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 "qemu/osdep.h" 15 #include "trace.h" 16 #include "block/blockjob.h" 17 #include "block/block_int.h" 18 #include "sysemu/block-backend.h" 19 #include "qapi/qmp/qerror.h" 20 #include "qemu/ratelimit.h" 21 #include "qemu/bitmap.h" 22 #include "qemu/error-report.h" 23 24 #define SLICE_TIME 100000000ULL /* ns */ 25 #define MAX_IN_FLIGHT 16 26 #define DEFAULT_MIRROR_BUF_SIZE (10 << 20) 27 28 /* The mirroring buffer is a list of granularity-sized chunks. 29 * Free chunks are organized in a list. 30 */ 31 typedef struct MirrorBuffer { 32 QSIMPLEQ_ENTRY(MirrorBuffer) next; 33 } MirrorBuffer; 34 35 typedef struct MirrorBlockJob { 36 BlockJob common; 37 RateLimit limit; 38 BlockDriverState *target; 39 BlockDriverState *base; 40 /* The name of the graph node to replace */ 41 char *replaces; 42 /* The BDS to replace */ 43 BlockDriverState *to_replace; 44 /* Used to block operations on the drive-mirror-replace target */ 45 Error *replace_blocker; 46 bool is_none_mode; 47 BlockdevOnError on_source_error, on_target_error; 48 bool synced; 49 bool should_complete; 50 int64_t sector_num; 51 int64_t granularity; 52 size_t buf_size; 53 int64_t bdev_length; 54 unsigned long *cow_bitmap; 55 BdrvDirtyBitmap *dirty_bitmap; 56 HBitmapIter hbi; 57 uint8_t *buf; 58 QSIMPLEQ_HEAD(, MirrorBuffer) buf_free; 59 int buf_free_count; 60 61 unsigned long *in_flight_bitmap; 62 int in_flight; 63 int sectors_in_flight; 64 int ret; 65 bool unmap; 66 bool waiting_for_io; 67 } MirrorBlockJob; 68 69 typedef struct MirrorOp { 70 MirrorBlockJob *s; 71 QEMUIOVector qiov; 72 int64_t sector_num; 73 int nb_sectors; 74 } MirrorOp; 75 76 static BlockErrorAction mirror_error_action(MirrorBlockJob *s, bool read, 77 int error) 78 { 79 s->synced = false; 80 if (read) { 81 return block_job_error_action(&s->common, s->common.bs, 82 s->on_source_error, true, error); 83 } else { 84 return block_job_error_action(&s->common, s->target, 85 s->on_target_error, false, error); 86 } 87 } 88 89 static void mirror_iteration_done(MirrorOp *op, int ret) 90 { 91 MirrorBlockJob *s = op->s; 92 struct iovec *iov; 93 int64_t chunk_num; 94 int i, nb_chunks, sectors_per_chunk; 95 96 trace_mirror_iteration_done(s, op->sector_num, op->nb_sectors, ret); 97 98 s->in_flight--; 99 s->sectors_in_flight -= op->nb_sectors; 100 iov = op->qiov.iov; 101 for (i = 0; i < op->qiov.niov; i++) { 102 MirrorBuffer *buf = (MirrorBuffer *) iov[i].iov_base; 103 QSIMPLEQ_INSERT_TAIL(&s->buf_free, buf, next); 104 s->buf_free_count++; 105 } 106 107 sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; 108 chunk_num = op->sector_num / sectors_per_chunk; 109 nb_chunks = op->nb_sectors / sectors_per_chunk; 110 bitmap_clear(s->in_flight_bitmap, chunk_num, nb_chunks); 111 if (ret >= 0) { 112 if (s->cow_bitmap) { 113 bitmap_set(s->cow_bitmap, chunk_num, nb_chunks); 114 } 115 s->common.offset += (uint64_t)op->nb_sectors * BDRV_SECTOR_SIZE; 116 } 117 118 qemu_iovec_destroy(&op->qiov); 119 g_free(op); 120 121 if (s->waiting_for_io) { 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, max_iov; 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 BlockDriverState *file; 172 173 max_iov = MIN(source->bl.max_iov, s->target->bl.max_iov); 174 175 s->sector_num = hbitmap_iter_next(&s->hbi); 176 if (s->sector_num < 0) { 177 bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi); 178 s->sector_num = hbitmap_iter_next(&s->hbi); 179 trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap)); 180 assert(s->sector_num >= 0); 181 } 182 183 hbitmap_next_sector = s->sector_num; 184 sector_num = s->sector_num; 185 sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; 186 end = s->bdev_length / BDRV_SECTOR_SIZE; 187 188 /* Extend the QEMUIOVector to include all adjacent blocks that will 189 * be copied in this operation. 