xref: /titanic_44/usr/src/uts/common/fs/zfs/spa.c (revision 4e5b757fbcf21077677360be274461dcd9064106)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 /*
30  * This file contains all the routines used when modifying on-disk SPA state.
31  * This includes opening, importing, destroying, exporting a pool, and syncing a
32  * pool.
33  */
34 
35 #include <sys/zfs_context.h>
36 #include <sys/fm/fs/zfs.h>
37 #include <sys/spa_impl.h>
38 #include <sys/zio.h>
39 #include <sys/zio_checksum.h>
40 #include <sys/zio_compress.h>
41 #include <sys/dmu.h>
42 #include <sys/dmu_tx.h>
43 #include <sys/zap.h>
44 #include <sys/zil.h>
45 #include <sys/vdev_impl.h>
46 #include <sys/metaslab.h>
47 #include <sys/uberblock_impl.h>
48 #include <sys/txg.h>
49 #include <sys/avl.h>
50 #include <sys/dmu_traverse.h>
51 #include <sys/dmu_objset.h>
52 #include <sys/unique.h>
53 #include <sys/dsl_pool.h>
54 #include <sys/dsl_dataset.h>
55 #include <sys/dsl_dir.h>
56 #include <sys/dsl_prop.h>
57 #include <sys/dsl_synctask.h>
58 #include <sys/fs/zfs.h>
59 #include <sys/callb.h>
60 #include <sys/systeminfo.h>
61 #include <sys/sunddi.h>
62 
63 int zio_taskq_threads = 8;
64 
65 /*
66  * ==========================================================================
67  * SPA state manipulation (open/create/destroy/import/export)
68  * ==========================================================================
69  */
70 
71 static int
72 spa_error_entry_compare(const void *a, const void *b)
73 {
74 	spa_error_entry_t *sa = (spa_error_entry_t *)a;
75 	spa_error_entry_t *sb = (spa_error_entry_t *)b;
76 	int ret;
77 
78 	ret = bcmp(&sa->se_bookmark, &sb->se_bookmark,
79 	    sizeof (zbookmark_t));
80 
81 	if (ret < 0)
82 		return (-1);
83 	else if (ret > 0)
84 		return (1);
85 	else
86 		return (0);
87 }
88 
89 /*
90  * Utility function which retrieves copies of the current logs and
91  * re-initializes them in the process.
92  */
93 void
94 spa_get_errlists(spa_t *spa, avl_tree_t *last, avl_tree_t *scrub)
95 {
96 	ASSERT(MUTEX_HELD(&spa->spa_errlist_lock));
97 
98 	bcopy(&spa->spa_errlist_last, last, sizeof (avl_tree_t));
99 	bcopy(&spa->spa_errlist_scrub, scrub, sizeof (avl_tree_t));
100 
101 	avl_create(&spa->spa_errlist_scrub,
102 	    spa_error_entry_compare, sizeof (spa_error_entry_t),
103 	    offsetof(spa_error_entry_t, se_avl));
104 	avl_create(&spa->spa_errlist_last,
105 	    spa_error_entry_compare, sizeof (spa_error_entry_t),
106 	    offsetof(spa_error_entry_t, se_avl));
107 }
108 
109 /*
110  * Activate an uninitialized pool.
111  */
112 static void
113 spa_activate(spa_t *spa)
114 {
115 	int t;
116 
117 	ASSERT(spa->spa_state == POOL_STATE_UNINITIALIZED);
118 
119 	spa->spa_state = POOL_STATE_ACTIVE;
120 
121 	spa->spa_normal_class = metaslab_class_create();
122 
123 	for (t = 0; t < ZIO_TYPES; t++) {
124 		spa->spa_zio_issue_taskq[t] = taskq_create("spa_zio_issue",
125 		    zio_taskq_threads, maxclsyspri, 50, INT_MAX,
126 		    TASKQ_PREPOPULATE);
127 		spa->spa_zio_intr_taskq[t] = taskq_create("spa_zio_intr",
128 		    zio_taskq_threads, maxclsyspri, 50, INT_MAX,
129 		    TASKQ_PREPOPULATE);
130 	}
131 
132 	rw_init(&spa->spa_traverse_lock, NULL, RW_DEFAULT, NULL);
133 
134 	mutex_init(&spa->spa_async_lock, NULL, MUTEX_DEFAULT, NULL);
135 	mutex_init(&spa->spa_config_cache_lock, NULL, MUTEX_DEFAULT, NULL);
136 	mutex_init(&spa->spa_scrub_lock, NULL, MUTEX_DEFAULT, NULL);
137 	mutex_init(&spa->spa_errlog_lock, NULL, MUTEX_DEFAULT, NULL);
138 	mutex_init(&spa->spa_errlist_lock, NULL, MUTEX_DEFAULT, NULL);
139 	mutex_init(&spa->spa_config_lock.scl_lock, NULL, MUTEX_DEFAULT, NULL);
140 	mutex_init(&spa->spa_sync_bplist.bpl_lock, NULL, MUTEX_DEFAULT, NULL);
141 	mutex_init(&spa->spa_history_lock, NULL, MUTEX_DEFAULT, NULL);
142 	mutex_init(&spa->spa_props_lock, NULL, MUTEX_DEFAULT, NULL);
143 
144 	list_create(&spa->spa_dirty_list, sizeof (vdev_t),
145 	    offsetof(vdev_t, vdev_dirty_node));
146 
147 	txg_list_create(&spa->spa_vdev_txg_list,
148 	    offsetof(struct vdev, vdev_txg_node));
149 
150 	avl_create(&spa->spa_errlist_scrub,
151 	    spa_error_entry_compare, sizeof (spa_error_entry_t),
152 	    offsetof(spa_error_entry_t, se_avl));
153 	avl_create(&spa->spa_errlist_last,
154 	    spa_error_entry_compare, sizeof (spa_error_entry_t),
155 	    offsetof(spa_error_entry_t, se_avl));
156 }
157 
158 /*
159  * Opposite of spa_activate().
160  */
161 static void
162 spa_deactivate(spa_t *spa)
163 {
164 	int t;
165 
166 	ASSERT(spa->spa_sync_on == B_FALSE);
167 	ASSERT(spa->spa_dsl_pool == NULL);
168 	ASSERT(spa->spa_root_vdev == NULL);
169 
170 	ASSERT(spa->spa_state != POOL_STATE_UNINITIALIZED);
171 
172 	txg_list_destroy(&spa->spa_vdev_txg_list);
173 
174 	list_destroy(&spa->spa_dirty_list);
175 
176 	rw_destroy(&spa->spa_traverse_lock);
177 
178 	for (t = 0; t < ZIO_TYPES; t++) {
179 		taskq_destroy(spa->spa_zio_issue_taskq[t]);
180 		taskq_destroy(spa->spa_zio_intr_taskq[t]);
181 		spa->spa_zio_issue_taskq[t] = NULL;
182 		spa->spa_zio_intr_taskq[t] = NULL;
183 	}
184 
185 	metaslab_class_destroy(spa->spa_normal_class);
186 	spa->spa_normal_class = NULL;
187 
188 	/*
189 	 * If this was part of an import or the open otherwise failed, we may
190 	 * still have errors left in the queues.  Empty them just in case.
191 	 */
192 	spa_errlog_drain(spa);
193 
194 	avl_destroy(&spa->spa_errlist_scrub);
195 	avl_destroy(&spa->spa_errlist_last);
196 
197 	spa->spa_state = POOL_STATE_UNINITIALIZED;
198 }
199 
200 /*
201  * Verify a pool configuration, and construct the vdev tree appropriately.  This
202  * will create all the necessary vdevs in the appropriate layout, with each vdev
203  * in the CLOSED state.  This will prep the pool before open/creation/import.
204  * All vdev validation is done by the vdev_alloc() routine.
205  */
206 static int
207 spa_config_parse(spa_t *spa, vdev_t **vdp, nvlist_t *nv, vdev_t *parent,
208     uint_t id, int atype)
209 {
210 	nvlist_t **child;
211 	uint_t c, children;
212 	int error;
213 
214 	if ((error = vdev_alloc(spa, vdp, nv, parent, id, atype)) != 0)
215 		return (error);
216 
217 	if ((*vdp)->vdev_ops->vdev_op_leaf)
218 		return (0);
219 
220 	if (nvlist_lookup_nvlist_array(nv, ZPOOL_CONFIG_CHILDREN,
221 	    &child, &children) != 0) {
222 		vdev_free(*vdp);
223 		*vdp = NULL;
224 		return (EINVAL);
225 	}
226 
227 	for (c = 0; c < children; c++) {
228 		vdev_t *vd;
229 		if ((error = spa_config_parse(spa, &vd, child[c], *vdp, c,
230 		    atype)) != 0) {
231 			vdev_free(*vdp);
232 			*vdp = NULL;
233 			return (error);
234 		}
235 	}
236 
237 	ASSERT(*vdp != NULL);
238 
239 	return (0);
240 }
241 
242 /*
243  * Opposite of spa_load().
244  */
245 static void
246 spa_unload(spa_t *spa)
247 {
248 	int i;
249 
250 	/*
251 	 * Stop async tasks.
252 	 */
253 	spa_async_suspend(spa);
254 
255 	/*
256 	 * Stop syncing.
257 	 */
258 	if (spa->spa_sync_on) {
259 		txg_sync_stop(spa->spa_dsl_pool);
260 		spa->spa_sync_on = B_FALSE;
261 	}
262 
263 	/*
264 	 * Wait for any outstanding prefetch I/O to complete.
265 	 */
266 	spa_config_enter(spa, RW_WRITER, FTAG);
267 	spa_config_exit(spa, FTAG);
268 
269 	/*
270 	 * Close the dsl pool.
271 	 */
272 	if (spa->spa_dsl_pool) {
273 		dsl_pool_close(spa->spa_dsl_pool);
274 		spa->spa_dsl_pool = NULL;
275 	}
276 
277 	/*
278 	 * Close all vdevs.
279 	 */
280 	if (spa->spa_root_vdev)
281 		vdev_free(spa->spa_root_vdev);
282 	ASSERT(spa->spa_root_vdev == NULL);
283 
284 	for (i = 0; i < spa->spa_nspares; i++)
285 		vdev_free(spa->spa_spares[i]);
286 	if (spa->spa_spares) {
287 		kmem_free(spa->spa_spares, spa->spa_nspares * sizeof (void *));
288 		spa->spa_spares = NULL;
289 	}
290 	if (spa->spa_sparelist) {
291 		nvlist_free(spa->spa_sparelist);
292 		spa->spa_sparelist = NULL;
293 	}
294 
295 	spa->spa_async_suspended = 0;
296 }
297 
298 /*
299  * Load (or re-load) the current list of vdevs describing the active spares for
300  * this pool.  When this is called, we have some form of basic information in
301  * 'spa_sparelist'.  We parse this into vdevs, try to open them, and then
302  * re-generate a more complete list including status information.
303  */
304 static void
305 spa_load_spares(spa_t *spa)
306 {
307 	nvlist_t **spares;
308 	uint_t nspares;
309 	int i;
310 	vdev_t *vd, *tvd;
311 
312 	/*
313 	 * First, close and free any existing spare vdevs.
314 	 */
315 	for (i = 0; i < spa->spa_nspares; i++) {
316 		vd = spa->spa_spares[i];
317 
318 		/* Undo the call to spa_activate() below */
319 		if ((tvd = spa_lookup_by_guid(spa, vd->vdev_guid)) != NULL &&
320 		    tvd->vdev_isspare)
321 			spa_spare_remove(tvd);
322 		vdev_close(vd);
323 		vdev_free(vd);
324 	}
325 
326 	if (spa->spa_spares)
327 		kmem_free(spa->spa_spares, spa->spa_nspares * sizeof (void *));
328 
329 	if (spa->spa_sparelist == NULL)
330 		nspares = 0;
331 	else
332 		VERIFY(nvlist_lookup_nvlist_array(spa->spa_sparelist,
333 		    ZPOOL_CONFIG_SPARES, &spares, &nspares) == 0);
334 
335 	spa->spa_nspares = (int)nspares;
336 	spa->spa_spares = NULL;
337 
338 	if (nspares == 0)
339 		return;
340 
341 	/*
342 	 * Construct the array of vdevs, opening them to get status in the
343 	 * process.   For each spare, there is potentially two different vdev_t
344 	 * structures associated with it: one in the list of spares (used only
345 	 * for basic validation purposes) and one in the active vdev
346 	 * configuration (if it's spared in).  During this phase we open and
347 	 * validate each vdev on the spare list.  If the vdev also exists in the
348 	 * active configuration, then we also mark this vdev as an active spare.
349 	 */
350 	spa->spa_spares = kmem_alloc(nspares * sizeof (void *), KM_SLEEP);
351 	for (i = 0; i < spa->spa_nspares; i++) {
352 		VERIFY(spa_config_parse(spa, &vd, spares[i], NULL, 0,
353 		    VDEV_ALLOC_SPARE) == 0);
354 		ASSERT(vd != NULL);
355 
356 		spa->spa_spares[i] = vd;
357 
358 		if ((tvd = spa_lookup_by_guid(spa, vd->vdev_guid)) != NULL) {
359 			if (!tvd->vdev_isspare)
360 				spa_spare_add(tvd);
361 
362 			/*
363 			 * We only mark the spare active if we were successfully
364 			 * able to load the vdev.  Otherwise, importing a pool
365 			 * with a bad active spare would result in strange
366 			 * behavior, because multiple pool would think the spare
367 			 * is actively in use.
368 			 *
369 			 * There is a vulnerability here to an equally bizarre
370 			 * circumstance, where a dead active spare is later
371 			 * brought back to life (onlined or otherwise).  Given
372 			 * the rarity of this scenario, and the extra complexity
373 			 * it adds, we ignore the possibility.
374 			 */
375 			if (!vdev_is_dead(tvd))
376 				spa_spare_activate(tvd);
377 		}
378 
379 		if (vdev_open(vd) != 0)
380 			continue;
381 
382 		vd->vdev_top = vd;
383 		(void) vdev_validate_spare(vd);
384 	}
385 
386 	/*
387 	 * Recompute the stashed list of spares, with status information
388 	 * this time.
389 	 */
390 	VERIFY(nvlist_remove(spa->spa_sparelist, ZPOOL_CONFIG_SPARES,
391 	    DATA_TYPE_NVLIST_ARRAY) == 0);
392 
393 	spares = kmem_alloc(spa->spa_nspares * sizeof (void *), KM_SLEEP);
394 	for (i = 0; i < spa->spa_nspares; i++)
395 		spares[i] = vdev_config_generate(spa, spa->spa_spares[i],
396 		    B_TRUE, B_TRUE);
397 	VERIFY(nvlist_add_nvlist_array(spa->spa_sparelist, ZPOOL_CONFIG_SPARES,
398 	    spares, spa->spa_nspares) == 0);
399 	for (i = 0; i < spa->spa_nspares; i++)
400 		nvlist_free(spares[i]);
401 	kmem_free(spares, spa->spa_nspares * sizeof (void *));
402 }
403 
404 static int
405 load_nvlist(spa_t *spa, uint64_t obj, nvlist_t **value)
406 {
407 	dmu_buf_t *db;
408 	char *packed = NULL;
409 	size_t nvsize = 0;
410 	int error;
411 	*value = NULL;
412 
413 	VERIFY(0 == dmu_bonus_hold(spa->spa_meta_objset, obj, FTAG, &db));
414 	nvsize = *(uint64_t *)db->db_data;
415 	dmu_buf_rele(db, FTAG);
416 
417 	packed = kmem_alloc(nvsize, KM_SLEEP);
418 	error = dmu_read(spa->spa_meta_objset, obj, 0, nvsize, packed);
419 	if (error == 0)
420 		error = nvlist_unpack(packed, nvsize, value, 0);
421 	kmem_free(packed, nvsize);
422 
423 	return (error);
424 }
425 
426 /*
427  * Load an existing storage pool, using the pool's builtin spa_config as a
428  * source of configuration information.
429  */
430 static int
431 spa_load(spa_t *spa, nvlist_t *config, spa_load_state_t state, int mosconfig)
432 {
433 	int error = 0;
434 	nvlist_t *nvroot = NULL;
435 	vdev_t *rvd;
436 	uberblock_t *ub = &spa->spa_uberblock;
437 	uint64_t config_cache_txg = spa->spa_config_txg;
438 	uint64_t pool_guid;
439 	uint64_t version;
440 	zio_t *zio;
441 
442 	spa->spa_load_state = state;
443 
444 	if (nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE, &nvroot) ||
445 	    nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_GUID, &pool_guid)) {
446 		error = EINVAL;
447 		goto out;
448 	}
449 
450 	/*
451 	 * Versioning wasn't explicitly added to the label until later, so if
452 	 * it's not present treat it as the initial version.
