XFS_MAX_CONTIG_RTRMAPS_PER_BLOCK
XFS_MAX_CONTIG_RTRMAPS_PER_BLOCK(mp)) *
((((b) + XFS_MAX_CONTIG_RTRMAPS_PER_BLOCK(mp) - 1) / \
XFS_MAX_CONTIG_RTRMAPS_PER_BLOCK(mp)) * \