Subject: Re: Migration question( OpenBSD 2.9 -> NetBSD -current)
To: Luke Mewburn <>
From: BOUWSMA Beery <>
List: current-users
Date: 08/06/2002 00:30:32
[IPv6-only mail address; remove the obvious in case of need to reply]
[This is a rather old message I'm replying to, but it seems to be
 relevant again...]

> A while ago I took pains to ensure that the ffs superblock in NetBSD
> would be compatible with FreeBSD's and OpenBSD's, so that explains why
> the mount worked ok.  I also took a brief look at other changes in ffs
> on those systems at the time and I don't recall anything that would be
> done to make things difficult.

> If possible, I would like for NetBSD to be able to mount FreeBSD and
> OpenBSD ffs partitions (there really should be no need for gratitious
> incompability here, especially if we're not using newer features such
> as snapshots on the partition, as all three systems are relatively

Okay, things seem to have worked, more or less, until FreeBSD-current
decided to do something to the superblock, which broke compatibility
with NetBSD (and FreeBSD-stable before a certain date).  This happened
like a month or so ago, and FreeBSD-stable had to have its `fsck'
changed to be compatible.

But a quick single-user boot into NetBSD-current of, hmmm, two months
ago, makes it appear that those filesystems that I share between all
of NetBSD-current and FreeBSD, -current and -stable, no longer can
be fsck'ed by NetBSD.  There's some bit of discussion a couple weeks
ago on the FreeBSD mailing lists about this change.

I looked at my source tree for NetBSD-current's fsck and didn't
see any obvious changes.  If I'm not mistaken, the change that
needs to be made, which limits the superblock/alternate-superblock
comparison to only the fields that shouldn't differ, is the FreeBSD
MFC 1.30 to src/sbin/fsck/setup.c in 2002/06/24, which
diff should be relatively easy to munge into the NetBSD
src/sbin/fsck_ffs/setup.c -- so that one doesn't need to invoke
`fsck_ffs -b #' to attain satisfaction.

Are there plans to attempt to remain compatible with the newer
UFS features that recent FreeBSD-current has incorporated, such
as the above FreeBSD-stable patch?

(I might try shoehorning this patch in myself, but it'll be a
spell before I'm able to boot into NetBSD and take a stab at it)

barry bouwsma