1 /* 2 * Image mirroring 3 * 4 * Copyright Red Hat, Inc. 2012 5 * 6 * Authors: 7 * Paolo Bonzini <pbonzini@redhat.com> 8 * 9 * This work is licensed under the terms of the GNU LGPL, version 2 or later. 10 * See the COPYING.LIB file in the top-level directory. 11 * 12 */ 13 14 #include "trace.h" 15 #include "block/blockjob.h" 16 #include "block/block_int.h" 17 #include "qemu/ratelimit.h" 18 #include "qemu/bitmap.h" 19 20 #define SLICE_TIME 100000000ULL /* ns */ 21 #define MAX_IN_FLIGHT 16 22 23 /* The mirroring buffer is a list of granularity-sized chunks. 24 * Free chunks are organized in a list. 25 */ 26 typedef struct MirrorBuffer { 27 QSIMPLEQ_ENTRY(MirrorBuffer) next; 28 } MirrorBuffer; 29 30 typedef struct MirrorBlockJob { 31 BlockJob common; 32 RateLimit limit; 33 BlockDriverState *target; 34 BlockDriverState *base; 35 /* The name of the graph node to replace */ 36 char *replaces; 37 /* The BDS to replace */ 38 BlockDriverState *to_replace; 39 /* Used to block operations on the drive-mirror-replace target */ 40 Error *replace_blocker; 41 bool is_none_mode; 42 BlockdevOnError on_source_error, on_target_error; 43 bool synced; 44 bool should_complete; 45 int64_t sector_num; 46 int64_t granularity; 47 size_t buf_size; 48 int64_t bdev_length; 49 unsigned long *cow_bitmap; 50 BdrvDirtyBitmap *dirty_bitmap; 51 HBitmapIter hbi; 52 uint8_t *buf; 53 QSIMPLEQ_HEAD(, MirrorBuffer) buf_free; 54 int buf_free_count; 55 56 unsigned long *in_flight_bitmap; 57 int in_flight; 58 int sectors_in_flight; 59 int ret; 60 } MirrorBlockJob; 61 62 typedef struct MirrorOp { 63 MirrorBlockJob *s; 64 QEMUIOVector qiov; 65 int64_t sector_num; 66 int nb_sectors; 67 } MirrorOp; 68 69 static BlockErrorAction mirror_error_action(MirrorBlockJob *s, bool read, 70 int error) 71 { 72 s->synced = false; 73 if (read) { 74 return block_job_error_action(&s->common, s->common.bs, 75 s->on_source_error, true, error); 76 } else { 77 return block_job_error_action(&s->common, s->target, 78 s->on_target_error, false, error); 79 } 80 } 81 82 static void mirror_iteration_done(MirrorOp *op, int ret) 83 { 84 MirrorBlockJob *s = op->s; 85 struct iovec *iov; 86 int64_t chunk_num; 87 int i, nb_chunks, sectors_per_chunk; 88 89 trace_mirror_iteration_done(s, op->sector_num, op->nb_sectors, ret); 90 91 s->in_flight--; 92 s->sectors_in_flight -= op->nb_sectors; 93 iov = op->qiov.iov; 94 for (i = 0; i < op->qiov.niov; i++) { 95 MirrorBuffer *buf = (MirrorBuffer *) iov[i].iov_base; 96 QSIMPLEQ_INSERT_TAIL(&s->buf_free, buf, next); 97 s->buf_free_count++; 98 } 99 100 sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; 101 chunk_num = op->sector_num / sectors_per_chunk; 102 nb_chunks = op->nb_sectors / sectors_per_chunk; 103 bitmap_clear(s->in_flight_bitmap, chunk_num, nb_chunks); 104 if (ret >= 0) { 105 if (s->cow_bitmap) { 106 bitmap_set(s->cow_bitmap, chunk_num, nb_chunks); 107 } 108 s->common.offset += (uint64_t)op->nb_sectors * BDRV_SECTOR_SIZE; 109 } 110 111 qemu_iovec_destroy(&op->qiov); 112 g_slice_free(MirrorOp, op); 113 114 /* Enter coroutine when it is not sleeping. The coroutine sleeps to 115 * rate-limit itself. The coroutine will eventually resume since there is 116 * a sleep timeout so don't wake it early. 