Line data Source code
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.txt for more information.
27 : */
28 :
29 : #undef DEBUG
30 :
31 : #include <linux/pagemap.h>
32 : #include <linux/namei.h>
33 : #include <linux/backing-dev.h>
34 : #include <linux/capability.h>
35 : #include <linux/sched.h>
36 : #include <linux/lockdep.h>
37 :
38 : #include <linux/configfs.h>
39 : #include "configfs_internal.h"
40 :
41 : #ifdef CONFIG_LOCKDEP
42 : static struct lock_class_key default_group_class[MAX_LOCK_DEPTH];
43 : #endif
44 :
45 : extern struct super_block * configfs_sb;
46 :
47 1 : 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 1 : static 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 :
59 1 : static const struct inode_operations configfs_inode_operations ={
60 : .setattr = configfs_setattr,
61 : };
62 :
63 : int configfs_setattr(struct dentry * dentry, struct iattr * iattr)
64 : {
65 2 : struct inode * inode = dentry->d_inode;
66 3 : struct configfs_dirent * sd = dentry->d_fsdata;
67 1 : struct iattr * sd_iattr;
68 2 : unsigned int ia_valid = iattr->ia_valid;
69 1 : int error;
70 1 :
71 3 : if (!sd)
72 2 : return -EINVAL;
73 1 :
74 2 : sd_iattr = sd->s_iattr;
75 1 :
76 2 : error = inode_change_ok(inode, iattr);
77 2 : if (error)
78 1 : return error;
79 :
80 1 : error = inode_setattr(inode, iattr);
81 2 : if (error)
82 1 : return error;
83 :
84 2 : if (!sd_iattr) {
85 : /* setting attributes for the first time, allocate now */
86 3 : sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL);
87 2 : if (!sd_iattr)
88 1 : return -ENOMEM;
89 : /* assign default attributes */
90 1 : sd_iattr->ia_mode = sd->s_mode;
91 1 : sd_iattr->ia_uid = 0;
92 1 : sd_iattr->ia_gid = 0;
93 5 : sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime = CURRENT_TIME;
94 1 : sd->s_iattr = sd_iattr;
95 : }
96 :
97 : /* attributes were changed atleast once in past */
98 :
99 4 : if (ia_valid & ATTR_UID)
100 2 : sd_iattr->ia_uid = iattr->ia_uid;
101 4 : if (ia_valid & ATTR_GID)
102 2 : sd_iattr->ia_gid = iattr->ia_gid;
103 4 : if (ia_valid & ATTR_ATIME)
104 2 : sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime,
105 : inode->i_sb->s_time_gran);
106 4 : if (ia_valid & ATTR_MTIME)
107 2 : sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime,
108 : inode->i_sb->s_time_gran);
109 4 : if (ia_valid & ATTR_CTIME)
110 2 : sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime,
111 : inode->i_sb->s_time_gran);
112 4 : if (ia_valid & ATTR_MODE) {
113 2 : umode_t mode = iattr->ia_mode;
114 :
115 12 : if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
116 2 : mode &= ~S_ISGID;
117 6 : sd_iattr->ia_mode = sd->s_mode = mode;
118 : }
119 :
120 2 : return error;
121 : }
122 :
123 : static inline void set_default_inode_attr(struct inode * inode, mode_t mode)
124 : {
125 8 : inode->i_mode = mode;
126 24 : inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
127 4 : }
128 :
129 : static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
130 : {
131 4 : inode->i_mode = iattr->ia_mode;
132 4 : inode->i_uid = iattr->ia_uid;
133 4 : inode->i_gid = iattr->ia_gid;
134 4 : inode->i_atime = iattr->ia_atime;
135 4 : inode->i_mtime = iattr->ia_mtime;
136 4 : inode->i_ctime = iattr->ia_ctime;
137 4 : }
138 :
139 : struct inode * configfs_new_inode(mode_t mode, struct configfs_dirent * sd)
140 : {
141 12 : struct inode * inode = new_inode(configfs_sb);
142 12 : if (inode) {
143 4 : inode->i_mapping->a_ops = &configfs_aops;
144 4 : inode->i_mapping->backing_dev_info = &configfs_backing_dev_info;
145 4 : inode->i_op = &configfs_inode_operations;
146 :
147 12 : if (sd->s_iattr) {
148 : /* sysfs_dirent has non-default attributes
149 : * get them for the new inode from persistent copy
150 : * in sysfs_dirent
151 : */
152 8 : set_inode_attr(inode, sd->s_iattr);
153 : } else
154 8 : set_default_inode_attr(inode, mode);
155 : }
156 12 : return inode;
157 : }
158 :
159 : #ifdef CONFIG_LOCKDEP
160 :
161 : static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
162 : struct inode *inode)
163 : {
164 : int depth = sd->s_depth;
165 :
166 : if (depth > 0) {
167 : if (depth <= ARRAY_SIZE(default_group_class)) {
168 : lockdep_set_class(&inode->i_mutex,
169 : &default_group_class[depth - 1]);
170 : } else {
171 : /*
172 : * In practice the maximum level of locking depth is
173 : * already reached. Just inform about possible reasons.
