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[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / configfs / dir.c
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
34 #include <linux/configfs.h>
35 #include "configfs_internal.h"
36
37 DECLARE_RWSEM(configfs_rename_sem);
38
39 static void configfs_d_iput(struct dentry * dentry,
40 struct inode * inode)
41 {
42 struct configfs_dirent * sd = dentry->d_fsdata;
43
44 if (sd) {
45 BUG_ON(sd->s_dentry != dentry);
46 sd->s_dentry = NULL;
47 configfs_put(sd);
48 }
49 iput(inode);
50 }
51
52 /*
53 * We _must_ delete our dentries on last dput, as the chain-to-parent
54 * behavior is required to clear the parents of default_groups.
55 */
56 static int configfs_d_delete(struct dentry *dentry)
57 {
58 return 1;
59 }
60
61 static struct dentry_operations configfs_dentry_ops = {
62 .d_iput = configfs_d_iput,
63 /* simple_delete_dentry() isn't exported */
64 .d_delete = configfs_d_delete,
65 };
66
67 /*
68 * Allocates a new configfs_dirent and links it to the parent configfs_dirent
69 */
70 static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent * parent_sd,
71 void * element)
72 {
73 struct configfs_dirent * sd;
74
75 sd = kmem_cache_alloc(configfs_dir_cachep, GFP_KERNEL);
76 if (!sd)
77 return NULL;
78
79 memset(sd, 0, sizeof(*sd));
80 atomic_set(&sd->s_count, 1);
81 INIT_LIST_HEAD(&sd->s_links);
82 INIT_LIST_HEAD(&sd->s_children);
83 list_add(&sd->s_sibling, &parent_sd->s_children);
84 sd->s_element = element;
85
86 return sd;
87 }
88
89 int configfs_make_dirent(struct configfs_dirent * parent_sd,
90 struct dentry * dentry, void * element,
91 umode_t mode, int type)
92 {
93 struct configfs_dirent * sd;
94
95 sd = configfs_new_dirent(parent_sd, element);
96 if (!sd)
97 return -ENOMEM;
98
99 sd->s_mode = mode;
100 sd->s_type = type;
101 sd->s_dentry = dentry;
102 if (dentry) {
103 dentry->d_fsdata = configfs_get(sd);
104 dentry->d_op = &configfs_dentry_ops;
105 }
106
107 return 0;
108 }
109
110 static int init_dir(struct inode * inode)
111 {
112 inode->i_op = &configfs_dir_inode_operations;
113 inode->i_fop = &configfs_dir_operations;
114
115 /* directory inodes start off with i_nlink == 2 (for "." entry) */
116 inode->i_nlink++;
117 return 0;
118 }
119
120 static int init_file(struct inode * inode)
121 {
122 inode->i_size = PAGE_SIZE;
123 inode->i_fop = &configfs_file_operations;
124 return 0;
125 }
126
127 static int init_symlink(struct inode * inode)
128 {
129 inode->i_op = &configfs_symlink_inode_operations;
130 return 0;
131 }
132
133 static int create_dir(struct config_item * k, struct dentry * p,
134 struct dentry * d)
135 {
136 int error;
137 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
138
139 error = configfs_make_dirent(p->d_fsdata, d, k, mode,
140 CONFIGFS_DIR);
141 if (!error) {
142 error = configfs_create(d, mode, init_dir);
143 if (!error) {
144 p->d_inode->i_nlink++;
145 (d)->d_op = &configfs_dentry_ops;
146 } else {
147 struct configfs_dirent *sd = d->d_fsdata;
148 if (sd) {
149 list_del_init(&sd->s_sibling);
150 configfs_put(sd);
151 }
152 }
153 }
154 return error;
155 }
156
157
158 /**
159 * configfs_create_dir - create a directory for an config_item.
160 * @item: config_itemwe're creating directory for.
161 * @dentry: config_item's dentry.
