tests/test-bdrv-drain.c

   1 /*
   2  * Block node draining tests
   3  *
   4  * Copyright (c) 2017 Kevin Wolf <kwolf@redhat.com>
   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     qemu_event_reset(&done_event);
 698
 699     if (drain_thread == 0) {
 700         acb = blk_aio_preadv(blk, 0, &qiov, 0, test_iothread_aio_cb, &aio_ret);
 701     } else {
 702         acb = blk_aio_preadv(blk, 0, &qiov, 0, aio_ret_cb, &aio_ret);
 703     }
 704     g_assert(acb != NULL);
 705     g_assert_cmpint(aio_ret, ==, -EINPROGRESS);
 706
 707     aio_context_release(ctx_a);
 708
 709     data = (struct test_iothread_data) {
 710         .bs         = bs,
 711         .drain_type = drain_type,
 712         .aio_ret    = &aio_ret,
 713     };
 714
 715     switch (drain_thread) {
 716     case 0:
 717         if (drain_type != BDRV_DRAIN_ALL) {
 718             aio_context_acquire(ctx_a);
 719         }
 720
 721         aio_bh_schedule_oneshot(ctx_a, test_iothread_main_thread_bh, &data);
 722
 723         /* The request is running on the IOThread a. Draining its block device
 724          * will make sure that it has completed as far as the BDS is concerned,
 725          * but the drain in this thread can continue immediately after
 726          * bdrv_dec_in_flight() and aio_ret might be assigned only slightly
 727          * later. */
 728         do_drain_begin(drain_type, bs);
 729         g_assert_cmpint(bs->in_flight, ==, 0);
 730
 731         if (drain_type != BDRV_DRAIN_ALL) {
 732             aio_context_release(ctx_a);
 733         }
 734         qemu_event_wait(&done_event);
 735         if (drain_type != BDRV_DRAIN_ALL) {
 736             aio_context_acquire(ctx_a);
 737         }
 738
 739         g_assert_cmpint(aio_ret, ==, 0);
 740         do_drain_end(drain_type, bs);
 741
 742         if (drain_type != BDRV_DRAIN_ALL) {
 743             aio_context_release(ctx_a);
 744         }
 745         break;
 746     case 1:
 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 running;
 790     bool should_complete;
 791 } TestBlockJob;
 792
 793 static int test_job_prepare(Job *job)
 794 {
 795     TestBlockJob *s = container_of(job, TestBlockJob, common.job);
 796
 797     /* Provoke an AIO_WAIT_WHILE() call to verify there is no deadlock */
 798     blk_flush(s->common.blk);
 799     return s->prepare_ret;
 800 }
 801
 802 static void test_job_commit(Job *job)
 803 {
 804     TestBlockJob *s = container_of(job, TestBlockJob, common.job);
 805
 806     /* Provoke an AIO_WAIT_WHILE() call to verify there is no deadlock */
 807     blk_flush(s->common.blk);
 808 }
 809
 810 static void test_job_abort(Job *job)
 811 {
 812     TestBlockJob *s = container_of(job, TestBlockJob, common.job);
 813
 814     /* Provoke an AIO_WAIT_WHILE() call to verify there is no deadlock */
 815     blk_flush(s->common.blk);
 816 }
 817
 818 static int coroutine_fn test_job_run(Job *job, Error **errp)
 819 {
 820     TestBlockJob *s = container_of(job, TestBlockJob, common.job);
 821
 822     /* We are running the actual job code past the pause point in
 823      * job_co_entry(). */
 824     s->running = true;
 825
 826     job_transition_to_ready(&s->common.job);
 827     while (!s->should_complete) {
 828         /* Avoid job_sleep_ns() because it marks the job as !busy. We want to
 829          * emulate some actual activity (probably some I/O) here so that drain
 830          * has to wait for this activity to stop. */
 831         qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, 1000000);
 832
 833         job_pause_point(&s->common.job);
 834     }
 835
 836     return s->run_ret;
 837 }
 838
 839 static void test_job_complete(Job *job, Error **errp)
 840 {
 841     TestBlockJob *s = container_of(job, TestBlockJob, common.job);
 842     s->should_complete = true;
 843 }
 844
 845 BlockJobDriver test_job_driver = {
 846     .job_driver = {
 847         .instance_size  = sizeof(TestBlockJob),
 848         .free           = block_job_free,
 849         .user_resume    = block_job_user_resume,
