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) 2011, 2015 by Delphix. All rights reserved.
24 * Copyright 2015 Nexenta Systems, Inc.  All rights reserved.
25 * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
26 * Copyright 2013 Saso Kiselkov. All rights reserved.
27 * Copyright (c) 2014 Integros [integros.com]
28 */
29
30#include <sys/zfs_context.h>
31#include <sys/spa_impl.h>
32#include <sys/spa_boot.h>
33#include <sys/zio.h>
34#include <sys/zio_checksum.h>
35#include <sys/zio_compress.h>
36#include <sys/dmu.h>
37#include <sys/dmu_tx.h>
38#include <sys/zap.h>
39#include <sys/zil.h>
40#include <sys/vdev_impl.h>
41#include <sys/metaslab.h>
42#include <sys/uberblock_impl.h>
43#include <sys/txg.h>
44#include <sys/avl.h>
45#include <sys/unique.h>
46#include <sys/dsl_pool.h>
47#include <sys/dsl_dir.h>
48#include <sys/dsl_prop.h>
49#include <sys/dsl_scan.h>
50#include <sys/fs/zfs.h>
51#include <sys/metaslab_impl.h>
52#include <sys/arc.h>
53#include <sys/ddt.h>
54#include "zfs_prop.h"
55#include <sys/zfeature.h>
56
57/*
58 * SPA locking
59 *
60 * There are four basic locks for managing spa_t structures:
61 *
62 * spa_namespace_lock (global mutex)
63 *
64 *	This lock must be acquired to do any of the following:
65 *
66 *		- Lookup a spa_t by name
67 *		- Add or remove a spa_t from the namespace
68 *		- Increase spa_refcount from non-zero
69 *		- Check if spa_refcount is zero
70 *		- Rename a spa_t
71 *		- add/remove/attach/detach devices
72 *		- Held for the duration of create/destroy/import/export
73 *
74 *	It does not need to handle recursion.  A create or destroy may
75 *	reference objects (files or zvols) in other pools, but by
76 *	definition they must have an existing reference, and will never need
77 *	to lookup a spa_t by name.
78 *
79 * spa_refcount (per-spa refcount_t protected by mutex)
80 *
81 *	This reference count keep track of any active users of the spa_t.  The
82 *	spa_t cannot be destroyed or freed while this is non-zero.  Internally,
83 *	the refcount is never really 'zero' - opening a pool implicitly keeps
84 *	some references in the DMU.  Internally we check against spa_minref, but
85 *	present the image of a zero/non-zero value to consumers.
86 *
87 * spa_config_lock[] (per-spa array of rwlocks)
88 *
89 *	This protects the spa_t from config changes, and must be held in
90 *	the following circumstances:
91 *
92 *		- RW_READER to perform I/O to the spa
93 *		- RW_WRITER to change the vdev config
94 *
95 * The locking order is fairly straightforward:
96 *
97 *		spa_namespace_lock	->	spa_refcount
98 *
99 *	The namespace lock must be acquired to increase the refcount from 0
100 *	or to check if it is zero.
101 *
102 *		spa_refcount		->	spa_config_lock[]
103 *
104 *	There must be at least one valid reference on the spa_t to acquire
105 *	the config lock.
106 *
107 *		spa_namespace_lock	->	spa_config_lock[]
108 *
109 *	The namespace lock must always be taken before the config lock.
110 *
111 *
112 * The spa_namespace_lock can be acquired directly and is globally visible.
113 *
114 * The namespace is manipulated using the following functions, all of which
115 * require the spa_namespace_lock to be held.
116 *
117 *	spa_lookup()		Lookup a spa_t by name.
118 *
119 *	spa_add()		Create a new spa_t in the namespace.
120 *
121 *	spa_remove()		Remove a spa_t from the namespace.  This also
122 *				frees up any memory associated with the spa_t.
123 *
124 *	spa_next()		Returns the next spa_t in the system, or the
125 *				first if NULL is passed.
126 *
127 *	spa_evict_all()		Shutdown and remove all spa_t structures in
128 *				the system.
129 *
130 *	spa_guid_exists()	Determine whether a pool/device guid exists.
131 *
132 * The spa_refcount is manipulated using the following functions:
133 *
134 *	spa_open_ref()		Adds a reference to the given spa_t.  Must be
135 *				called with spa_namespace_lock held if the
136 *				refcount is currently zero.
137 *
138 *	spa_close()		Remove a reference from the spa_t.  This will
139 *				not free the spa_t or remove it from the
140 *				namespace.  No locking is required.
141 *
142 *	spa_refcount_zero()	Returns true if the refcount is currently
143 *				zero.  Must be called with spa_namespace_lock
144 *				held.
145 *
146 * The spa_config_lock[] is an array of rwlocks, ordered as follows:
147 * SCL_CONFIG > SCL_STATE > SCL_ALLOC > SCL_ZIO > SCL_FREE > SCL_VDEV.
148 * spa_config_lock[] is manipulated with spa_config_{enter,exit,held}().
149 *
150 * To read the configuration, it suffices to hold one of these locks as reader.
151 * To modify the configuration, you must hold all locks as writer.  To modify
152 * vdev state without altering the vdev tree's topology (e.g. online/offline),
153 * you must hold SCL_STATE and SCL_ZIO as writer.
154 *
155 * We use these distinct config locks to avoid recursive lock entry.
156 * For example, spa_sync() (which holds SCL_CONFIG as reader) induces
157 * block allocations (SCL_ALLOC), which may require reading space maps
158 * from disk (dmu_read() -> zio_read() -> SCL_ZIO).
159 *
160 * The spa config locks cannot be normal rwlocks because we need the
161 * ability to hand off ownership.  For example, SCL_ZIO is acquired
162 * by the issuing thread and later released by an interrupt thread.
163 * They do, however, obey the usual write-wanted semantics to prevent
164 * writer (i.e. system administrator) starvation.
165 *
166 * The lock acquisition rules are as follows:
167 *
168 * SCL_CONFIG
169 *	Protects changes to the vdev tree topology, such as vdev
170 *	add/remove/attach/detach.  Protects the dirty config list
171 *	(spa_config_dirty_list) and the set of spares and l2arc devices.
172 *
173 * SCL_STATE
174 *	Protects changes to pool state and vdev state, such as vdev
175 *	online/offline/fault/degrade/clear.  Protects the dirty state list
176 *	(spa_state_dirty_list) and global pool state (spa_state).
177 *
178 * SCL_ALLOC
179 *	Protects changes to metaslab groups and classes.
180 *	Held as reader by metaslab_alloc() and metaslab_claim().
181 *
182 * SCL_ZIO
183 *	Held by bp-level zios (those which have no io_vd upon entry)
184 *	to prevent changes to the vdev tree.  The bp-level zio implicitly
185 *	protects all of its vdev child zios, which do not hold SCL_ZIO.
186 *
187 * SCL_FREE
188 *	Protects changes to metaslab groups and classes.
189 *	Held as reader by metaslab_free().  SCL_FREE is distinct from
190 *	SCL_ALLOC, and lower than SCL_ZIO, so that we can safely free
191 *	blocks in zio_done() while another i/o that holds either
192 *	SCL_ALLOC or SCL_ZIO is waiting for this i/o to complete.
193 *
194 * SCL_VDEV
195 *	Held as reader to prevent changes to the vdev tree during trivial
196 *	inquiries such as bp_get_dsize().  SCL_VDEV is distinct from the
197 *	other locks, and lower than all of them, to ensure that it's safe
198 *	to acquire regardless of caller context.
199 *
200 * In addition, the following rules apply:
201 *
202 * (a)	spa_props_lock protects pool properties, spa_config and spa_config_list.
203 *	The lock ordering is SCL_CONFIG > spa_props_lock.
204 *
205 * (b)	I/O operations on leaf vdevs.  For any zio operation that takes
206 *	an explicit vdev_t argument -- such as zio_ioctl(), zio_read_phys(),
207 *	or zio_write_phys() -- the caller must ensure that the config cannot
208 *	cannot change in the interim, and that the vdev cannot be reopened.
209 *	SCL_STATE as reader suffices for both.
210 *
211 * The vdev configuration is protected by spa_vdev_enter() / spa_vdev_exit().
212 *
213 *	spa_vdev_enter()	Acquire the namespace lock and the config lock
214 *				for writing.
215 *
216 *	spa_vdev_exit()		Release the config lock, wait for all I/O
217 *				to complete, sync the updated configs to the
218 *				cache, and release the namespace lock.
219 *
220 * vdev state is protected by spa_vdev_state_enter() / spa_vdev_state_exit().
221 * Like spa_vdev_enter/exit, these are convenience wrappers -- the actual
222 * locking is, always, based on spa_namespace_lock and spa_config_lock[].
223 *
224 * spa_rename() is also implemented within this file since it requires
225 * manipulation of the namespace.
