EFS_EXTENTS_PER_BB
numextents = ex.ex_length * EFS_EXTENTS_PER_BB;
bboff = mid / EFS_EXTENTS_PER_BB;
index = mid % EFS_EXTENTS_PER_BB;
bboff = exi->exi_innext / EFS_EXTENTS_PER_BB;
index = exi->exi_innext % EFS_EXTENTS_PER_BB;
bboff = exi->exi_innext++ / EFS_EXTENTS_PER_BB;