[Cluster-devel] [PATCH] Move struct gfs2_rgrp_lvb out of gfs2_ondisk.h

[Andrew Price <anprice@redhat.com>]

On 15/01/2020 13:19, Bob Peterson wrote:
> ----- Original Message -----
>> Hi,
>>
>> On 15/01/2020 09:24, Andreas Gruenbacher wrote:
>>> On Wed, Jan 15, 2020 at 9:58 AM Steven Whitehouse <swhiteho@redhat.com>
>>> wrote:
>>>> On 15/01/2020 08:49, Andreas Gruenbacher wrote:
>>>>> There's no point in sharing the internal structure of lock value blocks
>>>>> with user space.
>>>> The reason that is in ondisk is that changing that structure is
>>>> something that needs to follow the same rules as changing the on disk
>>>> structures. So it is there as a reminder of that,
>>> I can see a point in that. The reason I've posted this is because Bob
>>> was complaining that changes to include/uapi/linux/gfs2_ondisk.h break
>>> his out-of-tree module build process. (One of the patches I'm working
>>> on adds an inode LVB.) The same would be true of on-disk format
>>> changes as well of course, and those definitely need to be shared with
>>> user space. I'm not usually building gfs2 out of tree, so I'm
>>> indifferent to this change.
>>>
>>> Thanks,
>>> Andreas
>>>
>> Why would we need to be able to build gfs2 (at least I assume it is
>> gfs2) out of tree anyway?
>>
>> Steve.
> 
> Simply for productivity. The difference is this procedure, which literally takes 10 seconds,
> if done simultaneously on all nodes using something like cssh:
> 
> make -C /usr/src/kernels/4.18.0-165.el8.x86_64 modules M=$PWD

I'd be concerned about this generating "chimera" modules that produce 
invalid test results.

> rmmod gfs2
> insmod gfs2.ko
> 
> Compared to a procedure like this, which takes at least 30 minutes:
> 
> make (a new kernel .src.rpm)
> scp or rsync the .src.rpm to a build machine
> cd ~/rpmbuild/
> rpm --force -i --nodeps /home/bob/*kernel-4.18.0*.src.rpm &> /dev/null
> echo $?
> rpmbuild --target=x86_64 -ba SPECS/kernel.spec
> ( -or- submit a "real" kernel build)
> then wait for the kernel build
> Pull down all necessary kernel rpms
> scp <those rpms> to all the nodes in the cluster
> rpm --force -i --nodeps <those rpms>
> /sbin/reboot all the nodes in the cluster
> wait for all the nodes to reboot, the cluster to stabilize, etc.

Isn't the next-best alternative just building the modules in-tree and 
copying them to the test machines? I'm not sure I understand the 
complication.

Perhaps we need cluster_install and cluster_modules_install rules in the 
build system :)

Andy