mirror_zfs/include/sys/spa_impl.h

/*
 * 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 https://opensource.org/licenses/CDDL-1.0.
 * 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 (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2011, 2019 by Delphix. All rights reserved.
 * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
 * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
 * Copyright 2013 Saso Kiselkov. All rights reserved.
 * Copyright (c) 2016 Actifio, Inc. All rights reserved.
 * Copyright (c) 2017, Intel Corporation.
 * Copyright (c) 2019 Datto Inc.
 */

#ifndef _SYS_SPA_IMPL_H
#define	_SYS_SPA_IMPL_H

#include <sys/spa.h>
#include <sys/spa_checkpoint.h>
#include <sys/spa_log_spacemap.h>
#include <sys/vdev.h>
#include <sys/vdev_rebuild.h>
#include <sys/vdev_removal.h>
#include <sys/vdev_raidz.h>
#include <sys/metaslab.h>
#include <sys/dmu.h>
#include <sys/dsl_pool.h>
#include <sys/uberblock_impl.h>
#include <sys/zfs_context.h>
#include <sys/avl.h>
#include <sys/zfs_refcount.h>
#include <sys/bplist.h>
#include <sys/bpobj.h>
#include <sys/dsl_crypt.h>
#include <sys/zfeature.h>
#include <sys/zthr.h>
#include <sys/dsl_deadlist.h>
#include <zfeature_common.h>

#ifdef	__cplusplus
extern "C" {
#endif

typedef struct spa_alloc {
	kmutex_t	spaa_lock;
	avl_tree_t	spaa_tree;
} ____cacheline_aligned spa_alloc_t;

typedef struct spa_error_entry {
	zbookmark_phys_t	se_bookmark;
	char			*se_name;
	avl_node_t		se_avl;
	zbookmark_err_phys_t	se_zep;		/* not accounted in avl_find */
} spa_error_entry_t;

typedef struct spa_history_phys {
	uint64_t sh_pool_create_len;	/* ending offset of zpool create */
	uint64_t sh_phys_max_off;	/* physical EOF */
	uint64_t sh_bof;		/* logical BOF */
	uint64_t sh_eof;		/* logical EOF */
	uint64_t sh_records_lost;	/* num of records overwritten */
} spa_history_phys_t;

/*
 * All members must be uint64_t, for byteswap purposes.
 */
typedef struct spa_removing_phys {
	uint64_t sr_state; /* dsl_scan_state_t */

	/*
	 * The vdev ID that we most recently attempted to remove,
	 * or -1 if no removal has been attempted.
	 */
	uint64_t sr_removing_vdev;

	/*
	 * The vdev ID that we most recently successfully removed,
	 * or -1 if no devices have been removed.
	 */
	uint64_t sr_prev_indirect_vdev;

	uint64_t sr_start_time;
	uint64_t sr_end_time;

	/*
	 * Note that we can not use the space map's or indirect mapping's
	 * accounting as a substitute for these values, because we need to
	 * count frees of not-yet-copied data as though it did the copy.
	 * Otherwise, we could get into a situation where copied > to_copy,
	 * or we complete before copied == to_copy.
	 */
	uint64_t sr_to_copy; /* bytes that need to be copied */
	uint64_t sr_copied; /* bytes that have been copied or freed */
} spa_removing_phys_t;

/*
 * This struct is stored as an entry in the DMU_POOL_DIRECTORY_OBJECT
 * (with key DMU_POOL_CONDENSING_INDIRECT).  It is present if a condense
 * of an indirect vdev's mapping object is in progress.
 */
typedef struct spa_condensing_indirect_phys {
	/*
	 * The vdev ID of the indirect vdev whose indirect mapping is
	 * being condensed.
	 */
	uint64_t	scip_vdev;

	/*
	 * The vdev's old obsolete spacemap.  This spacemap's contents are
	 * being integrated into the new mapping.
	 */
	uint64_t	scip_prev_obsolete_sm_object;

