blob: a48dc7dd8765399936cd8c1fbd7fe80d7949e68c [file] [log] [blame]
Joel Becker7063fbf2005-12-15 14:29:43 -08001/* -*- 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
Robert P. J. Dayc3762222007-02-10 01:45:03 -080075 sd = kmem_cache_zalloc(configfs_dir_cachep, GFP_KERNEL);
Joel Becker7063fbf2005-12-15 14:29:43 -080076 if (!sd)
77 return NULL;
78
Joel Becker7063fbf2005-12-15 14:29:43 -080079 atomic_set(&sd->s_count, 1);
80 INIT_LIST_HEAD(&sd->s_links);
81 INIT_LIST_HEAD(&sd->s_children);
82 list_add(&sd->s_sibling, &parent_sd->s_children);
83 sd->s_element = element;
84
85 return sd;
86}
87
Joel Beckerb4c98f62006-09-13 11:01:19 -070088/*
89 *
90 * Return -EEXIST if there is already a configfs element with the same
91 * name for the same parent.
92 *
93 * called with parent inode's i_mutex held
94 */
Adrian Bunk58d206c2006-11-20 03:24:00 +010095static int configfs_dirent_exists(struct configfs_dirent *parent_sd,
96 const unsigned char *new)
Joel Beckerb4c98f62006-09-13 11:01:19 -070097{
98 struct configfs_dirent * sd;
99
100 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
101 if (sd->s_element) {
102 const unsigned char *existing = configfs_get_name(sd);
103 if (strcmp(existing, new))
104 continue;
105 else
106 return -EEXIST;
107 }
108 }
109
110 return 0;
111}
112
113
Joel Becker7063fbf2005-12-15 14:29:43 -0800114int configfs_make_dirent(struct configfs_dirent * parent_sd,
115 struct dentry * dentry, void * element,
116 umode_t mode, int type)
117{
118 struct configfs_dirent * sd;
119
120 sd = configfs_new_dirent(parent_sd, element);
121 if (!sd)
122 return -ENOMEM;
123
124 sd->s_mode = mode;
125 sd->s_type = type;
126 sd->s_dentry = dentry;
127 if (dentry) {
128 dentry->d_fsdata = configfs_get(sd);
129 dentry->d_op = &configfs_dentry_ops;
130 }
131
132 return 0;
133}
134
135static int init_dir(struct inode * inode)
136{
137 inode->i_op = &configfs_dir_inode_operations;
138 inode->i_fop = &configfs_dir_operations;
139
140 /* directory inodes start off with i_nlink == 2 (for "." entry) */
Dave Hansend8c76e62006-09-30 23:29:04 -0700141 inc_nlink(inode);
Joel Becker7063fbf2005-12-15 14:29:43 -0800142 return 0;
143}
144
Dave Hansence8d2cd2007-10-16 23:31:13 -0700145static int configfs_init_file(struct inode * inode)
Joel Becker7063fbf2005-12-15 14:29:43 -0800146{
147 inode->i_size = PAGE_SIZE;
148 inode->i_fop = &configfs_file_operations;
149 return 0;
150}
151
152static int init_symlink(struct inode * inode)
153{
154 inode->i_op = &configfs_symlink_inode_operations;
155 return 0;
156}
157
158static int create_dir(struct config_item * k, struct dentry * p,
159 struct dentry * d)
160{
161 int error;
162 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
163
Joel Beckerb4c98f62006-09-13 11:01:19 -0700164 error = configfs_dirent_exists(p->d_fsdata, d->d_name.name);
165 if (!error)
166 error = configfs_make_dirent(p->d_fsdata, d, k, mode,
167 CONFIGFS_DIR);
Joel Becker7063fbf2005-12-15 14:29:43 -0800168 if (!error) {
Joel Becker3d0f89b2006-01-25 13:31:07 -0800169 error = configfs_create(d, mode, init_dir);
Joel Becker7063fbf2005-12-15 14:29:43 -0800170 if (!error) {
Dave Hansend8c76e62006-09-30 23:29:04 -0700171 inc_nlink(p->d_inode);
Joel Becker7063fbf2005-12-15 14:29:43 -0800172 (d)->d_op = &configfs_dentry_ops;
Joel Becker3d0f89b2006-01-25 13:31:07 -0800173 } else {
174 struct configfs_dirent *sd = d->d_fsdata;
175 if (sd) {
176 list_del_init(&sd->s_sibling);
177 configfs_put(sd);
178 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800179 }
180 }
181 return error;
182}
183
184
185/**
186 * configfs_create_dir - create a directory for an config_item.
187 * @item: config_itemwe're creating directory for.
188 * @dentry: config_item's dentry.
189 */
190
191static int configfs_create_dir(struct config_item * item, struct dentry *dentry)
192{
193 struct dentry * parent;
194 int error = 0;
195
196 BUG_ON(!item);
197
198 if (item->ci_parent)
199 parent = item->ci_parent->ci_dentry;
200 else if (configfs_mount && configfs_mount->mnt_sb)
201 parent = configfs_mount->mnt_sb->s_root;
202 else
203 return -EFAULT;
204
205 error = create_dir(item,parent,dentry);
206 if (!error)
207 item->ci_dentry = dentry;
208 return error;
209}
210
211int configfs_create_link(struct configfs_symlink *sl,
212 struct dentry *parent,
213 struct dentry *dentry)
214{
215 int err = 0;
216 umode_t mode = S_IFLNK | S_IRWXUGO;
217
Joel Becker3d0f89b2006-01-25 13:31:07 -0800218 err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode,
219 CONFIGFS_ITEM_LINK);
Joel Becker7063fbf2005-12-15 14:29:43 -0800220 if (!err) {
Joel Becker3d0f89b2006-01-25 13:31:07 -0800221 err = configfs_create(dentry, mode, init_symlink);
Joel Becker7063fbf2005-12-15 14:29:43 -0800222 if (!err)
223 dentry->d_op = &configfs_dentry_ops;
Joel Becker3d0f89b2006-01-25 13:31:07 -0800224 else {
225 struct configfs_dirent *sd = dentry->d_fsdata;
226 if (sd) {
227 list_del_init(&sd->s_sibling);
228 configfs_put(sd);
229 }
230 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800231 }
232 return err;
233}
234
235static void remove_dir(struct dentry * d)
236{
237 struct dentry * parent = dget(d->d_parent);
238 struct configfs_dirent * sd;
239
240 sd = d->d_fsdata;
Joel Beckere7515d02006-03-10 11:42:30 -0800241 list_del_init(&sd->s_sibling);
Joel Becker7063fbf2005-12-15 14:29:43 -0800242 configfs_put(sd);
243 if (d->d_inode)
244 simple_rmdir(parent->d_inode,d);
245
246 pr_debug(" o %s removing done (%d)\n",d->d_name.name,
247 atomic_read(&d->d_count));
248
249 dput(parent);
250}
251
252/**
253 * configfs_remove_dir - remove an config_item's directory.
