rem: return EINVAL;
add: return FS_EINVAL;
context: sys_read_query(bool kernel, int fd, const char *path, void *cookie,struct dirent *dent,size_t bufferSize,long count){	int		err;	nspace	*ns;	fsystem	*fs;	vnode	*root;	long	num;    err = get_file_fd(TRUE, fd, path, TRUE, &root);    if (err)        return err;    ns = root->ns;    fs = ns->fs;    if (ns->root != root)        return EINVAL;	if (fs->ops.close_query == NULL) {		dec_vnode(root, FALSE);		return EPERM;	}	num = count;	err = (*fs->ops.read_query)(ns->data, cookie, &num, dent, bufferSize);	dec_vnode(root, FALSE);	if (err == 0)		return num;	return err;}