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 (c) 2011, 2014 by Delphix. All rights reserved.
  25  * Copyright 2015 Nexenta Systems, Inc.  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  * When a vdev is added, it will be divided into approximately (but no
  69  * more than) this number of metaslabs.
  70  */
  71 int metaslabs_per_vdev = 200;
  72 
  73 /*
  74  * Given a vdev type, return the appropriate ops vector.
  75  */
  76 static vdev_ops_t *
  77 vdev_getops(const char *type)
  78 {
  79         vdev_ops_t *ops, **opspp;
  80 
  81         for (opspp = vdev_ops_table; (ops = *opspp) != NULL; opspp++)
  82                 if (strcmp(ops->vdev_op_type, type) == 0)
  83                         break;
  84 
  85         return (ops);
  86 }
  87 
  88 /*
  89  * Default asize function: return the MAX of psize with the asize of
  90  * all children.  This is what's used by anything other than RAID-Z.
  91  */
  92 uint64_t
  93 vdev_default_asize(vdev_t *vd, uint64_t psize)
  94 {
  95         uint64_t asize = P2ROUNDUP(psize, 1ULL << vd->vdev_top->vdev_ashift);
  96         uint64_t csize;
  97 
  98         for (int c = 0; c < vd->vdev_children; c++) {
  99                 csize = vdev_psize_to_asize(vd->vdev_child[c], psize);
 100                 asize = MAX(asize, csize);
 101         }
 102 
 103         return (asize);
 104 }
 105 
 106 /*
 107  * Get the minimum allocatable size. We define the allocatable size as
 108  * the vdev's asize rounded to the nearest metaslab. This allows us to
 109  * replace or attach devices which don't have the same physical size but
 110  * can still satisfy the same number of allocations.
 111  */
 112 uint64_t
 113 vdev_get_min_asize(vdev_t *vd)
 114 {
 115         vdev_t *pvd = vd->vdev_parent;
 116 
 117         /*
 118          * If our parent is NULL (inactive spare or cache) or is the root,
 119          * just return our own asize.
 120          */
 121         if (pvd == NULL)
 122                 return (vd->vdev_asize);
 123 
 124         /*
 125          * The top-level vdev just returns the allocatable size rounded
 126          * to the nearest metaslab.
 127          */
 128         if (vd == vd->vdev_top)
 129                 return (P2ALIGN(vd->vdev_asize, 1ULL << vd->vdev_ms_shift));
 130 
 131         /*
 132          * The allocatable space for a raidz vdev is N * sizeof(smallest child),
 133          * so each child must provide at least 1/Nth of its asize.
 134          */
 135         if (pvd->vdev_ops == &vdev_raidz_ops)
 136                 return (pvd->vdev_min_asize / pvd->vdev_children);
 137 
 138         return (pvd->vdev_min_asize);
 139 }
 140 
 141 void
 142 vdev_set_min_asize(vdev_t *vd)
 143 {
 144         vd->vdev_min_asize = vdev_get_min_asize(vd);
 145 
 146         for (int c = 0; c < vd->vdev_children; c++)
 147                 vdev_set_min_asize(vd->vdev_child[c]);
 148 }
 149 
 150 vdev_t *
 151 vdev_lookup_top(spa_t *spa, uint64_t vdev)
 152 {
 153         vdev_t *rvd = spa->spa_root_vdev;
 154 
 155         ASSERT(spa_config_held(spa, SCL_ALL, RW_READER) != 0);
 156 
 157         if (vdev < rvd->vdev_children) {
 158                 ASSERT(rvd->vdev_child[vdev] != NULL);
 159                 return (rvd->vdev_child[vdev]);
 160         }
 161 
 162         return (NULL);
 163 }
 164 
 165 vdev_t *
 166 vdev_lookup_by_guid(vdev_t *vd, uint64_t guid)
 167 {
 168         vdev_t *mvd;
 169 
 170         if (vd->vdev_guid == guid)
 171                 return (vd);
 172 
 173         for (int c = 0; c < vd->vdev_children; c++)
 174                 if ((mvd = vdev_lookup_by_guid(vd->vdev_child[c], guid)) !=
 175                     NULL)
 176                         return (mvd);
 177 
 178         return (NULL);
 179 }
 180 
 181 static int
 182 vdev_count_leaves_impl(vdev_t *vd)
 183 {
 184         int n = 0;
 185 
 186         if (vd->vdev_ops->vdev_op_leaf)
 187                 return (1);
 188 
 189         for (int c = 0; c < vd->vdev_children; c++)
 190                 n += vdev_count_leaves_impl(vd->vdev_child[c]);
 191 
 192         return (n);
 193 }
 194 
 195 int
 196 vdev_count_leaves(spa_t *spa)
 197 {
 198         return (vdev_count_leaves_impl(spa->spa_root_vdev));
 199 }
 200 
 201 void
 202 vdev_add_child(vdev_t *pvd, vdev_t *cvd)
 203 {
 204         size_t oldsize, newsize;
 205         uint64_t id = cvd->vdev_id;
 206         vdev_t **newchild;
 207 
 208         ASSERT(spa_config_held(cvd->vdev_spa, SCL_ALL, RW_WRITER) == SCL_ALL);
 209         ASSERT(cvd->vdev_parent == NULL);
 210 
 211         cvd->vdev_parent = pvd;
 212 
 213         if (pvd == NULL)
 214                 return;
 215 
 216         ASSERT(id >= pvd->vdev_children || pvd->vdev_child[id] == NULL);
 217 
 218         oldsize = pvd->vdev_children * sizeof (vdev_t *);
 219         pvd->vdev_children = MAX(pvd->vdev_children, id + 1);
 220         newsize = pvd->vdev_children * sizeof (vdev_t *);
 221 
 222         newchild = kmem_zalloc(newsize, KM_SLEEP);
 223         if (pvd->vdev_child != NULL) {
 224                 bcopy(pvd->vdev_child, newchild, oldsize);
 225                 kmem_free(pvd->vdev_child, oldsize);
 226         }
 227 
 228         pvd->vdev_child = newchild;
 229         pvd->vdev_child[id] = cvd;
 230 
 231         cvd->vdev_top = (pvd->vdev_top ? pvd->vdev_top: cvd);
 232         ASSERT(cvd->vdev_top->vdev_parent->vdev_parent == NULL);
 233 
 234         /*
 235          * Walk up all ancestors to update guid sum.
 236          */
 237         for (; pvd != NULL; pvd = pvd->vdev_parent)
 238                 pvd->vdev_guid_sum += cvd->vdev_guid_sum;
 239 }
 240 
 241 void
 242 vdev_remove_child(vdev_t *pvd, vdev_t *cvd)
 243 {
 244         int c;
 245         uint_t id = cvd->vdev_id;
 246 
 247         ASSERT(cvd->vdev_parent == pvd);
 248 
 249         if (pvd == NULL)
 250                 return;
 251 
 252         ASSERT(id < pvd->vdev_children);
 253         ASSERT(pvd->vdev_child[id] == cvd);
 254 
 255         pvd->vdev_child[id] = NULL;
 256         cvd->vdev_parent = NULL;
 257 
 258         for (c = 0; c < pvd->vdev_children; c++)
 259                 if (pvd->vdev_child[c])
 260                         break;
 261 
 262         if (c == pvd->vdev_children) {
 263                 kmem_free(pvd->vdev_child, c * sizeof (vdev_t *));
 264                 pvd->vdev_child = NULL;
 265                 pvd->vdev_children = 0;
 266         }
 267 
 268         /*
 269          * Walk up all ancestors to update guid sum.
 270          */
 271         for (; pvd != NULL; pvd = pvd->vdev_parent)
 272                 pvd->vdev_guid_sum -= cvd->vdev_guid_sum;
 273 }
 274 
 275 /*
 276  * Remove any holes in the child array.
 277  */
 278 void
 279 vdev_compact_children(vdev_t *pvd)
 280 {
 281         vdev_t **newchild, *cvd;
 282         int oldc = pvd->vdev_children;
 283         int newc;
 284 
 285         ASSERT(spa_config_held(pvd->vdev_spa, SCL_ALL, RW_WRITER) == SCL_ALL);
 286 
 287         for (int c = newc = 0; c < oldc; c++)
 288                 if (pvd->vdev_child[c])
 289                         newc++;
 290 
 291         newchild = kmem_alloc(newc * sizeof (vdev_t *), KM_SLEEP);
 292 
 293         for (int c = newc = 0; c < oldc; c++) {
 294                 if ((cvd = pvd->vdev_child[c]) != NULL) {
 295                         newchild[newc] = cvd;
 296                         cvd->vdev_id = newc++;
 297                 }
 298         }
 299 
 300         kmem_free(pvd->vdev_child, oldc * sizeof (vdev_t *));
 301         pvd->vdev_child = newchild;
 302         pvd->vdev_children = newc;
 303 }
 304 
 305 /*
 306  * Allocate and minimally initialize a vdev_t.
 307  */
 308 vdev_t *
 309 vdev_alloc_common(spa_t *spa, uint_t id, uint64_t guid, vdev_ops_t *ops)
 310 {
 311         vdev_t *vd;
 312 
 313         vd = kmem_zalloc(sizeof (vdev_t), KM_SLEEP);
 314 
 315         if (spa->spa_root_vdev == NULL) {
 316                 ASSERT(ops == &vdev_root_ops);
 317                 spa->spa_root_vdev = vd;
 318                 spa->spa_load_guid = spa_generate_guid(NULL);
 319         }
 320 
 321         if (guid == 0 && ops != &vdev_hole_ops) {
 322                 if (spa->spa_root_vdev == vd) {
 323                         /*
 324                          * The root vdev's guid will also be the pool guid,
 325                          * which must be unique among all pools.
 326                          */
 327                         guid = spa_generate_guid(NULL);
 328                 } else {
 329                         /*
 330                          * Any other vdev's guid must be unique within the pool.
 331                          */
 332                         guid = spa_generate_guid(spa);
 333                 }
 334                 ASSERT(!spa_guid_exists(spa_guid(spa), guid));
 335         }
 336 
 337         vd->vdev_spa = spa;
 338         vd->vdev_id = id;
 339         vd->vdev_guid = guid;
 340         vd->vdev_guid_sum = guid;
 341         vd->vdev_ops = ops;
 342         vd->vdev_state = VDEV_STATE_CLOSED;
 343         vd->vdev_ishole = (ops == &vdev_hole_ops);
 344 
 345         mutex_init(&vd->vdev_dtl_lock, NULL, MUTEX_DEFAULT, NULL);
 346         mutex_init(&vd->vdev_stat_lock, NULL, MUTEX_DEFAULT, NULL);
 347         mutex_init(&vd->vdev_probe_lock, NULL, MUTEX_DEFAULT, NULL);
 348         for (int t = 0; t < DTL_TYPES; t++) {
 349                 vd->vdev_dtl[t] = range_tree_create(NULL, NULL,
 350                     &vd->vdev_dtl_lock);
 351         }
 352         txg_list_create(&vd->vdev_ms_list,
 353             offsetof(struct metaslab, ms_txg_node));
 354         txg_list_create(&vd->vdev_dtl_list,
 355             offsetof(struct vdev, vdev_dtl_node));
 356         vd->vdev_stat.vs_timestamp = gethrtime();
 357         vdev_queue_init(vd);
 358         vdev_cache_init(vd);
 359 
 360         return (vd);
 361 }
 362 
 363 /*
 364  * Allocate a new vdev.  The 'alloctype' is used to control whether we are
 365  * creating a new vdev or loading an existing one - the behavior is slightly
 366  * different for each case.
 367  */
 368 int
 369 vdev_alloc(spa_t *spa, vdev_t **vdp, nvlist_t *nv, vdev_t *parent, uint_t id,
 370     int alloctype)
 371 {
 372         vdev_ops_t *ops;
 373         char *type;
 374         uint64_t guid = 0, islog, nparity;
 375         vdev_t *vd;
 376 
 377         ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL);
 378 
 379         if (nvlist_lookup_string(nv, ZPOOL_CONFIG_TYPE, &type) != 0)
 380                 return (SET_ERROR(EINVAL));
 381 
 382         if ((ops = vdev_getops(type)) == NULL)
 383                 return (SET_ERROR(EINVAL));
 384 
 385         /*
 386          * If this is a load, get the vdev guid from the nvlist.
 387          * Otherwise, vdev_alloc_common() will generate one for us.
 388          */
 389         if (alloctype == VDEV_ALLOC_LOAD) {
 390                 uint64_t label_id;
 391 
 392                 if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_ID, &label_id) ||
 393                     label_id != id)
 394                         return (SET_ERROR(EINVAL));
 395 
 396                 if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_GUID, &guid) != 0)
 397                         return (SET_ERROR(EINVAL));
 398         } else if (alloctype == VDEV_ALLOC_SPARE) {
 399                 if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_GUID, &guid) != 0)
 400                         return (SET_ERROR(EINVAL));
 401         } else if (alloctype == VDEV_ALLOC_L2CACHE) {
 402                 if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_GUID, &guid) != 0)
 403                         return (SET_ERROR(EINVAL));
 404         } else if (alloctype == VDEV_ALLOC_ROOTPOOL) {
 405                 if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_GUID, &guid) != 0)
 406                         return (SET_ERROR(EINVAL));
 407         }
 408 
 409         /*
 410          * The first allocated vdev must be of type 'root'.
 411          */
 412         if (ops != &vdev_root_ops && spa->spa_root_vdev == NULL)
 413                 return (SET_ERROR(EINVAL));
 414 
 415         /*
 416          * Determine whether we're a log vdev.
 417          */
 418         islog = 0;
 419         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_IS_LOG, &islog);
 420         if (islog && spa_version(spa) < SPA_VERSION_SLOGS)
 421                 return (SET_ERROR(ENOTSUP));
 422 
 423         if (ops == &vdev_hole_ops && spa_version(spa) < SPA_VERSION_HOLES)
 424                 return (SET_ERROR(ENOTSUP));
 425 
 426         /*
 427          * Set the nparity property for RAID-Z vdevs.
 428          */
 429         nparity = -1ULL;
 430         if (ops == &vdev_raidz_ops) {
 431                 if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_NPARITY,
 432                     &nparity) == 0) {
 433                         if (nparity == 0 || nparity > VDEV_RAIDZ_MAXPARITY)
 434                                 return (SET_ERROR(EINVAL));
 435                         /*
 436                          * Previous versions could only support 1 or 2 parity
 437                          * device.
 438                          */
 439                         if (nparity > 1 &&
 440                             spa_version(spa) < SPA_VERSION_RAIDZ2)
 441                                 return (SET_ERROR(ENOTSUP));
 442                         if (nparity > 2 &&
 443                             spa_version(spa) < SPA_VERSION_RAIDZ3)
 444                                 return (SET_ERROR(ENOTSUP));
 445                 } else {
 446                         /*
 447                          * We require the parity to be specified for SPAs that
 448                          * support multiple parity levels.
 449                          */
 450                         if (spa_version(spa) >= SPA_VERSION_RAIDZ2)
 451                                 return (SET_ERROR(EINVAL));
 452                         /*
 453                          * Otherwise, we default to 1 parity device for RAID-Z.
 454                          */
 455                         nparity = 1;
 456                 }
 457         } else {
 458                 nparity = 0;
 459         }
 460         ASSERT(nparity != -1ULL);
 461 
 462         vd = vdev_alloc_common(spa, id, guid, ops);
 463 
 464         vd->vdev_islog = islog;
 465         vd->vdev_nparity = nparity;
 466 
 467         if (nvlist_lookup_string(nv, ZPOOL_CONFIG_PATH, &vd->vdev_path) == 0)
 468                 vd->vdev_path = spa_strdup(vd->vdev_path);
 469         if (nvlist_lookup_string(nv, ZPOOL_CONFIG_DEVID, &vd->vdev_devid) == 0)
 470                 vd->vdev_devid = spa_strdup(vd->vdev_devid);
 471         if (nvlist_lookup_string(nv, ZPOOL_CONFIG_PHYS_PATH,
 472             &vd->vdev_physpath) == 0)
 473                 vd->vdev_physpath = spa_strdup(vd->vdev_physpath);
 474         if (nvlist_lookup_string(nv, ZPOOL_CONFIG_FRU, &vd->vdev_fru) == 0)
 475                 vd->vdev_fru = spa_strdup(vd->vdev_fru);
 476 
 477         /*
 478          * Set the whole_disk property.  If it's not specified, leave the value
 479          * as -1.
 480          */
 481         if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_WHOLE_DISK,
 482             &vd->vdev_wholedisk) != 0)
 483                 vd->vdev_wholedisk = -1ULL;
 484 
 485         /*
 486          * Look for the 'not present' flag.  This will only be set if the device
 487          * was not present at the time of import.
 488          */
 489         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_NOT_PRESENT,
 490             &vd->vdev_not_present);
 491 
 492         /*
 493          * Get the alignment requirement.
 494          */
 495         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_ASHIFT, &vd->vdev_ashift);
 496 
 497         /*
 498          * Retrieve the vdev creation time.
 499          */
 500         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_CREATE_TXG,
 501             &vd->vdev_crtxg);
 502 
 503         /*
 504          * If we're a top-level vdev, try to load the allocation parameters.
