mutex; | |
535 | return -EAGAIN; | |
536 | } | |
7063fbf2 | 537 | |
631d1feb JB |
538 | /* |
539 | * Yup, recursive. If there's a problem, blame | |
540 | * deep nesting of default_groups | |
541 | */ | |
6d8344ba | 542 | ret = configfs_detach_prep(sd->s_dentry, wait_mutex); |
7063fbf2 | 543 | if (!ret) |
e7515d06 | 544 | continue; |
7063fbf2 JB |
545 | } else |
546 | ret = -ENOTEMPTY; | |
547 | ||
548 | break; | |
549 | } | |
550 | ||
551 | out: | |
552 | return ret; | |
553 | } | |
554 | ||
555 | /* | |
b3e76af8 | 556 | * Walk the tree, resetting CONFIGFS_USET_DROPPING wherever it was |
7063fbf2 JB |
557 | * set. |
558 | */ | |
559 | static void configfs_detach_rollback(struct dentry *dentry) | |
560 | { | |
561 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
562 | struct configfs_dirent *sd; | |
563 | ||
4768e9b1 LR |
564 | parent_sd->s_type &= ~CONFIGFS_USET_DROPPING; |
565 | ||
566 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) | |
567 | if (sd->s_type & CONFIGFS_USET_DEFAULT) | |
7063fbf2 | 568 | configfs_detach_rollback(sd->s_dentry); |
7063fbf2 JB |
569 | } |
570 | ||
571 | static void detach_attrs(struct config_item * item) | |
572 | { | |
573 | struct dentry * dentry = dget(item->ci_dentry); | |
574 | struct configfs_dirent * parent_sd; | |
575 | struct configfs_dirent * sd, * tmp; | |
576 | ||
577 | if (!dentry) | |
578 | return; | |
579 | ||
580 | pr_debug("configfs %s: dropping attrs for dir\n", | |
581 | dentry->d_name.name); | |
582 | ||
583 | parent_sd = dentry->d_fsdata; | |
584 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
585 | if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED)) | |
586 | continue; | |
6f610764 | 587 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 588 | list_del_init(&sd->s_sibling); |
6f610764 | 589 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
590 | configfs_drop_dentry(sd, dentry); |
591 | configfs_put(sd); | |
592 | } | |
593 | ||
594 | /** | |
595 | * Drop reference from dget() on entrance. | |
596 | */ | |
597 | dput(dentry); | |
598 | } | |
599 | ||
600 | static int populate_attrs(struct config_item *item) | |
601 | { | |
602 | struct config_item_type *t = item->ci_type; | |
603 | struct configfs_attribute *attr; | |
604 | int error = 0; | |
605 | int i; | |
606 | ||
607 | if (!t) | |
608 | return -EINVAL; | |
609 | if (t->ct_attrs) { | |
610 | for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) { | |
611 | if ((error = configfs_create_file(item, attr))) | |
612 | break; | |
613 | } | |
614 | } | |
615 | ||
616 | if (error) | |
617 | detach_attrs(item); | |
618 | ||
619 | return error; | |
620 | } | |
621 | ||
622 | static int configfs_attach_group(struct config_item *parent_item, | |
623 | struct config_item *item, | |
624 | struct dentry *dentry); | |
625 | static void configfs_detach_group(struct config_item *item); | |
626 | ||
627 | static void detach_groups(struct config_group *group) | |
628 | { | |
629 | struct dentry * dentry = dget(group->cg_item.ci_dentry); | |
630 | struct dentry *child; | |
631 | struct configfs_dirent *parent_sd; | |
632 | struct configfs_dirent *sd, *tmp; | |
633 | ||
634 | if (!dentry) | |
635 | return; | |
636 | ||
637 | parent_sd = dentry->d_fsdata; | |
638 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
639 | if (!sd->s_element || | |
640 | !(sd->s_type & CONFIGFS_USET_DEFAULT)) | |
641 | continue; | |
642 | ||
643 | child = sd->s_dentry; | |
644 | ||
b3e76af8 LR |
645 | mutex_lock(&child->d_inode->i_mutex); |
646 | ||
7063fbf2 JB |
647 | configfs_detach_group(sd->s_element); |
648 | child->d_inode->i_flags |= S_DEAD; | |
d83c49f3 | 649 | dont_mount(child); |
7063fbf2 | 650 | |
b3e76af8 | 651 | mutex_unlock(&child->d_inode->i_mutex); |
7063fbf2 JB |
652 | |
653 | d_delete(child); | |
654 | dput(child); | |
655 | } | |
656 | ||
657 | /** | |
658 | * Drop reference from dget() on entrance. | |
659 | */ | |
660 | dput(dentry); | |
661 | } | |
662 | ||
663 | /* | |
664 | * This fakes mkdir(2) on a default_groups[] entry. It | |
665 | * creates a dentry, attachs it, and then does fixup | |
666 | * on the sd->s_type. | |
667 | * | |
668 | * We could, perhaps, tweak our parent's ->mkdir for a minute and | |
669 | * try using vfs_mkdir. Just a thought. | |
670 | */ | |
671 | static int create_default_group(struct config_group *parent_group, | |
672 | struct config_group *group) | |
673 | { | |
674 | int ret; | |
675 | struct qstr name; | |
676 | struct configfs_dirent *sd; | |
677 | /* We trust the caller holds a reference to parent */ | |
678 | struct dentry *child, *parent = parent_group->cg_item.ci_dentry; | |
679 | ||
680 | if (!group->cg_item.ci_name) | |
681 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
682 | name.name = group->cg_item.ci_name; | |
683 | name.len = strlen(name.name); | |
684 | name.hash = full_name_hash(name.name, name.len); | |
685 | ||
686 | ret = -ENOMEM; | |
687 | child = d_alloc(parent, &name); | |
688 | if (child) { | |
689 | d_add(child, NULL); | |
690 | ||
691 | ret = configfs_attach_group(&parent_group->cg_item, | |
692 | &group->cg_item, child); | |
693 | if (!ret) { | |
694 | sd = child->d_fsdata; | |
695 | sd->s_type |= CONFIGFS_USET_DEFAULT; | |
696 | } else { | |
df7f9967 JB |
697 | BUG_ON(child->d_inode); |
698 | d_drop(child); | |
7063fbf2 JB |
699 | dput(child); |
700 | } | |
701 | } | |
702 | ||
703 | return ret; | |
704 | } | |
705 | ||
706 | static int populate_groups(struct config_group *group) | |
707 | { | |
708 | struct config_group *new_group; | |
7063fbf2 JB |
709 | int ret = 0; |
710 | int i; | |
711 | ||
cbca692c | 712 | if (group->default_groups) { |
7063fbf2 JB |
713 | for (i = 0; group->default_groups[i]; i++) { |
