block/replication.c

   1 /*
   2  * Replication Block filter
   3  *
   4  * Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
   5  * Copyright (c) 2016 Intel Corporation
   6  * Copyright (c) 2016 FUJITSU LIMITED
   7  *
   8  * Author:
   9  *   Wen Congyang <[email protected]>
  10  *
  11  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  12  * See the COPYING file in the top-level directory.
  13  */
  14
  15 #include "qemu/osdep.h"
  16 #include "qemu-common.h"
  17 #include "block/nbd.h"
  18 #include "block/blockjob.h"
  19 #include "block/block_int.h"
  20 #include "block/block_backup.h"
  21 #include "sysemu/block-backend.h"
  22 #include "qapi/error.h"
  23 #include "replication.h"
  24
  25 typedef enum {
  26     BLOCK_REPLICATION_NONE,             /* block replication is not started */
  27     BLOCK_REPLICATION_RUNNING,          /* block replication is running */
  28     BLOCK_REPLICATION_FAILOVER,         /* failover is running in background */
  29     BLOCK_REPLICATION_FAILOVER_FAILED,  /* failover failed */
  30     BLOCK_REPLICATION_DONE,             /* block replication is done */
  31 } ReplicationStage;
  32
  33 typedef struct BDRVReplicationState {
  34     ReplicationMode mode;
  35     ReplicationStage stage;
  36     BdrvChild *active_disk;
  37     BdrvChild *hidden_disk;
  38     BdrvChild *secondary_disk;
  39     char *top_id;
  40     ReplicationState *rs;
  41     Error *blocker;
  42     int orig_hidden_flags;
  43     int orig_secondary_flags;
  44     int error;
  45 } BDRVReplicationState;
  46
  47 static void replication_start(ReplicationState *rs, ReplicationMode mode,
  48                               Error **errp);
  49 static void replication_do_checkpoint(ReplicationState *rs, Error **errp);
  50 static void replication_get_error(ReplicationState *rs, Error **errp);
  51 static void replication_stop(ReplicationState *rs, bool failover,
  52                              Error **errp);
  53
  54 #define REPLICATION_MODE        "mode"
  55 #define REPLICATION_TOP_ID      "top-id"
  56 static QemuOptsList replication_runtime_opts = {
  57     .name = "replication",
  58     .head = QTAILQ_HEAD_INITIALIZER(replication_runtime_opts.head),
  59     .desc = {
  60         {
  61             .name = REPLICATION_MODE,
  62             .type = QEMU_OPT_STRING,
  63         },
  64         {
  65             .name = REPLICATION_TOP_ID,
  66             .type = QEMU_OPT_STRING,
  67         },
  68         { /* end of list */ }
  69     },
  70 };
  71
  72 static ReplicationOps replication_ops = {
  73     .start = replication_start,
  74     .checkpoint = replication_do_checkpoint,
  75     .get_error = replication_get_error,
  76     .stop = replication_stop,
  77 };
  78
  79 static int replication_open(BlockDriverState *bs, QDict *options,
  80                             int flags, Error **errp)
  81 {
  82     int ret;
  83     BDRVReplicationState *s = bs->opaque;
  84     Error *local_err = NULL;
  85     QemuOpts *opts = NULL;
  86     const char *mode;
  87     const char *top_id;
  88
  89     bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
  90                                false, errp);
  91     if (!bs->file) {
  92         return -EINVAL;
  93     }
  94
  95     ret = -EINVAL;
