tests/test-bdrv-drain.c

   1 /*
   2  * Block node draining tests
   3  *
   4  * Copyright (c) 2017 Kevin Wolf <[email protected]>
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24
  25 #include "qemu/osdep.h"
  26 #include "block/block.h"
  27 #include "block/blockjob_int.h"
  28 #include "sysemu/block-backend.h"
  29 #include "qapi/error.h"
  30 #include "iothread.h"
  31
  32 static QemuEvent done_event;
  33
  34 typedef struct BDRVTestState {
  35     int drain_count;
  36     AioContext *bh_indirection_ctx;
  37     bool sleep_in_drain_begin;
  38 } BDRVTestState;
  39
  40 static void coroutine_fn bdrv_test_co_drain_begin(BlockDriverState *bs)
  41 {
  42     BDRVTestState *s = bs->opaque;
  43     s->drain_count++;
  44     if (s->sleep_in_drain_begin) {
  45         qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, 100000);
  46     }
  47 }
  48
  49 static void coroutine_fn bdrv_test_co_drain_end(BlockDriverState *bs)
  50 {
  51     BDRVTestState *s = bs->opaque;
  52     s->drain_count--;
  53 }
  54
  55 static void bdrv_test_close(BlockDriverState *bs)
  56 {
  57     BDRVTestState *s = bs->opaque;
  58     g_assert_cmpint(s->drain_count, >, 0);
  59 }
  60
  61 static void co_reenter_bh(void *opaque)
  62 {
  63     aio_co_wake(opaque);
  64 }
  65
  66 static int coroutine_fn bdrv_test_co_preadv(BlockDriverState *bs,
  67                                             uint64_t offset, uint64_t bytes,
  68                                             QEMUIOVector *qiov, int flags)
  69 {
  70     BDRVTestState *s = bs->opaque;
  71
  72     /* We want this request to stay until the polling loop in drain waits for
  73      * it to complete. We need to sleep a while as bdrv_drain_invoke() comes
  74      * first and polls its result, too, but it shouldn't accidentally complete
  75      * this request yet. */
  76     qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, 100000);
  77
  78     if (s->bh_indirection_ctx) {
  79         aio_bh_schedule_oneshot(s->bh_indirection_ctx, co_reenter_bh,
  80                                 qemu_coroutine_self());
  81         qemu_coroutine_yield();
  82     }
  83
  84     return 0;
  85 }
  86
  87 static void bdrv_test_child_perm(BlockDriverState *bs, BdrvChild *c,
  88                                  const BdrvChildRole *role,
  89                                  BlockReopenQueue *reopen_queue,
  90                                  uint64_t perm, uint64_t shared,
  91                                  uint64_t *nperm, uint64_t *nshared)
  92 {
  93     /* bdrv_format_default_perms() accepts only these two, so disguise
  94      * detach_by_driver_cb_role as one of them. */
  95     if (role != &child_file && role != &child_backing) {
  96         role = &child_file;
  97     }
  98
  99     bdrv_format_default_perms(bs, c, role, reopen_queue, perm, shared,
 100                               nperm, nshared);
 101 }
 102
 103 static BlockDriver bdrv_test = {
 104     .format_name            = "test",
 105     .instance_size          = sizeof(BDRVTestState),
 106
 107     .bdrv_close             = bdrv_test_close,
 108     .bdrv_co_preadv         = bdrv_test_co_preadv,
 109
 110     .bdrv_co_drain_begin    = bdrv_test_co_drain_begin,
 111     .bdrv_co_drain_end      = bdrv_test_co_drain_end,
 112
 113     .bdrv_child_perm        = bdrv_test_child_perm,
 114 };
 115
 116 static void aio_ret_cb(void *opaque, int ret)
 117 {
 118     int *aio_ret = opaque;
 119     *aio_ret = ret;
 120 }
 121
 122 typedef struct CallInCoroutineData {
 123     void (*entry)(void);
 124     bool done;
 125 } CallInCoroutineData;
 126
 127 static coroutine_fn void call_in_coroutine_entry(void *opaque)
 128 {
 129     CallInCoroutineData *data = opaque;
 130
 131     data->entry();
 132     data->done = true;
 133 }
 134
 135 static void call_in_coroutine(void (*entry)(void))
 136 {
 137     Coroutine *co;
 138     CallInCoroutineData data = {
 139         .entry  = entry,
 140         .done   = false,
 141     };
 142
 143     co = qemu_coroutine_create(call_in_coroutine_entry, &data);
 144     qemu_coroutine_enter(co);
 145     while (!data.done) {
 146         aio_poll(qemu_get_aio_context(), true);
 147     }
 148 }
 149
 150 enum drain_type {
 151     BDRV_DRAIN_ALL,
 152     BDRV_DRAIN,
 153     BDRV_SUBTREE_DRAIN,
 154     DRAIN_TYPE_MAX,
 155 };
 156
 157 static void do_drain_begin(enum drain_type drain_type, BlockDriverState *bs)
 158 {
 159     switch (drain_type) {
 160     case BDRV_DRAIN_ALL:        bdrv_drain_all_begin(); break;
 161     case BDRV_DRAIN:            bdrv_drained_begin(bs); break;
 162     case BDRV_SUBTREE_DRAIN:    bdrv_subtree_drained_begin(bs); break;
 163     default:                    g_assert_not_reached();
 164     }
 165 }
 166
 167 static void do_drain_end(enum drain_type drain_type, BlockDriverState *bs)
 168 {
 169     switch (drain_type) {
 170     case BDRV_DRAIN_ALL:        bdrv_drain_all_end(); break;
 171     case BDRV_DRAIN:            bdrv_drained_end(bs); break;
 172     case BDRV_SUBTREE_DRAIN:    bdrv_subtree_drained_end(bs); break;
 173     default:                    g_assert_not_reached();
 174     }
 175 }
 176
 177 static void do_drain_begin_unlocked(enum drain_type drain_type, BlockDriverState *bs)
 178 {
 179     if (drain_type != BDRV_DRAIN_ALL) {
 180         aio_context_acquire(bdrv_get_aio_context(bs));
 181     }
 182     do_drain_begin(drain_type, bs);
 183     if (drain_type != BDRV_DRAIN_ALL) {
 184         aio_context_release(bdrv_get_aio_context(bs));
 185     }
 186 }
 187
 188 static void do_drain_end_unlocked(enum drain_type drain_type, BlockDriverState *bs)
 189 {
 190     if (drain_type != BDRV_DRAIN_ALL) {
 191         aio_context_acquire(bdrv_get_aio_context(bs));
 192     }
 193     do_drain_end(drain_type, bs);
 194     if (drain_type != BDRV_DRAIN_ALL) {
 195         aio_context_release(bdrv_get_aio_context(bs));
 196     }
 197 }
 198
 199 static void test_drv_cb_common(enum drain_type drain_type, bool recursive)
 200 {
 201     BlockBackend *blk;
 202     BlockDriverState *bs, *backing;
 203     BDRVTestState *s, *backing_s;
 204     BlockAIOCB *acb;
 205     int aio_ret;
 206
 207     QEMUIOVector qiov;
 208     struct iovec iov = {
 209         .iov_base = NULL,
 210         .iov_len = 0,
 211     };
 212     qemu_iovec_init_external(&qiov, &iov, 1);
 213
 214     blk = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
 215     bs = bdrv_new_open_driver(&bdrv_test, "test-node", BDRV_O_RDWR,
 216                               &error_abort);
 217     s = bs->opaque;
 218     blk_insert_bs(blk, bs, &error_abort);
 219
 220     backing = bdrv_new_open_driver(&bdrv_test, "backing", 0, &error_abort);
 221     backing_s = backing->opaque;
 222     bdrv_set_backing_hd(bs, backing, &error_abort);
 223
