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 "sysemu/block-backend.h" 18 #include "qapi/qmp/qerror.h" 19 #include "qemu/ratelimit.h" 20 #include "qemu/bitmap.h" 21 22 #define SLICE_TIME 100000000ULL /* ns */ 23 #define MAX_IN_FLIGHT 16 24 #define DEFAULT_MIRROR_BUF_SIZE (10 << 20) 25 26 /* The mirroring buffer is a list of granularity-sized chunks. 27 * Free chunks are organized in a list. 28 */ 29 typedef struct MirrorBuffer { 30 QSIMPLEQ_ENTRY(MirrorBuffer) next; 31 } MirrorBuffer; 32 33 typedef struct MirrorBlockJob { 34 BlockJob common; 35 RateLimit limit; 36 BlockDriverState *target; 37 BlockDriverState *base; 38 /* The name of the graph node to replace */ 39 char *replaces; 40 /* The BDS to replace */ 41 BlockDriverState *to_replace; 42 /* Used to block operations on the drive-mirror-replace target */ 43 Error *replace_blocker; 44 bool is_none_mode; 45 BlockdevOnError on_source_error, on_target_error; 46 bool synced; 47 bool should_complete; 48 int64_t sector_num; 49 int64_t granularity; 50 size_t buf_size; 51 int64_t bdev_length; 52 unsigned long *cow_bitmap; 53 BdrvDirtyBitmap *dirty_bitmap; 54 HBitmapIter hbi; 55 uint8_t *buf; 56 QSIMPLEQ_HEAD(, MirrorBuffer) buf_free; 57 int buf_free_count; 58 59 unsigned long *in_flight_bitmap; 60 int in_flight; 61 int sectors_in_flight; 62 int ret; 63 bool unmap; 64 bool waiting_for_io; 65 } MirrorBlockJob; 66 67 typedef struct MirrorOp { 68 MirrorBlockJob *s; 69 QEMUIOVector qiov; 70 int64_t sector_num; 71 int nb_sectors; 72 } MirrorOp; 73 74 static BlockErrorAction mirror_error_action(MirrorBlockJob *s, bool read, 75 int error) 76 { 77 s->synced = false; 78 if (read) { 79 return block_job_error_action(&s->common, s->common.bs, 80 s->on_source_error, true, error); 81 } else { 82 return block_job_error_action(&s->common, s->target, 83 s->on_target_error, false, error); 84 } 85 } 86 87 static void mirror_iteration_done(MirrorOp *op, int ret) 88 { 89 MirrorBlockJob *s = op->s; 90 struct iovec *iov; 91 int64_t chunk_num; 92 int i, nb_chunks, sectors_per_chunk; 93 94 trace_mirror_iteration_done(s, op->sector_num, op->nb_sectors, ret); 95 96 s->in_flight--; 97 s->sectors_in_flight -= op->nb_sectors; 98 iov = op->qiov.iov; 99 for (i = 0; i < op->qiov.niov; i++) { 100 MirrorBuffer *buf = (MirrorBuffer *) iov[i].iov_base; 101 QSIMPLEQ_INSERT_TAIL(&s->buf_free, buf, next); 102 s->buf_free_count++; 103 } 104 105 sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; 106 chunk_num = op->sector_num / sectors_per_chunk; 107 nb_chunks = op->nb_sectors / sectors_per_chunk; 108 bitmap_clear(s->in_flight_bitmap, chunk_num, nb_chunks); 109 if (ret >= 0) { 110 if (s->cow_bitmap) { 111 bitmap_set(s->cow_bitmap, chunk_num, nb_chunks); 112 } 113 s->common.offset += (uint64_t)op->nb_sectors * BDRV_SECTOR_SIZE; 114 } 115 116 qemu_iovec_destroy(&op->qiov); 117 g_free(op); 118 119 if (s->waiting_for_io) { 120 qemu_coroutine_enter(s->common.co, NULL); 121 } 122 } 123 124 static void mirror_write_complete(void *opaque, int ret) 125 { 126 MirrorOp *op = opaque; 127 MirrorBlockJob *s = op->s; 128 if (ret < 0) { 129 BlockErrorAction action; 130 131 bdrv_set_dirty_bitmap(s->dirty_bitmap, op->sector_num, op->nb_sectors); 132 action = mirror_error_action(s, false, -ret); 133 if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) { 134 s->ret = ret; 135 } 136 } 137 mirror_iteration_done(op, ret); 138 } 139 140 static void mirror_read_complete(void *opaque, int