| I hacked up a (not SMP-safe!) compressed loopback driver for a now-forgotten startup's "bootable business card" rescue disk. Over a year later I received an email from someone wanting to use it who was trying to port it forward. When someone on my team started playing with this new Knoppix thing I was blown away: not just a rescue disk but a full-on distribution! Moral: publish your hacks! Hey, I found the email: Date: Sat, 3 Jun 2000 02:17:47 +0200
From: Klaus Knopper <knopper@linuxtag.de>
To: Paul.Russell@linuxcare.com.au
Subject: Compressed Loopback device
Message-ID: <20000603021747.A17496@linuxtag.de>
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Sender: rusty@linuxcare.com.au Hello Mr. Russel, I'm trying to use your compressed loopback device as found on the LinuxCare
rescue CD-Rom, for my selfconfiguring Linux distribution that runs entirely
from CD (including XFree and KDE). Unfortunately, the version that I got of the cloop device seems to act quite
instable (of course I recompiled it for Kernel 2.2.15, which should not
differ all too much from 2.2.14). I blame it on the fact that the file handle
is being read from stdin of insmod, but it could be something different. With an SMP-Kernel, cloop.o crashes immediately on insmod when calling
fget(0). With a non-SMP kernel, it kills the kernel block buffer system,
shutting down all other block devices as well, when accessing certain large
files on an ext2 filesystem within the compressed block device file. It seems
that the ll_rw_block() routine fails in that case, and wait_for_buffer() never
returns, locking up something in the kernel block buffer management. Do you maybe have a newer version of cloop that I can start working on?
Btw, I found and fixed the bug in extract_compressed_fs.c, but I think it
would really be nice if the sources for the whole package could be downloaded
from LinuxCare somewhere without having to get the whole CD-Rom image. If I find the cloop lockup-bug before you have time to answer, I will send a
patch. Regards -Klaus Knopper
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Klaus Knopper LinuxTag 2000 - Europes largest Linux Expo |