Root/
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> |
33 | #include <linux/err.h> |
34 | |
35 | #include <linux/configfs.h> |
36 | #include "configfs_internal.h" |
37 | |
38 | DECLARE_RWSEM(configfs_rename_sem); |
39 | /* |
40 | * Protects mutations of configfs_dirent linkage together with proper i_mutex |
41 | * Also protects mutations of symlinks linkage to target configfs_dirent |
42 | * Mutators of configfs_dirent linkage must *both* have the proper inode locked |
43 | * and configfs_dirent_lock locked, in that order. |
44 | * This allows one to safely traverse configfs_dirent trees and symlinks without |
45 | * having to lock inodes. |
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() |
50 | */ |
51 | DEFINE_SPINLOCK(configfs_dirent_lock); |
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 | */ |
70 | static int configfs_d_delete(struct dentry *dentry) |
71 | { |
72 | return 1; |
73 | } |
74 | |
75 | static const struct dentry_operations configfs_dentry_ops = { |
76 | .d_iput = configfs_d_iput, |
77 | /* simple_delete_dentry() isn't exported */ |
78 | .d_delete = configfs_d_delete, |
79 | }; |
80 | |
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 | |
167 | /* |
168 | * Allocates a new configfs_dirent and links it to the parent configfs_dirent |
169 | */ |
170 | static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *parent_sd, |
171 | void *element, int type) |
172 | { |
173 | struct configfs_dirent * sd; |
174 | |
175 | sd = kmem_cache_zalloc(configfs_dir_cachep, GFP_KERNEL); |
176 | if (!sd) |
177 | return ERR_PTR(-ENOMEM); |
178 | |
179 | atomic_set(&sd->s_count, 1); |
180 | INIT_LIST_HEAD(&sd->s_links); |
181 | INIT_LIST_HEAD(&sd->s_children); |
182 | sd->s_element = element; |
183 | sd->s_type = type; |
184 | configfs_init_dirent_depth(sd); |
185 | spin_lock(&configfs_dirent_lock); |
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 | } |
191 | list_add(&sd->s_sibling, &parent_sd->s_children); |
192 | spin_unlock(&configfs_dirent_lock); |
193 | |
194 | return sd; |
195 | } |
196 | |
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 | */ |
204 | static int configfs_dirent_exists(struct configfs_dirent *parent_sd, |
205 | const unsigned char *new) |
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 | |
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 | |
229 | sd = configfs_new_dirent(parent_sd, element, type); |
230 | if (IS_ERR(sd)) |
231 | return PTR_ERR(sd); |
232 | |
233 | sd->s_mode = mode; |
234 | sd->s_dentry = dentry; |
235 | if (dentry) { |
236 | dentry->d_fsdata = configfs_get(sd); |
237 | dentry->d_op = &configfs_dentry_ops; |
238 | } |
239 | |
240 | return 0; |
241 | } |
242 | |
243 | static int init_dir(struct inode * inode) |
244 | { |
245 | inode->i_op = &configfs_dir_inode_operations; |
246 | inode->i_fop = &configfs_dir_operations; |
247 | |
248 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ |
249 | inc_nlink(inode); |
250 | return 0; |
251 | } |
252 | |
253 | static int configfs_init_file(struct inode * inode) |
254 | { |
255 | inode->i_size = PAGE_SIZE; |
256 | inode->i_fop = &configfs_file_operations; |
257 | return 0; |
258 | } |
259 | |
260 | static int init_symlink(struct inode * inode) |
261 | { |
262 | inode->i_op = &configfs_symlink_inode_operations; |
263 | return 0; |
264 | } |
265 | |
266 | static int create_dir(struct config_item * k, struct dentry * p, |
267 | struct dentry * d) |
268 | { |
269 | int error; |
270 | umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO; |
271 | |
272 | error = configfs_dirent_exists(p->d_fsdata, d->d_name.name); |
273 | if (!error) |
274 | error = configfs_make_dirent(p->d_fsdata, d, k, mode, |
275 | CONFIGFS_DIR | CONFIGFS_USET_CREATING); |
276 | if (!error) { |
277 | configfs_set_dir_dirent_depth(p->d_fsdata, d->d_fsdata); |
278 | error = configfs_create(d, mode, init_dir); |
279 | if (!error) { |
280 | inc_nlink(p->d_inode); |
281 | (d)->d_op = &configfs_dentry_ops; |
282 | } else { |
283 | struct configfs_dirent *sd = d->d_fsdata; |
284 | if (sd) { |
285 | spin_lock(&configfs_dirent_lock); |
286 | list_del_init(&sd->s_sibling); |
287 | spin_unlock(&configfs_dirent_lock); |
288 | configfs_put(sd); |
289 | } |
290 | } |
291 | } |
292 | return error; |
293 | } |
294 | |
295 | |
296 | /** |
297 | * configfs_create_dir - create a directory for an config_item. |
298 | * @item: config_itemwe're creating directory for. |
299 | * @dentry: config_item's dentry. |
300 | * |
301 | * Note: user-created entries won't be allowed under this new directory |
302 | * until it is validated by configfs_dir_set_ready() |
303 | */ |
304 | |
305 | static int configfs_create_dir(struct config_item * item, struct dentry *dentry) |
306 | { |
307 | struct dentry * parent; |
308 | int error = 0; |
309 | |
310 | BUG_ON(!item); |
311 | |
312 | if (item->ci_parent) |
313 | parent = item->ci_parent->ci_dentry; |
314 | else if (configfs_mount && configfs_mount->mnt_sb) |
315 | parent = configfs_mount->mnt_sb->s_root; |
316 | else |
317 | return -EFAULT; |
318 | |
319 | error = create_dir(item,parent,dentry); |
320 | if (!error) |
321 | item->ci_dentry = dentry; |
322 | return error; |
323 | } |
324 | |
325 | /* |
326 | * Allow userspace to create new entries under a new directory created with |
327 | * configfs_create_dir(), and under all of its chidlren directories recursively. |
328 | * @sd configfs_dirent of the new directory to validate |
329 | * |
330 | * Caller must hold configfs_dirent_lock. |
331 | */ |
332 | static void configfs_dir_set_ready(struct configfs_dirent *sd) |
333 | { |
334 | struct configfs_dirent *child_sd; |
335 | |
336 | sd->s_type &= ~CONFIGFS_USET_CREATING; |
337 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) |
338 | if (child_sd->s_type & CONFIGFS_USET_CREATING) |
339 | configfs_dir_set_ready(child_sd); |
340 | } |
341 | |
342 | /* |
343 | * Check that a directory does not belong to a directory hierarchy being |
344 | * attached and not validated yet. |
345 | * @sd configfs_dirent of the directory to check |
346 | * |
347 | * @return non-zero iff the directory was validated |
348 | * |
349 | * Note: takes configfs_dirent_lock, so the result may change from false to true |
350 | * in two consecutive calls, but never from true to false. |
351 | */ |
352 | int configfs_dirent_is_ready(struct configfs_dirent *sd) |
