spa_misc.c revision 681d9761e8516a7dc5ab6589e2dfe717777e1123
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 2009 Sun Microsystems, Inc.  All rights reserved.
23 * Use is subject to license terms.
24 */
25
26#include <sys/zfs_context.h>
27#include <sys/spa_impl.h>
28#include <sys/zio.h>
29#include <sys/zio_checksum.h>
30#include <sys/zio_compress.h>
31#include <sys/dmu.h>
32#include <sys/dmu_tx.h>
33#include <sys/zap.h>
34#include <sys/zil.h>
35#include <sys/vdev_impl.h>
36#include <sys/metaslab.h>
37#include <sys/uberblock_impl.h>
38#include <sys/txg.h>
39#include <sys/avl.h>
40#include <sys/unique.h>
41#include <sys/dsl_pool.h>
42#include <sys/dsl_dir.h>
43#include <sys/dsl_prop.h>
44#include <sys/fs/zfs.h>
45#include <sys/metaslab_impl.h>
46#include <sys/sunddi.h>
47#include <sys/arc.h>
48#include "zfs_prop.h"
49
50/*
51 * SPA locking
52 *
53 * There are four basic locks for managing spa_t structures:
54 *
55 * spa_namespace_lock (global mutex)
56 *
57 *	This lock must be acquired to do any of the following:
58 *
59 *		- Lookup a spa_t by name
60 *		- Add or remove a spa_t from the namespace
61 *		- Increase spa_refcount from non-zero
62 *		- Check if spa_refcount is zero
63 *		- Rename a spa_t
64 *		- add/remove/attach/detach devices
65 *		- Held for the duration of create/destroy/import/export
66 *
67 *	It does not need to handle recursion.  A create or destroy may
68 *	reference objects (files or zvols) in other pools, but by
69 *	definition they must have an existing reference, and will never need
70 *	to lookup a spa_t by name.
71 *
72 * spa_refcount (per-spa refcount_t protected by mutex)
73 *
74 *	This reference count keep track of any active users of the spa_t.  The
75 *	spa_t cannot be destroyed or freed while this is non-zero.  Internally,
76 *	the refcount is never really 'zero' - opening a pool implicitly keeps
77 *	some references in the DMU.  Internally we check against spa_minref, but
78 *	present the image of a zero/non-zero value to consumers.
79 *
80 * spa_config_lock[] (per-spa array of rwlocks)
81 *
82 *	This protects the spa_t from config changes, and must be held in
83 *	the following circumstances:
84 *
85 *		- RW_READER to perform I/O to the spa
86 *		- RW_WRITER to change the vdev config
87 *
88 * The locking order is fairly straightforward:
89 *
90 *		spa_namespace_lock	->	spa_refcount
91 *
92 *	The namespace lock must be acquired to increase the refcount from 0
93 *	or to check if it is zero.
94 *
95 *		spa_refcount		->	spa_config_lock[]
96 *
97 *	There must be at least one valid reference on the spa_t to acquire
98 *	the config lock.
99 *
100 *		spa_namespace_lock	->	spa_config_lock[]
101 *
102 *	The namespace lock must always be taken before the config lock.
103 *
104 *
105 * The spa_namespace_lock can be acquired directly and is globally visible.
106 *
107 * The namespace is manipulated using the following functions, all of which
108 * require the spa_namespace_lock to be held.
109 *
110 *	spa_lookup()		Lookup a spa_t by name.
111 *
112 *	spa_add()		Create a new spa_t in the namespace.
113 *
114 *	spa_remove()		Remove a spa_t from the namespace.  This also
115 *				frees up any memory associated with the spa_t.
116 *
117 *	spa_next()		Returns the next spa_t in the system, or the
118 *				first if NULL is passed.
119 *
120 *	spa_evict_all()		Shutdown and remove all spa_t structures in
121 *				the system.
122 *
123 *	spa_guid_exists()	Determine whether a pool/device guid exists.
124 *
125 * The spa_refcount is manipulated using the following functions:
126 *
127 *	spa_open_ref()		Adds a reference to the given spa_t.  Must be
128 *				called with spa_namespace_lock held if the
129 *				refcount is currently zero.
130 *
131 *	spa_close()		Remove a reference from the spa_t.  This will
132 *				not free the spa_t or remove it from the
133 *				namespace.  No locking is required.
134 *
135 *	spa_refcount_zero()	Returns true if the refcount is currently
136 *				zero.  Must be called with spa_namespace_lock
137 *				held.
138 *
139 * The spa_config_lock[] is an array of rwlocks, ordered as follows:
140 * SCL_CONFIG > SCL_STATE > SCL_ALLOC > SCL_ZIO > SCL_FREE > SCL_VDEV.
141 * spa_config_lock[] is manipulated with spa_config_{enter,exit,held}().
142 *
143 * To read the configuration, it suffices to hold one of these locks as reader.
144 * To modify the configuration, you must hold all locks as writer.  To modify
145 * vdev state without altering the vdev tree's topology (e.g. online/offline),
146 * you must hold SCL_STATE and SCL_ZIO as writer.
147 *
148 * We use these distinct config locks to avoid recursive lock entry.
149 * For example, spa_sync() (which holds SCL_CONFIG as reader) induces
150 * block allocations (SCL_ALLOC), which may require reading space maps
151 * from disk (dmu_read() -> zio_read() -> SCL_ZIO).
152 *
153 * The spa config locks cannot be normal rwlocks because we need the
154 * ability to hand off ownership.  For example, SCL_ZIO is acquired
155 * by the issuing thread and later released by an interrupt thread.
156 * They do, however, obey the usual write-wanted semantics to prevent
157 * writer (i.e. system administrator) starvation.
158 *
159 * The lock acquisition rules are as follows:
160 *
161 * SCL_CONFIG
162 *	Protects changes to the vdev tree topology, such as vdev
163 *	add/remove/attach/detach.  Protects the dirty config list
164 *	(spa_config_dirty_list) and the set of spares and l2arc devices.
165 *
166 * SCL_STATE
167 *	Protects changes to pool state and vdev state, such as vdev
168 *	online/offline/fault/degrade/clear.  Protects the dirty state list
169 *	(spa_state_dirty_list) and global pool state (spa_state).
170 *
171 * SCL_ALLOC
172 *	Protects changes to metaslab groups and classes.