 850         .drain          = block_job_drain,
 851         .run            = test_job_run,
 852         .complete       = test_job_complete,
 853         .prepare        = test_job_prepare,
 854         .commit         = test_job_commit,
 855         .abort          = test_job_abort,
 856     },
 857 };
 858
 859 enum test_job_result {
 860     TEST_JOB_SUCCESS,
 861     TEST_JOB_FAIL_RUN,
 862     TEST_JOB_FAIL_PREPARE,
 863 };
 864
 865 enum test_job_drain_node {
 866     TEST_JOB_DRAIN_SRC,
 867     TEST_JOB_DRAIN_SRC_CHILD,
 868     TEST_JOB_DRAIN_SRC_PARENT,
 869 };
 870
 871 static void test_blockjob_common_drain_node(enum drain_type drain_type,
 872                                             bool use_iothread,
 873                                             enum test_job_result result,
 874                                             enum test_job_drain_node drain_node)
 875 {
 876     BlockBackend *blk_src, *blk_target;
 877     BlockDriverState *src, *src_backing, *src_overlay, *target, *drain_bs;
 878     BlockJob *job;
 879     TestBlockJob *tjob;
 880     IOThread *iothread = NULL;
 881     AioContext *ctx;
 882     int ret;
 883
 884     src = bdrv_new_open_driver(&bdrv_test, "source", BDRV_O_RDWR,
 885                                &error_abort);
 886     src_backing = bdrv_new_open_driver(&bdrv_test, "source-backing",
 887                                        BDRV_O_RDWR, &error_abort);
 888     src_overlay = bdrv_new_open_driver(&bdrv_test, "source-overlay",
 889                                        BDRV_O_RDWR, &error_abort);
 890
 891     bdrv_set_backing_hd(src_overlay, src, &error_abort);
 892     bdrv_unref(src);
 893     bdrv_set_backing_hd(src, src_backing, &error_abort);
 894     bdrv_unref(src_backing);
 895
 896     blk_src = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
 897     blk_insert_bs(blk_src, src_overlay, &error_abort);
 898
 899     switch (drain_node) {
 900     case TEST_JOB_DRAIN_SRC:
 901         drain_bs = src;
 902         break;
 903     case TEST_JOB_DRAIN_SRC_CHILD:
 904         drain_bs = src_backing;
 905         break;
 906     case TEST_JOB_DRAIN_SRC_PARENT:
 907         drain_bs = src_overlay;
 908         break;
 909     default:
 910         g_assert_not_reached();
 911     }
 912
 913     if (use_iothread) {
 914         iothread = iothread_new();
 915         ctx = iothread_get_aio_context(iothread);
 916         blk_set_aio_context(blk_src, ctx);
 917     } else {
 918         ctx = qemu_get_aio_context();
 919     }
 920
 921     target = bdrv_new_open_driver(&bdrv_test, "target", BDRV_O_RDWR,
 922                                   &error_abort);
 923     blk_target = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
 924     blk_insert_bs(blk_target, target, &error_abort);
 925
 926     aio_context_acquire(ctx);
 927     tjob = block_job_create("job0", &test_job_driver, NULL, src,
 928                             0, BLK_PERM_ALL,
 929                             0, 0, NULL, NULL, &error_abort);
 930     job = &tjob->common;
 931     block_job_add_bdrv(job, "target", target, 0, BLK_PERM_ALL, &error_abort);
 932
 933     switch (result) {
 934     case TEST_JOB_SUCCESS:
 935         break;
 936     case TEST_JOB_FAIL_RUN:
 937         tjob->run_ret = -EIO;
 938         break;
 939     case TEST_JOB_FAIL_PREPARE:
 940         tjob->prepare_ret = -EIO;
 941         break;
 942     }
 943
 944     job_start(&job->job);
 945     aio_context_release(ctx);
 946
 947     if (use_iothread) {
 948         /* job_co_entry() is run in the I/O thread, wait for the actual job
 949          * code to start (we don't want to catch the job in the pause point in
 950          * job_co_entry(). */
 951         while (!tjob->running) {
 952             aio_poll(qemu_get_aio_context(), false);
 953         }
 954     }
 955
 956     g_assert_cmpint(job->job.pause_count, ==, 0);
 957     g_assert_false(job->job.paused);
 958     g_assert_true(tjob->running);
 959     g_assert_true(job->job.busy); /* We're in qemu_co_sleep_ns() */
 960
 961     do_drain_begin_unlocked(drain_type, drain_bs);
