On February 18, Dustin Kirkland at Canonical wrote on his blog: "We at Canonical have conducted a legal review, including discussion with the industry's leading software freedom legal counsel, of the licenses that apply to the Linux kernel and to ZFS. And in doing so, we have concluded that we are acting within the rights granted and in compliance with their terms of both of those licenses...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. And zfs.ko, as a self-contained file system module, is clearly not a derivative work of the Linux kernel but rather quite obviously a derivative work of OpenZFS and OpenSolaris. Equivalent exceptions have existed for many years, for various other stand alone, self-contained, non-GPL kernel modules. Our conclusion is good for Ubuntu users, good for Linux, and good for all of free and open source software."
The SFS's blog post of today states: "We are sympathetic to Canonical's frustration in this desire to easily support more features for their users. However, as set out below, we have concluded that their distribution of zfs.ko violates the GPL."