[mirror_zfs.git] / include / sys / vdev_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, 2020 by Delphix. All rights reserved.
 * Copyright (c) 2017, Intel Corporation.
 */

#ifndef _SYS_VDEV_IMPL_H
#define _SYS_VDEV_IMPL_H

#include <sys/avl.h>
#include <sys/bpobj.h>
#include <sys/dmu.h>
#include <sys/metaslab.h>
#include <sys/nvpair.h>
#include <sys/space_map.h>
#include <sys/vdev.h>
#include <sys/dkio.h>
#include <sys/uberblock_impl.h>
#include <sys/vdev_indirect_mapping.h>
#include <sys/vdev_indirect_births.h>
#include <sys/vdev_rebuild.h>
#include <sys/vdev_removal.h>
#include <sys/zfs_ratelimit.h>

#ifdef  __cplusplus
extern "C" {
#endif

/*
 * Virtual device descriptors.
 *
 * All storage pool operations go through the virtual device framework,
 * which provides data replication and I/O scheduling.
 */

/*
 * Forward declarations that lots of things need.
 */
typedef struct vdev_queue vdev_queue_t;
struct abd;

extern uint_t zfs_vdev_queue_depth_pct;
extern uint_t zfs_vdev_def_queue_depth;
extern uint_t zfs_vdev_async_write_max_active;

/*
 * Virtual device operations
 */
typedef int     vdev_init_func_t(spa_t *spa, nvlist_t *nv, void **tsd);
typedef void    vdev_kobj_post_evt_func_t(vdev_t *vd);
typedef void    vdev_fini_func_t(vdev_t *vd);
typedef int     vdev_open_func_t(vdev_t *vd, uint64_t *size, uint64_t *max_size,
    uint64_t *ashift, uint64_t *pshift);
typedef void    vdev_close_func_t(vdev_t *vd);
typedef uint64_t vdev_asize_func_t(vdev_t *vd, uint64_t psize, uint64_t txg);
typedef uint64_t vdev_min_asize_func_t(vdev_t *vd);
typedef uint64_t vdev_min_alloc_func_t(vdev_t *vd);
typedef void    vdev_io_start_func_t(zio_t *zio);
typedef void    vdev_io_done_func_t(zio_t *zio);
typedef void    vdev_state_change_func_t(vdev_t *vd, int, int);
typedef boolean_t vdev_need_resilver_func_t(vdev_t *vd, const dva_t *dva,
    size_t psize, uint64_t phys_birth);
typedef void    vdev_hold_func_t(vdev_t *vd);
typedef void    vdev_rele_func_t(vdev_t *vd);

typedef void    vdev_remap_cb_t(uint64_t inner_offset, vdev_t *vd,
    uint64_t offset, uint64_t size, void *arg);
typedef void    vdev_remap_func_t(vdev_t *vd, uint64_t offset, uint64_t size,
    vdev_remap_cb_t callback, void *arg);
/*
 * Given a target vdev, translates the logical range "in" to the physical
 * range "res"
 */
typedef void vdev_xlation_func_t(vdev_t *cvd, const range_seg64_t *logical,
    range_seg64_t *physical, range_seg64_t *remain);
typedef uint64_t vdev_rebuild_asize_func_t(vdev_t *vd, uint64_t start,
    uint64_t size, uint64_t max_segment);
typedef void vdev_metaslab_init_func_t(vdev_t *vd, uint64_t *startp,
    uint64_t *sizep);
typedef void vdev_config_generate_func_t(vdev_t *vd, nvlist_t *nv);
typedef uint64_t vdev_nparity_func_t(vdev_t *vd);
typedef uint64_t vdev_ndisks_func_t(vdev_t *vd);

