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 "qemu/coroutine.h" 17 #include "qemu/range.h" 18 #include "trace.h" 19 #include "block/blockjob_int.h" 20 #include "block/block_int.h" 21 #include "block/dirty-bitmap.h" 22 #include "sysemu/block-backend.h" 23 #include "qapi/error.h" 24 #include "qemu/ratelimit.h" 25 #include "qemu/bitmap.h" 26 #include "qemu/memalign.h" 27 28 #define MAX_IN_FLIGHT 16 29 #define MAX_IO_BYTES (1 << 20) /* 1 Mb */ 30 #define DEFAULT_MIRROR_BUF_SIZE (MAX_IN_FLIGHT * MAX_IO_BYTES) 31 32 /* The mirroring buffer is a list of granularity-sized chunks. 33 * Free chunks are organized in a list. 34 */ 35 typedef struct MirrorBuffer { 36 QSIMPLEQ_ENTRY(MirrorBuffer) next; 37 } MirrorBuffer; 38 39 typedef struct MirrorOp MirrorOp; 40 41 typedef struct MirrorBlockJob { 42 BlockJob common; 43 BlockBackend *target; 44 BlockDriverState *mirror_top_bs; 45 BlockDriverState *base; 46 BlockDriverState *base_overlay; 47 48 /* The name of the graph node to replace */ 49 char *replaces; 50 /* The BDS to replace */ 51 BlockDriverState *to_replace; 52 /* Used to block operations on the drive-mirror-replace target */ 53 Error *replace_blocker; 54 bool is_none_mode; 55 BlockMirrorBackingMode backing_mode; 56 /* Whether the target image requires explicit zero-initialization */ 57 bool zero_target; 58 MirrorCopyMode copy_mode; 59 BlockdevOnError on_source_error, on_target_error; 60 /* Set when the target is synced (dirty bitmap is clean, nothing 61 * in flight) and the job is running in active mode */ 62 bool actively_synced; 63 bool should_complete; 64 int64_t granularity; 65 size_t buf_size; 66 int64_t bdev_length; 67 unsigned long *cow_bitmap; 68 BdrvDirtyBitmap *dirty_bitmap; 69 BdrvDirtyBitmapIter *dbi; 70 uint8_t *buf; 71 QSIMPLEQ_HEAD(, MirrorBuffer) buf_free; 72 int buf_free_count; 73 74 uint64_t last_pause_ns; 75 unsigned long *in_flight_bitmap; 76 unsigned in_flight; 77 int64_t bytes_in_flight; 78 QTAILQ_HEAD(, MirrorOp) ops_in_flight; 79 int ret; 80 bool unmap; 81 int target_cluster_size; 82 int max_iov; 83 bool initial_zeroing_ongoing; 84 int in_active_write_counter; 85 int64_t active_write_bytes_in_flight; 86 bool prepared; 87 bool in_drain; 88 } MirrorBlockJob; 89 90 typedef struct MirrorBDSOpaque { 91 MirrorBlockJob *job; 92 bool stop; 93 bool is_commit; 94 } MirrorBDSOpaque; 95 96 struct MirrorOp { 97 MirrorBlockJob *s; 98 QEMUIOVector qiov; 99 int64_t offset; 100 uint64_t bytes; 101 102 /* The pointee is set by mirror_co_read(), mirror_co_zero(), and 103 * mirror_co_discard() before yielding for the first time */ 104 int64_t *bytes_handled; 105 106 bool is_pseudo_op; 107 bool is_active_write; 108 bool is_in_flight; 109 CoQueue waiting_requests; 110 Coroutine *co; 111 MirrorOp *waiting_for_op; 112 113 QTAILQ_ENTRY(MirrorOp) next; 114 }; 115 116 typedef enum MirrorMethod { 117 MIRROR_METHOD_COPY, 118 MIRROR_METHOD_ZERO, 119 MIRROR_METHOD_DISCARD, 120 } MirrorMethod; 121 122 static BlockErrorAction mirror_error_action(MirrorBlockJob *s, bool read, 123 int error) 124 { 125 s->actively_synced = false; 126 if (read) { 127 return block_job_error_action(&s->common, s->on_source_error, 128 true, error); 129 } else { 130 return block_job_error_action(&s->common, s->on_target_error, 131 false, error); 132 } 133 } 134 135 static void coroutine_fn mirror_wait_on_conflicts(MirrorOp *self, 136 MirrorBlockJob *s, 137 uint64_t offset, 138 uint64_t bytes) 139 { 140 uint64_t self_start_chunk = offset / s->granularity; 141 uint64_t self_end_chunk = DIV_ROUND_UP(offset + bytes, s->granularity); 142 uint64_t self_nb_chunks = self_end_chunk - self_start_chunk; 143 144 while (find_next_bit(s->in_flight_bitmap, self_end_chunk, 145 self_start_chunk) < self_end_chunk && 146 s->ret >= 0) 147 { 148 MirrorOp *op; 149 150 QTAILQ_FOREACH(op, &s->ops_in_flight, next) { 151 uint64_t op_start_chunk = op->offset / s->granularity; 152 uint64_t op_nb_chunks = DIV_ROUND_UP(op->offset + op->bytes, 153 s->granularity) - 154 op_start_chunk; 155 156 if (op == self) { 157 continue; 158 } 159 160 if (ranges_overlap(self_start_chunk, self_nb_chunks, 161 op_start_chunk, op_nb_chunks)) 162 { 163 if (self) { 164 /* 165 * If the operation is already (indirectly) waiting for us, 166 * or will wait for us as soon as it wakes up, then just go 167 * on (instead of producing a deadlock in the former case). 168 */ 169 if (op->waiting_for_op) { 170 continue; 171 } 172 173 self->waiting_for_op = op; 174 } 175 176 qemu_co_queue_wait(&op->waiting_requests, NULL); 177 178 if (self) { 179 self->waiting_for_op = NULL; 180 } 181 182 break; 183 } 184 } 185 } 186 } 187 188 static void coroutine_fn mirror_iteration_done(MirrorOp *op, int ret) 189 { 190 MirrorBlockJob *s = op->s; 191 struct iovec *iov; 192 int64_t chunk_num; 193 int i, nb_chunks; 194 195 trace_mirror_iteration_done(s, op->offset, op->bytes, ret); 196 197 s->in_flight--; 198 s->bytes_in_flight -= op->bytes; 199 iov = op->qiov.iov; 200 for (i = 0; i < op->qiov.niov; i++) { 201 MirrorBuffer *buf = (MirrorBuffer *) iov[i].iov_base; 202 QSIMPLEQ_INSERT_TAIL(&s->buf_free, buf, next); 203 s->buf_free_count++; 204 } 205 206 chunk_num = op->offset / s->granularity; 207 nb_chunks = DIV_ROUND_UP(op->bytes, s->granularity); 208 209 bitmap_clear(s->in_flight_bitmap, chunk_num, nb_chunks); 210 QTAILQ_REMOVE(&s->ops_in_flight, op, next); 211 if (ret >= 0) { 212 if (s->cow_bitmap) { 213 bitmap_set(s->cow_bitmap, chunk_num, nb_chunks); 214 } 215 if (!s->initial_zeroing_ongoing) { 216 job_progress_update(&s->common.job, op->bytes); 217 } 218 } 219 qemu_iovec_destroy(&op->qiov); 220 221 qemu_co_queue_restart_all(&op->waiting_requests); 222 g_free(op); 223 } 224 225 static void coroutine_fn mirror_write_complete(MirrorOp *op, int ret) 226 { 227 MirrorBlockJob *s = op->s; 228 229 if (ret < 0) { 230 BlockErrorAction action; 231 232 bdrv_set_dirty_bitmap(s->dirty_bitmap, op->offset, op->bytes); 233 action = mirror_error_action(s, false, -ret); 234 if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) { 235 s->ret = ret; 236 } 237 } 238 239 mirror_iteration_done(op, ret); 240 } 241 242 static void coroutine_fn mirror_read_complete(MirrorOp *op, int ret) 243 { 244 MirrorBlockJob *s = op->s; 245 246 if (ret < 0) { 247 BlockErrorAction action; 248 249 bdrv_set_dirty_bitmap(s->dirty_bitmap, op->offset, op->bytes); 250 action = mirror_error_action(s, true, -ret); 251 if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) { 252 s->ret = ret; 253 } 254 255 mirror_iteration_done(op, ret); 256 return; 257 } 258 259 ret = blk_co_pwritev(s->target, op->offset, op->qiov.size, &op->qiov, 0); 260 mirror_write_complete(op, ret); 261 } 262 263 /* Clip bytes relative to offset to not exceed end-of-file */ 264 static inline int64_t mirror_clip_bytes(MirrorBlockJob *s, 265 int64_t offset, 266 int64_t bytes) 267 { 268 return MIN(bytes, s->bdev_length - offset); 269 } 270 271 /* Round offset and/or bytes to target cluster if COW is needed, and 272 * return the offset of the adjusted tail against original. */ 273 static int coroutine_fn mirror_cow_align(MirrorBlockJob *s, int64_t *offset, 274 uint64_t *bytes) 275 { 276 bool need_cow; 277 int ret = 0; 278 int64_t align_offset = *offset; 279 int64_t align_bytes = *bytes; 280 int max_bytes = s->granularity * s->max_iov; 281 282 need_cow = !test_bit(*offset / s->granularity, s->cow_bitmap); 283 need_cow |= !test_bit((*offset + *bytes - 1) / s->granularity, 284 s->cow_bitmap); 285 if (need_cow) { 286 bdrv_round_to_clusters(blk_bs(s->target), *offset, *bytes, 287 &align_offset, &align_bytes); 288 } 289 290 if (align_bytes > max_bytes) { 291 align_bytes = max_bytes; 292 if (need_cow) { 293 align_bytes = QEMU_ALIGN_DOWN(align_bytes, s->target_cluster_size); 294 } 295 } 296 /* Clipping may result in align_bytes unaligned to chunk boundary, but 297 * that doesn't matter because it's already the end of source image. */ 298 align_bytes = mirror_clip_bytes(s, align_offset, align_bytes); 299 300 ret = align_offset + align_bytes - (*offset + *bytes); 301 *offset = align_offset; 302 *bytes = align_bytes; 303 assert(ret >= 0); 304 return ret; 305 } 306 307 static inline void coroutine_fn 308 mirror_wait_for_free_in_flight_slot(MirrorBlockJob *s) 309 { 310 MirrorOp *op; 311 312 QTAILQ_FOREACH(op, &s->ops_in_flight, next) { 313 /* 314 * Do not wait on pseudo ops, because it may in turn wait on 315 * some other operation to start, which may in fact be the 316 * caller of this function. Since there is only one pseudo op 317 * at any given time, we will always find some real operation 318 * to wait on. 319 * Also, do not wait on active operations, because they do not 320 * use up in-flight slots. 