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 bool waiting_for_io; 64 } MirrorBlockJob; 65 66 typedef struct MirrorOp { 67 MirrorBlockJob *s; 68 QEMUIOVector qiov; 69 int64_t sector_num; 70 int nb_sectors; 71 } MirrorOp; 72 73 static BlockErrorAction mirror_error_action(MirrorBlockJob *s, bool read, 74 int error) 75 { 76 s->synced = false; 77 if (read) { 78 return block_job_error_action(&s->common, s->common.bs, 79 s->on_source_error, true, error); 80 } else { 81 return block_job_error_action(&s->common, s->target, 82 s->on_target_error, false, error); 83 } 84 } 85 86 static void mirror_iteration_done(MirrorOp *op, int ret) 87 { 88 MirrorBlockJob *s = op->s; 89 struct iovec *iov; 90 int64_t chunk_num; 91 int i, nb_chunks, sectors_per_chunk; 92 93 trace_mirror_iteration_done(s, op->sector_num, op->nb_sectors, ret); 94 95 s->in_flight--; 96 s->sectors_in_flight -= op->nb_sectors; 97 iov = op->qiov.iov; 98 for (i = 0; i < op->qiov.niov; i++) { 99 MirrorBuffer *buf = (MirrorBuffer *) iov[i].iov_base; 100 QSIMPLEQ_INSERT_TAIL(&s->buf_free, buf, next); 101 s->buf_free_count++; 102 } 103 104 sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; 105 chunk_num = op->sector_num / sectors_per_chunk; 106 nb_chunks = op->nb_sectors / sectors_per_chunk; 107 bitmap_clear(s->in_flight_bitmap, chunk_num, nb_chunks); 108 if (ret >= 0) { 109 if (s->cow_bitmap) { 110 bitmap_set(s->cow_bitmap, chunk_num, nb_chunks); 111 } 112 s->common.offset += (uint64_t)op->nb_sectors * BDRV_SECTOR_SIZE; 113 } 114 115 qemu_iovec_destroy(&op->qiov); 116 g_free(op); 117 118 if (s->waiting_for_io) { 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 BlockErrorAction action; 129 130 bdrv_set_dirty_bitmap(s->dirty_bitmap, op->sector_num, op->nb_sectors); 131 action = mirror_error_action(s, false, -ret); 132 if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) { 133 s->ret = ret; 134 } 135 } 136 mirror_iteration_done(op, ret); 137 } 138 139 static void mirror_read_complete(void *opaque, int ret) 140 { 141 MirrorOp *op = opaque; 142 MirrorBlockJob *s = op->s; 143 if (ret < 0) { 144 BlockErrorAction action; 145 146 bdrv_set_dirty_bitmap(s->dirty_bitmap, op->sector_num, op->nb_sectors); 147 action = mirror_error_action(s, true, -ret); 148 if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) { 149 s->ret = ret; 150 } 151 152 mirror_iteration_done(op, ret); 153 return; 154 } 155 bdrv_aio_writev(s->target, op->sector_num, &op->qiov, op->nb_sectors, 156 mirror_write_complete, op); 157 } 158 159 static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) 160 { 161 BlockDriverState *source = s->common.bs; 162 int nb_sectors, sectors_per_chunk, nb_chunks; 163 int64_t end, sector_num, next_chunk, next_sector, hbitmap_next_sector; 164 uint64_t delay_ns = 0; 165 MirrorOp *op; 166 int pnum; 167 int64_t ret; 168 169 s->sector_num = hbitmap_iter_next(&s->hbi); 170 if (s->sector_num < 0) { 171 bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi); 172 s->sector_num = hbitmap_iter_next(&s->hbi); 173 trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap)); 174 assert(s->sector_num >= 0); 175 } 176 177 hbitmap_next_sector = s->sector_num; 178 sector_num = s->sector_num; 179 sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; 180 end = s->bdev_length / BDRV_SECTOR_SIZE; 181 182 /* Extend the QEMUIOVector to include all adjacent blocks that will 183 * be copied in this operation. 