Vladimir Sementsov-Ogievskiy <[email protected]> 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 <[email protected]>
[...]
> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index b82af74256..9cc7c3d140 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -6334,3 +6334,27 @@
> ##
> { 'struct': 'DummyBlockCoreForceArrays',
> 'data': { 'unused-block-graph-info': ['BlockGraphInfo'] } }
> +
> +##
> +# @blockdev-replace:
> +#
> +# Replace a block-node associated with device (@parent should be
> +# QOM path, and @child should be "root") or with block-export (@parent
> +# should be export name, and @child should be "root") or any child
> +# of block-node (@parent should be node-name, and @child should be any
> +# if its children names) with @new-child block-node.
of its
> +#
> +# @parent: QOM path or block-export or node-name, which @child should
> +# be repalced. If several matching parents exist, the command
replaced
> +# will fail
End the sentence with a period, please.
> +#
> +# @child: child to replace. Must be "root" when parent is QOM path or
> +# block-export
Likewise.
> +#
> +# @new-child: node-name of the block-node, which should become a
> +# replacement for @child's current block-node
Likewise.
Indent one more, please.
> +#
> +# Since 11.0
> +##
Let's see whether I understand...
@parent determines which of the three cases mentioned in the commit
message it ids:
* If @parent is a QOM path, case 1.
* If @parent is a block export name (@id in BlockExportOptions and
BlockExportInfo), case 2.
* If @parent is a block node name (@node-name in BlockdevOptions and
BlockDeviceInfo), case 3.
Correct?
Problem: this is ambiguous. A @parent "foo" could in fact be any of the
three cases.
3. If a block node named "foo" exists, it's case 3.
2. If a block export named "foo" exists, it's also case 2.
1. If exactly one QOM object named "foo" exists, it's also case 1. Why?
"foo" is a syntactically valid partial QOM path. Partial QOM paths
are a convenience feature that is virtually unknown (and possibly
ill-advised): you can omit leading path components as long as there's
no ambiguity.
Peeking ahead in the series... PATCH 8 appears to deprecate the
ambiguity between case 2. and 3.
I think we need to do better.
More questions...
In case 1 and 2, @child "should be root". What happens when it's
something else?
In case 3, @child "should be any if its children names". I figure the
command fails when it isn't.
> +{ 'command': 'blockdev-replace',
> + 'data': { 'parent': 'str', 'child': 'str', 'new-child': 'str' } }
[...]
