block/mirror.c

   1 /*
   2  * Image mirroring
   3  *
   4  * Copyright Red Hat, Inc. 2012
   5  *
   6  * Authors:
   7  *  Paolo Bonzini  <pbonzini@redhat.com>
   8  *
   9  * This work is licensed under the terms of the GNU LGPL, version 2 or later.
  10  * See the COPYING.LIB file in the top-level directory.
  11  *
  12  */
  13
  14 #include "trace.h"
  15 #include "block/blockjob.h"
  16 #include "block/block_int.h"
  17 #include "qemu/ratelimit.h"
  18 #include "qemu/bitmap.h"
  19
  20 #define SLICE_TIME    100000000ULL /* ns */
  21 #define MAX_IN_FLIGHT 16
  22
  23 /* The mirroring buffer is a list of granularity-sized chunks.
  24  * Free chunks are organized in a list.
  25  */
  26 typedef struct MirrorBuffer {
  27     QSIMPLEQ_ENTRY(MirrorBuffer) next;
  28 } MirrorBuffer;
  29
  30 typedef struct MirrorBlockJob {
  31     BlockJob common;
  32     RateLimit limit;
  33     BlockDriverState *target;
  34     BlockDriverState *base;
  35     bool is_none_mode;
  36     BlockdevOnError on_source_error, on_target_error;
  37     bool synced;
  38     bool should_complete;
  39     int64_t sector_num;
  40     int64_t granularity;
  41     size_t buf_size;
  42     unsigned long *cow_bitmap;
  43     BdrvDirtyBitmap *dirty_bitmap;
  44     HBitmapIter hbi;
  45     uint8_t *buf;
  46     QSIMPLEQ_HEAD(, MirrorBuffer) buf_free;
  47     int buf_free_count;
  48
  49     unsigned long *in_flight_bitmap;
  50     int in_flight;
  51     int ret;
  52 } MirrorBlockJob;
  53
  54 typedef struct MirrorOp {
  55     MirrorBlockJob *s;
  56     QEMUIOVector qiov;
  57     int64_t sector_num;
  58     int nb_sectors;
  59 } MirrorOp;
  60
  61 static BlockErrorAction mirror_error_action(MirrorBlockJob *s, bool read,
  62                                             int error)
  63 {
  64     s->synced = false;
  65     if (read) {
  66         return block_job_error_action(&s->common, s->common.bs,
  67                                       s->on_source_error, true, error);
  68     } else {
  69         return block_job_error_action(&s->common, s->target,
  70                                       s->on_target_error, false, error);
  71     }
  72 }
  73
  74 static void mirror_iteration_done(MirrorOp *op, int ret)
  75 {
  76     MirrorBlockJob *s = op->s;
  77     struct iovec *iov;
  78     int64_t chunk_num;
  79     int i, nb_chunks, sectors_per_chunk;
  80
  81     trace_mirror_iteration_done(s, op->sector_num, op->nb_sectors, ret);
  82
  83     s->in_flight--;
  84     iov = op->qiov.iov;
  85     for (i = 0; i < op->qiov.niov; i++) {
  86         MirrorBuffer *buf = (MirrorBuffer *) iov[i].iov_base;
  87         QSIMPLEQ_INSERT_TAIL(&s->buf_free, buf, next);
  88         s->buf_free_count++;
  89     }
  90
  91     sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
  92     chunk_num = op->sector_num / sectors_per_chunk;
  93     nb_chunks = op->nb_sectors / sectors_per_chunk;
  94     bitmap_clear(s->in_flight_bitmap, chunk_num, nb_chunks);
  95     if (s->cow_bitmap && ret >= 0) {
  96         bitmap_set(s->cow_bitmap, chunk_num, nb_chunks);
  97     }
  98
  99     g_slice_free(MirrorOp, op);
 100     qemu_coroutine_enter(s->common.co, NULL);
 101 }
 102
 103 static void mirror_write_complete(void *opaque, int ret)
 104 {
 105     MirrorOp *op = opaque;
 106     MirrorBlockJob *s = op->s;
 107     if (ret < 0) {
 108         BlockDriverState *source = s->common.bs;
 109         BlockErrorAction action;
 110
 111         bdrv_set_dirty(source, op->sector_num, op->nb_sectors);
 112         action = mirror_error_action(s, false, -ret);
 113         if (action == BDRV_ACTION_REPORT && s->ret >= 0) {
 114             s->ret = ret;
 115         }
 116     }
 117     mirror_iteration_done(op, ret);
 118 }
 119
 120 static void mirror_read_complete(void *opaque, int ret)
 121 {
 122     MirrorOp *op = opaque;
 123     MirrorBlockJob *s = op->s;
 124     if (ret < 0) {
