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Date: Fri, 08 Apr 2011 18:23:23 +0300
From: Andriy Gapon <avg@FreeBSD.org>
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To: Andrew Duane <aduane@juniper.net>
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Cc: "freebsd-fs@freebsd.org" <freebsd-fs@FreeBSD.org>,
	FreeBSD Hackers <freebsd-hackers@FreeBSD.org>, freebsd-scsi@FreeBSD.org
Subject: Re: retry mounting with ro when rw fails
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on 08/04/2011 15:36 Andrew Duane said the following:
> What I was hoping to do was design a better mechanism for passing that R/O
> detection from the device to the filesystem code. Our implementation uses a
> platform sysctl that checks the incoming device name against some hardware or
> software settings. Ick. I don't know enough about device/GEOM calls to do it
> better though.

I am actually not aware of any way to inquiry write-protection status from
hardware.  There are distinct SCSI sense codes for that, but you get them only
after a failed write attempt.

But there are many things that I don't know about...

-- 
Andriy Gapon