The following reply was made to PR kern/31873; it has been noted by GNATS.

From: YAMAMOTO Takashi <yamt@netbsd.org>
To: gnats-bugs@netbsd.org
Cc: 
Subject: PR/31873 CVS commit: src/sys/ufs/ufs
Date: Sat, 14 Jan 2006 09:09:02 +0000 (UTC)

 Module Name:	src
 Committed By:	yamt
 Date:		Sat Jan 14 09:09:02 UTC 2006
 
 Modified Files:
 	src/sys/ufs/ufs: ufs_lookup.c
 
 Log Message:
 pull freebsd's ufs_lookup.c rev.1.53 and 1.54.  PR/31873.
 
 > ----------------------------
 > revision 1.54
 > date: 2001/08/26 01:25:12;  author: iedowse;  state: Exp;  lines: +30 -12
 > When compacting directories, ufs_direnter() always trusted DIRSIZ()
 > to supply the number of bytes to be bcopy()'d to move an entry. If
 > d_ino == 0 however, DIRSIZ() is not guaranteed to return a sensible
 > length, so ufs_direnter could end up corrupting a directory during
 > compaction. In practice I believe this can only happen after fsck_ffs
 > has fixed a previously-corrupted directory.
 >
 > We now deal with any mid-block unused entries specially to avoid
 > using DIRSIZ() or bcopy() on such entries. We also ensure that the
 > variables 'dsize' and 'spacefree' contain meaningful values at all
 > times. Add a few comments to describe better this intricate piece
 > of code.
 >
 > The special handling of mid-block unused entries makes the dirhash-
 > specific bugfix in the previous revision (1.53) now uncecessary,
 > so this change removes it.
 >
 > Reviewed by:  mckusick
 > ----------------------------
 > revision 1.53
 > date: 2001/08/22 01:35:17;  author: iedowse;  state: Exp;  lines: +2 -2
 > When compressing directory blocks, the dirhash code didn't check
 > that the directory entry was in use before attempting to find it
 > in the hash structures to change its offset. Normally, unused
 > entries do not need to be moved, but fsck can leave behind some
 > unused entries that do. A dirhash sanity panic resulted when the
 > entry to be moved was not found. Add a check that stops entries
 > with d_ino == 0 from being passed to ufsdirhash_move().
 
 
 To generate a diff of this commit:
 cvs rdiff -r1.71 -r1.72 src/sys/ufs/ufs/ufs_lookup.c
 
 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.