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     QemuOpts *opts = NULL;
  89     const char *mode;
  90     const char *top_id;
  91
  92     bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
  93                                BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
  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     if (!qemu_opts_absorb_qdict(opts, options, errp)) {
 102         goto fail;
 103     }
 104
 105     mode = qemu_opt_get(opts, REPLICATION_MODE);
 106     if (!mode) {
 107         error_setg(errp, "Missing the option mode");
 108         goto fail;
 109     }
 110
 111     if (!strcmp(mode, "primary")) {
 112         s->mode = REPLICATION_MODE_PRIMARY;
 113         top_id = qemu_opt_get(opts, REPLICATION_TOP_ID);
 114         if (top_id) {
 115             error_setg(errp,
 116                        "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(errp, "Missing the option top-id");
 125             goto fail;
 126         }
 127     } else {
 128         error_setg(errp,
 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     return ret;
 140 }
 141
 142 static void replication_close(BlockDriverState *bs)
 143 {
 144     BDRVReplicationState *s = bs->opaque;
 145     Job *commit_job;
 146
 147     if (s->stage == BLOCK_REPLICATION_RUNNING) {
 148         replication_stop(s->rs, false, NULL);
 149     }
 150     if (s->stage == BLOCK_REPLICATION_FAILOVER) {
 151         commit_job = &s->commit_job->job;
 152         assert(commit_job->aio_context == qemu_get_current_aio_context());
 153         job_cancel_sync(commit_job);
 154     }
 155
 156     if (s->mode == REPLICATION_MODE_SECONDARY) {
 157         g_free(s->top_id);
 158     }
 159
 160     replication_remove(s->rs);
 161 }
 162
 163 static void replication_child_perm(BlockDriverState *bs, BdrvChild *c,
 164                                    BdrvChildRole role,
 165                                    BlockReopenQueue *reopen_queue,
 166                                    uint64_t perm, uint64_t shared,
 167                                    uint64_t *nperm, uint64_t *nshared)
 168 {
 169     *nperm = BLK_PERM_CONSISTENT_READ;
 170     if ((bs->open_flags & (BDRV_O_INACTIVE | BDRV_O_RDWR)) == BDRV_O_RDWR) {
 171         *nperm |= BLK_PERM_WRITE;
 172     }
 173     *nshared = BLK_PERM_CONSISTENT_READ
 174                | BLK_PERM_WRITE
 175                | BLK_PERM_WRITE_UNCHANGED;
 176     return;
 177 }
 178
 179 static int64_t replication_getlength(BlockDriverState *bs)
 180 {
 181     return bdrv_getlength(bs->file->bs);
 182 }
 183
 184 static int replication_get_io_status(BDRVReplicationState *s)
 185 {
 186     switch (s->stage) {
 187     case BLOCK_REPLICATION_NONE:
 188         return -EIO;
 189     case BLOCK_REPLICATION_RUNNING:
 190         return 0;
 191     case BLOCK_REPLICATION_FAILOVER:
 192         return s->mode == REPLICATION_MODE_PRIMARY ? -EIO : 0;
 193     case BLOCK_REPLICATION_FAILOVER_FAILED:
 194         return s->mode == REPLICATION_MODE_PRIMARY ? -EIO : 1;
 195     case BLOCK_REPLICATION_DONE:
 196         /*
 197          * active commit job completes, and active disk and secondary_disk
 198          * is swapped, so we can operate bs->file directly
 199          */
 200         return s->mode == REPLICATION_MODE_PRIMARY ? -EIO : 0;
 201     default:
 202         abort();
 203     }
 204 }
 205
 206 static int replication_return_value(BDRVReplicationState *s, int ret)
 207 {
 208     if (s->mode == REPLICATION_MODE_SECONDARY) {
 209         return ret;
 210     }
 211
 212     if (ret < 0) {
 213         s->error = ret;
 214         ret = 0;
 215     }
 216
 217     return ret;
 218 }
 219
 220 static coroutine_fn int replication_co_readv(BlockDriverState *bs,
 221                                              int64_t sector_num,
 222                                              int remaining_sectors,
 223                                              QEMUIOVector *qiov)
 224 {
 225     BDRVReplicationState *s = bs->opaque;
 226     int ret;
 227
 228     if (s->mode == REPLICATION_MODE_PRIMARY) {
