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 /*
  23  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  25  * Copyright (c) 2012 by Delphix. All rights reserved.
  26  */
  27 
  28 #include <sys/zfs_context.h>
  29 #include <sys/fm/fs/zfs.h>
  30 #include <sys/spa.h>
  31 #include <sys/spa_impl.h>
  32 #include <sys/dmu.h>
  33 #include <sys/dmu_tx.h>
  34 #include <sys/vdev_impl.h>
  35 #include <sys/uberblock_impl.h>
  36 #include <sys/metaslab.h>
  37 #include <sys/metaslab_impl.h>
  38 #include <sys/space_map.h>
  39 #include <sys/zio.h>
  40 #include <sys/zap.h>
  41 #include <sys/fs/zfs.h>
  42 #include <sys/arc.h>
  43 #include <sys/zil.h>
  44 #include <sys/dsl_scan.h>
  45 
  46 /*
  47  * Virtual device management.
  48  */
  49 
  50 static vdev_ops_t *vdev_ops_table[] = {
  51         &vdev_root_ops,
  52         &vdev_raidz_ops,
  53         &vdev_mirror_ops,
  54         &vdev_replacing_ops,
  55         &vdev_spare_ops,
  56         &vdev_disk_ops,
  57         &vdev_file_ops,
  58         &vdev_missing_ops,
  59         &vdev_hole_ops,
  60         NULL
  61 };
  62 
  63 /* maximum scrub/resilver I/O queue per leaf vdev */
  64 int zfs_scrub_limit = 10;
  65 
  66 /*
  67  * Given a vdev type, return the appropriate ops vector.
  68  */
  69 static vdev_ops_t *
  70 vdev_getops(const char *type)
  71 {
  72         vdev_ops_t *ops, **opspp;
  73 
  74         for (opspp = vdev_ops_table; (ops = *opspp) != NULL; opspp++)
  75                 if (strcmp(ops->vdev_op_type, type) == 0)
  76                         break;
  77 
  78         return (ops);
  79 }
  80 
  81 /*
  82  * Default asize function: return the MAX of psize with the asize of
  83  * all children.  This is what's used by anything other than RAID-Z.
  84  */
  85 uint64_t
  86 vdev_default_asize(vdev_t *vd, uint64_t psize)
  87 {
  88         uint64_t asize = P2ROUNDUP(psize, 1ULL << vd->vdev_top->vdev_ashift);
  89         uint64_t csize;
  90 
  91         for (int c = 0; c < vd->vdev_children; c++) {
  92                 csize = vdev_psize_to_asize(vd->vdev_child[c], psize);
  93                 asize = MAX(asize, csize);
  94         }
  95 
  96         return (asize);
  97 }
  98 
  99 /*
 100  * Get the minimum allocatable size. We define the allocatable size as
 101  * the vdev's asize rounded to the nearest metaslab. This allows us to
 102  * replace or attach devices which don't have the same physical size but
 103  * can still satisfy the same number of allocations.
 104  */
 105 uint64_t
 106 vdev_get_min_asize(vdev_t *vd)
 107 {
 108         vdev_t *pvd = vd->vdev_parent;
 109 
 110         /*
 111          * If our parent is NULL (inactive spare or cache) or is the root,
 112          * just return our own asize.
 113          */
 114         if (pvd == NULL)
 115                 return (vd->vdev_asize);
 116 
 117         /*
 118          * The top-level vdev just returns the allocatable size rounded
 119          * to the nearest metaslab.
 120          */
 121         if (vd == vd->vdev_top)
 122                 return (P2ALIGN(vd->vdev_asize, 1ULL << vd->vdev_ms_shift));
 123 
 124         /*
 125          * The allocatable space for a raidz vdev is N * sizeof(smallest child),
 126          * so each child must provide at least 1/Nth of its asize.
 127          */
 128         if (pvd->vdev_ops == &vdev_raidz_ops)
 129                 return (pvd->vdev_min_asize / pvd->vdev_children);
 130 
 131         return (pvd->vdev_min_asize);
 132 }
 133 
 134 void
 135 vdev_set_min_asize(vdev_t *vd)
 136 {
 137         vd->vdev_min_asize = vdev_get_min_asize(vd);
 138 
 139         for (int c = 0; c < vd->vdev_children; c++)
 140                 vdev_set_min_asize(vd->vdev_child[c]);
 141 }
 142 
 143 vdev_t *
 144 vdev_lookup_top(spa_t *spa, uint64_t vdev)
 145 {
 146         vdev_t *rvd = spa->spa_root_vdev;
 147 
 148         ASSERT(spa_config_held(spa, SCL_ALL, RW_READER) != 0);
 149 
 150         if (vdev < rvd->vdev_children) {
 151                 ASSERT(rvd->vdev_child[vdev] != NULL);
 152                 return (rvd->vdev_child[vdev]);
 153         }
 154 
 155         return (NULL);
 156 }
 157 
 158 vdev_t *
 159 vdev_lookup_by_guid(vdev_t *vd, uint64_t guid)
 160 {
 161         vdev_t *mvd;
 162 
 163         if (vd->vdev_guid == guid)
 164                 return (vd);
 165 
 166         for (int c = 0; c < vd->vdev_children; c++)
 167                 if ((mvd = vdev_lookup_by_guid(vd->vdev_child[c], guid)) !=
 168                     NULL)
 169                         return (mvd);
 170 
 171         return (NULL);
 172 }
 173 
 174 void
 175 vdev_add_child(vdev_t *pvd, vdev_t *cvd)
 176 {
 177         size_t oldsize, newsize;
 178         uint64_t id = cvd->vdev_id;
 179         vdev_t **newchild;
 180 
 181         ASSERT(spa_config_held(cvd->vdev_spa, SCL_ALL, RW_WRITER) == SCL_ALL);
 182         ASSERT(cvd->vdev_parent == NULL);
 183 
 184         cvd->vdev_parent = pvd;
 185 
 186         if (pvd == NULL)
 187                 return;
 188 
 189         ASSERT(id >= pvd->vdev_children || pvd->vdev_child[id] == NULL);
 190 
 191         oldsize = pvd->vdev_children * sizeof (vdev_t *);
 192         pvd->vdev_children = MAX(pvd->vdev_children, id + 1);
 193         newsize = pvd->vdev_children * sizeof (vdev_t *);
 194 
 195         newchild = kmem_zalloc(newsize, KM_SLEEP);
 196         if (pvd->vdev_child != NULL) {
 197                 bcopy(pvd->vdev_child, newchild, oldsize);
 198                 kmem_free(pvd->vdev_child, oldsize);
 199         }
 200 
 201         pvd->vdev_child = newchild;
 202         pvd->vdev_child[id] = cvd;
 203 
 204         cvd->vdev_top = (pvd->vdev_top ? pvd->vdev_top: cvd);
 205         ASSERT(cvd->vdev_top->vdev_parent->vdev_parent == NULL);
 206 
 207         /*
 208          * Walk up all ancestors to update guid sum.
 209          */
 210         for (; pvd != NULL; pvd = pvd->vdev_parent)
 211                 pvd->vdev_guid_sum += cvd->vdev_guid_sum;
 212 }
 213 
 214 void
 215 vdev_remove_child(vdev_t *pvd, vdev_t *cvd)
 216 {
 217         int c;
 218         uint_t id = cvd->vdev_id;
 219 
 220         ASSERT(cvd->vdev_parent == pvd);
 221 
 222         if (pvd == NULL)
 223                 return;
 224 
 225         ASSERT(id < pvd->vdev_children);
 226         ASSERT(pvd->vdev_child[id] == cvd);
 227 
 228         pvd->vdev_child[id] = NULL;
 229         cvd->vdev_parent = NULL;
 230 
 231         for (c = 0; c < pvd->vdev_children; c++)
 232                 if (pvd->vdev_child[c])
 233                         break;
 234 
 235         if (c == pvd->vdev_children) {
 236                 kmem_free(pvd->vdev_child, c * sizeof (vdev_t *));
 237                 pvd->vdev_child = NULL;
 238                 pvd->vdev_children = 0;
 239         }
 240 
 241         /*
 242          * Walk up all ancestors to update guid sum.
 243          */
 244         for (; pvd != NULL; pvd = pvd->vdev_parent)
 245                 pvd->vdev_guid_sum -= cvd->vdev_guid_sum;
 246 }
 247 
 248 /*
 249  * Remove any holes in the child array.
 250  */
 251 void
 252 vdev_compact_children(vdev_t *pvd)
 253 {
 254         vdev_t **newchild, *cvd;
 255         int oldc = pvd->vdev_children;
 256         int newc;
 257 
 258         ASSERT(spa_config_held(pvd->vdev_spa, SCL_ALL, RW_WRITER) == SCL_ALL);
 259 
 260         for (int c = newc = 0; c < oldc; c++)
 261                 if (pvd->vdev_child[c])
 262                         newc++;
 263 
 264         newchild = kmem_alloc(newc * sizeof (vdev_t *), KM_SLEEP);
 265 
 266         for (int c = newc = 0; c < oldc; c++) {
 267                 if ((cvd = pvd->vdev_child[c]) != NULL) {
 268                         newchild[newc] = cvd;
 269                         cvd->vdev_id = newc++;
 270                 }
 271         }
 272 
 273         kmem_free(pvd->vdev_child, oldc * sizeof (vdev_t *));
 274         pvd->vdev_child = newchild;
 275         pvd->vdev_children = newc;
 276 }
 277 
 278 /*
 279  * Allocate and minimally initialize a vdev_t.
 280  */
 281 vdev_t *
 282 vdev_alloc_common(spa_t *spa, uint_t id, uint64_t guid, vdev_ops_t *ops)
 283 {
 284         vdev_t *vd;
 285 
 286         vd = kmem_zalloc(sizeof (vdev_t), KM_SLEEP);
 287 
 288         if (spa->spa_root_vdev == NULL) {
 289                 ASSERT(ops == &vdev_root_ops);
 290                 spa->spa_root_vdev = vd;
 291                 spa->spa_load_guid = spa_generate_guid(NULL);
 292         }
 293 
 294         if (guid == 0 && ops != &vdev_hole_ops) {
 295                 if (spa->spa_root_vdev == vd) {
 296                         /*
 297                          * The root vdev's guid will also be the pool guid,
 298                          * which must be unique among all pools.
 299                          */
 300                         guid = spa_generate_guid(NULL);
 301                 } else {
 302                         /*
 303                          * Any other vdev's guid must be unique within the pool.
 304                          */
 305                         guid = spa_generate_guid(spa);
 306                 }
 307                 ASSERT(!spa_guid_exists(spa_guid(spa), guid));
 308         }
 309 
 310         vd->vdev_spa = spa;
 311         vd->vdev_id = id;
 312         vd->vdev_guid = guid;
 313         vd->vdev_guid_sum = guid;
 314         vd->vdev_ops = ops;
 315         vd->vdev_state = VDEV_STATE_CLOSED;
 316         vd->vdev_ishole = (ops == &vdev_hole_ops);
 317 
 318         mutex_init(&vd->vdev_dtl_lock, NULL, MUTEX_DEFAULT, NULL);
 319         mutex_init(&vd->vdev_stat_lock, NULL, MUTEX_DEFAULT, NULL);
 320         mutex_init(&vd->vdev_probe_lock, NULL, MUTEX_DEFAULT, NULL);
 321         for (int t = 0; t < DTL_TYPES; t++) {
 322                 space_map_create(&vd->vdev_dtl[t], 0, -1ULL, 0,
 323                     &vd->vdev_dtl_lock);
 324         }
 325         txg_list_create(&vd->vdev_ms_list,
 326             offsetof(struct metaslab, ms_txg_node));
 327         txg_list_create(&vd->vdev_dtl_list,
 328             offsetof(struct vdev, vdev_dtl_node));
 329         vd->vdev_stat.vs_timestamp = gethrtime();
 330         vdev_queue_init(vd);
 331         vdev_cache_init(vd);
 332 
 333         return (vd);
 334 }
 335 
 336 /*
 337  * Allocate a new vdev.  The 'alloctype' is used to control whether we are
 338  * creating a new vdev or loading an existing one - the behavior is slightly
 339  * different for each case.
 340  */
 341 int
 342 vdev_alloc(spa_t *spa, vdev_t **vdp, nvlist_t *nv, vdev_t *parent, uint_t id,
 343     int alloctype)
 344 {
 345         vdev_ops_t *ops;
 346         char *type;
 347         uint64_t guid = 0, islog, nparity;
 348         vdev_t *vd;
 349 
 350         ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL);
 351 
 352         if (nvlist_lookup_string(nv, ZPOOL_CONFIG_TYPE, &type) != 0)
 353                 return (EINVAL);
 354 
 355         if ((ops = vdev_getops(type)) == NULL)
 356                 return (EINVAL);
 357 
 358         /*
 359          * If this is a load, get the vdev guid from the nvlist.
 360          * Otherwise, vdev_alloc_common() will generate one for us.
 361          */
 362         if (alloctype == VDEV_ALLOC_LOAD) {
 363                 uint64_t label_id;
 364 
 365                 if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_ID, &label_id) ||
 366                     label_id != id)
 367                         return (EINVAL);
 368 
 369                 if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_GUID, &guid) != 0)
 370                         return (EINVAL);
 371         } else if (alloctype == VDEV_ALLOC_SPARE) {
 372                 if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_GUID, &guid) != 0)
 373                         return (EINVAL);
 374         } else if (alloctype == VDEV_ALLOC_L2CACHE) {
 375                 if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_GUID, &guid) != 0)
 376                         return (EINVAL);
 377         } else if (alloctype == VDEV_ALLOC_ROOTPOOL) {
 378                 if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_GUID, &guid) != 0)
 379                         return (EINVAL);
 380         }
 381 
 382         /*
 383          * The first allocated vdev must be of type 'root'.
 384          */
 385         if (ops != &vdev_root_ops && spa->spa_root_vdev == NULL)
 386                 return (EINVAL);
 387 
 388         /*
 389          * Determine whether we're a log vdev.
 390          */
 391         islog = 0;
 392         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_IS_LOG, &islog);
 393         if (islog && spa_version(spa) < SPA_VERSION_SLOGS)
 394                 return (ENOTSUP);
 395 
 396         if (ops == &vdev_hole_ops && spa_version(spa) < SPA_VERSION_HOLES)
 397                 return (ENOTSUP);
 398 
 399         /*
 400          * Set the nparity property for RAID-Z vdevs.
 401          */
 402         nparity = -1ULL;
 403         if (ops == &vdev_raidz_ops) {
 404                 if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_NPARITY,
 405                     &nparity) == 0) {
 406                         if (nparity == 0 || nparity > VDEV_RAIDZ_MAXPARITY)
 407                                 return (EINVAL);
 408                         /*
 409                          * Previous versions could only support 1 or 2 parity
 410                          * device.
 411                          */
 412                         if (nparity > 1 &&
 413                             spa_version(spa) < SPA_VERSION_RAIDZ2)
 414                                 return (ENOTSUP);
 415                         if (nparity > 2 &&
 416                             spa_version(spa) < SPA_VERSION_RAIDZ3)
 417                                 return (ENOTSUP);
 418                 } else {
 419                         /*
 420                          * We require the parity to be specified for SPAs that
 421                          * support multiple parity levels.
 422                          */
 423                         if (spa_version(spa) >= SPA_VERSION_RAIDZ2)
 424                                 return (EINVAL);
 425                         /*
 426                          * Otherwise, we default to 1 parity device for RAID-Z.
 427                          */
 428                         nparity = 1;
 429                 }
 430         } else {
 431                 nparity = 0;
 432         }
 433         ASSERT(nparity != -1ULL);
 434 
 435         vd = vdev_alloc_common(spa, id, guid, ops);
 436 
 437         vd->vdev_islog = islog;
 438         vd->vdev_nparity = nparity;
 439 
 440         if (nvlist_lookup_string(nv, ZPOOL_CONFIG_PATH, &vd->vdev_path) == 0)
 441                 vd->vdev_path = spa_strdup(vd->vdev_path);
 442         if (nvlist_lookup_string(nv, ZPOOL_CONFIG_DEVID, &vd->vdev_devid) == 0)
 443                 vd->vdev_devid = spa_strdup(vd->vdev_devid);
 444         if (nvlist_lookup_string(nv, ZPOOL_CONFIG_PHYS_PATH,
 445             &vd->vdev_physpath) == 0)
 446                 vd->vdev_physpath = spa_strdup(vd->vdev_physpath);
 447         if (nvlist_lookup_string(nv, ZPOOL_CONFIG_FRU, &vd->vdev_fru) == 0)
 448                 vd->vdev_fru = spa_strdup(vd->vdev_fru);
 449 
 450         /*
 451          * Set the whole_disk property.  If it's not specified, leave the value
 452          * as -1.
