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_int.h" 27 #include "block/blockjob_int.h" 28 #include "sysemu/block-backend.h" 29 #include "qapi/error.h" 30 #include "qemu/main-loop.h" 31 #include "iothread.h" 32 33 static QemuEvent done_event; 34 35 typedef struct BDRVTestState { 36 int drain_count; 37 AioContext *bh_indirection_ctx; 38 bool sleep_in_drain_begin; 39 } BDRVTestState; 40 41 static void coroutine_fn sleep_in_drain_begin(void *opaque) 42 { 43 BlockDriverState *bs = opaque; 44 45 qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, 100000); 46 bdrv_dec_in_flight(bs); 47 } 48 49 static void bdrv_test_drain_begin(BlockDriverState *bs) 50 { 51 BDRVTestState *s = bs->opaque; 52 s->drain_count++; 53 if (s->sleep_in_drain_begin) { 54 Coroutine *co = qemu_coroutine_create(sleep_in_drain_begin, bs); 55 bdrv_inc_in_flight(bs); 56 aio_co_enter(bdrv_get_aio_context(bs), co); 57 } 58 } 59 60 static void bdrv_test_drain_end(BlockDriverState *bs) 61 { 62 BDRVTestState *s = bs->opaque; 63 s->drain_count--; 64 } 65 66 static void bdrv_test_close(BlockDriverState *bs) 67 { 68 BDRVTestState *s = bs->opaque; 69 g_assert_cmpint(s->drain_count, >, 0); 70 } 71 72 static void co_reenter_bh(void *opaque) 73 { 74 aio_co_wake(opaque); 75 } 76 77 static int coroutine_fn bdrv_test_co_preadv(BlockDriverState *bs, 78 int64_t offset, int64_t bytes, 79 QEMUIOVector *qiov, 80 BdrvRequestFlags flags) 81 { 82 BDRVTestState *s = bs->opaque; 83 84 /* We want this request to stay until the polling loop in drain waits for 85 * it to complete. We need to sleep a while as bdrv_drain_invoke() comes 86 * first and polls its result, too, but it shouldn't accidentally complete 87 * this request yet. */ 88 qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, 100000); 89 90 if (s->bh_indirection_ctx) { 91 aio_bh_schedule_oneshot(s->bh_indirection_ctx, co_reenter_bh, 92 qemu_coroutine_self()); 93 qemu_coroutine_yield(); 94 } 95 96 return 0; 97 } 98 99 static int bdrv_test_change_backing_file(BlockDriverState *bs, 100 const char *backing_file, 101 const char *backing_fmt) 102 { 103 return 0; 104 } 105 106 static BlockDriver bdrv_test = { 107 .format_name = "test", 108 .instance_size = sizeof(BDRVTestState), 109 .supports_backing = true, 110 111 .bdrv_close = bdrv_test_close, 112 .bdrv_co_preadv = bdrv_test_co_preadv, 113 114 .bdrv_drain_begin = bdrv_test_drain_begin, 115 .bdrv_drain_end = bdrv_test_drain_end, 116 117 .bdrv_child_perm = bdrv_default_perms, 118 119 .bdrv_change_backing_file = bdrv_test_change_backing_file, 120 }; 121 122 static void aio_ret_cb(void *opaque, int ret) 123 { 124 int *aio_ret = opaque; 125 *aio_ret = ret; 126 } 127 128 typedef struct CallInCoroutineData { 129 void (*entry)(void); 130 bool done; 131 } CallInCoroutineData; 132 133 static coroutine_fn void call_in_coroutine_entry(void *opaque) 134 { 135 CallInCoroutineData *data = opaque; 136 137 data->entry(); 138 data->done = true; 139 } 140 141 static void call_in_coroutine(void (*entry)(void)) 142 { 143 Coroutine *co; 144 CallInCoroutineData data = { 145 .entry = entry, 146 .done = false, 147 }; 148 149 co = qemu_coroutine_create(call_in_coroutine_entry, &data); 150 qemu_coroutine_enter(co); 151 while (!data.done) { 152 aio_poll(qemu_get_aio_context(), true); 153 } 154 } 155 156 enum drain_type { 157 BDRV_DRAIN_ALL, 158 BDRV_DRAIN, 159 DRAIN_TYPE_MAX, 160 }; 161 162 static void do_drain_begin(enum drain_type drain_type, BlockDriverState *bs) 163 { 164 switch (drain_type) { 165 case BDRV_DRAIN_ALL: bdrv_drain_all_begin(); break; 166 case BDRV_DRAIN: bdrv_drained_begin(bs); break; 167 default: g_assert_not_reached(); 168 } 169 } 170 171 static void do_drain_end(enum drain_type drain_type, BlockDriverState *bs) 172 { 173 switch (drain_type) { 174 case BDRV_DRAIN_ALL: bdrv_drain_all_end(); break; 175 case BDRV_DRAIN: bdrv_drained_end(bs); break; 176 default: g_assert_not_reached(); 177 } 178 } 179 180 static void do_drain_begin_unlocked(enum drain_type drain_type, BlockDriverState *bs) 181 { 182 if (drain_type != BDRV_DRAIN_ALL) { 183 aio_context_acquire(bdrv_get_aio_context(bs)); 184 } 185 do_drain_begin(drain_type, bs); 186 if (drain_type != BDRV_DRAIN_ALL) { 187 aio_context_release(bdrv_get_aio_context(bs)); 188 } 189 } 190 191 static BlockBackend * no_coroutine_fn test_setup(void) 192 { 193 BlockBackend *blk; 194 BlockDriverState *bs, *backing; 195 196 blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL); 197 bs = bdrv_new_open_driver(&bdrv_test, "test-node", BDRV_O_RDWR, 198 &error_abort); 199 blk_insert_bs(blk, bs, &error_abort); 200 201 backing = bdrv_new_open_driver(&bdrv_test, "backing", 0, &error_abort); 202 bdrv_set_backing_hd(bs, backing, &error_abort); 203 204 bdrv_unref(backing); 205 bdrv_unref(bs); 206 207 return blk; 208 } 209 210 static void do_drain_end_unlocked(enum drain_type drain_type, BlockDriverState *bs) 211 { 212 if (drain_type != BDRV_DRAIN_ALL) { 213 aio_context_acquire(bdrv_get_aio_context(bs)); 214 } 215 do_drain_end(drain_type, bs); 216 if (drain_type != BDRV_DRAIN_ALL) { 217 aio_context_release(bdrv_get_aio_context(bs)); 218 } 219 } 220 221 static void test_drv_cb_common(BlockBackend *blk, enum drain_type drain_type, 222 bool recursive) 223 { 224 BlockDriverState *bs = blk_bs(blk); 225 BlockDriverState *backing = bs->backing->bs; 226 BDRVTestState *s, *backing_s; 227 BlockAIOCB *acb; 228 int aio_ret; 229 230 QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, NULL, 0); 231 232 s = bs->opaque; 233 backing_s = backing->opaque; 234 235 /* Simple bdrv_drain_all_begin/end pair, check that CBs are called */ 236 g_assert_cmpint(s->drain_count, ==, 0); 237 g_assert_cmpint(backing_s->drain_count, ==, 0); 238 239 do_drain_begin(drain_type, bs); 240 241 g_assert_cmpint(s->drain_count, ==, 1); 242 g_assert_cmpint(backing_s->drain_count, ==, !!recursive); 243 244 do_drain_end(drain_type, bs); 245 246 g_assert_cmpint(s->drain_count, ==, 0); 247 g_assert_cmpint(backing_s->drain_count, ==, 0); 248 249 /* Now do the same while a request is pending */ 250 aio_ret = -EINPROGRESS; 251 acb = blk_aio_preadv(blk, 0, &qiov, 0, aio_ret_cb, &aio_ret); 252 g_assert(acb != NULL); 253 g_assert_cmpint(aio_ret, ==, -EINPROGRESS); 254 255 g_assert_cmpint(s->drain_count, ==, 0); 256 g_assert_cmpint(backing_s->drain_count, ==, 0); 257 258 do_drain_begin(drain_type, bs); 259 260 g_assert_cmpint(aio_ret, ==, 0); 261 g_assert_cmpint(s->drain_count, ==, 1); 262 g_assert_cmpint(backing_s->drain_count, ==, !!recursive); 263 264 do_drain_end(drain_type, bs); 265 266 g_assert_cmpint(s->drain_count, ==, 0); 267 g_assert_cmpint(backing_s->drain_count, ==, 0); 268 } 269 270 static void test_drv_cb_drain_all(void) 271 { 272 BlockBackend *blk = test_setup(); 273 test_drv_cb_common(blk, BDRV_DRAIN_ALL, true); 274 blk_unref(blk); 275 } 276 277 static void test_drv_cb_drain(void) 278 { 279 BlockBackend *blk = test_setup(); 280 test_drv_cb_common(blk, BDRV_DRAIN, false); 281 blk_unref(blk); 282 } 283 284 static void coroutine_fn test_drv_cb_co_drain_all_entry(void) 285 { 286 BlockBackend *blk = blk_all_next(NULL); 287 test_drv_cb_common(blk, BDRV_DRAIN_ALL, true); 288 } 289 290 static void test_drv_cb_co_drain_all(void) 291 { 292 BlockBackend *blk = test_setup(); 293 call_in_coroutine(test_drv_cb_co_drain_all_entry); 294 blk_unref(blk); 295 } 296 297 static void coroutine_fn test_drv_cb_co_drain_entry(void) 298 { 299 BlockBackend *blk = blk_all_next(NULL); 300 test_drv_cb_common(blk, BDRV_DRAIN, false); 301 } 302 303 static void test_drv_cb_co_drain(void) 304 { 305 BlockBackend *blk = test_setup(); 306 call_in_coroutine(test_drv_cb_co_drain_entry); 307 blk_unref(blk); 308 } 309 310 static void test_quiesce_common(BlockBackend *blk, enum drain_type drain_type, 311 bool recursive) 312 { 313 BlockDriverState *bs = blk_bs(blk); 314 BlockDriverState *backing = bs->backing->bs; 315 316 g_assert_cmpint(bs->quiesce_counter, ==, 0); 317 g_assert_cmpint(backing->quiesce_counter, ==, 0); 318 319 do_drain_begin(drain_type, bs); 320 321 if (drain_type == BDRV_DRAIN_ALL) { 322 g_assert_cmpint(bs->quiesce_counter, ==, 2); 323 } else { 324 g_assert_cmpint(bs->quiesce_counter, ==, 1); 325 } 326 g_assert_cmpint(backing->quiesce_counter, ==, !!recursive); 