> Hmm... normally we'd supply sbi->s_csum_seed as the second argument so > that the metadata checksum value also has the fs uuid stamped into it. I have thought about using sbi->s_csum_seed and was a little hesitant because it involves adding more complexity to e2fsprogs to handle cases like changing uuid or turning off metadata_csum. After thinking more about this, I think it is doable. > Even if you dismiss that, we usually follow the convention of > initializing the crc32c calculation with (~0U), not (0U), to strengthen > crc32c's ability to detect zeroes being injected at the start of the > stream. Agreed, using ~0 is definitely better than 0.
