block/blkdebug.c

   1 /*
   2  * Block protocol for I/O error injection
   3  *
   4  * Copyright (c) 2010 Kevin Wolf <kwolf@redhat.com>
   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     [BLKDBG_PWRITEV_RMW_HEAD]               = "pwritev_rmw.head",
 191     [BLKDBG_PWRITEV_RMW_AFTER_HEAD]         = "pwritev_rmw.after_head",
 192     [BLKDBG_PWRITEV_RMW_TAIL]               = "pwritev_rmw.tail",
 193     [BLKDBG_PWRITEV_RMW_AFTER_TAIL]         = "pwritev_rmw.after_tail",
 194     [BLKDBG_PWRITEV]                        = "pwritev",
 195     [BLKDBG_PWRITEV_ZERO]                   = "pwritev_zero",
 196     [BLKDBG_PWRITEV_DONE]                   = "pwritev_done",
 197 };
 198
 199 static int get_event_by_name(const char *name, BlkDebugEvent *event)
 200 {
 201     int i;
 202
 203     for (i = 0; i < BLKDBG_EVENT_MAX; i++) {
 204         if (!strcmp(event_names[i], name)) {
 205             *event = i;
 206             return 0;
 207         }
 208     }
 209
 210     return -1;
 211 }
 212
 213 struct add_rule_data {
 214     BDRVBlkdebugState *s;
 215     int action;
 216 };
 217
 218 static int add_rule(QemuOpts *opts, void *opaque)
 219 {
 220     struct add_rule_data *d = opaque;
 221     BDRVBlkdebugState *s = d->s;
 222     const char* event_name;
 223     BlkDebugEvent event;
 224     struct BlkdebugRule *rule;
 225
 226     /* Find the right event for the rule */
 227     event_name = qemu_opt_get(opts, "event");
 228     if (!event_name || get_event_by_name(event_name, &event) < 0) {
 229         return -1;
 230     }
 231
 232     /* Set attributes common for all actions */
 233     rule = g_malloc0(sizeof(*rule));
 234     *rule = (struct BlkdebugRule) {
 235         .event  = event,
 236         .action = d->action,
 237         .state  = qemu_opt_get_number(opts, "state", 0),
 238     };
 239
 240     /* Parse action-specific options */
 241     switch (d->action) {
 242     case ACTION_INJECT_ERROR:
 243         rule->options.inject.error = qemu_opt_get_number(opts, "errno", EIO);
 244         rule->options.inject.once  = qemu_opt_get_bool(opts, "once", 0);
 245         rule->options.inject.immediately =
 246             qemu_opt_get_bool(opts, "immediately", 0);
 247         rule->options.inject.sector = qemu_opt_get_number(opts, "sector", -1);
 248         break;
 249
 250     case ACTION_SET_STATE:
 251         rule->options.set_state.new_state =
 252             qemu_opt_get_number(opts, "new_state", 0);
 253         break;
 254
 255     case ACTION_SUSPEND:
 256         rule->options.suspend.tag =
 257             g_strdup(qemu_opt_get(opts, "tag"));
 258         break;
 259     };
 260
 261     /* Add the rule */
 262     QLIST_INSERT_HEAD(&s->rules[event], rule, next);
 263
 264     return 0;
 265 }
 266
 267 static void remove_rule(BlkdebugRule *rule)
 268 {
 269     switch (rule->action) {
 270     case ACTION_INJECT_ERROR:
 271     case ACTION_SET_STATE:
 272         break;
 273     case ACTION_SUSPEND:
 274         g_free(rule->options.suspend.tag);
 275         break;
 276     }
 277
 278     QLIST_REMOVE(rule, next);
 279     g_free(rule);
 280 }
 281
 282 static int read_config(BDRVBlkdebugState *s, const char *filename,
 283                        QDict *options, Error **errp)
 284 {
 285     FILE *f = NULL;
 286     int ret;
 287     struct add_rule_data d;
 288     Error *local_err = NULL;
 289
