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 "block_int.h"
  27 #include "module.h"
  28
  29 #include <stdbool.h>
  30
  31 typedef struct BlkdebugVars {
  32     int state;
  33
  34     /* If inject_errno != 0, an error is injected for requests */
  35     int inject_errno;
  36
  37     /* Decides if all future requests fail (false) or only the next one and
  38      * after the next request inject_errno is reset to 0 (true) */
  39     bool inject_once;
  40
  41     /* Decides if aio_readv/writev fails right away (true) or returns an error
  42      * return value only in the callback (false) */
  43     bool inject_immediately;
  44 } BlkdebugVars;
  45
  46 typedef struct BDRVBlkdebugState {
  47     BlockDriverState *hd;
  48     BlkdebugVars vars;
  49     QLIST_HEAD(list, BlkdebugRule) rules[BLKDBG_EVENT_MAX];
  50 } BDRVBlkdebugState;
  51
  52 typedef struct BlkdebugAIOCB {
  53     BlockDriverAIOCB common;
  54     QEMUBH *bh;
  55     int ret;
  56 } BlkdebugAIOCB;
  57
  58 static void blkdebug_aio_cancel(BlockDriverAIOCB *blockacb);
  59
  60 static AIOPool blkdebug_aio_pool = {
  61     .aiocb_size = sizeof(BlkdebugAIOCB),
  62     .cancel     = blkdebug_aio_cancel,
  63 };
  64
  65 enum {
  66     ACTION_INJECT_ERROR,
  67     ACTION_SET_STATE,
  68 };
  69
  70 typedef struct BlkdebugRule {
  71     BlkDebugEvent event;
  72     int action;
  73     int state;
  74     union {
  75         struct {
  76             int error;
  77             int immediately;
  78             int once;
  79         } inject;
  80         struct {
  81             int new_state;
  82         } set_state;
  83     } options;
  84     QLIST_ENTRY(BlkdebugRule) next;
  85 } BlkdebugRule;
  86
  87 static QemuOptsList inject_error_opts = {
  88     .name = "inject-error",
  89     .head = QTAILQ_HEAD_INITIALIZER(inject_error_opts.head),
  90     .desc = {
  91         {
  92             .name = "event",
  93             .type = QEMU_OPT_STRING,
  94         },
  95         {
  96             .name = "state",
  97             .type = QEMU_OPT_NUMBER,
  98         },
  99         {
 100             .name = "errno",
 101             .type = QEMU_OPT_NUMBER,
 102         },
 103         {
 104             .name = "once",
 105             .type = QEMU_OPT_BOOL,
 106         },
 107         {
 108             .name = "immediately",
 109             .type = QEMU_OPT_BOOL,
 110         },
 111         { /* end of list */ }
 112     },
 113 };
 114
 115 static QemuOptsList set_state_opts = {
 116     .name = "set-state",
 117     .head = QTAILQ_HEAD_INITIALIZER(inject_error_opts.head),
 118     .desc = {
 119         {
 120             .name = "event",
 121             .type = QEMU_OPT_STRING,
 122         },
 123         {
 124             .name = "state",
 125             .type = QEMU_OPT_NUMBER,
 126         },
 127         {
 128             .name = "new_state",
 129             .type = QEMU_OPT_NUMBER,
 130         },
 131         { /* end of list */ }
 132     },
 133 };
 134
 135 static QemuOptsList *config_groups[] = {
 136     &inject_error_opts,
 137     &set_state_opts,
 138     NULL
 139 };
 140
 141 static const char *event_names[BLKDBG_EVENT_MAX] = {
 142     [BLKDBG_L1_UPDATE]                      = "l1_update",
 143     [BLKDBG_L1_GROW_ALLOC_TABLE]            = "l1_grow.alloc_table",
 144     [BLKDBG_L1_GROW_WRITE_TABLE]            = "l1_grow.write_table",
 145     [BLKDBG_L1_GROW_ACTIVATE_TABLE]         = "l1_grow.activate_table",
 146
