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=-12.9 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1, USER_IN_DEF_DKIM_WL autolearn=no 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 3EF10C433E2 for ; Thu, 17 Sep 2020 02:05:18 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 956792076C for ; Thu, 17 Sep 2020 02:05:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="SxAIwAWl" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 956792076C Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id C67D4900009; Wed, 16 Sep 2020 22:05:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id BF052900004; Wed, 16 Sep 2020 22:05:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B0516900009; Wed, 16 Sep 2020 22:05:16 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0147.hostedemail.com [216.40.44.147]) by kanga.kvack.org (Postfix) with ESMTP id 9BE20900004 for ; Wed, 16 Sep 2020 22:05:16 -0400 (EDT) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 5388B3624 for ; Thu, 17 Sep 2020 02:05:16 +0000 (UTC) X-FDA: 77270911032.24.week41_46063642711e Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin24.hostedemail.com (Postfix) with ESMTP id 2BA6C1A4A0 for ; Thu, 17 Sep 2020 02:05:16 +0000 (UTC) X-HE-Tag: week41_46063642711e X-Filterd-Recvd-Size: 4838 Received: from mail-oo1-f67.google.com (mail-oo1-f67.google.com [209.85.161.67]) by imf01.hostedemail.com (Postfix) with ESMTP for ; Thu, 17 Sep 2020 02:05:15 +0000 (UTC) Received: by mail-oo1-f67.google.com with SMTP id m25so194566oou.0 for ; Wed, 16 Sep 2020 19:05:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:in-reply-to:message-id:references :user-agent:mime-version; bh=FvBdfI3/8JYEzHDwTJchNGznx9TCTfOWN6nMTk+cWRg=; b=SxAIwAWl1MqxQGVya1/LLGYLyQUf80qPgV3UgTzda0zs4xtGvK+4t42qChTNnUsQp2 iidBl3RcjWjxLEf3TZErhnJNVVQbN7kfMfUmVvIATlXjukaBN+biw4DGFEtwxso0eFH3 U57Zvvxg6m/kE5XelTs1/4GU+7H9JXM071r8m/4ZtDTvnHENVfGtnySAZv4kOHTr0OEO nGgEa2imdIkbWGjE4w2eJKI3i7opSAcSjM4lAf/eWxB03Q2LwB/TXuLJwne9YkNYXg0u /h/dWj2zkQOOZ9HHYhSHhoHJtjkFEXp5gat/GmMoyC4Tw0RZhLUvTdQyQRkgrx/gGf3i dp5A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:in-reply-to:message-id :references:user-agent:mime-version; bh=FvBdfI3/8JYEzHDwTJchNGznx9TCTfOWN6nMTk+cWRg=; b=m0Coa0pfpX7JeE3YcXXqsejMGAotYL+6NU2afXQkWQ3/CLLJ7Drar16y7CFDXp1K5L 2nTmiKpSGcmNEMs4fxV+h0b2r3FgdC1mBNJ8eIJZa4UDo6Ghc8kxKI+h6oLSKrOeeF7Z omt6DVBQkAaiFMVp84useFHvYLSuG7wCP/1x2WJtU1TOVPC5leHiR5q1++OVEffHqQJ2 hEhDi+FXasXvljPgU1aJbD7LEshxINU28EZftXbcILR5ZIdNeYMLvtLZ+p4AXRnZiWUt nsJllhslVarxIhKK1aDMLfIVS+B5gVaefHJlrVOvs+Il7hOje8WVZh4EpwdDS9YoGp0n FzAQ== X-Gm-Message-State: AOAM530eHevIhyqbnIaxyPW/VrkYXPdyJOOItDEZ3d6fKGiz6d8VUkx/ rY18NYrumhv2GhJ1YfBBrDTZ0Q== X-Google-Smtp-Source: ABdhPJwlHAL814Qbgr+EScHD+loUynWF6I3FcBxRyuexwIjAE/FXXv9TKSXjo79ezbsysUHb+aAFHw== X-Received: by 2002:a4a:c541:: with SMTP id j1mr19671594ooq.13.1600308314725; Wed, 16 Sep 2020 19:05:14 -0700 (PDT) Received: from eggly.attlocal.net (172-10-233-147.lightspeed.sntcca.sbcglobal.net. [172.10.233.147]) by smtp.gmail.com with ESMTPSA id a4sm8527275oif.3.2020.09.16.19.05.09 (version=TLS1 cipher=ECDHE-ECDSA-AES128-SHA bits=128/128); Wed, 16 Sep 2020 19:05:11 -0700 (PDT) Date: Wed, 16 Sep 2020 19:04:46 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@eggly.anvils To: Dave Chinner cc: Jan Kara , Amir Goldstein , Andreas Gruenbacher , Theodore Tso , Martin Brandenburg , Mike Marshall , Damien Le Moal , Jaegeuk Kim , Qiuyang Sun , linux-xfs , linux-fsdevel , Linux MM , linux-kernel , Matthew Wilcox , Linus Torvalds , "Kirill A. Shutemov" , Andrew Morton , Al Viro , nborisov@suse.de Subject: Re: More filesystem need this fix (xfs: use MMAPLOCK around filemap_map_pages()) In-Reply-To: <20200917014454.GZ12131@dread.disaster.area> Message-ID: References: <20200623052059.1893966-1-david@fromorbit.com> <20200916155851.GA1572@quack2.suse.cz> <20200917014454.GZ12131@dread.disaster.area> User-Agent: Alpine 2.11 (LSU 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Rspamd-Queue-Id: 2BA6C1A4A0 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 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 Thu, 17 Sep 2020, Dave Chinner wrote: > > So.... > > P0 p1 > > hole punch starts > takes XFS_MMAPLOCK_EXCL > truncate_pagecache_range() > unmap_mapping_range(start, end) > > > do_fault_around() > ->map_pages > filemap_map_pages() > page mapping valid, > page is up to date > maps PTEs > > truncate_inode_pages_range() > truncate_cleanup_page(page) > invalidates page > delete_from_page_cache_batch(page) > frees page > No. filemap_map_pages() checks page->mapping after trylock_page(), before setting up the pte; and truncate_cleanup_page() does a one-page unmap_mapping_range() if page_mapped(), while holding page lock. (Of course, there's a different thread, in which less reliance on page lock is being discussed, but that would be a future thing.) Hugh