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 <wency@cn.fujitsu.com>
  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/module.h"
  17 #include "qemu/option.h"
  18 #include "block/nbd.h"
  19 #include "block/blockjob.h"
  20 #include "block/block_int.h"
  21 #include "block/block_backup.h"
  22 #include "sysemu/block-backend.h"
  23 #include "qapi/error.h"
  24 #include "qapi/qmp/qdict.h"
  25 #include "replication.h"
  26
  27 typedef enum {
  28     BLOCK_REPLICATION_NONE,             /* block replication is not started */
  29     BLOCK_REPLICATION_RUNNING,          /* block replication is running */
  30     BLOCK_REPLICATION_FAILOVER,         /* failover is running in background */
  31     BLOCK_REPLICATION_FAILOVER_FAILED,  /* failover failed */
  32     BLOCK_REPLICATION_DONE,             /* block replication is done */
  33 } ReplicationStage;
  34
  35 typedef struct BDRVReplicationState {
  36     ReplicationMode mode;
  37     ReplicationStage stage;
  38     BdrvChild *active_disk;
  39     BlockJob *commit_job;
  40     BdrvChild *hidden_disk;
  41     BdrvChild *secondary_disk;
  42     BlockJob *backup_job;
  43     char *top_id;
  44     ReplicationState *rs;
  45     Error *blocker;
  46     bool orig_hidden_read_only;
  47     bool orig_secondary_read_only;
  48     int error;
  49 } BDRVReplicationState;
  50
  51 static void replication_start(ReplicationState *rs, ReplicationMode mode,
  52                               Error **errp);
  53 static void replication_do_checkpoint(ReplicationState *rs, Error **errp);
  54 static void replication_get_error(ReplicationState *rs, Error **errp);
  55 static void replication_stop(ReplicationState *rs, bool failover,
  56                              Error **errp);
  57
  58 #define REPLICATION_MODE        "mode"
  59 #define REPLICATION_TOP_ID      "top-id"
  60 static QemuOptsList replication_runtime_opts = {
  61     .name = "replication",
  62     .head = QTAILQ_HEAD_INITIALIZER(replication_runtime_opts.head),
  63     .desc = {
  64         {
  65             .name = REPLICATION_MODE,
  66             .type = QEMU_OPT_STRING,
  67         },
  68         {
  69             .name = REPLICATION_TOP_ID,
  70             .type = QEMU_OPT_STRING,
  71         },
  72         { /* end of list */ }
  73     },
  74 };
  75
  76 static ReplicationOps replication_ops = {
  77     .start = replication_start,
  78     .checkpoint = replication_do_checkpoint,
  79     .get_error = replication_get_error,
  80     .stop = replication_stop,
  81 };
  82
  83 static int replication_open(BlockDriverState *bs, QDict *options,
  84                             int flags, Error **errp)
  85 {
  86     int ret;
  87     BDRVReplicationState *s = bs->opaque;
  88     Error *local_err = NULL;
  89     QemuOpts *opts = NULL;
  90     const char *mode;
  91     const char *top_id;
  92
  93     bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
  94                                false, errp);
  95     if (!bs->file) {
  96         return -EINVAL;
  97     }
  98
  99     ret = -EINVAL;
 100     opts = qemu_opts_create(&replication_runtime_opts, NULL, 0, &error_abort);
 101     qemu_opts_absorb_qdict(opts, options, &local_err);
 102     if (local_err) {
 103         goto fail;
 104     }
 105
 106     mode = qemu_opt_get(opts, REPLICATION_MODE);
 107     if (!mode) {
 108         error_setg(&local_err, "Missing the option mode");
 109         goto fail;
 110     }
 111
 112     if (!strcmp(mode, "primary")) {
 113         s->mode = REPLICATION_MODE_PRIMARY;
 114         top_id = qemu_opt_get(opts, REPLICATION_TOP_ID);
 115         if (top_id) {
 116             error_setg(&local_err, "The primary side does not support option top-id");
 117             goto fail;
 118         }
 119     } else if (!strcmp(mode, "secondary")) {
