tests/btrfs/263

#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2022 SUSE Linux Products GmbH.  All Rights Reserved.
#
# FS QA Test 263
#
# Make sure btrfs autodefrag will not defrag ranges which won't reduce
# defragmentation.
#
. ./common/preamble
_begin_fstest auto quick defrag fiemap remount

. ./common/filter

_require_scratch
_require_xfs_io_command "fiemap" "ranged"

# Needs fixed 4K sector size, or the file layout will not match the expected
# result.
_require_btrfs_support_sectorsize 4096

_scratch_mkfs >> $seqres.full

_scratch_mount -o noautodefrag

# Create the initial layout, with a large 64K extent for later fragments.
$XFS_IO_PROG -f -c "pwrite 0 64K" -c sync "$SCRATCH_MNT/foobar" >> $seqres.full

# Need to bump the generation by one, as autodefrag uses the last modified
# generation of a subvolume. Without this generation bump, autodefrag will
# defrag the whole file, not only the new write.
touch "$SCRATCH_MNT/trash"
sync

# Remount to autodefrag.
_scratch_remount autodefrag

# Write a new sector, which should trigger autodefrag.
$XFS_IO_PROG -c "pwrite 16K 4K" -c sync "$SCRATCH_MNT/foobar" >> $seqres.full

echo "=== File extent layout before autodefrag ===" >> $seqres.full
$XFS_IO_PROG -c "fiemap -v" "$SCRATCH_MNT/foobar" >> $seqres.full

old_csum=$(_md5_checksum "$SCRATCH_MNT/foobar")
old_ext_0=$(_get_file_extent_sector "$SCRATCH_MNT/foobar" 0)
old_ext_16k=$(_get_file_extent_sector "$SCRATCH_MNT/foobar" 16384)
old_ext_20k=$(_get_file_extent_sector "$SCRATCH_MNT/foobar" 20480)

# Trigger autodefrag.
_scratch_remount commit=1
sleep 3
# Make sure the defragged range reach disk.
sync

echo "=== File extent layout after autodefrag ===" >> $seqres.full
$XFS_IO_PROG -c "fiemap -v" "$SCRATCH_MNT/foobar" >> $seqres.full

new_csum=$(_md5_checksum "$SCRATCH_MNT/foobar")
new_ext_0=$(_get_file_extent_sector "$SCRATCH_MNT/foobar" 0)
new_ext_16k=$(_get_file_extent_sector "$SCRATCH_MNT/foobar" 16384)
new_ext_20k=$(_get_file_extent_sector "$SCRATCH_MNT/foobar" 20480)

# For extent at offset 0 and 20K, they are older than the target generation,
# thus they should not be defragged.
if [ "$new_ext_0" != "$old_ext_0" ]; then
	echo "extent at offset 0 got defragged"
fi
if [ "$new_ext_20k" != "$old_ext_20k" ]; then
	echo "extent at offset 20K got defragged"
fi

# For extent at offset 4K, it's a single sector, and its adjacent extents
# are not targets, thus it should not be defragged.
if [ "$new_ext_16k" != "$old_ext_16k" ]; then
	echo "extent at offset 16K got defragged"
fi

# Defrag should not change file content.
if [ "$new_csum" != "$old_csum" ]; then
	echo "file content changed"
fi

echo "Silence is golden"

# success, all done
status=0
exit