Where to start?

[perryh at pluto.rain.com]

> > I'd like to see the ability to run gjournal without reformatting.
> > If you could create a dummy file inside the filesystem, then use
> > that area for the journal, it might be possible ...
>
> I am not sure about gjournal internals but what if a system crash
> occurs in the middle of a transaction and the fs gets corrupted
> and the data, necessary to fix it is in the journal, but you
> cannot access the journal because the file, which contains the
> journal, is on a corrupted fs?

Looking at this as purely a data-integrity problem, and knowing
nothing whatsoever about gjournal internals :)

I would guess that if a way could be found to preallocate the
journal space (as with mkfile(8) in sufficiently-old systems),
and then record its location in a reasonably-secure location
(the superblock?), it could be accessed during recovery without
reference to possibly-corrupt filesystem metadata.