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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> |
7063fbf2 JB |
36 | |
37 | #include <linux/configfs.h> | |
38 | #include "configfs_internal.h" | |
39 | ||
40 | extern struct super_block * configfs_sb; | |
41 | ||
f5e54d6e | 42 | static const struct address_space_operations configfs_aops = { |
7063fbf2 | 43 | .readpage = simple_readpage, |
800d15a5 NP |
44 | .write_begin = simple_write_begin, |
45 | .write_end = simple_write_end, | |
7063fbf2 JB |
46 | }; |
47 | ||
48 | static struct backing_dev_info configfs_backing_dev_info = { | |
49 | .ra_pages = 0, /* No readahead */ | |
e4ad08fe | 50 | .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, |
7063fbf2 JB |
51 | }; |
52 | ||
754661f1 | 53 | static const struct inode_operations configfs_inode_operations ={ |
3d0f89bb JB |
54 | .setattr = configfs_setattr, |
55 | }; | |
56 | ||
57 | int configfs_setattr(struct dentry * dentry, struct iattr * iattr) | |
58 | { | |
59 | struct inode * inode = dentry->d_inode; | |
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 | ||
70 | error = inode_change_ok(inode, iattr); | |
71 | if (error) | |
72 | return error; | |
73 | ||
74 | error = inode_setattr(inode, iattr); | |
75 | if (error) | |
76 | return error; | |
77 | ||
78 | if (!sd_iattr) { | |
79 | /* setting attributes for the first time, allocate now */ | |
f8314dc6 | 80 | sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL); |
3d0f89bb JB |
81 | if (!sd_iattr) |
82 | return -ENOMEM; | |
83 | /* assign default attributes */ | |
3d0f89bb JB |
84 | sd_iattr->ia_mode = sd->s_mode; |
85 | sd_iattr->ia_uid = 0; | |
86 | sd_iattr->ia_gid = 0; | |
87 | sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime = CURRENT_TIME; | |
88 | sd->s_iattr = sd_iattr; | |
89 | } | |
90 | ||
91 | /* attributes were changed atleast once in past */ | |
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 | ||
117 | static inline void set_default_inode_attr(struct inode * inode, mode_t mode) | |
118 | { | |
119 | inode->i_mode = mode; | |
3d0f89bb JB |
120 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
121 | } | |
122 | ||
123 | static 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 | ||
133 | struct inode * configfs_new_inode(mode_t mode, struct configfs_dirent * sd) | |
7063fbf2 JB |
134 | { |
135 | struct inode * inode = new_inode(configfs_sb); | |
136 | if (inode) { | |
7063fbf2 JB |
137 | inode->i_mapping->a_ops = &configfs_aops; |
138 | inode->i_mapping->backing_dev_info = &configfs_backing_dev_info; | |
3d0f89bb JB |
139 | inode->i_op = &configfs_inode_operations; |
140 | ||
141 | if (sd->s_iattr) { | |
142 | /* sysfs_dirent has non-default attributes | |
143 | * get them for the new inode from persistent copy | |
144 | * in sysfs_dirent | |
145 | */ | |
146 | set_inode_attr(inode, sd->s_iattr); | |
147 | } else | |
148 | set_default_inode_attr(inode, mode); | |
7063fbf2 JB |
149 | } |
150 | return inode; | |
151 | } | |
152 | ||
153 | int configfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *)) | |
154 | { | |
155 | int error = 0; | |
156 | struct inode * inode = NULL; | |
157 | if (dentry) { | |
158 | if (!dentry->d_inode) { | |
3d0f89bb JB |
159 | struct configfs_dirent *sd = dentry->d_fsdata; |
160 | if ((inode = configfs_new_inode(mode, sd))) { | |
7063fbf2 JB |
161 | if (dentry->d_parent && dentry->d_parent->d_inode) { |
162 | struct inode *p_inode = dentry->d_parent->d_inode; | |