327 328 do_drain_end(drain_type, bs); 329 330 g_assert_cmpint(bs->quiesce_counter, ==, 0); 331 g_assert_cmpint(backing->quiesce_counter, ==, 0); 332 } 333 334 static void test_quiesce_drain_all(void) 335 { 336 BlockBackend *blk = test_setup(); 337 test_quiesce_common(blk, BDRV_DRAIN_ALL, true); 338 blk_unref(blk); 339 } 340 341 static void test_quiesce_drain(void) 342 { 343 BlockBackend *blk = test_setup(); 344 test_quiesce_common(blk, BDRV_DRAIN, false); 345 blk_unref(blk); 346 } 347 348 static void coroutine_fn test_quiesce_co_drain_all_entry(void) 349 { 350 BlockBackend *blk = blk_all_next(NULL); 351 test_quiesce_common(blk, BDRV_DRAIN_ALL, true); 352 } 353 354 static void test_quiesce_co_drain_all(void) 355 { 356 BlockBackend *blk = test_setup(); 357 call_in_coroutine(test_quiesce_co_drain_all_entry); 358 blk_unref(blk); 359 } 360 361 static void coroutine_fn test_quiesce_co_drain_entry(void) 362 { 363 BlockBackend *blk = blk_all_next(NULL); 364 test_quiesce_common(blk, BDRV_DRAIN, false); 365 } 366 367 static void test_quiesce_co_drain(void) 368 { 369 BlockBackend *blk = test_setup(); 370 call_in_coroutine(test_quiesce_co_drain_entry); 371 blk_unref(blk); 372 } 373 374 static void test_nested(void) 375 { 376 BlockBackend *blk; 377 BlockDriverState *bs, *backing; 378 BDRVTestState *s, *backing_s; 379 enum drain_type outer, inner; 380 381 blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL); 382 bs = bdrv_new_open_driver(&bdrv_test, "test-node", BDRV_O_RDWR, 383 &error_abort); 384 s = bs->opaque; 385 blk_insert_bs(blk, bs, &error_abort); 386 387 backing = bdrv_new_open_driver(&bdrv_test, "backing", 0, &error_abort); 388 backing_s = backing->opaque; 389 bdrv_set_backing_hd(bs, backing, &error_abort); 390 391 for (outer = 0; outer < DRAIN_TYPE_MAX; outer++) { 392 for (inner = 0; inner < DRAIN_TYPE_MAX; inner++) { 393 int backing_quiesce = (outer == BDRV_DRAIN_ALL) + 394 (inner == BDRV_DRAIN_ALL); 395 396 g_assert_cmpint(bs->quiesce_counter, ==, 0); 397 g_assert_cmpint(backing->quiesce_counter, ==, 0); 398 g_assert_cmpint(s->drain_count, ==, 0); 399 g_assert_cmpint(backing_s->drain_count, ==, 0); 400 401 do_drain_begin(outer, bs); 402 do_drain_begin(inner, bs); 403 404 g_assert_cmpint(bs->quiesce_counter, ==, 2 + !!backing_quiesce); 405 g_assert_cmpint(backing->quiesce_counter, ==, backing_quiesce); 406 g_assert_cmpint(s->drain_count, ==, 1); 407 g_assert_cmpint(backing_s->drain_count, ==, !!backing_quiesce); 408 409 do_drain_end(inner, bs); 410 do_drain_end(outer, bs); 411 412 g_assert_cmpint(bs->quiesce_counter, ==, 0); 413 g_assert_cmpint(backing->quiesce_counter, ==, 0); 414 g_assert_cmpint(s->drain_count, ==, 0); 415 g_assert_cmpint(backing_s->drain_count, ==, 0); 416 } 417 } 418 419 bdrv_unref(backing); 420 bdrv_unref(bs); 421 blk_unref(blk); 422 } 423 424 static void test_graph_change_drain_all(void) 425 { 426 BlockBackend *blk_a, *blk_b; 427 BlockDriverState *bs_a, *bs_b; 428 BDRVTestState *a_s, *b_s; 429 430 /* Create node A with a BlockBackend */ 431 blk_a = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL); 432 bs_a = bdrv_new_open_driver(&bdrv_test, "test-node-a", BDRV_O_RDWR, 433 &error_abort); 434 a_s = bs_a->opaque; 435 blk_insert_bs(blk_a, bs_a, &error_abort); 436 437 g_assert_cmpint(bs_a->quiesce_counter, ==, 0); 438 g_assert_cmpint(a_s->drain_count, ==, 0); 439 440 /* Call bdrv_drain_all_begin() */ 441 bdrv_drain_all_begin(); 442 443 g_assert_cmpint(bs_a->quiesce_counter, ==, 1); 444 g_assert_cmpint(a_s->drain_count, ==, 1); 445 446 /* Create node B with a BlockBackend */ 447 blk_b = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL); 448 bs_b = bdrv_new_open_driver(&bdrv_test, "test-node-b", BDRV_O_RDWR, 449 &error_abort); 450 b_s = bs_b->opaque; 451 blk_insert_bs(blk_b, bs_b, &error_abort); 452 453 g_assert_cmpint(bs_a->quiesce_counter, ==, 1); 454 g_assert_cmpint(bs_b->quiesce_counter, ==, 1); 455 g_assert_cmpint(a_s->drain_count, ==, 1); 456 g_assert_cmpint(b_s->drain_count, ==, 1); 457 458 /* Unref and finally delete node A */ 459 blk_unref(blk_a); 460 461 g_assert_cmpint(bs_a->quiesce_counter, ==, 1); 462 g_assert_cmpint(bs_b->quiesce_counter, ==, 1); 463 g_assert_cmpint(a_s->drain_count, ==, 1); 464 g_assert_cmpint(b_s->drain_count, ==, 1); 465 466 bdrv_unref(bs_a); 467 468 g_assert_cmpint(bs_b->quiesce_counter, ==, 1); 469 g_assert_cmpint(b_s->drain_count, ==, 1); 470 471 /* End the drained section */ 472 bdrv_drain_all_end(); 473 474 g_assert_cmpint(bs_b->quiesce_counter, ==, 0); 475 g_assert_cmpint(b_s->drain_count, ==, 0); 476 477 bdrv_unref(bs_b); 478 blk_unref(blk_b); 479 } 480 481 struct test_iothread_data { 482 BlockDriverState *bs; 483 enum drain_type drain_type; 484 int *aio_ret; 485 bool co_done; 486 }; 487 488 static void coroutine_fn test_iothread_drain_co_entry(void *opaque) 489 { 490 struct test_iothread_data *data = opaque; 491 492 do_drain_begin(data->drain_type, data->bs); 493 g_assert_cmpint(*data->aio_ret, ==, 0); 494 do_drain_end(data->drain_type, data->bs); 495 496 data->co_done = true; 497 aio_wait_kick(); 498 } 499 500 static void test_iothread_aio_cb(void *opaque, int ret) 501 { 502 int *aio_ret = opaque; 503 *aio_ret = ret; 504 qemu_event_set(&done_event); 505 } 506 507 static void test_iothread_main_thread_bh(void *opaque) 508 { 509 struct test_iothread_data *data = opaque; 510 511 /* Test that the AioContext is not yet locked in a random BH that is 512 * executed during drain, otherwise this would deadlock. */ 513 aio_context_acquire(bdrv_get_aio_context(data->bs)); 514 bdrv_flush(data->bs); 515 bdrv_dec_in_flight(data->bs); /* incremented by test_iothread_common() */ 516 aio_context_release(bdrv_get_aio_context(data->bs)); 517 } 518 519 /* 520 * Starts an AIO request on a BDS that runs in the AioContext of iothread 1. 521 * The request involves a BH on iothread 2 before it can complete. 522 * 523 * @drain_thread = 0 means that do_drain_begin/end are called from the main 524 * thread, @drain_thread = 1 means that they are called from iothread 1. Drain 525 * for this BDS cannot be called from iothread 2 because only the main thread 526 * may do cross-AioContext polling. 527 */ 528 static void test_iothread_common(enum drain_type drain_type, int drain_thread) 529 { 530 BlockBackend *blk; 531 BlockDriverState *bs; 532 BDRVTestState *s; 533 BlockAIOCB *acb; 534 Coroutine *co; 535 int aio_ret; 536 struct test_iothread_data data; 537 538 IOThread *a = iothread_new(); 539 IOThread *b = iothread_new(); 540 AioContext *ctx_a = iothread_get_aio_context(a); 541 AioContext *ctx_b = iothread_get_aio_context(b); 542 543 QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, NULL, 0); 544 545 /* bdrv_drain_all() may only be called from the main loop thread */ 546 if (drain_type == BDRV_DRAIN_ALL && drain_thread != 0) { 547 goto out; 548 } 549 550 blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL); 551 bs = bdrv_new_open_driver(&bdrv_test, "test-node", BDRV_O_RDWR, 552 &error_abort); 553 s = bs->opaque; 554 blk_insert_bs(blk, bs, &error_abort); 555 blk_set_disable_request_queuing(blk, true); 556 557 blk_set_aio_context(blk, ctx_a, &error_abort); 558 aio_context_acquire(ctx_a); 559 560 s->bh_indirection_ctx = ctx_b; 561 562 aio_ret = -EINPROGRESS; 563 qemu_event_reset(&done_event); 564 565 if (drain_thread == 0) { 566 acb = blk_aio_preadv(blk, 0, &qiov, 0, test_iothread_aio_cb, &aio_ret); 567 } else { 568 acb = blk_aio_preadv(blk, 0, &qiov, 0, aio_ret_cb, &aio_ret); 569 } 570 g_assert(acb != NULL); 571 g_assert_cmpint(aio_ret, ==, -EINPROGRESS); 572 573 aio_context_release(ctx_a); 574 575 data = (struct test_iothread_data) { 576 .bs = bs, 577 .drain_type = drain_type, 578 .aio_ret = &aio_ret, 579 }; 580 581 switch (drain_thread) { 582 case 0: 583 if (drain_type != BDRV_DRAIN_ALL) { 584 aio_context_acquire(ctx_a); 585 } 586 587 /* 588 * Increment in_flight so that do_drain_begin() waits for 589 * test_iothread_main_thread_bh(). This prevents the race between 590 * test_iothread_main_thread_bh() in IOThread a and do_drain_begin() in 591 * this thread. test_iothread_main_thread_bh() decrements in_flight. 