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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Randy Dunlap16f7e0f2006-01-11 12:17:46 -080014#include <linux/capability.h>
Randy.Dunlap995982c2006-07-10 23:05:25 -070015#include <linux/errno.h>
Oliver Neukum94bebf42006-12-20 10:52:44 +010016#include <asm/semaphore.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include "sysfs.h"
18
19extern struct super_block * sysfs_sb;
20
Christoph Hellwigf5e54d62006-06-28 04:26:44 -070021static const struct address_space_operations sysfs_aops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070022 .readpage = simple_readpage,
23 .prepare_write = simple_prepare_write,
24 .commit_write = simple_commit_write
25};
26
27static struct backing_dev_info sysfs_backing_dev_info = {
28 .ra_pages = 0, /* No readahead */
29 .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
30};
31
Maneesh Soni988d1862005-05-31 10:39:14 +053032static struct inode_operations sysfs_inode_operations ={
33 .setattr = sysfs_setattr,
34};
35
Eric W. Biedermanb592fcf2007-01-24 12:35:52 -070036void sysfs_delete_inode(struct inode *inode)
37{
38 /* Free the shadowed directory inode operations */
39 if (sysfs_is_shadowed_inode(inode)) {
40 kfree(inode->i_op);
41 inode->i_op = NULL;
42 }
43 return generic_delete_inode(inode);
44}
45
Maneesh Soni988d1862005-05-31 10:39:14 +053046int sysfs_setattr(struct dentry * dentry, struct iattr * iattr)
47{
48 struct inode * inode = dentry->d_inode;
49 struct sysfs_dirent * sd = dentry->d_fsdata;
50 struct iattr * sd_iattr;
51 unsigned int ia_valid = iattr->ia_valid;
52 int error;
53
54 if (!sd)
55 return -EINVAL;
56
57 sd_iattr = sd->s_iattr;
58
59 error = inode_change_ok(inode, iattr);
60 if (error)
61 return error;
62
63 error = inode_setattr(inode, iattr);
64 if (error)
65 return error;
66
67 if (!sd_iattr) {
68 /* setting attributes for the first time, allocate now */
Eric Sesterhenn58d49282006-02-22 11:18:15 +010069 sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL);
Maneesh Soni988d1862005-05-31 10:39:14 +053070 if (!sd_iattr)
71 return -ENOMEM;
72 /* assign default attributes */
Maneesh Soni988d1862005-05-31 10:39:14 +053073 sd_iattr->ia_mode = sd->s_mode;
74 sd_iattr->ia_uid = 0;
75 sd_iattr->ia_gid = 0;
76 sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime = CURRENT_TIME;
77 sd->s_iattr = sd_iattr;
78 }
79
80 /* attributes were changed atleast once in past */
81
82 if (ia_valid & ATTR_UID)
83 sd_iattr->ia_uid = iattr->ia_uid;
84 if (ia_valid & ATTR_GID)
85 sd_iattr->ia_gid = iattr->ia_gid;
86 if (ia_valid & ATTR_ATIME)
87 sd_iattr->ia_atime = timespec_trunc(iattr->ia_atime,
88 inode->i_sb->s_time_gran);
89 if (ia_valid & ATTR_MTIME)
90 sd_iattr->ia_mtime = timespec_trunc(iattr->ia_mtime,
91 inode->i_sb->s_time_gran);
92 if (ia_valid & ATTR_CTIME)
93 sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime,
94 inode->i_sb->s_time_gran);
95 if (ia_valid & ATTR_MODE) {
96 umode_t mode = iattr->ia_mode;
97
98 if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
99 mode &= ~S_ISGID;
Maneesh Soni9ca1eb32005-07-29 12:14:19 -0700100 sd_iattr->ia_mode = sd->s_mode = mode;
Maneesh Soni988d1862005-05-31 10:39:14 +0530101 }
102
103 return error;
104}
105
Maneesh Soni82155342005-05-31 10:39:52 +0530106static inline void set_default_inode_attr(struct inode * inode, mode_t mode)
107{
108 inode->i_mode = mode;
109 inode->i_uid = 0;
110 inode->i_gid = 0;
111 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
112}
113
114static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
115{
116 inode->i_mode = iattr->ia_mode;
117 inode->i_uid = iattr->ia_uid;
118 inode->i_gid = iattr->ia_gid;
119 inode->i_atime = iattr->ia_atime;
120 inode->i_mtime = iattr->ia_mtime;
121 inode->i_ctime = iattr->ia_ctime;
122}
123
Arjan van de Ven232ba9d2006-07-12 09:03:06 -0700124
125/*
126 * sysfs has a different i_mutex lock order behavior for i_mutex than other
127 * filesystems; sysfs i_mutex is called in many places with subsystem locks
128 * held. At the same time, many of the VFS locking rules do not apply to
129 * sysfs at all (cross directory rename for example). To untangle this mess
130 * (which gives false positives in lockdep), we're giving sysfs inodes their
131 * own class for i_mutex.
