Method fsync

block/src/raw_sync.rs:91–104

(&mut self, user_data: Option<u64>)

    }

    fn fsync(&mut self, user_data: Option<u64>) -> AsyncIoResult<()> {
        // SAFETY: FFI call
        let result = unsafe { libc::fsync(self.fd as libc::c_int) };
        if result < 0 {
            return Err(AsyncIoError::Fsync(std::io::Error::last_os_error()));
        }

        if let Some(user_data) = user_data {
            self.completion_list.push_back((user_data, result));
            self.eventfd.write(1).unwrap();
        }

        Ok(())
    }

    fn next_completed_request(&mut self) -> Option<(u64, i32)> {
        self.completion_list.pop_front()