173 *	Held as reader by metaslab_alloc() and metaslab_claim().
174 *
175 * SCL_ZIO
176 *	Held by bp-level zios (those which have no io_vd upon entry)
177 *	to prevent changes to the vdev tree.  The bp-level zio implicitly
178 *	protects all of its vdev child zios, which do not hold SCL_ZIO.
179 *
180 * SCL_FREE
181 *	Protects changes to metaslab groups and classes.
182 *	Held as reader by metaslab_free().  SCL_FREE is distinct from
183 *	SCL_ALLOC, and lower than SCL_ZIO, so that we can safely free
184 *	blocks in zio_done() while another i/o that holds either
185 *	SCL_ALLOC or SCL_ZIO is waiting for this i/o to complete.
186 *
187 * SCL_VDEV
188 *	Held as reader to prevent changes to the vdev tree during trivial
189 *	inquiries such as bp_get_dasize().  SCL_VDEV is distinct from the
190 *	other locks, and lower than all of them, to ensure that it's safe
191 *	to acquire regardless of caller context.
192 *
193 * In addition, the following rules apply:
194 *
195 * (a)	spa_props_lock protects pool properties, spa_config and spa_config_list.
196 *	The lock ordering is SCL_CONFIG > spa_props_lock.
197 *
198 * (b)	I/O operations on leaf vdevs.  For any zio operation that takes
199 *	an explicit vdev_t argument -- such as zio_ioctl(), zio_read_phys(),
200 *	or zio_write_phys() -- the caller must ensure that the config cannot
201 *	cannot change in the interim, and that the vdev cannot be reopened.
202 *	SCL_STATE as reader suffices for both.
203 *
204 * The vdev configuration is protected by spa_vdev_enter() / spa_vdev_exit().
205 *
206 *	spa_vdev_enter()	Acquire the namespace lock and the config lock
207 *				for writing.
208 *
209 *	spa_vdev_exit()		Release the config lock, wait for all I/O
210 *				to complete, sync the updated configs to the
211 *				cache, and release the namespace lock.
212 *
213 * vdev state is protected by spa_vdev_state_enter() / spa_vdev_state_exit().
214 * Like spa_vdev_enter/exit, these are convenience wrappers -- the actual
215 * locking is, always, based on spa_namespace_lock and spa_config_lock[].
216 *
217 * spa_rename() is also implemented within this file since is requires
218 * manipulation of the namespace.
219 */
220
221static avl_tree_t spa_namespace_avl;
222kmutex_t spa_namespace_lock;
223static kcondvar_t spa_namespace_cv;
224static int spa_active_count;
225int spa_max_replication_override = SPA_DVAS_PER_BP;
226
227static kmutex_t spa_spare_lock;
228static avl_tree_t spa_spare_avl;
229static kmutex_t spa_l2cache_lock;
230static avl_tree_t spa_l2cache_avl;
231
232kmem_cache_t *spa_buffer_pool;
233int spa_mode_global;
234
235#ifdef ZFS_DEBUG
236/* Everything except dprintf is on by default in debug builds */
237int zfs_flags = ~ZFS_DEBUG_DPRINTF;
238#else
239int zfs_flags = 0;
240#endif
241
242/*
243 * zfs_recover can be set to nonzero to attempt to recover from
244 * otherwise-fatal errors, typically caused by on-disk corruption.  When
245 * set, calls to zfs_panic_recover() will turn into warning messages.
246 */
247int zfs_recover = 0;
248
249
250/*
251 * ==========================================================================
252 * SPA config locking
253 * ==========================================================================
254 */
255static void
256spa_config_lock_init(spa_t *spa)
257{
258	for (int i = 0; i < SCL_LOCKS; i++) {
259		spa_config_lock_t *scl = &spa->spa_config_lock[i];
260		mutex_init(&scl->scl_lock, NULL, MUTEX_DEFAULT, NULL);
261		cv_init(&scl->scl_cv, NULL, CV_DEFAULT, NULL);
262		refcount_create(&scl->scl_count);
263		scl->scl_writer = NULL;
264		scl->scl_write_wanted = 0;
265	}
266}
267
268static void
269spa_config_lock_destroy(spa_t *spa)
270{
271	for (int i = 0; i < SCL_LOCKS; i++) {
272		spa_config_lock_t *scl = &spa->spa_config_lock[i];
273		mutex_destroy(&scl->scl_lock);
274		cv_destroy(&scl->scl_cv);
275		refcount_destroy(&scl->scl_count);
276		ASSERT(scl->scl_writer == NULL);
277		ASSERT(scl->scl_write_wanted == 0);
278	}
279}
280
281int
282spa_config_tryenter(spa_t *spa, int locks, void *tag, krw_t rw)
283{
284	for (int i = 0; i < SCL_LOCKS; i++) {
285		spa_config_lock_t *scl = &spa->spa_config_lock[i];
286		if (!(locks & (1 << i)))
287			continue;
288		mutex_enter(&scl->scl_lock);
289		if (rw == RW_READER) {
290			if (scl->scl_writer || scl->scl_write_wanted) {
291				mutex_exit(&scl->scl_lock);
292				spa_config_exit(spa, locks ^ (1 << i), tag);
293				return (0);
294			}
295		} else {
296			ASSERT(scl->scl_writer != curthread);
297			if (!refcount_is_zero(&scl->scl_count)) {
298				mutex_exit(&scl->scl_lock);
299				spa_config_exit(spa, locks ^ (1 << i), tag);
300				return (0);
301			}
302			scl->scl_writer = curthread;
303		}
304		(void) refcount_add(&scl->scl_count, tag);
305		mutex_exit(&scl->scl_lock);
306	}
307	return (1);
308}
309
310void
311spa_config_enter(spa_t *spa, int locks, void *tag, krw_t rw)
312{
313	int wlocks_held = 0;
314
