“The CDDL cannot apply to the Linux kernel because zfs.ko is a self-contained file system module — the kernel itself is quite obviously not a derivative work of this new file system.”
See Canonical accused of violating GPL with ZFS-in-Ubuntu 16.04 plan • The RegisterOnce again lawyers are getting things wrong and Canonical is following them down the wrong rabbit hole. A Linux kernel module is a derivative work of the Linux kernel, not the other way around. When compiling a kernel module, one needs the Linux kernel headers which are a part of the Linux kernel and which are licensed GPL v2. So, distributing Ubuntu GNU/Linux 16.04 violates the GPL v2 licence of the kernel and Canonical is asking for legal trouble. Since ZFS is most likely of interest to users of servers where Ubuntu has some traction it will be interesting to see whether or not this legal cloud slows adoption of 16.04 amongst the many businesses and organization that use Ubuntu on servers.
It looks to me that Canonical is claiming they don’t have to worry about violating CDDL and they don’t care that GPLv2 is violated. This is another example where they downplay the role of Linux in their system. This will not be good except it may get them some coverage in the news. Perhaps they consider legal suits as free advertising. We shall see.