blob: 90ff3cb10de3123d1ca9095d511552eccb7188fe [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 */
Nick Pigginfe15ce42011-01-07 17:49:23 +110070static int configfs_d_delete(const struct dentry *dentry)
Joel Becker7063fbf2005-12-15 14:29:43 -080071{
72 return 1;
73}
74
Al Virod463a0c2011-01-12 16:41:05 -050075const 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;
Nick Pigginfbc8d4c02011-01-07 17:49:21 +1100235 if (dentry)
Joel Becker7063fbf2005-12-15 14:29:43 -0800236 dentry->d_fsdata = configfs_get(sd);
Joel Becker7063fbf2005-12-15 14:29:43 -0800237
238 return 0;
239}
240
241static int init_dir(struct inode * inode)
242{
243 inode->i_op = &configfs_dir_inode_operations;
244 inode->i_fop = &configfs_dir_operations;
245
246 /* directory inodes start off with i_nlink == 2 (for "." entry) */
Dave Hansend8c76e62006-09-30 23:29:04 -0700247 inc_nlink(inode);
Joel Becker7063fbf2005-12-15 14:29:43 -0800248 return 0;
249}
250
Dave Hansence8d2cd2007-10-16 23:31:13 -0700251static int configfs_init_file(struct inode * inode)
Joel Becker7063fbf2005-12-15 14:29:43 -0800252{
253 inode->i_size = PAGE_SIZE;
254 inode->i_fop = &configfs_file_operations;
255 return 0;
256}
257
258static int init_symlink(struct inode * inode)
259{
260 inode->i_op = &configfs_symlink_inode_operations;
261 return 0;
262}
263
264static int create_dir(struct config_item * k, struct dentry * p,
265 struct dentry * d)
266{
267 int error;
268 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
269
Joel Beckerb4c98f62006-09-13 11:01:19 -0700270 error = configfs_dirent_exists(p->d_fsdata, d->d_name.name);
271 if (!error)
272 error = configfs_make_dirent(p->d_fsdata, d, k, mode,
Louis Rilling2a109f22008-07-04 16:56:05 +0200273 CONFIGFS_DIR | CONFIGFS_USET_CREATING);
Joel Becker7063fbf2005-12-15 14:29:43 -0800274 if (!error) {
Louis Rillinge74cc062009-01-28 19:18:32 +0100275 configfs_set_dir_dirent_depth(p->d_fsdata, d->d_fsdata);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800276 error = configfs_create(d, mode, init_dir);
Joel Becker7063fbf2005-12-15 14:29:43 -0800277 if (!error) {
Dave Hansend8c76e62006-09-30 23:29:04 -0700278 inc_nlink(p->d_inode);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800279 } else {
280 struct configfs_dirent *sd = d->d_fsdata;
281 if (sd) {
Louis Rilling6f610762008-06-16 19:00:58 +0200282 spin_lock(&configfs_dirent_lock);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800283 list_del_init(&sd->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +0200284 spin_unlock(&configfs_dirent_lock);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800285 configfs_put(sd);
286 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800287 }
288 }
289 return error;
290}
291
292
293/**
294 * configfs_create_dir - create a directory for an config_item.
295 * @item: config_itemwe're creating directory for.
296 * @dentry: config_item's dentry.
Louis Rilling2a109f22008-07-04 16:56:05 +0200297 *
298 * Note: user-created entries won't be allowed under this new directory
299 * until it is validated by configfs_dir_set_ready()
Joel Becker7063fbf2005-12-15 14:29:43 -0800300 */
301
302static int configfs_create_dir(struct config_item * item, struct dentry *dentry)
303{
304 struct dentry * parent;
305 int error = 0;
306
307 BUG_ON(!item);
308
309 if (item->ci_parent)
310 parent = item->ci_parent->ci_dentry;
311 else if (configfs_mount && configfs_mount->mnt_sb)
312 parent = configfs_mount->mnt_sb->s_root;
313 else
314 return -EFAULT;
315
316 error = create_dir(item,parent,dentry);
317 if (!error)
318 item->ci_dentry = dentry;
319 return error;
320}
321
Louis Rilling2a109f22008-07-04 16:56:05 +0200322/*
323 * Allow userspace to create new entries under a new directory created with
324 * configfs_create_dir(), and under all of its chidlren directories recursively.
325 * @sd configfs_dirent of the new directory to validate
326 *
327 * Caller must hold configfs_dirent_lock.
328 */
329static void configfs_dir_set_ready(struct configfs_dirent *sd)
330{
331 struct configfs_dirent *child_sd;
332
333 sd->s_type &= ~CONFIGFS_USET_CREATING;
334 list_for_each_entry(child_sd, &sd->s_children, s_sibling)
335 if (child_sd->s_type & CONFIGFS_USET_CREATING)
336 configfs_dir_set_ready(child_sd);
337}
338
339/*
340 * Check that a directory does not belong to a directory hierarchy being
341 * attached and not validated yet.
342 * @sd configfs_dirent of the directory to check
343 *
344 * @return non-zero iff the directory was validated
345 *
346 * Note: takes configfs_dirent_lock, so the result may change from false to true
347 * in two consecutive calls, but never from true to false.
348 */
349int configfs_dirent_is_ready(struct configfs_dirent *sd)
350{
351 int ret;
352
353 spin_lock(&configfs_dirent_lock);
354 ret = !(sd->s_type & CONFIGFS_USET_CREATING);
355 spin_unlock(&configfs_dirent_lock);
356
357 return ret;
358}
359
Joel Becker7063fbf2005-12-15 14:29:43 -0800360int configfs_create_link(struct configfs_symlink *sl,
361 struct dentry *parent,
362 struct dentry *dentry)
363{
364 int err = 0;
365 umode_t mode = S_IFLNK | S_IRWXUGO;
366
Joel Becker3d0f89b2006-01-25 13:31:07 -0800367 err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode,
368 CONFIGFS_ITEM_LINK);
Joel Becker7063fbf2005-12-15 14:29:43 -0800369 if (!err) {
Joel Becker3d0f89b2006-01-25 13:31:07 -0800370 err = configfs_create(dentry, mode, init_symlink);
Nick Pigginfbc8d4c02011-01-07 17:49:21 +1100371 if (err) {
Joel Becker3d0f89b2006-01-25 13:31:07 -0800372 struct configfs_dirent *sd = dentry->d_fsdata;
373 if (sd) {
Louis Rilling6f610762008-06-16 19:00:58 +0200374 spin_lock(&configfs_dirent_lock);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800375 list_del_init(&sd->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +0200376 spin_unlock(&configfs_dirent_lock);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800377 configfs_put(sd);
378 }
379 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800380 }
381 return err;
382}
383
384static void remove_dir(struct dentry * d)
385{
386 struct dentry * parent = dget(d->d_parent);
387 struct configfs_dirent * sd;
388
389 sd = d->d_fsdata;
Louis Rilling6f610762008-06-16 19:00:58 +0200390 spin_lock(&configfs_dirent_lock);
Joel Beckere7515d02006-03-10 11:42:30 -0800391 list_del_init(&sd->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +0200392 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800393 configfs_put(sd);
394 if (d->d_inode)
395 simple_rmdir(parent->d_inode,d);
396
Nick Pigginb7ab39f2011-01-07 17:49:32 +1100397 pr_debug(" o %s removing done (%d)\n",d->d_name.name, d->d_count);
Joel Becker7063fbf2005-12-15 14:29:43 -0800398
399 dput(parent);
400}
401
402/**
403 * configfs_remove_dir - remove an config_item's directory.
404 * @item: config_item we're removing.
405 *
406 * The only thing special about this is that we remove any files in
407 * the directory before we remove the directory, and we've inlined
408 * what used to be configfs_rmdir() below, instead of calling separately.
Louis Rilling2e2ce172008-07-04 16:56:06 +0200409 *
410 * Caller holds the mutex of the item's inode
Joel Becker7063fbf2005-12-15 14:29:43 -0800411 */
412
413static void configfs_remove_dir(struct config_item * item)
414{
415 struct dentry * dentry = dget(item->ci_dentry);
416
417 if (!dentry)
418 return;
419
420 remove_dir(dentry);
421 /**
422 * Drop reference from dget() on entrance.
