Function async_read

block/src/qcow_sync.rs:352–366

(disk: &QcowDisk, offset: u64, len: usize)

    }

    fn async_read(disk: &QcowDisk, offset: u64, len: usize) -> Vec<u8> {
        let mut async_io = disk.create_async_io(1).unwrap();
        let mut buf = vec![0xFFu8; len];
        let iovec = libc::iovec {
            iov_base: buf.as_mut_ptr().cast(),
            iov_len: buf.len(),
        };
        async_io
            .read_vectored(offset as libc::off_t, &[iovec], 1)
            .unwrap();
        let (user_data, result) = async_io.next_completed_request().unwrap();
        assert_eq!(user_data, 1);
        assert_eq!(result as usize, len, "read should return requested length");
        buf
    }

    fn async_write(disk: &QcowDisk, offset: u64, data: &[u8]) {
        let mut async_io = disk.create_async_io(1).unwrap();