xref: /freebsd/sys/contrib/openzfs/module/zfs/spa.c (revision c66ec88fed842fbaad62c30d510644ceb7bd2d71)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
24  * Copyright (c) 2011, 2020 by Delphix. All rights reserved.
25  * Copyright (c) 2018, Nexenta Systems, Inc.  All rights reserved.
26  * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
27  * Copyright 2013 Saso Kiselkov. All rights reserved.
28  * Copyright (c) 2014 Integros [integros.com]
29  * Copyright 2016 Toomas Soome <tsoome@me.com>
30  * Copyright (c) 2016 Actifio, Inc. All rights reserved.
31  * Copyright 2018 Joyent, Inc.
32  * Copyright (c) 2017, 2019, Datto Inc. All rights reserved.
33  * Copyright 2017 Joyent, Inc.
34  * Copyright (c) 2017, Intel Corporation.
35  */
36 
37 /*
38  * SPA: Storage Pool Allocator
39  *
40  * This file contains all the routines used when modifying on-disk SPA state.
41  * This includes opening, importing, destroying, exporting a pool, and syncing a
42  * pool.
43  */
44 
45 #include <sys/zfs_context.h>
46 #include <sys/fm/fs/zfs.h>
47 #include <sys/spa_impl.h>
48 #include <sys/zio.h>
49 #include <sys/zio_checksum.h>
50 #include <sys/dmu.h>
51 #include <sys/dmu_tx.h>
52 #include <sys/zap.h>
53 #include <sys/zil.h>
54 #include <sys/ddt.h>
55 #include <sys/vdev_impl.h>
56 #include <sys/vdev_removal.h>
57 #include <sys/vdev_indirect_mapping.h>
58 #include <sys/vdev_indirect_births.h>
59 #include <sys/vdev_initialize.h>
60 #include <sys/vdev_rebuild.h>
61 #include <sys/vdev_trim.h>
62 #include <sys/vdev_disk.h>
63 #include <sys/vdev_draid.h>
64 #include <sys/metaslab.h>
65 #include <sys/metaslab_impl.h>
66 #include <sys/mmp.h>
67 #include <sys/uberblock_impl.h>
68 #include <sys/txg.h>
69 #include <sys/avl.h>
70 #include <sys/bpobj.h>
71 #include <sys/dmu_traverse.h>
72 #include <sys/dmu_objset.h>
73 #include <sys/unique.h>
74 #include <sys/dsl_pool.h>
75 #include <sys/dsl_dataset.h>
76 #include <sys/dsl_dir.h>
77 #include <sys/dsl_prop.h>
78 #include <sys/dsl_synctask.h>
79 #include <sys/fs/zfs.h>
80 #include <sys/arc.h>
81 #include <sys/callb.h>
82 #include <sys/systeminfo.h>
83 #include <sys/spa_boot.h>
84 #include <sys/zfs_ioctl.h>
85 #include <sys/dsl_scan.h>
86 #include <sys/zfeature.h>
87 #include <sys/dsl_destroy.h>
88 #include <sys/zvol.h>
89 
90 #ifdef	_KERNEL
91 #include <sys/fm/protocol.h>
92 #include <sys/fm/util.h>
93 #include <sys/callb.h>
94 #include <sys/zone.h>
95 #include <sys/vmsystm.h>
96 #endif	/* _KERNEL */
97 
98 #include "zfs_prop.h"
99 #include "zfs_comutil.h"
100 
101 /*
102  * The interval, in seconds, at which failed configuration cache file writes
103  * should be retried.
104  */
105 int zfs_ccw_retry_interval = 300;
106 
107 typedef enum zti_modes {
108 	ZTI_MODE_FIXED,			/* value is # of threads (min 1) */
109 	ZTI_MODE_BATCH,			/* cpu-intensive; value is ignored */
110 	ZTI_MODE_NULL,			/* don't create a taskq */
111 	ZTI_NMODES
112 } zti_modes_t;
113 
114 #define	ZTI_P(n, q)	{ ZTI_MODE_FIXED, (n), (q) }
115 #define	ZTI_PCT(n)	{ ZTI_MODE_ONLINE_PERCENT, (n), 1 }
116 #define	ZTI_BATCH	{ ZTI_MODE_BATCH, 0, 1 }
117 #define	ZTI_NULL	{ ZTI_MODE_NULL, 0, 0 }
118 
119 #define	ZTI_N(n)	ZTI_P(n, 1)
120 #define	ZTI_ONE		ZTI_N(1)
121 
122 typedef struct zio_taskq_info {
123 	zti_modes_t zti_mode;
124 	uint_t zti_value;
125 	uint_t zti_count;
126 } zio_taskq_info_t;
127 
128 static const char *const zio_taskq_types[ZIO_TASKQ_TYPES] = {
129 	"iss", "iss_h", "int", "int_h"
130 };
131 
132 /*
133  * This table defines the taskq settings for each ZFS I/O type. When
134  * initializing a pool, we use this table to create an appropriately sized
135  * taskq. Some operations are low volume and therefore have a small, static
136  * number of threads assigned to their taskqs using the ZTI_N(#) or ZTI_ONE
137  * macros. Other operations process a large amount of data; the ZTI_BATCH
138  * macro causes us to create a taskq oriented for throughput. Some operations
139  * are so high frequency and short-lived that the taskq itself can become a
140  * point of lock contention. The ZTI_P(#, #) macro indicates that we need an
141  * additional degree of parallelism specified by the number of threads per-
142  * taskq and the number of taskqs; when dispatching an event in this case, the
143  * particular taskq is chosen at random.
144  *
145  * The different taskq priorities are to handle the different contexts (issue
146  * and interrupt) and then to reserve threads for ZIO_PRIORITY_NOW I/Os that
147  * need to be handled with minimum delay.
148  */
149 const zio_taskq_info_t zio_taskqs[ZIO_TYPES][ZIO_TASKQ_TYPES] = {
150 	/* ISSUE	ISSUE_HIGH	INTR		INTR_HIGH */
151 	{ ZTI_ONE,	ZTI_NULL,	ZTI_ONE,	ZTI_NULL }, /* NULL */
152 	{ ZTI_N(8),	ZTI_NULL,	ZTI_P(12, 8),	ZTI_NULL }, /* READ */
153 	{ ZTI_BATCH,	ZTI_N(5),	ZTI_P(12, 8),	ZTI_N(5) }, /* WRITE */
154 	{ ZTI_P(12, 8),	ZTI_NULL,	ZTI_ONE,	ZTI_NULL }, /* FREE */
155 	{ ZTI_ONE,	ZTI_NULL,	ZTI_ONE,	ZTI_NULL }, /* CLAIM */
156 	{ ZTI_ONE,	ZTI_NULL,	ZTI_ONE,	ZTI_NULL }, /* IOCTL */
157 	{ ZTI_N(4),	ZTI_NULL,	ZTI_ONE,	ZTI_NULL }, /* TRIM */
158 };
159 
160 static void spa_sync_version(void *arg, dmu_tx_t *tx);
161 static void spa_sync_props(void *arg, dmu_tx_t *tx);
162 static boolean_t spa_has_active_shared_spare(spa_t *spa);
163 static int spa_load_impl(spa_t *spa, spa_import_type_t type, char **ereport);
164 static void spa_vdev_resilver_done(spa_t *spa);
165 
166 uint_t		zio_taskq_batch_pct = 75;	/* 1 thread per cpu in pset */
167 boolean_t	zio_taskq_sysdc = B_TRUE;	/* use SDC scheduling class */
168 uint_t		zio_taskq_basedc = 80;		/* base duty cycle */
169 
170 boolean_t	spa_create_process = B_TRUE;	/* no process ==> no sysdc */
171 
172 /*
173  * Report any spa_load_verify errors found, but do not fail spa_load.
174  * This is used by zdb to analyze non-idle pools.
175  */
176 boolean_t	spa_load_verify_dryrun = B_FALSE;
177 
178 /*
179  * This (illegal) pool name is used when temporarily importing a spa_t in order
180  * to get the vdev stats associated with the imported devices.
181  */
182 #define	TRYIMPORT_NAME	"$import"
183 
184 /*
185  * For debugging purposes: print out vdev tree during pool import.
186  */
187 int		spa_load_print_vdev_tree = B_FALSE;
188 
189 /*
190  * A non-zero value for zfs_max_missing_tvds means that we allow importing
191  * pools with missing top-level vdevs. This is strictly intended for advanced
192  * pool recovery cases since missing data is almost inevitable. Pools with
193  * missing devices can only be imported read-only for safety reasons, and their
194  * fail-mode will be automatically set to "continue".
195  *
196  * With 1 missing vdev we should be able to import the pool and mount all
197  * datasets. User data that was not modified after the missing device has been
198  * added should be recoverable. This means that snapshots created prior to the
199  * addition of that device should be completely intact.
200  *
201  * With 2 missing vdevs, some datasets may fail to mount since there are
202  * dataset statistics that are stored as regular metadata. Some data might be
203  * recoverable if those vdevs were added recently.
204  *
205  * With 3 or more missing vdevs, the pool is severely damaged and MOS entries
206  * may be missing entirely. Chances of data recovery are very low. Note that
207  * there are also risks of performing an inadvertent rewind as we might be
208  * missing all the vdevs with the latest uberblocks.
209  */
210 unsigned long	zfs_max_missing_tvds = 0;
211 
212 /*
213  * The parameters below are similar to zfs_max_missing_tvds but are only
214  * intended for a preliminary open of the pool with an untrusted config which
215  * might be incomplete or out-dated.
216  *
217  * We are more tolerant for pools opened from a cachefile since we could have
218  * an out-dated cachefile where a device removal was not registered.
219  * We could have set the limit arbitrarily high but in the case where devices
220  * are really missing we would want to return the proper error codes; we chose
221  * SPA_DVAS_PER_BP - 1 so that some copies of the MOS would still be available
222  * and we get a chance to retrieve the trusted config.
223  */
224 uint64_t	zfs_max_missing_tvds_cachefile = SPA_DVAS_PER_BP - 1;
225 
226 /*
227  * In the case where config was assembled by scanning device paths (/dev/dsks
228  * by default) we are less tolerant since all the existing devices should have
229  * been detected and we want spa_load to return the right error codes.
230  */
231 uint64_t	zfs_max_missing_tvds_scan = 0;
232 
233 /*
234  * Debugging aid that pauses spa_sync() towards the end.
235  */
236 boolean_t	zfs_pause_spa_sync = B_FALSE;
237 
238 /*
239  * Variables to indicate the livelist condense zthr func should wait at certain
240  * points for the livelist to be removed - used to test condense/destroy races
241  */
242 int zfs_livelist_condense_zthr_pause = 0;
243 int zfs_livelist_condense_sync_pause = 0;
244 
245 /*
246  * Variables to track whether or not condense cancellation has been
247  * triggered in testing.
248  */
249 int zfs_livelist_condense_sync_cancel = 0;
250 int zfs_livelist_condense_zthr_cancel = 0;
251 
252 /*
253  * Variable to track whether or not extra ALLOC blkptrs were added to a
254  * livelist entry while it was being condensed (caused by the way we track
255  * remapped blkptrs in dbuf_remap_impl)
256  */
257 int zfs_livelist_condense_new_alloc = 0;
258 
259 /*
260  * ==========================================================================
261  * SPA properties routines
262  * ==========================================================================
263  */
264 
265 /*
266  * Add a (source=src, propname=propval) list to an nvlist.
267  */
268 static void
269 spa_prop_add_list(nvlist_t *nvl, zpool_prop_t prop, char *strval,
270     uint64_t intval, zprop_source_t src)
271 {
272 	const char *propname = zpool_prop_to_name(prop);
273 	nvlist_t *propval;
274 
275 	VERIFY(nvlist_alloc(&propval, NV_UNIQUE_NAME, KM_SLEEP) == 0);
276 	VERIFY(nvlist_add_uint64(propval, ZPROP_SOURCE, src) == 0);
277 
278 	if (strval != NULL)
279 		VERIFY(nvlist_add_string(propval, ZPROP_VALUE, strval) == 0);
280 	else
281 		VERIFY(nvlist_add_uint64(propval, ZPROP_VALUE, intval) == 0);
282 
283 	VERIFY(nvlist_add_nvlist(nvl, propname, propval) == 0);
284 	nvlist_free(propval);
285 }
286 
287 /*
288  * Get property values from the spa configuration.
289  */
290 static void
291 spa_prop_get_config(spa_t *spa, nvlist_t **nvp)
292 {
293 	vdev_t *rvd = spa->spa_root_vdev;
294 	dsl_pool_t *pool = spa->spa_dsl_pool;
295 	uint64_t size, alloc, cap, version;
296 	const zprop_source_t src = ZPROP_SRC_NONE;
297 	spa_config_dirent_t *dp;
298 	metaslab_class_t *mc = spa_normal_class(spa);
299 
300 	ASSERT(MUTEX_HELD(&spa->spa_props_lock));
301 
302 	if (rvd != NULL) {
303 		alloc = metaslab_class_get_alloc(mc);
304 		alloc += metaslab_class_get_alloc(spa_special_class(spa));
305 		alloc += metaslab_class_get_alloc(spa_dedup_class(spa));
306 
307 		size = metaslab_class_get_space(mc);
308 		size += metaslab_class_get_space(spa_special_class(spa));
309 		size += metaslab_class_get_space(spa_dedup_class(spa));
310 
311 		spa_prop_add_list(*nvp, ZPOOL_PROP_NAME, spa_name(spa), 0, src);
312 		spa_prop_add_list(*nvp, ZPOOL_PROP_SIZE, NULL, size, src);
313 		spa_prop_add_list(*nvp, ZPOOL_PROP_ALLOCATED, NULL, alloc, src);
314 		spa_prop_add_list(*nvp, ZPOOL_PROP_FREE, NULL,
315 		    size - alloc, src);
316 		spa_prop_add_list(*nvp, ZPOOL_PROP_CHECKPOINT, NULL,
317 		    spa->spa_checkpoint_info.sci_dspace, src);
318 
319 		spa_prop_add_list(*nvp, ZPOOL_PROP_FRAGMENTATION, NULL,
320 		    metaslab_class_fragmentation(mc), src);
321 		spa_prop_add_list(*nvp, ZPOOL_PROP_EXPANDSZ, NULL,
322 		    metaslab_class_expandable_space(mc), src);
323 		spa_prop_add_list(*nvp, ZPOOL_PROP_READONLY, NULL,
324 		    (spa_mode(spa) == SPA_MODE_READ), src);
325 
326 		cap = (size == 0) ? 0 : (alloc * 100 / size);
327 		spa_prop_add_list(*nvp, ZPOOL_PROP_CAPACITY, NULL, cap, src);
328 
329 		spa_prop_add_list(*nvp, ZPOOL_PROP_DEDUPRATIO, NULL,
330 		    ddt_get_pool_dedup_ratio(spa), src);
331 
332 		spa_prop_add_list(*nvp, ZPOOL_PROP_HEALTH, NULL,
333 		    rvd->vdev_state, src);
334 
335 		version = spa_version(spa);
336 		if (version == zpool_prop_default_numeric(ZPOOL_PROP_VERSION)) {
337 			spa_prop_add_list(*nvp, ZPOOL_PROP_VERSION, NULL,
338 			    version, ZPROP_SRC_DEFAULT);
339 		} else {
340 			spa_prop_add_list(*nvp, ZPOOL_PROP_VERSION, NULL,
341 			    version, ZPROP_SRC_LOCAL);
342 		}
343 		spa_prop_add_list(*nvp, ZPOOL_PROP_LOAD_GUID,
344 		    NULL, spa_load_guid(spa), src);
345 	}
346 
347 	if (pool != NULL) {
348 		/*
349 		 * The $FREE directory was introduced in SPA_VERSION_DEADLISTS,
350 		 * when opening pools before this version freedir will be NULL.
351 		 */
352 		if (pool->dp_free_dir != NULL) {
353 			spa_prop_add_list(*nvp, ZPOOL_PROP_FREEING, NULL,
354 			    dsl_dir_phys(pool->dp_free_dir)->dd_used_bytes,
355 			    src);
356 		} else {
357 			spa_prop_add_list(*nvp, ZPOOL_PROP_FREEING,
358 			    NULL, 0, src);
359 		}
360 
361 		if (pool->dp_leak_dir != NULL) {
362 			spa_prop_add_list(*nvp, ZPOOL_PROP_LEAKED, NULL,
363 			    dsl_dir_phys(pool->dp_leak_dir)->dd_used_bytes,
364 			    src);
365 		} else {
366 			spa_prop_add_list(*nvp, ZPOOL_PROP_LEAKED,
367 			    NULL, 0, src);
368 		}
369 	}
370 
371 	spa_prop_add_list(*nvp, ZPOOL_PROP_GUID, NULL, spa_guid(spa), src);
372 
373 	if (spa->spa_comment != NULL) {
374 		spa_prop_add_list(*nvp, ZPOOL_PROP_COMMENT, spa->spa_comment,
375 		    0, ZPROP_SRC_LOCAL);
376 	}
377 
378 	if (spa->spa_root != NULL)
379 		spa_prop_add_list(*nvp, ZPOOL_PROP_ALTROOT, spa->spa_root,
380 		    0, ZPROP_SRC_LOCAL);
381 
382 	if (spa_feature_is_enabled(spa, SPA_FEATURE_LARGE_BLOCKS)) {
383 		spa_prop_add_list(*nvp, ZPOOL_PROP_MAXBLOCKSIZE, NULL,
384 		    MIN(zfs_max_recordsize, SPA_MAXBLOCKSIZE), ZPROP_SRC_NONE);
385 	} else {
386 		spa_prop_add_list(*nvp, ZPOOL_PROP_MAXBLOCKSIZE, NULL,
387 		    SPA_OLD_MAXBLOCKSIZE, ZPROP_SRC_NONE);
388 	}
389 
390 	if (spa_feature_is_enabled(spa, SPA_FEATURE_LARGE_DNODE)) {
391 		spa_prop_add_list(*nvp, ZPOOL_PROP_MAXDNODESIZE, NULL,
392 		    DNODE_MAX_SIZE, ZPROP_SRC_NONE);
393 	} else {
394 		spa_prop_add_list(*nvp, ZPOOL_PROP_MAXDNODESIZE, NULL,
395 		    DNODE_MIN_SIZE, ZPROP_SRC_NONE);
396 	}
397 
398 	if ((dp = list_head(&spa->spa_config_list)) != NULL) {
399 		if (dp->scd_path == NULL) {
400 			spa_prop_add_list(*nvp, ZPOOL_PROP_CACHEFILE,
401 			    "none", 0, ZPROP_SRC_LOCAL);
402 		} else if (strcmp(dp->scd_path, spa_config_path) != 0) {
403 			spa_prop_add_list(*nvp, ZPOOL_PROP_CACHEFILE,
404 			    dp->scd_path, 0, ZPROP_SRC_LOCAL);
405 		}
406 	}
407 }
408 
409 /*
410  * Get zpool property values.
411  */
412 int
413 spa_prop_get(spa_t *spa, nvlist_t **nvp)
414 {
415 	objset_t *mos = spa->spa_meta_objset;
416 	zap_cursor_t zc;
417 	zap_attribute_t za;
418 	dsl_pool_t *dp;
419 	int err;
420 
421 	err = nvlist_alloc(nvp, NV_UNIQUE_NAME, KM_SLEEP);
422 	if (err)
423 		return (err);
424 
425 	dp = spa_get_dsl(spa);
426 	dsl_pool_config_enter(dp, FTAG);
427 	mutex_enter(&spa->spa_props_lock);
428 
429 	/*
430 	 * Get properties from the spa config.
431 	 */
432 	spa_prop_get_config(spa, nvp);
433 
434 	/* If no pool property object, no more prop to get. */
435 	if (mos == NULL || spa->spa_pool_props_object == 0)
436 		goto out;
437 
438 	/*
439 	 * Get properties from the MOS pool property object.
440 	 */
441 	for (zap_cursor_init(&zc, mos, spa->spa_pool_props_object);
442 	    (err = zap_cursor_retrieve(&zc, &za)) == 0;
443 	    zap_cursor_advance(&zc)) {
444 		uint64_t intval = 0;
445 		char *strval = NULL;
446 		zprop_source_t src = ZPROP_SRC_DEFAULT;
447 		zpool_prop_t prop;
448 
449 		if ((prop = zpool_name_to_prop(za.za_name)) == ZPOOL_PROP_INVAL)
450 			continue;
451 
452 		switch (za.za_integer_length) {
453 		case 8:
454 			/* integer property */
455 			if (za.za_first_integer !=
456 			    zpool_prop_default_numeric(prop))
457 				src = ZPROP_SRC_LOCAL;
458 
459 			if (prop == ZPOOL_PROP_BOOTFS) {
460 				dsl_dataset_t *ds = NULL;
461 
462 				err = dsl_dataset_hold_obj(dp,
463 				    za.za_first_integer, FTAG, &ds);
464 				if (err != 0)
465 					break;
466 
467 				strval = kmem_alloc(ZFS_MAX_DATASET_NAME_LEN,
468 				    KM_SLEEP);
469 				dsl_dataset_name(ds, strval);
470 				dsl_dataset_rele(ds, FTAG);
471 			} else {
472 				strval = NULL;
473 				intval = za.za_first_integer;
474 			}
475 
476 			spa_prop_add_list(*nvp, prop, strval, intval, src);
477 
478 			if (strval != NULL)
479 				kmem_free(strval, ZFS_MAX_DATASET_NAME_LEN);
480 
481 			break;
482 
483 		case 1:
484 			/* string property */
485 			strval = kmem_alloc(za.za_num_integers, KM_SLEEP);
486 			err = zap_lookup(mos, spa->spa_pool_props_object,
487 			    za.za_name, 1, za.za_num_integers, strval);
488 			if (err) {
489 				kmem_free(strval, za.za_num_integers);
490 				break;
491 			}
492 			spa_prop_add_list(*nvp, prop, strval, 0, src);
493 			kmem_free(strval, za.za_num_integers);
494 			break;
495 
496 		default:
497 			break;
498 		}
499 	}
500 	zap_cursor_fini(&zc);
501 out:
502 	mutex_exit(&spa->spa_props_lock);
503 	dsl_pool_config_exit(dp, FTAG);
504 	if (err && err != ENOENT) {
505 		nvlist_free(*nvp);
506 		*nvp = NULL;
507 		return (err);
508 	}
509 
510 	return (0);
511 }
512 
513 /*
514  * Validate the given pool properties nvlist and modify the list
515  * for the property values to be set.
516  */
517 static int
518 spa_prop_validate(spa_t *spa, nvlist_t *props)
519 {
520 	nvpair_t *elem;
521 	int error = 0, reset_bootfs = 0;
522 	uint64_t objnum = 0;
523 	boolean_t has_feature = B_FALSE;
524 
525 	elem = NULL;
526 	while ((elem = nvlist_next_nvpair(props, elem)) != NULL) {
527 		uint64_t intval;
528 		char *strval, *slash, *check, *fname;
529 		const char *propname = nvpair_name(elem);
530 		zpool_prop_t prop = zpool_name_to_prop(propname);
531 
532 		switch (prop) {
533 		case ZPOOL_PROP_INVAL:
534 			if (!zpool_prop_feature(propname)) {
535 				error = SET_ERROR(EINVAL);
536 				break;
537 			}
538 
539 			/*
540 			 * Sanitize the input.
541 			 */
542 			if (nvpair_type(elem) != DATA_TYPE_UINT64) {
543 				error = SET_ERROR(EINVAL);
544 				break;
545 			}
546 
547 			if (nvpair_value_uint64(elem, &intval) != 0) {
548 				error = SET_ERROR(EINVAL);
549 				break;
550 			}
551 
552 			if (intval != 0) {
553 				error = SET_ERROR(EINVAL);
554 				break;
555 			}
556 
557 			fname = strchr(propname, '@') + 1;
558 			if (zfeature_lookup_name(fname, NULL) != 0) {
559 				error = SET_ERROR(EINVAL);
560 				break;
561 			}
562 
563 			has_feature = B_TRUE;
564 			break;
565 
566 		case ZPOOL_PROP_VERSION:
567 			error = nvpair_value_uint64(elem, &intval);
568 			if (!error &&
569 			    (intval < spa_version(spa) ||
570 			    intval > SPA_VERSION_BEFORE_FEATURES ||
571 			    has_feature))
572 				error = SET_ERROR(EINVAL);
573 			break;
574 
575 		case ZPOOL_PROP_DELEGATION:
576 		case ZPOOL_PROP_AUTOREPLACE:
577 		case ZPOOL_PROP_LISTSNAPS:
578 		case ZPOOL_PROP_AUTOEXPAND:
579 		case ZPOOL_PROP_AUTOTRIM:
580 			error = nvpair_value_uint64(elem, &intval);
581 			if (!error && intval > 1)
582 				error = SET_ERROR(EINVAL);
583 			break;
584 
585 		case ZPOOL_PROP_MULTIHOST:
586 			error = nvpair_value_uint64(elem, &intval);
587 			if (!error && intval > 1)
588 				error = SET_ERROR(EINVAL);
589 
590 			if (!error) {
591 				uint32_t hostid = zone_get_hostid(NULL);
592 				if (hostid)
593 					spa->spa_hostid = hostid;
594 				else
595 					error = SET_ERROR(ENOTSUP);
596 			}
597 
598 			break;
599 
600 		case ZPOOL_PROP_BOOTFS:
601 			/*
602 			 * If the pool version is less than SPA_VERSION_BOOTFS,
603 			 * or the pool is still being created (version == 0),
604 			 * the bootfs property cannot be set.
605 			 */
606 			if (spa_version(spa) < SPA_VERSION_BOOTFS) {
607 				error = SET_ERROR(ENOTSUP);
608 				break;
609 			}
610 
611 			/*
612 			 * Make sure the vdev config is bootable
613 			 */
614 			if (!vdev_is_bootable(spa->spa_root_vdev)) {
615 				error = SET_ERROR(ENOTSUP);
616 				break;
617 			}
618 
619 			reset_bootfs = 1;
620 
621 			error = nvpair_value_string(elem, &strval);
622 
623 			if (!error) {
624 				objset_t *os;
625 
626 				if (strval == NULL || strval[0] == '\0') {
627 					objnum = zpool_prop_default_numeric(
628 					    ZPOOL_PROP_BOOTFS);
629 					break;
630 				}
631 
632 				error = dmu_objset_hold(strval, FTAG, &os);
633 				if (error != 0)
634 					break;
635 
636 				/* Must be ZPL. */
637 				if (dmu_objset_type(os) != DMU_OST_ZFS) {
638 					error = SET_ERROR(ENOTSUP);
639 				} else {
640 					objnum = dmu_objset_id(os);
641 				}
642 				dmu_objset_rele(os, FTAG);
643 			}
644 			break;
645 
646 		case ZPOOL_PROP_FAILUREMODE:
647 			error = nvpair_value_uint64(elem, &intval);
648 			if (!error && intval > ZIO_FAILURE_MODE_PANIC)
649 				error = SET_ERROR(EINVAL);
650 
651 			/*
652 			 * This is a special case which only occurs when
653 			 * the pool has completely failed. This allows
654 			 * the user to change the in-core failmode property
655 			 * without syncing it out to disk (I/Os might
656 			 * currently be blocked). We do this by returning
657 			 * EIO to the caller (spa_prop_set) to trick it
658 			 * into thinking we encountered a property validation
659 			 * error.
660 			 */
661 			if (!error && spa_suspended(spa)) {
662 				spa->spa_failmode = intval;
663 				error = SET_ERROR(EIO);
664 			}
665 			break;
666 
667 		case ZPOOL_PROP_CACHEFILE:
668 			if ((error = nvpair_value_string(elem, &strval)) != 0)
669 				break;
670 
671 			if (strval[0] == '\0')
672 				break;
673 
674 			if (strcmp(strval, "none") == 0)
675 				break;
676 
677 			if (strval[0] != '/') {
678 				error = SET_ERROR(EINVAL);
679 				break;
680 			}
681 
682 			slash = strrchr(strval, '/');
683 			ASSERT(slash != NULL);
684 
685 			if (slash[1] == '\0' || strcmp(slash, "/.") == 0 ||
686 			    strcmp(slash, "/..") == 0)
687 				error = SET_ERROR(EINVAL);
688 			break;
689 
690 		case ZPOOL_PROP_COMMENT:
691 			if ((error = nvpair_value_string(elem, &strval)) != 0)
692 				break;
693 			for (check = strval; *check != '\0'; check++) {
694 				if (!isprint(*check)) {
695 					error = SET_ERROR(EINVAL);
696 					break;
697 				}
698 			}
699 			if (strlen(strval) > ZPROP_MAX_COMMENT)
700 				error = SET_ERROR(E2BIG);
701 			break;
702 
703 		default:
704 			break;
705 		}
706 
707 		if (error)
708 			break;
709 	}
710 
711 	(void) nvlist_remove_all(props,
712 	    zpool_prop_to_name(ZPOOL_PROP_DEDUPDITTO));
713 
714 	if (!error && reset_bootfs) {
715 		error = nvlist_remove(props,
716 		    zpool_prop_to_name(ZPOOL_PROP_BOOTFS), DATA_TYPE_STRING);
717 
718 		if (!error) {
719 			error = nvlist_add_uint64(props,
720 			    zpool_prop_to_name(ZPOOL_PROP_BOOTFS), objnum);
721 		}
722 	}
723 
724 	return (error);
725 }
726 
727 void
728 spa_configfile_set(spa_t *spa, nvlist_t *nvp, boolean_t need_sync)
729 {
730 	char *cachefile;
731 	spa_config_dirent_t *dp;
732 
733 	if (nvlist_lookup_string(nvp, zpool_prop_to_name(ZPOOL_PROP_CACHEFILE),
734 	    &cachefile) != 0)
735 		return;
736 
737 	dp = kmem_alloc(sizeof (spa_config_dirent_t),
738 	    KM_SLEEP);
739 
740 	if (cachefile[0] == '\0')
741 		dp->scd_path = spa_strdup(spa_config_path);
742 	else if (strcmp(cachefile, "none") == 0)
743 		dp->scd_path = NULL;
744 	else
745 		dp->scd_path = spa_strdup(cachefile);
746 
747 	list_insert_head(&spa->spa_config_list, dp);
748 	if (need_sync)
749 		spa_async_request(spa, SPA_ASYNC_CONFIG_UPDATE);
750 }
751 
752 int
753 spa_prop_set(spa_t *spa, nvlist_t *nvp)
754 {
755 	int error;
756 	nvpair_t *elem = NULL;
757 	boolean_t need_sync = B_FALSE;
758 
759 	if ((error = spa_prop_validate(spa, nvp)) != 0)
760 		return (error);
761 
762 	while ((elem = nvlist_next_nvpair(nvp, elem)) != NULL) {
763 		zpool_prop_t prop = zpool_name_to_prop(nvpair_name(elem));
764 
765 		if (prop == ZPOOL_PROP_CACHEFILE ||
766 		    prop == ZPOOL_PROP_ALTROOT ||
767 		    prop == ZPOOL_PROP_READONLY)
768 			continue;
769 
770 		if (prop == ZPOOL_PROP_VERSION || prop == ZPOOL_PROP_INVAL) {
771 			uint64_t ver;
772 
773 			if (prop == ZPOOL_PROP_VERSION) {
774 				VERIFY(nvpair_value_uint64(elem, &ver) == 0);
775 			} else {
776 				ASSERT(zpool_prop_feature(nvpair_name(elem)));
777 				ver = SPA_VERSION_FEATURES;
778 				need_sync = B_TRUE;
779 			}
780 
781 			/* Save time if the version is already set. */
782 			if (ver == spa_version(spa))
783 				continue;
784 
785 			/*
786 			 * In addition to the pool directory object, we might
787 			 * create the pool properties object, the features for
788 			 * read object, the features for write object, or the
789 			 * feature descriptions object.
790 			 */
791 			error = dsl_sync_task(spa->spa_name, NULL,
792 			    spa_sync_version, &ver,
793 			    6, ZFS_SPACE_CHECK_RESERVED);
794 			if (error)
795 				return (error);
796 			continue;
797 		}
798 
799 		need_sync = B_TRUE;
800 		break;
801 	}
802 
803 	if (need_sync) {
804 		return (dsl_sync_task(spa->spa_name, NULL, spa_sync_props,
805 		    nvp, 6, ZFS_SPACE_CHECK_RESERVED));
806 	}
807 
808 	return (0);
809 }
810 
811 /*
812  * If the bootfs property value is dsobj, clear it.
813  */
814 void
815 spa_prop_clear_bootfs(spa_t *spa, uint64_t dsobj, dmu_tx_t *tx)
816 {
817 	if (spa->spa_bootfs == dsobj && spa->spa_pool_props_object != 0) {
818 		VERIFY(zap_remove(spa->spa_meta_objset,
819 		    spa->spa_pool_props_object,
820 		    zpool_prop_to_name(ZPOOL_PROP_BOOTFS), tx) == 0);
821 		spa->spa_bootfs = 0;
822 	}
823 }
824 
825 /*ARGSUSED*/
826 static int
827 spa_change_guid_check(void *arg, dmu_tx_t *tx)
828 {
829 	uint64_t *newguid __maybe_unused = arg;
830 	spa_t *spa = dmu_tx_pool(tx)->dp_spa;
831 	vdev_t *rvd = spa->spa_root_vdev;
832 	uint64_t vdev_state;
833 
834 	if (spa_feature_is_active(spa, SPA_FEATURE_POOL_CHECKPOINT)) {
835 		int error = (spa_has_checkpoint(spa)) ?
836 		    ZFS_ERR_CHECKPOINT_EXISTS : ZFS_ERR_DISCARDING_CHECKPOINT;
837 		return (SET_ERROR(error));
838 	}
839 
840 	spa_config_enter(spa, SCL_STATE, FTAG, RW_READER);
841 	vdev_state = rvd->vdev_state;
842 	spa_config_exit(spa, SCL_STATE, FTAG);
843 
844 	if (vdev_state != VDEV_STATE_HEALTHY)
845 		return (SET_ERROR(ENXIO));
846 
847 	ASSERT3U(spa_guid(spa), !=, *newguid);
848 
849 	return (0);
850 }
851 
852 static void
853 spa_change_guid_sync(void *arg, dmu_tx_t *tx)
854 {
855 	uint64_t *newguid = arg;
856 	spa_t *spa = dmu_tx_pool(tx)->dp_spa;
857 	uint64_t oldguid;
858 	vdev_t *rvd = spa->spa_root_vdev;
859 
860 	oldguid = spa_guid(spa);
861 
862 	spa_config_enter(spa, SCL_STATE, FTAG, RW_READER);
863 	rvd->vdev_guid = *newguid;
864 	rvd->vdev_guid_sum += (*newguid - oldguid);
865 	vdev_config_dirty(rvd);
866 	spa_config_exit(spa, SCL_STATE, FTAG);
867 
868 	spa_history_log_internal(spa, "guid change", tx, "old=%llu new=%llu",
869 	    (u_longlong_t)oldguid, (u_longlong_t)*newguid);
870 }
871 
872 /*
873  * Change the GUID for the pool.  This is done so that we can later
874  * re-import a pool built from a clone of our own vdevs.  We will modify
875  * the root vdev's guid, our own pool guid, and then mark all of our
876  * vdevs dirty.  Note that we must make sure that all our vdevs are
877  * online when we do this, or else any vdevs that weren't present
878  * would be orphaned from our pool.  We are also going to issue a
879  * sysevent to update any watchers.
880  */
881 int
882 spa_change_guid(spa_t *spa)
883 {
884 	int error;
885 	uint64_t guid;
886 
887 	mutex_enter(&spa->spa_vdev_top_lock);
888 	mutex_enter(&spa_namespace_lock);
889 	guid = spa_generate_guid(NULL);
890 
891 	error = dsl_sync_task(spa->spa_name, spa_change_guid_check,
892 	    spa_change_guid_sync, &guid, 5, ZFS_SPACE_CHECK_RESERVED);
893 
894 	if (error == 0) {
895 		spa_write_cachefile(spa, B_FALSE, B_TRUE);
896 		spa_event_notify(spa, NULL, NULL, ESC_ZFS_POOL_REGUID);
897 	}
898 
899 	mutex_exit(&spa_namespace_lock);
900 	mutex_exit(&spa->spa_vdev_top_lock);
901 
902 	return (error);
903 }
904 
905 /*
906  * ==========================================================================
907  * SPA state manipulation (open/create/destroy/import/export)
908  * ==========================================================================
909  */
910 
911 static int
912 spa_error_entry_compare(const void *a, const void *b)
913 {
914 	const spa_error_entry_t *sa = (const spa_error_entry_t *)a;
915 	const spa_error_entry_t *sb = (const spa_error_entry_t *)b;
916 	int ret;
917 
918 	ret = memcmp(&sa->se_bookmark, &sb->se_bookmark,
919 	    sizeof (zbookmark_phys_t));
920 
921 	return (TREE_ISIGN(ret));
922 }
923 
924 /*
925  * Utility function which retrieves copies of the current logs and
926  * re-initializes them in the process.
927  */
928 void
929 spa_get_errlists(spa_t *spa, avl_tree_t *last, avl_tree_t *scrub)
930 {
931 	ASSERT(MUTEX_HELD(&spa->spa_errlist_lock));
932 
933 	bcopy(&spa->spa_errlist_last, last, sizeof (avl_tree_t));
934 	bcopy(&spa->spa_errlist_scrub, scrub, sizeof (avl_tree_t));
935 
936 	avl_create(&spa->spa_errlist_scrub,
937 	    spa_error_entry_compare, sizeof (spa_error_entry_t),
938 	    offsetof(spa_error_entry_t, se_avl));
939 	avl_create(&spa->spa_errlist_last,
940 	    spa_error_entry_compare, sizeof (spa_error_entry_t),
941 	    offsetof(spa_error_entry_t, se_avl));
942 }
943 
944 static void
945 spa_taskqs_init(spa_t *spa, zio_type_t t, zio_taskq_type_t q)
946 {
947 	const zio_taskq_info_t *ztip = &zio_taskqs[t][q];
948 	enum zti_modes mode = ztip->zti_mode;
949 	uint_t value = ztip->zti_value;
950 	uint_t count = ztip->zti_count;
951 	spa_taskqs_t *tqs = &spa->spa_zio_taskq[t][q];
952 	uint_t flags = 0;
953 	boolean_t batch = B_FALSE;
954 
955 	if (mode == ZTI_MODE_NULL) {
956 		tqs->stqs_count = 0;
957 		tqs->stqs_taskq = NULL;
958 		return;
959 	}
960 
961 	ASSERT3U(count, >, 0);
962 
963 	tqs->stqs_count = count;
964 	tqs->stqs_taskq = kmem_alloc(count * sizeof (taskq_t *), KM_SLEEP);
965 
966 	switch (mode) {
967 	case ZTI_MODE_FIXED:
968 		ASSERT3U(value, >=, 1);
969 		value = MAX(value, 1);
970 		flags |= TASKQ_DYNAMIC;
971 		break;
972 
973 	case ZTI_MODE_BATCH:
974 		batch = B_TRUE;
975 		flags |= TASKQ_THREADS_CPU_PCT;
976 		value = MIN(zio_taskq_batch_pct, 100);
977 		break;
978 
979 	default:
980 		panic("unrecognized mode for %s_%s taskq (%u:%u) in "
981 		    "spa_activate()",
982 		    zio_type_name[t], zio_taskq_types[q], mode, value);
983 		break;
984 	}
985 
986 	for (uint_t i = 0; i < count; i++) {
987 		taskq_t *tq;
988 		char name[32];
989 
990 		(void) snprintf(name, sizeof (name), "%s_%s",
991 		    zio_type_name[t], zio_taskq_types[q]);
992 
993 		if (zio_taskq_sysdc && spa->spa_proc != &p0) {
994 			if (batch)
995 				flags |= TASKQ_DC_BATCH;
996 
997 			tq = taskq_create_sysdc(name, value, 50, INT_MAX,
998 			    spa->spa_proc, zio_taskq_basedc, flags);
999 		} else {
1000 			pri_t pri = maxclsyspri;
1001 			/*
1002 			 * The write issue taskq can be extremely CPU
1003 			 * intensive.  Run it at slightly less important
1004 			 * priority than the other taskqs.
1005 			 *
1006 			 * Under Linux and FreeBSD this means incrementing
1007 			 * the priority value as opposed to platforms like
1008 			 * illumos where it should be decremented.
1009 			 *
1010 			 * On FreeBSD, if priorities divided by four (RQ_PPQ)
1011 			 * are equal then a difference between them is
1012 			 * insignificant.
1013 			 */
1014 			if (t == ZIO_TYPE_WRITE && q == ZIO_TASKQ_ISSUE) {
1015 #if defined(__linux__)
1016 				pri++;
1017 #elif defined(__FreeBSD__)
1018 				pri += 4;
1019 #else
1020 #error "unknown OS"
1021 #endif
1022 			}
1023 			tq = taskq_create_proc(name, value, pri, 50,
1024 			    INT_MAX, spa->spa_proc, flags);
1025 		}
1026 
1027 		tqs->stqs_taskq[i] = tq;
1028 	}
1029 }
1030 
1031 static void
1032 spa_taskqs_fini(spa_t *spa, zio_type_t t, zio_taskq_type_t q)
1033 {
1034 	spa_taskqs_t *tqs = &spa->spa_zio_taskq[t][q];
1035 
1036 	if (tqs->stqs_taskq == NULL) {
1037 		ASSERT3U(tqs->stqs_count, ==, 0);
1038 		return;
1039 	}
1040 
1041 	for (uint_t i = 0; i < tqs->stqs_count; i++) {
1042 		ASSERT3P(tqs->stqs_taskq[i], !=, NULL);
1043 		taskq_destroy(tqs->stqs_taskq[i]);
1044 	}
1045 
1046 	kmem_free(tqs->stqs_taskq, tqs->stqs_count * sizeof (taskq_t *));
1047 	tqs->stqs_taskq = NULL;
1048 }
1049 
1050 /*
1051  * Dispatch a task to the appropriate taskq for the ZFS I/O type and priority.
1052  * Note that a type may have multiple discrete taskqs to avoid lock contention
1053  * on the taskq itself. In that case we choose which taskq at random by using
1054  * the low bits of gethrtime().
1055  */
1056 void
1057 spa_taskq_dispatch_ent(spa_t *spa, zio_type_t t, zio_taskq_type_t q,
1058     task_func_t *func, void *arg, uint_t flags, taskq_ent_t *ent)
1059 {
1060 	spa_taskqs_t *tqs = &spa->spa_zio_taskq[t][q];
1061 	taskq_t *tq;
1062 
1063 	ASSERT3P(tqs->stqs_taskq, !=, NULL);
1064 	ASSERT3U(tqs->stqs_count, !=, 0);
1065 
1066 	if (tqs->stqs_count == 1) {
1067 		tq = tqs->stqs_taskq[0];
1068 	} else {
1069 		tq = tqs->stqs_taskq[((uint64_t)gethrtime()) % tqs->stqs_count];
1070 	}
1071 
1072 	taskq_dispatch_ent(tq, func, arg, flags, ent);
1073 }
1074 
1075 /*
1076  * Same as spa_taskq_dispatch_ent() but block on the task until completion.
1077  */
1078 void
1079 spa_taskq_dispatch_sync(spa_t *spa, zio_type_t t, zio_taskq_type_t q,
1080     task_func_t *func, void *arg, uint_t flags)
1081 {
1082 	spa_taskqs_t *tqs = &spa->spa_zio_taskq[t][q];
1083 	taskq_t *tq;
1084 	taskqid_t id;
1085 
1086 	ASSERT3P(tqs->stqs_taskq, !=, NULL);
1087 	ASSERT3U(tqs->stqs_count, !=, 0);
1088 
1089 	if (tqs->stqs_count == 1) {
1090 		tq = tqs->stqs_taskq[0];
1091 	} else {
1092 		tq = tqs->stqs_taskq[((uint64_t)gethrtime()) % tqs->stqs_count];
1093 	}
1094 
1095 	id = taskq_dispatch(tq, func, arg, flags);
1096 	if (id)
1097 		taskq_wait_id(tq, id);
1098 }
1099 
1100 static void
1101 spa_create_zio_taskqs(spa_t *spa)
1102 {
1103 	for (int t = 0; t < ZIO_TYPES; t++) {
1104 		for (int q = 0; q < ZIO_TASKQ_TYPES; q++) {
1105 			spa_taskqs_init(spa, t, q);
1106 		}
1107 	}
1108 }
1109 
1110 /*
1111  * Disabled until spa_thread() can be adapted for Linux.
1112  */
1113 #undef HAVE_SPA_THREAD
1114 
1115 #if defined(_KERNEL) && defined(HAVE_SPA_THREAD)
1116 static void
1117 spa_thread(void *arg)
1118 {
1119 	psetid_t zio_taskq_psrset_bind = PS_NONE;
1120 	callb_cpr_t cprinfo;
1121 
1122 	spa_t *spa = arg;
1123 	user_t *pu = PTOU(curproc);
1124 
1125 	CALLB_CPR_INIT(&cprinfo, &spa->spa_proc_lock, callb_generic_cpr,
1126 	    spa->spa_name);
1127 
1128 	ASSERT(curproc != &p0);
1129 	(void) snprintf(pu->u_psargs, sizeof (pu->u_psargs),
1130 	    "zpool-%s", spa->spa_name);
1131 	(void) strlcpy(pu->u_comm, pu->u_psargs, sizeof (pu->u_comm));
1132 
1133 	/* bind this thread to the requested psrset */
1134 	if (zio_taskq_psrset_bind != PS_NONE) {
1135 		pool_lock();
1136 		mutex_enter(&cpu_lock);
1137 		mutex_enter(&pidlock);
1138 		mutex_enter(&curproc->p_lock);
1139 
1140 		if (cpupart_bind_thread(curthread, zio_taskq_psrset_bind,
1141 		    0, NULL, NULL) == 0)  {
1142 			curthread->t_bind_pset = zio_taskq_psrset_bind;
1143 		} else {
1144 			cmn_err(CE_WARN,
1145 			    "Couldn't bind process for zfs pool \"%s\" to "
1146 			    "pset %d\n", spa->spa_name, zio_taskq_psrset_bind);
1147 		}
1148 
1149 		mutex_exit(&curproc->p_lock);
1150 		mutex_exit(&pidlock);
1151 		mutex_exit(&cpu_lock);
1152 		pool_unlock();
1153 	}
1154 
1155 	if (zio_taskq_sysdc) {
1156 		sysdc_thread_enter(curthread, 100, 0);
1157 	}
1158 
1159 	spa->spa_proc = curproc;
1160 	spa->spa_did = curthread->t_did;
1161 
1162 	spa_create_zio_taskqs(spa);
1163 
1164 	mutex_enter(&spa->spa_proc_lock);
1165 	ASSERT(spa->spa_proc_state == SPA_PROC_CREATED);
1166 
1167 	spa->spa_proc_state = SPA_PROC_ACTIVE;
1168 	cv_broadcast(&spa->spa_proc_cv);
1169 
1170 	CALLB_CPR_SAFE_BEGIN(&cprinfo);
1171 	while (spa->spa_proc_state == SPA_PROC_ACTIVE)
1172 		cv_wait(&spa->spa_proc_cv, &spa->spa_proc_lock);
1173 	CALLB_CPR_SAFE_END(&cprinfo, &spa->spa_proc_lock);
1174 
1175 	ASSERT(spa->spa_proc_state == SPA_PROC_DEACTIVATE);
1176 	spa->spa_proc_state = SPA_PROC_GONE;
1177 	spa->spa_proc = &p0;
1178 	cv_broadcast(&spa->spa_proc_cv);
1179 	CALLB_CPR_EXIT(&cprinfo);	/* drops spa_proc_lock */
1180 
1181 	mutex_enter(&curproc->p_lock);
1182 	lwp_exit();
1183 }
1184 #endif
1185 
1186 /*
1187  * Activate an uninitialized pool.
1188  */
1189 static void
1190 spa_activate(spa_t *spa, spa_mode_t mode)
1191 {
1192 	ASSERT(spa->spa_state == POOL_STATE_UNINITIALIZED);
1193 
1194 	spa->spa_state = POOL_STATE_ACTIVE;
1195 	spa->spa_mode = mode;
1196 
1197 	spa->spa_normal_class = metaslab_class_create(spa, zfs_metaslab_ops);
1198 	spa->spa_log_class = metaslab_class_create(spa, zfs_metaslab_ops);
1199 	spa->spa_special_class = metaslab_class_create(spa, zfs_metaslab_ops);
1200 	spa->spa_dedup_class = metaslab_class_create(spa, zfs_metaslab_ops);
1201 
1202 	/* Try to create a covering process */
1203 	mutex_enter(&spa->spa_proc_lock);
1204 	ASSERT(spa->spa_proc_state == SPA_PROC_NONE);
1205 	ASSERT(spa->spa_proc == &p0);
1206 	spa->spa_did = 0;
1207 
1208 #ifdef HAVE_SPA_THREAD
1209 	/* Only create a process if we're going to be around a while. */
1210 	if (spa_create_process && strcmp(spa->spa_name, TRYIMPORT_NAME) != 0) {
1211 		if (newproc(spa_thread, (caddr_t)spa, syscid, maxclsyspri,
1212 		    NULL, 0) == 0) {
1213 			spa->spa_proc_state = SPA_PROC_CREATED;
1214 			while (spa->spa_proc_state == SPA_PROC_CREATED) {
1215 				cv_wait(&spa->spa_proc_cv,
1216 				    &spa->spa_proc_lock);
1217 			}
1218 			ASSERT(spa->spa_proc_state == SPA_PROC_ACTIVE);
1219 			ASSERT(spa->spa_proc != &p0);
1220 			ASSERT(spa->spa_did != 0);
1221 		} else {
1222 #ifdef _KERNEL
1223 			cmn_err(CE_WARN,
1224 			    "Couldn't create process for zfs pool \"%s\"\n",
1225 			    spa->spa_name);
1226 #endif
1227 		}
1228 	}
1229 #endif /* HAVE_SPA_THREAD */
1230 	mutex_exit(&spa->spa_proc_lock);
1231 
1232 	/* If we didn't create a process, we need to create our taskqs. */
1233 	if (spa->spa_proc == &p0) {
1234 		spa_create_zio_taskqs(spa);
1235 	}
1236 
1237 	for (size_t i = 0; i < TXG_SIZE; i++) {
1238 		spa->spa_txg_zio[i] = zio_root(spa, NULL, NULL,
1239 		    ZIO_FLAG_CANFAIL);
1240 	}
1241 
1242 	list_create(&spa->spa_config_dirty_list, sizeof (vdev_t),
1243 	    offsetof(vdev_t, vdev_config_dirty_node));
1244 	list_create(&spa->spa_evicting_os_list, sizeof (objset_t),
1245 	    offsetof(objset_t, os_evicting_node));
1246 	list_create(&spa->spa_state_dirty_list, sizeof (vdev_t),
1247 	    offsetof(vdev_t, vdev_state_dirty_node));
1248 
1249 	txg_list_create(&spa->spa_vdev_txg_list, spa,
1250 	    offsetof(struct vdev, vdev_txg_node));
1251 
1252 	avl_create(&spa->spa_errlist_scrub,
1253 	    spa_error_entry_compare, sizeof (spa_error_entry_t),
1254 	    offsetof(spa_error_entry_t, se_avl));
1255 	avl_create(&spa->spa_errlist_last,
1256 	    spa_error_entry_compare, sizeof (spa_error_entry_t),
1257 	    offsetof(spa_error_entry_t, se_avl));
1258 
1259 	spa_keystore_init(&spa->spa_keystore);
1260 
1261 	/*
1262 	 * This taskq is used to perform zvol-minor-related tasks
1263 	 * asynchronously. This has several advantages, including easy
1264 	 * resolution of various deadlocks.
1265 	 *
1266 	 * The taskq must be single threaded to ensure tasks are always
1267 	 * processed in the order in which they were dispatched.
1268 	 *
1269 	 * A taskq per pool allows one to keep the pools independent.
1270 	 * This way if one pool is suspended, it will not impact another.
1271 	 *
1272 	 * The preferred location to dispatch a zvol minor task is a sync
1273 	 * task. In this context, there is easy access to the spa_t and minimal
1274 	 * error handling is required because the sync task must succeed.
1275 	 */
1276 	spa->spa_zvol_taskq = taskq_create("z_zvol", 1, defclsyspri,
1277 	    1, INT_MAX, 0);
1278 
1279 	/*
1280 	 * Taskq dedicated to prefetcher threads: this is used to prevent the
1281 	 * pool traverse code from monopolizing the global (and limited)
1282 	 * system_taskq by inappropriately scheduling long running tasks on it.
1283 	 */
1284 	spa->spa_prefetch_taskq = taskq_create("z_prefetch", 100,
1285 	    defclsyspri, 1, INT_MAX, TASKQ_DYNAMIC | TASKQ_THREADS_CPU_PCT);
1286 
1287 	/*
1288 	 * The taskq to upgrade datasets in this pool. Currently used by
1289 	 * feature SPA_FEATURE_USEROBJ_ACCOUNTING/SPA_FEATURE_PROJECT_QUOTA.