592 */ 593 bdrv_inc_in_flight(bs); 594 aio_bh_schedule_oneshot(ctx_a, test_iothread_main_thread_bh, &data); 595 596 /* The request is running on the IOThread a. Draining its block device 597 * will make sure that it has completed as far as the BDS is concerned, 598 * but the drain in this thread can continue immediately after 599 * bdrv_dec_in_flight() and aio_ret might be assigned only slightly 600 * later. */ 601 do_drain_begin(drain_type, bs); 602 g_assert_cmpint(bs->in_flight, ==, 0); 603 604 if (drain_type != BDRV_DRAIN_ALL) { 605 aio_context_release(ctx_a); 606 } 607 qemu_event_wait(&done_event); 608 if (drain_type != BDRV_DRAIN_ALL) { 609 aio_context_acquire(ctx_a); 610 } 611 612 g_assert_cmpint(aio_ret, ==, 0); 613 do_drain_end(drain_type, bs); 614 615 if (drain_type != BDRV_DRAIN_ALL) { 616 aio_context_release(ctx_a); 617 } 618 break; 619 case 1: 620 co = qemu_coroutine_create(test_iothread_drain_co_entry, &data); 621 aio_co_enter(ctx_a, co); 622 AIO_WAIT_WHILE_UNLOCKED(NULL, !data.co_done); 623 break; 624 default: 625 g_assert_not_reached(); 626 } 627 628 aio_context_acquire(ctx_a); 629 blk_set_aio_context(blk, qemu_get_aio_context(), &error_abort); 630 aio_context_release(ctx_a); 631 632 bdrv_unref(bs); 633 blk_unref(blk); 634 635 out: 636 iothread_join(a); 637 iothread_join(b); 638 } 639 640 static void test_iothread_drain_all(void) 641 { 642 test_iothread_common(BDRV_DRAIN_ALL, 0); 643 test_iothread_common(BDRV_DRAIN_ALL, 1); 644 } 645 646 static void test_iothread_drain(void) 647 { 648 test_iothread_common(BDRV_DRAIN, 0); 649 test_iothread_common(BDRV_DRAIN, 1); 650 } 651 652 653 typedef struct TestBlockJob { 654 BlockJob common; 655 BlockDriverState *bs; 656 int run_ret; 657 int prepare_ret; 658 bool running; 659 bool should_complete; 660 } TestBlockJob; 661 662 static int test_job_prepare(Job *job) 663 { 664 TestBlockJob *s = container_of(job, TestBlockJob, common.job); 665 666 /* Provoke an AIO_WAIT_WHILE() call to verify there is no deadlock */ 667 bdrv_flush(s->bs); 668 return s->prepare_ret; 669 } 670 671 static void test_job_commit(Job *job) 672 { 673 TestBlockJob *s = container_of(job, TestBlockJob, common.job); 674 675 /* Provoke an AIO_WAIT_WHILE() call to verify there is no deadlock */ 676 bdrv_flush(s->bs); 677 } 678 679 static void test_job_abort(Job *job) 680 { 681 TestBlockJob *s = container_of(job, TestBlockJob, common.job); 682 683 /* Provoke an AIO_WAIT_WHILE() call to verify there is no deadlock */ 684 bdrv_flush(s->bs); 685 } 686 687 static int coroutine_fn test_job_run(Job *job, Error **errp) 688 { 689 TestBlockJob *s = container_of(job, TestBlockJob, common.job); 690 691 /* We are running the actual job code past the pause point in 692 * job_co_entry(). */ 693 s->running = true; 694 695 job_transition_to_ready(&s->common.job); 696 while (!s->should_complete) { 697 /* Avoid job_sleep_ns() because it marks the job as !busy. We want to 698 * emulate some actual activity (probably some I/O) here so that drain 699 * has to wait for this activity to stop. */ 700 qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, 1000000); 701 702 job_pause_point(&s->common.job); 703 } 704 705 return s->run_ret; 706 } 707 708 static void test_job_complete(Job *job, Error **errp) 709 { 710 TestBlockJob *s = container_of(job, TestBlockJob, common.job); 711 s->should_complete = true; 712 } 713 714 BlockJobDriver test_job_driver = { 715 .job_driver = { 716 .instance_size = sizeof(TestBlockJob), 717 .free = block_job_free, 718 .user_resume = block_job_user_resume, 719 .run = test_job_run, 720 .complete = test_job_complete, 721 .prepare = test_job_prepare, 722 .commit = test_job_commit, 723 .abort = test_job_abort, 724 }, 725 }; 726 727 enum test_job_result { 728 TEST_JOB_SUCCESS, 729 TEST_JOB_FAIL_RUN, 730 TEST_JOB_FAIL_PREPARE, 731 }; 732 733 enum test_job_drain_node { 734 TEST_JOB_DRAIN_SRC, 735 TEST_JOB_DRAIN_SRC_CHILD, 736 }; 737 738 static void test_blockjob_common_drain_node(enum drain_type drain_type, 739 bool use_iothread, 740 enum test_job_result result, 741 enum test_job_drain_node drain_node) 742 { 743 BlockBackend *blk_src, *blk_target; 744 BlockDriverState *src, *src_backing, *src_overlay, *target, *drain_bs; 745 BlockJob *job; 746 TestBlockJob *tjob; 747 IOThread *iothread = NULL; 748 AioContext *ctx; 749 int ret; 750 751 src = bdrv_new_open_driver(&bdrv_test, "source", BDRV_O_RDWR, 752 &error_abort); 753 src_backing = bdrv_new_open_driver(&bdrv_test, "source-backing", 754 BDRV_O_RDWR, &error_abort); 755 src_overlay = bdrv_new_open_driver(&bdrv_test, "source-overlay", 756 BDRV_O_RDWR, &error_abort); 757 758 bdrv_set_backing_hd(src_overlay, src, &error_abort); 759 bdrv_unref(src); 760 bdrv_set_backing_hd(src, src_backing, &error_abort); 761 bdrv_unref(src_backing); 762 763 blk_src = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL); 764 blk_insert_bs(blk_src, src_overlay, &error_abort); 765 766 switch (drain_node) { 767 case TEST_JOB_DRAIN_SRC: 768 drain_bs = src; 769 break; 770 case TEST_JOB_DRAIN_SRC_CHILD: 771 drain_bs = src_backing; 772 break; 773 default: 774 g_assert_not_reached(); 775 } 776 777 if (use_iothread) { 778 iothread = iothread_new(); 779 ctx = iothread_get_aio_context(iothread); 780 blk_set_aio_context(blk_src, ctx, &error_abort); 781 } else { 782 ctx = qemu_get_aio_context(); 783 } 784 785 target = bdrv_new_open_driver(&bdrv_test, "target", BDRV_O_RDWR, 786 &error_abort); 787 blk_target = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL); 788 blk_insert_bs(blk_target, target, &error_abort); 789 blk_set_allow_aio_context_change(blk_target, true); 790 791 aio_context_acquire(ctx); 792 tjob = block_job_create("job0", &test_job_driver, NULL, src, 793 0, BLK_PERM_ALL, 794 0, 0, NULL, NULL, &error_abort); 795 tjob->bs = src; 796 job = &tjob->common; 797 block_job_add_bdrv(job, "target", target, 0, BLK_PERM_ALL, &error_abort); 798 799 switch (result) { 800 case TEST_JOB_SUCCESS: 801 break; 802 case TEST_JOB_FAIL_RUN: 803 tjob->run_ret = -EIO; 804 break; 805 case TEST_JOB_FAIL_PREPARE: 806 tjob->prepare_ret = -EIO; 807 break; 808 } 809 aio_context_release(ctx); 810 811 job_start(&job->job); 812 813 if (use_iothread) { 814 /* job_co_entry() is run in the I/O thread, wait for the actual job 815 * code to start (we don't want to catch the job in the pause point in 816 * job_co_entry(). */ 817 while (!tjob->running) { 818 aio_poll(qemu_get_aio_context(), false); 819 } 820 } 821 822 WITH_JOB_LOCK_GUARD() { 823 g_assert_cmpint(job->job.pause_count, ==, 0); 824 g_assert_false(job->job.paused); 825 g_assert_true(tjob->running); 826 g_assert_true(job->job.busy); /* We're in qemu_co_sleep_ns() */ 827 } 828 829 do_drain_begin_unlocked(drain_type, drain_bs); 830 831 WITH_JOB_LOCK_GUARD() { 832 if (drain_type == BDRV_DRAIN_ALL) { 833 /* bdrv_drain_all() drains both src and target */ 834 g_assert_cmpint(job->job.pause_count, ==, 2); 835 } else { 836 g_assert_cmpint(job->job.pause_count, ==, 1); 837 } 838 g_assert_true(job->job.paused); 839 g_assert_false(job->job.busy); /* The job is paused */ 840 } 841 842 do_drain_end_unlocked(drain_type, drain_bs); 843 844 if (use_iothread) { 845 /* 846 * Here we are waiting for the paused status to change, 847 * so don't bother protecting the read every time. 848 * 849 * paused is reset in the I/O thread, wait for it 850 */ 851 while (job->job.paused) { 852 aio_poll(qemu_get_aio_context(), false); 853 } 854 } 855 856 WITH_JOB_LOCK_GUARD() { 857 g_assert_cmpint(job->job.pause_count, ==, 0); 858 g_assert_false(job->job.paused); 859 g_assert_true(job->job.busy); /* We're in qemu_co_sleep_ns() */ 860 } 861 862 do_drain_begin_unlocked(drain_type, target); 863 864 WITH_JOB_LOCK_GUARD() { 865 if (drain_type == BDRV_DRAIN_ALL) { 866 /* bdrv_drain_all() drains both src and target */ 867 g_assert_cmpint(job->job.pause_count, ==, 2); 868 } else { 869 g_assert_cmpint(job->job.pause_count, ==, 1); 870 } 871 g_assert_true(job->job.paused); 872 g_assert_false(job->job.busy); /* The job is paused */ 873 } 874 875 do_drain_end_unlocked(drain_type, target); 876 877 if (use_iothread) { 878 /* 879 * Here we are waiting for the paused status to change, 880 * so don't bother protecting the read every time. 881 * 882 * paused is reset in the I/O thread, wait for it 883 */ 884 while (job->job.paused) { 885 aio_poll(qemu_get_aio_context(), false); 886 } 887 } 888 889 WITH_JOB_LOCK_GUARD() { 890 g_assert_cmpint(job->job.pause_count, ==, 0); 891 g_assert_false(job->job.paused); 892 g_assert_true(job->job.busy); /* We're in qemu_co_sleep_ns() */ 893 } 894 895 WITH_JOB_LOCK_GUARD() { 896 ret = job_complete_sync_locked(&job->job, &error_abort); 897 } 898 g_assert_cmpint(ret, ==, (result == TEST_JOB_SUCCESS ? 