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

[Kris Kennaway]

On Wed, Mar 22, 2006 at 02:10:03PM +1100, Bruce Evans wrote:
> On Tue, 21 Mar 2006, Kris Kennaway wrote:
> 
> >>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=871505  OWNER=root MODE=40770
> >SIZE=512 MTIME=Jan  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)
> 
> 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
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