Multiple revisions of an encoded data slice can be stored in a distributed storage unit. Before writing a new revision of an encoded data slice to storage, the distributed storage unit can invoke a write lock for all encoded data slices having the same slice name as the slice being currently written. The slice being currently written can be stored in temporary storage, and a rollback timer started. If a commit command is received before expiration of the rollback timer, the currently written slice can be permanently stored and made accessible for read requests. If the rollback timer expires prior to the storage unit receiving a commit command, however, a previously stored revision will be used.