file_put_contents(): Only 0 of 79 bytes written, possibly out of free disk space

        if ($this->tag && !is_file($filename)) {
            $first = true;
        }
        $data = serialize($value);
        if ($this->options['data_compress'] && function_exists('gzcompress')) {
            //数(Shu)据(Ju)压(Ya)缩(Suo)
            $data = gzcompress($data, 3);
        }
        $data   = "<?php\n//" . sprintf('%012d', $expire) . $data . "\n?>";
        $result = file_put_contents($filename, $data);
        if ($result) {
            isset($first) && $this->setTagItem($filename);
            clearstatcache();
            return true;
        } else {
            return false;
        }
    }