226 */
227
228static avl_tree_t spa_namespace_avl;
229kmutex_t spa_namespace_lock;
230static kcondvar_t spa_namespace_cv;
231static int spa_active_count;
232int spa_max_replication_override = SPA_DVAS_PER_BP;
233
234static kmutex_t spa_spare_lock;
235static avl_tree_t spa_spare_avl;
236static kmutex_t spa_l2cache_lock;
237static avl_tree_t spa_l2cache_avl;
238
239kmem_cache_t *spa_buffer_pool;
240int spa_mode_global;
241
242#ifdef ZFS_DEBUG
243/* Everything except dprintf and spa is on by default in debug builds */
244int zfs_flags = ~(ZFS_DEBUG_DPRINTF | ZFS_DEBUG_SPA);
245#else
246int zfs_flags = 0;
247#endif
248
249/*
250 * zfs_recover can be set to nonzero to attempt to recover from
251 * otherwise-fatal errors, typically caused by on-disk corruption.  When
252 * set, calls to zfs_panic_recover() will turn into warning messages.
253 * This should only be used as a last resort, as it typically results
254 * in leaked space, or worse.
255 */
256boolean_t zfs_recover = B_FALSE;
257
258/*
259 * If destroy encounters an EIO while reading metadata (e.g. indirect
260 * blocks), space referenced by the missing metadata can not be freed.
261 * Normally this causes the background destroy to become "stalled", as
262 * it is unable to make forward progress.  While in this stalled state,
263 * all remaining space to free from the error-encountering filesystem is
264 * "temporarily leaked".  Set this flag to cause it to ignore the EIO,
265 * permanently leak the space from indirect blocks that can not be read,
266 * and continue to free everything else that it can.
267 *
268 * The default, "stalling" behavior is useful if the storage partially
269 * fails (i.e. some but not all i/os fail), and then later recovers.  In
270 * this case, we will be able to continue pool operations while it is
271 * partially failed, and when it recovers, we can continue to free the
272 * space, with no leaks.  However, note that this case is actually
273 * fairly rare.
274 *
275 * Typically pools either (a) fail completely (but perhaps temporarily,
276 * e.g. a top-level vdev going offline), or (b) have localized,
277 * permanent errors (e.g. disk returns the wrong data due to bit flip or
278 * firmware bug).  In case (a), this setting does not matter because the
279 * pool will be suspended and the sync thread will not be able to make
280 * forward progress regardless.  In case (b), because the error is
281 * permanent, the best we can do is leak the minimum amount of space,
282 * which is what setting this flag will do.  Therefore, it is reasonable
283 * for this flag to normally be set, but we chose the more conservative
284 * approach of not setting it, so that there is no possibility of
285 * leaking space in the "partial temporary" failure case.
286 */
287boolean_t zfs_free_leak_on_eio = B_FALSE;
288
289/*
290 * Expiration time in milliseconds. This value has two meanings. First it is
291 * used to determine when the spa_deadman() logic should fire. By default the
292 * spa_deadman() will fire if spa_sync() has not completed in 1000 seconds.
293 * Secondly, the value determines if an I/O is considered "hung". Any I/O that
294 * has not completed in zfs_deadman_synctime_ms is considered "hung" resulting
295 * in a system panic.
296 */
297uint64_t zfs_deadman_synctime_ms = 1000000ULL;
298
299/*
300 * Check time in milliseconds. This defines the frequency at which we check
301 * for hung I/O.
302 */
303uint64_t zfs_deadman_checktime_ms = 5000ULL;
304
305/*
306 * Override the zfs deadman behavior via /etc/system. By default the
307 * deadman is enabled except on VMware and sparc deployments.
308 */
309int zfs_deadman_enabled = -1;
310
311/*
312 * The worst case is single-sector max-parity RAID-Z blocks, in which
313 * case the space requirement is exactly (VDEV_RAIDZ_MAXPARITY + 1)
314 * times the size; so just assume that.  Add to this the fact that
315 * we can have up to 3 DVAs per bp, and one more factor of 2 because
316 * the block may be dittoed with up to 3 DVAs by ddt_sync().  All together,
317 * the worst case is:
318 *     (VDEV_RAIDZ_MAXPARITY + 1) * SPA_DVAS_PER_BP * 2 == 24
319 */
320int spa_asize_inflation = 24;
321
322/*
323 * Normally, we don't allow the last 3.2% (1/(2^spa_slop_shift)) of space in
324 * the pool to be consumed.  This ensures that we don't run the pool
325 * completely out of space, due to unaccounted changes (e.g. to the MOS).
326 * It also limits the worst-case time to allocate space.  If we have
327 * less than this amount of free space, most ZPL operations (e.g. write,
328 * create) will return ENOSPC.
329 *
330 * Certain operations (e.g. file removal, most administrative actions) can
331 * use half the slop space.  They will only return ENOSPC if less than half
332 * the slop space is free.  Typically, once the pool has less than the slop
333 * space free, the user will use these operations to free up space in the pool.
334 * These are the operations that call dsl_pool_adjustedsize() with the netfree
335 * argument set to TRUE.
336 *
337 * A very restricted set of operations are always permitted, regardless of
338 * the amount of free space.  These are the operations that call
339 * dsl_sync_task(ZFS_SPACE_CHECK_NONE), e.g. "zfs destroy".  If these
340 * operations result in a net increase in the amount of space used,
341 * it is possible to run the pool completely out of space, causing it to
342 * be permanently read-only.
343 *
344 * Note that on very small pools, the slop space will be larger than
345 * 3.2%, in an effort to have it be at least spa_min_slop (128MB),
346 * but we never allow it to be more than half the pool size.
347 *
348 * See also the comments in zfs_space_check_t.
349 */
350int spa_slop_shift = 5;
351uint64_t spa_min_slop = 128 * 1024 * 1024;
352
353/*
354 * ==========================================================================
355 * SPA config locking
356 * ==========================================================================
357 */
358static void
359spa_config_lock_init(spa_t *spa)
360{
361	for (int i = 0; i < SCL_LOCKS; i++) {
362		spa_config_lock_t *scl = &spa->spa_config_lock[i];
363		mutex_init(&scl->scl_lock, NULL, MUTEX_DEFAULT, NULL);
364		cv_init(&scl->scl_cv, NULL, CV_DEFAULT, NULL);
365		refcount_create_untracked(&scl->scl_count);
366		scl->scl_writer = NULL;
367		scl->scl_write_wanted = 0;
368	}
369}
370
371static void
372spa_config_lock_destroy(spa_t *spa)
373{
374	for (int i = 0; i < SCL_LOCKS; i++) {
375		spa_config_lock_t *scl = &spa->spa_config_lock[i];
376		mutex_destroy(&scl->scl_lock);
377		cv_destroy(&scl->scl_cv);
378		refcount_destroy(&scl->scl_count);
379		ASSERT(scl->scl_writer == NULL);
380		ASSERT(scl->scl_write_wanted == 0);
381	}
382}
383
384int
385spa_config_tryenter(spa_t *spa, int locks, void *tag, krw_t rw)
386{
387	for (int i = 0; i < SCL_LOCKS; i++) {
388		spa_config_lock_t *scl = &spa->spa_config_lock[i];
389		if (!(locks & (1 << i)))
390			continue;
391		mutex_enter(&scl->scl_lock);
392		if (rw == RW_READER) {
393			if (scl->scl_writer || scl->scl_write_wanted) {
394				mutex_exit(&scl->scl_lock);
395				spa_config_exit(spa, locks & ((1 << i) - 1),
396				    tag);
397				return (0);
398			}
399		} else {
400			ASSERT(scl->scl_writer != curthread);
401			if (!refcount_is_zero(&scl->scl_count)) {
402				mutex_exit(&scl->scl_lock);
403				spa_config_exit(spa, locks & ((1 << i) - 1),
404				    tag);
405				return (0);
406			}
407			scl->scl_writer = curthread;
408		}
409		(void) refcount_add(&scl->scl_count, tag);
410		mutex_exit(&scl->scl_lock);
411	}
412	return (1);
413}
414
415void
416spa_config_enter(spa_t *spa, int locks, void *tag, krw_t rw)
417{
418	int wlocks_held = 0;
419
420	ASSERT3U(SCL_LOCKS, <, sizeof (wlocks_held) * NBBY);
421
422	for (int i = 0; i < SCL_LOCKS; i++) {
423		spa_config_lock_t *scl = &spa->spa_config_lock[i];
424		if (scl->scl_writer == curthread)
425			wlocks_held |= (1 << i);
426		if (!(locks & (1 << i)))
427			continue;
428		mutex_enter(&scl->scl_lock);
429		if (rw == RW_READER) {
430			while (scl->scl_writer || scl->scl_write_wanted) {
431				cv_wait(&scl->scl_cv, &scl->scl_lock);
432			}
433		} else {
434			ASSERT(scl->scl_writer != curthread);
435			while (!refcount_is_zero(&scl->scl_count)) {
436				scl->scl_write_wanted++;
437				cv_wait(&scl->scl_cv, &scl->scl_lock);
438				scl->scl_write_wanted--;
439			}
440			scl->scl_writer = curthread;
441		}
442		(void) refcount_add(&scl->scl_count, tag);
443		mutex_exit(&scl->scl_lock);
444	}
445	ASSERT(wlocks_held <= locks);
446}
447
448void
449spa_config_exit(spa_t *spa, int locks, void *tag)
450{
451	for (int i = SCL_LOCKS - 1; i >= 0; i--) {
452		spa_config_lock_t *scl = &spa->spa_config_lock[i];
453		if (!(locks & (1 << i)))
454			continue;
455		mutex_enter(&scl->scl_lock);
456		ASSERT(!refcount_is_zero(&scl->scl_count));
457		if (refcount_remove(&scl->scl_count, tag) == 0) {
458			ASSERT(scl->scl_writer == NULL ||
459			    scl->scl_writer == curthread);
460			scl->scl_writer = NULL;	/* OK in either case */
461			cv_broadcast(&scl->scl_cv);
462		}
463		mutex_exit(&scl->scl_lock);
464	}
465}
466
467int
468spa_config_held(spa_t *spa, int locks, krw_t rw)
469{
470	int locks_held = 0;
471
472	for (int i = 0; i < SCL_LOCKS; i++) {
473		spa_config_lock_t *scl = &spa->spa_config_lock[i];
474		if (!(locks & (1 << i)))
475			continue;
476		if ((rw == RW_READER && !refcount_is_zero(&scl->scl_count)) ||
477		    (rw == RW_WRITER && scl->scl_writer == curthread))
478			locks_held |= 1 << i;
479	}
480
481	return (locks_held);
482}
483
484/*
485 * ==========================================================================
486 * SPA namespace functions
487 * ==========================================================================
488 */
489
490/*
491 * Lookup the named spa_t in the AVL tree.  The spa_namespace_lock must be held.
