HAMMER 60C/many: Mirroring

[dragonfly.git] / sys / vfs / hammer / hammer.h

/*
 * Copyright (c) 2007-2008 The DragonFly Project.  All rights reserved.
 * 
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com>
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name of The DragonFly Project nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific, prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * 
 * $DragonFly: src/sys/vfs/hammer/hammer.h,v 1.102 2008/07/04 07:25:36 dillon Exp $
 */
/*
 * This header file contains structures used internally by the HAMMERFS
 * implementation.  See hammer_disk.h for on-disk structures.
 */

#include <sys/param.h>
#include <sys/types.h>
#include <sys/kernel.h>
#include <sys/conf.h>
#include <sys/systm.h>
#include <sys/tree.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/mountctl.h>
#include <sys/vnode.h>
#include <sys/proc.h>
#include <sys/stat.h>
#include <sys/globaldata.h>
#include <sys/lockf.h>
#include <sys/buf.h>
#include <sys/queue.h>
#include <sys/ktr.h>
#include <sys/globaldata.h>

#include <sys/buf2.h>
#include <sys/signal2.h>
#include "hammer_disk.h"
#include "hammer_mount.h"
#include "hammer_ioctl.h"

#if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)

MALLOC_DECLARE(M_HAMMER);

/*
 * Kernel trace
 */
#if !defined(KTR_HAMMER)
#define KTR_HAMMER      KTR_ALL
#endif
KTR_INFO_MASTER_EXTERN(hammer);

/*
 * Misc structures
 */
struct hammer_mount;

/*
 * Key structure used for custom RB tree inode lookups.  This prototypes
 * the function hammer_ino_rb_tree_RB_LOOKUP_INFO(root, info).
 */
typedef struct hammer_inode_info {
        int64_t         obj_id;         /* (key) object identifier */
        hammer_tid_t    obj_asof;       /* (key) snapshot transid or 0 */
        u_int32_t       obj_localization; /* (key) pseudo-fs */
        union {
                struct hammer_btree_leaf_elm *leaf;
        } u;
} *hammer_inode_info_t;

typedef enum hammer_transaction_type {
        HAMMER_TRANS_RO,
        HAMMER_TRANS_STD,
        HAMMER_TRANS_FLS
} hammer_transaction_type_t;

/*
 * HAMMER Transaction tracking
 */
struct hammer_transaction {
        hammer_transaction_type_t type;
        struct hammer_mount *hmp;
        hammer_tid_t    tid;
        u_int64_t       time;
        u_int32_t       time32;
        int             sync_lock_refs;
        struct hammer_volume *rootvol;
};

typedef struct hammer_transaction *hammer_transaction_t;

/*
 * HAMMER locks
 */
struct hammer_lock {
        int     refs;           /* active references delay writes */
        int     lockcount;      /* lock count for exclusive/shared access */
        int     wanted;
        int     exwanted;       /* number of threads waiting for ex lock */
        struct thread *locktd;
};

static __inline int
hammer_islocked(struct hammer_lock *lock)
{
        return(lock->lockcount != 0);
}

static __inline int
hammer_isactive(struct hammer_lock *lock)
{
        return(lock->refs != 0);
}

static __inline int
hammer_islastref(struct hammer_lock *lock)
{
        return(lock->refs == 1);
}

/*
 * Return if we specifically own the lock exclusively.
 */
static __inline int
hammer_lock_excl_owned(struct hammer_lock *lock, thread_t td)
{
        if (lock->lockcount > 0 && lock->locktd == td)
                return(1);
        return(0);
}

/*
 * Flush state, used by various structures
 */
typedef enum hammer_inode_state {
        HAMMER_FST_IDLE,
        HAMMER_FST_SETUP,
        HAMMER_FST_FLUSH
} hammer_inode_state_t;

TAILQ_HEAD(hammer_record_list, hammer_record);

/*
 * Pseudo-filesystem extended data tracking
 */
struct hammer_pfs_rb_tree;
struct hammer_pseudofs_inmem;
RB_HEAD(hammer_pfs_rb_tree, hammer_pseudofs_inmem);
RB_PROTOTYPE2(hammer_pfs_rb_tree, hammer_pseudofs_inmem, rb_node,
              hammer_pfs_rb_compare, u_int32_t);

struct hammer_pseudofs_inmem {
        RB_ENTRY(hammer_pseudofs_inmem) rb_node;
        struct hammer_lock      lock;
        u_int32_t               localization;
        struct hammer_pseudofs_data pfsd;
};

typedef struct hammer_pseudofs_inmem *hammer_pseudofs_inmem_t;

/*
 * Cache object ids.  A fixed number of objid cache structures are
 * created to reserve object id's for newly created files in multiples
 * of 100,000, localized to a particular directory, and recycled as
 * needed.  This allows parallel create operations in different
 * directories to retain fairly localized object ids which in turn
 * improves reblocking performance and layout.
 */
#define OBJID_CACHE_SIZE        1024
#define OBJID_CACHE_BULK        100000

typedef struct hammer_objid_cache {
        TAILQ_ENTRY(hammer_objid_cache) entry;
        struct hammer_inode             *dip;
        hammer_tid_t                    next_tid;
        int                             count;
} *hammer_objid_cache_t;

/*
 * Associate an inode with a B-Tree node to cache search start positions
 */
typedef struct hammer_node_cache {
        TAILQ_ENTRY(hammer_node_cache) entry;
        struct hammer_node              *node;
        struct hammer_inode             *ip;
} *hammer_node_cache_t;

TAILQ_HEAD(hammer_node_cache_list, hammer_node_cache);

/*
 * Structure used to represent an inode in-memory.
 *
 * The record and data associated with an inode may be out of sync with
 * the disk (xDIRTY flags), or not even on the disk at all (ONDISK flag
 * clear).
 *
 * An inode may also hold a cache of unsynchronized records, used for
 * database and directories only.  Unsynchronized regular file data is
 * stored in the buffer cache.
 *
 * NOTE: A file which is created and destroyed within the initial
 * synchronization period can wind up not doing any disk I/O at all.
 *
 * Finally, an inode may cache numerous disk-referencing B-Tree cursors.
 */
struct hammer_ino_rb_tree;
struct hammer_inode;
RB_HEAD(hammer_ino_rb_tree, hammer_inode);
RB_PROTOTYPEX(hammer_ino_rb_tree, INFO, hammer_inode, rb_node,
              hammer_ino_rb_compare, hammer_inode_info_t);

struct hammer_rec_rb_tree;
struct hammer_record;
RB_HEAD(hammer_rec_rb_tree, hammer_record);
RB_PROTOTYPEX(hammer_rec_rb_tree, INFO, hammer_record, rb_node,
              hammer_rec_rb_compare, hammer_btree_leaf_elm_t);

