[p_l]

CDDL ensures OpenZFS can be used for not just Linux, and prevents patent-based attacks (which have been used against GPLv2 code reuse in the past).

So the OpenZFS team is not exactly interested in moving to GPLv2, because it would break multiple platforms.

[Sanzig]

I doubt the OpenZFS team would move to GPLv2 if they were able to relicense to anything they wanted. Given their close association with FreeBSD, BSD-2 or a similar permissive license wouldn't shock me.

But it's an academic exercise anyway, since it seems Oracle has no intention of allowing them to relicense.