usr/src/uts/common/fs/zfs/zio_inject.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  23  * Copyright (c) 2012 by Delphix. All rights reserved.
  24  */
  25
  26 /*
  27  * ZFS fault injection
  28  *
  29  * To handle fault injection, we keep track of a series of zinject_record_t
  30  * structures which describe which logical block(s) should be injected with a
  31  * fault.  These are kept in a global list.  Each record corresponds to a given
  32  * spa_t and maintains a special hold on the spa_t so that it cannot be deleted
  33  * or exported while the injection record exists.
  34  *
  35  * Device level injection is done using the 'zi_guid' field.  If this is set, it
  36  * means that the error is destined for a particular device, not a piece of
  37  * data.
  38  *
  39  * This is a rather poor data structure and algorithm, but we don't expect more
  40  * than a few faults at any one time, so it should be sufficient for our needs.
  41  */
  42
  43 #include <sys/arc.h>
  44 #include <sys/zio_impl.h>
  45 #include <sys/zfs_ioctl.h>
  46 #include <sys/vdev_impl.h>
  47 #include <sys/dmu_objset.h>
  48 #include <sys/fs/zfs.h>
  49
  50 uint32_t zio_injection_enabled;
  51
  52 typedef struct inject_handler {
  53         int                     zi_id;
  54         spa_t                   *zi_spa;
  55         zinject_record_t        zi_record;
  56         list_node_t             zi_link;
  57 } inject_handler_t;
  58
  59 static list_t inject_handlers;
  60 static krwlock_t inject_lock;
  61 static int inject_next_id = 1;
  62
  63 /*
  64  * Returns true if the given record matches the I/O in progress.
  65  */
  66 static boolean_t
  67 zio_match_handler(zbookmark_t *zb, uint64_t type,
  68     zinject_record_t *record, int error)
  69 {
  70         /*
  71          * Check for a match against the MOS, which is based on type
  72          */
  73         if (zb->zb_objset == DMU_META_OBJSET &&
  74             record->zi_objset == DMU_META_OBJSET &&
  75             record->zi_object == DMU_META_DNODE_OBJECT) {
  76                 if (record->zi_type == DMU_OT_NONE ||
  77                     type == record->zi_type)
  78                         return (record->zi_freq == 0 ||
  79                             spa_get_random(100) < record->zi_freq);
  80                 else
  81                         return (B_FALSE);
  82         }
  83
  84         /*
  85          * Check for an exact match.
  86          */
  87         if (zb->zb_objset == record->zi_objset &&
  88             zb->zb_object == record->zi_object &&
  89             zb->zb_level == record->zi_level &&
  90             zb->zb_blkid >= record->zi_start &&
  91             zb->zb_blkid <= record->zi_end &&
  92             error == record->zi_error)
  93                 return (record->zi_freq == 0 ||
  94                     spa_get_random(100) < record->zi_freq);
  95
  96         return (B_FALSE);
  97 }
  98
  99 /*
 100  * Panic the system when a config change happens in the function
 101  * specified by tag.
 102  */
 103 void
 104 zio_handle_panic_injection(spa_t *spa, char *tag, uint64_t type)
 105 {
 106         inject_handler_t *handler;
 107
 108         rw_enter(&inject_lock, RW_READER);
 109
 110         for (handler = list_head(&inject_handlers); handler != NULL;
 111             handler = list_next(&inject_handlers, handler)) {
 112
 113                 if (spa != handler->zi_spa)
 114                         continue;
 115
 116                 if (handler->zi_record.zi_type == type &&
 117                     strcmp(tag, handler->zi_record.zi_func) == 0)
 118                         panic("Panic requested in function %s\n", tag);
 119         }
 120
 121         rw_exit(&inject_lock);
 122 }
 123
 124 /*
 125  * Determine if the I/O in question should return failure.  Returns the errno
 126  * to be returned to the caller.
 127  */
 128 int
 129 zio_handle_fault_injection(zio_t *zio, int error)
 130 {
 131         int ret = 0;
 132         inject_handler_t *handler;
 133
 134         /*
 135          * Ignore I/O not associated with any logical data.
 136          */
 137         if (zio->io_logical == NULL)
 138                 return (0);
 139
 140         /*
 141          * Currently, we only support fault injection on reads.