ret) 141 { 142 MirrorOp *op = opaque; 143 MirrorBlockJob *s = op->s; 144 if (ret < 0) { 145 BlockErrorAction action; 146 147 bdrv_set_dirty_bitmap(s->dirty_bitmap, op->sector_num, op->nb_sectors); 148 action = mirror_error_action(s, true, -ret); 149 if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) { 150 s->ret = ret; 151 } 152 153 mirror_iteration_done(op, ret); 154 return; 155 } 156 bdrv_aio_writev(s->target, op->sector_num, &op->qiov, op->nb_sectors, 157 mirror_write_complete, op); 158 } 159 160 static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) 161 { 162 BlockDriverState *source = s->common.bs; 163 int nb_sectors, sectors_per_chunk, nb_chunks; 164 int64_t end, sector_num, next_chunk, next_sector, hbitmap_next_sector; 165 uint64_t delay_ns = 0; 166 MirrorOp *op; 167 int pnum; 168 int64_t ret; 169 170 s->sector_num = hbitmap_iter_next(&s->hbi); 171 if (s->sector_num < 0) { 172 bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi); 173 s->sector_num = hbitmap_iter_next(&s->hbi); 174 trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap)); 175 assert(s->sector_num >= 0); 176 } 177 178 hbitmap_next_sector = s->sector_num; 179 sector_num = s->sector_num; 180 sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; 181 end = s->bdev_length / BDRV_SECTOR_SIZE; 182 183 /* Extend the QEMUIOVector to include all adjacent blocks that will 184 * be copied in this operation. 185 * 186 * We have to do this if we have no backing file yet in the destination, 187 * and the cluster size is very large. Then we need to do COW ourselves. 188 * The first time a cluster is copied, copy it entirely. Note that, 189 * because both the granularity and the cluster size are powers of two, 190 * the number of sectors to copy cannot exceed one cluster. 191 * 192 * We also want to extend the QEMUIOVector to include more adjacent 193 * dirty blocks if possible, to limit the number of I/O operations and 194 * run efficiently even with a small granularity. 195 */ 196 nb_chunks = 0; 197 nb_sectors = 0; 198 next_sector = sector_num; 199 next_chunk = sector_num / sectors_per_chunk; 200 201 /* Wait for I/O to this cluster (from a previous iteration) to be done. */ 202 while (test_bit(next_chunk, s->in_flight_bitmap)) { 203 trace_mirror_yield_in_flight(s, sector_num, s->in_flight); 204 s->waiting_for_io = true; 205 qemu_coroutine_yield(); 206 s->waiting_for_io = false; 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 s->waiting_for_io = true; 243 qemu_coroutine_yield(); 244 s->waiting_for_io = false; 245 } 246 if (s->buf_free_count < nb_chunks + added_chunks) { 247 trace_mirror_break_buf_busy(s, nb_chunks, s->in_flight); 248 break; 249 } 250 if (IOV_MAX < nb_chunks + added_chunks) { 251 trace_mirror_break_iov_max(s, nb_chunks, added_chunks); 252 break; 253 } 254 255 /* We have enough free space to copy these sectors. */ 256 bitmap_set(s->in_flight_bitmap, next_chunk, added_chunks); 257 258 nb_sectors += added_sectors; 259 nb_chunks += added_chunks; 260 next_sector += added_sectors; 261 next_chunk += added_chunks; 262 if (!s->synced && s->common.speed) { 263 delay_ns = ratelimit_calculate_delay(&s->limit, added_sectors); 264 } 265 } while (delay_ns == 0 && next_sector < end); 266 267 /* Allocate a MirrorOp that is used as an AIO callback. */ 268 op = g_new(MirrorOp, 1); 269 op->s = s; 270 op->sector_num = sector_num; 271 op->nb_sectors = nb_sectors; 272 273 /* Now make a QEMUIOVector