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-rw-r--r--fs/configfs/dir.c1102
1 files changed, 1102 insertions, 0 deletions
diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
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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
37DECLARE_RWSEM(configfs_rename_sem);
38
39static 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 */
56static int configfs_d_delete(struct dentry *dentry)
57{
58 return 1;
59}
60
61static 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 */
70static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent * parent_sd,
71 void * element)
72{
73 struct configfs_dirent * sd;
74
75 sd = kmalloc(sizeof(*sd), 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
89int 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
110static 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
120static 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
127static int init_symlink(struct inode * inode)
128{
129 inode->i_op = &configfs_symlink_inode_operations;
130 return 0;
131}
132
133static 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_create(d, mode, init_dir);
140 if (!error) {
141 error = configfs_make_dirent(p->d_fsdata, d, k, mode,
142 CONFIGFS_DIR);
143 if (!error) {
144 p->d_inode->i_nlink++;
145 (d)->d_op = &configfs_dentry_ops;
146 }
147 }
148 return error;
149}
150
151
152/**
153 * configfs_create_dir - create a directory for an config_item.
154 * @item: config_itemwe're creating directory for.
155 * @dentry: config_item's dentry.
156 */
157
158static int configfs_create_dir(struct config_item * item, struct dentry *dentry)
159{
160 struct dentry * parent;
161 int error = 0;
162
163 BUG_ON(!item);
164
165 if (item->ci_parent)
166 parent = item->ci_parent->ci_dentry;
167 else if (configfs_mount && configfs_mount->mnt_sb)
168 parent = configfs_mount->mnt_sb->s_root;
169 else
170 return -EFAULT;
171
172 error = create_dir(item,parent,dentry);
173 if (!error)
174 item->ci_dentry = dentry;
175 return error;
176}
177
178int configfs_create_link(struct configfs_symlink *sl,
179 struct dentry *parent,
180 struct dentry *dentry)
181{
182 int err = 0;
183 umode_t mode = S_IFLNK | S_IRWXUGO;
184
185 err = configfs_create(dentry, mode, init_symlink);
186 if (!err) {
187 err = configfs_make_dirent(parent->d_fsdata, dentry, sl,
188 mode, CONFIGFS_ITEM_LINK);
189 if (!err)
190 dentry->d_op = &configfs_dentry_ops;
191 }
192 return err;
193}
194
195static void remove_dir(struct dentry * d)
196{
197 struct dentry * parent = dget(d->d_parent);
198 struct configfs_dirent * sd;
199
200 sd = d->d_fsdata;
201 list_del_init(&sd->s_sibling);
202 configfs_put(sd);
203 if (d->d_inode)
204 simple_rmdir(parent->d_inode,d);
205
206 pr_debug(" o %s removing done (%d)\n",d->d_name.name,
207 atomic_read(&d->d_count));
208
209 dput(parent);
210}
211
212/**
213 * configfs_remove_dir - remove an config_item's directory.
214 * @item: config_item we're removing.
215 *
216 * The only thing special about this is that we remove any files in
217 * the directory before we remove the directory, and we've inlined
218 * what used to be configfs_rmdir() below, instead of calling separately.
219 */
220
221static void configfs_remove_dir(struct config_item * item)
222{
223 struct dentry * dentry = dget(item->ci_dentry);
224
225 if (!dentry)
226 return;
227
228 remove_dir(dentry);
229 /**
230 * Drop reference from dget() on entrance.
231 */
232 dput(dentry);
233}
234
235
236/* attaches attribute's configfs_dirent to the dentry corresponding to the
237 * attribute file
238 */
239static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry)
240{
241 struct configfs_attribute * attr = sd->s_element;
242 int error;
243
244 error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG, init_file);
245 if (error)
246 return error;
247
248 dentry->d_op = &configfs_dentry_ops;
249 dentry->d_fsdata = configfs_get(sd);
250 sd->s_dentry = dentry;
251 d_rehash(dentry);
252
253 return 0;
254}
255
256static struct dentry * configfs_lookup(struct inode *dir,
257 struct dentry *dentry,
258 struct nameidata *nd)
259{
260 struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
261 struct configfs_dirent * sd;
262 int found = 0;
263 int err = 0;
264
265 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
266 if (sd->s_type & CONFIGFS_NOT_PINNED) {
267 const unsigned char * name = configfs_get_name(sd);
268
269 if (strcmp(name, dentry->d_name.name))
270 continue;
271
272 found = 1;
273 err = configfs_attach_attr(sd, dentry);
274 break;
275 }
276 }
277
278 if (!found) {
279 /*
280 * If it doesn't exist and it isn't a NOT_PINNED item,
281 * it must be negative.
