HAMMER 59B/Many: Stabilization pass - fixes for large file issues

[dragonfly.git] / sys / vfs / hammer / hammer_vfsops.c

/*
 * 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_vfsops.c,v 1.55 2008/06/27 20:56:59 dillon Exp $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/malloc.h>
#include <sys/nlookup.h>
#include <sys/fcntl.h>
#include <sys/sysctl.h>
#include <sys/buf.h>
#include <sys/buf2.h>
#include "hammer.h"

int hammer_debug_io;
int hammer_debug_general;
int hammer_debug_debug;
int hammer_debug_inode;
int hammer_debug_locks;
int hammer_debug_btree;
int hammer_debug_tid;
int hammer_debug_recover;               /* -1 will disable, +1 will force */
int hammer_debug_recover_faults;
int hammer_debug_cluster_enable = 1;    /* enable read clustering by default */
int hammer_count_inodes;
int hammer_count_iqueued;
int hammer_count_reclaiming;
int hammer_count_records;
int hammer_count_record_datas;
int hammer_count_volumes;
int hammer_count_buffers;
int hammer_count_nodes;
int64_t hammer_stats_btree_lookups;
int64_t hammer_stats_btree_searches;
int64_t hammer_stats_btree_inserts;
int64_t hammer_stats_btree_deletes;
int64_t hammer_stats_btree_elements;
int64_t hammer_stats_btree_splits;
int64_t hammer_stats_btree_iterations;
int64_t hammer_stats_record_iterations;
int hammer_count_dirtybufs;             /* global */
int hammer_count_refedbufs;             /* global */
int hammer_count_reservations;
int hammer_count_io_running_read;
int hammer_count_io_running_write;
int hammer_count_io_locked;
int hammer_limit_dirtybufs;             /* per-mount */
int hammer_limit_recs;                  /* as a whole XXX */
int hammer_limit_iqueued;               /* per-mount */
int hammer_bio_count;
int hammer_verify_zone;
int hammer_write_mode;
int64_t hammer_contention_count;
int64_t hammer_zone_limit;

SYSCTL_NODE(_vfs, OID_AUTO, hammer, CTLFLAG_RW, 0, "HAMMER filesystem");
SYSCTL_INT(_vfs_hammer, OID_AUTO, debug_general, CTLFLAG_RW,
           &hammer_debug_general, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, debug_io, CTLFLAG_RW,
           &hammer_debug_io, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, debug_debug, CTLFLAG_RW,
           &hammer_debug_debug, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, debug_inode, CTLFLAG_RW,
           &hammer_debug_inode, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, debug_locks, CTLFLAG_RW,
           &hammer_debug_locks, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, debug_btree, CTLFLAG_RW,
           &hammer_debug_btree, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, debug_tid, CTLFLAG_RW,
           &hammer_debug_tid, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, debug_recover, CTLFLAG_RW,
           &hammer_debug_recover, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, debug_recover_faults, CTLFLAG_RW,
           &hammer_debug_recover_faults, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, debug_cluster_enable, CTLFLAG_RW,
           &hammer_debug_cluster_enable, 0, "");

SYSCTL_INT(_vfs_hammer, OID_AUTO, limit_dirtybufs, CTLFLAG_RW,
           &hammer_limit_dirtybufs, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, limit_recs, CTLFLAG_RW,
           &hammer_limit_recs, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, limit_iqueued, CTLFLAG_RW,
           &hammer_limit_iqueued, 0, "");