 120         s->mode = REPLICATION_MODE_SECONDARY;
 121         top_id = qemu_opt_get(opts, REPLICATION_TOP_ID);
 122         s->top_id = g_strdup(top_id);
 123         if (!s->top_id) {
 124             error_setg(&local_err, "Missing the option top-id");
 125             goto fail;
 126         }
 127     } else {
 128         error_setg(&local_err,
 129                    "The option mode's value should be primary or secondary");
 130         goto fail;
 131     }
 132
 133     s->rs = replication_new(bs, &replication_ops);
 134
 135     ret = 0;
 136
 137 fail:
 138     qemu_opts_del(opts);
 139     error_propagate(errp, local_err);
 140
 141     return ret;
 142 }
 143
 144 static void replication_close(BlockDriverState *bs)
 145 {
 146     BDRVReplicationState *s = bs->opaque;
 147
 148     if (s->stage == BLOCK_REPLICATION_RUNNING) {
 149         replication_stop(s->rs, false, NULL);
 150     }
 151     if (s->stage == BLOCK_REPLICATION_FAILOVER) {
 152         job_cancel_sync(&s->commit_job->job);
 153     }
 154
 155     if (s->mode == REPLICATION_MODE_SECONDARY) {
 156         g_free(s->top_id);
 157     }
 158
 159     replication_remove(s->rs);
 160 }
 161
 162 static void replication_child_perm(BlockDriverState *bs, BdrvChild *c,
 163                                    const BdrvChildRole *role,
 164                                    BlockReopenQueue *reopen_queue,
 165                                    uint64_t perm, uint64_t shared,
 166                                    uint64_t *nperm, uint64_t *nshared)
 167 {
 168     *nperm = BLK_PERM_CONSISTENT_READ;
 169     if ((bs->open_flags & (BDRV_O_INACTIVE | BDRV_O_RDWR)) == BDRV_O_RDWR) {
 170         *nperm |= BLK_PERM_WRITE;
 171     }
 172     *nshared = BLK_PERM_CONSISTENT_READ \
 173                | BLK_PERM_WRITE \
 174                | BLK_PERM_WRITE_UNCHANGED;
 175     return;
 176 }
 177
 178 static int64_t replication_getlength(BlockDriverState *bs)
 179 {
 180     return bdrv_getlength(bs->file->bs);
 181 }
 182
 183 static int replication_get_io_status(BDRVReplicationState *s)
 184 {
 185     switch (s->stage) {
 186     case BLOCK_REPLICATION_NONE:
 187         return -EIO;
 188     case BLOCK_REPLICATION_RUNNING:
 189         return 0;
 190     case BLOCK_REPLICATION_FAILOVER:
 191         return s->mode == REPLICATION_MODE_PRIMARY ? -EIO : 0;
 192     case BLOCK_REPLICATION_FAILOVER_FAILED:
 193         return s->mode == REPLICATION_MODE_PRIMARY ? -EIO : 1;
 194     case BLOCK_REPLICATION_DONE:
 195         /*
 196          * active commit job completes, and active disk and secondary_disk
 197          * is swapped, so we can operate bs->file directly
 198          */
 199         return s->mode == REPLICATION_MODE_PRIMARY ? -EIO : 0;
 200     default:
 201         abort();
 202     }
 203 }
 204
 205 static int replication_return_value(BDRVReplicationState *s, int ret)
 206 {
 207     if (s->mode == REPLICATION_MODE_SECONDARY) {
 208         return ret;
 209     }
 210
 211     if (ret < 0) {
 212         s->error = ret;
 213         ret = 0;
 214     }
 215
 216     return ret;
 217 }
 218
 219 static coroutine_fn int replication_co_readv(BlockDriverState *bs,
 220                                              int64_t sector_num,
 221                                              int remaining_sectors,
 222                                              QEMUIOVector *qiov)
 223 {
 224     BDRVReplicationState *s = bs->opaque;
 225     int ret;
 226
 227     if (s->mode == REPLICATION_MODE_PRIMARY) {
 228         /* We only use it to forward primary write requests */
 229         return -EIO;
 230     }
 231
 232     ret = replication_get_io_status(s);
 233     if (ret < 0) {
 234         return ret;
 235     }
 236
 237     ret = bdrv_co_preadv(bs->file, sector_num * BDRV_SECTOR_SIZE,
