xref: /titanic_44/usr/src/uts/common/fs/zfs/spa_misc.c (revision 283b84606b6fc326692c03273de1774e8c122f9a)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23  * Copyright (c) 2012 by Delphix. All rights reserved.
24  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
25  */
26 
27 #include <sys/zfs_context.h>
28 #include <sys/spa_impl.h>
29 #include <sys/spa_boot.h>
30 #include <sys/zio.h>
31 #include <sys/zio_checksum.h>
32 #include <sys/zio_compress.h>
33 #include <sys/dmu.h>
34 #include <sys/dmu_tx.h>
35 #include <sys/zap.h>
36 #include <sys/zil.h>
37 #include <sys/vdev_impl.h>
38 #include <sys/metaslab.h>
39 #include <sys/uberblock_impl.h>
40 #include <sys/txg.h>
41 #include <sys/avl.h>
42 #include <sys/unique.h>
43 #include <sys/dsl_pool.h>
44 #include <sys/dsl_dir.h>
45 #include <sys/dsl_prop.h>
46 #include <sys/dsl_scan.h>
47 #include <sys/fs/zfs.h>
48 #include <sys/metaslab_impl.h>
49 #include <sys/arc.h>
50 #include <sys/ddt.h>
51 #include "zfs_prop.h"
52 #include "zfeature_common.h"
53 
54 /*
55  * SPA locking
56  *
57  * There are four basic locks for managing spa_t structures:
58  *
59  * spa_namespace_lock (global mutex)
60  *
61  *	This lock must be acquired to do any of the following:
62  *
63  *		- Lookup a spa_t by name
64  *		- Add or remove a spa_t from the namespace
65  *		- Increase spa_refcount from non-zero
66  *		- Check if spa_refcount is zero
67  *		- Rename a spa_t
68  *		- add/remove/attach/detach devices
69  *		- Held for the duration of create/destroy/import/export
70  *
71  *	It does not need to handle recursion.  A create or destroy may
72  *	reference objects (files or zvols) in other pools, but by
73  *	definition they must have an existing reference, and will never need
74  *	to lookup a spa_t by name.
75  *
76  * spa_refcount (per-spa refcount_t protected by mutex)
77  *
78  *	This reference count keep track of any active users of the spa_t.  The
79  *	spa_t cannot be destroyed or freed while this is non-zero.  Internally,
80  *	the refcount is never really 'zero' - opening a pool implicitly keeps
81  *	some references in the DMU.  Internally we check against spa_minref, but
82  *	present the image of a zero/non-zero value to consumers.
83  *
84  * spa_config_lock[] (per-spa array of rwlocks)
85  *
86  *	This protects the spa_t from config changes, and must be held in
87  *	the following circumstances:
88  *
89  *		- RW_READER to perform I/O to the spa
90  *		- RW_WRITER to change the vdev config
91  *
92  * The locking order is fairly straightforward:
93  *
94  *		spa_namespace_lock	->	spa_refcount
95  *
96  *	The namespace lock must be acquired to increase the refcount from 0
97  *	or to check if it is zero.
98  *
99  *		spa_refcount		->	spa_config_lock[]
100  *
101  *	There must be at least one valid reference on the spa_t to acquire
102  *	the config lock.
103  *
104  *		spa_namespace_lock	->	spa_config_lock[]
105  *
106  *	The namespace lock must always be taken before the config lock.
107  *
108  *
109  * The spa_namespace_lock can be acquired directly and is globally visible.
110  *
111  * The namespace is manipulated using the following functions, all of which
112  * require the spa_namespace_lock to be held.
113  *
114  *	spa_lookup()		Lookup a spa_t by name.
115  *
116  *	spa_add()		Create a new spa_t in the namespace.
117  *
118  *	spa_remove()		Remove a spa_t from the namespace.  This also
119  *				frees up any memory associated with the spa_t.
120  *
121  *	spa_next()		Returns the next spa_t in the system, or the
122  *				first if NULL is passed.
123  *
124  *	spa_evict_all()		Shutdown and remove all spa_t structures in
125  *				the system.
126  *
127  *	spa_guid_exists()	Determine whether a pool/device guid exists.
128  *
129  * The spa_refcount is manipulated using the following functions:
130  *
131  *	spa_open_ref()		Adds a reference to the given spa_t.  Must be
132  *				called with spa_namespace_lock held if the
133  *				refcount is currently zero.
134  *
135  *	spa_close()		Remove a reference from the spa_t.  This will
136  *				not free the spa_t or remove it from the
137  *				namespace.  No locking is required.
138  *
139  *	spa_refcount_zero()	Returns true if the refcount is currently
140  *				zero.  Must be called with spa_namespace_lock
141  *				held.
142  *
143  * The spa_config_lock[] is an array of rwlocks, ordered as follows:
144  * SCL_CONFIG > SCL_STATE > SCL_ALLOC > SCL_ZIO > SCL_FREE > SCL_VDEV.
145  * spa_config_lock[] is manipulated with spa_config_{enter,exit,held}().
146  *
147  * To read the configuration, it suffices to hold one of these locks as reader.
148  * To modify the configuration, you must hold all locks as writer.  To modify
149  * vdev state without altering the vdev tree's topology (e.g. online/offline),
150  * you must hold SCL_STATE and SCL_ZIO as writer.
151  *
152  * We use these distinct config locks to avoid recursive lock entry.
153  * For example, spa_sync() (which holds SCL_CONFIG as reader) induces
154  * block allocations (SCL_ALLOC), which may require reading space maps
155  * from disk (dmu_read() -> zio_read() -> SCL_ZIO).
156  *
157  * The spa config locks cannot be normal rwlocks because we need the
158  * ability to hand off ownership.  For example, SCL_ZIO is acquired
159  * by the issuing thread and later released by an interrupt thread.
160  * They do, however, obey the usual write-wanted semantics to prevent
161  * writer (i.e. system administrator) starvation.
162  *
163  * The lock acquisition rules are as follows:
164  *
165  * SCL_CONFIG
166  *	Protects changes to the vdev tree topology, such as vdev
167  *	add/remove/attach/detach.  Protects the dirty config list
168  *	(spa_config_dirty_list) and the set of spares and l2arc devices.
169  *
170  * SCL_STATE
171  *	Protects changes to pool state and vdev state, such as vdev
172  *	online/offline/fault/degrade/clear.  Protects the dirty state list
173  *	(spa_state_dirty_list) and global pool state (spa_state).
174  *
175  * SCL_ALLOC
176  *	Protects changes to metaslab groups and classes.
177  *	Held as reader by metaslab_alloc() and metaslab_claim().
178  *
179  * SCL_ZIO
180  *	Held by bp-level zios (those which have no io_vd upon entry)
181  *	to prevent changes to the vdev tree.  The bp-level zio implicitly
182  *	protects all of its vdev child zios, which do not hold SCL_ZIO.
183  *
184  * SCL_FREE
185  *	Protects changes to metaslab groups and classes.
186  *	Held as reader by metaslab_free().  SCL_FREE is distinct from
187  *	SCL_ALLOC, and lower than SCL_ZIO, so that we can safely free
188  *	blocks in zio_done() while another i/o that holds either
189  *	SCL_ALLOC or SCL_ZIO is waiting for this i/o to complete.
190  *
191  * SCL_VDEV
192  *	Held as reader to prevent changes to the vdev tree during trivial
193  *	inquiries such as bp_get_dsize().  SCL_VDEV is distinct from the
194  *	other locks, and lower than all of them, to ensure that it's safe
195  *	to acquire regardless of caller context.
196  *
197  * In addition, the following rules apply:
198  *
199  * (a)	spa_props_lock protects pool properties, spa_config and spa_config_list.
200  *	The lock ordering is SCL_CONFIG > spa_props_lock.
201  *
202  * (b)	I/O operations on leaf vdevs.  For any zio operation that takes
203  *	an explicit vdev_t argument -- such as zio_ioctl(), zio_read_phys(),
204  *	or zio_write_phys() -- the caller must ensure that the config cannot
205  *	cannot change in the interim, and that the vdev cannot be reopened.
206  *	SCL_STATE as reader suffices for both.
207  *
208  * The vdev configuration is protected by spa_vdev_enter() / spa_vdev_exit().
209  *
210  *	spa_vdev_enter()	Acquire the namespace lock and the config lock
211  *				for writing.
