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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
44 static struct lock_class_key default_group_class[MAX_LOCK_DEPTH];
45 #endif
46
47 static 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
53 static const struct inode_operations configfs_inode_operations ={
54 .setattr = configfs_setattr,
55 };
56
57 int configfs_setattr(struct dentry * dentry, struct iattr * iattr)
58 {
59 struct inode * inode = d_inode(dentry);
60 struct configfs_dirent * sd = dentry->d_fsdata;
61 struct iattr * sd_iattr;
62 unsigned int ia_valid = iattr->ia_valid;
63 int error;
64
65 if (!sd)
66 return -EINVAL;
67
68 sd_iattr = sd->s_iattr;
69 if (!sd_iattr) {
70 /* setting attributes for the first time, allocate now */
71 sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL);
72 if (!sd_iattr)
73 return -ENOMEM;
74 /* assign default attributes */
75 sd_iattr->ia_mode = sd->s_mode;
76 sd_iattr->ia_uid = GLOBAL_ROOT_UID;
77 sd_iattr->ia_gid = GLOBAL_ROOT_GID;
78 sd_iattr->ia_atime = sd_iattr->ia_mtime =
79 sd_iattr->ia_ctime = current_fs_time(inode->i_sb);
80 sd->s_iattr = sd_iattr;
81 }
82 /* attributes were changed atleast once in past */
83
84 error = simple_setattr(dentry, iattr);
85 if (error)
86 return error;
87
88 if (ia_valid & ATTR_UID)
89 sd_iattr->ia_uid = iattr->ia_uid;
90 if (ia_valid & ATTR_GID)
91 sd_iattr->ia_gid = iattr->ia_gid;
92 if (ia_valid & ATTR_ATIME)
93 sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime,
94 inode->i_sb->s_time_gran);
95 if (ia_valid & ATTR_MTIME)
96 sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime,
97 inode->i_sb->s_time_gran);
98 if (ia_valid & ATTR_CTIME)
99 sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime,
100 inode->i_sb->s_time_gran);
101 if (ia_valid & ATTR_MODE) {
102 umode_t mode = iattr->ia_mode;
103
104 if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
105 mode &= ~S_ISGID;
106 sd_iattr->ia_mode = sd->s_mode = mode;
107 }
108
109 return error;
110 }
111
112 static inline void set_default_inode_attr(struct inode * inode, umode_t mode)
113 {
114 inode->i_mode = mode;
115 inode->i_atime = inode->i_mtime =
116 inode->i_ctime = current_fs_time(inode->i_sb);
117 }
118
119 static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
120 {
121 inode->i_mode = iattr->ia_mode;
122 inode->i_uid = iattr->ia_uid;
123 inode->i_gid = iattr->ia_gid;
124 inode->i_atime = iattr->ia_atime;
125 inode->i_mtime = iattr->ia_mtime;
126 inode->i_ctime = iattr->ia_ctime;
127 }
128
129 struct inode *configfs_new_inode(umode_t mode, struct configfs_dirent *sd,
130 struct super_block *s)
131 {
132 struct inode * inode = new_inode(s);
133 if (inode) {
134 inode->i_ino = get_next_ino();
135 inode->i_mapping->a_ops = &configfs_aops;
136 inode->i_op = &configfs_inode_operations;
137
138 if (sd->s_iattr) {
139 /* sysfs_dirent has non-default attributes
140 * get them for the new inode from persistent copy
141 * in sysfs_dirent
142 */
143 set_inode_attr(inode, sd->s_iattr);
144 } else
145 set_default_inode_attr(inode, mode);
146 }
147 return inode;
148 }
149
150 #ifdef CONFIG_LOCKDEP
151
152 static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
153 struct inode *inode)
154 {
155 int depth = sd->s_depth;
156
157 if (depth > 0) {
158 if (depth <= ARRAY_SIZE(default_group_class)) {
159 lockdep_set_class(&inode->i_rwsem,
160 &default_group_class[depth - 1]);
161 } else {
162 /*
163 * In practice the maximum level of locking depth is
164 * already reached. Just inform about possible reasons.
