Message-ID: <437E215E.30500@tmr.com>
Date: Fri, 18 Nov 2005 13:45:50 -0500
From: Bill Davidsen <davidsen@tmr.com>
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To: Pavel Machek <pavel@ucw.cz>
CC: bart@samwel.tk, linux-kernel@vger.kernel.org
Subject: Re: Laptop mode causing writes to wrong sectors?
References: <20051116181612.GA9231@knautsch.gondor.com> <20051117223340.GD14597@elf.ucw.cz>
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Pavel Machek wrote:
> Hi!
> 
> 
>>let me start by stating that the following is mainly guessed. I may be
>>completely wrong. Still I think you may be interested in my
>>observations, and perhaps you already got similar reports?
>>
>>On my laptop, running 2.6.14, I'm observing some strange file- and
>>filesystem corruptions. First, I thought it may have been caused by an
>>ext3 bug because the first corruption I did observe happened shortly
>>after an ext3 journal replay.
>>
>>I did report this to linux-kernel, but without any helpful response:
>>http://www.ussg.iu.edu/hypermail/linux/kernel/0511.0/0129.html
>>(Subject: ext3 corruption: "JBD: no valid journal superblock found")
>>
>>But now, I got another hint pointing to a possible cause of this
>>problem: I found a file - /usr/lib/libatlas.so.3.0 - which was corrupted
>>by 4k of it being overwritten by a different file, which I recognized. 
>>And that file happened to be an uncompressed manual page.
>>
>>As usually the manual pages are only stored compressed, this must have
>>happened when I actually did look at that manual page, which causes the
>>uncompressed version to be written to a file in /tmp/. And the best is:
>>I actually remember when I did read that man page, and it was while the
>>notebook ran on battery power, which is quite seldom. On battery power,
>>I have laptop mode activated and the hard disk spun down after a short
>>idle time.
>>
>>Why do I think this is related to the corruption? Well, on the one hand,
>>I'm compiling kernels quite often, tracking linus' git repository,
>>and
> 
> 
> Can you try some filesystem test while forcing disk spindowns via
> hdparm?
> 
> It may be bug in laptop mode, or a bug in ide (or something
> related)... trying spindowns without laptopmode would be helpful.
> 
I don't know if it would be helpful, but I run several servers with 
multiple drives, usually 4-5, some of which are in RAID and some aren't, 
and they all spin down and restart without problems many times a day. 
The kernel is 2.6.14.? with one patch to get my unsupported VIA IDE working.

My laptop also has a spindown (five min from memory) and I have yet to 
have a problem with it. Don't know if any of that is "spindowns without 
laptopmode" in a useful sense.

-- 
    -bill davidsen (davidsen@tmr.com)
"The secret to procrastination is to put things off until the
  last possible moment - but no longer"  -me
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