212  *
213  *	spa_vdev_exit()		Release the config lock, wait for all I/O
214  *				to complete, sync the updated configs to the
215  *				cache, and release the namespace lock.
216  *
217  * vdev state is protected by spa_vdev_state_enter() / spa_vdev_state_exit().
218  * Like spa_vdev_enter/exit, these are convenience wrappers -- the actual
219  * locking is, always, based on spa_namespace_lock and spa_config_lock[].
220  *
221  * spa_rename() is also implemented within this file since it requires
222  * manipulation of the namespace.
223  */
224 
225 static avl_tree_t spa_namespace_avl;
226 kmutex_t spa_namespace_lock;
227 static kcondvar_t spa_namespace_cv;
228 static int spa_active_count;
229 int spa_max_replication_override = SPA_DVAS_PER_BP;
230 
231 static kmutex_t spa_spare_lock;
232 static avl_tree_t spa_spare_avl;
233 static kmutex_t spa_l2cache_lock;
234 static avl_tree_t spa_l2cache_avl;
235 
236 kmem_cache_t *spa_buffer_pool;
237 int spa_mode_global;
238 
239 #ifdef ZFS_DEBUG
240 /* Everything except dprintf is on by default in debug builds */
241 int zfs_flags = ~ZFS_DEBUG_DPRINTF;
242 #else
243 int zfs_flags = 0;
244 #endif
245 
246 /*
247  * zfs_recover can be set to nonzero to attempt to recover from
248  * otherwise-fatal errors, typically caused by on-disk corruption.  When
249  * set, calls to zfs_panic_recover() will turn into warning messages.
250  */
251 int zfs_recover = 0;
252 
253 extern int zfs_txg_synctime_ms;
254 
255 /*
256  * Expiration time in units of zfs_txg_synctime_ms. This value has two
257  * meanings. First it is used to determine when the spa_deadman logic
258  * should fire. By default the spa_deadman will fire if spa_sync has
259  * not completed in 1000 * zfs_txg_synctime_ms (i.e. 1000 seconds).
260  * Secondly, the value determines if an I/O is considered "hung".
261  * Any I/O that has not completed in zfs_deadman_synctime is considered
262  * "hung" resulting in a system panic.
263  * 1000 zfs_txg_synctime_ms (i.e. 1000 seconds).
264  */
265 uint64_t zfs_deadman_synctime = 1000ULL;
266 
267 /*
268  * Override the zfs deadman behavior via /etc/system. By default the
269  * deadman is enabled except on VMware and sparc deployments.
270  */
271 int zfs_deadman_enabled = -1;
272 
273 
274 /*
275  * ==========================================================================
276  * SPA config locking
277  * ==========================================================================
278  */
279 static void
280 spa_config_lock_init(spa_t *spa)
281 {
282 	for (int i = 0; i < SCL_LOCKS; i++) {
283 		spa_config_lock_t *scl = &spa->spa_config_lock[i];
284 		mutex_init(&scl->scl_lock, NULL, MUTEX_DEFAULT, NULL);
285 		cv_init(&scl->scl_cv, NULL, CV_DEFAULT, NULL);
286 		refcount_create(&scl->scl_count);
287 		scl->scl_writer = NULL;
288 		scl->scl_write_wanted = 0;
289 	}
290 }
291 
292 static void
293 spa_config_lock_destroy(spa_t *spa)
294 {
295 	for (int i = 0; i < SCL_LOCKS; i++) {
296 		spa_config_lock_t *scl = &spa->spa_config_lock[i];
297 		mutex_destroy(&scl->scl_lock);
298 		cv_destroy(&scl->scl_cv);
299 		refcount_destroy(&scl->scl_count);
300 		ASSERT(scl->scl_writer == NULL);
301 		ASSERT(scl->scl_write_wanted == 0);
302 	}
303 }
304 
305 int
306 spa_config_tryenter(spa_t *spa, int locks, void *tag, krw_t rw)
307 {
308 	for (int i = 0; i < SCL_LOCKS; i++) {
309 		spa_config_lock_t *scl = &spa->spa_config_lock[i];
310 		if (!(locks & (1 << i)))
311 			continue;
312 		mutex_enter(&scl->scl_lock);
313 		if (rw == RW_READER) {
314 			if (scl->scl_writer || scl->scl_write_wanted) {
315 				mutex_exit(&scl->scl_lock);
316 				spa_config_exit(spa, locks ^ (1 << i), tag);
317 				return (0);
318 			}
319 		} else {
320 			ASSERT(scl->scl_writer != curthread);
321 			if (!refcount_is_zero(&scl->scl_count)) {
322 				mutex_exit(&scl->scl_lock);
323 				spa_config_exit(spa, locks ^ (1 << i), tag);
324 				return (0);
325 			}
326 			scl->scl_writer = curthread;
327 		}
328 		(void) refcount_add(&scl->scl_count, tag);
329 		mutex_exit(&scl->scl_lock);
330 	}
331 	return (1);
332 }
333 
334 void
335 spa_config_enter(spa_t *spa, int locks, void *tag, krw_t rw)
336 {
337 	int wlocks_held = 0;
338 
339 	for (int i = 0; i < SCL_LOCKS; i++) {
340 		spa_config_lock_t *scl = &spa->spa_config_lock[i];
341 		if (scl->scl_writer == curthread)
342 			wlocks_held |= (1 << i);
343 		if (!(locks & (1 << i)))
344 			continue;
345 		mutex_enter(&scl->scl_lock);
346 		if (rw == RW_READER) {
347 			while (scl->scl_writer || scl->scl_write_wanted) {
348 				cv_wait(&scl->scl_cv, &scl->scl_lock);
349 			}
350 		} else {
351 			ASSERT(scl->scl_writer != curthread);
352 			while (!refcount_is_zero(&scl->scl_count)) {
353 				scl->scl_write_wanted++;
354 				cv_wait(&scl->scl_cv, &scl->scl_lock);
355 				scl->scl_write_wanted--;
356 			}
357 			scl->scl_writer = curthread;
358 		}
359 		(void) refcount_add(&scl->scl_count, tag);
360 		mutex_exit(&scl->scl_lock);
361 	}
362 	ASSERT(wlocks_held <= locks);
363 }
364 
365 void
366 spa_config_exit(spa_t *spa, int locks, void *tag)
367 {
368 	for (int i = SCL_LOCKS - 1; i >= 0; i--) {
369 		spa_config_lock_t *scl = &spa->spa_config_lock[i];
370 		if (!(locks & (1 << i)))
371 			continue;
372 		mutex_enter(&scl->scl_lock);
373 		ASSERT(!refcount_is_zero(&scl->scl_count));
374 		if (refcount_remove(&scl->scl_count, tag) == 0) {
375 			ASSERT(scl->scl_writer == NULL ||
376 			    scl->scl_writer == curthread);
377 			scl->scl_writer = NULL;	/* OK in either case */
378 			cv_broadcast(&scl->scl_cv);
379 		}
380 		mutex_exit(&scl->scl_lock);
381 	}
382 }
383 
384 int
385 spa_config_held(spa_t *spa, int locks, krw_t rw)
386 {
387 	int locks_held = 0;
388 
389 	for (int i = 0; i < SCL_LOCKS; i++) {
390 		spa_config_lock_t *scl = &spa->spa_config_lock[i];
391 		if (!(locks & (1 << i)))
392 			continue;
393 		if ((rw == RW_READER && !refcount_is_zero(&scl->scl_count)) ||
394 		    (rw == RW_WRITER && scl->scl_writer == curthread))
395 			locks_held |= 1 << i;
396 	}
397 
398 	return (locks_held);
399 }
400 
401 /*
402  * ==========================================================================
403  * SPA namespace functions
404  * ==========================================================================
405  */
406 
407 /*
408  * Lookup the named spa_t in the AVL tree.  The spa_namespace_lock must be held.
409  * Returns NULL if no matching spa_t is found.
410  */
411 spa_t *
412 spa_lookup(const char *name)
413 {
414 	static spa_t search;	/* spa_t is large; don't allocate on stack */
415 	spa_t *spa;
416 	avl_index_t where;
417 	char c;
418 	char *cp;
419 
420 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
421 
422 	/*
423 	 * If it's a full dataset name, figure out the pool name and
424 	 * just use that.
