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 "qemu/cutils.h" 16 #include "trace.h" 17 #include "block/blockjob_int.h" 18 #include "block/block_int.h" 19 #include "sysemu/block-backend.h" 20 #include "qapi/error.h" 21 #include "qapi/qmp/qerror.h" 22 #include "qemu/ratelimit.h" 23 #include "qemu/bitmap.h" 24 25 #define SLICE_TIME 100000000ULL /* ns */ 26 #define MAX_IN_FLIGHT 16 27 #define MAX_IO_SECTORS ((1 << 20) >> BDRV_SECTOR_BITS) /* 1 Mb */ 28 #define DEFAULT_MIRROR_BUF_SIZE \ 29 (MAX_IN_FLIGHT * MAX_IO_SECTORS * BDRV_SECTOR_SIZE) 30 31 /* The mirroring buffer is a list of granularity-sized chunks. 32 * Free chunks are organized in a list. 33 */ 34 typedef struct MirrorBuffer { 35 QSIMPLEQ_ENTRY(MirrorBuffer) next; 36 } MirrorBuffer; 37 38 typedef struct MirrorBlockJob { 39 BlockJob common; 40 RateLimit limit; 41 BlockBackend *target; 42 BlockDriverState *mirror_top_bs; 43 BlockDriverState *source; 44 BlockDriverState *base; 45 46 /* The name of the graph node to replace */ 47 char *replaces; 48 /* The BDS to replace */ 49 BlockDriverState *to_replace; 50 /* Used to block operations on the drive-mirror-replace target */ 51 Error *replace_blocker; 52 bool is_none_mode; 53 BlockMirrorBackingMode backing_mode; 54 BlockdevOnError on_source_error, on_target_error; 55 bool synced; 56 bool should_complete; 57 int64_t granularity; 58 size_t buf_size; 59 int64_t bdev_length; 60 unsigned long *cow_bitmap; 61 BdrvDirtyBitmap *dirty_bitmap; 62 BdrvDirtyBitmapIter *dbi; 63 uint8_t *buf; 64 QSIMPLEQ_HEAD(, MirrorBuffer) buf_free; 65 int buf_free_count; 66 67 uint64_t last_pause_ns; 68 unsigned long *in_flight_bitmap; 69 int in_flight; 70 int64_t sectors_in_flight; 71 int ret; 72 bool unmap; 73 bool waiting_for_io; 74 int target_cluster_sectors; 75 int max_iov; 76 bool initial_zeroing_ongoing; 77 } MirrorBlockJob; 78 79 typedef struct MirrorOp { 80 MirrorBlockJob *s; 81 QEMUIOVector qiov; 82 int64_t sector_num; 83 int nb_sectors; 84 } MirrorOp; 85 86 static BlockErrorAction mirror_error_action(MirrorBlockJob *s, bool read, 87 int error) 88 { 89 s->synced = false; 90 if (read) { 91 return block_job_error_action(&s->common, s->on_source_error, 92 true, error); 93 } else { 94 return block_job_error_action(&s->common, s->on_target_error, 95 false, error); 96 } 97 } 98 99 static void mirror_iteration_done(MirrorOp *op, int ret) 100 { 101 MirrorBlockJob *s = op->s; 102 struct iovec *iov; 103 int64_t chunk_num; 104 int i, nb_chunks, sectors_per_chunk; 105 106 trace_mirror_iteration_done(s, op->sector_num, op->nb_sectors, ret); 107 108 s->in_flight--; 109 s->sectors_in_flight -= op->nb_sectors; 110 iov = op->qiov.iov; 111 for (i = 0; i < op->qiov.niov; i++) { 112 MirrorBuffer *buf = (MirrorBuffer *) iov[i].iov_base; 113 QSIMPLEQ_INSERT_TAIL(&s->buf_free, buf, next); 114 s->buf_free_count++; 115 } 116 117 sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; 118 chunk_num = op->sector_num / sectors_per_chunk; 119 nb_chunks = DIV_ROUND_UP(op->nb_sectors, sectors_per_chunk); 120 bitmap_clear(s->in_flight_bitmap, chunk_num, nb_chunks); 121 if (ret >= 0) { 122 if (s->cow_bitmap) { 123 bitmap_set(s->cow_bitmap, chunk_num, nb_chunks); 124 } 125 if (!s->initial_zeroing_ongoing) { 126 s->common.offset += (uint64_t)op->nb_sectors * BDRV_SECTOR_SIZE; 127 } 128 } 129 qemu_iovec_destroy(&op->qiov); 130 g_free(op); 131 132 if (s->waiting_for_io) { 133 qemu_coroutine_enter(s->common.co); 134 } 135 } 136 137 static void mirror_write_complete(void *opaque, int ret) 138 { 139 MirrorOp *op = opaque; 140 MirrorBlockJob *s = op->s; 141 142 aio_context_acquire(blk_get_aio_context(s->common.blk)); 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, false, -ret); 148 if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) { 149 s->ret = ret; 150 } 151 } 152 mirror_iteration_done(op, ret); 153 aio_context_release(blk_get_aio_context(s->common.blk)); 154 } 155 156 static void mirror_read_complete(void *opaque, int ret) 157 { 158 MirrorOp *op = opaque; 159 MirrorBlockJob *s = op->s; 160 161 aio_context_acquire(blk_get_aio_context(s->common.blk)); 162 if (ret < 0) { 163 BlockErrorAction action; 164 165 bdrv_set_dirty_bitmap(s->dirty_bitmap, op->sector_num, op->nb_sectors); 166 action = mirror_error_action(s, true, -ret); 167 if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) { 168 s->ret = ret; 169 } 170 171 mirror_iteration_done(op, ret); 172 } else { 173 blk_aio_pwritev(s->target, op->sector_num * BDRV_SECTOR_SIZE, &op->qiov, 174 0, mirror_write_complete, op); 175 } 176 aio_context_release(blk_get_aio_context(s->common.blk)); 177 } 178 179 static inline void mirror_clip_sectors(MirrorBlockJob *s, 180 int64_t sector_num, 181 int *nb_sectors) 182 { 183 *nb_sectors = MIN(*nb_sectors, 184 s->bdev_length / BDRV_SECTOR_SIZE - sector_num); 185 } 186 187 /* Round sector_num and/or nb_sectors to target cluster if COW is needed, and 188 * return the offset of the adjusted tail sector against original. */ 189 static int mirror_cow_align(MirrorBlockJob *s, 190 int64_t *sector_num, 191 int *nb_sectors) 192 { 193 bool need_cow; 194 int ret = 0; 195 int chunk_sectors = s->granularity >> BDRV_SECTOR_BITS; 196 int64_t align_sector_num = *sector_num; 197 int align_nb_sectors = *nb_sectors; 198 int max_sectors = chunk_sectors * s->max_iov; 199 200 need_cow = !test_bit(*sector_num / chunk_sectors, s->cow_bitmap); 201 need_cow |= !test_bit((*sector_num + *nb_sectors - 1) / chunk_sectors, 202 s->cow_bitmap); 203 if (need_cow) { 204 bdrv_round_sectors_to_clusters(blk_bs(s->target), *sector_num, 205 *nb_sectors, &align_sector_num, 206 &align_nb_sectors); 207 } 208 209 if (align_nb_sectors > max_sectors) { 210 align_nb_sectors = max_sectors; 211 if (need_cow) { 212 align_nb_sectors = QEMU_ALIGN_DOWN(align_nb_sectors, 213 s->target_cluster_sectors); 214 } 215 } 216 /* Clipping may result in align_nb_sectors unaligned to chunk boundary, but 217 * that doesn't matter because it's already the end of source image. */ 218 mirror_clip_sectors(s, align_sector_num, &align_nb_sectors); 219 220 ret = align_sector_num + align_nb_sectors - (*sector_num + *nb_sectors); 221 *sector_num = align_sector_num; 222 *nb_sectors = align_nb_sectors; 223 assert(ret >= 0); 224 return ret; 225 } 226 227 static inline void mirror_wait_for_io(MirrorBlockJob *s) 228 { 229 assert(!s->waiting_for_io); 230 s->waiting_for_io = true; 231 qemu_coroutine_yield(); 232 s->waiting_for_io = false; 233 } 234 235 /* Submit async read while handling COW. 236 * Returns: The number of sectors copied after and including sector_num, 237 * excluding any sectors copied prior to sector_num due to alignment. 238 * This will be nb_sectors if no alignment is necessary, or 239 * (new_end - sector_num) if tail is rounded up or down due to 240 * alignment or buffer limit. 241 */ 242 static int mirror_do_read(MirrorBlockJob *s, int64_t sector_num, 243 int nb_sectors) 244 { 245 BlockBackend *source = s->common.blk; 246 int sectors_per_chunk, nb_chunks; 247 int ret; 248 MirrorOp *op; 249 int max_sectors; 250 251 sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; 252 max_sectors = sectors_per_chunk * s->max_iov; 253 254 /* We can only handle as much as buf_size at a time. */ 255 nb_sectors = MIN(s->buf_size >> BDRV_SECTOR_BITS, nb_sectors); 256 nb_sectors = MIN(max_sectors, nb_sectors); 257 assert(nb_sectors); 258 ret = nb_sectors; 259 260 if (s->cow_bitmap) { 261 ret += mirror_cow_align(s, §or_num, &nb_sectors); 262 } 263 assert(nb_sectors << BDRV_SECTOR_BITS <= s->buf_size); 264 /* The sector range must meet granularity because: 265 * 1) Caller passes in aligned values; 266 * 2) mirror_cow_align is used only when target cluster is larger. */ 267 assert(!(sector_num % sectors_per_chunk)); 268 nb_chunks = DIV_ROUND_UP(nb_sectors, sectors_per_chunk); 269 270 while (s->buf_free_count < nb_chunks) { 271 trace_mirror_yield_in_flight(s, sector_num, s->in_flight); 272 mirror_wait_for_io(s); 273 } 274 275 /* Allocate a MirrorOp that is used as an AIO callback. */ 276 op = g_new(MirrorOp, 1); 277 op->s = s; 278 op->sector_num = sector_num; 279 op->nb_sectors = nb_sectors; 280 281 /* Now make a QEMUIOVector taking enough granularity-sized chunks 282 * from s->buf_free. 283 */ 284 qemu_iovec_init(&op->qiov, nb_chunks); 285 while (nb_chunks-- > 0) { 286 MirrorBuffer *buf = QSIMPLEQ_FIRST(&s->buf_free); 287 size_t remaining = nb_sectors * BDRV_SECTOR_SIZE - op->qiov.size; 288 289 QSIMPLEQ_REMOVE_HEAD(&s->buf_free, next); 290 s->buf_free_count--; 291 qemu_iovec_add(&op->qiov, buf, MIN(s->granularity, remaining)); 292 } 293 294 /* Copy the dirty cluster. */ 295 s->in_flight++; 296 s->sectors_in_flight += nb_sectors; 297 trace_mirror_one_iteration(s, sector_num, nb_sectors); 298 299 blk_aio_preadv(source, sector_num * BDRV_SECTOR_SIZE, &op->qiov, 0, 300 mirror_read_complete, op); 301 return ret; 302 } 303 304 static void mirror_do_zero_or_discard(MirrorBlockJob *s, 305 int64_t sector_num, 306 int nb_sectors, 307 bool is_discard) 308 { 309 MirrorOp *op; 310 311 /* Allocate a MirrorOp that is used as an AIO callback. The qiov is zeroed 312 * so the freeing in mirror_iteration_done is nop. */ 313 op = g_new0(MirrorOp, 1); 314 op->s = s; 315 op->sector_num = sector_num; 316 op->nb_sectors = nb_sectors; 317 318 s->in_flight++; 319 s->sectors_in_flight += nb_sectors; 320 if (is_discard) { 321 blk_aio_pdiscard(s->target, sector_num << BDRV_SECTOR_BITS, 322 op->nb_sectors << BDRV_SECTOR_BITS, 323 mirror_write_complete, op); 324 } else { 325 blk_aio_pwrite_zeroes(s->target, sector_num * BDRV_SECTOR_SIZE, 326 op->nb_sectors * BDRV_SECTOR_SIZE, 327 s->unmap ? BDRV_REQ_MAY_UNMAP : 0, 328 mirror_write_complete, op); 329 } 330 } 331 332 static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) 333 { 334 BlockDriverState *source = s->source; 335 int64_t sector_num, first_chunk; 336 uint64_t delay_ns = 0; 337 /* At least the first dirty chunk is mirrored in one iteration. */ 338 int nb_chunks = 1; 339 int64_t end = s->bdev_length / BDRV_SECTOR_SIZE; 340 int sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; 341 bool write_zeroes_ok = bdrv_can_write_zeroes_with_unmap(blk_bs(s->target)); 342 int max_io_sectors = MAX((s->buf_size >> BDRV_SECTOR_BITS) / MAX_IN_FLIGHT, 343 MAX_IO_SECTORS); 344 345 bdrv_dirty_bitmap_lock(s->dirty_bitmap); 346 sector_num = bdrv_dirty_iter_next(s->dbi); 347 if (sector_num < 0) { 348 bdrv_set_dirty_iter(s->dbi, 0); 349 sector_num = bdrv_dirty_iter_next(s->dbi); 350 trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap)); 