 125         BlockDriverState *source = s->common.bs;
 126         BlockErrorAction action;
 127
 128         bdrv_set_dirty(source, op->sector_num, op->nb_sectors);
 129         action = mirror_error_action(s, true, -ret);
 130         if (action == BDRV_ACTION_REPORT && s->ret >= 0) {
 131             s->ret = ret;
 132         }
 133
 134         mirror_iteration_done(op, ret);
 135         return;
 136     }
 137     bdrv_aio_writev(s->target, op->sector_num, &op->qiov, op->nb_sectors,
 138                     mirror_write_complete, op);
 139 }
 140
 141 static void coroutine_fn mirror_iteration(MirrorBlockJob *s)
 142 {
 143     BlockDriverState *source = s->common.bs;
 144     int nb_sectors, sectors_per_chunk, nb_chunks;
 145     int64_t end, sector_num, next_chunk, next_sector, hbitmap_next_sector;
 146     MirrorOp *op;
 147
 148     s->sector_num = hbitmap_iter_next(&s->hbi);
 149     if (s->sector_num < 0) {
 150         bdrv_dirty_iter_init(source, s->dirty_bitmap, &s->hbi);
 151         s->sector_num = hbitmap_iter_next(&s->hbi);
 152         trace_mirror_restart_iter(s,
 153                                   bdrv_get_dirty_count(source, s->dirty_bitmap));
 154         assert(s->sector_num >= 0);
 155     }
 156
 157     hbitmap_next_sector = s->sector_num;
 158     sector_num = s->sector_num;
 159     sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
 160     end = s->common.len >> BDRV_SECTOR_BITS;
 161
 162     /* Extend the QEMUIOVector to include all adjacent blocks that will
 163      * be copied in this operation.
 164      *
 165      * We have to do this if we have no backing file yet in the destination,
 166      * and the cluster size is very large.  Then we need to do COW ourselves.
 167      * The first time a cluster is copied, copy it entirely.  Note that,
 168      * because both the granularity and the cluster size are powers of two,
 169      * the number of sectors to copy cannot exceed one cluster.
 170      *
 171      * We also want to extend the QEMUIOVector to include more adjacent
 172      * dirty blocks if possible, to limit the number of I/O operations and
 173      * run efficiently even with a small granularity.
 174      */
 175     nb_chunks = 0;
 176     nb_sectors = 0;
 177     next_sector = sector_num;
 178     next_chunk = sector_num / sectors_per_chunk;
 179
 180     /* Wait for I/O to this cluster (from a previous iteration) to be done.  */
 181     while (test_bit(next_chunk, s->in_flight_bitmap)) {
 182         trace_mirror_yield_in_flight(s, sector_num, s->in_flight);
 183         qemu_coroutine_yield();
 184     }
 185
 186     do {
 187         int added_sectors, added_chunks;
 188
 189         if (!bdrv_get_dirty(source, s->dirty_bitmap, next_sector) ||
 190             test_bit(next_chunk, s->in_flight_bitmap)) {
 191             assert(nb_sectors > 0);
 192             break;
 193         }
 194
 195         added_sectors = sectors_per_chunk;
 196         if (s->cow_bitmap && !test_bit(next_chunk, s->cow_bitmap)) {
 197             bdrv_round_to_clusters(s->target,
 198                                    next_sector, added_sectors,
 199                                    &next_sector, &added_sectors);
 200
 201             /* On the first iteration, the rounding may make us copy
 202              * sectors before the first dirty one.
 203              */
 204             if (next_sector < sector_num) {
 205                 assert(nb_sectors == 0);
 206                 sector_num = next_sector;
 207                 next_chunk = next_sector / sectors_per_chunk;
 208             }
 209         }
 210
 211         added_sectors = MIN(added_sectors, end - (sector_num + nb_sectors));
 212         added_chunks = (added_sectors + sectors_per_chunk - 1) / sectors_per_chunk;
 213
 214         /* When doing COW, it may happen that there is not enough space for
 215          * a full cluster.  Wait if that is the case.