  96     opts = qemu_opts_create(&replication_runtime_opts, NULL, 0, &error_abort);
  97     qemu_opts_absorb_qdict(opts, options, &local_err);
  98     if (local_err) {
  99         goto fail;
 100     }
 101
 102     mode = qemu_opt_get(opts, REPLICATION_MODE);
 103     if (!mode) {
 104         error_setg(&local_err, "Missing the option mode");
 105         goto fail;
 106     }
 107
 108     if (!strcmp(mode, "primary")) {
 109         s->mode = REPLICATION_MODE_PRIMARY;
 110         top_id = qemu_opt_get(opts, REPLICATION_TOP_ID);
 111         if (top_id) {
 112             error_setg(&local_err, "The primary side does not support option top-id");
 113             goto fail;
 114         }
 115     } else if (!strcmp(mode, "secondary")) {
 116         s->mode = REPLICATION_MODE_SECONDARY;
 117         top_id = qemu_opt_get(opts, REPLICATION_TOP_ID);
 118         s->top_id = g_strdup(top_id);
 119         if (!s->top_id) {
 120             error_setg(&local_err, "Missing the option top-id");
 121             goto fail;
 122         }
 123     } else {
 124         error_setg(&local_err,
 125                    "The option mode's value should be primary or secondary");
 126         goto fail;
 127     }
 128
 129     s->rs = replication_new(bs, &replication_ops);
 130
 131     ret = 0;
 132
 133 fail:
 134     qemu_opts_del(opts);
 135     error_propagate(errp, local_err);
 136
 137     return ret;
 138 }
 139
 140 static void replication_close(BlockDriverState *bs)
 141 {
 142     BDRVReplicationState *s = bs->opaque;
 143
 144     if (s->stage == BLOCK_REPLICATION_RUNNING) {
 145         replication_stop(s->rs, false, NULL);
 146     }
 147     if (s->stage == BLOCK_REPLICATION_FAILOVER) {
 148         block_job_cancel_sync(s->active_disk->bs->job);
 149     }
 150
 151     if (s->mode == REPLICATION_MODE_SECONDARY) {
 152         g_free(s->top_id);
 153     }
 154
 155     replication_remove(s->rs);
 156 }
 157
 158 static void replication_child_perm(BlockDriverState *bs, BdrvChild *c,
 159                                    const BdrvChildRole *role,
 160                                    BlockReopenQueue *reopen_queue,
 161                                    uint64_t perm, uint64_t shared,
 162                                    uint64_t *nperm, uint64_t *nshared)
 163 {
 164     *nperm = BLK_PERM_CONSISTENT_READ;
 165     if ((bs->open_flags & (BDRV_O_INACTIVE | BDRV_O_RDWR)) == BDRV_O_RDWR) {
 166         *nperm |= BLK_PERM_WRITE;
 167     }
 168     *nshared = BLK_PERM_CONSISTENT_READ \
 169                | BLK_PERM_WRITE \
 170                | BLK_PERM_WRITE_UNCHANGED;
 171     return;
 172 }
 173
 174 static int64_t replication_getlength(BlockDriverState *bs)
 175 {
 176     return bdrv_getlength(bs->file->bs);
 177 }
 178
 179 static int replication_get_io_status(BDRVReplicationState *s)
 180 {
 181     switch (s->stage) {
 182     case BLOCK_REPLICATION_NONE:
 183         return -EIO;
 184     case BLOCK_REPLICATION_RUNNING:
 185         return 0;
 186     case BLOCK_REPLICATION_FAILOVER:
 187         return s->mode == REPLICATION_MODE_PRIMARY ? -EIO : 0;
 188     case BLOCK_REPLICATION_FAILOVER_FAILED:
 189         return s->mode == REPLICATION_MODE_PRIMARY ? -EIO : 1;
 190     case BLOCK_REPLICATION_DONE:
 191         /*
 192          * active commit job completes, and active disk and secondary_disk
 193          * is swapped, so we can operate bs->file directly
 194          */
 195         return s->mode == REPLICATION_MODE_PRIMARY ? -EIO : 0;
 196     default:
 197         abort();
 198     }
 199 }
 200
 201 static int replication_return_value(BDRVReplicationState *s, int ret)
 202 {
 203     if (s->mode == REPLICATION_MODE_SECONDARY) {
 204         return ret;
 205     }
 206
 207     if (ret < 0) {
 208         s->error = ret;
 209         ret = 0;
 210     }
 211
 212     return ret;
 213 }
 214
 215 static coroutine_fn int replication_co_readv(BlockDriverState *bs,
 216                                              int64_t sector_num,
 217                                              int remaining_sectors,
 218                                              QEMUIOVector *qiov)
 219 {
 220     BDRVReplicationState *s = bs->opaque;
 221     BdrvChild *child = s->secondary_disk;
 222     BlockJob *job = NULL;
 223     CowRequest req;
 224     int ret;
 225
 226     if (s->mode == REPLICATION_MODE_PRIMARY) {
 227         /* We only use it to forward primary write requests */
 228         return -EIO;
 229     }
 230
 231     ret = replication_get_io_status(s);
 232     if (ret < 0) {
 233         return ret;
 234     }
 235
 236     if (child && child->bs) {
 237         job = child->bs->job;
 238     }
 239
 240     if (job) {
 241         uint64_t remaining_bytes = remaining_sectors * BDRV_SECTOR_SIZE;
 242
 243         backup_wait_for_overlapping_requests(child->bs->job,
 244                                              sector_num * BDRV_SECTOR_SIZE,
 245                                              remaining_bytes);
 246         backup_cow_request_begin(&req, child->bs->job,
 247                                  sector_num * BDRV_SECTOR_SIZE,
 248                                  remaining_bytes);
 249         ret = bdrv_co_readv(bs->file, sector_num, remaining_sectors,
 250                             qiov);
 251         backup_cow_request_end(&req);
 252         goto out;
 253     }
 254
 255     ret = bdrv_co_readv(bs->file, sector_num, remaining_sectors, qiov);
 256 out:
 257     return replication_return_value(s, ret);
 258 }
 259
 260 static coroutine_fn int replication_co_writev(BlockDriverState *bs,
 261                                               int64_t sector_num,
 262                                               int remaining_sectors,
 263                                               QEMUIOVector *qiov)
 264 {
 265     BDRVReplicationState *s = bs->opaque;
 266     QEMUIOVector hd_qiov;
 267     uint64_t bytes_done = 0;
 268     BdrvChild *top = bs->file;
 269     BdrvChild *base = s->secondary_disk;
 270     BdrvChild *target;
 271     int ret;
 272     int64_t n;
 273
 274     ret = replication_get_io_status(s);
 275     if (ret < 0) {
 276         goto out;
 277     }
 278
 279     if (ret == 0) {
 280         ret = bdrv_co_writev(top, sector_num,
 281                              remaining_sectors, qiov);
 282         return replication_return_value(s, ret);
 283     }
 284
 285     /*
 286      * Failover failed, only write to active disk if the sectors
 287      * have already been allocated in active disk/hidden disk.