254 * @item: config_item we're removing.
255 *
256 * The only thing special about this is that we remove any files in
257 * the directory before we remove the directory, and we've inlined
258 * what used to be configfs_rmdir() below, instead of calling separately.
259 */
260
261static void configfs_remove_dir(struct config_item * item)
262{
263 struct dentry * dentry = dget(item->ci_dentry);
264
265 if (!dentry)
266 return;
267
268 remove_dir(dentry);
269 /**
270 * Drop reference from dget() on entrance.
271 */
272 dput(dentry);
273}
274
275
276/* attaches attribute's configfs_dirent to the dentry corresponding to the
277 * attribute file
278 */
279static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry)
280{
281 struct configfs_attribute * attr = sd->s_element;
282 int error;
283
Joel Becker7063fbf2005-12-15 14:29:43 -0800284 dentry->d_fsdata = configfs_get(sd);
285 sd->s_dentry = dentry;
Dave Hansence8d2cd2007-10-16 23:31:13 -0700286 error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG,
287 configfs_init_file);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800288 if (error) {
289 configfs_put(sd);
290 return error;
291 }
292
293 dentry->d_op = &configfs_dentry_ops;
Joel Becker7063fbf2005-12-15 14:29:43 -0800294 d_rehash(dentry);
295
296 return 0;
297}
298
299static struct dentry * configfs_lookup(struct inode *dir,
300 struct dentry *dentry,
301 struct nameidata *nd)
302{
303 struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
304 struct configfs_dirent * sd;
305 int found = 0;
306 int err = 0;
307
308 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
309 if (sd->s_type & CONFIGFS_NOT_PINNED) {
310 const unsigned char * name = configfs_get_name(sd);
311
312 if (strcmp(name, dentry->d_name.name))
313 continue;
314
315 found = 1;
316 err = configfs_attach_attr(sd, dentry);
317 break;
318 }
319 }
320
321 if (!found) {
322 /*
323 * If it doesn't exist and it isn't a NOT_PINNED item,
324 * it must be negative.
325 */
326 return simple_lookup(dir, dentry, nd);
327 }
328
329 return ERR_PTR(err);
330}
331
332/*
333 * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800334 * attributes and are removed by rmdir(). We recurse, taking i_mutex
Joel Becker7063fbf2005-12-15 14:29:43 -0800335 * on all children that are candidates for default detach. If the
336 * result is clean, then configfs_detach_group() will handle dropping
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800337 * i_mutex. If there is an error, the caller will clean up the i_mutex
Joel Becker7063fbf2005-12-15 14:29:43 -0800338 * holders via configfs_detach_rollback().
339 */
340static int configfs_detach_prep(struct dentry *dentry)
341{
342 struct configfs_dirent *parent_sd = dentry->d_fsdata;
343 struct configfs_dirent *sd;
344 int ret;
345
346 ret = -EBUSY;
347 if (!list_empty(&parent_sd->s_links))
348 goto out;
349
350 ret = 0;
351 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
352 if (sd->s_type & CONFIGFS_NOT_PINNED)
353 continue;
354 if (sd->s_type & CONFIGFS_USET_DEFAULT) {
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800355 mutex_lock(&sd->s_dentry->d_inode->i_mutex);
356 /* Mark that we've taken i_mutex */
Joel Becker7063fbf2005-12-15 14:29:43 -0800357 sd->s_type |= CONFIGFS_USET_DROPPING;
358
Joel Becker631d1fe2007-06-18 18:06:09 -0700359 /*
360 * Yup, recursive. If there's a problem, blame
361 * deep nesting of default_groups
362 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800363 ret = configfs_detach_prep(sd->s_dentry);
364 if (!ret)
Joel Beckere7515d02006-03-10 11:42:30 -0800365 continue;
Joel Becker7063fbf2005-12-15 14:29:43 -0800366 } else
367 ret = -ENOTEMPTY;
368
369 break;
370 }
371
372out:
373 return ret;
374}
375
376/*
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800377 * Walk the tree, dropping i_mutex wherever CONFIGFS_USET_DROPPING is
Joel Becker7063fbf2005-12-15 14:29:43 -0800378 * set.
379 */
380static void configfs_detach_rollback(struct dentry *dentry)
381{
382 struct configfs_dirent *parent_sd = dentry->d_fsdata;
383 struct configfs_dirent *sd;
384
385 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
386 if (sd->s_type & CONFIGFS_USET_DEFAULT) {
387 configfs_detach_rollback(sd->s_dentry);
388
389 if (sd->s_type & CONFIGFS_USET_DROPPING) {
390 sd->s_type &= ~CONFIGFS_USET_DROPPING;
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800391 mutex_unlock(&sd->s_dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -0800392 }
393 }
394 }
395}
396
397static void detach_attrs(struct config_item * item)
398{
399 struct dentry * dentry = dget(item->ci_dentry);
400 struct configfs_dirent * parent_sd;
401 struct configfs_dirent * sd, * tmp;
402
403 if (!dentry)
404 return;
405
406 pr_debug("configfs %s: dropping attrs for dir\n",
407 dentry->d_name.name);
408
409 parent_sd = dentry->d_fsdata;
410 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
411 if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED))
412 continue;
413 list_del_init(&sd->s_sibling);
414 configfs_drop_dentry(sd, dentry);
415 configfs_put(sd);
416 }
417
418 /**
419 * Drop reference from dget() on entrance.
