1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  23  * Copyright (c) 2012 by Delphix. All rights reserved.
  24  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  25  */
  26 
  27 #include <sys/zfs_context.h>
  28 #include <sys/spa_impl.h>
  29 #include <sys/zio.h>
  30 #include <sys/zio_checksum.h>
  31 #include <sys/zio_compress.h>
  32 #include <sys/dmu.h>
  33 #include <sys/dmu_tx.h>
  34 #include <sys/zap.h>
  35 #include <sys/zil.h>
  36 #include <sys/vdev_impl.h>
  37 #include <sys/metaslab.h>
  38 #include <sys/uberblock_impl.h>
  39 #include <sys/txg.h>
  40 #include <sys/avl.h>
  41 #include <sys/unique.h>
  42 #include <sys/dsl_pool.h>
  43 #include <sys/dsl_dir.h>
  44 #include <sys/dsl_prop.h>
  45 #include <sys/dsl_scan.h>
  46 #include <sys/fs/zfs.h>
  47 #include <sys/metaslab_impl.h>
  48 #include <sys/arc.h>
  49 #include <sys/ddt.h>
  50 #include "zfs_prop.h"
  51 #include "zfeature_common.h"
  52 
  53 /*
  54  * SPA locking
  55  *
  56  * There are four basic locks for managing spa_t structures:
  57  *
  58  * spa_namespace_lock (global mutex)
  59  *
  60  *      This lock must be acquired to do any of the following:
  61  *
  62  *              - Lookup a spa_t by name
  63  *              - Add or remove a spa_t from the namespace
  64  *              - Increase spa_refcount from non-zero
  65  *              - Check if spa_refcount is zero
  66  *              - Rename a spa_t
  67  *              - add/remove/attach/detach devices
  68  *              - Held for the duration of create/destroy/import/export
  69  *
  70  *      It does not need to handle recursion.  A create or destroy may
  71  *      reference objects (files or zvols) in other pools, but by
  72  *      definition they must have an existing reference, and will never need
  73  *      to lookup a spa_t by name.
  74  *
  75  * spa_refcount (per-spa refcount_t protected by mutex)
  76  *
  77  *      This reference count keep track of any active users of the spa_t.  The
  78  *      spa_t cannot be destroyed or freed while this is non-zero.  Internally,
  79  *      the refcount is never really 'zero' - opening a pool implicitly keeps
  80  *      some references in the DMU.  Internally we check against spa_minref, but
  81  *      present the image of a zero/non-zero value to consumers.
  82  *
  83  * spa_config_lock[] (per-spa array of rwlocks)
  84  *
  85  *      This protects the spa_t from config changes, and must be held in
  86  *      the following circumstances:
  87  *
  88  *              - RW_READER to perform I/O to the spa
  89  *              - RW_WRITER to change the vdev config
  90  *
  91  * The locking order is fairly straightforward:
  92  *
  93  *              spa_namespace_lock      ->   spa_refcount
  94  *
  95  *      The namespace lock must be acquired to increase the refcount from 0
  96  *      or to check if it is zero.
  97  *
  98  *              spa_refcount            ->   spa_config_lock[]
  99  *
 100  *      There must be at least one valid reference on the spa_t to acquire
 101  *      the config lock.
 102  *
 103  *              spa_namespace_lock      ->   spa_config_lock[]
 104  *
 105  *      The namespace lock must always be taken before the config lock.
 106  *
 107  *
 108  * The spa_namespace_lock can be acquired directly and is globally visible.
 109  *
 110  * The namespace is manipulated using the following functions, all of which
 111  * require the spa_namespace_lock to be held.
 112  *
 113  *      spa_lookup()            Lookup a spa_t by name.
 114  *
 115  *      spa_add()               Create a new spa_t in the namespace.
 116  *
 117  *      spa_remove()            Remove a spa_t from the namespace.  This also
 118  *                              frees up any memory associated with the spa_t.
 119  *
 120  *      spa_next()              Returns the next spa_t in the system, or the
 121  *                              first if NULL is passed.
 122  *
 123  *      spa_evict_all()         Shutdown and remove all spa_t structures in
 124  *                              the system.
 125  *
 126  *      spa_guid_exists()       Determine whether a pool/device guid exists.
 127  *
 128  * The spa_refcount is manipulated using the following functions:
 129  *
 130  *      spa_open_ref()          Adds a reference to the given spa_t.  Must be
 131  *                              called with spa_namespace_lock held if the
 132  *                              refcount is currently zero.
 133  *
 134  *      spa_close()             Remove a reference from the spa_t.  This will
 135  *                              not free the spa_t or remove it from the
 136  *                              namespace.  No locking is required.
 137  *
 138  *      spa_refcount_zero()     Returns true if the refcount is currently
 139  *                              zero.  Must be called with spa_namespace_lock
 140  *                              held.
 141  *
 142  * The spa_config_lock[] is an array of rwlocks, ordered as follows:
 143  * SCL_CONFIG > SCL_STATE > SCL_ALLOC > SCL_ZIO > SCL_FREE > SCL_VDEV.
 144  * spa_config_lock[] is manipulated with spa_config_{enter,exit,held}().
 145  *
 146  * To read the configuration, it suffices to hold one of these locks as reader.
 147  * To modify the configuration, you must hold all locks as writer.  To modify
 148  * vdev state without altering the vdev tree's topology (e.g. online/offline),
 149  * you must hold SCL_STATE and SCL_ZIO as writer.
 150  *
 151  * We use these distinct config locks to avoid recursive lock entry.
 152  * For example, spa_sync() (which holds SCL_CONFIG as reader) induces
 153  * block allocations (SCL_ALLOC), which may require reading space maps
 154  * from disk (dmu_read() -> zio_read() -> SCL_ZIO).
 155  *
 156  * The spa config locks cannot be normal rwlocks because we need the
 157  * ability to hand off ownership.  For example, SCL_ZIO is acquired
 158  * by the issuing thread and later released by an interrupt thread.
 159  * They do, however, obey the usual write-wanted semantics to prevent
 160  * writer (i.e. system administrator) starvation.
 161  *
 162  * The lock acquisition rules are as follows:
 163  *
 164  * SCL_CONFIG
 165  *      Protects changes to the vdev tree topology, such as vdev
 166  *      add/remove/attach/detach.  Protects the dirty config list
 167  *      (spa_config_dirty_list) and the set of spares and l2arc devices.
 168  *
 169  * SCL_STATE
 170  *      Protects changes to pool state and vdev state, such as vdev
 171  *      online/offline/fault/degrade/clear.  Protects the dirty state list
 172  *      (spa_state_dirty_list) and global pool state (spa_state).
 173  *
 174  * SCL_ALLOC
 175  *      Protects changes to metaslab groups and classes.
 176  *      Held as reader by metaslab_alloc() and metaslab_claim().
 177  *
 178  * SCL_ZIO
 179  *      Held by bp-level zios (those which have no io_vd upon entry)
 180  *      to prevent changes to the vdev tree.  The bp-level zio implicitly
 181  *      protects all of its vdev child zios, which do not hold SCL_ZIO.
 182  *
 183  * SCL_FREE
 184  *      Protects changes to metaslab groups and classes.
 185  *      Held as reader by metaslab_free().  SCL_FREE is distinct from
 186  *      SCL_ALLOC, and lower than SCL_ZIO, so that we can safely free
 187  *      blocks in zio_done() while another i/o that holds either
 188  *      SCL_ALLOC or SCL_ZIO is waiting for this i/o to complete.
 189  *
 190  * SCL_VDEV
 191  *      Held as reader to prevent changes to the vdev tree during trivial
 192  *      inquiries such as bp_get_dsize().  SCL_VDEV is distinct from the
 193  *      other locks, and lower than all of them, to ensure that it's safe
 194  *      to acquire regardless of caller context.
 195  *
 196  * In addition, the following rules apply:
 197  *
 198  * (a)  spa_props_lock protects pool properties, spa_config and spa_config_list.
 199  *      The lock ordering is SCL_CONFIG > spa_props_lock.
