xref: /titanic_51/usr/src/uts/common/fs/zfs/spa_misc.c (revision e503abb729687d1a36b95ed2794f54452189c858)
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, 2014 by Delphix. All rights reserved.
24  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
25  */
26 
27 #include <sys/zfs_context.h>
28 #include <sys/spa_impl.h>
29 #include <sys/spa_boot.h>
30 #include <sys/zio.h>
31 #include <sys/zio_checksum.h>
32 #include <sys/zio_compress.h>
33 #include <sys/dmu.h>
34 #include <sys/dmu_tx.h>
35 #include <sys/zap.h>
36 #include <sys/zil.h>
37 #include <sys/vdev_impl.h>
38 #include <sys/metaslab.h>
39 #include <sys/uberblock_impl.h>
40 #include <sys/txg.h>
41 #include <sys/avl.h>
42 #include <sys/unique.h>
43 #include <sys/dsl_pool.h>
44 #include <sys/dsl_dir.h>
45 #include <sys/dsl_prop.h>
46 #include <sys/dsl_scan.h>
47 #include <sys/fs/zfs.h>
48 #include <sys/metaslab_impl.h>
49 #include <sys/arc.h>
50 #include <sys/ddt.h>
51 #include "zfs_prop.h"
52 #include "zfeature_common.h"
53 
54 /*
55  * SPA locking
56  *
57  * There are four basic locks for managing spa_t structures:
58  *
59  * spa_namespace_lock (global mutex)
60  *
61  *	This lock must be acquired to do any of the following:
62  *
63  *		- Lookup a spa_t by name
64  *		- Add or remove a spa_t from the namespace
65  *		- Increase spa_refcount from non-zero
66  *		- Check if spa_refcount is zero
67  *		- Rename a spa_t
68  *		- add/remove/attach/detach devices
69  *		- Held for the duration of create/destroy/import/export
70  *
71  *	It does not need to handle recursion.  A create or destroy may
72  *	reference objects (files or zvols) in other pools, but by
73  *	definition they must have an existing reference, and will never need
74  *	to lookup a spa_t by name.
75  *
76  * spa_refcount (per-spa refcount_t protected by mutex)
77  *
78  *	This reference count keep track of any active users of the spa_t.  The
79  *	spa_t cannot be destroyed or freed while this is non-zero.  Internally,
80  *	the refcount is never really 'zero' - opening a pool implicitly keeps
81  *	some references in the DMU.  Internally we check against spa_minref, but
82  *	present the image of a zero/non-zero value to consumers.
83  *
84  * spa_config_lock[] (per-spa array of rwlocks)
85  *
86  *	This protects the spa_t from config changes, and must be held in
87  *	the following circumstances:
88  *
89  *		- RW_READER to perform I/O to the spa
90  *		- RW_WRITER to change the vdev config
91  *
92  * The locking order is fairly straightforward:
93  *
94  *		spa_namespace_lock	->	spa_refcount
95  *
96  *	The namespace lock must be acquired to increase the refcount from 0
97  *	or to check if it is zero.
98  *
99  *		spa_refcount		->	spa_config_lock[]
100  *
101  *	There must be at least one valid reference on the spa_t to acquire
102  *	the config lock.
103  *
104  *		spa_namespace_lock	->	spa_config_lock[]
105  *
106  *	The namespace lock must always be taken before the config lock.
107  *
108  *
109  * The spa_namespace_lock can be acquired directly and is globally visible.
110  *
111  * The namespace is manipulated using the following functions, all of which
112  * require the spa_namespace_lock to be held.
113  *
114  *	spa_lookup()		Lookup a spa_t by name.
115  *
116  *	spa_add()		Create a new spa_t in the namespace.
117  *
118  *	spa_remove()		Remove a spa_t from the namespace.  This also
119  *				frees up any memory associated with the spa_t.
120  *
121  *	spa_next()		Returns the next spa_t in the system, or the
122  *				first if NULL is passed.
123  *
124  *	spa_evict_all()		Shutdown and remove all spa_t structures in
125  *				the system.
126  *
127  *	spa_guid_exists()	Determine whether a pool/device guid exists.
128  *
129  * The spa_refcount is manipulated using the following functions:
130  *
131  *	spa_open_ref()		Adds a reference to the given spa_t.  Must be
132  *				called with spa_namespace_lock held if the
133  *				refcount is currently zero.
134  *
135  *	spa_close()		Remove a reference from the spa_t.  This will
136  *				not free the spa_t or remove it from the
137  *				namespace.  No locking is required.
138  *
139  *	spa_refcount_zero()	Returns true if the refcount is currently
140  *				zero.  Must be called with spa_namespace_lock
141  *				held.
142  *
143  * The spa_config_lock[] is an array of rwlocks, ordered as follows:
144  * SCL_CONFIG > SCL_STATE > SCL_ALLOC > SCL_ZIO > SCL_FREE > SCL_VDEV.
145  * spa_config_lock[] is manipulated with spa_config_{enter,exit,held}().
146  *
147  * To read the configuration, it suffices to hold one of these locks as reader.
148  * To modify the configuration, you must hold all locks as writer.  To modify
149  * vdev state without altering the vdev tree's topology (e.g. online/offline),
150  * you must hold SCL_STATE and SCL_ZIO as writer.
151  *
152  * We use these distinct config locks to avoid recursive lock entry.
153  * For example, spa_sync() (which holds SCL_CONFIG as reader) induces
154  * block allocations (SCL_ALLOC), which may require reading space maps
155  * from disk (dmu_read() -> zio_read() -> SCL_ZIO).
156  *
157  * The spa config locks cannot be normal rwlocks because we need the
158  * ability to hand off ownership.  For example, SCL_ZIO is acquired
159  * by the issuing thread and later released by an interrupt thread.
160  * They do, however, obey the usual write-wanted semantics to prevent
161  * writer (i.e. system administrator) starvation.
162  *
163  * The lock acquisition rules are as follows:
164  *
165  * SCL_CONFIG
166  *	Protects changes to the vdev tree topology, such as vdev
167  *	add/remove/attach/detach.  Protects the dirty config list
168  *	(spa_config_dirty_list) and the set of spares and l2arc devices.
169  *
170  * SCL_STATE
171  *	Protects changes to pool state and vdev state, such as vdev
172  *	online/offline/fault/degrade/clear.  Protects the dirty state list
173  *	(spa_state_dirty_list) and global pool state (spa_state).
174  *
175  * SCL_ALLOC
176  *	Protects changes to metaslab groups and classes.
177  *	Held as reader by metaslab_alloc() and metaslab_claim().
178  *
179  * SCL_ZIO
180  *	Held by bp-level zios (those which have no io_vd upon entry)
181  *	to prevent changes to the vdev tree.  The bp-level zio implicitly
182  *	protects all of its vdev child zios, which do not hold SCL_ZIO.
183  *
184  * SCL_FREE
185  *	Protects changes to metaslab groups and classes.
186  *	Held as reader by metaslab_free().  SCL_FREE is distinct from
187  *	SCL_ALLOC, and lower than SCL_ZIO, so that we can safely free
188  *	blocks in zio_done() while another i/o that holds either
189  *	SCL_ALLOC or SCL_ZIO is waiting for this i/o to complete.
190  *
191  * SCL_VDEV
192  *	Held as reader to prevent changes to the vdev tree during trivial
193  *	inquiries such as bp_get_dsize().  SCL_VDEV is distinct from the
194  *	other locks, and lower than all of them, to ensure that it's safe
195  *	to acquire regardless of caller context.
196  *
197  * In addition, the following rules apply:
198  *
199  * (a)	spa_props_lock protects pool properties, spa_config and spa_config_list.
200  *	The lock ordering is SCL_CONFIG > spa_props_lock.
201  *
202  * (b)	I/O operations on leaf vdevs.  For any zio operation that takes
203  *	an explicit vdev_t argument -- such as zio_ioctl(), zio_read_phys(),
204  *	or zio_write_phys() -- the caller must ensure that the config cannot
205  *	cannot change in the interim, and that the vdev cannot be reopened.
206  *	SCL_STATE as reader suffices for both.
207  *
208  * The vdev configuration is protected by spa_vdev_enter() / spa_vdev_exit().
209  *
210  *	spa_vdev_enter()	Acquire the namespace lock and the config lock
211  *				for writing.
212  *
213  *	spa_vdev_exit()		Release the config lock, wait for all I/O
214  *				to complete, sync the updated configs to the
215  *				cache, and release the namespace lock.
216  *
217  * vdev state is protected by spa_vdev_state_enter() / spa_vdev_state_exit().
218  * Like spa_vdev_enter/exit, these are convenience wrappers -- the actual
219  * locking is, always, based on spa_namespace_lock and spa_config_lock[].
220  *
221  * spa_rename() is also implemented within this file since it requires
222  * manipulation of the namespace.
