[Ocfs2-devel] [PATCH] ocfs2/dlm: avoid incorrect bit set in refmap on recovery master

[Joel Becker]

On Fri, Jul 30, 2010 at 04:14:44PM +0800, Wengang Wang wrote:
> In the following situation, there remains an incorrect bit in refmap on the
> recovery master. Finally the recovery master will fail at purging the lockres
> due to the incorrect bit in refmap.
> 
> 1) node A has no interest on lockres A any longer, so it is purging it.
> 2) the owner of lockres A is node B, so node A is sending de-ref message
> to node B.
> 3) at this time, node B crashed. node C becomes the recovery master. it recovers
> lockres A(because the master is the dead node B).
> 4) node A migrated lockres A to node C with a refbit there.
> 5) node A failed to send de-ref message to node B because it crashed. The failure
> is ignored. no other action is done for lockres A any more.
> 
> For mormal, re-send the deref message to it to recovery master can fix it. Well,
> ignoring the failure of deref to the original master and not recovering the lockres
> to recovery master has the same effect. And the later is simpler.
> 
> Signed-off-by: Wengang Wang <wen.gang.wang at oracle.com>
> Acked-by: Srinivas Eeda <srinivas.eeda at oracle.com>

This patch is now in the fixes branch of ocfs2.git.

Joel

-- 

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 "When you learn how to listen, ANYONE can be your teacher."

Joel Becker
Consulting Software Developer
Oracle
E-mail: joel.becker at oracle.com
Phone: (650) 506-8127