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

[Eric Blake <eblake@redhat.com>]

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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.

>  #
> 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?

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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