 290     if (filename) {
 291         f = fopen(filename, "r");
 292         if (f == NULL) {
 293             error_setg_errno(errp, errno, "Could not read blkdebug config file");
 294             return -errno;
 295         }
 296
 297         ret = qemu_config_parse(f, config_groups, filename);
 298         if (ret < 0) {
 299             error_setg(errp, "Could not parse blkdebug config file");
 300             ret = -EINVAL;
 301             goto fail;
 302         }
 303     }
 304
 305     qemu_config_parse_qdict(options, config_groups, &local_err);
 306     if (error_is_set(&local_err)) {
 307         error_propagate(errp, local_err);
 308         ret = -EINVAL;
 309         goto fail;
 310     }
 311
 312     d.s = s;
 313     d.action = ACTION_INJECT_ERROR;
 314     qemu_opts_foreach(&inject_error_opts, add_rule, &d, 0);
 315
 316     d.action = ACTION_SET_STATE;
 317     qemu_opts_foreach(&set_state_opts, add_rule, &d, 0);
 318
 319     ret = 0;
 320 fail:
 321     qemu_opts_reset(&inject_error_opts);
 322     qemu_opts_reset(&set_state_opts);
 323     if (f) {
 324         fclose(f);
 325     }
 326     return ret;
 327 }
 328
 329 /* Valid blkdebug filenames look like blkdebug:path/to/config:path/to/image */
 330 static void blkdebug_parse_filename(const char *filename, QDict *options,
 331                                     Error **errp)
 332 {
 333     const char *c;
 334
 335     /* Parse the blkdebug: prefix */
 336     if (!strstart(filename, "blkdebug:", &filename)) {
 337         /* There was no prefix; therefore, all options have to be already
 338            present in the QDict (except for the filename) */
 339         qdict_put(options, "x-image", qstring_from_str(filename));
 340         return;
 341     }
 342
 343     /* Parse config file path */
 344     c = strchr(filename, ':');
 345     if (c == NULL) {
 346         error_setg(errp, "blkdebug requires both config file and image path");
 347         return;
 348     }
 349
 350     if (c != filename) {
 351         QString *config_path;
 352         config_path = qstring_from_substr(filename, 0, c - filename - 1);
 353         qdict_put(options, "config", config_path);
 354     }
 355
 356     /* TODO Allow multi-level nesting and set file.filename here */
 357     filename = c + 1;
 358     qdict_put(options, "x-image", qstring_from_str(filename));
 359 }
 360
 361 static QemuOptsList runtime_opts = {
 362     .name = "blkdebug",
 363     .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
 364     .desc = {
 365         {
 366             .name = "config",
 367             .type = QEMU_OPT_STRING,
 368             .help = "Path to the configuration file",
 369         },
 370         {
 371             .name = "x-image",
 372             .type = QEMU_OPT_STRING,
 373             .help = "[internal use only, will be removed]",
 374         },
 375         {
 376             .name = "align",
 377             .type = QEMU_OPT_SIZE,
 378             .help = "Required alignment in bytes",
 379         },
 380         { /* end of list */ }
 381     },
 382 };
 383
 384 static int blkdebug_open(BlockDriverState *bs, QDict *options, int flags,
 385                          Error **errp)
 386 {
 387     BDRVBlkdebugState *s = bs->opaque;
 388     QemuOpts *opts;
 389     Error *local_err = NULL;
 390     const char *config;
 391     uint64_t align;
 392     int ret;
 393