132 */
133static struct lock_class_key sysfs_inode_imutex_key;
134
Maneesh Soni82155342005-05-31 10:39:52 +0530135struct inode * sysfs_new_inode(mode_t mode, struct sysfs_dirent * sd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136{
137 struct inode * inode = new_inode(sysfs_sb);
138 if (inode) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 inode->i_blocks = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 inode->i_mapping->a_ops = &sysfs_aops;
141 inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info;
Maneesh Soni82155342005-05-31 10:39:52 +0530142 inode->i_op = &sysfs_inode_operations;
Arjan van de Ven232ba9d2006-07-12 09:03:06 -0700143 lockdep_set_class(&inode->i_mutex, &sysfs_inode_imutex_key);
Maneesh Soni82155342005-05-31 10:39:52 +0530144
145 if (sd->s_iattr) {
146 /* sysfs_dirent has non-default attributes
147 * get them for the new inode from persistent copy
148 * in sysfs_dirent
149 */
150 set_inode_attr(inode, sd->s_iattr);
151 } else
152 set_default_inode_attr(inode, mode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 }
154 return inode;
155}
156
157int sysfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *))
158{
159 int error = 0;
160 struct inode * inode = NULL;
161 if (dentry) {
162 if (!dentry->d_inode) {
Maneesh Soni82155342005-05-31 10:39:52 +0530163 struct sysfs_dirent * sd = dentry->d_fsdata;
164 if ((inode = sysfs_new_inode(mode, sd))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 if (dentry->d_parent && dentry->d_parent->d_inode) {
166 struct inode *p_inode = dentry->d_parent->d_inode;
167 p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME;
168 }
169 goto Proceed;
170 }
171 else
172 error = -ENOMEM;
173 } else
174 error = -EEXIST;
175 } else
176 error = -ENOENT;
177 goto Done;
178
179 Proceed:
180 if (init)
181 error = init(inode);
182 if (!error) {
183 d_instantiate(dentry, inode);
184 if (S_ISDIR(mode))
185 dget(dentry); /* pin only directory dentry in core */
186 } else
187 iput(inode);
188 Done:
189 return error;
190}
191
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192/*
193 * Get the name for corresponding element represented by the given sysfs_dirent
194 */
195const unsigned char * sysfs_get_name(struct sysfs_dirent *sd)
196{
197 struct attribute * attr;
198 struct bin_attribute * bin_attr;
199 struct sysfs_symlink * sl;
200
Eric Sesterhenn99cee0c2006-04-01 01:18:38 +0200201 BUG_ON(!sd || !sd->s_element);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202
203 switch (sd->s_type) {
204 case SYSFS_DIR:
205 /* Always have a dentry so use that */
206 return sd->s_dentry->d_name.name;
207
208 case SYSFS_KOBJ_ATTR:
209 attr = sd->s_element;
210 return attr->name;
211
212 case SYSFS_KOBJ_BIN_ATTR:
213 bin_attr = sd->s_element;
214 return bin_attr->attr.name;
215
216 case SYSFS_KOBJ_LINK:
217 sl = sd->s_element;
218 return sl->link_name;
219 }
220 return NULL;
221}
222
Oliver Neukum94bebf42006-12-20 10:52:44 +0100223static inline void orphan_all_buffers(struct inode *node)
224{
225 struct sysfs_buffer_collection *set = node->i_private;
226 struct sysfs_buffer *buf;
227
