Comment 2 for bug 680138

Note, the subject of the bug says:
   if cwd is not same filesystem as home

I can reproduce this on a lucid server I have access to , so I suspect its also a bug on maverick.

the bug is actually in zsync, which is (i think) trying to create a hardlink.

$ df / /home
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda8 20650996 8295264 11306692 43% /
/dev/sda5 100791896 62157596 33514292 65% /home

$ cd /tmp
$ zsync http://cdimage.ubuntu.com/daily/current/natty-alternate-i386.iso.zsync -o /home/smoser/foo.iso
#################### 100.0% 541.5 kBps DONE

No relevent local data found - I will be downloading the whole file. If that's not what you want, CTRL-C out. You should specify the local file is the old version of the file to download with -i (you might have to decompress it with gzip -d first). Or perhaps you just have no data that helps download the file
rename: Invalid cross-device link
rename: Invalid cross-device link

This can be worked around in testdrive easily enough by changing the working directory to the target directory before invoking zsync.