blob: cf0db005d2f58ab2ed2b42217777f643e6d0d235 [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{
Joel Becker24307aa2011-05-18 04:08:16 -070056 struct configfs_dirent *sd = dentry->d_fsdata;
Joel Becker7063fbf2005-12-15 14:29:43 -080057
58 if (sd) {
Joel Becker24307aa2011-05-18 04:08:16 -070059 /* Coordinate with configfs_readdir */
60 spin_lock(&configfs_dirent_lock);
Junxiao Bi76ae2812013-11-21 14:31:56 -080061 /* Coordinate with configfs_attach_attr where will increase
62 * sd->s_count and update sd->s_dentry to new allocated one.
63 * Only set sd->dentry to null when this dentry is the only
64 * sd owner.
65 * If not do so, configfs_d_iput may run just after
66 * configfs_attach_attr and set sd->s_dentry to null
67 * even it's still in use.
68 */
69 if (atomic_read(&sd->s_count) <= 2)
70 sd->s_dentry = NULL;
71
Joel Becker24307aa2011-05-18 04:08:16 -070072 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -080073 configfs_put(sd);
74 }
75 iput(inode);
76}
77
Al Virod463a0c2011-01-12 16:41:05 -050078const struct dentry_operations configfs_dentry_ops = {
Joel Becker7063fbf2005-12-15 14:29:43 -080079 .d_iput = configfs_d_iput,
Al Virob26d4cd2013-10-25 18:47:37 -040080 .d_delete = always_delete_dentry,
Joel Becker7063fbf2005-12-15 14:29:43 -080081};
82
Louis Rillinge74cc062009-01-28 19:18:32 +010083#ifdef CONFIG_LOCKDEP
84
85/*
86 * Helpers to make lockdep happy with our recursive locking of default groups'
87 * inodes (see configfs_attach_group() and configfs_detach_group()).
88 * We put default groups i_mutexes in separate classes according to their depth
89 * from the youngest non-default group ancestor.
90 *
91 * For a non-default group A having default groups A/B, A/C, and A/C/D, default
92 * groups A/B and A/C will have their inode's mutex in class
93 * default_group_class[0], and default group A/C/D will be in
94 * default_group_class[1].
95 *
96 * The lock classes are declared and assigned in inode.c, according to the
97 * s_depth value.
98 * The s_depth value is initialized to -1, adjusted to >= 0 when attaching
99 * default groups, and reset to -1 when all default groups are attached. During
100 * attachment, if configfs_create() sees s_depth > 0, the lock class of the new
101 * inode's mutex is set to default_group_class[s_depth - 1].
102 */
103
104static void configfs_init_dirent_depth(struct configfs_dirent *sd)
105{
106 sd->s_depth = -1;
107}
108
109static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd,
110 struct configfs_dirent *sd)
111{
112 int parent_depth = parent_sd->s_depth;
113
114 if (parent_depth >= 0)
115 sd->s_depth = parent_depth + 1;
116}
117
118static void
119configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd)
120{
121 /*
122 * item's i_mutex class is already setup, so s_depth is now only
123 * used to set new sub-directories s_depth, which is always done
124 * with item's i_mutex locked.
125 */
126 /*
127 * sd->s_depth == -1 iff we are a non default group.
128 * else (we are a default group) sd->s_depth > 0 (see
129 * create_dir()).
130 */
131 if (sd->s_depth == -1)
132 /*
133 * We are a non default group and we are going to create
134 * default groups.
135 */
136 sd->s_depth = 0;
137}
138
139static void
140configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd)
141{
142 /* We will not create default groups anymore. */
143 sd->s_depth = -1;
144}
145
146#else /* CONFIG_LOCKDEP */
147
148static void configfs_init_dirent_depth(struct configfs_dirent *sd)
149{
150}
151
152static void configfs_set_dir_dirent_depth(struct configfs_dirent *parent_sd,
153 struct configfs_dirent *sd)
154{
155}
156
157static void
158configfs_adjust_dir_dirent_depth_before_populate(struct configfs_dirent *sd)
159{
160}
161
162static void
163configfs_adjust_dir_dirent_depth_after_populate(struct configfs_dirent *sd)
164{
165}
166
167#endif /* CONFIG_LOCKDEP */
168
Joel Becker7063fbf2005-12-15 14:29:43 -0800169/*
170 * Allocates a new configfs_dirent and links it to the parent configfs_dirent
171 */
Louis Rilling420118c2009-01-28 19:18:33 +0100172static struct configfs_dirent *configfs_new_dirent(struct configfs_dirent *parent_sd,
173 void *element, int type)
Joel Becker7063fbf2005-12-15 14:29:43 -0800174{
175 struct configfs_dirent * sd;
176
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800177 sd = kmem_cache_zalloc(configfs_dir_cachep, GFP_KERNEL);
Joel Becker7063fbf2005-12-15 14:29:43 -0800178 if (!sd)
Louis Rilling107ed402008-06-16 19:01:00 +0200179 return ERR_PTR(-ENOMEM);
Joel Becker7063fbf2005-12-15 14:29:43 -0800180
Joel Becker7063fbf2005-12-15 14:29:43 -0800181 atomic_set(&sd->s_count, 1);
182 INIT_LIST_HEAD(&sd->s_links);
183 INIT_LIST_HEAD(&sd->s_children);
Joel Becker7063fbf2005-12-15 14:29:43 -0800184 sd->s_element = element;
Louis Rilling420118c2009-01-28 19:18:33 +0100185 sd->s_type = type;
Louis Rillinge74cc062009-01-28 19:18:32 +0100186 configfs_init_dirent_depth(sd);
Louis Rilling6f610762008-06-16 19:00:58 +0200187 spin_lock(&configfs_dirent_lock);
Louis Rillingb3e76af2008-06-16 19:01:01 +0200188 if (parent_sd->s_type & CONFIGFS_USET_DROPPING) {
189 spin_unlock(&configfs_dirent_lock);
190 kmem_cache_free(configfs_dir_cachep, sd);
191 return ERR_PTR(-ENOENT);
192 }
Louis Rilling6f610762008-06-16 19:00:58 +0200193 list_add(&sd->s_sibling, &parent_sd->s_children);
194 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800195
196 return sd;
197}
198
Joel Beckerb4c98f62006-09-13 11:01:19 -0700199/*
200 *
201 * Return -EEXIST if there is already a configfs element with the same
202 * name for the same parent.
203 *
204 * called with parent inode's i_mutex held
205 */
Adrian Bunk58d206c2006-11-20 03:24:00 +0100206static int configfs_dirent_exists(struct configfs_dirent *parent_sd,
207 const unsigned char *new)
Joel Beckerb4c98f62006-09-13 11:01:19 -0700208{
209 struct configfs_dirent * sd;
210
211 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
212 if (sd->s_element) {
213 const unsigned char *existing = configfs_get_name(sd);
214 if (strcmp(existing, new))
215 continue;
216 else
217 return -EEXIST;
218 }
219 }
220
221 return 0;
222}
223
224
Joel Becker7063fbf2005-12-15 14:29:43 -0800225int configfs_make_dirent(struct configfs_dirent * parent_sd,
226 struct dentry * dentry, void * element,
227 umode_t mode, int type)
228{
229 struct configfs_dirent * sd;
230
Louis Rilling420118c2009-01-28 19:18:33 +0100231 sd = configfs_new_dirent(parent_sd, element, type);
Louis Rilling107ed402008-06-16 19:01:00 +0200232 if (IS_ERR(sd))
233 return PTR_ERR(sd);
Joel Becker7063fbf2005-12-15 14:29:43 -0800234
235 sd->s_mode = mode;
Joel Becker7063fbf2005-12-15 14:29:43 -0800236 sd->s_dentry = dentry;
Nick Pigginfbc8d4c02011-01-07 17:49:21 +1100237 if (dentry)
Joel Becker7063fbf2005-12-15 14:29:43 -0800238 dentry->d_fsdata = configfs_get(sd);
Joel Becker7063fbf2005-12-15 14:29:43 -0800239
240 return 0;
241}
242
Al Viroc88b1e72015-01-29 00:17:57 -0500243static void init_dir(struct inode * inode)
Joel Becker7063fbf2005-12-15 14:29:43 -0800244{
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}
251
Al Viroc88b1e72015-01-29 00:17:57 -0500252static void configfs_init_file(struct inode * inode)
Joel Becker7063fbf2005-12-15 14:29:43 -0800253{
254 inode->i_size = PAGE_SIZE;
255 inode->i_fop = &configfs_file_operations;
Joel Becker7063fbf2005-12-15 14:29:43 -0800256}
257
Al Viroc88b1e72015-01-29 00:17:57 -0500258static void init_symlink(struct inode * inode)
Joel Becker7063fbf2005-12-15 14:29:43 -0800259{
260 inode->i_op = &configfs_symlink_inode_operations;
Joel Becker7063fbf2005-12-15 14:29:43 -0800261}
262
Joel Becker7063fbf2005-12-15 14:29:43 -0800263/**
264 * configfs_create_dir - create a directory for an config_item.
265 * @item: config_itemwe're creating directory for.
266 * @dentry: config_item's dentry.
