]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/hfs/hfscommon/Misc/VolumeAllocation.c
xnu-1504.9.17.tar.gz
[apple/xnu.git] / bsd / hfs / hfscommon / Misc / VolumeAllocation.c
index e8006d1074dec873facb9737c46a85fc6cf6acf6..3d8255a9e18f95b44fa2f329e75f4a2917388760 100644 (file)
@@ -1,23 +1,29 @@
 /*
- * Copyright (c) 2000-2001 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2008 Apple Inc. All rights reserved.
  *
- * @APPLE_LICENSE_HEADER_START@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License").  You may not use this file except in compliance with the
- * License.  Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
+ * 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.
  * 
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * 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 OR NON-INFRINGEMENT.  Please see the
- * License for the specific language governing rights and limitations
- * under the License.
+ * 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_LICENSE_HEADER_END@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 /*
        File:           VolumeAllocation.c
@@ -40,6 +46,7 @@ Public routines:
        BlockDeallocate
                                        Deallocate a contiguous run of allocation blocks.
 
+       invalidate_free_extent_cache    Invalidate free extent cache for a given volume.
 
 Internal routines:
        BlockMarkFree
@@ -80,6 +87,7 @@ Internal routines:
 #include <sys/types.h>
 #include <sys/buf.h>
 #include <sys/systm.h>
+#include <sys/disk.h>
 
 #include "../../hfs.h"
 #include "../../hfs_dbg.h"
@@ -104,56 +112,51 @@ enum {
 
 static OSErr ReadBitmapBlock(
        ExtendedVCB             *vcb,
-       UInt32                  bit,
-       UInt32                  **buffer,
-       UInt32                  *blockRef);
+       u_int32_t               bit,
+       u_int32_t               **buffer,
+       uintptr_t               *blockRef);
 
 static OSErr ReleaseBitmapBlock(
        ExtendedVCB             *vcb,
-       UInt32                  blockRef,
+       uintptr_t               blockRef,
        Boolean                 dirty);
 
 static OSErr BlockAllocateAny(
        ExtendedVCB             *vcb,
-       UInt32                  startingBlock,
-       UInt32                  endingBlock,
-       UInt32                  maxBlocks,
-       UInt32                  *actualStartBlock,
-       UInt32                  *actualNumBlocks);
+       u_int32_t               startingBlock,
+       u_int32_t               endingBlock,
+       u_int32_t               maxBlocks,
+       Boolean                 useMetaZone,
+       u_int32_t               *actualStartBlock,
+       u_int32_t               *actualNumBlocks);
 
 static OSErr BlockAllocateContig(
        ExtendedVCB             *vcb,
-       UInt32                  startingBlock,
-       UInt32                  minBlocks,
-       UInt32                  maxBlocks,
-       UInt32                  *actualStartBlock,
-       UInt32                  *actualNumBlocks);
+       u_int32_t               startingBlock,
+       u_int32_t               minBlocks,
+       u_int32_t               maxBlocks,
+       Boolean                 useMetaZone,
+       u_int32_t               *actualStartBlock,
+       u_int32_t               *actualNumBlocks);
 
 static OSErr BlockFindContiguous(
        ExtendedVCB             *vcb,
-       UInt32                  startingBlock,
-       UInt32                  endingBlock,
-       UInt32                  minBlocks,
-       UInt32                  maxBlocks,
-       UInt32                  *actualStartBlock,
-       UInt32                  *actualNumBlocks);
-
-static OSErr BlockMarkAllocated(
-       ExtendedVCB             *vcb,
-       UInt32                  startingBlock,
-       UInt32                  numBlocks);
-
-static OSErr BlockMarkFree(
-       ExtendedVCB             *vcb,
-       UInt32                  startingBlock,
-       UInt32                  numBlocks);
+       u_int32_t               startingBlock,
+       u_int32_t               endingBlock,
+       u_int32_t               minBlocks,
+       u_int32_t               maxBlocks,
+       Boolean                 useMetaZone,
+       u_int32_t               *actualStartBlock,
+       u_int32_t               *actualNumBlocks);
 
 static OSErr BlockAllocateKnown(
        ExtendedVCB             *vcb,
-       UInt32                  maxBlocks,
-       UInt32                  *actualStartBlock,
-       UInt32                  *actualNumBlocks);
+       u_int32_t               maxBlocks,
+       u_int32_t               *actualStartBlock,
+       u_int32_t               *actualNumBlocks);
 
+static int free_extent_cache_active(
+       ExtendedVCB             *vcb);
 
 /*
 ;________________________________________________________________________________
@@ -172,19 +175,17 @@ static OSErr BlockAllocateKnown(
 ;                         the volume's allocation block pointer will be used as a starting
 ;                         point.
 ;
-;                         All requests will be rounded up to the next highest clump size, as
-;                         indicated in the file's FCB.
-;
 ; Input Arguments:
 ;       vcb                     - Pointer to ExtendedVCB for the volume to allocate space on
 ;       fcb                     - Pointer to FCB for the file for which storage is being allocated
 ;       startingBlock   - Preferred starting allocation block, 0 = no preference
 ;       forceContiguous - Force contiguous flag - if bit 0 set (NE), allocation is contiguous
 ;                                         or an error is returned
-;       bytesRequested  - Number of bytes requested.   If the allocation is non-contiguous,
+;       useMetaZone  - 
+;       minBlocks       - Number of blocks requested.  If the allocation is non-contiguous,
 ;                                         less than this may actually be allocated
-;       bytesMaximum    - The maximum number of bytes to allocate.  If there is additional free
-;                                         space after bytesRequested, then up to bytesMaximum bytes should really
+;       maxBlocks       - The maximum number of blocks to allocate.  If there is additional free
+;                                         space after bytesRequested, then up to maxBlocks bytes should really
 ;                                         be allocated.  (Used by ExtendFileC to round up allocations to a multiple
 ;                                         of the file's clump size.)
 ;
@@ -197,65 +198,146 @@ static OSErr BlockAllocateKnown(
 ;       The volume bitmap is read and updated; the volume bitmap cache may be changed.
 ;________________________________________________________________________________
 */
+static void
+sanity_check_free_ext(__unused ExtendedVCB *vcb, __unused int check_allocated)
+{
+#if DEBUG
+       u_int32_t i, j;
+
+       for(i=0; i < vcb->vcbFreeExtCnt; i++) {
+               u_int32_t start, nblocks;
+
+               start   = vcb->vcbFreeExt[i].startBlock;
+               nblocks = vcb->vcbFreeExt[i].blockCount;
+
+
+               if (nblocks == 0) {
+                       panic("hfs: %p: slot %d in the free extent array had a zero count (%d)\n", vcb, i, start);
+               }
+
+               if (check_allocated && hfs_isallocated(vcb, start, nblocks)) {
+                       panic("hfs: %p: slot %d in the free extent array is bad (%d / %d)\n",
+                             vcb, i, start, nblocks);
+               }
+
+               for(j=i+1; j < vcb->vcbFreeExtCnt; j++) {
+                       if (start == vcb->vcbFreeExt[j].startBlock) {
+                               panic("hfs: %p: slot %d/%d are dups?! (%d / %d ; %d / %d)\n",
+                                     vcb, i, j, start, nblocks, vcb->vcbFreeExt[i].startBlock,
+                                     vcb->vcbFreeExt[i].blockCount);
+                       }
+               }
+       }
+#endif
+}
+
 
+__private_extern__
 OSErr BlockAllocate (
        ExtendedVCB             *vcb,                           /* which volume to allocate space on */
-       UInt32                  startingBlock,          /* preferred starting block, or 0 for no preference */
-       SInt64                  bytesRequested,         /* desired number of BYTES to allocate */
-       SInt64                  bytesMaximum,           /* maximum number of bytes to allocate */
-       Boolean                 forceContiguous,        /* non-zero to force contiguous allocation and to force */
-                                                                               /* bytesRequested bytes to actually be allocated */
-       UInt32                  *actualStartBlock,      /* actual first block of allocation */
-       UInt32                  *actualNumBlocks)       /* number of blocks actually allocated; if forceContiguous */
-                                                                               /* was zero, then this may represent fewer than bytesRequested */
-                                                                               /* bytes */
+       u_int32_t               startingBlock,          /* preferred starting block, or 0 for no preference */
+       u_int32_t               minBlocks,              /* desired number of blocks to allocate */
+       u_int32_t               maxBlocks,              /* maximum number of blocks to allocate */
+       u_int32_t               flags,                  /* option flags */
+       u_int32_t               *actualStartBlock,      /* actual first block of allocation */
+       u_int32_t               *actualNumBlocks)       /* number of blocks actually allocated; if forceContiguous */
+                                                       /* was zero, then this may represent fewer than minBlocks */
 {
+       u_int32_t  freeBlocks;
        OSErr                   err;
-       UInt32                  minBlocks;                                      //      minimum number of allocation blocks requested
-       UInt32                  maxBlocks;                                      //      number of allocation blocks requested, rounded to clump size
        Boolean                 updateAllocPtr = false;         //      true if nextAllocation needs to be updated
+       Boolean useMetaZone;
+       Boolean forceContiguous;
+
+       if (flags & HFS_ALLOC_FORCECONTIG) {
+               forceContiguous = true;
+       } else {
+               forceContiguous = false;
+       }
+
+       if (flags & HFS_ALLOC_METAZONE) {
+               useMetaZone = true;
+       } else {
+               useMetaZone = false;
+       }
 
