Using concurrent relational logic with helpers for verifying the AtomFS file system
Mo Zou, Haoran Ding, Dong Du, Ming Fu, Ronghui Gu, Haibo Chen · 2019
Concurrent file systems are pervasive but hard to correctly implement and formally verify due to nondeterministic interleavings. This paper presents AtomFS, the first formally-verified, fine-grained, concurrent file system, which provides linearizable interfaces to applications. The standard way to prove linearizability requires modeling linearization point of each operation---the moment when its effect becomes visible atomically to other threads. We observe that path inter-dependency, where one operation (like rename) breaks the path integrity of other operations, makes the linearization point external and thus poses a significant challenge to prove linearizability.