1290 	 */
1291 	spa->spa_upgrade_taskq = taskq_create("z_upgrade", 100,
1292 	    defclsyspri, 1, INT_MAX, TASKQ_DYNAMIC | TASKQ_THREADS_CPU_PCT);
1293 }
1294 
1295 /*
1296  * Opposite of spa_activate().
1297  */
1298 static void
1299 spa_deactivate(spa_t *spa)
1300 {
1301 	ASSERT(spa->spa_sync_on == B_FALSE);
1302 	ASSERT(spa->spa_dsl_pool == NULL);
1303 	ASSERT(spa->spa_root_vdev == NULL);
1304 	ASSERT(spa->spa_async_zio_root == NULL);
1305 	ASSERT(spa->spa_state != POOL_STATE_UNINITIALIZED);
1306 
1307 	spa_evicting_os_wait(spa);
1308 
1309 	if (spa->spa_zvol_taskq) {
1310 		taskq_destroy(spa->spa_zvol_taskq);
1311 		spa->spa_zvol_taskq = NULL;
1312 	}
1313 
1314 	if (spa->spa_prefetch_taskq) {
1315 		taskq_destroy(spa->spa_prefetch_taskq);
1316 		spa->spa_prefetch_taskq = NULL;
1317 	}
1318 
1319 	if (spa->spa_upgrade_taskq) {
1320 		taskq_destroy(spa->spa_upgrade_taskq);
1321 		spa->spa_upgrade_taskq = NULL;
1322 	}
1323 
1324 	txg_list_destroy(&spa->spa_vdev_txg_list);
1325 
1326 	list_destroy(&spa->spa_config_dirty_list);
1327 	list_destroy(&spa->spa_evicting_os_list);
1328 	list_destroy(&spa->spa_state_dirty_list);
1329 
1330 	taskq_cancel_id(system_delay_taskq, spa->spa_deadman_tqid);
1331 
1332 	for (int t = 0; t < ZIO_TYPES; t++) {
1333 		for (int q = 0; q < ZIO_TASKQ_TYPES; q++) {
1334 			spa_taskqs_fini(spa, t, q);
1335 		}
1336 	}
1337 
1338 	for (size_t i = 0; i < TXG_SIZE; i++) {
1339 		ASSERT3P(spa->spa_txg_zio[i], !=, NULL);
1340 		VERIFY0(zio_wait(spa->spa_txg_zio[i]));
1341 		spa->spa_txg_zio[i] = NULL;
1342 	}
1343 
1344 	metaslab_class_destroy(spa->spa_normal_class);
1345 	spa->spa_normal_class = NULL;
1346 
1347 	metaslab_class_destroy(spa->spa_log_class);
1348 	spa->spa_log_class = NULL;
1349 
1350 	metaslab_class_destroy(spa->spa_special_class);
1351 	spa->spa_special_class = NULL;
1352 
1353 	metaslab_class_destroy(spa->spa_dedup_class);
1354 	spa->spa_dedup_class = NULL;
1355 
1356 	/*
1357 	 * If this was part of an import or the open otherwise failed, we may
1358 	 * still have errors left in the queues.  Empty them just in case.
1359 	 */
1360 	spa_errlog_drain(spa);
1361 	avl_destroy(&spa->spa_errlist_scrub);
1362 	avl_destroy(&spa->spa_errlist_last);
1363 
1364 	spa_keystore_fini(&spa->spa_keystore);
1365 
1366 	spa->spa_state = POOL_STATE_UNINITIALIZED;
1367 
1368 	mutex_enter(&spa->spa_proc_lock);
1369 	if (spa->spa_proc_state != SPA_PROC_NONE) {
1370 		ASSERT(spa->spa_proc_state == SPA_PROC_ACTIVE);
1371 		spa->spa_proc_state = SPA_PROC_DEACTIVATE;
1372 		cv_broadcast(&spa->spa_proc_cv);
1373 		while (spa->spa_proc_state == SPA_PROC_DEACTIVATE) {
1374 			ASSERT(spa->spa_proc != &p0);
1375 			cv_wait(&spa->spa_proc_cv, &spa->spa_proc_lock);
1376 		}
1377 		ASSERT(spa->spa_proc_state == SPA_PROC_GONE);
1378 		spa->spa_proc_state = SPA_PROC_NONE;
1379 	}
1380 	ASSERT(spa->spa_proc == &p0);
1381 	mutex_exit(&spa->spa_proc_lock);
1382 
1383 	/*
1384 	 * We want to make sure spa_thread() has actually exited the ZFS
1385 	 * module, so that the module can't be unloaded out from underneath
1386 	 * it.
1387 	 */
1388 	if (spa->spa_did != 0) {
1389 		thread_join(spa->spa_did);
1390 		spa->spa_did = 0;
1391 	}
1392 }
1393 
1394 /*
1395  * Verify a pool configuration, and construct the vdev tree appropriately.  This
1396  * will create all the necessary vdevs in the appropriate layout, with each vdev
1397  * in the CLOSED state.  This will prep the pool before open/creation/import.
1398  * All vdev validation is done by the vdev_alloc() routine.
1399  */
1400 int
1401 spa_config_parse(spa_t *spa, vdev_t **vdp, nvlist_t *nv, vdev_t *parent,
1402     uint_t id, int atype)
1403 {
1404 	nvlist_t **child;
1405 	uint_t children;
1406 	int error;
1407 
1408 	if ((error = vdev_alloc(spa, vdp, nv, parent, id, atype)) != 0)
1409 		return (error);
1410 
1411 	if ((*vdp)->vdev_ops->vdev_op_leaf)
1412 		return (0);
1413 
1414 	error = nvlist_lookup_nvlist_array(nv, ZPOOL_CONFIG_CHILDREN,
1415 	    &child, &children);
1416 
1417 	if (error == ENOENT)
1418 		return (0);
1419 
1420 	if (error) {
1421 		vdev_free(*vdp);
1422 		*vdp = NULL;
1423 		return (SET_ERROR(EINVAL));
1424 	}
1425 
1426 	for (int c = 0; c < children; c++) {
1427 		vdev_t *vd;
1428 		if ((error = spa_config_parse(spa, &vd, child[c], *vdp, c,
1429 		    atype)) != 0) {
1430 			vdev_free(*vdp);
1431 			*vdp = NULL;
1432 			return (error);
1433 		}
1434 	}
1435 
1436 	ASSERT(*vdp != NULL);
1437 
1438 	return (0);
1439 }
1440 
1441 static boolean_t
1442 spa_should_flush_logs_on_unload(spa_t *spa)
1443 {
1444 	if (!spa_feature_is_active(spa, SPA_FEATURE_LOG_SPACEMAP))
1445 		return (B_FALSE);
1446 
1447 	if (!spa_writeable(spa))
1448 		return (B_FALSE);
1449 
1450 	if (!spa->spa_sync_on)
1451 		return (B_FALSE);
1452 
1453 	if (spa_state(spa) != POOL_STATE_EXPORTED)
1454 		return (B_FALSE);
1455 
1456 	if (zfs_keep_log_spacemaps_at_export)
1457 		return (B_FALSE);
1458 
1459 	return (B_TRUE);
1460 }
1461 
1462 /*
1463  * Opens a transaction that will set the flag that will instruct
1464  * spa_sync to attempt to flush all the metaslabs for that txg.
1465  */
1466 static void
1467 spa_unload_log_sm_flush_all(spa_t *spa)
1468 {
1469 	dmu_tx_t *tx = dmu_tx_create_dd(spa_get_dsl(spa)->dp_mos_dir);
1470 	VERIFY0(dmu_tx_assign(tx, TXG_WAIT));
1471 
1472 	ASSERT3U(spa->spa_log_flushall_txg, ==, 0);
1473 	spa->spa_log_flushall_txg = dmu_tx_get_txg(tx);
1474 
1475 	dmu_tx_commit(tx);
1476 	txg_wait_synced(spa_get_dsl(spa), spa->spa_log_flushall_txg);
1477 }
1478 
1479 static void
1480 spa_unload_log_sm_metadata(spa_t *spa)
1481 {
1482 	void *cookie = NULL;
1483 	spa_log_sm_t *sls;
1484 	while ((sls = avl_destroy_nodes(&spa->spa_sm_logs_by_txg,
1485 	    &cookie)) != NULL) {
1486 		VERIFY0(sls->sls_mscount);
1487 		kmem_free(sls, sizeof (spa_log_sm_t));
1488 	}
1489 
1490 	for (log_summary_entry_t *e = list_head(&spa->spa_log_summary);
1491 	    e != NULL; e = list_head(&spa->spa_log_summary)) {
1492 		VERIFY0(e->lse_mscount);
1493 		list_remove(&spa->spa_log_summary, e);
1494 		kmem_free(e, sizeof (log_summary_entry_t));
1495 	}
1496 
1497 	spa->spa_unflushed_stats.sus_nblocks = 0;
1498 	spa->spa_unflushed_stats.sus_memused = 0;
1499 	spa->spa_unflushed_stats.sus_blocklimit = 0;
1500 }
1501 
1502 static void
1503 spa_destroy_aux_threads(spa_t *spa)
1504 {
1505 	if (spa->spa_condense_zthr != NULL) {
1506 		zthr_destroy(spa->spa_condense_zthr);
1507 		spa->spa_condense_zthr = NULL;
1508 	}
1509 	if (spa->spa_checkpoint_discard_zthr != NULL) {
1510 		zthr_destroy(spa->spa_checkpoint_discard_zthr);
1511 		spa->spa_checkpoint_discard_zthr = NULL;
1512 	}
1513 	if (spa->spa_livelist_delete_zthr != NULL) {
1514 		zthr_destroy(spa->spa_livelist_delete_zthr);
1515 		spa->spa_livelist_delete_zthr = NULL;
1516 	}
1517 	if (spa->spa_livelist_condense_zthr != NULL) {
1518 		zthr_destroy(spa->spa_livelist_condense_zthr);
1519 		spa->spa_livelist_condense_zthr = NULL;
1520 	}
1521 }
1522 
1523 /*
1524  * Opposite of spa_load().
1525  */
1526 static void
1527 spa_unload(spa_t *spa)
1528 {
1529 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
1530 	ASSERT(spa_state(spa) != POOL_STATE_UNINITIALIZED);
1531 
1532 	spa_import_progress_remove(spa_guid(spa));
1533 	spa_load_note(spa, "UNLOADING");
1534 
1535 	spa_wake_waiters(spa);
1536 
1537 	/*
1538 	 * If the log space map feature is enabled and the pool is getting
1539 	 * exported (but not destroyed), we want to spend some time flushing
1540 	 * as many metaslabs as we can in an attempt to destroy log space
1541 	 * maps and save import time.
1542 	 */
1543 	if (spa_should_flush_logs_on_unload(spa))
1544 		spa_unload_log_sm_flush_all(spa);
1545 
1546 	/*
1547 	 * Stop async tasks.
1548 	 */
1549 	spa_async_suspend(spa);
1550 
1551 	if (spa->spa_root_vdev) {
1552 		vdev_t *root_vdev = spa->spa_root_vdev;
1553 		vdev_initialize_stop_all(root_vdev, VDEV_INITIALIZE_ACTIVE);
1554 		vdev_trim_stop_all(root_vdev, VDEV_TRIM_ACTIVE);
1555 		vdev_autotrim_stop_all(spa);
1556 		vdev_rebuild_stop_all(spa);
1557 	}
1558 
1559 	/*
1560 	 * Stop syncing.
1561 	 */
1562 	if (spa->spa_sync_on) {
1563 		txg_sync_stop(spa->spa_dsl_pool);
1564 		spa->spa_sync_on = B_FALSE;
1565 	}
1566 
1567 	/*
1568 	 * This ensures that there is no async metaslab prefetching
1569 	 * while we attempt to unload the spa.
1570 	 */
1571 	if (spa->spa_root_vdev != NULL) {
1572 		for (int c = 0; c < spa->spa_root_vdev->vdev_children; c++) {
1573 			vdev_t *vc = spa->spa_root_vdev->vdev_child[c];
1574 			if (vc->vdev_mg != NULL)
1575 				taskq_wait(vc->vdev_mg->mg_taskq);
1576 		}
1577 	}
1578 
1579 	if (spa->spa_mmp.mmp_thread)
1580 		mmp_thread_stop(spa);
1581 
1582 	/*
1583 	 * Wait for any outstanding async I/O to complete.
1584 	 */
1585 	if (spa->spa_async_zio_root != NULL) {
1586 		for (int i = 0; i < max_ncpus; i++)
1587 			(void) zio_wait(spa->spa_async_zio_root[i]);
1588 		kmem_free(spa->spa_async_zio_root, max_ncpus * sizeof (void *));
1589 		spa->spa_async_zio_root = NULL;
1590 	}
1591 
1592 	if (spa->spa_vdev_removal != NULL) {
1593 		spa_vdev_removal_destroy(spa->spa_vdev_removal);
1594 		spa->spa_vdev_removal = NULL;
1595 	}
1596 
1597 	spa_destroy_aux_threads(spa);
1598 
1599 	spa_condense_fini(spa);
1600 
1601 	bpobj_close(&spa->spa_deferred_bpobj);
1602 
1603 	spa_config_enter(spa, SCL_ALL, spa, RW_WRITER);
1604 
1605 	/*
1606 	 * Close all vdevs.
1607 	 */
1608 	if (spa->spa_root_vdev)
1609 		vdev_free(spa->spa_root_vdev);
1610 	ASSERT(spa->spa_root_vdev == NULL);
1611 
1612 	/*
1613 	 * Close the dsl pool.
1614 	 */
1615 	if (spa->spa_dsl_pool) {
1616 		dsl_pool_close(spa->spa_dsl_pool);
1617 		spa->spa_dsl_pool = NULL;
1618 		spa->spa_meta_objset = NULL;
1619 	}
1620 
1621 	ddt_unload(spa);
1622 	spa_unload_log_sm_metadata(spa);
1623 
1624 	/*
1625 	 * Drop and purge level 2 cache
1626 	 */
1627 	spa_l2cache_drop(spa);
1628 
1629 	for (int i = 0; i < spa->spa_spares.sav_count; i++)
1630 		vdev_free(spa->spa_spares.sav_vdevs[i]);
1631 	if (spa->spa_spares.sav_vdevs) {
1632 		kmem_free(spa->spa_spares.sav_vdevs,
1633 		    spa->spa_spares.sav_count * sizeof (void *));
1634 		spa->spa_spares.sav_vdevs = NULL;
1635 	}
1636 	if (spa->spa_spares.sav_config) {
1637 		nvlist_free(spa->spa_spares.sav_config);
1638 		spa->spa_spares.sav_config = NULL;
1639 	}
1640 	spa->spa_spares.sav_count = 0;
1641 
1642 	for (int i = 0; i < spa->spa_l2cache.sav_count; i++) {
1643 		vdev_clear_stats(spa->spa_l2cache.sav_vdevs[i]);
1644 		vdev_free(spa->spa_l2cache.sav_vdevs[i]);
1645 	}
1646 	if (spa->spa_l2cache.sav_vdevs) {
1647 		kmem_free(spa->spa_l2cache.sav_vdevs,
1648 		    spa->spa_l2cache.sav_count * sizeof (void *));
1649 		spa->spa_l2cache.sav_vdevs = NULL;
1650 	}
1651 	if (spa->spa_l2cache.sav_config) {
1652 		nvlist_free(spa->spa_l2cache.sav_config);
1653 		spa->spa_l2cache.sav_config = NULL;
1654 	}
1655 	spa->spa_l2cache.sav_count = 0;
1656 
1657 	spa->spa_async_suspended = 0;
1658 
1659 	spa->spa_indirect_vdevs_loaded = B_FALSE;
1660 
1661 	if (spa->spa_comment != NULL) {
1662 		spa_strfree(spa->spa_comment);
1663 		spa->spa_comment = NULL;
1664 	}
1665 
1666 	spa_config_exit(spa, SCL_ALL, spa);
1667 }
1668 
1669 /*
1670  * Load (or re-load) the current list of vdevs describing the active spares for
1671  * this pool.  When this is called, we have some form of basic information in
1672  * 'spa_spares.sav_config'.  We parse this into vdevs, try to open them, and
1673  * then re-generate a more complete list including status information.
1674  */
1675 void
1676 spa_load_spares(spa_t *spa)
1677 {
1678 	nvlist_t **spares;
1679 	uint_t nspares;
1680 	int i;
1681 	vdev_t *vd, *tvd;
1682 
1683 #ifndef _KERNEL
1684 	/*
1685 	 * zdb opens both the current state of the pool and the
1686 	 * checkpointed state (if present), with a different spa_t.
1687 	 *
1688 	 * As spare vdevs are shared among open pools, we skip loading
1689 	 * them when we load the checkpointed state of the pool.
1690 	 */
1691 	if (!spa_writeable(spa))
1692 		return;
1693 #endif
1694 
1695 	ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL);
1696 
1697 	/*
1698 	 * First, close and free any existing spare vdevs.
1699 	 */
1700 	for (i = 0; i < spa->spa_spares.sav_count; i++) {
1701 		vd = spa->spa_spares.sav_vdevs[i];
1702 
1703 		/* Undo the call to spa_activate() below */
1704 		if ((tvd = spa_lookup_by_guid(spa, vd->vdev_guid,
1705 		    B_FALSE)) != NULL && tvd->vdev_isspare)
1706 			spa_spare_remove(tvd);
1707 		vdev_close(vd);
1708 		vdev_free(vd);
1709 	}
1710 
1711 	if (spa->spa_spares.sav_vdevs)
1712 		kmem_free(spa->spa_spares.sav_vdevs,
1713 		    spa->spa_spares.sav_count * sizeof (void *));
1714 
1715 	if (spa->spa_spares.sav_config == NULL)
1716 		nspares = 0;
1717 	else
1718 		VERIFY(nvlist_lookup_nvlist_array(spa->spa_spares.sav_config,
1719 		    ZPOOL_CONFIG_SPARES, &spares, &nspares) == 0);
1720 
1721 	spa->spa_spares.sav_count = (int)nspares;
1722 	spa->spa_spares.sav_vdevs = NULL;
1723 
1724 	if (nspares == 0)
1725 		return;
1726 
1727 	/*
1728 	 * Construct the array of vdevs, opening them to get status in the
1729 	 * process.   For each spare, there is potentially two different vdev_t
1730 	 * structures associated with it: one in the list of spares (used only
1731 	 * for basic validation purposes) and one in the active vdev
1732 	 * configuration (if it's spared in).  During this phase we open and
1733 	 * validate each vdev on the spare list.  If the vdev also exists in the
1734 	 * active configuration, then we also mark this vdev as an active spare.
1735 	 */
1736 	spa->spa_spares.sav_vdevs = kmem_zalloc(nspares * sizeof (void *),
1737 	    KM_SLEEP);
1738 	for (i = 0; i < spa->spa_spares.sav_count; i++) {
1739 		VERIFY(spa_config_parse(spa, &vd, spares[i], NULL, 0,
1740 		    VDEV_ALLOC_SPARE) == 0);
1741 		ASSERT(vd != NULL);
1742 
1743 		spa->spa_spares.sav_vdevs[i] = vd;
1744 
1745 		if ((tvd = spa_lookup_by_guid(spa, vd->vdev_guid,
1746 		    B_FALSE)) != NULL) {
1747 			if (!tvd->vdev_isspare)
1748 				spa_spare_add(tvd);
1749 
1750 			/*
1751 			 * We only mark the spare active if we were successfully
1752 			 * able to load the vdev.  Otherwise, importing a pool
1753 			 * with a bad active spare would result in strange
1754 			 * behavior, because multiple pool would think the spare
1755 			 * is actively in use.
1756 			 *
1757 			 * There is a vulnerability here to an equally bizarre
1758 			 * circumstance, where a dead active spare is later
1759 			 * brought back to life (onlined or otherwise).  Given
1760 			 * the rarity of this scenario, and the extra complexity
1761 			 * it adds, we ignore the possibility.
1762 			 */
1763 			if (!vdev_is_dead(tvd))
1764 				spa_spare_activate(tvd);
1765 		}
1766 
1767 		vd->vdev_top = vd;
1768 		vd->vdev_aux = &spa->spa_spares;
1769 
1770 		if (vdev_open(vd) != 0)
1771 			continue;
1772 
1773 		if (vdev_validate_aux(vd) == 0)
1774 			spa_spare_add(vd);
1775 	}
1776 
1777 	/*
1778 	 * Recompute the stashed list of spares, with status information
1779 	 * this time.
1780 	 */
1781 	VERIFY(nvlist_remove(spa->spa_spares.sav_config, ZPOOL_CONFIG_SPARES,
1782 	    DATA_TYPE_NVLIST_ARRAY) == 0);
1783 
1784 	spares = kmem_alloc(spa->spa_spares.sav_count * sizeof (void *),
1785 	    KM_SLEEP);
1786 	for (i = 0; i < spa->spa_spares.sav_count; i++)
1787 		spares[i] = vdev_config_generate(spa,
1788 		    spa->spa_spares.sav_vdevs[i], B_TRUE, VDEV_CONFIG_SPARE);
1789 	VERIFY(nvlist_add_nvlist_array(spa->spa_spares.sav_config,
1790 	    ZPOOL_CONFIG_SPARES, spares, spa->spa_spares.sav_count) == 0);
1791 	for (i = 0; i < spa->spa_spares.sav_count; i++)
1792 		nvlist_free(spares[i]);
1793 	kmem_free(spares, spa->spa_spares.sav_count * sizeof (void *));
1794 }
1795 
1796 /*
1797  * Load (or re-load) the current list of vdevs describing the active l2cache for
1798  * this pool.  When this is called, we have some form of basic information in
1799  * 'spa_l2cache.sav_config'.  We parse this into vdevs, try to open them, and
1800  * then re-generate a more complete list including status information.
1801  * Devices which are already active have their details maintained, and are
1802  * not re-opened.
1803  */
1804 void
1805 spa_load_l2cache(spa_t *spa)
1806 {
1807 	nvlist_t **l2cache = NULL;
1808 	uint_t nl2cache;
1809 	int i, j, oldnvdevs;
1810 	uint64_t guid;
1811 	vdev_t *vd, **oldvdevs, **newvdevs;
1812 	spa_aux_vdev_t *sav = &spa->spa_l2cache;
1813 
1814 #ifndef _KERNEL
1815 	/*
1816 	 * zdb opens both the current state of the pool and the
1817 	 * checkpointed state (if present), with a different spa_t.
1818 	 *
1819 	 * As L2 caches are part of the ARC which is shared among open
1820 	 * pools, we skip loading them when we load the checkpointed
1821 	 * state of the pool.
1822 	 */
1823 	if (!spa_writeable(spa))
1824 		return;
1825 #endif
1826 
1827 	ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL);
1828 
1829 	oldvdevs = sav->sav_vdevs;
1830 	oldnvdevs = sav->sav_count;
1831 	sav->sav_vdevs = NULL;
1832 	sav->sav_count = 0;
1833 
1834 	if (sav->sav_config == NULL) {
1835 		nl2cache = 0;
1836 		newvdevs = NULL;
1837 		goto out;
1838 	}
1839 
1840 	VERIFY(nvlist_lookup_nvlist_array(sav->sav_config,
1841 	    ZPOOL_CONFIG_L2CACHE, &l2cache, &nl2cache) == 0);
1842 	newvdevs = kmem_alloc(nl2cache * sizeof (void *), KM_SLEEP);
1843 
1844 	/*
1845 	 * Process new nvlist of vdevs.
1846 	 */
1847 	for (i = 0; i < nl2cache; i++) {
1848 		VERIFY(nvlist_lookup_uint64(l2cache[i], ZPOOL_CONFIG_GUID,
1849 		    &guid) == 0);
1850 
1851 		newvdevs[i] = NULL;
1852 		for (j = 0; j < oldnvdevs; j++) {
1853 			vd = oldvdevs[j];
1854 			if (vd != NULL && guid == vd->vdev_guid) {
1855 				/*
1856 				 * Retain previous vdev for add/remove ops.
1857 				 */
1858 				newvdevs[i] = vd;
1859 				oldvdevs[j] = NULL;
1860 				break;
1861 			}
1862 		}
1863 
1864 		if (newvdevs[i] == NULL) {
1865 			/*
1866 			 * Create new vdev
1867 			 */
1868 			VERIFY(spa_config_parse(spa, &vd, l2cache[i], NULL, 0,
1869 			    VDEV_ALLOC_L2CACHE) == 0);
1870 			ASSERT(vd != NULL);
1871 			newvdevs[i] = vd;
1872 
1873 			/*
1874 			 * Commit this vdev as an l2cache device,
1875 			 * even if it fails to open.
1876 			 */
1877 			spa_l2cache_add(vd);
1878 
1879 			vd->vdev_top = vd;
1880 			vd->vdev_aux = sav;
1881 
1882 			spa_l2cache_activate(vd);
1883 
1884 			if (vdev_open(vd) != 0)
1885 				continue;
1886 
1887 			(void) vdev_validate_aux(vd);
1888 
1889 			if (!vdev_is_dead(vd))
1890 				l2arc_add_vdev(spa, vd);
1891 
1892 			/*
1893 			 * Upon cache device addition to a pool or pool
1894 			 * creation with a cache device or if the header
1895 			 * of the device is invalid we issue an async
1896 			 * TRIM command for the whole device which will
1897 			 * execute if l2arc_trim_ahead > 0.
1898 			 */
1899 			spa_async_request(spa, SPA_ASYNC_L2CACHE_TRIM);
1900 		}
1901 	}
1902 
1903 	sav->sav_vdevs = newvdevs;
1904 	sav->sav_count = (int)nl2cache;
1905 
1906 	/*
1907 	 * Recompute the stashed list of l2cache devices, with status
1908 	 * information this time.
1909 	 */
1910 	VERIFY(nvlist_remove(sav->sav_config, ZPOOL_CONFIG_L2CACHE,
1911 	    DATA_TYPE_NVLIST_ARRAY) == 0);
1912 
1913 	if (sav->sav_count > 0)
1914 		l2cache = kmem_alloc(sav->sav_count * sizeof (void *),
1915 		    KM_SLEEP);
1916 	for (i = 0; i < sav->sav_count; i++)
1917 		l2cache[i] = vdev_config_generate(spa,
1918 		    sav->sav_vdevs[i], B_TRUE, VDEV_CONFIG_L2CACHE);
1919 	VERIFY(nvlist_add_nvlist_array(sav->sav_config,
1920 	    ZPOOL_CONFIG_L2CACHE, l2cache, sav->sav_count) == 0);
1921 
1922 out:
1923 	/*
1924 	 * Purge vdevs that were dropped
1925 	 */
1926 	for (i = 0; i < oldnvdevs; i++) {
1927 		uint64_t pool;
1928 
1929 		vd = oldvdevs[i];
1930 		if (vd != NULL) {
1931 			ASSERT(vd->vdev_isl2cache);
1932 
1933 			if (spa_l2cache_exists(vd->vdev_guid, &pool) &&
1934 			    pool != 0ULL && l2arc_vdev_present(vd))
1935 				l2arc_remove_vdev(vd);
1936 			vdev_clear_stats(vd);
1937 			vdev_free(vd);
1938 		}
1939 	}
1940 
1941 	if (oldvdevs)
1942 		kmem_free(oldvdevs, oldnvdevs * sizeof (void *));
1943 
1944 	for (i = 0; i < sav->sav_count; i++)
1945 		nvlist_free(l2cache[i]);
1946 	if (sav->sav_count)
1947 		kmem_free(l2cache, sav->sav_count * sizeof (void *));
1948 }
1949 
1950 static int
1951 load_nvlist(spa_t *spa, uint64_t obj, nvlist_t **value)
1952 {
1953 	dmu_buf_t *db;
1954 	char *packed = NULL;
1955 	size_t nvsize = 0;
1956 	int error;
1957 	*value = NULL;
1958 
1959 	error = dmu_bonus_hold(spa->spa_meta_objset, obj, FTAG, &db);
1960 	if (error)
1961 		return (error);
1962 
1963 	nvsize = *(uint64_t *)db->db_data;
1964 	dmu_buf_rele(db, FTAG);
1965 
1966 	packed = vmem_alloc(nvsize, KM_SLEEP);
1967 	error = dmu_read(spa->spa_meta_objset, obj, 0, nvsize, packed,
1968 	    DMU_READ_PREFETCH);
1969 	if (error == 0)
1970 		error = nvlist_unpack(packed, nvsize, value, 0);
1971 	vmem_free(packed, nvsize);
1972 
1973 	return (error);
1974 }
1975 
1976 /*
1977  * Concrete top-level vdevs that are not missing and are not logs. At every
1978  * spa_sync we write new uberblocks to at least SPA_SYNC_MIN_VDEVS core tvds.
1979  */
1980 static uint64_t
1981 spa_healthy_core_tvds(spa_t *spa)
1982 {
1983 	vdev_t *rvd = spa->spa_root_vdev;
1984 	uint64_t tvds = 0;
1985 
1986 	for (uint64_t i = 0; i < rvd->vdev_children; i++) {
1987 		vdev_t *vd = rvd->vdev_child[i];
1988 		if (vd->vdev_islog)
1989 			continue;
1990 		if (vdev_is_concrete(vd) && !vdev_is_dead(vd))
1991 			tvds++;
1992 	}
1993 
1994 	return (tvds);
1995 }
1996 
1997 /*
1998  * Checks to see if the given vdev could not be opened, in which case we post a
1999  * sysevent to notify the autoreplace code that the device has been removed.
2000  */
2001 static void
2002 spa_check_removed(vdev_t *vd)
2003 {
2004 	for (uint64_t c = 0; c < vd->vdev_children; c++)
2005 		spa_check_removed(vd->vdev_child[c]);
2006 
2007 	if (vd->vdev_ops->vdev_op_leaf && vdev_is_dead(vd) &&
2008 	    vdev_is_concrete(vd)) {
2009 		zfs_post_autoreplace(vd->vdev_spa, vd);
2010 		spa_event_notify(vd->vdev_spa, vd, NULL, ESC_ZFS_VDEV_CHECK);
2011 	}
2012 }
2013 
2014 static int
2015 spa_check_for_missing_logs(spa_t *spa)
2016 {
2017 	vdev_t *rvd = spa->spa_root_vdev;
2018 
2019 	/*
2020 	 * If we're doing a normal import, then build up any additional
2021 	 * diagnostic information about missing log devices.
2022 	 * We'll pass this up to the user for further processing.
2023 	 */
2024 	if (!(spa->spa_import_flags & ZFS_IMPORT_MISSING_LOG)) {
2025 		nvlist_t **child, *nv;
2026 		uint64_t idx = 0;
2027 
2028 		child = kmem_alloc(rvd->vdev_children * sizeof (nvlist_t *),
2029 		    KM_SLEEP);
2030 		VERIFY(nvlist_alloc(&nv, NV_UNIQUE_NAME, KM_SLEEP) == 0);
2031 
2032 		for (uint64_t c = 0; c < rvd->vdev_children; c++) {
2033 			vdev_t *tvd = rvd->vdev_child[c];
2034 
2035 			/*
2036 			 * We consider a device as missing only if it failed
2037 			 * to open (i.e. offline or faulted is not considered
2038 			 * as missing).
2039 			 */
2040 			if (tvd->vdev_islog &&
2041 			    tvd->vdev_state == VDEV_STATE_CANT_OPEN) {
2042 				child[idx++] = vdev_config_generate(spa, tvd,
2043 				    B_FALSE, VDEV_CONFIG_MISSING);
2044 			}
2045 		}
2046 
2047 		if (idx > 0) {
2048 			fnvlist_add_nvlist_array(nv,
2049 			    ZPOOL_CONFIG_CHILDREN, child, idx);
2050 			fnvlist_add_nvlist(spa->spa_load_info,
2051 			    ZPOOL_CONFIG_MISSING_DEVICES, nv);
2052 
2053 			for (uint64_t i = 0; i < idx; i++)
2054 				nvlist_free(child[i]);
2055 		}
2056 		nvlist_free(nv);
2057 		kmem_free(child, rvd->vdev_children * sizeof (char **));
2058 
2059 		if (idx > 0) {
2060 			spa_load_failed(spa, "some log devices are missing");
2061 			vdev_dbgmsg_print_tree(rvd, 2);
2062 			return (SET_ERROR(ENXIO));
2063 		}
2064 	} else {
2065 		for (uint64_t c = 0; c < rvd->vdev_children; c++) {
2066 			vdev_t *tvd = rvd->vdev_child[c];
2067 
2068 			if (tvd->vdev_islog &&
2069 			    tvd->vdev_state == VDEV_STATE_CANT_OPEN) {
2070 				spa_set_log_state(spa, SPA_LOG_CLEAR);
2071 				spa_load_note(spa, "some log devices are "
2072 				    "missing, ZIL is dropped.");
2073 				vdev_dbgmsg_print_tree(rvd, 2);
2074 				break;
2075 			}
2076 		}
2077 	}
2078 
2079 	return (0);
2080 }
2081 
2082 /*
2083  * Check for missing log devices
2084  */
2085 static boolean_t
2086 spa_check_logs(spa_t *spa)
2087 {
2088 	boolean_t rv = B_FALSE;
2089 	dsl_pool_t *dp = spa_get_dsl(spa);
2090 
2091 	switch (spa->spa_log_state) {
2092 	default:
2093 		break;
2094 	case SPA_LOG_MISSING:
2095 		/* need to recheck in case slog has been restored */
2096 	case SPA_LOG_UNKNOWN:
2097 		rv = (dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
2098 		    zil_check_log_chain, NULL, DS_FIND_CHILDREN) != 0);
2099 		if (rv)
2100 			spa_set_log_state(spa, SPA_LOG_MISSING);
2101 		break;
2102 	}
2103 	return (rv);
2104 }
2105 
2106 static boolean_t
2107 spa_passivate_log(spa_t *spa)
2108 {
2109 	vdev_t *rvd = spa->spa_root_vdev;
2110 	boolean_t slog_found = B_FALSE;
2111 
2112 	ASSERT(spa_config_held(spa, SCL_ALLOC, RW_WRITER));
2113 
2114 	for (int c = 0; c < rvd->vdev_children; c++) {
2115 		vdev_t *tvd = rvd->vdev_child[c];
2116 		metaslab_group_t *mg = tvd->vdev_mg;
2117 
2118 		if (tvd->vdev_islog) {
2119 			metaslab_group_passivate(mg);
2120 			slog_found = B_TRUE;
2121 		}
2122 	}
2123 
2124 	return (slog_found);
2125 }
2126 
2127 static void
2128 spa_activate_log(spa_t *spa)
2129 {
2130 	vdev_t *rvd = spa->spa_root_vdev;
2131 
2132 	ASSERT(spa_config_held(spa, SCL_ALLOC, RW_WRITER));
2133 
2134 	for (int c = 0; c < rvd->vdev_children; c++) {
2135 		vdev_t *tvd = rvd->vdev_child[c];
2136 		metaslab_group_t *mg = tvd->vdev_mg;
2137 
2138 		if (tvd->vdev_islog)
2139 			metaslab_group_activate(mg);
2140 	}
2141 }
2142 
2143 int
2144 spa_reset_logs(spa_t *spa)
2145 {
2146 	int error;
2147 
2148 	error = dmu_objset_find(spa_name(spa), zil_reset,
2149 	    NULL, DS_FIND_CHILDREN);
2150 	if (error == 0) {
2151 		/*
2152 		 * We successfully offlined the log device, sync out the
2153 		 * current txg so that the "stubby" block can be removed
2154 		 * by zil_sync().
2155 		 */
2156 		txg_wait_synced(spa->spa_dsl_pool, 0);
2157 	}
2158 	return (error);
2159 }
2160 
2161 static void
2162 spa_aux_check_removed(spa_aux_vdev_t *sav)
2163 {
2164 	for (int i = 0; i < sav->sav_count; i++)
2165 		spa_check_removed(sav->sav_vdevs[i]);
2166 }
2167 
2168 void
2169 spa_claim_notify(zio_t *zio)
2170 {
2171 	spa_t *spa = zio->io_spa;
2172 
2173 	if (zio->io_error)
2174 		return;
2175 
2176 	mutex_enter(&spa->spa_props_lock);	/* any mutex will do */
2177 	if (spa->spa_claim_max_txg < zio->io_bp->blk_birth)
2178 		spa->spa_claim_max_txg = zio->io_bp->blk_birth;
2179 	mutex_exit(&spa->spa_props_lock);
2180 }
2181 
2182 typedef struct spa_load_error {
2183 	uint64_t	sle_meta_count;
2184 	uint64_t	sle_data_count;
2185 } spa_load_error_t;
2186 
2187 static void
2188 spa_load_verify_done(zio_t *zio)
2189 {
2190 	blkptr_t *bp = zio->io_bp;
2191 	spa_load_error_t *sle = zio->io_private;
2192 	dmu_object_type_t type = BP_GET_TYPE(bp);
2193 	int error = zio->io_error;
2194 	spa_t *spa = zio->io_spa;
2195 
2196 	abd_free(zio->io_abd);
2197 	if (error) {
2198 		if ((BP_GET_LEVEL(bp) != 0 || DMU_OT_IS_METADATA(type)) &&
2199 		    type != DMU_OT_INTENT_LOG)
2200 			atomic_inc_64(&sle->sle_meta_count);
2201 		else
2202 			atomic_inc_64(&sle->sle_data_count);
2203 	}
2204 
2205 	mutex_enter(&spa->spa_scrub_lock);
2206 	spa->spa_load_verify_bytes -= BP_GET_PSIZE(bp);
2207 	cv_broadcast(&spa->spa_scrub_io_cv);
2208 	mutex_exit(&spa->spa_scrub_lock);
2209 }
2210 
2211 /*
2212  * Maximum number of inflight bytes is the log2 fraction of the arc size.
2213  * By default, we set it to 1/16th of the arc.
2214  */
2215 int spa_load_verify_shift = 4;
2216 int spa_load_verify_metadata = B_TRUE;
2217 int spa_load_verify_data = B_TRUE;
2218 
2219 /*ARGSUSED*/
2220 static int
2221 spa_load_verify_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
2222     const zbookmark_phys_t *zb, const dnode_phys_t *dnp, void *arg)
2223 {
2224 	if (zb->zb_level == ZB_DNODE_LEVEL || BP_IS_HOLE(bp) ||
2225 	    BP_IS_EMBEDDED(bp) || BP_IS_REDACTED(bp))
2226 		return (0);
2227 	/*
2228 	 * Note: normally this routine will not be called if
2229 	 * spa_load_verify_metadata is not set.  However, it may be useful
2230 	 * to manually set the flag after the traversal has begun.
2231 	 */
2232 	if (!spa_load_verify_metadata)
2233 		return (0);
2234 	if (!BP_IS_METADATA(bp) && !spa_load_verify_data)
2235 		return (0);
2236 
2237 	uint64_t maxinflight_bytes =
2238 	    arc_target_bytes() >> spa_load_verify_shift;
2239 	zio_t *rio = arg;
2240 	size_t size = BP_GET_PSIZE(bp);
2241 
2242 	mutex_enter(&spa->spa_scrub_lock);
2243 	while (spa->spa_load_verify_bytes >= maxinflight_bytes)
2244 		cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock);
2245 	spa->spa_load_verify_bytes += size;
2246 	mutex_exit(&spa->spa_scrub_lock);
2247 
2248 	zio_nowait(zio_read(rio, spa, bp, abd_alloc_for_io(size, B_FALSE), size,
2249 	    spa_load_verify_done, rio->io_private, ZIO_PRIORITY_SCRUB,
2250 	    ZIO_FLAG_SPECULATIVE | ZIO_FLAG_CANFAIL |
2251 	    ZIO_FLAG_SCRUB | ZIO_FLAG_RAW, zb));
2252 	return (0);
2253 }
2254 
2255 /* ARGSUSED */
2256 static int
2257 verify_dataset_name_len(dsl_pool_t *dp, dsl_dataset_t *ds, void *arg)
2258 {
2259 	if (dsl_dataset_namelen(ds) >= ZFS_MAX_DATASET_NAME_LEN)
2260 		return (SET_ERROR(ENAMETOOLONG));
2261 
2262 	return (0);
2263 }
2264 
2265 static int
2266 spa_load_verify(spa_t *spa)
2267 {
2268 	zio_t *rio;
2269 	spa_load_error_t sle = { 0 };
2270 	zpool_load_policy_t policy;
2271 	boolean_t verify_ok = B_FALSE;
2272 	int error = 0;
2273 
2274 	zpool_get_load_policy(spa->spa_config, &policy);
2275 
2276 	if (policy.zlp_rewind & ZPOOL_NEVER_REWIND)
2277 		return (0);
2278 
2279 	dsl_pool_config_enter(spa->spa_dsl_pool, FTAG);
2280 	error = dmu_objset_find_dp(spa->spa_dsl_pool,
2281 	    spa->spa_dsl_pool->dp_root_dir_obj, verify_dataset_name_len, NULL,
2282 	    DS_FIND_CHILDREN);
2283 	dsl_pool_config_exit(spa->spa_dsl_pool, FTAG);
2284 	if (error != 0)
2285 		return (error);
2286 
2287 	rio = zio_root(spa, NULL, &sle,
2288 	    ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE);
2289 
2290 	if (spa_load_verify_metadata) {
2291 		if (spa->spa_extreme_rewind) {
2292 			spa_load_note(spa, "performing a complete scan of the "
2293 			    "pool since extreme rewind is on. This may take "
2294 			    "a very long time.\n  (spa_load_verify_data=%u, "
2295 			    "spa_load_verify_metadata=%u)",
2296 			    spa_load_verify_data, spa_load_verify_metadata);
2297 		}
2298 
2299 		error = traverse_pool(spa, spa->spa_verify_min_txg,
2300 		    TRAVERSE_PRE | TRAVERSE_PREFETCH_METADATA |
2301 		    TRAVERSE_NO_DECRYPT, spa_load_verify_cb, rio);
2302 	}
2303 
2304 	(void) zio_wait(rio);
2305 	ASSERT0(spa->spa_load_verify_bytes);
2306 
2307 	spa->spa_load_meta_errors = sle.sle_meta_count;
2308 	spa->spa_load_data_errors = sle.sle_data_count;
2309 
2310 	if (sle.sle_meta_count != 0 || sle.sle_data_count != 0) {
2311 		spa_load_note(spa, "spa_load_verify found %llu metadata errors "
2312 		    "and %llu data errors", (u_longlong_t)sle.sle_meta_count,
2313 		    (u_longlong_t)sle.sle_data_count);
2314 	}
2315 
2316 	if (spa_load_verify_dryrun ||
2317 	    (!error && sle.sle_meta_count <= policy.zlp_maxmeta &&
2318 	    sle.sle_data_count <= policy.zlp_maxdata)) {
2319 		int64_t loss = 0;
2320 
2321 		verify_ok = B_TRUE;
2322 		spa->spa_load_txg = spa->spa_uberblock.ub_txg;
2323 		spa->spa_load_txg_ts = spa->spa_uberblock.ub_timestamp;
2324 
2325 		loss = spa->spa_last_ubsync_txg_ts - spa->spa_load_txg_ts;
2326 		VERIFY(nvlist_add_uint64(spa->spa_load_info,
2327 		    ZPOOL_CONFIG_LOAD_TIME, spa->spa_load_txg_ts) == 0);
2328 		VERIFY(nvlist_add_int64(spa->spa_load_info,
2329 		    ZPOOL_CONFIG_REWIND_TIME, loss) == 0);
2330 		VERIFY(nvlist_add_uint64(spa->spa_load_info,
2331 		    ZPOOL_CONFIG_LOAD_DATA_ERRORS, sle.sle_data_count) == 0);
2332 	} else {
2333 		spa->spa_load_max_txg = spa->spa_uberblock.ub_txg;
2334 	}
2335 
2336 	if (spa_load_verify_dryrun)
2337 		return (0);
2338 
2339 	if (error) {
2340 		if (error != ENXIO && error != EIO)
2341 			error = SET_ERROR(EIO);
2342 		return (error);
2343 	}
2344 
2345 	return (verify_ok ? 0 : EIO);
2346 }
2347 
2348 /*
2349  * Find a value in the pool props object.
2350  */
2351 static void
2352 spa_prop_find(spa_t *spa, zpool_prop_t prop, uint64_t *val)
2353 {
2354 	(void) zap_lookup(spa->spa_meta_objset, spa->spa_pool_props_object,
2355 	    zpool_prop_to_name(prop), sizeof (uint64_t), 1, val);
2356 }
2357 
2358 /*
2359  * Find a value in the pool directory object.
2360  */
2361 static int
2362 spa_dir_prop(spa_t *spa, const char *name, uint64_t *val, boolean_t log_enoent)
2363 {
2364 	int error = zap_lookup(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
2365 	    name, sizeof (uint64_t), 1, val);
2366 
2367 	if (error != 0 && (error != ENOENT || log_enoent)) {
2368 		spa_load_failed(spa, "couldn't get '%s' value in MOS directory "
2369 		    "[error=%d]", name, error);
2370 	}
2371 
2372 	return (error);
2373 }
2374 
2375 static int
2376 spa_vdev_err(vdev_t *vdev, vdev_aux_t aux, int err)
2377 {
2378 	vdev_set_state(vdev, B_TRUE, VDEV_STATE_CANT_OPEN, aux);
2379 	return (SET_ERROR(err));
2380 }
2381 
2382 boolean_t
2383 spa_livelist_delete_check(spa_t *spa)
2384 {
2385 	return (spa->spa_livelists_to_delete != 0);
2386 }
2387 
2388 /* ARGSUSED */
2389 static boolean_t
2390 spa_livelist_delete_cb_check(void *arg, zthr_t *z)
2391 {
2392 	spa_t *spa = arg;
2393 	return (spa_livelist_delete_check(spa));
2394 }
2395 
2396 static int
2397 delete_blkptr_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
2398 {
2399 	spa_t *spa = arg;
2400 	zio_free(spa, tx->tx_txg, bp);
2401 	dsl_dir_diduse_space(tx->tx_pool->dp_free_dir, DD_USED_HEAD,
2402 	    -bp_get_dsize_sync(spa, bp),
2403 	    -BP_GET_PSIZE(bp), -BP_GET_UCSIZE(bp), tx);
2404 	return (0);
2405 }
2406 
2407 static int
2408 dsl_get_next_livelist_obj(objset_t *os, uint64_t zap_obj, uint64_t *llp)
2409 {
2410 	int err;
2411 	zap_cursor_t zc;
2412 	zap_attribute_t za;
2413 	zap_cursor_init(&zc, os, zap_obj);
2414 	err = zap_cursor_retrieve(&zc, &za);
2415 	zap_cursor_fini(&zc);
2416 	if (err == 0)
2417 		*llp = za.za_first_integer;
2418 	return (err);
2419 }
2420 
2421 /*
2422  * Components of livelist deletion that must be performed in syncing
2423  * context: freeing block pointers and updating the pool-wide data
2424  * structures to indicate how much work is left to do
2425  */
2426 typedef struct sublist_delete_arg {
2427 	spa_t *spa;
2428 	dsl_deadlist_t *ll;
2429 	uint64_t key;
2430 	bplist_t *to_free;
2431 } sublist_delete_arg_t;
2432 
2433 static void
2434 sublist_delete_sync(void *arg, dmu_tx_t *tx)
2435 {
2436 	sublist_delete_arg_t *sda = arg;
2437 	spa_t *spa = sda->spa;
2438 	dsl_deadlist_t *ll = sda->ll;
2439 	uint64_t key = sda->key;
2440 	bplist_t *to_free = sda->to_free;
2441 
2442 	bplist_iterate(to_free, delete_blkptr_cb, spa, tx);
2443 	dsl_deadlist_remove_entry(ll, key, tx);
2444 }
2445 
2446 typedef struct livelist_delete_arg {
2447 	spa_t *spa;
2448 	uint64_t ll_obj;
2449 	uint64_t zap_obj;
2450 } livelist_delete_arg_t;
2451 
2452 static void
2453 livelist_delete_sync(void *arg, dmu_tx_t *tx)
2454 {
2455 	livelist_delete_arg_t *lda = arg;
2456 	spa_t *spa = lda->spa;
2457 	uint64_t ll_obj = lda->ll_obj;
2458 	uint64_t zap_obj = lda->zap_obj;
2459 	objset_t *mos = spa->spa_meta_objset;
2460 	uint64_t count;
2461 
2462 	/* free the livelist and decrement the feature count */
2463 	VERIFY0(zap_remove_int(mos, zap_obj, ll_obj, tx));
2464 	dsl_deadlist_free(mos, ll_obj, tx);
2465 	spa_feature_decr(spa, SPA_FEATURE_LIVELIST, tx);
2466 	VERIFY0(zap_count(mos, zap_obj, &count));
2467 	if (count == 0) {
2468 		/* no more livelists to delete */
2469 		VERIFY0(zap_remove(mos, DMU_POOL_DIRECTORY_OBJECT,
2470 		    DMU_POOL_DELETED_CLONES, tx));
2471 		VERIFY0(zap_destroy(mos, zap_obj, tx));
2472 		spa->spa_livelists_to_delete = 0;
2473 		spa_notify_waiters(spa);
2474 	}
2475 }
2476 
2477 /*
2478  * Load in the value for the livelist to be removed and open it. Then,
2479  * load its first sublist and determine which block pointers should actually
2480  * be freed. Then, call a synctask which performs the actual frees and updates
2481  * the pool-wide livelist data.
2482  */
2483 /* ARGSUSED */
2484 static void
2485 spa_livelist_delete_cb(void *arg, zthr_t *z)
2486 {
2487 	spa_t *spa = arg;
2488 	uint64_t ll_obj = 0, count;
2489 	objset_t *mos = spa->spa_meta_objset;
2490 	uint64_t zap_obj = spa->spa_livelists_to_delete;
2491 	/*
2492 	 * Determine the next livelist to delete. This function should only
2493 	 * be called if there is at least one deleted clone.
2494 	 */
2495 	VERIFY0(dsl_get_next_livelist_obj(mos, zap_obj, &ll_obj));
2496 	VERIFY0(zap_count(mos, ll_obj, &count));
2497 	if (count > 0) {
2498 		dsl_deadlist_t *ll;
2499 		dsl_deadlist_entry_t *dle;
2500 		bplist_t to_free;
2501 		ll = kmem_zalloc(sizeof (dsl_deadlist_t), KM_SLEEP);
2502 		dsl_deadlist_open(ll, mos, ll_obj);
2503 		dle = dsl_deadlist_first(ll);
2504 		ASSERT3P(dle, !=, NULL);
2505 		bplist_create(&to_free);
2506 		int err = dsl_process_sub_livelist(&dle->dle_bpobj, &to_free,
2507 		    z, NULL);
2508 		if (err == 0) {
2509 			sublist_delete_arg_t sync_arg = {
2510 			    .spa = spa,
2511 			    .ll = ll,
2512 			    .key = dle->dle_mintxg,
2513 			    .to_free = &to_free
2514 			};
2515 			zfs_dbgmsg("deleting sublist (id %llu) from"
2516 			    " livelist %llu, %d remaining",
2517 			    dle->dle_bpobj.bpo_object, ll_obj, count - 1);
2518 			VERIFY0(dsl_sync_task(spa_name(spa), NULL,
2519 			    sublist_delete_sync, &sync_arg, 0,
2520 			    ZFS_SPACE_CHECK_DESTROY));
2521 		} else {
2522 			VERIFY3U(err, ==, EINTR);
2523 		}
2524 		bplist_clear(&to_free);
2525 		bplist_destroy(&to_free);
2526 		dsl_deadlist_close(ll);
2527 		kmem_free(ll, sizeof (dsl_deadlist_t));
2528 	} else {
2529 		livelist_delete_arg_t sync_arg = {
2530 		    .spa = spa,
2531 		    .ll_obj = ll_obj,
2532 		    .zap_obj = zap_obj
2533 		};
2534 		zfs_dbgmsg("deletion of livelist %llu completed", ll_obj);
2535 		VERIFY0(dsl_sync_task(spa_name(spa), NULL, livelist_delete_sync,
2536 		    &sync_arg, 0, ZFS_SPACE_CHECK_DESTROY));
2537 	}
2538 }
2539 
2540 static void
2541 spa_start_livelist_destroy_thread(spa_t *spa)
2542 {
2543 	ASSERT3P(spa->spa_livelist_delete_zthr, ==, NULL);
2544 	spa->spa_livelist_delete_zthr =
2545 	    zthr_create("z_livelist_destroy",
2546 	    spa_livelist_delete_cb_check, spa_livelist_delete_cb, spa);
2547 }
2548 
2549 typedef struct livelist_new_arg {
2550 	bplist_t *allocs;
2551 	bplist_t *frees;
2552 } livelist_new_arg_t;
2553 
2554 static int
2555 livelist_track_new_cb(void *arg, const blkptr_t *bp, boolean_t bp_freed,
2556     dmu_tx_t *tx)
2557 {
2558 	ASSERT(tx == NULL);
2559 	livelist_new_arg_t *lna = arg;
2560 	if (bp_freed) {
2561 		bplist_append(lna->frees, bp);
2562 	} else {
2563 		bplist_append(lna->allocs, bp);
2564 		zfs_livelist_condense_new_alloc++;
2565 	}
2566 	return (0);
2567 }
2568 
2569 typedef struct livelist_condense_arg {
2570 	spa_t *spa;
2571 	bplist_t to_keep;
2572 	uint64_t first_size;
2573 	uint64_t next_size;
2574 } livelist_condense_arg_t;
2575 
2576 static void
2577 spa_livelist_condense_sync(void *arg, dmu_tx_t *tx)
2578 {
2579 	livelist_condense_arg_t *lca = arg;
2580 	spa_t *spa = lca->spa;
2581 	bplist_t new_frees;
2582 	dsl_dataset_t *ds = spa->spa_to_condense.ds;
2583 
2584 	/* Have we been cancelled? */
2585 	if (spa->spa_to_condense.cancelled) {
2586 		zfs_livelist_condense_sync_cancel++;
2587 		goto out;
2588 	}
2589 
2590 	dsl_deadlist_entry_t *first = spa->spa_to_condense.first;
2591 	dsl_deadlist_entry_t *next = spa->spa_to_condense.next;
2592 	dsl_deadlist_t *ll = &ds->ds_dir->dd_livelist;
2593 
2594 	/*
2595 	 * It's possible that the livelist was changed while the zthr was
2596 	 * running. Therefore, we need to check for new blkptrs in the two
2597 	 * entries being condensed and continue to track them in the livelist.