 238                          remaining_sectors * BDRV_SECTOR_SIZE, qiov, 0);
 239
 240     return replication_return_value(s, ret);
 241 }
 242
 243 static coroutine_fn int replication_co_writev(BlockDriverState *bs,
 244                                               int64_t sector_num,
 245                                               int remaining_sectors,
 246                                               QEMUIOVector *qiov,
 247                                               int flags)
 248 {
 249     BDRVReplicationState *s = bs->opaque;
 250     QEMUIOVector hd_qiov;
 251     uint64_t bytes_done = 0;
 252     BdrvChild *top = bs->file;
 253     BdrvChild *base = s->secondary_disk;
 254     BdrvChild *target;
 255     int ret;
 256     int64_t n;
 257
 258     assert(!flags);
 259     ret = replication_get_io_status(s);
 260     if (ret < 0) {
 261         goto out;
 262     }
 263
 264     if (ret == 0) {
 265         ret = bdrv_co_pwritev(top, sector_num * BDRV_SECTOR_SIZE,
 266                               remaining_sectors * BDRV_SECTOR_SIZE, qiov, 0);
 267         return replication_return_value(s, ret);
 268     }
 269
 270     /*
 271      * Failover failed, only write to active disk if the sectors
 272      * have already been allocated in active disk/hidden disk.
 273      */
 274     qemu_iovec_init(&hd_qiov, qiov->niov);
 275     while (remaining_sectors > 0) {
 276         int64_t count;
 277
 278         ret = bdrv_is_allocated_above(top->bs, base->bs, false,
 279                                       sector_num * BDRV_SECTOR_SIZE,
 280                                       remaining_sectors * BDRV_SECTOR_SIZE,
 281                                       &count);
 282         if (ret < 0) {
 283             goto out1;
 284         }
 285
 286         assert(QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE));
 287         n = count >> BDRV_SECTOR_BITS;
 288         qemu_iovec_reset(&hd_qiov);
 289         qemu_iovec_concat(&hd_qiov, qiov, bytes_done, count);
 290
 291         target = ret ? top : base;
 292         ret = bdrv_co_pwritev(target, sector_num * BDRV_SECTOR_SIZE,
 293                               n * BDRV_SECTOR_SIZE, &hd_qiov, 0);
 294         if (ret < 0) {
 295             goto out1;
 296         }
 297
 298         remaining_sectors -= n;
 299         sector_num += n;
 300         bytes_done += count;
 301     }
 302
 303 out1:
 304     qemu_iovec_destroy(&hd_qiov);
 305 out:
 306     return ret;
 307 }
 308
 309 static void secondary_do_checkpoint(BDRVReplicationState *s, Error **errp)
 310 {
 311     Error *local_err = NULL;
 312     int ret;
 313
 314     if (!s->backup_job) {
 315         error_setg(errp, "Backup job was cancelled unexpectedly");
 316         return;
 317     }
 318
 319     backup_do_checkpoint(s->backup_job, &local_err);
 320     if (local_err) {
 321         error_propagate(errp, local_err);
 322         return;
 323     }
 324
 325     if (!s->active_disk->bs->drv) {
 326         error_setg(errp, "Active disk %s is ejected",
 327                    s->active_disk->bs->node_name);
 328         return;
 329     }
 330
 331     ret = s->active_disk->bs->drv->bdrv_make_empty(s->active_disk->bs);
 332     if (ret < 0) {
 333         error_setg(errp, "Cannot make active disk empty");
 334         return;
 335     }
 336
 337     if (!s->hidden_disk->bs->drv) {
 338         error_setg(errp, "Hidden disk %s is ejected",
 339                    s->hidden_disk->bs->node_name);
 340         return;
 341     }
 342
 343     ret = s->hidden_disk->bs->drv->bdrv_make_empty(s->hidden_disk->bs);
 344     if (ret < 0) {
 345         error_setg(errp, "Cannot make hidden disk empty");
 346         return;
 347     }
 348 }
 349
 350 /* This function is supposed to be called twice:
 351  * first with writable = true, then with writable = false.
