hfs-366.1.1.tar.gz

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

/*
 * Copyright (c) 2000-2015 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.
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/*      @(#)hfs_vfsutils.c      4.0
*
*       (c) 1997-2002 Apple Inc.  All Rights Reserved
*
*       hfs_vfsutils.c -- Routines that go between the HFS layer and the VFS.
*
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <sys/vm.h>
#include <sys/buf.h>
#include <sys/ubc.h>
#include <sys/unistd.h>
#include <sys/utfconv.h>
#include <sys/kauth.h>
#include <sys/fcntl.h>
#include <sys/fsctl.h>
#include <sys/mount.h>
#include <sys/sysctl.h>
#include <kern/clock.h>
#include <stdbool.h>
#include <miscfs/specfs/specdev.h>
#include <libkern/OSAtomic.h>
#include <IOKit/IOLib.h>

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

#include "hfs_iokit.h"
#include "hfs.h"
#include "hfs_catalog.h"
#include "hfs_dbg.h"
#include "hfs_mount.h"
#include "hfs_endian.h"
#include "hfs_cnode.h"
#include "hfs_fsctl.h"
#include "hfs_cprotect.h"

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

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

static void ReleaseMetaFileVNode(struct vnode *vp);
static int  hfs_late_journal_init(struct hfsmount *hfsmp, HFSPlusVolumeHeader *vhp, void *_args);

static u_int32_t hfs_hotfile_freeblocks(struct hfsmount *);
static void hfs_thaw_locked(struct hfsmount *hfsmp);

#define HFS_MOUNT_DEBUG 1


//*******************************************************************************
// Note: Finder information in the HFS/HFS+ metadata are considered opaque and
//       hence are not in the right byte order on little endian machines. It is
//       the responsibility of the finder and other clients to swap the data.
//*******************************************************************************

//*******************************************************************************
//      Routine:        hfs_MountHFSVolume
//
//
//*******************************************************************************
unsigned char hfs_catname[] = "Catalog B-tree";
unsigned char hfs_extname[] = "Extents B-tree";
unsigned char hfs_vbmname[] = "Volume Bitmap";
unsigned char hfs_attrname[] = "Attribute B-tree";
unsigned char hfs_startupname[] = "Startup File";

#if CONFIG_HFS_STD
OSErr hfs_MountHFSVolume(struct hfsmount *hfsmp, HFSMasterDirectoryBlock *mdb,
                __unused struct proc *p)
{
        ExtendedVCB *vcb = HFSTOVCB(hfsmp);
        int error;
        ByteCount utf8chars;
        struct cat_desc cndesc;
        struct cat_attr cnattr;
        struct cat_fork fork;
        int newvnode_flags = 0;

        /* Block size must be a multiple of 512 */
        if (SWAP_BE32(mdb->drAlBlkSiz) == 0 ||
            (SWAP_BE32(mdb->drAlBlkSiz) & 0x01FF) != 0)
                return (EINVAL);

        /* don't mount a writeable volume if its dirty, it must be cleaned by fsck_hfs */
        if (((hfsmp->hfs_flags & HFS_READ_ONLY) == 0) &&
            ((SWAP_BE16(mdb->drAtrb) & kHFSVolumeUnmountedMask) == 0)) {
                return (EINVAL);
        }
        hfsmp->hfs_flags |= HFS_STANDARD;
        /*
         * The MDB seems OK: transfer info from it into VCB
         * Note - the VCB starts out clear (all zeros)
         *
         */
        vcb->vcbSigWord         = SWAP_BE16 (mdb->drSigWord);
        vcb->hfs_itime          = to_bsd_time(LocalToUTC(SWAP_BE32(mdb->drCrDate)));
        vcb->localCreateDate    = SWAP_BE32 (mdb->drCrDate);
        vcb->vcbLsMod           = to_bsd_time(LocalToUTC(SWAP_BE32(mdb->drLsMod)));
        vcb->vcbAtrb            = SWAP_BE16 (mdb->drAtrb);
        vcb->vcbNmFls           = SWAP_BE16 (mdb->drNmFls);
        vcb->vcbVBMSt           = SWAP_BE16 (mdb->drVBMSt);
        vcb->nextAllocation     = SWAP_BE16 (mdb->drAllocPtr);
        vcb->totalBlocks        = SWAP_BE16 (mdb->drNmAlBlks);
        vcb->allocLimit         = vcb->totalBlocks;
        vcb->blockSize          = SWAP_BE32 (mdb->drAlBlkSiz);
        vcb->vcbClpSiz          = SWAP_BE32 (mdb->drClpSiz);
        vcb->vcbAlBlSt          = SWAP_BE16 (mdb->drAlBlSt);
        vcb->vcbNxtCNID         = SWAP_BE32 (mdb->drNxtCNID);
        vcb->freeBlocks         = SWAP_BE16 (mdb->drFreeBks);
        vcb->vcbVolBkUp         = to_bsd_time(LocalToUTC(SWAP_BE32(mdb->drVolBkUp)));
        vcb->vcbWrCnt           = SWAP_BE32 (mdb->drWrCnt);
        vcb->vcbNmRtDirs        = SWAP_BE16 (mdb->drNmRtDirs);
        vcb->vcbFilCnt          = SWAP_BE32 (mdb->drFilCnt);
        vcb->vcbDirCnt          = SWAP_BE32 (mdb->drDirCnt);
        bcopy(mdb->drFndrInfo, vcb->vcbFndrInfo, sizeof(vcb->vcbFndrInfo));
        if ((hfsmp->hfs_flags & HFS_READ_ONLY) == 0)
                vcb->vcbWrCnt++;        /* Compensate for write of MDB on last flush */

        /* convert hfs encoded name into UTF-8 string */
        error = hfs_to_utf8(vcb, mdb->drVN, NAME_MAX, &utf8chars, vcb->vcbVN);
        /*
         * When an HFS name cannot be encoded with the current
         * volume encoding we use MacRoman as a fallback.
         */
        if (error || (utf8chars == 0)) {
                error = mac_roman_to_utf8(mdb->drVN, NAME_MAX, &utf8chars, vcb->vcbVN);
                /* If we fail to encode to UTF8 from Mac Roman, the name is bad.  Deny the mount */
                if (error) {
                        goto MtVolErr;
                }
        }

        hfsmp->hfs_logBlockSize = BestBlockSizeFit(vcb->blockSize, MAXBSIZE, hfsmp->hfs_logical_block_size);
        vcb->vcbVBMIOSize = kHFSBlockSize;

        /* Generate the partition-based AVH location */
        hfsmp->hfs_partition_avh_sector = HFS_ALT_SECTOR(hfsmp->hfs_logical_block_size,
                                                  hfsmp->hfs_logical_block_count);
        
        /* HFS standard is read-only, so just stuff the FS location in here, too */
        hfsmp->hfs_fs_avh_sector = hfsmp->hfs_partition_avh_sector;     

        bzero(&cndesc, sizeof(cndesc));
        cndesc.cd_parentcnid = kHFSRootParentID;
        cndesc.cd_flags |= CD_ISMETA;
        bzero(&cnattr, sizeof(cnattr));
        cnattr.ca_linkcount = 1;
        cnattr.ca_mode = S_IFREG;
        bzero(&fork, sizeof(fork));

        /*
         * Set up Extents B-tree vnode
         */
        cndesc.cd_nameptr = hfs_extname;
        cndesc.cd_namelen = strlen((char *)hfs_extname);
        cndesc.cd_cnid = cnattr.ca_fileid = kHFSExtentsFileID;
        fork.cf_size = SWAP_BE32(mdb->drXTFlSize);
        fork.cf_blocks = fork.cf_size / vcb->blockSize;
        fork.cf_clump = SWAP_BE32(mdb->drXTClpSiz);
        fork.cf_vblocks = 0;
        fork.cf_extents[0].startBlock = SWAP_BE16(mdb->drXTExtRec[0].startBlock);
        fork.cf_extents[0].blockCount = SWAP_BE16(mdb->drXTExtRec[0].blockCount);
        fork.cf_extents[1].startBlock = SWAP_BE16(mdb->drXTExtRec[1].startBlock);
        fork.cf_extents[1].blockCount = SWAP_BE16(mdb->drXTExtRec[1].blockCount);
        fork.cf_extents[2].startBlock = SWAP_BE16(mdb->drXTExtRec[2].startBlock);
        fork.cf_extents[2].blockCount = SWAP_BE16(mdb->drXTExtRec[2].blockCount);
        cnattr.ca_blocks = fork.cf_blocks;

        error = hfs_getnewvnode(hfsmp, NULL, NULL, &cndesc, 0, &cnattr, &fork,
                                &hfsmp->hfs_extents_vp, &newvnode_flags);
        if (error) {
                if (HFS_MOUNT_DEBUG) {
                        printf("hfs_mounthfs (std): error creating Ext Vnode (%d) \n", error);
                }
                goto MtVolErr;
        }
        error = MacToVFSError(BTOpenPath(VTOF(hfsmp->hfs_extents_vp),
                                         (KeyCompareProcPtr)CompareExtentKeys));
        if (error) {
                if (HFS_MOUNT_DEBUG) {
                        printf("hfs_mounthfs (std): error opening Ext Vnode (%d) \n", error);
                }
                hfs_unlock(VTOC(hfsmp->hfs_extents_vp));
                goto MtVolErr;
        }
        hfsmp->hfs_extents_cp = VTOC(hfsmp->hfs_extents_vp);

        /*
         * Set up Catalog B-tree vnode...
         */ 
        cndesc.cd_nameptr = hfs_catname;
        cndesc.cd_namelen = strlen((char *)hfs_catname);
        cndesc.cd_cnid = cnattr.ca_fileid = kHFSCatalogFileID;
        fork.cf_size = SWAP_BE32(mdb->drCTFlSize);
        fork.cf_blocks = fork.cf_size / vcb->blockSize;
        fork.cf_clump = SWAP_BE32(mdb->drCTClpSiz);
        fork.cf_vblocks = 0;
        fork.cf_extents[0].startBlock = SWAP_BE16(mdb->drCTExtRec[0].startBlock);
        fork.cf_extents[0].blockCount = SWAP_BE16(mdb->drCTExtRec[0].blockCount);
        fork.cf_extents[1].startBlock = SWAP_BE16(mdb->drCTExtRec[1].startBlock);
        fork.cf_extents[1].blockCount = SWAP_BE16(mdb->drCTExtRec[1].blockCount);
        fork.cf_extents[2].startBlock = SWAP_BE16(mdb->drCTExtRec[2].startBlock);
        fork.cf_extents[2].blockCount = SWAP_BE16(mdb->drCTExtRec[2].blockCount);
        cnattr.ca_blocks = fork.cf_blocks;

        error = hfs_getnewvnode(hfsmp, NULL, NULL, &cndesc, 0, &cnattr, &fork,
                                &hfsmp->hfs_catalog_vp, &newvnode_flags);
        if (error) {
                if (HFS_MOUNT_DEBUG) {
                        printf("hfs_mounthfs (std): error creating catalog Vnode (%d) \n", error);
                }
                hfs_unlock(VTOC(hfsmp->hfs_extents_vp));
                goto MtVolErr;
        }
        error = MacToVFSError(BTOpenPath(VTOF(hfsmp->hfs_catalog_vp),
                                         (KeyCompareProcPtr)CompareCatalogKeys));
        if (error) {
                if (HFS_MOUNT_DEBUG) {
                        printf("hfs_mounthfs (std): error opening catalog Vnode (%d) \n", error);
                }
                hfs_unlock(VTOC(hfsmp->hfs_catalog_vp));
                hfs_unlock(VTOC(hfsmp->hfs_extents_vp));
                goto MtVolErr;
        }
        hfsmp->hfs_catalog_cp = VTOC(hfsmp->hfs_catalog_vp);

        /*
         * Set up dummy Allocation file vnode (used only for locking bitmap)
         */  
        cndesc.cd_nameptr = hfs_vbmname;
        cndesc.cd_namelen = strlen((char *)hfs_vbmname);
        cndesc.cd_cnid = cnattr.ca_fileid = kHFSAllocationFileID;
        bzero(&fork, sizeof(fork));
        cnattr.ca_blocks = 0;

        error = hfs_getnewvnode(hfsmp, NULL, NULL, &cndesc, 0, &cnattr, &fork,
                                 &hfsmp->hfs_allocation_vp, &newvnode_flags);
        if (error) {
                if (HFS_MOUNT_DEBUG) {
                        printf("hfs_mounthfs (std): error creating bitmap Vnode (%d) \n", error);
                }
                hfs_unlock(VTOC(hfsmp->hfs_catalog_vp));
                hfs_unlock(VTOC(hfsmp->hfs_extents_vp));
                goto MtVolErr;
        }
        hfsmp->hfs_allocation_cp = VTOC(hfsmp->hfs_allocation_vp);

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

    if (error == noErr) {
                error = cat_idlookup(hfsmp, kHFSRootFolderID, 0, 0, NULL, NULL, NULL);
                if (HFS_MOUNT_DEBUG) {
                        printf("hfs_mounthfs (std): error looking up root folder (%d) \n", error);
                }
        }
        
    if (error == noErr) {
                /* If the disk isn't write protected.. */
        if ( !(vcb->vcbAtrb & kHFSVolumeHardwareLockMask)) {
            MarkVCBDirty (vcb); //      mark VCB dirty so it will be written
                }
        }
        
        /*
         * all done with system files so we can unlock now...
         */
        hfs_unlock(VTOC(hfsmp->hfs_allocation_vp));
        hfs_unlock(VTOC(hfsmp->hfs_catalog_vp));
        hfs_unlock(VTOC(hfsmp->hfs_extents_vp));
        
        if (error == noErr) {
                /* If successful, then we can just return once we've unlocked the cnodes */
                return error;
        }

    //--        Release any resources allocated so far before exiting with an error:
MtVolErr:
        hfsUnmount(hfsmp, NULL);

    return (error);
}

#endif

//*******************************************************************************
//
// Sanity check Volume Header Block:
//              Input argument *vhp is a pointer to a HFSPlusVolumeHeader block that has
//              not been endian-swapped and represents the on-disk contents of this sector.
//              This routine will not change the endianness of vhp block.
//
//*******************************************************************************
OSErr hfs_ValidateHFSPlusVolumeHeader(struct hfsmount *hfsmp, HFSPlusVolumeHeader *vhp)
{
        u_int16_t signature;
        u_int16_t hfs_version;
        u_int32_t blockSize;

        signature = SWAP_BE16(vhp->signature);
        hfs_version = SWAP_BE16(vhp->version);

        if (signature == kHFSPlusSigWord) {
                if (hfs_version != kHFSPlusVersion) {
                        printf("hfs_ValidateHFSPlusVolumeHeader: invalid HFS+ version: %x\n", hfs_version);
                        return (EINVAL);
                }
        } else if (signature == kHFSXSigWord) {
                if (hfs_version != kHFSXVersion) {
                        printf("hfs_ValidateHFSPlusVolumeHeader: invalid HFSX version: %x\n", hfs_version);
                        return (EINVAL);
                }
        } else {
                /* Removed printf for invalid HFS+ signature because it gives
                 * false error for UFS root volume
                 */
                if (HFS_MOUNT_DEBUG) {
                        printf("hfs_ValidateHFSPlusVolumeHeader: unknown Volume Signature : %x\n", signature);
                }
                return (EINVAL);
        }

        /* Block size must be at least 512 and a power of 2 */
        blockSize = SWAP_BE32(vhp->blockSize);
        if (blockSize < 512 || !powerof2(blockSize)) {
                if (HFS_MOUNT_DEBUG) {
                        printf("hfs_ValidateHFSPlusVolumeHeader: invalid blocksize (%d) \n", blockSize);
                }
                return (EINVAL);
        }

        if (blockSize < hfsmp->hfs_logical_block_size) {
                if (HFS_MOUNT_DEBUG) {
                        printf("hfs_ValidateHFSPlusVolumeHeader: invalid physical blocksize (%d), hfs_logical_blocksize (%d) \n",
                                        blockSize, hfsmp->hfs_logical_block_size);
                }
                return (EINVAL);
        }
        return 0;
}

//*******************************************************************************
//      Routine:        hfs_MountHFSPlusVolume
//
//
//*******************************************************************************

OSErr hfs_MountHFSPlusVolume(struct hfsmount *hfsmp, HFSPlusVolumeHeader *vhp,
        off_t embeddedOffset, u_int64_t disksize, __unused struct proc *p, void *args, kauth_cred_t cred)
{
        register ExtendedVCB *vcb;
        struct cat_desc cndesc;
        struct cat_attr cnattr;
        struct cat_fork cfork;
        u_int32_t blockSize;
        daddr64_t spare_sectors;
        struct BTreeInfoRec btinfo;
        u_int16_t  signature;
        u_int16_t  hfs_version;
        int newvnode_flags = 0;
        int  i;
        OSErr retval;
        char converted_volname[256];
        size_t volname_length = 0;
        size_t conv_volname_length = 0;

        signature = SWAP_BE16(vhp->signature);
        hfs_version = SWAP_BE16(vhp->version);

        retval = hfs_ValidateHFSPlusVolumeHeader(hfsmp, vhp);
        if (retval)
                return retval;

        if (signature == kHFSXSigWord) {
                /* The in-memory signature is always 'H+'. */
                signature = kHFSPlusSigWord;
                hfsmp->hfs_flags |= HFS_X;
        }

        blockSize = SWAP_BE32(vhp->blockSize);
        /* don't mount a writable volume if its dirty, it must be cleaned by fsck_hfs */
        if ((hfsmp->hfs_flags & HFS_READ_ONLY) == 0 && hfsmp->jnl == NULL &&
            (SWAP_BE32(vhp->attributes) & kHFSVolumeUnmountedMask) == 0) {
                if (HFS_MOUNT_DEBUG) {
                        printf("hfs_mounthfsplus: cannot mount dirty non-journaled volumes\n");
                }
                return (EINVAL);
        }

        /* Make sure we can live with the physical block size. */
        if ((disksize & (hfsmp->hfs_logical_block_size - 1)) ||
            (embeddedOffset & (hfsmp->hfs_logical_block_size - 1))) {
                if (HFS_MOUNT_DEBUG) {
                        printf("hfs_mounthfsplus: hfs_logical_blocksize (%d) \n",
                                        hfsmp->hfs_logical_block_size);
                }
                return (ENXIO);
        }

        /*
         * If allocation block size is less than the physical block size,
         * same data could be cached in two places and leads to corruption.
         *
         * 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 to ensure good hfs_physical_block_size is also in
         * hfs_mountfs so that hfs_mountfs, hfs_MountHFSPlusVolume and
         * later are doing the I/Os using same block size.
         */
        if (blockSize < hfsmp->hfs_physical_block_size) {
                hfsmp->hfs_physical_block_size = hfsmp->hfs_logical_block_size;
                hfsmp->hfs_log_per_phys = 1;
        }

        /*
         * The VolumeHeader seems OK: transfer info from it into VCB
         * Note - the VCB starts out clear (all zeros)
         */
        vcb = HFSTOVCB(hfsmp);

        vcb->vcbSigWord = signature;
        vcb->vcbJinfoBlock = SWAP_BE32(vhp->journalInfoBlock);
        vcb->vcbLsMod   = to_bsd_time(SWAP_BE32(vhp->modifyDate));
        vcb->vcbAtrb    = SWAP_BE32(vhp->attributes);
        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);
        
        /* copy 32 bytes of Finder info */
        bcopy(vhp->finderInfo, vcb->vcbFndrInfo, sizeof(vhp->finderInfo));    

        vcb->vcbAlBlSt = 0;             /* hfs+ allocation blocks start at first block of volume */
        if ((hfsmp->hfs_flags & HFS_READ_ONLY) == 0)
                vcb->vcbWrCnt++;        /* compensate for write of Volume Header on last flush */

        /* Now fill in the Extended VCB info */
        vcb->nextAllocation     = SWAP_BE32(vhp->nextAllocation);
        vcb->totalBlocks        = SWAP_BE32(vhp->totalBlocks);
        vcb->allocLimit         = vcb->totalBlocks;
        vcb->freeBlocks         = SWAP_BE32(vhp->freeBlocks);
        vcb->blockSize          = blockSize;
        vcb->encodingsBitmap    = SWAP_BE64(vhp->encodingsBitmap);
        vcb->localCreateDate    = SWAP_BE32(vhp->createDate);
        
        vcb->hfsPlusIOPosOffset = embeddedOffset;

        /* Default to no free block reserve */
        vcb->reserveBlocks = 0;

        /*
         * Update the logical block size in the mount struct
         * (currently set up from the wrapper MDB) using the
         * new blocksize value:
         */
        hfsmp->hfs_logBlockSize = BestBlockSizeFit(vcb->blockSize, MAXBSIZE, hfsmp->hfs_logical_block_size);
        vcb->vcbVBMIOSize = min(vcb->blockSize, MAXPHYSIO);

