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) 2011, 2014 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/space_reftree.h>
  40 #include <sys/zio.h>
  41 #include <sys/zap.h>
  42 #include <sys/fs/zfs.h>
  43 #include <sys/arc.h>
  44 #include <sys/zil.h>
  45 #include <sys/dsl_scan.h>
  46 
  47 /*
  48  * Virtual device management.
  49  */
  50 
  51 static vdev_ops_t *vdev_ops_table[] = {
  52         &vdev_root_ops,
  53         &vdev_raidz_ops,
  54         &vdev_mirror_ops,
  55         &vdev_replacing_ops,
  56         &vdev_spare_ops,
  57         &vdev_disk_ops,
  58         &vdev_file_ops,
  59         &vdev_missing_ops,
  60         &vdev_hole_ops,
  61         NULL
  62 };
  63 
  64 /* maximum scrub/resilver I/O queue per leaf vdev */
  65 int zfs_scrub_limit = 10;
  66 
  67 /*
  68  * Given a vdev type, return the appropriate ops vector.
  69  */
  70 static vdev_ops_t *
  71 vdev_getops(const char *type)
  72 {
  73         vdev_ops_t *ops, **opspp;
  74 
  75         for (opspp = vdev_ops_table; (ops = *opspp) != NULL; opspp++)
  76                 if (strcmp(ops->vdev_op_type, type) == 0)
  77                         break;
  78 
  79         return (ops);
  80 }
  81 
  82 /*
  83  * Default asize function: return the MAX of psize with the asize of
  84  * all children.  This is what's used by anything other than RAID-Z.
  85  */
  86 uint64_t
  87 vdev_default_asize(vdev_t *vd, uint64_t psize)
  88 {
  89         uint64_t asize = P2ROUNDUP(psize, 1ULL << vd->vdev_top->vdev_ashift);
  90         uint64_t csize;
  91 
  92         for (int c = 0; c < vd->vdev_children; c++) {
  93                 csize = vdev_psize_to_asize(vd->vdev_child[c], psize);
  94                 asize = MAX(asize, csize);
  95         }
  96 
  97         return (asize);
  98 }
  99 
 100 /*
 101  * Get the minimum allocatable size. We define the allocatable size as
 102  * the vdev's asize rounded to the nearest metaslab. This allows us to
 103  * replace or attach devices which don't have the same physical size but
 104  * can still satisfy the same number of allocations.
 105  */
 106 uint64_t
 107 vdev_get_min_asize(vdev_t *vd)
 108 {
 109         vdev_t *pvd = vd->vdev_parent;
 110 
 111         /*
 112          * If our parent is NULL (inactive spare or cache) or is the root,
 113          * just return our own asize.
 114          */
 115         if (pvd == NULL)
 116                 return (vd->vdev_asize);
 117 
 118         /*
 119          * The top-level vdev just returns the allocatable size rounded
 120          * to the nearest metaslab.
 121          */
 122         if (vd == vd->vdev_top)
 123                 return (P2ALIGN(vd->vdev_asize, 1ULL << vd->vdev_ms_shift));
 124 
 125         /*
 126          * The allocatable space for a raidz vdev is N * sizeof(smallest child),
 127          * so each child must provide at least 1/Nth of its asize.
 128          */
 129         if (pvd->vdev_ops == &vdev_raidz_ops)
 130                 return (pvd->vdev_min_asize / pvd->vdev_children);
 131 
 132         return (pvd->vdev_min_asize);
 133 }
 134 
 135 void
 136 vdev_set_min_asize(vdev_t *vd)
 137 {
 138         vd->vdev_min_asize = vdev_get_min_asize(vd);
 139 
 140         for (int c = 0; c < vd->vdev_children; c++)
 141                 vdev_set_min_asize(vd->vdev_child[c]);
 142 }
 143 
 144 vdev_t *
 145 vdev_lookup_top(spa_t *spa, uint64_t vdev)
 146 {
 147         vdev_t *rvd = spa->spa_root_vdev;
 148 
 149         ASSERT(spa_config_held(spa, SCL_ALL, RW_READER) != 0);
 150 
 151         if (vdev < rvd->vdev_children) {
 152                 ASSERT(rvd->vdev_child[vdev] != NULL);
 153                 return (rvd->vdev_child[vdev]);
 154         }
 155 
 156         return (NULL);
 157 }
 158 
 159 vdev_t *
 160 vdev_lookup_by_guid(vdev_t *vd, uint64_t guid)
 161 {
 162         vdev_t *mvd;
 163 
 164         if (vd->vdev_guid == guid)
 165                 return (vd);
 166 
 167         for (int c = 0; c < vd->vdev_children; c++)
 168                 if ((mvd = vdev_lookup_by_guid(vd->vdev_child[c], guid)) !=
 169                     NULL)
 170                         return (mvd);
 171 
 172         return (NULL);
 173 }
 174 
 175 void
 176 vdev_add_child(vdev_t *pvd, vdev_t *cvd)
 177 {
 178         size_t oldsize, newsize;
 179         uint64_t id = cvd->vdev_id;
 180         vdev_t **newchild;
 181 
 182         ASSERT(spa_config_held(cvd->vdev_spa, SCL_ALL, RW_WRITER) == SCL_ALL);
 183         ASSERT(cvd->vdev_parent == NULL);
 184 
 185         cvd->vdev_parent = pvd;
 186 
 187         if (pvd == NULL)
 188                 return;
 189 
 190         ASSERT(id >= pvd->vdev_children || pvd->vdev_child[id] == NULL);
 191 
 192         oldsize = pvd->vdev_children * sizeof (vdev_t *);
 193         pvd->vdev_children = MAX(pvd->vdev_children, id + 1);
 194         newsize = pvd->vdev_children * sizeof (vdev_t *);
 195 
 196         newchild = kmem_zalloc(newsize, KM_SLEEP);
 197         if (pvd->vdev_child != NULL) {
 198                 bcopy(pvd->vdev_child, newchild, oldsize);
 199                 kmem_free(pvd->vdev_child, oldsize);
 200         }
 201 
 202         pvd->vdev_child = newchild;
 203         pvd->vdev_child[id] = cvd;
 204 
 205         cvd->vdev_top = (pvd->vdev_top ? pvd->vdev_top: cvd);
 206         ASSERT(cvd->vdev_top->vdev_parent->vdev_parent == NULL);
 207 
 208         /*
 209          * Walk up all ancestors to update guid sum.
 210          */
 211         for (; pvd != NULL; pvd = pvd->vdev_parent)
 212                 pvd->vdev_guid_sum += cvd->vdev_guid_sum;
 213 }
 214 
 215 void
 216 vdev_remove_child(vdev_t *pvd, vdev_t *cvd)
 217 {
 218         int c;
 219         uint_t id = cvd->vdev_id;
 220 
 221         ASSERT(cvd->vdev_parent == pvd);
 222 
 223         if (pvd == NULL)
 224                 return;
 225 
 226         ASSERT(id < pvd->vdev_children);
 227         ASSERT(pvd->vdev_child[id] == cvd);
 228 
 229         pvd->vdev_child[id] = NULL;
 230         cvd->vdev_parent = NULL;
 231 
 232         for (c = 0; c < pvd->vdev_children; c++)
 233                 if (pvd->vdev_child[c])
 234                         break;
 235 
 236         if (c == pvd->vdev_children) {
 237                 kmem_free(pvd->vdev_child, c * sizeof (vdev_t *));
 238                 pvd->vdev_child = NULL;
 239                 pvd->vdev_children = 0;
 240         }
 241 
 242         /*
 243          * Walk up all ancestors to update guid sum.
 244          */
 245         for (; pvd != NULL; pvd = pvd->vdev_parent)
 246                 pvd->vdev_guid_sum -= cvd->vdev_guid_sum;
 247 }
 248 
 249 /*
 250  * Remove any holes in the child array.
 251  */
 252 void
 253 vdev_compact_children(vdev_t *pvd)
 254 {
 255         vdev_t **newchild, *cvd;
 256         int oldc = pvd->vdev_children;
 257         int newc;
 258 
 259         ASSERT(spa_config_held(pvd->vdev_spa, SCL_ALL, RW_WRITER) == SCL_ALL);
 260 
 261         for (int c = newc = 0; c < oldc; c++)
 262                 if (pvd->vdev_child[c])
 263                         newc++;
 264 
 265         newchild = kmem_alloc(newc * sizeof (vdev_t *), KM_SLEEP);
 266 
 267         for (int c = newc = 0; c < oldc; c++) {
 268                 if ((cvd = pvd->vdev_child[c]) != NULL) {
 269                         newchild[newc] = cvd;
 270                         cvd->vdev_id = newc++;
 271                 }
 272         }
 273 
 274         kmem_free(pvd->vdev_child, oldc * sizeof (vdev_t *));
 275         pvd->vdev_child = newchild;
 276         pvd->vdev_children = newc;
 277 }
 278 
 279 /*
 280  * Allocate and minimally initialize a vdev_t.
 281  */
 282 vdev_t *
 283 vdev_alloc_common(spa_t *spa, uint_t id, uint64_t guid, vdev_ops_t *ops)
 284 {
 285         vdev_t *vd;
 286 
 287         vd = kmem_zalloc(sizeof (vdev_t), KM_SLEEP);
 288 
 289         if (spa->spa_root_vdev == NULL) {
 290                 ASSERT(ops == &vdev_root_ops);
 291                 spa->spa_root_vdev = vd;
 292                 spa->spa_load_guid = spa_generate_guid(NULL);
 293         }
 294 
 295         if (guid == 0 && ops != &vdev_hole_ops) {
 296                 if (spa->spa_root_vdev == vd) {
 297                         /*
 298                          * The root vdev's guid will also be the pool guid,
 299                          * which must be unique among all pools.
 300                          */
 301                         guid = spa_generate_guid(NULL);
 302                 } else {
 303                         /*
 304                          * Any other vdev's guid must be unique within the pool.
 305                          */
 306                         guid = spa_generate_guid(spa);
 307                 }
 308                 ASSERT(!spa_guid_exists(spa_guid(spa), guid));
 309         }
 310 
 311         vd->vdev_spa = spa;
 312         vd->vdev_id = id;
 313         vd->vdev_guid = guid;
 314         vd->vdev_guid_sum = guid;
 315         vd->vdev_ops = ops;
 316         vd->vdev_state = VDEV_STATE_CLOSED;
 317         vd->vdev_ishole = (ops == &vdev_hole_ops);
 318 
 319         mutex_init(&vd->vdev_dtl_lock, NULL, MUTEX_DEFAULT, NULL);
 320         mutex_init(&vd->vdev_stat_lock, NULL, MUTEX_DEFAULT, NULL);
 321         mutex_init(&vd->vdev_probe_lock, NULL, MUTEX_DEFAULT, NULL);
 322         for (int t = 0; t < DTL_TYPES; t++) {
 323                 vd->vdev_dtl[t] = range_tree_create(NULL, NULL,
 324                     &vd->vdev_dtl_lock);
 325         }
 326         txg_list_create(&vd->vdev_ms_list,
 327             offsetof(struct metaslab, ms_txg_node));
 328         txg_list_create(&vd->vdev_dtl_list,
 329             offsetof(struct vdev, vdev_dtl_node));
 330         vd->vdev_stat.vs_timestamp = gethrtime();
 331         vdev_queue_init(vd);
 332         vdev_cache_init(vd);
 333 
 334         return (vd);
 335 }
 336 
 337 /*
 338  * Allocate a new vdev.  The 'alloctype' is used to control whether we are
 339  * creating a new vdev or loading an existing one - the behavior is slightly
 340  * different for each case.
 341  */
 342 int
 343 vdev_alloc(spa_t *spa, vdev_t **vdp, nvlist_t *nv, vdev_t *parent, uint_t id,
 344     int alloctype)
 345 {
 346         vdev_ops_t *ops;
 347         char *type;
 348         uint64_t guid = 0, islog, nparity;
 349         vdev_t *vd;
 350 
 351         ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL);
 352 
 353         if (nvlist_lookup_string(nv, ZPOOL_CONFIG_TYPE, &type) != 0)
 354                 return (SET_ERROR(EINVAL));
 355 
 356         if ((ops = vdev_getops(type)) == NULL)
 357                 return (SET_ERROR(EINVAL));
 358 
 359         /*
 360          * If this is a load, get the vdev guid from the nvlist.
 361          * Otherwise, vdev_alloc_common() will generate one for us.
 362          */
 363         if (alloctype == VDEV_ALLOC_LOAD) {
 364                 uint64_t label_id;
 365 
 366                 if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_ID, &label_id) ||
 367                     label_id != id)
 368                         return (SET_ERROR(EINVAL));
 369 
 370                 if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_GUID, &guid) != 0)
 371                         return (SET_ERROR(EINVAL));
 372         } else if (alloctype == VDEV_ALLOC_SPARE) {
 373                 if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_GUID, &guid) != 0)
 374                         return (SET_ERROR(EINVAL));
 375         } else if (alloctype == VDEV_ALLOC_L2CACHE) {
 376                 if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_GUID, &guid) != 0)
 377                         return (SET_ERROR(EINVAL));
 378         } else if (alloctype == VDEV_ALLOC_ROOTPOOL) {
 379                 if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_GUID, &guid) != 0)
 380                         return (SET_ERROR(EINVAL));
 381         }
 382 
 383         /*
 384          * The first allocated vdev must be of type 'root'.
 385          */
 386         if (ops != &vdev_root_ops && spa->spa_root_vdev == NULL)
 387                 return (SET_ERROR(EINVAL));
 388 
 389         /*
 390          * Determine whether we're a log vdev.
 391          */
 392         islog = 0;
 393         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_IS_LOG, &islog);
 394         if (islog && spa_version(spa) < SPA_VERSION_SLOGS)
 395                 return (SET_ERROR(ENOTSUP));
 396 
 397         if (ops == &vdev_hole_ops && spa_version(spa) < SPA_VERSION_HOLES)
 398                 return (SET_ERROR(ENOTSUP));
 399 
 400         /*
 401          * Set the nparity property for RAID-Z vdevs.
 402          */
 403         nparity = -1ULL;
 404         if (ops == &vdev_raidz_ops) {
 405                 if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_NPARITY,
 406                     &nparity) == 0) {
 407                         if (nparity == 0 || nparity > VDEV_RAIDZ_MAXPARITY)
 408                                 return (SET_ERROR(EINVAL));
 409                         /*
 410                          * Previous versions could only support 1 or 2 parity
 411                          * device.
 412                          */
 413                         if (nparity > 1 &&
 414                             spa_version(spa) < SPA_VERSION_RAIDZ2)
 415                                 return (SET_ERROR(ENOTSUP));
 416                         if (nparity > 2 &&
 417                             spa_version(spa) < SPA_VERSION_RAIDZ3)
 418                                 return (SET_ERROR(ENOTSUP));
 419                 } else {
 420                         /*
 421                          * We require the parity to be specified for SPAs that
 422                          * support multiple parity levels.
 423                          */
 424                         if (spa_version(spa) >= SPA_VERSION_RAIDZ2)
 425                                 return (SET_ERROR(EINVAL));
 426                         /*
 427                          * Otherwise, we default to 1 parity device for RAID-Z.
 428                          */
 429                         nparity = 1;
 430                 }
 431         } else {
 432                 nparity = 0;
 433         }
 434         ASSERT(nparity != -1ULL);
 435 
 436         vd = vdev_alloc_common(spa, id, guid, ops);
 437 
 438         vd->vdev_islog = islog;
 439         vd->vdev_nparity = nparity;
 440 
 441         if (nvlist_lookup_string(nv, ZPOOL_CONFIG_PATH, &vd->vdev_path) == 0)
 442                 vd->vdev_path = spa_strdup(vd->vdev_path);
 443         if (nvlist_lookup_string(nv, ZPOOL_CONFIG_DEVID, &vd->vdev_devid) == 0)
 444                 vd->vdev_devid = spa_strdup(vd->vdev_devid);
 445         if (nvlist_lookup_string(nv, ZPOOL_CONFIG_PHYS_PATH,
 446             &vd->vdev_physpath) == 0)
 447                 vd->vdev_physpath = spa_strdup(vd->vdev_physpath);
 448         if (nvlist_lookup_string(nv, ZPOOL_CONFIG_FRU, &vd->vdev_fru) == 0)
 449                 vd->vdev_fru = spa_strdup(vd->vdev_fru);
 450 
 451         /*
 452          * Set the whole_disk property.  If it's not specified, leave the value
 453          * as -1.
 454          */
 455         if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_WHOLE_DISK,
 456             &vd->vdev_wholedisk) != 0)
 457                 vd->vdev_wholedisk = -1ULL;
 458 
 459         /*
 460          * Look for the 'not present' flag.  This will only be set if the device
 461          * was not present at the time of import.
 462          */
 463         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_NOT_PRESENT,
 464             &vd->vdev_not_present);
 465 
 466         /*
 467          * Get the alignment requirement.
 468          */
 469         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_ASHIFT, &vd->vdev_ashift);
 470 
 471         /*
 472          * Retrieve the vdev creation time.
