blob: 8e48b52205aac439106638c82546ff351f0ed955 [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>
Louis Rilling107ed402008-06-16 19:01:00 +020033#include <linux/err.h>
Joel Becker7063fbf2005-12-15 14:29:43 -080034
35#include <linux/configfs.h>
36#include "configfs_internal.h"
37
38DECLARE_RWSEM(configfs_rename_sem);
Louis Rilling6f610762008-06-16 19:00:58 +020039/*
40 * Protects mutations of configfs_dirent linkage together with proper i_mutex
Louis Rilling5301a772008-06-16 19:00:59 +020041 * Also protects mutations of symlinks linkage to target configfs_dirent
Louis Rilling6f610762008-06-16 19:00:58 +020042 * Mutators of configfs_dirent linkage must *both* have the proper inode locked
43 * and configfs_dirent_lock locked, in that order.
Louis Rilling5301a772008-06-16 19:00:59 +020044 * This allows one to safely traverse configfs_dirent trees and symlinks without
45 * having to lock inodes.
Louis Rillingb3e76af2008-06-16 19:01:01 +020046 *
47 * Protects setting of CONFIGFS_USET_DROPPING: checking the flag
48 * unlocked is not reliable unless in detach_groups() called from
49 * rmdir()/unregister() and from configfs_attach_group()
Louis Rilling6f610762008-06-16 19:00:58 +020050 */
51DEFINE_SPINLOCK(configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -080052
53static void configfs_d_iput(struct dentry * dentry,
54 struct inode * inode)
55{
56 struct configfs_dirent * sd = dentry->d_fsdata;
57
58 if (sd) {
59 BUG_ON(sd->s_dentry != dentry);
60 sd->s_dentry = NULL;
61 configfs_put(sd);
62 }
63 iput(inode);
64}
65
66/*
67 * We _must_ delete our dentries on last dput, as the chain-to-parent
68 * behavior is required to clear the parents of default_groups.
69 */
70static int configfs_d_delete(struct dentry *dentry)
71{
72 return 1;
73}
74
Al Viro296c2d82009-02-20 06:02:01 +000075static const struct dentry_operations configfs_dentry_ops = {
Joel Becker7063fbf2005-12-15 14:29:43 -080076 .d_iput = configfs_d_iput,
77 /* simple_delete_dentry() isn't exported */
78 .d_delete = configfs_d_delete,
79};
80
Louis Rillinge74cc062009-01-28 19:18:32 +010081#ifdef CONFIG_LOCKDEP
82
83/*
84 * Helpers to make lockdep happy with our recursive locking of default groups'
85 * inodes (see configfs_attach_group() and configfs_detach_group()).
86 * We put default groups i_mutexes in separate classes according to their depth
87 * from the youngest non-default group ancestor.
88 *
89 * For a non-default group A having default groups A/B, A/C, and A/C/D, default
90 * groups A/B and A/C will have their inode's mutex in class
91 * default_group_class[0], and default group A/C/D will be in
92 * default_group_class[1].
93 *
94 * The lock classes are declared and assigned in inode.c, according to the
95 * s_depth value.
96 * The s_depth value is initialized to -1, adjusted to >= 0 when attaching
97 * default groups, and reset to -1 when all default groups are attached. During
98 * attachment, if configfs_create() sees s_depth > 0, the lock class of the new
99 * inode's mutex is set to default_group_class[s_depth - 1].
100 */
101
102static void configfs_init_dirent_depth(struct configfs_dirent *sd)
103{
104 sd->s_depth = -1;
105}
106
107static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd,
108 struct configfs_dirent *sd)
109{
110 int parent_depth = parent_sd->s_depth;
111
112 if (parent_depth >= 0)
113 sd->s_depth = parent_depth + 1;
114}
115
116static void
117configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd)
118{
119 /*
120 * item's i_mutex class is already setup, so s_depth is now only
121 * used to set new sub-directories s_depth, which is always done
122 * with item's i_mutex locked.
123 */
124 /*
125 * sd->s_depth == -1 iff we are a non default group.
126 * else (we are a default group) sd->s_depth > 0 (see
127 * create_dir()).
128 */
129 if (sd->s_depth == -1)
130 /*
131 * We are a non default group and we are going to create
132 * default groups.
133 */
134 sd->s_depth = 0;
135}
136
137static void
138configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd)
139{
140 /* We will not create default groups anymore. */
141 sd->s_depth = -1;
142}
143
144#else /* CONFIG_LOCKDEP */
145
146static void configfs_init_dirent_depth(struct configfs_dirent *sd)
147{
148}
149
150static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd,
151 struct configfs_dirent *sd)
152{
153}
154
155static void
156configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd)
157{
158}
159
160static void
161configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd)
162{
163}
164
165#endif /* CONFIG_LOCKDEP */
166
Joel Becker7063fbf2005-12-15 14:29:43 -0800167/*
168 * Allocates a new configfs_dirent and links it to the parent configfs_dirent
169 */
Louis Rilling420118c2009-01-28 19:18:33 +0100170static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *parent_sd,
171 void *element, int type)
Joel Becker7063fbf2005-12-15 14:29:43 -0800172{
173 struct configfs_dirent * sd;
174
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800175 sd = kmem_cache_zalloc(configfs_dir_cachep, GFP_KERNEL);
Joel Becker7063fbf2005-12-15 14:29:43 -0800176 if (!sd)
Louis Rilling107ed402008-06-16 19:01:00 +0200177 return ERR_PTR(-ENOMEM);
Joel Becker7063fbf2005-12-15 14:29:43 -0800178
Joel Becker7063fbf2005-12-15 14:29:43 -0800179 atomic_set(&sd->s_count, 1);
180 INIT_LIST_HEAD(&sd->s_links);
181 INIT_LIST_HEAD(&sd->s_children);
Joel Becker7063fbf2005-12-15 14:29:43 -0800182 sd->s_element = element;
Louis Rilling420118c2009-01-28 19:18:33 +0100183 sd->s_type = type;
Louis Rillinge74cc062009-01-28 19:18:32 +0100184 configfs_init_dirent_depth(sd);
Louis Rilling6f610762008-06-16 19:00:58 +0200185 spin_lock(&configfs_dirent_lock);
Louis Rillingb3e76af2008-06-16 19:01:01 +0200186 if (parent_sd->s_type & CONFIGFS_USET_DROPPING) {
187 spin_unlock(&configfs_dirent_lock);
188 kmem_cache_free(configfs_dir_cachep, sd);
189 return ERR_PTR(-ENOENT);
190 }
Louis Rilling6f610762008-06-16 19:00:58 +0200191 list_add(&sd->s_sibling, &parent_sd->s_children);
192 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800193
194 return sd;
195}
196
Joel Beckerb4c98f62006-09-13 11:01:19 -0700197/*
198 *
199 * Return -EEXIST if there is already a configfs element with the same
200 * name for the same parent.
201 *
202 * called with parent inode's i_mutex held
203 */
Adrian Bunk58d206c2006-11-20 03:24:00 +0100204static int configfs_dirent_exists(struct configfs_dirent *parent_sd,
205 const unsigned char *new)
Joel Beckerb4c98f62006-09-13 11:01:19 -0700206{
207 struct configfs_dirent * sd;
208
209 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
210 if (sd->s_element) {
211 const unsigned char *existing = configfs_get_name(sd);
212 if (strcmp(existing, new))
213 continue;
214 else
215 return -EEXIST;
216 }
217 }
218
219 return 0;
220}
221
222
Joel Becker7063fbf2005-12-15 14:29:43 -0800223int configfs_make_dirent(struct configfs_dirent * parent_sd,
224 struct dentry * dentry, void * element,
225 umode_t mode, int type)
226{
227 struct configfs_dirent * sd;
228
Louis Rilling420118c2009-01-28 19:18:33 +0100229 sd = configfs_new_dirent(parent_sd, element, type);
Louis Rilling107ed402008-06-16 19:01:00 +0200230 if (IS_ERR(sd))
231 return PTR_ERR(sd);
Joel Becker7063fbf2005-12-15 14:29:43 -0800232
233 sd->s_mode = mode;
Joel Becker7063fbf2005-12-15 14:29:43 -0800234 sd->s_dentry = dentry;
235 if (dentry) {
236 dentry->d_fsdata = configfs_get(sd);
237 dentry->d_op = &configfs_dentry_ops;
238 }
239
240 return 0;
241}
242
243static int init_dir(struct inode * inode)
244{
245 inode->i_op = &configfs_dir_inode_operations;
246 inode->i_fop = &configfs_dir_operations;
247
248 /* directory inodes start off with i_nlink == 2 (for "." entry) */
Dave Hansend8c76e62006-09-30 23:29:04 -0700249 inc_nlink(inode);
Joel Becker7063fbf2005-12-15 14:29:43 -0800250 return 0;
251}
252
Dave Hansence8d2cd2007-10-16 23:31:13 -0700253static int configfs_init_file(struct inode * inode)
Joel Becker7063fbf2005-12-15 14:29:43 -0800254{
255 inode->i_size = PAGE_SIZE;
256 inode->i_fop = &configfs_file_operations;
257 return 0;
258}
259
260static int init_symlink(struct inode * inode)
261{
262 inode->i_op = &configfs_symlink_inode_operations;
263 return 0;
264}
265
266static int create_dir(struct config_item * k, struct dentry * p,
267 struct dentry * d)
268{
269 int error;
270 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
271
Joel Beckerb4c98f62006-09-13 11:01:19 -0700272 error = configfs_dirent_exists(p->d_fsdata, d->d_name.name);
273 if (!error)
274 error = configfs_make_dirent(p->d_fsdata, d, k, mode,
Louis Rilling2a109f22008-07-04 16:56:05 +0200275 CONFIGFS_DIR | CONFIGFS_USET_CREATING);
Joel Becker7063fbf2005-12-15 14:29:43 -0800276 if (!error) {
Louis Rillinge74cc062009-01-28 19:18:32 +0100277 configfs_set_dir_dirent_depth(p->d_fsdata, d->d_fsdata);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800278 error = configfs_create(d, mode, init_dir);
Joel Becker7063fbf2005-12-15 14:29:43 -0800279 if (!error) {
Dave Hansend8c76e62006-09-30 23:29:04 -0700280 inc_nlink(p->d_inode);
Joel Becker7063fbf2005-12-15 14:29:43 -0800281 (d)->d_op = &configfs_dentry_ops;
Joel Becker3d0f89b2006-01-25 13:31:07 -0800282 } else {
283 struct configfs_dirent *sd = d->d_fsdata;
284 if (sd) {
Louis Rilling6f610762008-06-16 19:00:58 +0200285 spin_lock(&configfs_dirent_lock);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800286 list_del_init(&sd->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +0200287 spin_unlock(&configfs_dirent_lock);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800288 configfs_put(sd);
289 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800290 }
291 }
292 return error;
293}
294
295
296/**
297 * configfs_create_dir - create a directory for an config_item.
