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 typedef struct BlkdebugVars {
  30     int state;
  31
  32     /* If inject_errno != 0, an error is injected for requests */
  33     int inject_errno;
  34
  35     /* Decides if all future requests fail (false) or only the next one and
  36      * after the next request inject_errno is reset to 0 (true) */
  37     bool inject_once;
  38
  39     /* Decides if aio_readv/writev fails right away (true) or returns an error
  40      * return value only in the callback (false) */
  41     bool inject_immediately;
  42 } BlkdebugVars;
  43
  44 typedef struct BDRVBlkdebugState {
  45     BlkdebugVars vars;
  46     QLIST_HEAD(list, BlkdebugRule) rules[BLKDBG_EVENT_MAX];
  47 } BDRVBlkdebugState;
  48
  49 typedef struct BlkdebugAIOCB {
  50     BlockDriverAIOCB common;
  51     QEMUBH *bh;
  52     int ret;
  53 } BlkdebugAIOCB;
  54
  55 static void blkdebug_aio_cancel(BlockDriverAIOCB *blockacb);
  56
  57 static AIOPool blkdebug_aio_pool = {
  58     .aiocb_size = sizeof(BlkdebugAIOCB),
  59     .cancel     = blkdebug_aio_cancel,
  60 };
  61
  62 enum {
  63     ACTION_INJECT_ERROR,
  64     ACTION_SET_STATE,
  65 };
  66
  67 typedef struct BlkdebugRule {
  68     BlkDebugEvent event;
  69     int action;
  70     int state;
  71     union {
  72         struct {
  73             int error;
  74             int immediately;
  75             int once;
  76         } inject;
  77         struct {
  78             int new_state;
  79         } set_state;
  80     } options;
  81     QLIST_ENTRY(BlkdebugRule) next;
  82 } BlkdebugRule;
  83
  84 static QemuOptsList inject_error_opts = {
  85     .name = "inject-error",
  86     .head = QTAILQ_HEAD_INITIALIZER(inject_error_opts.head),
  87     .desc = {
  88         {
  89             .name = "event",
  90             .type = QEMU_OPT_STRING,
  91         },
  92         {
  93             .name = "state",
  94             .type = QEMU_OPT_NUMBER,
  95         },
  96         {
  97             .name = "errno",
  98             .type = QEMU_OPT_NUMBER,
  99         },
 100         {
 101             .name = "once",
 102             .type = QEMU_OPT_BOOL,
 103         },
 104         {
 105             .name = "immediately",
 106             .type = QEMU_OPT_BOOL,
 107         },
 108         { /* end of list */ }
 109     },
 110 };
 111
 112 static QemuOptsList set_state_opts = {
 113     .name = "set-state",
 114     .head = QTAILQ_HEAD_INITIALIZER(set_state_opts.head),
 115     .desc = {
 116         {
 117             .name = "event",
 118             .type = QEMU_OPT_STRING,
 119         },
 120         {
 121             .name = "state",
 122             .type = QEMU_OPT_NUMBER,
 123         },
 124         {
 125             .name = "new_state",
 126             .type = QEMU_OPT_NUMBER,
 127         },
 128         { /* end of list */ }
 129     },
 130 };
 131
 132 static QemuOptsList *config_groups[] = {
 133     &inject_error_opts,
 134     &set_state_opts,
 135     NULL
 136 };
 137
 138 static const char *event_names[BLKDBG_EVENT_MAX] = {
 139     [BLKDBG_L1_UPDATE]                      = "l1_update",
 140     [BLKDBG_L1_GROW_ALLOC_TABLE]            = "l1_grow.alloc_table",
 141     [BLKDBG_L1_GROW_WRITE_TABLE]            = "l1_grow.write_table",
 142     [BLKDBG_L1_GROW_ACTIVATE_TABLE]         = "l1_grow.activate_table",
 143
 144     [BLKDBG_L2_LOAD]                        = "l2_load",
