[apple/xnu.git] / bsd / hfs / hfs_vfsops.c

/*
 * Copyright (c) 1999-2005 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*
 * Copyright (c) 1991, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
 *
 *      hfs_vfsops.c
 *  derived from        @(#)ufs_vfsops.c        8.8 (Berkeley) 5/20/95
 *
 *      (c) Copyright 1997-2002 Apple Computer, Inc. All rights reserved.
 *
 *      hfs_vfsops.c -- VFS layer for loadable HFS file system.
 *
 */
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kauth.h>

#include <sys/ubc.h>
#include <sys/vnode_internal.h>
#include <sys/mount_internal.h>
#include <sys/sysctl.h>
#include <sys/malloc.h>
#include <sys/stat.h>
#include <sys/quota.h>
#include <sys/disk.h>
#include <sys/paths.h>
#include <sys/utfconv.h>
#include <sys/kdebug.h>

#include <kern/locks.h>

#include <vfs/vfs_journal.h>

#include <miscfs/specfs/specdev.h>
#include <hfs/hfs_mount.h>

#include "hfs.h"
#include "hfs_catalog.h"
#include "hfs_cnode.h"
#include "hfs_dbg.h"
#include "hfs_endian.h"
#include "hfs_hotfiles.h"
#include "hfs_quota.h"

#include "hfscommon/headers/FileMgrInternal.h"
#include "hfscommon/headers/BTreesInternal.h"


#if     HFS_DIAGNOSTIC
int hfs_dbg_all = 0;
int hfs_dbg_err = 0;
#endif


lck_grp_attr_t *  hfs_group_attr;
lck_attr_t *  hfs_lock_attr;
lck_grp_t *  hfs_mutex_group;
lck_grp_t *  hfs_rwlock_group;


extern struct vnodeopv_desc hfs_vnodeop_opv_desc;

extern void hfs_converterinit(void);

extern void inittodr(time_t base);

extern int  hfs_write_access(struct vnode *, kauth_cred_t, struct proc *, Boolean);


static int hfs_changefs(struct mount *mp, struct hfs_mount_args *args);
static int hfs_fhtovp(struct mount *mp, int fhlen, unsigned char *fhp, struct vnode **vpp, vfs_context_t context);
static int hfs_flushfiles(struct mount *, int, struct proc *);
static int hfs_flushMDB(struct hfsmount *hfsmp, int waitfor, int altflush);
static int hfs_getmountpoint(struct vnode *vp, struct hfsmount **hfsmpp);
static int hfs_init(struct vfsconf *vfsp);
static int hfs_mount(struct mount *mp, vnode_t  devvp, user_addr_t data, vfs_context_t context);
static int hfs_mountfs(struct vnode *devvp, struct mount *mp, struct hfs_mount_args *args, vfs_context_t context);
static int hfs_reload(struct mount *mp, kauth_cred_t cred, struct proc *p);
static int hfs_vfs_root(struct mount *mp, struct vnode **vpp, vfs_context_t context);
static int hfs_quotactl(struct mount *, int, uid_t, caddr_t, vfs_context_t context);
static int hfs_start(struct mount *mp, int flags, vfs_context_t context);
static int hfs_statfs(struct mount *mp, register struct vfsstatfs *sbp, vfs_context_t context);
static int hfs_sync(struct mount *mp, int waitfor, vfs_context_t context);
static int hfs_sysctl(int *name, u_int namelen, user_addr_t oldp, size_t *oldlenp, 
                      user_addr_t newp, size_t newlen, vfs_context_t context);
static int hfs_unmount(struct mount *mp, int mntflags, vfs_context_t context);
static int hfs_vfs_vget(struct mount *mp, ino64_t ino, struct vnode **vpp, vfs_context_t context);
static int hfs_vptofh(struct vnode *vp, int *fhlenp, unsigned char *fhp, vfs_context_t context);

static int hfs_reclaimspace(struct hfsmount *hfsmp, u_long startblk);


/*
 * Called by vfs_mountroot when mounting HFS Plus as root.
 */

__private_extern__
int
hfs_mountroot(mount_t mp, vnode_t rvp, vfs_context_t context)
{
        struct hfsmount *hfsmp;
        ExtendedVCB *vcb;
        struct vfsstatfs *vfsp;
        int error;
        
        if ((error = hfs_mountfs(rvp, mp, NULL, context)))
                return (error);

        /* Init hfsmp */
        hfsmp = VFSTOHFS(mp);

        hfsmp->hfs_uid = UNKNOWNUID;
        hfsmp->hfs_gid = UNKNOWNGID;
        hfsmp->hfs_dir_mask = (S_IRWXU | S_IRGRP|S_IXGRP | S_IROTH|S_IXOTH); /* 0755 */
        hfsmp->hfs_file_mask = (S_IRWXU | S_IRGRP|S_IXGRP | S_IROTH|S_IXOTH); /* 0755 */

        /* Establish the free block reserve. */
        vcb = HFSTOVCB(hfsmp);
        vcb->reserveBlocks = ((u_int64_t)vcb->totalBlocks * HFS_MINFREE) / 100;
        vcb->reserveBlocks = MIN(vcb->reserveBlocks, HFS_MAXRESERVE / vcb->blockSize);

        vfsp = vfs_statfs(mp);
        (void)hfs_statfs(mp, vfsp, NULL);

        return (0);
}


/*
 * VFS Operations.
 *
 * mount system call
 */

static int
hfs_mount(struct mount *mp, vnode_t devvp, user_addr_t data, vfs_context_t context)
{
        struct proc *p = vfs_context_proc(context);
        struct hfsmount *hfsmp = NULL;
        struct hfs_mount_args args;
        int retval = E_NONE;
        uint32_t cmdflags;

        if ((retval = copyin(data, (caddr_t)&args, sizeof(args)))) {
                return (retval);
        }
        cmdflags = (uint32_t)vfs_flags(mp) & MNT_CMDFLAGS;
        if (cmdflags & MNT_UPDATE) {
                hfsmp = VFSTOHFS(mp);

                /* Reload incore data after an fsck. */
                if (cmdflags & MNT_RELOAD) {
                        if (vfs_isrdonly(mp))
                                return hfs_reload(mp, vfs_context_ucred(context), p);
                        else
                                return (EINVAL);
                }

                /* Change to a read-only file system. */
                if (((hfsmp->hfs_flags & HFS_READ_ONLY) == 0) &&
                    vfs_isrdonly(mp)) {
                        int flags;

                        /* use VFS_SYNC to push out System (btree) files */
                        retval = VFS_SYNC(mp, MNT_WAIT, context);
                        if (retval && ((cmdflags & MNT_FORCE) == 0))
                                goto out;
                
                        flags = WRITECLOSE;
                        if (cmdflags & MNT_FORCE)
                                flags |= FORCECLOSE;
                                
                        if ((retval = hfs_flushfiles(mp, flags, p)))
                                goto out;
                        hfsmp->hfs_flags |= HFS_READ_ONLY;
                        retval = hfs_flushvolumeheader(hfsmp, MNT_WAIT, 0);

                        /* also get the volume bitmap blocks */
                        if (!retval) {
                                if (vnode_mount(hfsmp->hfs_devvp) == mp) {
                                        retval = hfs_fsync(hfsmp->hfs_devvp, MNT_WAIT, 0, p);
                                } else {
                                        vnode_get(hfsmp->hfs_devvp);
                                        retval = VNOP_FSYNC(hfsmp->hfs_devvp, MNT_WAIT, context);
                                        vnode_put(hfsmp->hfs_devvp);
                                }
                        }
                        if (retval) {
                                hfsmp->hfs_flags &= ~HFS_READ_ONLY;
                                goto out;
                        }
                        if (hfsmp->jnl) {
                            hfs_global_exclusive_lock_acquire(hfsmp);

                            journal_close(hfsmp->jnl);
                            hfsmp->jnl = NULL;

                            // Note: we explicitly don't want to shutdown
                            //       access to the jvp because we may need
                            //       it later if we go back to being read-write.

                            hfs_global_exclusive_lock_release(hfsmp);
                        }
                }

                /* Change to a writable file system. */
                if (vfs_iswriteupgrade(mp)) {
                        retval = hfs_flushvolumeheader(hfsmp, MNT_WAIT, 0);
                        if (retval != E_NONE)
                                goto out;

                        // If the journal was shut-down previously because we were
                        // asked to be read-only, let's start it back up again now
                        
                        if (   (HFSTOVCB(hfsmp)->vcbAtrb & kHFSVolumeJournaledMask)
                            && hfsmp->jnl == NULL
                            && hfsmp->jvp != NULL) {
                            int jflags;

                            if (hfsmp->hfs_flags & HFS_NEED_JNL_RESET) {
                                        jflags = JOURNAL_RESET;
                            } else {
                                        jflags = 0;
                            }
                            
                            hfs_global_exclusive_lock_acquire(hfsmp);

                            hfsmp->jnl = journal_open(hfsmp->jvp,
                                                      (hfsmp->jnl_start * HFSTOVCB(hfsmp)->blockSize) + (off_t)HFSTOVCB(hfsmp)->hfsPlusIOPosOffset,
                                                      hfsmp->jnl_size,
                                                      hfsmp->hfs_devvp,
                                                      hfsmp->hfs_phys_block_size,
                                                      jflags,
                                                      0,
                                                      hfs_sync_metadata, hfsmp->hfs_mp);

                            hfs_global_exclusive_lock_release(hfsmp);

                            if (hfsmp->jnl == NULL) {
                                retval = EINVAL;
                                goto out;
                            } else {
                                hfsmp->hfs_flags &= ~HFS_NEED_JNL_RESET;
                            }

                        }

                        /* Only clear HFS_READ_ONLY after a successfull write */
                        hfsmp->hfs_flags &= ~HFS_READ_ONLY;

                        if (!(hfsmp->hfs_flags & (HFS_READ_ONLY & HFS_STANDARD))) {
                                /* setup private/hidden directory for unlinked files */
                                FindMetaDataDirectory(HFSTOVCB(hfsmp));
                                hfs_remove_orphans(hfsmp);

                                /*
                                 * Allow hot file clustering if conditions allow.
                                 */
                                if (hfsmp->hfs_flags & HFS_METADATA_ZONE) {
                                        (void) hfs_recording_init(hfsmp);
                                }
                        }
                }

                /* Update file system parameters. */
                retval = hfs_changefs(mp, &args);

        } else /* not an update request */ {

                /* Set the mount flag to indicate that we support volfs  */
                vfs_setflags(mp, (uint64_t)((unsigned int)MNT_DOVOLFS));

                retval = hfs_mountfs(devvp, mp, &args, context);
        }
out:
        if (retval == 0) {
                (void)hfs_statfs(mp, vfs_statfs(mp), context);
        }
        return (retval);
}


struct hfs_changefs_cargs {
        struct hfsmount *hfsmp;
        int             namefix;
        int             permfix;
        int             permswitch;
};

static int
hfs_changefs_callback(struct vnode *vp, void *cargs)
{
        ExtendedVCB *vcb;
        struct cnode *cp;
        struct cat_desc cndesc;
        struct cat_attr cnattr;
        struct hfs_changefs_cargs *args;

        args = (struct hfs_changefs_cargs *)cargs;

        cp = VTOC(vp);
        vcb = HFSTOVCB(args->hfsmp);

        if (cat_lookup(args->hfsmp, &cp->c_desc, 0, &cndesc, &cnattr, NULL, NULL)) {
                /*
                 * If we couldn't find this guy skip to the next one
                 */
                if (args->namefix)
                        cache_purge(vp);

                return (VNODE_RETURNED);
        }
        /*
         * Get the real uid/gid and perm mask from disk.
         */
        if (args->permswitch || args->permfix) {
                cp->c_uid = cnattr.ca_uid;
                cp->c_gid = cnattr.ca_gid;
                cp->c_mode = cnattr.ca_mode;
        }
        /*
         * If we're switching name converters then...
         *   Remove the existing entry from the namei cache.
         *   Update name to one based on new encoder.
         */
        if (args->namefix) {
                cache_purge(vp);
                replace_desc(cp, &cndesc);

                if (cndesc.cd_cnid == kHFSRootFolderID) {
                        strncpy(vcb->vcbVN, cp->c_desc.cd_nameptr, NAME_MAX);
                        cp->c_desc.cd_encoding = args->hfsmp->hfs_encoding;
                }
        } else {
                cat_releasedesc(&cndesc);
        }
        return (VNODE_RETURNED);
}

/* Change fs mount parameters */
static int
hfs_changefs(struct mount *mp, struct hfs_mount_args *args)
{
        int retval = 0;
        int namefix, permfix, permswitch;
        struct hfsmount *hfsmp;
        ExtendedVCB *vcb;
        hfs_to_unicode_func_t   get_unicode_func;
        unicode_to_hfs_func_t   get_hfsname_func;
        u_long old_encoding = 0;
        struct hfs_changefs_cargs cargs;
        uint32_t mount_flags;

        hfsmp = VFSTOHFS(mp);
        vcb = HFSTOVCB(hfsmp);
        mount_flags = (unsigned int)vfs_flags(mp);

        permswitch = (((hfsmp->hfs_flags & HFS_UNKNOWN_PERMS) &&
                       ((mount_flags & MNT_UNKNOWNPERMISSIONS) == 0)) ||
                      (((hfsmp->hfs_flags & HFS_UNKNOWN_PERMS) == 0) &&
                       (mount_flags & MNT_UNKNOWNPERMISSIONS)));

        /* The root filesystem must operate with actual permissions: */
        if (permswitch && (mount_flags & MNT_ROOTFS) && (mount_flags & MNT_UNKNOWNPERMISSIONS)) {
                vfs_clearflags(mp, (uint64_t)((unsigned int)MNT_UNKNOWNPERMISSIONS));   /* Just say "No". */
                return EINVAL;
        }
        if (mount_flags & MNT_UNKNOWNPERMISSIONS)
                hfsmp->hfs_flags |= HFS_UNKNOWN_PERMS;
        else
                hfsmp->hfs_flags &= ~HFS_UNKNOWN_PERMS;

        namefix = permfix = 0;

        /* Change the timezone (Note: this affects all hfs volumes and hfs+ volume create dates) */
        if (args->hfs_timezone.tz_minuteswest != VNOVAL) {
                gTimeZone = args->hfs_timezone;
        }

        /* Change the default uid, gid and/or mask */
        if ((args->hfs_uid != (uid_t)VNOVAL) && (hfsmp->hfs_uid != args->hfs_uid)) {
                hfsmp->hfs_uid = args->hfs_uid;
                if (vcb->vcbSigWord == kHFSPlusSigWord)
                        ++permfix;
        }
        if ((args->hfs_gid != (gid_t)VNOVAL) && (hfsmp->hfs_gid != args->hfs_gid)) {
                hfsmp->hfs_gid = args->hfs_gid;
                if (vcb->vcbSigWord == kHFSPlusSigWord)
                        ++permfix;
        }
        if (args->hfs_mask != (mode_t)VNOVAL) {
                if (hfsmp->hfs_dir_mask != (args->hfs_mask & ALLPERMS)) {
                        hfsmp->hfs_dir_mask = args->hfs_mask & ALLPERMS;
                        hfsmp->hfs_file_mask = args->hfs_mask & ALLPERMS;
                        if ((args->flags != VNOVAL) && (args->flags & HFSFSMNT_NOXONFILES))
                                hfsmp->hfs_file_mask = (args->hfs_mask & DEFFILEMODE);
                        if (vcb->vcbSigWord == kHFSPlusSigWord)
                                ++permfix;
                }
        }
        
        /* Change the hfs encoding value (hfs only) */
        if ((vcb->vcbSigWord == kHFSSigWord)    &&
            (args->hfs_encoding != (u_long)VNOVAL)              &&
            (hfsmp->hfs_encoding != args->hfs_encoding)) {

                retval = hfs_getconverter(args->hfs_encoding, &get_unicode_func, &get_hfsname_func);
                if (retval)
                        goto exit;

                /*
                 * Connect the new hfs_get_unicode converter but leave
                 * the old hfs_get_hfsname converter in place so that
                 * we can lookup existing vnodes to get their correctly
                 * encoded names.
                 *
                 * When we're all finished, we can then connect the new
                 * hfs_get_hfsname converter and release our interest
                 * in the old converters.
                 */
                hfsmp->hfs_get_unicode = get_unicode_func;
                old_encoding = hfsmp->hfs_encoding;
                hfsmp->hfs_encoding = args->hfs_encoding;
                ++namefix;
        }

        if (!(namefix || permfix || permswitch))
                goto exit;

        /* XXX 3762912 hack to support HFS filesystem 'owner' */
        if (permfix)
                vfs_setowner(mp,
                    hfsmp->hfs_uid == UNKNOWNUID ? KAUTH_UID_NONE : hfsmp->hfs_uid,
                    hfsmp->hfs_gid == UNKNOWNGID ? KAUTH_GID_NONE : hfsmp->hfs_gid);
        
        /*
         * For each active vnode fix things that changed
         *
         * Note that we can visit a vnode more than once
         * and we can race with fsync.
         *
         * hfs_changefs_callback will be called for each vnode
         * hung off of this mount point
         * the vnode will be
         * properly referenced and unreferenced around the callback
         */
        cargs.hfsmp = hfsmp;
        cargs.namefix = namefix;
        cargs.permfix = permfix;
        cargs.permswitch = permswitch;

        vnode_iterate(mp, 0, hfs_changefs_callback, (void *)&cargs);