 229         /* We only use it to forward primary write requests */
 230         return -EIO;
 231     }
 232
 233     ret = replication_get_io_status(s);
 234     if (ret < 0) {
 235         return ret;
 236     }
 237
 238     ret = bdrv_co_preadv(bs->file, sector_num * BDRV_SECTOR_SIZE,
 239                          remaining_sectors * BDRV_SECTOR_SIZE, qiov, 0);
 240
 241     return replication_return_value(s, ret);
 242 }
 243
 244 static coroutine_fn int replication_co_writev(BlockDriverState *bs,
 245                                               int64_t sector_num,
 246                                               int remaining_sectors,
 247                                               QEMUIOVector *qiov,
 248                                               int flags)
 249 {
 250     BDRVReplicationState *s = bs->opaque;
 251     QEMUIOVector hd_qiov;
 252     uint64_t bytes_done = 0;
 253     BdrvChild *top = bs->file;
 254     BdrvChild *base = s->secondary_disk;
 255     BdrvChild *target;
 256     int ret;
 257     int64_t n;
 258
 259     assert(!flags);
 260     ret = replication_get_io_status(s);
 261     if (ret < 0) {
 262         goto out;
 263     }
 264
 265     if (ret == 0) {
 266         ret = bdrv_co_pwritev(top, sector_num * BDRV_SECTOR_SIZE,
 267                               remaining_sectors * BDRV_SECTOR_SIZE, qiov, 0);
 268         return replication_return_value(s, ret);
 269     }
 270
 271     /*
 272      * Failover failed, only write to active disk if the sectors
 273      * have already been allocated in active disk/hidden disk.
 274      */
 275     qemu_iovec_init(&hd_qiov, qiov->niov);
 276     while (remaining_sectors > 0) {
 277         int64_t count;
 278
 279         ret = bdrv_is_allocated_above(top->bs, base->bs, false,
 280                                       sector_num * BDRV_SECTOR_SIZE,
 281                                       remaining_sectors * BDRV_SECTOR_SIZE,
 282                                       &count);
 283         if (ret < 0) {
 284             goto out1;
 285         }
 286
 287         assert(QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE));
 288         n = count >> BDRV_SECTOR_BITS;
 289         qemu_iovec_reset(&hd_qiov);
 290         qemu_iovec_concat(&hd_qiov, qiov, bytes_done, count);
 291
 292         target = ret ? top : base;
 293         ret = bdrv_co_pwritev(target, sector_num * BDRV_SECTOR_SIZE,
 294                               n * BDRV_SECTOR_SIZE, &hd_qiov, 0);
 295         if (ret < 0) {
 296             goto out1;
 297         }
 298
 299         remaining_sectors -= n;
 300         sector_num += n;
 301         bytes_done += count;
 302     }
 303
 304 out1:
 305     qemu_iovec_destroy(&hd_qiov);
 306 out:
 307     return ret;
 308 }
 309
 310 static void secondary_do_checkpoint(BDRVReplicationState *s, Error **errp)
 311 {
 312     Error *local_err = NULL;
 313     int ret;
 314
 315     if (!s->backup_job) {
 316         error_setg(errp, "Backup job was cancelled unexpectedly");
 317         return;
 318     }
 319
 320     backup_do_checkpoint(s->backup_job, &local_err);
 321     if (local_err) {
 322         error_propagate(errp, local_err);
 323         return;
 324     }
 325
 326     if (!s->active_disk->bs->drv) {
 327         error_setg(errp, "Active disk %s is ejected",
 328                    s->active_disk->bs->node_name);
 329         return;
 330     }
 331
 332     ret = bdrv_make_empty(s->active_disk, errp);
 333     if (ret < 0) {
 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     BlockBackend *blk = blk_new(qemu_get_current_aio_context(),
 344                                 BLK_PERM_WRITE, BLK_PERM_ALL);
 345     blk_insert_bs(blk, s->hidden_disk->bs, &local_err);
 346     if (local_err) {
 347         error_propagate(errp, local_err);
 348         blk_unref(blk);
 349         return;
 350     }
 351
 352     ret = blk_make_empty(blk, errp);
 353     blk_unref(blk);
 354     if (ret < 0) {
 355         return;
 356     }
 357 }
 358
 359 /* This function is supposed to be called twice:
 360  * first with writable = true, then with writable = false.
