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> | |
14 | #include "sysfs.h" | |
15 | ||
16 | extern struct super_block * sysfs_sb; | |
17 | ||
18 | static struct address_space_operations sysfs_aops = { | |
19 | .readpage = simple_readpage, | |
20 | .prepare_write = simple_prepare_write, | |
21 | .commit_write = simple_commit_write | |
22 | }; | |
23 | ||
24 | static struct backing_dev_info sysfs_backing_dev_info = { | |
25 | .ra_pages = 0, /* No readahead */ | |
26 | .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK, | |
27 | }; | |
28 | ||
988d186d MS |
29 | static struct inode_operations sysfs_inode_operations ={ |
30 | .setattr = sysfs_setattr, | |
31 | }; | |
32 | ||
33 | int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) | |
34 | { | |
35 | struct inode * inode = dentry->d_inode; | |
36 | struct sysfs_dirent * sd = dentry->d_fsdata; | |
37 | struct iattr * sd_iattr; | |
38 | unsigned int ia_valid = iattr->ia_valid; | |
39 | int error; | |
40 | ||
41 | if (!sd) | |
42 | return -EINVAL; | |
43 | ||
44 | sd_iattr = sd->s_iattr; | |
45 | ||
46 | error = inode_change_ok(inode, iattr); | |
47 | if (error) | |
48 | return error; | |
49 | ||
50 | error = inode_setattr(inode, iattr); | |
51 | if (error) | |
52 | return error; | |
53 | ||
54 | if (!sd_iattr) { | |
55 | /* setting attributes for the first time, allocate now */ | |
56 | sd_iattr = kmalloc(sizeof(struct iattr), GFP_KERNEL); | |
57 | if (!sd_iattr) | |
58 | return -ENOMEM; | |
59 | /* assign default attributes */ | |
60 | memset(sd_iattr, 0, sizeof(struct iattr)); | |
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; | |
88 | sd_iattr->ia_mode = mode; | |
89 | } | |
90 | ||
91 | return error; | |
92 | } | |
93 | ||
1da177e4 LT |
94 | struct inode * sysfs_new_inode(mode_t mode) |
95 | { | |
96 | struct inode * inode = new_inode(sysfs_sb); | |
97 | if (inode) { | |
98 | inode->i_mode = mode; | |
99 | inode->i_uid = 0; | |
100 | inode->i_gid = 0; | |
101 | inode->i_blksize = PAGE_CACHE_SIZE; | |
102 | inode->i_blocks = 0; | |
103 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
104 | inode->i_mapping->a_ops = &sysfs_aops; | |
105 | inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info; | |
106 | } | |
107 | return inode; | |
108 | } | |
109 | ||
110 | int sysfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *)) | |
111 | { | |
112 | int error = 0; | |
113 | struct inode * inode = NULL; | |
114 | if (dentry) { | |
115 | if (!dentry->d_inode) { | |
116 | if ((inode = sysfs_new_inode(mode))) { | |
117 | if (dentry->d_parent && dentry->d_parent->d_inode) { | |
118 | struct inode *p_inode = dentry->d_parent->d_inode; | |
119 | p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME; | |
120 | } | |
121 | goto Proceed; | |
122 | } | |
123 | else | |
124 | error = -ENOMEM; | |
125 | } else | |
126 | error = -EEXIST; | |
127 | } else | |
128 | error = -ENOENT; | |
129 | goto Done; | |
130 | ||
131 | Proceed: | |
132 | if (init) | |
133 | error = init(inode); | |
134 | if (!error) { | |
135 | d_instantiate(dentry, inode); | |
136 | if (S_ISDIR(mode)) | |
137 | dget(dentry); /* pin only directory dentry in core */ | |
138 | } else | |
139 | iput(inode); | |
140 | Done: | |
141 | return error; | |
142 | } | |
143 | ||
144 | struct dentry * sysfs_get_dentry(struct dentry * parent, const char * name) | |
145 | { | |
146 | struct qstr qstr; | |
147 | ||
148 | qstr.name = name; | |
149 | qstr.len = strlen(name); | |
150 | qstr.hash = full_name_hash(name,qstr.len); | |
151 | return lookup_hash(&qstr,parent); | |
152 | } | |
153 | ||
154 | /* | |
155 | * Get the name for corresponding element represented by the given sysfs_dirent | |
156 | */ | |
157 | const unsigned char * sysfs_get_name(struct sysfs_dirent *sd) | |
158 | { | |
159 | struct attribute * attr; | |
160 | struct bin_attribute * bin_attr; | |
161 | struct sysfs_symlink * sl; | |
162 | ||
163 | if (!sd || !sd->s_element) | |
164 | BUG(); | |
165 | ||
166 | switch (sd->s_type) { | |
167 | case SYSFS_DIR: | |
168 | /* Always have a dentry so use that */ | |
169 | return sd->s_dentry->d_name.name; | |
170 | ||
171 | case SYSFS_KOBJ_ATTR: | |
172 | attr = sd->s_element; | |
173 | return attr->name; | |
174 | ||
175 | case SYSFS_KOBJ_BIN_ATTR: | |
176 | bin_attr = sd->s_element; | |
177 | return bin_attr->attr.name; | |
178 | ||
179 | case SYSFS_KOBJ_LINK: | |
180 | sl = sd->s_element; | |
181 | return sl->link_name; | |
182 | } | |
183 | return NULL; | |
184 | } | |
185 | ||
186 | ||
187 | /* | |
188 | * Unhashes the dentry corresponding to given sysfs_dirent | |
189 | * Called with parent inode's i_sem held. | |
190 | */ | |
191 | void sysfs_drop_dentry(struct sysfs_dirent * sd, struct dentry * parent) | |
192 | { | |
193 | struct dentry * dentry = sd->s_dentry; | |
194 | ||
195 | if (dentry) { | |
196 | spin_lock(&dcache_lock); | |
197 | spin_lock(&dentry->d_lock); | |
198 | if (!(d_unhashed(dentry) && dentry->d_inode)) { | |
199 | dget_locked(dentry); | |
200 | __d_drop(dentry); | |
201 | spin_unlock(&dentry->d_lock); | |
202 | spin_unlock(&dcache_lock); | |
203 | simple_unlink(parent->d_inode, dentry); | |
204 | } else { | |
205 | spin_unlock(&dentry->d_lock); | |
206 | spin_unlock(&dcache_lock); | |
207 | } | |
208 | } | |
209 | } | |
210 | ||
211 | void sysfs_hash_and_remove(struct dentry * dir, const char * name) | |
212 | { | |
213 | struct sysfs_dirent * sd; | |
214 | struct sysfs_dirent * parent_sd = dir->d_fsdata; | |
215 | ||
216 | down(&dir->d_inode->i_sem); | |
217 | list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { | |
218 | if (!sd->s_element) | |
219 | continue; | |
220 | if (!strcmp(sysfs_get_name(sd), name)) { | |
221 | list_del_init(&sd->s_sibling); | |
222 | sysfs_drop_dentry(sd, dir); | |
223 | sysfs_put(sd); | |
224 | break; | |
225 | } | |
226 | } | |
227 | up(&dir->d_inode->i_sem); | |
228 | } | |
229 | ||
230 |