iotests: Add test for checking large image files

Add a test for checking a qcow2 file with a multiple of 2^32 clusters.

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

tests/qemu-iotests/138

@@ -0,0 +1,73 @@
+#!/bin/bash
+#
+# General test case for qcow2's image check
+#
+# Copyright (C) 2015 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
+
+# This tests qocw2-specific low-level functionality
+_supported_fmt qcow2
+_supported_proto file
+_supported_os Linux
+
+echo
+echo '=== Check on an image with a multiple of 2^32 clusters ==='
+echo
+
+IMGOPTS=$(_optstr_add "$IMGOPTS" "cluster_size=512") \
+    _make_test_img 512
+
+# Allocate L2 table
+$QEMU_IO -c 'write 0 512' "$TEST_IMG" | _filter_qemu_io
+
+# Put the data cluster at a multiple of 2 TB, resulting in the image apparently
+# having a multiple of 2^32 clusters
+# (To be more specific: It is at 32 PB)
+poke_file "$TEST_IMG" 2048 "\x80\x80\x00\x00\x00\x00\x00\x00"
+
+# An offset of 32 PB results in qemu-img check having to allocate an in-memory
+# refcount table of 128 TB (16 bit refcounts, 512 byte clusters).
+# This should be generally too much for any system and thus fail.
+# What this test is checking is that the qcow2 driver actually tries to allocate
+# such a large amount of memory (and is consequently aborting) instead of having
+# truncated the cluster count somewhere (which would result in much less memory
+# being allocated and then a segfault occurring).
+_check_test_img
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0

tests/qemu-iotests/138.out

@@ -0,0 +1,9 @@
+QA output created by 138
+
+=== Check on an image with a multiple of 2^32 clusters ===
+
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=512
+wrote 512/512 bytes at offset 0
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-img: Check failed: Cannot allocate memory
+*** done

tests/qemu-iotests/group

@@ -135,3 +135,4 @@
 134 rw auto quick
 135 rw auto
 137 rw auto
+138 rw auto quick