Given a physical device with sectors 0, 1, 2, ..., LUKS will reserve some sectors at the beginning for the header. Other than this offset, can we assume the remaining sectors are mapped in order (offset+1 => 1, offset+2 => 2, etc.)? Is this documented anywhere?
Knowing this is crucial when resizing a LUKS partition. If sectors are mapped in order, then we can simply
cryptsetup resize --size <sectors> if we know how much space is actually used in the mapped device. Otherwise, we may lose data when doing so.