Re: [Qemu-devel] rbd: Possible regression in 2.9 RCs

[Eric Blake]

On 03/30/2017 06:42 PM, Alexandru Avadanii wrote:
> Hi,
> While testing out 2.9.0-rc2 on AArch64, we noticed a possible regression in 
> QEMU, related to parsing -drive 'file=rbd/...':
>> "conf option 6789 has no value".
> 
> Instance logs [1].

Pastebins don't last forever; it helps to paste the actual error message
in the email for archival purposes, and to make it easier for readers to
see your problem without having to chase URLs:

2017-03-30T20:02:27.499695Z qemu-system-aarch64: -drive
file=rbd:volumes/volume-ea141b5c-cdb3-4765-910d-e7008b209a70:id=compute:key=AQAVkvxXAAAAABAA9ZxWFYdRmV+DSwKr7BKKXg==:auth_supported=cephx\;none:mon_host=192.168.1.2\:6789,format=raw,if=none,id=drive-virtio-disk0,serial=ea141b5c-cdb3-4765-910d-e7008b209a70,cache=writeback:
conf option 6789 has no value

Looking at that, the only instance of 6789 that I see is the
'mon_host=192.168.1.2\:6789,' portion.  I bet what is happening is that
we are mis-parsing the string, and trying to treat it as a key-values
pair.  In other words, it's probably an unintended regression introduced
in the range of 7830f909..0a55679b by Jeff [3] or in Markus' cleanups
between f51c363c..2836284d [4].

On the bright side, we still have time to fix it before 2.9 goes final,
now that you called it to our attention.

> Occasionally, we get "conf option too long", with the same effect.
> 
> We bisected this manually between 2.8.0 (working ok with the above cmd) and 
> 2.9.0-rc2, and the problematic change seems to be the merge point [2].

I suspect you didn't run the bisect quite correctly, as that merge point
has nothing to do with block/rbd.c.

> 
> [1] http://paste.openstack.org/show/604938/
> [2] https://github.com/qemu/qemu/commit/9a81b79
> 

[3] https://lists.gnu.org/archive/html/qemu-devel/2017-02/msg07506.html
[4] https://lists.gnu.org/archive/html/qemu-devel/2017-03/msg05565.html

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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