 142          */
 143         if (zio->io_type != ZIO_TYPE_READ)
 144                 return (0);
 145
 146         rw_enter(&inject_lock, RW_READER);
 147
 148         for (handler = list_head(&inject_handlers); handler != NULL;
 149             handler = list_next(&inject_handlers, handler)) {
 150
 151                 if (zio->io_spa != handler->zi_spa ||
 152                     handler->zi_record.zi_cmd != ZINJECT_DATA_FAULT)
 153                         continue;
 154
 155                 /* If this handler matches, return EIO */
 156                 if (zio_match_handler(&zio->io_logical->io_bookmark,
 157                     zio->io_bp ? BP_GET_TYPE(zio->io_bp) : DMU_OT_NONE,
 158                     &handler->zi_record, error)) {
 159                         ret = error;
 160                         break;
 161                 }
 162         }
 163
 164         rw_exit(&inject_lock);
 165
 166         return (ret);
 167 }
 168
 169 /*
 170  * Determine if the zio is part of a label update and has an injection
 171  * handler associated with that portion of the label. Currently, we
 172  * allow error injection in either the nvlist or the uberblock region of
 173  * of the vdev label.
 174  */
 175 int
 176 zio_handle_label_injection(zio_t *zio, int error)
 177 {
 178         inject_handler_t *handler;
 179         vdev_t *vd = zio->io_vd;
 180         uint64_t offset = zio->io_offset;
 181         int label;
 182         int ret = 0;
 183
 184         if (offset >= VDEV_LABEL_START_SIZE &&
 185             offset < vd->vdev_psize - VDEV_LABEL_END_SIZE)
 186                 return (0);
 187
 188         rw_enter(&inject_lock, RW_READER);
 189
 190         for (handler = list_head(&inject_handlers); handler != NULL;
 191             handler = list_next(&inject_handlers, handler)) {
 192                 uint64_t start = handler->zi_record.zi_start;
 193                 uint64_t end = handler->zi_record.zi_end;
 194
 195                 if (handler->zi_record.zi_cmd != ZINJECT_LABEL_FAULT)
 196                         continue;
 197
 198                 /*
 199                  * The injection region is the relative offsets within a
 200                  * vdev label. We must determine the label which is being
 201                  * updated and adjust our region accordingly.
 202                  */
 203                 label = vdev_label_number(vd->vdev_psize, offset);
 204                 start = vdev_label_offset(vd->vdev_psize, label, start);
 205                 end = vdev_label_offset(vd->vdev_psize, label, end);
 206
 207                 if (zio->io_vd->vdev_guid == handler->zi_record.zi_guid &&
 208                     (offset >= start && offset <= end)) {
 209                         ret = error;
 210                         break;
 211                 }
 212         }
 213         rw_exit(&inject_lock);
 214         return (ret);
 215 }
 216
 217
 218 int
 219 zio_handle_device_injection(vdev_t *vd, zio_t *zio, int error)
 220 {
 221         inject_handler_t *handler;
 222         int ret = 0;
 223
 224         /*
 225          * We skip over faults in the labels unless it's during
 226          * device open (i.e. zio == NULL).
 227          */
 228         if (zio != NULL) {
 229                 uint64_t offset = zio->io_offset;
 230
 231                 if (offset < VDEV_LABEL_START_SIZE ||
 232                     offset >= vd->vdev_psize - VDEV_LABEL_END_SIZE)
 233                         return (0);
 234         }
 235
 236         rw_enter(&inject_lock, RW_READER);
 237
 238         for (handler = list_head(&inject_handlers); handler != NULL;
 239             handler = list_next(&inject_handlers, handler)) {
 240
 241                 if (handler->zi_record.zi_cmd != ZINJECT_DEVICE_FAULT)
 242                         continue;
 243
 244                 if (vd->vdev_guid == handler->zi_record.zi_guid) {
 245                         if (handler->zi_record.zi_failfast &&
 246                             (zio == NULL || (zio->io_flags &
 247                             (ZIO_FLAG_IO_RETRY | ZIO_FLAG_TRYHARD)))) {
 248                                 continue;
 249                         }
 250
 251                         /* Handle type specific I/O failures */
 252                         if (zio != NULL &&
 253                             handler->zi_record.zi_iotype != ZIO_TYPES &&
 254                             handler->zi_record.zi_iotype != zio->io_type)
 255                                 continue;
 256
 257                         if (handler->zi_record.zi_error == error) {
 258                                 /*
 259                                  * For a failed open, pretend like the device
 260                                  * has gone away.
 261                                  */
 262                                 if (error == ENXIO)
 263                                         vd->vdev_stat.vs_aux =
 264                                             VDEV_AUX_OPEN_FAILED;
 265
 266                                 /*
 267                                  * Treat these errors as if they had been
 268                                  * retried so that all the appropriate stats
 269                                  * and FMA events are generated.