321 */ 322 if (!op->is_pseudo_op && op->is_in_flight && !op->is_active_write) { 323 qemu_co_queue_wait(&op->waiting_requests, NULL); 324 return; 325 } 326 } 327 abort(); 328 } 329 330 /* Perform a mirror copy operation. 331 * 332 * *op->bytes_handled is set to the number of bytes copied after and 333 * including offset, excluding any bytes copied prior to offset due 334 * to alignment. This will be op->bytes if no alignment is necessary, 335 * or (new_end - op->offset) if the tail is rounded up or down due to 336 * alignment or buffer limit. 337 */ 338 static void coroutine_fn mirror_co_read(void *opaque) 339 { 340 MirrorOp *op = opaque; 341 MirrorBlockJob *s = op->s; 342 int nb_chunks; 343 uint64_t ret; 344 uint64_t max_bytes; 345 346 max_bytes = s->granularity * s->max_iov; 347 348 /* We can only handle as much as buf_size at a time. */ 349 op->bytes = MIN(s->buf_size, MIN(max_bytes, op->bytes)); 350 assert(op->bytes); 351 assert(op->bytes < BDRV_REQUEST_MAX_BYTES); 352 *op->bytes_handled = op->bytes; 353 354 if (s->cow_bitmap) { 355 *op->bytes_handled += mirror_cow_align(s, &op->offset, &op->bytes); 356 } 357 /* Cannot exceed BDRV_REQUEST_MAX_BYTES + INT_MAX */ 358 assert(*op->bytes_handled <= UINT_MAX); 359 assert(op->bytes <= s->buf_size); 360 /* The offset is granularity-aligned because: 361 * 1) Caller passes in aligned values; 362 * 2) mirror_cow_align is used only when target cluster is larger. */ 363 assert(QEMU_IS_ALIGNED(op->offset, s->granularity)); 364 /* The range is sector-aligned, since bdrv_getlength() rounds up. */ 365 assert(QEMU_IS_ALIGNED(op->bytes, BDRV_SECTOR_SIZE)); 366 nb_chunks = DIV_ROUND_UP(op->bytes, s->granularity); 367 368 while (s->buf_free_count < nb_chunks) { 369 trace_mirror_yield_in_flight(s, op->offset, s->in_flight); 370 mirror_wait_for_free_in_flight_slot(s); 371 } 372 373 /* Now make a QEMUIOVector taking enough granularity-sized chunks 374 * from s->buf_free. 375 */ 376 qemu_iovec_init(&op->qiov, nb_chunks); 377 while (nb_chunks-- > 0) { 378 MirrorBuffer *buf = QSIMPLEQ_FIRST(&s->buf_free); 379 size_t remaining = op->bytes - op->qiov.size; 380 381 QSIMPLEQ_REMOVE_HEAD(&s->buf_free, next); 382 s->buf_free_count--; 383 qemu_iovec_add(&op->qiov, buf, MIN(s->granularity, remaining)); 384 } 385 386 /* Copy the dirty cluster. */ 387 s->in_flight++; 388 s->bytes_in_flight += op->bytes; 389 op->is_in_flight = true; 390 trace_mirror_one_iteration(s, op->offset, op->bytes); 391 392 WITH_GRAPH_RDLOCK_GUARD() { 393 ret = bdrv_co_preadv(s->mirror_top_bs->backing, op->offset, op->bytes, 394 &op->qiov, 0); 395 } 396 mirror_read_complete(op, ret); 397 } 398 399 static void coroutine_fn mirror_co_zero(void *opaque) 400 { 401 MirrorOp *op = opaque; 402 int ret; 403 404 op->s->in_flight++; 405 op->s->bytes_in_flight += op->bytes; 406 *op->bytes_handled = op->bytes; 407 op->is_in_flight = true; 408 409 ret = blk_co_pwrite_zeroes(op->s->target, op->offset, op->bytes, 410 op->s->unmap ? BDRV_REQ_MAY_UNMAP : 0); 411 mirror_write_complete(op, ret); 412 } 413 414 static void coroutine_fn mirror_co_discard(void *opaque) 415 { 416 MirrorOp *op = opaque; 417 int ret; 418 419 op->s->in_flight++; 420 op->s->bytes_in_flight += op->bytes; 421 *op->bytes_handled = op->bytes; 422 op->is_in_flight = true; 423 424 ret = blk_co_pdiscard(op->s->target, op->offset, op->bytes); 425 mirror_write_complete(op, ret); 426 } 427 428 static unsigned mirror_perform(MirrorBlockJob *s, int64_t offset, 429 unsigned bytes, MirrorMethod mirror_method) 430 { 431 MirrorOp *op; 432 Coroutine *co; 433 int64_t bytes_handled = -1; 434 435 op = g_new(MirrorOp, 1); 436 *op = (MirrorOp){ 437 .s = s, 438 .offset = offset, 439 .bytes = bytes, 440 .bytes_handled = &bytes_handled, 441 }; 442 qemu_co_queue_init(&op->waiting_requests); 443 444 switch (mirror_method) { 445 case MIRROR_METHOD_COPY: 446 co = qemu_coroutine_create(mirror_co_read, op); 447 break; 448 case MIRROR_METHOD_ZERO: 449 co = qemu_coroutine_create(mirror_co_zero, op); 450 break; 451 case MIRROR_METHOD_DISCARD: 452 co = qemu_coroutine_create(mirror_co_discard, op); 453 break; 454 default: 455 abort(); 456 } 457 op->co = co; 458 459 QTAILQ_INSERT_TAIL(&s->ops_in_flight, op, next); 460 qemu_coroutine_enter(co); 461 /* At this point, ownership of op has been moved to the coroutine 462 * and the object may already be freed */ 463 464 /* Assert that this value has been set */ 465 assert(bytes_handled >= 0); 466 467 /* Same assertion as in mirror_co_read() (and for mirror_co_read() 468 * and mirror_co_discard(), bytes_handled == op->bytes, which 469 * is the @bytes parameter given to this function) */ 470 assert(bytes_handled <= UINT_MAX); 471 return bytes_handled; 472 } 473 474 static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) 475 { 476 BlockDriverState *source = s->mirror_top_bs->backing->bs; 477 MirrorOp *pseudo_op; 478 int64_t offset; 479 uint64_t delay_ns = 0, ret = 0; 480 /* At least the first dirty chunk is mirrored in one iteration. */ 481 int nb_chunks = 1; 482 bool write_zeroes_ok = bdrv_can_write_zeroes_with_unmap(blk_bs(s->target)); 483 int max_io_bytes = MAX(s->buf_size / MAX_IN_FLIGHT, MAX_IO_BYTES); 484 485 bdrv_dirty_bitmap_lock(s->dirty_bitmap); 486 offset = bdrv_dirty_iter_next(s->dbi); 487 if (offset < 0) { 488 bdrv_set_dirty_iter(s->dbi, 0); 489 offset = bdrv_dirty_iter_next(s->dbi); 490 trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap)); 491 assert(offset >= 0); 492 } 493 bdrv_dirty_bitmap_unlock(s->dirty_bitmap); 494 495 /* 496 * Wait for concurrent requests to @offset. The next loop will limit the 497 * copied area based on in_flight_bitmap so we only copy an area that does 498 * not overlap with concurrent in-flight requests. Still, we would like to 499 * copy something, so wait until there are at least no more requests to the 500 * very beginning of the area. 501 */ 502 mirror_wait_on_conflicts(NULL, s, offset, 1); 503 504 job_pause_point(&s->common.job); 505 506 /* Find the number of consective dirty chunks following the first dirty 507 * one, and wait for in flight requests in them. */ 508 bdrv_dirty_bitmap_lock(s->dirty_bitmap); 509 while (nb_chunks * s->granularity < s->buf_size) { 510 int64_t next_dirty; 511 int64_t next_offset = offset + nb_chunks * s->granularity; 512 int64_t next_chunk = next_offset / s->granularity; 513 if (next_offset >= s->bdev_length || 514 !bdrv_dirty_bitmap_get_locked(s->dirty_bitmap, next_offset)) { 515 break; 516 } 517 if (test_bit(next_chunk, s->in_flight_bitmap)) { 518 break; 519 } 520 521 next_dirty = bdrv_dirty_iter_next(s->dbi); 522 if (next_dirty > next_offset || next_dirty < 0) { 523 /* The bitmap iterator's cache is stale, refresh it */ 524 bdrv_set_dirty_iter(s->dbi, next_offset); 525 next_dirty = bdrv_dirty_iter_next(s->dbi); 526 } 527 assert(next_dirty == next_offset); 528 nb_chunks++; 529 } 530 531 /* Clear dirty bits before querying the block status, because 532 * calling bdrv_block_status_above could yield - if some blocks are 533 * marked dirty in this window, we need to know. 534 */ 535 bdrv_reset_dirty_bitmap_locked(s->dirty_bitmap, offset, 536 nb_chunks * s->granularity); 537 bdrv_dirty_bitmap_unlock(s->dirty_bitmap); 538 539 /* Before claiming an area in the in-flight bitmap, we have to 540 * create a MirrorOp for it so that conflicting requests can wait 541 * for it. mirror_perform() will create the real MirrorOps later, 542 * for now we just create a pseudo operation that will wake up all 543 * conflicting requests once all real operations have been 544 * launched. */ 545 pseudo_op = g_new(MirrorOp, 1); 546 *pseudo_op = (MirrorOp){ 547 .offset = offset, 548 .bytes = nb_chunks * s->granularity, 549 .is_pseudo_op = true, 550 }; 551 qemu_co_queue_init(&pseudo_op->waiting_requests); 552 QTAILQ_INSERT_TAIL(&s->ops_in_flight, pseudo_op, next); 553 554 bitmap_set(s->in_flight_bitmap, offset / s->granularity, nb_chunks); 555 while (nb_chunks > 0 && offset < s->bdev_length) { 556 int ret; 557 int64_t io_bytes; 558 int64_t io_bytes_acct; 559 MirrorMethod mirror_method = MIRROR_METHOD_COPY; 560 561 assert(!(offset % s->granularity)); 562 WITH_GRAPH_RDLOCK_GUARD() { 563 ret = bdrv_block_status_above(source, NULL, offset, 564 nb_chunks * s->granularity, 565 &io_bytes, NULL, NULL); 566 } 567 if (ret < 0) { 568 io_bytes = MIN(nb_chunks * s->granularity, max_io_bytes); 569 } else if (ret & BDRV_BLOCK_DATA) { 570 io_bytes = MIN(io_bytes, max_io_bytes); 571 } 572 573 io_bytes -= io_bytes % s->granularity; 574 if (io_bytes < s->granularity) { 575 io_bytes = s->granularity; 576 } else if (ret >= 0 && !(ret & BDRV_BLOCK_DATA)) { 577 int64_t target_offset; 578 int64_t target_bytes; 579 WITH_GRAPH_RDLOCK_GUARD() { 580 bdrv_round_to_clusters(blk_bs(s->target), offset, io_bytes, 581 &target_offset, &target_bytes); 582 } 583 if (target_offset == offset && 584 target_bytes == io_bytes) { 585 mirror_method = ret & BDRV_BLOCK_ZERO ? 586 MIRROR_METHOD_ZERO : 587 MIRROR_METHOD_DISCARD; 588 } 589 } 590 591 while (s->in_flight >= MAX_IN_FLIGHT) { 592 trace_mirror_yield_in_flight(s, offset, s->in_flight); 593 mirror_wait_for_free_in_flight_slot(s); 594 } 595 596 if (s->ret < 0) { 597 ret = 0; 598 goto fail; 599 } 600 601 io_bytes = mirror_clip_bytes(s, offset, io_bytes); 602 io_bytes = mirror_perform(s, offset, io_bytes, mirror_method); 603 if (mirror_method != MIRROR_METHOD_COPY && write_zeroes_ok) { 604 io_bytes_acct = 0; 605 } else { 606 io_bytes_acct = io_bytes; 607 } 608 assert(io_bytes); 609 offset += io_bytes; 610 nb_chunks -= DIV_ROUND_UP(io_bytes, s->granularity); 611 delay_ns = block_job_ratelimit_get_delay(&s->common, io_bytes_acct); 612 } 613 614 ret = delay_ns; 615 fail: 616 QTAILQ_REMOVE(&s->ops_in_flight, pseudo_op, next); 617 qemu_co_queue_restart_all(&pseudo_op->waiting_requests); 618 g_free(pseudo_op); 619 620 return ret; 621 } 622 623 static void mirror_free_init(MirrorBlockJob *s) 624 { 625 int granularity = s->granularity; 626 size_t buf_size = s->buf_size; 627 uint8_t *buf = s->buf; 628 629 assert(s->buf_free_count == 0); 630 QSIMPLEQ_INIT(&s->buf_free); 631 while (buf_size != 0) { 632 MirrorBuffer *cur = (MirrorBuffer *)buf; 633 QSIMPLEQ_INSERT_TAIL(&s->buf_free, cur, next); 634 s->buf_free_count++; 635 buf_size -= granularity; 636 buf += granularity; 637 } 638 } 639 640 /* This is also used for the .pause callback. There is no matching 641 * mirror_resume() because mirror_run() will begin iterating again 642 * when the job is resumed. 643 */ 644 static void coroutine_fn mirror_wait_for_all_io(MirrorBlockJob *s) 645 { 646 while (s->in_flight > 0) { 647 mirror_wait_for_free_in_flight_slot(s); 648 } 649 } 650 651 /** 652 * mirror_exit_common: handle both abort() and prepare() cases. 653 * for .prepare, returns 0 on success and -errno on failure. 654 * for .abort cases, denoted by abort = true, MUST return 0. 655 */ 656 static int mirror_exit_common(Job *job) 657 { 658 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job); 659 BlockJob *bjob = &s->common; 660 MirrorBDSOpaque *bs_opaque; 661 AioContext *replace_aio_context = NULL; 662 BlockDriverState *src; 663 BlockDriverState *target_bs; 664 BlockDriverState *mirror_top_bs; 665 Error *local_err = NULL; 666 bool abort = job->ret < 0; 667 int ret = 0; 668 669 if (s->prepared) { 670 return 0; 671 } 672 s->prepared = true; 673 674 mirror_top_bs = s->mirror_top_bs; 675 bs_opaque = mirror_top_bs->opaque; 676 src = mirror_top_bs->backing->bs; 677 target_bs = blk_bs(s->target); 678 679 if (bdrv_chain_contains(src, target_bs)) { 680 bdrv_unfreeze_backing_chain(mirror_top_bs, target_bs); 681 } 682 683 bdrv_release_dirty_bitmap(s->dirty_bitmap); 684 685 /* Make sure that the source BDS doesn't go away during bdrv_replace_node, 686 * before we can call bdrv_drained_end */ 687 bdrv_ref(src); 688 bdrv_ref(mirror_top_bs); 689 bdrv_ref(target_bs); 690 691 /* 692 * Remove target parent that still uses BLK_PERM_WRITE/RESIZE before 693 * inserting target_bs at s->to_replace, where we might not be able to get 694 * these permissions. 695 */ 696 blk_unref(s->target); 697 s->target = NULL; 698 699 /* We don't access the source any more. Dropping any WRITE/RESIZE is 700 * required before it could become a backing file of target_bs. Not having 701 * these permissions any more means that we can't allow any new requests on 702 * mirror_top_bs from now on, so keep it drained. */ 703 bdrv_drained_begin(mirror_top_bs); 704 bs_opaque->stop = true; 705 bdrv_child_refresh_perms(mirror_top_bs, mirror_top_bs->backing, 706 &error_abort); 707 if (!abort && s->backing_mode == MIRROR_SOURCE_BACKING_CHAIN) { 708 BlockDriverState *backing = s->is_none_mode ? src : s->base; 709 BlockDriverState *unfiltered_target = bdrv_skip_filters(target_bs); 710 711 if (bdrv_cow_bs(unfiltered_target) != backing) { 712 bdrv_set_backing_hd(unfiltered_target, backing, &local_err); 713 if (local_err) { 714 error_report_err(local_err); 715 local_err = NULL; 716 ret = -EPERM; 717 } 718 } 719 } else if (!abort && s->backing_mode == MIRROR_OPEN_BACKING_CHAIN) { 720 assert(!bdrv_backing_chain_next(target_bs)); 721 ret = bdrv_open_backing_file(bdrv_skip_filters(target_bs), NULL, 722 "backing", &local_err); 723 if (ret < 0) { 724 error_report_err(local_err); 725 local_err = NULL; 726 } 727 } 728 729 if (s->to_replace) { 730 replace_aio_context = bdrv_get_aio_context(s->to_replace); 731 aio_context_acquire(replace_aio_context); 732 } 733 734 if (s->should_complete && !abort) { 735 BlockDriverState *to_replace = s->to_replace ?: src; 736 bool ro = bdrv_is_read_only(to_replace); 737 738 if (ro != bdrv_is_read_only(target_bs)) { 739 bdrv_reopen_set_read_only(target_bs, ro, NULL); 740 } 741 742 /* The mirror job has no requests in flight any more, but we need to 743 * drain potential other users of the BDS before changing the graph. */ 744 assert(s->in_drain); 745 bdrv_drained_begin(target_bs); 746 /* 747 * Cannot use check_to_replace_node() here, because that would 748 * check for an op blocker on @to_replace, and we have our own 749 * there. 