On 04.02.26 15:26, Markus Armbruster wrote:
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.
Yes. And we return an error in case of any ambiguity.
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?
Error returned. s/should/must/ ?
In case 3, @child "should be any if its children names". I figure the
command fails when it isn't.
And here.
+{ 'command': 'blockdev-replace',
+ 'data': { 'parent': 'str', 'child': 'str', 'new-child': 'str' } }
[...]
--
Best regards,
Vladimir