0 : -EIO)); 899 900 aio_context_acquire(ctx); 901 if (use_iothread) { 902 blk_set_aio_context(blk_src, qemu_get_aio_context(), &error_abort); 903 assert(blk_get_aio_context(blk_target) == qemu_get_aio_context()); 904 } 905 aio_context_release(ctx); 906 907 blk_unref(blk_src); 908 blk_unref(blk_target); 909 bdrv_unref(src_overlay); 910 bdrv_unref(target); 911 912 if (iothread) { 913 iothread_join(iothread); 914 } 915 } 916 917 static void test_blockjob_common(enum drain_type drain_type, bool use_iothread, 918 enum test_job_result result) 919 { 920 test_blockjob_common_drain_node(drain_type, use_iothread, result, 921 TEST_JOB_DRAIN_SRC); 922 test_blockjob_common_drain_node(drain_type, use_iothread, result, 923 TEST_JOB_DRAIN_SRC_CHILD); 924 } 925 926 static void test_blockjob_drain_all(void) 927 { 928 test_blockjob_common(BDRV_DRAIN_ALL, false, TEST_JOB_SUCCESS); 929 } 930 931 static void test_blockjob_drain(void) 932 { 933 test_blockjob_common(BDRV_DRAIN, false, TEST_JOB_SUCCESS); 934 } 935 936 static void test_blockjob_error_drain_all(void) 937 { 938 test_blockjob_common(BDRV_DRAIN_ALL, false, TEST_JOB_FAIL_RUN); 939 test_blockjob_common(BDRV_DRAIN_ALL, false, TEST_JOB_FAIL_PREPARE); 940 } 941 942 static void test_blockjob_error_drain(void) 943 { 944 test_blockjob_common(BDRV_DRAIN, false, TEST_JOB_FAIL_RUN); 945 test_blockjob_common(BDRV_DRAIN, false, TEST_JOB_FAIL_PREPARE); 946 } 947 948 static void test_blockjob_iothread_drain_all(void) 949 { 950 test_blockjob_common(BDRV_DRAIN_ALL, true, TEST_JOB_SUCCESS); 951 } 952 953 static void test_blockjob_iothread_drain(void) 954 { 955 test_blockjob_common(BDRV_DRAIN, true, TEST_JOB_SUCCESS); 956 } 957 958 static void test_blockjob_iothread_error_drain_all(void) 959 { 960 test_blockjob_common(BDRV_DRAIN_ALL, true, TEST_JOB_FAIL_RUN); 961 test_blockjob_common(BDRV_DRAIN_ALL, true, TEST_JOB_FAIL_PREPARE); 962 } 963 964 static void test_blockjob_iothread_error_drain(void) 965 { 966 test_blockjob_common(BDRV_DRAIN, true, TEST_JOB_FAIL_RUN); 967 test_blockjob_common(BDRV_DRAIN, true, TEST_JOB_FAIL_PREPARE); 968 } 969 970 971 typedef struct BDRVTestTopState { 972 BdrvChild *wait_child; 973 } BDRVTestTopState; 974 975 static void bdrv_test_top_close(BlockDriverState *bs) 976 { 977 BdrvChild *c, *next_c; 978 979 bdrv_graph_wrlock(NULL); 980 QLIST_FOREACH_SAFE(c, &bs->children, next, next_c) { 981 bdrv_unref_child(bs, c); 982 } 983 bdrv_graph_wrunlock(); 984 } 985 986 static int coroutine_fn GRAPH_RDLOCK 987 bdrv_test_top_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes, 988 QEMUIOVector *qiov, BdrvRequestFlags flags) 989 { 990 BDRVTestTopState *tts = bs->opaque; 991 return bdrv_co_preadv(tts->wait_child, offset, bytes, qiov, flags); 992 } 993 994 static BlockDriver bdrv_test_top_driver = { 995 .format_name = "test_top_driver", 996 .instance_size = sizeof(BDRVTestTopState), 997 998 .bdrv_close = bdrv_test_top_close, 999 .bdrv_co_preadv = bdrv_test_top_co_preadv, 1000 1001 .bdrv_child_perm = bdrv_default_perms, 1002 }; 1003 1004 typedef struct TestCoDeleteByDrainData { 1005 BlockBackend *blk; 1006 bool detach_instead_of_delete; 1007 bool done; 1008 } TestCoDeleteByDrainData; 1009 1010 static void coroutine_fn test_co_delete_by_drain(void *opaque) 1011 { 1012 TestCoDeleteByDrainData *dbdd = opaque; 1013 BlockBackend *blk = dbdd->blk; 1014 BlockDriverState *bs = blk_bs(blk); 1015 BDRVTestTopState *tts = bs->opaque; 1016 void *buffer = g_malloc(65536); 1017 QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buffer, 65536); 1018 1019 /* Pretend some internal write operation from parent to child. 1020 * Important: We have to read from the child, not from the parent! 1021 * Draining works by first propagating it all up the tree to the 1022 * root and then waiting for drainage from root to the leaves 1023 * (protocol nodes). If we have a request waiting on the root, 1024 * everything will be drained before we go back down the tree, but 1025 * we do not want that. We want to be in the middle of draining 1026 * when this following requests returns. */ 1027 bdrv_graph_co_rdlock(); 1028 bdrv_co_preadv(tts->wait_child, 0, 65536, &qiov, 0); 1029 bdrv_graph_co_rdunlock(); 1030 1031 g_assert_cmpint(bs->refcnt, ==, 1); 1032 1033 if (!dbdd->detach_instead_of_delete) { 1034 blk_co_unref(blk); 1035 } else { 1036 BdrvChild *c, *next_c; 1037 bdrv_graph_co_rdlock(); 1038 QLIST_FOREACH_SAFE(c, &bs->children, next, next_c) { 1039 bdrv_graph_co_rdunlock(); 1040 bdrv_co_unref_child(bs, c); 1041 bdrv_graph_co_rdlock(); 1042 } 1043 bdrv_graph_co_rdunlock(); 1044 } 1045 1046 dbdd->done = true; 1047 g_free(buffer); 1048 } 1049 1050 /** 1051 * Test what happens when some BDS has some children, you drain one of 1052 * them and this results in the BDS being deleted. 1053 * 1054 * If @detach_instead_of_delete is set, the BDS is not going to be 1055 * deleted but will only detach all of its children. 1056 */ 1057 static void do_test_delete_by_drain(bool detach_instead_of_delete, 1058 enum drain_type drain_type) 1059 { 1060 BlockBackend *blk; 1061 BlockDriverState *bs, *child_bs, *null_bs; 1062 BDRVTestTopState *tts; 1063 TestCoDeleteByDrainData dbdd; 1064 Coroutine *co; 1065 1066 bs = bdrv_new_open_driver(&bdrv_test_top_driver, "top", BDRV_O_RDWR, 1067 &error_abort); 1068 bs->total_sectors = 65536 >> BDRV_SECTOR_BITS; 1069 tts = bs->opaque; 1070 1071 null_bs = bdrv_open("null-co://", NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL, 1072 &error_abort); 1073 bdrv_graph_wrlock(NULL); 1074 bdrv_attach_child(bs, null_bs, "null-child", &child_of_bds, 1075 BDRV_CHILD_DATA, &error_abort); 1076 bdrv_graph_wrunlock(); 1077 1078 /* This child will be the one to pass to requests through to, and 1079 * it will stall until a drain occurs */ 1080 child_bs = bdrv_new_open_driver(&bdrv_test, "child", BDRV_O_RDWR, 1081 &error_abort); 1082 child_bs->total_sectors = 65536 >> BDRV_SECTOR_BITS; 1083 /* Takes our reference to child_bs */ 1084 bdrv_graph_wrlock(NULL); 1085 tts->wait_child = bdrv_attach_child(bs, child_bs, "wait-child", 1086 &child_of_bds, 1087 BDRV_CHILD_DATA | BDRV_CHILD_PRIMARY, 1088 &error_abort); 1089 bdrv_graph_wrunlock(); 1090 1091 /* This child is just there to be deleted 1092 * (for detach_instead_of_delete == true) */ 1093 null_bs = bdrv_open("null-co://", NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL, 1094 &error_abort); 1095 bdrv_graph_wrlock(NULL); 1096 bdrv_attach_child(bs, null_bs, "null-child", &child_of_bds, BDRV_CHILD_DATA, 1097 &error_abort); 1098 bdrv_graph_wrunlock(); 1099 1100 blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL); 1101 blk_insert_bs(blk, bs, &error_abort); 1102 1103 /* Referenced by blk now */ 1104 bdrv_unref(bs); 1105 1106 g_assert_cmpint(bs->refcnt, ==, 1); 1107 g_assert_cmpint(child_bs->refcnt, ==, 1); 1108 g_assert_cmpint(null_bs->refcnt, ==, 1); 1109 1110 1111 dbdd = (TestCoDeleteByDrainData){ 1112 .blk = blk, 1113 .detach_instead_of_delete = detach_instead_of_delete, 1114 .done = false, 1115 }; 1116 co = qemu_coroutine_create(test_co_delete_by_drain, &dbdd); 1117 qemu_coroutine_enter(co); 1118 1119 /* Drain the child while the read operation is still pending. 