423 */
424 dput(dentry);
425}
426
427
428/* attaches attribute's configfs_dirent to the dentry corresponding to the
429 * attribute file
430 */
431static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry)
432{
433 struct configfs_attribute * attr = sd->s_element;
434 int error;
435
Joel Becker7063fbf2005-12-15 14:29:43 -0800436 dentry->d_fsdata = configfs_get(sd);
437 sd->s_dentry = dentry;
Dave Hansence8d2cd2007-10-16 23:31:13 -0700438 error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG,
439 configfs_init_file);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800440 if (error) {
441 configfs_put(sd);
442 return error;
443 }
444
Joel Becker7063fbf2005-12-15 14:29:43 -0800445 d_rehash(dentry);
446
447 return 0;
448}
449
450static struct dentry * configfs_lookup(struct inode *dir,
451 struct dentry *dentry,
452 struct nameidata *nd)
453{
454 struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
455 struct configfs_dirent * sd;
456 int found = 0;
Louis Rilling2a109f22008-07-04 16:56:05 +0200457 int err;
458
459 /*
460 * Fake invisibility if dir belongs to a group/default groups hierarchy
461 * being attached
462 *
463 * This forbids userspace to read/write attributes of items which may
464 * not complete their initialization, since the dentries of the
465 * attributes won't be instantiated.
466 */
467 err = -ENOENT;
468 if (!configfs_dirent_is_ready(parent_sd))
469 goto out;
Joel Becker7063fbf2005-12-15 14:29:43 -0800470
471 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
472 if (sd->s_type & CONFIGFS_NOT_PINNED) {
473 const unsigned char * name = configfs_get_name(sd);
474
475 if (strcmp(name, dentry->d_name.name))
476 continue;
477
478 found = 1;
479 err = configfs_attach_attr(sd, dentry);
480 break;
481 }
482 }
483
484 if (!found) {
485 /*
486 * If it doesn't exist and it isn't a NOT_PINNED item,
487 * it must be negative.
488 */
Nick Pigginfbc8d4c02011-01-07 17:49:21 +1100489 if (dentry->d_name.len > NAME_MAX)
490 return ERR_PTR(-ENAMETOOLONG);
Nick Pigginfbc8d4c02011-01-07 17:49:21 +1100491 d_add(dentry, NULL);
492 return NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -0800493 }
494
Louis Rilling2a109f22008-07-04 16:56:05 +0200495out:
Joel Becker7063fbf2005-12-15 14:29:43 -0800496 return ERR_PTR(err);
497}
498
499/*
500 * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are
Louis Rillingb3e76af2008-06-16 19:01:01 +0200501 * attributes and are removed by rmdir(). We recurse, setting
502 * CONFIGFS_USET_DROPPING on all children that are candidates for
503 * default detach.
504 * If there is an error, the caller will reset the flags via
505 * configfs_detach_rollback().
Joel Becker7063fbf2005-12-15 14:29:43 -0800506 */
Louis Rilling6d8344b2008-06-16 19:01:02 +0200507static int configfs_detach_prep(struct dentry *dentry, struct mutex **wait_mutex)
Joel Becker7063fbf2005-12-15 14:29:43 -0800508{
509 struct configfs_dirent *parent_sd = dentry->d_fsdata;
510 struct configfs_dirent *sd;
511 int ret;
512
Louis Rilling4768e9b2008-06-23 14:16:17 +0200513 /* Mark that we're trying to drop the group */
514 parent_sd->s_type |= CONFIGFS_USET_DROPPING;
515
Joel Becker7063fbf2005-12-15 14:29:43 -0800516 ret = -EBUSY;
517 if (!list_empty(&parent_sd->s_links))
518 goto out;
519
520 ret = 0;
521 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
Louis Rilling99cefda2008-06-27 13:10:25 +0200522 if (!sd->s_element ||
523 (sd->s_type & CONFIGFS_NOT_PINNED))
Joel Becker7063fbf2005-12-15 14:29:43 -0800524 continue;
525 if (sd->s_type & CONFIGFS_USET_DEFAULT) {
Louis Rilling6d8344b2008-06-16 19:01:02 +0200526 /* Abort if racing with mkdir() */
527 if (sd->s_type & CONFIGFS_USET_IN_MKDIR) {
528 if (wait_mutex)
529 *wait_mutex = &sd->s_dentry->d_inode->i_mutex;
530 return -EAGAIN;
531 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800532
Joel Becker631d1fe2007-06-18 18:06:09 -0700533 /*
534 * Yup, recursive. If there's a problem, blame
535 * deep nesting of default_groups
536 */
Louis Rilling6d8344b2008-06-16 19:01:02 +0200537 ret = configfs_detach_prep(sd->s_dentry, wait_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -0800538 if (!ret)
Joel Beckere7515d02006-03-10 11:42:30 -0800539 continue;
Joel Becker7063fbf2005-12-15 14:29:43 -0800540 } else
541 ret = -ENOTEMPTY;
542
543 break;
544 }
545
546out:
547 return ret;
548}
549
550/*
Louis Rillingb3e76af2008-06-16 19:01:01 +0200551 * Walk the tree, resetting CONFIGFS_USET_DROPPING wherever it was
Joel Becker7063fbf2005-12-15 14:29:43 -0800552 * set.
553 */
554static void configfs_detach_rollback(struct dentry *dentry)
555{
556 struct configfs_dirent *parent_sd = dentry->d_fsdata;
557 struct configfs_dirent *sd;
558
Louis Rilling4768e9b2008-06-23 14:16:17 +0200559 parent_sd->s_type &= ~CONFIGFS_USET_DROPPING;
560
561 list_for_each_entry(sd, &parent_sd->s_children, s_sibling)
562 if (sd->s_type & CONFIGFS_USET_DEFAULT)
Joel Becker7063fbf2005-12-15 14:29:43 -0800563 configfs_detach_rollback(sd->s_dentry);
Joel Becker7063fbf2005-12-15 14:29:43 -0800564}
565
566static void detach_attrs(struct config_item * item)
567{
568 struct dentry * dentry = dget(item->ci_dentry);
569 struct configfs_dirent * parent_sd;
570 struct configfs_dirent * sd, * tmp;
571
572 if (!dentry)
573 return;
574
575 pr_debug("configfs %s: dropping attrs for dir\n",
576 dentry->d_name.name);
577
578 parent_sd = dentry->d_fsdata;
579 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
580 if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED))
581 continue;
Louis Rilling6f610762008-06-16 19:00:58 +0200582 spin_lock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800583 list_del_init(&sd->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +0200584 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800585 configfs_drop_dentry(sd, dentry);
586 configfs_put(sd);
587 }
588
589 /**
590 * Drop reference from dget() on entrance.
591 */
592 dput(dentry);
593}
594
595static int populate_attrs(struct config_item *item)
596{
597 struct config_item_type *t = item->ci_type;
598 struct configfs_attribute *attr;
599 int error = 0;
600 int i;
601
602 if (!t)
603 return -EINVAL;
604 if (t->ct_attrs) {
605 for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) {
606 if ((error = configfs_create_file(item, attr)))
607 break;
608 }
609 }
610
611 if (error)
612 detach_attrs(item);
613
614 return error;
615}
616
617static int configfs_attach_group(struct config_item *parent_item,
618 struct config_item *item,
619 struct dentry *dentry);
620static void configfs_detach_group(struct config_item *item);
621
622static void detach_groups(struct config_group *group)
623{
624 struct dentry * dentry = dget(group->cg_item.ci_dentry);
625 struct dentry *child;
626 struct configfs_dirent *parent_sd;
627 struct configfs_dirent *sd, *tmp;
628
629 if (!dentry)
630 return;
631
632 parent_sd = dentry->d_fsdata;
633 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
634 if (!sd->s_element ||
635 !(sd->s_type & CONFIGFS_USET_DEFAULT))
636 continue;
637
638 child = sd->s_dentry;
639
Louis Rillingb3e76af2008-06-16 19:01:01 +0200640 mutex_lock(&child->d_inode->i_mutex);
641
Joel Becker7063fbf2005-12-15 14:29:43 -0800642 configfs_detach_group(sd->s_element);
643 child->d_inode->i_flags |= S_DEAD;
Al Virod83c49f2010-04-30 17:17:09 -0400644 dont_mount(child);
Joel Becker7063fbf2005-12-15 14:29:43 -0800645
Louis Rillingb3e76af2008-06-16 19:01:01 +0200646 mutex_unlock(&child->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -0800647
648 d_delete(child);
649 dput(child);
650 }
651
652 /**
653 * Drop reference from dget() on entrance.