425 	 */
426 	cp = strpbrk(name, "/@");
427 	if (cp) {
428 		c = *cp;
429 		*cp = '\0';
430 	}
431 
432 	(void) strlcpy(search.spa_name, name, sizeof (search.spa_name));
433 	spa = avl_find(&spa_namespace_avl, &search, &where);
434 
435 	if (cp)
436 		*cp = c;
437 
438 	return (spa);
439 }
440 
441 /*
442  * Fires when spa_sync has not completed within zfs_deadman_synctime_ms.
443  * If the zfs_deadman_enabled flag is set then it inspects all vdev queues
444  * looking for potentially hung I/Os.
445  */
446 void
447 spa_deadman(void *arg)
448 {
449 	spa_t *spa = arg;
450 
451 	zfs_dbgmsg("slow spa_sync: started %llu seconds ago, calls %llu",
452 	    (gethrtime() - spa->spa_sync_starttime) / NANOSEC,
453 	    ++spa->spa_deadman_calls);
454 	if (zfs_deadman_enabled)
455 		vdev_deadman(spa->spa_root_vdev);
456 }
457 
458 /*
459  * Create an uninitialized spa_t with the given name.  Requires
460  * spa_namespace_lock.  The caller must ensure that the spa_t doesn't already
461  * exist by calling spa_lookup() first.
462  */
463 spa_t *
464 spa_add(const char *name, nvlist_t *config, const char *altroot)
465 {
466 	spa_t *spa;
467 	spa_config_dirent_t *dp;
468 	cyc_handler_t hdlr;
469 	cyc_time_t when;
470 
471 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
472 
473 	spa = kmem_zalloc(sizeof (spa_t), KM_SLEEP);
474 
475 	mutex_init(&spa->spa_async_lock, NULL, MUTEX_DEFAULT, NULL);
476 	mutex_init(&spa->spa_errlist_lock, NULL, MUTEX_DEFAULT, NULL);
477 	mutex_init(&spa->spa_errlog_lock, NULL, MUTEX_DEFAULT, NULL);
478 	mutex_init(&spa->spa_history_lock, NULL, MUTEX_DEFAULT, NULL);
479 	mutex_init(&spa->spa_proc_lock, NULL, MUTEX_DEFAULT, NULL);
480 	mutex_init(&spa->spa_props_lock, NULL, MUTEX_DEFAULT, NULL);
481 	mutex_init(&spa->spa_scrub_lock, NULL, MUTEX_DEFAULT, NULL);
482 	mutex_init(&spa->spa_suspend_lock, NULL, MUTEX_DEFAULT, NULL);
483 	mutex_init(&spa->spa_vdev_top_lock, NULL, MUTEX_DEFAULT, NULL);
484 
485 	cv_init(&spa->spa_async_cv, NULL, CV_DEFAULT, NULL);
486 	cv_init(&spa->spa_proc_cv, NULL, CV_DEFAULT, NULL);
487 	cv_init(&spa->spa_scrub_io_cv, NULL, CV_DEFAULT, NULL);
488 	cv_init(&spa->spa_suspend_cv, NULL, CV_DEFAULT, NULL);
489 
490 	for (int t = 0; t < TXG_SIZE; t++)
491 		bplist_create(&spa->spa_free_bplist[t]);
492 
493 	(void) strlcpy(spa->spa_name, name, sizeof (spa->spa_name));
494 	spa->spa_state = POOL_STATE_UNINITIALIZED;
495 	spa->spa_freeze_txg = UINT64_MAX;
496 	spa->spa_final_txg = UINT64_MAX;
497 	spa->spa_load_max_txg = UINT64_MAX;
498 	spa->spa_proc = &p0;
499 	spa->spa_proc_state = SPA_PROC_NONE;
500 
501 	hdlr.cyh_func = spa_deadman;
502 	hdlr.cyh_arg = spa;
503 	hdlr.cyh_level = CY_LOW_LEVEL;
504 
505 	spa->spa_deadman_synctime = zfs_deadman_synctime *
506 	    zfs_txg_synctime_ms * MICROSEC;
507 
508 	/*
509 	 * This determines how often we need to check for hung I/Os after
510 	 * the cyclic has already fired. Since checking for hung I/Os is
511 	 * an expensive operation we don't want to check too frequently.
512 	 * Instead wait for 5 synctimes before checking again.
513 	 */
514 	when.cyt_interval = 5ULL * zfs_txg_synctime_ms * MICROSEC;
515 	when.cyt_when = CY_INFINITY;
516 	mutex_enter(&cpu_lock);
517 	spa->spa_deadman_cycid = cyclic_add(&hdlr, &when);
518 	mutex_exit(&cpu_lock);
519 
520 	refcount_create(&spa->spa_refcount);
521 	spa_config_lock_init(spa);
522 
523 	avl_add(&spa_namespace_avl, spa);
524 
525 	/*
526 	 * Set the alternate root, if there is one.
527 	 */
528 	if (altroot) {
529 		spa->spa_root = spa_strdup(altroot);
530 		spa_active_count++;
531 	}
532 
533 	/*
534 	 * Every pool starts with the default cachefile
535 	 */
536 	list_create(&spa->spa_config_list, sizeof (spa_config_dirent_t),
537 	    offsetof(spa_config_dirent_t, scd_link));
538 
539 	dp = kmem_zalloc(sizeof (spa_config_dirent_t), KM_SLEEP);
540 	dp->scd_path = altroot ? NULL : spa_strdup(spa_config_path);
541 	list_insert_head(&spa->spa_config_list, dp);
542 
543 	VERIFY(nvlist_alloc(&spa->spa_load_info, NV_UNIQUE_NAME,
544 	    KM_SLEEP) == 0);
545 
546 	if (config != NULL) {
547 		nvlist_t *features;
548 
549 		if (nvlist_lookup_nvlist(config, ZPOOL_CONFIG_FEATURES_FOR_READ,
550 		    &features) == 0) {
551 			VERIFY(nvlist_dup(features, &spa->spa_label_features,
552 			    0) == 0);
553 		}
554 
555 		VERIFY(nvlist_dup(config, &spa->spa_config, 0) == 0);
556 	}
557 
558 	if (spa->spa_label_features == NULL) {
559 		VERIFY(nvlist_alloc(&spa->spa_label_features, NV_UNIQUE_NAME,
560 		    KM_SLEEP) == 0);
561 	}
562 
563 	return (spa);
564 }
565 
566 /*
567  * Removes a spa_t from the namespace, freeing up any memory used.  Requires
568  * spa_namespace_lock.  This is called only after the spa_t has been closed and
569  * deactivated.
570  */
571 void
572 spa_remove(spa_t *spa)
573 {
574 	spa_config_dirent_t *dp;
575 
576 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
577 	ASSERT(spa->spa_state == POOL_STATE_UNINITIALIZED);
578 
579 	nvlist_free(spa->spa_config_splitting);
580 
581 	avl_remove(&spa_namespace_avl, spa);
582 	cv_broadcast(&spa_namespace_cv);
583 
584 	if (spa->spa_root) {
585 		spa_strfree(spa->spa_root);
586 		spa_active_count--;
587 	}
588 
589 	while ((dp = list_head(&spa->spa_config_list)) != NULL) {
590 		list_remove(&spa->spa_config_list, dp);
591 		if (dp->scd_path != NULL)
592 			spa_strfree(dp->scd_path);
593 		kmem_free(dp, sizeof (spa_config_dirent_t));
594 	}
595 
596 	list_destroy(&spa->spa_config_list);
597 
598 	nvlist_free(spa->spa_label_features);
599 	nvlist_free(spa->spa_load_info);
600 	spa_config_set(spa, NULL);
601 
602 	mutex_enter(&cpu_lock);
603 	if (spa->spa_deadman_cycid != CYCLIC_NONE)
604 		cyclic_remove(spa->spa_deadman_cycid);
605 	mutex_exit(&cpu_lock);
606 	spa->spa_deadman_cycid = CYCLIC_NONE;
607 
608 	refcount_destroy(&spa->spa_refcount);
609 
610 	spa_config_lock_destroy(spa);
611 
612 	for (int t = 0; t < TXG_SIZE; t++)
613 		bplist_destroy(&spa->spa_free_bplist[t]);
614 
615 	cv_destroy(&spa->spa_async_cv);
616 	cv_destroy(&spa->spa_proc_cv);
617 	cv_destroy(&spa->spa_scrub_io_cv);
618 	cv_destroy(&spa->spa_suspend_cv);
619 
620 	mutex_destroy(&spa->spa_async_lock);
621 	mutex_destroy(&spa->spa_errlist_lock);
622 	mutex_destroy(&spa->spa_errlog_lock);
623 	mutex_destroy(&spa->spa_history_lock);
624 	mutex_destroy(&spa->spa_proc_lock);
625 	mutex_destroy(&spa->spa_props_lock);
626 	mutex_destroy(&spa->spa_scrub_lock);
627 	mutex_destroy(&spa->spa_suspend_lock);
628 	mutex_destroy(&spa->spa_vdev_top_lock);
629 
630 	kmem_free(spa, sizeof (spa_t));
631 }
632 
633 /*
634  * Given a pool, return the next pool in the namespace, or NULL if there is
635  * none.  If 'prev' is NULL, return the first pool.
