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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * inode.c - basic inode and dentry operations. | |
3 | * | |
4 | * sysfs is Copyright (c) 2001-3 Patrick Mochel | |
5 | * | |
6 | * Please see Documentation/filesystems/sysfs.txt for more information. | |
7 | */ | |
8 | ||
9 | #undef DEBUG | |
10 | ||
11 | #include <linux/pagemap.h> | |
12 | #include <linux/namei.h> | |
13 | #include <linux/backing-dev.h> | |
16f7e0fe | 14 | #include <linux/capability.h> |
1da177e4 LT |
15 | #include "sysfs.h" |
16 | ||
17 | extern struct super_block * sysfs_sb; | |
18 | ||
19 | static struct address_space_operations sysfs_aops = { | |
20 | .readpage = simple_readpage, | |
21 | .prepare_write = simple_prepare_write, | |
22 | .commit_write = simple_commit_write | |
23 | }; | |
24 | ||
25 | static struct backing_dev_info sysfs_backing_dev_info = { | |
26 | .ra_pages = 0, /* No readahead */ | |
27 | .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK, | |
28 | }; | |
29 | ||
988d186d MS |
30 | static struct inode_operations sysfs_inode_operations ={ |
31 | .setattr = sysfs_setattr, | |
32 | }; | |
33 | ||
34 | int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) | |
35 | { | |
36 | struct inode * inode = dentry->d_inode; | |
37 | struct sysfs_dirent * sd = dentry->d_fsdata; | |
38 | struct iattr * sd_iattr; | |
39 | unsigned int ia_valid = iattr->ia_valid; | |
40 | int error; | |
41 | ||
42 | if (!sd) | |
43 | return -EINVAL; | |
44 | ||
45 | sd_iattr = sd->s_iattr; | |
46 | ||
47 | error = inode_change_ok(inode, iattr); | |
48 | if (error) | |
49 | return error; | |
50 | ||
51 | error = inode_setattr(inode, iattr); | |
52 | if (error) | |
53 | return error; | |
54 | ||
55 | if (!sd_iattr) { | |
56 | /* setting attributes for the first time, allocate now */ | |
58d49283 | 57 | sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL); |
988d186d MS |
58 | if (!sd_iattr) |
59 | return -ENOMEM; | |
60 | /* assign default attributes */ | |
988d186d MS |
61 | sd_iattr->ia_mode = sd->s_mode; |
62 | sd_iattr->ia_uid = 0; | |
63 | sd_iattr->ia_gid = 0; | |
64 | sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime = CURRENT_TIME; | |
65 | sd->s_iattr = sd_iattr; | |
66 | } | |
67 | ||
68 | /* attributes were changed atleast once in past */ | |
69 | ||
70 | if (ia_valid & ATTR_UID) | |
71 | sd_iattr->ia_uid = iattr->ia_uid; | |
72 | if (ia_valid & ATTR_GID) | |
73 | sd_iattr->ia_gid = iattr->ia_gid; | |
74 | if (ia_valid & ATTR_ATIME) | |
75 | sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime, | |
76 | inode->i_sb->s_time_gran); | |
77 | if (ia_valid & ATTR_MTIME) | |
78 | sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime, | |
79 | inode->i_sb->s_time_gran); | |
80 | if (ia_valid & ATTR_CTIME) | |
81 | sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime, | |
82 | inode->i_sb->s_time_gran); | |
83 | if (ia_valid & ATTR_MODE) { | |
84 | umode_t mode = iattr->ia_mode; | |
85 | ||
86 | if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) | |
87 | mode &= ~S_ISGID; | |
9ca1eb32 | 88 | sd_iattr->ia_mode = sd->s_mode = mode; |
988d186d MS |
89 | } |
90 | ||
91 | return error; | |
92 | } | |
93 | ||
8215534c MS |
94 | static inline void set_default_inode_attr(struct inode * inode, mode_t mode) |
95 | { | |
96 | inode->i_mode = mode; | |
97 | inode->i_uid = 0; | |
98 | inode->i_gid = 0; | |
99 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
100 | } | |
101 | ||
102 | static inline void set_inode_attr(struct inode * inode, struct iattr * iattr) | |
103 | { | |
104 | inode->i_mode = iattr->ia_mode; | |
105 | inode->i_uid = iattr->ia_uid; | |
106 | inode->i_gid = iattr->ia_gid; | |
107 | inode->i_atime = iattr->ia_atime; | |
108 | inode->i_mtime = iattr->ia_mtime; | |
109 | inode->i_ctime = iattr->ia_ctime; | |
110 | } | |
111 | ||
112 | struct inode * sysfs_new_inode(mode_t mode, struct sysfs_dirent * sd) | |
1da177e4 LT |
113 | { |
114 | struct inode * inode = new_inode(sysfs_sb); | |
115 | if (inode) { | |
1da177e4 LT |
116 | inode->i_blksize = PAGE_CACHE_SIZE; |
117 | inode->i_blocks = 0; | |
1da177e4 LT |
118 | inode->i_mapping->a_ops = &sysfs_aops; |
