POSIX semantics dictate that a file deleted while held open by another process remains available through the reference that the process holds until the process dies or closes the file (verify that this is a POSIX thing).
PVFS1 actually attempts to support this semantic.
We will not try to support this in PVFS2. Clients with it open will all of a sudden get ENOFILE or something similar. Too much state must be maintained to provide this functionality (either on client or server side). We're not going to do this sort of thing on the server side, so unless we have communicating clients, we aren't going to get this behavior.