Merge tag 'for-upstream' of https://repo.or.cz/qemu/kevin into staging

Block layer patches

- Code cleanups around block graph modification
- Simplify drain
- coroutine_fn correctness fixes, including splitting generated
  coroutine wrappers into co_wrapper (to be called only from
  non-coroutine context) and co_wrapper_mixed (both coroutine and
  non-coroutine context)
- Introduce a block graph rwlock

# gpg: Signature made Thu 15 Dec 2022 15:08:34 GMT
# gpg:                using RSA key DC3DEB159A9AF95D3D7456FE7F09B272C88F2FD6
# gpg:                issuer "kwolf@redhat.com"
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* tag 'for-upstream' of https://repo.or.cz/qemu/kevin: (50 commits)
  block: GRAPH_RDLOCK for functions only called by co_wrappers
  block: use co_wrapper_mixed_bdrv_rdlock in functions taking the rdlock
  block-coroutine-wrapper.py: introduce annotations that take the graph rdlock
  Mark assert_bdrv_graph_readable/writable() GRAPH_RD/WRLOCK
  graph-lock: TSA annotations for lock/unlock functions
  block: assert that graph read and writes are performed correctly
  block: remove unnecessary assert_bdrv_graph_writable()
  block: wrlock in bdrv_replace_child_noperm
  block: Fix locking in external_snapshot_prepare()
  test-bdrv-drain: Fix incorrrect drain assumptions
  clang-tsa: Add macros for shared locks
  clang-tsa: Add TSA_ASSERT() macro
  Import clang-tsa.h
  async: Register/unregister aiocontext in graph lock list
  graph-lock: Implement guard macros
  graph-lock: Introduce a lock to protect block graph operations
  block: Factor out bdrv_drain_all_begin_nopoll()
  block/dirty-bitmap: convert coroutine-only functions to co_wrapper
  block: convert bdrv_create to co_wrapper
  block-coroutine-wrapper.py: support also basic return types
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 104 insertions, 283 deletions

diff --git a/tests/unit/test-bdrv-drain.c b/tests/unit/test-bdrv-drain.c
index 09dc4a4891..8cedea4959 100644
--- a/tests/unit/test-bdrv-drain.c
+++ b/tests/unit/test-bdrv-drain.c
@@ -38,16 +38,26 @@ typedef struct BDRVTestState {
     bool sleep_in_drain_begin;
 } BDRVTestState;
 
-static void coroutine_fn bdrv_test_co_drain_begin(BlockDriverState *bs)
+static void coroutine_fn sleep_in_drain_begin(void *opaque)
+{
+    BlockDriverState *bs = opaque;
+
+    qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, 100000);
+    bdrv_dec_in_flight(bs);
+}
+
+static void bdrv_test_drain_begin(BlockDriverState *bs)
 {
     BDRVTestState *s = bs->opaque;
     s->drain_count++;
     if (s->sleep_in_drain_begin) {
-        qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, 100000);
+        Coroutine *co = qemu_coroutine_create(sleep_in_drain_begin, bs);
+        bdrv_inc_in_flight(bs);
+        aio_co_enter(bdrv_get_aio_context(bs), co);
     }
 }
 
-static void coroutine_fn bdrv_test_co_drain_end(BlockDriverState *bs)
+static void bdrv_test_drain_end(BlockDriverState *bs)
 {
     BDRVTestState *s = bs->opaque;
     s->drain_count--;
@@ -101,8 +111,8 @@ static BlockDriver bdrv_test = {
     .bdrv_close             = bdrv_test_close,
     .bdrv_co_preadv         = bdrv_test_co_preadv,
 
-    .bdrv_co_drain_begin    = bdrv_test_co_drain_begin,
-    .bdrv_co_drain_end      = bdrv_test_co_drain_end,
+    .bdrv_drain_begin       = bdrv_test_drain_begin,
+    .bdrv_drain_end         = bdrv_test_drain_end,
 
     .bdrv_child_perm        = bdrv_default_perms,
 
@@ -146,7 +156,6 @@ static void call_in_coroutine(void (*entry)(void))
 enum drain_type {
     BDRV_DRAIN_ALL,
     BDRV_DRAIN,
-    BDRV_SUBTREE_DRAIN,
     DRAIN_TYPE_MAX,
 };
 
