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[PATCH v2 19/36] block: fix bdrv_replace_node_common
From: |
Vladimir Sementsov-Ogievskiy |
Subject: |
[PATCH v2 19/36] block: fix bdrv_replace_node_common |
Date: |
Fri, 27 Nov 2020 17:45:05 +0300 |
inore_children thing doesn't help to track all propagated permissions
of children we want to ignore. The simplest way to correctly update
permissions is update graph first and then do permission update. In
this case we just referesh permissions for the whole subgraph (in
topological-sort defined order) and everything is correctly calculated
automatically without any ignore_children.
So, refactor bdrv_replace_node_common to first do graph update and then
refresh the permissions.
Test test_parallel_exclusive_write() now pass, so move it out of
debugging "if".
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
block.c | 42 ++++++++++++++-----------------------
tests/test-bdrv-graph-mod.c | 18 +++-------------
2 files changed, 19 insertions(+), 41 deletions(-)
diff --git a/block.c b/block.c
index f24bd60c2f..f0fcd75555 100644
--- a/block.c
+++ b/block.c
@@ -2199,7 +2199,6 @@ static TransactionActionDrv bdrv_replace_child_drv = {
*
* Note: real unref of old_bs is done only on commit.
*/
-__attribute__((unused))
static void bdrv_replace_child_safe(BdrvChild *child, BlockDriverState *new_bs,
GSList **tran)
{
@@ -4794,8 +4793,9 @@ static int bdrv_replace_node_common(BlockDriverState
*from,
{
int ret = -EPERM;
BdrvChild *c, *next;
- GSList *list = NULL, *p;
- uint64_t perm = 0, shared = BLK_PERM_ALL;
+ GSList *tran = NULL;
+ g_autoptr(GHashTable) found = NULL;
+ g_autoptr(GSList) refresh_list = NULL;
/* Make sure that @from doesn't go away until we have successfully attached
* all of its parents to @to. */
@@ -4805,7 +4805,12 @@ static int bdrv_replace_node_common(BlockDriverState
*from,
assert(bdrv_get_aio_context(from) == bdrv_get_aio_context(to));
bdrv_drained_begin(from);
- /* Put all parents into @list and calculate their cumulative permissions */
+ /*
+ * Do the replacement without permission update.
+ * Replacement may influence the permissions, we should calculate new
+ * permissions based on new graph. If we fail, we'll roll-back the
+ * replacement.
+ */
QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) {
assert(c->bs == from);
if (!should_update_child(c, to)) {
@@ -4821,34 +4826,19 @@ static int bdrv_replace_node_common(BlockDriverState
*from,
c->name, from->node_name);
goto out;
}
- list = g_slist_prepend(list, c);
- perm |= c->perm;
- shared &= c->shared_perm;
- }
-
- /* Check whether the required permissions can be granted on @to, ignoring
- * all BdrvChild in @list so that they can't block themselves. */
- ret = bdrv_check_update_perm(to, NULL, perm, shared, list, errp);
- if (ret < 0) {
- bdrv_abort_perm_update(to);
- goto out;
+ bdrv_replace_child_safe(c, to, &tran);
}
- /* Now actually perform the change. We performed the permission check for
- * all elements of @list at once, so set the permissions all at once at the
- * very end. */
- for (p = list; p != NULL; p = p->next) {
- c = p->data;
+ found = g_hash_table_new(NULL, NULL);
- bdrv_ref(to);
- bdrv_replace_child_noperm(c, to);
- bdrv_unref(from);
- }
+ refresh_list = bdrv_topological_dfs(refresh_list, found, to);
+ refresh_list = bdrv_topological_dfs(refresh_list, found, from);
- bdrv_set_perm(to);
+ ret = bdrv_list_refresh_perms(refresh_list, NULL, &tran, errp);
out:
- g_slist_free(list);
+ tran_finalize(tran, ret);
