Re: Nasty git corruption problem

From: Linus Torvalds
Date: Thu Jul 27 2006 - 17:00:28 EST




On Thu, 27 Jul 2006, Johannes Schindelin wrote:
>
> On Thu, 27 Jul 2006, Linus Torvalds wrote:
>
> > On Thu, 27 Jul 2006, Alan Cox wrote:
> > >
> > > git-lost-found turns up some of the missing stuff that was applied
> > > earliest in the rebase but the other stuff is apparently neither visible
> > > anywhere in the tree or missing (the tree I was rebasing "^^^..." never
> > > shows it nor does the log).
> >
> > Did you try "git-fsck-objects --full"?
> >
> > The git-lost-found script is apparently broken, exactly because it doesn't
> > do a "full".
>
> Of course, I was assuming that nothing like repacking or pruning took
> place after the crash...

That's not the point.

If somebody does a "git rebase", he might be changing the heads that have
already been packed, and replacing them them with heads that have _not_
yet been packed. So the _dangling_ links are the old ones (in the
pack-file), and "git-fsck-objects --full" is needed to see them.

That said, I still don't think Alan sees what he says he sees. Even if
something crashes in the middle of a "git rebase", I think the old head
should have been saved in .git/ORIG_HEAD, for example.

That said, some of the more invasive operations (and "git rebase"
certainly counts) should probably have a few "sync" operations to make
sure that things like ORIG_HEAD really are on disk, so that we would be
able to recreate the tree even _without_ anything like "git-fsck-objects".

Linus
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/