453 	 */
454 	if (nvlist_lookup_uint64(config, ZPOOL_CONFIG_VERSION, &version) != 0)
455 		version = ZFS_VERSION_INITIAL;
456 
457 	(void) nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_TXG,
458 	    &spa->spa_config_txg);
459 
460 	if ((state == SPA_LOAD_IMPORT || state == SPA_LOAD_TRYIMPORT) &&
461 	    spa_guid_exists(pool_guid, 0)) {
462 		error = EEXIST;
463 		goto out;
464 	}
465 
466 	spa->spa_load_guid = pool_guid;
467 
468 	/*
469 	 * Parse the configuration into a vdev tree.  We explicitly set the
470 	 * value that will be returned by spa_version() since parsing the
471 	 * configuration requires knowing the version number.
472 	 */
473 	spa_config_enter(spa, RW_WRITER, FTAG);
474 	spa->spa_ubsync.ub_version = version;
475 	error = spa_config_parse(spa, &rvd, nvroot, NULL, 0, VDEV_ALLOC_LOAD);
476 	spa_config_exit(spa, FTAG);
477 
478 	if (error != 0)
479 		goto out;
480 
481 	ASSERT(spa->spa_root_vdev == rvd);
482 	ASSERT(spa_guid(spa) == pool_guid);
483 
484 	/*
485 	 * Try to open all vdevs, loading each label in the process.
486 	 */
487 	error = vdev_open(rvd);
488 	if (error != 0)
489 		goto out;
490 
491 	/*
492 	 * Validate the labels for all leaf vdevs.  We need to grab the config
493 	 * lock because all label I/O is done with the ZIO_FLAG_CONFIG_HELD
494 	 * flag.
495 	 */
496 	spa_config_enter(spa, RW_READER, FTAG);
497 	error = vdev_validate(rvd);
498 	spa_config_exit(spa, FTAG);
499 
500 	if (error != 0)
501 		goto out;
502 
503 	if (rvd->vdev_state <= VDEV_STATE_CANT_OPEN) {
504 		error = ENXIO;
505 		goto out;
506 	}
507 
508 	/*
509 	 * Find the best uberblock.
510 	 */
511 	bzero(ub, sizeof (uberblock_t));
512 
513 	zio = zio_root(spa, NULL, NULL,
514 	    ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE);
515 	vdev_uberblock_load(zio, rvd, ub);
516 	error = zio_wait(zio);
517 
518 	/*
519 	 * If we weren't able to find a single valid uberblock, return failure.
520 	 */
521 	if (ub->ub_txg == 0) {
522 		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
523 		    VDEV_AUX_CORRUPT_DATA);
524 		error = ENXIO;
525 		goto out;
526 	}
527 
528 	/*
529 	 * If the pool is newer than the code, we can't open it.
530 	 */
531 	if (ub->ub_version > ZFS_VERSION) {
532 		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
533 		    VDEV_AUX_VERSION_NEWER);
534 		error = ENOTSUP;
535 		goto out;
536 	}
537 
538 	/*
539 	 * If the vdev guid sum doesn't match the uberblock, we have an
540 	 * incomplete configuration.
541 	 */
542 	if (rvd->vdev_guid_sum != ub->ub_guid_sum && mosconfig) {
543 		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
544 		    VDEV_AUX_BAD_GUID_SUM);
545 		error = ENXIO;
546 		goto out;
547 	}
548 
549 	/*
550 	 * Initialize internal SPA structures.
551 	 */
552 	spa->spa_state = POOL_STATE_ACTIVE;
553 	spa->spa_ubsync = spa->spa_uberblock;
554 	spa->spa_first_txg = spa_last_synced_txg(spa) + 1;
555 	error = dsl_pool_open(spa, spa->spa_first_txg, &spa->spa_dsl_pool);
556 	if (error) {
557 		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
558 		    VDEV_AUX_CORRUPT_DATA);
559 		goto out;
560 	}
561 	spa->spa_meta_objset = spa->spa_dsl_pool->dp_meta_objset;
562 
563 	if (zap_lookup(spa->spa_meta_objset,
564 	    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_CONFIG,
565 	    sizeof (uint64_t), 1, &spa->spa_config_object) != 0) {
566 		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
567 		    VDEV_AUX_CORRUPT_DATA);
568 		error = EIO;
569 		goto out;
570 	}
571 
572 	if (!mosconfig) {
573 		nvlist_t *newconfig;
574 		uint64_t hostid;
575 
576 		if (load_nvlist(spa, spa->spa_config_object, &newconfig) != 0) {
577 			vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
578 			    VDEV_AUX_CORRUPT_DATA);
579 			error = EIO;
580 			goto out;
581 		}
582 
583 		if (nvlist_lookup_uint64(newconfig, ZPOOL_CONFIG_HOSTID,
584 		    &hostid) == 0) {
585 			char *hostname;
586 			unsigned long myhostid = 0;
587 
588 			VERIFY(nvlist_lookup_string(newconfig,
589 			    ZPOOL_CONFIG_HOSTNAME, &hostname) == 0);
590 
591 			(void) ddi_strtoul(hw_serial, NULL, 10, &myhostid);
592 			if ((unsigned long)hostid != myhostid) {
593 				cmn_err(CE_WARN, "pool '%s' could not be "
594 				    "loaded as it was last accessed by "
595 				    "another system (host: %s hostid: 0x%lx).  "
596 				    "See: http://www.sun.com/msg/ZFS-8000-EY",
597 				    spa->spa_name, hostname,
598 				    (unsigned long)hostid);
599 				error = EBADF;
600 				goto out;
601 			}
602 		}
603 
604 		spa_config_set(spa, newconfig);
605 		spa_unload(spa);
606 		spa_deactivate(spa);
607 		spa_activate(spa);
608 
609 		return (spa_load(spa, newconfig, state, B_TRUE));
610 	}
611 
612 	if (zap_lookup(spa->spa_meta_objset,
613 	    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_SYNC_BPLIST,
614 	    sizeof (uint64_t), 1, &spa->spa_sync_bplist_obj) != 0) {
615 		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
616 		    VDEV_AUX_CORRUPT_DATA);
617 		error = EIO;
618 		goto out;
619 	}
620 
621 	/*
622 	 * Load the bit that tells us to use the new accounting function
623 	 * (raid-z deflation).  If we have an older pool, this will not
624 	 * be present.
625 	 */
626 	error = zap_lookup(spa->spa_meta_objset,
627 	    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_DEFLATE,
628 	    sizeof (uint64_t), 1, &spa->spa_deflate);
629 	if (error != 0 && error != ENOENT) {
630 		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
631 		    VDEV_AUX_CORRUPT_DATA);
632 		error = EIO;
633 		goto out;
634 	}
635 
636 	/*
637 	 * Load the persistent error log.  If we have an older pool, this will
638 	 * not be present.
639 	 */
640 	error = zap_lookup(spa->spa_meta_objset,
641 	    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_ERRLOG_LAST,
642 	    sizeof (uint64_t), 1, &spa->spa_errlog_last);
643 	if (error != 0 && error != ENOENT) {
644 		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
645 		    VDEV_AUX_CORRUPT_DATA);
646 		error = EIO;
647 		goto out;
648 	}
649 
650 	error = zap_lookup(spa->spa_meta_objset,
651 	    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_ERRLOG_SCRUB,
652 	    sizeof (uint64_t), 1, &spa->spa_errlog_scrub);
653 	if (error != 0 && error != ENOENT) {
654 		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
655 		    VDEV_AUX_CORRUPT_DATA);
656 		error = EIO;
657 		goto out;
658 	}
659 
660 	/*
661 	 * Load the history object.  If we have an older pool, this
662 	 * will not be present.
663 	 */
664 	error = zap_lookup(spa->spa_meta_objset,
665 	    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_HISTORY,
666 	    sizeof (uint64_t), 1, &spa->spa_history);
667 	if (error != 0 && error != ENOENT) {
668 		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
669 		    VDEV_AUX_CORRUPT_DATA);
670 		error = EIO;
671 		goto out;
672 	}
673 
674 	/*
675 	 * Load any hot spares for this pool.
676 	 */
677 	error = zap_lookup(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
678 	    DMU_POOL_SPARES, sizeof (uint64_t), 1, &spa->spa_spares_object);
679 	if (error != 0 && error != ENOENT) {
680 		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
681 		    VDEV_AUX_CORRUPT_DATA);
682 		error = EIO;
683 		goto out;
684 	}
685 	if (error == 0) {
686 		ASSERT(spa_version(spa) >= ZFS_VERSION_SPARES);
687 		if (load_nvlist(spa, spa->spa_spares_object,
688 		    &spa->spa_sparelist) != 0) {
689 			vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
690 			    VDEV_AUX_CORRUPT_DATA);
691 			error = EIO;
692 			goto out;
693 		}
694 
695 		spa_config_enter(spa, RW_WRITER, FTAG);
696 		spa_load_spares(spa);
697 		spa_config_exit(spa, FTAG);
698 	}
699 
700 	error = zap_lookup(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
701 	    DMU_POOL_PROPS, sizeof (uint64_t), 1, &spa->spa_pool_props_object);
702 
703 	if (error && error != ENOENT) {
704 		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
705 		    VDEV_AUX_CORRUPT_DATA);
706 		error = EIO;
707 		goto out;
708 	}
709 
710 	if (error == 0) {
711 		(void) zap_lookup(spa->spa_meta_objset,
712 		    spa->spa_pool_props_object,
713 		    zpool_prop_to_name(ZFS_PROP_BOOTFS),
714 		    sizeof (uint64_t), 1, &spa->spa_bootfs);
715 	}
716 
717 	/*
718 	 * Load the vdev state for all toplevel vdevs.
719 	 */
720 	vdev_load(rvd);
721 
722 	/*
723 	 * Propagate the leaf DTLs we just loaded all the way up the tree.
724 	 */
725 	spa_config_enter(spa, RW_WRITER, FTAG);
726 	vdev_dtl_reassess(rvd, 0, 0, B_FALSE);
727 	spa_config_exit(spa, FTAG);
728 
729 	/*
730 	 * Check the state of the root vdev.  If it can't be opened, it
731 	 * indicates one or more toplevel vdevs are faulted.
732 	 */
733 	if (rvd->vdev_state <= VDEV_STATE_CANT_OPEN) {
734 		error = ENXIO;
735 		goto out;
736 	}
737 
738 	if ((spa_mode & FWRITE) && state != SPA_LOAD_TRYIMPORT) {
739 		dmu_tx_t *tx;
740 		int need_update = B_FALSE;
741 		int c;
742 
743 		/*
744 		 * Claim log blocks that haven't been committed yet.
745 		 * This must all happen in a single txg.
746 		 */
747 		tx = dmu_tx_create_assigned(spa_get_dsl(spa),
748 		    spa_first_txg(spa));
749 		(void) dmu_objset_find(spa->spa_name,
750 		    zil_claim, tx, DS_FIND_CHILDREN);
751 		dmu_tx_commit(tx);
752 
753 		spa->spa_sync_on = B_TRUE;
754 		txg_sync_start(spa->spa_dsl_pool);
755 
756 		/*
757 		 * Wait for all claims to sync.
758 		 */
759 		txg_wait_synced(spa->spa_dsl_pool, 0);
760 
761 		/*
762 		 * If the config cache is stale, or we have uninitialized
763 		 * metaslabs (see spa_vdev_add()), then update the config.
764 		 */
765 		if (config_cache_txg != spa->spa_config_txg ||
766 		    state == SPA_LOAD_IMPORT)
767 			need_update = B_TRUE;
768 
769 		for (c = 0; c < rvd->vdev_children; c++)
770 			if (rvd->vdev_child[c]->vdev_ms_array == 0)
771 				need_update = B_TRUE;
772 
773 		/*
774 		 * Update the config cache asychronously in case we're the
775 		 * root pool, in which case the config cache isn't writable yet.
776 		 */
777 		if (need_update)
778 			spa_async_request(spa, SPA_ASYNC_CONFIG_UPDATE);
779 	}
780 
781 	error = 0;
782 out:
783 	if (error && error != EBADF)
784 		zfs_ereport_post(FM_EREPORT_ZFS_POOL, spa, NULL, NULL, 0, 0);
785 	spa->spa_load_state = SPA_LOAD_NONE;
786 	spa->spa_ena = 0;
787 
788 	return (error);
789 }
790 
791 /*
792  * Pool Open/Import
793  *
794  * The import case is identical to an open except that the configuration is sent
795  * down from userland, instead of grabbed from the configuration cache.  For the
796  * case of an open, the pool configuration will exist in the
797  * POOL_STATE_UNITIALIZED state.
798  *
799  * The stats information (gen/count/ustats) is used to gather vdev statistics at
800  * the same time open the pool, without having to keep around the spa_t in some
801  * ambiguous state.
802  */
803 static int
804 spa_open_common(const char *pool, spa_t **spapp, void *tag, nvlist_t **config)
805 {
806 	spa_t *spa;
807 	int error;
808 	int loaded = B_FALSE;
809 	int locked = B_FALSE;
810 
811 	*spapp = NULL;
812 
813 	/*
814 	 * As disgusting as this is, we need to support recursive calls to this
815 	 * function because dsl_dir_open() is called during spa_load(), and ends
816 	 * up calling spa_open() again.  The real fix is to figure out how to
817 	 * avoid dsl_dir_open() calling this in the first place.
818 	 */
819 	if (mutex_owner(&spa_namespace_lock) != curthread) {
820 		mutex_enter(&spa_namespace_lock);
821 		locked = B_TRUE;
822 	}
823 
824 	if ((spa = spa_lookup(pool)) == NULL) {
825 		if (locked)
826 			mutex_exit(&spa_namespace_lock);
827 		return (ENOENT);
828 	}
829 	if (spa->spa_state == POOL_STATE_UNINITIALIZED) {
830 
831 		spa_activate(spa);
832 
833 		error = spa_load(spa, spa->spa_config, SPA_LOAD_OPEN, B_FALSE);
834 
835 		if (error == EBADF) {
836 			/*
837 			 * If vdev_validate() returns failure (indicated by
838 			 * EBADF), it indicates that one of the vdevs indicates
839 			 * that the pool has been exported or destroyed.  If
840 			 * this is the case, the config cache is out of sync and
841 			 * we should remove the pool from the namespace.
842 			 */
843 			zfs_post_ok(spa, NULL);
844 			spa_unload(spa);
845 			spa_deactivate(spa);
846 			spa_remove(spa);
847 			spa_config_sync();
848 			if (locked)
849 				mutex_exit(&spa_namespace_lock);
850 			return (ENOENT);
851 		}
852 
853 		if (error) {
854 			/*
855 			 * We can't open the pool, but we still have useful
856 			 * information: the state of each vdev after the
857 			 * attempted vdev_open().  Return this to the user.
858 			 */
859 			if (config != NULL && spa->spa_root_vdev != NULL) {
860 				spa_config_enter(spa, RW_READER, FTAG);
861 				*config = spa_config_generate(spa, NULL, -1ULL,
862 				    B_TRUE);
863 				spa_config_exit(spa, FTAG);
864 			}
865 			spa_unload(spa);
866 			spa_deactivate(spa);
867 			spa->spa_last_open_failed = B_TRUE;
868 			if (locked)
869 				mutex_exit(&spa_namespace_lock);
870 			*spapp = NULL;
871 			return (error);
872 		} else {
873 			zfs_post_ok(spa, NULL);
874 			spa->spa_last_open_failed = B_FALSE;
875 		}
876 
877 		loaded = B_TRUE;
878 	}
879 
880 	spa_open_ref(spa, tag);
881 	if (locked)
882 		mutex_exit(&spa_namespace_lock);
883 
884 	*spapp = spa;
885 
886 	if (config != NULL) {
887 		spa_config_enter(spa, RW_READER, FTAG);
888 		*config = spa_config_generate(spa, NULL, -1ULL, B_TRUE);
889 		spa_config_exit(spa, FTAG);
890 	}
891 
892 	/*
893 	 * If we just loaded the pool, resilver anything that's out of date.