 288      */
 289     qemu_iovec_init(&hd_qiov, qiov->niov);
 290     while (remaining_sectors > 0) {
 291         int64_t count;
 292
 293         ret = bdrv_is_allocated_above(top->bs, base->bs,
 294                                       sector_num * BDRV_SECTOR_SIZE,
 295                                       remaining_sectors * BDRV_SECTOR_SIZE,
 296                                       &count);
 297         if (ret < 0) {
 298             goto out1;
 299         }
 300
 301         assert(QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE));
 302         n = count >> BDRV_SECTOR_BITS;
 303         qemu_iovec_reset(&hd_qiov);
 304         qemu_iovec_concat(&hd_qiov, qiov, bytes_done, count);
 305
 306         target = ret ? top : base;
 307         ret = bdrv_co_writev(target, sector_num, n, &hd_qiov);
 308         if (ret < 0) {
 309             goto out1;
 310         }
 311
 312         remaining_sectors -= n;
 313         sector_num += n;
 314         bytes_done += count;
 315     }
 316
 317 out1:
 318     qemu_iovec_destroy(&hd_qiov);
 319 out:
 320     return ret;
 321 }
 322
 323 static bool replication_recurse_is_first_non_filter(BlockDriverState *bs,
 324                                                     BlockDriverState *candidate)
 325 {
 326     return bdrv_recurse_is_first_non_filter(bs->file->bs, candidate);
 327 }
 328
 329 static void secondary_do_checkpoint(BDRVReplicationState *s, Error **errp)
 330 {
 331     Error *local_err = NULL;
 332     int ret;
 333
 334     if (!s->secondary_disk->bs->job) {
 335         error_setg(errp, "Backup job was cancelled unexpectedly");
 336         return;
 337     }
 338
 339     backup_do_checkpoint(s->secondary_disk->bs->job, &local_err);
 340     if (local_err) {
 341         error_propagate(errp, local_err);
 342         return;
 343     }
 344
 345     if (!s->active_disk->bs->drv) {
 346         error_setg(errp, "Active disk %s is ejected",
 347                    s->active_disk->bs->node_name);
 348         return;
 349     }
 350
 351     ret = s->active_disk->bs->drv->bdrv_make_empty(s->active_disk->bs);
 352     if (ret < 0) {
 353         error_setg(errp, "Cannot make active disk empty");
 354         return;
 355     }
 356
 357     if (!s->hidden_disk->bs->drv) {
 358         error_setg(errp, "Hidden disk %s is ejected",
 359                    s->hidden_disk->bs->node_name);
 360         return;
 361     }
 362
 363     ret = s->hidden_disk->bs->drv->bdrv_make_empty(s->hidden_disk->bs);
 364     if (ret < 0) {
 365         error_setg(errp, "Cannot make hidden disk empty");
 366         return;
 367     }
 368 }
 369
 370 static void reopen_backing_file(BlockDriverState *bs, bool writable,
 371                                 Error **errp)
 372 {
 373     BDRVReplicationState *s = bs->opaque;
 374     BlockReopenQueue *reopen_queue = NULL;
 375     int orig_hidden_flags, orig_secondary_flags;
 376     int new_hidden_flags, new_secondary_flags;
 377     Error *local_err = NULL;
 378
 379     if (writable) {
 380         orig_hidden_flags = s->orig_hidden_flags =
 381                                 bdrv_get_flags(s->hidden_disk->bs);
 382         new_hidden_flags = (orig_hidden_flags | BDRV_O_RDWR) &
 383                                                     ~BDRV_O_INACTIVE;
 384         orig_secondary_flags = s->orig_secondary_flags =
 385                                 bdrv_get_flags(s->secondary_disk->bs);
 386         new_secondary_flags = (orig_secondary_flags | BDRV_O_RDWR) &
 387                                                      ~BDRV_O_INACTIVE;
 388     } else {
 389         orig_hidden_flags = (s->orig_hidden_flags | BDRV_O_RDWR) &
 390                                                     ~BDRV_O_INACTIVE;
 391         new_hidden_flags = s->orig_hidden_flags;
 392         orig_secondary_flags = (s->orig_secondary_flags | BDRV_O_RDWR) &