        //
        //      Initialize outputs in case we get an error
        //
        *actualStartBlock = 0;
        *actualNumBlocks = 0;
+       freeBlocks = hfs_freeblks(VCBTOHFS(vcb), 0);
        
-       //
-       //      Compute the number of allocation blocks requested, and maximum
-       //
-       minBlocks = FileBytesToBlocks(bytesRequested, vcb->blockSize);
-       maxBlocks = FileBytesToBlocks(bytesMaximum, vcb->blockSize);
-       
-       //
-       //      If the disk is already full, don't bother.
-       //
-       if (vcb->freeBlocks == 0) {
-               err = dskFulErr;
-               goto Exit;
-       }
-       if (forceContiguous && vcb->freeBlocks < minBlocks) {
-               err = dskFulErr;
-               goto Exit;
+       /* Skip free block check if blocks are being allocated for relocating 
+        * data during truncating a volume.
+        * 
+        * During hfs_truncatefs(), the volume free block count is updated 
+        * before relocating data to reflect the total number of free blocks 
+        * that will exist on the volume after resize is successful.  This 
+        * means that we have reserved allocation blocks required for relocating 
+        * the data and hence there is no need to check the free blocks.
+        * It will also prevent resize failure when the number of blocks in 
+        * an extent being relocated is more than the free blocks that will 
+        * exist after the volume is resized.
+        */
+       if ((flags & HFS_ALLOC_SKIPFREEBLKS) == 0) {
+               //      If the disk is already full, don't bother.
+               if (freeBlocks == 0) {
+                       err = dskFulErr;
+                       goto Exit;
+               }
+               if (forceContiguous && freeBlocks < minBlocks) {
+                       err = dskFulErr;
+                       goto Exit;
+               }
+
+               /*
+                * Clip if necessary so we don't over-subscribe the free blocks.
+                */
+               if (minBlocks > freeBlocks) {
+                       minBlocks = freeBlocks;
+               }
+               if (maxBlocks > freeBlocks) {
+                       maxBlocks = freeBlocks;
+               }
        }
-       
+
        //
        //      If caller didn't specify a starting block number, then use the volume's
        //      next block to allocate from.
        //
        if (startingBlock == 0) {
-               VCB_LOCK(vcb);
-               startingBlock = vcb->nextAllocation;
-               VCB_UNLOCK(vcb);
+               HFS_MOUNT_LOCK(vcb, TRUE);
+               if (vcb->hfs_flags & HFS_HAS_SPARSE_DEVICE) {
+                       startingBlock = vcb->sparseAllocation;
+               } else {
+                       startingBlock = vcb->nextAllocation;
+               }
+               HFS_MOUNT_UNLOCK(vcb, TRUE);
                updateAllocPtr = true;
        }
+       if (startingBlock >= vcb->allocLimit) {
+               startingBlock = 0; /* overflow so start at beginning */
+       }
 
        //
        //      If the request must be contiguous, then find a sequence of free blocks
        //      that is long enough.  Otherwise, find the first free block.
        //
        if (forceContiguous) {
-               err = BlockAllocateContig(vcb, startingBlock, minBlocks, maxBlocks, actualStartBlock, actualNumBlocks);
+               err = BlockAllocateContig(vcb, startingBlock, minBlocks, maxBlocks,
+                                         useMetaZone, actualStartBlock, actualNumBlocks);
+               /*
+                * If we allocated from a new position then
+                * also update the roving allocator.
+                */
+               if ((err == noErr) &&
+                   (*actualStartBlock > startingBlock) &&
+                   ((*actualStartBlock < VCBTOHFS(vcb)->hfs_metazone_start) ||
+                    (*actualStartBlock > VCBTOHFS(vcb)->hfs_metazone_end))) {
+
+                       updateAllocPtr = true;
+               }
        } else {
                /*
                 * Scan the bitmap once, gather the N largest free extents, then
@@ -266,12 +348,24 @@ OSErr BlockAllocate (
                 */
                err = BlockAllocateKnown(vcb, maxBlocks, actualStartBlock, actualNumBlocks);
                if (err == dskFulErr)
-                       err = BlockAllocateAny(vcb, startingBlock, vcb->totalBlocks, maxBlocks, actualStartBlock, actualNumBlocks);
+                       err = BlockAllocateAny(vcb, startingBlock, vcb->allocLimit,
+                                              maxBlocks, useMetaZone, actualStartBlock,
+                                              actualNumBlocks);
                if (err == dskFulErr)
-                       err = BlockAllocateAny(vcb, 0, startingBlock, maxBlocks, actualStartBlock, actualNumBlocks);
+                       err = BlockAllocateAny(vcb, 1, startingBlock, maxBlocks,
+                                              useMetaZone, actualStartBlock,
+                                              actualNumBlocks);
        }
 
-       if (err == noErr) {
+Exit:
+       // if we actually allocated something then go update the
+       // various bits of state that we maintain regardless of
+       // whether there was an error (i.e. partial allocations
+       // still need to update things like the free block count).
+       //
+       if (*actualNumBlocks != 0) {
+               int i,j;
+
                //
                //      If we used the volume's roving allocation pointer, then we need to update it.
                //      Adding in the length of the current allocation might reduce the next allocate
@@ -280,22 +374,61 @@ OSErr BlockAllocate (
                //      the file is closed or its EOF changed.  Leaving the allocation pointer at the
                //      start of the last allocation will avoid unnecessary fragmentation in this case.
                //
-               VCB_LOCK(vcb);
+               HFS_MOUNT_LOCK(vcb, TRUE);
 
-               if (updateAllocPtr)
-                       vcb->nextAllocation = *actualStartBlock;
+               if (vcb->vcbFreeExtCnt == 0 && vcb->hfs_freed_block_count == 0) {
+                       vcb->sparseAllocation = *actualStartBlock;
+               }
+               if (*actualNumBlocks < vcb->hfs_freed_block_count) {
+                       vcb->hfs_freed_block_count -= *actualNumBlocks;
+               } else {
+                       vcb->hfs_freed_block_count = 0;
+               }
                
-               //
-               //      Update the number of free blocks on the volume
-               //
-               vcb->freeBlocks -= *actualNumBlocks;
-               VCB_UNLOCK(vcb);
+               if (updateAllocPtr &&
+                   ((*actualStartBlock < VCBTOHFS(vcb)->hfs_metazone_start) ||
+                    (*actualStartBlock > VCBTOHFS(vcb)->hfs_metazone_end))) {
+                       HFS_UPDATE_NEXT_ALLOCATION(vcb, *actualStartBlock);
+               }
+
+               for(i=0; i < (int)vcb->vcbFreeExtCnt; i++) {
+                       u_int32_t start, end;
+
+                       start = vcb->vcbFreeExt[i].startBlock;
+                       end   = start + vcb->vcbFreeExt[i].blockCount;
+
+                       if (   (*actualStartBlock >= start && *actualStartBlock < end)
+                           || ((*actualStartBlock + *actualNumBlocks) > start && *actualStartBlock < start)) {
+
+                               for(j=i; j < (int)vcb->vcbFreeExtCnt-1; j++) {
+                                       vcb->vcbFreeExt[j] = vcb->vcbFreeExt[j+1];
+                               }
+
+                               vcb->vcbFreeExtCnt--;
+                               i--;   // so we'll check the guy we just copied down...
+                               
+                               // keep looping because we may have invalidated more
+                               // than one entry in the array
+                       }
+               }
 
+               /* 
+                * Update the number of free blocks on the volume 
+                *
+                * Skip updating the free blocks count if the block are 
+                * being allocated to relocate data as part of hfs_truncatefs()
+                */
+               if ((flags & HFS_ALLOC_SKIPFREEBLKS) == 0) {
+                       vcb->freeBlocks -= *actualNumBlocks;
+               }
                MarkVCBDirty(vcb);
+               HFS_MOUNT_UNLOCK(vcb, TRUE);
+
+               sanity_check_free_ext(vcb, 1);
+
+               hfs_generate_volume_notifications(VCBTOHFS(vcb));
        }
        
-Exit:
-
        return err;
 }
 
@@ -320,12 +453,15 @@ Exit:
 ;________________________________________________________________________________
 */
 
+__private_extern__
 OSErr BlockDeallocate (
        ExtendedVCB             *vcb,                   //      Which volume to deallocate space on
-       UInt32                  firstBlock,             //      First block in range to deallocate
-       UInt32                  numBlocks)              //      Number of contiguous blocks to deallocate
+       u_int32_t               firstBlock,             //      First block in range to deallocate
+       u_int32_t               numBlocks,              //      Number of contiguous blocks to deallocate
+       u_int32_t               flags)
 {
        OSErr                   err;
+       u_int32_t               tempWord;
        