 473          */
 474         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_CREATE_TXG,
 475             &vd->vdev_crtxg);
 476 
 477         /*
 478          * If we're a top-level vdev, try to load the allocation parameters.
 479          */
 480         if (parent && !parent->vdev_parent &&
 481             (alloctype == VDEV_ALLOC_LOAD || alloctype == VDEV_ALLOC_SPLIT)) {
 482                 (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_METASLAB_ARRAY,
 483                     &vd->vdev_ms_array);
 484                 (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_METASLAB_SHIFT,
 485                     &vd->vdev_ms_shift);
 486                 (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_ASIZE,
 487                     &vd->vdev_asize);
 488                 (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_REMOVING,
 489                     &vd->vdev_removing);
 490         }
 491 
 492         if (parent && !parent->vdev_parent && alloctype != VDEV_ALLOC_ATTACH) {
 493                 ASSERT(alloctype == VDEV_ALLOC_LOAD ||
 494                     alloctype == VDEV_ALLOC_ADD ||
 495                     alloctype == VDEV_ALLOC_SPLIT ||
 496                     alloctype == VDEV_ALLOC_ROOTPOOL);
 497                 vd->vdev_mg = metaslab_group_create(islog ?
 498                     spa_log_class(spa) : spa_normal_class(spa), vd);
 499         }
 500 
 501         /*
 502          * If we're a leaf vdev, try to load the DTL object and other state.
 503          */
 504         if (vd->vdev_ops->vdev_op_leaf &&
 505             (alloctype == VDEV_ALLOC_LOAD || alloctype == VDEV_ALLOC_L2CACHE ||
 506             alloctype == VDEV_ALLOC_ROOTPOOL)) {
 507                 if (alloctype == VDEV_ALLOC_LOAD) {
 508                         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_DTL,
 509                             &vd->vdev_dtl_object);
 510                         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_UNSPARE,
 511                             &vd->vdev_unspare);
 512                 }
 513 
 514                 if (alloctype == VDEV_ALLOC_ROOTPOOL) {
 515                         uint64_t spare = 0;
 516 
 517                         if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_IS_SPARE,
 518                             &spare) == 0 && spare)
 519                                 spa_spare_add(vd);
 520                 }
 521 
 522                 (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_OFFLINE,
 523                     &vd->vdev_offline);
 524 
 525                 (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_RESILVER_TXG,
 526                     &vd->vdev_resilver_txg);
 527 
 528                 /*
 529                  * When importing a pool, we want to ignore the persistent fault
 530                  * state, as the diagnosis made on another system may not be
 531                  * valid in the current context.  Local vdevs will
 532                  * remain in the faulted state.
 533                  */
 534                 if (spa_load_state(spa) == SPA_LOAD_OPEN) {
 535                         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_FAULTED,
 536                             &vd->vdev_faulted);
 537                         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_DEGRADED,
 538                             &vd->vdev_degraded);
 539                         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_REMOVED,
 540                             &vd->vdev_removed);
 541 
 542                         if (vd->vdev_faulted || vd->vdev_degraded) {
 543                                 char *aux;
 544 
 545                                 vd->vdev_label_aux =
 546                                     VDEV_AUX_ERR_EXCEEDED;
 547                                 if (nvlist_lookup_string(nv,
 548                                     ZPOOL_CONFIG_AUX_STATE, &aux) == 0 &&
 549                                     strcmp(aux, "external") == 0)
 550                                         vd->vdev_label_aux = VDEV_AUX_EXTERNAL;
 551                         }
 552                 }
 553         }
 554 
 555         /*
 556          * Add ourselves to the parent's list of children.
 557          */
 558         vdev_add_child(parent, vd);
 559 
 560         *vdp = vd;
 561 
 562         return (0);
 563 }
 564 
 565 void
 566 vdev_free(vdev_t *vd)
 567 {
 568         spa_t *spa = vd->vdev_spa;
 569 
 570         /*
 571          * vdev_free() implies closing the vdev first.  This is simpler than
 572          * trying to ensure complicated semantics for all callers.
 573          */
 574         vdev_close(vd);
 575 
 576         ASSERT(!list_link_active(&vd->vdev_config_dirty_node));
 577         ASSERT(!list_link_active(&vd->vdev_state_dirty_node));
 578 
 579         /*
 580          * Free all children.
 581          */
 582         for (int c = 0; c < vd->vdev_children; c++)
 583                 vdev_free(vd->vdev_child[c]);
 584 
 585         ASSERT(vd->vdev_child == NULL);
 586         ASSERT(vd->vdev_guid_sum == vd->vdev_guid);
 587 
 588         /*
 589          * Discard allocation state.
 590          */
 591         if (vd->vdev_mg != NULL) {
 592                 vdev_metaslab_fini(vd);
 593                 metaslab_group_destroy(vd->vdev_mg);
 594         }
 595 
 596         ASSERT0(vd->vdev_stat.vs_space);
 597         ASSERT0(vd->vdev_stat.vs_dspace);
 598         ASSERT0(vd->vdev_stat.vs_alloc);
 599 
 600         /*
 601          * Remove this vdev from its parent's child list.
 602          */
 603         vdev_remove_child(vd->vdev_parent, vd);
 604 
 605         ASSERT(vd->vdev_parent == NULL);
 606 
 607         /*
 608          * Clean up vdev structure.
 609          */
 610         vdev_queue_fini(vd);
 611         vdev_cache_fini(vd);
 612 
 613         if (vd->vdev_path)
 614                 spa_strfree(vd->vdev_path);
 615         if (vd->vdev_devid)
 616                 spa_strfree(vd->vdev_devid);
 617         if (vd->vdev_physpath)
 618                 spa_strfree(vd->vdev_physpath);
 619         if (vd->vdev_fru)
 620                 spa_strfree(vd->vdev_fru);
 621 
 622         if (vd->vdev_isspare)
 623                 spa_spare_remove(vd);
 624         if (vd->vdev_isl2cache)
 625                 spa_l2cache_remove(vd);
 626 
 627         txg_list_destroy(&vd->vdev_ms_list);
 628         txg_list_destroy(&vd->vdev_dtl_list);
 629 
 630         mutex_enter(&vd->vdev_dtl_lock);
 631         space_map_close(vd->vdev_dtl_sm);
 632         for (int t = 0; t < DTL_TYPES; t++) {
 633                 range_tree_vacate(vd->vdev_dtl[t], NULL, NULL);
 634                 range_tree_destroy(vd->vdev_dtl[t]);
 635         }
 636         mutex_exit(&vd->vdev_dtl_lock);
 637 
 638         mutex_destroy(&vd->vdev_dtl_lock);
 639         mutex_destroy(&vd->vdev_stat_lock);
 640         mutex_destroy(&vd->vdev_probe_lock);
 641 
 642         if (vd == spa->spa_root_vdev)
 643                 spa->spa_root_vdev = NULL;
 644 
 645         kmem_free(vd, sizeof (vdev_t));
 646 }
 647 
 648 /*
 649  * Transfer top-level vdev state from svd to tvd.
 650  */
 651 static void
 652 vdev_top_transfer(vdev_t *svd, vdev_t *tvd)
 653 {
 654         spa_t *spa = svd->vdev_spa;
 655         metaslab_t *msp;
 656         vdev_t *vd;
 657         int t;
 658 
 659         ASSERT(tvd == tvd->vdev_top);
 660 
 661         tvd->vdev_ms_array = svd->vdev_ms_array;
 662         tvd->vdev_ms_shift = svd->vdev_ms_shift;
 663         tvd->vdev_ms_count = svd->vdev_ms_count;
 664 
 665         svd->vdev_ms_array = 0;
 666         svd->vdev_ms_shift = 0;
 667         svd->vdev_ms_count = 0;
 668 
 669         if (tvd->vdev_mg)
 670                 ASSERT3P(tvd->vdev_mg, ==, svd->vdev_mg);
 671         tvd->vdev_mg = svd->vdev_mg;
 672         tvd->vdev_ms = svd->vdev_ms;
 673 
 674         svd->vdev_mg = NULL;
 675         svd->vdev_ms = NULL;
 676 
 677         if (tvd->vdev_mg != NULL)
 678                 tvd->vdev_mg->mg_vd = tvd;
 679 
 680         tvd->vdev_stat.vs_alloc = svd->vdev_stat.vs_alloc;
 681         tvd->vdev_stat.vs_space = svd->vdev_stat.vs_space;
 682         tvd->vdev_stat.vs_dspace = svd->vdev_stat.vs_dspace;
 683 
 684         svd->vdev_stat.vs_alloc = 0;
 685         svd->vdev_stat.vs_space = 0;
 686         svd->vdev_stat.vs_dspace = 0;
 687 
 688         for (t = 0; t < TXG_SIZE; t++) {
 689                 while ((msp = txg_list_remove(&svd->vdev_ms_list, t)) != NULL)
 690                         (void) txg_list_add(&tvd->vdev_ms_list, msp, t);
 691                 while ((vd = txg_list_remove(&svd->vdev_dtl_list, t)) != NULL)
 692                         (void) txg_list_add(&tvd->vdev_dtl_list, vd, t);
 693                 if (txg_list_remove_this(&spa->spa_vdev_txg_list, svd, t))
 694                         (void) txg_list_add(&spa->spa_vdev_txg_list, tvd, t);
 695         }
 696 
 697         if (list_link_active(&svd->vdev_config_dirty_node)) {
 698                 vdev_config_clean(svd);
 699                 vdev_config_dirty(tvd);
 700         }
 701 
 702         if (list_link_active(&svd->vdev_state_dirty_node)) {
 703                 vdev_state_clean(svd);
 704                 vdev_state_dirty(tvd);
 705         }
 706 
 707         tvd->vdev_deflate_ratio = svd->vdev_deflate_ratio;
 708         svd->vdev_deflate_ratio = 0;
 709 
 710         tvd->vdev_islog = svd->vdev_islog;
 711         svd->vdev_islog = 0;
 712 }
 713 
 714 static void
 715 vdev_top_update(vdev_t *tvd, vdev_t *vd)
 716 {
 717         if (vd == NULL)
 718                 return;
 719 
 720         vd->vdev_top = tvd;
 721 
 722         for (int c = 0; c < vd->vdev_children; c++)
 723                 vdev_top_update(tvd, vd->vdev_child[c]);
 724 }
 725 
 726 /*
 727  * Add a mirror/replacing vdev above an existing vdev.
 728  */
 729 vdev_t *
 730 vdev_add_parent(vdev_t *cvd, vdev_ops_t *ops)
 731 {
 732         spa_t *spa = cvd->vdev_spa;
 733         vdev_t *pvd = cvd->vdev_parent;
 734         vdev_t *mvd;
 735 
 736         ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL);
 737 
 738         mvd = vdev_alloc_common(spa, cvd->vdev_id, 0, ops);
 739 
 740         mvd->vdev_asize = cvd->vdev_asize;
 741         mvd->vdev_min_asize = cvd->vdev_min_asize;
 742         mvd->vdev_max_asize = cvd->vdev_max_asize;
 743         mvd->vdev_ashift = cvd->vdev_ashift;
 744         mvd->vdev_state = cvd->vdev_state;
 745         mvd->vdev_crtxg = cvd->vdev_crtxg;
 746 
 747         vdev_remove_child(pvd, cvd);
 748         vdev_add_child(pvd, mvd);
 749         cvd->vdev_id = mvd->vdev_children;
 750         vdev_add_child(mvd, cvd);
 751         vdev_top_update(cvd->vdev_top, cvd->vdev_top);
 752 
 753         if (mvd == mvd->vdev_top)
 754                 vdev_top_transfer(cvd, mvd);
 755 
 756         return (mvd);
 757 }
 758 
 759 /*
 760  * Remove a 1-way mirror/replacing vdev from the tree.
 761  */
 762 void
 763 vdev_remove_parent(vdev_t *cvd)
 764 {
 765         vdev_t *mvd = cvd->vdev_parent;
 766         vdev_t *pvd = mvd->vdev_parent;
 767 
 768         ASSERT(spa_config_held(cvd->vdev_spa, SCL_ALL, RW_WRITER) == SCL_ALL);
 769 
 770         ASSERT(mvd->vdev_children == 1);
 771         ASSERT(mvd->vdev_ops == &vdev_mirror_ops ||
 772             mvd->vdev_ops == &vdev_replacing_ops ||
 773             mvd->vdev_ops == &vdev_spare_ops);
 774         cvd->vdev_ashift = mvd->vdev_ashift;
 775 
 776         vdev_remove_child(mvd, cvd);
 777         vdev_remove_child(pvd, mvd);
 778 
 779         /*
 780          * If cvd will replace mvd as a top-level vdev, preserve mvd's guid.
 781          * Otherwise, we could have detached an offline device, and when we
 782          * go to import the pool we'll think we have two top-level vdevs,
 783          * instead of a different version of the same top-level vdev.
 784          */
 785         if (mvd->vdev_top == mvd) {
 786                 uint64_t guid_delta = mvd->vdev_guid - cvd->vdev_guid;
 787                 cvd->vdev_orig_guid = cvd->vdev_guid;
 788                 cvd->vdev_guid += guid_delta;
 789                 cvd->vdev_guid_sum += guid_delta;
 790 
 791                 /*
 792                  * If pool not set for autoexpand, we need to also preserve
 793                  * mvd's asize to prevent automatic expansion of cvd.
 794                  * Otherwise if we are adjusting the mirror by attaching and
 795                  * detaching children of non-uniform sizes, the mirror could
 796                  * autoexpand, unexpectedly requiring larger devices to
 797                  * re-establish the mirror.
 798                  */
 799                 if (!cvd->vdev_spa->spa_autoexpand)
 800                         cvd->vdev_asize = mvd->vdev_asize;
 801         }
 802         cvd->vdev_id = mvd->vdev_id;
 803         vdev_add_child(pvd, cvd);
 804         vdev_top_update(cvd->vdev_top, cvd->vdev_top);
 805 
 806         if (cvd == cvd->vdev_top)
 807                 vdev_top_transfer(mvd, cvd);
 808 
 809         ASSERT(mvd->vdev_children == 0);
 810         vdev_free(mvd);
 811 }
 812 
 813 int
 814 vdev_metaslab_init(vdev_t *vd, uint64_t txg)
 815 {
 816         spa_t *spa = vd->vdev_spa;
 817         objset_t *mos = spa->spa_meta_objset;
 818         uint64_t m;
 819         uint64_t oldc = vd->vdev_ms_count;
 820         uint64_t newc = vd->vdev_asize >> vd->vdev_ms_shift;
 821         metaslab_t **mspp;
 822         int error;
 823 
 824         ASSERT(txg == 0 || spa_config_held(spa, SCL_ALLOC, RW_WRITER));
 825 
 826         /*
 827          * This vdev is not being allocated from yet or is a hole.
 828          */
 829         if (vd->vdev_ms_shift == 0)
 830                 return (0);
 831 
 832         ASSERT(!vd->vdev_ishole);
 833 
 834         /*
 835          * Compute the raidz-deflation ratio.  Note, we hard-code
 836          * in 128k (1 << 17) because it is the current "typical" blocksize.
 837          * Even if SPA_MAXBLOCKSIZE changes, this algorithm must never change,
 838          * or we will inconsistently account for existing bp's.
 839          */
 840         vd->vdev_deflate_ratio = (1 << 17) /
 841             (vdev_psize_to_asize(vd, 1 << 17) >> SPA_MINBLOCKSHIFT);
 842 
 843         ASSERT(oldc <= newc);
 844 
 845         mspp = kmem_zalloc(newc * sizeof (*mspp), KM_SLEEP);
 846 
 847         if (oldc != 0) {
 848                 bcopy(vd->vdev_ms, mspp, oldc * sizeof (*mspp));
 849                 kmem_free(vd->vdev_ms, oldc * sizeof (*mspp));
 850         }
 851 
 852         vd->vdev_ms = mspp;
 853         vd->vdev_ms_count = newc;
 854 
 855         for (m = oldc; m < newc; m++) {
 856                 uint64_t object = 0;
 857 
 858                 if (txg == 0) {
 859                         error = dmu_read(mos, vd->vdev_ms_array,
 860                             m * sizeof (uint64_t), sizeof (uint64_t), &object,
 861                             DMU_READ_PREFETCH);
 862                         if (error)
 863                                 return (error);
 864                 }
 865                 vd->vdev_ms[m] = metaslab_init(vd->vdev_mg, m, object, txg);
 866         }
 867 
 868         if (txg == 0)
 869                 spa_config_enter(spa, SCL_ALLOC, FTAG, RW_WRITER);
 870 
 871         /*
 872          * If the vdev is being removed we don't activate
 873          * the metaslabs since we want to ensure that no new
 874          * allocations are performed on this device.