SYSCTL_INT(_vfs_hammer, OID_AUTO, count_inodes, CTLFLAG_RD,
           &hammer_count_inodes, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, count_iqueued, CTLFLAG_RD,
           &hammer_count_iqueued, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, count_reclaiming, CTLFLAG_RD,
           &hammer_count_reclaiming, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, count_records, CTLFLAG_RD,
           &hammer_count_records, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, count_record_datas, CTLFLAG_RD,
           &hammer_count_record_datas, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, count_volumes, CTLFLAG_RD,
           &hammer_count_volumes, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, count_buffers, CTLFLAG_RD,
           &hammer_count_buffers, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, count_nodes, CTLFLAG_RD,
           &hammer_count_nodes, 0, "");
SYSCTL_QUAD(_vfs_hammer, OID_AUTO, stats_btree_searches, CTLFLAG_RD,
           &hammer_stats_btree_searches, 0, "");
SYSCTL_QUAD(_vfs_hammer, OID_AUTO, stats_btree_lookups, CTLFLAG_RD,
           &hammer_stats_btree_lookups, 0, "");
SYSCTL_QUAD(_vfs_hammer, OID_AUTO, stats_btree_inserts, CTLFLAG_RD,
           &hammer_stats_btree_inserts, 0, "");
SYSCTL_QUAD(_vfs_hammer, OID_AUTO, stats_btree_deletes, CTLFLAG_RD,
           &hammer_stats_btree_deletes, 0, "");
SYSCTL_QUAD(_vfs_hammer, OID_AUTO, stats_btree_elements, CTLFLAG_RD,
           &hammer_stats_btree_elements, 0, "");
SYSCTL_QUAD(_vfs_hammer, OID_AUTO, stats_btree_splits, CTLFLAG_RD,
           &hammer_stats_btree_splits, 0, "");
SYSCTL_QUAD(_vfs_hammer, OID_AUTO, stats_btree_iterations, CTLFLAG_RD,
           &hammer_stats_btree_iterations, 0, "");
SYSCTL_QUAD(_vfs_hammer, OID_AUTO, stats_record_iterations, CTLFLAG_RD,
           &hammer_stats_record_iterations, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, count_dirtybufs, CTLFLAG_RD,
           &hammer_count_dirtybufs, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, count_refedbufs, CTLFLAG_RD,
           &hammer_count_refedbufs, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, count_reservations, CTLFLAG_RD,
           &hammer_count_reservations, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, count_io_running_read, CTLFLAG_RD,
           &hammer_count_io_running_read, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, count_io_locked, CTLFLAG_RD,
           &hammer_count_io_locked, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, count_io_running_write, CTLFLAG_RD,
           &hammer_count_io_running_write, 0, "");
SYSCTL_QUAD(_vfs_hammer, OID_AUTO, zone_limit, CTLFLAG_RW,
           &hammer_zone_limit, 0, "");
SYSCTL_QUAD(_vfs_hammer, OID_AUTO, contention_count, CTLFLAG_RW,
           &hammer_contention_count, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, verify_zone, CTLFLAG_RW,
           &hammer_verify_zone, 0, "");
SYSCTL_INT(_vfs_hammer, OID_AUTO, write_mode, CTLFLAG_RW,
           &hammer_write_mode, 0, "");

KTR_INFO_MASTER(hammer);

/*
 * VFS ABI
 */
static void     hammer_free_hmp(struct mount *mp);

static int      hammer_vfs_mount(struct mount *mp, char *path, caddr_t data,
                                struct ucred *cred);
static int      hammer_vfs_unmount(struct mount *mp, int mntflags);
static int      hammer_vfs_root(struct mount *mp, struct vnode **vpp);
static int      hammer_vfs_statfs(struct mount *mp, struct statfs *sbp,
                                struct ucred *cred);
static int      hammer_vfs_statvfs(struct mount *mp, struct statvfs *sbp,
                                struct ucred *cred);
static int      hammer_vfs_sync(struct mount *mp, int waitfor);
static int      hammer_vfs_vget(struct mount *mp, ino_t ino,
                                struct vnode **vpp);
static int      hammer_vfs_init(struct vfsconf *conf);
static int      hammer_vfs_fhtovp(struct mount *mp, struct fid *fhp,
                                struct vnode **vpp);
static int      hammer_vfs_vptofh(struct vnode *vp, struct fid *fhp);
static int      hammer_vfs_checkexp(struct mount *mp, struct sockaddr *nam,
                                int *exflagsp, struct ucred **credanonp);


static struct vfsops hammer_vfsops = {
        .vfs_mount      = hammer_vfs_mount,
        .vfs_unmount    = hammer_vfs_unmount,
        .vfs_root       = hammer_vfs_root,
        .vfs_statfs     = hammer_vfs_statfs,
        .vfs_statvfs    = hammer_vfs_statvfs,
        .vfs_sync       = hammer_vfs_sync,
        .vfs_vget       = hammer_vfs_vget,
        .vfs_init       = hammer_vfs_init,
        .vfs_vptofh     = hammer_vfs_vptofh,
        .vfs_fhtovp     = hammer_vfs_fhtovp,
        .vfs_checkexp   = hammer_vfs_checkexp
};