 394     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
 395     qemu_opts_absorb_qdict(opts, options, &local_err);
 396     if (error_is_set(&local_err)) {
 397         error_propagate(errp, local_err);
 398         ret = -EINVAL;
 399         goto out;
 400     }
 401
 402     /* Read rules from config file or command line options */
 403     config = qemu_opt_get(opts, "config");
 404     ret = read_config(s, config, options, errp);
 405     if (ret) {
 406         goto out;
 407     }
 408
 409     /* Set initial state */
 410     s->state = 1;
 411
 412     /* Open the backing file */
 413     ret = bdrv_open_image(&bs->file, qemu_opt_get(opts, "x-image"), options, "image",
 414                           flags, true, false, &local_err);
 415     if (ret < 0) {
 416         error_propagate(errp, local_err);
 417         goto out;
 418     }
 419
 420     /* Set request alignment */
 421     align = qemu_opt_get_size(opts, "align", bs->request_alignment);
 422     if (align > 0 && align < INT_MAX && !(align & (align - 1))) {
 423         bs->request_alignment = align;
 424     } else {
 425         error_setg(errp, "Invalid alignment");
 426         ret = -EINVAL;
 427         goto fail_unref;
 428     }
 429
 430     ret = 0;
 431     goto out;
 432
 433 fail_unref:
 434     bdrv_unref(bs->file);
 435 out:
 436     qemu_opts_del(opts);
 437     return ret;
 438 }
 439
 440 static void error_callback_bh(void *opaque)
 441 {
 442     struct BlkdebugAIOCB *acb = opaque;
 443     qemu_bh_delete(acb->bh);
 444     acb->common.cb(acb->common.opaque, acb->ret);
 445     qemu_aio_release(acb);
 446 }
 447
 448 static void blkdebug_aio_cancel(BlockDriverAIOCB *blockacb)
 449 {
 450     BlkdebugAIOCB *acb = container_of(blockacb, BlkdebugAIOCB, common);
 451     qemu_aio_release(acb);
 452 }
 453
 454 static BlockDriverAIOCB *inject_error(BlockDriverState *bs,
 455     BlockDriverCompletionFunc *cb, void *opaque, BlkdebugRule *rule)
 456 {
 457     BDRVBlkdebugState *s = bs->opaque;
 458     int error = rule->options.inject.error;
 459     struct BlkdebugAIOCB *acb;
 460     QEMUBH *bh;
 461
 462     if (rule->options.inject.once) {
 463         QSIMPLEQ_INIT(&s->active_rules);
 464     }
 465
 466     if (rule->options.inject.immediately) {
 467         return NULL;
 468     }
 469
 470     acb = qemu_aio_get(&blkdebug_aiocb_info, bs, cb, opaque);
 471     acb->ret = -error;
 472
 473     bh = qemu_bh_new(error_callback_bh, acb);
 474     acb->bh = bh;
 475     qemu_bh_schedule(bh);
 476
 477     return &acb->common;
 478 }
 479
 480 static BlockDriverAIOCB *blkdebug_aio_readv(BlockDriverState *bs,
 481     int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 482     BlockDriverCompletionFunc *cb, void *opaque)
 483 {
 484     BDRVBlkdebugState *s = bs->opaque;
 485     BlkdebugRule *rule = NULL;
 486
 487     QSIMPLEQ_FOREACH(rule, &s->active_rules, active_next) {
 488         if (rule->options.inject.sector == -1 ||
 489             (rule->options.inject.sector >= sector_num &&
 490              rule->options.inject.sector < sector_num + nb_sectors)) {
 491             break;
 492         }
 493     }
 494
 495     if (rule && rule->options.inject.error) {
 496         return inject_error(bs, cb, opaque, rule);
 497     }
 498
 499     return bdrv_aio_readv(bs->file, sector_num, qiov, nb_sectors, cb, opaque);
 500 }
 501