 875          */
 876         if (oldc == 0 && !vd->vdev_removing)
 877                 metaslab_group_activate(vd->vdev_mg);
 878 
 879         if (txg == 0)
 880                 spa_config_exit(spa, SCL_ALLOC, FTAG);
 881 
 882         return (0);
 883 }
 884 
 885 void
 886 vdev_metaslab_fini(vdev_t *vd)
 887 {
 888         uint64_t m;
 889         uint64_t count = vd->vdev_ms_count;
 890 
 891         if (vd->vdev_ms != NULL) {
 892                 metaslab_group_passivate(vd->vdev_mg);
 893                 for (m = 0; m < count; m++) {
 894                         metaslab_t *msp = vd->vdev_ms[m];
 895 
 896                         if (msp != NULL)
 897                                 metaslab_fini(msp);
 898                 }
 899                 kmem_free(vd->vdev_ms, count * sizeof (metaslab_t *));
 900                 vd->vdev_ms = NULL;
 901         }
 902 }
 903 
 904 typedef struct vdev_probe_stats {
 905         boolean_t       vps_readable;
 906         boolean_t       vps_writeable;
 907         int             vps_flags;
 908 } vdev_probe_stats_t;
 909 
 910 static void
 911 vdev_probe_done(zio_t *zio)
 912 {
 913         spa_t *spa = zio->io_spa;
 914         vdev_t *vd = zio->io_vd;
 915         vdev_probe_stats_t *vps = zio->io_private;
 916 
 917         ASSERT(vd->vdev_probe_zio != NULL);
 918 
 919         if (zio->io_type == ZIO_TYPE_READ) {
 920                 if (zio->io_error == 0)
 921                         vps->vps_readable = 1;
 922                 if (zio->io_error == 0 && spa_writeable(spa)) {
 923                         zio_nowait(zio_write_phys(vd->vdev_probe_zio, vd,
 924                             zio->io_offset, zio->io_size, zio->io_data,
 925                             ZIO_CHECKSUM_OFF, vdev_probe_done, vps,
 926                             ZIO_PRIORITY_SYNC_WRITE, vps->vps_flags, B_TRUE));
 927                 } else {
 928                         zio_buf_free(zio->io_data, zio->io_size);
 929                 }
 930         } else if (zio->io_type == ZIO_TYPE_WRITE) {
 931                 if (zio->io_error == 0)
 932                         vps->vps_writeable = 1;
 933                 zio_buf_free(zio->io_data, zio->io_size);
 934         } else if (zio->io_type == ZIO_TYPE_NULL) {
 935                 zio_t *pio;
 936 
 937                 vd->vdev_cant_read |= !vps->vps_readable;
 938                 vd->vdev_cant_write |= !vps->vps_writeable;
 939 
 940                 if (vdev_readable(vd) &&
 941                     (vdev_writeable(vd) || !spa_writeable(spa))) {
 942                         zio->io_error = 0;
 943                 } else {
 944                         ASSERT(zio->io_error != 0);
 945                         zfs_ereport_post(FM_EREPORT_ZFS_PROBE_FAILURE,
 946                             spa, vd, NULL, 0, 0);
 947                         zio->io_error = SET_ERROR(ENXIO);
 948                 }
 949 
 950                 mutex_enter(&vd->vdev_probe_lock);
 951                 ASSERT(vd->vdev_probe_zio == zio);
 952                 vd->vdev_probe_zio = NULL;
 953                 mutex_exit(&vd->vdev_probe_lock);
 954 
 955                 while ((pio = zio_walk_parents(zio)) != NULL)
 956                         if (!vdev_accessible(vd, pio))
 957                                 pio->io_error = SET_ERROR(ENXIO);
 958 
 959                 kmem_free(vps, sizeof (*vps));
 960         }
 961 }
 962 
 963 /*
 964  * Determine whether this device is accessible.
 965  *
 966  * Read and write to several known locations: the pad regions of each
 967  * vdev label but the first, which we leave alone in case it contains
 968  * a VTOC.
 969  */
 970 zio_t *
 971 vdev_probe(vdev_t *vd, zio_t *zio)
 972 {
 973         spa_t *spa = vd->vdev_spa;
 974         vdev_probe_stats_t *vps = NULL;
 975         zio_t *pio;
 976 
 977         ASSERT(vd->vdev_ops->vdev_op_leaf);
 978 
 979         /*
 980          * Don't probe the probe.
 981          */
 982         if (zio && (zio->io_flags & ZIO_FLAG_PROBE))
 983                 return (NULL);
 984 
 985         /*
 986          * To prevent 'probe storms' when a device fails, we create
 987          * just one probe i/o at a time.  All zios that want to probe
 988          * this vdev will become parents of the probe io.
 989          */
 990         mutex_enter(&vd->vdev_probe_lock);
 991 
 992         if ((pio = vd->vdev_probe_zio) == NULL) {
 993                 vps = kmem_zalloc(sizeof (*vps), KM_SLEEP);
 994 
 995                 vps->vps_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_PROBE |
 996                     ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_AGGREGATE |
 997                     ZIO_FLAG_TRYHARD;
 998 
 999                 if (spa_config_held(spa, SCL_ZIO, RW_WRITER)) {
1000                         /*
1001                          * vdev_cant_read and vdev_cant_write can only
1002                          * transition from TRUE to FALSE when we have the
1003                          * SCL_ZIO lock as writer; otherwise they can only
1004                          * transition from FALSE to TRUE.  This ensures that
1005                          * any zio looking at these values can assume that
1006                          * failures persist for the life of the I/O.  That's
1007                          * important because when a device has intermittent
1008                          * connectivity problems, we want to ensure that
1009                          * they're ascribed to the device (ENXIO) and not
1010                          * the zio (EIO).
1011                          *
1012                          * Since we hold SCL_ZIO as writer here, clear both
1013                          * values so the probe can reevaluate from first
1014                          * principles.
1015                          */
1016                         vps->vps_flags |= ZIO_FLAG_CONFIG_WRITER;
1017                         vd->vdev_cant_read = B_FALSE;
1018                         vd->vdev_cant_write = B_FALSE;
1019                 }
1020 
1021                 vd->vdev_probe_zio = pio = zio_null(NULL, spa, vd,
1022                     vdev_probe_done, vps,
1023                     vps->vps_flags | ZIO_FLAG_DONT_PROPAGATE);
1024 
1025                 /*
1026                  * We can't change the vdev state in this context, so we
1027                  * kick off an async task to do it on our behalf.
1028                  */
1029                 if (zio != NULL) {
1030                         vd->vdev_probe_wanted = B_TRUE;
1031                         spa_async_request(spa, SPA_ASYNC_PROBE);
1032                 }
1033         }
1034 
1035         if (zio != NULL)
1036                 zio_add_child(zio, pio);
1037 
1038         mutex_exit(&vd->vdev_probe_lock);
1039 
1040         if (vps == NULL) {
1041                 ASSERT(zio != NULL);
1042                 return (NULL);
1043         }
1044 
1045         for (int l = 1; l < VDEV_LABELS; l++) {
1046                 zio_nowait(zio_read_phys(pio, vd,
1047                     vdev_label_offset(vd->vdev_psize, l,
1048                     offsetof(vdev_label_t, vl_pad2)),
1049                     VDEV_PAD_SIZE, zio_buf_alloc(VDEV_PAD_SIZE),
1050                     ZIO_CHECKSUM_OFF, vdev_probe_done, vps,
1051                     ZIO_PRIORITY_SYNC_READ, vps->vps_flags, B_TRUE));
1052         }
1053 
1054         if (zio == NULL)
1055                 return (pio);
1056 
1057         zio_nowait(pio);
1058         return (NULL);
1059 }
1060 
1061 static void
1062 vdev_open_child(void *arg)
1063 {
1064         vdev_t *vd = arg;
1065 
1066         vd->vdev_open_thread = curthread;
1067         vd->vdev_open_error = vdev_open(vd);
1068         vd->vdev_open_thread = NULL;
1069 }
1070 
1071 boolean_t
1072 vdev_uses_zvols(vdev_t *vd)
1073 {
1074         if (vd->vdev_path && strncmp(vd->vdev_path, ZVOL_DIR,
1075             strlen(ZVOL_DIR)) == 0)
1076                 return (B_TRUE);
1077         for (int c = 0; c < vd->vdev_children; c++)
1078                 if (vdev_uses_zvols(vd->vdev_child[c]))
1079                         return (B_TRUE);
1080         return (B_FALSE);
1081 }
1082 
1083 void
1084 vdev_open_children(vdev_t *vd)
1085 {
1086         taskq_t *tq;
1087         int children = vd->vdev_children;
1088 
1089         /*
1090          * in order to handle pools on top of zvols, do the opens
1091          * in a single thread so that the same thread holds the
1092          * spa_namespace_lock
1093          */
1094         if (vdev_uses_zvols(vd)) {
1095                 for (int c = 0; c < children; c++)
1096                         vd->vdev_child[c]->vdev_open_error =
1097                             vdev_open(vd->vdev_child[c]);
1098                 return;
1099         }
1100         tq = taskq_create("vdev_open", children, minclsyspri,
1101             children, children, TASKQ_PREPOPULATE);
1102 
1103         for (int c = 0; c < children; c++)
1104                 VERIFY(taskq_dispatch(tq, vdev_open_child, vd->vdev_child[c],
1105                     TQ_SLEEP) != NULL);
1106 
1107         taskq_destroy(tq);
1108 }
1109 
1110 /*
1111  * Prepare a virtual device for access.
1112  */
1113 int
1114 vdev_open(vdev_t *vd)
1115 {
1116         spa_t *spa = vd->vdev_spa;
1117         int error;
1118         uint64_t osize = 0;
1119         uint64_t max_osize = 0;
1120         uint64_t asize, max_asize, psize;
1121         uint64_t ashift = 0;
1122 
1123         ASSERT(vd->vdev_open_thread == curthread ||
1124             spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
1125         ASSERT(vd->vdev_state == VDEV_STATE_CLOSED ||
1126             vd->vdev_state == VDEV_STATE_CANT_OPEN ||
1127             vd->vdev_state == VDEV_STATE_OFFLINE);
1128 
1129         vd->vdev_stat.vs_aux = VDEV_AUX_NONE;
1130         vd->vdev_cant_read = B_FALSE;
1131         vd->vdev_cant_write = B_FALSE;
1132         vd->vdev_min_asize = vdev_get_min_asize(vd);
1133 
1134         /*
1135          * If this vdev is not removed, check its fault status.  If it's
1136          * faulted, bail out of the open.
1137          */
1138         if (!vd->vdev_removed && vd->vdev_faulted) {
1139                 ASSERT(vd->vdev_children == 0);
1140                 ASSERT(vd->vdev_label_aux == VDEV_AUX_ERR_EXCEEDED ||
1141                     vd->vdev_label_aux == VDEV_AUX_EXTERNAL);
1142                 vdev_set_state(vd, B_TRUE, VDEV_STATE_FAULTED,
1143                     vd->vdev_label_aux);
1144                 return (SET_ERROR(ENXIO));
1145         } else if (vd->vdev_offline) {
1146                 ASSERT(vd->vdev_children == 0);
1147                 vdev_set_state(vd, B_TRUE, VDEV_STATE_OFFLINE, VDEV_AUX_NONE);
1148                 return (SET_ERROR(ENXIO));
1149         }
1150 
1151         error = vd->vdev_ops->vdev_op_open(vd, &osize, &max_osize, &ashift);
1152 
1153         /*
1154          * Reset the vdev_reopening flag so that we actually close
1155          * the vdev on error.
1156          */
1157         vd->vdev_reopening = B_FALSE;
1158         if (zio_injection_enabled && error == 0)
1159                 error = zio_handle_device_injection(vd, NULL, ENXIO);
1160 
1161         if (error) {
1162                 if (vd->vdev_removed &&
1163                     vd->vdev_stat.vs_aux != VDEV_AUX_OPEN_FAILED)
1164                         vd->vdev_removed = B_FALSE;
1165 
1166                 vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
1167                     vd->vdev_stat.vs_aux);
1168                 return (error);
1169         }
1170 
1171         vd->vdev_removed = B_FALSE;
1172 
1173         /*
1174          * Recheck the faulted flag now that we have confirmed that
1175          * the vdev is accessible.  If we're faulted, bail.
1176          */
1177         if (vd->vdev_faulted) {
1178                 ASSERT(vd->vdev_children == 0);
1179                 ASSERT(vd->vdev_label_aux == VDEV_AUX_ERR_EXCEEDED ||
1180                     vd->vdev_label_aux == VDEV_AUX_EXTERNAL);
1181                 vdev_set_state(vd, B_TRUE, VDEV_STATE_FAULTED,
1182                     vd->vdev_label_aux);
1183                 return (SET_ERROR(ENXIO));
1184         }
1185 
1186         if (vd->vdev_degraded) {
1187                 ASSERT(vd->vdev_children == 0);
1188                 vdev_set_state(vd, B_TRUE, VDEV_STATE_DEGRADED,
1189                     VDEV_AUX_ERR_EXCEEDED);
1190         } else {
1191                 vdev_set_state(vd, B_TRUE, VDEV_STATE_HEALTHY, 0);
1192         }
1193 
1194         /*
1195          * For hole or missing vdevs we just return success.
1196          */
1197         if (vd->vdev_ishole || vd->vdev_ops == &vdev_missing_ops)
1198                 return (0);
1199 
1200         for (int c = 0; c < vd->vdev_children; c++) {
1201                 if (vd->vdev_child[c]->vdev_state != VDEV_STATE_HEALTHY) {
1202                         vdev_set_state(vd, B_TRUE, VDEV_STATE_DEGRADED,
1203                             VDEV_AUX_NONE);
1204                         break;
1205                 }
1206         }
1207 
1208         osize = P2ALIGN(osize, (uint64_t)sizeof (vdev_label_t));
1209         max_osize = P2ALIGN(max_osize, (uint64_t)sizeof (vdev_label_t));
1210 
1211         if (vd->vdev_children == 0) {
1212                 if (osize < SPA_MINDEVSIZE) {
1213                         vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
1214                             VDEV_AUX_TOO_SMALL);
1215                         return (SET_ERROR(EOVERFLOW));
1216                 }
1217                 psize = osize;
1218                 asize = osize - (VDEV_LABEL_START_SIZE + VDEV_LABEL_END_SIZE);
1219                 max_asize = max_osize - (VDEV_LABEL_START_SIZE +
1220                     VDEV_LABEL_END_SIZE);
1221         } else {
1222                 if (vd->vdev_parent != NULL && osize < SPA_MINDEVSIZE -
1223                     (VDEV_LABEL_START_SIZE + VDEV_LABEL_END_SIZE)) {
1224                         vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
1225                             VDEV_AUX_TOO_SMALL);
1226                         return (SET_ERROR(EOVERFLOW));
1227                 }
1228                 psize = 0;
1229                 asize = osize;
1230                 max_asize = max_osize;
1231         }
1232 
1233         vd->vdev_psize = psize;
1234 
1235         /*
1236          * Make sure the allocatable size hasn't shrunk.
1237          */
1238         if (asize < vd->vdev_min_asize) {
1239                 vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
1240                     VDEV_AUX_BAD_LABEL);
1241                 return (SET_ERROR(EINVAL));
1242         }
1243 
1244         if (vd->vdev_asize == 0) {
1245                 /*
1246                  * This is the first-ever open, so use the computed values.
1247                  * For testing purposes, a higher ashift can be requested.
1248                  */
1249                 vd->vdev_asize = asize;
1250                 vd->vdev_max_asize = max_asize;
1251                 vd->vdev_ashift = MAX(ashift, vd->vdev_ashift);
1252         } else {
1253                 /*
1254                  * Detect if the alignment requirement has increased.
1255                  * We don't want to make the pool unavailable, just
1256                  * issue a warning instead.
1257                  */
1258                 if (ashift > vd->vdev_top->vdev_ashift &&
1259                     vd->vdev_ops->vdev_op_leaf) {
1260                         cmn_err(CE_WARN,
1261                             "Disk, '%s', has a block alignment that is "
1262                             "larger than the pool's alignment\n",
1263                             vd->vdev_path);
1264                 }
1265                 vd->vdev_max_asize = max_asize;
1266         }
1267 
1268         /*
1269          * If all children are healthy and the asize has increased,
1270          * then we've experienced dynamic LUN growth.  If automatic
1271          * expansion is enabled then use the additional space.
1272          */
1273         if (vd->vdev_state == VDEV_STATE_HEALTHY && asize > vd->vdev_asize &&
1274             (vd->vdev_expanding || spa->spa_autoexpand))
1275                 vd->vdev_asize = asize;
1276 
1277         vdev_set_min_asize(vd);
1278 
1279         /*
1280          * Ensure we can issue some IO before declaring the
1281          * vdev open for business.
1282          */
1283         if (vd->vdev_ops->vdev_op_leaf &&
1284             (error = zio_wait(vdev_probe(vd, NULL))) != 0) {
1285                 vdev_set_state(vd, B_TRUE, VDEV_STATE_FAULTED,
1286                     VDEV_AUX_ERR_EXCEEDED);
1287                 return (error);
1288         }
1289 
1290         /*
1291          * If a leaf vdev has a DTL, and seems healthy, then kick off a
1292          * resilver.  But don't do this if we are doing a reopen for a scrub,
1293          * since this would just restart the scrub we are already doing.