 505          */
 506         if (parent && !parent->vdev_parent &&
 507             (alloctype == VDEV_ALLOC_LOAD || alloctype == VDEV_ALLOC_SPLIT)) {
 508                 (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_METASLAB_ARRAY,
 509                     &vd->vdev_ms_array);
 510                 (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_METASLAB_SHIFT,
 511                     &vd->vdev_ms_shift);
 512                 (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_ASIZE,
 513                     &vd->vdev_asize);
 514                 (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_REMOVING,
 515                     &vd->vdev_removing);
 516         }
 517 
 518         if (parent && !parent->vdev_parent && alloctype != VDEV_ALLOC_ATTACH) {
 519                 ASSERT(alloctype == VDEV_ALLOC_LOAD ||
 520                     alloctype == VDEV_ALLOC_ADD ||
 521                     alloctype == VDEV_ALLOC_SPLIT ||
 522                     alloctype == VDEV_ALLOC_ROOTPOOL);
 523                 vd->vdev_mg = metaslab_group_create(islog ?
 524                     spa_log_class(spa) : spa_normal_class(spa), vd);
 525         }
 526 
 527         /*
 528          * If we're a leaf vdev, try to load the DTL object and other state.
 529          */
 530         if (vd->vdev_ops->vdev_op_leaf &&
 531             (alloctype == VDEV_ALLOC_LOAD || alloctype == VDEV_ALLOC_L2CACHE ||
 532             alloctype == VDEV_ALLOC_ROOTPOOL)) {
 533                 if (alloctype == VDEV_ALLOC_LOAD) {
 534                         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_DTL,
 535                             &vd->vdev_dtl_object);
 536                         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_UNSPARE,
 537                             &vd->vdev_unspare);
 538                 }
 539 
 540                 if (alloctype == VDEV_ALLOC_ROOTPOOL) {
 541                         uint64_t spare = 0;
 542 
 543                         if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_IS_SPARE,
 544                             &spare) == 0 && spare)
 545                                 spa_spare_add(vd);
 546                 }
 547 
 548                 (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_OFFLINE,
 549                     &vd->vdev_offline);
 550 
 551                 (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_RESILVER_TXG,
 552                     &vd->vdev_resilver_txg);
 553 
 554                 /*
 555                  * When importing a pool, we want to ignore the persistent fault
 556                  * state, as the diagnosis made on another system may not be
 557                  * valid in the current context.  Local vdevs will
 558                  * remain in the faulted state.
 559                  */
 560                 if (spa_load_state(spa) == SPA_LOAD_OPEN) {
 561                         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_FAULTED,
 562                             &vd->vdev_faulted);
 563                         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_DEGRADED,
 564                             &vd->vdev_degraded);
 565                         (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_REMOVED,
 566                             &vd->vdev_removed);
 567 
 568                         if (vd->vdev_faulted || vd->vdev_degraded) {
 569                                 char *aux;
 570 
 571                                 vd->vdev_label_aux =
 572                                     VDEV_AUX_ERR_EXCEEDED;
 573                                 if (nvlist_lookup_string(nv,
 574                                     ZPOOL_CONFIG_AUX_STATE, &aux) == 0 &&
 575                                     strcmp(aux, "external") == 0)
 576                                         vd->vdev_label_aux = VDEV_AUX_EXTERNAL;
 577                         }
 578                 }
 579         }
 580 
 581         /*
 582          * Add ourselves to the parent's list of children.
 583          */
 584         vdev_add_child(parent, vd);
 585 
 586         *vdp = vd;
 587 
 588         return (0);
 589 }
 590 
 591 void
 592 vdev_free(vdev_t *vd)
 593 {
 594         spa_t *spa = vd->vdev_spa;
 595 
 596         /*
 597          * vdev_free() implies closing the vdev first.  This is simpler than
 598          * trying to ensure complicated semantics for all callers.
 599          */
 600         vdev_close(vd);
 601 
 602         ASSERT(!list_link_active(&vd->vdev_config_dirty_node));
 603         ASSERT(!list_link_active(&vd->vdev_state_dirty_node));
 604 
 605         /*
 606          * Free all children.
 607          */
 608         for (int c = 0; c < vd->vdev_children; c++)
 609                 vdev_free(vd->vdev_child[c]);
 610 
 611         ASSERT(vd->vdev_child == NULL);
 612         ASSERT(vd->vdev_guid_sum == vd->vdev_guid);
 613 
 614         /*
 615          * Discard allocation state.
 616          */
 617         if (vd->vdev_mg != NULL) {
 618                 vdev_metaslab_fini(vd);
 619                 metaslab_group_destroy(vd->vdev_mg);
 620         }
 621 
 622         ASSERT0(vd->vdev_stat.vs_space);
 623         ASSERT0(vd->vdev_stat.vs_dspace);
 624         ASSERT0(vd->vdev_stat.vs_alloc);
 625 
 626         /*
 627          * Remove this vdev from its parent's child list.
 628          */
 629         vdev_remove_child(vd->vdev_parent, vd);
 630 
 631         ASSERT(vd->vdev_parent == NULL);
 632 
 633         /*
 634          * Clean up vdev structure.
 635          */
 636         vdev_queue_fini(vd);
 637         vdev_cache_fini(vd);
 638 
 639         if (vd->vdev_path)
 640                 spa_strfree(vd->vdev_path);
 641         if (vd->vdev_devid)
 642                 spa_strfree(vd->vdev_devid);
 643         if (vd->vdev_physpath)
 644                 spa_strfree(vd->vdev_physpath);
 645         if (vd->vdev_fru)
 646                 spa_strfree(vd->vdev_fru);
 647 
 648         if (vd->vdev_isspare)
 649                 spa_spare_remove(vd);
 650         if (vd->vdev_isl2cache)
 651                 spa_l2cache_remove(vd);
 652 
 653         txg_list_destroy(&vd->vdev_ms_list);
 654         txg_list_destroy(&vd->vdev_dtl_list);
 655 
 656         mutex_enter(&vd->vdev_dtl_lock);
 657         space_map_close(vd->vdev_dtl_sm);
 658         for (int t = 0; t < DTL_TYPES; t++) {
 659                 range_tree_vacate(vd->vdev_dtl[t], NULL, NULL);
 660                 range_tree_destroy(vd->vdev_dtl[t]);
 661         }
 662         mutex_exit(&vd->vdev_dtl_lock);
 663 
 664         mutex_destroy(&vd->vdev_dtl_lock);
 665         mutex_destroy(&vd->vdev_stat_lock);
 666         mutex_destroy(&vd->vdev_probe_lock);
 667 
 668         if (vd == spa->spa_root_vdev)
 669                 spa->spa_root_vdev = NULL;
 670 
 671         kmem_free(vd, sizeof (vdev_t));
 672 }
 673 
 674 /*
 675  * Transfer top-level vdev state from svd to tvd.
 676  */
 677 static void
 678 vdev_top_transfer(vdev_t *svd, vdev_t *tvd)
 679 {
 680         spa_t *spa = svd->vdev_spa;
 681         metaslab_t *msp;
 682         vdev_t *vd;
 683         int t;
 684 
 685         ASSERT(tvd == tvd->vdev_top);
 686 
 687         tvd->vdev_ms_array = svd->vdev_ms_array;
 688         tvd->vdev_ms_shift = svd->vdev_ms_shift;
 689         tvd->vdev_ms_count = svd->vdev_ms_count;
 690 
 691         svd->vdev_ms_array = 0;
 692         svd->vdev_ms_shift = 0;
 693         svd->vdev_ms_count = 0;
 694 
 695         if (tvd->vdev_mg)
 696                 ASSERT3P(tvd->vdev_mg, ==, svd->vdev_mg);
 697         tvd->vdev_mg = svd->vdev_mg;
 698         tvd->vdev_ms = svd->vdev_ms;
 699 
 700         svd->vdev_mg = NULL;
 701         svd->vdev_ms = NULL;
 702 
 703         if (tvd->vdev_mg != NULL)
 704                 tvd->vdev_mg->mg_vd = tvd;
 705 
 706         tvd->vdev_stat.vs_alloc = svd->vdev_stat.vs_alloc;
 707         tvd->vdev_stat.vs_space = svd->vdev_stat.vs_space;
 708         tvd->vdev_stat.vs_dspace = svd->vdev_stat.vs_dspace;
 709 
 710         svd->vdev_stat.vs_alloc = 0;
 711         svd->vdev_stat.vs_space = 0;
 712         svd->vdev_stat.vs_dspace = 0;
 713 
 714         for (t = 0; t < TXG_SIZE; t++) {
 715                 while ((msp = txg_list_remove(&svd->vdev_ms_list, t)) != NULL)
 716                         (void) txg_list_add(&tvd->vdev_ms_list, msp, t);
 717                 while ((vd = txg_list_remove(&svd->vdev_dtl_list, t)) != NULL)
 718                         (void) txg_list_add(&tvd->vdev_dtl_list, vd, t);
 719                 if (txg_list_remove_this(&spa->spa_vdev_txg_list, svd, t))
 720                         (void) txg_list_add(&spa->spa_vdev_txg_list, tvd, t);
 721         }
 722 
 723         if (list_link_active(&svd->vdev_config_dirty_node)) {
 724                 vdev_config_clean(svd);
 725                 vdev_config_dirty(tvd);
 726         }
 727 
 728         if (list_link_active(&svd->vdev_state_dirty_node)) {
 729                 vdev_state_clean(svd);
 730                 vdev_state_dirty(tvd);
 731         }
 732 
 733         tvd->vdev_deflate_ratio = svd->vdev_deflate_ratio;
 734         svd->vdev_deflate_ratio = 0;
 735 
 736         tvd->vdev_islog = svd->vdev_islog;
 737         svd->vdev_islog = 0;
 738 }
 739 
 740 static void
 741 vdev_top_update(vdev_t *tvd, vdev_t *vd)
 742 {
 743         if (vd == NULL)
 744                 return;
 745 
 746         vd->vdev_top = tvd;
 747 
 748         for (int c = 0; c < vd->vdev_children; c++)
 749                 vdev_top_update(tvd, vd->vdev_child[c]);
 750 }
 751 
 752 /*
 753  * Add a mirror/replacing vdev above an existing vdev.
 754  */
 755 vdev_t *
 756 vdev_add_parent(vdev_t *cvd, vdev_ops_t *ops)
 757 {
 758         spa_t *spa = cvd->vdev_spa;
 759         vdev_t *pvd = cvd->vdev_parent;
 760         vdev_t *mvd;
 761 
 762         ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL);
 763 
 764         mvd = vdev_alloc_common(spa, cvd->vdev_id, 0, ops);
 765 
 766         mvd->vdev_asize = cvd->vdev_asize;
 767         mvd->vdev_min_asize = cvd->vdev_min_asize;
 768         mvd->vdev_max_asize = cvd->vdev_max_asize;
 769         mvd->vdev_ashift = cvd->vdev_ashift;
 770         mvd->vdev_state = cvd->vdev_state;
 771         mvd->vdev_crtxg = cvd->vdev_crtxg;
 772 
 773         vdev_remove_child(pvd, cvd);
 774         vdev_add_child(pvd, mvd);
 775         cvd->vdev_id = mvd->vdev_children;
 776         vdev_add_child(mvd, cvd);
 777         vdev_top_update(cvd->vdev_top, cvd->vdev_top);
 778 
 779         if (mvd == mvd->vdev_top)
 780                 vdev_top_transfer(cvd, mvd);
 781 
 782         return (mvd);
 783 }
 784 
 785 /*
 786  * Remove a 1-way mirror/replacing vdev from the tree.
 787  */
 788 void
 789 vdev_remove_parent(vdev_t *cvd)
 790 {
 791         vdev_t *mvd = cvd->vdev_parent;
 792         vdev_t *pvd = mvd->vdev_parent;
 793 
 794         ASSERT(spa_config_held(cvd->vdev_spa, SCL_ALL, RW_WRITER) == SCL_ALL);
 795 
 796         ASSERT(mvd->vdev_children == 1);
 797         ASSERT(mvd->vdev_ops == &vdev_mirror_ops ||
 798             mvd->vdev_ops == &vdev_replacing_ops ||
 799             mvd->vdev_ops == &vdev_spare_ops);
 800         cvd->vdev_ashift = mvd->vdev_ashift;
 801 
 802         vdev_remove_child(mvd, cvd);
 803         vdev_remove_child(pvd, mvd);
 804 
 805         /*
 806          * If cvd will replace mvd as a top-level vdev, preserve mvd's guid.
 807          * Otherwise, we could have detached an offline device, and when we
 808          * go to import the pool we'll think we have two top-level vdevs,
 809          * instead of a different version of the same top-level vdev.
 810          */
 811         if (mvd->vdev_top == mvd) {
 812                 uint64_t guid_delta = mvd->vdev_guid - cvd->vdev_guid;
 813                 cvd->vdev_orig_guid = cvd->vdev_guid;
 814                 cvd->vdev_guid += guid_delta;
 815                 cvd->vdev_guid_sum += guid_delta;
 816         }
 817         cvd->vdev_id = mvd->vdev_id;
 818         vdev_add_child(pvd, cvd);
 819         vdev_top_update(cvd->vdev_top, cvd->vdev_top);
 820 
 821         if (cvd == cvd->vdev_top)
 822                 vdev_top_transfer(mvd, cvd);
 823 
 824         ASSERT(mvd->vdev_children == 0);
 825         vdev_free(mvd);
 826 }
 827 
 828 int
 829 vdev_metaslab_init(vdev_t *vd, uint64_t txg)
 830 {
 831         spa_t *spa = vd->vdev_spa;
 832         objset_t *mos = spa->spa_meta_objset;
 833         uint64_t m;
 834         uint64_t oldc = vd->vdev_ms_count;
 835         uint64_t newc = vd->vdev_asize >> vd->vdev_ms_shift;
 836         metaslab_t **mspp;
 837         int error;
 838 
 839         ASSERT(txg == 0 || spa_config_held(spa, SCL_ALLOC, RW_WRITER));
 840 
 841         /*
 842          * This vdev is not being allocated from yet or is a hole.
 843          */
 844         if (vd->vdev_ms_shift == 0)
 845                 return (0);
 846 
 847         ASSERT(!vd->vdev_ishole);
 848 
 849         /*
 850          * Compute the raidz-deflation ratio.  Note, we hard-code
 851          * in 128k (1 << 17) because it is the "typical" blocksize.
 852          * Even though SPA_MAXBLOCKSIZE changed, this algorithm can not change,
 853          * otherwise it would inconsistently account for existing bp's.
 854          */
 855         vd->vdev_deflate_ratio = (1 << 17) /
 856             (vdev_psize_to_asize(vd, 1 << 17) >> SPA_MINBLOCKSHIFT);
 857 
 858         ASSERT(oldc <= newc);
 859 
 860         mspp = kmem_zalloc(newc * sizeof (*mspp), KM_SLEEP);
 861 
 862         if (oldc != 0) {
 863                 bcopy(vd->vdev_ms, mspp, oldc * sizeof (*mspp));
 864                 kmem_free(vd->vdev_ms, oldc * sizeof (*mspp));
 865         }
 866 
 867         vd->vdev_ms = mspp;
 868         vd->vdev_ms_count = newc;
 869 
 870         for (m = oldc; m < newc; m++) {
 871                 uint64_t object = 0;
 872 
 873                 if (txg == 0) {
 874                         error = dmu_read(mos, vd->vdev_ms_array,
 875                             m * sizeof (uint64_t), sizeof (uint64_t), &object,
 876                             DMU_READ_PREFETCH);
 877                         if (error)
 878                                 return (error);
 879                 }
 880 
 881                 error = metaslab_init(vd->vdev_mg, m, object, txg,
 882                     &(vd->vdev_ms[m]));
 883                 if (error)
 884                         return (error);
 885         }
 886 
 887         if (txg == 0)
 888                 spa_config_enter(spa, SCL_ALLOC, FTAG, RW_WRITER);
 889 
 890         /*
 891          * If the vdev is being removed we don't activate
 892          * the metaslabs since we want to ensure that no new
 893          * allocations are performed on this device.
