This is a patch for scan_ffs to make it find UFS2 partitions.
The following test data represents a sample of the various disks
available to me at this time. All of the tests are on 6.3 amd64.
I haven't updated to 6.4 or snapshots on this machine.
By design, scan_ffs can only find intact first superblocks.
Backup superblocks do not contain enough data to find
the partition start.
Deducing partition start addresses from backup superblocks
requires interpreting cylinder group data which would be a
The standard warning: if this code melts your machine or makes
you turn purple, I told you so.