From: Maneesh Soni <maneesh@in.ibm.com>
o This patch implements the sysfs_dir_operations file_operations strucutre for
sysfs directories. It uses the sysfs_dirent based tree for ->readdir() and
->lseek() methods instead of simple_dir_operations which use dentry based
tree.
o This also has the code for sysfs_get() and sysfs_put() which manipulates
the reference counting for for sysfs_dirents.
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/fs/sysfs/dir.c | 173 ++++++++++++++++++++++++++++++++++++++++++++++-
25-akpm/fs/sysfs/mount.c | 2
25-akpm/fs/sysfs/sysfs.h | 27 +++++++
3 files changed, 200 insertions(+), 2 deletions(-)
diff -puN fs/sysfs/dir.c~sysfs-backing-store-use-sysfs_dirent-tree-for-readdir-etc fs/sysfs/dir.c
--- 25/fs/sysfs/dir.c~sysfs-backing-store-use-sysfs_dirent-tree-for-readdir-etc Thu Jul 29 13:59:51 2004
+++ 25-akpm/fs/sysfs/dir.c Thu Jul 29 13:59:51 2004
@@ -15,7 +15,7 @@ DECLARE_RWSEM(sysfs_rename_sem);
static int init_dir(struct inode * inode)
{
inode->i_op = &simple_dir_inode_operations;
- inode->i_fop = &simple_dir_operations;
+ inode->i_fop = &sysfs_dir_operations;
/* directory inodes start off with i_nlink == 2 (for "." entry) */
inode->i_nlink++;
@@ -210,6 +210,177 @@ int sysfs_rename_dir(struct kobject * ko
return error;
}
+/* 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_KOBJECT:
+ case SYSFS_KOBJ_ATTR_GROUP:
+ /* 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;
+}
+
+static int sysfs_dir_open(struct inode *inode, struct file *file)
+{
+ struct dentry * dentry = file->f_dentry;
+ struct sysfs_dirent * parent_sd = dentry->d_fsdata;
+
+ down(&dentry->d_inode->i_sem);
+ file->private_data = sysfs_new_dirent(parent_sd, NULL, 0);
+ up(&dentry->d_inode->i_sem);
+
+ return file->private_data ? 0 : -ENOMEM;
+
+}
+
+static int sysfs_dir_close(struct inode *inode, struct file *file)
+{
+ struct dentry * dentry = file->f_dentry;
+ struct sysfs_dirent * cursor = file->private_data;
+
+ down(&dentry->d_inode->i_sem);
+ list_del_init(&cursor->s_sibling);
+ up(&dentry->d_inode->i_sem);
+ sysfs_put(file->private_data);
+
+ return 0;
+}
+
+/* Relationship between s_mode and the DT_xxx types */
+static inline unsigned char dt_type(struct sysfs_dirent *sd)
+{
+ return (sd->s_mode >> 12) & 15;
+}
+
+static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
+{
+ struct dentry *dentry = filp->f_dentry;
+ struct sysfs_dirent * parent_sd = dentry->d_fsdata;
+ struct sysfs_dirent *cursor = filp->private_data;
+ struct list_head *p, *q = &cursor->s_sibling;
+ ino_t ino;
+ int i = filp->f_pos;
+
+ switch (i) {
+ case 0:
+ ino = dentry->d_inode->i_ino;
+ if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
+ break;
+ filp->f_pos++;
+ i++;
+ /* fallthrough */
+ case 1:
+ ino = parent_ino(dentry);
+ if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
+ break;
+ filp->f_pos++;
+ i++;
+ /* fallthrough */
+ default:
+ if (filp->f_pos == 2) {
+ list_del(q);
+ list_add(q, &parent_sd->s_children);
+ }
+ for (p=q->next; p!= &parent_sd->s_children; p=p->next) {
+ struct sysfs_dirent *next;
+ const char * name;
+ int len;
+
+ next = list_entry(p, struct sysfs_dirent,
+ s_sibling);
+ if (!next->s_element)
+ continue;
+
+ name = sysfs_get_name(next);
+ len = strlen(name);
+ if (next->s_dentry)
+ ino = next->s_dentry->d_inode->i_ino;
+ else
+ ino = iunique(sysfs_sb, 2);
+
+ if (filldir(dirent, name, len, filp->f_pos, ino,
+ dt_type(next)) < 0)
+ return 0;
+
+ list_del(q);
