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7063fbf2 JB |
1 | /* -*- mode: c; c-basic-offset: 8; -*- |
2 | * vim: noexpandtab sw=8 ts=8 sts=0: | |
3 | * | |
4 | * dir.c - Operations for configfs directories. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public | |
8 | * License as published by the Free Software Foundation; either | |
9 | * version 2 of the License, or (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public | |
17 | * License along with this program; if not, write to the | |
18 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
19 | * Boston, MA 021110-1307, USA. | |
20 | * | |
21 | * Based on sysfs: | |
22 | * sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel | |
23 | * | |
24 | * configfs Copyright (C) 2005 Oracle. All rights reserved. | |
25 | */ | |
26 | ||
27 | #undef DEBUG | |
28 | ||
29 | #include <linux/fs.h> | |
30 | #include <linux/mount.h> | |
31 | #include <linux/module.h> | |
32 | #include <linux/slab.h> | |
107ed40b | 33 | #include <linux/err.h> |
7063fbf2 JB |
34 | |
35 | #include <linux/configfs.h> | |
36 | #include "configfs_internal.h" | |
37 | ||
38 | DECLARE_RWSEM(configfs_rename_sem); | |
6f610764 LR |
39 | /* |
40 | * Protects mutations of configfs_dirent linkage together with proper i_mutex | |
5301a77d | 41 | * Also protects mutations of symlinks linkage to target configfs_dirent |
6f610764 LR |
42 | * Mutators of configfs_dirent linkage must *both* have the proper inode locked |
43 | * and configfs_dirent_lock locked, in that order. | |
5301a77d LR |
44 | * This allows one to safely traverse configfs_dirent trees and symlinks without |
45 | * having to lock inodes. | |
b3e76af8 LR |
46 | * |
47 | * Protects setting of CONFIGFS_USET_DROPPING: checking the flag | |
48 | * unlocked is not reliable unless in detach_groups() called from | |
49 | * rmdir()/unregister() and from configfs_attach_group() | |
6f610764 LR |
50 | */ |
51 | DEFINE_SPINLOCK(configfs_dirent_lock); | |
7063fbf2 JB |
52 | |
53 | static void configfs_d_iput(struct dentry * dentry, | |
54 | struct inode * inode) | |
55 | { | |
56 | struct configfs_dirent * sd = dentry->d_fsdata; | |
57 | ||
58 | if (sd) { | |
59 | BUG_ON(sd->s_dentry != dentry); | |
60 | sd->s_dentry = NULL; | |
61 | configfs_put(sd); | |
62 | } | |
63 | iput(inode); | |
64 | } | |
65 | ||
66 | /* | |
67 | * We _must_ delete our dentries on last dput, as the chain-to-parent | |
68 | * behavior is required to clear the parents of default_groups. | |
69 | */ | |
fe15ce44 | 70 | static int configfs_d_delete(const struct dentry *dentry) |
7063fbf2 JB |
71 | { |
72 | return 1; | |
73 | } | |
74 | ||
d463a0c4 | 75 | const struct dentry_operations configfs_dentry_ops = { |
7063fbf2 JB |
76 | .d_iput = configfs_d_iput, |
77 | /* simple_delete_dentry() isn't exported */ | |
78 | .d_delete = configfs_d_delete, | |
79 | }; | |
80 | ||
e74cc06d LR |
81 | #ifdef CONFIG_LOCKDEP |
82 | ||
83 | /* | |
84 | * Helpers to make lockdep happy with our recursive locking of default groups' | |
85 | * inodes (see configfs_attach_group() and configfs_detach_group()). | |
86 | * We put default groups i_mutexes in separate classes according to their depth | |
87 | * from the youngest non-default group ancestor. | |
88 | * | |
89 | * For a non-default group A having default groups A/B, A/C, and A/C/D, default | |
90 | * groups A/B and A/C will have their inode's mutex in class | |
91 | * default_group_class[0], and default group A/C/D will be in | |
92 | * default_group_class[1]. | |
93 | * | |
94 | * The lock classes are declared and assigned in inode.c, according to the | |
95 | * s_depth value. | |
96 | * The s_depth value is initialized to -1, adjusted to >= 0 when attaching | |
97 | * default groups, and reset to -1 when all default groups are attached. During | |
98 | * attachment, if configfs_create() sees s_depth > 0, the lock class of the new | |
99 | * inode's mutex is set to default_group_class[s_depth - 1]. | |
100 | */ | |
101 | ||
102 | static void configfs_init_dirent_depth(struct configfs_dirent *sd) | |
103 | { | |
104 | sd->s_depth = -1; | |
105 | } | |
106 | ||
107 | static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd, | |
108 | struct configfs_dirent *sd) | |
109 | { | |
110 | int parent_depth = parent_sd->s_depth; | |
111 | ||
112 | if (parent_depth >= 0) | |
113 | sd->s_depth = parent_depth + 1; | |
114 | } | |
115 | ||
116 | static void | |
117 | configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd) | |
118 | { | |
119 | /* | |
120 | * item's i_mutex class is already setup, so s_depth is now only | |
121 | * used to set new sub-directories s_depth, which is always done | |
122 | * with item's i_mutex locked. | |
123 | */ | |
124 | /* | |
125 | * sd->s_depth == -1 iff we are a non default group. | |
126 | * else (we are a default group) sd->s_depth > 0 (see | |
127 | * create_dir()). | |
128 | */ | |
129 | if (sd->s_depth == -1) | |
130 | /* | |
131 | * We are a non default group and we are going to create | |
132 | * default groups. | |
133 | */ | |
134 | sd->s_depth = 0; | |
135 | } | |
136 | ||
137 | static void | |
138 | configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd) | |
139 | { | |
140 | /* We will not create default groups anymore. */ | |
141 | sd->s_depth = -1; | |
142 | } | |
143 | ||
144 | #else /* CONFIG_LOCKDEP */ | |
145 | ||
146 | static void configfs_init_dirent_depth(struct configfs_dirent *sd) | |
147 | { | |
148 | } | |
149 | ||
150 | static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd, | |
151 | struct configfs_dirent *sd) | |
152 | { | |
153 | } | |
154 | ||
155 | static void | |
156 | configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd) | |
157 | { | |
158 | } | |
159 | ||
160 | static void | |
161 | configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd) | |
162 | { | |
163 | } | |
164 | ||
165 | #endif /* CONFIG_LOCKDEP */ | |
166 | ||
7063fbf2 JB |
167 | /* |
168 | * Allocates a new configfs_dirent and links it to the parent configfs_dirent | |
169 | */ | |
420118ca LR |
170 | static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *parent_sd, |
171 | void *element, int type) | |
7063fbf2 JB |
172 | { |
173 | struct configfs_dirent * sd; | |
174 | ||
c3762229 | 175 | sd = kmem_cache_zalloc(configfs_dir_cachep, GFP_KERNEL); |
7063fbf2 | 176 | if (!sd) |
107ed40b | 177 | return ERR_PTR(-ENOMEM); |
7063fbf2 | 178 | |
7063fbf2 JB |
179 | atomic_set(&sd->s_count, 1); |
180 | INIT_LIST_HEAD(&sd->s_links); | |
181 | INIT_LIST_HEAD(&sd->s_children); | |
7063fbf2 | 182 | sd->s_element = element; |
420118ca | 183 | sd->s_type = type; |
e74cc06d | 184 | configfs_init_dirent_depth(sd); |
6f610764 | 185 | spin_lock(&configfs_dirent_lock); |
b3e76af8 LR |
186 | if (parent_sd->s_type & CONFIGFS_USET_DROPPING) { |
187 | spin_unlock(&configfs_dirent_lock); | |
188 | kmem_cache_free(configfs_dir_cachep, sd); | |
189 | return ERR_PTR(-ENOENT); | |
190 | } | |
6f610764 LR |
191 | list_add(&sd->s_sibling, &parent_sd->s_children); |
192 | spin_unlock(&configfs_dirent_lock); | |
7063fbf2 JB |
193 | |
194 | return sd; | |
195 | } | |
196 | ||
b4c98f62 JB |
197 | /* |
198 | * | |
199 | * Return -EEXIST if there is already a configfs element with the same | |
200 | * name for the same parent. | |
201 | * | |
202 | * called with parent inode's i_mutex held | |
203 | */ | |
58d206c2 AB |
204 | static int configfs_dirent_exists(struct configfs_dirent *parent_sd, |