Frederik Deweerdtd3fc3732007-01-05 12:04:33 -0800228 mutex_lock_nested(&node->i_mutex, I_MUTEX_CHILD);
Oliver Neukum94bebf42006-12-20 10:52:44 +0100229 if (node->i_private) {
230 list_for_each_entry(buf, &set->associates, associates) {
231 down(&buf->sem);
232 buf->orphaned = 1;
233 up(&buf->sem);
234 }
235 }
236 mutex_unlock(&node->i_mutex);
237}
238
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239
240/*
241 * Unhashes the dentry corresponding to given sysfs_dirent
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800242 * Called with parent inode's i_mutex held.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243 */
244void sysfs_drop_dentry(struct sysfs_dirent * sd, struct dentry * parent)
245{
246 struct dentry * dentry = sd->s_dentry;
Oliver Neukum94bebf42006-12-20 10:52:44 +0100247 struct inode *inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248
249 if (dentry) {
250 spin_lock(&dcache_lock);
251 spin_lock(&dentry->d_lock);
252 if (!(d_unhashed(dentry) && dentry->d_inode)) {
Oliver Neukum94bebf42006-12-20 10:52:44 +0100253 inode = dentry->d_inode;
254 spin_lock(&inode->i_lock);
255 __iget(inode);
256 spin_unlock(&inode->i_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 dget_locked(dentry);
258 __d_drop(dentry);
259 spin_unlock(&dentry->d_lock);
260 spin_unlock(&dcache_lock);
261 simple_unlink(parent->d_inode, dentry);
Oliver Neukum94bebf42006-12-20 10:52:44 +0100262 orphan_all_buffers(inode);
263 iput(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264 } else {
265 spin_unlock(&dentry->d_lock);
266 spin_unlock(&dcache_lock);
267 }
268 }
269}
270
Randy.Dunlap995982c2006-07-10 23:05:25 -0700271int sysfs_hash_and_remove(struct dentry * dir, const char * name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272{
273 struct sysfs_dirent * sd;
Greg Kroah-Hartman641e6f32006-03-16 15:44:26 -0800274 struct sysfs_dirent * parent_sd;
Randy.Dunlap995982c2006-07-10 23:05:25 -0700275 int found = 0;
Greg Kroah-Hartman641e6f32006-03-16 15:44:26 -0800276
277 if (!dir)
Randy.Dunlap995982c2006-07-10 23:05:25 -0700278 return -ENOENT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279
James Bottomley36676bc2005-08-26 18:34:17 -0700280 if (dir->d_inode == NULL)
281 /* no inode means this hasn't been made visible yet */
Randy.Dunlap995982c2006-07-10 23:05:25 -0700282 return -ENOENT;
James Bottomley36676bc2005-08-26 18:34:17 -0700283
Greg Kroah-Hartman641e6f32006-03-16 15:44:26 -0800284 parent_sd = dir->d_fsdata;
Frederik Deweerdtd3fc3732007-01-05 12:04:33 -0800285 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
287 if (!sd->s_element)
288 continue;
289 if (!strcmp(sysfs_get_name(sd), name)) {
290 list_del_init(&sd->s_sibling);
291 sysfs_drop_dentry(sd, dir);
292 sysfs_put(sd);
Randy.Dunlap995982c2006-07-10 23:05:25 -0700293 found = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 break;
295 }
296 }
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800297 mutex_unlock(&dir->d_inode->i_mutex);
Randy.Dunlap995982c2006-07-10 23:05:25 -0700298
299 return found ? 0 : -ENOENT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300}