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7063fbf2 JB |
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 | * | |
395cf969 PB |
26 | * Please see Documentation/filesystems/configfs/configfs.txt for more |
27 | * information. | |
7063fbf2 JB |
28 | */ |
29 | ||
30 | #undef DEBUG | |
31 | ||
32 | #include <linux/pagemap.h> | |
33 | #include <linux/namei.h> | |
34 | #include <linux/backing-dev.h> | |
3d0f89bb | 35 | #include <linux/capability.h> |
e8edc6e0 | 36 | #include <linux/sched.h> |
e74cc06d | 37 | #include <linux/lockdep.h> |
5a0e3ad6 | 38 | #include <linux/slab.h> |
7063fbf2 JB |
39 | |
40 | #include <linux/configfs.h> | |
41 | #include "configfs_internal.h" | |
42 | ||
e74cc06d LR |
43 | #ifdef CONFIG_LOCKDEP |
44 | static struct lock_class_key default_group_class[MAX_LOCK_DEPTH]; | |
45 | #endif | |
46 | ||
7063fbf2 JB |
47 | extern struct super_block * configfs_sb; |
48 | ||
f5e54d6e | 49 | static const struct address_space_operations configfs_aops = { |
7063fbf2 | 50 | .readpage = simple_readpage, |
800d15a5 NP |
51 | .write_begin = simple_write_begin, |
52 | .write_end = simple_write_end, | |
7063fbf2 JB |
53 | }; |
54 | ||
55 | static struct backing_dev_info configfs_backing_dev_info = { | |
d993831f | 56 | .name = "configfs", |
7063fbf2 | 57 | .ra_pages = 0, /* No readahead */ |
e4ad08fe | 58 | .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, |
7063fbf2 JB |
59 | }; |
60 | ||
754661f1 | 61 | static const struct inode_operations configfs_inode_operations ={ |
3d0f89bb JB |
62 | .setattr = configfs_setattr, |
63 | }; | |
64 | ||
65 | int configfs_setattr(struct dentry * dentry, struct iattr * iattr) | |
66 | { | |
67 | struct inode * inode = dentry->d_inode; | |
68 | struct configfs_dirent * sd = dentry->d_fsdata; | |
69 | struct iattr * sd_iattr; | |
70 | unsigned int ia_valid = iattr->ia_valid; | |
71 | int error; | |
72 | ||
73 | if (!sd) | |
74 | return -EINVAL; | |
75 | ||
3322e79a | 76 | sd_iattr = sd->s_iattr; |
3d0f89bb JB |
77 | if (!sd_iattr) { |
78 | /* setting attributes for the first time, allocate now */ | |
f8314dc6 | 79 | sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL); |
3d0f89bb JB |
80 | if (!sd_iattr) |
81 | return -ENOMEM; | |
82 | /* assign default attributes */ | |
3d0f89bb JB |
83 | sd_iattr->ia_mode = sd->s_mode; |
84 | sd_iattr->ia_uid = 0; | |
85 | sd_iattr->ia_gid = 0; | |
86 | sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime = CURRENT_TIME; | |
87 | sd->s_iattr = sd_iattr; | |
88 | } | |
3d0f89bb JB |
89 | /* attributes were changed atleast once in past */ |
90 | ||
75de46b9 NP |
91 | error = simple_setattr(dentry, iattr); |
92 | if (error) | |
93 | return error; | |
94 | ||
3d0f89bb JB |
95 | if (ia_valid & ATTR_UID) |
96 | sd_iattr->ia_uid = iattr->ia_uid; | |
97 | if (ia_valid & ATTR_GID) | |
98 | sd_iattr->ia_gid = iattr->ia_gid; | |
99 | if (ia_valid & ATTR_ATIME) | |
100 | sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime, | |
101 | inode->i_sb->s_time_gran); | |
102 | if (ia_valid & ATTR_MTIME) | |
103 | sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime, | |
104 | inode->i_sb->s_time_gran); | |
105 | if (ia_valid & ATTR_CTIME) | |
106 | sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime, | |
107 | inode->i_sb->s_time_gran); | |
108 | if (ia_valid & ATTR_MODE) { | |