TAILQ_HEAD(hammer_node_list, hammer_node);

struct hammer_inode {
        RB_ENTRY(hammer_inode)  rb_node;
        hammer_inode_state_t    flush_state;
        int                     flush_group;
        TAILQ_ENTRY(hammer_inode) flush_entry;
        struct hammer_record_list target_list;  /* target of dependant recs */
        u_int64_t               obj_id;         /* (key) object identifier */
        hammer_tid_t            obj_asof;       /* (key) snapshot or 0 */
        u_int32_t               obj_localization; /* (key) pseudo-fs */
        struct hammer_mount     *hmp;
        hammer_objid_cache_t    objid_cache;
        int                     flags;
        int                     error;          /* flush error */
        int                     cursor_ip_refs; /* sanity */
        int                     rsv_recs;
        struct vnode            *vp;
        hammer_pseudofs_inmem_t pfsm;
        struct lockf            advlock;
        struct hammer_lock      lock;           /* sync copy interlock */
        off_t                   trunc_off;
        struct hammer_btree_leaf_elm ino_leaf;  /* in-memory cache */
        struct hammer_inode_data ino_data;      /* in-memory cache */
        struct hammer_rec_rb_tree rec_tree;     /* in-memory cache */
        struct hammer_node_cache cache[2];      /* search initiate cache */

        /*
         * When a demark is created to synchronize an inode to
         * disk, certain fields are copied so the front-end VOPs
         * can continue to run in parallel with the synchronization
         * occuring in the background.
         */
        int             sync_flags;             /* to-sync flags cache */
        off_t           sync_trunc_off;         /* to-sync truncation */
        off_t           save_trunc_off;         /* write optimization */
        struct hammer_btree_leaf_elm sync_ino_leaf; /* to-sync cache */
        struct hammer_inode_data sync_ino_data; /* to-sync cache */
};

typedef struct hammer_inode *hammer_inode_t;

#define VTOI(vp)        ((struct hammer_inode *)(vp)->v_data)

#define HAMMER_INODE_DDIRTY     0x0001  /* in-memory ino_data is dirty */
                                        /* (not including atime/mtime) */
#define HAMMER_INODE_RSV_INODES 0x0002  /* hmp->rsv_inodes bumped */
#define HAMMER_INODE_PFSD       0x0004  /* obj_asof set based on pfsd */
#define HAMMER_INODE_XDIRTY     0x0008  /* in-memory records */
#define HAMMER_INODE_ONDISK     0x0010  /* inode is on-disk (else not yet) */
#define HAMMER_INODE_FLUSH      0x0020  /* flush on last ref */
#define HAMMER_INODE_DELETED    0x0080  /* inode delete (backend) */
#define HAMMER_INODE_DELONDISK  0x0100  /* delete synchronized to disk */
#define HAMMER_INODE_RO         0x0200  /* read-only (because of as-of) */
#define HAMMER_INODE_VHELD      0x0400  /* vnode held on sync */
#define HAMMER_INODE_DONDISK    0x0800  /* data records may be on disk */
#define HAMMER_INODE_BUFS       0x1000  /* dirty high level bps present */
#define HAMMER_INODE_REFLUSH    0x2000  /* pipelined flush during flush */
#define HAMMER_INODE_RECLAIM    0x4000  /* trying to reclaim */
#define HAMMER_INODE_FLUSHW     0x8000  /* Someone waiting for flush */

#define HAMMER_INODE_TRUNCATED  0x00010000
#define HAMMER_INODE_DELETING   0x00020000 /* inode delete request (frontend)*/
#define HAMMER_INODE_RESIGNAL   0x00040000 /* re-signal on re-flush */
#define HAMMER_INODE_ATIME      0x00100000 /* in-memory atime modified */
#define HAMMER_INODE_MTIME      0x00200000 /* in-memory mtime modified */
#define HAMMER_INODE_WOULDBLOCK 0x00400000 /* re-issue to new flush group */

#define HAMMER_INODE_MODMASK    (HAMMER_INODE_DDIRTY|                       \
                                 HAMMER_INODE_XDIRTY|HAMMER_INODE_BUFS|     \
                                 HAMMER_INODE_ATIME|HAMMER_INODE_MTIME|     \
                                 HAMMER_INODE_TRUNCATED|HAMMER_INODE_DELETING)

#define HAMMER_INODE_MODMASK_NOXDIRTY \
                                (HAMMER_INODE_MODMASK & ~HAMMER_INODE_XDIRTY)

#define HAMMER_FLUSH_GROUP_SIZE 64

#define HAMMER_FLUSH_SIGNAL     0x0001
#define HAMMER_FLUSH_RECURSION  0x0002

/*
 * Used by the inode reclaim code to pipeline reclaims and avoid
 * blowing out kernel memory or letting the flusher get too far
 * behind.
 */
struct hammer_reclaim {
        TAILQ_ENTRY(hammer_reclaim) entry;
        int     okydoky;
};