 453          */
 454         if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_WHOLE_DISK,
 455             &vd->vdev_wholedisk) != 0)
 456                 vd->vdev_wholedisk = -1ULL;
 457 
 458         /*
 459          * Look for the 'not present' flag.  This will only be set if the device
 460          * was not present at the time of import.
 461          */
 462         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_NOT_PRESENT,
 463             &vd->vdev_not_present);
 464 
 465         /*
 466          * Get the alignment requirement.
 467          */
 468         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_ASHIFT, &vd->vdev_ashift);
 469 
 470         /*
 471          * Retrieve the vdev creation time.
 472          */
 473         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_CREATE_TXG,
 474             &vd->vdev_crtxg);
 475 
 476         /*
 477          * If we're a top-level vdev, try to load the allocation parameters.
 478          */
 479         if (parent && !parent->vdev_parent &&
 480             (alloctype == VDEV_ALLOC_LOAD || alloctype == VDEV_ALLOC_SPLIT)) {
 481                 (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_METASLAB_ARRAY,
 482                     &vd->vdev_ms_array);
 483                 (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_METASLAB_SHIFT,
 484                     &vd->vdev_ms_shift);
 485                 (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_ASIZE,
 486                     &vd->vdev_asize);
 487                 (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_REMOVING,
 488                     &vd->vdev_removing);
 489         }
 490 
 491         if (parent && !parent->vdev_parent && alloctype != VDEV_ALLOC_ATTACH) {
 492                 ASSERT(alloctype == VDEV_ALLOC_LOAD ||
 493                     alloctype == VDEV_ALLOC_ADD ||
 494                     alloctype == VDEV_ALLOC_SPLIT ||
 495                     alloctype == VDEV_ALLOC_ROOTPOOL);
 496                 vd->vdev_mg = metaslab_group_create(islog ?
 497                     spa_log_class(spa) : spa_normal_class(spa), vd);
 498         }
 499 
 500         /*
 501          * If we're a leaf vdev, try to load the DTL object and other state.
 502          */
 503         if (vd->vdev_ops->vdev_op_leaf &&
 504             (alloctype == VDEV_ALLOC_LOAD || alloctype == VDEV_ALLOC_L2CACHE ||
 505             alloctype == VDEV_ALLOC_ROOTPOOL)) {
 506                 if (alloctype == VDEV_ALLOC_LOAD) {
 507                         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_DTL,
 508                             &vd->vdev_dtl_smo.smo_object);
 509                         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_UNSPARE,
 510                             &vd->vdev_unspare);
 511                 }
 512 
 513                 if (alloctype == VDEV_ALLOC_ROOTPOOL) {
 514                         uint64_t spare = 0;
 515 
 516                         if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_IS_SPARE,
 517                             &spare) == 0 && spare)
 518                                 spa_spare_add(vd);
 519                 }
 520 
 521                 (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_OFFLINE,
 522                     &vd->vdev_offline);
 523 
 524                 (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_RESILVERING,
 525                     &vd->vdev_resilvering);
 526 
 527                 /*
 528                  * When importing a pool, we want to ignore the persistent fault
 529                  * state, as the diagnosis made on another system may not be
 530                  * valid in the current context.  Local vdevs will
 531                  * remain in the faulted state.
 532                  */
 533                 if (spa_load_state(spa) == SPA_LOAD_OPEN) {
 534                         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_FAULTED,
 535                             &vd->vdev_faulted);
 536                         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_DEGRADED,
 537                             &vd->vdev_degraded);
 538                         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_REMOVED,
 539                             &vd->vdev_removed);
 540 
 541                         if (vd->vdev_faulted || vd->vdev_degraded) {
 542                                 char *aux;
 543 
 544                                 vd->vdev_label_aux =
 545                                     VDEV_AUX_ERR_EXCEEDED;
 546                                 if (nvlist_lookup_string(nv,
 547                                     ZPOOL_CONFIG_AUX_STATE, &aux) == 0 &&
 548                                     strcmp(aux, "external") == 0)
 549                                         vd->vdev_label_aux = VDEV_AUX_EXTERNAL;
 550                         }
 551                 }
 552         }
 553 
 554         /*
 555          * Add ourselves to the parent's list of children.
 556          */
 557         vdev_add_child(parent, vd);
 558 
 559         *vdp = vd;
 560 
 561         return (0);
 562 }
 563 
 564 void
 565 vdev_free(vdev_t *vd)
 566 {
 567         spa_t *spa = vd->vdev_spa;
 568 
 569         /*
 570          * vdev_free() implies closing the vdev first.  This is simpler than
 571          * trying to ensure complicated semantics for all callers.
 572          */
 573         vdev_close(vd);
 574 
 575         ASSERT(!list_link_active(&vd->vdev_config_dirty_node));
 576         ASSERT(!list_link_active(&vd->vdev_state_dirty_node));
 577 
 578         /*
 579          * Free all children.
 580          */
 581         for (int c = 0; c < vd->vdev_children; c++)
 582                 vdev_free(vd->vdev_child[c]);
 583 
 584         ASSERT(vd->vdev_child == NULL);
 585         ASSERT(vd->vdev_guid_sum == vd->vdev_guid);
 586 
 587         /*
 588          * Discard allocation state.
 589          */
 590         if (vd->vdev_mg != NULL) {
 591                 vdev_metaslab_fini(vd);
 592                 metaslab_group_destroy(vd->vdev_mg);
 593         }
 594 
 595         ASSERT3U(vd->vdev_stat.vs_space, ==, 0);
 596         ASSERT3U(vd->vdev_stat.vs_dspace, ==, 0);
 597         ASSERT3U(vd->vdev_stat.vs_alloc, ==, 0);
 598 
 599         /*
 600          * Remove this vdev from its parent's child list.
 601          */
 602         vdev_remove_child(vd->vdev_parent, vd);
 603 
 604         ASSERT(vd->vdev_parent == NULL);
 605 
 606         /*
 607          * Clean up vdev structure.
 608          */
 609         vdev_queue_fini(vd);
 610         vdev_cache_fini(vd);
 611 
 612         if (vd->vdev_path)
 613                 spa_strfree(vd->vdev_path);
 614         if (vd->vdev_devid)
 615                 spa_strfree(vd->vdev_devid);
 616         if (vd->vdev_physpath)
 617                 spa_strfree(vd->vdev_physpath);
 618         if (vd->vdev_fru)
 619                 spa_strfree(vd->vdev_fru);
 620 
 621         if (vd->vdev_isspare)
 622                 spa_spare_remove(vd);
 623         if (vd->vdev_isl2cache)
 624                 spa_l2cache_remove(vd);
 625 
 626         txg_list_destroy(&vd->vdev_ms_list);
 627         txg_list_destroy(&vd->vdev_dtl_list);
 628 
 629         mutex_enter(&vd->vdev_dtl_lock);
 630         for (int t = 0; t < DTL_TYPES; t++) {
 631                 space_map_unload(&vd->vdev_dtl[t]);
 632                 space_map_destroy(&vd->vdev_dtl[t]);
 633         }
 634         mutex_exit(&vd->vdev_dtl_lock);
 635 
 636         mutex_destroy(&vd->vdev_dtl_lock);
 637         mutex_destroy(&vd->vdev_stat_lock);
 638         mutex_destroy(&vd->vdev_probe_lock);
 639 
 640         if (vd == spa->spa_root_vdev)
 641                 spa->spa_root_vdev = NULL;
 642 
 643         kmem_free(vd, sizeof (vdev_t));
 644 }
 645 
 646 /*
 647  * Transfer top-level vdev state from svd to tvd.
 648  */
 649 static void
 650 vdev_top_transfer(vdev_t *svd, vdev_t *tvd)
 651 {
 652         spa_t *spa = svd->vdev_spa;
 653         metaslab_t *msp;
 654         vdev_t *vd;
 655         int t;
 656 
 657         ASSERT(tvd == tvd->vdev_top);
 658 
 659         tvd->vdev_ms_array = svd->vdev_ms_array;
 660         tvd->vdev_ms_shift = svd->vdev_ms_shift;
 661         tvd->vdev_ms_count = svd->vdev_ms_count;
 662 
 663         svd->vdev_ms_array = 0;
 664         svd->vdev_ms_shift = 0;
 665         svd->vdev_ms_count = 0;
 666 
 667         if (tvd->vdev_mg)
 668                 ASSERT3P(tvd->vdev_mg, ==, svd->vdev_mg);
 669         tvd->vdev_mg = svd->vdev_mg;
 670         tvd->vdev_ms = svd->vdev_ms;
 671 
 672         svd->vdev_mg = NULL;
 673         svd->vdev_ms = NULL;
 674 
 675         if (tvd->vdev_mg != NULL)
 676                 tvd->vdev_mg->mg_vd = tvd;
 677 
 678         tvd->vdev_stat.vs_alloc = svd->vdev_stat.vs_alloc;
 679         tvd->vdev_stat.vs_space = svd->vdev_stat.vs_space;
 680         tvd->vdev_stat.vs_dspace = svd->vdev_stat.vs_dspace;
 681 
 682         svd->vdev_stat.vs_alloc = 0;
 683         svd->vdev_stat.vs_space = 0;
 684         svd->vdev_stat.vs_dspace = 0;
 685 
 686         for (t = 0; t < TXG_SIZE; t++) {
 687                 while ((msp = txg_list_remove(&svd->vdev_ms_list, t)) != NULL)
 688                         (void) txg_list_add(&tvd->vdev_ms_list, msp, t);
 689                 while ((vd = txg_list_remove(&svd->vdev_dtl_list, t)) != NULL)
 690                         (void) txg_list_add(&tvd->vdev_dtl_list, vd, t);
 691                 if (txg_list_remove_this(&spa->spa_vdev_txg_list, svd, t))
 692                         (void) txg_list_add(&spa->spa_vdev_txg_list, tvd, t);
 693         }
 694 
 695         if (list_link_active(&svd->vdev_config_dirty_node)) {
 696                 vdev_config_clean(svd);
 697                 vdev_config_dirty(tvd);
 698         }
 699 
 700         if (list_link_active(&svd->vdev_state_dirty_node)) {
 701                 vdev_state_clean(svd);
 702                 vdev_state_dirty(tvd);
 703         }
 704 
 705         tvd->vdev_deflate_ratio = svd->vdev_deflate_ratio;
 706         svd->vdev_deflate_ratio = 0;
 707 
 708         tvd->vdev_islog = svd->vdev_islog;
 709         svd->vdev_islog = 0;
 710 }
 711 
 712 static void
 713 vdev_top_update(vdev_t *tvd, vdev_t *vd)
 714 {
 715         if (vd == NULL)
 716                 return;
 717 
 718         vd->vdev_top = tvd;
 719 
 720         for (int c = 0; c < vd->vdev_children; c++)
 721                 vdev_top_update(tvd, vd->vdev_child[c]);
 722 }
 723 
 724 /*
 725  * Add a mirror/replacing vdev above an existing vdev.
 726  */
 727 vdev_t *
 728 vdev_add_parent(vdev_t *cvd, vdev_ops_t *ops)
 729 {
 730         spa_t *spa = cvd->vdev_spa;
 731         vdev_t *pvd = cvd->vdev_parent;
 732         vdev_t *mvd;
 733 
 734         ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL);
 735 
 736         mvd = vdev_alloc_common(spa, cvd->vdev_id, 0, ops);
 737 
 738         mvd->vdev_asize = cvd->vdev_asize;
 739         mvd->vdev_min_asize = cvd->vdev_min_asize;
 740         mvd->vdev_max_asize = cvd->vdev_max_asize;
 741         mvd->vdev_ashift = cvd->vdev_ashift;
 742         mvd->vdev_state = cvd->vdev_state;
 743         mvd->vdev_crtxg = cvd->vdev_crtxg;
 744 
 745         vdev_remove_child(pvd, cvd);
 746         vdev_add_child(pvd, mvd);
 747         cvd->vdev_id = mvd->vdev_children;
 748         vdev_add_child(mvd, cvd);
 749         vdev_top_update(cvd->vdev_top, cvd->vdev_top);
 750 
 751         if (mvd == mvd->vdev_top)
 752                 vdev_top_transfer(cvd, mvd);
 753 
 754         return (mvd);
 755 }
 756 
 757 /*
 758  * Remove a 1-way mirror/replacing vdev from the tree.
 759  */
 760 void
 761 vdev_remove_parent(vdev_t *cvd)
 762 {
 763         vdev_t *mvd = cvd->vdev_parent;
 764         vdev_t *pvd = mvd->vdev_parent;
 765 
 766         ASSERT(spa_config_held(cvd->vdev_spa, SCL_ALL, RW_WRITER) == SCL_ALL);
 767 
 768         ASSERT(mvd->vdev_children == 1);
 769         ASSERT(mvd->vdev_ops == &vdev_mirror_ops ||
 770             mvd->vdev_ops == &vdev_replacing_ops ||
 771             mvd->vdev_ops == &vdev_spare_ops);
 772         cvd->vdev_ashift = mvd->vdev_ashift;
 773 
 774         vdev_remove_child(mvd, cvd);
 775         vdev_remove_child(pvd, mvd);
 776 
 777         /*
 778          * If cvd will replace mvd as a top-level vdev, preserve mvd's guid.
 779          * Otherwise, we could have detached an offline device, and when we
 780          * go to import the pool we'll think we have two top-level vdevs,
 781          * instead of a different version of the same top-level vdev.
 782          */
 783         if (mvd->vdev_top == mvd) {
 784                 uint64_t guid_delta = mvd->vdev_guid - cvd->vdev_guid;
 785                 cvd->vdev_orig_guid = cvd->vdev_guid;
 786                 cvd->vdev_guid += guid_delta;
 787                 cvd->vdev_guid_sum += guid_delta;
 788         }
 789         cvd->vdev_id = mvd->vdev_id;
 790         vdev_add_child(pvd, cvd);
 791         vdev_top_update(cvd->vdev_top, cvd->vdev_top);
 792 
 793         if (cvd == cvd->vdev_top)
 794                 vdev_top_transfer(mvd, cvd);
 795 
 796         ASSERT(mvd->vdev_children == 0);
 797         vdev_free(mvd);
 798 }
 799 
 800 int
 801 vdev_metaslab_init(vdev_t *vd, uint64_t txg)
 802 {
 803         spa_t *spa = vd->vdev_spa;
 804         objset_t *mos = spa->spa_meta_objset;
 805         uint64_t m;
 806         uint64_t oldc = vd->vdev_ms_count;
 807         uint64_t newc = vd->vdev_asize >> vd->vdev_ms_shift;
 808         metaslab_t **mspp;
 809         int error;
 810 
 811         ASSERT(txg == 0 || spa_config_held(spa, SCL_ALLOC, RW_WRITER));
 812 
 813         /*
 814          * This vdev is not being allocated from yet or is a hole.
 815          */
 816         if (vd->vdev_ms_shift == 0)
 817                 return (0);
 818 
 819         ASSERT(!vd->vdev_ishole);
 820 
 821         /*
 822          * Compute the raidz-deflation ratio.  Note, we hard-code
 823          * in 128k (1 << 17) because it is the current "typical" blocksize.
 824          * Even if SPA_MAXBLOCKSIZE changes, this algorithm must never change,
 825          * or we will inconsistently account for existing bp's.
