[libvirt] [PATCHv2 10/15] blockjob: support pivot operation on cancel

[Paolo Bonzini]

Il 06/04/2012 06:36, Eric Blake ha scritto:
> if
> 'block_job_cancel' were made part of 'transaction', you could
> copy multiple disks at the same point in time without pausing
> the domain.

This is doable.

The transactioned command would do a qemu_aio_flush() in the prepare
phase, and a normal block_job_cancel in the commit phase.

> This also implies we may want to add a --quiesce
> flag to the pivot operation, so that when breaking a mirror, the
> side of the mirror that we are abandoning is at least in a stable
> state with regards to guest I/O.

I don't think this is needed.  Either it makes a difference so it should
be the default, or it doesn't and then it is not a useful knob.

Paolo