#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2015, Oracle and/or its affiliates.  All Rights Reserved.
#
# FS QA Test No. 156
#
# Ensure that fallocate on reflinked files actually CoWs the shared blocks.
#   - Record fs block usage (0)
#   - Create a file and some reflink copies
#   - Record fs block usage (1)
#   - funshare half of one of the copies
#   - Record fs block usage (2)
#   - funshare all of the copies
#   - Record fs block usage (3)
#   - rewrite the original file
#   - Record fs block usage (4)
#   - Compare fs block usage of 0-4 to ensure that block usage behaves as
#     we expect.
#
# "funshare" refers to fallocate copy-on-writing the shared blocks
#
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/attr
. ./common/reflink

# real QA test starts here
_require_test_reflink
_require_cp_reflink
_require_xfs_io_command "funshare"

rm -f $seqres.full

testdir=$TEST_DIR/test-$seq
rm -rf $testdir
mkdir $testdir

echo "Create the original file blocks"
blksz="$(_get_block_size $testdir)"
blks=2000
margin='15%'
sz=$((blksz * blks))
free_blocks0=$(stat -f $testdir -c '%f')
nr=4
filesize=$((blksz * nr))
_pwrite_byte 0x61 0 $sz $testdir/file1 >> $seqres.full
_test_cycle_mount

echo "Create the reflink copies"
for i in `seq 2 $nr`; do
	_cp_reflink $testdir/file1 $testdir/file$i
done
_test_cycle_mount
free_blocks1=$(stat -f $testdir -c '%f')

echo "funshare part of a file"
$XFS_IO_PROG -f -c "funshare 0 $((sz / 2))" $testdir/file2
_test_cycle_mount

echo "funshare some of the copies"
$XFS_IO_PROG -f -c "funshare 0 $sz" $testdir/file2
$XFS_IO_PROG -f -c "funshare 0 $sz" $testdir/file3
_test_cycle_mount
free_blocks2=$(stat -f $testdir -c '%f')

echo "funshare the rest of the files"
$XFS_IO_PROG -f -c "funshare 0 $sz" $testdir/file4
$XFS_IO_PROG -f -c "funshare 0 $sz" $testdir/file1
_test_cycle_mount
free_blocks3=$(stat -f $testdir -c '%f')

echo "Rewrite the original file"
_pwrite_byte 0x65 0 $sz $testdir/file1 >> $seqres.full
_test_cycle_mount
free_blocks4=$(stat -f $testdir -c '%f')
#echo $free_blocks0 $free_blocks1 $free_blocks2 $free_blocks3 $free_blocks4

_within_tolerance "free blocks after reflinking" $free_blocks1 $((free_blocks0 - blks)) $margin -v

_within_tolerance "free blocks after nocow'ing some copies" $free_blocks2 $((free_blocks1 - (2 * blks))) $margin -v

_within_tolerance "free blocks after nocow'ing all copies" $free_blocks3 $((free_blocks2 - blks)) $margin -v

_within_tolerance "free blocks after overwriting original" $free_blocks4 $free_blocks3 $margin -v

_within_tolerance "free blocks after all tests" $free_blocks4 $((free_blocks0 - (4 * blks))) $margin -v

# success, all done
status=0
exit