205 | const unsigned char *new) | |
b4c98f62 JB |
206 | { |
207 | struct configfs_dirent * sd; | |
208 | ||
209 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
210 | if (sd->s_element) { | |
211 | const unsigned char *existing = configfs_get_name(sd); | |
212 | if (strcmp(existing, new)) | |
213 | continue; | |
214 | else | |
215 | return -EEXIST; | |
216 | } | |
217 | } | |
218 | ||
219 | return 0; | |
220 | } | |
221 | ||
222 | ||
7063fbf2 JB |
223 | int configfs_make_dirent(struct configfs_dirent * parent_sd, |
224 | struct dentry * dentry, void * element, | |
225 | umode_t mode, int type) | |
226 | { | |
227 | struct configfs_dirent * sd; | |
228 | ||
420118ca | 229 | sd = configfs_new_dirent(parent_sd, element, type); |
107ed40b LR |
230 | if (IS_ERR(sd)) |
231 | return PTR_ERR(sd); | |
7063fbf2 JB |
232 | |
233 | sd->s_mode = mode; | |
7063fbf2 | 234 | sd->s_dentry = dentry; |
fbc8d4c0 | 235 | if (dentry) |
7063fbf2 | 236 | dentry->d_fsdata = configfs_get(sd); |
7063fbf2 JB |
237 | |
238 | return 0; | |
239 | } | |
240 | ||
241 | static int init_dir(struct inode * inode) | |
242 | { | |
243 | inode->i_op = &configfs_dir_inode_operations; | |
244 | inode->i_fop = &configfs_dir_operations; | |
245 | ||
246 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |
d8c76e6f | 247 | inc_nlink(inode); |
7063fbf2 JB |
248 | return 0; |
249 | } | |
250 | ||
ce8d2cdf | 251 | static int configfs_init_file(struct inode * inode) |
7063fbf2 JB |
252 | { |
253 | inode->i_size = PAGE_SIZE; | |
254 | inode->i_fop = &configfs_file_operations; | |
255 | return 0; | |
256 | } | |
257 | ||
258 | static int init_symlink(struct inode * inode) | |
259 | { | |
260 | inode->i_op = &configfs_symlink_inode_operations; | |
261 | return 0; | |
262 | } | |
263 | ||
264 | static int create_dir(struct config_item * k, struct dentry * p, | |
265 | struct dentry * d) | |
266 | { | |
267 | int error; | |
268 | umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; | |
269 | ||
b4c98f62 JB |
270 | error = configfs_dirent_exists(p->d_fsdata, d->d_name.name); |
271 | if (!error) | |
272 | error = configfs_make_dirent(p->d_fsdata, d, k, mode, | |
2a109f2a | 273 | CONFIGFS_DIR | CONFIGFS_USET_CREATING); |
7063fbf2 | 274 | if (!error) { |
e74cc06d | 275 | configfs_set_dir_dirent_depth(p->d_fsdata, d->d_fsdata); |
3d0f89bb | 276 | error = configfs_create(d, mode, init_dir); |
7063fbf2 | 277 | if (!error) { |
d8c76e6f | 278 | inc_nlink(p->d_inode); |
3d0f89bb JB |
279 | } else { |
280 | struct configfs_dirent *sd = d->d_fsdata; | |
281 | if (sd) { | |
6f610764 | 282 | spin_lock(&configfs_dirent_lock); |
3d0f89bb | 283 | list_del_init(&sd->s_sibling); |
6f610764 | 284 | spin_unlock(&configfs_dirent_lock); |
3d0f89bb JB |
285 | configfs_put(sd); |
286 | } | |
7063fbf2 JB |
287 | } |
288 | } | |
289 | return error; | |
290 | } | |
291 | ||
292 | ||
293 | /** | |
294 | * configfs_create_dir - create a directory for an config_item. | |
295 | * @item: config_itemwe're creating directory for. | |
296 | * @dentry: config_item's dentry. | |
2a109f2a LR |
297 | * |
298 | * Note: user-created entries won't be allowed under this new directory | |
299 | * until it is validated by configfs_dir_set_ready() | |
7063fbf2 JB |
300 | */ |
301 | ||
302 | static int configfs_create_dir(struct config_item * item, struct dentry *dentry) | |
303 | { | |
304 | struct dentry * parent; | |
305 | int error = 0; | |
306 | ||
307 | BUG_ON(!item); | |
308 | ||
309 | if (item->ci_parent) | |
310 | parent = item->ci_parent->ci_dentry; | |
311 | else if (configfs_mount && configfs_mount->mnt_sb) | |
312 | parent = configfs_mount->mnt_sb->s_root; | |
313 | else | |
314 | return -EFAULT; | |
315 | ||
316 | error = create_dir(item,parent,dentry); | |
317 | if (!error) | |
318 | item->ci_dentry = dentry; | |
319 | return error; | |
320 | } | |
321 | ||
2a109f2a LR |
322 | /* |
323 | * Allow userspace to create new entries under a new directory created with | |
324 | * configfs_create_dir(), and under all of its chidlren directories recursively. | |
325 | * @sd configfs_dirent of the new directory to validate | |
326 | * | |
327 | * Caller must hold configfs_dirent_lock. | |
328 | */ | |
329 | static void configfs_dir_set_ready(struct configfs_dirent *sd) | |
330 | { | |
331 | struct configfs_dirent *child_sd; | |
332 | ||
333 | sd->s_type &= ~CONFIGFS_USET_CREATING; | |
334 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) | |
335 | if (child_sd->s_type & CONFIGFS_USET_CREATING) | |
336 | configfs_dir_set_ready(child_sd); | |
337 | } | |
338 | ||
339 | /* | |
340 | * Check that a directory does not belong to a directory hierarchy being | |
341 | * attached and not validated yet. | |
342 | * @sd configfs_dirent of the directory to check | |
343 | * | |
344 | * @return non-zero iff the directory was validated | |
345 | * | |
346 | * Note: takes configfs_dirent_lock, so the result may change from false to true | |
347 | * in two consecutive calls, but never from true to false. | |
348 | */ | |
349 | int configfs_dirent_is_ready(struct configfs_dirent *sd) | |
350 | { | |
351 | int ret; | |
352 | ||
353 | spin_lock(&configfs_dirent_lock); | |
354 | ret = !(sd->s_type & CONFIGFS_USET_CREATING); | |
355 | spin_unlock(&configfs_dirent_lock); | |
356 | ||
357 | return ret; | |
358 | } | |
359 | ||
7063fbf2 JB |
360 | int configfs_create_link(struct configfs_symlink *sl, |
361 | struct dentry *parent, | |
362 | struct dentry *dentry) | |
363 | { | |
364 | int err = 0; | |
365 | umode_t mode = S_IFLNK | S_IRWXUGO; | |
366 | ||
3d0f89bb JB |
367 | err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode, |
368 | CONFIGFS_ITEM_LINK); | |
7063fbf2 | 369 | if (!err) { |
3d0f89bb | 370 | err = configfs_create(dentry, mode, init_symlink); |
fbc8d4c0 | 371 | if (err) { |
3d0f89bb JB |
372 | struct configfs_dirent *sd = dentry->d_fsdata; |
373 | if (sd) { | |
6f610764 | 374 | spin_lock(&configfs_dirent_lock); |
3d0f89bb | 375 | list_del_init(&sd->s_sibling); |
6f610764 | 376 | spin_unlock(&configfs_dirent_lock); |
3d0f89bb JB |
377 | configfs_put(sd); |
378 | } | |
379 | } | |
7063fbf2 JB |
380 | } |
381 | return err; | |
382 | } | |
383 | ||
384 | static void remove_dir(struct dentry * d) | |
385 | { | |
386 | struct dentry * parent = dget(d->d_parent); | |
387 | struct configfs_dirent * sd; | |
388 | ||
389 | sd = d->d_fsdata; | |
6f610764 | 390 | spin_lock(&configfs_dirent_lock); |
e7515d06 | 391 | list_del_init(&sd->s_sibling); |
6f610764 | 392 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
393 | configfs_put(sd); |
394 | if (d->d_inode) | |
395 | simple_rmdir(parent->d_inode,d); | |
396 | ||
b7ab39f6 | 397 | pr_debug(" o %s removing done (%d)\n",d->d_name.name, d->d_count); |
7063fbf2 JB |
398 | |
399 | dput(parent); | |
400 | } | |
401 | ||
402 | /** | |
403 | * configfs_remove_dir - remove an config_item's directory. | |
404 | * @item: config_item we're removing. | |
405 | * | |
406 | * The only thing special about this is that we remove any files in | |
407 | * the directory before we remove the directory, and we've inlined | |
408 | * what used to be configfs_rmdir() below, instead of calling separately. | |
2e2ce171 LR |
409 | * |
410 | * Caller holds the mutex of the item's inode | |
7063fbf2 JB |
411 | */ |
412 | ||
413 | static void configfs_remove_dir(struct config_item * item) | |
414 | { | |
415 | struct dentry * dentry = dget(item->ci_dentry); | |
416 | ||
