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 "qapi/qmp/qerror.h" 18 #include "qemu/ratelimit.h" 19 #include "qemu/bitmap.h" 20 21 #define SLICE_TIME 100000000ULL /* ns */ 22 #define MAX_IN_FLIGHT 16 23 #define DEFAULT_MIRROR_BUF_SIZE (10 << 20) 24 25 /* The mirroring buffer is a list of granularity-sized chunks. 26 * Free chunks are organized in a list. 27 */ 28 typedef struct MirrorBuffer { 29 QSIMPLEQ_ENTRY(MirrorBuffer) next; 30 } MirrorBuffer; 31 32 typedef struct MirrorBlockJob { 33 BlockJob common; 34 RateLimit limit; 35 BlockDriverState *target; 36 BlockDriverState *base; 37 /* The name of the graph node to replace */ 38 char *replaces; 39 /* The BDS to replace */ 40 BlockDriverState *to_replace; 41 /* Used to block operations on the drive-mirror-replace target */ 42 Error *replace_blocker; 43 bool is_none_mode; 44 BlockdevOnError on_source_error, on_target_error; 45 bool synced; 46 bool should_complete; 47 int64_t sector_num; 48 int64_t granularity; 49 size_t buf_size; 50 int64_t bdev_length; 51 unsigned long *cow_bitmap; 52 BdrvDirtyBitmap *dirty_bitmap; 53 HBitmapIter hbi; 54 uint8_t *buf; 55 QSIMPLEQ_HEAD(, MirrorBuffer) buf_free; 56 int buf_free_count; 57 58 unsigned long *in_flight_bitmap; 59 int in_flight; 60 int sectors_in_flight; 61 int ret; 62 bool unmap; 63 } MirrorBlockJob; 64 65 typedef struct MirrorOp { 66 MirrorBlockJob *s; 67 QEMUIOVector qiov; 68 int64_t sector_num; 69 int nb_sectors; 70 } MirrorOp; 71 72 static BlockErrorAction mirror_error_action(MirrorBlockJob *s, bool read, 73 int error) 74 { 75 s->synced = false; 76 if (read) { 77 return block_job_error_action(&s->common, s->common.bs, 78 s->on_source_error, true, error); 79 } else { 80 return block_job_error_action(&s->common, s->target, 81 s->on_target_error, false, error); 82 } 83 } 84 85 static void mirror_iteration_done(MirrorOp *op, int ret) 86 { 87 MirrorBlockJob *s = op->s; 88 struct iovec *iov; 89 int64_t chunk_num; 90 int i, nb_chunks, sectors_per_chunk; 91 92 trace_mirror_iteration_done(s, op->sector_num, op->nb_sectors, ret); 93 94 s->in_flight--; 95 s->sectors_in_flight -= op->nb_sectors; 96 iov = op->qiov.iov; 97 for (i = 0; i < op->qiov.niov; i++) { 98 MirrorBuffer *buf = (MirrorBuffer *) iov[i].iov_base; 99 QSIMPLEQ_INSERT_TAIL(&s->buf_free, buf, next); 100 s->buf_free_count++; 101 } 102 103 sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; 104 chunk_num = op->sector_num / sectors_per_chunk; 105 nb_chunks = op->nb_sectors / sectors_per_chunk; 106 bitmap_clear(s->in_flight_bitmap, chunk_num, nb_chunks); 107 if (ret >= 0) { 108 if (s->cow_bitmap) { 109 bitmap_set(s->cow_bitmap, chunk_num, nb_chunks); 110 } 111 s->common.offset += (uint64_t)op->nb_sectors * BDRV_SECTOR_SIZE; 112 } 113 114 qemu_iovec_destroy(&op->qiov); 115 g_slice_free(MirrorOp, op); 116 117 /* Enter coroutine when it is not sleeping. The coroutine sleeps to 118 * rate-limit itself. The coroutine will eventually resume since there is 119 * a sleep timeout so don't wake it early. 