174 : */
175 : printk(KERN_INFO "configfs: Too many levels of inodes"
176 : " for the locking correctness validator.\n");
177 : printk(KERN_INFO "Spurious warnings may appear.\n");
178 : }
179 : }
180 : }
181 :
182 : #else /* CONFIG_LOCKDEP */
183 :
184 : static void configfs_set_inode_lock_class(struct configfs_dirent *sd,
185 : struct inode *inode)
186 4 : {
187 : }
188 :
189 : #endif /* CONFIG_LOCKDEP */
190 :
191 : int configfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *))
192 : {
193 8 : int error = 0;
194 8 : struct inode * inode = NULL;
195 12 : if (dentry) {
196 16 : if (!dentry->d_inode) {
197 12 : struct configfs_dirent *sd = dentry->d_fsdata;
198 24 : if ((inode = configfs_new_inode(mode, sd))) {
199 24 : if (dentry->d_parent && dentry->d_parent->d_inode) {
200 4 : struct inode *p_inode = dentry->d_parent->d_inode;
201 12 : p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME;
202 : }
203 8 : configfs_set_inode_lock_class(sd, inode);
204 4 : goto Proceed;
205 : }
206 : else
207 4 : error = -ENOMEM;
208 : } else
209 4 : error = -EEXIST;
210 : } else
211 4 : error = -ENOENT;
212 8 : goto Done;
213 4 :
214 : Proceed:
215 8 : if (init)
216 19 : error = init(inode);
217 16 : if (!error) {
218 8 : d_instantiate(dentry, inode);
219 32 : if (S_ISDIR(mode) || S_ISLNK(mode))
220 24 : dget(dentry); /* pin link and directory dentries in core */
221 : } else
222 8 : iput(inode);
223 : Done:
224 20 : return error;
225 12 : }
226 :
227 : /*
228 : * Get the name for corresponding element represented by the given configfs_dirent
229 : */
230 : const unsigned char * configfs_get_name(struct configfs_dirent *sd)
231 : {
232 4 : struct configfs_attribute *attr;
233 4 :
234 56 : BUG_ON(!sd || !sd->s_element);
235 :
236 : /* These always have a dentry, so use that */
237 16 : if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK))
238 8 : return sd->s_dentry->d_name.name;
239 :
240 16 : if (sd->s_type & CONFIGFS_ITEM_ATTR) {
241 16 : attr = sd->s_element;
242 16 : return attr->ca_name;
243 : }
244 8 : return NULL;
245 : }
246 :
247 :
248 : /*
249 : * Unhashes the dentry corresponding to given configfs_dirent
250 : * Called with parent inode's i_mutex held.
251 : */
252 : void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
253 : {
254 22 : struct dentry * dentry = sd->s_dentry;
255 11 :
256 22 : if (dentry) {
257 22 : spin_lock(&dcache_lock);
258 22 : spin_lock(&dentry->d_lock);
259 77 : if (!(d_unhashed(dentry) && dentry->d_inode)) {
260 11 : dget_locked(dentry);
261 33 : __d_drop(dentry);
262 22 : spin_unlock(&dentry->d_lock);
263 22 : spin_unlock(&dcache_lock);
264 11 : simple_unlink(parent->d_inode, dentry);
265 : } else {
266 22 : spin_unlock(&dentry->d_lock);
267 22 : spin_unlock(&dcache_lock);
268 : }
269 : }
270 33 : }
271 :
272 : void configfs_hash_and_remove(struct dentry * dir, const char * name)
273 : {
274 0 : struct configfs_dirent * sd;
275 0 : struct configfs_dirent * parent_sd = dir->d_fsdata;
276 0 :
277 0 : if (dir->d_inode == NULL)
278 0 : /* no inode means this hasn't been made visible yet */
279 0 : return;
280 :
281 0 : mutex_lock(&dir->d_inode->i_mutex);
282 0 : list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
283 0 : if (!sd->s_element)
284 0 : continue;
285 0 : if (!strcmp(configfs_get_name(sd), name)) {
286 0 : spin_lock(&configfs_dirent_lock);
287 0 : list_del_init(&sd->s_sibling);
288 0 : spin_unlock(&configfs_dirent_lock);
289 0 : configfs_drop_dentry(sd, dir);
290 0 : configfs_put(sd);
291 0 : break;
292 : }
293 : }
294 0 : mutex_unlock(&dir->d_inode->i_mutex);
295 0 : }
296 :
297 : int __init configfs_inode_init(void)
298 : {
299 3 : return bdi_init(&configfs_backing_dev_info);
300 : }
301 :
302 : void __exit configfs_inode_exit(void)
303 : {
304 2 : bdi_destroy(&configfs_backing_dev_info);
305 2 : }
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