 147     [BLKDBG_L2_LOAD]                        = "l2_load",
 148     [BLKDBG_L2_UPDATE]                      = "l2_update",
 149     [BLKDBG_L2_UPDATE_COMPRESSED]           = "l2_update_compressed",
 150     [BLKDBG_L2_ALLOC_COW_READ]              = "l2_alloc.cow_read",
 151     [BLKDBG_L2_ALLOC_WRITE]                 = "l2_alloc.write",
 152
 153     [BLKDBG_READ]                           = "read",
 154     [BLKDBG_READ_AIO]                       = "read_aio",
 155     [BLKDBG_READ_BACKING]                   = "read_backing",
 156     [BLKDBG_READ_BACKING_AIO]               = "read_backing_aio",
 157     [BLKDBG_READ_COMPRESSED]                = "read_compressed",
 158
 159     [BLKDBG_WRITE_AIO]                      = "write_aio",
 160     [BLKDBG_WRITE_COMPRESSED]               = "write_compressed",
 161
 162     [BLKDBG_VMSTATE_LOAD]                   = "vmstate_load",
 163     [BLKDBG_VMSTATE_SAVE]                   = "vmstate_save",
 164
 165     [BLKDBG_COW_READ]                       = "cow_read",
 166     [BLKDBG_COW_WRITE]                      = "cow_write",
 167
 168     [BLKDBG_REFTABLE_LOAD]                  = "reftable_load",
 169     [BLKDBG_REFTABLE_GROW]                  = "reftable_grow",
 170
 171     [BLKDBG_REFBLOCK_LOAD]                  = "refblock_load",
 172     [BLKDBG_REFBLOCK_UPDATE]                = "refblock_update",
 173     [BLKDBG_REFBLOCK_UPDATE_PART]           = "refblock_update_part",
 174     [BLKDBG_REFBLOCK_ALLOC]                 = "refblock_alloc",
 175     [BLKDBG_REFBLOCK_ALLOC_HOOKUP]          = "refblock_alloc.hookup",
 176     [BLKDBG_REFBLOCK_ALLOC_WRITE]           = "refblock_alloc.write",
 177     [BLKDBG_REFBLOCK_ALLOC_WRITE_BLOCKS]    = "refblock_alloc.write_blocks",
 178     [BLKDBG_REFBLOCK_ALLOC_WRITE_TABLE]     = "refblock_alloc.write_table",
 179     [BLKDBG_REFBLOCK_ALLOC_SWITCH_TABLE]    = "refblock_alloc.switch_table",
 180
 181     [BLKDBG_CLUSTER_ALLOC]                  = "cluster_alloc",
 182     [BLKDBG_CLUSTER_ALLOC_BYTES]            = "cluster_alloc_bytes",
 183     [BLKDBG_CLUSTER_FREE]                   = "cluster_free",
 184 };
 185
 186 static int get_event_by_name(const char *name, BlkDebugEvent *event)
 187 {
 188     int i;
 189
 190     for (i = 0; i < BLKDBG_EVENT_MAX; i++) {
 191         if (!strcmp(event_names[i], name)) {
 192             *event = i;
 193             return 0;
 194         }
 195     }
 196
 197     return -1;
 198 }
 199
 200 struct add_rule_data {
 201     BDRVBlkdebugState *s;
 202     int action;
 203 };
 204
 205 static int add_rule(QemuOpts *opts, void *opaque)
 206 {
 207     struct add_rule_data *d = opaque;
 208     BDRVBlkdebugState *s = d->s;
 209     const char* event_name;
 210     BlkDebugEvent event;
 211     struct BlkdebugRule *rule;
 212
 213     /* Find the right event for the rule */
 214     event_name = qemu_opt_get(opts, "event");
 215     if (!event_name || get_event_by_name(event_name, &event) < 0) {
 216         return -1;
 217     }
 218
 219     /* Set attributes common for all actions */
 220     rule = qemu_mallocz(sizeof(*rule));
 221     *rule = (struct BlkdebugRule) {
 222         .event  = event,
 223         .action = d->action,
 224         .state  = qemu_opt_get_number(opts, "state", 0),
 225     };
 226
 227     /* Parse action-specific options */
 228     switch (d->action) {
 229     case ACTION_INJECT_ERROR:
 230         rule->options.inject.error = qemu_opt_get_number(opts, "errno", EIO);
 231         rule->options.inject.once  = qemu_opt_get_bool(opts, "once", 0);