420 */
421 dput(dentry);
422}
423
424static int populate_attrs(struct config_item *item)
425{
426 struct config_item_type *t = item->ci_type;
427 struct configfs_attribute *attr;
428 int error = 0;
429 int i;
430
431 if (!t)
432 return -EINVAL;
433 if (t->ct_attrs) {
434 for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) {
435 if ((error = configfs_create_file(item, attr)))
436 break;
437 }
438 }
439
440 if (error)
441 detach_attrs(item);
442
443 return error;
444}
445
446static int configfs_attach_group(struct config_item *parent_item,
447 struct config_item *item,
448 struct dentry *dentry);
449static void configfs_detach_group(struct config_item *item);
450
451static void detach_groups(struct config_group *group)
452{
453 struct dentry * dentry = dget(group->cg_item.ci_dentry);
454 struct dentry *child;
455 struct configfs_dirent *parent_sd;
456 struct configfs_dirent *sd, *tmp;
457
458 if (!dentry)
459 return;
460
461 parent_sd = dentry->d_fsdata;
462 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
463 if (!sd->s_element ||
464 !(sd->s_type & CONFIGFS_USET_DEFAULT))
465 continue;
466
467 child = sd->s_dentry;
468
469 configfs_detach_group(sd->s_element);
470 child->d_inode->i_flags |= S_DEAD;
471
472 /*
473 * From rmdir/unregister, a configfs_detach_prep() pass
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800474 * has taken our i_mutex for us. Drop it.
Joel Becker7063fbf2005-12-15 14:29:43 -0800475 * From mkdir/register cleanup, there is no sem held.
476 */
477 if (sd->s_type & CONFIGFS_USET_DROPPING)
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800478 mutex_unlock(&child->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -0800479
480 d_delete(child);
481 dput(child);
482 }
483
484 /**
485 * Drop reference from dget() on entrance.
486 */
487 dput(dentry);
488}
489
490/*
491 * This fakes mkdir(2) on a default_groups[] entry. It
492 * creates a dentry, attachs it, and then does fixup
493 * on the sd->s_type.
494 *
495 * We could, perhaps, tweak our parent's ->mkdir for a minute and
496 * try using vfs_mkdir. Just a thought.
497 */
498static int create_default_group(struct config_group *parent_group,
499 struct config_group *group)
500{
501 int ret;
502 struct qstr name;
503 struct configfs_dirent *sd;
504 /* We trust the caller holds a reference to parent */
505 struct dentry *child, *parent = parent_group->cg_item.ci_dentry;
506
507 if (!group->cg_item.ci_name)
508 group->cg_item.ci_name = group->cg_item.ci_namebuf;
509 name.name = group->cg_item.ci_name;
510 name.len = strlen(name.name);
511 name.hash = full_name_hash(name.name, name.len);
512
513 ret = -ENOMEM;
514 child = d_alloc(parent, &name);
515 if (child) {
516 d_add(child, NULL);
517
518 ret = configfs_attach_group(&parent_group->cg_item,
519 &group->cg_item, child);
520 if (!ret) {
521 sd = child->d_fsdata;
522 sd->s_type |= CONFIGFS_USET_DEFAULT;
523 } else {
524 d_delete(child);
525 dput(child);
526 }
527 }
528
529 return ret;
530}
531
532static int populate_groups(struct config_group *group)
533{
534 struct config_group *new_group;
535 struct dentry *dentry = group->cg_item.ci_dentry;
536 int ret = 0;
537 int i;
538
Eric Sesterhenncbca6922006-03-23 00:36:54 +0100539 if (group->default_groups) {
Joel Beckereed7a0d2006-04-11 21:37:20 -0700540 /*
541 * FYI, we're faking mkdir here
Joel Becker7063fbf2005-12-15 14:29:43 -0800542 * I'm not sure we need this semaphore, as we're called
543 * from our parent's mkdir. That holds our parent's
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800544 * i_mutex, so afaik lookup cannot continue through our
Joel Becker7063fbf2005-12-15 14:29:43 -0800545 * parent to find us, let alone mess with our tree.
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800546 * That said, taking our i_mutex is closer to mkdir
Joel Beckereed7a0d2006-04-11 21:37:20 -0700547 * emulation, and shouldn't hurt.
548 */
Joonwoo Parkba611ed2007-12-26 12:09:57 +0900549 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD);
Joel Becker7063fbf2005-12-15 14:29:43 -0800550
551 for (i = 0; group->default_groups[i]; i++) {
552 new_group = group->default_groups[i];
553
554 ret = create_default_group(group, new_group);
555 if (ret)
556 break;
557 }
558
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800559 mutex_unlock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -0800560 }
561
562 if (ret)
563 detach_groups(group);
564
565 return ret;
566}
567
568/*
569 * All of link_obj/unlink_obj/link_group/unlink_group require that
Joel Beckere6bd07a2007-07-06 23:33:17 -0700570 * subsys->su_mutex is held.
Joel Becker7063fbf2005-12-15 14:29:43 -0800571 */
572
573static void unlink_obj(struct config_item *item)
574{
575 struct config_group *group;
576
577 group = item->ci_group;
578 if (group) {
579 list_del_init(&item->ci_entry);
580
581 item->ci_group = NULL;
582 item->ci_parent = NULL;
Joel Beckereed7a0d2006-04-11 21:37:20 -0700583
584 /* Drop the reference for ci_entry */
Joel Becker7063fbf2005-12-15 14:29:43 -0800585 config_item_put(item);
586
Joel Beckereed7a0d2006-04-11 21:37:20 -0700587 /* Drop the reference for ci_parent */
Joel Becker7063fbf2005-12-15 14:29:43 -0800588 config_group_put(group);
589 }
590}
591
592static void link_obj(struct config_item *parent_item, struct config_item *item)
593{
Joel Beckereed7a0d2006-04-11 21:37:20 -0700594 /*
595 * Parent seems redundant with group, but it makes certain
596 * traversals much nicer.
597 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800598 item->ci_parent = parent_item;
Joel Beckereed7a0d2006-04-11 21:37:20 -0700599
600 /*
601 * We hold a reference on the parent for the child's ci_parent
602 * link.