894 	 */
895 	if (loaded && (spa_mode & FWRITE))
896 		VERIFY(spa_scrub(spa, POOL_SCRUB_RESILVER, B_TRUE) == 0);
897 
898 	return (0);
899 }
900 
901 int
902 spa_open(const char *name, spa_t **spapp, void *tag)
903 {
904 	return (spa_open_common(name, spapp, tag, NULL));
905 }
906 
907 /*
908  * Lookup the given spa_t, incrementing the inject count in the process,
909  * preventing it from being exported or destroyed.
910  */
911 spa_t *
912 spa_inject_addref(char *name)
913 {
914 	spa_t *spa;
915 
916 	mutex_enter(&spa_namespace_lock);
917 	if ((spa = spa_lookup(name)) == NULL) {
918 		mutex_exit(&spa_namespace_lock);
919 		return (NULL);
920 	}
921 	spa->spa_inject_ref++;
922 	mutex_exit(&spa_namespace_lock);
923 
924 	return (spa);
925 }
926 
927 void
928 spa_inject_delref(spa_t *spa)
929 {
930 	mutex_enter(&spa_namespace_lock);
931 	spa->spa_inject_ref--;
932 	mutex_exit(&spa_namespace_lock);
933 }
934 
935 static void
936 spa_add_spares(spa_t *spa, nvlist_t *config)
937 {
938 	nvlist_t **spares;
939 	uint_t i, nspares;
940 	nvlist_t *nvroot;
941 	uint64_t guid;
942 	vdev_stat_t *vs;
943 	uint_t vsc;
944 	uint64_t pool;
945 
946 	if (spa->spa_nspares == 0)
947 		return;
948 
949 	VERIFY(nvlist_lookup_nvlist(config,
950 	    ZPOOL_CONFIG_VDEV_TREE, &nvroot) == 0);
951 	VERIFY(nvlist_lookup_nvlist_array(spa->spa_sparelist,
952 	    ZPOOL_CONFIG_SPARES, &spares, &nspares) == 0);
953 	if (nspares != 0) {
954 		VERIFY(nvlist_add_nvlist_array(nvroot,
955 		    ZPOOL_CONFIG_SPARES, spares, nspares) == 0);
956 		VERIFY(nvlist_lookup_nvlist_array(nvroot,
957 		    ZPOOL_CONFIG_SPARES, &spares, &nspares) == 0);
958 
959 		/*
960 		 * Go through and find any spares which have since been
961 		 * repurposed as an active spare.  If this is the case, update
962 		 * their status appropriately.
963 		 */
964 		for (i = 0; i < nspares; i++) {
965 			VERIFY(nvlist_lookup_uint64(spares[i],
966 			    ZPOOL_CONFIG_GUID, &guid) == 0);
967 			if (spa_spare_exists(guid, &pool) && pool != 0ULL) {
968 				VERIFY(nvlist_lookup_uint64_array(
969 				    spares[i], ZPOOL_CONFIG_STATS,
970 				    (uint64_t **)&vs, &vsc) == 0);
971 				vs->vs_state = VDEV_STATE_CANT_OPEN;
972 				vs->vs_aux = VDEV_AUX_SPARED;
973 			}
974 		}
975 	}
976 }
977 
978 int
979 spa_get_stats(const char *name, nvlist_t **config, char *altroot, size_t buflen)
980 {
981 	int error;
982 	spa_t *spa;
983 
984 	*config = NULL;
985 	error = spa_open_common(name, &spa, FTAG, config);
986 
987 	if (spa && *config != NULL) {
988 		VERIFY(nvlist_add_uint64(*config, ZPOOL_CONFIG_ERRCOUNT,
989 		    spa_get_errlog_size(spa)) == 0);
990 
991 		spa_add_spares(spa, *config);
992 	}
993 
994 	/*
995 	 * We want to get the alternate root even for faulted pools, so we cheat
996 	 * and call spa_lookup() directly.
997 	 */
998 	if (altroot) {
999 		if (spa == NULL) {
1000 			mutex_enter(&spa_namespace_lock);
1001 			spa = spa_lookup(name);
1002 			if (spa)
1003 				spa_altroot(spa, altroot, buflen);
1004 			else
1005 				altroot[0] = '\0';
1006 			spa = NULL;
1007 			mutex_exit(&spa_namespace_lock);
1008 		} else {
1009 			spa_altroot(spa, altroot, buflen);
1010 		}
1011 	}
1012 
1013 	if (spa != NULL)
1014 		spa_close(spa, FTAG);
1015 
1016 	return (error);
1017 }
1018 
1019 /*
1020  * Validate that the 'spares' array is well formed.  We must have an array of
1021  * nvlists, each which describes a valid leaf vdev.  If this is an import (mode
1022  * is VDEV_ALLOC_SPARE), then we allow corrupted spares to be specified, as long
1023  * as they are well-formed.
1024  */
1025 static int
1026 spa_validate_spares(spa_t *spa, nvlist_t *nvroot, uint64_t crtxg, int mode)
1027 {
1028 	nvlist_t **spares;
1029 	uint_t i, nspares;
1030 	vdev_t *vd;
1031 	int error;
1032 
1033 	/*
1034 	 * It's acceptable to have no spares specified.
1035 	 */
1036 	if (nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_SPARES,
1037 	    &spares, &nspares) != 0)
1038 		return (0);
1039 
1040 	if (nspares == 0)
1041 		return (EINVAL);
1042 
1043 	/*
1044 	 * Make sure the pool is formatted with a version that supports hot
1045 	 * spares.
1046 	 */
1047 	if (spa_version(spa) < ZFS_VERSION_SPARES)
1048 		return (ENOTSUP);
1049 
1050 	/*
1051 	 * Set the pending spare list so we correctly handle device in-use
1052 	 * checking.
1053 	 */
1054 	spa->spa_pending_spares = spares;
1055 	spa->spa_pending_nspares = nspares;
1056 
1057 	for (i = 0; i < nspares; i++) {
1058 		if ((error = spa_config_parse(spa, &vd, spares[i], NULL, 0,
1059 		    mode)) != 0)
1060 			goto out;
1061 
1062 		if (!vd->vdev_ops->vdev_op_leaf) {
1063 			vdev_free(vd);
1064 			error = EINVAL;
1065 			goto out;
1066 		}
1067 
1068 		vd->vdev_top = vd;
1069 
1070 		if ((error = vdev_open(vd)) == 0 &&
1071 		    (error = vdev_label_init(vd, crtxg,
1072 		    VDEV_LABEL_SPARE)) == 0) {
1073 			VERIFY(nvlist_add_uint64(spares[i], ZPOOL_CONFIG_GUID,
1074 			    vd->vdev_guid) == 0);
1075 		}
1076 
1077 		vdev_free(vd);
1078 
1079 		if (error && mode != VDEV_ALLOC_SPARE)
1080 			goto out;
1081 		else
1082 			error = 0;
1083 	}
1084 
1085 out:
1086 	spa->spa_pending_spares = NULL;
1087 	spa->spa_pending_nspares = 0;
1088 	return (error);
1089 }
1090 
1091 /*
1092  * Pool Creation
1093  */
1094 int
1095 spa_create(const char *pool, nvlist_t *nvroot, const char *altroot)
1096 {
1097 	spa_t *spa;
1098 	vdev_t *rvd;
1099 	dsl_pool_t *dp;
1100 	dmu_tx_t *tx;
1101 	int c, error = 0;
1102 	uint64_t txg = TXG_INITIAL;
1103 	nvlist_t **spares;
1104 	uint_t nspares;
1105 
1106 	/*
1107 	 * If this pool already exists, return failure.
1108 	 */
1109 	mutex_enter(&spa_namespace_lock);
1110 	if (spa_lookup(pool) != NULL) {
1111 		mutex_exit(&spa_namespace_lock);
1112 		return (EEXIST);
1113 	}
1114 
1115 	/*
1116 	 * Allocate a new spa_t structure.
1117 	 */
1118 	spa = spa_add(pool, altroot);
1119 	spa_activate(spa);
1120 
1121 	spa->spa_uberblock.ub_txg = txg - 1;
1122 	spa->spa_uberblock.ub_version = ZFS_VERSION;
1123 	spa->spa_ubsync = spa->spa_uberblock;
1124 
1125 	/*
1126 	 * Create the root vdev.
1127 	 */
1128 	spa_config_enter(spa, RW_WRITER, FTAG);
1129 
1130 	error = spa_config_parse(spa, &rvd, nvroot, NULL, 0, VDEV_ALLOC_ADD);
1131 
1132 	ASSERT(error != 0 || rvd != NULL);
1133 	ASSERT(error != 0 || spa->spa_root_vdev == rvd);
1134 
1135 	if (error == 0 && rvd->vdev_children == 0)
1136 		error = EINVAL;
1137 
1138 	if (error == 0 &&
1139 	    (error = vdev_create(rvd, txg, B_FALSE)) == 0 &&
1140 	    (error = spa_validate_spares(spa, nvroot, txg,
1141 	    VDEV_ALLOC_ADD)) == 0) {
1142 		for (c = 0; c < rvd->vdev_children; c++)
1143 			vdev_init(rvd->vdev_child[c], txg);
1144 		vdev_config_dirty(rvd);
1145 	}
1146 
1147 	spa_config_exit(spa, FTAG);
1148 
1149 	if (error != 0) {
1150 		spa_unload(spa);
1151 		spa_deactivate(spa);
1152 		spa_remove(spa);
1153 		mutex_exit(&spa_namespace_lock);
1154 		return (error);
1155 	}
1156 
1157 	/*
1158 	 * Get the list of spares, if specified.
1159 	 */
1160 	if (nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_SPARES,
1161 	    &spares, &nspares) == 0) {
1162 		VERIFY(nvlist_alloc(&spa->spa_sparelist, NV_UNIQUE_NAME,
1163 		    KM_SLEEP) == 0);
1164 		VERIFY(nvlist_add_nvlist_array(spa->spa_sparelist,
1165 		    ZPOOL_CONFIG_SPARES, spares, nspares) == 0);
1166 		spa_config_enter(spa, RW_WRITER, FTAG);
1167 		spa_load_spares(spa);
1168 		spa_config_exit(spa, FTAG);
1169 		spa->spa_sync_spares = B_TRUE;
1170 	}
1171 
1172 	spa->spa_dsl_pool = dp = dsl_pool_create(spa, txg);
1173 	spa->spa_meta_objset = dp->dp_meta_objset;
1174 
1175 	tx = dmu_tx_create_assigned(dp, txg);
1176 
1177 	/*
1178 	 * Create the pool config object.
1179 	 */
1180 	spa->spa_config_object = dmu_object_alloc(spa->spa_meta_objset,
1181 	    DMU_OT_PACKED_NVLIST, 1 << 14,
1182 	    DMU_OT_PACKED_NVLIST_SIZE, sizeof (uint64_t), tx);
1183 
1184 	if (zap_add(spa->spa_meta_objset,
1185 	    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_CONFIG,
1186 	    sizeof (uint64_t), 1, &spa->spa_config_object, tx) != 0) {
1187 		cmn_err(CE_PANIC, "failed to add pool config");
1188 	}
1189 
1190 	/* Newly created pools are always deflated. */
1191 	spa->spa_deflate = TRUE;
1192 	if (zap_add(spa->spa_meta_objset,
1193 	    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_DEFLATE,
1194 	    sizeof (uint64_t), 1, &spa->spa_deflate, tx) != 0) {
1195 		cmn_err(CE_PANIC, "failed to add deflate");
1196 	}
1197 
1198 	/*
1199 	 * Create the deferred-free bplist object.  Turn off compression
1200 	 * because sync-to-convergence takes longer if the blocksize
1201 	 * keeps changing.
1202 	 */
1203 	spa->spa_sync_bplist_obj = bplist_create(spa->spa_meta_objset,
1204 	    1 << 14, tx);
1205 	dmu_object_set_compress(spa->spa_meta_objset, spa->spa_sync_bplist_obj,
1206 	    ZIO_COMPRESS_OFF, tx);
1207 
1208 	if (zap_add(spa->spa_meta_objset,
1209 	    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_SYNC_BPLIST,
1210 	    sizeof (uint64_t), 1, &spa->spa_sync_bplist_obj, tx) != 0) {
1211 		cmn_err(CE_PANIC, "failed to add bplist");
1212 	}
1213 
1214 	/*
1215 	 * Create the pool's history object.
1216 	 */
1217 	spa_history_create_obj(spa, tx);
1218 
1219 	dmu_tx_commit(tx);
1220 
1221 	spa->spa_bootfs = zfs_prop_default_numeric(ZFS_PROP_BOOTFS);
1222 	spa->spa_sync_on = B_TRUE;
1223 	txg_sync_start(spa->spa_dsl_pool);
1224 
1225 	/*
1226 	 * We explicitly wait for the first transaction to complete so that our
1227 	 * bean counters are appropriately updated.
1228 	 */
1229 	txg_wait_synced(spa->spa_dsl_pool, txg);
1230 
1231 	spa_config_sync();
1232 
1233 	mutex_exit(&spa_namespace_lock);
1234 
1235 	return (0);
1236 }
1237 
1238 /*
1239  * Import the given pool into the system.  We set up the necessary spa_t and
1240  * then call spa_load() to do the dirty work.
1241  */
1242 int
1243 spa_import(const char *pool, nvlist_t *config, const char *altroot)
1244 {
1245 	spa_t *spa;
1246 	int error;
1247 	nvlist_t *nvroot;
1248 	nvlist_t **spares;
1249 	uint_t nspares;
1250 
1251 	if (!(spa_mode & FWRITE))
1252 		return (EROFS);
1253 
1254 	/*
1255 	 * If a pool with this name exists, return failure.
1256 	 */
1257 	mutex_enter(&spa_namespace_lock);
1258 	if (spa_lookup(pool) != NULL) {
1259 		mutex_exit(&spa_namespace_lock);
1260 		return (EEXIST);
1261 	}
1262 
1263 	/*
1264 	 * Create and initialize the spa structure.
1265 	 */
1266 	spa = spa_add(pool, altroot);
1267 	spa_activate(spa);
1268 
1269 	/*
1270 	 * Pass off the heavy lifting to spa_load().
1271 	 * Pass TRUE for mosconfig because the user-supplied config
1272 	 * is actually the one to trust when doing an import.
1273 	 */
1274 	error = spa_load(spa, config, SPA_LOAD_IMPORT, B_TRUE);
1275 
1276 	spa_config_enter(spa, RW_WRITER, FTAG);
1277 	/*
1278 	 * Toss any existing sparelist, as it doesn't have any validity anymore,
1279 	 * and conflicts with spa_has_spare().
1280 	 */
1281 	if (spa->spa_sparelist) {
1282 		nvlist_free(spa->spa_sparelist);
1283 		spa->spa_sparelist = NULL;
1284 		spa_load_spares(spa);
1285 	}
1286 
1287 	VERIFY(nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE,
1288 	    &nvroot) == 0);
1289 	if (error == 0)
1290 		error = spa_validate_spares(spa, nvroot, -1ULL,
1291 		    VDEV_ALLOC_SPARE);
1292 	spa_config_exit(spa, FTAG);
1293 
1294 	if (error != 0) {
1295 		spa_unload(spa);
1296 		spa_deactivate(spa);
1297 		spa_remove(spa);
1298 		mutex_exit(&spa_namespace_lock);
1299 		return (error);
1300 	}
1301 
1302 	/*
1303 	 * Override any spares as specified by the user, as these may have
1304 	 * correct device names/devids, etc.
1305 	 */
1306 	if (nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_SPARES,
1307 	    &spares, &nspares) == 0) {
1308 		if (spa->spa_sparelist)
1309 			VERIFY(nvlist_remove(spa->spa_sparelist,
1310 			    ZPOOL_CONFIG_SPARES, DATA_TYPE_NVLIST_ARRAY) == 0);
1311 		else
1312 			VERIFY(nvlist_alloc(&spa->spa_sparelist,
1313 			    NV_UNIQUE_NAME, KM_SLEEP) == 0);
1314 		VERIFY(nvlist_add_nvlist_array(spa->spa_sparelist,
1315 		    ZPOOL_CONFIG_SPARES, spares, nspares) == 0);
1316 		spa_config_enter(spa, RW_WRITER, FTAG);
1317 		spa_load_spares(spa);
1318 		spa_config_exit(spa, FTAG);
1319 		spa->spa_sync_spares = B_TRUE;
1320 	}
1321 
1322 	/*
1323 	 * Update the config cache to include the newly-imported pool.
1324 	 */
1325 	spa_config_update(spa, SPA_CONFIG_UPDATE_POOL);
1326 
1327 	mutex_exit(&spa_namespace_lock);
1328 
1329 	/*
1330 	 * Resilver anything that's out of date.
