POSIX semantics dictate that a file opened by a process may continue to be accessed until the subsequent close, even if the file permissions are changed or the file is deleted. This requires that the file system or clients somehow keep up with a list of files that are open, which adds unacceptable state to a distributed file system. In NFS, for example, this is implemented via the ``sillyrename'' approach, in which clients rename a deleted but open file to hide it in the directory tree, then delete the renamed file when the file is finally closed.
In PVFS2 a file that is deleted is removed immediately regardless of open file descriptors. Subsequent attempts to access the file will find that the file no longer exists.
Neill: Is this completely true, or do clients delay removal in pvfs2-client if someone is still accessing?