        /*
         * Validate and initialize the location of the alternate volume header.
         *
         * Note that there may be spare sectors beyond the end of the filesystem that still 
         * belong to our partition. 
         */

        spare_sectors = hfsmp->hfs_logical_block_count -
                        (((daddr64_t)vcb->totalBlocks * blockSize) /
                           hfsmp->hfs_logical_block_size);

        /*
         * Differentiate between "innocuous" spare sectors and the more unusual
         * degenerate case:
         * 
         * *** Innocuous spare sectors exist if:
         * 
         * A) the number of bytes assigned to the partition (by multiplying logical 
         * block size * logical block count) is greater than the filesystem size 
         * (by multiplying allocation block count and allocation block size)
         * 
         * and
         * 
         * B) the remainder is less than the size of a full allocation block's worth of bytes.
         * 
         * This handles the normal case where there may be a few extra sectors, but the two
         * are fundamentally in sync.
         *
         * *** Degenerate spare sectors exist if:
         * A) The number of bytes assigned to the partition (by multiplying logical
         * block size * logical block count) is greater than the filesystem size 
         * (by multiplying allocation block count and block size).
         * 
         * and
         *
         * B) the remainder is greater than a full allocation's block worth of bytes.
         * In this case,  a smaller file system exists in a larger partition.  
         * This can happen in various ways, including when volume is resized but the 
         * partition is yet to be resized.  Under this condition, we have to assume that
         * a partition management software may resize the partition to match 
         * the file system size in the future.  Therefore we should update 
         * alternate volume header at two locations on the disk, 
         *   a. 1024 bytes before end of the partition
         *   b. 1024 bytes before end of the file system 
         */

        if (spare_sectors > (daddr64_t)(blockSize / hfsmp->hfs_logical_block_size)) {
                /* 
                 * Handle the degenerate case above. FS < partition size.
                 * AVH located at 1024 bytes from the end of the partition
                 */
                hfsmp->hfs_partition_avh_sector = (hfsmp->hfsPlusIOPosOffset / hfsmp->hfs_logical_block_size) +
                                           HFS_ALT_SECTOR(hfsmp->hfs_logical_block_size, hfsmp->hfs_logical_block_count);

                /* AVH located at 1024 bytes from the end of the filesystem */
                hfsmp->hfs_fs_avh_sector = (hfsmp->hfsPlusIOPosOffset / hfsmp->hfs_logical_block_size) +
                                           HFS_ALT_SECTOR(hfsmp->hfs_logical_block_size,
                                                (((daddr64_t)vcb->totalBlocks * blockSize) / hfsmp->hfs_logical_block_size));
        } 
        else {
                /* Innocuous spare sectors; Partition & FS notion are in sync */
                hfsmp->hfs_partition_avh_sector = (hfsmp->hfsPlusIOPosOffset / hfsmp->hfs_logical_block_size) +
                                           HFS_ALT_SECTOR(hfsmp->hfs_logical_block_size, hfsmp->hfs_logical_block_count);

                hfsmp->hfs_fs_avh_sector = hfsmp->hfs_partition_avh_sector;
        }
        if (hfs_resize_debug) {
                printf ("hfs_MountHFSPlusVolume: partition_avh_sector=%qu, fs_avh_sector=%qu\n", 
                                hfsmp->hfs_partition_avh_sector, hfsmp->hfs_fs_avh_sector);
        }

        bzero(&cndesc, sizeof(cndesc));
        cndesc.cd_parentcnid = kHFSRootParentID;
        cndesc.cd_flags |= CD_ISMETA;
        bzero(&cnattr, sizeof(cnattr));
        cnattr.ca_linkcount = 1;
        cnattr.ca_mode = S_IFREG;

        /*
         * Set up Extents B-tree vnode
         */
        cndesc.cd_nameptr = hfs_extname;
        cndesc.cd_namelen = strlen((char *)hfs_extname);
        cndesc.cd_cnid = cnattr.ca_fileid = kHFSExtentsFileID;

        cfork.cf_size    = SWAP_BE64 (vhp->extentsFile.logicalSize);
        cfork.cf_new_size= 0;
        cfork.cf_clump   = SWAP_BE32 (vhp->extentsFile.clumpSize);
        cfork.cf_blocks  = SWAP_BE32 (vhp->extentsFile.totalBlocks);
        cfork.cf_vblocks = 0;
        cnattr.ca_blocks = cfork.cf_blocks;
        for (i = 0; i < kHFSPlusExtentDensity; i++) {
                cfork.cf_extents[i].startBlock =
                                SWAP_BE32 (vhp->extentsFile.extents[i].startBlock);
                cfork.cf_extents[i].blockCount =
                                SWAP_BE32 (vhp->extentsFile.extents[i].blockCount);
        }
        retval = hfs_getnewvnode(hfsmp, NULL, NULL, &cndesc, 0, &cnattr, &cfork,
                                 &hfsmp->hfs_extents_vp, &newvnode_flags);
        if (retval)
        {
                if (HFS_MOUNT_DEBUG) {
                        printf("hfs_mounthfsplus: hfs_getnewvnode returned (%d) getting extentoverflow BT\n", retval);
                }
                goto ErrorExit;
        }

        hfsmp->hfs_extents_cp = VTOC(hfsmp->hfs_extents_vp);

        retval = MacToVFSError(BTOpenPath(VTOF(hfsmp->hfs_extents_vp),
                                          (KeyCompareProcPtr) CompareExtentKeysPlus));

        hfs_unlock(hfsmp->hfs_extents_cp);

        if (retval)
        {
                if (HFS_MOUNT_DEBUG) {
                        printf("hfs_mounthfsplus: BTOpenPath returned (%d) getting extentoverflow BT\n", retval);
                }
                goto ErrorExit;
        }
        /*
         * Set up Catalog B-tree vnode
         */ 
        cndesc.cd_nameptr = hfs_catname;
        cndesc.cd_namelen = strlen((char *)hfs_catname);
        cndesc.cd_cnid = cnattr.ca_fileid = kHFSCatalogFileID;

        cfork.cf_size    = SWAP_BE64 (vhp->catalogFile.logicalSize);
        cfork.cf_clump   = SWAP_BE32 (vhp->catalogFile.clumpSize);
        cfork.cf_blocks  = SWAP_BE32 (vhp->catalogFile.totalBlocks);
        cfork.cf_vblocks = 0;
        cnattr.ca_blocks = cfork.cf_blocks;
        for (i = 0; i < kHFSPlusExtentDensity; i++) {
                cfork.cf_extents[i].startBlock =
                                SWAP_BE32 (vhp->catalogFile.extents[i].startBlock);
                cfork.cf_extents[i].blockCount =
                                SWAP_BE32 (vhp->catalogFile.extents[i].blockCount);
        }
        retval = hfs_getnewvnode(hfsmp, NULL, NULL, &cndesc, 0, &cnattr, &cfork,
                                 &hfsmp->hfs_catalog_vp, &newvnode_flags);
        if (retval) {
                if (HFS_MOUNT_DEBUG) {
                        printf("hfs_mounthfsplus: hfs_getnewvnode returned (%d) getting catalog BT\n", retval);
                }
                goto ErrorExit;
        }
        hfsmp->hfs_catalog_cp = VTOC(hfsmp->hfs_catalog_vp);

        retval = MacToVFSError(BTOpenPath(VTOF(hfsmp->hfs_catalog_vp),
                                          (KeyCompareProcPtr) CompareExtendedCatalogKeys));

        if (retval) {
                if (HFS_MOUNT_DEBUG) {
                        printf("hfs_mounthfsplus: BTOpenPath returned (%d) getting catalog BT\n", retval);
                }
                hfs_unlock(hfsmp->hfs_catalog_cp);
                goto ErrorExit;
        }
        if ((hfsmp->hfs_flags & HFS_X) &&
            BTGetInformation(VTOF(hfsmp->hfs_catalog_vp), 0, &btinfo) == 0) {
                if (btinfo.keyCompareType == kHFSBinaryCompare) {
                        hfsmp->hfs_flags |= HFS_CASE_SENSITIVE;
                        /* Install a case-sensitive key compare */
                        (void) BTOpenPath(VTOF(hfsmp->hfs_catalog_vp),
                                          (KeyCompareProcPtr)cat_binarykeycompare);
                }
        }

        hfs_unlock(hfsmp->hfs_catalog_cp);

        /*
         * Set up Allocation file vnode
         */  
        cndesc.cd_nameptr = hfs_vbmname;
        cndesc.cd_namelen = strlen((char *)hfs_vbmname);
        cndesc.cd_cnid = cnattr.ca_fileid = kHFSAllocationFileID;

        cfork.cf_size    = SWAP_BE64 (vhp->allocationFile.logicalSize);
        cfork.cf_clump   = SWAP_BE32 (vhp->allocationFile.clumpSize);
        cfork.cf_blocks  = SWAP_BE32 (vhp->allocationFile.totalBlocks);
        cfork.cf_vblocks = 0;
        cnattr.ca_blocks = cfork.cf_blocks;
        for (i = 0; i < kHFSPlusExtentDensity; i++) {
                cfork.cf_extents[i].startBlock =
                                SWAP_BE32 (vhp->allocationFile.extents[i].startBlock);
                cfork.cf_extents[i].blockCount =
                                SWAP_BE32 (vhp->allocationFile.extents[i].blockCount);
        }
        retval = hfs_getnewvnode(hfsmp, NULL, NULL, &cndesc, 0, &cnattr, &cfork,
                                 &hfsmp->hfs_allocation_vp, &newvnode_flags);
        if (retval) {
                if (HFS_MOUNT_DEBUG) {
                        printf("hfs_mounthfsplus: hfs_getnewvnode returned (%d) getting bitmap\n", retval);
                }
                goto ErrorExit;
        }
        hfsmp->hfs_allocation_cp = VTOC(hfsmp->hfs_allocation_vp);
        hfs_unlock(hfsmp->hfs_allocation_cp);

        /*
         * Set up Attribute B-tree vnode
         */
        if (vhp->attributesFile.totalBlocks != 0) {
                cndesc.cd_nameptr = hfs_attrname;
                cndesc.cd_namelen = strlen((char *)hfs_attrname);
                cndesc.cd_cnid = cnattr.ca_fileid = kHFSAttributesFileID;
        
                cfork.cf_size    = SWAP_BE64 (vhp->attributesFile.logicalSize);
                cfork.cf_clump   = SWAP_BE32 (vhp->attributesFile.clumpSize);
                cfork.cf_blocks  = SWAP_BE32 (vhp->attributesFile.totalBlocks);
                cfork.cf_vblocks = 0;
                cnattr.ca_blocks = cfork.cf_blocks;
                for (i = 0; i < kHFSPlusExtentDensity; i++) {
                        cfork.cf_extents[i].startBlock =
                                        SWAP_BE32 (vhp->attributesFile.extents[i].startBlock);
                        cfork.cf_extents[i].blockCount =
                                        SWAP_BE32 (vhp->attributesFile.extents[i].blockCount);
                }
                retval = hfs_getnewvnode(hfsmp, NULL, NULL, &cndesc, 0, &cnattr, &cfork,
                                         &hfsmp->hfs_attribute_vp, &newvnode_flags);
                if (retval) {
                        if (HFS_MOUNT_DEBUG) {
                                printf("hfs_mounthfsplus: hfs_getnewvnode returned (%d) getting EA BT\n", retval);
                        }
                        goto ErrorExit;
                }
                hfsmp->hfs_attribute_cp = VTOC(hfsmp->hfs_attribute_vp);
                retval = MacToVFSError(BTOpenPath(VTOF(hfsmp->hfs_attribute_vp),
                                                  (KeyCompareProcPtr) hfs_attrkeycompare));
                hfs_unlock(hfsmp->hfs_attribute_cp);
                if (retval) {
                        if (HFS_MOUNT_DEBUG) {
                                printf("hfs_mounthfsplus: BTOpenPath returned (%d) getting EA BT\n", retval);
                        }
                        goto ErrorExit;
                }

                /* Initialize vnode for virtual attribute data file that spans the 
                 * entire file system space for performing I/O to attribute btree
                 * We hold iocount on the attrdata vnode for the entire duration 
                 * of mount (similar to btree vnodes)
                 */
                retval = init_attrdata_vnode(hfsmp);
                if (retval) {
                        if (HFS_MOUNT_DEBUG) {
                                printf("hfs_mounthfsplus: init_attrdata_vnode returned (%d) for virtual EA file\n", retval);
                        }
                        goto ErrorExit;
                }
        }

        /*
         * Set up Startup file vnode
         */
        if (vhp->startupFile.totalBlocks != 0) {
                cndesc.cd_nameptr = hfs_startupname;
                cndesc.cd_namelen = strlen((char *)hfs_startupname);
                cndesc.cd_cnid = cnattr.ca_fileid = kHFSStartupFileID;
        
                cfork.cf_size    = SWAP_BE64 (vhp->startupFile.logicalSize);
                cfork.cf_clump   = SWAP_BE32 (vhp->startupFile.clumpSize);
                cfork.cf_blocks  = SWAP_BE32 (vhp->startupFile.totalBlocks);
                cfork.cf_vblocks = 0;
                cnattr.ca_blocks = cfork.cf_blocks;
                for (i = 0; i < kHFSPlusExtentDensity; i++) {
                        cfork.cf_extents[i].startBlock =
                                        SWAP_BE32 (vhp->startupFile.extents[i].startBlock);
                        cfork.cf_extents[i].blockCount =
                                        SWAP_BE32 (vhp->startupFile.extents[i].blockCount);
                }
                retval = hfs_getnewvnode(hfsmp, NULL, NULL, &cndesc, 0, &cnattr, &cfork,
                                         &hfsmp->hfs_startup_vp, &newvnode_flags);
                if (retval) {
                        if (HFS_MOUNT_DEBUG) {
                                printf("hfs_mounthfsplus: hfs_getnewvnode returned (%d) getting startup file\n", retval);
                        }
                        goto ErrorExit;
                }
                hfsmp->hfs_startup_cp = VTOC(hfsmp->hfs_startup_vp);
                hfs_unlock(hfsmp->hfs_startup_cp);
        }
        
        /* 
         * Pick up volume name and create date 
         *
         * Acquiring the volume name should not manipulate the bitmap, only the catalog
         * btree and possibly the extents overflow b-tree.
         */
        retval = cat_idlookup(hfsmp, kHFSRootFolderID, 0, 0, &cndesc, &cnattr, NULL);
        if (retval) {
                if (HFS_MOUNT_DEBUG) {
                        printf("hfs_mounthfsplus: cat_idlookup returned (%d) getting rootfolder \n", retval);
                }
                goto ErrorExit;
        }
        vcb->hfs_itime = cnattr.ca_itime;
        vcb->volumeNameEncodingHint = cndesc.cd_encoding;
        bcopy(cndesc.cd_nameptr, vcb->vcbVN, min(255, cndesc.cd_namelen));
        volname_length = strlen ((const char*)vcb->vcbVN);
        cat_releasedesc(&cndesc);
        
        /* Send the volume name down to CoreStorage if necessary */     
        retval = utf8_normalizestr(vcb->vcbVN, volname_length, (u_int8_t*)converted_volname, &conv_volname_length, 256, UTF_PRECOMPOSED);
        if (retval == 0) {
                (void) VNOP_IOCTL (hfsmp->hfs_devvp, _DKIOCCSSETLVNAME, converted_volname, 0, vfs_context_current());
        }       
        
        /* reset retval == 0. we don't care about errors in volname conversion */
        retval = 0;

        
        /* 
         * We now always initiate a full bitmap scan even if the volume is read-only because this is 
         * our only shot to do I/Os of dramaticallly different sizes than what the buffer cache ordinarily
         * expects. TRIMs will not be delivered to the underlying media if the volume is not 
         * read-write though.  
         */
        thread_t allocator_scanner;
        hfsmp->scan_var = 0;

        /* Take the HFS mount mutex and wait on scan_var */
        hfs_lock_mount (hfsmp);

        kernel_thread_start ((thread_continue_t) hfs_scan_blocks, hfsmp, &allocator_scanner);

        /* Wait until it registers that it's got the appropriate locks (or that it is finished) */
        while ((hfsmp->scan_var & (HFS_ALLOCATOR_SCAN_INFLIGHT|HFS_ALLOCATOR_SCAN_COMPLETED)) == 0) {
                msleep (&hfsmp->scan_var, &hfsmp->hfs_mutex, PINOD, "hfs_scan_blocks", 0);
        }

        hfs_unlock_mount(hfsmp);

        thread_deallocate (allocator_scanner);

        /* mark the volume dirty (clear clean unmount bit) */
        vcb->vcbAtrb &= ~kHFSVolumeUnmountedMask;
        if (hfsmp->jnl && (hfsmp->hfs_flags & HFS_READ_ONLY) == 0) {
                hfs_flushvolumeheader(hfsmp, HFS_FVH_WAIT);
        }

        /* kHFSHasFolderCount is only supported/updated on HFSX volumes */
        if ((hfsmp->hfs_flags & HFS_X) != 0) {
                hfsmp->hfs_flags |= HFS_FOLDERCOUNT;
        }

        //
        // Check if we need to do late journal initialization.  This only
        // happens if a previous version of MacOS X (or 9) touched the disk.
        // In that case hfs_late_journal_init() will go re-locate the journal 
        // and journal_info_block files and validate that they're still kosher.
        //
        if (   (vcb->vcbAtrb & kHFSVolumeJournaledMask)
                && (SWAP_BE32(vhp->lastMountedVersion) != kHFSJMountVersion)
                && (hfsmp->jnl == NULL)) {

                retval = hfs_late_journal_init(hfsmp, vhp, args);
                if (retval != 0) {
                        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_mounthfsplus: hfs_late_journal_init returned (%d), maybe an external jnl?\n", retval);
                                }
                                retval = EINVAL;
                                goto ErrorExit;
                        }

                        hfsmp->jnl = NULL;
                        
                        // 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 (!(hfsmp->hfs_flags & HFS_READ_ONLY)) {
                                HFSPlusVolumeHeader *jvhp;
                                daddr64_t mdb_offset;
                                struct buf *bp = NULL;
                                
                                hfsmp->hfs_flags |= HFS_NEED_JNL_RESET;
                                    
                                mdb_offset = (daddr64_t)((embeddedOffset / blockSize) + HFS_PRI_SECTOR(blockSize));

                                bp = NULL;
                                retval = (int)buf_meta_bread(hfsmp->hfs_devvp, 
                                                HFS_PHYSBLK_ROUNDDOWN(mdb_offset, hfsmp->hfs_log_per_phys),
                                                hfsmp->hfs_physical_block_size, cred, &bp);
                                if (retval == 0) {
                                        jvhp = (HFSPlusVolumeHeader *)(buf_dataptr(bp) + HFS_PRI_OFFSET(hfsmp->hfs_physical_block_size));
                                            
                                        if (SWAP_BE16(jvhp->signature) == kHFSPlusSigWord || SWAP_BE16(jvhp->signature) == kHFSXSigWord) {
                                                printf ("hfs(3): 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 (HFS_MOUNT_DEBUG) {
                                printf("hfs_mounthfsplus: hfs_late_journal_init returned (%d)\n", retval);
                        }
                        retval = EINVAL;
                        goto ErrorExit;
                } else if (hfsmp->jnl) {
                        vfs_setflags(hfsmp->hfs_mp, (u_int64_t)((unsigned int)MNT_JOURNALED));
                }
        } else if (hfsmp->jnl || ((vcb->vcbAtrb & kHFSVolumeJournaledMask) && (hfsmp->hfs_flags & HFS_READ_ONLY))) {
                struct cat_attr jinfo_attr, jnl_attr;
                
                if (hfsmp->hfs_flags & HFS_READ_ONLY) {
                    vcb->vcbAtrb &= ~kHFSVolumeJournaledMask;
                }