        /*
         * If we're switching name converters we can now
         * connect the new hfs_get_hfsname converter and
         * release our interest in the old converters.
         */
        if (namefix) {
                hfsmp->hfs_get_hfsname = get_hfsname_func;
                vcb->volumeNameEncodingHint = args->hfs_encoding;
                (void) hfs_relconverter(old_encoding);
        }
exit:
        return (retval);
}


struct hfs_reload_cargs {
        struct hfsmount *hfsmp;
        kauth_cred_t cred;
        struct proc     *p;
        int             error;
};

static int
hfs_reload_callback(struct vnode *vp, void *cargs)
{
        struct cnode *cp;
        struct hfs_reload_cargs *args;

        args = (struct hfs_reload_cargs *)cargs;
        /*
         * flush all the buffers associated with this node
         */
        (void) buf_invalidateblks(vp, 0, 0, 0);

        cp = VTOC(vp);
        /* 
         * Remove any directory hints
         */
        if (vnode_isdir(vp))
                hfs_reldirhints(cp, 0);

        /*
         * Re-read cnode data for all active vnodes (non-metadata files).
         */
        if (!vnode_issystem(vp) && !VNODE_IS_RSRC(vp)) {
                struct cat_fork *datafork;
                struct cat_desc desc;

                datafork = cp->c_datafork ? &cp->c_datafork->ff_data : NULL;

                /* lookup by fileID since name could have changed */
                if ((args->error = cat_idlookup(args->hfsmp, cp->c_fileid, &desc, &cp->c_attr, datafork)))
                        return (VNODE_RETURNED_DONE);

                /* update cnode's catalog descriptor */
                (void) replace_desc(cp, &desc);
        }
        return (VNODE_RETURNED);
}

/*
 * Reload all incore data for a filesystem (used after running fsck on
 * the root filesystem and finding things to fix). The filesystem must
 * be mounted read-only.
 *
 * Things to do to update the mount:
 *      invalidate all cached meta-data.
 *      invalidate all inactive vnodes.
 *      invalidate all cached file data.
 *      re-read volume header from disk.
 *      re-load meta-file info (extents, file size).
 *      re-load B-tree header data.
 *      re-read cnode data for all active vnodes.
 */
static int
hfs_reload(struct mount *mountp, kauth_cred_t cred, struct proc *p)
{
        register struct vnode *devvp;
        struct buf *bp;
        int sectorsize;
        int error, i;
        struct hfsmount *hfsmp;
        struct HFSPlusVolumeHeader *vhp;
        ExtendedVCB *vcb;
        struct filefork *forkp;
        struct cat_desc cndesc;
        struct hfs_reload_cargs args;

        hfsmp = VFSTOHFS(mountp);
        vcb = HFSTOVCB(hfsmp);

        if (vcb->vcbSigWord == kHFSSigWord)
                return (EINVAL);        /* rooting from HFS is not supported! */

        /*
         * Invalidate all cached meta-data.
         */
        devvp = hfsmp->hfs_devvp;
        if (buf_invalidateblks(devvp, 0, 0, 0))
                panic("hfs_reload: dirty1");

        args.hfsmp = hfsmp;
        args.cred = cred;
        args.p = p;
        args.error = 0;
        /*
         * hfs_reload_callback will be called for each vnode
         * hung off of this mount point that can't be recycled...
         * vnode_iterate will recycle those that it can (the VNODE_RELOAD option)
         * the vnode will be in an 'unbusy' state (VNODE_WAIT) and 
         * properly referenced and unreferenced around the callback
         */
        vnode_iterate(mountp, VNODE_RELOAD | VNODE_WAIT, hfs_reload_callback, (void *)&args);

        if (args.error)
                return (args.error);

        /*
         * Re-read VolumeHeader from disk.
         */
        sectorsize = hfsmp->hfs_phys_block_size;

        error = (int)buf_meta_bread(hfsmp->hfs_devvp,
                        (daddr64_t)((vcb->hfsPlusIOPosOffset / sectorsize) + HFS_PRI_SECTOR(sectorsize)),
                        sectorsize, NOCRED, &bp);
        if (error) {
                if (bp != NULL)
                        buf_brelse(bp);
                return (error);
        }

        vhp = (HFSPlusVolumeHeader *) (buf_dataptr(bp) + HFS_PRI_OFFSET(sectorsize));

        /* Do a quick sanity check */
        if ((SWAP_BE16(vhp->signature) != kHFSPlusSigWord &&
             SWAP_BE16(vhp->signature) != kHFSXSigWord) ||
            (SWAP_BE16(vhp->version) != kHFSPlusVersion &&
             SWAP_BE16(vhp->version) != kHFSXVersion) ||
            SWAP_BE32(vhp->blockSize) != vcb->blockSize) {
                buf_brelse(bp);
                return (EIO);
        }

        vcb->vcbLsMod           = to_bsd_time(SWAP_BE32(vhp->modifyDate));
        vcb->vcbAtrb            = SWAP_BE32 (vhp->attributes);
        vcb->vcbJinfoBlock  = SWAP_BE32(vhp->journalInfoBlock);
        vcb->vcbClpSiz          = SWAP_BE32 (vhp->rsrcClumpSize);
        vcb->vcbNxtCNID         = SWAP_BE32 (vhp->nextCatalogID);
        vcb->vcbVolBkUp         = to_bsd_time(SWAP_BE32(vhp->backupDate));
        vcb->vcbWrCnt           = SWAP_BE32 (vhp->writeCount);
        vcb->vcbFilCnt          = SWAP_BE32 (vhp->fileCount);
        vcb->vcbDirCnt          = SWAP_BE32 (vhp->folderCount);
        vcb->nextAllocation     = SWAP_BE32 (vhp->nextAllocation);
        vcb->totalBlocks        = SWAP_BE32 (vhp->totalBlocks);
        vcb->freeBlocks         = SWAP_BE32 (vhp->freeBlocks);
        vcb->encodingsBitmap    = SWAP_BE64 (vhp->encodingsBitmap);
        bcopy(vhp->finderInfo, vcb->vcbFndrInfo, sizeof(vhp->finderInfo));    
        vcb->localCreateDate    = SWAP_BE32 (vhp->createDate); /* hfs+ create date is in local time */ 

        /*
         * Re-load meta-file vnode data (extent info, file size, etc).
         */
        forkp = VTOF((struct vnode *)vcb->extentsRefNum);
        for (i = 0; i < kHFSPlusExtentDensity; i++) {
                forkp->ff_extents[i].startBlock =
                        SWAP_BE32 (vhp->extentsFile.extents[i].startBlock);
                forkp->ff_extents[i].blockCount =
                        SWAP_BE32 (vhp->extentsFile.extents[i].blockCount);
        }
        forkp->ff_size      = SWAP_BE64 (vhp->extentsFile.logicalSize);
        forkp->ff_blocks    = SWAP_BE32 (vhp->extentsFile.totalBlocks);
        forkp->ff_clumpsize = SWAP_BE32 (vhp->extentsFile.clumpSize);


        forkp = VTOF((struct vnode *)vcb->catalogRefNum);
        for (i = 0; i < kHFSPlusExtentDensity; i++) {
                forkp->ff_extents[i].startBlock =
                        SWAP_BE32 (vhp->catalogFile.extents[i].startBlock);
                forkp->ff_extents[i].blockCount =
                        SWAP_BE32 (vhp->catalogFile.extents[i].blockCount);
        }
        forkp->ff_size      = SWAP_BE64 (vhp->catalogFile.logicalSize);
        forkp->ff_blocks    = SWAP_BE32 (vhp->catalogFile.totalBlocks);
        forkp->ff_clumpsize = SWAP_BE32 (vhp->catalogFile.clumpSize);

        if (hfsmp->hfs_attribute_vp) {
                forkp = VTOF(hfsmp->hfs_attribute_vp);
                for (i = 0; i < kHFSPlusExtentDensity; i++) {
                        forkp->ff_extents[i].startBlock =
                                SWAP_BE32 (vhp->attributesFile.extents[i].startBlock);
                        forkp->ff_extents[i].blockCount =
                                SWAP_BE32 (vhp->attributesFile.extents[i].blockCount);
                }
                forkp->ff_size      = SWAP_BE64 (vhp->attributesFile.logicalSize);
                forkp->ff_blocks    = SWAP_BE32 (vhp->attributesFile.totalBlocks);
                forkp->ff_clumpsize = SWAP_BE32 (vhp->attributesFile.clumpSize);
        }

        forkp = VTOF((struct vnode *)vcb->allocationsRefNum);
        for (i = 0; i < kHFSPlusExtentDensity; i++) {
                forkp->ff_extents[i].startBlock =
                        SWAP_BE32 (vhp->allocationFile.extents[i].startBlock);
                forkp->ff_extents[i].blockCount =
                        SWAP_BE32 (vhp->allocationFile.extents[i].blockCount);
        }
        forkp->ff_size      = SWAP_BE64 (vhp->allocationFile.logicalSize);
        forkp->ff_blocks    = SWAP_BE32 (vhp->allocationFile.totalBlocks);
        forkp->ff_clumpsize = SWAP_BE32 (vhp->allocationFile.clumpSize);

        buf_brelse(bp);
        vhp = NULL;

        /*
         * Re-load B-tree header data
         */
        forkp = VTOF((struct vnode *)vcb->extentsRefNum);
        if ( (error = MacToVFSError( BTReloadData((FCB*)forkp) )) )
                return (error);

        forkp = VTOF((struct vnode *)vcb->catalogRefNum);
        if ( (error = MacToVFSError( BTReloadData((FCB*)forkp) )) )
                return (error);

        if (hfsmp->hfs_attribute_vp) {
                forkp = VTOF(hfsmp->hfs_attribute_vp);
                if ( (error = MacToVFSError( BTReloadData((FCB*)forkp) )) )
                        return (error);
        }

        /* Reload the volume name */
        if ((error = cat_idlookup(hfsmp, kHFSRootFolderID, &cndesc, NULL, NULL)))
                return (error);
        vcb->volumeNameEncodingHint = cndesc.cd_encoding;
        bcopy(cndesc.cd_nameptr, vcb->vcbVN, min(255, cndesc.cd_namelen));
        cat_releasedesc(&cndesc);

        /* Re-establish private/hidden directory for unlinked files */
        FindMetaDataDirectory(vcb);

        /* In case any volume information changed to trigger a notification */
        hfs_generate_volume_notifications(hfsmp);
    
        return (0);
}


/*
 * Common code for mount and mountroot
 */
static int
hfs_mountfs(struct vnode *devvp, struct mount *mp, struct hfs_mount_args *args,
            vfs_context_t context)
{
        struct proc *p = vfs_context_proc(context);
        int retval = E_NONE;
        struct hfsmount *hfsmp;
        struct buf *bp;
        dev_t dev;
        HFSMasterDirectoryBlock *mdbp;
        int ronly;
        int i;
        int mntwrapper;
        kauth_cred_t cred;
        u_int64_t disksize;
        daddr64_t blkcnt;
        u_int32_t blksize;
        u_int32_t minblksize;
        u_int32_t iswritable;
        daddr64_t mdb_offset;

        ronly = vfs_isrdonly(mp);
        dev = vnode_specrdev(devvp);
        cred = p ? vfs_context_ucred(context) : NOCRED;
        mntwrapper = 0;

        bp = NULL;
        hfsmp = NULL;
        mdbp = NULL;
        minblksize = kHFSBlockSize;

        /* Advisory locking should be handled at the VFS layer */
        vfs_setlocklocal(mp);

        /* Get the real physical block size. */
        if (VNOP_IOCTL(devvp, DKIOCGETBLOCKSIZE, (caddr_t)&blksize, 0, context)) {
                retval = ENXIO;
                goto error_exit;
        }
        /* Switch to 512 byte sectors (temporarily) */
        if (blksize > 512) {
                u_int32_t size512 = 512;

                if (VNOP_IOCTL(devvp, DKIOCSETBLOCKSIZE, (caddr_t)&size512, FWRITE, context)) {
                        retval = ENXIO;
                        goto error_exit;
                }
        }
        /* Get the number of 512 byte physical blocks. */
        if (VNOP_IOCTL(devvp, DKIOCGETBLOCKCOUNT, (caddr_t)&blkcnt, 0, context)) {
                retval = ENXIO;
                goto error_exit;
        }
        /* Compute an accurate disk size (i.e. within 512 bytes) */
        disksize = (u_int64_t)blkcnt * (u_int64_t)512;

        /*
         * On Tiger it is not necessary to switch the device 
         * block size to be 4k if there are more than 31-bits
         * worth of blocks but to insure compatibility with
         * pre-Tiger systems we have to do it.
         */
        if (blkcnt > (u_int64_t)0x000000007fffffff) {
                minblksize = blksize = 4096;
        }
        
        /* Now switch to our prefered physical block size. */
        if (blksize > 512) {
                if (VNOP_IOCTL(devvp, DKIOCSETBLOCKSIZE, (caddr_t)&blksize, FWRITE, context)) {
                        retval = ENXIO;
                        goto error_exit;
                }
                /* Get the count of physical blocks. */
                if (VNOP_IOCTL(devvp, DKIOCGETBLOCKCOUNT, (caddr_t)&blkcnt, 0, context)) {
                        retval = ENXIO;
                        goto error_exit;
                }
        }
        /*
         * At this point:
         *   minblksize is the minimum physical block size
         *   blksize has our prefered physical block size
         *   blkcnt has the total number of physical blocks
         */

        mdb_offset = (daddr64_t)HFS_PRI_SECTOR(blksize);
        if ((retval = (int)buf_meta_bread(devvp, mdb_offset, blksize, cred, &bp))) {
                goto error_exit;
        }
        MALLOC(mdbp, HFSMasterDirectoryBlock *, kMDBSize, M_TEMP, M_WAITOK);
        bcopy((char *)buf_dataptr(bp) + HFS_PRI_OFFSET(blksize), mdbp, kMDBSize);
        buf_brelse(bp);
        bp = NULL;

        MALLOC(hfsmp, struct hfsmount *, sizeof(struct hfsmount), M_HFSMNT, M_WAITOK);
        bzero(hfsmp, sizeof(struct hfsmount));
        
        /*
         *  Init the volume information structure
         */
        
        lck_mtx_init(&hfsmp->hfs_mutex, hfs_mutex_group, hfs_lock_attr);
        lck_mtx_init(&hfsmp->hfc_mutex, hfs_mutex_group, hfs_lock_attr);
        lck_rw_init(&hfsmp->hfs_global_lock, hfs_rwlock_group, hfs_lock_attr);
        lck_rw_init(&hfsmp->hfs_insync, hfs_rwlock_group, hfs_lock_attr);

        vfs_setfsprivate(mp, hfsmp);
        hfsmp->hfs_mp = mp;                     /* Make VFSTOHFS work */
        hfsmp->hfs_raw_dev = vnode_specrdev(devvp);
        hfsmp->hfs_devvp = devvp;
        hfsmp->hfs_phys_block_size = blksize;
        hfsmp->hfs_phys_block_count = blkcnt;
        hfsmp->hfs_flags |= HFS_WRITEABLE_MEDIA;
        if (ronly)
                hfsmp->hfs_flags |= HFS_READ_ONLY;
        if (((unsigned int)vfs_flags(mp)) & MNT_UNKNOWNPERMISSIONS)
                hfsmp->hfs_flags |= HFS_UNKNOWN_PERMS;
        for (i = 0; i < MAXQUOTAS; i++)
                dqfileinit(&hfsmp->hfs_qfiles[i]);

        if (args) {
                hfsmp->hfs_uid = (args->hfs_uid == (uid_t)VNOVAL) ? UNKNOWNUID : args->hfs_uid;
                if (hfsmp->hfs_uid == 0xfffffffd) hfsmp->hfs_uid = UNKNOWNUID;
                hfsmp->hfs_gid = (args->hfs_gid == (gid_t)VNOVAL) ? UNKNOWNGID : args->hfs_gid;
                if (hfsmp->hfs_gid == 0xfffffffd) hfsmp->hfs_gid = UNKNOWNGID;
                vfs_setowner(mp, hfsmp->hfs_uid, hfsmp->hfs_gid);                               /* tell the VFS */
                if (args->hfs_mask != (mode_t)VNOVAL) {
                        hfsmp->hfs_dir_mask = args->hfs_mask & ALLPERMS;
                        if (args->flags & HFSFSMNT_NOXONFILES) {
                                hfsmp->hfs_file_mask = (args->hfs_mask & DEFFILEMODE);
                        } else {
                                hfsmp->hfs_file_mask = args->hfs_mask & ALLPERMS;
                        }
                } else {
                        hfsmp->hfs_dir_mask = UNKNOWNPERMISSIONS & ALLPERMS;            /* 0777: rwx---rwx */
                        hfsmp->hfs_file_mask = UNKNOWNPERMISSIONS & DEFFILEMODE;        /* 0666: no --x by default? */
                }
                if ((args->flags != (int)VNOVAL) && (args->flags & HFSFSMNT_WRAPPER))
                        mntwrapper = 1;
        } else {
                /* Even w/o explicit mount arguments, MNT_UNKNOWNPERMISSIONS requires setting up uid, gid, and mask: */
                if (((unsigned int)vfs_flags(mp)) & MNT_UNKNOWNPERMISSIONS) {
                        hfsmp->hfs_uid = UNKNOWNUID;
                        hfsmp->hfs_gid = UNKNOWNGID;
                        vfs_setowner(mp, hfsmp->hfs_uid, hfsmp->hfs_gid);                       /* tell the VFS */
                        hfsmp->hfs_dir_mask = UNKNOWNPERMISSIONS & ALLPERMS;            /* 0777: rwx---rwx */
                        hfsmp->hfs_file_mask = UNKNOWNPERMISSIONS & DEFFILEMODE;        /* 0666: no --x by default? */
                }
        }

        /* Find out if disk media is writable. */
        if (VNOP_IOCTL(devvp, DKIOCISWRITABLE, (caddr_t)&iswritable, 0, context) == 0) {
                if (iswritable)
                        hfsmp->hfs_flags |= HFS_WRITEABLE_MEDIA;
                else
                        hfsmp->hfs_flags &= ~HFS_WRITEABLE_MEDIA;
        }