492 * Returns NULL if no matching spa_t is found.
493 */
494spa_t *
495spa_lookup(const char *name)
496{
497	static spa_t search;	/* spa_t is large; don't allocate on stack */
498	spa_t *spa;
499	avl_index_t where;
500	char *cp;
501
502	ASSERT(MUTEX_HELD(&spa_namespace_lock));
503
504	(void) strlcpy(search.spa_name, name, sizeof (search.spa_name));
505
506	/*
507	 * If it's a full dataset name, figure out the pool name and
508	 * just use that.
509	 */
510	cp = strpbrk(search.spa_name, "/@#");
511	if (cp != NULL)
512		*cp = '\0';
513
514	spa = avl_find(&spa_namespace_avl, &search, &where);
515
516	return (spa);
517}
518
519/*
520 * Fires when spa_sync has not completed within zfs_deadman_synctime_ms.
521 * If the zfs_deadman_enabled flag is set then it inspects all vdev queues
522 * looking for potentially hung I/Os.
523 */
524void
525spa_deadman(void *arg)
526{
527	spa_t *spa = arg;
528
529	/*
530	 * Disable the deadman timer if the pool is suspended.
531	 */
532	if (spa_suspended(spa)) {
533		VERIFY(cyclic_reprogram(spa->spa_deadman_cycid, CY_INFINITY));
534		return;
535	}
536
537	zfs_dbgmsg("slow spa_sync: started %llu seconds ago, calls %llu",
538	    (gethrtime() - spa->spa_sync_starttime) / NANOSEC,
539	    ++spa->spa_deadman_calls);
540	if (zfs_deadman_enabled)
541		vdev_deadman(spa->spa_root_vdev);
542}
543
544/*
545 * Create an uninitialized spa_t with the given name.  Requires
546 * spa_namespace_lock.  The caller must ensure that the spa_t doesn't already
547 * exist by calling spa_lookup() first.
548 */
549spa_t *
550spa_add(const char *name, nvlist_t *config, const char *altroot)
551{
552	spa_t *spa;
553	spa_config_dirent_t *dp;
554	cyc_handler_t hdlr;
555	cyc_time_t when;
556
557	ASSERT(MUTEX_HELD(&spa_namespace_lock));
558
559	spa = kmem_zalloc(sizeof (spa_t), KM_SLEEP);
560
561	mutex_init(&spa->spa_async_lock, NULL, MUTEX_DEFAULT, NULL);
562	mutex_init(&spa->spa_errlist_lock, NULL, MUTEX_DEFAULT, NULL);
563	mutex_init(&spa->spa_errlog_lock, NULL, MUTEX_DEFAULT, NULL);
564	mutex_init(&spa->spa_evicting_os_lock, NULL, MUTEX_DEFAULT, NULL);
565	mutex_init(&spa->spa_history_lock, NULL, MUTEX_DEFAULT, NULL);
566	mutex_init(&spa->spa_proc_lock, NULL, MUTEX_DEFAULT, NULL);
567	mutex_init(&spa->spa_props_lock, NULL, MUTEX_DEFAULT, NULL);
568	mutex_init(&spa->spa_cksum_tmpls_lock, NULL, MUTEX_DEFAULT, NULL);
569	mutex_init(&spa->spa_scrub_lock, NULL, MUTEX_DEFAULT, NULL);
570	mutex_init(&spa->spa_suspend_lock, NULL, MUTEX_DEFAULT, NULL);
571	mutex_init(&spa->spa_vdev_top_lock, NULL, MUTEX_DEFAULT, NULL);
572	mutex_init(&spa->spa_iokstat_lock, NULL, MUTEX_DEFAULT, NULL);
573
574	cv_init(&spa->spa_async_cv, NULL, CV_DEFAULT, NULL);
575	cv_init(&spa->spa_evicting_os_cv, NULL, CV_DEFAULT, NULL);
576	cv_init(&spa->spa_proc_cv, NULL, CV_DEFAULT, NULL);
577	cv_init(&spa->spa_scrub_io_cv, NULL, CV_DEFAULT, NULL);
578	cv_init(&spa->spa_suspend_cv, NULL, CV_DEFAULT, NULL);
579
580	for (int t = 0; t < TXG_SIZE; t++)
581		bplist_create(&spa->spa_free_bplist[t]);
582
583	(void) strlcpy(spa->spa_name, name, sizeof (spa->spa_name));
584	spa->spa_state = POOL_STATE_UNINITIALIZED;
585	spa->spa_freeze_txg = UINT64_MAX;
586	spa->spa_final_txg = UINT64_MAX;
587	spa->spa_load_max_txg = UINT64_MAX;
588	spa->spa_proc = &p0;
589	spa->spa_proc_state = SPA_PROC_NONE;
590
591	hdlr.cyh_func = spa_deadman;
592	hdlr.cyh_arg = spa;
593	hdlr.cyh_level = CY_LOW_LEVEL;
594
595	spa->spa_deadman_synctime = MSEC2NSEC(zfs_deadman_synctime_ms);
596
597	/*
598	 * This determines how often we need to check for hung I/Os after
599	 * the cyclic has already fired. Since checking for hung I/Os is
600	 * an expensive operation we don't want to check too frequently.
601	 * Instead wait for 5 seconds before checking again.
602	 */
603	when.cyt_interval = MSEC2NSEC(zfs_deadman_checktime_ms);
604	when.cyt_when = CY_INFINITY;
605	mutex_enter(&cpu_lock);
606	spa->spa_deadman_cycid = cyclic_add(&hdlr, &when);
607	mutex_exit(&cpu_lock);
608
609	refcount_create(&spa->spa_refcount);
610	spa_config_lock_init(spa);
611
612	avl_add(&spa_namespace_avl, spa);
613
614	/*
615	 * Set the alternate root, if there is one.
616	 */
617	if (altroot) {
618		spa->spa_root = spa_strdup(altroot);
619		spa_active_count++;
620	}
621
622	/*
623	 * Every pool starts with the default cachefile
624	 */
625	list_create(&spa->spa_config_list, sizeof (spa_config_dirent_t),
626	    offsetof(spa_config_dirent_t, scd_link));
627
628	dp = kmem_zalloc(sizeof (spa_config_dirent_t), KM_SLEEP);
629	dp->scd_path = altroot ? NULL : spa_strdup(spa_config_path);
630	list_insert_head(&spa->spa_config_list, dp);
631
632	VERIFY(nvlist_alloc(&spa->spa_load_info, NV_UNIQUE_NAME,
633	    KM_SLEEP) == 0);
634
635	if (config != NULL) {
636		nvlist_t *features;
637
638		if (nvlist_lookup_nvlist(config, ZPOOL_CONFIG_FEATURES_FOR_READ,
639		    &features) == 0) {
640			VERIFY(nvlist_dup(features, &spa->spa_label_features,
641			    0) == 0);
642		}
643
644		VERIFY(nvlist_dup(config, &spa->spa_config, 0) == 0);
645	}
646
647	if (spa->spa_label_features == NULL) {
648		VERIFY(nvlist_alloc(&spa->spa_label_features, NV_UNIQUE_NAME,
649		    KM_SLEEP) == 0);
650	}
651
652	spa->spa_iokstat = kstat_create("zfs", 0, name,
653	    "disk", KSTAT_TYPE_IO, 1, 0);
654	if (spa->spa_iokstat) {
655		spa->spa_iokstat->ks_lock = &spa->spa_iokstat_lock;
656		kstat_install(spa->spa_iokstat);
657	}
658
659	spa->spa_debug = ((zfs_flags & ZFS_DEBUG_SPA) != 0);
660
661	spa->spa_min_ashift = INT_MAX;
662	spa->spa_max_ashift = 0;
663
664	/*
665	 * As a pool is being created, treat all features as disabled by
666	 * setting SPA_FEATURE_DISABLED for all entries in the feature
667	 * refcount cache.