750 * 751 * TODO Pull out the writer lock from bdrv_replace_node() to here 752 */ 753 bdrv_graph_rdlock_main_loop(); 754 if (bdrv_recurse_can_replace(src, to_replace)) { 755 bdrv_replace_node(to_replace, target_bs, &local_err); 756 } else { 757 error_setg(&local_err, "Can no longer replace '%s' by '%s', " 758 "because it can no longer be guaranteed that doing so " 759 "would not lead to an abrupt change of visible data", 760 to_replace->node_name, target_bs->node_name); 761 } 762 bdrv_graph_rdunlock_main_loop(); 763 bdrv_drained_end(target_bs); 764 if (local_err) { 765 error_report_err(local_err); 766 ret = -EPERM; 767 } 768 } 769 if (s->to_replace) { 770 bdrv_op_unblock_all(s->to_replace, s->replace_blocker); 771 error_free(s->replace_blocker); 772 bdrv_unref(s->to_replace); 773 } 774 if (replace_aio_context) { 775 aio_context_release(replace_aio_context); 776 } 777 g_free(s->replaces); 778 bdrv_unref(target_bs); 779 780 /* 781 * Remove the mirror filter driver from the graph. Before this, get rid of 782 * the blockers on the intermediate nodes so that the resulting state is 783 * valid. 784 */ 785 block_job_remove_all_bdrv(bjob); 786 bdrv_replace_node(mirror_top_bs, mirror_top_bs->backing->bs, &error_abort); 787 788 bs_opaque->job = NULL; 789 790 bdrv_drained_end(src); 791 bdrv_drained_end(mirror_top_bs); 792 s->in_drain = false; 793 bdrv_unref(mirror_top_bs); 794 bdrv_unref(src); 795 796 return ret; 797 } 798 799 static int mirror_prepare(Job *job) 800 { 801 return mirror_exit_common(job); 802 } 803 804 static void mirror_abort(Job *job) 805 { 806 int ret = mirror_exit_common(job); 807 assert(ret == 0); 808 } 809 810 static void coroutine_fn mirror_throttle(MirrorBlockJob *s) 811 { 812 int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 813 814 if (now - s->last_pause_ns > BLOCK_JOB_SLICE_TIME) { 815 s->last_pause_ns = now; 816 job_sleep_ns(&s->common.job, 0); 817 } else { 818 job_pause_point(&s->common.job); 819 } 820 } 821 822 static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s) 823 { 824 int64_t offset; 825 BlockDriverState *bs = s->mirror_top_bs->backing->bs; 826 BlockDriverState *target_bs = blk_bs(s->target); 827 int ret; 828 int64_t count; 829 830 if (s->zero_target) { 831 if (!bdrv_can_write_zeroes_with_unmap(target_bs)) { 832 bdrv_set_dirty_bitmap(s->dirty_bitmap, 0, s->bdev_length); 833 return 0; 834 } 835 836 s->initial_zeroing_ongoing = true; 837 for (offset = 0; offset < s->bdev_length; ) { 838 int bytes = MIN(s->bdev_length - offset, 839 QEMU_ALIGN_DOWN(INT_MAX, s->granularity)); 840 841 mirror_throttle(s); 842 843 if (job_is_cancelled(&s->common.job)) { 844 s->initial_zeroing_ongoing = false; 845 return 0; 846 } 847 848 if (s->in_flight >= MAX_IN_FLIGHT) { 849 trace_mirror_yield(s, UINT64_MAX, s->buf_free_count, 850 s->in_flight); 851 mirror_wait_for_free_in_flight_slot(s); 852 continue; 853 } 854 855 mirror_perform(s, offset, bytes, MIRROR_METHOD_ZERO); 856 offset += bytes; 857 } 858 859 mirror_wait_for_all_io(s); 860 s->initial_zeroing_ongoing = false; 861 } 862 863 /* First part, loop on the sectors and initialize the dirty bitmap. */ 864 for (offset = 0; offset < s->bdev_length; ) { 865 /* Just to make sure we are not exceeding int limit. */ 866 int bytes = MIN(s->bdev_length - offset, 867 QEMU_ALIGN_DOWN(INT_MAX, s->granularity)); 868 869 mirror_throttle(s); 870 871 if (job_is_cancelled(&s->common.job)) { 872 return 0; 873 } 874 875 WITH_GRAPH_RDLOCK_GUARD() { 876 ret = bdrv_is_allocated_above(bs, s->base_overlay, true, offset, 877 bytes, &count); 878 } 879 if (ret < 0) { 880 return ret; 881 } 882 883 assert(count); 884 if (ret > 0) { 885 bdrv_set_dirty_bitmap(s->dirty_bitmap, offset, count); 886 } 887 offset += count; 888 } 889 return 0; 890 } 891 892 /* Called when going out of the streaming phase to flush the bulk of the 893 * data to the medium, or just before completing. 894 */ 895 static int coroutine_fn mirror_flush(MirrorBlockJob *s) 896 { 897 int ret = blk_co_flush(s->target); 898 if (ret < 0) { 899 if (mirror_error_action(s, false, -ret) == BLOCK_ERROR_ACTION_REPORT) { 900 s->ret = ret; 901 } 902 } 903 return ret; 904 } 905 906 static int coroutine_fn mirror_run(Job *job, Error **errp) 907 { 908 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job); 909 BlockDriverState *bs = s->mirror_top_bs->backing->bs; 910 MirrorBDSOpaque *mirror_top_opaque = s->mirror_top_bs->opaque; 911 BlockDriverState *target_bs = blk_bs(s->target); 912 bool need_drain = true; 913 BlockDeviceIoStatus iostatus; 914 int64_t length; 915 int64_t target_length; 916 BlockDriverInfo bdi; 917 char backing_filename[2]; /* we only need 2 characters because we are only 918 checking for a NULL string */ 919 int ret = 0; 920 921 if (job_is_cancelled(&s->common.job)) { 922 goto immediate_exit; 923 } 924 925 bdrv_graph_co_rdlock(); 926 s->bdev_length = bdrv_co_getlength(bs); 927 bdrv_graph_co_rdunlock(); 928 929 if (s->bdev_length < 0) { 930 ret = s->bdev_length; 931 goto immediate_exit; 932 } 933 934 target_length = blk_co_getlength(s->target); 935 if (target_length < 0) { 936 ret = target_length; 937 goto immediate_exit; 938 } 939 940 /* Active commit must resize the base image if its size differs from the 941 * active layer. */ 942 if (s->base == blk_bs(s->target)) { 943 if (s->bdev_length > target_length) { 944 ret = blk_co_truncate(s->target, s->bdev_length, false, 945 PREALLOC_MODE_OFF, 0, NULL); 946 if (ret < 0) { 947 goto immediate_exit; 948 } 949 } 950 } else if (s->bdev_length != target_length) { 951 error_setg(errp, "Source and target image have different sizes"); 952 ret = -EINVAL; 953 goto immediate_exit; 954 } 955 956 if (s->bdev_length == 0) { 957 /* Transition to the READY state and wait for complete. */ 958 job_transition_to_ready(&s->common.job); 959 s->actively_synced = true; 960 while (!job_cancel_requested(&s->common.job) && !s->should_complete) { 961 job_yield(&s->common.job); 962 } 963 goto immediate_exit; 964 } 965 966 length = DIV_ROUND_UP(s->bdev_length, s->granularity); 967 s->in_flight_bitmap = bitmap_new(length); 968 969 /* If we have no backing file yet in the destination, we cannot let 970 * the destination do COW. Instead, we copy sectors around the 971 * dirty data if needed. We need a bitmap to do that. 972 */ 973 bdrv_get_backing_filename(target_bs, backing_filename, 974 sizeof(backing_filename)); 975 bdrv_graph_co_rdlock(); 976 if (!bdrv_co_get_info(target_bs, &bdi) && bdi.cluster_size) { 977 s->target_cluster_size = bdi.cluster_size; 978 } else { 979 s->target_cluster_size = BDRV_SECTOR_SIZE; 980 } 981 bdrv_graph_co_rdunlock(); 982 if (backing_filename[0] && !bdrv_backing_chain_next(target_bs) && 983 s->granularity < s->target_cluster_size) { 984 s->buf_size = MAX(s->buf_size, s->target_cluster_size); 985 s->cow_bitmap = bitmap_new(length); 986 } 987 s->max_iov = MIN(bs->bl.max_iov, target_bs->bl.max_iov); 988 989 s->buf = qemu_try_blockalign(bs, s->buf_size); 990 if (s->buf == NULL) { 991 ret = -ENOMEM; 992 goto immediate_exit; 993 } 994 995 mirror_free_init(s); 996 997 s->last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 998 if (!s->is_none_mode) { 999 ret = mirror_dirty_init(s); 1000 if (ret < 0 || job_is_cancelled(&s->common.job)) { 1001 goto immediate_exit; 1002 } 1003 } 1004 1005 /* 1006 * Only now the job is fully initialised and mirror_top_bs should start 1007 * accessing it. 1008 */ 1009 mirror_top_opaque->job = s; 1010 1011 assert(!s->dbi); 1012 s->dbi = bdrv_dirty_iter_new(s->dirty_bitmap); 1013 for (;;) { 1014 uint64_t delay_ns = 0; 1015 int64_t cnt, delta; 1016 bool should_complete; 1017 1018 if (s->ret < 0) { 1019 ret = s->ret; 1020 goto immediate_exit; 1021 } 1022 1023 job_pause_point(&s->common.job); 1024 1025 if (job_is_cancelled(&s->common.job)) { 1026 ret = 0; 1027 goto immediate_exit; 1028 } 1029 1030 cnt = bdrv_get_dirty_count(s->dirty_bitmap); 1031 /* cnt is the number of dirty bytes remaining and s->bytes_in_flight is 1032 * the number of bytes currently being processed; together those are 1033 * the current remaining operation length */ 1034 job_progress_set_remaining(&s->common.job, 1035 s->bytes_in_flight + cnt + 1036 s->active_write_bytes_in_flight); 1037 1038 /* Note that even when no rate limit is applied we need to yield 1039 * periodically with no pending I/O so that bdrv_drain_all() returns. 