603 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800604 item->ci_group = config_group_get(to_config_group(parent_item));
605 list_add_tail(&item->ci_entry, &item->ci_group->cg_children);
606
Joel Beckereed7a0d2006-04-11 21:37:20 -0700607 /*
608 * We hold a reference on the child for ci_entry on the parent's
609 * cg_children
610 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800611 config_item_get(item);
612}
613
614static void unlink_group(struct config_group *group)
615{
616 int i;
617 struct config_group *new_group;
618
619 if (group->default_groups) {
620 for (i = 0; group->default_groups[i]; i++) {
621 new_group = group->default_groups[i];
622 unlink_group(new_group);
623 }
624 }
625
626 group->cg_subsys = NULL;
627 unlink_obj(&group->cg_item);
628}
629
630static void link_group(struct config_group *parent_group, struct config_group *group)
631{
632 int i;
633 struct config_group *new_group;
634 struct configfs_subsystem *subsys = NULL; /* gcc is a turd */
635
636 link_obj(&parent_group->cg_item, &group->cg_item);
637
638 if (parent_group->cg_subsys)
639 subsys = parent_group->cg_subsys;
640 else if (configfs_is_root(&parent_group->cg_item))
641 subsys = to_configfs_subsystem(group);
642 else
643 BUG();
644 group->cg_subsys = subsys;
645
646 if (group->default_groups) {
647 for (i = 0; group->default_groups[i]; i++) {
648 new_group = group->default_groups[i];
649 link_group(group, new_group);
650 }
651 }
652}
653
654/*
655 * The goal is that configfs_attach_item() (and
656 * configfs_attach_group()) can be called from either the VFS or this
657 * module. That is, they assume that the items have been created,
658 * the dentry allocated, and the dcache is all ready to go.
659 *
660 * If they fail, they must clean up after themselves as if they
661 * had never been called. The caller (VFS or local function) will
662 * handle cleaning up the dcache bits.
663 *
664 * configfs_detach_group() and configfs_detach_item() behave similarly on
665 * the way out. They assume that the proper semaphores are held, they
666 * clean up the configfs items, and they expect their callers will
667 * handle the dcache bits.
668 */
669static int configfs_attach_item(struct config_item *parent_item,
670 struct config_item *item,
671 struct dentry *dentry)
672{
673 int ret;
674
675 ret = configfs_create_dir(item, dentry);
676 if (!ret) {
677 ret = populate_attrs(item);
678 if (ret) {
679 configfs_remove_dir(item);
680 d_delete(dentry);
681 }
682 }
683
684 return ret;
685}
686
687static void configfs_detach_item(struct config_item *item)
688{
689 detach_attrs(item);
690 configfs_remove_dir(item);
691}
692
693static int configfs_attach_group(struct config_item *parent_item,
694 struct config_item *item,
695 struct dentry *dentry)
696{
697 int ret;
698 struct configfs_dirent *sd;
699
700 ret = configfs_attach_item(parent_item, item, dentry);
701 if (!ret) {
702 sd = dentry->d_fsdata;
703 sd->s_type |= CONFIGFS_USET_DIR;
704
705 ret = populate_groups(to_config_group(item));
706 if (ret) {
707 configfs_detach_item(item);
708 d_delete(dentry);
709 }
710 }
711
712 return ret;
713}
714
715static void configfs_detach_group(struct config_item *item)
716{
717 detach_groups(to_config_group(item));
718 configfs_detach_item(item);
719}
720
721/*
Joel Becker299894c2006-10-06 17:33:23 -0700722 * After the item has been detached from the filesystem view, we are
723 * ready to tear it out of the hierarchy. Notify the client before
724 * we do that so they can perform any cleanup that requires
725 * navigating the hierarchy. A client does not need to provide this
726 * callback. The subsystem semaphore MUST be held by the caller, and
727 * references must be valid for both items. It also assumes the
728 * caller has validated ci_type.
729 */
730static void client_disconnect_notify(struct config_item *parent_item,
731 struct config_item *item)
732{
733 struct config_item_type *type;
734
735 type = parent_item->ci_type;
736 BUG_ON(!type);
737
738 if (type->ct_group_ops && type->ct_group_ops->disconnect_notify)
739 type->ct_group_ops->disconnect_notify(to_config_group(parent_item),
740 item);
741}
742
743/*
Joel Becker7063fbf2005-12-15 14:29:43 -0800744 * Drop the initial reference from make_item()/make_group()
745 * This function assumes that reference is held on item
746 * and that item holds a valid reference to the parent. Also, it
747 * assumes the caller has validated ci_type.
748 */
749static void client_drop_item(struct config_item *parent_item,
750 struct config_item *item)
751{
752 struct config_item_type *type;
753
754 type = parent_item->ci_type;
755 BUG_ON(!type);
756
Joel Beckereed7a0d2006-04-11 21:37:20 -0700757 /*
758 * If ->drop_item() exists, it is responsible for the
759 * config_item_put().
760 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800761 if (type->ct_group_ops && type->ct_group_ops->drop_item)
762 type->ct_group_ops->drop_item(to_config_group(parent_item),
Joel Becker299894c2006-10-06 17:33:23 -0700763 item);
Joel Becker7063fbf2005-12-15 14:29:43 -0800764 else
765 config_item_put(item);
766}
767
Joel Becker631d1fe2007-06-18 18:06:09 -0700768#ifdef DEBUG
769static void configfs_dump_one(struct configfs_dirent *sd, int level)
770{
771 printk(KERN_INFO "%*s\"%s\":\n", level, " ", configfs_get_name(sd));
772
773#define type_print(_type) if (sd->s_type & _type) printk(KERN_INFO "%*s %s\n", level, " ", #_type);
774 type_print(CONFIGFS_ROOT);
775 type_print(CONFIGFS_DIR);
776 type_print(CONFIGFS_ITEM_ATTR);
777 type_print(CONFIGFS_ITEM_LINK);
778 type_print(CONFIGFS_USET_DIR);
779 type_print(CONFIGFS_USET_DEFAULT);
780 type_print(CONFIGFS_USET_DROPPING);
781#undef type_print
782}
783
784static int configfs_dump(struct configfs_dirent *sd, int level)
785{
786 struct configfs_dirent *child_sd;
787 int ret = 0;
788
789 configfs_dump_one(sd, level);
790
791 if (!(sd->s_type & (CONFIGFS_DIR|CONFIGFS_ROOT)))
792 return 0;
793
794 list_for_each_entry(child_sd, &sd->s_children, s_sibling) {
795 ret = configfs_dump(child_sd, level + 2);
796 if (ret)
797 break;
798 }
799
800 return ret;
801}
802#endif
803
804
805/*
806 * configfs_depend_item() and configfs_undepend_item()
807 *
808 * WARNING: Do not call these from a configfs callback!
809 *
810 * This describes these functions and their helpers.
811 *
812 * Allow another kernel system to depend on a config_item. If this
813 * happens, the item cannot go away until the dependant can live without
814 * it. The idea is to give client modules as simple an interface as
815 * possible. When a system asks them to depend on an item, they just
816 * call configfs_depend_item(). If the item is live and the client
817 * driver is in good shape, we'll happily do the work for them.