 962
 963     if (drain_type == BDRV_DRAIN_ALL) {
 964         /* bdrv_drain_all() drains both src and target */
 965         g_assert_cmpint(job->job.pause_count, ==, 2);
 966     } else {
 967         g_assert_cmpint(job->job.pause_count, ==, 1);
 968     }
 969     g_assert_true(job->job.paused);
 970     g_assert_false(job->job.busy); /* The job is paused */
 971
 972     do_drain_end_unlocked(drain_type, drain_bs);
 973
 974     if (use_iothread) {
 975         /* paused is reset in the I/O thread, wait for it */
 976         while (job->job.paused) {
 977             aio_poll(qemu_get_aio_context(), false);
 978         }
 979     }
 980
 981     g_assert_cmpint(job->job.pause_count, ==, 0);
 982     g_assert_false(job->job.paused);
 983     g_assert_true(job->job.busy); /* We're in qemu_co_sleep_ns() */
 984
 985     do_drain_begin(drain_type, target);
 986
 987     if (drain_type == BDRV_DRAIN_ALL) {
 988         /* bdrv_drain_all() drains both src and target */
 989         g_assert_cmpint(job->job.pause_count, ==, 2);
 990     } else {
 991         g_assert_cmpint(job->job.pause_count, ==, 1);
 992     }
 993     g_assert_true(job->job.paused);
 994     g_assert_false(job->job.busy); /* The job is paused */
 995
 996     do_drain_end(drain_type, target);
 997
 998     if (use_iothread) {
 999         /* paused is reset in the I/O thread, wait for it */
1000         while (job->job.paused) {
1001             aio_poll(qemu_get_aio_context(), false);
1002         }
1003     }
1004
1005     g_assert_cmpint(job->job.pause_count, ==, 0);
1006     g_assert_false(job->job.paused);
1007     g_assert_true(job->job.busy); /* We're in qemu_co_sleep_ns() */
1008
1009     aio_context_acquire(ctx);
1010     ret = job_complete_sync(&job->job, &error_abort);
1011     g_assert_cmpint(ret, ==, (result == TEST_JOB_SUCCESS ? 0 : -EIO));
1012
1013     if (use_iothread) {
1014         blk_set_aio_context(blk_src, qemu_get_aio_context());
1015     }
1016     aio_context_release(ctx);
1017
1018     blk_unref(blk_src);
1019     blk_unref(blk_target);
1020     bdrv_unref(src_overlay);
1021     bdrv_unref(target);
1022
1023     if (iothread) {
1024         iothread_join(iothread);
1025     }
1026 }
1027
1028 static void test_blockjob_common(enum drain_type drain_type, bool use_iothread,
1029                                  enum test_job_result result)
1030 {
1031     test_blockjob_common_drain_node(drain_type, use_iothread, result,
1032                                     TEST_JOB_DRAIN_SRC);
1033     test_blockjob_common_drain_node(drain_type, use_iothread, result,
1034                                     TEST_JOB_DRAIN_SRC_CHILD);
1035     if (drain_type == BDRV_SUBTREE_DRAIN) {
1036         test_blockjob_common_drain_node(drain_type, use_iothread, result,
1037                                         TEST_JOB_DRAIN_SRC_PARENT);
1038     }
1039 }
1040
1041 static void test_blockjob_drain_all(void)
1042 {
1043     test_blockjob_common(BDRV_DRAIN_ALL, false, TEST_JOB_SUCCESS);
1044 }
1045
1046 static void test_blockjob_drain(void)
1047 {
1048     test_blockjob_common(BDRV_DRAIN, false, TEST_JOB_SUCCESS);
1049 }
1050
1051 static void test_blockjob_drain_subtree(void)
1052 {
1053     test_blockjob_common(BDRV_SUBTREE_DRAIN, false, TEST_JOB_SUCCESS);
1054 }
1055
1056 static void test_blockjob_error_drain_all(void)
1057 {
1058     test_blockjob_common(BDRV_DRAIN_ALL, false, TEST_JOB_FAIL_RUN);
1059     test_blockjob_common(BDRV_DRAIN_ALL, false, TEST_JOB_FAIL_PREPARE);
1060 }
1061
1062 static void test_blockjob_error_drain(void)
1063 {
1064     test_blockjob_common(BDRV_DRAIN, false, TEST_JOB_FAIL_RUN);
1065     test_blockjob_common(BDRV_DRAIN, false, TEST_JOB_FAIL_PREPARE);
1066 }
1067
1068 static void test_blockjob_error_drain_subtree(void)
1069 {
1070     test_blockjob_common(BDRV_SUBTREE_DRAIN, false, TEST_JOB_FAIL_RUN);
1071     test_blockjob_common(BDRV_SUBTREE_DRAIN, false, TEST_JOB_FAIL_PREPARE);
1072 }
1073
1074 static void test_blockjob_iothread_drain_all(void)
1075 {