353 | { |
354 | int ret; |
355 | |
356 | spin_lock(&configfs_dirent_lock); |
357 | ret = !(sd->s_type & CONFIGFS_USET_CREATING); |
358 | spin_unlock(&configfs_dirent_lock); |
359 | |
360 | return ret; |
361 | } |
362 | |
363 | int configfs_create_link(struct configfs_symlink *sl, |
364 | struct dentry *parent, |
365 | struct dentry *dentry) |
366 | { |
367 | int err = 0; |
368 | umode_t mode = S_IFLNK | S_IRWXUGO; |
369 | |
370 | err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode, |
371 | CONFIGFS_ITEM_LINK); |
372 | if (!err) { |
373 | err = configfs_create(dentry, mode, init_symlink); |
374 | if (!err) |
375 | dentry->d_op = &configfs_dentry_ops; |
376 | else { |
377 | struct configfs_dirent *sd = dentry->d_fsdata; |
378 | if (sd) { |
379 | spin_lock(&configfs_dirent_lock); |
380 | list_del_init(&sd->s_sibling); |
381 | spin_unlock(&configfs_dirent_lock); |
382 | configfs_put(sd); |
383 | } |
384 | } |
385 | } |
386 | return err; |
387 | } |
388 | |
389 | static void remove_dir(struct dentry * d) |
390 | { |
391 | struct dentry * parent = dget(d->d_parent); |
392 | struct configfs_dirent * sd; |
393 | |
394 | sd = d->d_fsdata; |
395 | spin_lock(&configfs_dirent_lock); |
396 | list_del_init(&sd->s_sibling); |
397 | spin_unlock(&configfs_dirent_lock); |
398 | configfs_put(sd); |
399 | if (d->d_inode) |
400 | simple_rmdir(parent->d_inode,d); |
401 | |
402 | pr_debug(" o %s removing done (%d)\n",d->d_name.name, |
403 | atomic_read(&d->d_count)); |
404 | |
405 | dput(parent); |
406 | } |
407 | |
408 | /** |
409 | * configfs_remove_dir - remove an config_item's directory. |
410 | * @item: config_item we're removing. |
411 | * |
412 | * The only thing special about this is that we remove any files in |
413 | * the directory before we remove the directory, and we've inlined |
414 | * what used to be configfs_rmdir() below, instead of calling separately. |
415 | * |
416 | * Caller holds the mutex of the item's inode |
417 | */ |
418 | |
419 | static void configfs_remove_dir(struct config_item * item) |
420 | { |
421 | struct dentry * dentry = dget(item->ci_dentry); |
422 | |
423 | if (!dentry) |
424 | return; |
425 | |
426 | remove_dir(dentry); |
427 | /** |
428 | * Drop reference from dget() on entrance. |
429 | */ |
430 | dput(dentry); |
431 | } |
432 | |
433 | |
434 | /* attaches attribute's configfs_dirent to the dentry corresponding to the |
435 | * attribute file |
436 | */ |
437 | static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry) |
438 | { |
439 | struct configfs_attribute * attr = sd->s_element; |
440 | int error; |
441 | |
442 | dentry->d_fsdata = configfs_get(sd); |
443 | sd->s_dentry = dentry; |
444 | error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG, |
445 | configfs_init_file); |
446 | if (error) { |
447 | configfs_put(sd); |
448 | return error; |
449 | } |
450 | |
451 | dentry->d_op = &configfs_dentry_ops; |
452 | d_rehash(dentry); |
453 | |
454 | return 0; |
455 | } |
456 | |
457 | static struct dentry * configfs_lookup(struct inode *dir, |
458 | struct dentry *dentry, |
459 | struct nameidata *nd) |
460 | { |
461 | struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata; |
462 | struct configfs_dirent * sd; |
463 | int found = 0; |
464 | int err; |
465 | |
466 | /* |
467 | * Fake invisibility if dir belongs to a group/default groups hierarchy |
468 | * being attached |
469 | * |
470 | * This forbids userspace to read/write attributes of items which may |
471 | * not complete their initialization, since the dentries of the |
472 | * attributes won't be instantiated. |
473 | */ |
474 | err = -ENOENT; |
475 | if (!configfs_dirent_is_ready(parent_sd)) |
476 | goto out; |
477 | |
478 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { |
479 | if (sd->s_type & CONFIGFS_NOT_PINNED) { |
480 | const unsigned char * name = configfs_get_name(sd); |
481 | |
482 | if (strcmp(name, dentry->d_name.name)) |
483 | continue; |
484 | |
485 | found = 1; |
486 | err = configfs_attach_attr(sd, dentry); |
487 | break; |
488 | } |
489 | } |
490 | |
491 | if (!found) { |
492 | /* |
493 | * If it doesn't exist and it isn't a NOT_PINNED item, |
494 | * it must be negative. |
495 | */ |
496 | return simple_lookup(dir, dentry, nd); |
497 | } |
498 | |
499 | out: |
500 | return ERR_PTR(err); |
501 | } |
502 | |
503 | /* |
504 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are |
505 | * attributes and are removed by rmdir(). We recurse, setting |
506 | * CONFIGFS_USET_DROPPING on all children that are candidates for |
507 | * default detach. |
508 | * If there is an error, the caller will reset the flags via |
509 | * configfs_detach_rollback(). |
510 | */ |
511 | static int configfs_detach_prep(struct dentry *dentry, struct mutex **wait_mutex) |
512 | { |
513 | struct configfs_dirent *parent_sd = dentry->d_fsdata; |
514 | struct configfs_dirent *sd; |
515 | int ret; |
516 | |
517 | /* Mark that we're trying to drop the group */ |
518 | parent_sd->s_type |= CONFIGFS_USET_DROPPING; |
519 | |
520 | ret = -EBUSY; |
521 | if (!list_empty(&parent_sd->s_links)) |
522 | goto out; |
523 | |
524 | ret = 0; |
525 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { |
526 | if (!sd->s_element || |
527 | (sd->s_type & CONFIGFS_NOT_PINNED)) |
528 | continue; |
529 | if (sd->s_type & CONFIGFS_USET_DEFAULT) { |
530 | /* Abort if racing with mkdir() */ |
531 | if (sd->s_type & CONFIGFS_USET_IN_MKDIR) { |
532 | if (wait_mutex) |
533 | *wait_mutex = &sd->s_dentry->d_inode->i_mutex; |
534 | return -EAGAIN; |
535 | } |
536 | |
537 | /* |
538 | * Yup, recursive. If there's a problem, blame |
539 | * deep nesting of default_groups |
540 | */ |
541 | ret = configfs_detach_prep(sd->s_dentry, wait_mutex); |
542 | if (!ret) |
543 | continue; |
544 | } else |
545 | ret = -ENOTEMPTY; |
546 | |
547 | break; |
548 | } |
549 | |
550 | out: |
551 | return ret; |
552 | } |
553 | |
554 | /* |
555 | * Walk the tree, resetting CONFIGFS_USET_DROPPING wherever it was |
556 | * set. |
557 | */ |
558 | static void configfs_detach_rollback(struct dentry *dentry) |
559 | { |
560 | struct configfs_dirent *parent_sd = dentry->d_fsdata; |
561 | struct configfs_dirent *sd; |
562 | |
563 | parent_sd->s_type &= ~CONFIGFS_USET_DROPPING; |
564 | |
565 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) |
566 | if (sd->s_type & CONFIGFS_USET_DEFAULT) |