117 */ 118 if (s->common.busy) { 119 qemu_coroutine_enter(s->common.co, NULL); 120 } 121 } 122 123 static void mirror_write_complete(void *opaque, int ret) 124 { 125 MirrorOp *op = opaque; 126 MirrorBlockJob *s = op->s; 127 if (ret < 0) { 128 BlockDriverState *source = s->common.bs; 129 BlockErrorAction action; 130 131 bdrv_set_dirty_bitmap(source, s->dirty_bitmap, op->sector_num, 132 op->nb_sectors); 133 action = mirror_error_action(s, false, -ret); 134 if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) { 135 s->ret = ret; 136 } 137 } 138 mirror_iteration_done(op, ret); 139 } 140 141 static void mirror_read_complete(void *opaque, int ret) 142 { 143 MirrorOp *op = opaque; 144 MirrorBlockJob *s = op->s; 145 if (ret < 0) { 146 BlockDriverState *source = s->common.bs; 147 BlockErrorAction action; 148 149 bdrv_set_dirty_bitmap(source, s->dirty_bitmap, op->sector_num, 150 op->nb_sectors); 151 action = mirror_error_action(s, true, -ret); 152 if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) { 153 s->ret = ret; 154 } 155 156 mirror_iteration_done(op, ret); 157 return; 158 } 159 bdrv_aio_writev(s->target, op->sector_num, &op->qiov, op->nb_sectors, 160 mirror_write_complete, op); 161 } 162 163 static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) 164 { 165 BlockDriverState *source = s->common.bs; 166 int nb_sectors, sectors_per_chunk, nb_chunks; 167 int64_t end, sector_num, next_chunk, next_sector, hbitmap_next_sector; 168 uint64_t delay_ns = 0; 169 MirrorOp *op; 170 171 s->sector_num = hbitmap_iter_next(&s->hbi); 172 if (s->sector_num < 0) { 173 bdrv_dirty_iter_init(source, s->dirty_bitmap, &s->hbi); 174 s->sector_num = hbitmap_iter_next(&s->hbi); 175 trace_mirror_restart_iter(s, 176 bdrv_get_dirty_count(source, s->dirty_bitmap)); 177 assert(s->sector_num >= 0); 178 } 179 180 hbitmap_next_sector = s->sector_num; 181 sector_num = s->sector_num; 182 sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; 183 end = s->bdev_length / BDRV_SECTOR_SIZE; 184 185 /* Extend the QEMUIOVector to include all adjacent blocks that will 186 * be copied in this operation. 187 * 188 * We have to do this if we have no backing file yet in the destination, 189 * and the cluster size is very large. Then we need to do COW ourselves. 190 * The first time a cluster is copied, copy it entirely. Note that, 191 * because both the granularity and the cluster size are powers of two, 192 * the number of sectors to copy cannot exceed one cluster. 193 * 194 * We also want to extend the QEMUIOVector to include more adjacent 195 * dirty blocks if possible, to limit the number of I/O operations and 196 * run efficiently even with a small granularity. 197 */ 198 nb_chunks = 0; 199 nb_sectors = 0; 200 next_sector = sector_num; 201 next_chunk = sector_num / sectors_per_chunk; 202 203 /* Wait for I/O to this cluster (from a previous iteration) to be done. */ 204 while (test_bit(next_chunk, s->in_flight_bitmap)) { 205 trace_mirror_yield_in_flight(s, sector_num, s->in_flight); 206 qemu_coroutine_yield(); 207 } 208 209 do { 210 int added_sectors, added_chunks; 211 212 if (!bdrv_get_dirty(source, s->dirty_bitmap, next_sector) || 213 test_bit(next_chunk, s->in_flight_bitmap)) { 214 assert(nb_sectors > 0); 215 break; 216 } 217 218 added_sectors = sectors_per_chunk; 219 if (s->cow_bitmap && !test_bit(next_chunk, s->cow_bitmap)) { 220 bdrv_round_to_clusters(s->target, 221 next_sector, added_sectors, 222 &next_sector, &added_sectors); 223 224 /* On the first iteration, the rounding may make us copy 225 * sectors before the first dirty one. 226 */ 227 if (next_sector < sector_num) { 228 assert(nb_sectors == 0); 229 sector_num = next_sector; 230 next_chunk = next_sector / sectors_per_chunk; 231 } 232 } 233 234 added_sectors = MIN(added_sectors, end - (sector_num + nb_sectors)); 235 added_chunks = (added_sectors + sectors_per_chunk - 1) / sectors_per_chunk; 236 237 /* When doing COW, it may happen that there is not enough space for 238 * a full cluster. Wait if that is the case. 239 */ 240 while (nb_chunks == 0 && s->buf_free_count < added_chunks) { 241 trace_mirror_yield_buf_busy(s, nb_chunks, s->in_flight); 242 qemu_coroutine_yield(); 243 } 244 if (s->buf_free_count < nb_chunks + added_chunks) { 245 trace_mirror_break_buf_busy(s, nb_chunks, s->in_flight); 246 break; 247 } 248 249 /* We have enough free space to copy these sectors. */ 250 bitmap_set(s->in_flight_bitmap, next_chunk, added_chunks); 251 252 nb_sectors += added_sectors; 253 nb_chunks += added_chunks; 254 next_sector += added_sectors; 255 next_chunk += added_chunks; 256 if (!s->synced && s->common.speed) { 257 delay_ns = ratelimit_calculate_delay(&s->limit, added_sectors); 258 } 259 } while (delay_ns == 0 && next_sector < end); 260 261 /* Allocate a MirrorOp that is used as an AIO callback. */ 262 op = g_slice_new(MirrorOp); 263 op->s = s; 264 op->sector_num = sector_num; 265 op->nb_sectors = nb_sectors; 266 267 /* Now make a QEMUIOVector taking enough granularity-sized chunks 268 * from s->buf_free. 269 */ 270 qemu_iovec_init(&op->qiov, nb_chunks); 271 next_sector = sector_num; 272 while (nb_chunks-- > 0) { 273 MirrorBuffer *buf = QSIMPLEQ_FIRST(&s->buf_free); 274 size_t remaining = (nb_sectors * BDRV_SECTOR_SIZE) - op->qiov.size; 275 276 QSIMPLEQ_REMOVE_HEAD(&s->buf_free, next); 277 s->buf_free_count--; 278 qemu_iovec_add(&op->qiov, buf, MIN(s->granularity, remaining)); 279 280 /* Advance the HBitmapIter in parallel, so that we do not examine 281 * the same sector twice. 282 */ 283 if (next_sector > hbitmap_next_sector 284 && bdrv_get_dirty(source, s->dirty_bitmap, next_sector)) { 285 hbitmap_next_sector = hbitmap_iter_next(&s->hbi); 286 } 287 288 next_sector += sectors_per_chunk; 289 } 290 291 bdrv_reset_dirty_bitmap(source, s->dirty_bitmap, sector_num, 292 nb_sectors); 293 294 /* Copy the dirty cluster. */ 295 s->in_flight++; 296 s->sectors_in_flight += nb_sectors; 297 trace_mirror_one_iteration(s, sector_num, nb_sectors); 298 bdrv_aio_readv(source, sector_num, &op->qiov, nb_sectors, 299 mirror_read_complete, op); 300 return delay_ns; 301 } 302 303 static void mirror_free_init(MirrorBlockJob *s) 304 { 305 int granularity = s->granularity; 306 size_t buf_size = s->buf_size; 307 uint8_t *buf = s->buf; 308 309 assert(s->buf_free_count == 0); 310 QSIMPLEQ_INIT(&s->buf_free); 311 while (buf_size != 0) { 312 MirrorBuffer *cur = (MirrorBuffer *)buf; 313 QSIMPLEQ_INSERT_TAIL(&s->buf_free, cur, next); 314 s->buf_free_count++; 315 buf_size -= granularity; 316 buf += granularity; 317 } 318 } 319 320 static void mirror_drain(MirrorBlockJob *s) 321 { 322 while (s->in_flight > 0) { 323 qemu_coroutine_yield(); 324 } 325 } 326 327 typedef struct { 328 int ret; 329 } MirrorExitData; 330 331 static void mirror_exit(BlockJob *job, void *opaque) 332 { 333 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 334 MirrorExitData *data = opaque; 335 AioContext *replace_aio_context = NULL; 336 337 if (s->to_replace) { 338 replace_aio_context = bdrv_get_aio_context(s->to_replace); 339 aio_context_acquire(replace_aio_context); 340 } 341 342 if (s->should_complete && data->ret == 0) { 343 BlockDriverState *to_replace = s->common.bs; 344 if (s->to_replace) { 345 to_replace = s->to_replace; 346 } 347 if (bdrv_get_flags(s->target) != bdrv_get_flags(to_replace)) { 348 bdrv_reopen(s->target, bdrv_get_flags(to_replace), NULL); 349 } 350 bdrv_swap(s->target, to_replace); 351 if (s->common.driver->job_type == BLOCK_JOB_TYPE_COMMIT) { 352 /* drop the bs loop chain formed by the swap: break the loop then 353 * trigger the unref from the top one */ 354 BlockDriverState *p = s->base->backing_hd; 355 bdrv_set_backing_hd(s->base, NULL); 356 bdrv_unref(p); 357 } 358 } 359 if (s->to_replace) { 360 bdrv_op_unblock_all(s->to_replace, s->replace_blocker); 361 error_free(s->replace_blocker); 362 bdrv_unref(s->to_replace); 363 } 364 if (replace_aio_context) { 365 aio_context_release(replace_aio_context); 366 } 367 g_free(s->replaces); 368 bdrv_unref(s->target); 369 block_job_completed(&s->common, data->ret); 370 g_free(data); 371 } 372 373 static void coroutine_fn mirror_run(void *opaque) 374 { 375 MirrorBlockJob *s = opaque; 376 MirrorExitData *data; 377 BlockDriverState *bs = s->common.bs; 378 int64_t sector_num, end, sectors_per_chunk, length; 379 uint64_t last_pause_ns; 380 BlockDriverInfo bdi; 381 char backing_filename[1024]; 382 int ret = 0; 383 int n; 384 385 if (block_job_is_cancelled(&s->common)) { 386 goto immediate_exit; 387 } 388 389 s->bdev_length = bdrv_getlength(bs); 390 if (s->bdev_length < 0) { 391 ret = s->bdev_length; 392 goto immediate_exit; 393 } else if (s->bdev_length == 0) { 394 /* Report BLOCK_JOB_READY and wait for complete. */ 395 block_job_event_ready(&s->common); 396 s->synced = true; 397 while (!block_job_is_cancelled(&s->common) && !s->should_complete) { 398 block_job_yield(&s->common); 399 } 400 s->common.cancelled = false; 401 goto immediate_exit; 402 } 403 404 length = DIV_ROUND_UP(s->bdev_length, s->granularity); 405 s->in_flight_bitmap = bitmap_new(length); 406 407 /* If we have no backing file yet in the destination, we cannot let 408 * the destination do COW. Instead, we copy sectors around the 409 * dirty data if needed. We need a bitmap to do that. 410 */ 411 bdrv_get_backing_filename(s->target, backing_filename, 412 sizeof(backing_filename)); 413 if (backing_filename[0] && !s->target->backing_hd) { 414 ret = bdrv_get_info(s->target, &bdi); 415 if (ret < 0) { 416 goto immediate_exit; 417 } 418 if (s->granularity < bdi.cluster_size) { 419 s->buf_size = MAX(s->buf_size, bdi.cluster_size); 420 s->cow_bitmap = bitmap_new(length); 421 } 422 } 423 424 end = s->bdev_length / BDRV_SECTOR_SIZE; 425 s->buf = qemu_try_blockalign(bs, s->buf_size); 426 if (s->buf == NULL) { 427 ret = -ENOMEM; 428 goto immediate_exit; 429 } 430 431 sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; 432 mirror_free_init(s); 433 434 if (!s->is_none_mode) { 435 /* First part, loop on the sectors and initialize the dirty bitmap. */ 436 BlockDriverState *base = s->base; 437 for (sector_num = 0; sector_num < end; ) { 438 int64_t next = (sector_num | (sectors_per_chunk - 1)) + 1; 439 ret = bdrv_is_allocated_above(bs, base, 440 sector_num, next - sector_num, &n); 441 442 if (ret < 0) { 443 goto immediate_exit; 444 } 445 446 assert(n > 0); 447 if (ret == 1) { 448 bdrv_set_dirty_bitmap(bs, s->dirty_bitmap, sector_num, n); 449 sector_num = next; 450 } else { 451 sector_num += n; 452 } 453 } 454 } 455 456 bdrv_dirty_iter_init(bs, s->dirty_bitmap, &s->hbi); 457 