184 * 185 * We have to do this if we have no backing file yet in the destination, 186 * and the cluster size is very large. Then we need to do COW ourselves. 187 * The first time a cluster is copied, copy it entirely. Note that, 188 * because both the granularity and the cluster size are powers of two, 189 * the number of sectors to copy cannot exceed one cluster. 190 * 191 * We also want to extend the QEMUIOVector to include more adjacent 192 * dirty blocks if possible, to limit the number of I/O operations and 193 * run efficiently even with a small granularity. 194 */ 195 nb_chunks = 0; 196 nb_sectors = 0; 197 next_sector = sector_num; 198 next_chunk = sector_num / sectors_per_chunk; 199 200 /* Wait for I/O to this cluster (from a previous iteration) to be done. */ 201 while (test_bit(next_chunk, s->in_flight_bitmap)) { 202 trace_mirror_yield_in_flight(s, sector_num, s->in_flight); 203 s->waiting_for_io = true; 204 qemu_coroutine_yield(); 205 s->waiting_for_io = false; 206 } 207 208 do { 209 int added_sectors, added_chunks; 210 211 if (!bdrv_get_dirty(source, s->dirty_bitmap, next_sector) || 212 test_bit(next_chunk, s->in_flight_bitmap)) { 213 assert(nb_sectors > 0); 214 break; 215 } 216 217 added_sectors = sectors_per_chunk; 218 if (s->cow_bitmap && !test_bit(next_chunk, s->cow_bitmap)) { 219 bdrv_round_to_clusters(s->target, 220 next_sector, added_sectors, 221 &next_sector, &added_sectors); 222 223 /* On the first iteration, the rounding may make us copy 224 * sectors before the first dirty one. 225 */ 226 if (next_sector < sector_num) { 227 assert(nb_sectors == 0); 228 sector_num = next_sector; 229 next_chunk = next_sector / sectors_per_chunk; 230 } 231 } 232 233 added_sectors = MIN(added_sectors, end - (sector_num + nb_sectors)); 234 added_chunks = (added_sectors + sectors_per_chunk - 1) / sectors_per_chunk; 235 236 /* When doing COW, it may happen that there is not enough space for 237 * a full cluster. Wait if that is the case. 238 */ 239 while (nb_chunks == 0 && s->buf_free_count < added_chunks) { 240 trace_mirror_yield_buf_busy(s, nb_chunks, s->in_flight); 241 s->waiting_for_io = true; 242 qemu_coroutine_yield(); 243 s->waiting_for_io = false; 244 } 245 if (s->buf_free_count < nb_chunks + added_chunks) { 246 trace_mirror_break_buf_busy(s, nb_chunks, s->in_flight); 247 break; 248 } 249 if (IOV_MAX < nb_chunks + added_chunks) { 250 trace_mirror_break_iov_max(s, nb_chunks, added_chunks); 251 break; 252 } 253 254 /* We have enough free space to copy these sectors. */ 255 bitmap_set(s->in_flight_bitmap, next_chunk, added_chunks); 256 257 nb_sectors += added_sectors; 258 nb_chunks += added_chunks; 259 next_sector += added_sectors; 260 next_chunk += added_chunks; 261 if (!s->synced && s->common.speed) { 262 delay_ns = ratelimit_calculate_delay(&s->limit, added_sectors); 263 } 264 } while (delay_ns == 0 && next_sector < end); 265 266 /* Allocate a MirrorOp that is used as an AIO callback. */ 267 op = g_new(MirrorOp, 1); 268 op->s = s; 269 op->sector_num = sector_num; 270 op->nb_sectors = nb_sectors; 271 272 /* Now make a QEMUIOVector taking enough granularity-sized chunks 273 * from s->buf_free. 274 */ 275 qemu_iovec_init(&op->qiov, nb_chunks); 276 next_sector = sector_num; 277 while (nb_chunks-- > 0) { 278 MirrorBuffer *buf = QSIMPLEQ_FIRST(&s->buf_free); 279 size_t remaining = (nb_sectors * BDRV_SECTOR_SIZE) - op->qiov.size; 280 281 QSIMPLEQ_REMOVE_HEAD(&s->buf_free, next); 282 s->buf_free_count--; 283 qemu_iovec_add(&op->qiov, buf, MIN(s->granularity, remaining)); 284 285 /* Advance the HBitmapIter in parallel, so that we do not examine 286 * the same sector twice. 