315	for (int i = 0; i < SCL_LOCKS; i++) {
316		spa_config_lock_t *scl = &spa->spa_config_lock[i];
317		if (scl->scl_writer == curthread)
318			wlocks_held |= (1 << i);
319		if (!(locks & (1 << i)))
320			continue;
321		mutex_enter(&scl->scl_lock);
322		if (rw == RW_READER) {
323			while (scl->scl_writer || scl->scl_write_wanted) {
324				cv_wait(&scl->scl_cv, &scl->scl_lock);
325			}
326		} else {
327			ASSERT(scl->scl_writer != curthread);
328			while (!refcount_is_zero(&scl->scl_count)) {
329				scl->scl_write_wanted++;
330				cv_wait(&scl->scl_cv, &scl->scl_lock);
331				scl->scl_write_wanted--;
332			}
333			scl->scl_writer = curthread;
334		}
335		(void) refcount_add(&scl->scl_count, tag);
336		mutex_exit(&scl->scl_lock);
337	}
338	ASSERT(wlocks_held <= locks);
339}
340
341void
342spa_config_exit(spa_t *spa, int locks, void *tag)
343{
344	for (int i = SCL_LOCKS - 1; i >= 0; i--) {
345		spa_config_lock_t *scl = &spa->spa_config_lock[i];
346		if (!(locks & (1 << i)))
347			continue;
348		mutex_enter(&scl->scl_lock);
349		ASSERT(!refcount_is_zero(&scl->scl_count));
350		if (refcount_remove(&scl->scl_count, tag) == 0) {
351			ASSERT(scl->scl_writer == NULL ||
352			    scl->scl_writer == curthread);
353			scl->scl_writer = NULL;	/* OK in either case */
354			cv_broadcast(&scl->scl_cv);
355		}
356		mutex_exit(&scl->scl_lock);
357	}
358}
359
360int
361spa_config_held(spa_t *spa, int locks, krw_t rw)
362{
363	int locks_held = 0;
364
365	for (int i = 0; i < SCL_LOCKS; i++) {
366		spa_config_lock_t *scl = &spa->spa_config_lock[i];
367		if (!(locks & (1 << i)))
368			continue;
369		if ((rw == RW_READER && !refcount_is_zero(&scl->scl_count)) ||
370		    (rw == RW_WRITER && scl->scl_writer == curthread))
371			locks_held |= 1 << i;
372	}
373
374	return (locks_held);
375}
376
377/*
378 * ==========================================================================
379 * SPA namespace functions
380 * ==========================================================================
381 */
382
383/*
384 * Lookup the named spa_t in the AVL tree.  The spa_namespace_lock must be held.
385 * Returns NULL if no matching spa_t is found.
386 */
387spa_t *
388spa_lookup(const char *name)
389{
390	static spa_t search;	/* spa_t is large; don't allocate on stack */
391	spa_t *spa;
392	avl_index_t where;
393	char c;
394	char *cp;
395
396	ASSERT(MUTEX_HELD(&spa_namespace_lock));
397
398	/*
399	 * If it's a full dataset name, figure out the pool name and
400	 * just use that.
401	 */
402	cp = strpbrk(name, "/@");
403	if (cp) {
404		c = *cp;
405		*cp = '\0';
406	}
407
408	(void) strlcpy(search.spa_name, name, sizeof (search.spa_name));
409	spa = avl_find(&spa_namespace_avl, &search, &where);
410
411	if (cp)
412		*cp = c;
413
414	return (spa);
415}
416
417/*
418 * Create an uninitialized spa_t with the given name.  Requires
419 * spa_namespace_lock.  The caller must ensure that the spa_t doesn't already
420 * exist by calling spa_lookup() first.
421 */
422spa_t *
423spa_add(const char *name, const char *altroot)
424{
425	spa_t *spa;
426	spa_config_dirent_t *dp;
427
428	ASSERT(MUTEX_HELD(&spa_namespace_lock));
429
430	spa = kmem_zalloc(sizeof (spa_t), KM_SLEEP);
431
432	mutex_init(&spa->spa_async_lock, NULL, MUTEX_DEFAULT, NULL);
433	mutex_init(&spa->spa_scrub_lock, NULL, MUTEX_DEFAULT, NULL);
434	mutex_init(&spa->spa_errlog_lock, NULL, MUTEX_DEFAULT, NULL);
435	mutex_init(&spa->spa_errlist_lock, NULL, MUTEX_DEFAULT, NULL);
436	mutex_init(&spa->spa_sync_bplist.bpl_lock, NULL, MUTEX_DEFAULT, NULL);
437	mutex_init(&spa->spa_history_lock, NULL, MUTEX_DEFAULT, NULL);
438	mutex_init(&spa->spa_props_lock, NULL, MUTEX_DEFAULT, NULL);
439
440	cv_init(&spa->spa_async_cv, NULL, CV_DEFAULT, NULL);
441	cv_init(&spa->spa_scrub_io_cv, NULL, CV_DEFAULT, NULL);
442	cv_init(&spa->spa_suspend_cv, NULL, CV_DEFAULT, NULL);
443
444	(void) strlcpy(spa->spa_name, name, sizeof (spa->spa_name));
445	spa->spa_state = POOL_STATE_UNINITIALIZED;
446	spa->spa_freeze_txg = UINT64_MAX;
447	spa->spa_final_txg = UINT64_MAX;
448
449	refcount_create(&spa->spa_refcount);
450	spa_config_lock_init(spa);
451
452	avl_add(&spa_namespace_avl, spa);
453
454	mutex_init(&spa->spa_suspend_lock, NULL, MUTEX_DEFAULT, NULL);
455
456	/*
457	 * Set the alternate root, if there is one.
458	 */
459	if (altroot) {
460		spa->spa_root = spa_strdup(altroot);
461		spa_active_count++;
462	}
463
464	/*
465	 * Every pool starts with the default cachefile
466	 */
467	list_create(&spa->spa_config_list, sizeof (spa_config_dirent_t),
468	    offsetof(spa_config_dirent_t, scd_link));
469
470	dp = kmem_zalloc(sizeof (spa_config_dirent_t), KM_SLEEP);
471	dp->scd_path = spa_strdup(spa_config_path);
472	list_insert_head(&spa->spa_config_list, dp);
473
474	return (spa);
475}
476
477/*
478 * Removes a spa_t from the namespace, freeing up any memory used.  Requires
479 * spa_namespace_lock.  This is called only after the spa_t has been closed and
480 * deactivated.
