]> git.proxmox.com Git - mirror_qemu.git/blobdiff - tests/test-bdrv-drain.c
Merge tag 'pull-maintainer-may24-160524-2' of https://gitlab.com/stsquad/qemu into...
[mirror_qemu.git] / tests / test-bdrv-drain.c
diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
deleted file mode 100644 (file)
index 44e658b..0000000
+++ /dev/null
@@ -1,1616 +0,0 @@
-/*
- * Block node draining tests
- *
- * Copyright (c) 2017 Kevin Wolf <kwolf@redhat.com>
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
- * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
-#include "qemu/osdep.h"
-#include "block/block.h"
-#include "block/blockjob_int.h"
-#include "sysemu/block-backend.h"
-#include "qapi/error.h"
-#include "iothread.h"
-
-static QemuEvent done_event;
-
-typedef struct BDRVTestState {
-    int drain_count;
-    AioContext *bh_indirection_ctx;
-    bool sleep_in_drain_begin;
-} BDRVTestState;
-
-static void coroutine_fn bdrv_test_co_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);
-    }
-}
-
-static void coroutine_fn bdrv_test_co_drain_end(BlockDriverState *bs)
-{
-    BDRVTestState *s = bs->opaque;
-    s->drain_count--;
-}
-
-static void bdrv_test_close(BlockDriverState *bs)
-{
-    BDRVTestState *s = bs->opaque;
-    g_assert_cmpint(s->drain_count, >, 0);
-}
-
-static void co_reenter_bh(void *opaque)
-{
-    aio_co_wake(opaque);
-}
-
-static int coroutine_fn bdrv_test_co_preadv(BlockDriverState *bs,
-                                            uint64_t offset, uint64_t bytes,
-                                            QEMUIOVector *qiov, int flags)
-{
-    BDRVTestState *s = bs->opaque;
-
-    /* We want this request to stay until the polling loop in drain waits for
-     * it to complete. We need to sleep a while as bdrv_drain_invoke() comes
-     * first and polls its result, too, but it shouldn't accidentally complete
-     * this request yet. */
-    qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, 100000);
-
-    if (s->bh_indirection_ctx) {
-        aio_bh_schedule_oneshot(s->bh_indirection_ctx, co_reenter_bh,
-                                qemu_coroutine_self());
-        qemu_coroutine_yield();
-    }
-
-    return 0;
-}
-
-static void bdrv_test_child_perm(BlockDriverState *bs, BdrvChild *c,
-                                 const BdrvChildRole *role,
-                                 BlockReopenQueue *reopen_queue,
-                                 uint64_t perm, uint64_t shared,
-                                 uint64_t *nperm, uint64_t *nshared)
-{
-    /* bdrv_format_default_perms() accepts only these two, so disguise
-     * detach_by_driver_cb_role as one of them. */
-    if (role != &child_file && role != &child_backing) {
-        role = &child_file;
-    }
-
-    bdrv_format_default_perms(bs, c, role, reopen_queue, perm, shared,
-                              nperm, nshared);
-}
-
-static BlockDriver bdrv_test = {
-    .format_name            = "test",
-    .instance_size          = sizeof(BDRVTestState),
-
-    .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_child_perm        = bdrv_test_child_perm,
-};
-
-static void aio_ret_cb(void *opaque, int ret)
-{
-    int *aio_ret = opaque;
-    *aio_ret = ret;
-}
-
-typedef struct CallInCoroutineData {
-    void (*entry)(void);
-    bool done;
-} CallInCoroutineData;
-
-static coroutine_fn void call_in_coroutine_entry(void *opaque)
-{
-    CallInCoroutineData *data = opaque;
-
-    data->entry();
-    data->done = true;
-}
-
-static void call_in_coroutine(void (*entry)(void))
-{
-    Coroutine *co;
-    CallInCoroutineData data = {
-        .entry  = entry,
-        .done   = false,
-    };
-
-    co = qemu_coroutine_create(call_in_coroutine_entry, &data);
-    qemu_coroutine_enter(co);
-    while (!data.done) {
-        aio_poll(qemu_get_aio_context(), true);
-    }
-}
-
-enum drain_type {
-    BDRV_DRAIN_ALL,
-    BDRV_DRAIN,
-    BDRV_SUBTREE_DRAIN,
-    DRAIN_TYPE_MAX,
-};
-
-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();
-    }
-}
-
-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();
-    }
-}
-
-static void do_drain_begin_unlocked(enum drain_type drain_type, BlockDriverState *bs)
-{
-    if (drain_type != BDRV_DRAIN_ALL) {
-        aio_context_acquire(bdrv_get_aio_context(bs));
-    }
-    do_drain_begin(drain_type, bs);
-    if (drain_type != BDRV_DRAIN_ALL) {
-        aio_context_release(bdrv_get_aio_context(bs));
-    }
-}
-
-static void do_drain_end_unlocked(enum drain_type drain_type, BlockDriverState *bs)
-{
-    if (drain_type != BDRV_DRAIN_ALL) {
-        aio_context_acquire(bdrv_get_aio_context(bs));
-    }
-    do_drain_end(drain_type, bs);
-    if (drain_type != BDRV_DRAIN_ALL) {
-        aio_context_release(bdrv_get_aio_context(bs));
-    }
-}
-
-static void test_drv_cb_common(enum drain_type drain_type, bool recursive)
