int __check_sticky(struct inode *dir, struct inode *inode)
{
	kuid_t fsuid = current_fsuid();

	if (uid_eq(inode->i_uid, fsuid))
		return 0;
	if (uid_eq(dir->i_uid, fsuid))
		return 0;
	return !capable_wrt_inode_uidgid(inode, CAP_FOWNER);
}

Unknown