654 */
655 dput(dentry);
656}
657
658/*
659 * This fakes mkdir(2) on a default_groups[] entry. It
660 * creates a dentry, attachs it, and then does fixup
661 * on the sd->s_type.
662 *
663 * We could, perhaps, tweak our parent's ->mkdir for a minute and
664 * try using vfs_mkdir. Just a thought.
665 */
666static int create_default_group(struct config_group *parent_group,
667 struct config_group *group)
668{
669 int ret;
670 struct qstr name;
671 struct configfs_dirent *sd;
672 /* We trust the caller holds a reference to parent */
673 struct dentry *child, *parent = parent_group->cg_item.ci_dentry;
674
675 if (!group->cg_item.ci_name)
676 group->cg_item.ci_name = group->cg_item.ci_namebuf;
677 name.name = group->cg_item.ci_name;
678 name.len = strlen(name.name);
679 name.hash = full_name_hash(name.name, name.len);
680
681 ret = -ENOMEM;
682 child = d_alloc(parent, &name);
683 if (child) {
684 d_add(child, NULL);
685
686 ret = configfs_attach_group(&parent_group->cg_item,
687 &group->cg_item, child);
688 if (!ret) {
689 sd = child->d_fsdata;
690 sd->s_type |= CONFIGFS_USET_DEFAULT;
691 } else {
692 d_delete(child);
693 dput(child);
694 }
695 }
696
697 return ret;
698}
699
700static int populate_groups(struct config_group *group)
701{
702 struct config_group *new_group;
Joel Becker7063fbf2005-12-15 14:29:43 -0800703 int ret = 0;
704 int i;
705
Eric Sesterhenncbca6922006-03-23 00:36:54 +0100706 if (group->default_groups) {
Joel Becker7063fbf2005-12-15 14:29:43 -0800707 for (i = 0; group->default_groups[i]; i++) {
708 new_group = group->default_groups[i];
709
710 ret = create_default_group(group, new_group);
Louis Rilling2e2ce172008-07-04 16:56:06 +0200711 if (ret) {
712 detach_groups(group);
Joel Becker7063fbf2005-12-15 14:29:43 -0800713 break;
Louis Rilling2e2ce172008-07-04 16:56:06 +0200714 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800715 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800716 }
717
Joel Becker7063fbf2005-12-15 14:29:43 -0800718 return ret;
719}
720
721/*
722 * All of link_obj/unlink_obj/link_group/unlink_group require that
Joel Beckere6bd07a2007-07-06 23:33:17 -0700723 * subsys->su_mutex is held.
Joel Becker7063fbf2005-12-15 14:29:43 -0800724 */
725
726static void unlink_obj(struct config_item *item)
727{
728 struct config_group *group;
729
730 group = item->ci_group;
731 if (group) {
732 list_del_init(&item->ci_entry);
733
734 item->ci_group = NULL;
735 item->ci_parent = NULL;
Joel Beckereed7a0d2006-04-11 21:37:20 -0700736
737 /* Drop the reference for ci_entry */
Joel Becker7063fbf2005-12-15 14:29:43 -0800738 config_item_put(item);
739
Joel Beckereed7a0d2006-04-11 21:37:20 -0700740 /* Drop the reference for ci_parent */
Joel Becker7063fbf2005-12-15 14:29:43 -0800741 config_group_put(group);
742 }
743}
744
745static void link_obj(struct config_item *parent_item, struct config_item *item)
746{
Joel Beckereed7a0d2006-04-11 21:37:20 -0700747 /*
748 * Parent seems redundant with group, but it makes certain
749 * traversals much nicer.
750 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800751 item->ci_parent = parent_item;
Joel Beckereed7a0d2006-04-11 21:37:20 -0700752
753 /*
754 * We hold a reference on the parent for the child's ci_parent
755 * link.
756 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800757 item->ci_group = config_group_get(to_config_group(parent_item));
758 list_add_tail(&item->ci_entry, &item->ci_group->cg_children);
759
Joel Beckereed7a0d2006-04-11 21:37:20 -0700760 /*
761 * We hold a reference on the child for ci_entry on the parent's
762 * cg_children
763 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800764 config_item_get(item);
765}
766
767static void unlink_group(struct config_group *group)
768{
769 int i;
770 struct config_group *new_group;
771
772 if (group->default_groups) {
773 for (i = 0; group->default_groups[i]; i++) {
774 new_group = group->default_groups[i];
775 unlink_group(new_group);
776 }
777 }
778
779 group->cg_subsys = NULL;
780 unlink_obj(&group->cg_item);
781}
782
783static void link_group(struct config_group *parent_group, struct config_group *group)
784{
785 int i;
786 struct config_group *new_group;
787 struct configfs_subsystem *subsys = NULL; /* gcc is a turd */
788
789 link_obj(&parent_group->cg_item, &group->cg_item);
790
791 if (parent_group->cg_subsys)
792 subsys = parent_group->cg_subsys;
793 else if (configfs_is_root(&parent_group->cg_item))
794 subsys = to_configfs_subsystem(group);
795 else
796 BUG();
797 group->cg_subsys = subsys;
798
799 if (group->default_groups) {
800 for (i = 0; group->default_groups[i]; i++) {
801 new_group = group->default_groups[i];
802 link_group(group, new_group);
803 }
804 }
805}
806
807/*
808 * The goal is that configfs_attach_item() (and
809 * configfs_attach_group()) can be called from either the VFS or this
810 * module. That is, they assume that the items have been created,
811 * the dentry allocated, and the dcache is all ready to go.
812 *
813 * If they fail, they must clean up after themselves as if they
814 * had never been called. The caller (VFS or local function) will
815 * handle cleaning up the dcache bits.
816 *
817 * configfs_detach_group() and configfs_detach_item() behave similarly on
818 * the way out. They assume that the proper semaphores are held, they
819 * clean up the configfs items, and they expect their callers will
820 * handle the dcache bits.
821 */
822static int configfs_attach_item(struct config_item *parent_item,
823 struct config_item *item,
824 struct dentry *dentry)
825{
826 int ret;
827
828 ret = configfs_create_dir(item, dentry);
829 if (!ret) {
830 ret = populate_attrs(item);
831 if (ret) {
Louis Rilling2e2ce172008-07-04 16:56:06 +0200832 /*
833 * We are going to remove an inode and its dentry but
834 * the VFS may already have hit and used them. Thus,
835 * we must lock them as rmdir() would.
836 */
837 mutex_lock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -0800838 configfs_remove_dir(item);
Louis Rilling2e2ce172008-07-04 16:56:06 +0200839 dentry->d_inode->i_flags |= S_DEAD;
Al Virod83c49f2010-04-30 17:17:09 -0400840 dont_mount(dentry);
Louis Rilling2e2ce172008-07-04 16:56:06 +0200841 mutex_unlock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -0800842 d_delete(dentry);
843 }
844 }
845
846 return ret;
847}
848
Louis Rilling2e2ce172008-07-04 16:56:06 +0200849/* Caller holds the mutex of the item's inode */
Joel Becker7063fbf2005-12-15 14:29:43 -0800850static void configfs_detach_item(struct config_item *item)
851{
852 detach_attrs(item);
853 configfs_remove_dir(item);
854}
855
856static int configfs_attach_group(struct config_item *parent_item,
857 struct config_item *item,
858 struct dentry *dentry)
859{
860 int ret;
861 struct configfs_dirent *sd;
862
863 ret = configfs_attach_item(parent_item, item, dentry);
864 if (!ret) {
865 sd = dentry->d_fsdata;
866 sd->s_type |= CONFIGFS_USET_DIR;
867
Louis Rilling2e2ce172008-07-04 16:56:06 +0200868 /*
869 * FYI, we're faking mkdir in populate_groups()
870 * We must lock the group's inode to avoid races with the VFS
871 * which can already hit the inode and try to add/remove entries
872 * under it.
