Subject: Re: ffs compatibility patches
To: Darrin B. Jewell <>
From: Manuel Bouyer <>
List: tech-kern
Date: 01/06/2004 21:27:46
On Mon, Jan 05, 2004 at 04:17:23PM -0500, Darrin B. Jewell wrote:
> I have developed ffs compatibility patches for fsck and the kernel
> which I would like to commit shortly.  These patches should address
> the recent ffs compatibility problems introduced with the addition
> of ffsv2 to the NetBSD kernel.
> I have introduced the '-c 4' option to fsck_ffs which performs
> the superblock upgrade used by the current version of ffs.
> Without this option, neither fsck nor the kernel will
> automatically upgrade the superblock.
> This should fix the corruption of apple ufs filesystems, and allow
> a filesystem to be shared between netbsd 2.0 and netbsd 1.6 without
> causing fsck problems for either.
> Note that the patches restore the stricter alternate superblock
> comparision used for un-upgraded filesystems.  Filesystems which are
> upgraded with 'fsck_ffs -c 4' will allow a looser comparison of the
> superblock to help enable future compatibility.  After these patches,
> -current users who have a partially upgraded superblock that does not
> yet use the new flags, will need to again run fsck_ffs -b 32.  This
> should only affect -current kernel users.  Any users who are upgrading
> from or downgrading to old released versions should have no problems
> running the old or the new fsck on their filesystems.
> The patches may currently be found in gnats in the following two prs:
>   port-macppc/23925  "fsck_ffs corrupts APPLE_UFS filesystems"
>   port-macppc/23926  "kernel APPLE_UFS support needs review"

Looks good , but I didn't look at them twice :)
However, I think there should also be an option to newfs to create
filesystems compatible with the old format.

> These patches will also fix the problems discussed in these prs:
>   kern/21404 "new kernel breaks file system for old kernels"
>   kern/21283 "current FFS (not v2) incompatible with older NetBSD releases"

I though I had closed kern/21283 , I daily use a ZIP floppy between a current
i386 and 1.6.1 alpha without problems since I commited some changes for
this ...

Manuel Bouyer <>
     NetBSD: 24 ans d'experience feront toujours la difference