567 | configfs_detach_rollback(sd->s_dentry); |
568 | } |
569 | |
570 | static void detach_attrs(struct config_item * item) |
571 | { |
572 | struct dentry * dentry = dget(item->ci_dentry); |
573 | struct configfs_dirent * parent_sd; |
574 | struct configfs_dirent * sd, * tmp; |
575 | |
576 | if (!dentry) |
577 | return; |
578 | |
579 | pr_debug("configfs %s: dropping attrs for dir\n", |
580 | dentry->d_name.name); |
581 | |
582 | parent_sd = dentry->d_fsdata; |
583 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { |
584 | if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED)) |
585 | continue; |
586 | spin_lock(&configfs_dirent_lock); |
587 | list_del_init(&sd->s_sibling); |
588 | spin_unlock(&configfs_dirent_lock); |
589 | configfs_drop_dentry(sd, dentry); |
590 | configfs_put(sd); |
591 | } |
592 | |
593 | /** |
594 | * Drop reference from dget() on entrance. |
595 | */ |
596 | dput(dentry); |
597 | } |
598 | |
599 | static int populate_attrs(struct config_item *item) |
600 | { |
601 | struct config_item_type *t = item->ci_type; |
602 | struct configfs_attribute *attr; |
603 | int error = 0; |
604 | int i; |
605 | |
606 | if (!t) |
607 | return -EINVAL; |
608 | if (t->ct_attrs) { |
609 | for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) { |
610 | if ((error = configfs_create_file(item, attr))) |
611 | break; |
612 | } |
613 | } |
614 | |
615 | if (error) |
616 | detach_attrs(item); |
617 | |
618 | return error; |
619 | } |
620 | |
621 | static int configfs_attach_group(struct config_item *parent_item, |
622 | struct config_item *item, |
623 | struct dentry *dentry); |
624 | static void configfs_detach_group(struct config_item *item); |
625 | |
626 | static void detach_groups(struct config_group *group) |
627 | { |
628 | struct dentry * dentry = dget(group->cg_item.ci_dentry); |
629 | struct dentry *child; |
630 | struct configfs_dirent *parent_sd; |
631 | struct configfs_dirent *sd, *tmp; |
632 | |
633 | if (!dentry) |
634 | return; |
635 | |
636 | parent_sd = dentry->d_fsdata; |
637 | list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) { |
638 | if (!sd->s_element || |
639 | !(sd->s_type & CONFIGFS_USET_DEFAULT)) |
640 | continue; |
641 | |
642 | child = sd->s_dentry; |
643 | |
644 | mutex_lock(&child->d_inode->i_mutex); |
645 | |
646 | configfs_detach_group(sd->s_element); |
647 | child->d_inode->i_flags |= S_DEAD; |
648 | |
649 | mutex_unlock(&child->d_inode->i_mutex); |
650 | |
651 | d_delete(child); |
652 | dput(child); |
653 | } |
654 | |
655 | /** |
656 | * Drop reference from dget() on entrance. |
657 | */ |
658 | dput(dentry); |
659 | } |
660 | |
661 | /* |
662 | * This fakes mkdir(2) on a default_groups[] entry. It |
663 | * creates a dentry, attachs it, and then does fixup |
664 | * on the sd->s_type. |
665 | * |
666 | * We could, perhaps, tweak our parent's ->mkdir for a minute and |
667 | * try using vfs_mkdir. Just a thought. |
668 | */ |
669 | static int create_default_group(struct config_group *parent_group, |
670 | struct config_group *group) |
671 | { |
672 | int ret; |
673 | struct qstr name; |
674 | struct configfs_dirent *sd; |
675 | /* We trust the caller holds a reference to parent */ |
676 | struct dentry *child, *parent = parent_group->cg_item.ci_dentry; |
677 | |
678 | if (!group->cg_item.ci_name) |
679 | group->cg_item.ci_name = group->cg_item.ci_namebuf; |
680 | name.name = group->cg_item.ci_name; |
681 | name.len = strlen(name.name); |
682 | name.hash = full_name_hash(name.name, name.len); |
683 | |
684 | ret = -ENOMEM; |
685 | child = d_alloc(parent, &name); |
686 | if (child) { |
687 | d_add(child, NULL); |
688 | |
689 | ret = configfs_attach_group(&parent_group->cg_item, |
690 | &group->cg_item, child); |
691 | if (!ret) { |
692 | sd = child->d_fsdata; |
693 | sd->s_type |= CONFIGFS_USET_DEFAULT; |
694 | } else { |
695 | d_delete(child); |
696 | dput(child); |
697 | } |
698 | } |
699 | |
700 | return ret; |
701 | } |
702 | |
703 | static int populate_groups(struct config_group *group) |
704 | { |
705 | struct config_group *new_group; |
706 | int ret = 0; |
707 | int i; |
708 | |
709 | if (group->default_groups) { |
710 | for (i = 0; group->default_groups[i]; i++) { |
711 | new_group = group->default_groups[i]; |
712 | |
713 | ret = create_default_group(group, new_group); |
714 | if (ret) { |
715 | detach_groups(group); |
716 | break; |
717 | } |
718 | } |
719 | } |
720 | |
721 | return ret; |
722 | } |
723 | |
724 | /* |
725 | * All of link_obj/unlink_obj/link_group/unlink_group require that |
726 | * subsys->su_mutex is held. |
727 | */ |
728 | |
729 | static void unlink_obj(struct config_item *item) |
730 | { |
731 | struct config_group *group; |
732 | |
733 | group = item->ci_group; |
734 | if (group) { |
735 | list_del_init(&item->ci_entry); |
736 | |
737 | item->ci_group = NULL; |
738 | item->ci_parent = NULL; |
739 | |
740 | /* Drop the reference for ci_entry */ |
741 | config_item_put(item); |
742 | |
743 | /* Drop the reference for ci_parent */ |
744 | config_group_put(group); |
745 | } |
746 | } |
747 | |
748 | static void link_obj(struct config_item *parent_item, struct config_item *item) |
749 | { |
750 | /* |
751 | * Parent seems redundant with group, but it makes certain |
752 | * traversals much nicer. |
753 | */ |
754 | item->ci_parent = parent_item; |
755 | |
756 | /* |
757 | * We hold a reference on the parent for the child's ci_parent |
758 | * link. |
759 | */ |
760 | item->ci_group = config_group_get(to_config_group(parent_item)); |
761 | list_add_tail(&item->ci_entry, &item->ci_group->cg_children); |
762 | |
763 | /* |
764 | * We hold a reference on the child for ci_entry on the parent's |
765 | * cg_children |
766 | */ |
767 | config_item_get(item); |
768 | } |
769 | |
770 | static void unlink_group(struct config_group *group) |
771 | { |
772 | int i; |
773 | struct config_group *new_group; |
774 | |
775 | if (group->default_groups) { |
776 | for (i = 0; group->default_groups[i]; i++) { |
777 | new_group = group->default_groups[i]; |
778 | unlink_group(new_group); |
779 | } |
780 | } |
781 | |
782 | group->cg_subsys = NULL; |
783 | unlink_obj(&group->cg_item); |
784 | } |
785 | |
786 | static void link_group(struct config_group *parent_group, struct config_group *group) |
787 | { |
788 | int i; |
789 | struct config_group *new_group; |
790 | struct configfs_subsystem *subsys = NULL; /* gcc is a turd */ |
