[libvirt] [PATCH v3 REBASE 13/16] qemu: support getting disks stats during stopping block jobs

[Jiri Denemark]

On Thu, Aug 24, 2017 at 09:56:50 +0300, Nikolay Shirokovskiy wrote:
> Let's store disks stats for completed mirror jobs in current
> job info. So on getting migration job stats thru API
> we take records for completed jobs from current job info
> and records for still active jobs by querying qemu process.
> 
> As we need to keep disks stats for completed mirror jobs
> in current job let's zero out migration stats conditionally
> in fetching function.

This and the following hacks are not really needed. You can keep reading
block jobs stats until they become ready
(VIR_DOMAIN_DISK_MIRROR_STATE_READY) at which point the stats will
report the disk was completely transferred and they will not be updated
anymore. QEMU does not provide any statistics about data transferred
during the mirroring phase. Thus you can just fetch and store all block
job stats at the end of qemuMigrationDriveMirror when storage migration
phase is finished. Asking QEMU after this point doesn't make sense.

Jirka