Please welcome ZFS - The last word in file systems.

ZFS file system was ported from OpenSolaris operating system. The code in under
CDDL license.

I'd like to thank all SUN developers that created this great piece of software.

Supported by:	Wheel LTD (http://www.wheel.pl/)
Supported by:	The FreeBSD Foundation (http://www.freebsdfoundation.org/)
Supported by:	Sentex (http://www.sentex.net/)

1 files changed, 1126 insertions, 0 deletions

diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_misc.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_misc.c
new file mode 100644
index 0000000..1de1e5a
--- /dev/null
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_misc.c
@@ -0,0 +1,1126 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#pragma ident	"%Z%%M%	%I%	%E% SMI"
+
+#include <sys/zfs_context.h>
+#include <sys/spa_impl.h>
+#include <sys/zio.h>
+#include <sys/zio_checksum.h>
+#include <sys/zio_compress.h>
+#include <sys/dmu.h>
+#include <sys/dmu_tx.h>
+#include <sys/zap.h>
+#include <sys/zil.h>
+#include <sys/vdev_impl.h>
+#include <sys/metaslab.h>
+#include <sys/uberblock_impl.h>
+#include <sys/txg.h>
+#include <sys/avl.h>
+#include <sys/unique.h>
+#include <sys/dsl_pool.h>
+#include <sys/dsl_dir.h>
+#include <sys/dsl_prop.h>
+#include <sys/fs/zfs.h>
+
+/*
+ * SPA locking
+ *
+ * There are four basic locks for managing spa_t structures:
+ *
+ * spa_namespace_lock (global mutex)
+ *
+ *	This lock must be acquired to do any of the following:
+ *
+ *		- Lookup a spa_t by name
+ *		- Add or remove a spa_t from the namespace
+ *		- Increase spa_refcount from non-zero
+ *		- Check if spa_refcount is zero
+ *		- Rename a spa_t
+ *		- add/remove/attach/detach devices
+ *		- Held for the duration of create/destroy/import/export
+ *
+ *	It does not need to handle recursion.  A create or destroy may
+ *	reference objects (files or zvols) in other pools, but by
+ *	definition they must have an existing reference, and will never need
+ *	to lookup a spa_t by name.
+ *
+ * spa_refcount (per-spa refcount_t protected by mutex)
+ *
+ *	This reference count keep track of any active users of the spa_t.  The
+ *	spa_t cannot be destroyed or freed while this is non-zero.  Internally,
+ *	the refcount is never really 'zero' - opening a pool implicitly keeps
+ *	some references in the DMU.  Internally we check against SPA_MINREF, but
+ *	present the image of a zero/non-zero value to consumers.
+ *
+ * spa_config_lock (per-spa crazy rwlock)
+ *
+ *	This SPA special is a recursive rwlock, capable of being acquired from
+ *	asynchronous threads.  It has protects the spa_t from config changes,
+ *	and must be held in the following circumstances:
+ *
+ *		- RW_READER to perform I/O to the spa
+ *		- RW_WRITER to change the vdev config
+ *
+ * spa_config_cache_lock (per-spa mutex)
+ *
+ *	This mutex prevents the spa_config nvlist from being updated.  No
+ *      other locks are required to obtain this lock, although implicitly you
+ *      must have the namespace lock or non-zero refcount to have any kind
+ *      of spa_t pointer at all.
+ *
+ * The locking order is fairly straightforward:
+ *
+ *		spa_namespace_lock	->	spa_refcount
+ *
+ *	The namespace lock must be acquired to increase the refcount from 0
+ *	or to check if it is zero.
+ *
+ *		spa_refcount		->	spa_config_lock
+ *
+ *	There must be at least one valid reference on the spa_t to acquire
+ *	the config lock.
+ *
+ *		spa_namespace_lock	->	spa_config_lock
+ *
+ *	The namespace lock must always be taken before the config lock.
+ *
+ *
+ * The spa_namespace_lock and spa_config_cache_lock can be acquired directly and
+ * are globally visible.
+ *
+ * The namespace is manipulated using the following functions, all which require
+ * the spa_namespace_lock to be held.
+ *
+ *	spa_lookup()		Lookup a spa_t by name.
+ *
+ *	spa_add()		Create a new spa_t in the namespace.
+ *
+ *	spa_remove()		Remove a spa_t from the namespace.  This also
+ *				frees up any memory associated with the spa_t.
+ *
+ *	spa_next()		Returns the next spa_t in the system, or the
+ *				first if NULL is passed.
+ *
+ *	spa_evict_all()		Shutdown and remove all spa_t structures in
+ *				the system.
