mirror of
https://github.com/xemu-project/xemu.git
synced 2024-12-24 21:05:19 +00:00
2272edcfff
bdrv_append is not very good for inserting filters: it does extra permission update as part of bdrv_set_backing_hd(). During this update filter may conflict with other parents of top_bs. Instead, let's first do all graph modifications and after it update permissions. append-greedy-filter test-case in test-bdrv-graph-mod is now works, so move it out of debug option. Note: bdrv_append() is still only works for backing-child based filters. It's something to improve later. Note2: we use the fact that bdrv_append() is used to append new nodes, without backing child, so we don't need frozen check and inherits_from logic from bdrv_set_backing_hd(). Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210428151804.439460-22-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
408 lines
14 KiB
C
408 lines
14 KiB
C
/*
|
|
* Block node graph modifications tests
|
|
*
|
|
* Copyright (c) 2019-2021 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 "qemu/main-loop.h"
|
|
#include "block/block_int.h"
|
|
#include "sysemu/block-backend.h"
|
|
|
|
static BlockDriver bdrv_pass_through = {
|
|
.format_name = "pass-through",
|
|
.bdrv_child_perm = bdrv_default_perms,
|
|
};
|
|
|
|
static void no_perm_default_perms(BlockDriverState *bs, BdrvChild *c,
|
|
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 void exclusive_write_perms(BlockDriverState *bs, BdrvChild *c,
|
|
BdrvChildRole role,
|
|
BlockReopenQueue *reopen_queue,
|
|
uint64_t perm, uint64_t shared,
|
|
uint64_t *nperm, uint64_t *nshared)
|
|
{
|
|
*nperm = BLK_PERM_WRITE;
|
|
*nshared = BLK_PERM_ALL & ~BLK_PERM_WRITE;
|
|
}
|
|
|
|
static BlockDriver bdrv_exclusive_writer = {
|
|
.format_name = "exclusive-writer",
|
|
.bdrv_child_perm = exclusive_write_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);
|
|
}
|
|
|
|
static BlockDriverState *exclusive_writer_node(const char *name)
|
|
{
|
|
return bdrv_new_open_driver(&bdrv_exclusive_writer, 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)
|
|
{
|
|
int ret;
|
|
|
|
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_of_bds,
|
|
BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, &error_abort);
|
|
|
|
ret = bdrv_append(filter, bs, NULL);
|
|
g_assert_cmpint(ret, <, 0);
|
|
|
|
bdrv_unref(filter);
|
|
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_of_bds,
|
|
BDRV_CHILD_DATA, &error_abort);
|
|
bdrv_append(filter, bs, &error_abort);
|
|
g_assert(target->backing->bs == bs);
|
|
|
|
bdrv_unref(filter);
|
|
bdrv_unref(bs);
|
|
blk_unref(root);
|
|
}
|
|
|
|
/*
|
|
* test_parallel_exclusive_write
|
|
*
|
|
* Check that when we replace node, old permissions of the node being removed
|
|
* doesn't break the replacement.
|
|
*/
|
|
static void test_parallel_exclusive_write(void)
|
|
{
|
|
BlockDriverState *top = exclusive_writer_node("top");
|
|
BlockDriverState *base = no_perm_node("base");
|
|
BlockDriverState *fl1 = pass_through_node("fl1");
|
|
BlockDriverState *fl2 = pass_through_node("fl2");
|
|
|
|
/*
|
|
* bdrv_attach_child() eats child bs reference, so we need two @base
|
|
* references for two filters:
|
|
*/
|
|
bdrv_ref(base);
|
|
|
|
bdrv_attach_child(top, fl1, "backing", &child_of_bds, BDRV_CHILD_DATA,
|
|
&error_abort);
|
|
bdrv_attach_child(fl1, base, "backing", &child_of_bds, BDRV_CHILD_FILTERED,
|
|
&error_abort);
|
|
bdrv_attach_child(fl2, base, "backing", &child_of_bds, BDRV_CHILD_FILTERED,
|
|
&error_abort);
|
|
|
|
bdrv_replace_node(fl1, fl2, &error_abort);
|
|
|
|
bdrv_unref(fl2);
|
|
bdrv_unref(top);
|
|
}
|
|
|
|
static void write_to_file_perms(BlockDriverState *bs, BdrvChild *c,
|
|
BdrvChildRole role,
|
|
BlockReopenQueue *reopen_queue,
|
|
uint64_t perm, uint64_t shared,
|
|
uint64_t *nperm, uint64_t *nshared)
|
|
{
|
|
if (bs->file && c == bs->file) {
|
|
*nperm = BLK_PERM_WRITE;
|
|
*nshared = BLK_PERM_ALL & ~BLK_PERM_WRITE;
|
|
} else {
|
|
*nperm = 0;
|
|
*nshared = BLK_PERM_ALL;
|
|
}
|
|
}
|
|
|
|
static BlockDriver bdrv_write_to_file = {
|
|
.format_name = "tricky-perm",
|
|
.bdrv_child_perm = write_to_file_perms,
|
|
};
|
|
|
|
|
|
/*
|
|
* The following test shows that topological-sort order is required for
|
|
* permission update, simple DFS is not enough.
|
|
*
|
|
* Consider the block driver which has two filter children: one active
|
|
* with exclusive write access and one inactive with no specific
|
|
* permissions.