 894          */
 895         if (oldc == 0 && !vd->vdev_removing)
 896                 metaslab_group_activate(vd->vdev_mg);
 897 
 898         if (txg == 0)
 899                 spa_config_exit(spa, SCL_ALLOC, FTAG);
 900 
 901         return (0);
 902 }
 903 
 904 void
 905 vdev_metaslab_fini(vdev_t *vd)
 906 {
 907         uint64_t m;
 908         uint64_t count = vd->vdev_ms_count;
 909 
 910         if (vd->vdev_ms != NULL) {
 911                 metaslab_group_passivate(vd->vdev_mg);
 912                 for (m = 0; m < count; m++) {
 913                         metaslab_t *msp = vd->vdev_ms[m];
 914 
 915                         if (msp != NULL)
 916                                 metaslab_fini(msp);
 917                 }
 918                 kmem_free(vd->vdev_ms, count * sizeof (metaslab_t *));
 919                 vd->vdev_ms = NULL;
 920         }
 921 }
 922 
 923 typedef struct vdev_probe_stats {
 924         boolean_t       vps_readable;
 925         boolean_t       vps_writeable;
 926         int             vps_flags;
 927 } vdev_probe_stats_t;
 928 
 929 static void
 930 vdev_probe_done(zio_t *zio)
 931 {
 932         spa_t *spa = zio->io_spa;
 933         vdev_t *vd = zio->io_vd;
 934         vdev_probe_stats_t *vps = zio->io_private;
 935 
 936         ASSERT(vd->vdev_probe_zio != NULL);
 937 
 938         if (zio->io_type == ZIO_TYPE_READ) {
 939                 if (zio->io_error == 0)
 940                         vps->vps_readable = 1;
 941                 if (zio->io_error == 0 && spa_writeable(spa)) {
 942                         zio_nowait(zio_write_phys(vd->vdev_probe_zio, vd,
 943                             zio->io_offset, zio->io_size, zio->io_data,
 944                             ZIO_CHECKSUM_OFF, vdev_probe_done, vps,
 945                             ZIO_PRIORITY_SYNC_WRITE, vps->vps_flags, B_TRUE));
 946                 } else {
 947                         zio_buf_free(zio->io_data, zio->io_size);
 948                 }
 949         } else if (zio->io_type == ZIO_TYPE_WRITE) {
 950                 if (zio->io_error == 0)
 951                         vps->vps_writeable = 1;
 952                 zio_buf_free(zio->io_data, zio->io_size);
 953         } else if (zio->io_type == ZIO_TYPE_NULL) {
 954                 zio_t *pio;
 955 
 956                 vd->vdev_cant_read |= !vps->vps_readable;
 957                 vd->vdev_cant_write |= !vps->vps_writeable;
 958 
 959                 if (vdev_readable(vd) &&
 960                     (vdev_writeable(vd) || !spa_writeable(spa))) {
 961                         zio->io_error = 0;
 962                 } else {
 963                         ASSERT(zio->io_error != 0);
 964                         zfs_ereport_post(FM_EREPORT_ZFS_PROBE_FAILURE,
 965                             spa, vd, NULL, 0, 0);
 966                         zio->io_error = SET_ERROR(ENXIO);
 967                 }
 968 
 969                 mutex_enter(&vd->vdev_probe_lock);
 970                 ASSERT(vd->vdev_probe_zio == zio);
 971                 vd->vdev_probe_zio = NULL;
 972                 mutex_exit(&vd->vdev_probe_lock);
 973 
 974                 while ((pio = zio_walk_parents(zio)) != NULL)
 975                         if (!vdev_accessible(vd, pio))
 976                                 pio->io_error = SET_ERROR(ENXIO);
 977 
 978                 kmem_free(vps, sizeof (*vps));
 979         }
 980 }
 981 
 982 /*
 983  * Determine whether this device is accessible.
 984  *
 985  * Read and write to several known locations: the pad regions of each
 986  * vdev label but the first, which we leave alone in case it contains
 987  * a VTOC.
 988  */
 989 zio_t *
 990 vdev_probe(vdev_t *vd, zio_t *zio)
 991 {
 992         spa_t *spa = vd->vdev_spa;
 993         vdev_probe_stats_t *vps = NULL;
 994         zio_t *pio;
 995 
 996         ASSERT(vd->vdev_ops->vdev_op_leaf);
 997 
 998         /*
 999          * Don't probe the probe.
1000          */
1001         if (zio && (zio->io_flags & ZIO_FLAG_PROBE))
1002                 return (NULL);
1003 
1004         /*
1005          * To prevent 'probe storms' when a device fails, we create
1006          * just one probe i/o at a time.  All zios that want to probe
1007          * this vdev will become parents of the probe io.
1008          */
1009         mutex_enter(&vd->vdev_probe_lock);
1010 
1011         if ((pio = vd->vdev_probe_zio) == NULL) {
1012                 vps = kmem_zalloc(sizeof (*vps), KM_SLEEP);
1013 
1014                 vps->vps_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_PROBE |
1015                     ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_AGGREGATE |
1016                     ZIO_FLAG_TRYHARD;
1017 
1018                 if (spa_config_held(spa, SCL_ZIO, RW_WRITER)) {
1019                         /*
1020                          * vdev_cant_read and vdev_cant_write can only
1021                          * transition from TRUE to FALSE when we have the
1022                          * SCL_ZIO lock as writer; otherwise they can only
1023                          * transition from FALSE to TRUE.  This ensures that
1024                          * any zio looking at these values can assume that
1025                          * failures persist for the life of the I/O.  That's
1026                          * important because when a device has intermittent
1027                          * connectivity problems, we want to ensure that
1028                          * they're ascribed to the device (ENXIO) and not
1029                          * the zio (EIO).
1030                          *
1031                          * Since we hold SCL_ZIO as writer here, clear both
1032                          * values so the probe can reevaluate from first
1033                          * principles.
1034                          */
1035                         vps->vps_flags |= ZIO_FLAG_CONFIG_WRITER;
1036                         vd->vdev_cant_read = B_FALSE;
1037                         vd->vdev_cant_write = B_FALSE;
1038                 }
1039 
1040                 vd->vdev_probe_zio = pio = zio_null(NULL, spa, vd,
1041                     vdev_probe_done, vps,
1042                     vps->vps_flags | ZIO_FLAG_DONT_PROPAGATE);
1043 
1044                 /*
1045                  * We can't change the vdev state in this context, so we
1046                  * kick off an async task to do it on our behalf.
1047                  */
1048                 if (zio != NULL) {
1049                         vd->vdev_probe_wanted = B_TRUE;
1050                         spa_async_request(spa, SPA_ASYNC_PROBE);
1051                 }
1052         }
1053 
1054         if (zio != NULL)
1055                 zio_add_child(zio, pio);
1056 
1057         mutex_exit(&vd->vdev_probe_lock);
1058 
1059         if (vps == NULL) {
1060                 ASSERT(zio != NULL);
1061                 return (NULL);
1062         }
1063 
1064         for (int l = 1; l < VDEV_LABELS; l++) {
1065                 zio_nowait(zio_read_phys(pio, vd,
1066                     vdev_label_offset(vd->vdev_psize, l,
1067                     offsetof(vdev_label_t, vl_pad2)),
1068                     VDEV_PAD_SIZE, zio_buf_alloc(VDEV_PAD_SIZE),
1069                     ZIO_CHECKSUM_OFF, vdev_probe_done, vps,
1070                     ZIO_PRIORITY_SYNC_READ, vps->vps_flags, B_TRUE));
1071         }
1072 
1073         if (zio == NULL)
1074                 return (pio);
1075 
1076         zio_nowait(pio);
1077         return (NULL);
1078 }
1079 
1080 static void
1081 vdev_open_child(void *arg)
1082 {
1083         vdev_t *vd = arg;
1084 
1085         vd->vdev_open_thread = curthread;
1086         vd->vdev_open_error = vdev_open(vd);
1087         vd->vdev_open_thread = NULL;
1088 }
1089 
1090 boolean_t
1091 vdev_uses_zvols(vdev_t *vd)
1092 {
1093         if (vd->vdev_path && strncmp(vd->vdev_path, ZVOL_DIR,
1094             strlen(ZVOL_DIR)) == 0)
1095                 return (B_TRUE);
1096         for (int c = 0; c < vd->vdev_children; c++)
1097                 if (vdev_uses_zvols(vd->vdev_child[c]))
1098                         return (B_TRUE);
1099         return (B_FALSE);
1100 }
1101 
1102 void
1103 vdev_open_children(vdev_t *vd)
1104 {
1105         taskq_t *tq;
1106         int children = vd->vdev_children;
1107 
1108         /*
1109          * in order to handle pools on top of zvols, do the opens
1110          * in a single thread so that the same thread holds the
1111          * spa_namespace_lock
1112          */
1113         if (vdev_uses_zvols(vd)) {
1114                 for (int c = 0; c < children; c++)
1115                         vd->vdev_child[c]->vdev_open_error =
1116                             vdev_open(vd->vdev_child[c]);
1117                 return;
1118         }
1119         tq = taskq_create("vdev_open", children, minclsyspri,
1120             children, children, TASKQ_PREPOPULATE);
1121 
1122         for (int c = 0; c < children; c++)
1123                 VERIFY(taskq_dispatch(tq, vdev_open_child, vd->vdev_child[c],
1124                     TQ_SLEEP) != NULL);
1125 
1126         taskq_destroy(tq);
1127 }
1128 
1129 /*
1130  * Prepare a virtual device for access.
1131  */
1132 int
1133 vdev_open(vdev_t *vd)
1134 {
1135         spa_t *spa = vd->vdev_spa;
1136         int error;
1137         uint64_t osize = 0;
1138         uint64_t max_osize = 0;
1139         uint64_t asize, max_asize, psize;
1140         uint64_t ashift = 0;
1141 
1142         ASSERT(vd->vdev_open_thread == curthread ||
1143             spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
1144         ASSERT(vd->vdev_state == VDEV_STATE_CLOSED ||
1145             vd->vdev_state == VDEV_STATE_CANT_OPEN ||
1146             vd->vdev_state == VDEV_STATE_OFFLINE);
1147 
1148         vd->vdev_stat.vs_aux = VDEV_AUX_NONE;
1149         vd->vdev_cant_read = B_FALSE;
1150         vd->vdev_cant_write = B_FALSE;
1151         vd->vdev_min_asize = vdev_get_min_asize(vd);
1152 
1153         /*
1154          * If this vdev is not removed, check its fault status.  If it's
1155          * faulted, bail out of the open.
1156          */
1157         if (!vd->vdev_removed && vd->vdev_faulted) {
1158                 ASSERT(vd->vdev_children == 0);
1159                 ASSERT(vd->vdev_label_aux == VDEV_AUX_ERR_EXCEEDED ||
1160                     vd->vdev_label_aux == VDEV_AUX_EXTERNAL);
1161                 vdev_set_state(vd, B_TRUE, VDEV_STATE_FAULTED,
1162                     vd->vdev_label_aux);
1163                 return (SET_ERROR(ENXIO));
1164         } else if (vd->vdev_offline) {
1165                 ASSERT(vd->vdev_children == 0);
1166                 vdev_set_state(vd, B_TRUE, VDEV_STATE_OFFLINE, VDEV_AUX_NONE);
1167                 return (SET_ERROR(ENXIO));
1168         }
1169 
1170         error = vd->vdev_ops->vdev_op_open(vd, &osize, &max_osize, &ashift);
1171 
1172         /*
1173          * Reset the vdev_reopening flag so that we actually close
1174          * the vdev on error.
1175          */
1176         vd->vdev_reopening = B_FALSE;
1177         if (zio_injection_enabled && error == 0)
1178                 error = zio_handle_device_injection(vd, NULL, ENXIO);
1179 
1180         if (error) {
1181                 if (vd->vdev_removed &&
1182                     vd->vdev_stat.vs_aux != VDEV_AUX_OPEN_FAILED)
1183                         vd->vdev_removed = B_FALSE;
1184 
1185                 vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
1186                     vd->vdev_stat.vs_aux);
1187                 return (error);
1188         }
1189 
1190         vd->vdev_removed = B_FALSE;
1191 
1192         /*
1193          * Recheck the faulted flag now that we have confirmed that
1194          * the vdev is accessible.  If we're faulted, bail.
1195          */
1196         if (vd->vdev_faulted) {
1197                 ASSERT(vd->vdev_children == 0);
1198                 ASSERT(vd->vdev_label_aux == VDEV_AUX_ERR_EXCEEDED ||
1199                     vd->vdev_label_aux == VDEV_AUX_EXTERNAL);
1200                 vdev_set_state(vd, B_TRUE, VDEV_STATE_FAULTED,
1201                     vd->vdev_label_aux);
1202                 return (SET_ERROR(ENXIO));
1203         }
1204 
1205         if (vd->vdev_degraded) {
1206                 ASSERT(vd->vdev_children == 0);
1207                 vdev_set_state(vd, B_TRUE, VDEV_STATE_DEGRADED,
1208                     VDEV_AUX_ERR_EXCEEDED);
1209         } else {
1210                 vdev_set_state(vd, B_TRUE, VDEV_STATE_HEALTHY, 0);
1211         }
1212 
1213         /*
1214          * For hole or missing vdevs we just return success.
1215          */
1216         if (vd->vdev_ishole || vd->vdev_ops == &vdev_missing_ops)
1217                 return (0);
1218 
1219         for (int c = 0; c < vd->vdev_children; c++) {
1220                 if (vd->vdev_child[c]->vdev_state != VDEV_STATE_HEALTHY) {
1221                         vdev_set_state(vd, B_TRUE, VDEV_STATE_DEGRADED,
1222                             VDEV_AUX_NONE);
1223                         break;
1224                 }
1225         }
1226 
1227         osize = P2ALIGN(osize, (uint64_t)sizeof (vdev_label_t));
1228         max_osize = P2ALIGN(max_osize, (uint64_t)sizeof (vdev_label_t));
1229 
1230         if (vd->vdev_children == 0) {
1231                 if (osize < SPA_MINDEVSIZE) {
1232                         vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
1233                             VDEV_AUX_TOO_SMALL);
1234                         return (SET_ERROR(EOVERFLOW));
1235                 }
1236                 psize = osize;
1237                 asize = osize - (VDEV_LABEL_START_SIZE + VDEV_LABEL_END_SIZE);
1238                 max_asize = max_osize - (VDEV_LABEL_START_SIZE +
1239                     VDEV_LABEL_END_SIZE);
1240         } else {
1241                 if (vd->vdev_parent != NULL && osize < SPA_MINDEVSIZE -
1242                     (VDEV_LABEL_START_SIZE + VDEV_LABEL_END_SIZE)) {
1243                         vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
1244                             VDEV_AUX_TOO_SMALL);
1245                         return (SET_ERROR(EOVERFLOW));
1246                 }
1247                 psize = 0;
1248                 asize = osize;
1249                 max_asize = max_osize;
1250         }
1251 
1252         vd->vdev_psize = psize;
1253 
1254         /*
1255          * Make sure the allocatable size hasn't shrunk.
1256          */
1257         if (asize < vd->vdev_min_asize) {
1258                 vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
1259                     VDEV_AUX_BAD_LABEL);
1260                 return (SET_ERROR(EINVAL));
1261         }
1262 
1263         if (vd->vdev_asize == 0) {
1264                 /*
1265                  * This is the first-ever open, so use the computed values.
1266                  * For testing purposes, a higher ashift can be requested.
1267                  */
1268                 vd->vdev_asize = asize;
1269                 vd->vdev_max_asize = max_asize;
1270                 vd->vdev_ashift = MAX(ashift, vd->vdev_ashift);
1271         } else {
1272                 /*
1273                  * Detect if the alignment requirement has increased.
1274                  * We don't want to make the pool unavailable, just
1275                  * issue a warning instead.
1276                  */
1277                 if (ashift > vd->vdev_top->vdev_ashift &&
1278                     vd->vdev_ops->vdev_op_leaf) {
1279                         cmn_err(CE_WARN,
1280                             "Disk, '%s', has a block alignment that is "
1281                             "larger than the pool's alignment\n",
1282                             vd->vdev_path);
1283                 }
1284                 vd->vdev_max_asize = max_asize;
1285         }
1286 
1287         /*
1288          * If all children are healthy and the asize has increased,
1289          * then we've experienced dynamic LUN growth.  If automatic
1290          * expansion is enabled then use the additional space.
1291          */
1292         if (vd->vdev_state == VDEV_STATE_HEALTHY && asize > vd->vdev_asize &&
1293             (vd->vdev_expanding || spa->spa_autoexpand))
1294                 vd->vdev_asize = asize;
1295 
1296         vdev_set_min_asize(vd);
1297 
1298         /*
1299          * Ensure we can issue some IO before declaring the
1300          * vdev open for business.
1301          */
1302         if (vd->vdev_ops->vdev_op_leaf &&
1303             (error = zio_wait(vdev_probe(vd, NULL))) != 0) {
1304                 vdev_set_state(vd, B_TRUE, VDEV_STATE_FAULTED,
1305                     VDEV_AUX_ERR_EXCEEDED);
1306                 return (error);
1307         }
1308 
1309         /*
1310          * If a leaf vdev has a DTL, and seems healthy, then kick off a
1311          * resilver.  But don't do this if we are doing a reopen for a scrub,
1312          * since this would just restart the scrub we are already doing.
1313          */
1314         if (vd->vdev_ops->vdev_op_leaf && !spa->spa_scrub_reopen &&
1315             vdev_resilver_needed(vd, NULL, NULL))
1316                 spa_async_request(spa, SPA_ASYNC_RESILVER);
1317 
1318         return (0);
1319 }
1320 
1321 /*
1322  * Called once the vdevs are all opened, this routine validates the label
1323  * contents.  This needs to be done before vdev_load() so that we don't
1324  * inadvertently do repair I/Os to the wrong device.
1325  *
1326  * If 'strict' is false ignore the spa guid check. This is necessary because
1327  * if the machine crashed during a re-guid the new guid might have been written
1328  * to all of the vdev labels, but not the cached config. The strict check
1329  * will be performed when the pool is opened again using the mos config.