714 | new_group = group->default_groups[i]; | |
715 | ||
716 | ret = create_default_group(group, new_group); | |
2e2ce171 LR |
717 | if (ret) { |
718 | detach_groups(group); | |
7063fbf2 | 719 | break; |
2e2ce171 | 720 | } |
7063fbf2 | 721 | } |
7063fbf2 JB |
722 | } |
723 | ||
7063fbf2 JB |
724 | return ret; |
725 | } | |
726 | ||
727 | /* | |
728 | * All of link_obj/unlink_obj/link_group/unlink_group require that | |
e6bd07ae | 729 | * subsys->su_mutex is held. |
7063fbf2 JB |
730 | */ |
731 | ||
732 | static void unlink_obj(struct config_item *item) | |
733 | { | |
734 | struct config_group *group; | |
735 | ||
736 | group = item->ci_group; | |
737 | if (group) { | |
738 | list_del_init(&item->ci_entry); | |
739 | ||
740 | item->ci_group = NULL; | |
741 | item->ci_parent = NULL; | |
eed7a0db JB |
742 | |
743 | /* Drop the reference for ci_entry */ | |
7063fbf2 JB |
744 | config_item_put(item); |
745 | ||
eed7a0db | 746 | /* Drop the reference for ci_parent */ |
7063fbf2 JB |
747 | config_group_put(group); |
748 | } | |
749 | } | |
750 | ||
751 | static void link_obj(struct config_item *parent_item, struct config_item *item) | |
752 | { | |
eed7a0db JB |
753 | /* |
754 | * Parent seems redundant with group, but it makes certain | |
755 | * traversals much nicer. | |
756 | */ | |
7063fbf2 | 757 | item->ci_parent = parent_item; |
eed7a0db JB |
758 | |
759 | /* | |
760 | * We hold a reference on the parent for the child's ci_parent | |
761 | * link. | |
762 | */ | |
7063fbf2 JB |
763 | item->ci_group = config_group_get(to_config_group(parent_item)); |
764 | list_add_tail(&item->ci_entry, &item->ci_group->cg_children); | |
765 | ||
eed7a0db JB |
766 | /* |
767 | * We hold a reference on the child for ci_entry on the parent's | |
768 | * cg_children | |
769 | */ | |
7063fbf2 JB |
770 | config_item_get(item); |
771 | } | |
772 | ||
773 | static void unlink_group(struct config_group *group) | |
774 | { | |
775 | int i; | |
776 | struct config_group *new_group; | |
777 | ||
778 | if (group->default_groups) { | |
779 | for (i = 0; group->default_groups[i]; i++) { | |
780 | new_group = group->default_groups[i]; | |
781 | unlink_group(new_group); | |
782 | } | |
783 | } | |
784 | ||
785 | group->cg_subsys = NULL; | |
786 | unlink_obj(&group->cg_item); | |
787 | } | |
788 | ||
789 | static void link_group(struct config_group *parent_group, struct config_group *group) | |
790 | { | |
791 | int i; | |
792 | struct config_group *new_group; | |
793 | struct configfs_subsystem *subsys = NULL; /* gcc is a turd */ | |
794 | ||
795 | link_obj(&parent_group->cg_item, &group->cg_item); | |
796 | ||
797 | if (parent_group->cg_subsys) | |
798 | subsys = parent_group->cg_subsys; | |
799 | else if (configfs_is_root(&parent_group->cg_item)) | |
800 | subsys = to_configfs_subsystem(group); | |
801 | else | |
802 | BUG(); | |
803 | group->cg_subsys = subsys; | |
804 | ||
805 | if (group->default_groups) { | |
806 | for (i = 0; group->default_groups[i]; i++) { | |
807 | new_group = group->default_groups[i]; | |
808 | link_group(group, new_group); | |
809 | } | |
810 | } | |
811 | } | |
812 | ||
813 | /* | |
814 | * The goal is that configfs_attach_item() (and | |
815 | * configfs_attach_group()) can be called from either the VFS or this | |
816 | * module. That is, they assume that the items have been created, | |
817 | * the dentry allocated, and the dcache is all ready to go. | |
818 | * | |
819 | * If they fail, they must clean up after themselves as if they | |
820 | * had never been called. The caller (VFS or local function) will | |
821 | * handle cleaning up the dcache bits. | |
822 | * | |
823 | * configfs_detach_group() and configfs_detach_item() behave similarly on | |
824 | * the way out. They assume that the proper semaphores are held, they | |
825 | * clean up the configfs items, and they expect their callers will | |
826 | * handle the dcache bits. | |
827 | */ | |
828 | static int configfs_attach_item(struct config_item *parent_item, | |
829 | struct config_item *item, | |
830 | struct dentry *dentry) | |
831 | { | |
832 | int ret; | |
833 | ||
834 | ret = configfs_create_dir(item, dentry); | |
835 | if (!ret) { | |
836 | ret = populate_attrs(item); | |
837 | if (ret) { | |
2e2ce171 LR |
838 | /* |
839 | * We are going to remove an inode and its dentry but | |
840 | * the VFS may already have hit and used them. Thus, | |
841 | * we must lock them as rmdir() would. | |
842 | */ | |
843 | mutex_lock(&dentry->d_inode->i_mutex); | |
7063fbf2 | 844 | configfs_remove_dir(item); |
2e2ce171 | 845 | dentry->d_inode->i_flags |= S_DEAD; |
d83c49f3 | 846 | dont_mount(dentry); |
2e2ce171 | 847 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
848 | d_delete(dentry); |
849 | } | |
850 | } | |
851 | ||
852 | return ret; | |
853 | } | |
854 | ||
2e2ce171 | 855 | /* Caller holds the mutex of the item's inode */ |
7063fbf2 JB |
856 | static void configfs_detach_item(struct config_item *item) |
857 | { | |
858 | detach_attrs(item); | |
859 | configfs_remove_dir(item); | |
860 | } | |
861 | ||
862 | static int configfs_attach_group(struct config_item *parent_item, | |
863 | struct config_item *item, | |
864 | struct dentry *dentry) | |
865 | { | |
866 | int ret; | |
867 | struct configfs_dirent *sd; | |
868 | ||
869 | ret = configfs_attach_item(parent_item, item, dentry); | |
870 | if (!ret) { | |
871 | sd = dentry->d_fsdata; | |
872 | sd->s_type |= CONFIGFS_USET_DIR; | |
873 | ||
2e2ce171 LR |
874 | /* |
875 | * FYI, we're faking mkdir in populate_groups() | |
876 | * We must lock the group's inode to avoid races with the VFS | |
877 | * which can already hit the inode and try to add/remove entries | |
878 | * under it. | |
