tests/btrfs/258

#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (C) 2022 SUSE Linux Products GmbH. All Rights Reserved.
#
# FS QA Test 258
#
# Make sure btrfs auto defrag can properly defrag clusters which has hole
# in the middle
#
. ./common/preamble
_begin_fstest auto defrag quick fiemap remount

. ./common/filter

_require_scratch
_require_xfs_io_command "fiemap"

# Needs 4K sectorsize, as larger sectorsize can change the file layout.
_require_btrfs_support_sectorsize 4096

_scratch_mkfs >> $seqres.full

# Need datacow to show which range is defragged, and we're testing
# autodefrag
_scratch_mount -o datacow,autodefrag

# Create a layout where we have fragmented extents at [0, 64k) (sync write in
# reserve order), then a hole at [64k, 128k)
$XFS_IO_PROG -f -s -c "pwrite 48k 16k" -c "pwrite 32k 16k" \
		-c "pwrite 16k 16k" -c "pwrite 0 16k" \
		$SCRATCH_MNT/foobar >> $seqres.full
truncate -s 128k $SCRATCH_MNT/foobar

old_csum=$(_md5_checksum $SCRATCH_MNT/foobar)
echo "=== File extent layout before autodefrag ===" >> $seqres.full
$XFS_IO_PROG -c "fiemap -v" "$SCRATCH_MNT/foobar" >> $seqres.full
echo "old md5=$old_csum" >> $seqres.full

old_regular=$(_get_file_extent_sector "$SCRATCH_MNT/foobar" 0)
old_hole=$(_get_file_extent_sector "$SCRATCH_MNT/foobar" 64k)

# Now trigger autodefrag, autodefrag is triggered in the cleaner thread,
# which will be woken up by commit thread
_scratch_remount commit=1
sleep 3
sync

new_csum=$(_md5_checksum $SCRATCH_MNT/foobar)
new_regular=$(_get_file_extent_sector "$SCRATCH_MNT/foobar" 0)
new_hole=$(_get_file_extent_sector "$SCRATCH_MNT/foobar" 64k)

echo "=== File extent layout after autodefrag ===" >> $seqres.full
$XFS_IO_PROG -c "fiemap -v" "$SCRATCH_MNT/foobar" >> $seqres.full
echo "new md5=$new_csum" >> $seqres.full

# In v5.11~v5.15 kernels, regular extents won't get defragged, and would trigger
# the following output
if [ $new_regular == $old_regular ]; then
	echo "regular extents didn't get defragged"
fi

# In v5.10 and earlier kernel, autodefrag may choose to defrag holes,
# which should be avoided.
if [ "$new_hole" != "$old_hole" ]; then
	echo "hole extents 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