Failed to get shared "write" lock with 'qemu-img info'

When running 'qemu-img info test.qcow2' while test.qcow2 is currently used by a Qemu process, I get the error

qemu-img: Could not open 'test.qcow2': Failed to get shared "write" lock.


Why does displaying information about a disk image need a write lock for the file?

Steps to reproduce:

qemu-img create -f qcow2 test.qcow2 10M
qemu-system-x86_64 -nographic -drive file=test.qcow2
qemu-img info test.qcow2

The above was tested with Qemu version 2.10.0