@@ -155,7 +164,6 @@ static void do_drain_begin(enum drain_type drain_type, BlockDriverState *bs)
     switch (drain_type) {
     case BDRV_DRAIN_ALL:        bdrv_drain_all_begin(); break;
     case BDRV_DRAIN:            bdrv_drained_begin(bs); break;
-    case BDRV_SUBTREE_DRAIN:    bdrv_subtree_drained_begin(bs); break;
     default:                    g_assert_not_reached();
     }
 }
@@ -165,7 +173,6 @@ static void do_drain_end(enum drain_type drain_type, BlockDriverState *bs)
     switch (drain_type) {
     case BDRV_DRAIN_ALL:        bdrv_drain_all_end(); break;
     case BDRV_DRAIN:            bdrv_drained_end(bs); break;
-    case BDRV_SUBTREE_DRAIN:    bdrv_subtree_drained_end(bs); break;
     default:                    g_assert_not_reached();
     }
 }
@@ -261,11 +268,6 @@ static void test_drv_cb_drain(void)
     test_drv_cb_common(BDRV_DRAIN, false);
 }
 
-static void test_drv_cb_drain_subtree(void)
-{
-    test_drv_cb_common(BDRV_SUBTREE_DRAIN, true);
-}
-
 static void test_drv_cb_co_drain_all(void)
 {
     call_in_coroutine(test_drv_cb_drain_all);
@@ -276,11 +278,6 @@ static void test_drv_cb_co_drain(void)
     call_in_coroutine(test_drv_cb_drain);
 }
 
-static void test_drv_cb_co_drain_subtree(void)
-{
-    call_in_coroutine(test_drv_cb_drain_subtree);
-}
-
 static void test_quiesce_common(enum drain_type drain_type, bool recursive)
 {
     BlockBackend *blk;
@@ -299,7 +296,11 @@ static void test_quiesce_common(enum drain_type drain_type, bool recursive)
 
     do_drain_begin(drain_type, bs);
 
-    g_assert_cmpint(bs->quiesce_counter, ==, 1);
+    if (drain_type == BDRV_DRAIN_ALL) {
+        g_assert_cmpint(bs->quiesce_counter, ==, 2);
+    } else {
+        g_assert_cmpint(bs->quiesce_counter, ==, 1);
+    }
     g_assert_cmpint(backing->quiesce_counter, ==, !!recursive);
 
     do_drain_end(drain_type, bs);
@@ -322,11 +323,6 @@ static void test_quiesce_drain(void)
     test_quiesce_common(BDRV_DRAIN, false);
 }
 
-static void test_quiesce_drain_subtree(void)
-{
-    test_quiesce_common(BDRV_SUBTREE_DRAIN, true);
-}
-
 static void test_quiesce_co_drain_all(void)
 {
     call_in_coroutine(test_quiesce_drain_all);
@@ -337,11 +333,6 @@ static void test_quiesce_co_drain(void)
     call_in_coroutine(test_quiesce_drain);
 }
 
-static void test_quiesce_co_drain_subtree(void)
-{
-    call_in_coroutine(test_quiesce_drain_subtree);
-}
-
 static void test_nested(void)
 {
     BlockBackend *blk;
@@ -361,8 +352,8 @@ static void test_nested(void)
 
     for (outer = 0; outer < DRAIN_TYPE_MAX; outer++) {
         for (inner = 0; inner < DRAIN_TYPE_MAX; inner++) {
-            int backing_quiesce = (outer != BDRV_DRAIN) +
-                                  (inner != BDRV_DRAIN);
+            int backing_quiesce = (outer == BDRV_DRAIN_ALL) +
+                                  (inner == BDRV_DRAIN_ALL);
 
             g_assert_cmpint(bs->quiesce_counter, ==, 0);
             g_assert_cmpint(backing->quiesce_counter, ==, 0);
@@ -372,10 +363,10 @@ static void test_nested(void)
             do_drain_begin(outer, bs);
             do_drain_begin(inner, bs);
 
-            g_assert_cmpint(bs->quiesce_counter, ==, 2);
+            g_assert_cmpint(bs->quiesce_counter, ==, 2 + !!backing_quiesce);
             g_assert_cmpint(backing->quiesce_counter, ==, backing_quiesce);
-            g_assert_cmpint(s->drain_count, ==, 2);
-            g_assert_cmpint(backing_s->drain_count, ==, backing_quiesce);
+            g_assert_cmpint(s->drain_count, ==, 1);
+            g_assert_cmpint(backing_s->drain_count, ==, !!backing_quiesce);
 
             do_drain_end(inner, bs);
             do_drain_end(outer, bs);
@@ -392,158 +383,6 @@ static void test_nested(void)
     blk_unref(blk);
 }
 
