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

/*
 * Copyright (c) 2000-2007 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*      @(#)hfs_vfsutils.c      4.0
*
*       (c) 1997-2002 Apple Computer, 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/buf.h>
#include <sys/buf_internal.h>
#include <sys/ubc.h>
#include <sys/unistd.h>
#include <sys/utfconv.h>
#include <sys/kauth.h>
#include <sys/fcntl.h>
#include <sys/vnode_internal.h>

#include <libkern/OSAtomic.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 "hfscommon/headers/FileMgrInternal.h"
#include "hfscommon/headers/BTreesInternal.h"
#include "hfscommon/headers/HFSUnicodeWrappers.h"

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

static void hfs_metadatazone_init(struct hfsmount *);
static u_int32_t hfs_hotfile_freeblocks(struct hfsmount *);


//*******************************************************************************
// 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";


__private_extern__
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;

        /* 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->vcbCrDate          = 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))
                (void) mac_roman_to_utf8(mdb->drVN, NAME_MAX, &utf8chars, vcb->vcbVN);

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

        hfsmp->hfs_alt_id_sector = HFS_ALT_SECTOR(hfsmp->hfs_logical_block_size,
                                                  hfsmp->hfs_logical_block_count);

        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);
        if (error) goto MtVolErr;
        error = MacToVFSError(BTOpenPath(VTOF(hfsmp->hfs_extents_vp),
                                         (KeyCompareProcPtr)CompareExtentKeys));
        if (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);
        if (error) {
                hfs_unlock(VTOC(hfsmp->hfs_extents_vp));
                goto MtVolErr;
        }
        error = MacToVFSError(BTOpenPath(VTOF(hfsmp->hfs_catalog_vp),
                                         (KeyCompareProcPtr)CompareCatalogKeys));
        if (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);
        if (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, NULL, NULL, NULL);
      }

    if ( error == noErr )
      {
        if ( !(vcb->vcbAtrb & kHFSVolumeHardwareLockMask) )             //      if the disk is not write protected
          {
            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));

    goto        CmdDone;

    //--        Release any resources allocated so far before exiting with an error:
MtVolErr:
        ReleaseMetaFileVNode(hfsmp->hfs_catalog_vp);
        ReleaseMetaFileVNode(hfsmp->hfs_extents_vp);

CmdDone:
    return (error);
}

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

__private_extern__
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  i;
        OSErr retval;

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

        if (signature == kHFSPlusSigWord) {
                if (hfs_version != kHFSPlusVersion) {
                        printf("hfs_mount: invalid HFS+ version: %d\n", hfs_version);
                        return (EINVAL);
                }
        } else if (signature == kHFSXSigWord) {
                if (hfs_version != kHFSXVersion) {
                        printf("hfs_mount: invalid HFSX version: %d\n", hfs_version);
                        return (EINVAL);
                }
                /* The in-memory signature is always 'H+'. */
                signature = kHFSPlusSigWord;
                hfsmp->hfs_flags |= HFS_X;
        } else {
                /* Removed printf for invalid HFS+ signature because it gives
                 * false error for UFS root volume 
                 */
                return (EINVAL);
        }

        /* Block size must be at least 512 and a power of 2 */
        blockSize = SWAP_BE32(vhp->blockSize);
        if (blockSize < 512 || !powerof2(blockSize))
                return (EINVAL);
   
        /* 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)
                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)) ||
            (blockSize < hfsmp->hfs_logical_block_size)) {
                return (ENXIO);
        }

        /* If allocation block size is less than the physical 
         * block size, 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 at physical block boundary and will cause 
         * problems if it is less than the 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.
         */
        spare_sectors = hfsmp->hfs_logical_block_count -
                        (((daddr64_t)vcb->totalBlocks * blockSize) /
                           hfsmp->hfs_logical_block_size);

        if (spare_sectors > (daddr64_t)(blockSize / hfsmp->hfs_logical_block_size)) {
                hfsmp->hfs_alt_id_sector = 0;  /* partition has grown! */
        } else {
                hfsmp->hfs_alt_id_sector = (hfsmp->hfsPlusIOPosOffset / hfsmp->hfs_logical_block_size) +
                                           HFS_ALT_SECTOR(hfsmp->hfs_logical_block_size,
                                                          hfsmp->hfs_logical_block_count);
        }