 393                                                     ~BDRV_O_INACTIVE;
 394         new_secondary_flags = s->orig_secondary_flags;
 395     }
 396
 397     if (orig_hidden_flags != new_hidden_flags) {
 398         reopen_queue = bdrv_reopen_queue(reopen_queue, s->hidden_disk->bs, NULL,
 399                                          new_hidden_flags);
 400     }
 401
 402     if (!(orig_secondary_flags & BDRV_O_RDWR)) {
 403         reopen_queue = bdrv_reopen_queue(reopen_queue, s->secondary_disk->bs,
 404                                          NULL, new_secondary_flags);
 405     }
 406
 407     if (reopen_queue) {
 408         bdrv_reopen_multiple(bdrv_get_aio_context(bs),
 409                              reopen_queue, &local_err);
 410         error_propagate(errp, local_err);
 411     }
 412 }
 413
 414 static void backup_job_cleanup(BlockDriverState *bs)
 415 {
 416     BDRVReplicationState *s = bs->opaque;
 417     BlockDriverState *top_bs;
 418
 419     top_bs = bdrv_lookup_bs(s->top_id, s->top_id, NULL);
 420     if (!top_bs) {
 421         return;
 422     }
 423     bdrv_op_unblock_all(top_bs, s->blocker);
 424     error_free(s->blocker);
 425     reopen_backing_file(bs, false, NULL);
 426 }
 427
 428 static void backup_job_completed(void *opaque, int ret)
 429 {
 430     BlockDriverState *bs = opaque;
 431     BDRVReplicationState *s = bs->opaque;
 432
 433     if (s->stage != BLOCK_REPLICATION_FAILOVER) {
 434         /* The backup job is cancelled unexpectedly */
 435         s->error = -EIO;
 436     }
 437
 438     backup_job_cleanup(bs);
 439 }
 440
 441 static bool check_top_bs(BlockDriverState *top_bs, BlockDriverState *bs)
 442 {
 443     BdrvChild *child;
 444
 445     /* The bs itself is the top_bs */
 446     if (top_bs == bs) {
 447         return true;
 448     }
 449
 450     /* Iterate over top_bs's children */
 451     QLIST_FOREACH(child, &top_bs->children, next) {
 452         if (child->bs == bs || check_top_bs(child->bs, bs)) {
 453             return true;
 454         }
 455     }
 456
 457     return false;
 458 }
 459
 460 static void replication_start(ReplicationState *rs, ReplicationMode mode,
 461                               Error **errp)
 462 {
 463     BlockDriverState *bs = rs->opaque;
 464     BDRVReplicationState *s;
 465     BlockDriverState *top_bs;
 466     int64_t active_length, hidden_length, disk_length;
 467     AioContext *aio_context;
 468     Error *local_err = NULL;
 469     BlockJob *job;
 470
 471     aio_context = bdrv_get_aio_context(bs);
 472     aio_context_acquire(aio_context);
 473     s = bs->opaque;
 474
 475     if (s->stage != BLOCK_REPLICATION_NONE) {
 476         error_setg(errp, "Block replication is running or done");
 477         aio_context_release(aio_context);
 478         return;
 479     }
 480
 481     if (s->mode != mode) {
 482         error_setg(errp, "The parameter mode's value is invalid, needs %d,"
 483                    " but got %d", s->mode, mode);
 484         aio_context_release(aio_context);
 485         return;
 486     }
 487
 488     switch (s->mode) {
 489     case REPLICATION_MODE_PRIMARY:
 490         break;
 491     case REPLICATION_MODE_SECONDARY:
 492         s->active_disk = bs->file;
 493         if (!s->active_disk || !s->active_disk->bs ||
 494                                     !s->active_disk->bs->backing) {
 495             error_setg(errp, "Active disk doesn't have backing file");
 496             aio_context_release(aio_context);
 497             return;
 498         }
 499
 500         s->hidden_disk = s->active_disk->bs->backing;
 501         if (!s->hidden_disk->bs || !s->hidden_disk->bs->backing) {
 502             error_setg(errp, "Hidden disk doesn't have backing file");
 503             aio_context_release(aio_context);
 504             return;
 505         }
 506
 507         s->secondary_disk = s->hidden_disk->bs->backing;
 508         if (!s->secondary_disk->bs || !bdrv_has_blk(s->secondary_disk->bs)) {