typedef const struct vdev_ops {
        vdev_init_func_t                *vdev_op_init;
        vdev_fini_func_t                *vdev_op_fini;
        vdev_open_func_t                *vdev_op_open;
        vdev_close_func_t               *vdev_op_close;
        vdev_asize_func_t               *vdev_op_asize;
        vdev_min_asize_func_t           *vdev_op_min_asize;
        vdev_min_alloc_func_t           *vdev_op_min_alloc;
        vdev_io_start_func_t            *vdev_op_io_start;
        vdev_io_done_func_t             *vdev_op_io_done;
        vdev_state_change_func_t        *vdev_op_state_change;
        vdev_need_resilver_func_t       *vdev_op_need_resilver;
        vdev_hold_func_t                *vdev_op_hold;
        vdev_rele_func_t                *vdev_op_rele;
        vdev_remap_func_t               *vdev_op_remap;
        vdev_xlation_func_t             *vdev_op_xlate;
        vdev_rebuild_asize_func_t       *vdev_op_rebuild_asize;
        vdev_metaslab_init_func_t       *vdev_op_metaslab_init;
        vdev_config_generate_func_t     *vdev_op_config_generate;
        vdev_nparity_func_t             *vdev_op_nparity;
        vdev_ndisks_func_t              *vdev_op_ndisks;
        vdev_kobj_post_evt_func_t       *vdev_op_kobj_evt_post;
        char                            vdev_op_type[16];
        boolean_t                       vdev_op_leaf;
} vdev_ops_t;

/*
 * Virtual device properties
 */
typedef union vdev_queue_class {
        struct {
                ulong_t         vqc_list_numnodes;
                list_t          vqc_list;
        };
        avl_tree_t      vqc_tree;
} vdev_queue_class_t;

struct vdev_queue {
        vdev_t          *vq_vdev;
        vdev_queue_class_t vq_class[ZIO_PRIORITY_NUM_QUEUEABLE];
        avl_tree_t      vq_read_offset_tree;
        avl_tree_t      vq_write_offset_tree;
        uint64_t        vq_last_offset;
        zio_priority_t  vq_last_prio;   /* Last sent I/O priority. */
        uint32_t        vq_cqueued;     /* Classes with queued I/Os. */
        uint32_t        vq_cactive[ZIO_PRIORITY_NUM_QUEUEABLE];
        uint32_t        vq_active;      /* Number of active I/Os. */
        uint32_t        vq_ia_active;   /* Active interactive I/Os. */
        uint32_t        vq_nia_credit;  /* Non-interactive I/Os credit. */
        list_t          vq_active_list; /* List of active I/Os. */
        hrtime_t        vq_io_complete_ts; /* time last i/o completed */
        hrtime_t        vq_io_delta_ts;
        zio_t           vq_io_search; /* used as local for stack reduction */
        kmutex_t        vq_lock;
};

typedef enum vdev_alloc_bias {
        VDEV_BIAS_NONE,
        VDEV_BIAS_LOG,          /* dedicated to ZIL data (SLOG) */
        VDEV_BIAS_SPECIAL,      /* dedicated to ddt, metadata, and small blks */
        VDEV_BIAS_DEDUP         /* dedicated to dedup metadata */
} vdev_alloc_bias_t;


/*
 * On-disk indirect vdev state.
 *
 * An indirect vdev is described exclusively in the MOS config of a pool.
 * The config for an indirect vdev includes several fields, which are
 * accessed in memory by a vdev_indirect_config_t.
 */
typedef struct vdev_indirect_config {
        /*
         * Object (in MOS) which contains the indirect mapping. This object
         * contains an array of vdev_indirect_mapping_entry_phys_t ordered by
         * vimep_src. The bonus buffer for this object is a
         * vdev_indirect_mapping_phys_t. This object is allocated when a vdev
         * removal is initiated.
         *
         * Note that this object can be empty if none of the data on the vdev
         * has been copied yet.
         */
        uint64_t        vic_mapping_object;

        /*
         * Object (in MOS) which contains the birth times for the mapping
         * entries. This object contains an array of
         * vdev_indirect_birth_entry_phys_t sorted by vibe_offset. The bonus
         * buffer for this object is a vdev_indirect_birth_phys_t. This object
         * is allocated when a vdev removal is initiated.
         *
         * Note that this object can be empty if none of the vdev has yet been
         * copied.
         */
        uint64_t        vic_births_object;

        /*
         * This is the vdev ID which was removed previous to this vdev, or
         * UINT64_MAX if there are no previously removed vdevs.
         */
        uint64_t        vic_prev_indirect_vdev;
} vdev_indirect_config_t;

/*
 * Virtual device descriptor
 */
struct vdev {
        /*
         * Common to all vdev types.
         */
        uint64_t        vdev_id;        /* child number in vdev parent  */
        uint64_t        vdev_guid;      /* unique ID for this vdev      */
        uint64_t        vdev_guid_sum;  /* self guid + all child guids  */
        uint64_t        vdev_orig_guid; /* orig. guid prior to remove   */
        uint64_t        vdev_asize;     /* allocatable device capacity  */
        uint64_t        vdev_min_asize; /* min acceptable asize         */
        uint64_t        vdev_max_asize; /* max acceptable asize         */
        uint64_t        vdev_ashift;    /* block alignment shift        */