879 | * | |
880 | * We must also lock the inode to remove it safely in case of | |
881 | * error, as rmdir() would. | |
882 | */ | |
883 | mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); | |
e74cc06d | 884 | configfs_adjust_dir_dirent_depth_before_populate(sd); |
7063fbf2 JB |
885 | ret = populate_groups(to_config_group(item)); |
886 | if (ret) { | |
887 | configfs_detach_item(item); | |
2e2ce171 | 888 | dentry->d_inode->i_flags |= S_DEAD; |
d83c49f3 | 889 | dont_mount(dentry); |
7063fbf2 | 890 | } |
e74cc06d | 891 | configfs_adjust_dir_dirent_depth_after_populate(sd); |
2e2ce171 LR |
892 | mutex_unlock(&dentry->d_inode->i_mutex); |
893 | if (ret) | |
894 | d_delete(dentry); | |
7063fbf2 JB |
895 | } |
896 | ||
897 | return ret; | |
898 | } | |
899 | ||
2e2ce171 | 900 | /* Caller holds the mutex of the group's inode */ |
7063fbf2 JB |
901 | static void configfs_detach_group(struct config_item *item) |
902 | { | |
903 | detach_groups(to_config_group(item)); | |
904 | configfs_detach_item(item); | |
905 | } | |
906 | ||
299894cc JB |
907 | /* |
908 | * After the item has been detached from the filesystem view, we are | |
909 | * ready to tear it out of the hierarchy. Notify the client before | |
910 | * we do that so they can perform any cleanup that requires | |
911 | * navigating the hierarchy. A client does not need to provide this | |
912 | * callback. The subsystem semaphore MUST be held by the caller, and | |
913 | * references must be valid for both items. It also assumes the | |
914 | * caller has validated ci_type. | |
915 | */ | |
916 | static void client_disconnect_notify(struct config_item *parent_item, | |
917 | struct config_item *item) | |
918 | { | |
919 | struct config_item_type *type; | |
920 | ||
921 | type = parent_item->ci_type; | |
922 | BUG_ON(!type); | |
923 | ||
924 | if (type->ct_group_ops && type->ct_group_ops->disconnect_notify) | |
925 | type->ct_group_ops->disconnect_notify(to_config_group(parent_item), | |
926 | item); | |
927 | } | |
928 | ||
7063fbf2 JB |
929 | /* |
930 | * Drop the initial reference from make_item()/make_group() | |
931 | * This function assumes that reference is held on item | |
932 | * and that item holds a valid reference to the parent. Also, it | |
933 | * assumes the caller has validated ci_type. | |
934 | */ | |
935 | static void client_drop_item(struct config_item *parent_item, | |
936 | struct config_item *item) | |
937 | { | |
938 | struct config_item_type *type; | |
939 | ||
940 | type = parent_item->ci_type; | |
941 | BUG_ON(!type); | |
942 | ||
eed7a0db JB |
943 | /* |
944 | * If ->drop_item() exists, it is responsible for the | |
945 | * config_item_put(). | |
946 | */ | |
7063fbf2 JB |
947 | if (type->ct_group_ops && type->ct_group_ops->drop_item) |
948 | type->ct_group_ops->drop_item(to_config_group(parent_item), | |
299894cc | 949 | item); |
7063fbf2 JB |
950 | else |
951 | config_item_put(item); | |
952 | } | |
953 | ||
631d1feb JB |
954 | #ifdef DEBUG |
955 | static void configfs_dump_one(struct configfs_dirent *sd, int level) | |
956 | { | |
957 | printk(KERN_INFO "%*s\"%s\":\n", level, " ", configfs_get_name(sd)); | |
958 | ||
959 | #define type_print(_type) if (sd->s_type & _type) printk(KERN_INFO "%*s %s\n", level, " ", #_type); | |
960 | type_print(CONFIGFS_ROOT); | |
961 | type_print(CONFIGFS_DIR); | |
962 | type_print(CONFIGFS_ITEM_ATTR); | |
963 | type_print(CONFIGFS_ITEM_LINK); | |
964 | type_print(CONFIGFS_USET_DIR); | |
965 | type_print(CONFIGFS_USET_DEFAULT); | |
966 | type_print(CONFIGFS_USET_DROPPING); | |
967 | #undef type_print | |
968 | } | |
969 | ||
970 | static int configfs_dump(struct configfs_dirent *sd, int level) | |
971 | { | |
972 | struct configfs_dirent *child_sd; | |
973 | int ret = 0; | |
974 | ||
975 | configfs_dump_one(sd, level); | |
976 | ||
977 | if (!(sd->s_type & (CONFIGFS_DIR|CONFIGFS_ROOT))) | |
978 | return 0; | |
979 | ||
980 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) { | |
981 | ret = configfs_dump(child_sd, level + 2); | |
982 | if (ret) | |
983 | break; | |
984 | } | |
985 | ||
986 | return ret; | |
987 | } | |
988 | #endif | |
989 | ||
990 | ||
991 | /* | |
992 | * configfs_depend_item() and configfs_undepend_item() | |
993 | * | |
994 | * WARNING: Do not call these from a configfs callback! | |
995 | * | |
996 | * This describes these functions and their helpers. | |
997 | * | |
998 | * Allow another kernel system to depend on a config_item. If this | |
25985edc | 999 | * happens, the item cannot go away until the dependent can live without |
631d1feb JB |
1000 | * it. The idea is to give client modules as simple an interface as |
1001 | * possible. When a system asks them to depend on an item, they just | |
1002 | * call configfs_depend_item(). If the item is live and the client | |
1003 | * driver is in good shape, we'll happily do the work for them. | |
1004 | * | |
1005 | * Why is the locking complex? Because configfs uses the VFS to handle | |
1006 | * all locking, but this function is called outside the normal | |
1007 | * VFS->configfs path. So it must take VFS locks to prevent the | |
1008 | * VFS->configfs stuff (configfs_mkdir(), configfs_rmdir(), etc). This is | |
1009 | * why you can't call these functions underneath configfs callbacks. | |
1010 | * | |
1011 | * Note, btw, that this can be called at *any* time, even when a configfs | |
1012 | * subsystem isn't registered, or when configfs is loading or unloading. | |
1013 | * Just like configfs_register_subsystem(). So we take the same | |
420118ca LR |
1014 | * precautions. We pin the filesystem. We lock configfs_dirent_lock. |
1015 | * If we can find the target item in the | |