1120 * This should result in the operation finishing and 1121 * test_co_delete_by_drain() resuming. Thus, @bs will be deleted 1122 * and the coroutine will exit while this drain operation is still 1123 * in progress. */ 1124 switch (drain_type) { 1125 case BDRV_DRAIN: 1126 bdrv_ref(child_bs); 1127 bdrv_drain(child_bs); 1128 bdrv_unref(child_bs); 1129 break; 1130 case BDRV_DRAIN_ALL: 1131 bdrv_drain_all_begin(); 1132 bdrv_drain_all_end(); 1133 break; 1134 default: 1135 g_assert_not_reached(); 1136 } 1137 1138 while (!dbdd.done) { 1139 aio_poll(qemu_get_aio_context(), true); 1140 } 1141 1142 if (detach_instead_of_delete) { 1143 /* Here, the reference has not passed over to the coroutine, 1144 * so we have to delete the BB ourselves */ 1145 blk_unref(blk); 1146 } 1147 } 1148 1149 static void test_delete_by_drain(void) 1150 { 1151 do_test_delete_by_drain(false, BDRV_DRAIN); 1152 } 1153 1154 static void test_detach_by_drain_all(void) 1155 { 1156 do_test_delete_by_drain(true, BDRV_DRAIN_ALL); 1157 } 1158 1159 static void test_detach_by_drain(void) 1160 { 1161 do_test_delete_by_drain(true, BDRV_DRAIN); 1162 } 1163 1164 1165 struct detach_by_parent_data { 1166 BlockDriverState *parent_b; 1167 BdrvChild *child_b; 1168 BlockDriverState *c; 1169 BdrvChild *child_c; 1170 bool by_parent_cb; 1171 bool detach_on_drain; 1172 }; 1173 static struct detach_by_parent_data detach_by_parent_data; 1174 1175 static void no_coroutine_fn detach_indirect_bh(void *opaque) 1176 { 1177 struct detach_by_parent_data *data = opaque; 1178 1179 bdrv_dec_in_flight(data->child_b->bs); 1180 1181 bdrv_graph_wrlock(NULL); 1182 bdrv_unref_child(data->parent_b, data->child_b); 1183 1184 bdrv_ref(data->c); 1185 data->child_c = bdrv_attach_child(data->parent_b, data->c, "PB-C", 1186 &child_of_bds, BDRV_CHILD_DATA, 1187 &error_abort); 1188 bdrv_graph_wrunlock(); 1189 } 1190 1191 static void coroutine_mixed_fn detach_by_parent_aio_cb(void *opaque, int ret) 1192 { 1193 struct detach_by_parent_data *data = &detach_by_parent_data; 1194 1195 g_assert_cmpint(ret, ==, 0); 1196 if (data->by_parent_cb) { 1197 bdrv_inc_in_flight(data->child_b->bs); 1198 aio_bh_schedule_oneshot(qemu_get_current_aio_context(), 1199 detach_indirect_bh, &detach_by_parent_data); 1200 } 1201 } 1202 1203 static void GRAPH_RDLOCK detach_by_driver_cb_drained_begin(BdrvChild *child) 1204 { 1205 struct detach_by_parent_data *data = &detach_by_parent_data; 1206 1207 if (!data->detach_on_drain) { 1208 return; 1209 } 1210 data->detach_on_drain = false; 1211 1212 bdrv_inc_in_flight(data->child_b->bs); 1213 aio_bh_schedule_oneshot(qemu_get_current_aio_context(), 1214 detach_indirect_bh, &detach_by_parent_data); 1215 child_of_bds.drained_begin(child); 1216 } 1217 1218 static BdrvChildClass detach_by_driver_cb_class; 1219 1220 /* 1221 * Initial graph: 1222 * 1223 * PA PB 1224 * \ / \ 1225 * A B C 1226 * 1227 * by_parent_cb == true: Test that parent callbacks don't poll 1228 * 1229 * PA has a pending write request whose callback changes the child nodes of 1230 * PB: It removes B and adds C instead. The subtree of PB is drained, which 1231 * will indirectly drain the write request, too. 1232 * 1233 * by_parent_cb == false: Test that bdrv_drain_invoke() doesn't poll 1234 * 1235 * PA's BdrvChildClass has a .drained_begin callback that schedules a BH 1236 * that does the same graph change. If bdrv_drain_invoke() calls it, the 1237 * state is messed up, but if it is only polled in the single 1238 * BDRV_POLL_WHILE() at the end of the drain, this should work fine. 1239 */ 1240 static void TSA_NO_TSA test_detach_indirect(bool by_parent_cb) 1241 { 1242 BlockBackend *blk; 1243 BlockDriverState *parent_a, *parent_b, *a, *b, *c; 1244 BdrvChild *child_a, *child_b; 1245 BlockAIOCB *acb; 1246 1247 QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, NULL, 0); 1248 1249 if (!by_parent_cb) { 1250 detach_by_driver_cb_class = child_of_bds; 1251 detach_by_driver_cb_class.drained_begin = 1252 detach_by_driver_cb_drained_begin; 1253 detach_by_driver_cb_class.drained_end = NULL; 1254 detach_by_driver_cb_class.drained_poll = NULL; 1255 } 1256 1257 detach_by_parent_data = (struct detach_by_parent_data) { 1258 .detach_on_drain = false, 1259 }; 1260 1261 /* Create all involved nodes */ 1262 parent_a = bdrv_new_open_driver(&bdrv_test, "parent-a", BDRV_O_RDWR, 1263 &error_abort); 1264 parent_b = bdrv_new_open_driver(&bdrv_test, "parent-b", 0, 1265 &error_abort); 1266 1267 a = bdrv_new_open_driver(&bdrv_test, "a", BDRV_O_RDWR, &error_abort); 1268 b = bdrv_new_open_driver(&bdrv_test, "b", BDRV_O_RDWR, &error_abort); 1269 c = bdrv_new_open_driver(&bdrv_test, "c", BDRV_O_RDWR, &error_abort); 1270 1271 /* blk is a BB for parent-a */ 1272 blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL); 1273 blk_insert_bs(blk, parent_a, &error_abort); 1274 bdrv_unref(parent_a); 1275 1276 /* If we want to get bdrv_drain_invoke() to call aio_poll(), the driver 1277 * callback must not return immediately. */ 1278 if (!by_parent_cb) { 1279 BDRVTestState *s = parent_a->opaque; 1280 s->sleep_in_drain_begin = true; 1281 } 1282 1283 /* Set child relationships */ 1284 bdrv_ref(b); 1285 bdrv_ref(a); 1286 bdrv_graph_wrlock(NULL); 1287 child_b = bdrv_attach_child(parent_b, b, "PB-B", &child_of_bds, 1288 BDRV_CHILD_DATA, &error_abort); 1289 child_a = bdrv_attach_child(parent_b, a, "PB-A", &child_of_bds, 1290 BDRV_CHILD_COW, &error_abort); 1291 1292 bdrv_ref(a); 1293 bdrv_attach_child(parent_a, a, "PA-A", 1294 by_parent_cb ? &child_of_bds : &detach_by_driver_cb_class, 1295 BDRV_CHILD_DATA, &error_abort); 1296 bdrv_graph_wrunlock(); 1297 1298 g_assert_cmpint(parent_a->refcnt, ==, 1); 1299 g_assert_cmpint(parent_b->refcnt, ==, 1); 1300 g_assert_cmpint(a->refcnt, ==, 3); 1301 g_assert_cmpint(b->refcnt, ==, 2); 1302 g_assert_cmpint(c->refcnt, ==, 1); 1303 1304 g_assert(QLIST_FIRST(&parent_b->children) == child_a); 1305 g_assert(QLIST_NEXT(child_a, next) == child_b); 1306 g_assert(QLIST_NEXT(child_b, next) == NULL); 1307 1308 /* Start the evil write request */ 1309 detach_by_parent_data = (struct detach_by_parent_data) { 1310 .parent_b = parent_b, 1311 .child_b = child_b, 1312 .c = c, 1313 .by_parent_cb = by_parent_cb, 1314 .detach_on_drain = true, 1315 }; 1316 acb = blk_aio_preadv(blk, 0, &qiov, 0, detach_by_parent_aio_cb, NULL); 1317 g_assert(acb != NULL); 1318 1319 /* Drain and check the expected result */ 1320 bdrv_drained_begin(parent_b); 1321 bdrv_drained_begin(a); 1322 bdrv_drained_begin(b); 1323 bdrv_drained_begin(c); 1324 1325 g_assert(detach_by_parent_data.child_c != NULL); 1326 1327 g_assert_cmpint(parent_a->refcnt, ==, 1); 1328 g_assert_cmpint(parent_b->refcnt, ==, 1); 1329 g_assert_cmpint(a->refcnt, ==, 3); 1330 g_assert_cmpint(b->refcnt, ==, 1); 1331 g_assert_cmpint(c->refcnt, ==, 2); 1332 1333 g_assert(QLIST_FIRST(&parent_b->children) == detach_by_parent_data.child_c); 1334 g_assert(QLIST_NEXT(detach_by_parent_data.child_c, next) == child_a); 1335 g_assert(QLIST_NEXT(child_a, next) == NULL); 1336 1337 g_assert_cmpint(parent_a->quiesce_counter, ==, 1); 1338 g_assert_cmpint(parent_b->quiesce_counter, ==, 3); 1339 g_assert_cmpint(a->quiesce_counter, ==, 1); 1340 g_assert_cmpint(b->quiesce_counter, ==, 1); 1341 g_assert_cmpint(c->quiesce_counter, ==, 1); 1342 1343 bdrv_drained_end(parent_b); 1344 bdrv_drained_end(a); 1345 bdrv_drained_end(b); 1346 bdrv_drained_end(c); 1347 1348 bdrv_unref(parent_b); 1349 blk_unref(blk); 1350 1351 g_assert_cmpint(a->refcnt, ==, 1); 1352 g_assert_cmpint(b->refcnt, ==, 1); 1353 g_assert_cmpint(c->refcnt, ==, 1); 1354 bdrv_unref(a); 1355 bdrv_unref(b); 1356 bdrv_unref(c); 1357 } 1358 1359 static void test_detach_by_parent_cb(void) 1360 { 1361 test_detach_indirect(true); 1362 } 1363 1364 static void test_detach_by_driver_cb(void) 1365 { 1366 test_detach_indirect(false); 1367 } 1368 1369 static void test_append_to_drained(void) 1370 { 1371 BlockBackend *blk; 1372 BlockDriverState *base, *overlay; 1373 BDRVTestState *base_s, *overlay_s; 1374 1375 blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL); 1376 base = bdrv_new_open_driver(&bdrv_test, "base", BDRV_O_RDWR, &error_abort); 1377 base_s = base->opaque; 1378 blk_insert_bs(blk, base, &error_abort); 1379 1380 overlay = bdrv_new_open_driver(&bdrv_test, "overlay", BDRV_O_RDWR, 1381 &error_abort); 1382 overlay_s = overlay->opaque; 1383 1384 do_drain_begin(BDRV_DRAIN, base); 1385 g_assert_cmpint(base->quiesce_counter, ==, 1); 1386 g_assert_cmpint(base_s->drain_count, ==, 1); 1387 g_assert_cmpint(base->in_flight, ==, 0); 1388 1389 aio_context_acquire(qemu_get_aio_context()); 1390 bdrv_append(overlay, base, &error_abort); 1391 aio_context_release(qemu_get_aio_context()); 1392 1393 g_assert_cmpint(base->in_flight, ==, 0); 1394 g_assert_cmpint(overlay->in_flight, ==, 0); 1395 1396 g_assert_cmpint(base->quiesce_counter, ==, 1); 1397 g_assert_cmpint(base_s->drain_count, ==, 