On 30.03.22 23:28, Vladimir Sementsov-Ogievskiy wrote:
test_parallel_perm_update() does two things that we are going to
restrict in the near future:
1. It updates bs->file field by hand. bs->file will be managed
automatically by generic code (together with bs->children list).
Let's better refactor our "tricky" bds to have own state where one
of children is linked as "selected".
This also looks less "tricky", so avoid using this word.
2. It create FILTERED children that are not PRIMARY. Except for tests
all FILTERED children in the Qemu block layer are always PRIMARY as
well. We are going to formalize this rule, so let's better use DATA
children here.
Another thing is that any node may have at most one FILTERED child at a time,
which was already formalized in BDRV_CHILD_FILTERED’s description.
While being here, update the picture to better correspond to the test
code.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@openvz.org>
---
The change looks good, I’m just a bit confused when it comes to the comment
describing what’s going on.
tests/unit/test-bdrv-graph-mod.c | 70 ++++++++++++++++++++------------
1 file changed, 44 insertions(+), 26 deletions(-)
diff --git a/tests/unit/test-bdrv-graph-mod.c b/tests/unit/test-bdrv-graph-mod.c
index a6e3bb79be..40795d3c04 100644
--- a/tests/unit/test-bdrv-graph-mod.c
+++ b/tests/unit/test-bdrv-graph-mod.c
[...]
@@ -266,15 +280,18 @@ static BlockDriver bdrv_write_to_file = {
* 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.
+ * 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 doesn't worth it)
s/doesn't/isn't/
*
- * ┌─────┐ ┌──────┐
- * │ fl2 │ ◀── │ top │
- * └─────┘ └──────┘
+ * ┌─────┐ ┌───────────────────┐ ┌─────┐
+ * │ fl2 │ ◀── │ write-to-selected │ ◀── │ top │
+ * └─────┘ └───────────────────┘ └─────┘
* │ │
* │ │ w
* │ ▼
@@ -290,7 +307,7 @@ static BlockDriver bdrv_write_to_file = {
*
* So, exclusive write is propagated.
*
- * Assume, we want to make fl2 active instead of fl1.
+ * Assume, we want to select fl2 instead of fl1.
There’s a double space after “fl2”.
* So, we set some option for top driver and do permission update.
Here and in the rest of the comment, it’s now unclear what node “top” refers
to. I think it’s still the now-renamed “write-to-selected” node, right? But
“top” is now a different node, so I’m not 100% sure.