417 | if (!dentry) | |
418 | return; | |
419 | ||
420 | remove_dir(dentry); | |
421 | /** | |
422 | * Drop reference from dget() on entrance. | |
423 | */ | |
424 | dput(dentry); | |
425 | } | |
426 | ||
427 | ||
428 | /* attaches attribute's configfs_dirent to the dentry corresponding to the | |
429 | * attribute file | |
430 | */ | |
431 | static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry) | |
432 | { | |
433 | struct configfs_attribute * attr = sd->s_element; | |
434 | int error; | |
435 | ||
3d0f89bb JB |
436 | dentry->d_fsdata = configfs_get(sd); |
437 | sd->s_dentry = dentry; | |
ce8d2cdf DH |
438 | error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG, |
439 | configfs_init_file); | |
3d0f89bb JB |
440 | if (error) { |
441 | configfs_put(sd); | |
7063fbf2 | 442 | return error; |
3d0f89bb | 443 | } |
7063fbf2 | 444 | |
7063fbf2 JB |
445 | d_rehash(dentry); |
446 | ||
447 | return 0; | |
448 | } | |
449 | ||
450 | static struct dentry * configfs_lookup(struct inode *dir, | |
451 | struct dentry *dentry, | |
452 | struct nameidata *nd) | |
453 | { | |
454 | struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata; | |
455 | struct configfs_dirent * sd; | |
456 | int found = 0; | |
2a109f2a LR |
457 | int err; |
458 | ||
459 | /* | |
460 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
461 | * being attached | |
462 | * | |
463 | * This forbids userspace to read/write attributes of items which may | |
464 | * not complete their initialization, since the dentries of the | |
465 | * attributes won't be instantiated. | |
466 | */ | |
467 | err = -ENOENT; | |
468 | if (!configfs_dirent_is_ready(parent_sd)) | |
469 | goto out; | |
7063fbf2 JB |
470 | |
471 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
472 | if (sd->s_type & CONFIGFS_NOT_PINNED) { | |
473 | const unsigned char * name = configfs_get_name(sd); | |
474 | ||
475 | if (strcmp(name, dentry->d_name.name)) | |
476 | continue; | |
477 | ||
478 | found = 1; | |
479 | err = configfs_attach_attr(sd, dentry); | |
480 | break; | |
481 | } | |
482 | } | |
483 | ||
484 | if (!found) { | |
485 | /* | |
486 | * If it doesn't exist and it isn't a NOT_PINNED item, | |
487 | * it must be negative. | |
488 | */ | |
fbc8d4c0 NP |
489 | if (dentry->d_name.len > NAME_MAX) |
490 | return ERR_PTR(-ENAMETOOLONG); | |
fbc8d4c0 NP |
491 | d_add(dentry, NULL); |
492 | return NULL; | |
7063fbf2 JB |
493 | } |
494 | ||
2a109f2a | 495 | out: |
7063fbf2 JB |
496 | return ERR_PTR(err); |
497 | } | |
498 | ||
499 | /* | |
500 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are | |
b3e76af8 LR |
501 | * attributes and are removed by rmdir(). We recurse, setting |
502 | * CONFIGFS_USET_DROPPING on all children that are candidates for | |
503 | * default detach. | |
504 | * If there is an error, the caller will reset the flags via | |
505 | * configfs_detach_rollback(). | |
7063fbf2 | 506 | */ |
6d8344ba | 507 | static int configfs_detach_prep(struct dentry *dentry, struct mutex **wait_mutex) |
7063fbf2 JB |
508 | { |
509 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
510 | struct configfs_dirent *sd; | |
511 | int ret; | |
512 | ||
4768e9b1 LR |
513 | /* Mark that we're trying to drop the group */ |
514 | parent_sd->s_type |= CONFIGFS_USET_DROPPING; | |
515 | ||
7063fbf2 JB |
516 | ret = -EBUSY; |
517 | if (!list_empty(&parent_sd->s_links)) | |
518 | goto out; | |
519 | ||
520 | ret = 0; | |
521 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
99cefda4 LR |
522 | if (!sd->s_element || |
523 | (sd->s_type & CONFIGFS_NOT_PINNED)) | |
7063fbf2 JB |
524 | continue; |
525 | if (sd->s_type & CONFIGFS_USET_DEFAULT) { | |
6d8344ba LR |
526 | /* Abort if racing with mkdir() */ |
527 | if (sd->s_type & CONFIGFS_USET_IN_MKDIR) { | |
528 | if (wait_mutex) | |
529 | *wait_mutex = &sd->s_dentry->d_inode->i_mutex; | |
530 | return -EAGAIN; | |
531 | } | |
7063fbf2 | 532 | |
631d1feb JB |
533 | /* |
534 | * Yup, recursive. If there's a problem, blame | |
535 | * deep nesting of default_groups | |
536 | */ | |
6d8344ba | 537 | ret = configfs_detach_prep(sd->s_dentry, wait_mutex); |
7063fbf2 | 538 | if (!ret) |
e7515d06 | 539 | continue; |
7063fbf2 JB |
540 | } else |
541 | ret = -ENOTEMPTY; | |
542 | ||
543 | break; | |
544 | } | |
545 | ||
546 | out: | |
547 | return ret; | |
548 | } | |
549 | ||
550 | /* | |
b3e76af8 | 551 | * Walk the tree, resetting CONFIGFS_USET_DROPPING wherever it was |
7063fbf2 JB |
552 | * set. |
553 | */ | |
554 | static void configfs_detach_rollback(struct dentry *dentry) | |
555 | { | |
556 | struct configfs_dirent *parent_sd = dentry->d_fsdata; | |
557 | struct configfs_dirent *sd; | |
558 | ||
4768e9b1 LR |
559 | parent_sd->s_type &= ~CONFIGFS_USET_DROPPING; |
560 | ||
561 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) | |
562 | if (sd->s_type & CONFIGFS_USET_DEFAULT) | |
7063fbf2 | 563 | configfs_detach_rollback(sd->s_dentry); |
7063fbf2 JB |
564 | } |
565 | ||
566 | static void detach_attrs(struct config_item * item) | |
567 | { | |
568 | struct dentry * dentry = dget(item->ci_dentry); | |
569 | struct configfs_dirent * parent_sd; | |
570 | struct configfs_dirent * sd, * tmp; | |
571 | ||
572 | if (!dentry) | |
573 | return; | |
574 | ||
575 | pr_debug("configfs %s: dropping attrs for dir\n", | |
576 | dentry->d_name.name); | |
577 | ||
578 | parent_sd = dentry->d_fsdata; | |
579 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
580 | if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED)) | |
581 | continue; | |
6f610764 | 582 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 583 | list_del_init(&sd->s_sibling); |
6f610764 | 584 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
585 | configfs_drop_dentry(sd, dentry); |
586 | configfs_put(sd); | |
587 | } | |
588 | ||
589 | /** | |
590 | * Drop reference from dget() on entrance. | |
591 | */ | |
592 | dput(dentry); | |
593 | } | |
594 | ||
595 | static int populate_attrs(struct config_item *item) | |
596 | { | |
597 | struct config_item_type *t = item->ci_type; | |
598 | struct configfs_attribute *attr; | |
599 | int error = 0; | |
600 | int i; | |
601 | ||
602 | if (!t) | |
603 | return -EINVAL; | |
604 | if (t->ct_attrs) { | |
605 | for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) { | |
606 | if ((error = configfs_create_file(item, attr))) | |
607 | break; | |
608 | } | |
609 | } | |
610 | ||
611 | if (error) | |
612 | detach_attrs(item); | |
613 | ||
614 | return error; | |
615 | } | |
616 | ||
617 | static int configfs_attach_group(struct config_item *parent_item, | |
618 | struct config_item *item, | |
619 | struct dentry *dentry); | |
620 | static void configfs_detach_group(struct config_item *item); | |
621 | ||
622 | static void detach_groups(struct config_group *group) | |
623 | { | |
624 | struct dentry * dentry = dget(group->cg_item.ci_dentry); | |
625 | struct dentry *child; | |
626 | struct configfs_dirent *parent_sd; | |
627 | struct configfs_dirent *sd, *tmp; | |
628 | ||
629 | if (!dentry) | |
630 | return; | |
631 | ||
632 | parent_sd = dentry->d_fsdata; | |
633 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { | |
634 | if (!sd->s_element || | |
635 | !(sd->s_type & CONFIGFS_USET_DEFAULT)) | |
636 | continue; | |
637 | ||
638 | child = sd->s_dentry; | |
639 | ||
b3e76af8 LR |
640 | mutex_lock(&child->d_inode->i_mutex); |
641 | ||
7063fbf2 JB |
642 | configfs_detach_group(sd->s_element); |