        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);
        if (retval)
        {
                goto ErrorExit;
        }
        hfsmp->hfs_extents_cp = VTOC(hfsmp->hfs_extents_vp);
        hfs_unlock(hfsmp->hfs_extents_cp);

        retval = MacToVFSError(BTOpenPath(VTOF(hfsmp->hfs_extents_vp),
                                          (KeyCompareProcPtr) CompareExtentKeysPlus));
        if (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);
        if (retval) {
                goto ErrorExit;
        }
        hfsmp->hfs_catalog_cp = VTOC(hfsmp->hfs_catalog_vp);
        hfs_unlock(hfsmp->hfs_catalog_cp);

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

        /*
         * 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);
        if (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);
                if (retval) {
                        goto ErrorExit;
                }
                hfsmp->hfs_attribute_cp = VTOC(hfsmp->hfs_attribute_vp);
                hfs_unlock(hfsmp->hfs_attribute_cp);
                retval = MacToVFSError(BTOpenPath(VTOF(hfsmp->hfs_attribute_vp),
                                                  (KeyCompareProcPtr) hfs_attrkeycompare));
                if (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);
                if (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 */
        retval = cat_idlookup(hfsmp, kHFSRootFolderID, 0, &cndesc, &cnattr, NULL);
        if (retval) {
                goto ErrorExit;
        }
        vcb->vcbCrDate = cnattr.ca_itime;
        vcb->volumeNameEncodingHint = cndesc.cd_encoding;
        bcopy(cndesc.cd_nameptr, vcb->vcbVN, min(255, cndesc.cd_namelen));
        cat_releasedesc(&cndesc);

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

        /* 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) {
                        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));

                                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;
                            }
                        }

                        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));
                }
        }

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

        /*
         * 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);
                }
        }

        /* 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);

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

        /*
         * Allow hot file clustering if conditions allow.
         */
        if ((hfsmp->hfs_flags & HFS_METADATA_ZONE)  &&
            ((hfsmp->hfs_flags & HFS_READ_ONLY) == 0)) {
                (void) hfs_recording_init(hfsmp);
        }

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

        /* Check if volume supports writing of extent-based extended attributes */
        hfs_check_volxattr(hfsmp, HFS_SET_XATTREXTENTS_STATE);

        return (0);

ErrorExit:
        /*
         * A fatal error occurred and the volume cannot be mounted
         * release any resources that we aquired...
         */
        if (hfsmp->hfs_attribute_vp)
                ReleaseMetaFileVNode(hfsmp->hfs_attribute_vp);
        ReleaseMetaFileVNode(hfsmp->hfs_allocation_vp);
        ReleaseMetaFileVNode(hfsmp->hfs_catalog_vp);
        ReleaseMetaFileVNode(hfsmp->hfs_extents_vp);

        return (retval);
}


/*
 * 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);
                        (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)
*
*************************************************************/

__private_extern__
int
hfsUnmount( register struct hfsmount *hfsmp, __unused struct proc *p)
{
        /* Get rid of our attribute data vnode (if any). */
        if (hfsmp->hfs_attrdata_vp) {
                vnode_t advp = hfsmp->hfs_attrdata_vp;
        
                if (vnode_get(advp) == 0) {
                        vnode_rele_ext(advp, O_EVTONLY, 0);
                        vnode_put(advp);
                }
                hfsmp->hfs_attrdata_vp = NULLVP;
        }

        if (hfsmp->hfs_startup_vp)
                ReleaseMetaFileVNode(hfsmp->hfs_startup_vp);

        if (hfsmp->hfs_allocation_vp)
                ReleaseMetaFileVNode(hfsmp->hfs_allocation_vp);

        if (hfsmp->hfs_attribute_vp)
                ReleaseMetaFileVNode(hfsmp->hfs_attribute_vp);

