tests/generic/098

#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (C) 2015 SUSE Linux Products GmbH. All Rights Reserved.
#
# FSQA Test No. 098
#
# Test that after truncating a file into the middle of a hole causes the new
# size of the file to be persisted after a clean unmount of the filesystem (or
# after the inode is evicted). This is for the case where all the data following
# the hole is not yet durably persisted, that is, that data is only present in
# the page cache.
#
# This test is motivated by an issue found in btrfs.
#
. ./common/preamble
_begin_fstest auto quick metadata

# Import common functions.
. ./common/filter

_require_scratch

# This test was motivated by an issue found in btrfs when the btrfs no-holes
# feature is enabled (introduced in kernel 3.14). So enable the feature if the
# fs being tested is btrfs.
if [ $FSTYP == "btrfs" ]; then
	_require_btrfs_fs_feature "no_holes"
	_require_btrfs_mkfs_feature "no-holes"
	MKFS_OPTIONS="$MKFS_OPTIONS -O no-holes"
fi

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

workout()
{
	local need_sync=$1

	# Create our test file with some data and durably persist it.
	$XFS_IO_PROG -t -f -c "pwrite -S 0xaa 0 128K" $SCRATCH_MNT/foo | _filter_xfs_io
	sync

	# Append some data to the file, increasing its size, and leave a hole between
	# the old size and the start offset if the following write. So our file gets
	# a hole in the range [128Kb, 256Kb[.
	$XFS_IO_PROG -c "pwrite -S 0xbb 256K 32K" $SCRATCH_MNT/foo | _filter_xfs_io

	# This 'sync' is to flush file extent on disk and update on-disk inode size.
	# This is required to trigger a bug in btrfs truncate where it updates on-disk
	# inode size incorrectly.
	if [ $need_sync -eq 1 ]; then
		sync
	fi

	# Now truncate our file to a smaller size that is in the middle of the hole we
	# previously created.
	# If we don't flush dirty page cache above, on most truncate
	# implementations the data we appended before gets discarded from
	# memory (with truncate_setsize()) and never ends up being written to
	# disk.
	$XFS_IO_PROG -c "truncate 160K" $SCRATCH_MNT/foo

	_scratch_cycle_mount

	# We expect to see a file with a size of 160Kb, with the first 128Kb of data all
	# having the value 0xaa and the remaining 32Kb of data all having the value 0x00
	echo "File content after remount:"
	od -t x1 $SCRATCH_MNT/foo
}

workout 0
# flush after each write
workout 1

status=0
exit