As this timeline and some Googling shows: https://en.wikipedia.org/wiki/OpenZFS#History Sun did work in good faith with Apple, and the Linux community to get them to adopt ZFS, unsuccessfully (successfully with FreeBSD). Additionally, the fact that Sun did successfully open source quite a few things (virtualbox, jenkins, openam, solaris, staroffice, netbeans, etc..) and relicense Java from SCSL to GPL, makes their intentions towards the open source community pretty clear. Yes, they wanted to make money, but they probably open sourced and created more open source communities than any other company in SV history.
Now, about modification, any open source license listed by the FSF will grant modification rights to users. I don't think compiling is making a derivative work. It's like unfolding a chair to sit on it. It's just a part of normal usage of software, you can decompile a binary and learn from it, also normal usage. The compiler is a tool, like a screw driver or paint gun that will let you assemble a chair or paint your car. Reading and learning from source code is usage too. Modifying the actual source code would be a real modification and could be making ZFS work on an Raspberry Pi, which is allowed by open source. Given that Sun wanted ZFS to be widely adopted in open source, they adopted the CDDL to let people modify ZFS so it could be used by OSes other than Solaris. This is what the OpenZFS community enables, and is completely compatible with GNU/Linux or Apache open source norms. Oracle might come knocking for money, but that's not the history of Sun or current ZFS contributors, who are just out to make better software using the open source process. They would probably not disagree with what Netgear or Canonical did, and if they did, it would be on the OpenZFS mailing list and in a news story or two. It's not.
You can't copy books and sell them, and I can understand you can't modify an original artwork and not affect the copyright owner's rights. You can correct an error in a book or claim inspiration from a painting to make another. You can't claim copyright if someone uses a binary in a VM when you didn't intend it. You can give others the right to modify source code, and ask that others do the same. That is open source and the GPL. OpenZFS, FreeBSD, have as much standing as Oracle, which is really none, to actually stop someone from porting ZFS to anything they would like and distribute it along side proprietary or open source software.
The other side is of course each one of the linux developers, each holding the full power of copyright. To cite SFLC, no free software developers have ever sued an other free software developer over license incompatibility, so its very unlikely to happen with ZFS. Such court cases really on happen between companies.
So to sum up, a case over ZFS is very unlikely, but I would not bet on what would happen if android suddenly started to use ZFS.
I wonder what Linux Torvalds thinks about merging ZFS into Linux now, he wasn't too keen a decade ago. Sun is no longer around, someone worse like Oracle has taken their place. A couple of lessons for the open source community here, I think. And Brian Cantrill nails in on the head in the youtube video link.
ZFS will need to be on Linux first before it can show up on Android or media centers or gaming consoles, and I don't doubt Oracle's ability to find a way to patent troll anything. But it will be just that: patent or copyright trolling.
[1] https://en.wikipedia.org/wiki/Common_Development_and_Distrib...
Canonical, Debian and SFLC have really done with right thing by distributing ZFS on Linux, using AFS as a precedence. I hope more merging like this can happen in open source in the future.
Intent by everyone involved such as the author, the accused and the law writer. If the author intended that the work is used in one way, and the accused knew this but decided to go against it, then that carries a lot of weight. Similar, if the law writer intended the law to address a specific situation, that also carries weight.
Precedence from cases that involve derivate work. There is a fuzzy line when two works merge to create a third. Music has a large legal history, parts which are contradicting itself.
And last there is the law itself. Modifying for example is a explicit exclusive right in some places (such as the US). One case involved a person who bought a painting, cut it down into squares, and rearranged them into a mosaic version. The painter sued and won the case, arguing exclusive right to create modifications. If something is binary or source code should irrelevant to the question about if the "work" has been modified based on what the author originally created.