        // record the current time at which we're mounting this volume
        {
            struct timeval tv;
            microtime(&tv);
            hfsmp->hfs_mount_time = tv.tv_sec;
        }

        /* Mount a standard HFS disk */
        if ((SWAP_BE16(mdbp->drSigWord) == kHFSSigWord) &&
            (mntwrapper || (SWAP_BE16(mdbp->drEmbedSigWord) != kHFSPlusSigWord))) {
                if ((vfs_flags(mp) & MNT_ROOTFS)) {     
                        retval = EINVAL;  /* Cannot root from HFS standard disks */
                        goto error_exit;
                }
                /* HFS disks can only use 512 byte physical blocks */
                if (blksize > kHFSBlockSize) {
                        blksize = kHFSBlockSize;
                        if (VNOP_IOCTL(devvp, DKIOCSETBLOCKSIZE, (caddr_t)&blksize, FWRITE, context)) {
                                retval = ENXIO;
                                goto error_exit;
                        }
                        if (VNOP_IOCTL(devvp, DKIOCGETBLOCKCOUNT, (caddr_t)&blkcnt, 0, context)) {
                                retval = ENXIO;
                                goto error_exit;
                        }
                        hfsmp->hfs_phys_block_size = blksize;
                        hfsmp->hfs_phys_block_count = blkcnt;
                }
                if (args) {
                        hfsmp->hfs_encoding = args->hfs_encoding;
                        HFSTOVCB(hfsmp)->volumeNameEncodingHint = args->hfs_encoding;

                        /* establish the timezone */
                        gTimeZone = args->hfs_timezone;
                }

                retval = hfs_getconverter(hfsmp->hfs_encoding, &hfsmp->hfs_get_unicode,
                                        &hfsmp->hfs_get_hfsname);
                if (retval)
                        goto error_exit;

                retval = hfs_MountHFSVolume(hfsmp, mdbp, p);
                if (retval)
                        (void) hfs_relconverter(hfsmp->hfs_encoding);

        } else /* Mount an HFS Plus disk */ {
                HFSPlusVolumeHeader *vhp;
                off_t embeddedOffset;
                int   jnl_disable = 0;
        
                /* Get the embedded Volume Header */
                if (SWAP_BE16(mdbp->drEmbedSigWord) == kHFSPlusSigWord) {
                        embeddedOffset = SWAP_BE16(mdbp->drAlBlSt) * kHFSBlockSize;
                        embeddedOffset += (u_int64_t)SWAP_BE16(mdbp->drEmbedExtent.startBlock) *
                                          (u_int64_t)SWAP_BE32(mdbp->drAlBlkSiz);

                        /*
                         * If the embedded volume doesn't start on a block
                         * boundary, then switch the device to a 512-byte
                         * block size so everything will line up on a block
                         * boundary.
                         */
                        if ((embeddedOffset % blksize) != 0) {
                                printf("HFS Mount: embedded volume offset not"
                                    " a multiple of physical block size (%d);"
                                    " switching to 512\n", blksize);
                                blksize = 512;
                                if (VNOP_IOCTL(devvp, DKIOCSETBLOCKSIZE,
                                    (caddr_t)&blksize, FWRITE, context)) {
                                        retval = ENXIO;
                                        goto error_exit;
                                }
                                if (VNOP_IOCTL(devvp, DKIOCGETBLOCKCOUNT,
                                    (caddr_t)&blkcnt, 0, context)) {
                                        retval = ENXIO;
                                        goto error_exit;
                                }
                                /* Note: relative block count adjustment */
                                hfsmp->hfs_phys_block_count *=
                                    hfsmp->hfs_phys_block_size / blksize;
                                hfsmp->hfs_phys_block_size = blksize;
                        }

                        disksize = (u_int64_t)SWAP_BE16(mdbp->drEmbedExtent.blockCount) *
                                   (u_int64_t)SWAP_BE32(mdbp->drAlBlkSiz);

                        hfsmp->hfs_phys_block_count = disksize / blksize;
        
                        mdb_offset = (daddr64_t)((embeddedOffset / blksize) + HFS_PRI_SECTOR(blksize));
                        retval = (int)buf_meta_bread(devvp, mdb_offset, blksize, cred, &bp);
                        if (retval)
                                goto error_exit;
                        bcopy((char *)buf_dataptr(bp) + HFS_PRI_OFFSET(blksize), mdbp, 512);
                        buf_brelse(bp);
                        bp = NULL;
                        vhp = (HFSPlusVolumeHeader*) mdbp;

                } else /* pure HFS+ */ {
                        embeddedOffset = 0;
                        vhp = (HFSPlusVolumeHeader*) mdbp;
                }

                // XXXdbg
                //
                hfsmp->jnl = NULL;
                hfsmp->jvp = NULL;
                if (args != NULL && (args->flags & HFSFSMNT_EXTENDED_ARGS) && args->journal_disable) {
                    jnl_disable = 1;
                }
                                
                //
                // We only initialize the journal here if the last person
                // to mount this volume was journaling aware.  Otherwise
                // we delay journal initialization until later at the end
                // of hfs_MountHFSPlusVolume() because the last person who
                // mounted it could have messed things up behind our back
                // (so we need to go find the .journal file, make sure it's
                // the right size, re-sync up if it was moved, etc).
                //
                if (   (SWAP_BE32(vhp->lastMountedVersion) == kHFSJMountVersion)
                        && (SWAP_BE32(vhp->attributes) & kHFSVolumeJournaledMask)
                        && !jnl_disable) {
                        
                        // if we're able to init the journal, mark the mount
                        // point as journaled.
                        //
                        if (hfs_early_journal_init(hfsmp, vhp, args, embeddedOffset, mdb_offset, mdbp, cred) == 0) {
                                vfs_setflags(mp, (uint64_t)((unsigned int)MNT_JOURNALED));
                        } else {
                                // if the journal failed to open, then set the lastMountedVersion
                                // to be "FSK!" which fsck_hfs will see and force the fsck instead
                                // of just bailing out because the volume is journaled.
                                if (!ronly) {
                                    HFSPlusVolumeHeader *jvhp;

                                    hfsmp->hfs_flags |= HFS_NEED_JNL_RESET;
                                    
                                    if (mdb_offset == 0) {
                                        mdb_offset = (daddr64_t)((embeddedOffset / blksize) + HFS_PRI_SECTOR(blksize));
                                    }

                                    bp = NULL;
                                    retval = (int)buf_meta_bread(devvp, mdb_offset, blksize, cred, &bp);
                                    if (retval == 0) {
                                        jvhp = (HFSPlusVolumeHeader *)(buf_dataptr(bp) + HFS_PRI_OFFSET(blksize));
                                            
                                        if (SWAP_BE16(jvhp->signature) == kHFSPlusSigWord || SWAP_BE16(jvhp->signature) == kHFSXSigWord) {
                                                printf ("hfs(1): Journal replay fail.  Writing lastMountVersion as FSK!\n");
                                            jvhp->lastMountedVersion = SWAP_BE32(kFSKMountVersion);
                                            buf_bwrite(bp);
                                        } else {
                                            buf_brelse(bp);
                                        }
                                        bp = NULL;
                                    } else if (bp) {
                                        buf_brelse(bp);
                                        // clear this so the error exit path won't try to use it
                                        bp = NULL;
                                    }
                                }

                                // if this isn't the root device just bail out.
                                // If it is the root device we just continue on
                                // in the hopes that fsck_hfs will be able to
                                // fix any damage that exists on the volume.
                                if ( !(vfs_flags(mp) & MNT_ROOTFS)) {
                                    retval = EINVAL;
                                    goto error_exit;
                                }
                        }
                }
                // XXXdbg
        
                (void) hfs_getconverter(0, &hfsmp->hfs_get_unicode, &hfsmp->hfs_get_hfsname);

                retval = hfs_MountHFSPlusVolume(hfsmp, vhp, embeddedOffset, disksize, p, args, cred);
                /*
                 * If the backend didn't like our physical blocksize
                 * then retry with physical blocksize of 512.
                 */
                if ((retval == ENXIO) && (blksize > 512) && (blksize != minblksize)) {
                        printf("HFS Mount: could not use physical block size "
                                "(%d) switching to 512\n", blksize);
                        blksize = 512;
                        if (VNOP_IOCTL(devvp, DKIOCSETBLOCKSIZE, (caddr_t)&blksize, FWRITE, context)) {
                                retval = ENXIO;
                                goto error_exit;
                        }
                        if (VNOP_IOCTL(devvp, DKIOCGETBLOCKCOUNT, (caddr_t)&blkcnt, 0, context)) {
                                retval = ENXIO;
                                goto error_exit;
                        }
                        devvp->v_specsize = blksize;
                        /* Note: relative block count adjustment (in case this is an embedded volume). */
                        hfsmp->hfs_phys_block_count *= hfsmp->hfs_phys_block_size / blksize;
                        hfsmp->hfs_phys_block_size = blksize;
 
                        if (hfsmp->jnl) {
                            // close and re-open this with the new block size
                            journal_close(hfsmp->jnl);
                            hfsmp->jnl = NULL;
                            if (hfs_early_journal_init(hfsmp, vhp, args, embeddedOffset, mdb_offset, mdbp, cred) == 0) {
                                        vfs_setflags(mp, (uint64_t)((unsigned int)MNT_JOURNALED));
                                } else {
                                        // if the journal failed to open, then set the lastMountedVersion
                                        // to be "FSK!" which fsck_hfs will see and force the fsck instead
                                        // of just bailing out because the volume is journaled.
                                        if (!ronly) {
                                        HFSPlusVolumeHeader *jvhp;

                                        hfsmp->hfs_flags |= HFS_NEED_JNL_RESET;
                                    
                                        if (mdb_offset == 0) {
                                                        mdb_offset = (daddr64_t)((embeddedOffset / blksize) + HFS_PRI_SECTOR(blksize));
                                        }

                                                bp = NULL;
                                        retval = (int)buf_meta_bread(devvp, mdb_offset, blksize, cred, &bp);
                                        if (retval == 0) {
                                                        jvhp = (HFSPlusVolumeHeader *)(buf_dataptr(bp) + HFS_PRI_OFFSET(blksize));
                                            
                                                        if (SWAP_BE16(jvhp->signature) == kHFSPlusSigWord || SWAP_BE16(jvhp->signature) == kHFSXSigWord) {
                                                                printf ("hfs(2): Journal replay fail.  Writing lastMountVersion as FSK!\n");
                                                        jvhp->lastMountedVersion = SWAP_BE32(kFSKMountVersion);
                                                        buf_bwrite(bp);
                                                        } else {
                                                        buf_brelse(bp);
                                                        }
                                                        bp = NULL;
                                        } else if (bp) {
                                                        buf_brelse(bp);
                                                        // clear this so the error exit path won't try to use it
                                                        bp = NULL;
                                        }
                                        }

                                        // if this isn't the root device just bail out.
                                        // If it is the root device we just continue on
                                        // in the hopes that fsck_hfs will be able to
                                        // fix any damage that exists on the volume.
                                        if ( !(vfs_flags(mp) & MNT_ROOTFS)) {
                                        retval = EINVAL;
                                        goto error_exit;
                                        }
                                }
                        }

                        /* Try again with a smaller block size... */
                        retval = hfs_MountHFSPlusVolume(hfsmp, vhp, embeddedOffset, disksize, p, args, cred);
                }
                if (retval)
                        (void) hfs_relconverter(0);
        }

        // save off a snapshot of the mtime from the previous mount
        // (for matador).
        hfsmp->hfs_last_mounted_mtime = hfsmp->hfs_mtime;

        if ( retval ) {
                goto error_exit;
        }

        mp->mnt_vfsstat.f_fsid.val[0] = (long)dev;
        mp->mnt_vfsstat.f_fsid.val[1] = vfs_typenum(mp);
        vfs_setmaxsymlen(mp, 0);
        mp->mnt_vtable->vfc_threadsafe = TRUE;
        mp->mnt_vtable->vfc_vfsflags |= VFC_VFSNATIVEXATTR;

        if (args) {
                /*
                 * Set the free space warning levels for a non-root volume:
                 *
                 * Set the lower freespace limit (the level that will trigger a warning)
                 * to 5% of the volume size or 250MB, whichever is less, and the desired
                 * level (which will cancel the alert request) to 1/2 above that limit.
                 * Start looking for free space to drop below this level and generate a
                 * warning immediately if needed:
                 */
                hfsmp->hfs_freespace_notify_warninglimit =
                        MIN(HFS_LOWDISKTRIGGERLEVEL / HFSTOVCB(hfsmp)->blockSize,
                                (HFSTOVCB(hfsmp)->totalBlocks / 100) * HFS_LOWDISKTRIGGERFRACTION);
                hfsmp->hfs_freespace_notify_desiredlevel =
                        MIN(HFS_LOWDISKSHUTOFFLEVEL / HFSTOVCB(hfsmp)->blockSize,
                                (HFSTOVCB(hfsmp)->totalBlocks / 100) * HFS_LOWDISKSHUTOFFFRACTION);
        } else {
                /*
                 * Set the free space warning levels for the root volume:
                 *
                 * Set the lower freespace limit (the level that will trigger a warning)
                 * to 1% of the volume size or 50MB, whichever is less, and the desired
                 * level (which will cancel the alert request) to 2% or 75MB, whichever is less.
                 */
                hfsmp->hfs_freespace_notify_warninglimit =
                        MIN(HFS_ROOTLOWDISKTRIGGERLEVEL / HFSTOVCB(hfsmp)->blockSize,
                                (HFSTOVCB(hfsmp)->totalBlocks / 100) * HFS_ROOTLOWDISKTRIGGERFRACTION);
                hfsmp->hfs_freespace_notify_desiredlevel =
                        MIN(HFS_ROOTLOWDISKSHUTOFFLEVEL / HFSTOVCB(hfsmp)->blockSize,
                                (HFSTOVCB(hfsmp)->totalBlocks / 100) * HFS_ROOTLOWDISKSHUTOFFFRACTION);
        };
        
        /*
         * Start looking for free space to drop below this level and generate a
         * warning immediately if needed:
         */
        hfsmp->hfs_notification_conditions = 0;
        hfs_generate_volume_notifications(hfsmp);
        
        if (ronly == 0) {
                (void) hfs_flushvolumeheader(hfsmp, MNT_WAIT, 0);
        }
        FREE(mdbp, M_TEMP);
        return (0);

error_exit:
        if (bp)
                buf_brelse(bp);
        if (mdbp)
                FREE(mdbp, M_TEMP);

        if (hfsmp && hfsmp->jvp && hfsmp->jvp != hfsmp->hfs_devvp) {
            (void)VNOP_CLOSE(hfsmp->jvp, ronly ? FREAD : FREAD|FWRITE, context);
                hfsmp->jvp = NULL;
        }
        if (hfsmp) {
                FREE(hfsmp, M_HFSMNT);
                vfs_setfsprivate(mp, NULL);
        }
        return (retval);
}


/*
 * Make a filesystem operational.
 * Nothing to do at the moment.
 */
/* ARGSUSED */
static int
hfs_start(__unused struct mount *mp, __unused int flags, __unused vfs_context_t context)
{
        return (0);
}


/*
 * unmount system call
 */
static int
hfs_unmount(struct mount *mp, int mntflags, vfs_context_t context)
{
        struct proc *p = vfs_context_proc(context);
        struct hfsmount *hfsmp = VFSTOHFS(mp);
        int retval = E_NONE;
        int flags;
        int force;
        int started_tr = 0;

        flags = 0;
        force = 0;
        if (mntflags & MNT_FORCE) {
                flags |= FORCECLOSE;
                force = 1;
        }

        if ((retval = hfs_flushfiles(mp, flags, p)) && !force)
                return (retval);

        if (hfsmp->hfs_flags & HFS_METADATA_ZONE)
                (void) hfs_recording_suspend(hfsmp);

        /*
         * Flush out the b-trees, volume bitmap and Volume Header
         */
        if ((hfsmp->hfs_flags & HFS_READ_ONLY) == 0) {
                hfs_start_transaction(hfsmp);
                started_tr = 1;

                if (hfsmp->hfs_attribute_vp) {
                        (void) hfs_lock(VTOC(hfsmp->hfs_attribute_vp), HFS_EXCLUSIVE_LOCK);
                        retval = hfs_fsync(hfsmp->hfs_attribute_vp, MNT_WAIT, 0, p);
                        hfs_unlock(VTOC(hfsmp->hfs_attribute_vp));
                        if (retval && !force)
                                goto err_exit;
                }

                (void) hfs_lock(VTOC(hfsmp->hfs_catalog_vp), HFS_EXCLUSIVE_LOCK);
                retval = hfs_fsync(hfsmp->hfs_catalog_vp, MNT_WAIT, 0, p);
                hfs_unlock(VTOC(hfsmp->hfs_catalog_vp));
                if (retval && !force)
                        goto err_exit;
                
