Subject: Re: FFS journal
To: Manuel Bouyer <bouyer@antioche.eu.org>
From: Bill Studenmund <wrstuden@netbsd.org>
List: tech-kern
Date: 07/05/2006 13:31:19
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On Wed, Jul 05, 2006 at 10:20:21PM +0200, Manuel Bouyer wrote:
> On Wed, Jul 05, 2006 at 12:49:54PM -0700, Jason Thorpe wrote:
> >=20
> > On Jul 5, 2006, at 12:01 PM, Manuel Bouyer wrote:
> >=20
> > >How can we mont it read-only right now ?
> >=20
> > Right now we have ordered MD writes.  With a journal, you generally =20
> > don't do that
>=20
> I think I explicitely said that we need to keep ordered MD writes for this

Uhm, the idea of a journal is that you no longer have to order MD writes.=
=20
As I understand it, that is the _point_. To retain ordering when we have a=
=20
journal is defeating the purpose.

> > (that's what you have the journal for!)
>=20
> It's also to make fsck faster. I'd prefer to have at last the option to
> keep ordered writes and have fsck deal with the replay, so that we're
> guaranteed to always be able to read the filesystem (and eventually repair
> it) even if the journal is corrupted.

If you lose the journal, you need to do a full fsck before touching the=20
file system.

I think journal playing code in-kernel is needed to support a journaled=20
root. But other than that, have fsck fix things up.

Take care,

Bill

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