[apple/hfs.git] / core / hfs_vfsops.c

/*
 * Copyright (c) 1999-2015 Apple 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 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/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 <sys/fslog.h>
#include <sys/ubc.h>

/* for parsing boot-args */
#include <pexpert/pexpert.h>


#include <kern/locks.h>

#include "hfs_journal.h"

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

#include <libkern/crypto/md5.h>
#include <uuid/uuid.h>

#include "hfs_iokit.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 "hfs_btreeio.h"
#include "hfs_kdebug.h"
#include "hfs_cprotect.h"

#include "FileMgrInternal.h"
#include "BTreesInternal.h"

#define HFS_MOUNT_DEBUG 1

/* Enable/disable debugging code for live volume resizing, defined in hfs_resize.c */
extern int hfs_resize_debug;

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;
lck_grp_t *  hfs_spinlock_group;

extern struct vnodeopv_desc hfs_vnodeop_opv_desc;

#if CONFIG_HFS_STD
extern struct vnodeopv_desc hfs_std_vnodeop_opv_desc;
static int hfs_flushMDB(struct hfsmount *hfsmp, int waitfor, int altflush);
#endif

/* not static so we can re-use in hfs_readwrite.c for build_path calls */
int hfs_vfs_vget(struct mount *mp, ino64_t ino, struct vnode **vpp, vfs_context_t context);

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_init(struct vfsconf *vfsp);
static void hfs_locks_destroy(struct hfsmount *hfsmp);
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_vptofh(struct vnode *vp, int *fhlenp, unsigned char *fhp, vfs_context_t context);
static void hfs_syncer_free(struct hfsmount *hfsmp);

void hfs_initialize_allocator (struct hfsmount *hfsmp);
int hfs_teardown_allocator (struct hfsmount *hfsmp);

int hfs_mount(struct mount *mp, vnode_t  devvp, user_addr_t data, vfs_context_t context);
int hfs_mountfs(struct vnode *devvp, struct mount *mp, struct hfs_mount_args *args, int journal_replay_only, vfs_context_t context);
int hfs_reload(struct mount *mp);
int hfs_statfs(struct mount *mp, register struct vfsstatfs *sbp, vfs_context_t context);
int hfs_sync(struct mount *mp, int waitfor, vfs_context_t context);
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);
int hfs_unmount(struct mount *mp, int mntflags, vfs_context_t context);

static int hfs_journal_replay(vnode_t devvp, vfs_context_t context);

#if HFS_LEAK_DEBUG

#include <libkern/OSAtomic.h>
#include <IOKit/IOLib.h>

int hfs_active_mounts;

#endif

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

int
hfs_mount(struct mount *mp, vnode_t devvp, user_addr_t data, vfs_context_t context)
{

#if HFS_LEAK_DEBUG

#warning HFS_LEAK_DEBUG is on

        hfs_alloc_trace_enable();

#endif

        struct proc *p = vfs_context_proc(context);
        struct hfsmount *hfsmp = NULL;
        struct hfs_mount_args args;
        int retval = E_NONE;
        u_int32_t cmdflags;

        if (data && (retval = copyin(data, (caddr_t)&args, sizeof(args)))) {
                if (HFS_MOUNT_DEBUG) {
                        printf("hfs_mount: copyin returned %d for fs\n", retval);
                }
                return (retval);
        }
        cmdflags = (u_int32_t)vfs_flags(mp) & MNT_CMDFLAGS;
        if (cmdflags & MNT_UPDATE) {
                hfs_assert(data);

                hfsmp = VFSTOHFS(mp);

                /* Reload incore data after an fsck. */
                if (cmdflags & MNT_RELOAD) {
                        if (vfs_isrdonly(mp)) {
                                int error = hfs_reload(mp);
                                if (error && HFS_MOUNT_DEBUG) {
                                        printf("hfs_mount: hfs_reload returned %d on %s \n", error, hfsmp->vcbVN);
                                }
                                return error;
                        }
                        else {
                                if (HFS_MOUNT_DEBUG) {
                                        printf("hfs_mount: MNT_RELOAD not supported on rdwr filesystem %s\n", hfsmp->vcbVN);
                                }
                                return (EINVAL);
                        }
                }

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

                        /* Set flag to indicate that a downgrade to read-only
                         * is in progress and therefore block any further 
                         * modifications to the file system.
                         */
                        hfs_lock_global (hfsmp, HFS_EXCLUSIVE_LOCK);
                        hfsmp->hfs_flags |= HFS_RDONLY_DOWNGRADE;
                        hfsmp->hfs_downgrading_thread = current_thread();
                        hfs_unlock_global (hfsmp);
                        hfs_syncer_free(hfsmp);
            
                        /* use hfs_sync to push out System (btree) files */
                        retval = hfs_sync(mp, MNT_WAIT, context);
                        if (retval && ((cmdflags & MNT_FORCE) == 0)) {
                                hfsmp->hfs_flags &= ~HFS_RDONLY_DOWNGRADE;
                                hfsmp->hfs_downgrading_thread = NULL;
                                if (HFS_MOUNT_DEBUG) {
                                        printf("hfs_mount: VFS_SYNC returned %d during b-tree sync of %s \n", retval, hfsmp->vcbVN);
                                }
                                goto out;
                        }
                
                        flags = WRITECLOSE;
                        if (cmdflags & MNT_FORCE)
                                flags |= FORCECLOSE;
                                
                        if ((retval = hfs_flushfiles(mp, flags, p))) {
                                hfsmp->hfs_flags &= ~HFS_RDONLY_DOWNGRADE;
                                hfsmp->hfs_downgrading_thread = NULL;
                                if (HFS_MOUNT_DEBUG) {
                                        printf("hfs_mount: hfs_flushfiles returned %d on %s \n", retval, hfsmp->vcbVN);
                                }
                                goto out;
                        }

                        /* mark the volume cleanly unmounted */
                        hfsmp->vcbAtrb |= kHFSVolumeUnmountedMask;
                        retval = hfs_flushvolumeheader(hfsmp, HFS_FVH_WAIT);
                        hfsmp->hfs_flags |= HFS_READ_ONLY;

                        /*
                         * Close down the journal. 
                         *
                         * NOTE: It is critically important to close down the journal
                         * and have it issue all pending I/O prior to calling VNOP_FSYNC below.
                         * In a journaled environment it is expected that the journal be
                         * the only actor permitted to issue I/O for metadata blocks in HFS.
                         * If we were to call VNOP_FSYNC prior to closing down the journal,
                         * we would inadvertantly issue (and wait for) the I/O we just 
                         * initiated above as part of the flushvolumeheader call.
                         * 
                         * To avoid this, we follow the same order of operations as in
                         * unmount and issue the journal_close prior to calling VNOP_FSYNC.
                         */
        
                        if (hfsmp->jnl) {
                                hfs_lock_global (hfsmp, HFS_EXCLUSIVE_LOCK);

                            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_unlock_global (hfsmp);

                vfs_clearflags(hfsmp->hfs_mp, MNT_JOURNALED);
                        }

                        /*
                         * Write out any pending I/O still outstanding against the device node
                         * now that the journal has been closed.
                         */
                        if (retval == 0) {
                                vnode_get(hfsmp->hfs_devvp);
                                retval = VNOP_FSYNC(hfsmp->hfs_devvp, MNT_WAIT, context);
                                vnode_put(hfsmp->hfs_devvp);
                        }

                        if (retval) {
                                if (HFS_MOUNT_DEBUG) {
                                        printf("hfs_mount: FSYNC on devvp returned %d for fs %s\n", retval, hfsmp->vcbVN);
                                }
                                hfsmp->hfs_flags &= ~HFS_RDONLY_DOWNGRADE;
                                hfsmp->hfs_downgrading_thread = NULL;
                                hfsmp->hfs_flags &= ~HFS_READ_ONLY;
                                goto out;
                        }
                
                        if (hfsmp->hfs_flags & HFS_SUMMARY_TABLE) {
                                if (hfsmp->hfs_summary_table) {
                                        int err = 0;
                                        /* 
                                         * Take the bitmap lock to serialize against a concurrent bitmap scan still in progress 
                                         */
                                        if (hfsmp->hfs_allocation_vp) {
                                                err = hfs_lock (VTOC(hfsmp->hfs_allocation_vp), HFS_EXCLUSIVE_LOCK, HFS_LOCK_DEFAULT);
                                        }
                                        hfs_free(hfsmp->hfs_summary_table, hfsmp->hfs_summary_bytes);
                                        hfsmp->hfs_summary_table = NULL;
                                        hfsmp->hfs_flags &= ~HFS_SUMMARY_TABLE;
                                        if (err == 0 && hfsmp->hfs_allocation_vp){
                                                hfs_unlock (VTOC(hfsmp->hfs_allocation_vp));
                                        }
                                }
                        }

                        hfsmp->hfs_downgrading_thread = NULL;
                }

                /* Change to a writable file system. */
                if (vfs_iswriteupgrade(mp)) {
                        /*
                         * On inconsistent disks, do not allow read-write mount
                         * unless it is the boot volume being mounted.
                         */
                        if (!(vfs_flags(mp) & MNT_ROOTFS) &&
                                        (hfsmp->vcbAtrb & kHFSVolumeInconsistentMask)) {
                                if (HFS_MOUNT_DEBUG) {
                                        printf("hfs_mount: attempting to mount inconsistent non-root volume %s\n",  (hfsmp->vcbVN));
                                }
                                retval = EINVAL;
                                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_lock_global (hfsmp, HFS_EXCLUSIVE_LOCK);

                                /* We provide the mount point twice here: The first is used as
                                 * an opaque argument to be passed back when hfs_sync_metadata
                                 * is called.  The second is provided to the throttling code to
                                 * indicate which mount's device should be used when accounting
                                 * for metadata writes.
                                 */
                                hfsmp->jnl = journal_open(hfsmp->jvp,
                                                hfs_blk_to_bytes(hfsmp->jnl_start, HFSTOVCB(hfsmp)->blockSize) + (off_t)HFSTOVCB(hfsmp)->hfsPlusIOPosOffset,
                                                hfsmp->jnl_size,
                                                hfsmp->hfs_devvp,
                                                hfsmp->hfs_logical_block_size,
                                                jflags,
                                                0,
                                                hfs_sync_metadata, hfsmp->hfs_mp,
                                                hfsmp->hfs_mp);
                                
                                /*
                                 * Set up the trim callback function so that we can add
                                 * recently freed extents to the free extent cache once
                                 * the transaction that freed them is written to the
                                 * journal on disk.
                                 */
                                if (hfsmp->jnl)
                                        journal_trim_set_callback(hfsmp->jnl, hfs_trim_callback, hfsmp);
                                
                                hfs_unlock_global (hfsmp);

                                if (hfsmp->jnl == NULL) {
                                        if (HFS_MOUNT_DEBUG) {
                                                printf("hfs_mount: journal_open == NULL; couldn't be opened on %s \n", (hfsmp->vcbVN));
                                        }
                                        retval = EINVAL;
                                        goto out;
                                } else {
                                        hfsmp->hfs_flags &= ~HFS_NEED_JNL_RESET;
                    vfs_setflags(hfsmp->hfs_mp, MNT_JOURNALED);
                                }
                        }

                        /* See if we need to erase unused Catalog nodes due to <rdar://problem/6947811>. */
                        retval = hfs_erase_unused_nodes(hfsmp);
                        if (retval != E_NONE) {
                                if (HFS_MOUNT_DEBUG) {
                                        printf("hfs_mount: hfs_erase_unused_nodes returned %d for fs %s\n", retval, hfsmp->vcbVN);
                                }
                                goto out;
                        }

                        /* If this mount point was downgraded from read-write 
                         * to read-only, clear that information as we are now 
                         * moving back to read-write.
                         */
                        hfsmp->hfs_flags &= ~HFS_RDONLY_DOWNGRADE;
                        hfsmp->hfs_downgrading_thread = NULL;

                        /* mark the volume dirty (clear clean unmount bit) */
                        hfsmp->vcbAtrb &= ~kHFSVolumeUnmountedMask;

                        retval = hfs_flushvolumeheader(hfsmp, HFS_FVH_WAIT);
                        if (retval != E_NONE) {
                                if (HFS_MOUNT_DEBUG) {
                                        printf("hfs_mount: hfs_flushvolumeheader returned %d for fs %s\n", retval, hfsmp->vcbVN);
                                }
                                goto out;
                        }
                
                        /* Only clear HFS_READ_ONLY after a successful write */
                        hfsmp->hfs_flags &= ~HFS_READ_ONLY;


                        if (!(hfsmp->hfs_flags & (HFS_READ_ONLY | HFS_STANDARD))) {
                                /* Setup private/hidden directories for hardlinks. */
                                hfs_privatedir_init(hfsmp, FILE_HARDLINKS);
                                hfs_privatedir_init(hfsmp, DIR_HARDLINKS);

                                hfs_remove_orphans(hfsmp);

                                /*
                                 * Since we're upgrading to a read-write mount, allow
                                 * hot file clustering if conditions allow.
                                 *
                                 * Note: this normally only would happen if you booted
                                 *       single-user and upgraded the mount to read-write
                                 *
                                 * Note: at this point we are not allowed to fail the
                                 *       mount operation because the HotFile init code
                                 *       in hfs_recording_init() will lookup vnodes with
                                 *       VNOP_LOOKUP() which hangs vnodes off the mount
                                 *       (and if we were to fail, VFS is not prepared to
                                 *       clean that up at this point.  Since HotFiles are
                                 *       optional, this is not a big deal.
                                 */
                                if (ISSET(hfsmp->hfs_flags, HFS_METADATA_ZONE)
                                        && (!ISSET(hfsmp->hfs_flags, HFS_SSD)
                                                || ISSET(hfsmp->hfs_flags, HFS_CS_HOTFILE_PIN))) {
                                        hfs_recording_init(hfsmp);
                                }                                       
                                /* Force ACLs on HFS+ file systems. */
                                if (vfs_extendedsecurity(HFSTOVFS(hfsmp)) == 0) {
                                        vfs_setextendedsecurity(HFSTOVFS(hfsmp));
                                }
                        }
                }

                /* Update file system parameters. */
                retval = hfs_changefs(mp, &args);
                if (retval &&  HFS_MOUNT_DEBUG) {
                        printf("hfs_mount: hfs_changefs returned %d for %s\n", retval, hfsmp->vcbVN);
                }

        } else /* not an update request */ {
                /* Set the mount flag to indicate that we support volfs  */
                vfs_setflags(mp, (u_int64_t)((unsigned int)MNT_DOVOLFS));

                retval = hfs_mountfs(devvp, mp, data ? &args : NULL, 0, context);
                if (retval) { 
                        const char *name = vnode_getname(devvp);
                        printf("hfs_mount: hfs_mountfs returned error=%d for device %s\n", retval, (name ? name : "unknown-dev"));
                        if (name) {
                                vnode_putname(name);
                        }
                        goto out;
                }

                /* After hfs_mountfs succeeds, we should have valid hfsmp */
                hfsmp = VFSTOHFS(mp);

                /* Set up the maximum defrag file size */
                hfsmp->hfs_defrag_max = HFS_INITIAL_DEFRAG_SIZE;


                if (!data) {
                        // Root mount

                        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. */
                        hfsmp->reserveBlocks = ((u_int64_t)hfsmp->totalBlocks * HFS_MINFREE) / 100;
                        hfsmp->reserveBlocks = MIN(hfsmp->reserveBlocks, HFS_MAXRESERVE / hfsmp->blockSize);
                }

