zpool import speedup

   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) 2013 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/spa_boot.h>
  30 #include <sys/zio.h>
  31 #include <sys/zio_checksum.h>
  32 #include <sys/zio_compress.h>
  33 #include <sys/dmu.h>
  34 #include <sys/dmu_tx.h>
  35 #include <sys/zap.h>
  36 #include <sys/zil.h>
  37 #include <sys/vdev_impl.h>
  38 #include <sys/metaslab.h>
  39 #include <sys/uberblock_impl.h>
  40 #include <sys/txg.h>
  41 #include <sys/avl.h>
  42 #include <sys/unique.h>
  43 #include <sys/dsl_pool.h>
  44 #include <sys/dsl_dir.h>
  45 #include <sys/dsl_prop.h>
  46 #include <sys/dsl_scan.h>
  47 #include <sys/fs/zfs.h>
  48 #include <sys/metaslab_impl.h>
  49 #include <sys/arc.h>
  50 #include <sys/ddt.h>
  51 #include "zfs_prop.h"
  52 #include "zfeature_common.h"
  53 
  54 /*
  55  * SPA locking
  56  *
  57  * There are four basic locks for managing spa_t structures:
  58  *
  59  * spa_namespace_lock (global mutex)
  60  *
  61  *      This lock must be acquired to do any of the following:
  62  *
  63  *              - Lookup a spa_t by name
  64  *              - Add or remove a spa_t from the namespace
  65  *              - Increase spa_refcount from non-zero
  66  *              - Check if spa_refcount is zero
  67  *              - Rename a spa_t
  68  *              - add/remove/attach/detach devices
  69  *              - Held for the duration of create/destroy/import/export
  70  *
  71  *      It does not need to handle recursion.  A create or destroy may
  72  *      reference objects (files or zvols) in other pools, but by
  73  *      definition they must have an existing reference, and will never need
  74  *      to lookup a spa_t by name.
  75  *
  76  * spa_refcount (per-spa refcount_t protected by mutex)
  77  *
  78  *      This reference count keep track of any active users of the spa_t.  The
  79  *      spa_t cannot be destroyed or freed while this is non-zero.  Internally,
  80  *      the refcount is never really 'zero' - opening a pool implicitly keeps
  81  *      some references in the DMU.  Internally we check against spa_minref, but
  82  *      present the image of a zero/non-zero value to consumers.
  83  *
  84  * spa_config_lock[] (per-spa array of rwlocks)
  85  *
  86  *      This protects the spa_t from config changes, and must be held in
  87  *      the following circumstances:
  88  *
  89  *              - RW_READER to perform I/O to the spa
  90  *              - RW_WRITER to change the vdev config
  91  *
  92  * The locking order is fairly straightforward:
  93  *
  94  *              spa_namespace_lock      ->   spa_refcount
  95  *
  96  *      The namespace lock must be acquired to increase the refcount from 0
  97  *      or to check if it is zero.
  98  *
  99  *              spa_refcount            ->   spa_config_lock[]
 100  *
 101  *      There must be at least one valid reference on the spa_t to acquire
 102  *      the config lock.
 103  *
 104  *              spa_namespace_lock      ->   spa_config_lock[]
 105  *
 106  *      The namespace lock must always be taken before the config lock.
 107  *
 108  *
 109  * The spa_namespace_lock can be acquired directly and is globally visible.
 110  *
 111  * The namespace is manipulated using the following functions, all of which
 112  * require the spa_namespace_lock to be held.
 113  *
 114  *      spa_lookup()            Lookup a spa_t by name.
 115  *
 116  *      spa_add()               Create a new spa_t in the namespace.
 117  *
 118  *      spa_remove()            Remove a spa_t from the namespace.  This also
 119  *                              frees up any memory associated with the spa_t.
 120  *
 121  *      spa_next()              Returns the next spa_t in the system, or the
 122  *                              first if NULL is passed.
 123  *
 124  *      spa_evict_all()         Shutdown and remove all spa_t structures in
 125  *                              the system.
 126  *
 127  *      spa_guid_exists()       Determine whether a pool/device guid exists.
 128  *
 129  * The spa_refcount is manipulated using the following functions:
 130  *
 131  *      spa_open_ref()          Adds a reference to the given spa_t.  Must be
 132  *                              called with spa_namespace_lock held if the
 133  *                              refcount is currently zero.
 134  *
 135  *      spa_close()             Remove a reference from the spa_t.  This will
 136  *                              not free the spa_t or remove it from the
 137  *                              namespace.  No locking is required.
 138  *
 139  *      spa_refcount_zero()     Returns true if the refcount is currently
 140  *                              zero.  Must be called with spa_namespace_lock
 141  *                              held.
 142  *
 143  * The spa_config_lock[] is an array of rwlocks, ordered as follows:
 144  * SCL_CONFIG > SCL_STATE > SCL_ALLOC > SCL_ZIO > SCL_FREE > SCL_VDEV.
 145  * spa_config_lock[] is manipulated with spa_config_{enter,exit,held}().
 146  *
 147  * To read the configuration, it suffices to hold one of these locks as reader.
 148  * To modify the configuration, you must hold all locks as writer.  To modify
 149  * vdev state without altering the vdev tree's topology (e.g. online/offline),
 150  * you must hold SCL_STATE and SCL_ZIO as writer.
 151  *
 152  * We use these distinct config locks to avoid recursive lock entry.
 153  * For example, spa_sync() (which holds SCL_CONFIG as reader) induces
 154  * block allocations (SCL_ALLOC), which may require reading space maps
 155  * from disk (dmu_read() -> zio_read() -> SCL_ZIO).
 156  *
 157  * The spa config locks cannot be normal rwlocks because we need the
 158  * ability to hand off ownership.  For example, SCL_ZIO is acquired
 159  * by the issuing thread and later released by an interrupt thread.
 160  * They do, however, obey the usual write-wanted semantics to prevent
 161  * writer (i.e. system administrator) starvation.
 162  *
 163  * The lock acquisition rules are as follows:
 164  *
 165  * SCL_CONFIG
 166  *      Protects changes to the vdev tree topology, such as vdev
 167  *      add/remove/attach/detach.  Protects the dirty config list
 168  *      (spa_config_dirty_list) and the set of spares and l2arc devices.
 169  *
 170  * SCL_STATE
 171  *      Protects changes to pool state and vdev state, such as vdev
 172  *      online/offline/fault/degrade/clear.  Protects the dirty state list
 173  *      (spa_state_dirty_list) and global pool state (spa_state).
 174  *
 175  * SCL_ALLOC
 176  *      Protects changes to metaslab groups and classes.
 177  *      Held as reader by metaslab_alloc() and metaslab_claim().
 178  *
 179  * SCL_ZIO
 180  *      Held by bp-level zios (those which have no io_vd upon entry)
 181  *      to prevent changes to the vdev tree.  The bp-level zio implicitly
 182  *      protects all of its vdev child zios, which do not hold SCL_ZIO.
 183  *
 184  * SCL_FREE
 185  *      Protects changes to metaslab groups and classes.
 186  *      Held as reader by metaslab_free().  SCL_FREE is distinct from
 187  *      SCL_ALLOC, and lower than SCL_ZIO, so that we can safely free
 188  *      blocks in zio_done() while another i/o that holds either
 189  *      SCL_ALLOC or SCL_ZIO is waiting for this i/o to complete.
 190  *
 191  * SCL_VDEV
 192  *      Held as reader to prevent changes to the vdev tree during trivial
 193  *      inquiries such as bp_get_dsize().  SCL_VDEV is distinct from the
 194  *      other locks, and lower than all of them, to ensure that it's safe
 195  *      to acquire regardless of caller context.
 196  *
 197  * In addition, the following rules apply:
 198  *
 199  * (a)  spa_props_lock protects pool properties, spa_config and spa_config_list.
 200  *      The lock ordering is SCL_CONFIG > spa_props_lock.
 201  *
 202  * (b)  I/O operations on leaf vdevs.  For any zio operation that takes
 203  *      an explicit vdev_t argument -- such as zio_ioctl(), zio_read_phys(),
 204  *      or zio_write_phys() -- the caller must ensure that the config cannot
 205  *      cannot change in the interim, and that the vdev cannot be reopened.
 206  *      SCL_STATE as reader suffices for both.
 207  *
 208  * The vdev configuration is protected by spa_vdev_enter() / spa_vdev_exit().
 209  *
 210  *      spa_vdev_enter()        Acquire the namespace lock and the config lock
 211  *                              for writing.
 212  *
 213  *      spa_vdev_exit()         Release the config lock, wait for all I/O
 214  *                              to complete, sync the updated configs to the
 215  *                              cache, and release the namespace lock.
 216  *
 217  * vdev state is protected by spa_vdev_state_enter() / spa_vdev_state_exit().
 218  * Like spa_vdev_enter/exit, these are convenience wrappers -- the actual
 219  * locking is, always, based on spa_namespace_lock and spa_config_lock[].
 220  *
 221  * spa_rename() is also implemented within this file since it requires
 222  * manipulation of the namespace.