636  */
637 spa_t *
638 spa_next(spa_t *prev)
639 {
640 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
641 
642 	if (prev)
643 		return (AVL_NEXT(&spa_namespace_avl, prev));
644 	else
645 		return (avl_first(&spa_namespace_avl));
646 }
647 
648 /*
649  * ==========================================================================
650  * SPA refcount functions
651  * ==========================================================================
652  */
653 
654 /*
655  * Add a reference to the given spa_t.  Must have at least one reference, or
656  * have the namespace lock held.
657  */
658 void
659 spa_open_ref(spa_t *spa, void *tag)
660 {
661 	ASSERT(refcount_count(&spa->spa_refcount) >= spa->spa_minref ||
662 	    MUTEX_HELD(&spa_namespace_lock));
663 	(void) refcount_add(&spa->spa_refcount, tag);
664 }
665 
666 /*
667  * Remove a reference to the given spa_t.  Must have at least one reference, or
668  * have the namespace lock held.
669  */
670 void
671 spa_close(spa_t *spa, void *tag)
672 {
673 	ASSERT(refcount_count(&spa->spa_refcount) > spa->spa_minref ||
674 	    MUTEX_HELD(&spa_namespace_lock));
675 	(void) refcount_remove(&spa->spa_refcount, tag);
676 }
677 
678 /*
679  * Check to see if the spa refcount is zero.  Must be called with
680  * spa_namespace_lock held.  We really compare against spa_minref, which is the
681  * number of references acquired when opening a pool
682  */
683 boolean_t
684 spa_refcount_zero(spa_t *spa)
685 {
686 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
687 
688 	return (refcount_count(&spa->spa_refcount) == spa->spa_minref);
689 }
690 
691 /*
692  * ==========================================================================
693  * SPA spare and l2cache tracking
694  * ==========================================================================
695  */
696 
697 /*
698  * Hot spares and cache devices are tracked using the same code below,
699  * for 'auxiliary' devices.
700  */
701 
702 typedef struct spa_aux {
703 	uint64_t	aux_guid;
704 	uint64_t	aux_pool;
705 	avl_node_t	aux_avl;
706 	int		aux_count;
707 } spa_aux_t;
708 
709 static int
710 spa_aux_compare(const void *a, const void *b)
711 {
712 	const spa_aux_t *sa = a;
713 	const spa_aux_t *sb = b;
714 
715 	if (sa->aux_guid < sb->aux_guid)
716 		return (-1);
717 	else if (sa->aux_guid > sb->aux_guid)
718 		return (1);
719 	else
720 		return (0);
721 }
722 
723 void
724 spa_aux_add(vdev_t *vd, avl_tree_t *avl)
725 {
726 	avl_index_t where;
727 	spa_aux_t search;
728 	spa_aux_t *aux;
729 
730 	search.aux_guid = vd->vdev_guid;
731 	if ((aux = avl_find(avl, &search, &where)) != NULL) {
732 		aux->aux_count++;
733 	} else {
734 		aux = kmem_zalloc(sizeof (spa_aux_t), KM_SLEEP);
735 		aux->aux_guid = vd->vdev_guid;
736 		aux->aux_count = 1;
737 		avl_insert(avl, aux, where);
738 	}
739 }
740 
741 void
742 spa_aux_remove(vdev_t *vd, avl_tree_t *avl)
743 {
744 	spa_aux_t search;
745 	spa_aux_t *aux;
746 	avl_index_t where;
747 
748 	search.aux_guid = vd->vdev_guid;
749 	aux = avl_find(avl, &search, &where);
750 
751 	ASSERT(aux != NULL);
752 
753 	if (--aux->aux_count == 0) {
754 		avl_remove(avl, aux);
755 		kmem_free(aux, sizeof (spa_aux_t));
756 	} else if (aux->aux_pool == spa_guid(vd->vdev_spa)) {
757 		aux->aux_pool = 0ULL;
758 	}
759 }
760 
761 boolean_t
762 spa_aux_exists(uint64_t guid, uint64_t *pool, int *refcnt, avl_tree_t *avl)
763 {
764 	spa_aux_t search, *found;
765 
766 	search.aux_guid = guid;
767 	found = avl_find(avl, &search, NULL);
768 
769 	if (pool) {
770 		if (found)
771 			*pool = found->aux_pool;
772 		else
773 			*pool = 0ULL;
774 	}
775 
776 	if (refcnt) {
777 		if (found)
778 			*refcnt = found->aux_count;
779 		else
780 			*refcnt = 0;
781 	}
782 
783 	return (found != NULL);
784 }
785 
786 void
787 spa_aux_activate(vdev_t *vd, avl_tree_t *avl)
788 {
789 	spa_aux_t search, *found;
790 	avl_index_t where;
791 
792 	search.aux_guid = vd->vdev_guid;
793 	found = avl_find(avl, &search, &where);
794 	ASSERT(found != NULL);
795 	ASSERT(found->aux_pool == 0ULL);
796 
797 	found->aux_pool = spa_guid(vd->vdev_spa);
798 }
799 
800 /*
801  * Spares are tracked globally due to the following constraints:
802  *
803  * 	- A spare may be part of multiple pools.
804  * 	- A spare may be added to a pool even if it's actively in use within
805  *	  another pool.
806  * 	- A spare in use in any pool can only be the source of a replacement if
807  *	  the target is a spare in the same pool.
808  *
809  * We keep track of all spares on the system through the use of a reference
810  * counted AVL tree.  When a vdev is added as a spare, or used as a replacement
811  * spare, then we bump the reference count in the AVL tree.  In addition, we set
812  * the 'vdev_isspare' member to indicate that the device is a spare (active or
813  * inactive).  When a spare is made active (used to replace a device in the
814  * pool), we also keep track of which pool its been made a part of.
815  *
816  * The 'spa_spare_lock' protects the AVL tree.  These functions are normally
817  * called under the spa_namespace lock as part of vdev reconfiguration.  The
818  * separate spare lock exists for the status query path, which does not need to
819  * be completely consistent with respect to other vdev configuration changes.
820  */
821 
822 static int
823 spa_spare_compare(const void *a, const void *b)
824 {
825 	return (spa_aux_compare(a, b));
826 }
827 
828 void
829 spa_spare_add(vdev_t *vd)
830 {
831 	mutex_enter(&spa_spare_lock);
832 	ASSERT(!vd->vdev_isspare);
833 	spa_aux_add(vd, &spa_spare_avl);
834 	vd->vdev_isspare = B_TRUE;
835 	mutex_exit(&spa_spare_lock);
836 }
837 
838 void
839 spa_spare_remove(vdev_t *vd)
840 {
841 	mutex_enter(&spa_spare_lock);
842 	ASSERT(vd->vdev_isspare);
843 	spa_aux_remove(vd, &spa_spare_avl);
844 	vd->vdev_isspare = B_FALSE;
845 	mutex_exit(&spa_spare_lock);
846 }
847 
848 boolean_t
849 spa_spare_exists(uint64_t guid, uint64_t *pool, int *refcnt)
850 {
851 	boolean_t found;
852 
853 	mutex_enter(&spa_spare_lock);
854 	found = spa_aux_exists(guid, pool, refcnt, &spa_spare_avl);
855 	mutex_exit(&spa_spare_lock);
856 
857 	return (found);
858 }
859 
860 void
861 spa_spare_activate(vdev_t *vd)
862 {
863 	mutex_enter(&spa_spare_lock);
864 	ASSERT(vd->vdev_isspare);
865 	spa_aux_activate(vd, &spa_spare_avl);
866 	mutex_exit(&spa_spare_lock);
867 }
868 
869 /*
870  * Level 2 ARC devices are tracked globally for the same reasons as spares.
