From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8BC41C74A35 for ; Wed, 10 Jul 2019 17:51:36 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4FD32208E4 for ; Wed, 10 Jul 2019 17:51:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=cmpxchg-org.20150623.gappssmtp.com header.i=@cmpxchg-org.20150623.gappssmtp.com header.b="UZK6Vmsl" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4FD32208E4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=cmpxchg.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id DBD168E0080; Wed, 10 Jul 2019 13:51:35 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D6D7A8E0032; Wed, 10 Jul 2019 13:51:35 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C5C3E8E0080; Wed, 10 Jul 2019 13:51:35 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-pf1-f198.google.com (mail-pf1-f198.google.com [209.85.210.198]) by kanga.kvack.org (Postfix) with ESMTP id 9095E8E0032 for ; Wed, 10 Jul 2019 13:51:35 -0400 (EDT) Received: by mail-pf1-f198.google.com with SMTP id 21so1769726pfu.9 for ; Wed, 10 Jul 2019 10:51:35 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:date:from:to:cc:subject :message-id:references:mime-version:content-disposition:in-reply-to :user-agent; bh=uKVGZA2rdeScy3bwyoxpCnlfJ0pW69jxWknu9B37i2E=; b=KcHsVyjQwtcTsc7yowJi36DmA3T3dGcqEpwiwksMrPmRcr68FOJjBYhYPt8eaEyorU rh9djSx7mg/NakIgF/3AslGNh/zdzPdjaCmLvzAGlrK/nVvkrmGBhMtURCEQjIVho0p9 quu9fKfoHykj8ZGpdzx9w5gI20L39Ssj3mGddw/UYzQROl1e4F8QzHdhgWaxWYlrRTeJ qpeACbtT0aJKaFfaMoUCXpY2z7b25q9sexgcc6eg5lRB8/8BAC5WLcS8Yu63yGQxZvEZ T5ts79AwB7phlYj553xcLaUjKjeLB+KUn8VK5Vaxd7XrBTXZ85Sv7HgQb+sj3F+8ixBb 1uVw== X-Gm-Message-State: APjAAAUwbwRqn35ToReJ5ks6GmNJgm8jLkM3ziI2Ni34Rxxi2FqA4ehs ycO+7UO2LG8sysOmQJY9FGRCVFb5JSBKjzv1QtMvmj7UfBwpjH8spQeYbWx1VdhiqpqqWuzDYl4 wPZZgT1MWDtRyGxlyOQDbiCIZGg1apDROvK0OLdzTdzZhcuLtJYRhP7LKFZXYqNZLCg== X-Received: by 2002:a65:63cd:: with SMTP id n13mr38391381pgv.153.1562781095218; Wed, 10 Jul 2019 10:51:35 -0700 (PDT) X-Received: by 2002:a65:63cd:: with SMTP id n13mr38391350pgv.153.1562781094539; Wed, 10 Jul 2019 10:51:34 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1562781094; cv=none; d=google.com; s=arc-20160816; b=mK27mPziTkv2N83ceqj/Fqjo9do2SIwe5UeKIz3X/Gv9UlIwiR8048+JtBKooq6g5M 5iXdCj8+tQKNSLZqlFDHwmCou4Kebt6if2SsY7cFIsI4XUiw+1EMgRLOn61hvTz3gnt9 IY0zUqeKztYkcKUU4xzcXiVWeFnbf8zrMdujww+dgAo2uWXxA/HbQQyWR+YP60ADCHLh 6buBxZeUzgbcd/cTtUmcasHBcepF/JA3q027e/2Ptm84Ydp82Hjnl7KxsQ67BCyQXvO4 0aJ9g9zJxZcLRexRmbkFckM+7LFfnUuqpgIDC8Q23OzfnL+zs4GREv8LcvgA8W8aHdcY z+xw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:dkim-signature; bh=uKVGZA2rdeScy3bwyoxpCnlfJ0pW69jxWknu9B37i2E=; b=KqTIdu1KJYeIl9XO9bZS37MRJAvlqmVK2xx2p6aeG0MsFIIWR6H71xp7UK7Dn6I0xe L7ECSdnsADkBbhwEyrgvN2dimR050NVOKGdP039dYBSbtacyf6LODqlgmpvii6KhULFG TabyOavuuOZw6C5iKBLcbrUz47+HWyRVHOz5axnMRAeFOX1Pj4xUtqxx8J3xTgwmSpDn QU4CZOqWU2Yl+xSTdVFcZ3mmGbhkm/lhgrXDcVD+EuVod9TriBKE0xizbSVo1kwnYwmy nbYsQQhQEhkKlOOddcqH8FiX80Wz5zlFMoRdfdc28YShAWOtumxrkJpc5wwcqZ373rIf ox5A== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@cmpxchg-org.20150623.gappssmtp.com header.s=20150623 header.b=UZK6Vmsl; spf=pass (google.com: domain of hannes@cmpxchg.org designates 209.85.220.65 as permitted sender) smtp.mailfrom=hannes@cmpxchg.