block/blkdebug.c

   1 /*
   2  * Block protocol for I/O error injection
   3  *
   4  * Copyright (c) 2010 Kevin Wolf <[email protected]>
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24
  25 #include "qemu-common.h"
  26 #include "qemu/config-file.h"
  27 #include "block/block_int.h"
  28 #include "qemu/module.h"
  29
  30 typedef struct BDRVBlkdebugState {
  31     int state;
  32     int new_state;
  33
  34     QLIST_HEAD(, BlkdebugRule) rules[BLKDBG_EVENT_MAX];
  35     QSIMPLEQ_HEAD(, BlkdebugRule) active_rules;
  36     QLIST_HEAD(, BlkdebugSuspendedReq) suspended_reqs;
  37 } BDRVBlkdebugState;
  38
  39 typedef struct BlkdebugAIOCB {
  40     BlockDriverAIOCB common;
  41     QEMUBH *bh;
  42     int ret;
  43 } BlkdebugAIOCB;
  44
  45 typedef struct BlkdebugSuspendedReq {
  46     Coroutine *co;
  47     char *tag;
  48     QLIST_ENTRY(BlkdebugSuspendedReq) next;
  49 } BlkdebugSuspendedReq;
  50
  51 static void blkdebug_aio_cancel(BlockDriverAIOCB *blockacb);
  52
  53 static const AIOCBInfo blkdebug_aiocb_info = {
  54     .aiocb_size = sizeof(BlkdebugAIOCB),
  55     .cancel     = blkdebug_aio_cancel,
  56 };
  57
  58 enum {
  59     ACTION_INJECT_ERROR,
  60     ACTION_SET_STATE,
  61     ACTION_SUSPEND,
  62 };
  63
  64 typedef struct BlkdebugRule {
  65     BlkDebugEvent event;
  66     int action;
  67     int state;
  68     union {
  69         struct {
  70             int error;
  71             int immediately;
  72             int once;
  73             int64_t sector;
  74         } inject;
  75         struct {
  76             int new_state;
  77         } set_state;
  78         struct {
  79             char *tag;
  80         } suspend;
  81     } options;
  82     QLIST_ENTRY(BlkdebugRule) next;
  83     QSIMPLEQ_ENTRY(BlkdebugRule) active_next;
  84 } BlkdebugRule;
  85
  86 static QemuOptsList inject_error_opts = {
  87     .name = "inject-error",
  88     .head = QTAILQ_HEAD_INITIALIZER(inject_error_opts.head),
  89     .desc = {
  90         {
  91             .name = "event",
  92             .type = QEMU_OPT_STRING,
  93         },
  94         {
  95             .name = "state",
  96             .type = QEMU_OPT_NUMBER,
  97         },
  98         {
  99             .name = "errno",
 100             .type = QEMU_OPT_NUMBER,
 101         },
 102         {
 103             .name = "sector",
 104             .type = QEMU_OPT_NUMBER,
 105         },
 106         {
 107             .name = "once",
 108             .type = QEMU_OPT_BOOL,
 109         },
 110         {
 111             .name = "immediately",
 112             .type = QEMU_OPT_BOOL,
 113         },
 114         { /* end of list */ }
 115     },
 116 };
 117
 118 static QemuOptsList set_state_opts = {
 119     .name = "set-state",
 120     .head = QTAILQ_HEAD_INITIALIZER(set_state_opts.head),
 121     .desc = {
 122         {
 123             .name = "event",
 124             .type = QEMU_OPT_STRING,
 125         },
 126         {
 127             .name = "state",
 128             .type = QEMU_OPT_NUMBER,
 129         },
 130         {
 131             .name = "new_state",
 132             .type = QEMU_OPT_NUMBER,
 133         },
 134         { /* end of list */ }
 135     },
 136 };
 137
 138 static QemuOptsList *config_groups[] = {
 139     &inject_error_opts,
 140     &set_state_opts,
 141     NULL
 142 };
 143
 144 static const char *event_names[BLKDBG_EVENT_MAX] = {
 145     [BLKDBG_L1_UPDATE]                      = "l1_update",
 146     [BLKDBG_L1_GROW_ALLOC_TABLE]            = "l1_grow.alloc_table",
