diff --git a/028 b/028
new file mode 100755
index 0000000..0ca220e
--- /dev/null
+++ b/028
@@ -0,0 +1,101 @@
+#!/bin/bash
+#
+# Test that backing files can be smaller than the image
+#
+# Copyright (C) 2010 IBM, Corp.
+#
+# Based on 017:
+# Copyright (C) 2009 Red Hat, Inc.
+#
+# 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; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will 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, see <http://www.gnu.org/licenses/>.
+#
+
+# creator
+owner=stefanha@linux.vnet.ibm.com
+
+seq=`basename $0`
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+
+_cleanup()
+{
+	_cleanup_test_img
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+. ./common.pattern
+
+# Any format supporting backing files except vmdk and qcow which do not support
+# smaller backing files.
+_supported_fmt qcow2
+_supported_os Linux
+
+# Choose a size that is not necessarily a cluster size multiple for image
+# formats that use clusters.  This will ensure that the base image doesn't end
+# precisely on a cluster boundary (the easy case).
+image_size=$(( 4 * 1024 * 1024 * 1024 + 3 * 512 ))
+
+# The base image is smaller than the image file
+base_size=$(( image_size - 1024 * 1024 * 1024 ))
+
+offset=$(( base_size - 32 * 1024 ))
+
+_make_test_img $base_size
+
+echo "Filling base image"
+echo
+
+# Fill end of base image with a pattern, skipping every other sector
+io writev $offset 512 1024 31
+
+_check_test_img
+
+echo "Creating test image with backing file"
+echo
+
+mv $TEST_IMG $TEST_IMG.base
+_make_test_img -b $TEST_IMG.base $image_size
+
+echo "Filling test image"
+echo
+
+# Write every other sector around where the base image ends
+io writev $(( offset + 512 )) 512 1024 63
+
+_check_test_img
+
+echo "Reading"
+echo
+
+# Base image sectors
+io readv $(( offset )) 512 1024 31
+
+# Image sectors
+io readv $(( offset + 512 )) 512 1024 63
+
+# Zero sectors beyond end of base image
+io_zero readv $(( offset + 32 * 1024 )) 512 1024 31
+
+_check_test_img
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0
diff --git a/028.out b/028.out
new file mode 100644
index 0000000..17460ed
--- /dev/null
+++ b/028.out
@@ -0,0 +1,458 @@
+QA output created by 028
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=3221227008 
+Filling base image
+
+=== IO: pattern 195
+qemu-io> wrote 512/512 bytes at offset 3221195264
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221196288
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221197312
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221198336
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221199360
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221200384
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221201408
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221202432
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221203456
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221204480
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221205504
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221206528
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221207552
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221208576
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221209600
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221210624
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221211648
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221212672
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221213696
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221214720
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221215744
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221216768
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221217792
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221218816
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221219840
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221220864
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221221888
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221222912
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221223936
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221224960
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221225984
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> No errors were found on the image.
+Creating test image with backing file
+
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=4294968832 backing_file='TEST_DIR/t.IMGFMT.base' 
+Filling test image
+
+=== IO: pattern 196
+qemu-io> wrote 512/512 bytes at offset 3221195776
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221196800
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221197824
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221198848
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221199872
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221200896
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221201920
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221202944
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221203968
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221204992
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221206016
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221207040
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221208064
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221209088
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221210112
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221211136
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221212160
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221213184
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221214208
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221215232
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221216256
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221217280
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221218304
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221219328
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221220352
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221221376
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221222400
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221223424
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221224448
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221225472
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221226496
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221227520
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221228544
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221229568
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221230592
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221231616
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221232640
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221233664
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221234688
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221235712
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221236736
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221237760
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221238784
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221239808
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221240832
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221241856
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221242880
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221243904
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221244928
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221245952
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221246976
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221248000
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221249024
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221250048
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221251072
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221252096
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221253120
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221254144
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221255168
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221256192
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221257216
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221258240
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 512/512 bytes at offset 3221259264
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> No errors were found on the image.
+Reading
+
+=== IO: pattern 195
+qemu-io> read 512/512 bytes at offset 3221195264
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221196288
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221197312
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221198336
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221199360
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221200384
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221201408
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221202432
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221203456
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221204480
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221205504
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221206528
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221207552
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221208576
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221209600
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221210624
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221211648
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221212672
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221213696
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221214720
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221215744
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221216768
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221217792
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221218816
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221219840
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221220864
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221221888
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221222912
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221223936
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221224960
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221225984
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> === IO: pattern 196
+qemu-io> read 512/512 bytes at offset 3221195776
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221196800
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221197824
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221198848
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221199872
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221200896
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221201920
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221202944
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221203968
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221204992
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221206016
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221207040
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221208064
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221209088
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221210112
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221211136
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221212160
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221213184
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221214208
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221215232
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221216256
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221217280
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221218304
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221219328
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221220352
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221221376
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221222400
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221223424
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221224448
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221225472
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221226496
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221227520
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221228544
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221229568
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221230592
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221231616
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221232640
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221233664
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221234688
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221235712
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221236736
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221237760
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221238784
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221239808
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221240832
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221241856
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221242880
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221243904
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221244928
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221245952
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221246976
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221248000
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221249024
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221250048
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221251072
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221252096
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221253120
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221254144
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221255168
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221256192
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221257216
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221258240
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221259264
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> === IO: pattern 0
+qemu-io> read 512/512 bytes at offset 3221228032
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221229056
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221230080
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221231104
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221232128
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221233152
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221234176
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221235200
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221236224
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221237248
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221238272
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221239296
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221240320
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221241344
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221242368
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221243392
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221244416
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221245440
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221246464
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221247488
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221248512
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221249536
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221250560
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221251584
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221252608
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221253632
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221254656
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221255680
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221256704
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221257728
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 512/512 bytes at offset 3221258752
+512.000000 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> No errors were found on the image.
+*** done
diff --git a/group b/group
index 4c8c419..b9e90f5 100644
--- a/group
+++ b/group
@@ -34,3 +34,4 @@
 025 rw auto
 026 rw blkdbg auto
 027 rw auto
+028 rw backing auto