631d1feb | 1016 | * configfs tree, it must be part of the subsystem tree as well, so we |
420118ca LR |
1017 | * do not need the subsystem semaphore. Holding configfs_dirent_lock helps |
1018 | * locking out mkdir() and rmdir(), who might be racing us. | |
631d1feb JB |
1019 | */ |
1020 | ||
1021 | /* | |
1022 | * configfs_depend_prep() | |
1023 | * | |
1024 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are | |
1025 | * attributes. This is similar but not the same to configfs_detach_prep(). | |
1026 | * Note that configfs_detach_prep() expects the parent to be locked when it | |
1027 | * is called, but we lock the parent *inside* configfs_depend_prep(). We | |
1028 | * do that so we can unlock it if we find nothing. | |
1029 | * | |
1030 | * Here we do a depth-first search of the dentry hierarchy looking for | |
420118ca LR |
1031 | * our object. |
1032 | * We deliberately ignore items tagged as dropping since they are virtually | |
1033 | * dead, as well as items in the middle of attachment since they virtually | |
1034 | * do not exist yet. This completes the locking out of racing mkdir() and | |
1035 | * rmdir(). | |
1036 | * Note: subdirectories in the middle of attachment start with s_type = | |
1037 | * CONFIGFS_DIR|CONFIGFS_USET_CREATING set by create_dir(). When | |
1038 | * CONFIGFS_USET_CREATING is set, we ignore the item. The actual set of | |
1039 | * s_type is in configfs_new_dirent(), which has configfs_dirent_lock. | |
631d1feb | 1040 | * |
420118ca | 1041 | * If the target is not found, -ENOENT is bubbled up. |
631d1feb JB |
1042 | * |
1043 | * This adds a requirement that all config_items be unique! | |
1044 | * | |
420118ca | 1045 | * This is recursive. There isn't |
631d1feb JB |
1046 | * much on the stack, though, so folks that need this function - be careful |
1047 | * about your stack! Patches will be accepted to make it iterative. | |
1048 | */ | |
1049 | static int configfs_depend_prep(struct dentry *origin, | |
1050 | struct config_item *target) | |
1051 | { | |
49deb4bc | 1052 | struct configfs_dirent *child_sd, *sd; |
631d1feb JB |
1053 | int ret = 0; |
1054 | ||
49deb4bc WY |
1055 | BUG_ON(!origin || !origin->d_fsdata); |
1056 | sd = origin->d_fsdata; | |
631d1feb | 1057 | |
631d1feb JB |
1058 | if (sd->s_element == target) /* Boo-yah */ |
1059 | goto out; | |
1060 | ||
1061 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) { | |
420118ca LR |
1062 | if ((child_sd->s_type & CONFIGFS_DIR) && |
1063 | !(child_sd->s_type & CONFIGFS_USET_DROPPING) && | |
1064 | !(child_sd->s_type & CONFIGFS_USET_CREATING)) { | |
631d1feb JB |
1065 | ret = configfs_depend_prep(child_sd->s_dentry, |
1066 | target); | |
1067 | if (!ret) | |
1068 | goto out; /* Child path boo-yah */ | |
1069 | } | |
1070 | } | |
1071 | ||
1072 | /* We looped all our children and didn't find target */ | |
631d1feb JB |
1073 | ret = -ENOENT; |
1074 | ||
1075 | out: | |
1076 | return ret; | |
1077 | } | |
1078 | ||
631d1feb JB |
1079 | int configfs_depend_item(struct configfs_subsystem *subsys, |
1080 | struct config_item *target) | |
1081 | { | |
1082 | int ret; | |
1083 | struct configfs_dirent *p, *root_sd, *subsys_sd = NULL; | |
1084 | struct config_item *s_item = &subsys->su_group.cg_item; | |
b7c177fc | 1085 | struct dentry *root; |
631d1feb JB |
1086 | |
1087 | /* | |
1088 | * Pin the configfs filesystem. This means we can safely access | |
1089 | * the root of the configfs filesystem. | |
1090 | */ | |
2a152ad3 AV |
1091 | root = configfs_pin_fs(); |
1092 | if (IS_ERR(root)) | |
1093 | return PTR_ERR(root); | |
631d1feb JB |
1094 | |
1095 | /* | |
1096 | * Next, lock the root directory. We're going to check that the | |
1097 | * subsystem is really registered, and so we need to lock out | |
1098 | * configfs_[un]register_subsystem(). | |
1099 | */ | |
b7c177fc | 1100 | mutex_lock(&root->d_inode->i_mutex); |
631d1feb | 1101 | |
b7c177fc | 1102 | root_sd = root->d_fsdata; |
631d1feb JB |
1103 | |
1104 | list_for_each_entry(p, &root_sd->s_children, s_sibling) { | |
1105 | if (p->s_type & CONFIGFS_DIR) { | |
1106 | if (p->s_element == s_item) { | |
1107 | subsys_sd = p; | |
1108 | break; | |
1109 | } | |
1110 | } | |
1111 | } | |
1112 | ||
1113 | if (!subsys_sd) { | |
1114 | ret = -ENOENT; | |
1115 | goto out_unlock_fs; | |
1116 | } | |
1117 | ||
1118 | /* Ok, now we can trust subsys/s_item */ | |
1119 | ||
420118ca LR |
1120 | spin_lock(&configfs_dirent_lock); |
1121 | /* Scan the tree, return 0 if found */ | |
631d1feb JB |
1122 | ret = configfs_depend_prep(subsys_sd->s_dentry, target); |
1123 | if (ret) | |
420118ca | 1124 | goto out_unlock_dirent_lock; |
631d1feb | 1125 | |
420118ca LR |
1126 | /* |
1127 | * We are sure that the item is not about to be removed by rmdir(), and | |
1128 | * not in the middle of attachment by mkdir(). | |
1129 | */ | |
631d1feb JB |
1130 | p = target->ci_dentry->d_fsdata; |
1131 | p->s_dependent_count += 1; | |
1132 | ||
420118ca LR |
1133 | out_unlock_dirent_lock: |
1134 | spin_unlock(&configfs_dirent_lock); | |
631d1feb | 1135 | out_unlock_fs: |
b7c177fc | 1136 | mutex_unlock(&root->d_inode->i_mutex); |
631d1feb JB |
1137 | |
1138 | /* | |
1139 | * If we succeeded, the fs is pinned via other methods. If not, | |
1140 | * we're done with it anyway. So release_fs() is always right. | |
1141 | */ | |
1142 | configfs_release_fs(); | |
1143 | ||
1144 | return ret; | |
1145 | } | |
1146 | EXPORT_SYMBOL(configfs_depend_item); | |
1147 | ||
1148 | /* | |
1149 | * Release the dependent linkage. This is much simpler than | |
1150 | * configfs_depend_item() because we know that that the client driver is | |
1151 | * pinned, thus the subsystem is pinned, and therefore configfs is pinned. | |
