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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=ham 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 29B04C282E1 for ; Sat, 25 May 2019 03:32:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EBDA32075C for ; Sat, 25 May 2019 03:32:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726605AbfEYDcs (ORCPT ); Fri, 24 May 2019 23:32:48 -0400 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:49913 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726587AbfEYDcs (ORCPT ); Fri, 24 May 2019 23:32:48 -0400 Received: from callcc.thunk.org ([66.31.38.53]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id x4P3WZG5017423 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 24 May 2019 23:32:36 -0400 Received: by callcc.thunk.org (Postfix, from userid 15806) id 4115D420481; Fri, 24 May 2019 23:32:35 -0400 (EDT) Date: Fri, 24 May 2019 23:32:35 -0400 From: "Theodore Ts'o" To: Jan Kara Cc: linux-ext4@vger.kernel.org, Ira Weiny Subject: Re: [PATCH 3/3] ext4: Gracefully handle ext4_break_layouts() failure during truncate Message-ID: <20190525033235.GB4225@mit.edu> References: <20190522090317.28716-1-jack@suse.cz> <20190522090317.28716-4-jack@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190522090317.28716-4-jack@suse.cz> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Wed, May 22, 2019 at 11:03:17AM +0200, Jan Kara wrote: > ext4_break_layouts() may fail e.g. due to a signal being delivered. > Thus we need to handle its failure gracefully and not by taking the > filesystem down. Currently ext4_break_layouts() failure is rare but it > may become more common once RDMA uses layout leases for handling > long-term page pins for DAX mappings. > > To handle the failure we need to move ext4_break_layouts() earlier > during setattr handling before we do hard to undo changes such as > modifying inode size. To be able to do that we also have to move some > other checks which are better done without holding i_mmap_sem earlier. > > Reported-and-tested-by: Ira Weiny > Reviewed-by: Ira Weiny > Signed-off-by: Jan Kara When doing some final testing before sending a pull request to Linus, I found a regression. After bisecting, this patch fails reliably under gce-xfstests: TESTRUNID: tytso-20190524230226 KERNEL: kernel 5.1.0-rc3-xfstests-00039-g079f9927c7bf #1016 SMP Fri May 24 23:00:47 EDT 2019 x86_64 CMDLINE: -c 4k generic/092 CPUS: 2 MEM: 7680 ext4/4k: 1 tests, 1 failures, 2 seconds generic/092 Failed 1s Totals: 1 tests, 0 skipped, 1 failures, 0 errors, 1s FSTESTPRJ: gce-xfstests FSTESTVER: fio fio-3.2 (Fri, 3 Nov 2017 15:23:49 -0600) FSTESTVER: quota 62661bd (Tue, 2 Apr 2019 17:04:37 +0200) FSTESTVER: xfsprogs v5.0.0 (Fri, 3 May 2019 12:14:36 -0500) FSTESTVER: xfstests-bld 9582562 (Sun, 12 May 2019 00:38:51 -0400) FSTESTVER: xfstests linux-v3.8-2390-g64233614 (Thu, 16 May 2019 00:12:52 -0400) FSTESTCFG: 4k FSTESTSET: generic/092 FSTESTOPT: aex GCE ID: 343197219467628221 generic/092 0s ... [23:05:07] [23:05:08]- output mismatch (see /results/ext4/results-4k/generic/092 .out.bad) % diff -u /tmp/results-tytso-20190524230226/ext4/results-4k/generic/092.out.bad /usr/projects/xfstests-bld/build-64/xfstests-dev/tests/generic/092.out --- /tmp/results-tytso-20190524230226/ext4/results-4k/generic/092.out.bad 2019-05-24 23:05:08.000000000 -0400 +++ /usr/projects/xfstests-bld/build-64/xfstests-dev/tests/generic/092.out 2018-02-13 23:37:20.330097382 -0500 @@ -2,6 +2,5 @@ wrote 5242880/5242880 bytes at offset 0 XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) 0: [0..10239]: data -1: [10240..20479]: unwritten 0: [0..10239]: data 1: [10240..20479]: unwritten Dropping this patch makes the test failure go away. So I'm going to drop it for now. Jan, can you take a look? Thanks!! - Ted