bin/94810: fsck incorrectly reports 'file system marked clean' when lost+found fills up

[Kris Kennaway]

The following reply was made to PR bin/94810; it has been noted by GNATS.

From: Kris Kennaway <kris at obsecurity.org>
To: Bruce Evans <bde at zeta.org.au>
Cc: Kris Kennaway <kris at freebsd.org>, FreeBSD-gnats-submit at freebsd.org,
	freebsd-bugs at freebsd.org
Subject: Re: bin/94810: fsck incorrectly reports 'file system marked clean' when lost+found fills up
Date: Tue, 21 Mar 2006 22:12:41 -0500

 --UlVJffcvxoiEqYs2
 Content-Type: text/plain; charset=us-ascii
 Content-Disposition: inline
 Content-Transfer-Encoding: quoted-printable
 
 On Wed, Mar 22, 2006 at 02:10:03PM +1100, Bruce Evans wrote:
 > On Tue, 21 Mar 2006, Kris Kennaway wrote:
 >=20
 > >>Description:
 > >
 > >In cases of severe filesystem damage, fsck may fill up lost+found:
 > >
 > >[...]
 > >SORRY. NO SPACE IN lost+found DIRECTORY
 > >UNEXPECTED SOFT UPDATE INCONSISTENCY
 > >
 > >
 > >UNREF DIR  I=3D871505  OWNER=3Droot MODE=3D40770
 > >SIZE=3D512 MTIME=3DJan  1 09:59 1970
 > >RECONNECT? yes
 > >
 > >SORRY. NO SPACE IN lost+found DIRECTORY
 > >UNEXPECTED SOFT UPDATE INCONSISTENCY
 > >[...]
 > >
 > >However, when fsck eventually completes it reports
 > >
 > >***** FILE SYSTEM MARKED CLEAN *****
 > >***** FILE SYSTEM WAS MODIFIED *****
 > >
 > >In fact, all of the damage was not repaired since the extra files
 > >could not be reconnected to lost+found, so it is necessary to:
 > >
 > >1) mount and clean out lost+found or move it aside
 > >
 > >2) unmount and rerun fsck to continue recovering lost files.
 > >
 > >3) Repeat until all files have been recovered (may take multiple
 > >iterations)
 >=20
 > Steps 2 and 3 seemed to be unnecessary when I ran fsck with -y.  Then
 > seemed to just delete everything that couldn't be reconnected to
 > lost+found, and fsck's claim to have cleaned the file system seemed
 > to be correct because the deletions worked.
 
 I did run with fsck -y, and ended up having to iterate steps 1-3 a
 total of 7 times before the filesystem was completely clean.
 
 > Another problem with fsck -y is that you have to use it too much because
 > the interactive interface for answering y/n doesn't scale to large file
 > systems with relatively small but absolutely large damage.  fsck -y should
 > only be used for disposable file systems, but even then you might want to
 > try to preserve 2 files without interactively answering y/n up to N*2^32
 > times for the ones you don't care about.
 
 Yes.
 
 Kris
 
 --UlVJffcvxoiEqYs2
 Content-Type: application/pgp-signature
 Content-Disposition: inline
 
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1.4.2.2 (FreeBSD)
 
 iD8DBQFEIMCpWry0BWjoQKURAnmuAKDO7n5h09/DvT7nh81I5iirKl5ENwCaAheP
 jEhJMrDWv11I02B/FaLhSq8=
 =3maG
 -----END PGP SIGNATURE-----
 
 --UlVJffcvxoiEqYs2--