 826          */
 827         vd->vdev_deflate_ratio = (1 << 17) /
 828             (vdev_psize_to_asize(vd, 1 << 17) >> SPA_MINBLOCKSHIFT);
 829 
 830         ASSERT(oldc <= newc);
 831 
 832         mspp = kmem_zalloc(newc * sizeof (*mspp), KM_SLEEP);
 833 
 834         if (oldc != 0) {
 835                 bcopy(vd->vdev_ms, mspp, oldc * sizeof (*mspp));
 836                 kmem_free(vd->vdev_ms, oldc * sizeof (*mspp));
 837         }
 838 
 839         vd->vdev_ms = mspp;
 840         vd->vdev_ms_count = newc;
 841 
 842         for (m = oldc; m < newc; m++) {
 843                 space_map_obj_t smo = { 0, 0, 0 };
 844                 if (txg == 0) {
 845                         uint64_t object = 0;
 846                         error = dmu_read(mos, vd->vdev_ms_array,
 847                             m * sizeof (uint64_t), sizeof (uint64_t), &object,
 848                             DMU_READ_PREFETCH);
 849                         if (error)
 850                                 return (error);
 851                         if (object != 0) {
 852                                 dmu_buf_t *db;
 853                                 error = dmu_bonus_hold(mos, object, FTAG, &db);
 854                                 if (error)
 855                                         return (error);
 856                                 ASSERT3U(db->db_size, >=, sizeof (smo));
 857                                 bcopy(db->db_data, &smo, sizeof (smo));
 858                                 ASSERT3U(smo.smo_object, ==, object);
 859                                 dmu_buf_rele(db, FTAG);
 860                         }
 861                 }
 862                 vd->vdev_ms[m] = metaslab_init(vd->vdev_mg, &smo,
 863                     m << vd->vdev_ms_shift, 1ULL << vd->vdev_ms_shift, txg);
 864         }
 865 
 866         if (txg == 0)
 867                 spa_config_enter(spa, SCL_ALLOC, FTAG, RW_WRITER);
 868 
 869         /*
 870          * If the vdev is being removed we don't activate
 871          * the metaslabs since we want to ensure that no new
 872          * allocations are performed on this device.
 873          */
 874         if (oldc == 0 && !vd->vdev_removing)
 875                 metaslab_group_activate(vd->vdev_mg);
 876 
 877         if (txg == 0)
 878                 spa_config_exit(spa, SCL_ALLOC, FTAG);
 879 
 880         return (0);
 881 }
 882 
 883 void
 884 vdev_metaslab_fini(vdev_t *vd)
 885 {
 886         uint64_t m;
 887         uint64_t count = vd->vdev_ms_count;
 888 
 889         if (vd->vdev_ms != NULL) {
 890                 metaslab_group_passivate(vd->vdev_mg);
 891                 for (m = 0; m < count; m++)
 892                         if (vd->vdev_ms[m] != NULL)
 893                                 metaslab_fini(vd->vdev_ms[m]);
 894                 kmem_free(vd->vdev_ms, count * sizeof (metaslab_t *));
 895                 vd->vdev_ms = NULL;
 896         }
 897 }
 898 
 899 typedef struct vdev_probe_stats {
 900         boolean_t       vps_readable;
 901         boolean_t       vps_writeable;
 902         int             vps_flags;
 903 } vdev_probe_stats_t;
 904 
 905 static void
 906 vdev_probe_done(zio_t *zio)
 907 {
 908         spa_t *spa = zio->io_spa;
 909         vdev_t *vd = zio->io_vd;
 910         vdev_probe_stats_t *vps = zio->io_private;
 911 
 912         ASSERT(vd->vdev_probe_zio != NULL);
 913 
 914         if (zio->io_type == ZIO_TYPE_READ) {
 915                 if (zio->io_error == 0)
 916                         vps->vps_readable = 1;
 917                 if (zio->io_error == 0 && spa_writeable(spa)) {
 918                         zio_nowait(zio_write_phys(vd->vdev_probe_zio, vd,
 919                             zio->io_offset, zio->io_size, zio->io_data,
 920                             ZIO_CHECKSUM_OFF, vdev_probe_done, vps,
 921                             ZIO_PRIORITY_SYNC_WRITE, vps->vps_flags, B_TRUE));
 922                 } else {
 923                         zio_buf_free(zio->io_data, zio->io_size);
 924                 }
 925         } else if (zio->io_type == ZIO_TYPE_WRITE) {
 926                 if (zio->io_error == 0)
 927                         vps->vps_writeable = 1;
 928                 zio_buf_free(zio->io_data, zio->io_size);
 929         } else if (zio->io_type == ZIO_TYPE_NULL) {
 930                 zio_t *pio;
 931 
 932                 vd->vdev_cant_read |= !vps->vps_readable;
 933                 vd->vdev_cant_write |= !vps->vps_writeable;
 934 
 935                 if (vdev_readable(vd) &&
 936                     (vdev_writeable(vd) || !spa_writeable(spa))) {
 937                         zio->io_error = 0;
 938                 } else {
 939                         ASSERT(zio->io_error != 0);
 940                         zfs_ereport_post(FM_EREPORT_ZFS_PROBE_FAILURE,
 941                             spa, vd, NULL, 0, 0);
 942                         zio->io_error = ENXIO;
 943                 }
 944 
 945                 mutex_enter(&vd->vdev_probe_lock);
 946                 ASSERT(vd->vdev_probe_zio == zio);
 947                 vd->vdev_probe_zio = NULL;
 948                 mutex_exit(&vd->vdev_probe_lock);
 949 
 950                 while ((pio = zio_walk_parents(zio)) != NULL)
 951                         if (!vdev_accessible(vd, pio))
 952                                 pio->io_error = ENXIO;
 953 
 954                 kmem_free(vps, sizeof (*vps));
 955         }
 956 }
 957 
 958 /*
 959  * Determine whether this device is accessible by reading and writing
 960  * to several known locations: the pad regions of each vdev label
 961  * but the first (which we leave alone in case it contains a VTOC).
 962  */
 963 zio_t *
 964 vdev_probe(vdev_t *vd, zio_t *zio)
 965 {
 966         spa_t *spa = vd->vdev_spa;
 967         vdev_probe_stats_t *vps = NULL;
 968         zio_t *pio;
 969 
 970         ASSERT(vd->vdev_ops->vdev_op_leaf);
 971 
 972         /*
 973          * Don't probe the probe.
 974          */
 975         if (zio && (zio->io_flags & ZIO_FLAG_PROBE))
 976                 return (NULL);
 977 
 978         /*
 979          * To prevent 'probe storms' when a device fails, we create
 980          * just one probe i/o at a time.  All zios that want to probe
 981          * this vdev will become parents of the probe io.
 982          */
 983         mutex_enter(&vd->vdev_probe_lock);
 984 
 985         if ((pio = vd->vdev_probe_zio) == NULL) {
 986                 vps = kmem_zalloc(sizeof (*vps), KM_SLEEP);
 987 
 988                 vps->vps_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_PROBE |
 989                     ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_AGGREGATE |
 990                     ZIO_FLAG_TRYHARD;
 991 
 992                 if (spa_config_held(spa, SCL_ZIO, RW_WRITER)) {
 993                         /*
 994                          * vdev_cant_read and vdev_cant_write can only
 995                          * transition from TRUE to FALSE when we have the
 996                          * SCL_ZIO lock as writer; otherwise they can only
 997                          * transition from FALSE to TRUE.  This ensures that
 998                          * any zio looking at these values can assume that
 999                          * failures persist for the life of the I/O.  That's
1000                          * important because when a device has intermittent
1001                          * connectivity problems, we want to ensure that
1002                          * they're ascribed to the device (ENXIO) and not
1003                          * the zio (EIO).
1004                          *
1005                          * Since we hold SCL_ZIO as writer here, clear both
1006                          * values so the probe can reevaluate from first
1007                          * principles.
1008                          */
1009                         vps->vps_flags |= ZIO_FLAG_CONFIG_WRITER;
1010                         vd->vdev_cant_read = B_FALSE;
1011                         vd->vdev_cant_write = B_FALSE;
1012                 }
1013 
1014                 vd->vdev_probe_zio = pio = zio_null(NULL, spa, vd,
1015                     vdev_probe_done, vps,
1016                     vps->vps_flags | ZIO_FLAG_DONT_PROPAGATE);
1017 
1018                 /*
1019                  * We can't change the vdev state in this context, so we
1020                  * kick off an async task to do it on our behalf.
1021                  */
1022                 if (zio != NULL) {
1023                         vd->vdev_probe_wanted = B_TRUE;
1024                         spa_async_request(spa, SPA_ASYNC_PROBE);
1025                 }
1026         }
1027 
1028         if (zio != NULL)
1029                 zio_add_child(zio, pio);
1030 
1031         mutex_exit(&vd->vdev_probe_lock);
1032 
1033         if (vps == NULL) {
1034                 ASSERT(zio != NULL);
1035                 return (NULL);
1036         }
1037 
1038         for (int l = 1; l < VDEV_LABELS; l++) {
1039                 zio_nowait(zio_read_phys(pio, vd,
1040                     vdev_label_offset(vd->vdev_psize, l,
1041                     offsetof(vdev_label_t, vl_pad2)),
1042                     VDEV_PAD_SIZE, zio_buf_alloc(VDEV_PAD_SIZE),
1043                     ZIO_CHECKSUM_OFF, vdev_probe_done, vps,
1044                     ZIO_PRIORITY_SYNC_READ, vps->vps_flags, B_TRUE));
1045         }
1046 
1047         if (zio == NULL)
1048                 return (pio);
1049 
1050         zio_nowait(pio);
1051         return (NULL);
1052 }
1053 
1054 static void
1055 vdev_open_child(void *arg)
1056 {
1057         vdev_t *vd = arg;
1058 
1059         vd->vdev_open_thread = curthread;
1060         vd->vdev_open_error = vdev_open(vd);
1061         vd->vdev_open_thread = NULL;
1062 }
1063 
1064 boolean_t
1065 vdev_uses_zvols(vdev_t *vd)
1066 {
1067         if (vd->vdev_path && strncmp(vd->vdev_path, ZVOL_DIR,
1068             strlen(ZVOL_DIR)) == 0)
1069                 return (B_TRUE);
1070         for (int c = 0; c < vd->vdev_children; c++)
1071                 if (vdev_uses_zvols(vd->vdev_child[c]))
1072                         return (B_TRUE);
1073         return (B_FALSE);
1074 }
1075 
1076 void
1077 vdev_open_children(vdev_t *vd)
1078 {
1079         taskq_t *tq;
1080         int children = vd->vdev_children;
1081 
1082         /*
1083          * in order to handle pools on top of zvols, do the opens
1084          * in a single thread so that the same thread holds the
1085          * spa_namespace_lock
1086          */
1087         if (vdev_uses_zvols(vd)) {
1088                 for (int c = 0; c < children; c++)
1089                         vd->vdev_child[c]->vdev_open_error =
1090                             vdev_open(vd->vdev_child[c]);
1091                 return;
1092         }
1093         tq = taskq_create("vdev_open", children, minclsyspri,
1094             children, children, TASKQ_PREPOPULATE);
1095 
1096         for (int c = 0; c < children; c++)
1097                 VERIFY(taskq_dispatch(tq, vdev_open_child, vd->vdev_child[c],
1098                     TQ_SLEEP) != NULL);
1099 
1100         taskq_destroy(tq);
1101 }
1102 
1103 /*
1104  * Prepare a virtual device for access.
1105  */
1106 int
1107 vdev_open(vdev_t *vd)
1108 {
1109         spa_t *spa = vd->vdev_spa;
1110         int error;
1111         uint64_t osize = 0;
1112         uint64_t max_osize = 0;
1113         uint64_t asize, max_asize, psize;
1114         uint64_t ashift = 0;
1115 
1116         ASSERT(vd->vdev_open_thread == curthread ||
1117             spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
1118         ASSERT(vd->vdev_state == VDEV_STATE_CLOSED ||
1119             vd->vdev_state == VDEV_STATE_CANT_OPEN ||
1120             vd->vdev_state == VDEV_STATE_OFFLINE);
1121 
1122         vd->vdev_stat.vs_aux = VDEV_AUX_NONE;
1123         vd->vdev_cant_read = B_FALSE;
1124         vd->vdev_cant_write = B_FALSE;
1125         vd->vdev_min_asize = vdev_get_min_asize(vd);
1126 
1127         /*
1128          * If this vdev is not removed, check its fault status.  If it's
1129          * faulted, bail out of the open.
1130          */
1131         if (!vd->vdev_removed && vd->vdev_faulted) {
1132                 ASSERT(vd->vdev_children == 0);
1133                 ASSERT(vd->vdev_label_aux == VDEV_AUX_ERR_EXCEEDED ||
1134                     vd->vdev_label_aux == VDEV_AUX_EXTERNAL);
1135                 vdev_set_state(vd, B_TRUE, VDEV_STATE_FAULTED,
1136                     vd->vdev_label_aux);
1137                 return (ENXIO);
1138         } else if (vd->vdev_offline) {
1139                 ASSERT(vd->vdev_children == 0);
1140                 vdev_set_state(vd, B_TRUE, VDEV_STATE_OFFLINE, VDEV_AUX_NONE);
1141                 return (ENXIO);
1142         }
1143 
1144         error = vd->vdev_ops->vdev_op_open(vd, &osize, &max_osize, &ashift);
1145 
1146         /*
1147          * Reset the vdev_reopening flag so that we actually close
1148          * the vdev on error.
1149          */
1150         vd->vdev_reopening = B_FALSE;
1151         if (zio_injection_enabled && error == 0)
1152                 error = zio_handle_device_injection(vd, NULL, ENXIO);
1153 
1154         if (error) {
1155                 if (vd->vdev_removed &&
1156                     vd->vdev_stat.vs_aux != VDEV_AUX_OPEN_FAILED)
1157                         vd->vdev_removed = B_FALSE;
1158 
1159                 vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
1160                     vd->vdev_stat.vs_aux);
1161                 return (error);
1162         }
1163 
1164         vd->vdev_removed = B_FALSE;
1165 
1166         /*
1167          * Recheck the faulted flag now that we have confirmed that
1168          * the vdev is accessible.  If we're faulted, bail.
1169          */
1170         if (vd->vdev_faulted) {
1171                 ASSERT(vd->vdev_children == 0);
1172                 ASSERT(vd->vdev_label_aux == VDEV_AUX_ERR_EXCEEDED ||
1173                     vd->vdev_label_aux == VDEV_AUX_EXTERNAL);
1174                 vdev_set_state(vd, B_TRUE, VDEV_STATE_FAULTED,
1175                     vd->vdev_label_aux);
1176                 return (ENXIO);
1177         }
1178 
1179         if (vd->vdev_degraded) {
1180                 ASSERT(vd->vdev_children == 0);
1181                 vdev_set_state(vd, B_TRUE, VDEV_STATE_DEGRADED,
1182                     VDEV_AUX_ERR_EXCEEDED);
1183         } else {
1184                 vdev_set_state(vd, B_TRUE, VDEV_STATE_HEALTHY, 0);
1185         }
1186 
1187         /*
1188          * For hole or missing vdevs we just return success.
1189          */
1190         if (vd->vdev_ishole || vd->vdev_ops == &vdev_missing_ops)
1191                 return (0);
1192 
1193         for (int c = 0; c < vd->vdev_children; c++) {
1194                 if (vd->vdev_child[c]->vdev_state != VDEV_STATE_HEALTHY) {
1195                         vdev_set_state(vd, B_TRUE, VDEV_STATE_DEGRADED,
1196                             VDEV_AUX_NONE);
1197                         break;
1198                 }
1199         }
1200 
1201         osize = P2ALIGN(osize, (uint64_t)sizeof (vdev_label_t));
1202         max_osize = P2ALIGN(max_osize, (uint64_t)sizeof (vdev_label_t));
1203 
1204         if (vd->vdev_children == 0) {
1205                 if (osize < SPA_MINDEVSIZE) {
1206                         vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
1207                             VDEV_AUX_TOO_SMALL);
1208                         return (EOVERFLOW);
1209                 }
1210                 psize = osize;
1211                 asize = osize - (VDEV_LABEL_START_SIZE + VDEV_LABEL_END_SIZE);
1212                 max_asize = max_osize - (VDEV_LABEL_START_SIZE +
1213                     VDEV_LABEL_END_SIZE);
1214         } else {
1215                 if (vd->vdev_parent != NULL && osize < SPA_MINDEVSIZE -
1216                     (VDEV_LABEL_START_SIZE + VDEV_LABEL_END_SIZE)) {
1217                         vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
1218                             VDEV_AUX_TOO_SMALL);
1219                         return (EOVERFLOW);
1220                 }
1221                 psize = 0;
1222                 asize = osize;
1223                 max_asize = max_osize;
1224         }
1225 
1226         vd->vdev_psize = psize;
1227 
1228         /*
1229          * Make sure the allocatable size hasn't shrunk.