 232         rule->options.inject.immediately =
 233             qemu_opt_get_bool(opts, "immediately", 0);
 234         break;
 235
 236     case ACTION_SET_STATE:
 237         rule->options.set_state.new_state =
 238             qemu_opt_get_number(opts, "new_state", 0);
 239         break;
 240     };
 241
 242     /* Add the rule */
 243     QLIST_INSERT_HEAD(&s->rules[event], rule, next);
 244
 245     return 0;
 246 }
 247
 248 static int read_config(BDRVBlkdebugState *s, const char *filename)
 249 {
 250     FILE *f;
 251     int ret;
 252     struct add_rule_data d;
 253
 254     f = fopen(filename, "r");
 255     if (f == NULL) {
 256         return -errno;
 257     }
 258
 259     ret = qemu_config_parse(f, config_groups, filename);
 260     if (ret < 0) {
 261         goto fail;
 262     }
 263
 264     d.s = s;
 265     d.action = ACTION_INJECT_ERROR;
 266     qemu_opts_foreach(&inject_error_opts, add_rule, &d, 0);
 267
 268     d.action = ACTION_SET_STATE;
 269     qemu_opts_foreach(&set_state_opts, add_rule, &d, 0);
 270
 271     ret = 0;
 272 fail:
 273     fclose(f);
 274     return ret;
 275 }
 276
 277 /* Valid blkdebug filenames look like blkdebug:path/to/config:path/to/image */
 278 static int blkdebug_open(BlockDriverState *bs, const char *filename, int flags)
 279 {
 280     BDRVBlkdebugState *s = bs->opaque;
 281     int ret;
 282     char *config, *c;
 283
 284     /* Parse the blkdebug: prefix */
 285     if (strncmp(filename, "blkdebug:", strlen("blkdebug:"))) {
 286         return -EINVAL;
 287     }
 288     filename += strlen("blkdebug:");
 289
 290     /* Read rules from config file */
 291     c = strchr(filename, ':');
 292     if (c == NULL) {
 293         return -EINVAL;
 294     }
 295
 296     config = strdup(filename);
 297     config[c - filename] = '\0';
 298     ret = read_config(s, config);
 299     free(config);
 300     if (ret < 0) {
 301         return ret;
 302     }
 303     filename = c + 1;
 304
 305     /* Open the backing file */
 306     ret = bdrv_file_open(&s->hd, filename, flags);
 307     if (ret < 0) {
 308         return ret;
 309     }
 310
 311     return 0;
 312 }
 313
 314 static void error_callback_bh(void *opaque)
 315 {
 316     struct BlkdebugAIOCB *acb = opaque;
 317     qemu_bh_delete(acb->bh);
 318     acb->common.cb(acb->common.opaque, acb->ret);
 319     qemu_aio_release(acb);
 320 }
 321
 322 static void blkdebug_aio_cancel(BlockDriverAIOCB *blockacb)
 323 {
 324     BlkdebugAIOCB *acb = (BlkdebugAIOCB*) blockacb;
 325     qemu_aio_release(acb);
 326 }
 327
 328 static BlockDriverAIOCB *inject_error(BlockDriverState *bs,
 329     BlockDriverCompletionFunc *cb, void *opaque)
 330 {
 331     BDRVBlkdebugState *s = bs->opaque;
 332     int error = s->vars.inject_errno;
 333     struct BlkdebugAIOCB *acb;
 334     QEMUBH *bh;
 335
 336     if (s->vars.inject_once) {
 337         s->vars.inject_errno = 0;
 338     }
 339
 340     if (s->vars.inject_immediately) {
 341         return NULL;
 342     }
 343
 344     acb = qemu_aio_get(&blkdebug_aio_pool, bs, cb, opaque);
 345     acb->ret = -error;
 346
 347     bh = qemu_bh_new(error_callback_bh, acb);
 348     acb->bh = bh;
 349     qemu_bh_schedule(bh);
 350
 351     return (BlockDriverAIOCB*) acb;
 352 }
 353
 354 static BlockDriverAIOCB *blkdebug_aio_readv(BlockDriverState *bs,
 355     int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 356     BlockDriverCompletionFunc *cb, void *opaque)
 357 {
 358     BDRVBlkdebugState *s = bs->opaque;
 359
