xref: /qemu/tests/qemu-iotests/125 (revision abff1abf) 
1#!/usr/bin/env bash
2#
3# Test preallocated growth of qcow2 images
4#
5# Copyright (C) 2017 Red Hat, Inc.
6#
7# This program is free software; you can redistribute it and/or modify
8# it under the terms of the GNU General Public License as published by
9# the Free Software Foundation; either version 2 of the License, or
10# (at your option) any later version.
11#
12# This program is distributed in the hope that it will be useful,
13# but WITHOUT ANY WARRANTY; without even the implied warranty of
14# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15# GNU General Public License for more details.
16#
17# You should have received a copy of the GNU General Public License
18# along with this program.  If not, see <http://www.gnu.org/licenses/>.
19#
20
21# creator
22owner=mreitz@redhat.com
23
24seq=$(basename $0)
25echo "QA output created by $seq"
26
27status=1	# failure is the default!
28
29_cleanup()
30{
31	_cleanup_test_img
32}
33trap "_cleanup; exit \$status" 0 1 2 3 15
34
35get_image_size_on_host()
36{
37    echo $(($(stat -c '%b * %B' "$TEST_IMG_FILE")))
38}
39
40# get standard environment and filters
41. ./common.rc
42. ./common.filter
43
44_supported_fmt qcow2
45_supported_proto file
46
47if [ -z "$TEST_IMG_FILE" ]; then
48    TEST_IMG_FILE=$TEST_IMG
49fi
50
51# Test whether we are running on a broken XFS version.  There is this
52# bug:
53
54# $ rm -f foo
55# $ touch foo
56# $ block_size=4096 # Your FS's block size
57# $ fallocate -o $((block_size / 2)) -l $block_size foo
58# $ LANG=C xfs_bmap foo | grep hole
59#         1: [8..15]: hole
60#
61# The problem is that the XFS driver rounds down the offset and
62# rounds up the length to the block size, but independently.  As
63# such, it only allocates the first block in the example above,
64# even though it should allocate the first two blocks (because our
65# request is to fallocate something that touches both the first
66# two blocks).
67#
68# This means that when you then write to the beginning of the
69# second block, the disk usage of the first two blocks grows.
70#
71# That is precisely what fallocate() promises, though: That when you
72# write to an area that you have fallocated, no new blocks will have
73# to be allocated.
74
75touch "$TEST_IMG_FILE"
76# Assuming there is no FS with a block size greater than 64k
77fallocate -o 65535 -l 2 "$TEST_IMG_FILE"
78len0=$(get_image_size_on_host)
79
80# Write to something that in theory we have just fallocated
81# (Thus, the on-disk size should not increase)
82poke_file "$TEST_IMG_FILE" 65536 42
83len1=$(get_image_size_on_host)
84
85if [ $len1 -gt $len0 ]; then
86    _notrun "the test filesystem's fallocate() is broken"
87fi
88
89rm -f "$TEST_IMG_FILE"
90
91# Generally, we create some image with or without existing preallocation and
92# then resize it. Then we write some data into the image and verify that its
93# size does not change if we have used preallocation.
94
95# With a cluster size of 512 B, one L2 table covers 64 * 512 B = 32 kB.
96# One cluster of the L1 table covers 64 * 32 kB = 2 MB.
97# There are multiple cases we want to test:
98# (1) Grow an image without having to allocate a new L2 table.
99# (2) Grow an image, having to allocate a new L2 table.
100# (3) Grow an image, having to grow the L1 table.
101# Therefore, we create an image that is 48 kB below 2 MB. Then:
102# (1) We resize it to 2 MB - 32 kB. (+ 16 kB)
103# (2) We resize it to 2 MB.         (+ 48 kB)
104# (3) We resize it to 2 MB + 32 kB. (+ 80 kB)
105
106# in B
107CREATION_SIZE=$((2 * 1024 * 1024 - 48 * 1024))
108
109# 512 is the actual test -- but it's good to test 64k as well, just to be sure.
