Method check_data_bounds

block/src/request.rs:550–572

For In and Out requests, checks that the descriptors collectively fit in a backing disk of the given size. Returns `Ok(())` if they fit, or `ExecuteError::BadRequest` otherwise.

(&self, disk_nsectors: u64)

    /// For In and Out requests, checks that the descriptors collectively fit in a backing disk of
    /// the given size. Returns `Ok(())` if they fit, or `ExecuteError::BadRequest` otherwise.
    fn check_data_bounds(&self, disk_nsectors: u64) -> Result<(), ExecuteError> {
        if !matches!(self.request_type, RequestType::In | RequestType::Out) {
            return Ok(());
        }
        let mut total_bytes: u64 = 0;
        for (_, data_len) in &self.data_descriptors {
            total_bytes = total_bytes
                .checked_add(u64::from(*data_len))
                .ok_or(ExecuteError::BadRequest(Error::InvalidOffset))?;
        }
        if total_bytes == 0 {
            return Ok(());
        }
        let total_sectors = total_bytes.div_ceil(SECTOR_SIZE);
        let end_sector = self
            .sector
            .checked_add(total_sectors)
            .ok_or(ExecuteError::BadRequest(Error::InvalidOffset))?;
        if end_sector > disk_nsectors {
            return Err(ExecuteError::BadRequest(Error::InvalidOffset));
        }
        Ok(())
    }
}