Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
6d66f5cd | 2 | * fs/sysfs/inode.c - basic sysfs inode and dentry operations |
1da177e4 | 3 | * |
6d66f5cd TH |
4 | * Copyright (c) 2001-3 Patrick Mochel |
5 | * Copyright (c) 2007 SUSE Linux Products GmbH | |
6 | * Copyright (c) 2007 Tejun Heo <teheo@suse.de> | |
7 | * | |
8 | * This file is released under the GPLv2. | |
1da177e4 LT |
9 | * |
10 | * Please see Documentation/filesystems/sysfs.txt for more information. | |
11 | */ | |
12 | ||
13 | #undef DEBUG | |
14 | ||
15 | #include <linux/pagemap.h> | |
16 | #include <linux/namei.h> | |
17 | #include <linux/backing-dev.h> | |
16f7e0fe | 18 | #include <linux/capability.h> |
995982ca | 19 | #include <linux/errno.h> |
e8edc6e0 | 20 | #include <linux/sched.h> |
1da177e4 LT |
21 | #include "sysfs.h" |
22 | ||
23 | extern struct super_block * sysfs_sb; | |
24 | ||
f5e54d6e | 25 | static const struct address_space_operations sysfs_aops = { |
1da177e4 | 26 | .readpage = simple_readpage, |
800d15a5 NP |
27 | .write_begin = simple_write_begin, |
28 | .write_end = simple_write_end, | |
1da177e4 LT |
29 | }; |
30 | ||
31 | static struct backing_dev_info sysfs_backing_dev_info = { | |
32 | .ra_pages = 0, /* No readahead */ | |
e4ad08fe | 33 | .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, |
1da177e4 LT |
34 | }; |
35 | ||
c5ef1c42 | 36 | static const struct inode_operations sysfs_inode_operations ={ |
988d186d MS |
37 | .setattr = sysfs_setattr, |
38 | }; | |
39 | ||
e0bf68dd PZ |
40 | int __init sysfs_inode_init(void) |
41 | { | |
42 | return bdi_init(&sysfs_backing_dev_info); | |
43 | } | |
44 | ||
988d186d MS |
45 | int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) |
46 | { | |
47 | struct inode * inode = dentry->d_inode; | |
48 | struct sysfs_dirent * sd = dentry->d_fsdata; | |
49 | struct iattr * sd_iattr; | |
50 | unsigned int ia_valid = iattr->ia_valid; | |
51 | int error; | |
52 | ||
53 | if (!sd) | |
54 | return -EINVAL; | |
55 | ||
56 | sd_iattr = sd->s_iattr; | |
57 | ||
58 | error = inode_change_ok(inode, iattr); | |
59 | if (error) | |
60 | return error; | |
61 | ||
40a2159a BH |
62 | iattr->ia_valid &= ~ATTR_SIZE; /* ignore size changes */ |
63 | ||
988d186d MS |
64 | error = inode_setattr(inode, iattr); |
65 | if (error) | |
66 | return error; | |
67 | ||
68 | if (!sd_iattr) { | |
69 | /* setting attributes for the first time, allocate now */ | |
58d49283 | 70 | sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL); |
988d186d MS |
71 | if (!sd_iattr) |
72 | return -ENOMEM; | |
73 | /* assign default attributes */ | |
988d186d MS |
74 | sd_iattr->ia_mode = sd->s_mode; |
75 | sd_iattr->ia_uid = 0; | |
76 | sd_iattr->ia_gid = 0; | |
77 | sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime = CURRENT_TIME; | |
78 | sd->s_iattr = sd_iattr; | |
79 | } | |
80 | ||
81 | /* attributes were changed atleast once in past */ | |
82 | ||
83 | if (ia_valid & ATTR_UID) | |
84 | sd_iattr->ia_uid = iattr->ia_uid; | |
85 | if (ia_valid & ATTR_GID) | |
86 | sd_iattr->ia_gid = iattr->ia_gid; | |
87 | if (ia_valid & ATTR_ATIME) | |
88 | sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime, | |
89 | inode->i_sb->s_time_gran); | |
90 | if (ia_valid & ATTR_MTIME) | |
91 | sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime, | |
92 | inode->i_sb->s_time_gran); | |
93 | if (ia_valid & ATTR_CTIME) | |
94 | sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime, | |
95 | inode->i_sb->s_time_gran); | |
96 | if (ia_valid & ATTR_MODE) { | |
97 | umode_t mode = iattr->ia_mode; | |
98 | ||
99 | if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) | |
100 | mode &= ~S_ISGID; | |
9ca1eb32 | 101 | sd_iattr->ia_mode = sd->s_mode = mode; |
988d186d MS |
102 | } |
103 | ||
104 | return error; | |
105 | } | |
106 | ||
8215534c MS |
107 | static inline void set_default_inode_attr(struct inode * inode, mode_t mode) |
108 | { | |
109 | inode->i_mode = mode; | |
110 | inode->i_uid = 0; | |
111 | inode->i_gid = 0; | |
112 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
113 | } | |
114 | ||
115 | static inline void set_inode_attr(struct inode * inode, struct iattr * iattr) | |
116 | { | |
117 | inode->i_mode = iattr->ia_mode; | |
118 | inode->i_uid = iattr->ia_uid; | |
119 | inode->i_gid = iattr->ia_gid; | |
120 | inode->i_atime = iattr->ia_atime; | |