190 * 191 * We have to do this if we have no backing file yet in the destination, 192 * and the cluster size is very large. Then we need to do COW ourselves. 193 * The first time a cluster is copied, copy it entirely. Note that, 194 * because both the granularity and the cluster size are powers of two, 195 * the number of sectors to copy cannot exceed one cluster. 196 * 197 * We also want to extend the QEMUIOVector to include more adjacent 198 * dirty blocks if possible, to limit the number of I/O operations and 199 * run efficiently even with a small granularity. 200 */ 201 nb_chunks = 0; 202 nb_sectors = 0; 203 next_sector = sector_num; 204 next_chunk = sector_num / sectors_per_chunk; 205 206 /* Wait for I/O to this cluster (from a previous iteration) to be done. */ 207 while (test_bit(next_chunk, s->in_flight_bitmap)) { 208 trace_mirror_yield_in_flight(s, sector_num, s->in_flight); 209 s->waiting_for_io = true; 210 qemu_coroutine_yield(); 211 s->waiting_for_io = false; 212 } 213 214 do { 215 int added_sectors, added_chunks; 216 217 if (!bdrv_get_dirty(source, s->dirty_bitmap, next_sector) || 218 test_bit(next_chunk, s->in_flight_bitmap)) { 219 assert(nb_sectors > 0); 220 break; 221 } 222 223 added_sectors = sectors_per_chunk; 224 if (s->cow_bitmap && !test_bit(next_chunk, s->cow_bitmap)) { 225 bdrv_round_to_clusters(s->target, 226 next_sector, added_sectors, 227 &next_sector, &added_sectors); 228 229 /* On the first iteration, the rounding may make us copy 230 * sectors before the first dirty one. 231 */ 232 if (next_sector < sector_num) { 233 assert(nb_sectors == 0); 234 sector_num = next_sector; 235 next_chunk = next_sector / sectors_per_chunk; 236 } 237 } 238 239 added_sectors = MIN(added_sectors, end - (sector_num + nb_sectors)); 240 added_chunks = (added_sectors + sectors_per_chunk - 1) / sectors_per_chunk; 241 242 /* When doing COW, it may happen that there is not enough space for 243 * a full cluster. Wait if that is the case. 244 */ 245 while (nb_chunks == 0 && s->buf_free_count < added_chunks) { 246 trace_mirror_yield_buf_busy(s, nb_chunks, s->in_flight); 247 s->waiting_for_io = true; 248 qemu_coroutine_yield(); 249 s->waiting_for_io = false; 250 } 251 if (s->buf_free_count < nb_chunks + added_chunks) { 252 trace_mirror_break_buf_busy(s, nb_chunks, s->in_flight); 253 break; 254 } 255 if (max_iov < nb_chunks + added_chunks) { 256 trace_mirror_break_iov_max(s, nb_chunks, added_chunks); 257 break; 258 } 259 260 /* We have enough free space to copy these sectors. */ 261 bitmap_set(s->in_flight_bitmap, next_chunk, added_chunks); 262 263 nb_sectors += added_sectors; 264 nb_chunks += added_chunks; 265 next_sector += added_sectors; 266 next_chunk += added_chunks; 267 if (!s->synced && s->common.speed) { 268 delay_ns = ratelimit_calculate_delay(&s->limit, added_sectors); 269 } 270 } while (delay_ns == 0 && next_sector < end); 271 272 /* Allocate a MirrorOp that is used as an AIO callback. */ 273 op = g_new(MirrorOp, 1); 274 op->s = s; 275 op->sector_num = sector_num; 276 op->nb_sectors = nb_sectors; 277 278 /* Now make a QEMUIOVector taking enough granularity-sized chunks 279 * from s->buf_free. 280 */ 281 qemu_iovec_init(&op->qiov, nb_chunks); 282 next_sector = sector_num; 283 while (nb_chunks-- > 0) { 284 MirrorBuffer *buf = QSIMPLEQ_FIRST(&s->buf_free); 285 size_t remaining = (nb_sectors * BDRV_SECTOR_SIZE) - op->qiov.size; 286 287 QSIMPLEQ_REMOVE_HEAD(&s->buf_free, next); 288 s->buf_free_count--; 289 qemu_iovec_add(&op->qiov, buf, MIN(s->granularity, remaining)); 290 291 /* Advance the HBitmapIter in parallel, so that we do not examine 292 * the same sector twice. 