If I do "cp somewhta somewhere" an at the same time I run
repquota and/or quotacheck the quota tools go into sate "D"
(uninterruptible  sleep).

I've tried it on variuos hardware platforms (i386 with
different scsi and ide adaptors).

On the kernel-list comes a patch for 2.2.6 that solves this
problem but it isn't official. Here is the header of this
posting:

List:     linux-kernel
Subject:  Re: sync problem in 2.2.5
From:     Jan Kara <jack.mff.cuni.cz>
Date:     1999-04-20 22:15:58

It occurs in RedHat Linux 5.2 and 6.0.

In the official Debian 2.1 Linux Dist. this error occurs
not.