blob: a1985a9ad2d640f07c4663de421c36aff3fab8f2 [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);
Sahitya Tummala79cb5052019-01-03 16:48:15 +053061 /*
62 * Set sd->s_dentry to null only when this dentry is the one
63 * that is going to be killed. Otherwise configfs_d_iput may
64 * run just after configfs_attach_attr and set sd->s_dentry to
65 * NULL even it's still in use.
Junxiao Bi76ae2812013-11-21 14:31:56 -080066 */
Sahitya Tummala79cb5052019-01-03 16:48:15 +053067 if (sd->s_dentry == dentry)
Junxiao Bi76ae2812013-11-21 14:31:56 -080068 sd->s_dentry = NULL;
69
Joel Becker24307aa2011-05-18 04:08:16 -070070 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -080071 configfs_put(sd);
72 }
73 iput(inode);
74}
75
Al Virod463a0c2011-01-12 16:41:05 -050076const struct dentry_operations configfs_dentry_ops = {
Joel Becker7063fbf2005-12-15 14:29:43 -080077 .d_iput = configfs_d_iput,
Al Virob26d4cd2013-10-25 18:47:37 -040078 .d_delete = always_delete_dentry,
Joel Becker7063fbf2005-12-15 14:29:43 -080079};
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
Al Viroc88b1e72015-01-29 00:17:57 -0500241static void init_dir(struct inode * inode)
Joel Becker7063fbf2005-12-15 14:29:43 -0800242{
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}
249
Al Viroc88b1e72015-01-29 00:17:57 -0500250static void configfs_init_file(struct inode * inode)
Joel Becker7063fbf2005-12-15 14:29:43 -0800251{
252 inode->i_size = PAGE_SIZE;
253 inode->i_fop = &configfs_file_operations;
Joel Becker7063fbf2005-12-15 14:29:43 -0800254}
255
Pantelis Antoniou03607ac2015-10-22 23:30:04 +0300256static void configfs_init_bin_file(struct inode *inode)
257{
258 inode->i_size = 0;
259 inode->i_fop = &configfs_bin_file_operations;
260}
261
Al Viroc88b1e72015-01-29 00:17:57 -0500262static void init_symlink(struct inode * inode)
Joel Becker7063fbf2005-12-15 14:29:43 -0800263{
264 inode->i_op = &configfs_symlink_inode_operations;
Joel Becker7063fbf2005-12-15 14:29:43 -0800265}
266
Joel Becker7063fbf2005-12-15 14:29:43 -0800267/**
268 * configfs_create_dir - create a directory for an config_item.
269 * @item: config_itemwe're creating directory for.
270 * @dentry: config_item's dentry.
Louis Rilling2a109f22008-07-04 16:56:05 +0200271 *
272 * Note: user-created entries won't be allowed under this new directory
273 * until it is validated by configfs_dir_set_ready()
Joel Becker7063fbf2005-12-15 14:29:43 -0800274 */
275
Al Viro1cf97d02015-01-29 00:20:49 -0500276static int configfs_create_dir(struct config_item *item, struct dentry *dentry)
Joel Becker7063fbf2005-12-15 14:29:43 -0800277{
Al Viro1cf97d02015-01-29 00:20:49 -0500278 int error;
279 umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
280 struct dentry *p = dentry->d_parent;
281
282 BUG_ON(!item);
283
284 error = configfs_dirent_exists(p->d_fsdata, dentry->d_name.name);
285 if (unlikely(error))
286 return error;
287
288 error = configfs_make_dirent(p->d_fsdata, dentry, item, mode,
289 CONFIGFS_DIR | CONFIGFS_USET_CREATING);
290 if (unlikely(error))
291 return error;
292
293 configfs_set_dir_dirent_depth(p->d_fsdata, dentry->d_fsdata);
294 error = configfs_create(dentry, mode, init_dir);
295 if (!error) {
David Howells2b0143b2015-03-17 22:25:59 +0000296 inc_nlink(d_inode(p));
Joel Becker7063fbf2005-12-15 14:29:43 -0800297 item->ci_dentry = dentry;
Al Viro1cf97d02015-01-29 00:20:49 -0500298 } else {
299 struct configfs_dirent *sd = dentry->d_fsdata;
300 if (sd) {
301 spin_lock(&configfs_dirent_lock);
302 list_del_init(&sd->s_sibling);
303 spin_unlock(&configfs_dirent_lock);
304 configfs_put(sd);
305 }
306 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800307 return error;
308}
309
Louis Rilling2a109f22008-07-04 16:56:05 +0200310/*
311 * Allow userspace to create new entries under a new directory created with
312 * configfs_create_dir(), and under all of its chidlren directories recursively.
313 * @sd configfs_dirent of the new directory to validate
314 *
315 * Caller must hold configfs_dirent_lock.
316 */
317static void configfs_dir_set_ready(struct configfs_dirent *sd)
318{
319 struct configfs_dirent *child_sd;
320
321 sd->s_type &= ~CONFIGFS_USET_CREATING;
322 list_for_each_entry(child_sd, &sd->s_children, s_sibling)
323 if (child_sd->s_type & CONFIGFS_USET_CREATING)
324 configfs_dir_set_ready(child_sd);
325}
326
327/*
328 * Check that a directory does not belong to a directory hierarchy being
329 * attached and not validated yet.
330 * @sd configfs_dirent of the directory to check
331 *
332 * @return non-zero iff the directory was validated
333 *
334 * Note: takes configfs_dirent_lock, so the result may change from false to true
335 * in two consecutive calls, but never from true to false.
336 */
337int configfs_dirent_is_ready(struct configfs_dirent *sd)
338{
339 int ret;
340
341 spin_lock(&configfs_dirent_lock);
342 ret = !(sd->s_type & CONFIGFS_USET_CREATING);
343 spin_unlock(&configfs_dirent_lock);
344
345 return ret;
346}
347
Joel Becker7063fbf2005-12-15 14:29:43 -0800348int configfs_create_link(struct configfs_symlink *sl,
349 struct dentry *parent,
350 struct dentry *dentry)
351{
352 int err = 0;
353 umode_t mode = S_IFLNK | S_IRWXUGO;
354
Joel Becker3d0f89b2006-01-25 13:31:07 -0800355 err = configfs_make_dirent(parent->d_fsdata, dentry, sl, mode,
356 CONFIGFS_ITEM_LINK);
Joel Becker7063fbf2005-12-15 14:29:43 -0800357 if (!err) {
Joel Becker3d0f89b2006-01-25 13:31:07 -0800358 err = configfs_create(dentry, mode, init_symlink);
Nick Pigginfbc8d4c02011-01-07 17:49:21 +1100359 if (err) {
Joel Becker3d0f89b2006-01-25 13:31:07 -0800360 struct configfs_dirent *sd = dentry->d_fsdata;
361 if (sd) {
Louis Rilling6f610762008-06-16 19:00:58 +0200362 spin_lock(&configfs_dirent_lock);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800363 list_del_init(&sd->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +0200364 spin_unlock(&configfs_dirent_lock);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800365 configfs_put(sd);
366 }
367 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800368 }
369 return err;
370}
371
372static void remove_dir(struct dentry * d)
373{
374 struct dentry * parent = dget(d->d_parent);
375 struct configfs_dirent * sd;
376
377 sd = d->d_fsdata;
Louis Rilling6f610762008-06-16 19:00:58 +0200378 spin_lock(&configfs_dirent_lock);
Joel Beckere7515d02006-03-10 11:42:30 -0800379 list_del_init(&sd->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +0200380 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800381 configfs_put(sd);
David Howells2b0143b2015-03-17 22:25:59 +0000382 if (d_really_is_positive(d))
383 simple_rmdir(d_inode(parent),d);
Joel Becker7063fbf2005-12-15 14:29:43 -0800384
Al Viroa4555892014-10-21 20:11:25 -0400385 pr_debug(" o %pd removing done (%d)\n", d, d_count(d));
Joel Becker7063fbf2005-12-15 14:29:43 -0800386
387 dput(parent);
388}
389
390/**
391 * configfs_remove_dir - remove an config_item's directory.
392 * @item: config_item we're removing.
393 *
394 * The only thing special about this is that we remove any files in
395 * the directory before we remove the directory, and we've inlined
396 * what used to be configfs_rmdir() below, instead of calling separately.
Louis Rilling2e2ce172008-07-04 16:56:06 +0200397 *
398 * Caller holds the mutex of the item's inode
Joel Becker7063fbf2005-12-15 14:29:43 -0800399 */
400
401static void configfs_remove_dir(struct config_item * item)
402{
403 struct dentry * dentry = dget(item->ci_dentry);
404
405 if (!dentry)
406 return;
407
408 remove_dir(dentry);
409 /**
410 * Drop reference from dget() on entrance.
411 */
412 dput(dentry);
413}
414
415
416/* attaches attribute's configfs_dirent to the dentry corresponding to the
417 * attribute file
418 */
419static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry)
420{
421 struct configfs_attribute * attr = sd->s_element;
422 int error;
423
Junxiao Bi76ae2812013-11-21 14:31:56 -0800424 spin_lock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800425 dentry->d_fsdata = configfs_get(sd);
426 sd->s_dentry = dentry;
Junxiao Bi76ae2812013-11-21 14:31:56 -0800427 spin_unlock(&configfs_dirent_lock);
428
Dave Hansence8d2cd2007-10-16 23:31:13 -0700429 error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG,
Pantelis Antoniou03607ac2015-10-22 23:30:04 +0300430 (sd->s_type & CONFIGFS_ITEM_BIN_ATTR) ?
431 configfs_init_bin_file :
432 configfs_init_file);
Al Viro5cf3b562016-03-07 14:25:46 -0500433 if (error)
Joel Becker3d0f89b2006-01-25 13:31:07 -0800434 configfs_put(sd);
Al Viro5cf3b562016-03-07 14:25:46 -0500435 return error;
Joel Becker7063fbf2005-12-15 14:29:43 -0800436}
437
438static struct dentry * configfs_lookup(struct inode *dir,
439 struct dentry *dentry,
Al Viro00cd8dd2012-06-10 17:13:09 -0400440 unsigned int flags)
Joel Becker7063fbf2005-12-15 14:29:43 -0800441{
442 struct configfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
443 struct configfs_dirent * sd;
444 int found = 0;
Louis Rilling2a109f22008-07-04 16:56:05 +0200445 int err;
446
447 /*
448 * Fake invisibility if dir belongs to a group/default groups hierarchy
449 * being attached
450 *
451 * This forbids userspace to read/write attributes of items which may
452 * not complete their initialization, since the dentries of the
453 * attributes won't be instantiated.