	/*
	 * The new mapping object that is being created.
	 */
	uint64_t	scip_next_mapping_object;
} spa_condensing_indirect_phys_t;

struct spa_aux_vdev {
	uint64_t	sav_object;		/* MOS object for device list */
	nvlist_t	*sav_config;		/* cached device config */
	vdev_t		**sav_vdevs;		/* devices */
	int		sav_count;		/* number devices */
	boolean_t	sav_sync;		/* sync the device list */
	nvlist_t	**sav_pending;		/* pending device additions */
	uint_t		sav_npending;		/* # pending devices */
};

typedef struct spa_config_lock {
	kmutex_t	scl_lock;
	kthread_t	*scl_writer;
	int		scl_write_wanted;
	int		scl_count;
	kcondvar_t	scl_cv;
} ____cacheline_aligned spa_config_lock_t;

typedef struct spa_config_dirent {
	list_node_t	scd_link;
	char		*scd_path;
} spa_config_dirent_t;

typedef enum zio_taskq_type {
	ZIO_TASKQ_ISSUE = 0,
	ZIO_TASKQ_ISSUE_HIGH,
	ZIO_TASKQ_INTERRUPT,
	ZIO_TASKQ_INTERRUPT_HIGH,
	ZIO_TASKQ_TYPES
} zio_taskq_type_t;

/*
 * State machine for the zpool-poolname process.  The states transitions
 * are done as follows:
 *
 *	From		   To			Routine
 *	PROC_NONE	-> PROC_CREATED		spa_activate()
 *	PROC_CREATED	-> PROC_ACTIVE		spa_thread()
 *	PROC_ACTIVE	-> PROC_DEACTIVATE	spa_deactivate()
 *	PROC_DEACTIVATE	-> PROC_GONE		spa_thread()
 *	PROC_GONE	-> PROC_NONE		spa_deactivate()
 */
typedef enum spa_proc_state {
	SPA_PROC_NONE,		/* spa_proc = &p0, no process created */
	SPA_PROC_CREATED,	/* spa_activate() has proc, is waiting */
	SPA_PROC_ACTIVE,	/* taskqs created, spa_proc set */
	SPA_PROC_DEACTIVATE,	/* spa_deactivate() requests process exit */
	SPA_PROC_GONE		/* spa_thread() is exiting, spa_proc = &p0 */
} spa_proc_state_t;

typedef struct spa_taskqs {
	uint_t stqs_count;
	taskq_t **stqs_taskq;
} spa_taskqs_t;

/* one for each thread in the spa sync taskq */
typedef struct spa_syncthread_info {
	kthread_t	*sti_thread;
	taskq_t		*sti_wr_iss_tq;		/* assigned wr_iss taskq */
} spa_syncthread_info_t;

typedef enum spa_all_vdev_zap_action {
	AVZ_ACTION_NONE = 0,
	AVZ_ACTION_DESTROY,	/* Destroy all per-vdev ZAPs and the AVZ. */
	AVZ_ACTION_REBUILD,	/* Populate the new AVZ, see spa_avz_rebuild */
	AVZ_ACTION_INITIALIZE
} spa_avz_action_t;

typedef enum spa_config_source {
	SPA_CONFIG_SRC_NONE = 0,
	SPA_CONFIG_SRC_SCAN,		/* scan of path (default: /dev/dsk) */
	SPA_CONFIG_SRC_CACHEFILE,	/* any cachefile */
	SPA_CONFIG_SRC_TRYIMPORT,	/* returned from call to tryimport */
	SPA_CONFIG_SRC_SPLIT,		/* new pool in a pool split */
	SPA_CONFIG_SRC_MOS		/* MOS, but not always from right txg */
} spa_config_source_t;