 223  */
 224 
 225 static avl_tree_t spa_namespace_avl;
 226 kmutex_t spa_namespace_lock;
 227 static kcondvar_t spa_namespace_cv;
 228 static int spa_active_count;
 229 int spa_max_replication_override = SPA_DVAS_PER_BP;
 230 
 231 static kmutex_t spa_spare_lock;
 232 static avl_tree_t spa_spare_avl;
 233 static kmutex_t spa_l2cache_lock;
 234 static avl_tree_t spa_l2cache_avl;
 235 
 236 kmem_cache_t *spa_buffer_pool;
 237 int spa_mode_global;
 238 
 239 #ifdef ZFS_DEBUG
 240 /* Everything except dprintf and spa is on by default in debug builds */
 241 int zfs_flags = ~(ZFS_DEBUG_DPRINTF | ZFS_DEBUG_SPA);
 242 #else
 243 int zfs_flags = 0;
 244 #endif
 245 
 246 /*
 247  * zfs_recover can be set to nonzero to attempt to recover from
 248  * otherwise-fatal errors, typically caused by on-disk corruption.  When
 249  * set, calls to zfs_panic_recover() will turn into warning messages.
 250  * This should only be used as a last resort, as it typically results
 251  * in leaked space, or worse.
 252  */
 253 boolean_t zfs_recover = B_FALSE;
 254 
 255 /*
 256  * If destroy encounters an EIO while reading metadata (e.g. indirect
 257  * blocks), space referenced by the missing metadata can not be freed.
 258  * Normally this causes the background destroy to become "stalled", as
 259  * it is unable to make forward progress.  While in this stalled state,
 260  * all remaining space to free from the error-encountering filesystem is
 261  * "temporarily leaked".  Set this flag to cause it to ignore the EIO,
 262  * permanently leak the space from indirect blocks that can not be read,
 263  * and continue to free everything else that it can.
 264  *
 265  * The default, "stalling" behavior is useful if the storage partially
 266  * fails (i.e. some but not all i/os fail), and then later recovers.  In
 267  * this case, we will be able to continue pool operations while it is
 268  * partially failed, and when it recovers, we can continue to free the
 269  * space, with no leaks.  However, note that this case is actually
 270  * fairly rare.
 271  *
 272  * Typically pools either (a) fail completely (but perhaps temporarily,
 273  * e.g. a top-level vdev going offline), or (b) have localized,
 274  * permanent errors (e.g. disk returns the wrong data due to bit flip or
 275  * firmware bug).  In case (a), this setting does not matter because the
 276  * pool will be suspended and the sync thread will not be able to make
 277  * forward progress regardless.  In case (b), because the error is
 278  * permanent, the best we can do is leak the minimum amount of space,
 279  * which is what setting this flag will do.  Therefore, it is reasonable
 280  * for this flag to normally be set, but we chose the more conservative
 281  * approach of not setting it, so that there is no possibility of
 282  * leaking space in the "partial temporary" failure case.
 283  */
 284 boolean_t zfs_free_leak_on_eio = B_FALSE;
 285 
 286 /*
 287  * Expiration time in milliseconds. This value has two meanings. First it is
 288  * used to determine when the spa_deadman() logic should fire. By default the
 289  * spa_deadman() will fire if spa_sync() has not completed in 1000 seconds.
 290  * Secondly, the value determines if an I/O is considered "hung". Any I/O that
 291  * has not completed in zfs_deadman_synctime_ms is considered "hung" resulting
 292  * in a system panic.
 293  */
 294 uint64_t zfs_deadman_synctime_ms = 1000000ULL;
 295 
 296 /*
 297  * Check time in milliseconds. This defines the frequency at which we check
 298  * for hung I/O.
 299  */
 300 uint64_t zfs_deadman_checktime_ms = 5000ULL;
 301 
 302 /*
 303  * Override the zfs deadman behavior via /etc/system. By default the
 304  * deadman is enabled except on VMware and sparc deployments.
 305  */
 306 int zfs_deadman_enabled = -1;
 307 
 308 /*
 309  * The worst case is single-sector max-parity RAID-Z blocks, in which
 310  * case the space requirement is exactly (VDEV_RAIDZ_MAXPARITY + 1)
 311  * times the size; so just assume that.  Add to this the fact that
 312  * we can have up to 3 DVAs per bp, and one more factor of 2 because
 313  * the block may be dittoed with up to 3 DVAs by ddt_sync().  All together,
 314  * the worst case is:
 315  *     (VDEV_RAIDZ_MAXPARITY + 1) * SPA_DVAS_PER_BP * 2 == 24
 316  */
 317 int spa_asize_inflation = 24;
 318 
 319 /*
 320  * ==========================================================================
 321  * SPA config locking
 322  * ==========================================================================
 323  */
 324 static void
 325 spa_config_lock_init(spa_t *spa)
 326 {
 327         for (int i = 0; i < SCL_LOCKS; i++) {
 328                 spa_config_lock_t *scl = &spa->spa_config_lock[i];
 329                 mutex_init(&scl->scl_lock, NULL, MUTEX_DEFAULT, NULL);
 330                 cv_init(&scl->scl_cv, NULL, CV_DEFAULT, NULL);
 331                 refcount_create_untracked(&scl->scl_count);
 332                 scl->scl_writer = NULL;
 333                 scl->scl_write_wanted = 0;
 334         }
 335 }
 336 
 337 static void
 338 spa_config_lock_destroy(spa_t *spa)
 339 {
 340         for (int i = 0; i < SCL_LOCKS; i++) {
 341                 spa_config_lock_t *scl = &spa->spa_config_lock[i];
 342                 mutex_destroy(&scl->scl_lock);
 343                 cv_destroy(&scl->scl_cv);
 344                 refcount_destroy(&scl->scl_count);
 345                 ASSERT(scl->scl_writer == NULL);
 346                 ASSERT(scl->scl_write_wanted == 0);
 347         }
 348 }
 349 
 350 int
 351 spa_config_tryenter(spa_t *spa, int locks, void *tag, krw_t rw)
 352 {
 353         for (int i = 0; i < SCL_LOCKS; i++) {
 354                 spa_config_lock_t *scl = &spa->spa_config_lock[i];
 355                 if (!(locks & (1 << i)))
 356                         continue;
 357                 mutex_enter(&scl->scl_lock);
 358                 if (rw == RW_READER) {
 359                         if (scl->scl_writer || scl->scl_write_wanted) {
 360                                 mutex_exit(&scl->scl_lock);
 361                                 spa_config_exit(spa, locks ^ (1 << i), tag);
 362                                 return (0);
 363                         }
 364                 } else {
 365                         ASSERT(scl->scl_writer != curthread);
 366                         if (!refcount_is_zero(&scl->scl_count)) {
 367                                 mutex_exit(&scl->scl_lock);
 368                                 spa_config_exit(spa, locks ^ (1 << i), tag);
 369                                 return (0);
 370                         }
 371                         scl->scl_writer = curthread;
 372                 }
 373                 (void) refcount_add(&scl->scl_count, tag);
 374                 mutex_exit(&scl->scl_lock);
 375         }
 376         return (1);
 377 }
 378 
 379 void
 380 spa_config_enter(spa_t *spa, int locks, void *tag, krw_t rw)
 381 {
 382         int wlocks_held = 0;
 383 
 384         ASSERT3U(SCL_LOCKS, <, sizeof (wlocks_held) * NBBY);
 385 
 386         for (int i = 0; i < SCL_LOCKS; i++) {
 387                 spa_config_lock_t *scl = &spa->spa_config_lock[i];
 388                 if (scl->scl_writer == curthread)
 389                         wlocks_held |= (1 << i);
 390                 if (!(locks & (1 << i)))
 391                         continue;
 392                 mutex_enter(&scl->scl_lock);
 393                 if (rw == RW_READER) {
 394                         while (scl->scl_writer || scl->scl_write_wanted) {
 395                                 cv_wait(&scl->scl_cv, &scl->scl_lock);
 396                         }
 397                 } else {
 398                         ASSERT(scl->scl_writer != curthread);
 399                         while (!refcount_is_zero(&scl->scl_count)) {
 400                                 scl->scl_write_wanted++;
 401                                 cv_wait(&scl->scl_cv, &scl->scl_lock);
 402                                 scl->scl_write_wanted--;
 403                         }
 404                         scl->scl_writer = curthread;
 405                 }
 406                 (void) refcount_add(&scl->scl_count, tag);
 407                 mutex_exit(&scl->scl_lock);
 408         }
 409         ASSERT(wlocks_held <= locks);
 410 }
 411 
 412 void
 413 spa_config_exit(spa_t *spa, int locks, void *tag)
 414 {
 415         for (int i = SCL_LOCKS - 1; i >= 0; i--) {
 416                 spa_config_lock_t *scl = &spa->spa_config_lock[i];
 417                 if (!(locks & (1 << i)))
 418                         continue;
 419                 mutex_enter(&scl->scl_lock);
 420                 ASSERT(!refcount_is_zero(&scl->scl_count));
 421                 if (refcount_remove(&scl->scl_count, tag) == 0) {
 422                         ASSERT(scl->scl_writer == NULL ||
 423                             scl->scl_writer == curthread);
 424                         scl->scl_writer = NULL;      /* OK in either case */
 425                         cv_broadcast(&scl->scl_cv);
 426                 }
 427                 mutex_exit(&scl->scl_lock);
 428         }
 429 }
 430 
 431 int
 432 spa_config_held(spa_t *spa, int locks, krw_t rw)
 433 {
 434         int locks_held = 0;
 435 
 436         for (int i = 0; i < SCL_LOCKS; i++) {
 437                 spa_config_lock_t *scl = &spa->spa_config_lock[i];
 438                 if (!(locks & (1 << i)))
 439                         continue;
 440                 if ((rw == RW_READER && !refcount_is_zero(&scl->scl_count)) ||
 441                     (rw == RW_WRITER && scl->scl_writer == curthread))
 442                         locks_held |= 1 << i;
 443         }
 444 
 445         return (locks_held);
 446 }
 447 
 448 /*
 449  * ==========================================================================
 450  * SPA namespace functions
 451  * ==========================================================================
 452  */
 453 
 454 /*
 455  * Lookup the named spa_t in the AVL tree.  The spa_namespace_lock must be held.
