summaryrefslogtreecommitdiffstats
path: root/fs/sysfs/inode.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/sysfs/inode.c')
-rw-r--r--fs/sysfs/inode.c165
1 files changed, 165 insertions, 0 deletions
diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
new file mode 100644
index 000000000000..aff7b2dfa8ee
--- /dev/null
+++ b/fs/sysfs/inode.c
@@ -0,0 +1,165 @@
+/*
+ * inode.c - basic inode and dentry operations.
+ *
+ * sysfs is Copyright (c) 2001-3 Patrick Mochel
+ *
+ * Please see Documentation/filesystems/sysfs.txt for more information.
+ */
+
+#undef DEBUG
+
+#include <linux/pagemap.h>
+#include <linux/namei.h>
+#include <linux/backing-dev.h>
+#include "sysfs.h"
+
+extern struct super_block * sysfs_sb;
+
+static struct address_space_operations sysfs_aops = {
+ .readpage = simple_readpage,
+ .prepare_write = simple_prepare_write,
+ .commit_write = simple_commit_write
+};
+
+static struct backing_dev_info sysfs_backing_dev_info = {
+ .ra_pages = 0, /* No readahead */
+ .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
+};
+
+struct inode * sysfs_new_inode(mode_t mode)
+{
+ struct inode * inode = new_inode(sysfs_sb);
+ if (inode) {
+ inode->i_mode = mode;
+ inode->i_uid = 0;
+ inode->i_gid = 0;
+ inode->i_blksize = PAGE_CACHE_SIZE;
+ inode->i_blocks = 0;
+ inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+ inode->i_mapping->a_ops = &sysfs_aops;
+ inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info;
+ }
+ return inode;
+}
+
+int sysfs_create(struct dentry * dentry, int mode, int (*init)(struct inode *))
+{
+ int error = 0;
+ struct inode * inode = NULL;
+ if (dentry) {
+ if (!dentry->d_inode) {
+ if ((inode = sysfs_new_inode(mode))) {
+ if (dentry->d_parent && dentry->d_parent->d_inode) {
+ struct inode *p_inode = dentry->d_parent->d_inode;
+ p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME;
+ }
+ goto Proceed;
+ }
+ else
+ error = -ENOMEM;
+ } else
+ error = -EEXIST;
+ } else
+ error = -ENOENT;
+ goto Done;
+
+ Proceed:
+ if (init)
+ error = init(inode);
+ if (!error) {
+ d_instantiate(dentry, inode);
+ if (S_ISDIR(mode))
+ dget(dentry); /* pin only directory dentry in core */
+ } else
+ iput(inode);
+ Done:
+ return error;
+}
+
+struct dentry * sysfs_get_dentry(struct dentry * parent, const char * name)
+{
+ struct qstr qstr;
+
+ qstr.name = name;
+ qstr.len = strlen(name);
+ qstr.hash = full_name_hash(name,qstr.len);
+ return lookup_hash(&qstr,parent);
+}
+
+/*
+ * Get the name for corresponding element represented by the given sysfs_dirent
+ */
+const unsigned char * sysfs_get_name(struct sysfs_dirent *sd)
+{
+ struct attribute * attr;
+ struct bin_attribute * bin_attr;
+ struct sysfs_symlink * sl;
+
+ if (!sd || !sd->s_element)
+ BUG();
+
+ switch (sd->s_type) {
+ case SYSFS_DIR:
+ /* Always have a dentry so use that */
+ return sd->s_dentry->d_name.name;
+
+ case SYSFS_KOBJ_ATTR:
+ attr = sd->s_element;
+ return attr->name;
+
+ case SYSFS_KOBJ_BIN_ATTR:
+ bin_attr = sd->s_element;
+ return bin_attr->attr.name;
+
+ case SYSFS_KOBJ_LINK:
+ sl = sd->s_element;
+ return sl->link_name;
+ }
+ return NULL;
+}
+
+
+/*
+ * Unhashes the dentry corresponding to given sysfs_dirent
+ * Called with parent inode's i_sem held.
+ */
+void sysfs_drop_dentry(struct sysfs_dirent * sd, struct dentry * parent)
+{
+ struct dentry * dentry = sd->s_dentry;
+
+ if (dentry) {
+ spin_lock(&dcache_lock);
+ spin_lock(&dentry->d_lock);
+ if (!(d_unhashed(dentry) && dentry->d_inode)) {
+ dget_locked(dentry);
+ __d_drop(dentry);
+ spin_unlock(&dentry->d_lock);
+ spin_unlock(&dcache_lock);
+ simple_unlink(parent->d_inode, dentry);
+ } else {
+ spin_unlock(&dentry->d_lock);
+ spin_unlock(&dcache_lock);
+ }
+ }
+}
+
+void sysfs_hash_and_remove(struct dentry * dir, const char * name)
+{
+ struct sysfs_dirent * sd;
+ struct sysfs_dirent * parent_sd = dir->d_fsdata;
+
+ down(&dir->d_inode->i_sem);
+ list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
+ if (!sd->s_element)
+ continue;
+ if (!strcmp(sysfs_get_name(sd), name)) {
+ list_del_init(&sd->s_sibling);
+ sysfs_drop_dentry(sd, dir);
+ sysfs_put(sd);
+ break;
+ }
+ }
+ up(&dir->d_inode->i_sem);
+}
+
+