668	 */
669	for (int i = 0; i < SPA_FEATURES; i++) {
670		spa->spa_feat_refcount_cache[i] = SPA_FEATURE_DISABLED;
671	}
672
673	return (spa);
674}
675
676/*
677 * Removes a spa_t from the namespace, freeing up any memory used.  Requires
678 * spa_namespace_lock.  This is called only after the spa_t has been closed and
679 * deactivated.
680 */
681void
682spa_remove(spa_t *spa)
683{
684	spa_config_dirent_t *dp;
685
686	ASSERT(MUTEX_HELD(&spa_namespace_lock));
687	ASSERT(spa->spa_state == POOL_STATE_UNINITIALIZED);
688	ASSERT3U(refcount_count(&spa->spa_refcount), ==, 0);
689
690	nvlist_free(spa->spa_config_splitting);
691
692	avl_remove(&spa_namespace_avl, spa);
693	cv_broadcast(&spa_namespace_cv);
694
695	if (spa->spa_root) {
696		spa_strfree(spa->spa_root);
697		spa_active_count--;
698	}
699
700	while ((dp = list_head(&spa->spa_config_list)) != NULL) {
701		list_remove(&spa->spa_config_list, dp);
702		if (dp->scd_path != NULL)
703			spa_strfree(dp->scd_path);
704		kmem_free(dp, sizeof (spa_config_dirent_t));
705	}
706
707	list_destroy(&spa->spa_config_list);
708
709	nvlist_free(spa->spa_label_features);
710	nvlist_free(spa->spa_load_info);
711	spa_config_set(spa, NULL);
712
713	mutex_enter(&cpu_lock);
714	if (spa->spa_deadman_cycid != CYCLIC_NONE)
715		cyclic_remove(spa->spa_deadman_cycid);
716	mutex_exit(&cpu_lock);
717	spa->spa_deadman_cycid = CYCLIC_NONE;
718
719	refcount_destroy(&spa->spa_refcount);
720
721	spa_config_lock_destroy(spa);
722
723	kstat_delete(spa->spa_iokstat);
724	spa->spa_iokstat = NULL;
725
726	for (int t = 0; t < TXG_SIZE; t++)
727		bplist_destroy(&spa->spa_free_bplist[t]);
728
729	zio_checksum_templates_free(spa);
730
731	cv_destroy(&spa->spa_async_cv);
732	cv_destroy(&spa->spa_evicting_os_cv);
733	cv_destroy(&spa->spa_proc_cv);
734	cv_destroy(&spa->spa_scrub_io_cv);
735	cv_destroy(&spa->spa_suspend_cv);
736
737	mutex_destroy(&spa->spa_async_lock);
738	mutex_destroy(&spa->spa_errlist_lock);
739	mutex_destroy(&spa->spa_errlog_lock);
740	mutex_destroy(&spa->spa_evicting_os_lock);
741	mutex_destroy(&spa->spa_history_lock);
742	mutex_destroy(&spa->spa_proc_lock);
743	mutex_destroy(&spa->spa_props_lock);
744	mutex_destroy(&spa->spa_cksum_tmpls_lock);
745	mutex_destroy(&spa->spa_scrub_lock);
746	mutex_destroy(&spa->spa_suspend_lock);
747	mutex_destroy(&spa->spa_vdev_top_lock);
748	mutex_destroy(&spa->spa_iokstat_lock);
749
750	kmem_free(spa, sizeof (spa_t));
751}
752
753/*
754 * Given a pool, return the next pool in the namespace, or NULL if there is
755 * none.  If 'prev' is NULL, return the first pool.
756 */
757spa_t *
758spa_next(spa_t *prev)
759{
760	ASSERT(MUTEX_HELD(&spa_namespace_lock));
761
762	if (prev)
763		return (AVL_NEXT(&spa_namespace_avl, prev));
764	else
765		return (avl_first(&spa_namespace_avl));
766}
767
768/*
769 * ==========================================================================
770 * SPA refcount functions
771 * ==========================================================================
772 */
773
774/*
775 * Add a reference to the given spa_t.  Must have at least one reference, or
776 * have the namespace lock held.
777 */
778void
779spa_open_ref(spa_t *spa, void *tag)
780{
781	ASSERT(refcount_count(&spa->spa_refcount) >= spa->spa_minref ||
782	    MUTEX_HELD(&spa_namespace_lock));
783	(void) refcount_add(&spa->spa_refcount, tag);
784}
785
786/*
787 * Remove a reference to the given spa_t.  Must have at least one reference, or
788 * have the namespace lock held.
789 */
790void
791spa_close(spa_t *spa, void *tag)
792{
793	ASSERT(refcount_count(&spa->spa_refcount) > spa->spa_minref ||
794	    MUTEX_HELD(&spa_namespace_lock));
795	(void) refcount_remove(&spa->spa_refcount, tag);
796}
797
798/*
799 * Remove a reference to the given spa_t held by a dsl dir that is
800 * being asynchronously released.  Async releases occur from a taskq
801 * performing eviction of dsl datasets and dirs.  The namespace lock
802 * isn't held and the hold by the object being evicted may contribute to
803 * spa_minref (e.g. dataset or directory released during pool export),
804 * so the asserts in spa_close() do not apply.
805 */
806void
807spa_async_close(spa_t *spa, void *tag)
808{
809	(void) refcount_remove(&spa->spa_refcount, tag);
810}
811
812/*
813 * Check to see if the spa refcount is zero.  Must be called with
814 * spa_namespace_lock held.  We really compare against spa_minref, which is the
815 * number of references acquired when opening a pool
816 */
817boolean_t
818spa_refcount_zero(spa_t *spa)
819{
820	ASSERT(MUTEX_HELD(&spa_namespace_lock));
821
822	return (refcount_count(&spa->spa_refcount) == spa->spa_minref);
823}
824
825/*
826 * ==========================================================================
827 * SPA spare and l2cache tracking
828 * ==========================================================================
829 */
830
831/*
832 * Hot spares and cache devices are tracked using the same code below,
833 * for 'auxiliary' devices.
834 */
835
836typedef struct spa_aux {
837	uint64_t	aux_guid;
838	uint64_t	aux_pool;
839	avl_node_t	aux_avl;
840	int		aux_count;
841} spa_aux_t;
842
843static int
844spa_aux_compare(const void *a, const void *b)
845{
846	const spa_aux_t *sa = a;
847	const spa_aux_t *sb = b;
848
849	if (sa->aux_guid < sb->aux_guid)
850		return (-1);
851	else if (sa->aux_guid > sb->aux_guid)
852		return (1);
853	else
854		return (0);
855}
856
857void
858spa_aux_add(vdev_t *vd, avl_tree_t *avl)
859{
860	avl_index_t where;
861	spa_aux_t search;
862	spa_aux_t *aux;
863
864	search.aux_guid = vd->vdev_guid;
865	if ((aux = avl_find(avl, &search, &where)) != NULL) {
866		aux->aux_count++;
867	} else {
868		aux = kmem_zalloc(sizeof (spa_aux_t), KM_SLEEP);
869		aux->aux_guid = vd->vdev_guid;
870		aux->aux_count = 1;
871		avl_insert(avl, aux, where);
872	}
873}
874
875void
876spa_aux_remove(vdev_t *vd, avl_tree_t *avl)
877{
878	spa_aux_t search;
879	spa_aux_t *aux;
880	avl_index_t where;
881
882	search.aux_guid = vd->vdev_guid;
883	aux = avl_find(avl, &search, &where);
884
885	ASSERT(aux != NULL);
886
887	if (--aux->aux_count == 0) {
888		avl_remove(avl, aux);
889		kmem_free(aux, sizeof (spa_aux_t));
890	} else if (aux->aux_pool == spa_guid(vd->vdev_spa)) {
891		aux->aux_pool = 0ULL;
892	}
893}
894
895boolean_t
896spa_aux_exists(uint64_t guid, uint64_t *pool, int *refcnt, avl_tree_t *avl)
897{
898	spa_aux_t search, *found;
899
900	search.aux_guid = guid;
901	found = avl_find(avl, &search, NULL);
902
903	if (pool) {
904		if (found)
905			*pool = found->aux_pool;
906		else
907			*pool = 0ULL;
908	}
909
910	if (refcnt) {
911		if (found)
912			*refcnt = found->aux_count;
913		else
914			*refcnt = 0;
915	}
916
917	return (found != NULL);
918}
919
920void
921spa_aux_activate(vdev_t *vd, avl_tree_t *avl)
922{
923	spa_aux_t search, *found;
924	avl_index_t where;
925
926	search.aux_guid = vd->vdev_guid;
927	found = avl_find(avl, &search, &where);
928	ASSERT(found != NULL);
929	ASSERT(found->aux_pool == 0ULL);
930
931	found->aux_pool = spa_guid(vd->vdev_spa);
932}
933
934/*
935 * Spares are tracked globally due to the following constraints:
936 *
937 * 	- A spare may be part of multiple pools.
938 * 	- A spare may be added to a pool even if it's actively in use within
939 *	  another pool.