        /*
         * Logical block alignment shift
         *
         * The smallest sized/aligned I/O supported by the device.
         */
        uint64_t        vdev_logical_ashift;
        /*
         * Physical block alignment shift
         *
         * The device supports logical I/Os with vdev_logical_ashift
         * size/alignment, but optimum performance will be achieved by
         * aligning/sizing requests to vdev_physical_ashift.  Smaller
         * requests may be inflated or incur device level read-modify-write
         * operations.
         *
         * May be 0 to indicate no preference (i.e. use vdev_logical_ashift).
         */
        uint64_t        vdev_physical_ashift;
        uint64_t        vdev_state;     /* see VDEV_STATE_* #defines    */
        uint64_t        vdev_prevstate; /* used when reopening a vdev   */
        vdev_ops_t      *vdev_ops;      /* vdev operations              */
        spa_t           *vdev_spa;      /* spa for this vdev            */
        void            *vdev_tsd;      /* type-specific data           */
        vdev_t          *vdev_top;      /* top-level vdev               */
        vdev_t          *vdev_parent;   /* parent vdev                  */
        vdev_t          **vdev_child;   /* array of children            */
        uint64_t        vdev_children;  /* number of children           */
        vdev_stat_t     vdev_stat;      /* virtual device statistics    */
        vdev_stat_ex_t  vdev_stat_ex;   /* extended statistics          */
        boolean_t       vdev_expanding; /* expand the vdev?             */
        boolean_t       vdev_reopening; /* reopen in progress?          */
        boolean_t       vdev_nonrot;    /* true if solid state          */
        int             vdev_load_error; /* error on last load          */
        int             vdev_open_error; /* error on last open          */
        int             vdev_validate_error; /* error on last validate  */
        kthread_t       *vdev_open_thread; /* thread opening children   */
        kthread_t       *vdev_validate_thread; /* thread validating children */
        uint64_t        vdev_crtxg;     /* txg when top-level was added */
        uint64_t        vdev_root_zap;

        /*
         * Top-level vdev state.
         */
        uint64_t        vdev_ms_array;  /* metaslab array object        */
        uint64_t        vdev_ms_shift;  /* metaslab size shift          */
        uint64_t        vdev_ms_count;  /* number of metaslabs          */
        metaslab_group_t *vdev_mg;      /* metaslab group               */
        metaslab_group_t *vdev_log_mg;  /* embedded slog metaslab group */
        metaslab_t      **vdev_ms;      /* metaslab array               */
        txg_list_t      vdev_ms_list;   /* per-txg dirty metaslab lists */
        txg_list_t      vdev_dtl_list;  /* per-txg dirty DTL lists      */
        txg_node_t      vdev_txg_node;  /* per-txg dirty vdev linkage   */
        boolean_t       vdev_remove_wanted; /* async remove wanted?     */
        boolean_t       vdev_probe_wanted; /* async probe wanted?       */
        list_node_t     vdev_config_dirty_node; /* config dirty list    */
        list_node_t     vdev_state_dirty_node; /* state dirty list      */
        uint64_t        vdev_deflate_ratio; /* deflation ratio (x512)   */
        uint64_t        vdev_islog;     /* is an intent log device      */
        uint64_t        vdev_noalloc;   /* device is passivated?        */
        uint64_t        vdev_removing;  /* device is being removed?     */
        uint64_t        vdev_failfast;  /* device failfast setting      */
        boolean_t       vdev_rz_expanding; /* raidz is being expanded?  */
        boolean_t       vdev_ishole;    /* is a hole in the namespace   */
        uint64_t        vdev_top_zap;
        vdev_alloc_bias_t vdev_alloc_bias; /* metaslab allocation bias  */

        /* pool checkpoint related */
        space_map_t     *vdev_checkpoint_sm;    /* contains reserved blocks */

