iotests: Test qemu-img convert -S 0 behavior

Passing -S 0 to qemu-img convert should result in all source data being
copied to the output, even if that source data is known to be 0. The
output image should therefore have exactly the same size on disk as an
image which we explicitly filled with data.

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

tests/qemu-iotests/150

+#!/bin/bash
+#
+# Test that qemu-img convert -S 0 fully allocates the target image
+#
+# Copyright (C) 2016 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 generic
+_supported_proto file
+_supported_os Linux
+
+
+on_disk_size()
+{
+    du "$@" | sed -e 's/\t\+.*//'
+}
+
+
+img_size=1048576
+
+
+echo
+echo '=== Comparing empty image against sparse conversion ==='
+echo
+
+_make_test_img $img_size
+
+empty_size=$(on_disk_size "$TEST_IMG")
+
+
+$QEMU_IMG_PROG convert -O "$IMGFMT" -S 512 \
+    "json:{ 'driver': 'null-co', 'size': $img_size, 'read-zeroes': true }" \
+    "$TEST_IMG"
+
+sparse_convert_size=$(on_disk_size "$TEST_IMG")
+
+
+if [ "$empty_size" -eq "$sparse_convert_size" ]; then
+    echo 'Equal image size'
+else
+    echo 'Different image size'
+fi
+
+
+echo
+echo '=== Comparing full image against non-sparse conversion ==='
+echo
+
+_make_test_img $img_size
+$QEMU_IO -c "write 0 $img_size" "$TEST_IMG" | _filter_qemu_io
+
+full_size=$(on_disk_size "$TEST_IMG")
+
+
+$QEMU_IMG convert -O "$IMGFMT" -S 0 \
+    "json:{ 'driver': 'null-co', 'size': $img_size, 'read-zeroes': true }" \
+    "$TEST_IMG"
+
+non_sparse_convert_size=$(on_disk_size "$TEST_IMG")
+
+
+if [ "$full_size" -eq "$non_sparse_convert_size" ]; then
+    echo 'Equal image size'
+else
+    echo 'Different image size'
+fi
+
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0

tests/qemu-iotests/150.out

+QA output created by 150
+
+=== Comparing empty image against sparse conversion ===
+
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576
+Equal image size
+
+=== Comparing full image against non-sparse conversion ===
+
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576
+wrote 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+Equal image size
+*** done

tests/qemu-iotests/group

@@ -151,3 +151,4 @@
 146 auto quick
 148 rw auto quick
 149 rw auto sudo
+150 rw auto quick