1076     test_blockjob_common(BDRV_DRAIN_ALL, true, TEST_JOB_SUCCESS);
1077 }
1078
1079 static void test_blockjob_iothread_drain(void)
1080 {
1081     test_blockjob_common(BDRV_DRAIN, true, TEST_JOB_SUCCESS);
1082 }
1083
1084 static void test_blockjob_iothread_drain_subtree(void)
1085 {
1086     test_blockjob_common(BDRV_SUBTREE_DRAIN, true, TEST_JOB_SUCCESS);
1087 }
1088
1089 static void test_blockjob_iothread_error_drain_all(void)
1090 {
1091     test_blockjob_common(BDRV_DRAIN_ALL, true, TEST_JOB_FAIL_RUN);
1092     test_blockjob_common(BDRV_DRAIN_ALL, true, TEST_JOB_FAIL_PREPARE);
1093 }
1094
1095 static void test_blockjob_iothread_error_drain(void)
1096 {
1097     test_blockjob_common(BDRV_DRAIN, true, TEST_JOB_FAIL_RUN);
1098     test_blockjob_common(BDRV_DRAIN, true, TEST_JOB_FAIL_PREPARE);
1099 }
1100
1101 static void test_blockjob_iothread_error_drain_subtree(void)
1102 {
1103     test_blockjob_common(BDRV_SUBTREE_DRAIN, true, TEST_JOB_FAIL_RUN);
1104     test_blockjob_common(BDRV_SUBTREE_DRAIN, true, TEST_JOB_FAIL_PREPARE);
1105 }
1106
1107
1108 typedef struct BDRVTestTopState {
1109     BdrvChild *wait_child;
1110 } BDRVTestTopState;
1111
1112 static void bdrv_test_top_close(BlockDriverState *bs)
1113 {
1114     BdrvChild *c, *next_c;
1115     QLIST_FOREACH_SAFE(c, &bs->children, next, next_c) {
1116         bdrv_unref_child(bs, c);
1117     }
1118 }
1119
1120 static int coroutine_fn bdrv_test_top_co_preadv(BlockDriverState *bs,
1121                                                 uint64_t offset, uint64_t bytes,
1122                                                 QEMUIOVector *qiov, int flags)
1123 {
1124     BDRVTestTopState *tts = bs->opaque;
1125     return bdrv_co_preadv(tts->wait_child, offset, bytes, qiov, flags);
1126 }
1127
1128 static BlockDriver bdrv_test_top_driver = {
1129     .format_name            = "test_top_driver",
1130     .instance_size          = sizeof(BDRVTestTopState),
1131
1132     .bdrv_close             = bdrv_test_top_close,
1133     .bdrv_co_preadv         = bdrv_test_top_co_preadv,
1134
1135     .bdrv_child_perm        = bdrv_format_default_perms,
1136 };
1137
1138 typedef struct TestCoDeleteByDrainData {
1139     BlockBackend *blk;
1140     bool detach_instead_of_delete;
1141     bool done;
1142 } TestCoDeleteByDrainData;
1143
1144 static void coroutine_fn test_co_delete_by_drain(void *opaque)
1145 {
1146     TestCoDeleteByDrainData *dbdd = opaque;
1147     BlockBackend *blk = dbdd->blk;
1148     BlockDriverState *bs = blk_bs(blk);
1149     BDRVTestTopState *tts = bs->opaque;
1150     void *buffer = g_malloc(65536);
1151     QEMUIOVector qiov;
1152     struct iovec iov = {
1153         .iov_base = buffer,
1154         .iov_len  = 65536,
1155     };
1156
1157     qemu_iovec_init_external(&qiov, &iov, 1);
1158
1159     /* Pretend some internal write operation from parent to child.
1160      * Important: We have to read from the child, not from the parent!
1161      * Draining works by first propagating it all up the tree to the
1162      * root and then waiting for drainage from root to the leaves
1163      * (protocol nodes).  If we have a request waiting on the root,
1164      * everything will be drained before we go back down the tree, but
1165      * we do not want that.  We want to be in the middle of draining
1166      * when this following requests returns. */
1167     bdrv_co_preadv(tts->wait_child, 0, 65536, &qiov, 0);
1168
1169     g_assert_cmpint(bs->refcnt, ==, 1);
1170
1171     if (!dbdd->detach_instead_of_delete) {
1172         blk_unref(blk);
1173     } else {
1174         BdrvChild *c, *next_c;
1175         QLIST_FOREACH_SAFE(c, &bs->children, next, next_c) {
1176             bdrv_unref_child(bs, c);
1177         }
1178     }
1179
1180     dbdd->done = true;
1181     g_free(buffer);
1182 }
1183
1184 /**
1185  * Test what happens when some BDS has some children, you drain one of
1186  * them and this results in the BDS being deleted.
1187  *
1188  * If @detach_instead_of_delete is set, the BDS is not going to be
1189  * deleted but will only detach all of its children.
