Features/Block/Rebase

Summary

Add dynamic rebase of running disk

Owner

• Name: Choonho Son
• Email: choonho.son@gmail.com

Description

qapi-schema.json

##
# @block_rebase
#
# This command will change backing file of disk.
#
# Since: 2.x
##
{ 'command': 'block_rebase',
  'data' : { 'device' : 'str',
             'file' : 'str' } }

qmp-command.hx

    {
        .name       = "block_rebase",
        .args_type  = "device:s,file:s",
        .mhandler.cmd_new = qmp_marshal_input_block_rebase,
    },

SQMP
block_rebase
------------

Rebase a block image file in another location while a guest is running.

Arguments:

- "device": the device's ID, must be unique
- "file": new backing file path

Example:
-> { "execute": "block_rebase", "arguments": { "device": "ide0-hd0", "file": "/storage/new_base.img" }}
<- { "return": {} }
EQMP

hmp-command.hx

    {
        .name       = "block_rebase",
        .args_type  = "drive:s,file:s",
        .params     = "drive file",
        .help       = "rebase drive's backing file",
        .mhandler.cmd = hmp_block_rebase,
    },

STEXI
@item block_rebase
@findex block_rebase
Rebase drive's backing file.
ETEXI

Usage example

Original Disk

New rebased Disk

QMP command

{ "execute": "block_rebase", "arguments": { "device": "ide0-hd0", "file": "/storage/new_base.img" } }

HMP command

(qemu) block_rebase ide0-hd0 /storage/new_base.img