                (void) hfs_lock(VTOC(hfsmp->hfs_extents_vp), HFS_EXCLUSIVE_LOCK);
                retval = hfs_fsync(hfsmp->hfs_extents_vp, MNT_WAIT, 0, p);
                hfs_unlock(VTOC(hfsmp->hfs_extents_vp));
                if (retval && !force)
                        goto err_exit;
                        
                if (hfsmp->hfs_allocation_vp) {
                        (void) hfs_lock(VTOC(hfsmp->hfs_allocation_vp), HFS_EXCLUSIVE_LOCK);
                        retval = hfs_fsync(hfsmp->hfs_allocation_vp, MNT_WAIT, 0, p);
                        hfs_unlock(VTOC(hfsmp->hfs_allocation_vp));
                        if (retval && !force)
                                goto err_exit;
                }

                if (hfsmp->hfc_filevp && vnode_issystem(hfsmp->hfc_filevp)) {
                        retval = hfs_fsync(hfsmp->hfc_filevp, MNT_WAIT, 0, p);
                        if (retval && !force)
                                goto err_exit;
                }
#if 0           
                /* See if this volume is damaged, is so do not unmount cleanly */
                if (HFSTOVCB(hfsmp)->vcbFlags & kHFS_DamagedVolume) {
                        HFSTOVCB(hfsmp)->vcbAtrb &= ~kHFSVolumeUnmountedMask;
                } else {
                        HFSTOVCB(hfsmp)->vcbAtrb |= kHFSVolumeUnmountedMask;
                }
#else
                HFSTOVCB(hfsmp)->vcbAtrb |= kHFSVolumeUnmountedMask;
#endif
                retval = hfs_flushvolumeheader(hfsmp, MNT_WAIT, 0);
                if (retval) {
                        HFSTOVCB(hfsmp)->vcbAtrb &= ~kHFSVolumeUnmountedMask;
                        if (!force)
                                goto err_exit;  /* could not flush everything */
                }

                hfs_end_transaction(hfsmp);
                started_tr = 0;
        }

        if (hfsmp->jnl) {
                journal_flush(hfsmp->jnl);
        }
        
        /*
         *      Invalidate our caches and release metadata vnodes
         */
        (void) hfsUnmount(hfsmp, p);

        /*
         * Last chance to dump unreferenced system files.
         */
        (void) vflush(mp, NULLVP, FORCECLOSE);

        if (HFSTOVCB(hfsmp)->vcbSigWord == kHFSSigWord)
                (void) hfs_relconverter(hfsmp->hfs_encoding);

        // XXXdbg
        if (hfsmp->jnl) {
            journal_close(hfsmp->jnl);
            hfsmp->jnl = NULL;
        }

        VNOP_FSYNC(hfsmp->hfs_devvp, MNT_WAIT, context);

        if (hfsmp->jvp && hfsmp->jvp != hfsmp->hfs_devvp) {
            retval = VNOP_CLOSE(hfsmp->jvp,
                               hfsmp->hfs_flags & HFS_READ_ONLY ? FREAD : FREAD|FWRITE,
                               context);
            vnode_put(hfsmp->jvp);
            hfsmp->jvp = NULL;
        }
        // XXXdbg

#ifdef HFS_SPARSE_DEV
        /* Drop our reference on the backing fs (if any). */
        if ((hfsmp->hfs_flags & HFS_HAS_SPARSE_DEVICE) && hfsmp->hfs_backingfs_rootvp) {
                struct vnode * tmpvp;

                hfsmp->hfs_flags &= ~HFS_HAS_SPARSE_DEVICE;
                tmpvp = hfsmp->hfs_backingfs_rootvp;
                hfsmp->hfs_backingfs_rootvp = NULLVP;
                vnode_rele(tmpvp);
        }
#endif /* HFS_SPARSE_DEV */
        lck_mtx_destroy(&hfsmp->hfc_mutex, hfs_mutex_group);
        FREE(hfsmp, M_HFSMNT);

        return (0);

  err_exit:
        if (started_tr) {
                hfs_end_transaction(hfsmp);
        }
        return retval;
}


/*
 * Return the root of a filesystem.
 */
static int
hfs_vfs_root(struct mount *mp, struct vnode **vpp, __unused vfs_context_t context)
{
        return hfs_vget(VFSTOHFS(mp), (cnid_t)kHFSRootFolderID, vpp, 1);
}


/*
 * Do operations associated with quotas
 */
static int
hfs_quotactl(struct mount *mp, int cmds, uid_t uid, caddr_t datap, vfs_context_t context)
{
        struct proc *p = vfs_context_proc(context);
        int cmd, type, error;

#if !QUOTA
        return (ENOTSUP);
#else
        if (uid == -1)
                uid = vfs_context_ucred(context)->cr_ruid;
        cmd = cmds >> SUBCMDSHIFT;

        switch (cmd) {
        case Q_SYNC:
        case Q_QUOTASTAT:
                break;
        case Q_GETQUOTA:
                if (uid == vfs_context_ucred(context)->cr_ruid)
                        break;
                /* fall through */
        default:
                if ( (error = vfs_context_suser(context)) )
                        return (error);
        }

        type = cmds & SUBCMDMASK;
        if ((u_int)type >= MAXQUOTAS)
                return (EINVAL);
        if (vfs_busy(mp, LK_NOWAIT))
                return (0);

        switch (cmd) {

        case Q_QUOTAON:
                error = hfs_quotaon(p, mp, type, datap);
                break;

        case Q_QUOTAOFF:
                error = hfs_quotaoff(p, mp, type);
                break;

        case Q_SETQUOTA:
                error = hfs_setquota(mp, uid, type, datap);
                break;

        case Q_SETUSE:
                error = hfs_setuse(mp, uid, type, datap);
                break;

        case Q_GETQUOTA:
                error = hfs_getquota(mp, uid, type, datap);
                break;

        case Q_SYNC:
                error = hfs_qsync(mp);
                break;

        case Q_QUOTASTAT:
                error = hfs_quotastat(mp, type, datap);
                break;

        default:
                error = EINVAL;
                break;
        }
        vfs_unbusy(mp);

        return (error);
#endif /* QUOTA */
}

/* Subtype is composite of bits */
#define HFS_SUBTYPE_JOURNALED      0x01
#define HFS_SUBTYPE_CASESENSITIVE  0x02
/* bits 2 - 6 reserved */
#define HFS_SUBTYPE_STANDARDHFS    0x80

/*
 * Get file system statistics.
 */
static int
hfs_statfs(struct mount *mp, register struct vfsstatfs *sbp, __unused vfs_context_t context)
{
        ExtendedVCB *vcb = VFSTOVCB(mp);
        struct hfsmount *hfsmp = VFSTOHFS(mp);
        u_long freeCNIDs;
        uint16_t subtype = 0;

        freeCNIDs = (u_long)0xFFFFFFFF - (u_long)vcb->vcbNxtCNID;

        sbp->f_bsize = (uint32_t)vcb->blockSize;
        sbp->f_iosize = (size_t)(MAX_UPL_TRANSFER * PAGE_SIZE);
        sbp->f_blocks = (uint64_t)((unsigned long)vcb->totalBlocks);
        sbp->f_bfree = (uint64_t)((unsigned long )hfs_freeblks(hfsmp, 0));
        sbp->f_bavail = (uint64_t)((unsigned long )hfs_freeblks(hfsmp, 1));
        sbp->f_files = (uint64_t)((unsigned long )(vcb->totalBlocks - 2));  /* max files is constrained by total blocks */
        sbp->f_ffree = (uint64_t)((unsigned long )(MIN(freeCNIDs, sbp->f_bavail)));

        /*
         * Subtypes (flavors) for HFS
         *   0:   Mac OS Extended
         *   1:   Mac OS Extended (Journaled) 
         *   2:   Mac OS Extended (Case Sensitive) 
         *   3:   Mac OS Extended (Case Sensitive, Journaled) 
         *   4 - 127:   Reserved
         * 128:   Mac OS Standard
         * 
         */
        if (hfsmp->hfs_flags & HFS_STANDARD) {
                subtype = HFS_SUBTYPE_STANDARDHFS;
        } else /* HFS Plus */ {
                if (hfsmp->jnl)
                        subtype |= HFS_SUBTYPE_JOURNALED;
                if (hfsmp->hfs_flags & HFS_CASE_SENSITIVE)
                        subtype |= HFS_SUBTYPE_CASESENSITIVE;
        }
        sbp->f_fssubtype = subtype;

        return (0);
}


//
// XXXdbg -- this is a callback to be used by the journal to
//           get meta data blocks flushed out to disk.
//
// XXXdbg -- be smarter and don't flush *every* block on each
//           call.  try to only flush some so we don't wind up
//           being too synchronous.
//
__private_extern__
void
hfs_sync_metadata(void *arg)
{
        struct mount *mp = (struct mount *)arg;
        struct hfsmount *hfsmp;
        ExtendedVCB *vcb;
        buf_t   bp;
        int  sectorsize, retval;
        daddr64_t priIDSector;
        hfsmp = VFSTOHFS(mp);
        vcb = HFSTOVCB(hfsmp);

        // now make sure the super block is flushed
        sectorsize = hfsmp->hfs_phys_block_size;
        priIDSector = (daddr64_t)((vcb->hfsPlusIOPosOffset / sectorsize) +
                                  HFS_PRI_SECTOR(sectorsize));
        retval = (int)buf_meta_bread(hfsmp->hfs_devvp, priIDSector, sectorsize, NOCRED, &bp);
        if (retval != 0) {
                panic("hfs: sync_metadata: can't read super-block?! (retval 0x%x, priIDSector)\n",
                          retval, priIDSector);
        }

        if (retval == 0 && ((buf_flags(bp) & (B_DELWRI | B_LOCKED)) == B_DELWRI)) {
            buf_bwrite(bp);
        } else if (bp) {
            buf_brelse(bp);
        }

        // the alternate super block...
        // XXXdbg - we probably don't need to do this each and every time.
        //          hfs_btreeio.c:FlushAlternate() should flag when it was
        //          written...
        if (hfsmp->hfs_alt_id_sector) {
                retval = (int)buf_meta_bread(hfsmp->hfs_devvp, hfsmp->hfs_alt_id_sector, sectorsize, NOCRED, &bp);
                if (retval == 0 && ((buf_flags(bp) & (B_DELWRI | B_LOCKED)) == B_DELWRI)) {
                    buf_bwrite(bp);
                } else if (bp) {
                    buf_brelse(bp);
                }
        }
}


struct hfs_sync_cargs {
        kauth_cred_t cred;
        struct proc  *p;
        int    waitfor;
        int    error;
};


static int
hfs_sync_callback(struct vnode *vp, void *cargs)
{
        struct cnode *cp;
        struct hfs_sync_cargs *args;
        int error;

        args = (struct hfs_sync_cargs *)cargs;

        if (hfs_lock(VTOC(vp), HFS_EXCLUSIVE_LOCK) != 0) {
                return (VNODE_RETURNED);
        }
        cp = VTOC(vp);

        if ((cp->c_flag & C_MODIFIED) ||
            (cp->c_touch_acctime | cp->c_touch_chgtime | cp->c_touch_modtime) ||
            vnode_hasdirtyblks(vp)) {
                error = hfs_fsync(vp, args->waitfor, 0, args->p);

                if (error)
                        args->error = error;
        }
        hfs_unlock(cp);
        return (VNODE_RETURNED);
}



/*
 * Go through the disk queues to initiate sandbagged IO;
 * go through the inodes to write those that have been modified;
 * initiate the writing of the super block if it has been modified.
 *
 * Note: we are always called with the filesystem marked `MPBUSY'.
 */
static int
hfs_sync(struct mount *mp, int waitfor, vfs_context_t context)
{
        struct proc *p = vfs_context_proc(context);
        struct cnode *cp;
        struct hfsmount *hfsmp;
        ExtendedVCB *vcb;
        struct vnode *meta_vp[4];
        int i;
        int error, allerror = 0;
        struct hfs_sync_cargs args;

        /*
         * During MNT_UPDATE hfs_changefs might be manipulating
         * vnodes so back off
         */
        if (((uint32_t)vfs_flags(mp)) & MNT_UPDATE)     /* XXX MNT_UPDATE may not be visible here */
                return (0);

        hfsmp = VFSTOHFS(mp);
        if (hfsmp->hfs_flags & HFS_READ_ONLY)
                return (EROFS);

        /* skip over frozen volumes */
        if (!lck_rw_try_lock_shared(&hfsmp->hfs_insync))
                return 0;

        args.cred = vfs_context_proc(context);
        args.waitfor = waitfor;
        args.p = p;
        args.error = 0;
        /*
         * hfs_sync_callback will be called for each vnode
         * hung off of this mount point... the vnode will be
         * properly referenced and unreferenced around the callback
         */
        vnode_iterate(mp, 0, hfs_sync_callback, (void *)&args);

        if (args.error)
                allerror = args.error;

        vcb = HFSTOVCB(hfsmp);

        meta_vp[0] = vcb->extentsRefNum;
        meta_vp[1] = vcb->catalogRefNum;
        meta_vp[2] = vcb->allocationsRefNum;  /* This is NULL for standard HFS */
        meta_vp[3] = hfsmp->hfs_attribute_vp; /* Optional file */

        /* Now sync our three metadata files */
        for (i = 0; i < 4; ++i) {
                struct vnode *btvp;

                btvp = meta_vp[i];;
                if ((btvp==0) || (vnode_mount(btvp) != mp))
                        continue;

                /* XXX use hfs_systemfile_lock instead ? */
                (void) hfs_lock(VTOC(btvp), HFS_EXCLUSIVE_LOCK);
                cp = VTOC(btvp);

                if (((cp->c_flag &  C_MODIFIED) == 0) &&
                    (cp->c_touch_acctime == 0) &&
                    (cp->c_touch_chgtime == 0) &&
                    (cp->c_touch_modtime == 0) &&
                    vnode_hasdirtyblks(btvp) == 0) {
                        hfs_unlock(VTOC(btvp));
                        continue;
                }
                error = vnode_get(btvp);
                if (error) {
                        hfs_unlock(VTOC(btvp));
                        continue;
                }
                if ((error = hfs_fsync(btvp, waitfor, 0, p)))
                        allerror = error;

                hfs_unlock(cp);
                vnode_put(btvp);
        };

        /*
         * Force stale file system control information to be flushed.
         */
        if (vcb->vcbSigWord == kHFSSigWord) {
                if ((error = VNOP_FSYNC(hfsmp->hfs_devvp, waitfor, context))) {
                        allerror = error;
                }
        }
#if QUOTA
        hfs_qsync(mp);
#endif /* QUOTA */

        hfs_hotfilesync(hfsmp, p);
        /*
         * Write back modified superblock.
         */

        if (IsVCBDirty(vcb)) {
                error = hfs_flushvolumeheader(hfsmp, waitfor, 0);
                if (error)
                        allerror = error;
        }

        if (hfsmp->jnl) {
            journal_flush(hfsmp->jnl);
        }

        lck_rw_unlock_shared(&hfsmp->hfs_insync);       
        return (allerror);
}


/*
 * File handle to vnode
 *
 * Have to be really careful about stale file handles:
 * - check that the cnode id is valid
 * - call hfs_vget() to get the locked cnode
 * - check for an unallocated cnode (i_mode == 0)
 * - check that the given client host has export rights and return
 *   those rights via. exflagsp and credanonp
 */
static int
hfs_fhtovp(struct mount *mp, int fhlen, unsigned char *fhp, struct vnode **vpp, vfs_context_t context)
{
        struct hfsfid *hfsfhp;
        struct vnode *nvp;
        int result;

        *vpp = NULL;
        hfsfhp = (struct hfsfid *)fhp;

        if (fhlen < sizeof(struct hfsfid))
                return (EINVAL);

        result = hfs_vget(VFSTOHFS(mp), hfsfhp->hfsfid_cnid, &nvp, 0);
        if (result) {
                if (result == ENOENT)
                        result = ESTALE;
                return result;
        }
        
        /* The createtime can be changed by hfs_setattr or hfs_setattrlist.
         * For NFS, we are assuming that only if the createtime was moved
         * forward would it mean the fileID got reused in that session by
         * wrapping. We don't have a volume ID or other unique identifier to
         * to use here for a generation ID across reboots, crashes where 
         * metadata noting lastFileID didn't make it to disk but client has
         * it, or volume erasures where fileIDs start over again. Lastly,
         * with HFS allowing "wraps" of fileIDs now, this becomes more
         * error prone. Future, would be change the "wrap bit" to a unique
         * wrap number and use that for generation number. For now do this.
         */  
        if ((hfsfhp->hfsfid_gen < VTOC(nvp)->c_itime)) {
                hfs_unlock(VTOC(nvp));
                vnode_put(nvp);
                return (ESTALE);
        }
        *vpp = nvp;

        hfs_unlock(VTOC(nvp));
        return (0);
}


/*
 * Vnode pointer to File handle
 */
/* ARGSUSED */
static int
hfs_vptofh(struct vnode *vp, int *fhlenp, unsigned char *fhp, vfs_context_t context)
{
        struct cnode *cp;
        struct hfsfid *hfsfhp;

        if (ISHFS(VTOVCB(vp)))
                return (ENOTSUP);       /* hfs standard is not exportable */

        if (*fhlenp < (int)sizeof(struct hfsfid))
                return (EOVERFLOW);

        cp = VTOC(vp);
        hfsfhp = (struct hfsfid *)fhp;
        hfsfhp->hfsfid_cnid = cp->c_fileid;
        hfsfhp->hfsfid_gen = cp->c_itime;
        *fhlenp = sizeof(struct hfsfid);
        
        return (0);
}


/*
 * Initial HFS filesystems, done only once.
 */
static int
hfs_init(__unused struct vfsconf *vfsp)
{
        static int done = 0;

        if (done)
                return (0);
        done = 1;
        hfs_chashinit();
        hfs_converterinit();
#if QUOTA
        dqinit();
#endif /* QUOTA */

        BTReserveSetup();
        
        
        hfs_lock_attr    = lck_attr_alloc_init();
        hfs_group_attr   = lck_grp_attr_alloc_init();
        hfs_mutex_group  = lck_grp_alloc_init("hfs-mutex", hfs_group_attr);
        hfs_rwlock_group = lck_grp_alloc_init("hfs-rwlock", hfs_group_attr);

