GELI devices produced with 9.0+ fail when mounted on 8.2, etc?

[Pawel Jakub Dawidek]

On Wed, Oct 19, 2011 at 09:37:33AM -0700, Garrett Cooper wrote:
> On Wed, Oct 19, 2011 at 9:18 AM, Pawel Jakub Dawidek <pjd at freebsd.org> wrote:
> > On Wed, Oct 19, 2011 at 08:30:39AM -0700, Garrett Cooper wrote:
> >> Patch added for the first suggestion here:
> >> http://www.freebsd.org/cgi/query-pr.cgi?pr=161807 . I'll see if I can
> >> get around to the other two sometime before the end of the week.
> >
> > I'm already working on this. Unfortunately 'upgrade' subcommand will be
> > much harder to implement, because in some cases we would need to rewrite
> > the data for the entire provider. I decided not to add upgrade. It also
> > doesn't buy us much. Even after upgrade you cannot switch to new
> > algorithms or to multi-key encryption, etc.
> >
> > Instead I added 'version' subcommand:
> >
> >        geli version [-l]
> >        geli version [prov ...]
> >
> > Examples:
> >
> >        # geli version
> >        kernel: 6
> >        userland: 5
> >
> >        # geli version ada0 gpt/secret
> >        ada0: 5
> >        gpt/secret: 3
> >
> >        # geli version -l
> >        FreeBSD version: highest supported GELI version:
> >        FreeBSD 6.0: 0
> >        FreeBSD 6.1: 0
> >        FreeBSD 6.2: 3
> >        FreeBSD 6.3: 3
> >        FreeBSD 6.4: 3
> >        FreeBSD 7.0: 3
> >        FreeBSD 7.1: 3
> >        FreeBSD 7.2: 3
> >        FreeBSD 7.3: 3
> >        FreeBSD 7.4: 3
> >        FreeBSD 8.0: 3
> >        FreeBSD 8.1: 3
> >        FreeBSD 8.2: 5
> >        FreeBSD 9.0: 6
> 
> Wouldn't it be better to document this in a manpage like I suggested
> so the code could be MFCed easier?

Manual page is in the same place as source code, so it doesn't really
matter if we merge geli.8 or geom_eli.c. I was planing to put this into
manual page as well, but I think that having it only in the manual page
should be enough indeed.

> Also, I like the thought of having a separate subcommand -- version --
> for displaying the version output of a geli image. It seems like:
> 
> geli upgrade md0

You meant 'version' here, right?

> should just upgrade md0 to the latest supported metadata format
> instead of printing out the metadata version, as the implied metadata
> version should be the latest one by default.

Well, as I said, upgrading is often not possible, as it would require
rewrite of all the data, as the code assumes for example that if this is
version X, IV should be calculated this way and if it Y some other way,
etc.

-- 
Pawel Jakub Dawidek                       http://www.wheelsystems.com
FreeBSD committer                         http://www.FreeBSD.org
Am I Evil? Yes, I Am!                     http://yomoli.com
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