 361  * The first call puts s->hidden_disk and s->secondary_disk in
 362  * r/w mode, and the second puts them back in their original state.
 363  */
 364 static void reopen_backing_file(BlockDriverState *bs, bool writable,
 365                                 Error **errp)
 366 {
 367     BDRVReplicationState *s = bs->opaque;
 368     BlockReopenQueue *reopen_queue = NULL;
 369
 370     if (writable) {
 371         s->orig_hidden_read_only = bdrv_is_read_only(s->hidden_disk->bs);
 372         s->orig_secondary_read_only = bdrv_is_read_only(s->secondary_disk->bs);
 373     }
 374
 375     bdrv_subtree_drained_begin(s->hidden_disk->bs);
 376     bdrv_subtree_drained_begin(s->secondary_disk->bs);
 377
 378     if (s->orig_hidden_read_only) {
 379         QDict *opts = qdict_new();
 380         qdict_put_bool(opts, BDRV_OPT_READ_ONLY, !writable);
 381         reopen_queue = bdrv_reopen_queue(reopen_queue, s->hidden_disk->bs,
 382                                          opts, true);
 383     }
 384
 385     if (s->orig_secondary_read_only) {
 386         QDict *opts = qdict_new();
 387         qdict_put_bool(opts, BDRV_OPT_READ_ONLY, !writable);
 388         reopen_queue = bdrv_reopen_queue(reopen_queue, s->secondary_disk->bs,
 389                                          opts, true);
 390     }
 391
 392     if (reopen_queue) {
 393         bdrv_reopen_multiple(reopen_queue, errp);
 394     }
 395
 396     bdrv_subtree_drained_end(s->hidden_disk->bs);
 397     bdrv_subtree_drained_end(s->secondary_disk->bs);
 398 }
 399
 400 static void backup_job_cleanup(BlockDriverState *bs)
 401 {
 402     BDRVReplicationState *s = bs->opaque;
 403     BlockDriverState *top_bs;
 404
 405     s->backup_job = NULL;
 406
 407     top_bs = bdrv_lookup_bs(s->top_id, s->top_id, NULL);
 408     if (!top_bs) {
 409         return;
 410     }
 411     bdrv_op_unblock_all(top_bs, s->blocker);
 412     error_free(s->blocker);
 413     reopen_backing_file(bs, false, NULL);
 414 }
 415
 416 static void backup_job_completed(void *opaque, int ret)
 417 {
 418     BlockDriverState *bs = opaque;
 419     BDRVReplicationState *s = bs->opaque;
 420
 421     if (s->stage != BLOCK_REPLICATION_FAILOVER) {
 422         /* The backup job is cancelled unexpectedly */
 423         s->error = -EIO;
 424     }
 425
 426     backup_job_cleanup(bs);
 427 }
 428
 429 static bool check_top_bs(BlockDriverState *top_bs, BlockDriverState *bs)
 430 {
 431     BdrvChild *child;
 432
 433     /* The bs itself is the top_bs */
 434     if (top_bs == bs) {
 435         return true;
 436     }
 437
 438     /* Iterate over top_bs's children */
 439     QLIST_FOREACH(child, &top_bs->children, next) {
 440         if (child->bs == bs || check_top_bs(child->bs, bs)) {
 441             return true;
 442         }
 443     }
 444
 445     return false;
 446 }
 447
 448 static void replication_start(ReplicationState *rs, ReplicationMode mode,
 449                               Error **errp)
 450 {
 451     BlockDriverState *bs = rs->opaque;
 452     BDRVReplicationState *s;
 453     BlockDriverState *top_bs;
 454     int64_t active_length, hidden_length, disk_length;
 455     AioContext *aio_context;
 456     Error *local_err = NULL;
 457     BackupPerf perf = { .use_copy_range = true, .max_workers = 1 };
 458
 459     aio_context = bdrv_get_aio_context(bs);
 460     aio_context_acquire(aio_context);
 461     s = bs->opaque;
 462
 463     if (s->stage == BLOCK_REPLICATION_DONE ||
 464         s->stage == BLOCK_REPLICATION_FAILOVER) {
 465         /*
 466          * This case happens when a secondary is promoted to primary.
