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sysfs: In sysfs_chmod_file lazily propagate the mode change. 

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>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Eric W. Biederman 2009-11-20 16:08:54 -08:00 committed by Greg Kroah-Hartman
parent e61ab4ae48
commit 06fc0d66f7
1 changed files with 8 additions and 23 deletions
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31
fs/sysfs/file.c
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@ -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;
mutex_lock(&sysfs_mutex);
rc = -ENOENT;
victim_sd = sysfs_get_dirent(kobj->sd, attr->name);
if (!victim_sd)
sd = sysfs_find_dirent(kobj->sd, attr->name);
if (!sd)
goto out;
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;
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);