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Date: Wed, 20 Nov 2002 12:11:17 -0800
From: Patrick Mansfield <patmans@us.ibm.com>
To: Rick Lindsley <ricklind@us.ibm.com>
Cc: linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org
Subject: Re: [BUG] 2.5.47: sysfs hierarchy can begin to disintegrate
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On Wed, Nov 20, 2002 at 01:25:47AM -0800, Rick Lindsley wrote:

> Interesting observation: the megaraid controller has some problem right
> now (suspected to be hardware) wherein its scsi disks appear at boot
> time but then cannot be accessed later and are subsequently detached.
> Since this could well be a little-used and little-tested path, my
> suspicion is that either the megaraid, scsi, or sysfs code has a bug when
> disks are detached.  So far, I've not been able to find one, however, so

Regarding megaraid, Stephen Hemming and Mark Haverkamp posted about
problems, leading to this:

http://marc.theaimsgroup.com/?l=linux-scsi&m=103728900228366&w=2

Generally - the megaraid had problems, where the aic driver did not using
the same disk drives. AFAICT the megaraid caused a problem, and its error
handling is non existent, so it is unable to recover from the problem. I'm
sure Mark or Stephen could provide details.

> I thought I'd report this in case others might know just where to peek.
> Could it be that removing entries from sysfs is done incorrectly in
> some cases?

If you are talking about rmmod your-scsi-adapter, or removing a scsi_device
vi /proc/scsi, yes, there are problems in sysfs and in scsi. None of the
sysfs fixes are in the current bk tree, I assume Pat Mochel needs to push
them (he hasn't been online recently).

We can push a simple scsi fix (via James B), but the scsi sysfs code is not
good, Mike Anderson is working on some patches for that.

-- Patrick Mansfield
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