1040 * We do so every BLKOCK_JOB_SLICE_TIME nanoseconds, or when there is 1041 * an error, or when the source is clean, whichever comes first. */ 1042 delta = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - s->last_pause_ns; 1043 WITH_JOB_LOCK_GUARD() { 1044 iostatus = s->common.iostatus; 1045 } 1046 if (delta < BLOCK_JOB_SLICE_TIME && 1047 iostatus == BLOCK_DEVICE_IO_STATUS_OK) { 1048 if (s->in_flight >= MAX_IN_FLIGHT || s->buf_free_count == 0 || 1049 (cnt == 0 && s->in_flight > 0)) { 1050 trace_mirror_yield(s, cnt, s->buf_free_count, s->in_flight); 1051 mirror_wait_for_free_in_flight_slot(s); 1052 continue; 1053 } else if (cnt != 0) { 1054 delay_ns = mirror_iteration(s); 1055 } 1056 } 1057 1058 should_complete = false; 1059 if (s->in_flight == 0 && cnt == 0) { 1060 trace_mirror_before_flush(s); 1061 if (!job_is_ready(&s->common.job)) { 1062 if (mirror_flush(s) < 0) { 1063 /* Go check s->ret. */ 1064 continue; 1065 } 1066 /* We're out of the streaming phase. From now on, if the job 1067 * is cancelled we will actually complete all pending I/O and 1068 * report completion. This way, block-job-cancel will leave 1069 * the target in a consistent state. 1070 */ 1071 job_transition_to_ready(&s->common.job); 1072 if (s->copy_mode != MIRROR_COPY_MODE_BACKGROUND) { 1073 s->actively_synced = true; 1074 } 1075 } 1076 1077 should_complete = s->should_complete || 1078 job_cancel_requested(&s->common.job); 1079 cnt = bdrv_get_dirty_count(s->dirty_bitmap); 1080 } 1081 1082 if (cnt == 0 && should_complete) { 1083 /* The dirty bitmap is not updated while operations are pending. 1084 * If we're about to exit, wait for pending operations before 1085 * calling bdrv_get_dirty_count(bs), or we may exit while the 1086 * source has dirty data to copy! 1087 * 1088 * Note that I/O can be submitted by the guest while 1089 * mirror_populate runs, so pause it now. Before deciding 1090 * whether to switch to target check one last time if I/O has 1091 * come in the meanwhile, and if not flush the data to disk. 1092 */ 1093 trace_mirror_before_drain(s, cnt); 1094 1095 s->in_drain = true; 1096 bdrv_drained_begin(bs); 1097 1098 /* Must be zero because we are drained */ 1099 assert(s->in_active_write_counter == 0); 1100 1101 cnt = bdrv_get_dirty_count(s->dirty_bitmap); 1102 if (cnt > 0 || mirror_flush(s) < 0) { 1103 bdrv_drained_end(bs); 1104 s->in_drain = false; 1105 continue; 1106 } 1107 1108 /* The two disks are in sync. Exit and report successful 1109 * completion. 1110 */ 1111 assert(QLIST_EMPTY(&bs->tracked_requests)); 1112 need_drain = false; 1113 break; 1114 } 1115 1116 if (job_is_ready(&s->common.job) && !should_complete) { 1117 delay_ns = (s->in_flight == 0 && 1118 cnt == 0 ? BLOCK_JOB_SLICE_TIME : 0); 1119 } 1120 trace_mirror_before_sleep(s, cnt, job_is_ready(&s->common.job), 1121 delay_ns); 1122 job_sleep_ns(&s->common.job, delay_ns); 1123 s->last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); 1124 } 1125 1126 immediate_exit: 1127 if (s->in_flight > 0) { 1128 /* We get here only if something went wrong. Either the job failed, 1129 * or it was cancelled prematurely so that we do not guarantee that 1130 * the target is a copy of the source. 1131 */ 1132 assert(ret < 0 || job_is_cancelled(&s->common.job)); 1133 assert(need_drain); 1134 mirror_wait_for_all_io(s); 1135 } 1136 1137 assert(s->in_flight == 0); 1138 qemu_vfree(s->buf); 1139 g_free(s->cow_bitmap); 1140 g_free(s->in_flight_bitmap); 1141 bdrv_dirty_iter_free(s->dbi); 1142 1143 if (need_drain) { 1144 s->in_drain = true; 1145 bdrv_drained_begin(bs); 1146 } 1147 1148 return ret; 1149 } 1150 1151 static void mirror_complete(Job *job, Error **errp) 1152 { 1153 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job); 1154 1155 if (!job_is_ready(job)) { 1156 error_setg(errp, "The active block job '%s' cannot be completed", 1157 job->id); 1158 return; 1159 } 1160 1161 /* block all operations on to_replace bs */ 1162 if (s->replaces) { 1163 AioContext *replace_aio_context; 1164 1165 s->to_replace = bdrv_find_node(s->replaces); 1166 if (!s->to_replace) { 1167 error_setg(errp, "Node name '%s' not found", s->replaces); 1168 return; 1169 } 1170 1171 replace_aio_context = bdrv_get_aio_context(s->to_replace); 1172 aio_context_acquire(replace_aio_context); 1173 1174 /* TODO Translate this into child freeze system. */ 1175 error_setg(&s->replace_blocker, 1176 "block device is in use by block-job-complete"); 1177 bdrv_op_block_all(s->to_replace, s->replace_blocker); 1178 bdrv_ref(s->to_replace); 1179 1180 aio_context_release(replace_aio_context); 1181 } 1182 1183 s->should_complete = true; 1184 1185 /* If the job is paused, it will be re-entered when it is resumed */ 1186 WITH_JOB_LOCK_GUARD() { 1187 if (!job->paused) { 1188 job_enter_cond_locked(job, NULL); 1189 } 1190 } 1191 } 1192 1193 static void coroutine_fn mirror_pause(Job *job) 1194 { 1195 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job); 1196 1197 mirror_wait_for_all_io(s); 1198 } 1199 1200 static bool mirror_drained_poll(BlockJob *job) 1201 { 1202 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); 1203 1204 /* If the job isn't paused nor cancelled, we can't be sure that it won't 1205 * issue more requests. We make an exception if we've reached this point 1206 * from one of our own drain sections, to avoid a deadlock waiting for 1207 * ourselves. 1208 */ 1209 WITH_JOB_LOCK_GUARD() { 1210 if (!s->common.job.paused && !job_is_cancelled_locked(&job->job) 1211 && !s->in_drain) { 1212 return true; 1213 } 1214 } 1215 1216 return !!s->in_flight; 1217 } 1218 1219 static bool mirror_cancel(Job *job, bool force) 1220 { 1221 MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job); 1222 BlockDriverState *target = blk_bs(s->target); 1223 1224 /* 1225 * Before the job is READY, we treat any cancellation like a 1226 * force-cancellation. 1227 */ 1228 force = force || !job_is_ready(job); 1229 1230 if (force) { 1231 bdrv_cancel_in_flight(target); 1232 } 1233 return force; 1234 } 1235 1236 static bool commit_active_cancel(Job *job, bool force) 1237 { 1238 /* Same as above in mirror_cancel() */ 1239 return force || !job_is_ready(job); 1240 } 1241 1242 static const BlockJobDriver mirror_job_driver = { 1243 .job_driver = { 1244 .instance_size = sizeof(MirrorBlockJob), 1245 .job_type = JOB_TYPE_MIRROR, 1246 .free = block_job_free, 1247 .user_resume = block_job_user_resume, 1248 .run = mirror_run, 1249 .prepare = mirror_prepare, 1250 .abort = mirror_abort, 1251 .pause = mirror_pause, 1252 .complete = mirror_complete, 1253 .cancel = mirror_cancel, 1254 }, 1255 .drained_poll = mirror_drained_poll, 1256 }; 1257 1258 static const BlockJobDriver commit_active_job_driver = { 1259 .job_driver = { 1260 .instance_size = sizeof(MirrorBlockJob), 1261 .job_type = JOB_TYPE_COMMIT, 1262 .free = block_job_free, 1263 .user_resume = block_job_user_resume, 1264 .run = mirror_run, 1265 .prepare = mirror_prepare, 1266 .abort = mirror_abort, 1267 .pause = mirror_pause, 1268 .complete = mirror_complete, 1269 .cancel = commit_active_cancel, 1270 }, 1271 .drained_poll = mirror_drained_poll, 1272 }; 1273 1274 static void coroutine_fn 1275 do_sync_target_write(MirrorBlockJob *job, MirrorMethod method, 1276 uint64_t offset, uint64_t bytes, 1277 QEMUIOVector *qiov, int flags) 1278 { 1279 int ret; 1280 size_t qiov_offset = 0; 1281 int64_t bitmap_offset, bitmap_end; 1282 1283 if (!QEMU_IS_ALIGNED(offset, job->granularity) && 1284 bdrv_dirty_bitmap_get(job->dirty_bitmap, offset)) 1285 { 1286 /* 1287 * Dirty unaligned padding: ignore it. 1288 * 1289 * Reasoning: 1290 * 1. If we copy it, we can't reset corresponding bit in 1291 * dirty_bitmap as there may be some "dirty" bytes still not 1292 * copied. 