#if HFS_LEAK_DEBUG
                OSIncrementAtomic(&hfs_active_mounts);
#endif
        }

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;
        int lockflags;
        int error;

        args = (struct hfs_changefs_cargs *)cargs;

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

        lockflags = hfs_systemfile_lock(args->hfsmp, SFL_CATALOG, HFS_SHARED_LOCK);
        error = cat_lookup(args->hfsmp, &cp->c_desc, 0, 0, &cndesc, &cnattr, NULL, NULL);
        hfs_systemfile_unlock(args->hfsmp, lockflags);
        if (error) {
                /*
                 * 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) {
                        strlcpy((char *)vcb->vcbVN, (const char *)cp->c_desc.cd_nameptr, NAME_MAX+1);
                        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;
        struct hfs_changefs_cargs cargs;
        u_int32_t mount_flags;

#if CONFIG_HFS_STD
        u_int32_t old_encoding = 0;
        hfs_to_unicode_func_t   get_unicode_func;
        unicode_to_hfs_func_t   get_hfsname_func = NULL;
#endif

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

        hfsmp->hfs_flags |= HFS_IN_CHANGEFS;
        
        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, (u_int64_t)((unsigned int)MNT_UNKNOWNPERMISSIONS));  /* Just say "No". */
                retval = EINVAL;
                goto exit;
        }
        if (mount_flags & MNT_UNKNOWNPERMISSIONS)
                hfsmp->hfs_flags |= HFS_UNKNOWN_PERMS;
        else
                hfsmp->hfs_flags &= ~HFS_UNKNOWN_PERMS;

        namefix = permfix = 0;

        /*
         * Tracking of hot files requires up-to-date access times.  So if
         * access time updates are disabled, we must also disable hot files.
         */
        if (mount_flags & MNT_NOATIME) {
                (void) hfs_recording_suspend(hfsmp);
        }
        
        /* 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;
                }
        }
        
#if CONFIG_HFS_STD
        /* Change the hfs encoding value (hfs only) */
        if ((vcb->vcbSigWord == kHFSSigWord)    &&
            (args->hfs_encoding != (u_int32_t)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;
        }
#endif

        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 CONFIG_HFS_STD
        /*
         * 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) {
                /* HFS standard only */
                hfsmp->hfs_get_hfsname = get_hfsname_func;
                vcb->volumeNameEncodingHint = args->hfs_encoding;
                (void) hfs_relconverter(old_encoding);
        }
#endif

exit:
        hfsmp->hfs_flags &= ~HFS_IN_CHANGEFS;
        return (retval);
}


struct hfs_reload_cargs {
        struct hfsmount *hfsmp;
        int             error;
};

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

        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) && (cp->c_fileid >= kHFSFirstUserCatalogNodeID)) {
                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 */
                lockflags = hfs_systemfile_lock(args->hfsmp, SFL_CATALOG, HFS_SHARED_LOCK);
                args->error = cat_idlookup(args->hfsmp, cp->c_fileid, 0, 0, &desc, &cp->c_attr, datafork);
                hfs_systemfile_unlock(args->hfsmp, lockflags);
                if (args->error) {
                        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.
 */
int
hfs_reload(struct mount *mountp)
{
        register struct vnode *devvp;
        struct buf *bp;
        int error, i;
        struct hfsmount *hfsmp;
        struct HFSPlusVolumeHeader *vhp;
        ExtendedVCB *vcb;
        struct filefork *forkp;
        struct cat_desc cndesc;
        struct hfs_reload_cargs args;
        daddr64_t priIDSector;

        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.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.
         */
        priIDSector = (daddr64_t)((vcb->hfsPlusIOPosOffset / hfsmp->hfs_logical_block_size) + 
                        HFS_PRI_SECTOR(hfsmp->hfs_logical_block_size));

        error = (int)buf_meta_bread(hfsmp->hfs_devvp,
                        HFS_PHYSBLK_ROUNDDOWN(priIDSector, hfsmp->hfs_log_per_phys),
                        hfsmp->hfs_physical_block_size, NOCRED, &bp);
        if (error) {
                if (bp != NULL)
                        buf_brelse(bp);
                return (error);
        }

        vhp = (HFSPlusVolumeHeader *) (buf_dataptr(bp) + HFS_PRI_OFFSET(hfsmp->hfs_physical_block_size));

        /* 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);
        HFS_UPDATE_NEXT_ALLOCATION(vcb, 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, 0, 0, &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 directories. */
        hfs_privatedir_init(hfsmp, FILE_HARDLINKS);
        hfs_privatedir_init(hfsmp, DIR_HARDLINKS);

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

__unused
static uint64_t tv_to_usecs(struct timeval *tv)
{
        return tv->tv_sec * 1000000ULL + tv->tv_usec;
}

// Returns TRUE if b - a >= usecs
static bool hfs_has_elapsed (const struct timeval *a,
                                                         const struct timeval *b,
                                                         uint64_t usecs)
{
    struct timeval diff;
    timersub(b, a, &diff);
    return diff.tv_sec * 1000000ULL + diff.tv_usec >= usecs;
}
        
void hfs_syncer(void *arg, __unused wait_result_t wr)
{
    struct hfsmount *hfsmp = arg;
    struct timeval   now;

        KDBG(HFSDBG_SYNCER | DBG_FUNC_START, obfuscate_addr(hfsmp));

    hfs_syncer_lock(hfsmp);

        while (ISSET(hfsmp->hfs_flags, HFS_RUN_SYNCER)
                   && timerisset(&hfsmp->hfs_sync_req_oldest)) {

                hfs_syncer_wait(hfsmp, &HFS_META_DELAY_TS);

                if (!ISSET(hfsmp->hfs_flags, HFS_RUN_SYNCER)
                        || !timerisset(&hfsmp->hfs_sync_req_oldest)) {
                        break;
                }

                /* Check to see whether we should flush now: either the oldest
                   is > HFS_MAX_META_DELAY or HFS_META_DELAY has elapsed since
                   the request and there are no pending writes. */

                microuptime(&now);
                uint64_t idle_time = vfs_idle_time(hfsmp->hfs_mp);

                if (!hfs_has_elapsed(&hfsmp->hfs_sync_req_oldest, &now,
                                                         HFS_MAX_META_DELAY)
                        && idle_time < HFS_META_DELAY) {
                        continue;
                }

                timerclear(&hfsmp->hfs_sync_req_oldest);

                hfs_syncer_unlock(hfsmp);

                KDBG(HFSDBG_SYNCER_TIMED | DBG_FUNC_START, obfuscate_addr(hfsmp));

                /*
                 * We intentionally do a synchronous flush (of the journal or entire volume) here.
                 * For journaled volumes, this means we wait until the metadata blocks are written
                 * to both the journal and their final locations (in the B-trees, etc.).
                 *
                 * This tends to avoid interleaving the metadata writes with other writes (for
                 * example, user data, or to the journal when a later transaction notices that
                 * an earlier transaction has finished its async writes, and then updates the
                 * journal start in the journal header).  Avoiding interleaving of writes is
                 * very good for performance on simple flash devices like SD cards, thumb drives;
                 * and on devices like floppies.  Since removable devices tend to be this kind of
                 * simple device, doing a synchronous flush actually improves performance in
                 * practice.
                 *
                 * NOTE: For non-journaled volumes, the call to hfs_sync will also cause dirty
                 * user data to be written.
                 */
                if (hfsmp->jnl) {
                        hfs_flush(hfsmp, HFS_FLUSH_JOURNAL_META);
                } else {
                        hfs_sync(hfsmp->hfs_mp, MNT_WAIT, vfs_context_current());
                }

                KDBG(HFSDBG_SYNCER_TIMED | DBG_FUNC_END);

                hfs_syncer_lock(hfsmp);
        } // while (...)

        hfsmp->hfs_syncer_thread = NULL;
        hfs_syncer_unlock(hfsmp);
        hfs_syncer_wakeup(hfsmp);

    /* BE CAREFUL WHAT YOU ADD HERE: at this point hfs_unmount is free
       to continue and therefore hfsmp might be invalid. */

    KDBG(HFSDBG_SYNCER | DBG_FUNC_END);
}

/*
 * Call into the allocator code and perform a full scan of the bitmap file.
 * 
 * This allows us to TRIM unallocated ranges if needed, and also to build up
 * an in-memory summary table of the state of the allocated blocks.
 */
void hfs_scan_blocks (struct hfsmount *hfsmp) {
        /*
         * Take the allocation file lock.  Journal transactions will block until
         * we're done here. 
         */
        
        int flags = hfs_systemfile_lock(hfsmp, SFL_BITMAP, HFS_EXCLUSIVE_LOCK);
        
        /* 
         * We serialize here with the HFS mount lock as we're mounting.
         * 
         * The mount can only proceed once this thread has acquired the bitmap 
         * lock, since we absolutely do not want someone else racing in and 
         * getting the bitmap lock, doing a read/write of the bitmap file, 
         * then us getting the bitmap lock.
         * 
         * To prevent this, the mount thread takes the HFS mount mutex, starts us 
         * up, then immediately msleeps on the scan_var variable in the mount 
         * point as a condition variable.  This serialization is safe since 
         * if we race in and try to proceed while they're still holding the lock, 
         * we'll block trying to acquire the global lock.  Since the mount thread 
         * acquires the HFS mutex before starting this function in a new thread, 
         * any lock acquisition on our part must be linearizably AFTER the mount thread's. 
         *
         * Note that the HFS mount mutex is always taken last, and always for only
         * a short time.  In this case, we just take it long enough to mark the
         * scan-in-flight bit.
         */
        (void) hfs_lock_mount (hfsmp);
        hfsmp->scan_var |= HFS_ALLOCATOR_SCAN_INFLIGHT;
        wakeup((caddr_t) &hfsmp->scan_var);
        hfs_unlock_mount (hfsmp);

        /* Initialize the summary table */
        if (hfs_init_summary (hfsmp)) {
                printf("hfs: could not initialize summary table for %s\n", hfsmp->vcbVN);
        }       

        /*
         * ScanUnmapBlocks assumes that the bitmap lock is held when you 
         * call the function. We don't care if there were any errors issuing unmaps.
         *
         * It will also attempt to build up the summary table for subsequent
         * allocator use, as configured.
         */
        (void) ScanUnmapBlocks(hfsmp);

        (void) hfs_lock_mount (hfsmp);
        hfsmp->scan_var &= ~HFS_ALLOCATOR_SCAN_INFLIGHT;
        hfsmp->scan_var |= HFS_ALLOCATOR_SCAN_COMPLETED;
        wakeup((caddr_t) &hfsmp->scan_var);
        hfs_unlock_mount (hfsmp);

        buf_invalidateblks(hfsmp->hfs_allocation_vp, 0, 0, 0);
        
        hfs_systemfile_unlock(hfsmp, flags);

}

static int hfs_root_unmounted_cleanly = 0;

SYSCTL_DECL(_vfs_generic);
HFS_SYSCTL(INT, _vfs_generic, OID_AUTO, root_unmounted_cleanly, CTLFLAG_RD, &hfs_root_unmounted_cleanly, 0, "Root filesystem was unmounted cleanly");

/*
 * Common code for mount and mountroot
 */
int
hfs_mountfs(struct vnode *devvp, struct mount *mp, struct hfs_mount_args *args,
            int journal_replay_only, vfs_context_t context)
{
        struct proc *p = vfs_context_proc(context);
        int retval = E_NONE;
        struct hfsmount *hfsmp = NULL;
        struct buf *bp;
        dev_t dev;
        HFSMasterDirectoryBlock *mdbp = NULL;
        int ronly;
#if QUOTA
        int i;
#endif
        int mntwrapper;
        kauth_cred_t cred;
        u_int64_t disksize;
        daddr64_t log_blkcnt;
        u_int32_t log_blksize;
        u_int32_t phys_blksize;
        u_int32_t minblksize;
        u_int32_t iswritable;
        daddr64_t mdb_offset;
        int isvirtual = 0;
        int isroot = !journal_replay_only && args == NULL;
        u_int32_t device_features = 0;
        int isssd;

        ronly = mp && 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 */
        if (mp)
                vfs_setlocklocal(mp);

        /* Get the logical block size (treated as physical block size everywhere) */
        if (VNOP_IOCTL(devvp, DKIOCGETBLOCKSIZE, (caddr_t)&log_blksize, 0, context)) {
                if (HFS_MOUNT_DEBUG) {
                        printf("hfs_mountfs: DKIOCGETBLOCKSIZE failed\n");
                }
                retval = ENXIO;
                goto error_exit;
        }
        if (log_blksize == 0 || log_blksize > 1024*1024*1024) {
                printf("hfs: logical block size 0x%x looks bad.  Not mounting.\n", log_blksize);
                retval = ENXIO;
                goto error_exit;
        }
        
        /* Get the physical block size. */
        retval = VNOP_IOCTL(devvp, DKIOCGETPHYSICALBLOCKSIZE, (caddr_t)&phys_blksize, 0, context);
        if (retval) {
                if ((retval != ENOTSUP) && (retval != ENOTTY)) {
                        if (HFS_MOUNT_DEBUG) {
                                printf("hfs_mountfs: DKIOCGETPHYSICALBLOCKSIZE failed\n");
                        }
                        retval = ENXIO;
                        goto error_exit;
                }
                /* If device does not support this ioctl, assume that physical 
                 * block size is same as logical block size 
                 */
                phys_blksize = log_blksize;
        }
        if (phys_blksize == 0 || phys_blksize > MAXBSIZE) {
                printf("hfs: physical block size 0x%x looks bad.  Not mounting.\n", phys_blksize);
                retval = ENXIO;
                goto error_exit;
        }

        /* Switch to 512 byte sectors (temporarily) */
        if (log_blksize > 512) {
                u_int32_t size512 = 512;

                if (VNOP_IOCTL(devvp, DKIOCSETBLOCKSIZE, (caddr_t)&size512, FWRITE, context)) {
                        if (HFS_MOUNT_DEBUG) {
                                printf("hfs_mountfs: DKIOCSETBLOCKSIZE failed \n");
                        }
                        retval = ENXIO;
                        goto error_exit;
                }
        }
        /* Get the number of 512 byte physical blocks. */
        if (VNOP_IOCTL(devvp, DKIOCGETBLOCKCOUNT, (caddr_t)&log_blkcnt, 0, context)) {
                /* resetting block size may fail if getting block count did */
                (void)VNOP_IOCTL(devvp, DKIOCSETBLOCKSIZE, (caddr_t)&log_blksize, FWRITE, context);
                if (HFS_MOUNT_DEBUG) {
                        printf("hfs_mountfs: DKIOCGETBLOCKCOUNT failed\n");
                }
                retval = ENXIO;
                goto error_exit;
        }
        /* Compute an accurate disk size (i.e. within 512 bytes) */
        disksize = (u_int64_t)log_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 the device size is not a multiple of 4K (8 * 512), then
         * switching the logical block size isn't going to help because
         * we will be unable to write the alternate volume header.
         * In this case, just leave the logical block size unchanged.
         */
        if (log_blkcnt > 0x000000007fffffff && (log_blkcnt & 7) == 0) {
                minblksize = log_blksize = 4096;
                if (phys_blksize < log_blksize)
                        phys_blksize = log_blksize;
        }
        
