Striping is a technique that distributes file content over multiple storage servers and thereby enables parallel access. In order to be able to provide a consistent view across file data and metadata operations, the file system has to track the layout of the file and know where the file ends and where it contains gaps. In this paper, we present a light-weight protocol for maintaining a consistent notion of a file's layout that provides POSIX semantics without restricting concurrent access to the file. In an evaluation, we show that the protocol scales and elicit its corner cases.