hammer2 - refactor some chain bits, stabilization

[dragonfly.git] / sys / vfs / hammer2 / hammer2.h

/*
 * Copyright (c) 2011-2015 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@dragonflybsd.org>
 * by Venkatesh Srinivas <vsrinivas@dragonflybsd.org>
 *
 * 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.
 */

/*
 * HAMMER2 IN-MEMORY CACHE OF MEDIA STRUCTURES
 *
 * This header file contains structures used internally by the HAMMER2
 * implementation.  See hammer2_disk.h for on-disk structures.
 *
 * There is an in-memory representation of all on-media data structure.
 * Almost everything is represented by a hammer2_chain structure in-memory.
 * Other higher-level structures typically map to chains.
 *
 * A great deal of data is accessed simply via its buffer cache buffer,
 * which is mapped for the duration of the chain's lock.  Hammer2 must
 * implement its own buffer cache layer on top of the system layer to
 * allow for different threads to lock different sub-block-sized buffers.
 *
 * When modifications are made to a chain a new filesystem block must be
 * allocated.  Multiple modifications do not typically allocate new blocks
 * until the current block has been flushed.  Flushes do not block the
 * front-end unless the front-end operation crosses the current inode being
 * flushed.
 *
 * The in-memory representation may remain cached (for example in order to
 * placemark clustering locks) even after the related data has been
 * detached.
 */

#ifndef _VFS_HAMMER2_HAMMER2_H_
#define _VFS_HAMMER2_HAMMER2_H_

#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/vnode.h>
#include <sys/proc.h>
#include <sys/mountctl.h>
#include <sys/priv.h>
#include <sys/stat.h>
#include <sys/thread.h>
#include <sys/globaldata.h>
#include <sys/lockf.h>
#include <sys/buf.h>
#include <sys/queue.h>
#include <sys/limits.h>
#include <sys/dmsg.h>
#include <sys/mutex.h>
#include <sys/kern_syscall.h>

#include <sys/signal2.h>
#include <sys/buf2.h>
#include <sys/mutex2.h>
#include <sys/thread2.h>

#include "hammer2_disk.h"
#include "hammer2_mount.h"
#include "hammer2_ioctl.h"

struct hammer2_io;
struct hammer2_iocb;
struct hammer2_chain;
struct hammer2_cluster;
struct hammer2_inode;
struct hammer2_dev;
struct hammer2_pfs;
struct hammer2_span;
struct hammer2_state;
struct hammer2_msg;
struct hammer2_thread;
union hammer2_xop;

/*
 * Mutex and lock shims.  Hammer2 requires support for asynchronous and
 * abortable locks, and both exclusive and shared spinlocks.  Normal
 * synchronous non-abortable locks can be substituted for spinlocks.
 */
typedef mtx_t                           hammer2_mtx_t;
typedef mtx_link_t                      hammer2_mtx_link_t;
typedef mtx_state_t                     hammer2_mtx_state_t;

typedef struct spinlock                 hammer2_spin_t;

#define hammer2_mtx_ex                  mtx_lock_ex_quick
#define hammer2_mtx_sh                  mtx_lock_sh_quick
#define hammer2_mtx_unlock              mtx_unlock
#define hammer2_mtx_owned               mtx_owned
#define hammer2_mtx_init                mtx_init
#define hammer2_mtx_temp_release        mtx_lock_temp_release
#define hammer2_mtx_temp_restore        mtx_lock_temp_restore
#define hammer2_mtx_refs                mtx_lockrefs

#define hammer2_spin_init               spin_init
#define hammer2_spin_sh                 spin_lock_shared
#define hammer2_spin_ex                 spin_lock
#define hammer2_spin_unsh               spin_unlock_shared
#define hammer2_spin_unex               spin_unlock

TAILQ_HEAD(hammer2_xop_list, hammer2_xop_head);

typedef struct hammer2_xop_list hammer2_xop_list_t;


/*
 * General lock support
 */
static __inline
int
hammer2_mtx_upgrade(hammer2_mtx_t *mtx)
{
        int wasexclusive;

        if (mtx_islocked_ex(mtx)) {
                wasexclusive = 1;
        } else {
                mtx_unlock(mtx);
                mtx_lock_ex_quick(mtx);
                wasexclusive = 0;
        }
        return wasexclusive;
}

/*
 * Downgrade an inode lock from exclusive to shared only if the inode
 * lock was previously shared.  If the inode lock was previously exclusive,
 * this is a NOP.
 */
static __inline
void
hammer2_mtx_downgrade(hammer2_mtx_t *mtx, int wasexclusive)
{
        if (wasexclusive == 0)
                mtx_downgrade(mtx);
}

/*
 * The xid tracks internal transactional updates.
 *
 * XXX fix-me, really needs to be 64-bits
 */
typedef uint32_t hammer2_xid_t;

#define HAMMER2_XID_MIN 0x00000000U
#define HAMMER2_XID_MAX 0x7FFFFFFFU

/*
 * The chain structure tracks a portion of the media topology from the
 * root (volume) down.  Chains represent volumes, inodes, indirect blocks,
 * data blocks, and freemap nodes and leafs.
 *
 * The chain structure utilizes a simple singly-homed topology and the
 * chain's in-memory topology will move around as the chains do, due mainly
 * to renames and indirect block creation.
 *
 * Block Table Updates
 *
 *      Block table updates for insertions and updates are delayed until the
 *      flush.  This allows us to avoid having to modify the parent chain
 *      all the way to the root.
 *
 *      Block table deletions are performed immediately (modifying the parent
 *      in the process) because the flush code uses the chain structure to
 *      track delayed updates and the chain will be (likely) gone or moved to
 *      another location in the topology after a deletion.
 *
 *      A prior iteration of the code tried to keep the relationship intact
 *      on deletes by doing a delete-duplicate operation on the chain, but
 *      it added way too much complexity to the codebase.
 *
 * Flush Synchronization
 *
 *      The flush code must flush modified chains bottom-up.  Because chain
 *      structures can shift around and are NOT topologically stable,
 *      modified chains are independently indexed for the flush.  As the flush
 *      runs it modifies (or further modifies) and updates the parents,
 *      propagating the flush all the way to the volume root.
 *
 *      Modifying front-end operations can occur during a flush but will block
 *      in two cases: (1) when the front-end tries to operate on the inode
 *      currently in the midst of being flushed and (2) if the front-end
 *      crosses an inode currently being flushed (such as during a rename).
 *      So, for example, if you rename directory "x" to "a/b/c/d/e/f/g/x" and
 *      the flusher is currently working on "a/b/c", the rename will block
 *      temporarily in order to ensure that "x" exists in one place or the
 *      other.
 *
 *      Meta-data statistics are updated by the flusher.  The front-end will
 *      make estimates but meta-data must be fully synchronized only during a
 *      flush in order to ensure that it remains correct across a crash.
 *
 *      Multiple flush synchronizations can theoretically be in-flight at the
 *      same time but the implementation is not coded to handle the case and
 *      currently serializes them.
 *
 * Snapshots:
 *
 *      Snapshots currently require the subdirectory tree being snapshotted
 *      to be flushed.  The snapshot then creates a new super-root inode which
 *      copies the flushed blockdata of the directory or file that was
 *      snapshotted.
 *
 * RBTREE NOTES:
 *
 *      - Note that the radix tree runs in powers of 2 only so sub-trees
 *        cannot straddle edges.
 */
RB_HEAD(hammer2_chain_tree, hammer2_chain);
TAILQ_HEAD(h2_flush_list, hammer2_chain);
TAILQ_HEAD(h2_core_list, hammer2_chain);
TAILQ_HEAD(h2_iocb_list, hammer2_iocb);

#define CHAIN_CORE_DELETE_BMAP_ENTRIES  \
        (HAMMER2_PBUFSIZE / sizeof(hammer2_blockref_t) / sizeof(uint32_t))

/*
 * Core topology for chain (embedded in chain).  Protected by a spinlock.
 */
struct hammer2_chain_core {
        hammer2_spin_t  spin;
        struct hammer2_chain_tree rbtree; /* sub-chains */
        int             live_zero;      /* blockref array opt */
        u_int           live_count;     /* live (not deleted) chains in tree */
        u_int           chain_count;    /* live + deleted chains under core */
        int             generation;     /* generation number (inserts only) */
};

typedef struct hammer2_chain_core hammer2_chain_core_t;

RB_HEAD(hammer2_io_tree, hammer2_io);

/*
 * IOCB - IO callback (into chain, cluster, or manual request)
 */
struct hammer2_iocb {
        TAILQ_ENTRY(hammer2_iocb) entry;
        void (*callback)(struct hammer2_iocb *iocb);
        struct hammer2_io       *dio;
        struct hammer2_cluster  *cluster;
        struct hammer2_chain    *chain;
        void                    *ptr;
        off_t                   lbase;
        int                     lsize;
        uint32_t                flags;
        int                     error;
};

typedef struct hammer2_iocb hammer2_iocb_t;