last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 458 for (;;) { 459 uint64_t delay_ns = 0; 460 int64_t cnt; 461 bool should_complete; 462 463 if (s->ret < 0) { 464 ret = s->ret; 465 goto immediate_exit; 466 } 467 468 cnt = bdrv_get_dirty_count(bs, s->dirty_bitmap); 469 /* s->common.offset contains the number of bytes already processed so 470 * far, cnt is the number of dirty sectors remaining and 471 * s->sectors_in_flight is the number of sectors currently being 472 * processed; together those are the current total operation length */ 473 s->common.len = s->common.offset + 474 (cnt + s->sectors_in_flight) * BDRV_SECTOR_SIZE; 475 476 /* Note that even when no rate limit is applied we need to yield 477 * periodically with no pending I/O so that qemu_aio_flush() returns. 478 * We do so every SLICE_TIME nanoseconds, or when there is an error, 479 * or when the source is clean, whichever comes first. 480 */ 481 if (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - last_pause_ns < SLICE_TIME && 482 s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) { 483 if (s->in_flight == MAX_IN_FLIGHT || s->buf_free_count == 0 || 484 (cnt == 0 && s->in_flight > 0)) { 485 trace_mirror_yield(s, s->in_flight, s->buf_free_count, cnt); 486 qemu_coroutine_yield(); 487 continue; 488 } else if (cnt != 0) { 489 delay_ns = mirror_iteration(s); 490 if (delay_ns == 0) { 491 continue; 492 } 493 } 494 } 495 496 should_complete = false; 497 if (s->in_flight == 0 && cnt == 0) { 498 trace_mirror_before_flush(s); 499 ret = bdrv_flush(s->target); 500 if (ret < 0) { 501 if (mirror_error_action(s, false, -ret) == 502 BLOCK_ERROR_ACTION_REPORT) { 503 goto immediate_exit; 504 } 505 } else { 506 /* We're out of the streaming phase. From now on, if the job 507 * is cancelled we will actually complete all pending I/O and 508 * report completion. This way, block-job-cancel will leave 509 * the target in a consistent state. 510 */ 511 if (!s->synced) { 512 block_job_event_ready(&s->common); 513 s->synced = true; 514 } 515 516 should_complete = s->should_complete || 517 block_job_is_cancelled(&s->common); 518 cnt = bdrv_get_dirty_count(bs, s->dirty_bitmap); 519 } 520 } 521 522 if (cnt == 0 && should_complete) { 523 /* The dirty bitmap is not updated while operations are pending. 524 * If we're about to exit, wait for pending operations before 525 * calling bdrv_get_dirty_count(bs), or we may exit while the 526 * source has dirty data to copy! 527 * 528 * Note that I/O can be submitted by the guest while 529 * mirror_populate runs. 530 */ 531 trace_mirror_before_drain(s, cnt); 532 bdrv_drain(bs); 533 cnt = bdrv_get_dirty_count(bs, s->dirty_bitmap); 534 } 535 536 ret = 0; 537 trace_mirror_before_sleep(s, cnt, s->synced, delay_ns); 538 if (!s->synced) { 539 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); 540 if (block_job_is_cancelled(&s->common)) { 541 break; 542 } 543 } else if (!should_complete) { 544 delay_ns = (s->in_flight == 0 && cnt == 0 ? SLICE_TIME : 0); 545 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); 546 } else if (cnt == 0) { 547 /* The two disks are in sync. Exit and report successful 548 * completion. 549 */ 550 assert(QLIST_EMPTY(&bs->tracked_requests)); 551 s->common.cancelled = false; 552 break; 553 } 554 last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 555 } 556 557 immediate_exit: 558 if (s->in_flight > 0) { 559 /* We get here only if something went wrong. Either the job failed, 560 * or it was cancelled prematurely so that we do not guarantee that 561 * the target is a copy of the source. 