+ list_add(q, p);
+ p = q;
+ filp->f_pos++;
+ }
+ }
+ return 0;
+}
+
+static loff_t sysfs_dir_lseek(struct file * file, loff_t offset, int origin)
+{
+ struct dentry * dentry = file->f_dentry;
+
+ down(&dentry->d_inode->i_sem);
+ switch (origin) {
+ case 1:
+ offset += file->f_pos;
+ case 0:
+ if (offset >= 0)
+ break;
+ default:
+ up(&file->f_dentry->d_inode->i_sem);
+ return -EINVAL;
+ }
+ if (offset != file->f_pos) {
+ file->f_pos = offset;
+ if (file->f_pos >= 2) {
+ struct sysfs_dirent *sd = dentry->d_fsdata;
+ struct sysfs_dirent *cursor = file->private_data;
+ struct list_head *p;
+ loff_t n = file->f_pos - 2;
+
+ list_del(&cursor->s_sibling);
+ p = sd->s_children.next;
+ while (n && p != &sd->s_children) {
+ struct sysfs_dirent *next;
+ next = list_entry(p, struct sysfs_dirent,
+ s_sibling);
+ if (next->s_element)
+ n--;
+ p = p->next;
+ }
+ list_add_tail(&cursor->s_sibling, p);
+ }
+ }
+ up(&dentry->d_inode->i_sem);
+ return offset;
+}
+
+struct file_operations sysfs_dir_operations = {
+ .open = sysfs_dir_open,
+ .release = sysfs_dir_close,
+ .llseek = sysfs_dir_lseek,
+ .read = generic_read_dir,
+ .readdir = sysfs_readdir,
+};
+
EXPORT_SYMBOL(sysfs_create_dir);
EXPORT_SYMBOL(sysfs_remove_dir);
EXPORT_SYMBOL(sysfs_rename_dir);
diff -puN fs/sysfs/mount.c~sysfs-backing-store-use-sysfs_dirent-tree-for-readdir-etc fs/sysfs/mount.c
--- 25/fs/sysfs/mount.c~sysfs-backing-store-use-sysfs_dirent-tree-for-readdir-etc Thu Jul 29 13:59:51 2004
+++ 25-akpm/fs/sysfs/mount.c Thu Jul 29 13:59:51 2004
@@ -43,7 +43,7 @@ static int sysfs_fill_super(struct super
inode = sysfs_new_inode(S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO);
if (inode) {
inode->i_op = &simple_dir_inode_operations;
- inode->i_fop = &simple_dir_operations;
+ inode->i_fop = &sysfs_dir_operations;
/* directory inodes start off with i_nlink == 2 (for "." entry) */
inode->i_nlink++;
} else {
diff -puN fs/sysfs/sysfs.h~sysfs-backing-store-use-sysfs_dirent-tree-for-readdir-etc fs/sysfs/sysfs.h
--- 25/fs/sysfs/sysfs.h~sysfs-backing-store-use-sysfs_dirent-tree-for-readdir-etc Thu Jul 29 13:59:51 2004
+++ 25-akpm/fs/sysfs/sysfs.h Thu Jul 29 13:59:51 2004
@@ -4,6 +4,8 @@ extern struct vfsmount * sysfs_mount;
extern struct inode * sysfs_new_inode(mode_t mode);
extern int sysfs_create(struct dentry *, int mode, int (*init)(struct inode *));
+
+extern const unsigned char * sysfs_get_name(struct sysfs_dirent *sd);
extern struct dentry * sysfs_get_dentry(struct dentry *, const char *);
extern void sysfs_drop_dentry(struct sysfs_dirent *, struct dentry *);
@@ -16,6 +18,8 @@ extern void sysfs_remove_subdir(struct d
extern int sysfs_readlink(struct dentry *, char __user *, int );
extern int sysfs_follow_link(struct dentry *, struct nameidata *);
extern struct rw_semaphore sysfs_rename_sem;
+extern struct super_block * sysfs_sb;
+extern struct file_operations sysfs_dir_operations;
struct sysfs_symlink {
char * link_name;
@@ -58,3 +62,26 @@ struct sysfs_dirent * sysfs_new_dirent(s
return sd;
}
+
+static inline struct sysfs_dirent * sysfs_get(struct sysfs_dirent * sd)
+{
+ if (sd) {
+ WARN_ON(!atomic_read(&sd->s_count));
+ atomic_inc(&sd->s_count);
+ }
+ return sd;
+}
+
+static inline void sysfs_put(struct sysfs_dirent * sd)
+{
+ if (atomic_dec_and_test(&sd->s_count)) {
+ if (sd->s_type & SYSFS_KOBJ_LINK) {
+ struct sysfs_symlink * sl = sd->s_element;
+ kfree(sl->link_name);
+ kobject_put(sl->target_kobj);
+ kfree(sl);
+ }
+ kfree(sd);
+ }
+}
+
_