 200  *
 201  * (b)  I/O operations on leaf vdevs.  For any zio operation that takes
 202  *      an explicit vdev_t argument -- such as zio_ioctl(), zio_read_phys(),
 203  *      or zio_write_phys() -- the caller must ensure that the config cannot
 204  *      cannot change in the interim, and that the vdev cannot be reopened.
 205  *      SCL_STATE as reader suffices for both.
 206  *
 207  * The vdev configuration is protected by spa_vdev_enter() / spa_vdev_exit().
 208  *
 209  *      spa_vdev_enter()        Acquire the namespace lock and the config lock
 210  *                              for writing.
 211  *
 212  *      spa_vdev_exit()         Release the config lock, wait for all I/O
 213  *                              to complete, sync the updated configs to the
 214  *                              cache, and release the namespace lock.
 215  *
 216  * vdev state is protected by spa_vdev_state_enter() / spa_vdev_state_exit().
 217  * Like spa_vdev_enter/exit, these are convenience wrappers -- the actual
 218  * locking is, always, based on spa_namespace_lock and spa_config_lock[].
 219  *
 220  * spa_rename() is also implemented within this file since it requires
 221  * manipulation of the namespace.
 222  */
 223 
 224 static avl_tree_t spa_namespace_avl;
 225 kmutex_t spa_namespace_lock;
 226 static kcondvar_t spa_namespace_cv;
 227 static int spa_active_count;
 228 int spa_max_replication_override = SPA_DVAS_PER_BP;
 229 
 230 static kmutex_t spa_spare_lock;
 231 static avl_tree_t spa_spare_avl;
 232 static kmutex_t spa_l2cache_lock;
 233 static avl_tree_t spa_l2cache_avl;
 234 
 235 kmem_cache_t *spa_buffer_pool;
 236 int spa_mode_global;
 237 
 238 #ifdef ZFS_DEBUG
 239 /* Everything except dprintf is on by default in debug builds */
 240 int zfs_flags = ~ZFS_DEBUG_DPRINTF;
 241 #else
 242 int zfs_flags = 0;
 243 #endif
 244 
 245 /*
 246  * zfs_recover can be set to nonzero to attempt to recover from
 247  * otherwise-fatal errors, typically caused by on-disk corruption.  When
 248  * set, calls to zfs_panic_recover() will turn into warning messages.
 249  */
 250 int zfs_recover = 0;
 251 
 252 
 253 /*
 254  * ==========================================================================
 255  * SPA config locking
 256  * ==========================================================================
 257  */
 258 static void
 259 spa_config_lock_init(spa_t *spa)
 260 {
 261         for (int i = 0; i < SCL_LOCKS; i++) {
 262                 spa_config_lock_t *scl = &spa->spa_config_lock[i];
 263                 mutex_init(&scl->scl_lock, NULL, MUTEX_DEFAULT, NULL);
 264                 cv_init(&scl->scl_cv, NULL, CV_DEFAULT, NULL);
 265                 refcount_create(&scl->scl_count);
 266                 scl->scl_writer = NULL;
 267                 scl->scl_write_wanted = 0;
 268         }
 269 }
 270 
 271 static void
 272 spa_config_lock_destroy(spa_t *spa)
 273 {
 274         for (int i = 0; i < SCL_LOCKS; i++) {
 275                 spa_config_lock_t *scl = &spa->spa_config_lock[i];
 276                 mutex_destroy(&scl->scl_lock);
 277                 cv_destroy(&scl->scl_cv);
 278                 refcount_destroy(&scl->scl_count);
 279                 ASSERT(scl->scl_writer == NULL);
 280                 ASSERT(scl->scl_write_wanted == 0);
 281         }
 282 }
 283 
 284 int
 285 spa_config_tryenter(spa_t *spa, int locks, void *tag, krw_t rw)
 286 {
 287         for (int i = 0; i < SCL_LOCKS; i++) {
 288                 spa_config_lock_t *scl = &spa->spa_config_lock[i];
 289                 if (!(locks & (1 << i)))
 290                         continue;
 291                 mutex_enter(&scl->scl_lock);
 292                 if (rw == RW_READER) {
 293                         if (scl->scl_writer || scl->scl_write_wanted) {
 294                                 mutex_exit(&scl->scl_lock);
 295                                 spa_config_exit(spa, locks ^ (1 << i), tag);
 296                                 return (0);
 297                         }
 298                 } else {
 299                         ASSERT(scl->scl_writer != curthread);
 300                         if (!refcount_is_zero(&scl->scl_count)) {
 301                                 mutex_exit(&scl->scl_lock);
 302                                 spa_config_exit(spa, locks ^ (1 << i), tag);
 303                                 return (0);
 304                         }
 305                         scl->scl_writer = curthread;
 306                 }
 307                 (void) refcount_add(&scl->scl_count, tag);
 308                 mutex_exit(&scl->scl_lock);
 309         }
 310         return (1);
 311 }
 312 
 313 void
 314 spa_config_enter(spa_t *spa, int locks, void *tag, krw_t rw)
 315 {
 316         int wlocks_held = 0;
 317 
 318         for (int i = 0; i < SCL_LOCKS; i++) {
 319                 spa_config_lock_t *scl = &spa->spa_config_lock[i];
 320                 if (scl->scl_writer == curthread)
 321                         wlocks_held |= (1 << i);
 322                 if (!(locks & (1 << i)))
 323                         continue;
 324                 mutex_enter(&scl->scl_lock);
 325                 if (rw == RW_READER) {
 326                         while (scl->scl_writer || scl->scl_write_wanted) {
 327                                 cv_wait(&scl->scl_cv, &scl->scl_lock);
 328                         }
 329                 } else {
 330                         ASSERT(scl->scl_writer != curthread);
 331                         while (!refcount_is_zero(&scl->scl_count)) {
 332                                 scl->scl_write_wanted++;
 333                                 cv_wait(&scl->scl_cv, &scl->scl_lock);
 334                                 scl->scl_write_wanted--;
 335                         }
 336                         scl->scl_writer = curthread;
 337                 }
 338                 (void) refcount_add(&scl->scl_count, tag);
 339                 mutex_exit(&scl->scl_lock);
 340         }
 341         ASSERT(wlocks_held <= locks);
 342 }
 343 
 344 void
 345 spa_config_exit(spa_t *spa, int locks, void *tag)
 346 {
 347         for (int i = SCL_LOCKS - 1; i >= 0; i--) {
 348                 spa_config_lock_t *scl = &spa->spa_config_lock[i];
 349                 if (!(locks & (1 << i)))
 350                         continue;
 351                 mutex_enter(&scl->scl_lock);
 352                 ASSERT(!refcount_is_zero(&scl->scl_count));
 353                 if (refcount_remove(&scl->scl_count, tag) == 0) {
 354                         ASSERT(scl->scl_writer == NULL ||
 355                             scl->scl_writer == curthread);
 356                         scl->scl_writer = NULL;      /* OK in either case */
 357                         cv_broadcast(&scl->scl_cv);
 358                 }
 359                 mutex_exit(&scl->scl_lock);
 360         }
 361 }
 362 
 363 int
 364 spa_config_held(spa_t *spa, int locks, krw_t rw)
 365 {
 366         int locks_held = 0;
 367 
 368         for (int i = 0; i < SCL_LOCKS; i++) {
 369                 spa_config_lock_t *scl = &spa->spa_config_lock[i];
 370                 if (!(locks & (1 << i)))
 371                         continue;
 372                 if ((rw == RW_READER && !refcount_is_zero(&scl->scl_count)) ||
 373                     (rw == RW_WRITER && scl->scl_writer == curthread))
 374                         locks_held |= 1 << i;
 375         }
 376 
 377         return (locks_held);
 378 }
 379 
 380 /*
 381  * ==========================================================================
 382  * SPA namespace functions
 383  * ==========================================================================
 384  */
 385 
 386 /*
 387  * Lookup the named spa_t in the AVL tree.  The spa_namespace_lock must be held.
 388  * Returns NULL if no matching spa_t is found.