454 */
455 err = -ENOENT;
456 if (!configfs_dirent_is_ready(parent_sd))
457 goto out;
Joel Becker7063fbf2005-12-15 14:29:43 -0800458
459 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
460 if (sd->s_type & CONFIGFS_NOT_PINNED) {
461 const unsigned char * name = configfs_get_name(sd);
462
463 if (strcmp(name, dentry->d_name.name))
464 continue;
465
466 found = 1;
467 err = configfs_attach_attr(sd, dentry);
468 break;
469 }
470 }
471
472 if (!found) {
473 /*
474 * If it doesn't exist and it isn't a NOT_PINNED item,
475 * it must be negative.
476 */
Nick Pigginfbc8d4c02011-01-07 17:49:21 +1100477 if (dentry->d_name.len > NAME_MAX)
478 return ERR_PTR(-ENAMETOOLONG);
Nick Pigginfbc8d4c02011-01-07 17:49:21 +1100479 d_add(dentry, NULL);
480 return NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -0800481 }
482
Louis Rilling2a109f22008-07-04 16:56:05 +0200483out:
Joel Becker7063fbf2005-12-15 14:29:43 -0800484 return ERR_PTR(err);
485}
486
487/*
488 * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are
Louis Rillingb3e76af2008-06-16 19:01:01 +0200489 * attributes and are removed by rmdir(). We recurse, setting
490 * CONFIGFS_USET_DROPPING on all children that are candidates for
491 * default detach.
492 * If there is an error, the caller will reset the flags via
493 * configfs_detach_rollback().
Joel Becker7063fbf2005-12-15 14:29:43 -0800494 */
Al Viro48f35b72016-04-12 00:37:59 -0400495static int configfs_detach_prep(struct dentry *dentry, struct dentry **wait)
Joel Becker7063fbf2005-12-15 14:29:43 -0800496{
497 struct configfs_dirent *parent_sd = dentry->d_fsdata;
498 struct configfs_dirent *sd;
499 int ret;
500
Louis Rilling4768e9b2008-06-23 14:16:17 +0200501 /* Mark that we're trying to drop the group */
502 parent_sd->s_type |= CONFIGFS_USET_DROPPING;
503
Joel Becker7063fbf2005-12-15 14:29:43 -0800504 ret = -EBUSY;
505 if (!list_empty(&parent_sd->s_links))
506 goto out;
507
508 ret = 0;
509 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
Louis Rilling99cefda2008-06-27 13:10:25 +0200510 if (!sd->s_element ||
511 (sd->s_type & CONFIGFS_NOT_PINNED))
Joel Becker7063fbf2005-12-15 14:29:43 -0800512 continue;
513 if (sd->s_type & CONFIGFS_USET_DEFAULT) {
Louis Rilling6d8344b2008-06-16 19:01:02 +0200514 /* Abort if racing with mkdir() */
515 if (sd->s_type & CONFIGFS_USET_IN_MKDIR) {
Al Viro48f35b72016-04-12 00:37:59 -0400516 if (wait)
517 *wait= dget(sd->s_dentry);
Louis Rilling6d8344b2008-06-16 19:01:02 +0200518 return -EAGAIN;
519 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800520
Joel Becker631d1fe2007-06-18 18:06:09 -0700521 /*
522 * Yup, recursive. If there's a problem, blame
523 * deep nesting of default_groups
524 */
Al Viro48f35b72016-04-12 00:37:59 -0400525 ret = configfs_detach_prep(sd->s_dentry, wait);
Joel Becker7063fbf2005-12-15 14:29:43 -0800526 if (!ret)
Joel Beckere7515d02006-03-10 11:42:30 -0800527 continue;
Joel Becker7063fbf2005-12-15 14:29:43 -0800528 } else
529 ret = -ENOTEMPTY;
530
531 break;
532 }
533
534out:
535 return ret;
536}
537
538/*
Louis Rillingb3e76af2008-06-16 19:01:01 +0200539 * Walk the tree, resetting CONFIGFS_USET_DROPPING wherever it was
Joel Becker7063fbf2005-12-15 14:29:43 -0800540 * set.
541 */
542static void configfs_detach_rollback(struct dentry *dentry)
543{
544 struct configfs_dirent *parent_sd = dentry->d_fsdata;
545 struct configfs_dirent *sd;
546
Louis Rilling4768e9b2008-06-23 14:16:17 +0200547 parent_sd->s_type &= ~CONFIGFS_USET_DROPPING;
548
549 list_for_each_entry(sd, &parent_sd->s_children, s_sibling)
550 if (sd->s_type & CONFIGFS_USET_DEFAULT)
Joel Becker7063fbf2005-12-15 14:29:43 -0800551 configfs_detach_rollback(sd->s_dentry);
Joel Becker7063fbf2005-12-15 14:29:43 -0800552}
553
554static void detach_attrs(struct config_item * item)
555{
556 struct dentry * dentry = dget(item->ci_dentry);
557 struct configfs_dirent * parent_sd;
558 struct configfs_dirent * sd, * tmp;
559
560 if (!dentry)
561 return;
562
563 pr_debug("configfs %s: dropping attrs for dir\n",
564 dentry->d_name.name);
565
566 parent_sd = dentry->d_fsdata;
567 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
568 if (!sd->s_element || !(sd->s_type & CONFIGFS_NOT_PINNED))
569 continue;
Louis Rilling6f610762008-06-16 19:00:58 +0200570 spin_lock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800571 list_del_init(&sd->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +0200572 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800573 configfs_drop_dentry(sd, dentry);
574 configfs_put(sd);
575 }
576
577 /**
578 * Drop reference from dget() on entrance.
579 */
580 dput(dentry);
581}
582
583static int populate_attrs(struct config_item *item)
584{
585 struct config_item_type *t = item->ci_type;
586 struct configfs_attribute *attr;
Pantelis Antoniou03607ac2015-10-22 23:30:04 +0300587 struct configfs_bin_attribute *bin_attr;
Joel Becker7063fbf2005-12-15 14:29:43 -0800588 int error = 0;
589 int i;
590
591 if (!t)
592 return -EINVAL;
593 if (t->ct_attrs) {
594 for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) {
595 if ((error = configfs_create_file(item, attr)))
596 break;
597 }
598 }
Pantelis Antoniou03607ac2015-10-22 23:30:04 +0300599 if (t->ct_bin_attrs) {
600 for (i = 0; (bin_attr = t->ct_bin_attrs[i]) != NULL; i++) {
601 error = configfs_create_bin_file(item, bin_attr);
602 if (error)
603 break;
604 }
605 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800606
607 if (error)
608 detach_attrs(item);
609
610 return error;
611}
612
613static int configfs_attach_group(struct config_item *parent_item,
614 struct config_item *item,
615 struct dentry *dentry);
616static void configfs_detach_group(struct config_item *item);
617
618static void detach_groups(struct config_group *group)
619{
620 struct dentry * dentry = dget(group->cg_item.ci_dentry);
621 struct dentry *child;
622 struct configfs_dirent *parent_sd;
623 struct configfs_dirent *sd, *tmp;
624
625 if (!dentry)
626 return;
627
628 parent_sd = dentry->d_fsdata;
629 list_for_each_entry_safe(sd, tmp, &parent_sd->s_children, s_sibling) {
630 if (!sd->s_element ||
631 !(sd->s_type & CONFIGFS_USET_DEFAULT))
632 continue;
633
634 child = sd->s_dentry;
635
Al Viro59551022016-01-22 15:40:57 -0500636 inode_lock(d_inode(child));
Louis Rillingb3e76af2008-06-16 19:01:01 +0200637
Joel Becker7063fbf2005-12-15 14:29:43 -0800638 configfs_detach_group(sd->s_element);
David Howells2b0143b2015-03-17 22:25:59 +0000639 d_inode(child)->i_flags |= S_DEAD;
Al Virod83c49f2010-04-30 17:17:09 -0400640 dont_mount(child);
Joel Becker7063fbf2005-12-15 14:29:43 -0800641
Al Viro59551022016-01-22 15:40:57 -0500642 inode_unlock(d_inode(child));
Joel Becker7063fbf2005-12-15 14:29:43 -0800643
644 d_delete(child);
645 dput(child);
646 }
647
648 /**
649 * Drop reference from dget() on entrance.
650 */
651 dput(dentry);
652}
653
654/*
655 * This fakes mkdir(2) on a default_groups[] entry. It
656 * creates a dentry, attachs it, and then does fixup
657 * on the sd->s_type.
658 *
659 * We could, perhaps, tweak our parent's ->mkdir for a minute and
660 * try using vfs_mkdir. Just a thought.
661 */
662static int create_default_group(struct config_group *parent_group,
663 struct config_group *group)
664{
665 int ret;
Joel Becker7063fbf2005-12-15 14:29:43 -0800666 struct configfs_dirent *sd;
667 /* We trust the caller holds a reference to parent */
668 struct dentry *child, *parent = parent_group->cg_item.ci_dentry;
669
670 if (!group->cg_item.ci_name)
671 group->cg_item.ci_name = group->cg_item.ci_namebuf;
Joel Becker7063fbf2005-12-15 14:29:43 -0800672
673 ret = -ENOMEM;
Al Viroec193cf2013-07-14 17:16:52 +0400674 child = d_alloc_name(parent, group->cg_item.ci_name);
Joel Becker7063fbf2005-12-15 14:29:43 -0800675 if (child) {
676 d_add(child, NULL);
677
678 ret = configfs_attach_group(&parent_group->cg_item,
679 &group->cg_item, child);
680 if (!ret) {
681 sd = child->d_fsdata;
682 sd->s_type |= CONFIGFS_USET_DEFAULT;
683 } else {
David Howells2b0143b2015-03-17 22:25:59 +0000684 BUG_ON(d_inode(child));
Joel Beckerdf7f9962011-02-22 01:09:49 -0800685 d_drop(child);
Joel Becker7063fbf2005-12-15 14:29:43 -0800686 dput(child);
687 }
688 }
689
690 return ret;
691}
692
693static int populate_groups(struct config_group *group)
694{
695 struct config_group *new_group;
Joel Becker7063fbf2005-12-15 14:29:43 -0800696 int ret = 0;
Joel Becker7063fbf2005-12-15 14:29:43 -0800697
Christoph Hellwig1ae16022016-02-26 11:02:14 +0100698 list_for_each_entry(new_group, &group->default_groups, group_entry) {
699 ret = create_default_group(group, new_group);
700 if (ret) {
701 detach_groups(group);
702 break;
Joel Becker7063fbf2005-12-15 14:29:43 -0800703 }
Joel Becker7063fbf2005-12-15 14:29:43 -0800704 }
705
Joel Becker7063fbf2005-12-15 14:29:43 -0800706 return ret;
707}
708
Christoph Hellwig1ae16022016-02-26 11:02:14 +0100709void configfs_remove_default_groups(struct config_group *group)
710{
711 struct config_group *g, *n;
712
713 list_for_each_entry_safe(g, n, &group->default_groups, group_entry) {
714 list_del(&g->group_entry);
715 config_item_put(&g->cg_item);
716 }
717}
718EXPORT_SYMBOL(configfs_remove_default_groups);
719
Joel Becker7063fbf2005-12-15 14:29:43 -0800720/*
721 * All of link_obj/unlink_obj/link_group/unlink_group require that
Joel Beckere6bd07a2007-07-06 23:33:17 -0700722 * subsys->su_mutex is held.