 509             error_setg(errp, "The secondary disk doesn't have block backend");
 510             aio_context_release(aio_context);
 511             return;
 512         }
 513
 514         /* verify the length */
 515         active_length = bdrv_getlength(s->active_disk->bs);
 516         hidden_length = bdrv_getlength(s->hidden_disk->bs);
 517         disk_length = bdrv_getlength(s->secondary_disk->bs);
 518         if (active_length < 0 || hidden_length < 0 || disk_length < 0 ||
 519             active_length != hidden_length || hidden_length != disk_length) {
 520             error_setg(errp, "Active disk, hidden disk, secondary disk's length"
 521                        " are not the same");
 522             aio_context_release(aio_context);
 523             return;
 524         }
 525
 526         /* Must be true, or the bdrv_getlength() calls would have failed */
 527         assert(s->active_disk->bs->drv && s->hidden_disk->bs->drv);
 528
 529         if (!s->active_disk->bs->drv->bdrv_make_empty ||
 530             !s->hidden_disk->bs->drv->bdrv_make_empty) {
 531             error_setg(errp,
 532                        "Active disk or hidden disk doesn't support make_empty");
 533             aio_context_release(aio_context);
 534             return;
 535         }
 536
 537         /* reopen the backing file in r/w mode */
 538         reopen_backing_file(bs, true, &local_err);
 539         if (local_err) {
 540             error_propagate(errp, local_err);
 541             aio_context_release(aio_context);
 542             return;
 543         }
 544
 545         /* start backup job now */
 546         error_setg(&s->blocker,
 547                    "Block device is in use by internal backup job");
 548
 549         top_bs = bdrv_lookup_bs(s->top_id, s->top_id, NULL);
 550         if (!top_bs || !bdrv_is_root_node(top_bs) ||
 551             !check_top_bs(top_bs, bs)) {
 552             error_setg(errp, "No top_bs or it is invalid");
 553             reopen_backing_file(bs, false, NULL);
 554             aio_context_release(aio_context);
 555             return;
 556         }
 557         bdrv_op_block_all(top_bs, s->blocker);
 558         bdrv_op_unblock(top_bs, BLOCK_OP_TYPE_DATAPLANE, s->blocker);
 559
 560         job = backup_job_create(NULL, s->secondary_disk->bs, s->hidden_disk->bs,
 561                                 0, MIRROR_SYNC_MODE_NONE, NULL, false,
 562                                 BLOCKDEV_ON_ERROR_REPORT,
 563                                 BLOCKDEV_ON_ERROR_REPORT, BLOCK_JOB_INTERNAL,
 564                                 backup_job_completed, bs, NULL, &local_err);
 565         if (local_err) {
 566             error_propagate(errp, local_err);
 567             backup_job_cleanup(bs);
 568             aio_context_release(aio_context);
 569             return;
 570         }
 571         block_job_start(job);
 572         break;
 573     default:
 574         aio_context_release(aio_context);
 575         abort();
 576     }
 577
 578     s->stage = BLOCK_REPLICATION_RUNNING;
 579
 580     if (s->mode == REPLICATION_MODE_SECONDARY) {
 581         secondary_do_checkpoint(s, errp);
 582     }
 583
 584     s->error = 0;
 585     aio_context_release(aio_context);
 586 }
 587
 588 static void replication_do_checkpoint(ReplicationState *rs, Error **errp)
 589 {
 590     BlockDriverState *bs = rs->opaque;
 591     BDRVReplicationState *s;
 592     AioContext *aio_context;
 593
 594     aio_context = bdrv_get_aio_context(bs);
 595     aio_context_acquire(aio_context);
 596     s = bs->opaque;
 597
 598     if (s->mode == REPLICATION_MODE_SECONDARY) {
 599         secondary_do_checkpoint(s, errp);
 600     }
 601     aio_context_release(aio_context);
 602 }
 603
 604 static void replication_get_error(ReplicationState *rs, Error **errp)
 605 {
 606     BlockDriverState *bs = rs->opaque;