 456  * Returns NULL if no matching spa_t is found.
 457  */
 458 spa_t *
 459 spa_lookup(const char *name)
 460 {
 461         spa_t *search;
 462         spa_t *spa;
 463         avl_index_t where;
 464         char *cp;
 465 
 466         search = kmem_alloc(sizeof(*search), KM_SLEEP);
 467 
 468         (void) strlcpy(search->spa_name, name, sizeof (search->spa_name));
 469 
 470         /*
 471          * If it's a full dataset name, figure out the pool name and
 472          * just use that.
 473          */
 474         cp = strpbrk(search->spa_name, "/@#");
 475         if (cp != NULL)
 476                 *cp = '\0';
 477 
 478         spa = avl_find(&spa_namespace_avl, search, &where);
 479         kmem_free(search, sizeof(*search));
 480 
 481         return (spa);
 482 }
 483 
 484 /*
 485  * Fires when spa_sync has not completed within zfs_deadman_synctime_ms.
 486  * If the zfs_deadman_enabled flag is set then it inspects all vdev queues
 487  * looking for potentially hung I/Os.
 488  */
 489 void
 490 spa_deadman(void *arg)
 491 {
 492         spa_t *spa = arg;
 493 
 494         /*
 495          * Disable the deadman timer if the pool is suspended.
 496          */
 497         if (spa_suspended(spa)) {
 498                 VERIFY(cyclic_reprogram(spa->spa_deadman_cycid, CY_INFINITY));
 499                 return;
 500         }
 501 
 502         zfs_dbgmsg("slow spa_sync: started %llu seconds ago, calls %llu",
 503             (gethrtime() - spa->spa_sync_starttime) / NANOSEC,
 504             ++spa->spa_deadman_calls);
 505         if (zfs_deadman_enabled)
 506                 vdev_deadman(spa->spa_root_vdev);
 507 }
 508 
 509 /*
 510  * Create an uninitialized spa_t with the given name.  Requires
 511  * spa_namespace_lock.  The caller must ensure that the spa_t doesn't already
 512  * exist by calling spa_lookup() first.
 513  */
 514 spa_t *
 515 spa_add(const char *name, nvlist_t *config, const char *altroot)
 516 {
 517         spa_t *spa;
 518         spa_config_dirent_t *dp;
 519         cyc_handler_t hdlr;
 520         cyc_time_t when;
 521 
 522         ASSERT(MUTEX_HELD(&spa_namespace_lock));
 523 
 524         spa = kmem_zalloc(sizeof (spa_t), KM_SLEEP);
 525 
 526         mutex_init(&spa->spa_async_lock, NULL, MUTEX_DEFAULT, NULL);
 527         mutex_init(&spa->spa_errlist_lock, NULL, MUTEX_DEFAULT, NULL);
 528         mutex_init(&spa->spa_errlog_lock, NULL, MUTEX_DEFAULT, NULL);
 529         mutex_init(&spa->spa_history_lock, NULL, MUTEX_DEFAULT, NULL);
 530         mutex_init(&spa->spa_proc_lock, NULL, MUTEX_DEFAULT, NULL);
 531         mutex_init(&spa->spa_props_lock, NULL, MUTEX_DEFAULT, NULL);
 532         mutex_init(&spa->spa_scrub_lock, NULL, MUTEX_DEFAULT, NULL);
 533         mutex_init(&spa->spa_suspend_lock, NULL, MUTEX_DEFAULT, NULL);
 534         mutex_init(&spa->spa_vdev_top_lock, NULL, MUTEX_DEFAULT, NULL);
 535         mutex_init(&spa->spa_iokstat_lock, NULL, MUTEX_DEFAULT, NULL);
 536 
 537         cv_init(&spa->spa_async_cv, NULL, CV_DEFAULT, NULL);
 538         cv_init(&spa->spa_proc_cv, NULL, CV_DEFAULT, NULL);
 539         cv_init(&spa->spa_scrub_io_cv, NULL, CV_DEFAULT, NULL);
 540         cv_init(&spa->spa_suspend_cv, NULL, CV_DEFAULT, NULL);
 541 
 542         for (int t = 0; t < TXG_SIZE; t++)
 543                 bplist_create(&spa->spa_free_bplist[t]);
 544 
 545         (void) strlcpy(spa->spa_name, name, sizeof (spa->spa_name));
 546         spa->spa_state = POOL_STATE_UNINITIALIZED;
 547         spa->spa_freeze_txg = UINT64_MAX;
 548         spa->spa_final_txg = UINT64_MAX;
 549         spa->spa_load_max_txg = UINT64_MAX;
 550         spa->spa_proc = &p0;
 551         spa->spa_proc_state = SPA_PROC_NONE;
 552 
 553         hdlr.cyh_func = spa_deadman;
 554         hdlr.cyh_arg = spa;
 555         hdlr.cyh_level = CY_LOW_LEVEL;
 556 
 557         spa->spa_deadman_synctime = MSEC2NSEC(zfs_deadman_synctime_ms);
 558 
 559         /*
 560          * This determines how often we need to check for hung I/Os after
 561          * the cyclic has already fired. Since checking for hung I/Os is
 562          * an expensive operation we don't want to check too frequently.
 563          * Instead wait for 5 seconds before checking again.
 564          */
 565         when.cyt_interval = MSEC2NSEC(zfs_deadman_checktime_ms);
 566         when.cyt_when = CY_INFINITY;
 567         mutex_enter(&cpu_lock);
 568         spa->spa_deadman_cycid = cyclic_add(&hdlr, &when);
 569         mutex_exit(&cpu_lock);
 570 
 571         refcount_create(&spa->spa_refcount);
 572         spa_config_lock_init(spa);
 573 
 574         avl_add(&spa_namespace_avl, spa);
 575 
 576         /*
 577          * Set the alternate root, if there is one.
 578          */
 579         if (altroot) {
 580                 spa->spa_root = spa_strdup(altroot);
 581                 spa_active_count++;
 582         }
 583 
 584         /*
 585          * Every pool starts with the default cachefile
 586          */
 587         list_create(&spa->spa_config_list, sizeof (spa_config_dirent_t),
 588             offsetof(spa_config_dirent_t, scd_link));
 589 
 590         dp = kmem_zalloc(sizeof (spa_config_dirent_t), KM_SLEEP);
 591         dp->scd_path = altroot ? NULL : spa_strdup(spa_config_path);
 592         list_insert_head(&spa->spa_config_list, dp);
 593 
 594         VERIFY(nvlist_alloc(&spa->spa_load_info, NV_UNIQUE_NAME,
 595             KM_SLEEP) == 0);
 596 
 597         if (config != NULL) {
 598                 nvlist_t *features;
 599 
 600                 if (nvlist_lookup_nvlist(config, ZPOOL_CONFIG_FEATURES_FOR_READ,
 601                     &features) == 0) {
 602                         VERIFY(nvlist_dup(features, &spa->spa_label_features,
 603                             0) == 0);
 604                 }
 605 
 606                 VERIFY(nvlist_dup(config, &spa->spa_config, 0) == 0);
 607         }
 608 
 609         if (spa->spa_label_features == NULL) {
 610                 VERIFY(nvlist_alloc(&spa->spa_label_features, NV_UNIQUE_NAME,
 611                     KM_SLEEP) == 0);
 612         }
 613 
 614         spa->spa_iokstat = kstat_create("zfs", 0, name,
 615             "disk", KSTAT_TYPE_IO, 1, 0);
 616         if (spa->spa_iokstat) {
 617                 spa->spa_iokstat->ks_lock = &spa->spa_iokstat_lock;
 618                 kstat_install(spa->spa_iokstat);
 619         }
 620 
 621         spa->spa_debug = ((zfs_flags & ZFS_DEBUG_SPA) != 0);
 622 
 623         /*
 624          * As a pool is being created, treat all features as disabled by
 625          * setting SPA_FEATURE_DISABLED for all entries in the feature
 626          * refcount cache.
