tests/btrfs/035

#!/bin/bash
# FS QA Test No. btrfs/035
#
# Regression test for overwriting clones
#
#-----------------------------------------------------------------------
# Copyright (C) 2014 SUSE Linux Products GmbH. 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
#
#-----------------------------------------------------------------------
#

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

here=`pwd`
tmp=/tmp/$$
status=1	# failure is the default!

_cleanup()
{
    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
_supported_fs btrfs
_supported_os Linux
_require_scratch
_require_cloner

_scratch_mkfs > /dev/null 2>&1
_scratch_mount

src_str="aaaaaaaaaa"

echo -n "$src_str" > $SCRATCH_MNT/src

$CLONER_PROG $SCRATCH_MNT/src  $SCRATCH_MNT/src.clone1

src_str="bbbbbbbbbbcccccccccc"

echo -n "$src_str" > $SCRATCH_MNT/src

$CLONER_PROG $SCRATCH_MNT/src $SCRATCH_MNT/src.clone2

snap_src_sz=`ls -lah $SCRATCH_MNT/src.clone1 | awk '{print $5}'`
echo "attempting ioctl (src.clone1 src)"
$CLONER_PROG -s 0 -d 0 -l ${snap_src_sz} \
	$SCRATCH_MNT/src.clone1 $SCRATCH_MNT/src

# The clone operation should have failed. If it did not it meant we had data
# loss, because file "src.clone1" has an inline extent which is 10 bytes long
# while file "src" has an inline extent which is 20 bytes long. The clone
# operation would remove the inline extent of "src" and then copy the inline
# extent from "src.clone1" into "src", which means we would lose the last 10
# bytes of data from "src" (on read we would get 0x00 as the value for any
# of those 10 bytes, because the file's size remains as 20 bytes).
echo "File src data after attempt to clone from src.clone1 into src:"
od -t x1 $SCRATCH_MNT/src

snap_src_sz=`ls -lah $SCRATCH_MNT/src.clone2 | awk '{print $5}'`
echo "attempting ioctl (src.clone2 src)"
$CLONER_PROG -s 0 -d 0 -l ${snap_src_sz} \
	$SCRATCH_MNT/src.clone2 $SCRATCH_MNT/src

# The clone operation should have succeeded.
echo "File src data after attempt to clone from src.clone2 into src:"
od -t x1 $SCRATCH_MNT/src

status=0 ; exit