287 */ 288 if (next_sector > hbitmap_next_sector 289 && bdrv_get_dirty(source, s->dirty_bitmap, next_sector)) { 290 hbitmap_next_sector = hbitmap_iter_next(&s->hbi); 291 } 292 293 next_sector += sectors_per_chunk; 294 } 295 296 bdrv_reset_dirty_bitmap(s->dirty_bitmap, sector_num, nb_sectors); 297 298 /* Copy the dirty cluster. */ 299 s->in_flight++; 300 s->sectors_in_flight += nb_sectors; 301 trace_mirror_one_iteration(s, sector_num, nb_sectors); 302 303 ret = bdrv_get_block_status_above(source, NULL, sector_num, 304 nb_sectors, &pnum); 305 if (ret < 0 || pnum < nb_sectors || 306 (ret & BDRV_BLOCK_DATA && !(ret & BDRV_BLOCK_ZERO))) { 307 bdrv_aio_readv(source, sector_num, &op->qiov, nb_sectors, 308 mirror_read_complete, op); 309 } else if (ret & BDRV_BLOCK_ZERO) { 310 bdrv_aio_write_zeroes(s->target, sector_num, op->nb_sectors, 311 s->unmap ? BDRV_REQ_MAY_UNMAP : 0, 312 mirror_write_complete, op); 313 } else { 314 assert(!(ret & BDRV_BLOCK_DATA)); 315 bdrv_aio_discard(s->target, sector_num, op->nb_sectors, 316 mirror_write_complete, op); 317 } 318 return delay_ns; 319 } 320 321 static void mirror_free_init(MirrorBlockJob *s) 322 { 323 int granularity = s->granularity; 324 size_t buf_size = s->buf_size; 325 uint8_t *buf = s->buf; 326 327 assert(s->buf_free_count == 0); 328 QSIMPLEQ_INIT(&s->buf_free); 329 while (buf_size != 0) { 330 MirrorBuffer *cur = (MirrorBuffer *)buf; 331 QSIMPLEQ_INSERT_TAIL(&s->buf_free, cur, next); 332 s->buf_free_count++; 333 buf_size -= granularity; 334 buf += granularity; 335 } 336 } 337 338 static void mirror_drain(MirrorBlockJob *s) 339 { 340 while (s->in_flight > 0) { 341 s->waiting_for_io = true; 342 qemu_coroutine_yield(); 343 s->waiting_for_io = false; 344 } 345 } 346 347 typedef struct { 348 int ret; 349 } MirrorExitData; 350 351 static void mirror_exit(BlockJob *job, void *opaque) 352 { 353 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 354 MirrorExitData *data = opaque; 355 AioContext *replace_aio_context = NULL; 356 357 if (s->to_replace) { 358 replace_aio_context = bdrv_get_aio_context(s->to_replace); 359 aio_context_acquire(replace_aio_context); 360 } 361 362 if (s->should_complete && data->ret == 0) { 363 BlockDriverState *to_replace = s->common.bs; 364 if (s->to_replace) { 365 to_replace = s->to_replace; 366 } 367 if (bdrv_get_flags(s->target) != bdrv_get_flags(to_replace)) { 368 bdrv_reopen(s->target, bdrv_get_flags(to_replace), NULL); 369 } 370 bdrv_swap(s->target, to_replace); 371 if (s->common.driver->job_type == BLOCK_JOB_TYPE_COMMIT) { 372 /* drop the bs loop chain formed by the swap: break the loop then 373 * trigger the unref from the top one */ 374 BlockDriverState *p = s->base->backing_hd; 375 bdrv_set_backing_hd(s->base, NULL); 376 bdrv_unref(p); 377 } 378 } 379 if (s->to_replace) { 380 bdrv_op_unblock_all(s->to_replace, s->replace_blocker); 381 error_free(s->replace_blocker); 382 bdrv_unref(s->to_replace); 383 } 384 if (replace_aio_context) { 385 aio_context_release(replace_aio_context); 386 } 387 g_free(s->replaces); 388 bdrv_unref(s->target); 