                // if we're here we need to fill in the fileid's for the
                // journal and journal_info_block.
                hfsmp->hfs_jnlinfoblkid = GetFileInfo(vcb, kRootDirID, ".journal_info_block", &jinfo_attr, NULL);
                hfsmp->hfs_jnlfileid    = GetFileInfo(vcb, kRootDirID, ".journal", &jnl_attr, NULL);
                if (hfsmp->hfs_jnlinfoblkid == 0 || hfsmp->hfs_jnlfileid == 0) {
                        printf("hfs: danger! couldn't find the file-id's for the journal or journal_info_block\n");
                        printf("hfs: jnlfileid %d, jnlinfoblkid %d\n", hfsmp->hfs_jnlfileid, hfsmp->hfs_jnlinfoblkid);
                }

                if (hfsmp->hfs_flags & HFS_READ_ONLY) {
                    vcb->vcbAtrb |= kHFSVolumeJournaledMask;
                }

                if (hfsmp->jnl == NULL) {
                    vfs_clearflags(hfsmp->hfs_mp, (u_int64_t)((unsigned int)MNT_JOURNALED));
                }
        }

        if ( !(vcb->vcbAtrb & kHFSVolumeHardwareLockMask) )     // if the disk is not write protected
        {
                MarkVCBDirty( vcb );    // mark VCB dirty so it will be written
        }

        if (hfsmp->hfs_flags & HFS_CS_METADATA_PIN) {
                hfs_pin_fs_metadata(hfsmp);
        }
        /*
         * Distinguish 3 potential cases involving content protection:
         * 1. mount point bit set; vcbAtrb does not support it. Fail.
         * 2. mount point bit set; vcbattrb supports it. we're good.
         * 3. mount point bit not set; vcbatrb supports it, turn bit on, then good.
         */
        if (vfs_flags(hfsmp->hfs_mp) & MNT_CPROTECT) {
                /* Does the mount point support it ? */
                if ((vcb->vcbAtrb & kHFSContentProtectionMask) == 0) {
                        /* Case 1 above */
                        retval = EINVAL;
                        goto ErrorExit;
                }
        }
        else {
                /* not requested in the mount point. Is it in FS? */
                if (vcb->vcbAtrb & kHFSContentProtectionMask) {
                        /* Case 3 above */
                        vfs_setflags (hfsmp->hfs_mp, MNT_CPROTECT);
                }
        }

        /* At this point, if the mount point flag is set, we can enable it. */
        if (vfs_flags(hfsmp->hfs_mp) & MNT_CPROTECT) {
                /* Cases 2+3 above */
#if CONFIG_PROTECT
                /* Get the EAs as needed. */
                int cperr = 0;
                struct cp_root_xattr *xattr = NULL;
                xattr = hfs_malloc(sizeof(*xattr));

                /* go get the EA to get the version information */
                cperr = cp_getrootxattr (hfsmp, xattr);
                /* 
                 * If there was no EA there, then write one out. 
                 * Assuming EA is not present on the root means 
                 * this is an erase install or a very old FS
                 */

                if (cperr == 0) {
                        /* Have to run a valid CP version. */
                        if (!cp_is_supported_version(xattr->major_version)) {
                                cperr = EINVAL;
                        }
                }
                else if (cperr == ENOATTR) {
                        printf("No root EA set, creating new EA with new version: %d\n", CP_CURRENT_VERS);
                        bzero(xattr, sizeof(struct cp_root_xattr));
                        xattr->major_version = CP_CURRENT_VERS;
                        xattr->minor_version = CP_MINOR_VERS;
                        cperr = cp_setrootxattr (hfsmp, xattr);
                }

                if (cperr) {
                        hfs_free(xattr, sizeof(*xattr));
                        retval = EPERM;
                        goto ErrorExit;
                }

                /* If we got here, then the CP version is valid. Set it in the mount point */
                hfsmp->hfs_running_cp_major_vers = xattr->major_version;
                printf("Running with CP root xattr: %d.%d\n", xattr->major_version, xattr->minor_version);
                hfsmp->cproot_flags = xattr->flags;
                hfsmp->cp_crypto_generation = ISSET(xattr->flags, CP_ROOT_CRYPTOG1) ? 1 : 0;
#if HFS_CONFIG_KEY_ROLL
                hfsmp->hfs_auto_roll_min_key_os_version = xattr->auto_roll_min_version;
                hfsmp->hfs_auto_roll_max_key_os_version = xattr->auto_roll_max_version;
#endif

                hfs_free(xattr, sizeof(*xattr));

                /*
                 * Acquire the boot-arg for the AKS default key; if invalid, obtain from the device tree.
                 * Ensure that the boot-arg's value is valid for FILES (not directories),
                 * since only files are actually protected for now.
                 */

                PE_parse_boot_argn("aks_default_class", &hfsmp->default_cp_class, sizeof(hfsmp->default_cp_class));

                if (cp_is_valid_class(0, hfsmp->default_cp_class) == 0) {
                        PE_get_default("kern.default_cp_class", &hfsmp->default_cp_class, sizeof(hfsmp->default_cp_class));
                }

#if HFS_TMPDBG
#if !SECURE_KERNEL
                PE_parse_boot_argn("aks_verbose", &hfsmp->hfs_cp_verbose, sizeof(hfsmp->hfs_cp_verbose));
#endif
#endif

                if (cp_is_valid_class(0, hfsmp->default_cp_class) == 0) {
                        hfsmp->default_cp_class = PROTECTION_CLASS_C;
                }

#else
                /* If CONFIG_PROTECT not built, ignore CP */
                vfs_clearflags(hfsmp->hfs_mp, MNT_CPROTECT);    
#endif
        }

        /*
         * Establish a metadata allocation zone.
         */
        hfs_metadatazone_init(hfsmp, false);

        /*
         * Make any metadata zone adjustments.
         */
        if (hfsmp->hfs_flags & HFS_METADATA_ZONE) {
                /* Keep the roving allocator out of the metadata zone. */
                if (vcb->nextAllocation >= hfsmp->hfs_metazone_start &&
                    vcb->nextAllocation <= hfsmp->hfs_metazone_end) {       
                        HFS_UPDATE_NEXT_ALLOCATION(hfsmp, hfsmp->hfs_metazone_end + 1);
                }
        } else {
                if (vcb->nextAllocation <= 1) {
                        vcb->nextAllocation = hfsmp->hfs_min_alloc_start;
                }
        }
        vcb->sparseAllocation = hfsmp->hfs_min_alloc_start;

        /* Setup private/hidden directories for hardlinks. */
        hfs_privatedir_init(hfsmp, FILE_HARDLINKS);
        hfs_privatedir_init(hfsmp, DIR_HARDLINKS);

        if ((hfsmp->hfs_flags & HFS_READ_ONLY) == 0) 
                hfs_remove_orphans(hfsmp);

        /* See if we need to erase unused Catalog nodes due to <rdar://problem/6947811>. */
        if ((hfsmp->hfs_flags & HFS_READ_ONLY) == 0)
        {
                retval = hfs_erase_unused_nodes(hfsmp);
                if (retval) {
                        if (HFS_MOUNT_DEBUG) {
                                printf("hfs_mounthfsplus: hfs_erase_unused_nodes returned (%d) for %s \n", retval, hfsmp->vcbVN);
                        }

                        goto ErrorExit;
                }
        }
                
        /*
         * Allow hot file clustering if conditions allow.
         */
        if ((hfsmp->hfs_flags & HFS_METADATA_ZONE)  && !(hfsmp->hfs_flags & HFS_READ_ONLY) &&
            ((hfsmp->hfs_flags & HFS_SSD) == 0 || (hfsmp->hfs_flags & HFS_CS_HOTFILE_PIN))) {
                //
                // Wait until the bitmap scan completes before we initializes the
                // hotfile area so that we do not run into any issues with the
                // bitmap being read while hotfiles is initializing itself.  On
                // some older/slower machines, without this interlock, the bitmap
                // would sometimes get corrupted at boot time.
                //
                hfs_lock_mount(hfsmp);
                while(!(hfsmp->scan_var & HFS_ALLOCATOR_SCAN_COMPLETED)) {
                        (void) msleep (&hfsmp->scan_var, &hfsmp->hfs_mutex, PINOD, "hfs_hotfile_bitmap_interlock", 0);
                }
                hfs_unlock_mount(hfsmp);
                
                /*
                 * 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.
                 */
                (void) hfs_recording_init(hfsmp);
        }

        /* Force ACLs on HFS+ file systems. */
        vfs_setextendedsecurity(HFSTOVFS(hfsmp));

        /* Enable extent-based extended attributes by default */
        hfsmp->hfs_flags |= HFS_XATTR_EXTENTS;

        return (0);

ErrorExit:
        /*
         * A fatal error occurred and the volume cannot be mounted, so 
         * release any resources that we acquired...
         */
        hfsUnmount(hfsmp, NULL);
                
        if (HFS_MOUNT_DEBUG) {
                printf("hfs_mounthfsplus: encountered error (%d)\n", retval);
        }
        return (retval);
}

static int
_pin_metafile(struct hfsmount *hfsmp, vnode_t vp)
{
        int err;

        err = hfs_lock(VTOC(vp), HFS_SHARED_LOCK, HFS_LOCK_DEFAULT);
        if (err == 0) {
                err = hfs_pin_vnode(hfsmp, vp, HFS_PIN_IT, NULL);
                hfs_unlock(VTOC(vp));
        }

        return err;
}

void
hfs_pin_fs_metadata(struct hfsmount *hfsmp)
{
        ExtendedVCB *vcb;
        int err;
        
        vcb = HFSTOVCB(hfsmp);

        err = _pin_metafile(hfsmp, hfsmp->hfs_extents_vp);
        if (err != 0) {
                printf("hfs: failed to pin extents overflow file %d\n", err);
        }                               
        err = _pin_metafile(hfsmp, hfsmp->hfs_catalog_vp);
        if (err != 0) {
                printf("hfs: failed to pin catalog file %d\n", err);
        }                               
        err = _pin_metafile(hfsmp, hfsmp->hfs_allocation_vp);
        if (err != 0) {
                printf("hfs: failed to pin bitmap file %d\n", err);
        }                               
        err = _pin_metafile(hfsmp, hfsmp->hfs_attribute_vp);
        if (err != 0) {
                printf("hfs: failed to pin extended attr file %d\n", err);
        }                               
        
        hfs_pin_block_range(hfsmp, HFS_PIN_IT, 0, 1);
        hfs_pin_block_range(hfsmp, HFS_PIN_IT, vcb->totalBlocks-1, 1);
                        
        if (vfs_flags(hfsmp->hfs_mp) & MNT_JOURNALED) {
                // and hey, if we've got a journal, let's pin that too!
                hfs_pin_block_range(hfsmp, HFS_PIN_IT, hfsmp->jnl_start, howmany(hfsmp->jnl_size, vcb->blockSize));
        }
}

/*
 * ReleaseMetaFileVNode
 *
 * vp   L - -
 */
static void ReleaseMetaFileVNode(struct vnode *vp)
{
        struct filefork *fp;

        if (vp && (fp = VTOF(vp))) {
                if (fp->fcbBTCBPtr != NULL) {
                        (void)hfs_lock(VTOC(vp), HFS_EXCLUSIVE_LOCK, HFS_LOCK_DEFAULT);
                        (void) BTClosePath(fp);
                        hfs_unlock(VTOC(vp));
                }

                /* release the node even if BTClosePath fails */
                vnode_recycle(vp);
                vnode_put(vp);
        }
}


/*************************************************************
*
* Unmounts a hfs volume.
*       At this point vflush() has been called (to dump all non-metadata files)
*
*************************************************************/

int
hfsUnmount( register struct hfsmount *hfsmp, __unused struct proc *p)
{
        /* Get rid of our attribute data vnode (if any).  This is done 
         * after the vflush() during mount, so we don't need to worry 
         * about any locks.
         */
        if (hfsmp->hfs_attrdata_vp) {
                ReleaseMetaFileVNode(hfsmp->hfs_attrdata_vp);
                hfsmp->hfs_attrdata_vp = NULLVP;
        }

        if (hfsmp->hfs_startup_vp) {
                ReleaseMetaFileVNode(hfsmp->hfs_startup_vp);
                hfsmp->hfs_startup_cp = NULL;
                hfsmp->hfs_startup_vp = NULL;
        }
        
        if (hfsmp->hfs_attribute_vp) {
                ReleaseMetaFileVNode(hfsmp->hfs_attribute_vp);
                hfsmp->hfs_attribute_cp = NULL;
                hfsmp->hfs_attribute_vp = NULL;
        }

        if (hfsmp->hfs_catalog_vp) {
                ReleaseMetaFileVNode(hfsmp->hfs_catalog_vp);
                hfsmp->hfs_catalog_cp = NULL;
                hfsmp->hfs_catalog_vp = NULL;
        }

        if (hfsmp->hfs_extents_vp) {
                ReleaseMetaFileVNode(hfsmp->hfs_extents_vp);
                hfsmp->hfs_extents_cp = NULL;
                hfsmp->hfs_extents_vp = NULL;
        }

        if (hfsmp->hfs_allocation_vp) {
                ReleaseMetaFileVNode(hfsmp->hfs_allocation_vp);
                hfsmp->hfs_allocation_cp = NULL;
                hfsmp->hfs_allocation_vp = NULL;
        }

        return (0);
}


/*
 * Test if fork has overflow extents.
 *
 * Returns: 
 *      non-zero - overflow extents exist
 *      zero     - overflow extents do not exist 
 */
bool overflow_extents(struct filefork *fp)
{
        u_int32_t blocks;

        //
        // If the vnode pointer is NULL then we're being called
        // from hfs_remove_orphans() with a faked-up filefork
        // and therefore it has to be an HFS+ volume.  Otherwise
        // we check through the volume header to see what type
        // of volume we're on.
        //

#if CONFIG_HFS_STD
        if (FTOV(fp) && VTOVCB(FTOV(fp))->vcbSigWord == kHFSSigWord) {
                if (fp->ff_extents[2].blockCount == 0)
                        return false;

                blocks = fp->ff_extents[0].blockCount +
                        fp->ff_extents[1].blockCount +
                        fp->ff_extents[2].blockCount;   

                return fp->ff_blocks > blocks;
        }
#endif

        if (fp->ff_extents[7].blockCount == 0)
                return false;

        blocks = fp->ff_extents[0].blockCount +
                fp->ff_extents[1].blockCount +
                fp->ff_extents[2].blockCount +
                fp->ff_extents[3].blockCount +
                fp->ff_extents[4].blockCount +
                fp->ff_extents[5].blockCount +
                fp->ff_extents[6].blockCount +
                fp->ff_extents[7].blockCount;   

        return fp->ff_blocks > blocks;
}

static __attribute__((pure))
boolean_t hfs_is_frozen(struct hfsmount *hfsmp)
{
        return (hfsmp->hfs_freeze_state == HFS_FROZEN
                        || (hfsmp->hfs_freeze_state == HFS_FREEZING
                                && current_thread() != hfsmp->hfs_freezing_thread));
}

/*
 * Lock the HFS global journal lock 
 */
int 
hfs_lock_global (struct hfsmount *hfsmp, enum hfs_locktype locktype) 
{
        thread_t thread = current_thread();

        if (hfsmp->hfs_global_lockowner == thread) {
                panic ("hfs_lock_global: locking against myself!");
        }

        /*
         * This check isn't really necessary but this stops us taking
         * the mount lock in most cases.  The essential check is below.
         */
        if (hfs_is_frozen(hfsmp)) {
                /*
                 * Unfortunately, there is no easy way of getting a notification
                 * for when a process is exiting and it's possible for the exiting 
                 * process to get blocked somewhere else.  To catch this, we
                 * periodically monitor the frozen process here and thaw if
                 * we spot that it's exiting.
                 */
frozen:
                hfs_lock_mount(hfsmp);

                struct timespec ts = { 0, 500 * NSEC_PER_MSEC };

                while (hfs_is_frozen(hfsmp)) {
                        if (hfsmp->hfs_freeze_state == HFS_FROZEN
                                && proc_exiting(hfsmp->hfs_freezing_proc)) {
                                hfs_thaw_locked(hfsmp);
                                break;
                        }

                        msleep(&hfsmp->hfs_freeze_state, &hfsmp->hfs_mutex,
                               PWAIT, "hfs_lock_global (frozen)", &ts);
                }
                hfs_unlock_mount(hfsmp);
        }

        /* HFS_SHARED_LOCK */
        if (locktype == HFS_SHARED_LOCK) {
                lck_rw_lock_shared (&hfsmp->hfs_global_lock);
                hfsmp->hfs_global_lockowner = HFS_SHARED_OWNER;
        }
        /* HFS_EXCLUSIVE_LOCK */
        else {
                lck_rw_lock_exclusive (&hfsmp->hfs_global_lock);
                hfsmp->hfs_global_lockowner = thread;
        }

        /* 
         * We have to check if we're frozen again because of the time
         * between when we checked and when we took the global lock.
         */
        if (hfs_is_frozen(hfsmp)) {
                hfs_unlock_global(hfsmp);
                goto frozen;
        }

        return 0;
}


/*
 * Unlock the HFS global journal lock
 */
void 
hfs_unlock_global (struct hfsmount *hfsmp) 
{       
        thread_t thread = current_thread();

        /* HFS_LOCK_EXCLUSIVE */
        if (hfsmp->hfs_global_lockowner == thread) {
                hfsmp->hfs_global_lockowner = NULL;
                lck_rw_unlock_exclusive (&hfsmp->hfs_global_lock);
        }
        /* HFS_LOCK_SHARED */
        else {
                lck_rw_unlock_shared (&hfsmp->hfs_global_lock);
        }
}

/*
 * Lock the HFS mount lock
 * 
 * Note: this is a mutex, not a rw lock! 
 */
inline 
void hfs_lock_mount (struct hfsmount *hfsmp) {
        lck_mtx_lock (&(hfsmp->hfs_mutex)); 
}

/*
 * Unlock the HFS mount lock
 *
 * Note: this is a mutex, not a rw lock! 
 */
inline
void hfs_unlock_mount (struct hfsmount *hfsmp) {
        lck_mtx_unlock (&(hfsmp->hfs_mutex));
}

/*
 * Lock HFS system file(s).
 *
 * This function accepts a @flags parameter which indicates which
 * system file locks are required.  The value it returns should be
 * used in a subsequent call to hfs_systemfile_unlock.  The caller
 * should treat this value as opaque; it may or may not have a
 * relation to the @flags field that is passed in.  The *only*
 * guarantee that we make is that a value of zero means that no locks
 * were taken and that there is no need to call hfs_systemfile_unlock
 * (although it is harmless to do so).  Recursion is supported but
 * care must still be taken to ensure correct lock ordering.  Note
 * that requests for certain locks may cause other locks to also be
 * taken, including locks that are not possible to ask for via the
 * @flags parameter.
 */
int
hfs_systemfile_lock(struct hfsmount *hfsmp, int flags, enum hfs_locktype locktype)
{
        /*
         * Locking order is Catalog file, Attributes file, Startup file, Bitmap file, Extents file
         */
        if (flags & SFL_CATALOG) {
                if (hfsmp->hfs_catalog_cp
                        && hfsmp->hfs_catalog_cp->c_lockowner != current_thread()) {
#ifdef HFS_CHECK_LOCK_ORDER
                        if (hfsmp->hfs_attribute_cp && hfsmp->hfs_attribute_cp->c_lockowner == current_thread()) {
                                panic("hfs_systemfile_lock: bad lock order (Attributes before Catalog)");
                        }
                        if (hfsmp->hfs_startup_cp && hfsmp->hfs_startup_cp->c_lockowner == current_thread()) {
                                panic("hfs_systemfile_lock: bad lock order (Startup before Catalog)");
                        }
                        if (hfsmp-> hfs_extents_cp && hfsmp->hfs_extents_cp->c_lockowner == current_thread()) {
                                panic("hfs_systemfile_lock: bad lock order (Extents before Catalog)");
                        }
#endif /* HFS_CHECK_LOCK_ORDER */

                        (void) hfs_lock(hfsmp->hfs_catalog_cp, locktype, HFS_LOCK_DEFAULT);
                        /*
                         * When the catalog file has overflow extents then
                         * also acquire the extents b-tree lock if its not
                         * already requested.
                         */
                        if (((flags & SFL_EXTENTS) == 0) &&
                            (hfsmp->hfs_catalog_vp != NULL) && 
                            (overflow_extents(VTOF(hfsmp->hfs_catalog_vp)))) {
                                flags |= SFL_EXTENTS;
                        }
                } else {
                        flags &= ~SFL_CATALOG;
                }
        }

        if (flags & SFL_ATTRIBUTE) {
                if (hfsmp->hfs_attribute_cp
                        && hfsmp->hfs_attribute_cp->c_lockowner != current_thread()) {
#ifdef HFS_CHECK_LOCK_ORDER
                        if (hfsmp->hfs_startup_cp && hfsmp->hfs_startup_cp->c_lockowner == current_thread()) {
                                panic("hfs_systemfile_lock: bad lock order (Startup before Attributes)");
                        }
                        if (hfsmp->hfs_extents_cp && hfsmp->hfs_extents_cp->c_lockowner == current_thread()) {
                                panic("hfs_systemfile_lock: bad lock order (Extents before Attributes)");
                        }
#endif /* HFS_CHECK_LOCK_ORDER */
                        
                        (void) hfs_lock(hfsmp->hfs_attribute_cp, locktype, HFS_LOCK_DEFAULT);
                        /*
                         * When the attribute file has overflow extents then
                         * also acquire the extents b-tree lock if its not
                         * already requested.
                         */
                        if (((flags & SFL_EXTENTS) == 0) &&
                            (hfsmp->hfs_attribute_vp != NULL) &&
                            (overflow_extents(VTOF(hfsmp->hfs_attribute_vp)))) {
                                flags |= SFL_EXTENTS;
                        }
                } else {
                        flags &= ~SFL_ATTRIBUTE;
                }
        }

        if (flags & SFL_STARTUP) {
                if (hfsmp->hfs_startup_cp
                        && hfsmp->hfs_startup_cp->c_lockowner != current_thread()) {
#ifdef HFS_CHECK_LOCK_ORDER
                        if (hfsmp-> hfs_extents_cp && hfsmp->hfs_extents_cp->c_lockowner == current_thread()) {
                                panic("hfs_systemfile_lock: bad lock order (Extents before Startup)");
                        }
#endif /* HFS_CHECK_LOCK_ORDER */

