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=-16.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 7DC94C433FE for ; Mon, 13 Sep 2021 17:37:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 68764610CE for ; Mon, 13 Sep 2021 17:37:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243554AbhIMRiq (ORCPT ); Mon, 13 Sep 2021 13:38:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:41386 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243543AbhIMRio (ORCPT ); Mon, 13 Sep 2021 13:38:44 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 629F6603E7; Mon, 13 Sep 2021 17:37:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1631554648; bh=4QJS2bzb/cEKhpK6hvRXStqgnRg9u6La0KitZwoTsZo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=gK7NpjtLD67wMcKQi7VBmxS3Ks8xDbNspNbjC+tq1Q0CVv1+n82oKCSQSNb957tIC 8QMX2jNH+xI7qCEvc1gBMBlNB+BIKV+/2A79ptty83Upp0eyYP2W7HIclng9mJww2l PY21t1OUaGrW5HpJ/5unNZHt/e2ez8GRM9daD9858i03c4dp2bSGykKa5BuIiWHxqb v7r/phEvvVxJK05GamCtArHk9x7HQTW73yat6nt5nWPgiM36GOTYhy9sPenR36JZBn 117cCrokg23XqQ4F1Ez/QOsFaj1JZj9vS3jSLU4rE58XwHHQCtAtxQoArc0w+gmxAA W1QUHGBNjVnZw== Date: Mon, 13 Sep 2021 10:37:28 -0700 From: "Darrick J. Wong" To: Eryu Guan Cc: guaneryu@gmail.com, linux-xfs@vger.kernel.org, fstests@vger.kernel.org Subject: Re: [PATCH 1/3] xfs: test fsx with extent size hints set on a realtime file Message-ID: <20210913173728.GB638503@magnolia> References: <163045508495.769915.4859353445119566326.stgit@magnolia> <163045509043.769915.12768254084054792591.stgit@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Sun, Sep 05, 2021 at 10:28:16PM +0800, Eryu Guan wrote: > On Tue, Aug 31, 2021 at 05:11:30PM -0700, Darrick J. Wong wrote: > > From: Darrick J. Wong > > > > This is a regression test for the two realtime allocator bug fixes: > > > > xfs: adjust rt allocation minlen when extszhint > rtextsize > > xfs: retry allocations when locality-based search fails > > > > Signed-off-by: Darrick J. Wong > > Looks fine to me, just a few minor nits inline. > > > --- > > tests/xfs/775 | 165 +++++++++++++++++++++++++++++++++++++++++++++++++++++ > > tests/xfs/775.out | 3 + > > 2 files changed, 168 insertions(+) > > create mode 100755 tests/xfs/775 > > create mode 100644 tests/xfs/775.out > > > > > > diff --git a/tests/xfs/775 b/tests/xfs/775 > > new file mode 100755 > > index 00000000..e8e6b728 > > --- /dev/null > > +++ b/tests/xfs/775 > > @@ -0,0 +1,165 @@ > > +#! /bin/bash > > +# SPDX-License-Identifier: GPL-2.0 > > +# Copyright (c) 2021, Oracle. All Rights Reserved. > > +# > > +# FS QA Test No. 775 > > +# > > +# Regression test for commits: > > +# > > +# 9d5e8492eee0 ("xfs: adjust rt allocation minlen when extszhint > rtextsize") > > +# 676a659b60af ("xfs: retry allocations when locality-based search fails") > > +# > > +# The first bug occurs when an extent size hint is set on a realtime file. > > +# xfs_bmapi_rtalloc adjusts the offset and length of the allocation request to > > +# try to satisfy the hint, but doesn't adjust minlen to match. If the > > +# allocator finds free space that isn't large enough to map even a single block > > +# of the original request, bmapi_write will return ENOSPC and the write fails > > +# even though there's plenty of space. > > +# > > +# The second bug occurs when an extent size hint is set on a file, we ask to > > +# allocate blocks in an empty region immediately adjacent to a previous > > +# allocation, and the nearest available free space isn't anywhere near the > > +# previous allocation, the near allocator will give up and return ENOSPC, even > > +# if there's sufficient free realtime extents to satisfy the allocation > > +# request. > > +# > > +# Both bugs can be exploited by the same user call sequence, so here's a > > +# targeted test that runs in less time than the reproducers that are listed in > > +# the fix patches themselves. > > +# > > +. ./common/preamble > > +_begin_fstest auto quick rw realtime > > + > > +# Override the default cleanup function. > > +_cleanup() > > +{ > > + cd / > > +} > > Seems there's no need to override the default cleanup function? Yeah. I'll clobber it. > > + > > +# Import common functions. > > +. ./common/filter > > + > > +# real QA test starts here > > _supported_fs xfs Fixed. > > +_require_scratch > > +_require_realtime > > +_require_xfs_io_command "falloc" > > +_require_xfs_io_command "fpunch" > > +_require_test_program "punch-alternating" > > + > > +fill_rtdev() > > +{ > > + file=$1 > > + > > + filesize=`_get_available_space $SCRATCH_MNT` > > + $XFS_IO_PROG -f -c "truncate $filesize" -c "falloc 0 $filesize" $file > > + > > + chunks=20 > > + chunksizemb=$((filesize / chunks / 1048576)) > > + seq 1 $chunks | while read f; do > > + echo "$((f * chunksizemb)) file size $f / 20" > > + $XFS_IO_PROG -fc "falloc -k $(( (f - 1) * chunksizemb))m ${chunksizemb}m" $file > > + done > > + > > + chunks=100 > > + chunksizemb=$((filesize / chunks / 1048576)) > > + seq 80 $chunks | while read f; do > > + echo "$((f * chunksizemb)) file size $f / $chunks" > > + $XFS_IO_PROG -fc "falloc -k $(( (f - 1) * chunksizemb))m ${chunksizemb}m" $file > > + done > > + > > + filesizemb=$((filesize / 1048576)) > > + $XFS_IO_PROG -fc "falloc -k 0 ${filesizemb}m" $file > > + > > + # Try again anyway > > + avail=`_get_available_space $SCRATCH_MNT` > > + $XFS_IO_PROG -fc "pwrite -S 0x65 0 $avail" ${file} > > +} > > + > > +echo "Format and mount" > > +_scratch_mkfs > $seqres.full 2>&1 > > +_scratch_mount >> $seqres.full 2>&1 > > + > > +# This is a test of the rt allocator; force all files to be created realtime > > +_xfs_force_bdev realtime $SCRATCH_MNT > > + > > +# Set the extent size hint larger than the realtime extent size. This is > > +# necessary to exercise the minlen constraints on the realtime allocator. > > +fsbsize=$($XFS_IO_PROG -c 'statfs' $SCRATCH_MNT | grep geom.bsize | awk '{print $3}') > > +rtextsize_blks=$($XFS_IO_PROG -c 'statfs' $SCRATCH_MNT | grep geom.rtextsize | awk '{print $3}') > > +extsize=$((2 * rtextsize_blks * fsbsize)) > > + > > +echo "rtextsize_blks=$rtextsize_blks extsize=$extsize" >> $seqres.full > > +_xfs_force_bdev realtime $SCRATCH_MNT > > Already done above, could be removed? Yup, fixed. --D > Thanks, > Eryu > > > +$XFS_IO_PROG -c "extsize $extsize" $SCRATCH_MNT > > + > > +# Compute the geometry of the test files we're going to create. Realtime > > +# volumes are simple, which means that we can control the space allocations > > +# exactly to exploit bugs! > > +# > > +# Since this is a test of the near rt allocator, we need to set up the test to > > +# have a victim file with at least one rt extent allocated to it and enough > > +# free space to allocate at least one more rt extent at an adjacent file > > +# offset. The free space must not be immediately adjacent to the the first > > +# extent that we allocate to the victim file, and it must not be large enough > > +# to satisfy the entire allocation request all at once. > > +# > > +# Our free space fragmentation strategy is the usual fallocate-and-punch swiss > > +# cheese file, which means the free space is split into five sections: > > +# > > +# The first will be remapped into the victim file. > > +# > > +# The second section exists to prevent the free extents from being adjacent to > > +# the first section. It will be very large, since we allocate all the rt > > +# space. > > +# > > +# The last three sections will have every other rt extent punched out to create > > +# some free space. > > +remap_sz=$((extsize * 2)) > > +required_sz=$((5 * remap_sz)) > > +free_rtspace=$(_get_available_space $SCRATCH_MNT) > > +if [ $free_rtspace -lt $required_sz ]; then > > + _notrun "Insufficient free space on rt volume. Needed $required_sz, saw $free_rtspace." > > +fi > > + > > +# Allocate all the space on the rt volume so that we can control space > > +# allocations exactly. > > +fill_rtdev $SCRATCH_MNT/bigfile &>> $seqres.full > > + > > +# We need at least 4 remap sections to proceed > > +bigfile_sz=$(stat -c '%s' $SCRATCH_MNT/bigfile) > > +if [ $bigfile_sz -lt $required_sz ]; then > > + _notrun "Free space control file needed $required_sz bytes, got $bigfile_sz." > > +fi > > + > > +# Remap the first remap section to a victim file. > > +$XFS_IO_PROG -c "fpunch 0 $remap_sz" $SCRATCH_MNT/bigfile > > +$XFS_IO_PROG -f -c "truncate $required_sz" -c "falloc 0 $remap_sz" $SCRATCH_MNT/victim > > + > > +# Punch out every other extent of the last two sections, to fragment free space. > > +frag_sz=$((remap_sz * 3)) > > +punch_off=$((bigfile_sz - frag_sz)) > > +$here/src/punch-alternating $SCRATCH_MNT/bigfile -o $((punch_off / fsbsize)) -i $((rtextsize_blks * 2)) -s $rtextsize_blks > > + > > +# Make sure we have some free rtextents. > > +free_rtx=$($XFS_IO_PROG -c 'statfs' $SCRATCH_MNT | grep counts.freertx | awk '{print $3}') > > +if [ $free_rtx -eq 0 ]; then > > + echo "Expected fragmented free rt space, found none." > > +fi > > + > > +# Try to double the amount of blocks in the victim file. On a buggy kernel, > > +# the rt allocator will fail immediately with ENOSPC even though we left enough > > +# free space for the write will complete fully. > > +echo "Try to write a bunch of stuff to the fragmented rt space" > > +$XFS_IO_PROG -c "pwrite -S 0x63 -b $remap_sz $remap_sz $remap_sz" -c stat $SCRATCH_MNT/victim >> $seqres.full > > + > > +# The victim file should own at least two sections' worth of blocks. > > +victim_sectors=$(stat -c '%b' $SCRATCH_MNT/victim) > > +victim_space_usage=$((victim_sectors * 512)) > > +expected_usage=$((remap_sz * 2)) > > + > > +if [ $victim_space_usage -lt $expected_usage ]; then > > + echo "Victim file should be using at least $expected_usage bytes, saw $victim_space_usage." > > +fi > > + > > +status=0 > > +exit > > diff --git a/tests/xfs/775.out b/tests/xfs/775.out > > new file mode 100644 > > index 00000000..f5a72156 > > --- /dev/null > > +++ b/tests/xfs/775.out > > @@ -0,0 +1,3 @@ > > +QA output created by 775 > > +Format and mount > > +Try to write a bunch of stuff to the fragmented rt space