 224     /* Simple bdrv_drain_all_begin/end pair, check that CBs are called */
 225     g_assert_cmpint(s->drain_count, ==, 0);
 226     g_assert_cmpint(backing_s->drain_count, ==, 0);
 227
 228     do_drain_begin(drain_type, bs);
 229
 230     g_assert_cmpint(s->drain_count, ==, 1);
 231     g_assert_cmpint(backing_s->drain_count, ==, !!recursive);
 232
 233     do_drain_end(drain_type, bs);
 234
 235     g_assert_cmpint(s->drain_count, ==, 0);
 236     g_assert_cmpint(backing_s->drain_count, ==, 0);
 237
 238     /* Now do the same while a request is pending */
 239     aio_ret = -EINPROGRESS;
 240     acb = blk_aio_preadv(blk, 0, &qiov, 0, aio_ret_cb, &aio_ret);
 241     g_assert(acb != NULL);
 242     g_assert_cmpint(aio_ret, ==, -EINPROGRESS);
 243
 244     g_assert_cmpint(s->drain_count, ==, 0);
 245     g_assert_cmpint(backing_s->drain_count, ==, 0);
 246
 247     do_drain_begin(drain_type, bs);
 248
 249     g_assert_cmpint(aio_ret, ==, 0);
 250     g_assert_cmpint(s->drain_count, ==, 1);
 251     g_assert_cmpint(backing_s->drain_count, ==, !!recursive);
 252
 253     do_drain_end(drain_type, bs);
 254
 255     g_assert_cmpint(s->drain_count, ==, 0);
 256     g_assert_cmpint(backing_s->drain_count, ==, 0);
 257
 258     bdrv_unref(backing);
 259     bdrv_unref(bs);
 260     blk_unref(blk);
 261 }
 262
 263 static void test_drv_cb_drain_all(void)
 264 {
 265     test_drv_cb_common(BDRV_DRAIN_ALL, true);
 266 }
 267
 268 static void test_drv_cb_drain(void)
 269 {
 270     test_drv_cb_common(BDRV_DRAIN, false);
 271 }
 272
 273 static void test_drv_cb_drain_subtree(void)
 274 {
 275     test_drv_cb_common(BDRV_SUBTREE_DRAIN, true);
 276 }
 277
 278 static void test_drv_cb_co_drain_all(void)
 279 {
 280     call_in_coroutine(test_drv_cb_drain_all);
 281 }
 282
 283 static void test_drv_cb_co_drain(void)
 284 {
 285     call_in_coroutine(test_drv_cb_drain);
 286 }
 287
 288 static void test_drv_cb_co_drain_subtree(void)
 289 {
 290     call_in_coroutine(test_drv_cb_drain_subtree);
 291 }
 292
 293 static void test_quiesce_common(enum drain_type drain_type, bool recursive)
 294 {
 295     BlockBackend *blk;
 296     BlockDriverState *bs, *backing;
 297
 298     blk = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
 299     bs = bdrv_new_open_driver(&bdrv_test, "test-node", BDRV_O_RDWR,
 300                               &error_abort);
 301     blk_insert_bs(blk, bs, &error_abort);
 302
 303     backing = bdrv_new_open_driver(&bdrv_test, "backing", 0, &error_abort);
 304     bdrv_set_backing_hd(bs, backing, &error_abort);
 305
 306     g_assert_cmpint(bs->quiesce_counter, ==, 0);
 307     g_assert_cmpint(backing->quiesce_counter, ==, 0);
 308
 309     do_drain_begin(drain_type, bs);
 310
 311     g_assert_cmpint(bs->quiesce_counter, ==, 1);
 312     g_assert_cmpint(backing->quiesce_counter, ==, !!recursive);
 313
 314     do_drain_end(drain_type, bs);
 315
 316     g_assert_cmpint(bs->quiesce_counter, ==, 0);
 317     g_assert_cmpint(backing->quiesce_counter, ==, 0);
 318
 319     bdrv_unref(backing);
 320     bdrv_unref(bs);
 321     blk_unref(blk);
 322 }
 323
 324 static void test_quiesce_drain_all(void)
 325 {
 326     test_quiesce_common(BDRV_DRAIN_ALL, true);
 327 }
 328
 329 static void test_quiesce_drain(void)
 330 {
 331     test_quiesce_common(BDRV_DRAIN, false);
 332 }
 333
 334 static void test_quiesce_drain_subtree(void)
 335 {
 336     test_quiesce_common(BDRV_SUBTREE_DRAIN, true);
 337 }
 338
 339 static void test_quiesce_co_drain_all(void)
 340 {
 341     call_in_coroutine(test_quiesce_drain_all);
 342 }
 343
 344 static void test_quiesce_co_drain(void)
 345 {
 346     call_in_coroutine(test_quiesce_drain);
 347 }
 348
 349 static void test_quiesce_co_drain_subtree(void)
 350 {
 351     call_in_coroutine(test_quiesce_drain_subtree);
 352 }
 353
 354 static void test_nested(void)
 355 {
 356     BlockBackend *blk;
 357     BlockDriverState *bs, *backing;
 358     BDRVTestState *s, *backing_s;
 359     enum drain_type outer, inner;
 360
 361     blk = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
 362     bs = bdrv_new_open_driver(&bdrv_test, "test-node", BDRV_O_RDWR,
 363                               &error_abort);
 364     s = bs->opaque;
 365     blk_insert_bs(blk, bs, &error_abort);
 366
 367     backing = bdrv_new_open_driver(&bdrv_test, "backing", 0, &error_abort);
 368     backing_s = backing->opaque;
 369     bdrv_set_backing_hd(bs, backing, &error_abort);
 370
 371     for (outer = 0; outer < DRAIN_TYPE_MAX; outer++) {
 372         for (inner = 0; inner < DRAIN_TYPE_MAX; inner++) {
 373             int backing_quiesce = (outer != BDRV_DRAIN) +
 374                                   (inner != BDRV_DRAIN);
 375
 376             g_assert_cmpint(bs->quiesce_counter, ==, 0);
 377             g_assert_cmpint(backing->quiesce_counter, ==, 0);
 378             g_assert_cmpint(s->drain_count, ==, 0);
 379             g_assert_cmpint(backing_s->drain_count, ==, 0);
 380
 381             do_drain_begin(outer, bs);
 382             do_drain_begin(inner, bs);
 383
 384             g_assert_cmpint(bs->quiesce_counter, ==, 2);
 385             g_assert_cmpint(backing->quiesce_counter, ==, backing_quiesce);
 386             g_assert_cmpint(s->drain_count, ==, 2);
 387             g_assert_cmpint(backing_s->drain_count, ==, backing_quiesce);
 388
 389             do_drain_end(inner, bs);
 390             do_drain_end(outer, bs);
 391
 392             g_assert_cmpint(bs->quiesce_counter, ==, 0);
 393             g_assert_cmpint(backing->quiesce_counter, ==, 0);
 394             g_assert_cmpint(s->drain_count, ==, 0);
 395             g_assert_cmpint(backing_s->drain_count, ==, 0);
 396         }
 397     }
 398
 399     bdrv_unref(backing);
 400     bdrv_unref(bs);
 401     blk_unref(blk);
 402 }
 403
 404 static void test_multiparent(void)
 405 {
 406     BlockBackend *blk_a, *blk_b;
 407     BlockDriverState *bs_a, *bs_b, *backing;
 408     BDRVTestState *a_s, *b_s, *backing_s;
 409
 410     blk_a = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
 411     bs_a = bdrv_new_open_driver(&bdrv_test, "test-node-a", BDRV_O_RDWR,
 412                                 &error_abort);
 413     a_s = bs_a->opaque;
 414     blk_insert_bs(blk_a, bs_a, &error_abort);
 415
 416     blk_b = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
 417     bs_b = bdrv_new_open_driver(&bdrv_test, "test-node-b", BDRV_O_RDWR,
 418                                 &error_abort);
 419     b_s = bs_b->opaque;
 420     blk_insert_bs(blk_b, bs_b, &error_abort);
 421
 422     backing = bdrv_new_open_driver(&bdrv_test, "backing", 0, &error_abort);
 423     backing_s = backing->opaque;
 424     bdrv_set_backing_hd(bs_a, backing, &error_abort);
 425     bdrv_set_backing_hd(bs_b, backing, &error_abort);
 426
 427     g_assert_cmpint(bs_a->quiesce_counter, ==, 0);