643 | child->d_inode->i_flags |= S_DEAD; | |
d83c49f3 | 644 | dont_mount(child); |
7063fbf2 | 645 | |
b3e76af8 | 646 | mutex_unlock(&child->d_inode->i_mutex); |
7063fbf2 JB |
647 | |
648 | d_delete(child); | |
649 | dput(child); | |
650 | } | |
651 | ||
652 | /** | |
653 | * Drop reference from dget() on entrance. | |
654 | */ | |
655 | dput(dentry); | |
656 | } | |
657 | ||
658 | /* | |
659 | * This fakes mkdir(2) on a default_groups[] entry. It | |
660 | * creates a dentry, attachs it, and then does fixup | |
661 | * on the sd->s_type. | |
662 | * | |
663 | * We could, perhaps, tweak our parent's ->mkdir for a minute and | |
664 | * try using vfs_mkdir. Just a thought. | |
665 | */ | |
666 | static int create_default_group(struct config_group *parent_group, | |
667 | struct config_group *group) | |
668 | { | |
669 | int ret; | |
670 | struct qstr name; | |
671 | struct configfs_dirent *sd; | |
672 | /* We trust the caller holds a reference to parent */ | |
673 | struct dentry *child, *parent = parent_group->cg_item.ci_dentry; | |
674 | ||
675 | if (!group->cg_item.ci_name) | |
676 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
677 | name.name = group->cg_item.ci_name; | |
678 | name.len = strlen(name.name); | |
679 | name.hash = full_name_hash(name.name, name.len); | |
680 | ||
681 | ret = -ENOMEM; | |
682 | child = d_alloc(parent, &name); | |
683 | if (child) { | |
684 | d_add(child, NULL); | |
685 | ||
686 | ret = configfs_attach_group(&parent_group->cg_item, | |
687 | &group->cg_item, child); | |
688 | if (!ret) { | |
689 | sd = child->d_fsdata; | |
690 | sd->s_type |= CONFIGFS_USET_DEFAULT; | |
691 | } else { | |
692 | d_delete(child); | |
693 | dput(child); | |
694 | } | |
695 | } | |
696 | ||
697 | return ret; | |
698 | } | |
699 | ||
700 | static int populate_groups(struct config_group *group) | |
701 | { | |
702 | struct config_group *new_group; | |
7063fbf2 JB |
703 | int ret = 0; |
704 | int i; | |
705 | ||
cbca692c | 706 | if (group->default_groups) { |
7063fbf2 JB |
707 | for (i = 0; group->default_groups[i]; i++) { |
708 | new_group = group->default_groups[i]; | |
709 | ||
710 | ret = create_default_group(group, new_group); | |
2e2ce171 LR |
711 | if (ret) { |
712 | detach_groups(group); | |
7063fbf2 | 713 | break; |
2e2ce171 | 714 | } |
7063fbf2 | 715 | } |
7063fbf2 JB |
716 | } |
717 | ||
7063fbf2 JB |
718 | return ret; |
719 | } | |
720 | ||
721 | /* | |
722 | * All of link_obj/unlink_obj/link_group/unlink_group require that | |
e6bd07ae | 723 | * subsys->su_mutex is held. |
7063fbf2 JB |
724 | */ |
725 | ||
726 | static void unlink_obj(struct config_item *item) | |
727 | { | |
728 | struct config_group *group; | |
729 | ||
730 | group = item->ci_group; | |
731 | if (group) { | |
732 | list_del_init(&item->ci_entry); | |
733 | ||
734 | item->ci_group = NULL; | |
735 | item->ci_parent = NULL; | |
eed7a0db JB |
736 | |
737 | /* Drop the reference for ci_entry */ | |
7063fbf2 JB |
738 | config_item_put(item); |
739 | ||
eed7a0db | 740 | /* Drop the reference for ci_parent */ |
7063fbf2 JB |
741 | config_group_put(group); |
742 | } | |
743 | } | |
744 | ||
745 | static void link_obj(struct config_item *parent_item, struct config_item *item) | |
746 | { | |
eed7a0db JB |
747 | /* |
748 | * Parent seems redundant with group, but it makes certain | |
749 | * traversals much nicer. | |
750 | */ | |
7063fbf2 | 751 | item->ci_parent = parent_item; |
eed7a0db JB |
752 | |
753 | /* | |
754 | * We hold a reference on the parent for the child's ci_parent | |
755 | * link. | |
756 | */ | |
7063fbf2 JB |
757 | item->ci_group = config_group_get(to_config_group(parent_item)); |
758 | list_add_tail(&item->ci_entry, &item->ci_group->cg_children); | |
759 | ||
eed7a0db JB |
760 | /* |
761 | * We hold a reference on the child for ci_entry on the parent's | |
762 | * cg_children | |
763 | */ | |
7063fbf2 JB |
764 | config_item_get(item); |
765 | } | |
766 | ||
767 | static void unlink_group(struct config_group *group) | |
768 | { | |
769 | int i; | |
770 | struct config_group *new_group; | |
771 | ||
772 | if (group->default_groups) { | |
773 | for (i = 0; group->default_groups[i]; i++) { | |
774 | new_group = group->default_groups[i]; | |
775 | unlink_group(new_group); | |
776 | } | |
777 | } | |
778 | ||
779 | group->cg_subsys = NULL; | |
780 | unlink_obj(&group->cg_item); | |
781 | } | |
782 | ||
783 | static void link_group(struct config_group *parent_group, struct config_group *group) | |
784 | { | |
785 | int i; | |
786 | struct config_group *new_group; | |
787 | struct configfs_subsystem *subsys = NULL; /* gcc is a turd */ | |
788 | ||
789 | link_obj(&parent_group->cg_item, &group->cg_item); | |
790 | ||
791 | if (parent_group->cg_subsys) | |
792 | subsys = parent_group->cg_subsys; | |
793 | else if (configfs_is_root(&parent_group->cg_item)) | |
794 | subsys = to_configfs_subsystem(group); | |
795 | else | |
796 | BUG(); | |
797 | group->cg_subsys = subsys; | |
798 | ||
799 | if (group->default_groups) { | |
800 | for (i = 0; group->default_groups[i]; i++) { | |
801 | new_group = group->default_groups[i]; | |
802 | link_group(group, new_group); | |
803 | } | |
804 | } | |
805 | } | |
806 | ||
807 | /* | |
808 | * The goal is that configfs_attach_item() (and | |
809 | * configfs_attach_group()) can be called from either the VFS or this | |
810 | * module. That is, they assume that the items have been created, | |
811 | * the dentry allocated, and the dcache is all ready to go. | |
812 | * | |
813 | * If they fail, they must clean up after themselves as if they | |
814 | * had never been called. The caller (VFS or local function) will | |
815 | * handle cleaning up the dcache bits. | |
816 | * | |
817 | * configfs_detach_group() and configfs_detach_item() behave similarly on | |
818 | * the way out. They assume that the proper semaphores are held, they | |
819 | * clean up the configfs items, and they expect their callers will | |
820 | * handle the dcache bits. | |
821 | */ | |
822 | static int configfs_attach_item(struct config_item *parent_item, | |
823 | struct config_item *item, | |
824 | struct dentry *dentry) | |
825 | { | |
826 | int ret; | |
827 | ||
828 | ret = configfs_create_dir(item, dentry); | |
829 | if (!ret) { | |
830 | ret = populate_attrs(item); | |
831 | if (ret) { | |
2e2ce171 LR |
832 | /* |
833 | * We are going to remove an inode and its dentry but | |
834 | * the VFS may already have hit and used them. Thus, | |
835 | * we must lock them as rmdir() would. | |
836 | */ | |
837 | mutex_lock(&dentry->d_inode->i_mutex); | |
7063fbf2 | 838 | configfs_remove_dir(item); |
2e2ce171 | 839 | dentry->d_inode->i_flags |= S_DEAD; |
d83c49f3 | 840 | dont_mount(dentry); |
2e2ce171 | 841 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
842 | d_delete(dentry); |
843 | } | |
844 | } | |
845 | ||
846 | return ret; | |
847 | } | |
848 | ||
2e2ce171 | 849 | /* Caller holds the mutex of the item's inode */ |
7063fbf2 JB |
850 | static void configfs_detach_item(struct config_item *item) |
851 | { | |
852 | detach_attrs(item); | |
853 | configfs_remove_dir(item); | |
854 | } | |
855 | ||
856 | static int configfs_attach_group(struct config_item *parent_item, | |
857 | struct config_item *item, | |
858 | struct dentry *dentry) | |
859 | { | |
860 | int ret; | |
861 | struct configfs_dirent *sd; | |
862 | ||
863 | ret = configfs_attach_item(parent_item, item, dentry); | |
864 | if (!ret) { | |
865 | sd = dentry->d_fsdata; | |