1330  *
1331  * This function will only return failure if one of the vdevs indicates that it
1332  * has since been destroyed or exported.  This is only possible if
1333  * /etc/zfs/zpool.cache was readonly at the time.  Otherwise, the vdev state
1334  * will be updated but the function will return 0.
1335  */
1336 int
1337 vdev_validate(vdev_t *vd, boolean_t strict)
1338 {
1339         spa_t *spa = vd->vdev_spa;
1340         nvlist_t *label;
1341         uint64_t guid = 0, top_guid;
1342         uint64_t state;
1343 
1344         for (int c = 0; c < vd->vdev_children; c++)
1345                 if (vdev_validate(vd->vdev_child[c], strict) != 0)
1346                         return (SET_ERROR(EBADF));
1347 
1348         /*
1349          * If the device has already failed, or was marked offline, don't do
1350          * any further validation.  Otherwise, label I/O will fail and we will
1351          * overwrite the previous state.
1352          */
1353         if (vd->vdev_ops->vdev_op_leaf && vdev_readable(vd)) {
1354                 uint64_t aux_guid = 0;
1355                 nvlist_t *nvl;
1356                 uint64_t txg = spa_last_synced_txg(spa) != 0 ?
1357                     spa_last_synced_txg(spa) : -1ULL;
1358 
1359                 if ((label = vdev_label_read_config(vd, txg)) == NULL) {
1360                         vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
1361                             VDEV_AUX_BAD_LABEL);
1362                         return (0);
1363                 }
1364 
1365                 /*
1366                  * Determine if this vdev has been split off into another
1367                  * pool.  If so, then refuse to open it.
1368                  */
1369                 if (nvlist_lookup_uint64(label, ZPOOL_CONFIG_SPLIT_GUID,
1370                     &aux_guid) == 0 && aux_guid == spa_guid(spa)) {
1371                         vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
1372                             VDEV_AUX_SPLIT_POOL);
1373                         nvlist_free(label);
1374                         return (0);
1375                 }
1376 
1377                 if (strict && (nvlist_lookup_uint64(label,
1378                     ZPOOL_CONFIG_POOL_GUID, &guid) != 0 ||
1379                     guid != spa_guid(spa))) {
1380                         vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
1381                             VDEV_AUX_CORRUPT_DATA);
1382                         nvlist_free(label);
1383                         return (0);
1384                 }
1385 
1386                 if (nvlist_lookup_nvlist(label, ZPOOL_CONFIG_VDEV_TREE, &nvl)
1387                     != 0 || nvlist_lookup_uint64(nvl, ZPOOL_CONFIG_ORIG_GUID,
1388                     &aux_guid) != 0)
1389                         aux_guid = 0;
1390 
1391                 /*
1392                  * If this vdev just became a top-level vdev because its
1393                  * sibling was detached, it will have adopted the parent's
1394                  * vdev guid -- but the label may or may not be on disk yet.
1395                  * Fortunately, either version of the label will have the
1396                  * same top guid, so if we're a top-level vdev, we can
1397                  * safely compare to that instead.
1398                  *
1399                  * If we split this vdev off instead, then we also check the
1400                  * original pool's guid.  We don't want to consider the vdev
1401                  * corrupt if it is partway through a split operation.
1402                  */
1403                 if (nvlist_lookup_uint64(label, ZPOOL_CONFIG_GUID,
1404                     &guid) != 0 ||
1405                     nvlist_lookup_uint64(label, ZPOOL_CONFIG_TOP_GUID,
1406                     &top_guid) != 0 ||
1407                     ((vd->vdev_guid != guid && vd->vdev_guid != aux_guid) &&
1408                     (vd->vdev_guid != top_guid || vd != vd->vdev_top))) {
1409                         vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
1410                             VDEV_AUX_CORRUPT_DATA);
1411                         nvlist_free(label);
1412                         return (0);
1413                 }
1414 
1415                 if (nvlist_lookup_uint64(label, ZPOOL_CONFIG_POOL_STATE,
1416                     &state) != 0) {
1417                         vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
1418                             VDEV_AUX_CORRUPT_DATA);
1419                         nvlist_free(label);
1420                         return (0);
1421                 }
1422 
1423                 nvlist_free(label);
1424 
1425                 /*
1426                  * If this is a verbatim import, no need to check the
1427                  * state of the pool.
1428                  */
1429                 if (!(spa->spa_import_flags & ZFS_IMPORT_VERBATIM) &&
1430                     spa_load_state(spa) == SPA_LOAD_OPEN &&
1431                     state != POOL_STATE_ACTIVE)
1432                         return (SET_ERROR(EBADF));
1433 
1434                 /*
1435                  * If we were able to open and validate a vdev that was
1436                  * previously marked permanently unavailable, clear that state
1437                  * now.
1438                  */
1439                 if (vd->vdev_not_present)
1440                         vd->vdev_not_present = 0;
1441         }
1442 
1443         return (0);
1444 }
1445 
1446 /*
1447  * Close a virtual device.
1448  */
1449 void
1450 vdev_close(vdev_t *vd)
1451 {
1452         spa_t *spa = vd->vdev_spa;
1453         vdev_t *pvd = vd->vdev_parent;
1454 
1455         ASSERT(spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
1456 
1457         /*
1458          * If our parent is reopening, then we are as well, unless we are
1459          * going offline.
1460          */
1461         if (pvd != NULL && pvd->vdev_reopening)
1462                 vd->vdev_reopening = (pvd->vdev_reopening && !vd->vdev_offline);
1463 
1464         vd->vdev_ops->vdev_op_close(vd);
1465 
1466         vdev_cache_purge(vd);
1467 
1468         /*
1469          * We record the previous state before we close it, so that if we are
1470          * doing a reopen(), we don't generate FMA ereports if we notice that
1471          * it's still faulted.
1472          */
1473         vd->vdev_prevstate = vd->vdev_state;
1474 
1475         if (vd->vdev_offline)
1476                 vd->vdev_state = VDEV_STATE_OFFLINE;
1477         else
1478                 vd->vdev_state = VDEV_STATE_CLOSED;
1479         vd->vdev_stat.vs_aux = VDEV_AUX_NONE;
1480 }
1481 
1482 void
1483 vdev_hold(vdev_t *vd)
1484 {
1485         spa_t *spa = vd->vdev_spa;
1486 
1487         ASSERT(spa_is_root(spa));
1488         if (spa->spa_state == POOL_STATE_UNINITIALIZED)
1489                 return;
1490 
1491         for (int c = 0; c < vd->vdev_children; c++)
1492                 vdev_hold(vd->vdev_child[c]);
1493 
1494         if (vd->vdev_ops->vdev_op_leaf)
1495                 vd->vdev_ops->vdev_op_hold(vd);
1496 }
1497 
1498 void
1499 vdev_rele(vdev_t *vd)
1500 {
1501         spa_t *spa = vd->vdev_spa;
1502 
1503         ASSERT(spa_is_root(spa));
1504         for (int c = 0; c < vd->vdev_children; c++)
1505                 vdev_rele(vd->vdev_child[c]);
1506 
1507         if (vd->vdev_ops->vdev_op_leaf)
1508                 vd->vdev_ops->vdev_op_rele(vd);
1509 }
1510 
1511 /*
1512  * Reopen all interior vdevs and any unopened leaves.  We don't actually
1513  * reopen leaf vdevs which had previously been opened as they might deadlock
1514  * on the spa_config_lock.  Instead we only obtain the leaf's physical size.
1515  * If the leaf has never been opened then open it, as usual.
1516  */
1517 void
1518 vdev_reopen(vdev_t *vd)
1519 {
1520         spa_t *spa = vd->vdev_spa;
1521 
1522         ASSERT(spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
1523 
1524         /* set the reopening flag unless we're taking the vdev offline */
1525         vd->vdev_reopening = !vd->vdev_offline;
1526         vdev_close(vd);
1527         (void) vdev_open(vd);
1528 
1529         /*
1530          * Call vdev_validate() here to make sure we have the same device.
1531          * Otherwise, a device with an invalid label could be successfully
1532          * opened in response to vdev_reopen().
1533          */
1534         if (vd->vdev_aux) {
1535                 (void) vdev_validate_aux(vd);
1536                 if (vdev_readable(vd) && vdev_writeable(vd) &&
1537                     vd->vdev_aux == &spa->spa_l2cache &&
1538                     !l2arc_vdev_present(vd))
1539                         l2arc_add_vdev(spa, vd);
1540         } else {
1541                 (void) vdev_validate(vd, B_TRUE);
1542         }
1543 
1544         /*
1545          * Reassess parent vdev's health.
1546          */
1547         vdev_propagate_state(vd);
1548 }
1549 
1550 int
1551 vdev_create(vdev_t *vd, uint64_t txg, boolean_t isreplacing)
1552 {
1553         int error;
1554 
1555         /*
1556          * Normally, partial opens (e.g. of a mirror) are allowed.
1557          * For a create, however, we want to fail the request if
1558          * there are any components we can't open.
1559          */
1560         error = vdev_open(vd);
1561 
1562         if (error || vd->vdev_state != VDEV_STATE_HEALTHY) {
1563                 vdev_close(vd);
1564                 return (error ? error : ENXIO);
1565         }
1566 
1567         /*
1568          * Recursively load DTLs and initialize all labels.
1569          */
1570         if ((error = vdev_dtl_load(vd)) != 0 ||
1571             (error = vdev_label_init(vd, txg, isreplacing ?
1572             VDEV_LABEL_REPLACE : VDEV_LABEL_CREATE)) != 0) {
1573                 vdev_close(vd);
1574                 return (error);
1575         }
1576 
1577         return (0);
1578 }
1579 
1580 void
1581 vdev_metaslab_set_size(vdev_t *vd)
1582 {
1583         /*
1584          * Aim for roughly metaslabs_per_vdev (default 200) metaslabs per vdev.
1585          */
1586         vd->vdev_ms_shift = highbit64(vd->vdev_asize / metaslabs_per_vdev);
1587         vd->vdev_ms_shift = MAX(vd->vdev_ms_shift, SPA_MAXBLOCKSHIFT);
1588 }
1589 
1590 void
1591 vdev_dirty(vdev_t *vd, int flags, void *arg, uint64_t txg)
1592 {
1593         ASSERT(vd == vd->vdev_top);
1594         ASSERT(!vd->vdev_ishole);
1595         ASSERT(ISP2(flags));
1596         ASSERT(spa_writeable(vd->vdev_spa));
1597 
1598         if (flags & VDD_METASLAB)
1599                 (void) txg_list_add(&vd->vdev_ms_list, arg, txg);
1600 
1601         if (flags & VDD_DTL)
1602                 (void) txg_list_add(&vd->vdev_dtl_list, arg, txg);
1603 
1604         (void) txg_list_add(&vd->vdev_spa->spa_vdev_txg_list, vd, txg);
1605 }
1606 
1607 void
1608 vdev_dirty_leaves(vdev_t *vd, int flags, uint64_t txg)
1609 {
1610         for (int c = 0; c < vd->vdev_children; c++)
1611                 vdev_dirty_leaves(vd->vdev_child[c], flags, txg);
1612 
1613         if (vd->vdev_ops->vdev_op_leaf)
1614                 vdev_dirty(vd->vdev_top, flags, vd, txg);
1615 }
1616 
1617 /*
1618  * DTLs.
1619  *
1620  * A vdev's DTL (dirty time log) is the set of transaction groups for which
1621  * the vdev has less than perfect replication.  There are four kinds of DTL:
1622  *
1623  * DTL_MISSING: txgs for which the vdev has no valid copies of the data
1624  *
1625  * DTL_PARTIAL: txgs for which data is available, but not fully replicated
1626  *
1627  * DTL_SCRUB: the txgs that could not be repaired by the last scrub; upon
1628  *      scrub completion, DTL_SCRUB replaces DTL_MISSING in the range of
1629  *      txgs that was scrubbed.
1630  *
1631  * DTL_OUTAGE: txgs which cannot currently be read, whether due to
1632  *      persistent errors or just some device being offline.
1633  *      Unlike the other three, the DTL_OUTAGE map is not generally
1634  *      maintained; it's only computed when needed, typically to
1635  *      determine whether a device can be detached.
1636  *
1637  * For leaf vdevs, DTL_MISSING and DTL_PARTIAL are identical: the device
1638  * either has the data or it doesn't.
1639  *
1640  * For interior vdevs such as mirror and RAID-Z the picture is more complex.
1641  * A vdev's DTL_PARTIAL is the union of its children's DTL_PARTIALs, because
1642  * if any child is less than fully replicated, then so is its parent.
1643  * A vdev's DTL_MISSING is a modified union of its children's DTL_MISSINGs,
1644  * comprising only those txgs which appear in 'maxfaults' or more children;
1645  * those are the txgs we don't have enough replication to read.  For example,
1646  * double-parity RAID-Z can tolerate up to two missing devices (maxfaults == 2);
1647  * thus, its DTL_MISSING consists of the set of txgs that appear in more than
1648  * two child DTL_MISSING maps.
1649  *
1650  * It should be clear from the above that to compute the DTLs and outage maps
1651  * for all vdevs, it suffices to know just the leaf vdevs' DTL_MISSING maps.
1652  * Therefore, that is all we keep on disk.  When loading the pool, or after
1653  * a configuration change, we generate all other DTLs from first principles.
1654  */
1655 void
1656 vdev_dtl_dirty(vdev_t *vd, vdev_dtl_type_t t, uint64_t txg, uint64_t size)
1657 {
1658         range_tree_t *rt = vd->vdev_dtl[t];
1659 
1660         ASSERT(t < DTL_TYPES);
1661         ASSERT(vd != vd->vdev_spa->spa_root_vdev);
1662         ASSERT(spa_writeable(vd->vdev_spa));
1663 
1664         mutex_enter(rt->rt_lock);
1665         if (!range_tree_contains(rt, txg, size))
1666                 range_tree_add(rt, txg, size);
1667         mutex_exit(rt->rt_lock);
1668 }
1669 
1670 boolean_t
1671 vdev_dtl_contains(vdev_t *vd, vdev_dtl_type_t t, uint64_t txg, uint64_t size)
1672 {
1673         range_tree_t *rt = vd->vdev_dtl[t];
1674         boolean_t dirty = B_FALSE;
1675 
1676         ASSERT(t < DTL_TYPES);
1677         ASSERT(vd != vd->vdev_spa->spa_root_vdev);
1678 
1679         mutex_enter(rt->rt_lock);
1680         if (range_tree_space(rt) != 0)
1681                 dirty = range_tree_contains(rt, txg, size);
1682         mutex_exit(rt->rt_lock);
1683 
1684         return (dirty);
1685 }
1686 
1687 boolean_t
1688 vdev_dtl_empty(vdev_t *vd, vdev_dtl_type_t t)
1689 {
1690         range_tree_t *rt = vd->vdev_dtl[t];
1691         boolean_t empty;
1692 
1693         mutex_enter(rt->rt_lock);
1694         empty = (range_tree_space(rt) == 0);
1695         mutex_exit(rt->rt_lock);
1696 
1697         return (empty);
1698 }
1699 
1700 /*
1701  * Returns the lowest txg in the DTL range.
1702  */
1703 static uint64_t
1704 vdev_dtl_min(vdev_t *vd)
1705 {
1706         range_seg_t *rs;
1707 
1708         ASSERT(MUTEX_HELD(&vd->vdev_dtl_lock));
1709         ASSERT3U(range_tree_space(vd->vdev_dtl[DTL_MISSING]), !=, 0);
1710         ASSERT0(vd->vdev_children);
1711 
1712         rs = avl_first(&vd->vdev_dtl[DTL_MISSING]->rt_root);
1713         return (rs->rs_start - 1);
1714 }
1715 
1716 /*
1717  * Returns the highest txg in the DTL.
1718  */
1719 static uint64_t
1720 vdev_dtl_max(vdev_t *vd)
1721 {
1722         range_seg_t *rs;
1723 
1724         ASSERT(MUTEX_HELD(&vd->vdev_dtl_lock));
1725         ASSERT3U(range_tree_space(vd->vdev_dtl[DTL_MISSING]), !=, 0);
1726         ASSERT0(vd->vdev_children);
1727 
1728         rs = avl_last(&vd->vdev_dtl[DTL_MISSING]->rt_root);
1729         return (rs->rs_end);
1730 }
1731 
1732 /*
1733  * Determine if a resilvering vdev should remove any DTL entries from
1734  * its range. If the vdev was resilvering for the entire duration of the
1735  * scan then it should excise that range from its DTLs. Otherwise, this
1736  * vdev is considered partially resilvered and should leave its DTL
1737  * entries intact. The comment in vdev_dtl_reassess() describes how we
1738  * excise the DTLs.
1739  */
1740 static boolean_t
1741 vdev_dtl_should_excise(vdev_t *vd)
1742 {
1743         spa_t *spa = vd->vdev_spa;
1744         dsl_scan_t *scn = spa->spa_dsl_pool->dp_scan;
1745 
1746         ASSERT0(scn->scn_phys.scn_errors);
1747         ASSERT0(vd->vdev_children);
1748 
1749         if (vd->vdev_resilver_txg == 0 ||
1750             range_tree_space(vd->vdev_dtl[DTL_MISSING]) == 0)
1751                 return (B_TRUE);
1752 
1753         /*
1754          * When a resilver is initiated the scan will assign the scn_max_txg
1755          * value to the highest txg value that exists in all DTLs. If this
1756          * device's max DTL is not part of this scan (i.e. it is not in
1757          * the range (scn_min_txg, scn_max_txg] then it is not eligible
1758          * for excision.