 502 static BlockDriverAIOCB *blkdebug_aio_writev(BlockDriverState *bs,
 503     int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 504     BlockDriverCompletionFunc *cb, void *opaque)
 505 {
 506     BDRVBlkdebugState *s = bs->opaque;
 507     BlkdebugRule *rule = NULL;
 508
 509     QSIMPLEQ_FOREACH(rule, &s->active_rules, active_next) {
 510         if (rule->options.inject.sector == -1 ||
 511             (rule->options.inject.sector >= sector_num &&
 512              rule->options.inject.sector < sector_num + nb_sectors)) {
 513             break;
 514         }
 515     }
 516
 517     if (rule && rule->options.inject.error) {
 518         return inject_error(bs, cb, opaque, rule);
 519     }
 520
 521     return bdrv_aio_writev(bs->file, sector_num, qiov, nb_sectors, cb, opaque);
 522 }
 523
 524
 525 static void blkdebug_close(BlockDriverState *bs)
 526 {
 527     BDRVBlkdebugState *s = bs->opaque;
 528     BlkdebugRule *rule, *next;
 529     int i;
 530
 531     for (i = 0; i < BLKDBG_EVENT_MAX; i++) {
 532         QLIST_FOREACH_SAFE(rule, &s->rules[i], next, next) {
 533             remove_rule(rule);
 534         }
 535     }
 536 }
 537
 538 static void suspend_request(BlockDriverState *bs, BlkdebugRule *rule)
 539 {
 540     BDRVBlkdebugState *s = bs->opaque;
 541     BlkdebugSuspendedReq r;
 542
 543     r = (BlkdebugSuspendedReq) {
 544         .co         = qemu_coroutine_self(),
 545         .tag        = g_strdup(rule->options.suspend.tag),
 546     };
 547
 548     remove_rule(rule);
 549     QLIST_INSERT_HEAD(&s->suspended_reqs, &r, next);
 550
 551     printf("blkdebug: Suspended request '%s'\n", r.tag);
 552     qemu_coroutine_yield();
 553     printf("blkdebug: Resuming request '%s'\n", r.tag);
 554
 555     QLIST_REMOVE(&r, next);
 556     g_free(r.tag);
 557 }
 558
 559 static bool process_rule(BlockDriverState *bs, struct BlkdebugRule *rule,
 560     bool injected)
 561 {
 562     BDRVBlkdebugState *s = bs->opaque;
 563
 564     /* Only process rules for the current state */
 565     if (rule->state && rule->state != s->state) {
 566         return injected;
 567     }
 568
 569     /* Take the action */
 570     switch (rule->action) {
 571     case ACTION_INJECT_ERROR:
 572         if (!injected) {
 573             QSIMPLEQ_INIT(&s->active_rules);
 574             injected = true;
 575         }
 576         QSIMPLEQ_INSERT_HEAD(&s->active_rules, rule, active_next);
 577         break;
 578
 579     case ACTION_SET_STATE:
 580         s->new_state = rule->options.set_state.new_state;
 581         break;
 582
 583     case ACTION_SUSPEND:
 584         suspend_request(bs, rule);
 585         break;
 586     }
 587     return injected;
 588 }
 589
 590 static void blkdebug_debug_event(BlockDriverState *bs, BlkDebugEvent event)
 591 {
 592     BDRVBlkdebugState *s = bs->opaque;
 593     struct BlkdebugRule *rule, *next;
 594     bool injected;
 595
 596     assert((int)event >= 0 && event < BLKDBG_EVENT_MAX);
 597
 598     injected = false;
 599     s->new_state = s->state;
 600     QLIST_FOREACH_SAFE(rule, &s->rules[event], next, next) {
 601         injected = process_rule(bs, rule, injected);
 602     }
 603     s->state = s->new_state;
 604 }
 605
 606 static int blkdebug_debug_breakpoint(BlockDriverState *bs, const char *event,
 607                                      const char *tag)
 608 {
 609     BDRVBlkdebugState *s = bs->opaque;