1152 | */ | |
1153 | void configfs_undepend_item(struct configfs_subsystem *subsys, | |
1154 | struct config_item *target) | |
1155 | { | |
1156 | struct configfs_dirent *sd; | |
1157 | ||
1158 | /* | |
420118ca LR |
1159 | * Since we can trust everything is pinned, we just need |
1160 | * configfs_dirent_lock. | |
631d1feb | 1161 | */ |
420118ca | 1162 | spin_lock(&configfs_dirent_lock); |
631d1feb JB |
1163 | |
1164 | sd = target->ci_dentry->d_fsdata; | |
1165 | BUG_ON(sd->s_dependent_count < 1); | |
1166 | ||
1167 | sd->s_dependent_count -= 1; | |
1168 | ||
1169 | /* | |
1170 | * After this unlock, we cannot trust the item to stay alive! | |
1171 | * DO NOT REFERENCE item after this unlock. | |
1172 | */ | |
420118ca | 1173 | spin_unlock(&configfs_dirent_lock); |
631d1feb JB |
1174 | } |
1175 | EXPORT_SYMBOL(configfs_undepend_item); | |
7063fbf2 | 1176 | |
18bb1db3 | 1177 | static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) |
7063fbf2 | 1178 | { |
a6795e9e JB |
1179 | int ret = 0; |
1180 | int module_got = 0; | |
1181 | struct config_group *group = NULL; | |
1182 | struct config_item *item = NULL; | |
7063fbf2 JB |
1183 | struct config_item *parent_item; |
1184 | struct configfs_subsystem *subsys; | |
1185 | struct configfs_dirent *sd; | |
1186 | struct config_item_type *type; | |
70526b67 | 1187 | struct module *subsys_owner = NULL, *new_item_owner = NULL; |
7063fbf2 JB |
1188 | char *name; |
1189 | ||
7063fbf2 | 1190 | sd = dentry->d_parent->d_fsdata; |
2a109f2a LR |
1191 | |
1192 | /* | |
1193 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
1194 | * being attached | |
1195 | */ | |
1196 | if (!configfs_dirent_is_ready(sd)) { | |
1197 | ret = -ENOENT; | |
1198 | goto out; | |
1199 | } | |
1200 | ||
84efad1a JB |
1201 | if (!(sd->s_type & CONFIGFS_USET_DIR)) { |
1202 | ret = -EPERM; | |
1203 | goto out; | |
1204 | } | |
7063fbf2 | 1205 | |
84efad1a | 1206 | /* Get a working ref for the duration of this function */ |
7063fbf2 JB |
1207 | parent_item = configfs_get_config_item(dentry->d_parent); |
1208 | type = parent_item->ci_type; | |
1209 | subsys = to_config_group(parent_item)->cg_subsys; | |
1210 | BUG_ON(!subsys); | |
1211 | ||
1212 | if (!type || !type->ct_group_ops || | |
1213 | (!type->ct_group_ops->make_group && | |
1214 | !type->ct_group_ops->make_item)) { | |
84efad1a JB |
1215 | ret = -EPERM; /* Lack-of-mkdir returns -EPERM */ |
1216 | goto out_put; | |
7063fbf2 JB |
1217 | } |
1218 | ||
70526b67 JB |
1219 | /* |
1220 | * The subsystem may belong to a different module than the item | |
1221 | * being created. We don't want to safely pin the new item but | |
1222 | * fail to pin the subsystem it sits under. | |
1223 | */ | |
1224 | if (!subsys->su_group.cg_item.ci_type) { | |
1225 | ret = -EINVAL; | |
1226 | goto out_put; | |
1227 | } | |
1228 | subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; | |
1229 | if (!try_module_get(subsys_owner)) { | |
1230 | ret = -EINVAL; | |
1231 | goto out_put; | |
1232 | } | |
1233 | ||
7063fbf2 JB |
1234 | name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL); |
1235 | if (!name) { | |
84efad1a | 1236 | ret = -ENOMEM; |
70526b67 | 1237 | goto out_subsys_put; |
7063fbf2 | 1238 | } |
84efad1a | 1239 | |
7063fbf2 JB |
1240 | snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name); |
1241 | ||
e6bd07ae | 1242 | mutex_lock(&subsys->su_mutex); |
7063fbf2 | 1243 | if (type->ct_group_ops->make_group) { |
f89ab861 | 1244 | group = type->ct_group_ops->make_group(to_config_group(parent_item), name); |
a6795e9e JB |
1245 | if (!group) |
1246 | group = ERR_PTR(-ENOMEM); | |
1247 | if (!IS_ERR(group)) { | |
7063fbf2 JB |
1248 | link_group(to_config_group(parent_item), group); |
1249 | item = &group->cg_item; | |
a6795e9e JB |
1250 | } else |
1251 | ret = PTR_ERR(group); | |
7063fbf2 | 1252 | } else { |
f89ab861 | 1253 | item = type->ct_group_ops->make_item(to_config_group(parent_item), name); |
a6795e9e JB |
1254 | if (!item) |
1255 | item = ERR_PTR(-ENOMEM); | |
1256 | if (!IS_ERR(item)) | |
7063fbf2 | 1257 | link_obj(parent_item, item); |
a6795e9e JB |
1258 | else |
1259 | ret = PTR_ERR(item); | |
7063fbf2 | 1260 | } |
e6bd07ae | 1261 | mutex_unlock(&subsys->su_mutex); |
7063fbf2 JB |
1262 | |
1263 | kfree(name); | |
a6795e9e | 1264 | if (ret) { |
eed7a0db | 1265 | /* |
dacdd0e0 | 1266 | * If ret != 0, then link_obj() was never called. |
eed7a0db JB |
1267 | * There are no extra references to clean up. |
1268 | */ | |
70526b67 | 1269 | goto out_subsys_put; |
7063fbf2 JB |
1270 | } |
1271 | ||
eed7a0db JB |
1272 | /* |
1273 | * link_obj() has been called (via link_group() for groups). | |
1274 | * From here on out, errors must clean that up. | |
1275 | */ | |
1276 | ||
7063fbf2 | 1277 | type = item->ci_type; |
eed7a0db JB |
1278 | if (!type) { |
1279 | ret = -EINVAL; | |
1280 | goto out_unlink; | |
1281 | } | |
7063fbf2 | 1282 | |
70526b67 JB |
1283 | new_item_owner = type->ct_owner; |
1284 | if (!try_module_get(new_item_owner)) { | |
eed7a0db JB |
1285 | ret = -EINVAL; |
1286 | goto out_unlink; | |
1287 | } | |
7063fbf2 | 1288 | |
eed7a0db JB |
1289 | /* |
1290 | * I hate doing it this way, but if there is | |
1291 | * an error, module_put() probably should | |
1292 | * happen after any cleanup. | |
1293 | */ | |
1294 | module_got = 1; | |
1295 | ||
6d8344ba LR |
1296 | /* |
1297 | * Make racing rmdir() fail if it did not tag parent with | |
1298 | * CONFIGFS_USET_DROPPING | |
1299 | * Note: if CONFIGFS_USET_DROPPING is already set, attach_group() will | |
1300 | * fail and let rmdir() terminate correctly | |
1301 | */ | |
1302 | spin_lock(&configfs_dirent_lock); | |
1303 | /* This will make configfs_detach_prep() fail */ | |