1331 	 */
1332 	if (spa_mode & FWRITE)
1333 		VERIFY(spa_scrub(spa, POOL_SCRUB_RESILVER, B_TRUE) == 0);
1334 
1335 	return (0);
1336 }
1337 
1338 /*
1339  * This (illegal) pool name is used when temporarily importing a spa_t in order
1340  * to get the vdev stats associated with the imported devices.
1341  */
1342 #define	TRYIMPORT_NAME	"$import"
1343 
1344 nvlist_t *
1345 spa_tryimport(nvlist_t *tryconfig)
1346 {
1347 	nvlist_t *config = NULL;
1348 	char *poolname;
1349 	spa_t *spa;
1350 	uint64_t state;
1351 
1352 	if (nvlist_lookup_string(tryconfig, ZPOOL_CONFIG_POOL_NAME, &poolname))
1353 		return (NULL);
1354 
1355 	if (nvlist_lookup_uint64(tryconfig, ZPOOL_CONFIG_POOL_STATE, &state))
1356 		return (NULL);
1357 
1358 	/*
1359 	 * Create and initialize the spa structure.
1360 	 */
1361 	mutex_enter(&spa_namespace_lock);
1362 	spa = spa_add(TRYIMPORT_NAME, NULL);
1363 	spa_activate(spa);
1364 
1365 	/*
1366 	 * Pass off the heavy lifting to spa_load().
1367 	 * Pass TRUE for mosconfig because the user-supplied config
1368 	 * is actually the one to trust when doing an import.
1369 	 */
1370 	(void) spa_load(spa, tryconfig, SPA_LOAD_TRYIMPORT, B_TRUE);
1371 
1372 	/*
1373 	 * If 'tryconfig' was at least parsable, return the current config.
1374 	 */
1375 	if (spa->spa_root_vdev != NULL) {
1376 		spa_config_enter(spa, RW_READER, FTAG);
1377 		config = spa_config_generate(spa, NULL, -1ULL, B_TRUE);
1378 		spa_config_exit(spa, FTAG);
1379 		VERIFY(nvlist_add_string(config, ZPOOL_CONFIG_POOL_NAME,
1380 		    poolname) == 0);
1381 		VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_POOL_STATE,
1382 		    state) == 0);
1383 		VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_TIMESTAMP,
1384 		    spa->spa_uberblock.ub_timestamp) == 0);
1385 
1386 		/*
1387 		 * Add the list of hot spares.
1388 		 */
1389 		spa_add_spares(spa, config);
1390 	}
1391 
1392 	spa_unload(spa);
1393 	spa_deactivate(spa);
1394 	spa_remove(spa);
1395 	mutex_exit(&spa_namespace_lock);
1396 
1397 	return (config);
1398 }
1399 
1400 /*
1401  * Pool export/destroy
1402  *
1403  * The act of destroying or exporting a pool is very simple.  We make sure there
1404  * is no more pending I/O and any references to the pool are gone.  Then, we
1405  * update the pool state and sync all the labels to disk, removing the
1406  * configuration from the cache afterwards.
1407  */
1408 static int
1409 spa_export_common(char *pool, int new_state, nvlist_t **oldconfig)
1410 {
1411 	spa_t *spa;
1412 
1413 	if (oldconfig)
1414 		*oldconfig = NULL;
1415 
1416 	if (!(spa_mode & FWRITE))
1417 		return (EROFS);
1418 
1419 	mutex_enter(&spa_namespace_lock);
1420 	if ((spa = spa_lookup(pool)) == NULL) {
1421 		mutex_exit(&spa_namespace_lock);
1422 		return (ENOENT);
1423 	}
1424 
1425 	/*
1426 	 * Put a hold on the pool, drop the namespace lock, stop async tasks,
1427 	 * reacquire the namespace lock, and see if we can export.
1428 	 */
1429 	spa_open_ref(spa, FTAG);
1430 	mutex_exit(&spa_namespace_lock);
1431 	spa_async_suspend(spa);
1432 	mutex_enter(&spa_namespace_lock);
1433 	spa_close(spa, FTAG);
1434 
1435 	/*
1436 	 * The pool will be in core if it's openable,
1437 	 * in which case we can modify its state.
1438 	 */
1439 	if (spa->spa_state != POOL_STATE_UNINITIALIZED && spa->spa_sync_on) {
1440 		/*
1441 		 * Objsets may be open only because they're dirty, so we
1442 		 * have to force it to sync before checking spa_refcnt.
1443 		 */
1444 		spa_scrub_suspend(spa);
1445 		txg_wait_synced(spa->spa_dsl_pool, 0);
1446 
1447 		/*
1448 		 * A pool cannot be exported or destroyed if there are active
1449 		 * references.  If we are resetting a pool, allow references by
1450 		 * fault injection handlers.
1451 		 */
1452 		if (!spa_refcount_zero(spa) ||
1453 		    (spa->spa_inject_ref != 0 &&
1454 		    new_state != POOL_STATE_UNINITIALIZED)) {
1455 			spa_scrub_resume(spa);
1456 			spa_async_resume(spa);
1457 			mutex_exit(&spa_namespace_lock);
1458 			return (EBUSY);
1459 		}
1460 
1461 		spa_scrub_resume(spa);
1462 		VERIFY(spa_scrub(spa, POOL_SCRUB_NONE, B_TRUE) == 0);
1463 
1464 		/*
1465 		 * We want this to be reflected on every label,
1466 		 * so mark them all dirty.  spa_unload() will do the
1467 		 * final sync that pushes these changes out.
1468 		 */
1469 		if (new_state != POOL_STATE_UNINITIALIZED) {
1470 			spa_config_enter(spa, RW_WRITER, FTAG);
1471 			spa->spa_state = new_state;
1472 			spa->spa_final_txg = spa_last_synced_txg(spa) + 1;
1473 			vdev_config_dirty(spa->spa_root_vdev);
1474 			spa_config_exit(spa, FTAG);
1475 		}
1476 	}
1477 
1478 	if (spa->spa_state != POOL_STATE_UNINITIALIZED) {
1479 		spa_unload(spa);
1480 		spa_deactivate(spa);
1481 	}
1482 
1483 	if (oldconfig && spa->spa_config)
1484 		VERIFY(nvlist_dup(spa->spa_config, oldconfig, 0) == 0);
1485 
1486 	if (new_state != POOL_STATE_UNINITIALIZED) {
1487 		spa_remove(spa);
1488 		spa_config_sync();
1489 	}
1490 	mutex_exit(&spa_namespace_lock);
1491 
1492 	return (0);
1493 }
1494 
1495 /*
1496  * Destroy a storage pool.
1497  */
1498 int
1499 spa_destroy(char *pool)
1500 {
1501 	return (spa_export_common(pool, POOL_STATE_DESTROYED, NULL));
1502 }
1503 
1504 /*
1505  * Export a storage pool.
1506  */
1507 int
1508 spa_export(char *pool, nvlist_t **oldconfig)
1509 {
1510 	return (spa_export_common(pool, POOL_STATE_EXPORTED, oldconfig));
1511 }
1512 
1513 /*
1514  * Similar to spa_export(), this unloads the spa_t without actually removing it
1515  * from the namespace in any way.
1516  */
1517 int
1518 spa_reset(char *pool)
1519 {
1520 	return (spa_export_common(pool, POOL_STATE_UNINITIALIZED, NULL));
1521 }
1522 
1523 
1524 /*
1525  * ==========================================================================
1526  * Device manipulation
1527  * ==========================================================================
1528  */
1529 
1530 /*
1531  * Add capacity to a storage pool.
1532  */
1533 int
1534 spa_vdev_add(spa_t *spa, nvlist_t *nvroot)
1535 {
1536 	uint64_t txg;
1537 	int c, error;
1538 	vdev_t *rvd = spa->spa_root_vdev;
1539 	vdev_t *vd, *tvd;
1540 	nvlist_t **spares;
1541 	uint_t i, nspares;
1542 
1543 	txg = spa_vdev_enter(spa);
1544 
1545 	if ((error = spa_config_parse(spa, &vd, nvroot, NULL, 0,
1546 	    VDEV_ALLOC_ADD)) != 0)
1547 		return (spa_vdev_exit(spa, NULL, txg, error));
1548 
1549 	spa->spa_pending_vdev = vd;
1550 
1551 	if (nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_SPARES,
1552 	    &spares, &nspares) != 0)
1553 		nspares = 0;
1554 
1555 	if (vd->vdev_children == 0 && nspares == 0) {
1556 		spa->spa_pending_vdev = NULL;
1557 		return (spa_vdev_exit(spa, vd, txg, EINVAL));
1558 	}
1559 
1560 	if (vd->vdev_children != 0) {
1561 		if ((error = vdev_create(vd, txg, B_FALSE)) != 0) {
1562 			spa->spa_pending_vdev = NULL;
1563 			return (spa_vdev_exit(spa, vd, txg, error));
1564 		}
1565 	}
1566 
1567 	/*
1568 	 * We must validate the spares after checking the children.  Otherwise,
1569 	 * vdev_inuse() will blindly overwrite the spare.
1570 	 */
1571 	if ((error = spa_validate_spares(spa, nvroot, txg,
1572 	    VDEV_ALLOC_ADD)) != 0) {
1573 		spa->spa_pending_vdev = NULL;
1574 		return (spa_vdev_exit(spa, vd, txg, error));
1575 	}
1576 
1577 	spa->spa_pending_vdev = NULL;
1578 
1579 	/*
1580 	 * Transfer each new top-level vdev from vd to rvd.
1581 	 */
1582 	for (c = 0; c < vd->vdev_children; c++) {
1583 		tvd = vd->vdev_child[c];
1584 		vdev_remove_child(vd, tvd);
1585 		tvd->vdev_id = rvd->vdev_children;
1586 		vdev_add_child(rvd, tvd);
1587 		vdev_config_dirty(tvd);
1588 	}
1589 
1590 	if (nspares != 0) {
1591 		if (spa->spa_sparelist != NULL) {
1592 			nvlist_t **oldspares;
1593 			uint_t oldnspares;
1594 			nvlist_t **newspares;
1595 
1596 			VERIFY(nvlist_lookup_nvlist_array(spa->spa_sparelist,
1597 			    ZPOOL_CONFIG_SPARES, &oldspares, &oldnspares) == 0);
1598 
1599 			newspares = kmem_alloc(sizeof (void *) *
1600 			    (nspares + oldnspares), KM_SLEEP);
1601 			for (i = 0; i < oldnspares; i++)
1602 				VERIFY(nvlist_dup(oldspares[i],
1603 				    &newspares[i], KM_SLEEP) == 0);
1604 			for (i = 0; i < nspares; i++)
1605 				VERIFY(nvlist_dup(spares[i],
1606 				    &newspares[i + oldnspares],
1607 				    KM_SLEEP) == 0);
1608 
1609 			VERIFY(nvlist_remove(spa->spa_sparelist,
1610 			    ZPOOL_CONFIG_SPARES, DATA_TYPE_NVLIST_ARRAY) == 0);
1611 
1612 			VERIFY(nvlist_add_nvlist_array(spa->spa_sparelist,
1613 			    ZPOOL_CONFIG_SPARES, newspares,
1614 			    nspares + oldnspares) == 0);
1615 			for (i = 0; i < oldnspares + nspares; i++)
1616 				nvlist_free(newspares[i]);
1617 			kmem_free(newspares, (oldnspares + nspares) *
1618 			    sizeof (void *));
1619 		} else {
1620 			VERIFY(nvlist_alloc(&spa->spa_sparelist,
1621 			    NV_UNIQUE_NAME, KM_SLEEP) == 0);
1622 			VERIFY(nvlist_add_nvlist_array(spa->spa_sparelist,
1623 			    ZPOOL_CONFIG_SPARES, spares, nspares) == 0);
1624 		}
1625 
1626 		spa_load_spares(spa);
1627 		spa->spa_sync_spares = B_TRUE;
1628 	}
1629 
1630 	/*
1631 	 * We have to be careful when adding new vdevs to an existing pool.
1632 	 * If other threads start allocating from these vdevs before we
1633 	 * sync the config cache, and we lose power, then upon reboot we may
1634 	 * fail to open the pool because there are DVAs that the config cache
1635 	 * can't translate.  Therefore, we first add the vdevs without
1636 	 * initializing metaslabs; sync the config cache (via spa_vdev_exit());
1637 	 * and then let spa_config_update() initialize the new metaslabs.
1638 	 *
1639 	 * spa_load() checks for added-but-not-initialized vdevs, so that
1640 	 * if we lose power at any point in this sequence, the remaining
1641 	 * steps will be completed the next time we load the pool.
1642 	 */
1643 	(void) spa_vdev_exit(spa, vd, txg, 0);
1644 
1645 	mutex_enter(&spa_namespace_lock);
1646 	spa_config_update(spa, SPA_CONFIG_UPDATE_POOL);
1647 	mutex_exit(&spa_namespace_lock);
1648 
1649 	return (0);
1650 }
1651 
1652 /*
1653  * Attach a device to a mirror.  The arguments are the path to any device
1654  * in the mirror, and the nvroot for the new device.  If the path specifies
1655  * a device that is not mirrored, we automatically insert the mirror vdev.
1656  *
1657  * If 'replacing' is specified, the new device is intended to replace the
1658  * existing device; in this case the two devices are made into their own
1659  * mirror using the 'replacing' vdev, which is functionally idendical to
1660  * the mirror vdev (it actually reuses all the same ops) but has a few
1661  * extra rules: you can't attach to it after it's been created, and upon
1662  * completion of resilvering, the first disk (the one being replaced)
1663  * is automatically detached.
1664  */
1665 int
1666 spa_vdev_attach(spa_t *spa, uint64_t guid, nvlist_t *nvroot, int replacing)
1667 {
1668 	uint64_t txg, open_txg;
1669 	int error;
1670 	vdev_t *rvd = spa->spa_root_vdev;
1671 	vdev_t *oldvd, *newvd, *newrootvd, *pvd, *tvd;
1672 	vdev_ops_t *pvops;
1673 
1674 	txg = spa_vdev_enter(spa);
1675 
1676 	oldvd = vdev_lookup_by_guid(rvd, guid);
1677 
1678 	if (oldvd == NULL)
1679 		return (spa_vdev_exit(spa, NULL, txg, ENODEV));
1680 
1681 	if (!oldvd->vdev_ops->vdev_op_leaf)
1682 		return (spa_vdev_exit(spa, NULL, txg, ENOTSUP));
1683 
1684 	pvd = oldvd->vdev_parent;
1685 
1686 	if ((error = spa_config_parse(spa, &newrootvd, nvroot, NULL, 0,
1687 	    VDEV_ALLOC_ADD)) != 0 || newrootvd->vdev_children != 1)
1688 		return (spa_vdev_exit(spa, newrootvd, txg, EINVAL));
1689 
1690 	newvd = newrootvd->vdev_child[0];
1691 
1692 	if (!newvd->vdev_ops->vdev_op_leaf)
1693 		return (spa_vdev_exit(spa, newrootvd, txg, EINVAL));
1694 
1695 	if ((error = vdev_create(newrootvd, txg, replacing)) != 0)
1696 		return (spa_vdev_exit(spa, newrootvd, txg, error));
1697 
1698 	if (!replacing) {
1699 		/*
1700 		 * For attach, the only allowable parent is a mirror or the root
1701 		 * vdev.
1702 		 */
1703 		if (pvd->vdev_ops != &vdev_mirror_ops &&
1704 		    pvd->vdev_ops != &vdev_root_ops)
1705 			return (spa_vdev_exit(spa, newrootvd, txg, ENOTSUP));
1706 
1707 		pvops = &vdev_mirror_ops;
1708 	} else {
1709 		/*
1710 		 * Active hot spares can only be replaced by inactive hot
1711 		 * spares.
1712 		 */
1713 		if (pvd->vdev_ops == &vdev_spare_ops &&
1714 		    pvd->vdev_child[1] == oldvd &&
1715 		    !spa_has_spare(spa, newvd->vdev_guid))
1716 			return (spa_vdev_exit(spa, newrootvd, txg, ENOTSUP));
1717 
1718 		/*
1719 		 * If the source is a hot spare, and the parent isn't already a
1720 		 * spare, then we want to create a new hot spare.  Otherwise, we
1721 		 * want to create a replacing vdev.  The user is not allowed to
1722 		 * attach to a spared vdev child unless the 'isspare' state is
1723 		 * the same (spare replaces spare, non-spare replaces
1724 		 * non-spare).