#define HAMMER2_IOCB_INTERLOCK  0x00000001
#define HAMMER2_IOCB_ONQ        0x00000002
#define HAMMER2_IOCB_DONE       0x00000004
#define HAMMER2_IOCB_INPROG     0x00000008
#define HAMMER2_IOCB_UNUSED10   0x00000010
#define HAMMER2_IOCB_QUICK      0x00010000
#define HAMMER2_IOCB_ZERO       0x00020000
#define HAMMER2_IOCB_READ       0x00040000
#define HAMMER2_IOCB_WAKEUP     0x00080000

/*
 * DIO - Management structure wrapping system buffer cache.
 *
 *       Used for multiple purposes including concurrent management
 *       if small requests by chains into larger DIOs.
 */
struct hammer2_io {
        RB_ENTRY(hammer2_io) rbnode;    /* indexed by device offset */
        struct h2_iocb_list iocbq;
        struct spinlock spin;
        struct hammer2_dev *hmp;
        struct buf      *bp;
        off_t           pbase;
        int             psize;
        int             refs;
        int             act;                    /* activity */
};

typedef struct hammer2_io hammer2_io_t;

#define HAMMER2_DIO_INPROG      0x80000000      /* bio in progress */
#define HAMMER2_DIO_GOOD        0x40000000      /* dio->bp is stable */
#define HAMMER2_DIO_WAITING     0x20000000      /* (old) */
#define HAMMER2_DIO_DIRTY       0x10000000      /* flush on last drop */

#define HAMMER2_DIO_MASK        0x0FFFFFFF

/*
 * Primary chain structure keeps track of the topology in-memory.
 */
struct hammer2_chain {
        hammer2_mtx_t           lock;
        hammer2_chain_core_t    core;
        RB_ENTRY(hammer2_chain) rbnode;         /* live chain(s) */
        hammer2_blockref_t      bref;
        struct hammer2_chain    *parent;
        struct hammer2_state    *state;         /* if active cache msg */
        struct hammer2_dev      *hmp;
        struct hammer2_pfs      *pmp;           /* A PFS or super-root (spmp) */

        hammer2_io_t    *dio;                   /* physical data buffer */
        u_int           bytes;                  /* physical data size */
        u_int           flags;
        u_int           refs;
        u_int           lockcnt;
        int             error;                  /* on-lock data error state */

        hammer2_media_data_t *data;             /* data pointer shortcut */
        TAILQ_ENTRY(hammer2_chain) flush_node;  /* flush list */
};

typedef struct hammer2_chain hammer2_chain_t;

int hammer2_chain_cmp(hammer2_chain_t *chain1, hammer2_chain_t *chain2);
RB_PROTOTYPE(hammer2_chain_tree, hammer2_chain, rbnode, hammer2_chain_cmp);

/*
 * Special notes on flags:
 *
 * INITIAL      - This flag allows a chain to be created and for storage to
 *                be allocated without having to immediately instantiate the
 *                related buffer.  The data is assumed to be all-zeros.  It
 *                is primarily used for indirect blocks.
 *
 * MODIFIED     - The chain's media data has been modified.  Prevents chain
 *                free on lastdrop if still in the topology.
 *
 * UPDATE       - Chain might not be modified but parent blocktable needs
 *                an update.  Prevents chain free on lastdrop if still in
 *                the topology.
 *
 * FICTITIOUS   - Faked chain as a placeholder for an error condition.  This
 *                chain is unsuitable for I/O.
 *
 * BMAPPED      - Indicates that the chain is present in the parent blockmap.
 *
 * BMAPUPD      - Indicates that the chain is present but needs to be updated
 *                in the parent blockmap.
 */
#define HAMMER2_CHAIN_MODIFIED          0x00000001      /* dirty chain data */
#define HAMMER2_CHAIN_ALLOCATED         0x00000002      /* kmalloc'd chain */
#define HAMMER2_CHAIN_DESTROY           0x00000004
#define HAMMER2_CHAIN_DEDUP             0x00000008      /* used as dedup src */
#define HAMMER2_CHAIN_DELETED           0x00000010      /* deleted chain */
#define HAMMER2_CHAIN_INITIAL           0x00000020      /* initial create */
#define HAMMER2_CHAIN_UPDATE            0x00000040      /* need parent update */
#define HAMMER2_CHAIN_DEFERRED          0x00000080      /* flush depth defer */
#define HAMMER2_CHAIN_UNUSED000001000   0x00000100
#define HAMMER2_CHAIN_ONFLUSH           0x00000200      /* on a flush list */
#define HAMMER2_CHAIN_FICTITIOUS        0x00000400      /* unsuitable for I/O */
#define HAMMER2_CHAIN_VOLUMESYNC        0x00000800      /* needs volume sync */
#define HAMMER2_CHAIN_DELAYED           0x00001000      /* delayed flush */
#define HAMMER2_CHAIN_COUNTEDBREFS      0x00002000      /* block table stats */
#define HAMMER2_CHAIN_ONRBTREE          0x00004000      /* on parent RB tree */
#define HAMMER2_CHAIN_UNUSED00008000    0x00008000
#define HAMMER2_CHAIN_EMBEDDED          0x00010000      /* embedded data */
#define HAMMER2_CHAIN_RELEASE           0x00020000      /* don't keep around */
#define HAMMER2_CHAIN_BMAPPED           0x00040000      /* present in blkmap */
#define HAMMER2_CHAIN_BMAPUPD           0x00080000      /* +needs updating */
#define HAMMER2_CHAIN_IOINPROG          0x00100000      /* I/O interlock */
#define HAMMER2_CHAIN_IOSIGNAL          0x00200000      /* I/O interlock */
#define HAMMER2_CHAIN_PFSBOUNDARY       0x00400000      /* super->pfs inode */

#define HAMMER2_CHAIN_FLUSH_MASK        (HAMMER2_CHAIN_MODIFIED |       \
                                         HAMMER2_CHAIN_UPDATE |         \
                                         HAMMER2_CHAIN_ONFLUSH)

/*
 * Hammer2 error codes, used by chain->error and cluster->error.  The error
 * code is typically set on-lock unless no I/O was requested, and set on
 * I/O otherwise.  If set for a cluster it generally means that the cluster
 * code could not find a valid copy to present.
 *
 * IO           - An I/O error occurred
 * CHECK        - I/O succeeded but did not match the check code
 * INCOMPLETE   - A cluster is not complete enough to use, or
 *                a chain cannot be loaded because its parent has an error.
 *
 * NOTE: API allows callers to check zero/non-zero to determine if an error
 *       condition exists.
 *
 * NOTE: Chain's data field is usually NULL on an IO error but not necessarily
 *       NULL on other errors.  Check chain->error, not chain->data.
 */
#define HAMMER2_ERROR_NONE              0
#define HAMMER2_ERROR_IO                1       /* device I/O error */
#define HAMMER2_ERROR_CHECK             2       /* check code mismatch */
#define HAMMER2_ERROR_INCOMPLETE        3       /* incomplete cluster */
#define HAMMER2_ERROR_DEPTH             4       /* temporary depth limit */

/*
 * Flags passed to hammer2_chain_lookup() and hammer2_chain_next()
 *
 * NOTES:
 *      NOLOCK      - Input and output chains are referenced only and not
 *                    locked.  Output chain might be temporarily locked
 *                    internally.
 *
 *      NODATA      - Asks that the chain->data not be resolved in order
 *                    to avoid I/O.
 *
 *      NODIRECT    - Prevents a lookup of offset 0 in an inode from returning
 *                    the inode itself if the inode is in DIRECTDATA mode
 *                    (i.e. file is <= 512 bytes).  Used by the synchronization
 *                    code to prevent confusion.
 *
 *      SHARED      - The input chain is expected to be locked shared,
 *                    and the output chain is locked shared.
 *
 *      MATCHIND    - Allows an indirect block / freemap node to be returned
 *                    when the passed key range matches the radix.  Remember
 *                    that key_end is inclusive (e.g. {0x000,0xFFF},
 *                    not {0x000,0x1000}).
 *
 *                    (Cannot be used for remote or cluster ops).
 *
 *      ALLNODES    - Allows NULL focus.
 *
 *      ALWAYS      - Always resolve the data.  If ALWAYS and NODATA are both
 *                    missing, bulk file data is not resolved but inodes and
 *                    other meta-data will.
 *
 *      NOUNLOCK    - Used by hammer2_chain_next() to leave the lock on
 *                    the input chain intact.  The chain is still dropped.
 *                    This allows the caller to add a reference to the chain
 *                    and retain it in a locked state (used by the
 *                    XOP/feed/collect code).
 */
#define HAMMER2_LOOKUP_NOLOCK           0x00000001      /* ref only */
#define HAMMER2_LOOKUP_NODATA           0x00000002      /* data left NULL */
#define HAMMER2_LOOKUP_NODIRECT         0x00000004      /* no offset=0 DD */
#define HAMMER2_LOOKUP_SHARED           0x00000100
#define HAMMER2_LOOKUP_MATCHIND         0x00000200      /* return all chains */
#define HAMMER2_LOOKUP_ALLNODES         0x00000400      /* allow NULL focus */
#define HAMMER2_LOOKUP_ALWAYS           0x00000800      /* resolve data */
#define HAMMER2_LOOKUP_NOUNLOCK         0x00001000      /* leave lock intact */