223  */
224 
225 static avl_tree_t spa_namespace_avl;
226 kmutex_t spa_namespace_lock;
227 static kcondvar_t spa_namespace_cv;
228 static int spa_active_count;
229 int spa_max_replication_override = SPA_DVAS_PER_BP;
230 
231 static kmutex_t spa_spare_lock;
232 static avl_tree_t spa_spare_avl;
233 static kmutex_t spa_l2cache_lock;
234 static avl_tree_t spa_l2cache_avl;
235 
236 kmem_cache_t *spa_buffer_pool;
237 int spa_mode_global;
238 
239 #ifdef ZFS_DEBUG
240 /* Everything except dprintf and spa is on by default in debug builds */
241 int zfs_flags = ~(ZFS_DEBUG_DPRINTF | ZFS_DEBUG_SPA);
242 #else
243 int zfs_flags = 0;
244 #endif
245 
246 /*
247  * zfs_recover can be set to nonzero to attempt to recover from
248  * otherwise-fatal errors, typically caused by on-disk corruption.  When
249  * set, calls to zfs_panic_recover() will turn into warning messages.
250  * This should only be used as a last resort, as it typically results
251  * in leaked space, or worse.
252  */
253 boolean_t zfs_recover = B_FALSE;
254 
255 /*
256  * If destroy encounters an EIO while reading metadata (e.g. indirect
257  * blocks), space referenced by the missing metadata can not be freed.
258  * Normally this causes the background destroy to become "stalled", as
259  * it is unable to make forward progress.  While in this stalled state,
260  * all remaining space to free from the error-encountering filesystem is
261  * "temporarily leaked".  Set this flag to cause it to ignore the EIO,
262  * permanently leak the space from indirect blocks that can not be read,
263  * and continue to free everything else that it can.
264  *
265  * The default, "stalling" behavior is useful if the storage partially
266  * fails (i.e. some but not all i/os fail), and then later recovers.  In
267  * this case, we will be able to continue pool operations while it is
268  * partially failed, and when it recovers, we can continue to free the
269  * space, with no leaks.  However, note that this case is actually
270  * fairly rare.
271  *
272  * Typically pools either (a) fail completely (but perhaps temporarily,
273  * e.g. a top-level vdev going offline), or (b) have localized,
274  * permanent errors (e.g. disk returns the wrong data due to bit flip or
275  * firmware bug).  In case (a), this setting does not matter because the
276  * pool will be suspended and the sync thread will not be able to make
277  * forward progress regardless.  In case (b), because the error is
278  * permanent, the best we can do is leak the minimum amount of space,
279  * which is what setting this flag will do.  Therefore, it is reasonable
280  * for this flag to normally be set, but we chose the more conservative
281  * approach of not setting it, so that there is no possibility of
282  * leaking space in the "partial temporary" failure case.
283  */
284 boolean_t zfs_free_leak_on_eio = B_FALSE;
285 
286 /*
287  * Expiration time in milliseconds. This value has two meanings. First it is
288  * used to determine when the spa_deadman() logic should fire. By default the
289  * spa_deadman() will fire if spa_sync() has not completed in 1000 seconds.
290  * Secondly, the value determines if an I/O is considered "hung". Any I/O that
291  * has not completed in zfs_deadman_synctime_ms is considered "hung" resulting
292  * in a system panic.
293  */
294 uint64_t zfs_deadman_synctime_ms = 1000000ULL;
295 
296 /*
297  * Check time in milliseconds. This defines the frequency at which we check
298  * for hung I/O.
299  */
300 uint64_t zfs_deadman_checktime_ms = 5000ULL;
301 
302 /*
303  * Override the zfs deadman behavior via /etc/system. By default the
304  * deadman is enabled except on VMware and sparc deployments.
305  */
306 int zfs_deadman_enabled = -1;
307 
308 /*
309  * The worst case is single-sector max-parity RAID-Z blocks, in which
310  * case the space requirement is exactly (VDEV_RAIDZ_MAXPARITY + 1)
311  * times the size; so just assume that.  Add to this the fact that
312  * we can have up to 3 DVAs per bp, and one more factor of 2 because
313  * the block may be dittoed with up to 3 DVAs by ddt_sync().  All together,
314  * the worst case is:
315  *     (VDEV_RAIDZ_MAXPARITY + 1) * SPA_DVAS_PER_BP * 2 == 24
316  */
317 int spa_asize_inflation = 24;
318 
319 /*
320  * Normally, we don't allow the last 3.2% (1/(2^spa_slop_shift)) of space in
321  * the pool to be consumed.  This ensures that we don't run the pool
322  * completely out of space, due to unaccounted changes (e.g. to the MOS).
323  * It also limits the worst-case time to allocate space.  If we have
324  * less than this amount of free space, most ZPL operations (e.g. write,
325  * create) will return ENOSPC.
326  *
327  * Certain operations (e.g. file removal, most administrative actions) can
328  * use half the slop space.  They will only return ENOSPC if less than half
329  * the slop space is free.  Typically, once the pool has less than the slop
330  * space free, the user will use these operations to free up space in the pool.
331  * These are the operations that call dsl_pool_adjustedsize() with the netfree
332  * argument set to TRUE.
333  *
334  * A very restricted set of operations are always permitted, regardless of
335  * the amount of free space.  These are the operations that call
336  * dsl_sync_task(ZFS_SPACE_CHECK_NONE), e.g. "zfs destroy".  If these
337  * operations result in a net increase in the amount of space used,
338  * it is possible to run the pool completely out of space, causing it to
339  * be permanently read-only.
340  *
341  * See also the comments in zfs_space_check_t.
342  */
343 int spa_slop_shift = 5;
344 
345 /*
346  * ==========================================================================
347  * SPA config locking
348  * ==========================================================================
349  */
350 static void
351 spa_config_lock_init(spa_t *spa)
352 {
353 	for (int i = 0; i < SCL_LOCKS; i++) {
354 		spa_config_lock_t *scl = &spa->spa_config_lock[i];
355 		mutex_init(&scl->scl_lock, NULL, MUTEX_DEFAULT, NULL);
356 		cv_init(&scl->scl_cv, NULL, CV_DEFAULT, NULL);
357 		refcount_create_untracked(&scl->scl_count);
358 		scl->scl_writer = NULL;
359 		scl->scl_write_wanted = 0;
360 	}
361 }
362 
363 static void
364 spa_config_lock_destroy(spa_t *spa)
365 {
366 	for (int i = 0; i < SCL_LOCKS; i++) {
367 		spa_config_lock_t *scl = &spa->spa_config_lock[i];
368 		mutex_destroy(&scl->scl_lock);
369 		cv_destroy(&scl->scl_cv);
370 		refcount_destroy(&scl->scl_count);
371 		ASSERT(scl->scl_writer == NULL);
372 		ASSERT(scl->scl_write_wanted == 0);
373 	}
374 }
375 
376 int
377 spa_config_tryenter(spa_t *spa, int locks, void *tag, krw_t rw)
378 {
379 	for (int i = 0; i < SCL_LOCKS; i++) {
380 		spa_config_lock_t *scl = &spa->spa_config_lock[i];
381 		if (!(locks & (1 << i)))
382 			continue;
383 		mutex_enter(&scl->scl_lock);
384 		if (rw == RW_READER) {
385 			if (scl->scl_writer || scl->scl_write_wanted) {
386 				mutex_exit(&scl->scl_lock);
387 				spa_config_exit(spa, locks ^ (1 << i), tag);
388 				return (0);
389 			}
390 		} else {
391 			ASSERT(scl->scl_writer != curthread);
392 			if (!refcount_is_zero(&scl->scl_count)) {
393 				mutex_exit(&scl->scl_lock);
394 				spa_config_exit(spa, locks ^ (1 << i), tag);
395 				return (0);
396 			}
397 			scl->scl_writer = curthread;
398 		}
399 		(void) refcount_add(&scl->scl_count, tag);
400 		mutex_exit(&scl->scl_lock);
401 	}
402 	return (1);
403 }
404 
405 void
406 spa_config_enter(spa_t *spa, int locks, void *tag, krw_t rw)
407 {
408 	int wlocks_held = 0;
409 
410 	ASSERT3U(SCL_LOCKS, <, sizeof (wlocks_held) * NBBY);
411 
412 	for (int i = 0; i < SCL_LOCKS; i++) {
413 		spa_config_lock_t *scl = &spa->spa_config_lock[i];
414 		if (scl->scl_writer == curthread)
415 			wlocks_held |= (1 << i);
416 		if (!(locks & (1 << i)))
417 			continue;
418 		mutex_enter(&scl->scl_lock);
419 		if (rw == RW_READER) {
420 			while (scl->scl_writer || scl->scl_write_wanted) {
421 				cv_wait(&scl->scl_cv, &scl->scl_lock);
422 			}
423 		} else {
424 			ASSERT(scl->scl_writer != curthread);
425 			while (!refcount_is_zero(&scl->scl_count)) {
426 				scl->scl_write_wanted++;
427 				cv_wait(&scl->scl_cv, &scl->scl_lock);
428 				scl->scl_write_wanted--;
429 			}
430 			scl->scl_writer = curthread;
431 		}
432 		(void) refcount_add(&scl->scl_count, tag);
433 		mutex_exit(&scl->scl_lock);
434 	}
435 	ASSERT(wlocks_held <= locks);
436 }
437 
438 void
439 spa_config_exit(spa_t *spa, int locks, void *tag)
440 {
441 	for (int i = SCL_LOCKS - 1; i >= 0; i--) {
442 		spa_config_lock_t *scl = &spa->spa_config_lock[i];
443 		if (!(locks & (1 << i)))
444 			continue;
445 		mutex_enter(&scl->scl_lock);
446 		ASSERT(!refcount_is_zero(&scl->scl_count));
447 		if (refcount_remove(&scl->scl_count, tag) == 0) {
448 			ASSERT(scl->scl_writer == NULL ||
449 			    scl->scl_writer == curthread);
450 			scl->scl_writer = NULL;	/* OK in either case */
451 			cv_broadcast(&scl->scl_cv);
452 		}
453 		mutex_exit(&scl->scl_lock);
454 	}
455 }
456 
457 int
458 spa_config_held(spa_t *spa, int locks, krw_t rw)
459 {
460 	int locks_held = 0;
461 
462 	for (int i = 0; i < SCL_LOCKS; i++) {
463 		spa_config_lock_t *scl = &spa->spa_config_lock[i];
464 		if (!(locks & (1 << i)))
465 			continue;
466 		if ((rw == RW_READER && !refcount_is_zero(&scl->scl_count)) ||
467 		    (rw == RW_WRITER && scl->scl_writer == curthread))
468 			locks_held |= 1 << i;
469 	}
470 
471 	return (locks_held);
472 }
473 
474 /*
475  * ==========================================================================
476  * SPA namespace functions
477  * ==========================================================================
478  */
479 
480 /*
481  * Lookup the named spa_t in the AVL tree.  The spa_namespace_lock must be held.