120 */ 121 if (s->common.busy) { 122 qemu_coroutine_enter(s->common.co, NULL); 123 } 124 } 125 126 static void mirror_write_complete(void *opaque, int ret) 127 { 128 MirrorOp *op = opaque; 129 MirrorBlockJob *s = op->s; 130 if (ret < 0) { 131 BlockErrorAction action; 132 133 bdrv_set_dirty_bitmap(s->dirty_bitmap, op->sector_num, op->nb_sectors); 134 action = mirror_error_action(s, false, -ret); 135 if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) { 136 s->ret = ret; 137 } 138 } 139 mirror_iteration_done(op, ret); 140 } 141 142 static void mirror_read_complete(void *opaque, int ret) 143 { 144 MirrorOp *op = opaque; 145 MirrorBlockJob *s = op->s; 146 if (ret < 0) { 147 BlockErrorAction action; 148 149 bdrv_set_dirty_bitmap(s->dirty_bitmap, op->sector_num, op->nb_sectors); 150 action = mirror_error_action(s, true, -ret); 151 if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) { 152 s->ret = ret; 153 } 154 155 mirror_iteration_done(op, ret); 156 return; 157 } 158 bdrv_aio_writev(s->target, op->sector_num, &op->qiov, op->nb_sectors, 159 mirror_write_complete, op); 160 } 161 162 static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) 163 { 164 BlockDriverState *source = s->common.bs; 165 int nb_sectors, sectors_per_chunk, nb_chunks; 166 int64_t end, sector_num, next_chunk, next_sector, hbitmap_next_sector; 167 uint64_t delay_ns = 0; 168 MirrorOp *op; 169 int pnum; 170 int64_t ret; 171 172 s->sector_num = hbitmap_iter_next(&s->hbi); 173 if (s->sector_num < 0) { 174 bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi); 175 s->sector_num = hbitmap_iter_next(&s->hbi); 176 trace_mirror_restart_iter(s, bdrv_get_dirty_count(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(s->dirty_bitmap, sector_num, nb_sectors); 292 293 /* Copy the dirty cluster. */ 294 s->in_flight++; 295 s->sectors_in_flight += nb_sectors; 296 trace_mirror_one_iteration(s, sector_num, nb_sectors); 297 298 ret = bdrv_get_block_status_above(source, NULL, sector_num, 299 nb_sectors, &pnum); 300 if (ret < 0 || pnum < nb_sectors || 301 (ret & BDRV_BLOCK_DATA && !(ret & BDRV_BLOCK_ZERO))) { 302 bdrv_aio_readv(source, sector_num, &op->qiov, nb_sectors, 303 mirror_read_complete, op); 304 } else if (ret & BDRV_BLOCK_ZERO) { 305 bdrv_aio_write_zeroes(s->target, sector_num, op->nb_sectors, 306 s->unmap ? BDRV_REQ_MAY_UNMAP : 0, 307 mirror_write_complete, op); 308 } else { 309 assert(!(ret & BDRV_BLOCK_DATA)); 310 bdrv_aio_discard(s->target, sector_num, op->nb_sectors, 311 mirror_write_complete, op); 312 } 313 return delay_ns; 314 } 315 316 static void mirror_free_init(MirrorBlockJob *s) 317 { 318 int granularity = s->granularity; 319 size_t buf_size = s->buf_size; 320 uint8_t *buf = s->buf; 321 322 assert(s->buf_free_count == 0); 323 QSIMPLEQ_INIT(&s->buf_free); 324 while (buf_size != 0) { 325 MirrorBuffer *cur = (MirrorBuffer *)buf; 326 QSIMPLEQ_INSERT_TAIL(&s->buf_free, cur, next); 327 s->buf_free_count++; 328 buf_size -= granularity; 329 buf += granularity; 330 } 331 } 332 333 static void mirror_drain(MirrorBlockJob *s) 334 { 335 while (s->in_flight > 0) { 336 qemu_coroutine_yield(); 337 } 338 } 339 340 typedef struct { 341 int ret; 342 } MirrorExitData; 343 344 static void mirror_exit(BlockJob *job, void *opaque) 345 { 346 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 347 MirrorExitData *data = opaque; 348 AioContext *replace_aio_context = NULL; 349 350 if (s->to_replace) { 351 replace_aio_context = bdrv_get_aio_context(s->to_replace); 352 aio_context_acquire(replace_aio_context); 353 } 354 355 if (s->should_complete && data->ret == 0) { 356 BlockDriverState *to_replace = s->common.bs; 357 if (s->to_replace) { 358 to_replace = s->to_replace; 359 } 360 if (bdrv_get_flags(s->target) != bdrv_get_flags(to_replace)) { 361 bdrv_reopen(s->target, bdrv_get_flags(to_replace), NULL); 362 } 363 bdrv_swap(s->target, to_replace); 364 if (s->common.driver->job_type == BLOCK_JOB_TYPE_COMMIT) { 