-{
-    BlockBackend *blk;
-    BlockDriverState *bs, *backing;
-    BDRVTestState *s, *backing_s;
-    BlockAIOCB *acb;
-    int aio_ret;
-
-    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, NULL, 0);
-
-    blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
-    bs = bdrv_new_open_driver(&bdrv_test, "test-node", BDRV_O_RDWR,
-                              &error_abort);
-    s = bs->opaque;
-    blk_insert_bs(blk, bs, &error_abort);
-
-    backing = bdrv_new_open_driver(&bdrv_test, "backing", 0, &error_abort);
-    backing_s = backing->opaque;
-    bdrv_set_backing_hd(bs, backing, &error_abort);
-
-    /* Simple bdrv_drain_all_begin/end pair, check that CBs are called */
-    g_assert_cmpint(s->drain_count, ==, 0);
-    g_assert_cmpint(backing_s->drain_count, ==, 0);
-
-    do_drain_begin(drain_type, bs);
-
-    g_assert_cmpint(s->drain_count, ==, 1);
-    g_assert_cmpint(backing_s->drain_count, ==, !!recursive);
-
-    do_drain_end(drain_type, bs);
-
-    g_assert_cmpint(s->drain_count, ==, 0);
-    g_assert_cmpint(backing_s->drain_count, ==, 0);
-
-    /* Now do the same while a request is pending */
-    aio_ret = -EINPROGRESS;
-    acb = blk_aio_preadv(blk, 0, &qiov, 0, aio_ret_cb, &aio_ret);
-    g_assert(acb != NULL);
-    g_assert_cmpint(aio_ret, ==, -EINPROGRESS);
-
-    g_assert_cmpint(s->drain_count, ==, 0);
-    g_assert_cmpint(backing_s->drain_count, ==, 0);
-
-    do_drain_begin(drain_type, bs);
-
-    g_assert_cmpint(aio_ret, ==, 0);
-    g_assert_cmpint(s->drain_count, ==, 1);
-    g_assert_cmpint(backing_s->drain_count, ==, !!recursive);
-
-    do_drain_end(drain_type, bs);
-
-    g_assert_cmpint(s->drain_count, ==, 0);
-    g_assert_cmpint(backing_s->drain_count, ==, 0);
-
-    bdrv_unref(backing);
-    bdrv_unref(bs);
-    blk_unref(blk);
-}
-
-static void test_drv_cb_drain_all(void)
-{
-    test_drv_cb_common(BDRV_DRAIN_ALL, true);
-}
-
-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);
-}
-
-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;
-    BlockDriverState *bs, *backing;
-
-    blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
-    bs = bdrv_new_open_driver(&bdrv_test, "test-node", BDRV_O_RDWR,
-                              &error_abort);
-    blk_insert_bs(blk, bs, &error_abort);
-
-    backing = bdrv_new_open_driver(&bdrv_test, "backing", 0, &error_abort);
-    bdrv_set_backing_hd(bs, backing, &error_abort);
-
-    g_assert_cmpint(bs->quiesce_counter, ==, 0);
-    g_assert_cmpint(backing->quiesce_counter, ==, 0);
-
-    do_drain_begin(drain_type, bs);
-
-    g_assert_cmpint(bs->quiesce_counter, ==, 1);
-    g_assert_cmpint(backing->quiesce_counter, ==, !!recursive);
-
-    do_drain_end(drain_type, bs);
-
-    g_assert_cmpint(bs->quiesce_counter, ==, 0);
-    g_assert_cmpint(backing->quiesce_counter, ==, 0);
-
-    bdrv_unref(backing);
-    bdrv_unref(bs);
-    blk_unref(blk);
-}
-
-static void test_quiesce_drain_all(void)
-{
-    test_quiesce_common(BDRV_DRAIN_ALL, true);
-}
-
-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);
-}
-
-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;
-    BlockDriverState *bs, *backing;
-    BDRVTestState *s, *backing_s;
-    enum drain_type outer, inner;
-
-    blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
-    bs = bdrv_new_open_driver(&bdrv_test, "test-node", BDRV_O_RDWR,
-                              &error_abort);
-    s = bs->opaque;
-    blk_insert_bs(blk, bs, &error_abort);
-
-    backing = bdrv_new_open_driver(&bdrv_test, "backing", 0, &error_abort);
-    backing_s = backing->opaque;
-    bdrv_set_backing_hd(bs, backing, &error_abort);
-
-    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);
-
-            g_assert_cmpint(bs->quiesce_counter, ==, 0);
-            g_assert_cmpint(backing->quiesce_counter, ==, 0);
-            g_assert_cmpint(s->drain_count, ==, 0);
-            g_assert_cmpint(backing_s->drain_count, ==, 0);
-
-            do_drain_begin(outer, bs);
-            do_drain_begin(inner, bs);
-
-            g_assert_cmpint(bs->quiesce_counter, ==, 2);
-            g_assert_cmpint(backing->quiesce_counter, ==, backing_quiesce);
-            g_assert_cmpint(s->drain_count, ==, 2);
-            g_assert_cmpint(backing_s->drain_count, ==, backing_quiesce);
-
-            do_drain_end(inner, bs);
-            do_drain_end(outer, bs);
-
-            g_assert_cmpint(bs->quiesce_counter, ==, 0);
-            g_assert_cmpint(backing->quiesce_counter, ==, 0);
-            g_assert_cmpint(s->drain_count, ==, 0);
-            g_assert_cmpint(backing_s->drain_count, ==, 0);
-        }
-    }
-
-    bdrv_unref(backing);
-    bdrv_unref(bs);
-    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;
-    BlockDriverState *bs_a, *bs_b;
-    BDRVTestState *a_s, *b_s;
-