818 *
819 * Why is the locking complex? Because configfs uses the VFS to handle
820 * all locking, but this function is called outside the normal
821 * VFS->configfs path. So it must take VFS locks to prevent the
822 * VFS->configfs stuff (configfs_mkdir(), configfs_rmdir(), etc). This is
823 * why you can't call these functions underneath configfs callbacks.
824 *
825 * Note, btw, that this can be called at *any* time, even when a configfs
826 * subsystem isn't registered, or when configfs is loading or unloading.
827 * Just like configfs_register_subsystem(). So we take the same
828 * precautions. We pin the filesystem. We lock each i_mutex _in_order_
829 * on our way down the tree. If we can find the target item in the
830 * configfs tree, it must be part of the subsystem tree as well, so we
831 * do not need the subsystem semaphore. Holding the i_mutex chain locks
832 * out mkdir() and rmdir(), who might be racing us.
833 */
834
835/*
836 * configfs_depend_prep()
837 *
838 * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are
839 * attributes. This is similar but not the same to configfs_detach_prep().
840 * Note that configfs_detach_prep() expects the parent to be locked when it
841 * is called, but we lock the parent *inside* configfs_depend_prep(). We
842 * do that so we can unlock it if we find nothing.
843 *
844 * Here we do a depth-first search of the dentry hierarchy looking for
845 * our object. We take i_mutex on each step of the way down. IT IS
846 * ESSENTIAL THAT i_mutex LOCKING IS ORDERED. If we come back up a branch,
847 * we'll drop the i_mutex.
848 *
849 * If the target is not found, -ENOENT is bubbled up and we have released
850 * all locks. If the target was found, the locks will be cleared by
851 * configfs_depend_rollback().
852 *
853 * This adds a requirement that all config_items be unique!
854 *
855 * This is recursive because the locking traversal is tricky. There isn't
856 * much on the stack, though, so folks that need this function - be careful
857 * about your stack! Patches will be accepted to make it iterative.
858 */
859static int configfs_depend_prep(struct dentry *origin,
860 struct config_item *target)
861{
862 struct configfs_dirent *child_sd, *sd = origin->d_fsdata;
863 int ret = 0;
864
865 BUG_ON(!origin || !sd);
866
867 /* Lock this guy on the way down */
868 mutex_lock(&sd->s_dentry->d_inode->i_mutex);
869 if (sd->s_element == target) /* Boo-yah */
870 goto out;
871
872 list_for_each_entry(child_sd, &sd->s_children, s_sibling) {
873 if (child_sd->s_type & CONFIGFS_DIR) {
874 ret = configfs_depend_prep(child_sd->s_dentry,
875 target);
876 if (!ret)
877 goto out; /* Child path boo-yah */
878 }
879 }
880
881 /* We looped all our children and didn't find target */
882 mutex_unlock(&sd->s_dentry->d_inode->i_mutex);
883 ret = -ENOENT;
884
885out:
886 return ret;
887}
888
889/*
890 * This is ONLY called if configfs_depend_prep() did its job. So we can
891 * trust the entire path from item back up to origin.
892 *
893 * We walk backwards from item, unlocking each i_mutex. We finish by
894 * unlocking origin.
895 */
896static void configfs_depend_rollback(struct dentry *origin,
897 struct config_item *item)
898{
899 struct dentry *dentry = item->ci_dentry;
900
901 while (dentry != origin) {
902 mutex_unlock(&dentry->d_inode->i_mutex);
903 dentry = dentry->d_parent;
904 }
905
906 mutex_unlock(&origin->d_inode->i_mutex);
907}
908
909int configfs_depend_item(struct configfs_subsystem *subsys,
910 struct config_item *target)
911{
912 int ret;
913 struct configfs_dirent *p, *root_sd, *subsys_sd = NULL;
914 struct config_item *s_item = &subsys->su_group.cg_item;
915
916 /*
917 * Pin the configfs filesystem. This means we can safely access
918 * the root of the configfs filesystem.
919 */
920 ret = configfs_pin_fs();
921 if (ret)
922 return ret;
923
924 /*
925 * Next, lock the root directory. We're going to check that the
926 * subsystem is really registered, and so we need to lock out
927 * configfs_[un]register_subsystem().
928 */
929 mutex_lock(&configfs_sb->s_root->d_inode->i_mutex);
930
931 root_sd = configfs_sb->s_root->d_fsdata;
932
933 list_for_each_entry(p, &root_sd->s_children, s_sibling) {
934 if (p->s_type & CONFIGFS_DIR) {
935 if (p->s_element == s_item) {
936 subsys_sd = p;
937 break;
938 }
939 }
940 }
941
942 if (!subsys_sd) {
943 ret = -ENOENT;
944 goto out_unlock_fs;
945 }
946
947 /* Ok, now we can trust subsys/s_item */
948
949 /* Scan the tree, locking i_mutex recursively, return 0 if found */
950 ret = configfs_depend_prep(subsys_sd->s_dentry, target);
951 if (ret)
952 goto out_unlock_fs;
953
954 /* We hold all i_mutexes from the subsystem down to the target */
955 p = target->ci_dentry->d_fsdata;
956 p->s_dependent_count += 1;
957
958 configfs_depend_rollback(subsys_sd->s_dentry, target);
959
960out_unlock_fs:
961 mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
962
963 /*
964 * If we succeeded, the fs is pinned via other methods. If not,
965 * we're done with it anyway. So release_fs() is always right.
966 */
967 configfs_release_fs();
968
969 return ret;
970}
971EXPORT_SYMBOL(configfs_depend_item);
972
973/*
974 * Release the dependent linkage. This is much simpler than
975 * configfs_depend_item() because we know that that the client driver is
976 * pinned, thus the subsystem is pinned, and therefore configfs is pinned.
977 */
978void configfs_undepend_item(struct configfs_subsystem *subsys,
979 struct config_item *target)
980{
981 struct configfs_dirent *sd;
982
983 /*
984 * Since we can trust everything is pinned, we just need i_mutex
985 * on the item.
986 */
987 mutex_lock(&target->ci_dentry->d_inode->i_mutex);
988
989 sd = target->ci_dentry->d_fsdata;
990 BUG_ON(sd->s_dependent_count < 1);
991
992 sd->s_dependent_count -= 1;
993
994 /*
995 * After this unlock, we cannot trust the item to stay alive!
