[Qemu-devel] [Patch for-2.5 v2 5/6] qmp: add monitor command to add/remove a child

[Wen Congyang]

Signed-off-by: Wen Congyang <address@hidden>
Signed-off-by: zhanghailiang <address@hidden>
Signed-off-by: Gonglei <address@hidden>
---
 blockdev.c           | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 qapi/block-core.json | 40 ++++++++++++++++++++++++++
 qmp-commands.hx      | 67 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 186 insertions(+)

diff --git a/blockdev.c b/blockdev.c
index 62a4586..df40e92 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2186,6 +2186,23 @@ void hmp_drive_del(Monitor *mon, const QDict *qdict)
     aio_context_release(aio_context);
 }
 
+static void do_child_add(const char *device, QDict *opts, Error **errp)
+{
+    BlockDriverState *bs;
+    Error *local_err = NULL;
+
+    bs = bdrv_lookup_bs(device, device, &local_err);
+    if (!bs) {
+        error_propagate(errp, local_err);
+        return;
+    }
+
+    bdrv_add_child(bs, opts, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+    }
+}
+
 void qmp_block_resize(bool has_device, const char *device,
                       bool has_node_name, const char *node_name,
                       int64_t size, Error **errp)
@@ -3096,6 +3113,68 @@ fail:
     qmp_output_visitor_cleanup(ov);
 }
 
+void qmp_child_add(const char *device, BlockdevOptionsChild *options,
+                   Error **errp)
+{
+    QmpOutputVisitor *ov = qmp_output_visitor_new();
+    QObject *obj;
+    QDict *qdict;
+    Error *local_err = NULL;
+
+    if (options->child->has_id || options->child->has_discard ||
+        options->child->has_cache || options->child->has_aio ||
+        options->child->has_rerror || options->child->has_werror ||
+        options->child->has_read_only || options->child->has_detect_zeroes) {
+        error_setg(errp, "id, discard, cache, aio, rerror, werror, readonly"
+                   " and detect_zeroes cann't be used for child-add");
+        goto fail;
+    }
+
+    visit_type_BlockdevOptionsChild(qmp_output_get_visitor(ov),
+                                    &options, NULL, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        goto fail;
+    }
+
+    obj = qmp_output_get_qobject(ov);
+    qdict = qobject_to_qdict(obj);
+
+    qdict_flatten(qdict);
+
+    do_child_add(device, qdict, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        goto fail;
+    }
+
+fail:
+    qmp_output_visitor_cleanup(ov);
+}
+
+void qmp_child_del(const char *parent, const char *child, Error **errp)
+{
+    BlockDriverState *parent_bs, *child_bs;
+    Error *local_err = NULL;
+
+    parent_bs = bdrv_lookup_bs(parent, parent, &local_err);
+    if (!parent_bs) {
+        error_propagate(errp, local_err);
+        return;
+    }
+
+    child_bs = bdrv_lookup_bs(child, child, &local_err);
+    if (!child_bs) {
+        error_propagate(errp, local_err);
+        return;
+    }
+
+    bdrv_del_child(parent_bs, child_bs, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+    }
+}
+
 BlockJobInfoList *qmp_query_block_jobs(Error **errp)
 {
     BlockJobInfoList *head = NULL, **p_next = &head;
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 3ed8114..50292b9 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2122,3 +2122,43 @@
 ##
 { 'command': 'block-set-write-threshold',
   'data': { 'node-name': 'str', 'write-threshold': 'uint64' } }
+
+##
+# @BlockdevOptionsChild
+#
+# Driver specific block device options for child block device.
+#
+# Since: 2.5
+##
+{ 'struct': 'BlockdevOptionsChild',
+  'data': { 'child': 'BlockdevOptions' } }
+
+##
+# @child-add
+#
+# Add a new child to the parent BDS. Currently only the Quorum driver
+# implements this feature. This is useful to fix a broken quorum child.
+#
+# @device: graph node name or id which the child will be added to.
+#
+# @options: the options to create child BDS.
+#
+# Since: 2.5
+##
+{ 'command': 'child-add',
+  'data' : { 'device': 'str', 'options': 'BlockdevOptionsChild' } }
+
+##
+# @child-del
+#
+# Remove a child from the parent BDS. Currently only the Quorum driver
+# implements this feature. This is useful to fix a broken quorum child.
+#
+# @parent: graph node name or id from which the child will removed.
+#
+# @child: graph node name that will be removed.
+#
+# Since: 2.5
+##
+{ 'command': 'child-del',
+  'data' : { 'parent': 'str', 'child': 'str' } }
diff --git a/qmp-commands.hx b/qmp-commands.hx
index ba630b1..79a1146 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -3872,6 +3872,73 @@ Example (2):
 EQMP
 
     {
+        .name       = "child-add",
+        .args_type  = "device:B,options:q",
+        .mhandler.cmd_new = qmp_marshal_input_child_add,
+    },
+
+SQMP
+child-add
+------------
+
+Add a child to a quorum node.
+
+This command is still a work in progress. It doesn't support all
+block drivers. Stay away from it unless you want it to help with
+its development.
+
+Arguments:
+
+- "device": the quorum's id or node name
+- "options": the new child options
+
+Example:
+
+-> { "execute": "child-add",
+    "arguments": {
+        "device": "disk1",
+        "options" : {
+            "child": {
+                "driver": "qcow2",
+                "file": {
+                    "driver": "file",
+                    "filename": "test.qcow2"
+                },
+                "node-name": "new_node"
+            }
+        }
+    }
+<- { "return": {} }
+
+EQMP
+
+    {
+        .name        = "child-del",
+        .args_type   = "parent:B,child:B",
+        .mhandler.cmd_new = qmp_marshal_input_child_del,
+    },
+
+SQMP
+child-del
+------------
+
+Delete a child from a quorum node. It can be used to remove a broken
+quorum child.
+
+Arguments:
+
+- "parent": the quorum's id or node name
+- "child": the child node-name which will be removed
+
+Example:
+
+-> { "execute": "child-del",
+    "arguments": { "parent": "disk1", "child": "new_node" } }
+<- { "return": {} }
+
+EQMP
+
+    {
         .name       = "query-named-block-nodes",
         .args_type  = "",
         .mhandler.cmd_new = qmp_marshal_input_query_named_block_nodes,
-- 
2.4.3