        /*
         * The cluster layer is not currently prepared to deal with a logical
         * block size larger than the system's page size.  (It can handle 
         * blocks per page, but not multiple pages per block.)  So limit the
         * logical block size to the page size.
         */
        if (log_blksize > PAGE_SIZE) {
                log_blksize = PAGE_SIZE;
        }

        /* Now switch to our preferred physical block size. */
        if (log_blksize > 512) {
                if (VNOP_IOCTL(devvp, DKIOCSETBLOCKSIZE, (caddr_t)&log_blksize, FWRITE, context)) {
                        if (HFS_MOUNT_DEBUG) { 
                                printf("hfs_mountfs: DKIOCSETBLOCKSIZE (2) failed\n");
                        }
                        retval = ENXIO;
                        goto error_exit;
                }
                /* Get the count of physical blocks. */
                if (VNOP_IOCTL(devvp, DKIOCGETBLOCKCOUNT, (caddr_t)&log_blkcnt, 0, context)) {
                        if (HFS_MOUNT_DEBUG) { 
                                printf("hfs_mountfs: DKIOCGETBLOCKCOUNT (2) failed\n");
                        }
                        retval = ENXIO;
                        goto error_exit;
                }
        }
        /*
         * At this point:
         *   minblksize is the minimum physical block size
         *   log_blksize has our preferred physical block size
         *   log_blkcnt has the total number of physical blocks
         */

        mdb_offset = (daddr64_t)HFS_PRI_SECTOR(log_blksize);
        if ((retval = (int)buf_meta_bread(devvp, 
                                HFS_PHYSBLK_ROUNDDOWN(mdb_offset, (phys_blksize/log_blksize)), 
                                phys_blksize, cred, &bp))) {
                if (HFS_MOUNT_DEBUG) {
                        printf("hfs_mountfs: buf_meta_bread failed with %d\n", retval);
                }
                goto error_exit;
        }
        mdbp = hfs_malloc(kMDBSize);
        bcopy((char *)buf_dataptr(bp) + HFS_PRI_OFFSET(phys_blksize), mdbp, kMDBSize);
        buf_brelse(bp);
        bp = NULL;

        hfsmp = hfs_mallocz(sizeof(struct hfsmount));

        hfs_chashinit_finish(hfsmp);
        
        /* Init the ID lookup hashtable */
        hfs_idhash_init (hfsmp);

        /*
         * See if the disk supports unmap (trim).
         *
         * NOTE: vfs_init_io_attributes has not been called yet, so we can't use the io_flags field
         * returned by vfs_ioattr.  We need to call VNOP_IOCTL ourselves.
         */
        if (VNOP_IOCTL(devvp, DKIOCGETFEATURES, (caddr_t)&device_features, 0, context) == 0) {
                if (device_features & DK_FEATURE_UNMAP) {
                        hfsmp->hfs_flags |= HFS_UNMAP;
                }

                if(device_features & DK_FEATURE_BARRIER)
                        hfsmp->hfs_flags |= HFS_FEATURE_BARRIER;
        }

        /* 
         * See if the disk is a solid state device, too.  We need this to decide what to do about 
         * hotfiles.
         */
        if (VNOP_IOCTL(devvp, DKIOCISSOLIDSTATE, (caddr_t)&isssd, 0, context) == 0) {
                if (isssd) {
                        hfsmp->hfs_flags |= HFS_SSD;
                }
        }

        /* See if the underlying device is Core Storage or not */
        dk_corestorage_info_t cs_info;
        memset(&cs_info, 0, sizeof(dk_corestorage_info_t));
        if (VNOP_IOCTL(devvp, DKIOCCORESTORAGE, (caddr_t)&cs_info, 0, context) == 0) {
                hfsmp->hfs_flags |= HFS_CS;
                if (isroot && (cs_info.flags & DK_CORESTORAGE_PIN_YOUR_METADATA)) {
                        hfsmp->hfs_flags |= HFS_CS_METADATA_PIN;
                }
                if (isroot && (cs_info.flags & DK_CORESTORAGE_ENABLE_HOTFILES)) {
                        hfsmp->hfs_flags |= HFS_CS_HOTFILE_PIN;
                        hfsmp->hfs_cs_hotfile_size = cs_info.hotfile_size;
                }
                if ((cs_info.flags & DK_CORESTORAGE_PIN_YOUR_SWAPFILE)) {
                        hfsmp->hfs_flags |= HFS_CS_SWAPFILE_PIN;

                        struct vfsioattr ioattr;
                        vfs_ioattr(mp, &ioattr);
                        ioattr.io_flags |= VFS_IOATTR_FLAGS_SWAPPIN_SUPPORTED;
                        ioattr.io_max_swappin_available = cs_info.swapfile_pinning;
                        vfs_setioattr(mp, &ioattr);
                }
        }

        /*
         *  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_spin_init(&hfsmp->vcbFreeExtLock, hfs_spinlock_group, hfs_lock_attr);

        if (mp)
                vfs_setfsprivate(mp, hfsmp);
        hfsmp->hfs_mp = mp;                     /* Make VFSTOHFS work */
        hfsmp->hfs_raw_dev = vnode_specrdev(devvp);
        hfsmp->hfs_devvp = devvp;
        vnode_ref(devvp);  /* Hold a ref on the device, dropped when hfsmp is freed. */
        hfsmp->hfs_logical_block_size = log_blksize;
        hfsmp->hfs_logical_block_count = log_blkcnt;
        hfsmp->hfs_logical_bytes = (uint64_t) log_blksize * (uint64_t) log_blkcnt;
        hfsmp->hfs_physical_block_size = phys_blksize;
        hfsmp->hfs_log_per_phys = (phys_blksize / log_blksize);
        hfsmp->hfs_flags |= HFS_WRITEABLE_MEDIA;
        if (ronly)
                hfsmp->hfs_flags |= HFS_READ_ONLY;
        if (mp && ((unsigned int)vfs_flags(mp)) & MNT_UNKNOWNPERMISSIONS)
                hfsmp->hfs_flags |= HFS_UNKNOWN_PERMS;

#if QUOTA
        for (i = 0; i < MAXQUOTAS; i++)
                dqfileinit(&hfsmp->hfs_qfiles[i]);
#endif

        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 (mp && ((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;
        }

        // Reservations
        rl_init(&hfsmp->hfs_reserved_ranges[0]);
        rl_init(&hfsmp->hfs_reserved_ranges[1]);

        // 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 CONFIG_HFS_STD 
                /* If only journal replay is requested, exit immediately */
                if (journal_replay_only) {
                        retval = 0;
                        goto error_exit;
                }

                /* On 10.6 and beyond, non read-only mounts for HFS standard vols get rejected */
                if (vfs_isrdwr(mp)) {
                        retval = EROFS;
                        goto error_exit;
                }

                printf("hfs_mountfs: Mounting HFS Standard volumes was deprecated in Mac OS 10.7 \n");

                /* Treat it as if it's read-only and not writeable */
                hfsmp->hfs_flags |= HFS_READ_ONLY;
                hfsmp->hfs_flags &= ~HFS_WRITEABLE_MEDIA;

                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 (log_blksize > kHFSBlockSize) {
                        log_blksize = kHFSBlockSize;
                        if (VNOP_IOCTL(devvp, DKIOCSETBLOCKSIZE, (caddr_t)&log_blksize, FWRITE, context)) {
                                retval = ENXIO;
                                goto error_exit;
                        }
                        if (VNOP_IOCTL(devvp, DKIOCGETBLOCKCOUNT, (caddr_t)&log_blkcnt, 0, context)) {
                                retval = ENXIO;
                                goto error_exit;
                        }
                        hfsmp->hfs_logical_block_size = log_blksize;
                        hfsmp->hfs_logical_block_count = log_blkcnt;
                        hfsmp->hfs_logical_bytes = (uint64_t) log_blksize * (uint64_t) log_blkcnt;
                        hfsmp->hfs_physical_block_size = log_blksize;
                        hfsmp->hfs_log_per_phys = 1;
                }
                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
                /* On platforms where HFS Standard is not supported, deny the mount altogether */
                retval = EINVAL;
                goto error_exit;
#endif

        } 
        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);

                        /* 
                         * Cooperative Fusion is not allowed on embedded HFS+ 
                         * filesystems (HFS+ inside HFS standard wrapper)
                         */
                        hfsmp->hfs_flags &= ~HFS_CS_METADATA_PIN;

                        /*
                         * 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 % log_blksize) != 0) {
                                printf("hfs_mountfs: embedded volume offset not"
                                    " a multiple of physical block size (%d);"
                                    " switching to 512\n", log_blksize);
                                log_blksize = 512;
                                if (VNOP_IOCTL(devvp, DKIOCSETBLOCKSIZE,
                                    (caddr_t)&log_blksize, FWRITE, context)) {

                                        if (HFS_MOUNT_DEBUG) { 
                                                printf("hfs_mountfs: DKIOCSETBLOCKSIZE (3) failed\n");
                                        }                               
                                        retval = ENXIO;
                                        goto error_exit;
                                }
                                if (VNOP_IOCTL(devvp, DKIOCGETBLOCKCOUNT,
                                    (caddr_t)&log_blkcnt, 0, context)) {
                                        if (HFS_MOUNT_DEBUG) { 
                                                printf("hfs_mountfs: DKIOCGETBLOCKCOUNT (3) failed\n");
                                        }
                                        retval = ENXIO;
                                        goto error_exit;
                                }
                                /* Note: relative block count adjustment */
                                hfsmp->hfs_logical_block_count *=
                                    hfsmp->hfs_logical_block_size / log_blksize;
                                
                                /* Update logical /physical block size */
                                hfsmp->hfs_logical_block_size = log_blksize;
                                hfsmp->hfs_physical_block_size = log_blksize;
                                
                                phys_blksize = log_blksize;
                                hfsmp->hfs_log_per_phys = 1;
                        }

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

                        hfsmp->hfs_logical_block_count = disksize / log_blksize;
        
                        hfsmp->hfs_logical_bytes = (uint64_t) hfsmp->hfs_logical_block_count * (uint64_t) hfsmp->hfs_logical_block_size;
                        
                        mdb_offset = (daddr64_t)((embeddedOffset / log_blksize) + HFS_PRI_SECTOR(log_blksize));

                        if (bp) {
                                buf_markinvalid(bp);
                                buf_brelse(bp);
                                bp = NULL;
                        }
                        retval = (int)buf_meta_bread(devvp, HFS_PHYSBLK_ROUNDDOWN(mdb_offset, hfsmp->hfs_log_per_phys),
                                        phys_blksize, cred, &bp);
                        if (retval) {
                                if (HFS_MOUNT_DEBUG) { 
                                        printf("hfs_mountfs: buf_meta_bread (2) failed with %d\n", retval);
                                }
                                goto error_exit;
                        }
                        bcopy((char *)buf_dataptr(bp) + HFS_PRI_OFFSET(phys_blksize), mdbp, 512);
                        buf_brelse(bp);
                        bp = NULL;
                        vhp = (HFSPlusVolumeHeader*) mdbp;

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

                retval = hfs_ValidateHFSPlusVolumeHeader(hfsmp, vhp);
                if (retval)
                        goto error_exit;

                /*
                 * If allocation block size is less than the physical block size,
                 * invalidate the buffer read in using native physical block size
                 * to ensure data consistency.
                 *
                 * HFS Plus reserves one allocation block for the Volume Header.
                 * If the physical size is larger, then when we read the volume header,
                 * we will also end up reading in the next allocation block(s).
                 * If those other allocation block(s) is/are modified, and then the volume
                 * header is modified, the write of the volume header's buffer will write
                 * out the old contents of the other allocation blocks.
                 *
                 * We assume that the physical block size is same as logical block size.
                 * The physical block size value is used to round down the offsets for
                 * reading and writing the primary and alternate volume headers.
                 *
                 * The same logic is also in hfs_MountHFSPlusVolume to ensure that
                 * hfs_mountfs, hfs_MountHFSPlusVolume and later are doing the I/Os
                 * using same block size.
                 */
                if (SWAP_BE32(vhp->blockSize) < hfsmp->hfs_physical_block_size) {
                        phys_blksize = hfsmp->hfs_logical_block_size;
                        hfsmp->hfs_physical_block_size = hfsmp->hfs_logical_block_size;
                        hfsmp->hfs_log_per_phys = 1;
                        // There should be one bp associated with devvp in buffer cache.
                        retval = buf_invalidateblks(devvp, 0, 0, 0);
                        if (retval)
                                goto error_exit;
                }

                if (isroot) {
                        hfs_root_unmounted_cleanly = ((SWAP_BE32(vhp->attributes) & kHFSVolumeUnmountedMask) != 0);
                }

                /*
                 * On inconsistent disks, do not allow read-write mount
                 * unless it is the boot volume being mounted.  We also
                 * always want to replay the journal if the journal_replay_only
                 * flag is set because that will (most likely) get the
                 * disk into a consistent state before fsck_hfs starts
                 * looking at it.
                 */
                if (!journal_replay_only
                        && !(vfs_flags(mp) & MNT_ROOTFS)
                        && (SWAP_BE32(vhp->attributes) & kHFSVolumeInconsistentMask)
                        && !(hfsmp->hfs_flags & HFS_READ_ONLY)) {
                        
                        if (HFS_MOUNT_DEBUG) { 
                                printf("hfs_mountfs: failed to mount non-root inconsistent disk\n");
                        }
                        retval = EINVAL;
                        goto error_exit;
                }


                // 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 ((retval = hfs_early_journal_init(hfsmp, vhp, args, embeddedOffset, mdb_offset, mdbp, cred)) == 0) {
                                if (mp)
                                        vfs_setflags(mp, (u_int64_t)((unsigned int)MNT_JOURNALED));
                        } else {
                                if (retval == EROFS) {
                                        // EROFS is a special error code that means the volume has an external
                                        // journal which we couldn't find.  in that case we do not want to
                                        // rewrite the volume header - we'll just refuse to mount the volume.
                                        if (HFS_MOUNT_DEBUG) { 
                                                printf("hfs_mountfs: hfs_early_journal_init indicated external jnl \n");
                                        }
                                        retval = EINVAL;
                                        goto error_exit;
                                }

                                // 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) {
                                        if (HFS_MOUNT_DEBUG) { 
                                                printf("hfs_mountfs: hfs_early_journal_init failed, setting to FSK \n");
                                        }

                                        HFSPlusVolumeHeader *jvhp;

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

                                    bp = NULL;
                                    retval = (int)buf_meta_bread(devvp, 
                                                    HFS_PHYSBLK_ROUNDDOWN(mdb_offset, hfsmp->hfs_log_per_phys), 
                                                    phys_blksize, cred, &bp);
                                    if (retval == 0) {
                                        jvhp = (HFSPlusVolumeHeader *)(buf_dataptr(bp) + HFS_PRI_OFFSET(phys_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 (mp && !(vfs_flags(mp) & MNT_ROOTFS)) {
                                        if (HFS_MOUNT_DEBUG) { 
                                                printf("hfs_mountfs: hfs_early_journal_init failed, erroring out \n");
                                        }
                                    retval = EINVAL;
                                    goto error_exit;
                                }
                        }
                }

                /* Either the journal is replayed successfully, or there 
                 * was nothing to replay, or no journal exists.  In any case,
                 * return success.
                 */
                if (journal_replay_only) {
                        retval = 0;
                        goto error_exit;
                }

