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_BYTES (1 << 20) /* 1 Mb */ 28 #define DEFAULT_MIRROR_BUF_SIZE (MAX_IN_FLIGHT * MAX_IO_BYTES) 29 30 /* The mirroring buffer is a list of granularity-sized chunks. 31 * Free chunks are organized in a list. 32 */ 33 typedef struct MirrorBuffer { 34 QSIMPLEQ_ENTRY(MirrorBuffer) next; 35 } MirrorBuffer; 36 37 typedef struct MirrorBlockJob { 38 BlockJob common; 39 RateLimit limit; 40 BlockBackend *target; 41 BlockDriverState *mirror_top_bs; 42 BlockDriverState *source; 43 BlockDriverState *base; 44 45 /* The name of the graph node to replace */ 46 char *replaces; 47 /* The BDS to replace */ 48 BlockDriverState *to_replace; 49 /* Used to block operations on the drive-mirror-replace target */ 50 Error *replace_blocker; 51 bool is_none_mode; 52 BlockMirrorBackingMode backing_mode; 53 BlockdevOnError on_source_error, on_target_error; 54 bool synced; 55 bool should_complete; 56 int64_t granularity; 57 size_t buf_size; 58 int64_t bdev_length; 59 unsigned long *cow_bitmap; 60 BdrvDirtyBitmap *dirty_bitmap; 61 BdrvDirtyBitmapIter *dbi; 62 uint8_t *buf; 63 QSIMPLEQ_HEAD(, MirrorBuffer) buf_free; 64 int buf_free_count; 65 66 uint64_t last_pause_ns; 67 unsigned long *in_flight_bitmap; 68 int in_flight; 69 int64_t bytes_in_flight; 70 int ret; 71 bool unmap; 72 bool waiting_for_io; 73 int target_cluster_size; 74 int max_iov; 75 bool initial_zeroing_ongoing; 76 } MirrorBlockJob; 77 78 typedef struct MirrorOp { 79 MirrorBlockJob *s; 80 QEMUIOVector qiov; 81 int64_t offset; 82 uint64_t bytes; 83 } MirrorOp; 84 85 static BlockErrorAction mirror_error_action(MirrorBlockJob *s, bool read, 86 int error) 87 { 88 s->synced = false; 89 if (read) { 90 return block_job_error_action(&s->common, s->on_source_error, 91 true, error); 92 } else { 93 return block_job_error_action(&s->common, s->on_target_error, 94 false, error); 95 } 96 } 97 98 static void mirror_iteration_done(MirrorOp *op, int ret) 99 { 100 MirrorBlockJob *s = op->s; 101 struct iovec *iov; 102 int64_t chunk_num; 103 int i, nb_chunks; 104 105 trace_mirror_iteration_done(s, op->offset, op->bytes, ret); 106 107 s->in_flight--; 108 s->bytes_in_flight -= op->bytes; 109 iov = op->qiov.iov; 110 for (i = 0; i < op->qiov.niov; i++) { 111 MirrorBuffer *buf = (MirrorBuffer *) iov[i].iov_base; 112 QSIMPLEQ_INSERT_TAIL(&s->buf_free, buf, next); 113 s->buf_free_count++; 114 } 115 116 chunk_num = op->offset / s->granularity; 117 nb_chunks = DIV_ROUND_UP(op->bytes, s->granularity); 118 bitmap_clear(s->in_flight_bitmap, chunk_num, nb_chunks); 119 if (ret >= 0) { 120 if (s->cow_bitmap) { 121 bitmap_set(s->cow_bitmap, chunk_num, nb_chunks); 122 } 123 if (!s->initial_zeroing_ongoing) { 124 s->common.offset += op->bytes; 125 } 126 } 127 qemu_iovec_destroy(&op->qiov); 128 g_free(op); 129 130 if (s->waiting_for_io) { 131 qemu_coroutine_enter(s->common.co); 132 } 133 } 134 135 static void mirror_write_complete(void *opaque, int ret) 136 { 137 MirrorOp *op = opaque; 138 MirrorBlockJob *s = op->s; 139 140 aio_context_acquire(blk_get_aio_context(s->common.blk)); 141 if (ret < 0) { 142 BlockErrorAction action; 143 144 bdrv_set_dirty_bitmap(s->dirty_bitmap, op->offset >> BDRV_SECTOR_BITS, 145 op->bytes >> BDRV_SECTOR_BITS); 146 action = mirror_error_action(s, false, -ret); 147 if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) { 148 s->ret = ret; 149 } 150 } 151 mirror_iteration_done(op, ret); 152 aio_context_release(blk_get_aio_context(s->common.blk)); 153 } 154 155 static void mirror_read_complete(void *opaque, int ret) 156 { 157 MirrorOp *op = opaque; 158 MirrorBlockJob *s = op->s; 159 160 aio_context_acquire(blk_get_aio_context(s->common.blk)); 161 if (ret < 0) { 162 BlockErrorAction action; 163 164 bdrv_set_dirty_bitmap(s->dirty_bitmap, op->offset >> BDRV_SECTOR_BITS, 165 op->bytes >> BDRV_SECTOR_BITS); 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->offset, &op->qiov, 174 0, mirror_write_complete, op); 175 } 176 aio_context_release(blk_get_aio_context(s->common.blk)); 177 } 178 179 /* Clip bytes relative to offset to not exceed end-of-file */ 180 static inline int64_t mirror_clip_bytes(MirrorBlockJob *s, 181 int64_t offset, 182 int64_t bytes) 183 { 184 return MIN(bytes, s->bdev_length - offset); 185 } 186 187 /* Round offset and/or bytes to target cluster if COW is needed, and 188 * return the offset of the adjusted tail against original. */ 189 static int mirror_cow_align(MirrorBlockJob *s, int64_t *offset, 190 uint64_t *bytes) 191 { 192 bool need_cow; 193 int ret = 0; 194 int64_t align_offset = *offset; 195 unsigned int align_bytes = *bytes; 196 int max_bytes = s->granularity * s->max_iov; 197 198 assert(*bytes < INT_MAX); 199 need_cow = !test_bit(*offset / s->granularity, s->cow_bitmap); 200 need_cow |= !test_bit((*offset + *bytes - 1) / s->granularity, 201 s->cow_bitmap); 202 if (need_cow) { 203 bdrv_round_to_clusters(blk_bs(s->target), *offset, *bytes, 204 &align_offset, &align_bytes); 205 } 206 207 if (align_bytes > max_bytes) { 208 align_bytes = max_bytes; 209 if (need_cow) { 210 align_bytes = QEMU_ALIGN_DOWN(align_bytes, s->target_cluster_size); 211 } 212 } 213 /* Clipping may result in align_bytes unaligned to chunk boundary, but 214 * that doesn't matter because it's already the end of source image. */ 215 align_bytes = mirror_clip_bytes(s, align_offset, align_bytes); 216 217 ret = align_offset + align_bytes - (*offset + *bytes); 218 *offset = align_offset; 219 *bytes = align_bytes; 220 assert(ret >= 0); 221 return ret; 222 } 223 224 static inline void mirror_wait_for_io(MirrorBlockJob *s) 225 { 226 assert(!s->waiting_for_io); 227 s->waiting_for_io = true; 228 qemu_coroutine_yield(); 229 s->waiting_for_io = false; 230 } 231 232 /* Submit async read while handling COW. 233 * Returns: The number of bytes copied after and including offset, 234 * excluding any bytes copied prior to offset due to alignment. 