From: worley@alum.mit.edu (Dale R. Worley)
To: Lucio Crusca <lucio@sulweb.org>
Cc: util-linux@vger.kernel.org
Subject: Re: [BUG] losetup: support for physical devices
Date: Sun, 25 Jan 2015 22:21:09 -0500 [thread overview]
Message-ID: <87mw56jkgq.fsf@hobgoblin.ariadne.com> (raw)
In-Reply-To: <m96ard$qu8$1@ger.gmane.org> (lucio@sulweb.org)
Lucio Crusca <lucio@sulweb.org> writes:
> During a disaster recovery I found that losetup either
>
> 1. does not support creating loop devices that target physical devices. In
> this case I think there exists a compelling reason to support them
> (http://serverfault.com/questions/659484) and this bug report is a wishlist
> bug
>
> or
>
> 2. it does support physical devices, but it is an undocumented feature (at
> least in the manpage) and the warning it issues is misleading beacuse it
> makes you think it doesn't support them ("losetup: /dev/sdc2: warning: file
> smaller than 512 bytes, the loop device maybe be useless or invisible for
> system tools"). In this case this could be a documentation bug.
>
> I haven't tested which of the two possibilities is the real situation, but
> I'm pretty sure you already know.
I don't recall what I've done that convinced me, but I'm *sure* that you
can do
losetup -o [offset] {-f[--show]|loopdev} /dev/sdXXX
This is implicit throughout Linux, because any block device is also a
"file", and can be read/written as such. (You just can't change its
size.)
What command are you executing? What error are you seeing?
Dale
next prev parent reply other threads:[~2015-01-26 3:29 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-14 17:59 [BUG] losetup: support for physical devices Lucio Crusca
2015-01-14 20:08 ` Karel Zak
2015-01-14 20:13 ` Karel Zak
2015-01-26 3:21 ` Dale R. Worley [this message]
2015-01-26 5:06 ` Peter Cordes
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