        //
        //      If no blocks to deallocate, then exit early
@@ -345,44 +481,172 @@ OSErr BlockDeallocate (
        //
        //      Update the volume's free block count, and mark the VCB as dirty.
        //
-       VCB_LOCK(vcb);
-       vcb->freeBlocks += numBlocks;
-       VCB_UNLOCK(vcb);
+       HFS_MOUNT_LOCK(vcb, TRUE);
+       
+       /* 
+        * Do not update the free block count.  This flags is specified 
+        * when a volume is being truncated.  
+        */
+       if ((flags & HFS_ALLOC_SKIPFREEBLKS) == 0) {
+               vcb->freeBlocks += numBlocks;
+       }
+
+       vcb->hfs_freed_block_count += numBlocks;
+       if (firstBlock < vcb->sparseAllocation) {
+               vcb->sparseAllocation = firstBlock;
+       }
+
+       if (vcb->nextAllocation == (firstBlock + numBlocks)) {
+               HFS_UPDATE_NEXT_ALLOCATION(vcb, (vcb->nextAllocation - numBlocks));
+       }
+
+       if (free_extent_cache_active(vcb) == 0) {
+               goto skip_cache;
+       }
+
+       tempWord = vcb->vcbFreeExtCnt;
+       //      Add this free chunk to the free extent list
+       if (vcb->hfs_flags & HFS_HAS_SPARSE_DEVICE) {
+               // Sorted by start block
+               if (tempWord == kMaxFreeExtents && vcb->vcbFreeExt[kMaxFreeExtents-1].startBlock > firstBlock)
+                       --tempWord;
+               if (tempWord < kMaxFreeExtents)
+               {
+                       //      We're going to add this extent.  Bubble any smaller extents down in the list.
+                       while (tempWord && vcb->vcbFreeExt[tempWord-1].startBlock > firstBlock)
+                       {
+                               vcb->vcbFreeExt[tempWord] = vcb->vcbFreeExt[tempWord-1];
+                               if (vcb->vcbFreeExt[tempWord].startBlock < vcb->sparseAllocation) {
+                                       vcb->sparseAllocation = vcb->vcbFreeExt[tempWord].startBlock;
+                               }
+                               --tempWord;
+                       }
+                       vcb->vcbFreeExt[tempWord].startBlock = firstBlock;
+                       vcb->vcbFreeExt[tempWord].blockCount = numBlocks;
+                       
+                       if (vcb->vcbFreeExtCnt < kMaxFreeExtents) {
+                               ++vcb->vcbFreeExtCnt;
+                       }
+               }
+       } else {
+               // Sorted by num blocks
+               if (tempWord == kMaxFreeExtents && vcb->vcbFreeExt[kMaxFreeExtents-1].blockCount < numBlocks)
+                       --tempWord;
+               if (tempWord < kMaxFreeExtents)
+               {
+                       //      We're going to add this extent.  Bubble any smaller extents down in the list.
+                       while (tempWord && vcb->vcbFreeExt[tempWord-1].blockCount < numBlocks)
+                       {
+                               vcb->vcbFreeExt[tempWord] = vcb->vcbFreeExt[tempWord-1];
+                               if (vcb->vcbFreeExt[tempWord].startBlock < vcb->sparseAllocation) {
+                                       vcb->sparseAllocation = vcb->vcbFreeExt[tempWord].startBlock;
+                               }
+                               --tempWord;
+                       }
+                       vcb->vcbFreeExt[tempWord].startBlock = firstBlock;
+                       vcb->vcbFreeExt[tempWord].blockCount = numBlocks;
+                       
+                       if (vcb->vcbFreeExtCnt < kMaxFreeExtents) {
+                               ++vcb->vcbFreeExtCnt;
+                       }
+               }
+       }
+
+skip_cache:
        MarkVCBDirty(vcb);
+       HFS_MOUNT_UNLOCK(vcb, TRUE); 
 
+       sanity_check_free_ext(vcb, 1);
+
+       hfs_generate_volume_notifications(VCBTOHFS(vcb));
 Exit:
 
        return err;
 }
 
 
-/*
-;_______________________________________________________________________
-;
-; Routine:     FileBytesToBlocks
-;
-; Function:    Divide numerator by denominator, rounding up the result if there
-;                      was a remainder.  This is frequently used for computing the number
-;                      of whole and/or partial blocks used by some count of bytes.
-;                      Actuall divides a 64 bit by a 32 bit into a 32bit result
-;              
-;                      CAREFULL!!! THIS CAN CAUSE OVERFLOW....USER BEWARE!!!
-;_______________________________________________________________________
-*/
-UInt32 FileBytesToBlocks(
-       SInt64 numerator,
-       UInt32 denominator)
+u_int8_t freebitcount[16] = {
+       4, 3, 3, 2, 3, 2, 2, 1,  /* 0 1 2 3 4 5 6 7 */
+       3, 2, 2, 1, 2, 1, 1, 0,  /* 8 9 A B C D E F */
+};
+
+__private_extern__
+u_int32_t
+MetaZoneFreeBlocks(ExtendedVCB *vcb)
 {
-       UInt32  quotient;
+       u_int32_t freeblocks;
+       u_int32_t *currCache;
+       uintptr_t blockRef;
+       u_int32_t bit;
+       u_int32_t lastbit;
+       int bytesleft;
+       int bytesperblock;
+       u_int8_t byte;
+       u_int8_t *buffer;
+
+       blockRef = 0;
+       bytesleft = freeblocks = 0;
+       buffer = NULL;
+       bit = VCBTOHFS(vcb)->hfs_metazone_start;
+       if (bit == 1)
+               bit = 0;
        
-       quotient = (UInt32)(numerator / denominator);
-       if (quotient * denominator != numerator)
-               quotient++;
-       
-       return quotient;
+       lastbit = VCBTOHFS(vcb)->hfs_metazone_end;
+       bytesperblock = vcb->vcbVBMIOSize;
+
+       /*
+        *  Count all the bits from bit to lastbit.
+        */
+       while (bit < lastbit) {
+               /*
+                *  Get next bitmap block.
+                */
+               if (bytesleft == 0) {
+                       if (blockRef) {
+                               (void) ReleaseBitmapBlock(vcb, blockRef, false);
+                               blockRef = 0;
+                       }
+                       if (ReadBitmapBlock(vcb, bit, &currCache, &blockRef) != 0) {
+                               return (0);
+                       }
+                       buffer = (u_int8_t *)currCache;
+                       bytesleft = bytesperblock;
+               }
+               byte = *buffer++;
+               freeblocks += freebitcount[byte & 0x0F];
+               freeblocks += freebitcount[(byte >> 4) & 0x0F];
+               bit += kBitsPerByte;
+               --bytesleft;
+       }
+       if (blockRef)
+               (void) ReleaseBitmapBlock(vcb, blockRef, false);
+
+       return (freeblocks);
 }
 
 
+/*
+ * Obtain the next allocation block (bit) that's
+ * outside the metadata allocation zone.
+ */
+static u_int32_t NextBitmapBlock(
+       ExtendedVCB             *vcb,
+       u_int32_t               bit)
+{
+       struct  hfsmount *hfsmp = VCBTOHFS(vcb);
+
+       if ((hfsmp->hfs_flags & HFS_METADATA_ZONE) == 0)
+               return (bit);
+       /*
+        * Skip over metadata allocation zone.
+        */
+       if ((bit >= hfsmp->hfs_metazone_start) &&
+           (bit <= hfsmp->hfs_metazone_end)) {
+               bit = hfsmp->hfs_metazone_end + 1;
+       }
+       return (bit);
+}
+
 
 /*
 ;_______________________________________________________________________
@@ -403,42 +667,42 @@ UInt32 FileBytesToBlocks(
 */
 static OSErr ReadBitmapBlock(
        ExtendedVCB             *vcb,
-       UInt32                  bit,
-       UInt32                  **buffer,
-       UInt32                  *blockRef)
+       u_int32_t               bit,
+       u_int32_t               **buffer,
+       uintptr_t               *blockRef)
 {
        OSErr                   err;
        struct buf *bp = NULL;
        struct vnode *vp = NULL;
-       UInt32 block;
-       UInt32 blockSize;
+       daddr64_t block;
+       u_int32_t blockSize;
 
        /*
-        * volume bitmap blocks are protected by the Extents B-tree lock
+        * volume bitmap blocks are protected by the allocation file lock
         */
-       REQUIRE_FILE_LOCK(vcb->extentsRefNum, false);   
+       REQUIRE_FILE_LOCK(vcb->hfs_allocation_vp, false);       
 
-       blockSize = (UInt32)vcb->vcbVBMIOSize;
-       block = bit / (blockSize * kBitsPerByte);
+       blockSize = (u_int32_t)vcb->vcbVBMIOSize;
+       block = (daddr64_t)(bit / (blockSize * kBitsPerByte));
 
        if (vcb->vcbSigWord == kHFSPlusSigWord) {
-               vp = vcb->allocationsRefNum;    /* use allocation file vnode */
+               vp = vcb->hfs_allocation_vp;    /* use allocation file vnode */
 
        } else /* hfs */ {
                vp = VCBTOHFS(vcb)->hfs_devvp;  /* use device I/O vnode */
                block += vcb->vcbVBMSt;                 /* map to physical block */
        }
 
-       err = meta_bread(vp, block, blockSize, NOCRED, &bp);
+       err = (int)buf_meta_bread(vp, block, blockSize, NOCRED, &bp);
 
        if (bp) {
                if (err) {
-                       brelse(bp);
-                       *blockRef = NULL;
+                       buf_brelse(bp);
+                       *blockRef = 0;
                        *buffer = NULL;
                } else {
-                       *blockRef = (UInt32)bp;
-                       *buffer = (UInt32 *)bp->b_data;
+                       *blockRef = (uintptr_t)bp;
+                       *buffer = (u_int32_t *)buf_dataptr(bp);
                }
        }
 
