tests/btrfs/103

#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (C) 2015 SUSE Linux Products GmbH. All Rights Reserved.
#
# FSQA Test No. 103
#
# Regression test for file read corruption when using compressed extents that
# are shared by multiple consecutive ranges of the same file.
#
. ./common/preamble
_begin_fstest auto quick clone compress

# Import common functions.
. ./common/filter

# real QA test starts here
_supported_fs btrfs
_require_scratch
_require_cloner

test_clone_and_read_compressed_extent()
{
	local mount_opts=$1

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

	BLOCK_SIZE=$(_get_block_size $SCRATCH_MNT)

	# Create a test file with a single extent that is compressed (the
	# data we write into it is highly compressible no matter which
	# compression algorithm is used, zlib or lzo).
	$XFS_IO_PROG -f -c "pwrite -S 0xaa 0K $((1 * $BLOCK_SIZE))" \
		-c "pwrite -S 0xbb $((1 * $BLOCK_SIZE)) $((2 * $BLOCK_SIZE))" \
		-c "pwrite -S 0xcc $((3 * $BLOCK_SIZE)) $((1 * $BLOCK_SIZE))" \
		$SCRATCH_MNT/foo | _filter_xfs_io_blocks_modified

	# Now clone our extent into an adjacent offset.
	$CLONER_PROG -s $((1 * $BLOCK_SIZE)) -d $((4 * $BLOCK_SIZE)) \
		     -l $((2 * $BLOCK_SIZE)) $SCRATCH_MNT/foo $SCRATCH_MNT/foo

	# Same as before but for this file we clone the extent into a lower
	# file offset.
	$XFS_IO_PROG -f \
		-c "pwrite -S 0xaa $((2 * $BLOCK_SIZE)) $((1 * $BLOCK_SIZE))" \
		-c "pwrite -S 0xbb $((3 * $BLOCK_SIZE)) $((2 * $BLOCK_SIZE))" \
		-c "pwrite -S 0xcc $((5 * $BLOCK_SIZE)) $((1 * $BLOCK_SIZE))" \
		$SCRATCH_MNT/bar | _filter_xfs_io_blocks_modified

	$CLONER_PROG -s $((3 * $BLOCK_SIZE)) -d 0 -l $((2 * $BLOCK_SIZE)) \
		$SCRATCH_MNT/bar $SCRATCH_MNT/bar

	echo "File contents before unmounting filesystem:"
	echo "foo:"
	od -t x1 $SCRATCH_MNT/foo | _filter_od
	echo "bar:"
	od -t x1 $SCRATCH_MNT/bar | _filter_od

	# Evicting the inode or clearing the page cache before reading again
	# the file would also trigger the bug - reads were returning all bytes
	# in the range corresponding to the second reference to the extent with
	# a value of 0, but the correct data was persisted (it was a bug
	# exclusively in the read path). The issue happened only if the same
	# readpages() call targeted pages belonging to the first and second
	# ranges that point to the same compressed extent.
	_scratch_cycle_mount

	echo "File contents after mounting filesystem again:"
	# Must match the same contents we got before.
	echo "foo:"
	od -t x1 $SCRATCH_MNT/foo | _filter_od
	echo "bar:"
	od -t x1 $SCRATCH_MNT/bar | _filter_od
}

echo -e "\nTesting with zlib compression..."
test_clone_and_read_compressed_extent "-o compress=zlib"

_scratch_unmount

echo -e "\nTesting with lzo compression..."
test_clone_and_read_compressed_extent "-o compress=lzo"

status=0
exit