1); 1398 g_assert_cmpint(overlay->quiesce_counter, ==, 1); 1399 g_assert_cmpint(overlay_s->drain_count, ==, 1); 1400 1401 do_drain_end(BDRV_DRAIN, base); 1402 1403 g_assert_cmpint(base->quiesce_counter, ==, 0); 1404 g_assert_cmpint(base_s->drain_count, ==, 0); 1405 g_assert_cmpint(overlay->quiesce_counter, ==, 0); 1406 g_assert_cmpint(overlay_s->drain_count, ==, 0); 1407 1408 bdrv_unref(overlay); 1409 bdrv_unref(base); 1410 blk_unref(blk); 1411 } 1412 1413 static void test_set_aio_context(void) 1414 { 1415 BlockDriverState *bs; 1416 IOThread *a = iothread_new(); 1417 IOThread *b = iothread_new(); 1418 AioContext *ctx_a = iothread_get_aio_context(a); 1419 AioContext *ctx_b = iothread_get_aio_context(b); 1420 1421 bs = bdrv_new_open_driver(&bdrv_test, "test-node", BDRV_O_RDWR, 1422 &error_abort); 1423 1424 bdrv_drained_begin(bs); 1425 bdrv_try_change_aio_context(bs, ctx_a, NULL, &error_abort); 1426 1427 aio_context_acquire(ctx_a); 1428 bdrv_drained_end(bs); 1429 1430 bdrv_drained_begin(bs); 1431 bdrv_try_change_aio_context(bs, ctx_b, NULL, &error_abort); 1432 aio_context_release(ctx_a); 1433 aio_context_acquire(ctx_b); 1434 bdrv_try_change_aio_context(bs, qemu_get_aio_context(), NULL, &error_abort); 1435 aio_context_release(ctx_b); 1436 bdrv_drained_end(bs); 1437 1438 bdrv_unref(bs); 1439 iothread_join(a); 1440 iothread_join(b); 1441 } 1442 1443 1444 typedef struct TestDropBackingBlockJob { 1445 BlockJob common; 1446 bool should_complete; 1447 bool *did_complete; 1448 BlockDriverState *detach_also; 1449 BlockDriverState *bs; 1450 } TestDropBackingBlockJob; 1451 1452 static int coroutine_fn test_drop_backing_job_run(Job *job, Error **errp) 1453 { 1454 TestDropBackingBlockJob *s = 1455 container_of(job, TestDropBackingBlockJob, common.job); 1456 1457 while (!s->should_complete) { 1458 job_sleep_ns(job, 0); 1459 } 1460 1461 return 0; 1462 } 1463 1464 static void test_drop_backing_job_commit(Job *job) 1465 { 1466 TestDropBackingBlockJob *s = 1467 container_of(job, TestDropBackingBlockJob, common.job); 1468 1469 bdrv_set_backing_hd(s->bs, NULL, &error_abort); 1470 bdrv_set_backing_hd(s->detach_also, NULL, &error_abort); 1471 1472 *s->did_complete = true; 1473 } 1474 1475 static const BlockJobDriver test_drop_backing_job_driver = { 1476 .job_driver = { 1477 .instance_size = sizeof(TestDropBackingBlockJob), 1478 .free = block_job_free, 1479 .user_resume = block_job_user_resume, 1480 .run = test_drop_backing_job_run, 1481 .commit = test_drop_backing_job_commit, 1482 } 1483 }; 1484 1485 /** 1486 * Creates a child node with three parent nodes on it, and then runs a 1487 * block job on the final one, parent-node-2. 1488 * 1489 * The job is then asked to complete before a section where the child 1490 * is drained. 1491 * 1492 * Ending this section will undrain the child's parents, first 1493 * parent-node-2, then parent-node-1, then parent-node-0 -- the parent 1494 * list is in reverse order of how they were added. Ending the drain 1495 * on parent-node-2 will resume the job, thus completing it and 1496 * scheduling job_exit(). 1497 * 1498 * Ending the drain on parent-node-1 will poll the AioContext, which 1499 * lets job_exit() and thus test_drop_backing_job_commit() run. That 1500 * function first removes the child as parent-node-2's backing file. 1501 * 1502 * In old (and buggy) implementations, there are two problems with 1503 * that: 1504 * (A) bdrv_drain_invoke() polls for every node that leaves the 1505 * drained section. This means that job_exit() is scheduled 1506 * before the child has left the drained section. Its 1507 * quiesce_counter is therefore still 1 when it is removed from 1508 * parent-node-2. 1509 * 1510 * (B) bdrv_replace_child_noperm() calls drained_end() on the old 1511 * child's parents as many times as the child is quiesced. This 1512 * means it will call drained_end() on parent-node-2 once. 1513 * Because parent-node-2 is no longer quiesced at this point, this 1514 * will fail. 1515 * 1516 * bdrv_replace_child_noperm() therefore must call drained_end() on 1517 * the parent only if it really is still drained because the child is 1518 * drained. 1519 * 1520 * If removing child from parent-node-2 was successful (as it should 1521 * be), test_drop_backing_job_commit() will then also remove the child 1522 * from parent-node-0. 1523 * 1524 * With an old version of our drain infrastructure ((A) above), that 1525 * resulted in the following flow: 1526 * 1527 * 1. child attempts to leave its drained section. The call recurses 1528 * to its parents. 1529 * 1530 * 2. parent-node-2 leaves the drained section. Polling in 1531 * bdrv_drain_invoke() will schedule job_exit(). 1532 * 1533 * 3. parent-node-1 leaves the drained section. Polling in 1534 * bdrv_drain_invoke() will run job_exit(), thus disconnecting 1535 * parent-node-0 from the child node. 1536 * 1537 * 4. bdrv_parent_drained_end() uses a QLIST_FOREACH_SAFE() loop to 1538 * iterate over the parents. Thus, it now accesses the BdrvChild 1539 * object that used to connect parent-node-0 and the child node. 1540 * However, that object no longer exists, so it accesses a dangling 1541 * pointer. 1542 * 1543 * The solution is to only poll once when running a bdrv_drained_end() 1544 * operation, specifically at the end when all drained_end() 1545 * operations for all involved nodes have been scheduled. 1546 * Note that this also solves (A) above, thus hiding (B). 1547 */ 1548 static void test_blockjob_commit_by_drained_end(void) 1549 { 1550 BlockDriverState *bs_child, *bs_parents[3]; 1551 TestDropBackingBlockJob *job; 1552 bool job_has_completed = false; 1553 int i; 1554 1555 bs_child = bdrv_new_open_driver(&bdrv_test, "child-node", BDRV_O_RDWR, 1556 &error_abort); 1557 1558 for (i = 0; i < 3; i++) { 1559 char name[32]; 1560 snprintf(name, sizeof(name), "parent-node-%i", i); 1561 bs_parents[i] = bdrv_new_open_driver(&bdrv_test, name, BDRV_O_RDWR, 1562 &error_abort); 1563 bdrv_set_backing_hd(bs_parents[i], bs_child, &error_abort); 1564 } 1565 1566 job = block_job_create("job", &test_drop_backing_job_driver, NULL, 1567 bs_parents[2], 0, BLK_PERM_ALL, 0, 0, NULL, NULL, 1568 &error_abort); 1569 job->bs = bs_parents[2]; 1570 1571 job->detach_also = bs_parents[0]; 1572 job->did_complete = &job_has_completed; 1573 1574 job_start(&job->common.job); 1575 1576 job->should_complete = true; 1577 bdrv_drained_begin(bs_child); 1578 g_assert(!job_has_completed); 1579 bdrv_drained_end(bs_child); 1580 aio_poll(qemu_get_aio_context(), false); 1581 g_assert(job_has_completed); 1582 1583 bdrv_unref(bs_parents[0]); 1584 bdrv_unref(bs_parents[1]); 1585 bdrv_unref(bs_parents[2]); 1586 bdrv_unref(bs_child); 1587 } 1588 1589 1590 typedef struct TestSimpleBlockJob { 1591 BlockJob common; 1592 bool should_complete; 1593 bool *did_complete; 1594 } TestSimpleBlockJob; 1595 1596 static int coroutine_fn test_simple_job_run(Job *job, Error **errp) 1597 { 1598 TestSimpleBlockJob *s = container_of(job, TestSimpleBlockJob, common.job); 1599 1600 while (!s->should_complete) { 1601 job_sleep_ns(job, 0); 1602 } 1603 1604 return 0; 1605 } 1606 1607 static void test_simple_job_clean(Job *job) 1608 { 1609 TestSimpleBlockJob *s = container_of(job, TestSimpleBlockJob, common.job); 1610 *s->did_complete = true; 1611 } 1612 1613 static const BlockJobDriver test_simple_job_driver = { 1614 .job_driver = { 1615 .instance_size = sizeof(TestSimpleBlockJob), 1616 .free = block_job_free, 1617 .user_resume = block_job_user_resume, 1618 .run = test_simple_job_run, 1619 .clean = test_simple_job_clean, 1620 }, 1621 }; 1622 1623 static int drop_intermediate_poll_update_filename(BdrvChild *child, 1624 BlockDriverState *new_base, 1625 const char *filename, 1626 Error **errp) 1627 { 1628 /* 1629 * We are free to poll here, which may change the block graph, if 1630 * it is not drained. 1631 */ 1632 1633 /* If the job is not drained: Complete it, schedule job_exit() */ 1634 aio_poll(qemu_get_current_aio_context(), false); 1635 /* If the job is not drained: Run job_exit(), finish the job */ 1636 aio_poll(qemu_get_current_aio_context(), false); 1637 1638 return 0; 1639 } 1640 1641 /** 1642 * Test a poll in the midst of bdrv_drop_intermediate(). 