Louis Rilling2a109f22008-07-04 16:56:05 +0200267 *
268 * Note: user-created entries won't be allowed under this new directory
269 * until it is validated by configfs_dir_set_ready()
Joel Becker7063fbf2005-12-15 14:29:43 -0800270 */
271
Al Viro1cf97d02015-01-29 00:20:49 -0500272static int configfs_create_dir(struct config_item *item, struct dentry *dentry)
Joel Becker7063fbf2005-12-15 14:29:43 -0800273{
Al Viro1cf97d02015-01-29 00:20:49 -0500274 int error;
275 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
276 struct dentry *p = dentry->d_parent;
277
278 BUG_ON(!item);
279
280 error = configfs_dirent_exists(p->d_fsdata, dentry->d_name.name);
281 if (unlikely(error))
282 return error;
283
284 error = configfs_make_dirent(p->d_fsdata, dentry, item, mode,
285 CONFIGFS_DIR | CONFIGFS_USET_CREATING);
286 if (unlikely(error))
287 return error;
288
289 configfs_set_dir_dirent_depth(p->d_fsdata, dentry->d_fsdata);
290 error = configfs_create(dentry, mode, init_dir);
291 if (!error) {
292 inc_nlink(p->d_inode);
Joel Becker7063fbf2005-12-15 14:29:43 -0800293 item->ci_dentry = dentry;
Al Viro1cf97d02015-01-29 00:20:49 -0500294 } else {
295 struct configfs_dirent *sd = dentry->d_fsdata;
296 if (sd) {
297 spin_lock(&configfs_dirent_lock);
298 list_del_init(&sd->s_sibling);
299 spin_unlock(&configfs_dirent_lock);
300 configfs_put(sd);
301 }
302 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800303 return error;
304}
305
Louis Rilling2a109f22008-07-04 16:56:05 +0200306/*
307 * Allow userspace to create new entries under a new directory created with
308 * configfs_create_dir(), and under all of its chidlren directories recursively.
309 * @sd configfs_dirent of the new directory to validate
310 *
311 * Caller must hold configfs_dirent_lock.
312 */
313static void configfs_dir_set_ready(struct configfs_dirent *sd)
314{
315 struct configfs_dirent *child_sd;
316
317 sd->s_type &= ~CONFIGFS_USET_CREATING;
318 list_for_each_entry(child_sd, &sd->s_children, s_sibling)
319 if (child_sd->s_type & CONFIGFS_USET_CREATING)
320 configfs_dir_set_ready(child_sd);
321}
322
323/*
324 * Check that a directory does not belong to a directory hierarchy being
325 * attached and not validated yet.
326 * @sd configfs_dirent of the directory to check
327 *
328 * @return non-zero iff the directory was validated
329 *
330 * Note: takes configfs_dirent_lock, so the result may change from false to true
331 * in two consecutive calls, but never from true to false.
332 */
333int configfs_dirent_is_ready(struct configfs_dirent *sd)
334{
335 int ret;
336
337 spin_lock(&configfs_dirent_lock);
338 ret = !(sd->s_type & CONFIGFS_USET_CREATING);
339 spin_unlock(&configfs_dirent_lock);
340
341 return ret;
342}
343
Joel Becker7063fbf2005-12-15 14:29:43 -0800344int configfs_create_link(struct configfs_symlink *sl,
345 struct dentry *parent,
346 struct dentry *dentry)
347{
348 int err = 0;
349 umode_t mode = S_IFLNK | S_IRWXUGO;
350
Joel Becker3d0f89b2006-01-25 13:31:07 -0800351 err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode,
352 CONFIGFS_ITEM_LINK);
Joel Becker7063fbf2005-12-15 14:29:43 -0800353 if (!err) {
Joel Becker3d0f89b2006-01-25 13:31:07 -0800354 err = configfs_create(dentry, mode, init_symlink);
Nick Pigginfbc8d4c02011-01-07 17:49:21 +1100355 if (err) {
Joel Becker3d0f89b2006-01-25 13:31:07 -0800356 struct configfs_dirent *sd = dentry->d_fsdata;
357 if (sd) {
Louis Rilling6f610762008-06-16 19:00:58 +0200358 spin_lock(&configfs_dirent_lock);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800359 list_del_init(&sd->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +0200360 spin_unlock(&configfs_dirent_lock);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800361 configfs_put(sd);
362 }
363 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800364 }
365 return err;
366}
367
368static void remove_dir(struct dentry * d)
369{
370 struct dentry * parent = dget(d->d_parent);
371 struct configfs_dirent * sd;
372
373 sd = d->d_fsdata;
Louis Rilling6f610762008-06-16 19:00:58 +0200374 spin_lock(&configfs_dirent_lock);
Joel Beckere7515d02006-03-10 11:42:30 -0800375 list_del_init(&sd->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +0200376 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800377 configfs_put(sd);
378 if (d->d_inode)
379 simple_rmdir(parent->d_inode,d);
380
Al Viroa4555892014-10-21 20:11:25 -0400381 pr_debug(" o %pd removing done (%d)\n", d, d_count(d));
Joel Becker7063fbf2005-12-15 14:29:43 -0800382
383 dput(parent);
384}
385
386/**
387 * configfs_remove_dir - remove an config_item's directory.
388 * @item: config_item we're removing.
389 *
390 * The only thing special about this is that we remove any files in
391 * the directory before we remove the directory, and we've inlined
392 * what used to be configfs_rmdir() below, instead of calling separately.
Louis Rilling2e2ce172008-07-04 16:56:06 +0200393 *
394 * Caller holds the mutex of the item's inode
Joel Becker7063fbf2005-12-15 14:29:43 -0800395 */
396
397static void configfs_remove_dir(struct config_item * item)
398{
399 struct dentry * dentry = dget(item->ci_dentry);
400
401 if (!dentry)
402 return;
403
404 remove_dir(dentry);
405 /**
406 * Drop reference from dget() on entrance.
407 */
408 dput(dentry);
409}
410
411
412/* attaches attribute's configfs_dirent to the dentry corresponding to the
413 * attribute file
414 */
415static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry)
416{
417 struct configfs_attribute * attr = sd->s_element;
418 int error;
419
Junxiao Bi76ae2812013-11-21 14:31:56 -0800420 spin_lock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800421 dentry->d_fsdata = configfs_get(sd);
422 sd->s_dentry = dentry;
Junxiao Bi76ae2812013-11-21 14:31:56 -0800423 spin_unlock(&configfs_dirent_lock);
424
Dave Hansence8d2cd2007-10-16 23:31:13 -0700425 error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG,
426 configfs_init_file);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800427 if (error) {
428 configfs_put(sd);
429 return error;
430 }
431
Joel Becker7063fbf2005-12-15 14:29:43 -0800432 d_rehash(dentry);
433
434 return 0;
435}
436
437static struct dentry * configfs_lookup(struct inode *dir,
438 struct dentry *dentry,
Al Viro00cd8dd2012-06-10 17:13:09 -0400439 unsigned int flags)
Joel Becker7063fbf2005-12-15 14:29:43 -0800440{
441 struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
442 struct configfs_dirent * sd;
443 int found = 0;
Louis Rilling2a109f22008-07-04 16:56:05 +0200444 int err;
445
446 /*
447 * Fake invisibility if dir belongs to a group/default groups hierarchy
448 * being attached
449 *
450 * This forbids userspace to read/write attributes of items which may
451 * not complete their initialization, since the dentries of the
452 * attributes won't be instantiated.
453 */
454 err = -ENOENT;
455 if (!configfs_dirent_is_ready(parent_sd))
456 goto out;
Joel Becker7063fbf2005-12-15 14:29:43 -0800457
458 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
459 if (sd->s_type & CONFIGFS_NOT_PINNED) {
460 const unsigned char * name = configfs_get_name(sd);
461
462 if (strcmp(name, dentry->d_name.name))
463 continue;
464
465 found = 1;
466 err = configfs_attach_attr(sd, dentry);
467 break;
468 }
469 }
470
471 if (!found) {
472 /*
473 * If it doesn't exist and it isn't a NOT_PINNED item,
474 * it must be negative.
475 */
Nick Pigginfbc8d4c02011-01-07 17:49:21 +1100476 if (dentry->d_name.len > NAME_MAX)
477 return ERR_PTR(-ENAMETOOLONG);
Nick Pigginfbc8d4c02011-01-07 17:49:21 +1100478 d_add(dentry, NULL);
479 return NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -0800480 }
481
Louis Rilling2a109f22008-07-04 16:56:05 +0200482out:
Joel Becker7063fbf2005-12-15 14:29:43 -0800483 return ERR_PTR(err);
484}
485
486/*
487 * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are
Louis Rillingb3e76af2008-06-16 19:01:01 +0200488 * attributes and are removed by rmdir(). We recurse, setting
489 * CONFIGFS_USET_DROPPING on all children that are candidates for
490 * default detach.
491 * If there is an error, the caller will reset the flags via
492 * configfs_detach_rollback().