351 assert(sector_num >= 0); 352 } 353 bdrv_dirty_bitmap_unlock(s->dirty_bitmap); 354 355 first_chunk = sector_num / sectors_per_chunk; 356 while (test_bit(first_chunk, s->in_flight_bitmap)) { 357 trace_mirror_yield_in_flight(s, sector_num, s->in_flight); 358 mirror_wait_for_io(s); 359 } 360 361 block_job_pause_point(&s->common); 362 363 /* Find the number of consective dirty chunks following the first dirty 364 * one, and wait for in flight requests in them. */ 365 bdrv_dirty_bitmap_lock(s->dirty_bitmap); 366 while (nb_chunks * sectors_per_chunk < (s->buf_size >> BDRV_SECTOR_BITS)) { 367 int64_t next_dirty; 368 int64_t next_sector = sector_num + nb_chunks * sectors_per_chunk; 369 int64_t next_chunk = next_sector / sectors_per_chunk; 370 if (next_sector >= end || 371 !bdrv_get_dirty_locked(source, s->dirty_bitmap, next_sector)) { 372 break; 373 } 374 if (test_bit(next_chunk, s->in_flight_bitmap)) { 375 break; 376 } 377 378 next_dirty = bdrv_dirty_iter_next(s->dbi); 379 if (next_dirty > next_sector || next_dirty < 0) { 380 /* The bitmap iterator's cache is stale, refresh it */ 381 bdrv_set_dirty_iter(s->dbi, next_sector); 382 next_dirty = bdrv_dirty_iter_next(s->dbi); 383 } 384 assert(next_dirty == next_sector); 385 nb_chunks++; 386 } 387 388 /* Clear dirty bits before querying the block status, because 389 * calling bdrv_get_block_status_above could yield - if some blocks are 390 * marked dirty in this window, we need to know. 391 */ 392 bdrv_reset_dirty_bitmap_locked(s->dirty_bitmap, sector_num, 393 nb_chunks * sectors_per_chunk); 394 bdrv_dirty_bitmap_unlock(s->dirty_bitmap); 395 396 bitmap_set(s->in_flight_bitmap, sector_num / sectors_per_chunk, nb_chunks); 397 while (nb_chunks > 0 && sector_num < end) { 398 int64_t ret; 399 int io_sectors, io_sectors_acct; 400 BlockDriverState *file; 401 enum MirrorMethod { 402 MIRROR_METHOD_COPY, 403 MIRROR_METHOD_ZERO, 404 MIRROR_METHOD_DISCARD 405 } mirror_method = MIRROR_METHOD_COPY; 406 407 assert(!(sector_num % sectors_per_chunk)); 408 ret = bdrv_get_block_status_above(source, NULL, sector_num, 409 nb_chunks * sectors_per_chunk, 410 &io_sectors, &file); 411 if (ret < 0) { 412 io_sectors = MIN(nb_chunks * sectors_per_chunk, max_io_sectors); 413 } else if (ret & BDRV_BLOCK_DATA) { 414 io_sectors = MIN(io_sectors, max_io_sectors); 415 } 416 417 io_sectors -= io_sectors % sectors_per_chunk; 418 if (io_sectors < sectors_per_chunk) { 419 io_sectors = sectors_per_chunk; 420 } else if (ret >= 0 && !(ret & BDRV_BLOCK_DATA)) { 421 int64_t target_sector_num; 422 int target_nb_sectors; 423 bdrv_round_sectors_to_clusters(blk_bs(s->target), sector_num, 424 io_sectors, &target_sector_num, 425 &target_nb_sectors); 426 if (target_sector_num == sector_num && 427 target_nb_sectors == io_sectors) { 428 mirror_method = ret & BDRV_BLOCK_ZERO ? 429 MIRROR_METHOD_ZERO : 430 MIRROR_METHOD_DISCARD; 431 } 432 } 433 434 while (s->in_flight >= MAX_IN_FLIGHT) { 435 trace_mirror_yield_in_flight(s, sector_num, s->in_flight); 436 mirror_wait_for_io(s); 437 } 438 439 if (s->ret < 0) { 440 return 0; 441 } 442 443 mirror_clip_sectors(s, sector_num, &io_sectors); 444 switch (mirror_method) { 445 case MIRROR_METHOD_COPY: 446 io_sectors = mirror_do_read(s, sector_num, io_sectors); 447 io_sectors_acct = io_sectors; 448 break; 449 case MIRROR_METHOD_ZERO: 450 case MIRROR_METHOD_DISCARD: 451 mirror_do_zero_or_discard(s, sector_num, io_sectors, 452 mirror_method == MIRROR_METHOD_DISCARD); 453 if (write_zeroes_ok) { 454 io_sectors_acct = 0; 455 } else { 456 io_sectors_acct = io_sectors; 457 } 458 break; 459 default: 460 abort(); 461 } 462 assert(io_sectors); 463 sector_num += io_sectors; 464 nb_chunks -= DIV_ROUND_UP(io_sectors, sectors_per_chunk); 465 if (s->common.speed) { 466 delay_ns = ratelimit_calculate_delay(&s->limit, io_sectors_acct); 467 } 468 } 469 return delay_ns; 470 } 471 472 static void mirror_free_init(MirrorBlockJob *s) 473 { 474 int granularity = s->granularity; 475 size_t buf_size = s->buf_size; 476 uint8_t *buf = s->buf; 477 478 assert(s->buf_free_count == 0); 479 QSIMPLEQ_INIT(&s->buf_free); 480 while (buf_size != 0) { 481 MirrorBuffer *cur = (MirrorBuffer *)buf; 482 QSIMPLEQ_INSERT_TAIL(&s->buf_free, cur, next); 483 s->buf_free_count++; 484 buf_size -= granularity; 485 buf += granularity; 486 } 487 } 488 489 /* This is also used for the .pause callback. There is no matching 490 * mirror_resume() because mirror_run() will begin iterating again 491 * when the job is resumed. 492 */ 493 static void mirror_wait_for_all_io(MirrorBlockJob *s) 494 { 495 while (s->in_flight > 0) { 496 mirror_wait_for_io(s); 497 } 498 } 499 500 typedef struct { 501 int ret; 502 } MirrorExitData; 503 504 static void mirror_exit(BlockJob *job, void *opaque) 505 { 506 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 507 MirrorExitData *data = opaque; 508 AioContext *replace_aio_context = NULL; 509 BlockDriverState *src = s->source; 510 BlockDriverState *target_bs = blk_bs(s->target); 511 BlockDriverState *mirror_top_bs = s->mirror_top_bs; 512 Error *local_err = NULL; 513 514 bdrv_release_dirty_bitmap(src, s->dirty_bitmap); 515 516 /* Make sure that the source BDS doesn't go away before we called 517 * block_job_completed(). */ 518 bdrv_ref(src); 519 bdrv_ref(mirror_top_bs); 520 bdrv_ref(target_bs); 521 522 /* Remove target parent that still uses BLK_PERM_WRITE/RESIZE before 523 * inserting target_bs at s->to_replace, where we might not be able to get 524 * these permissions. 