https://unix.stackexchange.com/questions/509375/what-is-interrupted-system-call

    1.         loop {
    2.             let ret = uio::pwrite(self.fd, buf, offset as i64).map_err(|_| last_error!());
    4.             match ret {
    5.                 Ok(nr_write) => {
    6.                     trace!("write {}(offset={}) bytes to cache file", nr_write, offset);
    7.                     break;
    8.                 }
    9.                 Err(err) => {
    10.                     // Retry if the IO is interrupted by signal.
    11.                     if err.kind() != ErrorKind::Interrupted {
    12.                         return Err(err);
    13.                     }
    14.                 }
    15.             }
    16.         }

    当read write返回interrupted异常后，应该重试