apfstests/tests/btrfs/109

#! /bin/bash
# FS QA Test No. btrfs/109
#
# Test that a send operation works correctly with reflinked files (cloned
# extents which multiple files point to) that have compressed extents.
#
#-----------------------------------------------------------------------
# Copyright (C) 2015 SUSE Linux Products GmbH. All Rights Reserved.
# Author: Filipe Manana <fdmanana@suse.com>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it would be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write the Free Software Foundation,
# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
#-----------------------------------------------------------------------
#

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
_need_to_be_root
_require_cp_reflink

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 "-o compress"

# Create our file with an extent of 100K starting at file offset 0K.
$XFS_IO_PROG -f -c "pwrite -S 0xaa 0K 100K"       \
		-c "fsync"                        \
		$SCRATCH_MNT/foo | _filter_xfs_io

# Rewrite part of the previous extent (its first 40K) and write a new 100K
# extent starting at file offset 100K.
$XFS_IO_PROG -c "pwrite -S 0xbb 0K 40K"    \
		-c "pwrite -S 0xcc 100K 100K"      \
		$SCRATCH_MNT/foo | _filter_xfs_io

# Our file foo now has 3 file extent items in its metadata:
#
# 1) One covering the file range 0 to 40K;
# 2) One covering the file range 40K to 100K, which points to the first extent
#    we wrote to the file and has a data offset field with value 40K (our file
#    no longer uses the first 40K of data from that extent);
# 3) One covering the file range 100K to 200K.

# Now clone our file foo into file bar.
cp --reflink=always $SCRATCH_MNT/foo $SCRATCH_MNT/bar

# Create our snapshot for the send operation.
_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 $SCRATCH_MNT/snap -f $send_files_dir/1.snap

# Now recreate the filesystem by receiving the send stream and verify we get
# the same file contents that the original filesystem had.
# Btrfs send used to issue a clone operation from foo's range [80K, 140K[ to
# bar's range [40K, 100K[ when cloning the extent pointed to by foo's second
# file extent item, this was incorrect because of bad accounting of the file
# extent item's data offset field. The correct range to clone from should have
# been [40K, 100K[.
_scratch_unmount
_scratch_mkfs >>$seqres.full 2>&1
_scratch_mount "-o compress"

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

echo "File digests in the new filesystem:"
# Must match the digests we got in the original filesystem.
md5sum $SCRATCH_MNT/snap/foo | _filter_scratch
md5sum $SCRATCH_MNT/snap/bar | _filter_scratch

status=0
exit