1 files changed, 83 insertions, 0 deletions
diff --git a/tests/qemu-iotests/270 b/tests/qemu-iotests/270
new file mode 100755
index 0000000000..b9a12b908c
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+++ b/tests/qemu-iotests/270
@@ -0,0 +1,83 @@
+#!/usr/bin/env bash
+#
+# Test large write to a qcow2 image
+#
+# Copyright (C) 2019 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/>.
+#
+
+seq=$(basename "$0")
+echo "QA output created by $seq"
+
+status=1	# failure is the default!
+
+_cleanup()
+{
+    _cleanup_test_img
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+# This is a qcow2 regression test
+_supported_fmt qcow2
+_supported_proto file
+_supported_os Linux
+
+# We use our own external data file and our own cluster size, and we
+# require v3 images
+_unsupported_imgopts data_file cluster_size 'compat=0.10'
+
+
+# We need a backing file so that handle_alloc_space() will not do
+# anything.  (If it were to do anything, it would simply fail its
+# write-zeroes request because the request range is too large.)
+TEST_IMG="$TEST_IMG.base" _make_test_img 4G
+$QEMU_IO -c 'write 0 512' "$TEST_IMG.base" | _filter_qemu_io
+
+# (Use .orig because _cleanup_test_img will remove that file)
+# We need a large cluster size, see below for why (above the $QEMU_IO
+# invocation)
+_make_test_img -o cluster_size=2M,data_file="$TEST_IMG.orig" \
+    -b "$TEST_IMG.base" 4G
+
+# We want a null-co as the data file, because it allows us to quickly
+# "write" 2G of data without using any space.
+# (qemu-img create does not like it, though, because null-co does not
+# support image creation.)
+$QEMU_IMG amend -o data_file="json:{'driver':'null-co',,'size':'4294967296'}" \
+    "$TEST_IMG"
+
+# This gives us a range of:
+#   2^31 - 512 + 768 - 1 = 2^31 + 255 > 2^31
+# until the beginning of the end COW block.  (The total allocation
+# size depends on the cluster size, but all that is important is that
+# it exceeds INT_MAX.)
+#
+# 2^31 - 512 is the maximum request size.  We want this to result in a
+# single allocation, and because the qcow2 driver splits allocations
+# on L2 boundaries, we need large L2 tables; hence the cluster size of
+# 2 MB.  (Anything from 256 kB should work, though, because then one L2
+# table covers 8 GB.)
+$QEMU_IO -c "write 768 $((2 ** 31 - 512))" "$TEST_IMG" | _filter_qemu_io
+
+_check_test_img
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0