#! /bin/bash
# FSQA Test No. 276
#
# Run fsstress to create a reasonably strange file system, make a
# snapshot and run more fsstress. Then select some files from that fs,
# run filefrag to get the extent mapping and follow the backrefs.
# We check to end up back at the original file with the correct offset.
#
#-----------------------------------------------------------------------
# Copyright (C) 2011 STRATO.  All rights reserved.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it would be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write the Free Software Foundation,
# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
#
#-----------------------------------------------------------------------
#
# creator
owner=list.btrfs@jan-o-sch.net

seq=`basename $0`
echo "QA output created by $seq"

here=`pwd`
tmp=/tmp/$$
status=1

_cleanup()
{
	echo "*** unmount"
	umount $SCRATCH_MNT 2>/dev/null
	rm -f $tmp.*
}
trap "_cleanup; exit \$status" 0 1 2 3 15

# get standard environment, filters and checks
. ./common.rc
. ./common.filter

# real QA test starts here
_need_to_be_root
_supported_fs btrfs
_supported_os Linux
_require_scratch

_require_nobigloopfs
_require_btrfs inspect-internal
_require_command "/usr/sbin/filefrag"

rm -f $seq.full

FILEFRAG_FILTER='if (/, blocksize (\d+)/) {$blocksize = $1; next} ($ext, '\
'$logical, $physical, $expected, $length, $flags) = (/^\s*(\d+)\s+(\d+)'\
'\s+(\d+)\s+(?:(\d+)\s+)?(\d+)\s+(.*)/) or next; $flags =~ '\
'/(?:^|,)inline(?:,|$)/ and next; print $physical * $blocksize, "#", '\
'$length * $blocksize, "#", $logical * $blocksize, " "'

# this makes filefrag output script readable by using a perl helper.
# output is one extent per line, with three numbers separated by '#'
# the numbers are: physical, length, logical (all in bytes)
# sample output: "1234#10#5678" -> physical 1234, length 10, logical 5678
_filter_extents()
{
	tee -a $seq.full | $PERL_PROG -ne "$FILEFRAG_FILTER"
}

_check_file_extents()
{
	cmd="filefrag -vx $1"
	echo "# $cmd" >> $seq.full
	out=`$cmd | _filter_extents`
	if [ -z "$out" ]; then
		return 1
	fi
	echo "after filter: $out" >> $seq.full
	echo $out
	return 0
}

# use a logical address and walk the backrefs back to the inode.
# compare to the expected result.
# returns 0 on success, 1 on error (with output made)
_btrfs_inspect_addr()
{
	mp=$1
	addr=$2
	expect_addr=$3
	expect_inum=$4
	file=$5
	cmd="$BTRFS_UTIL_PROG inspect-internal logical-resolve -P $addr $mp"
	echo "# $cmd" >> $seq.full
	out=`$cmd`
	echo "$out" >> $seq.full
	grep_expr="inode $expect_inum offset $expect_addr root"
	echo "$out" | grep "^$grep_expr 5$" >/dev/null
	ret=$?
	if [ $ret -eq 0 ]; then
		# look for a root number that is not 5
		echo "$out" | grep "^$grep_expr \([0-46-9][0-9]*\|5[0-9]\+\)$" \
			>/dev/null
		ret=$?
	fi
	if [ $ret -eq 0 ]; then
		return 0
	fi
	echo "unexpected output from"
	echo "	$cmd"
	echo "expected inum: $expect_inum, expected address: $expect_addr,"\
		"file: $file, got:"
	echo "$out"
	return 1
}

# use an inode number and walk the backrefs back to the file name.
# compare to the expected result.
# returns 0 on success, 1 on error (with output made)
_btrfs_inspect_inum()
{
	file=$1
	inum=$2
	snap_name=$3
	mp="$SCRATCH_MNT/$snap_name"
	cmd="$BTRFS_UTIL_PROG inspect-internal inode-resolve $inum $mp"
	echo "# $cmd" >> $seq.full
	out=`$cmd`
	echo "$out" >> $seq.full
	grep_expr="^$file$"
	cnt=`echo "$out" | grep "$grep_expr" | wc -l`
	if [ $cnt -ge "1" ]; then
		return 0
	fi
	echo "unexpected output from"
	echo "	$cmd"
	echo "expected path: $file, got:"
	echo "$out"
	return 1
}