525 * 526 * Note that blk_unref() alone doesn't necessarily drop permissions because 527 * we might be running nested inside mirror_drain(), which takes an extra 528 * reference, so use an explicit blk_set_perm() first. */ 529 blk_set_perm(s->target, 0, BLK_PERM_ALL, &error_abort); 530 blk_unref(s->target); 531 s->target = NULL; 532 533 /* We don't access the source any more. Dropping any WRITE/RESIZE is 534 * required before it could become a backing file of target_bs. */ 535 bdrv_child_try_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL, 536 &error_abort); 537 if (s->backing_mode == MIRROR_SOURCE_BACKING_CHAIN) { 538 BlockDriverState *backing = s->is_none_mode ? src : s->base; 539 if (backing_bs(target_bs) != backing) { 540 bdrv_set_backing_hd(target_bs, backing, &local_err); 541 if (local_err) { 542 error_report_err(local_err); 543 data->ret = -EPERM; 544 } 545 } 546 } 547 548 if (s->to_replace) { 549 replace_aio_context = bdrv_get_aio_context(s->to_replace); 550 aio_context_acquire(replace_aio_context); 551 } 552 553 if (s->should_complete && data->ret == 0) { 554 BlockDriverState *to_replace = src; 555 if (s->to_replace) { 556 to_replace = s->to_replace; 557 } 558 559 if (bdrv_get_flags(target_bs) != bdrv_get_flags(to_replace)) { 560 bdrv_reopen(target_bs, bdrv_get_flags(to_replace), NULL); 561 } 562 563 /* The mirror job has no requests in flight any more, but we need to 564 * drain potential other users of the BDS before changing the graph. */ 565 bdrv_drained_begin(target_bs); 566 bdrv_replace_node(to_replace, target_bs, &local_err); 567 bdrv_drained_end(target_bs); 568 if (local_err) { 569 error_report_err(local_err); 570 data->ret = -EPERM; 571 } 572 } 573 if (s->to_replace) { 574 bdrv_op_unblock_all(s->to_replace, s->replace_blocker); 575 error_free(s->replace_blocker); 576 bdrv_unref(s->to_replace); 577 } 578 if (replace_aio_context) { 579 aio_context_release(replace_aio_context); 580 } 581 g_free(s->replaces); 582 bdrv_unref(target_bs); 583 584 /* Remove the mirror filter driver from the graph. Before this, get rid of 585 * the blockers on the intermediate nodes so that the resulting state is 586 * valid. Also give up permissions on mirror_top_bs->backing, which might 587 * block the removal. */ 588 block_job_remove_all_bdrv(job); 589 bdrv_child_try_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL, 590 &error_abort); 591 bdrv_replace_node(mirror_top_bs, backing_bs(mirror_top_bs), &error_abort); 592 593 /* We just changed the BDS the job BB refers to (with either or both of the 594 * bdrv_replace_node() calls), so switch the BB back so the cleanup does 595 * the right thing. We don't need any permissions any more now. */ 596 blk_remove_bs(job->blk); 597 blk_set_perm(job->blk, 0, BLK_PERM_ALL, &error_abort); 598 blk_insert_bs(job->blk, mirror_top_bs, &error_abort); 599 600 block_job_completed(&s->common, data->ret); 601 602 g_free(data); 603 bdrv_drained_end(src); 604 bdrv_unref(mirror_top_bs); 605 bdrv_unref(src); 606 } 607 608 static void mirror_throttle(MirrorBlockJob *s) 609 { 610 int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 611 612 if (now - s->last_pause_ns > SLICE_TIME) { 613 s->last_pause_ns = now; 614 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, 0); 615 } else { 616 block_job_pause_point(&s->common); 617 } 618 } 619 620 static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s) 621 { 622 int64_t sector_num, end; 623 BlockDriverState *base = s->base; 624 BlockDriverState *bs = s->source; 625 BlockDriverState *target_bs = blk_bs(s->target); 626 int ret, n; 627 628 end = s->bdev_length / BDRV_SECTOR_SIZE; 629 630 if (base == NULL && !bdrv_has_zero_init(target_bs)) { 631 if (!bdrv_can_write_zeroes_with_unmap(target_bs)) { 632 bdrv_set_dirty_bitmap(s->dirty_bitmap, 0, end); 633 return 0; 634 } 635 636 s->initial_zeroing_ongoing = true; 637 for (sector_num = 0; sector_num < end; ) { 638 int nb_sectors = MIN(end - sector_num, 639 QEMU_ALIGN_DOWN(INT_MAX, s->granularity) >> BDRV_SECTOR_BITS); 640 641 mirror_throttle(s); 642 643 if (block_job_is_cancelled(&s->common)) { 644 s->initial_zeroing_ongoing = false; 645 return 0; 646 } 647 648 if (s->in_flight >= MAX_IN_FLIGHT) { 649 trace_mirror_yield(s, UINT64_MAX, s->buf_free_count, 650 s->in_flight); 651 mirror_wait_for_io(s); 652 continue; 653 } 654 655 mirror_do_zero_or_discard(s, sector_num, nb_sectors, false); 656 sector_num += nb_sectors; 657 } 658 659 mirror_wait_for_all_io(s); 660 s->initial_zeroing_ongoing = false; 661 } 662 663 /* First part, loop on the sectors and initialize the dirty bitmap. */ 664 for (sector_num = 0; sector_num < end; ) { 665 /* Just to make sure we are not exceeding int limit. */ 666 int nb_sectors = MIN(INT_MAX >> BDRV_SECTOR_BITS, 667 end - sector_num); 668 669 mirror_throttle(s); 670 671 if (block_job_is_cancelled(&s->common)) { 672 return 0; 673 } 674 675 ret = bdrv_is_allocated_above(bs, base, sector_num, nb_sectors, &n); 676 if (ret < 0) { 677 return ret; 678 } 679 680 assert(n > 0); 681 if (ret == 1) { 682 bdrv_set_dirty_bitmap(s->dirty_bitmap, sector_num, n); 683 } 684 sector_num += n; 685 } 686 return 0; 687 } 688 689 /* Called when going out of the streaming phase to flush the bulk of the 690 * data to the medium, or just before completing. 