 389  */
 390 spa_t *
 391 spa_lookup(const char *name)
 392 {
 393         static spa_t search;    /* spa_t is large; don't allocate on stack */
 394         spa_t *spa;
 395         avl_index_t where;
 396         char c;
 397         char *cp;
 398 
 399         ASSERT(MUTEX_HELD(&spa_namespace_lock));
 400 
 401         /*
 402          * If it's a full dataset name, figure out the pool name and
 403          * just use that.
 404          */
 405         cp = strpbrk(name, "/@");
 406         if (cp) {
 407                 c = *cp;
 408                 *cp = '\0';
 409         }
 410 
 411         (void) strlcpy(search.spa_name, name, sizeof (search.spa_name));
 412         spa = avl_find(&spa_namespace_avl, &search, &where);
 413 
 414         if (cp)
 415                 *cp = c;
 416 
 417         return (spa);
 418 }
 419 
 420 /*
 421  * Create an uninitialized spa_t with the given name.  Requires
 422  * spa_namespace_lock.  The caller must ensure that the spa_t doesn't already
 423  * exist by calling spa_lookup() first.
 424  */
 425 spa_t *
 426 spa_add(const char *name, nvlist_t *config, const char *altroot)
 427 {
 428         spa_t *spa;
 429         spa_config_dirent_t *dp;
 430 
 431         ASSERT(MUTEX_HELD(&spa_namespace_lock));
 432 
 433         spa = kmem_zalloc(sizeof (spa_t), KM_SLEEP);
 434 
 435         mutex_init(&spa->spa_async_lock, NULL, MUTEX_DEFAULT, NULL);
 436         mutex_init(&spa->spa_errlist_lock, NULL, MUTEX_DEFAULT, NULL);
 437         mutex_init(&spa->spa_errlog_lock, NULL, MUTEX_DEFAULT, NULL);
 438         mutex_init(&spa->spa_history_lock, NULL, MUTEX_DEFAULT, NULL);
 439         mutex_init(&spa->spa_proc_lock, NULL, MUTEX_DEFAULT, NULL);
 440         mutex_init(&spa->spa_props_lock, NULL, MUTEX_DEFAULT, NULL);
 441         mutex_init(&spa->spa_scrub_lock, NULL, MUTEX_DEFAULT, NULL);
 442         mutex_init(&spa->spa_suspend_lock, NULL, MUTEX_DEFAULT, NULL);
 443         mutex_init(&spa->spa_vdev_top_lock, NULL, MUTEX_DEFAULT, NULL);
 444 
 445         cv_init(&spa->spa_async_cv, NULL, CV_DEFAULT, NULL);
 446         cv_init(&spa->spa_proc_cv, NULL, CV_DEFAULT, NULL);
 447         cv_init(&spa->spa_scrub_io_cv, NULL, CV_DEFAULT, NULL);
 448         cv_init(&spa->spa_suspend_cv, NULL, CV_DEFAULT, NULL);
 449 
 450         for (int t = 0; t < TXG_SIZE; t++)
 451                 bplist_create(&spa->spa_free_bplist[t]);
 452 
 453         (void) strlcpy(spa->spa_name, name, sizeof (spa->spa_name));
 454         spa->spa_state = POOL_STATE_UNINITIALIZED;
 455         spa->spa_freeze_txg = UINT64_MAX;
 456         spa->spa_final_txg = UINT64_MAX;
 457         spa->spa_load_max_txg = UINT64_MAX;
 458         spa->spa_proc = &p0;
 459         spa->spa_proc_state = SPA_PROC_NONE;
 460 
 461         refcount_create(&spa->spa_refcount);
 462         spa_config_lock_init(spa);
 463 
 464         avl_add(&spa_namespace_avl, spa);
 465 
 466         /*
 467          * Set the alternate root, if there is one.
 468          */
 469         if (altroot) {
 470                 spa->spa_root = spa_strdup(altroot);
 471                 spa_active_count++;
 472         }
 473 
 474         /*
 475          * Every pool starts with the default cachefile
 476          */
 477         list_create(&spa->spa_config_list, sizeof (spa_config_dirent_t),
 478             offsetof(spa_config_dirent_t, scd_link));
 479 
 480         dp = kmem_zalloc(sizeof (spa_config_dirent_t), KM_SLEEP);
 481         dp->scd_path = altroot ? NULL : spa_strdup(spa_config_path);
 482         list_insert_head(&spa->spa_config_list, dp);
 483 
 484         VERIFY(nvlist_alloc(&spa->spa_load_info, NV_UNIQUE_NAME,
 485             KM_SLEEP) == 0);
 486 
 487         if (config != NULL) {
 488                 nvlist_t *features;
 489 
 490                 if (nvlist_lookup_nvlist(config, ZPOOL_CONFIG_FEATURES_FOR_READ,
 491                     &features) == 0) {
 492                         VERIFY(nvlist_dup(features, &spa->spa_label_features,
 493                             0) == 0);
 494                 }
 495 
 496                 VERIFY(nvlist_dup(config, &spa->spa_config, 0) == 0);
 497         }
 498 
 499         if (spa->spa_label_features == NULL) {
 500                 VERIFY(nvlist_alloc(&spa->spa_label_features, NV_UNIQUE_NAME,
 501                     KM_SLEEP) == 0);
 502         }
 503 
 504         return (spa);
 505 }
 506 
 507 /*
 508  * Removes a spa_t from the namespace, freeing up any memory used.  Requires
 509  * spa_namespace_lock.  This is called only after the spa_t has been closed and
 510  * deactivated.
 511  */
 512 void
 513 spa_remove(spa_t *spa)
 514 {
 515         spa_config_dirent_t *dp;
 516 
 517         ASSERT(MUTEX_HELD(&spa_namespace_lock));
 518         ASSERT(spa->spa_state == POOL_STATE_UNINITIALIZED);
 519 
 520         nvlist_free(spa->spa_config_splitting);
 521 
 522         avl_remove(&spa_namespace_avl, spa);
 523         cv_broadcast(&spa_namespace_cv);
 524 
 525         if (spa->spa_root) {
 526                 spa_strfree(spa->spa_root);
 527                 spa_active_count--;
 528         }
 529 
 530         while ((dp = list_head(&spa->spa_config_list)) != NULL) {
 531                 list_remove(&spa->spa_config_list, dp);
 532                 if (dp->scd_path != NULL)
 533                         spa_strfree(dp->scd_path);
 534                 kmem_free(dp, sizeof (spa_config_dirent_t));
 535         }
 536 
 537         list_destroy(&spa->spa_config_list);
 538 
 539         nvlist_free(spa->spa_label_features);
 540         nvlist_free(spa->spa_load_info);
 541         spa_config_set(spa, NULL);
 542 
 543         refcount_destroy(&spa->spa_refcount);
 544 
 545         spa_config_lock_destroy(spa);
 546 
 547         for (int t = 0; t < TXG_SIZE; t++)
 548                 bplist_destroy(&spa->spa_free_bplist[t]);
 549 
 550         cv_destroy(&spa->spa_async_cv);
 551         cv_destroy(&spa->spa_proc_cv);
 552         cv_destroy(&spa->spa_scrub_io_cv);
 553         cv_destroy(&spa->spa_suspend_cv);
 554 
 555         mutex_destroy(&spa->spa_async_lock);
 556         mutex_destroy(&spa->spa_errlist_lock);
 557         mutex_destroy(&spa->spa_errlog_lock);
 558         mutex_destroy(&spa->spa_history_lock);
 559         mutex_destroy(&spa->spa_proc_lock);
 560         mutex_destroy(&spa->spa_props_lock);
 561         mutex_destroy(&spa->spa_scrub_lock);
 562         mutex_destroy(&spa->spa_suspend_lock);
 563         mutex_destroy(&spa->spa_vdev_top_lock);
 564 
 565         kmem_free(spa, sizeof (spa_t));
 566 }
 567 
 568 /*
 569  * Given a pool, return the next pool in the namespace, or NULL if there is
 570  * none.  If 'prev' is NULL, return the first pool.