-static void test_multiparent(void)
-{
-    BlockBackend *blk_a, *blk_b;
-    BlockDriverState *bs_a, *bs_b, *backing;
-    BDRVTestState *a_s, *b_s, *backing_s;
-
-    blk_a = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
-    bs_a = bdrv_new_open_driver(&bdrv_test, "test-node-a", BDRV_O_RDWR,
-                                &error_abort);
-    a_s = bs_a->opaque;
-    blk_insert_bs(blk_a, bs_a, &error_abort);
-
-    blk_b = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
-    bs_b = bdrv_new_open_driver(&bdrv_test, "test-node-b", BDRV_O_RDWR,
-                                &error_abort);
-    b_s = bs_b->opaque;
-    blk_insert_bs(blk_b, bs_b, &error_abort);
-
-    backing = bdrv_new_open_driver(&bdrv_test, "backing", 0, &error_abort);
-    backing_s = backing->opaque;
-    bdrv_set_backing_hd(bs_a, backing, &error_abort);
-    bdrv_set_backing_hd(bs_b, backing, &error_abort);
-
-    g_assert_cmpint(bs_a->quiesce_counter, ==, 0);
-    g_assert_cmpint(bs_b->quiesce_counter, ==, 0);
-    g_assert_cmpint(backing->quiesce_counter, ==, 0);
-    g_assert_cmpint(a_s->drain_count, ==, 0);
-    g_assert_cmpint(b_s->drain_count, ==, 0);
-    g_assert_cmpint(backing_s->drain_count, ==, 0);
-
-    do_drain_begin(BDRV_SUBTREE_DRAIN, bs_a);
-
-    g_assert_cmpint(bs_a->quiesce_counter, ==, 1);
-    g_assert_cmpint(bs_b->quiesce_counter, ==, 1);
-    g_assert_cmpint(backing->quiesce_counter, ==, 1);
-    g_assert_cmpint(a_s->drain_count, ==, 1);
-    g_assert_cmpint(b_s->drain_count, ==, 1);
-    g_assert_cmpint(backing_s->drain_count, ==, 1);
-
-    do_drain_begin(BDRV_SUBTREE_DRAIN, bs_b);
-
-    g_assert_cmpint(bs_a->quiesce_counter, ==, 2);
-    g_assert_cmpint(bs_b->quiesce_counter, ==, 2);
-    g_assert_cmpint(backing->quiesce_counter, ==, 2);
-    g_assert_cmpint(a_s->drain_count, ==, 2);
-    g_assert_cmpint(b_s->drain_count, ==, 2);
-    g_assert_cmpint(backing_s->drain_count, ==, 2);
-
-    do_drain_end(BDRV_SUBTREE_DRAIN, bs_b);
-
-    g_assert_cmpint(bs_a->quiesce_counter, ==, 1);
-    g_assert_cmpint(bs_b->quiesce_counter, ==, 1);
-    g_assert_cmpint(backing->quiesce_counter, ==, 1);
-    g_assert_cmpint(a_s->drain_count, ==, 1);
-    g_assert_cmpint(b_s->drain_count, ==, 1);
-    g_assert_cmpint(backing_s->drain_count, ==, 1);
-
-    do_drain_end(BDRV_SUBTREE_DRAIN, bs_a);
-
-    g_assert_cmpint(bs_a->quiesce_counter, ==, 0);
-    g_assert_cmpint(bs_b->quiesce_counter, ==, 0);
-    g_assert_cmpint(backing->quiesce_counter, ==, 0);
-    g_assert_cmpint(a_s->drain_count, ==, 0);
-    g_assert_cmpint(b_s->drain_count, ==, 0);
-    g_assert_cmpint(backing_s->drain_count, ==, 0);
-
-    bdrv_unref(backing);
-    bdrv_unref(bs_a);
-    bdrv_unref(bs_b);
-    blk_unref(blk_a);
-    blk_unref(blk_b);
-}
-
-static void test_graph_change_drain_subtree(void)
-{
-    BlockBackend *blk_a, *blk_b;
-    BlockDriverState *bs_a, *bs_b, *backing;
-    BDRVTestState *a_s, *b_s, *backing_s;
-
-    blk_a = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
-    bs_a = bdrv_new_open_driver(&bdrv_test, "test-node-a", BDRV_O_RDWR,