 216          */
 217         while (nb_chunks == 0 && s->buf_free_count < added_chunks) {
 218             trace_mirror_yield_buf_busy(s, nb_chunks, s->in_flight);
 219             qemu_coroutine_yield();
 220         }
 221         if (s->buf_free_count < nb_chunks + added_chunks) {
 222             trace_mirror_break_buf_busy(s, nb_chunks, s->in_flight);
 223             break;
 224         }
 225
 226         /* We have enough free space to copy these sectors.  */
 227         bitmap_set(s->in_flight_bitmap, next_chunk, added_chunks);
 228
 229         nb_sectors += added_sectors;
 230         nb_chunks += added_chunks;
 231         next_sector += added_sectors;
 232         next_chunk += added_chunks;
 233     } while (next_sector < end);
 234
 235     /* Allocate a MirrorOp that is used as an AIO callback.  */
 236     op = g_slice_new(MirrorOp);
 237     op->s = s;
 238     op->sector_num = sector_num;
 239     op->nb_sectors = nb_sectors;
 240
 241     /* Now make a QEMUIOVector taking enough granularity-sized chunks
 242      * from s->buf_free.
 243      */
 244     qemu_iovec_init(&op->qiov, nb_chunks);
 245     next_sector = sector_num;
 246     while (nb_chunks-- > 0) {
 247         MirrorBuffer *buf = QSIMPLEQ_FIRST(&s->buf_free);
 248         QSIMPLEQ_REMOVE_HEAD(&s->buf_free, next);
 249         s->buf_free_count--;
 250         qemu_iovec_add(&op->qiov, buf, s->granularity);
 251
 252         /* Advance the HBitmapIter in parallel, so that we do not examine
 253          * the same sector twice.
 254          */
 255         if (next_sector > hbitmap_next_sector
 256             && bdrv_get_dirty(source, s->dirty_bitmap, next_sector)) {
 257             hbitmap_next_sector = hbitmap_iter_next(&s->hbi);
 258         }
 259
 260         next_sector += sectors_per_chunk;
 261     }
 262
 263     bdrv_reset_dirty(source, sector_num, nb_sectors);
 264
 265     /* Copy the dirty cluster.  */
 266     s->in_flight++;
 267     trace_mirror_one_iteration(s, sector_num, nb_sectors);
 268     bdrv_aio_readv(source, sector_num, &op->qiov, nb_sectors,
 269                    mirror_read_complete, op);
 270 }
 271
 272 static void mirror_free_init(MirrorBlockJob *s)
 273 {
 274     int granularity = s->granularity;
 275     size_t buf_size = s->buf_size;
 276     uint8_t *buf = s->buf;
 277
 278     assert(s->buf_free_count == 0);
 279     QSIMPLEQ_INIT(&s->buf_free);
 280     while (buf_size != 0) {
 281         MirrorBuffer *cur = (MirrorBuffer *)buf;
 282         QSIMPLEQ_INSERT_TAIL(&s->buf_free, cur, next);
 283         s->buf_free_count++;
 284         buf_size -= granularity;
 285         buf += granularity;
 286     }
 287 }
 288
 289 static void mirror_drain(MirrorBlockJob *s)
 290 {
 291     while (s->in_flight > 0) {
 292         qemu_coroutine_yield();
 293     }
 294 }
 295
 296 static void coroutine_fn mirror_run(void *opaque)
 297 {
 298     MirrorBlockJob *s = opaque;
 299     BlockDriverState *bs = s->common.bs;
 300     int64_t sector_num, end, sectors_per_chunk, length;
 301     uint64_t last_pause_ns;
 302     BlockDriverInfo bdi;
 303     char backing_filename[1024];
 304     int ret = 0;
 305     int n;
 306
 307     if (block_job_is_cancelled(&s->common)) {
 308         goto immediate_exit;
 309     }
 310
 311     s->common.len = bdrv_getlength(bs);
 312     if (s->common.len <= 0) {
 313         block_job_completed(&s->common, s->common.len);
 314         return;
 315     }
 316
 317     length = (bdrv_getlength(bs) + s->granularity - 1) / s->granularity;
 318     s->in_flight_bitmap = bitmap_new(length);
 319
 320     /* If we have no backing file yet in the destination, we cannot let
 321      * the destination do COW.  Instead, we copy sectors around the
 322      * dirty data if needed.  We need a bitmap to do that.