/*
 * Flags passed to hammer2_chain_modify() and hammer2_chain_resize()
 *
 * NOTE: OPTDATA allows us to avoid instantiating buffers for INDIRECT
 *       blocks in the INITIAL-create state.
 */
#define HAMMER2_MODIFY_OPTDATA          0x00000002      /* data can be NULL */
#define HAMMER2_MODIFY_NO_MODIFY_TID    0x00000004
#define HAMMER2_MODIFY_UNUSED0008       0x00000008

/*
 * Flags passed to hammer2_chain_lock()
 *
 * NOTE: RDONLY is set to optimize cluster operations when *no* modifications
 *       will be made to either the cluster being locked or any underlying
 *       cluster.  It allows the cluster to lock and access data for a subset
 *       of available nodes instead of all available nodes.
 */
#define HAMMER2_RESOLVE_NEVER           1
#define HAMMER2_RESOLVE_MAYBE           2
#define HAMMER2_RESOLVE_ALWAYS          3
#define HAMMER2_RESOLVE_MASK            0x0F

#define HAMMER2_RESOLVE_SHARED          0x10    /* request shared lock */
#define HAMMER2_RESOLVE_UNUSED20        0x20
#define HAMMER2_RESOLVE_RDONLY          0x40    /* higher level op flag */

/*
 * Flags passed to hammer2_chain_delete()
 */
#define HAMMER2_DELETE_PERMANENT        0x0001

/*
 * Flags passed to hammer2_chain_insert() or hammer2_chain_rename()
 */
#define HAMMER2_INSERT_PFSROOT          0x0004

/*
 * Flags passed to hammer2_chain_delete_duplicate()
 */
#define HAMMER2_DELDUP_RECORE           0x0001

/*
 * Cluster different types of storage together for allocations
 */
#define HAMMER2_FREECACHE_INODE         0
#define HAMMER2_FREECACHE_INDIR         1
#define HAMMER2_FREECACHE_DATA          2
#define HAMMER2_FREECACHE_UNUSED3       3
#define HAMMER2_FREECACHE_TYPES         4

/*
 * hammer2_freemap_alloc() block preference
 */
#define HAMMER2_OFF_NOPREF              ((hammer2_off_t)-1)

/*
 * BMAP read-ahead maximum parameters
 */
#define HAMMER2_BMAP_COUNT              16      /* max bmap read-ahead */
#define HAMMER2_BMAP_BYTES              (HAMMER2_PBUFSIZE * HAMMER2_BMAP_COUNT)

/*
 * hammer2_freemap_adjust()
 */
#define HAMMER2_FREEMAP_DORECOVER       1
#define HAMMER2_FREEMAP_DOMAYFREE       2
#define HAMMER2_FREEMAP_DOREALFREE      3

/*
 * HAMMER2 cluster - A set of chains representing the same entity.
 *
 * hammer2_cluster typically represents a temporary set of representitive
 * chains.  The one exception is that a hammer2_cluster is embedded in
 * hammer2_inode.  This embedded cluster is ONLY used to track the
 * representitive chains and cannot be directly locked.
 *
 * A cluster is usually temporary (and thus per-thread) for locking purposes,
 * allowing us to embed the asynchronous storage required for cluster
 * operations in the cluster itself and adjust the state and status without
 * having to worry too much about SMP issues.
 *
 * The exception is the cluster embedded in the hammer2_inode structure.
 * This is used to cache the cluster state on an inode-by-inode basis.
 * Individual hammer2_chain structures not incorporated into clusters might
 * also stick around to cache miscellanious elements.
 *
 * Because the cluster is a 'working copy' and is usually subject to cluster
 * quorum rules, it is quite possible for us to end up with an insufficient
 * number of live chains to execute an operation.  If an insufficient number
 * of chains remain in a working copy, the operation may have to be
 * downgraded, retried, stall until the requisit number of chains are
 * available, or possibly even error out depending on the mount type.
 *
 * A cluster's focus is set when it is locked.  The focus can only be set
 * to a chain still part of the synchronized set.
 */
#define HAMMER2_MAXCLUSTER      8
#define HAMMER2_XOPFIFO         16
#define HAMMER2_XOPFIFO_MASK    (HAMMER2_XOPFIFO - 1)
#define HAMMER2_XOPGROUPS       16
#define HAMMER2_XOPGROUPS_MASK  (HAMMER2_XOPGROUPS - 1)
#define HAMMER2_XOPMASK_VOP     0x80000000U

struct hammer2_cluster_item {
        hammer2_chain_t         *chain;
        int                     cache_index;
        int                     error;
        uint32_t                flags;
};

typedef struct hammer2_cluster_item hammer2_cluster_item_t;

/*
 * INVALID      - Invalid for focus, i.e. not part of synchronized set.
 *                Once set, this bit is sticky across operations.
 *
 * FEMOD        - Indicates that front-end modifying operations can
 *                mess with this entry and MODSYNC will copy also
 *                effect it.
 */
#define HAMMER2_CITEM_INVALID   0x00000001
#define HAMMER2_CITEM_FEMOD     0x00000002
#define HAMMER2_CITEM_NULL      0x00000004

struct hammer2_cluster {
        int                     refs;           /* track for deallocation */
        int                     ddflag;
        struct hammer2_pfs      *pmp;
        uint32_t                flags;
        int                     nchains;
        int                     error;          /* error code valid on lock */
        int                     focus_index;
        hammer2_iocb_t          iocb;
        hammer2_chain_t         *focus;         /* current focus (or mod) */
        hammer2_cluster_item_t  array[HAMMER2_MAXCLUSTER];
};

typedef struct hammer2_cluster  hammer2_cluster_t;

/*
 * WRHARD       - Hard mounts can write fully synchronized
 * RDHARD       - Hard mounts can read fully synchronized
 * UNHARD       - Unsynchronized masters present
 * NOHARD       - No masters visible
 * WRSOFT       - Soft mounts can write to at least the SOFT_MASTER
 * RDSOFT       - Soft mounts can read from at least a SOFT_SLAVE
 * UNSOFT       - Unsynchronized slaves present
 * NOSOFT       - No slaves visible
 * RDSLAVE      - slaves are accessible (possibly unsynchronized or remote).
 * MSYNCED      - All masters are fully synchronized
 * SSYNCED      - All known local slaves are fully synchronized to masters
 *
 * All available masters are always incorporated.  All PFSs belonging to a
 * cluster (master, slave, copy, whatever) always try to synchronize the
 * total number of known masters in the PFSs root inode.
 *
 * A cluster might have access to many slaves, copies, or caches, but we
 * have a limited number of cluster slots.  Any such elements which are
 * directly mounted from block device(s) will always be incorporated.   Note
 * that SSYNCED only applies to such elements which are directly mounted,
 * not to any remote slaves, copies, or caches that could be available.  These
 * bits are used to monitor and drive our synchronization threads.
 *
 * When asking the question 'is any data accessible at all', then a simple
 * test against (RDHARD|RDSOFT|RDSLAVE) gives you the answer.  If any of
 * these bits are set the object can be read with certain caveats:
 * RDHARD - no caveats.  RDSOFT - authoritative but might not be synchronized.
 * and RDSLAVE - not authoritative, has some data but it could be old or
 * incomplete.
 *
 * When both soft and hard mounts are available, data will be read and written
 * via the soft mount only.  But all might be in the cluster because
 * background synchronization threads still need to do their work.
 */
#define HAMMER2_CLUSTER_INODE   0x00000001      /* embedded in inode struct */
#define HAMMER2_CLUSTER_UNUSED2 0x00000002
#define HAMMER2_CLUSTER_LOCKED  0x00000004      /* cluster lks not recursive */
#define HAMMER2_CLUSTER_WRHARD  0x00000100      /* hard-mount can write */
#define HAMMER2_CLUSTER_RDHARD  0x00000200      /* hard-mount can read */
#define HAMMER2_CLUSTER_UNHARD  0x00000400      /* unsynchronized masters */
#define HAMMER2_CLUSTER_NOHARD  0x00000800      /* no masters visible */
#define HAMMER2_CLUSTER_WRSOFT  0x00001000      /* soft-mount can write */
#define HAMMER2_CLUSTER_RDSOFT  0x00002000      /* soft-mount can read */
#define HAMMER2_CLUSTER_UNSOFT  0x00004000      /* unsynchronized slaves */
#define HAMMER2_CLUSTER_NOSOFT  0x00008000      /* no slaves visible */
#define HAMMER2_CLUSTER_MSYNCED 0x00010000      /* all masters synchronized */
#define HAMMER2_CLUSTER_SSYNCED 0x00020000      /* known slaves synchronized */