2598 	 * Because of the way we handle remapped blkptrs (see dbuf_remap_impl),
2599 	 * it's possible that the newly added blkptrs are FREEs or ALLOCs so
2600 	 * we need to sort them into two different bplists.
2601 	 */
2602 	uint64_t first_obj = first->dle_bpobj.bpo_object;
2603 	uint64_t next_obj = next->dle_bpobj.bpo_object;
2604 	uint64_t cur_first_size = first->dle_bpobj.bpo_phys->bpo_num_blkptrs;
2605 	uint64_t cur_next_size = next->dle_bpobj.bpo_phys->bpo_num_blkptrs;
2606 
2607 	bplist_create(&new_frees);
2608 	livelist_new_arg_t new_bps = {
2609 	    .allocs = &lca->to_keep,
2610 	    .frees = &new_frees,
2611 	};
2612 
2613 	if (cur_first_size > lca->first_size) {
2614 		VERIFY0(livelist_bpobj_iterate_from_nofree(&first->dle_bpobj,
2615 		    livelist_track_new_cb, &new_bps, lca->first_size));
2616 	}
2617 	if (cur_next_size > lca->next_size) {
2618 		VERIFY0(livelist_bpobj_iterate_from_nofree(&next->dle_bpobj,
2619 		    livelist_track_new_cb, &new_bps, lca->next_size));
2620 	}
2621 
2622 	dsl_deadlist_clear_entry(first, ll, tx);
2623 	ASSERT(bpobj_is_empty(&first->dle_bpobj));
2624 	dsl_deadlist_remove_entry(ll, next->dle_mintxg, tx);
2625 
2626 	bplist_iterate(&lca->to_keep, dsl_deadlist_insert_alloc_cb, ll, tx);
2627 	bplist_iterate(&new_frees, dsl_deadlist_insert_free_cb, ll, tx);
2628 	bplist_destroy(&new_frees);
2629 
2630 	char dsname[ZFS_MAX_DATASET_NAME_LEN];
2631 	dsl_dataset_name(ds, dsname);
2632 	zfs_dbgmsg("txg %llu condensing livelist of %s (id %llu), bpobj %llu "
2633 	    "(%llu blkptrs) and bpobj %llu (%llu blkptrs) -> bpobj %llu "
2634 	    "(%llu blkptrs)", tx->tx_txg, dsname, ds->ds_object, first_obj,
2635 	    cur_first_size, next_obj, cur_next_size,
2636 	    first->dle_bpobj.bpo_object,
2637 	    first->dle_bpobj.bpo_phys->bpo_num_blkptrs);
2638 out:
2639 	dmu_buf_rele(ds->ds_dbuf, spa);
2640 	spa->spa_to_condense.ds = NULL;
2641 	bplist_clear(&lca->to_keep);
2642 	bplist_destroy(&lca->to_keep);
2643 	kmem_free(lca, sizeof (livelist_condense_arg_t));
2644 	spa->spa_to_condense.syncing = B_FALSE;
2645 }
2646 
2647 static void
2648 spa_livelist_condense_cb(void *arg, zthr_t *t)
2649 {
2650 	while (zfs_livelist_condense_zthr_pause &&
2651 	    !(zthr_has_waiters(t) || zthr_iscancelled(t)))
2652 		delay(1);
2653 
2654 	spa_t *spa = arg;
2655 	dsl_deadlist_entry_t *first = spa->spa_to_condense.first;
2656 	dsl_deadlist_entry_t *next = spa->spa_to_condense.next;
2657 	uint64_t first_size, next_size;
2658 
2659 	livelist_condense_arg_t *lca =
2660 	    kmem_alloc(sizeof (livelist_condense_arg_t), KM_SLEEP);
2661 	bplist_create(&lca->to_keep);
2662 
2663 	/*
2664 	 * Process the livelists (matching FREEs and ALLOCs) in open context
2665 	 * so we have minimal work in syncing context to condense.
2666 	 *
2667 	 * We save bpobj sizes (first_size and next_size) to use later in
2668 	 * syncing context to determine if entries were added to these sublists
2669 	 * while in open context. This is possible because the clone is still
2670 	 * active and open for normal writes and we want to make sure the new,
2671 	 * unprocessed blockpointers are inserted into the livelist normally.
2672 	 *
2673 	 * Note that dsl_process_sub_livelist() both stores the size number of
2674 	 * blockpointers and iterates over them while the bpobj's lock held, so
2675 	 * the sizes returned to us are consistent which what was actually
2676 	 * processed.
2677 	 */
2678 	int err = dsl_process_sub_livelist(&first->dle_bpobj, &lca->to_keep, t,
2679 	    &first_size);
2680 	if (err == 0)
2681 		err = dsl_process_sub_livelist(&next->dle_bpobj, &lca->to_keep,
2682 		    t, &next_size);
2683 
2684 	if (err == 0) {
2685 		while (zfs_livelist_condense_sync_pause &&
2686 		    !(zthr_has_waiters(t) || zthr_iscancelled(t)))
2687 			delay(1);
2688 
2689 		dmu_tx_t *tx = dmu_tx_create_dd(spa_get_dsl(spa)->dp_mos_dir);
2690 		dmu_tx_mark_netfree(tx);
2691 		dmu_tx_hold_space(tx, 1);
2692 		err = dmu_tx_assign(tx, TXG_NOWAIT | TXG_NOTHROTTLE);
2693 		if (err == 0) {
2694 			/*
2695 			 * Prevent the condense zthr restarting before
2696 			 * the synctask completes.
2697 			 */
2698 			spa->spa_to_condense.syncing = B_TRUE;
2699 			lca->spa = spa;
2700 			lca->first_size = first_size;
2701 			lca->next_size = next_size;
2702 			dsl_sync_task_nowait(spa_get_dsl(spa),
2703 			    spa_livelist_condense_sync, lca, tx);
2704 			dmu_tx_commit(tx);
2705 			return;
2706 		}
2707 	}
2708 	/*
2709 	 * Condensing can not continue: either it was externally stopped or
2710 	 * we were unable to assign to a tx because the pool has run out of
2711 	 * space. In the second case, we'll just end up trying to condense
2712 	 * again in a later txg.
2713 	 */
2714 	ASSERT(err != 0);
2715 	bplist_clear(&lca->to_keep);
2716 	bplist_destroy(&lca->to_keep);
2717 	kmem_free(lca, sizeof (livelist_condense_arg_t));
2718 	dmu_buf_rele(spa->spa_to_condense.ds->ds_dbuf, spa);
2719 	spa->spa_to_condense.ds = NULL;
2720 	if (err == EINTR)
2721 		zfs_livelist_condense_zthr_cancel++;
2722 }
2723 
2724 /* ARGSUSED */
2725 /*
2726  * Check that there is something to condense but that a condense is not
2727  * already in progress and that condensing has not been cancelled.
2728  */
2729 static boolean_t
2730 spa_livelist_condense_cb_check(void *arg, zthr_t *z)
2731 {
2732 	spa_t *spa = arg;
2733 	if ((spa->spa_to_condense.ds != NULL) &&
2734 	    (spa->spa_to_condense.syncing == B_FALSE) &&
2735 	    (spa->spa_to_condense.cancelled == B_FALSE)) {
2736 		return (B_TRUE);
2737 	}
2738 	return (B_FALSE);
2739 }
2740 
2741 static void
2742 spa_start_livelist_condensing_thread(spa_t *spa)
2743 {
2744 	spa->spa_to_condense.ds = NULL;
2745 	spa->spa_to_condense.first = NULL;
2746 	spa->spa_to_condense.next = NULL;
2747 	spa->spa_to_condense.syncing = B_FALSE;
2748 	spa->spa_to_condense.cancelled = B_FALSE;
2749 
2750 	ASSERT3P(spa->spa_livelist_condense_zthr, ==, NULL);
2751 	spa->spa_livelist_condense_zthr =
2752 	    zthr_create("z_livelist_condense",
2753 	    spa_livelist_condense_cb_check,
2754 	    spa_livelist_condense_cb, spa);
2755 }
2756 
2757 static void
2758 spa_spawn_aux_threads(spa_t *spa)
2759 {
2760 	ASSERT(spa_writeable(spa));
2761 
2762 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
2763 
2764 	spa_start_indirect_condensing_thread(spa);
2765 	spa_start_livelist_destroy_thread(spa);
2766 	spa_start_livelist_condensing_thread(spa);
2767 
2768 	ASSERT3P(spa->spa_checkpoint_discard_zthr, ==, NULL);
2769 	spa->spa_checkpoint_discard_zthr =
2770 	    zthr_create("z_checkpoint_discard",
2771 	    spa_checkpoint_discard_thread_check,
2772 	    spa_checkpoint_discard_thread, spa);
2773 }
2774 
2775 /*
2776  * Fix up config after a partly-completed split.  This is done with the
2777  * ZPOOL_CONFIG_SPLIT nvlist.  Both the splitting pool and the split-off
2778  * pool have that entry in their config, but only the splitting one contains
2779  * a list of all the guids of the vdevs that are being split off.
2780  *
2781  * This function determines what to do with that list: either rejoin
2782  * all the disks to the pool, or complete the splitting process.  To attempt
2783  * the rejoin, each disk that is offlined is marked online again, and
2784  * we do a reopen() call.  If the vdev label for every disk that was
2785  * marked online indicates it was successfully split off (VDEV_AUX_SPLIT_POOL)
2786  * then we call vdev_split() on each disk, and complete the split.
2787  *
2788  * Otherwise we leave the config alone, with all the vdevs in place in
2789  * the original pool.
2790  */
2791 static void
2792 spa_try_repair(spa_t *spa, nvlist_t *config)
2793 {
2794 	uint_t extracted;
2795 	uint64_t *glist;
2796 	uint_t i, gcount;
2797 	nvlist_t *nvl;
2798 	vdev_t **vd;
2799 	boolean_t attempt_reopen;
2800 
2801 	if (nvlist_lookup_nvlist(config, ZPOOL_CONFIG_SPLIT, &nvl) != 0)
2802 		return;
2803 
2804 	/* check that the config is complete */
2805 	if (nvlist_lookup_uint64_array(nvl, ZPOOL_CONFIG_SPLIT_LIST,
2806 	    &glist, &gcount) != 0)
2807 		return;
2808 
2809 	vd = kmem_zalloc(gcount * sizeof (vdev_t *), KM_SLEEP);
2810 
2811 	/* attempt to online all the vdevs & validate */
2812 	attempt_reopen = B_TRUE;
2813 	for (i = 0; i < gcount; i++) {
2814 		if (glist[i] == 0)	/* vdev is hole */
2815 			continue;
2816 
2817 		vd[i] = spa_lookup_by_guid(spa, glist[i], B_FALSE);
2818 		if (vd[i] == NULL) {
2819 			/*
2820 			 * Don't bother attempting to reopen the disks;
2821 			 * just do the split.
2822 			 */
2823 			attempt_reopen = B_FALSE;
2824 		} else {
2825 			/* attempt to re-online it */
2826 			vd[i]->vdev_offline = B_FALSE;
2827 		}
2828 	}
2829 
2830 	if (attempt_reopen) {
2831 		vdev_reopen(spa->spa_root_vdev);
2832 
2833 		/* check each device to see what state it's in */
2834 		for (extracted = 0, i = 0; i < gcount; i++) {
2835 			if (vd[i] != NULL &&
2836 			    vd[i]->vdev_stat.vs_aux != VDEV_AUX_SPLIT_POOL)
2837 				break;
2838 			++extracted;
2839 		}
2840 	}
2841 
2842 	/*
2843 	 * If every disk has been moved to the new pool, or if we never
2844 	 * even attempted to look at them, then we split them off for
2845 	 * good.
2846 	 */
2847 	if (!attempt_reopen || gcount == extracted) {
2848 		for (i = 0; i < gcount; i++)
2849 			if (vd[i] != NULL)
2850 				vdev_split(vd[i]);
2851 		vdev_reopen(spa->spa_root_vdev);
2852 	}
2853 
2854 	kmem_free(vd, gcount * sizeof (vdev_t *));
2855 }
2856 
2857 static int
2858 spa_load(spa_t *spa, spa_load_state_t state, spa_import_type_t type)
2859 {
2860 	char *ereport = FM_EREPORT_ZFS_POOL;
2861 	int error;
2862 
2863 	spa->spa_load_state = state;
2864 	(void) spa_import_progress_set_state(spa_guid(spa),
2865 	    spa_load_state(spa));
2866 
2867 	gethrestime(&spa->spa_loaded_ts);
2868 	error = spa_load_impl(spa, type, &ereport);
2869 
2870 	/*
2871 	 * Don't count references from objsets that are already closed
2872 	 * and are making their way through the eviction process.
2873 	 */
2874 	spa_evicting_os_wait(spa);
2875 	spa->spa_minref = zfs_refcount_count(&spa->spa_refcount);
2876 	if (error) {
2877 		if (error != EEXIST) {
2878 			spa->spa_loaded_ts.tv_sec = 0;
2879 			spa->spa_loaded_ts.tv_nsec = 0;
2880 		}
2881 		if (error != EBADF) {
2882 			(void) zfs_ereport_post(ereport, spa,
2883 			    NULL, NULL, NULL, 0);
2884 		}
2885 	}
2886 	spa->spa_load_state = error ? SPA_LOAD_ERROR : SPA_LOAD_NONE;
2887 	spa->spa_ena = 0;
2888 
2889 	(void) spa_import_progress_set_state(spa_guid(spa),
2890 	    spa_load_state(spa));
2891 
2892 	return (error);
2893 }
2894 
2895 #ifdef ZFS_DEBUG
2896 /*
2897  * Count the number of per-vdev ZAPs associated with all of the vdevs in the
2898  * vdev tree rooted in the given vd, and ensure that each ZAP is present in the
2899  * spa's per-vdev ZAP list.
2900  */
2901 static uint64_t
2902 vdev_count_verify_zaps(vdev_t *vd)
2903 {
2904 	spa_t *spa = vd->vdev_spa;
2905 	uint64_t total = 0;
2906 
2907 	if (vd->vdev_top_zap != 0) {
2908 		total++;
2909 		ASSERT0(zap_lookup_int(spa->spa_meta_objset,
2910 		    spa->spa_all_vdev_zaps, vd->vdev_top_zap));
2911 	}
2912 	if (vd->vdev_leaf_zap != 0) {
2913 		total++;
2914 		ASSERT0(zap_lookup_int(spa->spa_meta_objset,
2915 		    spa->spa_all_vdev_zaps, vd->vdev_leaf_zap));
2916 	}
2917 
2918 	for (uint64_t i = 0; i < vd->vdev_children; i++) {
2919 		total += vdev_count_verify_zaps(vd->vdev_child[i]);
2920 	}
2921 
2922 	return (total);
2923 }
2924 #endif
2925 
2926 /*
2927  * Determine whether the activity check is required.
2928  */
2929 static boolean_t
2930 spa_activity_check_required(spa_t *spa, uberblock_t *ub, nvlist_t *label,
2931     nvlist_t *config)
2932 {
2933 	uint64_t state = 0;
2934 	uint64_t hostid = 0;
2935 	uint64_t tryconfig_txg = 0;
2936 	uint64_t tryconfig_timestamp = 0;
2937 	uint16_t tryconfig_mmp_seq = 0;
2938 	nvlist_t *nvinfo;
2939 
2940 	if (nvlist_exists(config, ZPOOL_CONFIG_LOAD_INFO)) {
2941 		nvinfo = fnvlist_lookup_nvlist(config, ZPOOL_CONFIG_LOAD_INFO);
2942 		(void) nvlist_lookup_uint64(nvinfo, ZPOOL_CONFIG_MMP_TXG,
2943 		    &tryconfig_txg);
2944 		(void) nvlist_lookup_uint64(config, ZPOOL_CONFIG_TIMESTAMP,
2945 		    &tryconfig_timestamp);
2946 		(void) nvlist_lookup_uint16(nvinfo, ZPOOL_CONFIG_MMP_SEQ,
2947 		    &tryconfig_mmp_seq);
2948 	}
2949 
2950 	(void) nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_STATE, &state);
2951 
2952 	/*
2953 	 * Disable the MMP activity check - This is used by zdb which
2954 	 * is intended to be used on potentially active pools.
2955 	 */
2956 	if (spa->spa_import_flags & ZFS_IMPORT_SKIP_MMP)
2957 		return (B_FALSE);
2958 
2959 	/*
2960 	 * Skip the activity check when the MMP feature is disabled.
2961 	 */
2962 	if (ub->ub_mmp_magic == MMP_MAGIC && ub->ub_mmp_delay == 0)
2963 		return (B_FALSE);
2964 
2965 	/*
2966 	 * If the tryconfig_ values are nonzero, they are the results of an
2967 	 * earlier tryimport.  If they all match the uberblock we just found,
2968 	 * then the pool has not changed and we return false so we do not test
2969 	 * a second time.
2970 	 */
2971 	if (tryconfig_txg && tryconfig_txg == ub->ub_txg &&
2972 	    tryconfig_timestamp && tryconfig_timestamp == ub->ub_timestamp &&
2973 	    tryconfig_mmp_seq && tryconfig_mmp_seq ==
2974 	    (MMP_SEQ_VALID(ub) ? MMP_SEQ(ub) : 0))
2975 		return (B_FALSE);
2976 
2977 	/*
2978 	 * Allow the activity check to be skipped when importing the pool
2979 	 * on the same host which last imported it.  Since the hostid from
2980 	 * configuration may be stale use the one read from the label.
2981 	 */
2982 	if (nvlist_exists(label, ZPOOL_CONFIG_HOSTID))
2983 		hostid = fnvlist_lookup_uint64(label, ZPOOL_CONFIG_HOSTID);
2984 
2985 	if (hostid == spa_get_hostid(spa))
2986 		return (B_FALSE);
2987 
2988 	/*
2989 	 * Skip the activity test when the pool was cleanly exported.
2990 	 */
2991 	if (state != POOL_STATE_ACTIVE)
2992 		return (B_FALSE);
2993 
2994 	return (B_TRUE);
2995 }
2996 
2997 /*
2998  * Nanoseconds the activity check must watch for changes on-disk.
2999  */
3000 static uint64_t
3001 spa_activity_check_duration(spa_t *spa, uberblock_t *ub)
3002 {
3003 	uint64_t import_intervals = MAX(zfs_multihost_import_intervals, 1);
3004 	uint64_t multihost_interval = MSEC2NSEC(
3005 	    MMP_INTERVAL_OK(zfs_multihost_interval));
3006 	uint64_t import_delay = MAX(NANOSEC, import_intervals *
3007 	    multihost_interval);
3008 
3009 	/*
3010 	 * Local tunables determine a minimum duration except for the case
3011 	 * where we know when the remote host will suspend the pool if MMP
3012 	 * writes do not land.
3013 	 *
3014 	 * See Big Theory comment at the top of mmp.c for the reasoning behind
3015 	 * these cases and times.
3016 	 */
3017 
3018 	ASSERT(MMP_IMPORT_SAFETY_FACTOR >= 100);
3019 
3020 	if (MMP_INTERVAL_VALID(ub) && MMP_FAIL_INT_VALID(ub) &&
3021 	    MMP_FAIL_INT(ub) > 0) {
3022 
3023 		/* MMP on remote host will suspend pool after failed writes */
3024 		import_delay = MMP_FAIL_INT(ub) * MSEC2NSEC(MMP_INTERVAL(ub)) *
3025 		    MMP_IMPORT_SAFETY_FACTOR / 100;
3026 
3027 		zfs_dbgmsg("fail_intvals>0 import_delay=%llu ub_mmp "
3028 		    "mmp_fails=%llu ub_mmp mmp_interval=%llu "
3029 		    "import_intervals=%u", import_delay, MMP_FAIL_INT(ub),
3030 		    MMP_INTERVAL(ub), import_intervals);
3031 
3032 	} else if (MMP_INTERVAL_VALID(ub) && MMP_FAIL_INT_VALID(ub) &&
3033 	    MMP_FAIL_INT(ub) == 0) {
3034 
3035 		/* MMP on remote host will never suspend pool */
3036 		import_delay = MAX(import_delay, (MSEC2NSEC(MMP_INTERVAL(ub)) +
3037 		    ub->ub_mmp_delay) * import_intervals);
3038 
3039 		zfs_dbgmsg("fail_intvals=0 import_delay=%llu ub_mmp "
3040 		    "mmp_interval=%llu ub_mmp_delay=%llu "
3041 		    "import_intervals=%u", import_delay, MMP_INTERVAL(ub),
3042 		    ub->ub_mmp_delay, import_intervals);
3043 
3044 	} else if (MMP_VALID(ub)) {
3045 		/*
3046 		 * zfs-0.7 compatibility case
3047 		 */
3048 
3049 		import_delay = MAX(import_delay, (multihost_interval +
3050 		    ub->ub_mmp_delay) * import_intervals);
3051 
3052 		zfs_dbgmsg("import_delay=%llu ub_mmp_delay=%llu "
3053 		    "import_intervals=%u leaves=%u", import_delay,
3054 		    ub->ub_mmp_delay, import_intervals,
3055 		    vdev_count_leaves(spa));
3056 	} else {
3057 		/* Using local tunings is the only reasonable option */
3058 		zfs_dbgmsg("pool last imported on non-MMP aware "
3059 		    "host using import_delay=%llu multihost_interval=%llu "
3060 		    "import_intervals=%u", import_delay, multihost_interval,
3061 		    import_intervals);
3062 	}
3063 
3064 	return (import_delay);
3065 }
3066 
3067 /*
3068  * Perform the import activity check.  If the user canceled the import or
3069  * we detected activity then fail.
3070  */
3071 static int
3072 spa_activity_check(spa_t *spa, uberblock_t *ub, nvlist_t *config)
3073 {
3074 	uint64_t txg = ub->ub_txg;
3075 	uint64_t timestamp = ub->ub_timestamp;
3076 	uint64_t mmp_config = ub->ub_mmp_config;
3077 	uint16_t mmp_seq = MMP_SEQ_VALID(ub) ? MMP_SEQ(ub) : 0;
3078 	uint64_t import_delay;
3079 	hrtime_t import_expire;
3080 	nvlist_t *mmp_label = NULL;
3081 	vdev_t *rvd = spa->spa_root_vdev;
3082 	kcondvar_t cv;
3083 	kmutex_t mtx;
3084 	int error = 0;
3085 
3086 	cv_init(&cv, NULL, CV_DEFAULT, NULL);
3087 	mutex_init(&mtx, NULL, MUTEX_DEFAULT, NULL);
3088 	mutex_enter(&mtx);
3089 
3090 	/*
3091 	 * If ZPOOL_CONFIG_MMP_TXG is present an activity check was performed
3092 	 * during the earlier tryimport.  If the txg recorded there is 0 then
3093 	 * the pool is known to be active on another host.
3094 	 *
3095 	 * Otherwise, the pool might be in use on another host.  Check for
3096 	 * changes in the uberblocks on disk if necessary.
3097 	 */
3098 	if (nvlist_exists(config, ZPOOL_CONFIG_LOAD_INFO)) {
3099 		nvlist_t *nvinfo = fnvlist_lookup_nvlist(config,
3100 		    ZPOOL_CONFIG_LOAD_INFO);
3101 
3102 		if (nvlist_exists(nvinfo, ZPOOL_CONFIG_MMP_TXG) &&
3103 		    fnvlist_lookup_uint64(nvinfo, ZPOOL_CONFIG_MMP_TXG) == 0) {
3104 			vdev_uberblock_load(rvd, ub, &mmp_label);
3105 			error = SET_ERROR(EREMOTEIO);
3106 			goto out;
3107 		}
3108 	}
3109 
3110 	import_delay = spa_activity_check_duration(spa, ub);
3111 
3112 	/* Add a small random factor in case of simultaneous imports (0-25%) */
3113 	import_delay += import_delay * spa_get_random(250) / 1000;
3114 
3115 	import_expire = gethrtime() + import_delay;
3116 
3117 	while (gethrtime() < import_expire) {
3118 		(void) spa_import_progress_set_mmp_check(spa_guid(spa),
3119 		    NSEC2SEC(import_expire - gethrtime()));
3120 
3121 		vdev_uberblock_load(rvd, ub, &mmp_label);
3122 
3123 		if (txg != ub->ub_txg || timestamp != ub->ub_timestamp ||
3124 		    mmp_seq != (MMP_SEQ_VALID(ub) ? MMP_SEQ(ub) : 0)) {
3125 			zfs_dbgmsg("multihost activity detected "
3126 			    "txg %llu ub_txg  %llu "
3127 			    "timestamp %llu ub_timestamp  %llu "
3128 			    "mmp_config %#llx ub_mmp_config %#llx",
3129 			    txg, ub->ub_txg, timestamp, ub->ub_timestamp,
3130 			    mmp_config, ub->ub_mmp_config);
3131 
3132 			error = SET_ERROR(EREMOTEIO);
3133 			break;
3134 		}
3135 
3136 		if (mmp_label) {
3137 			nvlist_free(mmp_label);
3138 			mmp_label = NULL;
3139 		}
3140 
3141 		error = cv_timedwait_sig(&cv, &mtx, ddi_get_lbolt() + hz);
3142 		if (error != -1) {
3143 			error = SET_ERROR(EINTR);
3144 			break;
3145 		}
3146 		error = 0;
3147 	}
3148 
3149 out:
3150 	mutex_exit(&mtx);
3151 	mutex_destroy(&mtx);
3152 	cv_destroy(&cv);
3153 
3154 	/*
3155 	 * If the pool is determined to be active store the status in the
3156 	 * spa->spa_load_info nvlist.  If the remote hostname or hostid are
3157 	 * available from configuration read from disk store them as well.
3158 	 * This allows 'zpool import' to generate a more useful message.
3159 	 *
3160 	 * ZPOOL_CONFIG_MMP_STATE    - observed pool status (mandatory)
3161 	 * ZPOOL_CONFIG_MMP_HOSTNAME - hostname from the active pool
3162 	 * ZPOOL_CONFIG_MMP_HOSTID   - hostid from the active pool
3163 	 */
3164 	if (error == EREMOTEIO) {
3165 		char *hostname = "<unknown>";
3166 		uint64_t hostid = 0;
3167 
3168 		if (mmp_label) {
3169 			if (nvlist_exists(mmp_label, ZPOOL_CONFIG_HOSTNAME)) {
3170 				hostname = fnvlist_lookup_string(mmp_label,
3171 				    ZPOOL_CONFIG_HOSTNAME);
3172 				fnvlist_add_string(spa->spa_load_info,
3173 				    ZPOOL_CONFIG_MMP_HOSTNAME, hostname);
3174 			}
3175 
3176 			if (nvlist_exists(mmp_label, ZPOOL_CONFIG_HOSTID)) {
3177 				hostid = fnvlist_lookup_uint64(mmp_label,
3178 				    ZPOOL_CONFIG_HOSTID);
3179 				fnvlist_add_uint64(spa->spa_load_info,
3180 				    ZPOOL_CONFIG_MMP_HOSTID, hostid);
3181 			}
3182 		}
3183 
3184 		fnvlist_add_uint64(spa->spa_load_info,
3185 		    ZPOOL_CONFIG_MMP_STATE, MMP_STATE_ACTIVE);
3186 		fnvlist_add_uint64(spa->spa_load_info,
3187 		    ZPOOL_CONFIG_MMP_TXG, 0);
3188 
3189 		error = spa_vdev_err(rvd, VDEV_AUX_ACTIVE, EREMOTEIO);
3190 	}
3191 
3192 	if (mmp_label)
3193 		nvlist_free(mmp_label);
3194 
3195 	return (error);
3196 }
3197 
3198 static int
3199 spa_verify_host(spa_t *spa, nvlist_t *mos_config)
3200 {
3201 	uint64_t hostid;
3202 	char *hostname;
3203 	uint64_t myhostid = 0;
3204 
3205 	if (!spa_is_root(spa) && nvlist_lookup_uint64(mos_config,
3206 	    ZPOOL_CONFIG_HOSTID, &hostid) == 0) {
3207 		hostname = fnvlist_lookup_string(mos_config,
3208 		    ZPOOL_CONFIG_HOSTNAME);
3209 
3210 		myhostid = zone_get_hostid(NULL);
3211 
3212 		if (hostid != 0 && myhostid != 0 && hostid != myhostid) {
3213 			cmn_err(CE_WARN, "pool '%s' could not be "
3214 			    "loaded as it was last accessed by "
3215 			    "another system (host: %s hostid: 0x%llx). "
3216 			    "See: https://openzfs.github.io/openzfs-docs/msg/"
3217 			    "ZFS-8000-EY",
3218 			    spa_name(spa), hostname, (u_longlong_t)hostid);
3219 			spa_load_failed(spa, "hostid verification failed: pool "
3220 			    "last accessed by host: %s (hostid: 0x%llx)",
3221 			    hostname, (u_longlong_t)hostid);
3222 			return (SET_ERROR(EBADF));
3223 		}
3224 	}
3225 
3226 	return (0);
3227 }
3228 
3229 static int
3230 spa_ld_parse_config(spa_t *spa, spa_import_type_t type)
3231 {
3232 	int error = 0;
3233 	nvlist_t *nvtree, *nvl, *config = spa->spa_config;
3234 	int parse;
3235 	vdev_t *rvd;
3236 	uint64_t pool_guid;
3237 	char *comment;
3238 
3239 	/*
3240 	 * Versioning wasn't explicitly added to the label until later, so if
3241 	 * it's not present treat it as the initial version.
3242 	 */
3243 	if (nvlist_lookup_uint64(config, ZPOOL_CONFIG_VERSION,
3244 	    &spa->spa_ubsync.ub_version) != 0)
3245 		spa->spa_ubsync.ub_version = SPA_VERSION_INITIAL;
3246 
3247 	if (nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_GUID, &pool_guid)) {
3248 		spa_load_failed(spa, "invalid config provided: '%s' missing",
3249 		    ZPOOL_CONFIG_POOL_GUID);
3250 		return (SET_ERROR(EINVAL));
3251 	}
3252 
3253 	/*
3254 	 * If we are doing an import, ensure that the pool is not already
3255 	 * imported by checking if its pool guid already exists in the
3256 	 * spa namespace.
3257 	 *
3258 	 * The only case that we allow an already imported pool to be
3259 	 * imported again, is when the pool is checkpointed and we want to
3260 	 * look at its checkpointed state from userland tools like zdb.
3261 	 */
3262 #ifdef _KERNEL
3263 	if ((spa->spa_load_state == SPA_LOAD_IMPORT ||
3264 	    spa->spa_load_state == SPA_LOAD_TRYIMPORT) &&
3265 	    spa_guid_exists(pool_guid, 0)) {
3266 #else
3267 	if ((spa->spa_load_state == SPA_LOAD_IMPORT ||
3268 	    spa->spa_load_state == SPA_LOAD_TRYIMPORT) &&
3269 	    spa_guid_exists(pool_guid, 0) &&
3270 	    !spa_importing_readonly_checkpoint(spa)) {
3271 #endif
3272 		spa_load_failed(spa, "a pool with guid %llu is already open",
3273 		    (u_longlong_t)pool_guid);
3274 		return (SET_ERROR(EEXIST));
3275 	}
3276 
3277 	spa->spa_config_guid = pool_guid;
3278 
3279 	nvlist_free(spa->spa_load_info);
3280 	spa->spa_load_info = fnvlist_alloc();
3281 
3282 	ASSERT(spa->spa_comment == NULL);
3283 	if (nvlist_lookup_string(config, ZPOOL_CONFIG_COMMENT, &comment) == 0)
3284 		spa->spa_comment = spa_strdup(comment);
3285 
3286 	(void) nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_TXG,
3287 	    &spa->spa_config_txg);
3288 
3289 	if (nvlist_lookup_nvlist(config, ZPOOL_CONFIG_SPLIT, &nvl) == 0)
3290 		spa->spa_config_splitting = fnvlist_dup(nvl);
3291 
3292 	if (nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE, &nvtree)) {
3293 		spa_load_failed(spa, "invalid config provided: '%s' missing",
3294 		    ZPOOL_CONFIG_VDEV_TREE);
3295 		return (SET_ERROR(EINVAL));
3296 	}
3297 
3298 	/*
3299 	 * Create "The Godfather" zio to hold all async IOs
3300 	 */
3301 	spa->spa_async_zio_root = kmem_alloc(max_ncpus * sizeof (void *),
3302 	    KM_SLEEP);
3303 	for (int i = 0; i < max_ncpus; i++) {
3304 		spa->spa_async_zio_root[i] = zio_root(spa, NULL, NULL,
3305 		    ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE |
3306 		    ZIO_FLAG_GODFATHER);
3307 	}
3308 
3309 	/*
3310 	 * Parse the configuration into a vdev tree.  We explicitly set the
3311 	 * value that will be returned by spa_version() since parsing the
3312 	 * configuration requires knowing the version number.
3313 	 */
3314 	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
3315 	parse = (type == SPA_IMPORT_EXISTING ?
3316 	    VDEV_ALLOC_LOAD : VDEV_ALLOC_SPLIT);
3317 	error = spa_config_parse(spa, &rvd, nvtree, NULL, 0, parse);
3318 	spa_config_exit(spa, SCL_ALL, FTAG);
3319 
3320 	if (error != 0) {
3321 		spa_load_failed(spa, "unable to parse config [error=%d]",
3322 		    error);
3323 		return (error);
3324 	}
3325 
3326 	ASSERT(spa->spa_root_vdev == rvd);
3327 	ASSERT3U(spa->spa_min_ashift, >=, SPA_MINBLOCKSHIFT);
3328 	ASSERT3U(spa->spa_max_ashift, <=, SPA_MAXBLOCKSHIFT);
3329 
3330 	if (type != SPA_IMPORT_ASSEMBLE) {
3331 		ASSERT(spa_guid(spa) == pool_guid);
3332 	}
3333 
3334 	return (0);
3335 }
3336 
3337 /*
3338  * Recursively open all vdevs in the vdev tree. This function is called twice:
3339  * first with the untrusted config, then with the trusted config.
3340  */
3341 static int
3342 spa_ld_open_vdevs(spa_t *spa)
3343 {
3344 	int error = 0;
3345 
3346 	/*
3347 	 * spa_missing_tvds_allowed defines how many top-level vdevs can be
3348 	 * missing/unopenable for the root vdev to be still considered openable.
3349 	 */
3350 	if (spa->spa_trust_config) {
3351 		spa->spa_missing_tvds_allowed = zfs_max_missing_tvds;
3352 	} else if (spa->spa_config_source == SPA_CONFIG_SRC_CACHEFILE) {
3353 		spa->spa_missing_tvds_allowed = zfs_max_missing_tvds_cachefile;
3354 	} else if (spa->spa_config_source == SPA_CONFIG_SRC_SCAN) {
3355 		spa->spa_missing_tvds_allowed = zfs_max_missing_tvds_scan;
3356 	} else {
3357 		spa->spa_missing_tvds_allowed = 0;
3358 	}
3359 
3360 	spa->spa_missing_tvds_allowed =
3361 	    MAX(zfs_max_missing_tvds, spa->spa_missing_tvds_allowed);
3362 
3363 	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
3364 	error = vdev_open(spa->spa_root_vdev);
3365 	spa_config_exit(spa, SCL_ALL, FTAG);
3366 
3367 	if (spa->spa_missing_tvds != 0) {
3368 		spa_load_note(spa, "vdev tree has %lld missing top-level "
3369 		    "vdevs.", (u_longlong_t)spa->spa_missing_tvds);
3370 		if (spa->spa_trust_config && (spa->spa_mode & SPA_MODE_WRITE)) {
3371 			/*
3372 			 * Although theoretically we could allow users to open
3373 			 * incomplete pools in RW mode, we'd need to add a lot
3374 			 * of extra logic (e.g. adjust pool space to account
3375 			 * for missing vdevs).
3376 			 * This limitation also prevents users from accidentally
3377 			 * opening the pool in RW mode during data recovery and
3378 			 * damaging it further.
3379 			 */
3380 			spa_load_note(spa, "pools with missing top-level "
3381 			    "vdevs can only be opened in read-only mode.");
3382 			error = SET_ERROR(ENXIO);
3383 		} else {
3384 			spa_load_note(spa, "current settings allow for maximum "
3385 			    "%lld missing top-level vdevs at this stage.",
3386 			    (u_longlong_t)spa->spa_missing_tvds_allowed);
3387 		}
3388 	}
3389 	if (error != 0) {
3390 		spa_load_failed(spa, "unable to open vdev tree [error=%d]",
3391 		    error);
3392 	}
3393 	if (spa->spa_missing_tvds != 0 || error != 0)
3394 		vdev_dbgmsg_print_tree(spa->spa_root_vdev, 2);
3395 
3396 	return (error);
3397 }
3398 
3399 /*
3400  * We need to validate the vdev labels against the configuration that
3401  * we have in hand. This function is called twice: first with an untrusted
3402  * config, then with a trusted config. The validation is more strict when the
3403  * config is trusted.
3404  */
3405 static int
3406 spa_ld_validate_vdevs(spa_t *spa)
3407 {
3408 	int error = 0;
3409 	vdev_t *rvd = spa->spa_root_vdev;
3410 
3411 	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
3412 	error = vdev_validate(rvd);
3413 	spa_config_exit(spa, SCL_ALL, FTAG);
3414 
3415 	if (error != 0) {
3416 		spa_load_failed(spa, "vdev_validate failed [error=%d]", error);
3417 		return (error);
3418 	}
3419 
3420 	if (rvd->vdev_state <= VDEV_STATE_CANT_OPEN) {
3421 		spa_load_failed(spa, "cannot open vdev tree after invalidating "
3422 		    "some vdevs");
3423 		vdev_dbgmsg_print_tree(rvd, 2);
3424 		return (SET_ERROR(ENXIO));
3425 	}
3426 
3427 	return (0);
3428 }
3429 
3430 static void
3431 spa_ld_select_uberblock_done(spa_t *spa, uberblock_t *ub)
3432 {
3433 	spa->spa_state = POOL_STATE_ACTIVE;
3434 	spa->spa_ubsync = spa->spa_uberblock;
3435 	spa->spa_verify_min_txg = spa->spa_extreme_rewind ?
3436 	    TXG_INITIAL - 1 : spa_last_synced_txg(spa) - TXG_DEFER_SIZE - 1;
3437 	spa->spa_first_txg = spa->spa_last_ubsync_txg ?
3438 	    spa->spa_last_ubsync_txg : spa_last_synced_txg(spa) + 1;
3439 	spa->spa_claim_max_txg = spa->spa_first_txg;
3440 	spa->spa_prev_software_version = ub->ub_software_version;
3441 }
3442 
3443 static int
3444 spa_ld_select_uberblock(spa_t *spa, spa_import_type_t type)
3445 {
3446 	vdev_t *rvd = spa->spa_root_vdev;
3447 	nvlist_t *label;
3448 	uberblock_t *ub = &spa->spa_uberblock;
3449 	boolean_t activity_check = B_FALSE;
3450 
3451 	/*
3452 	 * If we are opening the checkpointed state of the pool by
3453 	 * rewinding to it, at this point we will have written the
3454 	 * checkpointed uberblock to the vdev labels, so searching
3455 	 * the labels will find the right uberblock.  However, if
3456 	 * we are opening the checkpointed state read-only, we have
3457 	 * not modified the labels. Therefore, we must ignore the
3458 	 * labels and continue using the spa_uberblock that was set
3459 	 * by spa_ld_checkpoint_rewind.
3460 	 *
3461 	 * Note that it would be fine to ignore the labels when
3462 	 * rewinding (opening writeable) as well. However, if we
3463 	 * crash just after writing the labels, we will end up
3464 	 * searching the labels. Doing so in the common case means
3465 	 * that this code path gets exercised normally, rather than
3466 	 * just in the edge case.
3467 	 */
3468 	if (ub->ub_checkpoint_txg != 0 &&
3469 	    spa_importing_readonly_checkpoint(spa)) {
3470 		spa_ld_select_uberblock_done(spa, ub);
3471 		return (0);
3472 	}
3473 
3474 	/*
3475 	 * Find the best uberblock.
3476 	 */
3477 	vdev_uberblock_load(rvd, ub, &label);
3478 
3479 	/*
3480 	 * If we weren't able to find a single valid uberblock, return failure.
3481 	 */
3482 	if (ub->ub_txg == 0) {
3483 		nvlist_free(label);
3484 		spa_load_failed(spa, "no valid uberblock found");
3485 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, ENXIO));
3486 	}
3487 
3488 	if (spa->spa_load_max_txg != UINT64_MAX) {
3489 		(void) spa_import_progress_set_max_txg(spa_guid(spa),
3490 		    (u_longlong_t)spa->spa_load_max_txg);
3491 	}
3492 	spa_load_note(spa, "using uberblock with txg=%llu",
3493 	    (u_longlong_t)ub->ub_txg);
3494 
3495 
3496 	/*
3497 	 * For pools which have the multihost property on determine if the
3498 	 * pool is truly inactive and can be safely imported.  Prevent
3499 	 * hosts which don't have a hostid set from importing the pool.
3500 	 */
3501 	activity_check = spa_activity_check_required(spa, ub, label,
3502 	    spa->spa_config);
3503 	if (activity_check) {
3504 		if (ub->ub_mmp_magic == MMP_MAGIC && ub->ub_mmp_delay &&
3505 		    spa_get_hostid(spa) == 0) {
3506 			nvlist_free(label);
3507 			fnvlist_add_uint64(spa->spa_load_info,
3508 			    ZPOOL_CONFIG_MMP_STATE, MMP_STATE_NO_HOSTID);
3509 			return (spa_vdev_err(rvd, VDEV_AUX_ACTIVE, EREMOTEIO));
3510 		}
3511 
3512 		int error = spa_activity_check(spa, ub, spa->spa_config);
3513 		if (error) {
3514 			nvlist_free(label);
3515 			return (error);
3516 		}
3517 
3518 		fnvlist_add_uint64(spa->spa_load_info,
3519 		    ZPOOL_CONFIG_MMP_STATE, MMP_STATE_INACTIVE);
3520 		fnvlist_add_uint64(spa->spa_load_info,
3521 		    ZPOOL_CONFIG_MMP_TXG, ub->ub_txg);
3522 		fnvlist_add_uint16(spa->spa_load_info,
3523 		    ZPOOL_CONFIG_MMP_SEQ,
3524 		    (MMP_SEQ_VALID(ub) ? MMP_SEQ(ub) : 0));
3525 	}
3526 
3527 	/*
3528 	 * If the pool has an unsupported version we can't open it.
3529 	 */
3530 	if (!SPA_VERSION_IS_SUPPORTED(ub->ub_version)) {
3531 		nvlist_free(label);
3532 		spa_load_failed(spa, "version %llu is not supported",
3533 		    (u_longlong_t)ub->ub_version);
3534 		return (spa_vdev_err(rvd, VDEV_AUX_VERSION_NEWER, ENOTSUP));
3535 	}
3536 
3537 	if (ub->ub_version >= SPA_VERSION_FEATURES) {
3538 		nvlist_t *features;
3539 
3540 		/*
3541 		 * If we weren't able to find what's necessary for reading the
3542 		 * MOS in the label, return failure.
3543 		 */
3544 		if (label == NULL) {
3545 			spa_load_failed(spa, "label config unavailable");
3546 			return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA,
3547 			    ENXIO));
3548 		}
3549 
3550 		if (nvlist_lookup_nvlist(label, ZPOOL_CONFIG_FEATURES_FOR_READ,
3551 		    &features) != 0) {
3552 			nvlist_free(label);
3553 			spa_load_failed(spa, "invalid label: '%s' missing",
3554 			    ZPOOL_CONFIG_FEATURES_FOR_READ);
3555 			return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA,
3556 			    ENXIO));
3557 		}
3558 
3559 		/*
3560 		 * Update our in-core representation with the definitive values
3561 		 * from the label.
3562 		 */
3563 		nvlist_free(spa->spa_label_features);
3564 		VERIFY(nvlist_dup(features, &spa->spa_label_features, 0) == 0);
3565 	}
3566 
3567 	nvlist_free(label);
3568 
3569 	/*
3570 	 * Look through entries in the label nvlist's features_for_read. If
3571 	 * there is a feature listed there which we don't understand then we
3572 	 * cannot open a pool.
3573 	 */
3574 	if (ub->ub_version >= SPA_VERSION_FEATURES) {
3575 		nvlist_t *unsup_feat;
3576 
3577 		VERIFY(nvlist_alloc(&unsup_feat, NV_UNIQUE_NAME, KM_SLEEP) ==
3578 		    0);
3579 
3580 		for (nvpair_t *nvp = nvlist_next_nvpair(spa->spa_label_features,
3581 		    NULL); nvp != NULL;
3582 		    nvp = nvlist_next_nvpair(spa->spa_label_features, nvp)) {
3583 			if (!zfeature_is_supported(nvpair_name(nvp))) {
3584 				VERIFY(nvlist_add_string(unsup_feat,
3585 				    nvpair_name(nvp), "") == 0);
3586 			}
3587 		}
3588 
3589 		if (!nvlist_empty(unsup_feat)) {
3590 			VERIFY(nvlist_add_nvlist(spa->spa_load_info,
3591 			    ZPOOL_CONFIG_UNSUP_FEAT, unsup_feat) == 0);
3592 			nvlist_free(unsup_feat);
3593 			spa_load_failed(spa, "some features are unsupported");
3594 			return (spa_vdev_err(rvd, VDEV_AUX_UNSUP_FEAT,
3595 			    ENOTSUP));
3596 		}
3597 
3598 		nvlist_free(unsup_feat);
3599 	}
3600 
3601 	if (type != SPA_IMPORT_ASSEMBLE && spa->spa_config_splitting) {
3602 		spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
3603 		spa_try_repair(spa, spa->spa_config);
3604 		spa_config_exit(spa, SCL_ALL, FTAG);
3605 		nvlist_free(spa->spa_config_splitting);
3606 		spa->spa_config_splitting = NULL;
3607 	}
3608 
3609 	/*
3610 	 * Initialize internal SPA structures.
3611 	 */
3612 	spa_ld_select_uberblock_done(spa, ub);
3613 
3614 	return (0);
3615 }
3616 
3617 static int
3618 spa_ld_open_rootbp(spa_t *spa)
3619 {
3620 	int error = 0;
3621 	vdev_t *rvd = spa->spa_root_vdev;
3622 
3623 	error = dsl_pool_init(spa, spa->spa_first_txg, &spa->spa_dsl_pool);
3624 	if (error != 0) {
3625 		spa_load_failed(spa, "unable to open rootbp in dsl_pool_init "
3626 		    "[error=%d]", error);
3627 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
3628 	}
3629 	spa->spa_meta_objset = spa->spa_dsl_pool->dp_meta_objset;
3630 
3631 	return (0);
3632 }
3633 
3634 static int
3635 spa_ld_trusted_config(spa_t *spa, spa_import_type_t type,
3636     boolean_t reloading)
3637 {
3638 	vdev_t *mrvd, *rvd = spa->spa_root_vdev;
3639 	nvlist_t *nv, *mos_config, *policy;
3640 	int error = 0, copy_error;
3641 	uint64_t healthy_tvds, healthy_tvds_mos;
3642 	uint64_t mos_config_txg;
3643 
3644 	if (spa_dir_prop(spa, DMU_POOL_CONFIG, &spa->spa_config_object, B_TRUE)
3645 	    != 0)
3646 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
3647 
3648 	/*
3649 	 * If we're assembling a pool from a split, the config provided is
3650 	 * already trusted so there is nothing to do.
3651 	 */
3652 	if (type == SPA_IMPORT_ASSEMBLE)
3653 		return (0);
3654 
3655 	healthy_tvds = spa_healthy_core_tvds(spa);
3656 
3657 	if (load_nvlist(spa, spa->spa_config_object, &mos_config)
3658 	    != 0) {
3659 		spa_load_failed(spa, "unable to retrieve MOS config");
3660 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
3661 	}
3662 
3663 	/*
3664 	 * If we are doing an open, pool owner wasn't verified yet, thus do
3665 	 * the verification here.
3666 	 */
3667 	if (spa->spa_load_state == SPA_LOAD_OPEN) {
3668 		error = spa_verify_host(spa, mos_config);
3669 		if (error != 0) {
3670 			nvlist_free(mos_config);
3671 			return (error);
3672 		}
3673 	}
3674 
3675 	nv = fnvlist_lookup_nvlist(mos_config, ZPOOL_CONFIG_VDEV_TREE);
3676 
3677 	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
3678 
3679 	/*
3680 	 * Build a new vdev tree from the trusted config
3681 	 */
3682 	error = spa_config_parse(spa, &mrvd, nv, NULL, 0, VDEV_ALLOC_LOAD);
3683 	if (error != 0) {
3684 		nvlist_free(mos_config);
3685 		spa_config_exit(spa, SCL_ALL, FTAG);
3686 		spa_load_failed(spa, "spa_config_parse failed [error=%d]",
3687 		    error);
3688 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, error));
3689 	}
3690 
3691 	/*
3692 	 * Vdev paths in the MOS may be obsolete. If the untrusted config was
3693 	 * obtained by scanning /dev/dsk, then it will have the right vdev
3694 	 * paths. We update the trusted MOS config with this information.
3695 	 * We first try to copy the paths with vdev_copy_path_strict, which
3696 	 * succeeds only when both configs have exactly the same vdev tree.
3697 	 * If that fails, we fall back to a more flexible method that has a
3698 	 * best effort policy.
3699 	 */
3700 	copy_error = vdev_copy_path_strict(rvd, mrvd);
3701 	if (copy_error != 0 || spa_load_print_vdev_tree) {
3702 		spa_load_note(spa, "provided vdev tree:");
3703 		vdev_dbgmsg_print_tree(rvd, 2);
3704 		spa_load_note(spa, "MOS vdev tree:");
3705 		vdev_dbgmsg_print_tree(mrvd, 2);
3706 	}
3707 	if (copy_error != 0) {
3708 		spa_load_note(spa, "vdev_copy_path_strict failed, falling "
3709 		    "back to vdev_copy_path_relaxed");
3710 		vdev_copy_path_relaxed(rvd, mrvd);
3711 	}
3712 
3713 	vdev_close(rvd);
3714 	vdev_free(rvd);
3715 	spa->spa_root_vdev = mrvd;
3716 	rvd = mrvd;
3717 	spa_config_exit(spa, SCL_ALL, FTAG);
3718 
3719 	/*
3720 	 * We will use spa_config if we decide to reload the spa or if spa_load
3721 	 * fails and we rewind. We must thus regenerate the config using the
3722 	 * MOS information with the updated paths. ZPOOL_LOAD_POLICY is used to
3723 	 * pass settings on how to load the pool and is not stored in the MOS.
3724 	 * We copy it over to our new, trusted config.
3725 	 */
3726 	mos_config_txg = fnvlist_lookup_uint64(mos_config,
3727 	    ZPOOL_CONFIG_POOL_TXG);
3728 	nvlist_free(mos_config);
3729 	mos_config = spa_config_generate(spa, NULL, mos_config_txg, B_FALSE);
3730 	if (nvlist_lookup_nvlist(spa->spa_config, ZPOOL_LOAD_POLICY,
3731 	    &policy) == 0)
3732 		fnvlist_add_nvlist(mos_config, ZPOOL_LOAD_POLICY, policy);
3733 	spa_config_set(spa, mos_config);
3734 	spa->spa_config_source = SPA_CONFIG_SRC_MOS;
3735 
3736 	/*
3737 	 * Now that we got the config from the MOS, we should be more strict
3738 	 * in checking blkptrs and can make assumptions about the consistency
3739 	 * of the vdev tree. spa_trust_config must be set to true before opening
3740 	 * vdevs in order for them to be writeable.