1293 * 2. It's already dirty, so skipping it we don't diverge mirror 1294 * progress. 1295 * 1296 * Note, that because of this, guest write may have no contribution 1297 * into mirror converge, but that's not bad, as we have background 1298 * process of mirroring. If under some bad circumstances (high guest 1299 * IO load) background process starve, we will not converge anyway, 1300 * even if each write will contribute, as guest is not guaranteed to 1301 * rewrite the whole disk. 1302 */ 1303 qiov_offset = QEMU_ALIGN_UP(offset, job->granularity) - offset; 1304 if (bytes <= qiov_offset) { 1305 /* nothing to do after shrink */ 1306 return; 1307 } 1308 offset += qiov_offset; 1309 bytes -= qiov_offset; 1310 } 1311 1312 if (!QEMU_IS_ALIGNED(offset + bytes, job->granularity) && 1313 bdrv_dirty_bitmap_get(job->dirty_bitmap, offset + bytes - 1)) 1314 { 1315 uint64_t tail = (offset + bytes) % job->granularity; 1316 1317 if (bytes <= tail) { 1318 /* nothing to do after shrink */ 1319 return; 1320 } 1321 bytes -= tail; 1322 } 1323 1324 /* 1325 * Tails are either clean or shrunk, so for bitmap resetting 1326 * we safely align the range down. 1327 */ 1328 bitmap_offset = QEMU_ALIGN_UP(offset, job->granularity); 1329 bitmap_end = QEMU_ALIGN_DOWN(offset + bytes, job->granularity); 1330 if (bitmap_offset < bitmap_end) { 1331 bdrv_reset_dirty_bitmap(job->dirty_bitmap, bitmap_offset, 1332 bitmap_end - bitmap_offset); 1333 } 1334 1335 job_progress_increase_remaining(&job->common.job, bytes); 1336 job->active_write_bytes_in_flight += bytes; 1337 1338 switch (method) { 1339 case MIRROR_METHOD_COPY: 1340 ret = blk_co_pwritev_part(job->target, offset, bytes, 1341 qiov, qiov_offset, flags); 1342 break; 1343 1344 case MIRROR_METHOD_ZERO: 1345 assert(!qiov); 1346 ret = blk_co_pwrite_zeroes(job->target, offset, bytes, flags); 1347 break; 1348 1349 case MIRROR_METHOD_DISCARD: 1350 assert(!qiov); 1351 ret = blk_co_pdiscard(job->target, offset, bytes); 1352 break; 1353 1354 default: 1355 abort(); 1356 } 1357 1358 job->active_write_bytes_in_flight -= bytes; 1359 if (ret >= 0) { 1360 job_progress_update(&job->common.job, bytes); 1361 } else { 1362 BlockErrorAction action; 1363 1364 /* 1365 * We failed, so we should mark dirty the whole area, aligned up. 1366 * Note that we don't care about shrunk tails if any: they were dirty 1367 * at function start, and they must be still dirty, as we've locked 1368 * the region for in-flight op. 1369 */ 1370 bitmap_offset = QEMU_ALIGN_DOWN(offset, job->granularity); 1371 bitmap_end = QEMU_ALIGN_UP(offset + bytes, job->granularity); 1372 bdrv_set_dirty_bitmap(job->dirty_bitmap, bitmap_offset, 1373 bitmap_end - bitmap_offset); 1374 job->actively_synced = false; 1375 1376 action = mirror_error_action(job, false, -ret); 1377 if (action == BLOCK_ERROR_ACTION_REPORT) { 1378 if (!job->ret) { 1379 job->ret = ret; 1380 } 1381 } 1382 } 1383 } 1384 1385 static MirrorOp *coroutine_fn active_write_prepare(MirrorBlockJob *s, 1386 uint64_t offset, 1387 uint64_t bytes) 1388 { 1389 MirrorOp *op; 1390 uint64_t start_chunk = offset / s->granularity; 1391 uint64_t end_chunk = DIV_ROUND_UP(offset + bytes, s->granularity); 1392 1393 op = g_new(MirrorOp, 1); 1394 *op = (MirrorOp){ 1395 .s = s, 1396 .offset = offset, 1397 .bytes = bytes, 1398 .is_active_write = true, 1399 .is_in_flight = true, 1400 .co = qemu_coroutine_self(), 1401 }; 1402 qemu_co_queue_init(&op->waiting_requests); 1403 QTAILQ_INSERT_TAIL(&s->ops_in_flight, op, next); 1404 1405 s->in_active_write_counter++; 1406 1407 /* 1408 * Wait for concurrent requests affecting the area. If there are already 1409 * running requests that are copying off now-to-be stale data in the area, 1410 * we must wait for them to finish before we begin writing fresh data to the 1411 * target so that the write operations appear in the correct order. 1412 * Note that background requests (see mirror_iteration()) in contrast only 1413 * wait for conflicting requests at the start of the dirty area, and then 1414 * (based on the in_flight_bitmap) truncate the area to copy so it will not 1415 * conflict with any requests beyond that. For active writes, however, we 1416 * cannot truncate that area. The request from our parent must be blocked 1417 * until the area is copied in full. Therefore, we must wait for the whole 1418 * area to become free of concurrent requests. 1419 */ 1420 mirror_wait_on_conflicts(op, s, offset, bytes); 1421 1422 bitmap_set(s->in_flight_bitmap, start_chunk, end_chunk - start_chunk); 1423 1424 return op; 1425 } 1426 1427 static void coroutine_fn GRAPH_RDLOCK active_write_settle(MirrorOp *op) 1428 { 1429 uint64_t start_chunk = op->offset / op->s->granularity; 1430 uint64_t end_chunk = DIV_ROUND_UP(op->offset + op->bytes, 1431 op->s->granularity); 1432 1433 if (!--op->s->in_active_write_counter && op->s->actively_synced) { 1434 BdrvChild *source = op->s->mirror_top_bs->backing; 1435 1436 if (QLIST_FIRST(&source->bs->parents) == source && 1437 QLIST_NEXT(source, next_parent) == NULL) 1438 { 1439 /* Assert that we are back in sync once all active write 1440 * operations are settled. 1441 * Note that we can only assert this if the mirror node 1442 * is the source node's only parent. */ 1443 assert(!bdrv_get_dirty_count(op->s->dirty_bitmap)); 1444 } 1445 } 1446 bitmap_clear(op->s->in_flight_bitmap, start_chunk, end_chunk - start_chunk); 1447 QTAILQ_REMOVE(&op->s->ops_in_flight, op, next); 1448 qemu_co_queue_restart_all(&op->waiting_requests); 1449 g_free(op); 1450 } 1451 1452 static int coroutine_fn GRAPH_RDLOCK 1453 bdrv_mirror_top_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes, 1454 QEMUIOVector *qiov, BdrvRequestFlags flags) 1455 { 1456 return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags); 1457 } 1458 1459 static int coroutine_fn GRAPH_RDLOCK 1460 bdrv_mirror_top_do_write(BlockDriverState *bs, MirrorMethod method, 1461 uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, 1462 int flags) 1463 { 1464 MirrorOp *op = NULL; 1465 MirrorBDSOpaque *s = bs->opaque; 1466 int ret = 0; 1467 bool copy_to_target = false; 1468 1469 if (s->job) { 1470 copy_to_target = s->job->ret >= 0 && 1471 !job_is_cancelled(&s->job->common.job) && 1472 s->job->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING; 1473 } 1474 1475 if (copy_to_target) { 1476 op = active_write_prepare(s->job, offset, bytes); 1477 } 1478 1479 switch (method) { 1480 case MIRROR_METHOD_COPY: 1481 ret = bdrv_co_pwritev(bs->backing, offset, bytes, qiov, flags); 1482 break; 1483 1484 case MIRROR_METHOD_ZERO: 1485 ret = bdrv_co_pwrite_zeroes(bs->backing, offset, bytes, flags); 1486 break; 1487 1488 case MIRROR_METHOD_DISCARD: 1489 ret = bdrv_co_pdiscard(bs->backing, offset, bytes); 1490 break; 1491 1492 default: 1493 abort(); 1494 } 1495 1496 if (ret < 0) { 1497 goto out; 1498 } 1499 1500 if (copy_to_target) { 1501 do_sync_target_write(s->job, method, offset, bytes, qiov, flags); 1502 } 1503 1504 out: 1505 if (copy_to_target) { 1506 active_write_settle(op); 1507 } 1508 return ret; 1509 } 1510 1511 static int coroutine_fn GRAPH_RDLOCK 1512 bdrv_mirror_top_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes, 1513 QEMUIOVector *qiov, BdrvRequestFlags