#define HAMMER2_CLUSTER_ANYDATA ( HAMMER2_CLUSTER_RDHARD |      \
                                  HAMMER2_CLUSTER_RDSOFT |      \
                                  HAMMER2_CLUSTER_RDSLAVE)

#define HAMMER2_CLUSTER_RDOK    ( HAMMER2_CLUSTER_RDHARD |      \
                                  HAMMER2_CLUSTER_RDSOFT)

#define HAMMER2_CLUSTER_WROK    ( HAMMER2_CLUSTER_WRHARD |      \
                                  HAMMER2_CLUSTER_WRSOFT)

#define HAMMER2_CLUSTER_ZFLAGS  ( HAMMER2_CLUSTER_WRHARD |      \
                                  HAMMER2_CLUSTER_RDHARD |      \
                                  HAMMER2_CLUSTER_WRSOFT |      \
                                  HAMMER2_CLUSTER_RDSOFT |      \
                                  HAMMER2_CLUSTER_MSYNCED |     \
                                  HAMMER2_CLUSTER_SSYNCED)

/*
 * Helper functions (cluster must be locked for flags to be valid).
 */
static __inline
int
hammer2_cluster_rdok(hammer2_cluster_t *cluster)
{
        return (cluster->flags & HAMMER2_CLUSTER_RDOK);
}

static __inline
int
hammer2_cluster_wrok(hammer2_cluster_t *cluster)
{
        return (cluster->flags & HAMMER2_CLUSTER_WROK);
}

RB_HEAD(hammer2_inode_tree, hammer2_inode);

/*
 * A hammer2 inode.
 *
 * NOTE: The inode-embedded cluster is never used directly for I/O (since
 *       it may be shared).  Instead it will be replicated-in and synchronized
 *       back out if changed.
 */
struct hammer2_inode {
        RB_ENTRY(hammer2_inode) rbnode;         /* inumber lookup (HL) */
        hammer2_mtx_t           lock;           /* inode lock */
        struct hammer2_pfs      *pmp;           /* PFS mount */
        struct hammer2_inode    *pip;           /* parent inode */
        struct vnode            *vp;
        struct spinlock         cluster_spin;   /* update cluster */
        hammer2_cluster_t       cluster;
        struct lockf            advlock;
        u_int                   flags;
        u_int                   refs;           /* +vpref, +flushref */
        uint8_t                 comp_heuristic;
        hammer2_inode_meta_t    meta;           /* copy of meta-data */
        hammer2_off_t           osize;
};

typedef struct hammer2_inode hammer2_inode_t;

/*
 * MODIFIED     - Inode is in a modified state, ip->meta may have changes.
 * RESIZED      - Inode truncated (any) or inode extended beyond
 *                EMBEDDED_BYTES.
 */
#define HAMMER2_INODE_MODIFIED          0x0001
#define HAMMER2_INODE_SROOT             0x0002  /* kmalloc special case */
#define HAMMER2_INODE_RENAME_INPROG     0x0004
#define HAMMER2_INODE_ONRBTREE          0x0008
#define HAMMER2_INODE_RESIZED           0x0010  /* requires inode_fsync */
#define HAMMER2_INODE_ISDELETED         0x0020  /* deleted, not in ihidden */
#define HAMMER2_INODE_ISUNLINKED        0x0040
#define HAMMER2_INODE_METAGOOD          0x0080  /* inode meta-data good */
#define HAMMER2_INODE_ONSIDEQ           0x0100  /* on side processing queue */

int hammer2_inode_cmp(hammer2_inode_t *ip1, hammer2_inode_t *ip2);
RB_PROTOTYPE2(hammer2_inode_tree, hammer2_inode, rbnode, hammer2_inode_cmp,
                hammer2_tid_t);

/*
 * inode-unlink side-structure
 */
struct hammer2_inode_sideq {
        TAILQ_ENTRY(hammer2_inode_sideq) entry;
        hammer2_inode_t *ip;
};
TAILQ_HEAD(h2_sideq_list, hammer2_inode_sideq);

typedef struct hammer2_inode_sideq hammer2_inode_sideq_t;

/*
 * Transaction management sub-structure under hammer2_pfs
 */
struct hammer2_trans {
        uint32_t                flags;
        uint32_t                sync_wait;
};

typedef struct hammer2_trans hammer2_trans_t;

#define HAMMER2_TRANS_ISFLUSH           0x80000000      /* flush code */
#define HAMMER2_TRANS_BUFCACHE          0x40000000      /* bio strategy */
#define HAMMER2_TRANS_PREFLUSH          0x20000000      /* preflush state */
#define HAMMER2_TRANS_FPENDING          0x10000000      /* flush pending */
#define HAMMER2_TRANS_WAITING           0x08000000      /* someone waiting */
#define HAMMER2_TRANS_MASK              0x00FFFFFF      /* count mask */

#define HAMMER2_FREEMAP_HEUR_NRADIX     4       /* pwr 2 PBUFRADIX-MINIORADIX */
#define HAMMER2_FREEMAP_HEUR_TYPES      8
#define HAMMER2_FREEMAP_HEUR_SIZE       (HAMMER2_FREEMAP_HEUR_NRADIX * \
                                         HAMMER2_FREEMAP_HEUR_TYPES)

#define HAMMER2_DEDUP_HEUR_SIZE         65536
#define HAMMER2_DEDUP_HEUR_MASK         (HAMMER2_DEDUP_HEUR_SIZE - 1)

#define HAMMER2_FLUSH_TOP               0x0001
#define HAMMER2_FLUSH_ALL               0x0002


/*
 * Hammer2 support thread element.
 *
 * Potentially many support threads can hang off of hammer2, primarily
 * off the hammer2_pfs structure.  Typically:
 *
 * td x Nodes                   A synchronization thread for each node.
 * td x Nodes x workers         Worker threads for frontend operations.
 * td x 1                       Bioq thread for logical buffer writes.
 *
 * In addition, the synchronization thread(s) associated with the
 * super-root PFS (spmp) for a node is responsible for automatic bulkfree
 * and dedup scans.
 */
struct hammer2_thread {
        struct hammer2_pfs *pmp;
        hammer2_xop_list_t *xopq;       /* points into pmp->xopq[] */
        thread_t        td;
        uint32_t        flags;
        int             depth;
        int             clindex;        /* cluster element index */
        int             repidx;
        struct lock     lk;             /* thread control lock */
};

typedef struct hammer2_thread hammer2_thread_t;

#define HAMMER2_THREAD_UNMOUNTING       0x0001  /* unmount request */
#define HAMMER2_THREAD_DEV              0x0002  /* related to dev, not pfs */
#define HAMMER2_THREAD_UNUSED04         0x0004
#define HAMMER2_THREAD_REMASTER         0x0008  /* remaster request */
#define HAMMER2_THREAD_STOP             0x0010  /* exit request */
#define HAMMER2_THREAD_FREEZE           0x0020  /* force idle */
#define HAMMER2_THREAD_FROZEN           0x0040  /* restart */

/*
 * Support structure for dedup heuristic.
 */
struct hammer2_dedup {
        hammer2_off_t   data_off;
        uint32_t        data_crc;
        uint32_t        ticks;
};

typedef struct hammer2_dedup hammer2_dedup_t;

/*
 * hammer2_xop - container for VOP/XOP operation (allocated, not on stack).
 *
 * This structure is used to distribute a VOP operation across multiple
 * nodes.  It provides a rendezvous for concurrent node execution and
 * can be detached from the frontend operation to allow the frontend to
 * return early.
 *
 * This structure also sequences operations on up to three inodes.
 */
typedef void (*hammer2_xop_func_t)(union hammer2_xop *xop, int clidx);

struct hammer2_xop_fifo {
        TAILQ_ENTRY(hammer2_xop_head) entry;
        hammer2_chain_t         *array[HAMMER2_XOPFIFO];
        int                     errors[HAMMER2_XOPFIFO];
        int                     ri;
        int                     wi;
        int                     flags;
};

typedef struct hammer2_xop_fifo hammer2_xop_fifo_t;

