Thus spake Christoph Hellwig ("CH> ") sometime Today...

CH> On Wed, Oct 22, 2003 at 08:22:52AM -0700, Jason Thorpe wrote:
CH> > I don't think that Linux uses a pseudo-device shim layer for
CH> > journaling.
CH>
CH> Indeed.  ext3's journaling is in a journaling block device (JBD)
CH> layer, but despite the name it's not a pseudo-device layer but
CH> more a library of journaling routines for physical block logging.
CH>
CH> > They do, however, use physical block logging (IIRC).
CH>
CH> ext3 and reiserfs do, jfs and xfs don't.

Hm.  Judging by that, perhaps PBL is NOT the wisest move (for the
uninitiated:  jfs and xfs are more stable than either of ext3 or
reiserfs).

I don't quite get why you wouldn't put the layer in the block device
instead of on the disk device overall; if you...write...d'oh.  Okay.
Dumb statement, never mind (just realised, "what about things like
databases which might make use of the raw partition?", and "why not
make it applicable to ALL on-disk filesystems?"  Good point.).


				--*greywolf;
--
NetBSD: Professional power!