1759          */
1760         if (vdev_dtl_max(vd) <= scn->scn_phys.scn_max_txg) {
1761                 ASSERT3U(scn->scn_phys.scn_min_txg, <=, vdev_dtl_min(vd));
1762                 ASSERT3U(scn->scn_phys.scn_min_txg, <, vd->vdev_resilver_txg);
1763                 ASSERT3U(vd->vdev_resilver_txg, <=, scn->scn_phys.scn_max_txg);
1764                 return (B_TRUE);
1765         }
1766         return (B_FALSE);
1767 }
1768 
1769 /*
1770  * Reassess DTLs after a config change or scrub completion.
1771  */
1772 void
1773 vdev_dtl_reassess(vdev_t *vd, uint64_t txg, uint64_t scrub_txg, int scrub_done)
1774 {
1775         spa_t *spa = vd->vdev_spa;
1776         avl_tree_t reftree;
1777         int minref;
1778 
1779         ASSERT(spa_config_held(spa, SCL_ALL, RW_READER) != 0);
1780 
1781         for (int c = 0; c < vd->vdev_children; c++)
1782                 vdev_dtl_reassess(vd->vdev_child[c], txg,
1783                     scrub_txg, scrub_done);
1784 
1785         if (vd == spa->spa_root_vdev || vd->vdev_ishole || vd->vdev_aux)
1786                 return;
1787 
1788         if (vd->vdev_ops->vdev_op_leaf) {
1789                 dsl_scan_t *scn = spa->spa_dsl_pool->dp_scan;
1790 
1791                 mutex_enter(&vd->vdev_dtl_lock);
1792 
1793                 /*
1794                  * If we've completed a scan cleanly then determine
1795                  * if this vdev should remove any DTLs. We only want to
1796                  * excise regions on vdevs that were available during
1797                  * the entire duration of this scan.
1798                  */
1799                 if (scrub_txg != 0 &&
1800                     (spa->spa_scrub_started ||
1801                     (scn != NULL && scn->scn_phys.scn_errors == 0)) &&
1802                     vdev_dtl_should_excise(vd)) {
1803                         /*
1804                          * We completed a scrub up to scrub_txg.  If we
1805                          * did it without rebooting, then the scrub dtl
1806                          * will be valid, so excise the old region and
1807                          * fold in the scrub dtl.  Otherwise, leave the
1808                          * dtl as-is if there was an error.
1809                          *
1810                          * There's little trick here: to excise the beginning
1811                          * of the DTL_MISSING map, we put it into a reference
1812                          * tree and then add a segment with refcnt -1 that
1813                          * covers the range [0, scrub_txg).  This means
1814                          * that each txg in that range has refcnt -1 or 0.
1815                          * We then add DTL_SCRUB with a refcnt of 2, so that
1816                          * entries in the range [0, scrub_txg) will have a
1817                          * positive refcnt -- either 1 or 2.  We then convert
1818                          * the reference tree into the new DTL_MISSING map.
1819                          */
1820                         space_reftree_create(&reftree);
1821                         space_reftree_add_map(&reftree,
1822                             vd->vdev_dtl[DTL_MISSING], 1);
1823                         space_reftree_add_seg(&reftree, 0, scrub_txg, -1);
1824                         space_reftree_add_map(&reftree,
1825                             vd->vdev_dtl[DTL_SCRUB], 2);
1826                         space_reftree_generate_map(&reftree,
1827                             vd->vdev_dtl[DTL_MISSING], 1);
1828                         space_reftree_destroy(&reftree);
1829                 }
1830                 range_tree_vacate(vd->vdev_dtl[DTL_PARTIAL], NULL, NULL);
1831                 range_tree_walk(vd->vdev_dtl[DTL_MISSING],
1832                     range_tree_add, vd->vdev_dtl[DTL_PARTIAL]);
1833                 if (scrub_done)
1834                         range_tree_vacate(vd->vdev_dtl[DTL_SCRUB], NULL, NULL);
1835                 range_tree_vacate(vd->vdev_dtl[DTL_OUTAGE], NULL, NULL);
1836                 if (!vdev_readable(vd))
1837                         range_tree_add(vd->vdev_dtl[DTL_OUTAGE], 0, -1ULL);
1838                 else
1839                         range_tree_walk(vd->vdev_dtl[DTL_MISSING],
1840                             range_tree_add, vd->vdev_dtl[DTL_OUTAGE]);
1841 
1842                 /*
1843                  * If the vdev was resilvering and no longer has any
1844                  * DTLs then reset its resilvering flag.
1845                  */
1846                 if (vd->vdev_resilver_txg != 0 &&
1847                     range_tree_space(vd->vdev_dtl[DTL_MISSING]) == 0 &&
1848                     range_tree_space(vd->vdev_dtl[DTL_OUTAGE]) == 0)
1849                         vd->vdev_resilver_txg = 0;
1850 
1851                 mutex_exit(&vd->vdev_dtl_lock);
1852 
1853                 if (txg != 0)
1854                         vdev_dirty(vd->vdev_top, VDD_DTL, vd, txg);
1855                 return;
1856         }
1857 
1858         mutex_enter(&vd->vdev_dtl_lock);
1859         for (int t = 0; t < DTL_TYPES; t++) {
1860                 /* account for child's outage in parent's missing map */
1861                 int s = (t == DTL_MISSING) ? DTL_OUTAGE: t;
1862                 if (t == DTL_SCRUB)
1863                         continue;                       /* leaf vdevs only */
1864                 if (t == DTL_PARTIAL)
1865                         minref = 1;                     /* i.e. non-zero */
1866                 else if (vd->vdev_nparity != 0)
1867                         minref = vd->vdev_nparity + 1;       /* RAID-Z */
1868                 else
1869                         minref = vd->vdev_children;  /* any kind of mirror */
1870                 space_reftree_create(&reftree);
1871                 for (int c = 0; c < vd->vdev_children; c++) {
1872                         vdev_t *cvd = vd->vdev_child[c];
1873                         mutex_enter(&cvd->vdev_dtl_lock);
1874                         space_reftree_add_map(&reftree, cvd->vdev_dtl[s], 1);
1875                         mutex_exit(&cvd->vdev_dtl_lock);
1876                 }
1877                 space_reftree_generate_map(&reftree, vd->vdev_dtl[t], minref);
1878                 space_reftree_destroy(&reftree);
1879         }
1880         mutex_exit(&vd->vdev_dtl_lock);
1881 }
1882 
1883 int
1884 vdev_dtl_load(vdev_t *vd)
1885 {
1886         spa_t *spa = vd->vdev_spa;
1887         objset_t *mos = spa->spa_meta_objset;
1888         int error = 0;
1889 
1890         if (vd->vdev_ops->vdev_op_leaf && vd->vdev_dtl_object != 0) {
1891                 ASSERT(!vd->vdev_ishole);
1892 
1893                 error = space_map_open(&vd->vdev_dtl_sm, mos,
1894                     vd->vdev_dtl_object, 0, -1ULL, 0, &vd->vdev_dtl_lock);
1895                 if (error)
1896                         return (error);
1897                 ASSERT(vd->vdev_dtl_sm != NULL);
1898 
1899                 mutex_enter(&vd->vdev_dtl_lock);
1900 
1901                 /*
1902                  * Now that we've opened the space_map we need to update
1903                  * the in-core DTL.
1904                  */
1905                 space_map_update(vd->vdev_dtl_sm);
1906 
1907                 error = space_map_load(vd->vdev_dtl_sm,
1908                     vd->vdev_dtl[DTL_MISSING], SM_ALLOC);
1909                 mutex_exit(&vd->vdev_dtl_lock);
1910 
1911                 return (error);
1912         }
1913 
1914         for (int c = 0; c < vd->vdev_children; c++) {
1915                 error = vdev_dtl_load(vd->vdev_child[c]);
1916                 if (error != 0)
1917                         break;
1918         }
1919 
1920         return (error);
1921 }
1922 
1923 void
1924 vdev_dtl_sync(vdev_t *vd, uint64_t txg)
1925 {
1926         spa_t *spa = vd->vdev_spa;
1927         range_tree_t *rt = vd->vdev_dtl[DTL_MISSING];
1928         objset_t *mos = spa->spa_meta_objset;
1929         range_tree_t *rtsync;
1930         kmutex_t rtlock;
1931         dmu_tx_t *tx;
1932         uint64_t object = space_map_object(vd->vdev_dtl_sm);
1933 
1934         ASSERT(!vd->vdev_ishole);
1935         ASSERT(vd->vdev_ops->vdev_op_leaf);
1936 
1937         tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg);
1938 
1939         if (vd->vdev_detached || vd->vdev_top->vdev_removing) {
1940                 mutex_enter(&vd->vdev_dtl_lock);
1941                 space_map_free(vd->vdev_dtl_sm, tx);
1942                 space_map_close(vd->vdev_dtl_sm);
1943                 vd->vdev_dtl_sm = NULL;
1944                 mutex_exit(&vd->vdev_dtl_lock);
1945                 dmu_tx_commit(tx);
1946                 return;
1947         }
1948 
1949         if (vd->vdev_dtl_sm == NULL) {
1950                 uint64_t new_object;
1951 
1952                 new_object = space_map_alloc(mos, tx);
1953                 VERIFY3U(new_object, !=, 0);
1954 
1955                 VERIFY0(space_map_open(&vd->vdev_dtl_sm, mos, new_object,
1956                     0, -1ULL, 0, &vd->vdev_dtl_lock));
1957                 ASSERT(vd->vdev_dtl_sm != NULL);
1958         }
1959 
1960         mutex_init(&rtlock, NULL, MUTEX_DEFAULT, NULL);
1961 
1962         rtsync = range_tree_create(NULL, NULL, &rtlock);
1963 
1964         mutex_enter(&rtlock);
1965 
1966         mutex_enter(&vd->vdev_dtl_lock);
1967         range_tree_walk(rt, range_tree_add, rtsync);
1968         mutex_exit(&vd->vdev_dtl_lock);
1969 
1970         space_map_truncate(vd->vdev_dtl_sm, tx);
1971         space_map_write(vd->vdev_dtl_sm, rtsync, SM_ALLOC, tx);
1972         range_tree_vacate(rtsync, NULL, NULL);
1973 
1974         range_tree_destroy(rtsync);
1975 
1976         mutex_exit(&rtlock);
1977         mutex_destroy(&rtlock);
1978 
1979         /*
1980          * If the object for the space map has changed then dirty
1981          * the top level so that we update the config.
1982          */
1983         if (object != space_map_object(vd->vdev_dtl_sm)) {
1984                 zfs_dbgmsg("txg %llu, spa %s, DTL old object %llu, "
1985                     "new object %llu", txg, spa_name(spa), object,
1986                     space_map_object(vd->vdev_dtl_sm));
1987                 vdev_config_dirty(vd->vdev_top);
1988         }
1989 
1990         dmu_tx_commit(tx);
1991 
1992         mutex_enter(&vd->vdev_dtl_lock);
1993         space_map_update(vd->vdev_dtl_sm);
1994         mutex_exit(&vd->vdev_dtl_lock);
1995 }
1996 
1997 /*
1998  * Determine whether the specified vdev can be offlined/detached/removed
1999  * without losing data.
2000  */
2001 boolean_t
2002 vdev_dtl_required(vdev_t *vd)
2003 {
2004         spa_t *spa = vd->vdev_spa;
2005         vdev_t *tvd = vd->vdev_top;
2006         uint8_t cant_read = vd->vdev_cant_read;
2007         boolean_t required;
2008 
2009         ASSERT(spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
2010 
2011         if (vd == spa->spa_root_vdev || vd == tvd)
2012                 return (B_TRUE);
2013 
2014         /*
2015          * Temporarily mark the device as unreadable, and then determine
2016          * whether this results in any DTL outages in the top-level vdev.
2017          * If not, we can safely offline/detach/remove the device.
2018          */
2019         vd->vdev_cant_read = B_TRUE;
2020         vdev_dtl_reassess(tvd, 0, 0, B_FALSE);
2021         required = !vdev_dtl_empty(tvd, DTL_OUTAGE);
2022         vd->vdev_cant_read = cant_read;
2023         vdev_dtl_reassess(tvd, 0, 0, B_FALSE);
2024 
2025         if (!required && zio_injection_enabled)
2026                 required = !!zio_handle_device_injection(vd, NULL, ECHILD);
2027 
2028         return (required);
2029 }
2030 
2031 /*
2032  * Determine if resilver is needed, and if so the txg range.
2033  */
2034 boolean_t
2035 vdev_resilver_needed(vdev_t *vd, uint64_t *minp, uint64_t *maxp)
2036 {
2037         boolean_t needed = B_FALSE;
2038         uint64_t thismin = UINT64_MAX;
2039         uint64_t thismax = 0;
2040 
2041         if (vd->vdev_children == 0) {
2042                 mutex_enter(&vd->vdev_dtl_lock);
2043                 if (range_tree_space(vd->vdev_dtl[DTL_MISSING]) != 0 &&
2044                     vdev_writeable(vd)) {
2045 
2046                         thismin = vdev_dtl_min(vd);
2047                         thismax = vdev_dtl_max(vd);
2048                         needed = B_TRUE;
2049                 }
2050                 mutex_exit(&vd->vdev_dtl_lock);
2051         } else {
2052                 for (int c = 0; c < vd->vdev_children; c++) {
2053                         vdev_t *cvd = vd->vdev_child[c];
2054                         uint64_t cmin, cmax;
2055 
2056                         if (vdev_resilver_needed(cvd, &cmin, &cmax)) {
2057                                 thismin = MIN(thismin, cmin);
2058                                 thismax = MAX(thismax, cmax);
2059                                 needed = B_TRUE;
2060                         }
2061                 }
2062         }
2063 
2064         if (needed && minp) {
2065                 *minp = thismin;
2066                 *maxp = thismax;
2067         }
2068         return (needed);
2069 }
2070 
2071 void
2072 vdev_load(vdev_t *vd)
2073 {
2074         /*
2075          * Recursively load all children.
2076          */
2077         for (int c = 0; c < vd->vdev_children; c++)
2078                 vdev_load(vd->vdev_child[c]);
2079 
2080         /*
2081          * If this is a top-level vdev, initialize its metaslabs.
2082          */
2083         if (vd == vd->vdev_top && !vd->vdev_ishole &&
2084             (vd->vdev_ashift == 0 || vd->vdev_asize == 0 ||
2085             vdev_metaslab_init(vd, 0) != 0))
2086                 vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
2087                     VDEV_AUX_CORRUPT_DATA);
2088 
2089         /*
2090          * If this is a leaf vdev, load its DTL.
2091          */
2092         if (vd->vdev_ops->vdev_op_leaf && vdev_dtl_load(vd) != 0)
2093                 vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
2094                     VDEV_AUX_CORRUPT_DATA);
2095 }
2096 
2097 /*
2098  * The special vdev case is used for hot spares and l2cache devices.  Its
2099  * sole purpose it to set the vdev state for the associated vdev.  To do this,
2100  * we make sure that we can open the underlying device, then try to read the
2101  * label, and make sure that the label is sane and that it hasn't been
2102  * repurposed to another pool.
2103  */
2104 int
2105 vdev_validate_aux(vdev_t *vd)
2106 {
2107         nvlist_t *label;
2108         uint64_t guid, version;
2109         uint64_t state;
2110 
2111         if (!vdev_readable(vd))
2112                 return (0);
2113 
2114         if ((label = vdev_label_read_config(vd, -1ULL)) == NULL) {
2115                 vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
2116                     VDEV_AUX_CORRUPT_DATA);
2117                 return (-1);
2118         }
2119 
2120         if (nvlist_lookup_uint64(label, ZPOOL_CONFIG_VERSION, &version) != 0 ||
2121             !SPA_VERSION_IS_SUPPORTED(version) ||
2122             nvlist_lookup_uint64(label, ZPOOL_CONFIG_GUID, &guid) != 0 ||
2123             guid != vd->vdev_guid ||
2124             nvlist_lookup_uint64(label, ZPOOL_CONFIG_POOL_STATE, &state) != 0) {
2125                 vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
2126                     VDEV_AUX_CORRUPT_DATA);
2127                 nvlist_free(label);
2128                 return (-1);
2129         }
2130 
2131         /*
2132          * We don't actually check the pool state here.  If it's in fact in
2133          * use by another pool, we update this fact on the fly when requested.
