Re: FFSv1 (UFS1) vs FFSv2 (UFS2)

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Thu, 4 Jul 2019 22:25:11 +0200
    From:        Rhialto <rhialto%falu.nl@localhost>
    Message-ID:  <20190704202511.GD11425%falu.nl@localhost>

  | What is "fslevel 5"? fslevel(8) only explains up to level 4. In fact it
  | even claims "Note that FFSv2 file systems are always level 4."

The level is a constructed value which is essentially meaningless.
Currently "level 5" is FFSv2 - and levels 1..4 are all FFSv1 with
different variations from the original 1980 version.
(ie: the manual ought to be updated...)

But if more variations are added to FFSv1 then it will get more levels
(1..5 after the next alteration) and FFSv2 will become level 6...

This level is puerly an artifact of dumpfs and how it interprets the
internal filesystem version/capability indicators - most likely, until
we start making variations on FFSv2 formats, printing the level at all
for FFSv2 is probably a mistake, right now, FFSv2 simply is FFSv2,
whereas FFSv1 has altered over time.   (The "level" is printed for FFSv2
and arbitrarily given a value 1 more than the biggest needed for FFSv1,
simply to make the same printf statement work for both variants).

kre