@@ -461,17 +725,29 @@ static OSErr ReadBitmapBlock(
 */
 static OSErr ReleaseBitmapBlock(
        ExtendedVCB             *vcb,
-       UInt32                  blockRef,
+       uintptr_t               blockRef,
        Boolean                 dirty)
 {
        struct buf *bp = (struct buf *)blockRef;
+       
+       if (blockRef == 0) {
+               if (dirty)
+                       panic("hfs: ReleaseBitmapBlock: missing bp");
+               return (0);
+       }
 
        if (bp) {
                if (dirty) {
-                       bp->b_flags |= B_DIRTY;
-                       bdwrite(bp);
+                       // XXXdbg
+                       struct hfsmount *hfsmp = VCBTOHFS(vcb);
+                       
+                       if (hfsmp->jnl) {
+                               journal_modify_block_end(hfsmp->jnl, bp, NULL, NULL);
+                       } else {
+                               buf_bdwrite(bp);
+                       }
                } else {
-                       brelse(bp);
+                       buf_brelse(bp);
                }
        }
 
@@ -494,6 +770,7 @@ Inputs:
        startingBlock   Preferred first block for allocation
        minBlocks               Minimum number of contiguous blocks to allocate
        maxBlocks               Maximum number of contiguous blocks to allocate
+       useMetaZone
 
 Outputs:
        actualStartBlock        First block of range allocated, or 0 if error
@@ -502,11 +779,12 @@ _______________________________________________________________________
 */
 static OSErr BlockAllocateContig(
        ExtendedVCB             *vcb,
-       UInt32                  startingBlock,
-       UInt32                  minBlocks,
-       UInt32                  maxBlocks,
-       UInt32                  *actualStartBlock,
-       UInt32                  *actualNumBlocks)
+       u_int32_t               startingBlock,
+       u_int32_t               minBlocks,
+       u_int32_t               maxBlocks,
+       Boolean                 useMetaZone,
+       u_int32_t               *actualStartBlock,
+       u_int32_t               *actualNumBlocks)
 {
        OSErr   err;
 
@@ -524,34 +802,25 @@ static OSErr BlockAllocateContig(
         * with the free extent cache, this can lead to duplicate entries
         * in the cache, causing the same blocks to be allocated twice.
         */
-       err = BlockFindContiguous(vcb, startingBlock, vcb->totalBlocks, minBlocks, maxBlocks,
-                                                                 actualStartBlock, actualNumBlocks);
+       err = BlockFindContiguous(vcb, startingBlock, vcb->allocLimit, minBlocks,
+                                 maxBlocks, useMetaZone, actualStartBlock, actualNumBlocks);
        if (err == dskFulErr && startingBlock != 0) {
                /*
                 * Constrain the endingBlock so we don't bother looking for ranges
                 * that would overlap those found in the previous call.
                 */
-               err = BlockFindContiguous(vcb, 0, startingBlock, minBlocks, maxBlocks,
-                                                                         actualStartBlock, actualNumBlocks);
+               err = BlockFindContiguous(vcb, 1, startingBlock, minBlocks, maxBlocks,
+                                         useMetaZone, actualStartBlock, actualNumBlocks);
        }
-       if (err != noErr) goto Exit;
-
        //
        //      Now mark those blocks allocated.
        //
-       err = BlockMarkAllocated(vcb, *actualStartBlock, *actualNumBlocks);
-       
-Exit:
-       if (err != noErr) {
-               *actualStartBlock = 0;
-               *actualNumBlocks = 0;
-       }
+       if (err == noErr)
+               err = BlockMarkAllocated(vcb, *actualStartBlock, *actualNumBlocks);
        
        return err;
 }
 
-extern OSErr LookupBufferMapping(caddr_t bufferAddress, struct buf **bpp, int *mappingIndexPtr);
-
 /*
 _______________________________________________________________________
 
@@ -567,6 +836,7 @@ Inputs:
        startingBlock   Preferred first block for allocation
        endingBlock             Last block to check + 1
        maxBlocks               Maximum number of contiguous blocks to allocate
+       useMetaZone
 
 Outputs:
        actualStartBlock        First block of range allocated, or 0 if error
@@ -575,23 +845,43 @@ _______________________________________________________________________
 */
 static OSErr BlockAllocateAny(
        ExtendedVCB             *vcb,
-       UInt32                  startingBlock,
-       register UInt32 endingBlock,
-       UInt32                  maxBlocks,
-       UInt32                  *actualStartBlock,
-       UInt32                  *actualNumBlocks)
+       u_int32_t               startingBlock,
+       register u_int32_t      endingBlock,
+       u_int32_t               maxBlocks,
+       Boolean                 useMetaZone,
+       u_int32_t               *actualStartBlock,
+       u_int32_t               *actualNumBlocks)
 {
        OSErr                   err;
-       register UInt32 block;                  //      current block number
-       register UInt32 currentWord;    //      Pointer to current word within bitmap block
-       register UInt32 bitMask;                //      Word with given bits already set (ready to OR in)
-       register UInt32 wordsLeft;              //      Number of words left in this bitmap block
-    UInt32                     *buffer = NULL;
-    UInt32                     *currCache = NULL;
-       UInt32  blockRef;
-       UInt32  bitsPerBlock;
-       UInt32  wordsPerBlock;
+       register u_int32_t      block;                  //      current block number
+       register u_int32_t      currentWord;    //      Pointer to current word within bitmap block
+       register u_int32_t      bitMask;                //      Word with given bits already set (ready to OR in)
+       register u_int32_t      wordsLeft;              //      Number of words left in this bitmap block
+       u_int32_t  *buffer = NULL;
+       u_int32_t  *currCache = NULL;
+       uintptr_t  blockRef;
+       u_int32_t  bitsPerBlock;
+       u_int32_t  wordsPerBlock;
        Boolean dirty = false;
+       struct hfsmount *hfsmp = VCBTOHFS(vcb);
+
+       /*
+        * When we're skipping the metadata zone and the start/end
+        * range overlaps with the metadata zone then adjust the 
+        * start to be outside of the metadata zone.  If the range
+        * is entirely inside the metadata zone then we can deny the
+        * request (dskFulErr).
+        */
+       if (!useMetaZone && (vcb->hfs_flags & HFS_METADATA_ZONE)) {
+               if (startingBlock <= vcb->hfs_metazone_end) {
+                       if (endingBlock > (vcb->hfs_metazone_end + 2))
+                               startingBlock = vcb->hfs_metazone_end + 1;
+                       else {
+                               err = dskFulErr;
+                               goto Exit;
+                       }
+               }
+       }
 
        //      Since this routine doesn't wrap around
        if (maxBlocks > (endingBlock - startingBlock)) {
@@ -601,15 +891,15 @@ static OSErr BlockAllocateAny(
        //
        //      Pre-read the first bitmap block
        //
-    err = ReadBitmapBlock(vcb, startingBlock, &currCache, &blockRef);
+       err = ReadBitmapBlock(vcb, startingBlock, &currCache, &blockRef);
        if (err != noErr) goto Exit;
-    buffer = currCache;
+       buffer = currCache;
 
        //
        //      Set up the current position within the block
        //
        {
-               UInt32 wordIndexInBlock;
+               u_int32_t wordIndexInBlock;
                
                bitsPerBlock  = vcb->vcbVBMIOSize * kBitsPerByte;
                wordsPerBlock = vcb->vcbVBMIOSize / kBytesPerWord;
@@ -628,7 +918,7 @@ static OSErr BlockAllocateAny(
        while (block < endingBlock) {
                if ((currentWord & bitMask) == 0)
                        break;
-               
+
                //      Next bit
                ++block;
                bitMask >>= 1;
@@ -636,27 +926,37 @@ static OSErr BlockAllocateAny(
                        //      Next word
                        bitMask = kHighBitInWordMask;
                        ++buffer;
-                       
+
                        if (--wordsLeft == 0) {
                                //      Next block
-                buffer = currCache = NULL;
+                               buffer = currCache = NULL;
                                err = ReleaseBitmapBlock(vcb, blockRef, false);
                                if (err != noErr) goto Exit;
 
-                err = ReadBitmapBlock(vcb, block, &currCache, &blockRef);
+                               /*
+                                * Skip over metadata blocks.
+                                */
+                               if (!useMetaZone) {
+                                       block = NextBitmapBlock(vcb, block);
+                               }
+                               if (block >= endingBlock) {
+                                       err = dskFulErr;
+                                       goto Exit;
+                               }
+
+                               err = ReadBitmapBlock(vcb, block, &currCache, &blockRef);
                                if (err != noErr) goto Exit;
-                buffer = currCache;
+                               buffer = currCache;
 
                                wordsLeft = wordsPerBlock;
                        }
-                       
                        currentWord = SWAP_BE32 (*buffer);
                }
        }
 
