tests/btrfs/132

#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2016 Fujitsu.  All Rights Reserved.
#
# FS QA Test 132
#
# Check if false ENOSPC will happen when parallel buffer write happens
# The problem is caused by incorrect metadata reservation for any buffered
# write whose max extent size is not 128M (including compression and in-band
# dedupe).
#
. ./common/preamble
_begin_fstest auto enospc

# Override the default cleanup function.
_cleanup()
{
	cd /
	rm -f $tmp.*
	kill $pids &> /dev/null
	wait
}

. ./common/filter

_require_scratch

# Use small filesystem to trigger the bug more easily
# It's highly recommened to run this test case with MKFS_OPTIONS="-n 64k"
# to further increase the possibility
# Since the false ENOSPC happens due to incorrect metadata reservation,
# larger nodesize and small fs will make it much easier to reproduce
_scratch_mkfs_sized $((512 * 1024 * 1024)) >> $seqres.full 2>&1

# Recommended to use MOUNT_OPTIONS="-o compress" to trigger the bug
_scratch_mount

sleep_time=$(($TIME_FACTOR * 30))
loop_writer()
{
	offset=$1
	len=$2
	file=$3

	while true; do
		# Only need stderr, and we need to specify small block size
		# but still large enough trigger compression
		$XFS_IO_PROG -c "pwrite -b 8K $offset $len" $file > /dev/null
	done
}

touch $SCRATCH_MNT/testfile

# Start 2 writter writting into the same file
# The file is 142M, which is smaller than 1/2 of the filesystem,
# so no other cause can lead to ENOSPC.
loop_writer 0 128M $SCRATCH_MNT/testfile &
pids=$!
loop_writer 128M 16M $SCRATCH_MNT/testfile &
pids="$pids $!"

sleep $sleep_time

kill $pids
wait

# Wait all writers really exits
while pgrep -f "$SCRATCH_MNT" > /dev/null; do
	sleep 1
done

echo "Silence is golden"
status=0
exit