3741 	 */
3742 	spa->spa_trust_config = B_TRUE;
3743 
3744 	/*
3745 	 * Open and validate the new vdev tree
3746 	 */
3747 	error = spa_ld_open_vdevs(spa);
3748 	if (error != 0)
3749 		return (error);
3750 
3751 	error = spa_ld_validate_vdevs(spa);
3752 	if (error != 0)
3753 		return (error);
3754 
3755 	if (copy_error != 0 || spa_load_print_vdev_tree) {
3756 		spa_load_note(spa, "final vdev tree:");
3757 		vdev_dbgmsg_print_tree(rvd, 2);
3758 	}
3759 
3760 	if (spa->spa_load_state != SPA_LOAD_TRYIMPORT &&
3761 	    !spa->spa_extreme_rewind && zfs_max_missing_tvds == 0) {
3762 		/*
3763 		 * Sanity check to make sure that we are indeed loading the
3764 		 * latest uberblock. If we missed SPA_SYNC_MIN_VDEVS tvds
3765 		 * in the config provided and they happened to be the only ones
3766 		 * to have the latest uberblock, we could involuntarily perform
3767 		 * an extreme rewind.
3768 		 */
3769 		healthy_tvds_mos = spa_healthy_core_tvds(spa);
3770 		if (healthy_tvds_mos - healthy_tvds >=
3771 		    SPA_SYNC_MIN_VDEVS) {
3772 			spa_load_note(spa, "config provided misses too many "
3773 			    "top-level vdevs compared to MOS (%lld vs %lld). ",
3774 			    (u_longlong_t)healthy_tvds,
3775 			    (u_longlong_t)healthy_tvds_mos);
3776 			spa_load_note(spa, "vdev tree:");
3777 			vdev_dbgmsg_print_tree(rvd, 2);
3778 			if (reloading) {
3779 				spa_load_failed(spa, "config was already "
3780 				    "provided from MOS. Aborting.");
3781 				return (spa_vdev_err(rvd,
3782 				    VDEV_AUX_CORRUPT_DATA, EIO));
3783 			}
3784 			spa_load_note(spa, "spa must be reloaded using MOS "
3785 			    "config");
3786 			return (SET_ERROR(EAGAIN));
3787 		}
3788 	}
3789 
3790 	error = spa_check_for_missing_logs(spa);
3791 	if (error != 0)
3792 		return (spa_vdev_err(rvd, VDEV_AUX_BAD_GUID_SUM, ENXIO));
3793 
3794 	if (rvd->vdev_guid_sum != spa->spa_uberblock.ub_guid_sum) {
3795 		spa_load_failed(spa, "uberblock guid sum doesn't match MOS "
3796 		    "guid sum (%llu != %llu)",
3797 		    (u_longlong_t)spa->spa_uberblock.ub_guid_sum,
3798 		    (u_longlong_t)rvd->vdev_guid_sum);
3799 		return (spa_vdev_err(rvd, VDEV_AUX_BAD_GUID_SUM,
3800 		    ENXIO));
3801 	}
3802 
3803 	return (0);
3804 }
3805 
3806 static int
3807 spa_ld_open_indirect_vdev_metadata(spa_t *spa)
3808 {
3809 	int error = 0;
3810 	vdev_t *rvd = spa->spa_root_vdev;
3811 
3812 	/*
3813 	 * Everything that we read before spa_remove_init() must be stored
3814 	 * on concreted vdevs.  Therefore we do this as early as possible.
3815 	 */
3816 	error = spa_remove_init(spa);
3817 	if (error != 0) {
3818 		spa_load_failed(spa, "spa_remove_init failed [error=%d]",
3819 		    error);
3820 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
3821 	}
3822 
3823 	/*
3824 	 * Retrieve information needed to condense indirect vdev mappings.
3825 	 */
3826 	error = spa_condense_init(spa);
3827 	if (error != 0) {
3828 		spa_load_failed(spa, "spa_condense_init failed [error=%d]",
3829 		    error);
3830 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, error));
3831 	}
3832 
3833 	return (0);
3834 }
3835 
3836 static int
3837 spa_ld_check_features(spa_t *spa, boolean_t *missing_feat_writep)
3838 {
3839 	int error = 0;
3840 	vdev_t *rvd = spa->spa_root_vdev;
3841 
3842 	if (spa_version(spa) >= SPA_VERSION_FEATURES) {
3843 		boolean_t missing_feat_read = B_FALSE;
3844 		nvlist_t *unsup_feat, *enabled_feat;
3845 
3846 		if (spa_dir_prop(spa, DMU_POOL_FEATURES_FOR_READ,
3847 		    &spa->spa_feat_for_read_obj, B_TRUE) != 0) {
3848 			return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
3849 		}
3850 
3851 		if (spa_dir_prop(spa, DMU_POOL_FEATURES_FOR_WRITE,
3852 		    &spa->spa_feat_for_write_obj, B_TRUE) != 0) {
3853 			return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
3854 		}
3855 
3856 		if (spa_dir_prop(spa, DMU_POOL_FEATURE_DESCRIPTIONS,
3857 		    &spa->spa_feat_desc_obj, B_TRUE) != 0) {
3858 			return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
3859 		}
3860 
3861 		enabled_feat = fnvlist_alloc();
3862 		unsup_feat = fnvlist_alloc();
3863 
3864 		if (!spa_features_check(spa, B_FALSE,
3865 		    unsup_feat, enabled_feat))
3866 			missing_feat_read = B_TRUE;
3867 
3868 		if (spa_writeable(spa) ||
3869 		    spa->spa_load_state == SPA_LOAD_TRYIMPORT) {
3870 			if (!spa_features_check(spa, B_TRUE,
3871 			    unsup_feat, enabled_feat)) {
3872 				*missing_feat_writep = B_TRUE;
3873 			}
3874 		}
3875 
3876 		fnvlist_add_nvlist(spa->spa_load_info,
3877 		    ZPOOL_CONFIG_ENABLED_FEAT, enabled_feat);
3878 
3879 		if (!nvlist_empty(unsup_feat)) {
3880 			fnvlist_add_nvlist(spa->spa_load_info,
3881 			    ZPOOL_CONFIG_UNSUP_FEAT, unsup_feat);
3882 		}
3883 
3884 		fnvlist_free(enabled_feat);
3885 		fnvlist_free(unsup_feat);
3886 
3887 		if (!missing_feat_read) {
3888 			fnvlist_add_boolean(spa->spa_load_info,
3889 			    ZPOOL_CONFIG_CAN_RDONLY);
3890 		}
3891 
3892 		/*
3893 		 * If the state is SPA_LOAD_TRYIMPORT, our objective is
3894 		 * twofold: to determine whether the pool is available for
3895 		 * import in read-write mode and (if it is not) whether the
3896 		 * pool is available for import in read-only mode. If the pool
3897 		 * is available for import in read-write mode, it is displayed
3898 		 * as available in userland; if it is not available for import
3899 		 * in read-only mode, it is displayed as unavailable in
3900 		 * userland. If the pool is available for import in read-only
3901 		 * mode but not read-write mode, it is displayed as unavailable
3902 		 * in userland with a special note that the pool is actually
3903 		 * available for open in read-only mode.
3904 		 *
3905 		 * As a result, if the state is SPA_LOAD_TRYIMPORT and we are
3906 		 * missing a feature for write, we must first determine whether
3907 		 * the pool can be opened read-only before returning to
3908 		 * userland in order to know whether to display the
3909 		 * abovementioned note.
3910 		 */
3911 		if (missing_feat_read || (*missing_feat_writep &&
3912 		    spa_writeable(spa))) {
3913 			spa_load_failed(spa, "pool uses unsupported features");
3914 			return (spa_vdev_err(rvd, VDEV_AUX_UNSUP_FEAT,
3915 			    ENOTSUP));
3916 		}
3917 
3918 		/*
3919 		 * Load refcounts for ZFS features from disk into an in-memory
3920 		 * cache during SPA initialization.
3921 		 */
3922 		for (spa_feature_t i = 0; i < SPA_FEATURES; i++) {
3923 			uint64_t refcount;
3924 
3925 			error = feature_get_refcount_from_disk(spa,
3926 			    &spa_feature_table[i], &refcount);
3927 			if (error == 0) {
3928 				spa->spa_feat_refcount_cache[i] = refcount;
3929 			} else if (error == ENOTSUP) {
3930 				spa->spa_feat_refcount_cache[i] =
3931 				    SPA_FEATURE_DISABLED;
3932 			} else {
3933 				spa_load_failed(spa, "error getting refcount "
3934 				    "for feature %s [error=%d]",
3935 				    spa_feature_table[i].fi_guid, error);
3936 				return (spa_vdev_err(rvd,
3937 				    VDEV_AUX_CORRUPT_DATA, EIO));
3938 			}
3939 		}
3940 	}
3941 
3942 	if (spa_feature_is_active(spa, SPA_FEATURE_ENABLED_TXG)) {
3943 		if (spa_dir_prop(spa, DMU_POOL_FEATURE_ENABLED_TXG,
3944 		    &spa->spa_feat_enabled_txg_obj, B_TRUE) != 0)
3945 			return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
3946 	}
3947 
3948 	/*
3949 	 * Encryption was added before bookmark_v2, even though bookmark_v2
3950 	 * is now a dependency. If this pool has encryption enabled without
3951 	 * bookmark_v2, trigger an errata message.
3952 	 */
3953 	if (spa_feature_is_enabled(spa, SPA_FEATURE_ENCRYPTION) &&
3954 	    !spa_feature_is_enabled(spa, SPA_FEATURE_BOOKMARK_V2)) {
3955 		spa->spa_errata = ZPOOL_ERRATA_ZOL_8308_ENCRYPTION;
3956 	}
3957 
3958 	return (0);
3959 }
3960 
3961 static int
3962 spa_ld_load_special_directories(spa_t *spa)
3963 {
3964 	int error = 0;
3965 	vdev_t *rvd = spa->spa_root_vdev;
3966 
3967 	spa->spa_is_initializing = B_TRUE;
3968 	error = dsl_pool_open(spa->spa_dsl_pool);
3969 	spa->spa_is_initializing = B_FALSE;
3970 	if (error != 0) {
3971 		spa_load_failed(spa, "dsl_pool_open failed [error=%d]", error);
3972 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
3973 	}
3974 
3975 	return (0);
3976 }
3977 
3978 static int
3979 spa_ld_get_props(spa_t *spa)
3980 {
3981 	int error = 0;
3982 	uint64_t obj;
3983 	vdev_t *rvd = spa->spa_root_vdev;
3984 
3985 	/* Grab the checksum salt from the MOS. */
3986 	error = zap_lookup(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
3987 	    DMU_POOL_CHECKSUM_SALT, 1,
3988 	    sizeof (spa->spa_cksum_salt.zcs_bytes),
3989 	    spa->spa_cksum_salt.zcs_bytes);
3990 	if (error == ENOENT) {
3991 		/* Generate a new salt for subsequent use */
3992 		(void) random_get_pseudo_bytes(spa->spa_cksum_salt.zcs_bytes,
3993 		    sizeof (spa->spa_cksum_salt.zcs_bytes));
3994 	} else if (error != 0) {
3995 		spa_load_failed(spa, "unable to retrieve checksum salt from "
3996 		    "MOS [error=%d]", error);
3997 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
3998 	}
3999 
4000 	if (spa_dir_prop(spa, DMU_POOL_SYNC_BPOBJ, &obj, B_TRUE) != 0)
4001 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
4002 	error = bpobj_open(&spa->spa_deferred_bpobj, spa->spa_meta_objset, obj);
4003 	if (error != 0) {
4004 		spa_load_failed(spa, "error opening deferred-frees bpobj "
4005 		    "[error=%d]", error);
4006 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
4007 	}
4008 
4009 	/*
4010 	 * Load the bit that tells us to use the new accounting function
4011 	 * (raid-z deflation).  If we have an older pool, this will not
4012 	 * be present.
4013 	 */
4014 	error = spa_dir_prop(spa, DMU_POOL_DEFLATE, &spa->spa_deflate, B_FALSE);
4015 	if (error != 0 && error != ENOENT)
4016 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
4017 
4018 	error = spa_dir_prop(spa, DMU_POOL_CREATION_VERSION,
4019 	    &spa->spa_creation_version, B_FALSE);
4020 	if (error != 0 && error != ENOENT)
4021 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
4022 
4023 	/*
4024 	 * Load the persistent error log.  If we have an older pool, this will
4025 	 * not be present.
4026 	 */
4027 	error = spa_dir_prop(spa, DMU_POOL_ERRLOG_LAST, &spa->spa_errlog_last,
4028 	    B_FALSE);
4029 	if (error != 0 && error != ENOENT)
4030 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
4031 
4032 	error = spa_dir_prop(spa, DMU_POOL_ERRLOG_SCRUB,
4033 	    &spa->spa_errlog_scrub, B_FALSE);
4034 	if (error != 0 && error != ENOENT)
4035 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
4036 
4037 	/*
4038 	 * Load the livelist deletion field. If a livelist is queued for
4039 	 * deletion, indicate that in the spa
4040 	 */
4041 	error = spa_dir_prop(spa, DMU_POOL_DELETED_CLONES,
4042 	    &spa->spa_livelists_to_delete, B_FALSE);
4043 	if (error != 0 && error != ENOENT)
4044 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
4045 
4046 	/*
4047 	 * Load the history object.  If we have an older pool, this
4048 	 * will not be present.
4049 	 */
4050 	error = spa_dir_prop(spa, DMU_POOL_HISTORY, &spa->spa_history, B_FALSE);
4051 	if (error != 0 && error != ENOENT)
4052 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
4053 
4054 	/*
4055 	 * Load the per-vdev ZAP map. If we have an older pool, this will not
4056 	 * be present; in this case, defer its creation to a later time to
4057 	 * avoid dirtying the MOS this early / out of sync context. See
4058 	 * spa_sync_config_object.
4059 	 */
4060 
4061 	/* The sentinel is only available in the MOS config. */
4062 	nvlist_t *mos_config;
4063 	if (load_nvlist(spa, spa->spa_config_object, &mos_config) != 0) {
4064 		spa_load_failed(spa, "unable to retrieve MOS config");
4065 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
4066 	}
4067 
4068 	error = spa_dir_prop(spa, DMU_POOL_VDEV_ZAP_MAP,
4069 	    &spa->spa_all_vdev_zaps, B_FALSE);
4070 
4071 	if (error == ENOENT) {
4072 		VERIFY(!nvlist_exists(mos_config,
4073 		    ZPOOL_CONFIG_HAS_PER_VDEV_ZAPS));
4074 		spa->spa_avz_action = AVZ_ACTION_INITIALIZE;
4075 		ASSERT0(vdev_count_verify_zaps(spa->spa_root_vdev));
4076 	} else if (error != 0) {
4077 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
4078 	} else if (!nvlist_exists(mos_config, ZPOOL_CONFIG_HAS_PER_VDEV_ZAPS)) {
4079 		/*
4080 		 * An older version of ZFS overwrote the sentinel value, so
4081 		 * we have orphaned per-vdev ZAPs in the MOS. Defer their
4082 		 * destruction to later; see spa_sync_config_object.
4083 		 */
4084 		spa->spa_avz_action = AVZ_ACTION_DESTROY;
4085 		/*
4086 		 * We're assuming that no vdevs have had their ZAPs created
4087 		 * before this. Better be sure of it.
4088 		 */
4089 		ASSERT0(vdev_count_verify_zaps(spa->spa_root_vdev));
4090 	}
4091 	nvlist_free(mos_config);
4092 
4093 	spa->spa_delegation = zpool_prop_default_numeric(ZPOOL_PROP_DELEGATION);
4094 
4095 	error = spa_dir_prop(spa, DMU_POOL_PROPS, &spa->spa_pool_props_object,
4096 	    B_FALSE);
4097 	if (error && error != ENOENT)
4098 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
4099 
4100 	if (error == 0) {
4101 		uint64_t autoreplace;
4102 
4103 		spa_prop_find(spa, ZPOOL_PROP_BOOTFS, &spa->spa_bootfs);
4104 		spa_prop_find(spa, ZPOOL_PROP_AUTOREPLACE, &autoreplace);
4105 		spa_prop_find(spa, ZPOOL_PROP_DELEGATION, &spa->spa_delegation);
4106 		spa_prop_find(spa, ZPOOL_PROP_FAILUREMODE, &spa->spa_failmode);
4107 		spa_prop_find(spa, ZPOOL_PROP_AUTOEXPAND, &spa->spa_autoexpand);
4108 		spa_prop_find(spa, ZPOOL_PROP_MULTIHOST, &spa->spa_multihost);
4109 		spa_prop_find(spa, ZPOOL_PROP_AUTOTRIM, &spa->spa_autotrim);
4110 		spa->spa_autoreplace = (autoreplace != 0);
4111 	}
4112 
4113 	/*
4114 	 * If we are importing a pool with missing top-level vdevs,
4115 	 * we enforce that the pool doesn't panic or get suspended on
4116 	 * error since the likelihood of missing data is extremely high.
4117 	 */
4118 	if (spa->spa_missing_tvds > 0 &&
4119 	    spa->spa_failmode != ZIO_FAILURE_MODE_CONTINUE &&
4120 	    spa->spa_load_state != SPA_LOAD_TRYIMPORT) {
4121 		spa_load_note(spa, "forcing failmode to 'continue' "
4122 		    "as some top level vdevs are missing");
4123 		spa->spa_failmode = ZIO_FAILURE_MODE_CONTINUE;
4124 	}
4125 
4126 	return (0);
4127 }
4128 
4129 static int
4130 spa_ld_open_aux_vdevs(spa_t *spa, spa_import_type_t type)
4131 {
4132 	int error = 0;
4133 	vdev_t *rvd = spa->spa_root_vdev;
4134 
4135 	/*
4136 	 * If we're assembling the pool from the split-off vdevs of
4137 	 * an existing pool, we don't want to attach the spares & cache
4138 	 * devices.
4139 	 */
4140 
4141 	/*
4142 	 * Load any hot spares for this pool.
4143 	 */
4144 	error = spa_dir_prop(spa, DMU_POOL_SPARES, &spa->spa_spares.sav_object,
4145 	    B_FALSE);
4146 	if (error != 0 && error != ENOENT)
4147 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
4148 	if (error == 0 && type != SPA_IMPORT_ASSEMBLE) {
4149 		ASSERT(spa_version(spa) >= SPA_VERSION_SPARES);
4150 		if (load_nvlist(spa, spa->spa_spares.sav_object,
4151 		    &spa->spa_spares.sav_config) != 0) {
4152 			spa_load_failed(spa, "error loading spares nvlist");
4153 			return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
4154 		}
4155 
4156 		spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
4157 		spa_load_spares(spa);
4158 		spa_config_exit(spa, SCL_ALL, FTAG);
4159 	} else if (error == 0) {
4160 		spa->spa_spares.sav_sync = B_TRUE;
4161 	}
4162 
4163 	/*
4164 	 * Load any level 2 ARC devices for this pool.
4165 	 */
4166 	error = spa_dir_prop(spa, DMU_POOL_L2CACHE,
4167 	    &spa->spa_l2cache.sav_object, B_FALSE);
4168 	if (error != 0 && error != ENOENT)
4169 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
4170 	if (error == 0 && type != SPA_IMPORT_ASSEMBLE) {
4171 		ASSERT(spa_version(spa) >= SPA_VERSION_L2CACHE);
4172 		if (load_nvlist(spa, spa->spa_l2cache.sav_object,
4173 		    &spa->spa_l2cache.sav_config) != 0) {
4174 			spa_load_failed(spa, "error loading l2cache nvlist");
4175 			return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
4176 		}
4177 
4178 		spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
4179 		spa_load_l2cache(spa);
4180 		spa_config_exit(spa, SCL_ALL, FTAG);
4181 	} else if (error == 0) {
4182 		spa->spa_l2cache.sav_sync = B_TRUE;
4183 	}
4184 
4185 	return (0);
4186 }
4187 
4188 static int
4189 spa_ld_load_vdev_metadata(spa_t *spa)
4190 {
4191 	int error = 0;
4192 	vdev_t *rvd = spa->spa_root_vdev;
4193 
4194 	/*
4195 	 * If the 'multihost' property is set, then never allow a pool to
4196 	 * be imported when the system hostid is zero.  The exception to
4197 	 * this rule is zdb which is always allowed to access pools.
4198 	 */
4199 	if (spa_multihost(spa) && spa_get_hostid(spa) == 0 &&
4200 	    (spa->spa_import_flags & ZFS_IMPORT_SKIP_MMP) == 0) {
4201 		fnvlist_add_uint64(spa->spa_load_info,
4202 		    ZPOOL_CONFIG_MMP_STATE, MMP_STATE_NO_HOSTID);
4203 		return (spa_vdev_err(rvd, VDEV_AUX_ACTIVE, EREMOTEIO));
4204 	}
4205 
4206 	/*
4207 	 * If the 'autoreplace' property is set, then post a resource notifying
4208 	 * the ZFS DE that it should not issue any faults for unopenable
4209 	 * devices.  We also iterate over the vdevs, and post a sysevent for any
4210 	 * unopenable vdevs so that the normal autoreplace handler can take
4211 	 * over.
4212 	 */
4213 	if (spa->spa_autoreplace && spa->spa_load_state != SPA_LOAD_TRYIMPORT) {
4214 		spa_check_removed(spa->spa_root_vdev);
4215 		/*
4216 		 * For the import case, this is done in spa_import(), because
4217 		 * at this point we're using the spare definitions from
4218 		 * the MOS config, not necessarily from the userland config.
4219 		 */
4220 		if (spa->spa_load_state != SPA_LOAD_IMPORT) {
4221 			spa_aux_check_removed(&spa->spa_spares);
4222 			spa_aux_check_removed(&spa->spa_l2cache);
4223 		}
4224 	}
4225 
4226 	/*
4227 	 * Load the vdev metadata such as metaslabs, DTLs, spacemap object, etc.
4228 	 */
4229 	error = vdev_load(rvd);
4230 	if (error != 0) {
4231 		spa_load_failed(spa, "vdev_load failed [error=%d]", error);
4232 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, error));
4233 	}
4234 
4235 	error = spa_ld_log_spacemaps(spa);
4236 	if (error != 0) {
4237 		spa_load_failed(spa, "spa_ld_log_sm_data failed [error=%d]",
4238 		    error);
4239 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, error));
4240 	}
4241 
4242 	/*
4243 	 * Propagate the leaf DTLs we just loaded all the way up the vdev tree.
4244 	 */
4245 	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
4246 	vdev_dtl_reassess(rvd, 0, 0, B_FALSE, B_FALSE);
4247 	spa_config_exit(spa, SCL_ALL, FTAG);
4248 
4249 	return (0);
4250 }
4251 
4252 static int
4253 spa_ld_load_dedup_tables(spa_t *spa)
4254 {
4255 	int error = 0;
4256 	vdev_t *rvd = spa->spa_root_vdev;
4257 
4258 	error = ddt_load(spa);
4259 	if (error != 0) {
4260 		spa_load_failed(spa, "ddt_load failed [error=%d]", error);
4261 		return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
4262 	}
4263 
4264 	return (0);
4265 }
4266 
4267 static int
4268 spa_ld_verify_logs(spa_t *spa, spa_import_type_t type, char **ereport)
4269 {
4270 	vdev_t *rvd = spa->spa_root_vdev;
4271 
4272 	if (type != SPA_IMPORT_ASSEMBLE && spa_writeable(spa)) {
4273 		boolean_t missing = spa_check_logs(spa);
4274 		if (missing) {
4275 			if (spa->spa_missing_tvds != 0) {
4276 				spa_load_note(spa, "spa_check_logs failed "
4277 				    "so dropping the logs");
4278 			} else {
4279 				*ereport = FM_EREPORT_ZFS_LOG_REPLAY;
4280 				spa_load_failed(spa, "spa_check_logs failed");
4281 				return (spa_vdev_err(rvd, VDEV_AUX_BAD_LOG,
4282 				    ENXIO));
4283 			}
4284 		}
4285 	}
4286 
4287 	return (0);
4288 }
4289 
4290 static int
4291 spa_ld_verify_pool_data(spa_t *spa)
4292 {
4293 	int error = 0;
4294 	vdev_t *rvd = spa->spa_root_vdev;
4295 
4296 	/*
4297 	 * We've successfully opened the pool, verify that we're ready
4298 	 * to start pushing transactions.
4299 	 */
4300 	if (spa->spa_load_state != SPA_LOAD_TRYIMPORT) {
4301 		error = spa_load_verify(spa);
4302 		if (error != 0) {
4303 			spa_load_failed(spa, "spa_load_verify failed "
4304 			    "[error=%d]", error);
4305 			return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA,
4306 			    error));
4307 		}
4308 	}
4309 
4310 	return (0);
4311 }
4312 
4313 static void
4314 spa_ld_claim_log_blocks(spa_t *spa)
4315 {
4316 	dmu_tx_t *tx;
4317 	dsl_pool_t *dp = spa_get_dsl(spa);
4318 
4319 	/*
4320 	 * Claim log blocks that haven't been committed yet.
4321 	 * This must all happen in a single txg.
4322 	 * Note: spa_claim_max_txg is updated by spa_claim_notify(),
4323 	 * invoked from zil_claim_log_block()'s i/o done callback.
4324 	 * Price of rollback is that we abandon the log.
4325 	 */
4326 	spa->spa_claiming = B_TRUE;
4327 
4328 	tx = dmu_tx_create_assigned(dp, spa_first_txg(spa));
4329 	(void) dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
4330 	    zil_claim, tx, DS_FIND_CHILDREN);
4331 	dmu_tx_commit(tx);
4332 
4333 	spa->spa_claiming = B_FALSE;
4334 
4335 	spa_set_log_state(spa, SPA_LOG_GOOD);
4336 }
4337 
4338 static void
4339 spa_ld_check_for_config_update(spa_t *spa, uint64_t config_cache_txg,
4340     boolean_t update_config_cache)
4341 {
4342 	vdev_t *rvd = spa->spa_root_vdev;
4343 	int need_update = B_FALSE;
4344 
4345 	/*
4346 	 * If the config cache is stale, or we have uninitialized
4347 	 * metaslabs (see spa_vdev_add()), then update the config.
4348 	 *
4349 	 * If this is a verbatim import, trust the current
4350 	 * in-core spa_config and update the disk labels.
4351 	 */
4352 	if (update_config_cache || config_cache_txg != spa->spa_config_txg ||
4353 	    spa->spa_load_state == SPA_LOAD_IMPORT ||
4354 	    spa->spa_load_state == SPA_LOAD_RECOVER ||
4355 	    (spa->spa_import_flags & ZFS_IMPORT_VERBATIM))
4356 		need_update = B_TRUE;
4357 
4358 	for (int c = 0; c < rvd->vdev_children; c++)
4359 		if (rvd->vdev_child[c]->vdev_ms_array == 0)
4360 			need_update = B_TRUE;
4361 
4362 	/*
4363 	 * Update the config cache asynchronously in case we're the
4364 	 * root pool, in which case the config cache isn't writable yet.
4365 	 */
4366 	if (need_update)
4367 		spa_async_request(spa, SPA_ASYNC_CONFIG_UPDATE);
4368 }
4369 
4370 static void
4371 spa_ld_prepare_for_reload(spa_t *spa)
4372 {
4373 	spa_mode_t mode = spa->spa_mode;
4374 	int async_suspended = spa->spa_async_suspended;
4375 
4376 	spa_unload(spa);
4377 	spa_deactivate(spa);
4378 	spa_activate(spa, mode);
4379 
4380 	/*
4381 	 * We save the value of spa_async_suspended as it gets reset to 0 by
4382 	 * spa_unload(). We want to restore it back to the original value before
4383 	 * returning as we might be calling spa_async_resume() later.
4384 	 */
4385 	spa->spa_async_suspended = async_suspended;
4386 }
4387 
4388 static int
4389 spa_ld_read_checkpoint_txg(spa_t *spa)
4390 {
4391 	uberblock_t checkpoint;
4392 	int error = 0;
4393 
4394 	ASSERT0(spa->spa_checkpoint_txg);
4395 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
4396 
4397 	error = zap_lookup(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
4398 	    DMU_POOL_ZPOOL_CHECKPOINT, sizeof (uint64_t),
4399 	    sizeof (uberblock_t) / sizeof (uint64_t), &checkpoint);
4400 
4401 	if (error == ENOENT)
4402 		return (0);
4403 
4404 	if (error != 0)
4405 		return (error);
4406 
4407 	ASSERT3U(checkpoint.ub_txg, !=, 0);
4408 	ASSERT3U(checkpoint.ub_checkpoint_txg, !=, 0);
4409 	ASSERT3U(checkpoint.ub_timestamp, !=, 0);
4410 	spa->spa_checkpoint_txg = checkpoint.ub_txg;
4411 	spa->spa_checkpoint_info.sci_timestamp = checkpoint.ub_timestamp;
4412 
4413 	return (0);
4414 }
4415 
4416 static int
4417 spa_ld_mos_init(spa_t *spa, spa_import_type_t type)
4418 {
4419 	int error = 0;
4420 
4421 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
4422 	ASSERT(spa->spa_config_source != SPA_CONFIG_SRC_NONE);
4423 
4424 	/*
4425 	 * Never trust the config that is provided unless we are assembling
4426 	 * a pool following a split.
4427 	 * This means don't trust blkptrs and the vdev tree in general. This
4428 	 * also effectively puts the spa in read-only mode since
4429 	 * spa_writeable() checks for spa_trust_config to be true.
4430 	 * We will later load a trusted config from the MOS.
4431 	 */
4432 	if (type != SPA_IMPORT_ASSEMBLE)
4433 		spa->spa_trust_config = B_FALSE;
4434 
4435 	/*
4436 	 * Parse the config provided to create a vdev tree.
4437 	 */
4438 	error = spa_ld_parse_config(spa, type);
4439 	if (error != 0)
4440 		return (error);
4441 
4442 	spa_import_progress_add(spa);
4443 
4444 	/*
4445 	 * Now that we have the vdev tree, try to open each vdev. This involves
4446 	 * opening the underlying physical device, retrieving its geometry and
4447 	 * probing the vdev with a dummy I/O. The state of each vdev will be set
4448 	 * based on the success of those operations. After this we'll be ready
4449 	 * to read from the vdevs.
4450 	 */
4451 	error = spa_ld_open_vdevs(spa);
4452 	if (error != 0)
4453 		return (error);
4454 
4455 	/*
4456 	 * Read the label of each vdev and make sure that the GUIDs stored
4457 	 * there match the GUIDs in the config provided.
4458 	 * If we're assembling a new pool that's been split off from an
4459 	 * existing pool, the labels haven't yet been updated so we skip
4460 	 * validation for now.
4461 	 */
4462 	if (type != SPA_IMPORT_ASSEMBLE) {
4463 		error = spa_ld_validate_vdevs(spa);
4464 		if (error != 0)
4465 			return (error);
4466 	}
4467 
4468 	/*
4469 	 * Read all vdev labels to find the best uberblock (i.e. latest,
4470 	 * unless spa_load_max_txg is set) and store it in spa_uberblock. We
4471 	 * get the list of features required to read blkptrs in the MOS from
4472 	 * the vdev label with the best uberblock and verify that our version
4473 	 * of zfs supports them all.
4474 	 */
4475 	error = spa_ld_select_uberblock(spa, type);
4476 	if (error != 0)
4477 		return (error);
4478 
4479 	/*
4480 	 * Pass that uberblock to the dsl_pool layer which will open the root
4481 	 * blkptr. This blkptr points to the latest version of the MOS and will
4482 	 * allow us to read its contents.
4483 	 */
4484 	error = spa_ld_open_rootbp(spa);
4485 	if (error != 0)
4486 		return (error);
4487 
4488 	return (0);
4489 }
4490 
4491 static int
4492 spa_ld_checkpoint_rewind(spa_t *spa)
4493 {
4494 	uberblock_t checkpoint;
4495 	int error = 0;
4496 
4497 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
4498 	ASSERT(spa->spa_import_flags & ZFS_IMPORT_CHECKPOINT);
4499 
4500 	error = zap_lookup(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
4501 	    DMU_POOL_ZPOOL_CHECKPOINT, sizeof (uint64_t),
4502 	    sizeof (uberblock_t) / sizeof (uint64_t), &checkpoint);
4503 
4504 	if (error != 0) {
4505 		spa_load_failed(spa, "unable to retrieve checkpointed "
4506 		    "uberblock from the MOS config [error=%d]", error);
4507 
4508 		if (error == ENOENT)
4509 			error = ZFS_ERR_NO_CHECKPOINT;
4510 
4511 		return (error);
4512 	}
4513 
4514 	ASSERT3U(checkpoint.ub_txg, <, spa->spa_uberblock.ub_txg);
4515 	ASSERT3U(checkpoint.ub_txg, ==, checkpoint.ub_checkpoint_txg);
4516 
4517 	/*
4518 	 * We need to update the txg and timestamp of the checkpointed
4519 	 * uberblock to be higher than the latest one. This ensures that
4520 	 * the checkpointed uberblock is selected if we were to close and
4521 	 * reopen the pool right after we've written it in the vdev labels.
4522 	 * (also see block comment in vdev_uberblock_compare)
4523 	 */
4524 	checkpoint.ub_txg = spa->spa_uberblock.ub_txg + 1;
4525 	checkpoint.ub_timestamp = gethrestime_sec();
4526 
4527 	/*
4528 	 * Set current uberblock to be the checkpointed uberblock.
4529 	 */
4530 	spa->spa_uberblock = checkpoint;
4531 
4532 	/*
4533 	 * If we are doing a normal rewind, then the pool is open for
4534 	 * writing and we sync the "updated" checkpointed uberblock to
4535 	 * disk. Once this is done, we've basically rewound the whole
4536 	 * pool and there is no way back.
4537 	 *
4538 	 * There are cases when we don't want to attempt and sync the
4539 	 * checkpointed uberblock to disk because we are opening a
4540 	 * pool as read-only. Specifically, verifying the checkpointed
4541 	 * state with zdb, and importing the checkpointed state to get
4542 	 * a "preview" of its content.
4543 	 */
4544 	if (spa_writeable(spa)) {
4545 		vdev_t *rvd = spa->spa_root_vdev;
4546 
4547 		spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
4548 		vdev_t *svd[SPA_SYNC_MIN_VDEVS] = { NULL };
4549 		int svdcount = 0;
4550 		int children = rvd->vdev_children;
4551 		int c0 = spa_get_random(children);
4552 
4553 		for (int c = 0; c < children; c++) {
4554 			vdev_t *vd = rvd->vdev_child[(c0 + c) % children];
4555 
4556 			/* Stop when revisiting the first vdev */
4557 			if (c > 0 && svd[0] == vd)
4558 				break;
4559 
4560 			if (vd->vdev_ms_array == 0 || vd->vdev_islog ||
4561 			    !vdev_is_concrete(vd))
4562 				continue;
4563 
4564 			svd[svdcount++] = vd;
4565 			if (svdcount == SPA_SYNC_MIN_VDEVS)
4566 				break;
4567 		}
4568 		error = vdev_config_sync(svd, svdcount, spa->spa_first_txg);
4569 		if (error == 0)
4570 			spa->spa_last_synced_guid = rvd->vdev_guid;
4571 		spa_config_exit(spa, SCL_ALL, FTAG);
4572 
4573 		if (error != 0) {
4574 			spa_load_failed(spa, "failed to write checkpointed "
4575 			    "uberblock to the vdev labels [error=%d]", error);
4576 			return (error);
4577 		}
4578 	}
4579 
4580 	return (0);
4581 }
4582 
4583 static int
4584 spa_ld_mos_with_trusted_config(spa_t *spa, spa_import_type_t type,
4585     boolean_t *update_config_cache)
4586 {
4587 	int error;
4588 
4589 	/*
4590 	 * Parse the config for pool, open and validate vdevs,
4591 	 * select an uberblock, and use that uberblock to open
4592 	 * the MOS.
4593 	 */
4594 	error = spa_ld_mos_init(spa, type);
4595 	if (error != 0)
4596 		return (error);
4597 
4598 	/*
4599 	 * Retrieve the trusted config stored in the MOS and use it to create
4600 	 * a new, exact version of the vdev tree, then reopen all vdevs.
4601 	 */
4602 	error = spa_ld_trusted_config(spa, type, B_FALSE);
4603 	if (error == EAGAIN) {
4604 		if (update_config_cache != NULL)
4605 			*update_config_cache = B_TRUE;
4606 
4607 		/*
4608 		 * Redo the loading process with the trusted config if it is
4609 		 * too different from the untrusted config.
4610 		 */
4611 		spa_ld_prepare_for_reload(spa);
4612 		spa_load_note(spa, "RELOADING");
4613 		error = spa_ld_mos_init(spa, type);
4614 		if (error != 0)
4615 			return (error);
4616 
4617 		error = spa_ld_trusted_config(spa, type, B_TRUE);
4618 		if (error != 0)
4619 			return (error);
4620 
4621 	} else if (error != 0) {
4622 		return (error);
4623 	}
4624 
4625 	return (0);
4626 }
4627 
4628 /*
4629  * Load an existing storage pool, using the config provided. This config
4630  * describes which vdevs are part of the pool and is later validated against
4631  * partial configs present in each vdev's label and an entire copy of the
4632  * config stored in the MOS.
4633  */
4634 static int
4635 spa_load_impl(spa_t *spa, spa_import_type_t type, char **ereport)
4636 {
4637 	int error = 0;
4638 	boolean_t missing_feat_write = B_FALSE;
4639 	boolean_t checkpoint_rewind =
4640 	    (spa->spa_import_flags & ZFS_IMPORT_CHECKPOINT);
4641 	boolean_t update_config_cache = B_FALSE;
4642 
4643 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
4644 	ASSERT(spa->spa_config_source != SPA_CONFIG_SRC_NONE);
4645 
4646 	spa_load_note(spa, "LOADING");
4647 
4648 	error = spa_ld_mos_with_trusted_config(spa, type, &update_config_cache);
4649 	if (error != 0)
4650 		return (error);
4651 
4652 	/*
4653 	 * If we are rewinding to the checkpoint then we need to repeat
4654 	 * everything we've done so far in this function but this time
4655 	 * selecting the checkpointed uberblock and using that to open
4656 	 * the MOS.
4657 	 */
4658 	if (checkpoint_rewind) {
4659 		/*
4660 		 * If we are rewinding to the checkpoint update config cache
4661 		 * anyway.
4662 		 */
4663 		update_config_cache = B_TRUE;
4664 
4665 		/*
4666 		 * Extract the checkpointed uberblock from the current MOS
4667 		 * and use this as the pool's uberblock from now on. If the
4668 		 * pool is imported as writeable we also write the checkpoint
4669 		 * uberblock to the labels, making the rewind permanent.
4670 		 */
4671 		error = spa_ld_checkpoint_rewind(spa);
4672 		if (error != 0)
4673 			return (error);
4674 
4675 		/*
4676 		 * Redo the loading process again with the
4677 		 * checkpointed uberblock.
4678 		 */
4679 		spa_ld_prepare_for_reload(spa);
4680 		spa_load_note(spa, "LOADING checkpointed uberblock");
4681 		error = spa_ld_mos_with_trusted_config(spa, type, NULL);
4682 		if (error != 0)
4683 			return (error);
4684 	}
4685 
4686 	/*
4687 	 * Retrieve the checkpoint txg if the pool has a checkpoint.
4688 	 */
4689 	error = spa_ld_read_checkpoint_txg(spa);
4690 	if (error != 0)
4691 		return (error);
4692 
4693 	/*
4694 	 * Retrieve the mapping of indirect vdevs. Those vdevs were removed
4695 	 * from the pool and their contents were re-mapped to other vdevs. Note
4696 	 * that everything that we read before this step must have been
4697 	 * rewritten on concrete vdevs after the last device removal was
4698 	 * initiated. Otherwise we could be reading from indirect vdevs before
4699 	 * we have loaded their mappings.
4700 	 */
4701 	error = spa_ld_open_indirect_vdev_metadata(spa);
4702 	if (error != 0)
4703 		return (error);
4704 
4705 	/*
4706 	 * Retrieve the full list of active features from the MOS and check if
4707 	 * they are all supported.
4708 	 */
4709 	error = spa_ld_check_features(spa, &missing_feat_write);
4710 	if (error != 0)
4711 		return (error);
4712 
4713 	/*
4714 	 * Load several special directories from the MOS needed by the dsl_pool
4715 	 * layer.
4716 	 */
4717 	error = spa_ld_load_special_directories(spa);
4718 	if (error != 0)
4719 		return (error);
4720 
4721 	/*
4722 	 * Retrieve pool properties from the MOS.
4723 	 */
4724 	error = spa_ld_get_props(spa);
4725 	if (error != 0)
4726 		return (error);
4727 
4728 	/*
4729 	 * Retrieve the list of auxiliary devices - cache devices and spares -
4730 	 * and open them.
4731 	 */
4732 	error = spa_ld_open_aux_vdevs(spa, type);
4733 	if (error != 0)
4734 		return (error);
4735 
4736 	/*
4737 	 * Load the metadata for all vdevs. Also check if unopenable devices
4738 	 * should be autoreplaced.
4739 	 */
4740 	error = spa_ld_load_vdev_metadata(spa);
4741 	if (error != 0)
4742 		return (error);
4743 
4744 	error = spa_ld_load_dedup_tables(spa);
4745 	if (error != 0)
4746 		return (error);
4747 
4748 	/*
4749 	 * Verify the logs now to make sure we don't have any unexpected errors
4750 	 * when we claim log blocks later.
4751 	 */
4752 	error = spa_ld_verify_logs(spa, type, ereport);
4753 	if (error != 0)
4754 		return (error);
4755 
4756 	if (missing_feat_write) {
4757 		ASSERT(spa->spa_load_state == SPA_LOAD_TRYIMPORT);
4758 
4759 		/*
4760 		 * At this point, we know that we can open the pool in
4761 		 * read-only mode but not read-write mode. We now have enough
4762 		 * information and can return to userland.
4763 		 */
4764 		return (spa_vdev_err(spa->spa_root_vdev, VDEV_AUX_UNSUP_FEAT,
4765 		    ENOTSUP));
4766 	}
4767 
4768 	/*
4769 	 * Traverse the last txgs to make sure the pool was left off in a safe
4770 	 * state. When performing an extreme rewind, we verify the whole pool,
4771 	 * which can take a very long time.
4772 	 */
4773 	error = spa_ld_verify_pool_data(spa);
4774 	if (error != 0)
4775 		return (error);
4776 
4777 	/*
4778 	 * Calculate the deflated space for the pool. This must be done before
4779 	 * we write anything to the pool because we'd need to update the space
4780 	 * accounting using the deflated sizes.
4781 	 */
4782 	spa_update_dspace(spa);
4783 
4784 	/*
4785 	 * We have now retrieved all the information we needed to open the
4786 	 * pool. If we are importing the pool in read-write mode, a few
4787 	 * additional steps must be performed to finish the import.
4788 	 */
4789 	if (spa_writeable(spa) && (spa->spa_load_state == SPA_LOAD_RECOVER ||
4790 	    spa->spa_load_max_txg == UINT64_MAX)) {
4791 		uint64_t config_cache_txg = spa->spa_config_txg;
4792 
4793 		ASSERT(spa->spa_load_state != SPA_LOAD_TRYIMPORT);
4794 
4795 		/*
4796 		 * In case of a checkpoint rewind, log the original txg
4797 		 * of the checkpointed uberblock.
4798 		 */
4799 		if (checkpoint_rewind) {
4800 			spa_history_log_internal(spa, "checkpoint rewind",
4801 			    NULL, "rewound state to txg=%llu",
4802 			    (u_longlong_t)spa->spa_uberblock.ub_checkpoint_txg);
4803 		}
4804 
4805 		/*
4806 		 * Traverse the ZIL and claim all blocks.
4807 		 */
4808 		spa_ld_claim_log_blocks(spa);
4809 
4810 		/*
4811 		 * Kick-off the syncing thread.
4812 		 */
4813 		spa->spa_sync_on = B_TRUE;
4814 		txg_sync_start(spa->spa_dsl_pool);
4815 		mmp_thread_start(spa);
4816 
4817 		/*
4818 		 * Wait for all claims to sync.  We sync up to the highest
4819 		 * claimed log block birth time so that claimed log blocks
4820 		 * don't appear to be from the future.  spa_claim_max_txg
4821 		 * will have been set for us by ZIL traversal operations
4822 		 * performed above.
4823 		 */
4824 		txg_wait_synced(spa->spa_dsl_pool, spa->spa_claim_max_txg);
4825 
4826 		/*
4827 		 * Check if we need to request an update of the config. On the
4828 		 * next sync, we would update the config stored in vdev labels
4829 		 * and the cachefile (by default /etc/zfs/zpool.cache).
4830 		 */
4831 		spa_ld_check_for_config_update(spa, config_cache_txg,
4832 		    update_config_cache);
4833 
4834 		/*
4835 		 * Check if a rebuild was in progress and if so resume it.
4836 		 * Then check all DTLs to see if anything needs resilvering.
4837 		 * The resilver will be deferred if a rebuild was started.
4838 		 */
4839 		if (vdev_rebuild_active(spa->spa_root_vdev)) {
4840 			vdev_rebuild_restart(spa);
4841 		} else if (!dsl_scan_resilvering(spa->spa_dsl_pool) &&
4842 		    vdev_resilver_needed(spa->spa_root_vdev, NULL, NULL)) {
4843 			spa_async_request(spa, SPA_ASYNC_RESILVER);
4844 		}
4845 
4846 		/*
4847 		 * Log the fact that we booted up (so that we can detect if
4848 		 * we rebooted in the middle of an operation).
4849 		 */
4850 		spa_history_log_version(spa, "open", NULL);
4851 
4852 		spa_restart_removal(spa);
4853 		spa_spawn_aux_threads(spa);
4854 
4855 		/*
4856 		 * Delete any inconsistent datasets.
4857 		 *
4858 		 * Note:
4859 		 * Since we may be issuing deletes for clones here,
4860 		 * we make sure to do so after we've spawned all the
4861 		 * auxiliary threads above (from which the livelist
4862 		 * deletion zthr is part of).
4863 		 */
4864 		(void) dmu_objset_find(spa_name(spa),
4865 		    dsl_destroy_inconsistent, NULL, DS_FIND_CHILDREN);
4866 
4867 		/*
4868 		 * Clean up any stale temporary dataset userrefs.
4869 		 */
4870 		dsl_pool_clean_tmp_userrefs(spa->spa_dsl_pool);
4871 
4872 		spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER);
4873 		vdev_initialize_restart(spa->spa_root_vdev);
4874 		vdev_trim_restart(spa->spa_root_vdev);
4875 		vdev_autotrim_restart(spa);
4876 		spa_config_exit(spa, SCL_CONFIG, FTAG);
4877 	}
4878 
4879 	spa_import_progress_remove(spa_guid(spa));
4880 	spa_async_request(spa, SPA_ASYNC_L2CACHE_REBUILD);
4881 
4882 	spa_load_note(spa, "LOADED");
4883 
4884 	return (0);
4885 }
4886 
4887 static int
4888 spa_load_retry(spa_t *spa, spa_load_state_t state)
4889 {
4890 	spa_mode_t mode = spa->spa_mode;
4891 
4892 	spa_unload(spa);
4893 	spa_deactivate(spa);
4894 
4895 	spa->spa_load_max_txg = spa->spa_uberblock.ub_txg - 1;
4896 
4897 	spa_activate(spa, mode);
4898 	spa_async_suspend(spa);
4899 
4900 	spa_load_note(spa, "spa_load_retry: rewind, max txg: %llu",
4901 	    (u_longlong_t)spa->spa_load_max_txg);
4902 
4903 	return (spa_load(spa, state, SPA_IMPORT_EXISTING));
4904 }
4905 
4906 /*
4907  * If spa_load() fails this function will try loading prior txg's. If
4908  * 'state' is SPA_LOAD_RECOVER and one of these loads succeeds the pool
4909  * will be rewound to that txg. If 'state' is not SPA_LOAD_RECOVER this
4910  * function will not rewind the pool and will return the same error as
4911  * spa_load().
4912  */
4913 static int
4914 spa_load_best(spa_t *spa, spa_load_state_t state, uint64_t max_request,
4915     int rewind_flags)
4916 {
4917 	nvlist_t *loadinfo = NULL;
4918 	nvlist_t *config = NULL;
4919 	int load_error, rewind_error;
4920 	uint64_t safe_rewind_txg;
4921 	uint64_t min_txg;
4922 
4923 	if (spa->spa_load_txg && state == SPA_LOAD_RECOVER) {
4924 		spa->spa_load_max_txg = spa->spa_load_txg;
4925 		spa_set_log_state(spa, SPA_LOG_CLEAR);
4926 	} else {
4927 		spa->spa_load_max_txg = max_request;
4928 		if (max_request != UINT64_MAX)
4929 			spa->spa_extreme_rewind = B_TRUE;
4930 	}
4931 
4932 	load_error = rewind_error = spa_load(spa, state, SPA_IMPORT_EXISTING);
4933 	if (load_error == 0)
4934 		return (0);
4935 	if (load_error == ZFS_ERR_NO_CHECKPOINT) {
4936 		/*
4937 		 * When attempting checkpoint-rewind on a pool with no
4938 		 * checkpoint, we should not attempt to load uberblocks
4939 		 * from previous txgs when spa_load fails.
4940 		 */
4941 		ASSERT(spa->spa_import_flags & ZFS_IMPORT_CHECKPOINT);
4942 		spa_import_progress_remove(spa_guid(spa));
4943 		return (load_error);
4944 	}
4945 
4946 	if (spa->spa_root_vdev != NULL)
4947 		config = spa_config_generate(spa, NULL, -1ULL, B_TRUE);
4948 
4949 	spa->spa_last_ubsync_txg = spa->spa_uberblock.ub_txg;
4950 	spa->spa_last_ubsync_txg_ts = spa->spa_uberblock.ub_timestamp;
4951 
4952 	if (rewind_flags & ZPOOL_NEVER_REWIND) {
4953 		nvlist_free(config);
4954 		spa_import_progress_remove(spa_guid(spa));
4955 		return (load_error);
4956 	}
4957 
4958 	if (state == SPA_LOAD_RECOVER) {
4959 		/* Price of rolling back is discarding txgs, including log */
4960 		spa_set_log_state(spa, SPA_LOG_CLEAR);
4961 	} else {
4962 		/*
4963 		 * If we aren't rolling back save the load info from our first
4964 		 * import attempt so that we can restore it after attempting
4965 		 * to rewind.
4966 		 */
4967 		loadinfo = spa->spa_load_info;
4968 		spa->spa_load_info = fnvlist_alloc();
4969 	}
4970 
4971 	spa->spa_load_max_txg = spa->spa_last_ubsync_txg;
4972 	safe_rewind_txg = spa->spa_last_ubsync_txg - TXG_DEFER_SIZE;
4973 	min_txg = (rewind_flags & ZPOOL_EXTREME_REWIND) ?
4974 	    TXG_INITIAL : safe_rewind_txg;
4975 
4976 	/*
4977 	 * Continue as long as we're finding errors, we're still within
4978 	 * the acceptable rewind range, and we're still finding uberblocks
4979 	 */
4980 	while (rewind_error && spa->spa_uberblock.ub_txg >= min_txg &&
4981 	    spa->spa_uberblock.ub_txg <= spa->spa_load_max_txg) {
4982 		if (spa->spa_load_max_txg < safe_rewind_txg)
4983 			spa->spa_extreme_rewind = B_TRUE;
4984 		rewind_error = spa_load_retry(spa, state);
4985 	}
4986 
4987 	spa->spa_extreme_rewind = B_FALSE;
4988 	spa->spa_load_max_txg = UINT64_MAX;
4989 
4990 	if (config && (rewind_error || state != SPA_LOAD_RECOVER))
4991 		spa_config_set(spa, config);
4992 	else
4993 		nvlist_free(config);
4994 
4995 	if (state == SPA_LOAD_RECOVER) {
4996 		ASSERT3P(loadinfo, ==, NULL);
4997 		spa_import_progress_remove(spa_guid(spa));
4998 		return (rewind_error);
4999 	} else {
5000 		/* Store the rewind info as part of the initial load info */
5001 		fnvlist_add_nvlist(loadinfo, ZPOOL_CONFIG_REWIND_INFO,
5002 		    spa->spa_load_info);
5003 
5004 		/* Restore the initial load info */
5005 		fnvlist_free(spa->spa_load_info);
5006 		spa->spa_load_info = loadinfo;
5007 
5008 		spa_import_progress_remove(spa_guid(spa));
5009 		return (load_error);
5010 	}
5011 }
5012 
5013 /*
5014  * Pool Open/Import
5015  *
5016  * The import case is identical to an open except that the configuration is sent
5017  * down from userland, instead of grabbed from the configuration cache.  For the
5018  * case of an open, the pool configuration will exist in the
5019  * POOL_STATE_UNINITIALIZED state.
