Re: [PATCH v8 4/7] qapi: add x-blockdev-replace command

[Markus Armbruster]

Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> writes:

> Add a command that can replace bs in following BdrvChild structures:
>
>  - qdev blk root child
>  - block-export blk root child
>  - any child of BlockDriverState selected by child-name
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
> ---

[...]

> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index 89751d81f2..cf92e0df8b 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -6054,3 +6054,86 @@
>  ##
>  { 'struct': 'DummyBlockCoreForceArrays',
>    'data': { 'unused-block-graph-info': ['BlockGraphInfo'] } }
> +
> +##
> +# @BlockParentType:
> +#
> +# @qdev: block device, such as created by device_add, and denoted by
> +#     qdev-id
> +#
> +# @driver: block driver node, such as created by blockdev-add, and
> +#     denoted by node-name
> +#
> +# @export: block export, such created by block-export-add, and
> +#     denoted by export-id
> +#
> +# Since 8.2
> +##
> +{ 'enum': 'BlockParentType',
> +  'data': ['qdev', 'driver', 'export'] }
> +
> +##
> +# @BdrvChildRefQdev:
> +#
> +# @qdev-id: the device's ID or QOM path
> +#
> +# Since 8.2
> +##
> +{ 'struct': 'BdrvChildRefQdev',
> +  'data': { 'qdev-id': 'str' } }
> +
> +##
> +# @BdrvChildRefExport:
> +#
> +# @export-id: block export identifier
> +#
> +# Since 8.2
> +##
> +{ 'struct': 'BdrvChildRefExport',
> +  'data': { 'export-id': 'str' } }
> +
> +##
> +# @BdrvChildRefDriver:
> +#
> +# @node-name: the node name of the parent block node
> +#
> +# @child: name of the child to be replaced, like "file" or "backing"
> +#
> +# Since 8.2
> +##
> +{ 'struct': 'BdrvChildRefDriver',
> +  'data': { 'node-name': 'str', 'child': 'str' } }
> +
> +##
> +# @BlockdevReplace:
> +#
> +# @parent-type: type of the parent, which child is to be replaced
> +#
> +# @new-child: new child for replacement
> +#
> +# Since 8.2
> +##
> +{ 'union': 'BlockdevReplace',
> +  'base': {
> +      'parent-type': 'BlockParentType',
> +      'new-child': 'str'
> +  },
> +  'discriminator': 'parent-type',
> +  'data': {
> +      'qdev': 'BdrvChildRefQdev',
> +      'export': 'BdrvChildRefExport',
> +      'driver': 'BdrvChildRefDriver'
> +  } }
> +
> +##
> +# @x-blockdev-replace:
> +#
> +# Replace a block-node associated with device (selected by
> +# @qdev-id) or with block-export (selected by @export-id) or
> +# any child of block-node (selected by @node-name and @child)
> +# with @new-child block-node.
> +#
> +# Since 8.2
> +##
> +{ 'command': 'x-blockdev-replace', 'boxed': true,
> +  'data': 'BlockdevReplace' }
> diff --git a/stubs/blk-by-qdev-id.c b/stubs/blk-by-qdev-id.c
> new file mode 100644
> index 0000000000..0e751ce4f7
> --- /dev/null
> +++ b/stubs/blk-by-qdev-id.c
> @@ -0,0 +1,9 @@
> +#include "qemu/osdep.h"
> +#include "qapi/error.h"
> +#include "sysemu/block-backend.h"
> +
> +BlockBackend *blk_by_qdev_id(const char *id, Error **errp)
> +{
> +    error_setg(errp, "blk '%s' not found", id);

Is this expected to happen?

> +    return NULL;
> +}

[...]

QAPI schema
Acked-by: Markus Armbruster <armbru@redhat.com>