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windows-xp/Source/XPSP1/NT/base/ntos/config/hivehint.c

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/*++
Copyright (c) 1999 Microsoft Corporation
Module Name:
hivehint.c
Abstract:
This module contains free space display support.
Author:
Dragos C. Sambotin (dragoss) 15-Jul-1999
Revision History:
--*/
#include "cmp.h"
NTSTATUS
HvpAdjustBitmap(
IN PHHIVE Hive,
IN ULONG HiveLength,
IN OUT PRTL_BITMAP Bitmap
);
HCELL_INDEX
HvpFindFreeCellInBin(
PHHIVE Hive,
ULONG Index,
ULONG NewSize,
HSTORAGE_TYPE Type,
PHBIN Bin
);
HCELL_INDEX
HvpFindFreeCellInThisViewWindow(
PHHIVE Hive,
ULONG Index,
ULONG NewSize,
HSTORAGE_TYPE Type,
HCELL_INDEX Vicinity
);
HCELL_INDEX
HvpScanForFreeCellInViewWindow(
PHHIVE Hive,
ULONG Index,
ULONG NewSize,
HSTORAGE_TYPE Type,
HCELL_INDEX FileOffsetStart
);
#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE,HvpAdjustHiveFreeDisplay)
#pragma alloc_text(PAGE,HvpFreeHiveFreeDisplay)
#pragma alloc_text(PAGE,HvpAdjustBitmap)
#pragma alloc_text(PAGE,HvpAddFreeCellHint)
#pragma alloc_text(PAGE,HvpRemoveFreeCellHint)
#pragma alloc_text(PAGE,HvpFindFreeCellInBin)
#pragma alloc_text(PAGE,HvpFindFreeCellInThisViewWindow)
#pragma alloc_text(PAGE,HvpScanForFreeCellInViewWindow)
#pragma alloc_text(PAGE,HvpCheckViewBoundary)
#pragma alloc_text(PAGE,HvpFindFreeCell)
#endif
NTSTATUS
HvpAdjustHiveFreeDisplay(
IN PHHIVE Hive,
IN ULONG HiveLength,
IN HSTORAGE_TYPE Type
)
/*++
Routine Description:
calls HvpAdjustBitmap for all bitmap sizes
!!! - to be called when the size of the hive changes (shrink or grow case).
Arguments:
Hive - used for quota tracking.
HiveLength - the new length of the hive.
Type - Stable or Volatile.
Return Value:
NTSTATUS code.
--*/
{
ULONG i;
NTSTATUS Status;
PAGED_CODE();
for (i = 0; i < HHIVE_FREE_DISPLAY_SIZE; i++) {
Status = HvpAdjustBitmap(Hive,HiveLength,&(Hive->Storage[Type].FreeDisplay[i]) );
if( !NT_SUCCESS(Status) ){
return Status;
}
}
return STATUS_SUCCESS;
}
#define ROUND_UP_NOZERO(a, b) (a)?ROUND_UP(a,b):(b)
#define ROUND_INCREMENTS 0x100
VOID
HvpFreeHiveFreeDisplay(
IN PHHIVE Hive
)
/*++
Routine Description:
Frees the storage allocated for the free display bitmaps
Arguments:
Hive - used for quota tracking.
Return Value:
NTSTATUS code.
--*/
{
ULONG i,j;
NTSTATUS Status;
ULONG BufferSize;
PAGED_CODE();
for( i=Stable;i<=Volatile;i++) {
//
// we may loose some quota here; due to rounding
// we can prevent that by keeping the real size of
// the bitmaps as a member of the hive struct
//
BufferSize = ROUND_UP_NOZERO(Hive->Storage[i].FreeDisplay[0].SizeOfBitMap / 8,ROUND_INCREMENTS);
for (j = 0; j < HHIVE_FREE_DISPLAY_SIZE; j++) {
if( Hive->Storage[i].FreeDisplay[j].Buffer != NULL ) {
(Hive->Free)(Hive->Storage[i].FreeDisplay[j].Buffer, BufferSize);
}
}
}
return;
}
NTSTATUS
HvpAdjustBitmap(
IN PHHIVE Hive,
IN ULONG HiveLength,
IN OUT PRTL_BITMAP Bitmap
)
/*++
Routine Description:
When the length of the hive grows/shrinks, adjust the bitmap accordingly.
- allocates a bitmap buffer large enough.
- copies the relevant information from the old bitmap.
Arguments:
Hive - used for quota tracking.