-    /* Create node A with a BlockBackend */
-    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);
-
-    g_assert_cmpint(bs_a->quiesce_counter, ==, 0);
-    g_assert_cmpint(a_s->drain_count, ==, 0);
-
-    /* Call bdrv_drain_all_begin() */
-    bdrv_drain_all_begin();
-
-    g_assert_cmpint(bs_a->quiesce_counter, ==, 1);
-    g_assert_cmpint(a_s->drain_count, ==, 1);
-
-    /* Create node B with a BlockBackend */
-    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);
-
-    g_assert_cmpint(bs_a->quiesce_counter, ==, 1);
-    g_assert_cmpint(bs_b->quiesce_counter, ==, 1);
-    g_assert_cmpint(a_s->drain_count, ==, 1);
-    g_assert_cmpint(b_s->drain_count, ==, 1);
-
-    /* Unref and finally delete node A */
-    blk_unref(blk_a);
-
-    g_assert_cmpint(bs_a->quiesce_counter, ==, 1);
-    g_assert_cmpint(bs_b->quiesce_counter, ==, 1);
-    g_assert_cmpint(a_s->drain_count, ==, 1);
-    g_assert_cmpint(b_s->drain_count, ==, 1);
-
-    bdrv_unref(bs_a);
-
-    g_assert_cmpint(bs_b->quiesce_counter, ==, 1);
-    g_assert_cmpint(b_s->drain_count, ==, 1);
-
-    /* End the drained section */
-    bdrv_drain_all_end();
-
-    g_assert_cmpint(bs_b->quiesce_counter, ==, 0);
-    g_assert_cmpint(b_s->drain_count, ==, 0);
-
-    bdrv_unref(bs_b);
-    blk_unref(blk_b);
-}
-
-struct test_iothread_data {
-    BlockDriverState *bs;
-    enum drain_type drain_type;
-    int *aio_ret;
-};
-
-static void test_iothread_drain_entry(void *opaque)
-{
-    struct test_iothread_data *data = opaque;
-
-    aio_context_acquire(bdrv_get_aio_context(data->bs));
-    do_drain_begin(data->drain_type, data->bs);
-    g_assert_cmpint(*data->aio_ret, ==, 0);
-    do_drain_end(data->drain_type, data->bs);
-    aio_context_release(bdrv_get_aio_context(data->bs));
-
-    qemu_event_set(&done_event);
-}
-
-static void test_iothread_aio_cb(void *opaque, int ret)
-{
-    int *aio_ret = opaque;
-    *aio_ret = ret;
-    qemu_event_set(&done_event);
-}
-
-static void test_iothread_main_thread_bh(void *opaque)
-{
-    struct test_iothread_data *data = opaque;
-
-    /* Test that the AioContext is not yet locked in a random BH that is
-     * executed during drain, otherwise this would deadlock. */
-    aio_context_acquire(bdrv_get_aio_context(data->bs));
-    bdrv_flush(data->bs);
-    aio_context_release(bdrv_get_aio_context(data->bs));
-}
-
-/*
- * Starts an AIO request on a BDS that runs in the AioContext of iothread 1.
- * The request involves a BH on iothread 2 before it can complete.
- *
- * @drain_thread = 0 means that do_drain_begin/end are called from the main
- * thread, @drain_thread = 1 means that they are called from iothread 1. Drain
- * for this BDS cannot be called from iothread 2 because only the main thread
- * may do cross-AioContext polling.
- */
-static void test_iothread_common(enum drain_type drain_type, int drain_thread)
-{
-    BlockBackend *blk;
-    BlockDriverState *bs;
-    BDRVTestState *s;
-    BlockAIOCB *acb;
-    int aio_ret;
-    struct test_iothread_data data;
-
-    IOThread *a = iothread_new();
-    IOThread *b = iothread_new();
-    AioContext *ctx_a = iothread_get_aio_context(a);
-    AioContext *ctx_b = iothread_get_aio_context(b);
-
-    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, NULL, 0);
-
-    /* bdrv_drain_all() may only be called from the main loop thread */
-    if (drain_type == BDRV_DRAIN_ALL && drain_thread != 0) {
-        goto out;
-    }
-
-    blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
-    bs = bdrv_new_open_driver(&bdrv_test, "test-node", BDRV_O_RDWR,
-                              &error_abort);
-    s = bs->opaque;
-    blk_insert_bs(blk, bs, &error_abort);
-
-    blk_set_aio_context(blk, ctx_a, &error_abort);
-    aio_context_acquire(ctx_a);
-
-    s->bh_indirection_ctx = ctx_b;
-
-    aio_ret = -EINPROGRESS;
-    qemu_event_reset(&done_event);
-
-    if (drain_thread == 0) {
-        acb = blk_aio_preadv(blk, 0, &qiov, 0, test_iothread_aio_cb, &aio_ret);
-    } else {
-        acb = blk_aio_preadv(blk, 0, &qiov, 0, aio_ret_cb, &aio_ret);
-    }
-    g_assert(acb != NULL);
-    g_assert_cmpint(aio_ret, ==, -EINPROGRESS);
-
-    aio_context_release(ctx_a);
-
-    data = (struct test_iothread_data) {
-        .bs         = bs,
-        .drain_type = drain_type,
-        .aio_ret    = &aio_ret,
-    };
-
-    switch (drain_thread) {
-    case 0:
-        if (drain_type != BDRV_DRAIN_ALL) {
-            aio_context_acquire(ctx_a);
-        }
-
-        aio_bh_schedule_oneshot(ctx_a, test_iothread_main_thread_bh, &data);
-
-        /* The request is running on the IOThread a. Draining its block device
-         * will make sure that it has completed as far as the BDS is concerned,
-         * but the drain in this thread can continue immediately after
