block: Mark bdrv_replace_node() GRAPH_WRLOCK

Instead of taking the writer lock internally, require callers to already
hold it when calling bdrv_replace_node(). Its callers may already want
to hold the graph lock and so wouldn't be able to call functions that
take it internally.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20231027155333.420094-17-kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

2 files changed, 17 insertions, 2 deletions

diff --git a/tests/unit/test-bdrv-drain.c b/tests/unit/test-bdrv-drain.c
index 40d17b4c5a..b16f831c23 100644
--- a/tests/unit/test-bdrv-drain.c
+++ b/tests/unit/test-bdrv-drain.c
@@ -2000,7 +2000,13 @@ static void do_test_replace_child_mid_drain(int old_drain_count,
     parent_s->was_undrained = false;
 
     g_assert(parent_bs->quiesce_counter == old_drain_count);
+    bdrv_drained_begin(old_child_bs);
+    bdrv_drained_begin(new_child_bs);
+    bdrv_graph_wrlock(NULL);
     bdrv_replace_node(old_child_bs, new_child_bs, &error_abort);
+    bdrv_graph_wrunlock();
+    bdrv_drained_end(new_child_bs);
+    bdrv_drained_end(old_child_bs);
     g_assert(parent_bs->quiesce_counter == new_drain_count);
 
     if (!old_drain_count && !new_drain_count) {
diff --git a/tests/unit/test-bdrv-graph-mod.c b/tests/unit/test-bdrv-graph-mod.c
index 8609f7f42b..22d4cd83f6 100644
--- a/tests/unit/test-bdrv-graph-mod.c
+++ b/tests/unit/test-bdrv-graph-mod.c
@@ -234,11 +234,16 @@ static void test_parallel_exclusive_write(void)
     BlockDriverState *fl1 = pass_through_node("fl1");
     BlockDriverState *fl2 = pass_through_node("fl2");
 
+    bdrv_drained_begin(fl1);
+    bdrv_drained_begin(fl2);
+
     /*
      * bdrv_attach_child() eats child bs reference, so we need two @base
-     * references for two filters:
+     * references for two filters. We also need an additional @fl1 reference so
+     * that it still exists when we want to undrain it.
      */
     bdrv_ref(base);
+    bdrv_ref(fl1);
 
     bdrv_graph_wrlock(NULL);
     bdrv_attach_child(top, fl1, "backing", &child_of_bds,
@@ -250,10 +255,14 @@ static void test_parallel_exclusive_write(void)
     bdrv_attach_child(fl2, base, "backing", &child_of_bds,
                       BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
                       &error_abort);
-    bdrv_graph_wrunlock();
 
     bdrv_replace_node(fl1, fl2, &error_abort);
+    bdrv_graph_wrunlock();
+
+    bdrv_drained_end(fl2);
+    bdrv_drained_end(fl1);
 
+    bdrv_unref(fl1);
     bdrv_unref(fl2);
     bdrv_unref(top);
 }