162 */
163
164 static int configfs_create_dir(struct config_item * item, struct dentry *dentry)
165 {
166 struct dentry * parent;
167 int error = 0;
168
169 BUG_ON(!item);
170
171 if (item->ci_parent)
172 parent = item->ci_parent->ci_dentry;
173 else if (configfs_mount && configfs_mount->mnt_sb)
174 parent = configfs_mount->mnt_sb->s_root;
175 else
176 return -EFAULT;
177
178 error = create_dir(item,parent,dentry);
179 if (!error)
180 item->ci_dentry = dentry;
181 return error;
182 }
183
184 int configfs_create_link(struct configfs_symlink *sl,
185 struct dentry *parent,
186 struct dentry *dentry)
187 {
188 int err = 0;
189 umode_t mode = S_IFLNK | S_IRWXUGO;
190
191 err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode,
192 CONFIGFS_ITEM_LINK);
193 if (!err) {
194 err = configfs_create(dentry, mode, init_symlink);
195 if (!err)
196 dentry->d_op = &configfs_dentry_ops;
197 else {
198 struct configfs_dirent *sd = dentry->d_fsdata;
199 if (sd) {
200 list_del_init(&sd->s_sibling);
201 configfs_put(sd);
202 }
203 }
204 }
205 return err;
206 }
207
208 static void remove_dir(struct dentry * d)
209 {
210 struct dentry * parent = dget(d->d_parent);
211 struct configfs_dirent * sd;
212
213 sd = d->d_fsdata;
214 list_del_init(&sd->s_sibling);
215 configfs_put(sd);
216 if (d->d_inode)
217 simple_rmdir(parent->d_inode,d);
218
219 pr_debug(" o %s removing done (%d)\n",d->d_name.name,
220 atomic_read(&d->d_count));
221
222 dput(parent);
223 }
224
225 /**
226 * configfs_remove_dir - remove an config_item's directory.
227 * @item: config_item we're removing.
228 *
229 * The only thing special about this is that we remove any files in
230 * the directory before we remove the directory, and we've inlined
231 * what used to be configfs_rmdir() below, instead of calling separately.
232 */
233
234 static void configfs_remove_dir(struct config_item * item)
235 {
236 struct dentry * dentry = dget(item->ci_dentry);
237
238 if (!dentry)
239 return;
240
241 remove_dir(dentry);
242 /**
243 * Drop reference from dget() on entrance.
244 */
245 dput(dentry);
246 }
247
248
249 /* attaches attribute's configfs_dirent to the dentry corresponding to the
250 * attribute file
251 */
252 static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry)
253 {
254 struct configfs_attribute * attr = sd->s_element;
255 int error;
256
257 dentry->d_fsdata = configfs_get(sd);
258 sd->s_dentry = dentry;
259 error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG, init_file);
260 if (error) {
261 configfs_put(sd);
262 return error;
263 }
264
265 dentry->d_op = &configfs_dentry_ops;
266 d_rehash(dentry);
267
268 return 0;
269 }
270
271 static struct dentry * configfs_lookup(struct inode *dir,
272 struct dentry *dentry,
273 struct nameidata *nd)
274 {
275 struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
276 struct configfs_dirent * sd;
277 int found = 0;
278 int err = 0;
279
280 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
281 if (sd->s_type & CONFIGFS_NOT_PINNED) {
282 const unsigned char * name = configfs_get_name(sd);
283
284 if (strcmp(name, dentry->d_name.name))
285 continue;
286
287 found = 1;
288 err = configfs_attach_attr(sd, dentry);
289 break;
290 }
291 }
292
293 if (!found) {
294 /*
295 * If it doesn't exist and it isn't a NOT_PINNED item,
296 * it must be negative.
297 */
298 return simple_lookup(dir, dentry, nd);
299 }
300
301 return ERR_PTR(err);
302 }
303
304 /*
305 * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are
306 * attributes and are removed by rmdir(). We recurse, taking i_mutex
307 * on all children that are candidates for default detach. If the
308 * result is clean, then configfs_detach_group() will handle dropping
309 * i_mutex. If there is an error, the caller will clean up the i_mutex
310 * holders via configfs_detach_rollback().