791 | |
792 | link_obj(&parent_group->cg_item, &group->cg_item); |
793 | |
794 | if (parent_group->cg_subsys) |
795 | subsys = parent_group->cg_subsys; |
796 | else if (configfs_is_root(&parent_group->cg_item)) |
797 | subsys = to_configfs_subsystem(group); |
798 | else |
799 | BUG(); |
800 | group->cg_subsys = subsys; |
801 | |
802 | if (group->default_groups) { |
803 | for (i = 0; group->default_groups[i]; i++) { |
804 | new_group = group->default_groups[i]; |
805 | link_group(group, new_group); |
806 | } |
807 | } |
808 | } |
809 | |
810 | /* |
811 | * The goal is that configfs_attach_item() (and |
812 | * configfs_attach_group()) can be called from either the VFS or this |
813 | * module. That is, they assume that the items have been created, |
814 | * the dentry allocated, and the dcache is all ready to go. |
815 | * |
816 | * If they fail, they must clean up after themselves as if they |
817 | * had never been called. The caller (VFS or local function) will |
818 | * handle cleaning up the dcache bits. |
819 | * |
820 | * configfs_detach_group() and configfs_detach_item() behave similarly on |
821 | * the way out. They assume that the proper semaphores are held, they |
822 | * clean up the configfs items, and they expect their callers will |
823 | * handle the dcache bits. |
824 | */ |
825 | static int configfs_attach_item(struct config_item *parent_item, |
826 | struct config_item *item, |
827 | struct dentry *dentry) |
828 | { |
829 | int ret; |
830 | |
831 | ret = configfs_create_dir(item, dentry); |
832 | if (!ret) { |
833 | ret = populate_attrs(item); |
834 | if (ret) { |
835 | /* |
836 | * We are going to remove an inode and its dentry but |
837 | * the VFS may already have hit and used them. Thus, |
838 | * we must lock them as rmdir() would. |
839 | */ |
840 | mutex_lock(&dentry->d_inode->i_mutex); |
841 | configfs_remove_dir(item); |
842 | dentry->d_inode->i_flags |= S_DEAD; |
843 | mutex_unlock(&dentry->d_inode->i_mutex); |
844 | d_delete(dentry); |
845 | } |
846 | } |
847 | |
848 | return ret; |
849 | } |
850 | |
851 | /* Caller holds the mutex of the item's inode */ |
852 | static void configfs_detach_item(struct config_item *item) |
853 | { |
854 | detach_attrs(item); |
855 | configfs_remove_dir(item); |
856 | } |
857 | |
858 | static int configfs_attach_group(struct config_item *parent_item, |
859 | struct config_item *item, |
860 | struct dentry *dentry) |
861 | { |
862 | int ret; |
863 | struct configfs_dirent *sd; |
864 | |
865 | ret = configfs_attach_item(parent_item, item, dentry); |
866 | if (!ret) { |
867 | sd = dentry->d_fsdata; |
868 | sd->s_type |= CONFIGFS_USET_DIR; |
869 | |
870 | /* |
871 | * FYI, we're faking mkdir in populate_groups() |
872 | * We must lock the group's inode to avoid races with the VFS |
873 | * which can already hit the inode and try to add/remove entries |
874 | * under it. |
875 | * |
876 | * We must also lock the inode to remove it safely in case of |
877 | * error, as rmdir() would. |
878 | */ |
879 | mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); |
880 | configfs_adjust_dir_dirent_depth_before_populate(sd); |
881 | ret = populate_groups(to_config_group(item)); |
882 | if (ret) { |
883 | configfs_detach_item(item); |
884 | dentry->d_inode->i_flags |= S_DEAD; |
885 | } |
886 | configfs_adjust_dir_dirent_depth_after_populate(sd); |
887 | mutex_unlock(&dentry->d_inode->i_mutex); |
888 | if (ret) |
889 | d_delete(dentry); |
890 | } |
891 | |
892 | return ret; |
893 | } |
894 | |
895 | /* Caller holds the mutex of the group's inode */ |
896 | static void configfs_detach_group(struct config_item *item) |
897 | { |
898 | detach_groups(to_config_group(item)); |
899 | configfs_detach_item(item); |
900 | } |
901 | |
902 | /* |
903 | * After the item has been detached from the filesystem view, we are |
904 | * ready to tear it out of the hierarchy. Notify the client before |
905 | * we do that so they can perform any cleanup that requires |
906 | * navigating the hierarchy. A client does not need to provide this |
907 | * callback. The subsystem semaphore MUST be held by the caller, and |
908 | * references must be valid for both items. It also assumes the |
909 | * caller has validated ci_type. |
910 | */ |
911 | static void client_disconnect_notify(struct config_item *parent_item, |
912 | struct config_item *item) |
913 | { |
914 | struct config_item_type *type; |
915 | |
916 | type = parent_item->ci_type; |
917 | BUG_ON(!type); |
918 | |
919 | if (type->ct_group_ops && type->ct_group_ops->disconnect_notify) |
920 | type->ct_group_ops->disconnect_notify(to_config_group(parent_item), |
921 | item); |
922 | } |
923 | |
924 | /* |
925 | * Drop the initial reference from make_item()/make_group() |
926 | * This function assumes that reference is held on item |
927 | * and that item holds a valid reference to the parent. Also, it |
928 | * assumes the caller has validated ci_type. |
929 | */ |
930 | static void client_drop_item(struct config_item *parent_item, |
931 | struct config_item *item) |
932 | { |
933 | struct config_item_type *type; |
934 | |
935 | type = parent_item->ci_type; |
936 | BUG_ON(!type); |
937 | |
938 | /* |
939 | * If ->drop_item() exists, it is responsible for the |
940 | * config_item_put(). |
941 | */ |
942 | if (type->ct_group_ops && type->ct_group_ops->drop_item) |
943 | type->ct_group_ops->drop_item(to_config_group(parent_item), |
944 | item); |
945 | else |
946 | config_item_put(item); |
947 | } |
948 | |
949 | #ifdef DEBUG |
950 | static void configfs_dump_one(struct configfs_dirent *sd, int level) |
951 | { |
952 | printk(KERN_INFO "%*s\"%s\":\n", level, " ", configfs_get_name(sd)); |
953 | |
954 | #define type_print(_type) if (sd->s_type & _type) printk(KERN_INFO "%*s %s\n", level, " ", #_type); |
955 | type_print(CONFIGFS_ROOT); |
956 | type_print(CONFIGFS_DIR); |
957 | type_print(CONFIGFS_ITEM_ATTR); |
958 | type_print(CONFIGFS_ITEM_LINK); |
959 | type_print(CONFIGFS_USET_DIR); |
960 | type_print(CONFIGFS_USET_DEFAULT); |
961 | type_print(CONFIGFS_USET_DROPPING); |
962 | #undef type_print |
963 | } |
964 | |
965 | static int configfs_dump(struct configfs_dirent *sd, int level) |
966 | { |
967 | struct configfs_dirent *child_sd; |
968 | int ret = 0; |
969 | |
970 | configfs_dump_one(sd, level); |
971 | |
972 | if (!(sd->s_type & (CONFIGFS_DIR|CONFIGFS_ROOT))) |
