Re: [PATCH 10/13] sysfs: In sysfs_chmod_file lazily propagate the mode change.

Serge E. Hallyn
2009-11-04T04:23:44Z

Quoting Eric W. Biederman (ebiederm@xmission.com):
> From: Eric W. Biederman <ebiederm@xmission.com>
>
> Now that sysfs_getattr and sysfs_permission refresh the vfs
> inode there is no need to immediatly push the mode change
> into the vfs cache. Reducing the amount of work needed and
> simplifying the locking.
>
> Acked-by: Tejun Heo <tj@kernel.org>
> Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>

Nice.

Acked-by: Serge Hallyn <serue@us.ibm.com>

> ---
> fs/sysfs/file.c | 31 ++++++++-----------------------
> 1 files changed, 8 insertions(+), 23 deletions(-)
>
> diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
> index faa1a80..dc30d9e 100644
> --- a/fs/sysfs/file.c
> +++ b/fs/sysfs/file.c
> @@ -579,38 +579,23 @@ EXPORT_SYMBOL_GPL(sysfs_add_file_to_group);
> */
> int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode)
> {
> - struct sysfs_dirent *victim_sd = NULL;
> - struct dentry *victim = NULL;
> - struct inode * inode;
> + struct sysfs_dirent *sd;
> struct iattr newattrs;
> int rc;
>
> - rc = -ENOENT;
> - victim_sd = sysfs_get_dirent(kobj->sd, attr->name);
> - if (!victim_sd)
> - goto out;
> + mutex_lock(&sysfs_mutex);
>
> - mutex_lock(&sysfs_rename_mutex);
> - victim = sysfs_get_dentry(victim_sd);
> - mutex_unlock(&sysfs_rename_mutex);
> - if (IS_ERR(victim)) {
> - rc = PTR_ERR(victim);
> - victim = NULL;
> + rc = -ENOENT;
> + sd = sysfs_find_dirent(kobj->sd, attr->name);
> + if (!sd)
> goto out;
> - }
> -
> - inode = victim->d_inode;
>
> - mutex_lock(&inode->i_mutex);
> -
> - newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
> + newattrs.ia_mode = (mode & S_IALLUGO) | (sd->s_mode & ~S_IALLUGO);
> newattrs.ia_valid = ATTR_MODE;
> - rc = sysfs_setattr(victim, &newattrs);
> + rc = sysfs_sd_setattr(sd, &newattrs);
>
> - mutex_unlock(&inode->i_mutex);
> out:
> - dput(victim);
> - sysfs_put(victim_sd);
> + mutex_unlock(&sysfs_mutex);
> return rc;
> }
> EXPORT_SYMBOL_GPL(sysfs_chmod_file);
> --
> 1.6.5.2.143.g8cc62
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html