311 */
312 static int configfs_detach_prep(struct dentry *dentry)
313 {
314 struct configfs_dirent *parent_sd = dentry->d_fsdata;
315 struct configfs_dirent *sd;
316 int ret;
317
318 ret = -EBUSY;
319 if (!list_empty(&parent_sd->s_links))
320 goto out;
321
322 ret = 0;
323 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
324 if (sd->s_type & CONFIGFS_NOT_PINNED)
325 continue;
326 if (sd->s_type & CONFIGFS_USET_DEFAULT) {
327 mutex_lock(&sd->s_dentry->d_inode->i_mutex);
328 /* Mark that we've taken i_mutex */
329 sd->s_type |= CONFIGFS_USET_DROPPING;
330
331 ret = configfs_detach_prep(sd->s_dentry);
332 if (!ret)
333 continue;
334 } else
335 ret = -ENOTEMPTY;
336
337 break;
338 }
339
340 out:
341 return ret;
342 }
343
344 /*
345 * Walk the tree, dropping i_mutex wherever CONFIGFS_USET_DROPPING is
346 * set.
347 */
348 static void configfs_detach_rollback(struct dentry *dentry)
349 {
350 struct configfs_dirent *parent_sd = dentry->d_fsdata;
351 struct configfs_dirent *sd;
352
353 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
354 if (sd->s_type & CONFIGFS_USET_DEFAULT) {
355 configfs_detach_rollback(sd->s_dentry);
356
357 if (sd->s_type & CONFIGFS_USET_DROPPING) {
358 sd->s_type &= ~CONFIGFS_USET_DROPPING;
359 mutex_unlock(&sd->s_dentry->d_inode->i_mutex);
360 }
361 }
362 }
363 }
364
365 static void detach_attrs(struct config_item * item)
366 {
367 struct dentry * dentry = dget(item->ci_dentry);
368 struct configfs_dirent * parent_sd;
369 struct configfs_dirent * sd, * tmp;
370
371 if (!dentry)
372 return;
373
374 pr_debug("configfs %s: dropping attrs for dir\n",
375 dentry->d_name.name);
376
377 parent_sd = dentry->d_fsdata;
378 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
379 if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED))
380 continue;
381 list_del_init(&sd->s_sibling);
382 configfs_drop_dentry(sd, dentry);
383 configfs_put(sd);
384 }
385
386 /**
387 * Drop reference from dget() on entrance.
388 */
389 dput(dentry);
390 }
391
392 static int populate_attrs(struct config_item *item)
393 {
394 struct config_item_type *t = item->ci_type;
395 struct configfs_attribute *attr;
396 int error = 0;
397 int i;
398
399 if (!t)
400 return -EINVAL;
401 if (t->ct_attrs) {
402 for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) {
403 if ((error = configfs_create_file(item, attr)))
404 break;
405 }
406 }
407
408 if (error)
409 detach_attrs(item);
410
411 return error;
412 }
413
414 static int configfs_attach_group(struct config_item *parent_item,
415 struct config_item *item,
416 struct dentry *dentry);
417 static void configfs_detach_group(struct config_item *item);
418
419 static void detach_groups(struct config_group *group)
420 {
421 struct dentry * dentry = dget(group->cg_item.ci_dentry);
422 struct dentry *child;
423 struct configfs_dirent *parent_sd;
424 struct configfs_dirent *sd, *tmp;
425
426 if (!dentry)
427 return;
428
429 parent_sd = dentry->d_fsdata;
430 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
431 if (!sd->s_element ||
432 !(sd->s_type & CONFIGFS_USET_DEFAULT))
433 continue;
434
435 child = sd->s_dentry;
436
437 configfs_detach_group(sd->s_element);
438 child->d_inode->i_flags |= S_DEAD;
439
440 /*
441 * From rmdir/unregister, a configfs_detach_prep() pass
442 * has taken our i_mutex for us. Drop it.
443 * From mkdir/register cleanup, there is no sem held.
444 */
445 if (sd->s_type & CONFIGFS_USET_DROPPING)
446 mutex_unlock(&child->d_inode->i_mutex);
447
448 d_delete(child);
449 dput(child);
450 }
451
452 /**
453 * Drop reference from dget() on entrance.