1725 		 */
1726 		if (pvd->vdev_ops == &vdev_replacing_ops)
1727 			return (spa_vdev_exit(spa, newrootvd, txg, ENOTSUP));
1728 		else if (pvd->vdev_ops == &vdev_spare_ops &&
1729 		    newvd->vdev_isspare != oldvd->vdev_isspare)
1730 			return (spa_vdev_exit(spa, newrootvd, txg, ENOTSUP));
1731 		else if (pvd->vdev_ops != &vdev_spare_ops &&
1732 		    newvd->vdev_isspare)
1733 			pvops = &vdev_spare_ops;
1734 		else
1735 			pvops = &vdev_replacing_ops;
1736 	}
1737 
1738 	/*
1739 	 * Compare the new device size with the replaceable/attachable
1740 	 * device size.
1741 	 */
1742 	if (newvd->vdev_psize < vdev_get_rsize(oldvd))
1743 		return (spa_vdev_exit(spa, newrootvd, txg, EOVERFLOW));
1744 
1745 	/*
1746 	 * The new device cannot have a higher alignment requirement
1747 	 * than the top-level vdev.
1748 	 */
1749 	if (newvd->vdev_ashift > oldvd->vdev_top->vdev_ashift)
1750 		return (spa_vdev_exit(spa, newrootvd, txg, EDOM));
1751 
1752 	/*
1753 	 * If this is an in-place replacement, update oldvd's path and devid
1754 	 * to make it distinguishable from newvd, and unopenable from now on.
1755 	 */
1756 	if (strcmp(oldvd->vdev_path, newvd->vdev_path) == 0) {
1757 		spa_strfree(oldvd->vdev_path);
1758 		oldvd->vdev_path = kmem_alloc(strlen(newvd->vdev_path) + 5,
1759 		    KM_SLEEP);
1760 		(void) sprintf(oldvd->vdev_path, "%s/%s",
1761 		    newvd->vdev_path, "old");
1762 		if (oldvd->vdev_devid != NULL) {
1763 			spa_strfree(oldvd->vdev_devid);
1764 			oldvd->vdev_devid = NULL;
1765 		}
1766 	}
1767 
1768 	/*
1769 	 * If the parent is not a mirror, or if we're replacing, insert the new
1770 	 * mirror/replacing/spare vdev above oldvd.
1771 	 */
1772 	if (pvd->vdev_ops != pvops)
1773 		pvd = vdev_add_parent(oldvd, pvops);
1774 
1775 	ASSERT(pvd->vdev_top->vdev_parent == rvd);
1776 	ASSERT(pvd->vdev_ops == pvops);
1777 	ASSERT(oldvd->vdev_parent == pvd);
1778 
1779 	/*
1780 	 * Extract the new device from its root and add it to pvd.
1781 	 */
1782 	vdev_remove_child(newrootvd, newvd);
1783 	newvd->vdev_id = pvd->vdev_children;
1784 	vdev_add_child(pvd, newvd);
1785 
1786 	/*
1787 	 * If newvd is smaller than oldvd, but larger than its rsize,
1788 	 * the addition of newvd may have decreased our parent's asize.
1789 	 */
1790 	pvd->vdev_asize = MIN(pvd->vdev_asize, newvd->vdev_asize);
1791 
1792 	tvd = newvd->vdev_top;
1793 	ASSERT(pvd->vdev_top == tvd);
1794 	ASSERT(tvd->vdev_parent == rvd);
1795 
1796 	vdev_config_dirty(tvd);
1797 
1798 	/*
1799 	 * Set newvd's DTL to [TXG_INITIAL, open_txg].  It will propagate
1800 	 * upward when spa_vdev_exit() calls vdev_dtl_reassess().
1801 	 */
1802 	open_txg = txg + TXG_CONCURRENT_STATES - 1;
1803 
1804 	mutex_enter(&newvd->vdev_dtl_lock);
1805 	space_map_add(&newvd->vdev_dtl_map, TXG_INITIAL,
1806 	    open_txg - TXG_INITIAL + 1);
1807 	mutex_exit(&newvd->vdev_dtl_lock);
1808 
1809 	if (newvd->vdev_isspare)
1810 		spa_spare_activate(newvd);
1811 
1812 	/*
1813 	 * Mark newvd's DTL dirty in this txg.
1814 	 */
1815 	vdev_dirty(tvd, VDD_DTL, newvd, txg);
1816 
1817 	(void) spa_vdev_exit(spa, newrootvd, open_txg, 0);
1818 
1819 	/*
1820 	 * Kick off a resilver to update newvd.
1821 	 */
1822 	VERIFY(spa_scrub(spa, POOL_SCRUB_RESILVER, B_TRUE) == 0);
1823 
1824 	return (0);
1825 }
1826 
1827 /*
1828  * Detach a device from a mirror or replacing vdev.
1829  * If 'replace_done' is specified, only detach if the parent
1830  * is a replacing vdev.
1831  */
1832 int
1833 spa_vdev_detach(spa_t *spa, uint64_t guid, int replace_done)
1834 {
1835 	uint64_t txg;
1836 	int c, t, error;
1837 	vdev_t *rvd = spa->spa_root_vdev;
1838 	vdev_t *vd, *pvd, *cvd, *tvd;
1839 	boolean_t unspare = B_FALSE;
1840 	uint64_t unspare_guid;
1841 
1842 	txg = spa_vdev_enter(spa);
1843 
1844 	vd = vdev_lookup_by_guid(rvd, guid);
1845 
1846 	if (vd == NULL)
1847 		return (spa_vdev_exit(spa, NULL, txg, ENODEV));
1848 
1849 	if (!vd->vdev_ops->vdev_op_leaf)
1850 		return (spa_vdev_exit(spa, NULL, txg, ENOTSUP));
1851 
1852 	pvd = vd->vdev_parent;
1853 
1854 	/*
1855 	 * If replace_done is specified, only remove this device if it's
1856 	 * the first child of a replacing vdev.  For the 'spare' vdev, either
1857 	 * disk can be removed.
1858 	 */
1859 	if (replace_done) {
1860 		if (pvd->vdev_ops == &vdev_replacing_ops) {
1861 			if (vd->vdev_id != 0)
1862 				return (spa_vdev_exit(spa, NULL, txg, ENOTSUP));
1863 		} else if (pvd->vdev_ops != &vdev_spare_ops) {
1864 			return (spa_vdev_exit(spa, NULL, txg, ENOTSUP));
1865 		}
1866 	}
1867 
1868 	ASSERT(pvd->vdev_ops != &vdev_spare_ops ||
1869 	    spa_version(spa) >= ZFS_VERSION_SPARES);
1870 
1871 	/*
1872 	 * Only mirror, replacing, and spare vdevs support detach.
1873 	 */
1874 	if (pvd->vdev_ops != &vdev_replacing_ops &&
1875 	    pvd->vdev_ops != &vdev_mirror_ops &&
1876 	    pvd->vdev_ops != &vdev_spare_ops)
1877 		return (spa_vdev_exit(spa, NULL, txg, ENOTSUP));
1878 
1879 	/*
1880 	 * If there's only one replica, you can't detach it.
1881 	 */
1882 	if (pvd->vdev_children <= 1)
1883 		return (spa_vdev_exit(spa, NULL, txg, EBUSY));
1884 
1885 	/*
1886 	 * If all siblings have non-empty DTLs, this device may have the only
1887 	 * valid copy of the data, which means we cannot safely detach it.
1888 	 *
1889 	 * XXX -- as in the vdev_offline() case, we really want a more
1890 	 * precise DTL check.
1891 	 */
1892 	for (c = 0; c < pvd->vdev_children; c++) {
1893 		uint64_t dirty;
1894 
1895 		cvd = pvd->vdev_child[c];
1896 		if (cvd == vd)
1897 			continue;
1898 		if (vdev_is_dead(cvd))
1899 			continue;
1900 		mutex_enter(&cvd->vdev_dtl_lock);
1901 		dirty = cvd->vdev_dtl_map.sm_space |
1902 		    cvd->vdev_dtl_scrub.sm_space;
1903 		mutex_exit(&cvd->vdev_dtl_lock);
1904 		if (!dirty)
1905 			break;
1906 	}
1907 
1908 	/*
1909 	 * If we are a replacing or spare vdev, then we can always detach the
1910 	 * latter child, as that is how one cancels the operation.
1911 	 */
1912 	if ((pvd->vdev_ops == &vdev_mirror_ops || vd->vdev_id != 1) &&
1913 	    c == pvd->vdev_children)
1914 		return (spa_vdev_exit(spa, NULL, txg, EBUSY));
1915 
1916 	/*
1917 	 * If we are detaching the original disk from a spare, then it implies
1918 	 * that the spare should become a real disk, and be removed from the
1919 	 * active spare list for the pool.
1920 	 */
1921 	if (pvd->vdev_ops == &vdev_spare_ops &&
1922 	    vd->vdev_id == 0)
1923 		unspare = B_TRUE;
1924 
1925 	/*
1926 	 * Erase the disk labels so the disk can be used for other things.
1927 	 * This must be done after all other error cases are handled,
1928 	 * but before we disembowel vd (so we can still do I/O to it).
1929 	 * But if we can't do it, don't treat the error as fatal --
1930 	 * it may be that the unwritability of the disk is the reason
1931 	 * it's being detached!
1932 	 */
1933 	error = vdev_label_init(vd, 0, VDEV_LABEL_REMOVE);
1934 
1935 	/*
1936 	 * Remove vd from its parent and compact the parent's children.
1937 	 */
1938 	vdev_remove_child(pvd, vd);
1939 	vdev_compact_children(pvd);
1940 
1941 	/*
1942 	 * Remember one of the remaining children so we can get tvd below.
1943 	 */
1944 	cvd = pvd->vdev_child[0];
1945 
1946 	/*
1947 	 * If we need to remove the remaining child from the list of hot spares,
1948 	 * do it now, marking the vdev as no longer a spare in the process.  We
1949 	 * must do this before vdev_remove_parent(), because that can change the
1950 	 * GUID if it creates a new toplevel GUID.
1951 	 */
1952 	if (unspare) {
1953 		ASSERT(cvd->vdev_isspare);
1954 		spa_spare_remove(cvd);
1955 		unspare_guid = cvd->vdev_guid;
1956 	}
1957 
1958 	/*
1959 	 * If the parent mirror/replacing vdev only has one child,
1960 	 * the parent is no longer needed.  Remove it from the tree.
1961 	 */
1962 	if (pvd->vdev_children == 1)
1963 		vdev_remove_parent(cvd);
1964 
1965 	/*
1966 	 * We don't set tvd until now because the parent we just removed
1967 	 * may have been the previous top-level vdev.
1968 	 */
1969 	tvd = cvd->vdev_top;
1970 	ASSERT(tvd->vdev_parent == rvd);
1971 
1972 	/*
1973 	 * Reevaluate the parent vdev state.
1974 	 */
1975 	vdev_propagate_state(cvd->vdev_parent);
1976 
1977 	/*
1978 	 * If the device we just detached was smaller than the others, it may be
1979 	 * possible to add metaslabs (i.e. grow the pool).  vdev_metaslab_init()
1980 	 * can't fail because the existing metaslabs are already in core, so
1981 	 * there's nothing to read from disk.
1982 	 */
1983 	VERIFY(vdev_metaslab_init(tvd, txg) == 0);
1984 
1985 	vdev_config_dirty(tvd);
1986 
1987 	/*
1988 	 * Mark vd's DTL as dirty in this txg.  vdev_dtl_sync() will see that
1989 	 * vd->vdev_detached is set and free vd's DTL object in syncing context.
1990 	 * But first make sure we're not on any *other* txg's DTL list, to
1991 	 * prevent vd from being accessed after it's freed.
1992 	 */
1993 	for (t = 0; t < TXG_SIZE; t++)
1994 		(void) txg_list_remove_this(&tvd->vdev_dtl_list, vd, t);
1995 	vd->vdev_detached = B_TRUE;
1996 	vdev_dirty(tvd, VDD_DTL, vd, txg);
1997 
1998 	error = spa_vdev_exit(spa, vd, txg, 0);
1999 
2000 	/*
2001 	 * If this was the removal of the original device in a hot spare vdev,
2002 	 * then we want to go through and remove the device from the hot spare
2003 	 * list of every other pool.
2004 	 */
2005 	if (unspare) {
2006 		spa = NULL;
2007 		mutex_enter(&spa_namespace_lock);
2008 		while ((spa = spa_next(spa)) != NULL) {
2009 			if (spa->spa_state != POOL_STATE_ACTIVE)
2010 				continue;
2011 
2012 			(void) spa_vdev_remove(spa, unspare_guid, B_TRUE);
2013 		}
2014 		mutex_exit(&spa_namespace_lock);
2015 	}
2016 
2017 	return (error);
2018 }
2019 
2020 /*
2021  * Remove a device from the pool.  Currently, this supports removing only hot
2022  * spares.
2023  */
2024 int
2025 spa_vdev_remove(spa_t *spa, uint64_t guid, boolean_t unspare)
2026 {
2027 	vdev_t *vd;
2028 	nvlist_t **spares, *nv, **newspares;
2029 	uint_t i, j, nspares;
2030 	int ret = 0;
2031 
2032 	spa_config_enter(spa, RW_WRITER, FTAG);
2033 
2034 	vd = spa_lookup_by_guid(spa, guid);
2035 
2036 	nv = NULL;
2037 	if (spa->spa_spares != NULL &&
2038 	    nvlist_lookup_nvlist_array(spa->spa_sparelist, ZPOOL_CONFIG_SPARES,
2039 	    &spares, &nspares) == 0) {
2040 		for (i = 0; i < nspares; i++) {
2041 			uint64_t theguid;
2042 
2043 			VERIFY(nvlist_lookup_uint64(spares[i],
2044 			    ZPOOL_CONFIG_GUID, &theguid) == 0);
2045 			if (theguid == guid) {
2046 				nv = spares[i];
2047 				break;
2048 			}
2049 		}
2050 	}
2051 
2052 	/*
2053 	 * We only support removing a hot spare, and only if it's not currently
2054 	 * in use in this pool.
2055 	 */
2056 	if (nv == NULL && vd == NULL) {
2057 		ret = ENOENT;
2058 		goto out;
2059 	}
2060 
2061 	if (nv == NULL && vd != NULL) {
2062 		ret = ENOTSUP;
2063 		goto out;
2064 	}
2065 
2066 	if (!unspare && nv != NULL && vd != NULL) {
2067 		ret = EBUSY;
2068 		goto out;
2069 	}
2070 
2071 	if (nspares == 1) {
2072 		newspares = NULL;
2073 	} else {
2074 		newspares = kmem_alloc((nspares - 1) * sizeof (void *),
2075 		    KM_SLEEP);
2076 		for (i = 0, j = 0; i < nspares; i++) {
2077 			if (spares[i] != nv)
2078 				VERIFY(nvlist_dup(spares[i],
2079 				    &newspares[j++], KM_SLEEP) == 0);
2080 		}
2081 	}
2082 
2083 	VERIFY(nvlist_remove(spa->spa_sparelist, ZPOOL_CONFIG_SPARES,
2084 	    DATA_TYPE_NVLIST_ARRAY) == 0);
2085 	VERIFY(nvlist_add_nvlist_array(spa->spa_sparelist, ZPOOL_CONFIG_SPARES,
2086 	    newspares, nspares - 1) == 0);
2087 	for (i = 0; i < nspares - 1; i++)
2088 		nvlist_free(newspares[i]);
2089 	kmem_free(newspares, (nspares - 1) * sizeof (void *));
2090 	spa_load_spares(spa);
2091 	spa->spa_sync_spares = B_TRUE;
2092 
2093 out:
2094 	spa_config_exit(spa, FTAG);
2095 
2096 	return (ret);
2097 }
2098 
2099 /*
2100  * Find any device that's done replacing, so we can detach it.