562 */ 563 assert(ret < 0 || (!s->synced && block_job_is_cancelled(&s->common))); 564 mirror_drain(s); 565 } 566 567 assert(s->in_flight == 0); 568 qemu_vfree(s->buf); 569 g_free(s->cow_bitmap); 570 g_free(s->in_flight_bitmap); 571 bdrv_release_dirty_bitmap(bs, s->dirty_bitmap); 572 bdrv_iostatus_disable(s->target); 573 574 data = g_malloc(sizeof(*data)); 575 data->ret = ret; 576 block_job_defer_to_main_loop(&s->common, mirror_exit, data); 577 } 578 579 static void mirror_set_speed(BlockJob *job, int64_t speed, Error **errp) 580 { 581 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 582 583 if (speed < 0) { 584 error_set(errp, QERR_INVALID_PARAMETER, "speed"); 585 return; 586 } 587 ratelimit_set_speed(&s->limit, speed / BDRV_SECTOR_SIZE, SLICE_TIME); 588 } 589 590 static void mirror_iostatus_reset(BlockJob *job) 591 { 592 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 593 594 bdrv_iostatus_reset(s->target); 595 } 596 597 static void mirror_complete(BlockJob *job, Error **errp) 598 { 599 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 600 Error *local_err = NULL; 601 int ret; 602 603 ret = bdrv_open_backing_file(s->target, NULL, &local_err); 604 if (ret < 0) { 605 error_propagate(errp, local_err); 606 return; 607 } 608 if (!s->synced) { 609 error_set(errp, QERR_BLOCK_JOB_NOT_READY, 610 bdrv_get_device_name(job->bs)); 611 return; 612 } 613 614 /* check the target bs is not blocked and block all operations on it */ 615 if (s->replaces) { 616 AioContext *replace_aio_context; 617 618 s->to_replace = check_to_replace_node(s->replaces, &local_err); 619 if (!s->to_replace) { 620 error_propagate(errp, local_err); 621 return; 622 } 623 624 replace_aio_context = bdrv_get_aio_context(s->to_replace); 625 aio_context_acquire(replace_aio_context); 626 627 error_setg(&s->replace_blocker, 628 "block device is in use by block-job-complete"); 629 bdrv_op_block_all(s->to_replace, s->replace_blocker); 630 bdrv_ref(s->to_replace); 631 632 aio_context_release(replace_aio_context); 633 } 634 635 s->should_complete = true; 636 block_job_resume(job); 637 } 638 639 static const BlockJobDriver mirror_job_driver = { 640 .instance_size = sizeof(MirrorBlockJob), 641 .job_type = BLOCK_JOB_TYPE_MIRROR, 642 .set_speed = mirror_set_speed, 643 .iostatus_reset= mirror_iostatus_reset, 644 .complete = mirror_complete, 645 }; 646 647 static const BlockJobDriver commit_active_job_driver = { 648 .instance_size = sizeof(MirrorBlockJob), 649 .job_type = BLOCK_JOB_TYPE_COMMIT, 650 .set_speed = mirror_set_speed, 651 .iostatus_reset 652 = mirror_iostatus_reset, 653 .complete = mirror_complete, 654 }; 655 656 static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target, 657 const char *replaces, 658 int64_t speed, int64_t granularity, 659 int64_t buf_size, 660 BlockdevOnError on_source_error, 661 BlockdevOnError on_target_error, 662 BlockCompletionFunc *cb, 663 void *opaque, Error **errp, 664 const BlockJobDriver *driver, 665 bool is_none_mode, BlockDriverState *base) 666 { 667 MirrorBlockJob *s; 668 669 if (granularity == 0) { 670 /* Choose the default granularity based on the target file's cluster 671 * size, clamped between 4k and 64k. */ 672 BlockDriverInfo bdi; 673 if (bdrv_get_info(target, &bdi) >= 0 && bdi.cluster_size != 0) { 674 granularity = MAX(4096, bdi.cluster_size); 675 