365 /* drop the bs loop chain formed by the swap: break the loop then 366 * trigger the unref from the top one */ 367 BlockDriverState *p = s->base->backing_hd; 368 bdrv_set_backing_hd(s->base, NULL); 369 bdrv_unref(p); 370 } 371 } 372 if (s->to_replace) { 373 bdrv_op_unblock_all(s->to_replace, s->replace_blocker); 374 error_free(s->replace_blocker); 375 bdrv_unref(s->to_replace); 376 } 377 if (replace_aio_context) { 378 aio_context_release(replace_aio_context); 379 } 380 g_free(s->replaces); 381 bdrv_unref(s->target); 382 block_job_completed(&s->common, data->ret); 383 g_free(data); 384 } 385 386 static void coroutine_fn mirror_run(void *opaque) 387 { 388 MirrorBlockJob *s = opaque; 389 MirrorExitData *data; 390 BlockDriverState *bs = s->common.bs; 391 int64_t sector_num, end, sectors_per_chunk, length; 392 uint64_t last_pause_ns; 393 BlockDriverInfo bdi; 394 char backing_filename[2]; /* we only need 2 characters because we are only 395 checking for a NULL string */ 396 int ret = 0; 397 int n; 398 399 if (block_job_is_cancelled(&s->common)) { 400 goto immediate_exit; 401 } 402 403 s->bdev_length = bdrv_getlength(bs); 404 if (s->bdev_length < 0) { 405 ret = s->bdev_length; 406 goto immediate_exit; 407 } else if (s->bdev_length == 0) { 408 /* Report BLOCK_JOB_READY and wait for complete. */ 409 block_job_event_ready(&s->common); 410 s->synced = true; 411 while (!block_job_is_cancelled(&s->common) && !s->should_complete) { 412 block_job_yield(&s->common); 413 } 414 s->common.cancelled = false; 415 goto immediate_exit; 416 } 417 418 length = DIV_ROUND_UP(s->bdev_length, s->granularity); 419 s->in_flight_bitmap = bitmap_new(length); 420 421 /* If we have no backing file yet in the destination, we cannot let 422 * the destination do COW. Instead, we copy sectors around the 423 * dirty data if needed. We need a bitmap to do that. 424 */ 425 bdrv_get_backing_filename(s->target, backing_filename, 426 sizeof(backing_filename)); 427 if (backing_filename[0] && !s->target->backing_hd) { 428 ret = bdrv_get_info(s->target, &bdi); 429 if (ret < 0) { 430 goto immediate_exit; 431 } 432 if (s->granularity < bdi.cluster_size) { 433 s->buf_size = MAX(s->buf_size, bdi.cluster_size); 434 s->cow_bitmap = bitmap_new(length); 435 } 436 } 437 438 end = s->bdev_length / BDRV_SECTOR_SIZE; 439 s->buf = qemu_try_blockalign(bs, s->buf_size); 440 if (s->buf == NULL) { 441 ret = -ENOMEM; 442 goto immediate_exit; 443 } 444 445 sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; 446 mirror_free_init(s); 447 448 last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 449 if (!s->is_none_mode) { 450 /* First part, loop on the sectors and initialize the dirty bitmap. */ 451 BlockDriverState *base = s->base; 452 for (sector_num = 0; sector_num < end; ) { 453 int64_t next = (sector_num | (sectors_per_chunk - 1)) + 1; 454 int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 455 456 if (now - last_pause_ns > SLICE_TIME) { 457 last_pause_ns = now; 458 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, 0); 459 } 460 461 if (block_job_is_cancelled(&s->common)) { 462 goto immediate_exit; 463 } 464 465 ret = bdrv_is_allocated_above(bs, base, 466 sector_num, next - sector_num, &n); 467 468 if (ret < 0) { 469 goto immediate_exit; 470 } 471 472 assert(n > 0); 473 if (ret == 1) { 474 bdrv_set_dirty_bitmap(s->dirty_bitmap, sector_num, n); 475 sector_num = next; 476 } else { 477 sector_num += n; 478 } 479 } 480 } 481 482 bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi); 483 for (;;) { 484 uint64_t delay_ns = 0; 485 int64_t cnt; 486 bool should_complete; 487 488 if (s->ret < 0) { 489 ret = s->ret; 490 goto immediate_exit; 491 } 492 493 cnt = bdrv_get_dirty_count(s->dirty_bitmap); 494 /* s->common.offset contains the number of bytes already processed so 495 * far, cnt is the number of dirty sectors remaining and 496 * s->sectors_in_flight is the number of sectors currently being 497 * processed; together those are the current total operation length */ 498 s->common.len = s->common.offset + 499 (cnt + s->sectors_in_flight) * BDRV_SECTOR_SIZE; 500 501 /* Note that even when no rate limit is applied we need to yield 502 * periodically with no pending I/O so that bdrv_drain_all() returns. 503 * We do so every SLICE_TIME nanoseconds, or when there is an error, 504 * or when the source is clean, whichever comes first. 505 */ 506 if (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - last_pause_ns < SLICE_TIME && 507 s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) { 508 if (s->in_flight == MAX_IN_FLIGHT || s->buf_free_count == 0 || 509 (cnt == 0 && s->in_flight > 0)) { 510 trace_mirror_yield(s, s->in_flight, s->buf_free_count, cnt); 511 qemu_coroutine_yield(); 512 continue; 513 } else if (cnt != 0) { 514 delay_ns = mirror_iteration(s); 515 } 516 } 517 518 should_complete = false; 519 if (s->in_flight == 0 && cnt == 0) { 520 trace_mirror_before_flush(s); 521 ret = bdrv_flush(s->target); 522 if (ret < 0) { 523 if (mirror_error_action(s, false, -ret) == 524 BLOCK_ERROR_ACTION_REPORT) { 525 goto immediate_exit; 526 } 527 } else { 528 /* We're out of the streaming phase. From now on, if the job 529 * is cancelled we will actually complete all pending I/O and 530 * report completion. This way, block-job-cancel will leave 531 * the target in a consistent state. 532 */ 533 if (!s->synced) { 534 block_job_event_ready(&s->common); 535 s->synced = true; 536 } 537 538 should_complete = s->should_complete || 539 block_job_is_cancelled(&s->common); 540 cnt = bdrv_get_dirty_count(s->dirty_bitmap); 541 } 542 } 543 544 if (cnt == 0 && should_complete) { 545 /* The dirty bitmap is not updated while operations are pending. 546 * If we're about to exit, wait for pending operations before 547 * calling bdrv_get_dirty_count(bs), or we may exit while the 548 * source has dirty data to copy! 549 * 550 * Note that I/O can be submitted by the guest while 551 * mirror_populate runs. 552 */ 553 trace_mirror_before_drain(s, cnt); 554 bdrv_drain(bs); 555 cnt = bdrv_get_dirty_count(s->dirty_bitmap); 556 } 557 558 ret = 0; 559 trace_mirror_before_sleep(s, cnt, s->synced, delay_ns); 560 if (!s->synced) { 561 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); 562 if (block_job_is_cancelled(&s->common)) { 563 break; 564 } 565 } else if (!should_complete) { 566 delay_ns = (s->in_flight == 0 && cnt == 0 ? SLICE_TIME : 0); 567 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); 568 } else if (cnt == 0) { 569 /* The two disks are in sync. Exit and report successful 570 * completion. 571 */ 572 assert(QLIST_EMPTY(&bs->tracked_requests)); 573 s->common.cancelled = false; 574 break; 575 } 576 last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 577 } 578 579 immediate_exit: 580 if (s->in_flight > 0) { 581 /* We get here only if something went wrong. Either the job failed, 582 * or it was cancelled prematurely so that we do not guarantee that 583 * the target is a copy of the source. 