struct spa {
	/*
	 * Fields protected by spa_namespace_lock.
	 */
	char		spa_name[ZFS_MAX_DATASET_NAME_LEN];	/* pool name */
	char		*spa_comment;		/* comment */
	avl_node_t	spa_avl;		/* node in spa_namespace_avl */
	nvlist_t	*spa_config;		/* last synced config */
	nvlist_t	*spa_config_syncing;	/* currently syncing config */
	nvlist_t	*spa_config_splitting;	/* config for splitting */
	nvlist_t	*spa_load_info;		/* info and errors from load */
	uint64_t	spa_config_txg;		/* txg of last config change */
	uint32_t	spa_sync_pass;		/* iterate-to-convergence */
	pool_state_t	spa_state;		/* pool state */
	int		spa_inject_ref;		/* injection references */
	uint8_t		spa_sync_on;		/* sync threads are running */
	spa_load_state_t spa_load_state;	/* current load operation */
	boolean_t	spa_indirect_vdevs_loaded; /* mappings loaded? */
	boolean_t	spa_trust_config;	/* do we trust vdev tree? */
	boolean_t	spa_is_splitting;	/* in the middle of a split? */
	spa_config_source_t spa_config_source;	/* where config comes from? */
	uint64_t	spa_import_flags;	/* import specific flags */
	spa_taskqs_t	spa_zio_taskq[ZIO_TYPES][ZIO_TASKQ_TYPES];
	dsl_pool_t	*spa_dsl_pool;
	boolean_t	spa_is_initializing;	/* true while opening pool */
	boolean_t	spa_is_exporting;	/* true while exporting pool */
	metaslab_class_t *spa_normal_class;	/* normal data class */
	metaslab_class_t *spa_log_class;	/* intent log data class */
	metaslab_class_t *spa_embedded_log_class; /* log on normal vdevs */
	metaslab_class_t *spa_special_class;	/* special allocation class */
	metaslab_class_t *spa_dedup_class;	/* dedup allocation class */
	uint64_t	spa_first_txg;		/* first txg after spa_open() */
	uint64_t	spa_final_txg;		/* txg of export/destroy */
	uint64_t	spa_freeze_txg;		/* freeze pool at this txg */
	uint64_t	spa_load_max_txg;	/* best initial ub_txg */
	uint64_t	spa_claim_max_txg;	/* highest claimed birth txg */
	inode_timespec_t spa_loaded_ts;		/* 1st successful open time */
	objset_t	*spa_meta_objset;	/* copy of dp->dp_meta_objset */
	kmutex_t	spa_evicting_os_lock;	/* Evicting objset list lock */
	list_t		spa_evicting_os_list;	/* Objsets being evicted. */
	kcondvar_t	spa_evicting_os_cv;	/* Objset Eviction Completion */
	txg_list_t	spa_vdev_txg_list;	/* per-txg dirty vdev list */
	vdev_t		*spa_root_vdev;		/* top-level vdev container */
	uint64_t	spa_min_ashift;		/* of vdevs in normal class */
	uint64_t	spa_max_ashift;		/* of vdevs in normal class */
	uint64_t	spa_min_alloc;		/* of vdevs in normal class */
	uint64_t	spa_gcd_alloc;		/* of vdevs in normal class */
	uint64_t	spa_config_guid;	/* config pool guid */
	uint64_t	spa_load_guid;		/* spa_load initialized guid */
	uint64_t	spa_last_synced_guid;	/* last synced guid */
	list_t		spa_config_dirty_list;	/* vdevs with dirty config */
	list_t		spa_state_dirty_list;	/* vdevs with dirty state */
	/*
	 * spa_allocs is an array, whose lengths is stored in spa_alloc_count.
	 * There is one tree and one lock for each allocator, to help improve
	 * allocation performance in write-heavy workloads.
	 */
	spa_alloc_t	*spa_allocs;
	int		spa_alloc_count;
	int		spa_active_allocator;	/* selectable allocator */

	/* per-allocator sync thread taskqs */
	taskq_t		*spa_sync_tq;
	spa_syncthread_info_t *spa_syncthreads;

	spa_aux_vdev_t	spa_spares;		/* hot spares */
	spa_aux_vdev_t	spa_l2cache;		/* L2ARC cache devices */
	nvlist_t	*spa_label_features;	/* Features for reading MOS */
	uint64_t	spa_config_object;	/* MOS object for pool config */
	uint64_t	spa_config_generation;	/* config generation number */
	uint64_t	spa_syncing_txg;	/* txg currently syncing */
	bpobj_t		spa_deferred_bpobj;	/* deferred-free bplist */
	bplist_t	spa_free_bplist[TXG_SIZE]; /* bplist of stuff to free */
	zio_cksum_salt_t spa_cksum_salt;	/* secret salt for cksum */
	/* checksum context templates */
	kmutex_t	spa_cksum_tmpls_lock;
	void		*spa_cksum_tmpls[ZIO_CHECKSUM_FUNCTIONS];
	uberblock_t	spa_ubsync;		/* last synced uberblock */
	uberblock_t	spa_uberblock;		/* current uberblock */
	boolean_t	spa_extreme_rewind;	/* rewind past deferred frees */
	kmutex_t	spa_scrub_lock;		/* resilver/scrub lock */
	uint64_t	spa_scrub_inflight;	/* in-flight scrub bytes */