        //      Did we get to the end of the bitmap before finding a free block?
        //      If so, then couldn't allocate anything.
-       if (block == endingBlock) {
+       if (block >= endingBlock) {
                err = dskFulErr;
                goto Exit;
        }
@@ -673,6 +973,11 @@ static OSErr BlockAllocateAny(
                endingBlock = block + maxBlocks;        //      if we get this far, we've found enough
        }
        
+       // XXXdbg
+       if (hfsmp->jnl) {
+               journal_modify_block_start(hfsmp->jnl, (struct buf *)blockRef);
+       }
+
        //
        //      Allocate all of the consecutive blocks
        //
@@ -696,14 +1001,31 @@ static OSErr BlockAllocateAny(
                        
                        if (--wordsLeft == 0) {
                                //      Next block
-                buffer = currCache = NULL;
+                               buffer = currCache = NULL;
                                err = ReleaseBitmapBlock(vcb, blockRef, true);
                                if (err != noErr) goto Exit;
 
-                err = ReadBitmapBlock(vcb, block, &currCache, &blockRef);
+                               /*
+                                * Skip over metadata blocks.
+                                */
+                               if (!useMetaZone) {
+                                       u_int32_t nextBlock;
+
+                                       nextBlock = NextBitmapBlock(vcb, block);
+                                       if (nextBlock != block) {
+                                               goto Exit;  /* allocation gap, so stop */
+                                       }
+                               }
+
+                               err = ReadBitmapBlock(vcb, block, &currCache, &blockRef);
                                if (err != noErr) goto Exit;
-                buffer = currCache;
+                               buffer = currCache;
 
+                               // XXXdbg
+                               if (hfsmp->jnl) {
+                                       journal_modify_block_start(hfsmp->jnl, (struct buf *)blockRef);
+                               }
+                               
                                wordsLeft = wordsPerBlock;
                        }
                        
@@ -715,6 +1037,10 @@ static OSErr BlockAllocateAny(
 Exit:
        if (err == noErr) {
                *actualNumBlocks = block - *actualStartBlock;
+
+       // sanity check
+       if ((*actualStartBlock + *actualNumBlocks) > vcb->allocLimit)
+               panic("hfs: BlockAllocateAny: allocation overflow on \"%s\"", vcb->vcbVN);
        }
        else {
                *actualStartBlock = 0;
@@ -748,18 +1074,26 @@ Returns:
        dskFulErr               Free extent cache is empty
 _______________________________________________________________________
 */
+
 static OSErr BlockAllocateKnown(
        ExtendedVCB             *vcb,
-       UInt32                  maxBlocks,
-       UInt32                  *actualStartBlock,
-       UInt32                  *actualNumBlocks)
+       u_int32_t               maxBlocks,
+       u_int32_t               *actualStartBlock,
+       u_int32_t               *actualNumBlocks)
 {
-       UInt32                  i;
-       UInt32                  foundBlocks;
-       UInt32                  newStartBlock, newBlockCount;
-       
-       if (vcb->vcbFreeExtCnt == 0)
+       OSErr                   err;    
+       u_int32_t               i;
+       u_int32_t               foundBlocks;
+       u_int32_t               newStartBlock, newBlockCount;
+
+       HFS_MOUNT_LOCK(vcb, TRUE);
+       if (free_extent_cache_active(vcb) == 0 ||
+           vcb->vcbFreeExtCnt == 0 || 
+           vcb->vcbFreeExt[0].blockCount == 0) {
+               HFS_MOUNT_UNLOCK(vcb, TRUE);
                return dskFulErr;
+       }
+       HFS_MOUNT_UNLOCK(vcb, TRUE);
 
        //      Just grab up to maxBlocks of the first (largest) free exent.
        *actualStartBlock = vcb->vcbFreeExt[0].startBlock;
@@ -768,9 +1102,26 @@ static OSErr BlockAllocateKnown(
                foundBlocks = maxBlocks;
        *actualNumBlocks = foundBlocks;
        
+       if (vcb->hfs_flags & HFS_HAS_SPARSE_DEVICE) {
+               // since sparse volumes keep the free extent list sorted by starting
+               // block number, the list won't get re-ordered, it may only shrink
+               //
+               vcb->vcbFreeExt[0].startBlock += foundBlocks;
+               vcb->vcbFreeExt[0].blockCount -= foundBlocks;
+               if (vcb->vcbFreeExt[0].blockCount == 0) {
+                       for(i=1; i < vcb->vcbFreeExtCnt; i++) {
+                               vcb->vcbFreeExt[i-1] = vcb->vcbFreeExt[i];
+                       }
+                       vcb->vcbFreeExtCnt--;
+               }
+
+               goto done;
+       }
+
        //      Adjust the start and length of that extent.
        newStartBlock = vcb->vcbFreeExt[0].startBlock + foundBlocks;
        newBlockCount = vcb->vcbFreeExt[0].blockCount - foundBlocks;
+               
        
        //      The first extent might not be the largest anymore.  Bubble up any
        //      (now larger) extents to the top of the list.
@@ -790,9 +1141,9 @@ static OSErr BlockAllocateKnown(
        //      If this is now the smallest known free extent, then it might be smaller than
        //      other extents we didn't keep track of.  So, just forget about this extent.
        //      After the previous loop, (i-1) is the index of the extent we just allocated from.
-       if (i == vcb->vcbFreeExtCnt)
+       if (newBlockCount == 0)
        {
-               //      It's now the smallest extent, so forget about it
+               // then just reduce the number of free extents since this guy got deleted
                --vcb->vcbFreeExtCnt;
        }
        else
@@ -801,11 +1152,28 @@ static OSErr BlockAllocateKnown(
                vcb->vcbFreeExt[i-1].startBlock = newStartBlock;
                vcb->vcbFreeExt[i-1].blockCount = newBlockCount;
        }
-       
-       //
-       //      Now mark the found extent in the bitmap
-       //
-       return BlockMarkAllocated(vcb, *actualStartBlock, *actualNumBlocks);
+
+done:
+       // sanity check
+       if ((*actualStartBlock + *actualNumBlocks) > vcb->allocLimit) 
+       {
+               printf ("hfs: BlockAllocateKnown() found allocation overflow on \"%s\"", vcb->vcbVN);
+               hfs_mark_volume_inconsistent(vcb);
+               *actualStartBlock = 0;
+               *actualNumBlocks = 0;
+               err = EIO;
+       } 
+       else 
+       {
+               //
+               //      Now mark the found extent in the bitmap
+               //
+               err = BlockMarkAllocated(vcb, *actualStartBlock, *actualNumBlocks);
+       }
+
+       sanity_check_free_ext(vcb, 1);
+
+       return err;
 }
 
 
@@ -825,21 +1193,25 @@ Inputs:
        numBlocks               Number of blocks to mark as allocated
 _______________________________________________________________________
 */
-static OSErr BlockMarkAllocated(
+__private_extern__
+OSErr BlockMarkAllocated(
        ExtendedVCB             *vcb,
-       UInt32                  startingBlock,
-       register UInt32 numBlocks)
+       u_int32_t               startingBlock,
+       register u_int32_t      numBlocks)
 {
        OSErr                   err;
-       register UInt32 *currentWord;   //      Pointer to current word within bitmap block
-       register UInt32 wordsLeft;              //      Number of words left in this bitmap block
-       register UInt32 bitMask;                //      Word with given bits already set (ready to OR in)
-       UInt32                  firstBit;               //      Bit index within word of first bit to allocate
-       UInt32                  numBits;                //      Number of bits in word to allocate
-       UInt32                  *buffer = NULL;
-       UInt32  blockRef;
-       UInt32  bitsPerBlock;
-       UInt32  wordsPerBlock;
+       register u_int32_t      *currentWord;   //      Pointer to current word within bitmap block
+       register u_int32_t      wordsLeft;              //      Number of words left in this bitmap block
+       register u_int32_t      bitMask;                //      Word with given bits already set (ready to OR in)
+       u_int32_t               firstBit;               //      Bit index within word of first bit to allocate
+       u_int32_t               numBits;                //      Number of bits in word to allocate
+       u_int32_t               *buffer = NULL;
+       uintptr_t  blockRef;
+       u_int32_t  bitsPerBlock;
+       u_int32_t  wordsPerBlock;
+       // XXXdbg
+       struct hfsmount *hfsmp = VCBTOHFS(vcb);
+
 
        //
        //      Pre-read the bitmap block containing the first word of allocation
@@ -851,7 +1223,7 @@ static OSErr BlockMarkAllocated(
        //      Initialize currentWord, and wordsLeft.
        //
        {
-               UInt32 wordIndexInBlock;
+               u_int32_t wordIndexInBlock;
                
                bitsPerBlock  = vcb->vcbVBMIOSize * kBitsPerByte;
                wordsPerBlock = vcb->vcbVBMIOSize / kBytesPerWord;
@@ -861,6 +1233,11 @@ static OSErr BlockMarkAllocated(
                wordsLeft = wordsPerBlock - wordIndexInBlock;
        }
        