973 | return 0; |
974 | |
975 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) { |
976 | ret = configfs_dump(child_sd, level + 2); |
977 | if (ret) |
978 | break; |
979 | } |
980 | |
981 | return ret; |
982 | } |
983 | #endif |
984 | |
985 | |
986 | /* |
987 | * configfs_depend_item() and configfs_undepend_item() |
988 | * |
989 | * WARNING: Do not call these from a configfs callback! |
990 | * |
991 | * This describes these functions and their helpers. |
992 | * |
993 | * Allow another kernel system to depend on a config_item. If this |
994 | * happens, the item cannot go away until the dependant can live without |
995 | * it. The idea is to give client modules as simple an interface as |
996 | * possible. When a system asks them to depend on an item, they just |
997 | * call configfs_depend_item(). If the item is live and the client |
998 | * driver is in good shape, we'll happily do the work for them. |
999 | * |
1000 | * Why is the locking complex? Because configfs uses the VFS to handle |
1001 | * all locking, but this function is called outside the normal |
1002 | * VFS->configfs path. So it must take VFS locks to prevent the |
1003 | * VFS->configfs stuff (configfs_mkdir(), configfs_rmdir(), etc). This is |
1004 | * why you can't call these functions underneath configfs callbacks. |
1005 | * |
1006 | * Note, btw, that this can be called at *any* time, even when a configfs |
1007 | * subsystem isn't registered, or when configfs is loading or unloading. |
1008 | * Just like configfs_register_subsystem(). So we take the same |
1009 | * precautions. We pin the filesystem. We lock configfs_dirent_lock. |
1010 | * If we can find the target item in the |
1011 | * configfs tree, it must be part of the subsystem tree as well, so we |
1012 | * do not need the subsystem semaphore. Holding configfs_dirent_lock helps |
1013 | * locking out mkdir() and rmdir(), who might be racing us. |
1014 | */ |
1015 | |
1016 | /* |
1017 | * configfs_depend_prep() |
1018 | * |
1019 | * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are |
1020 | * attributes. This is similar but not the same to configfs_detach_prep(). |
1021 | * Note that configfs_detach_prep() expects the parent to be locked when it |
1022 | * is called, but we lock the parent *inside* configfs_depend_prep(). We |
1023 | * do that so we can unlock it if we find nothing. |
1024 | * |
1025 | * Here we do a depth-first search of the dentry hierarchy looking for |
1026 | * our object. |
1027 | * We deliberately ignore items tagged as dropping since they are virtually |
1028 | * dead, as well as items in the middle of attachment since they virtually |
1029 | * do not exist yet. This completes the locking out of racing mkdir() and |
1030 | * rmdir(). |
1031 | * Note: subdirectories in the middle of attachment start with s_type = |
1032 | * CONFIGFS_DIR|CONFIGFS_USET_CREATING set by create_dir(). When |
1033 | * CONFIGFS_USET_CREATING is set, we ignore the item. The actual set of |
1034 | * s_type is in configfs_new_dirent(), which has configfs_dirent_lock. |
1035 | * |
1036 | * If the target is not found, -ENOENT is bubbled up. |
1037 | * |
1038 | * This adds a requirement that all config_items be unique! |
1039 | * |
1040 | * This is recursive. There isn't |
1041 | * much on the stack, though, so folks that need this function - be careful |
1042 | * about your stack! Patches will be accepted to make it iterative. |
1043 | */ |
1044 | static int configfs_depend_prep(struct dentry *origin, |
1045 | struct config_item *target) |
1046 | { |
1047 | struct configfs_dirent *child_sd, *sd = origin->d_fsdata; |
1048 | int ret = 0; |
1049 | |
1050 | BUG_ON(!origin || !sd); |
1051 | |
1052 | if (sd->s_element == target) /* Boo-yah */ |
1053 | goto out; |
1054 | |
1055 | list_for_each_entry(child_sd, &sd->s_children, s_sibling) { |
1056 | if ((child_sd->s_type & CONFIGFS_DIR) && |
1057 | !(child_sd->s_type & CONFIGFS_USET_DROPPING) && |
1058 | !(child_sd->s_type & CONFIGFS_USET_CREATING)) { |
1059 | ret = configfs_depend_prep(child_sd->s_dentry, |
1060 | target); |
1061 | if (!ret) |
1062 | goto out; /* Child path boo-yah */ |
1063 | } |
1064 | } |
1065 | |
1066 | /* We looped all our children and didn't find target */ |
1067 | ret = -ENOENT; |
1068 | |
1069 | out: |
1070 | return ret; |
1071 | } |
1072 | |
1073 | int configfs_depend_item(struct configfs_subsystem *subsys, |
1074 | struct config_item *target) |
1075 | { |
1076 | int ret; |
1077 | struct configfs_dirent *p, *root_sd, *subsys_sd = NULL; |
1078 | struct config_item *s_item = &subsys->su_group.cg_item; |
1079 | |
1080 | /* |
1081 | * Pin the configfs filesystem. This means we can safely access |
1082 | * the root of the configfs filesystem. |
1083 | */ |
1084 | ret = configfs_pin_fs(); |
1085 | if (ret) |
1086 | return ret; |
1087 | |
1088 | /* |
1089 | * Next, lock the root directory. We're going to check that the |
1090 | * subsystem is really registered, and so we need to lock out |
1091 | * configfs_[un]register_subsystem(). |
1092 | */ |
1093 | mutex_lock(&configfs_sb->s_root->d_inode->i_mutex); |
1094 | |
1095 | root_sd = configfs_sb->s_root->d_fsdata; |
1096 | |
1097 | list_for_each_entry(p, &root_sd->s_children, s_sibling) { |
1098 | if (p->s_type & CONFIGFS_DIR) { |
1099 | if (p->s_element == s_item) { |
1100 | subsys_sd = p; |
1101 | break; |
1102 | } |
1103 | } |
1104 | } |
1105 | |
1106 | if (!subsys_sd) { |
1107 | ret = -ENOENT; |
1108 | goto out_unlock_fs; |
1109 | } |
1110 | |
1111 | /* Ok, now we can trust subsys/s_item */ |
1112 | |
1113 | spin_lock(&configfs_dirent_lock); |
1114 | /* Scan the tree, return 0 if found */ |
1115 | ret = configfs_depend_prep(subsys_sd->s_dentry, target); |
1116 | if (ret) |
1117 | goto out_unlock_dirent_lock; |
1118 | |
1119 | /* |
1120 | * We are sure that the item is not about to be removed by rmdir(), and |
1121 | * not in the middle of attachment by mkdir(). |
1122 | */ |
1123 | p = target->ci_dentry->d_fsdata; |
1124 | p->s_dependent_count += 1; |
1125 | |
1126 | out_unlock_dirent_lock: |
1127 | spin_unlock(&configfs_dirent_lock); |
1128 | out_unlock_fs: |
1129 | mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex); |
1130 | |
1131 | /* |
1132 | * If we succeeded, the fs is pinned via other methods. If not, |
1133 | * we're done with it anyway. So release_fs() is always right. |