454 */
455 dput(dentry);
456 }
457
458 /*
459 * This fakes mkdir(2) on a default_groups[] entry. It
460 * creates a dentry, attachs it, and then does fixup
461 * on the sd->s_type.
462 *
463 * We could, perhaps, tweak our parent's ->mkdir for a minute and
464 * try using vfs_mkdir. Just a thought.
465 */
466 static int create_default_group(struct config_group *parent_group,
467 struct config_group *group)
468 {
469 int ret;
470 struct qstr name;
471 struct configfs_dirent *sd;
472 /* We trust the caller holds a reference to parent */
473 struct dentry *child, *parent = parent_group->cg_item.ci_dentry;
474
475 if (!group->cg_item.ci_name)
476 group->cg_item.ci_name = group->cg_item.ci_namebuf;
477 name.name = group->cg_item.ci_name;
478 name.len = strlen(name.name);
479 name.hash = full_name_hash(name.name, name.len);
480
481 ret = -ENOMEM;
482 child = d_alloc(parent, &name);
483 if (child) {
484 d_add(child, NULL);
485
486 ret = configfs_attach_group(&parent_group->cg_item,
487 &group->cg_item, child);
488 if (!ret) {
489 sd = child->d_fsdata;
490 sd->s_type |= CONFIGFS_USET_DEFAULT;
491 } else {
492 d_delete(child);
493 dput(child);
494 }
495 }
496
497 return ret;
498 }
499
500 static int populate_groups(struct config_group *group)
501 {
502 struct config_group *new_group;
503 struct dentry *dentry = group->cg_item.ci_dentry;
504 int ret = 0;
505 int i;
506
507 if (group && group->default_groups) {
508 /* FYI, we're faking mkdir here
509 * I'm not sure we need this semaphore, as we're called
510 * from our parent's mkdir. That holds our parent's
511 * i_mutex, so afaik lookup cannot continue through our
512 * parent to find us, let alone mess with our tree.
513 * That said, taking our i_mutex is closer to mkdir
514 * emulation, and shouldn't hurt. */
515 mutex_lock(&dentry->d_inode->i_mutex);
516
517 for (i = 0; group->default_groups[i]; i++) {
518 new_group = group->default_groups[i];
519
520 ret = create_default_group(group, new_group);
521 if (ret)
522 break;
523 }
524
525 mutex_unlock(&dentry->d_inode->i_mutex);
526 }
527
528 if (ret)
529 detach_groups(group);
530
531 return ret;
532 }
533
534 /*
535 * All of link_obj/unlink_obj/link_group/unlink_group require that
536 * subsys->su_sem is held.
537 */
538
539 static void unlink_obj(struct config_item *item)
540 {
541 struct config_group *group;
542
543 group = item->ci_group;
544 if (group) {
545 list_del_init(&item->ci_entry);
546
547 item->ci_group = NULL;
548 item->ci_parent = NULL;
549 config_item_put(item);
550
551 config_group_put(group);
552 }
553 }
554
555 static void link_obj(struct config_item *parent_item, struct config_item *item)
556 {
557 /* Parent seems redundant with group, but it makes certain
558 * traversals much nicer. */
559 item->ci_parent = parent_item;
560 item->ci_group = config_group_get(to_config_group(parent_item));
561 list_add_tail(&item->ci_entry, &item->ci_group->cg_children);
562
563 config_item_get(item);
564 }
565
566 static void unlink_group(struct config_group *group)
567 {
568 int i;
569 struct config_group *new_group;
570
571 if (group->default_groups) {
572 for (i = 0; group->default_groups[i]; i++) {
573 new_group = group->default_groups[i];
574 unlink_group(new_group);
575 }
576 }
577
578 group->cg_subsys = NULL;
579 unlink_obj(&group->cg_item);
580 }
581
582 static void link_group(struct config_group *parent_group, struct config_group *group)
583 {
584 int i;
585 struct config_group *new_group;
586 struct configfs_subsystem *subsys = NULL; /* gcc is a turd */
587
588 link_obj(&parent_group->cg_item, &group->cg_item);
589
590 if (parent_group->cg_subsys)
591 subsys = parent_group->cg_subsys;
592 else if (configfs_is_root(&parent_group->cg_item))
593 subsys = to_configfs_subsystem(group);
594 else
595 BUG();
596 group->cg_subsys = subsys;
597
598 if (group->default_groups) {
599 for (i = 0; group->default_groups[i]; i++) {
600 new_group = group->default_groups[i];
601 link_group(group, new_group);
602 }
603 }
604 }
605
606 /*
607 * The goal is that configfs_attach_item() (and
608 * configfs_attach_group()) can be called from either the VFS or this
609 * module. That is, they assume that the items have been created,
610 * the dentry allocated, and the dcache is all ready to go.