        /* Initialize related */
        boolean_t       vdev_initialize_exit_wanted;
        vdev_initializing_state_t       vdev_initialize_state;
        list_node_t     vdev_initialize_node;
        kthread_t       *vdev_initialize_thread;
        /* Protects vdev_initialize_thread and vdev_initialize_state. */
        kmutex_t        vdev_initialize_lock;
        kcondvar_t      vdev_initialize_cv;
        uint64_t        vdev_initialize_offset[TXG_SIZE];
        uint64_t        vdev_initialize_last_offset;
        range_tree_t    *vdev_initialize_tree;  /* valid while initializing */
        uint64_t        vdev_initialize_bytes_est;
        uint64_t        vdev_initialize_bytes_done;
        uint64_t        vdev_initialize_action_time;    /* start and end time */

        /* TRIM related */
        boolean_t       vdev_trim_exit_wanted;
        boolean_t       vdev_autotrim_exit_wanted;
        vdev_trim_state_t       vdev_trim_state;
        list_node_t     vdev_trim_node;
        kmutex_t        vdev_autotrim_lock;
        kcondvar_t      vdev_autotrim_cv;
        kcondvar_t      vdev_autotrim_kick_cv;
        kthread_t       *vdev_autotrim_thread;
        /* Protects vdev_trim_thread and vdev_trim_state. */
        kmutex_t        vdev_trim_lock;
        kcondvar_t      vdev_trim_cv;
        kthread_t       *vdev_trim_thread;
        uint64_t        vdev_trim_offset[TXG_SIZE];
        uint64_t        vdev_trim_last_offset;
        uint64_t        vdev_trim_bytes_est;
        uint64_t        vdev_trim_bytes_done;
        uint64_t        vdev_trim_rate;         /* requested rate (bytes/sec) */
        uint64_t        vdev_trim_partial;      /* requested partial TRIM */
        uint64_t        vdev_trim_secure;       /* requested secure TRIM */
        uint64_t        vdev_trim_action_time;  /* start and end time */

        /* Rebuild related */
        boolean_t       vdev_rebuilding;
        boolean_t       vdev_rebuild_exit_wanted;
        boolean_t       vdev_rebuild_cancel_wanted;
        boolean_t       vdev_rebuild_reset_wanted;
        kmutex_t        vdev_rebuild_lock;
        kcondvar_t      vdev_rebuild_cv;
        kthread_t       *vdev_rebuild_thread;
        vdev_rebuild_t  vdev_rebuild_config;

        /* For limiting outstanding I/Os (initialize, TRIM) */
        kmutex_t        vdev_initialize_io_lock;
        kcondvar_t      vdev_initialize_io_cv;
        uint64_t        vdev_initialize_inflight;
        kmutex_t        vdev_trim_io_lock;
        kcondvar_t      vdev_trim_io_cv;
        uint64_t        vdev_trim_inflight[3];

        /*
         * Values stored in the config for an indirect or removing vdev.
         */
        vdev_indirect_config_t  vdev_indirect_config;

        /*
         * The vdev_indirect_rwlock protects the vdev_indirect_mapping
         * pointer from changing on indirect vdevs (when it is condensed).
         * Note that removing (not yet indirect) vdevs have different
         * access patterns (the mapping is not accessed from open context,
         * e.g. from zio_read) and locking strategy (e.g. svr_lock).
         */
        krwlock_t vdev_indirect_rwlock;
        vdev_indirect_mapping_t *vdev_indirect_mapping;
        vdev_indirect_births_t *vdev_indirect_births;

        /*
         * In memory data structures used to manage the obsolete sm, for
         * indirect or removing vdevs.
         *
         * The vdev_obsolete_segments is the in-core record of the segments
         * that are no longer referenced anywhere in the pool (due to
         * being freed or remapped and not referenced by any snapshots).
         * During a sync, segments are added to vdev_obsolete_segments
         * via vdev_indirect_mark_obsolete(); at the end of each sync
         * pass, this is appended to vdev_obsolete_sm via
         * vdev_indirect_sync_obsolete().  The vdev_obsolete_lock
         * protects against concurrent modifications of vdev_obsolete_segments
         * from multiple zio threads.
         */
        kmutex_t        vdev_obsolete_lock;
        range_tree_t    *vdev_obsolete_segments;
        space_map_t     *vdev_obsolete_sm;

        /*
         * Protects the vdev_scan_io_queue field itself as well as the
         * structure's contents (when present).
         */
        kmutex_t                        vdev_scan_io_queue_lock;
        struct dsl_scan_io_queue        *vdev_scan_io_queue;