866 | sd->s_type |= CONFIGFS_USET_DIR; | |
867 | ||
2e2ce171 LR |
868 | /* |
869 | * FYI, we're faking mkdir in populate_groups() | |
870 | * We must lock the group's inode to avoid races with the VFS | |
871 | * which can already hit the inode and try to add/remove entries | |
872 | * under it. | |
873 | * | |
874 | * We must also lock the inode to remove it safely in case of | |
875 | * error, as rmdir() would. | |
876 | */ | |
877 | mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); | |
e74cc06d | 878 | configfs_adjust_dir_dirent_depth_before_populate(sd); |
7063fbf2 JB |
879 | ret = populate_groups(to_config_group(item)); |
880 | if (ret) { | |
881 | configfs_detach_item(item); | |
2e2ce171 | 882 | dentry->d_inode->i_flags |= S_DEAD; |
d83c49f3 | 883 | dont_mount(dentry); |
7063fbf2 | 884 | } |
e74cc06d | 885 | configfs_adjust_dir_dirent_depth_after_populate(sd); |
2e2ce171 LR |
886 | mutex_unlock(&dentry->d_inode->i_mutex); |
887 | if (ret) | |
888 | d_delete(dentry); | |
7063fbf2 JB |
889 | } |
890 | ||
891 | return ret; | |
892 | } | |
893 | ||
2e2ce171 | 894 | /* Caller holds the mutex of the group's inode */ |
7063fbf2 JB |
895 | static void configfs_detach_group(struct config_item *item) |
896 | { | |
897 | detach_groups(to_config_group(item)); | |
898 | configfs_detach_item(item); | |
899 | } | |
900 | ||
299894cc JB |
901 | /* |
902 | * After the item has been detached from the filesystem view, we are | |
903 | * ready to tear it out of the hierarchy. Notify the client before | |
904 | * we do that so they can perform any cleanup that requires | |
905 | * navigating the hierarchy. A client does not need to provide this | |
906 | * callback. The subsystem semaphore MUST be held by the caller, and | |
907 | * references must be valid for both items. It also assumes the | |
908 | * caller has validated ci_type. | |
909 | */ | |
910 | static void client_disconnect_notify(struct config_item *parent_item, | |
911 | struct config_item *item) | |
912 | { | |
913 | struct config_item_type *type; | |
914 | ||
915 | type = parent_item->ci_type; | |
916 | BUG_ON(!type); | |
917 | ||
918 | if (type->ct_group_ops && type->ct_group_ops->disconnect_notify) | |
919 | type->ct_group_ops->disconnect_notify(to_config_group(parent_item), | |
920 | item); | |
921 | } | |
922 | ||
7063fbf2 JB |
923 | /* |
924 | * Drop the initial reference from make_item()/make_group() | |
925 | * This function assumes that reference is held on item | |
926 | * and that item holds a valid reference to the parent. Also, it | |
927 | * assumes the caller has validated ci_type. | |
928 | */ | |
929 | static void client_drop_item(struct config_item *parent_item, | |
930 | struct config_item *item) | |
931 | { | |
932 | struct config_item_type *type; | |
933 | ||
934 | type = parent_item->ci_type; | |
935 | BUG_ON(!type); | |
936 | ||
eed7a0db JB |
937 | /* |
938 | * If ->drop_item() exists, it is responsible for the | |
939 | * config_item_put(). | |
940 | */ | |
7063fbf2 JB |
941 | if (type->ct_group_ops && type->ct_group_ops->drop_item) |
942 | type->ct_group_ops->drop_item(to_config_group(parent_item), | |
299894cc | 943 | item); |
7063fbf2 JB |
944 | else |
945 | config_item_put(item); | |
946 | } | |
947 | ||
631d1feb JB |
948 | #ifdef DEBUG |
949 | static void configfs_dump_one(struct configfs_dirent *sd, int level) | |
950 | { | |
951 | printk(KERN_INFO "%*s\"%s\":\n", level, " ", configfs_get_name(sd)); | |
952 | ||
953 | #define type_print(_type) if (sd->s_type & _type) printk(KERN_INFO "%*s %s\n", level, " ", #_type); | |
954 | type_print(CONFIGFS_ROOT); | |
955 | type_print(CONFIGFS_DIR); | |
956 | type_print(CONFIGFS_ITEM_ATTR); | |
957 | type_print(CONFIGFS_ITEM_LINK); | |
958 | type_print(CONFIGFS_USET_DIR); | |
959 | type_print(CONFIGFS_USET_DEFAULT); | |
960 | type_print(CONFIGFS_USET_DROPPING); | |
961 | #undef type_print | |
962 | } | |
963 | ||
964 | static int configfs_dump(struct configfs_dirent *sd, int level) | |
965 | { | |
966 | struct configfs_dirent *child_sd; | |
967 | int ret = 0; | |
968 | ||
969 | configfs_dump_one(sd, level); | |
970 | ||
971 | if (!(sd->s_type & (CONFIGFS_DIR|CONFIGFS_ROOT))) | |
972 | return 0; | |
973 | ||
974 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) { | |
975 | ret = configfs_dump(child_sd, level + 2); | |
976 | if (ret) | |
977 | break; | |
978 | } | |
979 | ||
980 | return ret; | |
981 | } | |
982 | #endif | |
983 | ||
984 | ||
985 | /* | |
986 | * configfs_depend_item() and configfs_undepend_item() | |
987 | * | |
988 | * WARNING: Do not call these from a configfs callback! | |
989 | * | |
990 | * This describes these functions and their helpers. | |
991 | * | |
992 | * Allow another kernel system to depend on a config_item. If this | |
993 | * happens, the item cannot go away until the dependant can live without | |
994 | * it. The idea is to give client modules as simple an interface as | |
995 | * possible. When a system asks them to depend on an item, they just | |
996 | * call configfs_depend_item(). If the item is live and the client | |
997 | * driver is in good shape, we'll happily do the work for them. | |
998 | * | |
999 | * Why is the locking complex? Because configfs uses the VFS to handle | |
1000 | * all locking, but this function is called outside the normal | |
1001 | * VFS->configfs path. So it must take VFS locks to prevent the | |
1002 | * VFS->configfs stuff (configfs_mkdir(), configfs_rmdir(), etc). This is | |
1003 | * why you can't call these functions underneath configfs callbacks. | |
1004 | * | |
1005 | * Note, btw, that this can be called at *any* time, even when a configfs | |
1006 | * subsystem isn't registered, or when configfs is loading or unloading. | |
1007 | * Just like configfs_register_subsystem(). So we take the same | |
420118ca LR |
1008 | * precautions. We pin the filesystem. We lock configfs_dirent_lock. |
1009 | * If we can find the target item in the | |
631d1feb | 1010 | * configfs tree, it must be part of the subsystem tree as well, so we |
420118ca LR |
1011 | * do not need the subsystem semaphore. Holding configfs_dirent_lock helps |
1012 | * locking out mkdir() and rmdir(), who might be racing us. | |
631d1feb JB |
1013 | */ |
1014 | ||
1015 | /* | |
1016 | * configfs_depend_prep() | |
1017 | * | |
1018 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are | |
1019 | * attributes. This is similar but not the same to configfs_detach_prep(). | |
1020 | * Note that configfs_detach_prep() expects the parent to be locked when it | |
1021 | * is called, but we lock the parent *inside* configfs_depend_prep(). We | |
1022 | * do that so we can unlock it if we find nothing. | |
1023 | * | |
1024 | * Here we do a depth-first search of the dentry hierarchy looking for | |
420118ca LR |
1025 | * our object. |
1026 | * We deliberately ignore items tagged as dropping since they are virtually | |
1027 | * dead, as well as items in the middle of attachment since they virtually | |
1028 | * do not exist yet. This completes the locking out of racing mkdir() and | |
1029 | * rmdir(). | |
1030 | * Note: subdirectories in the middle of attachment start with s_type = | |
1031 | * CONFIGFS_DIR|CONFIGFS_USET_CREATING set by create_dir(). When | |
1032 | * CONFIGFS_USET_CREATING is set, we ignore the item. The actual set of | |
1033 | * s_type is in configfs_new_dirent(), which has configfs_dirent_lock. | |
631d1feb | 1034 | * |
