apfstests/tests/btrfs/108

#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (C) 2015 SUSE Linux Products GmbH. All Rights Reserved.
#
# FS QA Test No. btrfs/108
#
# Test that a send operation works correctly with reflinked files (cloned
# extents which multiple files point to).
#
seq=`basename $0`
seqres=$RESULT_DIR/$seq
echo "QA output created by $seq"

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

_cleanup()
{
	cd /
	rm -fr $send_files_dir
	rm -f $tmp.*
}

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

# real QA test starts here
_supported_fs btrfs
_supported_os Linux
_require_scratch
_require_cp_reflink
_require_xfs_io_command "fpunch"

send_files_dir=$TEST_DIR/btrfs-test-$seq

rm -f $seqres.full
rm -fr $send_files_dir
mkdir $send_files_dir

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

# Create our test file with a single 100K extent.
$XFS_IO_PROG -f -c "pwrite -S 0xaa 0K 100K" $SCRATCH_MNT/foo | _filter_xfs_io

# Clone our file into a new file named bar.
cp --reflink=always $SCRATCH_MNT/foo $SCRATCH_MNT/bar

# Now overwrite parts of our foo file.
$XFS_IO_PROG -c "pwrite -S 0xbb 50K 10K" \
	-c "pwrite -S 0xcc 90K 10K" \
	-c "fpunch 70K 10k" \
	$SCRATCH_MNT/foo | _filter_xfs_io

_run_btrfs_util_prog subvolume snapshot -r $SCRATCH_MNT $SCRATCH_MNT/snap

echo "File digests in the original filesystem:"
md5sum $SCRATCH_MNT/snap/foo | _filter_scratch
md5sum $SCRATCH_MNT/snap/bar | _filter_scratch

_run_btrfs_util_prog send -f $send_files_dir/1.snap $SCRATCH_MNT/snap

# Now recreate the filesystem by receiving the send stream and verify we get
# the same file contents that the original filesystem had.
_scratch_unmount
_scratch_mkfs >>$seqres.full 2>&1
_scratch_mount

_run_btrfs_util_prog receive -f $send_files_dir/1.snap $SCRATCH_MNT

# We expect the destination filesystem to have exactly the same file data as
# the original filesystem.
# The btrfs send implementation had a bug where it sent a clone operation from
# file foo into file bar covering the whole [0, 100K[ range after creating
# and writing the file foo. This was incorrect because the file bar now included
# the updates done to file foo after we cloned foo to bar, breaking the COW
# nature of reflink copies (cloned extents).
echo "File digests in the new filesystem:"
md5sum $SCRATCH_MNT/snap/foo | _filter_scratch
md5sum $SCRATCH_MNT/snap/bar | _filter_scratch

status=0
exit