-         * bdrv_dec_in_flight() and aio_ret might be assigned only slightly
-         * later. */
-        do_drain_begin(drain_type, bs);
-        g_assert_cmpint(bs->in_flight, ==, 0);
-
-        if (drain_type != BDRV_DRAIN_ALL) {
-            aio_context_release(ctx_a);
-        }
-        qemu_event_wait(&done_event);
-        if (drain_type != BDRV_DRAIN_ALL) {
-            aio_context_acquire(ctx_a);
-        }
-
-        g_assert_cmpint(aio_ret, ==, 0);
-        do_drain_end(drain_type, bs);
-
-        if (drain_type != BDRV_DRAIN_ALL) {
-            aio_context_release(ctx_a);
-        }
-        break;
-    case 1:
-        aio_bh_schedule_oneshot(ctx_a, test_iothread_drain_entry, &data);
-        qemu_event_wait(&done_event);
-        break;
-    default:
-        g_assert_not_reached();
-    }
-
-    aio_context_acquire(ctx_a);
-    blk_set_aio_context(blk, qemu_get_aio_context(), &error_abort);
-    aio_context_release(ctx_a);
-
-    bdrv_unref(bs);
-    blk_unref(blk);
-
-out:
-    iothread_join(a);
-    iothread_join(b);
-}
-
-static void test_iothread_drain_all(void)
-{
-    test_iothread_common(BDRV_DRAIN_ALL, 0);
-    test_iothread_common(BDRV_DRAIN_ALL, 1);
-}
-
-static void test_iothread_drain(void)
-{
-    test_iothread_common(BDRV_DRAIN, 0);
-    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;
-    int run_ret;
-    int prepare_ret;
-    bool running;
-    bool should_complete;
-} TestBlockJob;
-
-static int test_job_prepare(Job *job)
-{
-    TestBlockJob *s = container_of(job, TestBlockJob, common.job);
-
-    /* Provoke an AIO_WAIT_WHILE() call to verify there is no deadlock */
-    blk_flush(s->common.blk);
-    return s->prepare_ret;
-}
-
-static void test_job_commit(Job *job)
-{
-    TestBlockJob *s = container_of(job, TestBlockJob, common.job);
-
-    /* Provoke an AIO_WAIT_WHILE() call to verify there is no deadlock */
-    blk_flush(s->common.blk);
-}
-
-static void test_job_abort(Job *job)
-{
-    TestBlockJob *s = container_of(job, TestBlockJob, common.job);
-
-    /* Provoke an AIO_WAIT_WHILE() call to verify there is no deadlock */
-    blk_flush(s->common.blk);
-}
-
-static int coroutine_fn test_job_run(Job *job, Error **errp)
-{
-    TestBlockJob *s = container_of(job, TestBlockJob, common.job);
-
-    /* We are running the actual job code past the pause point in
-     * job_co_entry(). */
-    s->running = true;
-
-    job_transition_to_ready(&s->common.job);
-    while (!s->should_complete) {
-        /* Avoid job_sleep_ns() because it marks the job as !busy. We want to
-         * emulate some actual activity (probably some I/O) here so that drain
-         * has to wait for this activity to stop. */
-        qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, 1000000);
-
-        job_pause_point(&s->common.job);
-    }
-
-    return s->run_ret;
-}
-
-static void test_job_complete(Job *job, Error **errp)
-{
-    TestBlockJob *s = container_of(job, TestBlockJob, common.job);
-    s->should_complete = true;
-}
-
-BlockJobDriver test_job_driver = {
-    .job_driver = {
-        .instance_size  = sizeof(TestBlockJob),
-        .free           = block_job_free,
-        .user_resume    = block_job_user_resume,
-        .drain          = block_job_drain,
-        .run            = test_job_run,
-        .complete       = test_job_complete,
-        .prepare        = test_job_prepare,
-        .commit         = test_job_commit,
-        .abort          = test_job_abort,
-    },
-};
-
-enum test_job_result {
-    TEST_JOB_SUCCESS,
-    TEST_JOB_FAIL_RUN,
-    TEST_JOB_FAIL_PREPARE,
-};
-
-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,
-                                            bool use_iothread,
-                                            enum test_job_result result,
-                                            enum test_job_drain_node drain_node)
-{
-    BlockBackend *blk_src, *blk_target;
-    BlockDriverState *src, *src_backing, *src_overlay, *target, *drain_bs;
-    BlockJob *job;
-    TestBlockJob *tjob;
-    IOThread *iothread = NULL;
-    AioContext *ctx;
-    int ret;
-
-    src = bdrv_new_open_driver(&bdrv_test, "source", BDRV_O_RDWR,
-                               &error_abort);
-    src_backing = bdrv_new_open_driver(&bdrv_test, "source-backing",
-                                       BDRV_O_RDWR, &error_abort);
-    src_overlay = bdrv_new_open_driver(&bdrv_test, "source-overlay",
-                                       BDRV_O_RDWR, &error_abort);
-
-    bdrv_set_backing_hd(src_overlay, src, &error_abort);
-    bdrv_unref(src);
-    bdrv_set_backing_hd(src, src_backing, &error_abort);
-    bdrv_unref(src_backing);
-
-    blk_src = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
-    blk_insert_bs(blk_src, src_overlay, &error_abort);
-
-    switch (drain_node) {
-    case TEST_JOB_DRAIN_SRC:
-        drain_bs = src;
-        break;
-    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();
-    }
-
-    if (use_iothread) {
-        iothread = iothread_new();
-        ctx = iothread_get_aio_context(iothread);
-        blk_set_aio_context(blk_src, ctx, &error_abort);
-    } else {
-        ctx = qemu_get_aio_context();
-    }
-
-    target = bdrv_new_open_driver(&bdrv_test, "target", BDRV_O_RDWR,
-                                  &error_abort);
-    blk_target = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
-    blk_insert_bs(blk_target, target, &error_abort);
-    blk_set_allow_aio_context_change(blk_target, true);
-
-    aio_context_acquire(ctx);
-    tjob = block_job_create("job0", &test_job_driver, NULL, src,
-                            0, BLK_PERM_ALL,
-                            0, 0, NULL, NULL, &error_abort);
-    job = &tjob->common;
-    block_job_add_bdrv(job, "target", target, 0, BLK_PERM_ALL, &error_abort);
-
-    switch (result) {
-    case TEST_JOB_SUCCESS:
-        break;
-    case TEST_JOB_FAIL_RUN:
-        tjob->run_ret = -EIO;
-        break;
-    case TEST_JOB_FAIL_PREPARE:
-        tjob->prepare_ret = -EIO;
-        break;
-    }
-
-    job_start(&job->job);
-    aio_context_release(ctx);
-
-    if (use_iothread) {
-        /* job_co_entry() is run in the I/O thread, wait for the actual job
-         * code to start (we don't want to catch the job in the pause point in
-         * job_co_entry(). */
-        while (!tjob->running) {
-            aio_poll(qemu_get_aio_context(), false);
-        }
-    }
-
-    g_assert_cmpint(job->job.pause_count, ==, 0);
-    g_assert_false(job->job.paused);
-    g_assert_true(tjob->running);
-    g_assert_true(job->job.busy); /* We're in qemu_co_sleep_ns() */
-
-    do_drain_begin_unlocked(drain_type, drain_bs);
-
-    if (drain_type == BDRV_DRAIN_ALL) {
-        /* bdrv_drain_all() drains both src and target */
-        g_assert_cmpint(job->job.pause_count, ==, 2);
-    } else {
-        g_assert_cmpint(job->job.pause_count, ==, 1);
-    }
-    g_assert_true(job->job.paused);
-    g_assert_false(job->job.busy); /* The job is paused */
-
-    do_drain_end_unlocked(drain_type, drain_bs);
-
-    if (use_iothread) {
-        /* paused is reset in the I/O thread, wait for it */
-        while (job->job.paused) {
-            aio_poll(qemu_get_aio_context(), false);
-        }
-    }
-
-    g_assert_cmpint(job->job.pause_count, ==, 0);
-    g_assert_false(job->job.paused);
-    g_assert_true(job->job.busy); /* We're in qemu_co_sleep_ns() */
-
-    do_drain_begin_unlocked(drain_type, target);
-
-    if (drain_type == BDRV_DRAIN_ALL) {
-        /* bdrv_drain_all() drains both src and target */
-        g_assert_cmpint(job->job.pause_count, ==, 2);
-    } else {
-        g_assert_cmpint(job->job.pause_count, ==, 1);
-    }
-    g_assert_true(job->job.paused);
-    g_assert_false(job->job.busy); /* The job is paused */
-
-    do_drain_end_unlocked(drain_type, target);
-
-    if (use_iothread) {
-        /* paused is reset in the I/O thread, wait for it */
-        while (job->job.paused) {
-            aio_poll(qemu_get_aio_context(), false);
-        }
-    }
-
-    g_assert_cmpint(job->job.pause_count, ==, 0);
-    g_assert_false(job->job.paused);
-    g_assert_true(job->job.busy); /* We're in qemu_co_sleep_ns() */
-
-    aio_context_acquire(ctx);
-    ret = job_complete_sync(&job->job, &error_abort);
-    g_assert_cmpint(ret, ==, (result == TEST_JOB_SUCCESS ? 0 : -EIO));
-
-    if (use_iothread) {
-        blk_set_aio_context(blk_src, qemu_get_aio_context(), &error_abort);
-        assert(blk_get_aio_context(blk_target) == qemu_get_aio_context());
-    }
-    aio_context_release(ctx);
-
-    blk_unref(blk_src);
-    blk_unref(blk_target);
-    bdrv_unref(src_overlay);
-    bdrv_unref(target);
-
-    if (iothread) {
-        iothread_join(iothread);
-    }
-}
-
-static void test_blockjob_common(enum drain_type drain_type, bool use_iothread,
-                                 enum test_job_result result)
-{
-    test_blockjob_common_drain_node(drain_type, use_iothread, result,
-                                    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)
-{
-    test_blockjob_common(BDRV_DRAIN_ALL, false, TEST_JOB_SUCCESS);
-}
-
-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);
-    test_blockjob_common(BDRV_DRAIN_ALL, false, TEST_JOB_FAIL_PREPARE);
-}
-
-static void test_blockjob_error_drain(void)
-{
-    test_blockjob_common(BDRV_DRAIN, false, TEST_JOB_FAIL_RUN);
-    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);
-}
-
-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);
-    test_blockjob_common(BDRV_DRAIN_ALL, true, TEST_JOB_FAIL_PREPARE);
-}
-
-static void test_blockjob_iothread_error_drain(void)
-{