Joel Becker7063fbf2005-12-15 14:29:43 -0800493 */
Louis Rilling6d8344b2008-06-16 19:01:02 +0200494static int configfs_detach_prep(struct dentry *dentry, struct mutex **wait_mutex)
Joel Becker7063fbf2005-12-15 14:29:43 -0800495{
496 struct configfs_dirent *parent_sd = dentry->d_fsdata;
497 struct configfs_dirent *sd;
498 int ret;
499
Louis Rilling4768e9b2008-06-23 14:16:17 +0200500 /* Mark that we're trying to drop the group */
501 parent_sd->s_type |= CONFIGFS_USET_DROPPING;
502
Joel Becker7063fbf2005-12-15 14:29:43 -0800503 ret = -EBUSY;
504 if (!list_empty(&parent_sd->s_links))
505 goto out;
506
507 ret = 0;
508 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
Louis Rilling99cefda2008-06-27 13:10:25 +0200509 if (!sd->s_element ||
510 (sd->s_type & CONFIGFS_NOT_PINNED))
Joel Becker7063fbf2005-12-15 14:29:43 -0800511 continue;
512 if (sd->s_type & CONFIGFS_USET_DEFAULT) {
Louis Rilling6d8344b2008-06-16 19:01:02 +0200513 /* Abort if racing with mkdir() */
514 if (sd->s_type & CONFIGFS_USET_IN_MKDIR) {
515 if (wait_mutex)
516 *wait_mutex = &sd->s_dentry->d_inode->i_mutex;
517 return -EAGAIN;
518 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800519
Joel Becker631d1fe2007-06-18 18:06:09 -0700520 /*
521 * Yup, recursive. If there's a problem, blame
522 * deep nesting of default_groups
523 */
Louis Rilling6d8344b2008-06-16 19:01:02 +0200524 ret = configfs_detach_prep(sd->s_dentry, wait_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -0800525 if (!ret)
Joel Beckere7515d02006-03-10 11:42:30 -0800526 continue;
Joel Becker7063fbf2005-12-15 14:29:43 -0800527 } else
528 ret = -ENOTEMPTY;
529
530 break;
531 }
532
533out:
534 return ret;
535}
536
537/*
Louis Rillingb3e76af2008-06-16 19:01:01 +0200538 * Walk the tree, resetting CONFIGFS_USET_DROPPING wherever it was
Joel Becker7063fbf2005-12-15 14:29:43 -0800539 * set.
540 */
541static void configfs_detach_rollback(struct dentry *dentry)
542{
543 struct configfs_dirent *parent_sd = dentry->d_fsdata;
544 struct configfs_dirent *sd;
545
Louis Rilling4768e9b2008-06-23 14:16:17 +0200546 parent_sd->s_type &= ~CONFIGFS_USET_DROPPING;
547
548 list_for_each_entry(sd, &parent_sd->s_children, s_sibling)
549 if (sd->s_type & CONFIGFS_USET_DEFAULT)
Joel Becker7063fbf2005-12-15 14:29:43 -0800550 configfs_detach_rollback(sd->s_dentry);
Joel Becker7063fbf2005-12-15 14:29:43 -0800551}
552
553static void detach_attrs(struct config_item * item)
554{
555 struct dentry * dentry = dget(item->ci_dentry);
556 struct configfs_dirent * parent_sd;
557 struct configfs_dirent * sd, * tmp;
558
559 if (!dentry)
560 return;
561
562 pr_debug("configfs %s: dropping attrs for dir\n",
563 dentry->d_name.name);
564
565 parent_sd = dentry->d_fsdata;
566 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
567 if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED))
568 continue;
Louis Rilling6f610762008-06-16 19:00:58 +0200569 spin_lock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800570 list_del_init(&sd->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +0200571 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800572 configfs_drop_dentry(sd, dentry);
573 configfs_put(sd);
574 }
575
576 /**
577 * Drop reference from dget() on entrance.
578 */
579 dput(dentry);
580}
581
582static int populate_attrs(struct config_item *item)
583{
584 struct config_item_type *t = item->ci_type;
585 struct configfs_attribute *attr;
586 int error = 0;
587 int i;
588
589 if (!t)
590 return -EINVAL;
591 if (t->ct_attrs) {
592 for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) {
593 if ((error = configfs_create_file(item, attr)))
594 break;
595 }
596 }
597
598 if (error)
599 detach_attrs(item);
600
601 return error;
602}
603
604static int configfs_attach_group(struct config_item *parent_item,
605 struct config_item *item,
606 struct dentry *dentry);
607static void configfs_detach_group(struct config_item *item);
608
609static void detach_groups(struct config_group *group)
610{
611 struct dentry * dentry = dget(group->cg_item.ci_dentry);
612 struct dentry *child;
613 struct configfs_dirent *parent_sd;
614 struct configfs_dirent *sd, *tmp;
615
616 if (!dentry)
617 return;
618
619 parent_sd = dentry->d_fsdata;
620 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
621 if (!sd->s_element ||
622 !(sd->s_type & CONFIGFS_USET_DEFAULT))
623 continue;
624
625 child = sd->s_dentry;
626
Louis Rillingb3e76af2008-06-16 19:01:01 +0200627 mutex_lock(&child->d_inode->i_mutex);
628
Joel Becker7063fbf2005-12-15 14:29:43 -0800629 configfs_detach_group(sd->s_element);
630 child->d_inode->i_flags |= S_DEAD;
Al Virod83c49f2010-04-30 17:17:09 -0400631 dont_mount(child);
Joel Becker7063fbf2005-12-15 14:29:43 -0800632
Louis Rillingb3e76af2008-06-16 19:01:01 +0200633 mutex_unlock(&child->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -0800634
635 d_delete(child);
636 dput(child);
637 }
638
639 /**
640 * Drop reference from dget() on entrance.
641 */
642 dput(dentry);
643}
644
645/*
646 * This fakes mkdir(2) on a default_groups[] entry. It
647 * creates a dentry, attachs it, and then does fixup
648 * on the sd->s_type.
649 *
650 * We could, perhaps, tweak our parent's ->mkdir for a minute and
651 * try using vfs_mkdir. Just a thought.
652 */
653static int create_default_group(struct config_group *parent_group,
654 struct config_group *group)
655{
656 int ret;
Joel Becker7063fbf2005-12-15 14:29:43 -0800657 struct configfs_dirent *sd;
658 /* We trust the caller holds a reference to parent */
659 struct dentry *child, *parent = parent_group->cg_item.ci_dentry;
660
661 if (!group->cg_item.ci_name)
662 group->cg_item.ci_name = group->cg_item.ci_namebuf;
Joel Becker7063fbf2005-12-15 14:29:43 -0800663
664 ret = -ENOMEM;
Al Viroec193cf2013-07-14 17:16:52 +0400665 child = d_alloc_name(parent, group->cg_item.ci_name);
Joel Becker7063fbf2005-12-15 14:29:43 -0800666 if (child) {
667 d_add(child, NULL);
668
669 ret = configfs_attach_group(&parent_group->cg_item,
670 &group->cg_item, child);
671 if (!ret) {
672 sd = child->d_fsdata;
673 sd->s_type |= CONFIGFS_USET_DEFAULT;
674 } else {
Joel Beckerdf7f9962011-02-22 01:09:49 -0800675 BUG_ON(child->d_inode);
676 d_drop(child);
Joel Becker7063fbf2005-12-15 14:29:43 -0800677 dput(child);
678 }
679 }
680
681 return ret;
682}
683
684static int populate_groups(struct config_group *group)
685{
686 struct config_group *new_group;
Joel Becker7063fbf2005-12-15 14:29:43 -0800687 int ret = 0;
688 int i;
689
Eric Sesterhenncbca6922006-03-23 00:36:54 +0100690 if (group->default_groups) {
Joel Becker7063fbf2005-12-15 14:29:43 -0800691 for (i = 0; group->default_groups[i]; i++) {
692 new_group = group->default_groups[i];
693
694 ret = create_default_group(group, new_group);
Louis Rilling2e2ce172008-07-04 16:56:06 +0200695 if (ret) {
696 detach_groups(group);
Joel Becker7063fbf2005-12-15 14:29:43 -0800697 break;
Louis Rilling2e2ce172008-07-04 16:56:06 +0200698 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800699 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800700 }
701
Joel Becker7063fbf2005-12-15 14:29:43 -0800702 return ret;
703}
704
705/*
706 * All of link_obj/unlink_obj/link_group/unlink_group require that
Joel Beckere6bd07a2007-07-06 23:33:17 -0700707 * subsys->su_mutex is held.
Joel Becker7063fbf2005-12-15 14:29:43 -0800708 */
709
710static void unlink_obj(struct config_item *item)
711{
712 struct config_group *group;
713
714 group = item->ci_group;
715 if (group) {
716 list_del_init(&item->ci_entry);
717
718 item->ci_group = NULL;
719 item->ci_parent = NULL;
Joel Beckereed7a0d2006-04-11 21:37:20 -0700720
721 /* Drop the reference for ci_entry */
Joel Becker7063fbf2005-12-15 14:29:43 -0800722 config_item_put(item);
723
Joel Beckereed7a0d2006-04-11 21:37:20 -0700724 /* Drop the reference for ci_parent */
Joel Becker7063fbf2005-12-15 14:29:43 -0800725 config_group_put(group);
726 }
727}
728
729static void link_obj(struct config_item *parent_item, struct config_item *item)
730{
Joel Beckereed7a0d2006-04-11 21:37:20 -0700731 /*
732 * Parent seems redundant with group, but it makes certain
733 * traversals much nicer.
734 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800735 item->ci_parent = parent_item;
Joel Beckereed7a0d2006-04-11 21:37:20 -0700736
737 /*
738 * We hold a reference on the parent for the child's ci_parent
739 * link.