	/* in-flight verification bytes */
	uint64_t	spa_load_verify_bytes;
	kcondvar_t	spa_scrub_io_cv;	/* scrub I/O completion */
	uint8_t		spa_scrub_active;	/* active or suspended? */
	uint8_t		spa_scrub_type;		/* type of scrub we're doing */
	uint8_t		spa_scrub_finished;	/* indicator to rotate logs */
	uint8_t		spa_scrub_started;	/* started since last boot */
	uint8_t		spa_scrub_reopen;	/* scrub doing vdev_reopen */
	uint64_t	spa_scan_pass_start;	/* start time per pass/reboot */
	uint64_t	spa_scan_pass_scrub_pause; /* scrub pause time */
	uint64_t	spa_scan_pass_scrub_spent_paused; /* total paused */
	uint64_t	spa_scan_pass_exam;	/* examined bytes per pass */
	uint64_t	spa_scan_pass_issued;	/* issued bytes per pass */

	/* error scrub pause time in milliseconds */
	uint64_t	spa_scan_pass_errorscrub_pause;
	/* total error scrub paused time in milliseconds */
	uint64_t	spa_scan_pass_errorscrub_spent_paused;
	/*
	 * We are in the middle of a resilver, and another resilver
	 * is needed once this one completes. This is set iff any
	 * vdev_resilver_deferred is set.
	 */
	boolean_t	spa_resilver_deferred;
	kmutex_t	spa_async_lock;		/* protect async state */
	kthread_t	*spa_async_thread;	/* thread doing async task */
	int		spa_async_suspended;	/* async tasks suspended */
	kcondvar_t	spa_async_cv;		/* wait for thread_exit() */
	uint16_t	spa_async_tasks;	/* async task mask */
	uint64_t	spa_missing_tvds;	/* unopenable tvds on load */
	uint64_t	spa_missing_tvds_allowed; /* allow loading spa? */

	uint64_t	spa_nonallocating_dspace;
	spa_removing_phys_t spa_removing_phys;
	spa_vdev_removal_t *spa_vdev_removal;

	spa_condensing_indirect_phys_t	spa_condensing_indirect_phys;
	spa_condensing_indirect_t	*spa_condensing_indirect;
	zthr_t		*spa_condense_zthr;	/* zthr doing condense. */

	vdev_raidz_expand_t	*spa_raidz_expand;
	zthr_t		*spa_raidz_expand_zthr;

	uint64_t	spa_checkpoint_txg;	/* the txg of the checkpoint */
	spa_checkpoint_info_t spa_checkpoint_info; /* checkpoint accounting */
	zthr_t		*spa_checkpoint_discard_zthr;

	space_map_t	*spa_syncing_log_sm;	/* current log space map */
	avl_tree_t	spa_sm_logs_by_txg;
	kmutex_t	spa_flushed_ms_lock;	/* for metaslabs_by_flushed */
	avl_tree_t	spa_metaslabs_by_flushed;
	spa_unflushed_stats_t	spa_unflushed_stats;
	list_t		spa_log_summary;
	uint64_t	spa_log_flushall_txg;

	zthr_t		*spa_livelist_delete_zthr; /* deleting livelists */
	zthr_t		*spa_livelist_condense_zthr; /* condensing livelists */
	uint64_t	spa_livelists_to_delete; /* set of livelists to free */
	livelist_condense_entry_t	spa_to_condense; /* next to condense */

