NILFS2 is upstream in Linux - the log structure means snapshots happen for free on every disk operation, so you can get point-in-time rollback without needing t

NILFS2 is upstream in Linux - the log structure means snapshots happen for free on every disk operation, so you can get point-in-time rollback without needing to manually create disk snapshots. It does require a userspace daemon running to compact the log, though.