Commit 7f821597 authored by Wen Congyang's avatar Wen Congyang Committed by Max Reitz
Browse files

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: default avatarWen Congyang <wency@cn.fujitsu.com>
Signed-off-by: default avatarzhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: default avatarGonglei <arei.gonglei@huawei.com>
Signed-off-by: default avatarChanglong Xie <xiecl.fnst@cn.fujitsu.com>
Reviewed-by: default avatarMax Reitz <mreitz@redhat.com>
Reviewed-by: default avatarAlberto Garcia <berto@igalia.com>
Message-id: 1462865799-19402-4-git-send-email-xiecl.fnst@cn.fujitsu.com
Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
parent 98292c61

blockdev.c

+55 −0
Original line number Diff line number Diff line
@@ -4092,6 +4092,61 @@ out: 
    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 *head = NULL, **p_next = &head;

qapi/block-core.json

+32 −0
Original line number Diff line number Diff line
@@ -2556,3 +2556,35 @@ 
##

{ 'command': 'block-set-write-threshold',

  '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' } }

qmp-commands.hx

+53 −0
Original line number Diff line number Diff line
@@ -4395,6 +4395,59 @@ Example: 


<- { "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



    {