Re: [Qemu-devel] [PATCH v6 4/6] commit: support commit active layer

[Fam Zheng]

On 2013年12月14日 11:10, Eric Blake wrote:
> On 11/25/2013 10:45 PM, Fam Zheng wrote:
> > If active is top, it will be mirrored to base, (with block/mirror.c
> > code), then the image is switched when user completes the block job.
> >
> > QMP documentation is updated.
> >
> > Signed-off-by: Fam Zheng <address@hidden>
> > ---
>
> > +++ b/qapi-schema.json
> > @@ -1967,9 +1967,11 @@
> >   #
> >   # @top:              The file name of the backing image within the image 
> > chain,
> >   #                    which contains the topmost data to be committed down.
> > -#                    Note, the active layer as 'top' is currently unsupported.
> >   #
> >   #                    If top == base, that is an error.
> > +#                    If top == active, the job will not be completed by itself,
> > +#                    user needs to complete the job with the block-job-complete
> > +#                    command after getting the ready event. (Since 1.8)
>
> s/1.8/2.0/

OK, thanks.

Kevin, if you agree with my explanation on your comment, would you fix 
this while applying?

> What happens if the user does block-job-cancel instead of
> block-job-complete?  With drive-mirror, that leaves the mirrored drive
> as a nice copy at the point in time of the cancel.  I guess with commit,
> a cancel just aborts the commit and does not change which image is top.

True.