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

[Garrett Cooper]

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?

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

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.

Thanks,
-Garrett