282 */
283 return simple_lookup(dir, dentry, nd);
284 }
285
286 return ERR_PTR(err);
287}
288
289/*
290 * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are
291 * attributes and are removed by rmdir(). We recurse, taking i_mutex
292 * on all children that are candidates for default detach. If the
293 * result is clean, then configfs_detach_group() will handle dropping
294 * i_mutex. If there is an error, the caller will clean up the i_mutex
295 * holders via configfs_detach_rollback().
296 */
297static int configfs_detach_prep(struct dentry *dentry)
298{
299 struct configfs_dirent *parent_sd = dentry->d_fsdata;
300 struct configfs_dirent *sd;
301 int ret;
302
303 ret = -EBUSY;
304 if (!list_empty(&parent_sd->s_links))
305 goto out;
306
307 ret = 0;
308 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
309 if (sd->s_type & CONFIGFS_NOT_PINNED)
310 continue;
311 if (sd->s_type & CONFIGFS_USET_DEFAULT) {
312 mutex_lock(&sd->s_dentry->d_inode->i_mutex);
313 /* Mark that we've taken i_mutex */
314 sd->s_type |= CONFIGFS_USET_DROPPING;
315
316 ret = configfs_detach_prep(sd->s_dentry);
317 if (!ret)
318 continue;
319 } else
320 ret = -ENOTEMPTY;
321
322 break;
323 }
324
325out:
326 return ret;
327}
328
329/*
330 * Walk the tree, dropping i_mutex wherever CONFIGFS_USET_DROPPING is
331 * set.
332 */
333static void configfs_detach_rollback(struct dentry *dentry)
334{
335 struct configfs_dirent *parent_sd = dentry->d_fsdata;
336 struct configfs_dirent *sd;
337
338 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
339 if (sd->s_type & CONFIGFS_USET_DEFAULT) {
340 configfs_detach_rollback(sd->s_dentry);
341
342 if (sd->s_type & CONFIGFS_USET_DROPPING) {
343 sd->s_type &= ~CONFIGFS_USET_DROPPING;
344 mutex_unlock(&sd->s_dentry->d_inode->i_mutex);
345 }
346 }
347 }
348}
349
350static void detach_attrs(struct config_item * item)
351{
352 struct dentry * dentry = dget(item->ci_dentry);
353 struct configfs_dirent * parent_sd;
354 struct configfs_dirent * sd, * tmp;
355
356 if (!dentry)
357 return;
358
359 pr_debug("configfs %s: dropping attrs for dir\n",
360 dentry->d_name.name);
361
362 parent_sd = dentry->d_fsdata;
363 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
364 if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED))
365 continue;
366 list_del_init(&sd->s_sibling);
367 configfs_drop_dentry(sd, dentry);
368 configfs_put(sd);
369 }
370
371 /**
372 * Drop reference from dget() on entrance.
373 */
374 dput(dentry);
375}
376
377static int populate_attrs(struct config_item *item)
378{
379 struct config_item_type *t = item->ci_type;
380 struct configfs_attribute *attr;
381 int error = 0;
382 int i;
383
384 if (!t)
385 return -EINVAL;
386 if (t->ct_attrs) {
387 for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) {
388 if ((error = configfs_create_file(item, attr)))
389 break;
390 }
391 }
392
393 if (error)
394 detach_attrs(item);
395
396 return error;
397}
398
399static int configfs_attach_group(struct config_item *parent_item,
400 struct config_item *item,
401 struct dentry *dentry);
402static void configfs_detach_group(struct config_item *item);
403
404static void detach_groups(struct config_group *group)
405{
406 struct dentry * dentry = dget(group->cg_item.ci_dentry);
407 struct dentry *child;
408 struct configfs_dirent *parent_sd;
409 struct configfs_dirent *sd, *tmp;
410
411 if (!dentry)
412 return;
413
414 parent_sd = dentry->d_fsdata;
415 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
416 if (!sd->s_element ||
417 !(sd->s_type & CONFIGFS_USET_DEFAULT))
418 continue;
419
420 child = sd->s_dentry;
421
422 configfs_detach_group(sd->s_element);
423 child->d_inode->i_flags |= S_DEAD;
424
425 /*
426 * From rmdir/unregister, a configfs_detach_prep() pass
427 * has taken our i_mutex for us. Drop it.