420118ca | 1035 | * If the target is not found, -ENOENT is bubbled up. |
631d1feb JB |
1036 | * |
1037 | * This adds a requirement that all config_items be unique! | |
1038 | * | |
420118ca | 1039 | * This is recursive. There isn't |
631d1feb JB |
1040 | * much on the stack, though, so folks that need this function - be careful |
1041 | * about your stack! Patches will be accepted to make it iterative. | |
1042 | */ | |
1043 | static int configfs_depend_prep(struct dentry *origin, | |
1044 | struct config_item *target) | |
1045 | { | |
1046 | struct configfs_dirent *child_sd, *sd = origin->d_fsdata; | |
1047 | int ret = 0; | |
1048 | ||
1049 | BUG_ON(!origin || !sd); | |
1050 | ||
631d1feb JB |
1051 | if (sd->s_element == target) /* Boo-yah */ |
1052 | goto out; | |
1053 | ||
1054 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) { | |
420118ca LR |
1055 | if ((child_sd->s_type & CONFIGFS_DIR) && |
1056 | !(child_sd->s_type & CONFIGFS_USET_DROPPING) && | |
1057 | !(child_sd->s_type & CONFIGFS_USET_CREATING)) { | |
631d1feb JB |
1058 | ret = configfs_depend_prep(child_sd->s_dentry, |
1059 | target); | |
1060 | if (!ret) | |
1061 | goto out; /* Child path boo-yah */ | |
1062 | } | |
1063 | } | |
1064 | ||
1065 | /* We looped all our children and didn't find target */ | |
631d1feb JB |
1066 | ret = -ENOENT; |
1067 | ||
1068 | out: | |
1069 | return ret; | |
1070 | } | |
1071 | ||
631d1feb JB |
1072 | int configfs_depend_item(struct configfs_subsystem *subsys, |
1073 | struct config_item *target) | |
1074 | { | |
1075 | int ret; | |
1076 | struct configfs_dirent *p, *root_sd, *subsys_sd = NULL; | |
1077 | struct config_item *s_item = &subsys->su_group.cg_item; | |
1078 | ||
1079 | /* | |
1080 | * Pin the configfs filesystem. This means we can safely access | |
1081 | * the root of the configfs filesystem. | |
1082 | */ | |
1083 | ret = configfs_pin_fs(); | |
1084 | if (ret) | |
1085 | return ret; | |
1086 | ||
1087 | /* | |
1088 | * Next, lock the root directory. We're going to check that the | |
1089 | * subsystem is really registered, and so we need to lock out | |
1090 | * configfs_[un]register_subsystem(). | |
1091 | */ | |
1092 | mutex_lock(&configfs_sb->s_root->d_inode->i_mutex); | |
1093 | ||
1094 | root_sd = configfs_sb->s_root->d_fsdata; | |
1095 | ||
1096 | list_for_each_entry(p, &root_sd->s_children, s_sibling) { | |
1097 | if (p->s_type & CONFIGFS_DIR) { | |
1098 | if (p->s_element == s_item) { | |
1099 | subsys_sd = p; | |
1100 | break; | |
1101 | } | |
1102 | } | |
1103 | } | |
1104 | ||
1105 | if (!subsys_sd) { | |
1106 | ret = -ENOENT; | |
1107 | goto out_unlock_fs; | |
1108 | } | |
1109 | ||
1110 | /* Ok, now we can trust subsys/s_item */ | |
1111 | ||
420118ca LR |
1112 | spin_lock(&configfs_dirent_lock); |
1113 | /* Scan the tree, return 0 if found */ | |
631d1feb JB |
1114 | ret = configfs_depend_prep(subsys_sd->s_dentry, target); |
1115 | if (ret) | |
420118ca | 1116 | goto out_unlock_dirent_lock; |
631d1feb | 1117 | |
420118ca LR |
1118 | /* |
1119 | * We are sure that the item is not about to be removed by rmdir(), and | |
1120 | * not in the middle of attachment by mkdir(). | |
1121 | */ | |
631d1feb JB |
1122 | p = target->ci_dentry->d_fsdata; |
1123 | p->s_dependent_count += 1; | |
1124 | ||
420118ca LR |
1125 | out_unlock_dirent_lock: |
1126 | spin_unlock(&configfs_dirent_lock); | |
631d1feb JB |
1127 | out_unlock_fs: |
1128 | mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex); | |
1129 | ||
1130 | /* | |
1131 | * If we succeeded, the fs is pinned via other methods. If not, | |
1132 | * we're done with it anyway. So release_fs() is always right. | |
1133 | */ | |
1134 | configfs_release_fs(); | |
1135 | ||
1136 | return ret; | |
1137 | } | |
1138 | EXPORT_SYMBOL(configfs_depend_item); | |
1139 | ||
1140 | /* | |
1141 | * Release the dependent linkage. This is much simpler than | |
1142 | * configfs_depend_item() because we know that that the client driver is | |
1143 | * pinned, thus the subsystem is pinned, and therefore configfs is pinned. | |
1144 | */ | |
1145 | void configfs_undepend_item(struct configfs_subsystem *subsys, | |
1146 | struct config_item *target) | |
1147 | { | |
1148 | struct configfs_dirent *sd; | |
1149 | ||
1150 | /* | |
420118ca LR |
1151 | * Since we can trust everything is pinned, we just need |
1152 | * configfs_dirent_lock. | |
631d1feb | 1153 | */ |
420118ca | 1154 | spin_lock(&configfs_dirent_lock); |
631d1feb JB |
1155 | |
1156 | sd = target->ci_dentry->d_fsdata; | |
1157 | BUG_ON(sd->s_dependent_count < 1); | |
1158 | ||
1159 | sd->s_dependent_count -= 1; | |
1160 | ||
1161 | /* | |
1162 | * After this unlock, we cannot trust the item to stay alive! | |
1163 | * DO NOT REFERENCE item after this unlock. | |
1164 | */ | |
420118ca | 1165 | spin_unlock(&configfs_dirent_lock); |
631d1feb JB |
1166 | } |
1167 | EXPORT_SYMBOL(configfs_undepend_item); | |
7063fbf2 JB |
1168 | |
1169 | static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
1170 | { | |
a6795e9e JB |
1171 | int ret = 0; |
1172 | int module_got = 0; | |
1173 | struct config_group *group = NULL; | |
1174 | struct config_item *item = NULL; | |
7063fbf2 JB |
1175 | struct config_item *parent_item; |
1176 | struct configfs_subsystem *subsys; | |
1177 | struct configfs_dirent *sd; | |
1178 | struct config_item_type *type; | |
70526b67 | 1179 | struct module *subsys_owner = NULL, *new_item_owner = NULL; |
7063fbf2 JB |
1180 | char *name; |
1181 | ||
84efad1a JB |
1182 | if (dentry->d_parent == configfs_sb->s_root) { |
1183 | ret = -EPERM; | |
1184 | goto out; | |
1185 | } | |
7063fbf2 JB |
1186 | |
1187 | sd = dentry->d_parent->d_fsdata; | |
2a109f2a LR |
1188 | |
1189 | /* | |
1190 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
1191 | * being attached | |
1192 | */ | |
1193 | if (!configfs_dirent_is_ready(sd)) { | |
1194 | ret = -ENOENT; | |
1195 | goto out; | |
1196 | } | |
1197 | ||
84efad1a JB |
1198 | if (!(sd->s_type & CONFIGFS_USET_DIR)) { |
1199 | ret = -EPERM; | |
1200 | goto out; | |
1201 | } | |
7063fbf2 | 1202 | |
84efad1a | 1203 | /* Get a working ref for the duration of this function */ |
7063fbf2 JB |
1204 | parent_item = configfs_get_config_item(dentry->d_parent); |
1205 | type = parent_item->ci_type; | |
1206 | subsys = to_config_group(parent_item)->cg_subsys; | |
1207 | BUG_ON(!subsys); | |
1208 | ||
1209 | if (!type || !type->ct_group_ops || | |
1210 | (!type->ct_group_ops->make_group && | |
1211 | !type->ct_group_ops->make_item)) { | |
84efad1a JB |
1212 | ret = -EPERM; /* Lack-of-mkdir returns -EPERM */ |
1213 | goto out_put; | |
7063fbf2 JB |
1214 | } |
1215 | ||
70526b67 JB |
1216 | /* |
1217 | * The subsystem may belong to a different module than the item | |
1218 | * being created. We don't want to safely pin the new item but | |
1219 | * fail to pin the subsystem it sits under. | |
1220 | */ | |
1221 | if (!subsys->su_group.cg_item.ci_type) { | |
1222 | ret = -EINVAL; | |
1223 | goto out_put; | |
1224 | } | |
1225 | subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; | |
1226 | if (!try_module_get(subsys_owner)) { | |
1227 | ret = -EINVAL; | |
1228 | goto out_put; | |
1229 | } | |
1230 | ||
7063fbf2 JB |
1231 | name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL); |
1232 | if (!name) { | |
84efad1a | 1233 | ret = -ENOMEM; |
70526b67 | 1234 | goto out_subsys_put; |
7063fbf2 | 1235 | } |
84efad1a | 1236 | |
7063fbf2 JB |