Joel Becker7063fbf2005-12-15 14:29:43 -0800723 */
724
725static void unlink_obj(struct config_item *item)
726{
727 struct config_group *group;
728
729 group = item->ci_group;
730 if (group) {
731 list_del_init(&item->ci_entry);
732
733 item->ci_group = NULL;
734 item->ci_parent = NULL;
Joel Beckereed7a0d2006-04-11 21:37:20 -0700735
736 /* Drop the reference for ci_entry */
Joel Becker7063fbf2005-12-15 14:29:43 -0800737 config_item_put(item);
738
Joel Beckereed7a0d2006-04-11 21:37:20 -0700739 /* Drop the reference for ci_parent */
Joel Becker7063fbf2005-12-15 14:29:43 -0800740 config_group_put(group);
741 }
742}
743
744static void link_obj(struct config_item *parent_item, struct config_item *item)
745{
Joel Beckereed7a0d2006-04-11 21:37:20 -0700746 /*
747 * Parent seems redundant with group, but it makes certain
748 * traversals much nicer.
749 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800750 item->ci_parent = parent_item;
Joel Beckereed7a0d2006-04-11 21:37:20 -0700751
752 /*
753 * We hold a reference on the parent for the child's ci_parent
754 * link.
755 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800756 item->ci_group = config_group_get(to_config_group(parent_item));
757 list_add_tail(&item->ci_entry, &item->ci_group->cg_children);
758
Joel Beckereed7a0d2006-04-11 21:37:20 -0700759 /*
760 * We hold a reference on the child for ci_entry on the parent's
761 * cg_children
762 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800763 config_item_get(item);
764}
765
766static void unlink_group(struct config_group *group)
767{
Joel Becker7063fbf2005-12-15 14:29:43 -0800768 struct config_group *new_group;
769
Christoph Hellwig1ae16022016-02-26 11:02:14 +0100770 list_for_each_entry(new_group, &group->default_groups, group_entry)
771 unlink_group(new_group);
Joel Becker7063fbf2005-12-15 14:29:43 -0800772
773 group->cg_subsys = NULL;
774 unlink_obj(&group->cg_item);
775}
776
777static void link_group(struct config_group *parent_group, struct config_group *group)
778{
Joel Becker7063fbf2005-12-15 14:29:43 -0800779 struct config_group *new_group;
780 struct configfs_subsystem *subsys = NULL; /* gcc is a turd */
781
782 link_obj(&parent_group->cg_item, &group->cg_item);
783
784 if (parent_group->cg_subsys)
785 subsys = parent_group->cg_subsys;
786 else if (configfs_is_root(&parent_group->cg_item))
787 subsys = to_configfs_subsystem(group);
788 else
789 BUG();
790 group->cg_subsys = subsys;
791
Christoph Hellwig1ae16022016-02-26 11:02:14 +0100792 list_for_each_entry(new_group, &group->default_groups, group_entry)
793 link_group(group, new_group);
Joel Becker7063fbf2005-12-15 14:29:43 -0800794}
795
796/*
797 * The goal is that configfs_attach_item() (and
798 * configfs_attach_group()) can be called from either the VFS or this
799 * module. That is, they assume that the items have been created,
800 * the dentry allocated, and the dcache is all ready to go.
801 *
802 * If they fail, they must clean up after themselves as if they
803 * had never been called. The caller (VFS or local function) will
804 * handle cleaning up the dcache bits.
805 *
806 * configfs_detach_group() and configfs_detach_item() behave similarly on
807 * the way out. They assume that the proper semaphores are held, they
808 * clean up the configfs items, and they expect their callers will
809 * handle the dcache bits.
810 */
811static int configfs_attach_item(struct config_item *parent_item,
812 struct config_item *item,
813 struct dentry *dentry)
814{
815 int ret;
816
817 ret = configfs_create_dir(item, dentry);
818 if (!ret) {
819 ret = populate_attrs(item);
820 if (ret) {
Louis Rilling2e2ce172008-07-04 16:56:06 +0200821 /*
822 * We are going to remove an inode and its dentry but
823 * the VFS may already have hit and used them. Thus,
824 * we must lock them as rmdir() would.
825 */
Al Viro59551022016-01-22 15:40:57 -0500826 inode_lock(d_inode(dentry));
Joel Becker7063fbf2005-12-15 14:29:43 -0800827 configfs_remove_dir(item);
David Howells2b0143b2015-03-17 22:25:59 +0000828 d_inode(dentry)->i_flags |= S_DEAD;
Al Virod83c49f2010-04-30 17:17:09 -0400829 dont_mount(dentry);
Al Viro59551022016-01-22 15:40:57 -0500830 inode_unlock(d_inode(dentry));
Joel Becker7063fbf2005-12-15 14:29:43 -0800831 d_delete(dentry);
832 }
833 }
834
835 return ret;
836}
837
Louis Rilling2e2ce172008-07-04 16:56:06 +0200838/* Caller holds the mutex of the item's inode */
Joel Becker7063fbf2005-12-15 14:29:43 -0800839static void configfs_detach_item(struct config_item *item)
840{
841 detach_attrs(item);
842 configfs_remove_dir(item);
843}
844
845static int configfs_attach_group(struct config_item *parent_item,
846 struct config_item *item,
847 struct dentry *dentry)
848{
849 int ret;
850 struct configfs_dirent *sd;
851
852 ret = configfs_attach_item(parent_item, item, dentry);
853 if (!ret) {
854 sd = dentry->d_fsdata;
855 sd->s_type |= CONFIGFS_USET_DIR;
856
Louis Rilling2e2ce172008-07-04 16:56:06 +0200857 /*
858 * FYI, we're faking mkdir in populate_groups()
859 * We must lock the group's inode to avoid races with the VFS
860 * which can already hit the inode and try to add/remove entries
861 * under it.
862 *
863 * We must also lock the inode to remove it safely in case of
864 * error, as rmdir() would.
865 */
Al Viro59551022016-01-22 15:40:57 -0500866 inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);
Louis Rillinge74cc062009-01-28 19:18:32 +0100867 configfs_adjust_dir_dirent_depth_before_populate(sd);
Joel Becker7063fbf2005-12-15 14:29:43 -0800868 ret = populate_groups(to_config_group(item));
869 if (ret) {
870 configfs_detach_item(item);
David Howells2b0143b2015-03-17 22:25:59 +0000871 d_inode(dentry)->i_flags |= S_DEAD;
Al Virod83c49f2010-04-30 17:17:09 -0400872 dont_mount(dentry);
Joel Becker7063fbf2005-12-15 14:29:43 -0800873 }
Louis Rillinge74cc062009-01-28 19:18:32 +0100874 configfs_adjust_dir_dirent_depth_after_populate(sd);
Al Viro59551022016-01-22 15:40:57 -0500875 inode_unlock(d_inode(dentry));
Louis Rilling2e2ce172008-07-04 16:56:06 +0200876 if (ret)
877 d_delete(dentry);
Joel Becker7063fbf2005-12-15 14:29:43 -0800878 }
879
880 return ret;
881}
882
Louis Rilling2e2ce172008-07-04 16:56:06 +0200883/* Caller holds the mutex of the group's inode */
Joel Becker7063fbf2005-12-15 14:29:43 -0800884static void configfs_detach_group(struct config_item *item)
885{
886 detach_groups(to_config_group(item));
887 configfs_detach_item(item);
888}
889
890/*
Joel Becker299894c2006-10-06 17:33:23 -0700891 * After the item has been detached from the filesystem view, we are
892 * ready to tear it out of the hierarchy. Notify the client before
893 * we do that so they can perform any cleanup that requires
894 * navigating the hierarchy. A client does not need to provide this
895 * callback. The subsystem semaphore MUST be held by the caller, and
896 * references must be valid for both items. It also assumes the
897 * caller has validated ci_type.
898 */
899static void client_disconnect_notify(struct config_item *parent_item,
900 struct config_item *item)
901{
902 struct config_item_type *type;
903
904 type = parent_item->ci_type;
905 BUG_ON(!type);
906
907 if (type->ct_group_ops && type->ct_group_ops->disconnect_notify)
908 type->ct_group_ops->disconnect_notify(to_config_group(parent_item),
909 item);
910}
911
912/*
Joel Becker7063fbf2005-12-15 14:29:43 -0800913 * Drop the initial reference from make_item()/make_group()
914 * This function assumes that reference is held on item
915 * and that item holds a valid reference to the parent. Also, it
916 * assumes the caller has validated ci_type.
917 */
918static void client_drop_item(struct config_item *parent_item,
919 struct config_item *item)
920{
921 struct config_item_type *type;
922
923 type = parent_item->ci_type;
924 BUG_ON(!type);
925
Joel Beckereed7a0d2006-04-11 21:37:20 -0700926 /*
927 * If ->drop_item() exists, it is responsible for the
928 * config_item_put().