 323      */
 324     bdrv_get_backing_filename(s->target, backing_filename,
 325                               sizeof(backing_filename));
 326     if (backing_filename[0] && !s->target->backing_hd) {
 327         bdrv_get_info(s->target, &bdi);
 328         if (s->granularity < bdi.cluster_size) {
 329             s->buf_size = MAX(s->buf_size, bdi.cluster_size);
 330             s->cow_bitmap = bitmap_new(length);
 331         }
 332     }
 333
 334     end = s->common.len >> BDRV_SECTOR_BITS;
 335     s->buf = qemu_blockalign(bs, s->buf_size);
 336     sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
 337     mirror_free_init(s);
 338
 339     if (!s->is_none_mode) {
 340         /* First part, loop on the sectors and initialize the dirty bitmap.  */
 341         BlockDriverState *base = s->base;
 342         for (sector_num = 0; sector_num < end; ) {
 343             int64_t next = (sector_num | (sectors_per_chunk - 1)) + 1;
 344             ret = bdrv_is_allocated_above(bs, base,
 345                                           sector_num, next - sector_num, &n);
 346
 347             if (ret < 0) {
 348                 goto immediate_exit;
 349             }
 350
 351             assert(n > 0);
 352             if (ret == 1) {
 353                 bdrv_set_dirty(bs, sector_num, n);
 354                 sector_num = next;
 355             } else {
 356                 sector_num += n;
 357             }
 358         }
 359     }
 360
 361     bdrv_dirty_iter_init(bs, s->dirty_bitmap, &s->hbi);
 362     last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
 363     for (;;) {
 364         uint64_t delay_ns;
 365         int64_t cnt;
 366         bool should_complete;
 367
 368         if (s->ret < 0) {
 369             ret = s->ret;
 370             goto immediate_exit;
 371         }
 372
 373         cnt = bdrv_get_dirty_count(bs, s->dirty_bitmap);
 374
 375         /* Note that even when no rate limit is applied we need to yield
 376          * periodically with no pending I/O so that qemu_aio_flush() returns.
 377          * We do so every SLICE_TIME nanoseconds, or when there is an error,
 378          * or when the source is clean, whichever comes first.
 379          */
 380         if (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - last_pause_ns < SLICE_TIME &&
 381             s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
 382             if (s->in_flight == MAX_IN_FLIGHT || s->buf_free_count == 0 ||
 383                 (cnt == 0 && s->in_flight > 0)) {
 384                 trace_mirror_yield(s, s->in_flight, s->buf_free_count, cnt);
 385                 qemu_coroutine_yield();
 386                 continue;
 387             } else if (cnt != 0) {
 388                 mirror_iteration(s);
 389                 continue;
 390             }
 391         }
 392
 393         should_complete = false;
 394         if (s->in_flight == 0 && cnt == 0) {
 395             trace_mirror_before_flush(s);
 396             ret = bdrv_flush(s->target);
 397             if (ret < 0) {
 398                 if (mirror_error_action(s, false, -ret) == BDRV_ACTION_REPORT) {
 399                     goto immediate_exit;
 400                 }
 401             } else {
 402                 /* We're out of the streaming phase.  From now on, if the job
 403                  * is cancelled we will actually complete all pending I/O and
 404                  * report completion.  This way, block-job-cancel will leave
 405                  * the target in a consistent state.
 406                  */
 407                 s->common.offset = end * BDRV_SECTOR_SIZE;
 408                 if (!s->synced) {
 409                     block_job_ready(&s->common);
 410                     s->synced = true;
 411                 }
 412
 413                 should_complete = s->should_complete ||
 414                     block_job_is_cancelled(&s->common);
 415                 cnt = bdrv_get_dirty_count(bs, s->dirty_bitmap);
 416             }
 417         }
 418
 419         if (cnt == 0 && should_complete) {
 420             /* The dirty bitmap is not updated while operations are pending.
 421              * If we're about to exit, wait for pending operations before
 422              * calling bdrv_get_dirty_count(bs), or we may exit while the
 423              * source has dirty data to copy!
 424              *
 425              * Note that I/O can be submitted by the guest while
 426              * mirror_populate runs.