+ *
+ *	spa_guid_exists()	Determine whether a pool/device guid exists.
+ *
+ * The spa_refcount is manipulated using the following functions:
+ *
+ *	spa_open_ref()		Adds a reference to the given spa_t.  Must be
+ *				called with spa_namespace_lock held if the
+ *				refcount is currently zero.
+ *
+ *	spa_close()		Remove a reference from the spa_t.  This will
+ *				not free the spa_t or remove it from the
+ *				namespace.  No locking is required.
+ *
+ *	spa_refcount_zero()	Returns true if the refcount is currently
+ *				zero.  Must be called with spa_namespace_lock
+ *				held.
+ *
+ * The spa_config_lock is manipulated using the following functions:
+ *
+ *	spa_config_enter()	Acquire the config lock as RW_READER or
+ *				RW_WRITER.  At least one reference on the spa_t
+ *				must exist.
+ *
+ *	spa_config_exit()	Release the config lock.
+ *
+ *	spa_config_held()	Returns true if the config lock is currently
+ *				held in the given state.
+ *
+ * The vdev configuration is protected by spa_vdev_enter() / spa_vdev_exit().
+ *
+ *	spa_vdev_enter()	Acquire the namespace lock and the config lock
+ *				for writing.
+ *
+ *	spa_vdev_exit()		Release the config lock, wait for all I/O
+ *				to complete, sync the updated configs to the
+ *				cache, and release the namespace lock.
+ *
+ * The spa_name() function also requires either the spa_namespace_lock
+ * or the spa_config_lock, as both are needed to do a rename.  spa_rename() is
+ * also implemented within this file since is requires manipulation of the
+ * namespace.
+ */
+
+static avl_tree_t spa_namespace_avl;
+kmutex_t spa_namespace_lock;
+static kcondvar_t spa_namespace_cv;
+static int spa_active_count;
+int spa_max_replication_override = SPA_DVAS_PER_BP;
+
+static kmutex_t spa_spare_lock;
+static avl_tree_t spa_spare_avl;
+
+kmem_cache_t *spa_buffer_pool;
+int spa_mode;
+
+#ifdef ZFS_DEBUG
+int zfs_flags = ~0;
+#else
+int zfs_flags = 0;
+#endif
+
+/*
+ * zfs_recover can be set to nonzero to attempt to recover from
+ * otherwise-fatal errors, typically caused by on-disk corruption.  When
+ * set, calls to zfs_panic_recover() will turn into warning messages.
+ */
+int zfs_recover = 0;
+
+#define	SPA_MINREF	5	/* spa_refcnt for an open-but-idle pool */
+
+/*
+ * ==========================================================================
+ * SPA namespace functions
+ * ==========================================================================
+ */
+
+/*
+ * Lookup the named spa_t in the AVL tree.  The spa_namespace_lock must be held.
+ * Returns NULL if no matching spa_t is found.
+ */
+spa_t *
+spa_lookup(const char *name)
+{
+	spa_t search, *spa;
+	avl_index_t where;
+
+	ASSERT(MUTEX_HELD(&spa_namespace_lock));
+
+	search.spa_name = (char *)name;
+	spa = avl_find(&spa_namespace_avl, &search, &where);
+
+	return (spa);
+}
+
+/*
+ * Create an uninitialized spa_t with the given name.  Requires
+ * spa_namespace_lock.  The caller must ensure that the spa_t doesn't already
+ * exist by calling spa_lookup() first.
+ */
+spa_t *
+spa_add(const char *name, const char *altroot)
+{
+	spa_t *spa;
+
+	ASSERT(MUTEX_HELD(&spa_namespace_lock));
+
+	spa = kmem_zalloc(sizeof (spa_t), KM_SLEEP);
+
+	spa->spa_name = spa_strdup(name);
+	spa->spa_state = POOL_STATE_UNINITIALIZED;
+	spa->spa_freeze_txg = UINT64_MAX;
+	spa->spa_final_txg = UINT64_MAX;
+
+	mutex_init(&spa->spa_config_cache_lock, NULL, MUTEX_DEFAULT, NULL);
+	mutex_init(&spa->spa_async_lock, NULL, MUTEX_DEFAULT, NULL);
+	mutex_init(&spa->spa_scrub_lock, NULL, MUTEX_DEFAULT, NULL);
+
+	cv_init(&spa->spa_scrub_cv, NULL, CV_DEFAULT, NULL);
+	cv_init(&spa->spa_scrub_io_cv, NULL, CV_DEFAULT, NULL);
+	cv_init(&spa->spa_async_cv, NULL, CV_DEFAULT, NULL);
+
+	refcount_create(&spa->spa_refcount);
+	refcount_create(&spa->spa_config_lock.scl_count);
+
+	avl_add(&spa_namespace_avl, spa);
+
+	/*
+	 * Set the alternate root, if there is one.