        ReleaseMetaFileVNode(hfsmp->hfs_catalog_vp);
        ReleaseMetaFileVNode(hfsmp->hfs_extents_vp);

        /*
         * Setting these pointers to NULL so that any references
         * past this point will fail, and tell us the point of failure.
         * Also, facilitates a check in hfs_update for a null catalog
         * vp
         */
        hfsmp->hfs_allocation_vp = NULL;
        hfsmp->hfs_attribute_vp = NULL;
        hfsmp->hfs_catalog_vp = NULL;
        hfsmp->hfs_extents_vp = NULL;
        hfsmp->hfs_startup_vp = NULL;

        return (0);
}


/*
 * Test if fork has overflow extents.
 */
__private_extern__
int
overflow_extents(struct filefork *fp)
{
        u_long 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 (FTOV(fp) == NULL || VTOVCB(FTOV(fp))->vcbSigWord == kHFSPlusSigWord) {
                if (fp->ff_extents[7].blockCount == 0)
                        return (0);

                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;  
        } else {
                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);
}


/*
 * Lock HFS system file(s).
 */
__private_extern__
int
hfs_systemfile_lock(struct hfsmount *hfsmp, int flags, enum hfslocktype locktype)
{
        /*
         * Locking order is Catalog file, Attributes file, Startup file, Bitmap file, Extents file
         */
        if (flags & SFL_CATALOG) {

#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);
                /*
                 * 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 &&
                    overflow_extents(VTOF(hfsmp->hfs_catalog_vp))) {
                        flags |= SFL_EXTENTS;
                }
        }
        if (flags & SFL_ATTRIBUTE) {

#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 */

                if (hfsmp->hfs_attribute_cp) {
                        (void) hfs_lock(hfsmp->hfs_attribute_cp, locktype);
                        /*
                         * 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 &&
                            overflow_extents(VTOF(hfsmp->hfs_attribute_vp))) {
                                flags |= SFL_EXTENTS;
                        }
                } else {
                        flags &= ~SFL_ATTRIBUTE;
                }
        }
        if (flags & SFL_STARTUP) {
#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);
                /*
                 * 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 &&
                    overflow_extents(VTOF(hfsmp->hfs_startup_vp))) {
                        flags |= SFL_EXTENTS;
                }
        }
        /* 
         * To prevent locks being taken in the wrong order, the extent lock
         * gets a bitmap lock as well.
         */
        if (flags & (SFL_BITMAP | SFL_EXTENTS)) {
                /*
                 * Since the only bitmap operations are clearing and
                 * setting bits we always need exclusive access. And
                 * when we have a journal, we can "hide" behind that
                 * lock since we can only change the bitmap from
                 * within a transaction.
                 */
                if (hfsmp->jnl || (hfsmp->hfs_allocation_cp == NULL)) {
                        flags &= ~SFL_BITMAP;
                } else {
                        (void) hfs_lock(hfsmp->hfs_allocation_cp, HFS_EXCLUSIVE_LOCK);
                        /* 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;
                }
        }
        if (flags & SFL_EXTENTS) {
                /*
                 * Since the extents btree lock is recursive we always
                 * need exclusive access.
                 */
                (void) hfs_lock(hfsmp->hfs_extents_cp, HFS_EXCLUSIVE_LOCK);
        }
        return (flags);
}

/*
 * unlock HFS system file(s).
 */
__private_extern__
void
hfs_systemfile_unlock(struct hfsmount *hfsmp, int flags)
{
        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) {
                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) {
                hfs_unlock(hfsmp->hfs_allocation_cp);
        }
        if (flags & SFL_EXTENTS) {
                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);
        }
}