298 * @item: config_itemwe're creating directory for.
299 * @dentry: config_item's dentry.
Louis Rilling2a109f22008-07-04 16:56:05 +0200300 *
301 * Note: user-created entries won't be allowed under this new directory
302 * until it is validated by configfs_dir_set_ready()
Joel Becker7063fbf2005-12-15 14:29:43 -0800303 */
304
305static int configfs_create_dir(struct config_item * item, struct dentry *dentry)
306{
307 struct dentry * parent;
308 int error = 0;
309
310 BUG_ON(!item);
311
312 if (item->ci_parent)
313 parent = item->ci_parent->ci_dentry;
314 else if (configfs_mount && configfs_mount->mnt_sb)
315 parent = configfs_mount->mnt_sb->s_root;
316 else
317 return -EFAULT;
318
319 error = create_dir(item,parent,dentry);
320 if (!error)
321 item->ci_dentry = dentry;
322 return error;
323}
324
Louis Rilling2a109f22008-07-04 16:56:05 +0200325/*
326 * Allow userspace to create new entries under a new directory created with
327 * configfs_create_dir(), and under all of its chidlren directories recursively.
328 * @sd configfs_dirent of the new directory to validate
329 *
330 * Caller must hold configfs_dirent_lock.
331 */
332static void configfs_dir_set_ready(struct configfs_dirent *sd)
333{
334 struct configfs_dirent *child_sd;
335
336 sd->s_type &= ~CONFIGFS_USET_CREATING;
337 list_for_each_entry(child_sd, &sd->s_children, s_sibling)
338 if (child_sd->s_type & CONFIGFS_USET_CREATING)
339 configfs_dir_set_ready(child_sd);
340}
341
342/*
343 * Check that a directory does not belong to a directory hierarchy being
344 * attached and not validated yet.
345 * @sd configfs_dirent of the directory to check
346 *
347 * @return non-zero iff the directory was validated
348 *
349 * Note: takes configfs_dirent_lock, so the result may change from false to true
350 * in two consecutive calls, but never from true to false.
351 */
352int configfs_dirent_is_ready(struct configfs_dirent *sd)
353{
354 int ret;
355
356 spin_lock(&configfs_dirent_lock);
357 ret = !(sd->s_type & CONFIGFS_USET_CREATING);
358 spin_unlock(&configfs_dirent_lock);
359
360 return ret;
361}
362
Joel Becker7063fbf2005-12-15 14:29:43 -0800363int configfs_create_link(struct configfs_symlink *sl,
364 struct dentry *parent,
365 struct dentry *dentry)
366{
367 int err = 0;
368 umode_t mode = S_IFLNK | S_IRWXUGO;
369
Joel Becker3d0f89b2006-01-25 13:31:07 -0800370 err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode,
371 CONFIGFS_ITEM_LINK);
Joel Becker7063fbf2005-12-15 14:29:43 -0800372 if (!err) {
Joel Becker3d0f89b2006-01-25 13:31:07 -0800373 err = configfs_create(dentry, mode, init_symlink);
Joel Becker7063fbf2005-12-15 14:29:43 -0800374 if (!err)
375 dentry->d_op = &configfs_dentry_ops;
Joel Becker3d0f89b2006-01-25 13:31:07 -0800376 else {
377 struct configfs_dirent *sd = dentry->d_fsdata;
378 if (sd) {
Louis Rilling6f610762008-06-16 19:00:58 +0200379 spin_lock(&configfs_dirent_lock);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800380 list_del_init(&sd->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +0200381 spin_unlock(&configfs_dirent_lock);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800382 configfs_put(sd);
383 }
384 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800385 }
386 return err;
387}
388
389static void remove_dir(struct dentry * d)
390{
391 struct dentry * parent = dget(d->d_parent);
392 struct configfs_dirent * sd;
393
394 sd = d->d_fsdata;
Louis Rilling6f610762008-06-16 19:00:58 +0200395 spin_lock(&configfs_dirent_lock);
Joel Beckere7515d02006-03-10 11:42:30 -0800396 list_del_init(&sd->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +0200397 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800398 configfs_put(sd);
399 if (d->d_inode)
400 simple_rmdir(parent->d_inode,d);
401
402 pr_debug(" o %s removing done (%d)\n",d->d_name.name,
403 atomic_read(&d->d_count));
404
405 dput(parent);
406}
407
408/**
409 * configfs_remove_dir - remove an config_item's directory.
410 * @item: config_item we're removing.
411 *
412 * The only thing special about this is that we remove any files in
413 * the directory before we remove the directory, and we've inlined
414 * what used to be configfs_rmdir() below, instead of calling separately.
Louis Rilling2e2ce172008-07-04 16:56:06 +0200415 *
416 * Caller holds the mutex of the item's inode
Joel Becker7063fbf2005-12-15 14:29:43 -0800417 */
418
419static void configfs_remove_dir(struct config_item * item)
420{
421 struct dentry * dentry = dget(item->ci_dentry);
422
423 if (!dentry)
424 return;
425
426 remove_dir(dentry);
427 /**
428 * Drop reference from dget() on entrance.
429 */
430 dput(dentry);
431}
432
433
434/* attaches attribute's configfs_dirent to the dentry corresponding to the
435 * attribute file
436 */
437static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry)
438{
439 struct configfs_attribute * attr = sd->s_element;
440 int error;
441
Joel Becker7063fbf2005-12-15 14:29:43 -0800442 dentry->d_fsdata = configfs_get(sd);
443 sd->s_dentry = dentry;
Dave Hansence8d2cd2007-10-16 23:31:13 -0700444 error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG,
445 configfs_init_file);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800446 if (error) {
447 configfs_put(sd);
448 return error;
449 }
450
451 dentry->d_op = &configfs_dentry_ops;
Joel Becker7063fbf2005-12-15 14:29:43 -0800452 d_rehash(dentry);
453
454 return 0;
455}
456
457static struct dentry * configfs_lookup(struct inode *dir,
458 struct dentry *dentry,
459 struct nameidata *nd)
460{
461 struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
462 struct configfs_dirent * sd;
463 int found = 0;
Louis Rilling2a109f22008-07-04 16:56:05 +0200464 int err;
465
466 /*
467 * Fake invisibility if dir belongs to a group/default groups hierarchy
468 * being attached
469 *
470 * This forbids userspace to read/write attributes of items which may
471 * not complete their initialization, since the dentries of the
472 * attributes won't be instantiated.
473 */
474 err = -ENOENT;
475 if (!configfs_dirent_is_ready(parent_sd))
476 goto out;
Joel Becker7063fbf2005-12-15 14:29:43 -0800477
478 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
479 if (sd->s_type & CONFIGFS_NOT_PINNED) {
480 const unsigned char * name = configfs_get_name(sd);
481
482 if (strcmp(name, dentry->d_name.name))
483 continue;
484
485 found = 1;
486 err = configfs_attach_attr(sd, dentry);
487 break;
488 }
489 }
490
491 if (!found) {
492 /*
493 * If it doesn't exist and it isn't a NOT_PINNED item,
494 * it must be negative.