MALLOC_DEFINE(M_HAMMER, "hammer-mount", "hammer mount");

VFS_SET(hammer_vfsops, hammer, 0);
MODULE_VERSION(hammer, 1);

static int
hammer_vfs_init(struct vfsconf *conf)
{
        if (hammer_limit_recs == 0)             /* XXX TODO */
                hammer_limit_recs = nbuf * 25;
        if (hammer_limit_dirtybufs == 0) {
                hammer_limit_dirtybufs = hidirtybuffers / 2;
                if (hammer_limit_dirtybufs < 100)
                        hammer_limit_dirtybufs = 100;
        }
        if (hammer_limit_iqueued == 0)
                hammer_limit_iqueued = desiredvnodes / 5;
        return(0);
}

static int
hammer_vfs_mount(struct mount *mp, char *mntpt, caddr_t data,
                 struct ucred *cred)
{
        struct hammer_mount_info info;
        hammer_mount_t hmp;
        hammer_volume_t rootvol;
        struct vnode *rootvp;
        const char *upath;      /* volume name in userspace */
        char *path;             /* volume name in system space */
        int error;
        int i;

        if ((error = copyin(data, &info, sizeof(info))) != 0)
                return (error);
        if ((mp->mnt_flag & MNT_UPDATE) == 0) {
                if (info.nvolumes <= 0 || info.nvolumes >= 32768)
                        return (EINVAL);
        }
        if ((info.hflags & HMNT_MASTERID) &&
            (info.masterid < -1 || info.masterid >= HAMMER_MAX_MASTERS)) {
                        return (EINVAL);
        }

        /*
         * Interal mount data structure
         */
        if (mp->mnt_flag & MNT_UPDATE) {
                hmp = (void *)mp->mnt_data;
                KKASSERT(hmp != NULL);
        } else {
                hmp = kmalloc(sizeof(*hmp), M_HAMMER, M_WAITOK | M_ZERO);
                mp->mnt_data = (qaddr_t)hmp;
                hmp->mp = mp;
                hmp->namekey_iterator = mycpu->gd_time_seconds;
                /*TAILQ_INIT(&hmp->recycle_list);*/

                hmp->root_btree_beg.localization = 0x00000000U;
                hmp->root_btree_beg.obj_id = -0x8000000000000000LL;
                hmp->root_btree_beg.key = -0x8000000000000000LL;
                hmp->root_btree_beg.create_tid = 1;
                hmp->root_btree_beg.delete_tid = 1;
                hmp->root_btree_beg.rec_type = 0;
                hmp->root_btree_beg.obj_type = 0;

                hmp->root_btree_end.localization = 0xFFFFFFFFU;
                hmp->root_btree_end.obj_id = 0x7FFFFFFFFFFFFFFFLL;
                hmp->root_btree_end.key = 0x7FFFFFFFFFFFFFFFLL;
                hmp->root_btree_end.create_tid = 0xFFFFFFFFFFFFFFFFULL;
                hmp->root_btree_end.delete_tid = 0;   /* special case */
                hmp->root_btree_end.rec_type = 0xFFFFU;
                hmp->root_btree_end.obj_type = 0;

                hmp->sync_lock.refs = 1;
                hmp->free_lock.refs = 1;
                hmp->undo_lock.refs = 1;
                hmp->blkmap_lock.refs = 1;

                TAILQ_INIT(&hmp->flush_list);
                TAILQ_INIT(&hmp->delay_list);
                TAILQ_INIT(&hmp->objid_cache_list);
                TAILQ_INIT(&hmp->undo_lru_list);
                TAILQ_INIT(&hmp->reclaim_list);
        }
        hmp->hflags &= ~HMNT_USERFLAGS;
        hmp->hflags |= info.hflags & HMNT_USERFLAGS;
        if (info.hflags & HMNT_MASTERID)
                hmp->masterid = info.masterid;
        else
                hmp->masterid = -1;
        if (info.asof) {
                kprintf("ASOF\n");
                mp->mnt_flag |= MNT_RDONLY;
                hmp->asof = info.asof;
        } else {
                hmp->asof = HAMMER_MAX_TID;
        }