        /* Turn on lock debugging */
        //lck_attr_setdebug(hfs_lock_attr);


        return (0);
}

static int
hfs_getmountpoint(vp, hfsmpp)
        struct vnode *vp;
        struct hfsmount **hfsmpp;
{
        struct hfsmount * hfsmp;
        char fstypename[MFSNAMELEN];

        if (vp == NULL)
                return (EINVAL);
        
        if (!vnode_isvroot(vp))
                return (EINVAL);

        vnode_vfsname(vp, fstypename);
        if (strcmp(fstypename, "hfs") != 0)
                return (EINVAL);

        hfsmp = VTOHFS(vp);

        if (HFSTOVCB(hfsmp)->vcbSigWord == kHFSSigWord)
                return (EINVAL);

        *hfsmpp = hfsmp;

        return (0);
}

// XXXdbg
#include <sys/filedesc.h>

/*
 * HFS filesystem related variables.
 */
static int
hfs_sysctl(int *name, __unused u_int namelen, user_addr_t oldp, size_t *oldlenp, 
                        user_addr_t newp, size_t newlen, vfs_context_t context)
{
        struct proc *p = vfs_context_proc(context);
        int error;
        struct hfsmount *hfsmp;

        /* all sysctl names at this level are terminal */

        if (name[0] == HFS_ENCODINGBIAS) {
                u_int32_t bias;

                bias = hfs_getencodingbias();
                error = sysctl_int(oldp, oldlenp, newp, newlen, &bias);
                if (error == 0 && newp)
                        hfs_setencodingbias(bias);
                return (error);

        } else if (name[0] == HFS_EXTEND_FS) {
        u_int64_t  newsize;
                vnode_t vp = p->p_fd->fd_cdir;

                if (newp == USER_ADDR_NULL || vp == NULL)
                        return (EINVAL);
                if ((error = hfs_getmountpoint(vp, &hfsmp)))
                        return (error);
                error = sysctl_quad(oldp, oldlenp, newp, newlen, &newsize);
                if (error)
                        return (error);
        
                error = hfs_extendfs(hfsmp, newsize, context);          
                return (error);

        } else if (name[0] == HFS_ENCODINGHINT) {
                size_t bufsize;
                size_t bytes;
                u_int32_t hint;
                u_int16_t *unicode_name;
                char *filename;

                bufsize = MAX(newlen * 3, MAXPATHLEN);
                MALLOC(filename, char *, newlen, M_TEMP, M_WAITOK);
                MALLOC(unicode_name, u_int16_t *, bufsize, M_TEMP, M_WAITOK);

                error = copyin(newp, (caddr_t)filename, newlen);
                if (error == 0) {
                        error = utf8_decodestr(filename, newlen - 1, unicode_name,
                                               &bytes, bufsize, 0, UTF_DECOMPOSED);
                        if (error == 0) {
                                hint = hfs_pickencoding(unicode_name, bytes / 2);
                                error = sysctl_int(oldp, oldlenp, USER_ADDR_NULL, 0, &hint);
                        }
                }
                FREE(unicode_name, M_TEMP);
                FREE(filename, M_TEMP);
                return (error);

        } else if (name[0] == HFS_ENABLE_JOURNALING) {
                // make the file system journaled...
                struct vnode *vp = p->p_fd->fd_cdir, *jvp;
                ExtendedVCB *vcb;
                struct cat_attr jnl_attr, jinfo_attr;
                struct cat_fork jnl_fork, jinfo_fork;
                void *jnl = NULL;
                int lockflags;

                /* Only root can enable journaling */
                if (!is_suser()) {
                        return (EPERM);
                }
                if (vp == NULL)
                        return EINVAL;

                hfsmp = VTOHFS(vp);
                if (hfsmp->hfs_flags & HFS_READ_ONLY) {
                        return EROFS;
                }
                if (HFSTOVCB(hfsmp)->vcbSigWord == kHFSSigWord) {
                        printf("hfs: can't make a plain hfs volume journaled.\n");
                        return EINVAL;
                }

                if (hfsmp->jnl) {
                    printf("hfs: volume @ mp 0x%x is already journaled!\n", vnode_mount(vp));
                    return EAGAIN;
                }

                vcb = HFSTOVCB(hfsmp);
                lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG | SFL_EXTENTS, HFS_EXCLUSIVE_LOCK);
                if (BTHasContiguousNodes(VTOF(vcb->catalogRefNum)) == 0 ||
                        BTHasContiguousNodes(VTOF(vcb->extentsRefNum)) == 0) {

                        printf("hfs: volume has a btree w/non-contiguous nodes.  can not enable journaling.\n");
                        hfs_systemfile_unlock(hfsmp, lockflags);
                        return EINVAL;
                }
                hfs_systemfile_unlock(hfsmp, lockflags);

                // make sure these both exist!
                if (   GetFileInfo(vcb, kHFSRootFolderID, ".journal_info_block", &jinfo_attr, &jinfo_fork) == 0
                        || GetFileInfo(vcb, kHFSRootFolderID, ".journal", &jnl_attr, &jnl_fork) == 0) {

                        return EINVAL;
                }

                hfs_sync(hfsmp->hfs_mp, MNT_WAIT, context);

                printf("hfs: Initializing the journal (joffset 0x%llx sz 0x%llx)...\n",
                           (off_t)name[2], (off_t)name[3]);

                jvp = hfsmp->hfs_devvp;
                jnl = journal_create(jvp,
                                                         (off_t)name[2] * (off_t)HFSTOVCB(hfsmp)->blockSize
                                                         + HFSTOVCB(hfsmp)->hfsPlusIOPosOffset,
                                                         (off_t)((unsigned)name[3]),
                                                         hfsmp->hfs_devvp,
                                                         hfsmp->hfs_phys_block_size,
                                                         0,
                                                         0,
                                                         hfs_sync_metadata, hfsmp->hfs_mp);

                if (jnl == NULL) {
                        printf("hfs: FAILED to create the journal!\n");
                        if (jvp && jvp != hfsmp->hfs_devvp) {
                                VNOP_CLOSE(jvp, hfsmp->hfs_flags & HFS_READ_ONLY ? FREAD : FREAD|FWRITE, context);
                        }
                        jvp = NULL;

                        return EINVAL;
                } 

                hfs_global_exclusive_lock_acquire(hfsmp);
                
                HFSTOVCB(hfsmp)->vcbJinfoBlock = name[1];
                HFSTOVCB(hfsmp)->vcbAtrb |= kHFSVolumeJournaledMask;
                hfsmp->jvp = jvp;
                hfsmp->jnl = jnl;

                // save this off for the hack-y check in hfs_remove()
                hfsmp->jnl_start        = (u_int32_t)name[2];
                hfsmp->jnl_size         = (off_t)((unsigned)name[3]);
                hfsmp->hfs_jnlinfoblkid = jinfo_attr.ca_fileid;
                hfsmp->hfs_jnlfileid    = jnl_attr.ca_fileid;

                vfs_setflags(hfsmp->hfs_mp, (uint64_t)((unsigned int)MNT_JOURNALED));

                hfs_global_exclusive_lock_release(hfsmp);
                hfs_flushvolumeheader(hfsmp, MNT_WAIT, 1);

                return 0;
        } else if (name[0] == HFS_DISABLE_JOURNALING) {
                // clear the journaling bit 
                struct vnode *vp = p->p_fd->fd_cdir;
                
                /* Only root can disable journaling */
                if (!is_suser()) {
                        return (EPERM);
                }
                if (vp == NULL)
                        return EINVAL;

                hfsmp = VTOHFS(vp);

                printf("hfs: disabling journaling for mount @ 0x%x\n", vnode_mount(vp));

                hfs_global_exclusive_lock_acquire(hfsmp);

                // Lights out for you buddy!
                journal_close(hfsmp->jnl);
                hfsmp->jnl = NULL;

                if (hfsmp->jvp && hfsmp->jvp != hfsmp->hfs_devvp) {
                        VNOP_CLOSE(hfsmp->jvp, hfsmp->hfs_flags & HFS_READ_ONLY ? FREAD : FREAD|FWRITE, context);
                }
                hfsmp->jvp = NULL;
                vfs_clearflags(hfsmp->hfs_mp, (uint64_t)((unsigned int)MNT_JOURNALED));
                hfsmp->jnl_start        = 0;
                hfsmp->hfs_jnlinfoblkid = 0;
                hfsmp->hfs_jnlfileid    = 0;
                
                HFSTOVCB(hfsmp)->vcbAtrb &= ~kHFSVolumeJournaledMask;
                
                hfs_global_exclusive_lock_release(hfsmp);
                hfs_flushvolumeheader(hfsmp, MNT_WAIT, 1);

                return 0;
        } else if (name[0] == HFS_GET_JOURNAL_INFO) {
                struct vnode *vp = p->p_fd->fd_cdir;
                off_t jnl_start, jnl_size;

                if (vp == NULL)
                        return EINVAL;

                hfsmp = VTOHFS(vp);
            if (hfsmp->jnl == NULL) {
                        jnl_start = 0;
                        jnl_size  = 0;
            } else {
                        jnl_start = (off_t)(hfsmp->jnl_start * HFSTOVCB(hfsmp)->blockSize) + (off_t)HFSTOVCB(hfsmp)->hfsPlusIOPosOffset;
                        jnl_size  = (off_t)hfsmp->jnl_size;
            }

            if ((error = copyout((caddr_t)&jnl_start, CAST_USER_ADDR_T(name[1]), sizeof(off_t))) != 0) {
                        return error;
                }
            if ((error = copyout((caddr_t)&jnl_size, CAST_USER_ADDR_T(name[2]), sizeof(off_t))) != 0) {
                        return error;
                }

                return 0;
        } else if (name[0] == HFS_SET_PKG_EXTENSIONS) {

            return set_package_extensions_table((void *)name[1], name[2], name[3]);
            
        } else if (name[0] == VFS_CTL_QUERY) {
        struct sysctl_req *req;
        struct vfsidctl vc;
            struct user_vfsidctl user_vc;
        struct mount *mp;
            struct vfsquery vq;
            boolean_t is_64_bit;
        
        is_64_bit = proc_is64bit(p); 
                req = CAST_DOWN(struct sysctl_req *, oldp);     /* we're new style vfs sysctl. */
        
        if (is_64_bit) {
            error = SYSCTL_IN(req, &user_vc, sizeof(user_vc));
            if (error) return (error);
            
            mp = vfs_getvfs(&user_vc.vc_fsid);
        } 
        else {
            error = SYSCTL_IN(req, &vc, sizeof(vc));
            if (error) return (error);
            
            mp = vfs_getvfs(&vc.vc_fsid);
        }
        if (mp == NULL) return (ENOENT);
        
                hfsmp = VFSTOHFS(mp);
                bzero(&vq, sizeof(vq));
                vq.vq_flags = hfsmp->hfs_notification_conditions;
                return SYSCTL_OUT(req, &vq, sizeof(vq));;
        };

        return (ENOTSUP);
}


static int
hfs_vfs_vget(struct mount *mp, ino64_t ino, struct vnode **vpp, __unused vfs_context_t context)
{
        return hfs_vget(VFSTOHFS(mp), (cnid_t)ino, vpp, 1);
}


/*
 * Look up an HFS object by ID.
 *
 * The object is returned with an iocount reference and the cnode locked.
 *
 * If the object is a file then it will represent the data fork.
 */
__private_extern__
int
hfs_vget(struct hfsmount *hfsmp, cnid_t cnid, struct vnode **vpp, int skiplock)
{
        struct vnode *vp = NULL;
        struct cat_desc cndesc;
        struct cat_attr cnattr;
        struct cat_fork cnfork;
        struct componentname cn;
        u_int32_t linkref = 0;
        int error;
        
        /* Check for cnids that should't be exported. */
        if ((cnid < kHFSFirstUserCatalogNodeID)
        &&  (cnid != kHFSRootFolderID && cnid != kHFSRootParentID))
                return (ENOENT);

        /* Don't export HFS Private Data dir. */
        if (cnid == hfsmp->hfs_privdir_desc.cd_cnid)
                return (ENOENT);

        /*
         * Check the hash first
         */
        vp = hfs_chash_getvnode(hfsmp->hfs_raw_dev, cnid, 0, skiplock);
        if (vp) {
                *vpp = vp;
                return(0);
        }

        bzero(&cndesc, sizeof(cndesc));
        bzero(&cnattr, sizeof(cnattr));
        bzero(&cnfork, sizeof(cnfork));

        /*
         * Not in hash, lookup in catalog
         */
        if (cnid == kHFSRootParentID) {
                static char hfs_rootname[] = "/";

                cndesc.cd_nameptr = &hfs_rootname[0];
                cndesc.cd_namelen = 1;
                cndesc.cd_parentcnid = kHFSRootParentID;
                cndesc.cd_cnid = kHFSRootFolderID;
                cndesc.cd_flags = CD_ISDIR;

                cnattr.ca_fileid = kHFSRootFolderID;
                cnattr.ca_nlink = 2;
                cnattr.ca_entries = 1;
                cnattr.ca_mode = (S_IFDIR | S_IRWXU | S_IRWXG | S_IRWXO);
        } else {
                int lockflags;

                lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG, HFS_SHARED_LOCK);
                error = cat_idlookup(hfsmp, cnid, &cndesc, &cnattr, &cnfork);
                hfs_systemfile_unlock(hfsmp, lockflags);

                if (error) {
                        *vpp = NULL;
                        return (error);
                }

                /*
                 * If we just looked up a raw hardlink inode,
                 * then finish initializing it.
                 */
                if ((cndesc.cd_parentcnid == hfsmp->hfs_privdir_desc.cd_cnid) &&
                    (bcmp(cndesc.cd_nameptr, HFS_INODE_PREFIX, HFS_INODE_PREFIX_LEN) == 0)) {
                        linkref = strtoul((const char*)&cndesc.cd_nameptr[HFS_INODE_PREFIX_LEN], NULL, 10);
                        cnattr.ca_rdev = linkref;

                        // patch up the parentcnid
                        if (cnattr.ca_attrblks != 0) {
                            cndesc.cd_parentcnid = cnattr.ca_attrblks;
                        }
                }
        }

        /*
         * Supply hfs_getnewvnode with a component name. 
         */
        MALLOC_ZONE(cn.cn_pnbuf, caddr_t, MAXPATHLEN, M_NAMEI, M_WAITOK);
        cn.cn_nameiop = LOOKUP;
        cn.cn_flags = ISLASTCN | HASBUF;
        cn.cn_context = NULL;
        cn.cn_pnlen = MAXPATHLEN;
        cn.cn_nameptr = cn.cn_pnbuf;
        cn.cn_namelen = cndesc.cd_namelen;
        cn.cn_hash = 0;
        cn.cn_consume = 0;
        bcopy(cndesc.cd_nameptr, cn.cn_nameptr, cndesc.cd_namelen + 1);

        /* XXX should we supply the parent as well... ? */
        error = hfs_getnewvnode(hfsmp, NULLVP, &cn, &cndesc, 0, &cnattr, &cnfork, &vp);
        if (error == 0 && linkref != 0) {
                VTOC(vp)->c_flag |= C_HARDLINK;
        }

        FREE_ZONE(cn.cn_pnbuf, cn.cn_pnlen, M_NAMEI);

        cat_releasedesc(&cndesc);
        *vpp = vp;
        if (vp && skiplock)
                hfs_unlock(VTOC(vp));
        return (error);
}


/*
 * Flush out all the files in a filesystem.
 */
static int
hfs_flushfiles(struct mount *mp, int flags, struct proc *p)
{
        struct hfsmount *hfsmp;
        struct vnode *skipvp = NULLVP;
        int quotafilecnt;
        int i;
        int error;

        hfsmp = VFSTOHFS(mp);

#if QUOTA
        /*
         * The open quota files have an indirect reference on
         * the root directory vnode.  We must account for this
         * extra reference when doing the intial vflush.
         */
        quotafilecnt = 0;
        if (((unsigned int)vfs_flags(mp)) & MNT_QUOTA) {

                /* Find out how many quota files we have open. */
                for (i = 0; i < MAXQUOTAS; i++) {
                        if (hfsmp->hfs_qfiles[i].qf_vp != NULLVP)
                                ++quotafilecnt;
                }

                /* Obtain the root vnode so we can skip over it. */
                skipvp = hfs_chash_getvnode(hfsmp->hfs_raw_dev, kHFSRootFolderID, 0, 0);
        }
#endif /* QUOTA */

        error = vflush(mp, skipvp, SKIPSYSTEM | SKIPSWAP | flags);
        if (error != 0)
                return(error);

        error = vflush(mp, skipvp, SKIPSYSTEM | flags);

#if QUOTA
        if (((unsigned int)vfs_flags(mp)) & MNT_QUOTA) {
                if (skipvp) {
                        /*
                         * See if there are additional references on the
                         * root vp besides the ones obtained from the open
                         * quota files and the hfs_chash_getvnode call above.
                         */
                        if ((error == 0) &&
                            (vnode_isinuse(skipvp,  quotafilecnt))) {
                                error = EBUSY;  /* root directory is still open */
                        }
                        hfs_unlock(VTOC(skipvp));
                        vnode_put(skipvp);
                }
                if (error && (flags & FORCECLOSE) == 0)
                        return (error);

                for (i = 0; i < MAXQUOTAS; i++) {
                        if (hfsmp->hfs_qfiles[i].qf_vp == NULLVP)
                                continue;
                        hfs_quotaoff(p, mp, i);
                }
                error = vflush(mp, NULLVP, SKIPSYSTEM | flags);
        }
#endif /* QUOTA */

        return (error);
}

/*
 * Update volume encoding bitmap (HFS Plus only)
 */
__private_extern__
void
hfs_setencodingbits(struct hfsmount *hfsmp, u_int32_t encoding)
{
#define  kIndexMacUkrainian     48  /* MacUkrainian encoding is 152 */
#define  kIndexMacFarsi         49  /* MacFarsi encoding is 140 */