+       // XXXdbg
+       if (hfsmp->jnl) {
+               journal_modify_block_start(hfsmp->jnl, (struct buf *)blockRef);
+       }
+
        //
        //      If the first block to allocate doesn't start on a word
        //      boundary in the bitmap, then treat that first word
@@ -877,7 +1254,7 @@ static OSErr BlockMarkAllocated(
                }
 #if DEBUG_BUILD
                if ((*currentWord & SWAP_BE32 (bitMask)) != 0) {
-                       panic("BlockMarkAllocated: blocks already allocated!");
+                       panic("hfs: BlockMarkAllocated: blocks already allocated!");
                }
 #endif
                *currentWord |= SWAP_BE32 (bitMask);            //      set the bits in the bitmap
@@ -904,13 +1281,18 @@ static OSErr BlockMarkAllocated(
                        err = ReadBitmapBlock(vcb, startingBlock, &buffer, &blockRef);
                        if (err != noErr) goto Exit;
 
+                       // XXXdbg
+                       if (hfsmp->jnl) {
+                               journal_modify_block_start(hfsmp->jnl, (struct buf *)blockRef);
+                       }
+
                        //      Readjust currentWord and wordsLeft
                        currentWord = buffer;
                        wordsLeft = wordsPerBlock;
                }
 #if DEBUG_BUILD
                if (*currentWord != 0) {
-                       panic("BlockMarkAllocated: blocks already allocated!");
+                       panic("hfs: BlockMarkAllocated: blocks already allocated!");
                }
 #endif
                *currentWord = SWAP_BE32 (bitMask);
@@ -937,13 +1319,18 @@ static OSErr BlockMarkAllocated(
                        err = ReadBitmapBlock(vcb, startingBlock, &buffer, &blockRef);
                        if (err != noErr) goto Exit;
 
+                       // XXXdbg
+                       if (hfsmp->jnl) {
+                               journal_modify_block_start(hfsmp->jnl, (struct buf *)blockRef);
+                       }
+                       
                        //      Readjust currentWord and wordsLeft
                        currentWord = buffer;
                        wordsLeft = wordsPerBlock;
                }
 #if DEBUG_BUILD
                if ((*currentWord & SWAP_BE32 (bitMask)) != 0) {
-                       panic("BlockMarkAllocated: blocks already allocated!");
+                       panic("hfs: BlockMarkAllocated: blocks already allocated!");
                }
 #endif
                *currentWord |= SWAP_BE32 (bitMask);                    //      set the bits in the bitmap
@@ -975,21 +1362,41 @@ Inputs:
        numBlocks               Number of blocks to mark as freed
 _______________________________________________________________________
 */
-static OSErr BlockMarkFree(
+__private_extern__
+OSErr BlockMarkFree(
        ExtendedVCB             *vcb,
-       UInt32                  startingBlock,
-       register UInt32 numBlocks)
+       u_int32_t               startingBlock,
+       register u_int32_t      numBlocks)
 {
        OSErr                   err;
-       register UInt32 *currentWord;   //      Pointer to current word within bitmap block
-       register UInt32 wordsLeft;              //      Number of words left in this bitmap block
-       register UInt32 bitMask;                //      Word with given bits already set (ready to OR in)
-       UInt32                  firstBit;               //      Bit index within word of first bit to allocate
-       UInt32                  numBits;                //      Number of bits in word to allocate
-       UInt32                  *buffer = NULL;
-       UInt32  blockRef;
-       UInt32  bitsPerBlock;
-       UInt32  wordsPerBlock;
+       register u_int32_t      *currentWord;   //      Pointer to current word within bitmap block
+       register u_int32_t      wordsLeft;              //      Number of words left in this bitmap block
+       register u_int32_t      bitMask;                //      Word with given bits already set (ready to OR in)
+       u_int32_t                       firstBit;               //      Bit index within word of first bit to allocate
+       u_int32_t                       numBits;                //      Number of bits in word to allocate
+       u_int32_t                       *buffer = NULL;
+       uintptr_t  blockRef;
+       u_int32_t  bitsPerBlock;
+       u_int32_t  wordsPerBlock;
+    // XXXdbg
+       struct hfsmount *hfsmp = VCBTOHFS(vcb);
+       dk_discard_t discard;
+
+       /*
+        * NOTE: We use vcb->totalBlocks instead of vcb->allocLimit because we
+        * need to be able to free blocks being relocated during hfs_truncatefs.
+        */
+       if (startingBlock + numBlocks > vcb->totalBlocks) {
+               printf ("hfs: BlockMarkFree() trying to free non-existent blocks starting at %u (numBlock=%u) on volume %s\n", startingBlock, numBlocks, vcb->vcbVN);
+               hfs_mark_volume_inconsistent(vcb);
+               err = EIO;
+               goto Exit;
+       }
+
+       memset(&discard, 0, sizeof(dk_discard_t));
+       discard.offset = (uint64_t)startingBlock * (uint64_t)vcb->blockSize;
+       discard.length = (uint64_t)numBlocks * (uint64_t)vcb->blockSize;
+
 
        //
        //      Pre-read the bitmap block containing the first word of allocation
@@ -997,11 +1404,16 @@ static OSErr BlockMarkFree(
 
        err = ReadBitmapBlock(vcb, startingBlock, &buffer, &blockRef);
        if (err != noErr) goto Exit;
+       // XXXdbg
+       if (hfsmp->jnl) {
+               journal_modify_block_start(hfsmp->jnl, (struct buf *)blockRef);
+       }
+
        //
        //      Initialize currentWord, and wordsLeft.
        //
        {
-               UInt32 wordIndexInBlock;
+               u_int32_t wordIndexInBlock;
                
                bitsPerBlock  = vcb->vcbVBMIOSize * kBitsPerByte;
                wordsPerBlock = vcb->vcbVBMIOSize / kBytesPerWord;
@@ -1025,11 +1437,9 @@ static OSErr BlockMarkFree(
                        numBits = numBlocks;                                    //      entire allocation is inside this one word
                        bitMask &= ~(kAllBitsSetInWord >> (firstBit + numBits));        //      turn off bits after last
                }
-#if DEBUG_BUILD
                if ((*currentWord & SWAP_BE32 (bitMask)) != SWAP_BE32 (bitMask)) {
-                       panic("BlockMarkFree: blocks not allocated!");
+                       goto Corruption;
                }
-#endif
                *currentWord &= SWAP_BE32 (~bitMask);           //      clear the bits in the bitmap
                numBlocks -= numBits;                                           //      adjust number of blocks left to free
 
@@ -1053,16 +1463,18 @@ static OSErr BlockMarkFree(
                        err = ReadBitmapBlock(vcb, startingBlock, &buffer, &blockRef);
                        if (err != noErr) goto Exit;
 
+                       // XXXdbg
+                       if (hfsmp->jnl) {
+                               journal_modify_block_start(hfsmp->jnl, (struct buf *)blockRef);
+                       }
+
                        //      Readjust currentWord and wordsLeft
                        currentWord = buffer;
                        wordsLeft = wordsPerBlock;
                }
-
-#if DEBUG_BUILD
                if (*currentWord != SWAP_BE32 (kAllBitsSetInWord)) {
-                       panic("BlockMarkFree: blocks not allocated!");
+                       goto Corruption;
                }
-#endif
                *currentWord = 0;                                                       //      clear the entire word
                numBlocks -= kBitsPerWord;
                
@@ -1087,15 +1499,18 @@ static OSErr BlockMarkFree(
                        err = ReadBitmapBlock(vcb, startingBlock, &buffer, &blockRef);
                        if (err != noErr) goto Exit;
 
+                       // XXXdbg
+                       if (hfsmp->jnl) {
+                               journal_modify_block_start(hfsmp->jnl, (struct buf *)blockRef);
+                       }
+                       
                        //      Readjust currentWord and wordsLeft
                        currentWord = buffer;
                        wordsLeft = wordsPerBlock;
                }
-#if DEBUG_BUILD
                if ((*currentWord & SWAP_BE32 (bitMask)) != SWAP_BE32 (bitMask)) {
-                       panic("BlockMarkFree: blocks not allocated!");
+                       goto Corruption;
                }
-#endif
                *currentWord &= SWAP_BE32 (~bitMask);                   //      clear the bits in the bitmap
 
                //      No need to update currentWord or wordsLeft
@@ -1106,7 +1521,23 @@ Exit:
        if (buffer)
                (void)ReleaseBitmapBlock(vcb, blockRef, true);
 
+       if (err == noErr) {
+               // it doesn't matter if this fails, it's just informational anyway
+               VNOP_IOCTL(vcb->hfs_devvp, DKIOCDISCARD, (caddr_t)&discard, 0, vfs_context_kernel());
+       }
+
+
        return err;
+
+Corruption:
+#if DEBUG_BUILD
+       panic("hfs: BlockMarkFree: blocks not allocated!");
+#else
+       printf ("hfs: BlockMarkFree() trying to free unallocated blocks on volume %s\n", vcb->vcbVN);
+       hfs_mark_volume_inconsistent(vcb);
+       err = EIO;
+       goto Exit;
+#endif
 }
 
 
@@ -1125,6 +1556,7 @@ Inputs:
        endingBlock             Last possible block in range + 1
        minBlocks               Minimum number of blocks needed.  Must be > 0.
        maxBlocks               Maximum (ideal) number of blocks desired
+       useMetaZone     OK to dip into metadata allocation zone
 
