From: Sunil Mushran <sunil.mushran@oracle.com>
Date: Thu, 21 Jan 2010 18:50:03 +0000 (-0800)
Subject: ocfs2: Prevent a livelock in dlmglue
X-Git-Tag: v2.6.33-rc8~38^2~7
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a19128260107f951d1b4c421cf98b92f8092b069;p=pandora-kernel.git

ocfs2: Prevent a livelock in dlmglue

There is possibility of a livelock in __ocfs2_cluster_lock(). If a node were
to get an ast for an upconvert request, followed immediately by a bast,
there is a small window where the fs may downconvert the lock before the
process requesting the upconvert is able to take the lock.

This patch adds a new flag to indicate that the upconvert is still in
progress and that the dc thread should not downconvert it right now.

Wengang Wang <wen.gang.wang@oracle.com> and Joel Becker
<joel.becker@oracle.com> contributed heavily to this patch.

Reported-by: David Teigland <teigland@redhat.com>
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
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