1134 | */ |
1135 | configfs_release_fs(); |
1136 | |
1137 | return ret; |
1138 | } |
1139 | EXPORT_SYMBOL(configfs_depend_item); |
1140 | |
1141 | /* |
1142 | * Release the dependent linkage. This is much simpler than |
1143 | * configfs_depend_item() because we know that that the client driver is |
1144 | * pinned, thus the subsystem is pinned, and therefore configfs is pinned. |
1145 | */ |
1146 | void configfs_undepend_item(struct configfs_subsystem *subsys, |
1147 | struct config_item *target) |
1148 | { |
1149 | struct configfs_dirent *sd; |
1150 | |
1151 | /* |
1152 | * Since we can trust everything is pinned, we just need |
1153 | * configfs_dirent_lock. |
1154 | */ |
1155 | spin_lock(&configfs_dirent_lock); |
1156 | |
1157 | sd = target->ci_dentry->d_fsdata; |
1158 | BUG_ON(sd->s_dependent_count < 1); |
1159 | |
1160 | sd->s_dependent_count -= 1; |
1161 | |
1162 | /* |
1163 | * After this unlock, we cannot trust the item to stay alive! |
1164 | * DO NOT REFERENCE item after this unlock. |
1165 | */ |
1166 | spin_unlock(&configfs_dirent_lock); |
1167 | } |
1168 | EXPORT_SYMBOL(configfs_undepend_item); |
1169 | |
1170 | static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) |
1171 | { |
1172 | int ret = 0; |
1173 | int module_got = 0; |
1174 | struct config_group *group = NULL; |
1175 | struct config_item *item = NULL; |
1176 | struct config_item *parent_item; |
1177 | struct configfs_subsystem *subsys; |
1178 | struct configfs_dirent *sd; |
1179 | struct config_item_type *type; |
1180 | struct module *subsys_owner = NULL, *new_item_owner = NULL; |
1181 | char *name; |
1182 | |
1183 | if (dentry->d_parent == configfs_sb->s_root) { |
1184 | ret = -EPERM; |
1185 | goto out; |
1186 | } |
1187 | |
1188 | sd = dentry->d_parent->d_fsdata; |
1189 | |
1190 | /* |
1191 | * Fake invisibility if dir belongs to a group/default groups hierarchy |
1192 | * being attached |
1193 | */ |
1194 | if (!configfs_dirent_is_ready(sd)) { |
1195 | ret = -ENOENT; |
1196 | goto out; |
1197 | } |
1198 | |
1199 | if (!(sd->s_type & CONFIGFS_USET_DIR)) { |
1200 | ret = -EPERM; |
1201 | goto out; |
1202 | } |
1203 | |
1204 | /* Get a working ref for the duration of this function */ |
1205 | parent_item = configfs_get_config_item(dentry->d_parent); |
1206 | type = parent_item->ci_type; |
1207 | subsys = to_config_group(parent_item)->cg_subsys; |
1208 | BUG_ON(!subsys); |
1209 | |
1210 | if (!type || !type->ct_group_ops || |
1211 | (!type->ct_group_ops->make_group && |
1212 | !type->ct_group_ops->make_item)) { |
1213 | ret = -EPERM; /* Lack-of-mkdir returns -EPERM */ |
1214 | goto out_put; |
1215 | } |
1216 | |
1217 | /* |
1218 | * The subsystem may belong to a different module than the item |
1219 | * being created. We don't want to safely pin the new item but |
1220 | * fail to pin the subsystem it sits under. |
1221 | */ |
1222 | if (!subsys->su_group.cg_item.ci_type) { |
1223 | ret = -EINVAL; |
1224 | goto out_put; |
1225 | } |
1226 | subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; |
1227 | if (!try_module_get(subsys_owner)) { |
1228 | ret = -EINVAL; |
1229 | goto out_put; |
1230 | } |
1231 | |
1232 | name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL); |
1233 | if (!name) { |
1234 | ret = -ENOMEM; |
1235 | goto out_subsys_put; |
1236 | } |
1237 | |
1238 | snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name); |
1239 | |
1240 | mutex_lock(&subsys->su_mutex); |
1241 | if (type->ct_group_ops->make_group) { |
1242 | group = type->ct_group_ops->make_group(to_config_group(parent_item), name); |
1243 | if (!group) |
1244 | group = ERR_PTR(-ENOMEM); |
1245 | if (!IS_ERR(group)) { |
1246 | link_group(to_config_group(parent_item), group); |
1247 | item = &group->cg_item; |
1248 | } else |
1249 | ret = PTR_ERR(group); |
1250 | } else { |
1251 | item = type->ct_group_ops->make_item(to_config_group(parent_item), name); |
1252 | if (!item) |
1253 | item = ERR_PTR(-ENOMEM); |
1254 | if (!IS_ERR(item)) |
1255 | link_obj(parent_item, item); |
1256 | else |
1257 | ret = PTR_ERR(item); |
1258 | } |
1259 | mutex_unlock(&subsys->su_mutex); |
1260 | |
1261 | kfree(name); |
1262 | if (ret) { |
1263 | /* |
1264 | * If ret != 0, then link_obj() was never called. |
1265 | * There are no extra references to clean up. |
1266 | */ |
1267 | goto out_subsys_put; |
1268 | } |
1269 | |
1270 | /* |
1271 | * link_obj() has been called (via link_group() for groups). |
1272 | * From here on out, errors must clean that up. |
1273 | */ |
1274 | |
1275 | type = item->ci_type; |
1276 | if (!type) { |
1277 | ret = -EINVAL; |
1278 | goto out_unlink; |
1279 | } |
1280 | |
1281 | new_item_owner = type->ct_owner; |
1282 | if (!try_module_get(new_item_owner)) { |
1283 | ret = -EINVAL; |
1284 | goto out_unlink; |
1285 | } |
1286 | |
1287 | /* |
1288 | * I hate doing it this way, but if there is |
1289 | * an error, module_put() probably should |
1290 | * happen after any cleanup. |
1291 | */ |
1292 | module_got = 1; |
1293 | |
1294 | /* |
1295 | * Make racing rmdir() fail if it did not tag parent with |
1296 | * CONFIGFS_USET_DROPPING |
1297 | * Note: if CONFIGFS_USET_DROPPING is already set, attach_group() will |
1298 | * fail and let rmdir() terminate correctly |
1299 | */ |
1300 | spin_lock(&configfs_dirent_lock); |
1301 | /* This will make configfs_detach_prep() fail */ |
1302 | sd->s_type |= CONFIGFS_USET_IN_MKDIR; |
1303 | spin_unlock(&configfs_dirent_lock); |
1304 | |
1305 | if (group) |
1306 | ret = configfs_attach_group(parent_item, item, dentry); |
1307 | else |
1308 | ret = configfs_attach_item(parent_item, item, dentry); |
1309 | |
1310 | spin_lock(&configfs_dirent_lock); |
1311 | sd->s_type &= ~CONFIGFS_USET_IN_MKDIR; |
1312 | if (!ret) |
1313 | configfs_dir_set_ready(dentry->d_fsdata); |
1314 | spin_unlock(&configfs_dirent_lock); |
1315 | |
1316 | out_unlink: |
1317 | if (ret) { |
1318 | /* Tear down everything we built up */ |
1319 | mutex_lock(&subsys->su_mutex); |
1320 | |
1321 | client_disconnect_notify(parent_item, item); |
1322 | if (group) |
1323 | unlink_group(group); |
1324 | else |
1325 | unlink_obj(item); |
1326 | client_drop_item(parent_item, item); |
1327 | |
1328 | mutex_unlock(&subsys->su_mutex); |
1329 | |
1330 | if (module_got) |
1331 | module_put(new_item_owner); |
1332 | } |
1333 | |
1334 | out_subsys_put: |
1335 | if (ret) |
1336 | module_put(subsys_owner); |