940 * 	- A spare in use in any pool can only be the source of a replacement if
941 *	  the target is a spare in the same pool.
942 *
943 * We keep track of all spares on the system through the use of a reference
944 * counted AVL tree.  When a vdev is added as a spare, or used as a replacement
945 * spare, then we bump the reference count in the AVL tree.  In addition, we set
946 * the 'vdev_isspare' member to indicate that the device is a spare (active or
947 * inactive).  When a spare is made active (used to replace a device in the
948 * pool), we also keep track of which pool its been made a part of.
949 *
950 * The 'spa_spare_lock' protects the AVL tree.  These functions are normally
951 * called under the spa_namespace lock as part of vdev reconfiguration.  The
952 * separate spare lock exists for the status query path, which does not need to
953 * be completely consistent with respect to other vdev configuration changes.
954 */
955
956static int
957spa_spare_compare(const void *a, const void *b)
958{
959	return (spa_aux_compare(a, b));
960}
961
962void
963spa_spare_add(vdev_t *vd)
964{
965	mutex_enter(&spa_spare_lock);
966	ASSERT(!vd->vdev_isspare);
967	spa_aux_add(vd, &spa_spare_avl);
968	vd->vdev_isspare = B_TRUE;
969	mutex_exit(&spa_spare_lock);
970}
971
972void
973spa_spare_remove(vdev_t *vd)
974{
975	mutex_enter(&spa_spare_lock);
976	ASSERT(vd->vdev_isspare);
977	spa_aux_remove(vd, &spa_spare_avl);
978	vd->vdev_isspare = B_FALSE;
979	mutex_exit(&spa_spare_lock);
980}
981
982boolean_t
983spa_spare_exists(uint64_t guid, uint64_t *pool, int *refcnt)
984{
985	boolean_t found;
986
987	mutex_enter(&spa_spare_lock);
988	found = spa_aux_exists(guid, pool, refcnt, &spa_spare_avl);
989	mutex_exit(&spa_spare_lock);
990
991	return (found);
992}
993
994void
995spa_spare_activate(vdev_t *vd)
996{
997	mutex_enter(&spa_spare_lock);
998	ASSERT(vd->vdev_isspare);
999	spa_aux_activate(vd, &spa_spare_avl);
1000	mutex_exit(&spa_spare_lock);
1001}
1002
1003/*
1004 * Level 2 ARC devices are tracked globally for the same reasons as spares.
1005 * Cache devices currently only support one pool per cache device, and so
1006 * for these devices the aux reference count is currently unused beyond 1.
1007 */
1008
1009static int
1010spa_l2cache_compare(const void *a, const void *b)
1011{
1012	return (spa_aux_compare(a, b));
1013}
1014
1015void
1016spa_l2cache_add(vdev_t *vd)
1017{
1018	mutex_enter(&spa_l2cache_lock);
1019	ASSERT(!vd->vdev_isl2cache);
1020	spa_aux_add(vd, &spa_l2cache_avl);
1021	vd->vdev_isl2cache = B_TRUE;
1022	mutex_exit(&spa_l2cache_lock);
1023}
1024
1025void
1026spa_l2cache_remove(vdev_t *vd)
1027{
1028	mutex_enter(&spa_l2cache_lock);
1029	ASSERT(vd->vdev_isl2cache);
1030	spa_aux_remove(vd, &spa_l2cache_avl);
1031	vd->vdev_isl2cache = B_FALSE;
1032	mutex_exit(&spa_l2cache_lock);
1033}
1034
1035boolean_t
1036spa_l2cache_exists(uint64_t guid, uint64_t *pool)
1037{
1038	boolean_t found;
1039
1040	mutex_enter(&spa_l2cache_lock);
1041	found = spa_aux_exists(guid, pool, NULL, &spa_l2cache_avl);
1042	mutex_exit(&spa_l2cache_lock);
1043
1044	return (found);
1045}
1046
1047void
1048spa_l2cache_activate(vdev_t *vd)
1049{
1050	mutex_enter(&spa_l2cache_lock);
1051	ASSERT(vd->vdev_isl2cache);
1052	spa_aux_activate(vd, &spa_l2cache_avl);
1053	mutex_exit(&spa_l2cache_lock);
1054}
1055
1056/*
1057 * ==========================================================================
1058 * SPA vdev locking
1059 * ==========================================================================
1060 */
1061
1062/*
1063 * Lock the given spa_t for the purpose of adding or removing a vdev.
1064 * Grabs the global spa_namespace_lock plus the spa config lock for writing.
1065 * It returns the next transaction group for the spa_t.
1066 */
1067uint64_t
1068spa_vdev_enter(spa_t *spa)
1069{
1070	mutex_enter(&spa->spa_vdev_top_lock);
1071	mutex_enter(&spa_namespace_lock);
1072	return (spa_vdev_config_enter(spa));
1073}
1074
1075/*
1076 * Internal implementation for spa_vdev_enter().  Used when a vdev
1077 * operation requires multiple syncs (i.e. removing a device) while
1078 * keeping the spa_namespace_lock held.
1079 */
1080uint64_t
1081spa_vdev_config_enter(spa_t *spa)
1082{
1083	ASSERT(MUTEX_HELD(&spa_namespace_lock));
1084
1085	spa_config_enter(spa, SCL_ALL, spa, RW_WRITER);
1086
1087	return (spa_last_synced_txg(spa) + 1);
1088}
1089
1090/*
1091 * Used in combination with spa_vdev_config_enter() to allow the syncing
1092 * of multiple transactions without releasing the spa_namespace_lock.
1093 */
1094void
1095spa_vdev_config_exit(spa_t *spa, vdev_t *vd, uint64_t txg, int error, char *tag)
1096{
1097	ASSERT(MUTEX_HELD(&spa_namespace_lock));
1098
1099	int config_changed = B_FALSE;
1100
1101	ASSERT(txg > spa_last_synced_txg(spa));
1102
1103	spa->spa_pending_vdev = NULL;
1104
1105	/*
1106	 * Reassess the DTLs.
1107	 */
1108	vdev_dtl_reassess(spa->spa_root_vdev, 0, 0, B_FALSE);
1109
1110	if (error == 0 && !list_is_empty(&spa->spa_config_dirty_list)) {
1111		config_changed = B_TRUE;
1112		spa->spa_config_generation++;
1113	}
1114
1115	/*
1116	 * Verify the metaslab classes.
1117	 */
1118	ASSERT(metaslab_class_validate(spa_normal_class(spa)) == 0);
1119	ASSERT(metaslab_class_validate(spa_log_class(spa)) == 0);
1120
1121	spa_config_exit(spa, SCL_ALL, spa);
1122
1123	/*
1124	 * Panic the system if the specified tag requires it.  This
1125	 * is useful for ensuring that configurations are updated
1126	 * transactionally.
1127	 */
1128	if (zio_injection_enabled)
1129		zio_handle_panic_injection(spa, tag, 0);
1130
1131	/*
1132	 * Note: this txg_wait_synced() is important because it ensures
1133	 * that there won't be more than one config change per txg.
1134	 * This allows us to use the txg as the generation number.
1135	 */
1136	if (error == 0)
1137		txg_wait_synced(spa->spa_dsl_pool, txg);
1138
1139	if (vd != NULL) {
1140		ASSERT(!vd->vdev_detached || vd->vdev_dtl_sm == NULL);
1141		spa_config_enter(spa, SCL_ALL, spa, RW_WRITER);
1142		vdev_free(vd);
1143		spa_config_exit(spa, SCL_ALL, spa);
1144	}
1145
1146	/*
1147	 * If the config changed, update the config cache.
1148	 */
1149	if (config_changed)
1150		spa_config_sync(spa, B_FALSE, B_TRUE);
1151}
1152
1153/*
1154 * Unlock the spa_t after adding or removing a vdev.  Besides undoing the
1155 * locking of spa_vdev_enter(), we also want make sure the transactions have
1156 * synced to disk, and then update the global configuration cache with the new
1157 * information.
1158 */
1159int
1160spa_vdev_exit(spa_t *spa, vdev_t *vd, uint64_t txg, int error)
1161{
1162	spa_vdev_config_exit(spa, vd, txg, error, FTAG);
1163	mutex_exit(&spa_namespace_lock);
1164	mutex_exit(&spa->spa_vdev_top_lock);
1165
1166	return (error);
1167}
1168
1169/*
1170 * Lock the given spa_t for the purpose of changing vdev state.
1171 */
1172void
1173spa_vdev_state_enter(spa_t *spa, int oplocks)
1174{
1175	int locks = SCL_STATE_ALL | oplocks;
1176
1177	/*
1178	 * Root pools may need to read of the underlying devfs filesystem
1179	 * when opening up a vdev.  Unfortunately if we're holding the
1180	 * SCL_ZIO lock it will result in a deadlock when we try to issue
1181	 * the read from the root filesystem.  Instead we "prefetch"
1182	 * the associated vnodes that we need prior to opening the
1183	 * underlying devices and cache them so that we can prevent
1184	 * any I/O when we are doing the actual open.