611 *
612 * If they fail, they must clean up after themselves as if they
613 * had never been called. The caller (VFS or local function) will
614 * handle cleaning up the dcache bits.
615 *
616 * configfs_detach_group() and configfs_detach_item() behave similarly on
617 * the way out. They assume that the proper semaphores are held, they
618 * clean up the configfs items, and they expect their callers will
619 * handle the dcache bits.
620 */
621 static int configfs_attach_item(struct config_item *parent_item,
622 struct config_item *item,
623 struct dentry *dentry)
624 {
625 int ret;
626
627 ret = configfs_create_dir(item, dentry);
628 if (!ret) {
629 ret = populate_attrs(item);
630 if (ret) {
631 configfs_remove_dir(item);
632 d_delete(dentry);
633 }
634 }
635
636 return ret;
637 }
638
639 static void configfs_detach_item(struct config_item *item)
640 {
641 detach_attrs(item);
642 configfs_remove_dir(item);
643 }
644
645 static int configfs_attach_group(struct config_item *parent_item,
646 struct config_item *item,
647 struct dentry *dentry)
648 {
649 int ret;
650 struct configfs_dirent *sd;
651
652 ret = configfs_attach_item(parent_item, item, dentry);
653 if (!ret) {
654 sd = dentry->d_fsdata;
655 sd->s_type |= CONFIGFS_USET_DIR;
656
657 ret = populate_groups(to_config_group(item));
658 if (ret) {
659 configfs_detach_item(item);
660 d_delete(dentry);
661 }
662 }
663
664 return ret;
665 }
666
667 static void configfs_detach_group(struct config_item *item)
668 {
669 detach_groups(to_config_group(item));
670 configfs_detach_item(item);
671 }
672
673 /*
674 * Drop the initial reference from make_item()/make_group()
675 * This function assumes that reference is held on item
676 * and that item holds a valid reference to the parent. Also, it
677 * assumes the caller has validated ci_type.
678 */
679 static void client_drop_item(struct config_item *parent_item,
680 struct config_item *item)
681 {
682 struct config_item_type *type;
683
684 type = parent_item->ci_type;
685 BUG_ON(!type);
686
687 if (type->ct_group_ops && type->ct_group_ops->drop_item)
688 type->ct_group_ops->drop_item(to_config_group(parent_item),
689 item);
690 else
691 config_item_put(item);
692 }
693
694
695 static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
696 {
697 int ret;
698 struct config_group *group;
699 struct config_item *item;
700 struct config_item *parent_item;
701 struct configfs_subsystem *subsys;
702 struct configfs_dirent *sd;
703 struct config_item_type *type;
704 struct module *owner;
705 char *name;
706
707 if (dentry->d_parent == configfs_sb->s_root)
708 return -EPERM;
709
710 sd = dentry->d_parent->d_fsdata;
711 if (!(sd->s_type & CONFIGFS_USET_DIR))
712 return -EPERM;
713
714 parent_item = configfs_get_config_item(dentry->d_parent);
715 type = parent_item->ci_type;
716 subsys = to_config_group(parent_item)->cg_subsys;
717 BUG_ON(!subsys);
718
719 if (!type || !type->ct_group_ops ||
720 (!type->ct_group_ops->make_group &&
721 !type->ct_group_ops->make_item)) {
722 config_item_put(parent_item);
723 return -EPERM; /* What lack-of-mkdir returns */
724 }
725
726 name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL);
727 if (!name) {
728 config_item_put(parent_item);
729 return -ENOMEM;
730 }