1294          */
1295         if (vd->vdev_ops->vdev_op_leaf && !spa->spa_scrub_reopen &&
1296             vdev_resilver_needed(vd, NULL, NULL))
1297                 spa_async_request(spa, SPA_ASYNC_RESILVER);
1298 
1299         return (0);
1300 }
1301 
1302 /*
1303  * Called once the vdevs are all opened, this routine validates the label
1304  * contents.  This needs to be done before vdev_load() so that we don't
1305  * inadvertently do repair I/Os to the wrong device.
1306  *
1307  * If 'strict' is false ignore the spa guid check. This is necessary because
1308  * if the machine crashed during a re-guid the new guid might have been written
1309  * to all of the vdev labels, but not the cached config. The strict check
1310  * will be performed when the pool is opened again using the mos config.
1311  *
1312  * This function will only return failure if one of the vdevs indicates that it
1313  * has since been destroyed or exported.  This is only possible if
1314  * /etc/zfs/zpool.cache was readonly at the time.  Otherwise, the vdev state
1315  * will be updated but the function will return 0.
1316  */
1317 int
1318 vdev_validate(vdev_t *vd, boolean_t strict)
1319 {
1320         spa_t *spa = vd->vdev_spa;
1321         nvlist_t *label;
1322         uint64_t guid = 0, top_guid;
1323         uint64_t state;
1324 
1325         for (int c = 0; c < vd->vdev_children; c++)
1326                 if (vdev_validate(vd->vdev_child[c], strict) != 0)
1327                         return (SET_ERROR(EBADF));
1328 
1329         /*
1330          * If the device has already failed, or was marked offline, don't do
1331          * any further validation.  Otherwise, label I/O will fail and we will
1332          * overwrite the previous state.
1333          */
1334         if (vd->vdev_ops->vdev_op_leaf && vdev_readable(vd)) {
1335                 uint64_t aux_guid = 0;
1336                 nvlist_t *nvl;
1337                 uint64_t txg = spa_last_synced_txg(spa) != 0 ?
1338                     spa_last_synced_txg(spa) : -1ULL;
1339 
1340                 if ((label = vdev_label_read_config(vd, txg)) == NULL) {
1341                         vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
1342                             VDEV_AUX_BAD_LABEL);
1343                         return (0);
1344                 }
1345 
1346                 /*
1347                  * Determine if this vdev has been split off into another
1348                  * pool.  If so, then refuse to open it.
1349                  */
1350                 if (nvlist_lookup_uint64(label, ZPOOL_CONFIG_SPLIT_GUID,
1351                     &aux_guid) == 0 && aux_guid == spa_guid(spa)) {
1352                         vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
1353                             VDEV_AUX_SPLIT_POOL);
1354                         nvlist_free(label);
1355                         return (0);
1356                 }
1357 
1358                 if (strict && (nvlist_lookup_uint64(label,
1359                     ZPOOL_CONFIG_POOL_GUID, &guid) != 0 ||
1360                     guid != spa_guid(spa))) {
1361                         vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
1362                             VDEV_AUX_CORRUPT_DATA);
1363                         nvlist_free(label);
1364                         return (0);
1365                 }
1366 
1367                 if (nvlist_lookup_nvlist(label, ZPOOL_CONFIG_VDEV_TREE, &nvl)
1368                     != 0 || nvlist_lookup_uint64(nvl, ZPOOL_CONFIG_ORIG_GUID,
1369                     &aux_guid) != 0)
1370                         aux_guid = 0;
1371 
1372                 /*
1373                  * If this vdev just became a top-level vdev because its
1374                  * sibling was detached, it will have adopted the parent's
1375                  * vdev guid -- but the label may or may not be on disk yet.
1376                  * Fortunately, either version of the label will have the
1377                  * same top guid, so if we're a top-level vdev, we can
1378                  * safely compare to that instead.
1379                  *
1380                  * If we split this vdev off instead, then we also check the
1381                  * original pool's guid.  We don't want to consider the vdev
1382                  * corrupt if it is partway through a split operation.
1383                  */
1384                 if (nvlist_lookup_uint64(label, ZPOOL_CONFIG_GUID,
1385                     &guid) != 0 ||
1386                     nvlist_lookup_uint64(label, ZPOOL_CONFIG_TOP_GUID,
1387                     &top_guid) != 0 ||
1388                     ((vd->vdev_guid != guid && vd->vdev_guid != aux_guid) &&
1389                     (vd->vdev_guid != top_guid || vd != vd->vdev_top))) {
1390                         vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
1391                             VDEV_AUX_CORRUPT_DATA);
1392                         nvlist_free(label);
1393                         return (0);
1394                 }
1395 
1396                 if (nvlist_lookup_uint64(label, ZPOOL_CONFIG_POOL_STATE,
1397                     &state) != 0) {
1398                         vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
1399                             VDEV_AUX_CORRUPT_DATA);
1400                         nvlist_free(label);
1401                         return (0);
1402                 }
1403 
1404                 nvlist_free(label);
1405 
1406                 /*
1407                  * If this is a verbatim import, no need to check the
1408                  * state of the pool.
1409                  */
1410                 if (!(spa->spa_import_flags & ZFS_IMPORT_VERBATIM) &&
1411                     spa_load_state(spa) == SPA_LOAD_OPEN &&
1412                     state != POOL_STATE_ACTIVE)
1413                         return (SET_ERROR(EBADF));
1414 
1415                 /*
1416                  * If we were able to open and validate a vdev that was
1417                  * previously marked permanently unavailable, clear that state
1418                  * now.
1419                  */
1420                 if (vd->vdev_not_present)
1421                         vd->vdev_not_present = 0;
1422         }
1423 
1424         return (0);
1425 }
1426 
1427 /*
1428  * Close a virtual device.
1429  */
1430 void
1431 vdev_close(vdev_t *vd)
1432 {
1433         spa_t *spa = vd->vdev_spa;
1434         vdev_t *pvd = vd->vdev_parent;
1435 
1436         ASSERT(spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
1437 
1438         /*
1439          * If our parent is reopening, then we are as well, unless we are
1440          * going offline.
1441          */
1442         if (pvd != NULL && pvd->vdev_reopening)
1443                 vd->vdev_reopening = (pvd->vdev_reopening && !vd->vdev_offline);
1444 
1445         vd->vdev_ops->vdev_op_close(vd);
1446 
1447         vdev_cache_purge(vd);
1448 
1449         /*
1450          * We record the previous state before we close it, so that if we are
1451          * doing a reopen(), we don't generate FMA ereports if we notice that
1452          * it's still faulted.
1453          */
1454         vd->vdev_prevstate = vd->vdev_state;
1455 
1456         if (vd->vdev_offline)
1457                 vd->vdev_state = VDEV_STATE_OFFLINE;
1458         else
1459                 vd->vdev_state = VDEV_STATE_CLOSED;
1460         vd->vdev_stat.vs_aux = VDEV_AUX_NONE;
1461 }
1462 
1463 void
1464 vdev_hold(vdev_t *vd)
1465 {
1466         spa_t *spa = vd->vdev_spa;
1467 
1468         ASSERT(spa_is_root(spa));
1469         if (spa->spa_state == POOL_STATE_UNINITIALIZED)
1470                 return;
1471 
1472         for (int c = 0; c < vd->vdev_children; c++)
1473                 vdev_hold(vd->vdev_child[c]);
1474 
1475         if (vd->vdev_ops->vdev_op_leaf)
1476                 vd->vdev_ops->vdev_op_hold(vd);
1477 }
1478 
1479 void
1480 vdev_rele(vdev_t *vd)
1481 {
1482         spa_t *spa = vd->vdev_spa;
1483 
1484         ASSERT(spa_is_root(spa));
1485         for (int c = 0; c < vd->vdev_children; c++)
1486                 vdev_rele(vd->vdev_child[c]);
1487 
1488         if (vd->vdev_ops->vdev_op_leaf)
1489                 vd->vdev_ops->vdev_op_rele(vd);
1490 }
1491 
1492 /*
1493  * Reopen all interior vdevs and any unopened leaves.  We don't actually
1494  * reopen leaf vdevs which had previously been opened as they might deadlock
1495  * on the spa_config_lock.  Instead we only obtain the leaf's physical size.
1496  * If the leaf has never been opened then open it, as usual.
1497  */
1498 void
1499 vdev_reopen(vdev_t *vd)
1500 {
1501         spa_t *spa = vd->vdev_spa;
1502 
1503         ASSERT(spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
1504 
1505         /* set the reopening flag unless we're taking the vdev offline */
1506         vd->vdev_reopening = !vd->vdev_offline;
1507         vdev_close(vd);
1508         (void) vdev_open(vd);
1509 
1510         /*
1511          * Call vdev_validate() here to make sure we have the same device.
1512          * Otherwise, a device with an invalid label could be successfully
1513          * opened in response to vdev_reopen().
1514          */
1515         if (vd->vdev_aux) {
1516                 (void) vdev_validate_aux(vd);
1517                 if (vdev_readable(vd) && vdev_writeable(vd) &&
1518                     vd->vdev_aux == &spa->spa_l2cache &&
1519                     !l2arc_vdev_present(vd))
1520                         l2arc_add_vdev(spa, vd);
1521         } else {
1522                 (void) vdev_validate(vd, B_TRUE);
1523         }
1524 
1525         /*
1526          * Reassess parent vdev's health.
1527          */
1528         vdev_propagate_state(vd);
1529 }
1530 
1531 int
1532 vdev_create(vdev_t *vd, uint64_t txg, boolean_t isreplacing)
1533 {
1534         int error;
1535 
1536         /*
1537          * Normally, partial opens (e.g. of a mirror) are allowed.
1538          * For a create, however, we want to fail the request if
1539          * there are any components we can't open.
1540          */
1541         error = vdev_open(vd);
1542 
1543         if (error || vd->vdev_state != VDEV_STATE_HEALTHY) {
1544                 vdev_close(vd);
1545                 return (error ? error : ENXIO);
1546         }
1547 
1548         /*
1549          * Recursively load DTLs and initialize all labels.
1550          */
1551         if ((error = vdev_dtl_load(vd)) != 0 ||
1552             (error = vdev_label_init(vd, txg, isreplacing ?
1553             VDEV_LABEL_REPLACE : VDEV_LABEL_CREATE)) != 0) {
1554                 vdev_close(vd);
1555                 return (error);
1556         }
1557 
1558         return (0);
1559 }
1560 
1561 void
1562 vdev_metaslab_set_size(vdev_t *vd)
1563 {
1564         /*
1565          * Aim for roughly 200 metaslabs per vdev.
1566          */
1567         vd->vdev_ms_shift = highbit64(vd->vdev_asize / 200);
1568         vd->vdev_ms_shift = MAX(vd->vdev_ms_shift, SPA_MAXBLOCKSHIFT);
1569 }
1570 
1571 void
1572 vdev_dirty(vdev_t *vd, int flags, void *arg, uint64_t txg)
1573 {
1574         ASSERT(vd == vd->vdev_top);
1575         ASSERT(!vd->vdev_ishole);
1576         ASSERT(ISP2(flags));
1577         ASSERT(spa_writeable(vd->vdev_spa));
1578 
1579         if (flags & VDD_METASLAB)
1580                 (void) txg_list_add(&vd->vdev_ms_list, arg, txg);
1581 
1582         if (flags & VDD_DTL)
1583                 (void) txg_list_add(&vd->vdev_dtl_list, arg, txg);
1584 
1585         (void) txg_list_add(&vd->vdev_spa->spa_vdev_txg_list, vd, txg);
1586 }
1587 
1588 void
1589 vdev_dirty_leaves(vdev_t *vd, int flags, uint64_t txg)
1590 {
1591         for (int c = 0; c < vd->vdev_children; c++)
1592                 vdev_dirty_leaves(vd->vdev_child[c], flags, txg);
1593 
1594         if (vd->vdev_ops->vdev_op_leaf)
1595                 vdev_dirty(vd->vdev_top, flags, vd, txg);
1596 }
1597 
1598 /*
1599  * DTLs.
1600  *
1601  * A vdev's DTL (dirty time log) is the set of transaction groups for which
1602  * the vdev has less than perfect replication.  There are four kinds of DTL:
1603  *
1604  * DTL_MISSING: txgs for which the vdev has no valid copies of the data
1605  *
1606  * DTL_PARTIAL: txgs for which data is available, but not fully replicated
1607  *
1608  * DTL_SCRUB: the txgs that could not be repaired by the last scrub; upon
1609  *      scrub completion, DTL_SCRUB replaces DTL_MISSING in the range of
1610  *      txgs that was scrubbed.
1611  *
1612  * DTL_OUTAGE: txgs which cannot currently be read, whether due to
1613  *      persistent errors or just some device being offline.
1614  *      Unlike the other three, the DTL_OUTAGE map is not generally
1615  *      maintained; it's only computed when needed, typically to
1616  *      determine whether a device can be detached.
1617  *
1618  * For leaf vdevs, DTL_MISSING and DTL_PARTIAL are identical: the device
1619  * either has the data or it doesn't.
1620  *
1621  * For interior vdevs such as mirror and RAID-Z the picture is more complex.
1622  * A vdev's DTL_PARTIAL is the union of its children's DTL_PARTIALs, because
1623  * if any child is less than fully replicated, then so is its parent.
1624  * A vdev's DTL_MISSING is a modified union of its children's DTL_MISSINGs,
1625  * comprising only those txgs which appear in 'maxfaults' or more children;
1626  * those are the txgs we don't have enough replication to read.  For example,
1627  * double-parity RAID-Z can tolerate up to two missing devices (maxfaults == 2);
1628  * thus, its DTL_MISSING consists of the set of txgs that appear in more than
1629  * two child DTL_MISSING maps.
1630  *
1631  * It should be clear from the above that to compute the DTLs and outage maps
1632  * for all vdevs, it suffices to know just the leaf vdevs' DTL_MISSING maps.
1633  * Therefore, that is all we keep on disk.  When loading the pool, or after
1634  * a configuration change, we generate all other DTLs from first principles.
1635  */
1636 void
1637 vdev_dtl_dirty(vdev_t *vd, vdev_dtl_type_t t, uint64_t txg, uint64_t size)
1638 {
1639         range_tree_t *rt = vd->vdev_dtl[t];
1640 
1641         ASSERT(t < DTL_TYPES);
1642         ASSERT(vd != vd->vdev_spa->spa_root_vdev);
1643         ASSERT(spa_writeable(vd->vdev_spa));
1644 
1645         mutex_enter(rt->rt_lock);
1646         if (!range_tree_contains(rt, txg, size))
1647                 range_tree_add(rt, txg, size);
1648         mutex_exit(rt->rt_lock);
1649 }
1650 
1651 boolean_t
1652 vdev_dtl_contains(vdev_t *vd, vdev_dtl_type_t t, uint64_t txg, uint64_t size)
1653 {
1654         range_tree_t *rt = vd->vdev_dtl[t];
1655         boolean_t dirty = B_FALSE;
1656 
1657         ASSERT(t < DTL_TYPES);
1658         ASSERT(vd != vd->vdev_spa->spa_root_vdev);
1659 
1660         mutex_enter(rt->rt_lock);
1661         if (range_tree_space(rt) != 0)
1662                 dirty = range_tree_contains(rt, txg, size);
1663         mutex_exit(rt->rt_lock);
1664 
1665         return (dirty);
1666 }
1667 
1668 boolean_t
1669 vdev_dtl_empty(vdev_t *vd, vdev_dtl_type_t t)
1670 {
1671         range_tree_t *rt = vd->vdev_dtl[t];
1672         boolean_t empty;
1673 
1674         mutex_enter(rt->rt_lock);
1675         empty = (range_tree_space(rt) == 0);
1676         mutex_exit(rt->rt_lock);
1677 
1678         return (empty);
1679 }
1680 
1681 /*
1682  * Returns the lowest txg in the DTL range.
1683  */
1684 static uint64_t
1685 vdev_dtl_min(vdev_t *vd)
1686 {
1687         range_seg_t *rs;
1688 
1689         ASSERT(MUTEX_HELD(&vd->vdev_dtl_lock));
1690         ASSERT3U(range_tree_space(vd->vdev_dtl[DTL_MISSING]), !=, 0);
1691         ASSERT0(vd->vdev_children);
1692 
1693         rs = avl_first(&vd->vdev_dtl[DTL_MISSING]->rt_root);
1694         return (rs->rs_start - 1);
1695 }
1696 
1697 /*
1698  * Returns the highest txg in the DTL.
1699  */
1700 static uint64_t
1701 vdev_dtl_max(vdev_t *vd)
1702 {
1703         range_seg_t *rs;
1704 
1705         ASSERT(MUTEX_HELD(&vd->vdev_dtl_lock));
1706         ASSERT3U(range_tree_space(vd->vdev_dtl[DTL_MISSING]), !=, 0);
1707         ASSERT0(vd->vdev_children);
1708 
1709         rs = avl_last(&vd->vdev_dtl[DTL_MISSING]->rt_root);
1710         return (rs->rs_end);
1711 }
1712 
1713 /*
1714  * Determine if a resilvering vdev should remove any DTL entries from
1715  * its range. If the vdev was resilvering for the entire duration of the
1716  * scan then it should excise that range from its DTLs. Otherwise, this
1717  * vdev is considered partially resilvered and should leave its DTL
1718  * entries intact. The comment in vdev_dtl_reassess() describes how we
1719  * excise the DTLs.