flags) 1514 { 1515 MirrorBDSOpaque *s = bs->opaque; 1516 QEMUIOVector bounce_qiov; 1517 void *bounce_buf; 1518 int ret = 0; 1519 bool copy_to_target = false; 1520 1521 if (s->job) { 1522 copy_to_target = s->job->ret >= 0 && 1523 !job_is_cancelled(&s->job->common.job) && 1524 s->job->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING; 1525 } 1526 1527 if (copy_to_target) { 1528 /* The guest might concurrently modify the data to write; but 1529 * the data on source and destination must match, so we have 1530 * to use a bounce buffer if we are going to write to the 1531 * target now. */ 1532 bounce_buf = qemu_blockalign(bs, bytes); 1533 iov_to_buf_full(qiov->iov, qiov->niov, 0, bounce_buf, bytes); 1534 1535 qemu_iovec_init(&bounce_qiov, 1); 1536 qemu_iovec_add(&bounce_qiov, bounce_buf, bytes); 1537 qiov = &bounce_qiov; 1538 1539 flags &= ~BDRV_REQ_REGISTERED_BUF; 1540 } 1541 1542 ret = bdrv_mirror_top_do_write(bs, MIRROR_METHOD_COPY, offset, bytes, qiov, 1543 flags); 1544 1545 if (copy_to_target) { 1546 qemu_iovec_destroy(&bounce_qiov); 1547 qemu_vfree(bounce_buf); 1548 } 1549 1550 return ret; 1551 } 1552 1553 static int coroutine_fn GRAPH_RDLOCK bdrv_mirror_top_flush(BlockDriverState *bs) 1554 { 1555 if (bs->backing == NULL) { 1556 /* we can be here after failed bdrv_append in mirror_start_job */ 1557 return 0; 1558 } 1559 return bdrv_co_flush(bs->backing->bs); 1560 } 1561 1562 static int coroutine_fn GRAPH_RDLOCK 1563 bdrv_mirror_top_pwrite_zeroes(BlockDriverState *bs, int64_t offset, 1564 int64_t bytes, BdrvRequestFlags flags) 1565 { 1566 return bdrv_mirror_top_do_write(bs, MIRROR_METHOD_ZERO, offset, bytes, NULL, 1567 flags); 1568 } 1569 1570 static int coroutine_fn GRAPH_RDLOCK 1571 bdrv_mirror_top_pdiscard(BlockDriverState *bs, int64_t offset, int64_t bytes) 1572 { 1573 return bdrv_mirror_top_do_write(bs, MIRROR_METHOD_DISCARD, offset, bytes, 1574 NULL, 0); 1575 } 1576 1577 static void bdrv_mirror_top_refresh_filename(BlockDriverState *bs) 1578 { 1579 if (bs->backing == NULL) { 1580 /* we can be here after failed bdrv_attach_child in 1581 * bdrv_set_backing_hd */ 1582 return; 1583 } 1584 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), 1585 bs->backing->bs->filename); 1586 } 1587 1588 static void bdrv_mirror_top_child_perm(BlockDriverState *bs, BdrvChild *c, 1589 BdrvChildRole role, 1590 BlockReopenQueue *reopen_queue, 1591 uint64_t perm, uint64_t shared, 1592 uint64_t *nperm, uint64_t *nshared) 1593 { 1594 MirrorBDSOpaque *s = bs->opaque; 1595 1596 if (s->stop) { 1597 /* 1598 * If the job is to be stopped, we do not need to forward 1599 * anything to the real image. 1600 */ 1601 *nperm = 0; 1602 *nshared = BLK_PERM_ALL; 1603 return; 1604 } 1605 1606 bdrv_default_perms(bs, c, role, reopen_queue, 1607 perm, shared, nperm, nshared); 1608 1609 if (s->is_commit) { 1610 /* 1611 * For commit jobs, we cannot take CONSISTENT_READ, because 1612 * that permission is unshared for everything above the base 1613 * node (except for filters on the base node). 1614 * We also have to force-share the WRITE permission, or 1615 * otherwise we would block ourselves at the base node (if 1616 * writes are blocked for a node, they are also blocked for 1617 * its backing file). 1618 * (We could also share RESIZE, because it may be needed for 1619 * the target if its size is less than the top node's; but 1620 * bdrv_default_perms_for_cow() automatically shares RESIZE 1621 * for backing nodes if WRITE is shared, so there is no need 1622 * to do it here.) 1623 */ 1624 *nperm &= ~BLK_PERM_CONSISTENT_READ; 1625 *nshared |= BLK_PERM_WRITE; 1626 } 1627 } 1628 1629 /* Dummy node that provides consistent read to its users without requiring it 1630 * from its backing file and that allows writes on the backing file chain. */ 1631 static BlockDriver bdrv_mirror_top = { 1632 .format_name = "mirror_top", 1633 .bdrv_co_preadv = bdrv_mirror_top_preadv, 1634 .bdrv_co_pwritev = bdrv_mirror_top_pwritev, 1635 .bdrv_co_pwrite_zeroes = bdrv_mirror_top_pwrite_zeroes, 1636 .bdrv_co_pdiscard = bdrv_mirror_top_pdiscard, 1637 .bdrv_co_flush = bdrv_mirror_top_flush, 1638 .bdrv_refresh_filename = bdrv_mirror_top_refresh_filename, 1639 .bdrv_child_perm = bdrv_mirror_top_child_perm, 1640 1641 .is_filter = true, 1642 .filtered_child_is_backing = true, 1643 }; 1644 1645 static BlockJob *mirror_start_job( 1646 const char *job_id, BlockDriverState *bs, 1647 int creation_flags, BlockDriverState *target, 1648 const char *replaces, int64_t speed, 1649 uint32_t granularity, int64_t buf_size, 1650 BlockMirrorBackingMode backing_mode, 1651 bool zero_target, 1652 BlockdevOnError on_source_error, 1653 BlockdevOnError on_target_error, 1654 bool unmap, 1655 BlockCompletionFunc *cb, 1656 void *opaque, 1657 const BlockJobDriver *driver, 1658 bool is_none_mode, BlockDriverState *base, 1659 bool auto_complete, const char *filter_node_name, 1660 bool is_mirror, MirrorCopyMode copy_mode, 1661 Error **errp) 1662 { 1663 MirrorBlockJob *s; 1664 MirrorBDSOpaque *bs_opaque; 1665 BlockDriverState *mirror_top_bs; 1666 bool target_is_backing; 1667 uint64_t target_perms, target_shared_perms; 1668 int ret; 1669 1670 if (granularity == 0) { 1671 granularity = bdrv_get_default_bitmap_granularity(target); 1672 } 1673 1674 assert(is_power_of_2(granularity)); 1675 1676 if (buf_size < 0) { 1677 error_setg(errp, "Invalid parameter 'buf-size'"); 1678 return NULL; 1679 } 1680 1681 if (buf_size == 0) { 1682 buf_size = DEFAULT_MIRROR_BUF_SIZE; 1683 } 1684 1685 if (bdrv_skip_filters(bs) == bdrv_skip_filters(target)) { 1686 error_setg(errp, "Can't mirror node into itself"); 1687 return NULL; 1688 } 1689 1690 target_is_backing = bdrv_chain_contains(bs, target); 1691 1692 /* In the case of active commit, add dummy driver to provide consistent 1693 * reads on the top, while disabling it in the intermediate nodes, and make 1694 * the backing chain writable. */ 1695 mirror_top_bs = bdrv_new_open_driver(&bdrv_mirror_top, filter_node_name, 1696 BDRV_O_RDWR, errp); 1697 if (mirror_top_bs == NULL) { 1698 return NULL; 1699 } 1700 if (!filter_node_name) { 1701 mirror_top_bs->implicit = true; 1702 } 1703 1704 /* So that we can always drop this node */ 1705 mirror_top_bs->never_freeze = true; 1706 1707 mirror_top_bs->total_sectors = bs->total_sectors; 1708 mirror_top_bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED; 1709 mirror_top_bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED | 1710 BDRV_REQ_NO_FALLBACK; 1711 bs_opaque = g_new0(MirrorBDSOpaque, 1); 1712 mirror_top_bs->opaque = bs_opaque; 1713 1714 bs_opaque->is_commit = target_is_backing; 1715 1716 bdrv_drained_begin(bs); 1717 ret = bdrv_append(mirror_top_bs, bs, errp); 1718 bdrv_drained_end(bs); 1719 1720 if (ret < 0) { 1721 bdrv_unref(mirror_top_bs); 1722 return NULL; 1723 } 1724 1725 /* Make sure that the source is not resized while the job is running */ 1726 s = block_job_create(job_id, driver, NULL, mirror_top_bs, 1727 BLK_PERM_CONSISTENT_READ, 1728 BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED | 1729 BLK_PERM_WRITE, speed, 1730 creation_flags, cb, opaque, errp); 1731 if (!s) { 1732 goto fail; 1733 } 1734 1735 /* The block job now has a reference to this node */ 1736 bdrv_unref(mirror_top_bs); 1737 1738 s->mirror_top_bs = mirror_top_bs; 1739 1740 /* No resize for the target either; while the mirror is still running, a 1741 * consistent read isn't necessarily possible. We could possibly allow 1742 * writes and graph modifications, though it would likely defeat the 1743 * purpose of a mirror, so leave them blocked for now. 1744 * 1745 * In the case of active commit, things look a bit different, though, 1746 * because the target is an already populated backing file in active use. 1747 * We can allow anything except resize there.