Red Hat has countersued Twin Peaks Software, the California outfit that back in February and again in an amended complaint in July alleged that Gluster, Red Hat's bought-in storage subsidiary, infringes an August 2008 patent it holds on widgetry called a Mirror File System.

Despite all the patent litigation flying around, infringement charges against Red Hat are pretty darn rare.

Twin Peaks' claims touch GlusterFS technology such as the Red Hat Storage Software Appliance and Red Hat Virtual Storage Appliance.

Red Hat denies any infringement and claims the Twin Peaks patent (US No 7,418,439) is invalid because it has no utility. It says Twin Peaks isn't entitled to the injunction it wants.

Red Hat wants a declaratory judgment of non-infringement and invalidity from the district court in San Jose where Twin Peaks filed.

It also claims - we're getting to the interesting part here - that Twin Peaks' proprietary replication software treads on the freely available open source "mount" program in util-linux licensed under the GPL 2 to which Red Hat has made significant contributions over the years and that are covered by copyrights in its name.

What's more, Red Hat claims that Twin Peaks copied substantial portions of the open source code into its own "mount.mfs" tool, including source code Red Hat wrote for the so-called mount program released in util-linux version 2.12a.

It says "Twin Peaks' verbatim and near-verbatim copying of open source and Red Hat source code into its ‘mount.mfs' tool is pervasive and extensive." (Now it knows how SCO felt.)

It charges Twin Peaks with breaking the GPL by not releasing source code and "illegally free-riding off of Red Hat's contributions to util-linux, as well as the contributions of many others in the FOSS community to that software."

It wants damages and disgorgement of profits for willful infringement of its copyrights and the GPL, a permanent injunction and infringing materials impounded.

Failing a declaratory judgment, Red Hat says, like Twin Peaks before it, that it wants a jury trial and attorneys' fees.

Red Hat's copyright looks a tad shiny new: Copyright Reg. Nos. TX 7-557-456 (August 13, 2012), entitled "Mount - 2.10m" and TX-7-557-458 (August 13, 2012), entitled "Mount - 2.12a."