Am 20.02.2015 um 14:53 hat Alberto Garcia geschrieben:
> This adds the 'top' parameter to the 'block-stream' QMP command and
> checks that its value is valid before passing it to stream_start().
>
> Signed-off-by: Alberto Garcia <be...@igalia.com>
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -1013,6 +1013,9 @@
> # with query-block-jobs. The operation can be stopped before it has
> completed
> # using the block-job-cancel command.
> #
> +# Data is copied to the top image, which defaults to the active layer if no
> other
> +# file is selected.
> +#
> # If a base file is specified then sectors are not copied from that base
> file and
> # its backing chain. When streaming completes the image file will have the
> base
> # file as its backing file. This can be used to stream a subset of the
> backing
> @@ -1025,8 +1028,14 @@
> #
> # @base: #optional the common backing file name
> #
> -# @backing-file: #optional The backing file string to write into the active
> -# layer. This filename is not validated.
> +# @top: #optional Top image, only sectors below this image are streamed
> +# into it.
> +#
> +# If not specified, the top image is the active layer.
> +# (Since 2.3)
> +#
> +# @backing-file: #optional The backing file string to write into the top
> +# image. This filename is not validated.
> #
> # If a pathname string is such that it cannot be
> # resolved by QEMU, that means that subsequent QMP
> or
> @@ -1052,8 +1061,9 @@
> # Since: 1.1
> ##
> { 'command': 'block-stream',
> - 'data': { 'device': 'str', '*base': 'str', '*backing-file': 'str',
> - '*speed': 'int', '*on-error': 'BlockdevOnError' } }
> + 'data': { 'device': 'str', '*base': 'str', '*top': 'str',
> + '*backing-file': 'str', '*speed': 'int',
> + '*on-error': 'BlockdevOnError' } }
While in patch 1 it would only be nice to avoid the additional argument,
I think we absolutely have to avoid it here in the external interface.
There is no point in specifying some root node as 'device' that isn't
actually involved in the operation; worse, it isn't even possible in the
general case because 'top' could have multiple users/parents.
A better interface would probably be to allow node names for 'device'
and leave everything else as it is.
Kevin