 467          * Ignore the request because the secondary side of replication
 468          * doesn't have to do anything anymore.
 469          */
 470         aio_context_release(aio_context);
 471         return;
 472     }
 473
 474     if (s->stage != BLOCK_REPLICATION_NONE) {
 475         error_setg(errp, "Block replication is running or done");
 476         aio_context_release(aio_context);
 477         return;
 478     }
 479
 480     if (s->mode != mode) {
 481         error_setg(errp, "The parameter mode's value is invalid, needs %d,"
 482                    " but got %d", s->mode, mode);
 483         aio_context_release(aio_context);
 484         return;
 485     }
 486
 487     switch (s->mode) {
 488     case REPLICATION_MODE_PRIMARY:
 489         break;
 490     case REPLICATION_MODE_SECONDARY:
 491         s->active_disk = bs->file;
 492         if (!s->active_disk || !s->active_disk->bs ||
 493                                     !s->active_disk->bs->backing) {
 494             error_setg(errp, "Active disk doesn't have backing file");
 495             aio_context_release(aio_context);
 496             return;
 497         }
 498
 499         s->hidden_disk = s->active_disk->bs->backing;
 500         if (!s->hidden_disk->bs || !s->hidden_disk->bs->backing) {
 501             error_setg(errp, "Hidden disk doesn't have backing file");
 502             aio_context_release(aio_context);
 503             return;
 504         }
 505
 506         s->secondary_disk = s->hidden_disk->bs->backing;
 507         if (!s->secondary_disk->bs || !bdrv_has_blk(s->secondary_disk->bs)) {
 508             error_setg(errp, "The secondary disk doesn't have block backend");
 509             aio_context_release(aio_context);
 510             return;
 511         }
 512
 513         /* verify the length */
 514         active_length = bdrv_getlength(s->active_disk->bs);
 515         hidden_length = bdrv_getlength(s->hidden_disk->bs);
 516         disk_length = bdrv_getlength(s->secondary_disk->bs);
 517         if (active_length < 0 || hidden_length < 0 || disk_length < 0 ||
 518             active_length != hidden_length || hidden_length != disk_length) {
 519             error_setg(errp, "Active disk, hidden disk, secondary disk's length"
 520                        " are not the same");
 521             aio_context_release(aio_context);
 522             return;
 523         }
 524
 525         /* Must be true, or the bdrv_getlength() calls would have failed */
 526         assert(s->active_disk->bs->drv && s->hidden_disk->bs->drv);
 527
 528         if (!s->active_disk->bs->drv->bdrv_make_empty ||
 529             !s->hidden_disk->bs->drv->bdrv_make_empty) {
 530             error_setg(errp,
 531                        "Active disk or hidden disk doesn't support make_empty");
