#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2019 Facebook.  All Rights Reserved.
#
# FS QA Test 590
#
# Test commit 0c4da70c83d4 ("xfs: fix realtime file data space leak") and
# 69ffe5960df1 ("xfs: don't check for AG deadlock for realtime files in
# bunmapi"). On XFS without the fixes, truncate will hang forever. On other
# filesystems, this just tests writing into big fallocates.
#
seq=`basename $0`
seqres=$RESULT_DIR/$seq
echo "QA output created by $seq"

here=`pwd`
tmp=/tmp/$$
status=1	# failure is the default!
trap "_cleanup; exit \$status" 0 1 2 3 15

_cleanup()
{
	cd /
	rm -f $tmp.*
	test -n "$loop" && _destroy_loop_device "$loop"
	rm -f "$TEST_DIR/$seq"
}

. ./common/rc
. ./common/filter

rm -f $seqres.full

_supported_fs generic
_require_scratch_nocheck
_require_xfs_io_command "falloc"

maxextlen=$((0x1fffff))
bs=4096
rextsize=4
filesz=$(((maxextlen + 1) * bs))

must_disable_feature() {
	local feat="$1"

	# If mkfs doesn't know about the feature, we don't need to disable it
	$MKFS_XFS_PROG --help 2>&1 | grep -q "${feat}=0" || return 1

	# If turning the feature on works, we don't need to disable it
	_scratch_mkfs_xfs_supported -m "${feat}=1" "${disabled_features[@]}" \
		> /dev/null 2>&1 && return 1

	# Otherwise mkfs knows of the feature and formatting with it failed,
	# so we do need to mask it.
	return 0
}

extra_options=""
# If we're testing XFS, set up the realtime device to reproduce the bug.
if [[ $FSTYP = xfs ]]; then
	# If we don't have a realtime device, set up a loop device on the test
	# filesystem.
	if [[ $USE_EXTERNAL != yes || -z $SCRATCH_RTDEV ]]; then
		_require_test
		loopsz="$((filesz + (1 << 26)))"
		_require_fs_space "$TEST_DIR" $((loopsz / 1024))
		$XFS_IO_PROG -c "truncate $loopsz" -f "$TEST_DIR/$seq"
		loop="$(_create_loop_device "$TEST_DIR/$seq")"
		USE_EXTERNAL=yes
		SCRATCH_RTDEV="$loop"
		disabled_features=()

		# disable reflink if not supported by realtime devices
		must_disable_feature reflink &&
			disabled_features=(-m reflink=0)

		# disable rmap if not supported by realtime devices
		must_disable_feature rmapbt &&
			disabled_features+=(-m rmapbt=0)
	fi
	extra_options="$extra_options -r extsize=$((bs * rextsize))"
	extra_options="$extra_options -d agsize=$(((maxextlen + 1) * bs / 2)),rtinherit=1"

	_scratch_mkfs $extra_options "${disabled_features[@]}" >>$seqres.full 2>&1
	_try_scratch_mount >>$seqres.full 2>&1 || \
		_notrun "mount failed, kernel doesn't support realtime?"
	_scratch_unmount
else
	_scratch_mkfs $extra_options >>$seqres.full 2>&1
fi
_scratch_mount
_require_fs_space "$SCRATCH_MNT" $((filesz / 1024))

# Allocate maxextlen + 1 blocks. As long as the allocator does something sane,
# we should end up with two extents that look something like:
#
# u3.bmx[0-1] = [startoff,startblock,blockcount,extentflag]
# 0:[0,0,2097148,1]
# 1:[2097148,2097148,4,1]
#
# Extent 0 has blockcount = ALIGN_DOWN(maxextlen, rextsize). Extent 1 is
# adjacent and has blockcount = rextsize. Both are unwritten.
$XFS_IO_PROG -c "falloc 0 $filesz" -c fsync -f "$SCRATCH_MNT/file"

# Write extent 0 + one block of extent 1. Our extents should end up like so:
#
# u3.bmx[0-1] = [startoff,startblock,blockcount,extentflag]
# 0:[0,0,2097149,0]
# 1:[2097149,2097149,3,1]
#
# Extent 0 is written and has blockcount = ALIGN_DOWN(maxextlen, rextsize) + 1,
# Extent 1 is adjacent, unwritten, and has blockcount = rextsize - 1 and
# startblock % rextsize = 1.
#
# The -b is just to speed things up (doing GBs of I/O in 4k chunks kind of
# sucks).
$XFS_IO_PROG -c "pwrite -b 1M -W 0 $(((maxextlen + 2 - rextsize) * bs))" \
	"$SCRATCH_MNT/file" >> "$seqres.full"

# Truncate the extents.
$XFS_IO_PROG -c "truncate 0" -c fsync "$SCRATCH_MNT/file"

# We need to do this before the loop device gets torn down.
_scratch_unmount
_check_scratch_fs

echo "Silence is golden"
status=0
exit