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=cmpxchg.org Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id s7sor3598333plq.42.2019.07.10.10.51.33 for (Google Transport Security); Wed, 10 Jul 2019 10:51:34 -0700 (PDT) Received-SPF: pass (google.com: domain of hannes@cmpxchg.org designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@cmpxchg-org.20150623.gappssmtp.com header.s=20150623 header.b=UZK6Vmsl; spf=pass (google.com: domain of hannes@cmpxchg.org designates 209.85.220.65 as permitted sender) smtp.mailfrom=hannes@cmpxchg.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=cmpxchg.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cmpxchg-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=uKVGZA2rdeScy3bwyoxpCnlfJ0pW69jxWknu9B37i2E=; b=UZK6Vmsl0GscAoMkvtUuBih99iOojK11B4bvX2Y3xO14yXORhC/0bcYZdxrAsSPYm0 3cghVrqwrNceZtWVPS2OmuOTg8jqhlsmP74StkkSqNt3ZRtstSVQ2rqC4oa52GhxYWYP szwnVtXKZPWmkwhy+poSNKK7HVBlvyd6PMe0AaVqrSmXPBtUAl6kBVIteBLTp/hzC6Ca k1HlOYguhdbAY0QSGQauUptYzwBBp44xNU1GSIkDnJl7S8EffJ29kXDie/6fcE2Xx+9R LzD9VvJHiopZz0iXo4NPCaCU19GtW2sXRJBRyMMl3LJh1svVA5UnfRFEThRroQv5H/BN 8IaA== X-Google-Smtp-Source: APXvYqxf3k6wj0r1DWMxtICEKSsf7cXHz1s9bD0kZqyeu5LkX+cE8uIy0dD31APMZFjW0w+y3Coc3A== X-Received: by 2002:a17:902:1486:: with SMTP id k6mr39639657pla.177.1562781093710; Wed, 10 Jul 2019 10:51:33 -0700 (PDT) Received: from localhost ([2620:10d:c091:500::2:5b9d]) by smtp.gmail.com with ESMTPSA id j15sm2877546pfr.146.2019.07.10.10.51.32 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Wed, 10 Jul 2019 10:51:32 -0700 (PDT) Date: Wed, 10 Jul 2019 13:51:31 -0400 From: Johannes Weiner To: Song Liu Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, matthew.wilcox@oracle.com, kirill.shutemov@linux.intel.com, kernel-team@fb.com, william.kucharski@oracle.com, akpm@linux-foundation.org, hdanton@sina.com Subject: Re: [PATCH v9 1/6] filemap: check compound_head(page)->mapping in filemap_fault() Message-ID: <20190710175131.GB11197@cmpxchg.org> References: <20190625001246.685563-1-songliubraving@fb.com> <20190625001246.685563-2-songliubraving@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190625001246.685563-2-songliubraving@fb.com> User-Agent: Mutt/1.12.0 (2019-05-25) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Jun 24, 2019 at 05:12:41PM -0700, Song Liu wrote: > Currently, filemap_fault() avoids trace condition with truncate by > checking page->mapping == mapping. This does not work for compound > pages. This patch let it check compound_head(page)->mapping instead. > > Acked-by: Rik van Riel > Signed-off-by: Song Liu > --- > mm/filemap.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/filemap.c b/mm/filemap.c > index df2006ba0cfa..f5b79a43946d 100644 > --- a/mm/filemap.c > +++ b/mm/filemap.c > @@ -2517,7 +2517,7 @@ vm_fault_t filemap_fault(struct vm_fault *vmf) > goto out_retry; > > /* Did it get truncated? */ > - if (unlikely(page->mapping != mapping)) { > + if (unlikely(compound_head(page)->mapping != mapping)) { There is another check like these in pagecache_get_page(), which is used by find_lock_page() and thus the truncate code (partial page truncate calls, but this could happen against read-only cache).