-    test_blockjob_common(BDRV_DRAIN, true, TEST_JOB_FAIL_RUN);
-    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;
-} BDRVTestTopState;
-
-static void bdrv_test_top_close(BlockDriverState *bs)
-{
-    BdrvChild *c, *next_c;
-    QLIST_FOREACH_SAFE(c, &bs->children, next, next_c) {
-        bdrv_unref_child(bs, c);
-    }
-}
-
-static int coroutine_fn bdrv_test_top_co_preadv(BlockDriverState *bs,
-                                                uint64_t offset, uint64_t bytes,
-                                                QEMUIOVector *qiov, int flags)
-{
-    BDRVTestTopState *tts = bs->opaque;
-    return bdrv_co_preadv(tts->wait_child, offset, bytes, qiov, flags);
-}
-
-static BlockDriver bdrv_test_top_driver = {
-    .format_name            = "test_top_driver",
-    .instance_size          = sizeof(BDRVTestTopState),
-
-    .bdrv_close             = bdrv_test_top_close,
-    .bdrv_co_preadv         = bdrv_test_top_co_preadv,
-
-    .bdrv_child_perm        = bdrv_format_default_perms,
-};
-
-typedef struct TestCoDeleteByDrainData {
-    BlockBackend *blk;
-    bool detach_instead_of_delete;
-    bool done;
-} TestCoDeleteByDrainData;
-
-static void coroutine_fn test_co_delete_by_drain(void *opaque)
-{
-    TestCoDeleteByDrainData *dbdd = opaque;
-    BlockBackend *blk = dbdd->blk;
-    BlockDriverState *bs = blk_bs(blk);
-    BDRVTestTopState *tts = bs->opaque;
-    void *buffer = g_malloc(65536);
-    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buffer, 65536);
-
-    /* Pretend some internal write operation from parent to child.
-     * Important: We have to read from the child, not from the parent!
-     * Draining works by first propagating it all up the tree to the
-     * root and then waiting for drainage from root to the leaves
-     * (protocol nodes).  If we have a request waiting on the root,
-     * everything will be drained before we go back down the tree, but
-     * we do not want that.  We want to be in the middle of draining
-     * when this following requests returns. */
-    bdrv_co_preadv(tts->wait_child, 0, 65536, &qiov, 0);
-
-    g_assert_cmpint(bs->refcnt, ==, 1);
-
-    if (!dbdd->detach_instead_of_delete) {
-        blk_unref(blk);
-    } else {
-        BdrvChild *c, *next_c;
-        QLIST_FOREACH_SAFE(c, &bs->children, next, next_c) {
-            bdrv_unref_child(bs, c);
-        }
-    }
-
-    dbdd->done = true;
-    g_free(buffer);
-}
-
-/**
- * Test what happens when some BDS has some children, you drain one of
- * them and this results in the BDS being deleted.
- *
- * If @detach_instead_of_delete is set, the BDS is not going to be
- * deleted but will only detach all of its children.
- */
-static void do_test_delete_by_drain(bool detach_instead_of_delete,
-                                    enum drain_type drain_type)
-{
-    BlockBackend *blk;
-    BlockDriverState *bs, *child_bs, *null_bs;
-    BDRVTestTopState *tts;
-    TestCoDeleteByDrainData dbdd;
-    Coroutine *co;
-
-    bs = bdrv_new_open_driver(&bdrv_test_top_driver, "top", BDRV_O_RDWR,
-                              &error_abort);
-    bs->total_sectors = 65536 >> BDRV_SECTOR_BITS;
-    tts = bs->opaque;
-
-    null_bs = bdrv_open("null-co://", NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL,
-                        &error_abort);
-    bdrv_attach_child(bs, null_bs, "null-child", &child_file, &error_abort);
-
-    /* This child will be the one to pass to requests through to, and
-     * it will stall until a drain occurs */
-    child_bs = bdrv_new_open_driver(&bdrv_test, "child", BDRV_O_RDWR,
-                                    &error_abort);
-    child_bs->total_sectors = 65536 >> BDRV_SECTOR_BITS;
-    /* Takes our reference to child_bs */
-    tts->wait_child = bdrv_attach_child(bs, child_bs, "wait-child", &child_file,
-                                        &error_abort);
-
-    /* This child is just there to be deleted
-     * (for detach_instead_of_delete == true) */
-    null_bs = bdrv_open("null-co://", NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL,
-                        &error_abort);
-    bdrv_attach_child(bs, null_bs, "null-child", &child_file, &error_abort);
-
-    blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
-    blk_insert_bs(blk, bs, &error_abort);
-
-    /* Referenced by blk now */
-    bdrv_unref(bs);
-
-    g_assert_cmpint(bs->refcnt, ==, 1);
-    g_assert_cmpint(child_bs->refcnt, ==, 1);
-    g_assert_cmpint(null_bs->refcnt, ==, 1);
-
-
-    dbdd = (TestCoDeleteByDrainData){
-        .blk = blk,
-        .detach_instead_of_delete = detach_instead_of_delete,
-        .done = false,
-    };
-    co = qemu_coroutine_create(test_co_delete_by_drain, &dbdd);
-    qemu_coroutine_enter(co);
-
-    /* Drain the child while the read operation is still pending.
