#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (C) 2023 SUSE Linux Products GmbH. All Rights Reserved.
#
# FS QA Test 283
#
# Test that send operations do the best cloning decisions when we have extents
# that are shared but some files refer to the full extent while others refer to
# only a section of the extent.
#
. ./common/preamble
_begin_fstest auto quick send clone fiemap

. ./common/filter
. ./common/reflink
. ./common/punch # for _filter_fiemap_flags

_supported_fs btrfs
_require_test
_require_scratch_reflink
_require_cp_reflink
_require_xfs_io_command "fiemap"
_require_fssum

_wants_kernel_commit c7499a64dcf6 \
	     "btrfs: send: optimize clone detection to increase extent sharing"

extent_size=$(( 128 * 1024 ))
if _scratch_btrfs_is_zoned; then
	zone_append_max=$(cat "/sys/block/$(_short_dev $SCRATCH_DEV)/queue/zone_append_max_bytes")
	if [[ $zone_append_max -gt 0 && $zone_append_max -lt $extent_size ]]; then
		_notrun "zone append max $zone_append_max is smaller than wanted extent size $extent_size"
	fi
fi

send_files_dir=$TEST_DIR/btrfs-test-$seq
send_stream=$send_files_dir/snap.stream
snap_fssum=$send_files_dir/snap.fssum

rm -fr $send_files_dir
mkdir $send_files_dir

_scratch_mkfs >> $seqres.full 2>&1
_scratch_mount

# When using compression, btrfs limits the extent size to 128K, so do not do
# larger writes and then expect larger extents, as that would break the test
# if we are run with compression enabled through $MOUNT_OPTIONS (resulting in
# mismatch with the golden output).
$XFS_IO_PROG -f -c "pwrite -S 0xab -b 128K 0 128K" $SCRATCH_MNT/foo | _filter_xfs_io

# Now clone file foo twice, which will make the 128K extent shared 3 times.
_cp_reflink $SCRATCH_MNT/foo $SCRATCH_MNT/bar
_cp_reflink $SCRATCH_MNT/foo $SCRATCH_MNT/baz

# Overwrite the second half of file foo.
$XFS_IO_PROG -c "pwrite -S 0xcd -b 64K 64K 64K" $SCRATCH_MNT/foo | _filter_xfs_io

echo "Creating snapshot and a send stream for it..."
_btrfs subvolume snapshot -r $SCRATCH_MNT $SCRATCH_MNT/snap

$BTRFS_UTIL_PROG send -f $send_stream $SCRATCH_MNT/snap 2>&1 | _filter_scratch

$FSSUM_PROG -A -f -w $snap_fssum $SCRATCH_MNT/snap

echo "Creating a new filesystem to receive the send stream..."
_scratch_unmount
_scratch_mkfs >> $seqres.full 2>&1
_scratch_mount

$BTRFS_UTIL_PROG receive -f $send_stream $SCRATCH_MNT

echo "Verifying data matches the original filesystem..."
$FSSUM_PROG -r $snap_fssum $SCRATCH_MNT/snap

# Now verify that all extents, for all files, are shared.

# File 'foo' should have a single 128K extent, which is shared because its first
# half is referred by files 'bar' and 'baz'.
echo -e "\nfiemap of file foo:\n"
$XFS_IO_PROG -r -c "fiemap -v" $SCRATCH_MNT/snap/foo | _filter_fiemap_flags

# File 'bar' should have two 64K shared extents. The first one is shared with
# files 'foo' and 'baz', while the second one is only shared with file 'baz'.
echo -e "\nfiemap of file bar:\n"
$XFS_IO_PROG -r -c "fiemap -v" $SCRATCH_MNT/snap/bar | _filter_fiemap_flags

# File 'baz' should have two 64K shared extents. The first one is shared with
# files 'foo' and 'bar', while the second one is only shared with file 'bar'.
echo -e "\nfiemap of file baz:\n"
$XFS_IO_PROG -r -c "fiemap -v" $SCRATCH_MNT/snap/baz | _filter_fiemap_flags

# success, all done
status=0
exit