From patchwork Tue Jul 20 01:08:36 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Darrick J. Wong" X-Patchwork-Id: 12387187 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=-17.5 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=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 AAF65C07E9B for ; Tue, 20 Jul 2021 01:13:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9AD9261004 for ; Tue, 20 Jul 2021 01:13:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348752AbhGTAcT (ORCPT ); Mon, 19 Jul 2021 20:32:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:41610 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1381031AbhGTA15 (ORCPT ); Mon, 19 Jul 2021 20:27:57 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 795C860FF3; Tue, 20 Jul 2021 01:08:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1626743316; bh=1Ye9+Itf7W9gAZBRh6ivtNyhZsWEi5+BWWPGG8bKghY=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=fCZMgbX+QaXNccDqaOQ6+NnKoUKtSMFM9J3EhMG5hpQerjaR+qAjucEnLj4J4e6or q5ChGkgVMUOfGf5THUP9qwvuDyxLXOETpAsg+6KCkQ9I/369eol6cyNddODWyJIC/A Rt0AiI9xGWXc9aWb/ckYNC8xDHTJJjDSo+dyv00jwXUhFBsV+uR6Y+za4tEywtSoeE dE6rOqJwOyiLAZHy5ASGP4N4Gumbws3zkNkuXoemlY2JleC0QNQbXt7+/mwP/5yOIl /EPMWNxjPMSeWAGJVnmUSrAfLMGXOk34qKvp17c7BlroylIU+nRGTqSuDLvoJ55tKq QstAABIIi3eaw== Subject: [PATCH 1/2] xfs: test fsx with extent size hints set on a realtime file From: "Darrick J. Wong" To: djwong@kernel.org, guaneryu@gmail.com Cc: linux-xfs@vger.kernel.org, fstests@vger.kernel.org, guan@eryu.me Date: Mon, 19 Jul 2021 18:08:36 -0700 Message-ID: <162674331623.2650812.5383791641373151272.stgit@magnolia> In-Reply-To: <162674331075.2650812.11935724515971931345.stgit@magnolia> References: <162674331075.2650812.11935724515971931345.stgit@magnolia> User-Agent: StGit/0.19 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: fstests@vger.kernel.org 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 --- 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..e6a4c28b --- /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 two fixes in the realtime allocator: +# +# xfs: adjust rt allocation minlen when extszhint > rtextsize +# 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 / +} + +# Import common functions. +. ./common/filter + +# real QA test starts here +_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 $SCRATCH_MNT +$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