5020  *
5021  * The stats information (gen/count/ustats) is used to gather vdev statistics at
5022  * the same time open the pool, without having to keep around the spa_t in some
5023  * ambiguous state.
5024  */
5025 static int
5026 spa_open_common(const char *pool, spa_t **spapp, void *tag, nvlist_t *nvpolicy,
5027     nvlist_t **config)
5028 {
5029 	spa_t *spa;
5030 	spa_load_state_t state = SPA_LOAD_OPEN;
5031 	int error;
5032 	int locked = B_FALSE;
5033 	int firstopen = B_FALSE;
5034 
5035 	*spapp = NULL;
5036 
5037 	/*
5038 	 * As disgusting as this is, we need to support recursive calls to this
5039 	 * function because dsl_dir_open() is called during spa_load(), and ends
5040 	 * up calling spa_open() again.  The real fix is to figure out how to
5041 	 * avoid dsl_dir_open() calling this in the first place.
5042 	 */
5043 	if (MUTEX_NOT_HELD(&spa_namespace_lock)) {
5044 		mutex_enter(&spa_namespace_lock);
5045 		locked = B_TRUE;
5046 	}
5047 
5048 	if ((spa = spa_lookup(pool)) == NULL) {
5049 		if (locked)
5050 			mutex_exit(&spa_namespace_lock);
5051 		return (SET_ERROR(ENOENT));
5052 	}
5053 
5054 	if (spa->spa_state == POOL_STATE_UNINITIALIZED) {
5055 		zpool_load_policy_t policy;
5056 
5057 		firstopen = B_TRUE;
5058 
5059 		zpool_get_load_policy(nvpolicy ? nvpolicy : spa->spa_config,
5060 		    &policy);
5061 		if (policy.zlp_rewind & ZPOOL_DO_REWIND)
5062 			state = SPA_LOAD_RECOVER;
5063 
5064 		spa_activate(spa, spa_mode_global);
5065 
5066 		if (state != SPA_LOAD_RECOVER)
5067 			spa->spa_last_ubsync_txg = spa->spa_load_txg = 0;
5068 		spa->spa_config_source = SPA_CONFIG_SRC_CACHEFILE;
5069 
5070 		zfs_dbgmsg("spa_open_common: opening %s", pool);
5071 		error = spa_load_best(spa, state, policy.zlp_txg,
5072 		    policy.zlp_rewind);
5073 
5074 		if (error == EBADF) {
5075 			/*
5076 			 * If vdev_validate() returns failure (indicated by
5077 			 * EBADF), it indicates that one of the vdevs indicates
5078 			 * that the pool has been exported or destroyed.  If
5079 			 * this is the case, the config cache is out of sync and
5080 			 * we should remove the pool from the namespace.
5081 			 */
5082 			spa_unload(spa);
5083 			spa_deactivate(spa);
5084 			spa_write_cachefile(spa, B_TRUE, B_TRUE);
5085 			spa_remove(spa);
5086 			if (locked)
5087 				mutex_exit(&spa_namespace_lock);
5088 			return (SET_ERROR(ENOENT));
5089 		}
5090 
5091 		if (error) {
5092 			/*
5093 			 * We can't open the pool, but we still have useful
5094 			 * information: the state of each vdev after the
5095 			 * attempted vdev_open().  Return this to the user.
5096 			 */
5097 			if (config != NULL && spa->spa_config) {
5098 				VERIFY(nvlist_dup(spa->spa_config, config,
5099 				    KM_SLEEP) == 0);
5100 				VERIFY(nvlist_add_nvlist(*config,
5101 				    ZPOOL_CONFIG_LOAD_INFO,
5102 				    spa->spa_load_info) == 0);
5103 			}
5104 			spa_unload(spa);
5105 			spa_deactivate(spa);
5106 			spa->spa_last_open_failed = error;
5107 			if (locked)
5108 				mutex_exit(&spa_namespace_lock);
5109 			*spapp = NULL;
5110 			return (error);
5111 		}
5112 	}
5113 
5114 	spa_open_ref(spa, tag);
5115 
5116 	if (config != NULL)
5117 		*config = spa_config_generate(spa, NULL, -1ULL, B_TRUE);
5118 
5119 	/*
5120 	 * If we've recovered the pool, pass back any information we
5121 	 * gathered while doing the load.
5122 	 */
5123 	if (state == SPA_LOAD_RECOVER) {
5124 		VERIFY(nvlist_add_nvlist(*config, ZPOOL_CONFIG_LOAD_INFO,
5125 		    spa->spa_load_info) == 0);
5126 	}
5127 
5128 	if (locked) {
5129 		spa->spa_last_open_failed = 0;
5130 		spa->spa_last_ubsync_txg = 0;
5131 		spa->spa_load_txg = 0;
5132 		mutex_exit(&spa_namespace_lock);
5133 	}
5134 
5135 	if (firstopen)
5136 		zvol_create_minors_recursive(spa_name(spa));
5137 
5138 	*spapp = spa;
5139 
5140 	return (0);
5141 }
5142 
5143 int
5144 spa_open_rewind(const char *name, spa_t **spapp, void *tag, nvlist_t *policy,
5145     nvlist_t **config)
5146 {
5147 	return (spa_open_common(name, spapp, tag, policy, config));
5148 }
5149 
5150 int
5151 spa_open(const char *name, spa_t **spapp, void *tag)
5152 {
5153 	return (spa_open_common(name, spapp, tag, NULL, NULL));
5154 }
5155 
5156 /*
5157  * Lookup the given spa_t, incrementing the inject count in the process,
5158  * preventing it from being exported or destroyed.
5159  */
5160 spa_t *
5161 spa_inject_addref(char *name)
5162 {
5163 	spa_t *spa;
5164 
5165 	mutex_enter(&spa_namespace_lock);
5166 	if ((spa = spa_lookup(name)) == NULL) {
5167 		mutex_exit(&spa_namespace_lock);
5168 		return (NULL);
5169 	}
5170 	spa->spa_inject_ref++;
5171 	mutex_exit(&spa_namespace_lock);
5172 
5173 	return (spa);
5174 }
5175 
5176 void
5177 spa_inject_delref(spa_t *spa)
5178 {
5179 	mutex_enter(&spa_namespace_lock);
5180 	spa->spa_inject_ref--;
5181 	mutex_exit(&spa_namespace_lock);
5182 }
5183 
5184 /*
5185  * Add spares device information to the nvlist.
5186  */
5187 static void
5188 spa_add_spares(spa_t *spa, nvlist_t *config)
5189 {
5190 	nvlist_t **spares;
5191 	uint_t i, nspares;
5192 	nvlist_t *nvroot;
5193 	uint64_t guid;
5194 	vdev_stat_t *vs;
5195 	uint_t vsc;
5196 	uint64_t pool;
5197 
5198 	ASSERT(spa_config_held(spa, SCL_CONFIG, RW_READER));
5199 
5200 	if (spa->spa_spares.sav_count == 0)
5201 		return;
5202 
5203 	VERIFY(nvlist_lookup_nvlist(config,
5204 	    ZPOOL_CONFIG_VDEV_TREE, &nvroot) == 0);
5205 	VERIFY(nvlist_lookup_nvlist_array(spa->spa_spares.sav_config,
5206 	    ZPOOL_CONFIG_SPARES, &spares, &nspares) == 0);
5207 	if (nspares != 0) {
5208 		VERIFY(nvlist_add_nvlist_array(nvroot,
5209 		    ZPOOL_CONFIG_SPARES, spares, nspares) == 0);
5210 		VERIFY(nvlist_lookup_nvlist_array(nvroot,
5211 		    ZPOOL_CONFIG_SPARES, &spares, &nspares) == 0);
5212 
5213 		/*
5214 		 * Go through and find any spares which have since been
5215 		 * repurposed as an active spare.  If this is the case, update
5216 		 * their status appropriately.
5217 		 */
5218 		for (i = 0; i < nspares; i++) {
5219 			VERIFY(nvlist_lookup_uint64(spares[i],
5220 			    ZPOOL_CONFIG_GUID, &guid) == 0);
5221 			if (spa_spare_exists(guid, &pool, NULL) &&
5222 			    pool != 0ULL) {
5223 				VERIFY(nvlist_lookup_uint64_array(
5224 				    spares[i], ZPOOL_CONFIG_VDEV_STATS,
5225 				    (uint64_t **)&vs, &vsc) == 0);
5226 				vs->vs_state = VDEV_STATE_CANT_OPEN;
5227 				vs->vs_aux = VDEV_AUX_SPARED;
5228 			}
5229 		}
5230 	}
5231 }
5232 
5233 /*
5234  * Add l2cache device information to the nvlist, including vdev stats.
5235  */
5236 static void
5237 spa_add_l2cache(spa_t *spa, nvlist_t *config)
5238 {
5239 	nvlist_t **l2cache;
5240 	uint_t i, j, nl2cache;
5241 	nvlist_t *nvroot;
5242 	uint64_t guid;
5243 	vdev_t *vd;
5244 	vdev_stat_t *vs;
5245 	uint_t vsc;
5246 
5247 	ASSERT(spa_config_held(spa, SCL_CONFIG, RW_READER));
5248 
5249 	if (spa->spa_l2cache.sav_count == 0)
5250 		return;
5251 
5252 	VERIFY(nvlist_lookup_nvlist(config,
5253 	    ZPOOL_CONFIG_VDEV_TREE, &nvroot) == 0);
5254 	VERIFY(nvlist_lookup_nvlist_array(spa->spa_l2cache.sav_config,
5255 	    ZPOOL_CONFIG_L2CACHE, &l2cache, &nl2cache) == 0);
5256 	if (nl2cache != 0) {
5257 		VERIFY(nvlist_add_nvlist_array(nvroot,
5258 		    ZPOOL_CONFIG_L2CACHE, l2cache, nl2cache) == 0);
5259 		VERIFY(nvlist_lookup_nvlist_array(nvroot,
5260 		    ZPOOL_CONFIG_L2CACHE, &l2cache, &nl2cache) == 0);
5261 
5262 		/*
5263 		 * Update level 2 cache device stats.
5264 		 */
5265 
5266 		for (i = 0; i < nl2cache; i++) {
5267 			VERIFY(nvlist_lookup_uint64(l2cache[i],
5268 			    ZPOOL_CONFIG_GUID, &guid) == 0);
5269 
5270 			vd = NULL;
5271 			for (j = 0; j < spa->spa_l2cache.sav_count; j++) {
5272 				if (guid ==
5273 				    spa->spa_l2cache.sav_vdevs[j]->vdev_guid) {
5274 					vd = spa->spa_l2cache.sav_vdevs[j];
5275 					break;
5276 				}
5277 			}
5278 			ASSERT(vd != NULL);
5279 
5280 			VERIFY(nvlist_lookup_uint64_array(l2cache[i],
5281 			    ZPOOL_CONFIG_VDEV_STATS, (uint64_t **)&vs, &vsc)
5282 			    == 0);
5283 			vdev_get_stats(vd, vs);
5284 			vdev_config_generate_stats(vd, l2cache[i]);
5285 
5286 		}
5287 	}
5288 }
5289 
5290 static void
5291 spa_feature_stats_from_disk(spa_t *spa, nvlist_t *features)
5292 {
5293 	zap_cursor_t zc;
5294 	zap_attribute_t za;
5295 
5296 	if (spa->spa_feat_for_read_obj != 0) {
5297 		for (zap_cursor_init(&zc, spa->spa_meta_objset,
5298 		    spa->spa_feat_for_read_obj);
5299 		    zap_cursor_retrieve(&zc, &za) == 0;
5300 		    zap_cursor_advance(&zc)) {
5301 			ASSERT(za.za_integer_length == sizeof (uint64_t) &&
5302 			    za.za_num_integers == 1);
5303 			VERIFY0(nvlist_add_uint64(features, za.za_name,
5304 			    za.za_first_integer));
5305 		}
5306 		zap_cursor_fini(&zc);
5307 	}
5308 
5309 	if (spa->spa_feat_for_write_obj != 0) {
5310 		for (zap_cursor_init(&zc, spa->spa_meta_objset,
5311 		    spa->spa_feat_for_write_obj);
5312 		    zap_cursor_retrieve(&zc, &za) == 0;
5313 		    zap_cursor_advance(&zc)) {
5314 			ASSERT(za.za_integer_length == sizeof (uint64_t) &&
5315 			    za.za_num_integers == 1);
5316 			VERIFY0(nvlist_add_uint64(features, za.za_name,
5317 			    za.za_first_integer));
5318 		}
5319 		zap_cursor_fini(&zc);
5320 	}
5321 }
5322 
5323 static void
5324 spa_feature_stats_from_cache(spa_t *spa, nvlist_t *features)
5325 {
5326 	int i;
5327 
5328 	for (i = 0; i < SPA_FEATURES; i++) {
5329 		zfeature_info_t feature = spa_feature_table[i];
5330 		uint64_t refcount;
5331 
5332 		if (feature_get_refcount(spa, &feature, &refcount) != 0)
5333 			continue;
5334 
5335 		VERIFY0(nvlist_add_uint64(features, feature.fi_guid, refcount));
5336 	}
5337 }
5338 
5339 /*
5340  * Store a list of pool features and their reference counts in the
5341  * config.
5342  *
5343  * The first time this is called on a spa, allocate a new nvlist, fetch
5344  * the pool features and reference counts from disk, then save the list
5345  * in the spa. In subsequent calls on the same spa use the saved nvlist
5346  * and refresh its values from the cached reference counts.  This
5347  * ensures we don't block here on I/O on a suspended pool so 'zpool
5348  * clear' can resume the pool.
5349  */
5350 static void
5351 spa_add_feature_stats(spa_t *spa, nvlist_t *config)
5352 {
5353 	nvlist_t *features;
5354 
5355 	ASSERT(spa_config_held(spa, SCL_CONFIG, RW_READER));
5356 
5357 	mutex_enter(&spa->spa_feat_stats_lock);
5358 	features = spa->spa_feat_stats;
5359 
5360 	if (features != NULL) {
5361 		spa_feature_stats_from_cache(spa, features);
5362 	} else {
5363 		VERIFY0(nvlist_alloc(&features, NV_UNIQUE_NAME, KM_SLEEP));
5364 		spa->spa_feat_stats = features;
5365 		spa_feature_stats_from_disk(spa, features);
5366 	}
5367 
5368 	VERIFY0(nvlist_add_nvlist(config, ZPOOL_CONFIG_FEATURE_STATS,
5369 	    features));
5370 
5371 	mutex_exit(&spa->spa_feat_stats_lock);
5372 }
5373 
5374 int
5375 spa_get_stats(const char *name, nvlist_t **config,
5376     char *altroot, size_t buflen)
5377 {
5378 	int error;
5379 	spa_t *spa;
5380 
5381 	*config = NULL;
5382 	error = spa_open_common(name, &spa, FTAG, NULL, config);
5383 
5384 	if (spa != NULL) {
5385 		/*
5386 		 * This still leaves a window of inconsistency where the spares
5387 		 * or l2cache devices could change and the config would be
5388 		 * self-inconsistent.
5389 		 */
5390 		spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER);
5391 
5392 		if (*config != NULL) {
5393 			uint64_t loadtimes[2];
5394 
5395 			loadtimes[0] = spa->spa_loaded_ts.tv_sec;
5396 			loadtimes[1] = spa->spa_loaded_ts.tv_nsec;
5397 			VERIFY(nvlist_add_uint64_array(*config,
5398 			    ZPOOL_CONFIG_LOADED_TIME, loadtimes, 2) == 0);
5399 
5400 			VERIFY(nvlist_add_uint64(*config,
5401 			    ZPOOL_CONFIG_ERRCOUNT,
5402 			    spa_get_errlog_size(spa)) == 0);
5403 
5404 			if (spa_suspended(spa)) {
5405 				VERIFY(nvlist_add_uint64(*config,
5406 				    ZPOOL_CONFIG_SUSPENDED,
5407 				    spa->spa_failmode) == 0);
5408 				VERIFY(nvlist_add_uint64(*config,
5409 				    ZPOOL_CONFIG_SUSPENDED_REASON,
5410 				    spa->spa_suspended) == 0);
5411 			}
5412 
5413 			spa_add_spares(spa, *config);
5414 			spa_add_l2cache(spa, *config);
5415 			spa_add_feature_stats(spa, *config);
5416 		}
5417 	}
5418 
5419 	/*
5420 	 * We want to get the alternate root even for faulted pools, so we cheat
5421 	 * and call spa_lookup() directly.
5422 	 */
5423 	if (altroot) {
5424 		if (spa == NULL) {
5425 			mutex_enter(&spa_namespace_lock);
5426 			spa = spa_lookup(name);
5427 			if (spa)
5428 				spa_altroot(spa, altroot, buflen);
5429 			else
5430 				altroot[0] = '\0';
5431 			spa = NULL;
5432 			mutex_exit(&spa_namespace_lock);
5433 		} else {
5434 			spa_altroot(spa, altroot, buflen);
5435 		}
5436 	}
5437 
5438 	if (spa != NULL) {
5439 		spa_config_exit(spa, SCL_CONFIG, FTAG);
5440 		spa_close(spa, FTAG);
5441 	}
5442 
5443 	return (error);
5444 }
5445 
5446 /*
5447  * Validate that the auxiliary device array is well formed.  We must have an
5448  * array of nvlists, each which describes a valid leaf vdev.  If this is an
5449  * import (mode is VDEV_ALLOC_SPARE), then we allow corrupted spares to be
5450  * specified, as long as they are well-formed.
5451  */
5452 static int
5453 spa_validate_aux_devs(spa_t *spa, nvlist_t *nvroot, uint64_t crtxg, int mode,
5454     spa_aux_vdev_t *sav, const char *config, uint64_t version,
5455     vdev_labeltype_t label)
5456 {
5457 	nvlist_t **dev;
5458 	uint_t i, ndev;
5459 	vdev_t *vd;
5460 	int error;
5461 
5462 	ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL);
5463 
5464 	/*
5465 	 * It's acceptable to have no devs specified.
5466 	 */
5467 	if (nvlist_lookup_nvlist_array(nvroot, config, &dev, &ndev) != 0)
5468 		return (0);
5469 
5470 	if (ndev == 0)
5471 		return (SET_ERROR(EINVAL));
5472 
5473 	/*
5474 	 * Make sure the pool is formatted with a version that supports this
5475 	 * device type.
5476 	 */
5477 	if (spa_version(spa) < version)
5478 		return (SET_ERROR(ENOTSUP));
5479 
5480 	/*
5481 	 * Set the pending device list so we correctly handle device in-use
5482 	 * checking.
5483 	 */
5484 	sav->sav_pending = dev;
5485 	sav->sav_npending = ndev;
5486 
5487 	for (i = 0; i < ndev; i++) {
5488 		if ((error = spa_config_parse(spa, &vd, dev[i], NULL, 0,
5489 		    mode)) != 0)
5490 			goto out;
5491 
5492 		if (!vd->vdev_ops->vdev_op_leaf) {
5493 			vdev_free(vd);
5494 			error = SET_ERROR(EINVAL);
5495 			goto out;
5496 		}
5497 
5498 		vd->vdev_top = vd;
5499 
5500 		if ((error = vdev_open(vd)) == 0 &&
5501 		    (error = vdev_label_init(vd, crtxg, label)) == 0) {
5502 			VERIFY(nvlist_add_uint64(dev[i], ZPOOL_CONFIG_GUID,
5503 			    vd->vdev_guid) == 0);
5504 		}
5505 
5506 		vdev_free(vd);
5507 
5508 		if (error &&
5509 		    (mode != VDEV_ALLOC_SPARE && mode != VDEV_ALLOC_L2CACHE))
5510 			goto out;
5511 		else
5512 			error = 0;
5513 	}
5514 
5515 out:
5516 	sav->sav_pending = NULL;
5517 	sav->sav_npending = 0;
5518 	return (error);
5519 }
5520 
5521 static int
5522 spa_validate_aux(spa_t *spa, nvlist_t *nvroot, uint64_t crtxg, int mode)
5523 {
5524 	int error;
5525 
5526 	ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL);
5527 
5528 	if ((error = spa_validate_aux_devs(spa, nvroot, crtxg, mode,
5529 	    &spa->spa_spares, ZPOOL_CONFIG_SPARES, SPA_VERSION_SPARES,
5530 	    VDEV_LABEL_SPARE)) != 0) {
5531 		return (error);
5532 	}
5533 
5534 	return (spa_validate_aux_devs(spa, nvroot, crtxg, mode,
5535 	    &spa->spa_l2cache, ZPOOL_CONFIG_L2CACHE, SPA_VERSION_L2CACHE,
5536 	    VDEV_LABEL_L2CACHE));
5537 }
5538 
5539 static void
5540 spa_set_aux_vdevs(spa_aux_vdev_t *sav, nvlist_t **devs, int ndevs,
5541     const char *config)
5542 {
5543 	int i;
5544 
5545 	if (sav->sav_config != NULL) {
5546 		nvlist_t **olddevs;
5547 		uint_t oldndevs;
5548 		nvlist_t **newdevs;
5549 
5550 		/*
5551 		 * Generate new dev list by concatenating with the
5552 		 * current dev list.
5553 		 */
5554 		VERIFY(nvlist_lookup_nvlist_array(sav->sav_config, config,
5555 		    &olddevs, &oldndevs) == 0);
5556 
5557 		newdevs = kmem_alloc(sizeof (void *) *
5558 		    (ndevs + oldndevs), KM_SLEEP);
5559 		for (i = 0; i < oldndevs; i++)
5560 			VERIFY(nvlist_dup(olddevs[i], &newdevs[i],
5561 			    KM_SLEEP) == 0);
5562 		for (i = 0; i < ndevs; i++)
5563 			VERIFY(nvlist_dup(devs[i], &newdevs[i + oldndevs],
5564 			    KM_SLEEP) == 0);
5565 
5566 		VERIFY(nvlist_remove(sav->sav_config, config,
5567 		    DATA_TYPE_NVLIST_ARRAY) == 0);
5568 
5569 		VERIFY(nvlist_add_nvlist_array(sav->sav_config,
5570 		    config, newdevs, ndevs + oldndevs) == 0);
5571 		for (i = 0; i < oldndevs + ndevs; i++)
5572 			nvlist_free(newdevs[i]);
5573 		kmem_free(newdevs, (oldndevs + ndevs) * sizeof (void *));
5574 	} else {
5575 		/*
5576 		 * Generate a new dev list.
5577 		 */
5578 		VERIFY(nvlist_alloc(&sav->sav_config, NV_UNIQUE_NAME,
5579 		    KM_SLEEP) == 0);
5580 		VERIFY(nvlist_add_nvlist_array(sav->sav_config, config,
5581 		    devs, ndevs) == 0);
5582 	}
5583 }
5584 
5585 /*
5586  * Stop and drop level 2 ARC devices
5587  */
5588 void
5589 spa_l2cache_drop(spa_t *spa)
5590 {
5591 	vdev_t *vd;
5592 	int i;
5593 	spa_aux_vdev_t *sav = &spa->spa_l2cache;
5594 
5595 	for (i = 0; i < sav->sav_count; i++) {
5596 		uint64_t pool;
5597 
5598 		vd = sav->sav_vdevs[i];
5599 		ASSERT(vd != NULL);
5600 
5601 		if (spa_l2cache_exists(vd->vdev_guid, &pool) &&
5602 		    pool != 0ULL && l2arc_vdev_present(vd))
5603 			l2arc_remove_vdev(vd);
5604 	}
5605 }
5606 
5607 /*
5608  * Verify encryption parameters for spa creation. If we are encrypting, we must
5609  * have the encryption feature flag enabled.
5610  */
5611 static int
5612 spa_create_check_encryption_params(dsl_crypto_params_t *dcp,
5613     boolean_t has_encryption)
5614 {
5615 	if (dcp->cp_crypt != ZIO_CRYPT_OFF &&
5616 	    dcp->cp_crypt != ZIO_CRYPT_INHERIT &&
5617 	    !has_encryption)
5618 		return (SET_ERROR(ENOTSUP));
5619 
5620 	return (dmu_objset_create_crypt_check(NULL, dcp, NULL));
5621 }
5622 
5623 /*
5624  * Pool Creation
5625  */
5626 int
5627 spa_create(const char *pool, nvlist_t *nvroot, nvlist_t *props,
5628     nvlist_t *zplprops, dsl_crypto_params_t *dcp)
5629 {
5630 	spa_t *spa;
5631 	char *altroot = NULL;
5632 	vdev_t *rvd;
5633 	dsl_pool_t *dp;
5634 	dmu_tx_t *tx;
5635 	int error = 0;
5636 	uint64_t txg = TXG_INITIAL;
5637 	nvlist_t **spares, **l2cache;
5638 	uint_t nspares, nl2cache;
5639 	uint64_t version, obj, ndraid = 0;
5640 	boolean_t has_features;
5641 	boolean_t has_encryption;
5642 	boolean_t has_allocclass;
5643 	spa_feature_t feat;
5644 	char *feat_name;
5645 	char *poolname;
5646 	nvlist_t *nvl;
5647 
5648 	if (props == NULL ||
5649 	    nvlist_lookup_string(props, "tname", &poolname) != 0)
5650 		poolname = (char *)pool;
5651 
5652 	/*
5653 	 * If this pool already exists, return failure.
5654 	 */
5655 	mutex_enter(&spa_namespace_lock);
5656 	if (spa_lookup(poolname) != NULL) {
5657 		mutex_exit(&spa_namespace_lock);
5658 		return (SET_ERROR(EEXIST));
5659 	}
5660 
5661 	/*
5662 	 * Allocate a new spa_t structure.
5663 	 */
5664 	nvl = fnvlist_alloc();
5665 	fnvlist_add_string(nvl, ZPOOL_CONFIG_POOL_NAME, pool);
5666 	(void) nvlist_lookup_string(props,
5667 	    zpool_prop_to_name(ZPOOL_PROP_ALTROOT), &altroot);
5668 	spa = spa_add(poolname, nvl, altroot);
5669 	fnvlist_free(nvl);
5670 	spa_activate(spa, spa_mode_global);
5671 
5672 	if (props && (error = spa_prop_validate(spa, props))) {
5673 		spa_deactivate(spa);
5674 		spa_remove(spa);
5675 		mutex_exit(&spa_namespace_lock);
5676 		return (error);
5677 	}
5678 
5679 	/*
5680 	 * Temporary pool names should never be written to disk.
5681 	 */
5682 	if (poolname != pool)
5683 		spa->spa_import_flags |= ZFS_IMPORT_TEMP_NAME;
5684 
5685 	has_features = B_FALSE;
5686 	has_encryption = B_FALSE;
5687 	has_allocclass = B_FALSE;
5688 	for (nvpair_t *elem = nvlist_next_nvpair(props, NULL);
5689 	    elem != NULL; elem = nvlist_next_nvpair(props, elem)) {
5690 		if (zpool_prop_feature(nvpair_name(elem))) {
5691 			has_features = B_TRUE;
5692 
5693 			feat_name = strchr(nvpair_name(elem), '@') + 1;
5694 			VERIFY0(zfeature_lookup_name(feat_name, &feat));
5695 			if (feat == SPA_FEATURE_ENCRYPTION)
5696 				has_encryption = B_TRUE;
5697 			if (feat == SPA_FEATURE_ALLOCATION_CLASSES)
5698 				has_allocclass = B_TRUE;
5699 		}
5700 	}
5701 
5702 	/* verify encryption params, if they were provided */
5703 	if (dcp != NULL) {
5704 		error = spa_create_check_encryption_params(dcp, has_encryption);
5705 		if (error != 0) {
5706 			spa_deactivate(spa);
5707 			spa_remove(spa);
5708 			mutex_exit(&spa_namespace_lock);
5709 			return (error);
5710 		}
5711 	}
5712 	if (!has_allocclass && zfs_special_devs(nvroot, NULL)) {
5713 		spa_deactivate(spa);
5714 		spa_remove(spa);
5715 		mutex_exit(&spa_namespace_lock);
5716 		return (ENOTSUP);
5717 	}
5718 
5719 	if (has_features || nvlist_lookup_uint64(props,
5720 	    zpool_prop_to_name(ZPOOL_PROP_VERSION), &version) != 0) {
5721 		version = SPA_VERSION;
5722 	}
5723 	ASSERT(SPA_VERSION_IS_SUPPORTED(version));
5724 
5725 	spa->spa_first_txg = txg;
5726 	spa->spa_uberblock.ub_txg = txg - 1;
5727 	spa->spa_uberblock.ub_version = version;
5728 	spa->spa_ubsync = spa->spa_uberblock;
5729 	spa->spa_load_state = SPA_LOAD_CREATE;
5730 	spa->spa_removing_phys.sr_state = DSS_NONE;
5731 	spa->spa_removing_phys.sr_removing_vdev = -1;
5732 	spa->spa_removing_phys.sr_prev_indirect_vdev = -1;
5733 	spa->spa_indirect_vdevs_loaded = B_TRUE;
5734 
5735 	/*
5736 	 * Create "The Godfather" zio to hold all async IOs
5737 	 */
5738 	spa->spa_async_zio_root = kmem_alloc(max_ncpus * sizeof (void *),
5739 	    KM_SLEEP);
5740 	for (int i = 0; i < max_ncpus; i++) {
5741 		spa->spa_async_zio_root[i] = zio_root(spa, NULL, NULL,
5742 		    ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE |
5743 		    ZIO_FLAG_GODFATHER);
5744 	}
5745 
5746 	/*
5747 	 * Create the root vdev.
5748 	 */
5749 	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
5750 
5751 	error = spa_config_parse(spa, &rvd, nvroot, NULL, 0, VDEV_ALLOC_ADD);
5752 
5753 	ASSERT(error != 0 || rvd != NULL);
5754 	ASSERT(error != 0 || spa->spa_root_vdev == rvd);
5755 
5756 	if (error == 0 && !zfs_allocatable_devs(nvroot))
5757 		error = SET_ERROR(EINVAL);
5758 
5759 	if (error == 0 &&
5760 	    (error = vdev_create(rvd, txg, B_FALSE)) == 0 &&
5761 	    (error = vdev_draid_spare_create(nvroot, rvd, &ndraid, 0)) == 0 &&
5762 	    (error = spa_validate_aux(spa, nvroot, txg, VDEV_ALLOC_ADD)) == 0) {
5763 		/*
5764 		 * instantiate the metaslab groups (this will dirty the vdevs)
5765 		 * we can no longer error exit past this point
5766 		 */
5767 		for (int c = 0; error == 0 && c < rvd->vdev_children; c++) {
5768 			vdev_t *vd = rvd->vdev_child[c];
5769 
5770 			vdev_metaslab_set_size(vd);
5771 			vdev_expand(vd, txg);
5772 		}
5773 	}
5774 
5775 	spa_config_exit(spa, SCL_ALL, FTAG);
5776 
5777 	if (error != 0) {
5778 		spa_unload(spa);
5779 		spa_deactivate(spa);
5780 		spa_remove(spa);
5781 		mutex_exit(&spa_namespace_lock);
5782 		return (error);
5783 	}
5784 
5785 	/*
5786 	 * Get the list of spares, if specified.
5787 	 */
5788 	if (nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_SPARES,
5789 	    &spares, &nspares) == 0) {
5790 		VERIFY(nvlist_alloc(&spa->spa_spares.sav_config, NV_UNIQUE_NAME,
5791 		    KM_SLEEP) == 0);
5792 		VERIFY(nvlist_add_nvlist_array(spa->spa_spares.sav_config,
5793 		    ZPOOL_CONFIG_SPARES, spares, nspares) == 0);
5794 		spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
5795 		spa_load_spares(spa);
5796 		spa_config_exit(spa, SCL_ALL, FTAG);
5797 		spa->spa_spares.sav_sync = B_TRUE;
5798 	}
5799 
5800 	/*
5801 	 * Get the list of level 2 cache devices, if specified.
5802 	 */
5803 	if (nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_L2CACHE,
5804 	    &l2cache, &nl2cache) == 0) {
5805 		VERIFY(nvlist_alloc(&spa->spa_l2cache.sav_config,
5806 		    NV_UNIQUE_NAME, KM_SLEEP) == 0);
5807 		VERIFY(nvlist_add_nvlist_array(spa->spa_l2cache.sav_config,
5808 		    ZPOOL_CONFIG_L2CACHE, l2cache, nl2cache) == 0);
5809 		spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
5810 		spa_load_l2cache(spa);
5811 		spa_config_exit(spa, SCL_ALL, FTAG);
5812 		spa->spa_l2cache.sav_sync = B_TRUE;
5813 	}
5814 
5815 	spa->spa_is_initializing = B_TRUE;
5816 	spa->spa_dsl_pool = dp = dsl_pool_create(spa, zplprops, dcp, txg);
5817 	spa->spa_is_initializing = B_FALSE;
5818 
5819 	/*
5820 	 * Create DDTs (dedup tables).
5821 	 */
5822 	ddt_create(spa);
5823 
5824 	spa_update_dspace(spa);
5825 
5826 	tx = dmu_tx_create_assigned(dp, txg);
5827 
5828 	/*
5829 	 * Create the pool's history object.
5830 	 */
5831 	if (version >= SPA_VERSION_ZPOOL_HISTORY && !spa->spa_history)
5832 		spa_history_create_obj(spa, tx);
5833 
5834 	spa_event_notify(spa, NULL, NULL, ESC_ZFS_POOL_CREATE);
5835 	spa_history_log_version(spa, "create", tx);
5836 
5837 	/*
5838 	 * Create the pool config object.
5839 	 */
5840 	spa->spa_config_object = dmu_object_alloc(spa->spa_meta_objset,
5841 	    DMU_OT_PACKED_NVLIST, SPA_CONFIG_BLOCKSIZE,
5842 	    DMU_OT_PACKED_NVLIST_SIZE, sizeof (uint64_t), tx);
5843 
5844 	if (zap_add(spa->spa_meta_objset,
5845 	    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_CONFIG,
5846 	    sizeof (uint64_t), 1, &spa->spa_config_object, tx) != 0) {
5847 		cmn_err(CE_PANIC, "failed to add pool config");
5848 	}
5849 
5850 	if (zap_add(spa->spa_meta_objset,
5851 	    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_CREATION_VERSION,
5852 	    sizeof (uint64_t), 1, &version, tx) != 0) {
5853 		cmn_err(CE_PANIC, "failed to add pool version");
5854 	}
5855 
5856 	/* Newly created pools with the right version are always deflated. */
5857 	if (version >= SPA_VERSION_RAIDZ_DEFLATE) {
5858 		spa->spa_deflate = TRUE;
5859 		if (zap_add(spa->spa_meta_objset,
5860 		    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_DEFLATE,
5861 		    sizeof (uint64_t), 1, &spa->spa_deflate, tx) != 0) {
5862 			cmn_err(CE_PANIC, "failed to add deflate");
5863 		}
5864 	}
5865 
5866 	/*
5867 	 * Create the deferred-free bpobj.  Turn off compression
5868 	 * because sync-to-convergence takes longer if the blocksize
5869 	 * keeps changing.
5870 	 */
5871 	obj = bpobj_alloc(spa->spa_meta_objset, 1 << 14, tx);
5872 	dmu_object_set_compress(spa->spa_meta_objset, obj,
5873 	    ZIO_COMPRESS_OFF, tx);
5874 	if (zap_add(spa->spa_meta_objset,
5875 	    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_SYNC_BPOBJ,
5876 	    sizeof (uint64_t), 1, &obj, tx) != 0) {
5877 		cmn_err(CE_PANIC, "failed to add bpobj");
5878 	}
5879 	VERIFY3U(0, ==, bpobj_open(&spa->spa_deferred_bpobj,
5880 	    spa->spa_meta_objset, obj));
5881 
5882 	/*
5883 	 * Generate some random noise for salted checksums to operate on.
5884 	 */
5885 	(void) random_get_pseudo_bytes(spa->spa_cksum_salt.zcs_bytes,
5886 	    sizeof (spa->spa_cksum_salt.zcs_bytes));
5887 
5888 	/*
5889 	 * Set pool properties.
5890 	 */
5891 	spa->spa_bootfs = zpool_prop_default_numeric(ZPOOL_PROP_BOOTFS);
5892 	spa->spa_delegation = zpool_prop_default_numeric(ZPOOL_PROP_DELEGATION);
5893 	spa->spa_failmode = zpool_prop_default_numeric(ZPOOL_PROP_FAILUREMODE);
5894 	spa->spa_autoexpand = zpool_prop_default_numeric(ZPOOL_PROP_AUTOEXPAND);
5895 	spa->spa_multihost = zpool_prop_default_numeric(ZPOOL_PROP_MULTIHOST);
5896 	spa->spa_autotrim = zpool_prop_default_numeric(ZPOOL_PROP_AUTOTRIM);
5897 
5898 	if (props != NULL) {
5899 		spa_configfile_set(spa, props, B_FALSE);
5900 		spa_sync_props(props, tx);
5901 	}
5902 
5903 	for (int i = 0; i < ndraid; i++)
5904 		spa_feature_incr(spa, SPA_FEATURE_DRAID, tx);
5905 
5906 	dmu_tx_commit(tx);
5907 
5908 	spa->spa_sync_on = B_TRUE;
5909 	txg_sync_start(dp);
5910 	mmp_thread_start(spa);
5911 	txg_wait_synced(dp, txg);
5912 
5913 	spa_spawn_aux_threads(spa);
5914 
5915 	spa_write_cachefile(spa, B_FALSE, B_TRUE);
5916 
5917 	/*
5918 	 * Don't count references from objsets that are already closed
5919 	 * and are making their way through the eviction process.
5920 	 */
5921 	spa_evicting_os_wait(spa);
5922 	spa->spa_minref = zfs_refcount_count(&spa->spa_refcount);
5923 	spa->spa_load_state = SPA_LOAD_NONE;
5924 
5925 	mutex_exit(&spa_namespace_lock);
5926 
5927 	return (0);
5928 }
5929 
5930 /*
5931  * Import a non-root pool into the system.
5932  */
5933 int
5934 spa_import(char *pool, nvlist_t *config, nvlist_t *props, uint64_t flags)
5935 {
5936 	spa_t *spa;
5937 	char *altroot = NULL;
5938 	spa_load_state_t state = SPA_LOAD_IMPORT;
5939 	zpool_load_policy_t policy;
5940 	spa_mode_t mode = spa_mode_global;
5941 	uint64_t readonly = B_FALSE;
5942 	int error;
5943 	nvlist_t *nvroot;
5944 	nvlist_t **spares, **l2cache;
5945 	uint_t nspares, nl2cache;
5946 
5947 	/*
5948 	 * If a pool with this name exists, return failure.
5949 	 */
5950 	mutex_enter(&spa_namespace_lock);
5951 	if (spa_lookup(pool) != NULL) {
5952 		mutex_exit(&spa_namespace_lock);
5953 		return (SET_ERROR(EEXIST));
5954 	}
5955 
5956 	/*
5957 	 * Create and initialize the spa structure.
5958 	 */
5959 	(void) nvlist_lookup_string(props,
5960 	    zpool_prop_to_name(ZPOOL_PROP_ALTROOT), &altroot);
5961 	(void) nvlist_lookup_uint64(props,
5962 	    zpool_prop_to_name(ZPOOL_PROP_READONLY), &readonly);
5963 	if (readonly)
5964 		mode = SPA_MODE_READ;
5965 	spa = spa_add(pool, config, altroot);
5966 	spa->spa_import_flags = flags;
5967 
5968 	/*
5969 	 * Verbatim import - Take a pool and insert it into the namespace
5970 	 * as if it had been loaded at boot.
5971 	 */
5972 	if (spa->spa_import_flags & ZFS_IMPORT_VERBATIM) {
5973 		if (props != NULL)
5974 			spa_configfile_set(spa, props, B_FALSE);
5975 
5976 		spa_write_cachefile(spa, B_FALSE, B_TRUE);
5977 		spa_event_notify(spa, NULL, NULL, ESC_ZFS_POOL_IMPORT);
5978 		zfs_dbgmsg("spa_import: verbatim import of %s", pool);
5979 		mutex_exit(&spa_namespace_lock);
5980 		return (0);
5981 	}
5982 
5983 	spa_activate(spa, mode);
5984 
5985 	/*
5986 	 * Don't start async tasks until we know everything is healthy.
5987 	 */
5988 	spa_async_suspend(spa);
5989 
5990 	zpool_get_load_policy(config, &policy);
5991 	if (policy.zlp_rewind & ZPOOL_DO_REWIND)
5992 		state = SPA_LOAD_RECOVER;
5993 
5994 	spa->spa_config_source = SPA_CONFIG_SRC_TRYIMPORT;
5995 
5996 	if (state != SPA_LOAD_RECOVER) {
5997 		spa->spa_last_ubsync_txg = spa->spa_load_txg = 0;
5998 		zfs_dbgmsg("spa_import: importing %s", pool);
5999 	} else {
6000 		zfs_dbgmsg("spa_import: importing %s, max_txg=%lld "
6001 		    "(RECOVERY MODE)", pool, (longlong_t)policy.zlp_txg);
6002 	}
6003 	error = spa_load_best(spa, state, policy.zlp_txg, policy.zlp_rewind);
6004 
6005 	/*
6006 	 * Propagate anything learned while loading the pool and pass it
6007 	 * back to caller (i.e. rewind info, missing devices, etc).
6008 	 */
6009 	VERIFY(nvlist_add_nvlist(config, ZPOOL_CONFIG_LOAD_INFO,
6010 	    spa->spa_load_info) == 0);
6011 
6012 	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
6013 	/*
6014 	 * Toss any existing sparelist, as it doesn't have any validity
6015 	 * anymore, and conflicts with spa_has_spare().
6016 	 */
6017 	if (spa->spa_spares.sav_config) {
6018 		nvlist_free(spa->spa_spares.sav_config);
6019 		spa->spa_spares.sav_config = NULL;
6020 		spa_load_spares(spa);
6021 	}
6022 	if (spa->spa_l2cache.sav_config) {
6023 		nvlist_free(spa->spa_l2cache.sav_config);
6024 		spa->spa_l2cache.sav_config = NULL;
6025 		spa_load_l2cache(spa);
6026 	}
6027 
6028 	VERIFY(nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE,
6029 	    &nvroot) == 0);
6030 	spa_config_exit(spa, SCL_ALL, FTAG);
6031 
6032 	if (props != NULL)
6033 		spa_configfile_set(spa, props, B_FALSE);
6034 
6035 	if (error != 0 || (props && spa_writeable(spa) &&
6036 	    (error = spa_prop_set(spa, props)))) {
6037 		spa_unload(spa);
6038 		spa_deactivate(spa);
6039 		spa_remove(spa);
6040 		mutex_exit(&spa_namespace_lock);
6041 		return (error);
6042 	}
6043 
6044 	spa_async_resume(spa);
6045 
6046 	/*
6047 	 * Override any spares and level 2 cache devices as specified by
6048 	 * the user, as these may have correct device names/devids, etc.
6049 	 */
6050 	if (nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_SPARES,
6051 	    &spares, &nspares) == 0) {
6052 		if (spa->spa_spares.sav_config)
6053 			VERIFY(nvlist_remove(spa->spa_spares.sav_config,
6054 			    ZPOOL_CONFIG_SPARES, DATA_TYPE_NVLIST_ARRAY) == 0);
6055 		else
6056 			VERIFY(nvlist_alloc(&spa->spa_spares.sav_config,
6057 			    NV_UNIQUE_NAME, KM_SLEEP) == 0);
6058 		VERIFY(nvlist_add_nvlist_array(spa->spa_spares.sav_config,
6059 		    ZPOOL_CONFIG_SPARES, spares, nspares) == 0);
6060 		spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
6061 		spa_load_spares(spa);
6062 		spa_config_exit(spa, SCL_ALL, FTAG);
6063 		spa->spa_spares.sav_sync = B_TRUE;
6064 	}
6065 	if (nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_L2CACHE,
6066 	    &l2cache, &nl2cache) == 0) {
6067 		if (spa->spa_l2cache.sav_config)
6068 			VERIFY(nvlist_remove(spa->spa_l2cache.sav_config,
6069 			    ZPOOL_CONFIG_L2CACHE, DATA_TYPE_NVLIST_ARRAY) == 0);
6070 		else
6071 			VERIFY(nvlist_alloc(&spa->spa_l2cache.sav_config,
6072 			    NV_UNIQUE_NAME, KM_SLEEP) == 0);
6073 		VERIFY(nvlist_add_nvlist_array(spa->spa_l2cache.sav_config,
6074 		    ZPOOL_CONFIG_L2CACHE, l2cache, nl2cache) == 0);
6075 		spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
6076 		spa_load_l2cache(spa);
6077 		spa_config_exit(spa, SCL_ALL, FTAG);
6078 		spa->spa_l2cache.sav_sync = B_TRUE;
6079 	}
6080 
6081 	/*
6082 	 * Check for any removed devices.
6083 	 */
6084 	if (spa->spa_autoreplace) {
6085 		spa_aux_check_removed(&spa->spa_spares);
6086 		spa_aux_check_removed(&spa->spa_l2cache);
6087 	}
6088 
6089 	if (spa_writeable(spa)) {
6090 		/*
6091 		 * Update the config cache to include the newly-imported pool.
6092 		 */
6093 		spa_config_update(spa, SPA_CONFIG_UPDATE_POOL);
6094 	}
6095 
6096 	/*
6097 	 * It's possible that the pool was expanded while it was exported.
6098 	 * We kick off an async task to handle this for us.
6099 	 */
6100 	spa_async_request(spa, SPA_ASYNC_AUTOEXPAND);
6101 
6102 	spa_history_log_version(spa, "import", NULL);
6103 
6104 	spa_event_notify(spa, NULL, NULL, ESC_ZFS_POOL_IMPORT);
6105 
6106 	mutex_exit(&spa_namespace_lock);
6107 
6108 	zvol_create_minors_recursive(pool);
6109 
6110 	return (0);
6111 }
6112 
6113 nvlist_t *
6114 spa_tryimport(nvlist_t *tryconfig)
6115 {
6116 	nvlist_t *config = NULL;
6117 	char *poolname, *cachefile;
6118 	spa_t *spa;
6119 	uint64_t state;
6120 	int error;
6121 	zpool_load_policy_t policy;
6122 
6123 	if (nvlist_lookup_string(tryconfig, ZPOOL_CONFIG_POOL_NAME, &poolname))
6124 		return (NULL);
6125 
6126 	if (nvlist_lookup_uint64(tryconfig, ZPOOL_CONFIG_POOL_STATE, &state))
6127 		return (NULL);
6128 
6129 	/*
6130 	 * Create and initialize the spa structure.
6131 	 */
6132 	mutex_enter(&spa_namespace_lock);
6133 	spa = spa_add(TRYIMPORT_NAME, tryconfig, NULL);
6134 	spa_activate(spa, SPA_MODE_READ);
6135 
6136 	/*
6137 	 * Rewind pool if a max txg was provided.
6138 	 */
6139 	zpool_get_load_policy(spa->spa_config, &policy);
6140 	if (policy.zlp_txg != UINT64_MAX) {
6141 		spa->spa_load_max_txg = policy.zlp_txg;
6142 		spa->spa_extreme_rewind = B_TRUE;
6143 		zfs_dbgmsg("spa_tryimport: importing %s, max_txg=%lld",
6144 		    poolname, (longlong_t)policy.zlp_txg);
6145 	} else {
6146 		zfs_dbgmsg("spa_tryimport: importing %s", poolname);
6147 	}
6148 
6149 	if (nvlist_lookup_string(tryconfig, ZPOOL_CONFIG_CACHEFILE, &cachefile)
6150 	    == 0) {
6151 		zfs_dbgmsg("spa_tryimport: using cachefile '%s'", cachefile);
6152 		spa->spa_config_source = SPA_CONFIG_SRC_CACHEFILE;
6153 	} else {
6154 		spa->spa_config_source = SPA_CONFIG_SRC_SCAN;
6155 	}
6156 
6157 	error = spa_load(spa, SPA_LOAD_TRYIMPORT, SPA_IMPORT_EXISTING);
6158 
6159 	/*
6160 	 * If 'tryconfig' was at least parsable, return the current config.
6161 	 */
6162 	if (spa->spa_root_vdev != NULL) {
6163 		config = spa_config_generate(spa, NULL, -1ULL, B_TRUE);
6164 		VERIFY(nvlist_add_string(config, ZPOOL_CONFIG_POOL_NAME,
6165 		    poolname) == 0);
6166 		VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_POOL_STATE,
6167 		    state) == 0);
6168 		VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_TIMESTAMP,
6169 		    spa->spa_uberblock.ub_timestamp) == 0);
6170 		VERIFY(nvlist_add_nvlist(config, ZPOOL_CONFIG_LOAD_INFO,
6171 		    spa->spa_load_info) == 0);
6172 		VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_ERRATA,
6173 		    spa->spa_errata) == 0);
6174 
6175 		/*
6176 		 * If the bootfs property exists on this pool then we
6177 		 * copy it out so that external consumers can tell which
6178 		 * pools are bootable.
6179 		 */
6180 		if ((!error || error == EEXIST) && spa->spa_bootfs) {
6181 			char *tmpname = kmem_alloc(MAXPATHLEN, KM_SLEEP);
6182 
6183 			/*
6184 			 * We have to play games with the name since the
6185 			 * pool was opened as TRYIMPORT_NAME.
6186 			 */
6187 			if (dsl_dsobj_to_dsname(spa_name(spa),
6188 			    spa->spa_bootfs, tmpname) == 0) {
6189 				char *cp;
6190 				char *dsname;
6191 
6192 				dsname = kmem_alloc(MAXPATHLEN, KM_SLEEP);
6193 
6194 				cp = strchr(tmpname, '/');
6195 				if (cp == NULL) {
6196 					(void) strlcpy(dsname, tmpname,
6197 					    MAXPATHLEN);
6198 				} else {
6199 					(void) snprintf(dsname, MAXPATHLEN,
6200 					    "%s/%s", poolname, ++cp);
6201 				}
6202 				VERIFY(nvlist_add_string(config,
6203 				    ZPOOL_CONFIG_BOOTFS, dsname) == 0);
6204 				kmem_free(dsname, MAXPATHLEN);
6205 			}
6206 			kmem_free(tmpname, MAXPATHLEN);
6207 		}
6208 
6209 		/*
6210 		 * Add the list of hot spares and level 2 cache devices.
6211 		 */
6212 		spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER);
6213 		spa_add_spares(spa, config);
6214 		spa_add_l2cache(spa, config);
6215 		spa_config_exit(spa, SCL_CONFIG, FTAG);
6216 	}
6217 
6218 	spa_unload(spa);
6219 	spa_deactivate(spa);
6220 	spa_remove(spa);
6221 	mutex_exit(&spa_namespace_lock);
6222 
6223 	return (config);
6224 }
6225 
6226 /*
6227  * Pool export/destroy
6228  *
6229  * The act of destroying or exporting a pool is very simple.  We make sure there
6230  * is no more pending I/O and any references to the pool are gone.  Then, we
6231  * update the pool state and sync all the labels to disk, removing the
6232  * configuration from the cache afterwards. If the 'hardforce' flag is set, then
6233  * we don't sync the labels or remove the configuration cache.
6234  */
6235 static int
6236 spa_export_common(const char *pool, int new_state, nvlist_t **oldconfig,
6237     boolean_t force, boolean_t hardforce)
6238 {
6239 	spa_t *spa;
6240 
6241 	if (oldconfig)
6242 		*oldconfig = NULL;
6243 
6244 	if (!(spa_mode_global & SPA_MODE_WRITE))
6245 		return (SET_ERROR(EROFS));
6246 
6247 	mutex_enter(&spa_namespace_lock);
6248 	if ((spa = spa_lookup(pool)) == NULL) {
6249 		mutex_exit(&spa_namespace_lock);
6250 		return (SET_ERROR(ENOENT));
6251 	}
6252 
6253 	if (spa->spa_is_exporting) {
6254 		/* the pool is being exported by another thread */
6255 		mutex_exit(&spa_namespace_lock);
6256 		return (SET_ERROR(ZFS_ERR_EXPORT_IN_PROGRESS));
6257 	}
6258 	spa->spa_is_exporting = B_TRUE;
6259 
6260 	/*
6261 	 * Put a hold on the pool, drop the namespace lock, stop async tasks,
6262 	 * reacquire the namespace lock, and see if we can export.