#define HAMMER2_XOP_FIFO_RUN    0x0001

struct hammer2_xop_head {
        hammer2_xop_func_t      func;
        hammer2_tid_t           mtid;
        struct hammer2_inode    *ip1;
        struct hammer2_inode    *ip2;
        struct hammer2_inode    *ip3;
        uint32_t                check_counter;
        uint32_t                run_mask;
        uint32_t                chk_mask;
        int                     state;
        int                     error;
        hammer2_key_t           collect_key;
        char                    *name1;
        size_t                  name1_len;
        char                    *name2;
        size_t                  name2_len;
        hammer2_xop_fifo_t      collect[HAMMER2_MAXCLUSTER];
        hammer2_cluster_t       cluster;        /* help collections */
};

typedef struct hammer2_xop_head hammer2_xop_head_t;

struct hammer2_xop_ipcluster {
        hammer2_xop_head_t      head;
};

struct hammer2_xop_strategy {
        hammer2_xop_head_t      head;
        hammer2_key_t           lbase;
        int                     finished;
        hammer2_mtx_t           lock;
        struct bio              *bio;
};

struct hammer2_xop_readdir {
        hammer2_xop_head_t      head;
        hammer2_key_t           lkey;
};

struct hammer2_xop_nresolve {
        hammer2_xop_head_t      head;
        hammer2_key_t           lhc;    /* if name is NULL used lhc */
};

struct hammer2_xop_nlink {
        hammer2_xop_head_t      head;
        int                     nlinks_delta;
};

struct hammer2_xop_unlink {
        hammer2_xop_head_t      head;
        int                     isdir;
        int                     dopermanent;
};

struct hammer2_xop_nrename {
        hammer2_xop_head_t      head;
        hammer2_tid_t           lhc;
        int                     ip_key;
};

struct hammer2_xop_scanlhc {
        hammer2_xop_head_t      head;
        hammer2_key_t           lhc;
};

struct hammer2_xop_scanall {
        hammer2_xop_head_t      head;
        hammer2_key_t           key_beg;        /* inclusive */
        hammer2_key_t           key_end;        /* inclusive */
};

struct hammer2_xop_lookup {
        hammer2_xop_head_t      head;
        hammer2_key_t           lhc;
};

struct hammer2_xop_create {
        hammer2_xop_head_t      head;
        hammer2_inode_meta_t    meta;           /* initial metadata */
        hammer2_key_t           lhc;
        int                     flags;
};

struct hammer2_xop_destroy {
        hammer2_xop_head_t      head;
};

struct hammer2_xop_fsync {
        hammer2_xop_head_t      head;
        hammer2_inode_meta_t    meta;
        hammer2_off_t           osize;
        u_int                   ipflags;
        int                     clear_directdata;
};

struct hammer2_xop_unlinkall {
        hammer2_xop_head_t      head;
        hammer2_key_t           key_beg;
        hammer2_key_t           key_end;
};

struct hammer2_xop_connect {
        hammer2_xop_head_t      head;
        hammer2_key_t           lhc;
};

struct hammer2_xop_flush {
        hammer2_xop_head_t      head;
};

typedef struct hammer2_xop_readdir hammer2_xop_readdir_t;
typedef struct hammer2_xop_nresolve hammer2_xop_nresolve_t;
typedef struct hammer2_xop_nlink hammer2_xop_nlink_t;
typedef struct hammer2_xop_unlink hammer2_xop_unlink_t;
typedef struct hammer2_xop_nrename hammer2_xop_nrename_t;
typedef struct hammer2_xop_ipcluster hammer2_xop_ipcluster_t;
typedef struct hammer2_xop_strategy hammer2_xop_strategy_t;
typedef struct hammer2_xop_create hammer2_xop_create_t;
typedef struct hammer2_xop_destroy hammer2_xop_destroy_t;
typedef struct hammer2_xop_fsync hammer2_xop_fsync_t;
typedef struct hammer2_xop_unlinkall hammer2_xop_unlinkall_t;
typedef struct hammer2_xop_scanlhc hammer2_xop_scanlhc_t;
typedef struct hammer2_xop_scanall hammer2_xop_scanall_t;
typedef struct hammer2_xop_lookup hammer2_xop_lookup_t;
typedef struct hammer2_xop_connect hammer2_xop_connect_t;
typedef struct hammer2_xop_flush hammer2_xop_flush_t;

union hammer2_xop {
        hammer2_xop_head_t      head;
        hammer2_xop_ipcluster_t xop_ipcluster;
        hammer2_xop_readdir_t   xop_readdir;
        hammer2_xop_nresolve_t  xop_nresolve;
        hammer2_xop_nlink_t     xop_nlink;
        hammer2_xop_unlink_t    xop_unlink;
        hammer2_xop_nrename_t   xop_nrename;
        hammer2_xop_strategy_t  xop_strategy;
        hammer2_xop_create_t    xop_create;
        hammer2_xop_destroy_t   xop_destroy;
        hammer2_xop_fsync_t     xop_fsync;
        hammer2_xop_unlinkall_t xop_unlinkall;
        hammer2_xop_scanlhc_t   xop_scanlhc;
        hammer2_xop_scanall_t   xop_scanall;
        hammer2_xop_lookup_t    xop_lookup;
        hammer2_xop_flush_t     xop_flush;
        hammer2_xop_connect_t   xop_connect;
};

typedef union hammer2_xop hammer2_xop_t;

/*
 * hammer2_xop_group - Manage XOP support threads.
 */
struct hammer2_xop_group {
        hammer2_thread_t        thrs[HAMMER2_MAXCLUSTER];
};

typedef struct hammer2_xop_group hammer2_xop_group_t;

/*
 * flags to hammer2_xop_collect()
 */
#define HAMMER2_XOP_COLLECT_NOWAIT      0x00000001
#define HAMMER2_XOP_COLLECT_WAITALL     0x00000002

/*
 * flags to hammer2_xop_alloc()
 *
 * MODIFYING    - This is a modifying transaction, allocate a mtid.
 */
#define HAMMER2_XOP_MODIFYING           0x00000001

/*
 * Global (per partition) management structure, represents a hard block
 * device.  Typically referenced by hammer2_chain structures when applicable.
 * Typically not used for network-managed elements.
 *
 * Note that a single hammer2_dev can be indirectly tied to multiple system
 * mount points.  There is no direct relationship.  System mounts are
 * per-cluster-id, not per-block-device, and a single hard mount might contain
 * many PFSs and those PFSs might combine together in various ways to form
 * the set of available clusters.
 */
struct hammer2_dev {
        struct vnode    *devvp;         /* device vnode */
        int             ronly;          /* read-only mount */
        int             mount_count;    /* number of actively mounted PFSs */
        TAILQ_ENTRY(hammer2_dev) mntentry; /* hammer2_mntlist */

        struct malloc_type *mchain;
        int             nipstacks;
        int             maxipstacks;
        kdmsg_iocom_t   iocom;          /* volume-level dmsg interface */
        struct spinlock io_spin;        /* iotree access */
        struct hammer2_io_tree iotree;
        int             iofree_count;
        hammer2_chain_t vchain;         /* anchor chain (topology) */
        hammer2_chain_t fchain;         /* anchor chain (freemap) */
        struct spinlock list_spin;
        struct h2_flush_list    flushq; /* flush seeds */
        struct hammer2_pfs *spmp;       /* super-root pmp for transactions */
        struct lock     bulklk;         /* bulkfree lock */
        struct lock     vollk;          /* lockmgr lock */
        hammer2_off_t   heur_freemap[HAMMER2_FREEMAP_HEUR_SIZE];
        hammer2_dedup_t heur_dedup[HAMMER2_DEDUP_HEUR_SIZE];
        int             volhdrno;       /* last volhdrno written */
        char            devrepname[64]; /* for kprintf */
        hammer2_volume_data_t voldata;
        hammer2_volume_data_t volsync;  /* synchronized voldata */
};

typedef struct hammer2_dev hammer2_dev_t;

/*
 * Helper functions (cluster must be locked for flags to be valid).
 */
static __inline
int
hammer2_chain_rdok(hammer2_chain_t *chain)
{
        return (chain->error == 0);
}

static __inline
int
hammer2_chain_wrok(hammer2_chain_t *chain)
{
        return (chain->error == 0 && chain->hmp->ronly == 0);
}