428 * From mkdir/register cleanup, there is no sem held.
429 */
430 if (sd->s_type & CONFIGFS_USET_DROPPING)
431 mutex_unlock(&child->d_inode->i_mutex);
432
433 d_delete(child);
434 dput(child);
435 }
436
437 /**
438 * Drop reference from dget() on entrance.
439 */
440 dput(dentry);
441}
442
443/*
444 * This fakes mkdir(2) on a default_groups[] entry. It
445 * creates a dentry, attachs it, and then does fixup
446 * on the sd->s_type.
447 *
448 * We could, perhaps, tweak our parent's ->mkdir for a minute and
449 * try using vfs_mkdir. Just a thought.
450 */
451static int create_default_group(struct config_group *parent_group,
452 struct config_group *group)
453{
454 int ret;
455 struct qstr name;
456 struct configfs_dirent *sd;
457 /* We trust the caller holds a reference to parent */
458 struct dentry *child, *parent = parent_group->cg_item.ci_dentry;
459
460 if (!group->cg_item.ci_name)
461 group->cg_item.ci_name = group->cg_item.ci_namebuf;
462 name.name = group->cg_item.ci_name;
463 name.len = strlen(name.name);
464 name.hash = full_name_hash(name.name, name.len);
465
466 ret = -ENOMEM;
467 child = d_alloc(parent, &name);
468 if (child) {
469 d_add(child, NULL);
470
471 ret = configfs_attach_group(&parent_group->cg_item,
472 &group->cg_item, child);
473 if (!ret) {
474 sd = child->d_fsdata;
475 sd->s_type |= CONFIGFS_USET_DEFAULT;
476 } else {
477 d_delete(child);
478 dput(child);
479 }
480 }
481
482 return ret;
483}
484
485static int populate_groups(struct config_group *group)
486{
487 struct config_group *new_group;
488 struct dentry *dentry = group->cg_item.ci_dentry;
489 int ret = 0;
490 int i;
491
492 if (group && group->default_groups) {
493 /* FYI, we're faking mkdir here
494 * I'm not sure we need this semaphore, as we're called
495 * from our parent's mkdir. That holds our parent's
496 * i_mutex, so afaik lookup cannot continue through our
497 * parent to find us, let alone mess with our tree.
498 * That said, taking our i_mutex is closer to mkdir
499 * emulation, and shouldn't hurt. */
500 mutex_lock(&dentry->d_inode->i_mutex);
501
502 for (i = 0; group->default_groups[i]; i++) {
503 new_group = group->default_groups[i];
504
505 ret = create_default_group(group, new_group);
506 if (ret)
507 break;
508 }
509
510 mutex_unlock(&dentry->d_inode->i_mutex);
511 }
512
513 if (ret)
514 detach_groups(group);
515
516 return ret;
517}
518
519/*
520 * All of link_obj/unlink_obj/link_group/unlink_group require that
521 * subsys->su_sem is held.
