From: Jeff Layton <jlayton@primarydata.com>
Date: Wed, 16 Jul 2014 14:31:57 +0000 (-0400)
Subject: nfsd: Avoid taking state_lock while holding inode lock in nfsd_break_one_deleg
X-Git-Tag: omap-for-v3.17/fixes-against-rc2~101^2~108
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=02e1215f9f72ad8c087e21a5701bea0ac18fafd4;p=pandora-kernel.git

nfsd: Avoid taking state_lock while holding inode lock in nfsd_break_one_deleg

state_lock is a heavily contended global lock. We don't want to grab
that while simultaneously holding the inode->i_lock.

Add a new per-nfs4_file lock that we can use to protect the
per-nfs4_file delegation list. Hold that while walking the list in the
break_deleg callback and queue the workqueue job for each one.

The workqueue job can then take the state_lock and do the list
manipulations without the i_lock being held prior to starting the
rpc call.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
---

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