Launch QEMU with:

$> x86_64-softmmu/qemu-system-x86_64 -display none -no-user-config \
    -nodefaults -monitor stdio -machine pc,accel=kvm,usb=off \
    -cpu IvyBridge -m 2048 
    -blockdev node-name=node-Base,driver=qcow2,file.driver=file,file.filename=./base.qcow2 \
    -device virtio-blk,drive=node-Base,id=virtio0 \
    -qmp unix:./qmp-sock,server,nowait

=== QMP ===

$> ./qmp-shell -v -p /export/qmp-sock
(QEMU) query-version
{
    "execute": "query-version", 
    "arguments": {}
}
{
    "return": {
        "qemu": {
            "micro": 50, 
            "major": 2, 
            "minor": 12
        }, 
        "package": "v2.12.0-1690-g81e21aa70c-dirty"
    }
}

(QEMU) blockdev-create job-id=job0 options={"driver":"file","filename":"foo.qcow2","size":0

(QEMU) blockdev-create job-id=job1 options={"driver":"qcow2","size":16384,"file":{"driver":"file","filename":"foo.qcow2"}}

(QEMU) blockdev-add driver=qcow2 node-name=node-Foo file={"driver":"file","filename":"foo.qcow2"}

(QEMU) query-named-block-nodes
[...]

            "bps_wr": 0,
            "drv": "qcow2",
            "node-name": "node-Foo",
            "bps": 0,
            "iops": 0,
            "write_threshold": 0,
            "file": "foo.qcow2",
            [...]
        }, 
[...]  
            "bps_wr": 0,                       
            "drv": "qcow2",                    
            "node-name": "node-Base",
            "bps": 0,
            "iops": 0,
            "write_threshold": 0,
            "file": "./base.qcow2",
            [...]
        },  
[...]

=== HMP ===

QEMU 2.12.50 monitor - type 'help' for more information
(qemu) info block -n
node-Foo: foo.qcow2 (qcow2)                    
    Cache mode:       writeback                

#block482: foo.qcow2 (file)                    
    Cache mode:       writeback                

node-Base: ./base.qcow2 (qcow2)                
    Cache mode:       writeback                

#block029: ./base.qcow2 (file)                 
    Cache mode:       writeback                
(qemu)