samba - Jan 2004 - lease broken message

I often get this message in the logs (Samba 3.0.1, SuSE 8.2, Linux 2.4.23,
glibc 2.3.2):

	lease broken - owner pid = <pid of a smbd process>

What does it mean? (kernel oplocks related???)
Is it a linux or samba problem?

Thanks
DB