HiveLength - the new length of the hive.
Bitmap - bitmap to operate on.
Return Value:
NTSTATUS code.
--*/
{
ULONG VectorSize;
ULONG NewBufferSize;
ULONG OldBufferSize;
PULONG Vector;
PULONG OldVector;
ULONG OldVectorSize;
PAGED_CODE();
VectorSize = HiveLength / HBLOCK_SIZE; // Vector size == bits
NewBufferSize = ROUND_UP_NOZERO( (VectorSize + 7) / 8,ROUND_INCREMENTS); // BufferSize == Bytes
if( Bitmap->SizeOfBitMap == 0 ) {
OldBufferSize = 0;
} else {
OldBufferSize = ROUND_UP_NOZERO( (Bitmap->SizeOfBitMap + 7) / 8, ROUND_INCREMENTS);
}
if( NewBufferSize <= OldBufferSize ) {
//
// We don't shrink the vector; next time we grow, we'll perform
// the adjustments
//
//
// Clear all the unused bits and return;
//
// we don't really need to do this as nobody will write in here
// we'll drop it in the final implementation
//
OldVectorSize = Bitmap->SizeOfBitMap;
//
// set the new size
//
RtlInitializeBitMap(Bitmap,Bitmap->Buffer,VectorSize);
if( OldVectorSize < VectorSize ) {
RtlClearBits (Bitmap,OldVectorSize,VectorSize - OldVectorSize);
}
return STATUS_SUCCESS;
}
//
// else, the bitmap has enlarged. Allocate a new buffer and copy the bits already set.
//
Vector = (PULONG)((Hive->Allocate)(NewBufferSize, TRUE,CM_FIND_LEAK_TAG39));
if (Vector == NULL) {
return STATUS_INSUFFICIENT_RESOURCES;
}
OldVector = Bitmap->Buffer;
//CmKdPrintEx((DPFLTR_CONFIG_ID,DPFLTR_TRACE_LEVEL,"HvpAdjustBitmap: Old %lu :: %lu (%lx) New %lu :: %lu (%lx)\n",OldBufferSize,Bitmap->SizeOfBitMap,OldVector,NewBufferSize,VectorSize,Vector));
RtlZeroMemory(Vector,NewBufferSize);
RtlInitializeBitMap(Bitmap, Vector, VectorSize);
if( OldVector != NULL ) {
//
// copy the already set bits
//
RtlCopyMemory (Vector,OldVector,OldBufferSize);
//
// Free the old vector
//
(Hive->Free)(OldVector, OldBufferSize);
}
return STATUS_SUCCESS;
}
VOID
HvpAddFreeCellHint(
PHHIVE Hive,
HCELL_INDEX Cell,
ULONG Index,
HSTORAGE_TYPE Type
)
/*++
Routine Description:
Sets the corresponding bit in the bitmap
Arguments:
Hive - hive operating on
Cell - free cell
Index - index in FreeDisplay (based on the free cell size)
Type - storage type (Stable or Volatile)
Return Value:
VOID
--*/
{
ULONG BinIndex;
PHMAP_ENTRY Me;
PHBIN Bin;
PAGED_CODE();
Me = HvpGetCellMap(Hive, Cell);
VALIDATE_CELL_MAP(__LINE__,Me,Hive,Cell);
Bin = (PHBIN)HBIN_BASE(Me->BinAddress);
//
// compute the bin index and for the begining of the bin
//
BinIndex = Bin->FileOffset / HBLOCK_SIZE;
RtlSetBits (&(Hive->Storage[Type].FreeDisplay[Index]), BinIndex, Bin->Size / HBLOCK_SIZE);
Hive->Storage[Type].FreeSummary |= (1 << Index);
}
VOID
HvpRemoveFreeCellHint(
PHHIVE Hive,
HCELL_INDEX Cell,
ULONG Index,
HSTORAGE_TYPE Type
)
/*++
Routine Description:
Clears the corresponding bit in the bitmap
Arguments:
Hive - hive operating on
Cell - free cell
Index - index in FreeDisplay (based on the free cell size)
Type - storage type (Stable or Volatile)
Return Value:
VOID
--*/
{
ULONG BinIndex;
ULONG TempIndex;
PHMAP_ENTRY Me;
PHBIN Bin;
ULONG CellOffset;
ULONG Size;
PHCELL p;
BOOLEAN CellFound = FALSE;
PAGED_CODE();
Me = HvpGetCellMap(Hive, Cell);
VALIDATE_CELL_MAP(__LINE__,Me,Hive,Cell);
Bin = (PHBIN)HBIN_BASE(Me->BinAddress);