 571  */
 572 spa_t *
 573 spa_next(spa_t *prev)
 574 {
 575         ASSERT(MUTEX_HELD(&spa_namespace_lock));
 576 
 577         if (prev)
 578                 return (AVL_NEXT(&spa_namespace_avl, prev));
 579         else
 580                 return (avl_first(&spa_namespace_avl));
 581 }
 582 
 583 /*
 584  * ==========================================================================
 585  * SPA refcount functions
 586  * ==========================================================================
 587  */
 588 
 589 /*
 590  * Add a reference to the given spa_t.  Must have at least one reference, or
 591  * have the namespace lock held.
 592  */
 593 void
 594 spa_open_ref(spa_t *spa, void *tag)
 595 {
 596         ASSERT(refcount_count(&spa->spa_refcount) >= spa->spa_minref ||
 597             MUTEX_HELD(&spa_namespace_lock));
 598         (void) refcount_add(&spa->spa_refcount, tag);
 599 }
 600 
 601 /*
 602  * Remove a reference to the given spa_t.  Must have at least one reference, or
 603  * have the namespace lock held.
 604  */
 605 void
 606 spa_close(spa_t *spa, void *tag)
 607 {
 608         ASSERT(refcount_count(&spa->spa_refcount) > spa->spa_minref ||
 609             MUTEX_HELD(&spa_namespace_lock));
 610         (void) refcount_remove(&spa->spa_refcount, tag);
 611 }
 612 
 613 /*
 614  * Check to see if the spa refcount is zero.  Must be called with
 615  * spa_namespace_lock held.  We really compare against spa_minref, which is the
 616  * number of references acquired when opening a pool
 617  */
 618 boolean_t
 619 spa_refcount_zero(spa_t *spa)
 620 {
 621         ASSERT(MUTEX_HELD(&spa_namespace_lock));
 622 
 623         return (refcount_count(&spa->spa_refcount) == spa->spa_minref);
 624 }
 625 
 626 /*
 627  * ==========================================================================
 628  * SPA spare and l2cache tracking
 629  * ==========================================================================
 630  */
 631 
 632 /*
 633  * Hot spares and cache devices are tracked using the same code below,
 634  * for 'auxiliary' devices.
 635  */
 636 
 637 typedef struct spa_aux {
 638         uint64_t        aux_guid;
 639         uint64_t        aux_pool;
 640         avl_node_t      aux_avl;
 641         int             aux_count;
 642 } spa_aux_t;
 643 
 644 static int
 645 spa_aux_compare(const void *a, const void *b)
 646 {
 647         const spa_aux_t *sa = a;
 648         const spa_aux_t *sb = b;
 649 
 650         if (sa->aux_guid < sb->aux_guid)
 651                 return (-1);
 652         else if (sa->aux_guid > sb->aux_guid)
 653                 return (1);
 654         else
 655                 return (0);
 656 }
 657 
 658 void
 659 spa_aux_add(vdev_t *vd, avl_tree_t *avl)
 660 {
 661         avl_index_t where;
 662         spa_aux_t search;
 663         spa_aux_t *aux;
 664 
 665         search.aux_guid = vd->vdev_guid;
 666         if ((aux = avl_find(avl, &search, &where)) != NULL) {
 667                 aux->aux_count++;
 668         } else {
 669                 aux = kmem_zalloc(sizeof (spa_aux_t), KM_SLEEP);
 670                 aux->aux_guid = vd->vdev_guid;
 671                 aux->aux_count = 1;
 672                 avl_insert(avl, aux, where);
 673         }
 674 }
 675 
 676 void
 677 spa_aux_remove(vdev_t *vd, avl_tree_t *avl)
 678 {
 679         spa_aux_t search;
 680         spa_aux_t *aux;
 681         avl_index_t where;
 682 
 683         search.aux_guid = vd->vdev_guid;
 684         aux = avl_find(avl, &search, &where);
 685 
 686         ASSERT(aux != NULL);
 687 
 688         if (--aux->aux_count == 0) {
 689                 avl_remove(avl, aux);
 690                 kmem_free(aux, sizeof (spa_aux_t));
 691         } else if (aux->aux_pool == spa_guid(vd->vdev_spa)) {
 692                 aux->aux_pool = 0ULL;
 693         }
 694 }
 695 
 696 boolean_t
 697 spa_aux_exists(uint64_t guid, uint64_t *pool, int *refcnt, avl_tree_t *avl)
 698 {
 699         spa_aux_t search, *found;
 700 
 701         search.aux_guid = guid;
 702         found = avl_find(avl, &search, NULL);
 703 
 704         if (pool) {
 705                 if (found)
 706                         *pool = found->aux_pool;
 707                 else
 708                         *pool = 0ULL;
 709         }
 710 
 711         if (refcnt) {
 712                 if (found)
 713                         *refcnt = found->aux_count;
 714                 else
 715                         *refcnt = 0;
 716         }
 717 
 718         return (found != NULL);
 719 }
 720 
 721 void
 722 spa_aux_activate(vdev_t *vd, avl_tree_t *avl)
 723 {
 724         spa_aux_t search, *found;
 725         avl_index_t where;
 726 
 727         search.aux_guid = vd->vdev_guid;
 728         found = avl_find(avl, &search, &where);
 729         ASSERT(found != NULL);
 730         ASSERT(found->aux_pool == 0ULL);
 731 
 732         found->aux_pool = spa_guid(vd->vdev_spa);
 733 }
 734 
 735 /*
 736  * Spares are tracked globally due to the following constraints:
 737  *
 738  *      - A spare may be part of multiple pools.
 739  *      - A spare may be added to a pool even if it's actively in use within
 740  *        another pool.
 741  *      - A spare in use in any pool can only be the source of a replacement if
 742  *        the target is a spare in the same pool.
 743  *
 744  * We keep track of all spares on the system through the use of a reference
 745  * counted AVL tree.  When a vdev is added as a spare, or used as a replacement
 746  * spare, then we bump the reference count in the AVL tree.  In addition, we set
 747  * the 'vdev_isspare' member to indicate that the device is a spare (active or
 748  * inactive).  When a spare is made active (used to replace a device in the
 749  * pool), we also keep track of which pool its been made a part of.
 750  *
 751  * The 'spa_spare_lock' protects the AVL tree.  These functions are normally
 752  * called under the spa_namespace lock as part of vdev reconfiguration.  The
 753  * separate spare lock exists for the status query path, which does not need to
 754  * be completely consistent with respect to other vdev configuration changes.
 755  */
 756 
 757 static int
 758 spa_spare_compare(const void *a, const void *b)
 759 {
 760         return (spa_aux_compare(a, b));
 761 }
 762 
 763 void
 764 spa_spare_add(vdev_t *vd)
 765 {
 766         mutex_enter(&spa_spare_lock);
 767         ASSERT(!vd->vdev_isspare);
 768         spa_aux_add(vd, &spa_spare_avl);
 769         vd->vdev_isspare = B_TRUE;
 770         mutex_exit(&spa_spare_lock);
 771 }
 772 
 773 void
 774 spa_spare_remove(vdev_t *vd)
 775 {
 776         mutex_enter(&spa_spare_lock);
 777         ASSERT(vd->vdev_isspare);
 778         spa_aux_remove(vd, &spa_spare_avl);
 779         vd->vdev_isspare = B_FALSE;
 780         mutex_exit(&spa_spare_lock);
 781 }
 782 
 783 boolean_t
 784 spa_spare_exists(uint64_t guid, uint64_t *pool, int *refcnt)
 785 {
 786         boolean_t found;
 787 
 788         mutex_enter(&spa_spare_lock);
 789         found = spa_aux_exists(guid, pool, refcnt, &spa_spare_avl);
 790         mutex_exit(&spa_spare_lock);
 791 
 792         return (found);
 793 }
 794 
 795 void
 796 spa_spare_activate(vdev_t *vd)
 797 {
 798         mutex_enter(&spa_spare_lock);
 799         ASSERT(vd->vdev_isspare);
 800         spa_aux_activate(vd, &spa_spare_avl);
 801         mutex_exit(&spa_spare_lock);
 802 }
 803 
 804 /*
 805  * Level 2 ARC devices are tracked globally for the same reasons as spares.