293 */ 294 if (next_sector > hbitmap_next_sector 295 && bdrv_get_dirty(source, s->dirty_bitmap, next_sector)) { 296 hbitmap_next_sector = hbitmap_iter_next(&s->hbi); 297 } 298 299 next_sector += sectors_per_chunk; 300 } 301 302 bdrv_reset_dirty_bitmap(s->dirty_bitmap, sector_num, nb_sectors); 303 304 /* Copy the dirty cluster. */ 305 s->in_flight++; 306 s->sectors_in_flight += nb_sectors; 307 trace_mirror_one_iteration(s, sector_num, nb_sectors); 308 309 ret = bdrv_get_block_status_above(source, NULL, sector_num, 310 nb_sectors, &pnum, &file); 311 if (ret < 0 || pnum < nb_sectors || 312 (ret & BDRV_BLOCK_DATA && !(ret & BDRV_BLOCK_ZERO))) { 313 bdrv_aio_readv(source, sector_num, &op->qiov, nb_sectors, 314 mirror_read_complete, op); 315 } else if (ret & BDRV_BLOCK_ZERO) { 316 bdrv_aio_write_zeroes(s->target, sector_num, op->nb_sectors, 317 s->unmap ? BDRV_REQ_MAY_UNMAP : 0, 318 mirror_write_complete, op); 319 } else { 320 assert(!(ret & BDRV_BLOCK_DATA)); 321 bdrv_aio_discard(s->target, sector_num, op->nb_sectors, 322 mirror_write_complete, op); 323 } 324 return delay_ns; 325 } 326 327 static void mirror_free_init(MirrorBlockJob *s) 328 { 329 int granularity = s->granularity; 330 size_t buf_size = s->buf_size; 331 uint8_t *buf = s->buf; 332 333 assert(s->buf_free_count == 0); 334 QSIMPLEQ_INIT(&s->buf_free); 335 while (buf_size != 0) { 336 MirrorBuffer *cur = (MirrorBuffer *)buf; 337 QSIMPLEQ_INSERT_TAIL(&s->buf_free, cur, next); 338 s->buf_free_count++; 339 buf_size -= granularity; 340 buf += granularity; 341 } 342 } 343 344 static void mirror_drain(MirrorBlockJob *s) 345 { 346 while (s->in_flight > 0) { 347 s->waiting_for_io = true; 348 qemu_coroutine_yield(); 349 s->waiting_for_io = false; 350 } 351 } 352 353 typedef struct { 354 int ret; 355 } MirrorExitData; 356 357 static void mirror_exit(BlockJob *job, void *opaque) 358 { 359 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 360 MirrorExitData *data = opaque; 361 AioContext *replace_aio_context = NULL; 362 BlockDriverState *src = s->common.bs; 363 364 /* Make sure that the source BDS doesn't go away before we called 365 * block_job_completed(). */ 366 bdrv_ref(src); 367 368 if (s->to_replace) { 369 replace_aio_context = bdrv_get_aio_context(s->to_replace); 370 aio_context_acquire(replace_aio_context); 371 } 372 373 if (s->should_complete && data->ret == 0) { 374 BlockDriverState *to_replace = s->common.bs; 375 if (s->to_replace) { 376 to_replace = s->to_replace; 377 } 378 379 /* This was checked in mirror_start_job(), but meanwhile one of the 380 * nodes could have been newly attached to a BlockBackend. */ 381 if (to_replace->blk && s->target->blk) { 382 error_report("block job: Can't create node with two BlockBackends"); 383 data->ret = -EINVAL; 384 goto out; 385 } 386 387 if (bdrv_get_flags(s->target) != bdrv_get_flags(to_replace)) { 388 bdrv_reopen(s->target, bdrv_get_flags(to_replace), NULL); 389 } 390 bdrv_replace_in_backing_chain(to_replace, s->target); 391 } 392 393 out: 394 if (s->to_replace) { 395 bdrv_op_unblock_all(s->to_replace, s->replace_blocker); 396 error_free(s->replace_blocker); 397 bdrv_unref(s->to_replace); 398 } 399 if (replace_aio_context) { 400 aio_context_release(replace_aio_context); 401 } 402 g_free(s->replaces); 403 