6263 	 */
6264 	spa_open_ref(spa, FTAG);
6265 	mutex_exit(&spa_namespace_lock);
6266 	spa_async_suspend(spa);
6267 	if (spa->spa_zvol_taskq) {
6268 		zvol_remove_minors(spa, spa_name(spa), B_TRUE);
6269 		taskq_wait(spa->spa_zvol_taskq);
6270 	}
6271 	mutex_enter(&spa_namespace_lock);
6272 	spa_close(spa, FTAG);
6273 
6274 	if (spa->spa_state == POOL_STATE_UNINITIALIZED)
6275 		goto export_spa;
6276 	/*
6277 	 * The pool will be in core if it's openable, in which case we can
6278 	 * modify its state.  Objsets may be open only because they're dirty,
6279 	 * so we have to force it to sync before checking spa_refcnt.
6280 	 */
6281 	if (spa->spa_sync_on) {
6282 		txg_wait_synced(spa->spa_dsl_pool, 0);
6283 		spa_evicting_os_wait(spa);
6284 	}
6285 
6286 	/*
6287 	 * A pool cannot be exported or destroyed if there are active
6288 	 * references.  If we are resetting a pool, allow references by
6289 	 * fault injection handlers.
6290 	 */
6291 	if (!spa_refcount_zero(spa) ||
6292 	    (spa->spa_inject_ref != 0 &&
6293 	    new_state != POOL_STATE_UNINITIALIZED)) {
6294 		spa_async_resume(spa);
6295 		spa->spa_is_exporting = B_FALSE;
6296 		mutex_exit(&spa_namespace_lock);
6297 		return (SET_ERROR(EBUSY));
6298 	}
6299 
6300 	if (spa->spa_sync_on) {
6301 		/*
6302 		 * A pool cannot be exported if it has an active shared spare.
6303 		 * This is to prevent other pools stealing the active spare
6304 		 * from an exported pool. At user's own will, such pool can
6305 		 * be forcedly exported.
6306 		 */
6307 		if (!force && new_state == POOL_STATE_EXPORTED &&
6308 		    spa_has_active_shared_spare(spa)) {
6309 			spa_async_resume(spa);
6310 			spa->spa_is_exporting = B_FALSE;
6311 			mutex_exit(&spa_namespace_lock);
6312 			return (SET_ERROR(EXDEV));
6313 		}
6314 
6315 		/*
6316 		 * We're about to export or destroy this pool. Make sure
6317 		 * we stop all initialization and trim activity here before
6318 		 * we set the spa_final_txg. This will ensure that all
6319 		 * dirty data resulting from the initialization is
6320 		 * committed to disk before we unload the pool.
6321 		 */
6322 		if (spa->spa_root_vdev != NULL) {
6323 			vdev_t *rvd = spa->spa_root_vdev;
6324 			vdev_initialize_stop_all(rvd, VDEV_INITIALIZE_ACTIVE);
6325 			vdev_trim_stop_all(rvd, VDEV_TRIM_ACTIVE);
6326 			vdev_autotrim_stop_all(spa);
6327 			vdev_rebuild_stop_all(spa);
6328 		}
6329 
6330 		/*
6331 		 * We want this to be reflected on every label,
6332 		 * so mark them all dirty.  spa_unload() will do the
6333 		 * final sync that pushes these changes out.
6334 		 */
6335 		if (new_state != POOL_STATE_UNINITIALIZED && !hardforce) {
6336 			spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
6337 			spa->spa_state = new_state;
6338 			spa->spa_final_txg = spa_last_synced_txg(spa) +
6339 			    TXG_DEFER_SIZE + 1;
6340 			vdev_config_dirty(spa->spa_root_vdev);
6341 			spa_config_exit(spa, SCL_ALL, FTAG);
6342 		}
6343 	}
6344 
6345 export_spa:
6346 	if (new_state == POOL_STATE_DESTROYED)
6347 		spa_event_notify(spa, NULL, NULL, ESC_ZFS_POOL_DESTROY);
6348 	else if (new_state == POOL_STATE_EXPORTED)
6349 		spa_event_notify(spa, NULL, NULL, ESC_ZFS_POOL_EXPORT);
6350 
6351 	if (spa->spa_state != POOL_STATE_UNINITIALIZED) {
6352 		spa_unload(spa);
6353 		spa_deactivate(spa);
6354 	}
6355 
6356 	if (oldconfig && spa->spa_config)
6357 		VERIFY(nvlist_dup(spa->spa_config, oldconfig, 0) == 0);
6358 
6359 	if (new_state != POOL_STATE_UNINITIALIZED) {
6360 		if (!hardforce)
6361 			spa_write_cachefile(spa, B_TRUE, B_TRUE);
6362 		spa_remove(spa);
6363 	} else {
6364 		/*
6365 		 * If spa_remove() is not called for this spa_t and
6366 		 * there is any possibility that it can be reused,
6367 		 * we make sure to reset the exporting flag.
6368 		 */
6369 		spa->spa_is_exporting = B_FALSE;
6370 	}
6371 
6372 	mutex_exit(&spa_namespace_lock);
6373 	return (0);
6374 }
6375 
6376 /*
6377  * Destroy a storage pool.
6378  */
6379 int
6380 spa_destroy(const char *pool)
6381 {
6382 	return (spa_export_common(pool, POOL_STATE_DESTROYED, NULL,
6383 	    B_FALSE, B_FALSE));
6384 }
6385 
6386 /*
6387  * Export a storage pool.
6388  */
6389 int
6390 spa_export(const char *pool, nvlist_t **oldconfig, boolean_t force,
6391     boolean_t hardforce)
6392 {
6393 	return (spa_export_common(pool, POOL_STATE_EXPORTED, oldconfig,
6394 	    force, hardforce));
6395 }
6396 
6397 /*
6398  * Similar to spa_export(), this unloads the spa_t without actually removing it
6399  * from the namespace in any way.
6400  */
6401 int
6402 spa_reset(const char *pool)
6403 {
6404 	return (spa_export_common(pool, POOL_STATE_UNINITIALIZED, NULL,
6405 	    B_FALSE, B_FALSE));
6406 }
6407 
6408 /*
6409  * ==========================================================================
6410  * Device manipulation
6411  * ==========================================================================
6412  */
6413 
6414 /*
6415  * This is called as a synctask to increment the draid feature flag
6416  */
6417 static void
6418 spa_draid_feature_incr(void *arg, dmu_tx_t *tx)
6419 {
6420 	spa_t *spa = dmu_tx_pool(tx)->dp_spa;
6421 	int draid = (int)(uintptr_t)arg;
6422 
6423 	for (int c = 0; c < draid; c++)
6424 		spa_feature_incr(spa, SPA_FEATURE_DRAID, tx);
6425 }
6426 
6427 /*
6428  * Add a device to a storage pool.
6429  */
6430 int
6431 spa_vdev_add(spa_t *spa, nvlist_t *nvroot)
6432 {
6433 	uint64_t txg, ndraid = 0;
6434 	int error;
6435 	vdev_t *rvd = spa->spa_root_vdev;
6436 	vdev_t *vd, *tvd;
6437 	nvlist_t **spares, **l2cache;
6438 	uint_t nspares, nl2cache;
6439 
6440 	ASSERT(spa_writeable(spa));
6441 
6442 	txg = spa_vdev_enter(spa);
6443 
6444 	if ((error = spa_config_parse(spa, &vd, nvroot, NULL, 0,
6445 	    VDEV_ALLOC_ADD)) != 0)
6446 		return (spa_vdev_exit(spa, NULL, txg, error));
6447 
6448 	spa->spa_pending_vdev = vd;	/* spa_vdev_exit() will clear this */
6449 
6450 	if (nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_SPARES, &spares,
6451 	    &nspares) != 0)
6452 		nspares = 0;
6453 
6454 	if (nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_L2CACHE, &l2cache,
6455 	    &nl2cache) != 0)
6456 		nl2cache = 0;
6457 
6458 	if (vd->vdev_children == 0 && nspares == 0 && nl2cache == 0)
6459 		return (spa_vdev_exit(spa, vd, txg, EINVAL));
6460 
6461 	if (vd->vdev_children != 0 &&
6462 	    (error = vdev_create(vd, txg, B_FALSE)) != 0) {
6463 		return (spa_vdev_exit(spa, vd, txg, error));
6464 	}
6465 
6466 	/*
6467 	 * The virtual dRAID spares must be added after vdev tree is created
6468 	 * and the vdev guids are generated.  The guid of their assoicated
6469 	 * dRAID is stored in the config and used when opening the spare.
6470 	 */
6471 	if ((error = vdev_draid_spare_create(nvroot, vd, &ndraid,
6472 	    rvd->vdev_children)) == 0) {
6473 		if (ndraid > 0 && nvlist_lookup_nvlist_array(nvroot,
6474 		    ZPOOL_CONFIG_SPARES, &spares, &nspares) != 0)
6475 			nspares = 0;
6476 	} else {
6477 		return (spa_vdev_exit(spa, vd, txg, error));
6478 	}
6479 
6480 	/*
6481 	 * We must validate the spares and l2cache devices after checking the
6482 	 * children.  Otherwise, vdev_inuse() will blindly overwrite the spare.
6483 	 */
6484 	if ((error = spa_validate_aux(spa, nvroot, txg, VDEV_ALLOC_ADD)) != 0)
6485 		return (spa_vdev_exit(spa, vd, txg, error));
6486 
6487 	/*
6488 	 * If we are in the middle of a device removal, we can only add
6489 	 * devices which match the existing devices in the pool.
6490 	 * If we are in the middle of a removal, or have some indirect
6491 	 * vdevs, we can not add raidz or dRAID top levels.
6492 	 */
6493 	if (spa->spa_vdev_removal != NULL ||
6494 	    spa->spa_removing_phys.sr_prev_indirect_vdev != -1) {
6495 		for (int c = 0; c < vd->vdev_children; c++) {
6496 			tvd = vd->vdev_child[c];
6497 			if (spa->spa_vdev_removal != NULL &&
6498 			    tvd->vdev_ashift != spa->spa_max_ashift) {
6499 				return (spa_vdev_exit(spa, vd, txg, EINVAL));
6500 			}
6501 			/* Fail if top level vdev is raidz or a dRAID */
6502 			if (vdev_get_nparity(tvd) != 0)
6503 				return (spa_vdev_exit(spa, vd, txg, EINVAL));
6504 
6505 			/*
6506 			 * Need the top level mirror to be
6507 			 * a mirror of leaf vdevs only
6508 			 */
6509 			if (tvd->vdev_ops == &vdev_mirror_ops) {
6510 				for (uint64_t cid = 0;
6511 				    cid < tvd->vdev_children; cid++) {
6512 					vdev_t *cvd = tvd->vdev_child[cid];
6513 					if (!cvd->vdev_ops->vdev_op_leaf) {
6514 						return (spa_vdev_exit(spa, vd,
6515 						    txg, EINVAL));
6516 					}
6517 				}
6518 			}
6519 		}
6520 	}
6521 
6522 	for (int c = 0; c < vd->vdev_children; c++) {
6523 		tvd = vd->vdev_child[c];
6524 		vdev_remove_child(vd, tvd);
6525 		tvd->vdev_id = rvd->vdev_children;
6526 		vdev_add_child(rvd, tvd);
6527 		vdev_config_dirty(tvd);
6528 	}
6529 
6530 	if (nspares != 0) {
6531 		spa_set_aux_vdevs(&spa->spa_spares, spares, nspares,
6532 		    ZPOOL_CONFIG_SPARES);
6533 		spa_load_spares(spa);
6534 		spa->spa_spares.sav_sync = B_TRUE;
6535 	}
6536 
6537 	if (nl2cache != 0) {
6538 		spa_set_aux_vdevs(&spa->spa_l2cache, l2cache, nl2cache,
6539 		    ZPOOL_CONFIG_L2CACHE);
6540 		spa_load_l2cache(spa);
6541 		spa->spa_l2cache.sav_sync = B_TRUE;
6542 	}
6543 
6544 	/*
6545 	 * We can't increment a feature while holding spa_vdev so we
6546 	 * have to do it in a synctask.
6547 	 */
6548 	if (ndraid != 0) {
6549 		dmu_tx_t *tx;
6550 
6551 		tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg);
6552 		dsl_sync_task_nowait(spa->spa_dsl_pool, spa_draid_feature_incr,
6553 		    (void *)(uintptr_t)ndraid, tx);
6554 		dmu_tx_commit(tx);
6555 	}
6556 
6557 	/*
6558 	 * We have to be careful when adding new vdevs to an existing pool.
6559 	 * If other threads start allocating from these vdevs before we
6560 	 * sync the config cache, and we lose power, then upon reboot we may
6561 	 * fail to open the pool because there are DVAs that the config cache
6562 	 * can't translate.  Therefore, we first add the vdevs without
6563 	 * initializing metaslabs; sync the config cache (via spa_vdev_exit());
6564 	 * and then let spa_config_update() initialize the new metaslabs.
6565 	 *
6566 	 * spa_load() checks for added-but-not-initialized vdevs, so that
6567 	 * if we lose power at any point in this sequence, the remaining
6568 	 * steps will be completed the next time we load the pool.
6569 	 */
6570 	(void) spa_vdev_exit(spa, vd, txg, 0);
6571 
6572 	mutex_enter(&spa_namespace_lock);
6573 	spa_config_update(spa, SPA_CONFIG_UPDATE_POOL);
6574 	spa_event_notify(spa, NULL, NULL, ESC_ZFS_VDEV_ADD);
6575 	mutex_exit(&spa_namespace_lock);
6576 
6577 	return (0);
6578 }
6579 
6580 /*
6581  * Attach a device to a mirror.  The arguments are the path to any device
6582  * in the mirror, and the nvroot for the new device.  If the path specifies
6583  * a device that is not mirrored, we automatically insert the mirror vdev.
6584  *
6585  * If 'replacing' is specified, the new device is intended to replace the
6586  * existing device; in this case the two devices are made into their own
6587  * mirror using the 'replacing' vdev, which is functionally identical to
6588  * the mirror vdev (it actually reuses all the same ops) but has a few
6589  * extra rules: you can't attach to it after it's been created, and upon
6590  * completion of resilvering, the first disk (the one being replaced)
6591  * is automatically detached.
6592  *
6593  * If 'rebuild' is specified, then sequential reconstruction (a.ka. rebuild)
6594  * should be performed instead of traditional healing reconstruction.  From
6595  * an administrators perspective these are both resilver operations.
6596  */
6597 int
6598 spa_vdev_attach(spa_t *spa, uint64_t guid, nvlist_t *nvroot, int replacing,
6599     int rebuild)
6600 {
6601 	uint64_t txg, dtl_max_txg;
6602 	vdev_t *rvd = spa->spa_root_vdev;
6603 	vdev_t *oldvd, *newvd, *newrootvd, *pvd, *tvd;
6604 	vdev_ops_t *pvops;
6605 	char *oldvdpath, *newvdpath;
6606 	int newvd_isspare;
6607 	int error;
6608 
6609 	ASSERT(spa_writeable(spa));
6610 
6611 	txg = spa_vdev_enter(spa);
6612 
6613 	oldvd = spa_lookup_by_guid(spa, guid, B_FALSE);
6614 
6615 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
6616 	if (spa_feature_is_active(spa, SPA_FEATURE_POOL_CHECKPOINT)) {
6617 		error = (spa_has_checkpoint(spa)) ?
6618 		    ZFS_ERR_CHECKPOINT_EXISTS : ZFS_ERR_DISCARDING_CHECKPOINT;
6619 		return (spa_vdev_exit(spa, NULL, txg, error));
6620 	}
6621 
6622 	if (rebuild) {
6623 		if (!spa_feature_is_enabled(spa, SPA_FEATURE_DEVICE_REBUILD))
6624 			return (spa_vdev_exit(spa, NULL, txg, ENOTSUP));
6625 
6626 		if (dsl_scan_resilvering(spa_get_dsl(spa)))
6627 			return (spa_vdev_exit(spa, NULL, txg,
6628 			    ZFS_ERR_RESILVER_IN_PROGRESS));
6629 	} else {
6630 		if (vdev_rebuild_active(rvd))
6631 			return (spa_vdev_exit(spa, NULL, txg,
6632 			    ZFS_ERR_REBUILD_IN_PROGRESS));
6633 	}
6634 
6635 	if (spa->spa_vdev_removal != NULL)
6636 		return (spa_vdev_exit(spa, NULL, txg, EBUSY));
6637 
6638 	if (oldvd == NULL)
6639 		return (spa_vdev_exit(spa, NULL, txg, ENODEV));
6640 
6641 	if (!oldvd->vdev_ops->vdev_op_leaf)
6642 		return (spa_vdev_exit(spa, NULL, txg, ENOTSUP));
6643 
6644 	pvd = oldvd->vdev_parent;
6645 
6646 	if ((error = spa_config_parse(spa, &newrootvd, nvroot, NULL, 0,
6647 	    VDEV_ALLOC_ATTACH)) != 0)
6648 		return (spa_vdev_exit(spa, NULL, txg, EINVAL));
6649 
6650 	if (newrootvd->vdev_children != 1)
6651 		return (spa_vdev_exit(spa, newrootvd, txg, EINVAL));
6652 
6653 	newvd = newrootvd->vdev_child[0];
6654 
6655 	if (!newvd->vdev_ops->vdev_op_leaf)
6656 		return (spa_vdev_exit(spa, newrootvd, txg, EINVAL));
6657 
6658 	if ((error = vdev_create(newrootvd, txg, replacing)) != 0)
6659 		return (spa_vdev_exit(spa, newrootvd, txg, error));
6660 
6661 	/*
6662 	 * Spares can't replace logs
6663 	 */
6664 	if (oldvd->vdev_top->vdev_islog && newvd->vdev_isspare)
6665 		return (spa_vdev_exit(spa, newrootvd, txg, ENOTSUP));
6666 
6667 	/*
6668 	 * A dRAID spare can only replace a child of its parent dRAID vdev.
6669 	 */
6670 	if (newvd->vdev_ops == &vdev_draid_spare_ops &&
6671 	    oldvd->vdev_top != vdev_draid_spare_get_parent(newvd)) {
6672 		return (spa_vdev_exit(spa, newrootvd, txg, ENOTSUP));
6673 	}
6674 
6675 	if (rebuild) {
6676 		/*
6677 		 * For rebuilds, the top vdev must support reconstruction
6678 		 * using only space maps.  This means the only allowable
6679 		 * vdevs types are the root vdev, a mirror, or dRAID.
6680 		 */
6681 		tvd = pvd;
6682 		if (pvd->vdev_top != NULL)
6683 			tvd = pvd->vdev_top;
6684 
6685 		if (tvd->vdev_ops != &vdev_mirror_ops &&
6686 		    tvd->vdev_ops != &vdev_root_ops &&
6687 		    tvd->vdev_ops != &vdev_draid_ops) {
6688 			return (spa_vdev_exit(spa, newrootvd, txg, ENOTSUP));
6689 		}
6690 	}
6691 
6692 	if (!replacing) {
6693 		/*
6694 		 * For attach, the only allowable parent is a mirror or the root
6695 		 * vdev.
6696 		 */
6697 		if (pvd->vdev_ops != &vdev_mirror_ops &&
6698 		    pvd->vdev_ops != &vdev_root_ops)
6699 			return (spa_vdev_exit(spa, newrootvd, txg, ENOTSUP));
6700 
6701 		pvops = &vdev_mirror_ops;
6702 	} else {
6703 		/*
6704 		 * Active hot spares can only be replaced by inactive hot
6705 		 * spares.
6706 		 */
6707 		if (pvd->vdev_ops == &vdev_spare_ops &&
6708 		    oldvd->vdev_isspare &&
6709 		    !spa_has_spare(spa, newvd->vdev_guid))
6710 			return (spa_vdev_exit(spa, newrootvd, txg, ENOTSUP));
6711 
6712 		/*
6713 		 * If the source is a hot spare, and the parent isn't already a
6714 		 * spare, then we want to create a new hot spare.  Otherwise, we
6715 		 * want to create a replacing vdev.  The user is not allowed to
6716 		 * attach to a spared vdev child unless the 'isspare' state is
6717 		 * the same (spare replaces spare, non-spare replaces
6718 		 * non-spare).
6719 		 */
6720 		if (pvd->vdev_ops == &vdev_replacing_ops &&
6721 		    spa_version(spa) < SPA_VERSION_MULTI_REPLACE) {
6722 			return (spa_vdev_exit(spa, newrootvd, txg, ENOTSUP));
6723 		} else if (pvd->vdev_ops == &vdev_spare_ops &&
6724 		    newvd->vdev_isspare != oldvd->vdev_isspare) {
6725 			return (spa_vdev_exit(spa, newrootvd, txg, ENOTSUP));
6726 		}
6727 
6728 		if (newvd->vdev_isspare)
6729 			pvops = &vdev_spare_ops;
6730 		else
6731 			pvops = &vdev_replacing_ops;
6732 	}
6733 
6734 	/*
6735 	 * Make sure the new device is big enough.
6736 	 */
6737 	if (newvd->vdev_asize < vdev_get_min_asize(oldvd))
6738 		return (spa_vdev_exit(spa, newrootvd, txg, EOVERFLOW));
6739 
6740 	/*
6741 	 * The new device cannot have a higher alignment requirement
6742 	 * than the top-level vdev.
6743 	 */
6744 	if (newvd->vdev_ashift > oldvd->vdev_top->vdev_ashift)
6745 		return (spa_vdev_exit(spa, newrootvd, txg, ENOTSUP));
6746 
6747 	/*
6748 	 * If this is an in-place replacement, update oldvd's path and devid
6749 	 * to make it distinguishable from newvd, and unopenable from now on.
6750 	 */
6751 	if (strcmp(oldvd->vdev_path, newvd->vdev_path) == 0) {
6752 		spa_strfree(oldvd->vdev_path);
6753 		oldvd->vdev_path = kmem_alloc(strlen(newvd->vdev_path) + 5,
6754 		    KM_SLEEP);
6755 		(void) snprintf(oldvd->vdev_path, strlen(newvd->vdev_path) + 5,
6756 		    "%s/%s", newvd->vdev_path, "old");
6757 		if (oldvd->vdev_devid != NULL) {
6758 			spa_strfree(oldvd->vdev_devid);
6759 			oldvd->vdev_devid = NULL;
6760 		}
6761 	}
6762 
6763 	/*
6764 	 * If the parent is not a mirror, or if we're replacing, insert the new
6765 	 * mirror/replacing/spare vdev above oldvd.
6766 	 */
6767 	if (pvd->vdev_ops != pvops)
6768 		pvd = vdev_add_parent(oldvd, pvops);
6769 
6770 	ASSERT(pvd->vdev_top->vdev_parent == rvd);
6771 	ASSERT(pvd->vdev_ops == pvops);
6772 	ASSERT(oldvd->vdev_parent == pvd);
6773 
6774 	/*
6775 	 * Extract the new device from its root and add it to pvd.
6776 	 */
6777 	vdev_remove_child(newrootvd, newvd);
6778 	newvd->vdev_id = pvd->vdev_children;
6779 	newvd->vdev_crtxg = oldvd->vdev_crtxg;
6780 	vdev_add_child(pvd, newvd);
6781 
6782 	/*
6783 	 * Reevaluate the parent vdev state.
6784 	 */
6785 	vdev_propagate_state(pvd);
6786 
6787 	tvd = newvd->vdev_top;
6788 	ASSERT(pvd->vdev_top == tvd);
6789 	ASSERT(tvd->vdev_parent == rvd);
6790 
6791 	vdev_config_dirty(tvd);
6792 
6793 	/*
6794 	 * Set newvd's DTL to [TXG_INITIAL, dtl_max_txg) so that we account
6795 	 * for any dmu_sync-ed blocks.  It will propagate upward when
6796 	 * spa_vdev_exit() calls vdev_dtl_reassess().
6797 	 */
6798 	dtl_max_txg = txg + TXG_CONCURRENT_STATES;
6799 
6800 	vdev_dtl_dirty(newvd, DTL_MISSING,
6801 	    TXG_INITIAL, dtl_max_txg - TXG_INITIAL);
6802 
6803 	if (newvd->vdev_isspare) {
6804 		spa_spare_activate(newvd);
6805 		spa_event_notify(spa, newvd, NULL, ESC_ZFS_VDEV_SPARE);
6806 	}
6807 
6808 	oldvdpath = spa_strdup(oldvd->vdev_path);
6809 	newvdpath = spa_strdup(newvd->vdev_path);
6810 	newvd_isspare = newvd->vdev_isspare;
6811 
6812 	/*
6813 	 * Mark newvd's DTL dirty in this txg.
6814 	 */
6815 	vdev_dirty(tvd, VDD_DTL, newvd, txg);
6816 
6817 	/*
6818 	 * Schedule the resilver or rebuild to restart in the future. We do
6819 	 * this to ensure that dmu_sync-ed blocks have been stitched into the
6820 	 * respective datasets.
6821 	 */
6822 	if (rebuild) {
6823 		newvd->vdev_rebuild_txg = txg;
6824 
6825 		vdev_rebuild(tvd);
6826 	} else {
6827 		newvd->vdev_resilver_txg = txg;
6828 
6829 		if (dsl_scan_resilvering(spa_get_dsl(spa)) &&
6830 		    spa_feature_is_enabled(spa, SPA_FEATURE_RESILVER_DEFER)) {
6831 			vdev_defer_resilver(newvd);
6832 		} else {
6833 			dsl_scan_restart_resilver(spa->spa_dsl_pool,
6834 			    dtl_max_txg);
6835 		}
6836 	}
6837 
6838 	if (spa->spa_bootfs)
6839 		spa_event_notify(spa, newvd, NULL, ESC_ZFS_BOOTFS_VDEV_ATTACH);
6840 
6841 	spa_event_notify(spa, newvd, NULL, ESC_ZFS_VDEV_ATTACH);
6842 
6843 	/*
6844 	 * Commit the config
6845 	 */
6846 	(void) spa_vdev_exit(spa, newrootvd, dtl_max_txg, 0);
6847 
6848 	spa_history_log_internal(spa, "vdev attach", NULL,
6849 	    "%s vdev=%s %s vdev=%s",
6850 	    replacing && newvd_isspare ? "spare in" :
6851 	    replacing ? "replace" : "attach", newvdpath,
6852 	    replacing ? "for" : "to", oldvdpath);
6853 
6854 	spa_strfree(oldvdpath);
6855 	spa_strfree(newvdpath);
6856 
6857 	return (0);
6858 }
6859 
6860 /*
6861  * Detach a device from a mirror or replacing vdev.
6862  *
6863  * If 'replace_done' is specified, only detach if the parent
6864  * is a replacing vdev.
6865  */
6866 int
6867 spa_vdev_detach(spa_t *spa, uint64_t guid, uint64_t pguid, int replace_done)
6868 {
6869 	uint64_t txg;
6870 	int error;
6871 	vdev_t *rvd __maybe_unused = spa->spa_root_vdev;
6872 	vdev_t *vd, *pvd, *cvd, *tvd;
6873 	boolean_t unspare = B_FALSE;
6874 	uint64_t unspare_guid = 0;
6875 	char *vdpath;
6876 
6877 	ASSERT(spa_writeable(spa));
6878 
6879 	txg = spa_vdev_detach_enter(spa, guid);
6880 
6881 	vd = spa_lookup_by_guid(spa, guid, B_FALSE);
6882 
6883 	/*
6884 	 * Besides being called directly from the userland through the
6885 	 * ioctl interface, spa_vdev_detach() can be potentially called
6886 	 * at the end of spa_vdev_resilver_done().
6887 	 *
6888 	 * In the regular case, when we have a checkpoint this shouldn't
6889 	 * happen as we never empty the DTLs of a vdev during the scrub
6890 	 * [see comment in dsl_scan_done()]. Thus spa_vdev_resilvering_done()
6891 	 * should never get here when we have a checkpoint.
6892 	 *
6893 	 * That said, even in a case when we checkpoint the pool exactly
6894 	 * as spa_vdev_resilver_done() calls this function everything
6895 	 * should be fine as the resilver will return right away.
6896 	 */
6897 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
6898 	if (spa_feature_is_active(spa, SPA_FEATURE_POOL_CHECKPOINT)) {
6899 		error = (spa_has_checkpoint(spa)) ?
6900 		    ZFS_ERR_CHECKPOINT_EXISTS : ZFS_ERR_DISCARDING_CHECKPOINT;
6901 		return (spa_vdev_exit(spa, NULL, txg, error));
6902 	}
6903 
6904 	if (vd == NULL)
6905 		return (spa_vdev_exit(spa, NULL, txg, ENODEV));
6906 
6907 	if (!vd->vdev_ops->vdev_op_leaf)
6908 		return (spa_vdev_exit(spa, NULL, txg, ENOTSUP));
6909 
6910 	pvd = vd->vdev_parent;
6911 
6912 	/*
6913 	 * If the parent/child relationship is not as expected, don't do it.
6914 	 * Consider M(A,R(B,C)) -- that is, a mirror of A with a replacing
6915 	 * vdev that's replacing B with C.  The user's intent in replacing
6916 	 * is to go from M(A,B) to M(A,C).  If the user decides to cancel
6917 	 * the replace by detaching C, the expected behavior is to end up
6918 	 * M(A,B).  But suppose that right after deciding to detach C,
6919 	 * the replacement of B completes.  We would have M(A,C), and then
6920 	 * ask to detach C, which would leave us with just A -- not what
6921 	 * the user wanted.  To prevent this, we make sure that the
6922 	 * parent/child relationship hasn't changed -- in this example,
6923 	 * that C's parent is still the replacing vdev R.
6924 	 */
6925 	if (pvd->vdev_guid != pguid && pguid != 0)
6926 		return (spa_vdev_exit(spa, NULL, txg, EBUSY));
6927 
6928 	/*
6929 	 * Only 'replacing' or 'spare' vdevs can be replaced.
6930 	 */
6931 	if (replace_done && pvd->vdev_ops != &vdev_replacing_ops &&
6932 	    pvd->vdev_ops != &vdev_spare_ops)
6933 		return (spa_vdev_exit(spa, NULL, txg, ENOTSUP));
6934 
6935 	ASSERT(pvd->vdev_ops != &vdev_spare_ops ||
6936 	    spa_version(spa) >= SPA_VERSION_SPARES);
6937 
6938 	/*
6939 	 * Only mirror, replacing, and spare vdevs support detach.
6940 	 */
6941 	if (pvd->vdev_ops != &vdev_replacing_ops &&
6942 	    pvd->vdev_ops != &vdev_mirror_ops &&
6943 	    pvd->vdev_ops != &vdev_spare_ops)
6944 		return (spa_vdev_exit(spa, NULL, txg, ENOTSUP));
6945 
6946 	/*
6947 	 * If this device has the only valid copy of some data,
6948 	 * we cannot safely detach it.
6949 	 */
6950 	if (vdev_dtl_required(vd))
6951 		return (spa_vdev_exit(spa, NULL, txg, EBUSY));
6952 
6953 	ASSERT(pvd->vdev_children >= 2);
6954 
6955 	/*
6956 	 * If we are detaching the second disk from a replacing vdev, then
6957 	 * check to see if we changed the original vdev's path to have "/old"
6958 	 * at the end in spa_vdev_attach().  If so, undo that change now.
6959 	 */
6960 	if (pvd->vdev_ops == &vdev_replacing_ops && vd->vdev_id > 0 &&
6961 	    vd->vdev_path != NULL) {
6962 		size_t len = strlen(vd->vdev_path);
6963 
6964 		for (int c = 0; c < pvd->vdev_children; c++) {
6965 			cvd = pvd->vdev_child[c];
6966 
6967 			if (cvd == vd || cvd->vdev_path == NULL)
6968 				continue;
6969 
6970 			if (strncmp(cvd->vdev_path, vd->vdev_path, len) == 0 &&
6971 			    strcmp(cvd->vdev_path + len, "/old") == 0) {
6972 				spa_strfree(cvd->vdev_path);
6973 				cvd->vdev_path = spa_strdup(vd->vdev_path);
6974 				break;
6975 			}
6976 		}
6977 	}
6978 
6979 	/*
6980 	 * If we are detaching the original disk from a normal spare, then it
6981 	 * implies that the spare should become a real disk, and be removed
6982 	 * from the active spare list for the pool.  dRAID spares on the
6983 	 * other hand are coupled to the pool and thus should never be removed
6984 	 * from the spares list.
6985 	 */
6986 	if (pvd->vdev_ops == &vdev_spare_ops && vd->vdev_id == 0) {
6987 		vdev_t *last_cvd = pvd->vdev_child[pvd->vdev_children - 1];
6988 
6989 		if (last_cvd->vdev_isspare &&
6990 		    last_cvd->vdev_ops != &vdev_draid_spare_ops) {
6991 			unspare = B_TRUE;
6992 		}
6993 	}
6994 
6995 	/*
6996 	 * Erase the disk labels so the disk can be used for other things.
6997 	 * This must be done after all other error cases are handled,
6998 	 * but before we disembowel vd (so we can still do I/O to it).
6999 	 * But if we can't do it, don't treat the error as fatal --
7000 	 * it may be that the unwritability of the disk is the reason
7001 	 * it's being detached!
7002 	 */
7003 	error = vdev_label_init(vd, 0, VDEV_LABEL_REMOVE);
7004 
7005 	/*
7006 	 * Remove vd from its parent and compact the parent's children.
7007 	 */
7008 	vdev_remove_child(pvd, vd);
7009 	vdev_compact_children(pvd);
7010 
7011 	/*
7012 	 * Remember one of the remaining children so we can get tvd below.
7013 	 */
7014 	cvd = pvd->vdev_child[pvd->vdev_children - 1];
7015 
7016 	/*
7017 	 * If we need to remove the remaining child from the list of hot spares,
7018 	 * do it now, marking the vdev as no longer a spare in the process.
7019 	 * We must do this before vdev_remove_parent(), because that can
7020 	 * change the GUID if it creates a new toplevel GUID.  For a similar
7021 	 * reason, we must remove the spare now, in the same txg as the detach;
7022 	 * otherwise someone could attach a new sibling, change the GUID, and
7023 	 * the subsequent attempt to spa_vdev_remove(unspare_guid) would fail.
7024 	 */
7025 	if (unspare) {
7026 		ASSERT(cvd->vdev_isspare);
7027 		spa_spare_remove(cvd);
7028 		unspare_guid = cvd->vdev_guid;
7029 		(void) spa_vdev_remove(spa, unspare_guid, B_TRUE);
7030 		cvd->vdev_unspare = B_TRUE;
7031 	}
7032 
7033 	/*
7034 	 * If the parent mirror/replacing vdev only has one child,
7035 	 * the parent is no longer needed.  Remove it from the tree.
7036 	 */
7037 	if (pvd->vdev_children == 1) {
7038 		if (pvd->vdev_ops == &vdev_spare_ops)
7039 			cvd->vdev_unspare = B_FALSE;
7040 		vdev_remove_parent(cvd);
7041 	}
7042 
7043 	/*
7044 	 * We don't set tvd until now because the parent we just removed
7045 	 * may have been the previous top-level vdev.
7046 	 */
7047 	tvd = cvd->vdev_top;
7048 	ASSERT(tvd->vdev_parent == rvd);
7049 
7050 	/*
7051 	 * Reevaluate the parent vdev state.
7052 	 */
7053 	vdev_propagate_state(cvd);
7054 
7055 	/*
7056 	 * If the 'autoexpand' property is set on the pool then automatically
7057 	 * try to expand the size of the pool. For example if the device we
7058 	 * just detached was smaller than the others, it may be possible to
7059 	 * add metaslabs (i.e. grow the pool). We need to reopen the vdev
7060 	 * first so that we can obtain the updated sizes of the leaf vdevs.
7061 	 */
7062 	if (spa->spa_autoexpand) {
7063 		vdev_reopen(tvd);
7064 		vdev_expand(tvd, txg);
7065 	}
7066 
7067 	vdev_config_dirty(tvd);
7068 
7069 	/*
7070 	 * Mark vd's DTL as dirty in this txg.  vdev_dtl_sync() will see that
7071 	 * vd->vdev_detached is set and free vd's DTL object in syncing context.
7072 	 * But first make sure we're not on any *other* txg's DTL list, to
7073 	 * prevent vd from being accessed after it's freed.
7074 	 */
7075 	vdpath = spa_strdup(vd->vdev_path ? vd->vdev_path : "none");
7076 	for (int t = 0; t < TXG_SIZE; t++)
7077 		(void) txg_list_remove_this(&tvd->vdev_dtl_list, vd, t);
7078 	vd->vdev_detached = B_TRUE;
7079 	vdev_dirty(tvd, VDD_DTL, vd, txg);
7080 
7081 	spa_event_notify(spa, vd, NULL, ESC_ZFS_VDEV_REMOVE);
7082 	spa_notify_waiters(spa);
7083 
7084 	/* hang on to the spa before we release the lock */
7085 	spa_open_ref(spa, FTAG);
7086 
7087 	error = spa_vdev_exit(spa, vd, txg, 0);
7088 
7089 	spa_history_log_internal(spa, "detach", NULL,
7090 	    "vdev=%s", vdpath);
7091 	spa_strfree(vdpath);
7092 
7093 	/*
7094 	 * If this was the removal of the original device in a hot spare vdev,
7095 	 * then we want to go through and remove the device from the hot spare
7096 	 * list of every other pool.
7097 	 */
7098 	if (unspare) {
7099 		spa_t *altspa = NULL;
7100 
7101 		mutex_enter(&spa_namespace_lock);
7102 		while ((altspa = spa_next(altspa)) != NULL) {
7103 			if (altspa->spa_state != POOL_STATE_ACTIVE ||
7104 			    altspa == spa)
7105 				continue;
7106 
7107 			spa_open_ref(altspa, FTAG);
7108 			mutex_exit(&spa_namespace_lock);
7109 			(void) spa_vdev_remove(altspa, unspare_guid, B_TRUE);
7110 			mutex_enter(&spa_namespace_lock);
7111 			spa_close(altspa, FTAG);
7112 		}
7113 		mutex_exit(&spa_namespace_lock);
7114 
7115 		/* search the rest of the vdevs for spares to remove */
7116 		spa_vdev_resilver_done(spa);
7117 	}
7118 
7119 	/* all done with the spa; OK to release */
7120 	mutex_enter(&spa_namespace_lock);
7121 	spa_close(spa, FTAG);
7122 	mutex_exit(&spa_namespace_lock);
7123 
7124 	return (error);
7125 }
7126 
7127 static int
7128 spa_vdev_initialize_impl(spa_t *spa, uint64_t guid, uint64_t cmd_type,
7129     list_t *vd_list)
7130 {
7131 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
7132 
7133 	spa_config_enter(spa, SCL_CONFIG | SCL_STATE, FTAG, RW_READER);
7134 
7135 	/* Look up vdev and ensure it's a leaf. */
7136 	vdev_t *vd = spa_lookup_by_guid(spa, guid, B_FALSE);
7137 	if (vd == NULL || vd->vdev_detached) {
7138 		spa_config_exit(spa, SCL_CONFIG | SCL_STATE, FTAG);
7139 		return (SET_ERROR(ENODEV));
7140 	} else if (!vd->vdev_ops->vdev_op_leaf || !vdev_is_concrete(vd)) {
7141 		spa_config_exit(spa, SCL_CONFIG | SCL_STATE, FTAG);
7142 		return (SET_ERROR(EINVAL));
7143 	} else if (!vdev_writeable(vd)) {
7144 		spa_config_exit(spa, SCL_CONFIG | SCL_STATE, FTAG);
7145 		return (SET_ERROR(EROFS));
7146 	}
7147 	mutex_enter(&vd->vdev_initialize_lock);
7148 	spa_config_exit(spa, SCL_CONFIG | SCL_STATE, FTAG);
7149 
7150 	/*
7151 	 * When we activate an initialize action we check to see
7152 	 * if the vdev_initialize_thread is NULL. We do this instead
7153 	 * of using the vdev_initialize_state since there might be
7154 	 * a previous initialization process which has completed but
7155 	 * the thread is not exited.
7156 	 */
7157 	if (cmd_type == POOL_INITIALIZE_START &&
7158 	    (vd->vdev_initialize_thread != NULL ||
7159 	    vd->vdev_top->vdev_removing)) {
7160 		mutex_exit(&vd->vdev_initialize_lock);
7161 		return (SET_ERROR(EBUSY));
7162 	} else if (cmd_type == POOL_INITIALIZE_CANCEL &&
7163 	    (vd->vdev_initialize_state != VDEV_INITIALIZE_ACTIVE &&
7164 	    vd->vdev_initialize_state != VDEV_INITIALIZE_SUSPENDED)) {
7165 		mutex_exit(&vd->vdev_initialize_lock);
7166 		return (SET_ERROR(ESRCH));
7167 	} else if (cmd_type == POOL_INITIALIZE_SUSPEND &&
7168 	    vd->vdev_initialize_state != VDEV_INITIALIZE_ACTIVE) {
7169 		mutex_exit(&vd->vdev_initialize_lock);
7170 		return (SET_ERROR(ESRCH));
7171 	}
7172 
7173 	switch (cmd_type) {
7174 	case POOL_INITIALIZE_START:
7175 		vdev_initialize(vd);
7176 		break;
7177 	case POOL_INITIALIZE_CANCEL:
7178 		vdev_initialize_stop(vd, VDEV_INITIALIZE_CANCELED, vd_list);
7179 		break;
7180 	case POOL_INITIALIZE_SUSPEND:
7181 		vdev_initialize_stop(vd, VDEV_INITIALIZE_SUSPENDED, vd_list);
7182 		break;
7183 	default:
7184 		panic("invalid cmd_type %llu", (unsigned long long)cmd_type);
7185 	}
7186 	mutex_exit(&vd->vdev_initialize_lock);
7187 
7188 	return (0);
7189 }
7190 
7191 int
7192 spa_vdev_initialize(spa_t *spa, nvlist_t *nv, uint64_t cmd_type,
7193     nvlist_t *vdev_errlist)
7194 {
7195 	int total_errors = 0;
7196 	list_t vd_list;
7197 
7198 	list_create(&vd_list, sizeof (vdev_t),
7199 	    offsetof(vdev_t, vdev_initialize_node));
7200 
7201 	/*
7202 	 * We hold the namespace lock through the whole function
7203 	 * to prevent any changes to the pool while we're starting or
7204 	 * stopping initialization. The config and state locks are held so that
7205 	 * we can properly assess the vdev state before we commit to
7206 	 * the initializing operation.
7207 	 */
7208 	mutex_enter(&spa_namespace_lock);
7209 
7210 	for (nvpair_t *pair = nvlist_next_nvpair(nv, NULL);
7211 	    pair != NULL; pair = nvlist_next_nvpair(nv, pair)) {
7212 		uint64_t vdev_guid = fnvpair_value_uint64(pair);
7213 
7214 		int error = spa_vdev_initialize_impl(spa, vdev_guid, cmd_type,
7215 		    &vd_list);
7216 		if (error != 0) {
7217 			char guid_as_str[MAXNAMELEN];
7218 
7219 			(void) snprintf(guid_as_str, sizeof (guid_as_str),
7220 			    "%llu", (unsigned long long)vdev_guid);
7221 			fnvlist_add_int64(vdev_errlist, guid_as_str, error);
7222 			total_errors++;
7223 		}
7224 	}
7225 
7226 	/* Wait for all initialize threads to stop. */
7227 	vdev_initialize_stop_wait(spa, &vd_list);
7228 
7229 	/* Sync out the initializing state */
7230 	txg_wait_synced(spa->spa_dsl_pool, 0);
7231 	mutex_exit(&spa_namespace_lock);
7232 
7233 	list_destroy(&vd_list);
7234 
7235 	return (total_errors);
7236 }
7237 
7238 static int
7239 spa_vdev_trim_impl(spa_t *spa, uint64_t guid, uint64_t cmd_type,
7240     uint64_t rate, boolean_t partial, boolean_t secure, list_t *vd_list)
7241 {
7242 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
7243 
7244 	spa_config_enter(spa, SCL_CONFIG | SCL_STATE, FTAG, RW_READER);
7245 
7246 	/* Look up vdev and ensure it's a leaf. */
7247 	vdev_t *vd = spa_lookup_by_guid(spa, guid, B_FALSE);
7248 	if (vd == NULL || vd->vdev_detached) {
7249 		spa_config_exit(spa, SCL_CONFIG | SCL_STATE, FTAG);
7250 		return (SET_ERROR(ENODEV));
7251 	} else if (!vd->vdev_ops->vdev_op_leaf || !vdev_is_concrete(vd)) {
7252 		spa_config_exit(spa, SCL_CONFIG | SCL_STATE, FTAG);
7253 		return (SET_ERROR(EINVAL));
7254 	} else if (!vdev_writeable(vd)) {
7255 		spa_config_exit(spa, SCL_CONFIG | SCL_STATE, FTAG);
7256 		return (SET_ERROR(EROFS));
7257 	} else if (!vd->vdev_has_trim) {
7258 		spa_config_exit(spa, SCL_CONFIG | SCL_STATE, FTAG);
7259 		return (SET_ERROR(EOPNOTSUPP));
7260 	} else if (secure && !vd->vdev_has_securetrim) {
7261 		spa_config_exit(spa, SCL_CONFIG | SCL_STATE, FTAG);
7262 		return (SET_ERROR(EOPNOTSUPP));
7263 	}
7264 	mutex_enter(&vd->vdev_trim_lock);
7265 	spa_config_exit(spa, SCL_CONFIG | SCL_STATE, FTAG);
7266 
7267 	/*
7268 	 * When we activate a TRIM action we check to see if the
7269 	 * vdev_trim_thread is NULL. We do this instead of using the
7270 	 * vdev_trim_state since there might be a previous TRIM process
7271 	 * which has completed but the thread is not exited.
7272 	 */
7273 	if (cmd_type == POOL_TRIM_START &&
7274 	    (vd->vdev_trim_thread != NULL || vd->vdev_top->vdev_removing)) {
7275 		mutex_exit(&vd->vdev_trim_lock);
7276 		return (SET_ERROR(EBUSY));
7277 	} else if (cmd_type == POOL_TRIM_CANCEL &&
7278 	    (vd->vdev_trim_state != VDEV_TRIM_ACTIVE &&
7279 	    vd->vdev_trim_state != VDEV_TRIM_SUSPENDED)) {
7280 		mutex_exit(&vd->vdev_trim_lock);
7281 		return (SET_ERROR(ESRCH));
7282 	} else if (cmd_type == POOL_TRIM_SUSPEND &&
7283 	    vd->vdev_trim_state != VDEV_TRIM_ACTIVE) {
7284 		mutex_exit(&vd->vdev_trim_lock);
7285 		return (SET_ERROR(ESRCH));
7286 	}
7287 
7288 	switch (cmd_type) {
7289 	case POOL_TRIM_START:
7290 		vdev_trim(vd, rate, partial, secure);
7291 		break;
7292 	case POOL_TRIM_CANCEL:
7293 		vdev_trim_stop(vd, VDEV_TRIM_CANCELED, vd_list);
7294 		break;
7295 	case POOL_TRIM_SUSPEND:
7296 		vdev_trim_stop(vd, VDEV_TRIM_SUSPENDED, vd_list);
7297 		break;
7298 	default:
7299 		panic("invalid cmd_type %llu", (unsigned long long)cmd_type);
7300 	}
7301 	mutex_exit(&vd->vdev_trim_lock);
7302 
7303 	return (0);
7304 }
7305 
7306 /*
7307  * Initiates a manual TRIM for the requested vdevs. This kicks off individual
7308  * TRIM threads for each child vdev.  These threads pass over all of the free
7309  * space in the vdev's metaslabs and issues TRIM commands for that space.
7310  */
7311 int
7312 spa_vdev_trim(spa_t *spa, nvlist_t *nv, uint64_t cmd_type, uint64_t rate,
7313     boolean_t partial, boolean_t secure, nvlist_t *vdev_errlist)
7314 {
7315 	int total_errors = 0;
7316 	list_t vd_list;
7317 
7318 	list_create(&vd_list, sizeof (vdev_t),
7319 	    offsetof(vdev_t, vdev_trim_node));
7320 
7321 	/*
7322 	 * We hold the namespace lock through the whole function
7323 	 * to prevent any changes to the pool while we're starting or
7324 	 * stopping TRIM. The config and state locks are held so that
7325 	 * we can properly assess the vdev state before we commit to
7326 	 * the TRIM operation.
7327 	 */
7328 	mutex_enter(&spa_namespace_lock);
7329 
7330 	for (nvpair_t *pair = nvlist_next_nvpair(nv, NULL);
7331 	    pair != NULL; pair = nvlist_next_nvpair(nv, pair)) {
7332 		uint64_t vdev_guid = fnvpair_value_uint64(pair);
7333 
7334 		int error = spa_vdev_trim_impl(spa, vdev_guid, cmd_type,
7335 		    rate, partial, secure, &vd_list);
7336 		if (error != 0) {
7337 			char guid_as_str[MAXNAMELEN];
7338 
7339 			(void) snprintf(guid_as_str, sizeof (guid_as_str),
7340 			    "%llu", (unsigned long long)vdev_guid);
7341 			fnvlist_add_int64(vdev_errlist, guid_as_str, error);
7342 			total_errors++;
7343 		}
7344 	}
7345 
7346 	/* Wait for all TRIM threads to stop. */
7347 	vdev_trim_stop_wait(spa, &vd_list);
7348 
7349 	/* Sync out the TRIM state */
7350 	txg_wait_synced(spa->spa_dsl_pool, 0);
7351 	mutex_exit(&spa_namespace_lock);
7352 
7353 	list_destroy(&vd_list);
7354 
7355 	return (total_errors);
7356 }
7357 
7358 /*
7359  * Split a set of devices from their mirrors, and create a new pool from them.
7360  */
7361 int
7362 spa_vdev_split_mirror(spa_t *spa, char *newname, nvlist_t *config,
7363     nvlist_t *props, boolean_t exp)
7364 {
7365 	int error = 0;
7366 	uint64_t txg, *glist;
7367 	spa_t *newspa;
7368 	uint_t c, children, lastlog;
7369 	nvlist_t **child, *nvl, *tmp;
7370 	dmu_tx_t *tx;
7371 	char *altroot = NULL;
7372 	vdev_t *rvd, **vml = NULL;			/* vdev modify list */
7373 	boolean_t activate_slog;
7374 
7375 	ASSERT(spa_writeable(spa));
7376 
7377 	txg = spa_vdev_enter(spa);
7378 
7379 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
7380 	if (spa_feature_is_active(spa, SPA_FEATURE_POOL_CHECKPOINT)) {
7381 		error = (spa_has_checkpoint(spa)) ?