235 * This will be @bytes if no alignment is necessary, or 236 * (new_end - offset) if tail is rounded up or down due to 237 * alignment or buffer limit. 238 */ 239 static uint64_t mirror_do_read(MirrorBlockJob *s, int64_t offset, 240 uint64_t bytes) 241 { 242 BlockBackend *source = s->common.blk; 243 int nb_chunks; 244 uint64_t ret; 245 MirrorOp *op; 246 uint64_t max_bytes; 247 248 max_bytes = s->granularity * s->max_iov; 249 250 /* We can only handle as much as buf_size at a time. */ 251 bytes = MIN(s->buf_size, MIN(max_bytes, bytes)); 252 assert(bytes); 253 assert(bytes < BDRV_REQUEST_MAX_BYTES); 254 ret = bytes; 255 256 if (s->cow_bitmap) { 257 ret += mirror_cow_align(s, &offset, &bytes); 258 } 259 assert(bytes <= s->buf_size); 260 /* The offset is granularity-aligned because: 261 * 1) Caller passes in aligned values; 262 * 2) mirror_cow_align is used only when target cluster is larger. */ 263 assert(QEMU_IS_ALIGNED(offset, s->granularity)); 264 /* The range is sector-aligned, since bdrv_getlength() rounds up. */ 265 assert(QEMU_IS_ALIGNED(bytes, BDRV_SECTOR_SIZE)); 266 nb_chunks = DIV_ROUND_UP(bytes, s->granularity); 267 268 while (s->buf_free_count < nb_chunks) { 269 trace_mirror_yield_in_flight(s, offset, s->in_flight); 270 mirror_wait_for_io(s); 271 } 272 273 /* Allocate a MirrorOp that is used as an AIO callback. */ 274 op = g_new(MirrorOp, 1); 275 op->s = s; 276 op->offset = offset; 277 op->bytes = bytes; 278 279 /* Now make a QEMUIOVector taking enough granularity-sized chunks 280 * from s->buf_free. 281 */ 282 qemu_iovec_init(&op->qiov, nb_chunks); 283 while (nb_chunks-- > 0) { 284 MirrorBuffer *buf = QSIMPLEQ_FIRST(&s->buf_free); 285 size_t remaining = bytes - 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 } 291 292 /* Copy the dirty cluster. */ 293 s->in_flight++; 294 s->bytes_in_flight += bytes; 295 trace_mirror_one_iteration(s, offset, bytes); 296 297 blk_aio_preadv(source, offset, &op->qiov, 0, mirror_read_complete, op); 298 return ret; 299 } 300 301 static void mirror_do_zero_or_discard(MirrorBlockJob *s, 302 int64_t offset, 303 uint64_t bytes, 304 bool is_discard) 305 { 306 MirrorOp *op; 307 308 /* Allocate a MirrorOp that is used as an AIO callback. The qiov is zeroed 309 * so the freeing in mirror_iteration_done is nop. */ 310 op = g_new0(MirrorOp, 1); 311 op->s = s; 312 op->offset = offset; 313 op->bytes = bytes; 314 315 s->in_flight++; 316 s->bytes_in_flight += bytes; 317 if (is_discard) { 318 blk_aio_pdiscard(s->target, offset, 319 op->bytes, mirror_write_complete, op); 320 } else { 321 blk_aio_pwrite_zeroes(s->target, offset, 322 op->bytes, s->unmap ? BDRV_REQ_MAY_UNMAP : 0, 323 mirror_write_complete, op); 324 } 325 } 326 327 static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) 328 { 329 BlockDriverState *source = s->source; 330 int64_t offset, first_chunk; 331 uint64_t delay_ns = 0; 332 /* At least the first dirty chunk is mirrored in one iteration. */ 333 int nb_chunks = 1; 334 int sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; 335 bool write_zeroes_ok = bdrv_can_write_zeroes_with_unmap(blk_bs(s->target)); 336 int max_io_bytes = MAX(s->buf_size / MAX_IN_FLIGHT, MAX_IO_BYTES); 337 338 bdrv_dirty_bitmap_lock(s->dirty_bitmap); 339 offset = bdrv_dirty_iter_next(s->dbi) * BDRV_SECTOR_SIZE; 340 if (offset < 0) { 341 bdrv_set_dirty_iter(s->dbi, 0); 342 offset = bdrv_dirty_iter_next(s->dbi) * BDRV_SECTOR_SIZE; 343 trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap) * 344 BDRV_SECTOR_SIZE); 345 assert(offset >= 0); 346 } 347 bdrv_dirty_bitmap_unlock(s->dirty_bitmap); 348 349 first_chunk = offset / s->granularity; 350 while (test_bit(first_chunk, s->in_flight_bitmap)) { 351 trace_mirror_yield_in_flight(s, offset, s->in_flight); 352 mirror_wait_for_io(s); 353 } 354 355 block_job_pause_point(&s->common); 356 357 /* Find the number of consective dirty chunks following the first dirty 358 * one, and wait for in flight requests in them. */ 359 bdrv_dirty_bitmap_lock(s->dirty_bitmap); 360 while (nb_chunks * s->granularity < s->buf_size) { 361 int64_t next_dirty; 362 int64_t next_offset = offset + nb_chunks * s->granularity; 363 int64_t next_chunk = next_offset / s->granularity; 364 if (next_offset >= s->bdev_length || 365 !bdrv_get_dirty_locked(source, s->dirty_bitmap, 366 next_offset >> BDRV_SECTOR_BITS)) { 367 break; 368 } 369 if (test_bit(next_chunk, s->in_flight_bitmap)) { 370 break; 371 } 372 373 next_dirty = bdrv_dirty_iter_next(s->dbi) * BDRV_SECTOR_SIZE; 374 if (next_dirty > next_offset || next_dirty < 0) { 375 /* The bitmap iterator's cache is stale, refresh it */ 376 bdrv_set_dirty_iter(s->dbi, next_offset >> BDRV_SECTOR_BITS); 377 next_dirty = bdrv_dirty_iter_next(s->dbi) * BDRV_SECTOR_SIZE; 378 } 379 assert(next_dirty == next_offset); 380 nb_chunks++; 381 } 382 383 /* Clear dirty bits before querying the block status, because 384 * calling bdrv_get_block_status_above could yield - if some blocks are 385 * marked dirty in this window, we need to know. 386 */ 387 bdrv_reset_dirty_bitmap_locked(s->dirty_bitmap, offset >> BDRV_SECTOR_BITS, 388 nb_chunks * sectors_per_chunk); 389 bdrv_dirty_bitmap_unlock(s->dirty_bitmap); 390 391 bitmap_set(s->in_flight_bitmap, offset / s->granularity, nb_chunks); 392 while (nb_chunks > 0 && offset < s->bdev_length) { 393 int64_t ret; 394 int io_sectors; 395 unsigned int io_bytes; 396 int64_t io_bytes_acct; 397 BlockDriverState *file; 398 enum MirrorMethod { 399 MIRROR_METHOD_COPY, 400 MIRROR_METHOD_ZERO, 401 MIRROR_METHOD_DISCARD 402 } mirror_method = MIRROR_METHOD_COPY; 403 404 assert(!(offset % s->granularity)); 405 ret = bdrv_get_block_status_above(source, NULL, 406 offset >> BDRV_SECTOR_BITS, 407 nb_chunks * sectors_per_chunk, 408 &io_sectors, &file); 409 io_bytes = io_sectors * BDRV_SECTOR_SIZE; 410 if (ret < 0) { 411 io_bytes = MIN(nb_chunks * s->granularity, max_io_bytes); 412 } else if (ret & BDRV_BLOCK_DATA) { 413 io_bytes = MIN(io_bytes, max_io_bytes); 414 } 415 416 io_bytes -= io_bytes % s->granularity; 417 if (io_bytes < s->granularity) { 418 io_bytes = s->granularity; 419 } else if (ret >= 0 && !(ret & BDRV_BLOCK_DATA)) { 420 int64_t target_offset; 421 unsigned int target_bytes; 422 bdrv_round_to_clusters(blk_bs(s->target), offset, io_bytes, 423 &target_offset, &target_bytes); 424 if (target_offset == offset && 425 target_bytes == io_bytes) { 426 mirror_method = ret & BDRV_BLOCK_ZERO ? 427 MIRROR_METHOD_ZERO : 428 MIRROR_METHOD_DISCARD; 429 } 430 } 431 432 while (s->in_flight >= MAX_IN_FLIGHT) { 433 trace_mirror_yield_in_flight(s, offset, s->in_flight); 434 mirror_wait_for_io(s); 435 } 436 437 if (s->ret < 0) { 438 return 0; 439 } 440 441 io_bytes = mirror_clip_bytes(s, offset, io_bytes); 442 switch (mirror_method) { 443 case MIRROR_METHOD_COPY: 444 io_bytes = io_bytes_acct = mirror_do_read(s, offset, io_bytes); 445 break; 446 case MIRROR_METHOD_ZERO: 447 case MIRROR_METHOD_DISCARD: 448 mirror_do_zero_or_discard(s, offset, io_bytes, 449 mirror_method == MIRROR_METHOD_DISCARD); 450 if (write_zeroes_ok) { 451 io_bytes_acct = 0; 452 } else { 453 io_bytes_acct = io_bytes; 454 } 455 break; 456 default: 457 abort(); 458 } 459 assert(io_bytes); 460 offset += io_bytes; 461 nb_chunks -= DIV_ROUND_UP(io_bytes, s->granularity); 462 if (s->common.speed) { 463 delay_ns = ratelimit_calculate_delay(&s->limit, io_bytes_acct); 464 } 465 } 466 return delay_ns; 467 } 468 469 static void mirror_free_init(MirrorBlockJob *s) 470 { 471 int granularity = s->granularity; 472 size_t buf_size = s->buf_size; 473 uint8_t *buf = s->buf; 474 475 assert(s->buf_free_count == 0); 476 QSIMPLEQ_INIT(&s->buf_free); 477 while (buf_size != 0) { 478 MirrorBuffer *cur = (MirrorBuffer *)buf; 479 QSIMPLEQ_INSERT_TAIL(&s->buf_free, cur, next); 480 s->buf_free_count++; 481 buf_size -= granularity; 482 buf += granularity; 483 } 484 } 485 486 /* This is also used for the .pause callback. There is no matching 487 * mirror_resume() because mirror_run() will begin iterating again 488 * when the job is resumed. 489 */ 490 static void mirror_wait_for_all_io(MirrorBlockJob *s) 491 { 492 while (s->in_flight > 0) { 493 mirror_wait_for_io(s); 494 } 495 } 496 497 typedef struct { 498 int ret; 499 } MirrorExitData; 500 501 static void mirror_exit(BlockJob *job, void *opaque) 502 { 503 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 504 MirrorExitData *data = opaque; 505 AioContext *replace_aio_context = NULL; 506 BlockDriverState *src = s->source; 507 BlockDriverState *target_bs = blk_bs(s->target); 508 BlockDriverState *mirror_top_bs = s->mirror_top_bs; 509 Error *local_err = NULL; 510 511 bdrv_release_dirty_bitmap(src, s->dirty_bitmap); 512 513 /* Make sure that the source BDS doesn't go away before we called 514 * block_job_completed(). */ 515 bdrv_ref(src); 516 bdrv_ref(mirror_top_bs); 517 bdrv_ref(target_bs); 518 519 /* Remove target parent that still uses BLK_PERM_WRITE/RESIZE before 520 * inserting target_bs at s->to_replace, where we might not be able to get 521 * these permissions. 