                        (void) hfs_lock(hfsmp->hfs_startup_cp, locktype, HFS_LOCK_DEFAULT);
                        /*
                         * When the startup file has overflow extents then
                         * also acquire the extents b-tree lock if its not
                         * already requested.
                         */
                        if (((flags & SFL_EXTENTS) == 0) &&
                            (hfsmp->hfs_startup_vp != NULL) &&
                            (overflow_extents(VTOF(hfsmp->hfs_startup_vp)))) {
                                flags |= SFL_EXTENTS;
                        }
                } else {
                        flags &= ~SFL_STARTUP;
                }
        }

        /* 
         * To prevent locks being taken in the wrong order, the extent lock
         * gets a bitmap lock as well.
         */
        if (flags & (SFL_BITMAP | SFL_EXTENTS)) {
                if (hfsmp->hfs_allocation_cp) {
                        (void) hfs_lock(hfsmp->hfs_allocation_cp, HFS_EXCLUSIVE_LOCK, HFS_LOCK_DEFAULT);
                        /* 
                         * The bitmap lock is also grabbed when only extent lock 
                         * was requested. Set the bitmap lock bit in the lock
                         * flags which callers will use during unlock.
                         */
                        flags |= SFL_BITMAP;
                } else {
                        flags &= ~SFL_BITMAP;
                }
        }

        if (flags & SFL_EXTENTS) {
                /*
                 * Since the extents btree lock is recursive we always
                 * need exclusive access.
                 */
                if (hfsmp->hfs_extents_cp) {
                        (void) hfs_lock(hfsmp->hfs_extents_cp, HFS_EXCLUSIVE_LOCK, HFS_LOCK_DEFAULT);

                        if (vfs_isswapmount(hfsmp->hfs_mp)) {
                                /*
                                 * because we may need this lock on the pageout path (if a swapfile allocation
                                 * spills into the extents overflow tree), we will grant the holder of this
                                 * lock the privilege of dipping into the reserve free pool in order to prevent
                                 * a deadlock from occurring if we need those pageouts to complete before we
                                 * will make any new pages available on the free list... the deadlock can occur
                                 * if this thread needs to allocate memory while this lock is held
                                 */
                                if (set_vm_privilege(TRUE) == FALSE) {
                                        /*
                                         * indicate that we need to drop vm_privilege 
                                         * when we unlock
                                         */
                                        flags |= SFL_VM_PRIV;
                                }
                        }
                } else {
                        flags &= ~SFL_EXTENTS;
                }
        }

        return (flags);
}

/*
 * unlock HFS system file(s).
 */
void
hfs_systemfile_unlock(struct hfsmount *hfsmp, int flags)
{
        if (!flags)
                return;

        struct timeval tv;
        u_int32_t lastfsync;
        int numOfLockedBuffs;

        if (hfsmp->jnl == NULL) {
                microuptime(&tv);
                lastfsync = tv.tv_sec;
        }
        if (flags & SFL_STARTUP && hfsmp->hfs_startup_cp) {
                hfs_unlock(hfsmp->hfs_startup_cp);
        }
        if (flags & SFL_ATTRIBUTE && hfsmp->hfs_attribute_cp) {
                if (hfsmp->jnl == NULL) {
                        BTGetLastSync((FCB*)VTOF(hfsmp->hfs_attribute_vp), &lastfsync);
                        numOfLockedBuffs = count_lock_queue();
                        if ((numOfLockedBuffs > kMaxLockedMetaBuffers) ||
                            ((numOfLockedBuffs > 1) && ((tv.tv_sec - lastfsync) >
                              kMaxSecsForFsync))) {
                                hfs_btsync(hfsmp->hfs_attribute_vp, HFS_SYNCTRANS);
                        }
                }
                hfs_unlock(hfsmp->hfs_attribute_cp);
        }
        if (flags & SFL_CATALOG && hfsmp->hfs_catalog_cp) {
                if (hfsmp->jnl == NULL) {
                        BTGetLastSync((FCB*)VTOF(hfsmp->hfs_catalog_vp), &lastfsync);
                        numOfLockedBuffs = count_lock_queue();
                        if ((numOfLockedBuffs > kMaxLockedMetaBuffers) ||
                            ((numOfLockedBuffs > 1) && ((tv.tv_sec - lastfsync) >
                              kMaxSecsForFsync))) {
                                hfs_btsync(hfsmp->hfs_catalog_vp, HFS_SYNCTRANS);
                        }
                }
                hfs_unlock(hfsmp->hfs_catalog_cp);
        }
        if (flags & SFL_BITMAP && hfsmp->hfs_allocation_cp) {
                hfs_unlock(hfsmp->hfs_allocation_cp);
        }
        if (flags & SFL_EXTENTS && hfsmp->hfs_extents_cp) {
                if (hfsmp->jnl == NULL) {
                        BTGetLastSync((FCB*)VTOF(hfsmp->hfs_extents_vp), &lastfsync);
                        numOfLockedBuffs = count_lock_queue();
                        if ((numOfLockedBuffs > kMaxLockedMetaBuffers) ||
                            ((numOfLockedBuffs > 1) && ((tv.tv_sec - lastfsync) >
                              kMaxSecsForFsync))) {
                                hfs_btsync(hfsmp->hfs_extents_vp, HFS_SYNCTRANS);
                        }
                }
                hfs_unlock(hfsmp->hfs_extents_cp);

                if (flags & SFL_VM_PRIV) {
                        /*
                         * revoke the vm_privilege we granted this thread
                         * now that we have unlocked the overflow extents
                         */
                        set_vm_privilege(FALSE);
                }
        }
}


/*
 * RequireFileLock
 *
 * Check to see if a vnode is locked in the current context
 * This is to be used for debugging purposes only!!
 */
#if DEBUG
void RequireFileLock(FileReference vp, int shareable)
{
        int locked;

        /* The extents btree and allocation bitmap are always exclusive. */
        if (VTOC(vp)->c_fileid == kHFSExtentsFileID ||
            VTOC(vp)->c_fileid == kHFSAllocationFileID) {
                shareable = 0;
        }
        
        locked = VTOC(vp)->c_lockowner == current_thread();
        
        if (!locked && !shareable) {
                switch (VTOC(vp)->c_fileid) {
                case kHFSExtentsFileID:
                        panic("hfs: extents btree not locked! v: 0x%08X\n #\n", (u_int)vp);
                        break;
                case kHFSCatalogFileID:
                        panic("hfs: catalog btree not locked! v: 0x%08X\n #\n", (u_int)vp);
                        break;
                case kHFSAllocationFileID:
                        /* The allocation file can hide behind the jornal lock. */
                        if (VTOHFS(vp)->jnl == NULL)
                                panic("hfs: allocation file not locked! v: 0x%08X\n #\n", (u_int)vp);
                        break;
                case kHFSStartupFileID:
                        panic("hfs: startup file not locked! v: 0x%08X\n #\n", (u_int)vp);
                case kHFSAttributesFileID:
                        panic("hfs: attributes btree not locked! v: 0x%08X\n #\n", (u_int)vp);
                        break;
                }
        }
}
#endif // DEBUG


/*
 * There are three ways to qualify for ownership rights on an object:
 *
 * 1. (a) Your UID matches the cnode's UID.
 *    (b) The object in question is owned by "unknown"
 * 2. (a) Permissions on the filesystem are being ignored and
 *        your UID matches the replacement UID.
 *    (b) Permissions on the filesystem are being ignored and
 *        the replacement UID is "unknown".
 * 3. You are root.
 *
 */
int
hfs_owner_rights(struct hfsmount *hfsmp, uid_t cnode_uid, kauth_cred_t cred,
                __unused struct proc *p, int invokesuperuserstatus)
{
        if ((kauth_cred_getuid(cred) == cnode_uid) ||                                    /* [1a] */
            (cnode_uid == UNKNOWNUID) ||                                                                          /* [1b] */
            ((((unsigned int)vfs_flags(HFSTOVFS(hfsmp))) & MNT_UNKNOWNPERMISSIONS) &&          /* [2] */
              ((kauth_cred_getuid(cred) == hfsmp->hfs_uid) ||                            /* [2a] */
                (hfsmp->hfs_uid == UNKNOWNUID))) ||                           /* [2b] */
            (invokesuperuserstatus && (suser(cred, 0) == 0))) {    /* [3] */
                return (0);
        } else {        
                return (EPERM);
        }
}


u_int32_t BestBlockSizeFit(u_int32_t allocationBlockSize,
                               u_int32_t blockSizeLimit,
                               u_int32_t baseMultiple) {
    /*
       Compute the optimal (largest) block size (no larger than allocationBlockSize) that is less than the
       specified limit but still an even multiple of the baseMultiple.
     */
    int baseBlockCount, blockCount;
    u_int32_t trialBlockSize;

    if (allocationBlockSize % baseMultiple != 0) {
        /*
           Whoops: the allocation blocks aren't even multiples of the specified base:
           no amount of dividing them into even parts will be a multiple, either then!
        */
        return 512;             /* Hope for the best */
    };

    /* Try the obvious winner first, to prevent 12K allocation blocks, for instance,
       from being handled as two 6K logical blocks instead of 3 4K logical blocks.
       Even though the former (the result of the loop below) is the larger allocation
       block size, the latter is more efficient: */
    if (allocationBlockSize % PAGE_SIZE == 0) return PAGE_SIZE;

    /* No clear winner exists: pick the largest even fraction <= MAXBSIZE: */
    baseBlockCount = allocationBlockSize / baseMultiple;                                /* Now guaranteed to be an even multiple */

    for (blockCount = baseBlockCount; blockCount > 0; --blockCount) {
        trialBlockSize = blockCount * baseMultiple;
        if (allocationBlockSize % trialBlockSize == 0) {                                /* An even multiple? */
            if ((trialBlockSize <= blockSizeLimit) &&
                (trialBlockSize % baseMultiple == 0)) {
                return trialBlockSize;
            };
        };
    };

    /* Note: we should never get here, since blockCount = 1 should always work,
       but this is nice and safe and makes the compiler happy, too ... */
    return 512;
}


u_int32_t
GetFileInfo(ExtendedVCB *vcb, __unused u_int32_t dirid, const char *name,
                        struct cat_attr *fattr, struct cat_fork *forkinfo)
{
        struct hfsmount * hfsmp;
        struct cat_desc jdesc;
        int lockflags;
        int error;
        
        if (vcb->vcbSigWord != kHFSPlusSigWord)
                return (0);

        hfsmp = VCBTOHFS(vcb);

        memset(&jdesc, 0, sizeof(struct cat_desc));
        jdesc.cd_parentcnid = kRootDirID;
        jdesc.cd_nameptr = (const u_int8_t *)name;
        jdesc.cd_namelen = strlen(name);

        lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG, HFS_SHARED_LOCK);
        error = cat_lookup(hfsmp, &jdesc, 0, 0, NULL, fattr, forkinfo, NULL);
        hfs_systemfile_unlock(hfsmp, lockflags);

        if (error == 0) {
                return (fattr->ca_fileid);
        } else if (hfsmp->hfs_flags & HFS_READ_ONLY) {
                return (0);
        }

        return (0);     /* XXX what callers expect on an error */
}


/*
 * On HFS Plus Volumes, there can be orphaned files or directories
 * These are files or directories that were unlinked while busy. 
 * If the volume was not cleanly unmounted then some of these may
 * have persisted and need to be removed.
 */
void
hfs_remove_orphans(struct hfsmount * hfsmp)
{
        struct BTreeIterator * iterator = NULL;
        struct FSBufferDescriptor btdata;
        struct HFSPlusCatalogFile filerec;
        struct HFSPlusCatalogKey * keyp;
        struct proc *p = current_proc();
        FCB *fcb;
        ExtendedVCB *vcb;
        char filename[32];
        char tempname[32];
        size_t namelen;
        cat_cookie_t cookie;
        int catlock = 0;
        int catreserve = 0;
        bool started_tr = false;
        int lockflags;
        int result;
        int orphaned_files = 0;
        int orphaned_dirs = 0;

        bzero(&cookie, sizeof(cookie));

        if (hfsmp->hfs_flags & HFS_CLEANED_ORPHANS)
                return;

        vcb = HFSTOVCB(hfsmp);
        fcb = VTOF(hfsmp->hfs_catalog_vp);

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

        iterator = hfs_mallocz(sizeof(*iterator));

        /* Build a key to "temp" */
        keyp = (HFSPlusCatalogKey*)&iterator->key;
        keyp->parentID = hfsmp->hfs_private_desc[FILE_HARDLINKS].cd_cnid;
        keyp->nodeName.length = 4;  /* "temp" */
        keyp->keyLength = kHFSPlusCatalogKeyMinimumLength + keyp->nodeName.length * 2;
        keyp->nodeName.unicode[0] = 't';
        keyp->nodeName.unicode[1] = 'e';
        keyp->nodeName.unicode[2] = 'm';
        keyp->nodeName.unicode[3] = 'p';

        /*
         * Position the iterator just before the first real temp file/dir.
         */
        lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG, HFS_EXCLUSIVE_LOCK);
        (void) BTSearchRecord(fcb, iterator, NULL, NULL, iterator);
        hfs_systemfile_unlock(hfsmp, lockflags);

        /* Visit all the temp files/dirs in the HFS+ private directory. */
        for (;;) {
                lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG, HFS_EXCLUSIVE_LOCK);
                result = BTIterateRecord(fcb, kBTreeNextRecord, iterator, &btdata, NULL);
                hfs_systemfile_unlock(hfsmp, lockflags);
                if (result)
                        break;
                if (keyp->parentID != hfsmp->hfs_private_desc[FILE_HARDLINKS].cd_cnid)
                        break;
                
                (void) utf8_encodestr(keyp->nodeName.unicode, keyp->nodeName.length * 2,
                                      (u_int8_t *)filename, &namelen, sizeof(filename), 0, 0);
                
                (void) snprintf(tempname, sizeof(tempname), "%s%d",
                                HFS_DELETE_PREFIX, filerec.fileID);
                
                /*
                 * Delete all files (and directories) named "tempxxx", 
                 * where xxx is the file's cnid in decimal.
                 *
                 */
                if (bcmp(tempname, filename, namelen + 1) != 0)
                        continue;

                struct filefork dfork;
                struct filefork rfork;
                struct cnode cnode;
                int mode = 0;

                bzero(&dfork, sizeof(dfork));
                bzero(&rfork, sizeof(rfork));
                bzero(&cnode, sizeof(cnode));
                        
                if (hfs_start_transaction(hfsmp) != 0) {
                        printf("hfs_remove_orphans: failed to start transaction\n");
                        goto exit;
                }
                started_tr = true;
                
                /*
                 * Reserve some space in the Catalog file.
                 */
                if (cat_preflight(hfsmp, CAT_DELETE, &cookie, p) != 0) {
                        printf("hfs_remove_orphans: cat_preflight failed\n");
                        goto exit;
                }
                catreserve = 1;

                lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG | SFL_ATTRIBUTE | SFL_EXTENTS | SFL_BITMAP, HFS_EXCLUSIVE_LOCK);
                catlock = 1;

                /* Build a fake cnode */
                cat_convertattr(hfsmp, (CatalogRecord *)&filerec, &cnode.c_attr,
                                                &dfork.ff_data, &rfork.ff_data);
                cnode.c_desc.cd_parentcnid = hfsmp->hfs_private_desc[FILE_HARDLINKS].cd_cnid;
                cnode.c_desc.cd_nameptr = (const u_int8_t *)filename;
                cnode.c_desc.cd_namelen = namelen;
                cnode.c_desc.cd_cnid = cnode.c_attr.ca_fileid;
                cnode.c_blocks = dfork.ff_blocks + rfork.ff_blocks;

                /* Position iterator at previous entry */
                if (BTIterateRecord(fcb, kBTreePrevRecord, iterator,
                                                        NULL, NULL) != 0) {
                        break;
                }

                /* Truncate the file to zero (both forks) */
                if (dfork.ff_blocks > 0) {
                        u_int64_t fsize;
                                
                        dfork.ff_cp = &cnode;
                        cnode.c_datafork = &dfork;
                        cnode.c_rsrcfork = NULL;
                        fsize = (u_int64_t)dfork.ff_blocks * (u_int64_t)HFSTOVCB(hfsmp)->blockSize;
                        while (fsize > 0) {
                                if (fsize > HFS_BIGFILE_SIZE) {
                                        fsize -= HFS_BIGFILE_SIZE;
                                } else {
                                        fsize = 0;
                                }

                                if (TruncateFileC(vcb, (FCB*)&dfork, fsize, 1, 0, 
                                                                  cnode.c_attr.ca_fileid, false) != 0) {
                                        printf("hfs: error truncating data fork!\n");
                                        break;
                                }

                                //
                                // if we're iteratively truncating this file down,
                                // then end the transaction and start a new one so
                                // that no one transaction gets too big.
                                //
                                if (fsize > 0) {
                                        /* Drop system file locks before starting 
                                         * another transaction to preserve lock order.
                                         */
                                        hfs_systemfile_unlock(hfsmp, lockflags);
                                        catlock = 0;
                                        hfs_end_transaction(hfsmp);

                                        if (hfs_start_transaction(hfsmp) != 0) {
                                                started_tr = false;
                                                goto exit;
                                        }
                                        lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG | SFL_ATTRIBUTE | SFL_EXTENTS | SFL_BITMAP, HFS_EXCLUSIVE_LOCK);
                                        catlock = 1;
                                }
                        }
                }

                if (rfork.ff_blocks > 0) {
                        rfork.ff_cp = &cnode;
                        cnode.c_datafork = NULL;
                        cnode.c_rsrcfork = &rfork;
                        if (TruncateFileC(vcb, (FCB*)&rfork, 0, 1, 1, cnode.c_attr.ca_fileid, false) != 0) {
                                printf("hfs: error truncating rsrc fork!\n");
                                break;
                        }
                }

                // Deal with extended attributes
                if (ISSET(cnode.c_attr.ca_recflags, kHFSHasAttributesMask)) {
                        // hfs_removeallattr uses its own transactions
                        hfs_systemfile_unlock(hfsmp, lockflags);
                        catlock = false;
                        hfs_end_transaction(hfsmp);

                        hfs_removeallattr(hfsmp, cnode.c_attr.ca_fileid, &started_tr);

                        if (!started_tr) {
                                if (hfs_start_transaction(hfsmp) != 0) {
                                        printf("hfs_remove_orphans: failed to start transaction\n");
                                        goto exit;
                                }
                                started_tr = true;
                        }

                        lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG | SFL_ATTRIBUTE | SFL_EXTENTS | SFL_BITMAP, HFS_EXCLUSIVE_LOCK);
                        catlock = 1;
                }

                /* Remove the file or folder record from the Catalog */ 
                if (cat_delete(hfsmp, &cnode.c_desc, &cnode.c_attr) != 0) {
                        printf("hfs_remove_orphans: error deleting cat rec for id %d!\n", cnode.c_desc.cd_cnid);
                        hfs_systemfile_unlock(hfsmp, lockflags);
                        catlock = 0;
                        hfs_volupdate(hfsmp, VOL_UPDATE, 0);
                        break;
                }

                mode = cnode.c_attr.ca_mode & S_IFMT;

                if (mode == S_IFDIR) {
                        orphaned_dirs++;
                }
                else {
                        orphaned_files++;
                }

                /* Update parent and volume counts */   
                hfsmp->hfs_private_attr[FILE_HARDLINKS].ca_entries--;
                if (mode == S_IFDIR) {
                        DEC_FOLDERCOUNT(hfsmp, hfsmp->hfs_private_attr[FILE_HARDLINKS]);
                }

                (void)cat_update(hfsmp, &hfsmp->hfs_private_desc[FILE_HARDLINKS],
                                                 &hfsmp->hfs_private_attr[FILE_HARDLINKS], NULL, NULL);

                /* Drop locks and end the transaction */
                hfs_systemfile_unlock(hfsmp, lockflags);
                cat_postflight(hfsmp, &cookie, p);
                catlock = catreserve = 0;