481 */
482void
483spa_remove(spa_t *spa)
484{
485	spa_config_dirent_t *dp;
486
487	ASSERT(MUTEX_HELD(&spa_namespace_lock));
488	ASSERT(spa->spa_state == POOL_STATE_UNINITIALIZED);
489
490	avl_remove(&spa_namespace_avl, spa);
491	cv_broadcast(&spa_namespace_cv);
492
493	if (spa->spa_root) {
494		spa_strfree(spa->spa_root);
495		spa_active_count--;
496	}
497
498	while ((dp = list_head(&spa->spa_config_list)) != NULL) {
499		list_remove(&spa->spa_config_list, dp);
500		if (dp->scd_path != NULL)
501			spa_strfree(dp->scd_path);
502		kmem_free(dp, sizeof (spa_config_dirent_t));
503	}
504
505	list_destroy(&spa->spa_config_list);
506
507	spa_config_set(spa, NULL);
508
509	refcount_destroy(&spa->spa_refcount);
510
511	spa_config_lock_destroy(spa);
512
513	cv_destroy(&spa->spa_async_cv);
514	cv_destroy(&spa->spa_scrub_io_cv);
515	cv_destroy(&spa->spa_suspend_cv);
516
517	mutex_destroy(&spa->spa_async_lock);
518	mutex_destroy(&spa->spa_scrub_lock);
519	mutex_destroy(&spa->spa_errlog_lock);
520	mutex_destroy(&spa->spa_errlist_lock);
521	mutex_destroy(&spa->spa_sync_bplist.bpl_lock);
522	mutex_destroy(&spa->spa_history_lock);
523	mutex_destroy(&spa->spa_props_lock);
524	mutex_destroy(&spa->spa_suspend_lock);
525
526	kmem_free(spa, sizeof (spa_t));
527}
528
529/*
530 * Given a pool, return the next pool in the namespace, or NULL if there is
531 * none.  If 'prev' is NULL, return the first pool.
532 */
533spa_t *
534spa_next(spa_t *prev)
535{
536	ASSERT(MUTEX_HELD(&spa_namespace_lock));
537
538	if (prev)
539		return (AVL_NEXT(&spa_namespace_avl, prev));
540	else
541		return (avl_first(&spa_namespace_avl));
542}
543
544/*
545 * ==========================================================================
546 * SPA refcount functions
547 * ==========================================================================
548 */
549
550/*
551 * Add a reference to the given spa_t.  Must have at least one reference, or
552 * have the namespace lock held.
553 */
554void
555spa_open_ref(spa_t *spa, void *tag)
556{
557	ASSERT(refcount_count(&spa->spa_refcount) >= spa->spa_minref ||
558	    MUTEX_HELD(&spa_namespace_lock));
559	(void) refcount_add(&spa->spa_refcount, tag);
560}
561
562/*
563 * Remove a reference to the given spa_t.  Must have at least one reference, or
564 * have the namespace lock held.
565 */
566void
567spa_close(spa_t *spa, void *tag)
568{
569	ASSERT(refcount_count(&spa->spa_refcount) > spa->spa_minref ||
570	    MUTEX_HELD(&spa_namespace_lock));
571	(void) refcount_remove(&spa->spa_refcount, tag);
572}
573
574/*
575 * Check to see if the spa refcount is zero.  Must be called with
576 * spa_namespace_lock held.  We really compare against spa_minref, which is the
577 * number of references acquired when opening a pool
578 */
579boolean_t
580spa_refcount_zero(spa_t *spa)
581{
582	ASSERT(MUTEX_HELD(&spa_namespace_lock));
583
584	return (refcount_count(&spa->spa_refcount) == spa->spa_minref);
585}
586
587/*
588 * ==========================================================================
589 * SPA spare and l2cache tracking
590 * ==========================================================================
591 */
592
593/*
594 * Hot spares and cache devices are tracked using the same code below,
595 * for 'auxiliary' devices.
596 */
597
598typedef struct spa_aux {
599	uint64_t	aux_guid;
600	uint64_t	aux_pool;
601	avl_node_t	aux_avl;
602	int		aux_count;
603} spa_aux_t;
604
605static int
606spa_aux_compare(const void *a, const void *b)
607{
608	const spa_aux_t *sa = a;
609	const spa_aux_t *sb = b;
610
611	if (sa->aux_guid < sb->aux_guid)
612		return (-1);
613	else if (sa->aux_guid > sb->aux_guid)
614		return (1);
615	else
616		return (0);
617}
618
619void
620spa_aux_add(vdev_t *vd, avl_tree_t *avl)
621{
622	avl_index_t where;
623	spa_aux_t search;
624	spa_aux_t *aux;
625
626	search.aux_guid = vd->vdev_guid;
627	if ((aux = avl_find(avl, &search, &where)) != NULL) {
628		aux->aux_count++;
629	} else {
630		aux = kmem_zalloc(sizeof (spa_aux_t), KM_SLEEP);
631		aux->aux_guid = vd->vdev_guid;
632		aux->aux_count = 1;
633		avl_insert(avl, aux, where);
634	}
635}
636
637void
638spa_aux_remove(vdev_t *vd, avl_tree_t *avl)
639{
640	spa_aux_t search;
641	spa_aux_t *aux;
642	avl_index_t where;
643
644	search.aux_guid = vd->vdev_guid;
645	aux = avl_find(avl, &search, &where);
646
647	ASSERT(aux != NULL);
648
649	if (--aux->aux_count == 0) {
650		avl_remove(avl, aux);
651		kmem_free(aux, sizeof (spa_aux_t));
652	} else if (aux->aux_pool == spa_guid(vd->vdev_spa)) {
653		aux->aux_pool = 0ULL;
654	}
655}
656
657boolean_t
658spa_aux_exists(uint64_t guid, uint64_t *pool, int *refcnt, avl_tree_t *avl)
659{
660	spa_aux_t search, *found;
661
662	search.aux_guid = guid;
663	found = avl_find(avl, &search, NULL);
664
665	if (pool) {
666		if (found)
667			*pool = found->aux_pool;
668		else
669			*pool = 0ULL;
670	}
671
672	if (refcnt) {
673		if (found)
674			*refcnt = found->aux_count;
675		else
676			*refcnt = 0;
677	}
678
679	return (found != NULL);
680}
681
682void
683spa_aux_activate(vdev_t *vd, avl_tree_t *avl)
684{
685	spa_aux_t search, *found;
686	avl_index_t where;
687
688	search.aux_guid = vd->vdev_guid;
689	found = avl_find(avl, &search, &where);
690	ASSERT(found != NULL);
691	ASSERT(found->aux_pool == 0ULL);
692
693	found->aux_pool = spa_guid(vd->vdev_spa);
694}
695
696/*
697 * Spares are tracked globally due to the following constraints:
698 *
699 * 	- A spare may be part of multiple pools.