        UInt32  index;

        switch (encoding) {
        case kTextEncodingMacUkrainian:
                index = kIndexMacUkrainian;
                break;
        case kTextEncodingMacFarsi:
                index = kIndexMacFarsi;
                break;
        default:
                index = encoding;
                break;
        }

        if (index < 64) {
                HFS_MOUNT_LOCK(hfsmp, TRUE)
                hfsmp->encodingsBitmap |= (u_int64_t)(1ULL << index);
                hfsmp->vcbFlags |= 0xFF00;
                HFS_MOUNT_UNLOCK(hfsmp, TRUE);
        }
}

/*
 * Update volume stats
 *
 * On journal volumes this will cause a volume header flush
 */
__private_extern__
int
hfs_volupdate(struct hfsmount *hfsmp, enum volop op, int inroot)
{
        struct timeval tv;

        microtime(&tv);

        lck_mtx_lock(&hfsmp->hfs_mutex);

        hfsmp->vcbFlags |= 0xFF00;
        hfsmp->hfs_mtime = tv.tv_sec;

        switch (op) {
        case VOL_UPDATE:
                break;
        case VOL_MKDIR:
                if (hfsmp->hfs_dircount != 0xFFFFFFFF)
                        ++hfsmp->hfs_dircount;
                if (inroot && hfsmp->vcbNmRtDirs != 0xFFFF)
                        ++hfsmp->vcbNmRtDirs;
                break;
        case VOL_RMDIR:
                if (hfsmp->hfs_dircount != 0)
                        --hfsmp->hfs_dircount;
                if (inroot && hfsmp->vcbNmRtDirs != 0xFFFF)
                        --hfsmp->vcbNmRtDirs;
                break;
        case VOL_MKFILE:
                if (hfsmp->hfs_filecount != 0xFFFFFFFF)
                        ++hfsmp->hfs_filecount;
                if (inroot && hfsmp->vcbNmFls != 0xFFFF)
                        ++hfsmp->vcbNmFls;
                break;
        case VOL_RMFILE:
                if (hfsmp->hfs_filecount != 0)
                        --hfsmp->hfs_filecount;
                if (inroot && hfsmp->vcbNmFls != 0xFFFF)
                        --hfsmp->vcbNmFls;
                break;
        }

        lck_mtx_unlock(&hfsmp->hfs_mutex);

        if (hfsmp->jnl) {
                hfs_flushvolumeheader(hfsmp, 0, 0);
        }

        return (0);
}


static int
hfs_flushMDB(struct hfsmount *hfsmp, int waitfor, int altflush)
{
        ExtendedVCB *vcb = HFSTOVCB(hfsmp);
        struct filefork *fp;
        HFSMasterDirectoryBlock *mdb;
        struct buf *bp = NULL;
        int retval;
        int sectorsize;
        ByteCount namelen;

        sectorsize = hfsmp->hfs_phys_block_size;
        retval = (int)buf_bread(hfsmp->hfs_devvp, (daddr64_t)HFS_PRI_SECTOR(sectorsize), sectorsize, NOCRED, &bp);
        if (retval) {
                if (bp)
                        buf_brelse(bp);
                return retval;
        }

        lck_mtx_lock(&hfsmp->hfs_mutex);

        mdb = (HFSMasterDirectoryBlock *)(buf_dataptr(bp) + HFS_PRI_OFFSET(sectorsize));
    
        mdb->drCrDate   = SWAP_BE32 (UTCToLocal(to_hfs_time(vcb->vcbCrDate)));
        mdb->drLsMod    = SWAP_BE32 (UTCToLocal(to_hfs_time(vcb->vcbLsMod)));
        mdb->drAtrb     = SWAP_BE16 (vcb->vcbAtrb);
        mdb->drNmFls    = SWAP_BE16 (vcb->vcbNmFls);
        mdb->drAllocPtr = SWAP_BE16 (vcb->nextAllocation);
        mdb->drClpSiz   = SWAP_BE32 (vcb->vcbClpSiz);
        mdb->drNxtCNID  = SWAP_BE32 (vcb->vcbNxtCNID);
        mdb->drFreeBks  = SWAP_BE16 (vcb->freeBlocks);

        namelen = strlen(vcb->vcbVN);
        retval = utf8_to_hfs(vcb, namelen, vcb->vcbVN, mdb->drVN);
        /* Retry with MacRoman in case that's how it was exported. */
        if (retval)
                retval = utf8_to_mac_roman(namelen, vcb->vcbVN, mdb->drVN);
        
        mdb->drVolBkUp  = SWAP_BE32 (UTCToLocal(to_hfs_time(vcb->vcbVolBkUp)));
        mdb->drWrCnt    = SWAP_BE32 (vcb->vcbWrCnt);
        mdb->drNmRtDirs = SWAP_BE16 (vcb->vcbNmRtDirs);
        mdb->drFilCnt   = SWAP_BE32 (vcb->vcbFilCnt);
        mdb->drDirCnt   = SWAP_BE32 (vcb->vcbDirCnt);
        
        bcopy(vcb->vcbFndrInfo, mdb->drFndrInfo, sizeof(mdb->drFndrInfo));

        fp = VTOF(vcb->extentsRefNum);
        mdb->drXTExtRec[0].startBlock = SWAP_BE16 (fp->ff_extents[0].startBlock);
        mdb->drXTExtRec[0].blockCount = SWAP_BE16 (fp->ff_extents[0].blockCount);
        mdb->drXTExtRec[1].startBlock = SWAP_BE16 (fp->ff_extents[1].startBlock);
        mdb->drXTExtRec[1].blockCount = SWAP_BE16 (fp->ff_extents[1].blockCount);
        mdb->drXTExtRec[2].startBlock = SWAP_BE16 (fp->ff_extents[2].startBlock);
        mdb->drXTExtRec[2].blockCount = SWAP_BE16 (fp->ff_extents[2].blockCount);
        mdb->drXTFlSize = SWAP_BE32 (fp->ff_blocks * vcb->blockSize);
        mdb->drXTClpSiz = SWAP_BE32 (fp->ff_clumpsize);
        FTOC(fp)->c_flag &= ~C_MODIFIED;
        
        fp = VTOF(vcb->catalogRefNum);
        mdb->drCTExtRec[0].startBlock = SWAP_BE16 (fp->ff_extents[0].startBlock);
        mdb->drCTExtRec[0].blockCount = SWAP_BE16 (fp->ff_extents[0].blockCount);
        mdb->drCTExtRec[1].startBlock = SWAP_BE16 (fp->ff_extents[1].startBlock);
        mdb->drCTExtRec[1].blockCount = SWAP_BE16 (fp->ff_extents[1].blockCount);
        mdb->drCTExtRec[2].startBlock = SWAP_BE16 (fp->ff_extents[2].startBlock);
        mdb->drCTExtRec[2].blockCount = SWAP_BE16 (fp->ff_extents[2].blockCount);
        mdb->drCTFlSize = SWAP_BE32 (fp->ff_blocks * vcb->blockSize);
        mdb->drCTClpSiz = SWAP_BE32 (fp->ff_clumpsize);
        FTOC(fp)->c_flag &= ~C_MODIFIED;

        MarkVCBClean( vcb );

        lck_mtx_unlock(&hfsmp->hfs_mutex);

        /* If requested, flush out the alternate MDB */
        if (altflush) {
                struct buf *alt_bp = NULL;

                if (buf_meta_bread(hfsmp->hfs_devvp, hfsmp->hfs_alt_id_sector, sectorsize, NOCRED, &alt_bp) == 0) {
                        bcopy(mdb, (char *)buf_dataptr(alt_bp) + HFS_ALT_OFFSET(sectorsize), kMDBSize);

                        (void) VNOP_BWRITE(alt_bp);
                } else if (alt_bp)
                        buf_brelse(alt_bp);
        }

        if (waitfor != MNT_WAIT)
                buf_bawrite(bp);
        else 
                retval = VNOP_BWRITE(bp);

        return (retval);
}

/*
 *  Flush any dirty in-memory mount data to the on-disk
 *  volume header.
 *
 *  Note: the on-disk volume signature is intentionally
 *  not flushed since the on-disk "H+" and "HX" signatures
 *  are always stored in-memory as "H+".
 */
__private_extern__
int
hfs_flushvolumeheader(struct hfsmount *hfsmp, int waitfor, int altflush)
{
        ExtendedVCB *vcb = HFSTOVCB(hfsmp);
        struct filefork *fp;
        HFSPlusVolumeHeader *volumeHeader;
        int retval;
        struct buf *bp;
        int i;
        int sectorsize;
        daddr64_t priIDSector;
        int critical = 0;
        u_int16_t  signature;
        u_int16_t  hfsversion;

        if (hfsmp->hfs_flags & HFS_READ_ONLY) {
                return(0);
        }
        if (vcb->vcbSigWord == kHFSSigWord)
                return hfs_flushMDB(hfsmp, waitfor, altflush);

        if (altflush)
                critical = 1;
        sectorsize = hfsmp->hfs_phys_block_size;
        priIDSector = (daddr64_t)((vcb->hfsPlusIOPosOffset / sectorsize) +
                                  HFS_PRI_SECTOR(sectorsize));

        if (hfs_start_transaction(hfsmp) != 0) {
            return EINVAL;
        }

        retval = (int)buf_meta_bread(hfsmp->hfs_devvp, priIDSector, sectorsize, NOCRED, &bp);
        if (retval) {
                if (bp)
                        buf_brelse(bp);

                hfs_end_transaction(hfsmp);

                printf("HFS: err %d reading VH blk (%s)\n", retval, vcb->vcbVN);
                return (retval);
        }

        if (hfsmp->jnl) {
                journal_modify_block_start(hfsmp->jnl, bp);
        }

        volumeHeader = (HFSPlusVolumeHeader *)((char *)buf_dataptr(bp) + HFS_PRI_OFFSET(sectorsize));

        /*
         * Sanity check what we just read.
         */
        signature = SWAP_BE16 (volumeHeader->signature);
        hfsversion   = SWAP_BE16 (volumeHeader->version);
        if ((signature != kHFSPlusSigWord && signature != kHFSXSigWord) ||
            (hfsversion < kHFSPlusVersion) || (hfsversion > 100) ||
            (SWAP_BE32 (volumeHeader->blockSize) != vcb->blockSize)) {
#if 1
                panic("HFS: corrupt VH on %s, sig 0x%04x, ver %d, blksize %d",
                      vcb->vcbVN, signature, hfsversion,
                      SWAP_BE32 (volumeHeader->blockSize));
#endif
                printf("HFS: corrupt VH blk (%s)\n", vcb->vcbVN);
                buf_brelse(bp);
                return (EIO);
        }

        /*
         * For embedded HFS+ volumes, update create date if it changed
         * (ie from a setattrlist call)
         */
        if ((vcb->hfsPlusIOPosOffset != 0) &&
            (SWAP_BE32 (volumeHeader->createDate) != vcb->localCreateDate)) {
                struct buf *bp2;
                HFSMasterDirectoryBlock *mdb;

                retval = (int)buf_meta_bread(hfsmp->hfs_devvp, (daddr64_t)HFS_PRI_SECTOR(sectorsize),
                                sectorsize, NOCRED, &bp2);
                if (retval) {
                        if (bp2)
                                buf_brelse(bp2);
                        retval = 0;
                } else {
                        mdb = (HFSMasterDirectoryBlock *)(buf_dataptr(bp2) +
                                HFS_PRI_OFFSET(sectorsize));

                        if ( SWAP_BE32 (mdb->drCrDate) != vcb->localCreateDate )
                          {
                                if (hfsmp->jnl) {
                                    journal_modify_block_start(hfsmp->jnl, bp2);
                                }

                                mdb->drCrDate = SWAP_BE32 (vcb->localCreateDate);       /* pick up the new create date */

                                if (hfsmp->jnl) {
                                        journal_modify_block_end(hfsmp->jnl, bp2);
                                } else {
                                        (void) VNOP_BWRITE(bp2);                /* write out the changes */
                                }
                          }
                        else
                          {
                                buf_brelse(bp2);                                                /* just release it */
                          }
                  }     
        }

        if (1 /* hfsmp->jnl == 0 */) {
                lck_mtx_lock(&hfsmp->hfs_mutex);
        }

        /* Note: only update the lower 16 bits worth of attributes */
        volumeHeader->attributes       = SWAP_BE32 (vcb->vcbAtrb);
        volumeHeader->journalInfoBlock = SWAP_BE32 (vcb->vcbJinfoBlock);
        if (hfsmp->jnl) {
                volumeHeader->lastMountedVersion = SWAP_BE32 (kHFSJMountVersion);
        } else {
                volumeHeader->lastMountedVersion = SWAP_BE32 (kHFSPlusMountVersion);
        }
        volumeHeader->createDate        = SWAP_BE32 (vcb->localCreateDate);  /* volume create date is in local time */
        volumeHeader->modifyDate        = SWAP_BE32 (to_hfs_time(vcb->vcbLsMod));
        volumeHeader->backupDate        = SWAP_BE32 (to_hfs_time(vcb->vcbVolBkUp));
        volumeHeader->fileCount         = SWAP_BE32 (vcb->vcbFilCnt);
        volumeHeader->folderCount       = SWAP_BE32 (vcb->vcbDirCnt);
        volumeHeader->totalBlocks       = SWAP_BE32 (vcb->totalBlocks);
        volumeHeader->freeBlocks        = SWAP_BE32 (vcb->freeBlocks);
        volumeHeader->nextAllocation    = SWAP_BE32 (vcb->nextAllocation);
        volumeHeader->rsrcClumpSize     = SWAP_BE32 (vcb->vcbClpSiz);
        volumeHeader->dataClumpSize     = SWAP_BE32 (vcb->vcbClpSiz);
        volumeHeader->nextCatalogID     = SWAP_BE32 (vcb->vcbNxtCNID);
        volumeHeader->writeCount        = SWAP_BE32 (vcb->vcbWrCnt);
        volumeHeader->encodingsBitmap   = SWAP_BE64 (vcb->encodingsBitmap);

        if (bcmp(vcb->vcbFndrInfo, volumeHeader->finderInfo, sizeof(volumeHeader->finderInfo)) != 0) {
                bcopy(vcb->vcbFndrInfo, volumeHeader->finderInfo, sizeof(volumeHeader->finderInfo));
                critical = 1;
        }

        /* Sync Extents over-flow file meta data */
        fp = VTOF(vcb->extentsRefNum);
        if (FTOC(fp)->c_flag & C_MODIFIED) {
                for (i = 0; i < kHFSPlusExtentDensity; i++) {
                        volumeHeader->extentsFile.extents[i].startBlock =
                                SWAP_BE32 (fp->ff_extents[i].startBlock);
                        volumeHeader->extentsFile.extents[i].blockCount =
                                SWAP_BE32 (fp->ff_extents[i].blockCount);
                }
                volumeHeader->extentsFile.logicalSize = SWAP_BE64 (fp->ff_size);
                volumeHeader->extentsFile.totalBlocks = SWAP_BE32 (fp->ff_blocks);
                volumeHeader->extentsFile.clumpSize   = SWAP_BE32 (fp->ff_clumpsize);
                FTOC(fp)->c_flag &= ~C_MODIFIED;
        }

        /* Sync Catalog file meta data */
        fp = VTOF(vcb->catalogRefNum);
        if (FTOC(fp)->c_flag & C_MODIFIED) {
                for (i = 0; i < kHFSPlusExtentDensity; i++) {
                        volumeHeader->catalogFile.extents[i].startBlock =
                                SWAP_BE32 (fp->ff_extents[i].startBlock);
                        volumeHeader->catalogFile.extents[i].blockCount =
                                SWAP_BE32 (fp->ff_extents[i].blockCount);
                }
                volumeHeader->catalogFile.logicalSize = SWAP_BE64 (fp->ff_size);
                volumeHeader->catalogFile.totalBlocks = SWAP_BE32 (fp->ff_blocks);
                volumeHeader->catalogFile.clumpSize   = SWAP_BE32 (fp->ff_clumpsize);
                FTOC(fp)->c_flag &= ~C_MODIFIED;
        }

        /* Sync Allocation file meta data */
        fp = VTOF(vcb->allocationsRefNum);
        if (FTOC(fp)->c_flag & C_MODIFIED) {
                for (i = 0; i < kHFSPlusExtentDensity; i++) {
                        volumeHeader->allocationFile.extents[i].startBlock =
                                SWAP_BE32 (fp->ff_extents[i].startBlock);
                        volumeHeader->allocationFile.extents[i].blockCount =
                                SWAP_BE32 (fp->ff_extents[i].blockCount);
                }
                volumeHeader->allocationFile.logicalSize = SWAP_BE64 (fp->ff_size);
                volumeHeader->allocationFile.totalBlocks = SWAP_BE32 (fp->ff_blocks);
                volumeHeader->allocationFile.clumpSize   = SWAP_BE32 (fp->ff_clumpsize);
                FTOC(fp)->c_flag &= ~C_MODIFIED;
        }

        /* Sync Attribute file meta data */
        if (hfsmp->hfs_attribute_vp) {
                fp = VTOF(hfsmp->hfs_attribute_vp);
                for (i = 0; i < kHFSPlusExtentDensity; i++) {
                        volumeHeader->attributesFile.extents[i].startBlock =
                                SWAP_BE32 (fp->ff_extents[i].startBlock);
                        volumeHeader->attributesFile.extents[i].blockCount =
                                SWAP_BE32 (fp->ff_extents[i].blockCount);
                }
                FTOC(fp)->c_flag &= ~C_MODIFIED;
                volumeHeader->attributesFile.logicalSize = SWAP_BE64 (fp->ff_size);
                volumeHeader->attributesFile.totalBlocks = SWAP_BE32 (fp->ff_blocks);
                volumeHeader->attributesFile.clumpSize   = SWAP_BE32 (fp->ff_clumpsize);
        }

        vcb->vcbFlags &= 0x00FF;

        if (1 /* hfsmp->jnl == 0 */) {
                lck_mtx_unlock(&hfsmp->hfs_mutex);
        }