1237 | snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name); |
1238 | ||
e6bd07ae | 1239 | mutex_lock(&subsys->su_mutex); |
7063fbf2 | 1240 | if (type->ct_group_ops->make_group) { |
f89ab861 | 1241 | group = type->ct_group_ops->make_group(to_config_group(parent_item), name); |
a6795e9e JB |
1242 | if (!group) |
1243 | group = ERR_PTR(-ENOMEM); | |
1244 | if (!IS_ERR(group)) { | |
7063fbf2 JB |
1245 | link_group(to_config_group(parent_item), group); |
1246 | item = &group->cg_item; | |
a6795e9e JB |
1247 | } else |
1248 | ret = PTR_ERR(group); | |
7063fbf2 | 1249 | } else { |
f89ab861 | 1250 | item = type->ct_group_ops->make_item(to_config_group(parent_item), name); |
a6795e9e JB |
1251 | if (!item) |
1252 | item = ERR_PTR(-ENOMEM); | |
1253 | if (!IS_ERR(item)) | |
7063fbf2 | 1254 | link_obj(parent_item, item); |
a6795e9e JB |
1255 | else |
1256 | ret = PTR_ERR(item); | |
7063fbf2 | 1257 | } |
e6bd07ae | 1258 | mutex_unlock(&subsys->su_mutex); |
7063fbf2 JB |
1259 | |
1260 | kfree(name); | |
a6795e9e | 1261 | if (ret) { |
eed7a0db | 1262 | /* |
dacdd0e0 | 1263 | * If ret != 0, then link_obj() was never called. |
eed7a0db JB |
1264 | * There are no extra references to clean up. |
1265 | */ | |
70526b67 | 1266 | goto out_subsys_put; |
7063fbf2 JB |
1267 | } |
1268 | ||
eed7a0db JB |
1269 | /* |
1270 | * link_obj() has been called (via link_group() for groups). | |
1271 | * From here on out, errors must clean that up. | |
1272 | */ | |
1273 | ||
7063fbf2 | 1274 | type = item->ci_type; |
eed7a0db JB |
1275 | if (!type) { |
1276 | ret = -EINVAL; | |
1277 | goto out_unlink; | |
1278 | } | |
7063fbf2 | 1279 | |
70526b67 JB |
1280 | new_item_owner = type->ct_owner; |
1281 | if (!try_module_get(new_item_owner)) { | |
eed7a0db JB |
1282 | ret = -EINVAL; |
1283 | goto out_unlink; | |
1284 | } | |
7063fbf2 | 1285 | |
eed7a0db JB |
1286 | /* |
1287 | * I hate doing it this way, but if there is | |
1288 | * an error, module_put() probably should | |
1289 | * happen after any cleanup. | |
1290 | */ | |
1291 | module_got = 1; | |
1292 | ||
6d8344ba LR |
1293 | /* |
1294 | * Make racing rmdir() fail if it did not tag parent with | |
1295 | * CONFIGFS_USET_DROPPING | |
1296 | * Note: if CONFIGFS_USET_DROPPING is already set, attach_group() will | |
1297 | * fail and let rmdir() terminate correctly | |
1298 | */ | |
1299 | spin_lock(&configfs_dirent_lock); | |
1300 | /* This will make configfs_detach_prep() fail */ | |
1301 | sd->s_type |= CONFIGFS_USET_IN_MKDIR; | |
1302 | spin_unlock(&configfs_dirent_lock); | |
1303 | ||
eed7a0db JB |
1304 | if (group) |
1305 | ret = configfs_attach_group(parent_item, item, dentry); | |
1306 | else | |
1307 | ret = configfs_attach_item(parent_item, item, dentry); | |
1308 | ||
6d8344ba LR |
1309 | spin_lock(&configfs_dirent_lock); |
1310 | sd->s_type &= ~CONFIGFS_USET_IN_MKDIR; | |
2a109f2a LR |
1311 | if (!ret) |
1312 | configfs_dir_set_ready(dentry->d_fsdata); | |
6d8344ba LR |
1313 | spin_unlock(&configfs_dirent_lock); |
1314 | ||
eed7a0db JB |
1315 | out_unlink: |
1316 | if (ret) { | |
1317 | /* Tear down everything we built up */ | |
e6bd07ae | 1318 | mutex_lock(&subsys->su_mutex); |
299894cc JB |
1319 | |
1320 | client_disconnect_notify(parent_item, item); | |
eed7a0db JB |
1321 | if (group) |
1322 | unlink_group(group); | |
1323 | else | |
1324 | unlink_obj(item); | |
1325 | client_drop_item(parent_item, item); | |
299894cc | 1326 | |
e6bd07ae | 1327 | mutex_unlock(&subsys->su_mutex); |
eed7a0db JB |
1328 | |
1329 | if (module_got) | |
70526b67 | 1330 | module_put(new_item_owner); |
7063fbf2 JB |
1331 | } |
1332 | ||
70526b67 JB |
1333 | out_subsys_put: |
1334 | if (ret) | |
1335 | module_put(subsys_owner); | |
1336 | ||
84efad1a JB |
1337 | out_put: |
1338 | /* | |
eed7a0db JB |
1339 | * link_obj()/link_group() took a reference from child->parent, |
1340 | * so the parent is safely pinned. We can drop our working | |
1341 | * reference. | |
84efad1a JB |
1342 | */ |
1343 | config_item_put(parent_item); | |
1344 | ||
1345 | out: | |
7063fbf2 JB |
1346 | return ret; |
1347 | } | |
1348 | ||
1349 | static int configfs_rmdir(struct inode *dir, struct dentry *dentry) | |
1350 | { | |
1351 | struct config_item *parent_item; | |
1352 | struct config_item *item; | |
1353 | struct configfs_subsystem *subsys; | |
1354 | struct configfs_dirent *sd; | |
70526b67 | 1355 | struct module *subsys_owner = NULL, *dead_item_owner = NULL; |
7063fbf2 JB |
1356 | int ret; |
1357 | ||
1358 | if (dentry->d_parent == configfs_sb->s_root) | |
1359 | return -EPERM; | |
1360 | ||
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 | ||
1458 | #if 0 | |
1459 | int configfs_rename_dir(struct config_item * item, const char *new_name) | |
1460 | { | |
1461 | int error = 0; | |
1462 | struct dentry * new_dentry, * parent; | |
1463 | ||
1464 | if (!strcmp(config_item_name(item), new_name)) | |
1465 | return -EINVAL; | |
1466 | ||
1467 | if (!item->parent) | |
1468 | return -EINVAL; | |
1469 | ||
1470 | down_write(&configfs_rename_sem); | |
1471 | parent = item->parent->dentry; | |
1472 | ||
1b1dcc1b | 1473 | mutex_lock(&parent->d_inode->i_mutex); |
7063fbf2 JB |
1474 | |
1475 | new_dentry = lookup_one_len(new_name, parent, strlen(new_name)); | |
1476 | if (!IS_ERR(new_dentry)) { | |
e7515d06 | 1477 | if (!new_dentry->d_inode) { |
7063fbf2 JB |
1478 | error = config_item_set_name(item, "%s", new_name); |
1479 | if (!error) { | |
1480 | d_add(new_dentry, NULL); | |
1481 | d_move(item->dentry, new_dentry); | |
1482 | } | |
1483 | else | |
1484 | d_delete(new_dentry); | |
1485 | } else | |
1486 | error = -EEXIST; | |
1487 | dput(new_dentry); | |
1488 | } | |
1b1dcc1b | 1489 | mutex_unlock(&parent->d_inode->i_mutex); |
7063fbf2 JB |
1490 | up_write(&configfs_rename_sem); |
1491 | ||
1492 | return error; | |
1493 | } | |
1494 | #endif | |
1495 | ||
1496 | static int configfs_dir_open(struct inode *inode, struct file *file) | |
1497 | { | |
867fa491 | 1498 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 | 1499 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
2a109f2a | 1500 | int err; |
7063fbf2 | 1501 | |
1b1dcc1b | 1502 | mutex_lock(&dentry->d_inode->i_mutex); |
2a109f2a LR |
1503 | /* |
1504 | * Fake invisibility if dir belongs to a group/default groups hierarchy | |
1505 | * being attached | |
1506 | */ | |
1507 | err = -ENOENT; | |
1508 | if (configfs_dirent_is_ready(parent_sd)) { | |
420118ca | 1509 | file->private_data = configfs_new_dirent(parent_sd, NULL, 0); |
2a109f2a LR |
1510 | if (IS_ERR(file->private_data)) |
1511 | err = PTR_ERR(file->private_data); | |
1512 | else | |
1513 | err = 0; | |
1514 | } | |
1b1dcc1b | 1515 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 | 1516 | |
2a109f2a | 1517 | return err; |
7063fbf2 JB |
1518 | } |
1519 | ||
1520 | static int configfs_dir_close(struct inode *inode, struct file *file) | |
1521 | { | |
867fa491 | 1522 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 JB |
1523 | struct configfs_dirent * cursor = file->private_data; |
1524 | ||
1b1dcc1b | 1525 | mutex_lock(&dentry->d_inode->i_mutex); |
6f610764 | 1526 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 1527 | list_del_init(&cursor->s_sibling); |
6f610764 | 1528 | spin_unlock(&configfs_dirent_lock); |
1b1dcc1b | 1529 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1530 | |
1531 | release_configfs_dirent(cursor); | |
1532 | ||
1533 | return 0; | |
1534 | } | |
1535 | ||
