[RFC 3/5] sysfs backing store (leaves only) - sysfs-leaves-file.patch

Maneesh Soni
2003-12-29T09:37:17Z

o sysfs_create_file() will just link a new sysfs_dirent() structure representing
the attribute file to the kobject's s_children list.

o in sysfs_create() we take extra ref. only for dentries corresponding to
non-regular files or in other words pin only non-leaf dentries.

fs/sysfs/file.c | 63 +++++++++++++++++++++++++------------------------------
fs/sysfs/inode.c | 19 +++++++++++++---
2 files changed, 45 insertions(+), 37 deletions(-)

diff -puN fs/sysfs/file.c~sysfs-leaves-file fs/sysfs/file.c
--- linux-2.6.0/fs/sysfs/file.c~sysfs-leaves-file 2003-12-29 12:43:44.000000000 +0530
+++ linux-2.6.0-maneesh/fs/sysfs/file.c 2003-12-29 12:43:44.000000000 +0530
@@ -9,14 +9,6 @@

#include "sysfs.h"

-static struct file_operations sysfs_file_operations;
-
-static int init_file(struct inode * inode)
-{
- inode->i_size = PAGE_SIZE;
- inode->i_fop = &sysfs_file_operations;
- return 0;
-}

#define to_subsys(k) container_of(k,struct subsystem,kset.kobj)
#define to_sattr(a) container_of(a,struct subsys_attribute,attr)
@@ -77,8 +69,10 @@ struct sysfs_buffer {
*/
static int fill_read_buffer(struct file * file, struct sysfs_buffer * buffer)
{
- struct attribute * attr = file->f_dentry->d_fsdata;
- struct kobject * kobj = file->f_dentry->d_parent->d_fsdata;
+ struct sysfs_dirent * sd_attr = file->f_dentry->d_fsdata;
+ struct attribute * attr = sd_attr->s_element;
+ struct sysfs_dirent * sd_kobj = file->f_dentry->d_parent->d_fsdata;
+ struct kobject * kobj = sd_kobj->s_element;
struct sysfs_ops * ops = buffer->ops;
int ret = 0;
ssize_t count;
@@ -198,8 +192,10 @@ fill_write_buffer(struct sysfs_buffer *
static int
flush_write_buffer(struct file * file, struct sysfs_buffer * buffer, size_t count)
{
- struct attribute * attr = file->f_dentry->d_fsdata;
- struct kobject * kobj = file->f_dentry->d_parent->d_fsdata;
+ struct sysfs_dirent * sd_attr = file->f_dentry->d_fsdata;
+ struct attribute * attr = sd_attr->s_element;
+ struct sysfs_dirent * sd_kobj = file->f_dentry->d_parent->d_fsdata;
+ struct kobject * kobj = sd_kobj->s_element;
struct sysfs_ops * ops = buffer->ops;

return ops->store(kobj,attr,buffer->page,count);
@@ -238,8 +234,10 @@ sysfs_write_file(struct file *file, cons

static int check_perm(struct inode * inode, struct file * file)
{
- struct kobject * kobj = kobject_get(file->f_dentry->d_parent->d_fsdata);
- struct attribute * attr = file->f_dentry->d_fsdata;
+ struct sysfs_dirent * sd_attr = file->f_dentry->d_fsdata;
+ struct attribute * attr = sd_attr->s_element;
+ struct sysfs_dirent * sd_kobj = file->f_dentry->d_parent->d_fsdata;
+ struct kobject * kobj = kobject_get(sd_kobj->s_element);
struct sysfs_buffer * buffer;
struct sysfs_ops * ops = NULL;
int error = 0;
@@ -320,8 +318,10 @@ static int sysfs_open_file(struct inode

static int sysfs_release(struct inode * inode, struct file * filp)
{
- struct kobject * kobj = filp->f_dentry->d_parent->d_fsdata;
- struct attribute * attr = filp->f_dentry->d_fsdata;
+ struct sysfs_dirent * sd_attr = filp->f_dentry->d_fsdata;
+ struct attribute * attr = sd_attr->s_element;
+ struct sysfs_dirent * sd_kobj = filp->f_dentry->d_parent->d_fsdata;
+ struct kobject * kobj = kobject_get(sd_kobj->s_element);
struct sysfs_buffer * buffer = filp->private_data;

if (kobj)
@@ -336,7 +336,7 @@ static int sysfs_release(struct inode *
return 0;
}