1230          */
1231         if (asize < vd->vdev_min_asize) {
1232                 vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
1233                     VDEV_AUX_BAD_LABEL);
1234                 return (EINVAL);
1235         }
1236 
1237         if (vd->vdev_asize == 0) {
1238                 /*
1239                  * This is the first-ever open, so use the computed values.
1240                  * For testing purposes, a higher ashift can be requested.
1241                  */
1242                 vd->vdev_asize = asize;
1243                 vd->vdev_max_asize = max_asize;
1244                 vd->vdev_ashift = MAX(ashift, vd->vdev_ashift);
1245         } else {
1246                 /*
1247                  * Detect if the alignment requirement has increased.
1248                  * We don't want to make the pool unavailable, just
1249                  * issue a warning instead.
1250                  */
1251                 if (ashift > vd->vdev_top->vdev_ashift &&
1252                     vd->vdev_ops->vdev_op_leaf) {
1253                         cmn_err(CE_WARN,
1254                             "Disk, '%s', has a block alignment that is "
1255                             "larger than the pool's alignment\n",
1256                             vd->vdev_path);
1257                 }
1258                 vd->vdev_max_asize = max_asize;
1259         }
1260 
1261         /*
1262          * If all children are healthy and the asize has increased,
1263          * then we've experienced dynamic LUN growth.  If automatic
1264          * expansion is enabled then use the additional space.
1265          */
1266         if (vd->vdev_state == VDEV_STATE_HEALTHY && asize > vd->vdev_asize &&
1267             (vd->vdev_expanding || spa->spa_autoexpand))
1268                 vd->vdev_asize = asize;
1269 
1270         vdev_set_min_asize(vd);
1271 
1272         /*
1273          * Ensure we can issue some IO before declaring the
1274          * vdev open for business.
1275          */
1276         if (vd->vdev_ops->vdev_op_leaf &&
1277             (error = zio_wait(vdev_probe(vd, NULL))) != 0) {
1278                 vdev_set_state(vd, B_TRUE, VDEV_STATE_FAULTED,
1279                     VDEV_AUX_ERR_EXCEEDED);
1280                 return (error);
1281         }
1282 
1283         /*
1284          * If a leaf vdev has a DTL, and seems healthy, then kick off a
1285          * resilver.  But don't do this if we are doing a reopen for a scrub,
1286          * since this would just restart the scrub we are already doing.
1287          */
1288         if (vd->vdev_ops->vdev_op_leaf && !spa->spa_scrub_reopen &&
1289             vdev_resilver_needed(vd, NULL, NULL))
1290                 spa_async_request(spa, SPA_ASYNC_RESILVER);
1291 
1292         return (0);
1293 }
1294 
1295 /*
1296  * Called once the vdevs are all opened, this routine validates the label
1297  * contents.  This needs to be done before vdev_load() so that we don't
1298  * inadvertently do repair I/Os to the wrong device.
1299  *
1300  * If 'strict' is false ignore the spa guid check. This is necessary because
1301  * if the machine crashed during a re-guid the new guid might have been written
1302  * to all of the vdev labels, but not the cached config. The strict check
1303  * will be performed when the pool is opened again using the mos config.
1304  *
1305  * This function will only return failure if one of the vdevs indicates that it
1306  * has since been destroyed or exported.  This is only possible if
1307  * /etc/zfs/zpool.cache was readonly at the time.  Otherwise, the vdev state
1308  * will be updated but the function will return 0.
1309  */
1310 int
1311 vdev_validate(vdev_t *vd, boolean_t strict)
1312 {
1313         spa_t *spa = vd->vdev_spa;
1314         nvlist_t *label;
1315         uint64_t guid = 0, top_guid;
1316         uint64_t state;
1317 
1318         for (int c = 0; c < vd->vdev_children; c++)
1319                 if (vdev_validate(vd->vdev_child[c], strict) != 0)
1320                         return (EBADF);
1321 
1322         /*
1323          * If the device has already failed, or was marked offline, don't do
1324          * any further validation.  Otherwise, label I/O will fail and we will
1325          * overwrite the previous state.
1326          */
1327         if (vd->vdev_ops->vdev_op_leaf && vdev_readable(vd)) {
1328                 uint64_t aux_guid = 0;
1329                 nvlist_t *nvl;
1330 
1331                 if ((label = vdev_label_read_config(vd)) == NULL) {
1332                         vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
1333                             VDEV_AUX_BAD_LABEL);
1334                         return (0);
1335                 }
1336 
1337                 /*
1338                  * Determine if this vdev has been split off into another
1339                  * pool.  If so, then refuse to open it.
1340                  */
1341                 if (nvlist_lookup_uint64(label, ZPOOL_CONFIG_SPLIT_GUID,
1342                     &aux_guid) == 0 && aux_guid == spa_guid(spa)) {
1343                         vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
1344                             VDEV_AUX_SPLIT_POOL);
1345                         nvlist_free(label);
1346                         return (0);
1347                 }
1348 
1349                 if (strict && (nvlist_lookup_uint64(label,
1350                     ZPOOL_CONFIG_POOL_GUID, &guid) != 0 ||
1351                     guid != spa_guid(spa))) {
1352                         vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
1353                             VDEV_AUX_CORRUPT_DATA);
1354                         nvlist_free(label);
1355                         return (0);
1356                 }
1357 
1358                 if (nvlist_lookup_nvlist(label, ZPOOL_CONFIG_VDEV_TREE, &nvl)
1359                     != 0 || nvlist_lookup_uint64(nvl, ZPOOL_CONFIG_ORIG_GUID,
1360                     &aux_guid) != 0)
1361                         aux_guid = 0;
1362 
1363                 /*
1364                  * If this vdev just became a top-level vdev because its
1365                  * sibling was detached, it will have adopted the parent's
1366                  * vdev guid -- but the label may or may not be on disk yet.
1367                  * Fortunately, either version of the label will have the
1368                  * same top guid, so if we're a top-level vdev, we can
1369                  * safely compare to that instead.
1370                  *
1371                  * If we split this vdev off instead, then we also check the
1372                  * original pool's guid.  We don't want to consider the vdev
1373                  * corrupt if it is partway through a split operation.
1374                  */
1375                 if (nvlist_lookup_uint64(label, ZPOOL_CONFIG_GUID,
1376                     &guid) != 0 ||
1377                     nvlist_lookup_uint64(label, ZPOOL_CONFIG_TOP_GUID,
1378                     &top_guid) != 0 ||
1379                     ((vd->vdev_guid != guid && vd->vdev_guid != aux_guid) &&
1380                     (vd->vdev_guid != top_guid || vd != vd->vdev_top))) {
1381                         vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
1382                             VDEV_AUX_CORRUPT_DATA);
1383                         nvlist_free(label);
1384                         return (0);
1385                 }
1386 
1387                 if (nvlist_lookup_uint64(label, ZPOOL_CONFIG_POOL_STATE,
1388                     &state) != 0) {
1389                         vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
1390                             VDEV_AUX_CORRUPT_DATA);
1391                         nvlist_free(label);
1392                         return (0);
1393                 }
1394 
1395                 nvlist_free(label);
1396 
1397                 /*
1398                  * If this is a verbatim import, no need to check the
1399                  * state of the pool.
1400                  */
1401                 if (!(spa->spa_import_flags & ZFS_IMPORT_VERBATIM) &&
1402                     spa_load_state(spa) == SPA_LOAD_OPEN &&
1403                     state != POOL_STATE_ACTIVE)
1404                         return (EBADF);
1405 
1406                 /*
1407                  * If we were able to open and validate a vdev that was
1408                  * previously marked permanently unavailable, clear that state
1409                  * now.
1410                  */
1411                 if (vd->vdev_not_present)
1412                         vd->vdev_not_present = 0;
1413         }
1414 
1415         return (0);
1416 }
1417 
1418 /*
1419  * Close a virtual device.
1420  */
1421 void
1422 vdev_close(vdev_t *vd)
1423 {
1424         spa_t *spa = vd->vdev_spa;
1425         vdev_t *pvd = vd->vdev_parent;
1426 
1427         ASSERT(spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
1428 
1429         /*
1430          * If our parent is reopening, then we are as well, unless we are
1431          * going offline.
1432          */
1433         if (pvd != NULL && pvd->vdev_reopening)
1434                 vd->vdev_reopening = (pvd->vdev_reopening && !vd->vdev_offline);
1435 
1436         vd->vdev_ops->vdev_op_close(vd);
1437 
1438         vdev_cache_purge(vd);
1439 
1440         /*
1441          * We record the previous state before we close it, so that if we are
1442          * doing a reopen(), we don't generate FMA ereports if we notice that
1443          * it's still faulted.
1444          */
1445         vd->vdev_prevstate = vd->vdev_state;
1446 
1447         if (vd->vdev_offline)
1448                 vd->vdev_state = VDEV_STATE_OFFLINE;
1449         else
1450                 vd->vdev_state = VDEV_STATE_CLOSED;
1451         vd->vdev_stat.vs_aux = VDEV_AUX_NONE;
1452 }
1453 
1454 void
1455 vdev_hold(vdev_t *vd)
1456 {
1457         spa_t *spa = vd->vdev_spa;
1458 
1459         ASSERT(spa_is_root(spa));
1460         if (spa->spa_state == POOL_STATE_UNINITIALIZED)
1461                 return;
1462 
1463         for (int c = 0; c < vd->vdev_children; c++)
1464                 vdev_hold(vd->vdev_child[c]);
1465 
1466         if (vd->vdev_ops->vdev_op_leaf)
1467                 vd->vdev_ops->vdev_op_hold(vd);
1468 }
1469 
1470 void
1471 vdev_rele(vdev_t *vd)
1472 {
1473         spa_t *spa = vd->vdev_spa;
1474 
1475         ASSERT(spa_is_root(spa));
1476         for (int c = 0; c < vd->vdev_children; c++)
1477                 vdev_rele(vd->vdev_child[c]);
1478 
1479         if (vd->vdev_ops->vdev_op_leaf)
1480                 vd->vdev_ops->vdev_op_rele(vd);
1481 }
1482 
1483 /*
1484  * Reopen all interior vdevs and any unopened leaves.  We don't actually
1485  * reopen leaf vdevs which had previously been opened as they might deadlock
1486  * on the spa_config_lock.  Instead we only obtain the leaf's physical size.
1487  * If the leaf has never been opened then open it, as usual.
1488  */
1489 void
1490 vdev_reopen(vdev_t *vd)
1491 {
1492         spa_t *spa = vd->vdev_spa;
1493 
1494         ASSERT(spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
1495 
1496         /* set the reopening flag unless we're taking the vdev offline */
1497         vd->vdev_reopening = !vd->vdev_offline;
1498         vdev_close(vd);
1499         (void) vdev_open(vd);
1500 
1501         /*
1502          * Call vdev_validate() here to make sure we have the same device.
1503          * Otherwise, a device with an invalid label could be successfully
1504          * opened in response to vdev_reopen().
1505          */
1506         if (vd->vdev_aux) {
1507                 (void) vdev_validate_aux(vd);
1508                 if (vdev_readable(vd) && vdev_writeable(vd) &&
1509                     vd->vdev_aux == &spa->spa_l2cache &&
1510                     !l2arc_vdev_present(vd))
1511                         l2arc_add_vdev(spa, vd);
1512         } else {
1513                 (void) vdev_validate(vd, B_TRUE);
1514         }
1515 
1516         /*
1517          * Reassess parent vdev's health.
1518          */
1519         vdev_propagate_state(vd);
1520 }
1521 
1522 int
1523 vdev_create(vdev_t *vd, uint64_t txg, boolean_t isreplacing)
1524 {
1525         int error;
1526 
1527         /*
1528          * Normally, partial opens (e.g. of a mirror) are allowed.
1529          * For a create, however, we want to fail the request if
1530          * there are any components we can't open.
1531          */
1532         error = vdev_open(vd);
1533 
1534         if (error || vd->vdev_state != VDEV_STATE_HEALTHY) {
1535                 vdev_close(vd);
1536                 return (error ? error : ENXIO);
1537         }
1538 
1539         /*
1540          * Recursively initialize all labels.
1541          */
1542         if ((error = vdev_label_init(vd, txg, isreplacing ?
1543             VDEV_LABEL_REPLACE : VDEV_LABEL_CREATE)) != 0) {
1544                 vdev_close(vd);
1545                 return (error);
1546         }
1547 
1548         return (0);
1549 }
1550 
1551 void
1552 vdev_metaslab_set_size(vdev_t *vd)
1553 {
1554         /*
1555          * Aim for roughly 200 metaslabs per vdev.
1556          */
1557         vd->vdev_ms_shift = highbit(vd->vdev_asize / 200);
1558         vd->vdev_ms_shift = MAX(vd->vdev_ms_shift, SPA_MAXBLOCKSHIFT);
1559 }
1560 
1561 void
1562 vdev_dirty(vdev_t *vd, int flags, void *arg, uint64_t txg)
1563 {
1564         ASSERT(vd == vd->vdev_top);
1565         ASSERT(!vd->vdev_ishole);
1566         ASSERT(ISP2(flags));
1567         ASSERT(spa_writeable(vd->vdev_spa));
1568 
1569         if (flags & VDD_METASLAB)
1570                 (void) txg_list_add(&vd->vdev_ms_list, arg, txg);
1571 
1572         if (flags & VDD_DTL)
1573                 (void) txg_list_add(&vd->vdev_dtl_list, arg, txg);
1574 
1575         (void) txg_list_add(&vd->vdev_spa->spa_vdev_txg_list, vd, txg);
1576 }
1577 
1578 /*
1579  * DTLs.
1580  *
1581  * A vdev's DTL (dirty time log) is the set of transaction groups for which
1582  * the vdev has less than perfect replication.  There are four kinds of DTL:
1583  *
1584  * DTL_MISSING: txgs for which the vdev has no valid copies of the data
1585  *
1586  * DTL_PARTIAL: txgs for which data is available, but not fully replicated
1587  *
1588  * DTL_SCRUB: the txgs that could not be repaired by the last scrub; upon
1589  *      scrub completion, DTL_SCRUB replaces DTL_MISSING in the range of
1590  *      txgs that was scrubbed.
1591  *
1592  * DTL_OUTAGE: txgs which cannot currently be read, whether due to
1593  *      persistent errors or just some device being offline.
1594  *      Unlike the other three, the DTL_OUTAGE map is not generally
1595  *      maintained; it's only computed when needed, typically to
1596  *      determine whether a device can be detached.
1597  *
1598  * For leaf vdevs, DTL_MISSING and DTL_PARTIAL are identical: the device
1599  * either has the data or it doesn't.
1600  *
1601  * For interior vdevs such as mirror and RAID-Z the picture is more complex.
1602  * A vdev's DTL_PARTIAL is the union of its children's DTL_PARTIALs, because
1603  * if any child is less than fully replicated, then so is its parent.
1604  * A vdev's DTL_MISSING is a modified union of its children's DTL_MISSINGs,
1605  * comprising only those txgs which appear in 'maxfaults' or more children;
1606  * those are the txgs we don't have enough replication to read.  For example,
1607  * double-parity RAID-Z can tolerate up to two missing devices (maxfaults == 2);
1608  * thus, its DTL_MISSING consists of the set of txgs that appear in more than
1609  * two child DTL_MISSING maps.
1610  *
1611  * It should be clear from the above that to compute the DTLs and outage maps
1612  * for all vdevs, it suffices to know just the leaf vdevs' DTL_MISSING maps.
1613  * Therefore, that is all we keep on disk.  When loading the pool, or after
1614  * a configuration change, we generate all other DTLs from first principles.