1536 | /* Relationship between s_mode and the DT_xxx types */ | |
1537 | static inline unsigned char dt_type(struct configfs_dirent *sd) | |
1538 | { | |
1539 | return (sd->s_mode >> 12) & 15; | |
1540 | } | |
1541 | ||
1542 | static int configfs_readdir(struct file * filp, void * dirent, filldir_t filldir) | |
1543 | { | |
867fa491 | 1544 | struct dentry *dentry = filp->f_path.dentry; |
7063fbf2 JB |
1545 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
1546 | struct configfs_dirent *cursor = filp->private_data; | |
1547 | struct list_head *p, *q = &cursor->s_sibling; | |
1548 | ino_t ino; | |
1549 | int i = filp->f_pos; | |
1550 | ||
1551 | switch (i) { | |
1552 | case 0: | |
1553 | ino = dentry->d_inode->i_ino; | |
1554 | if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) | |
1555 | break; | |
1556 | filp->f_pos++; | |
1557 | i++; | |
1558 | /* fallthrough */ | |
1559 | case 1: | |
1560 | ino = parent_ino(dentry); | |
1561 | if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) | |
1562 | break; | |
1563 | filp->f_pos++; | |
1564 | i++; | |
1565 | /* fallthrough */ | |
1566 | default: | |
1567 | if (filp->f_pos == 2) { | |
6f610764 | 1568 | spin_lock(&configfs_dirent_lock); |
f116629d | 1569 | list_move(q, &parent_sd->s_children); |
6f610764 | 1570 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
1571 | } |
1572 | for (p=q->next; p!= &parent_sd->s_children; p=p->next) { | |
1573 | struct configfs_dirent *next; | |
1574 | const char * name; | |
1575 | int len; | |
1576 | ||
1577 | next = list_entry(p, struct configfs_dirent, | |
1578 | s_sibling); | |
1579 | if (!next->s_element) | |
1580 | continue; | |
1581 | ||
1582 | name = configfs_get_name(next); | |
1583 | len = strlen(name); | |
1584 | if (next->s_dentry) | |
1585 | ino = next->s_dentry->d_inode->i_ino; | |
1586 | else | |
1587 | ino = iunique(configfs_sb, 2); | |
1588 | ||
1589 | if (filldir(dirent, name, len, filp->f_pos, ino, | |
1590 | dt_type(next)) < 0) | |
1591 | return 0; | |
1592 | ||
6f610764 | 1593 | spin_lock(&configfs_dirent_lock); |
f116629d | 1594 | list_move(q, p); |
6f610764 | 1595 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
1596 | p = q; |
1597 | filp->f_pos++; | |
1598 | } | |
1599 | } | |
1600 | return 0; | |
1601 | } | |
1602 | ||
1603 | static loff_t configfs_dir_lseek(struct file * file, loff_t offset, int origin) | |
1604 | { | |
867fa491 | 1605 | struct dentry * dentry = file->f_path.dentry; |
7063fbf2 | 1606 | |
1b1dcc1b | 1607 | mutex_lock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1608 | switch (origin) { |
1609 | case 1: | |
1610 | offset += file->f_pos; | |
1611 | case 0: | |
1612 | if (offset >= 0) | |
1613 | break; | |
1614 | default: | |
867fa491 | 1615 | mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); |
7063fbf2 JB |
1616 | return -EINVAL; |
1617 | } | |
1618 | if (offset != file->f_pos) { | |
1619 | file->f_pos = offset; | |
1620 | if (file->f_pos >= 2) { | |
1621 | struct configfs_dirent *sd = dentry->d_fsdata; | |
1622 | struct configfs_dirent *cursor = file->private_data; | |
1623 | struct list_head *p; | |
1624 | loff_t n = file->f_pos - 2; | |
1625 | ||
6f610764 | 1626 | spin_lock(&configfs_dirent_lock); |
7063fbf2 JB |
1627 | list_del(&cursor->s_sibling); |
1628 | p = sd->s_children.next; | |
1629 | while (n && p != &sd->s_children) { | |
1630 | struct configfs_dirent *next; | |
1631 | next = list_entry(p, struct configfs_dirent, | |
1632 | s_sibling); | |
1633 | if (next->s_element) | |
1634 | n--; | |
1635 | p = p->next; | |
1636 | } | |
1637 | list_add_tail(&cursor->s_sibling, p); | |
6f610764 | 1638 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
1639 | } |
1640 | } | |
1b1dcc1b | 1641 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1642 | return offset; |
1643 | } | |
1644 | ||
4b6f5d20 | 1645 | const struct file_operations configfs_dir_operations = { |
7063fbf2 JB |
1646 | .open = configfs_dir_open, |
1647 | .release = configfs_dir_close, | |
1648 | .llseek = configfs_dir_lseek, | |
1649 | .read = generic_read_dir, | |
1650 | .readdir = configfs_readdir, | |
1651 | }; | |
1652 | ||
1653 | int configfs_register_subsystem(struct configfs_subsystem *subsys) | |
1654 | { | |
1655 | int err; | |
1656 | struct config_group *group = &subsys->su_group; | |
1657 | struct qstr name; | |
1658 | struct dentry *dentry; | |
1659 | struct configfs_dirent *sd; | |
1660 | ||
1661 | err = configfs_pin_fs(); | |
1662 | if (err) | |
1663 | return err; | |
1664 | ||
1665 | if (!group->cg_item.ci_name) | |
1666 | group->cg_item.ci_name = group->cg_item.ci_namebuf; | |
1667 | ||
1668 | sd = configfs_sb->s_root->d_fsdata; | |
1669 | link_group(to_config_group(sd->s_element), group); | |
1670 | ||
ba611edf JP |
1671 | mutex_lock_nested(&configfs_sb->s_root->d_inode->i_mutex, |
1672 | I_MUTEX_PARENT); | |
7063fbf2 JB |
1673 | |
1674 | name.name = group->cg_item.ci_name; | |
1675 | name.len = strlen(name.name); | |
1676 | name.hash = full_name_hash(name.name, name.len); | |
1677 | ||
1678 | err = -ENOMEM; | |
1679 | dentry = d_alloc(configfs_sb->s_root, &name); | |
afdf04ea JB |
1680 | if (dentry) { |
1681 | d_add(dentry, NULL); | |
7063fbf2 | 1682 | |
afdf04ea JB |
1683 | err = configfs_attach_group(sd->s_element, &group->cg_item, |
1684 | dentry); | |
1685 | if (err) { | |
1686 | d_delete(dentry); | |
1687 | dput(dentry); | |
2a109f2a LR |
1688 | } else { |
1689 | spin_lock(&configfs_dirent_lock); | |
1690 | configfs_dir_set_ready(dentry->d_fsdata); | |
1691 | spin_unlock(&configfs_dirent_lock); | |
afdf04ea JB |
1692 | } |
1693 | } | |
7063fbf2 | 1694 | |
1b1dcc1b | 1695 | mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex); |
7063fbf2 | 1696 | |
afdf04ea JB |
1697 | if (err) { |
1698 | unlink_group(group); | |
1699 | configfs_release_fs(); | |
7063fbf2 JB |
1700 | } |
1701 | ||
1702 | return err; | |
1703 | } | |
1704 | ||
1705 | void configfs_unregister_subsystem(struct configfs_subsystem *subsys) | |
1706 | { | |
1707 | struct config_group *group = &subsys->su_group; | |
1708 | struct dentry *dentry = group->cg_item.ci_dentry; | |
1709 | ||
1710 | if (dentry->d_parent != configfs_sb->s_root) { | |
1711 | printk(KERN_ERR "configfs: Tried to unregister non-subsystem!\n"); | |
1712 | return; | |
1713 | } | |
1714 | ||
55ed1602 MF |
1715 | mutex_lock_nested(&configfs_sb->s_root->d_inode->i_mutex, |
1716 | I_MUTEX_PARENT); | |
1717 | mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); | |
9a73d78c | 1718 | mutex_lock(&configfs_symlink_mutex); |
b3e76af8 | 1719 | spin_lock(&configfs_dirent_lock); |
6d8344ba | 1720 | if (configfs_detach_prep(dentry, NULL)) { |
7063fbf2 JB |
1721 | printk(KERN_ERR "configfs: Tried to unregister non-empty subsystem!\n"); |
1722 | } | |
b3e76af8 | 1723 | spin_unlock(&configfs_dirent_lock); |
9a73d78c | 1724 | mutex_unlock(&configfs_symlink_mutex); |
7063fbf2 JB |
1725 | configfs_detach_group(&group->cg_item); |
1726 | dentry->d_inode->i_flags |= S_DEAD; | |
d83c49f3 | 1727 | dont_mount(dentry); |
1b1dcc1b | 1728 | mutex_unlock(&dentry->d_inode->i_mutex); |
7063fbf2 JB |
1729 | |
1730 | d_delete(dentry); | |
1731 | ||
1b1dcc1b | 1732 | mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex); |
7063fbf2 JB |
1733 | |
1734 | dput(dentry); | |
1735 | ||
1736 | unlink_group(group); | |
1737 | configfs_release_fs(); | |
1738 | } | |
1739 | ||
1740 | EXPORT_SYMBOL(configfs_register_subsystem); | |
1741 | EXPORT_SYMBOL(configfs_unregister_subsystem); |