-static struct file_operations sysfs_file_operations = {
+struct file_operations sysfs_file_operations = {
.read = sysfs_read_file,
.write = sysfs_write_file,
.llseek = generic_file_llseek,
@@ -345,23 +345,18 @@ static struct file_operations sysfs_file
};

-int sysfs_add_file(struct dentry * dir, const struct attribute * attr)
+int sysfs_add_file(struct dentry * parent, int t, const struct attribute * attr)
{
- struct dentry * dentry;
- int error;
+ struct sysfs_dirent * sd;
+ struct sysfs_dirent * parent_sd = parent->d_fsdata;
+ int error = 0;

- down(&dir->d_inode->i_sem);
- dentry = sysfs_get_dentry(dir,attr->name);
- if (!IS_ERR(dentry)) {
- error = sysfs_create(dentry,
- (attr->mode & S_IALLUGO) | S_IFREG,
- init_file);
- if (!error)
- dentry->d_fsdata = (void *)attr;
- dput(dentry);
- } else
- error = PTR_ERR(dentry);
- up(&dir->d_inode->i_sem);
+ down(&parent->d_inode->i_sem);
+ sd = sysfs_new_dirent(parent_sd, (void *) attr, t);
+ if (!sd)
+ error = -ENOMEM;
+ up(&parent->d_inode->i_sem);
+
return error;
}

@@ -374,8 +369,8 @@ int sysfs_add_file(struct dentry * dir,

int sysfs_create_file(struct kobject * kobj, const struct attribute * attr)
{
- if (kobj && attr)
- return sysfs_add_file(kobj->dentry,attr);
+ if (kobj && kobj->dentry && attr)
+ return sysfs_add_file(kobj->dentry, SYSFS_KOBJ_ATTR, attr);
return -EINVAL;
}

diff -puN fs/sysfs/inode.c~sysfs-leaves-file fs/sysfs/inode.c
--- linux-2.6.0/fs/sysfs/inode.c~sysfs-leaves-file 2003-12-29 12:43:44.000000000 +0530
+++ linux-2.6.0-maneesh/fs/sysfs/inode.c 2003-12-29 12:43:44.000000000 +0530
@@ -11,6 +11,8 @@
#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 = {
@@ -61,7 +63,8 @@ int sysfs_create(struct dentry * dentry,
error = init(inode);
if (!error) {
d_instantiate(dentry, inode);
- dget(dentry); /* Extra count - pin the dentry in core */
+ if (!S_ISREG(inode->i_mode))
+ dget(dentry); /* pin non-leaf dentry in core */
} else
iput(inode);
Done:
@@ -96,14 +99,24 @@ void sysfs_hash_and_remove(struct dentry
pr_debug("sysfs: Removing %s (%d)\n", victim->d_name.name,
atomic_read(&victim->d_count));

- d_delete(victim);
- simple_unlink(dir->d_inode,victim);
+ if (S_ISREG(victim->d_inode->i_mode)) {
+ spin_lock(&dcache_lock);
+ spin_lock(&victim->d_lock);
+ __d_drop(victim);
+ spin_unlock(&dcache_lock);
+ spin_unlock(&victim->d_lock);
+ }
+ else {
+ d_delete(victim);
+ simple_unlink(dir->d_inode,victim);
+ }
}
/*
* Drop reference from sysfs_get_dentry() above.
*/
dput(victim);
}
+ sysfs_remove_attr_dirent(dir->d_fsdata, name);
up(&dir->d_inode->i_sem);