1615  */
1616 void
1617 vdev_dtl_dirty(vdev_t *vd, vdev_dtl_type_t t, uint64_t txg, uint64_t size)
1618 {
1619         space_map_t *sm = &vd->vdev_dtl[t];
1620 
1621         ASSERT(t < DTL_TYPES);
1622         ASSERT(vd != vd->vdev_spa->spa_root_vdev);
1623         ASSERT(spa_writeable(vd->vdev_spa));
1624 
1625         mutex_enter(sm->sm_lock);
1626         if (!space_map_contains(sm, txg, size))
1627                 space_map_add(sm, txg, size);
1628         mutex_exit(sm->sm_lock);
1629 }
1630 
1631 boolean_t
1632 vdev_dtl_contains(vdev_t *vd, vdev_dtl_type_t t, uint64_t txg, uint64_t size)
1633 {
1634         space_map_t *sm = &vd->vdev_dtl[t];
1635         boolean_t dirty = B_FALSE;
1636 
1637         ASSERT(t < DTL_TYPES);
1638         ASSERT(vd != vd->vdev_spa->spa_root_vdev);
1639 
1640         mutex_enter(sm->sm_lock);
1641         if (sm->sm_space != 0)
1642                 dirty = space_map_contains(sm, txg, size);
1643         mutex_exit(sm->sm_lock);
1644 
1645         return (dirty);
1646 }
1647 
1648 boolean_t
1649 vdev_dtl_empty(vdev_t *vd, vdev_dtl_type_t t)
1650 {
1651         space_map_t *sm = &vd->vdev_dtl[t];
1652         boolean_t empty;
1653 
1654         mutex_enter(sm->sm_lock);
1655         empty = (sm->sm_space == 0);
1656         mutex_exit(sm->sm_lock);
1657 
1658         return (empty);
1659 }
1660 
1661 /*
1662  * Reassess DTLs after a config change or scrub completion.
1663  */
1664 void
1665 vdev_dtl_reassess(vdev_t *vd, uint64_t txg, uint64_t scrub_txg, int scrub_done)
1666 {
1667         spa_t *spa = vd->vdev_spa;
1668         avl_tree_t reftree;
1669         int minref;
1670 
1671         ASSERT(spa_config_held(spa, SCL_ALL, RW_READER) != 0);
1672 
1673         for (int c = 0; c < vd->vdev_children; c++)
1674                 vdev_dtl_reassess(vd->vdev_child[c], txg,
1675                     scrub_txg, scrub_done);
1676 
1677         if (vd == spa->spa_root_vdev || vd->vdev_ishole || vd->vdev_aux)
1678                 return;
1679 
1680         if (vd->vdev_ops->vdev_op_leaf) {
1681                 dsl_scan_t *scn = spa->spa_dsl_pool->dp_scan;
1682 
1683                 mutex_enter(&vd->vdev_dtl_lock);
1684                 if (scrub_txg != 0 &&
1685                     (spa->spa_scrub_started ||
1686                     (scn && scn->scn_phys.scn_errors == 0))) {
1687                         /*
1688                          * We completed a scrub up to scrub_txg.  If we
1689                          * did it without rebooting, then the scrub dtl
1690                          * will be valid, so excise the old region and
1691                          * fold in the scrub dtl.  Otherwise, leave the
1692                          * dtl as-is if there was an error.
1693                          *
1694                          * There's little trick here: to excise the beginning
1695                          * of the DTL_MISSING map, we put it into a reference
1696                          * tree and then add a segment with refcnt -1 that
1697                          * covers the range [0, scrub_txg).  This means
1698                          * that each txg in that range has refcnt -1 or 0.
1699                          * We then add DTL_SCRUB with a refcnt of 2, so that
1700                          * entries in the range [0, scrub_txg) will have a
1701                          * positive refcnt -- either 1 or 2.  We then convert
1702                          * the reference tree into the new DTL_MISSING map.
1703                          */
1704                         space_map_ref_create(&reftree);
1705                         space_map_ref_add_map(&reftree,
1706                             &vd->vdev_dtl[DTL_MISSING], 1);
1707                         space_map_ref_add_seg(&reftree, 0, scrub_txg, -1);
1708                         space_map_ref_add_map(&reftree,
1709                             &vd->vdev_dtl[DTL_SCRUB], 2);
1710                         space_map_ref_generate_map(&reftree,
1711                             &vd->vdev_dtl[DTL_MISSING], 1);
1712                         space_map_ref_destroy(&reftree);
1713                 }
1714                 space_map_vacate(&vd->vdev_dtl[DTL_PARTIAL], NULL, NULL);
1715                 space_map_walk(&vd->vdev_dtl[DTL_MISSING],
1716                     space_map_add, &vd->vdev_dtl[DTL_PARTIAL]);
1717                 if (scrub_done)
1718                         space_map_vacate(&vd->vdev_dtl[DTL_SCRUB], NULL, NULL);
1719                 space_map_vacate(&vd->vdev_dtl[DTL_OUTAGE], NULL, NULL);
1720                 if (!vdev_readable(vd))
1721                         space_map_add(&vd->vdev_dtl[DTL_OUTAGE], 0, -1ULL);
1722                 else
1723                         space_map_walk(&vd->vdev_dtl[DTL_MISSING],
1724                             space_map_add, &vd->vdev_dtl[DTL_OUTAGE]);
1725                 mutex_exit(&vd->vdev_dtl_lock);
1726 
1727                 if (txg != 0)
1728                         vdev_dirty(vd->vdev_top, VDD_DTL, vd, txg);
1729                 return;
1730         }
1731 
1732         mutex_enter(&vd->vdev_dtl_lock);
1733         for (int t = 0; t < DTL_TYPES; t++) {
1734                 /* account for child's outage in parent's missing map */
1735                 int s = (t == DTL_MISSING) ? DTL_OUTAGE: t;
1736                 if (t == DTL_SCRUB)
1737                         continue;                       /* leaf vdevs only */
1738                 if (t == DTL_PARTIAL)
1739                         minref = 1;                     /* i.e. non-zero */
1740                 else if (vd->vdev_nparity != 0)
1741                         minref = vd->vdev_nparity + 1;       /* RAID-Z */
1742                 else
1743                         minref = vd->vdev_children;  /* any kind of mirror */
1744                 space_map_ref_create(&reftree);
1745                 for (int c = 0; c < vd->vdev_children; c++) {
1746                         vdev_t *cvd = vd->vdev_child[c];
1747                         mutex_enter(&cvd->vdev_dtl_lock);
1748                         space_map_ref_add_map(&reftree, &cvd->vdev_dtl[s], 1);
1749                         mutex_exit(&cvd->vdev_dtl_lock);
1750                 }
1751                 space_map_ref_generate_map(&reftree, &vd->vdev_dtl[t], minref);
1752                 space_map_ref_destroy(&reftree);
1753         }
1754         mutex_exit(&vd->vdev_dtl_lock);
1755 }
1756 
1757 static int
1758 vdev_dtl_load(vdev_t *vd)
1759 {
1760         spa_t *spa = vd->vdev_spa;
1761         space_map_obj_t *smo = &vd->vdev_dtl_smo;
1762         objset_t *mos = spa->spa_meta_objset;
1763         dmu_buf_t *db;
1764         int error;
1765 
1766         ASSERT(vd->vdev_children == 0);
1767 
1768         if (smo->smo_object == 0)
1769                 return (0);
1770 
1771         ASSERT(!vd->vdev_ishole);
1772 
1773         if ((error = dmu_bonus_hold(mos, smo->smo_object, FTAG, &db)) != 0)
1774                 return (error);
1775 
1776         ASSERT3U(db->db_size, >=, sizeof (*smo));
1777         bcopy(db->db_data, smo, sizeof (*smo));
1778         dmu_buf_rele(db, FTAG);
1779 
1780         mutex_enter(&vd->vdev_dtl_lock);
1781         error = space_map_load(&vd->vdev_dtl[DTL_MISSING],
1782             NULL, SM_ALLOC, smo, mos);
1783         mutex_exit(&vd->vdev_dtl_lock);
1784 
1785         return (error);
1786 }
1787 
1788 void
1789 vdev_dtl_sync(vdev_t *vd, uint64_t txg)
1790 {
1791         spa_t *spa = vd->vdev_spa;
1792         space_map_obj_t *smo = &vd->vdev_dtl_smo;
1793         space_map_t *sm = &vd->vdev_dtl[DTL_MISSING];
1794         objset_t *mos = spa->spa_meta_objset;
1795         space_map_t smsync;
1796         kmutex_t smlock;
1797         dmu_buf_t *db;
1798         dmu_tx_t *tx;
1799 
1800         ASSERT(!vd->vdev_ishole);
1801 
1802         tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg);
1803 
1804         if (vd->vdev_detached) {
1805                 if (smo->smo_object != 0) {
1806                         int err = dmu_object_free(mos, smo->smo_object, tx);
1807                         ASSERT3U(err, ==, 0);
1808                         smo->smo_object = 0;
1809                 }
1810                 dmu_tx_commit(tx);
1811                 return;
1812         }
1813 
1814         if (smo->smo_object == 0) {
1815                 ASSERT(smo->smo_objsize == 0);
1816                 ASSERT(smo->smo_alloc == 0);
1817                 smo->smo_object = dmu_object_alloc(mos,
1818                     DMU_OT_SPACE_MAP, 1 << SPACE_MAP_BLOCKSHIFT,
1819                     DMU_OT_SPACE_MAP_HEADER, sizeof (*smo), tx);
1820                 ASSERT(smo->smo_object != 0);
1821                 vdev_config_dirty(vd->vdev_top);
1822         }
1823 
1824         mutex_init(&smlock, NULL, MUTEX_DEFAULT, NULL);
1825 
1826         space_map_create(&smsync, sm->sm_start, sm->sm_size, sm->sm_shift,
1827             &smlock);
1828 
1829         mutex_enter(&smlock);
1830 
1831         mutex_enter(&vd->vdev_dtl_lock);
1832         space_map_walk(sm, space_map_add, &smsync);
1833         mutex_exit(&vd->vdev_dtl_lock);
1834 
1835         space_map_truncate(smo, mos, tx);
1836         space_map_sync(&smsync, SM_ALLOC, smo, mos, tx);
1837 
1838         space_map_destroy(&smsync);
1839 
1840         mutex_exit(&smlock);
1841         mutex_destroy(&smlock);
1842 
1843         VERIFY(0 == dmu_bonus_hold(mos, smo->smo_object, FTAG, &db));
1844         dmu_buf_will_dirty(db, tx);
1845         ASSERT3U(db->db_size, >=, sizeof (*smo));
1846         bcopy(smo, db->db_data, sizeof (*smo));
1847         dmu_buf_rele(db, FTAG);
1848 
1849         dmu_tx_commit(tx);
1850 }
1851 
1852 /*
1853  * Determine whether the specified vdev can be offlined/detached/removed
1854  * without losing data.
1855  */
1856 boolean_t
1857 vdev_dtl_required(vdev_t *vd)
1858 {
1859         spa_t *spa = vd->vdev_spa;
1860         vdev_t *tvd = vd->vdev_top;
1861         uint8_t cant_read = vd->vdev_cant_read;
1862         boolean_t required;
1863 
1864         ASSERT(spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
1865 
1866         if (vd == spa->spa_root_vdev || vd == tvd)
1867                 return (B_TRUE);
1868 
1869         /*
1870          * Temporarily mark the device as unreadable, and then determine
1871          * whether this results in any DTL outages in the top-level vdev.
1872          * If not, we can safely offline/detach/remove the device.
1873          */
1874         vd->vdev_cant_read = B_TRUE;
1875         vdev_dtl_reassess(tvd, 0, 0, B_FALSE);
1876         required = !vdev_dtl_empty(tvd, DTL_OUTAGE);
1877         vd->vdev_cant_read = cant_read;
1878         vdev_dtl_reassess(tvd, 0, 0, B_FALSE);
1879 
1880         if (!required && zio_injection_enabled)
1881                 required = !!zio_handle_device_injection(vd, NULL, ECHILD);
1882 
1883         return (required);
1884 }
1885 
1886 /*
1887  * Determine if resilver is needed, and if so the txg range.
1888  */
1889 boolean_t
1890 vdev_resilver_needed(vdev_t *vd, uint64_t *minp, uint64_t *maxp)
1891 {
1892         boolean_t needed = B_FALSE;
1893         uint64_t thismin = UINT64_MAX;
1894         uint64_t thismax = 0;
1895 
1896         if (vd->vdev_children == 0) {
1897                 mutex_enter(&vd->vdev_dtl_lock);
1898                 if (vd->vdev_dtl[DTL_MISSING].sm_space != 0 &&
1899                     vdev_writeable(vd)) {
1900                         space_seg_t *ss;
1901 
1902                         ss = avl_first(&vd->vdev_dtl[DTL_MISSING].sm_root);
1903                         thismin = ss->ss_start - 1;
1904                         ss = avl_last(&vd->vdev_dtl[DTL_MISSING].sm_root);
1905                         thismax = ss->ss_end;
1906                         needed = B_TRUE;
1907                 }
1908                 mutex_exit(&vd->vdev_dtl_lock);
1909         } else {
1910                 for (int c = 0; c < vd->vdev_children; c++) {
1911                         vdev_t *cvd = vd->vdev_child[c];
1912                         uint64_t cmin, cmax;
1913 
1914                         if (vdev_resilver_needed(cvd, &cmin, &cmax)) {
1915                                 thismin = MIN(thismin, cmin);
1916                                 thismax = MAX(thismax, cmax);
1917                                 needed = B_TRUE;
1918                         }
1919                 }
1920         }
1921 
1922         if (needed && minp) {
1923                 *minp = thismin;
1924                 *maxp = thismax;
1925         }
1926         return (needed);
1927 }
1928 
1929 void
1930 vdev_load(vdev_t *vd)
1931 {
1932         /*
1933          * Recursively load all children.
1934          */
1935         for (int c = 0; c < vd->vdev_children; c++)
1936                 vdev_load(vd->vdev_child[c]);
1937 
1938         /*
1939          * If this is a top-level vdev, initialize its metaslabs.
1940          */
1941         if (vd == vd->vdev_top && !vd->vdev_ishole &&
1942             (vd->vdev_ashift == 0 || vd->vdev_asize == 0 ||
1943             vdev_metaslab_init(vd, 0) != 0))
1944                 vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
1945                     VDEV_AUX_CORRUPT_DATA);
1946 
1947         /*
1948          * If this is a leaf vdev, load its DTL.
1949          */
1950         if (vd->vdev_ops->vdev_op_leaf && vdev_dtl_load(vd) != 0)
1951                 vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
1952                     VDEV_AUX_CORRUPT_DATA);
1953 }
1954 
1955 /*
1956  * The special vdev case is used for hot spares and l2cache devices.  Its
1957  * sole purpose it to set the vdev state for the associated vdev.  To do this,
1958  * we make sure that we can open the underlying device, then try to read the
1959  * label, and make sure that the label is sane and that it hasn't been
1960  * repurposed to another pool.
1961  */
1962 int
1963 vdev_validate_aux(vdev_t *vd)
1964 {
1965         nvlist_t *label;
1966         uint64_t guid, version;
1967         uint64_t state;
1968 
1969         if (!vdev_readable(vd))
1970                 return (0);
1971 
1972         if ((label = vdev_label_read_config(vd)) == NULL) {
1973                 vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
1974                     VDEV_AUX_CORRUPT_DATA);
1975                 return (-1);
1976         }
1977 
1978         if (nvlist_lookup_uint64(label, ZPOOL_CONFIG_VERSION, &version) != 0 ||
1979             version > SPA_VERSION ||
1980             nvlist_lookup_uint64(label, ZPOOL_CONFIG_GUID, &guid) != 0 ||
1981             guid != vd->vdev_guid ||
1982             nvlist_lookup_uint64(label, ZPOOL_CONFIG_POOL_STATE, &state) != 0) {
1983                 vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
1984                     VDEV_AUX_CORRUPT_DATA);
1985                 nvlist_free(label);
1986                 return (-1);
1987         }
1988 
1989         /*
1990          * We don't actually check the pool state here.  If it's in fact in
1991          * use by another pool, we update this fact on the fly when requested.