-     * This should result in the operation finishing and
-     * test_co_delete_by_drain() resuming.  Thus, @bs will be deleted
-     * and the coroutine will exit while this drain operation is still
-     * in progress. */
-    switch (drain_type) {
-    case BDRV_DRAIN:
-        bdrv_ref(child_bs);
-        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();
-        break;
-    default:
-        g_assert_not_reached();
-    }
-
-    while (!dbdd.done) {
-        aio_poll(qemu_get_aio_context(), true);
-    }
-
-    if (detach_instead_of_delete) {
-        /* Here, the reference has not passed over to the coroutine,
-         * so we have to delete the BB ourselves */
-        blk_unref(blk);
-    }
-}
-
-static void test_delete_by_drain(void)
-{
-    do_test_delete_by_drain(false, BDRV_DRAIN);
-}
-
-static void test_detach_by_drain_all(void)
-{
-    do_test_delete_by_drain(true, BDRV_DRAIN_ALL);
-}
-
-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;
-    BdrvChild *child_b;
-    BlockDriverState *c;
-    BdrvChild *child_c;
-    bool by_parent_cb;
-};
-static struct detach_by_parent_data detach_by_parent_data;
-
-static void detach_indirect_bh(void *opaque)
-{
-    struct detach_by_parent_data *data = opaque;
-
-    bdrv_unref_child(data->parent_b, data->child_b);
-
-    bdrv_ref(data->c);
-    data->child_c = bdrv_attach_child(data->parent_b, data->c, "PB-C",
-                                      &child_file, &error_abort);
-}
-
-static void detach_by_parent_aio_cb(void *opaque, int ret)
-{
-    struct detach_by_parent_data *data = &detach_by_parent_data;
-
-    g_assert_cmpint(ret, ==, 0);
-    if (data->by_parent_cb) {
-        detach_indirect_bh(data);
-    }
-}
-
-static void detach_by_driver_cb_drained_begin(BdrvChild *child)
-{
-    aio_bh_schedule_oneshot(qemu_get_current_aio_context(),
-                            detach_indirect_bh, &detach_by_parent_data);
-    child_file.drained_begin(child);
-}
-
-static BdrvChildRole detach_by_driver_cb_role;
-
-/*
- * Initial graph:
- *
- * PA     PB
- *    \ /   \
- *     A     B     C
- *
- * by_parent_cb == true:  Test that parent callbacks don't poll
- *
- *     PA has a pending write request whose callback changes the child nodes of
- *     PB: It removes B and adds C instead. The subtree of PB is drained, which
- *     will indirectly drain the write request, too.
- *
- * by_parent_cb == false: Test that bdrv_drain_invoke() doesn't poll
- *
- *     PA's BdrvChildRole has a .drained_begin callback that schedules a BH
- *     that does the same graph change. If bdrv_drain_invoke() calls it, the
- *     state is messed up, but if it is only polled in the single
- *     BDRV_POLL_WHILE() at the end of the drain, this should work fine.
- */
-static void test_detach_indirect(bool by_parent_cb)
-{
-    BlockBackend *blk;
-    BlockDriverState *parent_a, *parent_b, *a, *b, *c;
-    BdrvChild *child_a, *child_b;
-    BlockAIOCB *acb;
-
-    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, NULL, 0);
-
-    if (!by_parent_cb) {
-        detach_by_driver_cb_role = child_file;
-        detach_by_driver_cb_role.drained_begin =
-            detach_by_driver_cb_drained_begin;
-    }
-
-    /* Create all involved nodes */
-    parent_a = bdrv_new_open_driver(&bdrv_test, "parent-a", BDRV_O_RDWR,
-                                    &error_abort);
-    parent_b = bdrv_new_open_driver(&bdrv_test, "parent-b", 0,
-                                    &error_abort);
-
-    a = bdrv_new_open_driver(&bdrv_test, "a", BDRV_O_RDWR, &error_abort);
-    b = bdrv_new_open_driver(&bdrv_test, "b", BDRV_O_RDWR, &error_abort);
-    c = bdrv_new_open_driver(&bdrv_test, "c", BDRV_O_RDWR, &error_abort);
-
-    /* blk is a BB for parent-a */
-    blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
-    blk_insert_bs(blk, parent_a, &error_abort);
-    bdrv_unref(parent_a);
-
-    /* If we want to get bdrv_drain_invoke() to call aio_poll(), the driver
-     * callback must not return immediately. */
-    if (!by_parent_cb) {
-        BDRVTestState *s = parent_a->opaque;
-        s->sleep_in_drain_begin = true;
-    }
-
-    /* Set child relationships */
-    bdrv_ref(b);
-    bdrv_ref(a);
-    child_b = bdrv_attach_child(parent_b, b, "PB-B", &child_file, &error_abort);
-    child_a = bdrv_attach_child(parent_b, a, "PB-A", &child_backing, &error_abort);
-
-    bdrv_ref(a);
-    bdrv_attach_child(parent_a, a, "PA-A",
-                      by_parent_cb ? &child_file : &detach_by_driver_cb_role,