 427              */
 428             trace_mirror_before_drain(s, cnt);
 429             bdrv_drain_all();
 430             cnt = bdrv_get_dirty_count(bs, s->dirty_bitmap);
 431         }
 432
 433         ret = 0;
 434         trace_mirror_before_sleep(s, cnt, s->synced);
 435         if (!s->synced) {
 436             /* Publish progress */
 437             s->common.offset = (end - cnt) * BDRV_SECTOR_SIZE;
 438
 439             if (s->common.speed) {
 440                 delay_ns = ratelimit_calculate_delay(&s->limit, sectors_per_chunk);
 441             } else {
 442                 delay_ns = 0;
 443             }
 444
 445             block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns);
 446             if (block_job_is_cancelled(&s->common)) {
 447                 break;
 448             }
 449         } else if (!should_complete) {
 450             delay_ns = (s->in_flight == 0 && cnt == 0 ? SLICE_TIME : 0);
 451             block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns);
 452         } else if (cnt == 0) {
 453             /* The two disks are in sync.  Exit and report successful
 454              * completion.
 455              */
 456             assert(QLIST_EMPTY(&bs->tracked_requests));
 457             s->common.cancelled = false;
 458             break;
 459         }
 460         last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
 461     }
 462
 463 immediate_exit:
 464     if (s->in_flight > 0) {
 465         /* We get here only if something went wrong.  Either the job failed,
 466          * or it was cancelled prematurely so that we do not guarantee that
 467          * the target is a copy of the source.
 468          */
 469         assert(ret < 0 || (!s->synced && block_job_is_cancelled(&s->common)));
 470         mirror_drain(s);
 471     }
 472
 473     assert(s->in_flight == 0);
 474     qemu_vfree(s->buf);
 475     g_free(s->cow_bitmap);
 476     g_free(s->in_flight_bitmap);
 477     bdrv_release_dirty_bitmap(bs, s->dirty_bitmap);
 478     bdrv_iostatus_disable(s->target);
 479     if (s->should_complete && ret == 0) {
 480         if (bdrv_get_flags(s->target) != bdrv_get_flags(s->common.bs)) {
 481             bdrv_reopen(s->target, bdrv_get_flags(s->common.bs), NULL);
 482         }
 483         bdrv_swap(s->target, s->common.bs);
 484         if (s->common.driver->job_type == BLOCK_JOB_TYPE_COMMIT) {
 485             /* drop the bs loop chain formed by the swap: break the loop then
 486              * trigger the unref from the top one */
 487             BlockDriverState *p = s->base->backing_hd;
 488             s->base->backing_hd = NULL;
 489             bdrv_unref(p);
 490         }
 491     }
 492     bdrv_unref(s->target);
 493     block_job_completed(&s->common, ret);
 494 }
 495
 496 static void mirror_set_speed(BlockJob *job, int64_t speed, Error **errp)
 497 {
 498     MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
 499
 500     if (speed < 0) {
 501         error_set(errp, QERR_INVALID_PARAMETER, "speed");
 502         return;
 503     }
 504     ratelimit_set_speed(&s->limit, speed / BDRV_SECTOR_SIZE, SLICE_TIME);
 505 }
 506
 507 static void mirror_iostatus_reset(BlockJob *job)
 508 {
 509     MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
 510
 511     bdrv_iostatus_reset(s->target);
 512 }
 513
 514 static void mirror_complete(BlockJob *job, Error **errp)
 515 {
 516     MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
 517     Error *local_err = NULL;
 518     int ret;
 519
 520     ret = bdrv_open_backing_file(s->target, NULL, &local_err);
 521     if (ret < 0) {
 522         char backing_filename[PATH_MAX];
 523         bdrv_get_full_backing_filename(s->target, backing_filename,
 524                                        sizeof(backing_filename));
 525         error_propagate(errp, local_err);
 526         return;
 527     }
 528     if (!s->synced) {
 529         error_set(errp, QERR_BLOCK_JOB_NOT_READY, job->bs->device_name);
 530         return;
 531     }
 532
 533     s->should_complete = true;
 534     block_job_resume(job);
 535 }
 536
 537 static const BlockJobDriver mirror_job_driver = {
 538     .instance_size = sizeof(MirrorBlockJob),