#define HAMMER_RECLAIM_FLUSH    2000
#define HAMMER_RECLAIM_WAIT     4000

/*
 * Structure used to represent an unsynchronized record in-memory.  These
 * records typically represent directory entries.  Only non-historical
 * records are kept in-memory.
 *
 * Records are organized as a per-inode RB-Tree.  If the inode is not
 * on disk then neither are any records and the in-memory record tree
 * represents the entire contents of the inode.  If the inode is on disk
 * then the on-disk B-Tree is scanned in parallel with the in-memory
 * RB-Tree to synthesize the current state of the file.
 *
 * Records are also used to enforce the ordering of directory create/delete
 * operations.  A new inode will not be flushed to disk unless its related
 * directory entry is also being flushed at the same time.  A directory entry
 * will not be removed unless its related inode is also being removed at the
 * same time.
 */
typedef enum hammer_record_type {
        HAMMER_MEM_RECORD_GENERAL,      /* misc record */
        HAMMER_MEM_RECORD_INODE,        /* inode record */
        HAMMER_MEM_RECORD_ADD,          /* positive memory cache record */
        HAMMER_MEM_RECORD_DEL,          /* negative delete-on-disk record */
        HAMMER_MEM_RECORD_DATA          /* bulk-data record w/on-disk ref */
} hammer_record_type_t;

struct hammer_record {
        RB_ENTRY(hammer_record)         rb_node;
        TAILQ_ENTRY(hammer_record)      target_entry;
        hammer_inode_state_t            flush_state;
        int                             flush_group;
        hammer_record_type_t            type;
        struct hammer_lock              lock;
        struct hammer_reserve           *resv;
        struct hammer_inode             *ip;
        struct hammer_inode             *target_ip;
        struct hammer_btree_leaf_elm    leaf;
        union hammer_data_ondisk        *data;
        int                             flags;
};

typedef struct hammer_record *hammer_record_t;

/*
 * Record flags.  Note that FE can only be set by the frontend if the
 * record has not been interlocked by the backend w/ BE.
 */
#define HAMMER_RECF_ALLOCDATA           0x0001
#define HAMMER_RECF_ONRBTREE            0x0002
#define HAMMER_RECF_DELETED_FE          0x0004  /* deleted (frontend) */
#define HAMMER_RECF_DELETED_BE          0x0008  /* deleted (backend) */
#define HAMMER_RECF_UNUSED0010          0x0010
#define HAMMER_RECF_INTERLOCK_BE        0x0020  /* backend interlock */
#define HAMMER_RECF_WANTED              0x0040  /* wanted by the frontend */
#define HAMMER_RECF_CONVERT_DELETE      0x0100 /* special case */

/*
 * hammer_delete_at_cursor() flags
 */
#define HAMMER_DELETE_ADJUST            0x0001
#define HAMMER_DELETE_DESTROY           0x0002

/*
 * In-memory structures representing on-disk structures.
 */
struct hammer_volume;
struct hammer_buffer;
struct hammer_node;
struct hammer_undo;
struct hammer_reserve;

RB_HEAD(hammer_vol_rb_tree, hammer_volume);
RB_HEAD(hammer_buf_rb_tree, hammer_buffer);
RB_HEAD(hammer_nod_rb_tree, hammer_node);
RB_HEAD(hammer_und_rb_tree, hammer_undo);
RB_HEAD(hammer_res_rb_tree, hammer_reserve);

RB_PROTOTYPE2(hammer_vol_rb_tree, hammer_volume, rb_node,
              hammer_vol_rb_compare, int32_t);
RB_PROTOTYPE2(hammer_buf_rb_tree, hammer_buffer, rb_node,
              hammer_buf_rb_compare, hammer_off_t);
RB_PROTOTYPE2(hammer_nod_rb_tree, hammer_node, rb_node,
              hammer_nod_rb_compare, hammer_off_t);
RB_PROTOTYPE2(hammer_und_rb_tree, hammer_undo, rb_node,
              hammer_und_rb_compare, hammer_off_t);
RB_PROTOTYPE2(hammer_res_rb_tree, hammer_reserve, rb_node,
              hammer_res_rb_compare, hammer_off_t);

/*
 * IO management - embedded at the head of various in-memory structures
 *
 * VOLUME       - hammer_volume containing meta-data
 * META_BUFFER  - hammer_buffer containing meta-data
 * DATA_BUFFER  - hammer_buffer containing pure-data
 *
 * Dirty volume headers and dirty meta-data buffers are locked until the
 * flusher can sequence them out.  Dirty pure-data buffers can be written.
 * Clean buffers can be passively released.
 */
typedef enum hammer_io_type {
        HAMMER_STRUCTURE_VOLUME,
        HAMMER_STRUCTURE_META_BUFFER,
        HAMMER_STRUCTURE_UNDO_BUFFER,
        HAMMER_STRUCTURE_DATA_BUFFER
} hammer_io_type_t;

union hammer_io_structure;
struct hammer_io;

struct worklist {
        LIST_ENTRY(worklist) node;
};

TAILQ_HEAD(hammer_io_list, hammer_io);
typedef struct hammer_io_list *hammer_io_list_t;

struct hammer_io {
        struct worklist         worklist;
        struct hammer_lock      lock;
        enum hammer_io_type     type;
        struct hammer_mount     *hmp;
        TAILQ_ENTRY(hammer_io)  mod_entry; /* list entry if modified */
        hammer_io_list_t        mod_list;
        struct buf              *bp;
        int64_t                 offset;    /* zone-2 offset */
        int                     bytes;     /* buffer cache buffer size */
        int                     loading;   /* loading/unloading interlock */
        int                     modify_refs;

        u_int           modified : 1;   /* bp's data was modified */
        u_int           released : 1;   /* bp released (w/ B_LOCKED set) */
        u_int           running : 1;    /* bp write IO in progress */
        u_int           waiting : 1;    /* someone is waiting on us */
        u_int           validated : 1;  /* ondisk has been validated */
        u_int           waitdep : 1;    /* flush waits for dependancies */
        u_int           recovered : 1;  /* has recovery ref */
        u_int           waitmod : 1;    /* waiting for modify_refs */
        u_int           reclaim : 1;    /* reclaim requested */
        u_int           gencrc : 1;     /* crc needs to be generated */
};

typedef struct hammer_io *hammer_io_t;

#define HAMMER_CLUSTER_SIZE     (64 * 1024)
#if HAMMER_CLUSTER_SIZE > MAXBSIZE
#undef  HAMMER_CLUSTER_SIZE
#define HAMMER_CLUSTER_SIZE     MAXBSIZE
#endif
#define HAMMER_CLUSTER_BUFS     (HAMMER_CLUSTER_SIZE / HAMMER_BUFSIZE)

/*
 * In-memory volume representing on-disk buffer
 */
struct hammer_volume {
        struct hammer_io io;
        RB_ENTRY(hammer_volume) rb_node;
        struct hammer_volume_ondisk *ondisk;
        int32_t vol_no;
        int64_t nblocks;        /* note: special calculation for statfs */
        int64_t buffer_base;    /* base offset of buffer 0 */
        hammer_off_t maxbuf_off; /* Maximum buffer offset (zone-2) */
        hammer_off_t maxraw_off; /* Maximum raw offset for device */
        char    *vol_name;
        struct vnode *devvp;
        int     vol_flags;
};

typedef struct hammer_volume *hammer_volume_t;

