iotests: Discarding compressed clusters on qcow2

Add a test which discards a compressed cluster on qcow2. This should
work without any problems.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

tests/qemu-iotests/090

@@ -0,0 +1,61 @@
+#!/bin/bash
+#
+# Test for discarding compressed clusters on qcow2 images
+#
+# Copyright (C) 2014 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=mreitz@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
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+_supported_fmt qcow2
+_supported_proto file
+_supported_os Linux
+
+IMG_SIZE=128K
+
+_make_test_img $IMG_SIZE
+
+$QEMU_IO -c 'write -c -P 42 0 64k' \
+         -c 'write -c -P 23 64k 64k' \
+         -c 'discard 64k 64k' \
+         "$TEST_IMG" | _filter_qemu_io
+
+$QEMU_IO -c 'read -P 0 64k 64k' "$TEST_IMG" | _filter_qemu_io
+
+_check_test_img
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0