 428     g_assert_cmpint(bs_b->quiesce_counter, ==, 0);
 429     g_assert_cmpint(backing->quiesce_counter, ==, 0);
 430     g_assert_cmpint(a_s->drain_count, ==, 0);
 431     g_assert_cmpint(b_s->drain_count, ==, 0);
 432     g_assert_cmpint(backing_s->drain_count, ==, 0);
 433
 434     do_drain_begin(BDRV_SUBTREE_DRAIN, bs_a);
 435
 436     g_assert_cmpint(bs_a->quiesce_counter, ==, 1);
 437     g_assert_cmpint(bs_b->quiesce_counter, ==, 1);
 438     g_assert_cmpint(backing->quiesce_counter, ==, 1);
 439     g_assert_cmpint(a_s->drain_count, ==, 1);
 440     g_assert_cmpint(b_s->drain_count, ==, 1);
 441     g_assert_cmpint(backing_s->drain_count, ==, 1);
 442
 443     do_drain_begin(BDRV_SUBTREE_DRAIN, bs_b);
 444
 445     g_assert_cmpint(bs_a->quiesce_counter, ==, 2);
 446     g_assert_cmpint(bs_b->quiesce_counter, ==, 2);
 447     g_assert_cmpint(backing->quiesce_counter, ==, 2);
 448     g_assert_cmpint(a_s->drain_count, ==, 2);
 449     g_assert_cmpint(b_s->drain_count, ==, 2);
 450     g_assert_cmpint(backing_s->drain_count, ==, 2);
 451
 452     do_drain_end(BDRV_SUBTREE_DRAIN, bs_b);
 453
 454     g_assert_cmpint(bs_a->quiesce_counter, ==, 1);
 455     g_assert_cmpint(bs_b->quiesce_counter, ==, 1);
 456     g_assert_cmpint(backing->quiesce_counter, ==, 1);
 457     g_assert_cmpint(a_s->drain_count, ==, 1);
 458     g_assert_cmpint(b_s->drain_count, ==, 1);
 459     g_assert_cmpint(backing_s->drain_count, ==, 1);
 460
 461     do_drain_end(BDRV_SUBTREE_DRAIN, bs_a);
 462
 463     g_assert_cmpint(bs_a->quiesce_counter, ==, 0);
 464     g_assert_cmpint(bs_b->quiesce_counter, ==, 0);
 465     g_assert_cmpint(backing->quiesce_counter, ==, 0);
 466     g_assert_cmpint(a_s->drain_count, ==, 0);
 467     g_assert_cmpint(b_s->drain_count, ==, 0);
 468     g_assert_cmpint(backing_s->drain_count, ==, 0);
 469
 470     bdrv_unref(backing);
 471     bdrv_unref(bs_a);
 472     bdrv_unref(bs_b);
 473     blk_unref(blk_a);
 474     blk_unref(blk_b);
 475 }
 476
 477 static void test_graph_change_drain_subtree(void)
 478 {
 479     BlockBackend *blk_a, *blk_b;
 480     BlockDriverState *bs_a, *bs_b, *backing;
 481     BDRVTestState *a_s, *b_s, *backing_s;
 482
 483     blk_a = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
 484     bs_a = bdrv_new_open_driver(&bdrv_test, "test-node-a", BDRV_O_RDWR,
 485                                 &error_abort);
 486     a_s = bs_a->opaque;
 487     blk_insert_bs(blk_a, bs_a, &error_abort);
 488
 489     blk_b = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
 490     bs_b = bdrv_new_open_driver(&bdrv_test, "test-node-b", BDRV_O_RDWR,
 491                                 &error_abort);
 492     b_s = bs_b->opaque;
 493     blk_insert_bs(blk_b, bs_b, &error_abort);
 494
 495     backing = bdrv_new_open_driver(&bdrv_test, "backing", 0, &error_abort);
 496     backing_s = backing->opaque;
 497     bdrv_set_backing_hd(bs_a, backing, &error_abort);
 498
 499     g_assert_cmpint(bs_a->quiesce_counter, ==, 0);
 500     g_assert_cmpint(bs_b->quiesce_counter, ==, 0);
 501     g_assert_cmpint(backing->quiesce_counter, ==, 0);
 502     g_assert_cmpint(a_s->drain_count, ==, 0);
 503     g_assert_cmpint(b_s->drain_count, ==, 0);
 504     g_assert_cmpint(backing_s->drain_count, ==, 0);
 505
 506     do_drain_begin(BDRV_SUBTREE_DRAIN, bs_a);
 507     do_drain_begin(BDRV_SUBTREE_DRAIN, bs_a);
 508     do_drain_begin(BDRV_SUBTREE_DRAIN, bs_a);
 509     do_drain_begin(BDRV_SUBTREE_DRAIN, bs_b);
 510     do_drain_begin(BDRV_SUBTREE_DRAIN, bs_b);
 511
 512     bdrv_set_backing_hd(bs_b, backing, &error_abort);
 513     g_assert_cmpint(bs_a->quiesce_counter, ==, 5);
 514     g_assert_cmpint(bs_b->quiesce_counter, ==, 5);
 515     g_assert_cmpint(backing->quiesce_counter, ==, 5);
 516     g_assert_cmpint(a_s->drain_count, ==, 5);
 517     g_assert_cmpint(b_s->drain_count, ==, 5);
 518     g_assert_cmpint(backing_s->drain_count, ==, 5);
 519
 520     bdrv_set_backing_hd(bs_b, NULL, &error_abort);
 521     g_assert_cmpint(bs_a->quiesce_counter, ==, 3);
 522     g_assert_cmpint(bs_b->quiesce_counter, ==, 2);
 523     g_assert_cmpint(backing->quiesce_counter, ==, 3);
 524     g_assert_cmpint(a_s->drain_count, ==, 3);
 525     g_assert_cmpint(b_s->drain_count, ==, 2);
 526     g_assert_cmpint(backing_s->drain_count, ==, 3);
 527
 528     bdrv_set_backing_hd(bs_b, backing, &error_abort);
 529     g_assert_cmpint(bs_a->quiesce_counter, ==, 5);
 530     g_assert_cmpint(bs_b->quiesce_counter, ==, 5);
 531     g_assert_cmpint(backing->quiesce_counter, ==, 5);
 532     g_assert_cmpint(a_s->drain_count, ==, 5);
 533     g_assert_cmpint(b_s->drain_count, ==, 5);
 534     g_assert_cmpint(backing_s->drain_count, ==, 5);
 535
 536     do_drain_end(BDRV_SUBTREE_DRAIN, bs_b);
 537     do_drain_end(BDRV_SUBTREE_DRAIN, bs_b);
 538     do_drain_end(BDRV_SUBTREE_DRAIN, bs_a);
 539     do_drain_end(BDRV_SUBTREE_DRAIN, bs_a);
 540     do_drain_end(BDRV_SUBTREE_DRAIN, bs_a);
 541
 542     g_assert_cmpint(bs_a->quiesce_counter, ==, 0);
 543     g_assert_cmpint(bs_b->quiesce_counter, ==, 0);
 544     g_assert_cmpint(backing->quiesce_counter, ==, 0);
 545     g_assert_cmpint(a_s->drain_count, ==, 0);
 546     g_assert_cmpint(b_s->drain_count, ==, 0);
 547     g_assert_cmpint(backing_s->drain_count, ==, 0);
 548
 549     bdrv_unref(backing);
 550     bdrv_unref(bs_a);
 551     bdrv_unref(bs_b);
 552     blk_unref(blk_a);
 553     blk_unref(blk_b);
 554 }
 555
 556 static void test_graph_change_drain_all(void)
 557 {
 558     BlockBackend *blk_a, *blk_b;
 559     BlockDriverState *bs_a, *bs_b;
 560     BDRVTestState *a_s, *b_s;
 561
 562     /* Create node A with a BlockBackend */
 563     blk_a = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
 564     bs_a = bdrv_new_open_driver(&bdrv_test, "test-node-a", BDRV_O_RDWR,
 565                                 &error_abort);
 566     a_s = bs_a->opaque;
 567     blk_insert_bs(blk_a, bs_a, &error_abort);
 568
 569     g_assert_cmpint(bs_a->quiesce_counter, ==, 0);
 570     g_assert_cmpint(a_s->drain_count, ==, 0);
 571
 572     /* Call bdrv_drain_all_begin() */
 573     bdrv_drain_all_begin();
 574
 575     g_assert_cmpint(bs_a->quiesce_counter, ==, 1);
 576     g_assert_cmpint(a_s->drain_count, ==, 1);
 577
 578     /* Create node B with a BlockBackend */
 579     blk_b = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
 580     bs_b = bdrv_new_open_driver(&bdrv_test, "test-node-b", BDRV_O_RDWR,
 581                                 &error_abort);
 582     b_s = bs_b->opaque;
 583     blk_insert_bs(blk_b, bs_b, &error_abort);
 584
 585     g_assert_cmpint(bs_a->quiesce_counter, ==, 1);
 586     g_assert_cmpint(bs_b->quiesce_counter, ==, 1);
 587     g_assert_cmpint(a_s->drain_count, ==, 1);
 588     g_assert_cmpint(b_s->drain_count, ==, 1);
 589
 590     /* Unref and finally delete node A */
 591     blk_unref(blk_a);
 592
