Path: utzoo!attcan!uunet!lll-winken!ames!mailrus!um-math!hyc
From: hyc@math.lsa.umich.edu (Howard Chu)
Newsgroups: comp.os.minix
Subject: Re: Problem with large hard disk partition (ATARI)
Message-ID: <545@stag.math.lsa.umich.edu>
Date: 15 Jan 89 05:12:38 GMT
References: <1226@uwovax.uwo.ca>
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Reply-To: hyc@math.lsa.umich.edu (Howard Chu)
Organization: University of Michigan Math Dept., Ann Arbor
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In article <1226@uwovax.uwo.ca> 7103_300@uwovax.uwo.ca (Eric Smith) writes:
>
>   A friend recently ran into a problem installing Minix on his
>Megafile 60. Mounting a large (32Mb) partition followed by a smaller
>one produced a "file table overflow" message. Trying to mount both
>of them from /etc/rc produced a fatal file system panic. Apparently
>mount reads a lot of information from disk, and a 32Mb partition's
>super block info, etc. fills up the buffer cache. We recompiled
>Minix with a bigger buffer cache, and the problem went away.

I encountered this problem, or a similar one, but the circumstances
are too odd for me to believe it's really the size of the buffer cache
that's the culprit.

I have a 47 meg partition. I had to change mkfs before I could actually
use it, but I was then able to mount it with no trouble. I added it into
my /etc/rc, and went away. Next time I tried to boot Minix, filesystem
panic, out of buffers (20). Hmmm....

I interrupt after booting, so /etc/rc doesn't get executed. Ok, fine.
Mount the partition, boom. Panic. Reboot, mount a floppy, try to see
what's happening. (All of my sources are on that 47 meg partition. If
I can't mount it, I'm in Big Trouble....) Mount the partition. Ok. No
crash. What happened?

Turns out that I can mount the big partition with no trouble, if I mount
a small one first. Why is this, I wonder. Then I can continue to mount
any number of small partitions. But, if I just mount the small partition,
followed by the big one, and then try to unmount the small one, panic. Same
as before. Haven't examined the code yet, but I suspect a signed/unsigned
short problem...
--
  /
 /_ , ,_.                      Howard Chu
/ /(_/(__                University of Michigan
    /           Computing Center          College of LS&A
   '              Unix Project          Information Systems