#if CONFIG_HFS_STD
                (void) hfs_getconverter(0, &hfsmp->hfs_get_unicode, &hfsmp->hfs_get_hfsname);
#endif

                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) && (log_blksize > 512) && (log_blksize != minblksize)) {
                        printf("hfs_mountfs: could not use physical block size "
                                        "(%d) switching to 512\n", log_blksize);
                        log_blksize = 512;
                        if (VNOP_IOCTL(devvp, DKIOCSETBLOCKSIZE, (caddr_t)&log_blksize, FWRITE, context)) {
                                if (HFS_MOUNT_DEBUG) { 
                                        printf("hfs_mountfs: DKIOCSETBLOCKSIZE (4) failed \n");
                                }
                                retval = ENXIO;
                                goto error_exit;
                        }
                        if (VNOP_IOCTL(devvp, DKIOCGETBLOCKCOUNT, (caddr_t)&log_blkcnt, 0, context)) {
                                if (HFS_MOUNT_DEBUG) { 
                                        printf("hfs_mountfs: DKIOCGETBLOCKCOUNT (4) failed \n");
                                }
                                retval = ENXIO;
                                goto error_exit;
                        }
                        set_fsblocksize(devvp);
                        /* Note: relative block count adjustment (in case this is an embedded volume). */
                        hfsmp->hfs_logical_block_count *= hfsmp->hfs_logical_block_size / log_blksize;
                        hfsmp->hfs_logical_block_size = log_blksize;
                        hfsmp->hfs_log_per_phys = hfsmp->hfs_physical_block_size / log_blksize;
        
                        hfsmp->hfs_logical_bytes = (uint64_t) hfsmp->hfs_logical_block_count * (uint64_t) hfsmp->hfs_logical_block_size;

                        if (hfsmp->jnl && hfsmp->jvp == devvp) {
                            // 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, (u_int64_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) {
                                                if (HFS_MOUNT_DEBUG) { 
                                                        printf("hfs_mountfs: hfs_early_journal_init (2) resetting.. \n");
                                                }
                                        HFSPlusVolumeHeader *jvhp;

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

                                                bp = NULL;
                                        retval = (int)buf_meta_bread(devvp, HFS_PHYSBLK_ROUNDDOWN(mdb_offset, hfsmp->hfs_log_per_phys), 
                                                        phys_blksize, cred, &bp);
                                        if (retval == 0) {
                                                        jvhp = (HFSPlusVolumeHeader *)(buf_dataptr(bp) + HFS_PRI_OFFSET(phys_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)) {
                                                if (HFS_MOUNT_DEBUG) { 
                                                        printf("hfs_mountfs: hfs_early_journal_init (2) failed \n");
                                                }
                                        retval = EINVAL;
                                        goto error_exit;
                                        }
                                }
                        }

                        /* Try again with a smaller block size... */
                        retval = hfs_MountHFSPlusVolume(hfsmp, vhp, embeddedOffset, disksize, p, args, cred);
                        if (retval && HFS_MOUNT_DEBUG) {
                                printf("hfs_MountHFSPlusVolume (late) returned %d\n",retval); 
                        }
                }
#if CONFIG_HFS_STD
                if (retval)
                        (void) hfs_relconverter(0);
#endif
        }

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

        if ( retval ) {
                if (HFS_MOUNT_DEBUG) { 
                        printf("hfs_mountfs: encountered failure %d \n", retval);
                }
                goto error_exit;
        }

        struct vfsstatfs *vsfs = vfs_statfs(mp);
        vsfs->f_fsid.val[0] = dev;
        vsfs->f_fsid.val[1] = vfs_typenum(mp);

        vfs_setmaxsymlen(mp, 0);

#if CONFIG_HFS_STD
        if (ISSET(hfsmp->hfs_flags, HFS_STANDARD)) {
                /* HFS standard doesn't support extended readdir! */
                mount_set_noreaddirext (mp);
        }
#endif

        if (args) {
                /*
                 * Set the free space warning levels for a non-root volume:
                 *
                 * Set the "danger" limit to 1% of the volume size or 100MB, whichever
                 * is less.  Set the "warning" limit to 2% of the volume size or 150MB,
                 * whichever is less.  And last, set the "desired" freespace level to
                 * to 3% of the volume size or 200MB, whichever is less.
                 */
                hfsmp->hfs_freespace_notify_dangerlimit =
                        MIN(HFS_VERYLOWDISKTRIGGERLEVEL / HFSTOVCB(hfsmp)->blockSize,
                                (HFSTOVCB(hfsmp)->totalBlocks / 100) * HFS_VERYLOWDISKTRIGGERFRACTION);
                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 "danger" limit to 5% of the volume size or 512MB, whichever
                 * is less.  Set the "warning" limit to 10% of the volume size or 1GB,
                 * whichever is less.  And last, set the "desired" freespace level to
                 * to 11% of the volume size or 1.25GB, whichever is less.
                 *
                 * NOTE: While those are the default limits, KernelEventAgent (as of 3/2016)
                 * will unilaterally override these to the following on OSX only:
                 *    Danger: 3GB
                 *    Warning: Min (2% of root volume, 10GB), with a floor of 10GB
                 *    Desired: Warning Threshold + 1.5GB  
                 */
                hfsmp->hfs_freespace_notify_dangerlimit =
                        MIN(HFS_ROOTVERYLOWDISKTRIGGERLEVEL / HFSTOVCB(hfsmp)->blockSize,
                                (HFSTOVCB(hfsmp)->totalBlocks / 100) * HFS_ROOTVERYLOWDISKTRIGGERFRACTION);
                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);
        };
        
        /* Check if the file system exists on virtual device, like disk image */
        if (VNOP_IOCTL(devvp, DKIOCISVIRTUAL, (caddr_t)&isvirtual, 0, context) == 0) {
                if (isvirtual) {
                        hfsmp->hfs_flags |= HFS_VIRTUAL_DEVICE;
                }
        }

        if (!isroot
                && !ISSET(hfsmp->hfs_flags, HFS_VIRTUAL_DEVICE)
                && hfs_is_ejectable(vfs_statfs(mp)->f_mntfromname)) {
                SET(hfsmp->hfs_flags, HFS_RUN_SYNCER);
        }

        const char *dev_name = (hfsmp->hfs_devvp
                                                        ? vnode_getname_printable(hfsmp->hfs_devvp) : NULL);

        printf("hfs: mounted %s on device %s\n",
                   (hfsmp->vcbVN[0] ? (const char*) hfsmp->vcbVN : "unknown"),
                   dev_name ?: "unknown device");

        if (dev_name)
                vnode_putname_printable(dev_name);

        /*
         * 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, HFS_FVH_WAIT);
        }
        hfs_free(mdbp, kMDBSize);
        return (0);

error_exit:
        if (bp)
                buf_brelse(bp);

        hfs_free(mdbp, kMDBSize);

        hfs_close_jvp(hfsmp);

        if (hfsmp) {
                if (hfsmp->hfs_devvp) {
                        vnode_rele(hfsmp->hfs_devvp);
                }
                hfs_locks_destroy(hfsmp);
                hfs_delete_chash(hfsmp);
                hfs_idhash_destroy (hfsmp);

                hfs_free(hfsmp, sizeof(*hfsmp));
                if (mp)
                        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
 */
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;
        }

        const char *dev_name = (hfsmp->hfs_devvp
                                                        ? vnode_getname_printable(hfsmp->hfs_devvp) : NULL);

        printf("hfs: unmount initiated on %s on device %s\n",
                   (hfsmp->vcbVN[0] ? (const char*) hfsmp->vcbVN : "unknown"),
                   dev_name ?: "unknown device");

        if (dev_name)
                vnode_putname_printable(dev_name);

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

        if (hfsmp->hfs_flags & HFS_METADATA_ZONE)
                (void) hfs_recording_suspend(hfsmp);
    
        hfs_syncer_free(hfsmp);
    
        if (hfsmp->hfs_flags & HFS_SUMMARY_TABLE) {
                if (hfsmp->hfs_summary_table) {
                        int err = 0;
                        /* 
                         * Take the bitmap lock to serialize against a concurrent bitmap scan still in progress 
                         */
                        if (hfsmp->hfs_allocation_vp) {
                                err = hfs_lock (VTOC(hfsmp->hfs_allocation_vp), HFS_EXCLUSIVE_LOCK, HFS_LOCK_DEFAULT);
                        }
                        hfs_free(hfsmp->hfs_summary_table, hfsmp->hfs_summary_bytes);
                        hfsmp->hfs_summary_table = NULL;
                        hfsmp->hfs_flags &= ~HFS_SUMMARY_TABLE;
                        
                        if (err == 0 && hfsmp->hfs_allocation_vp){
                                hfs_unlock (VTOC(hfsmp->hfs_allocation_vp));
                        }

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

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

                if (hfsmp->hfs_attribute_vp) {
                        (void) hfs_lock(VTOC(hfsmp->hfs_attribute_vp), HFS_EXCLUSIVE_LOCK, HFS_LOCK_DEFAULT);
                        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, HFS_LOCK_DEFAULT);
                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, HFS_LOCK_DEFAULT);
                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, HFS_LOCK_DEFAULT);
                        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 runtime corruption was detected, indicate that the volume
                 * was not unmounted cleanly.
                 */
                if (hfsmp->vcbAtrb & kHFSVolumeInconsistentMask) {
                        HFSTOVCB(hfsmp)->vcbAtrb &= ~kHFSVolumeUnmountedMask;
                } else {
                        HFSTOVCB(hfsmp)->vcbAtrb |= kHFSVolumeUnmountedMask;
                }

                if (hfsmp->hfs_flags & HFS_HAS_SPARSE_DEVICE) {
                        int i;
                        u_int32_t min_start = hfsmp->totalBlocks;
                        
                        // set the nextAllocation pointer to the smallest free block number
                        // we've seen so on the next mount we won't rescan unnecessarily
                        lck_spin_lock(&hfsmp->vcbFreeExtLock);
                        for(i=0; i < (int)hfsmp->vcbFreeExtCnt; i++) {
                                if (hfsmp->vcbFreeExt[i].startBlock < min_start) {
                                        min_start = hfsmp->vcbFreeExt[i].startBlock;
                                }
                        }
                        lck_spin_unlock(&hfsmp->vcbFreeExtLock);
                        if (min_start < hfsmp->nextAllocation) {
                                hfsmp->nextAllocation = min_start;
                        }
                }

                retval = hfs_flushvolumeheader(hfsmp, HFS_FVH_WAIT);
                if (retval) {
                        HFSTOVCB(hfsmp)->vcbAtrb &= ~kHFSVolumeUnmountedMask;
                        if (!force)
                                goto err_exit;  /* could not flush everything */
                }

                if (started_tr) {
                    hfs_end_transaction(hfsmp);
                    started_tr = 0;
                }
        }

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

#if CONFIG_HFS_STD
        if (HFSTOVCB(hfsmp)->vcbSigWord == kHFSSigWord) {
                (void) hfs_relconverter(hfsmp->hfs_encoding);
        }
#endif

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

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

        hfs_close_jvp(hfsmp);

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

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

                hfsmp->hfs_flags &= ~HFS_HAS_SPARSE_DEVICE;
                tmpvp = hfsmp->hfs_backingvp;
                hfsmp->hfs_backingvp = NULLVP;
                vnode_rele(tmpvp);
        }
#endif /* HFS_SPARSE_DEV */

        vnode_rele(hfsmp->hfs_devvp);

        hfs_locks_destroy(hfsmp);
        hfs_delete_chash(hfsmp);
        hfs_idhash_destroy(hfsmp);

        hfs_assert(TAILQ_EMPTY(&hfsmp->hfs_reserved_ranges[HFS_TENTATIVE_BLOCKS])
                   && TAILQ_EMPTY(&hfsmp->hfs_reserved_ranges[HFS_LOCKED_BLOCKS]));
        hfs_assert(!hfsmp->lockedBlocks);

        hfs_free(hfsmp, sizeof(*hfsmp));

#if HFS_LEAK_DEBUG
        if (OSDecrementAtomic(&hfs_active_mounts) == 1) {
                if (hfs_dump_allocations())
                        Debugger(NULL);
                else {
                        printf("hfs: last unmount and nothing was leaked!\n");
                        msleep(hfs_unmount, NULL, PINOD, "hfs_unmount",
                                   &(struct timespec){ 5, 0 });
                }
        }
#endif

        return (0);

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


/*
 * Return the root of a filesystem.
 */
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, 0);
}


/*
 * Do operations associated with quotas
 */
#if !QUOTA
static int
hfs_quotactl(__unused struct mount *mp, __unused int cmds, __unused uid_t uid, __unused caddr_t datap, __unused vfs_context_t context)
{
        return (ENOTSUP);
}
#else
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 (uid == ~0U)
                uid = kauth_cred_getuid(vfs_context_ucred(context));
        cmd = cmds >> SUBCMDSHIFT;

        switch (cmd) {
        case Q_SYNC:
        case Q_QUOTASTAT:
                break;
        case Q_GETQUOTA:
                if (uid == kauth_cred_getuid(vfs_context_ucred(context)))
                        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.
 */
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_int16_t subtype = 0;

        sbp->f_bsize = (u_int32_t)vcb->blockSize;
        sbp->f_iosize = (size_t)cluster_max_io_size(mp, 0);
        sbp->f_blocks = (u_int64_t)((u_int32_t)vcb->totalBlocks);
        sbp->f_bfree = (u_int64_t)((u_int32_t )hfs_freeblks(hfsmp, 0));
        sbp->f_bavail = (u_int64_t)((u_int32_t )hfs_freeblks(hfsmp, 1));
        sbp->f_files = (u_int64_t)HFS_MAX_FILES;
        sbp->f_ffree = (u_int64_t)hfs_free_cnids(hfsmp);

        /*
         * 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) == 0) {
                /* HFS+ & variants */
                if (hfsmp->jnl) {
                        subtype |= HFS_SUBTYPE_JOURNALED;
                }
                if (hfsmp->hfs_flags & HFS_CASE_SENSITIVE) {
                        subtype |= HFS_SUBTYPE_CASESENSITIVE;
                }
        }
#if CONFIG_HFS_STD
        else {
                /* HFS standard */
                subtype = HFS_SUBTYPE_STANDARDHFS;
        } 
#endif
        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.
//
void
hfs_sync_metadata(void *arg)
{
        struct mount *mp = (struct mount *)arg;
        struct hfsmount *hfsmp;
        ExtendedVCB *vcb;
        buf_t   bp;
        int  retval;
        daddr64_t priIDSector;
        hfsmp = VFSTOHFS(mp);
        vcb = HFSTOVCB(hfsmp);

        // now make sure the super block is flushed
        priIDSector = (daddr64_t)((vcb->hfsPlusIOPosOffset / hfsmp->hfs_logical_block_size) +
                                  HFS_PRI_SECTOR(hfsmp->hfs_logical_block_size));

        retval = (int)buf_meta_bread(hfsmp->hfs_devvp, 
                        HFS_PHYSBLK_ROUNDDOWN(priIDSector, hfsmp->hfs_log_per_phys),
                        hfsmp->hfs_physical_block_size, NOCRED, &bp);
        if ((retval != 0 ) && (retval != ENXIO)) {
                printf("hfs_sync_metadata: can't read volume header at %d! (retval 0x%x)\n",
                       (int)priIDSector, retval);
        }

        if (retval == 0 && ((buf_flags(bp) & (B_DELWRI | B_LOCKED)) == B_DELWRI)) {
            buf_bwrite(bp);
        } else if (bp) {
            buf_brelse(bp);
        }
        