871  * Cache devices currently only support one pool per cache device, and so
872  * for these devices the aux reference count is currently unused beyond 1.
873  */
874 
875 static int
876 spa_l2cache_compare(const void *a, const void *b)
877 {
878 	return (spa_aux_compare(a, b));
879 }
880 
881 void
882 spa_l2cache_add(vdev_t *vd)
883 {
884 	mutex_enter(&spa_l2cache_lock);
885 	ASSERT(!vd->vdev_isl2cache);
886 	spa_aux_add(vd, &spa_l2cache_avl);
887 	vd->vdev_isl2cache = B_TRUE;
888 	mutex_exit(&spa_l2cache_lock);
889 }
890 
891 void
892 spa_l2cache_remove(vdev_t *vd)
893 {
894 	mutex_enter(&spa_l2cache_lock);
895 	ASSERT(vd->vdev_isl2cache);
896 	spa_aux_remove(vd, &spa_l2cache_avl);
897 	vd->vdev_isl2cache = B_FALSE;
898 	mutex_exit(&spa_l2cache_lock);
899 }
900 
901 boolean_t
902 spa_l2cache_exists(uint64_t guid, uint64_t *pool)
903 {
904 	boolean_t found;
905 
906 	mutex_enter(&spa_l2cache_lock);
907 	found = spa_aux_exists(guid, pool, NULL, &spa_l2cache_avl);
908 	mutex_exit(&spa_l2cache_lock);
909 
910 	return (found);
911 }
912 
913 void
914 spa_l2cache_activate(vdev_t *vd)
915 {
916 	mutex_enter(&spa_l2cache_lock);
917 	ASSERT(vd->vdev_isl2cache);
918 	spa_aux_activate(vd, &spa_l2cache_avl);
919 	mutex_exit(&spa_l2cache_lock);
920 }
921 
922 /*
923  * ==========================================================================
924  * SPA vdev locking
925  * ==========================================================================
926  */
927 
928 /*
929  * Lock the given spa_t for the purpose of adding or removing a vdev.
930  * Grabs the global spa_namespace_lock plus the spa config lock for writing.
931  * It returns the next transaction group for the spa_t.
932  */
933 uint64_t
934 spa_vdev_enter(spa_t *spa)
935 {
936 	mutex_enter(&spa->spa_vdev_top_lock);
937 	mutex_enter(&spa_namespace_lock);
938 	return (spa_vdev_config_enter(spa));
939 }
940 
941 /*
942  * Internal implementation for spa_vdev_enter().  Used when a vdev
943  * operation requires multiple syncs (i.e. removing a device) while
944  * keeping the spa_namespace_lock held.
945  */
946 uint64_t
947 spa_vdev_config_enter(spa_t *spa)
948 {
949 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
950 
951 	spa_config_enter(spa, SCL_ALL, spa, RW_WRITER);
952 
953 	return (spa_last_synced_txg(spa) + 1);
954 }
955 
956 /*
957  * Used in combination with spa_vdev_config_enter() to allow the syncing
958  * of multiple transactions without releasing the spa_namespace_lock.
959  */
960 void
961 spa_vdev_config_exit(spa_t *spa, vdev_t *vd, uint64_t txg, int error, char *tag)
962 {
963 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
964 
965 	int config_changed = B_FALSE;
966 
967 	ASSERT(txg > spa_last_synced_txg(spa));
968 
969 	spa->spa_pending_vdev = NULL;
970 
971 	/*
972 	 * Reassess the DTLs.
973 	 */
974 	vdev_dtl_reassess(spa->spa_root_vdev, 0, 0, B_FALSE);
975 
976 	if (error == 0 && !list_is_empty(&spa->spa_config_dirty_list)) {
977 		config_changed = B_TRUE;
978 		spa->spa_config_generation++;
979 	}
980 
981 	/*
982 	 * Verify the metaslab classes.
983 	 */
984 	ASSERT(metaslab_class_validate(spa_normal_class(spa)) == 0);
985 	ASSERT(metaslab_class_validate(spa_log_class(spa)) == 0);
986 
987 	spa_config_exit(spa, SCL_ALL, spa);
988 
989 	/*
990 	 * Panic the system if the specified tag requires it.  This
991 	 * is useful for ensuring that configurations are updated
992 	 * transactionally.
993 	 */
994 	if (zio_injection_enabled)
995 		zio_handle_panic_injection(spa, tag, 0);
996 
997 	/*
998 	 * Note: this txg_wait_synced() is important because it ensures
999 	 * that there won't be more than one config change per txg.
1000 	 * This allows us to use the txg as the generation number.
1001 	 */
1002 	if (error == 0)
1003 		txg_wait_synced(spa->spa_dsl_pool, txg);
1004 
1005 	if (vd != NULL) {
1006 		ASSERT(!vd->vdev_detached || vd->vdev_dtl_smo.smo_object == 0);
1007 		spa_config_enter(spa, SCL_ALL, spa, RW_WRITER);
1008 		vdev_free(vd);
1009 		spa_config_exit(spa, SCL_ALL, spa);
1010 	}
1011 
1012 	/*
1013 	 * If the config changed, update the config cache.
1014 	 */
1015 	if (config_changed)
1016 		spa_config_sync(spa, B_FALSE, B_TRUE);
1017 }
1018 
1019 /*
1020  * Unlock the spa_t after adding or removing a vdev.  Besides undoing the
1021  * locking of spa_vdev_enter(), we also want make sure the transactions have
1022  * synced to disk, and then update the global configuration cache with the new
1023  * information.
1024  */
1025 int
1026 spa_vdev_exit(spa_t *spa, vdev_t *vd, uint64_t txg, int error)
1027 {
1028 	spa_vdev_config_exit(spa, vd, txg, error, FTAG);
1029 	mutex_exit(&spa_namespace_lock);
1030 	mutex_exit(&spa->spa_vdev_top_lock);
1031 
1032 	return (error);
1033 }
1034 
1035 /*
1036  * Lock the given spa_t for the purpose of changing vdev state.
1037  */
1038 void
1039 spa_vdev_state_enter(spa_t *spa, int oplocks)
1040 {
1041 	int locks = SCL_STATE_ALL | oplocks;
1042 
1043 	/*
1044 	 * Root pools may need to read of the underlying devfs filesystem
1045 	 * when opening up a vdev.  Unfortunately if we're holding the
1046 	 * SCL_ZIO lock it will result in a deadlock when we try to issue
1047 	 * the read from the root filesystem.  Instead we "prefetch"
1048 	 * the associated vnodes that we need prior to opening the
1049 	 * underlying devices and cache them so that we can prevent
1050 	 * any I/O when we are doing the actual open.
1051 	 */
1052 	if (spa_is_root(spa)) {
1053 		int low = locks & ~(SCL_ZIO - 1);
1054 		int high = locks & ~low;
1055 
1056 		spa_config_enter(spa, high, spa, RW_WRITER);
1057 		vdev_hold(spa->spa_root_vdev);
1058 		spa_config_enter(spa, low, spa, RW_WRITER);
1059 	} else {
1060 		spa_config_enter(spa, locks, spa, RW_WRITER);
1061 	}
1062 	spa->spa_vdev_locks = locks;
1063 }
1064 
1065 int
1066 spa_vdev_state_exit(spa_t *spa, vdev_t *vd, int error)
1067 {
1068 	boolean_t config_changed = B_FALSE;
1069 
1070 	if (vd != NULL || error == 0)
1071 		vdev_dtl_reassess(vd ? vd->vdev_top : spa->spa_root_vdev,
1072 		    0, 0, B_FALSE);
1073 
1074 	if (vd != NULL) {
1075 		vdev_state_dirty(vd->vdev_top);
1076 		config_changed = B_TRUE;
1077 		spa->spa_config_generation++;
1078 	}
1079 
1080 	if (spa_is_root(spa))
1081 		vdev_rele(spa->spa_root_vdev);
1082 
1083 	ASSERT3U(spa->spa_vdev_locks, >=, SCL_STATE_ALL);
1084 	spa_config_exit(spa, spa->spa_vdev_locks, spa);
1085 
1086 	/*
1087 	 * If anything changed, wait for it to sync.  This ensures that,
1088 	 * from the system administrator's perspective, zpool(1M) commands
1089 	 * are synchronous.  This is important for things like zpool offline:
1090 	 * when the command completes, you expect no further I/O from ZFS.