	char		*spa_root;		/* alternate root directory */
	uint64_t	spa_ena;		/* spa-wide ereport ENA */
	int		spa_last_open_failed;	/* error if last open failed */
	uint64_t	spa_last_ubsync_txg;	/* "best" uberblock txg */
	uint64_t	spa_last_ubsync_txg_ts;	/* timestamp from that ub */
	uint64_t	spa_load_txg;		/* ub txg that loaded */
	uint64_t	spa_load_txg_ts;	/* timestamp from that ub */
	uint64_t	spa_load_meta_errors;	/* verify metadata err count */
	uint64_t	spa_load_data_errors;	/* verify data err count */
	uint64_t	spa_verify_min_txg;	/* start txg of verify scrub */
	kmutex_t	spa_errlog_lock;	/* error log lock */
	uint64_t	spa_errlog_last;	/* last error log object */
	uint64_t	spa_errlog_scrub;	/* scrub error log object */
	kmutex_t	spa_errlist_lock;	/* error list/ereport lock */
	avl_tree_t	spa_errlist_last;	/* last error list */
	avl_tree_t	spa_errlist_scrub;	/* scrub error list */
	avl_tree_t	spa_errlist_healed;	/* list of healed blocks */
	uint64_t	spa_deflate;		/* should we deflate? */
	uint64_t	spa_history;		/* history object */
	kmutex_t	spa_history_lock;	/* history lock */
	vdev_t		*spa_pending_vdev;	/* pending vdev additions */
	kmutex_t	spa_props_lock;		/* property lock */
	uint64_t	spa_pool_props_object;	/* object for properties */
	uint64_t	spa_bootfs;		/* default boot filesystem */
	uint64_t	spa_failmode;		/* failure mode for the pool */
	uint64_t	spa_deadman_failmode;	/* failure mode for deadman */
	uint64_t	spa_delegation;		/* delegation on/off */
	list_t		spa_config_list;	/* previous cache file(s) */
	/* per-CPU array of root of async I/O: */
	zio_t		**spa_async_zio_root;
	zio_t		*spa_suspend_zio_root;	/* root of all suspended I/O */
	zio_t		*spa_txg_zio[TXG_SIZE]; /* spa_sync() waits for this */
	kmutex_t	spa_suspend_lock;	/* protects suspend_zio_root */
	kcondvar_t	spa_suspend_cv;		/* notification of resume */
	zio_suspend_reason_t	spa_suspended;	/* pool is suspended */
	uint8_t		spa_claiming;		/* pool is doing zil_claim() */
	boolean_t	spa_is_root;		/* pool is root */
	int		spa_minref;		/* num refs when first opened */
	spa_mode_t	spa_mode;		/* SPA_MODE_{READ|WRITE} */
	boolean_t	spa_read_spacemaps;	/* spacemaps available if ro */
	spa_log_state_t spa_log_state;		/* log state */
	uint64_t	spa_autoexpand;		/* lun expansion on/off */
	ddt_t		*spa_ddt[ZIO_CHECKSUM_FUNCTIONS]; /* in-core DDTs */
	uint64_t	spa_ddt_stat_object;	/* DDT statistics */
	uint64_t	spa_dedup_dspace;	/* Cache get_dedup_dspace() */
	uint64_t	spa_dedup_checksum;	/* default dedup checksum */
	uint64_t	spa_dspace;		/* dspace in normal class */
	struct brt	*spa_brt;		/* in-core BRT */
	kmutex_t	spa_vdev_top_lock;	/* dueling offline/remove */
	kmutex_t	spa_proc_lock;		/* protects spa_proc* */
	kcondvar_t	spa_proc_cv;		/* spa_proc_state transitions */
	spa_proc_state_t spa_proc_state;	/* see definition */
	proc_t		*spa_proc;		/* "zpool-poolname" process */
	uintptr_t	spa_did;		/* if procp != p0, did of t1 */
	boolean_t	spa_autoreplace;	/* autoreplace set in open */
	int		spa_vdev_locks;		/* locks grabbed */
	uint64_t	spa_creation_version;	/* version at pool creation */
	uint64_t	spa_prev_software_version; /* See ub_software_version */
	uint64_t	spa_feat_for_write_obj;	/* required to write to pool */
	uint64_t	spa_feat_for_read_obj;	/* required to read from pool */
	uint64_t	spa_feat_desc_obj;	/* Feature descriptions */
	uint64_t	spa_feat_enabled_txg_obj; /* Feature enabled txg */
	kmutex_t	spa_feat_stats_lock;	/* protects spa_feat_stats */
	nvlist_t	*spa_feat_stats;	/* Cache of enabled features */
	/* cache feature refcounts */
	uint64_t	spa_feat_refcount_cache[SPA_FEATURES];
	taskqid_t	spa_deadman_tqid;	/* Task id */
	uint64_t	spa_deadman_calls;	/* number of deadman calls */
	hrtime_t	spa_sync_starttime;	/* starting time of spa_sync */
	uint64_t	spa_deadman_synctime;	/* deadman sync expiration */
	uint64_t	spa_deadman_ziotime;	/* deadman zio expiration */
	uint64_t	spa_all_vdev_zaps;	/* ZAP of per-vd ZAP obj #s */
	spa_avz_action_t	spa_avz_action;	/* destroy/rebuild AVZ? */
	uint64_t	spa_autotrim;		/* automatic background trim? */
	uint64_t	spa_errata;		/* errata issues detected */
	spa_stats_t	spa_stats;		/* assorted spa statistics */
	spa_keystore_t	spa_keystore;		/* loaded crypto keys */