522 */
523
524static void unlink_obj(struct config_item *item)
525{
526 struct config_group *group;
527
528 group = item->ci_group;
529 if (group) {
530 list_del_init(&item->ci_entry);
531
532 item->ci_group = NULL;
533 item->ci_parent = NULL;
534 config_item_put(item);
535
536 config_group_put(group);
537 }
538}
539
540static void link_obj(struct config_item *parent_item, struct config_item *item)
541{
542 /* Parent seems redundant with group, but it makes certain
543 * traversals much nicer. */
544 item->ci_parent = parent_item;
545 item->ci_group = config_group_get(to_config_group(parent_item));
546 list_add_tail(&item->ci_entry, &item->ci_group->cg_children);
547
548 config_item_get(item);
549}
550
551static void unlink_group(struct config_group *group)
552{
553 int i;
554 struct config_group *new_group;
555
556 if (group->default_groups) {
557 for (i = 0; group->default_groups[i]; i++) {
558 new_group = group->default_groups[i];
559 unlink_group(new_group);
560 }
561 }
562
563 group->cg_subsys = NULL;
564 unlink_obj(&group->cg_item);
565}
566
567static void link_group(struct config_group *parent_group, struct config_group *group)
568{
569 int i;
570 struct config_group *new_group;
571 struct configfs_subsystem *subsys = NULL; /* gcc is a turd */
572
573 link_obj(&parent_group->cg_item, &group->cg_item);
574
575 if (parent_group->cg_subsys)
576 subsys = parent_group->cg_subsys;
577 else if (configfs_is_root(&parent_group->cg_item))
578 subsys = to_configfs_subsystem(group);
579 else
580 BUG();
581 group->cg_subsys = subsys;
582
583 if (group->default_groups) {
584 for (i = 0; group->default_groups[i]; i++) {
585 new_group = group->default_groups[i];
586 link_group(group, new_group);
587 }
588 }
589}
590
591/*
592 * The goal is that configfs_attach_item() (and
593 * configfs_attach_group()) can be called from either the VFS or this
594 * module. That is, they assume that the items have been created,
595 * the dentry allocated, and the dcache is all ready to go.
596 *
597 * If they fail, they must clean up after themselves as if they
598 * had never been called. The caller (VFS or local function) will
599 * handle cleaning up the dcache bits.
600 *
601 * configfs_detach_group() and configfs_detach_item() behave similarly on
602 * the way out. They assume that the proper semaphores are held, they
603 * clean up the configfs items, and they expect their callers will
604 * handle the dcache bits.
605 */
606static int configfs_attach_item(struct config_item *parent_item,
607 struct config_item *item,
608 struct dentry *dentry)
609{
610 int ret;
611
612 ret = configfs_create_dir(item, dentry);
613 if (!ret) {
614 ret = populate_attrs(item);
615 if (ret) {
616 configfs_remove_dir(item);
617 d_delete(dentry);
618 }
619 }
620
621 return ret;
622}
623
624static void configfs_detach_item(struct config_item *item)
625{
626 detach_attrs(item);
627 configfs_remove_dir(item);
628}
629
630static int configfs_attach_group(struct config_item *parent_item,
631 struct config_item *item,
632 struct dentry *dentry)
633{
634 int ret;
635 struct configfs_dirent *sd;
636
637 ret = configfs_attach_item(parent_item, item, dentry);
638 if (!ret) {
639 sd = dentry->d_fsdata;
640 sd->s_type |= CONFIGFS_USET_DIR;
641
642 ret = populate_groups(to_config_group(item));
643 if (ret) {
644 configfs_detach_item(item);
645 d_delete(dentry);
646 }
647 }
648
649 return ret;
650}
651
652static void configfs_detach_group(struct config_item *item)
653{
654 detach_groups(to_config_group(item));
655 configfs_detach_item(item);
656}
657
658/*
659 * Drop the initial reference from make_item()/make_group()
660 * This function assumes that reference is held on item
661 * and that item holds a valid reference to the parent. Also, it
662 * assumes the caller has validated ci_type.