700 * 	- A spare may be added to a pool even if it's actively in use within
701 *	  another pool.
702 * 	- A spare in use in any pool can only be the source of a replacement if
703 *	  the target is a spare in the same pool.
704 *
705 * We keep track of all spares on the system through the use of a reference
706 * counted AVL tree.  When a vdev is added as a spare, or used as a replacement
707 * spare, then we bump the reference count in the AVL tree.  In addition, we set
708 * the 'vdev_isspare' member to indicate that the device is a spare (active or
709 * inactive).  When a spare is made active (used to replace a device in the
710 * pool), we also keep track of which pool its been made a part of.
711 *
712 * The 'spa_spare_lock' protects the AVL tree.  These functions are normally
713 * called under the spa_namespace lock as part of vdev reconfiguration.  The
714 * separate spare lock exists for the status query path, which does not need to
715 * be completely consistent with respect to other vdev configuration changes.
716 */
717
718static int
719spa_spare_compare(const void *a, const void *b)
720{
721	return (spa_aux_compare(a, b));
722}
723
724void
725spa_spare_add(vdev_t *vd)
726{
727	mutex_enter(&spa_spare_lock);
728	ASSERT(!vd->vdev_isspare);
729	spa_aux_add(vd, &spa_spare_avl);
730	vd->vdev_isspare = B_TRUE;
731	mutex_exit(&spa_spare_lock);
732}
733
734void
735spa_spare_remove(vdev_t *vd)
736{
737	mutex_enter(&spa_spare_lock);
738	ASSERT(vd->vdev_isspare);
739	spa_aux_remove(vd, &spa_spare_avl);
740	vd->vdev_isspare = B_FALSE;
741	mutex_exit(&spa_spare_lock);
742}
743
744boolean_t
745spa_spare_exists(uint64_t guid, uint64_t *pool, int *refcnt)
746{
747	boolean_t found;
748
749	mutex_enter(&spa_spare_lock);
750	found = spa_aux_exists(guid, pool, refcnt, &spa_spare_avl);
751	mutex_exit(&spa_spare_lock);
752
753	return (found);
754}
755
756void
757spa_spare_activate(vdev_t *vd)
758{
759	mutex_enter(&spa_spare_lock);
760	ASSERT(vd->vdev_isspare);
761	spa_aux_activate(vd, &spa_spare_avl);
762	mutex_exit(&spa_spare_lock);
763}
764
765/*
766 * Level 2 ARC devices are tracked globally for the same reasons as spares.
767 * Cache devices currently only support one pool per cache device, and so
768 * for these devices the aux reference count is currently unused beyond 1.
769 */
770
771static int
772spa_l2cache_compare(const void *a, const void *b)
773{
774	return (spa_aux_compare(a, b));
775}
776
777void
778spa_l2cache_add(vdev_t *vd)
779{
780	mutex_enter(&spa_l2cache_lock);
781	ASSERT(!vd->vdev_isl2cache);
782	spa_aux_add(vd, &spa_l2cache_avl);
783	vd->vdev_isl2cache = B_TRUE;
784	mutex_exit(&spa_l2cache_lock);
785}
786
787void
788spa_l2cache_remove(vdev_t *vd)
789{
790	mutex_enter(&spa_l2cache_lock);
791	ASSERT(vd->vdev_isl2cache);
792	spa_aux_remove(vd, &spa_l2cache_avl);
793	vd->vdev_isl2cache = B_FALSE;
794	mutex_exit(&spa_l2cache_lock);
795}
796
797boolean_t
798spa_l2cache_exists(uint64_t guid, uint64_t *pool)
799{
800	boolean_t found;
801
802	mutex_enter(&spa_l2cache_lock);
803	found = spa_aux_exists(guid, pool, NULL, &spa_l2cache_avl);
804	mutex_exit(&spa_l2cache_lock);
805
806	return (found);
807}
808
809void
810spa_l2cache_activate(vdev_t *vd)
811{
812	mutex_enter(&spa_l2cache_lock);
813	ASSERT(vd->vdev_isl2cache);
814	spa_aux_activate(vd, &spa_l2cache_avl);
815	mutex_exit(&spa_l2cache_lock);
816}
817
818void
819spa_l2cache_space_update(vdev_t *vd, int64_t space, int64_t alloc)
820{
821	vdev_space_update(vd, space, alloc, B_FALSE);
822}
823
824/*
825 * ==========================================================================
826 * SPA vdev locking
827 * ==========================================================================
828 */
829
830/*
831 * Lock the given spa_t for the purpose of adding or removing a vdev.
832 * Grabs the global spa_namespace_lock plus the spa config lock for writing.
833 * It returns the next transaction group for the spa_t.
834 */
835uint64_t
836spa_vdev_enter(spa_t *spa)
837{
838	mutex_enter(&spa_namespace_lock);
839
840	spa_config_enter(spa, SCL_ALL, spa, RW_WRITER);
841
842	return (spa_last_synced_txg(spa) + 1);
843}
844
845/*
846 * Unlock the spa_t after adding or removing a vdev.  Besides undoing the
847 * locking of spa_vdev_enter(), we also want make sure the transactions have
848 * synced to disk, and then update the global configuration cache with the new
849 * information.
850 */
851int
852spa_vdev_exit(spa_t *spa, vdev_t *vd, uint64_t txg, int error)
853{
854	int config_changed = B_FALSE;
855
856	ASSERT(txg > spa_last_synced_txg(spa));
857
858	spa->spa_pending_vdev = NULL;
859
860	/*
861	 * Reassess the DTLs.
862	 */
863	vdev_dtl_reassess(spa->spa_root_vdev, 0, 0, B_FALSE);
864
865	/*
866	 * If the config changed, notify the scrub thread that it must restart.
867	 */
868	if (error == 0 && !list_is_empty(&spa->spa_config_dirty_list)) {
869		dsl_pool_scrub_restart(spa->spa_dsl_pool);
870		config_changed = B_TRUE;
871	}
872
873	spa_config_exit(spa, SCL_ALL, spa);
874
875	/*
876	 * Note: this txg_wait_synced() is important because it ensures
877	 * that there won't be more than one config change per txg.