1720  */
1721 static boolean_t
1722 vdev_dtl_should_excise(vdev_t *vd)
1723 {
1724         spa_t *spa = vd->vdev_spa;
1725         dsl_scan_t *scn = spa->spa_dsl_pool->dp_scan;
1726 
1727         ASSERT0(scn->scn_phys.scn_errors);
1728         ASSERT0(vd->vdev_children);
1729 
1730         if (vd->vdev_resilver_txg == 0 ||
1731             range_tree_space(vd->vdev_dtl[DTL_MISSING]) == 0)
1732                 return (B_TRUE);
1733 
1734         /*
1735          * When a resilver is initiated the scan will assign the scn_max_txg
1736          * value to the highest txg value that exists in all DTLs. If this
1737          * device's max DTL is not part of this scan (i.e. it is not in
1738          * the range (scn_min_txg, scn_max_txg] then it is not eligible
1739          * for excision.
1740          */
1741         if (vdev_dtl_max(vd) <= scn->scn_phys.scn_max_txg) {
1742                 ASSERT3U(scn->scn_phys.scn_min_txg, <=, vdev_dtl_min(vd));
1743                 ASSERT3U(scn->scn_phys.scn_min_txg, <, vd->vdev_resilver_txg);
1744                 ASSERT3U(vd->vdev_resilver_txg, <=, scn->scn_phys.scn_max_txg);
1745                 return (B_TRUE);
1746         }
1747         return (B_FALSE);
1748 }
1749 
1750 /*
1751  * Reassess DTLs after a config change or scrub completion.
1752  */
1753 void
1754 vdev_dtl_reassess(vdev_t *vd, uint64_t txg, uint64_t scrub_txg, int scrub_done)
1755 {
1756         spa_t *spa = vd->vdev_spa;
1757         avl_tree_t reftree;
1758         int minref;
1759 
1760         ASSERT(spa_config_held(spa, SCL_ALL, RW_READER) != 0);
1761 
1762         for (int c = 0; c < vd->vdev_children; c++)
1763                 vdev_dtl_reassess(vd->vdev_child[c], txg,
1764                     scrub_txg, scrub_done);
1765 
1766         if (vd == spa->spa_root_vdev || vd->vdev_ishole || vd->vdev_aux)
1767                 return;
1768 
1769         if (vd->vdev_ops->vdev_op_leaf) {
1770                 dsl_scan_t *scn = spa->spa_dsl_pool->dp_scan;
1771 
1772                 mutex_enter(&vd->vdev_dtl_lock);
1773 
1774                 /*
1775                  * If we've completed a scan cleanly then determine
1776                  * if this vdev should remove any DTLs. We only want to
1777                  * excise regions on vdevs that were available during
1778                  * the entire duration of this scan.
1779                  */
1780                 if (scrub_txg != 0 &&
1781                     (spa->spa_scrub_started ||
1782                     (scn != NULL && scn->scn_phys.scn_errors == 0)) &&
1783                     vdev_dtl_should_excise(vd)) {
1784                         /*
1785                          * We completed a scrub up to scrub_txg.  If we
1786                          * did it without rebooting, then the scrub dtl
1787                          * will be valid, so excise the old region and
1788                          * fold in the scrub dtl.  Otherwise, leave the
1789                          * dtl as-is if there was an error.
1790                          *
1791                          * There's little trick here: to excise the beginning
1792                          * of the DTL_MISSING map, we put it into a reference
1793                          * tree and then add a segment with refcnt -1 that
1794                          * covers the range [0, scrub_txg).  This means
1795                          * that each txg in that range has refcnt -1 or 0.
1796                          * We then add DTL_SCRUB with a refcnt of 2, so that
1797                          * entries in the range [0, scrub_txg) will have a
1798                          * positive refcnt -- either 1 or 2.  We then convert
1799                          * the reference tree into the new DTL_MISSING map.
1800                          */
1801                         space_reftree_create(&reftree);
1802                         space_reftree_add_map(&reftree,
1803                             vd->vdev_dtl[DTL_MISSING], 1);
1804                         space_reftree_add_seg(&reftree, 0, scrub_txg, -1);
1805                         space_reftree_add_map(&reftree,
1806                             vd->vdev_dtl[DTL_SCRUB], 2);
1807                         space_reftree_generate_map(&reftree,
1808                             vd->vdev_dtl[DTL_MISSING], 1);
1809                         space_reftree_destroy(&reftree);
1810                 }
1811                 range_tree_vacate(vd->vdev_dtl[DTL_PARTIAL], NULL, NULL);
1812                 range_tree_walk(vd->vdev_dtl[DTL_MISSING],
1813                     range_tree_add, vd->vdev_dtl[DTL_PARTIAL]);
1814                 if (scrub_done)
1815                         range_tree_vacate(vd->vdev_dtl[DTL_SCRUB], NULL, NULL);
1816                 range_tree_vacate(vd->vdev_dtl[DTL_OUTAGE], NULL, NULL);
1817                 if (!vdev_readable(vd))
1818                         range_tree_add(vd->vdev_dtl[DTL_OUTAGE], 0, -1ULL);
1819                 else
1820                         range_tree_walk(vd->vdev_dtl[DTL_MISSING],
1821                             range_tree_add, vd->vdev_dtl[DTL_OUTAGE]);
1822 
1823                 /*
1824                  * If the vdev was resilvering and no longer has any
1825                  * DTLs then reset its resilvering flag.
1826                  */
1827                 if (vd->vdev_resilver_txg != 0 &&
1828                     range_tree_space(vd->vdev_dtl[DTL_MISSING]) == 0 &&
1829                     range_tree_space(vd->vdev_dtl[DTL_OUTAGE]) == 0)
1830                         vd->vdev_resilver_txg = 0;
1831 
1832                 mutex_exit(&vd->vdev_dtl_lock);
1833 
1834                 if (txg != 0)
1835                         vdev_dirty(vd->vdev_top, VDD_DTL, vd, txg);
1836                 return;
1837         }
1838 
1839         mutex_enter(&vd->vdev_dtl_lock);
1840         for (int t = 0; t < DTL_TYPES; t++) {
1841                 /* account for child's outage in parent's missing map */
1842                 int s = (t == DTL_MISSING) ? DTL_OUTAGE: t;
1843                 if (t == DTL_SCRUB)
1844                         continue;                       /* leaf vdevs only */
1845                 if (t == DTL_PARTIAL)
1846                         minref = 1;                     /* i.e. non-zero */
1847                 else if (vd->vdev_nparity != 0)
1848                         minref = vd->vdev_nparity + 1;       /* RAID-Z */
1849                 else
1850                         minref = vd->vdev_children;  /* any kind of mirror */
1851                 space_reftree_create(&reftree);
1852                 for (int c = 0; c < vd->vdev_children; c++) {
1853                         vdev_t *cvd = vd->vdev_child[c];
1854                         mutex_enter(&cvd->vdev_dtl_lock);
1855                         space_reftree_add_map(&reftree, cvd->vdev_dtl[s], 1);
1856                         mutex_exit(&cvd->vdev_dtl_lock);
1857                 }
1858                 space_reftree_generate_map(&reftree, vd->vdev_dtl[t], minref);
1859                 space_reftree_destroy(&reftree);
1860         }
1861         mutex_exit(&vd->vdev_dtl_lock);
1862 }
1863 
1864 int
1865 vdev_dtl_load(vdev_t *vd)
1866 {
1867         spa_t *spa = vd->vdev_spa;
1868         objset_t *mos = spa->spa_meta_objset;
1869         int error = 0;
1870 
1871         if (vd->vdev_ops->vdev_op_leaf && vd->vdev_dtl_object != 0) {
1872                 ASSERT(!vd->vdev_ishole);
1873 
1874                 error = space_map_open(&vd->vdev_dtl_sm, mos,
1875                     vd->vdev_dtl_object, 0, -1ULL, 0, &vd->vdev_dtl_lock);
1876                 if (error)
1877                         return (error);
1878                 ASSERT(vd->vdev_dtl_sm != NULL);
1879 
1880                 mutex_enter(&vd->vdev_dtl_lock);
1881 
1882                 /*
1883                  * Now that we've opened the space_map we need to update
1884                  * the in-core DTL.
1885                  */
1886                 space_map_update(vd->vdev_dtl_sm);
1887 
1888                 error = space_map_load(vd->vdev_dtl_sm,
1889                     vd->vdev_dtl[DTL_MISSING], SM_ALLOC);
1890                 mutex_exit(&vd->vdev_dtl_lock);
1891 
1892                 return (error);
1893         }
1894 
1895         for (int c = 0; c < vd->vdev_children; c++) {
1896                 error = vdev_dtl_load(vd->vdev_child[c]);
1897                 if (error != 0)
1898                         break;
1899         }
1900 
1901         return (error);
1902 }
1903 
1904 void
1905 vdev_dtl_sync(vdev_t *vd, uint64_t txg)
1906 {
1907         spa_t *spa = vd->vdev_spa;
1908         range_tree_t *rt = vd->vdev_dtl[DTL_MISSING];
1909         objset_t *mos = spa->spa_meta_objset;
1910         range_tree_t *rtsync;
1911         kmutex_t rtlock;
1912         dmu_tx_t *tx;
1913         uint64_t object = space_map_object(vd->vdev_dtl_sm);
1914 
1915         ASSERT(!vd->vdev_ishole);
1916         ASSERT(vd->vdev_ops->vdev_op_leaf);
1917 
1918         tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg);
1919 
1920         if (vd->vdev_detached || vd->vdev_top->vdev_removing) {
1921                 mutex_enter(&vd->vdev_dtl_lock);
1922                 space_map_free(vd->vdev_dtl_sm, tx);
1923                 space_map_close(vd->vdev_dtl_sm);
1924                 vd->vdev_dtl_sm = NULL;
1925                 mutex_exit(&vd->vdev_dtl_lock);
1926                 dmu_tx_commit(tx);
1927                 return;
1928         }
1929 
1930         if (vd->vdev_dtl_sm == NULL) {
1931                 uint64_t new_object;
1932 
1933                 new_object = space_map_alloc(mos, tx);
1934                 VERIFY3U(new_object, !=, 0);
1935 
1936                 VERIFY0(space_map_open(&vd->vdev_dtl_sm, mos, new_object,
1937                     0, -1ULL, 0, &vd->vdev_dtl_lock));
1938                 ASSERT(vd->vdev_dtl_sm != NULL);
1939         }
1940 
1941         mutex_init(&rtlock, NULL, MUTEX_DEFAULT, NULL);
1942 
1943         rtsync = range_tree_create(NULL, NULL, &rtlock);
1944 
1945         mutex_enter(&rtlock);
1946 
1947         mutex_enter(&vd->vdev_dtl_lock);
1948         range_tree_walk(rt, range_tree_add, rtsync);
1949         mutex_exit(&vd->vdev_dtl_lock);
1950 
1951         space_map_truncate(vd->vdev_dtl_sm, tx);
1952         space_map_write(vd->vdev_dtl_sm, rtsync, SM_ALLOC, tx);
1953         range_tree_vacate(rtsync, NULL, NULL);
1954 
1955         range_tree_destroy(rtsync);
1956 
1957         mutex_exit(&rtlock);
1958         mutex_destroy(&rtlock);
1959 
1960         /*
1961          * If the object for the space map has changed then dirty
1962          * the top level so that we update the config.
1963          */
1964         if (object != space_map_object(vd->vdev_dtl_sm)) {
1965                 zfs_dbgmsg("txg %llu, spa %s, DTL old object %llu, "
1966                     "new object %llu", txg, spa_name(spa), object,
1967                     space_map_object(vd->vdev_dtl_sm));
1968                 vdev_config_dirty(vd->vdev_top);
1969         }
1970 
1971         dmu_tx_commit(tx);
1972 
1973         mutex_enter(&vd->vdev_dtl_lock);
1974         space_map_update(vd->vdev_dtl_sm);
1975         mutex_exit(&vd->vdev_dtl_lock);
1976 }
1977 
1978 /*
1979  * Determine whether the specified vdev can be offlined/detached/removed
1980  * without losing data.
1981  */
1982 boolean_t
1983 vdev_dtl_required(vdev_t *vd)
1984 {
1985         spa_t *spa = vd->vdev_spa;
1986         vdev_t *tvd = vd->vdev_top;
1987         uint8_t cant_read = vd->vdev_cant_read;
1988         boolean_t required;
1989 
1990         ASSERT(spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
1991 
1992         if (vd == spa->spa_root_vdev || vd == tvd)
1993                 return (B_TRUE);
1994 
1995         /*
1996          * Temporarily mark the device as unreadable, and then determine
1997          * whether this results in any DTL outages in the top-level vdev.
1998          * If not, we can safely offline/detach/remove the device.
1999          */
2000         vd->vdev_cant_read = B_TRUE;
2001         vdev_dtl_reassess(tvd, 0, 0, B_FALSE);
2002         required = !vdev_dtl_empty(tvd, DTL_OUTAGE);
2003         vd->vdev_cant_read = cant_read;
2004         vdev_dtl_reassess(tvd, 0, 0, B_FALSE);
2005 
2006         if (!required && zio_injection_enabled)
2007                 required = !!zio_handle_device_injection(vd, NULL, ECHILD);
2008 
2009         return (required);
2010 }
2011 
2012 /*
2013  * Determine if resilver is needed, and if so the txg range.
2014  */
2015 boolean_t
2016 vdev_resilver_needed(vdev_t *vd, uint64_t *minp, uint64_t *maxp)
2017 {
2018         boolean_t needed = B_FALSE;
2019         uint64_t thismin = UINT64_MAX;
2020         uint64_t thismax = 0;
2021 
2022         if (vd->vdev_children == 0) {
2023                 mutex_enter(&vd->vdev_dtl_lock);
2024                 if (range_tree_space(vd->vdev_dtl[DTL_MISSING]) != 0 &&
2025                     vdev_writeable(vd)) {
2026 
2027                         thismin = vdev_dtl_min(vd);
2028                         thismax = vdev_dtl_max(vd);
2029                         needed = B_TRUE;
2030                 }
2031                 mutex_exit(&vd->vdev_dtl_lock);
2032         } else {
2033                 for (int c = 0; c < vd->vdev_children; c++) {
2034                         vdev_t *cvd = vd->vdev_child[c];
2035                         uint64_t cmin, cmax;
2036 
2037                         if (vdev_resilver_needed(cvd, &cmin, &cmax)) {
2038                                 thismin = MIN(thismin, cmin);
2039                                 thismax = MAX(thismax, cmax);
2040                                 needed = B_TRUE;
2041                         }
2042                 }
2043         }
2044 
2045         if (needed && minp) {
2046                 *minp = thismin;
2047                 *maxp = thismax;
2048         }
2049         return (needed);
2050 }
2051 
2052 void
2053 vdev_load(vdev_t *vd)
2054 {
2055         /*
2056          * Recursively load all children.
2057          */
2058         for (int c = 0; c < vd->vdev_children; c++)
2059                 vdev_load(vd->vdev_child[c]);
2060 
2061         /*
2062          * If this is a top-level vdev, initialize its metaslabs.
2063          */
2064         if (vd == vd->vdev_top && !vd->vdev_ishole &&
2065             (vd->vdev_ashift == 0 || vd->vdev_asize == 0 ||
2066             vdev_metaslab_init(vd, 0) != 0))
2067                 vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
2068                     VDEV_AUX_CORRUPT_DATA);
2069 
2070         /*
2071          * If this is a leaf vdev, load its DTL.
2072          */
2073         if (vd->vdev_ops->vdev_op_leaf && vdev_dtl_load(vd) != 0)
2074                 vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
2075                     VDEV_AUX_CORRUPT_DATA);
2076 }
2077 
2078 /*
2079  * The special vdev case is used for hot spares and l2cache devices.  Its
2080  * sole purpose it to set the vdev state for the associated vdev.  To do this,
2081  * we make sure that we can open the underlying device, then try to read the
2082  * label, and make sure that the label is sane and that it hasn't been
2083  * repurposed to another pool.
2084  */
2085 int
2086 vdev_validate_aux(vdev_t *vd)
2087 {
2088         nvlist_t *label;
2089         uint64_t guid, version;
2090         uint64_t state;
2091 
2092         if (!vdev_readable(vd))
2093                 return (0);
2094 
2095         if ((label = vdev_label_read_config(vd, -1ULL)) == NULL) {
2096                 vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
2097                     VDEV_AUX_CORRUPT_DATA);
2098                 return (-1);
2099         }
2100 
2101         if (nvlist_lookup_uint64(label, ZPOOL_CONFIG_VERSION, &version) != 0 ||
2102             !SPA_VERSION_IS_SUPPORTED(version) ||
2103             nvlist_lookup_uint64(label, ZPOOL_CONFIG_GUID, &guid) != 0 ||
2104             guid != vd->vdev_guid ||
2105             nvlist_lookup_uint64(label, ZPOOL_CONFIG_POOL_STATE, &state) != 0) {
2106                 vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
2107                     VDEV_AUX_CORRUPT_DATA);
2108                 nvlist_free(label);
2109                 return (-1);
2110         }
2111 
2112         /*
2113          * We don't actually check the pool state here.  If it's in fact in
2114          * use by another pool, we update this fact on the fly when requested.