663 */
664static void client_drop_item(struct config_item *parent_item,
665 struct config_item *item)
666{
667 struct config_item_type *type;
668
669 type = parent_item->ci_type;
670 BUG_ON(!type);
671
672 if (type->ct_group_ops && type->ct_group_ops->drop_item)
673 type->ct_group_ops->drop_item(to_config_group(parent_item),
674 item);
675 else
676 config_item_put(item);
677}
678
679
680static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
681{
682 int ret;
683 struct config_group *group;
684 struct config_item *item;
685 struct config_item *parent_item;
686 struct configfs_subsystem *subsys;
687 struct configfs_dirent *sd;
688 struct config_item_type *type;
689 struct module *owner;
690 char *name;
691
692 if (dentry->d_parent == configfs_sb->s_root)
693 return -EPERM;
694
695 sd = dentry->d_parent->d_fsdata;
696 if (!(sd->s_type & CONFIGFS_USET_DIR))
697 return -EPERM;
698
699 parent_item = configfs_get_config_item(dentry->d_parent);
700 type = parent_item->ci_type;
701 subsys = to_config_group(parent_item)->cg_subsys;
702 BUG_ON(!subsys);
703
704 if (!type || !type->ct_group_ops ||
705 (!type->ct_group_ops->make_group &&
706 !type->ct_group_ops->make_item)) {
707 config_item_put(parent_item);
708 return -EPERM; /* What lack-of-mkdir returns */
709 }
710
711 name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL);
712 if (!name) {
713 config_item_put(parent_item);
714 return -ENOMEM;
715 }
716 snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name);
717
718 down(&subsys->su_sem);
719 group = NULL;
720 item = NULL;
721 if (type->ct_group_ops->make_group) {
722 group = type->ct_group_ops->make_group(to_config_group(parent_item), name);
723 if (group) {
724 link_group(to_config_group(parent_item), group);
725 item = &group->cg_item;
726 }
727 } else {
728 item = type->ct_group_ops->make_item(to_config_group(parent_item), name);
729 if (item)
730 link_obj(parent_item, item);
731 }
732 up(&subsys->su_sem);
733
734 kfree(name);
735 if (!item) {
736 config_item_put(parent_item);
737 return -ENOMEM;
738 }
739
740 ret = -EINVAL;
741 type = item->ci_type;
742 if (type) {
743 owner = type->ct_owner;
744 if (try_module_get(owner)) {
745 if (group) {
746 ret = configfs_attach_group(parent_item,
747 item,
748 dentry);
749 } else {
750 ret = configfs_attach_item(parent_item,
751 item,
752 dentry);
753 }
754
755 if (ret) {
756 down(&subsys->su_sem);
757 if (group)
758 unlink_group(group);
759 else
760 unlink_obj(item);
761 client_drop_item(parent_item, item);
762 up(&subsys->su_sem);
763
764 config_item_put(parent_item);
765 module_put(owner);
766 }
767 }
768 }
769
770 return ret;
771}
772
773static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
774{
775 struct config_item *parent_item;
776 struct config_item *item;
777 struct configfs_subsystem *subsys;
778 struct configfs_dirent *sd;
779 struct module *owner = NULL;
780 int ret;
781
782 if (dentry->d_parent == configfs_sb->s_root)
783 return -EPERM;
784
785 sd = dentry->d_fsdata;
786 if (sd->s_type & CONFIGFS_USET_DEFAULT)
787 return -EPERM;
788
789 parent_item = configfs_get_config_item(dentry->d_parent);
790 subsys = to_config_group(parent_item)->cg_subsys;
791 BUG_ON(!subsys);
792
793 if (!parent_item->ci_type) {
794 config_item_put(parent_item);
795 return -EINVAL;
796 }
797
798 ret = configfs_detach_prep(dentry);
799 if (ret) {
800 configfs_detach_rollback(dentry);
801 config_item_put(parent_item);
802 return ret;
803 }
804
805 item = configfs_get_config_item(dentry);
806
807 /* Drop reference from above, item already holds one. */
808 config_item_put(parent_item);
809
810 if (item->ci_type)
811 owner = item->ci_type->ct_owner;
812
813 if (sd->s_type & CONFIGFS_USET_DIR) {