-                      &error_abort);
-
-    g_assert_cmpint(parent_a->refcnt, ==, 1);
-    g_assert_cmpint(parent_b->refcnt, ==, 1);
-    g_assert_cmpint(a->refcnt, ==, 3);
-    g_assert_cmpint(b->refcnt, ==, 2);
-    g_assert_cmpint(c->refcnt, ==, 1);
-
-    g_assert(QLIST_FIRST(&parent_b->children) == child_a);
-    g_assert(QLIST_NEXT(child_a, next) == child_b);
-    g_assert(QLIST_NEXT(child_b, next) == NULL);
-
-    /* Start the evil write request */
-    detach_by_parent_data = (struct detach_by_parent_data) {
-        .parent_b = parent_b,
-        .child_b = child_b,
-        .c = c,
-        .by_parent_cb = by_parent_cb,
-    };
-    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);
-
-    g_assert(detach_by_parent_data.child_c != NULL);
-
-    g_assert_cmpint(parent_a->refcnt, ==, 1);
-    g_assert_cmpint(parent_b->refcnt, ==, 1);
-    g_assert_cmpint(a->refcnt, ==, 3);
-    g_assert_cmpint(b->refcnt, ==, 1);
-    g_assert_cmpint(c->refcnt, ==, 2);
-
-    g_assert(QLIST_FIRST(&parent_b->children) == detach_by_parent_data.child_c);
-    g_assert(QLIST_NEXT(detach_by_parent_data.child_c, next) == child_a);
-    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(a->quiesce_counter, ==, 1);
-    g_assert_cmpint(b->quiesce_counter, ==, 0);
-    g_assert_cmpint(c->quiesce_counter, ==, 1);
-
-    bdrv_subtree_drained_end(parent_b);
-
-    bdrv_unref(parent_b);
-    blk_unref(blk);
-
-    g_assert_cmpint(a->refcnt, ==, 1);
-    g_assert_cmpint(b->refcnt, ==, 1);
-    g_assert_cmpint(c->refcnt, ==, 1);
-    bdrv_unref(a);
-    bdrv_unref(b);
-    bdrv_unref(c);
-}
-
-static void test_detach_by_parent_cb(void)
-{
-    test_detach_indirect(true);
-}
-
-static void test_detach_by_driver_cb(void)
-{
-    test_detach_indirect(false);
-}
-
-static void test_append_to_drained(void)
-{
-    BlockBackend *blk;
-    BlockDriverState *base, *overlay;
-    BDRVTestState *base_s, *overlay_s;
-
-    blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
-    base = bdrv_new_open_driver(&bdrv_test, "base", BDRV_O_RDWR, &error_abort);
-    base_s = base->opaque;
-    blk_insert_bs(blk, base, &error_abort);
-
-    overlay = bdrv_new_open_driver(&bdrv_test, "overlay", BDRV_O_RDWR,
-                                   &error_abort);
-    overlay_s = overlay->opaque;
-
-    do_drain_begin(BDRV_DRAIN, base);
-    g_assert_cmpint(base->quiesce_counter, ==, 1);
-    g_assert_cmpint(base_s->drain_count, ==, 1);
-    g_assert_cmpint(base->in_flight, ==, 0);
-
-    /* Takes ownership of overlay, so we don't have to unref it later */
-    bdrv_append(overlay, base, &error_abort);
-    g_assert_cmpint(base->in_flight, ==, 0);
-    g_assert_cmpint(overlay->in_flight, ==, 0);
-
-    g_assert_cmpint(base->quiesce_counter, ==, 1);
-    g_assert_cmpint(base_s->drain_count, ==, 1);
-    g_assert_cmpint(overlay->quiesce_counter, ==, 1);
-    g_assert_cmpint(overlay_s->drain_count, ==, 1);
-
-    do_drain_end(BDRV_DRAIN, base);
-
-    g_assert_cmpint(base->quiesce_counter, ==, 0);
-    g_assert_cmpint(base_s->drain_count, ==, 0);
-    g_assert_cmpint(overlay->quiesce_counter, ==, 0);
-    g_assert_cmpint(overlay_s->drain_count, ==, 0);
-
-    bdrv_unref(base);
-    blk_unref(blk);
-}
-
-static void test_set_aio_context(void)
-{
-    BlockDriverState *bs;
-    IOThread *a = iothread_new();
-    IOThread *b = iothread_new();
-    AioContext *ctx_a = iothread_get_aio_context(a);
-    AioContext *ctx_b = iothread_get_aio_context(b);
-
-    bs = bdrv_new_open_driver(&bdrv_test, "test-node", BDRV_O_RDWR,
-                              &error_abort);
-
-    bdrv_drained_begin(bs);
-    bdrv_set_aio_context(bs, ctx_a);
-
-    aio_context_acquire(ctx_a);
-    bdrv_drained_end(bs);
-
-    bdrv_drained_begin(bs);
-    bdrv_set_aio_context(bs, ctx_b);
-    aio_context_release(ctx_a);
-    aio_context_acquire(ctx_b);
-    bdrv_set_aio_context(bs, qemu_get_aio_context());
-    aio_context_release(ctx_b);
-    bdrv_drained_end(bs);
-
-    bdrv_unref(bs);
-    iothread_join(a);
-    iothread_join(b);
-}
-
-int main(int argc, char **argv)
-{
-    int ret;
-
-    bdrv_init();
-    qemu_init_main_loop(&error_abort);
-
-    g_test_init(&argc, &argv, NULL);
-    qemu_event_init(&done_event, false);
-
-    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);
-
-    g_test_add_func("/bdrv-drain/attach/drain", test_append_to_drained);
-
-    g_test_add_func("/bdrv-drain/set_aio_context", test_set_aio_context);
-
-    ret = g_test_run();
-    qemu_event_destroy(&done_event);
-    return ret;
-}