 593     g_assert_cmpint(bs_a->quiesce_counter, ==, 1);
 594     g_assert_cmpint(bs_b->quiesce_counter, ==, 1);
 595     g_assert_cmpint(a_s->drain_count, ==, 1);
 596     g_assert_cmpint(b_s->drain_count, ==, 1);
 597
 598     bdrv_unref(bs_a);
 599
 600     g_assert_cmpint(bs_b->quiesce_counter, ==, 1);
 601     g_assert_cmpint(b_s->drain_count, ==, 1);
 602
 603     /* End the drained section */
 604     bdrv_drain_all_end();
 605
 606     g_assert_cmpint(bs_b->quiesce_counter, ==, 0);
 607     g_assert_cmpint(b_s->drain_count, ==, 0);
 608
 609     bdrv_unref(bs_b);
 610     blk_unref(blk_b);
 611 }
 612
 613 struct test_iothread_data {
 614     BlockDriverState *bs;
 615     enum drain_type drain_type;
 616     int *aio_ret;
 617 };
 618
 619 static void test_iothread_drain_entry(void *opaque)
 620 {
 621     struct test_iothread_data *data = opaque;
 622
 623     aio_context_acquire(bdrv_get_aio_context(data->bs));
 624     do_drain_begin(data->drain_type, data->bs);
 625     g_assert_cmpint(*data->aio_ret, ==, 0);
 626     do_drain_end(data->drain_type, data->bs);
 627     aio_context_release(bdrv_get_aio_context(data->bs));
 628
 629     qemu_event_set(&done_event);
 630 }
 631
 632 static void test_iothread_aio_cb(void *opaque, int ret)
 633 {
 634     int *aio_ret = opaque;
 635     *aio_ret = ret;
 636     qemu_event_set(&done_event);
 637 }
 638
 639 static void test_iothread_main_thread_bh(void *opaque)
 640 {
 641     struct test_iothread_data *data = opaque;
 642
 643     /* Test that the AioContext is not yet locked in a random BH that is
 644      * executed during drain, otherwise this would deadlock. */
 645     aio_context_acquire(bdrv_get_aio_context(data->bs));
 646     bdrv_flush(data->bs);
 647     aio_context_release(bdrv_get_aio_context(data->bs));
 648 }
 649
 650 /*
 651  * Starts an AIO request on a BDS that runs in the AioContext of iothread 1.
 652  * The request involves a BH on iothread 2 before it can complete.
 653  *
 654  * @drain_thread = 0 means that do_drain_begin/end are called from the main
 655  * thread, @drain_thread = 1 means that they are called from iothread 1. Drain
 656  * for this BDS cannot be called from iothread 2 because only the main thread
 657  * may do cross-AioContext polling.
 658  */
 659 static void test_iothread_common(enum drain_type drain_type, int drain_thread)
 660 {
 661     BlockBackend *blk;
 662     BlockDriverState *bs;
 663     BDRVTestState *s;
 664     BlockAIOCB *acb;
 665     int aio_ret;
 666     struct test_iothread_data data;
 667
 668     IOThread *a = iothread_new();
 669     IOThread *b = iothread_new();
 670     AioContext *ctx_a = iothread_get_aio_context(a);
 671     AioContext *ctx_b = iothread_get_aio_context(b);
 672
 673     QEMUIOVector qiov;
 674     struct iovec iov = {
 675         .iov_base = NULL,
 676         .iov_len = 0,
 677     };
 678     qemu_iovec_init_external(&qiov, &iov, 1);
 679
 680     /* bdrv_drain_all() may only be called from the main loop thread */
 681     if (drain_type == BDRV_DRAIN_ALL && drain_thread != 0) {
 682         goto out;
 683     }
 684
 685     blk = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
 686     bs = bdrv_new_open_driver(&bdrv_test, "test-node", BDRV_O_RDWR,
 687                               &error_abort);
 688     s = bs->opaque;
 689     blk_insert_bs(blk, bs, &error_abort);
 690
 691     blk_set_aio_context(blk, ctx_a);
 692     aio_context_acquire(ctx_a);
 693
 694     s->bh_indirection_ctx = ctx_b;
 695
 696     aio_ret = -EINPROGRESS;
 697     if (drain_thread == 0) {
 698         acb = blk_aio_preadv(blk, 0, &qiov, 0, test_iothread_aio_cb, &aio_ret);
 699     } else {
 700         acb = blk_aio_preadv(blk, 0, &qiov, 0, aio_ret_cb, &aio_ret);
 701     }
 702     g_assert(acb != NULL);
 703     g_assert_cmpint(aio_ret, ==, -EINPROGRESS);
 704
 705     aio_context_release(ctx_a);
 706
 707     data = (struct test_iothread_data) {
 708         .bs         = bs,
 709         .drain_type = drain_type,
 710         .aio_ret    = &aio_ret,
 711     };
 712
 713     switch (drain_thread) {
 714     case 0:
 715         if (drain_type != BDRV_DRAIN_ALL) {
 716             aio_context_acquire(ctx_a);
 717         }
 718
 719         aio_bh_schedule_oneshot(ctx_a, test_iothread_main_thread_bh, &data);
 720
 721         /* The request is running on the IOThread a. Draining its block device
 722          * will make sure that it has completed as far as the BDS is concerned,
 723          * but the drain in this thread can continue immediately after
 724          * bdrv_dec_in_flight() and aio_ret might be assigned only slightly
 725          * later. */
 726         qemu_event_reset(&done_event);
 727         do_drain_begin(drain_type, bs);
 728         g_assert_cmpint(bs->in_flight, ==, 0);
 729
 730         if (drain_type != BDRV_DRAIN_ALL) {
 731             aio_context_release(ctx_a);
 732         }
 733         qemu_event_wait(&done_event);
 734         if (drain_type != BDRV_DRAIN_ALL) {
 735             aio_context_acquire(ctx_a);
 736         }
 737
 738         g_assert_cmpint(aio_ret, ==, 0);
 739         do_drain_end(drain_type, bs);
 740
 741         if (drain_type != BDRV_DRAIN_ALL) {
 742             aio_context_release(ctx_a);
 743         }
 744         break;
 745     case 1:
 746         qemu_event_reset(&done_event);
 747         aio_bh_schedule_oneshot(ctx_a, test_iothread_drain_entry, &data);
 748         qemu_event_wait(&done_event);
 749         break;
 750     default:
 751         g_assert_not_reached();
 752     }
 753
 754     aio_context_acquire(ctx_a);
 755     blk_set_aio_context(blk, qemu_get_aio_context());
 756     aio_context_release(ctx_a);
 757
 758     bdrv_unref(bs);
 759     blk_unref(blk);
 760
 761 out:
 762     iothread_join(a);
 763     iothread_join(b);
 764 }
 765
 766 static void test_iothread_drain_all(void)
 767 {
 768     test_iothread_common(BDRV_DRAIN_ALL, 0);
 769     test_iothread_common(BDRV_DRAIN_ALL, 1);
 770 }
 771
 772 static void test_iothread_drain(void)
 773 {
 774     test_iothread_common(BDRV_DRAIN, 0);
 775     test_iothread_common(BDRV_DRAIN, 1);
 776 }
 777
 778 static void test_iothread_drain_subtree(void)
 779 {
 780     test_iothread_common(BDRV_SUBTREE_DRAIN, 0);
 781     test_iothread_common(BDRV_SUBTREE_DRAIN, 1);
 782 }
 783
 784
 785 typedef struct TestBlockJob {
 786     BlockJob common;
 787     int run_ret;
 788     int prepare_ret;
 789     bool should_complete;
 790 } TestBlockJob;
 791
 792 static int test_job_prepare(Job *job)
 793 {
 794     TestBlockJob *s = container_of(job, TestBlockJob, common.job);
 795
 796     /* Provoke an AIO_WAIT_WHILE() call to verify there is no deadlock */
 797     blk_flush(s->common.blk);
 798     return s->prepare_ret;
 799 }
 800
 801 static void test_job_commit(Job *job)
 802 {