/*
 * In-memory buffer (other then volume, super-cluster, or cluster),
 * representing an on-disk buffer.
 */
struct hammer_buffer {
        struct hammer_io io;
        RB_ENTRY(hammer_buffer) rb_node;
        void *ondisk;
        struct hammer_volume *volume;
        hammer_off_t zoneX_offset;
        hammer_off_t zone2_offset;
        struct hammer_reserve *resv;
        struct hammer_node_list clist;
};

typedef struct hammer_buffer *hammer_buffer_t;

/*
 * In-memory B-Tree node, representing an on-disk B-Tree node.
 *
 * This is a hang-on structure which is backed by a hammer_buffer,
 * indexed by a hammer_cluster, and used for fine-grained locking of
 * B-Tree nodes in order to properly control lock ordering.  A hammer_buffer
 * can contain multiple nodes representing wildly disassociated portions
 * of the B-Tree so locking cannot be done on a buffer-by-buffer basis.
 *
 * This structure uses a cluster-relative index to reduce the number
 * of layers required to access it, and also because all on-disk B-Tree
 * references are cluster-relative offsets.
 */
struct hammer_node {
        struct hammer_lock      lock;           /* node-by-node lock */
        TAILQ_ENTRY(hammer_node) entry;         /* per-buffer linkage */
        RB_ENTRY(hammer_node)   rb_node;        /* per-cluster linkage */
        hammer_off_t            node_offset;    /* full offset spec */
        struct hammer_mount     *hmp;
        struct hammer_buffer    *buffer;        /* backing buffer */
        hammer_node_ondisk_t    ondisk;         /* ptr to on-disk structure */
        struct hammer_node_cache_list cache_list; /* passive caches */
        int                     flags;
        int                     loading;        /* load interlock */
};

#define HAMMER_NODE_DELETED     0x0001
#define HAMMER_NODE_FLUSH       0x0002
#define HAMMER_NODE_CRCGOOD     0x0004
#define HAMMER_NODE_NEEDSCRC    0x0008
#define HAMMER_NODE_NEEDSMIRROR 0x0010

typedef struct hammer_node      *hammer_node_t;

/*
 * List of locked nodes.
 */
struct hammer_node_locklist {
        struct hammer_node_locklist *next;
        hammer_node_t   node;
};

typedef struct hammer_node_locklist *hammer_node_locklist_t;


/*
 * Common I/O management structure - embedded in in-memory structures
 * which are backed by filesystem buffers.
 */
union hammer_io_structure {
        struct hammer_io        io;
        struct hammer_volume    volume;
        struct hammer_buffer    buffer;
};

typedef union hammer_io_structure *hammer_io_structure_t;

/*
 * The reserve structure prevents the blockmap from allocating
 * out of a reserved bigblock.  Such reservations are used by
 * the direct-write mechanism.
 *
 * The structure is also used to hold off on reallocations of
 * big blocks from the freemap until flush dependancies have
 * been dealt with.
 */
struct hammer_reserve {
        RB_ENTRY(hammer_reserve) rb_node;
        TAILQ_ENTRY(hammer_reserve) delay_entry;
        int             flush_group;
        int             flags;
        int             refs;
        int             zone;
        int             append_off;
        hammer_off_t    zone_offset;
};

typedef struct hammer_reserve *hammer_reserve_t;

#define HAMMER_RESF_ONDELAY     0x0001

#include "hammer_cursor.h"

/*
 * The undo structure tracks recent undos to avoid laying down duplicate
 * undos within a flush group, saving us a significant amount of overhead.
 *
 * This is strictly a heuristic.
 */
#define HAMMER_MAX_UNDOS        1024
#define HAMMER_MAX_FLUSHERS     4

struct hammer_undo {
        RB_ENTRY(hammer_undo)   rb_node;
        TAILQ_ENTRY(hammer_undo) lru_entry;
        hammer_off_t            offset;
        int                     bytes;
};

typedef struct hammer_undo *hammer_undo_t;

struct hammer_flusher_info;

struct hammer_flusher {
        int             signal;         /* flusher thread sequencer */
        int             act;            /* currently active flush group */
        int             done;           /* set to act when complete */
        int             next;           /* next flush group */
        int             group_lock;     /* lock sequencing of the next flush */
        int             exiting;        /* request master exit */
        int             count;          /* number of slave flushers */
        int             running;        /* number of slave flushers running */
        thread_t        td;             /* master flusher thread */
        hammer_tid_t    tid;            /* last flushed transaction id */
        int             finalize_want;          /* serialize finalization */
        struct hammer_lock finalize_lock;       /* serialize finalization */
        struct hammer_transaction trans;        /* shared transaction */
        struct hammer_flusher_info *info[HAMMER_MAX_FLUSHERS];
};

/*
 * Internal hammer mount data structure
 */
struct hammer_mount {
        struct mount *mp;
        /*struct vnode *rootvp;*/
        struct hammer_ino_rb_tree rb_inos_root;
        struct hammer_vol_rb_tree rb_vols_root;
        struct hammer_nod_rb_tree rb_nods_root;
        struct hammer_und_rb_tree rb_undo_root;
        struct hammer_res_rb_tree rb_resv_root;
        struct hammer_buf_rb_tree rb_bufs_root;
        struct hammer_pfs_rb_tree rb_pfsm_root;
        struct hammer_volume *rootvol;
        struct hammer_base_elm root_btree_beg;
        struct hammer_base_elm root_btree_end;
        int     flags;
        int     hflags;
        int     ronly;
        int     nvolumes;
        int     volume_iterator;
        int     masterid;       /* -1 or 0-15 - clustering and mirroring */
        int     rsv_inodes;     /* reserved space due to dirty inodes */
        int64_t rsv_databytes;  /* reserved space due to record data */
        int     rsv_recs;       /* reserved space due to dirty records */
        int     rsv_fromdelay;  /* bigblocks reserved due to flush delay */
        int     last_newrecords;
        int     count_newrecords;

        int     inode_reclaims; /* inodes pending reclaim by flusher */
        int     count_inodes;   /* total number of inodes */
        int     count_iqueued;  /* inodes queued to flusher */