 145     [BLKDBG_L2_UPDATE]                      = "l2_update",
 146     [BLKDBG_L2_UPDATE_COMPRESSED]           = "l2_update_compressed",
 147     [BLKDBG_L2_ALLOC_COW_READ]              = "l2_alloc.cow_read",
 148     [BLKDBG_L2_ALLOC_WRITE]                 = "l2_alloc.write",
 149
 150     [BLKDBG_READ]                           = "read",
 151     [BLKDBG_READ_AIO]                       = "read_aio",
 152     [BLKDBG_READ_BACKING]                   = "read_backing",
 153     [BLKDBG_READ_BACKING_AIO]               = "read_backing_aio",
 154     [BLKDBG_READ_COMPRESSED]                = "read_compressed",
 155
 156     [BLKDBG_WRITE_AIO]                      = "write_aio",
 157     [BLKDBG_WRITE_COMPRESSED]               = "write_compressed",
 158
 159     [BLKDBG_VMSTATE_LOAD]                   = "vmstate_load",
 160     [BLKDBG_VMSTATE_SAVE]                   = "vmstate_save",
 161
 162     [BLKDBG_COW_READ]                       = "cow_read",
 163     [BLKDBG_COW_WRITE]                      = "cow_write",
 164
 165     [BLKDBG_REFTABLE_LOAD]                  = "reftable_load",
 166     [BLKDBG_REFTABLE_GROW]                  = "reftable_grow",
 167
 168     [BLKDBG_REFBLOCK_LOAD]                  = "refblock_load",
 169     [BLKDBG_REFBLOCK_UPDATE]                = "refblock_update",
 170     [BLKDBG_REFBLOCK_UPDATE_PART]           = "refblock_update_part",
 171     [BLKDBG_REFBLOCK_ALLOC]                 = "refblock_alloc",
 172     [BLKDBG_REFBLOCK_ALLOC_HOOKUP]          = "refblock_alloc.hookup",
 173     [BLKDBG_REFBLOCK_ALLOC_WRITE]           = "refblock_alloc.write",
 174     [BLKDBG_REFBLOCK_ALLOC_WRITE_BLOCKS]    = "refblock_alloc.write_blocks",
 175     [BLKDBG_REFBLOCK_ALLOC_WRITE_TABLE]     = "refblock_alloc.write_table",
 176     [BLKDBG_REFBLOCK_ALLOC_SWITCH_TABLE]    = "refblock_alloc.switch_table",
 177
 178     [BLKDBG_CLUSTER_ALLOC]                  = "cluster_alloc",
 179     [BLKDBG_CLUSTER_ALLOC_BYTES]            = "cluster_alloc_bytes",
 180     [BLKDBG_CLUSTER_FREE]                   = "cluster_free",
 181 };
 182
 183 static int get_event_by_name(const char *name, BlkDebugEvent *event)
 184 {
 185     int i;
 186
 187     for (i = 0; i < BLKDBG_EVENT_MAX; i++) {
 188         if (!strcmp(event_names[i], name)) {
 189             *event = i;
 190             return 0;
 191         }
 192     }
 193
 194     return -1;
 195 }
 196
 197 struct add_rule_data {
 198     BDRVBlkdebugState *s;
 199     int action;
 200 };
 201
 202 static int add_rule(QemuOpts *opts, void *opaque)
 203 {
 204     struct add_rule_data *d = opaque;
 205     BDRVBlkdebugState *s = d->s;
 206     const char* event_name;
 207     BlkDebugEvent event;
 208     struct BlkdebugRule *rule;
 209
 210     /* Find the right event for the rule */
 211     event_name = qemu_opt_get(opts, "event");
 212     if (!event_name || get_event_by_name(event_name, &event) < 0) {
 213         return -1;
 214     }
 215
 216     /* Set attributes common for all actions */
 217     rule = g_malloc0(sizeof(*rule));
 218     *rule = (struct BlkdebugRule) {
 219         .event  = event,
 220         .action = d->action,
 221         .state  = qemu_opt_get_number(opts, "state", 0),
 222     };
 223
 224     /* Parse action-specific options */
 225     switch (d->action) {
 226     case ACTION_INJECT_ERROR:
 227         rule->options.inject.error = qemu_opt_get_number(opts, "errno", EIO);
 228         rule->options.inject.once  = qemu_opt_get_bool(opts, "once", 0);