389 block_job_completed(&s->common, data->ret); 390 g_free(data); 391 } 392 393 static void coroutine_fn mirror_run(void *opaque) 394 { 395 MirrorBlockJob *s = opaque; 396 MirrorExitData *data; 397 BlockDriverState *bs = s->common.bs; 398 int64_t sector_num, end, length; 399 uint64_t last_pause_ns; 400 BlockDriverInfo bdi; 401 char backing_filename[2]; /* we only need 2 characters because we are only 402 checking for a NULL string */ 403 int ret = 0; 404 int n; 405 406 if (block_job_is_cancelled(&s->common)) { 407 goto immediate_exit; 408 } 409 410 s->bdev_length = bdrv_getlength(bs); 411 if (s->bdev_length < 0) { 412 ret = s->bdev_length; 413 goto immediate_exit; 414 } else if (s->bdev_length == 0) { 415 /* Report BLOCK_JOB_READY and wait for complete. */ 416 block_job_event_ready(&s->common); 417 s->synced = true; 418 while (!block_job_is_cancelled(&s->common) && !s->should_complete) { 419 block_job_yield(&s->common); 420 } 421 s->common.cancelled = false; 422 goto immediate_exit; 423 } 424 425 length = DIV_ROUND_UP(s->bdev_length, s->granularity); 426 s->in_flight_bitmap = bitmap_new(length); 427 428 /* If we have no backing file yet in the destination, we cannot let 429 * the destination do COW. Instead, we copy sectors around the 430 * dirty data if needed. We need a bitmap to do that. 431 */ 432 bdrv_get_backing_filename(s->target, backing_filename, 433 sizeof(backing_filename)); 434 if (backing_filename[0] && !s->target->backing_hd) { 435 ret = bdrv_get_info(s->target, &bdi); 436 if (ret < 0) { 437 goto immediate_exit; 438 } 439 if (s->granularity < bdi.cluster_size) { 440 s->buf_size = MAX(s->buf_size, bdi.cluster_size); 441 s->cow_bitmap = bitmap_new(length); 442 } 443 } 444 445 end = s->bdev_length / BDRV_SECTOR_SIZE; 446 s->buf = qemu_try_blockalign(bs, s->buf_size); 447 if (s->buf == NULL) { 448 ret = -ENOMEM; 449 goto immediate_exit; 450 } 451 452 mirror_free_init(s); 453 454 last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 455 if (!s->is_none_mode) { 456 /* First part, loop on the sectors and initialize the dirty bitmap. */ 457 BlockDriverState *base = s->base; 458 bool mark_all_dirty = s->base == NULL && !bdrv_has_zero_init(s->target); 459 460 for (sector_num = 0; sector_num < end; ) { 461 /* Just to make sure we are not exceeding int limit. */ 462 int nb_sectors = MIN(INT_MAX >> BDRV_SECTOR_BITS, 463 end - sector_num); 464 int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 465 466 if (now - last_pause_ns > SLICE_TIME) { 467 last_pause_ns = now; 468 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, 0); 469 } 470 471 if (block_job_is_cancelled(&s->common)) { 472 goto immediate_exit; 473 } 474 475 ret = bdrv_is_allocated_above(bs, base, sector_num, nb_sectors, &n); 476 477 if (ret < 0) { 478 goto immediate_exit; 479 } 480 481 assert(n > 0); 482 if (ret == 1 || mark_all_dirty) { 483 bdrv_set_dirty_bitmap(s->dirty_bitmap, sector_num, n); 484 } 485 sector_num += n; 486 } 487 } 488 489 bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi); 490 for (;;) { 491 uint64_t delay_ns = 0; 492 int64_t cnt; 493 bool should_complete; 494 495 if (s->ret < 0) { 496 ret = s->ret; 497 goto immediate_exit; 498 } 499 500 cnt = bdrv_get_dirty_count(s->dirty_bitmap); 501 /* s->common.offset contains the number of bytes already processed so 502 * far, cnt is the number of dirty sectors remaining and 503 * s->sectors_in_flight is the number of sectors currently being 504 * processed; together those are the current total operation length */ 505 s->common.len = s->common.offset + 506 (cnt + s->sectors_in_flight) * BDRV_SECTOR_SIZE; 507 508 /* Note that even when no rate limit is applied we need to yield 509 * periodically with no pending I/O so that bdrv_drain_all() returns. 