 532             aio_context_release(aio_context);
 533             return;
 534         }
 535
 536         /* reopen the backing file in r/w mode */
 537         reopen_backing_file(bs, true, &local_err);
 538         if (local_err) {
 539             error_propagate(errp, local_err);
 540             aio_context_release(aio_context);
 541             return;
 542         }
 543
 544         /* start backup job now */
 545         error_setg(&s->blocker,
 546                    "Block device is in use by internal backup job");
 547
 548         top_bs = bdrv_lookup_bs(s->top_id, s->top_id, NULL);
 549         if (!top_bs || !bdrv_is_root_node(top_bs) ||
 550             !check_top_bs(top_bs, bs)) {
 551             error_setg(errp, "No top_bs or it is invalid");
 552             reopen_backing_file(bs, false, NULL);
 553             aio_context_release(aio_context);
 554             return;
 555         }
 556         bdrv_op_block_all(top_bs, s->blocker);
 557         bdrv_op_unblock(top_bs, BLOCK_OP_TYPE_DATAPLANE, s->blocker);
 558
 559         s->backup_job = backup_job_create(
 560                                 NULL, s->secondary_disk->bs, s->hidden_disk->bs,
 561                                 0, MIRROR_SYNC_MODE_NONE, NULL, 0, false, NULL,
 562                                 &perf,
 563                                 BLOCKDEV_ON_ERROR_REPORT,
 564                                 BLOCKDEV_ON_ERROR_REPORT, JOB_INTERNAL,
 565                                 backup_job_completed, bs, NULL, &local_err);
 566         if (local_err) {
 567             error_propagate(errp, local_err);
 568             backup_job_cleanup(bs);
 569             aio_context_release(aio_context);
 570             return;
 571         }
 572         job_start(&s->backup_job->job);
 573         break;
 574     default:
 575         aio_context_release(aio_context);
 576         abort();
 577     }
 578
 579     s->stage = BLOCK_REPLICATION_RUNNING;
 580
 581     if (s->mode == REPLICATION_MODE_SECONDARY) {
 582         secondary_do_checkpoint(s, errp);
 583     }
 584
 585     s->error = 0;
 586     aio_context_release(aio_context);
 587 }
 588
 589 static void replication_do_checkpoint(ReplicationState *rs, Error **errp)
 590 {
 591     BlockDriverState *bs = rs->opaque;
 592     BDRVReplicationState *s;
 593     AioContext *aio_context;
 594
 595     aio_context = bdrv_get_aio_context(bs);
 596     aio_context_acquire(aio_context);
 597     s = bs->opaque;
 598
 599     if (s->stage == BLOCK_REPLICATION_DONE ||
 600         s->stage == BLOCK_REPLICATION_FAILOVER) {
 601         /*
 602          * This case happens when a secondary was promoted to primary.
 603          * Ignore the request because the secondary side of replication
 604          * doesn't have to do anything anymore.