1992          */
1993         nvlist_free(label);
1994         return (0);
1995 }
1996 
1997 void
1998 vdev_remove(vdev_t *vd, uint64_t txg)
1999 {
2000         spa_t *spa = vd->vdev_spa;
2001         objset_t *mos = spa->spa_meta_objset;
2002         dmu_tx_t *tx;
2003 
2004         tx = dmu_tx_create_assigned(spa_get_dsl(spa), txg);
2005 
2006         if (vd->vdev_dtl_smo.smo_object) {
2007                 ASSERT3U(vd->vdev_dtl_smo.smo_alloc, ==, 0);
2008                 (void) dmu_object_free(mos, vd->vdev_dtl_smo.smo_object, tx);
2009                 vd->vdev_dtl_smo.smo_object = 0;
2010         }
2011 
2012         if (vd->vdev_ms != NULL) {
2013                 for (int m = 0; m < vd->vdev_ms_count; m++) {
2014                         metaslab_t *msp = vd->vdev_ms[m];
2015 
2016                         if (msp == NULL || msp->ms_smo.smo_object == 0)
2017                                 continue;
2018 
2019                         ASSERT3U(msp->ms_smo.smo_alloc, ==, 0);
2020                         (void) dmu_object_free(mos, msp->ms_smo.smo_object, tx);
2021                         msp->ms_smo.smo_object = 0;
2022                 }
2023         }
2024 
2025         if (vd->vdev_ms_array) {
2026                 (void) dmu_object_free(mos, vd->vdev_ms_array, tx);
2027                 vd->vdev_ms_array = 0;
2028                 vd->vdev_ms_shift = 0;
2029         }
2030         dmu_tx_commit(tx);
2031 }
2032 
2033 void
2034 vdev_sync_done(vdev_t *vd, uint64_t txg)
2035 {
2036         metaslab_t *msp;
2037         boolean_t reassess = !txg_list_empty(&vd->vdev_ms_list, TXG_CLEAN(txg));
2038 
2039         ASSERT(!vd->vdev_ishole);
2040 
2041         while (msp = txg_list_remove(&vd->vdev_ms_list, TXG_CLEAN(txg)))
2042                 metaslab_sync_done(msp, txg);
2043 
2044         if (reassess)
2045                 metaslab_sync_reassess(vd->vdev_mg);
2046 }
2047 
2048 void
2049 vdev_sync(vdev_t *vd, uint64_t txg)
2050 {
2051         spa_t *spa = vd->vdev_spa;
2052         vdev_t *lvd;
2053         metaslab_t *msp;
2054         dmu_tx_t *tx;
2055 
2056         ASSERT(!vd->vdev_ishole);
2057 
2058         if (vd->vdev_ms_array == 0 && vd->vdev_ms_shift != 0) {
2059                 ASSERT(vd == vd->vdev_top);
2060                 tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg);
2061                 vd->vdev_ms_array = dmu_object_alloc(spa->spa_meta_objset,
2062                     DMU_OT_OBJECT_ARRAY, 0, DMU_OT_NONE, 0, tx);
2063                 ASSERT(vd->vdev_ms_array != 0);
2064                 vdev_config_dirty(vd);
2065                 dmu_tx_commit(tx);
2066         }
2067 
2068         /*
2069          * Remove the metadata associated with this vdev once it's empty.
2070          */
2071         if (vd->vdev_stat.vs_alloc == 0 && vd->vdev_removing)
2072                 vdev_remove(vd, txg);
2073 
2074         while ((msp = txg_list_remove(&vd->vdev_ms_list, txg)) != NULL) {
2075                 metaslab_sync(msp, txg);
2076                 (void) txg_list_add(&vd->vdev_ms_list, msp, TXG_CLEAN(txg));
2077         }
2078 
2079         while ((lvd = txg_list_remove(&vd->vdev_dtl_list, txg)) != NULL)
2080                 vdev_dtl_sync(lvd, txg);
2081 
2082         (void) txg_list_add(&spa->spa_vdev_txg_list, vd, TXG_CLEAN(txg));
2083 }
2084 
2085 uint64_t
2086 vdev_psize_to_asize(vdev_t *vd, uint64_t psize)
2087 {
2088         return (vd->vdev_ops->vdev_op_asize(vd, psize));
2089 }
2090 
2091 /*
2092  * Mark the given vdev faulted.  A faulted vdev behaves as if the device could
2093  * not be opened, and no I/O is attempted.
2094  */
2095 int
2096 vdev_fault(spa_t *spa, uint64_t guid, vdev_aux_t aux)
2097 {
2098         vdev_t *vd, *tvd;
2099 
2100         spa_vdev_state_enter(spa, SCL_NONE);
2101 
2102         if ((vd = spa_lookup_by_guid(spa, guid, B_TRUE)) == NULL)
2103                 return (spa_vdev_state_exit(spa, NULL, ENODEV));
2104 
2105         if (!vd->vdev_ops->vdev_op_leaf)
2106                 return (spa_vdev_state_exit(spa, NULL, ENOTSUP));
2107 
2108         tvd = vd->vdev_top;
2109 
2110         /*
2111          * We don't directly use the aux state here, but if we do a
2112          * vdev_reopen(), we need this value to be present to remember why we
2113          * were faulted.
2114          */
2115         vd->vdev_label_aux = aux;
2116 
2117         /*
2118          * Faulted state takes precedence over degraded.
2119          */
2120         vd->vdev_delayed_close = B_FALSE;
2121         vd->vdev_faulted = 1ULL;
2122         vd->vdev_degraded = 0ULL;
2123         vdev_set_state(vd, B_FALSE, VDEV_STATE_FAULTED, aux);
2124 
2125         /*
2126          * If this device has the only valid copy of the data, then
2127          * back off and simply mark the vdev as degraded instead.
2128          */
2129         if (!tvd->vdev_islog && vd->vdev_aux == NULL && vdev_dtl_required(vd)) {
2130                 vd->vdev_degraded = 1ULL;
2131                 vd->vdev_faulted = 0ULL;
2132 
2133                 /*
2134                  * If we reopen the device and it's not dead, only then do we
2135                  * mark it degraded.
2136                  */
2137                 vdev_reopen(tvd);
2138 
2139                 if (vdev_readable(vd))
2140                         vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED, aux);
2141         }
2142 
2143         return (spa_vdev_state_exit(spa, vd, 0));
2144 }
2145 
2146 /*
2147  * Mark the given vdev degraded.  A degraded vdev is purely an indication to the
2148  * user that something is wrong.  The vdev continues to operate as normal as far
2149  * as I/O is concerned.
2150  */
2151 int
2152 vdev_degrade(spa_t *spa, uint64_t guid, vdev_aux_t aux)
2153 {
2154         vdev_t *vd;
2155 
2156         spa_vdev_state_enter(spa, SCL_NONE);
2157 
2158         if ((vd = spa_lookup_by_guid(spa, guid, B_TRUE)) == NULL)
2159                 return (spa_vdev_state_exit(spa, NULL, ENODEV));
2160 
2161         if (!vd->vdev_ops->vdev_op_leaf)
2162                 return (spa_vdev_state_exit(spa, NULL, ENOTSUP));
2163 
2164         /*
2165          * If the vdev is already faulted, then don't do anything.
2166          */
2167         if (vd->vdev_faulted || vd->vdev_degraded)
2168                 return (spa_vdev_state_exit(spa, NULL, 0));
2169 
2170         vd->vdev_degraded = 1ULL;
2171         if (!vdev_is_dead(vd))
2172                 vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED,
2173                     aux);
2174 
2175         return (spa_vdev_state_exit(spa, vd, 0));
2176 }
2177 
2178 /*
2179  * Online the given vdev.  If 'unspare' is set, it implies two things.  First,
2180  * any attached spare device should be detached when the device finishes
2181  * resilvering.  Second, the online should be treated like a 'test' online case,
2182  * so no FMA events are generated if the device fails to open.
2183  */
2184 int
2185 vdev_online(spa_t *spa, uint64_t guid, uint64_t flags, vdev_state_t *newstate)
2186 {
2187         vdev_t *vd, *tvd, *pvd, *rvd = spa->spa_root_vdev;
2188 
2189         spa_vdev_state_enter(spa, SCL_NONE);
2190 
2191         if ((vd = spa_lookup_by_guid(spa, guid, B_TRUE)) == NULL)
2192                 return (spa_vdev_state_exit(spa, NULL, ENODEV));
2193 
2194         if (!vd->vdev_ops->vdev_op_leaf)
2195                 return (spa_vdev_state_exit(spa, NULL, ENOTSUP));
2196 
2197         tvd = vd->vdev_top;
2198         vd->vdev_offline = B_FALSE;
2199         vd->vdev_tmpoffline = B_FALSE;
2200         vd->vdev_checkremove = !!(flags & ZFS_ONLINE_CHECKREMOVE);
2201         vd->vdev_forcefault = !!(flags & ZFS_ONLINE_FORCEFAULT);
2202 
2203         /* XXX - L2ARC 1.0 does not support expansion */
2204         if (!vd->vdev_aux) {
2205                 for (pvd = vd; pvd != rvd; pvd = pvd->vdev_parent)
2206                         pvd->vdev_expanding = !!(flags & ZFS_ONLINE_EXPAND);
2207         }
2208 
2209         vdev_reopen(tvd);
2210         vd->vdev_checkremove = vd->vdev_forcefault = B_FALSE;
2211 
2212         if (!vd->vdev_aux) {
2213                 for (pvd = vd; pvd != rvd; pvd = pvd->vdev_parent)
2214                         pvd->vdev_expanding = B_FALSE;
2215         }
2216 
2217         if (newstate)
2218                 *newstate = vd->vdev_state;
2219         if ((flags & ZFS_ONLINE_UNSPARE) &&
2220             !vdev_is_dead(vd) && vd->vdev_parent &&
2221             vd->vdev_parent->vdev_ops == &vdev_spare_ops &&
2222             vd->vdev_parent->vdev_child[0] == vd)
2223                 vd->vdev_unspare = B_TRUE;
2224 
2225         if ((flags & ZFS_ONLINE_EXPAND) || spa->spa_autoexpand) {
2226 
2227                 /* XXX - L2ARC 1.0 does not support expansion */
2228                 if (vd->vdev_aux)
2229                         return (spa_vdev_state_exit(spa, vd, ENOTSUP));
2230                 spa_async_request(spa, SPA_ASYNC_CONFIG_UPDATE);
2231         }
2232         return (spa_vdev_state_exit(spa, vd, 0));
2233 }
2234 
2235 static int
2236 vdev_offline_locked(spa_t *spa, uint64_t guid, uint64_t flags)
2237 {
2238         vdev_t *vd, *tvd;
2239         int error = 0;
2240         uint64_t generation;
2241         metaslab_group_t *mg;
2242 
2243 top:
2244         spa_vdev_state_enter(spa, SCL_ALLOC);
2245 
2246         if ((vd = spa_lookup_by_guid(spa, guid, B_TRUE)) == NULL)
2247                 return (spa_vdev_state_exit(spa, NULL, ENODEV));
2248 
2249         if (!vd->vdev_ops->vdev_op_leaf)
2250                 return (spa_vdev_state_exit(spa, NULL, ENOTSUP));
2251 
2252         tvd = vd->vdev_top;
2253         mg = tvd->vdev_mg;
2254         generation = spa->spa_config_generation + 1;
2255 
2256         /*
2257          * If the device isn't already offline, try to offline it.
2258          */
2259         if (!vd->vdev_offline) {
2260                 /*
2261                  * If this device has the only valid copy of some data,
2262                  * don't allow it to be offlined. Log devices are always
2263                  * expendable.
2264                  */
2265                 if (!tvd->vdev_islog && vd->vdev_aux == NULL &&
2266                     vdev_dtl_required(vd))
2267                         return (spa_vdev_state_exit(spa, NULL, EBUSY));
2268 
2269                 /*
2270                  * If the top-level is a slog and it has had allocations
2271                  * then proceed.  We check that the vdev's metaslab group
2272                  * is not NULL since it's possible that we may have just
2273                  * added this vdev but not yet initialized its metaslabs.
2274                  */
2275                 if (tvd->vdev_islog && mg != NULL) {
2276                         /*
2277                          * Prevent any future allocations.
2278                          */
2279                         metaslab_group_passivate(mg);
2280                         (void) spa_vdev_state_exit(spa, vd, 0);
2281 
2282                         error = spa_offline_log(spa);
2283 
2284                         spa_vdev_state_enter(spa, SCL_ALLOC);
2285 
2286                         /*
2287                          * Check to see if the config has changed.
2288                          */
2289                         if (error || generation != spa->spa_config_generation) {
2290                                 metaslab_group_activate(mg);
2291                                 if (error)
2292                                         return (spa_vdev_state_exit(spa,
2293                                             vd, error));
2294                                 (void) spa_vdev_state_exit(spa, vd, 0);
2295                                 goto top;
2296                         }
2297                         ASSERT3U(tvd->vdev_stat.vs_alloc, ==, 0);
2298                 }
2299 
2300                 /*
2301                  * Offline this device and reopen its top-level vdev.
2302                  * If the top-level vdev is a log device then just offline
2303                  * it. Otherwise, if this action results in the top-level
2304                  * vdev becoming unusable, undo it and fail the request.
2305                  */
2306                 vd->vdev_offline = B_TRUE;
2307                 vdev_reopen(tvd);
2308 
2309                 if (!tvd->vdev_islog && vd->vdev_aux == NULL &&
2310                     vdev_is_dead(tvd)) {
2311                         vd->vdev_offline = B_FALSE;
2312                         vdev_reopen(tvd);
2313                         return (spa_vdev_state_exit(spa, NULL, EBUSY));
2314                 }
2315 
2316                 /*
2317                  * Add the device back into the metaslab rotor so that
2318                  * once we online the device it's open for business.
2319                  */
2320                 if (tvd->vdev_islog && mg != NULL)
2321                         metaslab_group_activate(mg);
2322         }
2323 
2324         vd->vdev_tmpoffline = !!(flags & ZFS_OFFLINE_TEMPORARY);
2325 
2326         return (spa_vdev_state_exit(spa, vd, 0));
2327 }
2328 
2329 int
2330 vdev_offline(spa_t *spa, uint64_t guid, uint64_t flags)
2331 {
2332         int error;
2333 
2334         mutex_enter(&spa->spa_vdev_top_lock);
2335         error = vdev_offline_locked(spa, guid, flags);
2336         mutex_exit(&spa->spa_vdev_top_lock);
2337 
2338         return (error);
2339 }
2340 
2341 /*
2342  * Clear the error counts associated with this vdev.  Unlike vdev_online() and
2343  * vdev_offline(), we assume the spa config is locked.  We also clear all
2344  * children.  If 'vd' is NULL, then the user wants to clear all vdevs.
2345  */
2346 void
2347 vdev_clear(spa_t *spa, vdev_t *vd)
2348 {
2349         vdev_t *rvd = spa->spa_root_vdev;
2350 
2351         ASSERT(spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
2352 
2353         if (vd == NULL)
2354                 vd = rvd;
2355 
2356         vd->vdev_stat.vs_read_errors = 0;
2357         vd->vdev_stat.vs_write_errors = 0;
2358         vd->vdev_stat.vs_checksum_errors = 0;
2359 
2360         for (int c = 0; c < vd->vdev_children; c++)
2361                 vdev_clear(spa, vd->vdev_child[c]);
2362 
2363         /*
2364          * If we're in the FAULTED state or have experienced failed I/O, then
2365          * clear the persistent state and attempt to reopen the device.  We
2366          * also mark the vdev config dirty, so that the new faulted state is
2367          * written out to disk.
2368          */
2369         if (vd->vdev_faulted || vd->vdev_degraded ||
2370             !vdev_readable(vd) || !vdev_writeable(vd)) {
2371 
2372                 /*
2373                  * When reopening in reponse to a clear event, it may be due to
2374                  * a fmadm repair request.  In this case, if the device is
2375                  * still broken, we want to still post the ereport again.
2376                  */
2377                 vd->vdev_forcefault = B_TRUE;
2378 
2379                 vd->vdev_faulted = vd->vdev_degraded = 0ULL;
2380                 vd->vdev_cant_read = B_FALSE;
2381                 vd->vdev_cant_write = B_FALSE;
2382 
2383                 vdev_reopen(vd == rvd ? rvd : vd->vdev_top);
2384 
2385                 vd->vdev_forcefault = B_FALSE;
2386 
2387                 if (vd != rvd && vdev_writeable(vd->vdev_top))
2388                         vdev_state_dirty(vd->vdev_top);
2389 
2390                 if (vd->vdev_aux == NULL && !vdev_is_dead(vd))
2391                         spa_async_request(spa, SPA_ASYNC_RESILVER);
2392 
2393                 spa_event_notify(spa, vd, ESC_ZFS_VDEV_CLEAR);
2394         }
2395 
2396         /*
2397          * When clearing a FMA-diagnosed fault, we always want to
2398          * unspare the device, as we assume that the original spare was
2399          * done in response to the FMA fault.