bdrv_op_unblock_all(s->target, s->common.blocker); 404 bdrv_unref(s->target); 405 block_job_completed(&s->common, data->ret); 406 g_free(data); 407 bdrv_drained_end(src); 408 bdrv_unref(src); 409 } 410 411 static void coroutine_fn mirror_run(void *opaque) 412 { 413 MirrorBlockJob *s = opaque; 414 MirrorExitData *data; 415 BlockDriverState *bs = s->common.bs; 416 int64_t sector_num, end, length; 417 uint64_t last_pause_ns; 418 BlockDriverInfo bdi; 419 char backing_filename[2]; /* we only need 2 characters because we are only 420 checking for a NULL string */ 421 int ret = 0; 422 int n; 423 424 if (block_job_is_cancelled(&s->common)) { 425 goto immediate_exit; 426 } 427 428 s->bdev_length = bdrv_getlength(bs); 429 if (s->bdev_length < 0) { 430 ret = s->bdev_length; 431 goto immediate_exit; 432 } else if (s->bdev_length == 0) { 433 /* Report BLOCK_JOB_READY and wait for complete. */ 434 block_job_event_ready(&s->common); 435 s->synced = true; 436 while (!block_job_is_cancelled(&s->common) && !s->should_complete) { 437 block_job_yield(&s->common); 438 } 439 s->common.cancelled = false; 440 goto immediate_exit; 441 } 442 443 length = DIV_ROUND_UP(s->bdev_length, s->granularity); 444 s->in_flight_bitmap = bitmap_new(length); 445 446 /* If we have no backing file yet in the destination, we cannot let 447 * the destination do COW. Instead, we copy sectors around the 448 * dirty data if needed. We need a bitmap to do that. 449 */ 450 bdrv_get_backing_filename(s->target, backing_filename, 451 sizeof(backing_filename)); 452 if (backing_filename[0] && !s->target->backing) { 453 ret = bdrv_get_info(s->target, &bdi); 454 if (ret < 0) { 455 goto immediate_exit; 456 } 457 if (s->granularity < bdi.cluster_size) { 458 s->buf_size = MAX(s->buf_size, bdi.cluster_size); 459 s->cow_bitmap = bitmap_new(length); 460 } 461 } 462 463 end = s->bdev_length / BDRV_SECTOR_SIZE; 464 s->buf = qemu_try_blockalign(bs, s->buf_size); 465 if (s->buf == NULL) { 466 ret = -ENOMEM; 467 goto immediate_exit; 468 } 469 470 mirror_free_init(s); 471 472 last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 473 if (!s->is_none_mode) { 474 /* First part, loop on the sectors and initialize the dirty bitmap. */ 475 BlockDriverState *base = s->base; 476 bool mark_all_dirty = s->base == NULL && !bdrv_has_zero_init(s->target); 477 478 for (sector_num = 0; sector_num < end; ) { 479 /* Just to make sure we are not exceeding int limit. */ 480 int nb_sectors = MIN(INT_MAX >> BDRV_SECTOR_BITS, 481 end - sector_num); 482 int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 483 484 if (now - last_pause_ns > SLICE_TIME) { 485 last_pause_ns = now; 486 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, 0); 487 } 488 489 if (block_job_is_cancelled(&s->common)) { 490 goto immediate_exit; 491 } 492 493 ret = bdrv_is_allocated_above(bs, base, sector_num, nb_sectors, &n); 494 495 if (ret < 0) { 496 goto immediate_exit; 497 } 498 499 assert(n > 0); 500 if (ret == 1 || mark_all_dirty) { 501 bdrv_set_dirty_bitmap(s->dirty_bitmap, sector_num, n); 502 } 503 sector_num += n; 504 } 505 } 506 507 bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi); 508 for (;;) { 509 uint64_t delay_ns = 0; 510 int64_t cnt; 511 bool should_complete; 512 513 if (s->ret < 0) { 514 ret = s->ret; 515 goto immediate_exit; 516 } 517 518 cnt = bdrv_get_dirty_count(s->dirty_bitmap); 519 /* s->common.offset contains the number of bytes already processed so 520 * far, cnt is the number of dirty sectors remaining and 521 * s->sectors_in_flight is the number of sectors currently being 522 * processed; together those are the current total operation length */ 523 s->common.len = s->common.offset + 524 (cnt + s->sectors_in_flight) * BDRV_SECTOR_SIZE; 525 526 /* Note that even when no rate limit is applied we need to yield 527 * periodically with no pending I/O so that bdrv_drain_all() returns. 