522 * 523 * Note that blk_unref() alone doesn't necessarily drop permissions because 524 * we might be running nested inside mirror_drain(), which takes an extra 525 * reference, so use an explicit blk_set_perm() first. */ 526 blk_set_perm(s->target, 0, BLK_PERM_ALL, &error_abort); 527 blk_unref(s->target); 528 s->target = NULL; 529 530 /* We don't access the source any more. Dropping any WRITE/RESIZE is 531 * required before it could become a backing file of target_bs. */ 532 bdrv_child_try_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL, 533 &error_abort); 534 if (s->backing_mode == MIRROR_SOURCE_BACKING_CHAIN) { 535 BlockDriverState *backing = s->is_none_mode ? src : s->base; 536 if (backing_bs(target_bs) != backing) { 537 bdrv_set_backing_hd(target_bs, backing, &local_err); 538 if (local_err) { 539 error_report_err(local_err); 540 data->ret = -EPERM; 541 } 542 } 543 } 544 545 if (s->to_replace) { 546 replace_aio_context = bdrv_get_aio_context(s->to_replace); 547 aio_context_acquire(replace_aio_context); 548 } 549 550 if (s->should_complete && data->ret == 0) { 551 BlockDriverState *to_replace = src; 552 if (s->to_replace) { 553 to_replace = s->to_replace; 554 } 555 556 if (bdrv_get_flags(target_bs) != bdrv_get_flags(to_replace)) { 557 bdrv_reopen(target_bs, bdrv_get_flags(to_replace), NULL); 558 } 559 560 /* The mirror job has no requests in flight any more, but we need to 561 * drain potential other users of the BDS before changing the graph. */ 562 bdrv_drained_begin(target_bs); 563 bdrv_replace_node(to_replace, target_bs, &local_err); 564 bdrv_drained_end(target_bs); 565 if (local_err) { 566 error_report_err(local_err); 567 data->ret = -EPERM; 568 } 569 } 570 if (s->to_replace) { 571 bdrv_op_unblock_all(s->to_replace, s->replace_blocker); 572 error_free(s->replace_blocker); 573 bdrv_unref(s->to_replace); 574 } 575 if (replace_aio_context) { 576 aio_context_release(replace_aio_context); 577 } 578 g_free(s->replaces); 579 bdrv_unref(target_bs); 580 581 /* Remove the mirror filter driver from the graph. Before this, get rid of 582 * the blockers on the intermediate nodes so that the resulting state is 583 * valid. Also give up permissions on mirror_top_bs->backing, which might 584 * block the removal. */ 585 block_job_remove_all_bdrv(job); 586 bdrv_child_try_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL, 587 &error_abort); 588 bdrv_replace_node(mirror_top_bs, backing_bs(mirror_top_bs), &error_abort); 589 590 /* We just changed the BDS the job BB refers to (with either or both of the 591 * bdrv_replace_node() calls), so switch the BB back so the cleanup does 592 * the right thing. We don't need any permissions any more now. */ 593 blk_remove_bs(job->blk); 594 blk_set_perm(job->blk, 0, BLK_PERM_ALL, &error_abort); 595 blk_insert_bs(job->blk, mirror_top_bs, &error_abort); 596 597 block_job_completed(&s->common, data->ret); 598 599 g_free(data); 600 bdrv_drained_end(src); 601 bdrv_unref(mirror_top_bs); 602 bdrv_unref(src); 603 } 604 605 static void mirror_throttle(MirrorBlockJob *s) 606 { 607 int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 608 609 if (now - s->last_pause_ns > SLICE_TIME) { 610 s->last_pause_ns = now; 611 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, 0); 612 } else { 613 block_job_pause_point(&s->common); 614 } 615 } 616 617 static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s) 618 { 619 int64_t sector_num, end; 620 BlockDriverState *base = s->base; 621 BlockDriverState *bs = s->source; 622 BlockDriverState *target_bs = blk_bs(s->target); 623 int ret, n; 624 int64_t count; 625 626 end = s->bdev_length / BDRV_SECTOR_SIZE; 627 628 if (base == NULL && !bdrv_has_zero_init(target_bs)) { 629 if (!bdrv_can_write_zeroes_with_unmap(target_bs)) { 630 bdrv_set_dirty_bitmap(s->dirty_bitmap, 0, end); 631 return 0; 632 } 633 634 s->initial_zeroing_ongoing = true; 635 for (sector_num = 0; sector_num < end; ) { 636 int nb_sectors = MIN(end - sector_num, 637 QEMU_ALIGN_DOWN(INT_MAX, s->granularity) >> BDRV_SECTOR_BITS); 638 639 mirror_throttle(s); 640 641 if (block_job_is_cancelled(&s->common)) { 642 s->initial_zeroing_ongoing = false; 643 return 0; 644 } 645 646 if (s->in_flight >= MAX_IN_FLIGHT) { 647 trace_mirror_yield(s, UINT64_MAX, s->buf_free_count, 648 s->in_flight); 649 mirror_wait_for_io(s); 650 continue; 651 } 652 653 mirror_do_zero_or_discard(s, sector_num * BDRV_SECTOR_SIZE, 654 nb_sectors * BDRV_SECTOR_SIZE, false); 655 sector_num += nb_sectors; 656 } 657 658 mirror_wait_for_all_io(s); 659 s->initial_zeroing_ongoing = false; 660 } 661 662 /* First part, loop on the sectors and initialize the dirty bitmap. */ 663 for (sector_num = 0; sector_num < end; ) { 664 /* Just to make sure we are not exceeding int limit. */ 665 int nb_sectors = MIN(INT_MAX >> BDRV_SECTOR_BITS, 666 end - sector_num); 667 668 mirror_throttle(s); 669 670 if (block_job_is_cancelled(&s->common)) { 671 return 0; 672 } 673 674 ret = bdrv_is_allocated_above(bs, base, sector_num * BDRV_SECTOR_SIZE, 675 nb_sectors * BDRV_SECTOR_SIZE, &count); 676 if (ret < 0) { 677 return ret; 678 } 679 680 /* TODO: Relax this once bdrv_is_allocated_above and dirty 681 * bitmaps no longer require sector alignment. */ 682 assert(QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE)); 683 n = count >> BDRV_SECTOR_BITS; 684 assert(n > 0); 685 if (ret == 1) { 686 bdrv_set_dirty_bitmap(s->dirty_bitmap, sector_num, n); 687 } 688 sector_num += n; 689 } 690 return 0; 691 } 692 693 /* Called when going out of the streaming phase to flush the bulk of the 694 * data to the medium, or just before completing. 