-                                &error_abort);
-    a_s = bs_a->opaque;
-    blk_insert_bs(blk_a, bs_a, &error_abort);
-
-    blk_b = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
-    bs_b = bdrv_new_open_driver(&bdrv_test, "test-node-b", BDRV_O_RDWR,
-                                &error_abort);
-    b_s = bs_b->opaque;
-    blk_insert_bs(blk_b, bs_b, &error_abort);
-
-    backing = bdrv_new_open_driver(&bdrv_test, "backing", 0, &error_abort);
-    backing_s = backing->opaque;
-    bdrv_set_backing_hd(bs_a, backing, &error_abort);
-
-    g_assert_cmpint(bs_a->quiesce_counter, ==, 0);
-    g_assert_cmpint(bs_b->quiesce_counter, ==, 0);
-    g_assert_cmpint(backing->quiesce_counter, ==, 0);
-    g_assert_cmpint(a_s->drain_count, ==, 0);
-    g_assert_cmpint(b_s->drain_count, ==, 0);
-    g_assert_cmpint(backing_s->drain_count, ==, 0);
-
-    do_drain_begin(BDRV_SUBTREE_DRAIN, bs_a);
-    do_drain_begin(BDRV_SUBTREE_DRAIN, bs_a);
-    do_drain_begin(BDRV_SUBTREE_DRAIN, bs_a);
-    do_drain_begin(BDRV_SUBTREE_DRAIN, bs_b);
-    do_drain_begin(BDRV_SUBTREE_DRAIN, bs_b);
-
-    bdrv_set_backing_hd(bs_b, backing, &error_abort);
-    g_assert_cmpint(bs_a->quiesce_counter, ==, 5);
-    g_assert_cmpint(bs_b->quiesce_counter, ==, 5);
-    g_assert_cmpint(backing->quiesce_counter, ==, 5);
-    g_assert_cmpint(a_s->drain_count, ==, 5);
-    g_assert_cmpint(b_s->drain_count, ==, 5);
-    g_assert_cmpint(backing_s->drain_count, ==, 5);
-
-    bdrv_set_backing_hd(bs_b, NULL, &error_abort);
-    g_assert_cmpint(bs_a->quiesce_counter, ==, 3);
-    g_assert_cmpint(bs_b->quiesce_counter, ==, 2);
-    g_assert_cmpint(backing->quiesce_counter, ==, 3);
-    g_assert_cmpint(a_s->drain_count, ==, 3);
-    g_assert_cmpint(b_s->drain_count, ==, 2);
-    g_assert_cmpint(backing_s->drain_count, ==, 3);
-
-    bdrv_set_backing_hd(bs_b, backing, &error_abort);
-    g_assert_cmpint(bs_a->quiesce_counter, ==, 5);
-    g_assert_cmpint(bs_b->quiesce_counter, ==, 5);
-    g_assert_cmpint(backing->quiesce_counter, ==, 5);
-    g_assert_cmpint(a_s->drain_count, ==, 5);
-    g_assert_cmpint(b_s->drain_count, ==, 5);
-    g_assert_cmpint(backing_s->drain_count, ==, 5);
-
-    do_drain_end(BDRV_SUBTREE_DRAIN, bs_b);
-    do_drain_end(BDRV_SUBTREE_DRAIN, bs_b);
-    do_drain_end(BDRV_SUBTREE_DRAIN, bs_a);
-    do_drain_end(BDRV_SUBTREE_DRAIN, bs_a);
-    do_drain_end(BDRV_SUBTREE_DRAIN, bs_a);
-
-    g_assert_cmpint(bs_a->quiesce_counter, ==, 0);
-    g_assert_cmpint(bs_b->quiesce_counter, ==, 0);
-    g_assert_cmpint(backing->quiesce_counter, ==, 0);
-    g_assert_cmpint(a_s->drain_count, ==, 0);
-    g_assert_cmpint(b_s->drain_count, ==, 0);
-    g_assert_cmpint(backing_s->drain_count, ==, 0);
-
-    bdrv_unref(backing);
-    bdrv_unref(bs_a);
-    bdrv_unref(bs_b);
-    blk_unref(blk_a);
-    blk_unref(blk_b);
-}
-
 static void test_graph_change_drain_all(void)
 {
     BlockBackend *blk_a, *blk_b;
@@ -763,12 +602,6 @@ static void test_iothread_drain(void)
     test_iothread_common(BDRV_DRAIN, 1);
 }
 