 806  * Cache devices currently only support one pool per cache device, and so
 807  * for these devices the aux reference count is currently unused beyond 1.
 808  */
 809 
 810 static int
 811 spa_l2cache_compare(const void *a, const void *b)
 812 {
 813         return (spa_aux_compare(a, b));
 814 }
 815 
 816 void
 817 spa_l2cache_add(vdev_t *vd)
 818 {
 819         mutex_enter(&spa_l2cache_lock);
 820         ASSERT(!vd->vdev_isl2cache);
 821         spa_aux_add(vd, &spa_l2cache_avl);
 822         vd->vdev_isl2cache = B_TRUE;
 823         mutex_exit(&spa_l2cache_lock);
 824 }
 825 
 826 void
 827 spa_l2cache_remove(vdev_t *vd)
 828 {
 829         mutex_enter(&spa_l2cache_lock);
 830         ASSERT(vd->vdev_isl2cache);
 831         spa_aux_remove(vd, &spa_l2cache_avl);
 832         vd->vdev_isl2cache = B_FALSE;
 833         mutex_exit(&spa_l2cache_lock);
 834 }
 835 
 836 boolean_t
 837 spa_l2cache_exists(uint64_t guid, uint64_t *pool)
 838 {
 839         boolean_t found;
 840 
 841         mutex_enter(&spa_l2cache_lock);
 842         found = spa_aux_exists(guid, pool, NULL, &spa_l2cache_avl);
 843         mutex_exit(&spa_l2cache_lock);
 844 
 845         return (found);
 846 }
 847 
 848 void
 849 spa_l2cache_activate(vdev_t *vd)
 850 {
 851         mutex_enter(&spa_l2cache_lock);
 852         ASSERT(vd->vdev_isl2cache);
 853         spa_aux_activate(vd, &spa_l2cache_avl);
 854         mutex_exit(&spa_l2cache_lock);
 855 }
 856 
 857 /*
 858  * ==========================================================================
 859  * SPA vdev locking
 860  * ==========================================================================
 861  */
 862 
 863 /*
 864  * Lock the given spa_t for the purpose of adding or removing a vdev.
 865  * Grabs the global spa_namespace_lock plus the spa config lock for writing.
 866  * It returns the next transaction group for the spa_t.
 867  */
 868 uint64_t
 869 spa_vdev_enter(spa_t *spa)
 870 {
 871         mutex_enter(&spa->spa_vdev_top_lock);
 872         mutex_enter(&spa_namespace_lock);
 873         return (spa_vdev_config_enter(spa));
 874 }
 875 
 876 /*
 877  * Internal implementation for spa_vdev_enter().  Used when a vdev
 878  * operation requires multiple syncs (i.e. removing a device) while
 879  * keeping the spa_namespace_lock held.
 880  */
 881 uint64_t
 882 spa_vdev_config_enter(spa_t *spa)
 883 {
 884         ASSERT(MUTEX_HELD(&spa_namespace_lock));
 885 
 886         spa_config_enter(spa, SCL_ALL, spa, RW_WRITER);
 887 
 888         return (spa_last_synced_txg(spa) + 1);
 889 }
 890 
 891 /*
 892  * Used in combination with spa_vdev_config_enter() to allow the syncing
 893  * of multiple transactions without releasing the spa_namespace_lock.
 894  */
 895 void
 896 spa_vdev_config_exit(spa_t *spa, vdev_t *vd, uint64_t txg, int error, char *tag)
 897 {
 898         ASSERT(MUTEX_HELD(&spa_namespace_lock));
 899 
 900         int config_changed = B_FALSE;
 901 
 902         ASSERT(txg > spa_last_synced_txg(spa));
 903 
 904         spa->spa_pending_vdev = NULL;
 905 
 906         /*
 907          * Reassess the DTLs.
 908          */
 909         vdev_dtl_reassess(spa->spa_root_vdev, 0, 0, B_FALSE);
 910 
 911         if (error == 0 && !list_is_empty(&spa->spa_config_dirty_list)) {
 912                 config_changed = B_TRUE;
 913                 spa->spa_config_generation++;
 914         }
 915 
 916         /*
 917          * Verify the metaslab classes.
 918          */
 919         ASSERT(metaslab_class_validate(spa_normal_class(spa)) == 0);
 920         ASSERT(metaslab_class_validate(spa_log_class(spa)) == 0);
 921 
 922         spa_config_exit(spa, SCL_ALL, spa);
 923 
 924         /*
 925          * Panic the system if the specified tag requires it.  This
 926          * is useful for ensuring that configurations are updated
 927          * transactionally.
 928          */
 929         if (zio_injection_enabled)
 930                 zio_handle_panic_injection(spa, tag, 0);
 931 
 932         /*
 933          * Note: this txg_wait_synced() is important because it ensures
 934          * that there won't be more than one config change per txg.
 935          * This allows us to use the txg as the generation number.
 936          */
 937         if (error == 0)
 938                 txg_wait_synced(spa->spa_dsl_pool, txg);
 939 
 940         if (vd != NULL) {
 941                 ASSERT(!vd->vdev_detached || vd->vdev_dtl_smo.smo_object == 0);
 942                 spa_config_enter(spa, SCL_ALL, spa, RW_WRITER);
 943                 vdev_free(vd);
 944                 spa_config_exit(spa, SCL_ALL, spa);
 945         }
 946 
 947         /*
 948          * If the config changed, update the config cache.
 949          */
 950         if (config_changed)
 951                 spa_config_sync(spa, B_FALSE, B_TRUE);
 952 }
 953 
 954 /*
 955  * Unlock the spa_t after adding or removing a vdev.  Besides undoing the
 956  * locking of spa_vdev_enter(), we also want make sure the transactions have
 957  * synced to disk, and then update the global configuration cache with the new
 958  * information.
 959  */
 960 int
 961 spa_vdev_exit(spa_t *spa, vdev_t *vd, uint64_t txg, int error)
 962 {
 963         spa_vdev_config_exit(spa, vd, txg, error, FTAG);
 964         mutex_exit(&spa_namespace_lock);
 965         mutex_exit(&spa->spa_vdev_top_lock);
 966 
 967         return (error);
 968 }
 969 
 970 /*
 971  * Lock the given spa_t for the purpose of changing vdev state.
 972  */
 973 void
 974 spa_vdev_state_enter(spa_t *spa, int oplocks)
 975 {
 976         int locks = SCL_STATE_ALL | oplocks;
 977 
 978         /*
 979          * Root pools may need to read of the underlying devfs filesystem
 980          * when opening up a vdev.  Unfortunately if we're holding the
 981          * SCL_ZIO lock it will result in a deadlock when we try to issue
 982          * the read from the root filesystem.  Instead we "prefetch"
 983          * the associated vnodes that we need prior to opening the
 984          * underlying devices and cache them so that we can prevent
 985          * any I/O when we are doing the actual open.
 986          */
 987         if (spa_is_root(spa)) {
 988                 int low = locks & ~(SCL_ZIO - 1);
 989                 int high = locks & ~low;
 990 
 991                 spa_config_enter(spa, high, spa, RW_WRITER);
 992                 vdev_hold(spa->spa_root_vdev);
 993                 spa_config_enter(spa, low, spa, RW_WRITER);
 994         } else {
 995                 spa_config_enter(spa, locks, spa, RW_WRITER);
 996         }
 997         spa->spa_vdev_locks = locks;
 998 }
 999 
1000 int
1001 spa_vdev_state_exit(spa_t *spa, vdev_t *vd, int error)
1002 {
1003         boolean_t config_changed = B_FALSE;
1004 
1005         if (vd != NULL || error == 0)
1006                 vdev_dtl_reassess(vd ? vd->vdev_top : spa->spa_root_vdev,
1007                     0, 0, B_FALSE);
1008 
1009         if (vd != NULL) {
1010                 vdev_state_dirty(vd->vdev_top);
1011                 config_changed = B_TRUE;
1012                 spa->spa_config_generation++;
1013         }
1014 
1015         if (spa_is_root(spa))
1016                 vdev_rele(spa->spa_root_vdev);
1017 
1018         ASSERT3U(spa->spa_vdev_locks, >=, SCL_STATE_ALL);
1019         spa_config_exit(spa, spa->spa_vdev_locks, spa);
1020 
1021         /*
1022          * If anything changed, wait for it to sync.  This ensures that,
1023          * from the system administrator's perspective, zpool(1M) commands
1024          * are synchronous.  This is important for things like zpool offline:
1025          * when the command completes, you expect no further I/O from ZFS.