        /*
         * Re-open read-write if originally read-only, or vise-versa.
         */
        if (mp->mnt_flag & MNT_UPDATE) {
                error = 0;
                if (hmp->ronly && (mp->mnt_kern_flag & MNTK_WANTRDWR)) {
                        kprintf("HAMMER read-only -> read-write\n");
                        hmp->ronly = 0;
                        RB_SCAN(hammer_vol_rb_tree, &hmp->rb_vols_root, NULL,
                                hammer_adjust_volume_mode, NULL);
                        rootvol = hammer_get_root_volume(hmp, &error);
                        if (rootvol) {
                                hammer_recover_flush_buffers(hmp, rootvol, 1);
                                bcopy(rootvol->ondisk->vol0_blockmap,
                                      hmp->blockmap,
                                      sizeof(hmp->blockmap));
                                hammer_rel_volume(rootvol, 0);
                        }
                        RB_SCAN(hammer_ino_rb_tree, &hmp->rb_inos_root, NULL,
                                hammer_reload_inode, NULL);
                        /* kernel clears MNT_RDONLY */
                } else if (hmp->ronly == 0 && (mp->mnt_flag & MNT_RDONLY)) {
                        kprintf("HAMMER read-write -> read-only\n");
                        hmp->ronly = 1; /* messy */
                        RB_SCAN(hammer_ino_rb_tree, &hmp->rb_inos_root, NULL,
                                hammer_reload_inode, NULL);
                        hmp->ronly = 0;
                        hammer_flusher_sync(hmp);
                        hammer_flusher_sync(hmp);
                        hammer_flusher_sync(hmp);
                        hmp->ronly = 1;
                        RB_SCAN(hammer_vol_rb_tree, &hmp->rb_vols_root, NULL,
                                hammer_adjust_volume_mode, NULL);
                }
                return(error);
        }

        RB_INIT(&hmp->rb_vols_root);
        RB_INIT(&hmp->rb_inos_root);
        RB_INIT(&hmp->rb_nods_root);
        RB_INIT(&hmp->rb_undo_root);
        RB_INIT(&hmp->rb_resv_root);
        RB_INIT(&hmp->rb_bufs_root);

        hmp->ronly = ((mp->mnt_flag & MNT_RDONLY) != 0);

        TAILQ_INIT(&hmp->volu_list);
        TAILQ_INIT(&hmp->undo_list);
        TAILQ_INIT(&hmp->data_list);
        TAILQ_INIT(&hmp->meta_list);
        TAILQ_INIT(&hmp->lose_list);

        /*
         * Load volumes
         */
        path = objcache_get(namei_oc, M_WAITOK);
        hmp->nvolumes = info.nvolumes;
        for (i = 0; i < info.nvolumes; ++i) {
                error = copyin(&info.volumes[i], &upath, sizeof(char *));
                if (error == 0)
                        error = copyinstr(upath, path, MAXPATHLEN, NULL);
                if (error == 0)
                        error = hammer_install_volume(hmp, path);
                if (error)
                        break;
        }
        objcache_put(namei_oc, path);

        /*
         * Make sure we found a root volume
         */
        if (error == 0 && hmp->rootvol == NULL) {
                kprintf("hammer_mount: No root volume found!\n");
                error = EINVAL;
        }
        if (error) {
                hammer_free_hmp(mp);
                return (error);
        }

        /*
         * No errors, setup enough of the mount point so we can lookup the
         * root vnode.
         */
        mp->mnt_iosize_max = MAXPHYS;
        mp->mnt_kern_flag |= MNTK_FSMID;