482  * Returns NULL if no matching spa_t is found.
483  */
484 spa_t *
485 spa_lookup(const char *name)
486 {
487 	static spa_t search;	/* spa_t is large; don't allocate on stack */
488 	spa_t *spa;
489 	avl_index_t where;
490 	char *cp;
491 
492 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
493 
494 	(void) strlcpy(search.spa_name, name, sizeof (search.spa_name));
495 
496 	/*
497 	 * If it's a full dataset name, figure out the pool name and
498 	 * just use that.
499 	 */
500 	cp = strpbrk(search.spa_name, "/@#");
501 	if (cp != NULL)
502 		*cp = '\0';
503 
504 	spa = avl_find(&spa_namespace_avl, &search, &where);
505 
506 	return (spa);
507 }
508 
509 /*
510  * Fires when spa_sync has not completed within zfs_deadman_synctime_ms.
511  * If the zfs_deadman_enabled flag is set then it inspects all vdev queues
512  * looking for potentially hung I/Os.
513  */
514 void
515 spa_deadman(void *arg)
516 {
517 	spa_t *spa = arg;
518 
519 	/*
520 	 * Disable the deadman timer if the pool is suspended.
521 	 */
522 	if (spa_suspended(spa)) {
523 		VERIFY(cyclic_reprogram(spa->spa_deadman_cycid, CY_INFINITY));
524 		return;
525 	}
526 
527 	zfs_dbgmsg("slow spa_sync: started %llu seconds ago, calls %llu",
528 	    (gethrtime() - spa->spa_sync_starttime) / NANOSEC,
529 	    ++spa->spa_deadman_calls);
530 	if (zfs_deadman_enabled)
531 		vdev_deadman(spa->spa_root_vdev);
532 }
533 
534 /*
535  * Create an uninitialized spa_t with the given name.  Requires
536  * spa_namespace_lock.  The caller must ensure that the spa_t doesn't already
537  * exist by calling spa_lookup() first.
538  */
539 spa_t *
540 spa_add(const char *name, nvlist_t *config, const char *altroot)
541 {
542 	spa_t *spa;
543 	spa_config_dirent_t *dp;
544 	cyc_handler_t hdlr;
545 	cyc_time_t when;
546 
547 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
548 
549 	spa = kmem_zalloc(sizeof (spa_t), KM_SLEEP);
550 
551 	mutex_init(&spa->spa_async_lock, NULL, MUTEX_DEFAULT, NULL);
552 	mutex_init(&spa->spa_errlist_lock, NULL, MUTEX_DEFAULT, NULL);
553 	mutex_init(&spa->spa_errlog_lock, NULL, MUTEX_DEFAULT, NULL);
554 	mutex_init(&spa->spa_history_lock, NULL, MUTEX_DEFAULT, NULL);
555 	mutex_init(&spa->spa_proc_lock, NULL, MUTEX_DEFAULT, NULL);
556 	mutex_init(&spa->spa_props_lock, NULL, MUTEX_DEFAULT, NULL);
557 	mutex_init(&spa->spa_scrub_lock, NULL, MUTEX_DEFAULT, NULL);
558 	mutex_init(&spa->spa_suspend_lock, NULL, MUTEX_DEFAULT, NULL);
559 	mutex_init(&spa->spa_vdev_top_lock, NULL, MUTEX_DEFAULT, NULL);
560 	mutex_init(&spa->spa_iokstat_lock, NULL, MUTEX_DEFAULT, NULL);
561 
562 	cv_init(&spa->spa_async_cv, NULL, CV_DEFAULT, NULL);
563 	cv_init(&spa->spa_proc_cv, NULL, CV_DEFAULT, NULL);
564 	cv_init(&spa->spa_scrub_io_cv, NULL, CV_DEFAULT, NULL);
565 	cv_init(&spa->spa_suspend_cv, NULL, CV_DEFAULT, NULL);
566 
567 	for (int t = 0; t < TXG_SIZE; t++)
568 		bplist_create(&spa->spa_free_bplist[t]);
569 
570 	(void) strlcpy(spa->spa_name, name, sizeof (spa->spa_name));
571 	spa->spa_state = POOL_STATE_UNINITIALIZED;
572 	spa->spa_freeze_txg = UINT64_MAX;
573 	spa->spa_final_txg = UINT64_MAX;
574 	spa->spa_load_max_txg = UINT64_MAX;
575 	spa->spa_proc = &p0;
576 	spa->spa_proc_state = SPA_PROC_NONE;
577 
578 	hdlr.cyh_func = spa_deadman;
579 	hdlr.cyh_arg = spa;
580 	hdlr.cyh_level = CY_LOW_LEVEL;
581 
582 	spa->spa_deadman_synctime = MSEC2NSEC(zfs_deadman_synctime_ms);
583 
584 	/*
585 	 * This determines how often we need to check for hung I/Os after
586 	 * the cyclic has already fired. Since checking for hung I/Os is
587 	 * an expensive operation we don't want to check too frequently.
588 	 * Instead wait for 5 seconds before checking again.
589 	 */
590 	when.cyt_interval = MSEC2NSEC(zfs_deadman_checktime_ms);
591 	when.cyt_when = CY_INFINITY;
592 	mutex_enter(&cpu_lock);
593 	spa->spa_deadman_cycid = cyclic_add(&hdlr, &when);
594 	mutex_exit(&cpu_lock);
595 
596 	refcount_create(&spa->spa_refcount);
597 	spa_config_lock_init(spa);
598 
599 	avl_add(&spa_namespace_avl, spa);
600 
601 	/*
602 	 * Set the alternate root, if there is one.
603 	 */
604 	if (altroot) {
605 		spa->spa_root = spa_strdup(altroot);
606 		spa_active_count++;
607 	}
608 
609 	/*
610 	 * Every pool starts with the default cachefile
611 	 */
612 	list_create(&spa->spa_config_list, sizeof (spa_config_dirent_t),
613 	    offsetof(spa_config_dirent_t, scd_link));
614 
615 	dp = kmem_zalloc(sizeof (spa_config_dirent_t), KM_SLEEP);
616 	dp->scd_path = altroot ? NULL : spa_strdup(spa_config_path);
617 	list_insert_head(&spa->spa_config_list, dp);
618 
619 	VERIFY(nvlist_alloc(&spa->spa_load_info, NV_UNIQUE_NAME,
620 	    KM_SLEEP) == 0);
621 
622 	if (config != NULL) {
623 		nvlist_t *features;
624 
625 		if (nvlist_lookup_nvlist(config, ZPOOL_CONFIG_FEATURES_FOR_READ,
626 		    &features) == 0) {
627 			VERIFY(nvlist_dup(features, &spa->spa_label_features,
628 			    0) == 0);
629 		}
630 
631 		VERIFY(nvlist_dup(config, &spa->spa_config, 0) == 0);
632 	}
633 
634 	if (spa->spa_label_features == NULL) {
635 		VERIFY(nvlist_alloc(&spa->spa_label_features, NV_UNIQUE_NAME,
636 		    KM_SLEEP) == 0);
637 	}
638 
639 	spa->spa_iokstat = kstat_create("zfs", 0, name,
640 	    "disk", KSTAT_TYPE_IO, 1, 0);
641 	if (spa->spa_iokstat) {
642 		spa->spa_iokstat->ks_lock = &spa->spa_iokstat_lock;
643 		kstat_install(spa->spa_iokstat);
644 	}
645 
646 	spa->spa_debug = ((zfs_flags & ZFS_DEBUG_SPA) != 0);
647 
648 	/*
649 	 * As a pool is being created, treat all features as disabled by
650 	 * setting SPA_FEATURE_DISABLED for all entries in the feature
651 	 * refcount cache.
