Re: clearing bogus journal

[Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>]

> On Tue, Aug 18, 2009 at 09:14:47PM +0900, Izumi Tsutsui wrote:
> > > A second question is whenever fsck_ffs should do minimum checks against
> > > the log integrity, and ask for help if it finds a problem. My guess is 
> > > that
> > > it should propose to clear the log flag(s) and do a "normal" ffs check in
> > > such a case. Any idea on what proper behavior of fsck_ffs would be
> > > with log ?
> > 
> > If old level formats don't support journal at all,
> > I think "fsck_ffs -c4" should explicitly wipe out
> > unused wapbl related fields in converted FFSv2-layout superblock.
> 
> Sure. My question was more about already -c4 filesystem, with an
> active but corrupted journal. I think fsck should be able to detect and
> bring the filesystem back in a mountable state.

Does it happen on plain -c4 filesystem created by
newfs(8)? (not converted by fsck_ffs -c4)

"unrecognized wapbl type" problem could happen as noted PR kern/39924,
and in that case we should fix kernel to allow mount such fs readonly.
(fsck_ffs(8) can fix it)

If "unknown journal type" error could also happen after crash,
it's better to provide some tools to fix it, but I have a feeling
that such feature should be enabled by some explicit option.
(I'm not sure if we will add other journal types in future though)

If "unknown journal type" could only happen on file system converted
by fsck_ffs(8), I think fixing -c4 is enough.
---
Izumi Tsustui