1091 	 */
1092 	if (vd != NULL)
1093 		txg_wait_synced(spa->spa_dsl_pool, 0);
1094 
1095 	/*
1096 	 * If the config changed, update the config cache.
1097 	 */
1098 	if (config_changed) {
1099 		mutex_enter(&spa_namespace_lock);
1100 		spa_config_sync(spa, B_FALSE, B_TRUE);
1101 		mutex_exit(&spa_namespace_lock);
1102 	}
1103 
1104 	return (error);
1105 }
1106 
1107 /*
1108  * ==========================================================================
1109  * Miscellaneous functions
1110  * ==========================================================================
1111  */
1112 
1113 void
1114 spa_activate_mos_feature(spa_t *spa, const char *feature)
1115 {
1116 	(void) nvlist_add_boolean(spa->spa_label_features, feature);
1117 	vdev_config_dirty(spa->spa_root_vdev);
1118 }
1119 
1120 void
1121 spa_deactivate_mos_feature(spa_t *spa, const char *feature)
1122 {
1123 	(void) nvlist_remove_all(spa->spa_label_features, feature);
1124 	vdev_config_dirty(spa->spa_root_vdev);
1125 }
1126 
1127 /*
1128  * Rename a spa_t.
1129  */
1130 int
1131 spa_rename(const char *name, const char *newname)
1132 {
1133 	spa_t *spa;
1134 	int err;
1135 
1136 	/*
1137 	 * Lookup the spa_t and grab the config lock for writing.  We need to
1138 	 * actually open the pool so that we can sync out the necessary labels.
1139 	 * It's OK to call spa_open() with the namespace lock held because we
1140 	 * allow recursive calls for other reasons.
1141 	 */
1142 	mutex_enter(&spa_namespace_lock);
1143 	if ((err = spa_open(name, &spa, FTAG)) != 0) {
1144 		mutex_exit(&spa_namespace_lock);
1145 		return (err);
1146 	}
1147 
1148 	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
1149 
1150 	avl_remove(&spa_namespace_avl, spa);
1151 	(void) strlcpy(spa->spa_name, newname, sizeof (spa->spa_name));
1152 	avl_add(&spa_namespace_avl, spa);
1153 
1154 	/*
1155 	 * Sync all labels to disk with the new names by marking the root vdev
1156 	 * dirty and waiting for it to sync.  It will pick up the new pool name
1157 	 * during the sync.
1158 	 */
1159 	vdev_config_dirty(spa->spa_root_vdev);
1160 
1161 	spa_config_exit(spa, SCL_ALL, FTAG);
1162 
1163 	txg_wait_synced(spa->spa_dsl_pool, 0);
1164 
1165 	/*
1166 	 * Sync the updated config cache.
1167 	 */
1168 	spa_config_sync(spa, B_FALSE, B_TRUE);
1169 
1170 	spa_close(spa, FTAG);
1171 
1172 	mutex_exit(&spa_namespace_lock);
1173 
1174 	return (0);
1175 }
1176 
1177 /*
1178  * Return the spa_t associated with given pool_guid, if it exists.  If
1179  * device_guid is non-zero, determine whether the pool exists *and* contains
1180  * a device with the specified device_guid.
1181  */
1182 spa_t *
1183 spa_by_guid(uint64_t pool_guid, uint64_t device_guid)
1184 {
1185 	spa_t *spa;
1186 	avl_tree_t *t = &spa_namespace_avl;
1187 
1188 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
1189 
1190 	for (spa = avl_first(t); spa != NULL; spa = AVL_NEXT(t, spa)) {
1191 		if (spa->spa_state == POOL_STATE_UNINITIALIZED)
1192 			continue;
1193 		if (spa->spa_root_vdev == NULL)
1194 			continue;
1195 		if (spa_guid(spa) == pool_guid) {
1196 			if (device_guid == 0)
1197 				break;
1198 
1199 			if (vdev_lookup_by_guid(spa->spa_root_vdev,
1200 			    device_guid) != NULL)
1201 				break;
1202 
1203 			/*
1204 			 * Check any devices we may be in the process of adding.
1205 			 */
1206 			if (spa->spa_pending_vdev) {
1207 				if (vdev_lookup_by_guid(spa->spa_pending_vdev,
1208 				    device_guid) != NULL)
1209 					break;
1210 			}
1211 		}
1212 	}
1213 
1214 	return (spa);
1215 }
1216 
1217 /*
1218  * Determine whether a pool with the given pool_guid exists.
1219  */
1220 boolean_t
1221 spa_guid_exists(uint64_t pool_guid, uint64_t device_guid)
1222 {
1223 	return (spa_by_guid(pool_guid, device_guid) != NULL);
1224 }
1225 
1226 char *
1227 spa_strdup(const char *s)
1228 {
1229 	size_t len;
1230 	char *new;
1231 
1232 	len = strlen(s);
1233 	new = kmem_alloc(len + 1, KM_SLEEP);
1234 	bcopy(s, new, len);
1235 	new[len] = '\0';
1236 
1237 	return (new);
1238 }
1239 
1240 void
1241 spa_strfree(char *s)
1242 {
1243 	kmem_free(s, strlen(s) + 1);
1244 }
1245 
1246 uint64_t
1247 spa_get_random(uint64_t range)
1248 {
1249 	uint64_t r;
1250 
1251 	ASSERT(range != 0);
1252 
1253 	(void) random_get_pseudo_bytes((void *)&r, sizeof (uint64_t));
1254 
1255 	return (r % range);
1256 }
1257 
1258 uint64_t
1259 spa_generate_guid(spa_t *spa)
1260 {
1261 	uint64_t guid = spa_get_random(-1ULL);
1262 
1263 	if (spa != NULL) {
1264 		while (guid == 0 || spa_guid_exists(spa_guid(spa), guid))
1265 			guid = spa_get_random(-1ULL);
1266 	} else {
1267 		while (guid == 0 || spa_guid_exists(guid, 0))
1268 			guid = spa_get_random(-1ULL);
1269 	}
1270 
1271 	return (guid);
1272 }
1273 
1274 void
1275 sprintf_blkptr(char *buf, const blkptr_t *bp)
1276 {
1277 	char type[256];
1278 	char *checksum = NULL;
1279 	char *compress = NULL;
1280 
1281 	if (bp != NULL) {
1282 		if (BP_GET_TYPE(bp) & DMU_OT_NEWTYPE) {
1283 			dmu_object_byteswap_t bswap =
1284 			    DMU_OT_BYTESWAP(BP_GET_TYPE(bp));
1285 			(void) snprintf(type, sizeof (type), "bswap %s %s",
1286 			    DMU_OT_IS_METADATA(BP_GET_TYPE(bp)) ?
1287 			    "metadata" : "data",
1288 			    dmu_ot_byteswap[bswap].ob_name);
1289 		} else {
1290 			(void) strlcpy(type, dmu_ot[BP_GET_TYPE(bp)].ot_name,
1291 			    sizeof (type));
1292 		}
1293 		checksum = zio_checksum_table[BP_GET_CHECKSUM(bp)].ci_name;
1294 		compress = zio_compress_table[BP_GET_COMPRESS(bp)].ci_name;
1295 	}
1296 
1297 	SPRINTF_BLKPTR(snprintf, ' ', buf, bp, type, checksum, compress);
1298 }
1299 
1300 void
1301 spa_freeze(spa_t *spa)
1302 {
1303 	uint64_t freeze_txg = 0;
1304 
1305 	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
1306 	if (spa->spa_freeze_txg == UINT64_MAX) {
1307 		freeze_txg = spa_last_synced_txg(spa) + TXG_SIZE;
1308 		spa->spa_freeze_txg = freeze_txg;
1309 	}
1310 	spa_config_exit(spa, SCL_ALL, FTAG);
1311 	if (freeze_txg != 0)
1312 		txg_wait_synced(spa_get_dsl(spa), freeze_txg);
1313 }
1314 
1315 void
1316 zfs_panic_recover(const char *fmt, ...)
1317 {
1318 	va_list adx;
1319 
1320 	va_start(adx, fmt);
1321 	vcmn_err(zfs_recover ? CE_WARN : CE_PANIC, fmt, adx);
1322 	va_end(adx);
1323 }
1324 
1325 /*
1326  * This is a stripped-down version of strtoull, suitable only for converting
1327  * lowercase hexidecimal numbers that don't overflow.