878	 * This allows us to use the txg as the generation number.
879	 */
880	if (error == 0)
881		txg_wait_synced(spa->spa_dsl_pool, txg);
882
883	if (vd != NULL) {
884		ASSERT(!vd->vdev_detached || vd->vdev_dtl_smo.smo_object == 0);
885		spa_config_enter(spa, SCL_ALL, spa, RW_WRITER);
886		vdev_free(vd);
887		spa_config_exit(spa, SCL_ALL, spa);
888	}
889
890	/*
891	 * If the config changed, update the config cache.
892	 */
893	if (config_changed)
894		spa_config_sync(spa, B_FALSE, B_TRUE);
895
896	mutex_exit(&spa_namespace_lock);
897
898	return (error);
899}
900
901/*
902 * Lock the given spa_t for the purpose of changing vdev state.
903 */
904void
905spa_vdev_state_enter(spa_t *spa)
906{
907	spa_config_enter(spa, SCL_STATE_ALL, spa, RW_WRITER);
908}
909
910int
911spa_vdev_state_exit(spa_t *spa, vdev_t *vd, int error)
912{
913	if (vd != NULL)
914		vdev_state_dirty(vd->vdev_top);
915
916	spa_config_exit(spa, SCL_STATE_ALL, spa);
917
918	/*
919	 * If anything changed, wait for it to sync.  This ensures that,
920	 * from the system administrator's perspective, zpool(1M) commands
921	 * are synchronous.  This is important for things like zpool offline:
922	 * when the command completes, you expect no further I/O from ZFS.
923	 */
924	if (vd != NULL)
925		txg_wait_synced(spa->spa_dsl_pool, 0);
926
927	return (error);
928}
929
930/*
931 * ==========================================================================
932 * Miscellaneous functions
933 * ==========================================================================
934 */
935
936/*
937 * Rename a spa_t.
938 */
939int
940spa_rename(const char *name, const char *newname)
941{
942	spa_t *spa;
943	int err;
944
945	/*
946	 * Lookup the spa_t and grab the config lock for writing.  We need to
947	 * actually open the pool so that we can sync out the necessary labels.
948	 * It's OK to call spa_open() with the namespace lock held because we
949	 * allow recursive calls for other reasons.
950	 */
951	mutex_enter(&spa_namespace_lock);
952	if ((err = spa_open(name, &spa, FTAG)) != 0) {
953		mutex_exit(&spa_namespace_lock);
954		return (err);
955	}
956
957	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
958
959	avl_remove(&spa_namespace_avl, spa);
960	(void) strlcpy(spa->spa_name, newname, sizeof (spa->spa_name));
961	avl_add(&spa_namespace_avl, spa);
962
963	/*
964	 * Sync all labels to disk with the new names by marking the root vdev
965	 * dirty and waiting for it to sync.  It will pick up the new pool name
966	 * during the sync.
967	 */
968	vdev_config_dirty(spa->spa_root_vdev);
969
970	spa_config_exit(spa, SCL_ALL, FTAG);
971
972	txg_wait_synced(spa->spa_dsl_pool, 0);
973
974	/*
975	 * Sync the updated config cache.
976	 */
977	spa_config_sync(spa, B_FALSE, B_TRUE);
978
979	spa_close(spa, FTAG);
980
981	mutex_exit(&spa_namespace_lock);
982
983	return (0);
984}
985
986
987/*
988 * Determine whether a pool with given pool_guid exists.  If device_guid is
989 * non-zero, determine whether the pool exists *and* contains a device with the
990 * specified device_guid.
991 */
992boolean_t
993spa_guid_exists(uint64_t pool_guid, uint64_t device_guid)
994{
995	spa_t *spa;
996	avl_tree_t *t = &spa_namespace_avl;
997
998	ASSERT(MUTEX_HELD(&spa_namespace_lock));
999
1000	for (spa = avl_first(t); spa != NULL; spa = AVL_NEXT(t, spa)) {
1001		if (spa->spa_state == POOL_STATE_UNINITIALIZED)
1002			continue;
1003		if (spa->spa_root_vdev == NULL)
1004			continue;
1005		if (spa_guid(spa) == pool_guid) {
1006			if (device_guid == 0)
1007				break;
1008
1009			if (vdev_lookup_by_guid(spa->spa_root_vdev,
1010			    device_guid) != NULL)
1011				break;
1012
1013			/*
1014			 * Check any devices we may be in the process of adding.