1185	 */
1186	if (spa_is_root(spa)) {
1187		int low = locks & ~(SCL_ZIO - 1);
1188		int high = locks & ~low;
1189
1190		spa_config_enter(spa, high, spa, RW_WRITER);
1191		vdev_hold(spa->spa_root_vdev);
1192		spa_config_enter(spa, low, spa, RW_WRITER);
1193	} else {
1194		spa_config_enter(spa, locks, spa, RW_WRITER);
1195	}
1196	spa->spa_vdev_locks = locks;
1197}
1198
1199int
1200spa_vdev_state_exit(spa_t *spa, vdev_t *vd, int error)
1201{
1202	boolean_t config_changed = B_FALSE;
1203
1204	if (vd != NULL || error == 0)
1205		vdev_dtl_reassess(vd ? vd->vdev_top : spa->spa_root_vdev,
1206		    0, 0, B_FALSE);
1207
1208	if (vd != NULL) {
1209		vdev_state_dirty(vd->vdev_top);
1210		config_changed = B_TRUE;
1211		spa->spa_config_generation++;
1212	}
1213
1214	if (spa_is_root(spa))
1215		vdev_rele(spa->spa_root_vdev);
1216
1217	ASSERT3U(spa->spa_vdev_locks, >=, SCL_STATE_ALL);
1218	spa_config_exit(spa, spa->spa_vdev_locks, spa);
1219
1220	/*
1221	 * If anything changed, wait for it to sync.  This ensures that,
1222	 * from the system administrator's perspective, zpool(1M) commands
1223	 * are synchronous.  This is important for things like zpool offline:
1224	 * when the command completes, you expect no further I/O from ZFS.
1225	 */
1226	if (vd != NULL)
1227		txg_wait_synced(spa->spa_dsl_pool, 0);
1228
1229	/*
1230	 * If the config changed, update the config cache.
1231	 */
1232	if (config_changed) {
1233		mutex_enter(&spa_namespace_lock);
1234		spa_config_sync(spa, B_FALSE, B_TRUE);
1235		mutex_exit(&spa_namespace_lock);
1236	}
1237
1238	return (error);
1239}
1240
1241/*
1242 * ==========================================================================
1243 * Miscellaneous functions
1244 * ==========================================================================
1245 */
1246
1247void
1248spa_activate_mos_feature(spa_t *spa, const char *feature, dmu_tx_t *tx)
1249{
1250	if (!nvlist_exists(spa->spa_label_features, feature)) {
1251		fnvlist_add_boolean(spa->spa_label_features, feature);
1252		/*
1253		 * When we are creating the pool (tx_txg==TXG_INITIAL), we can't
1254		 * dirty the vdev config because lock SCL_CONFIG is not held.
1255		 * Thankfully, in this case we don't need to dirty the config
1256		 * because it will be written out anyway when we finish
1257		 * creating the pool.
1258		 */
1259		if (tx->tx_txg != TXG_INITIAL)
1260			vdev_config_dirty(spa->spa_root_vdev);
1261	}
1262}
1263
1264void
1265spa_deactivate_mos_feature(spa_t *spa, const char *feature)
1266{
1267	if (nvlist_remove_all(spa->spa_label_features, feature) == 0)
1268		vdev_config_dirty(spa->spa_root_vdev);
1269}
1270
1271/*
1272 * Rename a spa_t.
1273 */
1274int
1275spa_rename(const char *name, const char *newname)
1276{
1277	spa_t *spa;
1278	int err;
1279
1280	/*
1281	 * Lookup the spa_t and grab the config lock for writing.  We need to
1282	 * actually open the pool so that we can sync out the necessary labels.
1283	 * It's OK to call spa_open() with the namespace lock held because we
1284	 * allow recursive calls for other reasons.
1285	 */
1286	mutex_enter(&spa_namespace_lock);
1287	if ((err = spa_open(name, &spa, FTAG)) != 0) {
1288		mutex_exit(&spa_namespace_lock);
1289		return (err);
1290	}
1291
1292	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
1293
1294	avl_remove(&spa_namespace_avl, spa);
1295	(void) strlcpy(spa->spa_name, newname, sizeof (spa->spa_name));
1296	avl_add(&spa_namespace_avl, spa);
1297
1298	/*
1299	 * Sync all labels to disk with the new names by marking the root vdev
1300	 * dirty and waiting for it to sync.  It will pick up the new pool name
1301	 * during the sync.
1302	 */
1303	vdev_config_dirty(spa->spa_root_vdev);
1304
1305	spa_config_exit(spa, SCL_ALL, FTAG);
1306
1307	txg_wait_synced(spa->spa_dsl_pool, 0);
1308
1309	/*
1310	 * Sync the updated config cache.
1311	 */
1312	spa_config_sync(spa, B_FALSE, B_TRUE);
1313
1314	spa_close(spa, FTAG);
1315
1316	mutex_exit(&spa_namespace_lock);
1317
1318	return (0);
1319}
1320
1321/*
1322 * Return the spa_t associated with given pool_guid, if it exists.  If
1323 * device_guid is non-zero, determine whether the pool exists *and* contains
1324 * a device with the specified device_guid.
1325 */
1326spa_t *
1327spa_by_guid(uint64_t pool_guid, uint64_t device_guid)
1328{
1329	spa_t *spa;
1330	avl_tree_t *t = &spa_namespace_avl;
1331
1332	ASSERT(MUTEX_HELD(&spa_namespace_lock));
1333
1334	for (spa = avl_first(t); spa != NULL; spa = AVL_NEXT(t, spa)) {
1335		if (spa->spa_state == POOL_STATE_UNINITIALIZED)
1336			continue;
1337		if (spa->spa_root_vdev == NULL)
1338			continue;
1339		if (spa_guid(spa) == pool_guid) {
1340			if (device_guid == 0)
1341				break;
1342
1343			if (vdev_lookup_by_guid(spa->spa_root_vdev,
1344			    device_guid) != NULL)
1345				break;
1346
1347			/*
1348			 * Check any devices we may be in the process of adding.
1349			 */
1350			if (spa->spa_pending_vdev) {
1351				if (vdev_lookup_by_guid(spa->spa_pending_vdev,
1352				    device_guid) != NULL)
1353					break;
1354			}
1355		}
1356	}
1357
1358	return (spa);
1359}
1360
1361/*
1362 * Determine whether a pool with the given pool_guid exists.
1363 */
1364boolean_t
1365spa_guid_exists(uint64_t pool_guid, uint64_t device_guid)
1366{
1367	return (spa_by_guid(pool_guid, device_guid) != NULL);
1368}
1369
1370char *
1371spa_strdup(const char *s)
1372{
1373	size_t len;
1374	char *new;
1375
1376	len = strlen(s);
1377	new = kmem_alloc(len + 1, KM_SLEEP);
1378	bcopy(s, new, len);
1379	new[len] = '\0';
1380
1381	return (new);
1382}
1383
1384void
1385spa_strfree(char *s)
1386{
1387	kmem_free(s, strlen(s) + 1);
1388}
1389
1390uint64_t
1391spa_get_random(uint64_t range)
1392{
1393	uint64_t r;
1394
1395	ASSERT(range != 0);
1396
1397	(void) random_get_pseudo_bytes((void *)&r, sizeof (uint64_t));
1398
1399	return (r % range);
1400}
1401
1402uint64_t
1403spa_generate_guid(spa_t *spa)
1404{
1405	uint64_t guid = spa_get_random(-1ULL);
1406
1407	if (spa != NULL) {
1408		while (guid == 0 || spa_guid_exists(spa_guid(spa), guid))
1409			guid = spa_get_random(-1ULL);
1410	} else {
1411		while (guid == 0 || spa_guid_exists(guid, 0))
1412			guid = spa_get_random(-1ULL);
1413	}
1414
1415	return (guid);
1416}
1417
1418void
1419snprintf_blkptr(char *buf, size_t buflen, const blkptr_t *bp)
1420{
1421	char type[256];
1422	char *checksum = NULL;
1423	char *compress = NULL;
1424
1425	if (bp != NULL) {
1426		if (BP_GET_TYPE(bp) & DMU_OT_NEWTYPE) {
1427			dmu_object_byteswap_t bswap =
1428			    DMU_OT_BYTESWAP(BP_GET_TYPE(bp));
1429			(void) snprintf(type, sizeof (type), "bswap %s %s",
1430			    DMU_OT_IS_METADATA(BP_GET_TYPE(bp)) ?
1431			    "metadata" : "data",
1432			    dmu_ot_byteswap[bswap].ob_name);
1433		} else {
1434			(void) strlcpy(type, dmu_ot[BP_GET_TYPE(bp)].ot_name,
1435			    sizeof (type));
1436		}
1437		if (!BP_IS_EMBEDDED(bp)) {
1438			checksum =
1439			    zio_checksum_table[BP_GET_CHECKSUM(bp)].ci_name;
1440		}
1441		compress = zio_compress_table[BP_GET_COMPRESS(bp)].ci_name;
1442	}
1443
1444	SNPRINTF_BLKPTR(snprintf, ' ', buf, buflen, bp, type, checksum,
1445	    compress);
1446}
1447
1448void
1449spa_freeze(spa_t *spa)
1450{
1451	uint64_t freeze_txg = 0;
1452
1453	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
1454	if (spa->spa_freeze_txg == UINT64_MAX) {
1455		freeze_txg = spa_last_synced_txg(spa) + TXG_SIZE;
1456		spa->spa_freeze_txg = freeze_txg;
1457	}
1458	spa_config_exit(spa, SCL_ALL, FTAG);
1459	if (freeze_txg != 0)
1460		txg_wait_synced(spa_get_dsl(spa), freeze_txg);
1461}
1462
1463void
1464zfs_panic_recover(const char *fmt, ...)
