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=-0.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 115FCC433DF for ; Wed, 17 Jun 2020 02:22:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DC9242080D for ; Wed, 17 Jun 2020 02:22:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Pw7h6Zur" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726697AbgFQCWE (ORCPT ); Tue, 16 Jun 2020 22:22:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59946 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726253AbgFQCWD (ORCPT ); Tue, 16 Jun 2020 22:22:03 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C4507C061573; Tue, 16 Jun 2020 19:22:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Transfer-Encoding :Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=BEusnUbR+/cmrBB9bk/xdvHCANKyUH/aAcSZAMuW5OE=; b=Pw7h6Zurn3kEfvE1eYLcuqezpS 6dv6YNzk6+f6NL9T5b1t5Q3S1oT5qqAMDEOxHE+1wGzAU1/UvkbHdNz07Ga1WaCWGzhKUCRSeZ6QZ o0I5/jAy2zGLAu1G4S3MZdS3qCqGws/6WiA4NRqQjbA9SmyY+Nnm0QKGoSQJFNIHsS2xUI0I9Udce qOHpLfYIPOR526dlzyvkD4gq0Xo6OO+YQA5h+uvfTaDDzfQbzfntE6t8KKL/bdGZugpf9j96kxyXi uqj9bm92o25yQodA2+9jXT7MN6tTeGOpuEujbqml8NcV0guvi1GGbOd5RpsedFvm4bLu4W95FUUfR YKCs+4uQ==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jlNi9-0002wT-UP; Wed, 17 Jun 2020 02:21:57 +0000 Date: Tue, 16 Jun 2020 19:21:57 -0700 From: Matthew Wilcox To: Andreas =?iso-8859-1?Q?Gr=FCnbacher?= Cc: Andreas Gruenbacher , Andrew Morton , linux-xfs , Junxiao Bi , William Kucharski , Joseph Qi , John Hubbard , LKML , linux-f2fs-devel@lists.sourceforge.net, cluster-devel , Linux-MM , ocfs2-devel@oss.oracle.com, linux-fsdevel , linux-ext4 , linux-erofs@lists.ozlabs.org, Christoph Hellwig , linux-btrfs@vger.kernel.org, Steven Whitehouse , Bob Peterson Subject: Re: [Cluster-devel] [PATCH v11 16/25] fs: Convert mpage_readpages to mpage_readahead Message-ID: <20200617022157.GF8681@bombadil.infradead.org> References: <20200414150233.24495-1-willy@infradead.org> <20200414150233.24495-17-willy@infradead.org> <20200617003216.GC8681@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 17, 2020 at 02:57:14AM +0200, Andreas Grünbacher wrote: > Am Mi., 17. Juni 2020 um 02:33 Uhr schrieb Matthew Wilcox : > > > > On Wed, Jun 17, 2020 at 12:36:13AM +0200, Andreas Gruenbacher wrote: > > > Am Mi., 15. Apr. 2020 um 23:39 Uhr schrieb Matthew Wilcox : > > > > From: "Matthew Wilcox (Oracle)" > > > > > > > > Implement the new readahead aop and convert all callers (block_dev, > > > > exfat, ext2, fat, gfs2, hpfs, isofs, jfs, nilfs2, ocfs2, omfs, qnx6, > > > > reiserfs & udf). The callers are all trivial except for GFS2 & OCFS2. > > > > > > This patch leads to an ABBA deadlock in xfstest generic/095 on gfs2. > > > > > > Our lock hierarchy is such that the inode cluster lock ("inode glock") > > > for an inode needs to be taken before any page locks in that inode's > > > address space. > > > > How does that work for ... > > > > writepage: yes, unlocks (see below) > > readpage: yes, unlocks > > invalidatepage: yes > > releasepage: yes > > freepage: yes > > isolate_page: yes > > migratepage: yes (both) > > putback_page: yes > > launder_page: yes > > is_partially_uptodate: yes > > error_remove_page: yes > > > > Is there a reason that you don't take the glock in the higher level > > ops which are called before readhead gets called? I'm looking at XFS, > > and it takes the xfs_ilock SHARED in xfs_file_buffered_aio_read() > > (called from xfs_file_read_iter). > > Right, the approach from the following thread might fix this: > > https://lore.kernel.org/linux-fsdevel/20191122235324.17245-1-agruenba@redhat.com/T/#t In general, I think this is a sound approach. Specifically, I think FAULT_FLAG_CACHED can go away. map_pages() will bring in the pages which are in the page cache, so when we get to gfs2_fault(), we know there's a reason to acquire the glock.