 610     struct BlkdebugRule *rule;
 611     BlkDebugEvent blkdebug_event;
 612
 613     if (get_event_by_name(event, &blkdebug_event) < 0) {
 614         return -ENOENT;
 615     }
 616
 617
 618     rule = g_malloc(sizeof(*rule));
 619     *rule = (struct BlkdebugRule) {
 620         .event  = blkdebug_event,
 621         .action = ACTION_SUSPEND,
 622         .state  = 0,
 623         .options.suspend.tag = g_strdup(tag),
 624     };
 625
 626     QLIST_INSERT_HEAD(&s->rules[blkdebug_event], rule, next);
 627
 628     return 0;
 629 }
 630
 631 static int blkdebug_debug_resume(BlockDriverState *bs, const char *tag)
 632 {
 633     BDRVBlkdebugState *s = bs->opaque;
 634     BlkdebugSuspendedReq *r, *next;
 635
 636     QLIST_FOREACH_SAFE(r, &s->suspended_reqs, next, next) {
 637         if (!strcmp(r->tag, tag)) {
 638             qemu_coroutine_enter(r->co, NULL);
 639             return 0;
 640         }
 641     }
 642     return -ENOENT;
 643 }
 644
 645 static int blkdebug_debug_remove_breakpoint(BlockDriverState *bs,
 646                                             const char *tag)
 647 {
 648     BDRVBlkdebugState *s = bs->opaque;
 649     BlkdebugSuspendedReq *r, *r_next;
 650     BlkdebugRule *rule, *next;
 651     int i, ret = -ENOENT;
 652
 653     for (i = 0; i < BLKDBG_EVENT_MAX; i++) {
 654         QLIST_FOREACH_SAFE(rule, &s->rules[i], next, next) {
 655             if (rule->action == ACTION_SUSPEND &&
 656                 !strcmp(rule->options.suspend.tag, tag)) {
 657                 remove_rule(rule);
 658                 ret = 0;
 659             }
 660         }
 661     }
 662     QLIST_FOREACH_SAFE(r, &s->suspended_reqs, next, r_next) {
 663         if (!strcmp(r->tag, tag)) {
 664             qemu_coroutine_enter(r->co, NULL);
 665             ret = 0;
 666         }
 667     }
 668     return ret;
 669 }
 670
 671 static bool blkdebug_debug_is_suspended(BlockDriverState *bs, const char *tag)
 672 {
 673     BDRVBlkdebugState *s = bs->opaque;
 674     BlkdebugSuspendedReq *r;
 675
 676     QLIST_FOREACH(r, &s->suspended_reqs, next) {
 677         if (!strcmp(r->tag, tag)) {
 678             return true;
 679         }
 680     }
 681     return false;
 682 }
 683
 684 static int64_t blkdebug_getlength(BlockDriverState *bs)
 685 {
 686     return bdrv_getlength(bs->file);
 687 }
 688
 689 static BlockDriver bdrv_blkdebug = {
 690     .format_name            = "blkdebug",
 691     .protocol_name          = "blkdebug",
 692     .instance_size          = sizeof(BDRVBlkdebugState),
 693
 694     .bdrv_parse_filename    = blkdebug_parse_filename,
 695     .bdrv_file_open         = blkdebug_open,
 696     .bdrv_close             = blkdebug_close,
 697     .bdrv_getlength         = blkdebug_getlength,
 698
 699     .bdrv_aio_readv         = blkdebug_aio_readv,
 700     .bdrv_aio_writev        = blkdebug_aio_writev,
 701
 702     .bdrv_debug_event           = blkdebug_debug_event,
 703     .bdrv_debug_breakpoint      = blkdebug_debug_breakpoint,
 704     .bdrv_debug_remove_breakpoint
 705                                 = blkdebug_debug_remove_breakpoint,
 706     .bdrv_debug_resume          = blkdebug_debug_resume,
 707     .bdrv_debug_is_suspended    = blkdebug_debug_is_suspended,
 708 };
 709
 710 static void bdrv_blkdebug_init(void)
 711 {
 712     bdrv_register(&bdrv_blkdebug);
 713 }
 714
 715 block_init(bdrv_blkdebug_init);