blob: fbb30db0fce7073ab247474bb99584ce4196903a [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 * inode.c - basic inode and dentry operations.
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 *
Paul Bolle395cf962011-08-15 02:02:26 +020026 * Please see Documentation/filesystems/configfs/configfs.txt for more
27 * information.
Joel Becker7063fbf2005-12-15 14:29:43 -080028 */
29
30#undef DEBUG
31
32#include <linux/pagemap.h>
33#include <linux/namei.h>
34#include <linux/backing-dev.h>
Joel Becker3d0f89b2006-01-25 13:31:07 -080035#include <linux/capability.h>
Alexey Dobriyane8edc6e2007-05-21 01:22:52 +040036#include <linux/sched.h>
Louis Rillinge74cc062009-01-28 19:18:32 +010037#include <linux/lockdep.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090038#include <linux/slab.h>
Joel Becker7063fbf2005-12-15 14:29:43 -080039
40#include <linux/configfs.h>
41#include "configfs_internal.h"
42
Louis Rillinge74cc062009-01-28 19:18:32 +010043#ifdef CONFIG_LOCKDEP
44static struct lock_class_key default_group_class[MAX_LOCK_DEPTH];
45#endif
46
Christoph Hellwigf5e54d62006-06-28 04:26:44 -070047static const struct address_space_operations configfs_aops = {
Joel Becker7063fbf2005-12-15 14:29:43 -080048 .readpage = simple_readpage,
Nick Piggin800d15a2007-10-16 01:25:03 -070049 .write_begin = simple_write_begin,
50 .write_end = simple_write_end,
Joel Becker7063fbf2005-12-15 14:29:43 -080051};
52
53static struct backing_dev_info configfs_backing_dev_info = {
Jens Axboed9938312009-06-12 14:45:52 +020054 .name = "configfs",
Joel Becker7063fbf2005-12-15 14:29:43 -080055 .ra_pages = 0, /* No readahead */
Miklos Szeredie4ad08f2008-04-30 00:54:37 -070056 .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
Joel Becker7063fbf2005-12-15 14:29:43 -080057};
58
Arjan van de Ven754661f2007-02-12 00:55:38 -080059static const struct inode_operations configfs_inode_operations ={
Joel Becker3d0f89b2006-01-25 13:31:07 -080060 .setattr = configfs_setattr,
61};
62
63int configfs_setattr(struct dentry * dentry, struct iattr * iattr)
64{
65 struct inode * inode = dentry->d_inode;
66 struct configfs_dirent * sd = dentry->d_fsdata;
67 struct iattr * sd_iattr;
68 unsigned int ia_valid = iattr->ia_valid;
69 int error;
70
71 if (!sd)
72 return -EINVAL;
73
74 sd_iattr = sd->s_iattr;
Joel Becker3d0f89b2006-01-25 13:31:07 -080075 if (!sd_iattr) {
76 /* setting attributes for the first time, allocate now */
Panagiotis Issarisf8314dc2006-09-27 01:49:37 -070077 sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL);
Joel Becker3d0f89b2006-01-25 13:31:07 -080078 if (!sd_iattr)
79 return -ENOMEM;
80 /* assign default attributes */
Joel Becker3d0f89b2006-01-25 13:31:07 -080081 sd_iattr->ia_mode = sd->s_mode;
Eric W. Biederman69552c02012-02-07 16:28:09 -080082 sd_iattr->ia_uid = GLOBAL_ROOT_UID;
83 sd_iattr->ia_gid = GLOBAL_ROOT_GID;
Joel Becker3d0f89b2006-01-25 13:31:07 -080084 sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime = CURRENT_TIME;
85 sd->s_iattr = sd_iattr;
86 }
Joel Becker3d0f89b2006-01-25 13:31:07 -080087 /* attributes were changed atleast once in past */
88
Nick Piggin75de46b2010-05-31 17:58:02 +100089 error = simple_setattr(dentry, iattr);
90 if (error)
91 return error;
92
Joel Becker3d0f89b2006-01-25 13:31:07 -080093 if (ia_valid & ATTR_UID)
94 sd_iattr->ia_uid = iattr->ia_uid;
95 if (ia_valid & ATTR_GID)
96 sd_iattr->ia_gid = iattr->ia_gid;
97 if (ia_valid & ATTR_ATIME)
98 sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime,
99 inode->i_sb->s_time_gran);
100 if (ia_valid & ATTR_MTIME)
101 sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime,
102 inode->i_sb->s_time_gran);
103 if (ia_valid & ATTR_CTIME)