        /*
         * Leaf vdev state.
         */
        range_tree_t    *vdev_dtl[DTL_TYPES]; /* dirty time logs        */
        space_map_t     *vdev_dtl_sm;   /* dirty time log space map     */
        txg_node_t      vdev_dtl_node;  /* per-txg dirty DTL linkage    */
        uint64_t        vdev_dtl_object; /* DTL object                  */
        uint64_t        vdev_psize;     /* physical device capacity     */
        uint64_t        vdev_wholedisk; /* true if this is a whole disk */
        uint64_t        vdev_offline;   /* persistent offline state     */
        uint64_t        vdev_faulted;   /* persistent faulted state     */
        uint64_t        vdev_degraded;  /* persistent degraded state    */
        uint64_t        vdev_removed;   /* persistent removed state     */
        uint64_t        vdev_resilver_txg; /* persistent resilvering state */
        uint64_t        vdev_rebuild_txg; /* persistent rebuilding state */
        char            *vdev_path;     /* vdev path (if any)           */
        char            *vdev_devid;    /* vdev devid (if any)          */
        char            *vdev_physpath; /* vdev device path (if any)    */
        char            *vdev_enc_sysfs_path;   /* enclosure sysfs path */
        char            *vdev_fru;      /* physical FRU location        */
        uint64_t        vdev_not_present; /* not present during import  */
        uint64_t        vdev_unspare;   /* unspare when resilvering done */
        boolean_t       vdev_nowritecache; /* true if flushwritecache failed */
        boolean_t       vdev_has_trim;  /* TRIM is supported            */
        boolean_t       vdev_has_securetrim; /* secure TRIM is supported */
        boolean_t       vdev_checkremove; /* temporary online test      */
        boolean_t       vdev_forcefault; /* force online fault          */
        boolean_t       vdev_splitting; /* split or repair in progress  */
        boolean_t       vdev_delayed_close; /* delayed device close?    */
        boolean_t       vdev_tmpoffline; /* device taken offline temporarily? */
        boolean_t       vdev_detached;  /* device detached?             */
        boolean_t       vdev_cant_read; /* vdev is failing all reads    */
        boolean_t       vdev_cant_write; /* vdev is failing all writes  */
        boolean_t       vdev_isspare;   /* was a hot spare              */
        boolean_t       vdev_isl2cache; /* was a l2cache device         */
        boolean_t       vdev_copy_uberblocks;  /* post expand copy uberblocks */
        boolean_t       vdev_resilver_deferred;  /* resilver deferred */
        boolean_t       vdev_kobj_flag; /* kobj event record */
        boolean_t       vdev_attaching; /* vdev attach ashift handling */
        vdev_queue_t    vdev_queue;     /* I/O deadline schedule queue  */
        spa_aux_vdev_t  *vdev_aux;      /* for l2cache and spares vdevs */
        zio_t           *vdev_probe_zio; /* root of current probe       */
        vdev_aux_t      vdev_label_aux; /* on-disk aux state            */
        uint64_t        vdev_leaf_zap;
        hrtime_t        vdev_mmp_pending; /* 0 if write finished        */
        uint64_t        vdev_mmp_kstat_id;      /* to find kstat entry */
        uint64_t        vdev_expansion_time;    /* vdev's last expansion time */
        list_node_t     vdev_leaf_node;         /* leaf vdev list */

        /*
         * For DTrace to work in userland (libzpool) context, these fields must
         * remain at the end of the structure.  DTrace will use the kernel's
         * CTF definition for 'struct vdev', and since the size of a kmutex_t is
         * larger in userland, the offsets for the rest of the fields would be
         * incorrect.
         */
        kmutex_t        vdev_dtl_lock;  /* vdev_dtl_{map,resilver}      */
        kmutex_t        vdev_stat_lock; /* vdev_stat                    */
        kmutex_t        vdev_probe_lock; /* protects vdev_probe_zio     */

        /*
         * We rate limit ZIO delay, deadman, and checksum events, since they
         * can flood ZED with tons of events when a drive is acting up.
         */
        zfs_ratelimit_t vdev_delay_rl;
        zfs_ratelimit_t vdev_deadman_rl;
        zfs_ratelimit_t vdev_checksum_rl;

        /*
         * Checksum and IO thresholds for tuning ZED
         */
        uint64_t        vdev_checksum_n;
        uint64_t        vdev_checksum_t;
        uint64_t        vdev_io_n;
        uint64_t        vdev_io_t;
};

