Function max_refcount_clusters

block/src/qcow/header.rs:586–597

(
    refcount_order: u32,
    cluster_size: u32,
    num_clusters: u32,
)

}

pub(super) fn max_refcount_clusters(
    refcount_order: u32,
    cluster_size: u32,
    num_clusters: u32,
) -> u64 {
    // Use u64 as the product of the u32 inputs can overflow.
    let refcount_bits = 0x01u64 << u64::from(refcount_order);
    let cluster_bits = u64::from(cluster_size) * 8;
    let for_data = div_round_up_u64(u64::from(num_clusters) * refcount_bits, cluster_bits);
    let for_refcounts = div_round_up_u64(for_data * refcount_bits, cluster_bits);
    for_data + for_refcounts
}

/// Returns an Error if the given offset doesn't align to a cluster boundary.
pub(super) fn offset_is_cluster_boundary(offset: u64, cluster_bits: u32) -> Result<()> {