2115          */
2116         nvlist_free(label);
2117         return (0);
2118 }
2119 
2120 void
2121 vdev_remove(vdev_t *vd, uint64_t txg)
2122 {
2123         spa_t *spa = vd->vdev_spa;
2124         objset_t *mos = spa->spa_meta_objset;
2125         dmu_tx_t *tx;
2126 
2127         tx = dmu_tx_create_assigned(spa_get_dsl(spa), txg);
2128 
2129         if (vd->vdev_ms != NULL) {
2130                 for (int m = 0; m < vd->vdev_ms_count; m++) {
2131                         metaslab_t *msp = vd->vdev_ms[m];
2132 
2133                         if (msp == NULL || msp->ms_sm == NULL)
2134                                 continue;
2135 
2136                         mutex_enter(&msp->ms_lock);
2137                         VERIFY0(space_map_allocated(msp->ms_sm));
2138                         space_map_free(msp->ms_sm, tx);
2139                         space_map_close(msp->ms_sm);
2140                         msp->ms_sm = NULL;
2141                         mutex_exit(&msp->ms_lock);
2142                 }
2143         }
2144 
2145         if (vd->vdev_ms_array) {
2146                 (void) dmu_object_free(mos, vd->vdev_ms_array, tx);
2147                 vd->vdev_ms_array = 0;
2148         }
2149         dmu_tx_commit(tx);
2150 }
2151 
2152 void
2153 vdev_sync_done(vdev_t *vd, uint64_t txg)
2154 {
2155         metaslab_t *msp;
2156         boolean_t reassess = !txg_list_empty(&vd->vdev_ms_list, TXG_CLEAN(txg));
2157 
2158         ASSERT(!vd->vdev_ishole);
2159 
2160         while (msp = txg_list_remove(&vd->vdev_ms_list, TXG_CLEAN(txg)))
2161                 metaslab_sync_done(msp, txg);
2162 
2163         if (reassess)
2164                 metaslab_sync_reassess(vd->vdev_mg);
2165 }
2166 
2167 void
2168 vdev_sync(vdev_t *vd, uint64_t txg)
2169 {
2170         spa_t *spa = vd->vdev_spa;
2171         vdev_t *lvd;
2172         metaslab_t *msp;
2173         dmu_tx_t *tx;
2174 
2175         ASSERT(!vd->vdev_ishole);
2176 
2177         if (vd->vdev_ms_array == 0 && vd->vdev_ms_shift != 0) {
2178                 ASSERT(vd == vd->vdev_top);
2179                 tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg);
2180                 vd->vdev_ms_array = dmu_object_alloc(spa->spa_meta_objset,
2181                     DMU_OT_OBJECT_ARRAY, 0, DMU_OT_NONE, 0, tx);
2182                 ASSERT(vd->vdev_ms_array != 0);
2183                 vdev_config_dirty(vd);
2184                 dmu_tx_commit(tx);
2185         }
2186 
2187         /*
2188          * Remove the metadata associated with this vdev once it's empty.
2189          */
2190         if (vd->vdev_stat.vs_alloc == 0 && vd->vdev_removing)
2191                 vdev_remove(vd, txg);
2192 
2193         while ((msp = txg_list_remove(&vd->vdev_ms_list, txg)) != NULL) {
2194                 metaslab_sync(msp, txg);
2195                 (void) txg_list_add(&vd->vdev_ms_list, msp, TXG_CLEAN(txg));
2196         }
2197 
2198         while ((lvd = txg_list_remove(&vd->vdev_dtl_list, txg)) != NULL)
2199                 vdev_dtl_sync(lvd, txg);
2200 
2201         (void) txg_list_add(&spa->spa_vdev_txg_list, vd, TXG_CLEAN(txg));
2202 }
2203 
2204 uint64_t
2205 vdev_psize_to_asize(vdev_t *vd, uint64_t psize)
2206 {
2207         return (vd->vdev_ops->vdev_op_asize(vd, psize));
2208 }
2209 
2210 /*
2211  * Mark the given vdev faulted.  A faulted vdev behaves as if the device could
2212  * not be opened, and no I/O is attempted.
2213  */
2214 int
2215 vdev_fault(spa_t *spa, uint64_t guid, vdev_aux_t aux)
2216 {
2217         vdev_t *vd, *tvd;
2218 
2219         spa_vdev_state_enter(spa, SCL_NONE);
2220 
2221         if ((vd = spa_lookup_by_guid(spa, guid, B_TRUE)) == NULL)
2222                 return (spa_vdev_state_exit(spa, NULL, ENODEV));
2223 
2224         if (!vd->vdev_ops->vdev_op_leaf)
2225                 return (spa_vdev_state_exit(spa, NULL, ENOTSUP));
2226 
2227         tvd = vd->vdev_top;
2228 
2229         /*
2230          * We don't directly use the aux state here, but if we do a
2231          * vdev_reopen(), we need this value to be present to remember why we
2232          * were faulted.
2233          */
2234         vd->vdev_label_aux = aux;
2235 
2236         /*
2237          * Faulted state takes precedence over degraded.
2238          */
2239         vd->vdev_delayed_close = B_FALSE;
2240         vd->vdev_faulted = 1ULL;
2241         vd->vdev_degraded = 0ULL;
2242         vdev_set_state(vd, B_FALSE, VDEV_STATE_FAULTED, aux);
2243 
2244         /*
2245          * If this device has the only valid copy of the data, then
2246          * back off and simply mark the vdev as degraded instead.
2247          */
2248         if (!tvd->vdev_islog && vd->vdev_aux == NULL && vdev_dtl_required(vd)) {
2249                 vd->vdev_degraded = 1ULL;
2250                 vd->vdev_faulted = 0ULL;
2251 
2252                 /*
2253                  * If we reopen the device and it's not dead, only then do we
2254                  * mark it degraded.
2255                  */
2256                 vdev_reopen(tvd);
2257 
2258                 if (vdev_readable(vd))
2259                         vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED, aux);
2260         }
2261 
2262         return (spa_vdev_state_exit(spa, vd, 0));
2263 }
2264 
2265 /*
2266  * Mark the given vdev degraded.  A degraded vdev is purely an indication to the
2267  * user that something is wrong.  The vdev continues to operate as normal as far
2268  * as I/O is concerned.
2269  */
2270 int
2271 vdev_degrade(spa_t *spa, uint64_t guid, vdev_aux_t aux)
2272 {
2273         vdev_t *vd;
2274 
2275         spa_vdev_state_enter(spa, SCL_NONE);
2276 
2277         if ((vd = spa_lookup_by_guid(spa, guid, B_TRUE)) == NULL)
2278                 return (spa_vdev_state_exit(spa, NULL, ENODEV));
2279 
2280         if (!vd->vdev_ops->vdev_op_leaf)
2281                 return (spa_vdev_state_exit(spa, NULL, ENOTSUP));
2282 
2283         /*
2284          * If the vdev is already faulted, then don't do anything.
2285          */
2286         if (vd->vdev_faulted || vd->vdev_degraded)
2287                 return (spa_vdev_state_exit(spa, NULL, 0));
2288 
2289         vd->vdev_degraded = 1ULL;
2290         if (!vdev_is_dead(vd))
2291                 vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED,
2292                     aux);
2293 
2294         return (spa_vdev_state_exit(spa, vd, 0));
2295 }
2296 
2297 /*
2298  * Online the given vdev.
2299  *
2300  * If 'ZFS_ONLINE_UNSPARE' is set, it implies two things.  First, any attached
2301  * spare device should be detached when the device finishes resilvering.
2302  * Second, the online should be treated like a 'test' online case, so no FMA
2303  * events are generated if the device fails to open.
2304  */
2305 int
2306 vdev_online(spa_t *spa, uint64_t guid, uint64_t flags, vdev_state_t *newstate)
2307 {
2308         vdev_t *vd, *tvd, *pvd, *rvd = spa->spa_root_vdev;
2309 
2310         spa_vdev_state_enter(spa, SCL_NONE);
2311 
2312         if ((vd = spa_lookup_by_guid(spa, guid, B_TRUE)) == NULL)
2313                 return (spa_vdev_state_exit(spa, NULL, ENODEV));
2314 
2315         if (!vd->vdev_ops->vdev_op_leaf)
2316                 return (spa_vdev_state_exit(spa, NULL, ENOTSUP));
2317 
2318         tvd = vd->vdev_top;
2319         vd->vdev_offline = B_FALSE;
2320         vd->vdev_tmpoffline = B_FALSE;
2321         vd->vdev_checkremove = !!(flags & ZFS_ONLINE_CHECKREMOVE);
2322         vd->vdev_forcefault = !!(flags & ZFS_ONLINE_FORCEFAULT);
2323 
2324         /* XXX - L2ARC 1.0 does not support expansion */
2325         if (!vd->vdev_aux) {
2326                 for (pvd = vd; pvd != rvd; pvd = pvd->vdev_parent)
2327                         pvd->vdev_expanding = !!(flags & ZFS_ONLINE_EXPAND);
2328         }
2329 
2330         vdev_reopen(tvd);
2331         vd->vdev_checkremove = vd->vdev_forcefault = B_FALSE;
2332 
2333         if (!vd->vdev_aux) {
2334                 for (pvd = vd; pvd != rvd; pvd = pvd->vdev_parent)
2335                         pvd->vdev_expanding = B_FALSE;
2336         }
2337 
2338         if (newstate)
2339                 *newstate = vd->vdev_state;
2340         if ((flags & ZFS_ONLINE_UNSPARE) &&
2341             !vdev_is_dead(vd) && vd->vdev_parent &&
2342             vd->vdev_parent->vdev_ops == &vdev_spare_ops &&
2343             vd->vdev_parent->vdev_child[0] == vd)
2344                 vd->vdev_unspare = B_TRUE;
2345 
2346         if ((flags & ZFS_ONLINE_EXPAND) || spa->spa_autoexpand) {
2347 
2348                 /* XXX - L2ARC 1.0 does not support expansion */
2349                 if (vd->vdev_aux)
2350                         return (spa_vdev_state_exit(spa, vd, ENOTSUP));
2351                 spa_async_request(spa, SPA_ASYNC_CONFIG_UPDATE);
2352         }
2353         return (spa_vdev_state_exit(spa, vd, 0));
2354 }
2355 
2356 static int
2357 vdev_offline_locked(spa_t *spa, uint64_t guid, uint64_t flags)
2358 {
2359         vdev_t *vd, *tvd;
2360         int error = 0;
2361         uint64_t generation;
2362         metaslab_group_t *mg;
2363 
2364 top:
2365         spa_vdev_state_enter(spa, SCL_ALLOC);
2366 
2367         if ((vd = spa_lookup_by_guid(spa, guid, B_TRUE)) == NULL)
2368                 return (spa_vdev_state_exit(spa, NULL, ENODEV));
2369 
2370         if (!vd->vdev_ops->vdev_op_leaf)
2371                 return (spa_vdev_state_exit(spa, NULL, ENOTSUP));
2372 
2373         tvd = vd->vdev_top;
2374         mg = tvd->vdev_mg;
2375         generation = spa->spa_config_generation + 1;
2376 
2377         /*
2378          * If the device isn't already offline, try to offline it.
2379          */
2380         if (!vd->vdev_offline) {
2381                 /*
2382                  * If this device has the only valid copy of some data,
2383                  * don't allow it to be offlined. Log devices are always
2384                  * expendable.
2385                  */
2386                 if (!tvd->vdev_islog && vd->vdev_aux == NULL &&
2387                     vdev_dtl_required(vd))
2388                         return (spa_vdev_state_exit(spa, NULL, EBUSY));
2389 
2390                 /*
2391                  * If the top-level is a slog and it has had allocations
2392                  * then proceed.  We check that the vdev's metaslab group
2393                  * is not NULL since it's possible that we may have just
2394                  * added this vdev but not yet initialized its metaslabs.
2395                  */
2396                 if (tvd->vdev_islog && mg != NULL) {
2397                         /*
2398                          * Prevent any future allocations.
2399                          */
2400                         metaslab_group_passivate(mg);
2401                         (void) spa_vdev_state_exit(spa, vd, 0);
2402 
2403                         error = spa_offline_log(spa);
2404 
2405                         spa_vdev_state_enter(spa, SCL_ALLOC);
2406 
2407                         /*
2408                          * Check to see if the config has changed.
2409                          */
2410                         if (error || generation != spa->spa_config_generation) {
2411                                 metaslab_group_activate(mg);
2412                                 if (error)
2413                                         return (spa_vdev_state_exit(spa,
2414                                             vd, error));
2415                                 (void) spa_vdev_state_exit(spa, vd, 0);
2416                                 goto top;
2417                         }
2418                         ASSERT0(tvd->vdev_stat.vs_alloc);
2419                 }
2420 
2421                 /*
2422                  * Offline this device and reopen its top-level vdev.
2423                  * If the top-level vdev is a log device then just offline
2424                  * it. Otherwise, if this action results in the top-level
2425                  * vdev becoming unusable, undo it and fail the request.
2426                  */
2427                 vd->vdev_offline = B_TRUE;
2428                 vdev_reopen(tvd);
2429 
2430                 if (!tvd->vdev_islog && vd->vdev_aux == NULL &&
2431                     vdev_is_dead(tvd)) {
2432                         vd->vdev_offline = B_FALSE;
2433                         vdev_reopen(tvd);
2434                         return (spa_vdev_state_exit(spa, NULL, EBUSY));
2435                 }
2436 
2437                 /*
2438                  * Add the device back into the metaslab rotor so that
2439                  * once we online the device it's open for business.
2440                  */
2441                 if (tvd->vdev_islog && mg != NULL)
2442                         metaslab_group_activate(mg);
2443         }
2444 
2445         vd->vdev_tmpoffline = !!(flags & ZFS_OFFLINE_TEMPORARY);
2446 
2447         return (spa_vdev_state_exit(spa, vd, 0));
2448 }
2449 
2450 int
2451 vdev_offline(spa_t *spa, uint64_t guid, uint64_t flags)
2452 {
2453         int error;
2454 
2455         mutex_enter(&spa->spa_vdev_top_lock);
2456         error = vdev_offline_locked(spa, guid, flags);
2457         mutex_exit(&spa->spa_vdev_top_lock);
2458 
2459         return (error);
2460 }
2461 
2462 /*
2463  * Clear the error counts associated with this vdev.  Unlike vdev_online() and
2464  * vdev_offline(), we assume the spa config is locked.  We also clear all
2465  * children.  If 'vd' is NULL, then the user wants to clear all vdevs.
2466  */
2467 void
2468 vdev_clear(spa_t *spa, vdev_t *vd)
2469 {
2470         vdev_t *rvd = spa->spa_root_vdev;
2471 
2472         ASSERT(spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
2473 
2474         if (vd == NULL)
2475                 vd = rvd;
2476 
2477         vd->vdev_stat.vs_read_errors = 0;
2478         vd->vdev_stat.vs_write_errors = 0;
2479         vd->vdev_stat.vs_checksum_errors = 0;
2480 
2481         for (int c = 0; c < vd->vdev_children; c++)
2482                 vdev_clear(spa, vd->vdev_child[c]);
2483 
2484         /*
2485          * If we're in the FAULTED state or have experienced failed I/O, then
2486          * clear the persistent state and attempt to reopen the device.  We
2487          * also mark the vdev config dirty, so that the new faulted state is
2488          * written out to disk.
2489          */
2490         if (vd->vdev_faulted || vd->vdev_degraded ||
2491             !vdev_readable(vd) || !vdev_writeable(vd)) {
2492 
2493                 /*
2494                  * When reopening in reponse to a clear event, it may be due to
2495                  * a fmadm repair request.  In this case, if the device is
2496                  * still broken, we want to still post the ereport again.
2497                  */
2498                 vd->vdev_forcefault = B_TRUE;
2499 
2500                 vd->vdev_faulted = vd->vdev_degraded = 0ULL;
2501                 vd->vdev_cant_read = B_FALSE;
2502                 vd->vdev_cant_write = B_FALSE;
2503 
2504                 vdev_reopen(vd == rvd ? rvd : vd->vdev_top);
2505 
2506                 vd->vdev_forcefault = B_FALSE;
2507 
2508                 if (vd != rvd && vdev_writeable(vd->vdev_top))
2509                         vdev_state_dirty(vd->vdev_top);
2510 
2511                 if (vd->vdev_aux == NULL && !vdev_is_dead(vd))
2512                         spa_async_request(spa, SPA_ASYNC_RESILVER);
2513 
2514                 spa_event_notify(spa, vd, ESC_ZFS_VDEV_CLEAR);
2515         }
2516 
2517         /*
2518          * When clearing a FMA-diagnosed fault, we always want to
2519          * unspare the device, as we assume that the original spare was
2520          * done in response to the FMA fault.