528 * We do so every SLICE_TIME nanoseconds, or when there is an error, 529 * or when the source is clean, whichever comes first. 530 */ 531 if (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - last_pause_ns < SLICE_TIME && 532 s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) { 533 if (s->in_flight == MAX_IN_FLIGHT || s->buf_free_count == 0 || 534 (cnt == 0 && s->in_flight > 0)) { 535 trace_mirror_yield(s, s->in_flight, s->buf_free_count, cnt); 536 s->waiting_for_io = true; 537 qemu_coroutine_yield(); 538 s->waiting_for_io = false; 539 continue; 540 } else if (cnt != 0) { 541 delay_ns = mirror_iteration(s); 542 } 543 } 544 545 should_complete = false; 546 if (s->in_flight == 0 && cnt == 0) { 547 trace_mirror_before_flush(s); 548 ret = bdrv_flush(s->target); 549 if (ret < 0) { 550 if (mirror_error_action(s, false, -ret) == 551 BLOCK_ERROR_ACTION_REPORT) { 552 goto immediate_exit; 553 } 554 } else { 555 /* We're out of the streaming phase. From now on, if the job 556 * is cancelled we will actually complete all pending I/O and 557 * report completion. This way, block-job-cancel will leave 558 * the target in a consistent state. 559 */ 560 if (!s->synced) { 561 block_job_event_ready(&s->common); 562 s->synced = true; 563 } 564 565 should_complete = s->should_complete || 566 block_job_is_cancelled(&s->common); 567 cnt = bdrv_get_dirty_count(s->dirty_bitmap); 568 } 569 } 570 571 if (cnt == 0 && should_complete) { 572 /* The dirty bitmap is not updated while operations are pending. 573 * If we're about to exit, wait for pending operations before 574 * calling bdrv_get_dirty_count(bs), or we may exit while the 575 * source has dirty data to copy! 576 * 577 * Note that I/O can be submitted by the guest while 578 * mirror_populate runs. 579 */ 580 trace_mirror_before_drain(s, cnt); 581 bdrv_drain(bs); 582 cnt = bdrv_get_dirty_count(s->dirty_bitmap); 583 } 584 585 ret = 0; 586 trace_mirror_before_sleep(s, cnt, s->synced, delay_ns); 587 if (!s->synced) { 588 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); 589 if (block_job_is_cancelled(&s->common)) { 590 break; 591 } 592 } else if (!should_complete) { 593 delay_ns = (s->in_flight == 0 && cnt == 0 ? SLICE_TIME : 0); 594 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); 595 } else if (cnt == 0) { 596 /* The two disks are in sync. Exit and report successful 597 * completion. 598 */ 599 assert(QLIST_EMPTY(&bs->tracked_requests)); 600 s->common.cancelled = false; 601 break; 602 } 603 last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 604 } 605 606 immediate_exit: 607 if (s->in_flight > 0) { 608 /* We get here only if something went wrong. Either the job failed, 609 * or it was cancelled prematurely so that we do not guarantee that 610 * the target is a copy of the source. 