Interfaces for coordinated access in the file system

Distributed applications routinely use the file system for coordination of access and often rely on POSIX consistency semantics or file system lock support for coordination. In this paper we discuss the types of coordination many distributed applications perform and the coordination model they are restricted to using with locks. We introduce an alternative coordination model in the file system that uses extended attribute support in the file system to provide atomic operations on serialization variables. We demonstrate the usefulness of this approach for a number of coordination patterns common to distributed applications.