/*
 * RequireFileLock
 *
 * Check to see if a vnode is locked in the current context
 * This is to be used for debugging purposes only!!
 */
#if HFS_DIAGNOSTIC
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 == (void *)current_thread();
        
        if (!locked && !shareable) {
                switch (VTOC(vp)->c_fileid) {
                case kHFSExtentsFileID:
                        panic("extents btree not locked! v: 0x%08X\n #\n", (u_int)vp);
                        break;
                case kHFSCatalogFileID:
                        panic("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("allocation file not locked! v: 0x%08X\n #\n", (u_int)vp);
                        break;
                case kHFSStartupFileID:
                        panic("startup file not locked! v: 0x%08X\n #\n", (u_int)vp);
                case kHFSAttributesFileID:
                        panic("attributes btree not locked! v: 0x%08X\n #\n", (u_int)vp);
                        break;
                }
        }
}
#endif


/*
 * 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);
        }
}


unsigned long BestBlockSizeFit(unsigned long allocationBlockSize,
                               unsigned long blockSizeLimit,
                               unsigned long 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;
    unsigned long 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;
}


__private_extern__
u_long
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, 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.
 */
__private_extern__
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;
        int started_tr = 0;
        int lockflags;
        int result;
        int orphanedlinks = 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;

        MALLOC(iterator, struct BTreeIterator *, sizeof(*iterator), M_TEMP, M_WAITOK);
        bzero(iterator, 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) == 0) {
                        struct filefork dfork;
                        struct filefork rfork;
                        struct cnode cnode;

                        bzero(&dfork, sizeof(dfork));
                        bzero(&rfork, sizeof(rfork));
                        bzero(&cnode, sizeof(cnode));
                        
                        /* Delete any attributes, ignore errors */
                        (void) hfs_removeallattr(hfsmp, filerec.fileID);
                        
                        if (hfs_start_transaction(hfsmp) != 0) {
                            printf("hfs_remove_orphans: failed to start transaction\n");
                            goto exit;
                        }
                        started_tr = 1;
                
                        /*
                         * 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 && overflow_extents(&dfork)) {
                                                fsize -= HFS_BIGFILE_SIZE;
                                        } else {
                                                fsize = 0;
                                        }

                                        if (TruncateFileC(vcb, (FCB*)&dfork, fsize, false) != 0) {
                                                printf("error truncting 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 && started_tr) {
                                                /* 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 = 0;
                                                        break;
                                                }
                                                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, false) != 0) {
                                        printf("error truncting rsrc fork!\n");
                                        break;
                                }
                        }

                        /* 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;
                        }
                        ++orphanedlinks;

                        /* Update parent and volume counts */   
                        hfsmp->hfs_private_attr[FILE_HARDLINKS].ca_entries--;
                        if (cnode.c_attr.ca_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 (cnode.c_attr.ca_mode & S_IFDIR) {
                                hfs_volupdate(hfsmp, VOL_RMDIR, 0);
                        }
                        else{
                                hfs_volupdate(hfsmp, VOL_RMFILE, 0);
                        }

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

                } /* end if */
        } /* end for */
        if (orphanedlinks > 0)
                printf("HFS: Removed %d orphaned unlinked files or directories \n", orphanedlinks);
exit:
        if (catlock) {
                hfs_systemfile_unlock(hfsmp, lockflags);
        }
        if (catreserve) {
                cat_postflight(hfsmp, &cookie, p);
        }
        if (started_tr) {
                hfs_end_transaction(hfsmp);
        }

        FREE(iterator, M_TEMP);
        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;
        
        DBG_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;
                }
        }

        DBG_ASSERT(logBlockSize > 0);
        
        return logBlockSize;    
}

__private_extern__
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 automically
         * on aligned addresses.
         */
        freeblks = hfsmp->freeBlocks;
        rsrvblks = hfsmp->reserveBlocks;
        loanblks = hfsmp->loanedBlocks;
        if (wantreserve) {
                if (freeblks > rsrvblks)
                        freeblks -= rsrvblks;
                else
                        freeblks = 0;
        }
        if (freeblks > loanblks)
                freeblks -= loanblks;
        else
                freeblks = 0;