|
|
*
|
|
* And, these two children has a common base child, like this:
|
|
*
|
|
* ┌─────┐ ┌──────┐
|
|
* │ fl2 │ ◀── │ top │
|
|
* └─────┘ └──────┘
|
|
* │ │
|
|
* │ │ w
|
|
* │ ▼
|
|
* │ ┌──────┐
|
|
* │ │ fl1 │
|
|
* │ └──────┘
|
|
* │ │
|
|
* │ │ w
|
|
* │ ▼
|
|
* │ ┌──────┐
|
|
* └───────▶ │ base │
|
|
* └──────┘
|
|
*
|
|
* So, exclusive write is propagated.
|
|
*
|
|
* Assume, we want to make fl2 active instead of fl1.
|
|
* So, we set some option for top driver and do permission update.
|
|
*
|
|
* With simple DFS, if permission update goes first through
|
|
* top->fl1->base branch it will succeed: it firstly drop exclusive write
|
|
* permissions and than apply them for another BdrvChildren.
|
|
* But if permission update goes first through top->fl2->base branch it
|
|
* will fail, as when we try to update fl2->base child, old not yet
|
|
* updated fl1->base child will be in conflict.
|
|
*
|
|
* With topological-sort order we always update parents before children, so fl1
|
|
* and fl2 are both updated when we update base and there is no conflict.
|
|
*/
|
|
static void test_parallel_perm_update(void)
|
|
{
|
|
BlockDriverState *top = no_perm_node("top");
|
|
BlockDriverState *tricky =
|
|
bdrv_new_open_driver(&bdrv_write_to_file, "tricky", BDRV_O_RDWR,
|
|
&error_abort);
|
|
BlockDriverState *base = no_perm_node("base");
|
|
BlockDriverState *fl1 = pass_through_node("fl1");
|
|
BlockDriverState *fl2 = pass_through_node("fl2");
|
|
BdrvChild *c_fl1, *c_fl2;
|
|
|
|
/*
|
|
* bdrv_attach_child() eats child bs reference, so we need two @base
|
|
* references for two filters:
|
|
*/
|
|
bdrv_ref(base);
|
|
|
|
bdrv_attach_child(top, tricky, "file", &child_of_bds, BDRV_CHILD_DATA,
|
|
&error_abort);
|
|
c_fl1 = bdrv_attach_child(tricky, fl1, "first", &child_of_bds,
|
|
BDRV_CHILD_FILTERED, &error_abort);
|
|
c_fl2 = bdrv_attach_child(tricky, fl2, "second", &child_of_bds,
|
|
BDRV_CHILD_FILTERED, &error_abort);
|
|
bdrv_attach_child(fl1, base, "backing", &child_of_bds, BDRV_CHILD_FILTERED,
|
|
&error_abort);
|
|
bdrv_attach_child(fl2, base, "backing", &child_of_bds, BDRV_CHILD_FILTERED,
|
|
&error_abort);
|
|
|
|
/* Select fl1 as first child to be active */
|
|
tricky->file = c_fl1;
|
|
bdrv_child_refresh_perms(top, top->children.lh_first, &error_abort);
|
|
|
|
assert(c_fl1->perm & BLK_PERM_WRITE);
|
|
assert(!(c_fl2->perm & BLK_PERM_WRITE));
|
|
|
|
/* Now, try to switch active child and update permissions */
|
|
tricky->file = c_fl2;
|
|
bdrv_child_refresh_perms(top, top->children.lh_first, &error_abort);
|
|
|
|
assert(c_fl2->perm & BLK_PERM_WRITE);
|
|
assert(!(c_fl1->perm & BLK_PERM_WRITE));
|
|
|
|
/* Switch once more, to not care about real child order in the list */
|
|
tricky->file = c_fl1;
|
|
bdrv_child_refresh_perms(top, top->children.lh_first, &error_abort);
|
|
|
|
assert(c_fl1->perm & BLK_PERM_WRITE);
|
|
assert(!(c_fl2->perm & BLK_PERM_WRITE));
|
|
|
|
bdrv_unref(top);
|
|
}
|
|
|
|
/*
|
|
* It's possible that filter required permissions allows to insert it to backing
|
|
* chain, like:
|
|
*
|
|
* 1. [top] -> [filter] -> [base]
|
|
*
|
|
* but doesn't allow to add it as a branch:
|
|
*
|
|
* 2. [filter] --\
|
|
* v
|
|
* [top] -> [base]
|
|
*
|
|
* So, inserting such filter should do all graph modifications and only then
|
|
* update permissions. If we try to go through intermediate state [2] and update
|
|
* permissions on it we'll fail.
|
|
*
|
|
* Let's check that bdrv_append() can append such a filter.
|
|
*/
|
|
static void test_append_greedy_filter(void)
|
|
{
|
|
BlockDriverState *top = exclusive_writer_node("top");
|
|
BlockDriverState *base = no_perm_node("base");
|
|
BlockDriverState *fl = exclusive_writer_node("fl1");
|
|
|
|
bdrv_attach_child(top, base, "backing", &child_of_bds, BDRV_CHILD_COW,
|
|
&error_abort);
|
|
|
|
bdrv_append(fl, base, &error_abort);
|
|
bdrv_unref(fl);
|
|
bdrv_unref(top);
|
|
}
|
|
|
|
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);
|
|
g_test_add_func("/bdrv-graph-mod/parallel-perm-update",
|
|
test_parallel_perm_update);
|
|
g_test_add_func("/bdrv-graph-mod/parallel-exclusive-write",
|
|
test_parallel_exclusive_write);
|
|
g_test_add_func("/bdrv-graph-mod/append-greedy-filter",
|
|
test_append_greedy_filter);
|
|
|
|
return g_test_run();
|
|
}
|