From: Yan, Zheng <zheng.z.yan@intel.com>
Date: Fri, 12 Apr 2013 08:11:10 +0000 (+0800)
Subject: ceph: take i_mutex before getting Fw cap
X-Git-Tag: omap-for-v3.10/dt-fixes-for-merge-window~26^2~92
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=37505d5768b9389a5ef7bc1efa465d4484a5462e;p=pandora-kernel.git

ceph: take i_mutex before getting Fw cap

There is deadlock as illustrated bellow. The fix is taking i_mutex
before getting Fw cap reference.

      write                    truncate                 MDS
---------------------     --------------------      --------------
get Fw cap
                          lock i_mutex
lock i_mutex (blocked)
                          request setattr.size  ->
                                                <-   revoke Fw cap

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
---

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