691 */ 692 static int mirror_flush(MirrorBlockJob *s) 693 { 694 int ret = blk_flush(s->target); 695 if (ret < 0) { 696 if (mirror_error_action(s, false, -ret) == BLOCK_ERROR_ACTION_REPORT) { 697 s->ret = ret; 698 } 699 } 700 return ret; 701 } 702 703 static void coroutine_fn mirror_run(void *opaque) 704 { 705 MirrorBlockJob *s = opaque; 706 MirrorExitData *data; 707 BlockDriverState *bs = s->source; 708 BlockDriverState *target_bs = blk_bs(s->target); 709 bool need_drain = true; 710 int64_t length; 711 BlockDriverInfo bdi; 712 char backing_filename[2]; /* we only need 2 characters because we are only 713 checking for a NULL string */ 714 int ret = 0; 715 int target_cluster_size = BDRV_SECTOR_SIZE; 716 717 if (block_job_is_cancelled(&s->common)) { 718 goto immediate_exit; 719 } 720 721 s->bdev_length = bdrv_getlength(bs); 722 if (s->bdev_length < 0) { 723 ret = s->bdev_length; 724 goto immediate_exit; 725 } 726 727 /* Active commit must resize the base image if its size differs from the 728 * active layer. */ 729 if (s->base == blk_bs(s->target)) { 730 int64_t base_length; 731 732 base_length = blk_getlength(s->target); 733 if (base_length < 0) { 734 ret = base_length; 735 goto immediate_exit; 736 } 737 738 if (s->bdev_length > base_length) { 739 ret = blk_truncate(s->target, s->bdev_length, NULL); 740 if (ret < 0) { 741 goto immediate_exit; 742 } 743 } 744 } 745 746 if (s->bdev_length == 0) { 747 /* Report BLOCK_JOB_READY and wait for complete. */ 748 block_job_event_ready(&s->common); 749 s->synced = true; 750 while (!block_job_is_cancelled(&s->common) && !s->should_complete) { 751 block_job_yield(&s->common); 752 } 753 s->common.cancelled = false; 754 goto immediate_exit; 755 } 756 757 length = DIV_ROUND_UP(s->bdev_length, s->granularity); 758 s->in_flight_bitmap = bitmap_new(length); 759 760 /* If we have no backing file yet in the destination, we cannot let 761 * the destination do COW. Instead, we copy sectors around the 762 * dirty data if needed. We need a bitmap to do that. 763 */ 764 bdrv_get_backing_filename(target_bs, backing_filename, 765 sizeof(backing_filename)); 766 if (!bdrv_get_info(target_bs, &bdi) && bdi.cluster_size) { 767 target_cluster_size = bdi.cluster_size; 768 } 769 if (backing_filename[0] && !target_bs->backing 770 && s->granularity < target_cluster_size) { 771 s->buf_size = MAX(s->buf_size, target_cluster_size); 772 s->cow_bitmap = bitmap_new(length); 773 } 774 s->target_cluster_sectors = target_cluster_size >> BDRV_SECTOR_BITS; 775 s->max_iov = MIN(bs->bl.max_iov, target_bs->bl.max_iov); 776 777 s->buf = qemu_try_blockalign(bs, s->buf_size); 778 if (s->buf == NULL) { 779 ret = -ENOMEM; 780 goto immediate_exit; 781 } 782 783 mirror_free_init(s); 784 785 s->last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 786 if (!s->is_none_mode) { 787 ret = mirror_dirty_init(s); 788 if (ret < 0 || block_job_is_cancelled(&s->common)) { 789 goto immediate_exit; 790 } 791 } 792 793 assert(!s->dbi); 794 s->dbi = bdrv_dirty_iter_new(s->dirty_bitmap, 0); 795 for (;;) { 796 uint64_t delay_ns = 0; 797 int64_t cnt, delta; 798 bool should_complete; 799 800 if (s->ret < 0) { 801 ret = s->ret; 802 goto immediate_exit; 803 } 804 805 block_job_pause_point(&s->common); 806 807 cnt = bdrv_get_dirty_count(s->dirty_bitmap); 808 /* s->common.offset contains the number of bytes already processed so 809 * far, cnt is the number of dirty sectors remaining and 810 * s->sectors_in_flight is the number of sectors currently being 811 * processed; together those are the current total operation length */ 812 s->common.len = s->common.offset + 813 (cnt + s->sectors_in_flight) * BDRV_SECTOR_SIZE; 814 815 /* Note that even when no rate limit is applied we need to yield 816 * periodically with no pending I/O so that bdrv_drain_all() returns. 817 * We do so every SLICE_TIME nanoseconds, or when there is an error, 818 * or when the source is clean, whichever comes first. 819 */ 820 delta = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - s->last_pause_ns; 821 if (delta < SLICE_TIME && 822 s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) { 823 if (s->in_flight >= MAX_IN_FLIGHT || s->buf_free_count == 0 || 824 (cnt == 0 && s->in_flight > 0)) { 825 trace_mirror_yield(s, cnt, s->buf_free_count, s->in_flight); 826 mirror_wait_for_io(s); 827 continue; 828 } else if (cnt != 0) { 829 delay_ns = mirror_iteration(s); 830 } 831 } 832 833 should_complete = false; 834 if (s->in_flight == 0 && cnt == 0) { 835 trace_mirror_before_flush(s); 836 if (!s->synced) { 837 if (mirror_flush(s) < 0) { 838 /* Go check s->ret. */ 839 continue; 840 } 841 /* We're out of the streaming phase. From now on, if the job 842 * is cancelled we will actually complete all pending I/O and 843 * report completion. This way, block-job-cancel will leave 844 * the target in a consistent state. 845 */ 846 block_job_event_ready(&s->common); 847 s->synced = true; 848 } 849 850 should_complete = s->should_complete || 851 block_job_is_cancelled(&s->common); 852 cnt = bdrv_get_dirty_count(s->dirty_bitmap); 853 } 854 855 if (cnt == 0 && should_complete) { 856 /* The dirty bitmap is not updated while operations are pending. 