taking enough granularity-sized chunks 274 * from s->buf_free. 275 */ 276 qemu_iovec_init(&op->qiov, nb_chunks); 277 next_sector = sector_num; 278 while (nb_chunks-- > 0) { 279 MirrorBuffer *buf = QSIMPLEQ_FIRST(&s->buf_free); 280 size_t remaining = (nb_sectors * BDRV_SECTOR_SIZE) - op->qiov.size; 281 282 QSIMPLEQ_REMOVE_HEAD(&s->buf_free, next); 283 s->buf_free_count--; 284 qemu_iovec_add(&op->qiov, buf, MIN(s->granularity, remaining)); 285 286 /* Advance the HBitmapIter in parallel, so that we do not examine 287 * the same sector twice. 288 */ 289 if (next_sector > hbitmap_next_sector 290 && bdrv_get_dirty(source, s->dirty_bitmap, next_sector)) { 291 hbitmap_next_sector = hbitmap_iter_next(&s->hbi); 292 } 293 294 next_sector += sectors_per_chunk; 295 } 296 297 bdrv_reset_dirty_bitmap(s->dirty_bitmap, sector_num, nb_sectors); 298 299 /* Copy the dirty cluster. */ 300 s->in_flight++; 301 s->sectors_in_flight += nb_sectors; 302 trace_mirror_one_iteration(s, sector_num, nb_sectors); 303 304 ret = bdrv_get_block_status_above(source, NULL, sector_num, 305 nb_sectors, &pnum); 306 if (ret < 0 || pnum < nb_sectors || 307 (ret & BDRV_BLOCK_DATA && !(ret & BDRV_BLOCK_ZERO))) { 308 bdrv_aio_readv(source, sector_num, &op->qiov, nb_sectors, 309 mirror_read_complete, op); 310 } else if (ret & BDRV_BLOCK_ZERO) { 311 bdrv_aio_write_zeroes(s->target, sector_num, op->nb_sectors, 312 s->unmap ? BDRV_REQ_MAY_UNMAP : 0, 313 mirror_write_complete, op); 314 } else { 315 assert(!(ret & BDRV_BLOCK_DATA)); 316 bdrv_aio_discard(s->target, sector_num, op->nb_sectors, 317 mirror_write_complete, op); 318 } 319 return delay_ns; 320 } 321 322 static void mirror_free_init(MirrorBlockJob *s) 323 { 324 int granularity = s->granularity; 325 size_t buf_size = s->buf_size; 326 uint8_t *buf = s->buf; 327 328 assert(s->buf_free_count == 0); 329 QSIMPLEQ_INIT(&s->buf_free); 330 while (buf_size != 0) { 331 MirrorBuffer *cur = (MirrorBuffer *)buf; 332 QSIMPLEQ_INSERT_TAIL(&s->buf_free, cur, next); 333 s->buf_free_count++; 334 buf_size -= granularity; 335 buf += granularity; 336 } 337 } 338 339 static void mirror_drain(MirrorBlockJob *s) 340 { 341 while (s->in_flight > 0) { 342 s->waiting_for_io = true; 343 qemu_coroutine_yield(); 344 s->waiting_for_io = false; 345 } 346 } 347 348 typedef struct { 349 int ret; 350 } MirrorExitData; 351 352 static void mirror_exit(BlockJob *job, void *opaque) 353 { 354 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 355 MirrorExitData *data = opaque; 356 AioContext *replace_aio_context = NULL; 357 BlockDriverState *src = s->common.bs; 358 359 /* Make sure that the source BDS doesn't go away before we called 360 * block_job_completed(). */ 361 bdrv_ref(src); 362 363 if (s->to_replace) { 364 replace_aio_context = bdrv_get_aio_context(s->to_replace); 365 aio_context_acquire(replace_aio_context); 366 } 367 368 if (s->should_complete && data->ret == 0) { 369 BlockDriverState *to_replace = s->common.bs; 370 if (s->to_replace) { 371 to_replace = s->to_replace; 372 } 373 if (bdrv_get_flags(s->target) != bdrv_get_flags(to_replace)) { 374 bdrv_reopen(s->target, bdrv_get_flags(to_replace), NULL); 375 } 376 bdrv_replace_in_backing_chain(to_replace, s->target); 377 } 378 if (s->to_replace) { 379 bdrv_op_unblock_all(s->to_replace, s->replace_blocker); 380 error_free(s->replace_blocker); 381 bdrv_unref(s->to_replace); 382 } 383 if (replace_aio_context) { 384 aio_context_release(replace_aio_context); 