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