Hard link to root-owned file now fails (since Fedora 19)

[Colin Walters]

On Tue, 2013-07-16 at 15:59 +0100, Richard W.M. Jones wrote:
>  I'm not even sure
> how to do that because we want the atomic behaviour of hard links, and
> we want to have qemu running as a different user (for security, oh the
> irony), so there's no other obvious way to code it.

Can you link to or describe the relevant algorithm/code?  The file
https://github.com/openstack/nova/blob/master/nova/virt/disk/vfs/guestfs.py#L94
doesn't contain an obvious call to link().