857 * If we're about to exit, wait for pending operations before 858 * calling bdrv_get_dirty_count(bs), or we may exit while the 859 * source has dirty data to copy! 860 * 861 * Note that I/O can be submitted by the guest while 862 * mirror_populate runs, so pause it now. Before deciding 863 * whether to switch to target check one last time if I/O has 864 * come in the meanwhile, and if not flush the data to disk. 865 */ 866 trace_mirror_before_drain(s, cnt); 867 868 bdrv_drained_begin(bs); 869 cnt = bdrv_get_dirty_count(s->dirty_bitmap); 870 if (cnt > 0 || mirror_flush(s) < 0) { 871 bdrv_drained_end(bs); 872 continue; 873 } 874 875 /* The two disks are in sync. Exit and report successful 876 * completion. 877 */ 878 assert(QLIST_EMPTY(&bs->tracked_requests)); 879 s->common.cancelled = false; 880 need_drain = false; 881 break; 882 } 883 884 ret = 0; 885 trace_mirror_before_sleep(s, cnt, s->synced, delay_ns); 886 if (!s->synced) { 887 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); 888 if (block_job_is_cancelled(&s->common)) { 889 break; 890 } 891 } else if (!should_complete) { 892 delay_ns = (s->in_flight == 0 && cnt == 0 ? SLICE_TIME : 0); 893 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); 894 } 895 s->last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 896 } 897 898 immediate_exit: 899 if (s->in_flight > 0) { 900 /* We get here only if something went wrong. Either the job failed, 901 * or it was cancelled prematurely so that we do not guarantee that 902 * the target is a copy of the source. 903 */ 904 assert(ret < 0 || (!s->synced && block_job_is_cancelled(&s->common))); 905 assert(need_drain); 906 mirror_wait_for_all_io(s); 907 } 908 909 assert(s->in_flight == 0); 910 qemu_vfree(s->buf); 911 g_free(s->cow_bitmap); 912 g_free(s->in_flight_bitmap); 913 bdrv_dirty_iter_free(s->dbi); 914 915 data = g_malloc(sizeof(*data)); 916 data->ret = ret; 917 918 if (need_drain) { 919 bdrv_drained_begin(bs); 920 } 921 block_job_defer_to_main_loop(&s->common, mirror_exit, data); 922 } 923 924 static void mirror_set_speed(BlockJob *job, int64_t speed, Error **errp) 925 { 926 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 927 928 if (speed < 0) { 929 error_setg(errp, QERR_INVALID_PARAMETER, "speed"); 930 return; 931 } 932 ratelimit_set_speed(&s->limit, speed / BDRV_SECTOR_SIZE, SLICE_TIME); 933 } 934 935 static void mirror_complete(BlockJob *job, Error **errp) 936 { 937 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 938 BlockDriverState *target; 939 940 target = blk_bs(s->target); 941 942 if (!s->synced) { 943 error_setg(errp, "The active block job '%s' cannot be completed", 944 job->id); 945 return; 946 } 947 948 if (s->backing_mode == MIRROR_OPEN_BACKING_CHAIN) { 949 int ret; 950 951 assert(!target->backing); 952 ret = bdrv_open_backing_file(target, NULL, "backing", errp); 953 if (ret < 0) { 954 return; 955 } 956 } 957 958 /* block all operations on to_replace bs */ 959 if (s->replaces) { 960 AioContext *replace_aio_context; 961 962 s->to_replace = bdrv_find_node(s->replaces); 963 if (!s->to_replace) { 964 error_setg(errp, "Node name '%s' not found", s->replaces); 965 return; 966 } 967 968 replace_aio_context = bdrv_get_aio_context(s->to_replace); 969 aio_context_acquire(replace_aio_context); 970 971 /* TODO Translate this into permission system. Current definition of 972 * GRAPH_MOD would require to request it for the parents; they might 973 * not even be BlockDriverStates, however, so a BdrvChild can't address 974 * them. May need redefinition of GRAPH_MOD. */ 975 error_setg(&s->replace_blocker, 976 "block device is in use by block-job-complete"); 977 bdrv_op_block_all(s->to_replace, s->replace_blocker); 978 bdrv_ref(s->to_replace); 979 980 aio_context_release(replace_aio_context); 981 } 982 983 s->should_complete = true; 984 block_job_enter(&s->common); 985 } 986 987 static void mirror_pause(BlockJob *job) 988 { 989 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 990 991 mirror_wait_for_all_io(s); 992 } 993 994 static void mirror_attached_aio_context(BlockJob *job, AioContext *new_context) 995 { 996 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 997 998 blk_set_aio_context(s->target, new_context); 999 } 1000 1001 static void mirror_drain(BlockJob *job) 1002 { 1003 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 1004 1005 /* Need to keep a reference in case blk_drain triggers execution 1006 * of mirror_complete... 