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 struct inode * sysfs_new_inode(mode_t mode)
31 struct inode * inode = new_inode(sysfs_sb);
36 inode->i_blksize = PAGE_CACHE_SIZE;
38 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
39 inode->i_mapping->a_ops = &sysfs_aops;
40 inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info;
45 int sysfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *))
48 struct inode * inode = NULL;
50 if (!dentry->d_inode) {
51 if ((inode = sysfs_new_inode(mode))) {
52 if (dentry->d_parent && dentry->d_parent->d_inode) {
53 struct inode *p_inode = dentry->d_parent->d_inode;
54 p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME;
70 d_instantiate(dentry, inode);
72 dget(dentry); /* pin only directory dentry in core */
79 struct dentry * sysfs_get_dentry(struct dentry * parent, const char * name)
84 qstr.len = strlen(name);
85 qstr.hash = full_name_hash(name,qstr.len);
86 return lookup_hash(&qstr,parent);
90 * Get the name for corresponding element represented by the given sysfs_dirent
92 const unsigned char * sysfs_get_name(struct sysfs_dirent *sd)
94 struct attribute * attr;
95 struct bin_attribute * bin_attr;
96 struct sysfs_symlink * sl;
98 if (!sd || !sd->s_element)
101 switch (sd->s_type) {
103 /* Always have a dentry so use that */
104 return sd->s_dentry->d_name.name;
106 case SYSFS_KOBJ_ATTR:
107 attr = sd->s_element;
110 case SYSFS_KOBJ_BIN_ATTR:
111 bin_attr = sd->s_element;
112 return bin_attr->attr.name;
114 case SYSFS_KOBJ_LINK:
116 return sl->link_name;
123 * Unhashes the dentry corresponding to given sysfs_dirent
124 * Called with parent inode's i_sem held.
126 void sysfs_drop_dentry(struct sysfs_dirent * sd, struct dentry * parent)
128 struct dentry * dentry = sd->s_dentry;
131 spin_lock(&dcache_lock);
132 spin_lock(&dentry->d_lock);
133 if (!(d_unhashed(dentry) && dentry->d_inode)) {
136 spin_unlock(&dentry->d_lock);
137 spin_unlock(&dcache_lock);
138 simple_unlink(parent->d_inode, dentry);
140 spin_unlock(&dentry->d_lock);
141 spin_unlock(&dcache_lock);
146 void sysfs_hash_and_remove(struct dentry * dir, const char * name)
148 struct sysfs_dirent * sd;
149 struct sysfs_dirent * parent_sd = dir->d_fsdata;
151 down(&dir->d_inode->i_sem);
152 list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
155 if (!strcmp(sysfs_get_name(sd), name)) {
156 list_del_init(&sd->s_sibling);
157 sysfs_drop_dentry(sd, dir);
162 up(&dir->d_inode->i_sem);