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 */ | |
57 | sd_iattr = kmalloc(sizeof(struct iattr), GFP_KERNEL); | |
58 | if (!sd_iattr) | |
59 | return -ENOMEM; | |
60 | /* assign default attributes */ | |
61 | memset(sd_iattr, 0, sizeof(struct iattr)); | |
62 | sd_iattr->ia_mode = sd->s_mode; | |
63 | sd_iattr->ia_uid = 0; | |
64 | sd_iattr->ia_gid = 0; | |
65 | sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime = CURRENT_TIME; | |
66 | sd->s_iattr = sd_iattr; | |
67 | } | |
68 | ||
69 | /* attributes were changed atleast once in past */ | |
70 | ||
71 | if (ia_valid & ATTR_UID) | |
72 | sd_iattr->ia_uid = iattr->ia_uid; | |
73 | if (ia_valid & ATTR_GID) | |
74 | sd_iattr->ia_gid = iattr->ia_gid; | |
75 | if (ia_valid & ATTR_ATIME) | |
76 | sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime, | |
77 | inode->i_sb->s_time_gran); | |
78 | if (ia_valid & ATTR_MTIME) | |
79 | sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime, | |
80 | inode->i_sb->s_time_gran); | |
81 | if (ia_valid & ATTR_CTIME) | |
82 | sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime, | |
83 | inode->i_sb->s_time_gran); | |
84 | if (ia_valid & ATTR_MODE) { | |
85 | umode_t mode = iattr->ia_mode; | |
86 | ||
87 | if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) | |
88 | mode &= ~S_ISGID; | |
9ca1eb32 | 89 | sd_iattr->ia_mode = sd->s_mode = mode; |
988d186d MS |
90 | } |
91 | ||
92 | return error; | |
93 | } | |
94 | ||
8215534c MS |
95 | static inline void set_default_inode_attr(struct inode * inode, mode_t mode) |
96 | { | |
97 | inode->i_mode = mode; | |
98 | inode->i_uid = 0; | |
99 | inode->i_gid = 0; | |
100 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
101 | } | |
102 | ||
103 | static inline void set_inode_attr(struct inode * inode, struct iattr * iattr) | |
104 | { | |
105 | inode->i_mode = iattr->ia_mode; | |
106 | inode->i_uid = iattr->ia_uid; | |
107 | inode->i_gid = iattr->ia_gid; | |
108 | inode->i_atime = iattr->ia_atime; | |
109 | inode->i_mtime = iattr->ia_mtime; | |
110 | inode->i_ctime = iattr->ia_ctime; | |
111 | } | |
112 | ||
113 | struct inode * sysfs_new_inode(mode_t mode, struct sysfs_dirent * sd) | |
1da177e4 LT |
114 | { |
115 | struct inode * inode = new_inode(sysfs_sb); | |
116 | if (inode) { | |
1da177e4 LT |
117 | inode->i_blksize = PAGE_CACHE_SIZE; |
118 | inode->i_blocks = 0; | |
1da177e4 LT |
119 | inode->i_mapping->a_ops = &sysfs_aops; |
120 | inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info; | |
8215534c MS |
121 | inode->i_op = &sysfs_inode_operations; |
122 | ||
123 | if (sd->s_iattr) { | |
124 | /* sysfs_dirent has non-default attributes | |
125 | * get them for the new inode from persistent copy | |
126 | * in sysfs_dirent | |
127 | */ | |
128 | set_inode_attr(inode, sd->s_iattr); | |
129 | } else | |
130 | set_default_inode_attr(inode, mode); | |
1da177e4 LT |
131 | } |
132 | return inode; | |
133 | } | |
134 | ||
135 | int sysfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *)) | |
136 | { | |
137 | int error = 0; | |
138 | struct inode * inode = NULL; | |
139 | if (dentry) { | |
140 | if (!dentry->d_inode) { | |
8215534c MS |
141 | struct sysfs_dirent * sd = dentry->d_fsdata; |
142 | if ((inode = sysfs_new_inode(mode, sd))) { | |
