The Software Freedom Conservancy (SFC) thinks Canonical, the curator of Ubuntu, has breached the Gnu General Public Licence (GPL).

As the Conservancy explains, Canonical recently announced that Ubuntu 16.04 will “make OpenZFS available on every Ubuntu system. Canonical reckons that adding OpenZFS represents “one of the most exciting new features Linux has seen in a very long time.”

A couple of days after announcing that it would add OpenZFS to Ubuntu, Canonical's Dustin Kirkland returned to the subject in a post titled ZFS Licensing and Linux in which he explained that “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 SFC disagrees, because ZFS saw the light of day when Sun released OpenSolaris under the Common Development and Distribution License, version 1 (CDDLv1). The Conservancy says “unfortunately, CDDLv1 is incompatible with GPLv2, so distribution of binaries is not permitted.”

The SFC's Bradley M. Kuhn and Karen M. Sandler reach that conclusion because they believe adding OpenZFS to Linux means the former code comes under the GPLv2 that governs the latter, and the GPLv2 requires any derivatives to use the GPLv2 licence. With ZFS made available under CDDLv1, the Conservancy argues it's just not possible for GPLv2 to apply.

Canonical's counter-argument is that “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.”

For now this is a battle of the blogs. Canonical's made the two posts linked above and the Conservancy weighed in on February 25th. Both sides of the argument knew of the SFC post and the Conservancy says it hopes “to continue dialogue with Canonical regarding their violation.”

“We do not give up on friendly resolution of a GPL violation easily and are glad Canonical seeks to transparently discuss both sides of this issue in public.”

The root of the problem seems to be Sun, and its current owner Oracle, as both have stuck to the CDDLv1 licence. “Many community members have been frustrated for years that Oracle didn't simply relicense the code under a GPLv2-compatible license,” the SFC writes, calling on Big Red to pull its finger out and get it done.

Oracle famously fought a protracted lawsuit with NetApp over ZFS and who can employ it and when. Big Red's also claimed it's sold a billion dollars worth of ZFS appliances, so clearly has a business that might justify its ongoing use of the CDDLv1. ®