1328  */
1329 uint64_t
1330 strtonum(const char *str, char **nptr)
1331 {
1332 	uint64_t val = 0;
1333 	char c;
1334 	int digit;
1335 
1336 	while ((c = *str) != '\0') {
1337 		if (c >= '0' && c <= '9')
1338 			digit = c - '0';
1339 		else if (c >= 'a' && c <= 'f')
1340 			digit = 10 + c - 'a';
1341 		else
1342 			break;
1343 
1344 		val *= 16;
1345 		val += digit;
1346 
1347 		str++;
1348 	}
1349 
1350 	if (nptr)
1351 		*nptr = (char *)str;
1352 
1353 	return (val);
1354 }
1355 
1356 /*
1357  * ==========================================================================
1358  * Accessor functions
1359  * ==========================================================================
1360  */
1361 
1362 boolean_t
1363 spa_shutting_down(spa_t *spa)
1364 {
1365 	return (spa->spa_async_suspended);
1366 }
1367 
1368 dsl_pool_t *
1369 spa_get_dsl(spa_t *spa)
1370 {
1371 	return (spa->spa_dsl_pool);
1372 }
1373 
1374 boolean_t
1375 spa_is_initializing(spa_t *spa)
1376 {
1377 	return (spa->spa_is_initializing);
1378 }
1379 
1380 blkptr_t *
1381 spa_get_rootblkptr(spa_t *spa)
1382 {
1383 	return (&spa->spa_ubsync.ub_rootbp);
1384 }
1385 
1386 void
1387 spa_set_rootblkptr(spa_t *spa, const blkptr_t *bp)
1388 {
1389 	spa->spa_uberblock.ub_rootbp = *bp;
1390 }
1391 
1392 void
1393 spa_altroot(spa_t *spa, char *buf, size_t buflen)
1394 {
1395 	if (spa->spa_root == NULL)
1396 		buf[0] = '\0';
1397 	else
1398 		(void) strncpy(buf, spa->spa_root, buflen);
1399 }
1400 
1401 int
1402 spa_sync_pass(spa_t *spa)
1403 {
1404 	return (spa->spa_sync_pass);
1405 }
1406 
1407 char *
1408 spa_name(spa_t *spa)
1409 {
1410 	return (spa->spa_name);
1411 }
1412 
1413 uint64_t
1414 spa_guid(spa_t *spa)
1415 {
1416 	dsl_pool_t *dp = spa_get_dsl(spa);
1417 	uint64_t guid;
1418 
1419 	/*
1420 	 * If we fail to parse the config during spa_load(), we can go through
1421 	 * the error path (which posts an ereport) and end up here with no root
1422 	 * vdev.  We stash the original pool guid in 'spa_config_guid' to handle
1423 	 * this case.
1424 	 */
1425 	if (spa->spa_root_vdev == NULL)
1426 		return (spa->spa_config_guid);
1427 
1428 	guid = spa->spa_last_synced_guid != 0 ?
1429 	    spa->spa_last_synced_guid : spa->spa_root_vdev->vdev_guid;
1430 
1431 	/*
1432 	 * Return the most recently synced out guid unless we're
1433 	 * in syncing context.
1434 	 */
1435 	if (dp && dsl_pool_sync_context(dp))
1436 		return (spa->spa_root_vdev->vdev_guid);
1437 	else
1438 		return (guid);
1439 }
1440 
1441 uint64_t
1442 spa_load_guid(spa_t *spa)
1443 {
1444 	/*
1445 	 * This is a GUID that exists solely as a reference for the
1446 	 * purposes of the arc.  It is generated at load time, and
1447 	 * is never written to persistent storage.
1448 	 */
1449 	return (spa->spa_load_guid);
1450 }
1451 
1452 uint64_t
1453 spa_last_synced_txg(spa_t *spa)
1454 {
1455 	return (spa->spa_ubsync.ub_txg);
1456 }
1457 
1458 uint64_t
1459 spa_first_txg(spa_t *spa)
1460 {
1461 	return (spa->spa_first_txg);
1462 }
1463 
1464 uint64_t
1465 spa_syncing_txg(spa_t *spa)
1466 {
1467 	return (spa->spa_syncing_txg);
1468 }
1469 
1470 pool_state_t
1471 spa_state(spa_t *spa)
1472 {
1473 	return (spa->spa_state);
1474 }
1475 
1476 spa_load_state_t
1477 spa_load_state(spa_t *spa)
1478 {
1479 	return (spa->spa_load_state);
1480 }
1481 
1482 uint64_t
1483 spa_freeze_txg(spa_t *spa)
1484 {
1485 	return (spa->spa_freeze_txg);
1486 }
1487 
1488 /* ARGSUSED */
1489 uint64_t
1490 spa_get_asize(spa_t *spa, uint64_t lsize)
1491 {
1492 	/*
1493 	 * The worst case is single-sector max-parity RAID-Z blocks, in which
1494 	 * case the space requirement is exactly (VDEV_RAIDZ_MAXPARITY + 1)
1495 	 * times the size; so just assume that.  Add to this the fact that
1496 	 * we can have up to 3 DVAs per bp, and one more factor of 2 because
1497 	 * the block may be dittoed with up to 3 DVAs by ddt_sync().
1498 	 */
1499 	return (lsize * (VDEV_RAIDZ_MAXPARITY + 1) * SPA_DVAS_PER_BP * 2);
1500 }
1501 
1502 uint64_t
1503 spa_get_dspace(spa_t *spa)
1504 {
1505 	return (spa->spa_dspace);
1506 }
1507 
1508 void
1509 spa_update_dspace(spa_t *spa)
1510 {
1511 	spa->spa_dspace = metaslab_class_get_dspace(spa_normal_class(spa)) +
1512 	    ddt_get_dedup_dspace(spa);
1513 }
1514 
1515 /*
1516  * Return the failure mode that has been set to this pool. The default
1517  * behavior will be to block all I/Os when a complete failure occurs.
1518  */
1519 uint8_t
1520 spa_get_failmode(spa_t *spa)
1521 {
1522 	return (spa->spa_failmode);
1523 }
1524 
1525 boolean_t
1526 spa_suspended(spa_t *spa)
1527 {
1528 	return (spa->spa_suspended);
1529 }
1530 
1531 uint64_t
1532 spa_version(spa_t *spa)
1533 {
1534 	return (spa->spa_ubsync.ub_version);
1535 }
1536 
1537 boolean_t
1538 spa_deflate(spa_t *spa)
1539 {
1540 	return (spa->spa_deflate);
1541 }
1542 
1543 metaslab_class_t *
1544 spa_normal_class(spa_t *spa)
1545 {
1546 	return (spa->spa_normal_class);
1547 }
1548 
1549 metaslab_class_t *
1550 spa_log_class(spa_t *spa)
1551 {
1552 	return (spa->spa_log_class);
1553 }
1554 
1555 int
1556 spa_max_replication(spa_t *spa)
1557 {
1558 	/*
1559 	 * As of SPA_VERSION == SPA_VERSION_DITTO_BLOCKS, we are able to
1560 	 * handle BPs with more than one DVA allocated.  Set our max
1561 	 * replication level accordingly.