611 */ 612 assert(ret < 0 || (!s->synced && block_job_is_cancelled(&s->common))); 613 mirror_drain(s); 614 } 615 616 assert(s->in_flight == 0); 617 qemu_vfree(s->buf); 618 g_free(s->cow_bitmap); 619 g_free(s->in_flight_bitmap); 620 bdrv_release_dirty_bitmap(bs, s->dirty_bitmap); 621 if (s->target->blk) { 622 blk_iostatus_disable(s->target->blk); 623 } 624 625 data = g_malloc(sizeof(*data)); 626 data->ret = ret; 627 /* Before we switch to target in mirror_exit, make sure data doesn't 628 * change. */ 629 bdrv_drained_begin(s->common.bs); 630 block_job_defer_to_main_loop(&s->common, mirror_exit, data); 631 } 632 633 static void mirror_set_speed(BlockJob *job, int64_t speed, Error **errp) 634 { 635 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 636 637 if (speed < 0) { 638 error_setg(errp, QERR_INVALID_PARAMETER, "speed"); 639 return; 640 } 641 ratelimit_set_speed(&s->limit, speed / BDRV_SECTOR_SIZE, SLICE_TIME); 642 } 643 644 static void mirror_iostatus_reset(BlockJob *job) 645 { 646 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 647 648 if (s->target->blk) { 649 blk_iostatus_reset(s->target->blk); 650 } 651 } 652 653 static void mirror_complete(BlockJob *job, Error **errp) 654 { 655 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 656 Error *local_err = NULL; 657 int ret; 658 659 ret = bdrv_open_backing_file(s->target, NULL, "backing", &local_err); 660 if (ret < 0) { 661 error_propagate(errp, local_err); 662 return; 663 } 664 if (!s->synced) { 665 error_setg(errp, QERR_BLOCK_JOB_NOT_READY, job->id); 666 return; 667 } 668 669 /* check the target bs is not blocked and block all operations on it */ 670 if (s->replaces) { 671 AioContext *replace_aio_context; 672 673 s->to_replace = bdrv_find_node(s->replaces); 674 if (!s->to_replace) { 675 error_setg(errp, "Node name '%s' not found", s->replaces); 676 return; 677 } 678 679 replace_aio_context = bdrv_get_aio_context(s->to_replace); 680 aio_context_acquire(replace_aio_context); 681 682 error_setg(&s->replace_blocker, 683 "block device is in use by block-job-complete"); 684 bdrv_op_block_all(s->to_replace, s->replace_blocker); 685 bdrv_ref(s->to_replace); 686 687 aio_context_release(replace_aio_context); 688 } 689 690 s->should_complete = true; 691 block_job_enter(&s->common); 692 } 693 694 static const BlockJobDriver mirror_job_driver = { 695 .instance_size = sizeof(MirrorBlockJob), 696 .job_type = BLOCK_JOB_TYPE_MIRROR, 697 .set_speed = mirror_set_speed, 698 .iostatus_reset= mirror_iostatus_reset, 699 .complete = mirror_complete, 700 }; 701 702 static const BlockJobDriver commit_active_job_driver = { 703 .instance_size = sizeof(MirrorBlockJob), 704 .job_type = BLOCK_JOB_TYPE_COMMIT, 705 .set_speed = mirror_set_speed, 706 .iostatus_reset 707 = mirror_iostatus_reset, 708 .complete = mirror_complete, 709 }; 710 711 static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target, 712 const char *replaces, 713 int64_t speed, uint32_t granularity, 714 int64_t buf_size, 715 BlockdevOnError on_source_error, 716 BlockdevOnError on_target_error, 717 bool unmap, 718 BlockCompletionFunc *cb, 719 void *opaque, Error **errp, 720 const BlockJobDriver *driver, 721 bool is_none_mode, BlockDriverState *base) 722 { 723 MirrorBlockJob *s; 724 BlockDriverState *replaced_bs; 725 726 if (granularity == 0) { 727 granularity = bdrv_get_default_bitmap_granularity(target); 728 } 729 730 assert ((granularity & (granularity - 1)) == 0); 731 732 if ((on_source_error == BLOCKDEV_ON_ERROR_STOP || 733 on_source_error == BLOCKDEV_ON_ERROR_ENOSPC) && 734 (!bs->blk || !blk_iostatus_is_enabled(bs->blk))) { 735 error_setg(errp, QERR_INVALID_PARAMETER, "on-source-error"); 736 return; 737 } 738 739 if (buf_size < 0) { 740 error_setg(errp, "Invalid parameter 'buf-size'"); 741 return; 742 } 743 744 if (buf_size == 0) { 745 buf_size = DEFAULT_MIRROR_BUF_SIZE; 746 } 747 748 /* We can't support this case as long as the block layer can't handle 749 * multiple BlockBackends per BlockDriverState. */ 750 if (replaces) { 751 replaced_bs = bdrv_lookup_bs(replaces, replaces, errp); 752 if (replaced_bs == NULL) { 753 