695 */ 696 static int mirror_flush(MirrorBlockJob *s) 697 { 698 int ret = blk_flush(s->target); 699 if (ret < 0) { 700 if (mirror_error_action(s, false, -ret) == BLOCK_ERROR_ACTION_REPORT) { 701 s->ret = ret; 702 } 703 } 704 return ret; 705 } 706 707 static void coroutine_fn mirror_run(void *opaque) 708 { 709 MirrorBlockJob *s = opaque; 710 MirrorExitData *data; 711 BlockDriverState *bs = s->source; 712 BlockDriverState *target_bs = blk_bs(s->target); 713 bool need_drain = true; 714 int64_t length; 715 BlockDriverInfo bdi; 716 char backing_filename[2]; /* we only need 2 characters because we are only 717 checking for a NULL string */ 718 int ret = 0; 719 720 if (block_job_is_cancelled(&s->common)) { 721 goto immediate_exit; 722 } 723 724 s->bdev_length = bdrv_getlength(bs); 725 if (s->bdev_length < 0) { 726 ret = s->bdev_length; 727 goto immediate_exit; 728 } 729 730 /* Active commit must resize the base image if its size differs from the 731 * active layer. */ 732 if (s->base == blk_bs(s->target)) { 733 int64_t base_length; 734 735 base_length = blk_getlength(s->target); 736 if (base_length < 0) { 737 ret = base_length; 738 goto immediate_exit; 739 } 740 741 if (s->bdev_length > base_length) { 742 ret = blk_truncate(s->target, s->bdev_length, NULL); 743 if (ret < 0) { 744 goto immediate_exit; 745 } 746 } 747 } 748 749 if (s->bdev_length == 0) { 750 /* Report BLOCK_JOB_READY and wait for complete. */ 751 block_job_event_ready(&s->common); 752 s->synced = true; 753 while (!block_job_is_cancelled(&s->common) && !s->should_complete) { 754 block_job_yield(&s->common); 755 } 756 s->common.cancelled = false; 757 goto immediate_exit; 758 } 759 760 length = DIV_ROUND_UP(s->bdev_length, s->granularity); 761 s->in_flight_bitmap = bitmap_new(length); 762 763 /* If we have no backing file yet in the destination, we cannot let 764 * the destination do COW. Instead, we copy sectors around the 765 * dirty data if needed. We need a bitmap to do that. 766 */ 767 bdrv_get_backing_filename(target_bs, backing_filename, 768 sizeof(backing_filename)); 769 if (!bdrv_get_info(target_bs, &bdi) && bdi.cluster_size) { 770 s->target_cluster_size = bdi.cluster_size; 771 } else { 772 s->target_cluster_size = BDRV_SECTOR_SIZE; 773 } 774 if (backing_filename[0] && !target_bs->backing && 775 s->granularity < s->target_cluster_size) { 776 s->buf_size = MAX(s->buf_size, s->target_cluster_size); 777 s->cow_bitmap = bitmap_new(length); 778 } 779 s->max_iov = MIN(bs->bl.max_iov, target_bs->bl.max_iov); 780 781 s->buf = qemu_try_blockalign(bs, s->buf_size); 782 if (s->buf == NULL) { 783 ret = -ENOMEM; 784 goto immediate_exit; 785 } 786 787 mirror_free_init(s); 788 789 s->last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 790 if (!s->is_none_mode) { 791 ret = mirror_dirty_init(s); 792 if (ret < 0 || block_job_is_cancelled(&s->common)) { 793 goto immediate_exit; 794 } 795 } 796 797 assert(!s->dbi); 798 s->dbi = bdrv_dirty_iter_new(s->dirty_bitmap, 0); 799 for (;;) { 800 uint64_t delay_ns = 0; 801 int64_t cnt, delta; 802 bool should_complete; 803 804 if (s->ret < 0) { 805 ret = s->ret; 806 goto immediate_exit; 807 } 808 809 block_job_pause_point(&s->common); 810 811 cnt = bdrv_get_dirty_count(s->dirty_bitmap); 812 /* s->common.offset contains the number of bytes already processed so 813 * far, cnt is the number of dirty sectors remaining and 814 * s->bytes_in_flight is the number of bytes currently being 815 * processed; together those are the current total operation length */ 816 s->common.len = s->common.offset + s->bytes_in_flight + 817 cnt * BDRV_SECTOR_SIZE; 818 819 /* Note that even when no rate limit is applied we need to yield 820 * periodically with no pending I/O so that bdrv_drain_all() returns. 821 * We do so every SLICE_TIME nanoseconds, or when there is an error, 822 * or when the source is clean, whichever comes first. 823 */ 824 delta = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - s->last_pause_ns; 825 if (delta < SLICE_TIME && 826 s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) { 827 if (s->in_flight >= MAX_IN_FLIGHT || s->buf_free_count == 0 || 828 (cnt == 0 && s->in_flight > 0)) { 829 trace_mirror_yield(s, cnt * BDRV_SECTOR_SIZE, 830 s->buf_free_count, s->in_flight); 831 mirror_wait_for_io(s); 832 continue; 833 } else if (cnt != 0) { 834 delay_ns = mirror_iteration(s); 835 } 836 } 837 838 should_complete = false; 839 if (s->in_flight == 0 && cnt == 0) { 840 trace_mirror_before_flush(s); 841 if (!s->synced) { 842 if (mirror_flush(s) < 0) { 843 /* Go check s->ret. */ 844 continue; 845 } 846 /* We're out of the streaming phase. From now on, if the job 847 * is cancelled we will actually complete all pending I/O and 848 * report completion. This way, block-job-cancel will leave 849 * the target in a consistent state. 850 */ 851 block_job_event_ready(&s->common); 852 s->synced = true; 853 } 854 855 should_complete = s->should_complete || 856 block_job_is_cancelled(&s->common); 857 cnt = bdrv_get_dirty_count(s->dirty_bitmap); 858 } 859 860 if (cnt == 0 && should_complete) { 861 /* The dirty bitmap is not updated while operations are pending. 