-static void test_iothread_drain_subtree(void)
-{
-    test_iothread_common(BDRV_SUBTREE_DRAIN, 0);
-    test_iothread_common(BDRV_SUBTREE_DRAIN, 1);
-}
-
 
 typedef struct TestBlockJob {
     BlockJob common;
@@ -853,7 +686,6 @@ enum test_job_result {
 enum test_job_drain_node {
     TEST_JOB_DRAIN_SRC,
     TEST_JOB_DRAIN_SRC_CHILD,
-    TEST_JOB_DRAIN_SRC_PARENT,
 };
 
 static void test_blockjob_common_drain_node(enum drain_type drain_type,
@@ -891,9 +723,6 @@ static void test_blockjob_common_drain_node(enum drain_type drain_type,
     case TEST_JOB_DRAIN_SRC_CHILD:
         drain_bs = src_backing;
         break;
-    case TEST_JOB_DRAIN_SRC_PARENT:
-        drain_bs = src_overlay;
-        break;
     default:
         g_assert_not_reached();
     }
@@ -1045,10 +874,6 @@ static void test_blockjob_common(enum drain_type drain_type, bool use_iothread,
                                     TEST_JOB_DRAIN_SRC);
     test_blockjob_common_drain_node(drain_type, use_iothread, result,
                                     TEST_JOB_DRAIN_SRC_CHILD);
-    if (drain_type == BDRV_SUBTREE_DRAIN) {
-        test_blockjob_common_drain_node(drain_type, use_iothread, result,
-                                        TEST_JOB_DRAIN_SRC_PARENT);
-    }
 }
 
 static void test_blockjob_drain_all(void)
@@ -1061,11 +886,6 @@ static void test_blockjob_drain(void)
     test_blockjob_common(BDRV_DRAIN, false, TEST_JOB_SUCCESS);
 }
 
-static void test_blockjob_drain_subtree(void)
-{
-    test_blockjob_common(BDRV_SUBTREE_DRAIN, false, TEST_JOB_SUCCESS);
-}
-
 static void test_blockjob_error_drain_all(void)
 {
     test_blockjob_common(BDRV_DRAIN_ALL, false, TEST_JOB_FAIL_RUN);
@@ -1078,12 +898,6 @@ static void test_blockjob_error_drain(void)
     test_blockjob_common(BDRV_DRAIN, false, TEST_JOB_FAIL_PREPARE);
 }
 
-static void test_blockjob_error_drain_subtree(void)
-{
-    test_blockjob_common(BDRV_SUBTREE_DRAIN, false, TEST_JOB_FAIL_RUN);
-    test_blockjob_common(BDRV_SUBTREE_DRAIN, false, TEST_JOB_FAIL_PREPARE);
-}
-
 static void test_blockjob_iothread_drain_all(void)
 {
     test_blockjob_common(BDRV_DRAIN_ALL, true, TEST_JOB_SUCCESS);
@@ -1094,11 +908,6 @@ static void test_blockjob_iothread_drain(void)
     test_blockjob_common(BDRV_DRAIN, true, TEST_JOB_SUCCESS);
 }
 
-static void test_blockjob_iothread_drain_subtree(void)
-{
-    test_blockjob_common(BDRV_SUBTREE_DRAIN, true, TEST_JOB_SUCCESS);
-}
-
 static void test_blockjob_iothread_error_drain_all(void)
 {
     test_blockjob_common(BDRV_DRAIN_ALL, true, TEST_JOB_FAIL_RUN);
@@ -1111,12 +920,6 @@ static void test_blockjob_iothread_error_drain(void)
     test_blockjob_common(BDRV_DRAIN, true, TEST_JOB_FAIL_PREPARE);
 }
 
-static void test_blockjob_iothread_error_drain_subtree(void)
-{
-    test_blockjob_common(BDRV_SUBTREE_DRAIN, true, TEST_JOB_FAIL_RUN);
-    test_blockjob_common(BDRV_SUBTREE_DRAIN, true, TEST_JOB_FAIL_PREPARE);
-}
-
 
 typedef struct BDRVTestTopState {
     BdrvChild *wait_child;
@@ -1263,14 +1066,6 @@ static void do_test_delete_by_drain(bool detach_instead_of_delete,
         bdrv_drain(child_bs);
         bdrv_unref(child_bs);
         break;
-    case BDRV_SUBTREE_DRAIN:
-        /* Would have to ref/unref bs here for !detach_instead_of_delete, but
-         * then the whole test becomes pointless because the graph changes
-         * don't occur during the drain any more. */
-        assert(detach_instead_of_delete);
-        bdrv_subtree_drained_begin(bs);
-        bdrv_subtree_drained_end(bs);
-        break;
     case BDRV_DRAIN_ALL:
         bdrv_drain_all_begin();
         bdrv_drain_all_end();
@@ -1305,11 +1100,6 @@ static void test_detach_by_drain(void)
     do_test_delete_by_drain(true, BDRV_DRAIN);
 }
 