 360     if (s->vars.inject_errno) {
 361         return inject_error(bs, cb, opaque);
 362     }
 363
 364     BlockDriverAIOCB *acb =
 365         bdrv_aio_readv(s->hd, sector_num, qiov, nb_sectors, cb, opaque);
 366     return acb;
 367 }
 368
 369 static BlockDriverAIOCB *blkdebug_aio_writev(BlockDriverState *bs,
 370     int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 371     BlockDriverCompletionFunc *cb, void *opaque)
 372 {
 373     BDRVBlkdebugState *s = bs->opaque;
 374
 375     if (s->vars.inject_errno) {
 376         return inject_error(bs, cb, opaque);
 377     }
 378
 379     BlockDriverAIOCB *acb =
 380         bdrv_aio_writev(s->hd, sector_num, qiov, nb_sectors, cb, opaque);
 381     return acb;
 382 }
 383
 384 static void blkdebug_close(BlockDriverState *bs)
 385 {
 386     BDRVBlkdebugState *s = bs->opaque;
 387     BlkdebugRule *rule, *next;
 388     int i;
 389
 390     for (i = 0; i < BLKDBG_EVENT_MAX; i++) {
 391         QLIST_FOREACH_SAFE(rule, &s->rules[i], next, next) {
 392             QLIST_REMOVE(rule, next);
 393             qemu_free(rule);
 394         }
 395     }
 396
 397     bdrv_delete(s->hd);
 398 }
 399
 400 static void blkdebug_flush(BlockDriverState *bs)
 401 {
 402     BDRVBlkdebugState *s = bs->opaque;
 403     bdrv_flush(s->hd);
 404 }
 405
 406 static BlockDriverAIOCB *blkdebug_aio_flush(BlockDriverState *bs,
 407     BlockDriverCompletionFunc *cb, void *opaque)
 408 {
 409     BDRVBlkdebugState *s = bs->opaque;
 410     return bdrv_aio_flush(s->hd, cb, opaque);
 411 }
 412
 413 static void process_rule(BlockDriverState *bs, struct BlkdebugRule *rule,
 414     BlkdebugVars *old_vars)
 415 {
 416     BDRVBlkdebugState *s = bs->opaque;
 417     BlkdebugVars *vars = &s->vars;
 418
 419     /* Only process rules for the current state */
 420     if (rule->state && rule->state != old_vars->state) {
 421         return;
 422     }
 423
 424     /* Take the action */
 425     switch (rule->action) {
 426     case ACTION_INJECT_ERROR:
 427         vars->inject_errno       = rule->options.inject.error;
 428         vars->inject_once        = rule->options.inject.once;
 429         vars->inject_immediately = rule->options.inject.immediately;
 430         break;
 431
 432     case ACTION_SET_STATE:
 433         vars->state              = rule->options.set_state.new_state;
 434         break;
 435     }
 436 }
 437
 438 static void blkdebug_debug_event(BlockDriverState *bs, BlkDebugEvent event)
 439 {
 440     BDRVBlkdebugState *s = bs->opaque;
 441     struct BlkdebugRule *rule;
 442     BlkdebugVars old_vars = s->vars;
 443
 444     if (event < 0 || event >= BLKDBG_EVENT_MAX) {
 445         return;
 446     }
 447
 448     QLIST_FOREACH(rule, &s->rules[event], next) {
 449         process_rule(bs, rule, &old_vars);
 450     }
 451 }
 452
 453 static BlockDriver bdrv_blkdebug = {
 454     .format_name        = "blkdebug",
 455     .protocol_name      = "blkdebug",
 456
 457     .instance_size      = sizeof(BDRVBlkdebugState),
 458
 459     .bdrv_open          = blkdebug_open,
 460     .bdrv_close         = blkdebug_close,
 461     .bdrv_flush         = blkdebug_flush,
 462
 463     .bdrv_aio_readv     = blkdebug_aio_readv,
 464     .bdrv_aio_writev    = blkdebug_aio_writev,
 465     .bdrv_aio_flush     = blkdebug_aio_flush,
 466
 467     .bdrv_debug_event   = blkdebug_debug_event,
 468 };
 469
 470 static void bdrv_blkdebug_init(void)
 471 {
 472     bdrv_register(&bdrv_blkdebug);
 473 }
 474
 475 block_init(bdrv_blkdebug_init);