xref: /openbmc/qemu/tests/qemu-iotests/270 (revision 812b31d3)
1#!/usr/bin/env bash
2# group: rw backing quick
3#
4# Test large write to a qcow2 image
5#
6# Copyright (C) 2019 Red Hat, Inc.
7#
8# This program is free software; you can redistribute it and/or modify
9# it under the terms of the GNU General Public License as published by
10# the Free Software Foundation; either version 2 of the License, or
11# (at your option) any later version.
12#
13# This program is distributed in the hope that it will be useful,
14# but WITHOUT ANY WARRANTY; without even the implied warranty of
15# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16# GNU General Public License for more details.
17#
18# You should have received a copy of the GNU General Public License
19# along with this program.  If not, see <http://www.gnu.org/licenses/>.
20#
21
22seq=$(basename "$0")
23echo "QA output created by $seq"
24
25status=1	# failure is the default!
26
27_cleanup()
28{
29    _cleanup_test_img
30}
31trap "_cleanup; exit \$status" 0 1 2 3 15
32
33# get standard environment, filters and checks
34. ./common.rc
35. ./common.filter
36
37# This is a qcow2 regression test
38_supported_fmt qcow2
39_supported_proto file
40_supported_os Linux
41
42# We use our own external data file and our own cluster size, and we
43# require v3 images
44_unsupported_imgopts data_file cluster_size 'compat=0.10'
45
46
47# We need a backing file so that handle_alloc_space() will not do
48# anything.  (If it were to do anything, it would simply fail its
49# write-zeroes request because the request range is too large.)
50TEST_IMG="$TEST_IMG.base" _make_test_img 4G
51$QEMU_IO -c 'write 0 512' "$TEST_IMG.base" | _filter_qemu_io
52
53# (Use .orig because _cleanup_test_img will remove that file)
54# We need a large cluster size, see below for why (above the $QEMU_IO
55# invocation)
56_make_test_img -o cluster_size=2M,data_file="$TEST_IMG.orig" \
57    -b "$TEST_IMG.base" -F $IMGFMT 4G
58
59# We want a null-co as the data file, because it allows us to quickly
60# "write" 2G of data without using any space.
61# (qemu-img create does not like it, though, because null-co does not
62# support image creation.)
63$QEMU_IMG amend -o data_file="json:{'driver':'null-co',,'size':'4294967296'}" \
64    "$TEST_IMG"
65
66# This gives us a range of:
67#   2^31 - 512 + 768 - 1 = 2^31 + 255 > 2^31
68# until the beginning of the end COW block.  (The total allocation
69# size depends on the cluster size, but all that is important is that
70# it exceeds INT_MAX.)
71#
72# 2^31 - 512 is the maximum request size.  We want this to result in a
73# single allocation, and because the qcow2 driver splits allocations
74# on L2 boundaries, we need large L2 tables; hence the cluster size of
75# 2 MB.  (Anything from 256 kB should work, though, because then one L2
76# table covers 8 GB.)
77$QEMU_IO -c "write 768 $((2 ** 31 - 512))" "$TEST_IMG" | _filter_qemu_io
78
79_check_test_img
80
81# success, all done
82echo "*** done"
83rm -f $seq.full
84status=0
85