 352  * The first call puts s->hidden_disk and s->secondary_disk in
 353  * r/w mode, and the second puts them back in their original state.
 354  */
 355 static void reopen_backing_file(BlockDriverState *bs, bool writable,
 356                                 Error **errp)
 357 {
 358     BDRVReplicationState *s = bs->opaque;
 359     BlockReopenQueue *reopen_queue = NULL;
 360     Error *local_err = NULL;
 361
 362     if (writable) {
 363         s->orig_hidden_read_only = bdrv_is_read_only(s->hidden_disk->bs);
 364         s->orig_secondary_read_only = bdrv_is_read_only(s->secondary_disk->bs);
 365     }
 366
 367     bdrv_subtree_drained_begin(s->hidden_disk->bs);
 368     bdrv_subtree_drained_begin(s->secondary_disk->bs);
 369
 370     if (s->orig_hidden_read_only) {
 371         QDict *opts = qdict_new();
 372         qdict_put_bool(opts, BDRV_OPT_READ_ONLY, !writable);
 373         reopen_queue = bdrv_reopen_queue(reopen_queue, s->hidden_disk->bs,
 374                                          opts, true);
 375     }
 376
 377     if (s->orig_secondary_read_only) {
 378         QDict *opts = qdict_new();
 379         qdict_put_bool(opts, BDRV_OPT_READ_ONLY, !writable);
 380         reopen_queue = bdrv_reopen_queue(reopen_queue, s->secondary_disk->bs,
 381                                          opts, true);
 382     }
 383
 384     if (reopen_queue) {
 385         bdrv_reopen_multiple(reopen_queue, &local_err);
 386         error_propagate(errp, local_err);
 387     }
 388
 389     bdrv_subtree_drained_end(s->hidden_disk->bs);
 390     bdrv_subtree_drained_end(s->secondary_disk->bs);
 391 }
 392
 393 static void backup_job_cleanup(BlockDriverState *bs)
 394 {
 395     BDRVReplicationState *s = bs->opaque;
 396     BlockDriverState *top_bs;
 397
 398     top_bs = bdrv_lookup_bs(s->top_id, s->top_id, NULL);
 399     if (!top_bs) {
 400         return;
 401     }
 402     bdrv_op_unblock_all(top_bs, s->blocker);
 403     error_free(s->blocker);
 404     reopen_backing_file(bs, false, NULL);
 405 }
 406
 407 static void backup_job_completed(void *opaque, int ret)
 408 {
 409     BlockDriverState *bs = opaque;
 410     BDRVReplicationState *s = bs->opaque;
 411
 412     if (s->stage != BLOCK_REPLICATION_FAILOVER) {
 413         /* The backup job is cancelled unexpectedly */
 414         s->error = -EIO;
 415     }
 416
 417     backup_job_cleanup(bs);
 418 }
 419
 420 static bool check_top_bs(BlockDriverState *top_bs, BlockDriverState *bs)
 421 {
 422     BdrvChild *child;
 423
 424     /* The bs itself is the top_bs */
 425     if (top_bs == bs) {
 426         return true;
 427     }
 428
 429     /* Iterate over top_bs's children */
 430     QLIST_FOREACH(child, &top_bs->children, next) {
 431         if (child->bs == bs || check_top_bs(child->bs, bs)) {
 432             return true;
 433         }
 434     }
 435
 436     return false;
 437 }
 438
 439 static void replication_start(ReplicationState *rs, ReplicationMode mode,
 440                               Error **errp)
 441 {
 442     BlockDriverState *bs = rs->opaque;
 443     BDRVReplicationState *s;
 444     BlockDriverState *top_bs;
 445     int64_t active_length, hidden_length, disk_length;
 446     AioContext *aio_context;
 447     Error *local_err = NULL;
 448
 449     aio_context = bdrv_get_aio_context(bs);
 450     aio_context_acquire(aio_context);
 451     s = bs->opaque;
 452
 453     if (s->stage == BLOCK_REPLICATION_DONE ||
 454         s->stage == BLOCK_REPLICATION_FAILOVER) {
 455         /*
 456          * This case happens when a secondary is promoted to primary.