740 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800741 item->ci_group = config_group_get(to_config_group(parent_item));
742 list_add_tail(&item->ci_entry, &item->ci_group->cg_children);
743
Joel Beckereed7a0d2006-04-11 21:37:20 -0700744 /*
745 * We hold a reference on the child for ci_entry on the parent's
746 * cg_children
747 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800748 config_item_get(item);
749}
750
751static void unlink_group(struct config_group *group)
752{
753 int i;
754 struct config_group *new_group;
755
756 if (group->default_groups) {
757 for (i = 0; group->default_groups[i]; i++) {
758 new_group = group->default_groups[i];
759 unlink_group(new_group);
760 }
761 }
762
763 group->cg_subsys = NULL;
764 unlink_obj(&group->cg_item);
765}
766
767static void link_group(struct config_group *parent_group, struct config_group *group)
768{
769 int i;
770 struct config_group *new_group;
771 struct configfs_subsystem *subsys = NULL; /* gcc is a turd */
772
773 link_obj(&parent_group->cg_item, &group->cg_item);
774
775 if (parent_group->cg_subsys)
776 subsys = parent_group->cg_subsys;
777 else if (configfs_is_root(&parent_group->cg_item))
778 subsys = to_configfs_subsystem(group);
779 else
780 BUG();
781 group->cg_subsys = subsys;
782
783 if (group->default_groups) {
784 for (i = 0; group->default_groups[i]; i++) {
785 new_group = group->default_groups[i];
786 link_group(group, new_group);
787 }
788 }
789}
790
791/*
792 * The goal is that configfs_attach_item() (and
793 * configfs_attach_group()) can be called from either the VFS or this
794 * module. That is, they assume that the items have been created,
795 * the dentry allocated, and the dcache is all ready to go.
796 *
797 * If they fail, they must clean up after themselves as if they
798 * had never been called. The caller (VFS or local function) will
799 * handle cleaning up the dcache bits.
800 *
801 * configfs_detach_group() and configfs_detach_item() behave similarly on
802 * the way out. They assume that the proper semaphores are held, they
803 * clean up the configfs items, and they expect their callers will
804 * handle the dcache bits.
805 */
806static int configfs_attach_item(struct config_item *parent_item,
807 struct config_item *item,
808 struct dentry *dentry)
809{
810 int ret;
811
812 ret = configfs_create_dir(item, dentry);
813 if (!ret) {
814 ret = populate_attrs(item);
815 if (ret) {
Louis Rilling2e2ce172008-07-04 16:56:06 +0200816 /*
817 * We are going to remove an inode and its dentry but
818 * the VFS may already have hit and used them. Thus,
819 * we must lock them as rmdir() would.
820 */
821 mutex_lock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -0800822 configfs_remove_dir(item);
Louis Rilling2e2ce172008-07-04 16:56:06 +0200823 dentry->d_inode->i_flags |= S_DEAD;
Al Virod83c49f2010-04-30 17:17:09 -0400824 dont_mount(dentry);
Louis Rilling2e2ce172008-07-04 16:56:06 +0200825 mutex_unlock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -0800826 d_delete(dentry);
827 }
828 }
829
830 return ret;
831}
832
Louis Rilling2e2ce172008-07-04 16:56:06 +0200833/* Caller holds the mutex of the item's inode */
Joel Becker7063fbf2005-12-15 14:29:43 -0800834static void configfs_detach_item(struct config_item *item)
835{
836 detach_attrs(item);
837 configfs_remove_dir(item);
838}
839
840static int configfs_attach_group(struct config_item *parent_item,
841 struct config_item *item,
842 struct dentry *dentry)
843{
844 int ret;
845 struct configfs_dirent *sd;
846
847 ret = configfs_attach_item(parent_item, item, dentry);
848 if (!ret) {
849 sd = dentry->d_fsdata;
850 sd->s_type |= CONFIGFS_USET_DIR;
851
Louis Rilling2e2ce172008-07-04 16:56:06 +0200852 /*
853 * FYI, we're faking mkdir in populate_groups()
854 * We must lock the group's inode to avoid races with the VFS
855 * which can already hit the inode and try to add/remove entries
856 * under it.
857 *
858 * We must also lock the inode to remove it safely in case of
859 * error, as rmdir() would.
860 */
861 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD);
Louis Rillinge74cc062009-01-28 19:18:32 +0100862 configfs_adjust_dir_dirent_depth_before_populate(sd);
Joel Becker7063fbf2005-12-15 14:29:43 -0800863 ret = populate_groups(to_config_group(item));
864 if (ret) {
865 configfs_detach_item(item);
Louis Rilling2e2ce172008-07-04 16:56:06 +0200866 dentry->d_inode->i_flags |= S_DEAD;
Al Virod83c49f2010-04-30 17:17:09 -0400867 dont_mount(dentry);
Joel Becker7063fbf2005-12-15 14:29:43 -0800868 }
Louis Rillinge74cc062009-01-28 19:18:32 +0100869 configfs_adjust_dir_dirent_depth_after_populate(sd);
Louis Rilling2e2ce172008-07-04 16:56:06 +0200870 mutex_unlock(&dentry->d_inode->i_mutex);
871 if (ret)
872 d_delete(dentry);
Joel Becker7063fbf2005-12-15 14:29:43 -0800873 }
874
875 return ret;
876}
877
Louis Rilling2e2ce172008-07-04 16:56:06 +0200878/* Caller holds the mutex of the group's inode */
Joel Becker7063fbf2005-12-15 14:29:43 -0800879static void configfs_detach_group(struct config_item *item)
880{
881 detach_groups(to_config_group(item));
882 configfs_detach_item(item);
883}
884
885/*
Joel Becker299894c2006-10-06 17:33:23 -0700886 * After the item has been detached from the filesystem view, we are
887 * ready to tear it out of the hierarchy. Notify the client before
888 * we do that so they can perform any cleanup that requires
889 * navigating the hierarchy. A client does not need to provide this
890 * callback. The subsystem semaphore MUST be held by the caller, and
891 * references must be valid for both items. It also assumes the
892 * caller has validated ci_type.
893 */
894static void client_disconnect_notify(struct config_item *parent_item,
895 struct config_item *item)
896{
897 struct config_item_type *type;
898
899 type = parent_item->ci_type;
900 BUG_ON(!type);
901
902 if (type->ct_group_ops && type->ct_group_ops->disconnect_notify)
903 type->ct_group_ops->disconnect_notify(to_config_group(parent_item),
904 item);
905}
906
907/*
Joel Becker7063fbf2005-12-15 14:29:43 -0800908 * Drop the initial reference from make_item()/make_group()
909 * This function assumes that reference is held on item
910 * and that item holds a valid reference to the parent. Also, it
911 * assumes the caller has validated ci_type.
912 */
913static void client_drop_item(struct config_item *parent_item,
914 struct config_item *item)
915{
916 struct config_item_type *type;
917
918 type = parent_item->ci_type;
919 BUG_ON(!type);
920
Joel Beckereed7a0d2006-04-11 21:37:20 -0700921 /*
922 * If ->drop_item() exists, it is responsible for the
923 * config_item_put().
924 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800925 if (type->ct_group_ops && type->ct_group_ops->drop_item)
926 type->ct_group_ops->drop_item(to_config_group(parent_item),
Joel Becker299894c2006-10-06 17:33:23 -0700927 item);
Joel Becker7063fbf2005-12-15 14:29:43 -0800928 else
929 config_item_put(item);
930}
931
Joel Becker631d1fe2007-06-18 18:06:09 -0700932#ifdef DEBUG
933static void configfs_dump_one(struct configfs_dirent *sd, int level)
934{
Fabian Frederickc6686932014-06-04 16:05:58 -0700935 pr_info("%*s\"%s\":\n", level, " ", configfs_get_name(sd));
Joel Becker631d1fe2007-06-18 18:06:09 -0700936
Fabian Frederickc6686932014-06-04 16:05:58 -0700937#define type_print(_type) if (sd->s_type & _type) pr_info("%*s %s\n", level, " ", #_type);
Joel Becker631d1fe2007-06-18 18:06:09 -0700938 type_print(CONFIGFS_ROOT);
939 type_print(CONFIGFS_DIR);
940 type_print(CONFIGFS_ITEM_ATTR);
941 type_print(CONFIGFS_ITEM_LINK);
942 type_print(CONFIGFS_USET_DIR);
943 type_print(CONFIGFS_USET_DEFAULT);
944 type_print(CONFIGFS_USET_DROPPING);
945#undef type_print
946}
947
948static int configfs_dump(struct configfs_dirent *sd, int level)
949{
950 struct configfs_dirent *child_sd;
951 int ret = 0;
952
953 configfs_dump_one(sd, level);
954
955 if (!(sd->s_type & (CONFIGFS_DIR|CONFIGFS_ROOT)))
956 return 0;
957
958 list_for_each_entry(child_sd, &sd->s_children, s_sibling) {
959 ret = configfs_dump(child_sd, level + 2);
960 if (ret)
961 break;
962 }
963
964 return ret;
965}
966#endif
967
968
969/*
970 * configfs_depend_item() and configfs_undepend_item()
971 *
972 * WARNING: Do not call these from a configfs callback!
973 *
974 * This describes these functions and their helpers.
975 *
976 * Allow another kernel system to depend on a config_item. If this
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300977 * happens, the item cannot go away until the dependent can live without
Joel Becker631d1fe2007-06-18 18:06:09 -0700978 * it. The idea is to give client modules as simple an interface as
979 * possible. When a system asks them to depend on an item, they just
980 * call configfs_depend_item(). If the item is live and the client
981 * driver is in good shape, we'll happily do the work for them.
982 *
983 * Why is the locking complex? Because configfs uses the VFS to handle
984 * all locking, but this function is called outside the normal
985 * VFS->configfs path. So it must take VFS locks to prevent the
986 * VFS->configfs stuff (configfs_mkdir(), configfs_rmdir(), etc). This is
987 * why you can't call these functions underneath configfs callbacks.
988 *
989 * Note, btw, that this can be called at *any* time, even when a configfs
990 * subsystem isn't registered, or when configfs is loading or unloading.
991 * Just like configfs_register_subsystem(). So we take the same
Louis Rilling420118c2009-01-28 19:18:33 +0100992 * precautions. We pin the filesystem. We lock configfs_dirent_lock.