385 } 386 g_free(s->replaces); 387 bdrv_op_unblock_all(s->target, s->common.blocker); 388 bdrv_unref(s->target); 389 block_job_completed(&s->common, data->ret); 390 g_free(data); 391 bdrv_unref(src); 392 } 393 394 static void coroutine_fn mirror_run(void *opaque) 395 { 396 MirrorBlockJob *s = opaque; 397 MirrorExitData *data; 398 BlockDriverState *bs = s->common.bs; 399 int64_t sector_num, end, length; 400 uint64_t last_pause_ns; 401 BlockDriverInfo bdi; 402 char backing_filename[2]; /* we only need 2 characters because we are only 403 checking for a NULL string */ 404 int ret = 0; 405 int n; 406 407 if (block_job_is_cancelled(&s->common)) { 408 goto immediate_exit; 409 } 410 411 s->bdev_length = bdrv_getlength(bs); 412 if (s->bdev_length < 0) { 413 ret = s->bdev_length; 414 goto immediate_exit; 415 } else if (s->bdev_length == 0) { 416 /* Report BLOCK_JOB_READY and wait for complete. */ 417 block_job_event_ready(&s->common); 418 s->synced = true; 419 while (!block_job_is_cancelled(&s->common) && !s->should_complete) { 420 block_job_yield(&s->common); 421 } 422 s->common.cancelled = false; 423 goto immediate_exit; 424 } 425 426 length = DIV_ROUND_UP(s->bdev_length, s->granularity); 427 s->in_flight_bitmap = bitmap_new(length); 428 429 /* If we have no backing file yet in the destination, we cannot let 430 * the destination do COW. Instead, we copy sectors around the 431 * dirty data if needed. We need a bitmap to do that. 432 */ 433 bdrv_get_backing_filename(s->target, backing_filename, 434 sizeof(backing_filename)); 435 if (backing_filename[0] && !s->target->backing) { 436 ret = bdrv_get_info(s->target, &bdi); 437 if (ret < 0) { 438 goto immediate_exit; 439 } 440 if (s->granularity < bdi.cluster_size) { 441 s->buf_size = MAX(s->buf_size, bdi.cluster_size); 442 s->cow_bitmap = bitmap_new(length); 443 } 444 } 445 446 end = s->bdev_length / BDRV_SECTOR_SIZE; 447 s->buf = qemu_try_blockalign(bs, s->buf_size); 448 if (s->buf == NULL) { 449 ret = -ENOMEM; 450 goto immediate_exit; 451 } 452 453 mirror_free_init(s); 454 455 last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 456 if (!s->is_none_mode) { 457 /* First part, loop on the sectors and initialize the dirty bitmap. */ 458 BlockDriverState *base = s->base; 459 bool mark_all_dirty = s->base == NULL && !bdrv_has_zero_init(s->target); 460 461 for (sector_num = 0; sector_num < end; ) { 462 /* Just to make sure we are not exceeding int limit. */ 463 int nb_sectors = MIN(INT_MAX >> BDRV_SECTOR_BITS, 464 end - sector_num); 465 int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 466 467 if (now - last_pause_ns > SLICE_TIME) { 468 last_pause_ns = now; 469 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, 0); 470 } 471 472 if (block_job_is_cancelled(&s->common)) { 473 goto immediate_exit; 474 } 475 476 ret = bdrv_is_allocated_above(bs, base, sector_num, nb_sectors, &n); 477 478 if (ret < 0) { 479 goto immediate_exit; 480 } 481 482 assert(n > 0); 483 if (ret == 1 || mark_all_dirty) { 484 bdrv_set_dirty_bitmap(s->dirty_bitmap, sector_num, n); 485 } 486 sector_num += n; 487 } 488 } 489 490 bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi); 491 for (;;) { 492 uint64_t delay_ns = 0; 493 int64_t cnt; 494 bool should_complete; 495 496 if (s->ret < 0) { 497 ret = s->ret; 498 goto immediate_exit; 499 } 500 501 cnt = bdrv_get_dirty_count(s->dirty_bitmap); 502 /* s->common.offset contains the number of bytes already processed so 503 * far, cnt is the number of dirty sectors remaining and 504 * s->sectors_in_flight is the number of sectors currently being 505 * processed; together those are the current total operation length */ 506 s->common.len = s->common.offset + 507 (cnt + s->sectors_in_flight) * BDRV_SECTOR_SIZE; 508 509 /* Note that even when no rate limit is applied we need to yield 510 * periodically with no pending I/O so that bdrv_drain_all() returns. 