Subject: Re: [PATCH v2 3/3] NFS: Fix a memory leak in nfs_readdir
From: Trond Myklebust <Trond.Myklebust@netapp.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nick Bowler <nbowler@elliptictech.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-nfs@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>,
        Hugh Dickins <hughd@google.com>, Rik van Riel <riel@redhat.com>,
        Christoph Hellwig <hch@lst.de>, Al Viro <viro@zeniv.linux.org.uk>
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Date: Wed, 01 Dec 2010 15:10:50 -0500
Message-ID: <1291234251.6609.39.camel@heimdal.trondhjem.org>
Sender: linux-nfs-owner@vger.kernel.org
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On Wed, 2010-12-01 at 11:47 -0800, Linus Torvalds wrote:
> On Wed, Dec 1, 2010 at 10:54 AM, Trond Myklebust
> <Trond.Myklebust@netapp.com> wrote:
> >
> > Hmm... Looking again at the problem, it appears that the same callback
> > needs to be added to truncate_complete_page() and
> > invalidate_complete_page2(). Otherwise we end up in a situation where
> > the page can sometimes be removed from the page cache without calling
> > freepage().
> 
> Yes, I think any caller of __remove_from_page_cache() should do it
> once it has dropped all locks.
> 
> And to be consistent with that rule, even in the __remove_mapping()
> function I suspect the code to call ->freepage() might as well be done
> only in the __remove_from_page_cache() case (ie not in the
> PageSwapCache() case).
> 
> Then, add the case to the end of "remove_page_cache()" itself, and now
> it's really easy to just grep for __remove_from_page_cache() and make
> sure they all do it.
> 
> That sounds sane, no?
> 
>                 Linus

Something like the following then?

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