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Revision 1.8, Sun Feb 28 18:57:53 2016 UTC (5 years, 7 months ago) by sevan
Branch: MAIN
CVS Tags: HEAD
Changes since 1.7: +3 -3 lines

typo

<?xml version="1.0"?>
<!DOCTYPE webpage
  PUBLIC "-//NetBSD//DTD Website-based NetBSD Extension//EN"
         "http://www.NetBSD.org/XML/htdocs/lang/share/xml/website-netbsd.dtd">

<webpage id="docs-mirror">
  <config param="desc" value="NetBSD Mirror FAQ"/>
  <config param="cvstag"
    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 $"/>

  <head>

    <!-- Copyright (c) 1994-2015
    The NetBSD Foundation, Inc.  ALL RIGHTS RESERVED. -->

    <!--
    ==  created by Martin Husemann
    -->

    <title>Mounting an old FFSv1 file system warning</title>
  </head>

  <sect1>
    <sect2 id="why">
      <title>Why do I get this warning?</title>
      <para>
	Sometimes when mounting a file system, the kernel will output
	the following warning:
	<programlisting>
root on wd0a dumps on wd0b
CGSIZE(fs) miscalculated by one - this file system may have been created by
  an old (buggy) userland, see
  http://www.NetBSD.org/docs/ffsv1badsuperblock.html
root file system type: ffs
	</programlisting>
	or an even more scary version:
	<programlisting>
# 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
	</programlisting>
	which prevents using the disk completely.
      </para>
      <para>
	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.
      </para>
      <para>
      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
      kernel.
      </para>
    </sect2>
    <sect2 id="action">
      <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>
    </sect2>
    <sect2 id="longterm">
      <title>What is the (long term) recommended action to solve the issue?</title>
      <para>
	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.
      </para>
      <para>
        Otherwise:
	back up all your data from this partition, use a modern newfs(8) to
	recreate the filesystem and restore the data.
      </para>
    </sect2>
  </sect1>
</webpage>