511 * We do so every SLICE_TIME nanoseconds, or when there is an error, 512 * or when the source is clean, whichever comes first. 513 */ 514 if (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - last_pause_ns < SLICE_TIME && 515 s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) { 516 if (s->in_flight == MAX_IN_FLIGHT || s->buf_free_count == 0 || 517 (cnt == 0 && s->in_flight > 0)) { 518 trace_mirror_yield(s, s->in_flight, s->buf_free_count, cnt); 519 s->waiting_for_io = true; 520 qemu_coroutine_yield(); 521 s->waiting_for_io = false; 522 continue; 523 } else if (cnt != 0) { 524 delay_ns = mirror_iteration(s); 525 } 526 } 527 528 should_complete = false; 529 if (s->in_flight == 0 && cnt == 0) { 530 trace_mirror_before_flush(s); 531 ret = bdrv_flush(s->target); 532 if (ret < 0) { 533 if (mirror_error_action(s, false, -ret) == 534 BLOCK_ERROR_ACTION_REPORT) { 535 goto immediate_exit; 536 } 537 } else { 538 /* We're out of the streaming phase. From now on, if the job 539 * is cancelled we will actually complete all pending I/O and 540 * report completion. This way, block-job-cancel will leave 541 * the target in a consistent state. 542 */ 543 if (!s->synced) { 544 block_job_event_ready(&s->common); 545 s->synced = true; 546 } 547 548 should_complete = s->should_complete || 549 block_job_is_cancelled(&s->common); 550 cnt = bdrv_get_dirty_count(s->dirty_bitmap); 551 } 552 } 553 554 if (cnt == 0 && should_complete) { 555 /* The dirty bitmap is not updated while operations are pending. 556 * If we're about to exit, wait for pending operations before 557 * calling bdrv_get_dirty_count(bs), or we may exit while the 558 * source has dirty data to copy! 559 * 560 * Note that I/O can be submitted by the guest while 561 * mirror_populate runs. 562 */ 563 trace_mirror_before_drain(s, cnt); 564 bdrv_drain(bs); 565 cnt = bdrv_get_dirty_count(s->dirty_bitmap); 566 } 567 568 ret = 0; 569 trace_mirror_before_sleep(s, cnt, s->synced, delay_ns); 570 if (!s->synced) { 571 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); 572 if (block_job_is_cancelled(&s->common)) { 573 break; 574 } 575 } else if (!should_complete) { 576 delay_ns = (s->in_flight == 0 && cnt == 0 ? SLICE_TIME : 0); 577 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); 578 } else if (cnt == 0) { 579 /* The two disks are in sync. Exit and report successful 580 * completion. 581 */ 582 assert(QLIST_EMPTY(&bs->tracked_requests)); 583 s->common.cancelled = false; 584 break; 585 } 586 last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 587 } 588 589 immediate_exit: 590 if (s->in_flight > 0) { 591 /* We get here only if something went wrong. Either the job failed, 592 * or it was cancelled prematurely so that we do not guarantee that 593 * the target is a copy of the source. 