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[PATCH 02/21] tests/test-bdrv-graph-mod: add test_parallel_perm_update
From: |
Vladimir Sementsov-Ogievskiy |
Subject: |
[PATCH 02/21] tests/test-bdrv-graph-mod: add test_parallel_perm_update |
Date: |
Mon, 23 Nov 2020 23:12:14 +0300 |
Add test to show that simple DFS recursion order is not correct for
permission update. Correct order is topological-sort order, which will
be introduced later.
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.
If permission update (remember, it's DFS) 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.
Now test fails, so it runs only with -d flag. To run do
./test-bdrv-graph-mod -d -p /bdrv-graph-mod/parallel-perm-update
from <build-directory>/tests.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
tests/test-bdrv-graph-mod.c | 64 +++++++++++++++++++++++++++++++++++++
1 file changed, 64 insertions(+)
diff --git a/tests/test-bdrv-graph-mod.c b/tests/test-bdrv-graph-mod.c
index 3b9e6f242f..27e3361a60 100644
--- a/tests/test-bdrv-graph-mod.c
+++ b/tests/test-bdrv-graph-mod.c
@@ -232,6 +232,68 @@ static void test_parallel_exclusive_write(void)
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,
+};
+
+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(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);
+ bdrv_ref(base);
+
+ /* 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);
+
+ /* 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);
+
+ /* 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);
+}
+
int main(int argc, char *argv[])
{
int i;
@@ -256,6 +318,8 @@ int main(int argc, char *argv[])
if (debug) {
g_test_add_func("/bdrv-graph-mod/parallel-exclusive-write",
test_parallel_exclusive_write);
+ g_test_add_func("/bdrv-graph-mod/parallel-perm-update",
+ test_parallel_perm_update);
}
return g_test_run();
--
2.21.3
- [PATCH RFC 00/21] block: update graph permissions update, Vladimir Sementsov-Ogievskiy, 2020/11/23
- [PATCH 1/2] block: make bdrv_drop_intermediate() less wrong, Vladimir Sementsov-Ogievskiy, 2020/11/23
- [PATCH 01/21] tests/test-bdrv-graph-mod: add test_parallel_exclusive_write, Vladimir Sementsov-Ogievskiy, 2020/11/23
- [PATCH 2/2] block: assert that permission commit sets same permissions, Vladimir Sementsov-Ogievskiy, 2020/11/23
- [PATCH 02/21] tests/test-bdrv-graph-mod: add test_parallel_perm_update,
Vladimir Sementsov-Ogievskiy <=
- [PATCH 03/21] util: add transactions.c, Vladimir Sementsov-Ogievskiy, 2020/11/23
- [PATCH 04/21] block: bdrv_refresh_perms: check parents compliance, Vladimir Sementsov-Ogievskiy, 2020/11/23
- [PATCH 06/21] block: rewrite bdrv_child_try_set_perm() using bdrv_refresh_perms(), Vladimir Sementsov-Ogievskiy, 2020/11/23
- [PATCH 07/21] block: inline bdrv_child_*() permission functions calls, Vladimir Sementsov-Ogievskiy, 2020/11/23
- [PATCH 08/21] block: use topological sort for permission update, Vladimir Sementsov-Ogievskiy, 2020/11/23
- [PATCH 05/21] block: refactor bdrv_child* permission functions, Vladimir Sementsov-Ogievskiy, 2020/11/23
- [PATCH 09/21] block: add bdrv_drv_set_perm transaction action, Vladimir Sementsov-Ogievskiy, 2020/11/23
- [PATCH 10/21] block: add bdrv_list_* permission update functions, Vladimir Sementsov-Ogievskiy, 2020/11/23
- [PATCH 11/21] block: add bdrv_replace_child_safe() transaction action, Vladimir Sementsov-Ogievskiy, 2020/11/23