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