1007 */ 1008 if (s->target) { 1009 BlockBackend *target = s->target; 1010 blk_ref(target); 1011 blk_drain(target); 1012 blk_unref(target); 1013 } 1014 } 1015 1016 static const BlockJobDriver mirror_job_driver = { 1017 .instance_size = sizeof(MirrorBlockJob), 1018 .job_type = BLOCK_JOB_TYPE_MIRROR, 1019 .set_speed = mirror_set_speed, 1020 .start = mirror_run, 1021 .complete = mirror_complete, 1022 .pause = mirror_pause, 1023 .attached_aio_context = mirror_attached_aio_context, 1024 .drain = mirror_drain, 1025 }; 1026 1027 static const BlockJobDriver commit_active_job_driver = { 1028 .instance_size = sizeof(MirrorBlockJob), 1029 .job_type = BLOCK_JOB_TYPE_COMMIT, 1030 .set_speed = mirror_set_speed, 1031 .start = mirror_run, 1032 .complete = mirror_complete, 1033 .pause = mirror_pause, 1034 .attached_aio_context = mirror_attached_aio_context, 1035 .drain = mirror_drain, 1036 }; 1037 1038 static int coroutine_fn bdrv_mirror_top_preadv(BlockDriverState *bs, 1039 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags) 1040 { 1041 return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags); 1042 } 1043 1044 static int coroutine_fn bdrv_mirror_top_pwritev(BlockDriverState *bs, 1045 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags) 1046 { 1047 return bdrv_co_pwritev(bs->backing, offset, bytes, qiov, flags); 1048 } 1049 1050 static int coroutine_fn bdrv_mirror_top_flush(BlockDriverState *bs) 1051 { 1052 return bdrv_co_flush(bs->backing->bs); 1053 } 1054 1055 static int64_t coroutine_fn bdrv_mirror_top_get_block_status( 1056 BlockDriverState *bs, int64_t sector_num, int nb_sectors, int *pnum, 1057 BlockDriverState **file) 1058 { 1059 *pnum = nb_sectors; 1060 *file = bs->backing->bs; 1061 return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID | BDRV_BLOCK_DATA | 1062 (sector_num << BDRV_SECTOR_BITS); 1063 } 1064 1065 static int coroutine_fn bdrv_mirror_top_pwrite_zeroes(BlockDriverState *bs, 1066 int64_t offset, int bytes, BdrvRequestFlags flags) 1067 { 1068 return bdrv_co_pwrite_zeroes(bs->backing, offset, bytes, flags); 1069 } 1070 1071 static int coroutine_fn bdrv_mirror_top_pdiscard(BlockDriverState *bs, 1072 int64_t offset, int bytes) 1073 { 1074 return bdrv_co_pdiscard(bs->backing->bs, offset, bytes); 1075 } 1076 1077 static void bdrv_mirror_top_refresh_filename(BlockDriverState *bs, QDict *opts) 1078 { 1079 bdrv_refresh_filename(bs->backing->bs); 1080 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), 1081 bs->backing->bs->filename); 1082 } 1083 1084 static void bdrv_mirror_top_close(BlockDriverState *bs) 1085 { 1086 } 1087 1088 static void bdrv_mirror_top_child_perm(BlockDriverState *bs, BdrvChild *c, 1089 const BdrvChildRole *role, 1090 uint64_t perm, uint64_t shared, 1091 uint64_t *nperm, uint64_t *nshared) 1092 { 1093 /* Must be able to forward guest writes to the real image */ 1094 *nperm = 0; 1095 if (perm & BLK_PERM_WRITE) { 1096 *nperm |= BLK_PERM_WRITE; 1097 } 1098 1099 *nshared = BLK_PERM_ALL; 1100 } 1101 1102 /* Dummy node that provides consistent read to its users without requiring it 1103 * from its backing file and that allows writes on the backing file chain. */ 1104 static BlockDriver bdrv_mirror_top = { 1105 .format_name = "mirror_top", 1106 .bdrv_co_preadv = bdrv_mirror_top_preadv, 1107 .bdrv_co_pwritev = bdrv_mirror_top_pwritev, 1108 .bdrv_co_pwrite_zeroes = bdrv_mirror_top_pwrite_zeroes, 1109 .bdrv_co_pdiscard = bdrv_mirror_top_pdiscard, 1110 .bdrv_co_flush = bdrv_mirror_top_flush, 1111 .bdrv_co_get_block_status = bdrv_mirror_top_get_block_status, 1112 .bdrv_refresh_filename = bdrv_mirror_top_refresh_filename, 1113 .bdrv_close = bdrv_mirror_top_close, 1114 .bdrv_child_perm = bdrv_mirror_top_child_perm, 1115 }; 1116 1117 static void mirror_start_job(const char *job_id, BlockDriverState *bs, 1118 int creation_flags, BlockDriverState *target, 1119 const char *replaces, int64_t speed, 1120 uint32_t granularity, int64_t buf_size, 1121 BlockMirrorBackingMode backing_mode, 1122 BlockdevOnError on_source_error, 1123 BlockdevOnError on_target_error, 1124 bool unmap, 1125 BlockCompletionFunc *cb, 1126 void *opaque, 1127 const BlockJobDriver *driver, 1128 bool is_none_mode, BlockDriverState *base, 1129 bool auto_complete, const char *filter_node_name, 1130 Error **errp) 1131 { 1132 MirrorBlockJob *s; 1133 BlockDriverState *mirror_top_bs; 1134 bool target_graph_mod; 1135 bool target_is_backing; 1136 Error *local_err = NULL; 1137 int ret; 1138 1139 if (granularity == 0) { 1140 granularity = bdrv_get_default_bitmap_granularity(target); 1141 } 1142 1143 assert ((granularity & (granularity - 1)) == 0); 1144 1145 if (buf_size < 0) { 1146 error_setg(errp, "Invalid parameter 'buf-size'"); 1147 return; 1148 } 1149 1150 if (buf_size == 0) { 1151 buf_size = DEFAULT_MIRROR_BUF_SIZE; 1152 } 1153 1154 /* In the case of active commit, add dummy driver to provide consistent 1155 * reads on the top, while disabling it in the intermediate nodes, and make 1156 * the backing chain writable. */ 1157 mirror_top_bs = bdrv_new_open_driver(&bdrv_mirror_top, filter_node_name, 1158 BDRV_O_RDWR, errp); 1159 if (mirror_top_bs == NULL) { 1160 return; 1161 } 1162 mirror_top_bs->total_sectors = bs->total_sectors; 1163 bdrv_set_aio_context(mirror_top_bs, bdrv_get_aio_context(bs)); 1164 1165 /* bdrv_append takes ownership of the mirror_top_bs reference, need to keep 1166 * it alive until block_job_create() succeeds even if bs has no parent. */ 1167 bdrv_ref(mirror_top_bs); 1168 bdrv_drained_begin(bs); 1169 bdrv_append(mirror_top_bs, bs, &local_err); 1170 bdrv_drained_end(bs); 1171 1172 if (local_err) { 1173 bdrv_unref(mirror_top_bs); 1174 error_propagate(errp, local_err); 1175 return; 1176 } 1177 1178 /* Make sure that the source is not resized while the job is running */ 1179 s = block_job_create(job_id, driver, mirror_top_bs, 1180 BLK_PERM_CONSISTENT_READ, 1181 BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED | 1182 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD, speed, 1183 creation_flags, cb, opaque, errp); 1184 if (!s) { 1185 goto fail; 1186 } 1187 /* The block job now has a reference to this node */ 1188 bdrv_unref(mirror_top_bs); 1189 1190 s->source = bs; 1191 s->mirror_top_bs = mirror_top_bs; 1192 1193 /* No resize for the target either; while the mirror is still running, a 1194 * consistent read isn't necessarily possible. We could possibly allow 1195 * writes and graph modifications, though it would likely defeat the 1196 * purpose of a mirror, so leave them blocked for now. 1197 * 1198 * In the case of active commit, things look a bit different, though, 1199 * because the target is an already populated backing file in active use. 1200 * We can allow anything except resize there.