 605          */
 606         aio_context_release(aio_context);
 607         return;
 608     }
 609
 610     if (s->mode == REPLICATION_MODE_SECONDARY) {
 611         secondary_do_checkpoint(s, errp);
 612     }
 613     aio_context_release(aio_context);
 614 }
 615
 616 static void replication_get_error(ReplicationState *rs, Error **errp)
 617 {
 618     BlockDriverState *bs = rs->opaque;
 619     BDRVReplicationState *s;
 620     AioContext *aio_context;
 621
 622     aio_context = bdrv_get_aio_context(bs);
 623     aio_context_acquire(aio_context);
 624     s = bs->opaque;
 625
 626     if (s->stage == BLOCK_REPLICATION_NONE) {
 627         error_setg(errp, "Block replication is not running");
 628         aio_context_release(aio_context);
 629         return;
 630     }
 631
 632     if (s->error) {
 633         error_setg(errp, "I/O error occurred");
 634         aio_context_release(aio_context);
 635         return;
 636     }
 637     aio_context_release(aio_context);
 638 }
 639
 640 static void replication_done(void *opaque, int ret)
 641 {
 642     BlockDriverState *bs = opaque;
 643     BDRVReplicationState *s = bs->opaque;
 644
 645     if (ret == 0) {
 646         s->stage = BLOCK_REPLICATION_DONE;
 647
 648         s->active_disk = NULL;
 649         s->secondary_disk = NULL;
 650         s->hidden_disk = NULL;
 651         s->error = 0;
 652     } else {
 653         s->stage = BLOCK_REPLICATION_FAILOVER_FAILED;
 654         s->error = -EIO;
 655     }
 656 }
 657
 658 static void replication_stop(ReplicationState *rs, bool failover, Error **errp)
 659 {
 660     BlockDriverState *bs = rs->opaque;
 661     BDRVReplicationState *s;
 662     AioContext *aio_context;
 663
 664     aio_context = bdrv_get_aio_context(bs);
 665     aio_context_acquire(aio_context);
 666     s = bs->opaque;
 667
 668     if (s->stage == BLOCK_REPLICATION_DONE ||
 669         s->stage == BLOCK_REPLICATION_FAILOVER) {
 670         /*
 671          * This case happens when a secondary was promoted to primary.
 672          * Ignore the request because the secondary side of replication
 673          * doesn't have to do anything anymore.
 674          */
 675         aio_context_release(aio_context);
 676         return;
 677     }
 678
 679     if (s->stage != BLOCK_REPLICATION_RUNNING) {
 680         error_setg(errp, "Block replication is not running");
 681         aio_context_release(aio_context);
 682         return;
 683     }
 684
 685     switch (s->mode) {
 686     case REPLICATION_MODE_PRIMARY:
 687         s->stage = BLOCK_REPLICATION_DONE;
 688         s->error = 0;
 689         break;
 690     case REPLICATION_MODE_SECONDARY:
 691         /*
 692          * This BDS will be closed, and the job should be completed
 693          * before the BDS is closed, because we will access hidden
 694          * disk, secondary disk in backup_job_completed().
 695          */
 696         if (s->backup_job) {
 697             job_cancel_sync(&s->backup_job->job);
 698         }
 699
 700         if (!failover) {
 701             secondary_do_checkpoint(s, errp);
 702             s->stage = BLOCK_REPLICATION_DONE;
 703             aio_context_release(aio_context);
 704             return;
 705         }
 706
 707         s->stage = BLOCK_REPLICATION_FAILOVER;
 708         s->commit_job = commit_active_start(
 709                             NULL, s->active_disk->bs, s->secondary_disk->bs,
 710                             JOB_INTERNAL, 0, BLOCKDEV_ON_ERROR_REPORT,
 711                             NULL, replication_done, bs, true, errp);
 712         break;
 713     default:
 714         aio_context_release(aio_context);
 715         abort();
 716     }
 717     aio_context_release(aio_context);
 718 }
 719
 720 static const char *const replication_strong_runtime_opts[] = {
 721     REPLICATION_MODE,
 722     REPLICATION_TOP_ID,
 723
 724     NULL
 725 };
 726
 727 static BlockDriver bdrv_replication = {
 728     .format_name                = "replication",
 729     .instance_size              = sizeof(BDRVReplicationState),
 730
 731     .bdrv_open                  = replication_open,
 732     .bdrv_close                 = replication_close,
 733     .bdrv_child_perm            = replication_child_perm,
 734
 735     .bdrv_getlength             = replication_getlength,
 736     .bdrv_co_readv              = replication_co_readv,
 737     .bdrv_co_writev             = replication_co_writev,
 738
 739     .is_filter                  = true,
 740
 741     .has_variable_length        = true,
 742     .strong_runtime_opts        = replication_strong_runtime_opts,
 743 };
 744
 745 static void bdrv_replication_init(void)
 746 {
 747     bdrv_register(&bdrv_replication);
 748 }
 749
 750 block_init(bdrv_replication_init);