7382 		    ZFS_ERR_CHECKPOINT_EXISTS : ZFS_ERR_DISCARDING_CHECKPOINT;
7383 		return (spa_vdev_exit(spa, NULL, txg, error));
7384 	}
7385 
7386 	/* clear the log and flush everything up to now */
7387 	activate_slog = spa_passivate_log(spa);
7388 	(void) spa_vdev_config_exit(spa, NULL, txg, 0, FTAG);
7389 	error = spa_reset_logs(spa);
7390 	txg = spa_vdev_config_enter(spa);
7391 
7392 	if (activate_slog)
7393 		spa_activate_log(spa);
7394 
7395 	if (error != 0)
7396 		return (spa_vdev_exit(spa, NULL, txg, error));
7397 
7398 	/* check new spa name before going any further */
7399 	if (spa_lookup(newname) != NULL)
7400 		return (spa_vdev_exit(spa, NULL, txg, EEXIST));
7401 
7402 	/*
7403 	 * scan through all the children to ensure they're all mirrors
7404 	 */
7405 	if (nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE, &nvl) != 0 ||
7406 	    nvlist_lookup_nvlist_array(nvl, ZPOOL_CONFIG_CHILDREN, &child,
7407 	    &children) != 0)
7408 		return (spa_vdev_exit(spa, NULL, txg, EINVAL));
7409 
7410 	/* first, check to ensure we've got the right child count */
7411 	rvd = spa->spa_root_vdev;
7412 	lastlog = 0;
7413 	for (c = 0; c < rvd->vdev_children; c++) {
7414 		vdev_t *vd = rvd->vdev_child[c];
7415 
7416 		/* don't count the holes & logs as children */
7417 		if (vd->vdev_islog || (vd->vdev_ops != &vdev_indirect_ops &&
7418 		    !vdev_is_concrete(vd))) {
7419 			if (lastlog == 0)
7420 				lastlog = c;
7421 			continue;
7422 		}
7423 
7424 		lastlog = 0;
7425 	}
7426 	if (children != (lastlog != 0 ? lastlog : rvd->vdev_children))
7427 		return (spa_vdev_exit(spa, NULL, txg, EINVAL));
7428 
7429 	/* next, ensure no spare or cache devices are part of the split */
7430 	if (nvlist_lookup_nvlist(nvl, ZPOOL_CONFIG_SPARES, &tmp) == 0 ||
7431 	    nvlist_lookup_nvlist(nvl, ZPOOL_CONFIG_L2CACHE, &tmp) == 0)
7432 		return (spa_vdev_exit(spa, NULL, txg, EINVAL));
7433 
7434 	vml = kmem_zalloc(children * sizeof (vdev_t *), KM_SLEEP);
7435 	glist = kmem_zalloc(children * sizeof (uint64_t), KM_SLEEP);
7436 
7437 	/* then, loop over each vdev and validate it */
7438 	for (c = 0; c < children; c++) {
7439 		uint64_t is_hole = 0;
7440 
7441 		(void) nvlist_lookup_uint64(child[c], ZPOOL_CONFIG_IS_HOLE,
7442 		    &is_hole);
7443 
7444 		if (is_hole != 0) {
7445 			if (spa->spa_root_vdev->vdev_child[c]->vdev_ishole ||
7446 			    spa->spa_root_vdev->vdev_child[c]->vdev_islog) {
7447 				continue;
7448 			} else {
7449 				error = SET_ERROR(EINVAL);
7450 				break;
7451 			}
7452 		}
7453 
7454 		/* deal with indirect vdevs */
7455 		if (spa->spa_root_vdev->vdev_child[c]->vdev_ops ==
7456 		    &vdev_indirect_ops)
7457 			continue;
7458 
7459 		/* which disk is going to be split? */
7460 		if (nvlist_lookup_uint64(child[c], ZPOOL_CONFIG_GUID,
7461 		    &glist[c]) != 0) {
7462 			error = SET_ERROR(EINVAL);
7463 			break;
7464 		}
7465 
7466 		/* look it up in the spa */
7467 		vml[c] = spa_lookup_by_guid(spa, glist[c], B_FALSE);
7468 		if (vml[c] == NULL) {
7469 			error = SET_ERROR(ENODEV);
7470 			break;
7471 		}
7472 
7473 		/* make sure there's nothing stopping the split */
7474 		if (vml[c]->vdev_parent->vdev_ops != &vdev_mirror_ops ||
7475 		    vml[c]->vdev_islog ||
7476 		    !vdev_is_concrete(vml[c]) ||
7477 		    vml[c]->vdev_isspare ||
7478 		    vml[c]->vdev_isl2cache ||
7479 		    !vdev_writeable(vml[c]) ||
7480 		    vml[c]->vdev_children != 0 ||
7481 		    vml[c]->vdev_state != VDEV_STATE_HEALTHY ||
7482 		    c != spa->spa_root_vdev->vdev_child[c]->vdev_id) {
7483 			error = SET_ERROR(EINVAL);
7484 			break;
7485 		}
7486 
7487 		if (vdev_dtl_required(vml[c]) ||
7488 		    vdev_resilver_needed(vml[c], NULL, NULL)) {
7489 			error = SET_ERROR(EBUSY);
7490 			break;
7491 		}
7492 
7493 		/* we need certain info from the top level */
7494 		VERIFY(nvlist_add_uint64(child[c], ZPOOL_CONFIG_METASLAB_ARRAY,
7495 		    vml[c]->vdev_top->vdev_ms_array) == 0);
7496 		VERIFY(nvlist_add_uint64(child[c], ZPOOL_CONFIG_METASLAB_SHIFT,
7497 		    vml[c]->vdev_top->vdev_ms_shift) == 0);
7498 		VERIFY(nvlist_add_uint64(child[c], ZPOOL_CONFIG_ASIZE,
7499 		    vml[c]->vdev_top->vdev_asize) == 0);
7500 		VERIFY(nvlist_add_uint64(child[c], ZPOOL_CONFIG_ASHIFT,
7501 		    vml[c]->vdev_top->vdev_ashift) == 0);
7502 
7503 		/* transfer per-vdev ZAPs */
7504 		ASSERT3U(vml[c]->vdev_leaf_zap, !=, 0);
7505 		VERIFY0(nvlist_add_uint64(child[c],
7506 		    ZPOOL_CONFIG_VDEV_LEAF_ZAP, vml[c]->vdev_leaf_zap));
7507 
7508 		ASSERT3U(vml[c]->vdev_top->vdev_top_zap, !=, 0);
7509 		VERIFY0(nvlist_add_uint64(child[c],
7510 		    ZPOOL_CONFIG_VDEV_TOP_ZAP,
7511 		    vml[c]->vdev_parent->vdev_top_zap));
7512 	}
7513 
7514 	if (error != 0) {
7515 		kmem_free(vml, children * sizeof (vdev_t *));
7516 		kmem_free(glist, children * sizeof (uint64_t));
7517 		return (spa_vdev_exit(spa, NULL, txg, error));
7518 	}
7519 
7520 	/* stop writers from using the disks */
7521 	for (c = 0; c < children; c++) {
7522 		if (vml[c] != NULL)
7523 			vml[c]->vdev_offline = B_TRUE;
7524 	}
7525 	vdev_reopen(spa->spa_root_vdev);
7526 
7527 	/*
7528 	 * Temporarily record the splitting vdevs in the spa config.  This
7529 	 * will disappear once the config is regenerated.
7530 	 */
7531 	VERIFY(nvlist_alloc(&nvl, NV_UNIQUE_NAME, KM_SLEEP) == 0);
7532 	VERIFY(nvlist_add_uint64_array(nvl, ZPOOL_CONFIG_SPLIT_LIST,
7533 	    glist, children) == 0);
7534 	kmem_free(glist, children * sizeof (uint64_t));
7535 
7536 	mutex_enter(&spa->spa_props_lock);
7537 	VERIFY(nvlist_add_nvlist(spa->spa_config, ZPOOL_CONFIG_SPLIT,
7538 	    nvl) == 0);
7539 	mutex_exit(&spa->spa_props_lock);
7540 	spa->spa_config_splitting = nvl;
7541 	vdev_config_dirty(spa->spa_root_vdev);
7542 
7543 	/* configure and create the new pool */
7544 	VERIFY(nvlist_add_string(config, ZPOOL_CONFIG_POOL_NAME, newname) == 0);
7545 	VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_POOL_STATE,
7546 	    exp ? POOL_STATE_EXPORTED : POOL_STATE_ACTIVE) == 0);
7547 	VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_VERSION,
7548 	    spa_version(spa)) == 0);
7549 	VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_POOL_TXG,
7550 	    spa->spa_config_txg) == 0);
7551 	VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_POOL_GUID,
7552 	    spa_generate_guid(NULL)) == 0);
7553 	VERIFY0(nvlist_add_boolean(config, ZPOOL_CONFIG_HAS_PER_VDEV_ZAPS));
7554 	(void) nvlist_lookup_string(props,
7555 	    zpool_prop_to_name(ZPOOL_PROP_ALTROOT), &altroot);
7556 
7557 	/* add the new pool to the namespace */
7558 	newspa = spa_add(newname, config, altroot);
7559 	newspa->spa_avz_action = AVZ_ACTION_REBUILD;
7560 	newspa->spa_config_txg = spa->spa_config_txg;
7561 	spa_set_log_state(newspa, SPA_LOG_CLEAR);
7562 
7563 	/* release the spa config lock, retaining the namespace lock */
7564 	spa_vdev_config_exit(spa, NULL, txg, 0, FTAG);
7565 
7566 	if (zio_injection_enabled)
7567 		zio_handle_panic_injection(spa, FTAG, 1);
7568 
7569 	spa_activate(newspa, spa_mode_global);
7570 	spa_async_suspend(newspa);
7571 
7572 	/*
7573 	 * Temporarily stop the initializing and TRIM activity.  We set the
7574 	 * state to ACTIVE so that we know to resume initializing or TRIM
7575 	 * once the split has completed.
7576 	 */
7577 	list_t vd_initialize_list;
7578 	list_create(&vd_initialize_list, sizeof (vdev_t),
7579 	    offsetof(vdev_t, vdev_initialize_node));
7580 
7581 	list_t vd_trim_list;
7582 	list_create(&vd_trim_list, sizeof (vdev_t),
7583 	    offsetof(vdev_t, vdev_trim_node));
7584 
7585 	for (c = 0; c < children; c++) {
7586 		if (vml[c] != NULL && vml[c]->vdev_ops != &vdev_indirect_ops) {
7587 			mutex_enter(&vml[c]->vdev_initialize_lock);
7588 			vdev_initialize_stop(vml[c],
7589 			    VDEV_INITIALIZE_ACTIVE, &vd_initialize_list);
7590 			mutex_exit(&vml[c]->vdev_initialize_lock);
7591 
7592 			mutex_enter(&vml[c]->vdev_trim_lock);
7593 			vdev_trim_stop(vml[c], VDEV_TRIM_ACTIVE, &vd_trim_list);
7594 			mutex_exit(&vml[c]->vdev_trim_lock);
7595 		}
7596 	}
7597 
7598 	vdev_initialize_stop_wait(spa, &vd_initialize_list);
7599 	vdev_trim_stop_wait(spa, &vd_trim_list);
7600 
7601 	list_destroy(&vd_initialize_list);
7602 	list_destroy(&vd_trim_list);
7603 
7604 	newspa->spa_config_source = SPA_CONFIG_SRC_SPLIT;
7605 	newspa->spa_is_splitting = B_TRUE;
7606 
7607 	/* create the new pool from the disks of the original pool */
7608 	error = spa_load(newspa, SPA_LOAD_IMPORT, SPA_IMPORT_ASSEMBLE);
7609 	if (error)
7610 		goto out;
7611 
7612 	/* if that worked, generate a real config for the new pool */
7613 	if (newspa->spa_root_vdev != NULL) {
7614 		VERIFY(nvlist_alloc(&newspa->spa_config_splitting,
7615 		    NV_UNIQUE_NAME, KM_SLEEP) == 0);
7616 		VERIFY(nvlist_add_uint64(newspa->spa_config_splitting,
7617 		    ZPOOL_CONFIG_SPLIT_GUID, spa_guid(spa)) == 0);
7618 		spa_config_set(newspa, spa_config_generate(newspa, NULL, -1ULL,
7619 		    B_TRUE));
7620 	}
7621 
7622 	/* set the props */
7623 	if (props != NULL) {
7624 		spa_configfile_set(newspa, props, B_FALSE);
7625 		error = spa_prop_set(newspa, props);
7626 		if (error)
7627 			goto out;
7628 	}
7629 
7630 	/* flush everything */
7631 	txg = spa_vdev_config_enter(newspa);
7632 	vdev_config_dirty(newspa->spa_root_vdev);
7633 	(void) spa_vdev_config_exit(newspa, NULL, txg, 0, FTAG);
7634 
7635 	if (zio_injection_enabled)
7636 		zio_handle_panic_injection(spa, FTAG, 2);
7637 
7638 	spa_async_resume(newspa);
7639 
7640 	/* finally, update the original pool's config */
7641 	txg = spa_vdev_config_enter(spa);
7642 	tx = dmu_tx_create_dd(spa_get_dsl(spa)->dp_mos_dir);
7643 	error = dmu_tx_assign(tx, TXG_WAIT);
7644 	if (error != 0)
7645 		dmu_tx_abort(tx);
7646 	for (c = 0; c < children; c++) {
7647 		if (vml[c] != NULL && vml[c]->vdev_ops != &vdev_indirect_ops) {
7648 			vdev_t *tvd = vml[c]->vdev_top;
7649 
7650 			/*
7651 			 * Need to be sure the detachable VDEV is not
7652 			 * on any *other* txg's DTL list to prevent it
7653 			 * from being accessed after it's freed.
7654 			 */
7655 			for (int t = 0; t < TXG_SIZE; t++) {
7656 				(void) txg_list_remove_this(
7657 				    &tvd->vdev_dtl_list, vml[c], t);
7658 			}
7659 
7660 			vdev_split(vml[c]);
7661 			if (error == 0)
7662 				spa_history_log_internal(spa, "detach", tx,
7663 				    "vdev=%s", vml[c]->vdev_path);
7664 
7665 			vdev_free(vml[c]);
7666 		}
7667 	}
7668 	spa->spa_avz_action = AVZ_ACTION_REBUILD;
7669 	vdev_config_dirty(spa->spa_root_vdev);
7670 	spa->spa_config_splitting = NULL;
7671 	nvlist_free(nvl);
7672 	if (error == 0)
7673 		dmu_tx_commit(tx);
7674 	(void) spa_vdev_exit(spa, NULL, txg, 0);
7675 
7676 	if (zio_injection_enabled)
7677 		zio_handle_panic_injection(spa, FTAG, 3);
7678 
7679 	/* split is complete; log a history record */
7680 	spa_history_log_internal(newspa, "split", NULL,
7681 	    "from pool %s", spa_name(spa));
7682 
7683 	newspa->spa_is_splitting = B_FALSE;
7684 	kmem_free(vml, children * sizeof (vdev_t *));
7685 
7686 	/* if we're not going to mount the filesystems in userland, export */
7687 	if (exp)
7688 		error = spa_export_common(newname, POOL_STATE_EXPORTED, NULL,
7689 		    B_FALSE, B_FALSE);
7690 
7691 	return (error);
7692 
7693 out:
7694 	spa_unload(newspa);
7695 	spa_deactivate(newspa);
7696 	spa_remove(newspa);
7697 
7698 	txg = spa_vdev_config_enter(spa);
7699 
7700 	/* re-online all offlined disks */
7701 	for (c = 0; c < children; c++) {
7702 		if (vml[c] != NULL)
7703 			vml[c]->vdev_offline = B_FALSE;
7704 	}
7705 
7706 	/* restart initializing or trimming disks as necessary */
7707 	spa_async_request(spa, SPA_ASYNC_INITIALIZE_RESTART);
7708 	spa_async_request(spa, SPA_ASYNC_TRIM_RESTART);
7709 	spa_async_request(spa, SPA_ASYNC_AUTOTRIM_RESTART);
7710 
7711 	vdev_reopen(spa->spa_root_vdev);
7712 
7713 	nvlist_free(spa->spa_config_splitting);
7714 	spa->spa_config_splitting = NULL;
7715 	(void) spa_vdev_exit(spa, NULL, txg, error);
7716 
7717 	kmem_free(vml, children * sizeof (vdev_t *));
7718 	return (error);
7719 }
7720 
7721 /*
7722  * Find any device that's done replacing, or a vdev marked 'unspare' that's
7723  * currently spared, so we can detach it.
7724  */
7725 static vdev_t *
7726 spa_vdev_resilver_done_hunt(vdev_t *vd)
7727 {
7728 	vdev_t *newvd, *oldvd;
7729 
7730 	for (int c = 0; c < vd->vdev_children; c++) {
7731 		oldvd = spa_vdev_resilver_done_hunt(vd->vdev_child[c]);
7732 		if (oldvd != NULL)
7733 			return (oldvd);
7734 	}
7735 
7736 	/*
7737 	 * Check for a completed replacement.  We always consider the first
7738 	 * vdev in the list to be the oldest vdev, and the last one to be
7739 	 * the newest (see spa_vdev_attach() for how that works).  In
7740 	 * the case where the newest vdev is faulted, we will not automatically
7741 	 * remove it after a resilver completes.  This is OK as it will require
7742 	 * user intervention to determine which disk the admin wishes to keep.
7743 	 */
7744 	if (vd->vdev_ops == &vdev_replacing_ops) {
7745 		ASSERT(vd->vdev_children > 1);
7746 
7747 		newvd = vd->vdev_child[vd->vdev_children - 1];
7748 		oldvd = vd->vdev_child[0];
7749 
7750 		if (vdev_dtl_empty(newvd, DTL_MISSING) &&
7751 		    vdev_dtl_empty(newvd, DTL_OUTAGE) &&
7752 		    !vdev_dtl_required(oldvd))
7753 			return (oldvd);
7754 	}
7755 
7756 	/*
7757 	 * Check for a completed resilver with the 'unspare' flag set.
7758 	 * Also potentially update faulted state.
7759 	 */
7760 	if (vd->vdev_ops == &vdev_spare_ops) {
7761 		vdev_t *first = vd->vdev_child[0];
7762 		vdev_t *last = vd->vdev_child[vd->vdev_children - 1];
7763 
7764 		if (last->vdev_unspare) {
7765 			oldvd = first;
7766 			newvd = last;
7767 		} else if (first->vdev_unspare) {
7768 			oldvd = last;
7769 			newvd = first;
7770 		} else {
7771 			oldvd = NULL;
7772 		}
7773 
7774 		if (oldvd != NULL &&
7775 		    vdev_dtl_empty(newvd, DTL_MISSING) &&
7776 		    vdev_dtl_empty(newvd, DTL_OUTAGE) &&
7777 		    !vdev_dtl_required(oldvd))
7778 			return (oldvd);
7779 
7780 		vdev_propagate_state(vd);
7781 
7782 		/*
7783 		 * If there are more than two spares attached to a disk,
7784 		 * and those spares are not required, then we want to
7785 		 * attempt to free them up now so that they can be used
7786 		 * by other pools.  Once we're back down to a single
7787 		 * disk+spare, we stop removing them.
7788 		 */
7789 		if (vd->vdev_children > 2) {
7790 			newvd = vd->vdev_child[1];
7791 
7792 			if (newvd->vdev_isspare && last->vdev_isspare &&
7793 			    vdev_dtl_empty(last, DTL_MISSING) &&
7794 			    vdev_dtl_empty(last, DTL_OUTAGE) &&
7795 			    !vdev_dtl_required(newvd))
7796 				return (newvd);
7797 		}
7798 	}
7799 
7800 	return (NULL);
7801 }
7802 
7803 static void
7804 spa_vdev_resilver_done(spa_t *spa)
7805 {
7806 	vdev_t *vd, *pvd, *ppvd;
7807 	uint64_t guid, sguid, pguid, ppguid;
7808 
7809 	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
7810 
7811 	while ((vd = spa_vdev_resilver_done_hunt(spa->spa_root_vdev)) != NULL) {
7812 		pvd = vd->vdev_parent;
7813 		ppvd = pvd->vdev_parent;
7814 		guid = vd->vdev_guid;
7815 		pguid = pvd->vdev_guid;
7816 		ppguid = ppvd->vdev_guid;
7817 		sguid = 0;
7818 		/*
7819 		 * If we have just finished replacing a hot spared device, then
7820 		 * we need to detach the parent's first child (the original hot
7821 		 * spare) as well.
7822 		 */
7823 		if (ppvd->vdev_ops == &vdev_spare_ops && pvd->vdev_id == 0 &&
7824 		    ppvd->vdev_children == 2) {
7825 			ASSERT(pvd->vdev_ops == &vdev_replacing_ops);
7826 			sguid = ppvd->vdev_child[1]->vdev_guid;
7827 		}
7828 		ASSERT(vd->vdev_resilver_txg == 0 || !vdev_dtl_required(vd));
7829 
7830 		spa_config_exit(spa, SCL_ALL, FTAG);
7831 		if (spa_vdev_detach(spa, guid, pguid, B_TRUE) != 0)
7832 			return;
7833 		if (sguid && spa_vdev_detach(spa, sguid, ppguid, B_TRUE) != 0)
7834 			return;
7835 		spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
7836 	}
7837 
7838 	spa_config_exit(spa, SCL_ALL, FTAG);
7839 
7840 	/*
7841 	 * If a detach was not performed above replace waiters will not have
7842 	 * been notified.  In which case we must do so now.
7843 	 */
7844 	spa_notify_waiters(spa);
7845 }
7846 
7847 /*
7848  * Update the stored path or FRU for this vdev.
7849  */
7850 static int
7851 spa_vdev_set_common(spa_t *spa, uint64_t guid, const char *value,
7852     boolean_t ispath)
7853 {
7854 	vdev_t *vd;
7855 	boolean_t sync = B_FALSE;
7856 
7857 	ASSERT(spa_writeable(spa));
7858 
7859 	spa_vdev_state_enter(spa, SCL_ALL);
7860 
7861 	if ((vd = spa_lookup_by_guid(spa, guid, B_TRUE)) == NULL)
7862 		return (spa_vdev_state_exit(spa, NULL, ENOENT));
7863 
7864 	if (!vd->vdev_ops->vdev_op_leaf)
7865 		return (spa_vdev_state_exit(spa, NULL, ENOTSUP));
7866 
7867 	if (ispath) {
7868 		if (strcmp(value, vd->vdev_path) != 0) {
7869 			spa_strfree(vd->vdev_path);
7870 			vd->vdev_path = spa_strdup(value);
7871 			sync = B_TRUE;
7872 		}
7873 	} else {
7874 		if (vd->vdev_fru == NULL) {
7875 			vd->vdev_fru = spa_strdup(value);
7876 			sync = B_TRUE;
7877 		} else if (strcmp(value, vd->vdev_fru) != 0) {
7878 			spa_strfree(vd->vdev_fru);
7879 			vd->vdev_fru = spa_strdup(value);
7880 			sync = B_TRUE;
7881 		}
7882 	}
7883 
7884 	return (spa_vdev_state_exit(spa, sync ? vd : NULL, 0));
7885 }
7886 
7887 int
7888 spa_vdev_setpath(spa_t *spa, uint64_t guid, const char *newpath)
7889 {
7890 	return (spa_vdev_set_common(spa, guid, newpath, B_TRUE));
7891 }
7892 
7893 int
7894 spa_vdev_setfru(spa_t *spa, uint64_t guid, const char *newfru)
7895 {
7896 	return (spa_vdev_set_common(spa, guid, newfru, B_FALSE));
7897 }
7898 
7899 /*
7900  * ==========================================================================
7901  * SPA Scanning
7902  * ==========================================================================
7903  */
7904 int
7905 spa_scrub_pause_resume(spa_t *spa, pool_scrub_cmd_t cmd)
7906 {
7907 	ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == 0);
7908 
7909 	if (dsl_scan_resilvering(spa->spa_dsl_pool))
7910 		return (SET_ERROR(EBUSY));
7911 
7912 	return (dsl_scrub_set_pause_resume(spa->spa_dsl_pool, cmd));
7913 }
7914 
7915 int
7916 spa_scan_stop(spa_t *spa)
7917 {
7918 	ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == 0);
7919 	if (dsl_scan_resilvering(spa->spa_dsl_pool))
7920 		return (SET_ERROR(EBUSY));
7921 	return (dsl_scan_cancel(spa->spa_dsl_pool));
7922 }
7923 
7924 int
7925 spa_scan(spa_t *spa, pool_scan_func_t func)
7926 {
7927 	ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == 0);
7928 
7929 	if (func >= POOL_SCAN_FUNCS || func == POOL_SCAN_NONE)
7930 		return (SET_ERROR(ENOTSUP));
7931 
7932 	if (func == POOL_SCAN_RESILVER &&
7933 	    !spa_feature_is_enabled(spa, SPA_FEATURE_RESILVER_DEFER))
7934 		return (SET_ERROR(ENOTSUP));
7935 
7936 	/*
7937 	 * If a resilver was requested, but there is no DTL on a
7938 	 * writeable leaf device, we have nothing to do.
7939 	 */
7940 	if (func == POOL_SCAN_RESILVER &&
7941 	    !vdev_resilver_needed(spa->spa_root_vdev, NULL, NULL)) {
7942 		spa_async_request(spa, SPA_ASYNC_RESILVER_DONE);
7943 		return (0);
7944 	}
7945 
7946 	return (dsl_scan(spa->spa_dsl_pool, func));
7947 }
7948 
7949 /*
7950  * ==========================================================================
7951  * SPA async task processing
7952  * ==========================================================================
7953  */
7954 
7955 static void
7956 spa_async_remove(spa_t *spa, vdev_t *vd)
7957 {
7958 	if (vd->vdev_remove_wanted) {
7959 		vd->vdev_remove_wanted = B_FALSE;
7960 		vd->vdev_delayed_close = B_FALSE;
7961 		vdev_set_state(vd, B_FALSE, VDEV_STATE_REMOVED, VDEV_AUX_NONE);
7962 
7963 		/*
7964 		 * We want to clear the stats, but we don't want to do a full
7965 		 * vdev_clear() as that will cause us to throw away
7966 		 * degraded/faulted state as well as attempt to reopen the
7967 		 * device, all of which is a waste.
7968 		 */
7969 		vd->vdev_stat.vs_read_errors = 0;
7970 		vd->vdev_stat.vs_write_errors = 0;
7971 		vd->vdev_stat.vs_checksum_errors = 0;
7972 
7973 		vdev_state_dirty(vd->vdev_top);
7974 
7975 		/* Tell userspace that the vdev is gone. */
7976 		zfs_post_remove(spa, vd);
7977 	}
7978 
7979 	for (int c = 0; c < vd->vdev_children; c++)
7980 		spa_async_remove(spa, vd->vdev_child[c]);
7981 }
7982 
7983 static void
7984 spa_async_probe(spa_t *spa, vdev_t *vd)
7985 {
7986 	if (vd->vdev_probe_wanted) {
7987 		vd->vdev_probe_wanted = B_FALSE;
7988 		vdev_reopen(vd);	/* vdev_open() does the actual probe */
7989 	}
7990 
7991 	for (int c = 0; c < vd->vdev_children; c++)
7992 		spa_async_probe(spa, vd->vdev_child[c]);
7993 }
7994 
7995 static void
7996 spa_async_autoexpand(spa_t *spa, vdev_t *vd)
7997 {
7998 	if (!spa->spa_autoexpand)
7999 		return;
8000 
8001 	for (int c = 0; c < vd->vdev_children; c++) {
8002 		vdev_t *cvd = vd->vdev_child[c];
8003 		spa_async_autoexpand(spa, cvd);
8004 	}
8005 
8006 	if (!vd->vdev_ops->vdev_op_leaf || vd->vdev_physpath == NULL)
8007 		return;
8008 
8009 	spa_event_notify(vd->vdev_spa, vd, NULL, ESC_ZFS_VDEV_AUTOEXPAND);
8010 }
8011 
8012 static void
8013 spa_async_thread(void *arg)
8014 {
8015 	spa_t *spa = (spa_t *)arg;
8016 	dsl_pool_t *dp = spa->spa_dsl_pool;
8017 	int tasks;
8018 
8019 	ASSERT(spa->spa_sync_on);
8020 
8021 	mutex_enter(&spa->spa_async_lock);
8022 	tasks = spa->spa_async_tasks;
8023 	spa->spa_async_tasks = 0;
8024 	mutex_exit(&spa->spa_async_lock);
8025 
8026 	/*
8027 	 * See if the config needs to be updated.
8028 	 */
8029 	if (tasks & SPA_ASYNC_CONFIG_UPDATE) {
8030 		uint64_t old_space, new_space;
8031 
8032 		mutex_enter(&spa_namespace_lock);
8033 		old_space = metaslab_class_get_space(spa_normal_class(spa));
8034 		old_space += metaslab_class_get_space(spa_special_class(spa));
8035 		old_space += metaslab_class_get_space(spa_dedup_class(spa));
8036 
8037 		spa_config_update(spa, SPA_CONFIG_UPDATE_POOL);
8038 
8039 		new_space = metaslab_class_get_space(spa_normal_class(spa));
8040 		new_space += metaslab_class_get_space(spa_special_class(spa));
8041 		new_space += metaslab_class_get_space(spa_dedup_class(spa));
8042 		mutex_exit(&spa_namespace_lock);
8043 
8044 		/*
8045 		 * If the pool grew as a result of the config update,
8046 		 * then log an internal history event.
8047 		 */
8048 		if (new_space != old_space) {
8049 			spa_history_log_internal(spa, "vdev online", NULL,
8050 			    "pool '%s' size: %llu(+%llu)",
8051 			    spa_name(spa), (u_longlong_t)new_space,
8052 			    (u_longlong_t)(new_space - old_space));
8053 		}
8054 	}
8055 
8056 	/*
8057 	 * See if any devices need to be marked REMOVED.
8058 	 */
8059 	if (tasks & SPA_ASYNC_REMOVE) {
8060 		spa_vdev_state_enter(spa, SCL_NONE);
8061 		spa_async_remove(spa, spa->spa_root_vdev);
8062 		for (int i = 0; i < spa->spa_l2cache.sav_count; i++)
8063 			spa_async_remove(spa, spa->spa_l2cache.sav_vdevs[i]);
8064 		for (int i = 0; i < spa->spa_spares.sav_count; i++)
8065 			spa_async_remove(spa, spa->spa_spares.sav_vdevs[i]);
8066 		(void) spa_vdev_state_exit(spa, NULL, 0);
8067 	}
8068 
8069 	if ((tasks & SPA_ASYNC_AUTOEXPAND) && !spa_suspended(spa)) {
8070 		spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER);
8071 		spa_async_autoexpand(spa, spa->spa_root_vdev);
8072 		spa_config_exit(spa, SCL_CONFIG, FTAG);
8073 	}
8074 
8075 	/*
8076 	 * See if any devices need to be probed.
8077 	 */
8078 	if (tasks & SPA_ASYNC_PROBE) {
8079 		spa_vdev_state_enter(spa, SCL_NONE);
8080 		spa_async_probe(spa, spa->spa_root_vdev);
8081 		(void) spa_vdev_state_exit(spa, NULL, 0);
8082 	}
8083 
8084 	/*
8085 	 * If any devices are done replacing, detach them.
8086 	 */
8087 	if (tasks & SPA_ASYNC_RESILVER_DONE ||
8088 	    tasks & SPA_ASYNC_REBUILD_DONE) {
8089 		spa_vdev_resilver_done(spa);
8090 	}
8091 
8092 	/*
8093 	 * Kick off a resilver.
8094 	 */
8095 	if (tasks & SPA_ASYNC_RESILVER &&
8096 	    !vdev_rebuild_active(spa->spa_root_vdev) &&
8097 	    (!dsl_scan_resilvering(dp) ||
8098 	    !spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_RESILVER_DEFER)))
8099 		dsl_scan_restart_resilver(dp, 0);
8100 
8101 	if (tasks & SPA_ASYNC_INITIALIZE_RESTART) {
8102 		mutex_enter(&spa_namespace_lock);
8103 		spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER);
8104 		vdev_initialize_restart(spa->spa_root_vdev);
8105 		spa_config_exit(spa, SCL_CONFIG, FTAG);
8106 		mutex_exit(&spa_namespace_lock);
8107 	}
8108 
8109 	if (tasks & SPA_ASYNC_TRIM_RESTART) {
8110 		mutex_enter(&spa_namespace_lock);
8111 		spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER);
8112 		vdev_trim_restart(spa->spa_root_vdev);
8113 		spa_config_exit(spa, SCL_CONFIG, FTAG);
8114 		mutex_exit(&spa_namespace_lock);
8115 	}
8116 
8117 	if (tasks & SPA_ASYNC_AUTOTRIM_RESTART) {
8118 		mutex_enter(&spa_namespace_lock);
8119 		spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER);
8120 		vdev_autotrim_restart(spa);
8121 		spa_config_exit(spa, SCL_CONFIG, FTAG);
8122 		mutex_exit(&spa_namespace_lock);
8123 	}
8124 
8125 	/*
8126 	 * Kick off L2 cache whole device TRIM.
8127 	 */
8128 	if (tasks & SPA_ASYNC_L2CACHE_TRIM) {
8129 		mutex_enter(&spa_namespace_lock);
8130 		spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER);
8131 		vdev_trim_l2arc(spa);
8132 		spa_config_exit(spa, SCL_CONFIG, FTAG);
8133 		mutex_exit(&spa_namespace_lock);
8134 	}
8135 
8136 	/*
8137 	 * Kick off L2 cache rebuilding.
8138 	 */
8139 	if (tasks & SPA_ASYNC_L2CACHE_REBUILD) {
8140 		mutex_enter(&spa_namespace_lock);
8141 		spa_config_enter(spa, SCL_L2ARC, FTAG, RW_READER);
8142 		l2arc_spa_rebuild_start(spa);
8143 		spa_config_exit(spa, SCL_L2ARC, FTAG);
8144 		mutex_exit(&spa_namespace_lock);
8145 	}
8146 
8147 	/*
8148 	 * Let the world know that we're done.
8149 	 */
8150 	mutex_enter(&spa->spa_async_lock);
8151 	spa->spa_async_thread = NULL;
8152 	cv_broadcast(&spa->spa_async_cv);
8153 	mutex_exit(&spa->spa_async_lock);
8154 	thread_exit();
8155 }
8156 
8157 void
8158 spa_async_suspend(spa_t *spa)
8159 {
8160 	mutex_enter(&spa->spa_async_lock);
8161 	spa->spa_async_suspended++;
8162 	while (spa->spa_async_thread != NULL)
8163 		cv_wait(&spa->spa_async_cv, &spa->spa_async_lock);
8164 	mutex_exit(&spa->spa_async_lock);
8165 
8166 	spa_vdev_remove_suspend(spa);
8167 
8168 	zthr_t *condense_thread = spa->spa_condense_zthr;
8169 	if (condense_thread != NULL)
8170 		zthr_cancel(condense_thread);
8171 
8172 	zthr_t *discard_thread = spa->spa_checkpoint_discard_zthr;
8173 	if (discard_thread != NULL)
8174 		zthr_cancel(discard_thread);
8175 
8176 	zthr_t *ll_delete_thread = spa->spa_livelist_delete_zthr;
8177 	if (ll_delete_thread != NULL)
8178 		zthr_cancel(ll_delete_thread);
8179 
8180 	zthr_t *ll_condense_thread = spa->spa_livelist_condense_zthr;
8181 	if (ll_condense_thread != NULL)
8182 		zthr_cancel(ll_condense_thread);
8183 }
8184 
8185 void
8186 spa_async_resume(spa_t *spa)
8187 {
8188 	mutex_enter(&spa->spa_async_lock);
8189 	ASSERT(spa->spa_async_suspended != 0);
8190 	spa->spa_async_suspended--;
8191 	mutex_exit(&spa->spa_async_lock);
8192 	spa_restart_removal(spa);
8193 
8194 	zthr_t *condense_thread = spa->spa_condense_zthr;
8195 	if (condense_thread != NULL)
8196 		zthr_resume(condense_thread);
8197 
8198 	zthr_t *discard_thread = spa->spa_checkpoint_discard_zthr;
8199 	if (discard_thread != NULL)
8200 		zthr_resume(discard_thread);
8201 
8202 	zthr_t *ll_delete_thread = spa->spa_livelist_delete_zthr;
8203 	if (ll_delete_thread != NULL)
8204 		zthr_resume(ll_delete_thread);
8205 
8206 	zthr_t *ll_condense_thread = spa->spa_livelist_condense_zthr;
8207 	if (ll_condense_thread != NULL)
8208 		zthr_resume(ll_condense_thread);
8209 }
8210 
8211 static boolean_t
8212 spa_async_tasks_pending(spa_t *spa)
8213 {
8214 	uint_t non_config_tasks;
8215 	uint_t config_task;
8216 	boolean_t config_task_suspended;
8217 
8218 	non_config_tasks = spa->spa_async_tasks & ~SPA_ASYNC_CONFIG_UPDATE;
8219 	config_task = spa->spa_async_tasks & SPA_ASYNC_CONFIG_UPDATE;
8220 	if (spa->spa_ccw_fail_time == 0) {
8221 		config_task_suspended = B_FALSE;
8222 	} else {
8223 		config_task_suspended =
8224 		    (gethrtime() - spa->spa_ccw_fail_time) <
8225 		    ((hrtime_t)zfs_ccw_retry_interval * NANOSEC);
8226 	}
8227 
8228 	return (non_config_tasks || (config_task && !config_task_suspended));
8229 }
8230 
8231 static void
8232 spa_async_dispatch(spa_t *spa)
8233 {
8234 	mutex_enter(&spa->spa_async_lock);
8235 	if (spa_async_tasks_pending(spa) &&
8236 	    !spa->spa_async_suspended &&
8237 	    spa->spa_async_thread == NULL)
8238 		spa->spa_async_thread = thread_create(NULL, 0,
8239 		    spa_async_thread, spa, 0, &p0, TS_RUN, maxclsyspri);
8240 	mutex_exit(&spa->spa_async_lock);
8241 }
8242 
8243 void
8244 spa_async_request(spa_t *spa, int task)
8245 {
8246 	zfs_dbgmsg("spa=%s async request task=%u", spa->spa_name, task);
8247 	mutex_enter(&spa->spa_async_lock);
8248 	spa->spa_async_tasks |= task;
8249 	mutex_exit(&spa->spa_async_lock);
8250 }
8251 
8252 int
8253 spa_async_tasks(spa_t *spa)
8254 {
8255 	return (spa->spa_async_tasks);
8256 }
8257 
8258 /*
8259  * ==========================================================================
8260  * SPA syncing routines
8261  * ==========================================================================
8262  */
8263 
8264 
8265 static int
8266 bpobj_enqueue_cb(void *arg, const blkptr_t *bp, boolean_t bp_freed,
8267     dmu_tx_t *tx)
8268 {
8269 	bpobj_t *bpo = arg;
8270 	bpobj_enqueue(bpo, bp, bp_freed, tx);
8271 	return (0);
8272 }
8273 
8274 int
8275 bpobj_enqueue_alloc_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
8276 {
8277 	return (bpobj_enqueue_cb(arg, bp, B_FALSE, tx));
8278 }
8279 
8280 int
8281 bpobj_enqueue_free_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
8282 {
8283 	return (bpobj_enqueue_cb(arg, bp, B_TRUE, tx));
8284 }
8285 
8286 static int
8287 spa_free_sync_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
8288 {
8289 	zio_t *pio = arg;
8290 
8291 	zio_nowait(zio_free_sync(pio, pio->io_spa, dmu_tx_get_txg(tx), bp,
8292 	    pio->io_flags));
8293 	return (0);
8294 }
8295 
8296 static int
8297 bpobj_spa_free_sync_cb(void *arg, const blkptr_t *bp, boolean_t bp_freed,
8298     dmu_tx_t *tx)
8299 {
8300 	ASSERT(!bp_freed);
8301 	return (spa_free_sync_cb(arg, bp, tx));
8302 }
8303 
8304 /*
8305  * Note: this simple function is not inlined to make it easier to dtrace the
8306  * amount of time spent syncing frees.
8307  */
8308 static void
8309 spa_sync_frees(spa_t *spa, bplist_t *bpl, dmu_tx_t *tx)
8310 {
8311 	zio_t *zio = zio_root(spa, NULL, NULL, 0);
8312 	bplist_iterate(bpl, spa_free_sync_cb, zio, tx);
8313 	VERIFY(zio_wait(zio) == 0);
8314 }
8315 
8316 /*
8317  * Note: this simple function is not inlined to make it easier to dtrace the
8318  * amount of time spent syncing deferred frees.
8319  */
8320 static void
8321 spa_sync_deferred_frees(spa_t *spa, dmu_tx_t *tx)
8322 {
8323 	if (spa_sync_pass(spa) != 1)
8324 		return;
8325 
8326 	/*
8327 	 * Note:
8328 	 * If the log space map feature is active, we stop deferring
8329 	 * frees to the next TXG and therefore running this function
8330 	 * would be considered a no-op as spa_deferred_bpobj should
8331 	 * not have any entries.
8332 	 *
8333 	 * That said we run this function anyway (instead of returning
8334 	 * immediately) for the edge-case scenario where we just
8335 	 * activated the log space map feature in this TXG but we have
8336 	 * deferred frees from the previous TXG.
8337 	 */
8338 	zio_t *zio = zio_root(spa, NULL, NULL, 0);
8339 	VERIFY3U(bpobj_iterate(&spa->spa_deferred_bpobj,
8340 	    bpobj_spa_free_sync_cb, zio, tx), ==, 0);
8341 	VERIFY0(zio_wait(zio));
8342 }
8343 
8344 static void
8345 spa_sync_nvlist(spa_t *spa, uint64_t obj, nvlist_t *nv, dmu_tx_t *tx)
8346 {
8347 	char *packed = NULL;
8348 	size_t bufsize;
8349 	size_t nvsize = 0;
8350 	dmu_buf_t *db;
8351 
8352 	VERIFY(nvlist_size(nv, &nvsize, NV_ENCODE_XDR) == 0);
8353 
8354 	/*
8355 	 * Write full (SPA_CONFIG_BLOCKSIZE) blocks of configuration
8356 	 * information.  This avoids the dmu_buf_will_dirty() path and
8357 	 * saves us a pre-read to get data we don't actually care about.
8358 	 */
8359 	bufsize = P2ROUNDUP((uint64_t)nvsize, SPA_CONFIG_BLOCKSIZE);
8360 	packed = vmem_alloc(bufsize, KM_SLEEP);
8361 
8362 	VERIFY(nvlist_pack(nv, &packed, &nvsize, NV_ENCODE_XDR,
8363 	    KM_SLEEP) == 0);
8364 	bzero(packed + nvsize, bufsize - nvsize);
8365 
8366 	dmu_write(spa->spa_meta_objset, obj, 0, bufsize, packed, tx);
8367 
8368 	vmem_free(packed, bufsize);
8369 
8370 	VERIFY(0 == dmu_bonus_hold(spa->spa_meta_objset, obj, FTAG, &db));
8371 	dmu_buf_will_dirty(db, tx);
8372 	*(uint64_t *)db->db_data = nvsize;
8373 	dmu_buf_rele(db, FTAG);
8374 }
8375 
8376 static void
8377 spa_sync_aux_dev(spa_t *spa, spa_aux_vdev_t *sav, dmu_tx_t *tx,
8378     const char *config, const char *entry)
8379 {
8380 	nvlist_t *nvroot;
8381 	nvlist_t **list;
8382 	int i;
8383 
8384 	if (!sav->sav_sync)
8385 		return;
8386 
8387 	/*
8388 	 * Update the MOS nvlist describing the list of available devices.
8389 	 * spa_validate_aux() will have already made sure this nvlist is
8390 	 * valid and the vdevs are labeled appropriately.
8391 	 */
8392 	if (sav->sav_object == 0) {
8393 		sav->sav_object = dmu_object_alloc(spa->spa_meta_objset,
8394 		    DMU_OT_PACKED_NVLIST, 1 << 14, DMU_OT_PACKED_NVLIST_SIZE,
8395 		    sizeof (uint64_t), tx);
8396 		VERIFY(zap_update(spa->spa_meta_objset,
8397 		    DMU_POOL_DIRECTORY_OBJECT, entry, sizeof (uint64_t), 1,
8398 		    &sav->sav_object, tx) == 0);
8399 	}
8400 
8401 	VERIFY(nvlist_alloc(&nvroot, NV_UNIQUE_NAME, KM_SLEEP) == 0);
8402 	if (sav->sav_count == 0) {
8403 		VERIFY(nvlist_add_nvlist_array(nvroot, config, NULL, 0) == 0);
8404 	} else {
8405 		list = kmem_alloc(sav->sav_count*sizeof (void *), KM_SLEEP);
8406 		for (i = 0; i < sav->sav_count; i++)
8407 			list[i] = vdev_config_generate(spa, sav->sav_vdevs[i],
8408 			    B_FALSE, VDEV_CONFIG_L2CACHE);
8409 		VERIFY(nvlist_add_nvlist_array(nvroot, config, list,
8410 		    sav->sav_count) == 0);
8411 		for (i = 0; i < sav->sav_count; i++)
8412 			nvlist_free(list[i]);
8413 		kmem_free(list, sav->sav_count * sizeof (void *));
8414 	}
8415 
8416 	spa_sync_nvlist(spa, sav->sav_object, nvroot, tx);
8417 	nvlist_free(nvroot);
8418 
8419 	sav->sav_sync = B_FALSE;
8420 }
8421 
8422 /*
8423  * Rebuild spa's all-vdev ZAP from the vdev ZAPs indicated in each vdev_t.
8424  * The all-vdev ZAP must be empty.
8425  */
8426 static void
8427 spa_avz_build(vdev_t *vd, uint64_t avz, dmu_tx_t *tx)
8428 {
8429 	spa_t *spa = vd->vdev_spa;
8430 
8431 	if (vd->vdev_top_zap != 0) {
8432 		VERIFY0(zap_add_int(spa->spa_meta_objset, avz,
8433 		    vd->vdev_top_zap, tx));
8434 	}
8435 	if (vd->vdev_leaf_zap != 0) {
8436 		VERIFY0(zap_add_int(spa->spa_meta_objset, avz,
8437 		    vd->vdev_leaf_zap, tx));
8438 	}
8439 	for (uint64_t i = 0; i < vd->vdev_children; i++) {
8440 		spa_avz_build(vd->vdev_child[i], avz, tx);
8441 	}
8442 }
8443 
8444 static void
8445 spa_sync_config_object(spa_t *spa, dmu_tx_t *tx)
8446 {
8447 	nvlist_t *config;
8448 
8449 	/*
8450 	 * If the pool is being imported from a pre-per-vdev-ZAP version of ZFS,
8451 	 * its config may not be dirty but we still need to build per-vdev ZAPs.
8452 	 * Similarly, if the pool is being assembled (e.g. after a split), we
8453 	 * need to rebuild the AVZ although the config may not be dirty.
8454 	 */
8455 	if (list_is_empty(&spa->spa_config_dirty_list) &&
8456 	    spa->spa_avz_action == AVZ_ACTION_NONE)
8457 		return;
8458 
8459 	spa_config_enter(spa, SCL_STATE, FTAG, RW_READER);
8460 
8461 	ASSERT(spa->spa_avz_action == AVZ_ACTION_NONE ||
8462 	    spa->spa_avz_action == AVZ_ACTION_INITIALIZE ||
8463 	    spa->spa_all_vdev_zaps != 0);
8464 
8465 	if (spa->spa_avz_action == AVZ_ACTION_REBUILD) {
8466 		/* Make and build the new AVZ */
8467 		uint64_t new_avz = zap_create(spa->spa_meta_objset,
8468 		    DMU_OTN_ZAP_METADATA, DMU_OT_NONE, 0, tx);
8469 		spa_avz_build(spa->spa_root_vdev, new_avz, tx);
8470 
8471 		/* Diff old AVZ with new one */
8472 		zap_cursor_t zc;
8473 		zap_attribute_t za;
8474 
8475 		for (zap_cursor_init(&zc, spa->spa_meta_objset,
8476 		    spa->spa_all_vdev_zaps);
8477 		    zap_cursor_retrieve(&zc, &za) == 0;
8478 		    zap_cursor_advance(&zc)) {
8479 			uint64_t vdzap = za.za_first_integer;
8480 			if (zap_lookup_int(spa->spa_meta_objset, new_avz,
8481 			    vdzap) == ENOENT) {
8482 				/*
8483 				 * ZAP is listed in old AVZ but not in new one;
8484 				 * destroy it
8485 				 */
8486 				VERIFY0(zap_destroy(spa->spa_meta_objset, vdzap,
8487 				    tx));
8488 			}
8489 		}
8490 
8491 		zap_cursor_fini(&zc);
8492 
8493 		/* Destroy the old AVZ */
8494 		VERIFY0(zap_destroy(spa->spa_meta_objset,
8495 		    spa->spa_all_vdev_zaps, tx));
8496 
8497 		/* Replace the old AVZ in the dir obj with the new one */
8498 		VERIFY0(zap_update(spa->spa_meta_objset,
8499 		    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_VDEV_ZAP_MAP,
8500 		    sizeof (new_avz), 1, &new_avz, tx));
8501 
8502 		spa->spa_all_vdev_zaps = new_avz;
8503 	} else if (spa->spa_avz_action == AVZ_ACTION_DESTROY) {
8504 		zap_cursor_t zc;
8505 		zap_attribute_t za;
8506 
8507 		/* Walk through the AVZ and destroy all listed ZAPs */
8508 		for (zap_cursor_init(&zc, spa->spa_meta_objset,
8509 		    spa->spa_all_vdev_zaps);
8510 		    zap_cursor_retrieve(&zc, &za) == 0;
8511 		    zap_cursor_advance(&zc)) {
8512 			uint64_t zap = za.za_first_integer;
8513 			VERIFY0(zap_destroy(spa->spa_meta_objset, zap, tx));
8514 		}
8515 
8516 		zap_cursor_fini(&zc);
8517 
8518 		/* Destroy and unlink the AVZ itself */
8519 		VERIFY0(zap_destroy(spa->spa_meta_objset,
8520 		    spa->spa_all_vdev_zaps, tx));
8521 		VERIFY0(zap_remove(spa->spa_meta_objset,
8522 		    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_VDEV_ZAP_MAP, tx));
8523 		spa->spa_all_vdev_zaps = 0;
8524 	}
8525 
8526 	if (spa->spa_all_vdev_zaps == 0) {
8527 		spa->spa_all_vdev_zaps = zap_create_link(spa->spa_meta_objset,
8528 		    DMU_OTN_ZAP_METADATA, DMU_POOL_DIRECTORY_OBJECT,
8529 		    DMU_POOL_VDEV_ZAP_MAP, tx);
8530 	}
8531 	spa->spa_avz_action = AVZ_ACTION_NONE;
8532 
8533 	/* Create ZAPs for vdevs that don't have them. */
8534 	vdev_construct_zaps(spa->spa_root_vdev, tx);
8535 
8536 	config = spa_config_generate(spa, spa->spa_root_vdev,
8537 	    dmu_tx_get_txg(tx), B_FALSE);
8538 
8539 	/*
8540 	 * If we're upgrading the spa version then make sure that
8541 	 * the config object gets updated with the correct version.
8542 	 */
8543 	if (spa->spa_ubsync.ub_version < spa->spa_uberblock.ub_version)
8544 		fnvlist_add_uint64(config, ZPOOL_CONFIG_VERSION,
8545 		    spa->spa_uberblock.ub_version);
8546 
8547 	spa_config_exit(spa, SCL_STATE, FTAG);
8548 
8549 	nvlist_free(spa->spa_config_syncing);
8550 	spa->spa_config_syncing = config;
8551 
8552 	spa_sync_nvlist(spa, spa->spa_config_object, config, tx);
8553 }
8554 
8555 static void
8556 spa_sync_version(void *arg, dmu_tx_t *tx)
8557 {
8558 	uint64_t *versionp = arg;
8559 	uint64_t version = *versionp;
8560 	spa_t *spa = dmu_tx_pool(tx)->dp_spa;
8561 
8562 	/*
8563 	 * Setting the version is special cased when first creating the pool.
8564 	 */
8565 	ASSERT(tx->tx_txg != TXG_INITIAL);
8566 
8567 	ASSERT(SPA_VERSION_IS_SUPPORTED(version));
8568 	ASSERT(version >= spa_version(spa));
8569 
8570 	spa->spa_uberblock.ub_version = version;
8571 	vdev_config_dirty(spa->spa_root_vdev);
8572 	spa_history_log_internal(spa, "set", tx, "version=%lld",
8573 	    (longlong_t)version);
8574 }
8575 
8576 /*
8577  * Set zpool properties.
8578  */
8579 static void
8580 spa_sync_props(void *arg, dmu_tx_t *tx)
8581 {
8582 	nvlist_t *nvp = arg;
8583 	spa_t *spa = dmu_tx_pool(tx)->dp_spa;
8584 	objset_t *mos = spa->spa_meta_objset;
8585 	nvpair_t *elem = NULL;
8586 
8587 	mutex_enter(&spa->spa_props_lock);
8588 
8589 	while ((elem = nvlist_next_nvpair(nvp, elem))) {
8590 		uint64_t intval;
8591 		char *strval, *fname;
8592 		zpool_prop_t prop;
8593 		const char *propname;
8594 		zprop_type_t proptype;
8595 		spa_feature_t fid;
8596 
8597 		switch (prop = zpool_name_to_prop(nvpair_name(elem))) {
8598 		case ZPOOL_PROP_INVAL:
8599 			/*
8600 			 * We checked this earlier in spa_prop_validate().
8601 			 */
8602 			ASSERT(zpool_prop_feature(nvpair_name(elem)));
8603 
8604 			fname = strchr(nvpair_name(elem), '@') + 1;
8605 			VERIFY0(zfeature_lookup_name(fname, &fid));
8606 
8607 			spa_feature_enable(spa, fid, tx);
8608 			spa_history_log_internal(spa, "set", tx,
8609 			    "%s=enabled", nvpair_name(elem));
8610 			break;
8611 
8612 		case ZPOOL_PROP_VERSION:
8613 			intval = fnvpair_value_uint64(elem);
8614 			/*
8615 			 * The version is synced separately before other
8616 			 * properties and should be correct by now.
8617 			 */
8618 			ASSERT3U(spa_version(spa), >=, intval);
8619 			break;
8620 
8621 		case ZPOOL_PROP_ALTROOT:
8622 			/*
8623 			 * 'altroot' is a non-persistent property. It should
8624 			 * have been set temporarily at creation or import time.
8625 			 */
8626 			ASSERT(spa->spa_root != NULL);
8627 			break;
8628 
8629 		case ZPOOL_PROP_READONLY:
8630 		case ZPOOL_PROP_CACHEFILE:
8631 			/*
8632 			 * 'readonly' and 'cachefile' are also non-persistent
8633 			 * properties.
8634 			 */
8635 			break;
8636 		case ZPOOL_PROP_COMMENT:
8637 			strval = fnvpair_value_string(elem);
8638 			if (spa->spa_comment != NULL)
8639 				spa_strfree(spa->spa_comment);
8640 			spa->spa_comment = spa_strdup(strval);
8641 			/*
8642 			 * We need to dirty the configuration on all the vdevs
8643 			 * so that their labels get updated.  It's unnecessary
8644 			 * to do this for pool creation since the vdev's
8645 			 * configuration has already been dirtied.