-static void test_detach_by_drain_subtree(void)
-{
-    do_test_delete_by_drain(true, BDRV_SUBTREE_DRAIN);
-}
-
 
 struct detach_by_parent_data {
     BlockDriverState *parent_b;
@@ -1317,6 +1107,7 @@ struct detach_by_parent_data {
     BlockDriverState *c;
     BdrvChild *child_c;
     bool by_parent_cb;
+    bool detach_on_drain;
 };
 static struct detach_by_parent_data detach_by_parent_data;
 
@@ -1324,6 +1115,7 @@ static void detach_indirect_bh(void *opaque)
 {
     struct detach_by_parent_data *data = opaque;
 
+    bdrv_dec_in_flight(data->child_b->bs);
     bdrv_unref_child(data->parent_b, data->child_b);
 
     bdrv_ref(data->c);
@@ -1338,12 +1130,21 @@ static void detach_by_parent_aio_cb(void *opaque, int ret)
 
     g_assert_cmpint(ret, ==, 0);
     if (data->by_parent_cb) {
+        bdrv_inc_in_flight(data->child_b->bs);
         detach_indirect_bh(data);
     }
 }
 
 static void detach_by_driver_cb_drained_begin(BdrvChild *child)
 {
+    struct detach_by_parent_data *data = &detach_by_parent_data;
+
+    if (!data->detach_on_drain) {
+        return;
+    }
+    data->detach_on_drain = false;
+
+    bdrv_inc_in_flight(data->child_b->bs);
     aio_bh_schedule_oneshot(qemu_get_current_aio_context(),
                             detach_indirect_bh, &detach_by_parent_data);
     child_of_bds.drained_begin(child);
@@ -1384,8 +1185,14 @@ static void test_detach_indirect(bool by_parent_cb)
         detach_by_driver_cb_class = child_of_bds;
         detach_by_driver_cb_class.drained_begin =
             detach_by_driver_cb_drained_begin;
+        detach_by_driver_cb_class.drained_end = NULL;
+        detach_by_driver_cb_class.drained_poll = NULL;
     }
 
+    detach_by_parent_data = (struct detach_by_parent_data) {
+        .detach_on_drain = false,
+    };
+
     /* Create all involved nodes */
     parent_a = bdrv_new_open_driver(&bdrv_test, "parent-a", BDRV_O_RDWR,
                                     &error_abort);
@@ -1437,12 +1244,16 @@ static void test_detach_indirect(bool by_parent_cb)
         .child_b = child_b,
         .c = c,
         .by_parent_cb = by_parent_cb,
+        .detach_on_drain = true,
     };
     acb = blk_aio_preadv(blk, 0, &qiov, 0, detach_by_parent_aio_cb, NULL);
     g_assert(acb != NULL);
 
     /* Drain and check the expected result */
-    bdrv_subtree_drained_begin(parent_b);
+    bdrv_drained_begin(parent_b);
+    bdrv_drained_begin(a);
+    bdrv_drained_begin(b);
+    bdrv_drained_begin(c);
 
     g_assert(detach_by_parent_data.child_c != NULL);
 
@@ -1457,12 +1268,15 @@ static void test_detach_indirect(bool by_parent_cb)
     g_assert(QLIST_NEXT(child_a, next) == NULL);
 
     g_assert_cmpint(parent_a->quiesce_counter, ==, 1);
-    g_assert_cmpint(parent_b->quiesce_counter, ==, 1);
+    g_assert_cmpint(parent_b->quiesce_counter, ==, 3);
     g_assert_cmpint(a->quiesce_counter, ==, 1);
-    g_assert_cmpint(b->quiesce_counter, ==, 0);
+    g_assert_cmpint(b->quiesce_counter, ==, 1);
     g_assert_cmpint(c->quiesce_counter, ==, 1);
 
-    bdrv_subtree_drained_end(parent_b);
+    bdrv_drained_end(parent_b);
+    bdrv_drained_end(a);
+    bdrv_drained_end(b);
+    bdrv_drained_end(c);
 
     bdrv_unref(parent_b);
     blk_unref(blk);
@@ -1693,6 +1507,7 @@ static void test_blockjob_commit_by_drained_end(void)
     bdrv_drained_begin(bs_child);
     g_assert(!job_has_completed);
     bdrv_drained_end(bs_child);
+    aio_poll(qemu_get_aio_context(), false);
     g_assert(job_has_completed);
 
     bdrv_unref(bs_parents[0]);
@@ -1848,6 +1663,7 @@ static void test_drop_intermediate_poll(void)
 
     g_assert(!job_has_completed);
     ret = bdrv_drop_intermediate(chain[1], chain[0], NULL);
+    aio_poll(qemu_get_aio_context(), false);
     g_assert(ret == 0);
     g_assert(job_has_completed);
 