873 *
874 * We must also lock the inode to remove it safely in case of
875 * error, as rmdir() would.
876 */
877 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD);
Louis Rillinge74cc062009-01-28 19:18:32 +0100878 configfs_adjust_dir_dirent_depth_before_populate(sd);
Joel Becker7063fbf2005-12-15 14:29:43 -0800879 ret = populate_groups(to_config_group(item));
880 if (ret) {
881 configfs_detach_item(item);
Louis Rilling2e2ce172008-07-04 16:56:06 +0200882 dentry->d_inode->i_flags |= S_DEAD;
Al Virod83c49f2010-04-30 17:17:09 -0400883 dont_mount(dentry);
Joel Becker7063fbf2005-12-15 14:29:43 -0800884 }
Louis Rillinge74cc062009-01-28 19:18:32 +0100885 configfs_adjust_dir_dirent_depth_after_populate(sd);
Louis Rilling2e2ce172008-07-04 16:56:06 +0200886 mutex_unlock(&dentry->d_inode->i_mutex);
887 if (ret)
888 d_delete(dentry);
Joel Becker7063fbf2005-12-15 14:29:43 -0800889 }
890
891 return ret;
892}
893
Louis Rilling2e2ce172008-07-04 16:56:06 +0200894/* Caller holds the mutex of the group's inode */
Joel Becker7063fbf2005-12-15 14:29:43 -0800895static void configfs_detach_group(struct config_item *item)
896{
897 detach_groups(to_config_group(item));
898 configfs_detach_item(item);
899}
900
901/*
Joel Becker299894c2006-10-06 17:33:23 -0700902 * After the item has been detached from the filesystem view, we are
903 * ready to tear it out of the hierarchy. Notify the client before
904 * we do that so they can perform any cleanup that requires
905 * navigating the hierarchy. A client does not need to provide this
906 * callback. The subsystem semaphore MUST be held by the caller, and
907 * references must be valid for both items. It also assumes the
908 * caller has validated ci_type.
909 */
910static void client_disconnect_notify(struct config_item *parent_item,
911 struct config_item *item)
912{
913 struct config_item_type *type;
914
915 type = parent_item->ci_type;
916 BUG_ON(!type);
917
918 if (type->ct_group_ops && type->ct_group_ops->disconnect_notify)
919 type->ct_group_ops->disconnect_notify(to_config_group(parent_item),
920 item);
921}
922
923/*
Joel Becker7063fbf2005-12-15 14:29:43 -0800924 * Drop the initial reference from make_item()/make_group()
925 * This function assumes that reference is held on item
926 * and that item holds a valid reference to the parent. Also, it
927 * assumes the caller has validated ci_type.
928 */
929static void client_drop_item(struct config_item *parent_item,
930 struct config_item *item)
931{
932 struct config_item_type *type;
933
934 type = parent_item->ci_type;
935 BUG_ON(!type);
936
Joel Beckereed7a0d2006-04-11 21:37:20 -0700937 /*
938 * If ->drop_item() exists, it is responsible for the
939 * config_item_put().
940 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800941 if (type->ct_group_ops && type->ct_group_ops->drop_item)
942 type->ct_group_ops->drop_item(to_config_group(parent_item),
Joel Becker299894c2006-10-06 17:33:23 -0700943 item);
Joel Becker7063fbf2005-12-15 14:29:43 -0800944 else
945 config_item_put(item);
946}
947
Joel Becker631d1fe2007-06-18 18:06:09 -0700948#ifdef DEBUG
949static void configfs_dump_one(struct configfs_dirent *sd, int level)
950{
951 printk(KERN_INFO "%*s\"%s\":\n", level, " ", configfs_get_name(sd));
952
953#define type_print(_type) if (sd->s_type & _type) printk(KERN_INFO "%*s %s\n", level, " ", #_type);
954 type_print(CONFIGFS_ROOT);
955 type_print(CONFIGFS_DIR);
956 type_print(CONFIGFS_ITEM_ATTR);
957 type_print(CONFIGFS_ITEM_LINK);
958 type_print(CONFIGFS_USET_DIR);
959 type_print(CONFIGFS_USET_DEFAULT);
960 type_print(CONFIGFS_USET_DROPPING);
961#undef type_print
962}
963
964static int configfs_dump(struct configfs_dirent *sd, int level)
965{
966 struct configfs_dirent *child_sd;
967 int ret = 0;
968
969 configfs_dump_one(sd, level);
970
971 if (!(sd->s_type & (CONFIGFS_DIR|CONFIGFS_ROOT)))
972 return 0;
973
974 list_for_each_entry(child_sd, &sd->s_children, s_sibling) {
975 ret = configfs_dump(child_sd, level + 2);
976 if (ret)
977 break;
978 }
979
980 return ret;
981}
982#endif
983
984
985/*
986 * configfs_depend_item() and configfs_undepend_item()
987 *
988 * WARNING: Do not call these from a configfs callback!
989 *
990 * This describes these functions and their helpers.
991 *
992 * Allow another kernel system to depend on a config_item. If this
993 * happens, the item cannot go away until the dependant can live without
994 * it. The idea is to give client modules as simple an interface as
995 * possible. When a system asks them to depend on an item, they just
996 * call configfs_depend_item(). If the item is live and the client
997 * driver is in good shape, we'll happily do the work for them.
998 *
999 * Why is the locking complex? Because configfs uses the VFS to handle
1000 * all locking, but this function is called outside the normal
1001 * VFS->configfs path. So it must take VFS locks to prevent the
1002 * VFS->configfs stuff (configfs_mkdir(), configfs_rmdir(), etc). This is
1003 * why you can't call these functions underneath configfs callbacks.
1004 *
1005 * Note, btw, that this can be called at *any* time, even when a configfs
1006 * subsystem isn't registered, or when configfs is loading or unloading.
1007 * Just like configfs_register_subsystem(). So we take the same
Louis Rilling420118c2009-01-28 19:18:33 +01001008 * precautions. We pin the filesystem. We lock configfs_dirent_lock.
1009 * If we can find the target item in the
Joel Becker631d1fe2007-06-18 18:06:09 -07001010 * configfs tree, it must be part of the subsystem tree as well, so we
Louis Rilling420118c2009-01-28 19:18:33 +01001011 * do not need the subsystem semaphore. Holding configfs_dirent_lock helps
1012 * locking out mkdir() and rmdir(), who might be racing us.
Joel Becker631d1fe2007-06-18 18:06:09 -07001013 */
1014
1015/*
1016 * configfs_depend_prep()
1017 *
1018 * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are
1019 * attributes. This is similar but not the same to configfs_detach_prep().
1020 * Note that configfs_detach_prep() expects the parent to be locked when it
1021 * is called, but we lock the parent *inside* configfs_depend_prep(). We
1022 * do that so we can unlock it if we find nothing.
1023 *
1024 * Here we do a depth-first search of the dentry hierarchy looking for
Louis Rilling420118c2009-01-28 19:18:33 +01001025 * our object.
1026 * We deliberately ignore items tagged as dropping since they are virtually
1027 * dead, as well as items in the middle of attachment since they virtually
1028 * do not exist yet. This completes the locking out of racing mkdir() and
1029 * rmdir().
1030 * Note: subdirectories in the middle of attachment start with s_type =
1031 * CONFIGFS_DIR|CONFIGFS_USET_CREATING set by create_dir(). When
1032 * CONFIGFS_USET_CREATING is set, we ignore the item. The actual set of
1033 * s_type is in configfs_new_dirent(), which has configfs_dirent_lock.
Joel Becker631d1fe2007-06-18 18:06:09 -07001034 *
Louis Rilling420118c2009-01-28 19:18:33 +01001035 * If the target is not found, -ENOENT is bubbled up.