 627          */
 628         for (int i = 0; i < SPA_FEATURES; i++) {
 629                 spa->spa_feat_refcount_cache[i] = SPA_FEATURE_DISABLED;
 630         }
 631 
 632         return (spa);
 633 }
 634 
 635 /*
 636  * Removes a spa_t from the namespace, freeing up any memory used.  Requires
 637  * spa_namespace_lock.  This is called only after the spa_t has been closed and
 638  * deactivated.
 639  */
 640 void
 641 spa_remove(spa_t *spa)
 642 {
 643         spa_config_dirent_t *dp;
 644 
 645         ASSERT(MUTEX_HELD(&spa_namespace_lock));
 646         ASSERT(spa->spa_state == POOL_STATE_UNINITIALIZED);
 647 
 648         nvlist_free(spa->spa_config_splitting);
 649 
 650         avl_remove(&spa_namespace_avl, spa);
 651         cv_broadcast(&spa_namespace_cv);
 652 
 653         if (spa->spa_root) {
 654                 spa_strfree(spa->spa_root);
 655                 spa_active_count--;
 656         }
 657 
 658         while ((dp = list_head(&spa->spa_config_list)) != NULL) {
 659                 list_remove(&spa->spa_config_list, dp);
 660                 if (dp->scd_path != NULL)
 661                         spa_strfree(dp->scd_path);
 662                 kmem_free(dp, sizeof (spa_config_dirent_t));
 663         }
 664 
 665         list_destroy(&spa->spa_config_list);
 666 
 667         nvlist_free(spa->spa_label_features);
 668         nvlist_free(spa->spa_load_info);
 669         spa_config_set(spa, NULL);
 670 
 671         mutex_enter(&cpu_lock);
 672         if (spa->spa_deadman_cycid != CYCLIC_NONE)
 673                 cyclic_remove(spa->spa_deadman_cycid);
 674         mutex_exit(&cpu_lock);
 675         spa->spa_deadman_cycid = CYCLIC_NONE;
 676 
 677         refcount_destroy(&spa->spa_refcount);
 678 
 679         spa_config_lock_destroy(spa);
 680 
 681         kstat_delete(spa->spa_iokstat);
 682         spa->spa_iokstat = NULL;
 683 
 684         for (int t = 0; t < TXG_SIZE; t++)
 685                 bplist_destroy(&spa->spa_free_bplist[t]);
 686 
 687         cv_destroy(&spa->spa_async_cv);
 688         cv_destroy(&spa->spa_proc_cv);
 689         cv_destroy(&spa->spa_scrub_io_cv);
 690         cv_destroy(&spa->spa_suspend_cv);
 691 
 692         mutex_destroy(&spa->spa_async_lock);
 693         mutex_destroy(&spa->spa_errlist_lock);
 694         mutex_destroy(&spa->spa_errlog_lock);
 695         mutex_destroy(&spa->spa_history_lock);
 696         mutex_destroy(&spa->spa_proc_lock);
 697         mutex_destroy(&spa->spa_props_lock);
 698         mutex_destroy(&spa->spa_scrub_lock);
 699         mutex_destroy(&spa->spa_suspend_lock);
 700         mutex_destroy(&spa->spa_vdev_top_lock);
 701         mutex_destroy(&spa->spa_iokstat_lock);
 702 
 703         kmem_free(spa, sizeof (spa_t));
 704 }
 705 
 706 /*
 707  * Given a pool, return the next pool in the namespace, or NULL if there is
 708  * none.  If 'prev' is NULL, return the first pool.
 709  */
 710 spa_t *
 711 spa_next(spa_t *prev)
 712 {
 713         ASSERT(MUTEX_HELD(&spa_namespace_lock));
 714 
 715         if (prev)
 716                 return (AVL_NEXT(&spa_namespace_avl, prev));
 717         else
 718                 return (avl_first(&spa_namespace_avl));
 719 }
 720 
 721 /*
 722  * ==========================================================================
 723  * SPA refcount functions
 724  * ==========================================================================
 725  */
 726 
 727 /*
 728  * Add a reference to the given spa_t.  Must have at least one reference, or
 729  * have the namespace lock held.
 730  */
 731 void
 732 spa_open_ref(spa_t *spa, void *tag)
 733 {
 734         ASSERT(refcount_count(&spa->spa_refcount) >= spa->spa_minref ||
 735             MUTEX_HELD(&spa_namespace_lock));
 736         (void) refcount_add(&spa->spa_refcount, tag);
 737 }
 738 
 739 /*
 740  * Remove a reference to the given spa_t.  Must have at least one reference, or
 741  * have the namespace lock held.
 742  */
 743 void
 744 spa_close(spa_t *spa, void *tag)
 745 {
 746         ASSERT(refcount_count(&spa->spa_refcount) > spa->spa_minref ||
 747             MUTEX_HELD(&spa_namespace_lock));
 748         (void) refcount_remove(&spa->spa_refcount, tag);
 749 }
 750 
 751 /*
 752  * Check to see if the spa refcount is zero.  Must be called with
 753  * spa_namespace_lock held.  We really compare against spa_minref, which is the
 754  * number of references acquired when opening a pool
 755  */
 756 boolean_t
 757 spa_refcount_zero(spa_t *spa)
 758 {
 759         ASSERT(MUTEX_HELD(&spa_namespace_lock));
 760 
 761         return (refcount_count(&spa->spa_refcount) == spa->spa_minref);
 762 }
 763 
 764 /*
 765  * ==========================================================================
 766  * SPA spare and l2cache tracking
 767  * ==========================================================================
 768  */
 769 
 770 /*
 771  * Hot spares and cache devices are tracked using the same code below,
 772  * for 'auxiliary' devices.
 773  */
 774 
 775 typedef struct spa_aux {
 776         uint64_t        aux_guid;
 777         uint64_t        aux_pool;
 778         avl_node_t      aux_avl;
 779         int             aux_count;
 780 } spa_aux_t;
 781 
 782 static int
 783 spa_aux_compare(const void *a, const void *b)
 784 {
 785         const spa_aux_t *sa = a;
 786         const spa_aux_t *sb = b;
 787 
 788         if (sa->aux_guid < sb->aux_guid)
 789                 return (-1);
 790         else if (sa->aux_guid > sb->aux_guid)
 791                 return (1);
 792         else
 793                 return (0);
 794 }
 795 
 796 void
 797 spa_aux_add(vdev_t *vd, avl_tree_t *avl)
 798 {
 799         avl_index_t where;
 800         spa_aux_t search;
 801         spa_aux_t *aux;
 802 
 803         search.aux_guid = vd->vdev_guid;
 804         if ((aux = avl_find(avl, &search, &where)) != NULL) {
 805                 aux->aux_count++;
 806         } else {
 807                 aux = kmem_zalloc(sizeof (spa_aux_t), KM_SLEEP);
 808                 aux->aux_guid = vd->vdev_guid;
 809                 aux->aux_count = 1;
 810                 avl_insert(avl, aux, where);
 811         }
 812 }
 813 
 814 void
 815 spa_aux_remove(vdev_t *vd, avl_tree_t *avl)
 816 {
 817         spa_aux_t search;
 818         spa_aux_t *aux;
 819         avl_index_t where;
 820 
 821         search.aux_guid = vd->vdev_guid;
 822         aux = avl_find(avl, &search, &where);
 823 
 824         ASSERT(aux != NULL);
 825 
 826         if (--aux->aux_count == 0) {
 827                 avl_remove(avl, aux);
 828                 kmem_free(aux, sizeof (spa_aux_t));
 829         } else if (aux->aux_pool == spa_guid(vd->vdev_spa)) {
 830                 aux->aux_pool = 0ULL;
 831         }
 832 }
 833 
 834 boolean_t
 835 spa_aux_exists(uint64_t guid, uint64_t *pool, int *refcnt, avl_tree_t *avl)
 836 {
 837         spa_aux_t search, *found;
 838 
 839         search.aux_guid = guid;
 840         found = avl_find(avl, &search, NULL);
 841 
 842         if (pool) {
 843                 if (found)
 844                         *pool = found->aux_pool;
 845                 else
 846                         *pool = 0ULL;
 847         }
 848 
 849         if (refcnt) {
 850                 if (found)
 851                         *refcnt = found->aux_count;
 852                 else
 853                         *refcnt = 0;
 854         }
 855 
 856         return (found != NULL);
 857 }
 858 
 859 void
 860 spa_aux_activate(vdev_t *vd, avl_tree_t *avl)
 861 {
 862         spa_aux_t search, *found;
 863         avl_index_t where;
 864 
 865         search.aux_guid = vd->vdev_guid;
 866         found = avl_find(avl, &search, &where);
 867         ASSERT(found != NULL);
 868         ASSERT(found->aux_pool == 0ULL);
 869 
 870         found->aux_pool = spa_guid(vd->vdev_spa);
 871 }
 872 
 873 /*
 874  * Spares are tracked globally due to the following constraints:
 875  *
 876  *      - A spare may be part of multiple pools.