@@ -1856,6 +1672,7 @@ static void test_drop_intermediate_poll(void)
 
 
 typedef struct BDRVReplaceTestState {
+    bool setup_completed;
     bool was_drained;
     bool was_undrained;
     bool has_read;
@@ -1916,52 +1733,78 @@ static int coroutine_fn bdrv_replace_test_co_preadv(BlockDriverState *bs,
     return 0;
 }
 
+static void coroutine_fn bdrv_replace_test_drain_co(void *opaque)
+{
+    BlockDriverState *bs = opaque;
+    BDRVReplaceTestState *s = bs->opaque;
+
+    /* Keep waking io_co up until it is done */
+    while (s->io_co) {
+        aio_co_wake(s->io_co);
+        s->io_co = NULL;
+        qemu_coroutine_yield();
+    }
+    s->drain_co = NULL;
+    bdrv_dec_in_flight(bs);
+}
+
 /**
  * If .drain_count is 0, wake up .io_co if there is one; and set
  * .was_drained.
  * Increment .drain_count.
  */
-static void coroutine_fn bdrv_replace_test_co_drain_begin(BlockDriverState *bs)
+static void bdrv_replace_test_drain_begin(BlockDriverState *bs)
 {
     BDRVReplaceTestState *s = bs->opaque;
 
-    if (!s->drain_count) {
-        /* Keep waking io_co up until it is done */
-        s->drain_co = qemu_coroutine_self();
-        while (s->io_co) {
-            aio_co_wake(s->io_co);
-            s->io_co = NULL;
-            qemu_coroutine_yield();
-        }
-        s->drain_co = NULL;
+    if (!s->setup_completed) {
+        return;
+    }
 
+    if (!s->drain_count) {
+        s->drain_co = qemu_coroutine_create(bdrv_replace_test_drain_co, bs);
+        bdrv_inc_in_flight(bs);
+        aio_co_enter(bdrv_get_aio_context(bs), s->drain_co);
         s->was_drained = true;
     }
     s->drain_count++;
 }
 
+static void coroutine_fn bdrv_replace_test_read_entry(void *opaque)
+{
+    BlockDriverState *bs = opaque;
+    char data;
+    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, &data, 1);
+    int ret;
+
+    /* Queue a read request post-drain */
+    ret = bdrv_replace_test_co_preadv(bs, 0, 1, &qiov, 0);
+    g_assert(ret >= 0);
+    bdrv_dec_in_flight(bs);
+}
+
 /**
  * Reduce .drain_count, set .was_undrained once it reaches 0.
  * If .drain_count reaches 0 and the node has a backing file, issue a
  * read request.
  */
-static void coroutine_fn bdrv_replace_test_co_drain_end(BlockDriverState *bs)
+static void bdrv_replace_test_drain_end(BlockDriverState *bs)
 {
     BDRVReplaceTestState *s = bs->opaque;
 
+    if (!s->setup_completed) {
+        return;
+    }
+
     g_assert(s->drain_count > 0);
     if (!--s->drain_count) {
-        int ret;
-
         s->was_undrained = true;
 
         if (bs->backing) {
-            char data;
-            QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, &data, 1);
-
-            /* Queue a read request post-drain */
-            ret = bdrv_replace_test_co_preadv(bs, 0, 1, &qiov, 0);
-            g_assert(ret >= 0);
+            Coroutine *co = qemu_coroutine_create(bdrv_replace_test_read_entry,
+                                                  bs);
+            bdrv_inc_in_flight(bs);
+            aio_co_enter(bdrv_get_aio_context(bs), co);
         }
     }
 }
@@ -1974,8 +1817,8 @@ static BlockDriver bdrv_replace_test = {
     .bdrv_close             = bdrv_replace_test_close,
     .bdrv_co_preadv         = bdrv_replace_test_co_preadv,
 
-    .bdrv_co_drain_begin    = bdrv_replace_test_co_drain_begin,
-    .bdrv_co_drain_end      = bdrv_replace_test_co_drain_end,
+    .bdrv_drain_begin       = bdrv_replace_test_drain_begin,
+    .bdrv_drain_end         = bdrv_replace_test_drain_end,
 