731 snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name);
732
733 down(&subsys->su_sem);
734 group = NULL;
735 item = NULL;
736 if (type->ct_group_ops->make_group) {
737 group = type->ct_group_ops->make_group(to_config_group(parent_item), name);
738 if (group) {
739 link_group(to_config_group(parent_item), group);
740 item = &group->cg_item;
741 }
742 } else {
743 item = type->ct_group_ops->make_item(to_config_group(parent_item), name);
744 if (item)
745 link_obj(parent_item, item);
746 }
747 up(&subsys->su_sem);
748
749 kfree(name);
750 if (!item) {
751 config_item_put(parent_item);
752 return -ENOMEM;
753 }
754
755 ret = -EINVAL;
756 type = item->ci_type;
757 if (type) {
758 owner = type->ct_owner;
759 if (try_module_get(owner)) {
760 if (group) {
761 ret = configfs_attach_group(parent_item,
762 item,
763 dentry);
764 } else {
765 ret = configfs_attach_item(parent_item,
766 item,
767 dentry);
768 }
769
770 if (ret) {
771 down(&subsys->su_sem);
772 if (group)
773 unlink_group(group);
774 else
775 unlink_obj(item);
776 client_drop_item(parent_item, item);
777 up(&subsys->su_sem);
778
779 config_item_put(parent_item);
780 module_put(owner);
781 }
782 }
783 }
784
785 return ret;
786 }
787
788 static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
789 {
790 struct config_item *parent_item;
791 struct config_item *item;
792 struct configfs_subsystem *subsys;
793 struct configfs_dirent *sd;
794 struct module *owner = NULL;
795 int ret;
796
797 if (dentry->d_parent == configfs_sb->s_root)
798 return -EPERM;
799
800 sd = dentry->d_fsdata;
801 if (sd->s_type & CONFIGFS_USET_DEFAULT)
802 return -EPERM;
803
804 parent_item = configfs_get_config_item(dentry->d_parent);
805 subsys = to_config_group(parent_item)->cg_subsys;
806 BUG_ON(!subsys);
807
808 if (!parent_item->ci_type) {
809 config_item_put(parent_item);
810 return -EINVAL;
811 }
812
813 ret = configfs_detach_prep(dentry);
814 if (ret) {
815 configfs_detach_rollback(dentry);
816 config_item_put(parent_item);
817 return ret;
818 }
819
820 item = configfs_get_config_item(dentry);
821
822 /* Drop reference from above, item already holds one. */
823 config_item_put(parent_item);
824
825 if (item->ci_type)
826 owner = item->ci_type->ct_owner;
827
828 if (sd->s_type & CONFIGFS_USET_DIR) {
829 configfs_detach_group(item);
830
831 down(&subsys->su_sem);
832 unlink_group(to_config_group(item));
833 } else {
834 configfs_detach_item(item);
835
836 down(&subsys->su_sem);
837 unlink_obj(item);
838 }
839
840 client_drop_item(parent_item, item);
841 up(&subsys->su_sem);
842
843 /* Drop our reference from above */
844 config_item_put(item);
845
846 module_put(owner);
847
848 return 0;
849 }
850
851 struct inode_operations configfs_dir_inode_operations = {
852 .mkdir = configfs_mkdir,
853 .rmdir = configfs_rmdir,
854 .symlink = configfs_symlink,
855 .unlink = configfs_unlink,
856 .lookup = configfs_lookup,
857 .setattr = configfs_setattr,
858 };
859
860 #if 0
861 int configfs_rename_dir(struct config_item * item, const char *new_name)
862 {
863 int error = 0;
864 struct dentry * new_dentry, * parent;
865
866 if (!strcmp(config_item_name(item), new_name))
867 return -EINVAL;
868
869 if (!item->parent)
870 return -EINVAL;
871
872 down_write(&configfs_rename_sem);