/*
 * Per-cluster management structure.  This structure will be tied to a
 * system mount point if the system is mounting the PFS, but is also used
 * to manage clusters encountered during the super-root scan or received
 * via LNK_SPANs that might not be mounted.
 *
 * This structure is also used to represent the super-root that hangs off
 * of a hard mount point.  The super-root is not really a cluster element.
 * In this case the spmp_hmp field will be non-NULL.  It's just easier to do
 * this than to special case super-root manipulation in the hammer2_chain*
 * code as being only hammer2_dev-related.
 *
 * pfs_mode and pfs_nmasters are rollup fields which critically describes
 * how elements of the cluster act on the cluster.  pfs_mode is only applicable
 * when a PFS is mounted by the system.  pfs_nmasters is our best guess as to
 * how many masters have been configured for a cluster and is always
 * applicable.  pfs_types[] is an array with 1:1 correspondance to the
 * iroot cluster and describes the PFS types of the nodes making up the
 * cluster.
 *
 * WARNING! Portions of this structure have deferred initialization.  In
 *          particular, if not mounted there will be no ihidden or wthread.
 *          umounted network PFSs will also be missing iroot and numerous
 *          other fields will not be initialized prior to mount.
 *
 *          Synchronization threads are chain-specific and only applicable
 *          to local hard PFS entries.  A hammer2_pfs structure may contain
 *          more than one when multiple hard PFSs are present on the local
 *          machine which require synchronization monitoring.  Most PFSs
 *          (such as snapshots) are 1xMASTER PFSs which do not need a
 *          synchronization thread.
 *
 * WARNING! The chains making up pfs->iroot's cluster are accounted for in
 *          hammer2_dev->mount_count when the pfs is associated with a mount
 *          point.
 */
struct hammer2_pfs {
        struct mount            *mp;
        TAILQ_ENTRY(hammer2_pfs) mntentry;      /* hammer2_pfslist */
        uuid_t                  pfs_clid;
        hammer2_dev_t           *spmp_hmp;      /* only if super-root pmp */
        hammer2_inode_t         *iroot;         /* PFS root inode */
        hammer2_inode_t         *ihidden;       /* PFS hidden directory */
        uint8_t                 pfs_types[HAMMER2_MAXCLUSTER];
        char                    *pfs_names[HAMMER2_MAXCLUSTER];
        hammer2_dev_t           *pfs_hmps[HAMMER2_MAXCLUSTER];
        hammer2_trans_t         trans;
        struct lock             lock;           /* PFS lock for certain ops */
        struct lock             lock_nlink;     /* rename and nlink lock */
        struct netexport        export;         /* nfs export */
        int                     ronly;          /* read-only mount */
        struct malloc_type      *minode;
        struct malloc_type      *mmsg;
        struct spinlock         inum_spin;      /* inumber lookup */
        struct hammer2_inode_tree inum_tree;    /* (not applicable to spmp) */
        hammer2_tid_t           modify_tid;     /* modify transaction id */
        hammer2_tid_t           inode_tid;      /* inode allocator */
        uint8_t                 pfs_nmasters;   /* total masters */
        uint8_t                 pfs_mode;       /* operating mode PFSMODE */
        uint8_t                 unused01;
        uint8_t                 unused02;
        int                     xop_iterator;
        long                    inmem_inodes;
        uint32_t                inmem_dirty_chains;
        int                     count_lwinprog; /* logical write in prog */
        struct spinlock         list_spin;
        struct h2_sideq_list    sideq;          /* last-close dirty/unlink */
        hammer2_thread_t        sync_thrs[HAMMER2_MAXCLUSTER];
        uint32_t                cluster_flags;  /* cached cluster flags */
        int                     has_xop_threads;
        struct spinlock         xop_spin;       /* xop sequencer */
        hammer2_xop_group_t     xop_groups[HAMMER2_XOPGROUPS];
        hammer2_xop_list_t      xopq[HAMMER2_MAXCLUSTER];
};

typedef struct hammer2_pfs hammer2_pfs_t;

#define HAMMER2_DIRTYCHAIN_WAITING      0x80000000
#define HAMMER2_DIRTYCHAIN_MASK         0x7FFFFFFF

#define HAMMER2_LWINPROG_WAITING        0x80000000
#define HAMMER2_LWINPROG_WAITING0       0x40000000
#define HAMMER2_LWINPROG_MASK           0x3FFFFFFF

/*
 * hammer2_cluster_check
 */
#define HAMMER2_CHECK_NULL      0x00000001

/*
 * Bulkscan
 */
#define HAMMER2_BULK_ABORT      0x00000001

/*
 * Misc
 */
#if defined(_KERNEL)

MALLOC_DECLARE(M_HAMMER2);

#define VTOI(vp)        ((hammer2_inode_t *)(vp)->v_data)
#define ITOV(ip)        ((ip)->vp)

/*
 * Currently locked chains retain the locked buffer cache buffer for
 * indirect blocks, and indirect blocks can be one of two sizes.  The
 * device buffer has to match the case to avoid deadlocking recursive
 * chains that might otherwise try to access different offsets within
 * the same device buffer.
 */
static __inline
int
hammer2_devblkradix(int radix)
{
#if 0
        if (radix <= HAMMER2_LBUFRADIX) {
                return (HAMMER2_LBUFRADIX);
        } else {
                return (HAMMER2_PBUFRADIX);
        }
#endif
        return (HAMMER2_PBUFRADIX);
}

/*
 * XXX almost time to remove this.  DIO uses PBUFSIZE exclusively now.
 */
static __inline
size_t
hammer2_devblksize(size_t bytes)
{
#if 0
        if (bytes <= HAMMER2_LBUFSIZE) {
                return(HAMMER2_LBUFSIZE);
        } else {
                KKASSERT(bytes <= HAMMER2_PBUFSIZE &&
                         (bytes ^ (bytes - 1)) == ((bytes << 1) - 1));
                return (HAMMER2_PBUFSIZE);
        }
#endif
        return (HAMMER2_PBUFSIZE);
}


static __inline
hammer2_pfs_t *
MPTOPMP(struct mount *mp)
{
        return ((hammer2_pfs_t *)mp->mnt_data);
}

#define LOCKSTART       int __nlocks = curthread->td_locks
#define LOCKENTER       (++curthread->td_locks)
#define LOCKEXIT        (--curthread->td_locks)
#define LOCKSTOP        KKASSERT(curthread->td_locks == __nlocks)

extern struct vop_ops hammer2_vnode_vops;
extern struct vop_ops hammer2_spec_vops;
extern struct vop_ops hammer2_fifo_vops;

extern int hammer2_debug;
extern int hammer2_cluster_enable;
extern int hammer2_hardlink_enable;
extern int hammer2_flush_pipe;
extern int hammer2_synchronous_flush;
extern int hammer2_dio_count;
extern long hammer2_limit_dirty_chains;
extern long hammer2_count_modified_chains;
extern long hammer2_iod_file_read;
extern long hammer2_iod_meta_read;
extern long hammer2_iod_indr_read;
extern long hammer2_iod_fmap_read;
extern long hammer2_iod_volu_read;
extern long hammer2_iod_file_write;
extern long hammer2_iod_file_wembed;
extern long hammer2_iod_file_wzero;
extern long hammer2_iod_file_wdedup;
extern long hammer2_iod_meta_write;
extern long hammer2_iod_indr_write;
extern long hammer2_iod_fmap_write;
extern long hammer2_iod_volu_write;
extern long hammer2_ioa_file_read;
extern long hammer2_ioa_meta_read;
extern long hammer2_ioa_indr_read;
extern long hammer2_ioa_fmap_read;
extern long hammer2_ioa_volu_read;
extern long hammer2_ioa_file_write;
extern long hammer2_ioa_meta_write;
extern long hammer2_ioa_indr_write;
extern long hammer2_ioa_fmap_write;
extern long hammer2_ioa_volu_write;

extern struct objcache *cache_buffer_read;
extern struct objcache *cache_buffer_write;
extern struct objcache *cache_xops;

/*
 * hammer2_subr.c
 */
#define hammer2_icrc32(buf, size)       iscsi_crc32((buf), (size))
#define hammer2_icrc32c(buf, size, crc) iscsi_crc32_ext((buf), (size), (crc))

int hammer2_signal_check(time_t *timep);
const char *hammer2_error_str(int error);

void hammer2_inode_lock(hammer2_inode_t *ip, int how);
void hammer2_inode_unlock(hammer2_inode_t *ip);
hammer2_chain_t *hammer2_inode_chain(hammer2_inode_t *ip, int clindex, int how);
hammer2_chain_t *hammer2_inode_chain_and_parent(hammer2_inode_t *ip,
                        int clindex, hammer2_chain_t **parentp, int how);
hammer2_mtx_state_t hammer2_inode_lock_temp_release(hammer2_inode_t *ip);
void hammer2_inode_lock_temp_restore(hammer2_inode_t *ip,
                        hammer2_mtx_state_t ostate);
int hammer2_inode_lock_upgrade(hammer2_inode_t *ip);
void hammer2_inode_lock_downgrade(hammer2_inode_t *ip, int);

void hammer2_dev_exlock(hammer2_dev_t *hmp);
void hammer2_dev_shlock(hammer2_dev_t *hmp);
void hammer2_dev_unlock(hammer2_dev_t *hmp);

int hammer2_get_dtype(const hammer2_inode_data_t *ipdata);
int hammer2_get_vtype(uint8_t type);
u_int8_t hammer2_get_obj_type(enum vtype vtype);
void hammer2_time_to_timespec(u_int64_t xtime, struct timespec *ts);
u_int64_t hammer2_timespec_to_time(const struct timespec *ts);
u_int32_t hammer2_to_unix_xid(const uuid_t *uuid);
void hammer2_guid_to_uuid(uuid_t *uuid, u_int32_t guid);
void hammer2_trans_manage_init(hammer2_pfs_t *pmp);

hammer2_key_t hammer2_dirhash(const unsigned char *name, size_t len);
int hammer2_getradix(size_t bytes);

int hammer2_calc_logical(hammer2_inode_t *ip, hammer2_off_t uoff,
                        hammer2_key_t *lbasep, hammer2_key_t *leofp);
int hammer2_calc_physical(hammer2_inode_t *ip, hammer2_key_t lbase);
void hammer2_update_time(uint64_t *timep);
void hammer2_adjreadcounter(hammer2_blockref_t *bref, size_t bytes);