993 * If we can find the target item in the
Joel Becker631d1fe2007-06-18 18:06:09 -0700994 * configfs tree, it must be part of the subsystem tree as well, so we
Louis Rilling420118c2009-01-28 19:18:33 +0100995 * do not need the subsystem semaphore. Holding configfs_dirent_lock helps
996 * locking out mkdir() and rmdir(), who might be racing us.
Joel Becker631d1fe2007-06-18 18:06:09 -0700997 */
998
999/*
1000 * configfs_depend_prep()
1001 *
1002 * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are
1003 * attributes. This is similar but not the same to configfs_detach_prep().
1004 * Note that configfs_detach_prep() expects the parent to be locked when it
1005 * is called, but we lock the parent *inside* configfs_depend_prep(). We
1006 * do that so we can unlock it if we find nothing.
1007 *
1008 * Here we do a depth-first search of the dentry hierarchy looking for
Louis Rilling420118c2009-01-28 19:18:33 +01001009 * our object.
1010 * We deliberately ignore items tagged as dropping since they are virtually
1011 * dead, as well as items in the middle of attachment since they virtually
1012 * do not exist yet. This completes the locking out of racing mkdir() and
1013 * rmdir().
1014 * Note: subdirectories in the middle of attachment start with s_type =
1015 * CONFIGFS_DIR|CONFIGFS_USET_CREATING set by create_dir(). When
1016 * CONFIGFS_USET_CREATING is set, we ignore the item. The actual set of
1017 * s_type is in configfs_new_dirent(), which has configfs_dirent_lock.
Joel Becker631d1fe2007-06-18 18:06:09 -07001018 *
Louis Rilling420118c2009-01-28 19:18:33 +01001019 * If the target is not found, -ENOENT is bubbled up.
Joel Becker631d1fe2007-06-18 18:06:09 -07001020 *
1021 * This adds a requirement that all config_items be unique!
1022 *
Louis Rilling420118c2009-01-28 19:18:33 +01001023 * This is recursive. There isn't
Joel Becker631d1fe2007-06-18 18:06:09 -07001024 * much on the stack, though, so folks that need this function - be careful
1025 * about your stack! Patches will be accepted to make it iterative.
1026 */
1027static int configfs_depend_prep(struct dentry *origin,
1028 struct config_item *target)
1029{
Wei Yongjun49deb4b2013-02-21 16:42:43 -08001030 struct configfs_dirent *child_sd, *sd;
Joel Becker631d1fe2007-06-18 18:06:09 -07001031 int ret = 0;
1032
Wei Yongjun49deb4b2013-02-21 16:42:43 -08001033 BUG_ON(!origin || !origin->d_fsdata);
1034 sd = origin->d_fsdata;
Joel Becker631d1fe2007-06-18 18:06:09 -07001035
Joel Becker631d1fe2007-06-18 18:06:09 -07001036 if (sd->s_element == target) /* Boo-yah */
1037 goto out;
1038
1039 list_for_each_entry(child_sd, &sd->s_children, s_sibling) {
Louis Rilling420118c2009-01-28 19:18:33 +01001040 if ((child_sd->s_type & CONFIGFS_DIR) &&
1041 !(child_sd->s_type & CONFIGFS_USET_DROPPING) &&
1042 !(child_sd->s_type & CONFIGFS_USET_CREATING)) {
Joel Becker631d1fe2007-06-18 18:06:09 -07001043 ret = configfs_depend_prep(child_sd->s_dentry,
1044 target);
1045 if (!ret)
1046 goto out; /* Child path boo-yah */
1047 }
1048 }
1049
1050 /* We looped all our children and didn't find target */
Joel Becker631d1fe2007-06-18 18:06:09 -07001051 ret = -ENOENT;
1052
1053out:
1054 return ret;
1055}
1056
Joel Becker631d1fe2007-06-18 18:06:09 -07001057int configfs_depend_item(struct configfs_subsystem *subsys,
1058 struct config_item *target)
1059{
1060 int ret;
1061 struct configfs_dirent *p, *root_sd, *subsys_sd = NULL;
1062 struct config_item *s_item = &subsys->su_group.cg_item;
Al Virob7c177f2012-03-17 16:24:54 -04001063 struct dentry *root;
Joel Becker631d1fe2007-06-18 18:06:09 -07001064
1065 /*
1066 * Pin the configfs filesystem. This means we can safely access
1067 * the root of the configfs filesystem.
1068 */
Al Viro2a152ad2012-03-17 16:53:29 -04001069 root = configfs_pin_fs();
1070 if (IS_ERR(root))
1071 return PTR_ERR(root);
Joel Becker631d1fe2007-06-18 18:06:09 -07001072
1073 /*
1074 * Next, lock the root directory. We're going to check that the
1075 * subsystem is really registered, and so we need to lock out
1076 * configfs_[un]register_subsystem().
1077 */
Al Virob7c177f2012-03-17 16:24:54 -04001078 mutex_lock(&root->d_inode->i_mutex);
Joel Becker631d1fe2007-06-18 18:06:09 -07001079
Al Virob7c177f2012-03-17 16:24:54 -04001080 root_sd = root->d_fsdata;
Joel Becker631d1fe2007-06-18 18:06:09 -07001081
1082 list_for_each_entry(p, &root_sd->s_children, s_sibling) {
1083 if (p->s_type & CONFIGFS_DIR) {
1084 if (p->s_element == s_item) {
1085 subsys_sd = p;
1086 break;
1087 }
1088 }
1089 }
1090
1091 if (!subsys_sd) {
1092 ret = -ENOENT;
1093 goto out_unlock_fs;
1094 }
1095
1096 /* Ok, now we can trust subsys/s_item */
1097
Louis Rilling420118c2009-01-28 19:18:33 +01001098 spin_lock(&configfs_dirent_lock);
1099 /* Scan the tree, return 0 if found */
Joel Becker631d1fe2007-06-18 18:06:09 -07001100 ret = configfs_depend_prep(subsys_sd->s_dentry, target);
1101 if (ret)
Louis Rilling420118c2009-01-28 19:18:33 +01001102 goto out_unlock_dirent_lock;
Joel Becker631d1fe2007-06-18 18:06:09 -07001103
Louis Rilling420118c2009-01-28 19:18:33 +01001104 /*
1105 * We are sure that the item is not about to be removed by rmdir(), and
1106 * not in the middle of attachment by mkdir().
1107 */
Joel Becker631d1fe2007-06-18 18:06:09 -07001108 p = target->ci_dentry->d_fsdata;
1109 p->s_dependent_count += 1;
1110
Louis Rilling420118c2009-01-28 19:18:33 +01001111out_unlock_dirent_lock:
1112 spin_unlock(&configfs_dirent_lock);
Joel Becker631d1fe2007-06-18 18:06:09 -07001113out_unlock_fs:
Al Virob7c177f2012-03-17 16:24:54 -04001114 mutex_unlock(&root->d_inode->i_mutex);
Joel Becker631d1fe2007-06-18 18:06:09 -07001115
1116 /*
1117 * If we succeeded, the fs is pinned via other methods. If not,
1118 * we're done with it anyway. So release_fs() is always right.
1119 */
1120 configfs_release_fs();
1121
1122 return ret;
1123}
1124EXPORT_SYMBOL(configfs_depend_item);
1125
1126/*
1127 * Release the dependent linkage. This is much simpler than
1128 * configfs_depend_item() because we know that that the client driver is
1129 * pinned, thus the subsystem is pinned, and therefore configfs is pinned.
1130 */
1131void configfs_undepend_item(struct configfs_subsystem *subsys,
1132 struct config_item *target)
1133{
1134 struct configfs_dirent *sd;
1135
1136 /*
Louis Rilling420118c2009-01-28 19:18:33 +01001137 * Since we can trust everything is pinned, we just need
1138 * configfs_dirent_lock.
Joel Becker631d1fe2007-06-18 18:06:09 -07001139 */
Louis Rilling420118c2009-01-28 19:18:33 +01001140 spin_lock(&configfs_dirent_lock);
Joel Becker631d1fe2007-06-18 18:06:09 -07001141
1142 sd = target->ci_dentry->d_fsdata;
1143 BUG_ON(sd->s_dependent_count < 1);
1144
1145 sd->s_dependent_count -= 1;
1146
1147 /*
1148 * After this unlock, we cannot trust the item to stay alive!
1149 * DO NOT REFERENCE item after this unlock.