165 */
166 pr_info("Too many levels of inodes for the locking correctness validator.\n");
167 pr_info("Spurious warnings may appear.\n");
168 }
169 }
170 }
171
172 #else /* CONFIG_LOCKDEP */
173
174 static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
175 struct inode *inode)
176 {
177 }
178
179 #endif /* CONFIG_LOCKDEP */
180
181 int configfs_create(struct dentry * dentry, umode_t mode, void (*init)(struct inode *))
182 {
183 int error = 0;
184 struct inode *inode = NULL;
185 struct configfs_dirent *sd;
186 struct inode *p_inode;
187
188 if (!dentry)
189 return -ENOENT;
190
191 if (d_really_is_positive(dentry))
192 return -EEXIST;
193
194 sd = dentry->d_fsdata;
195 inode = configfs_new_inode(mode, sd, dentry->d_sb);
196 if (!inode)
197 return -ENOMEM;
198
199 p_inode = d_inode(dentry->d_parent);
200 p_inode->i_mtime = p_inode->i_ctime = current_fs_time(p_inode->i_sb);
201 configfs_set_inode_lock_class(sd, inode);
202
203 init(inode);
204 if (S_ISDIR(mode) || S_ISLNK(mode)) {
205 /*
206 * ->symlink(), ->mkdir(), configfs_register_subsystem() or
207 * create_default_group() - already hashed.
208 */
209 d_instantiate(dentry, inode);
210 dget(dentry); /* pin link and directory dentries in core */
211 } else {
212 /* ->lookup() */
213 d_add(dentry, inode);
214 }
215 return error;
216 }
217
218 /*
219 * Get the name for corresponding element represented by the given configfs_dirent
220 */
221 const unsigned char * configfs_get_name(struct configfs_dirent *sd)
222 {
223 struct configfs_attribute *attr;
224
225 BUG_ON(!sd || !sd->s_element);
226
227 /* These always have a dentry, so use that */
228 if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK))
229 return sd->s_dentry->d_name.name;
230
231 if (sd->s_type & (CONFIGFS_ITEM_ATTR | CONFIGFS_ITEM_BIN_ATTR)) {
232 attr = sd->s_element;
233 return attr->ca_name;
234 }
235 return NULL;
236 }
237
238
239 /*
240 * Unhashes the dentry corresponding to given configfs_dirent
241 * Called with parent inode's i_mutex held.
242 */
243 void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
244 {
245 struct dentry * dentry = sd->s_dentry;
246
247 if (dentry) {
248 spin_lock(&dentry->d_lock);
249 if (simple_positive(dentry)) {
250 dget_dlock(dentry);
251 __d_drop(dentry);
252 spin_unlock(&dentry->d_lock);
253 simple_unlink(d_inode(parent), dentry);
254 } else
255 spin_unlock(&dentry->d_lock);
256 }
257 }
258
259 void configfs_hash_and_remove(struct dentry * dir, const char * name)
260 {
261 struct configfs_dirent * sd;
262 struct configfs_dirent * parent_sd = dir->d_fsdata;
263
264 if (d_really_is_negative(dir))
265 /* no inode means this hasn't been made visible yet */
266 return;
267
268 inode_lock(d_inode(dir));
269 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
270 if (!sd->s_element)
271 continue;
272 if (!strcmp(configfs_get_name(sd), name)) {
273 spin_lock(&configfs_dirent_lock);
274 list_del_init(&sd->s_sibling);
275 spin_unlock(&configfs_dirent_lock);
276 configfs_drop_dentry(sd, dir);
277 configfs_put(sd);
278 break;
279 }
280 }
281 inode_unlock(d_inode(dir));
282 }