 539     .job_type      = BLOCK_JOB_TYPE_MIRROR,
 540     .set_speed     = mirror_set_speed,
 541     .iostatus_reset= mirror_iostatus_reset,
 542     .complete      = mirror_complete,
 543 };
 544
 545 static const BlockJobDriver commit_active_job_driver = {
 546     .instance_size = sizeof(MirrorBlockJob),
 547     .job_type      = BLOCK_JOB_TYPE_COMMIT,
 548     .set_speed     = mirror_set_speed,
 549     .iostatus_reset
 550                    = mirror_iostatus_reset,
 551     .complete      = mirror_complete,
 552 };
 553
 554 static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target,
 555                             int64_t speed, int64_t granularity,
 556                             int64_t buf_size,
 557                             BlockdevOnError on_source_error,
 558                             BlockdevOnError on_target_error,
 559                             BlockDriverCompletionFunc *cb,
 560                             void *opaque, Error **errp,
 561                             const BlockJobDriver *driver,
 562                             bool is_none_mode, BlockDriverState *base)
 563 {
 564     MirrorBlockJob *s;
 565
 566     if (granularity == 0) {
 567         /* Choose the default granularity based on the target file's cluster
 568          * size, clamped between 4k and 64k.  */
 569         BlockDriverInfo bdi;
 570         if (bdrv_get_info(target, &bdi) >= 0 && bdi.cluster_size != 0) {
 571             granularity = MAX(4096, bdi.cluster_size);
 572             granularity = MIN(65536, granularity);
 573         } else {
 574             granularity = 65536;
 575         }
 576     }
 577
 578     assert ((granularity & (granularity - 1)) == 0);
 579
 580     if ((on_source_error == BLOCKDEV_ON_ERROR_STOP ||
 581          on_source_error == BLOCKDEV_ON_ERROR_ENOSPC) &&
 582         !bdrv_iostatus_is_enabled(bs)) {
 583         error_set(errp, QERR_INVALID_PARAMETER, "on-source-error");
 584         return;
 585     }
 586
 587
 588     s = block_job_create(driver, bs, speed, cb, opaque, errp);
 589     if (!s) {
 590         return;
 591     }
 592
 593     s->on_source_error = on_source_error;
 594     s->on_target_error = on_target_error;
 595     s->target = target;
 596     s->is_none_mode = is_none_mode;
 597     s->base = base;
 598     s->granularity = granularity;
 599     s->buf_size = MAX(buf_size, granularity);
 600
 601     s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity);
 602     bdrv_set_enable_write_cache(s->target, true);
 603     bdrv_set_on_error(s->target, on_target_error, on_target_error);
 604     bdrv_iostatus_enable(s->target);
 605     s->common.co = qemu_coroutine_create(mirror_run);
 606     trace_mirror_start(bs, s, s->common.co, opaque);
 607     qemu_coroutine_enter(s->common.co, s);
 608 }
 609
 610 void mirror_start(BlockDriverState *bs, BlockDriverState *target,
 611                   int64_t speed, int64_t granularity, int64_t buf_size,
 612                   MirrorSyncMode mode, BlockdevOnError on_source_error,
 613                   BlockdevOnError on_target_error,
 614                   BlockDriverCompletionFunc *cb,
 615                   void *opaque, Error **errp)
 616 {
 617     bool is_none_mode;
 618     BlockDriverState *base;
 619
 620     is_none_mode = mode == MIRROR_SYNC_MODE_NONE;
 621     base = mode == MIRROR_SYNC_MODE_TOP ? bs->backing_hd : NULL;
 622     mirror_start_job(bs, target, speed, granularity, buf_size,
 623                      on_source_error, on_target_error, cb, opaque, errp,
 624                      &mirror_job_driver, is_none_mode, base);
 625 }
 626
 627 void commit_active_start(BlockDriverState *bs, BlockDriverState *base,
 628                          int64_t speed,
 629                          BlockdevOnError on_error,
 630                          BlockDriverCompletionFunc *cb,
 631                          void *opaque, Error **errp)
 632 {
 633     if (bdrv_reopen(base, bs->open_flags, errp)) {
 634         return;
 635     }
 636     bdrv_ref(base);
 637     mirror_start_job(bs, base, speed, 0, 0,
 638                      on_error, on_error, cb, opaque, errp,
 639                      &commit_active_job_driver, false, base);
 640 }