1337 | |
1338 | out_put: |
1339 | /* |
1340 | * link_obj()/link_group() took a reference from child->parent, |
1341 | * so the parent is safely pinned. We can drop our working |
1342 | * reference. |
1343 | */ |
1344 | config_item_put(parent_item); |
1345 | |
1346 | out: |
1347 | return ret; |
1348 | } |
1349 | |
1350 | static int configfs_rmdir(struct inode *dir, struct dentry *dentry) |
1351 | { |
1352 | struct config_item *parent_item; |
1353 | struct config_item *item; |
1354 | struct configfs_subsystem *subsys; |
1355 | struct configfs_dirent *sd; |
1356 | struct module *subsys_owner = NULL, *dead_item_owner = NULL; |
1357 | int ret; |
1358 | |
1359 | if (dentry->d_parent == configfs_sb->s_root) |
1360 | return -EPERM; |
1361 | |
1362 | sd = dentry->d_fsdata; |
1363 | if (sd->s_type & CONFIGFS_USET_DEFAULT) |
1364 | return -EPERM; |
1365 | |
1366 | /* Get a working ref until we have the child */ |
1367 | parent_item = configfs_get_config_item(dentry->d_parent); |
1368 | subsys = to_config_group(parent_item)->cg_subsys; |
1369 | BUG_ON(!subsys); |
1370 | |
1371 | if (!parent_item->ci_type) { |
1372 | config_item_put(parent_item); |
1373 | return -EINVAL; |
1374 | } |
1375 | |
1376 | /* configfs_mkdir() shouldn't have allowed this */ |
1377 | BUG_ON(!subsys->su_group.cg_item.ci_type); |
1378 | subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner; |
1379 | |
1380 | /* |
1381 | * Ensure that no racing symlink() will make detach_prep() fail while |
1382 | * the new link is temporarily attached |
1383 | */ |
1384 | do { |
1385 | struct mutex *wait_mutex; |
1386 | |
1387 | mutex_lock(&configfs_symlink_mutex); |
1388 | spin_lock(&configfs_dirent_lock); |
1389 | /* |
1390 | * Here's where we check for dependents. We're protected by |
1391 | * configfs_dirent_lock. |
1392 | * If no dependent, atomically tag the item as dropping. |
1393 | */ |
1394 | ret = sd->s_dependent_count ? -EBUSY : 0; |
1395 | if (!ret) { |
1396 | ret = configfs_detach_prep(dentry, &wait_mutex); |
1397 | if (ret) |
1398 | configfs_detach_rollback(dentry); |
1399 | } |
1400 | spin_unlock(&configfs_dirent_lock); |
1401 | mutex_unlock(&configfs_symlink_mutex); |
1402 | |
1403 | if (ret) { |
1404 | if (ret != -EAGAIN) { |
1405 | config_item_put(parent_item); |
1406 | return ret; |
1407 | } |
1408 | |
1409 | /* Wait until the racing operation terminates */ |
1410 | mutex_lock(wait_mutex); |
1411 | mutex_unlock(wait_mutex); |
1412 | } |
1413 | } while (ret == -EAGAIN); |
1414 | |
1415 | /* Get a working ref for the duration of this function */ |
1416 | item = configfs_get_config_item(dentry); |
1417 | |
1418 | /* Drop reference from above, item already holds one. */ |
1419 | config_item_put(parent_item); |
1420 | |
1421 | if (item->ci_type) |
1422 | dead_item_owner = item->ci_type->ct_owner; |
1423 | |
1424 | if (sd->s_type & CONFIGFS_USET_DIR) { |
1425 | configfs_detach_group(item); |
1426 | |
1427 | mutex_lock(&subsys->su_mutex); |
1428 | client_disconnect_notify(parent_item, item); |
1429 | unlink_group(to_config_group(item)); |
1430 | } else { |
1431 | configfs_detach_item(item); |
1432 | |
1433 | mutex_lock(&subsys->su_mutex); |
1434 | client_disconnect_notify(parent_item, item); |
1435 | unlink_obj(item); |
1436 | } |
1437 | |
1438 | client_drop_item(parent_item, item); |
1439 | mutex_unlock(&subsys->su_mutex); |
1440 | |
1441 | /* Drop our reference from above */ |
1442 | config_item_put(item); |
1443 | |
1444 | module_put(dead_item_owner); |
1445 | module_put(subsys_owner); |
1446 | |
1447 | return 0; |
1448 | } |
1449 | |
1450 | const struct inode_operations configfs_dir_inode_operations = { |
1451 | .mkdir = configfs_mkdir, |
1452 | .rmdir = configfs_rmdir, |
1453 | .symlink = configfs_symlink, |
1454 | .unlink = configfs_unlink, |
1455 | .lookup = configfs_lookup, |
1456 | .setattr = configfs_setattr, |
1457 | }; |
1458 | |
1459 | #if 0 |
1460 | int configfs_rename_dir(struct config_item * item, const char *new_name) |
1461 | { |
1462 | int error = 0; |
1463 | struct dentry * new_dentry, * parent; |
1464 | |
1465 | if (!strcmp(config_item_name(item), new_name)) |
1466 | return -EINVAL; |
1467 | |
1468 | if (!item->parent) |
1469 | return -EINVAL; |
1470 | |
1471 | down_write(&configfs_rename_sem); |
1472 | parent = item->parent->dentry; |
1473 | |
1474 | mutex_lock(&parent->d_inode->i_mutex); |
1475 | |
1476 | new_dentry = lookup_one_len(new_name, parent, strlen(new_name)); |
1477 | if (!IS_ERR(new_dentry)) { |
1478 | if (!new_dentry->d_inode) { |
1479 | error = config_item_set_name(item, "%s", new_name); |
1480 | if (!error) { |
1481 | d_add(new_dentry, NULL); |
1482 | d_move(item->dentry, new_dentry); |
1483 | } |
1484 | else |
1485 | d_delete(new_dentry); |
1486 | } else |
1487 | error = -EEXIST; |
1488 | dput(new_dentry); |
1489 | } |
1490 | mutex_unlock(&parent->d_inode->i_mutex); |
1491 | up_write(&configfs_rename_sem); |
1492 | |
1493 | return error; |
1494 | } |
1495 | #endif |
1496 | |
1497 | static int configfs_dir_open(struct inode *inode, struct file *file) |
1498 | { |
1499 | struct dentry * dentry = file->f_path.dentry; |
1500 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
1501 | int err; |
1502 | |
1503 | mutex_lock(&dentry->d_inode->i_mutex); |
1504 | /* |
1505 | * Fake invisibility if dir belongs to a group/default groups hierarchy |
1506 | * being attached |
1507 | */ |
1508 | err = -ENOENT; |
1509 | if (configfs_dirent_is_ready(parent_sd)) { |
1510 | file->private_data = configfs_new_dirent(parent_sd, NULL, 0); |
1511 | if (IS_ERR(file->private_data)) |
1512 | err = PTR_ERR(file->private_data); |
1513 | else |
1514 | err = 0; |
1515 | } |
1516 | mutex_unlock(&dentry->d_inode->i_mutex); |
1517 | |
1518 | return err; |
1519 | } |
1520 | |
1521 | static int configfs_dir_close(struct inode *inode, struct file *file) |
1522 | { |
1523 | struct dentry * dentry = file->f_path.dentry; |
1524 | struct configfs_dirent * cursor = file->private_data; |
1525 | |
1526 | mutex_lock(&dentry->d_inode->i_mutex); |
1527 | spin_lock(&configfs_dirent_lock); |
1528 | list_del_init(&cursor->s_sibling); |
1529 | spin_unlock(&configfs_dirent_lock); |
1530 | mutex_unlock(&dentry->d_inode->i_mutex); |
1531 | |
1532 | release_configfs_dirent(cursor); |
1533 | |
1534 | return 0; |
1535 | } |
1536 | |
1537 | /* Relationship between s_mode and the DT_xxx types */ |