        struct hammer_flusher flusher;

        u_int   check_interrupt;
        uuid_t  fsid;
        udev_t  fsid_udev;
        struct hammer_io_list volu_list;        /* dirty undo buffers */
        struct hammer_io_list undo_list;        /* dirty undo buffers */
        struct hammer_io_list data_list;        /* dirty data buffers */
        struct hammer_io_list alt_data_list;    /* dirty data buffers */
        struct hammer_io_list meta_list;        /* dirty meta bufs    */
        struct hammer_io_list lose_list;        /* loose buffers      */
        int     locked_dirty_space;             /* meta/volu count    */
        int     io_running_space;
        int     objid_cache_count;
        hammer_tid_t    asof;                   /* snapshot mount */
        hammer_off_t    next_tid;
        int64_t copy_stat_freebigblocks;        /* number of free bigblocks */

        u_int32_t namekey_iterator;
        struct netexport export;
        struct hammer_lock sync_lock;
        struct hammer_lock free_lock;
        struct hammer_lock undo_lock;
        struct hammer_lock blkmap_lock;
        struct hammer_blockmap  blockmap[HAMMER_MAX_ZONES];
        struct hammer_undo      undos[HAMMER_MAX_UNDOS];
        int                     undo_alloc;
        TAILQ_HEAD(, hammer_undo)  undo_lru_list;
        TAILQ_HEAD(, hammer_inode) flush_list;
        TAILQ_HEAD(, hammer_reserve) delay_list;
        TAILQ_HEAD(, hammer_objid_cache) objid_cache_list;
        TAILQ_HEAD(, hammer_reclaim) reclaim_list;
};

typedef struct hammer_mount     *hammer_mount_t;

#define HAMMER_MOUNT_UNUSED0001 0x0001

struct hammer_sync_info {
        int error;
        int waitfor;
};

#endif

/*
 * checkspace slop (8MB chunks), higher numbers are more conservative.
 */
#define HAMMER_CHECKSPACE_SLOP_REBLOCK  25
#define HAMMER_CHECKSPACE_SLOP_WRITE    20
#define HAMMER_CHECKSPACE_SLOP_CREATE   15
#define HAMMER_CHECKSPACE_SLOP_REMOVE   10

#if defined(_KERNEL)

extern struct vop_ops hammer_vnode_vops;
extern struct vop_ops hammer_spec_vops;
extern struct vop_ops hammer_fifo_vops;
extern struct bio_ops hammer_bioops;

extern int hammer_debug_io;
extern int hammer_debug_general;
extern int hammer_debug_debug;
extern int hammer_debug_inode;
extern int hammer_debug_locks;
extern int hammer_debug_btree;
extern int hammer_debug_tid;
extern int hammer_debug_recover;
extern int hammer_debug_recover_faults;
extern int hammer_debug_cluster_enable;
extern int hammer_count_inodes;
extern int hammer_count_iqueued;
extern int hammer_count_reclaiming;
extern int hammer_count_records;
extern int hammer_count_record_datas;
extern int hammer_count_volumes;
extern int hammer_count_buffers;
extern int hammer_count_nodes;
extern int64_t hammer_count_extra_space_used;
extern int64_t hammer_stats_btree_lookups;
extern int64_t hammer_stats_btree_searches;
extern int64_t hammer_stats_btree_inserts;
extern int64_t hammer_stats_btree_deletes;
extern int64_t hammer_stats_btree_elements;
extern int64_t hammer_stats_btree_splits;
extern int64_t hammer_stats_btree_iterations;
extern int64_t hammer_stats_record_iterations;
extern int hammer_count_dirtybufspace;
extern int hammer_count_refedbufs;
extern int hammer_count_reservations;
extern int hammer_count_io_running_read;
extern int hammer_count_io_running_write;
extern int hammer_count_io_locked;
extern int hammer_limit_dirtybufspace;
extern int hammer_limit_iqueued;
extern int hammer_limit_recs;
extern int hammer_bio_count;
extern int hammer_verify_zone;
extern int hammer_write_mode;
extern int64_t hammer_contention_count;

int     hammer_vop_inactive(struct vop_inactive_args *);
int     hammer_vop_reclaim(struct vop_reclaim_args *);
int     hammer_get_vnode(struct hammer_inode *ip, struct vnode **vpp);
struct hammer_inode *hammer_get_inode(hammer_transaction_t trans,
                        hammer_inode_t dip, u_int64_t obj_id,
                        hammer_tid_t asof, u_int32_t localization,
                        int flags, int *errorp);
void    hammer_scan_inode_snapshots(hammer_mount_t hmp,
                        hammer_inode_info_t iinfo,
                        int (*callback)(hammer_inode_t ip, void *data),
                        void *data);
void    hammer_put_inode(struct hammer_inode *ip);
void    hammer_put_inode_ref(struct hammer_inode *ip);
void    hammer_inode_waitreclaims(hammer_mount_t hmp);

int     hammer_unload_volume(hammer_volume_t volume, void *data __unused);
int     hammer_adjust_volume_mode(hammer_volume_t volume, void *data __unused);

int     hammer_unload_buffer(hammer_buffer_t buffer, void *data __unused);
int     hammer_install_volume(hammer_mount_t hmp, const char *volname);

int     hammer_ip_lookup(hammer_cursor_t cursor);
int     hammer_ip_first(hammer_cursor_t cursor);
int     hammer_ip_next(hammer_cursor_t cursor);
int     hammer_ip_resolve_data(hammer_cursor_t cursor);
int     hammer_ip_delete_record(hammer_cursor_t cursor, hammer_inode_t ip,
                        hammer_tid_t tid);
int     hammer_delete_at_cursor(hammer_cursor_t cursor, int delete_flags,
                        int64_t *stat_bytes);
int     hammer_ip_check_directory_empty(hammer_transaction_t trans,
                        hammer_inode_t ip);
int     hammer_sync_hmp(hammer_mount_t hmp, int waitfor);
int     hammer_queue_inodes_flusher(hammer_mount_t hmp, int waitfor);

hammer_record_t
        hammer_alloc_mem_record(hammer_inode_t ip, int data_len);
void    hammer_flush_record_done(hammer_record_t record, int error);
void    hammer_wait_mem_record_ident(hammer_record_t record, const char *ident);
void    hammer_rel_mem_record(hammer_record_t record);