929 */
Joel Becker7063fbf2005-12-15 14:29:43 -0800930 if (type->ct_group_ops && type->ct_group_ops->drop_item)
931 type->ct_group_ops->drop_item(to_config_group(parent_item),
Joel Becker299894c2006-10-06 17:33:23 -0700932 item);
Joel Becker7063fbf2005-12-15 14:29:43 -0800933 else
934 config_item_put(item);
935}
936
Joel Becker631d1fe2007-06-18 18:06:09 -0700937#ifdef DEBUG
938static void configfs_dump_one(struct configfs_dirent *sd, int level)
939{
Fabian Frederickc6686932014-06-04 16:05:58 -0700940 pr_info("%*s\"%s\":\n", level, " ", configfs_get_name(sd));
Joel Becker631d1fe2007-06-18 18:06:09 -0700941
Fabian Frederickc6686932014-06-04 16:05:58 -0700942#define type_print(_type) if (sd->s_type & _type) pr_info("%*s %s\n", level, " ", #_type);
Joel Becker631d1fe2007-06-18 18:06:09 -0700943 type_print(CONFIGFS_ROOT);
944 type_print(CONFIGFS_DIR);
945 type_print(CONFIGFS_ITEM_ATTR);
946 type_print(CONFIGFS_ITEM_LINK);
947 type_print(CONFIGFS_USET_DIR);
948 type_print(CONFIGFS_USET_DEFAULT);
949 type_print(CONFIGFS_USET_DROPPING);
950#undef type_print
951}
952
953static int configfs_dump(struct configfs_dirent *sd, int level)
954{
955 struct configfs_dirent *child_sd;
956 int ret = 0;
957
958 configfs_dump_one(sd, level);
959
960 if (!(sd->s_type & (CONFIGFS_DIR|CONFIGFS_ROOT)))
961 return 0;
962
963 list_for_each_entry(child_sd, &sd->s_children, s_sibling) {
964 ret = configfs_dump(child_sd, level + 2);
965 if (ret)
966 break;
967 }
968
969 return ret;
970}
971#endif
972
973
974/*
975 * configfs_depend_item() and configfs_undepend_item()
976 *
977 * WARNING: Do not call these from a configfs callback!
978 *
979 * This describes these functions and their helpers.
980 *
981 * Allow another kernel system to depend on a config_item. If this
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300982 * happens, the item cannot go away until the dependent can live without
Joel Becker631d1fe2007-06-18 18:06:09 -0700983 * it. The idea is to give client modules as simple an interface as
984 * possible. When a system asks them to depend on an item, they just
985 * call configfs_depend_item(). If the item is live and the client
986 * driver is in good shape, we'll happily do the work for them.
987 *
988 * Why is the locking complex? Because configfs uses the VFS to handle
989 * all locking, but this function is called outside the normal
990 * VFS->configfs path. So it must take VFS locks to prevent the
991 * VFS->configfs stuff (configfs_mkdir(), configfs_rmdir(), etc). This is
992 * why you can't call these functions underneath configfs callbacks.
993 *
994 * Note, btw, that this can be called at *any* time, even when a configfs
995 * subsystem isn't registered, or when configfs is loading or unloading.
996 * Just like configfs_register_subsystem(). So we take the same
Louis Rilling420118c2009-01-28 19:18:33 +0100997 * precautions. We pin the filesystem. We lock configfs_dirent_lock.
998 * If we can find the target item in the
Joel Becker631d1fe2007-06-18 18:06:09 -0700999 * configfs tree, it must be part of the subsystem tree as well, so we
Louis Rilling420118c2009-01-28 19:18:33 +01001000 * do not need the subsystem semaphore. Holding configfs_dirent_lock helps
1001 * locking out mkdir() and rmdir(), who might be racing us.
Joel Becker631d1fe2007-06-18 18:06:09 -07001002 */
1003
1004/*
1005 * configfs_depend_prep()
1006 *
1007 * Only subdirectories count here. Files (CONFIGFS_NOT_PINNED) are
1008 * attributes. This is similar but not the same to configfs_detach_prep().
1009 * Note that configfs_detach_prep() expects the parent to be locked when it
1010 * is called, but we lock the parent *inside* configfs_depend_prep(). We
1011 * do that so we can unlock it if we find nothing.
1012 *
1013 * Here we do a depth-first search of the dentry hierarchy looking for
Louis Rilling420118c2009-01-28 19:18:33 +01001014 * our object.
1015 * We deliberately ignore items tagged as dropping since they are virtually
1016 * dead, as well as items in the middle of attachment since they virtually
1017 * do not exist yet. This completes the locking out of racing mkdir() and
1018 * rmdir().
1019 * Note: subdirectories in the middle of attachment start with s_type =
1020 * CONFIGFS_DIR|CONFIGFS_USET_CREATING set by create_dir(). When
1021 * CONFIGFS_USET_CREATING is set, we ignore the item. The actual set of
1022 * s_type is in configfs_new_dirent(), which has configfs_dirent_lock.
Joel Becker631d1fe2007-06-18 18:06:09 -07001023 *
Louis Rilling420118c2009-01-28 19:18:33 +01001024 * If the target is not found, -ENOENT is bubbled up.
Joel Becker631d1fe2007-06-18 18:06:09 -07001025 *
1026 * This adds a requirement that all config_items be unique!
1027 *
Louis Rilling420118c2009-01-28 19:18:33 +01001028 * This is recursive. There isn't
Joel Becker631d1fe2007-06-18 18:06:09 -07001029 * much on the stack, though, so folks that need this function - be careful
1030 * about your stack! Patches will be accepted to make it iterative.
1031 */
1032static int configfs_depend_prep(struct dentry *origin,
1033 struct config_item *target)
1034{
Wei Yongjun49deb4b2013-02-21 16:42:43 -08001035 struct configfs_dirent *child_sd, *sd;
Joel Becker631d1fe2007-06-18 18:06:09 -07001036 int ret = 0;
1037
Wei Yongjun49deb4b2013-02-21 16:42:43 -08001038 BUG_ON(!origin || !origin->d_fsdata);
1039 sd = origin->d_fsdata;
Joel Becker631d1fe2007-06-18 18:06:09 -07001040
Joel Becker631d1fe2007-06-18 18:06:09 -07001041 if (sd->s_element == target) /* Boo-yah */
1042 goto out;
1043
1044 list_for_each_entry(child_sd, &sd->s_children, s_sibling) {
Louis Rilling420118c2009-01-28 19:18:33 +01001045 if ((child_sd->s_type & CONFIGFS_DIR) &&
1046 !(child_sd->s_type & CONFIGFS_USET_DROPPING) &&
1047 !(child_sd->s_type & CONFIGFS_USET_CREATING)) {
Joel Becker631d1fe2007-06-18 18:06:09 -07001048 ret = configfs_depend_prep(child_sd->s_dentry,
1049 target);
1050 if (!ret)
1051 goto out; /* Child path boo-yah */
1052 }
1053 }
1054
1055 /* We looped all our children and didn't find target */
Joel Becker631d1fe2007-06-18 18:06:09 -07001056 ret = -ENOENT;
1057
1058out:
1059 return ret;
1060}
1061
Krzysztof Opasiak9fb434e2015-12-11 16:06:10 +01001062static int configfs_do_depend_item(struct dentry *subsys_dentry,
1063 struct config_item *target)
1064{
1065 struct configfs_dirent *p;
1066 int ret;
1067
1068 spin_lock(&configfs_dirent_lock);
1069 /* Scan the tree, return 0 if found */
1070 ret = configfs_depend_prep(subsys_dentry, target);
1071 if (ret)
1072 goto out_unlock_dirent_lock;
1073
1074 /*
1075 * We are sure that the item is not about to be removed by rmdir(), and
1076 * not in the middle of attachment by mkdir().
1077 */
1078 p = target->ci_dentry->d_fsdata;
1079 p->s_dependent_count += 1;
1080
1081out_unlock_dirent_lock:
1082 spin_unlock(&configfs_dirent_lock);
1083
1084 return ret;
1085}
1086
Krzysztof Opasiak9a70adf2015-12-11 16:06:11 +01001087static inline struct configfs_dirent *
1088configfs_find_subsys_dentry(struct configfs_dirent *root_sd,
1089 struct config_item *subsys_item)
1090{
1091 struct configfs_dirent *p;
1092 struct configfs_dirent *ret = NULL;
1093
1094 list_for_each_entry(p, &root_sd->s_children, s_sibling) {
1095 if (p->s_type & CONFIGFS_DIR &&
1096 p->s_element == subsys_item) {
1097 ret = p;
1098 break;
1099 }
1100 }
1101
1102 return ret;
1103}
1104
1105
Joel Becker631d1fe2007-06-18 18:06:09 -07001106int configfs_depend_item(struct configfs_subsystem *subsys,
1107 struct config_item *target)
1108{
1109 int ret;
Krzysztof Opasiak9a70adf2015-12-11 16:06:11 +01001110 struct configfs_dirent *subsys_sd;
Joel Becker631d1fe2007-06-18 18:06:09 -07001111 struct config_item *s_item = &subsys->su_group.cg_item;
Al Virob7c177f2012-03-17 16:24:54 -04001112 struct dentry *root;
Joel Becker631d1fe2007-06-18 18:06:09 -07001113
1114 /*
1115 * Pin the configfs filesystem. This means we can safely access
1116 * the root of the configfs filesystem.
1117 */
Al Viro2a152ad2012-03-17 16:53:29 -04001118 root = configfs_pin_fs();
1119 if (IS_ERR(root))
1120 return PTR_ERR(root);
Joel Becker631d1fe2007-06-18 18:06:09 -07001121
1122 /*
1123 * Next, lock the root directory. We're going to check that the
1124 * subsystem is really registered, and so we need to lock out
1125 * configfs_[un]register_subsystem().
1126 */
Al Viro59551022016-01-22 15:40:57 -05001127 inode_lock(d_inode(root));
Joel Becker631d1fe2007-06-18 18:06:09 -07001128
Krzysztof Opasiak9a70adf2015-12-11 16:06:11 +01001129 subsys_sd = configfs_find_subsys_dentry(root->d_fsdata, s_item);
Joel Becker631d1fe2007-06-18 18:06:09 -07001130 if (!subsys_sd) {
1131 ret = -ENOENT;
1132 goto out_unlock_fs;
1133 }
1134
1135 /* Ok, now we can trust subsys/s_item */
Krzysztof Opasiak9fb434e2015-12-11 16:06:10 +01001136 ret = configfs_do_depend_item(subsys_sd->s_dentry, target);
Joel Becker631d1fe2007-06-18 18:06:09 -07001137
Joel Becker631d1fe2007-06-18 18:06:09 -07001138out_unlock_fs:
Al Viro59551022016-01-22 15:40:57 -05001139 inode_unlock(d_inode(root));
Joel Becker631d1fe2007-06-18 18:06:09 -07001140
1141 /*
1142 * If we succeeded, the fs is pinned via other methods. If not,
1143 * we're done with it anyway. So release_fs() is always right.