#ifdef HFS_SPARSE_DEV
        /* 
         * When the underlying device is sparse, check the
         * available space on the backing store volume.
         */
        if ((hfsmp->hfs_flags & HFS_HAS_SPARSE_DEVICE) && hfsmp->hfs_backingfs_rootvp) {
                struct vfsstatfs *vfsp;  /* 272 bytes */
                u_int64_t vfreeblks;
                u_int32_t loanedblks;
                struct mount * backingfs_mp;
                struct timeval now;

                backingfs_mp = vnode_mount(hfsmp->hfs_backingfs_rootvp);

                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))) {
                        HFS_MOUNT_LOCK(hfsmp, TRUE);
                        vfreeblks = vfsp->f_bavail;
                        /* Normalize block count if needed. */
                        if (vfsp->f_bsize != hfsmp->blockSize) {
                                vfreeblks = ((u_int64_t)vfreeblks * (u_int64_t)(vfsp->f_bsize)) / hfsmp->blockSize;
                        }
                        if (vfreeblks > (unsigned int)hfsmp->hfs_sparsebandblks)
                                vfreeblks -= hfsmp->hfs_sparsebandblks;
                        else
                                vfreeblks = 0;
                        
                        /* Take into account any delayed allocations. */
                        loanedblks = 2 * hfsmp->loanedBlocks;
                        if (vfreeblks > loanedblks)
                                vfreeblks -= loanedblks;
                        else
                                vfreeblks = 0;

                        freeblks = MIN(vfreeblks, freeblks);
                        HFS_MOUNT_UNLOCK(hfsmp, TRUE);
                }
        }
#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;

        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.
 */
__private_extern__
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 */
                        MALLOC_ZONE(hint, directoryhint_t *, sizeof(directoryhint_t), M_HFSDIRHINT, M_WAITOK);
                        ++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.
 */
__private_extern__
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);
        }
        FREE_ZONE(relhint, sizeof(directoryhint_t), M_HFSDIRHINT);
}

/*
 * Release directory hints for given directory
 *
 * Requires an exclusive lock on directory cnode.
 */
__private_extern__
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);
                FREE_ZONE(hint, sizeof(directoryhint_t), M_HFSDIRHINT);
                --dcp->c_dirhintcnt;
        }
}

/*
 * Insert a detached directory hint back into the list of dirhints.
 *
 * Requires an exclusive lock on directory cnode.
 */
__private_extern__
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.
 */
__private_extern__
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;
        MALLOC(ustr1, u_int16_t *, maxbytes << 1, M_TEMP, M_WAITOK);
        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:
        FREE(ustr1, M_TEMP);
        return (cmp);
}


__private_extern__
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;
        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;
        
        devvp = hfsmp->hfs_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;
                                
        retval = (int)buf_meta_bread(devvp,
                                                (daddr64_t)((embeddedOffset/blksize) + 
                                                (SWAP_BE32(vhp->journalInfoBlock)*sectors_per_fsblock)),
                                                SWAP_BE32(vhp->blockSize), cred, &jinfo_bp);
        if (retval)
                return retval;

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

        if (jib_flags & kJIJournalInFSMask) {
                hfsmp->jvp = hfsmp->hfs_devvp;
        } else {
                printf("hfs: journal not stored in fs! don't know what to do.\n");
                buf_brelse(jinfo_bp);
                return EINVAL;
        }

        // 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) {
              printf("hfs: early journal init: volume on %s is read-only and journal is dirty.  Can not mount volume.\n",
                     vnode_name(devvp));
            }

            return retval;
        }

        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);

                // 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);

                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));
                        }
                        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) {
                                buf_brelse(bp);
                                printf("hfs: failed to reload the mdb after opening the journal (retval %d)!\n",
                                           retval);
                                return retval;
                        }
                        bcopy((char *)buf_dataptr(bp) + HFS_PRI_OFFSET(hfsmp->hfs_physical_block_size), mdbp, 512);
                        buf_brelse(bp);
                        bp = NULL;
                }
        }


        //printf("journal @ 0x%x\n", hfsmp->jnl);
        