1643 * 1644 * bdrv_drop_intermediate() calls BdrvChildClass.update_filename(), 1645 * which can yield or poll. This may lead to graph changes, unless 1646 * the whole subtree in question is drained. 1647 * 1648 * We test this on the following graph: 1649 * 1650 * Job 1651 * 1652 * | 1653 * job-node 1654 * | 1655 * v 1656 * 1657 * job-node 1658 * 1659 * | 1660 * backing 1661 * | 1662 * v 1663 * 1664 * node-2 --chain--> node-1 --chain--> node-0 1665 * 1666 * We drop node-1 with bdrv_drop_intermediate(top=node-1, base=node-0). 1667 * 1668 * This first updates node-2's backing filename by invoking 1669 * drop_intermediate_poll_update_filename(), which polls twice. This 1670 * causes the job to finish, which in turns causes the job-node to be 1671 * deleted. 1672 * 1673 * bdrv_drop_intermediate() uses a QLIST_FOREACH_SAFE() loop, so it 1674 * already has a pointer to the BdrvChild edge between job-node and 1675 * node-1. When it tries to handle that edge, we probably get a 1676 * segmentation fault because the object no longer exists. 1677 * 1678 * 1679 * The solution is for bdrv_drop_intermediate() to drain top's 1680 * subtree. This prevents graph changes from happening just because 1681 * BdrvChildClass.update_filename() yields or polls. Thus, the block 1682 * job is paused during that drained section and must finish before or 1683 * after. 1684 * 1685 * (In addition, bdrv_replace_child() must keep the job paused.) 1686 */ 1687 static void test_drop_intermediate_poll(void) 1688 { 1689 static BdrvChildClass chain_child_class; 1690 BlockDriverState *chain[3]; 1691 TestSimpleBlockJob *job; 1692 BlockDriverState *job_node; 1693 bool job_has_completed = false; 1694 int i; 1695 int ret; 1696 1697 chain_child_class = child_of_bds; 1698 chain_child_class.update_filename = drop_intermediate_poll_update_filename; 1699 1700 for (i = 0; i < 3; i++) { 1701 char name[32]; 1702 snprintf(name, 32, "node-%i", i); 1703 1704 chain[i] = bdrv_new_open_driver(&bdrv_test, name, 0, &error_abort); 1705 } 1706 1707 job_node = bdrv_new_open_driver(&bdrv_test, "job-node", BDRV_O_RDWR, 1708 &error_abort); 1709 bdrv_set_backing_hd(job_node, chain[1], &error_abort); 1710 1711 /* 1712 * Establish the chain last, so the chain links are the first 1713 * elements in the BDS.parents lists 1714 */ 1715 bdrv_graph_wrlock(NULL); 1716 for (i = 0; i < 3; i++) { 1717 if (i) { 1718 /* Takes the reference to chain[i - 1] */ 1719 bdrv_attach_child(chain[i], chain[i - 1], "chain", 1720 &chain_child_class, BDRV_CHILD_COW, &error_abort); 1721 } 1722 } 1723 bdrv_graph_wrunlock(); 1724 1725 job = block_job_create("job", &test_simple_job_driver, NULL, job_node, 1726 0, BLK_PERM_ALL, 0, 0, NULL, NULL, &error_abort); 1727 1728 /* The job has a reference now */ 1729 bdrv_unref(job_node); 1730 1731 job->did_complete = &job_has_completed; 1732 1733 job_start(&job->common.job); 1734 job->should_complete = true; 1735 1736 g_assert(!job_has_completed); 1737 ret = bdrv_drop_intermediate(chain[1], chain[0], NULL); 1738 aio_poll(qemu_get_aio_context(), false); 1739 g_assert(ret == 0); 1740 g_assert(job_has_completed); 1741 1742 bdrv_unref(chain[2]); 1743 } 1744 1745 1746 typedef struct BDRVReplaceTestState { 1747 bool setup_completed; 1748 bool was_drained; 1749 bool was_undrained; 1750 bool has_read; 1751 1752 int drain_count; 1753 1754 bool yield_before_read; 1755 Coroutine *io_co; 1756 Coroutine *drain_co; 1757 } BDRVReplaceTestState; 1758 1759 static void bdrv_replace_test_close(BlockDriverState *bs) 1760 { 1761 } 1762 1763 /** 1764 * If @bs has a backing file: 1765 * Yield if .yield_before_read is true (and wait for drain_begin to 1766 * wake us up). 1767 * Forward the read to bs->backing. Set .has_read to true. 1768 * If drain_begin has woken us, wake it in turn. 1769 * 1770 * Otherwise: 1771 * Set .has_read to true and return success. 1772 */ 1773 static int coroutine_fn GRAPH_RDLOCK 1774 bdrv_replace_test_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes, 1775 QEMUIOVector *qiov, BdrvRequestFlags flags) 1776 { 1777 BDRVReplaceTestState *s = bs->opaque; 1778 1779 if (bs->backing) { 1780 int ret; 1781 1782 g_assert(!s->drain_count); 1783 1784 s->io_co = qemu_coroutine_self(); 1785 if (s->yield_before_read) { 1786 s->yield_before_read = false; 1787 qemu_coroutine_yield(); 1788 } 1789 s->io_co = NULL; 1790 1791 ret = bdrv_co_preadv(bs->backing, offset, bytes, qiov, 0); 1792 s->has_read = true; 1793 1794 /* Wake up drain_co if it runs */ 1795 if (s->drain_co) { 1796 aio_co_wake(s->drain_co); 1797 } 1798 1799 return ret; 1800 } 1801 1802 s->has_read = true; 1803 return 0; 1804 } 1805 1806 static void coroutine_fn bdrv_replace_test_drain_co(void *opaque) 1807 { 1808 BlockDriverState *bs = opaque; 1809 BDRVReplaceTestState *s = bs->opaque; 1810 1811 /* Keep waking io_co up until it is done */ 1812 while (s->io_co) { 1813 aio_co_wake(s->io_co); 1814 s->io_co = NULL; 1815 qemu_coroutine_yield(); 1816 } 1817 s->drain_co = NULL; 1818 bdrv_dec_in_flight(bs); 1819 } 1820 1821 /** 1822 * If .drain_count is 0, wake up .io_co if there is one; and set 1823 * .was_drained. 1824 * Increment .drain_count. 1825 */ 1826 static void bdrv_replace_test_drain_begin(BlockDriverState *bs) 1827 { 1828 BDRVReplaceTestState *s = bs->opaque; 1829 1830 if (!s->setup_completed) { 1831 return; 1832 } 1833 1834 if (!s->drain_count) { 1835 s->drain_co = qemu_coroutine_create(bdrv_replace_test_drain_co, bs); 1836 bdrv_inc_in_flight(bs); 1837 aio_co_enter(bdrv_get_aio_context(bs), s->drain_co); 1838 s->was_drained = true; 1839 } 1840 s->drain_count++; 1841 } 1842 1843 static void coroutine_fn bdrv_replace_test_read_entry(void *opaque) 1844 { 1845 BlockDriverState *bs = opaque; 1846 char data; 1847 QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, &data, 1); 1848 int ret; 1849 1850 /* Queue a read request post-drain */ 1851 bdrv_graph_co_rdlock(); 1852 ret = bdrv_replace_test_co_preadv(bs, 0, 1, &qiov, 0); 1853 bdrv_graph_co_rdunlock(); 1854 1855 g_assert(ret >= 0); 1856 bdrv_dec_in_flight(bs); 1857 } 1858 1859 /** 1860 * Reduce .drain_count, set .was_undrained once it reaches 0. 1861 * If .drain_count reaches 0 and the node has a backing file, issue a 1862 * read request. 1863 */ 1864 static void bdrv_replace_test_drain_end(BlockDriverState *bs) 1865 { 1866 BDRVReplaceTestState *s = bs->opaque; 1867 1868 if (!s->setup_completed) { 1869 return; 1870 } 1871 1872 g_assert(s->drain_count > 0); 1873 if (!--s->drain_count) { 1874 s->was_undrained = true; 1875 1876 if (bs->backing) { 1877 Coroutine *co = qemu_coroutine_create(bdrv_replace_test_read_entry, 1878 bs); 1879 bdrv_inc_in_flight(bs); 1880 aio_co_enter(bdrv_get_aio_context(bs), co); 1881 } 1882 } 1883 } 1884 1885 static BlockDriver bdrv_replace_test = { 1886 .format_name = "replace_test", 1887 .instance_size = sizeof(BDRVReplaceTestState), 1888 .supports_backing = true, 1889 1890 .bdrv_close = bdrv_replace_test_close, 1891 .bdrv_co_preadv = bdrv_replace_test_co_preadv, 1892 1893 .bdrv_drain_begin = bdrv_replace_test_drain_begin, 1894 .bdrv_drain_end = bdrv_replace_test_drain_end, 1895 1896 .bdrv_child_perm = bdrv_default_perms, 1897 }; 1898 1899 static void coroutine_fn test_replace_child_mid_drain_read_co(void *opaque) 1900 { 1901 int ret; 1902 char data; 1903 1904 ret = blk_co_pread(opaque, 0, 1, &data, 0); 1905 g_assert(ret >= 0); 1906 } 1907 1908 /** 1909 * We test two things: 1910 * (1) bdrv_replace_child_noperm() must not undrain the parent if both 1911 * children are drained. 1912 * (2) bdrv_replace_child_noperm() must never flush I/O requests to a 1913 * drained child. If the old child is drained, it must flush I/O 1914 * requests after the new one has been attached. If the new child 1915 * is drained, it must flush I/O requests before the old one is 1916 * detached. 1917 * 1918 * To do so, we create one parent node and two child nodes; then 1919 * attach one of the children (old_child_bs) to the parent, then 1920 * drain both old_child_bs and new_child_bs according to 1921 * old_drain_count and new_drain_count, respectively, and finally 1922 * we invoke bdrv_replace_node() to replace old_child_bs by 1923 * new_child_bs. 1924 * 1925 * The test block driver we use here (bdrv_replace_test) has a read 1926 * function that: 1927 * - For the parent node, can optionally yield, and then forwards the 1928 * read to bdrv_preadv(), 1929 * - For the child node, just returns immediately. 