 147     [BLKDBG_L1_GROW_WRITE_TABLE]            = "l1_grow.write_table",
 148     [BLKDBG_L1_GROW_ACTIVATE_TABLE]         = "l1_grow.activate_table",
 149
 150     [BLKDBG_L2_LOAD]                        = "l2_load",
 151     [BLKDBG_L2_UPDATE]                      = "l2_update",
 152     [BLKDBG_L2_UPDATE_COMPRESSED]           = "l2_update_compressed",
 153     [BLKDBG_L2_ALLOC_COW_READ]              = "l2_alloc.cow_read",
 154     [BLKDBG_L2_ALLOC_WRITE]                 = "l2_alloc.write",
 155
 156     [BLKDBG_READ_AIO]                       = "read_aio",
 157     [BLKDBG_READ_BACKING_AIO]               = "read_backing_aio",
 158     [BLKDBG_READ_COMPRESSED]                = "read_compressed",
 159
 160     [BLKDBG_WRITE_AIO]                      = "write_aio",
 161     [BLKDBG_WRITE_COMPRESSED]               = "write_compressed",
 162
 163     [BLKDBG_VMSTATE_LOAD]                   = "vmstate_load",
 164     [BLKDBG_VMSTATE_SAVE]                   = "vmstate_save",
 165
 166     [BLKDBG_COW_READ]                       = "cow_read",
 167     [BLKDBG_COW_WRITE]                      = "cow_write",
 168
 169     [BLKDBG_REFTABLE_LOAD]                  = "reftable_load",
 170     [BLKDBG_REFTABLE_GROW]                  = "reftable_grow",
 171     [BLKDBG_REFTABLE_UPDATE]                = "reftable_update",
 172
 173     [BLKDBG_REFBLOCK_LOAD]                  = "refblock_load",
 174     [BLKDBG_REFBLOCK_UPDATE]                = "refblock_update",
 175     [BLKDBG_REFBLOCK_UPDATE_PART]           = "refblock_update_part",
 176     [BLKDBG_REFBLOCK_ALLOC]                 = "refblock_alloc",
 177     [BLKDBG_REFBLOCK_ALLOC_HOOKUP]          = "refblock_alloc.hookup",
 178     [BLKDBG_REFBLOCK_ALLOC_WRITE]           = "refblock_alloc.write",
 179     [BLKDBG_REFBLOCK_ALLOC_WRITE_BLOCKS]    = "refblock_alloc.write_blocks",
 180     [BLKDBG_REFBLOCK_ALLOC_WRITE_TABLE]     = "refblock_alloc.write_table",
 181     [BLKDBG_REFBLOCK_ALLOC_SWITCH_TABLE]    = "refblock_alloc.switch_table",
 182
 183     [BLKDBG_CLUSTER_ALLOC]                  = "cluster_alloc",
 184     [BLKDBG_CLUSTER_ALLOC_BYTES]            = "cluster_alloc_bytes",
 185     [BLKDBG_CLUSTER_FREE]                   = "cluster_free",
 186
 187     [BLKDBG_FLUSH_TO_OS]                    = "flush_to_os",
 188     [BLKDBG_FLUSH_TO_DISK]                  = "flush_to_disk",
 189 };
 190
 191 static int get_event_by_name(const char *name, BlkDebugEvent *event)
 192 {
 193     int i;
 194
 195     for (i = 0; i < BLKDBG_EVENT_MAX; i++) {
 196         if (!strcmp(event_names[i], name)) {
 197             *event = i;
 198             return 0;
 199         }
 200     }
 201
 202     return -1;
 203 }
 204
 205 struct add_rule_data {
 206     BDRVBlkdebugState *s;
 207     int action;
 208 };
 209
 210 static int add_rule(QemuOpts *opts, void *opaque)
 211 {
 212     struct add_rule_data *d = opaque;
 213     BDRVBlkdebugState *s = d->s;
 214     const char* event_name;
 215     BlkDebugEvent event;
 216     struct BlkdebugRule *rule;
 217
 218     /* Find the right event for the rule */
 219     event_name = qemu_opt_get(opts, "event");
 220     if (!event_name || get_event_by_name(event_name, &event) < 0) {
 221         return -1;
 222     }
 223
 224     /* Set attributes common for all actions */
 225     rule = g_malloc0(sizeof(*rule));
 226     *rule = (struct BlkdebugRule) {
 227         .event  = event,
 228         .action = d->action,
 229         .state  = qemu_opt_get_number(opts, "state", 0),
 230     };
 231
 232     /* Parse action-specific options */
 233     switch (d->action) {
 234     case ACTION_INJECT_ERROR:
 235         rule->options.inject.error = qemu_opt_get_number(opts, "errno", EIO);
 236         rule->options.inject.once  = qemu_opt_get_bool(opts, "once", 0);
 237         rule->options.inject.immediately =
 238             qemu_opt_get_bool(opts, "immediately", 0);
 239         rule->options.inject.sector = qemu_opt_get_number(opts, "sector", -1);
 240         break;
 241
 242     case ACTION_SET_STATE:
 243         rule->options.set_state.new_state =
 244             qemu_opt_get_number(opts, "new_state", 0);
 245         break;
 246
 247     case ACTION_SUSPEND:
 248         rule->options.suspend.tag =
 249             g_strdup(qemu_opt_get(opts, "tag"));
 250         break;
 251     };
 252
 253     /* Add the rule */
 254     QLIST_INSERT_HEAD(&s->rules[event], rule, next);
 255
 256     return 0;
 257 }
 258
 259 static void remove_rule(BlkdebugRule *rule)
 260 {
 261     switch (rule->action) {
 262     case ACTION_INJECT_ERROR:
 263     case ACTION_SET_STATE:
 264         break;
 265     case ACTION_SUSPEND:
 266         g_free(rule->options.suspend.tag);
 267         break;
 268     }
 269
 270     QLIST_REMOVE(rule, next);
 271     g_free(rule);
 272 }
 273
 274 static int read_config(BDRVBlkdebugState *s, const char *filename,
 275                        QDict *options, Error **errp)
 276 {
 277     FILE *f = NULL;
 278     int ret;
 279     struct add_rule_data d;
 280     Error *local_err = NULL;
 281
 282     if (filename) {
 283         f = fopen(filename, "r");
 284         if (f == NULL) {
 285             error_setg_errno(errp, errno, "Could not read blkdebug config file");
 286             return -errno;
 287         }
 288
 289         ret = qemu_config_parse(f, config_groups, filename);
 290         if (ret < 0) {
 291             error_setg(errp, "Could not parse blkdebug config file");
 292             ret = -EINVAL;
 293             goto fail;
 294         }
 295     }
 296
 297     qemu_config_parse_qdict(options, config_groups, &local_err);
 298     if (error_is_set(&local_err)) {
 299         error_propagate(errp, local_err);
 300         ret = -EINVAL;
 301         goto fail;
 302     }
 303
 304     d.s = s;
 305     d.action = ACTION_INJECT_ERROR;
 306     qemu_opts_foreach(&inject_error_opts, add_rule, &d, 0);
 307
 308     d.action = ACTION_SET_STATE;
 309     qemu_opts_foreach(&set_state_opts, add_rule, &d, 0);
 310
 311     ret = 0;
 312 fail:
 313     qemu_opts_reset(&inject_error_opts);
 314     qemu_opts_reset(&set_state_opts);
 315     if (f) {
 316         fclose(f);
 317     }
 318     return ret;
 319 }
 320
 321 /* Valid blkdebug filenames look like blkdebug:path/to/config:path/to/image */
 322 static void blkdebug_parse_filename(const char *filename, QDict *options,
 323                                     Error **errp)
 324 {
 325     const char *c;
 326
 327     /* Parse the blkdebug: prefix */
 328     if (!strstart(filename, "blkdebug:", &filename)) {
 329         /* There was no prefix; therefore, all options have to be already
 330            present in the QDict (except for the filename) */
 331         qdict_put(options, "x-image", qstring_from_str(filename));
 332         return;
 333     }
 334
 335     /* Parse config file path */
 336     c = strchr(filename, ':');
 337     if (c == NULL) {
 338         error_setg(errp, "blkdebug requires both config file and image path");
 339         return;
 340     }
 341
 342     if (c != filename) {
 343         QString *config_path;
 344         config_path = qstring_from_substr(filename, 0, c - filename - 1);
 345         qdict_put(options, "config", config_path);