495 */
496 return simple_lookup(dir, dentry, nd);
497 }
498
Louis Rilling2a109f22008-07-04 16:56:05 +0200499out:
Joel Becker7063fbf2005-12-15 14:29:43 -0800500 return ERR_PTR(err);
501}
502
503/*
504 * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are
Louis Rillingb3e76af2008-06-16 19:01:01 +0200505 * attributes and are removed by rmdir(). We recurse, setting
506 * CONFIGFS_USET_DROPPING on all children that are candidates for
507 * default detach.
508 * If there is an error, the caller will reset the flags via
509 * configfs_detach_rollback().
Joel Becker7063fbf2005-12-15 14:29:43 -0800510 */
Louis Rilling6d8344b2008-06-16 19:01:02 +0200511static int configfs_detach_prep(struct dentry *dentry, struct mutex **wait_mutex)
Joel Becker7063fbf2005-12-15 14:29:43 -0800512{
513 struct configfs_dirent *parent_sd = dentry->d_fsdata;
514 struct configfs_dirent *sd;
515 int ret;
516
Louis Rilling4768e9b2008-06-23 14:16:17 +0200517 /* Mark that we're trying to drop the group */
518 parent_sd->s_type |= CONFIGFS_USET_DROPPING;
519
Joel Becker7063fbf2005-12-15 14:29:43 -0800520 ret = -EBUSY;
521 if (!list_empty(&parent_sd->s_links))
522 goto out;
523
524 ret = 0;
525 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
Louis Rilling99cefda2008-06-27 13:10:25 +0200526 if (!sd->s_element ||
527 (sd->s_type & CONFIGFS_NOT_PINNED))
Joel Becker7063fbf2005-12-15 14:29:43 -0800528 continue;
529 if (sd->s_type & CONFIGFS_USET_DEFAULT) {
Louis Rilling6d8344b2008-06-16 19:01:02 +0200530 /* Abort if racing with mkdir() */
531 if (sd->s_type & CONFIGFS_USET_IN_MKDIR) {
532 if (wait_mutex)
533 *wait_mutex = &sd->s_dentry->d_inode->i_mutex;
534 return -EAGAIN;
535 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800536
Joel Becker631d1fe2007-06-18 18:06:09 -0700537 /*
538 * Yup, recursive. If there's a problem, blame
539 * deep nesting of default_groups
540 */
Louis Rilling6d8344b2008-06-16 19:01:02 +0200541 ret = configfs_detach_prep(sd->s_dentry, wait_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -0800542 if (!ret)
Joel Beckere7515d02006-03-10 11:42:30 -0800543 continue;
Joel Becker7063fbf2005-12-15 14:29:43 -0800544 } else
545 ret = -ENOTEMPTY;
546
547 break;
548 }
549
550out:
551 return ret;
552}
553
554/*
Louis Rillingb3e76af2008-06-16 19:01:01 +0200555 * Walk the tree, resetting CONFIGFS_USET_DROPPING wherever it was
Joel Becker7063fbf2005-12-15 14:29:43 -0800556 * set.
557 */
558static void configfs_detach_rollback(struct dentry *dentry)
559{
560 struct configfs_dirent *parent_sd = dentry->d_fsdata;
561 struct configfs_dirent *sd;
562
Louis Rilling4768e9b2008-06-23 14:16:17 +0200563 parent_sd->s_type &= ~CONFIGFS_USET_DROPPING;
564
565 list_for_each_entry(sd, &parent_sd->s_children, s_sibling)
566 if (sd->s_type & CONFIGFS_USET_DEFAULT)
Joel Becker7063fbf2005-12-15 14:29:43 -0800567 configfs_detach_rollback(sd->s_dentry);
Joel Becker7063fbf2005-12-15 14:29:43 -0800568}
569
570static void detach_attrs(struct config_item * item)
571{
572 struct dentry * dentry = dget(item->ci_dentry);
573 struct configfs_dirent * parent_sd;
574 struct configfs_dirent * sd, * tmp;
575
576 if (!dentry)
577 return;
578
579 pr_debug("configfs %s: dropping attrs for dir\n",
580 dentry->d_name.name);
581
582 parent_sd = dentry->d_fsdata;
583 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
584 if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED))
585 continue;
Louis Rilling6f610762008-06-16 19:00:58 +0200586 spin_lock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800587 list_del_init(&sd->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +0200588 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800589 configfs_drop_dentry(sd, dentry);
590 configfs_put(sd);
591 }
592
593 /**
594 * Drop reference from dget() on entrance.
595 */
596 dput(dentry);
597}
598
599static int populate_attrs(struct config_item *item)
600{
601 struct config_item_type *t = item->ci_type;
602 struct configfs_attribute *attr;
603 int error = 0;
604 int i;
605
606 if (!t)
607 return -EINVAL;
608 if (t->ct_attrs) {
609 for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) {
610 if ((error = configfs_create_file(item, attr)))
611 break;
612 }
613 }
614
615 if (error)
616 detach_attrs(item);
617
618 return error;
619}
620
621static int configfs_attach_group(struct config_item *parent_item,
622 struct config_item *item,
623 struct dentry *dentry);
624static void configfs_detach_group(struct config_item *item);
625
626static void detach_groups(struct config_group *group)
627{
628 struct dentry * dentry = dget(group->cg_item.ci_dentry);
629 struct dentry *child;
630 struct configfs_dirent *parent_sd;
631 struct configfs_dirent *sd, *tmp;
632
633 if (!dentry)
634 return;
635
636 parent_sd = dentry->d_fsdata;
637 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
638 if (!sd->s_element ||
639 !(sd->s_type & CONFIGFS_USET_DEFAULT))
640 continue;
641
642 child = sd->s_dentry;
643
Louis Rillingb3e76af2008-06-16 19:01:01 +0200644 mutex_lock(&child->d_inode->i_mutex);
645
Joel Becker7063fbf2005-12-15 14:29:43 -0800646 configfs_detach_group(sd->s_element);
647 child->d_inode->i_flags |= S_DEAD;
648
Louis Rillingb3e76af2008-06-16 19:01:01 +0200649 mutex_unlock(&child->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -0800650
651 d_delete(child);
652 dput(child);
653 }
654
655 /**
656 * Drop reference from dget() on entrance.
657 */
658 dput(dentry);
659}
660
661/*
662 * This fakes mkdir(2) on a default_groups[] entry. It
663 * creates a dentry, attachs it, and then does fixup
664 * on the sd->s_type.
665 *
666 * We could, perhaps, tweak our parent's ->mkdir for a minute and
667 * try using vfs_mkdir. Just a thought.
668 */
669static int create_default_group(struct config_group *parent_group,
670 struct config_group *group)
671{
672 int ret;
673 struct qstr name;
674 struct configfs_dirent *sd;
675 /* We trust the caller holds a reference to parent */
676 struct dentry *child, *parent = parent_group->cg_item.ci_dentry;
677
678 if (!group->cg_item.ci_name)
679 group->cg_item.ci_name = group->cg_item.ci_namebuf;
680 name.name = group->cg_item.ci_name;
681 name.len = strlen(name.name);
682 name.hash = full_name_hash(name.name, name.len);
683
684 ret = -ENOMEM;
685 child = d_alloc(parent, &name);
686 if (child) {
687 d_add(child, NULL);
688
689 ret = configfs_attach_group(&parent_group->cg_item,
690 &group->cg_item, child);
691 if (!ret) {
692 sd = child->d_fsdata;
693 sd->s_type |= CONFIGFS_USET_DEFAULT;
694 } else {
695 d_delete(child);
696 dput(child);
697 }
698 }
699
700 return ret;
701}
702
703static int populate_groups(struct config_group *group)
704{
705 struct config_group *new_group;
Joel Becker7063fbf2005-12-15 14:29:43 -0800706 int ret = 0;
707 int i;
708
Eric Sesterhenncbca6922006-03-23 00:36:54 +0100709 if (group->default_groups) {
Joel Becker7063fbf2005-12-15 14:29:43 -0800710 for (i = 0; group->default_groups[i]; i++) {
711 new_group = group->default_groups[i];
712
713 ret = create_default_group(group, new_group);
Louis Rilling2e2ce172008-07-04 16:56:06 +0200714 if (ret) {
715 detach_groups(group);
Joel Becker7063fbf2005-12-15 14:29:43 -0800716 break;
Louis Rilling2e2ce172008-07-04 16:56:06 +0200717 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800718 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800719 }
720
Joel Becker7063fbf2005-12-15 14:29:43 -0800721 return ret;
722}
723
724/*
725 * All of link_obj/unlink_obj/link_group/unlink_group require that
Joel Beckere6bd07a2007-07-06 23:33:17 -0700726 * subsys->su_mutex is held.