/*
 * hammer2_inode.c
 */
struct vnode *hammer2_igetv(hammer2_inode_t *ip, int *errorp);
hammer2_inode_t *hammer2_inode_lookup(hammer2_pfs_t *pmp,
                        hammer2_tid_t inum);
hammer2_inode_t *hammer2_inode_get(hammer2_pfs_t *pmp, hammer2_inode_t *dip,
                        hammer2_cluster_t *cluster, int idx);
void hammer2_inode_free(hammer2_inode_t *ip);
void hammer2_inode_ref(hammer2_inode_t *ip);
void hammer2_inode_drop(hammer2_inode_t *ip);
void hammer2_inode_repoint(hammer2_inode_t *ip, hammer2_inode_t *pip,
                        hammer2_cluster_t *cluster);
void hammer2_inode_repoint_one(hammer2_inode_t *ip, hammer2_cluster_t *cluster,
                        int idx);
void hammer2_inode_modify(hammer2_inode_t *ip);
void hammer2_inode_run_sideq(hammer2_pfs_t *pmp);

hammer2_inode_t *hammer2_inode_create(hammer2_inode_t *dip,
                        struct vattr *vap, struct ucred *cred,
                        const uint8_t *name, size_t name_len, hammer2_key_t lhc,
                        hammer2_key_t inum, uint8_t type, uint8_t target_type,
                        int flags, int *errorp);
int hammer2_inode_connect(hammer2_inode_t *dip, hammer2_inode_t *ip,
                        const char *name, size_t name_len,
                        hammer2_key_t lhc);
hammer2_inode_t *hammer2_inode_common_parent(hammer2_inode_t *fdip,
                        hammer2_inode_t *tdip);
void hammer2_inode_chain_sync(hammer2_inode_t *ip);
int hammer2_inode_unlink_finisher(hammer2_inode_t *ip, int isopen);
void hammer2_inode_install_hidden(hammer2_pfs_t *pmp);

/*
 * hammer2_chain.c
 */
void hammer2_voldata_lock(hammer2_dev_t *hmp);
void hammer2_voldata_unlock(hammer2_dev_t *hmp);
void hammer2_voldata_modify(hammer2_dev_t *hmp);
hammer2_chain_t *hammer2_chain_alloc(hammer2_dev_t *hmp,
                                hammer2_pfs_t *pmp,
                                hammer2_blockref_t *bref);
void hammer2_chain_core_init(hammer2_chain_t *chain);
void hammer2_chain_ref(hammer2_chain_t *chain);
void hammer2_chain_drop(hammer2_chain_t *chain);
void hammer2_chain_lock(hammer2_chain_t *chain, int how);
void hammer2_chain_push_shared_lock(hammer2_chain_t *chain);
void hammer2_chain_pull_shared_lock(hammer2_chain_t *chain);
void hammer2_chain_load_data(hammer2_chain_t *chain);
const hammer2_media_data_t *hammer2_chain_rdata(hammer2_chain_t *chain);
hammer2_media_data_t *hammer2_chain_wdata(hammer2_chain_t *chain);
int hammer2_chain_snapshot(hammer2_chain_t *chain, hammer2_ioc_pfs_t *pmp,
                                hammer2_tid_t mtid);

int hammer2_chain_hardlink_find(hammer2_inode_t *dip,
                                hammer2_chain_t **parentp,
                                hammer2_chain_t **chainp,
                                int flags);
void hammer2_chain_modify(hammer2_chain_t *chain, hammer2_tid_t mtid,
                                hammer2_off_t dedup_off, int flags);
void hammer2_chain_modify_ip(hammer2_inode_t *ip, hammer2_chain_t *chain,
                                hammer2_tid_t mtid, int flags);
void hammer2_chain_resize(hammer2_inode_t *ip, hammer2_chain_t *parent,
                                hammer2_chain_t *chain,
                                hammer2_tid_t mtid, hammer2_off_t dedup_off,
                                int nradix, int flags);
void hammer2_chain_unlock(hammer2_chain_t *chain);
void hammer2_chain_wait(hammer2_chain_t *chain);
hammer2_chain_t *hammer2_chain_get(hammer2_chain_t *parent, int generation,
                                hammer2_blockref_t *bref);
hammer2_chain_t *hammer2_chain_lookup_init(hammer2_chain_t *parent, int flags);
void hammer2_chain_lookup_done(hammer2_chain_t *parent);
hammer2_chain_t *hammer2_chain_getparent(hammer2_chain_t **parentp, int how);
hammer2_chain_t *hammer2_chain_lookup(hammer2_chain_t **parentp,
                                hammer2_key_t *key_nextp,
                                hammer2_key_t key_beg, hammer2_key_t key_end,
                                int *cache_indexp, int flags);
hammer2_chain_t *hammer2_chain_next(hammer2_chain_t **parentp,
                                hammer2_chain_t *chain,
                                hammer2_key_t *key_nextp,
                                hammer2_key_t key_beg, hammer2_key_t key_end,
                                int *cache_indexp, int flags);
hammer2_blockref_t *hammer2_chain_scan(hammer2_chain_t *parent,
                                hammer2_chain_t **chainp,
                                hammer2_blockref_t *bref,
                                int *firstp, int *cache_indexp, int flags);

int hammer2_chain_create(hammer2_chain_t **parentp,
                                hammer2_chain_t **chainp, hammer2_pfs_t *pmp,
                                hammer2_key_t key, int keybits,
                                int type, size_t bytes, hammer2_tid_t mtid,
                                hammer2_off_t dedup_off, int flags);
void hammer2_chain_rename(hammer2_blockref_t *bref,
                                hammer2_chain_t **parentp,
                                hammer2_chain_t *chain,
                                hammer2_tid_t mtid, int flags);
void hammer2_chain_delete(hammer2_chain_t *parent, hammer2_chain_t *chain,
                                hammer2_tid_t mtid, int flags);
void hammer2_chain_setflush(hammer2_chain_t *chain);
void hammer2_chain_countbrefs(hammer2_chain_t *chain,
                                hammer2_blockref_t *base, int count);
hammer2_chain_t *hammer2_chain_bulksnap(hammer2_chain_t *chain);
void hammer2_chain_bulkdrop(hammer2_chain_t *copy);

void hammer2_chain_setcheck(hammer2_chain_t *chain, void *bdata);
int hammer2_chain_testcheck(hammer2_chain_t *chain, void *bdata);


void hammer2_pfs_memory_wait(hammer2_pfs_t *pmp);
void hammer2_pfs_memory_inc(hammer2_pfs_t *pmp);
void hammer2_pfs_memory_wakeup(hammer2_pfs_t *pmp);

void hammer2_base_delete(hammer2_chain_t *chain,
                                hammer2_blockref_t *base, int count,
                                int *cache_indexp, hammer2_chain_t *child);
void hammer2_base_insert(hammer2_chain_t *chain,
                                hammer2_blockref_t *base, int count,
                                int *cache_indexp, hammer2_chain_t *child);

/*
 * hammer2_flush.c
 */
void hammer2_flush(hammer2_chain_t *chain, int istop);
void hammer2_flush_quick(hammer2_dev_t *hmp);
void hammer2_delayed_flush(hammer2_chain_t *chain);

/*
 * hammer2_trans.c
 */
void hammer2_trans_init(hammer2_pfs_t *pmp, uint32_t flags);
hammer2_tid_t hammer2_trans_sub(hammer2_pfs_t *pmp);
void hammer2_trans_clear_preflush(hammer2_pfs_t *pmp);
void hammer2_trans_done(hammer2_pfs_t *pmp);
hammer2_tid_t hammer2_trans_newinum(hammer2_pfs_t *pmp);
void hammer2_trans_assert_strategy(hammer2_pfs_t *pmp);

/*
 * hammer2_ioctl.c
 */
int hammer2_ioctl(hammer2_inode_t *ip, u_long com, void *data,
                                int fflag, struct ucred *cred);