1465{
1466	va_list adx;
1467
1468	va_start(adx, fmt);
1469	vcmn_err(zfs_recover ? CE_WARN : CE_PANIC, fmt, adx);
1470	va_end(adx);
1471}
1472
1473/*
1474 * This is a stripped-down version of strtoull, suitable only for converting
1475 * lowercase hexadecimal numbers that don't overflow.
1476 */
1477uint64_t
1478strtonum(const char *str, char **nptr)
1479{
1480	uint64_t val = 0;
1481	char c;
1482	int digit;
1483
1484	while ((c = *str) != '\0') {
1485		if (c >= '0' && c <= '9')
1486			digit = c - '0';
1487		else if (c >= 'a' && c <= 'f')
1488			digit = 10 + c - 'a';
1489		else
1490			break;
1491
1492		val *= 16;
1493		val += digit;
1494
1495		str++;
1496	}
1497
1498	if (nptr)
1499		*nptr = (char *)str;
1500
1501	return (val);
1502}
1503
1504/*
1505 * ==========================================================================
1506 * Accessor functions
1507 * ==========================================================================
1508 */
1509
1510boolean_t
1511spa_shutting_down(spa_t *spa)
1512{
1513	return (spa->spa_async_suspended);
1514}
1515
1516dsl_pool_t *
1517spa_get_dsl(spa_t *spa)
1518{
1519	return (spa->spa_dsl_pool);
1520}
1521
1522boolean_t
1523spa_is_initializing(spa_t *spa)
1524{
1525	return (spa->spa_is_initializing);
1526}
1527
1528blkptr_t *
1529spa_get_rootblkptr(spa_t *spa)
1530{
1531	return (&spa->spa_ubsync.ub_rootbp);
1532}
1533
1534void
1535spa_set_rootblkptr(spa_t *spa, const blkptr_t *bp)
1536{
1537	spa->spa_uberblock.ub_rootbp = *bp;
1538}
1539
1540void
1541spa_altroot(spa_t *spa, char *buf, size_t buflen)
1542{
1543	if (spa->spa_root == NULL)
1544		buf[0] = '\0';
1545	else
1546		(void) strncpy(buf, spa->spa_root, buflen);
1547}
1548
1549int
1550spa_sync_pass(spa_t *spa)
1551{
1552	return (spa->spa_sync_pass);
1553}
1554
1555char *
1556spa_name(spa_t *spa)
1557{
1558	return (spa->spa_name);
1559}
1560
1561uint64_t
1562spa_guid(spa_t *spa)
1563{
1564	dsl_pool_t *dp = spa_get_dsl(spa);
1565	uint64_t guid;
1566
1567	/*
1568	 * If we fail to parse the config during spa_load(), we can go through
1569	 * the error path (which posts an ereport) and end up here with no root
1570	 * vdev.  We stash the original pool guid in 'spa_config_guid' to handle
1571	 * this case.
1572	 */
1573	if (spa->spa_root_vdev == NULL)
1574		return (spa->spa_config_guid);
1575
1576	guid = spa->spa_last_synced_guid != 0 ?
1577	    spa->spa_last_synced_guid : spa->spa_root_vdev->vdev_guid;
1578
1579	/*
1580	 * Return the most recently synced out guid unless we're
1581	 * in syncing context.
1582	 */
1583	if (dp && dsl_pool_sync_context(dp))
1584		return (spa->spa_root_vdev->vdev_guid);
1585	else
1586		return (guid);
1587}
1588
1589uint64_t
1590spa_load_guid(spa_t *spa)
1591{
1592	/*
1593	 * This is a GUID that exists solely as a reference for the
1594	 * purposes of the arc.  It is generated at load time, and
1595	 * is never written to persistent storage.
1596	 */
1597	return (spa->spa_load_guid);
1598}
1599
1600uint64_t
1601spa_last_synced_txg(spa_t *spa)
1602{
1603	return (spa->spa_ubsync.ub_txg);
1604}
1605
1606uint64_t
1607spa_first_txg(spa_t *spa)
1608{
1609	return (spa->spa_first_txg);
1610}
1611
1612uint64_t
1613spa_syncing_txg(spa_t *spa)
1614{
1615	return (spa->spa_syncing_txg);
1616}
1617
1618pool_state_t
1619spa_state(spa_t *spa)
1620{
1621	return (spa->spa_state);
1622}
1623
1624spa_load_state_t
1625spa_load_state(spa_t *spa)
1626{
1627	return (spa->spa_load_state);
1628}
1629
1630uint64_t
1631spa_freeze_txg(spa_t *spa)
1632{
1633	return (spa->spa_freeze_txg);
1634}
1635
1636/* ARGSUSED */
1637uint64_t
1638spa_get_asize(spa_t *spa, uint64_t lsize)
1639{
1640	return (lsize * spa_asize_inflation);
1641}
1642
1643/*
1644 * Return the amount of slop space in bytes.  It is 1/32 of the pool (3.2%),
1645 * or at least 128MB, unless that would cause it to be more than half the
1646 * pool size.
1647 *
1648 * See the comment above spa_slop_shift for details.
1649 */
1650uint64_t
1651spa_get_slop_space(spa_t *spa)
1652{
1653	uint64_t space = spa_get_dspace(spa);
1654	return (MAX(space >> spa_slop_shift, MIN(space >> 1, spa_min_slop)));
1655}
1656
1657uint64_t
1658spa_get_dspace(spa_t *spa)
1659{
1660	return (spa->spa_dspace);
1661}
1662
1663void
1664spa_update_dspace(spa_t *spa)
1665{
1666	spa->spa_dspace = metaslab_class_get_dspace(spa_normal_class(spa)) +
1667	    ddt_get_dedup_dspace(spa);
1668}
1669
1670/*
1671 * Return the failure mode that has been set to this pool. The default
1672 * behavior will be to block all I/Os when a complete failure occurs.
1673 */
1674uint8_t
1675spa_get_failmode(spa_t *spa)
1676{
1677	return (spa->spa_failmode);
1678}
1679
1680boolean_t
1681spa_suspended(spa_t *spa)
1682{
1683	return (spa->spa_suspended);
1684}
1685
1686uint64_t
1687spa_version(spa_t *spa)
1688{
1689	return (spa->spa_ubsync.ub_version);
1690}
1691
1692boolean_t
1693spa_deflate(spa_t *spa)
1694{
1695	return (spa->spa_deflate);
1696}
1697
1698metaslab_class_t *
1699spa_normal_class(spa_t *spa)
1700{
1701	return (spa->spa_normal_class);
1702}
1703
1704metaslab_class_t *
1705spa_log_class(spa_t *spa)
1706{
1707	return (spa->spa_log_class);
1708}
1709
1710void
1711spa_evicting_os_register(spa_t *spa, objset_t *os)
1712{
1713	mutex_enter(&spa->spa_evicting_os_lock);
1714	list_insert_head(&spa->spa_evicting_os_list, os);
1715	mutex_exit(&spa->spa_evicting_os_lock);
1716}
1717
1718void
1719spa_evicting_os_deregister(spa_t *spa, objset_t *os)
1720{
1721	mutex_enter(&spa->spa_evicting_os_lock);
1722	list_remove(&spa->spa_evicting_os_list, os);
1723	cv_broadcast(&spa->spa_evicting_os_cv);
1724	mutex_exit(&spa->spa_evicting_os_lock);
1725}
1726
1727void
1728spa_evicting_os_wait(spa_t *spa)
1729{
1730	mutex_enter(&spa->spa_evicting_os_lock);
1731	while (!list_is_empty(&spa->spa_evicting_os_list))
1732		cv_wait(&spa->spa_evicting_os_cv, &spa->spa_evicting_os_lock);
1733	mutex_exit(&spa->spa_evicting_os_lock);
1734
1735	dmu_buf_user_evict_wait();
1736}
1737
1738int
1739spa_max_replication(spa_t *spa)
1740{
1741	/*
1742	 * As of SPA_VERSION == SPA_VERSION_DITTO_BLOCKS, we are able to
1743	 * handle BPs with more than one DVA allocated.  Set our max
1744	 * replication level accordingly.