2134          */
2135         nvlist_free(label);
2136         return (0);
2137 }
2138 
2139 void
2140 vdev_remove(vdev_t *vd, uint64_t txg)
2141 {
2142         spa_t *spa = vd->vdev_spa;
2143         objset_t *mos = spa->spa_meta_objset;
2144         dmu_tx_t *tx;
2145 
2146         tx = dmu_tx_create_assigned(spa_get_dsl(spa), txg);
2147 
2148         if (vd->vdev_ms != NULL) {
2149                 metaslab_group_t *mg = vd->vdev_mg;
2150 
2151                 metaslab_group_histogram_verify(mg);
2152                 metaslab_class_histogram_verify(mg->mg_class);
2153 
2154                 for (int m = 0; m < vd->vdev_ms_count; m++) {
2155                         metaslab_t *msp = vd->vdev_ms[m];
2156 
2157                         if (msp == NULL || msp->ms_sm == NULL)
2158                                 continue;
2159 
2160                         mutex_enter(&msp->ms_lock);
2161                         /*
2162                          * If the metaslab was not loaded when the vdev
2163                          * was removed then the histogram accounting may
2164                          * not be accurate. Update the histogram information
2165                          * here so that we ensure that the metaslab group
2166                          * and metaslab class are up-to-date.
2167                          */
2168                         metaslab_group_histogram_remove(mg, msp);
2169 
2170                         VERIFY0(space_map_allocated(msp->ms_sm));
2171                         space_map_free(msp->ms_sm, tx);
2172                         space_map_close(msp->ms_sm);
2173                         msp->ms_sm = NULL;
2174                         mutex_exit(&msp->ms_lock);
2175                 }
2176 
2177                 metaslab_group_histogram_verify(mg);
2178                 metaslab_class_histogram_verify(mg->mg_class);
2179                 for (int i = 0; i < RANGE_TREE_HISTOGRAM_SIZE; i++)
2180                         ASSERT0(mg->mg_histogram[i]);
2181 
2182         }
2183 
2184         if (vd->vdev_ms_array) {
2185                 (void) dmu_object_free(mos, vd->vdev_ms_array, tx);
2186                 vd->vdev_ms_array = 0;
2187         }
2188         dmu_tx_commit(tx);
2189 }
2190 
2191 void
2192 vdev_sync_done(vdev_t *vd, uint64_t txg)
2193 {
2194         metaslab_t *msp;
2195         boolean_t reassess = !txg_list_empty(&vd->vdev_ms_list, TXG_CLEAN(txg));
2196 
2197         ASSERT(!vd->vdev_ishole);
2198 
2199         while (msp = txg_list_remove(&vd->vdev_ms_list, TXG_CLEAN(txg)))
2200                 metaslab_sync_done(msp, txg);
2201 
2202         if (reassess)
2203                 metaslab_sync_reassess(vd->vdev_mg);
2204 }
2205 
2206 void
2207 vdev_sync(vdev_t *vd, uint64_t txg)
2208 {
2209         spa_t *spa = vd->vdev_spa;
2210         vdev_t *lvd;
2211         metaslab_t *msp;
2212         dmu_tx_t *tx;
2213 
2214         ASSERT(!vd->vdev_ishole);
2215 
2216         if (vd->vdev_ms_array == 0 && vd->vdev_ms_shift != 0) {
2217                 ASSERT(vd == vd->vdev_top);
2218                 tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg);
2219                 vd->vdev_ms_array = dmu_object_alloc(spa->spa_meta_objset,
2220                     DMU_OT_OBJECT_ARRAY, 0, DMU_OT_NONE, 0, tx);
2221                 ASSERT(vd->vdev_ms_array != 0);
2222                 vdev_config_dirty(vd);
2223                 dmu_tx_commit(tx);
2224         }
2225 
2226         /*
2227          * Remove the metadata associated with this vdev once it's empty.
2228          */
2229         if (vd->vdev_stat.vs_alloc == 0 && vd->vdev_removing)
2230                 vdev_remove(vd, txg);
2231 
2232         while ((msp = txg_list_remove(&vd->vdev_ms_list, txg)) != NULL) {
2233                 metaslab_sync(msp, txg);
2234                 (void) txg_list_add(&vd->vdev_ms_list, msp, TXG_CLEAN(txg));
2235         }
2236 
2237         while ((lvd = txg_list_remove(&vd->vdev_dtl_list, txg)) != NULL)
2238                 vdev_dtl_sync(lvd, txg);
2239 
2240         (void) txg_list_add(&spa->spa_vdev_txg_list, vd, TXG_CLEAN(txg));
2241 }
2242 
2243 uint64_t
2244 vdev_psize_to_asize(vdev_t *vd, uint64_t psize)
2245 {
2246         return (vd->vdev_ops->vdev_op_asize(vd, psize));
2247 }
2248 
2249 /*
2250  * Mark the given vdev faulted.  A faulted vdev behaves as if the device could
2251  * not be opened, and no I/O is attempted.
2252  */
2253 int
2254 vdev_fault(spa_t *spa, uint64_t guid, vdev_aux_t aux)
2255 {
2256         vdev_t *vd, *tvd;
2257 
2258         spa_vdev_state_enter(spa, SCL_NONE);
2259 
2260         if ((vd = spa_lookup_by_guid(spa, guid, B_TRUE)) == NULL)
2261                 return (spa_vdev_state_exit(spa, NULL, ENODEV));
2262 
2263         if (!vd->vdev_ops->vdev_op_leaf)
2264                 return (spa_vdev_state_exit(spa, NULL, ENOTSUP));
2265 
2266         tvd = vd->vdev_top;
2267 
2268         /*
2269          * We don't directly use the aux state here, but if we do a
2270          * vdev_reopen(), we need this value to be present to remember why we
2271          * were faulted.
2272          */
2273         vd->vdev_label_aux = aux;
2274 
2275         /*
2276          * Faulted state takes precedence over degraded.
2277          */
2278         vd->vdev_delayed_close = B_FALSE;
2279         vd->vdev_faulted = 1ULL;
2280         vd->vdev_degraded = 0ULL;
2281         vdev_set_state(vd, B_FALSE, VDEV_STATE_FAULTED, aux);
2282 
2283         /*
2284          * If this device has the only valid copy of the data, then
2285          * back off and simply mark the vdev as degraded instead.
2286          */
2287         if (!tvd->vdev_islog && vd->vdev_aux == NULL && vdev_dtl_required(vd)) {
2288                 vd->vdev_degraded = 1ULL;
2289                 vd->vdev_faulted = 0ULL;
2290 
2291                 /*
2292                  * If we reopen the device and it's not dead, only then do we
2293                  * mark it degraded.
2294                  */
2295                 vdev_reopen(tvd);
2296 
2297                 if (vdev_readable(vd))
2298                         vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED, aux);
2299         }
2300 
2301         return (spa_vdev_state_exit(spa, vd, 0));
2302 }
2303 
2304 /*
2305  * Mark the given vdev degraded.  A degraded vdev is purely an indication to the
2306  * user that something is wrong.  The vdev continues to operate as normal as far
2307  * as I/O is concerned.
2308  */
2309 int
2310 vdev_degrade(spa_t *spa, uint64_t guid, vdev_aux_t aux)
2311 {
2312         vdev_t *vd;
2313 
2314         spa_vdev_state_enter(spa, SCL_NONE);
2315 
2316         if ((vd = spa_lookup_by_guid(spa, guid, B_TRUE)) == NULL)
2317                 return (spa_vdev_state_exit(spa, NULL, ENODEV));
2318 
2319         if (!vd->vdev_ops->vdev_op_leaf)
2320                 return (spa_vdev_state_exit(spa, NULL, ENOTSUP));
2321 
2322         /*
2323          * If the vdev is already faulted, then don't do anything.
2324          */
2325         if (vd->vdev_faulted || vd->vdev_degraded)
2326                 return (spa_vdev_state_exit(spa, NULL, 0));
2327 
2328         vd->vdev_degraded = 1ULL;
2329         if (!vdev_is_dead(vd))
2330                 vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED,
2331                     aux);
2332 
2333         return (spa_vdev_state_exit(spa, vd, 0));
2334 }
2335 
2336 /*
2337  * Online the given vdev.
2338  *
2339  * If 'ZFS_ONLINE_UNSPARE' is set, it implies two things.  First, any attached
2340  * spare device should be detached when the device finishes resilvering.
2341  * Second, the online should be treated like a 'test' online case, so no FMA
2342  * events are generated if the device fails to open.
2343  */
2344 int
2345 vdev_online(spa_t *spa, uint64_t guid, uint64_t flags, vdev_state_t *newstate)
2346 {
2347         vdev_t *vd, *tvd, *pvd, *rvd = spa->spa_root_vdev;
2348 
2349         spa_vdev_state_enter(spa, SCL_NONE);
2350 
2351         if ((vd = spa_lookup_by_guid(spa, guid, B_TRUE)) == NULL)
2352                 return (spa_vdev_state_exit(spa, NULL, ENODEV));
2353 
2354         if (!vd->vdev_ops->vdev_op_leaf)
2355                 return (spa_vdev_state_exit(spa, NULL, ENOTSUP));
2356 
2357         tvd = vd->vdev_top;
2358         vd->vdev_offline = B_FALSE;
2359         vd->vdev_tmpoffline = B_FALSE;
2360         vd->vdev_checkremove = !!(flags & ZFS_ONLINE_CHECKREMOVE);
2361         vd->vdev_forcefault = !!(flags & ZFS_ONLINE_FORCEFAULT);
2362 
2363         /* XXX - L2ARC 1.0 does not support expansion */
2364         if (!vd->vdev_aux) {
2365                 for (pvd = vd; pvd != rvd; pvd = pvd->vdev_parent)
2366                         pvd->vdev_expanding = !!(flags & ZFS_ONLINE_EXPAND);
2367         }
2368 
2369         vdev_reopen(tvd);
2370         vd->vdev_checkremove = vd->vdev_forcefault = B_FALSE;
2371 
2372         if (!vd->vdev_aux) {
2373                 for (pvd = vd; pvd != rvd; pvd = pvd->vdev_parent)
2374                         pvd->vdev_expanding = B_FALSE;
2375         }
2376 
2377         if (newstate)
2378                 *newstate = vd->vdev_state;
2379         if ((flags & ZFS_ONLINE_UNSPARE) &&
2380             !vdev_is_dead(vd) && vd->vdev_parent &&
2381             vd->vdev_parent->vdev_ops == &vdev_spare_ops &&
2382             vd->vdev_parent->vdev_child[0] == vd)
2383                 vd->vdev_unspare = B_TRUE;
2384 
2385         if ((flags & ZFS_ONLINE_EXPAND) || spa->spa_autoexpand) {
2386 
2387                 /* XXX - L2ARC 1.0 does not support expansion */
2388                 if (vd->vdev_aux)
2389                         return (spa_vdev_state_exit(spa, vd, ENOTSUP));
2390                 spa_async_request(spa, SPA_ASYNC_CONFIG_UPDATE);
2391         }
2392         return (spa_vdev_state_exit(spa, vd, 0));
2393 }
2394 
2395 static int
2396 vdev_offline_locked(spa_t *spa, uint64_t guid, uint64_t flags)
2397 {
2398         vdev_t *vd, *tvd;
2399         int error = 0;
2400         uint64_t generation;
2401         metaslab_group_t *mg;
2402 
2403 top:
2404         spa_vdev_state_enter(spa, SCL_ALLOC);
2405 
2406         if ((vd = spa_lookup_by_guid(spa, guid, B_TRUE)) == NULL)
2407                 return (spa_vdev_state_exit(spa, NULL, ENODEV));
2408 
2409         if (!vd->vdev_ops->vdev_op_leaf)
2410                 return (spa_vdev_state_exit(spa, NULL, ENOTSUP));
2411 
2412         tvd = vd->vdev_top;
2413         mg = tvd->vdev_mg;
2414         generation = spa->spa_config_generation + 1;
2415 
2416         /*
2417          * If the device isn't already offline, try to offline it.
2418          */
2419         if (!vd->vdev_offline) {
2420                 /*
2421                  * If this device has the only valid copy of some data,
2422                  * don't allow it to be offlined. Log devices are always
2423                  * expendable.
2424                  */
2425                 if (!tvd->vdev_islog && vd->vdev_aux == NULL &&
2426                     vdev_dtl_required(vd))
2427                         return (spa_vdev_state_exit(spa, NULL, EBUSY));
2428 
2429                 /*
2430                  * If the top-level is a slog and it has had allocations
2431                  * then proceed.  We check that the vdev's metaslab group
2432                  * is not NULL since it's possible that we may have just
2433                  * added this vdev but not yet initialized its metaslabs.
2434                  */
2435                 if (tvd->vdev_islog && mg != NULL) {
2436                         /*
2437                          * Prevent any future allocations.
2438                          */
2439                         metaslab_group_passivate(mg);
2440                         (void) spa_vdev_state_exit(spa, vd, 0);
2441 
2442                         error = spa_offline_log(spa);
2443 
2444                         spa_vdev_state_enter(spa, SCL_ALLOC);
2445 
2446                         /*
2447                          * Check to see if the config has changed.
2448                          */
2449                         if (error || generation != spa->spa_config_generation) {
2450                                 metaslab_group_activate(mg);
2451                                 if (error)
2452                                         return (spa_vdev_state_exit(spa,
2453                                             vd, error));
2454                                 (void) spa_vdev_state_exit(spa, vd, 0);
2455                                 goto top;
2456                         }
2457                         ASSERT0(tvd->vdev_stat.vs_alloc);
2458                 }
2459 
2460                 /*
2461                  * Offline this device and reopen its top-level vdev.
2462                  * If the top-level vdev is a log device then just offline
2463                  * it. Otherwise, if this action results in the top-level
2464                  * vdev becoming unusable, undo it and fail the request.
2465                  */
2466                 vd->vdev_offline = B_TRUE;
2467                 vdev_reopen(tvd);
2468 
2469                 if (!tvd->vdev_islog && vd->vdev_aux == NULL &&
2470                     vdev_is_dead(tvd)) {
2471                         vd->vdev_offline = B_FALSE;
2472                         vdev_reopen(tvd);
2473                         return (spa_vdev_state_exit(spa, NULL, EBUSY));
2474                 }
2475 
2476                 /*
2477                  * Add the device back into the metaslab rotor so that
2478                  * once we online the device it's open for business.
2479                  */
2480                 if (tvd->vdev_islog && mg != NULL)
2481                         metaslab_group_activate(mg);
2482         }
2483 
2484         vd->vdev_tmpoffline = !!(flags & ZFS_OFFLINE_TEMPORARY);
2485 
2486         return (spa_vdev_state_exit(spa, vd, 0));
2487 }
2488 
2489 int
2490 vdev_offline(spa_t *spa, uint64_t guid, uint64_t flags)
2491 {
2492         int error;
2493 
2494         mutex_enter(&spa->spa_vdev_top_lock);
2495         error = vdev_offline_locked(spa, guid, flags);
2496         mutex_exit(&spa->spa_vdev_top_lock);
2497 
2498         return (error);
2499 }
2500 
2501 /*
2502  * Clear the error counts associated with this vdev.  Unlike vdev_online() and
2503  * vdev_offline(), we assume the spa config is locked.  We also clear all
2504  * children.  If 'vd' is NULL, then the user wants to clear all vdevs.
2505  */
2506 void
2507 vdev_clear(spa_t *spa, vdev_t *vd)
2508 {
2509         vdev_t *rvd = spa->spa_root_vdev;
2510 
2511         ASSERT(spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
2512 
2513         if (vd == NULL)
2514                 vd = rvd;
2515 
2516         vd->vdev_stat.vs_read_errors = 0;
2517         vd->vdev_stat.vs_write_errors = 0;
2518         vd->vdev_stat.vs_checksum_errors = 0;
2519 
2520         for (int c = 0; c < vd->vdev_children; c++)
2521                 vdev_clear(spa, vd->vdev_child[c]);
2522 
2523         /*
2524          * If we're in the FAULTED state or have experienced failed I/O, then
2525          * clear the persistent state and attempt to reopen the device.  We
2526          * also mark the vdev config dirty, so that the new faulted state is
2527          * written out to disk.
2528          */
2529         if (vd->vdev_faulted || vd->vdev_degraded ||
2530             !vdev_readable(vd) || !vdev_writeable(vd)) {
2531 
2532                 /*
2533                  * When reopening in reponse to a clear event, it may be due to
2534                  * a fmadm repair request.  In this case, if the device is
2535                  * still broken, we want to still post the ereport again.
2536                  */
2537                 vd->vdev_forcefault = B_TRUE;
2538 
2539                 vd->vdev_faulted = vd->vdev_degraded = 0ULL;
2540                 vd->vdev_cant_read = B_FALSE;
2541                 vd->vdev_cant_write = B_FALSE;
2542 
2543                 vdev_reopen(vd == rvd ? rvd : vd->vdev_top);
2544 
2545                 vd->vdev_forcefault = B_FALSE;
2546 
2547                 if (vd != rvd && vdev_writeable(vd->vdev_top))
2548                         vdev_state_dirty(vd->vdev_top);
2549 
2550                 if (vd->vdev_aux == NULL && !vdev_is_dead(vd))
2551                         spa_async_request(spa, SPA_ASYNC_RESILVER);
2552 
2553                 spa_event_notify(spa, vd, ESC_ZFS_VDEV_CLEAR);
2554         }
2555 
2556         /*
2557          * When clearing a FMA-diagnosed fault, we always want to
2558          * unspare the device, as we assume that the original spare was
2559          * done in response to the FMA fault.