814 configfs_detach_group(item);
815
816 down(&subsys->su_sem);
817 unlink_group(to_config_group(item));
818 } else {
819 configfs_detach_item(item);
820
821 down(&subsys->su_sem);
822 unlink_obj(item);
823 }
824
825 client_drop_item(parent_item, item);
826 up(&subsys->su_sem);
827
828 /* Drop our reference from above */
829 config_item_put(item);
830
831 module_put(owner);
832
833 return 0;
834}
835
836struct inode_operations configfs_dir_inode_operations = {
837 .mkdir = configfs_mkdir,
838 .rmdir = configfs_rmdir,
839 .symlink = configfs_symlink,
840 .unlink = configfs_unlink,
841 .lookup = configfs_lookup,
842};
843
844#if 0
845int configfs_rename_dir(struct config_item * item, const char *new_name)
846{
847 int error = 0;
848 struct dentry * new_dentry, * parent;
849
850 if (!strcmp(config_item_name(item), new_name))
851 return -EINVAL;
852
853 if (!item->parent)
854 return -EINVAL;
855
856 down_write(&configfs_rename_sem);
857 parent = item->parent->dentry;
858
859 mutex_lock(&parent->d_inode->i_mutex);
860
861 new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
862 if (!IS_ERR(new_dentry)) {
863 if (!new_dentry->d_inode) {
864 error = config_item_set_name(item, "%s", new_name);
865 if (!error) {
866 d_add(new_dentry, NULL);
867 d_move(item->dentry, new_dentry);
868 }
869 else
870 d_delete(new_dentry);
871 } else
872 error = -EEXIST;
873 dput(new_dentry);
874 }
875 mutex_unlock(&parent->d_inode->i_mutex);
876 up_write(&configfs_rename_sem);
877
878 return error;
879}
880#endif
881
882static int configfs_dir_open(struct inode *inode, struct file *file)
883{
884 struct dentry * dentry = file->f_dentry;
885 struct configfs_dirent * parent_sd = dentry->d_fsdata;
886
887 mutex_lock(&dentry->d_inode->i_mutex);
888 file->private_data = configfs_new_dirent(parent_sd, NULL);
889 mutex_unlock(&dentry->d_inode->i_mutex);
890
891 return file->private_data ? 0 : -ENOMEM;
892
893}
894
895static int configfs_dir_close(struct inode *inode, struct file *file)
896{
897 struct dentry * dentry = file->f_dentry;
898 struct configfs_dirent * cursor = file->private_data;
899
900 mutex_lock(&dentry->d_inode->i_mutex);
901 list_del_init(&cursor->s_sibling);
902 mutex_unlock(&dentry->d_inode->i_mutex);
903
904 release_configfs_dirent(cursor);
905
906 return 0;
907}
908
909/* Relationship between s_mode and the DT_xxx types */
910static inline unsigned char dt_type(struct configfs_dirent *sd)
911{
912 return (sd->s_mode >> 12) & 15;
913}
914
915static int configfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
916{
917 struct dentry *dentry = filp->f_dentry;
918 struct configfs_dirent * parent_sd = dentry->d_fsdata;
919 struct configfs_dirent *cursor = filp->private_data;
920 struct list_head *p, *q = &cursor->s_sibling;
921 ino_t ino;
922 int i = filp->f_pos;
923
924 switch (i) {
925 case 0:
926 ino = dentry->d_inode->i_ino;
927 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
928 break;
929 filp->f_pos++;
930 i++;
931 /* fallthrough */
932 case 1:
933 ino = parent_ino(dentry);
934 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
935 break;
936 filp->f_pos++;
937 i++;
938 /* fallthrough */
939 default:
940 if (filp->f_pos == 2) {
941 list_del(q);
942 list_add(q, &parent_sd->s_children);
943 }
944 for (p=q->next; p!= &parent_sd->s_children; p=p->next) {
945 struct configfs_dirent *next;
946 const char * name;
947 int len;
948
949 next = list_entry(p, struct configfs_dirent,
950 s_sibling);
951 if (!next->s_element)
952 continue;
953
954 name = configfs_get_name(next);
955 len = strlen(name);
956 if (next->s_dentry)
957 ino = next->s_dentry->d_inode->i_ino;
958 else
959 ino = iunique(configfs_sb, 2);
960