1304 | sd->s_type |= CONFIGFS_USET_IN_MKDIR; | |
1305 | spin_unlock(&configfs_dirent_lock); | |
1306 | ||
eed7a0db JB |
1307 | if (group) |
1308 | ret = configfs_attach_group(parent_item, item, dentry); | |
1309 | else | |
1310 | ret = configfs_attach_item(parent_item, item, dentry); | |
1311 | ||
6d8344ba LR |
1312 | spin_lock(&configfs_dirent_lock); |
1313 | sd->s_type &= ~CONFIGFS_USET_IN_MKDIR; | |
2a109f2a LR |
1314 | if (!ret) |
1315 | configfs_dir_set_ready(dentry->d_fsdata); | |
6d8344ba LR |
1316 | spin_unlock(&configfs_dirent_lock); |
1317 | ||
eed7a0db JB |
1318 | out_unlink: |
1319 | if (ret) { | |
1320 | /* Tear down everything we built up */ | |
e6bd07ae | 1321 | mutex_lock(&subsys->su_mutex); |
299894cc JB |
1322 | |
1323 | client_disconnect_notify(parent_item, item); | |
eed7a0db JB |
1324 | if (group) |
1325 | unlink_group(group); | |
1326 | else | |
1327 | unlink_obj(item); | |
1328 | client_drop_item(parent_item, item); | |
299894cc | 1329 | |
e6bd07ae | 1330 | mutex_unlock(&subsys->su_mutex); |
eed7a0db JB |
1331 | |
1332 | if (module_got) | |
70526b67 | 1333 | module_put(new_item_owner); |
7063fbf2 JB |
1334 | } |
1335 | ||
70526b67 JB |
1336 | out_subsys_put: |
1337 | if (ret) | |
1338 | module_put(subsys_owner); | |
1339 | ||
84efad1a JB |
1340 | out_put: |
1341 | /* | |
eed7a0db JB |
1342 | * link_obj()/link_group() took a reference from child->parent, |
1343 | * so the parent is safely pinned. We can drop our working | |
1344 | * reference. | |
84efad1a JB |
1345 | */ |
1346 | config_item_put(parent_item); | |
1347 | ||
1348 | out: | |
7063fbf2 JB |
1349 | return ret; |
1350 | } | |
1351 | ||
1352 | static int configfs_rmdir(struct inode *dir, struct dentry *dentry) | |
1353 | { | |
1354 | struct config_item *parent_item; | |
1355 | struct config_item *item; | |
1356 | struct configfs_subsystem *subsys; | |
1357 | struct configfs_dirent *sd; | |
70526b67 | 1358 | struct module *subsys_owner = NULL, *dead_item_owner = NULL; |
7063fbf2 JB |
1359 | int ret; |
1360 | ||
7063fbf2 JB |
1361 | sd = dentry->d_fsdata; |
1362 | if (sd->s_type & CONFIGFS_USET_DEFAULT) | |
1363 | return -EPERM; | |
1364 | ||
84efad1a | 1365 | /* Get a working ref until we have the child */ |
7063fbf2 JB |
1366 | parent_item = configfs_get_config_item(dentry->d_parent); |
1367 | subsys = to_config_group(parent_item)->cg_subsys; | |
1368 | BUG_ON(!subsys); | |
1369 | ||
1370 | if (!parent_item->ci_type) { | |
1371 | config_item_put(parent_item); | |
1372 | return -EINVAL; | |
1373 | } | |
1374 | ||
70526b67 JB |
1375 | /* configfs_mkdir() shouldn't have allowed this */ |
1376 | BUG_ON(!subsys->su_group.cg_item.ci_type); | |
1377 | subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; | |
1378 | ||
9a73d78c LR |
1379 | /* |
1380 | * Ensure that no racing symlink() will make detach_prep() fail while | |
1381 | * the new link is temporarily attached | |
1382 | */ | |
6d8344ba LR |
1383 | do { |
1384 | struct mutex *wait_mutex; | |
1385 | ||
de6bf18e LR |
1386 | mutex_lock(&configfs_symlink_mutex); |
1387 | spin_lock(&configfs_dirent_lock); | |
420118ca LR |
1388 | /* |
1389 | * Here's where we check for dependents. We're protected by | |
1390 | * configfs_dirent_lock. | |
1391 | * If no dependent, atomically tag the item as dropping. | |
1392 | */ | |
1393 | ret = sd->s_dependent_count ? -EBUSY : 0; | |
1394 | if (!ret) { | |
1395 | ret = configfs_detach_prep(dentry, &wait_mutex); | |
1396 | if (ret) | |
1397 | configfs_detach_rollback(dentry); | |
1398 | } | |
de6bf18e LR |
1399 | spin_unlock(&configfs_dirent_lock); |
1400 | mutex_unlock(&configfs_symlink_mutex); | |
1401 | ||
1402 | if (ret) { | |
6d8344ba LR |
1403 | if (ret != -EAGAIN) { |
1404 | config_item_put(parent_item); | |
1405 | return ret; | |
1406 | } | |
1407 | ||
1408 | /* Wait until the racing operation terminates */ | |
1409 | mutex_lock(wait_mutex); | |
1410 | mutex_unlock(wait_mutex); | |
6d8344ba LR |
1411 | } |
1412 | } while (ret == -EAGAIN); | |
7063fbf2 | 1413 | |
84efad1a | 1414 | /* Get a working ref for the duration of this function */ |
7063fbf2 JB |
1415 | item = configfs_get_config_item(dentry); |
1416 | ||
1417 | /* Drop reference from above, item already holds one. */ | |
1418 | config_item_put(parent_item); | |
1419 | ||
1420 | if (item->ci_type) | |
70526b67 | 1421 | dead_item_owner = item->ci_type->ct_owner; |
7063fbf2 JB |
1422 | |
1423 | if (sd->s_type & CONFIGFS_USET_DIR) { | |
1424 | configfs_detach_group(item); | |
1425 | ||
e6bd07ae | 1426 | mutex_lock(&subsys->su_mutex); |
299894cc | 1427 | client_disconnect_notify(parent_item, item); |
7063fbf2 JB |
1428 | unlink_group(to_config_group(item)); |
1429 | } else { | |
1430 | configfs_detach_item(item); | |
1431 | ||
e6bd07ae | 1432 | mutex_lock(&subsys->su_mutex); |
299894cc | 1433 | client_disconnect_notify(parent_item, item); |
7063fbf2 JB |
1434 | unlink_obj(item); |
1435 | } | |
1436 | ||
1437 | client_drop_item(parent_item, item); | |
e6bd07ae | 1438 | mutex_unlock(&subsys->su_mutex); |
7063fbf2 JB |
1439 | |
1440 | /* Drop our reference from above */ | |
1441 | config_item_put(item); | |
1442 | ||
70526b67 JB |
1443 | module_put(dead_item_owner); |
1444 | module_put(subsys_owner); | |
7063fbf2 JB |
1445 | |
1446 | return 0; | |
1447 | } | |
1448 | ||
754661f1 | 1449 | const struct inode_operations configfs_dir_inode_operations = { |
7063fbf2 JB |
1450 | .mkdir = configfs_mkdir, |
1451 | .rmdir = configfs_rmdir, | |
1452 | .symlink = configfs_symlink, | |
1453 | .unlink = configfs_unlink, | |
1454 | .lookup = configfs_lookup, | |
3d0f89bb | 1455 | .setattr = configfs_setattr, |
7063fbf2 JB |
1456 | }; |
1457 | ||
81d44ed1 AV |