 803     TestBlockJob *s = container_of(job, TestBlockJob, common.job);
 804
 805     /* Provoke an AIO_WAIT_WHILE() call to verify there is no deadlock */
 806     blk_flush(s->common.blk);
 807 }
 808
 809 static void test_job_abort(Job *job)
 810 {
 811     TestBlockJob *s = container_of(job, TestBlockJob, common.job);
 812
 813     /* Provoke an AIO_WAIT_WHILE() call to verify there is no deadlock */
 814     blk_flush(s->common.blk);
 815 }
 816
 817 static int coroutine_fn test_job_run(Job *job, Error **errp)
 818 {
 819     TestBlockJob *s = container_of(job, TestBlockJob, common.job);
 820
 821     job_transition_to_ready(&s->common.job);
 822     while (!s->should_complete) {
 823         /* Avoid job_sleep_ns() because it marks the job as !busy. We want to
 824          * emulate some actual activity (probably some I/O) here so that drain
 825          * has to wait for this activity to stop. */
 826         qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, 100000);
 827         job_pause_point(&s->common.job);
 828     }
 829
 830     return s->run_ret;
 831 }
 832
 833 static void test_job_complete(Job *job, Error **errp)
 834 {
 835     TestBlockJob *s = container_of(job, TestBlockJob, common.job);
 836     s->should_complete = true;
 837 }
 838
 839 BlockJobDriver test_job_driver = {
 840     .job_driver = {
 841         .instance_size  = sizeof(TestBlockJob),
 842         .free           = block_job_free,
 843         .user_resume    = block_job_user_resume,
 844         .drain          = block_job_drain,
 845         .run            = test_job_run,
 846         .complete       = test_job_complete,
 847         .prepare        = test_job_prepare,
 848         .commit         = test_job_commit,
 849         .abort          = test_job_abort,
 850     },
 851 };
 852
 853 enum test_job_result {
 854     TEST_JOB_SUCCESS,
 855     TEST_JOB_FAIL_RUN,
 856     TEST_JOB_FAIL_PREPARE,
 857 };
 858
 859 static void test_blockjob_common(enum drain_type drain_type, bool use_iothread,
 860                                  enum test_job_result result)
 861 {
 862     BlockBackend *blk_src, *blk_target;
 863     BlockDriverState *src, *target;
 864     BlockJob *job;
 865     TestBlockJob *tjob;
 866     IOThread *iothread = NULL;
 867     AioContext *ctx;
 868     int ret;
 869
 870     src = bdrv_new_open_driver(&bdrv_test, "source", BDRV_O_RDWR,
 871                                &error_abort);
 872     blk_src = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
 873     blk_insert_bs(blk_src, src, &error_abort);
 874
 875     if (use_iothread) {
 876         iothread = iothread_new();
 877         ctx = iothread_get_aio_context(iothread);
 878         blk_set_aio_context(blk_src, ctx);
 879     } else {
 880         ctx = qemu_get_aio_context();
 881     }
 882
 883     target = bdrv_new_open_driver(&bdrv_test, "target", BDRV_O_RDWR,
 884                                   &error_abort);
 885     blk_target = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
 886     blk_insert_bs(blk_target, target, &error_abort);
 887
 888     aio_context_acquire(ctx);
 889     tjob = block_job_create("job0", &test_job_driver, NULL, src,
 890                             0, BLK_PERM_ALL,
 891                             0, 0, NULL, NULL, &error_abort);
 892     job = &tjob->common;
 893     block_job_add_bdrv(job, "target", target, 0, BLK_PERM_ALL, &error_abort);
 894
 895     switch (result) {
 896     case TEST_JOB_SUCCESS:
 897         break;
 898     case TEST_JOB_FAIL_RUN:
 899         tjob->run_ret = -EIO;
 900         break;
 901     case TEST_JOB_FAIL_PREPARE:
 902         tjob->prepare_ret = -EIO;
 903         break;
 904     }
 905
 906     job_start(&job->job);
 907     aio_context_release(ctx);
 908
 909     g_assert_cmpint(job->job.pause_count, ==, 0);
 910     g_assert_false(job->job.paused);
 911     g_assert_true(job->job.busy); /* We're in qemu_co_sleep_ns() */
 912
 913     do_drain_begin_unlocked(drain_type, src);
 914
 915     if (drain_type == BDRV_DRAIN_ALL) {
 916         /* bdrv_drain_all() drains both src and target */
 917         g_assert_cmpint(job->job.pause_count, ==, 2);
 918     } else {
 919         g_assert_cmpint(job->job.pause_count, ==, 1);
 920     }
 921     g_assert_true(job->job.paused);
 922     g_assert_false(job->job.busy); /* The job is paused */
 923
 924     do_drain_end_unlocked(drain_type, src);
 925
 926     if (use_iothread) {
 927         /* paused is reset in the I/O thread, wait for it */
 928         while (job->job.paused) {
 929             aio_poll(qemu_get_aio_context(), false);
 930         }
 931     }
 932
 933     g_assert_cmpint(job->job.pause_count, ==, 0);
 934     g_assert_false(job->job.paused);
 935     g_assert_true(job->job.busy); /* We're in qemu_co_sleep_ns() */
 936
 937     do_drain_begin(drain_type, target);
 938
 939     if (drain_type == BDRV_DRAIN_ALL) {
 940         /* bdrv_drain_all() drains both src and target */
 941         g_assert_cmpint(job->job.pause_count, ==, 2);
 942     } else {
 943         g_assert_cmpint(job->job.pause_count, ==, 1);
 944     }
 945     g_assert_true(job->job.paused);
 946     g_assert_false(job->job.busy); /* The job is paused */
 947
 948     do_drain_end(drain_type, target);
 949
 950     if (use_iothread) {
 951         /* paused is reset in the I/O thread, wait for it */
 952         while (job->job.paused) {
 953             aio_poll(qemu_get_aio_context(), false);
 954         }
 955     }
 956
 957     g_assert_cmpint(job->job.pause_count, ==, 0);
 958     g_assert_false(job->job.paused);
 959     g_assert_true(job->job.busy); /* We're in qemu_co_sleep_ns() */
 960
 961     aio_context_acquire(ctx);
 962     ret = job_complete_sync(&job->job, &error_abort);
 963     g_assert_cmpint(ret, ==, (result == TEST_JOB_SUCCESS ? 0 : -EIO));
 964
 965     if (use_iothread) {
 966         blk_set_aio_context(blk_src, qemu_get_aio_context());
 967     }
 968     aio_context_release(ctx);
 969
 970     blk_unref(blk_src);
 971     blk_unref(blk_target);
 972     bdrv_unref(src);
 973     bdrv_unref(target);
 974
 975     if (iothread) {
 976         iothread_join(iothread);
 977     }
 978 }
 979
 980 static void test_blockjob_drain_all(void)
 981 {
 982     test_blockjob_common(BDRV_DRAIN_ALL, false, TEST_JOB_SUCCESS);
 983 }
 984
 985 static void test_blockjob_drain(void)
 986 {
 987     test_blockjob_common(BDRV_DRAIN, false, TEST_JOB_SUCCESS);
 988 }
 989
 990 static void test_blockjob_drain_subtree(void)
 991 {
 992     test_blockjob_common(BDRV_SUBTREE_DRAIN, false, TEST_JOB_SUCCESS);
 993 }
 994
 995 static void test_blockjob_error_drain_all(void)
 996 {
 997     test_blockjob_common(BDRV_DRAIN_ALL, false, TEST_JOB_FAIL_RUN);
 998     test_blockjob_common(BDRV_DRAIN_ALL, false, TEST_JOB_FAIL_PREPARE);
 999 }
1000
1001 static void test_blockjob_error_drain(void)
1002 {
