Re: [PATCH 17/25] sysfs: Rewrite rename in terms of sysfs dirents

[Tejun Heo <htejun@gmail.com>]

>  int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
>  {
> -	struct sysfs_dirent *sd;
> +	struct sysfs_dirent *sd = kobj->sd;
>  	struct dentry *parent = NULL;
>  	struct dentry *old_dentry = NULL, *new_dentry = NULL;
>  	const char *dup_name = NULL;
> @@ -863,42 +863,41 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
>  
>  	mutex_lock(&sysfs_rename_mutex);
>  
> +	error = 0;
> +	if (strcmp(sd->s_name, new_name) == 0)
> +		goto out;	/* nothing to rename */
> +
>  	/* get the original dentry */
>  	old_dentry = sysfs_get_dentry(sd);
>  	if (IS_ERR(old_dentry)) {
>  		error = PTR_ERR(old_dentry);
> +		goto out;
>  	}
>  
>  	parent = old_dentry->d_parent;
>  
>  	/* lock parent and get dentry for new name */
>  	mutex_lock(&parent->d_inode->i_mutex);
> +	mutex_lock(&sysfs_mutex);
>  
> +	error = -EEXIST;
> +	if (sysfs_find_dirent(sd->s_parent, new_name))
>  		goto out_unlock;
>  
> +	error = -ENOMEM;
> +	new_dentry = d_alloc_name(parent, new_name);
> +	if (!new_dentry)
>  		goto out_unlock;
>  
>  	/* rename kobject and sysfs_dirent */
>  	error = -ENOMEM;
>  	new_name = dup_name = kstrdup(new_name, GFP_KERNEL);
>  	if (!new_name)
> +		goto out_unlock;
>  
>  	error = kobject_set_name(kobj, "%s", new_name);
>  	if (error)
> +		goto out_unlock;
>  
>  	mutex_lock(&sysfs_mutex);

sysfs_mutex is being grabbed twice and unlocked twice later.

-- 
tejun