1458 | const struct inode_operations configfs_root_inode_operations = { |
1459 | .lookup = configfs_lookup, | |
1460 | .setattr = configfs_setattr, | |
1461 | }; | |
1462 | ||
7063fbf2 JB |
1463 | #if 0 |
1464 | int configfs_rename_dir(struct config_item * item, const char *new_name) | |
1465 | { | |
1466 | int error = 0; | |
1467 | struct dentry * new_dentry, * parent; | |
1468 | ||
1469 | if (!strcmp(config_item_name(item), new_name)) | |
1470 | return -EINVAL; | |
1471 | ||
1472 | if (!item->parent) | |
1473 | return -EINVAL; | |
1474 | ||
1475 | down_write(&configfs_rename_sem); | |
1476 | parent = item->parent->dentry; | |
1477 | ||
1b1dcc1b | 1478 | mutex_lock(&parent->d_inode->i_mutex); |
7063fbf2 JB |
1479 | |
1480 | new_dentry = lookup_one_len(new_name, parent, strlen(new_name)); | |
1481 | if (!IS_ERR(new_dentry)) { | |
e7515d06 | 1482 | if (!new_dentry->d_inode) { |
7063fbf2 JB |
1483 | error = config_item_set_name(item, "%s", new_name); |
1484 | if (!error) { | |
1485 | d_add(new_dentry, NULL); | |
1486 | d_move(item->dentry, new_dentry); | |
1487 | } | |
1488 | else | |
1489 | d_delete(new_dentry); | |
1490 | } else | |
1491 | error = -EEXIST; | |
1492 | dput(new_dentry); | |
1493 | } | |
1b1dcc1b | 1494 | mutex_unlock(&parent->d_inode->i_mutex); |
7063fbf2 JB |
1495 | up_write(&configfs_rename_sem); |
1496 | ||
1497 | return error; | |
1498 | } | |
1499 | #endif | |
1500 | ||
1501 | static int configfs_dir_open(struct inode *inode, struct file *file) | |
1502 | { | |
867fa491 | 1503 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 | 1504 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
2a109f2a | 1505 | int err; |
7063fbf2 | 1506 | |
1b1dcc1b | 1507 | mutex_lock(&dentry->d_inode->i_mutex); |
2a109f2a LR |
1508 | /* |
1509 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
1510 | * being attached | |
1511 | */ | |
1512 | err = -ENOENT; | |
1513 | if (configfs_dirent_is_ready(parent_sd)) { | |
420118ca | 1514 | file->private_data = configfs_new_dirent(parent_sd, NULL, 0); |
2a109f2a LR |
1515 | if (IS_ERR(file->private_data)) |
1516 | err = PTR_ERR(file->private_data); | |
1517 | else | |
1518 | err = 0; | |
1519 | } | |
1b1dcc1b | 1520 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 | 1521 | |
2a109f2a | 1522 | return err; |
7063fbf2 JB |
1523 | } |
1524 | ||
1525 | static int configfs_dir_close(struct inode *inode, struct file *file) | |
1526 | { | |
867fa491 | 1527 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 JB |
1528 | struct configfs_dirent * cursor = file->private_data; |
1529 | ||
1b1dcc1b | 1530 | mutex_lock(&dentry->d_inode->i_mutex); |
6f610764 | 1531 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 1532 | list_del_init(&cursor->s_sibling); |
6f610764 | 1533 | spin_unlock(&configfs_dirent_lock); |
1b1dcc1b | 1534 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1535 | |
1536 | release_configfs_dirent(cursor); | |
1537 | ||
1538 | return 0; | |
1539 | } | |
1540 | ||
1541 | /* Relationship between s_mode and the DT_xxx types */ | |
1542 | static inline unsigned char dt_type(struct configfs_dirent *sd) | |
1543 | { | |
1544 | return (sd->s_mode >> 12) & 15; | |
1545 | } | |
1546 | ||
1547 | static int configfs_readdir(struct file * filp, void * dirent, filldir_t filldir) | |
1548 | { | |
867fa491 | 1549 | struct dentry *dentry = filp->f_path.dentry; |
b7c177fc | 1550 | struct super_block *sb = dentry->d_sb; |
7063fbf2 JB |
1551 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
1552 | struct configfs_dirent *cursor = filp->private_data; | |
1553 | struct list_head *p, *q = &cursor->s_sibling; | |
24307aa1 | 1554 | ino_t ino = 0; |
7063fbf2 JB |
1555 | int i = filp->f_pos; |
1556 | ||
1557 | switch (i) { | |
1558 | case 0: | |
1559 | ino = dentry->d_inode->i_ino; | |
1560 | if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) | |
1561 | break; | |
1562 | filp->f_pos++; | |
1563 | i++; | |
1564 | /* fallthrough */ | |
1565 | case 1: | |
1566 | ino = parent_ino(dentry); | |
1567 | if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) | |
1568 | break; | |
1569 | filp->f_pos++; | |
1570 | i++; | |
1571 | /* fallthrough */ | |
1572 | default: | |
1573 | if (filp->f_pos == 2) { | |
6f610764 | 1574 | spin_lock(&configfs_dirent_lock); |
f116629d | 1575 | list_move(q, &parent_sd->s_children); |
6f610764 | 1576 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
1577 | } |
1578 | for (p=q->next; p!= &parent_sd->s_children; p=p->next) { | |
1579 | struct configfs_dirent *next; | |
1580 | const char * name; | |
1581 | int len; | |
24307aa1 | 1582 | struct inode *inode = NULL; |
7063fbf2 JB |
1583 | |
1584 | next = list_entry(p, struct configfs_dirent, | |
1585 | s_sibling); | |
1586 | if (!next->s_element) | |
1587 | continue; | |
1588 | ||
1589 | name = configfs_get_name(next); | |
1590 | len = strlen(name); | |
24307aa1 JB |
1591 | |
1592 | /* | |
1593 | * We'll have a dentry and an inode for | |
1594 | * PINNED items and for open attribute | |
1595 | * files. We lock here to prevent a race | |
1596 | * with configfs_d_iput() clearing | |
1597 | * s_dentry before calling iput(). | |
1598 | * | |
1599 | * Why do we go to the trouble? If | |
1600 | * someone has an attribute file open, | |
1601 | * the inode number should match until | |
1602 | * they close it. Beyond that, we don't | |
1603 | * care. | |
1604 | */ | |
1605 | spin_lock(&configfs_dirent_lock); | |
1606 | dentry = next->s_dentry; | |
1607 | if (dentry) | |
1608 | inode = dentry->d_inode; | |
1609 | if (inode) | |
1610 | ino = inode->i_ino; | |
1611 | spin_unlock(&configfs_dirent_lock); | |
1612 | if (!inode) | |
b7c177fc | 1613 | ino = iunique(sb, 2); |
7063fbf2 JB |
1614 | |