 229         rule->options.inject.immediately =
 230             qemu_opt_get_bool(opts, "immediately", 0);
 231         break;
 232
 233     case ACTION_SET_STATE:
 234         rule->options.set_state.new_state =
 235             qemu_opt_get_number(opts, "new_state", 0);
 236         break;
 237     };
 238
 239     /* Add the rule */
 240     QLIST_INSERT_HEAD(&s->rules[event], rule, next);
 241
 242     return 0;
 243 }
 244
 245 static int read_config(BDRVBlkdebugState *s, const char *filename)
 246 {
 247     FILE *f;
 248     int ret;
 249     struct add_rule_data d;
 250
 251     f = fopen(filename, "r");
 252     if (f == NULL) {
 253         return -errno;
 254     }
 255
 256     ret = qemu_config_parse(f, config_groups, filename);
 257     if (ret < 0) {
 258         goto fail;
 259     }
 260
 261     d.s = s;
 262     d.action = ACTION_INJECT_ERROR;
 263     qemu_opts_foreach(&inject_error_opts, add_rule, &d, 0);
 264
 265     d.action = ACTION_SET_STATE;
 266     qemu_opts_foreach(&set_state_opts, add_rule, &d, 0);
 267
 268     ret = 0;
 269 fail:
 270     qemu_opts_reset(&inject_error_opts);
 271     qemu_opts_reset(&set_state_opts);
 272     fclose(f);
 273     return ret;
 274 }
 275
 276 /* Valid blkdebug filenames look like blkdebug:path/to/config:path/to/image */
 277 static int blkdebug_open(BlockDriverState *bs, const char *filename, int flags)
 278 {
 279     BDRVBlkdebugState *s = bs->opaque;
 280     int ret;
 281     char *config, *c;
 282
 283     /* Parse the blkdebug: prefix */
 284     if (strncmp(filename, "blkdebug:", strlen("blkdebug:"))) {
 285         return -EINVAL;
 286     }
 287     filename += strlen("blkdebug:");
 288
 289     /* Read rules from config file */
 290     c = strchr(filename, ':');
 291     if (c == NULL) {
 292         return -EINVAL;
 293     }
 294
 295     config = strdup(filename);
 296     config[c - filename] = '\0';
 297     ret = read_config(s, config);
 298     free(config);
 299     if (ret < 0) {
 300         return ret;
 301     }
 302     filename = c + 1;
 303
 304     /* Set initial state */
 305     s->vars.state = 1;
 306
 307     /* Open the backing file */
 308     ret = bdrv_file_open(&bs->file, filename, flags);
 309     if (ret < 0) {
 310         return ret;
 311     }
 312
 313     return 0;
 314 }
 315
 316 static void error_callback_bh(void *opaque)
 317 {
 318     struct BlkdebugAIOCB *acb = opaque;
 319     qemu_bh_delete(acb->bh);
 320     acb->common.cb(acb->common.opaque, acb->ret);
 321     qemu_aio_release(acb);
 322 }
 323
 324 static void blkdebug_aio_cancel(BlockDriverAIOCB *blockacb)
 325 {
 326     BlkdebugAIOCB *acb = container_of(blockacb, BlkdebugAIOCB, common);
 327     qemu_aio_release(acb);
 328 }
 329
 330 static BlockDriverAIOCB *inject_error(BlockDriverState *bs,
 331     BlockDriverCompletionFunc *cb, void *opaque)
 332 {
 333     BDRVBlkdebugState *s = bs->opaque;
 334     int error = s->vars.inject_errno;
 335     struct BlkdebugAIOCB *acb;
 336     QEMUBH *bh;
 337
 338     if (s->vars.inject_once) {
 339         s->vars.inject_errno = 0;
 340     }
 341
 342     if (s->vars.inject_immediately) {
 343         return NULL;
 344     }
 345
 346     acb = qemu_aio_get(&blkdebug_aio_pool, bs, cb, opaque);
 347     acb->ret = -error;
 348
 349     bh = qemu_bh_new(error_callback_bh, acb);
 350     acb->bh = bh;
 351     qemu_bh_schedule(bh);
 352
 353     return &acb->common;
 354 }
 355