996 * DO NOT REFERENCE item after this unlock.
997 */
998 mutex_unlock(&target->ci_dentry->d_inode->i_mutex);
999}
1000EXPORT_SYMBOL(configfs_undepend_item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001001
1002static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
1003{
Joel Beckereed7a0d2006-04-11 21:37:20 -07001004 int ret, module_got = 0;
Joel Becker7063fbf2005-12-15 14:29:43 -08001005 struct config_group *group;
1006 struct config_item *item;
1007 struct config_item *parent_item;
1008 struct configfs_subsystem *subsys;
1009 struct configfs_dirent *sd;
1010 struct config_item_type *type;
Joel Beckereed7a0d2006-04-11 21:37:20 -07001011 struct module *owner = NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -08001012 char *name;
1013
Joel Becker84efad12006-03-27 18:46:09 -08001014 if (dentry->d_parent == configfs_sb->s_root) {
1015 ret = -EPERM;
1016 goto out;
1017 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001018
1019 sd = dentry->d_parent->d_fsdata;
Joel Becker84efad12006-03-27 18:46:09 -08001020 if (!(sd->s_type & CONFIGFS_USET_DIR)) {
1021 ret = -EPERM;
1022 goto out;
1023 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001024
Joel Becker84efad12006-03-27 18:46:09 -08001025 /* Get a working ref for the duration of this function */
Joel Becker7063fbf2005-12-15 14:29:43 -08001026 parent_item = configfs_get_config_item(dentry->d_parent);
1027 type = parent_item->ci_type;
1028 subsys = to_config_group(parent_item)->cg_subsys;
1029 BUG_ON(!subsys);
1030
1031 if (!type || !type->ct_group_ops ||
1032 (!type->ct_group_ops->make_group &&
1033 !type->ct_group_ops->make_item)) {
Joel Becker84efad12006-03-27 18:46:09 -08001034 ret = -EPERM; /* Lack-of-mkdir returns -EPERM */
1035 goto out_put;
Joel Becker7063fbf2005-12-15 14:29:43 -08001036 }
1037
1038 name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL);
1039 if (!name) {
Joel Becker84efad12006-03-27 18:46:09 -08001040 ret = -ENOMEM;
1041 goto out_put;
Joel Becker7063fbf2005-12-15 14:29:43 -08001042 }
Joel Becker84efad12006-03-27 18:46:09 -08001043
Joel Becker7063fbf2005-12-15 14:29:43 -08001044 snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name);
1045
Joel Beckere6bd07a2007-07-06 23:33:17 -07001046 mutex_lock(&subsys->su_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001047 group = NULL;
1048 item = NULL;
1049 if (type->ct_group_ops->make_group) {
1050 group = type->ct_group_ops->make_group(to_config_group(parent_item), name);
1051 if (group) {
1052 link_group(to_config_group(parent_item), group);
1053 item = &group->cg_item;
1054 }
1055 } else {
1056 item = type->ct_group_ops->make_item(to_config_group(parent_item), name);
1057 if (item)
1058 link_obj(parent_item, item);
1059 }
Joel Beckere6bd07a2007-07-06 23:33:17 -07001060 mutex_unlock(&subsys->su_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001061
1062 kfree(name);
1063 if (!item) {
Joel Beckereed7a0d2006-04-11 21:37:20 -07001064 /*
1065 * If item == NULL, then link_obj() was never called.
1066 * There are no extra references to clean up.
1067 */
Joel Becker84efad12006-03-27 18:46:09 -08001068 ret = -ENOMEM;
1069 goto out_put;
Joel Becker7063fbf2005-12-15 14:29:43 -08001070 }
1071
Joel Beckereed7a0d2006-04-11 21:37:20 -07001072 /*
1073 * link_obj() has been called (via link_group() for groups).
1074 * From here on out, errors must clean that up.
1075 */
1076
Joel Becker7063fbf2005-12-15 14:29:43 -08001077 type = item->ci_type;
Joel Beckereed7a0d2006-04-11 21:37:20 -07001078 if (!type) {
1079 ret = -EINVAL;
1080 goto out_unlink;
1081 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001082
Joel Beckereed7a0d2006-04-11 21:37:20 -07001083 owner = type->ct_owner;
1084 if (!try_module_get(owner)) {
1085 ret = -EINVAL;
1086 goto out_unlink;
1087 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001088
Joel Beckereed7a0d2006-04-11 21:37:20 -07001089 /*
1090 * I hate doing it this way, but if there is
1091 * an error, module_put() probably should
1092 * happen after any cleanup.
1093 */
1094 module_got = 1;
1095
1096 if (group)
1097 ret = configfs_attach_group(parent_item, item, dentry);
1098 else
1099 ret = configfs_attach_item(parent_item, item, dentry);
1100
1101out_unlink:
1102 if (ret) {
1103 /* Tear down everything we built up */
Joel Beckere6bd07a2007-07-06 23:33:17 -07001104 mutex_lock(&subsys->su_mutex);
Joel Becker299894c2006-10-06 17:33:23 -07001105
1106 client_disconnect_notify(parent_item, item);
Joel Beckereed7a0d2006-04-11 21:37:20 -07001107 if (group)
1108 unlink_group(group);
1109 else
1110 unlink_obj(item);
1111 client_drop_item(parent_item, item);
Joel Becker299894c2006-10-06 17:33:23 -07001112
Joel Beckere6bd07a2007-07-06 23:33:17 -07001113 mutex_unlock(&subsys->su_mutex);
Joel Beckereed7a0d2006-04-11 21:37:20 -07001114
1115 if (module_got)
1116 module_put(owner);
Joel Becker7063fbf2005-12-15 14:29:43 -08001117 }
1118
Joel Becker84efad12006-03-27 18:46:09 -08001119out_put:
1120 /*
Joel Beckereed7a0d2006-04-11 21:37:20 -07001121 * link_obj()/link_group() took a reference from child->parent,
1122 * so the parent is safely pinned. We can drop our working
1123 * reference.