862 * If we're about to exit, wait for pending operations before 863 * calling bdrv_get_dirty_count(bs), or we may exit while the 864 * source has dirty data to copy! 865 * 866 * Note that I/O can be submitted by the guest while 867 * mirror_populate runs, so pause it now. Before deciding 868 * whether to switch to target check one last time if I/O has 869 * come in the meanwhile, and if not flush the data to disk. 870 */ 871 trace_mirror_before_drain(s, cnt * BDRV_SECTOR_SIZE); 872 873 bdrv_drained_begin(bs); 874 cnt = bdrv_get_dirty_count(s->dirty_bitmap); 875 if (cnt > 0 || mirror_flush(s) < 0) { 876 bdrv_drained_end(bs); 877 continue; 878 } 879 880 /* The two disks are in sync. Exit and report successful 881 * completion. 882 */ 883 assert(QLIST_EMPTY(&bs->tracked_requests)); 884 s->common.cancelled = false; 885 need_drain = false; 886 break; 887 } 888 889 ret = 0; 890 trace_mirror_before_sleep(s, cnt * BDRV_SECTOR_SIZE, 891 s->synced, delay_ns); 892 if (!s->synced) { 893 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); 894 if (block_job_is_cancelled(&s->common)) { 895 break; 896 } 897 } else if (!should_complete) { 898 delay_ns = (s->in_flight == 0 && cnt == 0 ? SLICE_TIME : 0); 899 block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); 900 } 901 s->last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 902 } 903 904 immediate_exit: 905 if (s->in_flight > 0) { 906 /* We get here only if something went wrong. Either the job failed, 907 * or it was cancelled prematurely so that we do not guarantee that 908 * the target is a copy of the source. 909 */ 910 assert(ret < 0 || (!s->synced && block_job_is_cancelled(&s->common))); 911 assert(need_drain); 912 mirror_wait_for_all_io(s); 913 } 914 915 assert(s->in_flight == 0); 916 qemu_vfree(s->buf); 917 g_free(s->cow_bitmap); 918 g_free(s->in_flight_bitmap); 919 bdrv_dirty_iter_free(s->dbi); 920 921 data = g_malloc(sizeof(*data)); 922 data->ret = ret; 923 924 if (need_drain) { 925 bdrv_drained_begin(bs); 926 } 927 block_job_defer_to_main_loop(&s->common, mirror_exit, data); 928 } 929 930 static void mirror_set_speed(BlockJob *job, int64_t speed, Error **errp) 931 { 932 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 933 934 if (speed < 0) { 935 error_setg(errp, QERR_INVALID_PARAMETER, "speed"); 936 return; 937 } 938 ratelimit_set_speed(&s->limit, speed, SLICE_TIME); 939 } 940 941 static void mirror_complete(BlockJob *job, Error **errp) 942 { 943 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 944 BlockDriverState *target; 945 946 target = blk_bs(s->target); 947 948 if (!s->synced) { 949 error_setg(errp, "The active block job '%s' cannot be completed", 950 job->id); 951 return; 952 } 953 954 if (s->backing_mode == MIRROR_OPEN_BACKING_CHAIN) { 955 int ret; 956 957 assert(!target->backing); 958 ret = bdrv_open_backing_file(target, NULL, "backing", errp); 959 if (ret < 0) { 960 return; 961 } 962 } 963 964 /* block all operations on to_replace bs */ 965 if (s->replaces) { 966 AioContext *replace_aio_context; 967 968 s->to_replace = bdrv_find_node(s->replaces); 969 if (!s->to_replace) { 970 error_setg(errp, "Node name '%s' not found", s->replaces); 971 return; 972 } 973 974 replace_aio_context = bdrv_get_aio_context(s->to_replace); 975 aio_context_acquire(replace_aio_context); 976 977 /* TODO Translate this into permission system. Current definition of 978 * GRAPH_MOD would require to request it for the parents; they might 979 * not even be BlockDriverStates, however, so a BdrvChild can't address 980 * them. May need redefinition of GRAPH_MOD. */ 981 error_setg(&s->replace_blocker, 982 "block device is in use by block-job-complete"); 983 bdrv_op_block_all(s->to_replace, s->replace_blocker); 984 bdrv_ref(s->to_replace); 985 986 aio_context_release(replace_aio_context); 987 } 988 989 s->should_complete = true; 990 block_job_enter(&s->common); 991 } 992 993 static void mirror_pause(BlockJob *job) 994 { 995 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 996 997 mirror_wait_for_all_io(s); 998 } 999 1000 static void mirror_attached_aio_context(BlockJob *job, AioContext *new_context) 1001 { 1002 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 1003 1004 blk_set_aio_context(s->target, new_context); 1005 } 1006 1007 static void mirror_drain(BlockJob *job) 1008 { 1009 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 1010 1011 /* Need to keep a reference in case blk_drain triggers execution 1012 * of mirror_complete... 1013 */ 1014 if (s->target) { 1015 BlockBackend *target = s->target; 1016 blk_ref(target); 1017 blk_drain(target); 1018 blk_unref(target); 1019 } 1020 } 1021 1022 static const BlockJobDriver mirror_job_driver = { 1023 .instance_size = sizeof(MirrorBlockJob), 1024 .job_type = BLOCK_JOB_TYPE_MIRROR, 1025 .set_speed = mirror_set_speed, 1026 .start = mirror_run, 1027 .complete = mirror_complete, 1028 .pause = mirror_pause, 1029 .attached_aio_context = mirror_attached_aio_context, 1030 .drain = mirror_drain, 1031 }; 1032 1033 static const BlockJobDriver commit_active_job_driver = { 1034 .instance_size = sizeof(MirrorBlockJob), 1035 .job_type = BLOCK_JOB_TYPE_COMMIT, 1036 .set_speed = mirror_set_speed, 1037 .start = mirror_run, 1038 .complete = mirror_complete, 1039 .pause = mirror_pause, 1040 .attached_aio_context = mirror_attached_aio_context, 1041 .drain = mirror_drain, 1042 }; 1043 1044 static int coroutine_fn