 346     }
 347
 348     /* TODO Allow multi-level nesting and set file.filename here */
 349     filename = c + 1;
 350     qdict_put(options, "x-image", qstring_from_str(filename));
 351 }
 352
 353 static QemuOptsList runtime_opts = {
 354     .name = "blkdebug",
 355     .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
 356     .desc = {
 357         {
 358             .name = "config",
 359             .type = QEMU_OPT_STRING,
 360             .help = "Path to the configuration file",
 361         },
 362         {
 363             .name = "x-image",
 364             .type = QEMU_OPT_STRING,
 365             .help = "[internal use only, will be removed]",
 366         },
 367         { /* end of list */ }
 368     },
 369 };
 370
 371 static int blkdebug_open(BlockDriverState *bs, QDict *options, int flags,
 372                          Error **errp)
 373 {
 374     BDRVBlkdebugState *s = bs->opaque;
 375     QemuOpts *opts;
 376     Error *local_err = NULL;
 377     const char *config;
 378     int ret;
 379
 380     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
 381     qemu_opts_absorb_qdict(opts, options, &local_err);
 382     if (error_is_set(&local_err)) {
 383         error_propagate(errp, local_err);
 384         ret = -EINVAL;
 385         goto fail;
 386     }
 387
 388     /* Read rules from config file or command line options */
 389     config = qemu_opt_get(opts, "config");
 390     ret = read_config(s, config, options, errp);
 391     if (ret) {
 392         goto fail;
 393     }
 394
 395     /* Set initial state */
 396     s->state = 1;
 397
 398     /* Open the backing file */
 399     ret = bdrv_open_image(&bs->file, qemu_opt_get(opts, "x-image"), options, "image",
 400                           flags, true, false, &local_err);
 401     if (ret < 0) {
 402         error_propagate(errp, local_err);
 403         goto fail;
 404     }
 405
 406     ret = 0;
 407 fail:
 408     qemu_opts_del(opts);
 409     return ret;
 410 }
 411
 412 static void error_callback_bh(void *opaque)
 413 {
 414     struct BlkdebugAIOCB *acb = opaque;
 415     qemu_bh_delete(acb->bh);
 416     acb->common.cb(acb->common.opaque, acb->ret);
 417     qemu_aio_release(acb);
 418 }
 419
 420 static void blkdebug_aio_cancel(BlockDriverAIOCB *blockacb)
 421 {
 422     BlkdebugAIOCB *acb = container_of(blockacb, BlkdebugAIOCB, common);
 423     qemu_aio_release(acb);
 424 }
 425
 426 static BlockDriverAIOCB *inject_error(BlockDriverState *bs,
 427     BlockDriverCompletionFunc *cb, void *opaque, BlkdebugRule *rule)
 428 {
 429     BDRVBlkdebugState *s = bs->opaque;
 430     int error = rule->options.inject.error;
 431     struct BlkdebugAIOCB *acb;
 432     QEMUBH *bh;
 433
 434     if (rule->options.inject.once) {
 435         QSIMPLEQ_INIT(&s->active_rules);
 436     }
 437
 438     if (rule->options.inject.immediately) {
 439         return NULL;
 440     }
 441
 442     acb = qemu_aio_get(&blkdebug_aiocb_info, bs, cb, opaque);
 443     acb->ret = -error;
 444
 445     bh = qemu_bh_new(error_callback_bh, acb);
 446     acb->bh = bh;
 447     qemu_bh_schedule(bh);
 448
 449     return &acb->common;
 450 }
 451
 452 static BlockDriverAIOCB *blkdebug_aio_readv(BlockDriverState *bs,
 453     int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 454     BlockDriverCompletionFunc *cb, void *opaque)
 455 {
 456     BDRVBlkdebugState *s = bs->opaque;
 457     BlkdebugRule *rule = NULL;
 458
 459     QSIMPLEQ_FOREACH(rule, &s->active_rules, active_next) {
 460         if (rule->options.inject.sector == -1 ||