1144 */
1145 configfs_release_fs();
1146
1147 return ret;
1148}
1149EXPORT_SYMBOL(configfs_depend_item);
1150
1151/*
1152 * Release the dependent linkage. This is much simpler than
1153 * configfs_depend_item() because we know that that the client driver is
1154 * pinned, thus the subsystem is pinned, and therefore configfs is pinned.
1155 */
Krzysztof Opasiak9a9e3412015-12-11 16:06:09 +01001156void configfs_undepend_item(struct config_item *target)
Joel Becker631d1fe2007-06-18 18:06:09 -07001157{
1158 struct configfs_dirent *sd;
1159
1160 /*
Louis Rilling420118c2009-01-28 19:18:33 +01001161 * Since we can trust everything is pinned, we just need
1162 * configfs_dirent_lock.
Joel Becker631d1fe2007-06-18 18:06:09 -07001163 */
Louis Rilling420118c2009-01-28 19:18:33 +01001164 spin_lock(&configfs_dirent_lock);
Joel Becker631d1fe2007-06-18 18:06:09 -07001165
1166 sd = target->ci_dentry->d_fsdata;
1167 BUG_ON(sd->s_dependent_count < 1);
1168
1169 sd->s_dependent_count -= 1;
1170
1171 /*
1172 * After this unlock, we cannot trust the item to stay alive!
1173 * DO NOT REFERENCE item after this unlock.
1174 */
Louis Rilling420118c2009-01-28 19:18:33 +01001175 spin_unlock(&configfs_dirent_lock);
Joel Becker631d1fe2007-06-18 18:06:09 -07001176}
1177EXPORT_SYMBOL(configfs_undepend_item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001178
Krzysztof Opasiakd79d75b2015-12-11 16:06:12 +01001179/*
1180 * caller_subsys is a caller's subsystem not target's. This is used to
1181 * determine if we should lock root and check subsys or not. When we are
1182 * in the same subsystem as our target there is no need to do locking as
1183 * we know that subsys is valid and is not unregistered during this function
1184 * as we are called from callback of one of his children and VFS holds a lock
1185 * on some inode. Otherwise we have to lock our root to ensure that target's
1186 * subsystem it is not unregistered during this function.
1187 */
1188int configfs_depend_item_unlocked(struct configfs_subsystem *caller_subsys,
1189 struct config_item *target)
1190{
1191 struct configfs_subsystem *target_subsys;
1192 struct config_group *root, *parent;
1193 struct configfs_dirent *subsys_sd;
1194 int ret = -ENOENT;
1195
1196 /* Disallow this function for configfs root */
1197 if (configfs_is_root(target))
1198 return -EINVAL;
1199
1200 parent = target->ci_group;
1201 /*
1202 * This may happen when someone is trying to depend root
1203 * directory of some subsystem
1204 */
1205 if (configfs_is_root(&parent->cg_item)) {
1206 target_subsys = to_configfs_subsystem(to_config_group(target));
1207 root = parent;
1208 } else {
1209 target_subsys = parent->cg_subsys;
1210 /* Find a cofnigfs root as we may need it for locking */
1211 for (root = parent; !configfs_is_root(&root->cg_item);
1212 root = root->cg_item.ci_group)
1213 ;
1214 }
1215
1216 if (target_subsys != caller_subsys) {
1217 /*
1218 * We are in other configfs subsystem, so we have to do
1219 * additional locking to prevent other subsystem from being
1220 * unregistered
1221 */
Al Viro59551022016-01-22 15:40:57 -05001222 inode_lock(d_inode(root->cg_item.ci_dentry));
Krzysztof Opasiakd79d75b2015-12-11 16:06:12 +01001223
1224 /*
1225 * As we are trying to depend item from other subsystem
1226 * we have to check if this subsystem is still registered
1227 */
1228 subsys_sd = configfs_find_subsys_dentry(
1229 root->cg_item.ci_dentry->d_fsdata,
1230 &target_subsys->su_group.cg_item);
1231 if (!subsys_sd)
1232 goto out_root_unlock;
1233 } else {
1234 subsys_sd = target_subsys->su_group.cg_item.ci_dentry->d_fsdata;
1235 }
1236
1237 /* Now we can execute core of depend item */
1238 ret = configfs_do_depend_item(subsys_sd->s_dentry, target);
1239
1240 if (target_subsys != caller_subsys)
1241out_root_unlock:
1242 /*
1243 * We were called from subsystem other than our target so we
1244 * took some locks so now it's time to release them
1245 */
Al Viro59551022016-01-22 15:40:57 -05001246 inode_unlock(d_inode(root->cg_item.ci_dentry));
Krzysztof Opasiakd79d75b2015-12-11 16:06:12 +01001247
1248 return ret;
1249}
1250EXPORT_SYMBOL(configfs_depend_item_unlocked);
1251
Al Viro18bb1db2011-07-26 01:41:39 -04001252static int configfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
Joel Becker7063fbf2005-12-15 14:29:43 -08001253{
Joel Beckera6795e92008-07-17 15:21:29 -07001254 int ret = 0;
1255 int module_got = 0;
1256 struct config_group *group = NULL;
1257 struct config_item *item = NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -08001258 struct config_item *parent_item;
1259 struct configfs_subsystem *subsys;
1260 struct configfs_dirent *sd;
1261 struct config_item_type *type;
Joel Becker70526b62008-06-17 15:34:32 -07001262 struct module *subsys_owner = NULL, *new_item_owner = NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -08001263 char *name;
1264
Joel Becker7063fbf2005-12-15 14:29:43 -08001265 sd = dentry->d_parent->d_fsdata;
Louis Rilling2a109f22008-07-04 16:56:05 +02001266
1267 /*
1268 * Fake invisibility if dir belongs to a group/default groups hierarchy
1269 * being attached
1270 */
1271 if (!configfs_dirent_is_ready(sd)) {
1272 ret = -ENOENT;
1273 goto out;
1274 }
1275
Joel Becker84efad12006-03-27 18:46:09 -08001276 if (!(sd->s_type & CONFIGFS_USET_DIR)) {
1277 ret = -EPERM;
1278 goto out;
1279 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001280
Joel Becker84efad12006-03-27 18:46:09 -08001281 /* Get a working ref for the duration of this function */
Joel Becker7063fbf2005-12-15 14:29:43 -08001282 parent_item = configfs_get_config_item(dentry->d_parent);
1283 type = parent_item->ci_type;
1284 subsys = to_config_group(parent_item)->cg_subsys;
1285 BUG_ON(!subsys);
1286
1287 if (!type || !type->ct_group_ops ||
1288 (!type->ct_group_ops->make_group &&
1289 !type->ct_group_ops->make_item)) {
Joel Becker84efad12006-03-27 18:46:09 -08001290 ret = -EPERM; /* Lack-of-mkdir returns -EPERM */
1291 goto out_put;
Joel Becker7063fbf2005-12-15 14:29:43 -08001292 }
1293
Joel Becker70526b62008-06-17 15:34:32 -07001294 /*
1295 * The subsystem may belong to a different module than the item
1296 * being created. We don't want to safely pin the new item but
1297 * fail to pin the subsystem it sits under.
1298 */
1299 if (!subsys->su_group.cg_item.ci_type) {
1300 ret = -EINVAL;
1301 goto out_put;
1302 }
1303 subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner;
1304 if (!try_module_get(subsys_owner)) {
1305 ret = -EINVAL;
1306 goto out_put;
1307 }
1308
Joel Becker7063fbf2005-12-15 14:29:43 -08001309 name = kmalloc(dentry->d_name.len + 1, GFP_KERNEL);
1310 if (!name) {
Joel Becker84efad12006-03-27 18:46:09 -08001311 ret = -ENOMEM;
Joel Becker70526b62008-06-17 15:34:32 -07001312 goto out_subsys_put;
Joel Becker7063fbf2005-12-15 14:29:43 -08001313 }
Joel Becker84efad12006-03-27 18:46:09 -08001314
Joel Becker7063fbf2005-12-15 14:29:43 -08001315 snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name);
1316
Joel Beckere6bd07a2007-07-06 23:33:17 -07001317 mutex_lock(&subsys->su_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001318 if (type->ct_group_ops->make_group) {
Joel Beckerf89ab862008-07-17 14:53:48 -07001319 group = type->ct_group_ops->make_group(to_config_group(parent_item), name);
Joel Beckera6795e92008-07-17 15:21:29 -07001320 if (!group)
1321 group = ERR_PTR(-ENOMEM);
1322 if (!IS_ERR(group)) {
Joel Becker7063fbf2005-12-15 14:29:43 -08001323 link_group(to_config_group(parent_item), group);
1324 item = &group->cg_item;
Joel Beckera6795e92008-07-17 15:21:29 -07001325 } else
1326 ret = PTR_ERR(group);
Joel Becker7063fbf2005-12-15 14:29:43 -08001327 } else {
Joel Beckerf89ab862008-07-17 14:53:48 -07001328 item = type->ct_group_ops->make_item(to_config_group(parent_item), name);
Joel Beckera6795e92008-07-17 15:21:29 -07001329 if (!item)
1330 item = ERR_PTR(-ENOMEM);
1331 if (!IS_ERR(item))
Joel Becker7063fbf2005-12-15 14:29:43 -08001332 link_obj(parent_item, item);
Joel Beckera6795e92008-07-17 15:21:29 -07001333 else
1334 ret = PTR_ERR(item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001335 }
Joel Beckere6bd07a2007-07-06 23:33:17 -07001336 mutex_unlock(&subsys->su_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001337
1338 kfree(name);
Joel Beckera6795e92008-07-17 15:21:29 -07001339 if (ret) {
Joel Beckereed7a0d2006-04-11 21:37:20 -07001340 /*
Joel Beckerdacdd0e2008-07-17 16:54:19 -07001341 * If ret != 0, then link_obj() was never called.
Joel Beckereed7a0d2006-04-11 21:37:20 -07001342 * There are no extra references to clean up.
1343 */
Joel Becker70526b62008-06-17 15:34:32 -07001344 goto out_subsys_put;
Joel Becker7063fbf2005-12-15 14:29:43 -08001345 }
1346
Joel Beckereed7a0d2006-04-11 21:37:20 -07001347 /*
1348 * link_obj() has been called (via link_group() for groups).