+	 */
+	if (altroot) {
+		spa->spa_root = spa_strdup(altroot);
+		spa_active_count++;
+	}
+
+	return (spa);
+}
+
+/*
+ * Removes a spa_t from the namespace, freeing up any memory used.  Requires
+ * spa_namespace_lock.  This is called only after the spa_t has been closed and
+ * deactivated.
+ */
+void
+spa_remove(spa_t *spa)
+{
+	ASSERT(MUTEX_HELD(&spa_namespace_lock));
+	ASSERT(spa->spa_state == POOL_STATE_UNINITIALIZED);
+	ASSERT(spa->spa_scrub_thread == NULL);
+
+	avl_remove(&spa_namespace_avl, spa);
+	cv_broadcast(&spa_namespace_cv);
+
+	if (spa->spa_root) {
+		spa_strfree(spa->spa_root);
+		spa_active_count--;
+	}
+
+	if (spa->spa_name)
+		spa_strfree(spa->spa_name);
+
+	spa_config_set(spa, NULL);
+
+	refcount_destroy(&spa->spa_refcount);
+	refcount_destroy(&spa->spa_config_lock.scl_count);
+
+	cv_destroy(&spa->spa_async_cv);
+	cv_destroy(&spa->spa_scrub_io_cv);
+	cv_destroy(&spa->spa_scrub_cv);
+
+	mutex_destroy(&spa->spa_scrub_lock);
+	mutex_destroy(&spa->spa_async_lock);
+	mutex_destroy(&spa->spa_config_cache_lock);
+
+	kmem_free(spa, sizeof (spa_t));
+}
+
+/*
+ * Given a pool, return the next pool in the namespace, or NULL if there is
+ * none.  If 'prev' is NULL, return the first pool.
+ */
+spa_t *
+spa_next(spa_t *prev)
+{
+	ASSERT(MUTEX_HELD(&spa_namespace_lock));
+
+	if (prev)
+		return (AVL_NEXT(&spa_namespace_avl, prev));
+	else
+		return (avl_first(&spa_namespace_avl));
+}
+
+/*
+ * ==========================================================================
+ * SPA refcount functions
+ * ==========================================================================
+ */
+
+/*
+ * Add a reference to the given spa_t.  Must have at least one reference, or
+ * have the namespace lock held.
+ */
+void
+spa_open_ref(spa_t *spa, void *tag)
+{
+	ASSERT(refcount_count(&spa->spa_refcount) > SPA_MINREF ||
+	    MUTEX_HELD(&spa_namespace_lock));
+
+	(void) refcount_add(&spa->spa_refcount, tag);
+}
+
+/*
+ * Remove a reference to the given spa_t.  Must have at least one reference, or
+ * have the namespace lock held.
+ */
+void
+spa_close(spa_t *spa, void *tag)
+{
+	ASSERT(refcount_count(&spa->spa_refcount) > SPA_MINREF ||
+	    MUTEX_HELD(&spa_namespace_lock));
+
+	(void) refcount_remove(&spa->spa_refcount, tag);
+}
+
+/*
+ * Check to see if the spa refcount is zero.  Must be called with
+ * spa_namespace_lock held.  We really compare against SPA_MINREF, which is the
+ * number of references acquired when opening a pool
+ */
+boolean_t
+spa_refcount_zero(spa_t *spa)
+{
+	ASSERT(MUTEX_HELD(&spa_namespace_lock));
+
+	return (refcount_count(&spa->spa_refcount) == SPA_MINREF);
+}
+
+/*
+ * ==========================================================================
+ * SPA spare tracking
+ * ==========================================================================
+ */
+
+/*
+ * Spares are tracked globally due to the following constraints:
+ *
+ * 	- A spare may be part of multiple pools.
+ * 	- A spare may be added to a pool even if it's actively in use within
+ *	  another pool.
+ * 	- A spare in use in any pool can only be the source of a replacement if
+ *	  the target is a spare in the same pool.
+ *
+ * We keep track of all spares on the system through the use of a reference
+ * counted AVL tree.  When a vdev is added as a spare, or used as a replacement
+ * spare, then we bump the reference count in the AVL tree.  In addition, we set
+ * the 'vdev_isspare' member to indicate that the device is a spare (active or
+ * inactive).  When a spare is made active (used to replace a device in the
+ * pool), we also keep track of which pool its been made a part of.