Joel Becker631d1fe2007-06-18 18:06:09 -07001036 *
1037 * This adds a requirement that all config_items be unique!
1038 *
Louis Rilling420118c2009-01-28 19:18:33 +01001039 * This is recursive. There isn't
Joel Becker631d1fe2007-06-18 18:06:09 -07001040 * much on the stack, though, so folks that need this function - be careful
1041 * about your stack! Patches will be accepted to make it iterative.
1042 */
1043static int configfs_depend_prep(struct dentry *origin,
1044 struct config_item *target)
1045{
1046 struct configfs_dirent *child_sd, *sd = origin->d_fsdata;
1047 int ret = 0;
1048
1049 BUG_ON(!origin || !sd);
1050
Joel Becker631d1fe2007-06-18 18:06:09 -07001051 if (sd->s_element == target) /* Boo-yah */
1052 goto out;
1053
1054 list_for_each_entry(child_sd, &sd->s_children, s_sibling) {
Louis Rilling420118c2009-01-28 19:18:33 +01001055 if ((child_sd->s_type & CONFIGFS_DIR) &&
1056 !(child_sd->s_type & CONFIGFS_USET_DROPPING) &&
1057 !(child_sd->s_type & CONFIGFS_USET_CREATING)) {
Joel Becker631d1fe2007-06-18 18:06:09 -07001058 ret = configfs_depend_prep(child_sd->s_dentry,
1059 target);
1060 if (!ret)
1061 goto out; /* Child path boo-yah */
1062 }
1063 }
1064
1065 /* We looped all our children and didn't find target */
Joel Becker631d1fe2007-06-18 18:06:09 -07001066 ret = -ENOENT;
1067
1068out:
1069 return ret;
1070}
1071
Joel Becker631d1fe2007-06-18 18:06:09 -07001072int configfs_depend_item(struct configfs_subsystem *subsys,
1073 struct config_item *target)
1074{
1075 int ret;
1076 struct configfs_dirent *p, *root_sd, *subsys_sd = NULL;
1077 struct config_item *s_item = &subsys->su_group.cg_item;
1078
1079 /*
1080 * Pin the configfs filesystem. This means we can safely access
1081 * the root of the configfs filesystem.
1082 */
1083 ret = configfs_pin_fs();
1084 if (ret)
1085 return ret;
1086
1087 /*
1088 * Next, lock the root directory. We're going to check that the
1089 * subsystem is really registered, and so we need to lock out
1090 * configfs_[un]register_subsystem().
1091 */
1092 mutex_lock(&configfs_sb->s_root->d_inode->i_mutex);
1093
1094 root_sd = configfs_sb->s_root->d_fsdata;
1095
1096 list_for_each_entry(p, &root_sd->s_children, s_sibling) {
1097 if (p->s_type & CONFIGFS_DIR) {
1098 if (p->s_element == s_item) {
1099 subsys_sd = p;
1100 break;
1101 }
1102 }
1103 }
1104
1105 if (!subsys_sd) {
1106 ret = -ENOENT;
1107 goto out_unlock_fs;
1108 }
1109
1110 /* Ok, now we can trust subsys/s_item */
1111
Louis Rilling420118c2009-01-28 19:18:33 +01001112 spin_lock(&configfs_dirent_lock);
1113 /* Scan the tree, return 0 if found */
Joel Becker631d1fe2007-06-18 18:06:09 -07001114 ret = configfs_depend_prep(subsys_sd->s_dentry, target);
1115 if (ret)
Louis Rilling420118c2009-01-28 19:18:33 +01001116 goto out_unlock_dirent_lock;
Joel Becker631d1fe2007-06-18 18:06:09 -07001117
Louis Rilling420118c2009-01-28 19:18:33 +01001118 /*
1119 * We are sure that the item is not about to be removed by rmdir(), and
1120 * not in the middle of attachment by mkdir().
1121 */
Joel Becker631d1fe2007-06-18 18:06:09 -07001122 p = target->ci_dentry->d_fsdata;
1123 p->s_dependent_count += 1;
1124
Louis Rilling420118c2009-01-28 19:18:33 +01001125out_unlock_dirent_lock:
1126 spin_unlock(&configfs_dirent_lock);
Joel Becker631d1fe2007-06-18 18:06:09 -07001127out_unlock_fs:
1128 mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
1129
1130 /*
1131 * If we succeeded, the fs is pinned via other methods. If not,
1132 * we're done with it anyway. So release_fs() is always right.
1133 */
1134 configfs_release_fs();
1135
1136 return ret;
1137}
1138EXPORT_SYMBOL(configfs_depend_item);
1139
1140/*
1141 * Release the dependent linkage. This is much simpler than
1142 * configfs_depend_item() because we know that that the client driver is
1143 * pinned, thus the subsystem is pinned, and therefore configfs is pinned.
1144 */
1145void configfs_undepend_item(struct configfs_subsystem *subsys,
1146 struct config_item *target)
1147{
1148 struct configfs_dirent *sd;
1149
1150 /*
Louis Rilling420118c2009-01-28 19:18:33 +01001151 * Since we can trust everything is pinned, we just need
1152 * configfs_dirent_lock.
Joel Becker631d1fe2007-06-18 18:06:09 -07001153 */
Louis Rilling420118c2009-01-28 19:18:33 +01001154 spin_lock(&configfs_dirent_lock);
Joel Becker631d1fe2007-06-18 18:06:09 -07001155
1156 sd = target->ci_dentry->d_fsdata;
1157 BUG_ON(sd->s_dependent_count < 1);
1158
1159 sd->s_dependent_count -= 1;
1160
1161 /*
1162 * After this unlock, we cannot trust the item to stay alive!
1163 * DO NOT REFERENCE item after this unlock.
1164 */
Louis Rilling420118c2009-01-28 19:18:33 +01001165 spin_unlock(&configfs_dirent_lock);
Joel Becker631d1fe2007-06-18 18:06:09 -07001166}
1167EXPORT_SYMBOL(configfs_undepend_item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001168
1169static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
1170{
Joel Beckera6795e92008-07-17 15:21:29 -07001171 int ret = 0;
1172 int module_got = 0;
1173 struct config_group *group = NULL;
1174 struct config_item *item = NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -08001175 struct config_item *parent_item;
1176 struct configfs_subsystem *subsys;
1177 struct configfs_dirent *sd;
1178 struct config_item_type *type;
Joel Becker70526b62008-06-17 15:34:32 -07001179 struct module *subsys_owner = NULL, *new_item_owner = NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -08001180 char *name;
1181
Joel Becker84efad12006-03-27 18:46:09 -08001182 if (dentry->d_parent == configfs_sb->s_root) {
1183 ret = -EPERM;
1184 goto out;
1185 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001186
1187 sd = dentry->d_parent->d_fsdata;
Louis Rilling2a109f22008-07-04 16:56:05 +02001188
1189 /*
1190 * Fake invisibility if dir belongs to a group/default groups hierarchy
1191 * being attached
1192 */
1193 if (!configfs_dirent_is_ready(sd)) {
1194 ret = -ENOENT;
1195 goto out;
1196 }
1197
Joel Becker84efad12006-03-27 18:46:09 -08001198 if (!(sd->s_type & CONFIGFS_USET_DIR)) {
1199 ret = -EPERM;
1200 goto out;
1201 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001202
Joel Becker84efad12006-03-27 18:46:09 -08001203 /* Get a working ref for the duration of this function */
Joel Becker7063fbf2005-12-15 14:29:43 -08001204 parent_item = configfs_get_config_item(dentry->d_parent);
1205 type = parent_item->ci_type;
1206 subsys = to_config_group(parent_item)->cg_subsys;
1207 BUG_ON(!subsys);
1208
1209 if (!type || !type->ct_group_ops ||
1210 (!type->ct_group_ops->make_group &&
1211 !type->ct_group_ops->make_item)) {
Joel Becker84efad12006-03-27 18:46:09 -08001212 ret = -EPERM; /* Lack-of-mkdir returns -EPERM */
1213 goto out_put;
Joel Becker7063fbf2005-12-15 14:29:43 -08001214 }
1215
Joel Becker70526b62008-06-17 15:34:32 -07001216 /*
1217 * The subsystem may belong to a different module than the item
1218 * being created. We don't want to safely pin the new item but
1219 * fail to pin the subsystem it sits under.
