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/*
* Block node graph modifications tests
*
* Copyright (c) 2019 Virtuozzo International GmbH. All rights reserved.
*
* 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/>.
*
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "block/block_int.h"
#include "sysemu/block-backend.h"
static BlockDriver bdrv_pass_through = {
.format_name = "pass-through",
.bdrv_child_perm = bdrv_filter_default_perms,
};
static void no_perm_default_perms(BlockDriverState *bs, BdrvChild *c,
const BdrvChildRole *role,
BlockReopenQueue *reopen_queue,
uint64_t perm, uint64_t shared,
uint64_t *nperm, uint64_t *nshared)
{
*nperm = 0;
*nshared = BLK_PERM_ALL;
}
static BlockDriver bdrv_no_perm = {
.format_name = "no-perm",
.bdrv_child_perm = no_perm_default_perms,
};
static BlockDriverState *no_perm_node(const char *name)
{
return bdrv_new_open_driver(&bdrv_no_perm, name, BDRV_O_RDWR, &error_abort);
}
static BlockDriverState *pass_through_node(const char *name)
{
return bdrv_new_open_driver(&bdrv_pass_through, name,
BDRV_O_RDWR, &error_abort);
}
/*
* test_update_perm_tree
*
* When checking node for a possibility to update permissions, it's subtree
* should be correctly checked too. New permissions for each node should be
* calculated and checked in context of permissions of other nodes. If we
* check new permissions of the node only in context of old permissions of
* its neighbors, we can finish up with wrong permission graph.
*
* This test firstly create the following graph:
* +--------+
* | root |
* +--------+
* |
* | perm: write, read
* | shared: except write
* v
* +-------------------+ +----------------+
* | passtrough filter |---------->| null-co node |
* +-------------------+ +----------------+
*
*
* and then, tries to append filter under node. Expected behavior: fail.
* Otherwise we'll get the following picture, with two BdrvChild'ren, having
* write permission to one node, without actually sharing it.
*
* +--------+
* | root |
* +--------+
* |
* | perm: write, read
* | shared: except write
* v
* +-------------------+
* | passtrough filter |
* +-------------------+
* | |
* perm: write, read | | perm: write, read
* shared: except write | | shared: except write
* v v
* +----------------+
* | null co node |
* +----------------+
*/
static void test_update_perm_tree(void)
{
Error *local_err = NULL;
BlockBackend *root = blk_new(qemu_get_aio_context(),
BLK_PERM_WRITE | BLK_PERM_CONSISTENT_READ,
BLK_PERM_ALL & ~BLK_PERM_WRITE);
BlockDriverState *bs = no_perm_node("node");
BlockDriverState *filter = pass_through_node("filter");
blk_insert_bs(root, bs, &error_abort);
bdrv_attach_child(filter, bs, "child", &child_file, &error_abort);
bdrv_append(filter, bs, &local_err);
g_assert_nonnull(local_err);
error_free(local_err);
blk_unref(root);
}
/*
* test_should_update_child
*
* Test that bdrv_replace_node, and concretely should_update_child
* do the right thing, i.e. not creating loops on the graph.
*
* The test does the following:
* 1. initial graph:
*
* +------+ +--------+
* | root | | filter |
* +------+ +--------+
* | |
* root| target|
* v v
* +------+ +--------+
* | node |<---------| target |
* +------+ backing +--------+
*
* 2. Append @filter above @node. If should_update_child works correctly,
* it understands, that backing child of @target should not be updated,
* as it will create a loop on node graph. Resulting picture should
* be the left one, not the right:
*
* +------+ +------+
* | root | | root |
* +------+ +------+
* | |
* root| root|
* v v
* +--------+ target +--------+ target
* | filter |--------------+ | filter |--------------+
* +--------+ | +--------+ |
* | | | ^ v
* backing| | backing| | +--------+
* v v | +-----------| target |
* +------+ +--------+ v backing +--------+
* | node |<---------| target | +------+
* +------+ backing +--------+ | node |
* +------+
*
* (good picture) (bad picture)
*
*/
static void test_should_update_child(void)
{
BlockBackend *root = blk_new(qemu_get_aio_context(), 0, BLK_PERM_ALL);
BlockDriverState *bs = no_perm_node("node");
BlockDriverState *filter = no_perm_node("filter");
BlockDriverState *target = no_perm_node("target");
blk_insert_bs(root, bs, &error_abort);
bdrv_set_backing_hd(target, bs, &error_abort);
g_assert(target->backing->bs == bs);
bdrv_attach_child(filter, target, "target", &child_file, &error_abort);
bdrv_append(filter, bs, &error_abort);
g_assert(target->backing->bs == bs);
bdrv_unref(bs);
blk_unref(root);
}
int main(int argc, char *argv[])
{
bdrv_init();
qemu_init_main_loop(&error_abort);
g_test_init(&argc, &argv, NULL);
g_test_add_func("/bdrv-graph-mod/update-perm-tree", test_update_perm_tree);
g_test_add_func("/bdrv-graph-mod/should-update-child",
test_should_update_child);
return g_test_run();
}
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