Re: [Qemu-devel] [Xen-devel] [PATCH] migration, xen: Fix block image lock issue on live migration

[Roger Pau Monné]

On Mon, Oct 02, 2017 at 04:30:58PM +0000, Anthony PERARD wrote:
> When doing a live migration of a Xen guest with libxl, the images for
> block devices are locked by the original QEMU process, and this prevent
> the QEMU at the destination to take the lock and the migration fail.
> 
> From QEMU point of view, once the RAM of a domain is migrated, there is
> two QMP commands, "stop" then "xen-save-devices-state", at which point a
> new QEMU is spawned at the destination.
> 
> Release locks in "xen-save-devices-state" so the destination can takes
> them.

What happens if the migration fails on the destination? Will QEMU pick
the lock again when resuming on the source in this case?

Thanks, Roger.