1003     test_blockjob_common(BDRV_DRAIN, false, TEST_JOB_FAIL_RUN);
1004     test_blockjob_common(BDRV_DRAIN, false, TEST_JOB_FAIL_PREPARE);
1005 }
1006
1007 static void test_blockjob_error_drain_subtree(void)
1008 {
1009     test_blockjob_common(BDRV_SUBTREE_DRAIN, false, TEST_JOB_FAIL_RUN);
1010     test_blockjob_common(BDRV_SUBTREE_DRAIN, false, TEST_JOB_FAIL_PREPARE);
1011 }
1012
1013 static void test_blockjob_iothread_drain_all(void)
1014 {
1015     test_blockjob_common(BDRV_DRAIN_ALL, true, TEST_JOB_SUCCESS);
1016 }
1017
1018 static void test_blockjob_iothread_drain(void)
1019 {
1020     test_blockjob_common(BDRV_DRAIN, true, TEST_JOB_SUCCESS);
1021 }
1022
1023 static void test_blockjob_iothread_drain_subtree(void)
1024 {
1025     test_blockjob_common(BDRV_SUBTREE_DRAIN, true, TEST_JOB_SUCCESS);
1026 }
1027
1028 static void test_blockjob_iothread_error_drain_all(void)
1029 {
1030     test_blockjob_common(BDRV_DRAIN_ALL, true, TEST_JOB_FAIL_RUN);
1031     test_blockjob_common(BDRV_DRAIN_ALL, true, TEST_JOB_FAIL_PREPARE);
1032 }
1033
1034 static void test_blockjob_iothread_error_drain(void)
1035 {
1036     test_blockjob_common(BDRV_DRAIN, true, TEST_JOB_FAIL_RUN);
1037     test_blockjob_common(BDRV_DRAIN, true, TEST_JOB_FAIL_PREPARE);
1038 }
1039
1040 static void test_blockjob_iothread_error_drain_subtree(void)
1041 {
1042     test_blockjob_common(BDRV_SUBTREE_DRAIN, true, TEST_JOB_FAIL_RUN);
1043     test_blockjob_common(BDRV_SUBTREE_DRAIN, true, TEST_JOB_FAIL_PREPARE);
1044 }
1045
1046
1047 typedef struct BDRVTestTopState {
1048     BdrvChild *wait_child;
1049 } BDRVTestTopState;
1050
1051 static void bdrv_test_top_close(BlockDriverState *bs)
1052 {
1053     BdrvChild *c, *next_c;
1054     QLIST_FOREACH_SAFE(c, &bs->children, next, next_c) {
1055         bdrv_unref_child(bs, c);
1056     }
1057 }
1058
1059 static int coroutine_fn bdrv_test_top_co_preadv(BlockDriverState *bs,
1060                                                 uint64_t offset, uint64_t bytes,
1061                                                 QEMUIOVector *qiov, int flags)
1062 {
1063     BDRVTestTopState *tts = bs->opaque;
1064     return bdrv_co_preadv(tts->wait_child, offset, bytes, qiov, flags);
1065 }
1066
1067 static BlockDriver bdrv_test_top_driver = {
1068     .format_name            = "test_top_driver",
1069     .instance_size          = sizeof(BDRVTestTopState),
1070
1071     .bdrv_close             = bdrv_test_top_close,
1072     .bdrv_co_preadv         = bdrv_test_top_co_preadv,
1073
1074     .bdrv_child_perm        = bdrv_format_default_perms,
1075 };
1076
1077 typedef struct TestCoDeleteByDrainData {
1078     BlockBackend *blk;
1079     bool detach_instead_of_delete;
1080     bool done;
1081 } TestCoDeleteByDrainData;
1082
1083 static void coroutine_fn test_co_delete_by_drain(void *opaque)
1084 {
1085     TestCoDeleteByDrainData *dbdd = opaque;
1086     BlockBackend *blk = dbdd->blk;
1087     BlockDriverState *bs = blk_bs(blk);
1088     BDRVTestTopState *tts = bs->opaque;
1089     void *buffer = g_malloc(65536);
1090     QEMUIOVector qiov;
1091     struct iovec iov = {
1092         .iov_base = buffer,
1093         .iov_len  = 65536,
1094     };
1095
1096     qemu_iovec_init_external(&qiov, &iov, 1);
1097
1098     /* Pretend some internal write operation from parent to child.
1099      * Important: We have to read from the child, not from the parent!
1100      * Draining works by first propagating it all up the tree to the
1101      * root and then waiting for drainage from root to the leaves
1102      * (protocol nodes).  If we have a request waiting on the root,
1103      * everything will be drained before we go back down the tree, but
1104      * we do not want that.  We want to be in the middle of draining
1105      * when this following requests returns. */
1106     bdrv_co_preadv(tts->wait_child, 0, 65536, &qiov, 0);
1107
1108     g_assert_cmpint(bs->refcnt, ==, 1);
1109
1110     if (!dbdd->detach_instead_of_delete) {
1111         blk_unref(blk);
1112     } else {
1113         BdrvChild *c, *next_c;
1114         QLIST_FOREACH_SAFE(c, &bs->children, next, next_c) {
1115             bdrv_unref_child(bs, c);
1116         }
1117     }
1118
1119     dbdd->done = true;
1120     g_free(buffer);
1121 }
1122
1123 /**
1124  * Test what happens when some BDS has some children, you drain one of
1125  * them and this results in the BDS being deleted.
1126  *
1127  * If @detach_instead_of_delete is set, the BDS is not going to be
1128  * deleted but will only detach all of its children.
1129  */
1130 static void do_test_delete_by_drain(bool detach_instead_of_delete,
1131                                     enum drain_type drain_type)
1132 {
1133     BlockBackend *blk;
1134     BlockDriverState *bs, *child_bs, *null_bs;
1135     BDRVTestTopState *tts;
1136     TestCoDeleteByDrainData dbdd;
1137     Coroutine *co;
1138
1139     bs = bdrv_new_open_driver(&bdrv_test_top_driver, "top", BDRV_O_RDWR,
1140                               &error_abort);
1141     bs->total_sectors = 65536 >> BDRV_SECTOR_BITS;
1142     tts = bs->opaque;
1143
1144     null_bs = bdrv_open("null-co://", NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL,
1145                         &error_abort);
1146     bdrv_attach_child(bs, null_bs, "null-child", &child_file, &error_abort);
1147
1148     /* This child will be the one to pass to requests through to, and
1149      * it will stall until a drain occurs */
1150     child_bs = bdrv_new_open_driver(&bdrv_test, "child", BDRV_O_RDWR,
1151                                     &error_abort);
1152     child_bs->total_sectors = 65536 >> BDRV_SECTOR_BITS;
1153     /* Takes our reference to child_bs */
1154     tts->wait_child = bdrv_attach_child(bs, child_bs, "wait-child", &child_file,
1155                                         &error_abort);
1156
1157     /* This child is just there to be deleted
1158      * (for detach_instead_of_delete == true) */
1159     null_bs = bdrv_open("null-co://", NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL,
1160                         &error_abort);
1161     bdrv_attach_child(bs, null_bs, "null-child", &child_file, &error_abort);
1162
1163     blk = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
1164     blk_insert_bs(blk, bs, &error_abort);
1165
1166     /* Referenced by blk now */
1167     bdrv_unref(bs);
1168
1169     g_assert_cmpint(bs->refcnt, ==, 1);
1170     g_assert_cmpint(child_bs->refcnt, ==, 1);
1171     g_assert_cmpint(null_bs->refcnt, ==, 1);
1172
1173
1174     dbdd = (TestCoDeleteByDrainData){
1175         .blk = blk,
1176         .detach_instead_of_delete = detach_instead_of_delete,
1177         .done = false,
1178     };
1179     co = qemu_coroutine_create(test_co_delete_by_drain, &dbdd);
1180     qemu_coroutine_enter(co);
1181
1182     /* Drain the child while the read operation is still pending.