2101  */
2102 static vdev_t *
2103 spa_vdev_replace_done_hunt(vdev_t *vd)
2104 {
2105 	vdev_t *newvd, *oldvd;
2106 	int c;
2107 
2108 	for (c = 0; c < vd->vdev_children; c++) {
2109 		oldvd = spa_vdev_replace_done_hunt(vd->vdev_child[c]);
2110 		if (oldvd != NULL)
2111 			return (oldvd);
2112 	}
2113 
2114 	if (vd->vdev_ops == &vdev_replacing_ops && vd->vdev_children == 2) {
2115 		oldvd = vd->vdev_child[0];
2116 		newvd = vd->vdev_child[1];
2117 
2118 		mutex_enter(&newvd->vdev_dtl_lock);
2119 		if (newvd->vdev_dtl_map.sm_space == 0 &&
2120 		    newvd->vdev_dtl_scrub.sm_space == 0) {
2121 			mutex_exit(&newvd->vdev_dtl_lock);
2122 			return (oldvd);
2123 		}
2124 		mutex_exit(&newvd->vdev_dtl_lock);
2125 	}
2126 
2127 	return (NULL);
2128 }
2129 
2130 static void
2131 spa_vdev_replace_done(spa_t *spa)
2132 {
2133 	vdev_t *vd;
2134 	vdev_t *pvd;
2135 	uint64_t guid;
2136 	uint64_t pguid = 0;
2137 
2138 	spa_config_enter(spa, RW_READER, FTAG);
2139 
2140 	while ((vd = spa_vdev_replace_done_hunt(spa->spa_root_vdev)) != NULL) {
2141 		guid = vd->vdev_guid;
2142 		/*
2143 		 * If we have just finished replacing a hot spared device, then
2144 		 * we need to detach the parent's first child (the original hot
2145 		 * spare) as well.
2146 		 */
2147 		pvd = vd->vdev_parent;
2148 		if (pvd->vdev_parent->vdev_ops == &vdev_spare_ops &&
2149 		    pvd->vdev_id == 0) {
2150 			ASSERT(pvd->vdev_ops == &vdev_replacing_ops);
2151 			ASSERT(pvd->vdev_parent->vdev_children == 2);
2152 			pguid = pvd->vdev_parent->vdev_child[1]->vdev_guid;
2153 		}
2154 		spa_config_exit(spa, FTAG);
2155 		if (spa_vdev_detach(spa, guid, B_TRUE) != 0)
2156 			return;
2157 		if (pguid != 0 && spa_vdev_detach(spa, pguid, B_TRUE) != 0)
2158 			return;
2159 		spa_config_enter(spa, RW_READER, FTAG);
2160 	}
2161 
2162 	spa_config_exit(spa, FTAG);
2163 }
2164 
2165 /*
2166  * Update the stored path for this vdev.  Dirty the vdev configuration, relying
2167  * on spa_vdev_enter/exit() to synchronize the labels and cache.
2168  */
2169 int
2170 spa_vdev_setpath(spa_t *spa, uint64_t guid, const char *newpath)
2171 {
2172 	vdev_t *rvd, *vd;
2173 	uint64_t txg;
2174 
2175 	rvd = spa->spa_root_vdev;
2176 
2177 	txg = spa_vdev_enter(spa);
2178 
2179 	if ((vd = vdev_lookup_by_guid(rvd, guid)) == NULL) {
2180 		/*
2181 		 * Determine if this is a reference to a hot spare.  In that
2182 		 * case, update the path as stored in the spare list.
2183 		 */
2184 		nvlist_t **spares;
2185 		uint_t i, nspares;
2186 		if (spa->spa_sparelist != NULL) {
2187 			VERIFY(nvlist_lookup_nvlist_array(spa->spa_sparelist,
2188 			    ZPOOL_CONFIG_SPARES, &spares, &nspares) == 0);
2189 			for (i = 0; i < nspares; i++) {
2190 				uint64_t theguid;
2191 				VERIFY(nvlist_lookup_uint64(spares[i],
2192 				    ZPOOL_CONFIG_GUID, &theguid) == 0);
2193 				if (theguid == guid)
2194 					break;
2195 			}
2196 
2197 			if (i == nspares)
2198 				return (spa_vdev_exit(spa, NULL, txg, ENOENT));
2199 
2200 			VERIFY(nvlist_add_string(spares[i],
2201 			    ZPOOL_CONFIG_PATH, newpath) == 0);
2202 			spa_load_spares(spa);
2203 			spa->spa_sync_spares = B_TRUE;
2204 			return (spa_vdev_exit(spa, NULL, txg, 0));
2205 		} else {
2206 			return (spa_vdev_exit(spa, NULL, txg, ENOENT));
2207 		}
2208 	}
2209 
2210 	if (!vd->vdev_ops->vdev_op_leaf)
2211 		return (spa_vdev_exit(spa, NULL, txg, ENOTSUP));
2212 
2213 	spa_strfree(vd->vdev_path);
2214 	vd->vdev_path = spa_strdup(newpath);
2215 
2216 	vdev_config_dirty(vd->vdev_top);
2217 
2218 	return (spa_vdev_exit(spa, NULL, txg, 0));
2219 }
2220 
2221 /*
2222  * ==========================================================================
2223  * SPA Scrubbing
2224  * ==========================================================================
2225  */
2226 
2227 static void
2228 spa_scrub_io_done(zio_t *zio)
2229 {
2230 	spa_t *spa = zio->io_spa;
2231 
2232 	zio_data_buf_free(zio->io_data, zio->io_size);
2233 
2234 	mutex_enter(&spa->spa_scrub_lock);
2235 	if (zio->io_error && !(zio->io_flags & ZIO_FLAG_SPECULATIVE)) {
2236 		vdev_t *vd = zio->io_vd ? zio->io_vd : spa->spa_root_vdev;
2237 		spa->spa_scrub_errors++;
2238 		mutex_enter(&vd->vdev_stat_lock);
2239 		vd->vdev_stat.vs_scrub_errors++;
2240 		mutex_exit(&vd->vdev_stat_lock);
2241 	}
2242 
2243 	if (--spa->spa_scrub_inflight < spa->spa_scrub_maxinflight)
2244 		cv_broadcast(&spa->spa_scrub_io_cv);
2245 
2246 	ASSERT(spa->spa_scrub_inflight >= 0);
2247 
2248 	mutex_exit(&spa->spa_scrub_lock);
2249 }
2250 
2251 static void
2252 spa_scrub_io_start(spa_t *spa, blkptr_t *bp, int priority, int flags,
2253     zbookmark_t *zb)
2254 {
2255 	size_t size = BP_GET_LSIZE(bp);
2256 	void *data;
2257 
2258 	mutex_enter(&spa->spa_scrub_lock);
2259 	/*
2260 	 * Do not give too much work to vdev(s).
2261 	 */
2262 	while (spa->spa_scrub_inflight >= spa->spa_scrub_maxinflight) {
2263 		cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock);
2264 	}
2265 	spa->spa_scrub_inflight++;
2266 	mutex_exit(&spa->spa_scrub_lock);
2267 
2268 	data = zio_data_buf_alloc(size);
2269 
2270 	if (zb->zb_level == -1 && BP_GET_TYPE(bp) != DMU_OT_OBJSET)
2271 		flags |= ZIO_FLAG_SPECULATIVE;	/* intent log block */
2272 
2273 	flags |= ZIO_FLAG_SCRUB_THREAD | ZIO_FLAG_CANFAIL;
2274 
2275 	zio_nowait(zio_read(NULL, spa, bp, data, size,
2276 	    spa_scrub_io_done, NULL, priority, flags, zb));
2277 }
2278 
2279 /* ARGSUSED */
2280 static int
2281 spa_scrub_cb(traverse_blk_cache_t *bc, spa_t *spa, void *a)
2282 {
2283 	blkptr_t *bp = &bc->bc_blkptr;
2284 	vdev_t *vd = spa->spa_root_vdev;
2285 	dva_t *dva = bp->blk_dva;
2286 	int needs_resilver = B_FALSE;
2287 	int d;
2288 
2289 	if (bc->bc_errno) {
2290 		/*
2291 		 * We can't scrub this block, but we can continue to scrub
2292 		 * the rest of the pool.  Note the error and move along.
2293 		 */
2294 		mutex_enter(&spa->spa_scrub_lock);
2295 		spa->spa_scrub_errors++;
2296 		mutex_exit(&spa->spa_scrub_lock);
2297 
2298 		mutex_enter(&vd->vdev_stat_lock);
2299 		vd->vdev_stat.vs_scrub_errors++;
2300 		mutex_exit(&vd->vdev_stat_lock);
2301 
2302 		return (ERESTART);
2303 	}
2304 
2305 	ASSERT(bp->blk_birth < spa->spa_scrub_maxtxg);
2306 
2307 	for (d = 0; d < BP_GET_NDVAS(bp); d++) {
2308 		vd = vdev_lookup_top(spa, DVA_GET_VDEV(&dva[d]));
2309 
2310 		ASSERT(vd != NULL);
2311 
2312 		/*
2313 		 * Keep track of how much data we've examined so that
2314 		 * zpool(1M) status can make useful progress reports.
2315 		 */
2316 		mutex_enter(&vd->vdev_stat_lock);
2317 		vd->vdev_stat.vs_scrub_examined += DVA_GET_ASIZE(&dva[d]);
2318 		mutex_exit(&vd->vdev_stat_lock);
2319 
2320 		if (spa->spa_scrub_type == POOL_SCRUB_RESILVER) {
2321 			if (DVA_GET_GANG(&dva[d])) {
2322 				/*
2323 				 * Gang members may be spread across multiple
2324 				 * vdevs, so the best we can do is look at the
2325 				 * pool-wide DTL.
2326 				 * XXX -- it would be better to change our
2327 				 * allocation policy to ensure that this can't
2328 				 * happen.
2329 				 */
2330 				vd = spa->spa_root_vdev;
2331 			}
2332 			if (vdev_dtl_contains(&vd->vdev_dtl_map,
2333 			    bp->blk_birth, 1))
2334 				needs_resilver = B_TRUE;
2335 		}
2336 	}
2337 
2338 	if (spa->spa_scrub_type == POOL_SCRUB_EVERYTHING)
2339 		spa_scrub_io_start(spa, bp, ZIO_PRIORITY_SCRUB,
2340 		    ZIO_FLAG_SCRUB, &bc->bc_bookmark);
2341 	else if (needs_resilver)
2342 		spa_scrub_io_start(spa, bp, ZIO_PRIORITY_RESILVER,
2343 		    ZIO_FLAG_RESILVER, &bc->bc_bookmark);
2344 
2345 	return (0);
2346 }
2347 
2348 static void
2349 spa_scrub_thread(spa_t *spa)
2350 {
2351 	callb_cpr_t cprinfo;
2352 	traverse_handle_t *th = spa->spa_scrub_th;
2353 	vdev_t *rvd = spa->spa_root_vdev;
2354 	pool_scrub_type_t scrub_type = spa->spa_scrub_type;
2355 	int error = 0;
2356 	boolean_t complete;
2357 
2358 	CALLB_CPR_INIT(&cprinfo, &spa->spa_scrub_lock, callb_generic_cpr, FTAG);
2359 
2360 	/*
2361 	 * If we're restarting due to a snapshot create/delete,
2362 	 * wait for that to complete.
2363 	 */
2364 	txg_wait_synced(spa_get_dsl(spa), 0);
2365 
2366 	dprintf("start %s mintxg=%llu maxtxg=%llu\n",
2367 	    scrub_type == POOL_SCRUB_RESILVER ? "resilver" : "scrub",
2368 	    spa->spa_scrub_mintxg, spa->spa_scrub_maxtxg);
2369 
2370 	spa_config_enter(spa, RW_WRITER, FTAG);
2371 	vdev_reopen(rvd);		/* purge all vdev caches */
2372 	vdev_config_dirty(rvd);		/* rewrite all disk labels */
2373 	vdev_scrub_stat_update(rvd, scrub_type, B_FALSE);
2374 	spa_config_exit(spa, FTAG);
2375 
2376 	mutex_enter(&spa->spa_scrub_lock);
2377 	spa->spa_scrub_errors = 0;
2378 	spa->spa_scrub_active = 1;
2379 	ASSERT(spa->spa_scrub_inflight == 0);
2380 
2381 	while (!spa->spa_scrub_stop) {
2382 		CALLB_CPR_SAFE_BEGIN(&cprinfo);
2383 		while (spa->spa_scrub_suspended) {
2384 			spa->spa_scrub_active = 0;
2385 			cv_broadcast(&spa->spa_scrub_cv);
2386 			cv_wait(&spa->spa_scrub_cv, &spa->spa_scrub_lock);
2387 			spa->spa_scrub_active = 1;
2388 		}
2389 		CALLB_CPR_SAFE_END(&cprinfo, &spa->spa_scrub_lock);
2390 
2391 		if (spa->spa_scrub_restart_txg != 0)
2392 			break;
2393 
2394 		mutex_exit(&spa->spa_scrub_lock);
2395 		error = traverse_more(th);
2396 		mutex_enter(&spa->spa_scrub_lock);
2397 		if (error != EAGAIN)
2398 			break;
2399 	}
2400 
2401 	while (spa->spa_scrub_inflight)
2402 		cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock);
2403 
2404 	spa->spa_scrub_active = 0;
2405 	cv_broadcast(&spa->spa_scrub_cv);
2406 
2407 	mutex_exit(&spa->spa_scrub_lock);
2408 
2409 	spa_config_enter(spa, RW_WRITER, FTAG);
2410 
2411 	mutex_enter(&spa->spa_scrub_lock);
2412 
2413 	/*
2414 	 * Note: we check spa_scrub_restart_txg under both spa_scrub_lock
2415 	 * AND the spa config lock to synchronize with any config changes
2416 	 * that revise the DTLs under spa_vdev_enter() / spa_vdev_exit().
2417 	 */
2418 	if (spa->spa_scrub_restart_txg != 0)
2419 		error = ERESTART;
2420 
2421 	if (spa->spa_scrub_stop)
2422 		error = EINTR;
2423 
2424 	/*
2425 	 * Even if there were uncorrectable errors, we consider the scrub
2426 	 * completed.  The downside is that if there is a transient error during
2427 	 * a resilver, we won't resilver the data properly to the target.  But
2428 	 * if the damage is permanent (more likely) we will resilver forever,
2429 	 * which isn't really acceptable.  Since there is enough information for
2430 	 * the user to know what has failed and why, this seems like a more
2431 	 * tractable approach.
2432 	 */
2433 	complete = (error == 0);
2434 
2435 	dprintf("end %s to maxtxg=%llu %s, traverse=%d, %llu errors, stop=%u\n",
2436 	    scrub_type == POOL_SCRUB_RESILVER ? "resilver" : "scrub",
2437 	    spa->spa_scrub_maxtxg, complete ? "done" : "FAILED",
2438 	    error, spa->spa_scrub_errors, spa->spa_scrub_stop);
2439 
2440 	mutex_exit(&spa->spa_scrub_lock);
2441 
2442 	/*
2443 	 * If the scrub/resilver completed, update all DTLs to reflect this.
2444 	 * Whether it succeeded or not, vacate all temporary scrub DTLs.
2445 	 */
2446 	vdev_dtl_reassess(rvd, spa_last_synced_txg(spa) + 1,
2447 	    complete ? spa->spa_scrub_maxtxg : 0, B_TRUE);
2448 	vdev_scrub_stat_update(rvd, POOL_SCRUB_NONE, complete);
2449 	spa_errlog_rotate(spa);
2450 
2451 	spa_config_exit(spa, FTAG);
2452 
2453 	mutex_enter(&spa->spa_scrub_lock);
2454 
2455 	/*
2456 	 * We may have finished replacing a device.
2457 	 * Let the async thread assess this and handle the detach.
2458 	 */
2459 	spa_async_request(spa, SPA_ASYNC_REPLACE_DONE);
2460 
2461 	/*
2462 	 * If we were told to restart, our final act is to start a new scrub.
2463 	 */
2464 	if (error == ERESTART)
2465 		spa_async_request(spa, scrub_type == POOL_SCRUB_RESILVER ?
