#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2015, Oracle and/or its affiliates.  All Rights Reserved.
#
# FS QA Test No. 186
#
# Ensuring that copy on write in buffered mode works when free space
# is heavily fragmented.
#   - Create two files
#   - Reflink the odd blocks of the first file into a third file.
#   - Reflink the even blocks of the second file into the third file.
#   - Try to fragment the free space by allocating a huge file and
#     punching out every other block.
#   - CoW across the halfway mark.
#   - Check that the files are now different where we say they're different.
#
seq=`basename $0`
seqres=$RESULT_DIR/$seq
echo "QA output created by $seq"

here=`pwd`
tmp=/tmp/$$
status=1    # failure is the default!
trap "_cleanup; exit \$status" 0 1 2 3 15

_cleanup()
{
    cd /
#    rm -rf $tmp.* $testdir
}

# get standard environment, filters and checks
. ./common/rc
. ./common/filter
. ./common/reflink

# real QA test starts here
_supported_os Linux
_require_scratch_reflink
_require_cp_reflink
_require_xfs_io_command "falloc"
_require_xfs_io_command "fpunch"
test $FSTYP = "btrfs" && _notrun "Can't fragment free space on btrfs."

rm -f $seqres.full

_fragment_freesp()
{
	file=$1

	# consume nearly all available space (leave ~1MB)
	avail=`_get_available_space $SCRATCH_MNT`
	echo "$avail bytes left"
	filesize=$((avail - 1048576))
	$XFS_IO_PROG -fc "truncate $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}

	# Punch out whatever we need
	seq 1 $((nr * 4)) | while read f; do
		$XFS_IO_PROG -f -c "fpunch $((f * 2 * blksz)) $blksz" $file
	done
}

echo "Format and mount"
_scratch_mkfs > $seqres.full 2>&1
_scratch_mount >> $seqres.full 2>&1

testdir=$SCRATCH_MNT/test-$seq
mkdir $testdir

echo "Create the original files"
blksz=65536
nr=1024
filesize=$((blksz * nr))
_pwrite_byte 0x61 0 $filesize $testdir/file1 >> $seqres.full
_pwrite_byte 0x62 0 $filesize $testdir/file2 >> $seqres.full
seq 0 2 $((nr-1)) | while read f; do
	_reflink_range $testdir/file1 $((blksz * f)) $testdir/file3 $((blksz * f)) $blksz >> $seqres.full
	_pwrite_byte 0x61 $((blksz * f)) $blksz $testdir/file3.chk >> $seqres.full
done
seq 1 2 $((nr-1)) | while read f; do
	_reflink_range $testdir/file2 $((blksz * f)) $testdir/file3 $((blksz * f)) $blksz >> $seqres.full
	_pwrite_byte 0x62 $((blksz * f)) $blksz $testdir/file3.chk >> $seqres.full
done
_scratch_cycle_mount
_fragment_freesp $testdir/bigfile >> $seqres.full 2>&1
filesize=$((blksz * nr))
_scratch_cycle_mount

echo "Compare files"
md5sum $testdir/file1 | _filter_scratch
md5sum $testdir/file2 | _filter_scratch
md5sum $testdir/file3 | _filter_scratch
md5sum $testdir/file3.chk | _filter_scratch

echo "CoW with multiple extents?"
cowoff=$((filesize / 4))
cowsz=$((filesize / 2))
$XFS_IO_PROG -f -c "pwrite -S 0x63 -b $cowsz $cowoff $cowsz" $testdir/file3 >> $seqres.full
_pwrite_byte 0x63 $cowoff $cowsz $testdir/file3.chk >> $seqres.full
_scratch_cycle_mount

echo "Compare files"
md5sum $testdir/file1 | _filter_scratch
md5sum $testdir/file2 | _filter_scratch
md5sum $testdir/file3 | _filter_scratch
md5sum $testdir/file3.chk | _filter_scratch

# success, all done
status=0
exit