 457          * Ignore the request because the secondary side of replication
 458          * doesn't have to do anything anymore.
 459          */
 460         aio_context_release(aio_context);
 461         return;
 462     }
 463
 464     if (s->stage != BLOCK_REPLICATION_NONE) {
 465         error_setg(errp, "Block replication is running or done");
 466         aio_context_release(aio_context);
 467         return;
 468     }
 469
 470     if (s->mode != mode) {
 471         error_setg(errp, "The parameter mode's value is invalid, needs %d,"
 472                    " but got %d", s->mode, mode);
 473         aio_context_release(aio_context);
 474         return;
 475     }
 476
 477     switch (s->mode) {
 478     case REPLICATION_MODE_PRIMARY:
 479         break;
 480     case REPLICATION_MODE_SECONDARY:
 481         s->active_disk = bs->file;
 482         if (!s->active_disk || !s->active_disk->bs ||
 483                                     !s->active_disk->bs->backing) {
 484             error_setg(errp, "Active disk doesn't have backing file");
 485             aio_context_release(aio_context);
 486             return;
 487         }
 488
 489         s->hidden_disk = s->active_disk->bs->backing;
 490         if (!s->hidden_disk->bs || !s->hidden_disk->bs->backing) {
 491             error_setg(errp, "Hidden disk doesn't have backing file");
 492             aio_context_release(aio_context);
 493             return;
 494         }
 495
 496         s->secondary_disk = s->hidden_disk->bs->backing;
 497         if (!s->secondary_disk->bs || !bdrv_has_blk(s->secondary_disk->bs)) {
 498             error_setg(errp, "The secondary disk doesn't have block backend");
 499             aio_context_release(aio_context);
 500             return;
 501         }
 502
 503         /* verify the length */
 504         active_length = bdrv_getlength(s->active_disk->bs);
 505         hidden_length = bdrv_getlength(s->hidden_disk->bs);
 506         disk_length = bdrv_getlength(s->secondary_disk->bs);
 507         if (active_length < 0 || hidden_length < 0 || disk_length < 0 ||
 508             active_length != hidden_length || hidden_length != disk_length) {
 509             error_setg(errp, "Active disk, hidden disk, secondary disk's length"
 510                        " are not the same");
 511             aio_context_release(aio_context);
 512             return;
 513         }
 514
 515         /* Must be true, or the bdrv_getlength() calls would have failed */
 516         assert(s->active_disk->bs->drv && s->hidden_disk->bs->drv);
 517
 518         if (!s->active_disk->bs->drv->bdrv_make_empty ||
 519             !s->hidden_disk->bs->drv->bdrv_make_empty) {
 520             error_setg(errp,
 521                        "Active disk or hidden disk doesn't support make_empty");