2400          */
2401         if (!vdev_is_dead(vd) && vd->vdev_parent != NULL &&
2402             vd->vdev_parent->vdev_ops == &vdev_spare_ops &&
2403             vd->vdev_parent->vdev_child[0] == vd)
2404                 vd->vdev_unspare = B_TRUE;
2405 }
2406 
2407 boolean_t
2408 vdev_is_dead(vdev_t *vd)
2409 {
2410         /*
2411          * Holes and missing devices are always considered "dead".
2412          * This simplifies the code since we don't have to check for
2413          * these types of devices in the various code paths.
2414          * Instead we rely on the fact that we skip over dead devices
2415          * before issuing I/O to them.
2416          */
2417         return (vd->vdev_state < VDEV_STATE_DEGRADED || vd->vdev_ishole ||
2418             vd->vdev_ops == &vdev_missing_ops);
2419 }
2420 
2421 boolean_t
2422 vdev_readable(vdev_t *vd)
2423 {
2424         return (!vdev_is_dead(vd) && !vd->vdev_cant_read);
2425 }
2426 
2427 boolean_t
2428 vdev_writeable(vdev_t *vd)
2429 {
2430         return (!vdev_is_dead(vd) && !vd->vdev_cant_write);
2431 }
2432 
2433 boolean_t
2434 vdev_allocatable(vdev_t *vd)
2435 {
2436         uint64_t state = vd->vdev_state;
2437 
2438         /*
2439          * We currently allow allocations from vdevs which may be in the
2440          * process of reopening (i.e. VDEV_STATE_CLOSED). If the device
2441          * fails to reopen then we'll catch it later when we're holding
2442          * the proper locks.  Note that we have to get the vdev state
2443          * in a local variable because although it changes atomically,
2444          * we're asking two separate questions about it.
2445          */
2446         return (!(state < VDEV_STATE_DEGRADED && state != VDEV_STATE_CLOSED) &&
2447             !vd->vdev_cant_write && !vd->vdev_ishole);
2448 }
2449 
2450 boolean_t
2451 vdev_accessible(vdev_t *vd, zio_t *zio)
2452 {
2453         ASSERT(zio->io_vd == vd);
2454 
2455         if (vdev_is_dead(vd) || vd->vdev_remove_wanted)
2456                 return (B_FALSE);
2457 
2458         if (zio->io_type == ZIO_TYPE_READ)
2459                 return (!vd->vdev_cant_read);
2460 
2461         if (zio->io_type == ZIO_TYPE_WRITE)
2462                 return (!vd->vdev_cant_write);
2463 
2464         return (B_TRUE);
2465 }
2466 
2467 /*
2468  * Get statistics for the given vdev.
2469  */
2470 void
2471 vdev_get_stats(vdev_t *vd, vdev_stat_t *vs)
2472 {
2473         vdev_t *rvd = vd->vdev_spa->spa_root_vdev;
2474 
2475         mutex_enter(&vd->vdev_stat_lock);
2476         bcopy(&vd->vdev_stat, vs, sizeof (*vs));
2477         vs->vs_timestamp = gethrtime() - vs->vs_timestamp;
2478         vs->vs_state = vd->vdev_state;
2479         vs->vs_rsize = vdev_get_min_asize(vd);
2480         if (vd->vdev_ops->vdev_op_leaf)
2481                 vs->vs_rsize += VDEV_LABEL_START_SIZE + VDEV_LABEL_END_SIZE;
2482         vs->vs_esize = vd->vdev_max_asize - vd->vdev_asize;
2483         mutex_exit(&vd->vdev_stat_lock);
2484 
2485         /*
2486          * If we're getting stats on the root vdev, aggregate the I/O counts
2487          * over all top-level vdevs (i.e. the direct children of the root).
2488          */
2489         if (vd == rvd) {
2490                 for (int c = 0; c < rvd->vdev_children; c++) {
2491                         vdev_t *cvd = rvd->vdev_child[c];
2492                         vdev_stat_t *cvs = &cvd->vdev_stat;
2493 
2494                         mutex_enter(&vd->vdev_stat_lock);
2495                         for (int t = 0; t < ZIO_TYPES; t++) {
2496                                 vs->vs_ops[t] += cvs->vs_ops[t];
2497                                 vs->vs_bytes[t] += cvs->vs_bytes[t];
2498                         }
2499                         cvs->vs_scan_removing = cvd->vdev_removing;
2500                         mutex_exit(&vd->vdev_stat_lock);
2501                 }
2502         }
2503 }
2504 
2505 void
2506 vdev_clear_stats(vdev_t *vd)
2507 {
2508         mutex_enter(&vd->vdev_stat_lock);
2509         vd->vdev_stat.vs_space = 0;
2510         vd->vdev_stat.vs_dspace = 0;
2511         vd->vdev_stat.vs_alloc = 0;
2512         mutex_exit(&vd->vdev_stat_lock);
2513 }
2514 
2515 void
2516 vdev_scan_stat_init(vdev_t *vd)
2517 {
2518         vdev_stat_t *vs = &vd->vdev_stat;
2519 
2520         for (int c = 0; c < vd->vdev_children; c++)
2521                 vdev_scan_stat_init(vd->vdev_child[c]);
2522 
2523         mutex_enter(&vd->vdev_stat_lock);
2524         vs->vs_scan_processed = 0;
2525         mutex_exit(&vd->vdev_stat_lock);
2526 }
2527 
2528 void
2529 vdev_stat_update(zio_t *zio, uint64_t psize)
2530 {
2531         spa_t *spa = zio->io_spa;
2532         vdev_t *rvd = spa->spa_root_vdev;
2533         vdev_t *vd = zio->io_vd ? zio->io_vd : rvd;
2534         vdev_t *pvd;
2535         uint64_t txg = zio->io_txg;
2536         vdev_stat_t *vs = &vd->vdev_stat;
2537         zio_type_t type = zio->io_type;
2538         int flags = zio->io_flags;
2539 
2540         /*
2541          * If this i/o is a gang leader, it didn't do any actual work.
2542          */
2543         if (zio->io_gang_tree)
2544                 return;
2545 
2546         if (zio->io_error == 0) {
2547                 /*
2548                  * If this is a root i/o, don't count it -- we've already
2549                  * counted the top-level vdevs, and vdev_get_stats() will
2550                  * aggregate them when asked.  This reduces contention on
2551                  * the root vdev_stat_lock and implicitly handles blocks
2552                  * that compress away to holes, for which there is no i/o.
2553                  * (Holes never create vdev children, so all the counters
2554                  * remain zero, which is what we want.)
2555                  *
2556                  * Note: this only applies to successful i/o (io_error == 0)
2557                  * because unlike i/o counts, errors are not additive.
2558                  * When reading a ditto block, for example, failure of
2559                  * one top-level vdev does not imply a root-level error.
2560                  */
2561                 if (vd == rvd)
2562                         return;
2563 
2564                 ASSERT(vd == zio->io_vd);
2565 
2566                 if (flags & ZIO_FLAG_IO_BYPASS)
2567                         return;
2568 
2569                 mutex_enter(&vd->vdev_stat_lock);
2570 
2571                 if (flags & ZIO_FLAG_IO_REPAIR) {
2572                         if (flags & ZIO_FLAG_SCAN_THREAD) {
2573                                 dsl_scan_phys_t *scn_phys =
2574                                     &spa->spa_dsl_pool->dp_scan->scn_phys;
2575                                 uint64_t *processed = &scn_phys->scn_processed;
2576 
2577                                 /* XXX cleanup? */
2578                                 if (vd->vdev_ops->vdev_op_leaf)
2579                                         atomic_add_64(processed, psize);
2580                                 vs->vs_scan_processed += psize;
2581                         }
2582 
2583                         if (flags & ZIO_FLAG_SELF_HEAL)
2584                                 vs->vs_self_healed += psize;
2585                 }
2586 
2587                 vs->vs_ops[type]++;
2588                 vs->vs_bytes[type] += psize;
2589 
2590                 mutex_exit(&vd->vdev_stat_lock);
2591                 return;
2592         }
2593 
2594         if (flags & ZIO_FLAG_SPECULATIVE)
2595                 return;
2596 
2597         /*
2598          * If this is an I/O error that is going to be retried, then ignore the
2599          * error.  Otherwise, the user may interpret B_FAILFAST I/O errors as
2600          * hard errors, when in reality they can happen for any number of
2601          * innocuous reasons (bus resets, MPxIO link failure, etc).
2602          */
2603         if (zio->io_error == EIO &&
2604             !(zio->io_flags & ZIO_FLAG_IO_RETRY))
2605                 return;
2606 
2607         /*
2608          * Intent logs writes won't propagate their error to the root
2609          * I/O so don't mark these types of failures as pool-level
2610          * errors.
2611          */
2612         if (zio->io_vd == NULL && (zio->io_flags & ZIO_FLAG_DONT_PROPAGATE))
2613                 return;
2614 
2615         mutex_enter(&vd->vdev_stat_lock);
2616         if (type == ZIO_TYPE_READ && !vdev_is_dead(vd)) {
2617                 if (zio->io_error == ECKSUM)
2618                         vs->vs_checksum_errors++;
2619                 else
2620                         vs->vs_read_errors++;
2621         }
2622         if (type == ZIO_TYPE_WRITE && !vdev_is_dead(vd))
2623                 vs->vs_write_errors++;
2624         mutex_exit(&vd->vdev_stat_lock);
2625 
2626         if (type == ZIO_TYPE_WRITE && txg != 0 &&
2627             (!(flags & ZIO_FLAG_IO_REPAIR) ||
2628             (flags & ZIO_FLAG_SCAN_THREAD) ||
2629             spa->spa_claiming)) {
2630                 /*
2631                  * This is either a normal write (not a repair), or it's
2632                  * a repair induced by the scrub thread, or it's a repair
2633                  * made by zil_claim() during spa_load() in the first txg.
2634                  * In the normal case, we commit the DTL change in the same
2635                  * txg as the block was born.  In the scrub-induced repair
2636                  * case, we know that scrubs run in first-pass syncing context,
2637                  * so we commit the DTL change in spa_syncing_txg(spa).
2638                  * In the zil_claim() case, we commit in spa_first_txg(spa).
2639                  *
2640                  * We currently do not make DTL entries for failed spontaneous
2641                  * self-healing writes triggered by normal (non-scrubbing)
2642                  * reads, because we have no transactional context in which to
2643                  * do so -- and it's not clear that it'd be desirable anyway.
2644                  */
2645                 if (vd->vdev_ops->vdev_op_leaf) {
2646                         uint64_t commit_txg = txg;
2647                         if (flags & ZIO_FLAG_SCAN_THREAD) {
2648                                 ASSERT(flags & ZIO_FLAG_IO_REPAIR);
2649                                 ASSERT(spa_sync_pass(spa) == 1);
2650                                 vdev_dtl_dirty(vd, DTL_SCRUB, txg, 1);
2651                                 commit_txg = spa_syncing_txg(spa);
2652                         } else if (spa->spa_claiming) {
2653                                 ASSERT(flags & ZIO_FLAG_IO_REPAIR);
2654                                 commit_txg = spa_first_txg(spa);
2655                         }
2656                         ASSERT(commit_txg >= spa_syncing_txg(spa));
2657                         if (vdev_dtl_contains(vd, DTL_MISSING, txg, 1))
2658                                 return;
2659                         for (pvd = vd; pvd != rvd; pvd = pvd->vdev_parent)
2660                                 vdev_dtl_dirty(pvd, DTL_PARTIAL, txg, 1);
2661                         vdev_dirty(vd->vdev_top, VDD_DTL, vd, commit_txg);
2662                 }
2663                 if (vd != rvd)
2664                         vdev_dtl_dirty(vd, DTL_MISSING, txg, 1);
2665         }
2666 }
2667 
2668 /*
2669  * Update the in-core space usage stats for this vdev, its metaslab class,
2670  * and the root vdev.
2671  */
2672 void
2673 vdev_space_update(vdev_t *vd, int64_t alloc_delta, int64_t defer_delta,
2674     int64_t space_delta)
2675 {
2676         int64_t dspace_delta = space_delta;
2677         spa_t *spa = vd->vdev_spa;
2678         vdev_t *rvd = spa->spa_root_vdev;
2679         metaslab_group_t *mg = vd->vdev_mg;
2680         metaslab_class_t *mc = mg ? mg->mg_class : NULL;
2681 
2682         ASSERT(vd == vd->vdev_top);
2683 
2684         /*
2685          * Apply the inverse of the psize-to-asize (ie. RAID-Z) space-expansion
2686          * factor.  We must calculate this here and not at the root vdev
2687          * because the root vdev's psize-to-asize is simply the max of its
2688          * childrens', thus not accurate enough for us.
2689          */
2690         ASSERT((dspace_delta & (SPA_MINBLOCKSIZE-1)) == 0);
2691         ASSERT(vd->vdev_deflate_ratio != 0 || vd->vdev_isl2cache);
2692         dspace_delta = (dspace_delta >> SPA_MINBLOCKSHIFT) *
2693             vd->vdev_deflate_ratio;
2694 
2695         mutex_enter(&vd->vdev_stat_lock);
2696         vd->vdev_stat.vs_alloc += alloc_delta;
2697         vd->vdev_stat.vs_space += space_delta;
2698         vd->vdev_stat.vs_dspace += dspace_delta;
2699         mutex_exit(&vd->vdev_stat_lock);
2700 
2701         if (mc == spa_normal_class(spa)) {
2702                 mutex_enter(&rvd->vdev_stat_lock);
2703                 rvd->vdev_stat.vs_alloc += alloc_delta;
2704                 rvd->vdev_stat.vs_space += space_delta;
2705                 rvd->vdev_stat.vs_dspace += dspace_delta;
2706                 mutex_exit(&rvd->vdev_stat_lock);
2707         }
2708 
2709         if (mc != NULL) {
2710                 ASSERT(rvd == vd->vdev_parent);
2711                 ASSERT(vd->vdev_ms_count != 0);
2712 
2713                 metaslab_class_space_update(mc,
2714                     alloc_delta, defer_delta, space_delta, dspace_delta);
2715         }
2716 }
2717 
2718 /*
2719  * Mark a top-level vdev's config as dirty, placing it on the dirty list
2720  * so that it will be written out next time the vdev configuration is synced.
2721  * If the root vdev is specified (vdev_top == NULL), dirty all top-level vdevs.
2722  */
2723 void
2724 vdev_config_dirty(vdev_t *vd)
2725 {
2726         spa_t *spa = vd->vdev_spa;
2727         vdev_t *rvd = spa->spa_root_vdev;
2728         int c;
2729 
2730         ASSERT(spa_writeable(spa));
2731 
2732         /*
2733          * If this is an aux vdev (as with l2cache and spare devices), then we
2734          * update the vdev config manually and set the sync flag.
2735          */
2736         if (vd->vdev_aux != NULL) {
2737                 spa_aux_vdev_t *sav = vd->vdev_aux;
2738                 nvlist_t **aux;
2739                 uint_t naux;
2740 
2741                 for (c = 0; c < sav->sav_count; c++) {
2742                         if (sav->sav_vdevs[c] == vd)
2743                                 break;
2744                 }
2745 
2746                 if (c == sav->sav_count) {
2747                         /*
2748                          * We're being removed.  There's nothing more to do.
2749                          */
2750                         ASSERT(sav->sav_sync == B_TRUE);
2751                         return;
2752                 }
2753 
2754                 sav->sav_sync = B_TRUE;
2755 
2756                 if (nvlist_lookup_nvlist_array(sav->sav_config,
2757                     ZPOOL_CONFIG_L2CACHE, &aux, &naux) != 0) {
2758                         VERIFY(nvlist_lookup_nvlist_array(sav->sav_config,
2759                             ZPOOL_CONFIG_SPARES, &aux, &naux) == 0);
2760                 }
2761 
2762                 ASSERT(c < naux);
2763 
2764                 /*
2765                  * Setting the nvlist in the middle if the array is a little
2766                  * sketchy, but it will work.
2767                  */
2768                 nvlist_free(aux[c]);
2769                 aux[c] = vdev_config_generate(spa, vd, B_TRUE, 0);
2770 
2771                 return;
2772         }
2773 
2774         /*
2775          * The dirty list is protected by the SCL_CONFIG lock.  The caller
2776          * must either hold SCL_CONFIG as writer, or must be the sync thread
2777          * (which holds SCL_CONFIG as reader).  There's only one sync thread,
2778          * so this is sufficient to ensure mutual exclusion.