*/ 1201 target_is_backing = bdrv_chain_contains(bs, target); 1202 target_graph_mod = (backing_mode != MIRROR_LEAVE_BACKING_CHAIN); 1203 s->target = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE | 1204 (target_graph_mod ? BLK_PERM_GRAPH_MOD : 0), 1205 BLK_PERM_WRITE_UNCHANGED | 1206 (target_is_backing ? BLK_PERM_CONSISTENT_READ | 1207 BLK_PERM_WRITE | 1208 BLK_PERM_GRAPH_MOD : 0)); 1209 ret = blk_insert_bs(s->target, target, errp); 1210 if (ret < 0) { 1211 goto fail; 1212 } 1213 1214 s->replaces = g_strdup(replaces); 1215 s->on_source_error = on_source_error; 1216 s->on_target_error = on_target_error; 1217 s->is_none_mode = is_none_mode; 1218 s->backing_mode = backing_mode; 1219 s->base = base; 1220 s->granularity = granularity; 1221 s->buf_size = ROUND_UP(buf_size, granularity); 1222 s->unmap = unmap; 1223 if (auto_complete) { 1224 s->should_complete = true; 1225 } 1226 1227 s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp); 1228 if (!s->dirty_bitmap) { 1229 goto fail; 1230 } 1231 1232 /* Required permissions are already taken with blk_new() */ 1233 block_job_add_bdrv(&s->common, "target", target, 0, BLK_PERM_ALL, 1234 &error_abort); 1235 1236 /* In commit_active_start() all intermediate nodes disappear, so 1237 * any jobs in them must be blocked */ 1238 if (target_is_backing) { 1239 BlockDriverState *iter; 1240 for (iter = backing_bs(bs); iter != target; iter = backing_bs(iter)) { 1241 /* XXX BLK_PERM_WRITE needs to be allowed so we don't block 1242 * ourselves at s->base (if writes are blocked for a node, they are 1243 * also blocked for its backing file). The other options would be a 1244 * second filter driver above s->base (== target). */ 1245 ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0, 1246 BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE, 1247 errp); 1248 if (ret < 0) { 1249 goto fail; 1250 } 1251 } 1252 } 1253 1254 trace_mirror_start(bs, s, opaque); 1255 block_job_start(&s->common); 1256 return; 1257 1258 fail: 1259 if (s) { 1260 /* Make sure this BDS does not go away until we have completed the graph 1261 * changes below */ 1262 bdrv_ref(mirror_top_bs); 1263 1264 g_free(s->replaces); 1265 blk_unref(s->target); 1266 block_job_early_fail(&s->common); 1267 } 1268 1269 bdrv_child_try_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL, 1270 &error_abort); 1271 bdrv_replace_node(mirror_top_bs, backing_bs(mirror_top_bs), &error_abort); 1272 1273 bdrv_unref(mirror_top_bs); 1274 } 1275 1276 void mirror_start(const char *job_id, BlockDriverState *bs, 1277 BlockDriverState *target, const char *replaces, 1278 int64_t speed, uint32_t granularity, int64_t buf_size, 1279 MirrorSyncMode mode, BlockMirrorBackingMode backing_mode, 1280 BlockdevOnError on_source_error, 1281 BlockdevOnError on_target_error, 1282 bool unmap, const char *filter_node_name, Error **errp) 1283 { 1284 bool is_none_mode; 1285 BlockDriverState *base; 1286 1287 if (mode == MIRROR_SYNC_MODE_INCREMENTAL) { 1288 error_setg(errp, "Sync mode 'incremental' not supported"); 1289 return; 1290 } 1291 is_none_mode = mode == MIRROR_SYNC_MODE_NONE; 1292 base = mode == MIRROR_SYNC_MODE_TOP ? backing_bs(bs) : NULL; 1293 mirror_start_job(job_id, bs, BLOCK_JOB_DEFAULT, target, replaces, 1294 speed, granularity, buf_size, backing_mode, 1295 on_source_error, on_target_error, unmap, NULL, NULL, 1296 &mirror_job_driver, is_none_mode, base, false, 1297 filter_node_name, errp); 1298 } 1299 1300 void commit_active_start(const char *job_id, BlockDriverState *bs, 1301 BlockDriverState *base, int creation_flags, 1302 int64_t speed, BlockdevOnError on_error, 1303 const char *filter_node_name, 1304 BlockCompletionFunc *cb, void *opaque, 1305 bool auto_complete, Error **errp) 1306 { 1307 int orig_base_flags; 1308 Error *local_err = NULL; 1309 1310 orig_base_flags = bdrv_get_flags(base); 1311 1312 if (bdrv_reopen(base, bs->open_flags, errp)) { 1313 return; 1314 } 1315 1316 mirror_start_job(job_id, bs, creation_flags, base, NULL, speed, 0, 0, 1317 MIRROR_LEAVE_BACKING_CHAIN, 1318 on_error, on_error, true, cb, opaque, 1319 &commit_active_job_driver, false, base, auto_complete, 1320 filter_node_name, &local_err); 1321 if (local_err) { 1322 error_propagate(errp, local_err); 1323 goto error_restore_flags; 1324 } 1325 1326 return; 1327 1328 error_restore_flags: 1329 /* ignore error and errp for bdrv_reopen, because we want to propagate 1330 * the original error */ 1331 bdrv_reopen(base, orig_base_flags, NULL); 1332 return; 1333 } 1334