CellOffset = Bin->FileOffset + sizeof(HBIN);
#ifdef CM_MAP_NO_READ
//
// we ned to be protected against exception raised by the FS while faulting in data
//
try {
#endif //CM_MAP_NO_READ
//
// There is a chance we can find a suitable free cell
//
p = (PHCELL)((PUCHAR)Bin + sizeof(HBIN));
while (p < (PHCELL)((PUCHAR)Bin + Bin->Size)) {
//
// if free cell, check it out, add it to free list for hive
//
if (p->Size >= 0) {
Size = (ULONG)p->Size;
HvpComputeIndex(TempIndex, Size);
if ((Index == TempIndex) && (CellOffset != (Cell&(~HCELL_TYPE_MASK)) )) {
//
// there is at least one free cell of this size (this one)
// different than the one being delisted
//
CellFound = TRUE;
break;
}
} else {
//
// used cell
//
Size = (ULONG)(p->Size * -1);
}
ASSERT( ((LONG)Size) >= 0);
p = (PHCELL)((PUCHAR)p + Size);
CellOffset += Size;
}
#ifdef CM_MAP_NO_READ
} except (EXCEPTION_EXECUTE_HANDLER) {
CmKdPrintEx((DPFLTR_CONFIG_ID,DPFLTR_ERROR_LEVEL,"HvpRemoveFreeCellHint: exception thrown ehile faulting in data, code:%08lx\n", GetExceptionCode()));
//
// better not use cells inthis range rather than leaving false hints
//
CellFound = FALSE;
}
#endif //CM_MAP_NO_READ
if( CellFound == FALSE ) {
//
// no cell with this index was found
// compute the bin index and for the begining of the bin
//
BinIndex = Bin->FileOffset / HBLOCK_SIZE;
RtlClearBits (&(Hive->Storage[Type].FreeDisplay[Index]), BinIndex, Bin->Size / HBLOCK_SIZE);
}
if( RtlNumberOfSetBits(&(Hive->Storage[Type].FreeDisplay[Index]) ) != 0 ) {
//
// there are still some other free cells of this size
//
Hive->Storage[Type].FreeSummary |= (1 << Index);
} else {
//
// entire bitmap is 0 (i.e. no other free cells of this size)
//
Hive->Storage[Type].FreeSummary &= (~(1 << Index));
}
}
HCELL_INDEX
HvpFindFreeCellInBin(
PHHIVE Hive,
ULONG Index,
ULONG NewSize,
HSTORAGE_TYPE Type,
PHBIN Bin
)
/*++
Routine Description:
Lookup for a free cell with the size NewSize in this particular bin
Arguments:
Hive - target hive.
Index - index in FreeDisplay (based on the free cell size)
NewSize - desired size
Type - storage type (Stable or Volatile)
Bin - Bin in question
Return Value:
A free cellindex with a size bigger than NewSize, or HCELL_NIL
--*/
{
ULONG BinIndex;
ULONG CellOffset;
PHCELL p;
ULONG BinOffset;
ULONG Size;
HCELL_INDEX cellindex;
ULONG FoundCellIndex;
PAGED_CODE();
BinOffset = Bin->FileOffset;
BinIndex = BinOffset/HBLOCK_SIZE;
if( RtlCheckBit(&(Hive->Storage[Type].FreeDisplay[Index]), BinIndex) == 0 ) {
//
// no hint for this bin
//
return HCELL_NIL;
}
CellOffset = sizeof(HBIN);
#ifdef CM_MAP_NO_READ
//
// we ned to be protected against exception raised by the FS while faulting in data
//
try {
#endif //CM_MAP_NO_READ
//
// There is a chance we can find a suitable free cell
//
p = (PHCELL)((PUCHAR)Bin + sizeof(HBIN));
while (p < (PHCELL)((PUCHAR)Bin + Bin->Size)) {
//
// if free cell, check it out, add it to free list for hive
//
if (p->Size >= 0) {
Size = (ULONG)p->Size;
//
// cell is free, and is not obviously corrupt, add to free list
//
CellOffset = (ULONG)((PUCHAR)p - (PUCHAR)Bin);
cellindex = BinOffset + CellOffset + (Type*HCELL_TYPE_MASK);
if (NewSize <= (ULONG)Size) {
//
// Found a big enough cell.