109 | umode_t mode = iattr->ia_mode; | |
110 | ||
111 | if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) | |
112 | mode &= ~S_ISGID; | |
113 | sd_iattr->ia_mode = sd->s_mode = mode; | |
114 | } | |
115 | ||
116 | return error; | |
117 | } | |
118 | ||
119 | static inline void set_default_inode_attr(struct inode * inode, mode_t mode) | |
120 | { | |
121 | inode->i_mode = mode; | |
3d0f89bb JB |
122 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
123 | } | |
124 | ||
125 | static inline void set_inode_attr(struct inode * inode, struct iattr * iattr) | |
126 | { | |
127 | inode->i_mode = iattr->ia_mode; | |
128 | inode->i_uid = iattr->ia_uid; | |
129 | inode->i_gid = iattr->ia_gid; | |
130 | inode->i_atime = iattr->ia_atime; | |
131 | inode->i_mtime = iattr->ia_mtime; | |
132 | inode->i_ctime = iattr->ia_ctime; | |
133 | } | |
134 | ||
135 | struct inode * configfs_new_inode(mode_t mode, struct configfs_dirent * sd) | |
7063fbf2 JB |
136 | { |
137 | struct inode * inode = new_inode(configfs_sb); | |
138 | if (inode) { | |
85fe4025 | 139 | inode->i_ino = get_next_ino(); |
7063fbf2 JB |
140 | inode->i_mapping->a_ops = &configfs_aops; |
141 | inode->i_mapping->backing_dev_info = &configfs_backing_dev_info; | |
3d0f89bb JB |
142 | inode->i_op = &configfs_inode_operations; |
143 | ||
144 | if (sd->s_iattr) { | |
145 | /* sysfs_dirent has non-default attributes | |
146 | * get them for the new inode from persistent copy | |
147 | * in sysfs_dirent | |
148 | */ | |
149 | set_inode_attr(inode, sd->s_iattr); | |
150 | } else | |
151 | set_default_inode_attr(inode, mode); | |
7063fbf2 JB |
152 | } |
153 | return inode; | |
154 | } | |
155 | ||
e74cc06d LR |
156 | #ifdef CONFIG_LOCKDEP |
157 | ||
158 | static void configfs_set_inode_lock_class(struct configfs_dirent *sd, | |
159 | struct inode *inode) | |
160 | { | |
161 | int depth = sd->s_depth; | |
162 | ||
163 | if (depth > 0) { | |
164 | if (depth <= ARRAY_SIZE(default_group_class)) { | |
165 | lockdep_set_class(&inode->i_mutex, | |
166 | &default_group_class[depth - 1]); | |
167 | } else { | |
168 | /* | |
169 | * In practice the maximum level of locking depth is | |
170 | * already reached. Just inform about possible reasons. | |
171 | */ | |
172 | printk(KERN_INFO "configfs: Too many levels of inodes" | |
173 | " for the locking correctness validator.\n"); | |
174 | printk(KERN_INFO "Spurious warnings may appear.\n"); | |
175 | } | |
176 | } | |
177 | } | |
178 | ||
179 | #else /* CONFIG_LOCKDEP */ | |
180 | ||
181 | static void configfs_set_inode_lock_class(struct configfs_dirent *sd, | |
182 | struct inode *inode) | |
183 | { | |
184 | } | |
185 | ||
186 | #endif /* CONFIG_LOCKDEP */ | |
187 | ||
7063fbf2 JB |
188 | int configfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *)) |
189 | { | |
190 | int error = 0; | |
191 | struct inode * inode = NULL; | |
192 | if (dentry) { | |
193 | if (!dentry->d_inode) { | |
3d0f89bb JB |
194 | struct configfs_dirent *sd = dentry->d_fsdata; |
195 | if ((inode = configfs_new_inode(mode, sd))) { | |
7063fbf2 JB |
196 | if (dentry->d_parent && dentry->d_parent->d_inode) { |
197 | struct inode *p_inode = dentry->d_parent->d_inode; | |
198 | p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME; | |
199 | } | |