1183      * This should result in the operation finishing and
1184      * test_co_delete_by_drain() resuming.  Thus, @bs will be deleted
1185      * and the coroutine will exit while this drain operation is still
1186      * in progress. */
1187     switch (drain_type) {
1188     case BDRV_DRAIN:
1189         bdrv_ref(child_bs);
1190         bdrv_drain(child_bs);
1191         bdrv_unref(child_bs);
1192         break;
1193     case BDRV_SUBTREE_DRAIN:
1194         /* Would have to ref/unref bs here for !detach_instead_of_delete, but
1195          * then the whole test becomes pointless because the graph changes
1196          * don't occur during the drain any more. */
1197         assert(detach_instead_of_delete);
1198         bdrv_subtree_drained_begin(bs);
1199         bdrv_subtree_drained_end(bs);
1200         break;
1201     case BDRV_DRAIN_ALL:
1202         bdrv_drain_all_begin();
1203         bdrv_drain_all_end();
1204         break;
1205     default:
1206         g_assert_not_reached();
1207     }
1208
1209     while (!dbdd.done) {
1210         aio_poll(qemu_get_aio_context(), true);
1211     }
1212
1213     if (detach_instead_of_delete) {
1214         /* Here, the reference has not passed over to the coroutine,
1215          * so we have to delete the BB ourselves */
1216         blk_unref(blk);
1217     }
1218 }
1219
1220 static void test_delete_by_drain(void)
1221 {
1222     do_test_delete_by_drain(false, BDRV_DRAIN);
1223 }
1224
1225 static void test_detach_by_drain_all(void)
1226 {
1227     do_test_delete_by_drain(true, BDRV_DRAIN_ALL);
1228 }
1229
1230 static void test_detach_by_drain(void)
1231 {
1232     do_test_delete_by_drain(true, BDRV_DRAIN);
1233 }
1234
1235 static void test_detach_by_drain_subtree(void)
1236 {
1237     do_test_delete_by_drain(true, BDRV_SUBTREE_DRAIN);
1238 }
1239
1240
1241 struct detach_by_parent_data {
1242     BlockDriverState *parent_b;
1243     BdrvChild *child_b;
1244     BlockDriverState *c;
1245     BdrvChild *child_c;
1246     bool by_parent_cb;
1247 };
1248 static struct detach_by_parent_data detach_by_parent_data;
1249
1250 static void detach_indirect_bh(void *opaque)
1251 {
1252     struct detach_by_parent_data *data = opaque;
1253
1254     bdrv_unref_child(data->parent_b, data->child_b);
1255
1256     bdrv_ref(data->c);
1257     data->child_c = bdrv_attach_child(data->parent_b, data->c, "PB-C",
1258                                       &child_file, &error_abort);
1259 }
1260
1261 static void detach_by_parent_aio_cb(void *opaque, int ret)
1262 {
1263     struct detach_by_parent_data *data = &detach_by_parent_data;
1264
1265     g_assert_cmpint(ret, ==, 0);
1266     if (data->by_parent_cb) {
1267         detach_indirect_bh(data);
1268     }
1269 }
1270
1271 static void detach_by_driver_cb_drained_begin(BdrvChild *child)
1272 {
1273     aio_bh_schedule_oneshot(qemu_get_current_aio_context(),
1274                             detach_indirect_bh, &detach_by_parent_data);
1275     child_file.drained_begin(child);
1276 }
1277
1278 static BdrvChildRole detach_by_driver_cb_role;
1279
1280 /*
1281  * Initial graph:
1282  *
1283  * PA     PB
1284  *    \ /   \
1285  *     A     B     C
1286  *
1287  * by_parent_cb == true:  Test that parent callbacks don't poll
1288  *
1289  *     PA has a pending write request whose callback changes the child nodes of
1290  *     PB: It removes B and adds C instead. The subtree of PB is drained, which
1291  *     will indirectly drain the write request, too.
1292  *
1293  * by_parent_cb == false: Test that bdrv_drain_invoke() doesn't poll
1294  *
1295  *     PA's BdrvChildRole has a .drained_begin callback that schedules a BH
1296  *     that does the same graph change. If bdrv_drain_invoke() calls it, the
1297  *     state is messed up, but if it is only polled in the single
1298  *     BDRV_POLL_WHILE() at the end of the drain, this should work fine.
1299  */
1300 static void test_detach_indirect(bool by_parent_cb)
1301 {
1302     BlockBackend *blk;
1303     BlockDriverState *parent_a, *parent_b, *a, *b, *c;
1304     BdrvChild *child_a, *child_b;
1305     BlockAIOCB *acb;
1306
1307     QEMUIOVector qiov;
1308     struct iovec iov = {
1309         .iov_base = NULL,
1310         .iov_len = 0,
1311     };
1312     qemu_iovec_init_external(&qiov, &iov, 1);
1313
1314     if (!by_parent_cb) {
1315         detach_by_driver_cb_role = child_file;
1316         detach_by_driver_cb_role.drained_begin =
1317             detach_by_driver_cb_drained_begin;
1318     }
1319
1320     /* Create all involved nodes */
1321     parent_a = bdrv_new_open_driver(&bdrv_test, "parent-a", BDRV_O_RDWR,
1322                                     &error_abort);
1323     parent_b = bdrv_new_open_driver(&bdrv_test, "parent-b", 0,
1324                                     &error_abort);
1325
1326     a = bdrv_new_open_driver(&bdrv_test, "a", BDRV_O_RDWR, &error_abort);
1327     b = bdrv_new_open_driver(&bdrv_test, "b", BDRV_O_RDWR, &error_abort);
1328     c = bdrv_new_open_driver(&bdrv_test, "c", BDRV_O_RDWR, &error_abort);
1329
1330     /* blk is a BB for parent-a */
1331     blk = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
1332     blk_insert_bs(blk, parent_a, &error_abort);
1333     bdrv_unref(parent_a);
1334
1335     /* If we want to get bdrv_drain_invoke() to call aio_poll(), the driver
1336      * callback must not return immediately. */
1337     if (!by_parent_cb) {
1338         BDRVTestState *s = parent_a->opaque;
1339         s->sleep_in_drain_begin = true;
1340     }
1341
1342     /* Set child relationships */
1343     bdrv_ref(b);
1344     bdrv_ref(a);
1345     child_b = bdrv_attach_child(parent_b, b, "PB-B", &child_file, &error_abort);
1346     child_a = bdrv_attach_child(parent_b, a, "PB-A", &child_backing, &error_abort);
1347
1348     bdrv_ref(a);
1349     bdrv_attach_child(parent_a, a, "PA-A",
1350                       by_parent_cb ? &child_file : &detach_by_driver_cb_role,
1351                       &error_abort);
1352
1353     g_assert_cmpint(parent_a->refcnt, ==, 1);
1354     g_assert_cmpint(parent_b->refcnt, ==, 1);
1355     g_assert_cmpint(a->refcnt, ==, 3);
1356     g_assert_cmpint(b->refcnt, ==, 2);
1357     g_assert_cmpint(c->refcnt, ==, 1);
1358
1359     g_assert(QLIST_FIRST(&parent_b->children) == child_a);
1360     g_assert(QLIST_NEXT(child_a, next) == child_b);
1361     g_assert(QLIST_NEXT(child_b, next) == NULL);
1362
1363     /* Start the evil write request */
1364     detach_by_parent_data = (struct detach_by_parent_data) {
1365         .parent_b = parent_b,
1366         .child_b = child_b,
1367         .c = c,
1368         .by_parent_cb = by_parent_cb,
1369     };
1370     acb = blk_aio_preadv(blk, 0, &qiov, 0, detach_by_parent_aio_cb, NULL);
1371     g_assert(acb != NULL);
1372
1373     /* Drain and check the expected result */
1374     bdrv_subtree_drained_begin(parent_b);
1375
1376     g_assert(detach_by_parent_data.child_c != NULL);
1377
1378     g_assert_cmpint(parent_a->refcnt, ==, 1);
1379     g_assert_cmpint(parent_b->refcnt, ==, 1);
1380     g_assert_cmpint(a->refcnt, ==, 3);
1381     g_assert_cmpint(b->refcnt, ==, 1);