        /* Note that these I/Os bypass the journal (no calls to journal_start_modify_block) */

        // 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_partition_avh_sector) {
                retval = (int)buf_meta_bread(hfsmp->hfs_devvp, 
                                HFS_PHYSBLK_ROUNDDOWN(hfsmp->hfs_partition_avh_sector, hfsmp->hfs_log_per_phys),
                                hfsmp->hfs_physical_block_size, NOCRED, &bp);
                if (retval == 0 && ((buf_flags(bp) & (B_DELWRI | B_LOCKED)) == B_DELWRI)) {
                    /* 
                         * note this I/O can fail if the partition shrank behind our backs! 
                         * So failure should be OK here.
                         */
                        buf_bwrite(bp);
                } else if (bp) {
                    buf_brelse(bp);
                }
        }

        /* Is the FS's idea of the AVH different than the partition ? */
        if ((hfsmp->hfs_fs_avh_sector) && (hfsmp->hfs_partition_avh_sector != hfsmp->hfs_fs_avh_sector)) {
                retval = (int)buf_meta_bread(hfsmp->hfs_devvp, 
                                HFS_PHYSBLK_ROUNDDOWN(hfsmp->hfs_fs_avh_sector, hfsmp->hfs_log_per_phys),
                                hfsmp->hfs_physical_block_size, 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;
        int                       atime_only_syncs;
        time_t            sync_start_time;
};


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

        args = (struct hfs_sync_cargs *)cargs;

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

        hfs_dirty_t dirty_state = hfs_is_dirty(cp);

        bool sync = dirty_state == HFS_DIRTY || vnode_hasdirtyblks(vp);

        if (!sync && dirty_state == HFS_DIRTY_ATIME
                && args->atime_only_syncs < 256) {
                // We only update if the atime changed more than 60s ago
                if (args->sync_start_time - cp->c_attr.ca_atime > 60) {
                        sync = true;
                        ++args->atime_only_syncs;
                }
        }

        if (sync) {
                error = hfs_fsync(vp, args->waitfor, 0, args->p);

                if (error)
                        args->error = error;
        } else if (cp->c_touch_acctime)
                hfs_touchtimes(VTOHFS(vp), cp);

        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'.
 */
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;

        hfsmp = VFSTOHFS(mp);

        // Back off if hfs_changefs or a freeze is underway
        hfs_lock_mount(hfsmp);
        if ((hfsmp->hfs_flags & HFS_IN_CHANGEFS)
            || hfsmp->hfs_freeze_state != HFS_THAWED) {
                hfs_unlock_mount(hfsmp);
                return 0;
        }

        if (hfsmp->hfs_flags & HFS_READ_ONLY) {
                hfs_unlock_mount(hfsmp);
                return (EROFS);
        }

        ++hfsmp->hfs_syncers;
        hfs_unlock_mount(hfsmp);

        args.cred = kauth_cred_get();
        args.waitfor = waitfor;
        args.p = p;
        args.error = 0;
        args.atime_only_syncs = 0;

        struct timeval tv;
        microtime(&tv);

        args.sync_start_time = tv.tv_sec;

        /*
         * 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, HFS_LOCK_DEFAULT);
                cp = VTOC(btvp);

                if (!hfs_is_dirty(cp) && !vnode_hasdirtyblks(btvp)) {
                        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);
        };


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

#if QUOTA
        hfs_qsync(mp);
#endif /* QUOTA */

        hfs_hotfilesync(hfsmp, vfs_context_kernel());

        /*
         * Write back modified superblock.
         */
        if (IsVCBDirty(vcb)) {
                error = hfs_flushvolumeheader(hfsmp, waitfor == MNT_WAIT ? HFS_FVH_WAIT : 0);
                if (error)
                        allerror = error;
        }

        if (hfsmp->jnl) {
            hfs_flush(hfsmp, HFS_FLUSH_JOURNAL);
        }

        hfs_lock_mount(hfsmp);
        boolean_t wake = (!--hfsmp->hfs_syncers
                                          && hfsmp->hfs_freeze_state == HFS_WANT_TO_FREEZE);
        hfs_unlock_mount(hfsmp);
        if (wake)
                wakeup(&hfsmp->hfs_freeze_state);

        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, __unused vfs_context_t context)
{
        struct hfsfid *hfsfhp;
        struct vnode *nvp;
        int result;

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

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

        result = hfs_vget(VFSTOHFS(mp), ntohl(hfsfhp->hfsfid_cnid), &nvp, 0, 0);
        if (result) {
                if (result == ENOENT)
                        result = ESTALE;
                return result;
        }

        /* 
         * We used to use the create time as the gen id of the file handle,
         * but it is not static enough because it can change at any point 
         * via system calls.  We still don't have another volume ID or other
         * unique identifier to use for a generation ID across reboots that
         * persists until the file is removed.  Using only the CNID exposes
         * us to the potential wrap-around case, but as of 2/2008, it would take
         * over 2 months to wrap around if the machine did nothing but allocate
         * CNIDs.  Using some kind of wrap counter would only be effective if
         * each file had the wrap counter associated with it.  For now, 
         * we use only the CNID to identify the file as it's good enough.
         */      

        *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, __unused 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;
        /* only the CNID is used to identify the file now */
        hfsfhp->hfsfid_cnid = htonl(cp->c_fileid);
        hfsfhp->hfsfid_gen = htonl(cp->c_fileid);
        *fhlenp = sizeof(struct hfsfid);
        
        return (0);
}


/*
 * Initialize HFS filesystems, done only once per boot.
 *
 * HFS is not a kext-based file system.  This makes it difficult to find 
 * out when the last HFS file system was unmounted and call hfs_uninit() 
 * to deallocate data structures allocated in hfs_init().  Therefore we 
 * never deallocate memory allocated by lock attribute and group initializations 
 * in this function.
 */
static int
hfs_init(__unused struct vfsconf *vfsp)
{
        static int done = 0;

        if (done)
                return (0);
        done = 1;
        hfs_chashinit();

        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);
        hfs_spinlock_group = lck_grp_alloc_init("hfs-spinlock", hfs_group_attr);
        
#if HFS_COMPRESSION
        decmpfs_init();
#endif

        journal_init();

        return (0);
}


/*
 * Destroy all locks, mutexes and spinlocks in hfsmp on unmount or failed mount
 */ 
static void 
hfs_locks_destroy(struct hfsmount *hfsmp)
{

        lck_mtx_destroy(&hfsmp->hfs_mutex, hfs_mutex_group);
        lck_mtx_destroy(&hfsmp->hfc_mutex, hfs_mutex_group);
        lck_rw_destroy(&hfsmp->hfs_global_lock, hfs_rwlock_group);
        lck_spin_destroy(&hfsmp->vcbFreeExtLock, hfs_spinlock_group);

        return;
}


static int
hfs_getmountpoint(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 (strncmp(fstypename, "hfs", sizeof(fstypename)) != 0)
                return (EINVAL);

        hfsmp = VTOHFS(vp);

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

        *hfsmpp = hfsmp;

        return (0);
}

// Replace user-space value
static errno_t ureplace(user_addr_t oldp, size_t *oldlenp,
                                                user_addr_t newp, size_t newlen,
                                                void *data, size_t len)
{
        errno_t error;
        if (!oldlenp)
                return EFAULT;
        if (oldp && *oldlenp < len)
                return ENOMEM;
        if (newp && newlen != len)
                return EINVAL;
        *oldlenp = len;
        if (oldp) {
                error = copyout(data, oldp, len);
                if (error)
                        return error;
        }
        return newp ? copyin(newp, data, len) : 0;
}

#define UREPLACE(oldp, oldlenp, newp, newlenp, v)       \
        ureplace(oldp, oldlenp, newp, newlenp, &v, sizeof(v))

static hfsmount_t *hfs_mount_from_cwd(vfs_context_t ctx)
{
        vnode_t vp = vfs_context_cwd(ctx);

        if (!vp)
                return NULL;

        /*
         * We could use vnode_tag, but it is probably more future proof to
         * compare fstypename.
         */
        char fstypename[MFSNAMELEN];
        vnode_vfsname(vp, fstypename);

        if (strcmp(fstypename, "hfs"))
                return NULL;

        return VTOHFS(vp);
}

/*
 * HFS filesystem related variables.
 */
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)
{
#if !TARGET_OS_EMBEDDED
        struct proc *p = vfs_context_proc(context);
#endif
        int error;
        struct hfsmount *hfsmp;

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

#if !TARGET_OS_EMBEDDED
        if (name[0] == HFS_ENCODINGBIAS) {
                int bias;

                bias = hfs_getencodingbias();

                error = UREPLACE(oldp, oldlenp, newp, newlen, bias);
                if (error || !newp)
                        return error;

                hfs_setencodingbias(bias);

                return 0;
        } else
#endif
        if (name[0] == HFS_EXTEND_FS) {
                u_int64_t  newsize = 0;
                vnode_t vp = vfs_context_cwd(context);

                if (newp == USER_ADDR_NULL || vp == NULLVP
                        || newlen != sizeof(quad_t) || !oldlenp)
                        return EINVAL;
                if ((error = hfs_getmountpoint(vp, &hfsmp)))
                        return (error);

                /* Start with the 'size' set to the current number of bytes in the filesystem */
                newsize = ((uint64_t)hfsmp->totalBlocks) * ((uint64_t)hfsmp->blockSize);

                error = UREPLACE(oldp, oldlenp, newp, newlen, newsize);
                if (error)
                        return error;

                return hfs_extendfs(hfsmp, newsize, context);
        } else if (name[0] == HFS_ENABLE_JOURNALING) {
                // make the file system journaled...
                vnode_t jvp;
                ExtendedVCB *vcb;
                struct cat_attr jnl_attr;
            struct cat_attr     jinfo_attr;
                struct cat_fork jnl_fork;
                struct cat_fork jinfo_fork;
                buf_t jib_buf;
                uint64_t jib_blkno;
                uint32_t tmpblkno;
                uint64_t journal_byte_offset;
                uint64_t journal_size;
                vnode_t jib_vp = NULLVP;
                struct JournalInfoBlock local_jib;
                int err = 0;
                void *jnl = NULL;
                int lockflags;

                /* Only root can enable journaling */
                if (!kauth_cred_issuser(kauth_cred_get())) {
                        return (EPERM);
                }
                if (namelen != 4)
                        return EINVAL;
                hfsmp = hfs_mount_from_cwd(context);
                if (!hfsmp)
                        return EINVAL;

                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 %s is already journaled!\n", hfsmp->vcbVN);
                    return EAGAIN;
                }
                vcb = HFSTOVCB(hfsmp);

                /* Set up local copies of the initialization info */
                tmpblkno = (uint32_t) name[1];
                jib_blkno = (uint64_t) tmpblkno;
                journal_byte_offset = (uint64_t) name[2];
                journal_byte_offset *= hfsmp->blockSize;
                journal_byte_offset += hfsmp->hfsPlusIOPosOffset;
                journal_size = (uint64_t)((unsigned)name[3]);

                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;
                }

                /*
                 * At this point, we have a copy of the metadata that lives in the catalog for the
                 * journal info block.  Compare that the journal info block's single extent matches
                 * that which was passed into this sysctl.  
                 *
                 * If it is different, deny the journal enable call.
                 */
                if (jinfo_fork.cf_blocks > 1) {
                        /* too many blocks */
                        return EINVAL;
                }

                if (jinfo_fork.cf_extents[0].startBlock != jib_blkno) {
                        /* Wrong block */
                        return EINVAL;
                }

                /*   
                 * We want to immediately purge the vnode for the JIB.
                 * 
                 * Because it was written to from userland, there's probably 
                 * a vnode somewhere in the vnode cache (possibly with UBC backed blocks). 
                 * So we bring the vnode into core, then immediately do whatever 
                 * we can to flush/vclean it out.  This is because those blocks will be 
                 * interpreted as user data, which may be treated separately on some platforms
                 * than metadata.  If the vnode is gone, then there cannot be backing blocks
                 * in the UBC.
                 */
                if (hfs_vget (hfsmp, jinfo_attr.ca_fileid, &jib_vp, 1, 0)) {
                        return EINVAL;
                } 
                /*
                 * Now we have a vnode for the JIB. recycle it. Because we hold an iocount
                 * on the vnode, we'll just mark it for termination when the last iocount
                 * (hopefully ours), is dropped.
                 */
                vnode_recycle (jib_vp);
                err = vnode_put (jib_vp);
                if (err) {
                        return EINVAL;  
                }

                /* Initialize the local copy of the JIB (just like hfs.util) */
                memset (&local_jib, 'Z', sizeof(struct JournalInfoBlock));
                local_jib.flags = SWAP_BE32(kJIJournalInFSMask);
                /* Note that the JIB's offset is in bytes */
                local_jib.offset = SWAP_BE64(journal_byte_offset);
                local_jib.size = SWAP_BE64(journal_size);  

                /* 
                 * Now write out the local JIB.  This essentially overwrites the userland
                 * copy of the JIB.  Read it as BLK_META to treat it as a metadata read/write.
                 */
                jib_buf = buf_getblk (hfsmp->hfs_devvp, 
                                jib_blkno * (hfsmp->blockSize / hfsmp->hfs_logical_block_size), 
                                hfsmp->blockSize, 0, 0, BLK_META);
                char* buf_ptr = (char*) buf_dataptr (jib_buf);

                /* Zero out the portion of the block that won't contain JIB data */
                memset (buf_ptr, 0, hfsmp->blockSize);

                bcopy(&local_jib, buf_ptr, sizeof(local_jib));
                if (buf_bwrite (jib_buf)) {
                        return EIO;
                }

                /* Force a flush track cache */
                hfs_flush(hfsmp, HFS_FLUSH_CACHE);

                /* Now proceed with full volume sync */
                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]);

                //
                // XXXdbg - note that currently (Sept, 08) hfs_util does not support
                //          enabling the journal on a separate device so it is safe
                //          to just copy hfs_devvp here.  If hfs_util gets the ability
                //          to dynamically enable the journal on a separate device then
                //          we will have to do the same thing as hfs_early_journal_init()
                //          to locate and open the journal device.
                //
                jvp = hfsmp->hfs_devvp;
                jnl = journal_create(jvp, journal_byte_offset, journal_size, 
                                                         hfsmp->hfs_devvp,
                                                         hfsmp->hfs_logical_block_size,
                                                         0,
                                                         0,
                                                         hfs_sync_metadata, hfsmp->hfs_mp,
                                                         hfsmp->hfs_mp);

                /*
                 * Set up the trim callback function so that we can add
                 * recently freed extents to the free extent cache once
                 * the transaction that freed them is written to the
                 * journal on disk.
                 */
                if (jnl)
                        journal_trim_set_callback(jnl, hfs_trim_callback, hfsmp);

                if (jnl == NULL) {
                        printf("hfs: FAILED to create the journal!\n");
                        return EIO;
                } 

                hfs_lock_global (hfsmp, HFS_EXCLUSIVE_LOCK);