 Outputs:
        actualStartBlock        First block of range found, or 0 if error
@@ -1138,25 +1570,43 @@ _______________________________________________________________________
 
 static OSErr BlockFindContiguous(
        ExtendedVCB             *vcb,
-       UInt32                  startingBlock,
-       UInt32                  endingBlock,
-       UInt32                  minBlocks,
-       UInt32                  maxBlocks,
-       UInt32                  *actualStartBlock,
-       UInt32                  *actualNumBlocks)
+       u_int32_t               startingBlock,
+       u_int32_t               endingBlock,
+       u_int32_t               minBlocks,
+       u_int32_t               maxBlocks,
+       Boolean                 useMetaZone,
+       u_int32_t               *actualStartBlock,
+       u_int32_t               *actualNumBlocks)
 {
        OSErr                   err;
-       register UInt32 currentBlock;           //      Block we're currently looking at.
-       UInt32                  firstBlock;                     //      First free block in current extent.
-       UInt32                  stopBlock;                      //      If we get to this block, stop searching for first free block.
-       UInt32                  foundBlocks;            //      Number of contiguous free blocks in current extent.
-       UInt32                  *buffer = NULL;
-       register UInt32 *currentWord;
-       register UInt32 bitMask;
-       register UInt32 wordsLeft;
-       register UInt32 tempWord;
-       UInt32  blockRef;
-       UInt32  wordsPerBlock;
+       register u_int32_t      currentBlock;           //      Block we're currently looking at.
+       u_int32_t                       firstBlock;                     //      First free block in current extent.
+       u_int32_t                       stopBlock;                      //      If we get to this block, stop searching for first free block.
+       u_int32_t                       foundBlocks;            //      Number of contiguous free blocks in current extent.
+       u_int32_t                       *buffer = NULL;
+       register u_int32_t      *currentWord;
+       register u_int32_t      bitMask;
+       register u_int32_t      wordsLeft;
+       register u_int32_t      tempWord;
+       uintptr_t  blockRef;
+       u_int32_t  wordsPerBlock;
+       u_int32_t  j, updated_free_extents = 0, really_add;
+
+       /*
+        * When we're skipping the metadata zone and the start/end
+        * range overlaps with the metadata zone then adjust the 
+        * start to be outside of the metadata zone.  If the range
+        * is entirely inside the metadata zone then we can deny the
+        * request (dskFulErr).
+        */
+       if (!useMetaZone && (vcb->hfs_flags & HFS_METADATA_ZONE)) {
+               if (startingBlock <= vcb->hfs_metazone_end) {
+                       if (endingBlock > (vcb->hfs_metazone_end + 2))
+                               startingBlock = vcb->hfs_metazone_end + 1;
+                       else
+                               goto DiskFull;
+               }
+       }
 
        if ((endingBlock - startingBlock) < minBlocks)
        {
@@ -1167,7 +1617,14 @@ static OSErr BlockFindContiguous(
 
        stopBlock = endingBlock - minBlocks + 1;
        currentBlock = startingBlock;
-       
+       firstBlock = 0;
+
+       /*
+        * Skip over metadata blocks.
+        */
+       if (!useMetaZone)
+               currentBlock = NextBitmapBlock(vcb, currentBlock);
+
        //
        //      Pre-read the first bitmap block.
        //
@@ -1179,7 +1636,7 @@ static OSErr BlockFindContiguous(
        //
        wordsPerBlock = vcb->vcbVBMIOSize / kBytesPerWord;
 
-       wordsLeft = (startingBlock / kBitsPerWord) & (wordsPerBlock-1); // Current index into buffer
+       wordsLeft = (currentBlock / kBitsPerWord) & (wordsPerBlock-1);  // Current index into buffer
        currentWord = buffer + wordsLeft;
        wordsLeft = wordsPerBlock - wordsLeft;
        
@@ -1197,7 +1654,7 @@ static OSErr BlockFindContiguous(
                bitMask = currentBlock & kBitsWithinWordMask;
                if (bitMask)
                {                       
-                       tempWord = *currentWord;                        //      Fetch the current word only once
+                       tempWord = SWAP_BE32(*currentWord);                     //      Fetch the current word only once
                        bitMask = kHighBitInWordMask >> bitMask;
                        while (tempWord & bitMask)
                        {
@@ -1226,6 +1683,16 @@ static OSErr BlockFindContiguous(
                                err = ReleaseBitmapBlock(vcb, blockRef, false);
                                if (err != noErr) goto ErrorExit;
 
+                               /*
+                                * Skip over metadata blocks.
+                                */
+                               if (!useMetaZone) {
+                                       currentBlock = NextBitmapBlock(vcb, currentBlock);
+                                       if (currentBlock >= stopBlock) {
+                                               goto LoopExit;
+                                       }
+                               }
+
                                err = ReadBitmapBlock(vcb, currentBlock, &buffer, &blockRef);
                                if ( err != noErr ) goto ErrorExit;
                                
@@ -1234,7 +1701,7 @@ static OSErr BlockFindContiguous(
                        }
                        
                        //      See if any of the bits are clear
-                       if ((tempWord=*currentWord) + 1)        //      non-zero if any bits were clear
+                       if ((tempWord = SWAP_BE32(*currentWord)) + 1)   //      non-zero if any bits were clear
                        {
                                //      Figure out which bit is clear
                                bitMask = kHighBitInWordMask;
@@ -1273,7 +1740,7 @@ FoundUnused:
                bitMask = currentBlock & kBitsWithinWordMask;
                if (bitMask)
                {
-                       tempWord = *currentWord;                        //      Fetch the current word only once
+                       tempWord = SWAP_BE32(*currentWord);                     //      Fetch the current word only once
                        bitMask = kHighBitInWordMask >> bitMask;
                        while (bitMask && !(tempWord & bitMask))
                        {
@@ -1302,6 +1769,18 @@ FoundUnused:
                                err = ReleaseBitmapBlock(vcb, blockRef, false);
                                if (err != noErr) goto ErrorExit;
 
+                               /*
+                                * Skip over metadata blocks.
+                                */
+                               if (!useMetaZone) {
+                                       u_int32_t nextBlock;
+
+                                       nextBlock = NextBitmapBlock(vcb, currentBlock);
+                                       if (nextBlock != currentBlock) {
+                                               goto LoopExit;  /* allocation gap, so stop */
+                                       }
+                               }
+
                                err = ReadBitmapBlock(vcb, currentBlock, &buffer, &blockRef);
                                if ( err != noErr ) goto ErrorExit;
                                
@@ -1310,7 +1789,7 @@ FoundUnused:
                        }
                        
                        //      See if any of the bits are set
-                       if ((tempWord=*currentWord) != 0)
+                       if ((tempWord = SWAP_BE32(*currentWord)) != 0)
                        {
                                //      Figure out which bit is set
                                bitMask = kHighBitInWordMask;
@@ -1347,27 +1826,82 @@ FoundUsed:
                if (foundBlocks >= minBlocks)
                        break;          //      Found what we needed!
 
+               HFS_MOUNT_LOCK(vcb, TRUE);
+               if (free_extent_cache_active(vcb) == 0) {
+                       HFS_MOUNT_UNLOCK(vcb, TRUE);
+                       goto skip_cache;
+               }
+               HFS_MOUNT_UNLOCK(vcb, TRUE);
+
                //      This free chunk wasn't big enough.  Try inserting it into the free extent cache in case
                //      the allocation wasn't forced contiguous.
+               really_add = 0;
+               for(j=0; j < vcb->vcbFreeExtCnt; j++) {
+                       u_int32_t start, end;
+
+                       start = vcb->vcbFreeExt[j].startBlock;
+                       end   = start + vcb->vcbFreeExt[j].blockCount;
+
+                       if (   (firstBlock >= start && firstBlock < end)
+                           || ((firstBlock + foundBlocks) > start && firstBlock < start)) {
+
+                               // there's overlap with an existing entry so do not add this
+                               break;
+                       }
+                       
+               }
+
+               if (j >= vcb->vcbFreeExtCnt) {
+                       really_add = 1;
+               }
+
                tempWord = vcb->vcbFreeExtCnt;
-               if (tempWord == kMaxFreeExtents && vcb->vcbFreeExt[kMaxFreeExtents-1].blockCount < foundBlocks)
-                       --tempWord;
-               if (tempWord < kMaxFreeExtents)
-               {
-                       //      We're going to add this extent.  Bubble any smaller extents down in the list.
-                       while (tempWord && vcb->vcbFreeExt[tempWord-1].blockCount < foundBlocks)
-                       {
-                               vcb->vcbFreeExt[tempWord] = vcb->vcbFreeExt[tempWord-1];
+               if (really_add && (vcb->hfs_flags & HFS_HAS_SPARSE_DEVICE)) {
+                       // Sorted by starting block
+                       if (tempWord == kMaxFreeExtents && vcb->vcbFreeExt[kMaxFreeExtents-1].startBlock > firstBlock)
                                --tempWord;
+                       if (tempWord < kMaxFreeExtents)
+                       {
+                               //      We're going to add this extent.  Bubble any smaller extents down in the list.
+                               while (tempWord && vcb->vcbFreeExt[tempWord-1].startBlock > firstBlock)
+                               {
+                                       vcb->vcbFreeExt[tempWord] = vcb->vcbFreeExt[tempWord-1];
+                                       --tempWord;
+                               }
+                               vcb->vcbFreeExt[tempWord].startBlock = firstBlock;
+                               vcb->vcbFreeExt[tempWord].blockCount = foundBlocks;
+                       
+                               if (vcb->vcbFreeExtCnt < kMaxFreeExtents) {
+                                       ++vcb->vcbFreeExtCnt;
+                               }
+                               updated_free_extents = 1;
                        }
-                       vcb->vcbFreeExt[tempWord].startBlock = firstBlock;
-                       vcb->vcbFreeExt[tempWord].blockCount = foundBlocks;
+               } else if (really_add) {
+                       // Sorted by blockCount
+                       if (tempWord == kMaxFreeExtents && vcb->vcbFreeExt[kMaxFreeExtents-1].blockCount < foundBlocks)
+                               --tempWord;
+                       if (tempWord < kMaxFreeExtents)
+                       {
+                               //      We're going to add this extent.  Bubble any smaller extents down in the list.
+                               while (tempWord && vcb->vcbFreeExt[tempWord-1].blockCount < foundBlocks)
+                               {
+                                       vcb->vcbFreeExt[tempWord] = vcb->vcbFreeExt[tempWord-1];
+                                       --tempWord;
+                               }
+                               vcb->vcbFreeExt[tempWord].startBlock = firstBlock;
+                               vcb->vcbFreeExt[tempWord].blockCount = foundBlocks;
                        