        // 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);
                return EINVAL;
        }

        return 0;
}


//
// 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_long            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",
                           jib_fork.cf_extents[0].startBlock);
                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;
        retval = (int)buf_meta_bread(devvp,
                                                (daddr64_t)(vcb->hfsPlusIOPosOffset / hfsmp->hfs_logical_block_size + 
                                                (SWAP_BE32(vhp->journalInfoBlock)*sectors_per_fsblock)),
                                                SWAP_BE32(vhp->blockSize), NOCRED, &jinfo_bp);
        if (retval) {
                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",
                           jfork.cf_extents[0].startBlock);
                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_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;
        } else {
                printf("hfs: journal not stored in fs! don't know what to do.\n");
                buf_brelse(jinfo_bp);
                return EINVAL;
        }

        // 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 + (off_t)vcb->hfsPlusIOPosOffset,
                                      jib_size,
                                      devvp,
                                      hfsmp->hfs_logical_block_size);

            hfsmp->jnl = NULL;

            buf_brelse(jinfo_bp);

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

            return retval;
        }

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

                // 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 + (off_t)vcb->hfsPlusIOPosOffset,
                //         jib_size, SWAP_BE32(vhp->blockSize));
                                
                hfsmp->jnl = journal_open(hfsmp->jvp,
                                                                  jib_offset + (off_t)vcb->hfsPlusIOPosOffset,
                                                                  jib_size,
                                                                  devvp,
                                                                  hfsmp->hfs_logical_block_size,
                                                                  arg_flags,
                                                                  arg_tbufsz,
                                                                  hfs_sync_metadata, hfsmp->hfs_mp);
        }
                        

        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;

        //printf("journal @ 0x%x\n", hfsmp->jnl);
        
        // 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 OVERFLOW_DEFAULT_SIZE (4*1024*1024)
#define OVERFLOW_MAXIMUM_SIZE (128*1024*1024)
#define JOURNAL_DEFAULT_SIZE  (8*1024*1024)
#define JOURNAL_MAXIMUM_SIZE  (512*1024*1024)
#define HOTBAND_MINIMUM_SIZE  (10*1024*1024)
#define HOTBAND_MAXIMUM_SIZE  (512*1024*1024)

static void
hfs_metadatazone_init(struct hfsmount *hfsmp)
{
        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;

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

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

        /*
         * Start with allocation bitmap (a fixed size).
         */
        zonesize = roundup(vcb->totalBlocks / 8, vcb->vcbVBMIOSize);

        /*
         * Overflow Extents file gets 4 MB per 100 GB.
         */
        items = fs_size / ((u_int64_t)100 * GIGABYTE);
        filesize = (u_int64_t)(items + 1) * OVERFLOW_DEFAULT_SIZE;
        if (filesize > OVERFLOW_MAXIMUM_SIZE)
                filesize = OVERFLOW_MAXIMUM_SIZE;
        zonesize += filesize;
        hfsmp->hfs_overflow_maxblks = filesize / vcb->blockSize;

        /*
         * Plan for at least 8 MB of journal for each
         * 100 GB of disk space (up to a 512 MB).
         */
        items = fs_size / ((u_int64_t)100 * GIGABYTE);
        filesize = (u_int64_t)(items + 1) * JOURNAL_DEFAULT_SIZE;
        if (filesize > JOURNAL_MAXIMUM_SIZE)
                filesize = JOURNAL_MAXIMUM_SIZE;
        zonesize += filesize;

        /*
         * Catalog file gets 10 MB per 1 GB.
         *
         * How about considering the current catalog size (used nodes * node size)
         * and the current file data size to help estimate the required
         * catalog size.
         */
        filesize = MIN((fs_size / 1024) * 10, GIGABYTE);
        hfsmp->hfs_catalog_maxblks = filesize / vcb->blockSize;
        zonesize += filesize;

        /*
         * 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.
         */
        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);
        temp = zonesize - temp;  /* temp has extra space */
        filesize += temp / 3;
        hfsmp->hfs_catalog_maxblks += (temp - (temp / 3)) / vcb->blockSize;