Joel Becker7063fbf2005-12-15 14:29:43 -0800727 */
728
729static void unlink_obj(struct config_item *item)
730{
731 struct config_group *group;
732
733 group = item->ci_group;
734 if (group) {
735 list_del_init(&item->ci_entry);
736
737 item->ci_group = NULL;
738 item->ci_parent = NULL;
Joel Beckereed7a0d2006-04-11 21:37:20 -0700739
740 /* Drop the reference for ci_entry */
Joel Becker7063fbf2005-12-15 14:29:43 -0800741 config_item_put(item);
742
Joel Beckereed7a0d2006-04-11 21:37:20 -0700743 /* Drop the reference for ci_parent */
Joel Becker7063fbf2005-12-15 14:29:43 -0800744 config_group_put(group);
745 }
746}
747
748static void link_obj(struct config_item *parent_item, struct config_item *item)
749{
Joel Beckereed7a0d2006-04-11 21:37:20 -0700750 /*
751 * Parent seems redundant with group, but it makes certain
752 * traversals much nicer.
753 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800754 item->ci_parent = parent_item;
Joel Beckereed7a0d2006-04-11 21:37:20 -0700755
756 /*
757 * We hold a reference on the parent for the child's ci_parent
758 * link.
759 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800760 item->ci_group = config_group_get(to_config_group(parent_item));
761 list_add_tail(&item->ci_entry, &item->ci_group->cg_children);
762
Joel Beckereed7a0d2006-04-11 21:37:20 -0700763 /*
764 * We hold a reference on the child for ci_entry on the parent's
765 * cg_children
766 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800767 config_item_get(item);
768}
769
770static void unlink_group(struct config_group *group)
771{
772 int i;
773 struct config_group *new_group;
774
775 if (group->default_groups) {
776 for (i = 0; group->default_groups[i]; i++) {
777 new_group = group->default_groups[i];
778 unlink_group(new_group);
779 }
780 }
781
782 group->cg_subsys = NULL;
783 unlink_obj(&group->cg_item);
784}
785
786static void link_group(struct config_group *parent_group, struct config_group *group)
787{
788 int i;
789 struct config_group *new_group;
790 struct configfs_subsystem *subsys = NULL; /* gcc is a turd */
791
792 link_obj(&parent_group->cg_item, &group->cg_item);
793
794 if (parent_group->cg_subsys)
795 subsys = parent_group->cg_subsys;
796 else if (configfs_is_root(&parent_group->cg_item))
797 subsys = to_configfs_subsystem(group);
798 else
799 BUG();
800 group->cg_subsys = subsys;
801
802 if (group->default_groups) {
803 for (i = 0; group->default_groups[i]; i++) {
804 new_group = group->default_groups[i];
805 link_group(group, new_group);
806 }
807 }
808}
809
810/*
811 * The goal is that configfs_attach_item() (and
812 * configfs_attach_group()) can be called from either the VFS or this
813 * module. That is, they assume that the items have been created,
814 * the dentry allocated, and the dcache is all ready to go.
815 *
816 * If they fail, they must clean up after themselves as if they
817 * had never been called. The caller (VFS or local function) will
818 * handle cleaning up the dcache bits.
819 *
820 * configfs_detach_group() and configfs_detach_item() behave similarly on
821 * the way out. They assume that the proper semaphores are held, they
822 * clean up the configfs items, and they expect their callers will
823 * handle the dcache bits.
824 */
825static int configfs_attach_item(struct config_item *parent_item,
826 struct config_item *item,
827 struct dentry *dentry)
828{
829 int ret;
830
831 ret = configfs_create_dir(item, dentry);
832 if (!ret) {
833 ret = populate_attrs(item);
834 if (ret) {
Louis Rilling2e2ce172008-07-04 16:56:06 +0200835 /*
836 * We are going to remove an inode and its dentry but
837 * the VFS may already have hit and used them. Thus,
838 * we must lock them as rmdir() would.
839 */
840 mutex_lock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -0800841 configfs_remove_dir(item);
Louis Rilling2e2ce172008-07-04 16:56:06 +0200842 dentry->d_inode->i_flags |= S_DEAD;
843 mutex_unlock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -0800844 d_delete(dentry);
845 }
846 }
847
848 return ret;
849}
850
Louis Rilling2e2ce172008-07-04 16:56:06 +0200851/* Caller holds the mutex of the item's inode */
Joel Becker7063fbf2005-12-15 14:29:43 -0800852static void configfs_detach_item(struct config_item *item)
853{
854 detach_attrs(item);
855 configfs_remove_dir(item);
856}
857
858static int configfs_attach_group(struct config_item *parent_item,
859 struct config_item *item,
860 struct dentry *dentry)
861{
862 int ret;
863 struct configfs_dirent *sd;
864
865 ret = configfs_attach_item(parent_item, item, dentry);
866 if (!ret) {
867 sd = dentry->d_fsdata;
868 sd->s_type |= CONFIGFS_USET_DIR;
869
Louis Rilling2e2ce172008-07-04 16:56:06 +0200870 /*
871 * FYI, we're faking mkdir in populate_groups()
872 * We must lock the group's inode to avoid races with the VFS
873 * which can already hit the inode and try to add/remove entries
874 * under it.
875 *
876 * We must also lock the inode to remove it safely in case of
877 * error, as rmdir() would.
878 */
879 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD);
Louis Rillinge74cc062009-01-28 19:18:32 +0100880 configfs_adjust_dir_dirent_depth_before_populate(sd);
Joel Becker7063fbf2005-12-15 14:29:43 -0800881 ret = populate_groups(to_config_group(item));
882 if (ret) {
883 configfs_detach_item(item);
Louis Rilling2e2ce172008-07-04 16:56:06 +0200884 dentry->d_inode->i_flags |= S_DEAD;
Joel Becker7063fbf2005-12-15 14:29:43 -0800885 }
Louis Rillinge74cc062009-01-28 19:18:32 +0100886 configfs_adjust_dir_dirent_depth_after_populate(sd);
Louis Rilling2e2ce172008-07-04 16:56:06 +0200887 mutex_unlock(&dentry->d_inode->i_mutex);
888 if (ret)
889 d_delete(dentry);
Joel Becker7063fbf2005-12-15 14:29:43 -0800890 }
891
892 return ret;
893}
894
Louis Rilling2e2ce172008-07-04 16:56:06 +0200895/* Caller holds the mutex of the group's inode */
Joel Becker7063fbf2005-12-15 14:29:43 -0800896static void configfs_detach_group(struct config_item *item)
897{
898 detach_groups(to_config_group(item));
899 configfs_detach_item(item);
900}
901
902/*
Joel Becker299894c2006-10-06 17:33:23 -0700903 * After the item has been detached from the filesystem view, we are
904 * ready to tear it out of the hierarchy. Notify the client before
905 * we do that so they can perform any cleanup that requires
906 * navigating the hierarchy. A client does not need to provide this
907 * callback. The subsystem semaphore MUST be held by the caller, and
908 * references must be valid for both items. It also assumes the
909 * caller has validated ci_type.
910 */
911static void client_disconnect_notify(struct config_item *parent_item,
912 struct config_item *item)
913{
914 struct config_item_type *type;
915
916 type = parent_item->ci_type;
917 BUG_ON(!type);
918
919 if (type->ct_group_ops && type->ct_group_ops->disconnect_notify)
920 type->ct_group_ops->disconnect_notify(to_config_group(parent_item),
921 item);
922}
923
924/*
Joel Becker7063fbf2005-12-15 14:29:43 -0800925 * Drop the initial reference from make_item()/make_group()
926 * This function assumes that reference is held on item
927 * and that item holds a valid reference to the parent. Also, it
928 * assumes the caller has validated ci_type.
929 */
930static void client_drop_item(struct config_item *parent_item,
931 struct config_item *item)
932{
933 struct config_item_type *type;
934
935 type = parent_item->ci_type;
936 BUG_ON(!type);
937
Joel Beckereed7a0d2006-04-11 21:37:20 -0700938 /*
939 * If ->drop_item() exists, it is responsible for the
940 * config_item_put().
941 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800942 if (type->ct_group_ops && type->ct_group_ops->drop_item)
943 type->ct_group_ops->drop_item(to_config_group(parent_item),
Joel Becker299894c2006-10-06 17:33:23 -0700944 item);
Joel Becker7063fbf2005-12-15 14:29:43 -0800945 else
946 config_item_put(item);
947}
948
Joel Becker631d1fe2007-06-18 18:06:09 -0700949#ifdef DEBUG
950static void configfs_dump_one(struct configfs_dirent *sd, int level)
951{
952 printk(KERN_INFO "%*s\"%s\":\n", level, " ", configfs_get_name(sd));
953
954#define type_print(_type) if (sd->s_type & _type) printk(KERN_INFO "%*s %s\n", level, " ", #_type);
955 type_print(CONFIGFS_ROOT);
956 type_print(CONFIGFS_DIR);
957 type_print(CONFIGFS_ITEM_ATTR);
958 type_print(CONFIGFS_ITEM_LINK);
959 type_print(CONFIGFS_USET_DIR);
960 type_print(CONFIGFS_USET_DEFAULT);
961 type_print(CONFIGFS_USET_DROPPING);
962#undef type_print
963}
964
965static int configfs_dump(struct configfs_dirent *sd, int level)
966{
967 struct configfs_dirent *child_sd;
968 int ret = 0;
969
970 configfs_dump_one(sd, level);
971
972 if (!(sd->s_type & (CONFIGFS_DIR|CONFIGFS_ROOT)))
973 return 0;
974
975 list_for_each_entry(child_sd, &sd->s_children, s_sibling) {
976 ret = configfs_dump(child_sd, level + 2);
977 if (ret)
978 break;
979 }
980
981 return ret;
982}
983#endif
984
985
986/*
987 * configfs_depend_item() and configfs_undepend_item()
988 *
989 * WARNING: Do not call these from a configfs callback!
