Re: [Qemu-devel] [PATCH] block: add drive_backup HMP command

[Kevin Wolf <kwolf@redhat.com>]

Am 25.06.2013 um 14:23 hat Stefan Hajnoczi geschrieben:
> Make "drive_backup" available on the HMP monitor:
> 
>   drive_backup [-n] [-f] device target [format]
> 
> The -n flag requests QEMU to reuse the image found in new-image-file,
> instead of recreating it from scratch.
> 
> The -f flag requests QEMU to copy the whole disk, so that the result
> does not need a backing file.  Note that this flag *must* currently be
> passed since the other sync modes ('none' and 'top') have not been
> implemented yet.
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  hmp-commands.hx | 20 ++++++++++++++++++++
>  hmp.c           | 33 +++++++++++++++++++++++++++++++++
>  hmp.h           |  1 +
>  3 files changed, 54 insertions(+)

> --- a/hmp.c
> +++ b/hmp.c
> @@ -889,6 +889,39 @@ void hmp_drive_mirror(Monitor *mon, const QDict *qdict)
>      hmp_handle_error(mon, &errp);
>  }
>  
> +void hmp_drive_backup(Monitor *mon, const QDict *qdict)
> +{
> +    const char *device = qdict_get_str(qdict, "device");
> +    const char *filename = qdict_get_str(qdict, "target");
> +    const char *format = qdict_get_try_str(qdict, "format");
> +    int reuse = qdict_get_try_bool(qdict, "reuse", 0);
> +    int full = qdict_get_try_bool(qdict, "full", 0);
> +    enum NewImageMode mode;
> +    Error *errp = NULL;

> +
> +    if (!filename) {
> +        error_set(&errp, QERR_MISSING_PARAMETER, "target");
> +        hmp_handle_error(mon, &errp);
> +        return;
> +    }
> +
> +    if (reuse) {
> +        mode = NEW_IMAGE_MODE_EXISTING;
> +    } else {
> +        mode = NEW_IMAGE_MODE_ABSOLUTE_PATHS;
> +    }
> +
> +    if (!full) {
> +        error_setg(&errp, "-f is not yet implemented");
> +        hmp_handle_error(mon, &errp);
> +        return;
> +    }

Then why make it a valid option and confuse users in the help text by
describing options that don't really exist?

> +    qmp_drive_backup(device, filename, !!format, format,
> +                     true, mode, false, 0, false, 0, false, 0, &errp);
> +    hmp_handle_error(mon, &errp);
> +}

Kevin