110for cluster_size in 512 64k; do
111# in kB
112for GROWTH_SIZE in 16 48 80; do
113    for create_mode in off metadata falloc full; do
114        for growth_mode in off metadata falloc full; do
115            echo "--- cluster_size=$cluster_size growth_size=$GROWTH_SIZE create_mode=$create_mode growth_mode=$growth_mode ---"
116
117            _make_test_img -o "preallocation=$create_mode,cluster_size=$cluster_size" ${CREATION_SIZE}
118            $QEMU_IMG resize -f "$IMGFMT" --preallocation=$growth_mode "$TEST_IMG" +${GROWTH_SIZE}K
119
120            host_size_0=$(get_image_size_on_host)
121            file_length_0=$(stat -c '%s' "$TEST_IMG_FILE")
122
123            $QEMU_IO -c "write 0 $CREATION_SIZE" "$TEST_IMG" | _filter_qemu_io
124
125            host_size_1=$(get_image_size_on_host)
126            file_length_1=$(stat -c '%s' "$TEST_IMG_FILE")
127
128            $QEMU_IO -c "write $CREATION_SIZE ${GROWTH_SIZE}K" "$TEST_IMG" | _filter_qemu_io
129
130            host_size_2=$(get_image_size_on_host)
131            file_length_2=$(stat -c '%s' "$TEST_IMG_FILE")
132
133            # Test creation preallocation: Compare #0 against #1
134            if [ $create_mode != off ]; then
135                # The image length should not have grown
136                if [ $file_length_1 -gt $file_length_0 ]; then
137                    echo "ERROR (create): Image length has grown from $file_length_0 to $file_length_1"
138                fi
139                if [ $create_mode != metadata ]; then
140                    # The host size should not have grown either
141                    if [ $host_size_1 -gt $host_size_0 ]; then
142                        echo "ERROR (create): Host size has grown from $host_size_0 to $host_size_1"
143                    fi
144                fi
145            fi
146
147            # Test resize preallocation: Compare #2 against #1
148            if [ $growth_mode != off ]; then
149                # The image length should not have grown
150                if [ $file_length_2 -gt $file_length_1 ]; then
151                    echo "ERROR (grow): Image length has grown from $file_length_1 to $file_length_2"
152                fi
153                if [ $growth_mode != metadata ]; then
154                    # The host size should not have grown either
155                    if [ $host_size_2 -gt $host_size_1 ]; then
156                        echo "ERROR (grow): Host size has grown from $host_size_1 to $host_size_2"
157                    fi
158                fi
159            fi
160
161            echo
162        done
163    done
164done
165done
166
167# Test image resizing using preallocation and unaligned offsets
168$QEMU_IMG create -f raw "$TEST_IMG.base" 128k | _filter_img_create
169$QEMU_IO -c 'write -q -P 1 0 128k' -f raw "$TEST_IMG.base"
170for orig_size in 31k 33k; do
171    echo "--- Resizing image from $orig_size to 96k ---"
172    _make_test_img -F raw -b "$TEST_IMG.base" -o cluster_size=64k "$orig_size"
173    $QEMU_IMG resize -f "$IMGFMT" --preallocation=full "$TEST_IMG" 96k
174    # The first part of the image should contain data from the backing file
175    $QEMU_IO -c "read -q -P 1 0 ${orig_size}" "$TEST_IMG"
176    # The resized part of the image should contain zeroes
177    $QEMU_IO -c "read -q -P 0 ${orig_size} 63k" "$TEST_IMG"
178    # If the image does not have an external data file we can also verify its
179    # actual size. The resized image should have 7 clusters:
180    # header, L1 table, L2 table, refcount table, refcount block, 2 data clusters
181    if ! _get_data_file "$TEST_IMG" > /dev/null; then
182        expected_file_length=$((65536 * 7))
183        file_length=$(stat -c '%s' "$TEST_IMG_FILE")
184        if [ "$file_length" != "$expected_file_length" ]; then
185            echo "ERROR: file length $file_length (expected $expected_file_length)"
186        fi
187    fi
188    echo
189done
190
191# success, all done
192echo '*** done'
193rm -f $seq.full
194status=0
195