Re: [Qemu-devel] [Qemu-block] [PATCH v6 00/21] block: transactionless incremental backup series

[John Snow <jsnow@redhat.com>]

On 04/23/2015 03:18 PM, Eric Blake wrote:
> On 04/23/2015 08:41 AM, John Snow wrote:
>
>> I know I said "primarily to be difficult" but I was just being
>> facetious. I didn't find the GPL2+ to be suitable for documentation,
>> strictly, so I went to read up on the documentation licenses that the
>> fsf support/recommend.
>>
>> There's the GNU documentation license, but I found that unsuitable for a
>> couple reasons -- one of them was that you are forbidden(!) from
>> changing the text of the license,
>
> Note that it is usually only the license text proper that is locked
> down; the rest of the documentation is not under the same restriction
> unless you declare specific invariant sections such as a cover page. But
> I know that the Debian project has typically frowned upon any use of FDL
> with invariant sections, and the FDL has therefore earned a somewhat
> questionable reputation outside of FSF projects.
>

Understood; however the GNU FDL specifies within the license where and 
how the GNU FDL must be displayed. I didn't like these requirements, and 
might've used the FDL, but you are prohibited from altering the license, 
so I chose against this license.

It's too restrictive for me.

>> and there are some provisions in there
>> I didn't like, such as requiring the full text of the license to be
>> included with compiled copies of the document. That's not something I
>> care about -- a reference in source, for instance, is sufficient, or a
>> copy of the license being distributed *with* the compiled source is
>> fine, but I have no need for the full license to be copied with the
>> compiled version.
>
> Yes, I like those benefits of the FreeBSD Documentation License.
>
>>
>> The other documentation license the fsf recommends is the FreeBSD one,
>> and that one looked appealing, short, and to the point, so it is the one
>> I chose. It is essentially the FreeBSD license with words altered to
>> clarify what "code" and "source" means with respect to a document.
>
> In particular, according to the FSF, the FreeBSD Documentation License
> _should be_ acceptable for use with a GPLv2 program:
>
> https://www.gnu.org/philosophy/license-list.html#FreeDocumentationLicenses
>
> although this is probably not the right list to get a definitive answer
> from a lawyer familiar with the various copyright licenses and laws.
>
>>
>> Sorry for /actually/ being difficult; but Eric Blake was urging me to
>> select a license instead of relying on the implicit GPL, so I did go out
>> of my way to choose one I found appropriate.
>>
>> I stand by my pick.
>
> I also agree with the pick; I think that GPLv2+ on documentation is a
> bit questionable - if someone else implements the same interface using
> just the documentation, is their code required to be under the GPL by
> virtue of "using" the documentation?  Using a more permissive
> documentation license feels nicer to me, as it would allow non-GPL
> implementations if someone is so inclined.  Sorry if encouraging the
> issue has made matters more difficult.
>

It's too late! You've opened Pandora's Box!