1190  */
1191 static void do_test_delete_by_drain(bool detach_instead_of_delete,
1192                                     enum drain_type drain_type)
1193 {
1194     BlockBackend *blk;
1195     BlockDriverState *bs, *child_bs, *null_bs;
1196     BDRVTestTopState *tts;
1197     TestCoDeleteByDrainData dbdd;
1198     Coroutine *co;
1199
1200     bs = bdrv_new_open_driver(&bdrv_test_top_driver, "top", BDRV_O_RDWR,
1201                               &error_abort);
1202     bs->total_sectors = 65536 >> BDRV_SECTOR_BITS;
1203     tts = bs->opaque;
1204
1205     null_bs = bdrv_open("null-co://", NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL,
1206                         &error_abort);
1207     bdrv_attach_child(bs, null_bs, "null-child", &child_file, &error_abort);
1208
1209     /* This child will be the one to pass to requests through to, and
1210      * it will stall until a drain occurs */
1211     child_bs = bdrv_new_open_driver(&bdrv_test, "child", BDRV_O_RDWR,
1212                                     &error_abort);
1213     child_bs->total_sectors = 65536 >> BDRV_SECTOR_BITS;
1214     /* Takes our reference to child_bs */
1215     tts->wait_child = bdrv_attach_child(bs, child_bs, "wait-child", &child_file,
1216                                         &error_abort);
1217
1218     /* This child is just there to be deleted
1219      * (for detach_instead_of_delete == true) */
1220     null_bs = bdrv_open("null-co://", NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL,
1221                         &error_abort);
1222     bdrv_attach_child(bs, null_bs, "null-child", &child_file, &error_abort);
1223
1224     blk = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
1225     blk_insert_bs(blk, bs, &error_abort);
1226
1227     /* Referenced by blk now */
1228     bdrv_unref(bs);
1229
1230     g_assert_cmpint(bs->refcnt, ==, 1);
1231     g_assert_cmpint(child_bs->refcnt, ==, 1);
1232     g_assert_cmpint(null_bs->refcnt, ==, 1);
1233
1234
1235     dbdd = (TestCoDeleteByDrainData){
1236         .blk = blk,
1237         .detach_instead_of_delete = detach_instead_of_delete,
1238         .done = false,
1239     };
1240     co = qemu_coroutine_create(test_co_delete_by_drain, &dbdd);
1241     qemu_coroutine_enter(co);
1242
1243     /* Drain the child while the read operation is still pending.
1244      * This should result in the operation finishing and
1245      * test_co_delete_by_drain() resuming.  Thus, @bs will be deleted
1246      * and the coroutine will exit while this drain operation is still
1247      * in progress. */
1248     switch (drain_type) {
1249     case BDRV_DRAIN:
1250         bdrv_ref(child_bs);
1251         bdrv_drain(child_bs);
1252         bdrv_unref(child_bs);
1253         break;
1254     case BDRV_SUBTREE_DRAIN:
1255         /* Would have to ref/unref bs here for !detach_instead_of_delete, but
1256          * then the whole test becomes pointless because the graph changes
1257          * don't occur during the drain any more. */
1258         assert(detach_instead_of_delete);
1259         bdrv_subtree_drained_begin(bs);
1260         bdrv_subtree_drained_end(bs);
1261         break;
1262     case BDRV_DRAIN_ALL:
1263         bdrv_drain_all_begin();
1264         bdrv_drain_all_end();
1265         break;
1266     default:
1267         g_assert_not_reached();
1268     }
1269
1270     while (!dbdd.done) {
1271         aio_poll(qemu_get_aio_context(), true);
1272     }
1273
1274     if (detach_instead_of_delete) {
1275         /* Here, the reference has not passed over to the coroutine,
1276          * so we have to delete the BB ourselves */
1277         blk_unref(blk);
1278     }
1279 }
1280
1281 static void test_delete_by_drain(void)
1282 {
1283     do_test_delete_by_drain(false, BDRV_DRAIN);
1284 }
1285
1286 static void test_detach_by_drain_all(void)
1287 {
1288     do_test_delete_by_drain(true, BDRV_DRAIN_ALL);
1289 }
1290
1291 static void test_detach_by_drain(void)
1292 {
1293     do_test_delete_by_drain(true, BDRV_DRAIN);
1294 }
1295
1296 static void test_detach_by_drain_subtree(void)
1297 {
1298     do_test_delete_by_drain(true, BDRV_SUBTREE_DRAIN);
1299 }
1300
1301
1302 struct detach_by_parent_data {
1303     BlockDriverState *parent_b;
1304     BdrvChild *child_b;
1305     BlockDriverState *c;
1306     BdrvChild *child_c;
1307     bool by_parent_cb;
1308 };
1309 static struct detach_by_parent_data detach_by_parent_data;
1310
1311 static void detach_indirect_bh(void *opaque)
1312 {
1313     struct detach_by_parent_data *data = opaque;
1314
1315     bdrv_unref_child(data->parent_b, data->child_b);
1316
1317     bdrv_ref(data->c);
1318     data->child_c = bdrv_attach_child(data->parent_b, data->c, "PB-C",
1319                                       &child_file, &error_abort);
1320 }
1321
1322 static void detach_by_parent_aio_cb(void *opaque, int ret)
1323 {
1324     struct detach_by_parent_data *data = &detach_by_parent_data;
1325
1326     g_assert_cmpint(ret, ==, 0);
1327     if (data->by_parent_cb) {
1328         detach_indirect_bh(data);
1329     }
1330 }
1331
1332 static void detach_by_driver_cb_drained_begin(BdrvChild *child)
1333 {
1334     aio_bh_schedule_oneshot(qemu_get_current_aio_context(),
1335                             detach_indirect_bh, &detach_by_parent_data);
1336     child_file.drained_begin(child);
1337 }
1338
1339 static BdrvChildRole detach_by_driver_cb_role;
1340
1341 /*
1342  * Initial graph:
1343  *
1344  * PA     PB
1345  *    \ /   \
1346  *     A     B     C
1347  *
1348  * by_parent_cb == true:  Test that parent callbacks don't poll
1349  *
1350  *     PA has a pending write request whose callback changes the child nodes of
1351  *     PB: It removes B and adds C instead. The subtree of PB is drained, which
1352  *     will indirectly drain the write request, too.