return; 754 } 755 } else { 756 replaced_bs = bs; 757 } 758 if (replaced_bs->blk && target->blk) { 759 error_setg(errp, "Can't create node with two BlockBackends"); 760 return; 761 } 762 763 s = block_job_create(driver, bs, speed, cb, opaque, errp); 764 if (!s) { 765 return; 766 } 767 768 s->replaces = g_strdup(replaces); 769 s->on_source_error = on_source_error; 770 s->on_target_error = on_target_error; 771 s->target = target; 772 s->is_none_mode = is_none_mode; 773 s->base = base; 774 s->granularity = granularity; 775 s->buf_size = ROUND_UP(buf_size, granularity); 776 s->unmap = unmap; 777 778 s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp); 779 if (!s->dirty_bitmap) { 780 g_free(s->replaces); 781 block_job_unref(&s->common); 782 return; 783 } 784 785 bdrv_op_block_all(s->target, s->common.blocker); 786 787 bdrv_set_enable_write_cache(s->target, true); 788 if (s->target->blk) { 789 blk_set_on_error(s->target->blk, on_target_error, on_target_error); 790 blk_iostatus_enable(s->target->blk); 791 } 792 s->common.co = qemu_coroutine_create(mirror_run); 793 trace_mirror_start(bs, s, s->common.co, opaque); 794 qemu_coroutine_enter(s->common.co, s); 795 } 796 797 void mirror_start(BlockDriverState *bs, BlockDriverState *target, 798 const char *replaces, 799 int64_t speed, uint32_t granularity, int64_t buf_size, 800 MirrorSyncMode mode, BlockdevOnError on_source_error, 801 BlockdevOnError on_target_error, 802 bool unmap, 803 BlockCompletionFunc *cb, 804 void *opaque, Error **errp) 805 { 806 bool is_none_mode; 807 BlockDriverState *base; 808 809 if (mode == MIRROR_SYNC_MODE_INCREMENTAL) { 810 error_setg(errp, "Sync mode 'incremental' not supported"); 811 return; 812 } 813 is_none_mode = mode == MIRROR_SYNC_MODE_NONE; 814 base = mode == MIRROR_SYNC_MODE_TOP ? backing_bs(bs) : NULL; 815 mirror_start_job(bs, target, replaces, 816 speed, granularity, buf_size, 817 on_source_error, on_target_error, unmap, cb, opaque, errp, 818 &mirror_job_driver, is_none_mode, base); 819 } 820 821 void commit_active_start(BlockDriverState *bs, BlockDriverState *base, 822 int64_t speed, 823 BlockdevOnError on_error, 824 BlockCompletionFunc *cb, 825 void *opaque, Error **errp) 826 { 827 int64_t length, base_length; 828 int orig_base_flags; 829 int ret; 830 Error *local_err = NULL; 831 832 orig_base_flags = bdrv_get_flags(base); 833 834 if (bdrv_reopen(base, bs->open_flags, errp)) { 835 return; 836 } 837 838 length = bdrv_getlength(bs); 839 if (length < 0) { 840 error_setg_errno(errp, -length, 841 "Unable to determine length of %s", bs->filename); 842 goto error_restore_flags; 843 } 844 845 base_length = bdrv_getlength(base); 846 if (base_length < 0) { 847 error_setg_errno(errp, -base_length, 848 "Unable to determine length of %s", base->filename); 849 goto error_restore_flags; 850 } 851 852 if (length > base_length) { 853 ret = bdrv_truncate(base, length); 854 if (ret < 0) { 855 error_setg_errno(errp, -ret, 856 "Top image %s is larger than base image %s, and " 857 "resize of base image failed", 858 bs->filename, base->filename); 859 goto error_restore_flags; 860 } 861 } 862 863 bdrv_ref(base); 864 mirror_start_job(bs, base, NULL, speed, 0, 0, 865 on_error, on_error, false, cb, opaque, &local_err, 866 &commit_active_job_driver, false, base); 867 if (local_err) { 868 error_propagate(errp, local_err); 869 goto error_restore_flags; 870 } 871 872 return; 873 874 error_restore_flags: 875 /* ignore error and errp for bdrv_reopen, because we want to propagate 876 * the original error */ 877 bdrv_reopen(base, orig_base_flags, NULL); 878 return; 879 } 880