kern/93942: panic: ufs_dirbad: bad dir

[Yarema]

The following reply was made to PR kern/93942; it has been noted by GNATS.

From: Yarema <yds at CoolRat.org>
To: Robert Watson <rwatson at FreeBSD.org>
Cc: FreeBSD-gnats-submit at freebsd.org, FreeBSD-current at freebsd.org,
  David Rhodus <drhodus at machdep.com>,
  Dennis Koegel <amf at hobbit.neveragain.de>,
  Martin Machacek <m at m3a.net>, Kris Kennaway <kris at obsecurity.org>,
  Dmitry Pryanishnikov <dmitry at atlantis.dp.ua>,
  Pawel Jakub Dawidek <pjd at freebsd.org>
Subject: Re: kern/93942: panic: ufs_dirbad: bad dir
Date: Thu, 02 Mar 2006 23:39:45 -0500

 --On March 3, 2006 3:51:45 AM +0000 Robert Watson <rwatson at FreeBSD.org> 
 wrote:
 
 >
 > On Thu, 2 Mar 2006, Yarema wrote:
 >
 >> options	UFS_EXTATTR
 >> options	UFS_EXTATTR_AUTOSTART
 >
 > If you disable just UFS_EXTATTR_AUTOSTART, does the panic go away?  The
 > autostart routine relies on reading directory data (or at least,
 > performing lookups) during the mount process.  While it shouldn't be
 > running on UFS2, it could be that it is, and if something has changed in
 > the mount process so that reading directories that early is no longer
 > functional, it could be that this causes an incorrect reporting of
 > on-disk corruption (i.e., it could be a data structure initialization
 > problem or the like).
 >
 > Robert N M Watson
 
 Damn, I just reformatted the corrupt partition so I can no longer try this. 
 But as per Dmitry's suggestion before newfs wiped it all I did a:
 
 mount -r /home
 cat /home > /tmp/ar0s1e.ino2
 umount /home
 mount -r /dev/twed0s1e /home
 cat /home > /tmp/twed0s1e.ino2
 umount /home
 
 Where ar0s1e is the corrupt slice and the dir is 17408 bytes in size and 
 there seems to be a huge chunk of mostly null data following the entry for 
 lost+found.  twed0s1e is where I backed up the /home fs and the dir in a 
 more reasonable 1024 bytes in size.  Both files can be found at 
 <http://yds.CoolRat.org/freebsd/> along with an archive of my KERNCONF 
 files containing a short README explaining how I manage my KERNCONFs.
 
 -- 
 Yarema