+ *
+ * The 'spa_spare_lock' protects the AVL tree.  These functions are normally
+ * called under the spa_namespace lock as part of vdev reconfiguration.  The
+ * separate spare lock exists for the status query path, which does not need to
+ * be completely consistent with respect to other vdev configuration changes.
+ */
+
+typedef struct spa_spare {
+	uint64_t	spare_guid;
+	uint64_t	spare_pool;
+	avl_node_t	spare_avl;
+	int		spare_count;
+} spa_spare_t;
+
+static int
+spa_spare_compare(const void *a, const void *b)
+{
+	const spa_spare_t *sa = a;
+	const spa_spare_t *sb = b;
+
+	if (sa->spare_guid < sb->spare_guid)
+		return (-1);
+	else if (sa->spare_guid > sb->spare_guid)
+		return (1);
+	else
+		return (0);
+}
+
+void
+spa_spare_add(vdev_t *vd)
+{
+	avl_index_t where;
+	spa_spare_t search;
+	spa_spare_t *spare;
+
+	mutex_enter(&spa_spare_lock);
+	ASSERT(!vd->vdev_isspare);
+
+	search.spare_guid = vd->vdev_guid;
+	if ((spare = avl_find(&spa_spare_avl, &search, &where)) != NULL) {
+		spare->spare_count++;
+	} else {
+		spare = kmem_zalloc(sizeof (spa_spare_t), KM_SLEEP);
+		spare->spare_guid = vd->vdev_guid;
+		spare->spare_count = 1;
+		avl_insert(&spa_spare_avl, spare, where);
+	}
+	vd->vdev_isspare = B_TRUE;
+
+	mutex_exit(&spa_spare_lock);
+}
+
+void
+spa_spare_remove(vdev_t *vd)
+{
+	spa_spare_t search;
+	spa_spare_t *spare;
+	avl_index_t where;
+
+	mutex_enter(&spa_spare_lock);
+
+	search.spare_guid = vd->vdev_guid;
+	spare = avl_find(&spa_spare_avl, &search, &where);
+
+	ASSERT(vd->vdev_isspare);
+	ASSERT(spare != NULL);
+
+	if (--spare->spare_count == 0) {
+		avl_remove(&spa_spare_avl, spare);
+		kmem_free(spare, sizeof (spa_spare_t));
+	} else if (spare->spare_pool == spa_guid(vd->vdev_spa)) {
+		spare->spare_pool = 0ULL;
+	}
+
+	vd->vdev_isspare = B_FALSE;
+	mutex_exit(&spa_spare_lock);
+}
+
+boolean_t
+spa_spare_exists(uint64_t guid, uint64_t *pool)
+{
+	spa_spare_t search, *found;
+	avl_index_t where;
+
+	mutex_enter(&spa_spare_lock);
+
+	search.spare_guid = guid;
+	found = avl_find(&spa_spare_avl, &search, &where);
+
+	if (pool) {
+		if (found)
+			*pool = found->spare_pool;
+		else
+			*pool = 0ULL;
+	}
+
+	mutex_exit(&spa_spare_lock);
+
+	return (found != NULL);
+}
+
+void
+spa_spare_activate(vdev_t *vd)
+{
+	spa_spare_t search, *found;
+	avl_index_t where;
+
+	mutex_enter(&spa_spare_lock);
+	ASSERT(vd->vdev_isspare);
+
+	search.spare_guid = vd->vdev_guid;
+	found = avl_find(&spa_spare_avl, &search, &where);
+	ASSERT(found != NULL);
+	ASSERT(found->spare_pool == 0ULL);
+
+	found->spare_pool = spa_guid(vd->vdev_spa);
+	mutex_exit(&spa_spare_lock);
+}
+
+/*
+ * ==========================================================================
+ * SPA config locking
+ * ==========================================================================
+ */
+
+/*
+ * Acquire the config lock.  The config lock is a special rwlock that allows for
+ * recursive enters.  Because these enters come from the same thread as well as
+ * asynchronous threads working on behalf of the owner, we must unilaterally
+ * allow all reads access as long at least one reader is held (even if a write
+ * is requested).  This has the side effect of write starvation, but write locks
+ * are extremely rare, and a solution to this problem would be significantly
+ * more complex (if even possible).
+ *
+ * We would like to assert that the namespace lock isn't held, but this is a
+ * valid use during create.