 356 static BlockDriverAIOCB *blkdebug_aio_readv(BlockDriverState *bs,
 357     int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 358     BlockDriverCompletionFunc *cb, void *opaque)
 359 {
 360     BDRVBlkdebugState *s = bs->opaque;
 361
 362     if (s->vars.inject_errno) {
 363         return inject_error(bs, cb, opaque);
 364     }
 365
 366     BlockDriverAIOCB *acb =
 367         bdrv_aio_readv(bs->file, sector_num, qiov, nb_sectors, cb, opaque);
 368     return acb;
 369 }
 370
 371 static BlockDriverAIOCB *blkdebug_aio_writev(BlockDriverState *bs,
 372     int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 373     BlockDriverCompletionFunc *cb, void *opaque)
 374 {
 375     BDRVBlkdebugState *s = bs->opaque;
 376
 377     if (s->vars.inject_errno) {
 378         return inject_error(bs, cb, opaque);
 379     }
 380
 381     BlockDriverAIOCB *acb =
 382         bdrv_aio_writev(bs->file, sector_num, qiov, nb_sectors, cb, opaque);
 383     return acb;
 384 }
 385
 386 static void blkdebug_close(BlockDriverState *bs)
 387 {
 388     BDRVBlkdebugState *s = bs->opaque;
 389     BlkdebugRule *rule, *next;
 390     int i;
 391
 392     for (i = 0; i < BLKDBG_EVENT_MAX; i++) {
 393         QLIST_FOREACH_SAFE(rule, &s->rules[i], next, next) {
 394             QLIST_REMOVE(rule, next);
 395             g_free(rule);
 396         }
 397     }
 398 }
 399
 400 static BlockDriverAIOCB *blkdebug_aio_flush(BlockDriverState *bs,
 401     BlockDriverCompletionFunc *cb, void *opaque)
 402 {
 403     return bdrv_aio_flush(bs->file, cb, opaque);
 404 }
 405
 406 static void process_rule(BlockDriverState *bs, struct BlkdebugRule *rule,
 407     BlkdebugVars *old_vars)
 408 {
 409     BDRVBlkdebugState *s = bs->opaque;
 410     BlkdebugVars *vars = &s->vars;
 411
 412     /* Only process rules for the current state */
 413     if (rule->state && rule->state != old_vars->state) {
 414         return;
 415     }
 416
 417     /* Take the action */
 418     switch (rule->action) {
 419     case ACTION_INJECT_ERROR:
 420         vars->inject_errno       = rule->options.inject.error;
 421         vars->inject_once        = rule->options.inject.once;
 422         vars->inject_immediately = rule->options.inject.immediately;
 423         break;
 424
 425     case ACTION_SET_STATE:
 426         vars->state              = rule->options.set_state.new_state;
 427         break;
 428     }
 429 }
 430
 431 static void blkdebug_debug_event(BlockDriverState *bs, BlkDebugEvent event)
 432 {
 433     BDRVBlkdebugState *s = bs->opaque;
 434     struct BlkdebugRule *rule;
 435     BlkdebugVars old_vars = s->vars;
 436
 437     assert((int)event >= 0 && event < BLKDBG_EVENT_MAX);
 438
 439     QLIST_FOREACH(rule, &s->rules[event], next) {
 440         process_rule(bs, rule, &old_vars);
 441     }
 442 }
 443
 444 static BlockDriver bdrv_blkdebug = {
 445     .format_name        = "blkdebug",
 446     .protocol_name      = "blkdebug",
 447
 448     .instance_size      = sizeof(BDRVBlkdebugState),
 449
 450     .bdrv_file_open     = blkdebug_open,
 451     .bdrv_close         = blkdebug_close,
 452
 453     .bdrv_aio_readv     = blkdebug_aio_readv,
 454     .bdrv_aio_writev    = blkdebug_aio_writev,
 455     .bdrv_aio_flush     = blkdebug_aio_flush,
 456
 457     .bdrv_debug_event   = blkdebug_debug_event,
 458 };
 459
 460 static void bdrv_blkdebug_init(void)
 461 {
 462     bdrv_register(&bdrv_blkdebug);
 463 }
 464
 465 block_init(bdrv_blkdebug_init);