1150 */
Louis Rilling420118c2009-01-28 19:18:33 +01001151 spin_unlock(&configfs_dirent_lock);
Joel Becker631d1fe2007-06-18 18:06:09 -07001152}
1153EXPORT_SYMBOL(configfs_undepend_item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001154
Al Viro18bb1db2011-07-26 01:41:39 -04001155static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
Joel Becker7063fbf2005-12-15 14:29:43 -08001156{
Joel Beckera6795e92008-07-17 15:21:29 -07001157 int ret = 0;
1158 int module_got = 0;
1159 struct config_group *group = NULL;
1160 struct config_item *item = NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -08001161 struct config_item *parent_item;
1162 struct configfs_subsystem *subsys;
1163 struct configfs_dirent *sd;
1164 struct config_item_type *type;
Joel Becker70526b62008-06-17 15:34:32 -07001165 struct module *subsys_owner = NULL, *new_item_owner = NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -08001166 char *name;
1167
Joel Becker7063fbf2005-12-15 14:29:43 -08001168 sd = dentry->d_parent->d_fsdata;
Louis Rilling2a109f22008-07-04 16:56:05 +02001169
1170 /*
1171 * Fake invisibility if dir belongs to a group/default groups hierarchy
1172 * being attached
1173 */
1174 if (!configfs_dirent_is_ready(sd)) {
1175 ret = -ENOENT;
1176 goto out;
1177 }
1178
Joel Becker84efad12006-03-27 18:46:09 -08001179 if (!(sd->s_type & CONFIGFS_USET_DIR)) {
1180 ret = -EPERM;
1181 goto out;
1182 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001183
Joel Becker84efad12006-03-27 18:46:09 -08001184 /* Get a working ref for the duration of this function */
Joel Becker7063fbf2005-12-15 14:29:43 -08001185 parent_item = configfs_get_config_item(dentry->d_parent);
1186 type = parent_item->ci_type;
1187 subsys = to_config_group(parent_item)->cg_subsys;
1188 BUG_ON(!subsys);
1189
1190 if (!type || !type->ct_group_ops ||
1191 (!type->ct_group_ops->make_group &&
1192 !type->ct_group_ops->make_item)) {
Joel Becker84efad12006-03-27 18:46:09 -08001193 ret = -EPERM; /* Lack-of-mkdir returns -EPERM */
1194 goto out_put;
Joel Becker7063fbf2005-12-15 14:29:43 -08001195 }
1196
Joel Becker70526b62008-06-17 15:34:32 -07001197 /*
1198 * The subsystem may belong to a different module than the item
1199 * being created. We don't want to safely pin the new item but
1200 * fail to pin the subsystem it sits under.
1201 */
1202 if (!subsys->su_group.cg_item.ci_type) {
1203 ret = -EINVAL;
1204 goto out_put;
1205 }
1206 subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner;
1207 if (!try_module_get(subsys_owner)) {
1208 ret = -EINVAL;
1209 goto out_put;
1210 }
1211
Joel Becker7063fbf2005-12-15 14:29:43 -08001212 name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL);
1213 if (!name) {
Joel Becker84efad12006-03-27 18:46:09 -08001214 ret = -ENOMEM;
Joel Becker70526b62008-06-17 15:34:32 -07001215 goto out_subsys_put;
Joel Becker7063fbf2005-12-15 14:29:43 -08001216 }
Joel Becker84efad12006-03-27 18:46:09 -08001217
Joel Becker7063fbf2005-12-15 14:29:43 -08001218 snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name);
1219
Joel Beckere6bd07a2007-07-06 23:33:17 -07001220 mutex_lock(&subsys->su_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001221 if (type->ct_group_ops->make_group) {
Joel Beckerf89ab862008-07-17 14:53:48 -07001222 group = type->ct_group_ops->make_group(to_config_group(parent_item), name);
Joel Beckera6795e92008-07-17 15:21:29 -07001223 if (!group)
1224 group = ERR_PTR(-ENOMEM);
1225 if (!IS_ERR(group)) {
Joel Becker7063fbf2005-12-15 14:29:43 -08001226 link_group(to_config_group(parent_item), group);
1227 item = &group->cg_item;
Joel Beckera6795e92008-07-17 15:21:29 -07001228 } else
1229 ret = PTR_ERR(group);
Joel Becker7063fbf2005-12-15 14:29:43 -08001230 } else {
Joel Beckerf89ab862008-07-17 14:53:48 -07001231 item = type->ct_group_ops->make_item(to_config_group(parent_item), name);
Joel Beckera6795e92008-07-17 15:21:29 -07001232 if (!item)
1233 item = ERR_PTR(-ENOMEM);
1234 if (!IS_ERR(item))
Joel Becker7063fbf2005-12-15 14:29:43 -08001235 link_obj(parent_item, item);
Joel Beckera6795e92008-07-17 15:21:29 -07001236 else
1237 ret = PTR_ERR(item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001238 }
Joel Beckere6bd07a2007-07-06 23:33:17 -07001239 mutex_unlock(&subsys->su_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001240
1241 kfree(name);
Joel Beckera6795e92008-07-17 15:21:29 -07001242 if (ret) {
Joel Beckereed7a0d2006-04-11 21:37:20 -07001243 /*
Joel Beckerdacdd0e2008-07-17 16:54:19 -07001244 * If ret != 0, then link_obj() was never called.
Joel Beckereed7a0d2006-04-11 21:37:20 -07001245 * There are no extra references to clean up.
1246 */
Joel Becker70526b62008-06-17 15:34:32 -07001247 goto out_subsys_put;
Joel Becker7063fbf2005-12-15 14:29:43 -08001248 }
1249
Joel Beckereed7a0d2006-04-11 21:37:20 -07001250 /*
1251 * link_obj() has been called (via link_group() for groups).
1252 * From here on out, errors must clean that up.
1253 */
1254
Joel Becker7063fbf2005-12-15 14:29:43 -08001255 type = item->ci_type;
Joel Beckereed7a0d2006-04-11 21:37:20 -07001256 if (!type) {
1257 ret = -EINVAL;
1258 goto out_unlink;
1259 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001260
Joel Becker70526b62008-06-17 15:34:32 -07001261 new_item_owner = type->ct_owner;
1262 if (!try_module_get(new_item_owner)) {
Joel Beckereed7a0d2006-04-11 21:37:20 -07001263 ret = -EINVAL;
1264 goto out_unlink;
1265 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001266
Joel Beckereed7a0d2006-04-11 21:37:20 -07001267 /*
1268 * I hate doing it this way, but if there is
1269 * an error, module_put() probably should
1270 * happen after any cleanup.
1271 */
1272 module_got = 1;
1273
Louis Rilling6d8344b2008-06-16 19:01:02 +02001274 /*
1275 * Make racing rmdir() fail if it did not tag parent with
1276 * CONFIGFS_USET_DROPPING
1277 * Note: if CONFIGFS_USET_DROPPING is already set, attach_group() will
1278 * fail and let rmdir() terminate correctly
1279 */
1280 spin_lock(&configfs_dirent_lock);
1281 /* This will make configfs_detach_prep() fail */
1282 sd->s_type |= CONFIGFS_USET_IN_MKDIR;
1283 spin_unlock(&configfs_dirent_lock);
1284
Joel Beckereed7a0d2006-04-11 21:37:20 -07001285 if (group)
1286 ret = configfs_attach_group(parent_item, item, dentry);
1287 else
1288 ret = configfs_attach_item(parent_item, item, dentry);
1289
Louis Rilling6d8344b2008-06-16 19:01:02 +02001290 spin_lock(&configfs_dirent_lock);
1291 sd->s_type &= ~CONFIGFS_USET_IN_MKDIR;
Louis Rilling2a109f22008-07-04 16:56:05 +02001292 if (!ret)
1293 configfs_dir_set_ready(dentry->d_fsdata);
Louis Rilling6d8344b2008-06-16 19:01:02 +02001294 spin_unlock(&configfs_dirent_lock);
1295
Joel Beckereed7a0d2006-04-11 21:37:20 -07001296out_unlink:
1297 if (ret) {
1298 /* Tear down everything we built up */
Joel Beckere6bd07a2007-07-06 23:33:17 -07001299 mutex_lock(&subsys->su_mutex);
Joel Becker299894c2006-10-06 17:33:23 -07001300
1301 client_disconnect_notify(parent_item, item);
Joel Beckereed7a0d2006-04-11 21:37:20 -07001302 if (group)
1303 unlink_group(group);
1304 else
1305 unlink_obj(item);
1306 client_drop_item(parent_item, item);
Joel Becker299894c2006-10-06 17:33:23 -07001307
Joel Beckere6bd07a2007-07-06 23:33:17 -07001308 mutex_unlock(&subsys->su_mutex);
Joel Beckereed7a0d2006-04-11 21:37:20 -07001309
1310 if (module_got)
Joel Becker70526b62008-06-17 15:34:32 -07001311 module_put(new_item_owner);
Joel Becker7063fbf2005-12-15 14:29:43 -08001312 }
1313
Joel Becker70526b62008-06-17 15:34:32 -07001314out_subsys_put:
1315 if (ret)
1316 module_put(subsys_owner);
1317
Joel Becker84efad12006-03-27 18:46:09 -08001318out_put:
1319 /*
Joel Beckereed7a0d2006-04-11 21:37:20 -07001320 * link_obj()/link_group() took a reference from child->parent,
1321 * so the parent is safely pinned. We can drop our working
1322 * reference.
Joel Becker84efad12006-03-27 18:46:09 -08001323 */
1324 config_item_put(parent_item);
1325
1326out:
Joel Becker7063fbf2005-12-15 14:29:43 -08001327 return ret;
1328}
1329
1330static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
1331{
1332 struct config_item *parent_item;
1333 struct config_item *item;
1334 struct configfs_subsystem *subsys;
1335 struct configfs_dirent *sd;
Joel Becker70526b62008-06-17 15:34:32 -07001336 struct module *subsys_owner = NULL, *dead_item_owner = NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -08001337 int ret;
1338
Joel Becker7063fbf2005-12-15 14:29:43 -08001339 sd = dentry->d_fsdata;
1340 if (sd->s_type & CONFIGFS_USET_DEFAULT)
1341 return -EPERM;
1342
Joel Becker84efad12006-03-27 18:46:09 -08001343 /* Get a working ref until we have the child */
Joel Becker7063fbf2005-12-15 14:29:43 -08001344 parent_item = configfs_get_config_item(dentry->d_parent);
1345 subsys = to_config_group(parent_item)->cg_subsys;
1346 BUG_ON(!subsys);
1347
1348 if (!parent_item->ci_type) {
1349 config_item_put(parent_item);
1350 return -EINVAL;
1351 }
1352
Joel Becker70526b62008-06-17 15:34:32 -07001353 /* configfs_mkdir() shouldn't have allowed this */
1354 BUG_ON(!subsys->su_group.cg_item.ci_type);
1355 subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner;
1356
Louis Rilling9a73d782008-06-20 14:09:22 +02001357 /*
1358 * Ensure that no racing symlink() will make detach_prep() fail while
1359 * the new link is temporarily attached
1360 */
Louis Rilling6d8344b2008-06-16 19:01:02 +02001361 do {
1362 struct mutex *wait_mutex;
1363
Louis Rillingde6bf182008-08-15 12:37:23 -07001364 mutex_lock(&configfs_symlink_mutex);
1365 spin_lock(&configfs_dirent_lock);
Louis Rilling420118c2009-01-28 19:18:33 +01001366 /*
1367 * Here's where we check for dependents. We're protected by
1368 * configfs_dirent_lock.