652 	 */
653 	for (int i = 0; i < SPA_FEATURES; i++) {
654 		spa->spa_feat_refcount_cache[i] = SPA_FEATURE_DISABLED;
655 	}
656 
657 	return (spa);
658 }
659 
660 /*
661  * Removes a spa_t from the namespace, freeing up any memory used.  Requires
662  * spa_namespace_lock.  This is called only after the spa_t has been closed and
663  * deactivated.
664  */
665 void
666 spa_remove(spa_t *spa)
667 {
668 	spa_config_dirent_t *dp;
669 
670 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
671 	ASSERT(spa->spa_state == POOL_STATE_UNINITIALIZED);
672 
673 	nvlist_free(spa->spa_config_splitting);
674 
675 	avl_remove(&spa_namespace_avl, spa);
676 	cv_broadcast(&spa_namespace_cv);
677 
678 	if (spa->spa_root) {
679 		spa_strfree(spa->spa_root);
680 		spa_active_count--;
681 	}
682 
683 	while ((dp = list_head(&spa->spa_config_list)) != NULL) {
684 		list_remove(&spa->spa_config_list, dp);
685 		if (dp->scd_path != NULL)
686 			spa_strfree(dp->scd_path);
687 		kmem_free(dp, sizeof (spa_config_dirent_t));
688 	}
689 
690 	list_destroy(&spa->spa_config_list);
691 
692 	nvlist_free(spa->spa_label_features);
693 	nvlist_free(spa->spa_load_info);
694 	spa_config_set(spa, NULL);
695 
696 	mutex_enter(&cpu_lock);
697 	if (spa->spa_deadman_cycid != CYCLIC_NONE)
698 		cyclic_remove(spa->spa_deadman_cycid);
699 	mutex_exit(&cpu_lock);
700 	spa->spa_deadman_cycid = CYCLIC_NONE;
701 
702 	refcount_destroy(&spa->spa_refcount);
703 
704 	spa_config_lock_destroy(spa);
705 
706 	kstat_delete(spa->spa_iokstat);
707 	spa->spa_iokstat = NULL;
708 
709 	for (int t = 0; t < TXG_SIZE; t++)
710 		bplist_destroy(&spa->spa_free_bplist[t]);
711 
712 	cv_destroy(&spa->spa_async_cv);
713 	cv_destroy(&spa->spa_proc_cv);
714 	cv_destroy(&spa->spa_scrub_io_cv);
715 	cv_destroy(&spa->spa_suspend_cv);
716 
717 	mutex_destroy(&spa->spa_async_lock);
718 	mutex_destroy(&spa->spa_errlist_lock);
719 	mutex_destroy(&spa->spa_errlog_lock);
720 	mutex_destroy(&spa->spa_history_lock);
721 	mutex_destroy(&spa->spa_proc_lock);
722 	mutex_destroy(&spa->spa_props_lock);
723 	mutex_destroy(&spa->spa_scrub_lock);
724 	mutex_destroy(&spa->spa_suspend_lock);
725 	mutex_destroy(&spa->spa_vdev_top_lock);
726 	mutex_destroy(&spa->spa_iokstat_lock);
727 
728 	kmem_free(spa, sizeof (spa_t));
729 }
730 
731 /*
732  * Given a pool, return the next pool in the namespace, or NULL if there is
733  * none.  If 'prev' is NULL, return the first pool.
734  */
735 spa_t *
736 spa_next(spa_t *prev)
737 {
738 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
739 
740 	if (prev)
741 		return (AVL_NEXT(&spa_namespace_avl, prev));
742 	else
743 		return (avl_first(&spa_namespace_avl));
744 }
745 
746 /*
747  * ==========================================================================
748  * SPA refcount functions
749  * ==========================================================================
750  */
751 
752 /*
753  * Add a reference to the given spa_t.  Must have at least one reference, or
754  * have the namespace lock held.
755  */
756 void
757 spa_open_ref(spa_t *spa, void *tag)
758 {
759 	ASSERT(refcount_count(&spa->spa_refcount) >= spa->spa_minref ||
760 	    MUTEX_HELD(&spa_namespace_lock));
761 	(void) refcount_add(&spa->spa_refcount, tag);
762 }
763 
764 /*
765  * Remove a reference to the given spa_t.  Must have at least one reference, or
766  * have the namespace lock held.
767  */
768 void
769 spa_close(spa_t *spa, void *tag)
770 {
771 	ASSERT(refcount_count(&spa->spa_refcount) > spa->spa_minref ||
772 	    MUTEX_HELD(&spa_namespace_lock));
773 	(void) refcount_remove(&spa->spa_refcount, tag);
774 }
775 
776 /*
777  * Check to see if the spa refcount is zero.  Must be called with
778  * spa_namespace_lock held.  We really compare against spa_minref, which is the
779  * number of references acquired when opening a pool
780  */
781 boolean_t
782 spa_refcount_zero(spa_t *spa)
783 {
784 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
785 
786 	return (refcount_count(&spa->spa_refcount) == spa->spa_minref);
787 }
788 
789 /*
790  * ==========================================================================
791  * SPA spare and l2cache tracking
792  * ==========================================================================
793  */
794 
795 /*
796  * Hot spares and cache devices are tracked using the same code below,
797  * for 'auxiliary' devices.
798  */
799 
800 typedef struct spa_aux {
801 	uint64_t	aux_guid;
802 	uint64_t	aux_pool;
803 	avl_node_t	aux_avl;
804 	int		aux_count;
805 } spa_aux_t;
806 
807 static int
808 spa_aux_compare(const void *a, const void *b)
809 {
810 	const spa_aux_t *sa = a;
811 	const spa_aux_t *sb = b;
812 
813 	if (sa->aux_guid < sb->aux_guid)
814 		return (-1);
815 	else if (sa->aux_guid > sb->aux_guid)
816 		return (1);
817 	else
818 		return (0);
819 }
820 
821 void
822 spa_aux_add(vdev_t *vd, avl_tree_t *avl)
823 {
824 	avl_index_t where;
825 	spa_aux_t search;
826 	spa_aux_t *aux;
827 
828 	search.aux_guid = vd->vdev_guid;
829 	if ((aux = avl_find(avl, &search, &where)) != NULL) {
830 		aux->aux_count++;
831 	} else {
832 		aux = kmem_zalloc(sizeof (spa_aux_t), KM_SLEEP);
833 		aux->aux_guid = vd->vdev_guid;
834 		aux->aux_count = 1;
835 		avl_insert(avl, aux, where);
836 	}
837 }
838 
839 void
840 spa_aux_remove(vdev_t *vd, avl_tree_t *avl)
841 {
842 	spa_aux_t search;
843 	spa_aux_t *aux;
844 	avl_index_t where;
845 
846 	search.aux_guid = vd->vdev_guid;
847 	aux = avl_find(avl, &search, &where);
848 
849 	ASSERT(aux != NULL);
850 
851 	if (--aux->aux_count == 0) {
852 		avl_remove(avl, aux);
853 		kmem_free(aux, sizeof (spa_aux_t));
854 	} else if (aux->aux_pool == spa_guid(vd->vdev_spa)) {
855 		aux->aux_pool = 0ULL;
856 	}
857 }
858 
859 boolean_t
860 spa_aux_exists(uint64_t guid, uint64_t *pool, int *refcnt, avl_tree_t *avl)
861 {
862 	spa_aux_t search, *found;
863 
864 	search.aux_guid = guid;
865 	found = avl_find(avl, &search, NULL);
866 
867 	if (pool) {
868 		if (found)
869 			*pool = found->aux_pool;
870 		else
871 			*pool = 0ULL;
872 	}
873 
874 	if (refcnt) {
875 		if (found)
876 			*refcnt = found->aux_count;
877 		else
878 			*refcnt = 0;
879 	}
880 
881 	return (found != NULL);
882 }
883 
884 void
885 spa_aux_activate(vdev_t *vd, avl_tree_t *avl)
886 {
887 	spa_aux_t search, *found;
888 	avl_index_t where;
889 
890 	search.aux_guid = vd->vdev_guid;
891 	found = avl_find(avl, &search, &where);
892 	ASSERT(found != NULL);
893 	ASSERT(found->aux_pool == 0ULL);
894 
895 	found->aux_pool = spa_guid(vd->vdev_spa);
896 }
897 
898 /*
899  * Spares are tracked globally due to the following constraints:
900  *
901  * 	- A spare may be part of multiple pools.
902  * 	- A spare may be added to a pool even if it's actively in use within
903  *	  another pool.
904  * 	- A spare in use in any pool can only be the source of a replacement if
905  *	  the target is a spare in the same pool.
906  *
907  * We keep track of all spares on the system through the use of a reference
908  * counted AVL tree.  When a vdev is added as a spare, or used as a replacement
909  * spare, then we bump the reference count in the AVL tree.  In addition, we set
910  * the 'vdev_isspare' member to indicate that the device is a spare (active or
911  * inactive).  When a spare is made active (used to replace a device in the
912  * pool), we also keep track of which pool its been made a part of.
913  *
914  * The 'spa_spare_lock' protects the AVL tree.  These functions are normally
915  * called under the spa_namespace lock as part of vdev reconfiguration.  The
916  * separate spare lock exists for the status query path, which does not need to
917  * be completely consistent with respect to other vdev configuration changes.