1615 | if (filldir(dirent, name, len, filp->f_pos, ino, | |
1616 | dt_type(next)) < 0) | |
1617 | return 0; | |
1618 | ||
6f610764 | 1619 | spin_lock(&configfs_dirent_lock); |
f116629d | 1620 | list_move(q, p); |
6f610764 | 1621 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
1622 | p = q; |
1623 | filp->f_pos++; | |
1624 | } | |
1625 | } | |
1626 | return 0; | |
1627 | } | |
1628 | ||
965c8e59 | 1629 | static loff_t configfs_dir_lseek(struct file *file, loff_t offset, int whence) |
7063fbf2 | 1630 | { |
867fa491 | 1631 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 | 1632 | |
1b1dcc1b | 1633 | mutex_lock(&dentry->d_inode->i_mutex); |
965c8e59 | 1634 | switch (whence) { |
7063fbf2 JB |
1635 | case 1: |
1636 | offset += file->f_pos; | |
1637 | case 0: | |
1638 | if (offset >= 0) | |
1639 | break; | |
1640 | default: | |
496ad9aa | 1641 | mutex_unlock(&file_inode(file)->i_mutex); |
7063fbf2 JB |
1642 | return -EINVAL; |
1643 | } | |
1644 | if (offset != file->f_pos) { | |
1645 | file->f_pos = offset; | |
1646 | if (file->f_pos >= 2) { | |
1647 | struct configfs_dirent *sd = dentry->d_fsdata; | |
1648 | struct configfs_dirent *cursor = file->private_data; | |
1649 | struct list_head *p; | |
1650 | loff_t n = file->f_pos - 2; | |
1651 | ||
6f610764 | 1652 | spin_lock(&configfs_dirent_lock); |
7063fbf2 JB |
1653 | list_del(&cursor->s_sibling); |
1654 | p = sd->s_children.next; | |
1655 | while (n && p != &sd->s_children) { | |
1656 | struct configfs_dirent *next; | |
1657 | next = list_entry(p, struct configfs_dirent, | |
1658 | s_sibling); | |
1659 | if (next->s_element) | |
1660 | n--; | |
1661 | p = p->next; | |
1662 | } | |
1663 | list_add_tail(&cursor->s_sibling, p); | |
6f610764 | 1664 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
1665 | } |
1666 | } | |
1b1dcc1b | 1667 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1668 | return offset; |
1669 | } | |
1670 | ||
4b6f5d20 | 1671 | const struct file_operations configfs_dir_operations = { |
7063fbf2 JB |
1672 | .open = configfs_dir_open, |
1673 | .release = configfs_dir_close, | |
1674 | .llseek = configfs_dir_lseek, | |
1675 | .read = generic_read_dir, | |
1676 | .readdir = configfs_readdir, | |
1677 | }; | |
1678 | ||
1679 | int configfs_register_subsystem(struct configfs_subsystem *subsys) | |
1680 | { | |
1681 | int err; | |
1682 | struct config_group *group = &subsys->su_group; | |
1683 | struct qstr name; | |
1684 | struct dentry *dentry; | |
b7c177fc | 1685 | struct dentry *root; |
7063fbf2 JB |
1686 | struct configfs_dirent *sd; |
1687 | ||
2a152ad3 AV |
1688 | root = configfs_pin_fs(); |
1689 | if (IS_ERR(root)) | |
1690 | return PTR_ERR(root); | |
7063fbf2 JB |
1691 | |
1692 | if (!group->cg_item.ci_name) | |
1693 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
1694 | ||
b7c177fc | 1695 | sd = root->d_fsdata; |
7063fbf2 JB |
1696 | link_group(to_config_group(sd->s_element), group); |
1697 | ||
b7c177fc | 1698 | mutex_lock_nested(&root->d_inode->i_mutex, I_MUTEX_PARENT); |
7063fbf2 JB |
1699 | |
1700 | name.name = group->cg_item.ci_name; | |
1701 | name.len = strlen(name.name); | |
1702 | name.hash = full_name_hash(name.name, name.len); | |
1703 | ||
1704 | err = -ENOMEM; | |
b7c177fc | 1705 | dentry = d_alloc(root, &name); |
afdf04ea JB |
1706 | if (dentry) { |
1707 | d_add(dentry, NULL); | |
7063fbf2 | 1708 | |
afdf04ea JB |
1709 | err = configfs_attach_group(sd->s_element, &group->cg_item, |
1710 | dentry); | |
1711 | if (err) { | |
df7f9967 JB |
1712 | BUG_ON(dentry->d_inode); |
1713 | d_drop(dentry); | |
afdf04ea | 1714 | dput(dentry); |
2a109f2a LR |
1715 | } else { |
1716 | spin_lock(&configfs_dirent_lock); | |
1717 | configfs_dir_set_ready(dentry->d_fsdata); | |
1718 | spin_unlock(&configfs_dirent_lock); | |
afdf04ea JB |
1719 | } |
1720 | } | |
7063fbf2 | 1721 | |
b7c177fc | 1722 | mutex_unlock(&root->d_inode->i_mutex); |
7063fbf2 | 1723 | |
afdf04ea JB |
1724 | if (err) { |
1725 | unlink_group(group); | |
1726 | configfs_release_fs(); | |
7063fbf2 JB |
1727 | } |
1728 | ||
1729 | return err; | |
1730 | } | |
1731 | ||
1732 | void configfs_unregister_subsystem(struct configfs_subsystem *subsys) | |
1733 | { | |
1734 | struct config_group *group = &subsys->su_group; | |
1735 | struct dentry *dentry = group->cg_item.ci_dentry; | |
b7c177fc | 1736 | struct dentry *root = dentry->d_sb->s_root; |
7063fbf2 | 1737 | |
b7c177fc | 1738 | if (dentry->d_parent != root) { |
7063fbf2 JB |
1739 | printk(KERN_ERR "configfs: Tried to unregister non-subsystem!\n"); |
1740 | return; | |
1741 | } | |
1742 | ||
b7c177fc | 1743 | mutex_lock_nested(&root->d_inode->i_mutex, |
55ed1602 MF |
1744 | I_MUTEX_PARENT); |
1745 | mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); | |
9a73d78c | 1746 | mutex_lock(&configfs_symlink_mutex); |
b3e76af8 | 1747 | spin_lock(&configfs_dirent_lock); |
6d8344ba | 1748 | if (configfs_detach_prep(dentry, NULL)) { |
7063fbf2 JB |
1749 | printk(KERN_ERR "configfs: Tried to unregister non-empty subsystem!\n"); |
1750 | } | |
b3e76af8 | 1751 | spin_unlock(&configfs_dirent_lock); |
9a73d78c | 1752 | mutex_unlock(&configfs_symlink_mutex); |
7063fbf2 JB |
1753 | configfs_detach_group(&group->cg_item); |
1754 | dentry->d_inode->i_flags |= S_DEAD; | |
d83c49f3 | 1755 | dont_mount(dentry); |
1b1dcc1b | 1756 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1757 | |
1758 | d_delete(dentry); | |
1759 | ||
b7c177fc | 1760 | mutex_unlock(&root->d_inode->i_mutex); |
7063fbf2 JB |
1761 | |
1762 | dput(dentry); | |
1763 | ||
1764 | unlink_group(group); | |
1765 | configfs_release_fs(); | |
1766 | } | |
1767 | ||
1768 | EXPORT_SYMBOL(configfs_register_subsystem); | |
1769 | EXPORT_SYMBOL(configfs_unregister_subsystem); |