584 */ 585 assert(ret < 0 || (!s->synced && block_job_is_cancelled(&s->common))); 586 mirror_drain(s); 587 } 588 589 assert(s->in_flight == 0); 590 qemu_vfree(s->buf); 591 g_free(s->cow_bitmap); 592 g_free(s->in_flight_bitmap); 593 bdrv_release_dirty_bitmap(bs, s->dirty_bitmap); 594 bdrv_iostatus_disable(s->target); 595 596 data = g_malloc(sizeof(*data)); 597 data->ret = ret; 598 block_job_defer_to_main_loop(&s->common, mirror_exit, data); 599 } 600 601 static void mirror_set_speed(BlockJob *job, int64_t speed, Error **errp) 602 { 603 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 604 605 if (speed < 0) { 606 error_setg(errp, QERR_INVALID_PARAMETER, "speed"); 607 return; 608 } 609 ratelimit_set_speed(&s->limit, speed / BDRV_SECTOR_SIZE, SLICE_TIME); 610 } 611 612 static void mirror_iostatus_reset(BlockJob *job) 613 { 614 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 615 616 bdrv_iostatus_reset(s->target); 617 } 618 619 static void mirror_complete(BlockJob *job, Error **errp) 620 { 621 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 622 Error *local_err = NULL; 623 int ret; 624 625 ret = bdrv_open_backing_file(s->target, NULL, &local_err); 626 if (ret < 0) { 627 error_propagate(errp, local_err); 628 return; 629 } 630 if (!s->synced) { 631 error_setg(errp, QERR_BLOCK_JOB_NOT_READY, 632 bdrv_get_device_name(job->bs)); 633 return; 634 } 635 636 /* check the target bs is not blocked and block all operations on it */ 637 if (s->replaces) { 638 AioContext *replace_aio_context; 639 640 s->to_replace = check_to_replace_node(s->replaces, &local_err); 641 if (!s->to_replace) { 642 error_propagate(errp, local_err); 643 return; 644 } 645 646 replace_aio_context = bdrv_get_aio_context(s->to_replace); 647 aio_context_acquire(replace_aio_context); 648 649 error_setg(&s->replace_blocker, 650 "block device is in use by block-job-complete"); 651 bdrv_op_block_all(s->to_replace, s->replace_blocker); 652 bdrv_ref(s->to_replace); 653 654 aio_context_release(replace_aio_context); 655 } 656 657 s->should_complete = true; 658 block_job_enter(&s->common); 659 } 660 661 static const BlockJobDriver mirror_job_driver = { 662 .instance_size = sizeof(MirrorBlockJob), 663 .job_type = BLOCK_JOB_TYPE_MIRROR, 664 .set_speed = mirror_set_speed, 665 .iostatus_reset= mirror_iostatus_reset, 666 .complete = mirror_complete, 667 }; 668 669 static const BlockJobDriver commit_active_job_driver = { 670 .instance_size = sizeof(MirrorBlockJob), 671 .job_type = BLOCK_JOB_TYPE_COMMIT, 672 .set_speed = mirror_set_speed, 673 .iostatus_reset 674 = mirror_iostatus_reset, 675 .complete = mirror_complete, 676 }; 677 678 static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target, 679 const char *replaces, 680 int64_t speed, uint32_t granularity, 681 int64_t buf_size, 682 BlockdevOnError on_source_error, 683 BlockdevOnError on_target_error, 684 bool unmap, 685 BlockCompletionFunc *cb, 686 void *opaque, Error **errp, 687 const BlockJobDriver *driver, 688 bool is_none_mode, BlockDriverState *base) 689 { 690 MirrorBlockJob *s; 691 692 if (granularity == 0) { 693 granularity = bdrv_get_default_bitmap_granularity(target); 694 } 695 696 assert ((granularity & (granularity - 1)) == 0); 697 698 if ((on_source_error == BLOCKDEV_ON_ERROR_STOP || 699 on_source_error == BLOCKDEV_ON_ERROR_ENOSPC) && 700 !bdrv_iostatus_is_enabled(bs)) { 701 error_setg(errp, QERR_INVALID_PARAMETER, "on-source-error"); 702 return; 703 } 704 