	/* arc_memory_throttle() parameters during low memory condition */
	uint64_t	spa_lowmem_page_load;	/* memory load during txg */
	uint64_t	spa_lowmem_last_txg;	/* txg window start */

	hrtime_t	spa_ccw_fail_time;	/* Conf cache write fail time */
	taskq_t		*spa_zvol_taskq;	/* Taskq for minor management */
	taskq_t		*spa_metaslab_taskq;	/* Taskq for metaslab preload */
	taskq_t		*spa_prefetch_taskq;	/* Taskq for prefetch threads */
	taskq_t		*spa_upgrade_taskq;	/* Taskq for upgrade jobs */
	uint64_t	spa_multihost;		/* multihost aware (mmp) */
	mmp_thread_t	spa_mmp;		/* multihost mmp thread */
	list_t		spa_leaf_list;		/* list of leaf vdevs */
	uint64_t	spa_leaf_list_gen;	/* track leaf_list changes */
	uint32_t	spa_hostid;		/* cached system hostid */

	/* synchronization for threads in spa_wait */
	kmutex_t	spa_activities_lock;
	kcondvar_t	spa_activities_cv;
	kcondvar_t	spa_waiters_cv;
	int		spa_waiters;		/* number of waiting threads */
	boolean_t	spa_waiters_cancel;	/* waiters should return */

	char		*spa_compatibility;	/* compatibility file(s) */

	/*
	 * spa_refcount & spa_config_lock must be the last elements
	 * because zfs_refcount_t changes size based on compilation options.
	 * In order for the MDB module to function correctly, the other
	 * fields must remain in the same location.
	 */
	spa_config_lock_t spa_config_lock[SCL_LOCKS]; /* config changes */
	zfs_refcount_t	spa_refcount;		/* number of opens */
};

extern char *spa_config_path;
extern const char *zfs_deadman_failmode;
extern uint_t spa_slop_shift;
extern void spa_taskq_dispatch_ent(spa_t *spa, zio_type_t t, zio_taskq_type_t q,
    task_func_t *func, void *arg, uint_t flags, taskq_ent_t *ent, zio_t *zio);
extern void spa_taskq_dispatch_sync(spa_t *, zio_type_t t, zio_taskq_type_t q,
    task_func_t *func, void *arg, uint_t flags);
extern void spa_load_spares(spa_t *spa);
extern void spa_load_l2cache(spa_t *spa);
extern sysevent_t *spa_event_create(spa_t *spa, vdev_t *vd, nvlist_t *hist_nvl,
    const char *name);
extern void spa_event_post(sysevent_t *ev);
extern int param_set_deadman_failmode_common(const char *val);
extern void spa_set_deadman_synctime(hrtime_t ns);
extern void spa_set_deadman_ziotime(hrtime_t ns);
extern const char *spa_history_zone(void);
extern const char *zfs_active_allocator;
extern int param_set_active_allocator_common(const char *val);

#ifdef	__cplusplus
}
#endif

#endif	/* _SYS_SPA_IMPL_H */