Return-Path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:50877 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754784Ab0LAUeF (ORCPT ); Wed, 1 Dec 2010 15:34:05 -0500 Date: Wed, 1 Dec 2010 12:33:41 -0800 From: Andrew Morton To: Trond Myklebust Cc: Linus Torvalds , Nick Bowler , Linux Kernel Mailing List , linux-nfs@vger.kernel.org, Hugh Dickins , Rik van Riel , Christoph Hellwig , Al Viro Subject: Re: [PATCH v2 3/3] NFS: Fix a memory leak in nfs_readdir Message-Id: <20101201123341.d12ef362.akpm@linux-foundation.org> In-Reply-To: <1291234251.6609.39.camel@heimdal.trondhjem.org> References: <1291217804-11257-1-git-send-email-Trond.Myklebust@netapp.com> <1291217804-11257-2-git-send-email-Trond.Myklebust@netapp.com> <20101201150428.GA2879@elliptictech.com> <1291217804-11257-3-git-send-email-Trond.Myklebust@netapp.com> <1291217804-11257-4-git-send-email-Trond.Myklebust@netapp.com> <1291229669.6609.24.camel@heimdal.trondhjem.org> <1291234251.6609.39.camel@heimdal.trondhjem.org> Content-Type: text/plain; charset=US-ASCII Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 On Wed, 01 Dec 2010 15:10:50 -0500 Trond Myklebust wrote: > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -602,6 +602,7 @@ struct address_space_operations { > sector_t (*bmap)(struct address_space *, sector_t); > void (*invalidatepage) (struct page *, unsigned long); > int (*releasepage) (struct page *, gfp_t); > + void (*freepage)(struct page *); > ssize_t (*direct_IO)(int, struct kiocb *, const struct iovec *iov, > loff_t offset, unsigned long nr_segs); > int (*get_xip_mem)(struct address_space *, pgoff_t, int, It would be good to think about and then clearly spell out exactly what state the page is in here. It is locked, and I assume clean and not under writeback. What about its refcount, freezedness status and eligibility for lookups? And as Hugh pointed out, some callees might needs the address_space* although we can perhaps defer that until such a callee turns up. If/when that happens we might have a problem though: if this locked page is no longer attached to the address_space then what now pins the address_space, protecting it from inode reclaim?