Janne,
ZFS includes the sector number in the checksum input because that
provides a safeguard against any form of disk breakdown.
Most filesystems except for ZFS are susceptible to this kind of error
because either it's not checksummed, or the checksums are locally stored
so data relocations wouldn't be caught (and Karel's is something in
between as checksums are stored separately).
The purpose is to add data integrity guarantees. This is not "how it is
done" in filesystems that not are intended to provide such guarantees
anyhow. The risk there is that in extremely rare cases, parts or whole
of files may be swapped, and that is not OK for "high value data".
On 2016-02-01 18:40, Janne Johansson wrote:
I did not oppose adding the sector number, just the "idea" that
internal
relocations would make this number change.
If it did, then everything would break for all filesystems, so that is
obviously not how it is done.