1382     g_assert_cmpint(c->refcnt, ==, 2);
1383
1384     g_assert(QLIST_FIRST(&parent_b->children) == detach_by_parent_data.child_c);
1385     g_assert(QLIST_NEXT(detach_by_parent_data.child_c, next) == child_a);
1386     g_assert(QLIST_NEXT(child_a, next) == NULL);
1387
1388     g_assert_cmpint(parent_a->quiesce_counter, ==, 1);
1389     g_assert_cmpint(parent_b->quiesce_counter, ==, 1);
1390     g_assert_cmpint(a->quiesce_counter, ==, 1);
1391     g_assert_cmpint(b->quiesce_counter, ==, 0);
1392     g_assert_cmpint(c->quiesce_counter, ==, 1);
1393
1394     bdrv_subtree_drained_end(parent_b);
1395
1396     bdrv_unref(parent_b);
1397     blk_unref(blk);
1398
1399     /* XXX Once bdrv_close() unref's children instead of just detaching them,
1400      * this won't be necessary any more. */
1401     bdrv_unref(a);
1402     bdrv_unref(a);
1403     bdrv_unref(c);
1404
1405     g_assert_cmpint(a->refcnt, ==, 1);
1406     g_assert_cmpint(b->refcnt, ==, 1);
1407     g_assert_cmpint(c->refcnt, ==, 1);
1408     bdrv_unref(a);
1409     bdrv_unref(b);
1410     bdrv_unref(c);
1411 }
1412
1413 static void test_detach_by_parent_cb(void)
1414 {
1415     test_detach_indirect(true);
1416 }
1417
1418 static void test_detach_by_driver_cb(void)
1419 {
1420     test_detach_indirect(false);
1421 }
1422
1423 static void test_append_to_drained(void)
1424 {
1425     BlockBackend *blk;
1426     BlockDriverState *base, *overlay;
1427     BDRVTestState *base_s, *overlay_s;
1428
1429     blk = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
1430     base = bdrv_new_open_driver(&bdrv_test, "base", BDRV_O_RDWR, &error_abort);
1431     base_s = base->opaque;
1432     blk_insert_bs(blk, base, &error_abort);
1433
1434     overlay = bdrv_new_open_driver(&bdrv_test, "overlay", BDRV_O_RDWR,
1435                                    &error_abort);
1436     overlay_s = overlay->opaque;
1437
1438     do_drain_begin(BDRV_DRAIN, base);
1439     g_assert_cmpint(base->quiesce_counter, ==, 1);
1440     g_assert_cmpint(base_s->drain_count, ==, 1);
1441     g_assert_cmpint(base->in_flight, ==, 0);
1442
1443     /* Takes ownership of overlay, so we don't have to unref it later */
1444     bdrv_append(overlay, base, &error_abort);
1445     g_assert_cmpint(base->in_flight, ==, 0);
1446     g_assert_cmpint(overlay->in_flight, ==, 0);
1447
1448     g_assert_cmpint(base->quiesce_counter, ==, 1);
1449     g_assert_cmpint(base_s->drain_count, ==, 1);
1450     g_assert_cmpint(overlay->quiesce_counter, ==, 1);
1451     g_assert_cmpint(overlay_s->drain_count, ==, 1);
1452
1453     do_drain_end(BDRV_DRAIN, base);
1454
1455     g_assert_cmpint(base->quiesce_counter, ==, 0);
1456     g_assert_cmpint(base_s->drain_count, ==, 0);
1457     g_assert_cmpint(overlay->quiesce_counter, ==, 0);
1458     g_assert_cmpint(overlay_s->drain_count, ==, 0);
1459
1460     bdrv_unref(base);
1461     blk_unref(blk);
1462 }
1463
1464 int main(int argc, char **argv)
1465 {
1466     int ret;
1467
1468     bdrv_init();
1469     qemu_init_main_loop(&error_abort);
1470
1471     g_test_init(&argc, &argv, NULL);
1472     qemu_event_init(&done_event, false);
1473
1474     g_test_add_func("/bdrv-drain/driver-cb/drain_all", test_drv_cb_drain_all);
1475     g_test_add_func("/bdrv-drain/driver-cb/drain", test_drv_cb_drain);
1476     g_test_add_func("/bdrv-drain/driver-cb/drain_subtree",
1477                     test_drv_cb_drain_subtree);
1478
1479     g_test_add_func("/bdrv-drain/driver-cb/co/drain_all",
1480                     test_drv_cb_co_drain_all);
1481     g_test_add_func("/bdrv-drain/driver-cb/co/drain", test_drv_cb_co_drain);
1482     g_test_add_func("/bdrv-drain/driver-cb/co/drain_subtree",
1483                     test_drv_cb_co_drain_subtree);
1484
1485
1486     g_test_add_func("/bdrv-drain/quiesce/drain_all", test_quiesce_drain_all);
1487     g_test_add_func("/bdrv-drain/quiesce/drain", test_quiesce_drain);
1488     g_test_add_func("/bdrv-drain/quiesce/drain_subtree",
1489                     test_quiesce_drain_subtree);
1490
1491     g_test_add_func("/bdrv-drain/quiesce/co/drain_all",
1492                     test_quiesce_co_drain_all);
1493     g_test_add_func("/bdrv-drain/quiesce/co/drain", test_quiesce_co_drain);
1494     g_test_add_func("/bdrv-drain/quiesce/co/drain_subtree",
1495                     test_quiesce_co_drain_subtree);
1496
1497     g_test_add_func("/bdrv-drain/nested", test_nested);
1498     g_test_add_func("/bdrv-drain/multiparent", test_multiparent);
1499
1500     g_test_add_func("/bdrv-drain/graph-change/drain_subtree",
1501                     test_graph_change_drain_subtree);
1502     g_test_add_func("/bdrv-drain/graph-change/drain_all",
1503                     test_graph_change_drain_all);
1504
1505     g_test_add_func("/bdrv-drain/iothread/drain_all", test_iothread_drain_all);
1506     g_test_add_func("/bdrv-drain/iothread/drain", test_iothread_drain);
1507     g_test_add_func("/bdrv-drain/iothread/drain_subtree",
1508                     test_iothread_drain_subtree);
1509
1510     g_test_add_func("/bdrv-drain/blockjob/drain_all", test_blockjob_drain_all);
1511     g_test_add_func("/bdrv-drain/blockjob/drain", test_blockjob_drain);
1512     g_test_add_func("/bdrv-drain/blockjob/drain_subtree",
1513                     test_blockjob_drain_subtree);
1514
1515     g_test_add_func("/bdrv-drain/blockjob/error/drain_all",
1516                     test_blockjob_error_drain_all);
1517     g_test_add_func("/bdrv-drain/blockjob/error/drain",
1518                     test_blockjob_error_drain);
1519     g_test_add_func("/bdrv-drain/blockjob/error/drain_subtree",
1520                     test_blockjob_error_drain_subtree);
1521
1522     g_test_add_func("/bdrv-drain/blockjob/iothread/drain_all",
1523                     test_blockjob_iothread_drain_all);
1524     g_test_add_func("/bdrv-drain/blockjob/iothread/drain",
1525                     test_blockjob_iothread_drain);
1526     g_test_add_func("/bdrv-drain/blockjob/iothread/drain_subtree",
1527                     test_blockjob_iothread_drain_subtree);
1528
1529     g_test_add_func("/bdrv-drain/blockjob/iothread/error/drain_all",
1530                     test_blockjob_iothread_error_drain_all);
1531     g_test_add_func("/bdrv-drain/blockjob/iothread/error/drain",
1532                     test_blockjob_iothread_error_drain);
1533     g_test_add_func("/bdrv-drain/blockjob/iothread/error/drain_subtree",
1534                     test_blockjob_iothread_error_drain_subtree);
1535
1536     g_test_add_func("/bdrv-drain/deletion/drain", test_delete_by_drain);
1537     g_test_add_func("/bdrv-drain/detach/drain_all", test_detach_by_drain_all);
1538     g_test_add_func("/bdrv-drain/detach/drain", test_detach_by_drain);
1539     g_test_add_func("/bdrv-drain/detach/drain_subtree", test_detach_by_drain_subtree);
1540     g_test_add_func("/bdrv-drain/detach/parent_cb", test_detach_by_parent_cb);
1541     g_test_add_func("/bdrv-drain/detach/driver_cb", test_detach_by_driver_cb);
1542
1543     g_test_add_func("/bdrv-drain/attach/drain", test_append_to_drained);
1544
1545     ret = g_test_run();
1546     qemu_event_destroy(&done_event);
1547     return ret;
1548 }