-                       if (vcb->vcbFreeExtCnt < kMaxFreeExtents)
-                               ++vcb->vcbFreeExtCnt;
+                               if (vcb->vcbFreeExtCnt < kMaxFreeExtents) {
+                                       ++vcb->vcbFreeExtCnt;
+                               }
+                               updated_free_extents = 1;
+                       }
                }
-       } while (currentBlock < stopBlock);
+skip_cache:
+               sanity_check_free_ext(vcb, 0);
 
+       } while (currentBlock < stopBlock);
+LoopExit:
 
        //      Return the outputs.
        if (foundBlocks < minBlocks)
@@ -1383,12 +1917,203 @@ ErrorExit:
                err = noErr;
                *actualStartBlock = firstBlock;
                *actualNumBlocks = foundBlocks;
+               /*
+                * Sanity check for overflow
+                */
+               if ((firstBlock + foundBlocks) > vcb->allocLimit) {
+                       panic("hfs: blk allocation overflow on \"%s\" sb:0x%08x eb:0x%08x cb:0x%08x fb:0x%08x stop:0x%08x min:0x%08x found:0x%08x",
+                               vcb->vcbVN, startingBlock, endingBlock, currentBlock,
+                               firstBlock, stopBlock, minBlocks, foundBlocks);
+               }
+       }
+       
+       if (updated_free_extents && (vcb->hfs_flags & HFS_HAS_SPARSE_DEVICE)) {
+               int i;
+               u_int32_t min_start = vcb->totalBlocks;
+                       
+               // set the nextAllocation pointer to the smallest free block number
+               // we've seen so on the next mount we won't rescan unnecessarily
+               for(i=0; i < (int)vcb->vcbFreeExtCnt; i++) {
+                       if (vcb->vcbFreeExt[i].startBlock < min_start) {
+                               min_start = vcb->vcbFreeExt[i].startBlock;
+                       }
+               }
+               if (min_start != vcb->totalBlocks) {
+                       if (min_start < vcb->nextAllocation) {
+                               vcb->nextAllocation = min_start;
+                       }
+                       if (min_start < vcb->sparseAllocation) {
+                               vcb->sparseAllocation = min_start;
+                       }
+               }
        }
        
        if (buffer)
                (void) ReleaseBitmapBlock(vcb, blockRef, false);
 
+       sanity_check_free_ext(vcb, 1);
+
        return err;
 }
 
+/*
+ * Test to see if any blocks in a range are allocated.
+ *
+ * The journal or allocation file lock must be held.
+ */
+__private_extern__
+int 
+hfs_isallocated(struct hfsmount *hfsmp, u_int32_t startingBlock, u_int32_t numBlocks)
+{
+       u_int32_t  *currentWord;   // Pointer to current word within bitmap block
+       u_int32_t  wordsLeft;      // Number of words left in this bitmap block
+       u_int32_t  bitMask;        // Word with given bits already set (ready to test)
+       u_int32_t  firstBit;       // Bit index within word of first bit to allocate
+       u_int32_t  numBits;        // Number of bits in word to allocate
+       u_int32_t  *buffer = NULL;
+       uintptr_t  blockRef;
+       u_int32_t  bitsPerBlock;
+       u_int32_t  wordsPerBlock;
+       int  inuse = 0;
+       int  error;
+
+       /*
+        * Pre-read the bitmap block containing the first word of allocation
+        */
+       error = ReadBitmapBlock(hfsmp, startingBlock, &buffer, &blockRef);
+       if (error)
+               return (error);
+
+       /*
+        * Initialize currentWord, and wordsLeft.
+        */
+       {
+               u_int32_t wordIndexInBlock;
+               
+               bitsPerBlock  = hfsmp->vcbVBMIOSize * kBitsPerByte;
+               wordsPerBlock = hfsmp->vcbVBMIOSize / kBytesPerWord;
+
+               wordIndexInBlock = (startingBlock & (bitsPerBlock-1)) / kBitsPerWord;
+               currentWord = buffer + wordIndexInBlock;
+               wordsLeft = wordsPerBlock - wordIndexInBlock;
+       }
+       
+       /*
+        * First test any non word aligned bits.
+        */
+       firstBit = startingBlock % kBitsPerWord;
+       if (firstBit != 0) {
+               bitMask = kAllBitsSetInWord >> firstBit;
+               numBits = kBitsPerWord - firstBit;
+               if (numBits > numBlocks) {
+                       numBits = numBlocks;
+                       bitMask &= ~(kAllBitsSetInWord >> (firstBit + numBits));
+               }
+               if ((*currentWord & SWAP_BE32 (bitMask)) != 0) {
+                       inuse = 1;
+                       goto Exit;
+               }
+               numBlocks -= numBits;
+               ++currentWord;
+               --wordsLeft;
+       }
+
+       /*
+        * Test whole words (32 blocks) at a time.
+        */
+       while (numBlocks >= kBitsPerWord) {
+               if (wordsLeft == 0) {
+                       /* Read in the next bitmap block. */
+                       startingBlock += bitsPerBlock;
+                       
+                       buffer = NULL;
+                       error = ReleaseBitmapBlock(hfsmp, blockRef, false);
+                       if (error) goto Exit;
+
+                       error = ReadBitmapBlock(hfsmp, startingBlock, &buffer, &blockRef);
+                       if (error) goto Exit;
+
+                       /* Readjust currentWord and wordsLeft. */
+                       currentWord = buffer;
+                       wordsLeft = wordsPerBlock;
+               }
+               if (*currentWord != 0) {
+                       inuse = 1;
+                       goto Exit;
+               }
+               numBlocks -= kBitsPerWord;
+               ++currentWord;
+               --wordsLeft;
+       }
+       
+       /*
+        * Test any remaining blocks.
+        */
+       if (numBlocks != 0) {
+               bitMask = ~(kAllBitsSetInWord >> numBlocks);
+               if (wordsLeft == 0) {
+                       /* Read in the next bitmap block */
+                       startingBlock += bitsPerBlock;
+                       
+                       buffer = NULL;
+                       error = ReleaseBitmapBlock(hfsmp, blockRef, false);
+                       if (error) goto Exit;
+
+                       error = ReadBitmapBlock(hfsmp, startingBlock, &buffer, &blockRef);
+                       if (error) goto Exit;
+
+                       currentWord = buffer;
+                       wordsLeft = wordsPerBlock;
+               }
+               if ((*currentWord & SWAP_BE32 (bitMask)) != 0) {
+                       inuse = 1;
+                       goto Exit;
+               }
+       }
+Exit:
+       if (buffer) {
+               (void)ReleaseBitmapBlock(hfsmp, blockRef, false);
+       }
+       return (inuse);
+}
+
+/* Invalidate free extent cache for a given volume.
+ * This cache is invalidated and disabled when a volume is being resized 
+ * (via hfs_trucatefs() or hfs_extendefs()).
+ *
+ * Returns: Nothing
+ */
+void invalidate_free_extent_cache(ExtendedVCB *vcb)
+{
+       u_int32_t i;
 
+       HFS_MOUNT_LOCK(vcb, TRUE);
+       for (i = 0; i < vcb->vcbFreeExtCnt; i++) {
+               vcb->vcbFreeExt[i].startBlock = 0;
+               vcb->vcbFreeExt[i].blockCount = 0;
+       }
+       vcb->vcbFreeExtCnt = 0;
+       HFS_MOUNT_UNLOCK(vcb, TRUE);
+
+       return;
+}
+
+/* Check whether free extent cache is active or not. 
+ * This cache is invalidated and disabled when a volume is being resized 
+ * (via hfs_trucatefs() or hfs_extendefs()).
+ *
+ * This function assumes that the caller is holding the lock on 
+ * the mount point.
+ *
+ * Returns: 0 if the cache is not active,
+ *          1 if the cache is active.
+ */
+static int free_extent_cache_active(ExtendedVCB *vcb)
+{
+       int retval = 1;
+
+       if (vcb->hfs_flags & HFS_RESIZE_IN_PROGRESS) {
+               retval = 0;
+       }
+       return retval;
+}