Re: kern/48449: y2038 shortcomings of ffsv1

[Joerg Sonnenberger <joerg%bec.de@localhost>]

On Wed, Jun 16, 2021 at 08:35:01PM +0000, Jaromír Doleček wrote:
> The following reply was made to PR kern/48449; it has been noted by GNATS.
> 
> From: =?UTF-8?B?SmFyb23DrXIgRG9sZcSNZWs=?= <jaromir.dolecek%gmail.com@localhost>
> To: "gnats-bugs%NetBSD.org@localhost" <gnats-bugs%netbsd.org@localhost>
> Cc: 
> Subject: Re: kern/48449: y2038 shortcomings of ffsv1
> Date: Wed, 16 Jun 2021 22:33:27 +0200
> 
>  Le mer. 16 juin 2021 =C3=A0 11:40, Robert Elz <kre%munnari.oz.au@localhost> a =C3=A9c=
>  rit :
>  >  All of this for a pointless change...
>  >
>  >  [On my bizarre suggestion to steal the upper 2 bits from the
>  >  nanoseconds field]:
>  
>  I really like the suggestion for reusing the unused upper 2 bits for
>  the time for FFSv1 filesystems. It's guaranteed to be unused on all
>  existing filesystems, and does not require any changes to existing
>  inodes nor new superblock fields. Perfect for when you fire up some
>  old forgotten VM in 30 years.

The easiest way would actually be to use the sign bit as flag and switch
to a different time encoding iff it is set.

Joerg