tests/generic/416

#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2017 Fujitsu.  All Rights Reserved.
#
# FS QA Test 416
#
# Test fs behavior when large write request can't be met by one single extent
#
# Inspired by a bug in a btrfs fix, which doesn't get exposed by current test
# cases
#
. ./common/preamble
_begin_fstest auto enospc

# Import common functions.
. ./common/filter


# Modify as appropriate.
_require_scratch

fs_size=$((128 * 1024 * 1024))
page_size=$(_get_page_size)

# We will never reach this number though
nr_files=$(($fs_size / $page_size))

# Use small fs to make the fill more faster
_scratch_mkfs_sized $fs_size >> $seqres.full 2>&1

_scratch_mount

fill_fs()
{
	dir=$1
	for i in $(seq -w $nr_files); do
		# xfs_io can't return correct value when it hit ENOSPC, use
		# dd here to detect ENOSPC
		dd if=/dev/zero of=$SCRATCH_MNT/$i bs=$page_size count=1 \
			&> /dev/null
		if [ $? -ne 0 ]; then
			break
		fi
	done
}

fill_fs $SCRATCH_MNT

# remount to sync every thing into fs, and drop all cache
_scratch_remount

# remove all files with odd file names, which should free near half
# of the space
rm $SCRATCH_MNT/*[13579]
_scratch_sync

# We should be able to write at least 1/8 of the whole fs size
# The number 1/8 is for btrfs, which only has about 47M for data.
# And half of the 47M is already taken up, so only 1/8 is safe here
$XFS_IO_PROG -f -c "pwrite 0 $(($fs_size / 8))" $SCRATCH_MNT/large_file | \
	_filter_xfs_io

# success, all done
status=0
exit