                /*
                 * Flush all dirty metadata buffers.
                 */
                buf_flushdirtyblks(hfsmp->hfs_devvp, TRUE, 0, "hfs_sysctl");
                buf_flushdirtyblks(hfsmp->hfs_extents_vp, TRUE, 0, "hfs_sysctl");
                buf_flushdirtyblks(hfsmp->hfs_catalog_vp, TRUE, 0, "hfs_sysctl");
                buf_flushdirtyblks(hfsmp->hfs_allocation_vp, TRUE, 0, "hfs_sysctl");
                if (hfsmp->hfs_attribute_vp)
                        buf_flushdirtyblks(hfsmp->hfs_attribute_vp, TRUE, 0, "hfs_sysctl");

                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, (u_int64_t)((unsigned int)MNT_JOURNALED));

                hfs_unlock_global (hfsmp);
                hfs_flushvolumeheader(hfsmp, HFS_FVH_WAIT | HFS_FVH_WRITE_ALT);

                {
                        fsid_t fsid;
                
                        fsid.val[0] = (int32_t)hfsmp->hfs_raw_dev;
                        fsid.val[1] = (int32_t)vfs_typenum(HFSTOVFS(hfsmp));
                        vfs_event_signal(&fsid, VQ_UPDATE, (intptr_t)NULL);
                }
                return 0;
        } else if (name[0] == HFS_DISABLE_JOURNALING) {
                // clear the journaling bit

                /* Only root can disable journaling */
                if (!kauth_cred_issuser(kauth_cred_get())) {
                        return (EPERM);
                }

                hfsmp = hfs_mount_from_cwd(context);
                if (!hfsmp)
                        return EINVAL;

                /* 
                 * Disabling journaling is disallowed on volumes with directory hard links
                 * because we have not tested the relevant code path.
                 */  
                if (hfsmp->hfs_private_attr[DIR_HARDLINKS].ca_entries != 0){
                        printf("hfs: cannot disable journaling on volumes with directory hardlinks\n");
                        return EPERM;
                }

                printf("hfs: disabling journaling for %s\n", hfsmp->vcbVN);

                hfs_lock_global (hfsmp, HFS_EXCLUSIVE_LOCK);

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

                hfs_close_jvp(hfsmp);
                vfs_clearflags(hfsmp->hfs_mp, (u_int64_t)((unsigned int)MNT_JOURNALED));
                hfsmp->jnl_start        = 0;
                hfsmp->hfs_jnlinfoblkid = 0;
                hfsmp->hfs_jnlfileid    = 0;
                
                HFSTOVCB(hfsmp)->vcbAtrb &= ~kHFSVolumeJournaledMask;
                
                hfs_unlock_global (hfsmp);

                hfs_flushvolumeheader(hfsmp, HFS_FVH_WAIT | HFS_FVH_WRITE_ALT);

                {
                        fsid_t fsid;
                
                        fsid.val[0] = (int32_t)hfsmp->hfs_raw_dev;
                        fsid.val[1] = (int32_t)vfs_typenum(HFSTOVFS(hfsmp));
                        vfs_event_signal(&fsid, VQ_UPDATE, (intptr_t)NULL);
                }
                return 0;
        } else if (name[0] == VFS_CTL_QUERY) {
#if TARGET_OS_EMBEDDED
                return EPERM;
#else
        struct sysctl_req *req;
        union union_vfsidctl vc;
        struct mount *mp;
            struct vfsquery vq;
        
                req = CAST_DOWN(struct sysctl_req *, oldp);     /* we're new style vfs sysctl. */
                if (req == NULL) {
                        return EFAULT;
                }
        
        error = SYSCTL_IN(req, &vc, proc_is64bit(p)? sizeof(vc.vc64):sizeof(vc.vc32));
                if (error) return (error);

                mp = vfs_getvfs(&vc.vc32.vc_fsid); /* works for 32 and 64 */
        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));;
#endif
        } else if (name[0] == HFS_REPLAY_JOURNAL) {
                vnode_t devvp = NULL;
                int device_fd;
                if (namelen != 2) {
                        return (EINVAL);
                }
                device_fd = name[1];
                error = file_vnode(device_fd, &devvp);
                if (error) {
                        return error;
                }
                error = vnode_getwithref(devvp);
                if (error) {
                        file_drop(device_fd);
                        return error;
                }
                error = hfs_journal_replay(devvp, context);
                file_drop(device_fd);
                vnode_put(devvp);
                return error;
        }
#if DEBUG || !TARGET_OS_EMBEDDED
        else if (name[0] == HFS_ENABLE_RESIZE_DEBUG) {
                if (!kauth_cred_issuser(kauth_cred_get())) {
                        return (EPERM);
                }

                int old = hfs_resize_debug;

                int res = UREPLACE(oldp, oldlenp, newp, newlen, hfs_resize_debug);

                if (old != hfs_resize_debug) {
                        printf("hfs: %s resize debug\n",
                                   hfs_resize_debug ? "enabled" : "disabled");
                }

                return res;
        }
#endif

        return (ENOTSUP);
}

/* 
 * hfs_vfs_vget is not static since it is used in hfs_readwrite.c to support
 * the build_path ioctl.  We use it to leverage the code below that updates
 * the origin list cache if necessary
 */

int
hfs_vfs_vget(struct mount *mp, ino64_t ino, struct vnode **vpp, __unused vfs_context_t context)
{
        int error;
        int lockflags;
        struct hfsmount *hfsmp;

        hfsmp = VFSTOHFS(mp);

        error = hfs_vget(hfsmp, (cnid_t)ino, vpp, 1, 0);
        if (error)
                return error;

        /*
         * If the look-up was via the object ID (rather than the link ID),
         * then we make sure there's a parent here.  We can't leave this
         * until hfs_vnop_getattr because if there's a problem getting the
         * parent at that point, all the caller will do is call
         * hfs_vfs_vget again and we'll end up in an infinite loop.
         */

        cnode_t *cp = VTOC(*vpp);

        if (ISSET(cp->c_flag, C_HARDLINK) && ino == cp->c_fileid) {
                hfs_lock_always(cp, HFS_SHARED_LOCK);

                if (!hfs_haslinkorigin(cp)) {
                        if (!hfs_lock_upgrade(cp))
                                hfs_lock_always(cp, HFS_EXCLUSIVE_LOCK);

                        if (cp->c_cnid == cp->c_fileid) {
                                /*
                                 * Descriptor is stale, so we need to refresh it.  We
                                 * pick the first link.
                                 */
                                cnid_t link_id;

                                error = hfs_first_link(hfsmp, cp, &link_id);

                                if (!error) {
                                        lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG, HFS_SHARED_LOCK);
                                        error = cat_findname(hfsmp, link_id, &cp->c_desc);
                                        hfs_systemfile_unlock(hfsmp, lockflags);
                                }
                        } else {
                                // We'll use whatever link the descriptor happens to have
                                error = 0;
                        }
                        if (!error)
                                hfs_savelinkorigin(cp, cp->c_parentcnid);
                }

                hfs_unlock(cp);

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

        return error;
}


/*
 * 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.
 */
int
hfs_vget(struct hfsmount *hfsmp, cnid_t cnid, struct vnode **vpp, int skiplock, int allow_deleted)
{
        struct vnode *vp = NULLVP;
        struct cat_desc cndesc;
        struct cat_attr cnattr;
        struct cat_fork cnfork;
        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 our private directories. */
        if (cnid == hfsmp->hfs_private_desc[FILE_HARDLINKS].cd_cnid ||
            cnid == hfsmp->hfs_private_desc[DIR_HARDLINKS].cd_cnid) {
                return (ENOENT);
        }
        /*
         * Check the hash first
         */
        vp = hfs_chash_getvnode(hfsmp, cnid, 0, skiplock, allow_deleted);
        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 = (const u_int8_t *)&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_linkcount = 1;
                cnattr.ca_entries = 1;
                cnattr.ca_dircount = 1;
                cnattr.ca_mode = (S_IFDIR | S_IRWXU | S_IRWXG | S_IRWXO);
        } else {
                int lockflags;
                cnid_t pid;
                const char *nameptr;

                lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG, HFS_SHARED_LOCK);
                error = cat_idlookup(hfsmp, cnid, 0, 0, &cndesc, &cnattr, &cnfork);
                hfs_systemfile_unlock(hfsmp, lockflags);

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

                /*
                 * Check for a raw hardlink inode and save its linkref.
                 */
                pid = cndesc.cd_parentcnid;
                nameptr = (const char *)cndesc.cd_nameptr;

                if ((pid == hfsmp->hfs_private_desc[FILE_HARDLINKS].cd_cnid) &&
                        cndesc.cd_namelen > HFS_INODE_PREFIX_LEN &&
                    (bcmp(nameptr, HFS_INODE_PREFIX, HFS_INODE_PREFIX_LEN) == 0)) {
                        linkref = strtoul(&nameptr[HFS_INODE_PREFIX_LEN], NULL, 10);

                } else if ((pid == hfsmp->hfs_private_desc[DIR_HARDLINKS].cd_cnid) &&
                                   cndesc.cd_namelen > HFS_DIRINODE_PREFIX_LEN &&
                           (bcmp(nameptr, HFS_DIRINODE_PREFIX, HFS_DIRINODE_PREFIX_LEN) == 0)) {
                        linkref = strtoul(&nameptr[HFS_DIRINODE_PREFIX_LEN], NULL, 10);

                } else if ((pid == hfsmp->hfs_private_desc[FILE_HARDLINKS].cd_cnid) &&
                                   cndesc.cd_namelen > HFS_DELETE_PREFIX_LEN &&
                           (bcmp(nameptr, HFS_DELETE_PREFIX, HFS_DELETE_PREFIX_LEN) == 0)) {
                        *vpp = NULL;
                        cat_releasedesc(&cndesc);
                        return (ENOENT);  /* open unlinked file */
                }
        }

        /*
         * Finish initializing cnode descriptor for hardlinks.
         *
         * We need a valid name and parent for reverse lookups.
         */
        if (linkref) {
                cnid_t lastid;
                struct cat_desc linkdesc;
                int linkerr = 0;
                
                cnattr.ca_linkref = linkref;
                bzero (&linkdesc, sizeof (linkdesc));

                /* 
                 * If the caller supplied the raw inode value, then we don't know exactly
                 * which hardlink they wanted. It's likely that they acquired the raw inode
                 * value BEFORE the item became a hardlink, in which case, they probably
                 * want the oldest link.  So request the oldest link from the catalog.
                 * 
                 * Unfortunately, this requires that we iterate through all N hardlinks. On the plus
                 * side, since we know that we want the last linkID, we can also have this one
                 * call give us back the name of the last ID, since it's going to have it in-hand...
                 */
                linkerr = hfs_lookup_lastlink (hfsmp, linkref, &lastid, &linkdesc);
                if ((linkerr == 0) && (lastid != 0)) {
                        /* 
                         * Release any lingering buffers attached to our local descriptor.
                         * Then copy the name and other business into the cndesc 
                         */
                        cat_releasedesc (&cndesc);
                        bcopy (&linkdesc, &cndesc, sizeof(linkdesc));   
                }       
                /* If it failed, the linkref code will just use whatever it had in-hand below. */
        }

        if (linkref) {
                int newvnode_flags = 0;
                
                error = hfs_getnewvnode(hfsmp, NULL, NULL, &cndesc, 0, &cnattr,
                                                                &cnfork, &vp, &newvnode_flags);
                if (error == 0) {
                        VTOC(vp)->c_flag |= C_HARDLINK;
                        vnode_setmultipath(vp);
                }
        } else {
                int newvnode_flags = 0;

                void *buf = hfs_malloc(MAXPATHLEN);

                /* Supply hfs_getnewvnode with a component name. */
                struct componentname cn = {
                        .cn_nameiop = LOOKUP,
                        .cn_flags       = ISLASTCN,
                        .cn_pnlen       = MAXPATHLEN,
                        .cn_namelen = cndesc.cd_namelen,
                        .cn_pnbuf       = buf,
                        .cn_nameptr = buf
                };

                bcopy(cndesc.cd_nameptr, cn.cn_nameptr, cndesc.cd_namelen + 1);

                error = hfs_getnewvnode(hfsmp, NULLVP, &cn, &cndesc, 0, &cnattr, 
                                                                &cnfork, &vp, &newvnode_flags);

                if (error == 0 && (VTOC(vp)->c_flag & C_HARDLINK)) {
                        hfs_savelinkorigin(VTOC(vp), cndesc.cd_parentcnid);
                }

                hfs_free(buf, MAXPATHLEN);
        }
        cat_releasedesc(&cndesc);

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


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

        hfsmp = VFSTOHFS(mp);

        accounted_root_usecounts = 0;
#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.
         */
        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)
                                ++accounted_root_usecounts;
                }
        }
#endif /* QUOTA */

        if (accounted_root_usecounts > 0) {
                /* Obtain the root vnode so we can skip over it. */
                skipvp = hfs_chash_getvnode(hfsmp, kHFSRootFolderID, 0, 0, 0);
        }

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

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

        if (skipvp) {
                /*
                 * See if there are additional references on the
                 * root vp besides the ones obtained from the open
                 * quota files and CoreStorage.
                 */
                if ((error == 0) &&
                    (vnode_isinuse(skipvp,  accounted_root_usecounts))) {
                        error = EBUSY;  /* root directory is still open */
                }
                hfs_unlock(VTOC(skipvp));
                /* release the iocount from the hfs_chash_getvnode call above. */
                vnode_put(skipvp);
        }
        if (error && (flags & FORCECLOSE) == 0)
                return (error);

#if QUOTA
        if (((unsigned int)vfs_flags(mp)) & MNT_QUOTA) {
                for (i = 0; i < MAXQUOTAS; i++) {
                        if (hfsmp->hfs_qfiles[i].qf_vp == NULLVP)
                                continue;
                        hfs_quotaoff(p, mp, i);
                }
        }
#endif /* QUOTA */

        if (skipvp) {
                error = vflush(mp, NULLVP, SKIPSYSTEM | flags);
        }

        return (error);
}

/*
 * Update volume encoding bitmap (HFS Plus only)
 * 
 * Mark a legacy text encoding as in-use (as needed)
 * in the volume header of this HFS+ filesystem.
 */
void
hfs_setencodingbits(struct hfsmount *hfsmp, u_int32_t encoding)
{
#define  kIndexMacUkrainian     48  /* MacUkrainian encoding is 152 */
#define  kIndexMacFarsi         49  /* MacFarsi encoding is 140 */

        u_int32_t       index;

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

        /* Only mark the encoding as in-use if it wasn't already set */
        if (index < 64 && (hfsmp->encodingsBitmap & (u_int64_t)(1ULL << index)) == 0) {
                hfs_lock_mount (hfsmp);
                hfsmp->encodingsBitmap |= (u_int64_t)(1ULL << index);
                MarkVCBDirty(hfsmp);
                hfs_unlock_mount(hfsmp);
        }
}

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

        microtime(&tv);

        hfs_lock_mount (hfsmp);

        MarkVCBDirty(hfsmp);
        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;
        }

        hfs_unlock_mount (hfsmp);

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

        return (0);
}


#if CONFIG_HFS_STD
/* HFS Standard MDB flush */
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 sector_size;
        ByteCount namelen;

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

        hfs_lock_mount (hfsmp);

        mdb = (HFSMasterDirectoryBlock *)(buf_dataptr(bp) + HFS_PRI_OFFSET(sector_size));
    
        mdb->drCrDate   = SWAP_BE32 (UTCToLocal(to_hfs_time(vcb->hfs_itime)));
        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((char *)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 );

        hfs_unlock_mount (hfsmp);