int     hammer_cursor_up(hammer_cursor_t cursor);
int     hammer_cursor_up_locked(hammer_cursor_t cursor);
int     hammer_cursor_down(hammer_cursor_t cursor);
int     hammer_cursor_upgrade(hammer_cursor_t cursor);
int     hammer_cursor_upgrade_node(hammer_cursor_t cursor);
void    hammer_cursor_downgrade(hammer_cursor_t cursor);
int     hammer_cursor_seek(hammer_cursor_t cursor, hammer_node_t node,
                        int index);
void    hammer_lock_ex_ident(struct hammer_lock *lock, const char *ident);
int     hammer_lock_ex_try(struct hammer_lock *lock);
void    hammer_lock_sh(struct hammer_lock *lock);
void    hammer_lock_sh_lowpri(struct hammer_lock *lock);
int     hammer_lock_sh_try(struct hammer_lock *lock);
int     hammer_lock_upgrade(struct hammer_lock *lock);
void    hammer_lock_downgrade(struct hammer_lock *lock);
void    hammer_unlock(struct hammer_lock *lock);
void    hammer_ref(struct hammer_lock *lock);
void    hammer_unref(struct hammer_lock *lock);

void    hammer_sync_lock_ex(hammer_transaction_t trans);
void    hammer_sync_lock_sh(hammer_transaction_t trans);
int     hammer_sync_lock_sh_try(hammer_transaction_t trans);
void    hammer_sync_unlock(hammer_transaction_t trans);

u_int32_t hammer_to_unix_xid(uuid_t *uuid);
void hammer_guid_to_uuid(uuid_t *uuid, u_int32_t guid);
void    hammer_time_to_timespec(u_int64_t xtime, struct timespec *ts);
u_int64_t hammer_timespec_to_time(struct timespec *ts);
hammer_tid_t hammer_str_to_tid(const char *str);
hammer_tid_t hammer_alloc_objid(hammer_mount_t hmp, hammer_inode_t dip);
void hammer_clear_objid(hammer_inode_t dip);
void hammer_destroy_objid_cache(hammer_mount_t hmp);

int hammer_enter_undo_history(hammer_mount_t hmp, hammer_off_t offset,
                              int bytes);
void hammer_clear_undo_history(hammer_mount_t hmp);
enum vtype hammer_get_vnode_type(u_int8_t obj_type);
int hammer_get_dtype(u_int8_t obj_type);
u_int8_t hammer_get_obj_type(enum vtype vtype);
int64_t hammer_directory_namekey(const void *name, int len);
int     hammer_nohistory(hammer_inode_t ip);

int     hammer_init_cursor(hammer_transaction_t trans, hammer_cursor_t cursor,
                           hammer_node_cache_t cache, hammer_inode_t ip);
int     hammer_reinit_cursor(hammer_cursor_t cursor);
void    hammer_normalize_cursor(hammer_cursor_t cursor);
void    hammer_done_cursor(hammer_cursor_t cursor);

int     hammer_btree_lookup(hammer_cursor_t cursor);
int     hammer_btree_first(hammer_cursor_t cursor);
int     hammer_btree_last(hammer_cursor_t cursor);
int     hammer_btree_extract(hammer_cursor_t cursor, int flags);
int     hammer_btree_iterate(hammer_cursor_t cursor);
int     hammer_btree_iterate_reverse(hammer_cursor_t cursor);
int     hammer_btree_insert(hammer_cursor_t cursor,
                            hammer_btree_leaf_elm_t elm, int *doprop);
int     hammer_btree_delete(hammer_cursor_t cursor);
void    hammer_btree_do_propagation(hammer_cursor_t cursor, hammer_inode_t ip,
                            hammer_btree_leaf_elm_t leaf);
int     hammer_btree_cmp(hammer_base_elm_t key1, hammer_base_elm_t key2);
int     hammer_btree_chkts(hammer_tid_t ts, hammer_base_elm_t key);
int     hammer_btree_correct_rhb(hammer_cursor_t cursor, hammer_tid_t tid);
int     hammer_btree_correct_lhb(hammer_cursor_t cursor, hammer_tid_t tid);

int     btree_set_parent(hammer_transaction_t trans, hammer_node_t node,
                        hammer_btree_elm_t elm);
int     hammer_btree_lock_children(hammer_cursor_t cursor,
                        struct hammer_node_locklist **locklistp);
void    hammer_btree_unlock_children(struct hammer_node_locklist **locklistp);
int     hammer_btree_search_node(hammer_base_elm_t elm, hammer_node_ondisk_t node);
hammer_node_t hammer_btree_get_parent(hammer_node_t node, int *parent_indexp,
                        int *errorp, int try_exclusive);

void    hammer_print_btree_node(hammer_node_ondisk_t ondisk);
void    hammer_print_btree_elm(hammer_btree_elm_t elm, u_int8_t type, int i);

void    *hammer_bread(struct hammer_mount *hmp, hammer_off_t off,
                        int *errorp, struct hammer_buffer **bufferp);
void    *hammer_bnew(struct hammer_mount *hmp, hammer_off_t off,
                        int *errorp, struct hammer_buffer **bufferp);
void    *hammer_bread_ext(struct hammer_mount *hmp, hammer_off_t off, int bytes,
                        int *errorp, struct hammer_buffer **bufferp);
void    *hammer_bnew_ext(struct hammer_mount *hmp, hammer_off_t off, int bytes,
                        int *errorp, struct hammer_buffer **bufferp);

hammer_volume_t hammer_get_root_volume(hammer_mount_t hmp, int *errorp);

hammer_volume_t hammer_get_volume(hammer_mount_t hmp,
                        int32_t vol_no, int *errorp);
hammer_buffer_t hammer_get_buffer(hammer_mount_t hmp, hammer_off_t buf_offset,
                        int bytes, int isnew, int *errorp);
void            hammer_del_buffers(hammer_mount_t hmp, hammer_off_t base_offset,
                        hammer_off_t zone2_offset, int bytes);

int             hammer_ref_volume(hammer_volume_t volume);
int             hammer_ref_buffer(hammer_buffer_t buffer);
void            hammer_flush_buffer_nodes(hammer_buffer_t buffer);

void            hammer_rel_volume(hammer_volume_t volume, int flush);
void            hammer_rel_buffer(hammer_buffer_t buffer, int flush);