//
HvpComputeIndex(FoundCellIndex, Size);
if( Index == FoundCellIndex ) {
//
// and enlisted at the same index (we want to avoid fragmentation if possible!)
//
if (! HvMarkCellDirty(Hive, cellindex)) {
return HCELL_NIL;
}
HvpDelistFreeCell(Hive, cellindex, Type);
ASSERT(p->Size > 0);
ASSERT(NewSize <= (ULONG)p->Size);
return cellindex;
}
}
} else {
//
// used cell
//
Size = (ULONG)(p->Size * -1);
}
ASSERT( ((LONG)Size) >= 0);
p = (PHCELL)((PUCHAR)p + Size);
}
#ifdef CM_MAP_NO_READ
} except (EXCEPTION_EXECUTE_HANDLER) {
CmKdPrintEx((DPFLTR_CONFIG_ID,DPFLTR_ERROR_LEVEL,"HvpFindFreeCellInBin: exception thrown ehile faulting in data, code:%08lx\n", GetExceptionCode()));
return HCELL_NIL;
}
#endif //CM_MAP_NO_READ
//
// no free cell matching this size on this bin ; We did all this work for nothing!
//
CmKdPrintEx((DPFLTR_CONFIG_ID,CML_FREECELL,"[HvpFindFreeCellInBin] (Offset,Size) = (%lx,%lx) ==> No Match\n",BinOffset,Bin->Size));
return HCELL_NIL;
}
HCELL_INDEX
HvpScanForFreeCellInViewWindow(
PHHIVE Hive,
ULONG Index,
ULONG NewSize,
HSTORAGE_TYPE Type,
HCELL_INDEX FileOffsetStart
)
/*++
Routine Description:
Lookup for a free cell with the size NewSize in the CM_VIEW_SIZE window defined by
Vicinity.
If it doesn't find a free cell for the specifed index, tries with the
Arguments:
Hive - target hive.
Index - index in FreeDisplay (based on the free cell size)
NewSize - desired size
Type - storage type (Stable or Volatile)
Vicinity - defines the window; it is never HCELL_NIL !!!
Return Value:
A free cellindex with a size bigger than NewSize, or HCELL_NIL
Note:
Vicinity is a physical file offset at this point. we need to
convert it to a logical one prior to accessing the map
--*/
{
ULONG FileOffsetEnd;
HCELL_INDEX Cell;
PHMAP_ENTRY Me;
PHBIN Bin;
PFREE_HBIN FreeBin;
ULONG BinFileOffset;
ULONG BinSize;
PAGED_CODE();
FileOffsetEnd = FileOffsetStart + CM_VIEW_SIZE;
FileOffsetEnd -= HBLOCK_SIZE;
if( FileOffsetStart != 0 ) {
FileOffsetStart -= HBLOCK_SIZE;
}
if( FileOffsetEnd > Hive->Storage[Type].Length ) {
FileOffsetEnd = Hive->Storage[Type].Length;
}
CmKdPrintEx((DPFLTR_CONFIG_ID,CML_FREECELL,"\t[HvpScanForFreeCellInViewWindow] (Start,End) = (%lx,%lx) Size = %lx\n",FileOffsetStart,FileOffsetEnd,Hive->Storage[Type].Length));
//
// sanity ASSERT
//
ASSERT( FileOffsetStart < FileOffsetEnd );
//
// the caller already checked for this; remember, hints are for real!
//
ASSERT( !RtlAreBitsClear( &(Hive->Storage[Type].FreeDisplay[Index]),FileOffsetStart/HBLOCK_SIZE,(FileOffsetEnd - FileOffsetStart) / HBLOCK_SIZE) );
while( FileOffsetStart < FileOffsetEnd ) {
Cell = FileOffsetStart + (Type*HCELL_TYPE_MASK);
Me = HvpGetCellMap(Hive, Cell);
VALIDATE_CELL_MAP(__LINE__,Me,Hive,Cell);
//
// skip discarded bins
//
if(Me->BinAddress & HMAP_DISCARDABLE) {
FreeBin = (PFREE_HBIN)Me->BlockAddress;
if( FreeBin->FileOffset == FileOffsetStart ) {
FileOffsetStart += FreeBin->Size;
} else {
//
// the bin does not start in this window;
// skip to the next bin in this window
//
FileOffsetStart = FreeBin->FileOffset + FreeBin->Size;
}
continue;
}
if((Me->BinAddress & (HMAP_INVIEW|HMAP_INPAGEDPOOL)) == 0) {
//
// bin is not mapped, map it now!!!