119 | inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info; | |
8215534c MS |
120 | inode->i_op = &sysfs_inode_operations; |
121 | ||
122 | if (sd->s_iattr) { | |
123 | /* sysfs_dirent has non-default attributes | |
124 | * get them for the new inode from persistent copy | |
125 | * in sysfs_dirent | |
126 | */ | |
127 | set_inode_attr(inode, sd->s_iattr); | |
128 | } else | |
129 | set_default_inode_attr(inode, mode); | |
1da177e4 LT |
130 | } |
131 | return inode; | |
132 | } | |
133 | ||
134 | int sysfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *)) | |
135 | { | |
136 | int error = 0; | |
137 | struct inode * inode = NULL; | |
138 | if (dentry) { | |
139 | if (!dentry->d_inode) { | |
8215534c MS |
140 | struct sysfs_dirent * sd = dentry->d_fsdata; |
141 | if ((inode = sysfs_new_inode(mode, sd))) { | |
1da177e4 LT |
142 | if (dentry->d_parent && dentry->d_parent->d_inode) { |
143 | struct inode *p_inode = dentry->d_parent->d_inode; | |
144 | p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME; | |
145 | } | |
146 | goto Proceed; | |
147 | } | |
148 | else | |
149 | error = -ENOMEM; | |
150 | } else | |
151 | error = -EEXIST; | |
152 | } else | |
153 | error = -ENOENT; | |
154 | goto Done; | |
155 | ||
156 | Proceed: | |
157 | if (init) | |
158 | error = init(inode); | |
159 | if (!error) { | |
160 | d_instantiate(dentry, inode); | |
161 | if (S_ISDIR(mode)) | |
162 | dget(dentry); /* pin only directory dentry in core */ | |
163 | } else | |
164 | iput(inode); | |
165 | Done: | |
166 | return error; | |
167 | } | |
168 | ||
1da177e4 LT |
169 | /* |
170 | * Get the name for corresponding element represented by the given sysfs_dirent | |
171 | */ | |
172 | const unsigned char * sysfs_get_name(struct sysfs_dirent *sd) | |
173 | { | |
174 | struct attribute * attr; | |
175 | struct bin_attribute * bin_attr; | |
176 | struct sysfs_symlink * sl; | |
177 | ||
99cee0cd | 178 | BUG_ON(!sd || !sd->s_element); |
1da177e4 LT |
179 | |
180 | switch (sd->s_type) { | |
181 | case SYSFS_DIR: | |
182 | /* Always have a dentry so use that */ | |
183 | return sd->s_dentry->d_name.name; | |
184 | ||
185 | case SYSFS_KOBJ_ATTR: | |
186 | attr = sd->s_element; | |
187 | return attr->name; | |
188 | ||
189 | case SYSFS_KOBJ_BIN_ATTR: | |
190 | bin_attr = sd->s_element; | |
191 | return bin_attr->attr.name; | |
192 | ||
193 | case SYSFS_KOBJ_LINK: | |
194 | sl = sd->s_element; | |
195 | return sl->link_name; | |
196 | } | |
197 | return NULL; | |
198 | } | |
199 | ||
200 | ||
201 | /* | |
202 | * Unhashes the dentry corresponding to given sysfs_dirent | |
1b1dcc1b | 203 | * Called with parent inode's i_mutex held. |
1da177e4 LT |
204 | */ |
205 | void sysfs_drop_dentry(struct sysfs_dirent * sd, struct dentry * parent) | |
206 | { | |
207 | struct dentry * dentry = sd->s_dentry; | |
208 | ||
209 | if (dentry) { | |
210 | spin_lock(&dcache_lock); | |
211 | spin_lock(&dentry->d_lock); | |
212 | if (!(d_unhashed(dentry) && dentry->d_inode)) { | |
213 | dget_locked(dentry); | |
214 | __d_drop(dentry); | |
215 | spin_unlock(&dentry->d_lock); | |
216 | spin_unlock(&dcache_lock); | |
217 | simple_unlink(parent->d_inode, dentry); | |
218 | } else { | |
219 | spin_unlock(&dentry->d_lock); | |
220 | spin_unlock(&dcache_lock); | |
221 | } | |
222 | } | |
223 | } | |
224 | ||
225 | void sysfs_hash_and_remove(struct dentry * dir, const char * name) | |
226 | { | |
227 | struct sysfs_dirent * sd; | |
641e6f30 GKH |
228 | struct sysfs_dirent * parent_sd; |
229 | ||
230 | if (!dir) | |
231 | return; | |
1da177e4 | 232 | |
36676bcb JB |
233 | if (dir->d_inode == NULL) |
234 | /* no inode means this hasn't been made visible yet */ | |
235 | return; | |
236 | ||
641e6f30 | 237 | parent_sd = dir->d_fsdata; |
1b1dcc1b | 238 | mutex_lock(&dir->d_inode->i_mutex); |
1da177e4 LT |
239 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { |
240 | if (!sd->s_element) | |
241 | continue; | |
242 | if (!strcmp(sysfs_get_name(sd), name)) { | |
243 | list_del_init(&sd->s_sibling); | |
244 | sysfs_drop_dentry(sd, dir); | |
245 | sysfs_put(sd); | |
246 | break; | |
247 | } | |
248 | } | |
1b1dcc1b | 249 | mutex_unlock(&dir->d_inode->i_mutex); |
1da177e4 | 250 | } |