From mboxrd@z Thu Jan  1 00:00:00 1970
From: quidame@poivron.org
Date: Thu, 28 Jun 2012 10:39:50 +0000
Subject: add loop device backing file in udev database
Message-Id: <5deaf9514b7dafac35d4cdef91260ba1@poivron.org>
List-Id: <linux-hotplug.vger.kernel.org>
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To: linux-hotplug@vger.kernel.org

Hi,

Since kernel 2.6.37, some infos are available in /sys for associated 
loop devices, especially the backing file. Is it poosible to introduce 
the BACKING_FILE variable for associated loop devices ?

This sample

ACTION="add|change", \
         KERNEL="loop?*", \
         SUBSYSTEM="block", \
         TEST="%S/block/%k/loop/backing_file", \
         PROGRAM="/bin/cat %S/block/%k/loop/backing_file", \
         ENV{BACKING_FILE}="%c"

works fine.

I have already send a bug report to the Debian maintainer 
(http://bugs.debian.org/cgi-bin/bugreport.cgi?bugg1546) who has 
recommended me to directly propose this change to the upstream 
maintainer.

Thanks
quidame