tests/btrfs/093

#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (C) 2015 SUSE Linux Products GmbH. All Rights Reserved.
#
# FS QA Test No. btrfs/093
#
# Test btrfs file range cloning with the same file as a source and destination.
#
# This tests a specific scenario where the extent layout of the file confused
# the clone ioctl implementation making it return -EEXIST to userspace.
# This issue was fixed by the following linux kernel patch:
#
#    Btrfs: fix range cloning when same inode used as source and destination
#
. ./common/preamble
_begin_fstest auto quick clone

. ./common/filter

_require_scratch
_require_cloner

# Create a file with an extent layout that confused the btrfs clone ioctl
# implementation. The first extent item that is cloned by the second call
# to the cloner program will have only a trailing part of it referenced by
# a new extent item, since the source offset starts in the middle of that
# extent. This confused the clone ioctl because after inserting this new
# extent item it would immediately after process it again thinking it
# corresponded to an extent that existed before - this made it attempt to
# insert a duplicated extent item pointing to the same extent again, which
# made it return an -EEXIST error to userspace and turn the filesystem to
# readonly mode (since the current transaction got aborted).
test_clone()
{
	local bs=$1

	$XFS_IO_PROG -f -c "pwrite -S 0xaa $((2 * $bs)) $((2 * $bs))" \
		$SCRATCH_MNT/foo | _filter_xfs_io

	$CLONER_PROG -s $((3 * $bs)) -d $((267 * $bs)) -l 0 $SCRATCH_MNT/foo \
		$SCRATCH_MNT/foo
	$CLONER_PROG -s $((217 * $bs)) -d $((95 * $bs)) -l 0 $SCRATCH_MNT/foo \
		$SCRATCH_MNT/foo

	echo "File digest after clone operations using same file as source and destination"
	md5sum $SCRATCH_MNT/foo | _filter_scratch

	# Test cloning using different source and destination files for the
	# same exact data - it must produce the exact same result as the case
	# before.
	$XFS_IO_PROG -f -c "pwrite -S 0xaa $((2 * $bs)) $((2 * $bs))" \
		$SCRATCH_MNT/a | _filter_xfs_io
	cp $SCRATCH_MNT/a $SCRATCH_MNT/b

	$CLONER_PROG -s $((3 * $bs)) -d $((267 * $bs)) -l 0 $SCRATCH_MNT/a \
		$SCRATCH_MNT/b

	cp $SCRATCH_MNT/b $SCRATCH_MNT/foo2
	$CLONER_PROG -s $((217 * $bs)) -d $((95 * $bs)) -l 0 $SCRATCH_MNT/b \
		$SCRATCH_MNT/foo2

	echo "File digest after clone operations using different files as source and destination"
	md5sum $SCRATCH_MNT/foo2 | _filter_scratch

}

# Make sure the test passes offsets and lengths to the btrfs clone ioctl that
# are multiples of the fs block size. Currently the block size on btrfs must
# be a multiple of the page size, so use a 64Kb fs block size in order to be
# able to test on every platform supported by linux.
bs=$((64 * 1024))

echo "Testing without the no-holes feature"
_scratch_mkfs "-O ^no-holes -n $bs" >>$seqres.full 2>&1
_scratch_mount
test_clone $bs
_check_scratch_fs

echo -e "\nTesting with the no-holes feature"
_scratch_unmount
_scratch_mkfs "-O no-holes -n $bs" >>$seqres.full 2>&1
_scratch_mount
test_clone $bs

status=0
exit