#define VDEV_PAD_SIZE           (8 << 10)
/* 2 padding areas (vl_pad1 and vl_be) to skip */
#define VDEV_SKIP_SIZE          VDEV_PAD_SIZE * 2
#define VDEV_PHYS_SIZE          (112 << 10)
#define VDEV_UBERBLOCK_RING     (128 << 10)

/*
 * MMP blocks occupy the last MMP_BLOCKS_PER_LABEL slots in the uberblock
 * ring when MMP is enabled.
 */
#define MMP_BLOCKS_PER_LABEL    1

/* The largest uberblock we support is 8k. */
#define MAX_UBERBLOCK_SHIFT (13)
#define VDEV_UBERBLOCK_SHIFT(vd)        \
        MIN(MAX((vd)->vdev_top->vdev_ashift, UBERBLOCK_SHIFT), \
            MAX_UBERBLOCK_SHIFT)
#define VDEV_UBERBLOCK_COUNT(vd)        \
        (VDEV_UBERBLOCK_RING >> VDEV_UBERBLOCK_SHIFT(vd))
#define VDEV_UBERBLOCK_OFFSET(vd, n)    \
        offsetof(vdev_label_t, vl_uberblock[(n) << VDEV_UBERBLOCK_SHIFT(vd)])
#define VDEV_UBERBLOCK_SIZE(vd)         (1ULL << VDEV_UBERBLOCK_SHIFT(vd))

typedef struct vdev_phys {
        char            vp_nvlist[VDEV_PHYS_SIZE - sizeof (zio_eck_t)];
        zio_eck_t       vp_zbt;
} vdev_phys_t;

typedef enum vbe_vers {
        /*
         * The bootenv file is stored as ascii text in the envblock.
         * It is used by the GRUB bootloader used on Linux to store the
         * contents of the grubenv file. The file is stored as raw ASCII,
         * and is protected by an embedded checksum. By default, GRUB will
         * check if the boot filesystem supports storing the environment data
         * in a special location, and if so, will invoke filesystem specific
         * logic to retrieve it. This can be overridden by a variable, should
         * the user so desire.
         */
        VB_RAW = 0,

        /*
         * The bootenv file is converted to an nvlist and then packed into the
         * envblock.
         */
        VB_NVLIST = 1
} vbe_vers_t;

typedef struct vdev_boot_envblock {
        uint64_t        vbe_version;
        char            vbe_bootenv[VDEV_PAD_SIZE - sizeof (uint64_t) -
                        sizeof (zio_eck_t)];
        zio_eck_t       vbe_zbt;
} vdev_boot_envblock_t;
_Static_assert(sizeof (vdev_boot_envblock_t) == VDEV_PAD_SIZE,
        "vdev_boot_envblock_t wrong size");

typedef struct vdev_label {
        char            vl_pad1[VDEV_PAD_SIZE];                 /*  8K */
        vdev_boot_envblock_t    vl_be;                          /*  8K */
        vdev_phys_t     vl_vdev_phys;                           /* 112K */
        char            vl_uberblock[VDEV_UBERBLOCK_RING];      /* 128K */
} vdev_label_t;                                         /* 256K total */

/*
 * vdev_dirty() flags
 */
#define VDD_METASLAB    0x01
#define VDD_DTL         0x02

/* Offset of embedded boot loader region on each label */
#define VDEV_BOOT_OFFSET        (2 * sizeof (vdev_label_t))
/*
 * Size of embedded boot loader region on each label.
 * The total size of the first two labels plus the boot area is 4MB.
 * On RAIDZ, this space is overwritten during RAIDZ expansion.
 */
#define VDEV_BOOT_SIZE          (7ULL << 19)                    /* 3.5M */

/*
 * Size of label regions at the start and end of each leaf device.
 */
#define VDEV_LABEL_START_SIZE   (2 * sizeof (vdev_label_t) + VDEV_BOOT_SIZE)
#define VDEV_LABEL_END_SIZE     (2 * sizeof (vdev_label_t))
#define VDEV_LABELS             4
#define VDEV_BEST_LABEL         VDEV_LABELS
#define VDEV_OFFSET_IS_LABEL(vd, off)                           \
        (((off) < VDEV_LABEL_START_SIZE) ||                     \
        ((off) >= ((vd)->vdev_psize - VDEV_LABEL_END_SIZE)))

