From: Peng Tao <bergwolf@gmail.com>
Date: Mon, 3 Jun 2013 13:58:15 +0000 (+0800)
Subject: staging/lustre: silence lockdep warning in ll_md_blocking_ast
X-Git-Tag: omap-for-v3.11/fixes-for-merge-window~76^2~333
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b1d2a127a98c2724129218eccd9431d342898da8;p=pandora-kernel.git

staging/lustre: silence lockdep warning in ll_md_blocking_ast

Got bellow lockdep warning during tests. It is false alarm though.

[ 1184.479097] =============================================
[ 1184.479187] [ INFO: possible recursive locking detected ]
[ 1184.479277] 3.10.0-rc3+ #13 Tainted: G         C
[ 1184.479355] ---------------------------------------------
[ 1184.479444] mkdir/2215 is trying to acquire lock:
[ 1184.479521]  (&(&dentry->d_lock)->rlock){+.+...}, at: [<ffffffffa06cc27c>] ll_md_blocking_ast+0x55c/0x655 [lustre]
[ 1184.479801]
but task is already holding lock:
[ 1184.479895]  (&(&dentry->d_lock)->rlock){+.+...}, at: [<ffffffffa06cc1b1>] ll_md_blocking_ast+0x491/0x655 [lustre]
[ 1184.480101]
other info that might help us debug this:
[ 1184.480206]  Possible unsafe locking scenario:

[ 1184.480300]        CPU0
[ 1184.480340]        ----
[ 1184.480380]   lock(&(&dentry->d_lock)->rlock);
[ 1184.480458]   lock(&(&dentry->d_lock)->rlock);
[ 1184.480536]
 *** DEADLOCK ***

[ 1184.480761]  May be due to missing lock nesting notation

[ 1184.480936] 4 locks held by mkdir/2215:
[ 1184.481037]  #0:  (sb_writers#11){.+.+.+}, at: [<ffffffff811531a9>] mnt_want_write+0x24/0x4b
[ 1184.481273]  #1:  (&type->i_mutex_dir_key#3/1){+.+.+.}, at: [<ffffffff81144fce>] kern_path_create+0x8c/0x144
[ 1184.481513]  #2:  (&sb->s_type->i_lock_key#19){+.+...}, at: [<ffffffffa06cc180>] ll_md_blocking_ast+0x460/0x655 [lustre]
[ 1184.481778]  #3:  (&(&dentry->d_lock)->rlock){+.+...}, at: [<ffffffffa06cc1b1>] ll_md_blocking_ast+0x491/0x655 [lustre]
[ 1184.482050]

Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

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