 877  *      - A spare may be added to a pool even if it's actively in use within
 878  *        another pool.
 879  *      - A spare in use in any pool can only be the source of a replacement if
 880  *        the target is a spare in the same pool.
 881  *
 882  * We keep track of all spares on the system through the use of a reference
 883  * counted AVL tree.  When a vdev is added as a spare, or used as a replacement
 884  * spare, then we bump the reference count in the AVL tree.  In addition, we set
 885  * the 'vdev_isspare' member to indicate that the device is a spare (active or
 886  * inactive).  When a spare is made active (used to replace a device in the
 887  * pool), we also keep track of which pool its been made a part of.
 888  *
 889  * The 'spa_spare_lock' protects the AVL tree.  These functions are normally
 890  * called under the spa_namespace lock as part of vdev reconfiguration.  The
 891  * separate spare lock exists for the status query path, which does not need to
 892  * be completely consistent with respect to other vdev configuration changes.
 893  */
 894 
 895 static int
 896 spa_spare_compare(const void *a, const void *b)
 897 {
 898         return (spa_aux_compare(a, b));
 899 }
 900 
 901 void
 902 spa_spare_add(vdev_t *vd)
 903 {
 904         mutex_enter(&spa_spare_lock);
 905         ASSERT(!vd->vdev_isspare);
 906         spa_aux_add(vd, &spa_spare_avl);
 907         vd->vdev_isspare = B_TRUE;
 908         mutex_exit(&spa_spare_lock);
 909 }
 910 
 911 void
 912 spa_spare_remove(vdev_t *vd)
 913 {
 914         mutex_enter(&spa_spare_lock);
 915         ASSERT(vd->vdev_isspare);
 916         spa_aux_remove(vd, &spa_spare_avl);
 917         vd->vdev_isspare = B_FALSE;
 918         mutex_exit(&spa_spare_lock);
 919 }
 920 
 921 boolean_t
 922 spa_spare_exists(uint64_t guid, uint64_t *pool, int *refcnt)
 923 {
 924         boolean_t found;
 925 
 926         mutex_enter(&spa_spare_lock);
 927         found = spa_aux_exists(guid, pool, refcnt, &spa_spare_avl);
 928         mutex_exit(&spa_spare_lock);
 929 
 930         return (found);
 931 }
 932 
 933 void
 934 spa_spare_activate(vdev_t *vd)
 935 {
 936         mutex_enter(&spa_spare_lock);
 937         ASSERT(vd->vdev_isspare);
 938         spa_aux_activate(vd, &spa_spare_avl);
 939         mutex_exit(&spa_spare_lock);
 940 }
 941 
 942 /*
 943  * Level 2 ARC devices are tracked globally for the same reasons as spares.
 944  * Cache devices currently only support one pool per cache device, and so
 945  * for these devices the aux reference count is currently unused beyond 1.
 946  */
 947 
 948 static int
 949 spa_l2cache_compare(const void *a, const void *b)
 950 {
 951         return (spa_aux_compare(a, b));
 952 }
 953 
 954 void
 955 spa_l2cache_add(vdev_t *vd)
 956 {
 957         mutex_enter(&spa_l2cache_lock);
 958         ASSERT(!vd->vdev_isl2cache);
 959         spa_aux_add(vd, &spa_l2cache_avl);
 960         vd->vdev_isl2cache = B_TRUE;
 961         mutex_exit(&spa_l2cache_lock);
 962 }
 963 
 964 void
 965 spa_l2cache_remove(vdev_t *vd)
 966 {
 967         mutex_enter(&spa_l2cache_lock);
 968         ASSERT(vd->vdev_isl2cache);
 969         spa_aux_remove(vd, &spa_l2cache_avl);
 970         vd->vdev_isl2cache = B_FALSE;
 971         mutex_exit(&spa_l2cache_lock);
 972 }
 973 
 974 boolean_t
 975 spa_l2cache_exists(uint64_t guid, uint64_t *pool)
 976 {
 977         boolean_t found;
 978 
 979         mutex_enter(&spa_l2cache_lock);
 980         found = spa_aux_exists(guid, pool, NULL, &spa_l2cache_avl);
 981         mutex_exit(&spa_l2cache_lock);
 982 
 983         return (found);
 984 }
 985 
 986 void
 987 spa_l2cache_activate(vdev_t *vd)
 988 {
 989         mutex_enter(&spa_l2cache_lock);
 990         ASSERT(vd->vdev_isl2cache);
 991         spa_aux_activate(vd, &spa_l2cache_avl);
 992         mutex_exit(&spa_l2cache_lock);
 993 }
 994 
 995 /*
 996  * ==========================================================================
 997  * SPA vdev locking
 998  * ==========================================================================
 999  */
1000 
1001 /*
1002  * Lock the given spa_t for the purpose of adding or removing a vdev.
1003  * Grabs the global spa_namespace_lock plus the spa config lock for writing.
1004  * It returns the next transaction group for the spa_t.
1005  */
1006 uint64_t
1007 spa_vdev_enter(spa_t *spa)
1008 {
1009         mutex_enter(&spa->spa_vdev_top_lock);
1010         mutex_enter(&spa_namespace_lock);
1011         return (spa_vdev_config_enter(spa));
1012 }
1013 
1014 /*
1015  * Internal implementation for spa_vdev_enter().  Used when a vdev
1016  * operation requires multiple syncs (i.e. removing a device) while
1017  * keeping the spa_namespace_lock held.
1018  */
1019 uint64_t
1020 spa_vdev_config_enter(spa_t *spa)
1021 {
1022         ASSERT(MUTEX_HELD(&spa_namespace_lock));
1023 
1024         spa_config_enter(spa, SCL_ALL, spa, RW_WRITER);
1025 
1026         return (spa_last_synced_txg(spa) + 1);
1027 }
1028 
1029 /*
1030  * Used in combination with spa_vdev_config_enter() to allow the syncing
1031  * of multiple transactions without releasing the spa_namespace_lock.
1032  */
1033 void
1034 spa_vdev_config_exit(spa_t *spa, vdev_t *vd, uint64_t txg, int error, char *tag)
1035 {
1036         ASSERT(MUTEX_HELD(&spa_namespace_lock));
1037 
1038         int config_changed = B_FALSE;
1039 
1040         ASSERT(txg > spa_last_synced_txg(spa));
1041 
1042         spa->spa_pending_vdev = NULL;
1043 
1044         /*
1045          * Reassess the DTLs.
1046          */
1047         vdev_dtl_reassess(spa->spa_root_vdev, 0, 0, B_FALSE);
1048 
1049         if (error == 0 && !list_is_empty(&spa->spa_config_dirty_list)) {
1050                 config_changed = B_TRUE;
1051                 spa->spa_config_generation++;
1052         }
1053 
1054         /*
1055          * Verify the metaslab classes.
1056          */
1057         ASSERT(metaslab_class_validate(spa_normal_class(spa)) == 0);
1058         ASSERT(metaslab_class_validate(spa_log_class(spa)) == 0);
1059 
1060         spa_config_exit(spa, SCL_ALL, spa);
1061 
1062         /*
1063          * Panic the system if the specified tag requires it.  This
1064          * is useful for ensuring that configurations are updated
1065          * transactionally.
1066          */
1067         if (zio_injection_enabled)
1068                 zio_handle_panic_injection(spa, tag, 0);
1069 
1070         /*
1071          * Note: this txg_wait_synced() is important because it ensures
1072          * that there won't be more than one config change per txg.
1073          * This allows us to use the txg as the generation number.
1074          */
1075         if (error == 0)
1076                 txg_wait_synced(spa->spa_dsl_pool, txg);
1077 
1078         if (vd != NULL) {
1079                 ASSERT(!vd->vdev_detached || vd->vdev_dtl_sm == NULL);
1080                 spa_config_enter(spa, SCL_ALL, spa, RW_WRITER);
1081                 vdev_free(vd);
1082                 spa_config_exit(spa, SCL_ALL, spa);
1083         }
1084 
1085         /*
1086          * If the config changed, update the config cache.
1087          */
1088         if (config_changed)
1089                 spa_config_sync(spa, B_FALSE, B_TRUE);
1090 }
1091 
1092 /*
1093  * Unlock the spa_t after adding or removing a vdev.  Besides undoing the
1094  * locking of spa_vdev_enter(), we also want make sure the transactions have
1095  * synced to disk, and then update the global configuration cache with the new
1096  * information.
1097  */
1098 int
1099 spa_vdev_exit(spa_t *spa, vdev_t *vd, uint64_t txg, int error)
1100 {
1101         spa_vdev_config_exit(spa, vd, txg, error, FTAG);
1102         mutex_exit(&spa_namespace_lock);
1103         mutex_exit(&spa->spa_vdev_top_lock);
1104 
1105         return (error);
1106 }
1107 
1108 /*
1109  * Lock the given spa_t for the purpose of changing vdev state.