1538 | static inline unsigned char dt_type(struct configfs_dirent *sd) |
1539 | { |
1540 | return (sd->s_mode >> 12) & 15; |
1541 | } |
1542 | |
1543 | static int configfs_readdir(struct file * filp, void * dirent, filldir_t filldir) |
1544 | { |
1545 | struct dentry *dentry = filp->f_path.dentry; |
1546 | struct configfs_dirent * parent_sd = dentry->d_fsdata; |
1547 | struct configfs_dirent *cursor = filp->private_data; |
1548 | struct list_head *p, *q = &cursor->s_sibling; |
1549 | ino_t ino; |
1550 | int i = filp->f_pos; |
1551 | |
1552 | switch (i) { |
1553 | case 0: |
1554 | ino = dentry->d_inode->i_ino; |
1555 | if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) |
1556 | break; |
1557 | filp->f_pos++; |
1558 | i++; |
1559 | /* fallthrough */ |
1560 | case 1: |
1561 | ino = parent_ino(dentry); |
1562 | if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) |
1563 | break; |
1564 | filp->f_pos++; |
1565 | i++; |
1566 | /* fallthrough */ |
1567 | default: |
1568 | if (filp->f_pos == 2) { |
1569 | spin_lock(&configfs_dirent_lock); |
1570 | list_move(q, &parent_sd->s_children); |
1571 | spin_unlock(&configfs_dirent_lock); |
1572 | } |
1573 | for (p=q->next; p!= &parent_sd->s_children; p=p->next) { |
1574 | struct configfs_dirent *next; |
1575 | const char * name; |
1576 | int len; |
1577 | |
1578 | next = list_entry(p, struct configfs_dirent, |
1579 | s_sibling); |
1580 | if (!next->s_element) |
1581 | continue; |
1582 | |
1583 | name = configfs_get_name(next); |
1584 | len = strlen(name); |
1585 | if (next->s_dentry) |
1586 | ino = next->s_dentry->d_inode->i_ino; |
1587 | else |
1588 | ino = iunique(configfs_sb, 2); |
1589 | |
1590 | if (filldir(dirent, name, len, filp->f_pos, ino, |
1591 | dt_type(next)) < 0) |
1592 | return 0; |
1593 | |
1594 | spin_lock(&configfs_dirent_lock); |
1595 | list_move(q, p); |
1596 | spin_unlock(&configfs_dirent_lock); |
1597 | p = q; |
1598 | filp->f_pos++; |
1599 | } |
1600 | } |
1601 | return 0; |
1602 | } |
1603 | |
1604 | static loff_t configfs_dir_lseek(struct file * file, loff_t offset, int origin) |
1605 | { |
1606 | struct dentry * dentry = file->f_path.dentry; |
1607 | |
1608 | mutex_lock(&dentry->d_inode->i_mutex); |
1609 | switch (origin) { |
1610 | case 1: |
1611 | offset += file->f_pos; |
1612 | case 0: |
1613 | if (offset >= 0) |
1614 | break; |
1615 | default: |
1616 | mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); |
1617 | return -EINVAL; |
1618 | } |
1619 | if (offset != file->f_pos) { |
1620 | file->f_pos = offset; |
1621 | if (file->f_pos >= 2) { |
1622 | struct configfs_dirent *sd = dentry->d_fsdata; |
1623 | struct configfs_dirent *cursor = file->private_data; |
1624 | struct list_head *p; |
1625 | loff_t n = file->f_pos - 2; |
1626 | |
1627 | spin_lock(&configfs_dirent_lock); |
1628 | list_del(&cursor->s_sibling); |
1629 | p = sd->s_children.next; |
1630 | while (n && p != &sd->s_children) { |
1631 | struct configfs_dirent *next; |
1632 | next = list_entry(p, struct configfs_dirent, |
1633 | s_sibling); |
1634 | if (next->s_element) |
1635 | n--; |
1636 | p = p->next; |
1637 | } |
1638 | list_add_tail(&cursor->s_sibling, p); |
1639 | spin_unlock(&configfs_dirent_lock); |
1640 | } |
1641 | } |
1642 | mutex_unlock(&dentry->d_inode->i_mutex); |
1643 | return offset; |
1644 | } |
1645 | |
1646 | const struct file_operations configfs_dir_operations = { |
1647 | .open = configfs_dir_open, |
1648 | .release = configfs_dir_close, |
1649 | .llseek = configfs_dir_lseek, |
1650 | .read = generic_read_dir, |
1651 | .readdir = configfs_readdir, |
1652 | }; |
1653 | |
1654 | int configfs_register_subsystem(struct configfs_subsystem *subsys) |
1655 | { |
1656 | int err; |
1657 | struct config_group *group = &subsys->su_group; |
1658 | struct qstr name; |
1659 | struct dentry *dentry; |
1660 | struct configfs_dirent *sd; |
1661 | |
1662 | err = configfs_pin_fs(); |
1663 | if (err) |
1664 | return err; |
1665 | |
1666 | if (!group->cg_item.ci_name) |
1667 | group->cg_item.ci_name = group->cg_item.ci_namebuf; |
1668 | |
1669 | sd = configfs_sb->s_root->d_fsdata; |
1670 | link_group(to_config_group(sd->s_element), group); |
1671 | |
1672 | mutex_lock_nested(&configfs_sb->s_root->d_inode->i_mutex, |
1673 | I_MUTEX_PARENT); |
1674 | |
1675 | name.name = group->cg_item.ci_name; |
1676 | name.len = strlen(name.name); |
1677 | name.hash = full_name_hash(name.name, name.len); |
1678 | |
1679 | err = -ENOMEM; |
1680 | dentry = d_alloc(configfs_sb->s_root, &name); |
1681 | if (dentry) { |
1682 | d_add(dentry, NULL); |
1683 | |
1684 | err = configfs_attach_group(sd->s_element, &group->cg_item, |
1685 | dentry); |
1686 | if (err) { |
1687 | d_delete(dentry); |
1688 | dput(dentry); |
1689 | } else { |
1690 | spin_lock(&configfs_dirent_lock); |
1691 | configfs_dir_set_ready(dentry->d_fsdata); |
1692 | spin_unlock(&configfs_dirent_lock); |
1693 | } |
1694 | } |
1695 | |
1696 | mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex); |
1697 | |
1698 | if (err) { |
1699 | unlink_group(group); |
1700 | configfs_release_fs(); |
1701 | } |
1702 | |
1703 | return err; |
1704 | } |
1705 | |
1706 | void configfs_unregister_subsystem(struct configfs_subsystem *subsys) |
1707 | { |
1708 | struct config_group *group = &subsys->su_group; |
1709 | struct dentry *dentry = group->cg_item.ci_dentry; |
1710 | |
1711 | if (dentry->d_parent != configfs_sb->s_root) { |
1712 | printk(KERN_ERR "configfs: Tried to unregister non-subsystem!\n"); |
1713 | return; |
1714 | } |
1715 | |
1716 | mutex_lock_nested(&configfs_sb->s_root->d_inode->i_mutex, |
1717 | I_MUTEX_PARENT); |
1718 | mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); |
1719 | mutex_lock(&configfs_symlink_mutex); |
1720 | spin_lock(&configfs_dirent_lock); |
1721 | if (configfs_detach_prep(dentry, NULL)) { |
1722 | printk(KERN_ERR "configfs: Tried to unregister non-empty subsystem!\n"); |
1723 | } |
1724 | spin_unlock(&configfs_dirent_lock); |
1725 | mutex_unlock(&configfs_symlink_mutex); |
1726 | configfs_detach_group(&group->cg_item); |
1727 | dentry->d_inode->i_flags |= S_DEAD; |
1728 | mutex_unlock(&dentry->d_inode->i_mutex); |
1729 | |
1730 | d_delete(dentry); |
1731 | |
1732 | mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex); |
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); |
1742 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9