+ */
+void
+spa_config_enter(spa_t *spa, krw_t rw, void *tag)
+{
+	spa_config_lock_t *scl = &spa->spa_config_lock;
+
+	mutex_enter(&scl->scl_lock);
+
+	if (scl->scl_writer != curthread) {
+		if (rw == RW_READER) {
+			while (scl->scl_writer != NULL)
+				cv_wait(&scl->scl_cv, &scl->scl_lock);
+		} else {
+			while (scl->scl_writer != NULL ||
+			    !refcount_is_zero(&scl->scl_count))
+				cv_wait(&scl->scl_cv, &scl->scl_lock);
+			scl->scl_writer = curthread;
+		}
+	}
+
+	(void) refcount_add(&scl->scl_count, tag);
+
+	mutex_exit(&scl->scl_lock);
+}
+
+/*
+ * Release the spa config lock, notifying any waiters in the process.
+ */
+void
+spa_config_exit(spa_t *spa, void *tag)
+{
+	spa_config_lock_t *scl = &spa->spa_config_lock;
+
+	mutex_enter(&scl->scl_lock);
+
+	ASSERT(!refcount_is_zero(&scl->scl_count));
+	if (refcount_remove(&scl->scl_count, tag) == 0) {
+		cv_broadcast(&scl->scl_cv);
+		scl->scl_writer = NULL;  /* OK in either case */
+	}
+
+	mutex_exit(&scl->scl_lock);
+}
+
+/*
+ * Returns true if the config lock is held in the given manner.
+ */
+boolean_t
+spa_config_held(spa_t *spa, krw_t rw)
+{
+	spa_config_lock_t *scl = &spa->spa_config_lock;
+	boolean_t held;
+
+	mutex_enter(&scl->scl_lock);
+	if (rw == RW_WRITER)
+		held = (scl->scl_writer == curthread);
+	else
+		held = !refcount_is_zero(&scl->scl_count);
+	mutex_exit(&scl->scl_lock);
+
+	return (held);
+}
+
+/*
+ * ==========================================================================
+ * SPA vdev locking
+ * ==========================================================================
+ */
+
+/*
+ * Lock the given spa_t for the purpose of adding or removing a vdev.
+ * Grabs the global spa_namespace_lock plus the spa config lock for writing.
+ * It returns the next transaction group for the spa_t.
+ */
+uint64_t
+spa_vdev_enter(spa_t *spa)
+{
+	/*
+	 * Suspend scrub activity while we mess with the config.
+	 */
+	spa_scrub_suspend(spa);
+
+	mutex_enter(&spa_namespace_lock);
+
+	spa_config_enter(spa, RW_WRITER, spa);
+
+	return (spa_last_synced_txg(spa) + 1);
+}
+
+/*
+ * Unlock the spa_t after adding or removing a vdev.  Besides undoing the
+ * locking of spa_vdev_enter(), we also want make sure the transactions have
+ * synced to disk, and then update the global configuration cache with the new
+ * information.
+ */
+int
+spa_vdev_exit(spa_t *spa, vdev_t *vd, uint64_t txg, int error)
+{
+	int config_changed = B_FALSE;
+
+	ASSERT(txg > spa_last_synced_txg(spa));
+
+	/*
+	 * Reassess the DTLs.
+	 */
+	vdev_dtl_reassess(spa->spa_root_vdev, 0, 0, B_FALSE);
+
+	/*
+	 * If the config changed, notify the scrub thread that it must restart.
+	 */
+	if (error == 0 && !list_is_empty(&spa->spa_dirty_list)) {
+		config_changed = B_TRUE;
+		spa_scrub_restart(spa, txg);
+	}
+
+	spa_config_exit(spa, spa);
+
+	/*
+	 * Allow scrubbing to resume.
+	 */
+	spa_scrub_resume(spa);
+
+	/*
+	 * Note: this txg_wait_synced() is important because it ensures
+	 * that there won't be more than one config change per txg.
+	 * This allows us to use the txg as the generation number.
+	 */
+	if (error == 0)
+		txg_wait_synced(spa->spa_dsl_pool, txg);
+
+	if (vd != NULL) {
+		ASSERT(!vd->vdev_detached || vd->vdev_dtl.smo_object == 0);
+		vdev_free(vd);
+	}
+
+	/*
+	 * If the config changed, update the config cache.
+	 */
+	if (config_changed)
+		spa_config_sync();
+
+	mutex_exit(&spa_namespace_lock);
+
+	return (error);
+}
+
+/*
+ * ==========================================================================
+ * Miscellaneous functions
+ * ==========================================================================
+ */
+
+/*
+ * Rename a spa_t.
+ */
+int
+spa_rename(const char *name, const char *newname)
+{
+	spa_t *spa;
+	int err;
+
+	/*
+	 * Lookup the spa_t and grab the config lock for writing.  We need to
+	 * actually open the pool so that we can sync out the necessary labels.