1220 */
1221 if (!subsys->su_group.cg_item.ci_type) {
1222 ret = -EINVAL;
1223 goto out_put;
1224 }
1225 subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner;
1226 if (!try_module_get(subsys_owner)) {
1227 ret = -EINVAL;
1228 goto out_put;
1229 }
1230
Joel Becker7063fbf2005-12-15 14:29:43 -08001231 name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL);
1232 if (!name) {
Joel Becker84efad12006-03-27 18:46:09 -08001233 ret = -ENOMEM;
Joel Becker70526b62008-06-17 15:34:32 -07001234 goto out_subsys_put;
Joel Becker7063fbf2005-12-15 14:29:43 -08001235 }
Joel Becker84efad12006-03-27 18:46:09 -08001236
Joel Becker7063fbf2005-12-15 14:29:43 -08001237 snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name);
1238
Joel Beckere6bd07a2007-07-06 23:33:17 -07001239 mutex_lock(&subsys->su_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001240 if (type->ct_group_ops->make_group) {
Joel Beckerf89ab862008-07-17 14:53:48 -07001241 group = type->ct_group_ops->make_group(to_config_group(parent_item), name);
Joel Beckera6795e92008-07-17 15:21:29 -07001242 if (!group)
1243 group = ERR_PTR(-ENOMEM);
1244 if (!IS_ERR(group)) {
Joel Becker7063fbf2005-12-15 14:29:43 -08001245 link_group(to_config_group(parent_item), group);
1246 item = &group->cg_item;
Joel Beckera6795e92008-07-17 15:21:29 -07001247 } else
1248 ret = PTR_ERR(group);
Joel Becker7063fbf2005-12-15 14:29:43 -08001249 } else {
Joel Beckerf89ab862008-07-17 14:53:48 -07001250 item = type->ct_group_ops->make_item(to_config_group(parent_item), name);
Joel Beckera6795e92008-07-17 15:21:29 -07001251 if (!item)
1252 item = ERR_PTR(-ENOMEM);
1253 if (!IS_ERR(item))
Joel Becker7063fbf2005-12-15 14:29:43 -08001254 link_obj(parent_item, item);
Joel Beckera6795e92008-07-17 15:21:29 -07001255 else
1256 ret = PTR_ERR(item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001257 }
Joel Beckere6bd07a2007-07-06 23:33:17 -07001258 mutex_unlock(&subsys->su_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001259
1260 kfree(name);
Joel Beckera6795e92008-07-17 15:21:29 -07001261 if (ret) {
Joel Beckereed7a0d2006-04-11 21:37:20 -07001262 /*
Joel Beckerdacdd0e2008-07-17 16:54:19 -07001263 * If ret != 0, then link_obj() was never called.
Joel Beckereed7a0d2006-04-11 21:37:20 -07001264 * There are no extra references to clean up.
1265 */
Joel Becker70526b62008-06-17 15:34:32 -07001266 goto out_subsys_put;
Joel Becker7063fbf2005-12-15 14:29:43 -08001267 }
1268
Joel Beckereed7a0d2006-04-11 21:37:20 -07001269 /*
1270 * link_obj() has been called (via link_group() for groups).
1271 * From here on out, errors must clean that up.
1272 */
1273
Joel Becker7063fbf2005-12-15 14:29:43 -08001274 type = item->ci_type;
Joel Beckereed7a0d2006-04-11 21:37:20 -07001275 if (!type) {
1276 ret = -EINVAL;
1277 goto out_unlink;
1278 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001279
Joel Becker70526b62008-06-17 15:34:32 -07001280 new_item_owner = type->ct_owner;
1281 if (!try_module_get(new_item_owner)) {
Joel Beckereed7a0d2006-04-11 21:37:20 -07001282 ret = -EINVAL;
1283 goto out_unlink;
1284 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001285
Joel Beckereed7a0d2006-04-11 21:37:20 -07001286 /*
1287 * I hate doing it this way, but if there is
1288 * an error, module_put() probably should
1289 * happen after any cleanup.
1290 */
1291 module_got = 1;
1292
Louis Rilling6d8344b2008-06-16 19:01:02 +02001293 /*
1294 * Make racing rmdir() fail if it did not tag parent with
1295 * CONFIGFS_USET_DROPPING
1296 * Note: if CONFIGFS_USET_DROPPING is already set, attach_group() will
1297 * fail and let rmdir() terminate correctly
1298 */
1299 spin_lock(&configfs_dirent_lock);
1300 /* This will make configfs_detach_prep() fail */
1301 sd->s_type |= CONFIGFS_USET_IN_MKDIR;
1302 spin_unlock(&configfs_dirent_lock);
1303
Joel Beckereed7a0d2006-04-11 21:37:20 -07001304 if (group)
1305 ret = configfs_attach_group(parent_item, item, dentry);
1306 else
1307 ret = configfs_attach_item(parent_item, item, dentry);
1308
Louis Rilling6d8344b2008-06-16 19:01:02 +02001309 spin_lock(&configfs_dirent_lock);
1310 sd->s_type &= ~CONFIGFS_USET_IN_MKDIR;
Louis Rilling2a109f22008-07-04 16:56:05 +02001311 if (!ret)
1312 configfs_dir_set_ready(dentry->d_fsdata);
Louis Rilling6d8344b2008-06-16 19:01:02 +02001313 spin_unlock(&configfs_dirent_lock);
1314
Joel Beckereed7a0d2006-04-11 21:37:20 -07001315out_unlink:
1316 if (ret) {
1317 /* Tear down everything we built up */
Joel Beckere6bd07a2007-07-06 23:33:17 -07001318 mutex_lock(&subsys->su_mutex);
Joel Becker299894c2006-10-06 17:33:23 -07001319
1320 client_disconnect_notify(parent_item, item);
Joel Beckereed7a0d2006-04-11 21:37:20 -07001321 if (group)
1322 unlink_group(group);
1323 else
1324 unlink_obj(item);
1325 client_drop_item(parent_item, item);
Joel Becker299894c2006-10-06 17:33:23 -07001326
Joel Beckere6bd07a2007-07-06 23:33:17 -07001327 mutex_unlock(&subsys->su_mutex);
Joel Beckereed7a0d2006-04-11 21:37:20 -07001328
1329 if (module_got)
Joel Becker70526b62008-06-17 15:34:32 -07001330 module_put(new_item_owner);
Joel Becker7063fbf2005-12-15 14:29:43 -08001331 }
1332
Joel Becker70526b62008-06-17 15:34:32 -07001333out_subsys_put:
1334 if (ret)
1335 module_put(subsys_owner);
1336
Joel Becker84efad12006-03-27 18:46:09 -08001337out_put:
1338 /*
Joel Beckereed7a0d2006-04-11 21:37:20 -07001339 * link_obj()/link_group() took a reference from child->parent,
1340 * so the parent is safely pinned. We can drop our working
1341 * reference.