 461             (rule->options.inject.sector >= sector_num &&
 462              rule->options.inject.sector < sector_num + nb_sectors)) {
 463             break;
 464         }
 465     }
 466
 467     if (rule && rule->options.inject.error) {
 468         return inject_error(bs, cb, opaque, rule);
 469     }
 470
 471     return bdrv_aio_readv(bs->file, sector_num, qiov, nb_sectors, cb, opaque);
 472 }
 473
 474 static BlockDriverAIOCB *blkdebug_aio_writev(BlockDriverState *bs,
 475     int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 476     BlockDriverCompletionFunc *cb, void *opaque)
 477 {
 478     BDRVBlkdebugState *s = bs->opaque;
 479     BlkdebugRule *rule = NULL;
 480
 481     QSIMPLEQ_FOREACH(rule, &s->active_rules, active_next) {
 482         if (rule->options.inject.sector == -1 ||
 483             (rule->options.inject.sector >= sector_num &&
 484              rule->options.inject.sector < sector_num + nb_sectors)) {
 485             break;
 486         }
 487     }
 488
 489     if (rule && rule->options.inject.error) {
 490         return inject_error(bs, cb, opaque, rule);
 491     }
 492
 493     return bdrv_aio_writev(bs->file, sector_num, qiov, nb_sectors, cb, opaque);
 494 }
 495
 496
 497 static void blkdebug_close(BlockDriverState *bs)
 498 {
 499     BDRVBlkdebugState *s = bs->opaque;
 500     BlkdebugRule *rule, *next;
 501     int i;
 502
 503     for (i = 0; i < BLKDBG_EVENT_MAX; i++) {
 504         QLIST_FOREACH_SAFE(rule, &s->rules[i], next, next) {
 505             remove_rule(rule);
 506         }
 507     }
 508 }
 509
 510 static void suspend_request(BlockDriverState *bs, BlkdebugRule *rule)
 511 {
 512     BDRVBlkdebugState *s = bs->opaque;
 513     BlkdebugSuspendedReq r;
 514
 515     r = (BlkdebugSuspendedReq) {
 516         .co         = qemu_coroutine_self(),
 517         .tag        = g_strdup(rule->options.suspend.tag),
 518     };
 519
 520     remove_rule(rule);
 521     QLIST_INSERT_HEAD(&s->suspended_reqs, &r, next);
 522
 523     printf("blkdebug: Suspended request '%s'\n", r.tag);
 524     qemu_coroutine_yield();
 525     printf("blkdebug: Resuming request '%s'\n", r.tag);
 526
 527     QLIST_REMOVE(&r, next);
 528     g_free(r.tag);
 529 }
 530
 531 static bool process_rule(BlockDriverState *bs, struct BlkdebugRule *rule,
 532     bool injected)
 533 {
 534     BDRVBlkdebugState *s = bs->opaque;
 535
 536     /* Only process rules for the current state */
 537     if (rule->state && rule->state != s->state) {
 538         return injected;
 539     }
 540
 541     /* Take the action */
 542     switch (rule->action) {
 543     case ACTION_INJECT_ERROR:
 544         if (!injected) {
 545             QSIMPLEQ_INIT(&s->active_rules);
 546             injected = true;
 547         }
 548         QSIMPLEQ_INSERT_HEAD(&s->active_rules, rule, active_next);
 549         break;
 550
 551     case ACTION_SET_STATE:
 552         s->new_state = rule->options.set_state.new_state;
 553         break;
 554
 555     case ACTION_SUSPEND:
 556         suspend_request(bs, rule);
 557         break;
 558     }
 559     return injected;
 560 }
 561
 562 static void blkdebug_debug_event(BlockDriverState *bs, BlkDebugEvent event)
 563 {
 564     BDRVBlkdebugState *s = bs->opaque;
 565     struct BlkdebugRule *rule, *next;
 566     bool injected;
 567
 568     assert((int)event >= 0 && event < BLKDBG_EVENT_MAX);
 569
 570     injected = false;
 571     s->new_state = s->state;
 572     QLIST_FOREACH_SAFE(rule, &s->rules[event], next, next) {
 573         injected = process_rule(bs, rule, injected);
 574     }
 575     s->state = s->new_state;