1026          */
1027         if (vd != NULL)
1028                 txg_wait_synced(spa->spa_dsl_pool, 0);
1029 
1030         /*
1031          * If the config changed, update the config cache.
1032          */
1033         if (config_changed) {
1034                 mutex_enter(&spa_namespace_lock);
1035                 spa_config_sync(spa, B_FALSE, B_TRUE);
1036                 mutex_exit(&spa_namespace_lock);
1037         }
1038 
1039         return (error);
1040 }
1041 
1042 /*
1043  * ==========================================================================
1044  * Miscellaneous functions
1045  * ==========================================================================
1046  */
1047 
1048 void
1049 spa_activate_mos_feature(spa_t *spa, const char *feature)
1050 {
1051         (void) nvlist_add_boolean(spa->spa_label_features, feature);
1052         vdev_config_dirty(spa->spa_root_vdev);
1053 }
1054 
1055 void
1056 spa_deactivate_mos_feature(spa_t *spa, const char *feature)
1057 {
1058         (void) nvlist_remove_all(spa->spa_label_features, feature);
1059         vdev_config_dirty(spa->spa_root_vdev);
1060 }
1061 
1062 /*
1063  * Rename a spa_t.
1064  */
1065 int
1066 spa_rename(const char *name, const char *newname)
1067 {
1068         spa_t *spa;
1069         int err;
1070 
1071         /*
1072          * Lookup the spa_t and grab the config lock for writing.  We need to
1073          * actually open the pool so that we can sync out the necessary labels.
1074          * It's OK to call spa_open() with the namespace lock held because we
1075          * allow recursive calls for other reasons.
1076          */
1077         mutex_enter(&spa_namespace_lock);
1078         if ((err = spa_open(name, &spa, FTAG)) != 0) {
1079                 mutex_exit(&spa_namespace_lock);
1080                 return (err);
1081         }
1082 
1083         spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
1084 
1085         avl_remove(&spa_namespace_avl, spa);
1086         (void) strlcpy(spa->spa_name, newname, sizeof (spa->spa_name));
1087         avl_add(&spa_namespace_avl, spa);
1088 
1089         /*
1090          * Sync all labels to disk with the new names by marking the root vdev
1091          * dirty and waiting for it to sync.  It will pick up the new pool name
1092          * during the sync.
1093          */
1094         vdev_config_dirty(spa->spa_root_vdev);
1095 
1096         spa_config_exit(spa, SCL_ALL, FTAG);
1097 
1098         txg_wait_synced(spa->spa_dsl_pool, 0);
1099 
1100         /*
1101          * Sync the updated config cache.
1102          */
1103         spa_config_sync(spa, B_FALSE, B_TRUE);
1104 
1105         spa_close(spa, FTAG);
1106 
1107         mutex_exit(&spa_namespace_lock);
1108 
1109         return (0);
1110 }
1111 
1112 /*
1113  * Return the spa_t associated with given pool_guid, if it exists.  If
1114  * device_guid is non-zero, determine whether the pool exists *and* contains
1115  * a device with the specified device_guid.
1116  */
1117 spa_t *
1118 spa_by_guid(uint64_t pool_guid, uint64_t device_guid)
1119 {
1120         spa_t *spa;
1121         avl_tree_t *t = &spa_namespace_avl;
1122 
1123         ASSERT(MUTEX_HELD(&spa_namespace_lock));
1124 
1125         for (spa = avl_first(t); spa != NULL; spa = AVL_NEXT(t, spa)) {
1126                 if (spa->spa_state == POOL_STATE_UNINITIALIZED)
1127                         continue;
1128                 if (spa->spa_root_vdev == NULL)
1129                         continue;
1130                 if (spa_guid(spa) == pool_guid) {
1131                         if (device_guid == 0)
1132                                 break;
1133 
1134                         if (vdev_lookup_by_guid(spa->spa_root_vdev,
1135                             device_guid) != NULL)
1136                                 break;
1137 
1138                         /*
1139                          * Check any devices we may be in the process of adding.
1140                          */
1141                         if (spa->spa_pending_vdev) {
1142                                 if (vdev_lookup_by_guid(spa->spa_pending_vdev,
1143                                     device_guid) != NULL)
1144                                         break;
1145                         }
1146                 }
1147         }
1148 
1149         return (spa);
1150 }
1151 
1152 /*
1153  * Determine whether a pool with the given pool_guid exists.
1154  */
1155 boolean_t
1156 spa_guid_exists(uint64_t pool_guid, uint64_t device_guid)
1157 {
1158         return (spa_by_guid(pool_guid, device_guid) != NULL);
1159 }
1160 
1161 char *
1162 spa_strdup(const char *s)
1163 {
1164         size_t len;
1165         char *new;
1166 
1167         len = strlen(s);
1168         new = kmem_alloc(len + 1, KM_SLEEP);
1169         bcopy(s, new, len);
1170         new[len] = '\0';
1171 
1172         return (new);
1173 }
1174 
1175 void
1176 spa_strfree(char *s)
1177 {
1178         kmem_free(s, strlen(s) + 1);
1179 }
1180 
1181 uint64_t
1182 spa_get_random(uint64_t range)
1183 {
1184         uint64_t r;
1185 
1186         ASSERT(range != 0);
1187 
1188         (void) random_get_pseudo_bytes((void *)&r, sizeof (uint64_t));
1189 
1190         return (r % range);
1191 }
1192 
1193 uint64_t
1194 spa_generate_guid(spa_t *spa)
1195 {
1196         uint64_t guid = spa_get_random(-1ULL);
1197 
1198         if (spa != NULL) {
1199                 while (guid == 0 || spa_guid_exists(spa_guid(spa), guid))
1200                         guid = spa_get_random(-1ULL);
1201         } else {
1202                 while (guid == 0 || spa_guid_exists(guid, 0))
1203                         guid = spa_get_random(-1ULL);
1204         }
1205 
1206         return (guid);
1207 }
1208 
1209 void
1210 sprintf_blkptr(char *buf, const blkptr_t *bp)
1211 {
1212         char type[256];
1213         char *checksum = NULL;
1214         char *compress = NULL;
1215 
1216         if (bp != NULL) {
1217                 if (BP_GET_TYPE(bp) & DMU_OT_NEWTYPE) {
1218                         dmu_object_byteswap_t bswap =
1219                             DMU_OT_BYTESWAP(BP_GET_TYPE(bp));
1220                         (void) snprintf(type, sizeof (type), "bswap %s %s",
1221                             DMU_OT_IS_METADATA(BP_GET_TYPE(bp)) ?
1222                             "metadata" : "data",
1223                             dmu_ot_byteswap[bswap].ob_name);
1224                 } else {
1225                         (void) strlcpy(type, dmu_ot[BP_GET_TYPE(bp)].ot_name,
1226                             sizeof (type));
1227                 }
1228                 checksum = zio_checksum_table[BP_GET_CHECKSUM(bp)].ci_name;
1229                 compress = zio_compress_table[BP_GET_COMPRESS(bp)].ci_name;
1230         }
1231 
1232         SPRINTF_BLKPTR(snprintf, ' ', buf, bp, type, checksum, compress);
1233 }
1234 
1235 void
1236 spa_freeze(spa_t *spa)
1237 {
1238         uint64_t freeze_txg = 0;
1239 
1240         spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
1241         if (spa->spa_freeze_txg == UINT64_MAX) {
1242                 freeze_txg = spa_last_synced_txg(spa) + TXG_SIZE;
1243                 spa->spa_freeze_txg = freeze_txg;
1244         }
1245         spa_config_exit(spa, SCL_ALL, FTAG);
1246         if (freeze_txg != 0)
1247                 txg_wait_synced(spa_get_dsl(spa), freeze_txg);
1248 }
1249 
1250 void
1251 zfs_panic_recover(const char *fmt, ...)