e74cc06d | 200 | configfs_set_inode_lock_class(sd, inode); |
7063fbf2 JB |
201 | goto Proceed; |
202 | } | |
203 | else | |
204 | error = -ENOMEM; | |
205 | } else | |
206 | error = -EEXIST; | |
207 | } else | |
208 | error = -ENOENT; | |
209 | goto Done; | |
210 | ||
211 | Proceed: | |
212 | if (init) | |
213 | error = init(inode); | |
214 | if (!error) { | |
215 | d_instantiate(dentry, inode); | |
216 | if (S_ISDIR(mode) || S_ISLNK(mode)) | |
217 | dget(dentry); /* pin link and directory dentries in core */ | |
218 | } else | |
219 | iput(inode); | |
220 | Done: | |
221 | return error; | |
222 | } | |
223 | ||
224 | /* | |
225 | * Get the name for corresponding element represented by the given configfs_dirent | |
226 | */ | |
227 | const unsigned char * configfs_get_name(struct configfs_dirent *sd) | |
228 | { | |
3d0f89bb | 229 | struct configfs_attribute *attr; |
7063fbf2 | 230 | |
1a1974fd | 231 | BUG_ON(!sd || !sd->s_element); |
7063fbf2 JB |
232 | |
233 | /* These always have a dentry, so use that */ | |
234 | if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK)) | |
235 | return sd->s_dentry->d_name.name; | |
236 | ||
237 | if (sd->s_type & CONFIGFS_ITEM_ATTR) { | |
238 | attr = sd->s_element; | |
3d0f89bb | 239 | return attr->ca_name; |
7063fbf2 JB |
240 | } |
241 | return NULL; | |
242 | } | |
243 | ||
244 | ||
245 | /* | |
246 | * Unhashes the dentry corresponding to given configfs_dirent | |
1b1dcc1b | 247 | * Called with parent inode's i_mutex held. |
7063fbf2 JB |
248 | */ |
249 | void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent) | |
250 | { | |
251 | struct dentry * dentry = sd->s_dentry; | |
252 | ||
253 | if (dentry) { | |
3d0f89bb | 254 | spin_lock(&dentry->d_lock); |
7063fbf2 | 255 | if (!(d_unhashed(dentry) && dentry->d_inode)) { |
dc0474be | 256 | dget_dlock(dentry); |
7063fbf2 | 257 | __d_drop(dentry); |
3d0f89bb | 258 | spin_unlock(&dentry->d_lock); |
7063fbf2 | 259 | simple_unlink(parent->d_inode, dentry); |
b5c84bf6 | 260 | } else |
3d0f89bb | 261 | spin_unlock(&dentry->d_lock); |
7063fbf2 JB |
262 | } |
263 | } | |
264 | ||
265 | void configfs_hash_and_remove(struct dentry * dir, const char * name) | |
266 | { | |
267 | struct configfs_dirent * sd; | |
268 | struct configfs_dirent * parent_sd = dir->d_fsdata; | |
269 | ||
3d0f89bb JB |
270 | if (dir->d_inode == NULL) |
271 | /* no inode means this hasn't been made visible yet */ | |
272 | return; | |
273 | ||
1b1dcc1b | 274 | mutex_lock(&dir->d_inode->i_mutex); |
7063fbf2 JB |
275 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { |
276 | if (!sd->s_element) | |
277 | continue; | |
278 | if (!strcmp(configfs_get_name(sd), name)) { | |
6f610764 | 279 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 280 | list_del_init(&sd->s_sibling); |
6f610764 | 281 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
282 | configfs_drop_dentry(sd, dir); |
283 | configfs_put(sd); | |
284 | break; | |
285 | } | |
286 | } | |
1b1dcc1b | 287 | mutex_unlock(&dir->d_inode->i_mutex); |
7063fbf2 JB |
288 | } |
289 | ||
e0bf68dd PZ |
290 | int __init configfs_inode_init(void) |
291 | { | |
292 | return bdi_init(&configfs_backing_dev_info); | |
293 | } | |
7063fbf2 | 294 | |
7c6455e3 | 295 | void configfs_inode_exit(void) |
e0bf68dd PZ |
296 | { |
297 | bdi_destroy(&configfs_backing_dev_info); | |
298 | } |