Re: [Qemu-block] [Qemu-devel] [PATCH] block/mirror: fix fail to cancel when VM has heavy BLK IO

[Eric Blake]

On 01/24/2018 10:59 PM, Liang Li wrote:
>>
>> There's ongoing work on adding async mirroring; this may be a better
>> solution to the issue you are seeing.
>>
>> https://lists.gnu.org/archive/html/qemu-devel/2018-01/msg05419.html
>>
> Hi Eric,
> 
> Thinks for your information, I didn't know libvirt depends on 
> 'block-job-cancel'
> for some of the block related operations.
> 
> It's seems a new interface should provided by qemu for use case that just
> for aborting block job and don't care abort the mirror data integrality, and
> libvirt can make use of this new interface.
> 
> Do you think this is the right direction?

I don't know if it is better to wait for the new async mirroring code to
land, or to just propose a new QMP command that can force-quit an
ongoing mirror in the READY state, but you are correct that the only
safe way to do it is by adding a new command (or a new optional flag to
the existing block-job-cancel command).

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

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