Joel Becker84efad12006-03-27 18:46:09 -08001342 */
1343 config_item_put(parent_item);
1344
1345out:
Joel Becker7063fbf2005-12-15 14:29:43 -08001346 return ret;
1347}
1348
1349static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
1350{
1351 struct config_item *parent_item;
1352 struct config_item *item;
1353 struct configfs_subsystem *subsys;
1354 struct configfs_dirent *sd;
Joel Becker70526b62008-06-17 15:34:32 -07001355 struct module *subsys_owner = NULL, *dead_item_owner = NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -08001356 int ret;
1357
1358 if (dentry->d_parent == configfs_sb->s_root)
1359 return -EPERM;
1360
1361 sd = dentry->d_fsdata;
1362 if (sd->s_type & CONFIGFS_USET_DEFAULT)
1363 return -EPERM;
1364
Joel Becker84efad12006-03-27 18:46:09 -08001365 /* Get a working ref until we have the child */
Joel Becker7063fbf2005-12-15 14:29:43 -08001366 parent_item = configfs_get_config_item(dentry->d_parent);
1367 subsys = to_config_group(parent_item)->cg_subsys;
1368 BUG_ON(!subsys);
1369
1370 if (!parent_item->ci_type) {
1371 config_item_put(parent_item);
1372 return -EINVAL;
1373 }
1374
Joel Becker70526b62008-06-17 15:34:32 -07001375 /* configfs_mkdir() shouldn't have allowed this */
1376 BUG_ON(!subsys->su_group.cg_item.ci_type);
1377 subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner;
1378
Louis Rilling9a73d782008-06-20 14:09:22 +02001379 /*
1380 * Ensure that no racing symlink() will make detach_prep() fail while
1381 * the new link is temporarily attached
1382 */
Louis Rilling6d8344b2008-06-16 19:01:02 +02001383 do {
1384 struct mutex *wait_mutex;
1385
Louis Rillingde6bf182008-08-15 12:37:23 -07001386 mutex_lock(&configfs_symlink_mutex);
1387 spin_lock(&configfs_dirent_lock);
Louis Rilling420118c2009-01-28 19:18:33 +01001388 /*
1389 * Here's where we check for dependents. We're protected by
1390 * configfs_dirent_lock.
1391 * If no dependent, atomically tag the item as dropping.
1392 */
1393 ret = sd->s_dependent_count ? -EBUSY : 0;
1394 if (!ret) {
1395 ret = configfs_detach_prep(dentry, &wait_mutex);
1396 if (ret)
1397 configfs_detach_rollback(dentry);
1398 }
Louis Rillingde6bf182008-08-15 12:37:23 -07001399 spin_unlock(&configfs_dirent_lock);
1400 mutex_unlock(&configfs_symlink_mutex);
1401
1402 if (ret) {
Louis Rilling6d8344b2008-06-16 19:01:02 +02001403 if (ret != -EAGAIN) {
1404 config_item_put(parent_item);
1405 return ret;
1406 }
1407
1408 /* Wait until the racing operation terminates */
1409 mutex_lock(wait_mutex);
1410 mutex_unlock(wait_mutex);
Louis Rilling6d8344b2008-06-16 19:01:02 +02001411 }
1412 } while (ret == -EAGAIN);
Joel Becker7063fbf2005-12-15 14:29:43 -08001413
Joel Becker84efad12006-03-27 18:46:09 -08001414 /* Get a working ref for the duration of this function */
Joel Becker7063fbf2005-12-15 14:29:43 -08001415 item = configfs_get_config_item(dentry);
1416
1417 /* Drop reference from above, item already holds one. */
1418 config_item_put(parent_item);
1419
1420 if (item->ci_type)
Joel Becker70526b62008-06-17 15:34:32 -07001421 dead_item_owner = item->ci_type->ct_owner;
Joel Becker7063fbf2005-12-15 14:29:43 -08001422
1423 if (sd->s_type & CONFIGFS_USET_DIR) {
1424 configfs_detach_group(item);
1425
Joel Beckere6bd07a2007-07-06 23:33:17 -07001426 mutex_lock(&subsys->su_mutex);
Joel Becker299894c2006-10-06 17:33:23 -07001427 client_disconnect_notify(parent_item, item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001428 unlink_group(to_config_group(item));
1429 } else {
1430 configfs_detach_item(item);
1431
Joel Beckere6bd07a2007-07-06 23:33:17 -07001432 mutex_lock(&subsys->su_mutex);
Joel Becker299894c2006-10-06 17:33:23 -07001433 client_disconnect_notify(parent_item, item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001434 unlink_obj(item);
1435 }
1436
1437 client_drop_item(parent_item, item);
Joel Beckere6bd07a2007-07-06 23:33:17 -07001438 mutex_unlock(&subsys->su_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001439
1440 /* Drop our reference from above */
1441 config_item_put(item);
1442
Joel Becker70526b62008-06-17 15:34:32 -07001443 module_put(dead_item_owner);
1444 module_put(subsys_owner);
Joel Becker7063fbf2005-12-15 14:29:43 -08001445
1446 return 0;
1447}
1448
Arjan van de Ven754661f2007-02-12 00:55:38 -08001449const struct inode_operations configfs_dir_inode_operations = {
Joel Becker7063fbf2005-12-15 14:29:43 -08001450 .mkdir = configfs_mkdir,
1451 .rmdir = configfs_rmdir,
1452 .symlink = configfs_symlink,
1453 .unlink = configfs_unlink,
1454 .lookup = configfs_lookup,
Joel Becker3d0f89b2006-01-25 13:31:07 -08001455 .setattr = configfs_setattr,
Joel Becker7063fbf2005-12-15 14:29:43 -08001456};
1457
1458#if 0
1459int configfs_rename_dir(struct config_item * item, const char *new_name)
1460{
1461 int error = 0;
1462 struct dentry * new_dentry, * parent;
1463
1464 if (!strcmp(config_item_name(item), new_name))
1465 return -EINVAL;
1466
1467 if (!item->parent)
1468 return -EINVAL;
1469
1470 down_write(&configfs_rename_sem);
1471 parent = item->parent->dentry;
1472
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001473 mutex_lock(&parent->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001474
1475 new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
1476 if (!IS_ERR(new_dentry)) {
Joel Beckere7515d02006-03-10 11:42:30 -08001477 if (!new_dentry->d_inode) {
Joel Becker7063fbf2005-12-15 14:29:43 -08001478 error = config_item_set_name(item, "%s", new_name);
1479 if (!error) {
1480 d_add(new_dentry, NULL);
1481 d_move(item->dentry, new_dentry);
1482 }
1483 else
1484 d_delete(new_dentry);
1485 } else
1486 error = -EEXIST;
1487 dput(new_dentry);
1488 }
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001489 mutex_unlock(&parent->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001490 up_write(&configfs_rename_sem);
1491
1492 return error;
1493}
1494#endif
1495
1496static int configfs_dir_open(struct inode *inode, struct file *file)
1497{
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001498 struct dentry * dentry = file->f_path.dentry;
Joel Becker7063fbf2005-12-15 14:29:43 -08001499 struct configfs_dirent * parent_sd = dentry->d_fsdata;
Louis Rilling2a109f22008-07-04 16:56:05 +02001500 int err;
Joel Becker7063fbf2005-12-15 14:29:43 -08001501
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001502 mutex_lock(&dentry->d_inode->i_mutex);
Louis Rilling2a109f22008-07-04 16:56:05 +02001503 /*
1504 * Fake invisibility if dir belongs to a group/default groups hierarchy
1505 * being attached
1506 */
1507 err = -ENOENT;
1508 if (configfs_dirent_is_ready(parent_sd)) {
Louis Rilling420118c2009-01-28 19:18:33 +01001509 file->private_data = configfs_new_dirent(parent_sd, NULL, 0);
Louis Rilling2a109f22008-07-04 16:56:05 +02001510 if (IS_ERR(file->private_data))
1511 err = PTR_ERR(file->private_data);
1512 else
1513 err = 0;
1514 }
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001515 mutex_unlock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001516
Louis Rilling2a109f22008-07-04 16:56:05 +02001517 return err;
Joel Becker7063fbf2005-12-15 14:29:43 -08001518}
1519
1520static int configfs_dir_close(struct inode *inode, struct file *file)
1521{
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001522 struct dentry * dentry = file->f_path.dentry;
Joel Becker7063fbf2005-12-15 14:29:43 -08001523 struct configfs_dirent * cursor = file->private_data;
1524
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001525 mutex_lock(&dentry->d_inode->i_mutex);
