A common occurrence in PVFS1 is that one client will create a file that is subsequently accessed by a number of other clients. It is important semantically that it is never the case that an explicit attempt to access a recently created file fails because of our caching policy. Because of this, any time a file system object is explicitly referenced that is not in the cache, we will assume that the cache is not up to date (regardless of the timeout values described above) and attempt to obtain metadata for the object. Only if this fails will we return an error indicating that the object does not exist.
This is an instance of an implicit hint from the user that something in the cache might not be up to date. We should consider where other such hints occur.
Any time a request is received on a client to operate on a file system object that is not known to the client-side cache, the client will attempt to retrieve metadata for the object.