1745	 */
1746	if (spa_version(spa) < SPA_VERSION_DITTO_BLOCKS)
1747		return (1);
1748	return (MIN(SPA_DVAS_PER_BP, spa_max_replication_override));
1749}
1750
1751int
1752spa_prev_software_version(spa_t *spa)
1753{
1754	return (spa->spa_prev_software_version);
1755}
1756
1757uint64_t
1758spa_deadman_synctime(spa_t *spa)
1759{
1760	return (spa->spa_deadman_synctime);
1761}
1762
1763uint64_t
1764dva_get_dsize_sync(spa_t *spa, const dva_t *dva)
1765{
1766	uint64_t asize = DVA_GET_ASIZE(dva);
1767	uint64_t dsize = asize;
1768
1769	ASSERT(spa_config_held(spa, SCL_ALL, RW_READER) != 0);
1770
1771	if (asize != 0 && spa->spa_deflate) {
1772		vdev_t *vd = vdev_lookup_top(spa, DVA_GET_VDEV(dva));
1773		dsize = (asize >> SPA_MINBLOCKSHIFT) * vd->vdev_deflate_ratio;
1774	}
1775
1776	return (dsize);
1777}
1778
1779uint64_t
1780bp_get_dsize_sync(spa_t *spa, const blkptr_t *bp)
1781{
1782	uint64_t dsize = 0;
1783
1784	for (int d = 0; d < BP_GET_NDVAS(bp); d++)
1785		dsize += dva_get_dsize_sync(spa, &bp->blk_dva[d]);
1786
1787	return (dsize);
1788}
1789
1790uint64_t
1791bp_get_dsize(spa_t *spa, const blkptr_t *bp)
1792{
1793	uint64_t dsize = 0;
1794
1795	spa_config_enter(spa, SCL_VDEV, FTAG, RW_READER);
1796
1797	for (int d = 0; d < BP_GET_NDVAS(bp); d++)
1798		dsize += dva_get_dsize_sync(spa, &bp->blk_dva[d]);
1799
1800	spa_config_exit(spa, SCL_VDEV, FTAG);
1801
1802	return (dsize);
1803}
1804
1805/*
1806 * ==========================================================================
1807 * Initialization and Termination
1808 * ==========================================================================
1809 */
1810
1811static int
1812spa_name_compare(const void *a1, const void *a2)
1813{
1814	const spa_t *s1 = a1;
1815	const spa_t *s2 = a2;
1816	int s;
1817
1818	s = strcmp(s1->spa_name, s2->spa_name);
1819	if (s > 0)
1820		return (1);
1821	if (s < 0)
1822		return (-1);
1823	return (0);
1824}
1825
1826int
1827spa_busy(void)
1828{
1829	return (spa_active_count);
1830}
1831
1832void
1833spa_boot_init()
1834{
1835	spa_config_load();
1836}
1837
1838void
1839spa_init(int mode)
1840{
1841	mutex_init(&spa_namespace_lock, NULL, MUTEX_DEFAULT, NULL);
1842	mutex_init(&spa_spare_lock, NULL, MUTEX_DEFAULT, NULL);
1843	mutex_init(&spa_l2cache_lock, NULL, MUTEX_DEFAULT, NULL);
1844	cv_init(&spa_namespace_cv, NULL, CV_DEFAULT, NULL);
1845
1846	avl_create(&spa_namespace_avl, spa_name_compare, sizeof (spa_t),
1847	    offsetof(spa_t, spa_avl));
1848
1849	avl_create(&spa_spare_avl, spa_spare_compare, sizeof (spa_aux_t),
1850	    offsetof(spa_aux_t, aux_avl));
1851
1852	avl_create(&spa_l2cache_avl, spa_l2cache_compare, sizeof (spa_aux_t),
1853	    offsetof(spa_aux_t, aux_avl));
1854
1855	spa_mode_global = mode;
1856
1857#ifdef _KERNEL
1858	spa_arch_init();
1859#else
1860	if (spa_mode_global != FREAD && dprintf_find_string("watch")) {
1861		arc_procfd = open("/proc/self/ctl", O_WRONLY);
1862		if (arc_procfd == -1) {
1863			perror("could not enable watchpoints: "
1864			    "opening /proc/self/ctl failed: ");
1865		} else {
1866			arc_watch = B_TRUE;
1867		}
1868	}
1869#endif
1870
1871	refcount_init();
1872	unique_init();
1873	range_tree_init();
1874	zio_init();
1875	dmu_init();
1876	zil_init();
1877	vdev_cache_stat_init();
1878	zfs_prop_init();
1879	zpool_prop_init();
1880	zpool_feature_init();
1881	spa_config_load();
1882	l2arc_start();
1883}
1884
1885void
1886spa_fini(void)
1887{
1888	l2arc_stop();
1889
1890	spa_evict_all();
1891
1892	vdev_cache_stat_fini();
1893	zil_fini();
1894	dmu_fini();
1895	zio_fini();
1896	range_tree_fini();
1897	unique_fini();
1898	refcount_fini();
1899
1900	avl_destroy(&spa_namespace_avl);
1901	avl_destroy(&spa_spare_avl);
1902	avl_destroy(&spa_l2cache_avl);
1903
1904	cv_destroy(&spa_namespace_cv);
1905	mutex_destroy(&spa_namespace_lock);
1906	mutex_destroy(&spa_spare_lock);
1907	mutex_destroy(&spa_l2cache_lock);
1908}
1909
1910/*
1911 * Return whether this pool has slogs. No locking needed.
1912 * It's not a problem if the wrong answer is returned as it's only for
1913 * performance and not correctness
1914 */
1915boolean_t
1916spa_has_slogs(spa_t *spa)
1917{
1918	return (spa->spa_log_class->mc_rotor != NULL);
1919}
1920
1921spa_log_state_t
1922spa_get_log_state(spa_t *spa)
1923{
1924	return (spa->spa_log_state);
1925}
1926
1927void
1928spa_set_log_state(spa_t *spa, spa_log_state_t state)
1929{
1930	spa->spa_log_state = state;
1931}
1932
1933boolean_t
1934spa_is_root(spa_t *spa)
1935{
1936	return (spa->spa_is_root);
1937}
1938
1939boolean_t
1940spa_writeable(spa_t *spa)
1941{
1942	return (!!(spa->spa_mode & FWRITE));
1943}
1944
1945/*
1946 * Returns true if there is a pending sync task in any of the current
1947 * syncing txg, the current quiescing txg, or the current open txg.
1948 */
1949boolean_t
1950spa_has_pending_synctask(spa_t *spa)
1951{
1952	return (!txg_all_lists_empty(&spa->spa_dsl_pool->dp_sync_tasks));
1953}
1954
1955int
1956spa_mode(spa_t *spa)
1957{
1958	return (spa->spa_mode);
1959}
1960
1961uint64_t
1962spa_bootfs(spa_t *spa)
1963{
1964	return (spa->spa_bootfs);
1965}
1966
1967uint64_t
1968spa_delegation(spa_t *spa)
1969{
1970	return (spa->spa_delegation);
1971}
1972
1973objset_t *
1974spa_meta_objset(spa_t *spa)
1975{
1976	return (spa->spa_meta_objset);
1977}
1978
1979enum zio_checksum
1980spa_dedup_checksum(spa_t *spa)
1981{
1982	return (spa->spa_dedup_checksum);
1983}
1984
1985/*
1986 * Reset pool scan stat per scan pass (or reboot).
1987 */
1988void
1989spa_scan_stat_init(spa_t *spa)
1990{
1991	/* data not stored on disk */
1992	spa->spa_scan_pass_start = gethrestime_sec();
1993	spa->spa_scan_pass_exam = 0;
1994	vdev_scan_stat_init(spa->spa_root_vdev);
1995}
1996
1997/*
1998 * Get scan stats for zpool status reports
1999 */
2000int
2001spa_scan_get_stats(spa_t *spa, pool_scan_stat_t *ps)
2002{
2003	dsl_scan_t *scn = spa->spa_dsl_pool ? spa->spa_dsl_pool->dp_scan : NULL;
2004
2005	if (scn == NULL || scn->scn_phys.scn_func == POOL_SCAN_NONE)
2006		return (SET_ERROR(ENOENT));
2007	bzero(ps, sizeof (pool_scan_stat_t));
2008
2009	/* data stored on disk */
2010	ps->pss_func = scn->scn_phys.scn_func;
2011	ps->pss_start_time = scn->scn_phys.scn_start_time;
2012	ps->pss_end_time = scn->scn_phys.scn_end_time;
2013	ps->pss_to_examine = scn->scn_phys.scn_to_examine;
2014	ps->pss_examined = scn->scn_phys.scn_examined;
2015	ps->pss_to_process = scn->scn_phys.scn_to_process;
2016	ps->pss_processed = scn->scn_phys.scn_processed;
2017	ps->pss_errors = scn->scn_phys.scn_errors;
2018	ps->pss_state = scn->scn_phys.scn_state;
2019
2020	/* data not stored on disk */
2021	ps->pss_pass_start = spa->spa_scan_pass_start;
2022	ps->pss_pass_exam = spa->spa_scan_pass_exam;
2023
2024	return (0);
2025}
2026
2027boolean_t
2028spa_debug_enabled(spa_t *spa)
2029{
2030	return (spa->spa_debug);
2031}
2032
2033int
2034spa_maxblocksize(spa_t *spa)
2035{
2036	if (spa_feature_is_enabled(spa, SPA_FEATURE_LARGE_BLOCKS))
2037		return (SPA_MAXBLOCKSIZE);
2038	else
2039		return (SPA_OLD_MAXBLOCKSIZE);
2040}
2041