+	 * It's OK to call spa_open() with the namespace lock held because we
+	 * allow recursive calls for other reasons.
+	 */
+	mutex_enter(&spa_namespace_lock);
+	if ((err = spa_open(name, &spa, FTAG)) != 0) {
+		mutex_exit(&spa_namespace_lock);
+		return (err);
+	}
+
+	spa_config_enter(spa, RW_WRITER, FTAG);
+
+	avl_remove(&spa_namespace_avl, spa);
+	spa_strfree(spa->spa_name);
+	spa->spa_name = spa_strdup(newname);
+	avl_add(&spa_namespace_avl, spa);
+
+	/*
+	 * Sync all labels to disk with the new names by marking the root vdev
+	 * dirty and waiting for it to sync.  It will pick up the new pool name
+	 * during the sync.
+	 */
+	vdev_config_dirty(spa->spa_root_vdev);
+
+	spa_config_exit(spa, FTAG);
+
+	txg_wait_synced(spa->spa_dsl_pool, 0);
+
+	/*
+	 * Sync the updated config cache.
+	 */
+	spa_config_sync();
+
+	spa_close(spa, FTAG);
+
+	mutex_exit(&spa_namespace_lock);
+
+	return (0);
+}
+
+
+/*
+ * Determine whether a pool with given pool_guid exists.  If device_guid is
+ * non-zero, determine whether the pool exists *and* contains a device with the
+ * specified device_guid.
+ */
+boolean_t
+spa_guid_exists(uint64_t pool_guid, uint64_t device_guid)
+{
+	spa_t *spa;
+	avl_tree_t *t = &spa_namespace_avl;
+
+	ASSERT(MUTEX_HELD(&spa_namespace_lock));
+
+	for (spa = avl_first(t); spa != NULL; spa = AVL_NEXT(t, spa)) {
+		if (spa->spa_state == POOL_STATE_UNINITIALIZED)
+			continue;
+		if (spa->spa_root_vdev == NULL)
+			continue;
+		if (spa_guid(spa) == pool_guid) {
+			if (device_guid == 0)
+				break;
+
+			if (vdev_lookup_by_guid(spa->spa_root_vdev,
+			    device_guid) != NULL)
+				break;
+
+			/*
+			 * Check any devices we may in the process of adding.
+			 */
+			if (spa->spa_pending_vdev) {
+				if (vdev_lookup_by_guid(spa->spa_pending_vdev,
+				    device_guid) != NULL)
+					break;
+			}
+		}
+	}
+
+	return (spa != NULL);
+}
+
+char *
+spa_strdup(const char *s)
+{
+	size_t len;
+	char *new;
+
+	len = strlen(s);
+	new = kmem_alloc(len + 1, KM_SLEEP);
+	bcopy(s, new, len);
+	new[len] = '\0';
+
+	return (new);
+}
+
+void
+spa_strfree(char *s)
+{
+	kmem_free(s, strlen(s) + 1);
+}
+
+uint64_t
+spa_get_random(uint64_t range)
+{
+	uint64_t r;
+
+	ASSERT(range != 0);
+
+	(void) random_get_pseudo_bytes((void *)&r, sizeof (uint64_t));
+
+	return (r % range);
+}
+
+void
+sprintf_blkptr(char *buf, int len, const blkptr_t *bp)
+{
+	int d;
+
+	if (bp == NULL) {
+		(void) snprintf(buf, len, "<NULL>");
+		return;
+	}
+
+	if (BP_IS_HOLE(bp)) {
+		(void) snprintf(buf, len, "<hole>");
+		return;
+	}
+
+	(void) snprintf(buf, len, "[L%llu %s] %llxL/%llxP ",
+	    (u_longlong_t)BP_GET_LEVEL(bp),
+	    dmu_ot[BP_GET_TYPE(bp)].ot_name,
+	    (u_longlong_t)BP_GET_LSIZE(bp),
+	    (u_longlong_t)BP_GET_PSIZE(bp));
+
+	for (d = 0; d < BP_GET_NDVAS(bp); d++) {
+		const dva_t *dva = &bp->blk_dva[d];
+		(void) snprintf(buf + strlen(buf), len - strlen(buf),
+		    "DVA[%d]=<%llu:%llx:%llx> ", d,
+		    (u_longlong_t)DVA_GET_VDEV(dva),
+		    (u_longlong_t)DVA_GET_OFFSET(dva),
+		    (u_longlong_t)DVA_GET_ASIZE(dva));
+	}
+
+	(void) snprintf(buf + strlen(buf), len - strlen(buf),