8646 			 */
8647 			if (tx->tx_txg != TXG_INITIAL)
8648 				vdev_config_dirty(spa->spa_root_vdev);
8649 			spa_history_log_internal(spa, "set", tx,
8650 			    "%s=%s", nvpair_name(elem), strval);
8651 			break;
8652 		default:
8653 			/*
8654 			 * Set pool property values in the poolprops mos object.
8655 			 */
8656 			if (spa->spa_pool_props_object == 0) {
8657 				spa->spa_pool_props_object =
8658 				    zap_create_link(mos, DMU_OT_POOL_PROPS,
8659 				    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_PROPS,
8660 				    tx);
8661 			}
8662 
8663 			/* normalize the property name */
8664 			propname = zpool_prop_to_name(prop);
8665 			proptype = zpool_prop_get_type(prop);
8666 
8667 			if (nvpair_type(elem) == DATA_TYPE_STRING) {
8668 				ASSERT(proptype == PROP_TYPE_STRING);
8669 				strval = fnvpair_value_string(elem);
8670 				VERIFY0(zap_update(mos,
8671 				    spa->spa_pool_props_object, propname,
8672 				    1, strlen(strval) + 1, strval, tx));
8673 				spa_history_log_internal(spa, "set", tx,
8674 				    "%s=%s", nvpair_name(elem), strval);
8675 			} else if (nvpair_type(elem) == DATA_TYPE_UINT64) {
8676 				intval = fnvpair_value_uint64(elem);
8677 
8678 				if (proptype == PROP_TYPE_INDEX) {
8679 					const char *unused;
8680 					VERIFY0(zpool_prop_index_to_string(
8681 					    prop, intval, &unused));
8682 				}
8683 				VERIFY0(zap_update(mos,
8684 				    spa->spa_pool_props_object, propname,
8685 				    8, 1, &intval, tx));
8686 				spa_history_log_internal(spa, "set", tx,
8687 				    "%s=%lld", nvpair_name(elem),
8688 				    (longlong_t)intval);
8689 			} else {
8690 				ASSERT(0); /* not allowed */
8691 			}
8692 
8693 			switch (prop) {
8694 			case ZPOOL_PROP_DELEGATION:
8695 				spa->spa_delegation = intval;
8696 				break;
8697 			case ZPOOL_PROP_BOOTFS:
8698 				spa->spa_bootfs = intval;
8699 				break;
8700 			case ZPOOL_PROP_FAILUREMODE:
8701 				spa->spa_failmode = intval;
8702 				break;
8703 			case ZPOOL_PROP_AUTOTRIM:
8704 				spa->spa_autotrim = intval;
8705 				spa_async_request(spa,
8706 				    SPA_ASYNC_AUTOTRIM_RESTART);
8707 				break;
8708 			case ZPOOL_PROP_AUTOEXPAND:
8709 				spa->spa_autoexpand = intval;
8710 				if (tx->tx_txg != TXG_INITIAL)
8711 					spa_async_request(spa,
8712 					    SPA_ASYNC_AUTOEXPAND);
8713 				break;
8714 			case ZPOOL_PROP_MULTIHOST:
8715 				spa->spa_multihost = intval;
8716 				break;
8717 			default:
8718 				break;
8719 			}
8720 		}
8721 
8722 	}
8723 
8724 	mutex_exit(&spa->spa_props_lock);
8725 }
8726 
8727 /*
8728  * Perform one-time upgrade on-disk changes.  spa_version() does not
8729  * reflect the new version this txg, so there must be no changes this
8730  * txg to anything that the upgrade code depends on after it executes.
8731  * Therefore this must be called after dsl_pool_sync() does the sync
8732  * tasks.
8733  */
8734 static void
8735 spa_sync_upgrades(spa_t *spa, dmu_tx_t *tx)
8736 {
8737 	if (spa_sync_pass(spa) != 1)
8738 		return;
8739 
8740 	dsl_pool_t *dp = spa->spa_dsl_pool;
8741 	rrw_enter(&dp->dp_config_rwlock, RW_WRITER, FTAG);
8742 
8743 	if (spa->spa_ubsync.ub_version < SPA_VERSION_ORIGIN &&
8744 	    spa->spa_uberblock.ub_version >= SPA_VERSION_ORIGIN) {
8745 		dsl_pool_create_origin(dp, tx);
8746 
8747 		/* Keeping the origin open increases spa_minref */
8748 		spa->spa_minref += 3;
8749 	}
8750 
8751 	if (spa->spa_ubsync.ub_version < SPA_VERSION_NEXT_CLONES &&
8752 	    spa->spa_uberblock.ub_version >= SPA_VERSION_NEXT_CLONES) {
8753 		dsl_pool_upgrade_clones(dp, tx);
8754 	}
8755 
8756 	if (spa->spa_ubsync.ub_version < SPA_VERSION_DIR_CLONES &&
8757 	    spa->spa_uberblock.ub_version >= SPA_VERSION_DIR_CLONES) {
8758 		dsl_pool_upgrade_dir_clones(dp, tx);
8759 
8760 		/* Keeping the freedir open increases spa_minref */
8761 		spa->spa_minref += 3;
8762 	}
8763 
8764 	if (spa->spa_ubsync.ub_version < SPA_VERSION_FEATURES &&
8765 	    spa->spa_uberblock.ub_version >= SPA_VERSION_FEATURES) {
8766 		spa_feature_create_zap_objects(spa, tx);
8767 	}
8768 
8769 	/*
8770 	 * LZ4_COMPRESS feature's behaviour was changed to activate_on_enable
8771 	 * when possibility to use lz4 compression for metadata was added
8772 	 * Old pools that have this feature enabled must be upgraded to have
8773 	 * this feature active
8774 	 */
8775 	if (spa->spa_uberblock.ub_version >= SPA_VERSION_FEATURES) {
8776 		boolean_t lz4_en = spa_feature_is_enabled(spa,
8777 		    SPA_FEATURE_LZ4_COMPRESS);
8778 		boolean_t lz4_ac = spa_feature_is_active(spa,
8779 		    SPA_FEATURE_LZ4_COMPRESS);
8780 
8781 		if (lz4_en && !lz4_ac)
8782 			spa_feature_incr(spa, SPA_FEATURE_LZ4_COMPRESS, tx);
8783 	}
8784 
8785 	/*
8786 	 * If we haven't written the salt, do so now.  Note that the
8787 	 * feature may not be activated yet, but that's fine since
8788 	 * the presence of this ZAP entry is backwards compatible.
8789 	 */
8790 	if (zap_contains(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
8791 	    DMU_POOL_CHECKSUM_SALT) == ENOENT) {
8792 		VERIFY0(zap_add(spa->spa_meta_objset,
8793 		    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_CHECKSUM_SALT, 1,
8794 		    sizeof (spa->spa_cksum_salt.zcs_bytes),
8795 		    spa->spa_cksum_salt.zcs_bytes, tx));
8796 	}
8797 
8798 	rrw_exit(&dp->dp_config_rwlock, FTAG);
8799 }
8800 
8801 static void
8802 vdev_indirect_state_sync_verify(vdev_t *vd)
8803 {
8804 	vdev_indirect_mapping_t *vim __maybe_unused = vd->vdev_indirect_mapping;
8805 	vdev_indirect_births_t *vib __maybe_unused = vd->vdev_indirect_births;
8806 
8807 	if (vd->vdev_ops == &vdev_indirect_ops) {
8808 		ASSERT(vim != NULL);
8809 		ASSERT(vib != NULL);
8810 	}
8811 
8812 	uint64_t obsolete_sm_object = 0;
8813 	ASSERT0(vdev_obsolete_sm_object(vd, &obsolete_sm_object));
8814 	if (obsolete_sm_object != 0) {
8815 		ASSERT(vd->vdev_obsolete_sm != NULL);
8816 		ASSERT(vd->vdev_removing ||
8817 		    vd->vdev_ops == &vdev_indirect_ops);
8818 		ASSERT(vdev_indirect_mapping_num_entries(vim) > 0);
8819 		ASSERT(vdev_indirect_mapping_bytes_mapped(vim) > 0);
8820 		ASSERT3U(obsolete_sm_object, ==,
8821 		    space_map_object(vd->vdev_obsolete_sm));
8822 		ASSERT3U(vdev_indirect_mapping_bytes_mapped(vim), >=,
8823 		    space_map_allocated(vd->vdev_obsolete_sm));
8824 	}
8825 	ASSERT(vd->vdev_obsolete_segments != NULL);
8826 
8827 	/*
8828 	 * Since frees / remaps to an indirect vdev can only
8829 	 * happen in syncing context, the obsolete segments
8830 	 * tree must be empty when we start syncing.
8831 	 */
8832 	ASSERT0(range_tree_space(vd->vdev_obsolete_segments));
8833 }
8834 
8835 /*
8836  * Set the top-level vdev's max queue depth. Evaluate each top-level's
8837  * async write queue depth in case it changed. The max queue depth will
8838  * not change in the middle of syncing out this txg.
8839  */
8840 static void
8841 spa_sync_adjust_vdev_max_queue_depth(spa_t *spa)
8842 {
8843 	ASSERT(spa_writeable(spa));
8844 
8845 	vdev_t *rvd = spa->spa_root_vdev;
8846 	uint32_t max_queue_depth = zfs_vdev_async_write_max_active *
8847 	    zfs_vdev_queue_depth_pct / 100;
8848 	metaslab_class_t *normal = spa_normal_class(spa);
8849 	metaslab_class_t *special = spa_special_class(spa);
8850 	metaslab_class_t *dedup = spa_dedup_class(spa);
8851 
8852 	uint64_t slots_per_allocator = 0;
8853 	for (int c = 0; c < rvd->vdev_children; c++) {
8854 		vdev_t *tvd = rvd->vdev_child[c];
8855 
8856 		metaslab_group_t *mg = tvd->vdev_mg;
8857 		if (mg == NULL || !metaslab_group_initialized(mg))
8858 			continue;
8859 
8860 		metaslab_class_t *mc = mg->mg_class;
8861 		if (mc != normal && mc != special && mc != dedup)
8862 			continue;
8863 
8864 		/*
8865 		 * It is safe to do a lock-free check here because only async
8866 		 * allocations look at mg_max_alloc_queue_depth, and async
8867 		 * allocations all happen from spa_sync().
8868 		 */
8869 		for (int i = 0; i < mg->mg_allocators; i++) {
8870 			ASSERT0(zfs_refcount_count(
8871 			    &(mg->mg_allocator[i].mga_alloc_queue_depth)));
8872 		}
8873 		mg->mg_max_alloc_queue_depth = max_queue_depth;
8874 
8875 		for (int i = 0; i < mg->mg_allocators; i++) {
8876 			mg->mg_allocator[i].mga_cur_max_alloc_queue_depth =
8877 			    zfs_vdev_def_queue_depth;
8878 		}
8879 		slots_per_allocator += zfs_vdev_def_queue_depth;
8880 	}
8881 
8882 	for (int i = 0; i < spa->spa_alloc_count; i++) {
8883 		ASSERT0(zfs_refcount_count(&normal->mc_allocator[i].
8884 		    mca_alloc_slots));
8885 		ASSERT0(zfs_refcount_count(&special->mc_allocator[i].
8886 		    mca_alloc_slots));
8887 		ASSERT0(zfs_refcount_count(&dedup->mc_allocator[i].
8888 		    mca_alloc_slots));
8889 		normal->mc_allocator[i].mca_alloc_max_slots =
8890 		    slots_per_allocator;
8891 		special->mc_allocator[i].mca_alloc_max_slots =
8892 		    slots_per_allocator;
8893 		dedup->mc_allocator[i].mca_alloc_max_slots =
8894 		    slots_per_allocator;
8895 	}
8896 	normal->mc_alloc_throttle_enabled = zio_dva_throttle_enabled;
8897 	special->mc_alloc_throttle_enabled = zio_dva_throttle_enabled;
8898 	dedup->mc_alloc_throttle_enabled = zio_dva_throttle_enabled;
8899 }
8900 
8901 static void
8902 spa_sync_condense_indirect(spa_t *spa, dmu_tx_t *tx)
8903 {
8904 	ASSERT(spa_writeable(spa));
8905 
8906 	vdev_t *rvd = spa->spa_root_vdev;
8907 	for (int c = 0; c < rvd->vdev_children; c++) {
8908 		vdev_t *vd = rvd->vdev_child[c];
8909 		vdev_indirect_state_sync_verify(vd);
8910 
8911 		if (vdev_indirect_should_condense(vd)) {
8912 			spa_condense_indirect_start_sync(vd, tx);
8913 			break;
8914 		}
8915 	}
8916 }
8917 
8918 static void
8919 spa_sync_iterate_to_convergence(spa_t *spa, dmu_tx_t *tx)
8920 {
8921 	objset_t *mos = spa->spa_meta_objset;
8922 	dsl_pool_t *dp = spa->spa_dsl_pool;
8923 	uint64_t txg = tx->tx_txg;
8924 	bplist_t *free_bpl = &spa->spa_free_bplist[txg & TXG_MASK];
8925 
8926 	do {
8927 		int pass = ++spa->spa_sync_pass;
8928 
8929 		spa_sync_config_object(spa, tx);
8930 		spa_sync_aux_dev(spa, &spa->spa_spares, tx,
8931 		    ZPOOL_CONFIG_SPARES, DMU_POOL_SPARES);
8932 		spa_sync_aux_dev(spa, &spa->spa_l2cache, tx,
8933 		    ZPOOL_CONFIG_L2CACHE, DMU_POOL_L2CACHE);
8934 		spa_errlog_sync(spa, txg);
8935 		dsl_pool_sync(dp, txg);
8936 
8937 		if (pass < zfs_sync_pass_deferred_free ||
8938 		    spa_feature_is_active(spa, SPA_FEATURE_LOG_SPACEMAP)) {
8939 			/*
8940 			 * If the log space map feature is active we don't
8941 			 * care about deferred frees and the deferred bpobj
8942 			 * as the log space map should effectively have the
8943 			 * same results (i.e. appending only to one object).
8944 			 */
8945 			spa_sync_frees(spa, free_bpl, tx);
8946 		} else {
8947 			/*
8948 			 * We can not defer frees in pass 1, because
8949 			 * we sync the deferred frees later in pass 1.
8950 			 */
8951 			ASSERT3U(pass, >, 1);
8952 			bplist_iterate(free_bpl, bpobj_enqueue_alloc_cb,
8953 			    &spa->spa_deferred_bpobj, tx);
8954 		}
8955 
8956 		ddt_sync(spa, txg);
8957 		dsl_scan_sync(dp, tx);
8958 		svr_sync(spa, tx);
8959 		spa_sync_upgrades(spa, tx);
8960 
8961 		spa_flush_metaslabs(spa, tx);
8962 
8963 		vdev_t *vd = NULL;
8964 		while ((vd = txg_list_remove(&spa->spa_vdev_txg_list, txg))
8965 		    != NULL)
8966 			vdev_sync(vd, txg);
8967 
8968 		/*
8969 		 * Note: We need to check if the MOS is dirty because we could
8970 		 * have marked the MOS dirty without updating the uberblock
8971 		 * (e.g. if we have sync tasks but no dirty user data). We need
8972 		 * to check the uberblock's rootbp because it is updated if we
8973 		 * have synced out dirty data (though in this case the MOS will
8974 		 * most likely also be dirty due to second order effects, we
8975 		 * don't want to rely on that here).
8976 		 */
8977 		if (pass == 1 &&
8978 		    spa->spa_uberblock.ub_rootbp.blk_birth < txg &&
8979 		    !dmu_objset_is_dirty(mos, txg)) {
8980 			/*
8981 			 * Nothing changed on the first pass, therefore this
8982 			 * TXG is a no-op. Avoid syncing deferred frees, so
8983 			 * that we can keep this TXG as a no-op.
8984 			 */
8985 			ASSERT(txg_list_empty(&dp->dp_dirty_datasets, txg));
8986 			ASSERT(txg_list_empty(&dp->dp_dirty_dirs, txg));
8987 			ASSERT(txg_list_empty(&dp->dp_sync_tasks, txg));
8988 			ASSERT(txg_list_empty(&dp->dp_early_sync_tasks, txg));
8989 			break;
8990 		}
8991 
8992 		spa_sync_deferred_frees(spa, tx);
8993 	} while (dmu_objset_is_dirty(mos, txg));
8994 }
8995 
8996 /*
8997  * Rewrite the vdev configuration (which includes the uberblock) to
8998  * commit the transaction group.
8999  *
9000  * If there are no dirty vdevs, we sync the uberblock to a few random
9001  * top-level vdevs that are known to be visible in the config cache
9002  * (see spa_vdev_add() for a complete description). If there *are* dirty
9003  * vdevs, sync the uberblock to all vdevs.
9004  */
9005 static void
9006 spa_sync_rewrite_vdev_config(spa_t *spa, dmu_tx_t *tx)
9007 {
9008 	vdev_t *rvd = spa->spa_root_vdev;
9009 	uint64_t txg = tx->tx_txg;
9010 
9011 	for (;;) {
9012 		int error = 0;
9013 
9014 		/*
9015 		 * We hold SCL_STATE to prevent vdev open/close/etc.
9016 		 * while we're attempting to write the vdev labels.
9017 		 */
9018 		spa_config_enter(spa, SCL_STATE, FTAG, RW_READER);
9019 
9020 		if (list_is_empty(&spa->spa_config_dirty_list)) {
9021 			vdev_t *svd[SPA_SYNC_MIN_VDEVS] = { NULL };
9022 			int svdcount = 0;
9023 			int children = rvd->vdev_children;
9024 			int c0 = spa_get_random(children);
9025 
9026 			for (int c = 0; c < children; c++) {
9027 				vdev_t *vd =
9028 				    rvd->vdev_child[(c0 + c) % children];
9029 
9030 				/* Stop when revisiting the first vdev */
9031 				if (c > 0 && svd[0] == vd)
9032 					break;
9033 
9034 				if (vd->vdev_ms_array == 0 ||
9035 				    vd->vdev_islog ||
9036 				    !vdev_is_concrete(vd))
9037 					continue;
9038 
9039 				svd[svdcount++] = vd;
9040 				if (svdcount == SPA_SYNC_MIN_VDEVS)
9041 					break;
9042 			}
9043 			error = vdev_config_sync(svd, svdcount, txg);
9044 		} else {
9045 			error = vdev_config_sync(rvd->vdev_child,
9046 			    rvd->vdev_children, txg);
9047 		}
9048 
9049 		if (error == 0)
9050 			spa->spa_last_synced_guid = rvd->vdev_guid;
9051 
9052 		spa_config_exit(spa, SCL_STATE, FTAG);
9053 
9054 		if (error == 0)
9055 			break;
9056 		zio_suspend(spa, NULL, ZIO_SUSPEND_IOERR);
9057 		zio_resume_wait(spa);
9058 	}
9059 }
9060 
9061 /*
9062  * Sync the specified transaction group.  New blocks may be dirtied as
9063  * part of the process, so we iterate until it converges.
9064  */
9065 void
9066 spa_sync(spa_t *spa, uint64_t txg)
9067 {
9068 	vdev_t *vd = NULL;
9069 
9070 	VERIFY(spa_writeable(spa));
9071 
9072 	/*
9073 	 * Wait for i/os issued in open context that need to complete
9074 	 * before this txg syncs.
9075 	 */
9076 	(void) zio_wait(spa->spa_txg_zio[txg & TXG_MASK]);
9077 	spa->spa_txg_zio[txg & TXG_MASK] = zio_root(spa, NULL, NULL,
9078 	    ZIO_FLAG_CANFAIL);
9079 
9080 	/*
9081 	 * Lock out configuration changes.
9082 	 */
9083 	spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER);
9084 
9085 	spa->spa_syncing_txg = txg;
9086 	spa->spa_sync_pass = 0;
9087 
9088 	for (int i = 0; i < spa->spa_alloc_count; i++) {
9089 		mutex_enter(&spa->spa_alloc_locks[i]);
9090 		VERIFY0(avl_numnodes(&spa->spa_alloc_trees[i]));
9091 		mutex_exit(&spa->spa_alloc_locks[i]);
9092 	}
9093 
9094 	/*
9095 	 * If there are any pending vdev state changes, convert them
9096 	 * into config changes that go out with this transaction group.
9097 	 */
9098 	spa_config_enter(spa, SCL_STATE, FTAG, RW_READER);
9099 	while (list_head(&spa->spa_state_dirty_list) != NULL) {
9100 		/*
9101 		 * We need the write lock here because, for aux vdevs,
9102 		 * calling vdev_config_dirty() modifies sav_config.
9103 		 * This is ugly and will become unnecessary when we
9104 		 * eliminate the aux vdev wart by integrating all vdevs
9105 		 * into the root vdev tree.
9106 		 */
9107 		spa_config_exit(spa, SCL_CONFIG | SCL_STATE, FTAG);
9108 		spa_config_enter(spa, SCL_CONFIG | SCL_STATE, FTAG, RW_WRITER);
9109 		while ((vd = list_head(&spa->spa_state_dirty_list)) != NULL) {
9110 			vdev_state_clean(vd);
9111 			vdev_config_dirty(vd);
9112 		}
9113 		spa_config_exit(spa, SCL_CONFIG | SCL_STATE, FTAG);
9114 		spa_config_enter(spa, SCL_CONFIG | SCL_STATE, FTAG, RW_READER);
9115 	}
9116 	spa_config_exit(spa, SCL_STATE, FTAG);
9117 
9118 	dsl_pool_t *dp = spa->spa_dsl_pool;
9119 	dmu_tx_t *tx = dmu_tx_create_assigned(dp, txg);
9120 
9121 	spa->spa_sync_starttime = gethrtime();
9122 	taskq_cancel_id(system_delay_taskq, spa->spa_deadman_tqid);
9123 	spa->spa_deadman_tqid = taskq_dispatch_delay(system_delay_taskq,
9124 	    spa_deadman, spa, TQ_SLEEP, ddi_get_lbolt() +
9125 	    NSEC_TO_TICK(spa->spa_deadman_synctime));
9126 
9127 	/*
9128 	 * If we are upgrading to SPA_VERSION_RAIDZ_DEFLATE this txg,
9129 	 * set spa_deflate if we have no raid-z vdevs.
9130 	 */
9131 	if (spa->spa_ubsync.ub_version < SPA_VERSION_RAIDZ_DEFLATE &&
9132 	    spa->spa_uberblock.ub_version >= SPA_VERSION_RAIDZ_DEFLATE) {
9133 		vdev_t *rvd = spa->spa_root_vdev;
9134 
9135 		int i;
9136 		for (i = 0; i < rvd->vdev_children; i++) {
9137 			vd = rvd->vdev_child[i];
9138 			if (vd->vdev_deflate_ratio != SPA_MINBLOCKSIZE)
9139 				break;
9140 		}
9141 		if (i == rvd->vdev_children) {
9142 			spa->spa_deflate = TRUE;
9143 			VERIFY0(zap_add(spa->spa_meta_objset,
9144 			    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_DEFLATE,
9145 			    sizeof (uint64_t), 1, &spa->spa_deflate, tx));
9146 		}
9147 	}
9148 
9149 	spa_sync_adjust_vdev_max_queue_depth(spa);
9150 
9151 	spa_sync_condense_indirect(spa, tx);
9152 
9153 	spa_sync_iterate_to_convergence(spa, tx);
9154 
9155 #ifdef ZFS_DEBUG
9156 	if (!list_is_empty(&spa->spa_config_dirty_list)) {
9157 	/*
9158 	 * Make sure that the number of ZAPs for all the vdevs matches
9159 	 * the number of ZAPs in the per-vdev ZAP list. This only gets
9160 	 * called if the config is dirty; otherwise there may be
9161 	 * outstanding AVZ operations that weren't completed in
9162 	 * spa_sync_config_object.
9163 	 */
9164 		uint64_t all_vdev_zap_entry_count;
9165 		ASSERT0(zap_count(spa->spa_meta_objset,
9166 		    spa->spa_all_vdev_zaps, &all_vdev_zap_entry_count));
9167 		ASSERT3U(vdev_count_verify_zaps(spa->spa_root_vdev), ==,
9168 		    all_vdev_zap_entry_count);
9169 	}
9170 #endif
9171 
9172 	if (spa->spa_vdev_removal != NULL) {
9173 		ASSERT0(spa->spa_vdev_removal->svr_bytes_done[txg & TXG_MASK]);
9174 	}
9175 
9176 	spa_sync_rewrite_vdev_config(spa, tx);
9177 	dmu_tx_commit(tx);
9178 
9179 	taskq_cancel_id(system_delay_taskq, spa->spa_deadman_tqid);
9180 	spa->spa_deadman_tqid = 0;
9181 
9182 	/*
9183 	 * Clear the dirty config list.
9184 	 */
9185 	while ((vd = list_head(&spa->spa_config_dirty_list)) != NULL)
9186 		vdev_config_clean(vd);
9187 
9188 	/*
9189 	 * Now that the new config has synced transactionally,
9190 	 * let it become visible to the config cache.
9191 	 */
9192 	if (spa->spa_config_syncing != NULL) {
9193 		spa_config_set(spa, spa->spa_config_syncing);
9194 		spa->spa_config_txg = txg;
9195 		spa->spa_config_syncing = NULL;
9196 	}
9197 
9198 	dsl_pool_sync_done(dp, txg);
9199 
9200 	for (int i = 0; i < spa->spa_alloc_count; i++) {
9201 		mutex_enter(&spa->spa_alloc_locks[i]);
9202 		VERIFY0(avl_numnodes(&spa->spa_alloc_trees[i]));
9203 		mutex_exit(&spa->spa_alloc_locks[i]);
9204 	}
9205 
9206 	/*
9207 	 * Update usable space statistics.
9208 	 */
9209 	while ((vd = txg_list_remove(&spa->spa_vdev_txg_list, TXG_CLEAN(txg)))
9210 	    != NULL)
9211 		vdev_sync_done(vd, txg);
9212 
9213 	metaslab_class_evict_old(spa->spa_normal_class, txg);
9214 	metaslab_class_evict_old(spa->spa_log_class, txg);
9215 
9216 	spa_sync_close_syncing_log_sm(spa);
9217 
9218 	spa_update_dspace(spa);
9219 
9220 	/*
9221 	 * It had better be the case that we didn't dirty anything
9222 	 * since vdev_config_sync().
9223 	 */
9224 	ASSERT(txg_list_empty(&dp->dp_dirty_datasets, txg));
9225 	ASSERT(txg_list_empty(&dp->dp_dirty_dirs, txg));
9226 	ASSERT(txg_list_empty(&spa->spa_vdev_txg_list, txg));
9227 
9228 	while (zfs_pause_spa_sync)
9229 		delay(1);
9230 
9231 	spa->spa_sync_pass = 0;
9232 
9233 	/*
9234 	 * Update the last synced uberblock here. We want to do this at
9235 	 * the end of spa_sync() so that consumers of spa_last_synced_txg()
9236 	 * will be guaranteed that all the processing associated with
9237 	 * that txg has been completed.
9238 	 */
9239 	spa->spa_ubsync = spa->spa_uberblock;
9240 	spa_config_exit(spa, SCL_CONFIG, FTAG);
9241 
9242 	spa_handle_ignored_writes(spa);
9243 
9244 	/*
9245 	 * If any async tasks have been requested, kick them off.
9246 	 */
9247 	spa_async_dispatch(spa);
9248 }
9249 
9250 /*
9251  * Sync all pools.  We don't want to hold the namespace lock across these
9252  * operations, so we take a reference on the spa_t and drop the lock during the
9253  * sync.
9254  */
9255 void
9256 spa_sync_allpools(void)
9257 {
9258 	spa_t *spa = NULL;
9259 	mutex_enter(&spa_namespace_lock);
9260 	while ((spa = spa_next(spa)) != NULL) {
9261 		if (spa_state(spa) != POOL_STATE_ACTIVE ||
9262 		    !spa_writeable(spa) || spa_suspended(spa))
9263 			continue;
9264 		spa_open_ref(spa, FTAG);
9265 		mutex_exit(&spa_namespace_lock);
9266 		txg_wait_synced(spa_get_dsl(spa), 0);
9267 		mutex_enter(&spa_namespace_lock);
9268 		spa_close(spa, FTAG);
9269 	}
9270 	mutex_exit(&spa_namespace_lock);
9271 }
9272 
9273 /*
9274  * ==========================================================================
9275  * Miscellaneous routines
9276  * ==========================================================================
9277  */
9278 
9279 /*
9280  * Remove all pools in the system.
9281  */
9282 void
9283 spa_evict_all(void)
9284 {
9285 	spa_t *spa;
9286 
9287 	/*
9288 	 * Remove all cached state.  All pools should be closed now,
9289 	 * so every spa in the AVL tree should be unreferenced.
9290 	 */
9291 	mutex_enter(&spa_namespace_lock);
9292 	while ((spa = spa_next(NULL)) != NULL) {
9293 		/*
9294 		 * Stop async tasks.  The async thread may need to detach
9295 		 * a device that's been replaced, which requires grabbing
9296 		 * spa_namespace_lock, so we must drop it here.
9297 		 */
9298 		spa_open_ref(spa, FTAG);
9299 		mutex_exit(&spa_namespace_lock);
9300 		spa_async_suspend(spa);
9301 		mutex_enter(&spa_namespace_lock);
9302 		spa_close(spa, FTAG);
9303 
9304 		if (spa->spa_state != POOL_STATE_UNINITIALIZED) {
9305 			spa_unload(spa);
9306 			spa_deactivate(spa);
9307 		}
9308 		spa_remove(spa);
9309 	}
9310 	mutex_exit(&spa_namespace_lock);
9311 }
9312 
9313 vdev_t *
9314 spa_lookup_by_guid(spa_t *spa, uint64_t guid, boolean_t aux)
9315 {
9316 	vdev_t *vd;
9317 	int i;
9318 
9319 	if ((vd = vdev_lookup_by_guid(spa->spa_root_vdev, guid)) != NULL)
9320 		return (vd);
9321 
9322 	if (aux) {
9323 		for (i = 0; i < spa->spa_l2cache.sav_count; i++) {
9324 			vd = spa->spa_l2cache.sav_vdevs[i];
9325 			if (vd->vdev_guid == guid)
9326 				return (vd);
9327 		}
9328 
9329 		for (i = 0; i < spa->spa_spares.sav_count; i++) {
9330 			vd = spa->spa_spares.sav_vdevs[i];
9331 			if (vd->vdev_guid == guid)
9332 				return (vd);
9333 		}
9334 	}
9335 
9336 	return (NULL);
9337 }
9338 
9339 void
9340 spa_upgrade(spa_t *spa, uint64_t version)
9341 {
9342 	ASSERT(spa_writeable(spa));
9343 
9344 	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
9345 
9346 	/*
9347 	 * This should only be called for a non-faulted pool, and since a
9348 	 * future version would result in an unopenable pool, this shouldn't be
9349 	 * possible.
9350 	 */
9351 	ASSERT(SPA_VERSION_IS_SUPPORTED(spa->spa_uberblock.ub_version));
9352 	ASSERT3U(version, >=, spa->spa_uberblock.ub_version);
9353 
9354 	spa->spa_uberblock.ub_version = version;
9355 	vdev_config_dirty(spa->spa_root_vdev);
9356 
9357 	spa_config_exit(spa, SCL_ALL, FTAG);
9358 
9359 	txg_wait_synced(spa_get_dsl(spa), 0);
9360 }
9361 
9362 boolean_t
9363 spa_has_spare(spa_t *spa, uint64_t guid)
9364 {
9365 	int i;
9366 	uint64_t spareguid;
9367 	spa_aux_vdev_t *sav = &spa->spa_spares;
9368 
9369 	for (i = 0; i < sav->sav_count; i++)
9370 		if (sav->sav_vdevs[i]->vdev_guid == guid)
9371 			return (B_TRUE);
9372 
9373 	for (i = 0; i < sav->sav_npending; i++) {
9374 		if (nvlist_lookup_uint64(sav->sav_pending[i], ZPOOL_CONFIG_GUID,
9375 		    &spareguid) == 0 && spareguid == guid)
9376 			return (B_TRUE);
9377 	}
9378 
9379 	return (B_FALSE);
9380 }
9381 
9382 /*
9383  * Check if a pool has an active shared spare device.
9384  * Note: reference count of an active spare is 2, as a spare and as a replace
9385  */
9386 static boolean_t
9387 spa_has_active_shared_spare(spa_t *spa)
9388 {
9389 	int i, refcnt;
9390 	uint64_t pool;
9391 	spa_aux_vdev_t *sav = &spa->spa_spares;
9392 
9393 	for (i = 0; i < sav->sav_count; i++) {
9394 		if (spa_spare_exists(sav->sav_vdevs[i]->vdev_guid, &pool,
9395 		    &refcnt) && pool != 0ULL && pool == spa_guid(spa) &&
9396 		    refcnt > 2)
9397 			return (B_TRUE);
9398 	}
9399 
9400 	return (B_FALSE);
9401 }
9402 
9403 uint64_t
9404 spa_total_metaslabs(spa_t *spa)
9405 {
9406 	vdev_t *rvd = spa->spa_root_vdev;
9407 
9408 	uint64_t m = 0;
9409 	for (uint64_t c = 0; c < rvd->vdev_children; c++) {
9410 		vdev_t *vd = rvd->vdev_child[c];
9411 		if (!vdev_is_concrete(vd))
9412 			continue;
9413 		m += vd->vdev_ms_count;
9414 	}
9415 	return (m);
9416 }
9417 
9418 /*
9419  * Notify any waiting threads that some activity has switched from being in-
9420  * progress to not-in-progress so that the thread can wake up and determine
9421  * whether it is finished waiting.
9422  */
9423 void
9424 spa_notify_waiters(spa_t *spa)
9425 {
9426 	/*
9427 	 * Acquiring spa_activities_lock here prevents the cv_broadcast from
9428 	 * happening between the waiting thread's check and cv_wait.
9429 	 */
9430 	mutex_enter(&spa->spa_activities_lock);
9431 	cv_broadcast(&spa->spa_activities_cv);
9432 	mutex_exit(&spa->spa_activities_lock);
9433 }
9434 
9435 /*
9436  * Notify any waiting threads that the pool is exporting, and then block until
9437  * they are finished using the spa_t.
9438  */
9439 void
9440 spa_wake_waiters(spa_t *spa)
9441 {
9442 	mutex_enter(&spa->spa_activities_lock);
9443 	spa->spa_waiters_cancel = B_TRUE;
9444 	cv_broadcast(&spa->spa_activities_cv);
9445 	while (spa->spa_waiters != 0)
9446 		cv_wait(&spa->spa_waiters_cv, &spa->spa_activities_lock);
9447 	spa->spa_waiters_cancel = B_FALSE;
9448 	mutex_exit(&spa->spa_activities_lock);
9449 }
9450 
9451 /* Whether the vdev or any of its descendants are being initialized/trimmed. */
9452 static boolean_t
9453 spa_vdev_activity_in_progress_impl(vdev_t *vd, zpool_wait_activity_t activity)
9454 {
9455 	spa_t *spa = vd->vdev_spa;
9456 
9457 	ASSERT(spa_config_held(spa, SCL_CONFIG | SCL_STATE, RW_READER));
9458 	ASSERT(MUTEX_HELD(&spa->spa_activities_lock));
9459 	ASSERT(activity == ZPOOL_WAIT_INITIALIZE ||
9460 	    activity == ZPOOL_WAIT_TRIM);
9461 
9462 	kmutex_t *lock = activity == ZPOOL_WAIT_INITIALIZE ?
9463 	    &vd->vdev_initialize_lock : &vd->vdev_trim_lock;
9464 
9465 	mutex_exit(&spa->spa_activities_lock);
9466 	mutex_enter(lock);
9467 	mutex_enter(&spa->spa_activities_lock);
9468 
9469 	boolean_t in_progress = (activity == ZPOOL_WAIT_INITIALIZE) ?
9470 	    (vd->vdev_initialize_state == VDEV_INITIALIZE_ACTIVE) :
9471 	    (vd->vdev_trim_state == VDEV_TRIM_ACTIVE);
9472 	mutex_exit(lock);
9473 
9474 	if (in_progress)
9475 		return (B_TRUE);
9476 
9477 	for (int i = 0; i < vd->vdev_children; i++) {
9478 		if (spa_vdev_activity_in_progress_impl(vd->vdev_child[i],
9479 		    activity))
9480 			return (B_TRUE);
9481 	}
9482 
9483 	return (B_FALSE);
9484 }
9485 
9486 /*
9487  * If use_guid is true, this checks whether the vdev specified by guid is
9488  * being initialized/trimmed. Otherwise, it checks whether any vdev in the pool
9489  * is being initialized/trimmed. The caller must hold the config lock and
9490  * spa_activities_lock.
9491  */
9492 static int
9493 spa_vdev_activity_in_progress(spa_t *spa, boolean_t use_guid, uint64_t guid,
9494     zpool_wait_activity_t activity, boolean_t *in_progress)
9495 {
9496 	mutex_exit(&spa->spa_activities_lock);
9497 	spa_config_enter(spa, SCL_CONFIG | SCL_STATE, FTAG, RW_READER);
9498 	mutex_enter(&spa->spa_activities_lock);
9499 
9500 	vdev_t *vd;
9501 	if (use_guid) {
9502 		vd = spa_lookup_by_guid(spa, guid, B_FALSE);
9503 		if (vd == NULL || !vd->vdev_ops->vdev_op_leaf) {
9504 			spa_config_exit(spa, SCL_CONFIG | SCL_STATE, FTAG);
9505 			return (EINVAL);
9506 		}
9507 	} else {
9508 		vd = spa->spa_root_vdev;
9509 	}
9510 
9511 	*in_progress = spa_vdev_activity_in_progress_impl(vd, activity);
9512 
9513 	spa_config_exit(spa, SCL_CONFIG | SCL_STATE, FTAG);
9514 	return (0);
9515 }
9516 
9517 /*
9518  * Locking for waiting threads
9519  * ---------------------------
9520  *
9521  * Waiting threads need a way to check whether a given activity is in progress,
9522  * and then, if it is, wait for it to complete. Each activity will have some
9523  * in-memory representation of the relevant on-disk state which can be used to
9524  * determine whether or not the activity is in progress. The in-memory state and
9525  * the locking used to protect it will be different for each activity, and may
9526  * not be suitable for use with a cvar (e.g., some state is protected by the
9527  * config lock). To allow waiting threads to wait without any races, another
9528  * lock, spa_activities_lock, is used.
9529  *
9530  * When the state is checked, both the activity-specific lock (if there is one)
9531  * and spa_activities_lock are held. In some cases, the activity-specific lock
9532  * is acquired explicitly (e.g. the config lock). In others, the locking is
9533  * internal to some check (e.g. bpobj_is_empty). After checking, the waiting
9534  * thread releases the activity-specific lock and, if the activity is in
9535  * progress, then cv_waits using spa_activities_lock.
9536  *
9537  * The waiting thread is woken when another thread, one completing some
9538  * activity, updates the state of the activity and then calls
9539  * spa_notify_waiters, which will cv_broadcast. This 'completing' thread only
9540  * needs to hold its activity-specific lock when updating the state, and this
9541  * lock can (but doesn't have to) be dropped before calling spa_notify_waiters.
9542  *
9543  * Because spa_notify_waiters acquires spa_activities_lock before broadcasting,
9544  * and because it is held when the waiting thread checks the state of the
9545  * activity, it can never be the case that the completing thread both updates
9546  * the activity state and cv_broadcasts in between the waiting thread's check
9547  * and cv_wait. Thus, a waiting thread can never miss a wakeup.
9548  *
9549  * In order to prevent deadlock, when the waiting thread does its check, in some
9550  * cases it will temporarily drop spa_activities_lock in order to acquire the
9551  * activity-specific lock. The order in which spa_activities_lock and the
9552  * activity specific lock are acquired in the waiting thread is determined by
9553  * the order in which they are acquired in the completing thread; if the
9554  * completing thread calls spa_notify_waiters with the activity-specific lock
9555  * held, then the waiting thread must also acquire the activity-specific lock
9556  * first.
9557  */
9558 
9559 static int
9560 spa_activity_in_progress(spa_t *spa, zpool_wait_activity_t activity,
9561     boolean_t use_tag, uint64_t tag, boolean_t *in_progress)
9562 {
9563 	int error = 0;
9564 
9565 	ASSERT(MUTEX_HELD(&spa->spa_activities_lock));
9566 
9567 	switch (activity) {
9568 	case ZPOOL_WAIT_CKPT_DISCARD:
9569 		*in_progress =
9570 		    (spa_feature_is_active(spa, SPA_FEATURE_POOL_CHECKPOINT) &&
9571 		    zap_contains(spa_meta_objset(spa),
9572 		    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_ZPOOL_CHECKPOINT) ==
9573 		    ENOENT);
9574 		break;
9575 	case ZPOOL_WAIT_FREE:
9576 		*in_progress = ((spa_version(spa) >= SPA_VERSION_DEADLISTS &&
9577 		    !bpobj_is_empty(&spa->spa_dsl_pool->dp_free_bpobj)) ||
9578 		    spa_feature_is_active(spa, SPA_FEATURE_ASYNC_DESTROY) ||
9579 		    spa_livelist_delete_check(spa));
9580 		break;
9581 	case ZPOOL_WAIT_INITIALIZE:
9582 	case ZPOOL_WAIT_TRIM:
9583 		error = spa_vdev_activity_in_progress(spa, use_tag, tag,
9584 		    activity, in_progress);
9585 		break;
9586 	case ZPOOL_WAIT_REPLACE:
9587 		mutex_exit(&spa->spa_activities_lock);
9588 		spa_config_enter(spa, SCL_CONFIG | SCL_STATE, FTAG, RW_READER);
9589 		mutex_enter(&spa->spa_activities_lock);
9590 
9591 		*in_progress = vdev_replace_in_progress(spa->spa_root_vdev);
9592 		spa_config_exit(spa, SCL_CONFIG | SCL_STATE, FTAG);
9593 		break;
9594 	case ZPOOL_WAIT_REMOVE:
9595 		*in_progress = (spa->spa_removing_phys.sr_state ==
9596 		    DSS_SCANNING);
9597 		break;
9598 	case ZPOOL_WAIT_RESILVER:
9599 		if ((*in_progress = vdev_rebuild_active(spa->spa_root_vdev)))
9600 			break;
9601 		/* fall through */
9602 	case ZPOOL_WAIT_SCRUB:
9603 	{
9604 		boolean_t scanning, paused, is_scrub;
9605 		dsl_scan_t *scn =  spa->spa_dsl_pool->dp_scan;
9606 
9607 		is_scrub = (scn->scn_phys.scn_func == POOL_SCAN_SCRUB);
9608 		scanning = (scn->scn_phys.scn_state == DSS_SCANNING);
9609 		paused = dsl_scan_is_paused_scrub(scn);
9610 		*in_progress = (scanning && !paused &&
9611 		    is_scrub == (activity == ZPOOL_WAIT_SCRUB));
9612 		break;
9613 	}
9614 	default:
9615 		panic("unrecognized value for activity %d", activity);
9616 	}
9617 
9618 	return (error);
9619 }
9620 
9621 static int
9622 spa_wait_common(const char *pool, zpool_wait_activity_t activity,
9623     boolean_t use_tag, uint64_t tag, boolean_t *waited)
9624 {
9625 	/*
9626 	 * The tag is used to distinguish between instances of an activity.
9627 	 * 'initialize' and 'trim' are the only activities that we use this for.
9628 	 * The other activities can only have a single instance in progress in a
9629 	 * pool at one time, making the tag unnecessary.
9630 	 *
9631 	 * There can be multiple devices being replaced at once, but since they
9632 	 * all finish once resilvering finishes, we don't bother keeping track
9633 	 * of them individually, we just wait for them all to finish.
9634 	 */
9635 	if (use_tag && activity != ZPOOL_WAIT_INITIALIZE &&
9636 	    activity != ZPOOL_WAIT_TRIM)
9637 		return (EINVAL);
9638 
9639 	if (activity < 0 || activity >= ZPOOL_WAIT_NUM_ACTIVITIES)
9640 		return (EINVAL);
9641 
9642 	spa_t *spa;
9643 	int error = spa_open(pool, &spa, FTAG);
9644 	if (error != 0)
9645 		return (error);
9646 
9647 	/*
9648 	 * Increment the spa's waiter count so that we can call spa_close and
9649 	 * still ensure that the spa_t doesn't get freed before this thread is
9650 	 * finished with it when the pool is exported. We want to call spa_close
9651 	 * before we start waiting because otherwise the additional ref would
9652 	 * prevent the pool from being exported or destroyed throughout the
9653 	 * potentially long wait.
9654 	 */
9655 	mutex_enter(&spa->spa_activities_lock);
9656 	spa->spa_waiters++;
9657 	spa_close(spa, FTAG);
9658 
9659 	*waited = B_FALSE;
9660 	for (;;) {
9661 		boolean_t in_progress;
9662 		error = spa_activity_in_progress(spa, activity, use_tag, tag,
9663 		    &in_progress);
9664 
9665 		if (error || !in_progress || spa->spa_waiters_cancel)
9666 			break;
9667 
9668 		*waited = B_TRUE;
9669 
9670 		if (cv_wait_sig(&spa->spa_activities_cv,
9671 		    &spa->spa_activities_lock) == 0) {
9672 			error = EINTR;
9673 			break;
9674 		}
9675 	}
9676 
9677 	spa->spa_waiters--;
9678 	cv_signal(&spa->spa_waiters_cv);
9679 	mutex_exit(&spa->spa_activities_lock);
9680 
9681 	return (error);
9682 }
9683 
9684 /*
9685  * Wait for a particular instance of the specified activity to complete, where
9686  * the instance is identified by 'tag'
9687  */
9688 int
9689 spa_wait_tag(const char *pool, zpool_wait_activity_t activity, uint64_t tag,
9690     boolean_t *waited)
9691 {
9692 	return (spa_wait_common(pool, activity, B_TRUE, tag, waited));
9693 }
9694 
9695 /*
9696  * Wait for all instances of the specified activity complete
9697  */
9698 int
9699 spa_wait(const char *pool, zpool_wait_activity_t activity, boolean_t *waited)
9700 {
9701 
9702 	return (spa_wait_common(pool, activity, B_FALSE, 0, waited));
9703 }
9704 
9705 sysevent_t *
9706 spa_event_create(spa_t *spa, vdev_t *vd, nvlist_t *hist_nvl, const char *name)
9707 {
9708 	sysevent_t *ev = NULL;
9709 #ifdef _KERNEL
9710 	nvlist_t *resource;
9711 
9712 	resource = zfs_event_create(spa, vd, FM_SYSEVENT_CLASS, name, hist_nvl);
9713 	if (resource) {
9714 		ev = kmem_alloc(sizeof (sysevent_t), KM_SLEEP);
9715 		ev->resource = resource;
9716 	}
9717 #endif
9718 	return (ev);
9719 }
9720 
9721 void
9722 spa_event_post(sysevent_t *ev)
9723 {
9724 #ifdef _KERNEL
9725 	if (ev) {
9726 		zfs_zevent_post(ev->resource, NULL, zfs_zevent_post_cb);
9727 		kmem_free(ev, sizeof (*ev));
9728 	}
9729 #endif
9730 }
9731 
9732 /*
9733  * Post a zevent corresponding to the given sysevent.   The 'name' must be one
9734  * of the event definitions in sys/sysevent/eventdefs.h.  The payload will be
9735  * filled in from the spa and (optionally) the vdev.  This doesn't do anything
9736  * in the userland libzpool, as we don't want consumers to misinterpret ztest
9737  * or zdb as real changes.
9738  */
9739 void
9740 spa_event_notify(spa_t *spa, vdev_t *vd, nvlist_t *hist_nvl, const char *name)
9741 {
9742 	spa_event_post(spa_event_create(spa, vd, hist_nvl, name));
9743 }
9744 
9745 /* state manipulation functions */
9746 EXPORT_SYMBOL(spa_open);
9747 EXPORT_SYMBOL(spa_open_rewind);
9748 EXPORT_SYMBOL(spa_get_stats);
9749 EXPORT_SYMBOL(spa_create);
9750 EXPORT_SYMBOL(spa_import);
9751 EXPORT_SYMBOL(spa_tryimport);
9752 EXPORT_SYMBOL(spa_destroy);
9753 EXPORT_SYMBOL(spa_export);
9754 EXPORT_SYMBOL(spa_reset);
9755 EXPORT_SYMBOL(spa_async_request);
9756 EXPORT_SYMBOL(spa_async_suspend);
9757 EXPORT_SYMBOL(spa_async_resume);
9758 EXPORT_SYMBOL(spa_inject_addref);
9759 EXPORT_SYMBOL(spa_inject_delref);
9760 EXPORT_SYMBOL(spa_scan_stat_init);
9761 EXPORT_SYMBOL(spa_scan_get_stats);
9762 
9763 /* device manipulation */
9764 EXPORT_SYMBOL(spa_vdev_add);
9765 EXPORT_SYMBOL(spa_vdev_attach);
9766 EXPORT_SYMBOL(spa_vdev_detach);
9767 EXPORT_SYMBOL(spa_vdev_setpath);
9768 EXPORT_SYMBOL(spa_vdev_setfru);
9769 EXPORT_SYMBOL(spa_vdev_split_mirror);
9770 
9771 /* spare statech is global across all pools) */
9772 EXPORT_SYMBOL(spa_spare_add);
9773 EXPORT_SYMBOL(spa_spare_remove);
9774 EXPORT_SYMBOL(spa_spare_exists);
9775 EXPORT_SYMBOL(spa_spare_activate);
9776 
9777 /* L2ARC statech is global across all pools) */
9778 EXPORT_SYMBOL(spa_l2cache_add);
9779 EXPORT_SYMBOL(spa_l2cache_remove);
9780 EXPORT_SYMBOL(spa_l2cache_exists);
9781 EXPORT_SYMBOL(spa_l2cache_activate);
9782 EXPORT_SYMBOL(spa_l2cache_drop);
9783 
9784 /* scanning */
9785 EXPORT_SYMBOL(spa_scan);
9786 EXPORT_SYMBOL(spa_scan_stop);
9787 
9788 /* spa syncing */
9789 EXPORT_SYMBOL(spa_sync); /* only for DMU use */
9790 EXPORT_SYMBOL(spa_sync_allpools);
9791 
9792 /* properties */
9793 EXPORT_SYMBOL(spa_prop_set);
9794 EXPORT_SYMBOL(spa_prop_get);
9795 EXPORT_SYMBOL(spa_prop_clear_bootfs);
9796 
9797 /* asynchronous event notification */
9798 EXPORT_SYMBOL(spa_event_notify);
9799 
9800 /* BEGIN CSTYLED */
9801 ZFS_MODULE_PARAM(zfs_spa, spa_, load_verify_shift, INT, ZMOD_RW,
9802 	"log2(fraction of arc that can be used by inflight I/Os when "
9803 	"verifying pool during import");
9804 
9805 ZFS_MODULE_PARAM(zfs_spa, spa_, load_verify_metadata, INT, ZMOD_RW,
9806 	"Set to traverse metadata on pool import");
9807 
9808 ZFS_MODULE_PARAM(zfs_spa, spa_, load_verify_data, INT, ZMOD_RW,
9809 	"Set to traverse data on pool import");
9810 
9811 ZFS_MODULE_PARAM(zfs_spa, spa_, load_print_vdev_tree, INT, ZMOD_RW,
9812 	"Print vdev tree to zfs_dbgmsg during pool import");
9813 
9814 ZFS_MODULE_PARAM(zfs_zio, zio_, taskq_batch_pct, UINT, ZMOD_RD,
9815 	"Percentage of CPUs to run an IO worker thread");
9816 
9817 ZFS_MODULE_PARAM(zfs, zfs_, max_missing_tvds, ULONG, ZMOD_RW,
9818 	"Allow importing pool with up to this number of missing top-level "
9819 	"vdevs (in read-only mode)");
9820 
9821 ZFS_MODULE_PARAM(zfs_livelist_condense, zfs_livelist_condense_, zthr_pause, INT, ZMOD_RW,
9822 	"Set the livelist condense zthr to pause");
9823 
9824 ZFS_MODULE_PARAM(zfs_livelist_condense, zfs_livelist_condense_, sync_pause, INT, ZMOD_RW,
9825 	"Set the livelist condense synctask to pause");
9826 
9827 ZFS_MODULE_PARAM(zfs_livelist_condense, zfs_livelist_condense_, sync_cancel, INT, ZMOD_RW,
9828 	"Whether livelist condensing was canceled in the synctask");
9829 
9830 ZFS_MODULE_PARAM(zfs_livelist_condense, zfs_livelist_condense_, zthr_cancel, INT, ZMOD_RW,
9831 	"Whether livelist condensing was canceled in the zthr function");
9832 
9833 ZFS_MODULE_PARAM(zfs_livelist_condense, zfs_livelist_condense_, new_alloc, INT, ZMOD_RW,
9834 	"Whether extra ALLOC blkptrs were added to a livelist entry while it "
9835 	"was being condensed");
9836 /* END CSTYLED */
9837