 270                                  */
 271                                 if (!handler->zi_record.zi_failfast &&
 272                                     zio != NULL)
 273                                         zio->io_flags |= ZIO_FLAG_IO_RETRY;
 274
 275                                 ret = error;
 276                                 break;
 277                         }
 278                         if (handler->zi_record.zi_error == ENXIO) {
 279                                 ret = EIO;
 280                                 break;
 281                         }
 282                 }
 283         }
 284
 285         rw_exit(&inject_lock);
 286
 287         return (ret);
 288 }
 289
 290 /*
 291  * Simulate hardware that ignores cache flushes.  For requested number
 292  * of seconds nix the actual writing to disk.
 293  */
 294 void
 295 zio_handle_ignored_writes(zio_t *zio)
 296 {
 297         inject_handler_t *handler;
 298
 299         rw_enter(&inject_lock, RW_READER);
 300
 301         for (handler = list_head(&inject_handlers); handler != NULL;
 302             handler = list_next(&inject_handlers, handler)) {
 303
 304                 /* Ignore errors not destined for this pool */
 305                 if (zio->io_spa != handler->zi_spa ||
 306                     handler->zi_record.zi_cmd != ZINJECT_IGNORED_WRITES)
 307                         continue;
 308
 309                 /*
 310                  * Positive duration implies # of seconds, negative
 311                  * a number of txgs
 312                  */
 313                 if (handler->zi_record.zi_timer == 0) {
 314                         if (handler->zi_record.zi_duration > 0)
 315                                 handler->zi_record.zi_timer = ddi_get_lbolt64();
 316                         else
 317                                 handler->zi_record.zi_timer = zio->io_txg;
 318                 }
 319
 320                 /* Have a "problem" writing 60% of the time */
 321                 if (spa_get_random(100) < 60)
 322                         zio->io_pipeline &= ~ZIO_VDEV_IO_STAGES;
 323                 break;
 324         }
 325
 326         rw_exit(&inject_lock);
 327 }
 328
 329 void
 330 spa_handle_ignored_writes(spa_t *spa)
 331 {
 332         inject_handler_t *handler;
 333
 334         if (zio_injection_enabled == 0)
 335                 return;
 336
 337         rw_enter(&inject_lock, RW_READER);
 338
 339         for (handler = list_head(&inject_handlers); handler != NULL;
 340             handler = list_next(&inject_handlers, handler)) {
 341
 342                 if (spa != handler->zi_spa ||
 343                     handler->zi_record.zi_cmd != ZINJECT_IGNORED_WRITES)
 344                         continue;
 345
 346                 if (handler->zi_record.zi_duration > 0) {
 347                         VERIFY(handler->zi_record.zi_timer == 0 ||
 348                             handler->zi_record.zi_timer +
 349                             handler->zi_record.zi_duration * hz >
 350                             ddi_get_lbolt64());
 351                 } else {
 352                         /* duration is negative so the subtraction here adds */
 353                         VERIFY(handler->zi_record.zi_timer == 0 ||
 354                             handler->zi_record.zi_timer -
 355                             handler->zi_record.zi_duration >=
 356                             spa_syncing_txg(spa));
 357                 }
 358         }
 359
 360         rw_exit(&inject_lock);
 361 }
 362
 363 uint64_t
 364 zio_handle_io_delay(zio_t *zio)
 365 {
 366         vdev_t *vd = zio->io_vd;
 367         inject_handler_t *handler;
 368         uint64_t seconds = 0;
 369
 370         if (zio_injection_enabled == 0)
 371                 return (0);
 372
 373         rw_enter(&inject_lock, RW_READER);
 374
 375         for (handler = list_head(&inject_handlers); handler != NULL;
 376             handler = list_next(&inject_handlers, handler)) {
 377
 378                 if (handler->zi_record.zi_cmd != ZINJECT_DELAY_IO)
 379                         continue;
 380
 381                 if (vd->vdev_guid == handler->zi_record.zi_guid) {
 382                         seconds = handler->zi_record.zi_timer;
 383                         break;
 384                 }
 385
 386         }
 387         rw_exit(&inject_lock);
 388         return (seconds);
 389 }
 390
 391 /*
 392  * Create a new handler for the given record.  We add it to the list, adding
 393  * a reference to the spa_t in the process.  We increment zio_injection_enabled,
 394  * which is the switch to trigger all fault injection.