*/ 1748 1749 target_perms = BLK_PERM_WRITE; 1750 target_shared_perms = BLK_PERM_WRITE_UNCHANGED; 1751 1752 if (target_is_backing) { 1753 int64_t bs_size, target_size; 1754 bs_size = bdrv_getlength(bs); 1755 if (bs_size < 0) { 1756 error_setg_errno(errp, -bs_size, 1757 "Could not inquire top image size"); 1758 goto fail; 1759 } 1760 1761 target_size = bdrv_getlength(target); 1762 if (target_size < 0) { 1763 error_setg_errno(errp, -target_size, 1764 "Could not inquire base image size"); 1765 goto fail; 1766 } 1767 1768 if (target_size < bs_size) { 1769 target_perms |= BLK_PERM_RESIZE; 1770 } 1771 1772 target_shared_perms |= BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE; 1773 } else if (bdrv_chain_contains(bs, bdrv_skip_filters(target))) { 1774 /* 1775 * We may want to allow this in the future, but it would 1776 * require taking some extra care. 1777 */ 1778 error_setg(errp, "Cannot mirror to a filter on top of a node in the " 1779 "source's backing chain"); 1780 goto fail; 1781 } 1782 1783 s->target = blk_new(s->common.job.aio_context, 1784 target_perms, target_shared_perms); 1785 ret = blk_insert_bs(s->target, target, errp); 1786 if (ret < 0) { 1787 goto fail; 1788 } 1789 if (is_mirror) { 1790 /* XXX: Mirror target could be a NBD server of target QEMU in the case 1791 * of non-shared block migration. To allow migration completion, we 1792 * have to allow "inactivate" of the target BB. When that happens, we 1793 * know the job is drained, and the vcpus are stopped, so no write 1794 * operation will be performed. Block layer already has assertions to 1795 * ensure that. */ 1796 blk_set_force_allow_inactivate(s->target); 1797 } 1798 blk_set_allow_aio_context_change(s->target, true); 1799 blk_set_disable_request_queuing(s->target, true); 1800 1801 s->replaces = g_strdup(replaces); 1802 s->on_source_error = on_source_error; 1803 s->on_target_error = on_target_error; 1804 s->is_none_mode = is_none_mode; 1805 s->backing_mode = backing_mode; 1806 s->zero_target = zero_target; 1807 s->copy_mode = copy_mode; 1808 s->base = base; 1809 s->base_overlay = bdrv_find_overlay(bs, base); 1810 s->granularity = granularity; 1811 s->buf_size = ROUND_UP(buf_size, granularity); 1812 s->unmap = unmap; 1813 if (auto_complete) { 1814 s->should_complete = true; 1815 } 1816 1817 s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp); 1818 if (!s->dirty_bitmap) { 1819 goto fail; 1820 } 1821 if (s->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING) { 1822 bdrv_disable_dirty_bitmap(s->dirty_bitmap); 1823 } 1824 1825 ret = block_job_add_bdrv(&s->common, "source", bs, 0, 1826 BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE | 1827 BLK_PERM_CONSISTENT_READ, 1828 errp); 1829 if (ret < 0) { 1830 goto fail; 1831 } 1832 1833 /* Required permissions are already taken with blk_new() */ 1834 block_job_add_bdrv(&s->common, "target", target, 0, BLK_PERM_ALL, 1835 &error_abort); 1836 1837 /* In commit_active_start() all intermediate nodes disappear, so 1838 * any jobs in them must be blocked */ 1839 if (target_is_backing) { 1840 BlockDriverState *iter, *filtered_target; 1841 uint64_t iter_shared_perms; 1842 1843 /* 1844 * The topmost node with 1845 * bdrv_skip_filters(filtered_target) == bdrv_skip_filters(target) 1846 */ 1847 filtered_target = bdrv_cow_bs(bdrv_find_overlay(bs, target)); 1848 1849 assert(bdrv_skip_filters(filtered_target) == 1850 bdrv_skip_filters(target)); 1851 1852 /* 1853 * XXX BLK_PERM_WRITE needs to be allowed so we don't block 1854 * ourselves at s->base (if writes are blocked for a node, they are 1855 * also blocked for its backing file). The other options would be a 1856 * second filter driver above s->base (== target). 1857 */ 1858 iter_shared_perms = BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE; 1859 1860 for (iter = bdrv_filter_or_cow_bs(bs); iter != target; 1861 iter = bdrv_filter_or_cow_bs(iter)) 1862 { 1863 if (iter == filtered_target) { 1864 /* 1865 * From here on, all nodes are filters on the base. 1866 * This allows us to share BLK_PERM_CONSISTENT_READ. 1867 */ 1868 iter_shared_perms |= BLK_PERM_CONSISTENT_READ; 1869 } 1870 1871 ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0, 1872 iter_shared_perms, errp); 1873 if (ret < 0) { 1874 goto fail; 1875 } 1876 } 1877 1878 if (bdrv_freeze_backing_chain(mirror_top_bs, target, errp) < 0) { 1879 goto fail; 1880 } 1881 } 1882 1883 QTAILQ_INIT(&s->ops_in_flight); 1884 1885 trace_mirror_start(bs, s, opaque); 1886 job_start(&s->common.job); 1887 1888 return &s->common; 1889 1890 fail: 1891 if (s) { 1892 /* Make sure this BDS does not go away until we have completed the graph 1893 * changes below */ 1894 bdrv_ref(mirror_top_bs); 1895 1896 g_free(s->replaces); 1897 blk_unref(s->target); 1898 bs_opaque->job = NULL; 1899 if (s->dirty_bitmap) { 1900 bdrv_release_dirty_bitmap(s->dirty_bitmap); 1901 } 1902 job_early_fail(&s->common.job); 1903 } 1904 1905 bs_opaque->stop = true; 1906 bdrv_child_refresh_perms(mirror_top_bs, mirror_top_bs->backing, 1907 &error_abort); 1908 bdrv_replace_node(mirror_top_bs, mirror_top_bs->backing->bs, &error_abort); 1909 1910 bdrv_unref(mirror_top_bs); 1911 1912 return NULL; 1913 } 1914 1915 void mirror_start(const char *job_id, BlockDriverState *bs, 1916 BlockDriverState *target, const char *replaces, 1917 int creation_flags, int64_t speed, 1918 uint32_t granularity, int64_t buf_size, 1919 MirrorSyncMode mode, BlockMirrorBackingMode backing_mode, 1920 bool zero_target, 1921 BlockdevOnError on_source_error, 1922 BlockdevOnError on_target_error, 1923 bool unmap, const char *filter_node_name, 1924 MirrorCopyMode copy_mode, Error **errp) 1925 { 1926 bool is_none_mode; 1927 BlockDriverState *base; 1928 1929 GLOBAL_STATE_CODE(); 1930 1931 if ((mode == MIRROR_SYNC_MODE_INCREMENTAL) || 1932 (mode == MIRROR_SYNC_MODE_BITMAP)) { 1933 error_setg(errp, "Sync mode '%s' not supported", 1934 MirrorSyncMode_str(mode)); 1935 return; 1936 } 1937 is_none_mode = mode == MIRROR_SYNC_MODE_NONE; 1938 base = mode == MIRROR_SYNC_MODE_TOP ? bdrv_backing_chain_next(bs) : NULL; 1939 mirror_start_job(job_id, bs, creation_flags, target, replaces, 1940 speed, granularity, buf_size, backing_mode, zero_target, 1941 on_source_error, on_target_error, unmap, NULL, NULL, 1942 &mirror_job_driver, is_none_mode, base, false, 1943 filter_node_name, true, copy_mode, errp); 1944 } 1945 1946 BlockJob *commit_active_start(const char *job_id, BlockDriverState *bs, 1947 BlockDriverState *base, int creation_flags, 1948 int64_t speed, BlockdevOnError on_error, 1949 const char *filter_node_name, 1950 BlockCompletionFunc *cb, void *opaque, 1951 bool auto_complete, Error **errp) 1952 { 1953 bool base_read_only; 1954 BlockJob *job; 1955 1956 GLOBAL_STATE_CODE(); 1957 1958 base_read_only = bdrv_is_read_only(base); 1959 1960 if (base_read_only) { 1961 if (bdrv_reopen_set_read_only(base, false, errp) < 0) { 1962 return NULL; 1963 } 1964 } 1965 1966 job = mirror_start_job( 1967 job_id, bs, creation_flags, base, NULL, speed, 0, 0, 1968 MIRROR_LEAVE_BACKING_CHAIN, false, 1969 on_error, on_error, true, cb, opaque, 1970 &commit_active_job_driver, false, base, auto_complete, 1971 filter_node_name, false, MIRROR_COPY_MODE_BACKGROUND, 1972 errp); 1973 if (!job) { 1974 goto error_restore_flags; 1975 } 1976 1977 return job; 1978 1979 error_restore_flags: 1980 /* ignore error and errp for bdrv_reopen, because we want to propagate 1981 * the original error */ 1982 if (base_read_only) { 1983 bdrv_reopen_set_read_only(base, true, NULL); 1984 } 1985 return NULL; 1986 } 1987