2521          */
2522         if (!vdev_is_dead(vd) && vd->vdev_parent != NULL &&
2523             vd->vdev_parent->vdev_ops == &vdev_spare_ops &&
2524             vd->vdev_parent->vdev_child[0] == vd)
2525                 vd->vdev_unspare = B_TRUE;
2526 }
2527 
2528 boolean_t
2529 vdev_is_dead(vdev_t *vd)
2530 {
2531         /*
2532          * Holes and missing devices are always considered "dead".
2533          * This simplifies the code since we don't have to check for
2534          * these types of devices in the various code paths.
2535          * Instead we rely on the fact that we skip over dead devices
2536          * before issuing I/O to them.
2537          */
2538         return (vd->vdev_state < VDEV_STATE_DEGRADED || vd->vdev_ishole ||
2539             vd->vdev_ops == &vdev_missing_ops);
2540 }
2541 
2542 boolean_t
2543 vdev_readable(vdev_t *vd)
2544 {
2545         return (!vdev_is_dead(vd) && !vd->vdev_cant_read);
2546 }
2547 
2548 boolean_t
2549 vdev_writeable(vdev_t *vd)
2550 {
2551         return (!vdev_is_dead(vd) && !vd->vdev_cant_write);
2552 }
2553 
2554 boolean_t
2555 vdev_allocatable(vdev_t *vd)
2556 {
2557         uint64_t state = vd->vdev_state;
2558 
2559         /*
2560          * We currently allow allocations from vdevs which may be in the
2561          * process of reopening (i.e. VDEV_STATE_CLOSED). If the device
2562          * fails to reopen then we'll catch it later when we're holding
2563          * the proper locks.  Note that we have to get the vdev state
2564          * in a local variable because although it changes atomically,
2565          * we're asking two separate questions about it.
2566          */
2567         return (!(state < VDEV_STATE_DEGRADED && state != VDEV_STATE_CLOSED) &&
2568             !vd->vdev_cant_write && !vd->vdev_ishole);
2569 }
2570 
2571 boolean_t
2572 vdev_accessible(vdev_t *vd, zio_t *zio)
2573 {
2574         ASSERT(zio->io_vd == vd);
2575 
2576         if (vdev_is_dead(vd) || vd->vdev_remove_wanted)
2577                 return (B_FALSE);
2578 
2579         if (zio->io_type == ZIO_TYPE_READ)
2580                 return (!vd->vdev_cant_read);
2581 
2582         if (zio->io_type == ZIO_TYPE_WRITE)
2583                 return (!vd->vdev_cant_write);
2584 
2585         return (B_TRUE);
2586 }
2587 
2588 /*
2589  * Get statistics for the given vdev.
2590  */
2591 void
2592 vdev_get_stats(vdev_t *vd, vdev_stat_t *vs)
2593 {
2594         vdev_t *rvd = vd->vdev_spa->spa_root_vdev;
2595 
2596         mutex_enter(&vd->vdev_stat_lock);
2597         bcopy(&vd->vdev_stat, vs, sizeof (*vs));
2598         vs->vs_timestamp = gethrtime() - vs->vs_timestamp;
2599         vs->vs_state = vd->vdev_state;
2600         vs->vs_rsize = vdev_get_min_asize(vd);
2601         if (vd->vdev_ops->vdev_op_leaf)
2602                 vs->vs_rsize += VDEV_LABEL_START_SIZE + VDEV_LABEL_END_SIZE;
2603         vs->vs_esize = vd->vdev_max_asize - vd->vdev_asize;
2604         mutex_exit(&vd->vdev_stat_lock);
2605 
2606         /*
2607          * If we're getting stats on the root vdev, aggregate the I/O counts
2608          * over all top-level vdevs (i.e. the direct children of the root).
2609          */
2610         if (vd == rvd) {
2611                 for (int c = 0; c < rvd->vdev_children; c++) {
2612                         vdev_t *cvd = rvd->vdev_child[c];
2613                         vdev_stat_t *cvs = &cvd->vdev_stat;
2614 
2615                         mutex_enter(&vd->vdev_stat_lock);
2616                         for (int t = 0; t < ZIO_TYPES; t++) {
2617                                 vs->vs_ops[t] += cvs->vs_ops[t];
2618                                 vs->vs_bytes[t] += cvs->vs_bytes[t];
2619                         }
2620                         cvs->vs_scan_removing = cvd->vdev_removing;
2621                         mutex_exit(&vd->vdev_stat_lock);
2622                 }
2623         }
2624 }
2625 
2626 void
2627 vdev_clear_stats(vdev_t *vd)
2628 {
2629         mutex_enter(&vd->vdev_stat_lock);
2630         vd->vdev_stat.vs_space = 0;
2631         vd->vdev_stat.vs_dspace = 0;
2632         vd->vdev_stat.vs_alloc = 0;
2633         mutex_exit(&vd->vdev_stat_lock);
2634 }
2635 
2636 void
2637 vdev_scan_stat_init(vdev_t *vd)
2638 {
2639         vdev_stat_t *vs = &vd->vdev_stat;
2640 
2641         for (int c = 0; c < vd->vdev_children; c++)
2642                 vdev_scan_stat_init(vd->vdev_child[c]);
2643 
2644         mutex_enter(&vd->vdev_stat_lock);
2645         vs->vs_scan_processed = 0;
2646         mutex_exit(&vd->vdev_stat_lock);
2647 }
2648 
2649 void
2650 vdev_stat_update(zio_t *zio, uint64_t psize)
2651 {
2652         spa_t *spa = zio->io_spa;
2653         vdev_t *rvd = spa->spa_root_vdev;
2654         vdev_t *vd = zio->io_vd ? zio->io_vd : rvd;
2655         vdev_t *pvd;
2656         uint64_t txg = zio->io_txg;
2657         vdev_stat_t *vs = &vd->vdev_stat;
2658         zio_type_t type = zio->io_type;
2659         int flags = zio->io_flags;
2660 
2661         /*
2662          * If this i/o is a gang leader, it didn't do any actual work.
2663          */
2664         if (zio->io_gang_tree)
2665                 return;
2666 
2667         if (zio->io_error == 0) {
2668                 /*
2669                  * If this is a root i/o, don't count it -- we've already
2670                  * counted the top-level vdevs, and vdev_get_stats() will
2671                  * aggregate them when asked.  This reduces contention on
2672                  * the root vdev_stat_lock and implicitly handles blocks
2673                  * that compress away to holes, for which there is no i/o.
2674                  * (Holes never create vdev children, so all the counters
2675                  * remain zero, which is what we want.)
2676                  *
2677                  * Note: this only applies to successful i/o (io_error == 0)
2678                  * because unlike i/o counts, errors are not additive.
2679                  * When reading a ditto block, for example, failure of
2680                  * one top-level vdev does not imply a root-level error.
2681                  */
2682                 if (vd == rvd)
2683                         return;
2684 
2685                 ASSERT(vd == zio->io_vd);
2686 
2687                 if (flags & ZIO_FLAG_IO_BYPASS)
2688                         return;
2689 
2690                 mutex_enter(&vd->vdev_stat_lock);
2691 
2692                 if (flags & ZIO_FLAG_IO_REPAIR) {
2693                         if (flags & ZIO_FLAG_SCAN_THREAD) {
2694                                 dsl_scan_phys_t *scn_phys =
2695                                     &spa->spa_dsl_pool->dp_scan->scn_phys;
2696                                 uint64_t *processed = &scn_phys->scn_processed;
2697 
2698                                 /* XXX cleanup? */
2699                                 if (vd->vdev_ops->vdev_op_leaf)
2700                                         atomic_add_64(processed, psize);
2701                                 vs->vs_scan_processed += psize;
2702                         }
2703 
2704                         if (flags & ZIO_FLAG_SELF_HEAL)
2705                                 vs->vs_self_healed += psize;
2706                 }
2707 
2708                 vs->vs_ops[type]++;
2709                 vs->vs_bytes[type] += psize;
2710 
2711                 mutex_exit(&vd->vdev_stat_lock);
2712                 return;
2713         }
2714 
2715         if (flags & ZIO_FLAG_SPECULATIVE)
2716                 return;
2717 
2718         /*
2719          * If this is an I/O error that is going to be retried, then ignore the
2720          * error.  Otherwise, the user may interpret B_FAILFAST I/O errors as
2721          * hard errors, when in reality they can happen for any number of
2722          * innocuous reasons (bus resets, MPxIO link failure, etc).
2723          */
2724         if (zio->io_error == EIO &&
2725             !(zio->io_flags & ZIO_FLAG_IO_RETRY))
2726                 return;
2727 
2728         /*
2729          * Intent logs writes won't propagate their error to the root
2730          * I/O so don't mark these types of failures as pool-level
2731          * errors.
2732          */
2733         if (zio->io_vd == NULL && (zio->io_flags & ZIO_FLAG_DONT_PROPAGATE))
2734                 return;
2735 
2736         mutex_enter(&vd->vdev_stat_lock);
2737         if (type == ZIO_TYPE_READ && !vdev_is_dead(vd)) {
2738                 if (zio->io_error == ECKSUM)
2739                         vs->vs_checksum_errors++;
2740                 else
2741                         vs->vs_read_errors++;
2742         }
2743         if (type == ZIO_TYPE_WRITE && !vdev_is_dead(vd))
2744                 vs->vs_write_errors++;
2745         mutex_exit(&vd->vdev_stat_lock);
2746 
2747         if (type == ZIO_TYPE_WRITE && txg != 0 &&
2748             (!(flags & ZIO_FLAG_IO_REPAIR) ||
2749             (flags & ZIO_FLAG_SCAN_THREAD) ||
2750             spa->spa_claiming)) {
2751                 /*
2752                  * This is either a normal write (not a repair), or it's
2753                  * a repair induced by the scrub thread, or it's a repair
2754                  * made by zil_claim() during spa_load() in the first txg.
2755                  * In the normal case, we commit the DTL change in the same
2756                  * txg as the block was born.  In the scrub-induced repair
2757                  * case, we know that scrubs run in first-pass syncing context,
2758                  * so we commit the DTL change in spa_syncing_txg(spa).
2759                  * In the zil_claim() case, we commit in spa_first_txg(spa).
2760                  *
2761                  * We currently do not make DTL entries for failed spontaneous
2762                  * self-healing writes triggered by normal (non-scrubbing)
2763                  * reads, because we have no transactional context in which to
2764                  * do so -- and it's not clear that it'd be desirable anyway.
2765                  */
2766                 if (vd->vdev_ops->vdev_op_leaf) {
2767                         uint64_t commit_txg = txg;
2768                         if (flags & ZIO_FLAG_SCAN_THREAD) {
2769                                 ASSERT(flags & ZIO_FLAG_IO_REPAIR);
2770                                 ASSERT(spa_sync_pass(spa) == 1);
2771                                 vdev_dtl_dirty(vd, DTL_SCRUB, txg, 1);
2772                                 commit_txg = spa_syncing_txg(spa);
2773                         } else if (spa->spa_claiming) {
2774                                 ASSERT(flags & ZIO_FLAG_IO_REPAIR);
2775                                 commit_txg = spa_first_txg(spa);
2776                         }
2777                         ASSERT(commit_txg >= spa_syncing_txg(spa));
2778                         if (vdev_dtl_contains(vd, DTL_MISSING, txg, 1))
2779                                 return;
2780                         for (pvd = vd; pvd != rvd; pvd = pvd->vdev_parent)
2781                                 vdev_dtl_dirty(pvd, DTL_PARTIAL, txg, 1);
2782                         vdev_dirty(vd->vdev_top, VDD_DTL, vd, commit_txg);
2783                 }
2784                 if (vd != rvd)
2785                         vdev_dtl_dirty(vd, DTL_MISSING, txg, 1);
2786         }
2787 }
2788 
2789 /*
2790  * Update the in-core space usage stats for this vdev, its metaslab class,
2791  * and the root vdev.
2792  */
2793 void
2794 vdev_space_update(vdev_t *vd, int64_t alloc_delta, int64_t defer_delta,
2795     int64_t space_delta)
2796 {
2797         int64_t dspace_delta = space_delta;
2798         spa_t *spa = vd->vdev_spa;
2799         vdev_t *rvd = spa->spa_root_vdev;
2800         metaslab_group_t *mg = vd->vdev_mg;
2801         metaslab_class_t *mc = mg ? mg->mg_class : NULL;
2802 
2803         ASSERT(vd == vd->vdev_top);
2804 
2805         /*
2806          * Apply the inverse of the psize-to-asize (ie. RAID-Z) space-expansion
2807          * factor.  We must calculate this here and not at the root vdev
2808          * because the root vdev's psize-to-asize is simply the max of its
2809          * childrens', thus not accurate enough for us.
2810          */
2811         ASSERT((dspace_delta & (SPA_MINBLOCKSIZE-1)) == 0);
2812         ASSERT(vd->vdev_deflate_ratio != 0 || vd->vdev_isl2cache);
2813         dspace_delta = (dspace_delta >> SPA_MINBLOCKSHIFT) *
2814             vd->vdev_deflate_ratio;
2815 
2816         mutex_enter(&vd->vdev_stat_lock);
2817         vd->vdev_stat.vs_alloc += alloc_delta;
2818         vd->vdev_stat.vs_space += space_delta;
2819         vd->vdev_stat.vs_dspace += dspace_delta;
2820         mutex_exit(&vd->vdev_stat_lock);
2821 
2822         if (mc == spa_normal_class(spa)) {
2823                 mutex_enter(&rvd->vdev_stat_lock);
2824                 rvd->vdev_stat.vs_alloc += alloc_delta;
2825                 rvd->vdev_stat.vs_space += space_delta;
2826                 rvd->vdev_stat.vs_dspace += dspace_delta;
2827                 mutex_exit(&rvd->vdev_stat_lock);
2828         }
2829 
2830         if (mc != NULL) {
2831                 ASSERT(rvd == vd->vdev_parent);
2832                 ASSERT(vd->vdev_ms_count != 0);
2833 
2834                 metaslab_class_space_update(mc,
2835                     alloc_delta, defer_delta, space_delta, dspace_delta);
2836         }
2837 }
2838 
2839 /*
2840  * Mark a top-level vdev's config as dirty, placing it on the dirty list
2841  * so that it will be written out next time the vdev configuration is synced.
2842  * If the root vdev is specified (vdev_top == NULL), dirty all top-level vdevs.
2843  */
2844 void
2845 vdev_config_dirty(vdev_t *vd)
2846 {
2847         spa_t *spa = vd->vdev_spa;
2848         vdev_t *rvd = spa->spa_root_vdev;
2849         int c;
2850 
2851         ASSERT(spa_writeable(spa));
2852 
2853         /*
2854          * If this is an aux vdev (as with l2cache and spare devices), then we
2855          * update the vdev config manually and set the sync flag.
2856          */
2857         if (vd->vdev_aux != NULL) {
2858                 spa_aux_vdev_t *sav = vd->vdev_aux;
2859                 nvlist_t **aux;
2860                 uint_t naux;
2861 
2862                 for (c = 0; c < sav->sav_count; c++) {
2863                         if (sav->sav_vdevs[c] == vd)
2864                                 break;
2865                 }
2866 
2867                 if (c == sav->sav_count) {
2868                         /*
2869                          * We're being removed.  There's nothing more to do.
2870                          */
2871                         ASSERT(sav->sav_sync == B_TRUE);
2872                         return;
2873                 }
2874 
2875                 sav->sav_sync = B_TRUE;
2876 
2877                 if (nvlist_lookup_nvlist_array(sav->sav_config,
2878                     ZPOOL_CONFIG_L2CACHE, &aux, &naux) != 0) {
2879                         VERIFY(nvlist_lookup_nvlist_array(sav->sav_config,
2880                             ZPOOL_CONFIG_SPARES, &aux, &naux) == 0);
2881                 }
2882 
2883                 ASSERT(c < naux);
2884 
2885                 /*
2886                  * Setting the nvlist in the middle if the array is a little
2887                  * sketchy, but it will work.
2888                  */
2889                 nvlist_free(aux[c]);
2890                 aux[c] = vdev_config_generate(spa, vd, B_TRUE, 0);
2891 
2892                 return;
2893         }
2894 
2895         /*
2896          * The dirty list is protected by the SCL_CONFIG lock.  The caller
2897          * must either hold SCL_CONFIG as writer, or must be the sync thread
2898          * (which holds SCL_CONFIG as reader).  There's only one sync thread,
2899          * so this is sufficient to ensure mutual exclusion.