1015			 */
1016			if (spa->spa_pending_vdev) {
1017				if (vdev_lookup_by_guid(spa->spa_pending_vdev,
1018				    device_guid) != NULL)
1019					break;
1020			}
1021		}
1022	}
1023
1024	return (spa != NULL);
1025}
1026
1027char *
1028spa_strdup(const char *s)
1029{
1030	size_t len;
1031	char *new;
1032
1033	len = strlen(s);
1034	new = kmem_alloc(len + 1, KM_SLEEP);
1035	bcopy(s, new, len);
1036	new[len] = '\0';
1037
1038	return (new);
1039}
1040
1041void
1042spa_strfree(char *s)
1043{
1044	kmem_free(s, strlen(s) + 1);
1045}
1046
1047uint64_t
1048spa_get_random(uint64_t range)
1049{
1050	uint64_t r;
1051
1052	ASSERT(range != 0);
1053
1054	(void) random_get_pseudo_bytes((void *)&r, sizeof (uint64_t));
1055
1056	return (r % range);
1057}
1058
1059void
1060sprintf_blkptr(char *buf, int len, const blkptr_t *bp)
1061{
1062	int d;
1063
1064	if (bp == NULL) {
1065		(void) snprintf(buf, len, "<NULL>");
1066		return;
1067	}
1068
1069	if (BP_IS_HOLE(bp)) {
1070		(void) snprintf(buf, len, "<hole>");
1071		return;
1072	}
1073
1074	(void) snprintf(buf, len, "[L%llu %s] %llxL/%llxP ",
1075	    (u_longlong_t)BP_GET_LEVEL(bp),
1076	    dmu_ot[BP_GET_TYPE(bp)].ot_name,
1077	    (u_longlong_t)BP_GET_LSIZE(bp),
1078	    (u_longlong_t)BP_GET_PSIZE(bp));
1079
1080	for (d = 0; d < BP_GET_NDVAS(bp); d++) {
1081		const dva_t *dva = &bp->blk_dva[d];
1082		(void) snprintf(buf + strlen(buf), len - strlen(buf),
1083		    "DVA[%d]=<%llu:%llx:%llx> ", d,
1084		    (u_longlong_t)DVA_GET_VDEV(dva),
1085		    (u_longlong_t)DVA_GET_OFFSET(dva),
1086		    (u_longlong_t)DVA_GET_ASIZE(dva));
1087	}
1088
1089	(void) snprintf(buf + strlen(buf), len - strlen(buf),
1090	    "%s %s %s %s birth=%llu fill=%llu cksum=%llx:%llx:%llx:%llx",
1091	    zio_checksum_table[BP_GET_CHECKSUM(bp)].ci_name,
1092	    zio_compress_table[BP_GET_COMPRESS(bp)].ci_name,
1093	    BP_GET_BYTEORDER(bp) == 0 ? "BE" : "LE",
1094	    BP_IS_GANG(bp) ? "gang" : "contiguous",
1095	    (u_longlong_t)bp->blk_birth,
1096	    (u_longlong_t)bp->blk_fill,
1097	    (u_longlong_t)bp->blk_cksum.zc_word[0],
1098	    (u_longlong_t)bp->blk_cksum.zc_word[1],
1099	    (u_longlong_t)bp->blk_cksum.zc_word[2],
1100	    (u_longlong_t)bp->blk_cksum.zc_word[3]);
1101}
1102
1103void
1104spa_freeze(spa_t *spa)
1105{
1106	uint64_t freeze_txg = 0;
1107
1108	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
1109	if (spa->spa_freeze_txg == UINT64_MAX) {
1110		freeze_txg = spa_last_synced_txg(spa) + TXG_SIZE;
1111		spa->spa_freeze_txg = freeze_txg;
1112	}
1113	spa_config_exit(spa, SCL_ALL, FTAG);
1114	if (freeze_txg != 0)
1115		txg_wait_synced(spa_get_dsl(spa), freeze_txg);
1116}
1117
1118void
1119zfs_panic_recover(const char *fmt, ...)
1120{
1121	va_list adx;
1122
1123	va_start(adx, fmt);
1124	vcmn_err(zfs_recover ? CE_WARN : CE_PANIC, fmt, adx);
1125	va_end(adx);
1126}
1127
1128/*
1129 * ==========================================================================
1130 * Accessor functions
1131 * ==========================================================================
1132 */
1133
1134boolean_t
1135spa_shutting_down(spa_t *spa)
1136{
1137	return (spa->spa_async_suspended);
1138}
1139
1140dsl_pool_t *
1141spa_get_dsl(spa_t *spa)
1142{
1143	return (spa->spa_dsl_pool);
1144}
1145
1146blkptr_t *
1147spa_get_rootblkptr(spa_t *spa)
1148{
1149	return (&spa->spa_ubsync.ub_rootbp);
1150}
1151
1152void
1153spa_set_rootblkptr(spa_t *spa, const blkptr_t *bp)
1154{
1155	spa->spa_uberblock.ub_rootbp = *bp;
1156}
1157
1158void
1159spa_altroot(spa_t *spa, char *buf, size_t buflen)
1160{
1161	if (spa->spa_root == NULL)
1162		buf[0] = '\0';
1163	else
1164		(void) strncpy(buf, spa->spa_root, buflen);
1165}
1166
1167int
1168spa_sync_pass(spa_t *spa)
1169{
1170	return (spa->spa_sync_pass);
1171}
1172
1173char *
1174spa_name(spa_t *spa)
1175{
1176	return (spa->spa_name);
1177}
1178
1179uint64_t
1180spa_guid(spa_t *spa)
1181{
1182	/*
1183	 * If we fail to parse the config during spa_load(), we can go through
1184	 * the error path (which posts an ereport) and end up here with no root
1185	 * vdev.  We stash the original pool guid in 'spa_load_guid' to handle
1186	 * this case.
1187	 */
1188	if (spa->spa_root_vdev != NULL)
1189		return (spa->spa_root_vdev->vdev_guid);
1190	else
1191		return (spa->spa_load_guid);
1192}
1193
1194uint64_t
1195spa_last_synced_txg(spa_t *spa)
1196{
1197	return (spa->spa_ubsync.ub_txg);
1198}
1199
1200uint64_t
1201spa_first_txg(spa_t *spa)
1202{
1203	return (spa->spa_first_txg);
1204}
1205
1206pool_state_t
1207spa_state(spa_t *spa)
1208{
1209	return (spa->spa_state);
1210}
1211
1212uint64_t
1213spa_freeze_txg(spa_t *spa)
1214{
1215	return (spa->spa_freeze_txg);
1216}
1217
1218/*
1219 * Return how much space is allocated in the pool (ie. sum of all asize)
1220 */
1221uint64_t
1222spa_get_alloc(spa_t *spa)
1223{
1224	return (spa->spa_root_vdev->vdev_stat.vs_alloc);
1225}
1226
1227/*
1228 * Return how much (raid-z inflated) space there is in the pool.
1229 */
1230uint64_t
1231spa_get_space(spa_t *spa)
1232{
1233	return (spa->spa_root_vdev->vdev_stat.vs_space);
1234}
1235
1236/*
1237 * Return the amount of raid-z-deflated space in the pool.
1238 */
1239uint64_t
1240spa_get_dspace(spa_t *spa)
1241{
1242	if (spa->spa_deflate)
1243		return (spa->spa_root_vdev->vdev_stat.vs_dspace);
1244	else
1245		return (spa->spa_root_vdev->vdev_stat.vs_space);
1246}
1247
1248/* ARGSUSED */
1249uint64_t
1250spa_get_asize(spa_t *spa, uint64_t lsize)
1251{
1252	/*
1253	 * For now, the worst case is 512-byte RAID-Z blocks, in which
1254	 * case the space requirement is exactly 2x; so just assume that.
1255	 * Add to this the fact that we can have up to 3 DVAs per bp, and
1256	 * we have to multiply by a total of 6x.
