From mboxrd@z Thu Jan  1 00:00:00 1970
From: Al Viro <viro@ZenIV.linux.org.uk>
Subject: Re: dcache shrink list corruption?
Date: Tue, 29 Apr 2014 19:16:10 +0100
Message-ID: <20140429181610.GJ18016@ZenIV.linux.org.uk>
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Cc: Linus Torvalds <torvalds@linux-foundation.org>,
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	linux-fsdevel <linux-fsdevel@vger.kernel.org>
To: Miklos Szeredi <miklos@szeredi.hu>
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On Tue, Apr 29, 2014 at 08:03:24PM +0200, Miklos Szeredi wrote:

> Introducing a new per-sb lock should be OK.
> 
> Another idea, which could have subtler effects, is simply not to kill
> a dentry that is on the shrink list (indicated by
> DCACHE_SHRINK_LIST), since it's bound to get killed anyway.  But
> that's a change in behaviour...

Umm...  You mean, if final dput() finds dentry already on shrink list,
just leave it there and return?  Might get really painful - the code
that knows it's holding the last reference to already unhashed dentry
might get a nasty surprise when dput() returns before it's killed off.