+
bdrv_drained_end(from);
bdrv_unref(from);
diff --git a/tests/test-bdrv-graph-mod.c b/tests/test-bdrv-graph-mod.c
index 0d62e05ddb..93a5941a9b 100644
--- a/tests/test-bdrv-graph-mod.c
+++ b/tests/test-bdrv-graph-mod.c
@@ -294,20 +294,11 @@ static void test_parallel_perm_update(void)
bdrv_child_refresh_perms(top, top->children.lh_first, &error_abort);
assert(c_fl1->perm & BLK_PERM_WRITE);
+ bdrv_unref(top);
}
int main(int argc, char *argv[])
{
- int i;
- bool debug = false;
-
- for (i = 1; i < argc; i++) {
- if (!strcmp(argv[i], "-d")) {
- debug = true;
- break;
- }
- }
-
bdrv_init();
qemu_init_main_loop(&error_abort);
@@ -318,11 +309,8 @@ int main(int argc, char *argv[])
test_should_update_child);
g_test_add_func("/bdrv-graph-mod/parallel-perm-update",
test_parallel_perm_update);
-
- if (debug) {
- g_test_add_func("/bdrv-graph-mod/parallel-exclusive-write",
- test_parallel_exclusive_write);
- }
+ g_test_add_func("/bdrv-graph-mod/parallel-exclusive-write",
+ test_parallel_exclusive_write);
return g_test_run();
}
--
2.21.3
- [PATCH v2 01/36] tests/test-bdrv-graph-mod: add test_parallel_exclusive_write, (continued)
- [PATCH v2 01/36] tests/test-bdrv-graph-mod: add test_parallel_exclusive_write, Vladimir Sementsov-Ogievskiy, 2020/11/27
- [PATCH v2 07/36] block: drop ctx argument from bdrv_root_attach_child, Vladimir Sementsov-Ogievskiy, 2020/11/27
- [PATCH v2 06/36] block: BdrvChildClass: add .get_parent_aio_context handler, Vladimir Sementsov-Ogievskiy, 2020/11/27
- [PATCH v2 08/36] block: make bdrv_reopen_{prepare, commit, abort} private, Vladimir Sementsov-Ogievskiy, 2020/11/27
- [PATCH v2 09/36] block: return value from bdrv_replace_node(), Vladimir Sementsov-Ogievskiy, 2020/11/27
- [PATCH v2 12/36] block: refactor bdrv_child* permission functions, Vladimir Sementsov-Ogievskiy, 2020/11/27
- [PATCH v2 16/36] block: add bdrv_drv_set_perm transaction action, Vladimir Sementsov-Ogievskiy, 2020/11/27
- [PATCH v2 13/36] block: rewrite bdrv_child_try_set_perm() using bdrv_refresh_perms(), Vladimir Sementsov-Ogievskiy, 2020/11/27
- [PATCH v2 10/36] util: add transactions.c, Vladimir Sementsov-Ogievskiy, 2020/11/27
- [PATCH v2 11/36] block: bdrv_refresh_perms: check parents compliance, Vladimir Sementsov-Ogievskiy, 2020/11/27
- [PATCH v2 19/36] block: fix bdrv_replace_node_common,
Vladimir Sementsov-Ogievskiy <=
- [PATCH v2 15/36] block: use topological sort for permission update, Vladimir Sementsov-Ogievskiy, 2020/11/27
- [PATCH v2 18/36] block: add bdrv_replace_child_safe() transaction action, Vladimir Sementsov-Ogievskiy, 2020/11/27
- [PATCH v2 20/36] block: add bdrv_attach_child_common() transaction action, Vladimir Sementsov-Ogievskiy, 2020/11/27
- [PATCH v2 24/36] block: add bdrv_remove_backing transaction action, Vladimir Sementsov-Ogievskiy, 2020/11/27
- [PATCH v2 14/36] block: inline bdrv_child_*() permission functions calls, Vladimir Sementsov-Ogievskiy, 2020/11/27
- [PATCH v2 27/36] block: drop ignore_children for permission update functions, Vladimir Sementsov-Ogievskiy, 2020/11/27
- [PATCH v2 02/36] tests/test-bdrv-graph-mod: add test_parallel_perm_update, Vladimir Sementsov-Ogievskiy, 2020/11/27
- [PATCH v2 17/36] block: add bdrv_list_* permission update functions, Vladimir Sementsov-Ogievskiy, 2020/11/27
- [PATCH v2 21/36] block: add bdrv_attach_child_noperm() transaction action, Vladimir Sementsov-Ogievskiy, 2020/11/27
- [PATCH v2 26/36] block/backup-top: drop .active, Vladimir Sementsov-Ogievskiy, 2020/11/27