                /* 
                   Now that Catalog is unlocked, update the volume info, making
                   sure to differentiate between files and directories
                */
                if (mode == S_IFDIR) {
                        hfs_volupdate(hfsmp, VOL_RMDIR, 0);
                }
                else{
                        hfs_volupdate(hfsmp, VOL_RMFILE, 0);
                }

                hfs_end_transaction(hfsmp);
                started_tr = false;
        } /* end for */

exit:

        if (orphaned_files > 0 || orphaned_dirs > 0)
                printf("hfs: Removed %d orphaned / unlinked files and %d directories \n", orphaned_files, orphaned_dirs);
        if (catlock) {
                hfs_systemfile_unlock(hfsmp, lockflags);
        }
        if (catreserve) {
                cat_postflight(hfsmp, &cookie, p);
        }
        if (started_tr) {
                hfs_end_transaction(hfsmp);
        }

        hfs_free(iterator, sizeof(*iterator));
        hfsmp->hfs_flags |= HFS_CLEANED_ORPHANS;
}


/*
 * This will return the correct logical block size for a given vnode.
 * For most files, it is the allocation block size, for meta data like
 * BTrees, this is kept as part of the BTree private nodeSize
 */
u_int32_t
GetLogicalBlockSize(struct vnode *vp)
{
u_int32_t logBlockSize;
        
        hfs_assert(vp != NULL);

        /* start with default */
        logBlockSize = VTOHFS(vp)->hfs_logBlockSize;

        if (vnode_issystem(vp)) {
                if (VTOF(vp)->fcbBTCBPtr != NULL) {
                        BTreeInfoRec                    bTreeInfo;
        
                        /*
                         * We do not lock the BTrees, because if we are getting block..then the tree
                         * should be locked in the first place.
                         * We just want the nodeSize wich will NEVER change..so even if the world
                         * is changing..the nodeSize should remain the same. Which argues why lock
                         * it in the first place??
                         */
                        
                        (void) BTGetInformation (VTOF(vp), kBTreeInfoVersion, &bTreeInfo);
                                        
                        logBlockSize = bTreeInfo.nodeSize;

                } else if (VTOC(vp)->c_fileid == kHFSAllocationFileID) {
                                logBlockSize = VTOVCB(vp)->vcbVBMIOSize;
                }
        }

        hfs_assert(logBlockSize > 0);
        
        return logBlockSize;    
}

#if HFS_SPARSE_DEV
static bool hfs_get_backing_free_blks(hfsmount_t *hfsmp, uint64_t *pfree_blks)
{
        struct vfsstatfs *vfsp;  /* 272 bytes */
        uint64_t vfreeblks;
        struct timeval now;

        hfs_lock_mount(hfsmp);

        vnode_t backing_vp = hfsmp->hfs_backingvp;
        if (!backing_vp) {
                hfs_unlock_mount(hfsmp);
                return false;
        }

        // usecount is not enough; we need iocount
        if (vnode_get(backing_vp)) {
                hfs_unlock_mount(hfsmp);
                *pfree_blks = 0;
                return true;
        }

        uint32_t loanedblks = hfsmp->loanedBlocks + hfsmp->lockedBlocks;
        uint32_t bandblks       = hfsmp->hfs_sparsebandblks;
        uint64_t maxblks        = hfsmp->hfs_backingfs_maxblocks;

        hfs_unlock_mount(hfsmp);

        mount_t backingfs_mp = vnode_mount(backing_vp);

        microtime(&now);
        if ((now.tv_sec - hfsmp->hfs_last_backingstatfs) >= 1) {
                vfs_update_vfsstat(backingfs_mp, vfs_context_kernel(), VFS_KERNEL_EVENT);
                hfsmp->hfs_last_backingstatfs = now.tv_sec;
        }

        if (!(vfsp = vfs_statfs(backingfs_mp))) {
                vnode_put(backing_vp);
                return false;
        }

        vfreeblks = vfsp->f_bavail;
        /* Normalize block count if needed. */
        if (vfsp->f_bsize != hfsmp->blockSize)
                vfreeblks = vfreeblks * vfsp->f_bsize / hfsmp->blockSize;
        if (vfreeblks > bandblks)
                vfreeblks -= bandblks;
        else
                vfreeblks = 0;

        /* 
         * Take into account any delayed allocations.  It is not
         * certain what the original reason for the "2 *" is.  Most
         * likely it is to allow for additional requirements in the
         * host file system and metadata required by disk images.  The
         * number of loaned blocks is likely to be small and we will
         * stop using them as we get close to the limit.
         */
        loanedblks = 2 * loanedblks;
        if (vfreeblks > loanedblks)
                vfreeblks -= loanedblks;
        else
                vfreeblks = 0;

        if (maxblks)
                vfreeblks = MIN(vfreeblks, maxblks);

        vnode_put(backing_vp);

        *pfree_blks = vfreeblks;

        return true;
}
#endif

u_int32_t
hfs_free_cnids(struct hfsmount * hfsmp)
{
        return HFS_MAX_FILES - hfsmp->hfs_filecount - hfsmp->hfs_dircount;
}

u_int32_t
hfs_freeblks(struct hfsmount * hfsmp, int wantreserve)
{
        u_int32_t freeblks;
        u_int32_t rsrvblks;
        u_int32_t loanblks;

        /*
         * We don't bother taking the mount lock
         * to look at these values since the values
         * themselves are each updated atomically
         * on aligned addresses.
         */
        freeblks = hfsmp->freeBlocks;
        rsrvblks = hfsmp->reserveBlocks;
        loanblks = hfsmp->loanedBlocks + hfsmp->lockedBlocks;
        if (wantreserve) {
                if (freeblks > rsrvblks)
                        freeblks -= rsrvblks;
                else
                        freeblks = 0;
        }
        if (freeblks > loanblks)
                freeblks -= loanblks;
        else
                freeblks = 0;

#if HFS_SPARSE_DEV
        /* 
         * When the underlying device is sparse, check the
         * available space on the backing store volume.
         */
        uint64_t vfreeblks;
        if (hfs_get_backing_free_blks(hfsmp, &vfreeblks))
                freeblks = MIN(freeblks, vfreeblks);
#endif /* HFS_SPARSE_DEV */

        return (freeblks);
}

/*
 * Map HFS Common errors (negative) to BSD error codes (positive).
 * Positive errors (ie BSD errors) are passed through unchanged.
 */
short MacToVFSError(OSErr err)
{
        if (err >= 0)
                return err;

        /* BSD/VFS internal errnos */
        switch (err) {
                case HFS_ERESERVEDNAME: /* -8 */
                        return err;
        }

        switch (err) {
        case dskFulErr:                 /*    -34 */
        case btNoSpaceAvail:            /* -32733 */
                return ENOSPC;
        case fxOvFlErr:                 /* -32750 */
                return EOVERFLOW;
        
        case btBadNode:                 /* -32731 */
                return EIO;
        
        case memFullErr:                /*  -108 */
                return ENOMEM;          /*   +12 */
        
        case cmExists:                  /* -32718 */
        case btExists:                  /* -32734 */
                return EEXIST;          /*    +17 */
        
        case cmNotFound:                /* -32719 */
        case btNotFound:                /* -32735 */    
                return ENOENT;          /*     28 */
        
        case cmNotEmpty:                /* -32717 */
                return ENOTEMPTY;       /*     66 */
        
        case cmFThdDirErr:              /* -32714 */
                return EISDIR;          /*     21 */
        
        case fxRangeErr:                /* -32751 */
                return ERANGE;
        
        case bdNamErr:                  /*   -37 */
                return ENAMETOOLONG;    /*    63 */
        
        case paramErr:                  /*   -50 */
        case fileBoundsErr:             /* -1309 */
                return EINVAL;          /*   +22 */
        
        case fsBTBadNodeSize:
                return ENXIO;

        default:
                return EIO;             /*   +5 */
        }
}


/*
 * Find the current thread's directory hint for a given index.
 *
 * Requires an exclusive lock on directory cnode.
 *
 * Use detach if the cnode lock must be dropped while the hint is still active.
 */
directoryhint_t *
hfs_getdirhint(struct cnode *dcp, int index, int detach)
{
        struct timeval tv;
        directoryhint_t *hint;
        boolean_t need_remove, need_init;
        const u_int8_t * name;

        microuptime(&tv);

        /*
         *  Look for an existing hint first.  If not found, create a new one (when
         *  the list is not full) or recycle the oldest hint.  Since new hints are
         *  always added to the head of the list, the last hint is always the
         *  oldest.
         */
        TAILQ_FOREACH(hint, &dcp->c_hintlist, dh_link) {
                if (hint->dh_index == index)
                        break;
        }
        if (hint != NULL) { /* found an existing hint */
                need_init = false;
                need_remove = true;
        } else { /* cannot find an existing hint */
                need_init = true;
                if (dcp->c_dirhintcnt < HFS_MAXDIRHINTS) { /* we don't need recycling */
                        /* Create a default directory hint */
                        hint = hfs_malloc(sizeof(directoryhint_t));
                        ++dcp->c_dirhintcnt;
                        need_remove = false;
                } else {                                /* recycle the last (i.e., the oldest) hint */
                        hint = TAILQ_LAST(&dcp->c_hintlist, hfs_hinthead);
                        if ((hint->dh_desc.cd_flags & CD_HASBUF) &&
                            (name = hint->dh_desc.cd_nameptr)) {
                                hint->dh_desc.cd_nameptr = NULL;
                                hint->dh_desc.cd_namelen = 0;
                                hint->dh_desc.cd_flags &= ~CD_HASBUF;                           
                                vfs_removename((const char *)name);
                        }
                        need_remove = true;
                }
        }

        if (need_remove)
                TAILQ_REMOVE(&dcp->c_hintlist, hint, dh_link);

        if (detach)
                --dcp->c_dirhintcnt;
        else
                TAILQ_INSERT_HEAD(&dcp->c_hintlist, hint, dh_link);

        if (need_init) {
                hint->dh_index = index;
                hint->dh_desc.cd_flags = 0;
                hint->dh_desc.cd_encoding = 0;
                hint->dh_desc.cd_namelen = 0;
                hint->dh_desc.cd_nameptr = NULL;
                hint->dh_desc.cd_parentcnid = dcp->c_fileid;
                hint->dh_desc.cd_hint = dcp->c_childhint;
                hint->dh_desc.cd_cnid = 0;
        }
        hint->dh_time = tv.tv_sec;
        return (hint);
}

/*
 * Release a single directory hint.
 *
 * Requires an exclusive lock on directory cnode.
 */
void
hfs_reldirhint(struct cnode *dcp, directoryhint_t * relhint)
{
        const u_int8_t * name;
        directoryhint_t *hint;

        /* Check if item is on list (could be detached) */
        TAILQ_FOREACH(hint, &dcp->c_hintlist, dh_link) {
                if (hint == relhint) {
                        TAILQ_REMOVE(&dcp->c_hintlist, relhint, dh_link);
                        --dcp->c_dirhintcnt;
                        break;
                }
        }
        name = relhint->dh_desc.cd_nameptr;
        if ((relhint->dh_desc.cd_flags & CD_HASBUF) && (name != NULL)) {
                relhint->dh_desc.cd_nameptr = NULL;
                relhint->dh_desc.cd_namelen = 0;
                relhint->dh_desc.cd_flags &= ~CD_HASBUF;
                vfs_removename((const char *)name);
        }
        hfs_free(relhint, sizeof(*relhint));
}

/*
 * Release directory hints for given directory
 *
 * Requires an exclusive lock on directory cnode.
 */
void
hfs_reldirhints(struct cnode *dcp, int stale_hints_only)
{
        struct timeval tv;
        directoryhint_t *hint, *prev;
        const u_int8_t * name;

        if (stale_hints_only)
                microuptime(&tv);

        /* searching from the oldest to the newest, so we can stop early when releasing stale hints only */
        for (hint = TAILQ_LAST(&dcp->c_hintlist, hfs_hinthead); hint != NULL; hint = prev) {
                if (stale_hints_only && (tv.tv_sec - hint->dh_time) < HFS_DIRHINT_TTL)
                        break;  /* stop here if this entry is too new */
                name = hint->dh_desc.cd_nameptr;
                if ((hint->dh_desc.cd_flags & CD_HASBUF) && (name != NULL)) {
                        hint->dh_desc.cd_nameptr = NULL;
                        hint->dh_desc.cd_namelen = 0;
                        hint->dh_desc.cd_flags &= ~CD_HASBUF;
                        vfs_removename((const char *)name);
                }
                prev = TAILQ_PREV(hint, hfs_hinthead, dh_link); /* must save this pointer before calling FREE_ZONE on this node */
                TAILQ_REMOVE(&dcp->c_hintlist, hint, dh_link);
                hfs_free(hint, sizeof(*hint));
                --dcp->c_dirhintcnt;
        }
}

/*
 * Insert a detached directory hint back into the list of dirhints.
 *
 * Requires an exclusive lock on directory cnode.
 */
void
hfs_insertdirhint(struct cnode *dcp, directoryhint_t * hint)
{
        directoryhint_t *test;

        TAILQ_FOREACH(test, &dcp->c_hintlist, dh_link) {
                if (test == hint)
                        panic("hfs_insertdirhint: hint %p already on list!", hint);
        }

        TAILQ_INSERT_HEAD(&dcp->c_hintlist, hint, dh_link);
        ++dcp->c_dirhintcnt;
}

/*
 * Perform a case-insensitive compare of two UTF-8 filenames.
 *
 * Returns 0 if the strings match.
 */
int
hfs_namecmp(const u_int8_t *str1, size_t len1, const u_int8_t *str2, size_t len2)
{
        u_int16_t *ustr1, *ustr2;
        size_t ulen1, ulen2;
        size_t maxbytes;
        int cmp = -1;

        if (len1 != len2)
                return (cmp);

        maxbytes = kHFSPlusMaxFileNameChars << 1;
        ustr1 = hfs_malloc(maxbytes << 1);
        ustr2 = ustr1 + (maxbytes >> 1);

        if (utf8_decodestr(str1, len1, ustr1, &ulen1, maxbytes, ':', 0) != 0)
                goto out;
        if (utf8_decodestr(str2, len2, ustr2, &ulen2, maxbytes, ':', 0) != 0)
                goto out;
        
        cmp = FastUnicodeCompare(ustr1, ulen1>>1, ustr2, ulen2>>1);
out:
        hfs_free(ustr1, maxbytes << 1);
        return (cmp);
}

typedef struct jopen_cb_info {
        mount_t mp;
        off_t   jsize;
        char   *desired_uuid;
        struct  vnode *jvp;
        size_t  blksize;
        int     need_clean;
        int     need_init;
} jopen_cb_info;

static int
journal_open_cb(const char *bsd_dev_name, const char *uuid_str, void *arg)
{
        jopen_cb_info *ji = (jopen_cb_info *)arg;
        char bsd_name[256];
        int error;

        strlcpy(&bsd_name[0], "/dev/", sizeof(bsd_name));
        strlcpy(&bsd_name[5], bsd_dev_name, sizeof(bsd_name)-5);

        if ((error = vnode_lookup(bsd_name, VNODE_LOOKUP_NOFOLLOW, &ji->jvp,
                                                          vfs_context_kernel()))) {
                printf("hfs: journal open cb: error %d looking up device %s (dev uuid %s)\n", error, bsd_name, uuid_str);
                return 1;   // keep iterating
        }

        struct vnop_open_args oargs = {
                .a_vp           = ji->jvp,
                .a_mode         = FREAD | FWRITE,
                .a_context      = vfs_context_kernel(),
        };

        if (spec_open(&oargs)) {
                vnode_put(ji->jvp);
                ji->jvp = NULL;
                return 1;
        }

        // if the journal is dirty and we didn't specify a desired
        // journal device uuid, then do not use the journal.  but
        // if the journal is just invalid (e.g. it hasn't been
        // initialized) then just set the need_init flag.
        if (ji->need_clean && ji->desired_uuid && ji->desired_uuid[0] == '\0') {
                error = journal_is_clean(ji->jvp, 0, ji->jsize,
                                                                 (void *)1, ji->blksize);
                if (error == EBUSY) {
                        struct vnop_close_args cargs = {
                                .a_vp           = ji->jvp,
                                .a_fflag        = FREAD | FWRITE,
                                .a_context      = vfs_context_kernel()
                        };
                        spec_close(&cargs);
                        vnode_put(ji->jvp);
                        ji->jvp = NULL;
                        return 1;    // keep iterating
                } else if (error == EINVAL) {
                        ji->need_init = 1;
                }
        }

        if (ji->desired_uuid && ji->desired_uuid[0] == '\0') {
                strlcpy(ji->desired_uuid, uuid_str, 128);
        }
        vnode_setmountedon(ji->jvp);
        return 0;   // stop iterating
}

static vnode_t
open_journal_dev(mount_t mp,
                                 const char *vol_device,
                                 int need_clean,
                                 char *uuid_str,
                                 char *machine_serial_num,
                                 off_t jsize,
                                 size_t blksize,
                                 int *need_init)
{
    int retry_counter=0;
    jopen_cb_info ji;

        ji.mp                   = mp;
    ji.jsize        = jsize;
    ji.desired_uuid = uuid_str;
    ji.jvp          = NULL;
    ji.blksize      = blksize;
    ji.need_clean   = need_clean;
    ji.need_init    = 0;

//    if (uuid_str[0] == '\0') {
//          printf("hfs: open journal dev: %s: locating any available non-dirty external journal partition\n", vol_device);
//    } else {
//          printf("hfs: open journal dev: %s: trying to find the external journal partition w/uuid %s\n", vol_device, uuid_str);
//    }
    while (ji.jvp == NULL && retry_counter++ < 4) {
            if (retry_counter > 1) {
                    if (uuid_str[0]) {
                            printf("hfs: open_journal_dev: uuid %s not found.  waiting 10sec.\n", uuid_str);
                    } else {
                            printf("hfs: open_journal_dev: no available external journal partition found.  waiting 10sec.\n");
                    }
                    delay_for_interval(10* 1000000, NSEC_PER_USEC);    // wait for ten seconds and then try again
            }

            hfs_iterate_media_with_content(EXTJNL_CONTENT_TYPE_UUID,
                                                                           journal_open_cb, &ji);
    }

    if (ji.jvp == NULL) {
            printf("hfs: volume: %s: did not find jnl device uuid: %s from machine serial number: %s\n",
                   vol_device, uuid_str, machine_serial_num);
    }

    *need_init = ji.need_init;

    return ji.jvp;
}

void hfs_close_jvp(hfsmount_t *hfsmp)
{
        if (!hfsmp || !hfsmp->jvp || hfsmp->jvp == hfsmp->hfs_devvp)
                return;

        vnode_clearmountedon(hfsmp->jvp);
        struct vnop_close_args cargs = {
                .a_vp           = hfsmp->jvp,
                .a_fflag        = FREAD | FWRITE,
                .a_context      = vfs_context_kernel()
        };
        spec_close(&cargs);
        vnode_put(hfsmp->jvp);
        hfsmp->jvp = NULL;
}

int
hfs_early_journal_init(struct hfsmount *hfsmp, HFSPlusVolumeHeader *vhp,
                                           void *_args, off_t embeddedOffset, daddr64_t mdb_offset,
                                           HFSMasterDirectoryBlock *mdbp, kauth_cred_t cred)
{
        JournalInfoBlock *jibp;
        struct buf       *jinfo_bp, *bp;
        int               sectors_per_fsblock, arg_flags=0, arg_tbufsz=0;
        int               retval, write_jibp = 0;
        uint32_t                  blksize = hfsmp->hfs_logical_block_size;
        struct vnode     *devvp;
        struct hfs_mount_args *args = _args;
        u_int32_t         jib_flags;
        u_int64_t         jib_offset;
        u_int64_t         jib_size;
        const char *dev_name;
        
        devvp = hfsmp->hfs_devvp;
        dev_name = vnode_getname_printable(devvp);

        if (args != NULL && (args->flags & HFSFSMNT_EXTENDED_ARGS)) {
                arg_flags  = args->journal_flags;
                arg_tbufsz = args->journal_tbuffer_size;
        }

        sectors_per_fsblock = SWAP_BE32(vhp->blockSize) / blksize;
                                
        jinfo_bp = NULL;
        retval = (int)buf_meta_bread(devvp,
                                                (daddr64_t)((embeddedOffset/blksize) + 
                                                ((u_int64_t)SWAP_BE32(vhp->journalInfoBlock)*sectors_per_fsblock)),
                                                hfsmp->hfs_physical_block_size, cred, &jinfo_bp);
        if (retval) {
                if (jinfo_bp) {
                        buf_brelse(jinfo_bp);
                }
                goto cleanup_dev_name;
        }
        
        jibp = (JournalInfoBlock *)buf_dataptr(jinfo_bp);
        jib_flags  = SWAP_BE32(jibp->flags);
        jib_size   = SWAP_BE64(jibp->size);

        if (jib_flags & kJIJournalInFSMask) {
                hfsmp->jvp = hfsmp->hfs_devvp;
                jib_offset = SWAP_BE64(jibp->offset);
        } else {
            int need_init=0;
        
