| /* |
| * 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", |
| .is_filter = true, |
| .filtered_child_is_backing = true, |
| .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", |
| .supports_backing = true, |
| .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", |
| .is_filter = true, |
| .filtered_child_is_backing = true, |
| .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 |
| * +--------------------+ +----------------+ |
| * | passthrough 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 |
| * +--------------------+ |
| * | passthrough 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_DATA, &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_FILTERED | BDRV_CHILD_PRIMARY, |
| &error_abort); |
| bdrv_attach_child(fl1, base, "backing", &child_of_bds, |
| BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, |
| &error_abort); |
| bdrv_attach_child(fl2, base, "backing", &child_of_bds, |
| BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, |
| &error_abort); |
| |
| bdrv_replace_node(fl1, fl2, &error_abort); |
| |
| bdrv_unref(fl2); |
| bdrv_unref(top); |
| } |
| |
| /* |
| * write-to-selected node may have several DATA children, one of them may be |
| * "selected". Exclusive write permission is taken on selected child. |
| * |
| * We don't realize write handler itself, as we need only to test how permission |
| * update works. |
| */ |
| typedef struct BDRVWriteToSelectedState { |
| BdrvChild *selected; |
| } BDRVWriteToSelectedState; |
| |
| static void write_to_selected_perms(BlockDriverState *bs, BdrvChild *c, |
| BdrvChildRole role, |
| BlockReopenQueue *reopen_queue, |
| uint64_t perm, uint64_t shared, |
| uint64_t *nperm, uint64_t *nshared) |
| { |
| BDRVWriteToSelectedState *s = bs->opaque; |
| |
| if (s->selected && c == s->selected) { |
| *nperm = BLK_PERM_WRITE; |
| *nshared = BLK_PERM_ALL & ~BLK_PERM_WRITE; |
| } else { |
| *nperm = 0; |
| *nshared = BLK_PERM_ALL; |
| } |
| } |
| |
| static BlockDriver bdrv_write_to_selected = { |
| .format_name = "write-to-selected", |
| .instance_size = sizeof(BDRVWriteToSelectedState), |
| .bdrv_child_perm = write_to_selected_perms, |
| }; |
| |
| |
| /* |
| * The following test shows that topological-sort order is required for |
| * permission update, simple DFS is not enough. |
| * |
| * Consider the block driver (write-to-selected) which has two children: one is |
| * selected so we have exclusive write access to it and for the other one we |
| * don't need any specific permissions. |
| * |
| * And, these two children has a common base child, like this: |
| * (additional "top" on top is used in test just because the only public |
| * function to update permission should get a specific child to update. |
| * Making bdrv_refresh_perms() public just for this test isn't worth it) |
| * |
| * ┌─────┐ ┌───────────────────┐ ┌─────┐ |
| * │ fl2 │ ◀── │ write-to-selected │ ◀── │ top │ |
| * └─────┘ └───────────────────┘ └─────┘ |
| * │ │ |
| * │ │ w |
| * │ ▼ |
| * │ ┌──────┐ |
| * │ │ fl1 │ |
| * │ └──────┘ |
| * │ │ |
| * │ │ w |
| * │ ▼ |
| * │ ┌──────┐ |
| * └───────▶ │ base │ |
| * └──────┘ |
| * |
| * So, exclusive write is propagated. |
| * |
| * Assume, we want to select fl2 instead of fl1. |
| * So, we set some option for write-to-selected driver and do permission update. |
| * |
| * With simple DFS, if permission update goes first through |
| * write-to-selected -> 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 write-to-selected -> 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 *ws = |
| bdrv_new_open_driver(&bdrv_write_to_selected, "ws", BDRV_O_RDWR, |
| &error_abort); |
| BDRVWriteToSelectedState *s = ws->opaque; |
| 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, ws, "file", &child_of_bds, BDRV_CHILD_DATA, |
| &error_abort); |
| c_fl1 = bdrv_attach_child(ws, fl1, "first", &child_of_bds, |
| BDRV_CHILD_DATA, &error_abort); |
| c_fl2 = bdrv_attach_child(ws, fl2, "second", &child_of_bds, |
| BDRV_CHILD_DATA, &error_abort); |
| bdrv_attach_child(fl1, base, "backing", &child_of_bds, |
| BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, |
| &error_abort); |
| bdrv_attach_child(fl2, base, "backing", &child_of_bds, |
| BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, |
| &error_abort); |
| |
| /* Select fl1 as first child to be active */ |
| s->selected = 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 */ |
| s->selected = 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 */ |
| s->selected = 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_FILTERED | BDRV_CHILD_PRIMARY, |
| &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(); |
| } |
