From: Bryan Schumaker <bjschuma@netapp.com>
Date: Wed, 26 Sep 2012 19:25:52 +0000 (-0400)
Subject: NFS: Remove bad delegations during open recovery
X-Git-Tag: v3.7-rc1~58^2~66
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6938867edba929a65a167a97581231e76aeb10b4;p=pandora-kernel.git

NFS: Remove bad delegations during open recovery

I put the client into an open recovery loop by:
	Client: Open file
		read half
	Server: Expire client (echo 0 > /sys/kernel/debug/nfsd/forget_clients)
	Client: Drop vm cache (echo 3 > /proc/sys/vm/drop_caches)
		finish reading file

This causes a loop because the client never updates the nfs4_state after
discovering that the delegation is invalid.  This means it will keep
trying to read using the bad delegation rather than attempting to re-open
the file.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
CC: stable@vger.kernel.org [3.4+]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
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