#define VDEV_ALLOC_LOAD         0
#define VDEV_ALLOC_ADD          1
#define VDEV_ALLOC_SPARE        2
#define VDEV_ALLOC_L2CACHE      3
#define VDEV_ALLOC_ROOTPOOL     4
#define VDEV_ALLOC_SPLIT        5
#define VDEV_ALLOC_ATTACH       6

/*
 * Allocate or free a vdev
 */
extern vdev_t *vdev_alloc_common(spa_t *spa, uint_t id, uint64_t guid,
    vdev_ops_t *ops);
extern int vdev_alloc(spa_t *spa, vdev_t **vdp, nvlist_t *config,
    vdev_t *parent, uint_t id, int alloctype);
extern void vdev_free(vdev_t *vd);

/*
 * Add or remove children and parents
 */
extern void vdev_add_child(vdev_t *pvd, vdev_t *cvd);
extern void vdev_remove_child(vdev_t *pvd, vdev_t *cvd);
extern void vdev_compact_children(vdev_t *pvd);
extern vdev_t *vdev_add_parent(vdev_t *cvd, vdev_ops_t *ops);
extern void vdev_remove_parent(vdev_t *cvd);

/*
 * vdev sync load and sync
 */
extern boolean_t vdev_log_state_valid(vdev_t *vd);
extern int vdev_load(vdev_t *vd);
extern int vdev_dtl_load(vdev_t *vd);
extern void vdev_sync(vdev_t *vd, uint64_t txg);
extern void vdev_sync_done(vdev_t *vd, uint64_t txg);
extern void vdev_dirty(vdev_t *vd, int flags, void *arg, uint64_t txg);
extern void vdev_dirty_leaves(vdev_t *vd, int flags, uint64_t txg);

/*
 * Available vdev types.
 */
extern vdev_ops_t vdev_root_ops;
extern vdev_ops_t vdev_mirror_ops;
extern vdev_ops_t vdev_replacing_ops;
extern vdev_ops_t vdev_raidz_ops;
extern vdev_ops_t vdev_draid_ops;
extern vdev_ops_t vdev_draid_spare_ops;
extern vdev_ops_t vdev_disk_ops;
extern vdev_ops_t vdev_file_ops;
extern vdev_ops_t vdev_missing_ops;
extern vdev_ops_t vdev_hole_ops;
extern vdev_ops_t vdev_spare_ops;
extern vdev_ops_t vdev_indirect_ops;

/*
 * Common size functions
 */
extern void vdev_default_xlate(vdev_t *vd, const range_seg64_t *logical_rs,
    range_seg64_t *physical_rs, range_seg64_t *remain_rs);
extern uint64_t vdev_default_asize(vdev_t *vd, uint64_t psize, uint64_t txg);
extern uint64_t vdev_default_min_asize(vdev_t *vd);
extern uint64_t vdev_get_min_asize(vdev_t *vd);
extern void vdev_set_min_asize(vdev_t *vd);
extern uint64_t vdev_get_min_alloc(vdev_t *vd);
extern uint64_t vdev_get_nparity(vdev_t *vd);
extern uint64_t vdev_get_ndisks(vdev_t *vd);

/*
 * Global variables
 */
extern int zfs_vdev_standard_sm_blksz;

/*
 * Functions from vdev_indirect.c
 */
extern void vdev_indirect_sync_obsolete(vdev_t *vd, dmu_tx_t *tx);
extern boolean_t vdev_indirect_should_condense(vdev_t *vd);
extern void spa_condense_indirect_start_sync(vdev_t *vd, dmu_tx_t *tx);
extern int vdev_obsolete_sm_object(vdev_t *vd, uint64_t *sm_obj);
extern int vdev_obsolete_counts_are_precise(vdev_t *vd, boolean_t *are_precise);

/*
 * Other miscellaneous functions
 */
int vdev_checkpoint_sm_object(vdev_t *vd, uint64_t *sm_obj);
void vdev_metaslab_group_create(vdev_t *vd);
uint64_t vdev_best_ashift(uint64_t logical, uint64_t a, uint64_t b);

/*
 * Vdev ashift optimization tunables
 */
extern uint_t zfs_vdev_min_auto_ashift;
extern uint_t zfs_vdev_max_auto_ashift;
int param_set_min_auto_ashift(ZFS_MODULE_PARAM_ARGS);
int param_set_max_auto_ashift(ZFS_MODULE_PARAM_ARGS);

#ifdef  __cplusplus
}
#endif

#endif  /* _SYS_VDEV_IMPL_H */