510 * We do so every SLICE_TIME nanoseconds, or when there is an error, 511 * or when the source is clean, whichever comes first. 512 */ 513 if (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - last_pause_ns < SLICE_TIME && 514 s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) { 515 if (s->in_flight == MAX_IN_FLIGHT || s->buf_free_count == 0 || 516 (cnt == 0 && s->in_flight > 0)) { 517 trace_mirror_yield(s, s->in_flight, s->buf_free_count, cnt); 518 s->waiting_for_io = true; 519 qemu_coroutine_yield(); 520 s->waiting_for_io = false; 521 continue; 522 } else if (cnt != 0) { 523 delay_ns = mirror_iteration(s); 524 } 525 } 526 527 should_complete = false; 528 if (s->in_flight == 0 && cnt == 0) { 529 trace_mirror_before_flush(s); 530 ret = bdrv_flush(s->target); 531 if (ret < 0) { 532 if (mirror_error_action(s, false, -ret) == 533 BLOCK_ERROR_ACTION_REPORT) { 534 goto immediate_exit; 535 } 536 } else { 537 /* We're out of the streaming phase. From now on, if the job 538 * is cancelled we will actually complete all pending I/O and 539 * report completion. This way, block-job-cancel will leave 540 * the target in a consistent state. 541 */ 542 if (!s->synced) { 543 block_job_event_ready(&s->common); 544 s->synced = true; 545 } 546 547 should_complete = s->should_complete || 548 block_job_is_cancelled(&s->common); 549 cnt = bdrv_get_dirty_count(s->dirty_bitmap); 550 } 551 } 552 553 if (cnt == 0 && should_complete) { 554 /* The dirty bitmap is not updated while operations are pending. 555 * If we're about to exit, wait for pending operations before 556 * calling bdrv_get_dirty_count(bs), or we may exit while the 557 * source has dirty data to copy! 558 * 559 * Note that I/O can be submitted by the guest while 560 * mirror_populate runs. 561 */ 562 trace_mirror_before_drain(s, cnt); 563 bdrv_drain(bs); 564 cnt = bdrv_get_dirty_count(s->dirty_bitmap); 565 } 566 567 ret = 0; 568 trace_mirror_before_sleep(s, cnt, s->synced, delay_ns); 569 if (!s->synced) { 570 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); 571 if (block_job_is_cancelled(&s->common)) { 572 break; 573 } 574 } else if (!should_complete) { 575 delay_ns = (s->in_flight == 0 && cnt == 0 ? SLICE_TIME : 0); 576 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); 577 } else if (cnt == 0) { 578 /* The two disks are in sync. Exit and report successful 579 * completion. 580 */ 581 assert(QLIST_EMPTY(&bs->tracked_requests)); 582 s->common.cancelled = false; 583 break; 584 } 585 last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 586 } 587 588 immediate_exit: 589 if (s->in_flight > 0) { 590 /* We get here only if something went wrong. Either the job failed, 591 * or it was cancelled prematurely so that we do not guarantee that 592 * the target is a copy of the source. 