        /* 
         * note: f_iosize is used by vnode_pager_haspage() when constructing
         * its VOP_BMAP call.
         */
        mp->mnt_stat.f_iosize = HAMMER_BUFSIZE;
        mp->mnt_stat.f_bsize = HAMMER_BUFSIZE;

        mp->mnt_vstat.f_frsize = HAMMER_BUFSIZE;
        mp->mnt_vstat.f_bsize = HAMMER_BUFSIZE;

        mp->mnt_maxsymlinklen = 255;
        mp->mnt_flag |= MNT_LOCAL;

        vfs_add_vnodeops(mp, &hammer_vnode_vops, &mp->mnt_vn_norm_ops);
        vfs_add_vnodeops(mp, &hammer_spec_vops, &mp->mnt_vn_spec_ops);
        vfs_add_vnodeops(mp, &hammer_fifo_vops, &mp->mnt_vn_fifo_ops);

        /*
         * The root volume's ondisk pointer is only valid if we hold a
         * reference to it.
         */
        rootvol = hammer_get_root_volume(hmp, &error);
        if (error)
                goto failed;

        /*
         * Perform any necessary UNDO operations.  The recovery code does
         * call hammer_undo_lookup() so we have to pre-cache the blockmap,
         * and then re-copy it again after recovery is complete.
         *
         * If this is a read-only mount the UNDO information is retained
         * in memory in the form of dirty buffer cache buffers, and not
         * written back to the media.
         */
        bcopy(rootvol->ondisk->vol0_blockmap, hmp->blockmap,
              sizeof(hmp->blockmap));

        error = hammer_recover(hmp, rootvol);
        if (error) {
                kprintf("Failed to recover HAMMER filesystem on mount\n");
                goto done;
        }

        /*
         * Finish setup now that we have a good root volume
         */
        ksnprintf(mp->mnt_stat.f_mntfromname,
                  sizeof(mp->mnt_stat.f_mntfromname), "%s",
                  rootvol->ondisk->vol_name);
        mp->mnt_stat.f_fsid.val[0] =
                crc32((char *)&rootvol->ondisk->vol_fsid + 0, 8);
        mp->mnt_stat.f_fsid.val[1] =
                crc32((char *)&rootvol->ondisk->vol_fsid + 8, 8);

        mp->mnt_vstat.f_fsid_uuid = rootvol->ondisk->vol_fsid;
        mp->mnt_vstat.f_fsid = crc32(&mp->mnt_vstat.f_fsid_uuid,
                                     sizeof(mp->mnt_vstat.f_fsid_uuid));

        /*
         * Certain often-modified fields in the root volume are cached in
         * the hammer_mount structure so we do not have to generate lots
         * of little UNDO structures for them.
         *
         * Recopy after recovery.  This also has the side effect of
         * setting our cached undo FIFO's first_offset, which serves to
         * placemark the FIFO start for the NEXT flush cycle while the
         * on-disk first_offset represents the LAST flush cycle.
         */
        hmp->next_tid = rootvol->ondisk->vol0_next_tid;
        bcopy(rootvol->ondisk->vol0_blockmap, hmp->blockmap,
              sizeof(hmp->blockmap));
        hmp->copy_stat_freebigblocks = rootvol->ondisk->vol0_stat_freebigblocks;

        hammer_flusher_create(hmp);

        /*
         * Locate the root directory using the root cluster's B-Tree as a
         * starting point.  The root directory uses an obj_id of 1.
         *
         * FUTURE: Leave the root directory cached referenced but unlocked
         * in hmp->rootvp (need to flush it on unmount).
         */
        error = hammer_vfs_vget(mp, 1, &rootvp);
        if (error)
                goto done;
        vput(rootvp);
        /*vn_unlock(hmp->rootvp);*/

done:
        hammer_rel_volume(rootvol, 0);
failed:
        /*
         * Cleanup and return.
         */
        if (error)
                hammer_free_hmp(mp);
        return (error);
}

static int
hammer_vfs_unmount(struct mount *mp, int mntflags)
{
#if 0
        struct hammer_mount *hmp = (void *)mp->mnt_data;
#endif
        int flags;
        int error;

        /*
         * Clean out the vnodes
         */
        flags = 0;
        if (mntflags & MNT_FORCE)
                flags |= FORCECLOSE;
        if ((error = vflush(mp, 0, flags)) != 0)
                return (error);