918  */
919 
920 static int
921 spa_spare_compare(const void *a, const void *b)
922 {
923 	return (spa_aux_compare(a, b));
924 }
925 
926 void
927 spa_spare_add(vdev_t *vd)
928 {
929 	mutex_enter(&spa_spare_lock);
930 	ASSERT(!vd->vdev_isspare);
931 	spa_aux_add(vd, &spa_spare_avl);
932 	vd->vdev_isspare = B_TRUE;
933 	mutex_exit(&spa_spare_lock);
934 }
935 
936 void
937 spa_spare_remove(vdev_t *vd)
938 {
939 	mutex_enter(&spa_spare_lock);
940 	ASSERT(vd->vdev_isspare);
941 	spa_aux_remove(vd, &spa_spare_avl);
942 	vd->vdev_isspare = B_FALSE;
943 	mutex_exit(&spa_spare_lock);
944 }
945 
946 boolean_t
947 spa_spare_exists(uint64_t guid, uint64_t *pool, int *refcnt)
948 {
949 	boolean_t found;
950 
951 	mutex_enter(&spa_spare_lock);
952 	found = spa_aux_exists(guid, pool, refcnt, &spa_spare_avl);
953 	mutex_exit(&spa_spare_lock);
954 
955 	return (found);
956 }
957 
958 void
959 spa_spare_activate(vdev_t *vd)
960 {
961 	mutex_enter(&spa_spare_lock);
962 	ASSERT(vd->vdev_isspare);
963 	spa_aux_activate(vd, &spa_spare_avl);
964 	mutex_exit(&spa_spare_lock);
965 }
966 
967 /*
968  * Level 2 ARC devices are tracked globally for the same reasons as spares.
969  * Cache devices currently only support one pool per cache device, and so
970  * for these devices the aux reference count is currently unused beyond 1.
971  */
972 
973 static int
974 spa_l2cache_compare(const void *a, const void *b)
975 {
976 	return (spa_aux_compare(a, b));
977 }
978 
979 void
980 spa_l2cache_add(vdev_t *vd)
981 {
982 	mutex_enter(&spa_l2cache_lock);
983 	ASSERT(!vd->vdev_isl2cache);
984 	spa_aux_add(vd, &spa_l2cache_avl);
985 	vd->vdev_isl2cache = B_TRUE;
986 	mutex_exit(&spa_l2cache_lock);
987 }
988 
989 void
990 spa_l2cache_remove(vdev_t *vd)
991 {
992 	mutex_enter(&spa_l2cache_lock);
993 	ASSERT(vd->vdev_isl2cache);
994 	spa_aux_remove(vd, &spa_l2cache_avl);
995 	vd->vdev_isl2cache = B_FALSE;
996 	mutex_exit(&spa_l2cache_lock);
997 }
998 
999 boolean_t
1000 spa_l2cache_exists(uint64_t guid, uint64_t *pool)
1001 {
1002 	boolean_t found;
1003 
1004 	mutex_enter(&spa_l2cache_lock);
1005 	found = spa_aux_exists(guid, pool, NULL, &spa_l2cache_avl);
1006 	mutex_exit(&spa_l2cache_lock);
1007 
1008 	return (found);
1009 }
1010 
1011 void
1012 spa_l2cache_activate(vdev_t *vd)
1013 {
1014 	mutex_enter(&spa_l2cache_lock);
1015 	ASSERT(vd->vdev_isl2cache);
1016 	spa_aux_activate(vd, &spa_l2cache_avl);
1017 	mutex_exit(&spa_l2cache_lock);
1018 }
1019 
1020 /*
1021  * ==========================================================================
1022  * SPA vdev locking
1023  * ==========================================================================
1024  */
1025 
1026 /*
1027  * Lock the given spa_t for the purpose of adding or removing a vdev.
1028  * Grabs the global spa_namespace_lock plus the spa config lock for writing.
1029  * It returns the next transaction group for the spa_t.
1030  */
1031 uint64_t
1032 spa_vdev_enter(spa_t *spa)
1033 {
1034 	mutex_enter(&spa->spa_vdev_top_lock);
1035 	mutex_enter(&spa_namespace_lock);
1036 	return (spa_vdev_config_enter(spa));
1037 }
1038 
1039 /*
1040  * Internal implementation for spa_vdev_enter().  Used when a vdev
1041  * operation requires multiple syncs (i.e. removing a device) while
1042  * keeping the spa_namespace_lock held.
1043  */
1044 uint64_t
1045 spa_vdev_config_enter(spa_t *spa)
1046 {
1047 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
1048 
1049 	spa_config_enter(spa, SCL_ALL, spa, RW_WRITER);
1050 
1051 	return (spa_last_synced_txg(spa) + 1);
1052 }
1053 
1054 /*
1055  * Used in combination with spa_vdev_config_enter() to allow the syncing
1056  * of multiple transactions without releasing the spa_namespace_lock.
1057  */
1058 void
1059 spa_vdev_config_exit(spa_t *spa, vdev_t *vd, uint64_t txg, int error, char *tag)
1060 {
1061 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
1062 
1063 	int config_changed = B_FALSE;
1064 
1065 	ASSERT(txg > spa_last_synced_txg(spa));
1066 
1067 	spa->spa_pending_vdev = NULL;
1068 
1069 	/*
1070 	 * Reassess the DTLs.
1071 	 */
1072 	vdev_dtl_reassess(spa->spa_root_vdev, 0, 0, B_FALSE);
1073 
1074 	if (error == 0 && !list_is_empty(&spa->spa_config_dirty_list)) {
1075 		config_changed = B_TRUE;
1076 		spa->spa_config_generation++;
1077 	}
1078 
1079 	/*
1080 	 * Verify the metaslab classes.
1081 	 */
1082 	ASSERT(metaslab_class_validate(spa_normal_class(spa)) == 0);
1083 	ASSERT(metaslab_class_validate(spa_log_class(spa)) == 0);
1084 
1085 	spa_config_exit(spa, SCL_ALL, spa);
1086 
1087 	/*
1088 	 * Panic the system if the specified tag requires it.  This
1089 	 * is useful for ensuring that configurations are updated
1090 	 * transactionally.
1091 	 */
1092 	if (zio_injection_enabled)
1093 		zio_handle_panic_injection(spa, tag, 0);
1094 
1095 	/*
1096 	 * Note: this txg_wait_synced() is important because it ensures
1097 	 * that there won't be more than one config change per txg.
1098 	 * This allows us to use the txg as the generation number.
1099 	 */
1100 	if (error == 0)
1101 		txg_wait_synced(spa->spa_dsl_pool, txg);
1102 
1103 	if (vd != NULL) {
1104 		ASSERT(!vd->vdev_detached || vd->vdev_dtl_sm == NULL);
1105 		spa_config_enter(spa, SCL_ALL, spa, RW_WRITER);
1106 		vdev_free(vd);
1107 		spa_config_exit(spa, SCL_ALL, spa);
1108 	}
1109 
1110 	/*
1111 	 * If the config changed, update the config cache.
1112 	 */
1113 	if (config_changed)
1114 		spa_config_sync(spa, B_FALSE, B_TRUE);
1115 }
1116 
1117 /*
1118  * Unlock the spa_t after adding or removing a vdev.  Besides undoing the
1119  * locking of spa_vdev_enter(), we also want make sure the transactions have
1120  * synced to disk, and then update the global configuration cache with the new
1121  * information.
1122  */
1123 int
1124 spa_vdev_exit(spa_t *spa, vdev_t *vd, uint64_t txg, int error)
1125 {
1126 	spa_vdev_config_exit(spa, vd, txg, error, FTAG);
1127 	mutex_exit(&spa_namespace_lock);
1128 	mutex_exit(&spa->spa_vdev_top_lock);
1129 
1130 	return (error);
1131 }
1132 
1133 /*
1134  * Lock the given spa_t for the purpose of changing vdev state.
1135  */
1136 void
1137 spa_vdev_state_enter(spa_t *spa, int oplocks)
1138 {
1139 	int locks = SCL_STATE_ALL | oplocks;
1140 
1141 	/*
1142 	 * Root pools may need to read of the underlying devfs filesystem
1143 	 * when opening up a vdev.  Unfortunately if we're holding the
1144 	 * SCL_ZIO lock it will result in a deadlock when we try to issue
1145 	 * the read from the root filesystem.  Instead we "prefetch"
1146 	 * the associated vnodes that we need prior to opening the
1147 	 * underlying devices and cache them so that we can prevent
1148 	 * any I/O when we are doing the actual open.