 395  */
 396 int
 397 zio_inject_fault(char *name, int flags, int *id, zinject_record_t *record)
 398 {
 399         inject_handler_t *handler;
 400         int error;
 401         spa_t *spa;
 402
 403         /*
 404          * If this is pool-wide metadata, make sure we unload the corresponding
 405          * spa_t, so that the next attempt to load it will trigger the fault.
 406          * We call spa_reset() to unload the pool appropriately.
 407          */
 408         if (flags & ZINJECT_UNLOAD_SPA)
 409                 if ((error = spa_reset(name)) != 0)
 410                         return (error);
 411
 412         if (!(flags & ZINJECT_NULL)) {
 413                 /*
 414                  * spa_inject_ref() will add an injection reference, which will
 415                  * prevent the pool from being removed from the namespace while
 416                  * still allowing it to be unloaded.
 417                  */
 418                 if ((spa = spa_inject_addref(name)) == NULL)
 419                         return (ENOENT);
 420
 421                 handler = kmem_alloc(sizeof (inject_handler_t), KM_SLEEP);
 422
 423                 rw_enter(&inject_lock, RW_WRITER);
 424
 425                 *id = handler->zi_id = inject_next_id++;
 426                 handler->zi_spa = spa;
 427                 handler->zi_record = *record;
 428                 list_insert_tail(&inject_handlers, handler);
 429                 atomic_add_32(&zio_injection_enabled, 1);
 430
 431                 rw_exit(&inject_lock);
 432         }
 433
 434         /*
 435          * Flush the ARC, so that any attempts to read this data will end up
 436          * going to the ZIO layer.  Note that this is a little overkill, but
 437          * we don't have the necessary ARC interfaces to do anything else, and
 438          * fault injection isn't a performance critical path.
 439          */
 440         if (flags & ZINJECT_FLUSH_ARC)
 441                 arc_flush(NULL);
 442
 443         return (0);
 444 }
 445
 446 /*
 447  * Returns the next record with an ID greater than that supplied to the
 448  * function.  Used to iterate over all handlers in the system.
 449  */
 450 int
 451 zio_inject_list_next(int *id, char *name, size_t buflen,
 452     zinject_record_t *record)
 453 {
 454         inject_handler_t *handler;
 455         int ret;
 456
 457         mutex_enter(&spa_namespace_lock);
 458         rw_enter(&inject_lock, RW_READER);
 459
 460         for (handler = list_head(&inject_handlers); handler != NULL;
 461             handler = list_next(&inject_handlers, handler))
 462                 if (handler->zi_id > *id)
 463                         break;
 464
 465         if (handler) {
 466                 *record = handler->zi_record;
 467                 *id = handler->zi_id;
 468                 (void) strncpy(name, spa_name(handler->zi_spa), buflen);
 469                 ret = 0;
 470         } else {
 471                 ret = ENOENT;
 472         }
 473
 474         rw_exit(&inject_lock);
 475         mutex_exit(&spa_namespace_lock);
 476
 477         return (ret);
 478 }
 479
 480 /*
 481  * Clear the fault handler with the given identifier, or return ENOENT if none
 482  * exists.
 483  */
 484 int
 485 zio_clear_fault(int id)
 486 {
 487         inject_handler_t *handler;
 488
 489         rw_enter(&inject_lock, RW_WRITER);
 490
 491         for (handler = list_head(&inject_handlers); handler != NULL;
 492             handler = list_next(&inject_handlers, handler))
 493                 if (handler->zi_id == id)
 494                         break;
 495
 496         if (handler == NULL) {
 497                 rw_exit(&inject_lock);
 498                 return (ENOENT);
 499         }
 500
 501         list_remove(&inject_handlers, handler);
 502         rw_exit(&inject_lock);
 503
 504         spa_inject_delref(handler->zi_spa);
 505         kmem_free(handler, sizeof (inject_handler_t));
 506         atomic_add_32(&zio_injection_enabled, -1);
 507
 508         return (0);
 509 }
 510
 511 void
 512 zio_inject_init(void)
 513 {
 514         rw_init(&inject_lock, NULL, RW_DEFAULT, NULL);
 515         list_create(&inject_handlers, sizeof (inject_handler_t),
 516             offsetof(inject_handler_t, zi_link));
 517 }
 518
 519 void
 520 zio_inject_fini(void)
 521 {
 522         list_destroy(&inject_handlers);
 523         rw_destroy(&inject_lock);
 524 }