990 *
991 * This describes these functions and their helpers.
992 *
993 * Allow another kernel system to depend on a config_item. If this
994 * happens, the item cannot go away until the dependant can live without
995 * it. The idea is to give client modules as simple an interface as
996 * possible. When a system asks them to depend on an item, they just
997 * call configfs_depend_item(). If the item is live and the client
998 * driver is in good shape, we'll happily do the work for them.
999 *
1000 * Why is the locking complex? Because configfs uses the VFS to handle
1001 * all locking, but this function is called outside the normal
1002 * VFS->configfs path. So it must take VFS locks to prevent the
1003 * VFS->configfs stuff (configfs_mkdir(), configfs_rmdir(), etc). This is
1004 * why you can't call these functions underneath configfs callbacks.
1005 *
1006 * Note, btw, that this can be called at *any* time, even when a configfs
1007 * subsystem isn't registered, or when configfs is loading or unloading.
1008 * Just like configfs_register_subsystem(). So we take the same
Louis Rilling420118c2009-01-28 19:18:33 +01001009 * precautions. We pin the filesystem. We lock configfs_dirent_lock.
1010 * If we can find the target item in the
Joel Becker631d1fe2007-06-18 18:06:09 -07001011 * configfs tree, it must be part of the subsystem tree as well, so we
Louis Rilling420118c2009-01-28 19:18:33 +01001012 * do not need the subsystem semaphore. Holding configfs_dirent_lock helps
1013 * locking out mkdir() and rmdir(), who might be racing us.
Joel Becker631d1fe2007-06-18 18:06:09 -07001014 */
1015
1016/*
1017 * configfs_depend_prep()
1018 *
1019 * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are
1020 * attributes. This is similar but not the same to configfs_detach_prep().
1021 * Note that configfs_detach_prep() expects the parent to be locked when it
1022 * is called, but we lock the parent *inside* configfs_depend_prep(). We
1023 * do that so we can unlock it if we find nothing.
1024 *
1025 * Here we do a depth-first search of the dentry hierarchy looking for
Louis Rilling420118c2009-01-28 19:18:33 +01001026 * our object.
1027 * We deliberately ignore items tagged as dropping since they are virtually
1028 * dead, as well as items in the middle of attachment since they virtually
1029 * do not exist yet. This completes the locking out of racing mkdir() and
1030 * rmdir().
1031 * Note: subdirectories in the middle of attachment start with s_type =
1032 * CONFIGFS_DIR|CONFIGFS_USET_CREATING set by create_dir(). When
1033 * CONFIGFS_USET_CREATING is set, we ignore the item. The actual set of
1034 * s_type is in configfs_new_dirent(), which has configfs_dirent_lock.
Joel Becker631d1fe2007-06-18 18:06:09 -07001035 *
Louis Rilling420118c2009-01-28 19:18:33 +01001036 * If the target is not found, -ENOENT is bubbled up.
Joel Becker631d1fe2007-06-18 18:06:09 -07001037 *
1038 * This adds a requirement that all config_items be unique!
1039 *
Louis Rilling420118c2009-01-28 19:18:33 +01001040 * This is recursive. There isn't
Joel Becker631d1fe2007-06-18 18:06:09 -07001041 * much on the stack, though, so folks that need this function - be careful
1042 * about your stack! Patches will be accepted to make it iterative.
1043 */
1044static int configfs_depend_prep(struct dentry *origin,
1045 struct config_item *target)
1046{
1047 struct configfs_dirent *child_sd, *sd = origin->d_fsdata;
1048 int ret = 0;
1049
1050 BUG_ON(!origin || !sd);
1051
Joel Becker631d1fe2007-06-18 18:06:09 -07001052 if (sd->s_element == target) /* Boo-yah */
1053 goto out;
1054
1055 list_for_each_entry(child_sd, &sd->s_children, s_sibling) {
Louis Rilling420118c2009-01-28 19:18:33 +01001056 if ((child_sd->s_type & CONFIGFS_DIR) &&
1057 !(child_sd->s_type & CONFIGFS_USET_DROPPING) &&
1058 !(child_sd->s_type & CONFIGFS_USET_CREATING)) {
Joel Becker631d1fe2007-06-18 18:06:09 -07001059 ret = configfs_depend_prep(child_sd->s_dentry,
1060 target);
1061 if (!ret)
1062 goto out; /* Child path boo-yah */
1063 }
1064 }
1065
1066 /* We looped all our children and didn't find target */
Joel Becker631d1fe2007-06-18 18:06:09 -07001067 ret = -ENOENT;
1068
1069out:
1070 return ret;
1071}
1072
Joel Becker631d1fe2007-06-18 18:06:09 -07001073int configfs_depend_item(struct configfs_subsystem *subsys,
1074 struct config_item *target)
1075{
1076 int ret;
1077 struct configfs_dirent *p, *root_sd, *subsys_sd = NULL;
1078 struct config_item *s_item = &subsys->su_group.cg_item;
1079
1080 /*
1081 * Pin the configfs filesystem. This means we can safely access
1082 * the root of the configfs filesystem.
1083 */
1084 ret = configfs_pin_fs();
1085 if (ret)
1086 return ret;
1087
1088 /*
1089 * Next, lock the root directory. We're going to check that the
1090 * subsystem is really registered, and so we need to lock out
1091 * configfs_[un]register_subsystem().
1092 */
1093 mutex_lock(&configfs_sb->s_root->d_inode->i_mutex);
1094
1095 root_sd = configfs_sb->s_root->d_fsdata;
1096
1097 list_for_each_entry(p, &root_sd->s_children, s_sibling) {
1098 if (p->s_type & CONFIGFS_DIR) {
1099 if (p->s_element == s_item) {
1100 subsys_sd = p;
1101 break;
1102 }
1103 }
1104 }
1105
1106 if (!subsys_sd) {
1107 ret = -ENOENT;
1108 goto out_unlock_fs;
1109 }
1110
1111 /* Ok, now we can trust subsys/s_item */
1112
Louis Rilling420118c2009-01-28 19:18:33 +01001113 spin_lock(&configfs_dirent_lock);
1114 /* Scan the tree, return 0 if found */
Joel Becker631d1fe2007-06-18 18:06:09 -07001115 ret = configfs_depend_prep(subsys_sd->s_dentry, target);
1116 if (ret)
Louis Rilling420118c2009-01-28 19:18:33 +01001117 goto out_unlock_dirent_lock;
Joel Becker631d1fe2007-06-18 18:06:09 -07001118
Louis Rilling420118c2009-01-28 19:18:33 +01001119 /*
1120 * We are sure that the item is not about to be removed by rmdir(), and
1121 * not in the middle of attachment by mkdir().
1122 */
Joel Becker631d1fe2007-06-18 18:06:09 -07001123 p = target->ci_dentry->d_fsdata;
1124 p->s_dependent_count += 1;
1125
Louis Rilling420118c2009-01-28 19:18:33 +01001126out_unlock_dirent_lock:
1127 spin_unlock(&configfs_dirent_lock);
Joel Becker631d1fe2007-06-18 18:06:09 -07001128out_unlock_fs:
1129 mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
1130
1131 /*
1132 * If we succeeded, the fs is pinned via other methods. If not,
1133 * we're done with it anyway. So release_fs() is always right.
1134 */
1135 configfs_release_fs();
1136
1137 return ret;
1138}
1139EXPORT_SYMBOL(configfs_depend_item);
1140
1141/*
1142 * Release the dependent linkage. This is much simpler than
1143 * configfs_depend_item() because we know that that the client driver is
1144 * pinned, thus the subsystem is pinned, and therefore configfs is pinned.
1145 */
1146void configfs_undepend_item(struct configfs_subsystem *subsys,
1147 struct config_item *target)
1148{
1149 struct configfs_dirent *sd;
1150
1151 /*
Louis Rilling420118c2009-01-28 19:18:33 +01001152 * Since we can trust everything is pinned, we just need
1153 * configfs_dirent_lock.
Joel Becker631d1fe2007-06-18 18:06:09 -07001154 */
Louis Rilling420118c2009-01-28 19:18:33 +01001155 spin_lock(&configfs_dirent_lock);
Joel Becker631d1fe2007-06-18 18:06:09 -07001156
1157 sd = target->ci_dentry->d_fsdata;
1158 BUG_ON(sd->s_dependent_count < 1);
1159
1160 sd->s_dependent_count -= 1;
1161
1162 /*
1163 * After this unlock, we cannot trust the item to stay alive!