// do not touch the view as we may iterate through
// the hole hive; this will keep the view for this window
// mapped, as we hold the registry lock exclusive
//
if( !NT_SUCCESS(CmpMapThisBin((PCMHIVE)Hive,Cell,FALSE)) ) {
//
// cannot map bin due to insufficient resources
//
return HCELL_NIL;
}
ASSERT( Me->BinAddress & HMAP_INVIEW );
}
Bin = (PHBIN)HBIN_BASE(Me->BinAddress);
#ifdef CM_MAP_NO_READ
//
// we need to protect against in-page-errors thrown by mm while faulting in data
//
try {
#endif //CM_MAP_NO_READ
BinFileOffset = Bin->FileOffset;
BinSize = Bin->Size;
#ifdef CM_MAP_NO_READ
} except (EXCEPTION_EXECUTE_HANDLER) {
CmKdPrintEx((DPFLTR_CONFIG_ID,DPFLTR_ERROR_LEVEL,"HvpScanForFreeCellInViewWindow: exception thrown while faulting in data, code:%08lx\n", GetExceptionCode()));
return HCELL_NIL;
}
#endif //CM_MAP_NO_READ
if( BinFileOffset == FileOffsetStart ) {
Cell = HvpFindFreeCellInBin(Hive,Index,NewSize,Type,Bin);
if( Cell != HCELL_NIL ) {
//found it!
return Cell;
}
FileOffsetStart += BinSize;
} else {
//
// bin does not start in this CM_VIEW_SIZE window; skip to the next bin in this window
//
FileOffsetStart = BinFileOffset + BinSize;
}
}
//
// no free cell matching this size on the CM_VIEW_SIZE window ; We did all this work for nothing!
//
CmKdPrintEx((DPFLTR_CONFIG_ID,CML_FREECELL,"[HvpScanForFreeCellInViewWindow] (Start,End) = (%lx,%lx) ==> No Match\n",FileOffsetStart,FileOffsetEnd));
return HCELL_NIL;
}
HCELL_INDEX
HvpFindFreeCellInThisViewWindow(
PHHIVE Hive,
ULONG Index,
ULONG NewSize,
HSTORAGE_TYPE Type,
HCELL_INDEX Vicinity
)
/*++
Routine Description:
Lookup for a free cell with the size NewSize in the window defined by
Vicinity.
If it doesn't find a free cell for the specifed index, tries with the
Arguments:
Hive - target hive.
Index - index in FreeDisplay (based on the free cell size)
NewSize - desired size
Type - storage type (Stable or Volatile)
Vicinity - defines the window; it is never HCELL_NIL !!!
Return Value:
A free cellindex with a size bigger than NewSize, or HCELL_NIL
Note:
Vicinity is a logical file offset at this point. This function
converts it to a physical one, and HvpScanForFindFreeCellInViewWindow
converts it back to logical prior to getting the cell map.
--*/
{
HCELL_INDEX Cell;
ULONG FileOffsetStart;
ULONG FileOffsetEnd;
ULONG VicinityViewOffset;
ULONG Summary;
ULONG Offset;
ULONG RunLength;
PAGED_CODE();
ASSERT( Vicinity != HCELL_NIL );
VicinityViewOffset = ((Vicinity&(~HCELL_TYPE_MASK)) + HBLOCK_SIZE) & (~(CM_VIEW_SIZE - 1));
FileOffsetStart = VicinityViewOffset & (~(CM_VIEW_SIZE - 1));
FileOffsetEnd = FileOffsetStart + CM_VIEW_SIZE;
if( FileOffsetEnd > (Hive->Storage[Type].Length + HBLOCK_SIZE) ) {
FileOffsetEnd = Hive->Storage[Type].Length + HBLOCK_SIZE;
}
CmKdPrintEx((DPFLTR_CONFIG_ID,CML_FREECELL,"[HvpFindFreeCellInThisViewWindow] Vicinity = %lx (Start,End) = (%lx,%lx) Size = %lx\n",Vicinity,FileOffsetStart,FileOffsetEnd,Hive->Storage[Type].Length));
//
// sanity assert
//
ASSERT( FileOffsetStart < FileOffsetEnd );
//
// at this point the offset is physical (file-oriented, i.e. it is
// translated with HBLOCK_SIZE; HvpScanForFreeCellInViewWindow will do the
// reverse computation to adjust the offset)
//
//
// Compute Summary vector of Display entries that are non null
//
Summary = Hive->Storage[Type].FreeSummary;
Summary = Summary & ~((1 << Index) - 1);
//
// We now have a summary of lists that are non-null and may
// contain entries large enough to satisfy the request.