1930 * 1931 * If the read yields, the drain_begin function will wake it up. 1932 * 1933 * The drain_end function issues a read on the parent once it is fully 1934 * undrained (which simulates requests starting to come in again). 1935 */ 1936 static void do_test_replace_child_mid_drain(int old_drain_count, 1937 int new_drain_count) 1938 { 1939 BlockBackend *parent_blk; 1940 BlockDriverState *parent_bs; 1941 BlockDriverState *old_child_bs, *new_child_bs; 1942 BDRVReplaceTestState *parent_s; 1943 BDRVReplaceTestState *old_child_s, *new_child_s; 1944 Coroutine *io_co; 1945 int i; 1946 1947 parent_bs = bdrv_new_open_driver(&bdrv_replace_test, "parent", 0, 1948 &error_abort); 1949 parent_s = parent_bs->opaque; 1950 1951 parent_blk = blk_new(qemu_get_aio_context(), 1952 BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL); 1953 blk_insert_bs(parent_blk, parent_bs, &error_abort); 1954 1955 old_child_bs = bdrv_new_open_driver(&bdrv_replace_test, "old-child", 0, 1956 &error_abort); 1957 new_child_bs = bdrv_new_open_driver(&bdrv_replace_test, "new-child", 0, 1958 &error_abort); 1959 old_child_s = old_child_bs->opaque; 1960 new_child_s = new_child_bs->opaque; 1961 1962 /* So that we can read something */ 1963 parent_bs->total_sectors = 1; 1964 old_child_bs->total_sectors = 1; 1965 new_child_bs->total_sectors = 1; 1966 1967 bdrv_ref(old_child_bs); 1968 bdrv_graph_wrlock(NULL); 1969 bdrv_attach_child(parent_bs, old_child_bs, "child", &child_of_bds, 1970 BDRV_CHILD_COW, &error_abort); 1971 bdrv_graph_wrunlock(); 1972 parent_s->setup_completed = true; 1973 1974 for (i = 0; i < old_drain_count; i++) { 1975 bdrv_drained_begin(old_child_bs); 1976 } 1977 for (i = 0; i < new_drain_count; i++) { 1978 bdrv_drained_begin(new_child_bs); 1979 } 1980 1981 if (!old_drain_count) { 1982 /* 1983 * Start a read operation that will yield, so it will not 1984 * complete before the node is drained. 1985 */ 1986 parent_s->yield_before_read = true; 1987 io_co = qemu_coroutine_create(test_replace_child_mid_drain_read_co, 1988 parent_blk); 1989 qemu_coroutine_enter(io_co); 1990 } 1991 1992 /* If we have started a read operation, it should have yielded */ 1993 g_assert(!parent_s->has_read); 1994 1995 /* Reset drained status so we can see what bdrv_replace_node() does */ 1996 parent_s->was_drained = false; 1997 parent_s->was_undrained = false; 1998 1999 g_assert(parent_bs->quiesce_counter == old_drain_count); 2000 bdrv_replace_node(old_child_bs, new_child_bs, &error_abort); 2001 g_assert(parent_bs->quiesce_counter == new_drain_count); 2002 2003 if (!old_drain_count && !new_drain_count) { 2004 /* 2005 * From undrained to undrained drains and undrains the parent, 2006 * because bdrv_replace_node() contains a drained section for 2007 * @old_child_bs. 2008 */ 2009 g_assert(parent_s->was_drained && parent_s->was_undrained); 2010 } else if (!old_drain_count && new_drain_count) { 2011 /* 2012 * From undrained to drained should drain the parent and keep 2013 * it that way. 2014 */ 2015 g_assert(parent_s->was_drained && !parent_s->was_undrained); 2016 } else if (old_drain_count && !new_drain_count) { 2017 /* 2018 * From drained to undrained should undrain the parent and 2019 * keep it that way. 2020 */ 2021 g_assert(!parent_s->was_drained && parent_s->was_undrained); 2022 } else /* if (old_drain_count && new_drain_count) */ { 2023 /* 2024 * From drained to drained must not undrain the parent at any 2025 * point 2026 */ 2027 g_assert(!parent_s->was_drained && !parent_s->was_undrained); 2028 } 2029 2030 if (!old_drain_count || !new_drain_count) { 2031 /* 2032 * If !old_drain_count, we have started a read request before 2033 * bdrv_replace_node(). If !new_drain_count, the parent must 2034 * have been undrained at some point, and 2035 * bdrv_replace_test_co_drain_end() starts a read request 2036 * then. 2037 */ 2038 g_assert(parent_s->has_read); 2039 } else { 2040 /* 2041 * If the parent was never undrained, there is no way to start 2042 * a read request. 2043 */ 2044 g_assert(!parent_s->has_read); 2045 } 2046 2047 /* A drained child must have not received any request */ 2048 g_assert(!(old_drain_count && old_child_s->has_read)); 2049 g_assert(!(new_drain_count && new_child_s->has_read)); 2050 2051 for (i = 0; i < new_drain_count; i++) { 2052 bdrv_drained_end(new_child_bs); 2053 } 2054 for (i = 0; i < old_drain_count; i++) { 2055 bdrv_drained_end(old_child_bs); 2056 } 2057 2058 /* 2059 * By now, bdrv_replace_test_co_drain_end() must have been called 2060 * at some point while the new child was attached to the parent. 2061 */ 2062 g_assert(parent_s->has_read); 2063 g_assert(new_child_s->has_read); 2064 2065 blk_unref(parent_blk); 2066 bdrv_unref(parent_bs); 2067 bdrv_unref(old_child_bs); 2068 bdrv_unref(new_child_bs); 2069 } 2070 2071 static void test_replace_child_mid_drain(void) 2072 { 2073 int old_drain_count, new_drain_count; 2074 2075 for (old_drain_count = 0; old_drain_count < 2; old_drain_count++) { 2076 for (new_drain_count = 0; new_drain_count < 2; new_drain_count++) { 2077 do_test_replace_child_mid_drain(old_drain_count, new_drain_count); 2078 } 2079 } 2080 } 2081 2082 int main(int argc, char **argv) 2083 { 2084 int ret; 2085 2086 bdrv_init(); 2087 qemu_init_main_loop(&error_abort); 2088 2089 g_test_init(&argc, &argv, NULL); 2090 qemu_event_init(&done_event, false); 2091 2092 g_test_add_func("/bdrv-drain/driver-cb/drain_all", test_drv_cb_drain_all); 2093 g_test_add_func("/bdrv-drain/driver-cb/drain", test_drv_cb_drain); 2094 2095 g_test_add_func("/bdrv-drain/driver-cb/co/drain_all", 2096 test_drv_cb_co_drain_all); 2097 g_test_add_func("/bdrv-drain/driver-cb/co/drain", test_drv_cb_co_drain); 2098 2099 g_test_add_func("/bdrv-drain/quiesce/drain_all", test_quiesce_drain_all); 2100 g_test_add_func("/bdrv-drain/quiesce/drain", test_quiesce_drain); 2101 2102 g_test_add_func("/bdrv-drain/quiesce/co/drain_all", 2103 test_quiesce_co_drain_all); 2104 g_test_add_func("/bdrv-drain/quiesce/co/drain", test_quiesce_co_drain); 2105 2106 g_test_add_func("/bdrv-drain/nested", test_nested); 2107 2108 g_test_add_func("/bdrv-drain/graph-change/drain_all", 2109 test_graph_change_drain_all); 2110 2111 g_test_add_func("/bdrv-drain/iothread/drain_all", test_iothread_drain_all); 2112 g_test_add_func("/bdrv-drain/iothread/drain", test_iothread_drain); 2113 2114 g_test_add_func("/bdrv-drain/blockjob/drain_all", test_blockjob_drain_all); 2115 g_test_add_func("/bdrv-drain/blockjob/drain", test_blockjob_drain); 2116 2117 g_test_add_func("/bdrv-drain/blockjob/error/drain_all", 2118 test_blockjob_error_drain_all); 2119 g_test_add_func("/bdrv-drain/blockjob/error/drain", 2120 test_blockjob_error_drain); 2121 2122 g_test_add_func("/bdrv-drain/blockjob/iothread/drain_all", 2123 test_blockjob_iothread_drain_all); 2124 g_test_add_func("/bdrv-drain/blockjob/iothread/drain", 2125 test_blockjob_iothread_drain); 2126 2127 g_test_add_func("/bdrv-drain/blockjob/iothread/error/drain_all", 2128 test_blockjob_iothread_error_drain_all); 2129 g_test_add_func("/bdrv-drain/blockjob/iothread/error/drain", 2130 test_blockjob_iothread_error_drain); 2131 2132 g_test_add_func("/bdrv-drain/deletion/drain", test_delete_by_drain); 2133 g_test_add_func("/bdrv-drain/detach/drain_all", test_detach_by_drain_all); 2134 g_test_add_func("/bdrv-drain/detach/drain", test_detach_by_drain); 2135 g_test_add_func("/bdrv-drain/detach/parent_cb", test_detach_by_parent_cb); 2136 g_test_add_func("/bdrv-drain/detach/driver_cb", test_detach_by_driver_cb); 2137 2138 g_test_add_func("/bdrv-drain/attach/drain", test_append_to_drained); 2139 2140 g_test_add_func("/bdrv-drain/set_aio_context", test_set_aio_context); 2141 2142 g_test_add_func("/bdrv-drain/blockjob/commit_by_drained_end", 2143 test_blockjob_commit_by_drained_end); 2144 2145 g_test_add_func("/bdrv-drain/bdrv_drop_intermediate/poll", 2146 test_drop_intermediate_poll); 2147 2148 g_test_add_func("/bdrv-drain/replace_child/mid-drain", 2149 test_replace_child_mid_drain); 2150 2151 ret = g_test_run(); 2152 qemu_event_destroy(&done_event); 2153 return ret; 2154 } 2155