That's a start, but not quite what I had in mind. I was more thinking of the case that you write 10001000, and then later, you read 10011000 back from the disk

That's a start, but not quite what I had in mind. I was more thinking of the case that you write 10001000, and then later, you read 10011000 back from the disk and the fs panics. The words "checksum", "digest", or "integrity" don't appear in the paper at all. It's probably a case of "in theory the bits you write to the disk are the bits you later read back, in practice they are not"