1110  */
1111 void
1112 spa_vdev_state_enter(spa_t *spa, int oplocks)
1113 {
1114         int locks = SCL_STATE_ALL | oplocks;
1115 
1116         /*
1117          * Root pools may need to read of the underlying devfs filesystem
1118          * when opening up a vdev.  Unfortunately if we're holding the
1119          * SCL_ZIO lock it will result in a deadlock when we try to issue
1120          * the read from the root filesystem.  Instead we "prefetch"
1121          * the associated vnodes that we need prior to opening the
1122          * underlying devices and cache them so that we can prevent
1123          * any I/O when we are doing the actual open.
1124          */
1125         if (spa_is_root(spa)) {
1126                 int low = locks & ~(SCL_ZIO - 1);
1127                 int high = locks & ~low;
1128 
1129                 spa_config_enter(spa, high, spa, RW_WRITER);
1130                 vdev_hold(spa->spa_root_vdev);
1131                 spa_config_enter(spa, low, spa, RW_WRITER);
1132         } else {
1133                 spa_config_enter(spa, locks, spa, RW_WRITER);
1134         }
1135         spa->spa_vdev_locks = locks;
1136 }
1137 
1138 int
1139 spa_vdev_state_exit(spa_t *spa, vdev_t *vd, int error)
1140 {
1141         boolean_t config_changed = B_FALSE;
1142 
1143         if (vd != NULL || error == 0)
1144                 vdev_dtl_reassess(vd ? vd->vdev_top : spa->spa_root_vdev,
1145                     0, 0, B_FALSE);
1146 
1147         if (vd != NULL) {
1148                 vdev_state_dirty(vd->vdev_top);
1149                 config_changed = B_TRUE;
1150                 spa->spa_config_generation++;
1151         }
1152 
1153         if (spa_is_root(spa))
1154                 vdev_rele(spa->spa_root_vdev);
1155 
1156         ASSERT3U(spa->spa_vdev_locks, >=, SCL_STATE_ALL);
1157         spa_config_exit(spa, spa->spa_vdev_locks, spa);
1158 
1159         /*
1160          * If anything changed, wait for it to sync.  This ensures that,
1161          * from the system administrator's perspective, zpool(1M) commands
1162          * are synchronous.  This is important for things like zpool offline:
1163          * when the command completes, you expect no further I/O from ZFS.
1164          */
1165         if (vd != NULL)
1166                 txg_wait_synced(spa->spa_dsl_pool, 0);
1167 
1168         /*
1169          * If the config changed, update the config cache.
1170          */
1171         if (config_changed) {
1172                 mutex_enter(&spa_namespace_lock);
1173                 spa_config_sync(spa, B_FALSE, B_TRUE);
1174                 mutex_exit(&spa_namespace_lock);
1175         }
1176 
1177         return (error);
1178 }
1179 
1180 /*
1181  * ==========================================================================
1182  * Miscellaneous functions
1183  * ==========================================================================
1184  */
1185 
1186 void
1187 spa_activate_mos_feature(spa_t *spa, const char *feature, dmu_tx_t *tx)
1188 {
1189         if (!nvlist_exists(spa->spa_label_features, feature)) {
1190                 fnvlist_add_boolean(spa->spa_label_features, feature);
1191                 /*
1192                  * When we are creating the pool (tx_txg==TXG_INITIAL), we can't
1193                  * dirty the vdev config because lock SCL_CONFIG is not held.
1194                  * Thankfully, in this case we don't need to dirty the config
1195                  * because it will be written out anyway when we finish
1196                  * creating the pool.
1197                  */
1198                 if (tx->tx_txg != TXG_INITIAL)
1199                         vdev_config_dirty(spa->spa_root_vdev);
1200         }
1201 }
1202 
1203 void
1204 spa_deactivate_mos_feature(spa_t *spa, const char *feature)
1205 {
1206         if (nvlist_remove_all(spa->spa_label_features, feature) == 0)
1207                 vdev_config_dirty(spa->spa_root_vdev);
1208 }
1209 
1210 /*
1211  * Rename a spa_t.
1212  */
1213 int
1214 spa_rename(const char *name, const char *newname)
1215 {
1216         spa_t *spa;
1217         int err;
1218 
1219         /*
1220          * Lookup the spa_t and grab the config lock for writing.  We need to
1221          * actually open the pool so that we can sync out the necessary labels.
1222          * It's OK to call spa_open() with the namespace lock held because we
1223          * allow recursive calls for other reasons.
1224          */
1225         mutex_enter(&spa_namespace_lock);
1226         if ((err = spa_open(name, &spa, FTAG)) != 0) {
1227                 mutex_exit(&spa_namespace_lock);
1228                 return (err);
1229         }
1230 
1231         spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
1232 
1233         avl_remove(&spa_namespace_avl, spa);
1234         (void) strlcpy(spa->spa_name, newname, sizeof (spa->spa_name));
1235         avl_add(&spa_namespace_avl, spa);
1236 
1237         /*
1238          * Sync all labels to disk with the new names by marking the root vdev
1239          * dirty and waiting for it to sync.  It will pick up the new pool name
1240          * during the sync.
1241          */
1242         vdev_config_dirty(spa->spa_root_vdev);
1243 
1244         spa_config_exit(spa, SCL_ALL, FTAG);
1245 
1246         txg_wait_synced(spa->spa_dsl_pool, 0);
1247 
1248         /*
1249          * Sync the updated config cache.
1250          */
1251         spa_config_sync(spa, B_FALSE, B_TRUE);
1252 
1253         spa_close(spa, FTAG);
1254 
1255         mutex_exit(&spa_namespace_lock);
1256 
1257         return (0);
1258 }
1259 
1260 /*
1261  * Return the spa_t associated with given pool_guid, if it exists.  If
1262  * device_guid is non-zero, determine whether the pool exists *and* contains
1263  * a device with the specified device_guid.
1264  */
1265 spa_t *
1266 spa_by_guid(uint64_t pool_guid, uint64_t device_guid)
1267 {
1268         spa_t *spa;
1269         avl_tree_t *t = &spa_namespace_avl;
1270 
1271         ASSERT(MUTEX_HELD(&spa_namespace_lock));
1272 
1273         for (spa = avl_first(t); spa != NULL; spa = AVL_NEXT(t, spa)) {
1274                 if (spa->spa_state == POOL_STATE_UNINITIALIZED)
1275                         continue;
1276                 if (spa->spa_root_vdev == NULL)
1277                         continue;
1278                 if (spa_guid(spa) == pool_guid) {
1279                         if (device_guid == 0)
1280                                 break;
1281 
1282                         if (vdev_lookup_by_guid(spa->spa_root_vdev,
1283                             device_guid) != NULL)
1284                                 break;
1285 
1286                         /*
1287                          * Check any devices we may be in the process of adding.
1288                          */
1289                         if (spa->spa_pending_vdev) {
1290                                 if (vdev_lookup_by_guid(spa->spa_pending_vdev,
1291                                     device_guid) != NULL)
1292                                         break;
1293                         }
1294                 }
1295         }
1296 
1297         return (spa);
1298 }
1299 
1300 /*
1301  * Determine whether a pool with the given pool_guid exists.
1302  */
1303 boolean_t
1304 spa_guid_exists(uint64_t pool_guid, uint64_t device_guid)
1305 {
1306         return (spa_by_guid(pool_guid, device_guid) != NULL);
1307 }
1308 
1309 char *
1310 spa_strdup(const char *s)
1311 {
1312         size_t len;
1313         char *new;
1314 
1315         len = strlen(s);
1316         new = kmem_alloc(len + 1, KM_SLEEP);
1317         bcopy(s, new, len);
1318         new[len] = '\0';
1319 
1320         return (new);
1321 }
1322 
1323 void
1324 spa_strfree(char *s)
1325 {
1326         kmem_free(s, strlen(s) + 1);
1327 }
1328 
1329 uint64_t
1330 spa_get_random(uint64_t range)
1331 {
1332         uint64_t r;
1333 
1334         ASSERT(range != 0);
1335 
1336         (void) random_get_pseudo_bytes((void *)&r, sizeof (uint64_t));
1337 
1338         return (r % range);
1339 }
1340 
1341 uint64_t
1342 spa_generate_guid(spa_t *spa)
1343 {
1344         uint64_t guid = spa_get_random(-1ULL);
1345 
1346         if (spa != NULL) {
1347                 while (guid == 0 || spa_guid_exists(spa_guid(spa), guid))
1348                         guid = spa_get_random(-1ULL);
1349         } else {
1350                 while (guid == 0 || spa_guid_exists(guid, 0))
1351                         guid = spa_get_random(-1ULL);
1352         }
1353 
1354         return (guid);
1355 }
1356 
1357 void
1358 snprintf_blkptr(char *buf, size_t buflen, const blkptr_t *bp)
1359 {
1360         char type[256];
1361         char *checksum = NULL;
1362         char *compress = NULL;