        /* If requested, flush out the alternate volume header */
        if (altflush && hfsmp->hfs_alt_id_sector) {
                struct buf *alt_bp = NULL;

                if (buf_meta_bread(hfsmp->hfs_devvp, hfsmp->hfs_alt_id_sector, sectorsize, NOCRED, &alt_bp) == 0) {
                        if (hfsmp->jnl) {
                                journal_modify_block_start(hfsmp->jnl, alt_bp);
                        }

                        bcopy(volumeHeader, (char *)buf_dataptr(alt_bp) + HFS_ALT_OFFSET(sectorsize), kMDBSize);

                        if (hfsmp->jnl) {
                                journal_modify_block_end(hfsmp->jnl, alt_bp);
                        } else {
                                (void) VNOP_BWRITE(alt_bp);
                        }
                } else if (alt_bp)
                        buf_brelse(alt_bp);
        }

        if (hfsmp->jnl) {
                journal_modify_block_end(hfsmp->jnl, bp);
        } else {
                if (waitfor != MNT_WAIT)
                        buf_bawrite(bp);
                else {
                    retval = VNOP_BWRITE(bp);
                    /* When critical data changes, flush the device cache */
                    if (critical && (retval == 0)) {
                        (void) VNOP_IOCTL(hfsmp->hfs_devvp, DKIOCSYNCHRONIZECACHE,
                                         NULL, FWRITE, NULL);
                    }
                }
        }
        hfs_end_transaction(hfsmp);
 
        return (retval);
}


/*
 * Extend a file system.
 */
__private_extern__
int
hfs_extendfs(struct hfsmount *hfsmp, u_int64_t newsize, vfs_context_t context)
{
        struct proc *p = vfs_context_proc(context);
        kauth_cred_t cred = vfs_context_ucred(context);
        struct  vnode *vp;
        struct  vnode *devvp;
        struct  buf *bp;
        struct  filefork *fp = NULL;
        ExtendedVCB  *vcb;
        struct  cat_fork forkdata;
        u_int64_t  oldsize;
        u_int64_t  newblkcnt;
        u_int64_t  prev_phys_block_count;
        u_int32_t  addblks;
        u_int64_t  sectorcnt;
        u_int32_t  sectorsize;
        daddr64_t  prev_alt_sector;
        daddr_t    bitmapblks;
        int  lockflags;
        int  error;

        devvp = hfsmp->hfs_devvp;
        vcb = HFSTOVCB(hfsmp);

        /*
         * - HFS Plus file systems only. 
         * - Journaling must be enabled.
         * - No embedded volumes.
         */
        if ((vcb->vcbSigWord == kHFSSigWord) ||
             (hfsmp->jnl == NULL) ||
             (vcb->hfsPlusIOPosOffset != 0)) {
                return (EPERM);
        }
        /*
         * If extending file system by non-root, then verify
         * ownership and check permissions.
         */
        if (suser(cred, NULL)) {
                error = hfs_vget(hfsmp, kHFSRootFolderID, &vp, 0);

                if (error)
                        return (error);
                error = hfs_owner_rights(hfsmp, VTOC(vp)->c_uid, cred, p, 0);
                if (error == 0) {
                        error = hfs_write_access(vp, cred, p, false);
                }
                hfs_unlock(VTOC(vp));
                vnode_put(vp);
                if (error)
                        return (error);

                error = vnode_authorize(devvp, NULL, KAUTH_VNODE_READ_DATA | KAUTH_VNODE_WRITE_DATA, context);
                if (error)
                        return (error);
        }
        if (VNOP_IOCTL(devvp, DKIOCGETBLOCKSIZE, (caddr_t)&sectorsize, 0, context)) {
                return (ENXIO);
        }
        if (sectorsize != hfsmp->hfs_phys_block_size) {
                return (ENXIO);
        }
        if (VNOP_IOCTL(devvp, DKIOCGETBLOCKCOUNT, (caddr_t)&sectorcnt, 0, context)) {
                return (ENXIO);
        }
        if ((sectorsize * sectorcnt) < newsize) {
                printf("hfs_extendfs: not enough space on device\n");
                return (ENOSPC);
        }
        oldsize = (u_int64_t)hfsmp->totalBlocks * (u_int64_t)hfsmp->blockSize;

        /*
         * Validate new size.
         */
        if ((newsize <= oldsize) || (newsize % sectorsize)) {
                printf("hfs_extendfs: invalid size\n");
                return (EINVAL);
        }
        newblkcnt = newsize / vcb->blockSize;
        if (newblkcnt > (u_int64_t)0xFFFFFFFF)
                return (EOVERFLOW);

        addblks = newblkcnt - vcb->totalBlocks;

        printf("hfs_extendfs: growing %s by %d blocks\n", vcb->vcbVN, addblks);
        /*
         * Enclose changes inside a transaction.
         */
        if (hfs_start_transaction(hfsmp) != 0) {
                return (EINVAL);
        }

        lockflags = hfs_systemfile_lock(hfsmp, SFL_EXTENTS | SFL_BITMAP, HFS_EXCLUSIVE_LOCK);
        vp = vcb->allocationsRefNum;
        fp = VTOF(vp);
        bcopy(&fp->ff_data, &forkdata, sizeof(forkdata));

        /*
         * Calculate additional space required (if any) by allocation bitmap.
         */
        bitmapblks = roundup(newblkcnt / 8, vcb->vcbVBMIOSize) / vcb->blockSize;
        if (bitmapblks > (daddr_t)fp->ff_blocks)
                bitmapblks -= fp->ff_blocks;
        else
                bitmapblks = 0;

        if (bitmapblks > 0) {
                daddr64_t blkno;
                daddr_t blkcnt;

                /*
                 * Add a new extent to the allocation bitmap file.
                 */
                error = AddFileExtent(vcb, fp, vcb->totalBlocks, bitmapblks);
                if (error) {
                        printf("hfs_extendfs: error %d adding extents\n", error);
                        goto out;
                }
                blkcnt = bitmapblks;
                blkno  = (daddr64_t)fp->ff_blocks;
                fp->ff_blocks += bitmapblks;
                fp->ff_size += (u_int64_t)bitmapblks * (u_int64_t)vcb->blockSize;
                VTOC(vp)->c_blocks = fp->ff_blocks;
                /*
                 * Zero out the new bitmap blocks.
                 */
                {
        
                        bp = NULL;
                        while (blkcnt > 0) {
                                error = (int)buf_meta_bread(vp, blkno, vcb->blockSize, NOCRED, &bp);
                                if (error) {
                                        if (bp) {
                                                buf_brelse(bp);
                                        }
                                        break;
                                }
                                bzero((char *)buf_dataptr(bp), vcb->blockSize);
                                buf_markaged(bp);
                                error = (int)buf_bwrite(bp);
                                if (error)
                                        break;
                                --blkcnt;
                                ++blkno;
                        }
                }
                if (error) {
                        printf("hfs_extendfs: error %d  clearing blocks\n", error);
                        goto out;
                }
                /*
                 * Mark the new bitmap space as allocated.
                 */
                error = BlockMarkAllocated(vcb, vcb->totalBlocks, bitmapblks);
                if (error) {
                        printf("hfs_extendfs: error %d setting bitmap\n", error);
                        goto out;
                }
        }
        /*
         * Mark the new alternate VH as allocated.
         */
        if (vcb->blockSize == 512)
                error = BlockMarkAllocated(vcb, vcb->totalBlocks + addblks - 2, 2);
        else
                error = BlockMarkAllocated(vcb, vcb->totalBlocks + addblks - 1, 1);
        if (error) {
                printf("hfs_extendfs: error %d setting bitmap (VH)\n", error);
                goto out;
        }
        /*
         * Mark the old alternate VH as free.
         */
        if (vcb->blockSize == 512)
                (void) BlockMarkFree(vcb, vcb->totalBlocks - 2, 2);
        else 
                (void) BlockMarkFree(vcb, vcb->totalBlocks - 1, 1);
        /*
         * Adjust file system variables for new space.
         */
        prev_phys_block_count = hfsmp->hfs_phys_block_count;
        prev_alt_sector = hfsmp->hfs_alt_id_sector;

        vcb->totalBlocks += addblks;
        vcb->freeBlocks += addblks - bitmapblks;
        hfsmp->hfs_phys_block_count = newsize / sectorsize;
        hfsmp->hfs_alt_id_sector = (hfsmp->hfsPlusIOPosOffset / sectorsize) +
                                  HFS_ALT_SECTOR(sectorsize, hfsmp->hfs_phys_block_count);
        MarkVCBDirty(vcb);
        error = hfs_flushvolumeheader(hfsmp, MNT_WAIT, HFS_ALTFLUSH);
        if (error) {
                printf("hfs_extendfs: couldn't flush volume headers (%d)", error);
                /*
                 * Restore to old state.
                 */
                fp->ff_size -= (u_int64_t)bitmapblks * (u_int64_t)vcb->blockSize;
                vcb->totalBlocks -= addblks;
                vcb->freeBlocks -= addblks - bitmapblks;
                hfsmp->hfs_phys_block_count = prev_phys_block_count;
                hfsmp->hfs_alt_id_sector = prev_alt_sector;
                MarkVCBDirty(vcb);
                if (vcb->blockSize == 512)
                        (void) BlockMarkAllocated(vcb, vcb->totalBlocks - 2, 2);
                else
                        (void) BlockMarkAllocated(vcb, vcb->totalBlocks - 1, 1);
                goto out;
        }
        /*
         * Invalidate the old alternate volume header.
         */
        bp = NULL;
        if (prev_alt_sector) {
                if (buf_meta_bread(hfsmp->hfs_devvp, prev_alt_sector, sectorsize,
                                   NOCRED, &bp) == 0) {
                        journal_modify_block_start(hfsmp->jnl, bp);
        
                        bzero((char *)buf_dataptr(bp) + HFS_ALT_OFFSET(sectorsize), kMDBSize);
        
                        journal_modify_block_end(hfsmp->jnl, bp);
                } else if (bp) {
                        buf_brelse(bp);
                }
        }
out:
        if (error && fp) {
                /* Restore allocation fork. */
                bcopy(&forkdata, &fp->ff_data, sizeof(forkdata));
                VTOC(vp)->c_blocks = fp->ff_blocks;

        }
        hfs_systemfile_unlock(hfsmp, lockflags);
        hfs_end_transaction(hfsmp);

        return (error);
}

#define HFS_MIN_SIZE  (32LL * 1024LL * 1024LL)

/*
 * Truncate a file system (while still mounted).
 */
__private_extern__
int
hfs_truncatefs(struct hfsmount *hfsmp, u_int64_t newsize, __unused vfs_context_t context)
{
        struct vnode* rvp = NULL;
        struct  buf *bp = NULL;
        u_int64_t oldsize;
        u_int32_t newblkcnt;
        u_int32_t reclaimblks;
        int lockflags = 0;
        int transaction_begun = 0;
        int error;

        /*
         * Grab the root vnode to serialize with another hfs_truncatefs call.
         */
        error = hfs_vget(hfsmp, kHFSRootFolderID, &rvp, 0);
        if (error) {
                return (error);
        }
        /*
         * - HFS Plus file systems only. 
         * - Journaling must be enabled.
         * - No embedded volumes.
         */
        if ((hfsmp->hfs_flags & HFS_STANDARD) ||
            (hfsmp->jnl == NULL) ||
            (hfsmp->hfsPlusIOPosOffset != 0)) {
                error = EPERM;
                goto out;
        }
        oldsize = (u_int64_t)hfsmp->totalBlocks * (u_int64_t)hfsmp->blockSize;
        newblkcnt = newsize / hfsmp->blockSize;
        reclaimblks = hfsmp->totalBlocks - newblkcnt;

        /* Make sure new size is valid. */
        if ((newsize < HFS_MIN_SIZE) ||
            (newsize >= oldsize) ||
            (newsize % hfsmp->hfs_phys_block_size)) {
                error = EINVAL;
                goto out;
        }
        /* Make sure there's enough space to work with. */
        if (reclaimblks > (hfsmp->freeBlocks / 4)) {
                error = ENOSPC;
                goto out;
        }

        printf("hfs_truncatefs: shrinking %s by %d blocks out of %d\n",
               hfsmp->vcbVN, reclaimblks, hfsmp->totalBlocks);

        if (hfs_start_transaction(hfsmp) != 0) {
                error = EINVAL;
                goto out;
        }
        transaction_begun = 1;

        /*
         * Look for files that have blocks beyond newblkcnt.
         */
        if (hfs_isallocated(hfsmp, newblkcnt, reclaimblks - 1)) {
                /*
                 * hfs_reclaimspace will use separate transactions when
                 * relocating files (so we don't overwhelm the journal).
                 */
                hfs_end_transaction(hfsmp);
                transaction_begun = 0;

                /* Attempt to reclaim some space. */ 
                if (hfs_reclaimspace(hfsmp, newblkcnt) != 0) {
                        printf("hfs_truncatefs: couldn't reclaim space on %s\n", hfsmp->vcbVN);
                        error = ENOSPC;
                        goto out;
                }
                if (hfs_start_transaction(hfsmp) != 0) {
                        error = EINVAL;
                        goto out;
                }
                transaction_begun = 1;
                
                /* Check if we're clear now. */
                if (hfs_isallocated(hfsmp, newblkcnt, reclaimblks - 1)) {
                        printf("hfs_truncatefs: didn't reclaim enough space on %s\n", hfsmp->vcbVN);
                        error = ENOSPC;
                        goto out;
                }
        }
        lockflags = hfs_systemfile_lock(hfsmp, SFL_EXTENTS | SFL_BITMAP, HFS_EXCLUSIVE_LOCK);

        /*
         * Mark the old alternate volume header as free. 
         * We don't bother shrinking allocation bitmap file.
         */
         if (hfsmp->blockSize == 512) 
                (void) BlockMarkFree(hfsmp, hfsmp->totalBlocks - 2, 2);
        else 
                (void) BlockMarkFree(hfsmp, hfsmp->totalBlocks - 1, 1);

        /*
         * Allocate last block for alternate volume header.
         */
        if (hfsmp->blockSize == 512)
                error = BlockMarkAllocated(hfsmp, newblkcnt - 2, 2);
        else
                error = BlockMarkAllocated(hfsmp, newblkcnt - 1, 1);

        if (error) {
                goto out;
        }

        /*
         * Invalidate the existing alternate volume header.
         */
        if (hfsmp->hfs_alt_id_sector) {
                if (buf_meta_bread(hfsmp->hfs_devvp, hfsmp->hfs_alt_id_sector,
                                   hfsmp->hfs_phys_block_size, NOCRED, &bp) == 0) {
                        journal_modify_block_start(hfsmp->jnl, bp);
        
                        bzero((void*)((char *)buf_dataptr(bp) + HFS_ALT_OFFSET(hfsmp->hfs_phys_block_size)), kMDBSize);
        
                        journal_modify_block_end(hfsmp->jnl, bp);
                } else if (bp) {
                        buf_brelse(bp);
                }
                bp = NULL;
        }

        /*
         * Adjust file system variables and flush them to disk.
         */
        hfsmp->freeBlocks -= hfsmp->totalBlocks - newblkcnt;
        hfsmp->totalBlocks = newblkcnt;
        hfsmp->hfs_phys_block_count = newsize / hfsmp->hfs_phys_block_size;
        hfsmp->hfs_alt_id_sector = HFS_ALT_SECTOR(hfsmp->hfs_phys_block_size, hfsmp->hfs_phys_block_count);
        MarkVCBDirty(hfsmp);
        error = hfs_flushvolumeheader(hfsmp, MNT_WAIT, HFS_ALTFLUSH);
        if (error)
                panic("hfs_truncatefs: unexpected error flushing volume header (%d)\n", error);
out:
        if (lockflags) {
                hfs_systemfile_unlock(hfsmp, lockflags);
        }
        if (transaction_begun) {
                hfs_end_transaction(hfsmp);
        }
        if (rvp) {
                hfs_unlock(VTOC(rvp));
                vnode_put(rvp);
        }
        return (error);
}

/*
 * Reclaim space at the end of a file system.
 */
static int
hfs_reclaimspace(struct hfsmount *hfsmp, u_long startblk)
{
        struct vnode *vp = NULL;
        FCB *fcb;
        struct BTreeIterator * iterator = NULL;
        struct FSBufferDescriptor btdata;
        struct HFSPlusCatalogFile filerec;
        u_int32_t  saved_next_allocation;
        cnid_t * cnidbufp;
        size_t cnidbufsize;
        int filecnt;
        int maxfilecnt;
        u_long block;
        int lockflags;
        int i;
        int error;

        /* 
         * Check if Attributes file overlaps.
         */
        if (hfsmp->hfs_attribute_vp) {
                struct filefork *fp;
        
                fp = VTOF(hfsmp->hfs_attribute_vp);
                for (i = 0; i < kHFSPlusExtentDensity; ++i) {
                        block = fp->ff_extents[i].startBlock +
                                fp->ff_extents[i].blockCount;
                        if (block >= startblk) {
                                printf("hfs_reclaimspace: Attributes file can't move\n");
                                return (EPERM);
                        }
                }
        }