 522             aio_context_release(aio_context);
 523             return;
 524         }
 525
 526         /* reopen the backing file in r/w mode */
 527         reopen_backing_file(bs, true, &local_err);
 528         if (local_err) {
 529             error_propagate(errp, local_err);
 530             aio_context_release(aio_context);
 531             return;
 532         }
 533
 534         /* start backup job now */
 535         error_setg(&s->blocker,
 536                    "Block device is in use by internal backup job");
 537
 538         top_bs = bdrv_lookup_bs(s->top_id, s->top_id, NULL);
 539         if (!top_bs || !bdrv_is_root_node(top_bs) ||
 540             !check_top_bs(top_bs, bs)) {
 541             error_setg(errp, "No top_bs or it is invalid");
 542             reopen_backing_file(bs, false, NULL);
 543             aio_context_release(aio_context);
 544             return;
 545         }
 546         bdrv_op_block_all(top_bs, s->blocker);
 547         bdrv_op_unblock(top_bs, BLOCK_OP_TYPE_DATAPLANE, s->blocker);
 548
 549         s->backup_job = backup_job_create(
 550                                 NULL, s->secondary_disk->bs, s->hidden_disk->bs,
 551                                 0, MIRROR_SYNC_MODE_NONE, NULL, 0, false, NULL,
 552                                 BLOCKDEV_ON_ERROR_REPORT,
 553                                 BLOCKDEV_ON_ERROR_REPORT, JOB_INTERNAL,
 554                                 backup_job_completed, bs, NULL, &local_err);
 555         if (local_err) {
 556             error_propagate(errp, local_err);
 557             backup_job_cleanup(bs);
 558             aio_context_release(aio_context);
 559             return;
 560         }
 561         job_start(&s->backup_job->job);
 562         break;
 563     default:
 564         aio_context_release(aio_context);
 565         abort();
 566     }
 567
 568     s->stage = BLOCK_REPLICATION_RUNNING;
 569
 570     if (s->mode == REPLICATION_MODE_SECONDARY) {
 571         secondary_do_checkpoint(s, errp);
 572     }
 573
 574     s->error = 0;
 575     aio_context_release(aio_context);
 576 }
 577
 578 static void replication_do_checkpoint(ReplicationState *rs, Error **errp)
 579 {
 580     BlockDriverState *bs = rs->opaque;
 581     BDRVReplicationState *s;
 582     AioContext *aio_context;
 583
 584     aio_context = bdrv_get_aio_context(bs);
 585     aio_context_acquire(aio_context);
 586     s = bs->opaque;
 587
 588     if (s->stage == BLOCK_REPLICATION_DONE ||
 589         s->stage == BLOCK_REPLICATION_FAILOVER) {
 590         /*
 591          * This case happens when a secondary was promoted to primary.
 592          * Ignore the request because the secondary side of replication
 593          * doesn't have to do anything anymore.