1363 
1364         if (bp != NULL) {
1365                 if (BP_GET_TYPE(bp) & DMU_OT_NEWTYPE) {
1366                         dmu_object_byteswap_t bswap =
1367                             DMU_OT_BYTESWAP(BP_GET_TYPE(bp));
1368                         (void) snprintf(type, sizeof (type), "bswap %s %s",
1369                             DMU_OT_IS_METADATA(BP_GET_TYPE(bp)) ?
1370                             "metadata" : "data",
1371                             dmu_ot_byteswap[bswap].ob_name);
1372                 } else {
1373                         (void) strlcpy(type, dmu_ot[BP_GET_TYPE(bp)].ot_name,
1374                             sizeof (type));
1375                 }
1376                 if (!BP_IS_EMBEDDED(bp)) {
1377                         checksum =
1378                             zio_checksum_table[BP_GET_CHECKSUM(bp)].ci_name;
1379                 }
1380                 compress = zio_compress_table[BP_GET_COMPRESS(bp)].ci_name;
1381         }
1382 
1383         SNPRINTF_BLKPTR(snprintf, ' ', buf, buflen, bp, type, checksum,
1384             compress);
1385 }
1386 
1387 void
1388 spa_freeze(spa_t *spa)
1389 {
1390         uint64_t freeze_txg = 0;
1391 
1392         spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
1393         if (spa->spa_freeze_txg == UINT64_MAX) {
1394                 freeze_txg = spa_last_synced_txg(spa) + TXG_SIZE;
1395                 spa->spa_freeze_txg = freeze_txg;
1396         }
1397         spa_config_exit(spa, SCL_ALL, FTAG);
1398         if (freeze_txg != 0)
1399                 txg_wait_synced(spa_get_dsl(spa), freeze_txg);
1400 }
1401 
1402 void
1403 zfs_panic_recover(const char *fmt, ...)
1404 {
1405         va_list adx;
1406 
1407         va_start(adx, fmt);
1408         vcmn_err(zfs_recover ? CE_WARN : CE_PANIC, fmt, adx);
1409         va_end(adx);
1410 }
1411 
1412 /*
1413  * This is a stripped-down version of strtoull, suitable only for converting
1414  * lowercase hexadecimal numbers that don't overflow.
1415  */
1416 uint64_t
1417 strtonum(const char *str, char **nptr)
1418 {
1419         uint64_t val = 0;
1420         char c;
1421         int digit;
1422 
1423         while ((c = *str) != '\0') {
1424                 if (c >= '0' && c <= '9')
1425                         digit = c - '0';
1426                 else if (c >= 'a' && c <= 'f')
1427                         digit = 10 + c - 'a';
1428                 else
1429                         break;
1430 
1431                 val *= 16;
1432                 val += digit;
1433 
1434                 str++;
1435         }
1436 
1437         if (nptr)
1438                 *nptr = (char *)str;
1439 
1440         return (val);
1441 }
1442 
1443 /*
1444  * ==========================================================================
1445  * Accessor functions
1446  * ==========================================================================
1447  */
1448 
1449 boolean_t
1450 spa_shutting_down(spa_t *spa)
1451 {
1452         return (spa->spa_async_suspended);
1453 }
1454 
1455 dsl_pool_t *
1456 spa_get_dsl(spa_t *spa)
1457 {
1458         return (spa->spa_dsl_pool);
1459 }
1460 
1461 boolean_t
1462 spa_is_initializing(spa_t *spa)
1463 {
1464         return (spa->spa_is_initializing);
1465 }
1466 
1467 blkptr_t *
1468 spa_get_rootblkptr(spa_t *spa)
1469 {
1470         return (&spa->spa_ubsync.ub_rootbp);
1471 }
1472 
1473 void
1474 spa_set_rootblkptr(spa_t *spa, const blkptr_t *bp)
1475 {
1476         spa->spa_uberblock.ub_rootbp = *bp;
1477 }
1478 
1479 void
1480 spa_altroot(spa_t *spa, char *buf, size_t buflen)
1481 {
1482         if (spa->spa_root == NULL)
1483                 buf[0] = '\0';
1484         else
1485                 (void) strncpy(buf, spa->spa_root, buflen);
1486 }
1487 
1488 int
1489 spa_sync_pass(spa_t *spa)
1490 {
1491         return (spa->spa_sync_pass);
1492 }
1493 
1494 char *
1495 spa_name(spa_t *spa)
1496 {
1497         return (spa->spa_name);
1498 }
1499 
1500 uint64_t
1501 spa_guid(spa_t *spa)
1502 {
1503         dsl_pool_t *dp = spa_get_dsl(spa);
1504         uint64_t guid;
1505 
1506         /*
1507          * If we fail to parse the config during spa_load(), we can go through
1508          * the error path (which posts an ereport) and end up here with no root
1509          * vdev.  We stash the original pool guid in 'spa_config_guid' to handle
1510          * this case.
1511          */
1512         if (spa->spa_root_vdev == NULL)
1513                 return (spa->spa_config_guid);
1514 
1515         guid = spa->spa_last_synced_guid != 0 ?
1516             spa->spa_last_synced_guid : spa->spa_root_vdev->vdev_guid;
1517 
1518         /*
1519          * Return the most recently synced out guid unless we're
1520          * in syncing context.
1521          */
1522         if (dp && dsl_pool_sync_context(dp))
1523                 return (spa->spa_root_vdev->vdev_guid);
1524         else
1525                 return (guid);
1526 }
1527 
1528 uint64_t
1529 spa_load_guid(spa_t *spa)
1530 {
1531         /*
1532          * This is a GUID that exists solely as a reference for the
1533          * purposes of the arc.  It is generated at load time, and
1534          * is never written to persistent storage.
1535          */
1536         return (spa->spa_load_guid);
1537 }
1538 
1539 uint64_t
1540 spa_last_synced_txg(spa_t *spa)
1541 {
1542         return (spa->spa_ubsync.ub_txg);
1543 }
1544 
1545 uint64_t
1546 spa_first_txg(spa_t *spa)
1547 {
1548         return (spa->spa_first_txg);
1549 }
1550 
1551 uint64_t
1552 spa_syncing_txg(spa_t *spa)
1553 {
1554         return (spa->spa_syncing_txg);
1555 }
1556 
1557 pool_state_t
1558 spa_state(spa_t *spa)
1559 {
1560         return (spa->spa_state);
1561 }
1562 
1563 spa_load_state_t
1564 spa_load_state(spa_t *spa)
1565 {
1566         return (spa->spa_load_state);
1567 }
1568 
1569 uint64_t
1570 spa_freeze_txg(spa_t *spa)
1571 {
1572         return (spa->spa_freeze_txg);
1573 }
1574 
1575 /* ARGSUSED */
1576 uint64_t
1577 spa_get_asize(spa_t *spa, uint64_t lsize)
1578 {
1579         return (lsize * spa_asize_inflation);
1580 }
1581 
1582 uint64_t
1583 spa_get_dspace(spa_t *spa)
1584 {
1585         return (spa->spa_dspace);
1586 }
1587 
1588 void
1589 spa_update_dspace(spa_t *spa)
1590 {
1591         spa->spa_dspace = metaslab_class_get_dspace(spa_normal_class(spa)) +
1592             ddt_get_dedup_dspace(spa);
1593 }
1594 
1595 /*
1596  * Return the failure mode that has been set to this pool. The default
1597  * behavior will be to block all I/Os when a complete failure occurs.
1598  */
1599 uint8_t
1600 spa_get_failmode(spa_t *spa)
1601 {
1602         return (spa->spa_failmode);
1603 }
1604 
1605 boolean_t
1606 spa_suspended(spa_t *spa)
1607 {
1608         return (spa->spa_suspended);
1609 }
1610 
1611 uint64_t
1612 spa_version(spa_t *spa)
1613 {
1614         return (spa->spa_ubsync.ub_version);
1615 }
1616 
1617 boolean_t
1618 spa_deflate(spa_t *spa)
1619 {
1620         return (spa->spa_deflate);
1621 }
1622 
1623 metaslab_class_t *
1624 spa_normal_class(spa_t *spa)
1625 {
1626         return (spa->spa_normal_class);
1627 }
1628 
1629 metaslab_class_t *
1630 spa_log_class(spa_t *spa)
1631 {
1632         return (spa->spa_log_class);
1633 }
1634 
1635 int
1636 spa_max_replication(spa_t *spa)
1637 {
1638         /*
1639          * As of SPA_VERSION == SPA_VERSION_DITTO_BLOCKS, we are able to
1640          * handle BPs with more than one DVA allocated.  Set our max
1641          * replication level accordingly.