1164 * DO NOT REFERENCE item after this unlock.
1165 */
Louis Rilling420118c2009-01-28 19:18:33 +01001166 spin_unlock(&configfs_dirent_lock);
Joel Becker631d1fe2007-06-18 18:06:09 -07001167}
1168EXPORT_SYMBOL(configfs_undepend_item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001169
1170static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
1171{
Joel Beckera6795e92008-07-17 15:21:29 -07001172 int ret = 0;
1173 int module_got = 0;
1174 struct config_group *group = NULL;
1175 struct config_item *item = NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -08001176 struct config_item *parent_item;
1177 struct configfs_subsystem *subsys;
1178 struct configfs_dirent *sd;
1179 struct config_item_type *type;
Joel Becker70526b62008-06-17 15:34:32 -07001180 struct module *subsys_owner = NULL, *new_item_owner = NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -08001181 char *name;
1182
Joel Becker84efad12006-03-27 18:46:09 -08001183 if (dentry->d_parent == configfs_sb->s_root) {
1184 ret = -EPERM;
1185 goto out;
1186 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001187
1188 sd = dentry->d_parent->d_fsdata;
Louis Rilling2a109f22008-07-04 16:56:05 +02001189
1190 /*
1191 * Fake invisibility if dir belongs to a group/default groups hierarchy
1192 * being attached
1193 */
1194 if (!configfs_dirent_is_ready(sd)) {
1195 ret = -ENOENT;
1196 goto out;
1197 }
1198
Joel Becker84efad12006-03-27 18:46:09 -08001199 if (!(sd->s_type & CONFIGFS_USET_DIR)) {
1200 ret = -EPERM;
1201 goto out;
1202 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001203
Joel Becker84efad12006-03-27 18:46:09 -08001204 /* Get a working ref for the duration of this function */
Joel Becker7063fbf2005-12-15 14:29:43 -08001205 parent_item = configfs_get_config_item(dentry->d_parent);
1206 type = parent_item->ci_type;
1207 subsys = to_config_group(parent_item)->cg_subsys;
1208 BUG_ON(!subsys);
1209
1210 if (!type || !type->ct_group_ops ||
1211 (!type->ct_group_ops->make_group &&
1212 !type->ct_group_ops->make_item)) {
Joel Becker84efad12006-03-27 18:46:09 -08001213 ret = -EPERM; /* Lack-of-mkdir returns -EPERM */
1214 goto out_put;
Joel Becker7063fbf2005-12-15 14:29:43 -08001215 }
1216
Joel Becker70526b62008-06-17 15:34:32 -07001217 /*
1218 * The subsystem may belong to a different module than the item
1219 * being created. We don't want to safely pin the new item but
1220 * fail to pin the subsystem it sits under.
1221 */
1222 if (!subsys->su_group.cg_item.ci_type) {
1223 ret = -EINVAL;
1224 goto out_put;
1225 }
1226 subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner;
1227 if (!try_module_get(subsys_owner)) {
1228 ret = -EINVAL;
1229 goto out_put;
1230 }
1231
Joel Becker7063fbf2005-12-15 14:29:43 -08001232 name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL);
1233 if (!name) {
Joel Becker84efad12006-03-27 18:46:09 -08001234 ret = -ENOMEM;
Joel Becker70526b62008-06-17 15:34:32 -07001235 goto out_subsys_put;
Joel Becker7063fbf2005-12-15 14:29:43 -08001236 }
Joel Becker84efad12006-03-27 18:46:09 -08001237
Joel Becker7063fbf2005-12-15 14:29:43 -08001238 snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name);
1239
Joel Beckere6bd07a2007-07-06 23:33:17 -07001240 mutex_lock(&subsys->su_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001241 if (type->ct_group_ops->make_group) {
Joel Beckerf89ab862008-07-17 14:53:48 -07001242 group = type->ct_group_ops->make_group(to_config_group(parent_item), name);
Joel Beckera6795e92008-07-17 15:21:29 -07001243 if (!group)
1244 group = ERR_PTR(-ENOMEM);
1245 if (!IS_ERR(group)) {
Joel Becker7063fbf2005-12-15 14:29:43 -08001246 link_group(to_config_group(parent_item), group);
1247 item = &group->cg_item;
Joel Beckera6795e92008-07-17 15:21:29 -07001248 } else
1249 ret = PTR_ERR(group);
Joel Becker7063fbf2005-12-15 14:29:43 -08001250 } else {
Joel Beckerf89ab862008-07-17 14:53:48 -07001251 item = type->ct_group_ops->make_item(to_config_group(parent_item), name);
Joel Beckera6795e92008-07-17 15:21:29 -07001252 if (!item)
1253 item = ERR_PTR(-ENOMEM);
1254 if (!IS_ERR(item))
Joel Becker7063fbf2005-12-15 14:29:43 -08001255 link_obj(parent_item, item);
Joel Beckera6795e92008-07-17 15:21:29 -07001256 else
1257 ret = PTR_ERR(item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001258 }
Joel Beckere6bd07a2007-07-06 23:33:17 -07001259 mutex_unlock(&subsys->su_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001260
1261 kfree(name);
Joel Beckera6795e92008-07-17 15:21:29 -07001262 if (ret) {
Joel Beckereed7a0d2006-04-11 21:37:20 -07001263 /*
Joel Beckerdacdd0e2008-07-17 16:54:19 -07001264 * If ret != 0, then link_obj() was never called.
Joel Beckereed7a0d2006-04-11 21:37:20 -07001265 * There are no extra references to clean up.
1266 */
Joel Becker70526b62008-06-17 15:34:32 -07001267 goto out_subsys_put;
Joel Becker7063fbf2005-12-15 14:29:43 -08001268 }
1269
Joel Beckereed7a0d2006-04-11 21:37:20 -07001270 /*
1271 * link_obj() has been called (via link_group() for groups).
1272 * From here on out, errors must clean that up.
1273 */
1274
Joel Becker7063fbf2005-12-15 14:29:43 -08001275 type = item->ci_type;
Joel Beckereed7a0d2006-04-11 21:37:20 -07001276 if (!type) {
1277 ret = -EINVAL;
1278 goto out_unlink;
1279 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001280
Joel Becker70526b62008-06-17 15:34:32 -07001281 new_item_owner = type->ct_owner;
1282 if (!try_module_get(new_item_owner)) {
Joel Beckereed7a0d2006-04-11 21:37:20 -07001283 ret = -EINVAL;
1284 goto out_unlink;
1285 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001286
Joel Beckereed7a0d2006-04-11 21:37:20 -07001287 /*
1288 * I hate doing it this way, but if there is
1289 * an error, module_put() probably should
1290 * happen after any cleanup.
1291 */
1292 module_got = 1;
1293
Louis Rilling6d8344b2008-06-16 19:01:02 +02001294 /*
1295 * Make racing rmdir() fail if it did not tag parent with
1296 * CONFIGFS_USET_DROPPING
1297 * Note: if CONFIGFS_USET_DROPPING is already set, attach_group() will
1298 * fail and let rmdir() terminate correctly
1299 */
1300 spin_lock(&configfs_dirent_lock);
1301 /* This will make configfs_detach_prep() fail */
1302 sd->s_type |= CONFIGFS_USET_IN_MKDIR;
1303 spin_unlock(&configfs_dirent_lock);
1304
Joel Beckereed7a0d2006-04-11 21:37:20 -07001305 if (group)
1306 ret = configfs_attach_group(parent_item, item, dentry);
1307 else
1308 ret = configfs_attach_item(parent_item, item, dentry);
1309
Louis Rilling6d8344b2008-06-16 19:01:02 +02001310 spin_lock(&configfs_dirent_lock);
1311 sd->s_type &= ~CONFIGFS_USET_IN_MKDIR;
Louis Rilling2a109f22008-07-04 16:56:05 +02001312 if (!ret)
1313 configfs_dir_set_ready(dentry->d_fsdata);
Louis Rilling6d8344b2008-06-16 19:01:02 +02001314 spin_unlock(&configfs_dirent_lock);
1315
Joel Beckereed7a0d2006-04-11 21:37:20 -07001316out_unlink:
1317 if (ret) {
1318 /* Tear down everything we built up */
Joel Beckere6bd07a2007-07-06 23:33:17 -07001319 mutex_lock(&subsys->su_mutex);
Joel Becker299894c2006-10-06 17:33:23 -07001320
1321 client_disconnect_notify(parent_item, item);
Joel Beckereed7a0d2006-04-11 21:37:20 -07001322 if (group)
1323 unlink_group(group);
1324 else
1325 unlink_obj(item);
1326 client_drop_item(parent_item, item);
Joel Becker299894c2006-10-06 17:33:23 -07001327
Joel Beckere6bd07a2007-07-06 23:33:17 -07001328 mutex_unlock(&subsys->su_mutex);
Joel Beckereed7a0d2006-04-11 21:37:20 -07001329
1330 if (module_got)
Joel Becker70526b62008-06-17 15:34:32 -07001331 module_put(new_item_owner);
Joel Becker7063fbf2005-12-15 14:29:43 -08001332 }
1333
Joel Becker70526b62008-06-17 15:34:32 -07001334out_subsys_put:
1335 if (ret)
1336 module_put(subsys_owner);
1337
Joel Becker84efad12006-03-27 18:46:09 -08001338out_put:
1339 /*
Joel Beckereed7a0d2006-04-11 21:37:20 -07001340 * link_obj()/link_group() took a reference from child->parent,
1341 * so the parent is safely pinned. We can drop our working
1342 * reference.