1353  *
1354  * by_parent_cb == false: Test that bdrv_drain_invoke() doesn't poll
1355  *
1356  *     PA's BdrvChildRole has a .drained_begin callback that schedules a BH
1357  *     that does the same graph change. If bdrv_drain_invoke() calls it, the
1358  *     state is messed up, but if it is only polled in the single
1359  *     BDRV_POLL_WHILE() at the end of the drain, this should work fine.
1360  */
1361 static void test_detach_indirect(bool by_parent_cb)
1362 {
1363     BlockBackend *blk;
1364     BlockDriverState *parent_a, *parent_b, *a, *b, *c;
1365     BdrvChild *child_a, *child_b;
1366     BlockAIOCB *acb;
1367
1368     QEMUIOVector qiov;
1369     struct iovec iov = {
1370         .iov_base = NULL,
1371         .iov_len = 0,
1372     };
1373     qemu_iovec_init_external(&qiov, &iov, 1);
1374
1375     if (!by_parent_cb) {
1376         detach_by_driver_cb_role = child_file;
1377         detach_by_driver_cb_role.drained_begin =
1378             detach_by_driver_cb_drained_begin;
1379     }
1380
1381     /* Create all involved nodes */
1382     parent_a = bdrv_new_open_driver(&bdrv_test, "parent-a", BDRV_O_RDWR,
1383                                     &error_abort);
1384     parent_b = bdrv_new_open_driver(&bdrv_test, "parent-b", 0,
1385                                     &error_abort);
1386
1387     a = bdrv_new_open_driver(&bdrv_test, "a", BDRV_O_RDWR, &error_abort);
1388     b = bdrv_new_open_driver(&bdrv_test, "b", BDRV_O_RDWR, &error_abort);
1389     c = bdrv_new_open_driver(&bdrv_test, "c", BDRV_O_RDWR, &error_abort);
1390
1391     /* blk is a BB for parent-a */
1392     blk = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
1393     blk_insert_bs(blk, parent_a, &error_abort);
1394     bdrv_unref(parent_a);
1395
1396     /* If we want to get bdrv_drain_invoke() to call aio_poll(), the driver
1397      * callback must not return immediately. */
1398     if (!by_parent_cb) {
1399         BDRVTestState *s = parent_a->opaque;
1400         s->sleep_in_drain_begin = true;
1401     }
1402
1403     /* Set child relationships */
1404     bdrv_ref(b);
1405     bdrv_ref(a);
1406     child_b = bdrv_attach_child(parent_b, b, "PB-B", &child_file, &error_abort);
1407     child_a = bdrv_attach_child(parent_b, a, "PB-A", &child_backing, &error_abort);
1408
1409     bdrv_ref(a);
1410     bdrv_attach_child(parent_a, a, "PA-A",
1411                       by_parent_cb ? &child_file : &detach_by_driver_cb_role,
1412                       &error_abort);
1413
1414     g_assert_cmpint(parent_a->refcnt, ==, 1);
1415     g_assert_cmpint(parent_b->refcnt, ==, 1);
1416     g_assert_cmpint(a->refcnt, ==, 3);
1417     g_assert_cmpint(b->refcnt, ==, 2);
1418     g_assert_cmpint(c->refcnt, ==, 1);
1419
1420     g_assert(QLIST_FIRST(&parent_b->children) == child_a);
1421     g_assert(QLIST_NEXT(child_a, next) == child_b);
1422     g_assert(QLIST_NEXT(child_b, next) == NULL);
1423
1424     /* Start the evil write request */
1425     detach_by_parent_data = (struct detach_by_parent_data) {
1426         .parent_b = parent_b,
1427         .child_b = child_b,
1428         .c = c,
1429         .by_parent_cb = by_parent_cb,
1430     };
1431     acb = blk_aio_preadv(blk, 0, &qiov, 0, detach_by_parent_aio_cb, NULL);
1432     g_assert(acb != NULL);
1433
1434     /* Drain and check the expected result */
1435     bdrv_subtree_drained_begin(parent_b);
1436
1437     g_assert(detach_by_parent_data.child_c != NULL);
1438
1439     g_assert_cmpint(parent_a->refcnt, ==, 1);
1440     g_assert_cmpint(parent_b->refcnt, ==, 1);
1441     g_assert_cmpint(a->refcnt, ==, 3);