+	    "%s %s %s %s birth=%llu fill=%llu cksum=%llx:%llx:%llx:%llx",
+	    zio_checksum_table[BP_GET_CHECKSUM(bp)].ci_name,
+	    zio_compress_table[BP_GET_COMPRESS(bp)].ci_name,
+	    BP_GET_BYTEORDER(bp) == 0 ? "BE" : "LE",
+	    BP_IS_GANG(bp) ? "gang" : "contiguous",
+	    (u_longlong_t)bp->blk_birth,
+	    (u_longlong_t)bp->blk_fill,
+	    (u_longlong_t)bp->blk_cksum.zc_word[0],
+	    (u_longlong_t)bp->blk_cksum.zc_word[1],
+	    (u_longlong_t)bp->blk_cksum.zc_word[2],
+	    (u_longlong_t)bp->blk_cksum.zc_word[3]);
+}
+
+void
+spa_freeze(spa_t *spa)
+{
+	uint64_t freeze_txg = 0;
+
+	spa_config_enter(spa, RW_WRITER, FTAG);
+	if (spa->spa_freeze_txg == UINT64_MAX) {
+		freeze_txg = spa_last_synced_txg(spa) + TXG_SIZE;
+		spa->spa_freeze_txg = freeze_txg;
+	}
+	spa_config_exit(spa, FTAG);
+	if (freeze_txg != 0)
+		txg_wait_synced(spa_get_dsl(spa), freeze_txg);
+}
+
+void
+zfs_panic_recover(const char *fmt, ...)
+{
+	va_list adx;
+
+	va_start(adx, fmt);
+	vcmn_err(zfs_recover ? CE_WARN : CE_PANIC, fmt, adx);
+	va_end(adx);
+}
+
+/*
+ * ==========================================================================
+ * Accessor functions
+ * ==========================================================================
+ */
+
+krwlock_t *
+spa_traverse_rwlock(spa_t *spa)
+{
+	return (&spa->spa_traverse_lock);
+}
+
+int
+spa_traverse_wanted(spa_t *spa)
+{
+	return (spa->spa_traverse_wanted);
+}
+
+dsl_pool_t *
+spa_get_dsl(spa_t *spa)
+{
+	return (spa->spa_dsl_pool);
+}
+
+blkptr_t *
+spa_get_rootblkptr(spa_t *spa)
+{
+	return (&spa->spa_ubsync.ub_rootbp);
+}
+
+void
+spa_set_rootblkptr(spa_t *spa, const blkptr_t *bp)
+{
+	spa->spa_uberblock.ub_rootbp = *bp;
+}
+
+void
+spa_altroot(spa_t *spa, char *buf, size_t buflen)
+{
+	if (spa->spa_root == NULL)
+		buf[0] = '\0';
+	else
+		(void) strncpy(buf, spa->spa_root, buflen);
+}
+
+int
+spa_sync_pass(spa_t *spa)
+{
+	return (spa->spa_sync_pass);
+}
+
+char *
+spa_name(spa_t *spa)
+{
+	/*
+	 * Accessing the name requires holding either the namespace lock or the
+	 * config lock, both of which are required to do a rename.
+	 */
+	ASSERT(MUTEX_HELD(&spa_namespace_lock) ||
+	    spa_config_held(spa, RW_READER) || spa_config_held(spa, RW_WRITER));
+
+	return (spa->spa_name);
+}
+
+uint64_t
+spa_guid(spa_t *spa)
+{
+	/*
+	 * If we fail to parse the config during spa_load(), we can go through
+	 * the error path (which posts an ereport) and end up here with no root
+	 * vdev.  We stash the original pool guid in 'spa_load_guid' to handle
+	 * this case.
+	 */
+	if (spa->spa_root_vdev != NULL)
+		return (spa->spa_root_vdev->vdev_guid);
+	else
+		return (spa->spa_load_guid);
+}
+
+uint64_t
+spa_last_synced_txg(spa_t *spa)
+{
+	return (spa->spa_ubsync.ub_txg);
+}
+
+uint64_t
+spa_first_txg(spa_t *spa)
+{
+	return (spa->spa_first_txg);
+}
+
+int
+spa_state(spa_t *spa)
+{
+	return (spa->spa_state);
+}
+
+uint64_t
+spa_freeze_txg(spa_t *spa)
+{
+	return (spa->spa_freeze_txg);
+}
+
+/*
+ * In the future, this may select among different metaslab classes
+ * depending on the zdp.  For now, there's no such distinction.
