Re: [Qemu-devel] [PATCH 4/6] qemu-ga: guest-suspend-disk: don't emit a success response

[Michael Roth <mdroth@linux.vnet.ibm.com>]

On Fri, May 04, 2012 at 05:20:20PM -0300, Luiz Capitulino wrote:
> Today, qemu-ga may not be able to emit a success response when
> guest-suspend-disk completes. This happens because the VM may
> vanish before qemu-ga is able to emit a response.
> 
> This semantic is a bit confusing, as it's not clear for clients if
> they should wait for a response or how they should check for success.
> 
> This commit solves that problem by changing guest-suspend-disk to
> never emit a success response and suggests in the documentation
> what clients could do to check for success.
> 
> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
> ---
>  qapi-schema-guest.json |   14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/qapi-schema-guest.json b/qapi-schema-guest.json
> index 0aa9f91..8ea7805 100644
> --- a/qapi-schema-guest.json
> +++ b/qapi-schema-guest.json
> @@ -361,17 +361,19 @@
>  # For the best results it's strongly recommended to have the pm-utils
>  # package installed in the guest.
>  #
> -# Returns: nothing on success
> +# Returns: This command does NOT return a response on success. There's a
> +# high chance the command succeeded if the VM exits with a zero exit status,
> +# but the VM could also exit due to other reasons.

Similar suggestion as previous patch (adding a note about query-status)

> +#
> +# The following errors may be returned:
>  #          If suspend to disk is not supported, Unsupported
>  #
> -# Notes: o This is an asynchronous request. There's no guarantee a response
> -#          will be sent
> -#        o It's strongly recommended to issue the guest-sync command before
> -#          sending commands when the guest resumes
> +# Notes: It's strongly recommended to issue the guest-sync command before
> +#        sending commands when the guest resumes
>  #
>  # Since: 1.1
>  ##
> -{ 'command': 'guest-suspend-disk' }
> +{ 'command': 'guest-suspend-disk', 'success-response': 'no' }
> 
>  ##
>  # @guest-suspend-ram
> -- 
> 1.7.9.2.384.g4a92a
>