 594          */
 595         aio_context_release(aio_context);
 596         return;
 597     }
 598
 599     if (s->mode == REPLICATION_MODE_SECONDARY) {
 600         secondary_do_checkpoint(s, errp);
 601     }
 602     aio_context_release(aio_context);
 603 }
 604
 605 static void replication_get_error(ReplicationState *rs, Error **errp)
 606 {
 607     BlockDriverState *bs = rs->opaque;
 608     BDRVReplicationState *s;
 609     AioContext *aio_context;
 610
 611     aio_context = bdrv_get_aio_context(bs);
 612     aio_context_acquire(aio_context);
 613     s = bs->opaque;
 614
 615     if (s->stage == BLOCK_REPLICATION_NONE) {
 616         error_setg(errp, "Block replication is not running");
 617         aio_context_release(aio_context);
 618         return;
 619     }
 620
 621     if (s->error) {
 622         error_setg(errp, "I/O error occurred");
 623         aio_context_release(aio_context);
 624         return;
 625     }
 626     aio_context_release(aio_context);
 627 }
 628
 629 static void replication_done(void *opaque, int ret)
 630 {
 631     BlockDriverState *bs = opaque;
 632     BDRVReplicationState *s = bs->opaque;
 633
 634     if (ret == 0) {
 635         s->stage = BLOCK_REPLICATION_DONE;
 636
 637         s->active_disk = NULL;
 638         s->secondary_disk = NULL;
 639         s->hidden_disk = NULL;
 640         s->error = 0;
 641     } else {
 642         s->stage = BLOCK_REPLICATION_FAILOVER_FAILED;
 643         s->error = -EIO;
 644     }
 645 }
 646
 647 static void replication_stop(ReplicationState *rs, bool failover, Error **errp)
 648 {
 649     BlockDriverState *bs = rs->opaque;
 650     BDRVReplicationState *s;
 651     AioContext *aio_context;
 652
 653     aio_context = bdrv_get_aio_context(bs);
 654     aio_context_acquire(aio_context);
 655     s = bs->opaque;
 656
 657     if (s->stage == BLOCK_REPLICATION_DONE ||
 658         s->stage == BLOCK_REPLICATION_FAILOVER) {
 659         /*
 660          * This case happens when a secondary was promoted to primary.
 661          * Ignore the request because the secondary side of replication
 662          * doesn't have to do anything anymore.
 663          */
 664         aio_context_release(aio_context);
 665         return;
 666     }
 667
 668     if (s->stage != BLOCK_REPLICATION_RUNNING) {
 669         error_setg(errp, "Block replication is not running");
 670         aio_context_release(aio_context);
 671         return;
 672     }
 673
 674     switch (s->mode) {
 675     case REPLICATION_MODE_PRIMARY:
 676         s->stage = BLOCK_REPLICATION_DONE;
 677         s->error = 0;
 678         break;
 679     case REPLICATION_MODE_SECONDARY:
 680         /*
 681          * This BDS will be closed, and the job should be completed
 682          * before the BDS is closed, because we will access hidden
 683          * disk, secondary disk in backup_job_completed().
 684          */
 685         if (s->backup_job) {
 686             job_cancel_sync(&s->backup_job->job);
 687         }
 688
 689         if (!failover) {
 690             secondary_do_checkpoint(s, errp);
 691             s->stage = BLOCK_REPLICATION_DONE;
 692             aio_context_release(aio_context);
 693             return;
 694         }
 695
 696         s->stage = BLOCK_REPLICATION_FAILOVER;
 697         s->commit_job = commit_active_start(
 698                             NULL, s->active_disk->bs, s->secondary_disk->bs,
 699                             JOB_INTERNAL, 0, BLOCKDEV_ON_ERROR_REPORT,
 700                             NULL, replication_done, bs, true, errp);
 701         break;
 702     default:
 703         aio_context_release(aio_context);
 704         abort();
 705     }
 706     aio_context_release(aio_context);
 707 }
 708
 709 static const char *const replication_strong_runtime_opts[] = {
 710     REPLICATION_MODE,
 711     REPLICATION_TOP_ID,
 712
 713     NULL
 714 };
 715
 716 static BlockDriver bdrv_replication = {
 717     .format_name                = "replication",
 718     .instance_size              = sizeof(BDRVReplicationState),
 719
 720     .bdrv_open                  = replication_open,
 721     .bdrv_close                 = replication_close,
 722     .bdrv_child_perm            = replication_child_perm,
 723
 724     .bdrv_getlength             = replication_getlength,
 725     .bdrv_co_readv              = replication_co_readv,
 726     .bdrv_co_writev             = replication_co_writev,
 727
 728     .is_filter                  = true,
 729
 730     .has_variable_length        = true,
 731     .strong_runtime_opts        = replication_strong_runtime_opts,
 732 };
 733
 734 static void bdrv_replication_init(void)
 735 {
 736     bdrv_register(&bdrv_replication);
 737 }
 738
 739 block_init(bdrv_replication_init);