bdrv_mirror_top_preadv(BlockDriverState *bs, 1045 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags) 1046 { 1047 return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags); 1048 } 1049 1050 static int coroutine_fn bdrv_mirror_top_pwritev(BlockDriverState *bs, 1051 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags) 1052 { 1053 return bdrv_co_pwritev(bs->backing, offset, bytes, qiov, flags); 1054 } 1055 1056 static int coroutine_fn bdrv_mirror_top_flush(BlockDriverState *bs) 1057 { 1058 return bdrv_co_flush(bs->backing->bs); 1059 } 1060 1061 static int64_t coroutine_fn bdrv_mirror_top_get_block_status( 1062 BlockDriverState *bs, int64_t sector_num, int nb_sectors, int *pnum, 1063 BlockDriverState **file) 1064 { 1065 *pnum = nb_sectors; 1066 *file = bs->backing->bs; 1067 return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID | 1068 (sector_num << BDRV_SECTOR_BITS); 1069 } 1070 1071 static int coroutine_fn bdrv_mirror_top_pwrite_zeroes(BlockDriverState *bs, 1072 int64_t offset, int bytes, BdrvRequestFlags flags) 1073 { 1074 return bdrv_co_pwrite_zeroes(bs->backing, offset, bytes, flags); 1075 } 1076 1077 static int coroutine_fn bdrv_mirror_top_pdiscard(BlockDriverState *bs, 1078 int64_t offset, int bytes) 1079 { 1080 return bdrv_co_pdiscard(bs->backing->bs, offset, bytes); 1081 } 1082 1083 static void bdrv_mirror_top_refresh_filename(BlockDriverState *bs, QDict *opts) 1084 { 1085 bdrv_refresh_filename(bs->backing->bs); 1086 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), 1087 bs->backing->bs->filename); 1088 } 1089 1090 static void bdrv_mirror_top_close(BlockDriverState *bs) 1091 { 1092 } 1093 1094 static void bdrv_mirror_top_child_perm(BlockDriverState *bs, BdrvChild *c, 1095 const BdrvChildRole *role, 1096 uint64_t perm, uint64_t shared, 1097 uint64_t *nperm, uint64_t *nshared) 1098 { 1099 /* Must be able to forward guest writes to the real image */ 1100 *nperm = 0; 1101 if (perm & BLK_PERM_WRITE) { 1102 *nperm |= BLK_PERM_WRITE; 1103 } 1104 1105 *nshared = BLK_PERM_ALL; 1106 } 1107 1108 /* Dummy node that provides consistent read to its users without requiring it 1109 * from its backing file and that allows writes on the backing file chain. */ 1110 static BlockDriver bdrv_mirror_top = { 1111 .format_name = "mirror_top", 1112 .bdrv_co_preadv = bdrv_mirror_top_preadv, 1113 .bdrv_co_pwritev = bdrv_mirror_top_pwritev, 1114 .bdrv_co_pwrite_zeroes = bdrv_mirror_top_pwrite_zeroes, 1115 .bdrv_co_pdiscard = bdrv_mirror_top_pdiscard, 1116 .bdrv_co_flush = bdrv_mirror_top_flush, 1117 .bdrv_co_get_block_status = bdrv_mirror_top_get_block_status, 1118 .bdrv_refresh_filename = bdrv_mirror_top_refresh_filename, 1119 .bdrv_close = bdrv_mirror_top_close, 1120 .bdrv_child_perm = bdrv_mirror_top_child_perm, 1121 }; 1122 1123 static void mirror_start_job(const char *job_id, BlockDriverState *bs, 1124 int creation_flags, BlockDriverState *target, 1125 const char *replaces, int64_t speed, 1126 uint32_t granularity, int64_t buf_size, 1127 BlockMirrorBackingMode backing_mode, 1128 BlockdevOnError on_source_error, 1129 BlockdevOnError on_target_error, 1130 bool unmap, 1131 BlockCompletionFunc *cb, 1132 void *opaque, 1133 const BlockJobDriver *driver, 1134 bool is_none_mode, BlockDriverState *base, 1135 bool auto_complete, const char *filter_node_name, 1136 Error **errp) 1137 { 1138 MirrorBlockJob *s; 1139 BlockDriverState *mirror_top_bs; 1140 bool target_graph_mod; 1141 bool target_is_backing; 1142 Error *local_err = NULL; 1143 int ret; 1144 1145 if (granularity == 0) { 1146 granularity = bdrv_get_default_bitmap_granularity(target); 1147 } 1148 1149 assert ((granularity & (granularity - 1)) == 0); 1150 /* Granularity must be large enough for sector-based dirty bitmap */ 1151 assert(granularity >= BDRV_SECTOR_SIZE); 1152 1153 if (buf_size < 0) { 1154 error_setg(errp, "Invalid parameter 'buf-size'"); 1155 return; 1156 } 1157 1158 if (buf_size == 0) { 1159 buf_size = DEFAULT_MIRROR_BUF_SIZE; 1160 } 1161 1162 /* In the case of active commit, add dummy driver to provide consistent 1163 * reads on the top, while disabling it in the intermediate nodes, and make 1164 * the backing chain writable. */ 1165 mirror_top_bs = bdrv_new_open_driver(&bdrv_mirror_top, filter_node_name, 1166 BDRV_O_RDWR, errp); 1167 if (mirror_top_bs == NULL) { 1168 return; 1169 } 1170 mirror_top_bs->total_sectors = bs->total_sectors; 1171 bdrv_set_aio_context(mirror_top_bs, bdrv_get_aio_context(bs)); 1172 1173 /* bdrv_append takes ownership of the mirror_top_bs reference, need to keep 1174 * it alive until block_job_create() succeeds even if bs has no parent. */ 1175 bdrv_ref(mirror_top_bs); 1176 bdrv_drained_begin(bs); 1177 bdrv_append(mirror_top_bs, bs, &local_err); 1178 bdrv_drained_end(bs); 1179 1180 if (local_err) { 1181 bdrv_unref(mirror_top_bs); 1182 error_propagate(errp, local_err); 1183 return; 1184 } 1185 1186 /* Make sure that the source is not resized while the job is running */ 1187 s = block_job_create(job_id, driver, mirror_top_bs, 1188 BLK_PERM_CONSISTENT_READ, 1189 BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED | 1190 BLK_PERM_WRITE | BLK_PERM_GRAPH_MOD, speed, 1191 creation_flags, cb, opaque, errp); 1192 if (!s) { 1193 goto fail; 1194 } 1195 /* The block job now has a reference to this node */ 1196 bdrv_unref(mirror_top_bs); 1197 1198 s->source = bs; 1199 s->mirror_top_bs = mirror_top_bs; 1200 1201 /* No resize for the target either; while the mirror is still running, a 1202 * consistent read isn't necessarily possible. We could possibly allow 1203 * writes and graph modifications, though it would likely defeat the 1204 * purpose of a mirror, so leave them blocked for now. 1205 * 1206 * In the case of active commit, things look a bit different, though, 1207 * because the target is an already populated backing file in active use. 1208 * We can allow anything except resize there.