Re: [PATCH V2 1/7] block/rbd: bump librbd requirement to luminous release

[Daniel P . Berrangé]

On Mon, Feb 15, 2021 at 12:55:24PM +0100, Peter Lieven wrote:
> Am 15.02.21 um 12:51 schrieb Daniel P. Berrangé:
> > On Mon, Feb 15, 2021 at 12:45:01PM +0100, Peter Lieven wrote:
> > > Am 15.02.21 um 12:41 schrieb Daniel P. Berrangé:
> > > > On Mon, Feb 15, 2021 at 12:32:24PM +0100, Peter Lieven wrote:
> > > > > Am 15.02.21 um 11:24 schrieb Daniel P. Berrangé:
> > > > > > On Tue, Jan 26, 2021 at 12:25:34PM +0100, Peter Lieven wrote:
> > > > > > > even luminous (version 12.2) is unmaintained for over 3 years now.
> > > > > > > Bump the requirement to get rid of the ifdef'ry in the code.
> > > > > > We have clear rules on when we bump minimum versions, determined by
> > > > > > the OS platforms we target:
> > > > > > 
> > > > > >      
> > > > > > https://qemu.readthedocs.io/en/latest/system/build-platforms.html
> > > > > > 
> > > > > > At this time RHEL-7 is usually the oldest platform, and it
> > > > > > builds with RBD 10.2.5, so we can't bump the version to 12.2.
> > > > > > 
> > > > > > I'm afraid this patch has to be dropped.
> > > > > I have asked exactly this question before I started work on this 
> > > > > series and got reply
> > > > > 
> > > > > from Jason that he sees no problem in bumping to a release which is 
> > > > > already unmaintained
> > > > > 
> > > > > for 3 years.
> > > > I'm afraid Jason is wrong here.  It doesn't matter what the upstream
> > > > consider the support status to be. QEMU targets what the OS vendors
> > > > ship, and they still consider this to be a supported version.
> > > 
> > > Okay, but the whole coroutine stuff would get a total mess with all the 
> > > ifdef'ry.
> > Doesn't seem like the write zeros code is adding much more comapred to
> > the ifdefs that already exist...
> 
> 
> Yes, I don't like it as well, but write zeroes support was only added in 
> Nautilus (14.x) and the thick provisioning
> 
> that Jason asked me to add came only with Octopus (15.x).
> 
> 
> > 
> > 
> > > Would it be an option to make a big ifdef in the rbd driver? One with old 
> > > code for < 12.0.0 and one
> > > 
> > > with new code for >= 12.0.0?
> > ..but I don't have a strong opinion on that, since I'm not maintaining this
> > driver.
> > 
> > 
> > BTW, we will be free to drop RHEL-7 in the next development cycle of
> > QEMU, starting after the forthcoming 6.0.0 release is out, as it will
> > fall out of our OS support matrix.
> 
> 
> Thanks for that hint. I would say lets hold this series back until Qemu 6.1.
> 
> Where can I find the OS support matrix for 6.1 - maybe we can bump the 
> requirement to nautilus to
> 
> reduce the ifdef'ry further.

The rules are documented here:

  https://qemu.readthedocs.io/en/latest/system/build-platforms.html

RHEL-7 falls out because in May it will be 2 years since RHEL-8 came
out and thus

  "The project aims to support the most recent major version at
   all times. Support for the previous major version will be 
   dropped 2 years after the new major version is released or 
   when the vendor itself drops support, whichever comes first."

someone has todo the investigation to find out versions across the
distros.

Regards,
Daniel
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