2466 		    SPA_ASYNC_RESILVER : SPA_ASYNC_SCRUB);
2467 
2468 	spa->spa_scrub_type = POOL_SCRUB_NONE;
2469 	spa->spa_scrub_active = 0;
2470 	spa->spa_scrub_thread = NULL;
2471 	cv_broadcast(&spa->spa_scrub_cv);
2472 	CALLB_CPR_EXIT(&cprinfo);	/* drops &spa->spa_scrub_lock */
2473 	thread_exit();
2474 }
2475 
2476 void
2477 spa_scrub_suspend(spa_t *spa)
2478 {
2479 	mutex_enter(&spa->spa_scrub_lock);
2480 	spa->spa_scrub_suspended++;
2481 	while (spa->spa_scrub_active) {
2482 		cv_broadcast(&spa->spa_scrub_cv);
2483 		cv_wait(&spa->spa_scrub_cv, &spa->spa_scrub_lock);
2484 	}
2485 	while (spa->spa_scrub_inflight)
2486 		cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock);
2487 	mutex_exit(&spa->spa_scrub_lock);
2488 }
2489 
2490 void
2491 spa_scrub_resume(spa_t *spa)
2492 {
2493 	mutex_enter(&spa->spa_scrub_lock);
2494 	ASSERT(spa->spa_scrub_suspended != 0);
2495 	if (--spa->spa_scrub_suspended == 0)
2496 		cv_broadcast(&spa->spa_scrub_cv);
2497 	mutex_exit(&spa->spa_scrub_lock);
2498 }
2499 
2500 void
2501 spa_scrub_restart(spa_t *spa, uint64_t txg)
2502 {
2503 	/*
2504 	 * Something happened (e.g. snapshot create/delete) that means
2505 	 * we must restart any in-progress scrubs.  The itinerary will
2506 	 * fix this properly.
2507 	 */
2508 	mutex_enter(&spa->spa_scrub_lock);
2509 	spa->spa_scrub_restart_txg = txg;
2510 	mutex_exit(&spa->spa_scrub_lock);
2511 }
2512 
2513 int
2514 spa_scrub(spa_t *spa, pool_scrub_type_t type, boolean_t force)
2515 {
2516 	space_seg_t *ss;
2517 	uint64_t mintxg, maxtxg;
2518 	vdev_t *rvd = spa->spa_root_vdev;
2519 
2520 	if ((uint_t)type >= POOL_SCRUB_TYPES)
2521 		return (ENOTSUP);
2522 
2523 	mutex_enter(&spa->spa_scrub_lock);
2524 
2525 	/*
2526 	 * If there's a scrub or resilver already in progress, stop it.
2527 	 */
2528 	while (spa->spa_scrub_thread != NULL) {
2529 		/*
2530 		 * Don't stop a resilver unless forced.
2531 		 */
2532 		if (spa->spa_scrub_type == POOL_SCRUB_RESILVER && !force) {
2533 			mutex_exit(&spa->spa_scrub_lock);
2534 			return (EBUSY);
2535 		}
2536 		spa->spa_scrub_stop = 1;
2537 		cv_broadcast(&spa->spa_scrub_cv);
2538 		cv_wait(&spa->spa_scrub_cv, &spa->spa_scrub_lock);
2539 	}
2540 
2541 	/*
2542 	 * Terminate the previous traverse.
2543 	 */
2544 	if (spa->spa_scrub_th != NULL) {
2545 		traverse_fini(spa->spa_scrub_th);
2546 		spa->spa_scrub_th = NULL;
2547 	}
2548 
2549 	if (rvd == NULL) {
2550 		ASSERT(spa->spa_scrub_stop == 0);
2551 		ASSERT(spa->spa_scrub_type == type);
2552 		ASSERT(spa->spa_scrub_restart_txg == 0);
2553 		mutex_exit(&spa->spa_scrub_lock);
2554 		return (0);
2555 	}
2556 
2557 	mintxg = TXG_INITIAL - 1;
2558 	maxtxg = spa_last_synced_txg(spa) + 1;
2559 
2560 	mutex_enter(&rvd->vdev_dtl_lock);
2561 
2562 	if (rvd->vdev_dtl_map.sm_space == 0) {
2563 		/*
2564 		 * The pool-wide DTL is empty.
2565 		 * If this is a resilver, there's nothing to do except
2566 		 * check whether any in-progress replacements have completed.
2567 		 */
2568 		if (type == POOL_SCRUB_RESILVER) {
2569 			type = POOL_SCRUB_NONE;
2570 			spa_async_request(spa, SPA_ASYNC_REPLACE_DONE);
2571 		}
2572 	} else {
2573 		/*
2574 		 * The pool-wide DTL is non-empty.
2575 		 * If this is a normal scrub, upgrade to a resilver instead.
2576 		 */
2577 		if (type == POOL_SCRUB_EVERYTHING)
2578 			type = POOL_SCRUB_RESILVER;
2579 	}
2580 
2581 	if (type == POOL_SCRUB_RESILVER) {
2582 		/*
2583 		 * Determine the resilvering boundaries.
2584 		 *
2585 		 * Note: (mintxg, maxtxg) is an open interval,
2586 		 * i.e. mintxg and maxtxg themselves are not included.
2587 		 *
2588 		 * Note: for maxtxg, we MIN with spa_last_synced_txg(spa) + 1
2589 		 * so we don't claim to resilver a txg that's still changing.
2590 		 */
2591 		ss = avl_first(&rvd->vdev_dtl_map.sm_root);
2592 		mintxg = ss->ss_start - 1;
2593 		ss = avl_last(&rvd->vdev_dtl_map.sm_root);
2594 		maxtxg = MIN(ss->ss_end, maxtxg);
2595 	}
2596 
2597 	mutex_exit(&rvd->vdev_dtl_lock);
2598 
2599 	spa->spa_scrub_stop = 0;
2600 	spa->spa_scrub_type = type;
2601 	spa->spa_scrub_restart_txg = 0;
2602 
2603 	if (type != POOL_SCRUB_NONE) {
2604 		spa->spa_scrub_mintxg = mintxg;
2605 		spa->spa_scrub_maxtxg = maxtxg;
2606 		spa->spa_scrub_th = traverse_init(spa, spa_scrub_cb, NULL,
2607 		    ADVANCE_PRE | ADVANCE_PRUNE | ADVANCE_ZIL,
2608 		    ZIO_FLAG_CANFAIL);
2609 		traverse_add_pool(spa->spa_scrub_th, mintxg, maxtxg);
2610 		spa->spa_scrub_thread = thread_create(NULL, 0,
2611 		    spa_scrub_thread, spa, 0, &p0, TS_RUN, minclsyspri);
2612 	}
2613 
2614 	mutex_exit(&spa->spa_scrub_lock);
2615 
2616 	return (0);
2617 }
2618 
2619 /*
2620  * ==========================================================================
2621  * SPA async task processing
2622  * ==========================================================================
2623  */
2624 
2625 static void
2626 spa_async_reopen(spa_t *spa)
2627 {
2628 	vdev_t *rvd = spa->spa_root_vdev;
2629 	vdev_t *tvd;
2630 	int c;
2631 
2632 	spa_config_enter(spa, RW_WRITER, FTAG);
2633 
2634 	for (c = 0; c < rvd->vdev_children; c++) {
2635 		tvd = rvd->vdev_child[c];
2636 		if (tvd->vdev_reopen_wanted) {
2637 			tvd->vdev_reopen_wanted = 0;
2638 			vdev_reopen(tvd);
2639 		}
2640 	}
2641 
2642 	spa_config_exit(spa, FTAG);
2643 }
2644 
2645 static void
2646 spa_async_thread(spa_t *spa)
2647 {
2648 	int tasks;
2649 
2650 	ASSERT(spa->spa_sync_on);
2651 
2652 	mutex_enter(&spa->spa_async_lock);
2653 	tasks = spa->spa_async_tasks;
2654 	spa->spa_async_tasks = 0;
2655 	mutex_exit(&spa->spa_async_lock);
2656 
2657 	/*
2658 	 * See if the config needs to be updated.
2659 	 */
2660 	if (tasks & SPA_ASYNC_CONFIG_UPDATE) {
2661 		mutex_enter(&spa_namespace_lock);
2662 		spa_config_update(spa, SPA_CONFIG_UPDATE_POOL);
2663 		mutex_exit(&spa_namespace_lock);
2664 	}
2665 
2666 	/*
2667 	 * See if any devices need to be reopened.
2668 	 */
2669 	if (tasks & SPA_ASYNC_REOPEN)
2670 		spa_async_reopen(spa);
2671 
2672 	/*
2673 	 * If any devices are done replacing, detach them.
2674 	 */
2675 	if (tasks & SPA_ASYNC_REPLACE_DONE)
2676 		spa_vdev_replace_done(spa);
2677 
2678 	/*
2679 	 * Kick off a scrub.
2680 	 */
2681 	if (tasks & SPA_ASYNC_SCRUB)
2682 		VERIFY(spa_scrub(spa, POOL_SCRUB_EVERYTHING, B_TRUE) == 0);
2683 
2684 	/*
2685 	 * Kick off a resilver.
2686 	 */
2687 	if (tasks & SPA_ASYNC_RESILVER)
2688 		VERIFY(spa_scrub(spa, POOL_SCRUB_RESILVER, B_TRUE) == 0);
2689 
2690 	/*
2691 	 * Let the world know that we're done.
2692 	 */
2693 	mutex_enter(&spa->spa_async_lock);
2694 	spa->spa_async_thread = NULL;
2695 	cv_broadcast(&spa->spa_async_cv);
2696 	mutex_exit(&spa->spa_async_lock);
2697 	thread_exit();
2698 }
2699 
2700 void
2701 spa_async_suspend(spa_t *spa)
2702 {
2703 	mutex_enter(&spa->spa_async_lock);
2704 	spa->spa_async_suspended++;
2705 	while (spa->spa_async_thread != NULL)
2706 		cv_wait(&spa->spa_async_cv, &spa->spa_async_lock);
2707 	mutex_exit(&spa->spa_async_lock);
2708 }
2709 
2710 void
2711 spa_async_resume(spa_t *spa)
2712 {
2713 	mutex_enter(&spa->spa_async_lock);
2714 	ASSERT(spa->spa_async_suspended != 0);
2715 	spa->spa_async_suspended--;
2716 	mutex_exit(&spa->spa_async_lock);
2717 }
2718 
2719 static void
2720 spa_async_dispatch(spa_t *spa)
2721 {
2722 	mutex_enter(&spa->spa_async_lock);
2723 	if (spa->spa_async_tasks && !spa->spa_async_suspended &&
2724 	    spa->spa_async_thread == NULL &&
2725 	    rootdir != NULL && !vn_is_readonly(rootdir))
2726 		spa->spa_async_thread = thread_create(NULL, 0,
2727 		    spa_async_thread, spa, 0, &p0, TS_RUN, maxclsyspri);
2728 	mutex_exit(&spa->spa_async_lock);
2729 }
2730 
2731 void
2732 spa_async_request(spa_t *spa, int task)
2733 {
2734 	mutex_enter(&spa->spa_async_lock);
2735 	spa->spa_async_tasks |= task;
2736 	mutex_exit(&spa->spa_async_lock);
2737 }
2738 
2739 /*
2740  * ==========================================================================
2741  * SPA syncing routines
2742  * ==========================================================================
2743  */
2744 
2745 static void
2746 spa_sync_deferred_frees(spa_t *spa, uint64_t txg)
2747 {
2748 	bplist_t *bpl = &spa->spa_sync_bplist;
2749 	dmu_tx_t *tx;
2750 	blkptr_t blk;
2751 	uint64_t itor = 0;
2752 	zio_t *zio;
2753 	int error;
2754 	uint8_t c = 1;
2755 
2756 	zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CONFIG_HELD);
2757 
2758 	while (bplist_iterate(bpl, &itor, &blk) == 0)
2759 		zio_nowait(zio_free(zio, spa, txg, &blk, NULL, NULL));
2760 
2761 	error = zio_wait(zio);
2762 	ASSERT3U(error, ==, 0);
2763 
2764 	tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg);
2765 	bplist_vacate(bpl, tx);
2766 
2767 	/*
2768 	 * Pre-dirty the first block so we sync to convergence faster.
2769 	 * (Usually only the first block is needed.)
2770 	 */
2771 	dmu_write(spa->spa_meta_objset, spa->spa_sync_bplist_obj, 0, 1, &c, tx);
2772 	dmu_tx_commit(tx);
2773 }
2774 
2775 static void
2776 spa_sync_nvlist(spa_t *spa, uint64_t obj, nvlist_t *nv, dmu_tx_t *tx)
2777 {
2778 	char *packed = NULL;
2779 	size_t nvsize = 0;
2780 	dmu_buf_t *db;
2781 
2782 	VERIFY(nvlist_size(nv, &nvsize, NV_ENCODE_XDR) == 0);
2783 
2784 	packed = kmem_alloc(nvsize, KM_SLEEP);
2785 
2786 	VERIFY(nvlist_pack(nv, &packed, &nvsize, NV_ENCODE_XDR,
2787 	    KM_SLEEP) == 0);
2788 
2789 	dmu_write(spa->spa_meta_objset, obj, 0, nvsize, packed, tx);
2790 
2791 	kmem_free(packed, nvsize);
2792 
2793 	VERIFY(0 == dmu_bonus_hold(spa->spa_meta_objset, obj, FTAG, &db));
2794 	dmu_buf_will_dirty(db, tx);
2795 	*(uint64_t *)db->db_data = nvsize;
2796 	dmu_buf_rele(db, FTAG);
2797 }
2798 
2799 static void
2800 spa_sync_spares(spa_t *spa, dmu_tx_t *tx)
2801 {
2802 	nvlist_t *nvroot;
2803 	nvlist_t **spares;
2804 	int i;
2805 
2806 	if (!spa->spa_sync_spares)
2807 		return;
2808 
2809 	/*
2810 	 * Update the MOS nvlist describing the list of available spares.
2811 	 * spa_validate_spares() will have already made sure this nvlist is
2812 	 * valid and the vdevs are labelled appropriately.
2813 	 */
2814 	if (spa->spa_spares_object == 0) {
2815 		spa->spa_spares_object = dmu_object_alloc(spa->spa_meta_objset,
2816 		    DMU_OT_PACKED_NVLIST, 1 << 14,
2817 		    DMU_OT_PACKED_NVLIST_SIZE, sizeof (uint64_t), tx);
2818 		VERIFY(zap_update(spa->spa_meta_objset,
2819 		    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_SPARES,
2820 		    sizeof (uint64_t), 1, &spa->spa_spares_object, tx) == 0);
2821 	}
2822 
2823 	VERIFY(nvlist_alloc(&nvroot, NV_UNIQUE_NAME, KM_SLEEP) == 0);
2824 	if (spa->spa_nspares == 0) {
2825 		VERIFY(nvlist_add_nvlist_array(nvroot, ZPOOL_CONFIG_SPARES,
2826 		    NULL, 0) == 0);
2827 	} else {
2828 		spares = kmem_alloc(spa->spa_nspares * sizeof (void *),
2829 		    KM_SLEEP);
2830 		for (i = 0; i < spa->spa_nspares; i++)
2831 			spares[i] = vdev_config_generate(spa,
2832 			    spa->spa_spares[i], B_FALSE, B_TRUE);
2833 		VERIFY(nvlist_add_nvlist_array(nvroot, ZPOOL_CONFIG_SPARES,
2834 		    spares, spa->spa_nspares) == 0);
2835 		for (i = 0; i < spa->spa_nspares; i++)
2836 			nvlist_free(spares[i]);
2837 		kmem_free(spares, spa->spa_nspares * sizeof (void *));
2838 	}
2839 
2840 	spa_sync_nvlist(spa, spa->spa_spares_object, nvroot, tx);
2841 	nvlist_free(nvroot);
2842 
2843 	spa->spa_sync_spares = B_FALSE;
2844 }
2845 
2846 static void
2847 spa_sync_config_object(spa_t *spa, dmu_tx_t *tx)
2848 {
2849 	nvlist_t *config;
2850 
2851 	if (list_is_empty(&spa->spa_dirty_list))
2852 		return;
2853 
2854 	config = spa_config_generate(spa, NULL, dmu_tx_get_txg(tx), B_FALSE);
2855 
2856 	if (spa->spa_config_syncing)
2857 		nvlist_free(spa->spa_config_syncing);
2858 	spa->spa_config_syncing = config;
2859 
2860 	spa_sync_nvlist(spa, spa->spa_config_object, config, tx);
2861 }
2862 
2863 static void
2864 spa_sync_props(void *arg1, void *arg2, dmu_tx_t *tx)
2865 {
2866 	spa_t *spa = arg1;
2867 	nvlist_t *nvp = arg2;
2868 	nvpair_t *nvpair;
2869 	objset_t *mos = spa->spa_meta_objset;
2870 	uint64_t zapobj;
2871 
2872 	mutex_enter(&spa->spa_props_lock);
2873 	if (spa->spa_pool_props_object == 0) {
2874 		zapobj = zap_create(mos, DMU_OT_POOL_PROPS, DMU_OT_NONE, 0, tx);
2875 		VERIFY(zapobj > 0);
2876 
2877 		spa->spa_pool_props_object = zapobj;
2878 
2879 		VERIFY(zap_update(mos, DMU_POOL_DIRECTORY_OBJECT,
2880 		    DMU_POOL_PROPS, 8, 1,
2881 		    &spa->spa_pool_props_object, tx) == 0);
2882 	}
2883 	mutex_exit(&spa->spa_props_lock);
2884 
2885 	nvpair = NULL;
2886 	while ((nvpair = nvlist_next_nvpair(nvp, nvpair))) {
2887 		switch (zpool_name_to_prop(nvpair_name(nvpair))) {
2888 		case ZFS_PROP_BOOTFS:
2889 			VERIFY(nvlist_lookup_uint64(nvp,
2890 			    nvpair_name(nvpair), &spa->spa_bootfs) == 0);
2891 			VERIFY(zap_update(mos,
2892 			    spa->spa_pool_props_object,
2893 			    zpool_prop_to_name(ZFS_PROP_BOOTFS), 8, 1,
2894 			    &spa->spa_bootfs, tx) == 0);
2895 			break;
2896 		}
2897 	}
2898 }
2899 
2900 /*
2901  * Sync the specified transaction group.  New blocks may be dirtied as
2902  * part of the process, so we iterate until it converges.