1349 * From here on out, errors must clean that up.
1350 */
1351
Joel Becker7063fbf2005-12-15 14:29:43 -08001352 type = item->ci_type;
Joel Beckereed7a0d2006-04-11 21:37:20 -07001353 if (!type) {
1354 ret = -EINVAL;
1355 goto out_unlink;
1356 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001357
Joel Becker70526b62008-06-17 15:34:32 -07001358 new_item_owner = type->ct_owner;
1359 if (!try_module_get(new_item_owner)) {
Joel Beckereed7a0d2006-04-11 21:37:20 -07001360 ret = -EINVAL;
1361 goto out_unlink;
1362 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001363
Joel Beckereed7a0d2006-04-11 21:37:20 -07001364 /*
1365 * I hate doing it this way, but if there is
1366 * an error, module_put() probably should
1367 * happen after any cleanup.
1368 */
1369 module_got = 1;
1370
Louis Rilling6d8344b2008-06-16 19:01:02 +02001371 /*
1372 * Make racing rmdir() fail if it did not tag parent with
1373 * CONFIGFS_USET_DROPPING
1374 * Note: if CONFIGFS_USET_DROPPING is already set, attach_group() will
1375 * fail and let rmdir() terminate correctly
1376 */
1377 spin_lock(&configfs_dirent_lock);
1378 /* This will make configfs_detach_prep() fail */
1379 sd->s_type |= CONFIGFS_USET_IN_MKDIR;
1380 spin_unlock(&configfs_dirent_lock);
1381
Joel Beckereed7a0d2006-04-11 21:37:20 -07001382 if (group)
1383 ret = configfs_attach_group(parent_item, item, dentry);
1384 else
1385 ret = configfs_attach_item(parent_item, item, dentry);
1386
Louis Rilling6d8344b2008-06-16 19:01:02 +02001387 spin_lock(&configfs_dirent_lock);
1388 sd->s_type &= ~CONFIGFS_USET_IN_MKDIR;
Louis Rilling2a109f22008-07-04 16:56:05 +02001389 if (!ret)
1390 configfs_dir_set_ready(dentry->d_fsdata);
Louis Rilling6d8344b2008-06-16 19:01:02 +02001391 spin_unlock(&configfs_dirent_lock);
1392
Joel Beckereed7a0d2006-04-11 21:37:20 -07001393out_unlink:
1394 if (ret) {
1395 /* Tear down everything we built up */
Joel Beckere6bd07a2007-07-06 23:33:17 -07001396 mutex_lock(&subsys->su_mutex);
Joel Becker299894c2006-10-06 17:33:23 -07001397
1398 client_disconnect_notify(parent_item, item);
Joel Beckereed7a0d2006-04-11 21:37:20 -07001399 if (group)
1400 unlink_group(group);
1401 else
1402 unlink_obj(item);
1403 client_drop_item(parent_item, item);
Joel Becker299894c2006-10-06 17:33:23 -07001404
Joel Beckere6bd07a2007-07-06 23:33:17 -07001405 mutex_unlock(&subsys->su_mutex);
Joel Beckereed7a0d2006-04-11 21:37:20 -07001406
1407 if (module_got)
Joel Becker70526b62008-06-17 15:34:32 -07001408 module_put(new_item_owner);
Joel Becker7063fbf2005-12-15 14:29:43 -08001409 }
1410
Joel Becker70526b62008-06-17 15:34:32 -07001411out_subsys_put:
1412 if (ret)
1413 module_put(subsys_owner);
1414
Joel Becker84efad12006-03-27 18:46:09 -08001415out_put:
1416 /*
Joel Beckereed7a0d2006-04-11 21:37:20 -07001417 * link_obj()/link_group() took a reference from child->parent,
1418 * so the parent is safely pinned. We can drop our working
1419 * reference.
Joel Becker84efad12006-03-27 18:46:09 -08001420 */
1421 config_item_put(parent_item);
1422
1423out:
Joel Becker7063fbf2005-12-15 14:29:43 -08001424 return ret;
1425}
1426
1427static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
1428{
1429 struct config_item *parent_item;
1430 struct config_item *item;
1431 struct configfs_subsystem *subsys;
1432 struct configfs_dirent *sd;
Joel Becker70526b62008-06-17 15:34:32 -07001433 struct module *subsys_owner = NULL, *dead_item_owner = NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -08001434 int ret;
1435
Joel Becker7063fbf2005-12-15 14:29:43 -08001436 sd = dentry->d_fsdata;
1437 if (sd->s_type & CONFIGFS_USET_DEFAULT)
1438 return -EPERM;
1439
Joel Becker84efad12006-03-27 18:46:09 -08001440 /* Get a working ref until we have the child */
Joel Becker7063fbf2005-12-15 14:29:43 -08001441 parent_item = configfs_get_config_item(dentry->d_parent);
1442 subsys = to_config_group(parent_item)->cg_subsys;
1443 BUG_ON(!subsys);
1444
1445 if (!parent_item->ci_type) {
1446 config_item_put(parent_item);
1447 return -EINVAL;
1448 }
1449
Joel Becker70526b62008-06-17 15:34:32 -07001450 /* configfs_mkdir() shouldn't have allowed this */
1451 BUG_ON(!subsys->su_group.cg_item.ci_type);
1452 subsys_owner = subsys->su_group.cg_item.ci_type->ct_owner;
1453
Louis Rilling9a73d782008-06-20 14:09:22 +02001454 /*
1455 * Ensure that no racing symlink() will make detach_prep() fail while
1456 * the new link is temporarily attached
1457 */
Louis Rilling6d8344b2008-06-16 19:01:02 +02001458 do {
Al Viro48f35b72016-04-12 00:37:59 -04001459 struct dentry *wait;
Louis Rilling6d8344b2008-06-16 19:01:02 +02001460
Louis Rillingde6bf182008-08-15 12:37:23 -07001461 mutex_lock(&configfs_symlink_mutex);
1462 spin_lock(&configfs_dirent_lock);
Louis Rilling420118c2009-01-28 19:18:33 +01001463 /*
1464 * Here's where we check for dependents. We're protected by
1465 * configfs_dirent_lock.
1466 * If no dependent, atomically tag the item as dropping.
1467 */
1468 ret = sd->s_dependent_count ? -EBUSY : 0;
1469 if (!ret) {
Al Viro48f35b72016-04-12 00:37:59 -04001470 ret = configfs_detach_prep(dentry, &wait);
Louis Rilling420118c2009-01-28 19:18:33 +01001471 if (ret)
1472 configfs_detach_rollback(dentry);
1473 }
Louis Rillingde6bf182008-08-15 12:37:23 -07001474 spin_unlock(&configfs_dirent_lock);
1475 mutex_unlock(&configfs_symlink_mutex);
1476
1477 if (ret) {
Louis Rilling6d8344b2008-06-16 19:01:02 +02001478 if (ret != -EAGAIN) {
1479 config_item_put(parent_item);
1480 return ret;
1481 }
1482
1483 /* Wait until the racing operation terminates */
Al Viro48f35b72016-04-12 00:37:59 -04001484 inode_lock(d_inode(wait));
1485 inode_unlock(d_inode(wait));
1486 dput(wait);
Louis Rilling6d8344b2008-06-16 19:01:02 +02001487 }
1488 } while (ret == -EAGAIN);
Joel Becker7063fbf2005-12-15 14:29:43 -08001489
Joel Becker84efad12006-03-27 18:46:09 -08001490 /* Get a working ref for the duration of this function */
Joel Becker7063fbf2005-12-15 14:29:43 -08001491 item = configfs_get_config_item(dentry);
1492
1493 /* Drop reference from above, item already holds one. */
1494 config_item_put(parent_item);
1495
1496 if (item->ci_type)
Joel Becker70526b62008-06-17 15:34:32 -07001497 dead_item_owner = item->ci_type->ct_owner;
Joel Becker7063fbf2005-12-15 14:29:43 -08001498
1499 if (sd->s_type & CONFIGFS_USET_DIR) {
1500 configfs_detach_group(item);
1501
Joel Beckere6bd07a2007-07-06 23:33:17 -07001502 mutex_lock(&subsys->su_mutex);
Joel Becker299894c2006-10-06 17:33:23 -07001503 client_disconnect_notify(parent_item, item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001504 unlink_group(to_config_group(item));
1505 } else {
1506 configfs_detach_item(item);
1507
Joel Beckere6bd07a2007-07-06 23:33:17 -07001508 mutex_lock(&subsys->su_mutex);
Joel Becker299894c2006-10-06 17:33:23 -07001509 client_disconnect_notify(parent_item, item);
Joel Becker7063fbf2005-12-15 14:29:43 -08001510 unlink_obj(item);
1511 }
1512
1513 client_drop_item(parent_item, item);
Joel Beckere6bd07a2007-07-06 23:33:17 -07001514 mutex_unlock(&subsys->su_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001515
1516 /* Drop our reference from above */
1517 config_item_put(item);
1518
Joel Becker70526b62008-06-17 15:34:32 -07001519 module_put(dead_item_owner);
1520 module_put(subsys_owner);
Joel Becker7063fbf2005-12-15 14:29:43 -08001521
1522 return 0;
1523}
1524
Arjan van de Ven754661f2007-02-12 00:55:38 -08001525const struct inode_operations configfs_dir_inode_operations = {
Joel Becker7063fbf2005-12-15 14:29:43 -08001526 .mkdir = configfs_mkdir,
1527 .rmdir = configfs_rmdir,
1528 .symlink = configfs_symlink,
1529 .unlink = configfs_unlink,
1530 .lookup = configfs_lookup,
Joel Becker3d0f89b2006-01-25 13:31:07 -08001531 .setattr = configfs_setattr,
Joel Becker7063fbf2005-12-15 14:29:43 -08001532};
1533
Al Viro81d44ed12012-03-17 16:13:25 -04001534const struct inode_operations configfs_root_inode_operations = {
1535 .lookup = configfs_lookup,
1536 .setattr = configfs_setattr,
1537};
1538
Joel Becker7063fbf2005-12-15 14:29:43 -08001539#if 0
1540int configfs_rename_dir(struct config_item * item, const char *new_name)
1541{
1542 int error = 0;
1543 struct dentry * new_dentry, * parent;
1544
1545 if (!strcmp(config_item_name(item), new_name))
1546 return -EINVAL;
1547