1149 	 */
1150 	if (spa_is_root(spa)) {
1151 		int low = locks & ~(SCL_ZIO - 1);
1152 		int high = locks & ~low;
1153 
1154 		spa_config_enter(spa, high, spa, RW_WRITER);
1155 		vdev_hold(spa->spa_root_vdev);
1156 		spa_config_enter(spa, low, spa, RW_WRITER);
1157 	} else {
1158 		spa_config_enter(spa, locks, spa, RW_WRITER);
1159 	}
1160 	spa->spa_vdev_locks = locks;
1161 }
1162 
1163 int
1164 spa_vdev_state_exit(spa_t *spa, vdev_t *vd, int error)
1165 {
1166 	boolean_t config_changed = B_FALSE;
1167 
1168 	if (vd != NULL || error == 0)
1169 		vdev_dtl_reassess(vd ? vd->vdev_top : spa->spa_root_vdev,
1170 		    0, 0, B_FALSE);
1171 
1172 	if (vd != NULL) {
1173 		vdev_state_dirty(vd->vdev_top);
1174 		config_changed = B_TRUE;
1175 		spa->spa_config_generation++;
1176 	}
1177 
1178 	if (spa_is_root(spa))
1179 		vdev_rele(spa->spa_root_vdev);
1180 
1181 	ASSERT3U(spa->spa_vdev_locks, >=, SCL_STATE_ALL);
1182 	spa_config_exit(spa, spa->spa_vdev_locks, spa);
1183 
1184 	/*
1185 	 * If anything changed, wait for it to sync.  This ensures that,
1186 	 * from the system administrator's perspective, zpool(1M) commands
1187 	 * are synchronous.  This is important for things like zpool offline:
1188 	 * when the command completes, you expect no further I/O from ZFS.
1189 	 */
1190 	if (vd != NULL)
1191 		txg_wait_synced(spa->spa_dsl_pool, 0);
1192 
1193 	/*
1194 	 * If the config changed, update the config cache.
1195 	 */
1196 	if (config_changed) {
1197 		mutex_enter(&spa_namespace_lock);
1198 		spa_config_sync(spa, B_FALSE, B_TRUE);
1199 		mutex_exit(&spa_namespace_lock);
1200 	}
1201 
1202 	return (error);
1203 }
1204 
1205 /*
1206  * ==========================================================================
1207  * Miscellaneous functions
1208  * ==========================================================================
1209  */
1210 
1211 void
1212 spa_activate_mos_feature(spa_t *spa, const char *feature, dmu_tx_t *tx)
1213 {
1214 	if (!nvlist_exists(spa->spa_label_features, feature)) {
1215 		fnvlist_add_boolean(spa->spa_label_features, feature);
1216 		/*
1217 		 * When we are creating the pool (tx_txg==TXG_INITIAL), we can't
1218 		 * dirty the vdev config because lock SCL_CONFIG is not held.
1219 		 * Thankfully, in this case we don't need to dirty the config
1220 		 * because it will be written out anyway when we finish
1221 		 * creating the pool.
1222 		 */
1223 		if (tx->tx_txg != TXG_INITIAL)
1224 			vdev_config_dirty(spa->spa_root_vdev);
1225 	}
1226 }
1227 
1228 void
1229 spa_deactivate_mos_feature(spa_t *spa, const char *feature)
1230 {
1231 	if (nvlist_remove_all(spa->spa_label_features, feature) == 0)
1232 		vdev_config_dirty(spa->spa_root_vdev);
1233 }
1234 
1235 /*
1236  * Rename a spa_t.
1237  */
1238 int
1239 spa_rename(const char *name, const char *newname)
1240 {
1241 	spa_t *spa;
1242 	int err;
1243 
1244 	/*
1245 	 * Lookup the spa_t and grab the config lock for writing.  We need to
1246 	 * actually open the pool so that we can sync out the necessary labels.
1247 	 * It's OK to call spa_open() with the namespace lock held because we
1248 	 * allow recursive calls for other reasons.
1249 	 */
1250 	mutex_enter(&spa_namespace_lock);
1251 	if ((err = spa_open(name, &spa, FTAG)) != 0) {
1252 		mutex_exit(&spa_namespace_lock);
1253 		return (err);
1254 	}
1255 
1256 	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
1257 
1258 	avl_remove(&spa_namespace_avl, spa);
1259 	(void) strlcpy(spa->spa_name, newname, sizeof (spa->spa_name));
1260 	avl_add(&spa_namespace_avl, spa);
1261 
1262 	/*
1263 	 * Sync all labels to disk with the new names by marking the root vdev
1264 	 * dirty and waiting for it to sync.  It will pick up the new pool name
1265 	 * during the sync.
1266 	 */
1267 	vdev_config_dirty(spa->spa_root_vdev);
1268 
1269 	spa_config_exit(spa, SCL_ALL, FTAG);
1270 
1271 	txg_wait_synced(spa->spa_dsl_pool, 0);
1272 
1273 	/*
1274 	 * Sync the updated config cache.
1275 	 */
1276 	spa_config_sync(spa, B_FALSE, B_TRUE);
1277 
1278 	spa_close(spa, FTAG);
1279 
1280 	mutex_exit(&spa_namespace_lock);
1281 
1282 	return (0);
1283 }
1284 
1285 /*
1286  * Return the spa_t associated with given pool_guid, if it exists.  If
1287  * device_guid is non-zero, determine whether the pool exists *and* contains
1288  * a device with the specified device_guid.
1289  */
1290 spa_t *
1291 spa_by_guid(uint64_t pool_guid, uint64_t device_guid)
1292 {
1293 	spa_t *spa;
1294 	avl_tree_t *t = &spa_namespace_avl;
1295 
1296 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
1297 
1298 	for (spa = avl_first(t); spa != NULL; spa = AVL_NEXT(t, spa)) {
1299 		if (spa->spa_state == POOL_STATE_UNINITIALIZED)
1300 			continue;
1301 		if (spa->spa_root_vdev == NULL)
1302 			continue;
1303 		if (spa_guid(spa) == pool_guid) {
1304 			if (device_guid == 0)
1305 				break;
1306 
1307 			if (vdev_lookup_by_guid(spa->spa_root_vdev,
1308 			    device_guid) != NULL)
1309 				break;
1310 
1311 			/*
1312 			 * Check any devices we may be in the process of adding.
1313 			 */
1314 			if (spa->spa_pending_vdev) {
1315 				if (vdev_lookup_by_guid(spa->spa_pending_vdev,
1316 				    device_guid) != NULL)
1317 					break;
1318 			}
1319 		}
1320 	}
1321 
1322 	return (spa);
1323 }
1324 
1325 /*
1326  * Determine whether a pool with the given pool_guid exists.
1327  */
1328 boolean_t
1329 spa_guid_exists(uint64_t pool_guid, uint64_t device_guid)
1330 {
1331 	return (spa_by_guid(pool_guid, device_guid) != NULL);
1332 }
1333 
1334 char *
1335 spa_strdup(const char *s)
1336 {
1337 	size_t len;
1338 	char *new;
1339 
1340 	len = strlen(s);
1341 	new = kmem_alloc(len + 1, KM_SLEEP);
1342 	bcopy(s, new, len);
1343 	new[len] = '\0';
1344 
1345 	return (new);
1346 }
1347 
1348 void
1349 spa_strfree(char *s)
1350 {
1351 	kmem_free(s, strlen(s) + 1);
1352 }
1353 
1354 uint64_t
1355 spa_get_random(uint64_t range)
1356 {
1357 	uint64_t r;
1358 
1359 	ASSERT(range != 0);
1360 
1361 	(void) random_get_pseudo_bytes((void *)&r, sizeof (uint64_t));
1362 
1363 	return (r % range);
1364 }
1365 
1366 uint64_t
1367 spa_generate_guid(spa_t *spa)
1368 {
1369 	uint64_t guid = spa_get_random(-1ULL);
1370 
1371 	if (spa != NULL) {
1372 		while (guid == 0 || spa_guid_exists(spa_guid(spa), guid))
1373 			guid = spa_get_random(-1ULL);
1374 	} else {
1375 		while (guid == 0 || spa_guid_exists(guid, 0))
1376 			guid = spa_get_random(-1ULL);
1377 	}
1378 
1379 	return (guid);
1380 }
1381 
1382 void
1383 snprintf_blkptr(char *buf, size_t buflen, const blkptr_t *bp)
1384 {
1385 	char type[256];
1386 	char *checksum = NULL;
1387 	char *compress = NULL;
1388 
1389 	if (bp != NULL) {
1390 		if (BP_GET_TYPE(bp) & DMU_OT_NEWTYPE) {
1391 			dmu_object_byteswap_t bswap =
1392 			    DMU_OT_BYTESWAP(BP_GET_TYPE(bp));
1393 			(void) snprintf(type, sizeof (type), "bswap %s %s",
1394 			    DMU_OT_IS_METADATA(BP_GET_TYPE(bp)) ?
1395 			    "metadata" : "data",
1396 			    dmu_ot_byteswap[bswap].ob_name);
1397 		} else {
1398 			(void) strlcpy(type, dmu_ot[BP_GET_TYPE(bp)].ot_name,
1399 			    sizeof (type));
1400 		}
1401 		if (!BP_IS_EMBEDDED(bp)) {
1402 			checksum =
1403 			    zio_checksum_table[BP_GET_CHECKSUM(bp)].ci_name;
1404 		}
1405 		compress = zio_compress_table[BP_GET_COMPRESS(bp)].ci_name;
1406 	}
1407 
1408 	SNPRINTF_BLKPTR(snprintf, ' ', buf, buflen, bp, type, checksum,
1409 	    compress);
1410 }
1411 
1412 void
1413 spa_freeze(spa_t *spa)
1414 {
1415 	uint64_t freeze_txg = 0;
1416 
1417 	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
1418 	if (spa->spa_freeze_txg == UINT64_MAX) {
1419 		freeze_txg = spa_last_synced_txg(spa) + TXG_SIZE;
1420 		spa->spa_freeze_txg = freeze_txg;
1421 	}
1422 	spa_config_exit(spa, SCL_ALL, FTAG);
1423 	if (freeze_txg != 0)
1424 		txg_wait_synced(spa_get_dsl(spa), freeze_txg);
1425 }
1426 
1427 void
1428 zfs_panic_recover(const char *fmt, ...)
