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From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Wed, 1 Dec 2010 12:18:58 -0800
Message-ID: <AANLkTi=Spd1OvdijN7kEJBBdYdTRuVnwPUqZvAUUiaKF@mail.gmail.com>
Subject: Re: [PATCH v2 3/3] NFS: Fix a memory leak in nfs_readdir
To: Trond Myklebust <Trond.Myklebust@netapp.com>
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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On Wed, Dec 1, 2010 at 12:10 PM, Trond Myklebust
<Trond.Myklebust@netapp.com> wrote:
>
> Something like the following then?
> diff --git a/mm/truncate.c b/mm/truncate.c
> index ba887bf..76ab2a8 100644
> --- a/mm/truncate.c
> +++ b/mm/truncate.c
> @@ -108,6 +108,10 @@ truncate_complete_page(struct address_space *mapping, struct page *page)
> ? ? ? ?clear_page_mlock(page);
> ? ? ? ?remove_from_page_cache(page);
> ? ? ? ?ClearPageMappedToDisk(page);
> +
> + ? ? ? if (mapping->a_ops->freepage)
> + ? ? ? ? ? ? ? mapping->a_ops->freepage(page);
> +
> ? ? ? ?page_cache_release(page); ? ? ? /* pagecache ref */
> ? ? ? ?return 0;
> ?}

I'd do this in "remove_from_page_cache()" instead of in
"truncate_complete_page()". Otherwise it will miss any other callers
that use "remove_from_page_cache()" (not that there are many, and I
doubt NFS cares about the ones that do exists, but..)

                 Linus