Lease A with token 1 expires and B obtains token 2. A resumes with a late write, but a resource that has already seen token 2 rejects token 1.

Locks and leases tame concurrent writers

Locks and leases coordinate access to shared resources, but their failure behavior depends on the implementation. Here the concern is exclusive writers; locks can also have shared modes. A lease adds a bounded validity period. Neither a familiar name nor a timeout alone proves that a delayed writer cannot damage data after another writer takes over. ...

October 4, 2026 · 6 min · XB Field Notes