+ */
+metaslab_class_t *
+spa_metaslab_class_select(spa_t *spa)
+{
+	return (spa->spa_normal_class);
+}
+
+/*
+ * Return how much space is allocated in the pool (ie. sum of all asize)
+ */
+uint64_t
+spa_get_alloc(spa_t *spa)
+{
+	return (spa->spa_root_vdev->vdev_stat.vs_alloc);
+}
+
+/*
+ * Return how much (raid-z inflated) space there is in the pool.
+ */
+uint64_t
+spa_get_space(spa_t *spa)
+{
+	return (spa->spa_root_vdev->vdev_stat.vs_space);
+}
+
+/*
+ * Return the amount of raid-z-deflated space in the pool.
+ */
+uint64_t
+spa_get_dspace(spa_t *spa)
+{
+	if (spa->spa_deflate)
+		return (spa->spa_root_vdev->vdev_stat.vs_dspace);
+	else
+		return (spa->spa_root_vdev->vdev_stat.vs_space);
+}
+
+/* ARGSUSED */
+uint64_t
+spa_get_asize(spa_t *spa, uint64_t lsize)
+{
+	/*
+	 * For now, the worst case is 512-byte RAID-Z blocks, in which
+	 * case the space requirement is exactly 2x; so just assume that.
+	 * Add to this the fact that we can have up to 3 DVAs per bp, and
+	 * we have to multiply by a total of 6x.
+	 */
+	return (lsize * 6);
+}
+
+uint64_t
+spa_version(spa_t *spa)
+{
+	return (spa->spa_ubsync.ub_version);
+}
+
+int
+spa_max_replication(spa_t *spa)
+{
+	/*
+	 * As of ZFS_VERSION == ZFS_VERSION_DITTO_BLOCKS, we are able to
+	 * handle BPs with more than one DVA allocated.  Set our max
+	 * replication level accordingly.
+	 */
+	if (spa_version(spa) < ZFS_VERSION_DITTO_BLOCKS)
+		return (1);
+	return (MIN(SPA_DVAS_PER_BP, spa_max_replication_override));
+}
+
+uint64_t
+bp_get_dasize(spa_t *spa, const blkptr_t *bp)
+{
+	int sz = 0, i;
+
+	if (!spa->spa_deflate)
+		return (BP_GET_ASIZE(bp));
+
+	for (i = 0; i < SPA_DVAS_PER_BP; i++) {
+		vdev_t *vd =
+		    vdev_lookup_top(spa, DVA_GET_VDEV(&bp->blk_dva[i]));
+		sz += (DVA_GET_ASIZE(&bp->blk_dva[i]) >> SPA_MINBLOCKSHIFT) *
+		    vd->vdev_deflate_ratio;
+	}
+	return (sz);
+}
+
+/*
+ * ==========================================================================
+ * Initialization and Termination
+ * ==========================================================================
+ */
+
+static int
+spa_name_compare(const void *a1, const void *a2)
+{
+	const spa_t *s1 = a1;
+	const spa_t *s2 = a2;
+	int s;
+
+	s = strcmp(s1->spa_name, s2->spa_name);
+	if (s > 0)
+		return (1);
+	if (s < 0)
+		return (-1);
+	return (0);
+}
+
+int
+spa_busy(void)
+{
+	return (spa_active_count);
+}
+
+void
+spa_init(int mode)
+{
+	mutex_init(&spa_namespace_lock, NULL, MUTEX_DEFAULT, NULL);
+	cv_init(&spa_namespace_cv, NULL, CV_DEFAULT, NULL);
+
+	avl_create(&spa_namespace_avl, spa_name_compare, sizeof (spa_t),
+	    offsetof(spa_t, spa_avl));
+
+	mutex_init(&spa_spare_lock, NULL, MUTEX_DEFAULT, NULL);
+
+	avl_create(&spa_spare_avl, spa_spare_compare, sizeof (spa_spare_t),
+	    offsetof(spa_spare_t, spare_avl));
+
+	spa_mode = mode;
+
+	refcount_init();
+	unique_init();
+	zio_init();
+	dmu_init();
+	zil_init();
+	spa_config_load();
+}
+
+void
+spa_fini(void)
+{
+	spa_evict_all();
+
+	zil_fini();
+	dmu_fini();
+	zio_fini();
+	refcount_fini();
+
+	avl_destroy(&spa_namespace_avl);
+	avl_destroy(&spa_spare_avl);
+
+	cv_destroy(&spa_namespace_cv);
+	mutex_destroy(&spa_namespace_lock);
+	mutex_destroy(&spa_spare_lock);
+}