594 */ 595 assert(ret < 0 || (!s->synced && block_job_is_cancelled(&s->common))); 596 mirror_drain(s); 597 } 598 599 assert(s->in_flight == 0); 600 qemu_vfree(s->buf); 601 g_free(s->cow_bitmap); 602 g_free(s->in_flight_bitmap); 603 bdrv_release_dirty_bitmap(bs, s->dirty_bitmap); 604 if (s->target->blk) { 605 blk_iostatus_disable(s->target->blk); 606 } 607 608 data = g_malloc(sizeof(*data)); 609 data->ret = ret; 610 block_job_defer_to_main_loop(&s->common, mirror_exit, data); 611 } 612 613 static void mirror_set_speed(BlockJob *job, int64_t speed, Error **errp) 614 { 615 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 616 617 if (speed < 0) { 618 error_setg(errp, QERR_INVALID_PARAMETER, "speed"); 619 return; 620 } 621 ratelimit_set_speed(&s->limit, speed / BDRV_SECTOR_SIZE, SLICE_TIME); 622 } 623 624 static void mirror_iostatus_reset(BlockJob *job) 625 { 626 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 627 628 if (s->target->blk) { 629 blk_iostatus_reset(s->target->blk); 630 } 631 } 632 633 static void mirror_complete(BlockJob *job, Error **errp) 634 { 635 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 636 Error *local_err = NULL; 637 int ret; 638 639 ret = bdrv_open_backing_file(s->target, NULL, &local_err); 640 if (ret < 0) { 641 error_propagate(errp, local_err); 642 return; 643 } 644 if (!s->synced) { 645 error_setg(errp, QERR_BLOCK_JOB_NOT_READY, job->id); 646 return; 647 } 648 649 /* check the target bs is not blocked and block all operations on it */ 650 if (s->replaces) { 651 AioContext *replace_aio_context; 652 653 s->to_replace = bdrv_find_node(s->replaces); 654 if (!s->to_replace) { 655 error_setg(errp, "Node name '%s' not found", s->replaces); 656 return; 657 } 658 659 replace_aio_context = bdrv_get_aio_context(s->to_replace); 660 aio_context_acquire(replace_aio_context); 661 662 error_setg(&s->replace_blocker, 663 "block device is in use by block-job-complete"); 664 bdrv_op_block_all(s->to_replace, s->replace_blocker); 665 bdrv_ref(s->to_replace); 666 667 aio_context_release(replace_aio_context); 668 } 669 670 s->should_complete = true; 671 block_job_enter(&s->common); 672 } 673 674 static const BlockJobDriver mirror_job_driver = { 675 .instance_size = sizeof(MirrorBlockJob), 676 .job_type = BLOCK_JOB_TYPE_MIRROR, 677 .set_speed = mirror_set_speed, 678 .iostatus_reset= mirror_iostatus_reset, 679 .complete = mirror_complete, 680 }; 681 682 static const BlockJobDriver commit_active_job_driver = { 683 .instance_size = sizeof(MirrorBlockJob), 684 .job_type = BLOCK_JOB_TYPE_COMMIT, 685 .set_speed = mirror_set_speed, 686 .iostatus_reset 687 = mirror_iostatus_reset, 688 .complete = mirror_complete, 689 }; 690 691 static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target, 692 const char *replaces, 693 int64_t speed, uint32_t granularity, 694 int64_t buf_size, 695 BlockdevOnError on_source_error, 696 BlockdevOnError on_target_error, 697 bool unmap, 698 BlockCompletionFunc *cb, 699 void *opaque, Error **errp, 700 const BlockJobDriver *driver, 701 bool is_none_mode, BlockDriverState *base) 702 { 703 MirrorBlockJob *s; 704 705 if (granularity == 0) { 706 granularity = bdrv_get_default_bitmap_granularity(target); 707 } 708 709 assert ((granularity & (granularity - 1)) == 0); 710 711 if ((on_source_error == BLOCKDEV_ON_ERROR_STOP || 712 on_source_error == BLOCKDEV_ON_ERROR_ENOSPC) && 713 (!bs->blk || !blk_iostatus_is_enabled(bs->blk))) { 714 error_setg(errp, QERR_INVALID_PARAMETER, "on-source-error"); 715 return; 716 } 717 718 if (buf_size < 0) { 719 error_setg(errp, "Invalid parameter 'buf-size'"); 720 return; 721 } 722 723 if (buf_size == 0) { 724 buf_size = DEFAULT_MIRROR_BUF_SIZE; 725 } 726 727 s = block_job_create(driver, bs, speed, cb, opaque, errp); 728 if (!s) { 729 return; 730 } 731 732 s->replaces = g_strdup(replaces); 733 s->on_source_error = on_source_error; 734 s->on_target_error = on_target_error; 735 s->target = target; 736 s->is_none_mode = is_none_mode; 737 s->base = base; 738 s->granularity = granularity; 739 s->buf_size = ROUND_UP(buf_size, granularity); 740 s->unmap = unmap; 741 742 s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp); 743 if (!s->dirty_bitmap) { 744 g_free(s->replaces); 745 block_job_unref(&s->common); 746 return; 747 } 748 749 bdrv_op_block_all(s->target, s->common.blocker); 750 751 bdrv_set_enable_write_cache(s->target, true); 752 if (s->target->blk) { 753 blk_set_on_error(s->target->blk, on_target_error, on_target_error); 754 blk_iostatus_enable(s->target->blk); 755 } 756 s->common.co = qemu_coroutine_create(mirror_run); 757 trace_mirror_start(bs, s, s->common.co, opaque); 758 qemu_coroutine_enter(s->common.co, s); 759 } 760 761 void mirror_start(BlockDriverState *bs, BlockDriverState *target, 762 const char *replaces, 763 int64_t speed, uint32_t granularity, int64_t buf_size, 764 MirrorSyncMode mode, BlockdevOnError on_source_error, 765 BlockdevOnError on_target_error, 766 bool unmap, 767 BlockCompletionFunc *cb, 768 void *opaque, Error **errp) 769 { 770 bool is_none_mode; 771 BlockDriverState *base; 772 773 if (mode == MIRROR_SYNC_MODE_INCREMENTAL) { 774 error_setg(errp, "Sync mode 'incremental' not supported"); 775 return; 776 } 777 is_none_mode = mode == MIRROR_SYNC_MODE_NONE; 778 base = mode == MIRROR_SYNC_MODE_TOP ? backing_bs(bs) : NULL; 779 mirror_start_job(bs, target, replaces, 780 speed, granularity, buf_size, 781 on_source_error, on_target_error, unmap, cb, opaque, errp, 782 &mirror_job_driver, is_none_mode, base); 783 } 784 785 void commit_active_start(BlockDriverState *bs, BlockDriverState *base, 786 int64_t speed, 787 BlockdevOnError on_error, 788 BlockCompletionFunc *cb, 789 void *opaque, Error **errp) 790 { 791 int64_t length, base_length; 792 int orig_base_flags; 793 int ret; 794 Error *local_err = NULL; 795 796 orig_base_flags = bdrv_get_flags(base); 797 798 if (bdrv_reopen(base, bs->open_flags, errp)) { 799 return; 800 } 801 802 length = bdrv_getlength(bs); 803 if (length < 0) { 804 error_setg_errno(errp, -length, 805 "Unable to determine length of %s", bs->filename); 806 goto error_restore_flags; 807 } 808 809 base_length = bdrv_getlength(base); 810 if (base_length < 0) { 811 error_setg_errno(errp, -base_length, 812 "Unable to determine length of %s", base->filename); 813 goto error_restore_flags; 814 } 815 816 if (length > base_length) { 817 ret = bdrv_truncate(base, length); 818 if (ret < 0) { 819 error_setg_errno(errp, -ret, 820 "Top image %s is larger than base image %s, and " 821 "resize of base image failed", 822 bs->filename, base->filename); 823 goto error_restore_flags; 824 } 825 } 826 827 bdrv_ref(base); 828 mirror_start_job(bs, base, NULL, speed, 0, 0, 829 on_error, on_error, false, cb, opaque, &local_err, 830 &commit_active_job_driver, false, base); 831 if (local_err) { 832 error_propagate(errp, local_err); 833 goto error_restore_flags; 834 } 835 836 return; 837 838 error_restore_flags: 839 /* ignore error and errp for bdrv_reopen, because we want to propagate 840 * the original error */ 841 bdrv_reopen(base, orig_base_flags, NULL); 842 return; 843 } 844