As part of a continuing effort to broaden the potential uses of GlusterFS, the license for (most of) GlusterFS has been changed as follows (some details might vary between files).
/* Copyright (c) 2008-2012 Red Hat, Inc. <http://www.redhat.com> This file is part of GlusterFS. This file is licensed to you under your choice of the GNU Lesser General Public License, version 3 or any later version (LGPLv3 or later), or the GNU General Public License, version 2 (GPLv2), in all cases as published by the Free Software Foundation. */
Disclaimer: I am not a lawyer, nor am I representing Red Hat. These are my personal interpretations and predictions as a developer on an open-source project, regardless of qualifications or affiliation.
In practical terms, this means you can choose GPLv2 if you want to link with code already under that license (which FSF itself deems incompatible with GPLv3), or LGPLv3 if you want to link with just about anything else. There are some server-only parts that are still under only GPLv3+ to prevent others from combining our open source with their own closed source to sell a competing product against us, but even that’s still very much open source and always will be. This combination of licenses is a bit weird, but it has been carefully thought out to be consistent with both our ideals and commercial reality. In particular, it should enable users to combine our code with proprietary code for their own private use (which makes me sad but is part of that commercial reality) while also enabling developers to create new translators without having to worry about license conflicts or losing control of their own code. Because enabling translator development is a goal that I’ve spent hundreds of hours pursuing, this is a very welcome change. Yay!