2560          */
2561         if (!vdev_is_dead(vd) && vd->vdev_parent != NULL &&
2562             vd->vdev_parent->vdev_ops == &vdev_spare_ops &&
2563             vd->vdev_parent->vdev_child[0] == vd)
2564                 vd->vdev_unspare = B_TRUE;
2565 }
2566 
2567 boolean_t
2568 vdev_is_dead(vdev_t *vd)
2569 {
2570         /*
2571          * Holes and missing devices are always considered "dead".
2572          * This simplifies the code since we don't have to check for
2573          * these types of devices in the various code paths.
2574          * Instead we rely on the fact that we skip over dead devices
2575          * before issuing I/O to them.
2576          */
2577         return (vd->vdev_state < VDEV_STATE_DEGRADED || vd->vdev_ishole ||
2578             vd->vdev_ops == &vdev_missing_ops);
2579 }
2580 
2581 boolean_t
2582 vdev_readable(vdev_t *vd)
2583 {
2584         return (!vdev_is_dead(vd) && !vd->vdev_cant_read);
2585 }
2586 
2587 boolean_t
2588 vdev_writeable(vdev_t *vd)
2589 {
2590         return (!vdev_is_dead(vd) && !vd->vdev_cant_write);
2591 }
2592 
2593 boolean_t
2594 vdev_allocatable(vdev_t *vd)
2595 {
2596         uint64_t state = vd->vdev_state;
2597 
2598         /*
2599          * We currently allow allocations from vdevs which may be in the
2600          * process of reopening (i.e. VDEV_STATE_CLOSED). If the device
2601          * fails to reopen then we'll catch it later when we're holding
2602          * the proper locks.  Note that we have to get the vdev state
2603          * in a local variable because although it changes atomically,
2604          * we're asking two separate questions about it.
2605          */
2606         return (!(state < VDEV_STATE_DEGRADED && state != VDEV_STATE_CLOSED) &&
2607             !vd->vdev_cant_write && !vd->vdev_ishole);
2608 }
2609 
2610 boolean_t
2611 vdev_accessible(vdev_t *vd, zio_t *zio)
2612 {
2613         ASSERT(zio->io_vd == vd);
2614 
2615         if (vdev_is_dead(vd) || vd->vdev_remove_wanted)
2616                 return (B_FALSE);
2617 
2618         if (zio->io_type == ZIO_TYPE_READ)
2619                 return (!vd->vdev_cant_read);
2620 
2621         if (zio->io_type == ZIO_TYPE_WRITE)
2622                 return (!vd->vdev_cant_write);
2623 
2624         return (B_TRUE);
2625 }
2626 
2627 /*
2628  * Get statistics for the given vdev.
2629  */
2630 void
2631 vdev_get_stats(vdev_t *vd, vdev_stat_t *vs)
2632 {
2633         spa_t *spa = vd->vdev_spa;
2634         vdev_t *rvd = spa->spa_root_vdev;
2635 
2636         ASSERT(spa_config_held(spa, SCL_ALL, RW_READER) != 0);
2637 
2638         mutex_enter(&vd->vdev_stat_lock);
2639         bcopy(&vd->vdev_stat, vs, sizeof (*vs));
2640         vs->vs_timestamp = gethrtime() - vs->vs_timestamp;
2641         vs->vs_state = vd->vdev_state;
2642         vs->vs_rsize = vdev_get_min_asize(vd);
2643         if (vd->vdev_ops->vdev_op_leaf)
2644                 vs->vs_rsize += VDEV_LABEL_START_SIZE + VDEV_LABEL_END_SIZE;
2645         vs->vs_esize = vd->vdev_max_asize - vd->vdev_asize;
2646         if (vd->vdev_aux == NULL && vd == vd->vdev_top && !vd->vdev_ishole) {
2647                 vs->vs_fragmentation = vd->vdev_mg->mg_fragmentation;
2648         }
2649 
2650         /*
2651          * If we're getting stats on the root vdev, aggregate the I/O counts
2652          * over all top-level vdevs (i.e. the direct children of the root).
2653          */
2654         if (vd == rvd) {
2655                 for (int c = 0; c < rvd->vdev_children; c++) {
2656                         vdev_t *cvd = rvd->vdev_child[c];
2657                         vdev_stat_t *cvs = &cvd->vdev_stat;
2658 
2659                         for (int t = 0; t < ZIO_TYPES; t++) {
2660                                 vs->vs_ops[t] += cvs->vs_ops[t];
2661                                 vs->vs_bytes[t] += cvs->vs_bytes[t];
2662                         }
2663                         cvs->vs_scan_removing = cvd->vdev_removing;
2664                 }
2665         }
2666         mutex_exit(&vd->vdev_stat_lock);
2667 }
2668 
2669 void
2670 vdev_clear_stats(vdev_t *vd)
2671 {
2672         mutex_enter(&vd->vdev_stat_lock);
2673         vd->vdev_stat.vs_space = 0;
2674         vd->vdev_stat.vs_dspace = 0;
2675         vd->vdev_stat.vs_alloc = 0;
2676         mutex_exit(&vd->vdev_stat_lock);
2677 }
2678 
2679 void
2680 vdev_scan_stat_init(vdev_t *vd)
2681 {
2682         vdev_stat_t *vs = &vd->vdev_stat;
2683 
2684         for (int c = 0; c < vd->vdev_children; c++)
2685                 vdev_scan_stat_init(vd->vdev_child[c]);
2686 
2687         mutex_enter(&vd->vdev_stat_lock);
2688         vs->vs_scan_processed = 0;
2689         mutex_exit(&vd->vdev_stat_lock);
2690 }
2691 
2692 void
2693 vdev_stat_update(zio_t *zio, uint64_t psize)
2694 {
2695         spa_t *spa = zio->io_spa;
2696         vdev_t *rvd = spa->spa_root_vdev;
2697         vdev_t *vd = zio->io_vd ? zio->io_vd : rvd;
2698         vdev_t *pvd;
2699         uint64_t txg = zio->io_txg;
2700         vdev_stat_t *vs = &vd->vdev_stat;
2701         zio_type_t type = zio->io_type;
2702         int flags = zio->io_flags;
2703 
2704         /*
2705          * If this i/o is a gang leader, it didn't do any actual work.
2706          */
2707         if (zio->io_gang_tree)
2708                 return;
2709 
2710         if (zio->io_error == 0) {
2711                 /*
2712                  * If this is a root i/o, don't count it -- we've already
2713                  * counted the top-level vdevs, and vdev_get_stats() will
2714                  * aggregate them when asked.  This reduces contention on
2715                  * the root vdev_stat_lock and implicitly handles blocks
2716                  * that compress away to holes, for which there is no i/o.
2717                  * (Holes never create vdev children, so all the counters
2718                  * remain zero, which is what we want.)
2719                  *
2720                  * Note: this only applies to successful i/o (io_error == 0)
2721                  * because unlike i/o counts, errors are not additive.
2722                  * When reading a ditto block, for example, failure of
2723                  * one top-level vdev does not imply a root-level error.
2724                  */
2725                 if (vd == rvd)
2726                         return;
2727 
2728                 ASSERT(vd == zio->io_vd);
2729 
2730                 if (flags & ZIO_FLAG_IO_BYPASS)
2731                         return;
2732 
2733                 mutex_enter(&vd->vdev_stat_lock);
2734 
2735                 if (flags & ZIO_FLAG_IO_REPAIR) {
2736                         if (flags & ZIO_FLAG_SCAN_THREAD) {
2737                                 dsl_scan_phys_t *scn_phys =
2738                                     &spa->spa_dsl_pool->dp_scan->scn_phys;
2739                                 uint64_t *processed = &scn_phys->scn_processed;
2740 
2741                                 /* XXX cleanup? */
2742                                 if (vd->vdev_ops->vdev_op_leaf)
2743                                         atomic_add_64(processed, psize);
2744                                 vs->vs_scan_processed += psize;
2745                         }
2746 
2747                         if (flags & ZIO_FLAG_SELF_HEAL)
2748                                 vs->vs_self_healed += psize;
2749                 }
2750 
2751                 vs->vs_ops[type]++;
2752                 vs->vs_bytes[type] += psize;
2753 
2754                 mutex_exit(&vd->vdev_stat_lock);
2755                 return;
2756         }
2757 
2758         if (flags & ZIO_FLAG_SPECULATIVE)
2759                 return;
2760 
2761         /*
2762          * If this is an I/O error that is going to be retried, then ignore the
2763          * error.  Otherwise, the user may interpret B_FAILFAST I/O errors as
2764          * hard errors, when in reality they can happen for any number of
2765          * innocuous reasons (bus resets, MPxIO link failure, etc).
2766          */
2767         if (zio->io_error == EIO &&
2768             !(zio->io_flags & ZIO_FLAG_IO_RETRY))
2769                 return;
2770 
2771         /*
2772          * Intent logs writes won't propagate their error to the root
2773          * I/O so don't mark these types of failures as pool-level
2774          * errors.
2775          */
2776         if (zio->io_vd == NULL && (zio->io_flags & ZIO_FLAG_DONT_PROPAGATE))
2777                 return;
2778 
2779         mutex_enter(&vd->vdev_stat_lock);
2780         if (type == ZIO_TYPE_READ && !vdev_is_dead(vd)) {
2781                 if (zio->io_error == ECKSUM)
2782                         vs->vs_checksum_errors++;
2783                 else
2784                         vs->vs_read_errors++;
2785         }
2786         if (type == ZIO_TYPE_WRITE && !vdev_is_dead(vd))
2787                 vs->vs_write_errors++;
2788         mutex_exit(&vd->vdev_stat_lock);
2789 
2790         if (type == ZIO_TYPE_WRITE && txg != 0 &&
2791             (!(flags & ZIO_FLAG_IO_REPAIR) ||
2792             (flags & ZIO_FLAG_SCAN_THREAD) ||
2793             spa->spa_claiming)) {
2794                 /*
2795                  * This is either a normal write (not a repair), or it's
2796                  * a repair induced by the scrub thread, or it's a repair
2797                  * made by zil_claim() during spa_load() in the first txg.
2798                  * In the normal case, we commit the DTL change in the same
2799                  * txg as the block was born.  In the scrub-induced repair
2800                  * case, we know that scrubs run in first-pass syncing context,
2801                  * so we commit the DTL change in spa_syncing_txg(spa).
2802                  * In the zil_claim() case, we commit in spa_first_txg(spa).
2803                  *
2804                  * We currently do not make DTL entries for failed spontaneous
2805                  * self-healing writes triggered by normal (non-scrubbing)
2806                  * reads, because we have no transactional context in which to
2807                  * do so -- and it's not clear that it'd be desirable anyway.
2808                  */
2809                 if (vd->vdev_ops->vdev_op_leaf) {
2810                         uint64_t commit_txg = txg;
2811                         if (flags & ZIO_FLAG_SCAN_THREAD) {
2812                                 ASSERT(flags & ZIO_FLAG_IO_REPAIR);
2813                                 ASSERT(spa_sync_pass(spa) == 1);
2814                                 vdev_dtl_dirty(vd, DTL_SCRUB, txg, 1);
2815                                 commit_txg = spa_syncing_txg(spa);
2816                         } else if (spa->spa_claiming) {
2817                                 ASSERT(flags & ZIO_FLAG_IO_REPAIR);
2818                                 commit_txg = spa_first_txg(spa);
2819                         }
2820                         ASSERT(commit_txg >= spa_syncing_txg(spa));
2821                         if (vdev_dtl_contains(vd, DTL_MISSING, txg, 1))
2822                                 return;
2823                         for (pvd = vd; pvd != rvd; pvd = pvd->vdev_parent)
2824                                 vdev_dtl_dirty(pvd, DTL_PARTIAL, txg, 1);
2825                         vdev_dirty(vd->vdev_top, VDD_DTL, vd, commit_txg);
2826                 }
2827                 if (vd != rvd)
2828                         vdev_dtl_dirty(vd, DTL_MISSING, txg, 1);
2829         }
2830 }
2831 
2832 /*
2833  * Update the in-core space usage stats for this vdev, its metaslab class,
2834  * and the root vdev.
2835  */
2836 void
2837 vdev_space_update(vdev_t *vd, int64_t alloc_delta, int64_t defer_delta,
2838     int64_t space_delta)
2839 {
2840         int64_t dspace_delta = space_delta;
2841         spa_t *spa = vd->vdev_spa;
2842         vdev_t *rvd = spa->spa_root_vdev;
2843         metaslab_group_t *mg = vd->vdev_mg;
2844         metaslab_class_t *mc = mg ? mg->mg_class : NULL;
2845 
2846         ASSERT(vd == vd->vdev_top);
2847 
2848         /*
2849          * Apply the inverse of the psize-to-asize (ie. RAID-Z) space-expansion
2850          * factor.  We must calculate this here and not at the root vdev
2851          * because the root vdev's psize-to-asize is simply the max of its
2852          * childrens', thus not accurate enough for us.
2853          */
2854         ASSERT((dspace_delta & (SPA_MINBLOCKSIZE-1)) == 0);
2855         ASSERT(vd->vdev_deflate_ratio != 0 || vd->vdev_isl2cache);
2856         dspace_delta = (dspace_delta >> SPA_MINBLOCKSHIFT) *
2857             vd->vdev_deflate_ratio;
2858 
2859         mutex_enter(&vd->vdev_stat_lock);
2860         vd->vdev_stat.vs_alloc += alloc_delta;
2861         vd->vdev_stat.vs_space += space_delta;
2862         vd->vdev_stat.vs_dspace += dspace_delta;
2863         mutex_exit(&vd->vdev_stat_lock);
2864 
2865         if (mc == spa_normal_class(spa)) {
2866                 mutex_enter(&rvd->vdev_stat_lock);
2867                 rvd->vdev_stat.vs_alloc += alloc_delta;
2868                 rvd->vdev_stat.vs_space += space_delta;
2869                 rvd->vdev_stat.vs_dspace += dspace_delta;
2870                 mutex_exit(&rvd->vdev_stat_lock);
2871         }
2872 
2873         if (mc != NULL) {
2874                 ASSERT(rvd == vd->vdev_parent);
2875                 ASSERT(vd->vdev_ms_count != 0);
2876 
2877                 metaslab_class_space_update(mc,
2878                     alloc_delta, defer_delta, space_delta, dspace_delta);
2879         }
2880 }
2881 
2882 /*
2883  * Mark a top-level vdev's config as dirty, placing it on the dirty list
2884  * so that it will be written out next time the vdev configuration is synced.
2885  * If the root vdev is specified (vdev_top == NULL), dirty all top-level vdevs.
2886  */
2887 void
2888 vdev_config_dirty(vdev_t *vd)
2889 {
2890         spa_t *spa = vd->vdev_spa;
2891         vdev_t *rvd = spa->spa_root_vdev;
2892         int c;
2893 
2894         ASSERT(spa_writeable(spa));
2895 
2896         /*
2897          * If this is an aux vdev (as with l2cache and spare devices), then we
2898          * update the vdev config manually and set the sync flag.
2899          */
2900         if (vd->vdev_aux != NULL) {
2901                 spa_aux_vdev_t *sav = vd->vdev_aux;
2902                 nvlist_t **aux;
2903                 uint_t naux;
2904 
2905                 for (c = 0; c < sav->sav_count; c++) {
2906                         if (sav->sav_vdevs[c] == vd)
2907                                 break;
2908                 }
2909 
2910                 if (c == sav->sav_count) {
2911                         /*
2912                          * We're being removed.  There's nothing more to do.
2913                          */
2914                         ASSERT(sav->sav_sync == B_TRUE);
2915                         return;
2916                 }
2917 
2918                 sav->sav_sync = B_TRUE;
2919 
2920                 if (nvlist_lookup_nvlist_array(sav->sav_config,
2921                     ZPOOL_CONFIG_L2CACHE, &aux, &naux) != 0) {
2922                         VERIFY(nvlist_lookup_nvlist_array(sav->sav_config,
2923                             ZPOOL_CONFIG_SPARES, &aux, &naux) == 0);
2924                 }
2925 
2926                 ASSERT(c < naux);
2927 
2928                 /*
2929                  * Setting the nvlist in the middle if the array is a little
2930                  * sketchy, but it will work.
2931                  */
2932                 nvlist_free(aux[c]);
2933                 aux[c] = vdev_config_generate(spa, vd, B_TRUE, 0);
2934 
2935                 return;
2936         }
2937 
2938         /*
2939          * The dirty list is protected by the SCL_CONFIG lock.  The caller
2940          * must either hold SCL_CONFIG as writer, or must be the sync thread
2941          * (which holds SCL_CONFIG as reader).  There's only one sync thread,
2942          * so this is sufficient to ensure mutual exclusion.