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

                if (buf_meta_bread(hfsmp->hfs_devvp, hfsmp->hfs_partition_avh_sector, sector_size, NOCRED, &alt_bp) == 0) {
                        bcopy(mdb, (char *)buf_dataptr(alt_bp) + HFS_ALT_OFFSET(sector_size), 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);
}
#endif

/*
 *  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+".
 */
int
hfs_flushvolumeheader(struct hfsmount *hfsmp, 
                                          hfs_flush_volume_header_options_t options)
{
        ExtendedVCB *vcb = HFSTOVCB(hfsmp);
        struct filefork *fp;
        HFSPlusVolumeHeader *volumeHeader, *altVH;
        int retval;
        struct buf *bp, *alt_bp;
        int i;
        daddr64_t priIDSector;
        bool critical = false;
        u_int16_t  signature;
        u_int16_t  hfsversion;
        daddr64_t avh_sector;
        bool altflush = ISSET(options, HFS_FVH_WRITE_ALT);

        if (ISSET(options, HFS_FVH_FLUSH_IF_DIRTY)
                && !hfs_header_needs_flushing(hfsmp)) {
                return 0;
        }

        if (hfsmp->hfs_flags & HFS_READ_ONLY) {
                return(0);
        }
#if CONFIG_HFS_STD
        if (hfsmp->hfs_flags & HFS_STANDARD) {
                return hfs_flushMDB(hfsmp, ISSET(options, HFS_FVH_WAIT) ? MNT_WAIT : 0, altflush);
        }
#endif
        priIDSector = (daddr64_t)((vcb->hfsPlusIOPosOffset / hfsmp->hfs_logical_block_size) +
                                  HFS_PRI_SECTOR(hfsmp->hfs_logical_block_size));

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

        bp = NULL;
        alt_bp = NULL;

        retval = (int)buf_meta_bread(hfsmp->hfs_devvp, 
                        HFS_PHYSBLK_ROUNDDOWN(priIDSector, hfsmp->hfs_log_per_phys),
                        hfsmp->hfs_physical_block_size, NOCRED, &bp);
        if (retval) {
                printf("hfs: err %d reading VH blk (vol=%s)\n", retval, vcb->vcbVN);
                goto err_exit;
        }

        volumeHeader = (HFSPlusVolumeHeader *)((char *)buf_dataptr(bp) + 
                        HFS_PRI_OFFSET(hfsmp->hfs_physical_block_size));

        /*
         * Sanity check what we just read.  If it's bad, try the alternate
         * instead.
         */
        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)) {
                printf("hfs: corrupt VH on %s, sig 0x%04x, ver %d, blksize %d\n",
                                vcb->vcbVN, signature, hfsversion, 
                                SWAP_BE32 (volumeHeader->blockSize));
                hfs_mark_inconsistent(hfsmp, HFS_INCONSISTENCY_DETECTED);

                /* Almost always we read AVH relative to the partition size */
                avh_sector = hfsmp->hfs_partition_avh_sector;

                if (hfsmp->hfs_partition_avh_sector != hfsmp->hfs_fs_avh_sector) {
                        /* 
                         * The two altVH offsets do not match --- which means that a smaller file 
                         * system exists in a larger partition.  Verify that we have the correct 
                         * alternate volume header sector as per the current parititon size.  
                         * The GPT device that we are mounted on top could have changed sizes 
                         * without us knowing. 
                         *
                         * We're in a transaction, so it's safe to modify the partition_avh_sector 
                         * field if necessary.
                         */

                        uint64_t sector_count;

                        /* Get underlying device block count */
                        if ((retval = VNOP_IOCTL(hfsmp->hfs_devvp, DKIOCGETBLOCKCOUNT, 
                                                        (caddr_t)&sector_count, 0, vfs_context_current()))) {
                                printf("hfs_flushVH: err %d getting block count (%s) \n", retval, vcb->vcbVN);
                                retval = ENXIO;
                                goto err_exit;
                        }
                        
                        /* Partition size was changed without our knowledge */
                        if (sector_count != (uint64_t)hfsmp->hfs_logical_block_count) {
                                hfsmp->hfs_partition_avh_sector = (hfsmp->hfsPlusIOPosOffset / hfsmp->hfs_logical_block_size) + 
                                        HFS_ALT_SECTOR(hfsmp->hfs_logical_block_size, sector_count);
                                /* Note: hfs_fs_avh_sector will remain unchanged */
                                printf ("hfs_flushVH: partition size changed, partition_avh_sector=%qu, fs_avh_sector=%qu\n",
                                                hfsmp->hfs_partition_avh_sector, hfsmp->hfs_fs_avh_sector);

                                /* 
                                 * We just updated the offset for AVH relative to 
                                 * the partition size, so the content of that AVH
                                 * will be invalid.  But since we are also maintaining 
                                 * a valid AVH relative to the file system size, we 
                                 * can read it since primary VH and partition AVH 
                                 * are not valid. 
                                 */
                                avh_sector = hfsmp->hfs_fs_avh_sector;
                        }
                }

                printf ("hfs: trying alternate (for %s) avh_sector=%qu\n", 
                                (avh_sector == hfsmp->hfs_fs_avh_sector) ? "file system" : "partition", avh_sector);

                if (avh_sector) {
                        retval = buf_meta_bread(hfsmp->hfs_devvp, 
                            HFS_PHYSBLK_ROUNDDOWN(avh_sector, hfsmp->hfs_log_per_phys),
                            hfsmp->hfs_physical_block_size, NOCRED, &alt_bp);
                        if (retval) {
                                printf("hfs: err %d reading alternate VH (%s)\n", retval, vcb->vcbVN);
                                goto err_exit;
                        }
                        
                        altVH = (HFSPlusVolumeHeader *)((char *)buf_dataptr(alt_bp) + 
                                HFS_ALT_OFFSET(hfsmp->hfs_physical_block_size));
                        signature = SWAP_BE16(altVH->signature);
                        hfsversion = SWAP_BE16(altVH->version);
                        
                        if ((signature != kHFSPlusSigWord && signature != kHFSXSigWord) ||
                            (hfsversion < kHFSPlusVersion) || (kHFSPlusVersion > 100) ||
                            (SWAP_BE32(altVH->blockSize) != vcb->blockSize)) {
                                printf("hfs: corrupt alternate VH on %s, sig 0x%04x, ver %d, blksize %d\n",
                                    vcb->vcbVN, signature, hfsversion,
                                    SWAP_BE32(altVH->blockSize));
                                retval = EIO;
                                goto err_exit;
                        }
                        
                        /* The alternate is plausible, so use it. */
                        bcopy(altVH, volumeHeader, kMDBSize);
                        buf_brelse(alt_bp);
                        alt_bp = NULL;
                } else {
                        /* No alternate VH, nothing more we can do. */
                        retval = EIO;
                        goto err_exit;
                }
        }

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

        /*
         * 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, 
                                HFS_PHYSBLK_ROUNDDOWN(HFS_PRI_SECTOR(hfsmp->hfs_logical_block_size), hfsmp->hfs_log_per_phys),
                                hfsmp->hfs_physical_block_size, NOCRED, &bp2);
                if (retval) {
                        if (bp2)
                                buf_brelse(bp2);
                        retval = 0;
                } else {
                        mdb = (HFSMasterDirectoryBlock *)(buf_dataptr(bp2) +
                                HFS_PRI_OFFSET(hfsmp->hfs_physical_block_size));

                        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, NULL, NULL);
                                } else {
                                        (void) VNOP_BWRITE(bp2);                /* write out the changes */
                                }
                          }
                        else
                          {
                                buf_brelse(bp2);                                                /* just release it */
                          }
                  }     
        }

        hfs_lock_mount (hfsmp);

        /* 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 + vcb->reclaimBlocks);
        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 = true;
        }

        if (!altflush && !ISSET(options, HFS_FVH_FLUSH_IF_DIRTY)) {
                goto done;
        }

        /* 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;
                altflush = true;
        }

        /* 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;
                altflush = true;
        }

        /* 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;
                altflush = true;
        }

        /* 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);
                }
                if (ISSET(FTOC(fp)->c_flag, C_MODIFIED)) {
                        FTOC(fp)->c_flag &= ~C_MODIFIED;
                        altflush = true;
                }
                volumeHeader->attributesFile.logicalSize = SWAP_BE64 (fp->ff_size);
                volumeHeader->attributesFile.totalBlocks = SWAP_BE32 (fp->ff_blocks);
                volumeHeader->attributesFile.clumpSize   = SWAP_BE32 (fp->ff_clumpsize);
        }

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

        if (altflush)
                critical = true;
 
done:
        MarkVCBClean(hfsmp);
        hfs_unlock_mount (hfsmp);

        /* If requested, flush out the alternate volume header */
        if (altflush) {
                /* 
                 * The two altVH offsets do not match --- which means that a smaller file 
                 * system exists in a larger partition.  Verify that we have the correct 
                 * alternate volume header sector as per the current parititon size.  
                 * The GPT device that we are mounted on top could have changed sizes 
                 * without us knowning. 
                 *
                 * We're in a transaction, so it's safe to modify the partition_avh_sector 
                 * field if necessary.
                 */
                if (hfsmp->hfs_partition_avh_sector != hfsmp->hfs_fs_avh_sector) {
                        uint64_t sector_count;

                        /* Get underlying device block count */
                        if ((retval = VNOP_IOCTL(hfsmp->hfs_devvp, DKIOCGETBLOCKCOUNT, 
                                                        (caddr_t)&sector_count, 0, vfs_context_current()))) {
                                printf("hfs_flushVH: err %d getting block count (%s) \n", retval, vcb->vcbVN);
                                retval = ENXIO;
                                goto err_exit;
                        }
                        
                        /* Partition size was changed without our knowledge */
                        if (sector_count != (uint64_t)hfsmp->hfs_logical_block_count) {
                                hfsmp->hfs_partition_avh_sector = (hfsmp->hfsPlusIOPosOffset / hfsmp->hfs_logical_block_size) + 
                                        HFS_ALT_SECTOR(hfsmp->hfs_logical_block_size, sector_count);
                                /* Note: hfs_fs_avh_sector will remain unchanged */
                                printf ("hfs_flushVH: altflush: partition size changed, partition_avh_sector=%qu, fs_avh_sector=%qu\n",
                                                hfsmp->hfs_partition_avh_sector, hfsmp->hfs_fs_avh_sector);
                        }
                }

                /*
                 * First see if we need to write I/O to the "secondary" AVH 
                 * located at FS Size - 1024 bytes, because this one will 
                 * always go into the journal.  We put this AVH into the journal
                 * because even if the filesystem size has shrunk, this LBA should be 
                 * reachable after the partition-size modification has occurred.  
                 * The one where we need to be careful is partitionsize-1024, since the
                 * partition size should hopefully shrink. 
                 *
                 * Most of the time this block will not execute.
                 */
                if ((hfsmp->hfs_fs_avh_sector) && 
                                (hfsmp->hfs_partition_avh_sector != hfsmp->hfs_fs_avh_sector)) {
                        if (buf_meta_bread(hfsmp->hfs_devvp, 
                                                HFS_PHYSBLK_ROUNDDOWN(hfsmp->hfs_fs_avh_sector, hfsmp->hfs_log_per_phys),
                                                hfsmp->hfs_physical_block_size, 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(hfsmp->hfs_physical_block_size), 
                                                kMDBSize);

                                if (hfsmp->jnl) {
                                        journal_modify_block_end(hfsmp->jnl, alt_bp, NULL, NULL);
                                } else {
                                        (void) VNOP_BWRITE(alt_bp);
                                }
                        } else if (alt_bp) {
                                buf_brelse(alt_bp);
                        }
                }
                
                /* 
                 * Flush out alternate volume header located at 1024 bytes before
                 * end of the partition as part of journal transaction.  In 
                 * most cases, this will be the only alternate volume header 
                 * that we need to worry about because the file system size is 
                 * same as the partition size, therefore hfs_fs_avh_sector is 
                 * same as hfs_partition_avh_sector. This is the "priority" AVH. 
                 *
                 * However, do not always put this I/O into the journal.  If we skipped the
                 * FS-Size AVH write above, then we will put this I/O into the journal as 
                 * that indicates the two were in sync.  However, if the FS size is
                 * not the same as the partition size, we are tracking two.  We don't
                 * put it in the journal in that case, since if the partition
                 * size changes between uptimes, and we need to replay the journal,
                 * this I/O could generate an EIO if during replay it is now trying 
                 * to access blocks beyond the device EOF.  
                 */
                if (hfsmp->hfs_partition_avh_sector) {
                        if (buf_meta_bread(hfsmp->hfs_devvp, 
                                                HFS_PHYSBLK_ROUNDDOWN(hfsmp->hfs_partition_avh_sector, hfsmp->hfs_log_per_phys),
                                                hfsmp->hfs_physical_block_size, NOCRED, &alt_bp) == 0) {

                                /* only one AVH, put this I/O in the journal. */
                                if ((hfsmp->jnl) && (hfsmp->hfs_partition_avh_sector == hfsmp->hfs_fs_avh_sector)) {
                                        journal_modify_block_start(hfsmp->jnl, alt_bp);
                                }

                                bcopy(volumeHeader, (char *)buf_dataptr(alt_bp) + 
                                                HFS_ALT_OFFSET(hfsmp->hfs_physical_block_size), 
                                                kMDBSize);

                                /* If journaled and we only have one AVH to track */
                                if ((hfsmp->jnl) && (hfsmp->hfs_partition_avh_sector == hfsmp->hfs_fs_avh_sector)) {
                                        journal_modify_block_end (hfsmp->jnl, alt_bp, NULL, NULL);
                                } else {
                                        /* 
                                         * If we don't have a journal or there are two AVH's at the
                                         * moment, then this one doesn't go in the journal.  Note that 
                                         * this one may generate I/O errors, since the partition
                                         * can be resized behind our backs at any moment and this I/O 
                                         * may now appear to be beyond the device EOF.
                                         */
                                        (void) VNOP_BWRITE(alt_bp);
                                        hfs_flush(hfsmp, HFS_FLUSH_CACHE);
                                }               
                        } else if (alt_bp) {
                                buf_brelse(alt_bp);
                        }
                }
        }

        /* Finish modifying the block for the primary VH */
        if (hfsmp->jnl) {
                journal_modify_block_end(hfsmp->jnl, bp, NULL, NULL);
        } else {
                if (!ISSET(options, HFS_FVH_WAIT)) {
                        buf_bawrite(bp);
                } else {
                        retval = VNOP_BWRITE(bp);
                        /* When critical data changes, flush the device cache */
                        if (critical && (retval == 0)) {
                                hfs_flush(hfsmp, HFS_FLUSH_CACHE);
                        }
                }
        }
        hfs_end_transaction(hfsmp);
 
        return (retval);

err_exit:
        if (alt_bp)
                buf_brelse(alt_bp);
        if (bp)
                buf_brelse(bp);
        hfs_end_transaction(hfsmp);
        return retval;
}


/*
 * Creates a UUID from a unique "name" in the HFS UUID Name space.
 * See version 3 UUID.
 */
static void
hfs_getvoluuid(struct hfsmount *hfsmp, uuid_t result)
{
        MD5_CTX  md5c;
        uint8_t  rawUUID[8];

        ((uint32_t *)rawUUID)[0] = hfsmp->vcbFndrInfo[6];
        ((uint32_t *)rawUUID)[1] = hfsmp->vcbFndrInfo[7];