        /*
         * Clean up the internal mount structure and related entities.  This
         * may issue I/O.
         */
        hammer_free_hmp(mp);
        return(0);
}

/*
 * Clean up the internal mount structure and disassociate it from the mount.
 * This may issue I/O.
 */
static void
hammer_free_hmp(struct mount *mp)
{
        struct hammer_mount *hmp = (void *)mp->mnt_data;

#if 0
        /*
         * Clean up the root vnode
         */
        if (hmp->rootvp) {
                vrele(hmp->rootvp);
                hmp->rootvp = NULL;
        }
#endif
        hammer_flusher_sync(hmp);
        hammer_flusher_sync(hmp);
        hammer_flusher_destroy(hmp);

        KKASSERT(RB_EMPTY(&hmp->rb_inos_root));

#if 0
        /*
         * Unload & flush inodes
         *
         * XXX illegal to call this from here, it can only be done from
         * the flusher.
         */
        RB_SCAN(hammer_ino_rb_tree, &hmp->rb_inos_root, NULL,
                hammer_unload_inode, (void *)MNT_WAIT);

        /*
         * Unload & flush volumes
         */
#endif
        /*
         * Unload buffers and then volumes
         */
        RB_SCAN(hammer_buf_rb_tree, &hmp->rb_bufs_root, NULL,
                hammer_unload_buffer, NULL);
        RB_SCAN(hammer_vol_rb_tree, &hmp->rb_vols_root, NULL,
                hammer_unload_volume, NULL);

        mp->mnt_data = NULL;
        mp->mnt_flag &= ~MNT_LOCAL;
        hmp->mp = NULL;
        hammer_destroy_objid_cache(hmp);
        kfree(hmp, M_HAMMER);
}

/*
 * Obtain a vnode for the specified inode number.  An exclusively locked
 * vnode is returned.
 */
int
hammer_vfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp)
{
        struct hammer_transaction trans;
        struct hammer_mount *hmp = (void *)mp->mnt_data;
        struct hammer_inode *ip;
        int error;

        hammer_simple_transaction(&trans, hmp);

        /*
         * Lookup the requested HAMMER inode.  The structure must be
         * left unlocked while we manipulate the related vnode to avoid
         * a deadlock.
         */
        ip = hammer_get_inode(&trans, NULL, ino,
                              hmp->asof, HAMMER_DEF_LOCALIZATION, 
                              0, &error);
        if (ip == NULL) {
                *vpp = NULL;
                return(error);
        }
        error = hammer_get_vnode(ip, vpp);
        hammer_rel_inode(ip, 0);
        hammer_done_transaction(&trans);
        return (error);
}

/*
 * Return the root vnode for the filesystem.
 *
 * HAMMER stores the root vnode in the hammer_mount structure so
 * getting it is easy.
 */
static int
hammer_vfs_root(struct mount *mp, struct vnode **vpp)
{
#if 0
        struct hammer_mount *hmp = (void *)mp->mnt_data;
#endif
        int error;

        error = hammer_vfs_vget(mp, 1, vpp);
        return (error);
}

static int
hammer_vfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
{
        struct hammer_mount *hmp = (void *)mp->mnt_data;
        hammer_volume_t volume;
        hammer_volume_ondisk_t ondisk;
        int error;
        int64_t bfree;

        volume = hammer_get_root_volume(hmp, &error);
        if (error)
                return(error);
        ondisk = volume->ondisk;

        /*
         * Basic stats
         */
        mp->mnt_stat.f_files = ondisk->vol0_stat_inodes;
        bfree = ondisk->vol0_stat_freebigblocks * HAMMER_LARGEBLOCK_SIZE;
        hammer_rel_volume(volume, 0);

        mp->mnt_stat.f_bfree = bfree / HAMMER_BUFSIZE;
        mp->mnt_stat.f_bavail = mp->mnt_stat.f_bfree;
        if (mp->mnt_stat.f_files < 0)
                mp->mnt_stat.f_files = 0;

        *sbp = mp->mnt_stat;
        return(0);
}

static int
hammer_vfs_statvfs(struct mount *mp, struct statvfs *sbp, struct ucred *cred)
{
        struct hammer_mount *hmp = (void *)mp->mnt_data;
        hammer_volume_t volume;
        hammer_volume_ondisk_t ondisk;
        int error;
        int64_t bfree;

        volume = hammer_get_root_volume(hmp, &error);
        if (error)
                return(error);
        ondisk = volume->ondisk;