Joel Becker84efad12006-03-27 18:46:09 -08001124 */
1125 config_item_put(parent_item);
1126
1127out:
Joel Becker7063fbf2005-12-15 14:29:43 -08001128 return ret;
1129}
1130
1131static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
1132{
1133 struct config_item *parent_item;
1134 struct config_item *item;
1135 struct configfs_subsystem *subsys;
1136 struct configfs_dirent *sd;
1137 struct module *owner = NULL;
1138 int ret;
1139
1140 if (dentry->d_parent == configfs_sb->s_root)
1141 return -EPERM;
1142
1143 sd = dentry->d_fsdata;
1144 if (sd->s_type & CONFIGFS_USET_DEFAULT)
1145 return -EPERM;
1146
Joel Becker631d1fe2007-06-18 18:06:09 -07001147 /*
1148 * Here's where we check for dependents. We're protected by
1149 * i_mutex.
1150 */
1151 if (sd->s_dependent_count)
1152 return -EBUSY;
1153
Joel Becker84efad12006-03-27 18:46:09 -08001154 /* Get a working ref until we have the child */
Joel Becker7063fbf2005-12-15 14:29:43 -08001155 parent_item = configfs_get_config_item(dentry->d_parent);
1156 subsys = to_config_group(parent_item)->cg_subsys;
1157 BUG_ON(!subsys);
1158
1159 if (!parent_item->ci_type) {
1160 config_item_put(parent_item);
1161 return -EINVAL;
1162 }
1163
1164 ret = configfs_detach_prep(dentry);
1165 if (ret) {
1166 configfs_detach_rollback(dentry);
1167 config_item_put(parent_item);
1168 return ret;
1169 }
1170
Joel Becker84efad12006-03-27 18:46:09 -08001171 /* Get a working ref for the duration of this function */
Joel Becker7063fbf2005-12-15 14:29:43 -08001172 item = configfs_get_config_item(dentry);
1173
1174 /* Drop reference from above, item already holds one. */
1175 config_item_put(parent_item);
1176
1177 if (item->ci_type)
1178 owner = item->ci_type->ct_owner;
1179
1180 if (sd->s_type & CONFIGFS_USET_DIR) {
1181 configfs_detach_group(item);
1182
Joel Beckere6bd07a2007-07-06 23:33:17 -07001183 mutex_lock(&subsys->su_mutex);
Joel Becker299894c2006-10-06 17:33:23 -07001184 client_disconnect_notify(parent_item, item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001185 unlink_group(to_config_group(item));
1186 } else {
1187 configfs_detach_item(item);
1188
Joel Beckere6bd07a2007-07-06 23:33:17 -07001189 mutex_lock(&subsys->su_mutex);
Joel Becker299894c2006-10-06 17:33:23 -07001190 client_disconnect_notify(parent_item, item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001191 unlink_obj(item);
1192 }
1193
1194 client_drop_item(parent_item, item);
Joel Beckere6bd07a2007-07-06 23:33:17 -07001195 mutex_unlock(&subsys->su_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001196
1197 /* Drop our reference from above */
1198 config_item_put(item);
1199
1200 module_put(owner);
1201
1202 return 0;
1203}
1204
Arjan van de Ven754661f2007-02-12 00:55:38 -08001205const struct inode_operations configfs_dir_inode_operations = {
Joel Becker7063fbf2005-12-15 14:29:43 -08001206 .mkdir = configfs_mkdir,
1207 .rmdir = configfs_rmdir,
1208 .symlink = configfs_symlink,
1209 .unlink = configfs_unlink,
1210 .lookup = configfs_lookup,
Joel Becker3d0f89b2006-01-25 13:31:07 -08001211 .setattr = configfs_setattr,
Joel Becker7063fbf2005-12-15 14:29:43 -08001212};
1213
1214#if 0
1215int configfs_rename_dir(struct config_item * item, const char *new_name)
1216{
1217 int error = 0;
1218 struct dentry * new_dentry, * parent;
1219
1220 if (!strcmp(config_item_name(item), new_name))
1221 return -EINVAL;
1222
1223 if (!item->parent)
1224 return -EINVAL;
1225
1226 down_write(&configfs_rename_sem);
1227 parent = item->parent->dentry;
1228
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001229 mutex_lock(&parent->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001230
1231 new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
1232 if (!IS_ERR(new_dentry)) {
Joel Beckere7515d02006-03-10 11:42:30 -08001233 if (!new_dentry->d_inode) {
Joel Becker7063fbf2005-12-15 14:29:43 -08001234 error = config_item_set_name(item, "%s", new_name);
1235 if (!error) {
1236 d_add(new_dentry, NULL);
1237 d_move(item->dentry, new_dentry);
1238 }
1239 else
1240 d_delete(new_dentry);
1241 } else
1242 error = -EEXIST;
1243 dput(new_dentry);
1244 }
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001245 mutex_unlock(&parent->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001246 up_write(&configfs_rename_sem);
1247
1248 return error;
1249}
1250#endif
1251
1252static int configfs_dir_open(struct inode *inode, struct file *file)
1253{
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001254 struct dentry * dentry = file->f_path.dentry;
Joel Becker7063fbf2005-12-15 14:29:43 -08001255 struct configfs_dirent * parent_sd = dentry->d_fsdata;
1256
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001257 mutex_lock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001258 file->private_data = configfs_new_dirent(parent_sd, NULL);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001259 mutex_unlock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001260
1261 return file->private_data ? 0 : -ENOMEM;
1262
1263}
1264
1265static int configfs_dir_close(struct inode *inode, struct file *file)
1266{
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001267 struct dentry * dentry = file->f_path.dentry;
Joel Becker7063fbf2005-12-15 14:29:43 -08001268 struct configfs_dirent * cursor = file->private_data;
1269
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001270 mutex_lock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001271 list_del_init(&cursor->s_sibling);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001272 mutex_unlock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001273
1274 release_configfs_dirent(cursor);
1275
1276 return 0;
1277}
1278
1279/* Relationship between s_mode and the DT_xxx types */
1280static inline unsigned char dt_type(struct configfs_dirent *sd)
1281{
1282 return (sd->s_mode >> 12) & 15;
1283}
1284
1285static int configfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
1286{
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001287 struct dentry *dentry = filp->f_path.dentry;