        MD5Init( &md5c );
        MD5Update( &md5c, HFS_UUID_NAMESPACE_ID, sizeof( uuid_t ) );
        MD5Update( &md5c, rawUUID, sizeof (rawUUID) );
        MD5Final( result, &md5c );

        result[6] = 0x30 | ( result[6] & 0x0F );
        result[8] = 0x80 | ( result[8] & 0x3F );
}

/*
 * Get file system attributes.
 */
static int
hfs_vfs_getattr(struct mount *mp, struct vfs_attr *fsap, __unused vfs_context_t context)
{
#define HFS_ATTR_FILE_VALIDMASK (ATTR_FILE_VALIDMASK & ~(ATTR_FILE_FILETYPE | ATTR_FILE_FORKCOUNT | ATTR_FILE_FORKLIST))
#define HFS_ATTR_CMN_VOL_VALIDMASK (ATTR_CMN_VALIDMASK & ~(ATTR_CMN_ACCTIME))

        ExtendedVCB *vcb = VFSTOVCB(mp);
        struct hfsmount *hfsmp = VFSTOHFS(mp);

        int searchfs_on = 0;
        int exchangedata_on = 1;

#if CONFIG_SEARCHFS
        searchfs_on = 1;
#endif

#if CONFIG_PROTECT
        if (cp_fs_protected(mp)) {
                exchangedata_on = 0;
        }
#endif

        VFSATTR_RETURN(fsap, f_objcount, (u_int64_t)hfsmp->vcbFilCnt + (u_int64_t)hfsmp->vcbDirCnt);
        VFSATTR_RETURN(fsap, f_filecount, (u_int64_t)hfsmp->vcbFilCnt);
        VFSATTR_RETURN(fsap, f_dircount, (u_int64_t)hfsmp->vcbDirCnt);
        VFSATTR_RETURN(fsap, f_maxobjcount, (u_int64_t)0xFFFFFFFF);
        VFSATTR_RETURN(fsap, f_iosize, (size_t)cluster_max_io_size(mp, 0));
        VFSATTR_RETURN(fsap, f_blocks, (u_int64_t)hfsmp->totalBlocks);
        VFSATTR_RETURN(fsap, f_bfree, (u_int64_t)hfs_freeblks(hfsmp, 0));
        VFSATTR_RETURN(fsap, f_bavail, (u_int64_t)hfs_freeblks(hfsmp, 1));
        VFSATTR_RETURN(fsap, f_bsize, (u_int32_t)vcb->blockSize);
        /* XXX needs clarification */
        VFSATTR_RETURN(fsap, f_bused, hfsmp->totalBlocks - hfs_freeblks(hfsmp, 1));
        VFSATTR_RETURN(fsap, f_files, (u_int64_t)HFS_MAX_FILES);
        VFSATTR_RETURN(fsap, f_ffree, (u_int64_t)hfs_free_cnids(hfsmp));

        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) == 0) {
                        /* HFS+ & variants */
                        cap->capabilities[VOL_CAPABILITIES_FORMAT] =
                                VOL_CAP_FMT_PERSISTENTOBJECTIDS |
                                VOL_CAP_FMT_SYMBOLICLINKS |
                                VOL_CAP_FMT_HARDLINKS |
                                VOL_CAP_FMT_JOURNAL |
                                VOL_CAP_FMT_ZERO_RUNS |
                                (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 |
                                VOL_CAP_FMT_HIDDEN_FILES |
#if HFS_COMPRESSION
                                VOL_CAP_FMT_DECMPFS_COMPRESSION |
#endif
#if CONFIG_HFS_DIRLINK
                                VOL_CAP_FMT_DIR_HARDLINKS |
#endif
                                VOL_CAP_FMT_PATH_FROM_ID;
                }
#if CONFIG_HFS_STD
                else {
                        /* HFS standard */
                        cap->capabilities[VOL_CAPABILITIES_FORMAT] =
                                VOL_CAP_FMT_PERSISTENTOBJECTIDS |
                                VOL_CAP_FMT_CASE_PRESERVING |
                                VOL_CAP_FMT_FAST_STATFS |
                                VOL_CAP_FMT_HIDDEN_FILES |
                                VOL_CAP_FMT_PATH_FROM_ID;
                }
#endif

                /*
                 * The capabilities word in 'cap' tell you whether or not 
                 * this particular filesystem instance has feature X enabled.
                 */

                cap->capabilities[VOL_CAPABILITIES_INTERFACES] =
                        VOL_CAP_INT_ATTRLIST |
                        VOL_CAP_INT_NFSEXPORT |
                        VOL_CAP_INT_READDIRATTR |
                        VOL_CAP_INT_ALLOCATE |
                        VOL_CAP_INT_VOL_RENAME |
                        VOL_CAP_INT_ADVLOCK |
                        VOL_CAP_INT_FLOCK |
#if VOL_CAP_INT_RENAME_EXCL
                        VOL_CAP_INT_RENAME_EXCL |
#endif
#if NAMEDSTREAMS
                        VOL_CAP_INT_EXTENDED_ATTR |
                        VOL_CAP_INT_NAMEDSTREAMS;
#else
                        VOL_CAP_INT_EXTENDED_ATTR;
#endif
                
                /* HFS may conditionally support searchfs and exchangedata depending on the runtime */

                if (searchfs_on) {
                        cap->capabilities[VOL_CAPABILITIES_INTERFACES] |= VOL_CAP_INT_SEARCHFS;
                }
                if (exchangedata_on) {
                        cap->capabilities[VOL_CAPABILITIES_INTERFACES] |= VOL_CAP_INT_EXCHANGEDATA;
                }

                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 |
                        VOL_CAP_FMT_OPENDENYMODES |
                        VOL_CAP_FMT_HIDDEN_FILES |
                        VOL_CAP_FMT_PATH_FROM_ID |
                        VOL_CAP_FMT_DECMPFS_COMPRESSION |
                        VOL_CAP_FMT_DIR_HARDLINKS;

                /*
                 * Bits in the "valid" field tell you whether or not the on-disk
                 * format supports feature X.
                 */

                cap->valid[VOL_CAPABILITIES_INTERFACES] =
                        VOL_CAP_INT_ATTRLIST |
                        VOL_CAP_INT_NFSEXPORT |
                        VOL_CAP_INT_READDIRATTR |
                        VOL_CAP_INT_COPYFILE |
                        VOL_CAP_INT_ALLOCATE |
                        VOL_CAP_INT_VOL_RENAME |
                        VOL_CAP_INT_ADVLOCK |
                        VOL_CAP_INT_FLOCK |
                        VOL_CAP_INT_MANLOCK |
#if VOL_CAP_INT_RENAME_EXCL
                        VOL_CAP_INT_RENAME_EXCL |
#endif

#if NAMEDSTREAMS
                        VOL_CAP_INT_EXTENDED_ATTR |
                        VOL_CAP_INT_NAMEDSTREAMS;
#else
                        VOL_CAP_INT_EXTENDED_ATTR;
#endif

                /* HFS always supports exchangedata and searchfs in the on-disk format natively */
                cap->valid[VOL_CAPABILITIES_INTERFACES] |= (VOL_CAP_INT_SEARCHFS | VOL_CAP_INT_EXCHANGEDATA);


                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 = HFS_ATTR_CMN_VOL_VALIDMASK;
                attrp->validattr.volattr = ATTR_VOL_VALIDMASK & ~ATTR_VOL_INFO;
                attrp->validattr.dirattr = ATTR_DIR_VALIDMASK;
                attrp->validattr.fileattr = HFS_ATTR_FILE_VALIDMASK;
                attrp->validattr.forkattr = 0;

                attrp->nativeattr.commonattr = HFS_ATTR_CMN_VOL_VALIDMASK;
                attrp->nativeattr.volattr = ATTR_VOL_VALIDMASK & ~ATTR_VOL_INFO;
                attrp->nativeattr.dirattr = ATTR_DIR_VALIDMASK;
                attrp->nativeattr.fileattr = HFS_ATTR_FILE_VALIDMASK;
                attrp->nativeattr.forkattr = 0;
                VFSATTR_SET_SUPPORTED(fsap, f_attributes);
        }
        fsap->f_create_time.tv_sec = hfsmp->hfs_itime;
        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)) {
                u_int16_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) == 0) {
                        if (hfsmp->jnl) {
                                subtype |= HFS_SUBTYPE_JOURNALED;
                        }
                        if (hfsmp->hfs_flags & HFS_CASE_SENSITIVE) {
                                subtype |= HFS_SUBTYPE_CASESENSITIVE;
                        }
                }
#if CONFIG_HFS_STD
                else {
                        subtype = HFS_SUBTYPE_STANDARDHFS;
                } 
#endif
                fsap->f_fssubtype = subtype;
                VFSATTR_SET_SUPPORTED(fsap, f_fssubtype);
        }

        if (VFSATTR_IS_ACTIVE(fsap, f_vol_name)) {
                strlcpy(fsap->f_vol_name, (char *) hfsmp->vcbVN, MAXPATHLEN);
                VFSATTR_SET_SUPPORTED(fsap, f_vol_name);
        }
        if (VFSATTR_IS_ACTIVE(fsap, f_uuid)) {
                hfs_getvoluuid(hfsmp, fsap->f_uuid);
                VFSATTR_SET_SUPPORTED(fsap, f_uuid);
        }
        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;
        char converted_volname[256];
        size_t volname_length = 0;
        size_t conv_volname_length = 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 = (const u_int8_t *)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, HFS_LOCK_DEFAULT)) == 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 == 0) {
                                        strlcpy((char *)vcb->vcbVN, name, sizeof(vcb->vcbVN));

                                        volname_length = strlen ((const char*)vcb->vcbVN);
                                        /* Send the volume name down to CoreStorage if necessary */     
                                        error = utf8_normalizestr(vcb->vcbVN, volname_length, (u_int8_t*)converted_volname, &conv_volname_length, 256, UTF_PRECOMPOSED);
                                        if (error == 0) {
                                                (void) VNOP_IOCTL (hfsmp->hfs_devvp, _DKIOCCSSETLVNAME, converted_volname, 0, vfs_context_current());
                                        }
                                        error = 0;
                                }
                                
                                hfs_systemfile_unlock(hfsmp, lockflags);
                                cat_postflight(hfsmp, &cookie, p);
                        
                                if (error)
                                        MarkVCBDirty(vcb);
                                (void) hfs_flushvolumeheader(hfsmp, HFS_FVH_WAIT);
                        }
                        hfs_end_transaction(hfsmp);
                }                       
                if (!error) {
                        /* Release old allocated name buffer */
                        if (cp->c_desc.cd_flags & CD_HASBUF) {
                                const char *tmp_name = (const char *)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(tmp_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, 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;
}

/* If a runtime corruption is detected, set the volume inconsistent 
 * bit in the volume attributes.  The volume inconsistent bit is a persistent
 * bit which represents that the volume is corrupt and needs repair.  
 * The volume inconsistent bit can be set from the kernel when it detects
 * runtime corruption or from file system repair utilities like fsck_hfs when
 * a repair operation fails.  The bit should be cleared only from file system 
 * verify/repair utility like fsck_hfs when a verify/repair succeeds.
 */
void hfs_mark_inconsistent(struct hfsmount *hfsmp,
                                                                  hfs_inconsistency_reason_t reason)
{
        hfs_lock_mount (hfsmp);
        if ((hfsmp->vcbAtrb & kHFSVolumeInconsistentMask) == 0) {
                hfsmp->vcbAtrb |= kHFSVolumeInconsistentMask;
                MarkVCBDirty(hfsmp);
        }
        if ((hfsmp->hfs_flags & HFS_READ_ONLY)==0) {
                switch (reason) {
                case HFS_INCONSISTENCY_DETECTED:
                        printf("hfs_mark_inconsistent: Runtime corruption detected on %s, fsck will be forced on next mount.\n", 
                                   hfsmp->vcbVN);
                        break;
                case HFS_ROLLBACK_FAILED:
                        printf("hfs_mark_inconsistent: Failed to roll back; volume `%s' might be inconsistent; fsck will be forced on next mount.\n", 
                                   hfsmp->vcbVN);
                        break;
                case HFS_OP_INCOMPLETE:
                        printf("hfs_mark_inconsistent: Failed to complete operation; volume `%s' might be inconsistent; fsck will be forced on next mount.\n", 
                                   hfsmp->vcbVN);
                        break;
                case HFS_FSCK_FORCED:
                        printf("hfs_mark_inconsistent: fsck requested for `%s'; fsck will be forced on next mount.\n",
                                   hfsmp->vcbVN);
                        break;  
                }
        }
        hfs_unlock_mount (hfsmp);
}

/* Replay the journal on the device node provided.  Returns zero if
 * journal replay succeeded or no journal was supposed to be replayed.
 */
static int hfs_journal_replay(vnode_t devvp, vfs_context_t context)
{
        int retval = 0;
        int error = 0;

        /* Replay allowed only on raw devices */
        if (!vnode_ischr(devvp) && !vnode_isblk(devvp))
                return EINVAL;

        retval = hfs_mountfs(devvp, NULL, NULL, /* journal_replay_only: */ 1, context);
        buf_flushdirtyblks(devvp, TRUE, 0, "hfs_journal_replay");
        
        /* FSYNC the devnode to be sure all data has been flushed */
        error = VNOP_FSYNC(devvp, MNT_WAIT, context);
        if (error) {
                retval = error;
        }

        return retval;
}


/* 
 * Cancel the syncer
 */
static void
hfs_syncer_free(struct hfsmount *hfsmp)
{
    if (hfsmp && ISSET(hfsmp->hfs_flags, HFS_RUN_SYNCER)) {
        hfs_syncer_lock(hfsmp);
                CLR(hfsmp->hfs_flags, HFS_RUN_SYNCER);
        hfs_syncer_unlock(hfsmp);

        // Wait for the syncer thread to finish
        if (hfsmp->hfs_syncer_thread) {
                        hfs_syncer_wakeup(hfsmp);
                        hfs_syncer_lock(hfsmp);
                        while (hfsmp->hfs_syncer_thread)
                                hfs_syncer_wait(hfsmp, NULL);
                        hfs_syncer_unlock(hfsmp);
        }
    }
}

static int hfs_vfs_ioctl(struct mount *mp, u_long command, caddr_t data,
                                                 __unused int flags, __unused vfs_context_t context)
{
        switch (command) {
#if CONFIG_PROTECT
        case FIODEVICELOCKED:
                cp_device_locked_callback(mp, (cp_lock_state_t)data);
                return 0;
#endif
        }
        return ENOTTY;
}

/*
 * hfs vfs operations.
 */
struct vfsops hfs_vfsops = {
        .vfs_mount     = hfs_mount,
        .vfs_start     = hfs_start,
        .vfs_unmount   = hfs_unmount,
        .vfs_root      = hfs_vfs_root,
        .vfs_quotactl  = hfs_quotactl,
        .vfs_getattr   = hfs_vfs_getattr,
        .vfs_sync      = hfs_sync,
        .vfs_vget      = hfs_vfs_vget,
        .vfs_fhtovp    = hfs_fhtovp,
        .vfs_vptofh    = hfs_vptofh,
        .vfs_init      = hfs_init,
        .vfs_sysctl    = hfs_sysctl,
        .vfs_setattr   = hfs_vfs_setattr,
        .vfs_ioctl         = hfs_vfs_ioctl,
};