From bf49b2cde6d6a25d9174006bd7d443601fd97575 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Fri, 28 Jan 2022 08:27:01 +0800 Subject: [PATCH] btrfs: defrag with compressed extents There is a long existing bug in btrfs defrag code that it will always try to defrag compressed extents, even they are already at max capacity. This will not reduce the number of extents, but only waste IO/CPU. The kernel fix is titled: btrfs: defrag: don't defrag extents which is already at its max capacity Signed-off-by: Qu Wenruo Reviewed-by: Filipe Manana Signed-off-by: Eryu Guan --- tests/btrfs/259 | 57 +++++++++++++++++++++++++++++++++++++++++++++ tests/btrfs/259.out | 2 ++ 2 files changed, 59 insertions(+) create mode 100755 tests/btrfs/259 create mode 100644 tests/btrfs/259.out diff --git a/tests/btrfs/259 b/tests/btrfs/259 new file mode 100755 index 00000000..e7bd8ddd --- /dev/null +++ b/tests/btrfs/259 @@ -0,0 +1,57 @@ +#! /bin/bash +# SPDX-License-Identifier: GPL-2.0 +# Copyright (C) 2022 SUSE Linux Products GmbH. All Rights Reserved. +# +# FS QA Test 259 +# +# Make sure btrfs defrag ioctl won't defrag compressed extents which are already +# at their max capacity. +# +. ./common/preamble +_begin_fstest auto quick defrag + +# Import common functions. +. ./common/filter +. ./common/btrfs + +# real QA test starts here + +# Modify as appropriate. +_supported_fs btrfs +_require_scratch + +_scratch_mkfs >> $seqres.full + +_scratch_mount -o compress + +# Btrfs uses 128K as max extent size for compressed extents, this would result +# several compressed extents all at their max size +$XFS_IO_PROG -f -c "pwrite -S 0xee 0 16m" -c sync \ + $SCRATCH_MNT/foobar >> $seqres.full + +old_csum=$(_md5_checksum $SCRATCH_MNT/foobar) + +echo "=== File extent layout before defrag ===" >> $seqres.full +$XFS_IO_PROG -c "fiemap -v" "$SCRATCH_MNT/foobar" >> $seqres.full +$XFS_IO_PROG -c "fiemap -v" "$SCRATCH_MNT/foobar" > $tmp.before + +$BTRFS_UTIL_PROG filesystem defrag "$SCRATCH_MNT/foobar" >> $seqres.full +sync + +new_csum=$(_md5_checksum $SCRATCH_MNT/foobar) + +echo "=== File extent layout before defrag ===" >> $seqres.full +$XFS_IO_PROG -c "fiemap -v" "$SCRATCH_MNT/foobar" >> $seqres.full +$XFS_IO_PROG -c "fiemap -v" "$SCRATCH_MNT/foobar" > $tmp.after + +if [ $new_csum != $old_csum ]; then + echo "file content changed" +fi + +diff -q $tmp.before $tmp.after || echo "compressed extents get defragged" + +echo "Silence is golden" + +# success, all done +status=0 +exit diff --git a/tests/btrfs/259.out b/tests/btrfs/259.out new file mode 100644 index 00000000..bfbd2dea --- /dev/null +++ b/tests/btrfs/259.out @@ -0,0 +1,2 @@ +QA output created by 259 +Silence is golden -- 2.39.5