Joel Becker84efad12006-03-27 18:46:09 -08001343 */
1344 config_item_put(parent_item);
1345
1346out:
Joel Becker7063fbf2005-12-15 14:29:43 -08001347 return ret;
1348}
1349
1350static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
1351{
1352 struct config_item *parent_item;
1353 struct config_item *item;
1354 struct configfs_subsystem *subsys;
1355 struct configfs_dirent *sd;
Joel Becker70526b62008-06-17 15:34:32 -07001356 struct module *subsys_owner = NULL, *dead_item_owner = NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -08001357 int ret;
1358
1359 if (dentry->d_parent == configfs_sb->s_root)
1360 return -EPERM;
1361
1362 sd = dentry->d_fsdata;
1363 if (sd->s_type & CONFIGFS_USET_DEFAULT)
1364 return -EPERM;
1365
Joel Becker84efad12006-03-27 18:46:09 -08001366 /* Get a working ref until we have the child */
Joel Becker7063fbf2005-12-15 14:29:43 -08001367 parent_item = configfs_get_config_item(dentry->d_parent);
1368 subsys = to_config_group(parent_item)->cg_subsys;
1369 BUG_ON(!subsys);
1370
1371 if (!parent_item->ci_type) {
1372 config_item_put(parent_item);
1373 return -EINVAL;
1374 }
1375
Joel Becker70526b62008-06-17 15:34:32 -07001376 /* configfs_mkdir() shouldn't have allowed this */
1377 BUG_ON(!subsys->su_group.cg_item.ci_type);
1378 subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner;
1379
Louis Rilling9a73d782008-06-20 14:09:22 +02001380 /*
1381 * Ensure that no racing symlink() will make detach_prep() fail while
1382 * the new link is temporarily attached
1383 */
Louis Rilling6d8344b2008-06-16 19:01:02 +02001384 do {
1385 struct mutex *wait_mutex;
1386
Louis Rillingde6bf182008-08-15 12:37:23 -07001387 mutex_lock(&configfs_symlink_mutex);
1388 spin_lock(&configfs_dirent_lock);
Louis Rilling420118c2009-01-28 19:18:33 +01001389 /*
1390 * Here's where we check for dependents. We're protected by
1391 * configfs_dirent_lock.
1392 * If no dependent, atomically tag the item as dropping.
1393 */
1394 ret = sd->s_dependent_count ? -EBUSY : 0;
1395 if (!ret) {
1396 ret = configfs_detach_prep(dentry, &wait_mutex);
1397 if (ret)
1398 configfs_detach_rollback(dentry);
1399 }
Louis Rillingde6bf182008-08-15 12:37:23 -07001400 spin_unlock(&configfs_dirent_lock);
1401 mutex_unlock(&configfs_symlink_mutex);
1402
1403 if (ret) {
Louis Rilling6d8344b2008-06-16 19:01:02 +02001404 if (ret != -EAGAIN) {
1405 config_item_put(parent_item);
1406 return ret;
1407 }
1408
1409 /* Wait until the racing operation terminates */
1410 mutex_lock(wait_mutex);
1411 mutex_unlock(wait_mutex);
Louis Rilling6d8344b2008-06-16 19:01:02 +02001412 }
1413 } while (ret == -EAGAIN);
Joel Becker7063fbf2005-12-15 14:29:43 -08001414
Joel Becker84efad12006-03-27 18:46:09 -08001415 /* Get a working ref for the duration of this function */
Joel Becker7063fbf2005-12-15 14:29:43 -08001416 item = configfs_get_config_item(dentry);
1417
1418 /* Drop reference from above, item already holds one. */
1419 config_item_put(parent_item);
1420
1421 if (item->ci_type)
Joel Becker70526b62008-06-17 15:34:32 -07001422 dead_item_owner = item->ci_type->ct_owner;
Joel Becker7063fbf2005-12-15 14:29:43 -08001423
1424 if (sd->s_type & CONFIGFS_USET_DIR) {
1425 configfs_detach_group(item);
1426
Joel Beckere6bd07a2007-07-06 23:33:17 -07001427 mutex_lock(&subsys->su_mutex);
Joel Becker299894c2006-10-06 17:33:23 -07001428 client_disconnect_notify(parent_item, item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001429 unlink_group(to_config_group(item));
1430 } else {
1431 configfs_detach_item(item);
1432
Joel Beckere6bd07a2007-07-06 23:33:17 -07001433 mutex_lock(&subsys->su_mutex);
Joel Becker299894c2006-10-06 17:33:23 -07001434 client_disconnect_notify(parent_item, item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001435 unlink_obj(item);
1436 }
1437
1438 client_drop_item(parent_item, item);
Joel Beckere6bd07a2007-07-06 23:33:17 -07001439 mutex_unlock(&subsys->su_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001440
1441 /* Drop our reference from above */
1442 config_item_put(item);
1443
Joel Becker70526b62008-06-17 15:34:32 -07001444 module_put(dead_item_owner);
1445 module_put(subsys_owner);
Joel Becker7063fbf2005-12-15 14:29:43 -08001446
1447 return 0;
1448}
1449
Arjan van de Ven754661f2007-02-12 00:55:38 -08001450const struct inode_operations configfs_dir_inode_operations = {
Joel Becker7063fbf2005-12-15 14:29:43 -08001451 .mkdir = configfs_mkdir,
1452 .rmdir = configfs_rmdir,
1453 .symlink = configfs_symlink,
1454 .unlink = configfs_unlink,
1455 .lookup = configfs_lookup,
Joel Becker3d0f89b2006-01-25 13:31:07 -08001456 .setattr = configfs_setattr,
Joel Becker7063fbf2005-12-15 14:29:43 -08001457};
1458
1459#if 0
1460int configfs_rename_dir(struct config_item * item, const char *new_name)
1461{
1462 int error = 0;
1463 struct dentry * new_dentry, * parent;
1464
1465 if (!strcmp(config_item_name(item), new_name))
1466 return -EINVAL;
1467
1468 if (!item->parent)
1469 return -EINVAL;
1470
1471 down_write(&configfs_rename_sem);
1472 parent = item->parent->dentry;
1473
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001474 mutex_lock(&parent->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001475
1476 new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
1477 if (!IS_ERR(new_dentry)) {
Joel Beckere7515d02006-03-10 11:42:30 -08001478 if (!new_dentry->d_inode) {
Joel Becker7063fbf2005-12-15 14:29:43 -08001479 error = config_item_set_name(item, "%s", new_name);
1480 if (!error) {
1481 d_add(new_dentry, NULL);
1482 d_move(item->dentry, new_dentry);
1483 }
1484 else
1485 d_delete(new_dentry);
1486 } else
1487 error = -EEXIST;
1488 dput(new_dentry);
1489 }
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001490 mutex_unlock(&parent->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001491 up_write(&configfs_rename_sem);
1492
1493 return error;
1494}
1495#endif
1496
1497static int configfs_dir_open(struct inode *inode, struct file *file)
1498{
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001499 struct dentry * dentry = file->f_path.dentry;
Joel Becker7063fbf2005-12-15 14:29:43 -08001500 struct configfs_dirent * parent_sd = dentry->d_fsdata;
Louis Rilling2a109f22008-07-04 16:56:05 +02001501 int err;
Joel Becker7063fbf2005-12-15 14:29:43 -08001502
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001503 mutex_lock(&dentry->d_inode->i_mutex);
Louis Rilling2a109f22008-07-04 16:56:05 +02001504 /*
1505 * Fake invisibility if dir belongs to a group/default groups hierarchy
1506 * being attached
1507 */
1508 err = -ENOENT;
1509 if (configfs_dirent_is_ready(parent_sd)) {
Louis Rilling420118c2009-01-28 19:18:33 +01001510 file->private_data = configfs_new_dirent(parent_sd, NULL, 0);
Louis Rilling2a109f22008-07-04 16:56:05 +02001511 if (IS_ERR(file->private_data))
1512 err = PTR_ERR(file->private_data);
1513 else
1514 err = 0;
1515 }
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001516 mutex_unlock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001517
Louis Rilling2a109f22008-07-04 16:56:05 +02001518 return err;
Joel Becker7063fbf2005-12-15 14:29:43 -08001519}
1520
1521static int configfs_dir_close(struct inode *inode, struct file *file)
1522{
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001523 struct dentry * dentry = file->f_path.dentry;
Joel Becker7063fbf2005-12-15 14:29:43 -08001524 struct configfs_dirent * cursor = file->private_data;
1525
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001526 mutex_lock(&dentry->d_inode->i_mutex);
Louis Rilling6f610762008-06-16 19:00:58 +02001527 spin_lock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -08001528 list_del_init(&cursor->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +02001529 spin_unlock(&configfs_dirent_lock);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001530 mutex_unlock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001531