            // if the volume was unmounted cleanly then we'll pick any
            // available external journal partition
            //
            if (SWAP_BE32(vhp->attributes) & kHFSVolumeUnmountedMask) {
                    *((char *)&jibp->ext_jnl_uuid[0]) = '\0';
            }

            hfsmp->jvp = open_journal_dev(hfsmp->hfs_mp,
                                                                          dev_name,
                                                                          !(jib_flags & kJIJournalNeedInitMask),
                                                                          (char *)&jibp->ext_jnl_uuid[0],
                                                                          (char *)&jibp->machine_serial_num[0],
                                                                          jib_size,
                                                                          hfsmp->hfs_logical_block_size,
                                                                          &need_init);
            if (hfsmp->jvp == NULL) {
                    buf_brelse(jinfo_bp);
                    retval = EROFS;
                    goto cleanup_dev_name;
            } else {
                    if (hfs_get_platform_serial_number(&jibp->machine_serial_num[0], sizeof(jibp->machine_serial_num)) != KERN_SUCCESS) {
                            strlcpy(&jibp->machine_serial_num[0], "unknown-machine-uuid", sizeof(jibp->machine_serial_num));
                    }
            }

            jib_offset = 0;
            write_jibp = 1;
            if (need_init) {
                    jib_flags |= kJIJournalNeedInitMask;
            }
        }

        // save this off for the hack-y check in hfs_remove()
        hfsmp->jnl_start = jib_offset / SWAP_BE32(vhp->blockSize);
        hfsmp->jnl_size  = jib_size;

        if ((hfsmp->hfs_flags & HFS_READ_ONLY) && (vfs_flags(hfsmp->hfs_mp) & MNT_ROOTFS) == 0) {
            // if the file system is read-only, check if the journal is empty.
            // if it is, then we can allow the mount.  otherwise we have to
            // return failure.
            retval = journal_is_clean(hfsmp->jvp,
                                      jib_offset + embeddedOffset,
                                      jib_size,
                                      devvp,
                                      hfsmp->hfs_logical_block_size);

            hfsmp->jnl = NULL;

            buf_brelse(jinfo_bp);

            if (retval) {
                    const char *name = vnode_getname_printable(devvp);
                    printf("hfs: early journal init: volume on %s is read-only and journal is dirty.  Can not mount volume.\n",
                    name);
                    vnode_putname_printable(name);
            }

            goto cleanup_dev_name;
        }

        if (jib_flags & kJIJournalNeedInitMask) {
                printf("hfs: Initializing the journal (joffset 0x%llx sz 0x%llx)...\n",
                           jib_offset + embeddedOffset, jib_size);
                hfsmp->jnl = journal_create(hfsmp->jvp,
                                                                        jib_offset + embeddedOffset,
                                                                        jib_size,
                                                                        devvp,
                                                                        blksize,
                                                                        arg_flags,
                                                                        arg_tbufsz,
                                                                        hfs_sync_metadata, hfsmp->hfs_mp,
                                                                        hfsmp->hfs_mp);
                if (hfsmp->jnl)
                        journal_trim_set_callback(hfsmp->jnl, hfs_trim_callback, hfsmp);

                // no need to start a transaction here... if this were to fail
                // we'd just re-init it on the next mount.
                jib_flags &= ~kJIJournalNeedInitMask;
                jibp->flags  = SWAP_BE32(jib_flags);
                buf_bwrite(jinfo_bp);
                jinfo_bp = NULL;
                jibp     = NULL;
        } else { 
                //printf("hfs: Opening the journal (joffset 0x%llx sz 0x%llx vhp_blksize %d)...\n",
                //         jib_offset + embeddedOffset,
                //         jib_size, SWAP_BE32(vhp->blockSize));
                                
                hfsmp->jnl = journal_open(hfsmp->jvp,
                                                                  jib_offset + embeddedOffset,
                                                                  jib_size,
                                                                  devvp,
                                                                  blksize,
                                                                  arg_flags,
                                                                  arg_tbufsz,
                                                                  hfs_sync_metadata, hfsmp->hfs_mp,
                                                                  hfsmp->hfs_mp);
                if (hfsmp->jnl)
                        journal_trim_set_callback(hfsmp->jnl, hfs_trim_callback, hfsmp);

                if (write_jibp) {
                        buf_bwrite(jinfo_bp);
                } else {
                        buf_brelse(jinfo_bp);
                }
                jinfo_bp = NULL;
                jibp     = NULL;

                if (hfsmp->jnl && mdbp) {
                        // reload the mdb because it could have changed
                        // if the journal had to be replayed.
                        if (mdb_offset == 0) {
                                mdb_offset = (daddr64_t)((embeddedOffset / blksize) + HFS_PRI_SECTOR(blksize));
                        }
                        bp = NULL;
                        retval = (int)buf_meta_bread(devvp, 
                                        HFS_PHYSBLK_ROUNDDOWN(mdb_offset, hfsmp->hfs_log_per_phys),
                                        hfsmp->hfs_physical_block_size, cred, &bp);
                        if (retval) {
                                if (bp) {
                                        buf_brelse(bp);
                                }
                                printf("hfs: failed to reload the mdb after opening the journal (retval %d)!\n",
                                           retval);
                                goto cleanup_dev_name;
                        }
                        bcopy((char *)buf_dataptr(bp) + HFS_PRI_OFFSET(hfsmp->hfs_physical_block_size), mdbp, 512);
                        buf_brelse(bp);
                        bp = NULL;
                }
        }

        // if we expected the journal to be there and we couldn't
        // create it or open it then we have to bail out.
        if (hfsmp->jnl == NULL) {
                printf("hfs: early jnl init: failed to open/create the journal (retval %d).\n", retval);
                retval = EINVAL;
                goto cleanup_dev_name;
        }

        retval = 0;
        
cleanup_dev_name:
        vnode_putname_printable(dev_name);
        return retval;
}


//
// This function will go and re-locate the .journal_info_block and
// the .journal files in case they moved (which can happen if you
// run Norton SpeedDisk).  If we fail to find either file we just
// disable journaling for this volume and return.  We turn off the
// journaling bit in the vcb and assume it will get written to disk
// later (if it doesn't on the next mount we'd do the same thing
// again which is harmless).  If we disable journaling we don't
// return an error so that the volume is still mountable.
//
// If the info we find for the .journal_info_block and .journal files
// isn't what we had stored, we re-set our cached info and proceed
// with opening the journal normally.
//
static int
hfs_late_journal_init(struct hfsmount *hfsmp, HFSPlusVolumeHeader *vhp, void *_args)
{
        JournalInfoBlock *jibp;
        struct buf       *jinfo_bp;
        int               sectors_per_fsblock, arg_flags=0, arg_tbufsz=0;
        int               retval, write_jibp = 0, recreate_journal = 0;
        struct vnode     *devvp;
        struct cat_attr   jib_attr, jattr;
        struct cat_fork   jib_fork, jfork;
        ExtendedVCB      *vcb;
        u_int32_t            fid;
        struct hfs_mount_args *args = _args;
        u_int32_t         jib_flags;
        u_int64_t         jib_offset;
        u_int64_t         jib_size;
        
        devvp = hfsmp->hfs_devvp;
        vcb = HFSTOVCB(hfsmp);
        
        if (args != NULL && (args->flags & HFSFSMNT_EXTENDED_ARGS)) {
                if (args->journal_disable) {
                        return 0;
                }

                arg_flags  = args->journal_flags;
                arg_tbufsz = args->journal_tbuffer_size;
        }

        fid = GetFileInfo(vcb, kRootDirID, ".journal_info_block", &jib_attr, &jib_fork);
        if (fid == 0 || jib_fork.cf_extents[0].startBlock == 0 || jib_fork.cf_size == 0) {
                printf("hfs: can't find the .journal_info_block! disabling journaling (start: %d).\n",
                           fid ? jib_fork.cf_extents[0].startBlock : 0);
                vcb->vcbAtrb &= ~kHFSVolumeJournaledMask;
                return 0;
        }
        hfsmp->hfs_jnlinfoblkid = fid;

        // make sure the journal_info_block begins where we think it should.
        if (SWAP_BE32(vhp->journalInfoBlock) != jib_fork.cf_extents[0].startBlock) {
                printf("hfs: The journal_info_block moved (was: %d; is: %d).  Fixing up\n",
                           SWAP_BE32(vhp->journalInfoBlock), jib_fork.cf_extents[0].startBlock);

                vcb->vcbJinfoBlock    = jib_fork.cf_extents[0].startBlock;
                vhp->journalInfoBlock = SWAP_BE32(jib_fork.cf_extents[0].startBlock);
                recreate_journal = 1;
        }


        sectors_per_fsblock = SWAP_BE32(vhp->blockSize) / hfsmp->hfs_logical_block_size;
        jinfo_bp = NULL;
        retval = (int)buf_meta_bread(devvp,
                                                (vcb->hfsPlusIOPosOffset / hfsmp->hfs_logical_block_size + 
                                                ((u_int64_t)SWAP_BE32(vhp->journalInfoBlock)*sectors_per_fsblock)),
                                                hfsmp->hfs_physical_block_size, NOCRED, &jinfo_bp);
        if (retval) {
                if (jinfo_bp) {
                        buf_brelse(jinfo_bp);
                }
                printf("hfs: can't read journal info block. disabling journaling.\n");
                vcb->vcbAtrb &= ~kHFSVolumeJournaledMask;
                return 0;
        }

        jibp = (JournalInfoBlock *)buf_dataptr(jinfo_bp);
        jib_flags  = SWAP_BE32(jibp->flags);
        jib_offset = SWAP_BE64(jibp->offset);
        jib_size   = SWAP_BE64(jibp->size);

        fid = GetFileInfo(vcb, kRootDirID, ".journal", &jattr, &jfork);
        if (fid == 0 || jfork.cf_extents[0].startBlock == 0 || jfork.cf_size == 0) {
                printf("hfs: can't find the journal file! disabling journaling (start: %d)\n",
                           fid ? jfork.cf_extents[0].startBlock : 0);
                buf_brelse(jinfo_bp);
                vcb->vcbAtrb &= ~kHFSVolumeJournaledMask;
                return 0;
        }
        hfsmp->hfs_jnlfileid = fid;

        // make sure the journal file begins where we think it should.
        if ((jib_flags & kJIJournalInFSMask) && (jib_offset / (u_int64_t)vcb->blockSize) != jfork.cf_extents[0].startBlock) {
                printf("hfs: The journal file moved (was: %lld; is: %d).  Fixing up\n",
                           (jib_offset / (u_int64_t)vcb->blockSize), jfork.cf_extents[0].startBlock);

                jib_offset = (u_int64_t)jfork.cf_extents[0].startBlock * (u_int64_t)vcb->blockSize;
                write_jibp   = 1;
                recreate_journal = 1;
        }

        // check the size of the journal file.
        if (jib_size != (u_int64_t)jfork.cf_extents[0].blockCount*vcb->blockSize) {
                printf("hfs: The journal file changed size! (was %lld; is %lld).  Fixing up.\n",
                           jib_size, (u_int64_t)jfork.cf_extents[0].blockCount*vcb->blockSize);
                
                jib_size = (u_int64_t)jfork.cf_extents[0].blockCount * vcb->blockSize;
                write_jibp = 1;
                recreate_journal = 1;
        }
        
        if (jib_flags & kJIJournalInFSMask) {
                hfsmp->jvp = hfsmp->hfs_devvp;
                jib_offset += (off_t)vcb->hfsPlusIOPosOffset;
        } else {
            const char *dev_name;
            int need_init = 0;
        
            dev_name = vnode_getname_printable(devvp);

            // since the journal is empty, just use any available external journal
            *((char *)&jibp->ext_jnl_uuid[0]) = '\0';

            // this fills in the uuid of the device we actually get
            hfsmp->jvp = open_journal_dev(hfsmp->hfs_mp,
                                                                          dev_name,
                                                                          !(jib_flags & kJIJournalNeedInitMask),
                                                                          (char *)&jibp->ext_jnl_uuid[0],
                                                                          (char *)&jibp->machine_serial_num[0],
                                                                          jib_size,
                                                                          hfsmp->hfs_logical_block_size,
                                                                          &need_init);
            if (hfsmp->jvp == NULL) {
                    buf_brelse(jinfo_bp);
                    vnode_putname_printable(dev_name);
                    return EROFS;
            } else {
                    if (hfs_get_platform_serial_number(&jibp->machine_serial_num[0], sizeof(jibp->machine_serial_num)) != KERN_SUCCESS) {
                            strlcpy(&jibp->machine_serial_num[0], "unknown-machine-serial-num", sizeof(jibp->machine_serial_num));
                    }
            }
            jib_offset = 0;
            recreate_journal = 1;
            write_jibp = 1;
            if (need_init) {
                    jib_flags |= kJIJournalNeedInitMask;
            }
            vnode_putname_printable(dev_name);
        }

        // save this off for the hack-y check in hfs_remove()
        hfsmp->jnl_start = jib_offset / SWAP_BE32(vhp->blockSize);
        hfsmp->jnl_size  = jib_size;

        if ((hfsmp->hfs_flags & HFS_READ_ONLY) && (vfs_flags(hfsmp->hfs_mp) & MNT_ROOTFS) == 0) {
            // if the file system is read-only, check if the journal is empty.
            // if it is, then we can allow the mount.  otherwise we have to
            // return failure.
            retval = journal_is_clean(hfsmp->jvp,
                                      jib_offset,
                                      jib_size,
                                      devvp,
                                      hfsmp->hfs_logical_block_size);

            hfsmp->jnl = NULL;

            buf_brelse(jinfo_bp);

            if (retval) {
                    const char *name = vnode_getname_printable(devvp);
                    printf("hfs: late journal init: volume on %s is read-only and journal is dirty.  Can not mount volume.\n", 
                    name);
                    vnode_putname_printable(name);
            }

            return retval;
        }

        if ((jib_flags & kJIJournalNeedInitMask) || recreate_journal) {
                printf("hfs: Initializing the journal (joffset 0x%llx sz 0x%llx)...\n",
                           jib_offset, jib_size);
                hfsmp->jnl = journal_create(hfsmp->jvp,
                                                                        jib_offset,
                                                                        jib_size,
                                                                        devvp,
                                                                        hfsmp->hfs_logical_block_size,
                                                                        arg_flags,
                                                                        arg_tbufsz,
                                                                        hfs_sync_metadata, hfsmp->hfs_mp,
                                                                        hfsmp->hfs_mp);
                if (hfsmp->jnl)
                        journal_trim_set_callback(hfsmp->jnl, hfs_trim_callback, hfsmp);

                // no need to start a transaction here... if this were to fail
                // we'd just re-init it on the next mount.
                jib_flags &= ~kJIJournalNeedInitMask;
                write_jibp   = 1;

        } else { 
                //
                // if we weren't the last person to mount this volume
                // then we need to throw away the journal because it
                // is likely that someone else mucked with the disk.
                // if the journal is empty this is no big deal.  if the
                // disk is dirty this prevents us from replaying the
                // journal over top of changes that someone else made.
                //
                arg_flags |= JOURNAL_RESET;
                
                //printf("hfs: Opening the journal (joffset 0x%llx sz 0x%llx vhp_blksize %d)...\n",
                //         jib_offset,
                //         jib_size, SWAP_BE32(vhp->blockSize));
                                
                hfsmp->jnl = journal_open(hfsmp->jvp,
                                                                  jib_offset,
                                                                  jib_size,
                                                                  devvp,
                                                                  hfsmp->hfs_logical_block_size,
                                                                  arg_flags,
                                                                  arg_tbufsz,
                                                                  hfs_sync_metadata, hfsmp->hfs_mp,
                                                                  hfsmp->hfs_mp);
                if (hfsmp->jnl)
                        journal_trim_set_callback(hfsmp->jnl, hfs_trim_callback, hfsmp);
        }
                        

        if (write_jibp) {
                jibp->flags  = SWAP_BE32(jib_flags);
                jibp->offset = SWAP_BE64(jib_offset);
                jibp->size   = SWAP_BE64(jib_size);

                buf_bwrite(jinfo_bp);
        } else {
                buf_brelse(jinfo_bp);
        } 
        jinfo_bp = NULL;
        jibp     = NULL;

        // if we expected the journal to be there and we couldn't
        // create it or open it then we have to bail out.
        if (hfsmp->jnl == NULL) {
                printf("hfs: late jnl init: failed to open/create the journal (retval %d).\n", retval);
                return EINVAL;
        }

        return 0;
}

/*
 * Calculate the allocation zone for metadata.
 *
 * This zone includes the following:
 *      Allocation Bitmap file
 *      Overflow Extents file
 *      Journal file
 *      Quota files
 *      Clustered Hot files
 *      Catalog file
 *
 *                          METADATA ALLOCATION ZONE
 * ____________________________________________________________________________
 * |    |    |     |               |                              |           |
 * | BM | JF | OEF |    CATALOG    |--->                          | HOT FILES |
 * |____|____|_____|_______________|______________________________|___________|
 *
 * <------------------------------- N * 128 MB ------------------------------->
 *
 */
#define GIGABYTE  (u_int64_t)(1024*1024*1024)

#define HOTBAND_MINIMUM_SIZE  (10*1024*1024)
#define HOTBAND_MAXIMUM_SIZE  (512*1024*1024)

/* Initialize the metadata zone.
 *
 * If the size of  the volume is less than the minimum size for
 * metadata zone, metadata zone is disabled.
 *
 * If disable is true, disable metadata zone unconditionally.
 */
void
hfs_metadatazone_init(struct hfsmount *hfsmp, int disable)
{
        ExtendedVCB  *vcb;
        u_int64_t  fs_size;
        u_int64_t  zonesize;
        u_int64_t  temp;
        u_int64_t  filesize;
        u_int32_t  blk;
        int  items, really_do_it=1;

        vcb = HFSTOVCB(hfsmp);
        fs_size = (u_int64_t)vcb->blockSize * (u_int64_t)vcb->allocLimit;

        /*
         * For volumes less than 10 GB, don't bother.
         */
        if (fs_size < ((u_int64_t)10 * GIGABYTE)) {
                really_do_it = 0;
        }
        
        /*
         * Skip non-journaled volumes as well.
         */
        if (hfsmp->jnl == NULL) {
                really_do_it = 0;
        }

        /* If caller wants to disable metadata zone, do it */
        if (disable == true) {
                really_do_it = 0;
        }

        /*
         * Start with space for the boot blocks and Volume Header.
         * 1536 = byte offset from start of volume to end of volume header:
         * 1024 bytes is the offset from the start of the volume to the
         * start of the volume header (defined by the volume format)
         * + 512 bytes (the size of the volume header).
         */
        zonesize = roundup(1536, hfsmp->blockSize);
        
        /*
         * Add the on-disk size of allocation bitmap.
         */
        zonesize += hfsmp->hfs_allocation_cp->c_datafork->ff_blocks * hfsmp->blockSize;
        
        /* 
         * Add space for the Journal Info Block and Journal (if they're in
         * this file system).
         */
        if (hfsmp->jnl && hfsmp->jvp == hfsmp->hfs_devvp) {
                zonesize += hfsmp->blockSize + hfsmp->jnl_size;
        }
        
        /*
         * Add the existing size of the Extents Overflow B-tree.
         * (It rarely grows, so don't bother reserving additional room for it.)
         */
        zonesize += hfs_blk_to_bytes(hfsmp->hfs_extents_cp->c_datafork->ff_blocks, hfsmp->blockSize);
        
        /*
         * If there is an Attributes B-tree, leave room for 11 clumps worth.
         * newfs_hfs allocates one clump, and leaves a gap of 10 clumps.
         * When installing a full OS install onto a 20GB volume, we use
         * 7 to 8 clumps worth of space (depending on packages), so that leaves
         * us with another 3 or 4 clumps worth before we need another extent.
         */
        if (hfsmp->hfs_attribute_cp) {
                zonesize += 11 * hfsmp->hfs_attribute_cp->c_datafork->ff_clumpsize;
        }
        
        /*
         * Leave room for 11 clumps of the Catalog B-tree.
         * Again, newfs_hfs allocates one clump plus a gap of 10 clumps.
         * When installing a full OS install onto a 20GB volume, we use
         * 7 to 8 clumps worth of space (depending on packages), so that leaves
         * us with another 3 or 4 clumps worth before we need another extent.
         */
        zonesize += 11 * hfsmp->hfs_catalog_cp->c_datafork->ff_clumpsize;
        