 576 }
 577
 578 static int blkdebug_debug_breakpoint(BlockDriverState *bs, const char *event,
 579                                      const char *tag)
 580 {
 581     BDRVBlkdebugState *s = bs->opaque;
 582     struct BlkdebugRule *rule;
 583     BlkDebugEvent blkdebug_event;
 584
 585     if (get_event_by_name(event, &blkdebug_event) < 0) {
 586         return -ENOENT;
 587     }
 588
 589
 590     rule = g_malloc(sizeof(*rule));
 591     *rule = (struct BlkdebugRule) {
 592         .event  = blkdebug_event,
 593         .action = ACTION_SUSPEND,
 594         .state  = 0,
 595         .options.suspend.tag = g_strdup(tag),
 596     };
 597
 598     QLIST_INSERT_HEAD(&s->rules[blkdebug_event], rule, next);
 599
 600     return 0;
 601 }
 602
 603 static int blkdebug_debug_resume(BlockDriverState *bs, const char *tag)
 604 {
 605     BDRVBlkdebugState *s = bs->opaque;
 606     BlkdebugSuspendedReq *r, *next;
 607
 608     QLIST_FOREACH_SAFE(r, &s->suspended_reqs, next, next) {
 609         if (!strcmp(r->tag, tag)) {
 610             qemu_coroutine_enter(r->co, NULL);
 611             return 0;
 612         }
 613     }
 614     return -ENOENT;
 615 }
 616
 617 static int blkdebug_debug_remove_breakpoint(BlockDriverState *bs,
 618                                             const char *tag)
 619 {
 620     BDRVBlkdebugState *s = bs->opaque;
 621     BlkdebugSuspendedReq *r, *r_next;
 622     BlkdebugRule *rule, *next;
 623     int i, ret = -ENOENT;
 624
 625     for (i = 0; i < BLKDBG_EVENT_MAX; i++) {
 626         QLIST_FOREACH_SAFE(rule, &s->rules[i], next, next) {
 627             if (rule->action == ACTION_SUSPEND &&
 628                 !strcmp(rule->options.suspend.tag, tag)) {
 629                 remove_rule(rule);
 630                 ret = 0;
 631             }
 632         }
 633     }
 634     QLIST_FOREACH_SAFE(r, &s->suspended_reqs, next, r_next) {
 635         if (!strcmp(r->tag, tag)) {
 636             qemu_coroutine_enter(r->co, NULL);
 637             ret = 0;
 638         }
 639     }
 640     return ret;
 641 }
 642
 643 static bool blkdebug_debug_is_suspended(BlockDriverState *bs, const char *tag)
 644 {
 645     BDRVBlkdebugState *s = bs->opaque;
 646     BlkdebugSuspendedReq *r;
 647
 648     QLIST_FOREACH(r, &s->suspended_reqs, next) {
 649         if (!strcmp(r->tag, tag)) {
 650             return true;
 651         }
 652     }
 653     return false;
 654 }
 655
 656 static int64_t blkdebug_getlength(BlockDriverState *bs)
 657 {
 658     return bdrv_getlength(bs->file);
 659 }
 660
 661 static BlockDriver bdrv_blkdebug = {
 662     .format_name            = "blkdebug",
 663     .protocol_name          = "blkdebug",
 664     .instance_size          = sizeof(BDRVBlkdebugState),
 665
 666     .bdrv_parse_filename    = blkdebug_parse_filename,
 667     .bdrv_file_open         = blkdebug_open,
 668     .bdrv_close             = blkdebug_close,
 669     .bdrv_getlength         = blkdebug_getlength,
 670
 671     .bdrv_aio_readv         = blkdebug_aio_readv,
 672     .bdrv_aio_writev        = blkdebug_aio_writev,
 673
 674     .bdrv_debug_event           = blkdebug_debug_event,
 675     .bdrv_debug_breakpoint      = blkdebug_debug_breakpoint,
 676     .bdrv_debug_remove_breakpoint
 677                                 = blkdebug_debug_remove_breakpoint,
 678     .bdrv_debug_resume          = blkdebug_debug_resume,
 679     .bdrv_debug_is_suspended    = blkdebug_debug_is_suspended,
 680 };
 681
 682 static void bdrv_blkdebug_init(void)
 683 {
 684     bdrv_register(&bdrv_blkdebug);
 685 }
 686
 687 block_init(bdrv_blkdebug_init);