Joel Becker7063fbf2005-12-15 14:29:43 -08001288 struct configfs_dirent * parent_sd = dentry->d_fsdata;
1289 struct configfs_dirent *cursor = filp->private_data;
1290 struct list_head *p, *q = &cursor->s_sibling;
1291 ino_t ino;
1292 int i = filp->f_pos;
1293
1294 switch (i) {
1295 case 0:
1296 ino = dentry->d_inode->i_ino;
1297 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
1298 break;
1299 filp->f_pos++;
1300 i++;
1301 /* fallthrough */
1302 case 1:
1303 ino = parent_ino(dentry);
1304 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
1305 break;
1306 filp->f_pos++;
1307 i++;
1308 /* fallthrough */
1309 default:
1310 if (filp->f_pos == 2) {
Akinobu Mitaf1166292006-06-26 00:24:46 -07001311 list_move(q, &parent_sd->s_children);
Joel Becker7063fbf2005-12-15 14:29:43 -08001312 }
1313 for (p=q->next; p!= &parent_sd->s_children; p=p->next) {
1314 struct configfs_dirent *next;
1315 const char * name;
1316 int len;
1317
1318 next = list_entry(p, struct configfs_dirent,
1319 s_sibling);
1320 if (!next->s_element)
1321 continue;
1322
1323 name = configfs_get_name(next);
1324 len = strlen(name);
1325 if (next->s_dentry)
1326 ino = next->s_dentry->d_inode->i_ino;
1327 else
1328 ino = iunique(configfs_sb, 2);
1329
1330 if (filldir(dirent, name, len, filp->f_pos, ino,
1331 dt_type(next)) < 0)
1332 return 0;
1333
Akinobu Mitaf1166292006-06-26 00:24:46 -07001334 list_move(q, p);
Joel Becker7063fbf2005-12-15 14:29:43 -08001335 p = q;
1336 filp->f_pos++;
1337 }
1338 }
1339 return 0;
1340}
1341
1342static loff_t configfs_dir_lseek(struct file * file, loff_t offset, int origin)
1343{
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001344 struct dentry * dentry = file->f_path.dentry;
Joel Becker7063fbf2005-12-15 14:29:43 -08001345
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001346 mutex_lock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001347 switch (origin) {
1348 case 1:
1349 offset += file->f_pos;
1350 case 0:
1351 if (offset >= 0)
1352 break;
1353 default:
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001354 mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001355 return -EINVAL;
1356 }
1357 if (offset != file->f_pos) {
1358 file->f_pos = offset;
1359 if (file->f_pos >= 2) {
1360 struct configfs_dirent *sd = dentry->d_fsdata;
1361 struct configfs_dirent *cursor = file->private_data;
1362 struct list_head *p;
1363 loff_t n = file->f_pos - 2;
1364
1365 list_del(&cursor->s_sibling);
1366 p = sd->s_children.next;
1367 while (n && p != &sd->s_children) {
1368 struct configfs_dirent *next;
1369 next = list_entry(p, struct configfs_dirent,
1370 s_sibling);
1371 if (next->s_element)
1372 n--;
1373 p = p->next;
1374 }
1375 list_add_tail(&cursor->s_sibling, p);
1376 }
1377 }
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001378 mutex_unlock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001379 return offset;
1380}
1381
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -08001382const struct file_operations configfs_dir_operations = {
Joel Becker7063fbf2005-12-15 14:29:43 -08001383 .open = configfs_dir_open,
1384 .release = configfs_dir_close,
1385 .llseek = configfs_dir_lseek,
1386 .read = generic_read_dir,
1387 .readdir = configfs_readdir,
1388};
1389
1390int configfs_register_subsystem(struct configfs_subsystem *subsys)
1391{
1392 int err;
1393 struct config_group *group = &subsys->su_group;
1394 struct qstr name;
1395 struct dentry *dentry;
1396 struct configfs_dirent *sd;
1397
1398 err = configfs_pin_fs();
1399 if (err)
1400 return err;
1401
1402 if (!group->cg_item.ci_name)
1403 group->cg_item.ci_name = group->cg_item.ci_namebuf;
1404
1405 sd = configfs_sb->s_root->d_fsdata;
1406 link_group(to_config_group(sd->s_element), group);
1407
Joonwoo Parkba611ed2007-12-26 12:09:57 +09001408 mutex_lock_nested(&configfs_sb->s_root->d_inode->i_mutex,
1409 I_MUTEX_PARENT);
Joel Becker7063fbf2005-12-15 14:29:43 -08001410
1411 name.name = group->cg_item.ci_name;
1412 name.len = strlen(name.name);
1413 name.hash = full_name_hash(name.name, name.len);
1414
1415 err = -ENOMEM;
1416 dentry = d_alloc(configfs_sb->s_root, &name);
Joel Beckerafdf04e2007-03-05 15:49:49 -08001417 if (dentry) {
1418 d_add(dentry, NULL);
Joel Becker7063fbf2005-12-15 14:29:43 -08001419
Joel Beckerafdf04e2007-03-05 15:49:49 -08001420 err = configfs_attach_group(sd->s_element, &group->cg_item,
1421 dentry);
1422 if (err) {
1423 d_delete(dentry);
1424 dput(dentry);
1425 }
1426 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001427
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001428 mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001429
Joel Beckerafdf04e2007-03-05 15:49:49 -08001430 if (err) {
1431 unlink_group(group);
1432 configfs_release_fs();
Joel Becker7063fbf2005-12-15 14:29:43 -08001433 }
1434
1435 return err;
1436}
1437
1438void configfs_unregister_subsystem(struct configfs_subsystem *subsys)
1439{
1440 struct config_group *group = &subsys->su_group;
1441 struct dentry *dentry = group->cg_item.ci_dentry;
1442
1443 if (dentry->d_parent != configfs_sb->s_root) {
1444 printk(KERN_ERR "configfs: Tried to unregister non-subsystem!\n");
1445 return;
1446 }
1447
Mark Fasheh55ed1602006-10-20 14:55:54 -07001448 mutex_lock_nested(&configfs_sb->s_root->d_inode->i_mutex,
1449 I_MUTEX_PARENT);
1450 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD);
Joel Becker7063fbf2005-12-15 14:29:43 -08001451 if (configfs_detach_prep(dentry)) {
1452 printk(KERN_ERR "configfs: Tried to unregister non-empty subsystem!\n");
1453 }
1454 configfs_detach_group(&group->cg_item);
1455 dentry->d_inode->i_flags |= S_DEAD;
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001456 mutex_unlock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001457
1458 d_delete(dentry);
1459
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001460 mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001461
1462 dput(dentry);
1463
1464 unlink_group(group);
1465 configfs_release_fs();
1466}
1467
1468EXPORT_SYMBOL(configfs_register_subsystem);
1469EXPORT_SYMBOL(configfs_unregister_subsystem);