        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. */
        hfsmp->hfs_hotfile_start = blk - (filesize / vcb->blockSize);
        hfsmp->hfs_hotfile_end = hfsmp->hfs_metazone_end;
        hfsmp->hfs_hotfile_freeblks = hfs_hotfile_freeblocks(hfsmp);
#if 0
        printf("HFS: metadata zone is %d to %d\n", hfsmp->hfs_metazone_start, hfsmp->hfs_metazone_end);
        printf("HFS: hot file band is %d to %d\n", hfsmp->hfs_hotfile_start, hfsmp->hfs_hotfile_end);
        printf("HFS: hot file band free blocks = %d\n", 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;

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

        /* Minus Extents overflow file reserve. */
        freeblocks -=
                hfsmp->hfs_overflow_maxblks - VTOF(hfsmp->hfs_extents_vp)->ff_blocks;
        /* Minus catalog file reserve. */
        freeblocks -=
                hfsmp->hfs_catalog_maxblks - VTOF(hfsmp->hfs_catalog_vp)->ff_blocks;
        if (freeblocks < 0)
                freeblocks = 0;

        return MIN(freeblocks, hfsmp->hfs_hotfile_maxblks);
}

/*
 * Determine if a file is a "virtual" metadata file.
 * This includes journal and quota files.
 */
__private_extern__
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);
}



//
// Fire off a timed callback to sync the disk if the
// volume is on ejectable media.
//
 __private_extern__
void
hfs_sync_ejectable(struct hfsmount *hfsmp)
{
        if (hfsmp->hfs_syncer)  {
                uint32_t secs, usecs;
                uint64_t now;

                clock_get_calendar_microtime(&secs, &usecs);
                now = ((uint64_t)secs * 1000000) + usecs;

                if (hfsmp->hfs_sync_scheduled == 0) {
                        uint64_t deadline;

                        hfsmp->hfs_last_sync_request_time = now;

                        clock_interval_to_deadline(HFS_META_DELAY, HFS_MILLISEC_SCALE, &deadline);

                        /*
                         * Increment hfs_sync_scheduled on the assumption that we're the
                         * first thread to schedule the timer.  If some other thread beat
                         * us, then we'll decrement it.  If we *were* the first to
                         * schedule the timer, then we need to keep track that the
                         * callback is waiting to complete.
                         */
                        OSIncrementAtomic((volatile SInt32 *)&hfsmp->hfs_sync_scheduled);
                        if (thread_call_enter_delayed(hfsmp->hfs_syncer, deadline))
                                OSDecrementAtomic((volatile SInt32 *)&hfsmp->hfs_sync_scheduled);
                        else
                                OSIncrementAtomic((volatile SInt32 *)&hfsmp->hfs_sync_incomplete);
                }               
        }
}


__private_extern__
int
hfs_start_transaction(struct hfsmount *hfsmp)
{
        int ret, unlock_on_err=0;
        void * 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 */

    if (hfsmp->jnl == NULL || journal_owner(hfsmp->jnl) != thread) {
        lck_rw_lock_shared(&hfsmp->hfs_global_lock);
        OSAddAtomic(1, (SInt32 *)&hfsmp->hfs_active_threads);
        unlock_on_err = 1;
    }

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

    if (hfsmp->jnl) {
        ret = journal_start_transaction(hfsmp->jnl);
        if (ret == 0) {
            OSAddAtomic(1, (SInt32 *)&hfsmp->hfs_global_lock_nesting);
        }
    } else {
        ret = 0;
    }

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

    return ret;
}

__private_extern__
int
hfs_end_transaction(struct hfsmount *hfsmp)
{
    int need_unlock=0, ret;

    if (    hfsmp->jnl == NULL
        || (   journal_owner(hfsmp->jnl) == current_thread()
            && (OSAddAtomic(-1, (SInt32 *)&hfsmp->hfs_global_lock_nesting) == 1)) ) {

            need_unlock = 1;
    } 

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

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

    return ret;
}