1442     g_assert_cmpint(b->refcnt, ==, 1);
1443     g_assert_cmpint(c->refcnt, ==, 2);
1444
1445     g_assert(QLIST_FIRST(&parent_b->children) == detach_by_parent_data.child_c);
1446     g_assert(QLIST_NEXT(detach_by_parent_data.child_c, next) == child_a);
1447     g_assert(QLIST_NEXT(child_a, next) == NULL);
1448
1449     g_assert_cmpint(parent_a->quiesce_counter, ==, 1);
1450     g_assert_cmpint(parent_b->quiesce_counter, ==, 1);
1451     g_assert_cmpint(a->quiesce_counter, ==, 1);
1452     g_assert_cmpint(b->quiesce_counter, ==, 0);
1453     g_assert_cmpint(c->quiesce_counter, ==, 1);
1454
1455     bdrv_subtree_drained_end(parent_b);
1456
1457     bdrv_unref(parent_b);
1458     blk_unref(blk);
1459
1460     /* XXX Once bdrv_close() unref's children instead of just detaching them,
1461      * this won't be necessary any more. */
1462     bdrv_unref(a);
1463     bdrv_unref(a);
1464     bdrv_unref(c);
1465
1466     g_assert_cmpint(a->refcnt, ==, 1);
1467     g_assert_cmpint(b->refcnt, ==, 1);
1468     g_assert_cmpint(c->refcnt, ==, 1);
1469     bdrv_unref(a);
1470     bdrv_unref(b);
1471     bdrv_unref(c);
1472 }
1473
1474 static void test_detach_by_parent_cb(void)
1475 {
1476     test_detach_indirect(true);
1477 }
1478
1479 static void test_detach_by_driver_cb(void)
1480 {
1481     test_detach_indirect(false);
1482 }
1483
1484 static void test_append_to_drained(void)
1485 {
1486     BlockBackend *blk;
1487     BlockDriverState *base, *overlay;
1488     BDRVTestState *base_s, *overlay_s;
1489
1490     blk = blk_new(BLK_PERM_ALL, BLK_PERM_ALL);
1491     base = bdrv_new_open_driver(&bdrv_test, "base", BDRV_O_RDWR, &error_abort);
1492     base_s = base->opaque;
1493     blk_insert_bs(blk, base, &error_abort);
1494
1495     overlay = bdrv_new_open_driver(&bdrv_test, "overlay", BDRV_O_RDWR,
1496                                    &error_abort);
1497     overlay_s = overlay->opaque;
1498
1499     do_drain_begin(BDRV_DRAIN, base);
1500     g_assert_cmpint(base->quiesce_counter, ==, 1);
1501     g_assert_cmpint(base_s->drain_count, ==, 1);
1502     g_assert_cmpint(base->in_flight, ==, 0);
1503
1504     /* Takes ownership of overlay, so we don't have to unref it later */
1505     bdrv_append(overlay, base, &error_abort);
1506     g_assert_cmpint(base->in_flight, ==, 0);
1507     g_assert_cmpint(overlay->in_flight, ==, 0);
1508
1509     g_assert_cmpint(base->quiesce_counter, ==, 1);
1510     g_assert_cmpint(base_s->drain_count, ==, 1);
1511     g_assert_cmpint(overlay->quiesce_counter, ==, 1);
1512     g_assert_cmpint(overlay_s->drain_count, ==, 1);
1513
1514     do_drain_end(BDRV_DRAIN, base);
1515
1516     g_assert_cmpint(base->quiesce_counter, ==, 0);
1517     g_assert_cmpint(base_s->drain_count, ==, 0);
1518     g_assert_cmpint(overlay->quiesce_counter, ==, 0);
1519     g_assert_cmpint(overlay_s->drain_count, ==, 0);
1520
1521     bdrv_unref(base);
1522     blk_unref(blk);
1523 }
1524
1525 int main(int argc, char **argv)
1526 {
1527     int ret;
1528
1529     bdrv_init();
1530     qemu_init_main_loop(&error_abort);
1531
1532     g_test_init(&argc, &argv, NULL);
1533     qemu_event_init(&done_event, false);
1534
1535     g_test_add_func("/bdrv-drain/driver-cb/drain_all", test_drv_cb_drain_all);
1536     g_test_add_func("/bdrv-drain/driver-cb/drain", test_drv_cb_drain);
1537     g_test_add_func("/bdrv-drain/driver-cb/drain_subtree",
1538                     test_drv_cb_drain_subtree);
1539
1540     g_test_add_func("/bdrv-drain/driver-cb/co/drain_all",
1541                     test_drv_cb_co_drain_all);