     .bdrv_child_perm        = bdrv_default_perms,
 };
@@ -2051,6 +1894,7 @@ static void do_test_replace_child_mid_drain(int old_drain_count,
     bdrv_ref(old_child_bs);
     bdrv_attach_child(parent_bs, old_child_bs, "child", &child_of_bds,
                       BDRV_CHILD_COW, &error_abort);
+    parent_s->setup_completed = true;
 
     for (i = 0; i < old_drain_count; i++) {
         bdrv_drained_begin(old_child_bs);
@@ -2172,70 +2016,47 @@ int main(int argc, char **argv)
 
     g_test_add_func("/bdrv-drain/driver-cb/drain_all", test_drv_cb_drain_all);
     g_test_add_func("/bdrv-drain/driver-cb/drain", test_drv_cb_drain);
-    g_test_add_func("/bdrv-drain/driver-cb/drain_subtree",
-                    test_drv_cb_drain_subtree);
 
     g_test_add_func("/bdrv-drain/driver-cb/co/drain_all",
                     test_drv_cb_co_drain_all);
     g_test_add_func("/bdrv-drain/driver-cb/co/drain", test_drv_cb_co_drain);
-    g_test_add_func("/bdrv-drain/driver-cb/co/drain_subtree",
-                    test_drv_cb_co_drain_subtree);
-
 
     g_test_add_func("/bdrv-drain/quiesce/drain_all", test_quiesce_drain_all);
     g_test_add_func("/bdrv-drain/quiesce/drain", test_quiesce_drain);
-    g_test_add_func("/bdrv-drain/quiesce/drain_subtree",
-                    test_quiesce_drain_subtree);
 
     g_test_add_func("/bdrv-drain/quiesce/co/drain_all",
                     test_quiesce_co_drain_all);
     g_test_add_func("/bdrv-drain/quiesce/co/drain", test_quiesce_co_drain);
-    g_test_add_func("/bdrv-drain/quiesce/co/drain_subtree",
-                    test_quiesce_co_drain_subtree);
 
     g_test_add_func("/bdrv-drain/nested", test_nested);
-    g_test_add_func("/bdrv-drain/multiparent", test_multiparent);
 
-    g_test_add_func("/bdrv-drain/graph-change/drain_subtree",
-                    test_graph_change_drain_subtree);
     g_test_add_func("/bdrv-drain/graph-change/drain_all",
                     test_graph_change_drain_all);
 
     g_test_add_func("/bdrv-drain/iothread/drain_all", test_iothread_drain_all);
     g_test_add_func("/bdrv-drain/iothread/drain", test_iothread_drain);
-    g_test_add_func("/bdrv-drain/iothread/drain_subtree",
-                    test_iothread_drain_subtree);
 
     g_test_add_func("/bdrv-drain/blockjob/drain_all", test_blockjob_drain_all);
     g_test_add_func("/bdrv-drain/blockjob/drain", test_blockjob_drain);
-    g_test_add_func("/bdrv-drain/blockjob/drain_subtree",
-                    test_blockjob_drain_subtree);
 
     g_test_add_func("/bdrv-drain/blockjob/error/drain_all",
                     test_blockjob_error_drain_all);
     g_test_add_func("/bdrv-drain/blockjob/error/drain",
                     test_blockjob_error_drain);
-    g_test_add_func("/bdrv-drain/blockjob/error/drain_subtree",
-                    test_blockjob_error_drain_subtree);
 
     g_test_add_func("/bdrv-drain/blockjob/iothread/drain_all",
                     test_blockjob_iothread_drain_all);
     g_test_add_func("/bdrv-drain/blockjob/iothread/drain",
                     test_blockjob_iothread_drain);
-    g_test_add_func("/bdrv-drain/blockjob/iothread/drain_subtree",
-                    test_blockjob_iothread_drain_subtree);
 
     g_test_add_func("/bdrv-drain/blockjob/iothread/error/drain_all",
                     test_blockjob_iothread_error_drain_all);
     g_test_add_func("/bdrv-drain/blockjob/iothread/error/drain",
                     test_blockjob_iothread_error_drain);
-    g_test_add_func("/bdrv-drain/blockjob/iothread/error/drain_subtree",
-                    test_blockjob_iothread_error_drain_subtree);
 
     g_test_add_func("/bdrv-drain/deletion/drain", test_delete_by_drain);
     g_test_add_func("/bdrv-drain/detach/drain_all", test_detach_by_drain_all);
     g_test_add_func("/bdrv-drain/detach/drain", test_detach_by_drain);
-    g_test_add_func("/bdrv-drain/detach/drain_subtree", test_detach_by_drain_subtree);
     g_test_add_func("/bdrv-drain/detach/parent_cb", test_detach_by_parent_cb);
     g_test_add_func("/bdrv-drain/detach/driver_cb", test_detach_by_driver_cb);