705 if (buf_size < 0) { 706 error_setg(errp, "Invalid parameter 'buf-size'"); 707 return; 708 } 709 710 if (buf_size == 0) { 711 buf_size = DEFAULT_MIRROR_BUF_SIZE; 712 } 713 714 s = block_job_create(driver, bs, speed, cb, opaque, errp); 715 if (!s) { 716 return; 717 } 718 719 s->replaces = g_strdup(replaces); 720 s->on_source_error = on_source_error; 721 s->on_target_error = on_target_error; 722 s->target = target; 723 s->is_none_mode = is_none_mode; 724 s->base = base; 725 s->granularity = granularity; 726 s->buf_size = ROUND_UP(buf_size, granularity); 727 s->unmap = unmap; 728 729 s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp); 730 if (!s->dirty_bitmap) { 731 g_free(s->replaces); 732 block_job_release(bs); 733 return; 734 } 735 bdrv_set_enable_write_cache(s->target, true); 736 bdrv_set_on_error(s->target, on_target_error, on_target_error); 737 bdrv_iostatus_enable(s->target); 738 s->common.co = qemu_coroutine_create(mirror_run); 739 trace_mirror_start(bs, s, s->common.co, opaque); 740 qemu_coroutine_enter(s->common.co, s); 741 } 742 743 void mirror_start(BlockDriverState *bs, BlockDriverState *target, 744 const char *replaces, 745 int64_t speed, uint32_t granularity, int64_t buf_size, 746 MirrorSyncMode mode, BlockdevOnError on_source_error, 747 BlockdevOnError on_target_error, 748 bool unmap, 749 BlockCompletionFunc *cb, 750 void *opaque, Error **errp) 751 { 752 bool is_none_mode; 753 BlockDriverState *base; 754 755 if (mode == MIRROR_SYNC_MODE_INCREMENTAL) { 756 error_setg(errp, "Sync mode 'incremental' not supported"); 757 return; 758 } 759 is_none_mode = mode == MIRROR_SYNC_MODE_NONE; 760 base = mode == MIRROR_SYNC_MODE_TOP ? bs->backing_hd : NULL; 761 mirror_start_job(bs, target, replaces, 762 speed, granularity, buf_size, 763 on_source_error, on_target_error, unmap, cb, opaque, errp, 764 &mirror_job_driver, is_none_mode, base); 765 } 766 767 void commit_active_start(BlockDriverState *bs, BlockDriverState *base, 768 int64_t speed, 769 BlockdevOnError on_error, 770 BlockCompletionFunc *cb, 771 void *opaque, Error **errp) 772 { 773 int64_t length, base_length; 774 int orig_base_flags; 775 int ret; 776 Error *local_err = NULL; 777 778 orig_base_flags = bdrv_get_flags(base); 779 780 if (bdrv_reopen(base, bs->open_flags, errp)) { 781 return; 782 } 783 784 length = bdrv_getlength(bs); 785 if (length < 0) { 786 error_setg_errno(errp, -length, 787 "Unable to determine length of %s", bs->filename); 788 goto error_restore_flags; 789 } 790 791 base_length = bdrv_getlength(base); 792 if (base_length < 0) { 793 error_setg_errno(errp, -base_length, 794 "Unable to determine length of %s", base->filename); 795 goto error_restore_flags; 796 } 797 798 if (length > base_length) { 799 ret = bdrv_truncate(base, length); 800 if (ret < 0) { 801 error_setg_errno(errp, -ret, 802 "Top image %s is larger than base image %s, and " 803 "resize of base image failed", 804 bs->filename, base->filename); 805 goto error_restore_flags; 806 } 807 } 808 809 bdrv_ref(base); 810 mirror_start_job(bs, base, NULL, speed, 0, 0, 811 on_error, on_error, false, cb, opaque, &local_err, 812 &commit_active_job_driver, false, base); 813 if (local_err) { 814 error_propagate(errp, local_err); 815 goto error_restore_flags; 816 } 817 818 return; 819 820 error_restore_flags: 821 /* ignore error and errp for bdrv_reopen, because we want to propagate 822 * the original error */ 823 bdrv_reopen(base, orig_base_flags, NULL); 824 return; 825 } 826