1548 if (!item->parent)
1549 return -EINVAL;
1550
1551 down_write(&configfs_rename_sem);
1552 parent = item->parent->dentry;
1553
Al Viro59551022016-01-22 15:40:57 -05001554 inode_lock(d_inode(parent));
Joel Becker7063fbf2005-12-15 14:29:43 -08001555
1556 new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
1557 if (!IS_ERR(new_dentry)) {
David Howells2b0143b2015-03-17 22:25:59 +00001558 if (d_really_is_negative(new_dentry)) {
Joel Becker7063fbf2005-12-15 14:29:43 -08001559 error = config_item_set_name(item, "%s", new_name);
1560 if (!error) {
1561 d_add(new_dentry, NULL);
1562 d_move(item->dentry, new_dentry);
1563 }
1564 else
1565 d_delete(new_dentry);
1566 } else
1567 error = -EEXIST;
1568 dput(new_dentry);
1569 }
Al Viro59551022016-01-22 15:40:57 -05001570 inode_unlock(d_inode(parent));
Joel Becker7063fbf2005-12-15 14:29:43 -08001571 up_write(&configfs_rename_sem);
1572
1573 return error;
1574}
1575#endif
1576
1577static int configfs_dir_open(struct inode *inode, struct file *file)
1578{
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001579 struct dentry * dentry = file->f_path.dentry;
Joel Becker7063fbf2005-12-15 14:29:43 -08001580 struct configfs_dirent * parent_sd = dentry->d_fsdata;
Louis Rilling2a109f22008-07-04 16:56:05 +02001581 int err;
Joel Becker7063fbf2005-12-15 14:29:43 -08001582
Al Viro59551022016-01-22 15:40:57 -05001583 inode_lock(d_inode(dentry));
Louis Rilling2a109f22008-07-04 16:56:05 +02001584 /*
1585 * Fake invisibility if dir belongs to a group/default groups hierarchy
1586 * being attached
1587 */
1588 err = -ENOENT;
1589 if (configfs_dirent_is_ready(parent_sd)) {
Louis Rilling420118c2009-01-28 19:18:33 +01001590 file->private_data = configfs_new_dirent(parent_sd, NULL, 0);
Louis Rilling2a109f22008-07-04 16:56:05 +02001591 if (IS_ERR(file->private_data))
1592 err = PTR_ERR(file->private_data);
1593 else
1594 err = 0;
1595 }
Al Viro59551022016-01-22 15:40:57 -05001596 inode_unlock(d_inode(dentry));
Joel Becker7063fbf2005-12-15 14:29:43 -08001597
Louis Rilling2a109f22008-07-04 16:56:05 +02001598 return err;
Joel Becker7063fbf2005-12-15 14:29:43 -08001599}
1600
1601static int configfs_dir_close(struct inode *inode, struct file *file)
1602{
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001603 struct dentry * dentry = file->f_path.dentry;
Joel Becker7063fbf2005-12-15 14:29:43 -08001604 struct configfs_dirent * cursor = file->private_data;
1605
Al Viro59551022016-01-22 15:40:57 -05001606 inode_lock(d_inode(dentry));
Louis Rilling6f610762008-06-16 19:00:58 +02001607 spin_lock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -08001608 list_del_init(&cursor->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +02001609 spin_unlock(&configfs_dirent_lock);
Al Viro59551022016-01-22 15:40:57 -05001610 inode_unlock(d_inode(dentry));
Joel Becker7063fbf2005-12-15 14:29:43 -08001611
1612 release_configfs_dirent(cursor);
1613
1614 return 0;
1615}
1616
1617/* Relationship between s_mode and the DT_xxx types */
1618static inline unsigned char dt_type(struct configfs_dirent *sd)
1619{
1620 return (sd->s_mode >> 12) & 15;
1621}
1622
Al Viro52018852013-05-16 01:28:34 -04001623static int configfs_readdir(struct file *file, struct dir_context *ctx)
Joel Becker7063fbf2005-12-15 14:29:43 -08001624{
Al Viro52018852013-05-16 01:28:34 -04001625 struct dentry *dentry = file->f_path.dentry;
Al Virob7c177f2012-03-17 16:24:54 -04001626 struct super_block *sb = dentry->d_sb;
Joel Becker7063fbf2005-12-15 14:29:43 -08001627 struct configfs_dirent * parent_sd = dentry->d_fsdata;
Al Viro52018852013-05-16 01:28:34 -04001628 struct configfs_dirent *cursor = file->private_data;
Joel Becker7063fbf2005-12-15 14:29:43 -08001629 struct list_head *p, *q = &cursor->s_sibling;
Joel Becker24307aa2011-05-18 04:08:16 -07001630 ino_t ino = 0;
Joel Becker7063fbf2005-12-15 14:29:43 -08001631
Al Viro52018852013-05-16 01:28:34 -04001632 if (!dir_emit_dots(file, ctx))
1633 return 0;
Al Viroa01b3002016-04-20 19:50:05 -04001634 spin_lock(&configfs_dirent_lock);
1635 if (ctx->pos == 2)
Al Viro52018852013-05-16 01:28:34 -04001636 list_move(q, &parent_sd->s_children);
Al Viro52018852013-05-16 01:28:34 -04001637 for (p = q->next; p != &parent_sd->s_children; p = p->next) {
1638 struct configfs_dirent *next;
1639 const char *name;
1640 int len;
1641 struct inode *inode = NULL;
Joel Becker7063fbf2005-12-15 14:29:43 -08001642
Al Viro52018852013-05-16 01:28:34 -04001643 next = list_entry(p, struct configfs_dirent, s_sibling);
1644 if (!next->s_element)
1645 continue;
Joel Becker7063fbf2005-12-15 14:29:43 -08001646
Al Viro52018852013-05-16 01:28:34 -04001647 /*
1648 * We'll have a dentry and an inode for
1649 * PINNED items and for open attribute
1650 * files. We lock here to prevent a race
1651 * with configfs_d_iput() clearing
1652 * s_dentry before calling iput().
1653 *
1654 * Why do we go to the trouble? If
1655 * someone has an attribute file open,
1656 * the inode number should match until
1657 * they close it. Beyond that, we don't
1658 * care.
1659 */
Al Viro52018852013-05-16 01:28:34 -04001660 dentry = next->s_dentry;
1661 if (dentry)
David Howells2b0143b2015-03-17 22:25:59 +00001662 inode = d_inode(dentry);
Al Viro52018852013-05-16 01:28:34 -04001663 if (inode)
1664 ino = inode->i_ino;
1665 spin_unlock(&configfs_dirent_lock);
1666 if (!inode)
1667 ino = iunique(sb, 2);
Joel Becker7063fbf2005-12-15 14:29:43 -08001668
Al Viroa01b3002016-04-20 19:50:05 -04001669 name = configfs_get_name(next);
1670 len = strlen(name);
1671
Al Viro52018852013-05-16 01:28:34 -04001672 if (!dir_emit(ctx, name, len, ino, dt_type(next)))
1673 return 0;
Joel Becker7063fbf2005-12-15 14:29:43 -08001674
Al Viro52018852013-05-16 01:28:34 -04001675 spin_lock(&configfs_dirent_lock);
1676 list_move(q, p);
Al Viro52018852013-05-16 01:28:34 -04001677 p = q;
1678 ctx->pos++;
Joel Becker7063fbf2005-12-15 14:29:43 -08001679 }
Al Viroa01b3002016-04-20 19:50:05 -04001680 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -08001681 return 0;
1682}
1683
Andrew Morton965c8e52012-12-17 15:59:39 -08001684static loff_t configfs_dir_lseek(struct file *file, loff_t offset, int whence)
Joel Becker7063fbf2005-12-15 14:29:43 -08001685{
Josef "Jeff" Sipek867fa492006-12-08 02:36:47 -08001686 struct dentry * dentry = file->f_path.dentry;
Joel Becker7063fbf2005-12-15 14:29:43 -08001687
Andrew Morton965c8e52012-12-17 15:59:39 -08001688 switch (whence) {
Joel Becker7063fbf2005-12-15 14:29:43 -08001689 case 1:
1690 offset += file->f_pos;
1691 case 0:
1692 if (offset >= 0)
1693 break;
1694 default:
Joel Becker7063fbf2005-12-15 14:29:43 -08001695 return -EINVAL;
1696 }
1697 if (offset != file->f_pos) {
1698 file->f_pos = offset;
1699 if (file->f_pos >= 2) {
1700 struct configfs_dirent *sd = dentry->d_fsdata;
1701 struct configfs_dirent *cursor = file->private_data;
1702 struct list_head *p;
1703 loff_t n = file->f_pos - 2;
1704
Louis Rilling6f610762008-06-16 19:00:58 +02001705 spin_lock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -08001706 list_del(&cursor->s_sibling);
1707 p = sd->s_children.next;
1708 while (n && p != &sd->s_children) {
1709 struct configfs_dirent *next;
1710 next = list_entry(p, struct configfs_dirent,
1711 s_sibling);
1712 if (next->s_element)
1713 n--;
1714 p = p->next;
1715 }
1716 list_add_tail(&cursor->s_sibling, p);
Louis Rilling6f610762008-06-16 19:00:58 +02001717 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -08001718 }
1719 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001720 return offset;
1721}
1722
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -08001723const struct file_operations configfs_dir_operations = {
Joel Becker7063fbf2005-12-15 14:29:43 -08001724 .open = configfs_dir_open,
1725 .release = configfs_dir_close,
1726 .llseek = configfs_dir_lseek,
1727 .read = generic_read_dir,
Al Viroa01b3002016-04-20 19:50:05 -04001728 .iterate_shared = configfs_readdir,
Joel Becker7063fbf2005-12-15 14:29:43 -08001729};
1730
Daniel Baluta5cf6a512015-11-20 15:56:53 -08001731/**
1732 * configfs_register_group - creates a parent-child relation between two groups
1733 * @parent_group: parent group
1734 * @group: child group
1735 *
1736 * link groups, creates dentry for the child and attaches it to the
1737 * parent dentry.