1429 {
1430 	va_list adx;
1431 
1432 	va_start(adx, fmt);
1433 	vcmn_err(zfs_recover ? CE_WARN : CE_PANIC, fmt, adx);
1434 	va_end(adx);
1435 }
1436 
1437 /*
1438  * This is a stripped-down version of strtoull, suitable only for converting
1439  * lowercase hexadecimal numbers that don't overflow.
1440  */
1441 uint64_t
1442 strtonum(const char *str, char **nptr)
1443 {
1444 	uint64_t val = 0;
1445 	char c;
1446 	int digit;
1447 
1448 	while ((c = *str) != '\0') {
1449 		if (c >= '0' && c <= '9')
1450 			digit = c - '0';
1451 		else if (c >= 'a' && c <= 'f')
1452 			digit = 10 + c - 'a';
1453 		else
1454 			break;
1455 
1456 		val *= 16;
1457 		val += digit;
1458 
1459 		str++;
1460 	}
1461 
1462 	if (nptr)
1463 		*nptr = (char *)str;
1464 
1465 	return (val);
1466 }
1467 
1468 /*
1469  * ==========================================================================
1470  * Accessor functions
1471  * ==========================================================================
1472  */
1473 
1474 boolean_t
1475 spa_shutting_down(spa_t *spa)
1476 {
1477 	return (spa->spa_async_suspended);
1478 }
1479 
1480 dsl_pool_t *
1481 spa_get_dsl(spa_t *spa)
1482 {
1483 	return (spa->spa_dsl_pool);
1484 }
1485 
1486 boolean_t
1487 spa_is_initializing(spa_t *spa)
1488 {
1489 	return (spa->spa_is_initializing);
1490 }
1491 
1492 blkptr_t *
1493 spa_get_rootblkptr(spa_t *spa)
1494 {
1495 	return (&spa->spa_ubsync.ub_rootbp);
1496 }
1497 
1498 void
1499 spa_set_rootblkptr(spa_t *spa, const blkptr_t *bp)
1500 {
1501 	spa->spa_uberblock.ub_rootbp = *bp;
1502 }
1503 
1504 void
1505 spa_altroot(spa_t *spa, char *buf, size_t buflen)
1506 {
1507 	if (spa->spa_root == NULL)
1508 		buf[0] = '\0';
1509 	else
1510 		(void) strncpy(buf, spa->spa_root, buflen);
1511 }
1512 
1513 int
1514 spa_sync_pass(spa_t *spa)
1515 {
1516 	return (spa->spa_sync_pass);
1517 }
1518 
1519 char *
1520 spa_name(spa_t *spa)
1521 {
1522 	return (spa->spa_name);
1523 }
1524 
1525 uint64_t
1526 spa_guid(spa_t *spa)
1527 {
1528 	dsl_pool_t *dp = spa_get_dsl(spa);
1529 	uint64_t guid;
1530 
1531 	/*
1532 	 * If we fail to parse the config during spa_load(), we can go through
1533 	 * the error path (which posts an ereport) and end up here with no root
1534 	 * vdev.  We stash the original pool guid in 'spa_config_guid' to handle
1535 	 * this case.
1536 	 */
1537 	if (spa->spa_root_vdev == NULL)
1538 		return (spa->spa_config_guid);
1539 
1540 	guid = spa->spa_last_synced_guid != 0 ?
1541 	    spa->spa_last_synced_guid : spa->spa_root_vdev->vdev_guid;
1542 
1543 	/*
1544 	 * Return the most recently synced out guid unless we're
1545 	 * in syncing context.
1546 	 */
1547 	if (dp && dsl_pool_sync_context(dp))
1548 		return (spa->spa_root_vdev->vdev_guid);
1549 	else
1550 		return (guid);
1551 }
1552 
1553 uint64_t
1554 spa_load_guid(spa_t *spa)
1555 {
1556 	/*
1557 	 * This is a GUID that exists solely as a reference for the
1558 	 * purposes of the arc.  It is generated at load time, and
1559 	 * is never written to persistent storage.
1560 	 */
1561 	return (spa->spa_load_guid);
1562 }
1563 
1564 uint64_t
1565 spa_last_synced_txg(spa_t *spa)
1566 {
1567 	return (spa->spa_ubsync.ub_txg);
1568 }
1569 
1570 uint64_t
1571 spa_first_txg(spa_t *spa)
1572 {
1573 	return (spa->spa_first_txg);
1574 }
1575 
1576 uint64_t
1577 spa_syncing_txg(spa_t *spa)
1578 {
1579 	return (spa->spa_syncing_txg);
1580 }
1581 
1582 pool_state_t
1583 spa_state(spa_t *spa)
1584 {
1585 	return (spa->spa_state);
1586 }
1587 
1588 spa_load_state_t
1589 spa_load_state(spa_t *spa)
1590 {
1591 	return (spa->spa_load_state);
1592 }
1593 
1594 uint64_t
1595 spa_freeze_txg(spa_t *spa)
1596 {
1597 	return (spa->spa_freeze_txg);
1598 }
1599 
1600 /* ARGSUSED */
1601 uint64_t
1602 spa_get_asize(spa_t *spa, uint64_t lsize)
1603 {
1604 	return (lsize * spa_asize_inflation);
1605 }
1606 
1607 /*
1608  * Return the amount of slop space in bytes.  It is 1/32 of the pool (3.2%),
1609  * or at least 32MB.
1610  *
1611  * See the comment above spa_slop_shift for details.
1612  */
1613 uint64_t
1614 spa_get_slop_space(spa_t *spa) {
1615 	uint64_t space = spa_get_dspace(spa);
1616 	return (MAX(space >> spa_slop_shift, SPA_MINDEVSIZE >> 1));
1617 }
1618 
1619 uint64_t
1620 spa_get_dspace(spa_t *spa)
1621 {
1622 	return (spa->spa_dspace);
1623 }
1624 
1625 void
1626 spa_update_dspace(spa_t *spa)
1627 {
1628 	spa->spa_dspace = metaslab_class_get_dspace(spa_normal_class(spa)) +
1629 	    ddt_get_dedup_dspace(spa);
1630 }
1631 
1632 /*
1633  * Return the failure mode that has been set to this pool. The default
1634  * behavior will be to block all I/Os when a complete failure occurs.
1635  */
1636 uint8_t
1637 spa_get_failmode(spa_t *spa)
1638 {
1639 	return (spa->spa_failmode);
1640 }
1641 
1642 boolean_t
1643 spa_suspended(spa_t *spa)
1644 {
1645 	return (spa->spa_suspended);
1646 }
1647 
1648 uint64_t
1649 spa_version(spa_t *spa)
1650 {
1651 	return (spa->spa_ubsync.ub_version);
1652 }
1653 
1654 boolean_t
1655 spa_deflate(spa_t *spa)
1656 {
1657 	return (spa->spa_deflate);
1658 }
1659 
1660 metaslab_class_t *
1661 spa_normal_class(spa_t *spa)
1662 {
1663 	return (spa->spa_normal_class);
1664 }
1665 
1666 metaslab_class_t *
1667 spa_log_class(spa_t *spa)
1668 {
1669 	return (spa->spa_log_class);
1670 }
1671 
1672 int
1673 spa_max_replication(spa_t *spa)
1674 {
1675 	/*
1676 	 * As of SPA_VERSION == SPA_VERSION_DITTO_BLOCKS, we are able to
1677 	 * handle BPs with more than one DVA allocated.  Set our max
1678 	 * replication level accordingly.
