From c822ed967cba38505713d59ed40a114386ef6c01 Mon Sep 17 00:00:00 2001
From: Joe Thornber <ejt@redhat.com>
Date: Fri, 10 Oct 2014 09:41:09 +0100
Subject: [PATCH] dm thin: grab a virtual cell before looking up the mapping

Avoids normal IO racing with discard.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
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Reading git-format-patch failed