1da177e4 LT |
143 | if (dentry->d_parent && dentry->d_parent->d_inode) { |
144 | struct inode *p_inode = dentry->d_parent->d_inode; | |
145 | p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME; | |
146 | } | |
147 | goto Proceed; | |
148 | } | |
149 | else | |
150 | error = -ENOMEM; | |
151 | } else | |
152 | error = -EEXIST; | |
153 | } else | |
154 | error = -ENOENT; | |
155 | goto Done; | |
156 | ||
157 | Proceed: | |
158 | if (init) | |
159 | error = init(inode); | |
160 | if (!error) { | |
161 | d_instantiate(dentry, inode); | |
162 | if (S_ISDIR(mode)) | |
163 | dget(dentry); /* pin only directory dentry in core */ | |
164 | } else | |
165 | iput(inode); | |
166 | Done: | |
167 | return error; | |
168 | } | |
169 | ||
1da177e4 LT |
170 | /* |
171 | * Get the name for corresponding element represented by the given sysfs_dirent | |
172 | */ | |
173 | const unsigned char * sysfs_get_name(struct sysfs_dirent *sd) | |
174 | { | |
175 | struct attribute * attr; | |
176 | struct bin_attribute * bin_attr; | |
177 | struct sysfs_symlink * sl; | |
178 | ||
179 | if (!sd || !sd->s_element) | |
180 | BUG(); | |
181 | ||
182 | switch (sd->s_type) { | |
183 | case SYSFS_DIR: | |
184 | /* Always have a dentry so use that */ | |
185 | return sd->s_dentry->d_name.name; | |
186 | ||
187 | case SYSFS_KOBJ_ATTR: | |
188 | attr = sd->s_element; | |
189 | return attr->name; | |
190 | ||
191 | case SYSFS_KOBJ_BIN_ATTR: | |
192 | bin_attr = sd->s_element; | |
193 | return bin_attr->attr.name; | |
194 | ||
195 | case SYSFS_KOBJ_LINK: | |
196 | sl = sd->s_element; | |
197 | return sl->link_name; | |
198 | } | |
199 | return NULL; | |
200 | } | |
201 | ||
202 | ||
203 | /* | |
204 | * Unhashes the dentry corresponding to given sysfs_dirent | |
1b1dcc1b | 205 | * Called with parent inode's i_mutex held. |
1da177e4 LT |
206 | */ |
207 | void sysfs_drop_dentry(struct sysfs_dirent * sd, struct dentry * parent) | |
208 | { | |
209 | struct dentry * dentry = sd->s_dentry; | |
210 | ||
211 | if (dentry) { | |
212 | spin_lock(&dcache_lock); | |
213 | spin_lock(&dentry->d_lock); | |
214 | if (!(d_unhashed(dentry) && dentry->d_inode)) { | |
215 | dget_locked(dentry); | |
216 | __d_drop(dentry); | |
217 | spin_unlock(&dentry->d_lock); | |
218 | spin_unlock(&dcache_lock); | |
219 | simple_unlink(parent->d_inode, dentry); | |
220 | } else { | |
221 | spin_unlock(&dentry->d_lock); | |
222 | spin_unlock(&dcache_lock); | |
223 | } | |
224 | } | |
225 | } | |
226 | ||
227 | void sysfs_hash_and_remove(struct dentry * dir, const char * name) | |
228 | { | |
229 | struct sysfs_dirent * sd; | |
230 | struct sysfs_dirent * parent_sd = dir->d_fsdata; | |
231 | ||
36676bcb JB |
232 | if (dir->d_inode == NULL) |
233 | /* no inode means this hasn't been made visible yet */ | |
234 | return; | |
235 | ||
1b1dcc1b | 236 | mutex_lock(&dir->d_inode->i_mutex); |
1da177e4 LT |
237 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { |
238 | if (!sd->s_element) | |
239 | continue; | |
240 | if (!strcmp(sysfs_get_name(sd), name)) { | |
241 | list_del_init(&sd->s_sibling); | |
242 | sysfs_drop_dentry(sd, dir); | |
243 | sysfs_put(sd); | |
244 | break; | |
245 | } | |
246 | } | |
1b1dcc1b | 247 | mutex_unlock(&dir->d_inode->i_mutex); |
1da177e4 | 248 | } |