 607     BDRVReplicationState *s;
 608     AioContext *aio_context;
 609
 610     aio_context = bdrv_get_aio_context(bs);
 611     aio_context_acquire(aio_context);
 612     s = bs->opaque;
 613
 614     if (s->stage != BLOCK_REPLICATION_RUNNING) {
 615         error_setg(errp, "Block replication is not running");
 616         aio_context_release(aio_context);
 617         return;
 618     }
 619
 620     if (s->error) {
 621         error_setg(errp, "I/O error occurred");
 622         aio_context_release(aio_context);
 623         return;
 624     }
 625     aio_context_release(aio_context);
 626 }
 627
 628 static void replication_done(void *opaque, int ret)
 629 {
 630     BlockDriverState *bs = opaque;
 631     BDRVReplicationState *s = bs->opaque;
 632
 633     if (ret == 0) {
 634         s->stage = BLOCK_REPLICATION_DONE;
 635
 636         /* refresh top bs's filename */
 637         bdrv_refresh_filename(bs);
 638         s->active_disk = NULL;
 639         s->secondary_disk = NULL;
 640         s->hidden_disk = NULL;
 641         s->error = 0;
 642     } else {
 643         s->stage = BLOCK_REPLICATION_FAILOVER_FAILED;
 644         s->error = -EIO;
 645     }
 646 }
 647
 648 static void replication_stop(ReplicationState *rs, bool failover, Error **errp)
 649 {
 650     BlockDriverState *bs = rs->opaque;
 651     BDRVReplicationState *s;
 652     AioContext *aio_context;
 653
 654     aio_context = bdrv_get_aio_context(bs);
 655     aio_context_acquire(aio_context);
 656     s = bs->opaque;
 657
 658     if (s->stage != BLOCK_REPLICATION_RUNNING) {
 659         error_setg(errp, "Block replication is not running");
 660         aio_context_release(aio_context);
 661         return;
 662     }
 663
 664     switch (s->mode) {
 665     case REPLICATION_MODE_PRIMARY:
 666         s->stage = BLOCK_REPLICATION_DONE;
 667         s->error = 0;
 668         break;
 669     case REPLICATION_MODE_SECONDARY:
 670         /*
 671          * This BDS will be closed, and the job should be completed
 672          * before the BDS is closed, because we will access hidden
 673          * disk, secondary disk in backup_job_completed().
 674          */
 675         if (s->secondary_disk->bs->job) {
 676             block_job_cancel_sync(s->secondary_disk->bs->job);
 677         }
 678
 679         if (!failover) {
 680             secondary_do_checkpoint(s, errp);
 681             s->stage = BLOCK_REPLICATION_DONE;
 682             aio_context_release(aio_context);
 683             return;
 684         }
 685
 686         s->stage = BLOCK_REPLICATION_FAILOVER;
 687         commit_active_start(NULL, s->active_disk->bs, s->secondary_disk->bs,
 688                             BLOCK_JOB_INTERNAL, 0, BLOCKDEV_ON_ERROR_REPORT,
 689                             NULL, replication_done, bs, true, errp);
 690         break;
 691     default:
 692         aio_context_release(aio_context);
 693         abort();
 694     }
 695     aio_context_release(aio_context);
 696 }
 697
 698 BlockDriver bdrv_replication = {
 699     .format_name                = "replication",
 700     .protocol_name              = "replication",
 701     .instance_size              = sizeof(BDRVReplicationState),
 702
 703     .bdrv_open                  = replication_open,
 704     .bdrv_close                 = replication_close,
 705     .bdrv_child_perm            = replication_child_perm,
 706
 707     .bdrv_getlength             = replication_getlength,
 708     .bdrv_co_readv              = replication_co_readv,
 709     .bdrv_co_writev             = replication_co_writev,
 710
 711     .is_filter                  = true,
 712     .bdrv_recurse_is_first_non_filter = replication_recurse_is_first_non_filter,
 713
 714     .has_variable_length        = true,
 715 };
 716
 717 static void bdrv_replication_init(void)
 718 {
 719     bdrv_register(&bdrv_replication);
 720 }
 721
 722 block_init(bdrv_replication_init);