        /*
         * Add space for hot file region.
         *
         * ...for now, use 5 MB per 1 GB (0.5 %)
         */
        filesize = (fs_size / 1024) * 5;
        if (filesize > HOTBAND_MAXIMUM_SIZE)
                filesize = HOTBAND_MAXIMUM_SIZE;
        else if (filesize < HOTBAND_MINIMUM_SIZE)
                filesize = HOTBAND_MINIMUM_SIZE;
        /*
         * Calculate user quota file requirements.
         */
        if (hfsmp->hfs_flags & HFS_QUOTAS) {
                items = QF_USERS_PER_GB * (fs_size / GIGABYTE);
                if (items < QF_MIN_USERS)
                        items = QF_MIN_USERS;
                else if (items > QF_MAX_USERS)
                        items = QF_MAX_USERS;
                if (!powerof2(items)) {
                        int x = items;
                        items = 4;
                        while (x>>1 != 1) {
                                x = x >> 1;
                                items = items << 1;
                        }
                }
                filesize += (items + 1) * sizeof(struct dqblk);
                /*
                 * Calculate group quota file requirements.
                 *
                 */
                items = QF_GROUPS_PER_GB * (fs_size / GIGABYTE);
                if (items < QF_MIN_GROUPS)
                        items = QF_MIN_GROUPS;
                else if (items > QF_MAX_GROUPS)
                        items = QF_MAX_GROUPS;
                if (!powerof2(items)) {
                        int x = items;
                        items = 4;
                        while (x>>1 != 1) {
                                x = x >> 1;
                                items = items << 1;
                        }
                }
                filesize += (items + 1) * sizeof(struct dqblk);
        }
        zonesize += filesize;

        /*
         * Round up entire zone to a bitmap block's worth.
         * The extra space goes to the catalog file and hot file area.
         */
        temp = zonesize;
        zonesize = roundup(zonesize, (u_int64_t)vcb->vcbVBMIOSize * 8 * vcb->blockSize);
        hfsmp->hfs_min_alloc_start = zonesize / vcb->blockSize;
        /*
         * If doing the round up for hfs_min_alloc_start would push us past
         * allocLimit, then just reset it back to 0.  Though using a value 
         * bigger than allocLimit would not cause damage in the block allocator
         * code, this value could get stored in the volume header and make it out 
         * to disk, making the volume header technically corrupt.
         */
        if (hfsmp->hfs_min_alloc_start >= hfsmp->allocLimit) {
                hfsmp->hfs_min_alloc_start = 0;
        }

        if (really_do_it == 0) {
                /* If metadata zone needs to be disabled because the 
                 * volume was truncated, clear the bit and zero out 
                 * the values that are no longer needed.
                 */
                if (hfsmp->hfs_flags & HFS_METADATA_ZONE) {
                        /* Disable metadata zone */
                        hfsmp->hfs_flags &= ~HFS_METADATA_ZONE;
                        
                        /* Zero out mount point values that are not required */
                        hfsmp->hfs_catalog_maxblks = 0;
                        hfsmp->hfs_hotfile_maxblks = 0;
                        hfsmp->hfs_hotfile_start = 0;
                        hfsmp->hfs_hotfile_end = 0;
                        hfsmp->hfs_hotfile_freeblks = 0;
                        hfsmp->hfs_metazone_start = 0;
                        hfsmp->hfs_metazone_end = 0;
                }
                
                return;
        }
        
        temp = zonesize - temp;  /* temp has extra space */
        filesize += temp / 3;
        hfsmp->hfs_catalog_maxblks += (temp - (temp / 3)) / vcb->blockSize;

        if (hfsmp->hfs_flags & HFS_CS_HOTFILE_PIN) {
                hfsmp->hfs_hotfile_maxblks = (uint32_t) (hfsmp->hfs_cs_hotfile_size / HFSTOVCB(hfsmp)->blockSize);
        } else {
                hfsmp->hfs_hotfile_maxblks = filesize / vcb->blockSize;
        }

        /* Convert to allocation blocks. */
        blk = zonesize / vcb->blockSize;

        /* The default metadata zone location is at the start of volume. */
        hfsmp->hfs_metazone_start = 1;
        hfsmp->hfs_metazone_end = blk - 1;
        
        /* The default hotfile area is at the end of the zone. */
        if (vfs_flags(HFSTOVFS(hfsmp)) & MNT_ROOTFS) {
                hfsmp->hfs_hotfile_start = blk - (filesize / vcb->blockSize);
                hfsmp->hfs_hotfile_end = hfsmp->hfs_metazone_end;
                hfsmp->hfs_hotfile_freeblks = hfs_hotfile_freeblocks(hfsmp);
        }
        else {
                hfsmp->hfs_hotfile_start = 0;
                hfsmp->hfs_hotfile_end = 0;
                hfsmp->hfs_hotfile_freeblks = 0;
        }
#if DEBUG
        printf("hfs:%s: metadata zone is %d to %d\n", hfsmp->vcbVN, hfsmp->hfs_metazone_start, hfsmp->hfs_metazone_end);
        printf("hfs:%s: hot file band is %d to %d\n", hfsmp->vcbVN, hfsmp->hfs_hotfile_start, hfsmp->hfs_hotfile_end);
        printf("hfs:%s: hot file band free blocks = %d\n", hfsmp->vcbVN, hfsmp->hfs_hotfile_freeblks);
#endif

        hfsmp->hfs_flags |= HFS_METADATA_ZONE;
}


static u_int32_t
hfs_hotfile_freeblocks(struct hfsmount *hfsmp)
{
        ExtendedVCB  *vcb = HFSTOVCB(hfsmp);
        int  lockflags;
        int  freeblocks;

        if (hfsmp->hfs_flags & HFS_CS_HOTFILE_PIN) {
                //
                // This is only used at initialization time and on an ssd
                // we'll get the real info from the hotfile btree user
                // info
                //
                return 0;
        }

        lockflags = hfs_systemfile_lock(hfsmp, SFL_BITMAP, HFS_EXCLUSIVE_LOCK);
        freeblocks = MetaZoneFreeBlocks(vcb);
        hfs_systemfile_unlock(hfsmp, lockflags);

        /* Minus Extents overflow file reserve. */
        if ((uint32_t)hfsmp->hfs_overflow_maxblks >= VTOF(hfsmp->hfs_extents_vp)->ff_blocks) {
                freeblocks -= hfsmp->hfs_overflow_maxblks - VTOF(hfsmp->hfs_extents_vp)->ff_blocks;
        }

        /* Minus catalog file reserve. */
        if ((uint32_t)hfsmp->hfs_catalog_maxblks >= VTOF(hfsmp->hfs_catalog_vp)->ff_blocks) {
                freeblocks -= hfsmp->hfs_catalog_maxblks - VTOF(hfsmp->hfs_catalog_vp)->ff_blocks;
        }
        
        if (freeblocks < 0)
                freeblocks = 0;

        // printf("hfs: hotfile_freeblocks: MIN(%d, %d) = %d\n", freeblocks, hfsmp->hfs_hotfile_maxblks, MIN(freeblocks, hfsmp->hfs_hotfile_maxblks));
        return MIN(freeblocks, hfsmp->hfs_hotfile_maxblks);
}

/*
 * Determine if a file is a "virtual" metadata file.
 * This includes journal and quota files.
 */
int
hfs_virtualmetafile(struct cnode *cp)
{
        const char * filename;


        if (cp->c_parentcnid != kHFSRootFolderID)
                return (0);

        filename = (const char *)cp->c_desc.cd_nameptr;
        if (filename == NULL)
                return (0);

        if ((strncmp(filename, ".journal", sizeof(".journal")) == 0) ||
            (strncmp(filename, ".journal_info_block", sizeof(".journal_info_block")) == 0) ||
            (strncmp(filename, ".quota.user", sizeof(".quota.user")) == 0) ||
            (strncmp(filename, ".quota.group", sizeof(".quota.group")) == 0) ||
            (strncmp(filename, ".hotfiles.btree", sizeof(".hotfiles.btree")) == 0))
                return (1);

        return (0);
}

void hfs_syncer_lock(struct hfsmount *hfsmp)
{
    hfs_lock_mount(hfsmp);
}

void hfs_syncer_unlock(struct hfsmount *hfsmp)
{
    hfs_unlock_mount(hfsmp);
}

void hfs_syncer_wait(struct hfsmount *hfsmp, struct timespec *ts)
{
    msleep(&hfsmp->hfs_syncer_thread, &hfsmp->hfs_mutex, PWAIT,
           "hfs_syncer_wait", ts);
}

void hfs_syncer_wakeup(struct hfsmount *hfsmp)
{
    wakeup(&hfsmp->hfs_syncer_thread);
}

uint64_t hfs_usecs_to_deadline(uint64_t usecs)
{
    uint64_t deadline;
    clock_interval_to_deadline(usecs, NSEC_PER_USEC, &deadline);
    return deadline;
}

//
// Fire off a timed callback to sync the disk if the
// volume is on ejectable media.
//
void hfs_sync_ejectable(struct hfsmount *hfsmp)
{
    // If we don't have a syncer or we get called by the syncer, just return
    if (!ISSET(hfsmp->hfs_flags, HFS_RUN_SYNCER)
                || current_thread() == hfsmp->hfs_syncer_thread) {
        return;
        }

    hfs_syncer_lock(hfsmp);

    if (!timerisset(&hfsmp->hfs_sync_req_oldest))
        microuptime(&hfsmp->hfs_sync_req_oldest);

    /* If hfs_unmount is running, it will clear the HFS_RUN_SYNCER
           flag. Also, we don't want to queue again if there is a sync
           outstanding. */
    if (!ISSET(hfsmp->hfs_flags, HFS_RUN_SYNCER)
                || hfsmp->hfs_syncer_thread) {
        hfs_syncer_unlock(hfsmp);
        return;
    }

    hfsmp->hfs_syncer_thread = (void *)1;

    hfs_syncer_unlock(hfsmp);

        kernel_thread_start(hfs_syncer, hfsmp, &hfsmp->hfs_syncer_thread);
        thread_deallocate(hfsmp->hfs_syncer_thread);
}

int
hfs_start_transaction(struct hfsmount *hfsmp)
{
        int ret = 0, unlock_on_err = 0;
        thread_t thread = current_thread();

#ifdef HFS_CHECK_LOCK_ORDER
        /*
         * You cannot start a transaction while holding a system
         * file lock. (unless the transaction is nested.)
         */
        if (hfsmp->jnl && journal_owner(hfsmp->jnl) != thread) {
                if (hfsmp->hfs_catalog_cp && hfsmp->hfs_catalog_cp->c_lockowner == thread) {
                        panic("hfs_start_transaction: bad lock order (cat before jnl)\n");
                }
                if (hfsmp->hfs_attribute_cp && hfsmp->hfs_attribute_cp->c_lockowner == thread) {
                        panic("hfs_start_transaction: bad lock order (attr before jnl)\n");
                }
                if (hfsmp->hfs_extents_cp && hfsmp->hfs_extents_cp->c_lockowner == thread) {
                        panic("hfs_start_transaction: bad lock order (ext before jnl)\n");
                }
        }
#endif /* HFS_CHECK_LOCK_ORDER */

again:

        if (hfsmp->jnl) {
                if (journal_owner(hfsmp->jnl) != thread) {
                        /*
                         * The global lock should be held shared if journal is 
                         * active to prevent disabling.  If we're not the owner 
                         * of the journal lock, verify that we're not already
                         * holding the global lock exclusive before moving on.   
                         */
                        if (hfsmp->hfs_global_lockowner == thread) {
                                ret = EBUSY;
                                goto out;
                        }

                        hfs_lock_global (hfsmp, HFS_SHARED_LOCK);

                        // Things could have changed
                        if (!hfsmp->jnl) {
                                hfs_unlock_global(hfsmp);
                                goto again;
                        }

                        OSAddAtomic(1, (SInt32 *)&hfsmp->hfs_active_threads);
                        unlock_on_err = 1;
                }
        } else {
                // No journal
                if (hfsmp->hfs_global_lockowner != thread) {
                        hfs_lock_global(hfsmp, HFS_EXCLUSIVE_LOCK);

                        // Things could have changed
                        if (hfsmp->jnl) {
                                hfs_unlock_global(hfsmp);
                                goto again;
                        }

                        OSAddAtomic(1, (SInt32 *)&hfsmp->hfs_active_threads);
                        unlock_on_err = 1;
                }
        }

        /* If a downgrade to read-only mount is in progress, no other
         * thread than the downgrade thread is allowed to modify 
         * the file system.
         */
        if ((hfsmp->hfs_flags & HFS_RDONLY_DOWNGRADE) && 
            hfsmp->hfs_downgrading_thread != thread) {
                ret = EROFS;
                goto out;
        }

        if (hfsmp->jnl) {
                ret = journal_start_transaction(hfsmp->jnl);
        } else {
                ret = 0;
        }

        if (ret == 0)
                ++hfsmp->hfs_transaction_nesting;

out:
        if (ret != 0 && unlock_on_err) {
                hfs_unlock_global (hfsmp);
                OSAddAtomic(-1, (SInt32 *)&hfsmp->hfs_active_threads);
        }

    return ret;
}

int
hfs_end_transaction(struct hfsmount *hfsmp)
{
    int ret;

        hfs_assert(!hfsmp->jnl || journal_owner(hfsmp->jnl) == current_thread());
        hfs_assert(hfsmp->hfs_transaction_nesting > 0);

        if (hfsmp->jnl && hfsmp->hfs_transaction_nesting == 1)
                hfs_flushvolumeheader(hfsmp, HFS_FVH_FLUSH_IF_DIRTY);

        bool need_unlock = !--hfsmp->hfs_transaction_nesting;

        if (hfsmp->jnl) {
                ret = journal_end_transaction(hfsmp->jnl);
        } else {
                ret = 0;
        }

        if (need_unlock) {
                OSAddAtomic(-1, (SInt32 *)&hfsmp->hfs_active_threads);
                hfs_unlock_global (hfsmp);
                hfs_sync_ejectable(hfsmp);
        }

    return ret;
}


void 
hfs_journal_lock(struct hfsmount *hfsmp) 
{
        /* Only peek at hfsmp->jnl while holding the global lock */
        hfs_lock_global (hfsmp, HFS_SHARED_LOCK);
        if (hfsmp->jnl) {
                journal_lock(hfsmp->jnl);
        }
        hfs_unlock_global (hfsmp);
}

void 
hfs_journal_unlock(struct hfsmount *hfsmp) 
{
        /* Only peek at hfsmp->jnl while holding the global lock */
        hfs_lock_global (hfsmp, HFS_SHARED_LOCK);
        if (hfsmp->jnl) {
                journal_unlock(hfsmp->jnl);
        }
        hfs_unlock_global (hfsmp);
}

/*
 * Flush the contents of the journal to the disk.
 *
 *  - HFS_FLUSH_JOURNAL
 *      Wait to write in-memory journal to the disk consistently.
 *      This means that the journal still contains uncommitted
 *      transactions and the file system metadata blocks in
 *      the journal transactions might be written asynchronously
 *      to the disk.  But there is no guarantee that they are
 *      written to the disk before returning to the caller.
 *      Note that this option is sufficient for file system
 *      data integrity as it guarantees consistent journal
 *      content on the disk.
 *
 *  - HFS_FLUSH_JOURNAL_META
 *      Wait to write in-memory journal to the disk
 *      consistently, and also wait to write all asynchronous
 *      metadata blocks to its corresponding locations
 *      consistently on the disk. This is overkill in normal
 *      scenarios but is useful whenever the metadata blocks
 *      are required to be consistent on-disk instead of
 *      just the journalbeing consistent; like before live
 *      verification and live volume resizing.  The update of the
 *      metadata doesn't include a barrier of track cache flush.
 *
 *  - HFS_FLUSH_FULL
 *      HFS_FLUSH_JOURNAL + force a track cache flush to media
 *
 *  - HFS_FLUSH_CACHE
 *      Force a track cache flush to media.
 *
 *  - HFS_FLUSH_BARRIER
 *      Barrier-only flush to ensure write order
 *
 */
errno_t hfs_flush(struct hfsmount *hfsmp, hfs_flush_mode_t mode)
{
        errno_t error = 0;
        int options = 0;
        dk_synchronize_t sync_req = { .options = DK_SYNCHRONIZE_OPTION_BARRIER };

        switch (mode) {
                case HFS_FLUSH_JOURNAL_META:
                        // wait for journal, metadata blocks and previous async flush to finish
                        SET(options, JOURNAL_WAIT_FOR_IO);

                        // no break

                case HFS_FLUSH_JOURNAL:
                case HFS_FLUSH_JOURNAL_BARRIER:
                case HFS_FLUSH_FULL:

                        if (mode == HFS_FLUSH_JOURNAL_BARRIER &&
                            !(hfsmp->hfs_flags & HFS_FEATURE_BARRIER))
                                mode = HFS_FLUSH_FULL;

                        if (mode == HFS_FLUSH_FULL)
                                SET(options, JOURNAL_FLUSH_FULL);

                        /* Only peek at hfsmp->jnl while holding the global lock */
                        hfs_lock_global (hfsmp, HFS_SHARED_LOCK);

                        if (hfsmp->jnl)
                                error = journal_flush(hfsmp->jnl, options);

                        hfs_unlock_global (hfsmp);

                        /*
                         * This may result in a double barrier as
                         * journal_flush may have issued a barrier itself
                         */
                        if (mode == HFS_FLUSH_JOURNAL_BARRIER)
                                error = VNOP_IOCTL(hfsmp->hfs_devvp,
                                    DKIOCSYNCHRONIZE, (caddr_t)&sync_req,
                                    FWRITE, NULL);

                        break;

                case HFS_FLUSH_CACHE:
                        // Do a full sync
                        sync_req.options = 0;

                        // no break

                case HFS_FLUSH_BARRIER:
                        // If barrier only flush doesn't support, fall back to use full flush.
                        if (!(hfsmp->hfs_flags & HFS_FEATURE_BARRIER))
                                sync_req.options = 0;

                        error = VNOP_IOCTL(hfsmp->hfs_devvp, DKIOCSYNCHRONIZE, (caddr_t)&sync_req,
                                           FWRITE, NULL);
                        break;

                default:
                        error = EINVAL;
        }

        return error;
}

/*
 * hfs_erase_unused_nodes
 *
 * Check wheter a volume may suffer from unused Catalog B-tree nodes that
 * are not zeroed (due to <rdar://problem/6947811>).  If so, just write
 * zeroes to the unused nodes.
 *
 * How do we detect when a volume needs this repair?  We can't always be
 * certain.  If a volume was created after a certain date, then it may have
 * been created with the faulty newfs_hfs.  Since newfs_hfs only created one
 * clump, we can assume that if a Catalog B-tree is larger than its clump size,
 * that means that the entire first clump must have been written to, which means
 * there shouldn't be unused and unwritten nodes in that first clump, and this
 * repair is not needed.
 *
 * We have defined a bit in the Volume Header's attributes to indicate when the
 * unused nodes have been repaired.  A newer newfs_hfs will set this bit.
 * As will fsck_hfs when it repairs the unused nodes.
 */
int hfs_erase_unused_nodes(struct hfsmount *hfsmp)
{
        int result; 
        struct filefork *catalog;
        int lockflags;
        
        if (hfsmp->vcbAtrb & kHFSUnusedNodeFixMask)
        {
                /* This volume has already been checked and repaired. */
                return 0;
        }

        if ((hfsmp->localCreateDate < kHFSUnusedNodesFixDate))
        {
                /* This volume is too old to have had the problem. */
                hfsmp->vcbAtrb |= kHFSUnusedNodeFixMask;
                return 0;
        }

        catalog = hfsmp->hfs_catalog_cp->c_datafork;
        if (catalog->ff_size > catalog->ff_clumpsize)
        {
                /* The entire first clump must have been in use at some point. */
                hfsmp->vcbAtrb |= kHFSUnusedNodeFixMask;
                return 0;
        }
        
        /*
         * If we get here, we need to zero out those unused nodes.
         *
         * We start a transaction and lock the catalog since we're going to be
         * making on-disk changes.  But note that BTZeroUnusedNodes doens't actually
         * do its writing via the journal, because that would be too much I/O
         * to fit in a transaction, and it's a pain to break it up into multiple
         * transactions.  (It behaves more like growing a B-tree would.)
         */
        printf("hfs_erase_unused_nodes: updating volume %s.\n", hfsmp->vcbVN);
        result = hfs_start_transaction(hfsmp);
        if (result)
                goto done;
        lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG, HFS_EXCLUSIVE_LOCK);
        result = BTZeroUnusedNodes(catalog);
        vnode_waitforwrites(hfsmp->hfs_catalog_vp, 0, 0, 0, "hfs_erase_unused_nodes");
        hfs_systemfile_unlock(hfsmp, lockflags);
        hfs_end_transaction(hfsmp);
        if (result == 0)
                hfsmp->vcbAtrb |= kHFSUnusedNodeFixMask;
        printf("hfs_erase_unused_nodes: done updating volume %s.\n", hfsmp->vcbVN);

done:
        return result;
}


int
check_for_dataless_file(struct vnode *vp, uint64_t op_type)
{
        int error;

        if (vp == NULL || (VTOC(vp)->c_bsdflags & UF_COMPRESSED) == 0 || VTOCMP(vp) == NULL || decmpfs_cnode_cmp_type(VTOCMP(vp)) != DATALESS_CMPFS_TYPE) {
                // there's nothing to do, it's not dataless
                return 0;
        }

        /* Swap files are special; ignore them */
        if (vnode_isswap(vp)) {
                return 0;       
        }

