Re: [Qemu-devel] [PATCH v5 0/3] Quorum maintaince operations

[Max Reitz]

On 30.05.2014 13:18, Benoît Canet wrote:
> These are the last bits required to make quorum usable in production.
>
> v5:     rebase on latest Stefan's block branch [Kevin]
>
> v4:
>          update patchset to stefan's block branch
>                  drop Max reviewed by because the series changes
>
> Benoît Canet (3):
>    quorum: Add the rewrite-corrupted parameter to quorum.
>    block: Add drive-mirror-replace command
>    qemu-iotests: Add 096 new test for drive-mirror-replace.

Independently of this series, while looking at patch 1 again (although I 
had reviewed it before already), I noticed that quorum_get_winner() does 
not select the definite winner, but only a winner. So if you have a 
quorum instance with four children and a threshold of two, it may happen 
that there are basically two winners which both fulfill the threshold 
condition. In this case, quorum_get_winner() will just return the first 
winner. However, I think it should then return that there is no winner 
(i.e., NULL).

On the other hand, the user should be aware that it may be a bad idea to 
choose a threshold which does not exceed half of the children count; 
thus, I'm just asking what you think about this. :-)

Max