        /* For now we'll move a maximum of 16,384 files. */
        maxfilecnt = MIN(hfsmp->hfs_filecount, 16384);
        cnidbufsize = maxfilecnt * sizeof(cnid_t);
        if (kmem_alloc(kernel_map, (vm_offset_t *)&cnidbufp, cnidbufsize)) {
                return (ENOMEM);
        }       
        if (kmem_alloc(kernel_map, (vm_offset_t *)&iterator, sizeof(*iterator))) {
                kmem_free(kernel_map, (vm_offset_t)cnidbufp, cnidbufsize);
                return (ENOMEM);
        }       

        saved_next_allocation = hfsmp->nextAllocation;
        hfsmp->nextAllocation = hfsmp->hfs_metazone_start;

        fcb = VTOF(hfsmp->hfs_catalog_vp);
        bzero(iterator, sizeof(*iterator));

        btdata.bufferAddress = &filerec;
        btdata.itemSize = sizeof(filerec);
        btdata.itemCount = 1;

        /* Keep the Catalog file locked during iteration. */
        lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG, HFS_SHARED_LOCK);
        error = BTIterateRecord(fcb, kBTreeFirstRecord, iterator, NULL, NULL);
        if (error) {
                hfs_systemfile_unlock(hfsmp, lockflags);
                goto out;
        }

        /*
         * Iterate over all the catalog records looking for files
         * that overlap into the space we're trying to free up.
         */
        for (filecnt = 0; filecnt < maxfilecnt; ) {
                error = BTIterateRecord(fcb, kBTreeNextRecord, iterator, &btdata, NULL);
                if (error) {
                        if (error == btNotFound)
                                error = 0;
                        break;
                }
                if (filerec.recordType != kHFSPlusFileRecord ||
                    filerec.fileID == hfsmp->hfs_jnlfileid)
                        continue;
                /* 
                 * Check if either fork overlaps target space.
                 */
                for (i = 0; i < kHFSPlusExtentDensity; ++i) {
                        block = filerec.dataFork.extents[i].startBlock +
                                filerec.dataFork.extents[i].blockCount;
                        if (block >= startblk) {
                                if (filerec.fileID == hfsmp->hfs_jnlfileid) {
                                        printf("hfs_reclaimspace: cannot move active journal\n");
                                        error = EPERM;
                                        break;
                                }
                                cnidbufp[filecnt++] = filerec.fileID;
                                break;
                        }
                        block = filerec.resourceFork.extents[i].startBlock +
                                filerec.resourceFork.extents[i].blockCount;
                        if (block >= startblk) {
                                cnidbufp[filecnt++] = filerec.fileID;
                                break;
                        }
                }
        }
        /* All done with catalog. */
        hfs_systemfile_unlock(hfsmp, lockflags);
        if (error)
                goto out;

        /* Now move any files that are in the way. */
        for (i = 0; i < filecnt; ++i) {
                struct vnode * rvp;

                if (hfs_vget(hfsmp, cnidbufp[i], &vp, 0) != 0)
                        continue;

                /* Relocate any data fork blocks. */
                if (VTOF(vp)->ff_blocks > 0) {
                        error = hfs_relocate(vp, hfsmp->hfs_metazone_end + 1, kauth_cred_get(), current_proc());
                }
                if (error) 
                        break;

                /* Relocate any resource fork blocks. */
                if ((VTOC((vp))->c_blocks - VTOF((vp))->ff_blocks) > 0) {
                        error = hfs_vgetrsrc(hfsmp, vp, &rvp, current_proc());
                        if (error)
                                break;
                        error = hfs_relocate(rvp, hfsmp->hfs_metazone_end + 1, kauth_cred_get(), current_proc());
                        vnode_put(rvp);
                        if (error)
                                break;
                }
                hfs_unlock(VTOC(vp));
                vnode_put(vp);
                vp = NULL;
        }
        if (vp) {
                hfs_unlock(VTOC(vp));
                vnode_put(vp);
                vp = NULL;
        }

        /*
         * Note: this implementation doesn't handle overflow extents.
         */
out:
        kmem_free(kernel_map, (vm_offset_t)iterator, sizeof(*iterator));
        kmem_free(kernel_map, (vm_offset_t)cnidbufp, cnidbufsize);

        /* On errors restore the roving allocation pointer. */
        if (error) {
                hfsmp->nextAllocation = saved_next_allocation;
        }
        return (error);
}


/*
 * Get file system attributes.
 */
static int
hfs_vfs_getattr(struct mount *mp, struct vfs_attr *fsap, __unused vfs_context_t context)
{
        ExtendedVCB *vcb = VFSTOVCB(mp);
        struct hfsmount *hfsmp = VFSTOHFS(mp);
        u_long freeCNIDs;

        freeCNIDs = (u_long)0xFFFFFFFF - (u_long)hfsmp->vcbNxtCNID;

        VFSATTR_RETURN(fsap, f_objcount, (uint64_t)hfsmp->vcbFilCnt + (uint64_t)hfsmp->vcbDirCnt);
        VFSATTR_RETURN(fsap, f_filecount, (uint64_t)hfsmp->vcbFilCnt);
        VFSATTR_RETURN(fsap, f_dircount, (uint64_t)hfsmp->vcbDirCnt);
        VFSATTR_RETURN(fsap, f_maxobjcount, (uint64_t)0xFFFFFFFF);
        VFSATTR_RETURN(fsap, f_iosize, (size_t)(MAX_UPL_TRANSFER * PAGE_SIZE));
        VFSATTR_RETURN(fsap, f_blocks, (uint64_t)hfsmp->totalBlocks);
        VFSATTR_RETURN(fsap, f_bfree, (uint64_t)hfs_freeblks(hfsmp, 0));
        VFSATTR_RETURN(fsap, f_bavail, (uint64_t)hfs_freeblks(hfsmp, 1));
        VFSATTR_RETURN(fsap, f_bsize, (uint32_t)vcb->blockSize);
        /* XXX needs clarification */
        VFSATTR_RETURN(fsap, f_bused, hfsmp->totalBlocks - hfs_freeblks(hfsmp, 1));
        /* Maximum files is constrained by total blocks. */
        VFSATTR_RETURN(fsap, f_files, (uint64_t)(hfsmp->totalBlocks - 2));
        VFSATTR_RETURN(fsap, f_ffree, MIN((uint64_t)freeCNIDs, (uint64_t)hfs_freeblks(hfsmp, 1)));

        fsap->f_fsid.val[0] = hfsmp->hfs_raw_dev;
        fsap->f_fsid.val[1] = vfs_typenum(mp);
        VFSATTR_SET_SUPPORTED(fsap, f_fsid);

        VFSATTR_RETURN(fsap, f_signature, vcb->vcbSigWord);
        VFSATTR_RETURN(fsap, f_carbon_fsid, 0);

        if (VFSATTR_IS_ACTIVE(fsap, f_capabilities)) {
                vol_capabilities_attr_t *cap;
        
                cap = &fsap->f_capabilities;

                if (hfsmp->hfs_flags & HFS_STANDARD) {
                        cap->capabilities[VOL_CAPABILITIES_FORMAT] =
                                VOL_CAP_FMT_PERSISTENTOBJECTIDS |
                                VOL_CAP_FMT_CASE_PRESERVING |
                                VOL_CAP_FMT_FAST_STATFS;
                } else {
                        cap->capabilities[VOL_CAPABILITIES_FORMAT] =
                                VOL_CAP_FMT_PERSISTENTOBJECTIDS |
                                VOL_CAP_FMT_SYMBOLICLINKS |
                                VOL_CAP_FMT_HARDLINKS |
                                VOL_CAP_FMT_JOURNAL |
                                (hfsmp->jnl ? VOL_CAP_FMT_JOURNAL_ACTIVE : 0) |
                                (hfsmp->hfs_flags & HFS_CASE_SENSITIVE ? VOL_CAP_FMT_CASE_SENSITIVE : 0) |
                                VOL_CAP_FMT_CASE_PRESERVING |
                                VOL_CAP_FMT_FAST_STATFS | 
                                VOL_CAP_FMT_2TB_FILESIZE;
                }
                cap->capabilities[VOL_CAPABILITIES_INTERFACES] =
                        VOL_CAP_INT_SEARCHFS |
                        VOL_CAP_INT_ATTRLIST |
                        VOL_CAP_INT_NFSEXPORT |
                        VOL_CAP_INT_READDIRATTR |
                        VOL_CAP_INT_EXCHANGEDATA |
                        VOL_CAP_INT_ALLOCATE |
                        VOL_CAP_INT_VOL_RENAME |
                        VOL_CAP_INT_ADVLOCK |
                        VOL_CAP_INT_FLOCK;
                cap->capabilities[VOL_CAPABILITIES_RESERVED1] = 0;
                cap->capabilities[VOL_CAPABILITIES_RESERVED2] = 0;

                cap->valid[VOL_CAPABILITIES_FORMAT] =
                        VOL_CAP_FMT_PERSISTENTOBJECTIDS |
                        VOL_CAP_FMT_SYMBOLICLINKS |
                        VOL_CAP_FMT_HARDLINKS |
                        VOL_CAP_FMT_JOURNAL |
                        VOL_CAP_FMT_JOURNAL_ACTIVE |
                        VOL_CAP_FMT_NO_ROOT_TIMES |
                        VOL_CAP_FMT_SPARSE_FILES |
                        VOL_CAP_FMT_ZERO_RUNS |
                        VOL_CAP_FMT_CASE_SENSITIVE |
                        VOL_CAP_FMT_CASE_PRESERVING |
                        VOL_CAP_FMT_FAST_STATFS |
                        VOL_CAP_FMT_2TB_FILESIZE;
                cap->valid[VOL_CAPABILITIES_INTERFACES] =
                        VOL_CAP_INT_SEARCHFS |
                        VOL_CAP_INT_ATTRLIST |
                        VOL_CAP_INT_NFSEXPORT |
                        VOL_CAP_INT_READDIRATTR |
                        VOL_CAP_INT_EXCHANGEDATA |
                        VOL_CAP_INT_COPYFILE |
                        VOL_CAP_INT_ALLOCATE |
                        VOL_CAP_INT_VOL_RENAME |
                        VOL_CAP_INT_ADVLOCK |
                        VOL_CAP_INT_FLOCK;
                cap->valid[VOL_CAPABILITIES_RESERVED1] = 0;
                cap->valid[VOL_CAPABILITIES_RESERVED2] = 0;
                VFSATTR_SET_SUPPORTED(fsap, f_capabilities);
        }
        if (VFSATTR_IS_ACTIVE(fsap, f_attributes)) {
                vol_attributes_attr_t *attrp = &fsap->f_attributes;

                attrp->validattr.commonattr = ATTR_CMN_VALIDMASK;
                attrp->validattr.volattr = ATTR_VOL_VALIDMASK & ~ATTR_VOL_INFO;
                attrp->validattr.dirattr = ATTR_DIR_VALIDMASK;
                attrp->validattr.fileattr = ATTR_FILE_VALIDMASK;
                attrp->validattr.forkattr = 0;

                attrp->nativeattr.commonattr = ATTR_CMN_VALIDMASK;
                attrp->nativeattr.volattr = ATTR_VOL_VALIDMASK & ~ATTR_VOL_INFO;
                attrp->nativeattr.dirattr = ATTR_DIR_VALIDMASK;
                attrp->nativeattr.fileattr = ATTR_FILE_VALIDMASK;
                attrp->nativeattr.forkattr = 0;
                VFSATTR_SET_SUPPORTED(fsap, f_attributes);
        }       
        fsap->f_create_time.tv_sec = hfsmp->vcbCrDate;
        fsap->f_create_time.tv_nsec = 0;
        VFSATTR_SET_SUPPORTED(fsap, f_create_time);
        fsap->f_modify_time.tv_sec = hfsmp->vcbLsMod;
        fsap->f_modify_time.tv_nsec = 0;
        VFSATTR_SET_SUPPORTED(fsap, f_modify_time);

        fsap->f_backup_time.tv_sec = hfsmp->vcbVolBkUp;
        fsap->f_backup_time.tv_nsec = 0;
        VFSATTR_SET_SUPPORTED(fsap, f_backup_time);
        if (VFSATTR_IS_ACTIVE(fsap, f_fssubtype)) {
                uint16_t subtype = 0;

                /*
                 * Subtypes (flavors) for HFS
                 *   0:   Mac OS Extended
                 *   1:   Mac OS Extended (Journaled) 
                 *   2:   Mac OS Extended (Case Sensitive) 
                 *   3:   Mac OS Extended (Case Sensitive, Journaled) 
                 *   4 - 127:   Reserved
                 * 128:   Mac OS Standard
                 * 
                 */
                if (hfsmp->hfs_flags & HFS_STANDARD) {
                        subtype = HFS_SUBTYPE_STANDARDHFS;
                } else /* HFS Plus */ {
                        if (hfsmp->jnl)
                                subtype |= HFS_SUBTYPE_JOURNALED;
                        if (hfsmp->hfs_flags & HFS_CASE_SENSITIVE)
                                subtype |= HFS_SUBTYPE_CASESENSITIVE;
                }
                fsap->f_fssubtype = subtype;
                VFSATTR_SET_SUPPORTED(fsap, f_fssubtype);
        }

        if (VFSATTR_IS_ACTIVE(fsap, f_vol_name)) {
                strncpy(fsap->f_vol_name, hfsmp->vcbVN, MAXPATHLEN);
                fsap->f_vol_name[MAXPATHLEN - 1] = 0;
                VFSATTR_SET_SUPPORTED(fsap, f_vol_name);
        }
        return (0);
}

/*
 * Perform a volume rename.  Requires the FS' root vp.
 */
static int
hfs_rename_volume(struct vnode *vp, const char *name, proc_t p)
{
        ExtendedVCB *vcb = VTOVCB(vp);
        struct cnode *cp = VTOC(vp);
        struct hfsmount *hfsmp = VTOHFS(vp);
        struct cat_desc to_desc;
        struct cat_desc todir_desc;
        struct cat_desc new_desc;
        cat_cookie_t cookie;
        int lockflags;
        int error = 0;

        /*
         * Ignore attempts to rename a volume to a zero-length name.
         */
        if (name[0] == 0)
                return(0);

        bzero(&to_desc, sizeof(to_desc));
        bzero(&todir_desc, sizeof(todir_desc));
        bzero(&new_desc, sizeof(new_desc));
        bzero(&cookie, sizeof(cookie));

        todir_desc.cd_parentcnid = kHFSRootParentID;
        todir_desc.cd_cnid = kHFSRootFolderID;
        todir_desc.cd_flags = CD_ISDIR;

        to_desc.cd_nameptr = name;
        to_desc.cd_namelen = strlen(name);
        to_desc.cd_parentcnid = kHFSRootParentID;
        to_desc.cd_cnid = cp->c_cnid;
        to_desc.cd_flags = CD_ISDIR;

        if ((error = hfs_lock(cp, HFS_EXCLUSIVE_LOCK)) == 0) {
                if ((error = hfs_start_transaction(hfsmp)) == 0) {
                        if ((error = cat_preflight(hfsmp, CAT_RENAME, &cookie, p)) == 0) {
                                lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG, HFS_EXCLUSIVE_LOCK);

                                error = cat_rename(hfsmp, &cp->c_desc, &todir_desc, &to_desc, &new_desc);

                                /*
                                 * If successful, update the name in the VCB, ensure it's terminated.
                                 */
                                if (!error) {
                                        strncpy(vcb->vcbVN, name, sizeof(vcb->vcbVN));
                                        vcb->vcbVN[sizeof(vcb->vcbVN) - 1] = 0;
                                }

                                hfs_systemfile_unlock(hfsmp, lockflags);
                                cat_postflight(hfsmp, &cookie, p);
                        
                                if (error)
                                        vcb->vcbFlags |= 0xFF00;
                                (void) hfs_flushvolumeheader(hfsmp, MNT_WAIT, 0);
                        }
                        hfs_end_transaction(hfsmp);
                }                       
                if (!error) {
                        /* Release old allocated name buffer */
                        if (cp->c_desc.cd_flags & CD_HASBUF) {
                                char *name = cp->c_desc.cd_nameptr;
                
                                cp->c_desc.cd_nameptr = 0;
                                cp->c_desc.cd_namelen = 0;
                                cp->c_desc.cd_flags &= ~CD_HASBUF;
                                vfs_removename(name);
                        }                       
                        /* Update cnode's catalog descriptor */
                        replace_desc(cp, &new_desc);
                        vcb->volumeNameEncodingHint = new_desc.cd_encoding;
                        cp->c_touch_chgtime = TRUE;
                }

                hfs_unlock(cp);
        }
        
        return(error);
}

/*
 * Get file system attributes.
 */
static int
hfs_vfs_setattr(struct mount *mp, struct vfs_attr *fsap, __unused vfs_context_t context)
{
        kauth_cred_t cred = vfs_context_ucred(context);
        int error = 0;

        /*
         * Must be superuser or owner of filesystem to change volume attributes
         */
        if (!kauth_cred_issuser(cred) && (kauth_cred_getuid(cred) != vfs_statfs(mp)->f_owner))
                return(EACCES);

        if (VFSATTR_IS_ACTIVE(fsap, f_vol_name)) {
                vnode_t root_vp;
                
                error = hfs_vfs_root(mp, &root_vp, context);
                if (error)
                        goto out;

                error = hfs_rename_volume(root_vp, fsap->f_vol_name, vfs_context_proc(context));
                (void) vnode_put(root_vp);
                if (error)
                        goto out;

                VFSATTR_SET_SUPPORTED(fsap, f_vol_name);
        }

out:
        return error;
}


/*
 * hfs vfs operations.
 */
struct vfsops hfs_vfsops = {
        hfs_mount,
        hfs_start,
        hfs_unmount,
        hfs_vfs_root,
        hfs_quotactl,
        hfs_vfs_getattr,        /* was hfs_statfs */
        hfs_sync,
        hfs_vfs_vget,
        hfs_fhtovp,
        hfs_vptofh,
        hfs_init,
        hfs_sysctl,
        hfs_vfs_setattr
};