2779          */
2780         ASSERT(spa_config_held(spa, SCL_CONFIG, RW_WRITER) ||
2781             (dsl_pool_sync_context(spa_get_dsl(spa)) &&
2782             spa_config_held(spa, SCL_CONFIG, RW_READER)));
2783 
2784         if (vd == rvd) {
2785                 for (c = 0; c < rvd->vdev_children; c++)
2786                         vdev_config_dirty(rvd->vdev_child[c]);
2787         } else {
2788                 ASSERT(vd == vd->vdev_top);
2789 
2790                 if (!list_link_active(&vd->vdev_config_dirty_node) &&
2791                     !vd->vdev_ishole)
2792                         list_insert_head(&spa->spa_config_dirty_list, vd);
2793         }
2794 }
2795 
2796 void
2797 vdev_config_clean(vdev_t *vd)
2798 {
2799         spa_t *spa = vd->vdev_spa;
2800 
2801         ASSERT(spa_config_held(spa, SCL_CONFIG, RW_WRITER) ||
2802             (dsl_pool_sync_context(spa_get_dsl(spa)) &&
2803             spa_config_held(spa, SCL_CONFIG, RW_READER)));
2804 
2805         ASSERT(list_link_active(&vd->vdev_config_dirty_node));
2806         list_remove(&spa->spa_config_dirty_list, vd);
2807 }
2808 
2809 /*
2810  * Mark a top-level vdev's state as dirty, so that the next pass of
2811  * spa_sync() can convert this into vdev_config_dirty().  We distinguish
2812  * the state changes from larger config changes because they require
2813  * much less locking, and are often needed for administrative actions.
2814  */
2815 void
2816 vdev_state_dirty(vdev_t *vd)
2817 {
2818         spa_t *spa = vd->vdev_spa;
2819 
2820         ASSERT(spa_writeable(spa));
2821         ASSERT(vd == vd->vdev_top);
2822 
2823         /*
2824          * The state list is protected by the SCL_STATE lock.  The caller
2825          * must either hold SCL_STATE as writer, or must be the sync thread
2826          * (which holds SCL_STATE as reader).  There's only one sync thread,
2827          * so this is sufficient to ensure mutual exclusion.
2828          */
2829         ASSERT(spa_config_held(spa, SCL_STATE, RW_WRITER) ||
2830             (dsl_pool_sync_context(spa_get_dsl(spa)) &&
2831             spa_config_held(spa, SCL_STATE, RW_READER)));
2832 
2833         if (!list_link_active(&vd->vdev_state_dirty_node) && !vd->vdev_ishole)
2834                 list_insert_head(&spa->spa_state_dirty_list, vd);
2835 }
2836 
2837 void
2838 vdev_state_clean(vdev_t *vd)
2839 {
2840         spa_t *spa = vd->vdev_spa;
2841 
2842         ASSERT(spa_config_held(spa, SCL_STATE, RW_WRITER) ||
2843             (dsl_pool_sync_context(spa_get_dsl(spa)) &&
2844             spa_config_held(spa, SCL_STATE, RW_READER)));
2845 
2846         ASSERT(list_link_active(&vd->vdev_state_dirty_node));
2847         list_remove(&spa->spa_state_dirty_list, vd);
2848 }
2849 
2850 /*
2851  * Propagate vdev state up from children to parent.
2852  */
2853 void
2854 vdev_propagate_state(vdev_t *vd)
2855 {
2856         spa_t *spa = vd->vdev_spa;
2857         vdev_t *rvd = spa->spa_root_vdev;
2858         int degraded = 0, faulted = 0;
2859         int corrupted = 0;
2860         vdev_t *child;
2861 
2862         if (vd->vdev_children > 0) {
2863                 for (int c = 0; c < vd->vdev_children; c++) {
2864                         child = vd->vdev_child[c];
2865 
2866                         /*
2867                          * Don't factor holes into the decision.
2868                          */
2869                         if (child->vdev_ishole)
2870                                 continue;
2871 
2872                         if (!vdev_readable(child) ||
2873                             (!vdev_writeable(child) && spa_writeable(spa))) {
2874                                 /*
2875                                  * Root special: if there is a top-level log
2876                                  * device, treat the root vdev as if it were
2877                                  * degraded.
2878                                  */
2879                                 if (child->vdev_islog && vd == rvd)
2880                                         degraded++;
2881                                 else
2882                                         faulted++;
2883                         } else if (child->vdev_state <= VDEV_STATE_DEGRADED) {
2884                                 degraded++;
2885                         }
2886 
2887                         if (child->vdev_stat.vs_aux == VDEV_AUX_CORRUPT_DATA)
2888                                 corrupted++;
2889                 }
2890 
2891                 vd->vdev_ops->vdev_op_state_change(vd, faulted, degraded);
2892 
2893                 /*
2894                  * Root special: if there is a top-level vdev that cannot be
2895                  * opened due to corrupted metadata, then propagate the root
2896                  * vdev's aux state as 'corrupt' rather than 'insufficient
2897                  * replicas'.
2898                  */
2899                 if (corrupted && vd == rvd &&
2900                     rvd->vdev_state == VDEV_STATE_CANT_OPEN)
2901                         vdev_set_state(rvd, B_FALSE, VDEV_STATE_CANT_OPEN,
2902                             VDEV_AUX_CORRUPT_DATA);
2903         }
2904 
2905         if (vd->vdev_parent)
2906                 vdev_propagate_state(vd->vdev_parent);
2907 }
2908 
2909 /*
2910  * Set a vdev's state.  If this is during an open, we don't update the parent
2911  * state, because we're in the process of opening children depth-first.
2912  * Otherwise, we propagate the change to the parent.
2913  *
2914  * If this routine places a device in a faulted state, an appropriate ereport is
2915  * generated.
2916  */
2917 void
2918 vdev_set_state(vdev_t *vd, boolean_t isopen, vdev_state_t state, vdev_aux_t aux)
2919 {
2920         uint64_t save_state;
2921         spa_t *spa = vd->vdev_spa;
2922 
2923         if (state == vd->vdev_state) {
2924                 vd->vdev_stat.vs_aux = aux;
2925                 return;
2926         }
2927 
2928         save_state = vd->vdev_state;
2929 
2930         vd->vdev_state = state;
2931         vd->vdev_stat.vs_aux = aux;
2932 
2933         /*
2934          * If we are setting the vdev state to anything but an open state, then
2935          * always close the underlying device unless the device has requested
2936          * a delayed close (i.e. we're about to remove or fault the device).
2937          * Otherwise, we keep accessible but invalid devices open forever.
2938          * We don't call vdev_close() itself, because that implies some extra
2939          * checks (offline, etc) that we don't want here.  This is limited to
2940          * leaf devices, because otherwise closing the device will affect other
2941          * children.
2942          */
2943         if (!vd->vdev_delayed_close && vdev_is_dead(vd) &&
2944             vd->vdev_ops->vdev_op_leaf)
2945                 vd->vdev_ops->vdev_op_close(vd);
2946 
2947         /*
2948          * If we have brought this vdev back into service, we need
2949          * to notify fmd so that it can gracefully repair any outstanding
2950          * cases due to a missing device.  We do this in all cases, even those
2951          * that probably don't correlate to a repaired fault.  This is sure to
2952          * catch all cases, and we let the zfs-retire agent sort it out.  If
2953          * this is a transient state it's OK, as the retire agent will
2954          * double-check the state of the vdev before repairing it.
2955          */
2956         if (state == VDEV_STATE_HEALTHY && vd->vdev_ops->vdev_op_leaf &&
2957             vd->vdev_prevstate != state)
2958                 zfs_post_state_change(spa, vd);
2959 
2960         if (vd->vdev_removed &&
2961             state == VDEV_STATE_CANT_OPEN &&
2962             (aux == VDEV_AUX_OPEN_FAILED || vd->vdev_checkremove)) {
2963                 /*
2964                  * If the previous state is set to VDEV_STATE_REMOVED, then this
2965                  * device was previously marked removed and someone attempted to
2966                  * reopen it.  If this failed due to a nonexistent device, then
2967                  * keep the device in the REMOVED state.  We also let this be if
2968                  * it is one of our special test online cases, which is only
2969                  * attempting to online the device and shouldn't generate an FMA
2970                  * fault.
2971                  */
2972                 vd->vdev_state = VDEV_STATE_REMOVED;
2973                 vd->vdev_stat.vs_aux = VDEV_AUX_NONE;
2974         } else if (state == VDEV_STATE_REMOVED) {
2975                 vd->vdev_removed = B_TRUE;
2976         } else if (state == VDEV_STATE_CANT_OPEN) {
2977                 /*
2978                  * If we fail to open a vdev during an import or recovery, we
2979                  * mark it as "not available", which signifies that it was
2980                  * never there to begin with.  Failure to open such a device
2981                  * is not considered an error.
2982                  */
2983                 if ((spa_load_state(spa) == SPA_LOAD_IMPORT ||
2984                     spa_load_state(spa) == SPA_LOAD_RECOVER) &&
2985                     vd->vdev_ops->vdev_op_leaf)
2986                         vd->vdev_not_present = 1;
2987 
2988                 /*
2989                  * Post the appropriate ereport.  If the 'prevstate' field is
2990                  * set to something other than VDEV_STATE_UNKNOWN, it indicates
2991                  * that this is part of a vdev_reopen().  In this case, we don't
2992                  * want to post the ereport if the device was already in the
2993                  * CANT_OPEN state beforehand.
2994                  *
2995                  * If the 'checkremove' flag is set, then this is an attempt to
2996                  * online the device in response to an insertion event.  If we
2997                  * hit this case, then we have detected an insertion event for a
2998                  * faulted or offline device that wasn't in the removed state.
2999                  * In this scenario, we don't post an ereport because we are
3000                  * about to replace the device, or attempt an online with
3001                  * vdev_forcefault, which will generate the fault for us.
3002                  */
3003                 if ((vd->vdev_prevstate != state || vd->vdev_forcefault) &&
3004                     !vd->vdev_not_present && !vd->vdev_checkremove &&
3005                     vd != spa->spa_root_vdev) {
3006                         const char *class;
3007 
3008                         switch (aux) {
3009                         case VDEV_AUX_OPEN_FAILED:
3010                                 class = FM_EREPORT_ZFS_DEVICE_OPEN_FAILED;
3011                                 break;
3012                         case VDEV_AUX_CORRUPT_DATA:
3013                                 class = FM_EREPORT_ZFS_DEVICE_CORRUPT_DATA;
3014                                 break;
3015                         case VDEV_AUX_NO_REPLICAS:
3016                                 class = FM_EREPORT_ZFS_DEVICE_NO_REPLICAS;
3017                                 break;
3018                         case VDEV_AUX_BAD_GUID_SUM:
3019                                 class = FM_EREPORT_ZFS_DEVICE_BAD_GUID_SUM;
3020                                 break;
3021                         case VDEV_AUX_TOO_SMALL:
3022                                 class = FM_EREPORT_ZFS_DEVICE_TOO_SMALL;
3023                                 break;
3024                         case VDEV_AUX_BAD_LABEL:
3025                                 class = FM_EREPORT_ZFS_DEVICE_BAD_LABEL;
3026                                 break;
3027                         default:
3028                                 class = FM_EREPORT_ZFS_DEVICE_UNKNOWN;
3029                         }
3030 
3031                         zfs_ereport_post(class, spa, vd, NULL, save_state, 0);
3032                 }
3033 
3034                 /* Erase any notion of persistent removed state */
3035                 vd->vdev_removed = B_FALSE;
3036         } else {
3037                 vd->vdev_removed = B_FALSE;
3038         }
3039 
3040         if (!isopen && vd->vdev_parent)
3041                 vdev_propagate_state(vd->vdev_parent);
3042 }
3043 
3044 /*
3045  * Check the vdev configuration to ensure that it's capable of supporting
3046  * a root pool. Currently, we do not support RAID-Z or partial configuration.
3047  * In addition, only a single top-level vdev is allowed and none of the leaves
3048  * can be wholedisks.
3049  */
3050 boolean_t
3051 vdev_is_bootable(vdev_t *vd)
3052 {
3053         if (!vd->vdev_ops->vdev_op_leaf) {
3054                 char *vdev_type = vd->vdev_ops->vdev_op_type;
3055 
3056                 if (strcmp(vdev_type, VDEV_TYPE_ROOT) == 0 &&
3057                     vd->vdev_children > 1) {
3058                         return (B_FALSE);
3059                 } else if (strcmp(vdev_type, VDEV_TYPE_RAIDZ) == 0 ||
3060                     strcmp(vdev_type, VDEV_TYPE_MISSING) == 0) {
3061                         return (B_FALSE);
3062                 }
3063         } else if (vd->vdev_wholedisk == 1) {
3064                 return (B_FALSE);
3065         }
3066 
3067         for (int c = 0; c < vd->vdev_children; c++) {
3068                 if (!vdev_is_bootable(vd->vdev_child[c]))
3069                         return (B_FALSE);
3070         }
3071         return (B_TRUE);
3072 }
3073 
3074 /*
3075  * Load the state from the original vdev tree (ovd) which
3076  * we've retrieved from the MOS config object. If the original
3077  * vdev was offline or faulted then we transfer that state to the
3078  * device in the current vdev tree (nvd).
3079  */
3080 void
3081 vdev_load_log_state(vdev_t *nvd, vdev_t *ovd)
3082 {
3083         spa_t *spa = nvd->vdev_spa;
3084 
3085         ASSERT(nvd->vdev_top->vdev_islog);
3086         ASSERT(spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
3087         ASSERT3U(nvd->vdev_guid, ==, ovd->vdev_guid);
3088 
3089         for (int c = 0; c < nvd->vdev_children; c++)
3090                 vdev_load_log_state(nvd->vdev_child[c], ovd->vdev_child[c]);
3091 
3092         if (nvd->vdev_ops->vdev_op_leaf) {
3093                 /*
3094                  * Restore the persistent vdev state
3095                  */
3096                 nvd->vdev_offline = ovd->vdev_offline;
3097                 nvd->vdev_faulted = ovd->vdev_faulted;
3098                 nvd->vdev_degraded = ovd->vdev_degraded;
3099                 nvd->vdev_removed = ovd->vdev_removed;
3100         }
3101 }
3102 
3103 /*
3104  * Determine if a log device has valid content.  If the vdev was
3105  * removed or faulted in the MOS config then we know that
3106  * the content on the log device has already been written to the pool.
3107  */
3108 boolean_t
3109 vdev_log_state_valid(vdev_t *vd)
3110 {
3111         if (vd->vdev_ops->vdev_op_leaf && !vd->vdev_faulted &&
3112             !vd->vdev_removed)
3113                 return (B_TRUE);
3114 
3115         for (int c = 0; c < vd->vdev_children; c++)
3116                 if (vdev_log_state_valid(vd->vdev_child[c]))
3117                         return (B_TRUE);
3118 
3119         return (B_FALSE);
3120 }
3121 
3122 /*
3123  * Expand a vdev if possible.
3124  */
3125 void
3126 vdev_expand(vdev_t *vd, uint64_t txg)
3127 {
3128         ASSERT(vd->vdev_top == vd);
3129         ASSERT(spa_config_held(vd->vdev_spa, SCL_ALL, RW_WRITER) == SCL_ALL);
3130 
3131         if ((vd->vdev_asize >> vd->vdev_ms_shift) > vd->vdev_ms_count) {
3132                 VERIFY(vdev_metaslab_init(vd, txg) == 0);
3133                 vdev_config_dirty(vd);
3134         }
3135 }
3136 
3137 /*
3138  * Split a vdev.
3139  */
3140 void
3141 vdev_split(vdev_t *vd)
3142 {
3143         vdev_t *cvd, *pvd = vd->vdev_parent;
3144 
3145         vdev_remove_child(pvd, vd);
3146         vdev_compact_children(pvd);
3147 
3148         cvd = pvd->vdev_child[0];
3149         if (pvd->vdev_children == 1) {
3150                 vdev_remove_parent(cvd);
3151                 cvd->vdev_splitting = B_TRUE;
3152         }
3153         vdev_propagate_state(cvd);
3154 }