1532 release_configfs_dirent(cursor);
1533
1534 return 0;
1535}
1536
1537/* Relationship between s_mode and the DT_xxx types */
1538static inline unsigned char dt_type(struct configfs_dirent *sd)
1539{
1540 return (sd->s_mode >> 12) & 15;
1541}
1542
1543static int configfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
1544{
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001545 struct dentry *dentry = filp->f_path.dentry;
Joel Becker7063fbf2005-12-15 14:29:43 -08001546 struct configfs_dirent * parent_sd = dentry->d_fsdata;
1547 struct configfs_dirent *cursor = filp->private_data;
1548 struct list_head *p, *q = &cursor->s_sibling;
1549 ino_t ino;
1550 int i = filp->f_pos;
1551
1552 switch (i) {
1553 case 0:
1554 ino = dentry->d_inode->i_ino;
1555 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
1556 break;
1557 filp->f_pos++;
1558 i++;
1559 /* fallthrough */
1560 case 1:
1561 ino = parent_ino(dentry);
1562 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
1563 break;
1564 filp->f_pos++;
1565 i++;
1566 /* fallthrough */
1567 default:
1568 if (filp->f_pos == 2) {
Louis Rilling6f610762008-06-16 19:00:58 +02001569 spin_lock(&configfs_dirent_lock);
Akinobu Mitaf1166292006-06-26 00:24:46 -07001570 list_move(q, &parent_sd->s_children);
Louis Rilling6f610762008-06-16 19:00:58 +02001571 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -08001572 }
1573 for (p=q->next; p!= &parent_sd->s_children; p=p->next) {
1574 struct configfs_dirent *next;
1575 const char * name;
1576 int len;
1577
1578 next = list_entry(p, struct configfs_dirent,
1579 s_sibling);
1580 if (!next->s_element)
1581 continue;
1582
1583 name = configfs_get_name(next);
1584 len = strlen(name);
1585 if (next->s_dentry)
1586 ino = next->s_dentry->d_inode->i_ino;
1587 else
1588 ino = iunique(configfs_sb, 2);
1589
1590 if (filldir(dirent, name, len, filp->f_pos, ino,
1591 dt_type(next)) < 0)
1592 return 0;
1593
Louis Rilling6f610762008-06-16 19:00:58 +02001594 spin_lock(&configfs_dirent_lock);
Akinobu Mitaf1166292006-06-26 00:24:46 -07001595 list_move(q, p);
Louis Rilling6f610762008-06-16 19:00:58 +02001596 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -08001597 p = q;
1598 filp->f_pos++;
1599 }
1600 }
1601 return 0;
1602}
1603
1604static loff_t configfs_dir_lseek(struct file * file, loff_t offset, int origin)
1605{
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001606 struct dentry * dentry = file->f_path.dentry;
Joel Becker7063fbf2005-12-15 14:29:43 -08001607
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001608 mutex_lock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001609 switch (origin) {
1610 case 1:
1611 offset += file->f_pos;
1612 case 0:
1613 if (offset >= 0)
1614 break;
1615 default:
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001616 mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001617 return -EINVAL;
1618 }
1619 if (offset != file->f_pos) {
1620 file->f_pos = offset;
1621 if (file->f_pos >= 2) {
1622 struct configfs_dirent *sd = dentry->d_fsdata;
1623 struct configfs_dirent *cursor = file->private_data;
1624 struct list_head *p;
1625 loff_t n = file->f_pos - 2;
1626
Louis Rilling6f610762008-06-16 19:00:58 +02001627 spin_lock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -08001628 list_del(&cursor->s_sibling);
1629 p = sd->s_children.next;
1630 while (n && p != &sd->s_children) {
1631 struct configfs_dirent *next;
1632 next = list_entry(p, struct configfs_dirent,
1633 s_sibling);
1634 if (next->s_element)
1635 n--;
1636 p = p->next;
1637 }
1638 list_add_tail(&cursor->s_sibling, p);
Louis Rilling6f610762008-06-16 19:00:58 +02001639 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -08001640 }
1641 }
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001642 mutex_unlock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001643 return offset;
1644}
1645
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -08001646const struct file_operations configfs_dir_operations = {
Joel Becker7063fbf2005-12-15 14:29:43 -08001647 .open = configfs_dir_open,
1648 .release = configfs_dir_close,
1649 .llseek = configfs_dir_lseek,
1650 .read = generic_read_dir,
1651 .readdir = configfs_readdir,
1652};
1653
1654int configfs_register_subsystem(struct configfs_subsystem *subsys)
1655{
1656 int err;
1657 struct config_group *group = &subsys->su_group;
1658 struct qstr name;
1659 struct dentry *dentry;
1660 struct configfs_dirent *sd;
1661
1662 err = configfs_pin_fs();
1663 if (err)
1664 return err;
1665
1666 if (!group->cg_item.ci_name)
1667 group->cg_item.ci_name = group->cg_item.ci_namebuf;
1668
1669 sd = configfs_sb->s_root->d_fsdata;
1670 link_group(to_config_group(sd->s_element), group);
1671
Joonwoo Parkba611ed2007-12-26 12:09:57 +09001672 mutex_lock_nested(&configfs_sb->s_root->d_inode->i_mutex,
1673 I_MUTEX_PARENT);
Joel Becker7063fbf2005-12-15 14:29:43 -08001674
1675 name.name = group->cg_item.ci_name;
1676 name.len = strlen(name.name);
1677 name.hash = full_name_hash(name.name, name.len);
1678
1679 err = -ENOMEM;
1680 dentry = d_alloc(configfs_sb->s_root, &name);
Joel Beckerafdf04e2007-03-05 15:49:49 -08001681 if (dentry) {
1682 d_add(dentry, NULL);
Joel Becker7063fbf2005-12-15 14:29:43 -08001683
Joel Beckerafdf04e2007-03-05 15:49:49 -08001684 err = configfs_attach_group(sd->s_element, &group->cg_item,
1685 dentry);
1686 if (err) {
1687 d_delete(dentry);
1688 dput(dentry);
Louis Rilling2a109f22008-07-04 16:56:05 +02001689 } else {
1690 spin_lock(&configfs_dirent_lock);
1691 configfs_dir_set_ready(dentry->d_fsdata);
1692 spin_unlock(&configfs_dirent_lock);
Joel Beckerafdf04e2007-03-05 15:49:49 -08001693 }
1694 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001695
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001696 mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001697
Joel Beckerafdf04e2007-03-05 15:49:49 -08001698 if (err) {
1699 unlink_group(group);
1700 configfs_release_fs();
Joel Becker7063fbf2005-12-15 14:29:43 -08001701 }
1702
1703 return err;
1704}
1705
1706void configfs_unregister_subsystem(struct configfs_subsystem *subsys)
1707{
1708 struct config_group *group = &subsys->su_group;
1709 struct dentry *dentry = group->cg_item.ci_dentry;
1710
1711 if (dentry->d_parent != configfs_sb->s_root) {
1712 printk(KERN_ERR "configfs: Tried to unregister non-subsystem!\n");
1713 return;
1714 }
1715
Mark Fasheh55ed1602006-10-20 14:55:54 -07001716 mutex_lock_nested(&configfs_sb->s_root->d_inode->i_mutex,
1717 I_MUTEX_PARENT);
1718 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD);
Louis Rilling9a73d782008-06-20 14:09:22 +02001719 mutex_lock(&configfs_symlink_mutex);
Louis Rillingb3e76af2008-06-16 19:01:01 +02001720 spin_lock(&configfs_dirent_lock);
Louis Rilling6d8344b2008-06-16 19:01:02 +02001721 if (configfs_detach_prep(dentry, NULL)) {
Joel Becker7063fbf2005-12-15 14:29:43 -08001722 printk(KERN_ERR "configfs: Tried to unregister non-empty subsystem!\n");
1723 }
Louis Rillingb3e76af2008-06-16 19:01:01 +02001724 spin_unlock(&configfs_dirent_lock);
Louis Rilling9a73d782008-06-20 14:09:22 +02001725 mutex_unlock(&configfs_symlink_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001726 configfs_detach_group(&group->cg_item);
1727 dentry->d_inode->i_flags |= S_DEAD;
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001728 mutex_unlock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001729
1730 d_delete(dentry);
1731
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001732 mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001733
1734 dput(dentry);
1735
1736 unlink_group(group);
1737 configfs_release_fs();
1738}
1739
1740EXPORT_SYMBOL(configfs_register_subsystem);
1741EXPORT_SYMBOL(configfs_unregister_subsystem);