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