        // printf("hfs: dataless: encountered a file with the dataless bit set! (vp %p)\n", vp);
        error = resolve_nspace_item(vp, op_type | NAMESPACE_HANDLER_NSPACE_EVENT);
        if (error == EDEADLK && op_type == NAMESPACE_HANDLER_WRITE_OP) {
                error = 0;
        } else if (error) {
                if (error == EAGAIN) {
                        printf("hfs: dataless: timed out waiting for namespace handler...\n");
                        // XXXdbg - return the fabled ENOTPRESENT (i.e. EJUKEBOX)?
                        return 0;                               
                } else if (error == EINTR) {
                        // printf("hfs: dataless: got a signal while waiting for namespace handler...\n");
                        return EINTR;
                }
        } else if (VTOC(vp)->c_bsdflags & UF_COMPRESSED) {
                //
                // if we're here, the dataless bit is still set on the file 
                // which means it didn't get handled.  we return an error
                // but it's presently ignored by all callers of this function.
                //
                // XXXdbg - EDATANOTPRESENT is what we really need...
                //
                return EBADF;
        }                               

        return error;
}


//
// NOTE: this function takes care of starting a transaction and
//       acquiring the systemfile lock so that it can call
//       cat_update().
//
// NOTE: do NOT hold and cnode locks while calling this function
//       to avoid deadlocks (because we take a lock on the root
//       cnode)
//
int
hfs_generate_document_id(struct hfsmount *hfsmp, uint32_t *docid)
{
        struct vnode *rvp;
        struct cnode *cp;
        int error;

        error = hfs_vfs_root(HFSTOVFS(hfsmp), &rvp, vfs_context_kernel());
        if (error) {
                return error;
        }

        cp = VTOC(rvp);
        if ((error = hfs_lock(cp, HFS_EXCLUSIVE_LOCK, HFS_LOCK_DEFAULT)) != 0) {
                return error;
        }
        struct FndrExtendedDirInfo *extinfo = (struct FndrExtendedDirInfo *)((void *)((char *)&cp->c_attr.ca_finderinfo + 16));
        
        int lockflags;
        if ((error = hfs_start_transaction(hfsmp)) != 0) {
                return error;
        }
        lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG, HFS_EXCLUSIVE_LOCK);
                                        
        if (extinfo->document_id == 0) {
                // initialize this to start at 3 (one greater than the root-dir id)
                extinfo->document_id = 3;
        }

        *docid = extinfo->document_id++;

        // mark the root cnode dirty
        cp->c_flag |= C_MODIFIED;
        hfs_update(cp->c_vp, 0);

        hfs_systemfile_unlock (hfsmp, lockflags);
        (void) hfs_end_transaction(hfsmp);
                
        (void) hfs_unlock(cp);

        vnode_put(rvp);
        rvp = NULL;

        return 0;
}


/* 
 * Return information about number of file system allocation blocks 
 * taken by metadata on a volume.  
 *  
 * This function populates struct hfsinfo_metadata with allocation blocks 
 * used by extents overflow btree, catalog btree, bitmap, attribute btree, 
 * journal file, and sum of all of the above.  
 */
int 
hfs_getinfo_metadata_blocks(struct hfsmount *hfsmp, struct hfsinfo_metadata *hinfo)
{
        int lockflags = 0;
        int ret_lockflags = 0;

        /* Zero out the output buffer */
        bzero(hinfo, sizeof(struct hfsinfo_metadata));

        /* 
         * Getting number of allocation blocks for all btrees 
         * should be a quick operation, so we grab locks for 
         * all of them at the same time
         */
        lockflags = SFL_CATALOG | SFL_EXTENTS | SFL_BITMAP | SFL_ATTRIBUTE;
        ret_lockflags = hfs_systemfile_lock(hfsmp, lockflags, HFS_EXCLUSIVE_LOCK);
        /* 
         * Make sure that we were able to acquire all locks requested 
         * to protect us against conditions like unmount in progress.
         */
        if ((lockflags & ret_lockflags) != lockflags) {
                /* Release any locks that were acquired */
                hfs_systemfile_unlock(hfsmp, ret_lockflags);
                return EPERM;
        }

        /* Get information about all the btrees */
        hinfo->extents = hfsmp->hfs_extents_cp->c_datafork->ff_blocks;
        hinfo->catalog = hfsmp->hfs_catalog_cp->c_datafork->ff_blocks;
        hinfo->allocation = hfsmp->hfs_allocation_cp->c_datafork->ff_blocks;
        hinfo->attribute = hfsmp->hfs_attribute_cp->c_datafork->ff_blocks;

        /* Done with btrees, give up the locks */
        hfs_systemfile_unlock(hfsmp, ret_lockflags);

        /* Get information about journal file */
        hinfo->journal = howmany(hfsmp->jnl_size, hfsmp->blockSize);

        /* Calculate total number of metadata blocks */
        hinfo->total = hinfo->extents + hinfo->catalog + 
                        hinfo->allocation + hinfo->attribute +
                        hinfo->journal;
        
        return 0;
}

static int
hfs_freezewrite_callback(struct vnode *vp, __unused void *cargs)
{
        vnode_waitforwrites(vp, 0, 0, 0, "hfs freeze 8");

        return 0;
}

int hfs_freeze(struct hfsmount *hfsmp)
{
        // First make sure some other process isn't freezing
        hfs_lock_mount(hfsmp);
        while (hfsmp->hfs_freeze_state != HFS_THAWED) {
                if (msleep(&hfsmp->hfs_freeze_state, &hfsmp->hfs_mutex,
                                   PWAIT | PCATCH, "hfs freeze 1", NULL) == EINTR) {
                        hfs_unlock_mount(hfsmp);
                        return EINTR;
                }
        }

        // Stop new syncers from starting
        hfsmp->hfs_freeze_state = HFS_WANT_TO_FREEZE;

        // Now wait for all syncers to finish
        while (hfsmp->hfs_syncers) {
                if (msleep(&hfsmp->hfs_freeze_state, &hfsmp->hfs_mutex,
                           PWAIT | PCATCH, "hfs freeze 2", NULL) == EINTR) {
                        hfs_thaw_locked(hfsmp);
                        hfs_unlock_mount(hfsmp);
                        return EINTR;                           
                }
        }
        hfs_unlock_mount(hfsmp);

        // flush things before we get started to try and prevent
        // dirty data from being paged out while we're frozen.
        // note: we can't do this once we're in the freezing state because
        // other threads will need to take the global lock
        vnode_iterate(hfsmp->hfs_mp, 0, hfs_freezewrite_callback, NULL);

        // Block everything in hfs_lock_global now
        hfs_lock_mount(hfsmp);
        hfsmp->hfs_freeze_state = HFS_FREEZING;
        hfsmp->hfs_freezing_thread = current_thread();
        hfs_unlock_mount(hfsmp);

        /* Take the exclusive lock to flush out anything else that
           might have the global lock at the moment and also so we
           can flush the journal. */
        hfs_lock_global(hfsmp, HFS_EXCLUSIVE_LOCK);
        journal_flush(hfsmp->jnl, JOURNAL_WAIT_FOR_IO);
        hfs_unlock_global(hfsmp);

        // don't need to iterate on all vnodes, we just need to
        // wait for writes to the system files and the device vnode
        //
        // Now that journal flush waits for all metadata blocks to 
        // be written out, waiting for btree writes is probably no
        // longer required.
        if (HFSTOVCB(hfsmp)->extentsRefNum)
                vnode_waitforwrites(HFSTOVCB(hfsmp)->extentsRefNum, 0, 0, 0, "hfs freeze 3");
        if (HFSTOVCB(hfsmp)->catalogRefNum)
                vnode_waitforwrites(HFSTOVCB(hfsmp)->catalogRefNum, 0, 0, 0, "hfs freeze 4");
        if (HFSTOVCB(hfsmp)->allocationsRefNum)
                vnode_waitforwrites(HFSTOVCB(hfsmp)->allocationsRefNum, 0, 0, 0, "hfs freeze 5");
        if (hfsmp->hfs_attribute_vp)
                vnode_waitforwrites(hfsmp->hfs_attribute_vp, 0, 0, 0, "hfs freeze 6");
        vnode_waitforwrites(hfsmp->hfs_devvp, 0, 0, 0, "hfs freeze 7");

        // We're done, mark frozen
        hfs_lock_mount(hfsmp);
        hfsmp->hfs_freeze_state  = HFS_FROZEN;
        hfsmp->hfs_freezing_proc = current_proc();
        hfs_unlock_mount(hfsmp);

        return 0;
}

int hfs_thaw(struct hfsmount *hfsmp, const struct proc *process)
{
        hfs_lock_mount(hfsmp);

        if (hfsmp->hfs_freeze_state != HFS_FROZEN) {
                hfs_unlock_mount(hfsmp);
                return EINVAL;
        }
        if (process && hfsmp->hfs_freezing_proc != process) {
                hfs_unlock_mount(hfsmp);
                return EPERM;
        }

        hfs_thaw_locked(hfsmp);

        hfs_unlock_mount(hfsmp);

        return 0;
}

static void hfs_thaw_locked(struct hfsmount *hfsmp)
{
        hfsmp->hfs_freezing_proc = NULL;
        hfsmp->hfs_freeze_state = HFS_THAWED;

        wakeup(&hfsmp->hfs_freeze_state);
}

uintptr_t obfuscate_addr(void *addr)
{
        vm_offset_t new_addr;
        vm_kernel_addrperm_external((vm_offset_t)addr, &new_addr);
        return new_addr;
}

#if CONFIG_HFS_STD
/*
 * Convert HFS encoded string into UTF-8
 *
 * Unicode output is fully decomposed
 * '/' chars are converted to ':'
 */
int
hfs_to_utf8(ExtendedVCB *vcb, const Str31 hfs_str, ByteCount maxDstLen, ByteCount *actualDstLen, unsigned char* dstStr)
{
        int error;
        UniChar uniStr[MAX_HFS_UNICODE_CHARS];
        ItemCount uniCount;
        size_t utf8len;
        hfs_to_unicode_func_t hfs_get_unicode = VCBTOHFS(vcb)->hfs_get_unicode;
        u_int8_t pascal_length = 0;

        /*
         * Validate the length of the Pascal-style string before passing it
         * down to the decoding engine.
         */
        pascal_length = *((const u_int8_t*)(hfs_str));
        if (pascal_length > 31) {
                /* invalid string; longer than 31 bytes */
                error = EINVAL;
                return error;
        }

        error = hfs_get_unicode(hfs_str, uniStr, MAX_HFS_UNICODE_CHARS, &uniCount);

        if (uniCount == 0)
                error = EINVAL;

        if (error == 0) {
                error = utf8_encodestr(uniStr, uniCount * sizeof(UniChar), dstStr, &utf8len, maxDstLen , ':', 0);
                if (error == ENAMETOOLONG)
                        *actualDstLen = utf8_encodelen(uniStr, uniCount * sizeof(UniChar), ':', 0);
                else
                        *actualDstLen = utf8len;
        }

        return error;
}

/*
 * Convert UTF-8 string into HFS encoding
 *
 * ':' chars are converted to '/'
 * Assumes input represents fully decomposed Unicode
 */
int
utf8_to_hfs(ExtendedVCB *vcb, ByteCount srcLen, const unsigned char* srcStr, Str31 dstStr/*, int retry*/)
{
        int error;
        UniChar uniStr[MAX_HFS_UNICODE_CHARS];
        size_t ucslen;

        error = utf8_decodestr(srcStr, srcLen, uniStr, &ucslen, sizeof(uniStr), ':', 0);
        if (error == 0)
                error = unicode_to_hfs(vcb, ucslen, uniStr, dstStr, 1);

        return error;
}

/*
 * Convert Unicode string into HFS encoding
 *
 * ':' chars are converted to '/'
 * Assumes input represents fully decomposed Unicode
 */
int
unicode_to_hfs(ExtendedVCB *vcb, ByteCount srcLen, u_int16_t* srcStr, Str31 dstStr, int retry)
{
        int error;
        unicode_to_hfs_func_t hfs_get_hfsname = VCBTOHFS(vcb)->hfs_get_hfsname;

        error = hfs_get_hfsname(srcStr, srcLen/sizeof(UniChar), dstStr);
        if (error && retry) {
                error = unicode_to_mac_roman(srcStr, srcLen/sizeof(UniChar), dstStr);
        }
        return error;
}

#endif // CONFIG_HFS_STD

static uint64_t hfs_allocated __attribute__((aligned(8)));

#if HFS_MALLOC_DEBUG

#warning HFS_MALLOC_DEBUG is on

#include <libkern/OSDebug.h>
#include "hfs_alloc_trace.h"

struct alloc_debug_header {
        uint32_t magic;
        uint32_t size;
        uint64_t sequence;
        LIST_ENTRY(alloc_debug_header) chain;
        void *backtrace[HFS_ALLOC_BACKTRACE_LEN];
};

enum {
        HFS_ALLOC_MAGIC = 0x68667361,   // "hfsa"
        HFS_ALLOC_DEAD  = 0x68667364,   // "hfsd"
};

static LIST_HEAD(, alloc_debug_header) hfs_alloc_list;
static lck_mtx_t *hfs_alloc_mtx;
static int hfs_alloc_tracing;
static uint64_t hfs_alloc_sequence;

void hfs_alloc_trace_enable(void)
{
        if (hfs_alloc_tracing)
                return;

        // Not thread-safe, but this is debug so who cares
        extern lck_grp_t *hfs_mutex_group;
        extern lck_attr_t *hfs_lock_attr;

        if (!hfs_alloc_mtx) {
                hfs_alloc_mtx = lck_mtx_alloc_init(hfs_mutex_group, hfs_lock_attr);
                LIST_INIT(&hfs_alloc_list);
        }

        // Using OSCompareAndSwap in lieu of a barrier
        OSCompareAndSwap(hfs_alloc_tracing, true, &hfs_alloc_tracing);
}

void hfs_alloc_trace_disable(void)
{
        if (!hfs_alloc_tracing)
                return;

        hfs_alloc_tracing = false;

        lck_mtx_lock_spin(hfs_alloc_mtx);

        struct alloc_debug_header *hdr;
        LIST_FOREACH(hdr, &hfs_alloc_list, chain) {
                hdr->chain.le_prev = NULL;
        }
        LIST_INIT(&hfs_alloc_list);

        lck_mtx_unlock(hfs_alloc_mtx);
}

static int hfs_handle_alloc_tracing SYSCTL_HANDLER_ARGS
{
        int v = hfs_alloc_tracing;

        int err = sysctl_handle_int(oidp, &v, 0, req);
        if (err || req->newptr == USER_ADDR_NULL || v == hfs_alloc_tracing)
                return err;

        if (v)
                hfs_alloc_trace_enable();
        else
                hfs_alloc_trace_disable();

        return 0;
}

HFS_SYSCTL(PROC, _vfs_generic_hfs, OID_AUTO, alloc_tracing,
                   CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED, NULL, 0,
                   hfs_handle_alloc_tracing, "I", "Allocation tracing")

static int hfs_handle_alloc_trace_info SYSCTL_HANDLER_ARGS
{
        if (!hfs_alloc_tracing) {
                struct hfs_alloc_trace_info info = {};
                return sysctl_handle_opaque(oidp, &info, sizeof(info), req);
        }

        const int size = 128 * 1024;
        struct hfs_alloc_trace_info *info = kalloc(size);

        const int max_entries = ((size - sizeof(*info))
                                                         / sizeof(struct hfs_alloc_info_entry));

        info->entry_count = 0;
        info->more = false;

        lck_mtx_lock_spin(hfs_alloc_mtx);

        struct alloc_debug_header *hdr;
        LIST_FOREACH(hdr, &hfs_alloc_list, chain) {
                if (info->entry_count == max_entries) {
                        info->more = true;
                        break;
                }
                vm_offset_t o;
                vm_kernel_addrperm_external((vm_offset_t)hdr, &o);
                info->entries[info->entry_count].ptr = o;
                info->entries[info->entry_count].size = hdr->size;
                info->entries[info->entry_count].sequence = hdr->sequence;
                for (int i = 0; i < HFS_ALLOC_BACKTRACE_LEN; ++i) {
                        vm_kernel_unslide_or_perm_external((vm_offset_t)hdr->backtrace[i], &o);
                        info->entries[info->entry_count].backtrace[i] = o;
                }
                ++info->entry_count;
        }

        lck_mtx_unlock(hfs_alloc_mtx);

        int err = sysctl_handle_opaque(oidp, info,
                                                                   sizeof(*info) + info->entry_count
                                                                   * sizeof(struct hfs_alloc_info_entry),
                                                                   req);

        kfree(info, size);

        return err;
}

HFS_SYSCTL(PROC, _vfs_generic_hfs, OID_AUTO, alloc_trace_info,
                   CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_LOCKED, NULL, 0,
                   hfs_handle_alloc_trace_info, "-", "Allocation trace info")

bool hfs_dump_allocations(void)
{
        if (!hfs_allocated)
                return false;

        lck_mtx_lock(hfs_alloc_mtx);

        struct alloc_debug_header *hdr;
        LIST_FOREACH(hdr, &hfs_alloc_list, chain) {
                vm_offset_t o;
                vm_kernel_addrperm_external((vm_offset_t)hdr, &o);
                printf(" -- 0x%lx:%llu <%u> --\n", o, hdr->sequence, hdr->size);
                for (int j = 0; j < HFS_ALLOC_BACKTRACE_LEN && hdr->backtrace[j]; ++j) {
                        vm_kernel_unslide_or_perm_external((vm_offset_t)hdr->backtrace[j], &o);
                        printf("0x%lx\n", o);
                }
        }

        lck_mtx_unlock(hfs_alloc_mtx);

        return true;
}

#endif

HFS_SYSCTL(QUAD, _vfs_generic_hfs, OID_AUTO, allocated,
                   CTLFLAG_RD | CTLFLAG_LOCKED, &hfs_allocated, "Memory allocated")

// Any allocation >= PAGE_SIZE will be page aligned
void *hfs_malloc(size_t size)
{
#if HFS_MALLOC_DEBUG
        hfs_assert(size <= 0xffffffff);

        struct alloc_debug_header *hdr;

        void *ptr;

        if (size >= PAGE_SIZE)
                ptr = IOMallocAligned(size + sizeof(*hdr), PAGE_SIZE);
        else
                ptr = kalloc(size + sizeof(*hdr));

        hdr = ptr + size;

        hdr->magic = HFS_ALLOC_MAGIC;
        hdr->size = size;

        if (hfs_alloc_tracing) {
                OSBacktrace(hdr->backtrace, HFS_ALLOC_BACKTRACE_LEN);
                lck_mtx_lock_spin(hfs_alloc_mtx);
                LIST_INSERT_HEAD(&hfs_alloc_list, hdr, chain);
                hdr->sequence = ++hfs_alloc_sequence;
                lck_mtx_unlock(hfs_alloc_mtx);
        } else
                hdr->chain.le_prev = NULL;
#else
        void *ptr;
        if (size >= PAGE_SIZE)
                ptr = IOMallocAligned(size, PAGE_SIZE);
        else
                ptr = kalloc(size);
#endif

        OSAddAtomic64(size, &hfs_allocated);

        return ptr;
}

void hfs_free(void *ptr, size_t size)
{
        if (!ptr)
                return;

        OSAddAtomic64(-(int64_t)size, &hfs_allocated);

#if HFS_MALLOC_DEBUG
        struct alloc_debug_header *hdr = ptr + size;

        hfs_assert(hdr->magic == HFS_ALLOC_MAGIC);
        hfs_assert(hdr->size == size);

        hdr->magic = HFS_ALLOC_DEAD;

        if (hdr->chain.le_prev) {
                lck_mtx_lock_spin(hfs_alloc_mtx);
                LIST_REMOVE(hdr, chain);
                lck_mtx_unlock(hfs_alloc_mtx);
        }

        if (size >= PAGE_SIZE)
                IOFreeAligned(ptr, size + sizeof(*hdr));
        else
                kfree(ptr, size + sizeof(*hdr));
#else
        if (size >= PAGE_SIZE)
                IOFreeAligned(ptr, size);
        else
                kfree(ptr, size);
#endif
}

void *hfs_mallocz(size_t size)
{
        void *ptr = hfs_malloc(size);
        bzero(ptr, size);
        return ptr;
}

struct hfs_sysctl_chain *sysctl_list;

void hfs_sysctl_register(void)
{
        struct hfs_sysctl_chain *e = sysctl_list;
        while (e) {
                sysctl_register_oid(e->oid);
                e = e->next;
        }
}

void hfs_sysctl_unregister(void)
{
        struct hfs_sysctl_chain *e = sysctl_list;
        while (e) {
                sysctl_unregister_oid(e->oid);
                e = e->next;
        }
}

void hfs_assert_fail(const char *file, unsigned line, const char *expr)
{
        Assert(file, line, expr);
        __builtin_unreachable();
}