PUBLIC "-//NetBSD//DTD Website-based NetBSD Extension//EN"
<config param="desc" value="NetBSD Mirror FAQ"/>
value="$NetBSD: ffsv1badsuperblock.xml,v 1.8 2016/02/28 18:57:53 sevan Exp $"/>
<config param="rcsdate" value="$Date: 2016/02/28 18:57:53 $"/>
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The NetBSD Foundation, Inc. ALL RIGHTS RESERVED. -->
== created by Martin Husemann
<title>Mounting an old FFSv1 file system warning</title>
<title>Why do I get this warning?</title>
Sometimes when mounting a file system, the kernel will output
the following warning:
root on wd0a dumps on wd0b
CGSIZE(fs) miscalculated by one - this file system may have been created by
an old (buggy) userland, see
root file system type: ffs
or an even more scary version:
# mount /home
mount_ffs: /dev/raid2a on /home: incorrect super block
ERROR: cylinder group size mismatch: fs_cgsize = 0x4800, fs->fs_cgsize = 0x4000, CGSIZE(fs) = 0x4003
which prevents using the disk completely.
This originally was suspected to happen when the file system has been created with a very
ancient newfs utility - the bug causing this mis-setup was fixed in revision 1.96
of src/sbin/newfs/mkfs.c, on January 11, 2006.
But later <ulink url="http://gnats.NetBSD.org/50070">analysis</ulink>
resulted in a fix of the slightly over-eager sanity check done by the
<title>Is emergency action needed?</title>
<para>If you get the first form and can still mount the file system: no,
you can just ignore the issue.
The second variant of the error prevents usage of the filesystem,
so you need to upgrade your kernel (see below).</para>
<title>What is the (long term) recommended action to solve the issue?</title>
Assuming the affected file system is not actually of the ancient
(broken) variant created with a pre-2006 binary: install a newer
kernel. You should only see this message on some versions of
-current, so upgrading to a recent -current kernel (newer than
october 22, 2015) should fix it.
back up all your data from this partition, use a modern newfs(8) to
recreate the filesystem and restore the data.