int             hammer_vfs_export(struct mount *mp, int op,
                        const struct export_args *export);
hammer_node_t   hammer_get_node(hammer_mount_t hmp, hammer_off_t node_offset,
                        int isnew, int *errorp);
void            hammer_ref_node(hammer_node_t node);
hammer_node_t   hammer_ref_node_safe(struct hammer_mount *hmp,
                        hammer_node_cache_t cache, int *errorp);
void            hammer_rel_node(hammer_node_t node);
void            hammer_delete_node(hammer_transaction_t trans,
                        hammer_node_t node);
void            hammer_cache_node(hammer_node_cache_t cache,
                        hammer_node_t node);
void            hammer_uncache_node(hammer_node_cache_t cache);
void            hammer_flush_node(hammer_node_t node);

void hammer_dup_buffer(struct hammer_buffer **bufferp,
                        struct hammer_buffer *buffer);
hammer_node_t hammer_alloc_btree(hammer_transaction_t trans, int *errorp);
void *hammer_alloc_data(hammer_transaction_t trans, int32_t data_len,
                        u_int16_t rec_type, hammer_off_t *data_offsetp,
                        struct hammer_buffer **data_bufferp, int *errorp);

int hammer_generate_undo(hammer_transaction_t trans, hammer_io_t io,
                        hammer_off_t zone1_offset, void *base, int len);

void hammer_put_volume(struct hammer_volume *volume, int flush);
void hammer_put_buffer(struct hammer_buffer *buffer, int flush);

hammer_off_t hammer_freemap_alloc(hammer_transaction_t trans,
                        hammer_off_t owner, int *errorp);
void hammer_freemap_free(hammer_transaction_t trans, hammer_off_t phys_offset,
                        hammer_off_t owner, int *errorp);
int hammer_checkspace(hammer_mount_t hmp, int slop);
hammer_off_t hammer_blockmap_alloc(hammer_transaction_t trans, int zone,
                        int bytes, int *errorp);
hammer_reserve_t hammer_blockmap_reserve(hammer_mount_t hmp, int zone,
                        int bytes, hammer_off_t *zone_offp, int *errorp);
void hammer_blockmap_reserve_complete(hammer_mount_t hmp,
                        hammer_reserve_t resv);
void hammer_reserve_clrdelay(hammer_mount_t hmp, hammer_reserve_t resv);
void hammer_blockmap_free(hammer_transaction_t trans,
                        hammer_off_t bmap_off, int bytes);
void hammer_blockmap_finalize(hammer_transaction_t trans,
                        hammer_off_t bmap_off, int bytes);
int hammer_blockmap_getfree(hammer_mount_t hmp, hammer_off_t bmap_off,
                        int *curp, int *errorp);
hammer_off_t hammer_blockmap_lookup(hammer_mount_t hmp, hammer_off_t bmap_off,
                        int *errorp);
hammer_off_t hammer_undo_lookup(hammer_mount_t hmp, hammer_off_t bmap_off,
                        int *errorp);
int64_t hammer_undo_used(hammer_transaction_t trans);
int64_t hammer_undo_space(hammer_transaction_t trans);
int64_t hammer_undo_max(hammer_mount_t hmp);

void hammer_start_transaction(struct hammer_transaction *trans,
                              struct hammer_mount *hmp);
void hammer_simple_transaction(struct hammer_transaction *trans,
                              struct hammer_mount *hmp);
void hammer_start_transaction_fls(struct hammer_transaction *trans,
                                  struct hammer_mount *hmp);
void hammer_done_transaction(struct hammer_transaction *trans);

void hammer_modify_inode(hammer_inode_t ip, int flags);
void hammer_flush_inode(hammer_inode_t ip, int flags);
void hammer_flush_inode_done(hammer_inode_t ip);
void hammer_wait_inode(hammer_inode_t ip);

int  hammer_create_inode(struct hammer_transaction *trans, struct vattr *vap,
                        struct ucred *cred, struct hammer_inode *dip,
                        int pseudofs, struct hammer_inode **ipp);
void hammer_rel_inode(hammer_inode_t ip, int flush);
int hammer_reload_inode(hammer_inode_t ip, void *arg __unused);
int hammer_ino_rb_compare(hammer_inode_t ip1, hammer_inode_t ip2);

int hammer_sync_inode(hammer_inode_t ip);
void hammer_test_inode(hammer_inode_t ip);
void hammer_inode_unloadable_check(hammer_inode_t ip, int getvp);

int  hammer_ip_add_directory(struct hammer_transaction *trans,
                        hammer_inode_t dip, const char *name, int bytes,
                        hammer_inode_t nip);
int  hammer_ip_del_directory(struct hammer_transaction *trans,
                        hammer_cursor_t cursor, hammer_inode_t dip,
                        hammer_inode_t ip);
hammer_record_t hammer_ip_add_bulk(hammer_inode_t ip, off_t file_offset,
                        void *data, int bytes, int *errorp);
int  hammer_ip_frontend_trunc(struct hammer_inode *ip, off_t file_size);
int  hammer_ip_add_record(struct hammer_transaction *trans,
                        hammer_record_t record);
int  hammer_ip_delete_range(hammer_cursor_t cursor, hammer_inode_t ip,
                        int64_t ran_beg, int64_t ran_end, int truncating);
int  hammer_ip_delete_clean(hammer_cursor_t cursor, hammer_inode_t ip,
                        int *countp);
int  hammer_ip_sync_data(hammer_cursor_t cursor, hammer_inode_t ip,
                        int64_t offset, void *data, int bytes);
int  hammer_ip_sync_record(hammer_transaction_t trans, hammer_record_t rec);
int  hammer_ip_sync_record_cursor(hammer_cursor_t cursor, hammer_record_t rec);
int  hammer_load_pseudofs(hammer_transaction_t trans, hammer_inode_t ip);
int  hammer_save_pseudofs(hammer_transaction_t trans, hammer_inode_t ip);
void hammer_rel_pseudofs(hammer_mount_t hmp, hammer_pseudofs_inmem_t pfsm);
int hammer_ioctl(hammer_inode_t ip, u_long com, caddr_t data, int fflag,
                        struct ucred *cred);