593 */ 594 assert(ret < 0 || (!s->synced && block_job_is_cancelled(&s->common))); 595 mirror_drain(s); 596 } 597 598 assert(s->in_flight == 0); 599 qemu_vfree(s->buf); 600 g_free(s->cow_bitmap); 601 g_free(s->in_flight_bitmap); 602 bdrv_release_dirty_bitmap(bs, s->dirty_bitmap); 603 bdrv_iostatus_disable(s->target); 604 605 data = g_malloc(sizeof(*data)); 606 data->ret = ret; 607 block_job_defer_to_main_loop(&s->common, mirror_exit, data); 608 } 609 610 static void mirror_set_speed(BlockJob *job, int64_t speed, Error **errp) 611 { 612 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 613 614 if (speed < 0) { 615 error_setg(errp, QERR_INVALID_PARAMETER, "speed"); 616 return; 617 } 618 ratelimit_set_speed(&s->limit, speed / BDRV_SECTOR_SIZE, SLICE_TIME); 619 } 620 621 static void mirror_iostatus_reset(BlockJob *job) 622 { 623 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 624 625 bdrv_iostatus_reset(s->target); 626 } 627 628 static void mirror_complete(BlockJob *job, Error **errp) 629 { 630 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 631 Error *local_err = NULL; 632 int ret; 633 634 ret = bdrv_open_backing_file(s->target, NULL, &local_err); 635 if (ret < 0) { 636 error_propagate(errp, local_err); 637 return; 638 } 639 if (!s->synced) { 640 error_setg(errp, QERR_BLOCK_JOB_NOT_READY, 641 bdrv_get_device_name(job->bs)); 642 return; 643 } 644 645 /* check the target bs is not blocked and block all operations on it */ 646 if (s->replaces) { 647 AioContext *replace_aio_context; 648 649 s->to_replace = bdrv_find_node(s->replaces); 650 if (!s->to_replace) { 651 error_setg(errp, "Node name '%s' not found", s->replaces); 652 return; 653 } 654 655 replace_aio_context = bdrv_get_aio_context(s->to_replace); 656 aio_context_acquire(replace_aio_context); 657 658 error_setg(&s->replace_blocker, 659 "block device is in use by block-job-complete"); 660 bdrv_op_block_all(s->to_replace, s->replace_blocker); 661 bdrv_ref(s->to_replace); 662 663 aio_context_release(replace_aio_context); 664 } 665 666 s->should_complete = true; 667 block_job_enter(&s->common); 668 } 669 670 static const BlockJobDriver mirror_job_driver = { 671 .instance_size = sizeof(MirrorBlockJob), 672 .job_type = BLOCK_JOB_TYPE_MIRROR, 673 .set_speed = mirror_set_speed, 674 .iostatus_reset= mirror_iostatus_reset, 675 .complete = mirror_complete, 676 }; 677 678 static const BlockJobDriver commit_active_job_driver = { 679 .instance_size = sizeof(MirrorBlockJob), 680 .job_type = BLOCK_JOB_TYPE_COMMIT, 681 .set_speed = mirror_set_speed, 682 .iostatus_reset 683 = mirror_iostatus_reset, 684 .complete = mirror_complete, 685 }; 686 687 static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target, 688 const char *replaces, 689 int64_t speed, uint32_t granularity, 690 int64_t buf_size, 691 BlockdevOnError on_source_error, 692 BlockdevOnError on_target_error, 693 bool unmap, 694 BlockCompletionFunc *cb, 695 void *opaque, Error **errp, 696 const BlockJobDriver *driver, 697 bool is_none_mode, BlockDriverState *base) 698 { 699 MirrorBlockJob *s; 700 701 if (granularity == 0) { 702 granularity = bdrv_get_default_bitmap_granularity(target); 703 } 704 705 assert ((granularity & (granularity - 1)) == 0); 706 707 if ((on_source_error == BLOCKDEV_ON_ERROR_STOP || 708 on_source_error == BLOCKDEV_ON_ERROR_ENOSPC) && 709 !bdrv_iostatus_is_enabled(bs)) { 710 error_setg(errp, QERR_INVALID_PARAMETER, "on-source-error"); 711 return; 712 } 713 714 if (buf_size < 0) { 715 error_setg(errp, "Invalid parameter 'buf-size'"); 716 return; 717 } 718 