Re: [Qemu-devel] [PATCH V4 1/4] Implement sync modes for drive-backup.

[Ian Main]

On Thu, Jul 18, 2013 at 11:19:43AM -0600, Eric Blake wrote:
> On 07/17/2013 02:04 PM, Ian Main wrote:
> > This patch adds sync-modes to the drive-backup interface and
> > implements the FULL, NONE and TOP modes of synchronization.
> > 
> > FULL performs as before copying the entire contents of the drive
> > while preserving the point-in-time using CoW.
> > NONE only copies new writes to the target drive.
> > TOP copies changes to the topmost drive image and preserves the
> > point-in-time using CoW.
> > 
> 
> > +++ b/qapi-schema.json
> > @@ -1807,6 +1807,10 @@
> >  # @format: #optional the format of the new destination, default is to
> >  #          probe if @mode is 'existing', else the format of the source
> >  #
> > +# @sync: what parts of the disk image should be copied to the destination
> > +#        (all the disk, only the sectors allocated in the topmost image, or
> > +#        only new I/O).
> > +#
> >  # @mode: #optional whether and how QEMU should create a new image, default 
> > is
> >  #        'absolute-paths'.
> 
> This hunk looks bogus; the 'DriveBackup' type already documents @sync as
> of commit b53169e, which makes me suspect this hunk got misapplied
> during rebasing.

Did you check that?  I know there was one bit of documentation missing
that I fixed here.  I also just did a clean rebase (git am) to
kevin/block and it all applied fine.
 
> >  #
> > diff --git a/qmp-commands.hx b/qmp-commands.hx
> > index e075df4..f3f6b3d 100644
> > --- a/qmp-commands.hx
> > +++ b/qmp-commands.hx
> > @@ -957,6 +957,7 @@ Arguments:
> >  
> >  Example:
> >  -> { "execute": "drive-backup", "arguments": { "device": "drive0",
> > +                                               "sync": "full",
> >                                                 "target": "backup.img" } }
> 
> Ouch - commit b53169e made 'sync' mandatory, but forgot to update the
> example to match; perhaps this hunk ought to be applied independently?

That's up to you guys, I can split it out if needed.

        Ian