/*
 * hammer2_io.c
 */
void hammer2_io_putblk(hammer2_io_t **diop);
void hammer2_io_cleanup(hammer2_dev_t *hmp, struct hammer2_io_tree *tree);
char *hammer2_io_data(hammer2_io_t *dio, off_t lbase);
hammer2_io_t *hammer2_io_getquick(hammer2_dev_t *hmp, off_t lbase, int lsize);
void hammer2_io_getblk(hammer2_dev_t *hmp, off_t lbase, int lsize,
                                hammer2_iocb_t *iocb);
void hammer2_io_complete(hammer2_iocb_t *iocb);
void hammer2_io_callback(struct bio *bio);
void hammer2_iocb_wait(hammer2_iocb_t *iocb);
int hammer2_io_new(hammer2_dev_t *hmp, off_t lbase, int lsize,
                                hammer2_io_t **diop);
int hammer2_io_newnz(hammer2_dev_t *hmp, off_t lbase, int lsize,
                                hammer2_io_t **diop);
int hammer2_io_newq(hammer2_dev_t *hmp, off_t lbase, int lsize,
                                hammer2_io_t **diop);
int hammer2_io_bread(hammer2_dev_t *hmp, off_t lbase, int lsize,
                                hammer2_io_t **diop);
void hammer2_io_bawrite(hammer2_io_t **diop);
void hammer2_io_bdwrite(hammer2_io_t **diop);
int hammer2_io_bwrite(hammer2_io_t **diop);
int hammer2_io_isdirty(hammer2_io_t *dio);
void hammer2_io_setdirty(hammer2_io_t *dio);
void hammer2_io_setinval(hammer2_io_t *dio, u_int bytes);
void hammer2_io_brelse(hammer2_io_t **diop);
void hammer2_io_bqrelse(hammer2_io_t **diop);

/*
 * hammer2_thread.c
 */
void hammer2_thr_create(hammer2_thread_t *thr, hammer2_pfs_t *pmp,
                        const char *id, int clindex, int repidx,
                        void (*func)(void *arg));
void hammer2_thr_delete(hammer2_thread_t *thr);
void hammer2_thr_remaster(hammer2_thread_t *thr);
void hammer2_thr_freeze_async(hammer2_thread_t *thr);
void hammer2_thr_freeze(hammer2_thread_t *thr);
void hammer2_thr_unfreeze(hammer2_thread_t *thr);
int hammer2_thr_break(hammer2_thread_t *thr);
void hammer2_primary_xops_thread(void *arg);

/*
 * hammer2_thread.c (XOP API)
 */
void hammer2_xop_group_init(hammer2_pfs_t *pmp, hammer2_xop_group_t *xgrp);
void *hammer2_xop_alloc(hammer2_inode_t *ip, int flags);
void hammer2_xop_setname(hammer2_xop_head_t *xop,
                                const char *name, size_t name_len);
void hammer2_xop_setname2(hammer2_xop_head_t *xop,
                                const char *name, size_t name_len);
void hammer2_xop_setip2(hammer2_xop_head_t *xop, hammer2_inode_t *ip2);
void hammer2_xop_setip3(hammer2_xop_head_t *xop, hammer2_inode_t *ip3);
void hammer2_xop_reinit(hammer2_xop_head_t *xop);
void hammer2_xop_helper_create(hammer2_pfs_t *pmp);
void hammer2_xop_helper_cleanup(hammer2_pfs_t *pmp);
void hammer2_xop_start(hammer2_xop_head_t *xop, hammer2_xop_func_t func);
void hammer2_xop_start_except(hammer2_xop_head_t *xop, hammer2_xop_func_t func,
                                int notidx);
int hammer2_xop_collect(hammer2_xop_head_t *xop, int flags);
void hammer2_xop_retire(hammer2_xop_head_t *xop, uint32_t mask);
int hammer2_xop_active(hammer2_xop_head_t *xop);
int hammer2_xop_feed(hammer2_xop_head_t *xop, hammer2_chain_t *chain,
                                int clindex, int error);

/*
 * hammer2_synchro.c
 */
void hammer2_primary_sync_thread(void *arg);

/*
 * XOP backends in hammer2_xops.c, primarily for VNOPS.  Other XOP backends
 * may be integrated into other source files.
 */
void hammer2_xop_ipcluster(hammer2_xop_t *xop, int clidx);
void hammer2_xop_readdir(hammer2_xop_t *xop, int clidx);
void hammer2_xop_nresolve(hammer2_xop_t *xop, int clidx);
void hammer2_xop_unlink(hammer2_xop_t *xop, int clidx);
void hammer2_xop_nrename(hammer2_xop_t *xop, int clidx);
void hammer2_xop_nlink(hammer2_xop_t *xop, int clidx);
void hammer2_xop_scanlhc(hammer2_xop_t *xop, int clidx);
void hammer2_xop_scanall(hammer2_xop_t *xop, int clidx);
void hammer2_xop_lookup(hammer2_xop_t *xop, int clidx);
void hammer2_inode_xop_create(hammer2_xop_t *xop, int clidx);
void hammer2_inode_xop_destroy(hammer2_xop_t *xop, int clidx);
void hammer2_inode_xop_chain_sync(hammer2_xop_t *xop, int clidx);
void hammer2_inode_xop_unlinkall(hammer2_xop_t *xop, int clidx);
void hammer2_inode_xop_connect(hammer2_xop_t *xop, int clidx);
void hammer2_inode_xop_flush(hammer2_xop_t *xop, int clidx);

/*
 * hammer2_msgops.c
 */
int hammer2_msg_dbg_rcvmsg(kdmsg_msg_t *msg);
int hammer2_msg_adhoc_input(kdmsg_msg_t *msg);

/*
 * hammer2_vfsops.c
 */
void hammer2_volconf_update(hammer2_dev_t *hmp, int index);
void hammer2_dump_chain(hammer2_chain_t *chain, int tab, int *countp, char pfx);
int hammer2_vfs_sync(struct mount *mp, int waitflags);
hammer2_pfs_t *hammer2_pfsalloc(hammer2_chain_t *chain,
                                const hammer2_inode_data_t *ripdata,
                                hammer2_tid_t modify_tid);

void hammer2_lwinprog_ref(hammer2_pfs_t *pmp);
void hammer2_lwinprog_drop(hammer2_pfs_t *pmp);
void hammer2_lwinprog_wait(hammer2_pfs_t *pmp, int pipe);

/*
 * hammer2_freemap.c
 */
int hammer2_freemap_alloc(hammer2_chain_t *chain, size_t bytes);
void hammer2_freemap_adjust(hammer2_dev_t *hmp,
                                hammer2_blockref_t *bref, int how);

/*
 * hammer2_cluster.c
 */
uint8_t hammer2_cluster_type(hammer2_cluster_t *cluster);
const hammer2_media_data_t *hammer2_cluster_rdata(hammer2_cluster_t *cluster);
hammer2_media_data_t *hammer2_cluster_wdata(hammer2_cluster_t *cluster);
hammer2_cluster_t *hammer2_cluster_from_chain(hammer2_chain_t *chain);
void hammer2_cluster_bref(hammer2_cluster_t *cluster, hammer2_blockref_t *bref);
hammer2_cluster_t *hammer2_cluster_alloc(hammer2_pfs_t *pmp,
                                hammer2_blockref_t *bref);
void hammer2_cluster_ref(hammer2_cluster_t *cluster);
void hammer2_cluster_drop(hammer2_cluster_t *cluster);
void hammer2_cluster_lock(hammer2_cluster_t *cluster, int how);
int hammer2_cluster_check(hammer2_cluster_t *cluster, hammer2_key_t lokey,
                        int flags);
void hammer2_cluster_resolve(hammer2_cluster_t *cluster);
void hammer2_cluster_forcegood(hammer2_cluster_t *cluster);
hammer2_cluster_t *hammer2_cluster_copy(hammer2_cluster_t *ocluster);
void hammer2_cluster_unlock(hammer2_cluster_t *cluster);

int hammer2_bulkfree_pass(hammer2_dev_t *hmp,
                        struct hammer2_ioc_bulkfree *bfi);

/*
 * hammer2_iocom.c
 */
void hammer2_iocom_init(hammer2_dev_t *hmp);
void hammer2_iocom_uninit(hammer2_dev_t *hmp);
void hammer2_cluster_reconnect(hammer2_dev_t *hmp, struct file *fp);

/*
 * hammer2_strategy.c
 */
int hammer2_vop_strategy(struct vop_strategy_args *ap);
int hammer2_vop_bmap(struct vop_bmap_args *ap);
void hammer2_write_thread(void *arg);
void hammer2_bioq_sync(hammer2_pfs_t *pmp);
void hammer2_dedup_clear(hammer2_dev_t *hmp);

#endif /* !_KERNEL */
#endif /* !_VFS_HAMMER2_HAMMER2_H_ */