*/ 1209 target_is_backing = bdrv_chain_contains(bs, target); 1210 target_graph_mod = (backing_mode != MIRROR_LEAVE_BACKING_CHAIN); 1211 s->target = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE | 1212 (target_graph_mod ? BLK_PERM_GRAPH_MOD : 0), 1213 BLK_PERM_WRITE_UNCHANGED | 1214 (target_is_backing ? BLK_PERM_CONSISTENT_READ | 1215 BLK_PERM_WRITE | 1216 BLK_PERM_GRAPH_MOD : 0)); 1217 ret = blk_insert_bs(s->target, target, errp); 1218 if (ret < 0) { 1219 goto fail; 1220 } 1221 1222 s->replaces = g_strdup(replaces); 1223 s->on_source_error = on_source_error; 1224 s->on_target_error = on_target_error; 1225 s->is_none_mode = is_none_mode; 1226 s->backing_mode = backing_mode; 1227 s->base = base; 1228 s->granularity = granularity; 1229 s->buf_size = ROUND_UP(buf_size, granularity); 1230 s->unmap = unmap; 1231 if (auto_complete) { 1232 s->should_complete = true; 1233 } 1234 1235 s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp); 1236 if (!s->dirty_bitmap) { 1237 goto fail; 1238 } 1239 1240 /* Required permissions are already taken with blk_new() */ 1241 block_job_add_bdrv(&s->common, "target", target, 0, BLK_PERM_ALL, 1242 &error_abort); 1243 1244 /* In commit_active_start() all intermediate nodes disappear, so 1245 * any jobs in them must be blocked */ 1246 if (target_is_backing) { 1247 BlockDriverState *iter; 1248 for (iter = backing_bs(bs); iter != target; iter = backing_bs(iter)) { 1249 /* XXX BLK_PERM_WRITE needs to be allowed so we don't block 1250 * ourselves at s->base (if writes are blocked for a node, they are 1251 * also blocked for its backing file). The other options would be a 1252 * second filter driver above s->base (== target). */ 1253 ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0, 1254 BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE, 1255 errp); 1256 if (ret < 0) { 1257 goto fail; 1258 } 1259 } 1260 } 1261 1262 trace_mirror_start(bs, s, opaque); 1263 block_job_start(&s->common); 1264 return; 1265 1266 fail: 1267 if (s) { 1268 /* Make sure this BDS does not go away until we have completed the graph 1269 * changes below */ 1270 bdrv_ref(mirror_top_bs); 1271 1272 g_free(s->replaces); 1273 blk_unref(s->target); 1274 block_job_early_fail(&s->common); 1275 } 1276 1277 bdrv_child_try_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL, 1278 &error_abort); 1279 bdrv_replace_node(mirror_top_bs, backing_bs(mirror_top_bs), &error_abort); 1280 1281 bdrv_unref(mirror_top_bs); 1282 } 1283 1284 void mirror_start(const char *job_id, BlockDriverState *bs, 1285 BlockDriverState *target, const char *replaces, 1286 int64_t speed, uint32_t granularity, int64_t buf_size, 1287 MirrorSyncMode mode, BlockMirrorBackingMode backing_mode, 1288 BlockdevOnError on_source_error, 1289 BlockdevOnError on_target_error, 1290 bool unmap, const char *filter_node_name, Error **errp) 1291 { 1292 bool is_none_mode; 1293 BlockDriverState *base; 1294 1295 if (mode == MIRROR_SYNC_MODE_INCREMENTAL) { 1296 error_setg(errp, "Sync mode 'incremental' not supported"); 1297 return; 1298 } 1299 is_none_mode = mode == MIRROR_SYNC_MODE_NONE; 1300 base = mode == MIRROR_SYNC_MODE_TOP ? backing_bs(bs) : NULL; 1301 mirror_start_job(job_id, bs, BLOCK_JOB_DEFAULT, target, replaces, 1302 speed, granularity, buf_size, backing_mode, 1303 on_source_error, on_target_error, unmap, NULL, NULL, 1304 &mirror_job_driver, is_none_mode, base, false, 1305 filter_node_name, errp); 1306 } 1307 1308 void commit_active_start(const char *job_id, BlockDriverState *bs, 1309 BlockDriverState *base, int creation_flags, 1310 int64_t speed, BlockdevOnError on_error, 1311 const char *filter_node_name, 1312 BlockCompletionFunc *cb, void *opaque, 1313 bool auto_complete, Error **errp) 1314 { 1315 int orig_base_flags; 1316 Error *local_err = NULL; 1317 1318 orig_base_flags = bdrv_get_flags(base); 1319 1320 if (bdrv_reopen(base, bs->open_flags, errp)) { 1321 return; 1322 } 1323 1324 mirror_start_job(job_id, bs, creation_flags, base, NULL, speed, 0, 0, 1325 MIRROR_LEAVE_BACKING_CHAIN, 1326 on_error, on_error, true, cb, opaque, 1327 &commit_active_job_driver, false, base, auto_complete, 1328 filter_node_name, &local_err); 1329 if (local_err) { 1330 error_propagate(errp, local_err); 1331 goto error_restore_flags; 1332 } 1333 1334 return; 1335 1336 error_restore_flags: 1337 /* ignore error and errp for bdrv_reopen, because we want to propagate 1338 * the original error */ 1339 bdrv_reopen(base, orig_base_flags, NULL); 1340 return; 1341 } 1342