104 sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime,
105 inode->i_sb->s_time_gran);
106 if (ia_valid & ATTR_MODE) {
107 umode_t mode = iattr->ia_mode;
108
109 if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
110 mode &= ~S_ISGID;
111 sd_iattr->ia_mode = sd->s_mode = mode;
112 }
113
114 return error;
115}
116
Al Viro43947512011-07-25 00:05:26 -0400117static inline void set_default_inode_attr(struct inode * inode, umode_t mode)
Joel Becker3d0f89b2006-01-25 13:31:07 -0800118{
119 inode->i_mode = mode;
Joel Becker3d0f89b2006-01-25 13:31:07 -0800120 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
121}
122
123static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
124{
125 inode->i_mode = iattr->ia_mode;
126 inode->i_uid = iattr->ia_uid;
127 inode->i_gid = iattr->ia_gid;
128 inode->i_atime = iattr->ia_atime;
129 inode->i_mtime = iattr->ia_mtime;
130 inode->i_ctime = iattr->ia_ctime;
131}
132
Al Virob7c177f2012-03-17 16:24:54 -0400133struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd,
134 struct super_block *s)
Joel Becker7063fbf2005-12-15 14:29:43 -0800135{
Al Virob7c177f2012-03-17 16:24:54 -0400136 struct inode * inode = new_inode(s);
Joel Becker7063fbf2005-12-15 14:29:43 -0800137 if (inode) {
Christoph Hellwig85fe4022010-10-23 11:19:54 -0400138 inode->i_ino = get_next_ino();
Joel Becker7063fbf2005-12-15 14:29:43 -0800139 inode->i_mapping->a_ops = &configfs_aops;
140 inode->i_mapping->backing_dev_info = &configfs_backing_dev_info;
Joel Becker3d0f89b2006-01-25 13:31:07 -0800141 inode->i_op = &configfs_inode_operations;
142
143 if (sd->s_iattr) {
144 /* sysfs_dirent has non-default attributes
145 * get them for the new inode from persistent copy
146 * in sysfs_dirent
147 */
148 set_inode_attr(inode, sd->s_iattr);
149 } else
150 set_default_inode_attr(inode, mode);
Joel Becker7063fbf2005-12-15 14:29:43 -0800151 }
152 return inode;
153}
154
Louis Rillinge74cc062009-01-28 19:18:32 +0100155#ifdef CONFIG_LOCKDEP
156
157static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
158 struct inode *inode)
159{
160 int depth = sd->s_depth;
161
162 if (depth > 0) {
163 if (depth <= ARRAY_SIZE(default_group_class)) {
164 lockdep_set_class(&inode->i_mutex,
165 &default_group_class[depth - 1]);
166 } else {
167 /*
168 * In practice the maximum level of locking depth is
169 * already reached. Just inform about possible reasons.
170 */
Fabian Frederickc6686932014-06-04 16:05:58 -0700171 pr_info("configfs: Too many levels of inodes for the locking correctness validator.\n");
172 pr_info("Spurious warnings may appear.\n");
Louis Rillinge74cc062009-01-28 19:18:32 +0100173 }
174 }
175}
176
177#else /* CONFIG_LOCKDEP */
178
179static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
180 struct inode *inode)
181{
182}
183
184#endif /* CONFIG_LOCKDEP */
185
Al Viro43947512011-07-25 00:05:26 -0400186int configfs_create(struct dentry * dentry, umode_t mode, int (*init)(struct inode *))
Joel Becker7063fbf2005-12-15 14:29:43 -0800187{
188 int error = 0;
Al Viro16d13b52012-03-17 16:41:55 -0400189 struct inode *inode = NULL;
190 struct configfs_dirent *sd;
191 struct inode *p_inode;
Joel Becker7063fbf2005-12-15 14:29:43 -0800192
Al Viro16d13b52012-03-17 16:41:55 -0400193 if (!dentry)
194 return -ENOENT;
195
196 if (dentry->d_inode)
197 return -EEXIST;
198
199 sd = dentry->d_fsdata;
200 inode = configfs_new_inode(mode, sd, dentry->d_sb);
201 if (!inode)
202 return -ENOMEM;
203
204 p_inode = dentry->d_parent->d_inode;
205 p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME;
206 configfs_set_inode_lock_class(sd, inode);
207
208 if (init) {
Joel Becker7063fbf2005-12-15 14:29:43 -0800209 error = init(inode);
