qmp: add monitor command to add/remove a child

The new QMP command name is x-blockdev-change. It's just for adding/removing
quorum's child now, and doesn't support all kinds of children, all kinds of
operations, nor all block drivers. So it is experimental now.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Signed-off-by: Changlong Xie <xiecl.fnst@cn.fujitsu.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 1462865799-19402-4-git-send-email-xiecl.fnst@cn.fujitsu.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
Wen Congyang 2016-05-10 15:36:39 +08:00 committed by Max Reitz
parent 98292c61bc
commit 7f82159769
3 changed files with 140 additions and 0 deletions

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@ -4092,6 +4092,61 @@ out:
aio_context_release(aio_context); aio_context_release(aio_context);
} }
static BdrvChild *bdrv_find_child(BlockDriverState *parent_bs,
const char *child_name)
{
BdrvChild *child;
QLIST_FOREACH(child, &parent_bs->children, next) {
if (strcmp(child->name, child_name) == 0) {
return child;
}
}
return NULL;
}
void qmp_x_blockdev_change(const char *parent, bool has_child,
const char *child, bool has_node,
const char *node, Error **errp)
{
BlockDriverState *parent_bs, *new_bs = NULL;
BdrvChild *p_child;
parent_bs = bdrv_lookup_bs(parent, parent, errp);
if (!parent_bs) {
return;
}
if (has_child == has_node) {
if (has_child) {
error_setg(errp, "The parameters child and node are in conflict");
} else {
error_setg(errp, "Either child or node must be specified");
}
return;
}
if (has_child) {
p_child = bdrv_find_child(parent_bs, child);
if (!p_child) {
error_setg(errp, "Node '%s' does not have child '%s'",
parent, child);
return;
}
bdrv_del_child(parent_bs, p_child, errp);
}
if (has_node) {
new_bs = bdrv_find_node(node);
if (!new_bs) {
error_setg(errp, "Node '%s' not found", node);
return;
}
bdrv_add_child(parent_bs, new_bs, errp);
}
}
BlockJobInfoList *qmp_query_block_jobs(Error **errp) BlockJobInfoList *qmp_query_block_jobs(Error **errp)
{ {
BlockJobInfoList *head = NULL, **p_next = &head; BlockJobInfoList *head = NULL, **p_next = &head;

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@ -2556,3 +2556,35 @@
## ##
{ 'command': 'block-set-write-threshold', { 'command': 'block-set-write-threshold',
'data': { 'node-name': 'str', 'write-threshold': 'uint64' } } 'data': { 'node-name': 'str', 'write-threshold': 'uint64' } }
##
# @x-blockdev-change
#
# Dynamically reconfigure the block driver state graph. It can be used
# to add, remove, insert or replace a graph node. Currently only the
# Quorum driver implements this feature to add or remove its child. This
# is useful to fix a broken quorum child.
#
# If @node is specified, it will be inserted under @parent. @child
# may not be specified in this case. If both @parent and @child are
# specified but @node is not, @child will be detached from @parent.
#
# @parent: the id or name of the parent node.
#
# @child: #optional the name of a child under the given parent node.
#
# @node: #optional the name of the node that will be added.
#
# Note: this command is experimental, and its API is not stable. It
# does not support all kinds of operations, all kinds of children, nor
# all block drivers.
#
# Warning: The data in a new quorum child MUST be consistent with that of
# the rest of the array.
#
# Since: 2.7
##
{ 'command': 'x-blockdev-change',
'data' : { 'parent': 'str',
'*child': 'str',
'*node': 'str' } }

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@ -4395,6 +4395,59 @@ Example:
<- { "return": {} } <- { "return": {} }
EQMP
{
.name = "x-blockdev-change",
.args_type = "parent:B,child:B?,node:B?",
.mhandler.cmd_new = qmp_marshal_x_blockdev_change,
},
SQMP
x-blockdev-change
-----------------
Dynamically reconfigure the block driver state graph. It can be used
to add, remove, insert or replace a graph node. Currently only the
Quorum driver implements this feature to add or remove its child. This
is useful to fix a broken quorum child.
If @node is specified, it will be inserted under @parent. @child
may not be specified in this case. If both @parent and @child are
specified but @node is not, @child will be detached from @parent.
Arguments:
- "parent": the id or name of the parent node (json-string)
- "child": the name of a child under the given parent node (json-string, optional)
- "node": the name of the node that will be added (json-string, optional)
Note: this command is experimental, and not a stable API. It doesn't
support all kinds of operations, all kinds of children, nor all block
drivers.
Warning: The data in a new quorum child MUST be consistent with that of
the rest of the array.
Example:
Add a new node to a quorum
-> { "execute": "blockdev-add",
"arguments": { "options": { "driver": "raw",
"node-name": "new_node",
"file": { "driver": "file",
"filename": "test.raw" } } } }
<- { "return": {} }
-> { "execute": "x-blockdev-change",
"arguments": { "parent": "disk1",
"node": "new_node" } }
<- { "return": {} }
Delete a quorum's node
-> { "execute": "x-blockdev-change",
"arguments": { "parent": "disk1",
"child": "children.1" } }
<- { "return": {} }
EQMP EQMP
{ {