Re: [PATCH RFC] qapi: Allow getting flat output from 'query-named-block-nodes'

[Eric Blake]

On 12/13/19 8:11 AM, Peter Krempa wrote:
> When a management application manages node names there's no reason to
> recurse into backing images in the output of query-named-block-nodes.
>
> Add a parameter to the command which will return just the top level
> structs.

At one point, Kevin was working on a saner command that tried to cut out 
on more than just the redundant nesting.  But this is certainly a 
quick-and-easy fix to ease libvirt's use of the existing command, while 
we decide whether to add a saner new command.

> Signed-off-by: Peter Krempa <address@hidden>
> ---
>   block.c               |  5 +++--
>   block/qapi.c          | 10 ++++++++--
>   blockdev.c            | 12 ++++++++++--
>   include/block/block.h |  2 +-
>   include/block/qapi.h  |  4 +++-
>   monitor/hmp-cmds.c    |  2 +-
>   qapi/block-core.json  |  6 +++++-
>   7 files changed, 31 insertions(+), 10 deletions(-)

> +++ b/blockdev.c
> @@ -3707,9 +3707,17 @@ void qmp_drive_backup(DriveBackup *arg, Error **errp)
>       }
>   }
>
> -BlockDeviceInfoList *qmp_query_named_block_nodes(Error **errp)
> +BlockDeviceInfoList *qmp_query_named_block_nodes(bool has_flat,
> +                                                 bool flat,
> +                                                 Error **errp)
>   {
> -    return bdrv_named_nodes_list(errp);
> +    bool return_flat = false;
> +
> +    if (has_flat) {
> +        return_flat = flat;
> +    }

This could be shortened as 'bool return_flat = has_flat && flat;', but 
that's not essential.

> +
> +    return bdrv_named_nodes_list(return_flat, errp);
>   }

Reviewed-by: Eric Blake <address@hidden>

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org