719 if (buf_size == 0) { 720 buf_size = DEFAULT_MIRROR_BUF_SIZE; 721 } 722 723 s = block_job_create(driver, bs, speed, cb, opaque, errp); 724 if (!s) { 725 return; 726 } 727 728 s->replaces = g_strdup(replaces); 729 s->on_source_error = on_source_error; 730 s->on_target_error = on_target_error; 731 s->target = target; 732 s->is_none_mode = is_none_mode; 733 s->base = base; 734 s->granularity = granularity; 735 s->buf_size = ROUND_UP(buf_size, granularity); 736 s->unmap = unmap; 737 738 s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp); 739 if (!s->dirty_bitmap) { 740 g_free(s->replaces); 741 block_job_release(bs); 742 return; 743 } 744 bdrv_set_enable_write_cache(s->target, true); 745 bdrv_set_on_error(s->target, on_target_error, on_target_error); 746 bdrv_iostatus_enable(s->target); 747 s->common.co = qemu_coroutine_create(mirror_run); 748 trace_mirror_start(bs, s, s->common.co, opaque); 749 qemu_coroutine_enter(s->common.co, s); 750 } 751 752 void mirror_start(BlockDriverState *bs, BlockDriverState *target, 753 const char *replaces, 754 int64_t speed, uint32_t granularity, int64_t buf_size, 755 MirrorSyncMode mode, BlockdevOnError on_source_error, 756 BlockdevOnError on_target_error, 757 bool unmap, 758 BlockCompletionFunc *cb, 759 void *opaque, Error **errp) 760 { 761 bool is_none_mode; 762 BlockDriverState *base; 763 764 if (mode == MIRROR_SYNC_MODE_INCREMENTAL) { 765 error_setg(errp, "Sync mode 'incremental' not supported"); 766 return; 767 } 768 is_none_mode = mode == MIRROR_SYNC_MODE_NONE; 769 base = mode == MIRROR_SYNC_MODE_TOP ? bs->backing_hd : NULL; 770 mirror_start_job(bs, target, replaces, 771 speed, granularity, buf_size, 772 on_source_error, on_target_error, unmap, cb, opaque, errp, 773 &mirror_job_driver, is_none_mode, base); 774 } 775 776 void commit_active_start(BlockDriverState *bs, BlockDriverState *base, 777 int64_t speed, 778 BlockdevOnError on_error, 779 BlockCompletionFunc *cb, 780 void *opaque, Error **errp) 781 { 782 int64_t length, base_length; 783 int orig_base_flags; 784 int ret; 785 Error *local_err = NULL; 786 787 orig_base_flags = bdrv_get_flags(base); 788 789 if (bdrv_reopen(base, bs->open_flags, errp)) { 790 return; 791 } 792 793 length = bdrv_getlength(bs); 794 if (length < 0) { 795 error_setg_errno(errp, -length, 796 "Unable to determine length of %s", bs->filename); 797 goto error_restore_flags; 798 } 799 800 base_length = bdrv_getlength(base); 801 if (base_length < 0) { 802 error_setg_errno(errp, -base_length, 803 "Unable to determine length of %s", base->filename); 804 goto error_restore_flags; 805 } 806 807 if (length > base_length) { 808 ret = bdrv_truncate(base, length); 809 if (ret < 0) { 810 error_setg_errno(errp, -ret, 811 "Top image %s is larger than base image %s, and " 812 "resize of base image failed", 813 bs->filename, base->filename); 814 goto error_restore_flags; 815 } 816 } 817 818 bdrv_ref(base); 819 mirror_start_job(bs, base, NULL, speed, 0, 0, 820 on_error, on_error, false, cb, opaque, &local_err, 821 &commit_active_job_driver, false, base); 822 if (local_err) { 823 error_propagate(errp, local_err); 824 goto error_restore_flags; 825 } 826 827 return; 828 829 error_restore_flags: 830 /* ignore error and errp for bdrv_reopen, because we want to propagate 831 * the original error */ 832 bdrv_reopen(base, orig_base_flags, NULL); 833 return; 834 } 835