873 parent = item->parent->dentry;
874
875 mutex_lock(&parent->d_inode->i_mutex);
876
877 new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
878 if (!IS_ERR(new_dentry)) {
879 if (!new_dentry->d_inode) {
880 error = config_item_set_name(item, "%s", new_name);
881 if (!error) {
882 d_add(new_dentry, NULL);
883 d_move(item->dentry, new_dentry);
884 }
885 else
886 d_delete(new_dentry);
887 } else
888 error = -EEXIST;
889 dput(new_dentry);
890 }
891 mutex_unlock(&parent->d_inode->i_mutex);
892 up_write(&configfs_rename_sem);
893
894 return error;
895 }
896 #endif
897
898 static int configfs_dir_open(struct inode *inode, struct file *file)
899 {
900 struct dentry * dentry = file->f_dentry;
901 struct configfs_dirent * parent_sd = dentry->d_fsdata;
902
903 mutex_lock(&dentry->d_inode->i_mutex);
904 file->private_data = configfs_new_dirent(parent_sd, NULL);
905 mutex_unlock(&dentry->d_inode->i_mutex);
906
907 return file->private_data ? 0 : -ENOMEM;
908
909 }
910
911 static int configfs_dir_close(struct inode *inode, struct file *file)
912 {
913 struct dentry * dentry = file->f_dentry;
914 struct configfs_dirent * cursor = file->private_data;
915
916 mutex_lock(&dentry->d_inode->i_mutex);
917 list_del_init(&cursor->s_sibling);
918 mutex_unlock(&dentry->d_inode->i_mutex);
919
920 release_configfs_dirent(cursor);
921
922 return 0;
923 }
924
925 /* Relationship between s_mode and the DT_xxx types */
926 static inline unsigned char dt_type(struct configfs_dirent *sd)
927 {
928 return (sd->s_mode >> 12) & 15;
929 }
930
931 static int configfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
932 {
933 struct dentry *dentry = filp->f_dentry;
934 struct configfs_dirent * parent_sd = dentry->d_fsdata;
935 struct configfs_dirent *cursor = filp->private_data;
936 struct list_head *p, *q = &cursor->s_sibling;
937 ino_t ino;
938 int i = filp->f_pos;
939
940 switch (i) {
941 case 0:
942 ino = dentry->d_inode->i_ino;
943 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
944 break;
945 filp->f_pos++;
946 i++;
947 /* fallthrough */
948 case 1:
949 ino = parent_ino(dentry);
950 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
951 break;
952 filp->f_pos++;
953 i++;
954 /* fallthrough */
955 default:
956 if (filp->f_pos == 2) {
957 list_del(q);
958 list_add(q, &parent_sd->s_children);
959 }
960 for (p=q->next; p!= &parent_sd->s_children; p=p->next) {
961 struct configfs_dirent *next;
962 const char * name;
963 int len;
964
965 next = list_entry(p, struct configfs_dirent,
966 s_sibling);
967 if (!next->s_element)
968 continue;
969
970 name = configfs_get_name(next);
971 len = strlen(name);
972 if (next->s_dentry)
973 ino = next->s_dentry->d_inode->i_ino;
974 else
975 ino = iunique(configfs_sb, 2);
976
977 if (filldir(dirent, name, len, filp->f_pos, ino,
978 dt_type(next)) < 0)
979 return 0;
980
981 list_del(q);
982 list_add(q, p);
983 p = q;
984 filp->f_pos++;
985 }
986 }
987 return 0;
988 }
989
990 static loff_t configfs_dir_lseek(struct file * file, loff_t offset, int origin)
991 {
992 struct dentry * dentry = file->f_dentry;
993
994 mutex_lock(&dentry->d_inode->i_mutex);
995 switch (origin) {
996 case 1:
997 offset += file->f_pos;
998 case 0:
999 if (offset >= 0)
1000 break;
1001 default:
1002 mutex_unlock(&file->f_dentry->d_inode->i_mutex);
1003 return -EINVAL;
1004 }
1005 if (offset != file->f_pos) {
1006 file->f_pos = offset;
1007 if (file->f_pos >= 2) {
1008 struct configfs_dirent *sd = dentry->d_fsdata;
1009 struct configfs_dirent *cursor = file->private_data;
1010 struct list_head *p;
1011 loff_t n = file->f_pos - 2;
1012
1013 list_del(&cursor->s_sibling);
1014 p = sd->s_children.next;
1015 while (n && p != &sd->s_children) {
1016 struct configfs_dirent *next;
1017 next = list_entry(p, struct configfs_dirent,
1018 s_sibling);
1019 if (next->s_element)
1020 n--;
1021 p = p->next;
1022 }
1023 list_add_tail(&cursor->s_sibling, p);
1024 }
1025 }
1026 mutex_unlock(&dentry->d_inode->i_mutex);
1027 return offset;
1028 }
1029
1030 const struct file_operations configfs_dir_operations = {
1031 .open = configfs_dir_open,
1032 .release = configfs_dir_close,
1033 .llseek = configfs_dir_lseek,
1034 .read = generic_read_dir,
1035 .readdir = configfs_readdir,
1036 };
1037
1038 int configfs_register_subsystem(struct configfs_subsystem *subsys)
1039 {
1040 int err;
1041 struct config_group *group = &subsys->su_group;
1042 struct qstr name;
1043 struct dentry *dentry;
1044 struct configfs_dirent *sd;
1045
1046 err = configfs_pin_fs();
1047 if (err)
1048 return err;
1049
1050 if (!group->cg_item.ci_name)
1051 group->cg_item.ci_name = group->cg_item.ci_namebuf;
1052
1053 sd = configfs_sb->s_root->d_fsdata;
1054 link_group(to_config_group(sd->s_element), group);
1055
1056 mutex_lock(&configfs_sb->s_root->d_inode->i_mutex);
1057
1058 name.name = group->cg_item.ci_name;
1059 name.len = strlen(name.name);
1060 name.hash = full_name_hash(name.name, name.len);
1061
1062 err = -ENOMEM;
1063 dentry = d_alloc(configfs_sb->s_root, &name);
1064 if (!dentry)
1065 goto out_release;
1066
1067 d_add(dentry, NULL);
1068
1069 err = configfs_attach_group(sd->s_element, &group->cg_item,
1070 dentry);
1071 if (!err)
1072 dentry = NULL;
1073 else
1074 d_delete(dentry);
1075
1076 mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
1077
1078 if (dentry) {
1079 dput(dentry);
1080 out_release:
1081 unlink_group(group);
1082 configfs_release_fs();
1083 }
1084
1085 return err;
1086 }
1087
1088 void configfs_unregister_subsystem(struct configfs_subsystem *subsys)
1089 {
1090 struct config_group *group = &subsys->su_group;
1091 struct dentry *dentry = group->cg_item.ci_dentry;
1092
1093 if (dentry->d_parent != configfs_sb->s_root) {
1094 printk(KERN_ERR "configfs: Tried to unregister non-subsystem!\n");
1095 return;
1096 }
1097
1098 mutex_lock(&configfs_sb->s_root->d_inode->i_mutex);
1099 mutex_lock(&dentry->d_inode->i_mutex);
1100 if (configfs_detach_prep(dentry)) {
1101 printk(KERN_ERR "configfs: Tried to unregister non-empty subsystem!\n");
1102 }
1103 configfs_detach_group(&group->cg_item);
1104 dentry->d_inode->i_flags |= S_DEAD;
1105 mutex_unlock(&dentry->d_inode->i_mutex);
1106
1107 d_delete(dentry);
1108
1109 mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
1110
1111 dput(dentry);
1112
1113 unlink_group(group);
1114 configfs_release_fs();
1115 }
1116
1117 EXPORT_SYMBOL(configfs_register_subsystem);
1118 EXPORT_SYMBOL(configfs_unregister_subsystem);
kernel source for telekom puls (alcatel/mediatek)