1738 *
1739 * Return: 0 on success, negative errno code on error
1740 */
1741int configfs_register_group(struct config_group *parent_group,
1742 struct config_group *group)
1743{
1744 struct configfs_subsystem *subsys = parent_group->cg_subsys;
1745 struct dentry *parent;
1746 int ret;
1747
1748 mutex_lock(&subsys->su_mutex);
1749 link_group(parent_group, group);
1750 mutex_unlock(&subsys->su_mutex);
1751
1752 parent = parent_group->cg_item.ci_dentry;
1753
Al Viro59551022016-01-22 15:40:57 -05001754 inode_lock_nested(d_inode(parent), I_MUTEX_PARENT);
Daniel Baluta5cf6a512015-11-20 15:56:53 -08001755 ret = create_default_group(parent_group, group);
YueHaibinga4681102019-05-05 11:03:12 +08001756 if (ret)
1757 goto err_out;
1758
1759 spin_lock(&configfs_dirent_lock);
1760 configfs_dir_set_ready(group->cg_item.ci_dentry->d_fsdata);
1761 spin_unlock(&configfs_dirent_lock);
Al Viro59551022016-01-22 15:40:57 -05001762 inode_unlock(d_inode(parent));
YueHaibinga4681102019-05-05 11:03:12 +08001763 return 0;
1764err_out:
1765 inode_unlock(d_inode(parent));
1766 mutex_lock(&subsys->su_mutex);
1767 unlink_group(group);
1768 mutex_unlock(&subsys->su_mutex);
Daniel Baluta5cf6a512015-11-20 15:56:53 -08001769 return ret;
1770}
1771EXPORT_SYMBOL(configfs_register_group);
1772
1773/**
1774 * configfs_unregister_group() - unregisters a child group from its parent
1775 * @group: parent group to be unregistered
1776 *
1777 * Undoes configfs_register_group()
1778 */
1779void configfs_unregister_group(struct config_group *group)
1780{
1781 struct configfs_subsystem *subsys = group->cg_subsys;
1782 struct dentry *dentry = group->cg_item.ci_dentry;
1783 struct dentry *parent = group->cg_item.ci_parent->ci_dentry;
1784
Mike Christie5e790d72018-07-15 18:16:17 -05001785 mutex_lock(&subsys->su_mutex);
1786 if (!group->cg_item.ci_parent->ci_group) {
1787 /*
1788 * The parent has already been unlinked and detached
1789 * due to a rmdir.
1790 */
1791 goto unlink_group;
1792 }
1793 mutex_unlock(&subsys->su_mutex);
1794
Al Viro59551022016-01-22 15:40:57 -05001795 inode_lock_nested(d_inode(parent), I_MUTEX_PARENT);
Daniel Baluta5cf6a512015-11-20 15:56:53 -08001796 spin_lock(&configfs_dirent_lock);
1797 configfs_detach_prep(dentry, NULL);
1798 spin_unlock(&configfs_dirent_lock);
1799
1800 configfs_detach_group(&group->cg_item);
1801 d_inode(dentry)->i_flags |= S_DEAD;
1802 dont_mount(dentry);
1803 d_delete(dentry);
Al Viro59551022016-01-22 15:40:57 -05001804 inode_unlock(d_inode(parent));
Daniel Baluta5cf6a512015-11-20 15:56:53 -08001805
1806 dput(dentry);
1807
1808 mutex_lock(&subsys->su_mutex);
Mike Christie5e790d72018-07-15 18:16:17 -05001809unlink_group:
Daniel Baluta5cf6a512015-11-20 15:56:53 -08001810 unlink_group(group);
1811 mutex_unlock(&subsys->su_mutex);
1812}
1813EXPORT_SYMBOL(configfs_unregister_group);
1814
1815/**
1816 * configfs_register_default_group() - allocates and registers a child group
1817 * @parent_group: parent group
1818 * @name: child group name
1819 * @item_type: child item type description
1820 *
1821 * boilerplate to allocate and register a child group with its parent. We need
1822 * kzalloc'ed memory because child's default_group is initially empty.
1823 *
1824 * Return: allocated config group or ERR_PTR() on error
1825 */
1826struct config_group *
1827configfs_register_default_group(struct config_group *parent_group,
1828 const char *name,
1829 struct config_item_type *item_type)
1830{
1831 int ret;
1832 struct config_group *group;
1833
1834 group = kzalloc(sizeof(*group), GFP_KERNEL);
1835 if (!group)
1836 return ERR_PTR(-ENOMEM);
1837 config_group_init_type_name(group, name, item_type);
1838
1839 ret = configfs_register_group(parent_group, group);
1840 if (ret) {
1841 kfree(group);
1842 return ERR_PTR(ret);
1843 }
1844 return group;
1845}
1846EXPORT_SYMBOL(configfs_register_default_group);
1847
1848/**
1849 * configfs_unregister_default_group() - unregisters and frees a child group
1850 * @group: the group to act on
1851 */
1852void configfs_unregister_default_group(struct config_group *group)
1853{
1854 configfs_unregister_group(group);
1855 kfree(group);
1856}
1857EXPORT_SYMBOL(configfs_unregister_default_group);
1858
Joel Becker7063fbf2005-12-15 14:29:43 -08001859int configfs_register_subsystem(struct configfs_subsystem *subsys)
1860{
1861 int err;
1862 struct config_group *group = &subsys->su_group;
Joel Becker7063fbf2005-12-15 14:29:43 -08001863 struct dentry *dentry;
Al Virob7c177f2012-03-17 16:24:54 -04001864 struct dentry *root;
Joel Becker7063fbf2005-12-15 14:29:43 -08001865 struct configfs_dirent *sd;
1866
Al Viro2a152ad2012-03-17 16:53:29 -04001867 root = configfs_pin_fs();
1868 if (IS_ERR(root))
1869 return PTR_ERR(root);
Joel Becker7063fbf2005-12-15 14:29:43 -08001870
1871 if (!group->cg_item.ci_name)
1872 group->cg_item.ci_name = group->cg_item.ci_namebuf;
1873
Al Virob7c177f2012-03-17 16:24:54 -04001874 sd = root->d_fsdata;
Joel Becker7063fbf2005-12-15 14:29:43 -08001875 link_group(to_config_group(sd->s_element), group);
1876
Al Viro59551022016-01-22 15:40:57 -05001877 inode_lock_nested(d_inode(root), I_MUTEX_PARENT);
Joel Becker7063fbf2005-12-15 14:29:43 -08001878
Joel Becker7063fbf2005-12-15 14:29:43 -08001879 err = -ENOMEM;
Al Viroec193cf2013-07-14 17:16:52 +04001880 dentry = d_alloc_name(root, group->cg_item.ci_name);
Joel Beckerafdf04e2007-03-05 15:49:49 -08001881 if (dentry) {
1882 d_add(dentry, NULL);
Joel Becker7063fbf2005-12-15 14:29:43 -08001883
Joel Beckerafdf04e2007-03-05 15:49:49 -08001884 err = configfs_attach_group(sd->s_element, &group->cg_item,
1885 dentry);
1886 if (err) {
David Howells2b0143b2015-03-17 22:25:59 +00001887 BUG_ON(d_inode(dentry));
Joel Beckerdf7f9962011-02-22 01:09:49 -08001888 d_drop(dentry);
Joel Beckerafdf04e2007-03-05 15:49:49 -08001889 dput(dentry);
Louis Rilling2a109f22008-07-04 16:56:05 +02001890 } else {
1891 spin_lock(&configfs_dirent_lock);
1892 configfs_dir_set_ready(dentry->d_fsdata);
1893 spin_unlock(&configfs_dirent_lock);
Joel Beckerafdf04e2007-03-05 15:49:49 -08001894 }
1895 }
Joel Becker7063fbf2005-12-15 14:29:43 -08001896
Al Viro59551022016-01-22 15:40:57 -05001897 inode_unlock(d_inode(root));
Joel Becker7063fbf2005-12-15 14:29:43 -08001898
Joel Beckerafdf04e2007-03-05 15:49:49 -08001899 if (err) {
1900 unlink_group(group);
1901 configfs_release_fs();
Joel Becker7063fbf2005-12-15 14:29:43 -08001902 }
1903
1904 return err;
1905}
1906
1907void configfs_unregister_subsystem(struct configfs_subsystem *subsys)
1908{
1909 struct config_group *group = &subsys->su_group;
1910 struct dentry *dentry = group->cg_item.ci_dentry;
Al Virob7c177f2012-03-17 16:24:54 -04001911 struct dentry *root = dentry->d_sb->s_root;
Joel Becker7063fbf2005-12-15 14:29:43 -08001912
Al Virob7c177f2012-03-17 16:24:54 -04001913 if (dentry->d_parent != root) {
Fabian Frederick1d88aa42014-06-04 16:05:59 -07001914 pr_err("Tried to unregister non-subsystem!\n");
Joel Becker7063fbf2005-12-15 14:29:43 -08001915 return;
1916 }
1917
Al Viro59551022016-01-22 15:40:57 -05001918 inode_lock_nested(d_inode(root),
Mark Fasheh55ed1602006-10-20 14:55:54 -07001919 I_MUTEX_PARENT);
Al Viro59551022016-01-22 15:40:57 -05001920 inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);
Louis Rilling9a73d782008-06-20 14:09:22 +02001921 mutex_lock(&configfs_symlink_mutex);
Louis Rillingb3e76af2008-06-16 19:01:01 +02001922 spin_lock(&configfs_dirent_lock);
Louis Rilling6d8344b2008-06-16 19:01:02 +02001923 if (configfs_detach_prep(dentry, NULL)) {
Fabian Frederick1d88aa42014-06-04 16:05:59 -07001924 pr_err("Tried to unregister non-empty subsystem!\n");
Joel Becker7063fbf2005-12-15 14:29:43 -08001925 }
Louis Rillingb3e76af2008-06-16 19:01:01 +02001926 spin_unlock(&configfs_dirent_lock);
Louis Rilling9a73d782008-06-20 14:09:22 +02001927 mutex_unlock(&configfs_symlink_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -08001928 configfs_detach_group(&group->cg_item);
David Howells2b0143b2015-03-17 22:25:59 +00001929 d_inode(dentry)->i_flags |= S_DEAD;
Al Virod83c49f2010-04-30 17:17:09 -04001930 dont_mount(dentry);
Al Viro59551022016-01-22 15:40:57 -05001931 inode_unlock(d_inode(dentry));
Joel Becker7063fbf2005-12-15 14:29:43 -08001932
1933 d_delete(dentry);
1934
Al Viro59551022016-01-22 15:40:57 -05001935 inode_unlock(d_inode(root));
Joel Becker7063fbf2005-12-15 14:29:43 -08001936
1937 dput(dentry);
1938
1939 unlink_group(group);
1940 configfs_release_fs();
1941}
1942
1943EXPORT_SYMBOL(configfs_register_subsystem);
1944EXPORT_SYMBOL(configfs_unregister_subsystem);