1562 	 */
1563 	if (spa_version(spa) < SPA_VERSION_DITTO_BLOCKS)
1564 		return (1);
1565 	return (MIN(SPA_DVAS_PER_BP, spa_max_replication_override));
1566 }
1567 
1568 int
1569 spa_prev_software_version(spa_t *spa)
1570 {
1571 	return (spa->spa_prev_software_version);
1572 }
1573 
1574 uint64_t
1575 spa_deadman_synctime(spa_t *spa)
1576 {
1577 	return (spa->spa_deadman_synctime);
1578 }
1579 
1580 uint64_t
1581 dva_get_dsize_sync(spa_t *spa, const dva_t *dva)
1582 {
1583 	uint64_t asize = DVA_GET_ASIZE(dva);
1584 	uint64_t dsize = asize;
1585 
1586 	ASSERT(spa_config_held(spa, SCL_ALL, RW_READER) != 0);
1587 
1588 	if (asize != 0 && spa->spa_deflate) {
1589 		vdev_t *vd = vdev_lookup_top(spa, DVA_GET_VDEV(dva));
1590 		dsize = (asize >> SPA_MINBLOCKSHIFT) * vd->vdev_deflate_ratio;
1591 	}
1592 
1593 	return (dsize);
1594 }
1595 
1596 uint64_t
1597 bp_get_dsize_sync(spa_t *spa, const blkptr_t *bp)
1598 {
1599 	uint64_t dsize = 0;
1600 
1601 	for (int d = 0; d < SPA_DVAS_PER_BP; d++)
1602 		dsize += dva_get_dsize_sync(spa, &bp->blk_dva[d]);
1603 
1604 	return (dsize);
1605 }
1606 
1607 uint64_t
1608 bp_get_dsize(spa_t *spa, const blkptr_t *bp)
1609 {
1610 	uint64_t dsize = 0;
1611 
1612 	spa_config_enter(spa, SCL_VDEV, FTAG, RW_READER);
1613 
1614 	for (int d = 0; d < SPA_DVAS_PER_BP; d++)
1615 		dsize += dva_get_dsize_sync(spa, &bp->blk_dva[d]);
1616 
1617 	spa_config_exit(spa, SCL_VDEV, FTAG);
1618 
1619 	return (dsize);
1620 }
1621 
1622 /*
1623  * ==========================================================================
1624  * Initialization and Termination
1625  * ==========================================================================
1626  */
1627 
1628 static int
1629 spa_name_compare(const void *a1, const void *a2)
1630 {
1631 	const spa_t *s1 = a1;
1632 	const spa_t *s2 = a2;
1633 	int s;
1634 
1635 	s = strcmp(s1->spa_name, s2->spa_name);
1636 	if (s > 0)
1637 		return (1);
1638 	if (s < 0)
1639 		return (-1);
1640 	return (0);
1641 }
1642 
1643 int
1644 spa_busy(void)
1645 {
1646 	return (spa_active_count);
1647 }
1648 
1649 void
1650 spa_boot_init()
1651 {
1652 	spa_config_load();
1653 }
1654 
1655 void
1656 spa_init(int mode)
1657 {
1658 	mutex_init(&spa_namespace_lock, NULL, MUTEX_DEFAULT, NULL);
1659 	mutex_init(&spa_spare_lock, NULL, MUTEX_DEFAULT, NULL);
1660 	mutex_init(&spa_l2cache_lock, NULL, MUTEX_DEFAULT, NULL);
1661 	cv_init(&spa_namespace_cv, NULL, CV_DEFAULT, NULL);
1662 
1663 	avl_create(&spa_namespace_avl, spa_name_compare, sizeof (spa_t),
1664 	    offsetof(spa_t, spa_avl));
1665 
1666 	avl_create(&spa_spare_avl, spa_spare_compare, sizeof (spa_aux_t),
1667 	    offsetof(spa_aux_t, aux_avl));
1668 
1669 	avl_create(&spa_l2cache_avl, spa_l2cache_compare, sizeof (spa_aux_t),
1670 	    offsetof(spa_aux_t, aux_avl));
1671 
1672 	spa_mode_global = mode;
1673 
1674 #ifdef _KERNEL
1675 	spa_arch_init();
1676 #else
1677 	if (spa_mode_global != FREAD && dprintf_find_string("watch")) {
1678 		arc_procfd = open("/proc/self/ctl", O_WRONLY);
1679 		if (arc_procfd == -1) {
1680 			perror("could not enable watchpoints: "
1681 			    "opening /proc/self/ctl failed: ");
1682 		} else {
1683 			arc_watch = B_TRUE;
1684 		}
1685 	}
1686 #endif
1687 
1688 	refcount_init();
1689 	unique_init();
1690 	zio_init();
1691 	dmu_init();
1692 	zil_init();
1693 	vdev_cache_stat_init();
1694 	zfs_prop_init();
1695 	zpool_prop_init();
1696 	zpool_feature_init();
1697 	spa_config_load();
1698 	l2arc_start();
1699 }
1700 
1701 void
1702 spa_fini(void)
1703 {
1704 	l2arc_stop();
1705 
1706 	spa_evict_all();
1707 
1708 	vdev_cache_stat_fini();
1709 	zil_fini();
1710 	dmu_fini();
1711 	zio_fini();
1712 	unique_fini();
1713 	refcount_fini();
1714 
1715 	avl_destroy(&spa_namespace_avl);
1716 	avl_destroy(&spa_spare_avl);
1717 	avl_destroy(&spa_l2cache_avl);
1718 
1719 	cv_destroy(&spa_namespace_cv);
1720 	mutex_destroy(&spa_namespace_lock);
1721 	mutex_destroy(&spa_spare_lock);
1722 	mutex_destroy(&spa_l2cache_lock);
1723 }
1724 
1725 /*
1726  * Return whether this pool has slogs. No locking needed.
1727  * It's not a problem if the wrong answer is returned as it's only for
1728  * performance and not correctness
1729  */
1730 boolean_t
1731 spa_has_slogs(spa_t *spa)
1732 {
1733 	return (spa->spa_log_class->mc_rotor != NULL);
1734 }
1735 
1736 spa_log_state_t
1737 spa_get_log_state(spa_t *spa)
1738 {
1739 	return (spa->spa_log_state);
1740 }
1741 
1742 void
1743 spa_set_log_state(spa_t *spa, spa_log_state_t state)
1744 {
1745 	spa->spa_log_state = state;
1746 }
1747 
1748 boolean_t
1749 spa_is_root(spa_t *spa)
1750 {
1751 	return (spa->spa_is_root);
1752 }
1753 
1754 boolean_t
1755 spa_writeable(spa_t *spa)
1756 {
1757 	return (!!(spa->spa_mode & FWRITE));
1758 }
1759 
1760 int
1761 spa_mode(spa_t *spa)
1762 {
1763 	return (spa->spa_mode);
1764 }
1765 
1766 uint64_t
1767 spa_bootfs(spa_t *spa)
1768 {
1769 	return (spa->spa_bootfs);
1770 }
1771 
1772 uint64_t
1773 spa_delegation(spa_t *spa)
1774 {
1775 	return (spa->spa_delegation);
1776 }
1777 
1778 objset_t *
1779 spa_meta_objset(spa_t *spa)
1780 {
1781 	return (spa->spa_meta_objset);
1782 }
1783 
1784 enum zio_checksum
1785 spa_dedup_checksum(spa_t *spa)
1786 {
1787 	return (spa->spa_dedup_checksum);
1788 }
1789 
1790 /*
1791  * Reset pool scan stat per scan pass (or reboot).
1792  */
1793 void
1794 spa_scan_stat_init(spa_t *spa)
1795 {
1796 	/* data not stored on disk */
1797 	spa->spa_scan_pass_start = gethrestime_sec();
1798 	spa->spa_scan_pass_exam = 0;
1799 	vdev_scan_stat_init(spa->spa_root_vdev);
1800 }
1801 
1802 /*
1803  * Get scan stats for zpool status reports
1804  */
1805 int
1806 spa_scan_get_stats(spa_t *spa, pool_scan_stat_t *ps)
1807 {
1808 	dsl_scan_t *scn = spa->spa_dsl_pool ? spa->spa_dsl_pool->dp_scan : NULL;
1809 
1810 	if (scn == NULL || scn->scn_phys.scn_func == POOL_SCAN_NONE)
1811 		return (ENOENT);
1812 	bzero(ps, sizeof (pool_scan_stat_t));
1813 
1814 	/* data stored on disk */
1815 	ps->pss_func = scn->scn_phys.scn_func;
1816 	ps->pss_start_time = scn->scn_phys.scn_start_time;
1817 	ps->pss_end_time = scn->scn_phys.scn_end_time;
1818 	ps->pss_to_examine = scn->scn_phys.scn_to_examine;
1819 	ps->pss_examined = scn->scn_phys.scn_examined;
1820 	ps->pss_to_process = scn->scn_phys.scn_to_process;
1821 	ps->pss_processed = scn->scn_phys.scn_processed;
1822 	ps->pss_errors = scn->scn_phys.scn_errors;
1823 	ps->pss_state = scn->scn_phys.scn_state;
1824 
1825 	/* data not stored on disk */
1826 	ps->pss_pass_start = spa->spa_scan_pass_start;
1827 	ps->pss_pass_exam = spa->spa_scan_pass_exam;
1828 
1829 	return (0);
1830 }
1831 
1832 boolean_t
1833 spa_debug_enabled(spa_t *spa)
1834 {
1835 	return (spa->spa_debug);
1836 }
1837