qemu-iotests: add tests for rebasing zero clusters

If zero clusters are erroneously treated as unallocated, "qemu-img rebase"
will copy the backing file's contents onto the cluster.

The bug existed also in image streaming, but since the root cause was in
qcow2's is_allocated implementation it is enough to test it with qemu-img.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

tests/qemu-iotests/050

@@ -0,0 +1,75 @@
+#!/bin/bash
+#
+# Test qemu-img rebase with zero clusters
+#
+# Copyright (C) 2013 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=pbonzini@redhat.com
+
+seq=`basename $0`
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+
+_cleanup()
+{
+    _cleanup_test_img
+    rm -f $TEST_IMG.old
+    rm -f $TEST_IMG.new
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+_supported_fmt qcow2 qed
+_supported_proto file
+_supported_os Linux
+
+if test "$IMGFMT" = qcow2 && test $IMGOPTS = ""; then
+  IMGOPTS=compat=1.1
+fi
+
+echo
+echo "== Creating images =="
+
+size=10M
+_make_test_img $size
+$QEMU_IO -c "write -P 0x40 0 1048576" $TEST_IMG | _filter_qemu_io
+mv $TEST_IMG $TEST_IMG.old
+
+_make_test_img $size
+$QEMU_IO -c "write -P 0x5a 0 1048576" $TEST_IMG | _filter_qemu_io
+mv $TEST_IMG $TEST_IMG.new
+
+_make_test_img -b $TEST_IMG.old $size
+$QEMU_IO -c "write -z 0 1048576" $TEST_IMG | _filter_qemu_io
+
+echo
+echo "== Rebasing the image =="
+
+$QEMU_IMG rebase -b $TEST_IMG.new $TEST_IMG
+$QEMU_IO -c "read -P 0x00 0 1048576" $TEST_IMG | _filter_qemu_io
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0

tests/qemu-iotests/050.out

@@ -0,0 +1,17 @@
+QA output created by 050
+
+== Creating images ==
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=10485760 
+wrote 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=10485760 
+wrote 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=10485760 backing_file='TEST_DIR/t.IMGFMT.old' 
+wrote 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+== Rebasing the image ==
+read 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+*** done

tests/qemu-iotests/group

@@ -56,3 +56,4 @@
 047 rw auto
 048 img auto quick
 049 rw auto
+050 rw auto backing quick