1 /* 2 * Block node graph modifications tests 3 * 4 * Copyright (c) 2019 Virtuozzo International GmbH. All rights reserved. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program. If not, see <http://www.gnu.org/licenses/>. 18 * 19 */ 20 21 #include "qemu/osdep.h" 22 #include "qapi/error.h" 23 #include "qemu/main-loop.h" 24 #include "block/block_int.h" 25 #include "sysemu/block-backend.h" 26 27 static BlockDriver bdrv_pass_through = { 28 .format_name = "pass-through", 29 .bdrv_child_perm = bdrv_default_perms, 30 }; 31 32 static void no_perm_default_perms(BlockDriverState *bs, BdrvChild *c, 33 BdrvChildRole role, 34 BlockReopenQueue *reopen_queue, 35 uint64_t perm, uint64_t shared, 36 uint64_t *nperm, uint64_t *nshared) 37 { 38 *nperm = 0; 39 *nshared = BLK_PERM_ALL; 40 } 41 42 static BlockDriver bdrv_no_perm = { 43 .format_name = "no-perm", 44 .bdrv_child_perm = no_perm_default_perms, 45 }; 46 47 static BlockDriverState *no_perm_node(const char *name) 48 { 49 return bdrv_new_open_driver(&bdrv_no_perm, name, BDRV_O_RDWR, &error_abort); 50 } 51 52 static BlockDriverState *pass_through_node(const char *name) 53 { 54 return bdrv_new_open_driver(&bdrv_pass_through, name, 55 BDRV_O_RDWR, &error_abort); 56 } 57 58 /* 59 * test_update_perm_tree 60 * 61 * When checking node for a possibility to update permissions, it's subtree 62 * should be correctly checked too. New permissions for each node should be 63 * calculated and checked in context of permissions of other nodes. If we 64 * check new permissions of the node only in context of old permissions of 65 * its neighbors, we can finish up with wrong permission graph. 66 * 67 * This test firstly create the following graph: 68 * +--------+ 69 * | root | 70 * +--------+ 71 * | 72 * | perm: write, read 73 * | shared: except write 74 * v 75 * +-------------------+ +----------------+ 76 * | passtrough filter |---------->| null-co node | 77 * +-------------------+ +----------------+ 78 * 79 * 80 * and then, tries to append filter under node. Expected behavior: fail. 81 * Otherwise we'll get the following picture, with two BdrvChild'ren, having 82 * write permission to one node, without actually sharing it. 83 * 84 * +--------+ 85 * | root | 86 * +--------+ 87 * | 88 * | perm: write, read 89 * | shared: except write 90 * v 91 * +-------------------+ 92 * | passtrough filter | 93 * +-------------------+ 94 * | | 95 * perm: write, read | | perm: write, read 96 * shared: except write | | shared: except write 97 * v v 98 * +----------------+ 99 * | null co node | 100 * +----------------+ 101 */ 102 static void test_update_perm_tree(void) 103 { 104 int ret; 105 106 BlockBackend *root = blk_new(qemu_get_aio_context(), 107 BLK_PERM_WRITE | BLK_PERM_CONSISTENT_READ, 108 BLK_PERM_ALL & ~BLK_PERM_WRITE); 109 BlockDriverState *bs = no_perm_node("node"); 110 BlockDriverState *filter = pass_through_node("filter"); 111 112 blk_insert_bs(root, bs, &error_abort); 113 114 bdrv_attach_child(filter, bs, "child", &child_of_bds, 115 BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, &error_abort); 116 117 ret = bdrv_append(filter, bs, NULL); 118 g_assert_cmpint(ret, <, 0); 119 120 blk_unref(root); 121 } 122 123 /* 124 * test_should_update_child 125 * 126 * Test that bdrv_replace_node, and concretely should_update_child 127 * do the right thing, i.e. not creating loops on the graph. 128 * 129 * The test does the following: 130 * 1. initial graph: 131 * 132 * +------+ +--------+ 133 * | root | | filter | 134 * +------+ +--------+ 135 * | | 136 * root| target| 137 * v v 138 * +------+ +--------+ 139 * | node |<---------| target | 140 * +------+ backing +--------+ 141 * 142 * 2. Append @filter above @node. If should_update_child works correctly, 143 * it understands, that backing child of @target should not be updated, 144 * as it will create a loop on node graph. Resulting picture should 145 * be the left one, not the right: 146 * 147 * +------+ +------+ 148 * | root | | root | 149 * +------+ +------+ 150 * | | 151 * root| root| 152 * v v 153 * +--------+ target +--------+ target 154 * | filter |--------------+ | filter |--------------+ 155 * +--------+ | +--------+ | 156 * | | | ^ v 157 * backing| | backing| | +--------+ 158 * v v | +-----------| target | 159 * +------+ +--------+ v backing +--------+ 160 * | node |<---------| target | +------+ 161 * +------+ backing +--------+ | node | 162 * +------+ 163 * 164 * (good picture) (bad picture) 165 * 166 */ 167 static void test_should_update_child(void) 168 { 169 BlockBackend *root = blk_new(qemu_get_aio_context(), 0, BLK_PERM_ALL); 170 BlockDriverState *bs = no_perm_node("node"); 171 BlockDriverState *filter = no_perm_node("filter"); 172 BlockDriverState *target = no_perm_node("target"); 173 174 blk_insert_bs(root, bs, &error_abort); 175 176 bdrv_set_backing_hd(target, bs, &error_abort); 177 178 g_assert(target->backing->bs == bs); 179 bdrv_attach_child(filter, target, "target", &child_of_bds, 180 BDRV_CHILD_DATA, &error_abort); 181 bdrv_append(filter, bs, &error_abort); 182 g_assert(target->backing->bs == bs); 183 184 bdrv_unref(bs); 185 blk_unref(root); 186 } 187 188 int main(int argc, char *argv[]) 189 { 190 bdrv_init(); 191 qemu_init_main_loop(&error_abort); 192 193 g_test_init(&argc, &argv, NULL); 194 195 g_test_add_func("/bdrv-graph-mod/update-perm-tree", test_update_perm_tree); 196 g_test_add_func("/bdrv-graph-mod/should-update-child", 197 test_should_update_child); 198 199 return g_test_run(); 200 } 201