1252 {
1253         va_list adx;
1254 
1255         va_start(adx, fmt);
1256         vcmn_err(zfs_recover ? CE_WARN : CE_PANIC, fmt, adx);
1257         va_end(adx);
1258 }
1259 
1260 /*
1261  * This is a stripped-down version of strtoull, suitable only for converting
1262  * lowercase hexidecimal numbers that don't overflow.
1263  */
1264 uint64_t
1265 strtonum(const char *str, char **nptr)
1266 {
1267         uint64_t val = 0;
1268         char c;
1269         int digit;
1270 
1271         while ((c = *str) != '\0') {
1272                 if (c >= '0' && c <= '9')
1273                         digit = c - '0';
1274                 else if (c >= 'a' && c <= 'f')
1275                         digit = 10 + c - 'a';
1276                 else
1277                         break;
1278 
1279                 val *= 16;
1280                 val += digit;
1281 
1282                 str++;
1283         }
1284 
1285         if (nptr)
1286                 *nptr = (char *)str;
1287 
1288         return (val);
1289 }
1290 
1291 /*
1292  * ==========================================================================
1293  * Accessor functions
1294  * ==========================================================================
1295  */
1296 
1297 boolean_t
1298 spa_shutting_down(spa_t *spa)
1299 {
1300         return (spa->spa_async_suspended);
1301 }
1302 
1303 dsl_pool_t *
1304 spa_get_dsl(spa_t *spa)
1305 {
1306         return (spa->spa_dsl_pool);
1307 }
1308 
1309 boolean_t
1310 spa_is_initializing(spa_t *spa)
1311 {
1312         return (spa->spa_is_initializing);
1313 }
1314 
1315 blkptr_t *
1316 spa_get_rootblkptr(spa_t *spa)
1317 {
1318         return (&spa->spa_ubsync.ub_rootbp);
1319 }
1320 
1321 void
1322 spa_set_rootblkptr(spa_t *spa, const blkptr_t *bp)
1323 {
1324         spa->spa_uberblock.ub_rootbp = *bp;
1325 }
1326 
1327 void
1328 spa_altroot(spa_t *spa, char *buf, size_t buflen)
1329 {
1330         if (spa->spa_root == NULL)
1331                 buf[0] = '\0';
1332         else
1333                 (void) strncpy(buf, spa->spa_root, buflen);
1334 }
1335 
1336 int
1337 spa_sync_pass(spa_t *spa)
1338 {
1339         return (spa->spa_sync_pass);
1340 }
1341 
1342 char *
1343 spa_name(spa_t *spa)
1344 {
1345         return (spa->spa_name);
1346 }
1347 
1348 uint64_t
1349 spa_guid(spa_t *spa)
1350 {
1351         /*
1352          * If we fail to parse the config during spa_load(), we can go through
1353          * the error path (which posts an ereport) and end up here with no root
1354          * vdev.  We stash the original pool guid in 'spa_config_guid' to handle
1355          * this case.
1356          */
1357         if (spa->spa_root_vdev != NULL)
1358                 return (spa->spa_root_vdev->vdev_guid);
1359         else
1360                 return (spa->spa_config_guid);
1361 }
1362 
1363 uint64_t
1364 spa_load_guid(spa_t *spa)
1365 {
1366         /*
1367          * This is a GUID that exists solely as a reference for the
1368          * purposes of the arc.  It is generated at load time, and
1369          * is never written to persistent storage.
1370          */
1371         return (spa->spa_load_guid);
1372 }
1373 
1374 uint64_t
1375 spa_last_synced_txg(spa_t *spa)
1376 {
1377         return (spa->spa_ubsync.ub_txg);
1378 }
1379 
1380 uint64_t
1381 spa_first_txg(spa_t *spa)
1382 {
1383         return (spa->spa_first_txg);
1384 }
1385 
1386 uint64_t
1387 spa_syncing_txg(spa_t *spa)
1388 {
1389         return (spa->spa_syncing_txg);
1390 }
1391 
1392 pool_state_t
1393 spa_state(spa_t *spa)
1394 {
1395         return (spa->spa_state);
1396 }
1397 
1398 spa_load_state_t
1399 spa_load_state(spa_t *spa)
1400 {
1401         return (spa->spa_load_state);
1402 }
1403 
1404 uint64_t
1405 spa_freeze_txg(spa_t *spa)
1406 {
1407         return (spa->spa_freeze_txg);
1408 }
1409 
1410 /* ARGSUSED */
1411 uint64_t
1412 spa_get_asize(spa_t *spa, uint64_t lsize)
1413 {
1414         /*
1415          * The worst case is single-sector max-parity RAID-Z blocks, in which
1416          * case the space requirement is exactly (VDEV_RAIDZ_MAXPARITY + 1)
1417          * times the size; so just assume that.  Add to this the fact that
1418          * we can have up to 3 DVAs per bp, and one more factor of 2 because
1419          * the block may be dittoed with up to 3 DVAs by ddt_sync().
1420          */
1421         return (lsize * (VDEV_RAIDZ_MAXPARITY + 1) * SPA_DVAS_PER_BP * 2);
1422 }
1423 
1424 uint64_t
1425 spa_get_dspace(spa_t *spa)
1426 {
1427         return (spa->spa_dspace);
1428 }
1429 
1430 void
1431 spa_update_dspace(spa_t *spa)
1432 {
1433         spa->spa_dspace = metaslab_class_get_dspace(spa_normal_class(spa)) +
1434             ddt_get_dedup_dspace(spa);
1435 }
1436 
1437 /*
1438  * Return the failure mode that has been set to this pool. The default
1439  * behavior will be to block all I/Os when a complete failure occurs.
1440  */
1441 uint8_t
1442 spa_get_failmode(spa_t *spa)
1443 {
1444         return (spa->spa_failmode);
1445 }
1446 
1447 boolean_t
1448 spa_suspended(spa_t *spa)
1449 {
1450         return (spa->spa_suspended);
1451 }
1452 
1453 uint64_t
1454 spa_version(spa_t *spa)
1455 {
1456         return (spa->spa_ubsync.ub_version);
1457 }
1458 
1459 boolean_t
1460 spa_deflate(spa_t *spa)
1461 {
1462         return (spa->spa_deflate);
1463 }
1464 
1465 metaslab_class_t *
1466 spa_normal_class(spa_t *spa)
1467 {
1468         return (spa->spa_normal_class);
1469 }
1470 
1471 metaslab_class_t *
1472 spa_log_class(spa_t *spa)
1473 {
1474         return (spa->spa_log_class);
1475 }
1476 
1477 int
1478 spa_max_replication(spa_t *spa)
1479 {
1480         /*
1481          * As of SPA_VERSION == SPA_VERSION_DITTO_BLOCKS, we are able to
1482          * handle BPs with more than one DVA allocated.  Set our max
1483          * replication level accordingly.