void hammer_io_init(hammer_io_t io, hammer_mount_t hmp,
                        enum hammer_io_type type);
int hammer_io_read(struct vnode *devvp, struct hammer_io *io,
                        hammer_off_t limit);
int hammer_io_new(struct vnode *devvp, struct hammer_io *io);
void hammer_io_inval(hammer_volume_t volume, hammer_off_t zone2_offset);
struct buf *hammer_io_release(struct hammer_io *io, int flush);
void hammer_io_flush(struct hammer_io *io);
void hammer_io_waitdep(struct hammer_io *io);
void hammer_io_wait_all(hammer_mount_t hmp, const char *ident);
int hammer_io_direct_read(hammer_mount_t hmp, struct bio *bio);
int hammer_io_direct_write(hammer_mount_t hmp, hammer_btree_leaf_elm_t leaf,
                          struct bio *bio);
void hammer_io_direct_uncache(hammer_mount_t hmp, hammer_btree_leaf_elm_t leaf);
void hammer_io_write_interlock(hammer_io_t io);
void hammer_io_done_interlock(hammer_io_t io);
void hammer_io_clear_modify(struct hammer_io *io, int inval);
void hammer_io_clear_modlist(struct hammer_io *io);
void hammer_modify_volume(hammer_transaction_t trans, hammer_volume_t volume,
                        void *base, int len);
void hammer_modify_buffer(hammer_transaction_t trans, hammer_buffer_t buffer,
                        void *base, int len);
void hammer_modify_volume_done(hammer_volume_t volume);
void hammer_modify_buffer_done(hammer_buffer_t buffer);

int hammer_ioc_reblock(hammer_transaction_t trans, hammer_inode_t ip,
                        struct hammer_ioc_reblock *reblock);
int hammer_ioc_prune(hammer_transaction_t trans, hammer_inode_t ip,
                        struct hammer_ioc_prune *prune);
int hammer_ioc_mirror_read(hammer_transaction_t trans, hammer_inode_t ip,
                        struct hammer_ioc_mirror_rw *mirror);
int hammer_ioc_mirror_write(hammer_transaction_t trans, hammer_inode_t ip,
                        struct hammer_ioc_mirror_rw *mirror);
int hammer_ioc_set_pseudofs(hammer_transaction_t trans, hammer_inode_t ip,
                        struct hammer_ioc_pseudofs_rw *pfs);
int hammer_ioc_get_pseudofs(hammer_transaction_t trans, hammer_inode_t ip,
                        struct hammer_ioc_pseudofs_rw *pfs);

int hammer_signal_check(hammer_mount_t hmp);

void hammer_flusher_create(hammer_mount_t hmp);
void hammer_flusher_destroy(hammer_mount_t hmp);
void hammer_flusher_sync(hammer_mount_t hmp);
void hammer_flusher_async(hammer_mount_t hmp);
int  hammer_flusher_meta_limit(hammer_mount_t hmp);
int  hammer_flusher_undo_exhausted(hammer_transaction_t trans, int quarter);
void hammer_flusher_clean_loose_ios(hammer_mount_t hmp);

int hammer_recover(hammer_mount_t hmp, hammer_volume_t rootvol);
void hammer_recover_flush_buffers(hammer_mount_t hmp,
                        hammer_volume_t root_volume, int final);

void hammer_crc_set_blockmap(hammer_blockmap_t blockmap);
void hammer_crc_set_volume(hammer_volume_ondisk_t ondisk);
void hammer_crc_set_leaf(void *data, hammer_btree_leaf_elm_t leaf);

int hammer_crc_test_blockmap(hammer_blockmap_t blockmap);
int hammer_crc_test_volume(hammer_volume_ondisk_t ondisk);
int hammer_crc_test_btree(hammer_node_ondisk_t ondisk);
int hammer_crc_test_leaf(void *data, hammer_btree_leaf_elm_t leaf);
void hkprintf(const char *ctl, ...);

int hammer_blocksize(int64_t file_offset);
int64_t hammer_blockdemarc(int64_t file_offset1, int64_t file_offset2);

#endif

static __inline void
hammer_wait_mem_record(hammer_record_t record)
{
        hammer_wait_mem_record_ident(record, "hmmwai");
}

static __inline void
hammer_lock_ex(struct hammer_lock *lock)
{
        hammer_lock_ex_ident(lock, "hmrlck");
}

/*
 * Indicate that a B-Tree node is being modified.
 */
static __inline void
hammer_modify_node_noundo(hammer_transaction_t trans, hammer_node_t node)
{
        hammer_modify_buffer(trans, node->buffer, NULL, 0);
}

static __inline void
hammer_modify_node_all(hammer_transaction_t trans, struct hammer_node *node)
{
        hammer_modify_buffer(trans, node->buffer,
                             node->ondisk, sizeof(*node->ondisk));
}

static __inline void
hammer_modify_node(hammer_transaction_t trans, hammer_node_t node,
                   void *base, int len)
{
        hammer_crc_t *crcptr;

        KKASSERT((char *)base >= (char *)node->ondisk &&
                 (char *)base + len <=
                    (char *)node->ondisk + sizeof(*node->ondisk));
        hammer_modify_buffer(trans, node->buffer, base, len);
        crcptr = &node->ondisk->crc;
        hammer_modify_buffer(trans, node->buffer, crcptr, sizeof(hammer_crc_t));
        --node->buffer->io.modify_refs; /* only want one ref */
}

/*
 * Indicate that the specified modifications have been completed.
 *
 * Do not try to generate the crc here, it's very expensive to do and a
 * sequence of insertions or deletions can result in many calls to this
 * function on the same node.
 */
static __inline void
hammer_modify_node_done(hammer_node_t node)
{
        node->flags |= HAMMER_NODE_CRCGOOD;
        if ((node->flags & HAMMER_NODE_NEEDSCRC) == 0) {
                node->flags |= HAMMER_NODE_NEEDSCRC;
                node->buffer->io.gencrc = 1;
                hammer_ref_node(node);
        }
        hammer_modify_buffer_done(node->buffer);
}

#define hammer_modify_volume_field(trans, vol, field)           \
        hammer_modify_volume(trans, vol, &(vol)->ondisk->field, \
                             sizeof((vol)->ondisk->field))

#define hammer_modify_node_field(trans, node, field)            \
        hammer_modify_node(trans, node, &(node)->ondisk->field, \
                             sizeof((node)->ondisk->field))