Louis Rilling6f610762008-06-16 19:00:58 +02001526 spin_lock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -08001527 list_del_init(&cursor->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +02001528 spin_unlock(&configfs_dirent_lock);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001529 mutex_unlock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001530
1531 release_configfs_dirent(cursor);
1532
1533 return 0;
1534}
1535
1536/* Relationship between s_mode and the DT_xxx types */
1537static inline unsigned char dt_type(struct configfs_dirent *sd)
1538{
1539 return (sd->s_mode >> 12) & 15;
1540}
1541
1542static int configfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
1543{
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001544 struct dentry *dentry = filp->f_path.dentry;
Joel Becker7063fbf2005-12-15 14:29:43 -08001545 struct configfs_dirent * parent_sd = dentry->d_fsdata;
1546 struct configfs_dirent *cursor = filp->private_data;
1547 struct list_head *p, *q = &cursor->s_sibling;
1548 ino_t ino;
1549 int i = filp->f_pos;
1550
1551 switch (i) {
1552 case 0:
1553 ino = dentry->d_inode->i_ino;
1554 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
1555 break;
1556 filp->f_pos++;
1557 i++;
1558 /* fallthrough */
1559 case 1:
1560 ino = parent_ino(dentry);
1561 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
1562 break;
1563 filp->f_pos++;
1564 i++;
1565 /* fallthrough */
1566 default:
1567 if (filp->f_pos == 2) {
Louis Rilling6f610762008-06-16 19:00:58 +02001568 spin_lock(&configfs_dirent_lock);
Akinobu Mitaf1166292006-06-26 00:24:46 -07001569 list_move(q, &parent_sd->s_children);
Louis Rilling6f610762008-06-16 19:00:58 +02001570 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -08001571 }
1572 for (p=q->next; p!= &parent_sd->s_children; p=p->next) {
1573 struct configfs_dirent *next;
1574 const char * name;
1575 int len;
1576
1577 next = list_entry(p, struct configfs_dirent,
1578 s_sibling);
1579 if (!next->s_element)
1580 continue;
1581
1582 name = configfs_get_name(next);
1583 len = strlen(name);
1584 if (next->s_dentry)
1585 ino = next->s_dentry->d_inode->i_ino;
1586 else
1587 ino = iunique(configfs_sb, 2);
1588
1589 if (filldir(dirent, name, len, filp->f_pos, ino,
1590 dt_type(next)) < 0)
1591 return 0;
1592
Louis Rilling6f610762008-06-16 19:00:58 +02001593 spin_lock(&configfs_dirent_lock);
Akinobu Mitaf1166292006-06-26 00:24:46 -07001594 list_move(q, p);
Louis Rilling6f610762008-06-16 19:00:58 +02001595 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -08001596 p = q;
1597 filp->f_pos++;
1598 }
1599 }
1600 return 0;
1601}
1602
1603static loff_t configfs_dir_lseek(struct file * file, loff_t offset, int origin)
1604{
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001605 struct dentry * dentry = file->f_path.dentry;
Joel Becker7063fbf2005-12-15 14:29:43 -08001606
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001607 mutex_lock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001608 switch (origin) {
1609 case 1:
1610 offset += file->f_pos;
1611 case 0:
1612 if (offset >= 0)
1613 break;
1614 default:
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001615 mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001616 return -EINVAL;
1617 }
1618 if (offset != file->f_pos) {
1619 file->f_pos = offset;
1620 if (file->f_pos >= 2) {
1621 struct configfs_dirent *sd = dentry->d_fsdata;
1622 struct configfs_dirent *cursor = file->private_data;
1623 struct list_head *p;
1624 loff_t n = file->f_pos - 2;
1625
Louis Rilling6f610762008-06-16 19:00:58 +02001626 spin_lock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -08001627 list_del(&cursor->s_sibling);
1628 p = sd->s_children.next;
1629 while (n && p != &sd->s_children) {
1630 struct configfs_dirent *next;
1631 next = list_entry(p, struct configfs_dirent,
1632 s_sibling);
1633 if (next->s_element)
1634 n--;
1635 p = p->next;
1636 }
1637 list_add_tail(&cursor->s_sibling, p);
Louis Rilling6f610762008-06-16 19:00:58 +02001638 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -08001639 }
1640 }
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001641 mutex_unlock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001642 return offset;
1643}
1644
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -08001645const struct file_operations configfs_dir_operations = {
Joel Becker7063fbf2005-12-15 14:29:43 -08001646 .open = configfs_dir_open,
1647 .release = configfs_dir_close,
1648 .llseek = configfs_dir_lseek,
1649 .read = generic_read_dir,
1650 .readdir = configfs_readdir,
1651};
1652
1653int configfs_register_subsystem(struct configfs_subsystem *subsys)
1654{
1655 int err;
1656 struct config_group *group = &subsys->su_group;
1657 struct qstr name;
1658 struct dentry *dentry;
1659 struct configfs_dirent *sd;
1660
1661 err = configfs_pin_fs();
1662 if (err)
1663 return err;
1664
1665 if (!group->cg_item.ci_name)
1666 group->cg_item.ci_name = group->cg_item.ci_namebuf;
1667
1668 sd = configfs_sb->s_root->d_fsdata;
1669 link_group(to_config_group(sd->s_element), group);
1670
Joonwoo Parkba611ed2007-12-26 12:09:57 +09001671 mutex_lock_nested(&configfs_sb->s_root->d_inode->i_mutex,
1672 I_MUTEX_PARENT);
Joel Becker7063fbf2005-12-15 14:29:43 -08001673
1674 name.name = group->cg_item.ci_name;
1675 name.len = strlen(name.name);
1676 name.hash = full_name_hash(name.name, name.len);
1677
1678 err = -ENOMEM;
1679 dentry = d_alloc(configfs_sb->s_root, &name);
Joel Beckerafdf04e2007-03-05 15:49:49 -08001680 if (dentry) {
1681 d_add(dentry, NULL);
Joel Becker7063fbf2005-12-15 14:29:43 -08001682
Joel Beckerafdf04e2007-03-05 15:49:49 -08001683 err = configfs_attach_group(sd->s_element, &group->cg_item,
1684 dentry);
1685 if (err) {
1686 d_delete(dentry);
1687 dput(dentry);
Louis Rilling2a109f22008-07-04 16:56:05 +02001688 } else {
1689 spin_lock(&configfs_dirent_lock);
1690 configfs_dir_set_ready(dentry->d_fsdata);
1691 spin_unlock(&configfs_dirent_lock);
Joel Beckerafdf04e2007-03-05 15:49:49 -08001692 }
1693 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001694
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001695 mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001696
Joel Beckerafdf04e2007-03-05 15:49:49 -08001697 if (err) {
1698 unlink_group(group);
1699 configfs_release_fs();
Joel Becker7063fbf2005-12-15 14:29:43 -08001700 }
1701
1702 return err;
1703}
1704
1705void configfs_unregister_subsystem(struct configfs_subsystem *subsys)
1706{
1707 struct config_group *group = &subsys->su_group;
1708 struct dentry *dentry = group->cg_item.ci_dentry;
1709
1710 if (dentry->d_parent != configfs_sb->s_root) {
1711 printk(KERN_ERR "configfs: Tried to unregister non-subsystem!\n");
1712 return;
1713 }
1714
Mark Fasheh55ed1602006-10-20 14:55:54 -07001715 mutex_lock_nested(&configfs_sb->s_root->d_inode->i_mutex,
1716 I_MUTEX_PARENT);
1717 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD);
Louis Rilling9a73d782008-06-20 14:09:22 +02001718 mutex_lock(&configfs_symlink_mutex);
Louis Rillingb3e76af2008-06-16 19:01:01 +02001719 spin_lock(&configfs_dirent_lock);
Louis Rilling6d8344b2008-06-16 19:01:02 +02001720 if (configfs_detach_prep(dentry, NULL)) {
Joel Becker7063fbf2005-12-15 14:29:43 -08001721 printk(KERN_ERR "configfs: Tried to unregister non-empty subsystem!\n");
1722 }
Louis Rillingb3e76af2008-06-16 19:01:01 +02001723 spin_unlock(&configfs_dirent_lock);
Louis Rilling9a73d782008-06-20 14:09:22 +02001724 mutex_unlock(&configfs_symlink_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001725 configfs_detach_group(&group->cg_item);
1726 dentry->d_inode->i_flags |= S_DEAD;
Al Virod83c49f2010-04-30 17:17:09 -04001727 dont_mount(dentry);
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);