163 | p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME; | |
164 | } | |
165 | goto Proceed; | |
166 | } | |
167 | else | |
168 | error = -ENOMEM; | |
169 | } else | |
170 | error = -EEXIST; | |
171 | } else | |
172 | error = -ENOENT; | |
173 | goto Done; | |
174 | ||
175 | Proceed: | |
176 | if (init) | |
177 | error = init(inode); | |
178 | if (!error) { | |
179 | d_instantiate(dentry, inode); | |
180 | if (S_ISDIR(mode) || S_ISLNK(mode)) | |
181 | dget(dentry); /* pin link and directory dentries in core */ | |
182 | } else | |
183 | iput(inode); | |
184 | Done: | |
185 | return error; | |
186 | } | |
187 | ||
188 | /* | |
189 | * Get the name for corresponding element represented by the given configfs_dirent | |
190 | */ | |
191 | const unsigned char * configfs_get_name(struct configfs_dirent *sd) | |
192 | { | |
3d0f89bb | 193 | struct configfs_attribute *attr; |
7063fbf2 | 194 | |
1a1974fd | 195 | BUG_ON(!sd || !sd->s_element); |
7063fbf2 JB |
196 | |
197 | /* These always have a dentry, so use that */ | |
198 | if (sd->s_type & (CONFIGFS_DIR | CONFIGFS_ITEM_LINK)) | |
199 | return sd->s_dentry->d_name.name; | |
200 | ||
201 | if (sd->s_type & CONFIGFS_ITEM_ATTR) { | |
202 | attr = sd->s_element; | |
3d0f89bb | 203 | return attr->ca_name; |
7063fbf2 JB |
204 | } |
205 | return NULL; | |
206 | } | |
207 | ||
208 | ||
209 | /* | |
210 | * Unhashes the dentry corresponding to given configfs_dirent | |
1b1dcc1b | 211 | * Called with parent inode's i_mutex held. |
7063fbf2 JB |
212 | */ |
213 | void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent) | |
214 | { | |
215 | struct dentry * dentry = sd->s_dentry; | |
216 | ||
217 | if (dentry) { | |
218 | spin_lock(&dcache_lock); | |
3d0f89bb | 219 | spin_lock(&dentry->d_lock); |
7063fbf2 JB |
220 | if (!(d_unhashed(dentry) && dentry->d_inode)) { |
221 | dget_locked(dentry); | |
222 | __d_drop(dentry); | |
3d0f89bb | 223 | spin_unlock(&dentry->d_lock); |
7063fbf2 JB |
224 | spin_unlock(&dcache_lock); |
225 | simple_unlink(parent->d_inode, dentry); | |
3d0f89bb JB |
226 | } else { |
227 | spin_unlock(&dentry->d_lock); | |
7063fbf2 | 228 | spin_unlock(&dcache_lock); |
3d0f89bb | 229 | } |
7063fbf2 JB |
230 | } |
231 | } | |
232 | ||
233 | void configfs_hash_and_remove(struct dentry * dir, const char * name) | |
234 | { | |
235 | struct configfs_dirent * sd; | |
236 | struct configfs_dirent * parent_sd = dir->d_fsdata; | |
237 | ||
3d0f89bb JB |
238 | if (dir->d_inode == NULL) |
239 | /* no inode means this hasn't been made visible yet */ | |
240 | return; | |
241 | ||
1b1dcc1b | 242 | mutex_lock(&dir->d_inode->i_mutex); |
7063fbf2 JB |
243 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { |
244 | if (!sd->s_element) | |
245 | continue; | |
246 | if (!strcmp(configfs_get_name(sd), name)) { | |
6f610764 | 247 | spin_lock(&configfs_dirent_lock); |
7063fbf2 | 248 | list_del_init(&sd->s_sibling); |
6f610764 | 249 | spin_unlock(&configfs_dirent_lock); |
7063fbf2 JB |
250 | configfs_drop_dentry(sd, dir); |
251 | configfs_put(sd); | |
252 | break; | |
253 | } | |
254 | } | |
1b1dcc1b | 255 | mutex_unlock(&dir->d_inode->i_mutex); |
7063fbf2 JB |
256 | } |
257 | ||
e0bf68dd PZ |
258 | int __init configfs_inode_init(void) |
259 | { | |
260 | return bdi_init(&configfs_backing_dev_info); | |
261 | } | |
7063fbf2 | 262 | |
e0bf68dd PZ |
263 | void __exit configfs_inode_exit(void) |
264 | { | |
265 | bdi_destroy(&configfs_backing_dev_info); | |
266 | } |