1542     g_test_add_func("/bdrv-drain/driver-cb/co/drain", test_drv_cb_co_drain);
1543     g_test_add_func("/bdrv-drain/driver-cb/co/drain_subtree",
1544                     test_drv_cb_co_drain_subtree);
1545
1546
1547     g_test_add_func("/bdrv-drain/quiesce/drain_all", test_quiesce_drain_all);
1548     g_test_add_func("/bdrv-drain/quiesce/drain", test_quiesce_drain);
1549     g_test_add_func("/bdrv-drain/quiesce/drain_subtree",
1550                     test_quiesce_drain_subtree);
1551
1552     g_test_add_func("/bdrv-drain/quiesce/co/drain_all",
1553                     test_quiesce_co_drain_all);
1554     g_test_add_func("/bdrv-drain/quiesce/co/drain", test_quiesce_co_drain);
1555     g_test_add_func("/bdrv-drain/quiesce/co/drain_subtree",
1556                     test_quiesce_co_drain_subtree);
1557
1558     g_test_add_func("/bdrv-drain/nested", test_nested);
1559     g_test_add_func("/bdrv-drain/multiparent", test_multiparent);
1560
1561     g_test_add_func("/bdrv-drain/graph-change/drain_subtree",
1562                     test_graph_change_drain_subtree);
1563     g_test_add_func("/bdrv-drain/graph-change/drain_all",
1564                     test_graph_change_drain_all);
1565
1566     g_test_add_func("/bdrv-drain/iothread/drain_all", test_iothread_drain_all);
1567     g_test_add_func("/bdrv-drain/iothread/drain", test_iothread_drain);
1568     g_test_add_func("/bdrv-drain/iothread/drain_subtree",
1569                     test_iothread_drain_subtree);
1570
1571     g_test_add_func("/bdrv-drain/blockjob/drain_all", test_blockjob_drain_all);
1572     g_test_add_func("/bdrv-drain/blockjob/drain", test_blockjob_drain);
1573     g_test_add_func("/bdrv-drain/blockjob/drain_subtree",
1574                     test_blockjob_drain_subtree);
1575
1576     g_test_add_func("/bdrv-drain/blockjob/error/drain_all",
1577                     test_blockjob_error_drain_all);
1578     g_test_add_func("/bdrv-drain/blockjob/error/drain",
1579                     test_blockjob_error_drain);
1580     g_test_add_func("/bdrv-drain/blockjob/error/drain_subtree",
1581                     test_blockjob_error_drain_subtree);
1582
1583     g_test_add_func("/bdrv-drain/blockjob/iothread/drain_all",
1584                     test_blockjob_iothread_drain_all);
1585     g_test_add_func("/bdrv-drain/blockjob/iothread/drain",
1586                     test_blockjob_iothread_drain);
1587     g_test_add_func("/bdrv-drain/blockjob/iothread/drain_subtree",
1588                     test_blockjob_iothread_drain_subtree);
1589
1590     g_test_add_func("/bdrv-drain/blockjob/iothread/error/drain_all",
1591                     test_blockjob_iothread_error_drain_all);
1592     g_test_add_func("/bdrv-drain/blockjob/iothread/error/drain",
1593                     test_blockjob_iothread_error_drain);
1594     g_test_add_func("/bdrv-drain/blockjob/iothread/error/drain_subtree",
1595                     test_blockjob_iothread_error_drain_subtree);
1596
1597     g_test_add_func("/bdrv-drain/deletion/drain", test_delete_by_drain);
1598     g_test_add_func("/bdrv-drain/detach/drain_all", test_detach_by_drain_all);
1599     g_test_add_func("/bdrv-drain/detach/drain", test_detach_by_drain);
1600     g_test_add_func("/bdrv-drain/detach/drain_subtree", test_detach_by_drain_subtree);
1601     g_test_add_func("/bdrv-drain/detach/parent_cb", test_detach_by_parent_cb);
1602     g_test_add_func("/bdrv-drain/detach/driver_cb", test_detach_by_driver_cb);
1603
1604     g_test_add_func("/bdrv-drain/attach/drain", test_append_to_drained);
1605
1606     ret = g_test_run();
1607     qemu_event_destroy(&done_event);
1608     return ret;
1609 }