Al Viro16d13b52012-03-17 16:41:55 -0400210 if (error) {
211 iput(inode);
212 return error;
213 }
214 }
215 d_instantiate(dentry, inode);
216 if (S_ISDIR(mode) || S_ISLNK(mode))
217 dget(dentry); /* pin link and directory dentries in core */
Joel Becker7063fbf2005-12-15 14:29:43 -0800218 return error;
219}
220
221/*
222 * Get the name for corresponding element represented by the given configfs_dirent
223 */
224const unsigned char * configfs_get_name(struct configfs_dirent *sd)
225{
Joel Becker3d0f89b2006-01-25 13:31:07 -0800226 struct configfs_attribute *attr;
Joel Becker7063fbf2005-12-15 14:29:43 -0800227
Eric Sesterhenn / snakebyte1a1974f2006-01-27 10:32:24 +0100228 BUG_ON(!sd || !sd->s_element);
Joel Becker7063fbf2005-12-15 14:29:43 -0800229
230 /* These always have a dentry, so use that */
231 if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK))
232 return sd->s_dentry->d_name.name;
233
234 if (sd->s_type & CONFIGFS_ITEM_ATTR) {
235 attr = sd->s_element;
Joel Becker3d0f89b2006-01-25 13:31:07 -0800236 return attr->ca_name;
Joel Becker7063fbf2005-12-15 14:29:43 -0800237 }
238 return NULL;
239}
240
241
242/*
243 * Unhashes the dentry corresponding to given configfs_dirent
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800244 * Called with parent inode's i_mutex held.
Joel Becker7063fbf2005-12-15 14:29:43 -0800245 */
246void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
247{
248 struct dentry * dentry = sd->s_dentry;
249
250 if (dentry) {
Joel Becker3d0f89b2006-01-25 13:31:07 -0800251 spin_lock(&dentry->d_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800252 if (!(d_unhashed(dentry) && dentry->d_inode)) {
Nick Piggindc0474b2011-01-07 17:49:43 +1100253 dget_dlock(dentry);
Joel Becker7063fbf2005-12-15 14:29:43 -0800254 __d_drop(dentry);
Joel Becker3d0f89b2006-01-25 13:31:07 -0800255 spin_unlock(&dentry->d_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800256 simple_unlink(parent->d_inode, dentry);
Nick Pigginb5c84bf2011-01-07 17:49:38 +1100257 } else
Joel Becker3d0f89b2006-01-25 13:31:07 -0800258 spin_unlock(&dentry->d_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800259 }
260}
261
262void configfs_hash_and_remove(struct dentry * dir, const char * name)
263{
264 struct configfs_dirent * sd;
265 struct configfs_dirent * parent_sd = dir->d_fsdata;
266
Joel Becker3d0f89b2006-01-25 13:31:07 -0800267 if (dir->d_inode == NULL)
268 /* no inode means this hasn't been made visible yet */
269 return;
270
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800271 mutex_lock(&dir->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -0800272 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
273 if (!sd->s_element)
274 continue;
275 if (!strcmp(configfs_get_name(sd), name)) {
Louis Rilling6f610762008-06-16 19:00:58 +0200276 spin_lock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800277 list_del_init(&sd->s_sibling);
Louis Rilling6f610762008-06-16 19:00:58 +0200278 spin_unlock(&configfs_dirent_lock);
Joel Becker7063fbf2005-12-15 14:29:43 -0800279 configfs_drop_dentry(sd, dir);
280 configfs_put(sd);
281 break;
282 }
283 }
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800284 mutex_unlock(&dir->d_inode->i_mutex);
Joel Becker7063fbf2005-12-15 14:29:43 -0800285}
286
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -0700287int __init configfs_inode_init(void)
288{
289 return bdi_init(&configfs_backing_dev_info);
290}
Joel Becker7063fbf2005-12-15 14:29:43 -0800291
Al Viro7c6455e2011-12-13 12:32:42 -0500292void configfs_inode_exit(void)
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -0700293{
294 bdi_destroy(&configfs_backing_dev_info);
295}