Method punch_hole

block/src/qcow_async.rs:202–238

(&mut self, offset: u64, length: u64, user_data: u64)

    }

    fn punch_hole(&mut self, offset: u64, length: u64, user_data: u64) -> AsyncIoResult<()> {
        let virtual_size = self.metadata.virtual_size();
        let cluster_size = self.cluster_size;

        let result = self
            .metadata
            .deallocate_bytes(
                offset,
                length as usize,
                self.sparse,
                virtual_size,
                cluster_size,
                self.backing_file.as_deref(),
            )
            .map_err(AsyncIoError::PunchHole);

        match result {
            Ok(actions) => {
                for action in &actions {
                    self.apply_dealloc_action(action);
                }
                self.completion_list.push_back((user_data, 0));
                self.eventfd.write(1).unwrap();
                Ok(())
            }
            Err(e) => {
                let errno = if let AsyncIoError::PunchHole(ref io_err) = e {
                    -io_err.raw_os_error().unwrap_or(libc::EIO)
                } else {
                    -libc::EIO
                };
                self.completion_list.push_back((user_data, errno));
                self.eventfd.write(1).unwrap();
                Ok(())
            }
        }
    }

    fn write_zeroes(&mut self, offset: u64, length: u64, user_data: u64) -> AsyncIoResult<()> {
        // For QCOW2, zeroing and hole punching are the same operation.