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1/* -*- 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 *
26 * Please see Documentation/filesystems/configfs/configfs.txt for more
27 * information.
28 */
29
30#undef DEBUG
31
32#include <linux/pagemap.h>
33#include <linux/namei.h>
34#include <linux/backing-dev.h>
35#include <linux/capability.h>
36#include <linux/sched.h>
37#include <linux/lockdep.h>
38#include <linux/slab.h>
39
40#include <linux/configfs.h>
41#include "configfs_internal.h"
42
43#ifdef CONFIG_LOCKDEP
44static struct lock_class_key default_group_class[MAX_LOCK_DEPTH];
45#endif
46
47static const struct address_space_operations configfs_aops = {
48 .readpage = simple_readpage,
49 .write_begin = simple_write_begin,
50 .write_end = simple_write_end,
51};
52
53static struct backing_dev_info configfs_backing_dev_info = {
54 .name = "configfs",
55 .ra_pages = 0, /* No readahead */
56 .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
57};
58
59static const struct inode_operations configfs_inode_operations ={
60 .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;
75 if (!sd_iattr) {
76 /* setting attributes for the first time, allocate now */
77 sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL);
78 if (!sd_iattr)
79 return -ENOMEM;
80 /* assign default attributes */
81 sd_iattr->ia_mode = sd->s_mode;
82 sd_iattr->ia_uid = 0;
83 sd_iattr->ia_gid = 0;
84 sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime = CURRENT_TIME;
85 sd->s_iattr = sd_iattr;
86 }
87 /* attributes were changed atleast once in past */
88
89 error = simple_setattr(dentry, iattr);
90 if (error)
91 return error;
92
93 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
117static inline void set_default_inode_attr(struct inode * inode, umode_t mode)
118{
119 inode->i_mode = mode;
120 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
133struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd,
134 struct super_block *s)
135{
136 struct inode * inode = new_inode(s);
137 if (inode) {
138 inode->i_ino = get_next_ino();
139 inode->i_mapping->a_ops = &configfs_aops;
140 inode->i_mapping->backing_dev_info = &configfs_backing_dev_info;
141 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);
151 }
152 return inode;
153}
154
155#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 */
171 printk(KERN_INFO "configfs: Too many levels of inodes"
172 " for the locking correctness validator.\n");
173 printk(KERN_INFO "Spurious warnings may appear.\n");
174 }
175 }
176}
177
178#else /* CONFIG_LOCKDEP */
179
180static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
181 struct inode *inode)
182{
183}
184
185#endif /* CONFIG_LOCKDEP */
186
187int configfs_create(struct dentry * dentry, umode_t mode, int (*init)(struct inode *))
188{
189 int error = 0;
190 struct inode *inode = NULL;
191 struct configfs_dirent *sd;
192 struct inode *p_inode;
193
194 if (!dentry)
195 return -ENOENT;
196
197 if (dentry->d_inode)
198 return -EEXIST;
199
200 sd = dentry->d_fsdata;
201 inode = configfs_new_inode(mode, sd, dentry->d_sb);
202 if (!inode)
203 return -ENOMEM;
204
205 p_inode = dentry->d_parent->d_inode;
206 p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME;
207 configfs_set_inode_lock_class(sd, inode);
208
209 if (init) {
210 error = init(inode);
211 if (error) {
212 iput(inode);
213 return error;
214 }
215 }
216 d_instantiate(dentry, inode);
217 if (S_ISDIR(mode) || S_ISLNK(mode))
218 dget(dentry); /* pin link and directory dentries in core */
219 return error;
220}
221
222/*
223 * Get the name for corresponding element represented by the given configfs_dirent
224 */
225const unsigned char * configfs_get_name(struct configfs_dirent *sd)
226{
227 struct configfs_attribute *attr;
228
229 BUG_ON(!sd || !sd->s_element);
230
231 /* These always have a dentry, so use that */
232 if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK))
233 return sd->s_dentry->d_name.name;
234
235 if (sd->s_type & CONFIGFS_ITEM_ATTR) {
236 attr = sd->s_element;
237 return attr->ca_name;
238 }
239 return NULL;
240}
241
242
243/*
244 * Unhashes the dentry corresponding to given configfs_dirent
245 * Called with parent inode's i_mutex held.
246 */
247void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
248{
249 struct dentry * dentry = sd->s_dentry;
250
251 if (dentry) {
252 spin_lock(&dentry->d_lock);
253 if (!(d_unhashed(dentry) && dentry->d_inode)) {
254 dget_dlock(dentry);
255 __d_drop(dentry);
256 spin_unlock(&dentry->d_lock);
257 simple_unlink(parent->d_inode, dentry);
258 } else
259 spin_unlock(&dentry->d_lock);
260 }
261}
262
263void configfs_hash_and_remove(struct dentry * dir, const char * name)
264{
265 struct configfs_dirent * sd;
266 struct configfs_dirent * parent_sd = dir->d_fsdata;
267
268 if (dir->d_inode == NULL)
269 /* no inode means this hasn't been made visible yet */
270 return;
271
272 mutex_lock(&dir->d_inode->i_mutex);
273 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
274 if (!sd->s_element)
275 continue;
276 if (!strcmp(configfs_get_name(sd), name)) {
277 spin_lock(&configfs_dirent_lock);
278 list_del_init(&sd->s_sibling);
279 spin_unlock(&configfs_dirent_lock);
280 configfs_drop_dentry(sd, dir);
281 configfs_put(sd);
282 break;
283 }
284 }
285 mutex_unlock(&dir->d_inode->i_mutex);
286}
287
288int __init configfs_inode_init(void)
289{
290 return bdi_init(&configfs_backing_dev_info);
291}
292
293void configfs_inode_exit(void)
294{
295 bdi_destroy(&configfs_backing_dev_info);
296}