[Qemu-discuss] Is locking option available now?

[Han Han]

I create backing file with 'locking=off', but it seems the locking is
enabled:
On *qemu-2.10*
# qemu-img create -b 'json:{"file": {"driver": "file", "filename":
"/var/lib/libvirt/images/V.qcow2", "*locking*": "*off*"}}'
/var/lib/libvirt/images/a.qcow2 -f qcow2
Formatting '/var/lib/libvirt/images/a.qcow2', fmt=qcow2 size=8589934592
backing_file=json:{"file": {"driver": "file",, "filename":
"/var/lib/libvirt/images/V.qcow2",, "locking": "off"}} cluster_size=65536
lazy_refcounts=off refcount_bits=16

Then checking if locking works:
# qemu-kvm /var/lib/libvirt/images/a.qcow2

VNC server running on ::1:5900

# qemu-img info /var/lib/libvirt/images/a.qcow2
qemu-img: Could not open '/var/lib/libvirt/images/a.qcow2': Failed to get
shared "write" lock
Is another process using the image?

It looks "*locking=off*" not worked. So is this option available now? In
which version this feature will be supported?

-- 
Han Han
Quality Engineer
Redhat.

Email: h...@redhat.com
Phone: +861065339333