1642          */
1643         if (spa_version(spa) < SPA_VERSION_DITTO_BLOCKS)
1644                 return (1);
1645         return (MIN(SPA_DVAS_PER_BP, spa_max_replication_override));
1646 }
1647 
1648 int
1649 spa_prev_software_version(spa_t *spa)
1650 {
1651         return (spa->spa_prev_software_version);
1652 }
1653 
1654 uint64_t
1655 spa_deadman_synctime(spa_t *spa)
1656 {
1657         return (spa->spa_deadman_synctime);
1658 }
1659 
1660 uint64_t
1661 dva_get_dsize_sync(spa_t *spa, const dva_t *dva)
1662 {
1663         uint64_t asize = DVA_GET_ASIZE(dva);
1664         uint64_t dsize = asize;
1665 
1666         ASSERT(spa_config_held(spa, SCL_ALL, RW_READER) != 0);
1667 
1668         if (asize != 0 && spa->spa_deflate) {
1669                 vdev_t *vd = vdev_lookup_top(spa, DVA_GET_VDEV(dva));
1670                 dsize = (asize >> SPA_MINBLOCKSHIFT) * vd->vdev_deflate_ratio;
1671         }
1672 
1673         return (dsize);
1674 }
1675 
1676 uint64_t
1677 bp_get_dsize_sync(spa_t *spa, const blkptr_t *bp)
1678 {
1679         uint64_t dsize = 0;
1680 
1681         for (int d = 0; d < BP_GET_NDVAS(bp); d++)
1682                 dsize += dva_get_dsize_sync(spa, &bp->blk_dva[d]);
1683 
1684         return (dsize);
1685 }
1686 
1687 uint64_t
1688 bp_get_dsize(spa_t *spa, const blkptr_t *bp)
1689 {
1690         uint64_t dsize = 0;
1691 
1692         spa_config_enter(spa, SCL_VDEV, FTAG, RW_READER);
1693 
1694         for (int d = 0; d < BP_GET_NDVAS(bp); d++)
1695                 dsize += dva_get_dsize_sync(spa, &bp->blk_dva[d]);
1696 
1697         spa_config_exit(spa, SCL_VDEV, FTAG);
1698 
1699         return (dsize);
1700 }
1701 
1702 /*
1703  * ==========================================================================
1704  * Initialization and Termination
1705  * ==========================================================================
1706  */
1707 
1708 static int
1709 spa_name_compare(const void *a1, const void *a2)
1710 {
1711         const spa_t *s1 = a1;
1712         const spa_t *s2 = a2;
1713         int s;
1714 
1715         s = strcmp(s1->spa_name, s2->spa_name);
1716         if (s > 0)
1717                 return (1);
1718         if (s < 0)
1719                 return (-1);
1720         return (0);
1721 }
1722 
1723 int
1724 spa_busy(void)
1725 {
1726         return (spa_active_count);
1727 }
1728 
1729 void
1730 spa_boot_init()
1731 {
1732         spa_config_load();
1733 }
1734 
1735 void
1736 spa_init(int mode)
1737 {
1738         mutex_init(&spa_namespace_lock, NULL, MUTEX_DEFAULT, NULL);
1739         mutex_init(&spa_spare_lock, NULL, MUTEX_DEFAULT, NULL);
1740         mutex_init(&spa_l2cache_lock, NULL, MUTEX_DEFAULT, NULL);
1741         cv_init(&spa_namespace_cv, NULL, CV_DEFAULT, NULL);
1742 
1743         avl_create(&spa_namespace_avl, spa_name_compare, sizeof (spa_t),
1744             offsetof(spa_t, spa_avl));
1745 
1746         avl_create(&spa_spare_avl, spa_spare_compare, sizeof (spa_aux_t),
1747             offsetof(spa_aux_t, aux_avl));
1748 
1749         avl_create(&spa_l2cache_avl, spa_l2cache_compare, sizeof (spa_aux_t),
1750             offsetof(spa_aux_t, aux_avl));
1751 
1752         spa_mode_global = mode;
1753 
1754 #ifdef _KERNEL
1755         spa_arch_init();
1756 #else
1757         if (spa_mode_global != FREAD && dprintf_find_string("watch")) {
1758                 arc_procfd = open("/proc/self/ctl", O_WRONLY);
1759                 if (arc_procfd == -1) {
1760                         perror("could not enable watchpoints: "
1761                             "opening /proc/self/ctl failed: ");
1762                 } else {
1763                         arc_watch = B_TRUE;
1764                 }
1765         }
1766 #endif
1767 
1768         refcount_init();
1769         unique_init();
1770         range_tree_init();
1771         zio_init();
1772         dmu_init();
1773         zil_init();
1774         vdev_cache_stat_init();
1775         zfs_prop_init();
1776         zpool_prop_init();
1777         zpool_feature_init();
1778         spa_config_load();
1779         l2arc_start();
1780 }
1781 
1782 void
1783 spa_fini(void)
1784 {
1785         l2arc_stop();
1786 
1787         spa_evict_all();
1788 
1789         vdev_cache_stat_fini();
1790         zil_fini();
1791         dmu_fini();
1792         zio_fini();
1793         range_tree_fini();
1794         unique_fini();
1795         refcount_fini();
1796 
1797         avl_destroy(&spa_namespace_avl);
1798         avl_destroy(&spa_spare_avl);
1799         avl_destroy(&spa_l2cache_avl);
1800 
1801         cv_destroy(&spa_namespace_cv);
1802         mutex_destroy(&spa_namespace_lock);
1803         mutex_destroy(&spa_spare_lock);
1804         mutex_destroy(&spa_l2cache_lock);
1805 }
1806 
1807 /*
1808  * Return whether this pool has slogs. No locking needed.
1809  * It's not a problem if the wrong answer is returned as it's only for
1810  * performance and not correctness
1811  */
1812 boolean_t
1813 spa_has_slogs(spa_t *spa)
1814 {
1815         return (spa->spa_log_class->mc_rotor != NULL);
1816 }
1817 
1818 spa_log_state_t
1819 spa_get_log_state(spa_t *spa)
1820 {
1821         return (spa->spa_log_state);
1822 }
1823 
1824 void
1825 spa_set_log_state(spa_t *spa, spa_log_state_t state)
1826 {
1827         spa->spa_log_state = state;
1828 }
1829 
1830 boolean_t
1831 spa_is_root(spa_t *spa)
1832 {
1833         return (spa->spa_is_root);
1834 }
1835 
1836 boolean_t
1837 spa_writeable(spa_t *spa)
1838 {
1839         return (!!(spa->spa_mode & FWRITE));
1840 }
1841 
1842 int
1843 spa_mode(spa_t *spa)
1844 {
1845         return (spa->spa_mode);
1846 }
1847 
1848 uint64_t
1849 spa_bootfs(spa_t *spa)
1850 {
1851         return (spa->spa_bootfs);
1852 }
1853 
1854 uint64_t
1855 spa_delegation(spa_t *spa)
1856 {
1857         return (spa->spa_delegation);
1858 }
1859 
1860 objset_t *
1861 spa_meta_objset(spa_t *spa)
1862 {
1863         return (spa->spa_meta_objset);
1864 }
1865 
1866 enum zio_checksum
1867 spa_dedup_checksum(spa_t *spa)
1868 {
1869         return (spa->spa_dedup_checksum);
1870 }
1871 
1872 /*
1873  * Reset pool scan stat per scan pass (or reboot).
1874  */
1875 void
1876 spa_scan_stat_init(spa_t *spa)
1877 {
1878         /* data not stored on disk */
1879         spa->spa_scan_pass_start = gethrestime_sec();
1880         spa->spa_scan_pass_exam = 0;
1881         vdev_scan_stat_init(spa->spa_root_vdev);
1882 }
1883 
1884 /*
1885  * Get scan stats for zpool status reports
1886  */
1887 int
1888 spa_scan_get_stats(spa_t *spa, pool_scan_stat_t *ps)
1889 {
1890         dsl_scan_t *scn = spa->spa_dsl_pool ? spa->spa_dsl_pool->dp_scan : NULL;
1891 
1892         if (scn == NULL || scn->scn_phys.scn_func == POOL_SCAN_NONE)
1893                 return (SET_ERROR(ENOENT));
1894         bzero(ps, sizeof (pool_scan_stat_t));
1895 
1896         /* data stored on disk */
1897         ps->pss_func = scn->scn_phys.scn_func;
1898         ps->pss_start_time = scn->scn_phys.scn_start_time;
1899         ps->pss_end_time = scn->scn_phys.scn_end_time;
1900         ps->pss_to_examine = scn->scn_phys.scn_to_examine;
1901         ps->pss_examined = scn->scn_phys.scn_examined;
1902         ps->pss_to_process = scn->scn_phys.scn_to_process;
1903         ps->pss_processed = scn->scn_phys.scn_processed;
1904         ps->pss_errors = scn->scn_phys.scn_errors;
1905         ps->pss_state = scn->scn_phys.scn_state;
1906 
1907         /* data not stored on disk */
1908         ps->pss_pass_start = spa->spa_scan_pass_start;
1909         ps->pss_pass_exam = spa->spa_scan_pass_exam;
1910 
1911         return (0);
1912 }
1913 
1914 boolean_t
1915 spa_debug_enabled(spa_t *spa)
1916 {
1917         return (spa->spa_debug);
1918 }
--- EOF ---