1369 * If no dependent, atomically tag the item as dropping.
1370 */
1371 ret = sd->s_dependent_count ? -EBUSY : 0;
1372 if (!ret) {
1373 ret = configfs_detach_prep(dentry, &wait_mutex);
1374 if (ret)
1375 configfs_detach_rollback(dentry);
1376 }
Louis Rillingde6bf182008-08-15 12:37:23 -07001377 spin_unlock(&configfs_dirent_lock);
1378 mutex_unlock(&configfs_symlink_mutex);
1379
1380 if (ret) {
Louis Rilling6d8344b2008-06-16 19:01:02 +02001381 if (ret != -EAGAIN) {
1382 config_item_put(parent_item);
1383 return ret;
1384 }
1385
1386 /* Wait until the racing operation terminates */
1387 mutex_lock(wait_mutex);
1388 mutex_unlock(wait_mutex);
Louis Rilling6d8344b2008-06-16 19:01:02 +02001389 }
1390 } while (ret == -EAGAIN);
Joel Becker7063fbf2005-12-15 14:29:43 -08001391
Joel Becker84efad12006-03-27 18:46:09 -08001392 /* Get a working ref for the duration of this function */
Joel Becker7063fbf2005-12-15 14:29:43 -08001393 item = configfs_get_config_item(dentry);
1394
1395 /* Drop reference from above, item already holds one. */
1396 config_item_put(parent_item);
1397
1398 if (item->ci_type)
Joel Becker70526b62008-06-17 15:34:32 -07001399 dead_item_owner = item->ci_type->ct_owner;
Joel Becker7063fbf2005-12-15 14:29:43 -08001400
1401 if (sd->s_type & CONFIGFS_USET_DIR) {
1402 configfs_detach_group(item);
1403
Joel Beckere6bd07a2007-07-06 23:33:17 -07001404 mutex_lock(&subsys->su_mutex);
Joel Becker299894c2006-10-06 17:33:23 -07001405 client_disconnect_notify(parent_item, item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001406 unlink_group(to_config_group(item));
1407 } else {
1408 configfs_detach_item(item);
1409
Joel Beckere6bd07a2007-07-06 23:33:17 -07001410 mutex_lock(&subsys->su_mutex);
Joel Becker299894c2006-10-06 17:33:23 -07001411 client_disconnect_notify(parent_item, item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001412 unlink_obj(item);
1413 }
1414
1415 client_drop_item(parent_item, item);
Joel Beckere6bd07a2007-07-06 23:33:17 -07001416 mutex_unlock(&subsys->su_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001417
1418 /* Drop our reference from above */
1419 config_item_put(item);
1420
Joel Becker70526b62008-06-17 15:34:32 -07001421 module_put(dead_item_owner);
1422 module_put(subsys_owner);
Joel Becker7063fbf2005-12-15 14:29:43 -08001423
1424 return 0;
1425}
1426
Arjan van de Ven754661f2007-02-12 00:55:38 -08001427const struct inode_operations configfs_dir_inode_operations = {
Joel Becker7063fbf2005-12-15 14:29:43 -08001428 .mkdir = configfs_mkdir,
1429 .rmdir = configfs_rmdir,
1430 .symlink = configfs_symlink,
1431 .unlink = configfs_unlink,
1432 .lookup = configfs_lookup,
Joel Becker3d0f89b2006-01-25 13:31:07 -08001433 .setattr = configfs_setattr,
Joel Becker7063fbf2005-12-15 14:29:43 -08001434};
1435
Al Viro81d44ed12012-03-17 16:13:25 -04001436const struct inode_operations configfs_root_inode_operations = {
1437 .lookup = configfs_lookup,
1438 .setattr = configfs_setattr,
1439};
1440
Joel Becker7063fbf2005-12-15 14:29:43 -08001441#if 0
1442int configfs_rename_dir(struct config_item * item, const char *new_name)
1443{
1444 int error = 0;
1445 struct dentry * new_dentry, * parent;
1446
1447 if (!strcmp(config_item_name(item), new_name))
1448 return -EINVAL;
1449
1450 if (!item->parent)
1451 return -EINVAL;
1452
1453 down_write(&configfs_rename_sem);
1454 parent = item->parent->dentry;
1455
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001456 mutex_lock(&parent->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001457
1458 new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
1459 if (!IS_ERR(new_dentry)) {
Joel Beckere7515d02006-03-10 11:42:30 -08001460 if (!new_dentry->d_inode) {
Joel Becker7063fbf2005-12-15 14:29:43 -08001461 error = config_item_set_name(item, "%s", new_name);
1462 if (!error) {
1463 d_add(new_dentry, NULL);
1464 d_move(item->dentry, new_dentry);
1465 }
1466 else
1467 d_delete(new_dentry);
1468 } else
1469 error = -EEXIST;
1470 dput(new_dentry);
1471 }
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001472 mutex_unlock(&parent->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001473 up_write(&configfs_rename_sem);
1474
1475 return error;
1476}
1477#endif
1478
1479static int configfs_dir_open(struct inode *inode, struct file *file)
1480{
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001481 struct dentry * dentry = file->f_path.dentry;
Joel Becker7063fbf2005-12-15 14:29:43 -08001482 struct configfs_dirent * parent_sd = dentry->d_fsdata;
Louis Rilling2a109f22008-07-04 16:56:05 +02001483 int err;
Joel Becker7063fbf2005-12-15 14:29:43 -08001484
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001485 mutex_lock(&dentry->d_inode->i_mutex);
Louis Rilling2a109f22008-07-04 16:56:05 +02001486 /*
1487 * Fake invisibility if dir belongs to a group/default groups hierarchy
1488 * being attached
1489 */
1490 err = -ENOENT;
1491 if (configfs_dirent_is_ready(parent_sd)) {
Louis Rilling420118c2009-01-28 19:18:33 +01001492 file->private_data = configfs_new_dirent(parent_sd, NULL, 0);
Louis Rilling2a109f22008-07-04 16:56:05 +02001493 if (IS_ERR(file->private_data))
1494 err = PTR_ERR(file->private_data);
1495 else
1496 err = 0;
1497 }
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001498 mutex_unlock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001499
Louis Rilling2a109f22008-07-04 16:56:05 +02001500 return err;
Joel Becker7063fbf2005-12-15 14:29:43 -08001501}
1502
1503static int configfs_dir_close(struct inode *inode, struct file *file)
1504{
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001505 struct dentry * dentry = file->f_path.dentry;
Joel Becker7063fbf2005-12-15 14:29:43 -08001506 struct configfs_dirent * cursor = file->private_data;
1507
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001508 mutex_lock(&dentry->d_inode->i_mutex);
Louis Rilling6f610762008-06-16 19:00:58 +02001509 spin_lock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -08001510 list_del_init(&cursor->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +02001511 spin_unlock(&configfs_dirent_lock);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001512 mutex_unlock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001513
1514 release_configfs_dirent(cursor);
1515
1516 return 0;
1517}
1518
1519/* Relationship between s_mode and the DT_xxx types */
1520static inline unsigned char dt_type(struct configfs_dirent *sd)
1521{
1522 return (sd->s_mode >> 12) & 15;
1523}
1524
Al Viro52018852013-05-16 01:28:34 -04001525static int configfs_readdir(struct file *file, struct dir_context *ctx)
Joel Becker7063fbf2005-12-15 14:29:43 -08001526{
Al Viro52018852013-05-16 01:28:34 -04001527 struct dentry *dentry = file->f_path.dentry;
Al Virob7c177f2012-03-17 16:24:54 -04001528 struct super_block *sb = dentry->d_sb;
Joel Becker7063fbf2005-12-15 14:29:43 -08001529 struct configfs_dirent * parent_sd = dentry->d_fsdata;
Al Viro52018852013-05-16 01:28:34 -04001530 struct configfs_dirent *cursor = file->private_data;
Joel Becker7063fbf2005-12-15 14:29:43 -08001531 struct list_head *p, *q = &cursor->s_sibling;
Joel Becker24307aa2011-05-18 04:08:16 -07001532 ino_t ino = 0;
Joel Becker7063fbf2005-12-15 14:29:43 -08001533
Al Viro52018852013-05-16 01:28:34 -04001534 if (!dir_emit_dots(file, ctx))
1535 return 0;
1536 if (ctx->pos == 2) {
1537 spin_lock(&configfs_dirent_lock);
1538 list_move(q, &parent_sd->s_children);
1539 spin_unlock(&configfs_dirent_lock);
1540 }
1541 for (p = q->next; p != &parent_sd->s_children; p = p->next) {
1542 struct configfs_dirent *next;
1543 const char *name;
1544 int len;
1545 struct inode *inode = NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -08001546
Al Viro52018852013-05-16 01:28:34 -04001547 next = list_entry(p, struct configfs_dirent, s_sibling);
1548 if (!next->s_element)
1549 continue;
Joel Becker7063fbf2005-12-15 14:29:43 -08001550
Al Viro52018852013-05-16 01:28:34 -04001551 name = configfs_get_name(next);
1552 len = strlen(name);
Joel Becker24307aa2011-05-18 04:08:16 -07001553
Al Viro52018852013-05-16 01:28:34 -04001554 /*
1555 * We'll have a dentry and an inode for
1556 * PINNED items and for open attribute
1557 * files. We lock here to prevent a race
1558 * with configfs_d_iput() clearing
1559 * s_dentry before calling iput().