961 if (filldir(dirent, name, len, filp->f_pos, ino,
962 dt_type(next)) < 0)
963 return 0;
964
965 list_del(q);
966 list_add(q, p);
967 p = q;
968 filp->f_pos++;
969 }
970 }
971 return 0;
972}
973
974static loff_t configfs_dir_lseek(struct file * file, loff_t offset, int origin)
975{
976 struct dentry * dentry = file->f_dentry;
977
978 mutex_lock(&dentry->d_inode->i_mutex);
979 switch (origin) {
980 case 1:
981 offset += file->f_pos;
982 case 0:
983 if (offset >= 0)
984 break;
985 default:
986 mutex_unlock(&file->f_dentry->d_inode->i_mutex);
987 return -EINVAL;
988 }
989 if (offset != file->f_pos) {
990 file->f_pos = offset;
991 if (file->f_pos >= 2) {
992 struct configfs_dirent *sd = dentry->d_fsdata;
993 struct configfs_dirent *cursor = file->private_data;
994 struct list_head *p;
995 loff_t n = file->f_pos - 2;
996
997 list_del(&cursor->s_sibling);
998 p = sd->s_children.next;
999 while (n && p != &sd->s_children) {
1000 struct configfs_dirent *next;
1001 next = list_entry(p, struct configfs_dirent,
1002 s_sibling);
1003 if (next->s_element)
1004 n--;
1005 p = p->next;
1006 }
1007 list_add_tail(&cursor->s_sibling, p);
1008 }
1009 }
1010 mutex_unlock(&dentry->d_inode->i_mutex);
1011 return offset;
1012}
1013
1014struct file_operations configfs_dir_operations = {
1015 .open = configfs_dir_open,
1016 .release = configfs_dir_close,
1017 .llseek = configfs_dir_lseek,
1018 .read = generic_read_dir,
1019 .readdir = configfs_readdir,
1020};
1021
1022int configfs_register_subsystem(struct configfs_subsystem *subsys)
1023{
1024 int err;
1025 struct config_group *group = &subsys->su_group;
1026 struct qstr name;
1027 struct dentry *dentry;
1028 struct configfs_dirent *sd;
1029
1030 err = configfs_pin_fs();
1031 if (err)
1032 return err;
1033
1034 if (!group->cg_item.ci_name)
1035 group->cg_item.ci_name = group->cg_item.ci_namebuf;
1036
1037 sd = configfs_sb->s_root->d_fsdata;
1038 link_group(to_config_group(sd->s_element), group);
1039
1040 mutex_lock(&configfs_sb->s_root->d_inode->i_mutex);
1041
1042 name.name = group->cg_item.ci_name;
1043 name.len = strlen(name.name);
1044 name.hash = full_name_hash(name.name, name.len);
1045
1046 err = -ENOMEM;
1047 dentry = d_alloc(configfs_sb->s_root, &name);
1048 if (!dentry)
1049 goto out_release;
1050
1051 d_add(dentry, NULL);
1052
1053 err = configfs_attach_group(sd->s_element, &group->cg_item,
1054 dentry);
1055 if (!err)
1056 dentry = NULL;
1057 else
1058 d_delete(dentry);
1059
1060 mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
1061
1062 if (dentry) {
1063 dput(dentry);
1064out_release:
1065 unlink_group(group);
1066 configfs_release_fs();
1067 }
1068
1069 return err;
1070}
1071
1072void configfs_unregister_subsystem(struct configfs_subsystem *subsys)
1073{
1074 struct config_group *group = &subsys->su_group;
1075 struct dentry *dentry = group->cg_item.ci_dentry;
1076
1077 if (dentry->d_parent != configfs_sb->s_root) {
1078 printk(KERN_ERR "configfs: Tried to unregister non-subsystem!\n");
1079 return;
1080 }
1081
1082 mutex_lock(&configfs_sb->s_root->d_inode->i_mutex);
1083 mutex_lock(&dentry->d_inode->i_mutex);
1084 if (configfs_detach_prep(dentry)) {
1085 printk(KERN_ERR "configfs: Tried to unregister non-empty subsystem!\n");
1086 }
1087 configfs_detach_group(&group->cg_item);
1088 dentry->d_inode->i_flags |= S_DEAD;
1089 mutex_unlock(&dentry->d_inode->i_mutex);
1090
1091 d_delete(dentry);
1092
1093 mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
1094
1095 dput(dentry);
1096
1097 unlink_group(group);
1098 configfs_release_fs();
1099}
1100
1101EXPORT_SYMBOL(configfs_register_subsystem);
1102EXPORT_SYMBOL(configfs_unregister_subsystem);
generated by cgit v1.2.2 (git 2.25.0) at 2025-11-01 07:17:31 -0400