granularity = MIN(65536, granularity); 676 } else { 677 granularity = 65536; 678 } 679 } 680 681 assert ((granularity & (granularity - 1)) == 0); 682 683 if ((on_source_error == BLOCKDEV_ON_ERROR_STOP || 684 on_source_error == BLOCKDEV_ON_ERROR_ENOSPC) && 685 !bdrv_iostatus_is_enabled(bs)) { 686 error_set(errp, QERR_INVALID_PARAMETER, "on-source-error"); 687 return; 688 } 689 690 691 s = block_job_create(driver, bs, speed, cb, opaque, errp); 692 if (!s) { 693 return; 694 } 695 696 s->replaces = g_strdup(replaces); 697 s->on_source_error = on_source_error; 698 s->on_target_error = on_target_error; 699 s->target = target; 700 s->is_none_mode = is_none_mode; 701 s->base = base; 702 s->granularity = granularity; 703 s->buf_size = MAX(buf_size, granularity); 704 705 s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, errp); 706 if (!s->dirty_bitmap) { 707 return; 708 } 709 bdrv_set_enable_write_cache(s->target, true); 710 bdrv_set_on_error(s->target, on_target_error, on_target_error); 711 bdrv_iostatus_enable(s->target); 712 s->common.co = qemu_coroutine_create(mirror_run); 713 trace_mirror_start(bs, s, s->common.co, opaque); 714 qemu_coroutine_enter(s->common.co, s); 715 } 716 717 void mirror_start(BlockDriverState *bs, BlockDriverState *target, 718 const char *replaces, 719 int64_t speed, int64_t granularity, int64_t buf_size, 720 MirrorSyncMode mode, BlockdevOnError on_source_error, 721 BlockdevOnError on_target_error, 722 BlockCompletionFunc *cb, 723 void *opaque, Error **errp) 724 { 725 bool is_none_mode; 726 BlockDriverState *base; 727 728 is_none_mode = mode == MIRROR_SYNC_MODE_NONE; 729 base = mode == MIRROR_SYNC_MODE_TOP ? bs->backing_hd : NULL; 730 mirror_start_job(bs, target, replaces, 731 speed, granularity, buf_size, 732 on_source_error, on_target_error, cb, opaque, errp, 733 &mirror_job_driver, is_none_mode, base); 734 } 735 736 void commit_active_start(BlockDriverState *bs, BlockDriverState *base, 737 int64_t speed, 738 BlockdevOnError on_error, 739 BlockCompletionFunc *cb, 740 void *opaque, Error **errp) 741 { 742 int64_t length, base_length; 743 int orig_base_flags; 744 int ret; 745 Error *local_err = NULL; 746 747 orig_base_flags = bdrv_get_flags(base); 748 749 if (bdrv_reopen(base, bs->open_flags, errp)) { 750 return; 751 } 752 753 length = bdrv_getlength(bs); 754 if (length < 0) { 755 error_setg_errno(errp, -length, 756 "Unable to determine length of %s", bs->filename); 757 goto error_restore_flags; 758 } 759 760 base_length = bdrv_getlength(base); 761 if (base_length < 0) { 762 error_setg_errno(errp, -base_length, 763 "Unable to determine length of %s", base->filename); 764 goto error_restore_flags; 765 } 766 767 if (length > base_length) { 768 ret = bdrv_truncate(base, length); 769 if (ret < 0) { 770 error_setg_errno(errp, -ret, 771 "Top image %s is larger than base image %s, and " 772 "resize of base image failed", 773 bs->filename, base->filename); 774 goto error_restore_flags; 775 } 776 } 777 778 bdrv_ref(base); 779 mirror_start_job(bs, base, NULL, speed, 0, 0, 780 on_error, on_error, cb, opaque, &local_err, 781 &commit_active_job_driver, false, base); 782 if (local_err) { 783 error_propagate(errp, local_err); 784 goto error_restore_flags; 785 } 786 787 return; 788 789 error_restore_flags: 790 /* ignore error and errp for bdrv_reopen, because we want to propagate 791 * the original error */ 792 bdrv_reopen(base, orig_base_flags, NULL); 793 return; 794 } 795