1257	 */
1258	return (lsize * 6);
1259}
1260
1261/*
1262 * Return the failure mode that has been set to this pool. The default
1263 * behavior will be to block all I/Os when a complete failure occurs.
1264 */
1265uint8_t
1266spa_get_failmode(spa_t *spa)
1267{
1268	return (spa->spa_failmode);
1269}
1270
1271boolean_t
1272spa_suspended(spa_t *spa)
1273{
1274	return (spa->spa_suspended);
1275}
1276
1277uint64_t
1278spa_version(spa_t *spa)
1279{
1280	return (spa->spa_ubsync.ub_version);
1281}
1282
1283/*
1284 * if there is a pool on top of zvols, there can be a situation where
1285 * a second vdev_set_state ioctl can come in (grabbing the pool's config
1286 * lock and then calling into the zvol's pool) before the config has
1287 * synced out from a previous vdev_set_state ioctl, resulting in
1288 * deadlock.
1289 */
1290boolean_t
1291spa_uses_zvols(spa_t *spa)
1292{
1293	boolean_t i;
1294
1295	spa_config_enter(spa, SCL_STATE_ALL, spa, RW_READER);
1296	i = vdev_uses_zvols(spa->spa_root_vdev);
1297	spa_config_exit(spa, SCL_STATE_ALL, spa);
1298	return (i);
1299}
1300
1301int
1302spa_max_replication(spa_t *spa)
1303{
1304	/*
1305	 * As of SPA_VERSION == SPA_VERSION_DITTO_BLOCKS, we are able to
1306	 * handle BPs with more than one DVA allocated.  Set our max
1307	 * replication level accordingly.
1308	 */
1309	if (spa_version(spa) < SPA_VERSION_DITTO_BLOCKS)
1310		return (1);
1311	return (MIN(SPA_DVAS_PER_BP, spa_max_replication_override));
1312}
1313
1314uint64_t
1315bp_get_dasize(spa_t *spa, const blkptr_t *bp)
1316{
1317	int sz = 0, i;
1318
1319	if (!spa->spa_deflate)
1320		return (BP_GET_ASIZE(bp));
1321
1322	spa_config_enter(spa, SCL_VDEV, FTAG, RW_READER);
1323	for (i = 0; i < SPA_DVAS_PER_BP; i++) {
1324		vdev_t *vd =
1325		    vdev_lookup_top(spa, DVA_GET_VDEV(&bp->blk_dva[i]));
1326		if (vd)
1327			sz += (DVA_GET_ASIZE(&bp->blk_dva[i]) >>
1328			    SPA_MINBLOCKSHIFT) * vd->vdev_deflate_ratio;
1329	}
1330	spa_config_exit(spa, SCL_VDEV, FTAG);
1331	return (sz);
1332}
1333
1334/*
1335 * ==========================================================================
1336 * Initialization and Termination
1337 * ==========================================================================
1338 */
1339
1340static int
1341spa_name_compare(const void *a1, const void *a2)
1342{
1343	const spa_t *s1 = a1;
1344	const spa_t *s2 = a2;
1345	int s;
1346
1347	s = strcmp(s1->spa_name, s2->spa_name);
1348	if (s > 0)
1349		return (1);
1350	if (s < 0)
1351		return (-1);
1352	return (0);
1353}
1354
1355int
1356spa_busy(void)
1357{
1358	return (spa_active_count);
1359}
1360
1361void
1362spa_boot_init()
1363{
1364	spa_config_load();
1365}
1366
1367void
1368spa_init(int mode)
1369{
1370	mutex_init(&spa_namespace_lock, NULL, MUTEX_DEFAULT, NULL);
1371	mutex_init(&spa_spare_lock, NULL, MUTEX_DEFAULT, NULL);
1372	mutex_init(&spa_l2cache_lock, NULL, MUTEX_DEFAULT, NULL);
1373	cv_init(&spa_namespace_cv, NULL, CV_DEFAULT, NULL);
1374
1375	avl_create(&spa_namespace_avl, spa_name_compare, sizeof (spa_t),
1376	    offsetof(spa_t, spa_avl));
1377
1378	avl_create(&spa_spare_avl, spa_spare_compare, sizeof (spa_aux_t),
1379	    offsetof(spa_aux_t, aux_avl));
1380
1381	avl_create(&spa_l2cache_avl, spa_l2cache_compare, sizeof (spa_aux_t),
1382	    offsetof(spa_aux_t, aux_avl));
1383
1384	spa_mode_global = mode;
1385
1386	refcount_init();
1387	unique_init();
1388	zio_init();
1389	dmu_init();
1390	zil_init();
1391	vdev_cache_stat_init();
1392	zfs_prop_init();
1393	zpool_prop_init();
1394	spa_config_load();
1395	l2arc_start();
1396}
1397
1398void
1399spa_fini(void)
1400{
1401	l2arc_stop();
1402
1403	spa_evict_all();
1404
1405	vdev_cache_stat_fini();
1406	zil_fini();
1407	dmu_fini();
1408	zio_fini();
1409	unique_fini();
1410	refcount_fini();
1411
1412	avl_destroy(&spa_namespace_avl);
1413	avl_destroy(&spa_spare_avl);
1414	avl_destroy(&spa_l2cache_avl);
1415
1416	cv_destroy(&spa_namespace_cv);
1417	mutex_destroy(&spa_namespace_lock);
1418	mutex_destroy(&spa_spare_lock);
1419	mutex_destroy(&spa_l2cache_lock);
1420}
1421
1422/*
1423 * Return whether this pool has slogs. No locking needed.
1424 * It's not a problem if the wrong answer is returned as it's only for
1425 * performance and not correctness
1426 */
1427boolean_t
1428spa_has_slogs(spa_t *spa)
1429{
1430	return (spa->spa_log_class->mc_rotor != NULL);
1431}
1432
1433/*
1434 * Return whether this pool is the root pool.
1435 */
1436boolean_t
1437spa_is_root(spa_t *spa)
1438{
1439	return (spa->spa_is_root);
1440}
1441
1442boolean_t
1443spa_writeable(spa_t *spa)
1444{
1445	return (!!(spa->spa_mode & FWRITE));
1446}
1447
1448int
1449spa_mode(spa_t *spa)
1450{
1451	return (spa->spa_mode);
1452}
1453