Date: Mon, 11 Apr 2011 16:27:03 +1000
From: Dave Chinner <david@fromorbit.com>
To: "J. R. Okajima" <hooanon05@yahoo.co.jp>
Cc: Peter Zijlstra <peterz@infradead.org>, Al Viro <viro@zeniv.linux.org.uk>,
        Christoph Hellwig <hch@infradead.org>, Nick Piggin <npiggin@suse.de>,
        linux-kernel@vger.kernel.org
Subject: Re: Q. locking order of dcache_lru_lock
Message-ID: <20110411062703.GC21395@dastard>
References: <9769.1302268831@jrobl>
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 <29946.1302498571@jrobl>
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On Mon, Apr 11, 2011 at 02:09:31PM +0900, J. R. Okajima wrote:
> 
> Peter Zijlstra:
> > On Fri, 2011-04-08 at 22:20 +0900, J. R. Okajima wrote:
> > >=20
> > > When spin_trylock(&dentry->d_lock) successfully acquired d_lock, does
> > > the violation of locking order happen (or a deadlock, in worse case)?=20
> >
> > No, since a trylock never actually blocks a deadlock cannot occur.
> 
> Ah, exactly. I had to be sleeping when I wrote about deadlock.
> How about the locking order? Do you think d_lock after dcache_lru_lock
> is a problem?

>From fs/dcache.c:

 * Ordering:
 * dentry->d_inode->i_lock
 *   dentry->d_lock
 *     dcache_lru_lock
 *     dcache_hash_bucket lock
 *     s_anon lock

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com
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