1679 	 */
1680 	if (spa_version(spa) < SPA_VERSION_DITTO_BLOCKS)
1681 		return (1);
1682 	return (MIN(SPA_DVAS_PER_BP, spa_max_replication_override));
1683 }
1684 
1685 int
1686 spa_prev_software_version(spa_t *spa)
1687 {
1688 	return (spa->spa_prev_software_version);
1689 }
1690 
1691 uint64_t
1692 spa_deadman_synctime(spa_t *spa)
1693 {
1694 	return (spa->spa_deadman_synctime);
1695 }
1696 
1697 uint64_t
1698 dva_get_dsize_sync(spa_t *spa, const dva_t *dva)
1699 {
1700 	uint64_t asize = DVA_GET_ASIZE(dva);
1701 	uint64_t dsize = asize;
1702 
1703 	ASSERT(spa_config_held(spa, SCL_ALL, RW_READER) != 0);
1704 
1705 	if (asize != 0 && spa->spa_deflate) {
1706 		vdev_t *vd = vdev_lookup_top(spa, DVA_GET_VDEV(dva));
1707 		dsize = (asize >> SPA_MINBLOCKSHIFT) * vd->vdev_deflate_ratio;
1708 	}
1709 
1710 	return (dsize);
1711 }
1712 
1713 uint64_t
1714 bp_get_dsize_sync(spa_t *spa, const blkptr_t *bp)
1715 {
1716 	uint64_t dsize = 0;
1717 
1718 	for (int d = 0; d < BP_GET_NDVAS(bp); d++)
1719 		dsize += dva_get_dsize_sync(spa, &bp->blk_dva[d]);
1720 
1721 	return (dsize);
1722 }
1723 
1724 uint64_t
1725 bp_get_dsize(spa_t *spa, const blkptr_t *bp)
1726 {
1727 	uint64_t dsize = 0;
1728 
1729 	spa_config_enter(spa, SCL_VDEV, FTAG, RW_READER);
1730 
1731 	for (int d = 0; d < BP_GET_NDVAS(bp); d++)
1732 		dsize += dva_get_dsize_sync(spa, &bp->blk_dva[d]);
1733 
1734 	spa_config_exit(spa, SCL_VDEV, FTAG);
1735 
1736 	return (dsize);
1737 }
1738 
1739 /*
1740  * ==========================================================================
1741  * Initialization and Termination
1742  * ==========================================================================
1743  */
1744 
1745 static int
1746 spa_name_compare(const void *a1, const void *a2)
1747 {
1748 	const spa_t *s1 = a1;
1749 	const spa_t *s2 = a2;
1750 	int s;
1751 
1752 	s = strcmp(s1->spa_name, s2->spa_name);
1753 	if (s > 0)
1754 		return (1);
1755 	if (s < 0)
1756 		return (-1);
1757 	return (0);
1758 }
1759 
1760 int
1761 spa_busy(void)
1762 {
1763 	return (spa_active_count);
1764 }
1765 
1766 void
1767 spa_boot_init()
1768 {
1769 	spa_config_load();
1770 }
1771 
1772 void
1773 spa_init(int mode)
1774 {
1775 	mutex_init(&spa_namespace_lock, NULL, MUTEX_DEFAULT, NULL);
1776 	mutex_init(&spa_spare_lock, NULL, MUTEX_DEFAULT, NULL);
1777 	mutex_init(&spa_l2cache_lock, NULL, MUTEX_DEFAULT, NULL);
1778 	cv_init(&spa_namespace_cv, NULL, CV_DEFAULT, NULL);
1779 
1780 	avl_create(&spa_namespace_avl, spa_name_compare, sizeof (spa_t),
1781 	    offsetof(spa_t, spa_avl));
1782 
1783 	avl_create(&spa_spare_avl, spa_spare_compare, sizeof (spa_aux_t),
1784 	    offsetof(spa_aux_t, aux_avl));
1785 
1786 	avl_create(&spa_l2cache_avl, spa_l2cache_compare, sizeof (spa_aux_t),
1787 	    offsetof(spa_aux_t, aux_avl));
1788 
1789 	spa_mode_global = mode;
1790 
1791 #ifdef _KERNEL
1792 	spa_arch_init();
1793 #else
1794 	if (spa_mode_global != FREAD && dprintf_find_string("watch")) {
1795 		arc_procfd = open("/proc/self/ctl", O_WRONLY);
1796 		if (arc_procfd == -1) {
1797 			perror("could not enable watchpoints: "
1798 			    "opening /proc/self/ctl failed: ");
1799 		} else {
1800 			arc_watch = B_TRUE;
1801 		}
1802 	}
1803 #endif
1804 
1805 	refcount_init();
1806 	unique_init();
1807 	range_tree_init();
1808 	zio_init();
1809 	dmu_init();
1810 	zil_init();
1811 	vdev_cache_stat_init();
1812 	zfs_prop_init();
1813 	zpool_prop_init();
1814 	zpool_feature_init();
1815 	spa_config_load();
1816 	l2arc_start();
1817 }
1818 
1819 void
1820 spa_fini(void)
1821 {
1822 	l2arc_stop();
1823 
1824 	spa_evict_all();
1825 
1826 	vdev_cache_stat_fini();
1827 	zil_fini();
1828 	dmu_fini();
1829 	zio_fini();
1830 	range_tree_fini();
1831 	unique_fini();
1832 	refcount_fini();
1833 
1834 	avl_destroy(&spa_namespace_avl);
1835 	avl_destroy(&spa_spare_avl);
1836 	avl_destroy(&spa_l2cache_avl);
1837 
1838 	cv_destroy(&spa_namespace_cv);
1839 	mutex_destroy(&spa_namespace_lock);
1840 	mutex_destroy(&spa_spare_lock);
1841 	mutex_destroy(&spa_l2cache_lock);
1842 }
1843 
1844 /*
1845  * Return whether this pool has slogs. No locking needed.
1846  * It's not a problem if the wrong answer is returned as it's only for
1847  * performance and not correctness
1848  */
1849 boolean_t
1850 spa_has_slogs(spa_t *spa)
1851 {
1852 	return (spa->spa_log_class->mc_rotor != NULL);
1853 }
1854 
1855 spa_log_state_t
1856 spa_get_log_state(spa_t *spa)
1857 {
1858 	return (spa->spa_log_state);
1859 }
1860 
1861 void
1862 spa_set_log_state(spa_t *spa, spa_log_state_t state)
1863 {
1864 	spa->spa_log_state = state;
1865 }
1866 
1867 boolean_t
1868 spa_is_root(spa_t *spa)
1869 {
1870 	return (spa->spa_is_root);
1871 }
1872 
1873 boolean_t
1874 spa_writeable(spa_t *spa)
1875 {
1876 	return (!!(spa->spa_mode & FWRITE));
1877 }
1878 
1879 /*
1880  * Returns true if there is a pending sync task in any of the current
1881  * syncing txg, the current quiescing txg, or the current open txg.
1882  */
1883 boolean_t
1884 spa_has_pending_synctask(spa_t *spa)
1885 {
1886 	return (!txg_all_lists_empty(&spa->spa_dsl_pool->dp_sync_tasks));
1887 }
1888 
1889 int
1890 spa_mode(spa_t *spa)
1891 {
1892 	return (spa->spa_mode);
1893 }
1894 
1895 uint64_t
1896 spa_bootfs(spa_t *spa)
1897 {
1898 	return (spa->spa_bootfs);
1899 }
1900 
1901 uint64_t
1902 spa_delegation(spa_t *spa)
1903 {
1904 	return (spa->spa_delegation);
1905 }
1906 
1907 objset_t *
1908 spa_meta_objset(spa_t *spa)
1909 {
1910 	return (spa->spa_meta_objset);
1911 }
1912 
1913 enum zio_checksum
1914 spa_dedup_checksum(spa_t *spa)
1915 {
1916 	return (spa->spa_dedup_checksum);
1917 }
1918 
1919 /*
1920  * Reset pool scan stat per scan pass (or reboot).
1921  */
1922 void
1923 spa_scan_stat_init(spa_t *spa)
1924 {
1925 	/* data not stored on disk */
1926 	spa->spa_scan_pass_start = gethrestime_sec();
1927 	spa->spa_scan_pass_exam = 0;
1928 	vdev_scan_stat_init(spa->spa_root_vdev);
1929 }
1930 
1931 /*
1932  * Get scan stats for zpool status reports
1933  */
1934 int
1935 spa_scan_get_stats(spa_t *spa, pool_scan_stat_t *ps)
1936 {
1937 	dsl_scan_t *scn = spa->spa_dsl_pool ? spa->spa_dsl_pool->dp_scan : NULL;
1938 
1939 	if (scn == NULL || scn->scn_phys.scn_func == POOL_SCAN_NONE)
1940 		return (SET_ERROR(ENOENT));
1941 	bzero(ps, sizeof (pool_scan_stat_t));
1942 
1943 	/* data stored on disk */
1944 	ps->pss_func = scn->scn_phys.scn_func;
1945 	ps->pss_start_time = scn->scn_phys.scn_start_time;
1946 	ps->pss_end_time = scn->scn_phys.scn_end_time;
1947 	ps->pss_to_examine = scn->scn_phys.scn_to_examine;
1948 	ps->pss_examined = scn->scn_phys.scn_examined;
1949 	ps->pss_to_process = scn->scn_phys.scn_to_process;
1950 	ps->pss_processed = scn->scn_phys.scn_processed;
1951 	ps->pss_errors = scn->scn_phys.scn_errors;
1952 	ps->pss_state = scn->scn_phys.scn_state;
1953 
1954 	/* data not stored on disk */
1955 	ps->pss_pass_start = spa->spa_scan_pass_start;
1956 	ps->pss_pass_exam = spa->spa_scan_pass_exam;
1957 
1958 	return (0);
1959 }
1960 
1961 boolean_t
1962 spa_debug_enabled(spa_t *spa)
1963 {
1964 	return (spa->spa_debug);
1965 }
1966 
1967 int
1968 spa_maxblocksize(spa_t *spa)
1969 {
1970 	if (spa_feature_is_enabled(spa, SPA_FEATURE_LARGE_BLOCKS))
1971 		return (SPA_MAXBLOCKSIZE);
1972 	else
1973 		return (SPA_OLD_MAXBLOCKSIZE);
1974 }
1975