        /*
         * Basic stats
         */
        mp->mnt_vstat.f_files = ondisk->vol0_stat_inodes;
        bfree = ondisk->vol0_stat_freebigblocks * HAMMER_LARGEBLOCK_SIZE;
        hammer_rel_volume(volume, 0);

        mp->mnt_vstat.f_bfree = bfree / HAMMER_BUFSIZE;
        mp->mnt_vstat.f_bavail = mp->mnt_stat.f_bfree;
        if (mp->mnt_vstat.f_files < 0)
                mp->mnt_vstat.f_files = 0;
        *sbp = mp->mnt_vstat;
        return(0);
}

/*
 * Sync the filesystem.  Currently we have to run it twice, the second
 * one will advance the undo start index to the end index, so if a crash
 * occurs no undos will be run on mount.
 *
 * We do not sync the filesystem if we are called from a panic.  If we did
 * we might end up blowing up a sync that was already in progress.
 */
static int
hammer_vfs_sync(struct mount *mp, int waitfor)
{
        struct hammer_mount *hmp = (void *)mp->mnt_data;
        int error;

        if (panicstr == NULL) {
                error = hammer_sync_hmp(hmp, waitfor);
                if (error == 0)
                        error = hammer_sync_hmp(hmp, waitfor);
        } else {
                error = EIO;
        }
        return (error);
}

/*
 * Convert a vnode to a file handle.
 */
static int
hammer_vfs_vptofh(struct vnode *vp, struct fid *fhp)
{
        hammer_inode_t ip;

        KKASSERT(MAXFIDSZ >= 16);
        ip = VTOI(vp);
        fhp->fid_len = offsetof(struct fid, fid_data[16]);
        fhp->fid_reserved = 0;
        bcopy(&ip->obj_id, fhp->fid_data + 0, sizeof(ip->obj_id));
        bcopy(&ip->obj_asof, fhp->fid_data + 8, sizeof(ip->obj_asof));
        return(0);
}


/*
 * Convert a file handle back to a vnode.
 */
static int
hammer_vfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp)
{
        struct hammer_transaction trans;
        struct hammer_inode *ip;
        struct hammer_inode_info info;
        int error;

        bcopy(fhp->fid_data + 0, &info.obj_id, sizeof(info.obj_id));
        bcopy(fhp->fid_data + 8, &info.obj_asof, sizeof(info.obj_asof));

        hammer_simple_transaction(&trans, (void *)mp->mnt_data);

        /*
         * Get/allocate the hammer_inode structure.  The structure must be
         * unlocked while we manipulate the related vnode to avoid a
         * deadlock.
         */
        ip = hammer_get_inode(&trans, NULL, info.obj_id,
                              info.obj_asof, HAMMER_DEF_LOCALIZATION,
                              0, &error);
        if (ip == NULL) {
                *vpp = NULL;
                return(error);
        }
        error = hammer_get_vnode(ip, vpp);
        hammer_rel_inode(ip, 0);
        hammer_done_transaction(&trans);
        return (error);
}

static int
hammer_vfs_checkexp(struct mount *mp, struct sockaddr *nam,
                    int *exflagsp, struct ucred **credanonp)
{
        hammer_mount_t hmp = (void *)mp->mnt_data;
        struct netcred *np;
        int error;

        np = vfs_export_lookup(mp, &hmp->export, nam);
        if (np) {
                *exflagsp = np->netc_exflags;
                *credanonp = &np->netc_anon;
                error = 0;
        } else {
                error = EACCES;
        }
        return (error);

}

int
hammer_vfs_export(struct mount *mp, int op, const struct export_args *export)
{
        hammer_mount_t hmp = (void *)mp->mnt_data;
        int error;

        switch(op) {
        case MOUNTCTL_SET_EXPORT:
                error = vfs_export(mp, &hmp->export, export);
                break;
        default:
                error = EOPNOTSUPP;
                break;
        }
        return(error);
}