2903  */
2904 void
2905 spa_sync(spa_t *spa, uint64_t txg)
2906 {
2907 	dsl_pool_t *dp = spa->spa_dsl_pool;
2908 	objset_t *mos = spa->spa_meta_objset;
2909 	bplist_t *bpl = &spa->spa_sync_bplist;
2910 	vdev_t *rvd = spa->spa_root_vdev;
2911 	vdev_t *vd;
2912 	dmu_tx_t *tx;
2913 	int dirty_vdevs;
2914 
2915 	/*
2916 	 * Lock out configuration changes.
2917 	 */
2918 	spa_config_enter(spa, RW_READER, FTAG);
2919 
2920 	spa->spa_syncing_txg = txg;
2921 	spa->spa_sync_pass = 0;
2922 
2923 	VERIFY(0 == bplist_open(bpl, mos, spa->spa_sync_bplist_obj));
2924 
2925 	tx = dmu_tx_create_assigned(dp, txg);
2926 
2927 	/*
2928 	 * If we are upgrading to ZFS_VERSION_RAIDZ_DEFLATE this txg,
2929 	 * set spa_deflate if we have no raid-z vdevs.
2930 	 */
2931 	if (spa->spa_ubsync.ub_version < ZFS_VERSION_RAIDZ_DEFLATE &&
2932 	    spa->spa_uberblock.ub_version >= ZFS_VERSION_RAIDZ_DEFLATE) {
2933 		int i;
2934 
2935 		for (i = 0; i < rvd->vdev_children; i++) {
2936 			vd = rvd->vdev_child[i];
2937 			if (vd->vdev_deflate_ratio != SPA_MINBLOCKSIZE)
2938 				break;
2939 		}
2940 		if (i == rvd->vdev_children) {
2941 			spa->spa_deflate = TRUE;
2942 			VERIFY(0 == zap_add(spa->spa_meta_objset,
2943 			    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_DEFLATE,
2944 			    sizeof (uint64_t), 1, &spa->spa_deflate, tx));
2945 		}
2946 	}
2947 
2948 	/*
2949 	 * If anything has changed in this txg, push the deferred frees
2950 	 * from the previous txg.  If not, leave them alone so that we
2951 	 * don't generate work on an otherwise idle system.
2952 	 */
2953 	if (!txg_list_empty(&dp->dp_dirty_datasets, txg) ||
2954 	    !txg_list_empty(&dp->dp_dirty_dirs, txg) ||
2955 	    !txg_list_empty(&dp->dp_sync_tasks, txg))
2956 		spa_sync_deferred_frees(spa, txg);
2957 
2958 	/*
2959 	 * Iterate to convergence.
2960 	 */
2961 	do {
2962 		spa->spa_sync_pass++;
2963 
2964 		spa_sync_config_object(spa, tx);
2965 		spa_sync_spares(spa, tx);
2966 		spa_errlog_sync(spa, txg);
2967 		dsl_pool_sync(dp, txg);
2968 
2969 		dirty_vdevs = 0;
2970 		while (vd = txg_list_remove(&spa->spa_vdev_txg_list, txg)) {
2971 			vdev_sync(vd, txg);
2972 			dirty_vdevs++;
2973 		}
2974 
2975 		bplist_sync(bpl, tx);
2976 	} while (dirty_vdevs);
2977 
2978 	bplist_close(bpl);
2979 
2980 	dprintf("txg %llu passes %d\n", txg, spa->spa_sync_pass);
2981 
2982 	/*
2983 	 * Rewrite the vdev configuration (which includes the uberblock)
2984 	 * to commit the transaction group.
2985 	 *
2986 	 * If there are any dirty vdevs, sync the uberblock to all vdevs.
2987 	 * Otherwise, pick a random top-level vdev that's known to be
2988 	 * visible in the config cache (see spa_vdev_add() for details).
2989 	 * If the write fails, try the next vdev until we're tried them all.
2990 	 */
2991 	if (!list_is_empty(&spa->spa_dirty_list)) {
2992 		VERIFY(vdev_config_sync(rvd, txg) == 0);
2993 	} else {
2994 		int children = rvd->vdev_children;
2995 		int c0 = spa_get_random(children);
2996 		int c;
2997 
2998 		for (c = 0; c < children; c++) {
2999 			vd = rvd->vdev_child[(c0 + c) % children];
3000 			if (vd->vdev_ms_array == 0)
3001 				continue;
3002 			if (vdev_config_sync(vd, txg) == 0)
3003 				break;
3004 		}
3005 		if (c == children)
3006 			VERIFY(vdev_config_sync(rvd, txg) == 0);
3007 	}
3008 
3009 	dmu_tx_commit(tx);
3010 
3011 	/*
3012 	 * Clear the dirty config list.
3013 	 */
3014 	while ((vd = list_head(&spa->spa_dirty_list)) != NULL)
3015 		vdev_config_clean(vd);
3016 
3017 	/*
3018 	 * Now that the new config has synced transactionally,
3019 	 * let it become visible to the config cache.
3020 	 */
3021 	if (spa->spa_config_syncing != NULL) {
3022 		spa_config_set(spa, spa->spa_config_syncing);
3023 		spa->spa_config_txg = txg;
3024 		spa->spa_config_syncing = NULL;
3025 	}
3026 
3027 	/*
3028 	 * Make a stable copy of the fully synced uberblock.
3029 	 * We use this as the root for pool traversals.
3030 	 */
3031 	spa->spa_traverse_wanted = 1;	/* tells traverse_more() to stop */
3032 
3033 	spa_scrub_suspend(spa);		/* stop scrubbing and finish I/Os */
3034 
3035 	rw_enter(&spa->spa_traverse_lock, RW_WRITER);
3036 	spa->spa_traverse_wanted = 0;
3037 	spa->spa_ubsync = spa->spa_uberblock;
3038 	rw_exit(&spa->spa_traverse_lock);
3039 
3040 	spa_scrub_resume(spa);		/* resume scrub with new ubsync */
3041 
3042 	/*
3043 	 * Clean up the ZIL records for the synced txg.
3044 	 */
3045 	dsl_pool_zil_clean(dp);
3046 
3047 	/*
3048 	 * Update usable space statistics.
3049 	 */
3050 	while (vd = txg_list_remove(&spa->spa_vdev_txg_list, TXG_CLEAN(txg)))
3051 		vdev_sync_done(vd, txg);
3052 
3053 	/*
3054 	 * It had better be the case that we didn't dirty anything
3055 	 * since vdev_config_sync().
3056 	 */
3057 	ASSERT(txg_list_empty(&dp->dp_dirty_datasets, txg));
3058 	ASSERT(txg_list_empty(&dp->dp_dirty_dirs, txg));
3059 	ASSERT(txg_list_empty(&spa->spa_vdev_txg_list, txg));
3060 	ASSERT(bpl->bpl_queue == NULL);
3061 
3062 	spa_config_exit(spa, FTAG);
3063 
3064 	/*
3065 	 * If any async tasks have been requested, kick them off.
3066 	 */
3067 	spa_async_dispatch(spa);
3068 }
3069 
3070 /*
3071  * Sync all pools.  We don't want to hold the namespace lock across these
3072  * operations, so we take a reference on the spa_t and drop the lock during the
3073  * sync.
3074  */
3075 void
3076 spa_sync_allpools(void)
3077 {
3078 	spa_t *spa = NULL;
3079 	mutex_enter(&spa_namespace_lock);
3080 	while ((spa = spa_next(spa)) != NULL) {
3081 		if (spa_state(spa) != POOL_STATE_ACTIVE)
3082 			continue;
3083 		spa_open_ref(spa, FTAG);
3084 		mutex_exit(&spa_namespace_lock);
3085 		txg_wait_synced(spa_get_dsl(spa), 0);
3086 		mutex_enter(&spa_namespace_lock);
3087 		spa_close(spa, FTAG);
3088 	}
3089 	mutex_exit(&spa_namespace_lock);
3090 }
3091 
3092 /*
3093  * ==========================================================================
3094  * Miscellaneous routines
3095  * ==========================================================================
3096  */
3097 
3098 /*
3099  * Remove all pools in the system.
3100  */
3101 void
3102 spa_evict_all(void)
3103 {
3104 	spa_t *spa;
3105 
3106 	/*
3107 	 * Remove all cached state.  All pools should be closed now,
3108 	 * so every spa in the AVL tree should be unreferenced.
3109 	 */
3110 	mutex_enter(&spa_namespace_lock);
3111 	while ((spa = spa_next(NULL)) != NULL) {
3112 		/*
3113 		 * Stop async tasks.  The async thread may need to detach
3114 		 * a device that's been replaced, which requires grabbing
3115 		 * spa_namespace_lock, so we must drop it here.
3116 		 */
3117 		spa_open_ref(spa, FTAG);
3118 		mutex_exit(&spa_namespace_lock);
3119 		spa_async_suspend(spa);
3120 		VERIFY(spa_scrub(spa, POOL_SCRUB_NONE, B_TRUE) == 0);
3121 		mutex_enter(&spa_namespace_lock);
3122 		spa_close(spa, FTAG);
3123 
3124 		if (spa->spa_state != POOL_STATE_UNINITIALIZED) {
3125 			spa_unload(spa);
3126 			spa_deactivate(spa);
3127 		}
3128 		spa_remove(spa);
3129 	}
3130 	mutex_exit(&spa_namespace_lock);
3131 }
3132 
3133 vdev_t *
3134 spa_lookup_by_guid(spa_t *spa, uint64_t guid)
3135 {
3136 	return (vdev_lookup_by_guid(spa->spa_root_vdev, guid));
3137 }
3138 
3139 void
3140 spa_upgrade(spa_t *spa)
3141 {
3142 	spa_config_enter(spa, RW_WRITER, FTAG);
3143 
3144 	/*
3145 	 * This should only be called for a non-faulted pool, and since a
3146 	 * future version would result in an unopenable pool, this shouldn't be
3147 	 * possible.
3148 	 */
3149 	ASSERT(spa->spa_uberblock.ub_version <= ZFS_VERSION);
3150 
3151 	spa->spa_uberblock.ub_version = ZFS_VERSION;
3152 	vdev_config_dirty(spa->spa_root_vdev);
3153 
3154 	spa_config_exit(spa, FTAG);
3155 
3156 	txg_wait_synced(spa_get_dsl(spa), 0);
3157 }
3158 
3159 boolean_t
3160 spa_has_spare(spa_t *spa, uint64_t guid)
3161 {
3162 	int i;
3163 	uint64_t spareguid;
3164 
3165 	for (i = 0; i < spa->spa_nspares; i++)
3166 		if (spa->spa_spares[i]->vdev_guid == guid)
3167 			return (B_TRUE);
3168 
3169 	for (i = 0; i < spa->spa_pending_nspares; i++) {
3170 		if (nvlist_lookup_uint64(spa->spa_pending_spares[i],
3171 		    ZPOOL_CONFIG_GUID, &spareguid) == 0 &&
3172 		    spareguid == guid)
3173 			return (B_TRUE);
3174 	}
3175 
3176 	return (B_FALSE);
3177 }
3178 
3179 int
3180 spa_set_props(spa_t *spa, nvlist_t *nvp)
3181 {
3182 	return (dsl_sync_task_do(spa_get_dsl(spa), NULL, spa_sync_props,
3183 	    spa, nvp, 3));
3184 }
3185 
3186 int
3187 spa_get_props(spa_t *spa, nvlist_t **nvp)
3188 {
3189 	zap_cursor_t zc;
3190 	zap_attribute_t za;
3191 	objset_t *mos = spa->spa_meta_objset;
3192 	zfs_source_t src;
3193 	zfs_prop_t prop;
3194 	nvlist_t *propval;
3195 	uint64_t value;
3196 	int err;
3197 
3198 	VERIFY(nvlist_alloc(nvp, NV_UNIQUE_NAME, KM_SLEEP) == 0);
3199 
3200 	mutex_enter(&spa->spa_props_lock);
3201 	/* If no props object, then just return empty nvlist */
3202 	if (spa->spa_pool_props_object == 0) {
3203 		mutex_exit(&spa->spa_props_lock);
3204 		return (0);
3205 	}
3206 
3207 	for (zap_cursor_init(&zc, mos, spa->spa_pool_props_object);
3208 	    (err = zap_cursor_retrieve(&zc, &za)) == 0;
3209 	    zap_cursor_advance(&zc)) {
3210 
3211 		if ((prop = zpool_name_to_prop(za.za_name)) == ZFS_PROP_INVAL)
3212 			continue;
3213 
3214 		VERIFY(nvlist_alloc(&propval, NV_UNIQUE_NAME, KM_SLEEP) == 0);
3215 		switch (za.za_integer_length) {
3216 		case 8:
3217 			if (zfs_prop_default_numeric(prop) ==
3218 			    za.za_first_integer)
3219 				src = ZFS_SRC_DEFAULT;
3220 			else
3221 				src = ZFS_SRC_LOCAL;
3222 			value = za.za_first_integer;
3223 
3224 			if (prop == ZFS_PROP_BOOTFS) {
3225 				dsl_pool_t *dp;
3226 				dsl_dataset_t *ds = NULL;
3227 				char strval[MAXPATHLEN];
3228 
3229 				dp = spa_get_dsl(spa);
3230 				rw_enter(&dp->dp_config_rwlock, RW_READER);
3231 				if ((err = dsl_dataset_open_obj(dp,
3232 				    za.za_first_integer, NULL, DS_MODE_NONE,
3233 				    FTAG, &ds)) != 0) {
3234 					rw_exit(&dp->dp_config_rwlock);
3235 					break;
3236 				}
3237 				dsl_dataset_name(ds, strval);
3238 				dsl_dataset_close(ds, DS_MODE_NONE, FTAG);
3239 				rw_exit(&dp->dp_config_rwlock);
3240 
3241 				VERIFY(nvlist_add_uint64(propval,
3242 				    ZFS_PROP_SOURCE, src) == 0);
3243 				VERIFY(nvlist_add_string(propval,
3244 				    ZFS_PROP_VALUE, strval) == 0);
3245 			} else {
3246 				VERIFY(nvlist_add_uint64(propval,
3247 				    ZFS_PROP_SOURCE, src) == 0);
3248 				VERIFY(nvlist_add_uint64(propval,
3249 				    ZFS_PROP_VALUE, value) == 0);
3250 			}
3251 			VERIFY(nvlist_add_nvlist(*nvp, za.za_name,
3252 			    propval) == 0);
3253 			break;
3254 		}
3255 		nvlist_free(propval);
3256 	}
3257 	zap_cursor_fini(&zc);
3258 	mutex_exit(&spa->spa_props_lock);
3259 	if (err && err != ENOENT) {
3260 		nvlist_free(*nvp);
3261 		return (err);
3262 	}
3263 
3264 	return (0);
3265 }
3266 
3267 /*
3268  * If the bootfs property value is dsobj, clear it.
3269  */
3270 void
3271 spa_clear_bootfs(spa_t *spa, uint64_t dsobj, dmu_tx_t *tx)
3272 {
3273 	if (spa->spa_bootfs == dsobj && spa->spa_pool_props_object != 0) {
3274 		VERIFY(zap_remove(spa->spa_meta_objset,
3275 		    spa->spa_pool_props_object,
3276 		    zpool_prop_to_name(ZFS_PROP_BOOTFS), tx) == 0);
3277 		spa->spa_bootfs = 0;
3278 	}
3279 }
3280