2 * inode.c - basic inode and dentry operations.
4 * sysfs is Copyright (c) 2001-3 Patrick Mochel
6 * Please see Documentation/filesystems/sysfs.txt for more information.
11 #include <linux/pagemap.h>
12 #include <linux/namei.h>
13 #include <linux/backing-dev.h>
16 extern struct super_block * sysfs_sb;
18 static struct address_space_operations sysfs_aops = {
19 .readpage = simple_readpage,
20 .prepare_write = simple_prepare_write,
21 .commit_write = simple_commit_write
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,
29 static struct inode_operations sysfs_inode_operations ={
30 .setattr = sysfs_setattr,
33 int sysfs_setattr(struct dentry * dentry, struct iattr * iattr)
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;
44 sd_iattr = sd->s_iattr;
46 error = inode_change_ok(inode, iattr);
50 error = inode_setattr(inode, iattr);
55 /* setting attributes for the first time, allocate now */
56 sd_iattr = kmalloc(sizeof(struct iattr), GFP_KERNEL);
59 /* assign default attributes */
60 memset(sd_iattr, 0, sizeof(struct iattr));
61 sd_iattr->ia_mode = sd->s_mode;
64 sd_iattr->ia_atime = sd_iattr->ia_mtime = sd_iattr->ia_ctime = CURRENT_TIME;
65 sd->s_iattr = sd_iattr;
68 /* attributes were changed atleast once in past */
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;
86 if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
88 sd_iattr->ia_mode = mode;
94 struct inode * sysfs_new_inode(mode_t mode)
96 struct inode * inode = new_inode(sysfs_sb);
101 inode->i_blksize = PAGE_CACHE_SIZE;
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;
110 int sysfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *))
113 struct inode * inode = NULL;
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;
135 d_instantiate(dentry, inode);
137 dget(dentry); /* pin only directory dentry in core */
144 struct dentry * sysfs_get_dentry(struct dentry * parent, const char * name)
149 qstr.len = strlen(name);
150 qstr.hash = full_name_hash(name,qstr.len);
151 return lookup_hash(&qstr,parent);
155 * Get the name for corresponding element represented by the given sysfs_dirent
157 const unsigned char * sysfs_get_name(struct sysfs_dirent *sd)
159 struct attribute * attr;
160 struct bin_attribute * bin_attr;
161 struct sysfs_symlink * sl;
163 if (!sd || !sd->s_element)
166 switch (sd->s_type) {
168 /* Always have a dentry so use that */
169 return sd->s_dentry->d_name.name;
171 case SYSFS_KOBJ_ATTR:
172 attr = sd->s_element;
175 case SYSFS_KOBJ_BIN_ATTR:
176 bin_attr = sd->s_element;
177 return bin_attr->attr.name;
179 case SYSFS_KOBJ_LINK:
181 return sl->link_name;
188 * Unhashes the dentry corresponding to given sysfs_dirent
189 * Called with parent inode's i_sem held.
191 void sysfs_drop_dentry(struct sysfs_dirent * sd, struct dentry * parent)
193 struct dentry * dentry = sd->s_dentry;
196 spin_lock(&dcache_lock);
197 spin_lock(&dentry->d_lock);
198 if (!(d_unhashed(dentry) && dentry->d_inode)) {
201 spin_unlock(&dentry->d_lock);
202 spin_unlock(&dcache_lock);
203 simple_unlink(parent->d_inode, dentry);
205 spin_unlock(&dentry->d_lock);
206 spin_unlock(&dcache_lock);
211 void sysfs_hash_and_remove(struct dentry * dir, const char * name)
213 struct sysfs_dirent * sd;
214 struct sysfs_dirent * parent_sd = dir->d_fsdata;
216 down(&dir->d_inode->i_sem);
217 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
220 if (!strcmp(sysfs_get_name(sd), name)) {
221 list_del_init(&sd->s_sibling);
222 sysfs_drop_dentry(sd, dir);
227 up(&dir->d_inode->i_sem);