[CentOS] XEN images and XFS don't seem to get along

Hello listmates,

It appears that on the second machine in a row (CentOS 5.5, 32 bit) if
I am trying to place a VM into a file located in XFS the machine just
hangs (the host machine, not the VM). If I place the VM in a raw
device or in a file in ext3 all seems to work perfectly. Is that just
a coincidence or is there a reason for this madness?

Thanks.

Boris.