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