Re: Re: [PATCH v4] qemu: add runtime config option for nbdkit
On Fri, Jan 05, 2024 at 01:30:19 -0800, Andrea Bolognani wrote:
On Fri, Jan 05, 2024 at 09:43:52AM +0100, Peter Krempa wrote:
> On Thu, Jan 04, 2024 at 23:39:38 +0100, Peter Krempa wrote:
> > On Thu, Jan 04, 2024 at 12:24:38 -0600, Jonathon Jongsma wrote:
> > > Currently when we build with nbdkit support, libvirt will always try to
> > > use nbdkit to access remote disk sources when it is available. But
> > > without an up-to-date selinux policy allowing this, it will fail.
> > > because the required selinux policies are not yet widely available, we
> > > have disabled nbdkit support on rpm builds for all distributions before
> > > Fedora 40.
> > >
> > > Unfortunately, this makes it more difficult to test nbdkit support.
> > > After someone updates to the necessary selinux policies, they would also
> > > need to rebuild libvirt to enable nbdkit support. By introducing a
> > > configure option (nbdkit_config_default), we can build packages with
> > > nbdkit support but have it disabled by default.
> > >
> > > Signed-off-by: Jonathon Jongsma <jjongsma(a)redhat.com>
> > > Suggested-by: Andrea Bolognani <abologna(a)redhat.com>
> > > ---
> > > changes in v4
> > > - squashed in Andrea's suggested changes
> > > - updated error message
> > > - Changed one instance of WITH_NDBKIT to WITH_NBDKIT :)
> > > - tested
> >
> > Looks like this broke the upstream CI on centos-stream-8 and mingw-fedoras:
> >
> > https://gitlab.com/libvirt/libvirt/-/jobs/5864171071
> >
> > Run-time dependency libnbd found: YES 1.6.0
> > meson.build:998:4: ERROR: Problem encountered: nbdkit support requires
pidfd_open(2)
> > A full log can be found at
/root/rpmbuild/BUILD/libvirt-10.0.0/x86_64-redhat-linux-gnu/meson-logs/meson-log.txt
> > error: Bad exit status from /var/tmp/rpm-tmp.HkQf7H (%build)
> > Bad exit status from /var/tmp/rpm-tmp.HkQf7H (%build)
>
> Okay there are two issues:
>
> - rhel-8 lacks pidfd_open() thus nbdkit support won't work there, and
> thus can't be force-enabled
>
> - mingw builds explicitly disable mingw, thus setting the new config
> option breaks as meson doesn't allow it if it's not used
>
> Patch will be posted soon after CI build succeeds.
I'll wait for your patch instead of investigating myself then :)
So, I've concluded the following:
- rhel-8 build needs to be disabled, it was enabled explicitly by this
patch, but the features are not there
- mingw builds for some unkonwn-to-me reason use
'--auto-features=enabled' which is weird
- the logic handling errors in use of the 'nbdkit_config_default' meson
option is a bit questionable:
--auto-features=enabled -Dnbdkit=disabled -Dnbdkit_config_default=auto
should NOT result in a failure even when the basic logic says so
My patch is strictly fixing the build failure by explicitly disabling
nbdkit_config_default on mingw and enabling 'nbdkit' only on rhel>=9.
You can investigate how to improve the questionable logic in
auto-selection of nbdkit_config_default.