2943          */
2944         ASSERT(spa_config_held(spa, SCL_CONFIG, RW_WRITER) ||
2945             (dsl_pool_sync_context(spa_get_dsl(spa)) &&
2946             spa_config_held(spa, SCL_CONFIG, RW_READER)));
2947 
2948         if (vd == rvd) {
2949                 for (c = 0; c < rvd->vdev_children; c++)
2950                         vdev_config_dirty(rvd->vdev_child[c]);
2951         } else {
2952                 ASSERT(vd == vd->vdev_top);
2953 
2954                 if (!list_link_active(&vd->vdev_config_dirty_node) &&
2955                     !vd->vdev_ishole)
2956                         list_insert_head(&spa->spa_config_dirty_list, vd);
2957         }
2958 }
2959 
2960 void
2961 vdev_config_clean(vdev_t *vd)
2962 {
2963         spa_t *spa = vd->vdev_spa;
2964 
2965         ASSERT(spa_config_held(spa, SCL_CONFIG, RW_WRITER) ||
2966             (dsl_pool_sync_context(spa_get_dsl(spa)) &&
2967             spa_config_held(spa, SCL_CONFIG, RW_READER)));
2968 
2969         ASSERT(list_link_active(&vd->vdev_config_dirty_node));
2970         list_remove(&spa->spa_config_dirty_list, vd);
2971 }
2972 
2973 /*
2974  * Mark a top-level vdev's state as dirty, so that the next pass of
2975  * spa_sync() can convert this into vdev_config_dirty().  We distinguish
2976  * the state changes from larger config changes because they require
2977  * much less locking, and are often needed for administrative actions.
2978  */
2979 void
2980 vdev_state_dirty(vdev_t *vd)
2981 {
2982         spa_t *spa = vd->vdev_spa;
2983 
2984         ASSERT(spa_writeable(spa));
2985         ASSERT(vd == vd->vdev_top);
2986 
2987         /*
2988          * The state list is protected by the SCL_STATE lock.  The caller
2989          * must either hold SCL_STATE as writer, or must be the sync thread
2990          * (which holds SCL_STATE as reader).  There's only one sync thread,
2991          * so this is sufficient to ensure mutual exclusion.
2992          */
2993         ASSERT(spa_config_held(spa, SCL_STATE, RW_WRITER) ||
2994             (dsl_pool_sync_context(spa_get_dsl(spa)) &&
2995             spa_config_held(spa, SCL_STATE, RW_READER)));
2996 
2997         if (!list_link_active(&vd->vdev_state_dirty_node) && !vd->vdev_ishole)
2998                 list_insert_head(&spa->spa_state_dirty_list, vd);
2999 }
3000 
3001 void
3002 vdev_state_clean(vdev_t *vd)
3003 {
3004         spa_t *spa = vd->vdev_spa;
3005 
3006         ASSERT(spa_config_held(spa, SCL_STATE, RW_WRITER) ||
3007             (dsl_pool_sync_context(spa_get_dsl(spa)) &&
3008             spa_config_held(spa, SCL_STATE, RW_READER)));
3009 
3010         ASSERT(list_link_active(&vd->vdev_state_dirty_node));
3011         list_remove(&spa->spa_state_dirty_list, vd);
3012 }
3013 
3014 /*
3015  * Propagate vdev state up from children to parent.
3016  */
3017 void
3018 vdev_propagate_state(vdev_t *vd)
3019 {
3020         spa_t *spa = vd->vdev_spa;
3021         vdev_t *rvd = spa->spa_root_vdev;
3022         int degraded = 0, faulted = 0;
3023         int corrupted = 0;
3024         vdev_t *child;
3025 
3026         if (vd->vdev_children > 0) {
3027                 for (int c = 0; c < vd->vdev_children; c++) {
3028                         child = vd->vdev_child[c];
3029 
3030                         /*
3031                          * Don't factor holes into the decision.
3032                          */
3033                         if (child->vdev_ishole)
3034                                 continue;
3035 
3036                         if (!vdev_readable(child) ||
3037                             (!vdev_writeable(child) && spa_writeable(spa))) {
3038                                 /*
3039                                  * Root special: if there is a top-level log
3040                                  * device, treat the root vdev as if it were
3041                                  * degraded.
3042                                  */
3043                                 if (child->vdev_islog && vd == rvd)
3044                                         degraded++;
3045                                 else
3046                                         faulted++;
3047                         } else if (child->vdev_state <= VDEV_STATE_DEGRADED) {
3048                                 degraded++;
3049                         }
3050 
3051                         if (child->vdev_stat.vs_aux == VDEV_AUX_CORRUPT_DATA)
3052                                 corrupted++;
3053                 }
3054 
3055                 vd->vdev_ops->vdev_op_state_change(vd, faulted, degraded);
3056 
3057                 /*
3058                  * Root special: if there is a top-level vdev that cannot be
3059                  * opened due to corrupted metadata, then propagate the root
3060                  * vdev's aux state as 'corrupt' rather than 'insufficient
3061                  * replicas'.
3062                  */
3063                 if (corrupted && vd == rvd &&
3064                     rvd->vdev_state == VDEV_STATE_CANT_OPEN)
3065                         vdev_set_state(rvd, B_FALSE, VDEV_STATE_CANT_OPEN,
3066                             VDEV_AUX_CORRUPT_DATA);
3067         }
3068 
3069         if (vd->vdev_parent)
3070                 vdev_propagate_state(vd->vdev_parent);
3071 }
3072 
3073 /*
3074  * Set a vdev's state.  If this is during an open, we don't update the parent
3075  * state, because we're in the process of opening children depth-first.
3076  * Otherwise, we propagate the change to the parent.
3077  *
3078  * If this routine places a device in a faulted state, an appropriate ereport is
3079  * generated.
3080  */
3081 void
3082 vdev_set_state(vdev_t *vd, boolean_t isopen, vdev_state_t state, vdev_aux_t aux)
3083 {
3084         uint64_t save_state;
3085         spa_t *spa = vd->vdev_spa;
3086 
3087         if (state == vd->vdev_state) {
3088                 vd->vdev_stat.vs_aux = aux;
3089                 return;
3090         }
3091 
3092         save_state = vd->vdev_state;
3093 
3094         vd->vdev_state = state;
3095         vd->vdev_stat.vs_aux = aux;
3096 
3097         /*
3098          * If we are setting the vdev state to anything but an open state, then
3099          * always close the underlying device unless the device has requested
3100          * a delayed close (i.e. we're about to remove or fault the device).
3101          * Otherwise, we keep accessible but invalid devices open forever.
3102          * We don't call vdev_close() itself, because that implies some extra
3103          * checks (offline, etc) that we don't want here.  This is limited to
3104          * leaf devices, because otherwise closing the device will affect other
3105          * children.
3106          */
3107         if (!vd->vdev_delayed_close && vdev_is_dead(vd) &&
3108             vd->vdev_ops->vdev_op_leaf)
3109                 vd->vdev_ops->vdev_op_close(vd);
3110 
3111         /*
3112          * If we have brought this vdev back into service, we need
3113          * to notify fmd so that it can gracefully repair any outstanding
3114          * cases due to a missing device.  We do this in all cases, even those
3115          * that probably don't correlate to a repaired fault.  This is sure to
3116          * catch all cases, and we let the zfs-retire agent sort it out.  If
3117          * this is a transient state it's OK, as the retire agent will
3118          * double-check the state of the vdev before repairing it.
3119          */
3120         if (state == VDEV_STATE_HEALTHY && vd->vdev_ops->vdev_op_leaf &&
3121             vd->vdev_prevstate != state)
3122                 zfs_post_state_change(spa, vd);
3123 
3124         if (vd->vdev_removed &&
3125             state == VDEV_STATE_CANT_OPEN &&
3126             (aux == VDEV_AUX_OPEN_FAILED || vd->vdev_checkremove)) {
3127                 /*
3128                  * If the previous state is set to VDEV_STATE_REMOVED, then this
3129                  * device was previously marked removed and someone attempted to
3130                  * reopen it.  If this failed due to a nonexistent device, then
3131                  * keep the device in the REMOVED state.  We also let this be if
3132                  * it is one of our special test online cases, which is only
3133                  * attempting to online the device and shouldn't generate an FMA
3134                  * fault.
3135                  */
3136                 vd->vdev_state = VDEV_STATE_REMOVED;
3137                 vd->vdev_stat.vs_aux = VDEV_AUX_NONE;
3138         } else if (state == VDEV_STATE_REMOVED) {
3139                 vd->vdev_removed = B_TRUE;
3140         } else if (state == VDEV_STATE_CANT_OPEN) {
3141                 /*
3142                  * If we fail to open a vdev during an import or recovery, we
3143                  * mark it as "not available", which signifies that it was
3144                  * never there to begin with.  Failure to open such a device
3145                  * is not considered an error.
3146                  */
3147                 if ((spa_load_state(spa) == SPA_LOAD_IMPORT ||
3148                     spa_load_state(spa) == SPA_LOAD_RECOVER) &&
3149                     vd->vdev_ops->vdev_op_leaf)
3150                         vd->vdev_not_present = 1;
3151 
3152                 /*
3153                  * Post the appropriate ereport.  If the 'prevstate' field is
3154                  * set to something other than VDEV_STATE_UNKNOWN, it indicates
3155                  * that this is part of a vdev_reopen().  In this case, we don't
3156                  * want to post the ereport if the device was already in the
3157                  * CANT_OPEN state beforehand.
3158                  *
3159                  * If the 'checkremove' flag is set, then this is an attempt to
3160                  * online the device in response to an insertion event.  If we
3161                  * hit this case, then we have detected an insertion event for a
3162                  * faulted or offline device that wasn't in the removed state.
3163                  * In this scenario, we don't post an ereport because we are
3164                  * about to replace the device, or attempt an online with
3165                  * vdev_forcefault, which will generate the fault for us.
3166                  */
3167                 if ((vd->vdev_prevstate != state || vd->vdev_forcefault) &&
3168                     !vd->vdev_not_present && !vd->vdev_checkremove &&
3169                     vd != spa->spa_root_vdev) {
3170                         const char *class;
3171 
3172                         switch (aux) {
3173                         case VDEV_AUX_OPEN_FAILED:
3174                                 class = FM_EREPORT_ZFS_DEVICE_OPEN_FAILED;
3175                                 break;
3176                         case VDEV_AUX_CORRUPT_DATA:
3177                                 class = FM_EREPORT_ZFS_DEVICE_CORRUPT_DATA;
3178                                 break;
3179                         case VDEV_AUX_NO_REPLICAS:
3180                                 class = FM_EREPORT_ZFS_DEVICE_NO_REPLICAS;
3181                                 break;
3182                         case VDEV_AUX_BAD_GUID_SUM:
3183                                 class = FM_EREPORT_ZFS_DEVICE_BAD_GUID_SUM;
3184                                 break;
3185                         case VDEV_AUX_TOO_SMALL:
3186                                 class = FM_EREPORT_ZFS_DEVICE_TOO_SMALL;
3187                                 break;
3188                         case VDEV_AUX_BAD_LABEL:
3189                                 class = FM_EREPORT_ZFS_DEVICE_BAD_LABEL;
3190                                 break;
3191                         default:
3192                                 class = FM_EREPORT_ZFS_DEVICE_UNKNOWN;
3193                         }
3194 
3195                         zfs_ereport_post(class, spa, vd, NULL, save_state, 0);
3196                 }
3197 
3198                 /* Erase any notion of persistent removed state */
3199                 vd->vdev_removed = B_FALSE;
3200         } else {
3201                 vd->vdev_removed = B_FALSE;
3202         }
3203 
3204         if (!isopen && vd->vdev_parent)
3205                 vdev_propagate_state(vd->vdev_parent);
3206 }
3207 
3208 /*
3209  * Check the vdev configuration to ensure that it's capable of supporting
3210  * a root pool. Currently, we do not support RAID-Z or partial configuration.
3211  * In addition, only a single top-level vdev is allowed and none of the leaves
3212  * can be wholedisks.
3213  */
3214 boolean_t
3215 vdev_is_bootable(vdev_t *vd)
3216 {
3217         if (!vd->vdev_ops->vdev_op_leaf) {
3218                 char *vdev_type = vd->vdev_ops->vdev_op_type;
3219 
3220                 if (strcmp(vdev_type, VDEV_TYPE_ROOT) == 0 &&
3221                     vd->vdev_children > 1) {
3222                         return (B_FALSE);
3223                 } else if (strcmp(vdev_type, VDEV_TYPE_RAIDZ) == 0 ||
3224                     strcmp(vdev_type, VDEV_TYPE_MISSING) == 0) {
3225                         return (B_FALSE);
3226                 }
3227         }
3228 
3229         for (int c = 0; c < vd->vdev_children; c++) {
3230                 if (!vdev_is_bootable(vd->vdev_child[c]))
3231                         return (B_FALSE);
3232         }
3233         return (B_TRUE);
3234 }
3235 
3236 /*
3237  * Load the state from the original vdev tree (ovd) which
3238  * we've retrieved from the MOS config object. If the original
3239  * vdev was offline or faulted then we transfer that state to the
3240  * device in the current vdev tree (nvd).
3241  */
3242 void
3243 vdev_load_log_state(vdev_t *nvd, vdev_t *ovd)
3244 {
3245         spa_t *spa = nvd->vdev_spa;
3246 
3247         ASSERT(nvd->vdev_top->vdev_islog);
3248         ASSERT(spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
3249         ASSERT3U(nvd->vdev_guid, ==, ovd->vdev_guid);
3250 
3251         for (int c = 0; c < nvd->vdev_children; c++)
3252                 vdev_load_log_state(nvd->vdev_child[c], ovd->vdev_child[c]);
3253 
3254         if (nvd->vdev_ops->vdev_op_leaf) {
3255                 /*
3256                  * Restore the persistent vdev state
3257                  */
3258                 nvd->vdev_offline = ovd->vdev_offline;
3259                 nvd->vdev_faulted = ovd->vdev_faulted;
3260                 nvd->vdev_degraded = ovd->vdev_degraded;
3261                 nvd->vdev_removed = ovd->vdev_removed;
3262         }
3263 }
3264 
3265 /*
3266  * Determine if a log device has valid content.  If the vdev was
3267  * removed or faulted in the MOS config then we know that
3268  * the content on the log device has already been written to the pool.
3269  */
3270 boolean_t
3271 vdev_log_state_valid(vdev_t *vd)
3272 {
3273         if (vd->vdev_ops->vdev_op_leaf && !vd->vdev_faulted &&
3274             !vd->vdev_removed)
3275                 return (B_TRUE);
3276 
3277         for (int c = 0; c < vd->vdev_children; c++)
3278                 if (vdev_log_state_valid(vd->vdev_child[c]))
3279                         return (B_TRUE);
3280 
3281         return (B_FALSE);
3282 }
3283 
3284 /*
3285  * Expand a vdev if possible.
3286  */
3287 void
3288 vdev_expand(vdev_t *vd, uint64_t txg)
3289 {
3290         ASSERT(vd->vdev_top == vd);
3291         ASSERT(spa_config_held(vd->vdev_spa, SCL_ALL, RW_WRITER) == SCL_ALL);
3292 
3293         if ((vd->vdev_asize >> vd->vdev_ms_shift) > vd->vdev_ms_count) {
3294                 VERIFY(vdev_metaslab_init(vd, txg) == 0);
3295                 vdev_config_dirty(vd);
3296         }
3297 }
3298 
3299 /*
3300  * Split a vdev.
3301  */
3302 void
3303 vdev_split(vdev_t *vd)
3304 {
3305         vdev_t *cvd, *pvd = vd->vdev_parent;
3306 
3307         vdev_remove_child(pvd, vd);
3308         vdev_compact_children(pvd);
3309 
3310         cvd = pvd->vdev_child[0];
3311         if (pvd->vdev_children == 1) {
3312                 vdev_remove_parent(cvd);
3313                 cvd->vdev_splitting = B_TRUE;
3314         }
3315         vdev_propagate_state(cvd);
3316 }
3317 
3318 void
3319 vdev_deadman(vdev_t *vd)
3320 {
3321         for (int c = 0; c < vd->vdev_children; c++) {
3322                 vdev_t *cvd = vd->vdev_child[c];
3323 
3324                 vdev_deadman(cvd);
3325         }
3326 
3327         if (vd->vdev_ops->vdev_op_leaf) {
3328                 vdev_queue_t *vq = &vd->vdev_queue;
3329 
3330                 mutex_enter(&vq->vq_lock);
3331                 if (avl_numnodes(&vq->vq_active_tree) > 0) {
3332                         spa_t *spa = vd->vdev_spa;
3333                         zio_t *fio;
3334                         uint64_t delta;
3335 
3336                         /*
3337                          * Look at the head of all the pending queues,
3338                          * if any I/O has been outstanding for longer than
3339                          * the spa_deadman_synctime we panic the system.
3340                          */
3341                         fio = avl_first(&vq->vq_active_tree);
3342                         delta = gethrtime() - fio->io_timestamp;
3343                         if (delta > spa_deadman_synctime(spa)) {
3344                                 zfs_dbgmsg("SLOW IO: zio timestamp %lluns, "
3345                                     "delta %lluns, last io %lluns",
3346                                     fio->io_timestamp, delta,
3347                                     vq->vq_io_complete_ts);
3348                                 fm_panic("I/O to pool '%s' appears to be "
3349                                     "hung.", spa_name(spa));
3350                         }
3351                 }
3352                 mutex_exit(&vq->vq_lock);
3353         }
3354 }