121 | inode->i_mtime = iattr->ia_mtime; | |
122 | inode->i_ctime = iattr->ia_ctime; | |
123 | } | |
124 | ||
232ba9db AV |
125 | |
126 | /* | |
127 | * sysfs has a different i_mutex lock order behavior for i_mutex than other | |
128 | * filesystems; sysfs i_mutex is called in many places with subsystem locks | |
129 | * held. At the same time, many of the VFS locking rules do not apply to | |
130 | * sysfs at all (cross directory rename for example). To untangle this mess | |
131 | * (which gives false positives in lockdep), we're giving sysfs inodes their | |
132 | * own class for i_mutex. | |
133 | */ | |
134 | static struct lock_class_key sysfs_inode_imutex_key; | |
135 | ||
372e88bd EB |
136 | static int sysfs_count_nlink(struct sysfs_dirent *sd) |
137 | { | |
138 | struct sysfs_dirent *child; | |
139 | int nr = 0; | |
140 | ||
bc747f37 | 141 | for (child = sd->s_dir.children; child; child = child->s_sibling) |
372e88bd EB |
142 | if (sysfs_type(child) == SYSFS_DIR) |
143 | nr++; | |
144 | ||
145 | return nr + 2; | |
146 | } | |
147 | ||
bc37e283 | 148 | static void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode) |
1da177e4 | 149 | { |
372e88bd EB |
150 | struct bin_attribute *bin_attr; |
151 | ||
fc9f54b9 TH |
152 | inode->i_blocks = 0; |
153 | inode->i_mapping->a_ops = &sysfs_aops; | |
154 | inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info; | |
155 | inode->i_op = &sysfs_inode_operations; | |
156 | inode->i_ino = sd->s_ino; | |
157 | lockdep_set_class(&inode->i_mutex, &sysfs_inode_imutex_key); | |
158 | ||
159 | if (sd->s_iattr) { | |
160 | /* sysfs_dirent has non-default attributes | |
161 | * get them for the new inode from persistent copy | |
162 | * in sysfs_dirent | |
163 | */ | |
164 | set_inode_attr(inode, sd->s_iattr); | |
165 | } else | |
166 | set_default_inode_attr(inode, sd->s_mode); | |
372e88bd EB |
167 | |
168 | ||
169 | /* initialize inode according to type */ | |
170 | switch (sysfs_type(sd)) { | |
372e88bd EB |
171 | case SYSFS_DIR: |
172 | inode->i_op = &sysfs_dir_inode_operations; | |
173 | inode->i_fop = &sysfs_dir_operations; | |
174 | inode->i_nlink = sysfs_count_nlink(sd); | |
175 | break; | |
176 | case SYSFS_KOBJ_ATTR: | |
177 | inode->i_size = PAGE_SIZE; | |
178 | inode->i_fop = &sysfs_file_operations; | |
179 | break; | |
180 | case SYSFS_KOBJ_BIN_ATTR: | |
b1fc3d61 | 181 | bin_attr = sd->s_bin_attr.bin_attr; |
372e88bd EB |
182 | inode->i_size = bin_attr->size; |
183 | inode->i_fop = &bin_fops; | |
184 | break; | |
185 | case SYSFS_KOBJ_LINK: | |
186 | inode->i_op = &sysfs_symlink_inode_operations; | |
187 | break; | |
188 | default: | |
189 | BUG(); | |
190 | } | |
191 | ||
192 | unlock_new_inode(inode); | |
fc9f54b9 TH |
193 | } |
194 | ||
195 | /** | |
8312a8d7 | 196 | * sysfs_get_inode - get inode for sysfs_dirent |
fc9f54b9 TH |
197 | * @sd: sysfs_dirent to allocate inode for |
198 | * | |
8312a8d7 TH |
199 | * Get inode for @sd. If such inode doesn't exist, a new inode |
200 | * is allocated and basics are initialized. New inode is | |
201 | * returned locked. | |
fc9f54b9 TH |
202 | * |
203 | * LOCKING: | |
204 | * Kernel thread context (may sleep). | |
205 | * | |
206 | * RETURNS: | |
207 | * Pointer to allocated inode on success, NULL on failure. | |
208 | */ | |
8312a8d7 | 209 | struct inode * sysfs_get_inode(struct sysfs_dirent *sd) |
fc9f54b9 TH |
210 | { |
211 | struct inode *inode; | |
212 | ||
8312a8d7 TH |
213 | inode = iget_locked(sysfs_sb, sd->s_ino); |
214 | if (inode && (inode->i_state & I_NEW)) | |
fc9f54b9 TH |
215 | sysfs_init_inode(sd, inode); |
216 | ||
1da177e4 LT |
217 | return inode; |
218 | } | |
219 | ||
608e266a | 220 | int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name) |
1da177e4 | 221 | { |
fb6896da | 222 | struct sysfs_addrm_cxt acxt; |
41fc1c27 | 223 | struct sysfs_dirent *sd; |
641e6f30 | 224 | |
608e266a | 225 | if (!dir_sd) |
995982ca | 226 | return -ENOENT; |
1da177e4 | 227 | |
fb6896da | 228 | sysfs_addrm_start(&acxt, dir_sd); |
608e266a | 229 | |
41fc1c27 TH |
230 | sd = sysfs_find_dirent(dir_sd, name); |
231 | if (sd) | |
232 | sysfs_remove_one(&acxt, sd); | |
3007e997 | 233 | |
990e53f8 TH |
234 | sysfs_addrm_finish(&acxt); |
235 | ||
236 | if (sd) | |
fb6896da | 237 | return 0; |
990e53f8 TH |
238 | else |
239 | return -ENOENT; | |
1da177e4 | 240 | } |