1484          */
1485         if (spa_version(spa) < SPA_VERSION_DITTO_BLOCKS)
1486                 return (1);
1487         return (MIN(SPA_DVAS_PER_BP, spa_max_replication_override));
1488 }
1489 
1490 int
1491 spa_prev_software_version(spa_t *spa)
1492 {
1493         return (spa->spa_prev_software_version);
1494 }
1495 
1496 uint64_t
1497 dva_get_dsize_sync(spa_t *spa, const dva_t *dva)
1498 {
1499         uint64_t asize = DVA_GET_ASIZE(dva);
1500         uint64_t dsize = asize;
1501 
1502         ASSERT(spa_config_held(spa, SCL_ALL, RW_READER) != 0);
1503 
1504         if (asize != 0 && spa->spa_deflate) {
1505                 vdev_t *vd = vdev_lookup_top(spa, DVA_GET_VDEV(dva));
1506                 dsize = (asize >> SPA_MINBLOCKSHIFT) * vd->vdev_deflate_ratio;
1507         }
1508 
1509         return (dsize);
1510 }
1511 
1512 uint64_t
1513 bp_get_dsize_sync(spa_t *spa, const blkptr_t *bp)
1514 {
1515         uint64_t dsize = 0;
1516 
1517         for (int d = 0; d < SPA_DVAS_PER_BP; d++)
1518                 dsize += dva_get_dsize_sync(spa, &bp->blk_dva[d]);
1519 
1520         return (dsize);
1521 }
1522 
1523 uint64_t
1524 bp_get_dsize(spa_t *spa, const blkptr_t *bp)
1525 {
1526         uint64_t dsize = 0;
1527 
1528         spa_config_enter(spa, SCL_VDEV, FTAG, RW_READER);
1529 
1530         for (int d = 0; d < SPA_DVAS_PER_BP; d++)
1531                 dsize += dva_get_dsize_sync(spa, &bp->blk_dva[d]);
1532 
1533         spa_config_exit(spa, SCL_VDEV, FTAG);
1534 
1535         return (dsize);
1536 }
1537 
1538 /*
1539  * ==========================================================================
1540  * Initialization and Termination
1541  * ==========================================================================
1542  */
1543 
1544 static int
1545 spa_name_compare(const void *a1, const void *a2)
1546 {
1547         const spa_t *s1 = a1;
1548         const spa_t *s2 = a2;
1549         int s;
1550 
1551         s = strcmp(s1->spa_name, s2->spa_name);
1552         if (s > 0)
1553                 return (1);
1554         if (s < 0)
1555                 return (-1);
1556         return (0);
1557 }
1558 
1559 int
1560 spa_busy(void)
1561 {
1562         return (spa_active_count);
1563 }
1564 
1565 void
1566 spa_boot_init()
1567 {
1568         spa_config_load();
1569 }
1570 
1571 void
1572 spa_init(int mode)
1573 {
1574         mutex_init(&spa_namespace_lock, NULL, MUTEX_DEFAULT, NULL);
1575         mutex_init(&spa_spare_lock, NULL, MUTEX_DEFAULT, NULL);
1576         mutex_init(&spa_l2cache_lock, NULL, MUTEX_DEFAULT, NULL);
1577         cv_init(&spa_namespace_cv, NULL, CV_DEFAULT, NULL);
1578 
1579         avl_create(&spa_namespace_avl, spa_name_compare, sizeof (spa_t),
1580             offsetof(spa_t, spa_avl));
1581 
1582         avl_create(&spa_spare_avl, spa_spare_compare, sizeof (spa_aux_t),
1583             offsetof(spa_aux_t, aux_avl));
1584 
1585         avl_create(&spa_l2cache_avl, spa_l2cache_compare, sizeof (spa_aux_t),
1586             offsetof(spa_aux_t, aux_avl));
1587 
1588         spa_mode_global = mode;
1589 
1590         refcount_init();
1591         unique_init();
1592         zio_init();
1593         dmu_init();
1594         zil_init();
1595         vdev_cache_stat_init();
1596         zfs_prop_init();
1597         zpool_prop_init();
1598         zpool_feature_init();
1599         spa_config_load();
1600         l2arc_start();
1601 }
1602 
1603 void
1604 spa_fini(void)
1605 {
1606         l2arc_stop();
1607 
1608         spa_evict_all();
1609 
1610         vdev_cache_stat_fini();
1611         zil_fini();
1612         dmu_fini();
1613         zio_fini();
1614         unique_fini();
1615         refcount_fini();
1616 
1617         avl_destroy(&spa_namespace_avl);
1618         avl_destroy(&spa_spare_avl);
1619         avl_destroy(&spa_l2cache_avl);
1620 
1621         cv_destroy(&spa_namespace_cv);
1622         mutex_destroy(&spa_namespace_lock);
1623         mutex_destroy(&spa_spare_lock);
1624         mutex_destroy(&spa_l2cache_lock);
1625 }
1626 
1627 /*
1628  * Return whether this pool has slogs. No locking needed.
1629  * It's not a problem if the wrong answer is returned as it's only for
1630  * performance and not correctness
1631  */
1632 boolean_t
1633 spa_has_slogs(spa_t *spa)
1634 {
1635         return (spa->spa_log_class->mc_rotor != NULL);
1636 }
1637 
1638 spa_log_state_t
1639 spa_get_log_state(spa_t *spa)
1640 {
1641         return (spa->spa_log_state);
1642 }
1643 
1644 void
1645 spa_set_log_state(spa_t *spa, spa_log_state_t state)
1646 {
1647         spa->spa_log_state = state;
1648 }
1649 
1650 boolean_t
1651 spa_is_root(spa_t *spa)
1652 {
1653         return (spa->spa_is_root);
1654 }
1655 
1656 boolean_t
1657 spa_writeable(spa_t *spa)
1658 {
1659         return (!!(spa->spa_mode & FWRITE));
1660 }
1661 
1662 int
1663 spa_mode(spa_t *spa)
1664 {
1665         return (spa->spa_mode);
1666 }
1667 
1668 uint64_t
1669 spa_bootfs(spa_t *spa)
1670 {
1671         return (spa->spa_bootfs);
1672 }
1673 
1674 uint64_t
1675 spa_delegation(spa_t *spa)
1676 {
1677         return (spa->spa_delegation);
1678 }
1679 
1680 objset_t *
1681 spa_meta_objset(spa_t *spa)
1682 {
1683         return (spa->spa_meta_objset);
1684 }
1685 
1686 enum zio_checksum
1687 spa_dedup_checksum(spa_t *spa)
1688 {
1689         return (spa->spa_dedup_checksum);
1690 }
1691 
1692 /*
1693  * Reset pool scan stat per scan pass (or reboot).
1694  */
1695 void
1696 spa_scan_stat_init(spa_t *spa)
1697 {
1698         /* data not stored on disk */
1699         spa->spa_scan_pass_start = gethrestime_sec();
1700         spa->spa_scan_pass_exam = 0;
1701         vdev_scan_stat_init(spa->spa_root_vdev);
1702 }
1703 
1704 /*
1705  * Get scan stats for zpool status reports
1706  */
1707 int
1708 spa_scan_get_stats(spa_t *spa, pool_scan_stat_t *ps)
1709 {
1710         dsl_scan_t *scn = spa->spa_dsl_pool ? spa->spa_dsl_pool->dp_scan : NULL;
1711 
1712         if (scn == NULL || scn->scn_phys.scn_func == POOL_SCAN_NONE)
1713                 return (ENOENT);
1714         bzero(ps, sizeof (pool_scan_stat_t));
1715 
1716         /* data stored on disk */
1717         ps->pss_func = scn->scn_phys.scn_func;
1718         ps->pss_start_time = scn->scn_phys.scn_start_time;
1719         ps->pss_end_time = scn->scn_phys.scn_end_time;
1720         ps->pss_to_examine = scn->scn_phys.scn_to_examine;
1721         ps->pss_examined = scn->scn_phys.scn_examined;
1722         ps->pss_to_process = scn->scn_phys.scn_to_process;
1723         ps->pss_processed = scn->scn_phys.scn_processed;
1724         ps->pss_errors = scn->scn_phys.scn_errors;
1725         ps->pss_state = scn->scn_phys.scn_state;
1726 
1727         /* data not stored on disk */
1728         ps->pss_pass_start = spa->spa_scan_pass_start;
1729         ps->pss_pass_exam = spa->spa_scan_pass_exam;
1730 
1731         return (0);
1732 }
1733 
1734 boolean_t
1735 spa_debug_enabled(spa_t *spa)
1736 {
1737         return (spa->spa_debug);
1738 }