2900          */
2901         ASSERT(spa_config_held(spa, SCL_CONFIG, RW_WRITER) ||
2902             (dsl_pool_sync_context(spa_get_dsl(spa)) &&
2903             spa_config_held(spa, SCL_CONFIG, RW_READER)));
2904 
2905         if (vd == rvd) {
2906                 for (c = 0; c < rvd->vdev_children; c++)
2907                         vdev_config_dirty(rvd->vdev_child[c]);
2908         } else {
2909                 ASSERT(vd == vd->vdev_top);
2910 
2911                 if (!list_link_active(&vd->vdev_config_dirty_node) &&
2912                     !vd->vdev_ishole)
2913                         list_insert_head(&spa->spa_config_dirty_list, vd);
2914         }
2915 }
2916 
2917 void
2918 vdev_config_clean(vdev_t *vd)
2919 {
2920         spa_t *spa = vd->vdev_spa;
2921 
2922         ASSERT(spa_config_held(spa, SCL_CONFIG, RW_WRITER) ||
2923             (dsl_pool_sync_context(spa_get_dsl(spa)) &&
2924             spa_config_held(spa, SCL_CONFIG, RW_READER)));
2925 
2926         ASSERT(list_link_active(&vd->vdev_config_dirty_node));
2927         list_remove(&spa->spa_config_dirty_list, vd);
2928 }
2929 
2930 /*
2931  * Mark a top-level vdev's state as dirty, so that the next pass of
2932  * spa_sync() can convert this into vdev_config_dirty().  We distinguish
2933  * the state changes from larger config changes because they require
2934  * much less locking, and are often needed for administrative actions.
2935  */
2936 void
2937 vdev_state_dirty(vdev_t *vd)
2938 {
2939         spa_t *spa = vd->vdev_spa;
2940 
2941         ASSERT(spa_writeable(spa));
2942         ASSERT(vd == vd->vdev_top);
2943 
2944         /*
2945          * The state list is protected by the SCL_STATE lock.  The caller
2946          * must either hold SCL_STATE as writer, or must be the sync thread
2947          * (which holds SCL_STATE as reader).  There's only one sync thread,
2948          * so this is sufficient to ensure mutual exclusion.
2949          */
2950         ASSERT(spa_config_held(spa, SCL_STATE, RW_WRITER) ||
2951             (dsl_pool_sync_context(spa_get_dsl(spa)) &&
2952             spa_config_held(spa, SCL_STATE, RW_READER)));
2953 
2954         if (!list_link_active(&vd->vdev_state_dirty_node) && !vd->vdev_ishole)
2955                 list_insert_head(&spa->spa_state_dirty_list, vd);
2956 }
2957 
2958 void
2959 vdev_state_clean(vdev_t *vd)
2960 {
2961         spa_t *spa = vd->vdev_spa;
2962 
2963         ASSERT(spa_config_held(spa, SCL_STATE, RW_WRITER) ||
2964             (dsl_pool_sync_context(spa_get_dsl(spa)) &&
2965             spa_config_held(spa, SCL_STATE, RW_READER)));
2966 
2967         ASSERT(list_link_active(&vd->vdev_state_dirty_node));
2968         list_remove(&spa->spa_state_dirty_list, vd);
2969 }
2970 
2971 /*
2972  * Propagate vdev state up from children to parent.
2973  */
2974 void
2975 vdev_propagate_state(vdev_t *vd)
2976 {
2977         spa_t *spa = vd->vdev_spa;
2978         vdev_t *rvd = spa->spa_root_vdev;
2979         int degraded = 0, faulted = 0;
2980         int corrupted = 0;
2981         vdev_t *child;
2982 
2983         if (vd->vdev_children > 0) {
2984                 for (int c = 0; c < vd->vdev_children; c++) {
2985                         child = vd->vdev_child[c];
2986 
2987                         /*
2988                          * Don't factor holes into the decision.
2989                          */
2990                         if (child->vdev_ishole)
2991                                 continue;
2992 
2993                         if (!vdev_readable(child) ||
2994                             (!vdev_writeable(child) && spa_writeable(spa))) {
2995                                 /*
2996                                  * Root special: if there is a top-level log
2997                                  * device, treat the root vdev as if it were
2998                                  * degraded.
2999                                  */
3000                                 if (child->vdev_islog && vd == rvd)
3001                                         degraded++;
3002                                 else
3003                                         faulted++;
3004                         } else if (child->vdev_state <= VDEV_STATE_DEGRADED) {
3005                                 degraded++;
3006                         }
3007 
3008                         if (child->vdev_stat.vs_aux == VDEV_AUX_CORRUPT_DATA)
3009                                 corrupted++;
3010                 }
3011 
3012                 vd->vdev_ops->vdev_op_state_change(vd, faulted, degraded);
3013 
3014                 /*
3015                  * Root special: if there is a top-level vdev that cannot be
3016                  * opened due to corrupted metadata, then propagate the root
3017                  * vdev's aux state as 'corrupt' rather than 'insufficient
3018                  * replicas'.
3019                  */
3020                 if (corrupted && vd == rvd &&
3021                     rvd->vdev_state == VDEV_STATE_CANT_OPEN)
3022                         vdev_set_state(rvd, B_FALSE, VDEV_STATE_CANT_OPEN,
3023                             VDEV_AUX_CORRUPT_DATA);
3024         }
3025 
3026         if (vd->vdev_parent)
3027                 vdev_propagate_state(vd->vdev_parent);
3028 }
3029 
3030 /*
3031  * Set a vdev's state.  If this is during an open, we don't update the parent
3032  * state, because we're in the process of opening children depth-first.
3033  * Otherwise, we propagate the change to the parent.
3034  *
3035  * If this routine places a device in a faulted state, an appropriate ereport is
3036  * generated.
3037  */
3038 void
3039 vdev_set_state(vdev_t *vd, boolean_t isopen, vdev_state_t state, vdev_aux_t aux)
3040 {
3041         uint64_t save_state;
3042         spa_t *spa = vd->vdev_spa;
3043 
3044         if (state == vd->vdev_state) {
3045                 vd->vdev_stat.vs_aux = aux;
3046                 return;
3047         }
3048 
3049         save_state = vd->vdev_state;
3050 
3051         vd->vdev_state = state;
3052         vd->vdev_stat.vs_aux = aux;
3053 
3054         /*
3055          * If we are setting the vdev state to anything but an open state, then
3056          * always close the underlying device unless the device has requested
3057          * a delayed close (i.e. we're about to remove or fault the device).
3058          * Otherwise, we keep accessible but invalid devices open forever.
3059          * We don't call vdev_close() itself, because that implies some extra
3060          * checks (offline, etc) that we don't want here.  This is limited to
3061          * leaf devices, because otherwise closing the device will affect other
3062          * children.
3063          */
3064         if (!vd->vdev_delayed_close && vdev_is_dead(vd) &&
3065             vd->vdev_ops->vdev_op_leaf)
3066                 vd->vdev_ops->vdev_op_close(vd);
3067 
3068         /*
3069          * If we have brought this vdev back into service, we need
3070          * to notify fmd so that it can gracefully repair any outstanding
3071          * cases due to a missing device.  We do this in all cases, even those
3072          * that probably don't correlate to a repaired fault.  This is sure to
3073          * catch all cases, and we let the zfs-retire agent sort it out.  If
3074          * this is a transient state it's OK, as the retire agent will
3075          * double-check the state of the vdev before repairing it.
3076          */
3077         if (state == VDEV_STATE_HEALTHY && vd->vdev_ops->vdev_op_leaf &&
3078             vd->vdev_prevstate != state)
3079                 zfs_post_state_change(spa, vd);
3080 
3081         if (vd->vdev_removed &&
3082             state == VDEV_STATE_CANT_OPEN &&
3083             (aux == VDEV_AUX_OPEN_FAILED || vd->vdev_checkremove)) {
3084                 /*
3085                  * If the previous state is set to VDEV_STATE_REMOVED, then this
3086                  * device was previously marked removed and someone attempted to
3087                  * reopen it.  If this failed due to a nonexistent device, then
3088                  * keep the device in the REMOVED state.  We also let this be if
3089                  * it is one of our special test online cases, which is only
3090                  * attempting to online the device and shouldn't generate an FMA
3091                  * fault.
3092                  */
3093                 vd->vdev_state = VDEV_STATE_REMOVED;
3094                 vd->vdev_stat.vs_aux = VDEV_AUX_NONE;
3095         } else if (state == VDEV_STATE_REMOVED) {
3096                 vd->vdev_removed = B_TRUE;
3097         } else if (state == VDEV_STATE_CANT_OPEN) {
3098                 /*
3099                  * If we fail to open a vdev during an import or recovery, we
3100                  * mark it as "not available", which signifies that it was
3101                  * never there to begin with.  Failure to open such a device
3102                  * is not considered an error.
3103                  */
3104                 if ((spa_load_state(spa) == SPA_LOAD_IMPORT ||
3105                     spa_load_state(spa) == SPA_LOAD_RECOVER) &&
3106                     vd->vdev_ops->vdev_op_leaf)
3107                         vd->vdev_not_present = 1;
3108 
3109                 /*
3110                  * Post the appropriate ereport.  If the 'prevstate' field is
3111                  * set to something other than VDEV_STATE_UNKNOWN, it indicates
3112                  * that this is part of a vdev_reopen().  In this case, we don't
3113                  * want to post the ereport if the device was already in the
3114                  * CANT_OPEN state beforehand.
3115                  *
3116                  * If the 'checkremove' flag is set, then this is an attempt to
3117                  * online the device in response to an insertion event.  If we
3118                  * hit this case, then we have detected an insertion event for a
3119                  * faulted or offline device that wasn't in the removed state.
3120                  * In this scenario, we don't post an ereport because we are
3121                  * about to replace the device, or attempt an online with
3122                  * vdev_forcefault, which will generate the fault for us.
3123                  */
3124                 if ((vd->vdev_prevstate != state || vd->vdev_forcefault) &&
3125                     !vd->vdev_not_present && !vd->vdev_checkremove &&
3126                     vd != spa->spa_root_vdev) {
3127                         const char *class;
3128 
3129                         switch (aux) {
3130                         case VDEV_AUX_OPEN_FAILED:
3131                                 class = FM_EREPORT_ZFS_DEVICE_OPEN_FAILED;
3132                                 break;
3133                         case VDEV_AUX_CORRUPT_DATA:
3134                                 class = FM_EREPORT_ZFS_DEVICE_CORRUPT_DATA;
3135                                 break;
3136                         case VDEV_AUX_NO_REPLICAS:
3137                                 class = FM_EREPORT_ZFS_DEVICE_NO_REPLICAS;
3138                                 break;
3139                         case VDEV_AUX_BAD_GUID_SUM:
3140                                 class = FM_EREPORT_ZFS_DEVICE_BAD_GUID_SUM;
3141                                 break;
3142                         case VDEV_AUX_TOO_SMALL:
3143                                 class = FM_EREPORT_ZFS_DEVICE_TOO_SMALL;
3144                                 break;
3145                         case VDEV_AUX_BAD_LABEL:
3146                                 class = FM_EREPORT_ZFS_DEVICE_BAD_LABEL;
3147                                 break;
3148                         default:
3149                                 class = FM_EREPORT_ZFS_DEVICE_UNKNOWN;
3150                         }
3151 
3152                         zfs_ereport_post(class, spa, vd, NULL, save_state, 0);
3153                 }
3154 
3155                 /* Erase any notion of persistent removed state */
3156                 vd->vdev_removed = B_FALSE;
3157         } else {
3158                 vd->vdev_removed = B_FALSE;
3159         }
3160 
3161         if (!isopen && vd->vdev_parent)
3162                 vdev_propagate_state(vd->vdev_parent);
3163 }
3164 
3165 /*
3166  * Check the vdev configuration to ensure that it's capable of supporting
3167  * a root pool. Currently, we do not support RAID-Z or partial configuration.
3168  * In addition, only a single top-level vdev is allowed and none of the leaves
3169  * can be wholedisks.
3170  */
3171 boolean_t
3172 vdev_is_bootable(vdev_t *vd)
3173 {
3174         if (!vd->vdev_ops->vdev_op_leaf) {
3175                 char *vdev_type = vd->vdev_ops->vdev_op_type;
3176 
3177                 if (strcmp(vdev_type, VDEV_TYPE_ROOT) == 0 &&
3178                     vd->vdev_children > 1) {
3179                         return (B_FALSE);
3180                 } else if (strcmp(vdev_type, VDEV_TYPE_RAIDZ) == 0 ||
3181                     strcmp(vdev_type, VDEV_TYPE_MISSING) == 0) {
3182                         return (B_FALSE);
3183                 }
3184         } else if (vd->vdev_wholedisk == 1) {
3185                 return (B_FALSE);
3186         }
3187 
3188         for (int c = 0; c < vd->vdev_children; c++) {
3189                 if (!vdev_is_bootable(vd->vdev_child[c]))
3190                         return (B_FALSE);
3191         }
3192         return (B_TRUE);
3193 }
3194 
3195 /*
3196  * Load the state from the original vdev tree (ovd) which
3197  * we've retrieved from the MOS config object. If the original
3198  * vdev was offline or faulted then we transfer that state to the
3199  * device in the current vdev tree (nvd).
3200  */
3201 void
3202 vdev_load_log_state(vdev_t *nvd, vdev_t *ovd)
3203 {
3204         spa_t *spa = nvd->vdev_spa;
3205 
3206         ASSERT(nvd->vdev_top->vdev_islog);
3207         ASSERT(spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
3208         ASSERT3U(nvd->vdev_guid, ==, ovd->vdev_guid);
3209 
3210         for (int c = 0; c < nvd->vdev_children; c++)
3211                 vdev_load_log_state(nvd->vdev_child[c], ovd->vdev_child[c]);
3212 
3213         if (nvd->vdev_ops->vdev_op_leaf) {
3214                 /*
3215                  * Restore the persistent vdev state
3216                  */
3217                 nvd->vdev_offline = ovd->vdev_offline;
3218                 nvd->vdev_faulted = ovd->vdev_faulted;
3219                 nvd->vdev_degraded = ovd->vdev_degraded;
3220                 nvd->vdev_removed = ovd->vdev_removed;
3221         }
3222 }
3223 
3224 /*
3225  * Determine if a log device has valid content.  If the vdev was
3226  * removed or faulted in the MOS config then we know that
3227  * the content on the log device has already been written to the pool.
3228  */
3229 boolean_t
3230 vdev_log_state_valid(vdev_t *vd)
3231 {
3232         if (vd->vdev_ops->vdev_op_leaf && !vd->vdev_faulted &&
3233             !vd->vdev_removed)
3234                 return (B_TRUE);
3235 
3236         for (int c = 0; c < vd->vdev_children; c++)
3237                 if (vdev_log_state_valid(vd->vdev_child[c]))
3238                         return (B_TRUE);
3239 
3240         return (B_FALSE);
3241 }
3242 
3243 /*
3244  * Expand a vdev if possible.
3245  */
3246 void
3247 vdev_expand(vdev_t *vd, uint64_t txg)
3248 {
3249         ASSERT(vd->vdev_top == vd);
3250         ASSERT(spa_config_held(vd->vdev_spa, SCL_ALL, RW_WRITER) == SCL_ALL);
3251 
3252         if ((vd->vdev_asize >> vd->vdev_ms_shift) > vd->vdev_ms_count) {
3253                 VERIFY(vdev_metaslab_init(vd, txg) == 0);
3254                 vdev_config_dirty(vd);
3255         }
3256 }
3257 
3258 /*
3259  * Split a vdev.
3260  */
3261 void
3262 vdev_split(vdev_t *vd)
3263 {
3264         vdev_t *cvd, *pvd = vd->vdev_parent;
3265 
3266         vdev_remove_child(pvd, vd);
3267         vdev_compact_children(pvd);
3268 
3269         cvd = pvd->vdev_child[0];
3270         if (pvd->vdev_children == 1) {
3271                 vdev_remove_parent(cvd);
3272                 cvd->vdev_splitting = B_TRUE;
3273         }
3274         vdev_propagate_state(cvd);
3275 }
3276 
3277 void
3278 vdev_deadman(vdev_t *vd)
3279 {
3280         for (int c = 0; c < vd->vdev_children; c++) {
3281                 vdev_t *cvd = vd->vdev_child[c];
3282 
3283                 vdev_deadman(cvd);
3284         }
3285 
3286         if (vd->vdev_ops->vdev_op_leaf) {
3287                 vdev_queue_t *vq = &vd->vdev_queue;
3288 
3289                 mutex_enter(&vq->vq_lock);
3290                 if (avl_numnodes(&vq->vq_active_tree) > 0) {
3291                         spa_t *spa = vd->vdev_spa;
3292                         zio_t *fio;
3293                         uint64_t delta;
3294 
3295                         /*
3296                          * Look at the head of all the pending queues,
3297                          * if any I/O has been outstanding for longer than
3298                          * the spa_deadman_synctime we panic the system.
3299                          */
3300                         fio = avl_first(&vq->vq_active_tree);
3301                         delta = gethrtime() - fio->io_timestamp;
3302                         if (delta > spa_deadman_synctime(spa)) {
3303                                 zfs_dbgmsg("SLOW IO: zio timestamp %lluns, "
3304                                     "delta %lluns, last io %lluns",
3305                                     fio->io_timestamp, delta,
3306                                     vq->vq_io_complete_ts);
3307                                 fm_panic("I/O to pool '%s' appears to be "
3308                                     "hung.", spa_name(spa));
3309                         }
3310                 }
3311                 mutex_exit(&vq->vq_lock);
3312         }
3313 }