_btrfs_inspect_check()
{
	file=$1
	physical=$2
	length=$3
	logical=$4
	snap_name=$5
	cmd="stat -c %i $file"
	echo "# $cmd" >> $seq.full
	inum=`$cmd`
	echo "$inum" >> $seq.full
	_btrfs_inspect_addr $SCRATCH_MNT $physical $logical $inum $file
	ret=$?
	if [ $ret -eq 0 ]; then
		_btrfs_inspect_inum $file $inum $snap_name
		ret=$?
	fi
	return $ret
}

run_check()
{
	echo "# $@" >> $seq.full 2>&1
	"$@" >> $seq.full 2>&1 || _fail "failed: '$@'"
}

workout()
{
	fsz=$1
	nfiles=$2
	procs=$3
	snap_name=$4

	umount $SCRATCH_DEV >/dev/null 2>&1
	echo "*** mkfs -dsize=$fsz"    >>$seq.full
	echo ""                                     >>$seq.full
	_scratch_mkfs_sized $fsz >>$seq.full 2>&1 \
		|| _fail "size=$fsz mkfs failed"
	run_check _scratch_mount
	# -w ensures that the only ops are ones which cause write I/O
	run_check $FSSTRESS_PROG -d $SCRATCH_MNT -w -p $procs -n 1000 \
		$FSSTRESS_AVOID

	run_check $BTRFS_UTIL_PROG subvol snap $SCRATCH_MNT \
		$SCRATCH_MNT/$snap_name

	run_check umount $SCRATCH_DEV >/dev/null 2>&1
	run_check _scratch_mount "-o compress=lzo"

	# make some noise but ensure we're not touching existing data
	# extents.
	run_check $FSSTRESS_PROG -d $SCRATCH_MNT -p $procs -n 2000 \
		-z -f chown=3 -f link=1 -f mkdir=2 -f mknod=2 \
		-f rename=2 -f setxattr=1 -f symlink=2
	clean_dir="$SCRATCH_MNT/next"
	mkdir $clean_dir
	# now make more files to get a higher tree
	run_check $FSSTRESS_PROG -d $clean_dir -w -p $procs -n 2000 \
		$FSSTRESS_AVOID
	run_check umount $SCRATCH_DEV >/dev/null 2>&1
	run_check _scratch_mount "-o atime"

	cnt=0
	errcnt=0
	dir="$SCRATCH_MNT/$snap_name/"
	for file in `find $dir -name f\* -size +0 | sort -R`; do
		extents=`_check_file_extents $file`
		ret=$?
		if [ $ret -ne 0 ]; then
			continue;
		fi
		for i in $extents; do
			physical=$i
			length=$i
			logical=$i
			physical=`echo $physical | sed -e 's/#.*//'`
			length=`echo $length | sed -e 's/[^#]+#//'`
			length=`echo $length | sed -e 's/#.*//'`
			logical=`echo $logical | sed -e 's/.*#//'`
			_btrfs_inspect_check $file $physical $length $logical \
						$snap_name
			ret=$?
			if [ $ret -ne 0 ]; then
				errcnt=`expr $errcnt + 1`
			fi
		done
		cnt=`expr $cnt + 1`
		if [ $cnt -ge $nfiles ]; then
			break
		fi
	done
	if [ $errcnt -gt 0 ]; then
		_fail "test failed: $errcnt error(s)"
	fi
}

echo "*** test backref walking"

snap_name="snap1"
filesize=`expr 2000 \* 1024 \* 1024`
nfiles=4
numprocs=1

workout $filesize $nfiles $numprocs $snap_name

echo "*** done"
status=0
exit