1560 *
1561 * Why do we go to the trouble? If
1562 * someone has an attribute file open,
1563 * the inode number should match until
1564 * they close it. Beyond that, we don't
1565 * care.
1566 */
1567 spin_lock(&configfs_dirent_lock);
1568 dentry = next->s_dentry;
1569 if (dentry)
1570 inode = dentry->d_inode;
1571 if (inode)
1572 ino = inode->i_ino;
1573 spin_unlock(&configfs_dirent_lock);
1574 if (!inode)
1575 ino = iunique(sb, 2);
Joel Becker7063fbf2005-12-15 14:29:43 -08001576
Al Viro52018852013-05-16 01:28:34 -04001577 if (!dir_emit(ctx, name, len, ino, dt_type(next)))
1578 return 0;
Joel Becker7063fbf2005-12-15 14:29:43 -08001579
Al Viro52018852013-05-16 01:28:34 -04001580 spin_lock(&configfs_dirent_lock);
1581 list_move(q, p);
1582 spin_unlock(&configfs_dirent_lock);
1583 p = q;
1584 ctx->pos++;
Joel Becker7063fbf2005-12-15 14:29:43 -08001585 }
1586 return 0;
1587}
1588
Andrew Morton965c8e52012-12-17 15:59:39 -08001589static loff_t configfs_dir_lseek(struct file *file, loff_t offset, int whence)
Joel Becker7063fbf2005-12-15 14:29:43 -08001590{
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001591 struct dentry * dentry = file->f_path.dentry;
Joel Becker7063fbf2005-12-15 14:29:43 -08001592
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001593 mutex_lock(&dentry->d_inode->i_mutex);
Andrew Morton965c8e52012-12-17 15:59:39 -08001594 switch (whence) {
Joel Becker7063fbf2005-12-15 14:29:43 -08001595 case 1:
1596 offset += file->f_pos;
1597 case 0:
1598 if (offset >= 0)
1599 break;
1600 default:
Al Viro496ad9a2013-01-23 17:07:38 -05001601 mutex_unlock(&file_inode(file)->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001602 return -EINVAL;
1603 }
1604 if (offset != file->f_pos) {
1605 file->f_pos = offset;
1606 if (file->f_pos >= 2) {
1607 struct configfs_dirent *sd = dentry->d_fsdata;
1608 struct configfs_dirent *cursor = file->private_data;
1609 struct list_head *p;
1610 loff_t n = file->f_pos - 2;
1611
Louis Rilling6f610762008-06-16 19:00:58 +02001612 spin_lock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -08001613 list_del(&cursor->s_sibling);
1614 p = sd->s_children.next;
1615 while (n && p != &sd->s_children) {
1616 struct configfs_dirent *next;
1617 next = list_entry(p, struct configfs_dirent,
1618 s_sibling);
1619 if (next->s_element)
1620 n--;
1621 p = p->next;
1622 }
1623 list_add_tail(&cursor->s_sibling, p);
Louis Rilling6f610762008-06-16 19:00:58 +02001624 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -08001625 }
1626 }
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001627 mutex_unlock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001628 return offset;
1629}
1630
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -08001631const struct file_operations configfs_dir_operations = {
Joel Becker7063fbf2005-12-15 14:29:43 -08001632 .open = configfs_dir_open,
1633 .release = configfs_dir_close,
1634 .llseek = configfs_dir_lseek,
1635 .read = generic_read_dir,
Al Viro52018852013-05-16 01:28:34 -04001636 .iterate = configfs_readdir,
Joel Becker7063fbf2005-12-15 14:29:43 -08001637};
1638
1639int configfs_register_subsystem(struct configfs_subsystem *subsys)
1640{
1641 int err;
1642 struct config_group *group = &subsys->su_group;
Joel Becker7063fbf2005-12-15 14:29:43 -08001643 struct dentry *dentry;
Al Virob7c177f2012-03-17 16:24:54 -04001644 struct dentry *root;
Joel Becker7063fbf2005-12-15 14:29:43 -08001645 struct configfs_dirent *sd;
1646
Al Viro2a152ad2012-03-17 16:53:29 -04001647 root = configfs_pin_fs();
1648 if (IS_ERR(root))
1649 return PTR_ERR(root);
Joel Becker7063fbf2005-12-15 14:29:43 -08001650
1651 if (!group->cg_item.ci_name)
1652 group->cg_item.ci_name = group->cg_item.ci_namebuf;
1653
Al Virob7c177f2012-03-17 16:24:54 -04001654 sd = root->d_fsdata;
Joel Becker7063fbf2005-12-15 14:29:43 -08001655 link_group(to_config_group(sd->s_element), group);
1656
Al Virob7c177f2012-03-17 16:24:54 -04001657 mutex_lock_nested(&root->d_inode->i_mutex, I_MUTEX_PARENT);
Joel Becker7063fbf2005-12-15 14:29:43 -08001658
Joel Becker7063fbf2005-12-15 14:29:43 -08001659 err = -ENOMEM;
Al Viroec193cf2013-07-14 17:16:52 +04001660 dentry = d_alloc_name(root, group->cg_item.ci_name);
Joel Beckerafdf04e2007-03-05 15:49:49 -08001661 if (dentry) {
1662 d_add(dentry, NULL);
Joel Becker7063fbf2005-12-15 14:29:43 -08001663
Joel Beckerafdf04e2007-03-05 15:49:49 -08001664 err = configfs_attach_group(sd->s_element, &group->cg_item,
1665 dentry);
1666 if (err) {
Joel Beckerdf7f9962011-02-22 01:09:49 -08001667 BUG_ON(dentry->d_inode);
1668 d_drop(dentry);
Joel Beckerafdf04e2007-03-05 15:49:49 -08001669 dput(dentry);
Louis Rilling2a109f22008-07-04 16:56:05 +02001670 } else {
1671 spin_lock(&configfs_dirent_lock);
1672 configfs_dir_set_ready(dentry->d_fsdata);
1673 spin_unlock(&configfs_dirent_lock);
Joel Beckerafdf04e2007-03-05 15:49:49 -08001674 }
1675 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001676
Al Virob7c177f2012-03-17 16:24:54 -04001677 mutex_unlock(&root->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001678
Joel Beckerafdf04e2007-03-05 15:49:49 -08001679 if (err) {
1680 unlink_group(group);
1681 configfs_release_fs();
Joel Becker7063fbf2005-12-15 14:29:43 -08001682 }
1683
1684 return err;
1685}
1686
1687void configfs_unregister_subsystem(struct configfs_subsystem *subsys)
1688{
1689 struct config_group *group = &subsys->su_group;
1690 struct dentry *dentry = group->cg_item.ci_dentry;
Al Virob7c177f2012-03-17 16:24:54 -04001691 struct dentry *root = dentry->d_sb->s_root;
Joel Becker7063fbf2005-12-15 14:29:43 -08001692
Al Virob7c177f2012-03-17 16:24:54 -04001693 if (dentry->d_parent != root) {
Fabian Frederick1d88aa42014-06-04 16:05:59 -07001694 pr_err("Tried to unregister non-subsystem!\n");
Joel Becker7063fbf2005-12-15 14:29:43 -08001695 return;
1696 }
1697
Al Virob7c177f2012-03-17 16:24:54 -04001698 mutex_lock_nested(&root->d_inode->i_mutex,
Mark Fasheh55ed1602006-10-20 14:55:54 -07001699 I_MUTEX_PARENT);
1700 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD);
Louis Rilling9a73d782008-06-20 14:09:22 +02001701 mutex_lock(&configfs_symlink_mutex);
Louis Rillingb3e76af2008-06-16 19:01:01 +02001702 spin_lock(&configfs_dirent_lock);
Louis Rilling6d8344b2008-06-16 19:01:02 +02001703 if (configfs_detach_prep(dentry, NULL)) {
Fabian Frederick1d88aa42014-06-04 16:05:59 -07001704 pr_err("Tried to unregister non-empty subsystem!\n");
Joel Becker7063fbf2005-12-15 14:29:43 -08001705 }
Louis Rillingb3e76af2008-06-16 19:01:01 +02001706 spin_unlock(&configfs_dirent_lock);
Louis Rilling9a73d782008-06-20 14:09:22 +02001707 mutex_unlock(&configfs_symlink_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001708 configfs_detach_group(&group->cg_item);
1709 dentry->d_inode->i_flags |= S_DEAD;
Al Virod83c49f2010-04-30 17:17:09 -04001710 dont_mount(dentry);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001711 mutex_unlock(&dentry->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001712
1713 d_delete(dentry);
1714
Al Virob7c177f2012-03-17 16:24:54 -04001715 mutex_unlock(&root->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001716
1717 dput(dentry);
1718
1719 unlink_group(group);
1720 configfs_release_fs();
1721}
1722
1723EXPORT_SYMBOL(configfs_register_subsystem);
1724EXPORT_SYMBOL(configfs_unregister_subsystem);