// Iterate through the list and pull the first cell that is
// big enough. If no cells are big enough, advance to the
// next non-null list.
//
ASSERT(HHIVE_FREE_DISPLAY_SIZE == 24);
Offset = FileOffsetStart?(FileOffsetStart-HBLOCK_SIZE):0;
RunLength = FileOffsetEnd - FileOffsetStart;
if( FileOffsetStart == 0 ) {
//
// first run is one block shorter !
//
RunLength -= HBLOCK_SIZE;
}
Offset /= HBLOCK_SIZE;
RunLength /= HBLOCK_SIZE;
while (Summary != 0) {
if (Summary & 0xff) {
Index = CmpFindFirstSetRight[Summary & 0xff];
} else if (Summary & 0xff00) {
Index = CmpFindFirstSetRight[(Summary & 0xff00) >> 8] + 8;
} else {
ASSERT(Summary & 0xff0000);
Index = CmpFindFirstSetRight[(Summary & 0xff0000) >> 16] + 16;
}
//
// we go down this path only if we have any hints
//
if( !RtlAreBitsClear( &(Hive->Storage[Type].FreeDisplay[Index]),Offset,RunLength) ) {
//
// we have a reason to scan this view
//
Cell = HvpScanForFreeCellInViewWindow(Hive,Index,NewSize,Type,VicinityViewOffset);
if( Cell != HCELL_NIL ) {
// found it
return Cell;
}
//
// if we got here, the hints are invalid
//
CmKdPrintEx((DPFLTR_CONFIG_ID,CML_FREECELL,"[HvpFindFreeCellInThisViewWindow] (Start,End) = (%lx,%lx) Offset = %lx RunLength = %lx\n",FileOffsetStart,FileOffsetEnd,Offset,RunLength));
}
//
// No suitable cell was found of this size.
// Clear the bit in the summary and try the
// next biggest size
//
ASSERT(Summary & (1 << Index));
Summary = Summary & ~(1 << Index);
}
return HCELL_NIL;
}
HCELL_INDEX
HvpFindFreeCell(
PHHIVE Hive,
ULONG Index,
ULONG NewSize,
HSTORAGE_TYPE Type,
HCELL_INDEX Vicinity
)
/*++
Routine Description:
Lookup for a free cell. First try is in the CM_VIEW_SIZE window defined
by Vicinity. If no free cell is found in this window (or vicinity
if NIL), entire hive is searched (window by window).
Arguments:
Hive - target hive.
Index - index in FreeDisplay (based on the free cell size)
NewSize - desired size
Type - storage type (Stable or Volatile)
Vicinity - defines the window.
Return Value:
A free cellindex with a size bigger than NewSize, or HCELL_NIL
Optimization:
When Vicinity is HCELL_NIL or if a cell is not found in the same window
as the vicinity, we don't really care where the cell gets allocated.
So, rather than iterating the whole hive, is a good ideea to search first
in the pinned view list, then in the mapped view list, and at the end
in the rest of unmapped views.
DRAGOS: This is not finished: need to determine whether we need it or not
--*/
{
HCELL_INDEX Cell = HCELL_NIL;
ULONG FileOffset = 0;
PCMHIVE CmHive;
/*
PCMHIVE CmHive;
PCM_VIEW_OF_FILE CmView;
USHORT NrViews;
*/
PAGED_CODE();
CmHive = (PCMHIVE)CONTAINING_RECORD(Hive, CMHIVE, Hive);
#if DBG
{
UNICODE_STRING HiveName;
RtlInitUnicodeString(&HiveName, (PCWSTR)Hive->BaseBlock->FileName);
CmKdPrintEx((DPFLTR_CONFIG_ID,CML_FREECELL,"[HvpFindFreeCell] CellSize = %lu Vicinity = %lx :: Hive (%p) (%.*S) ...",NewSize,Vicinity,Hive,HiveName.Length / sizeof(WCHAR),HiveName.Buffer));
}
#endif
//
// Vicinity should have the same storage as the new cell !
//
ASSERT( (Vicinity == HCELL_NIL) || (HvGetCellType(Vicinity) == (ULONG)Type) );
//
// we have the lock exclusive or nobody is operating inside this hive
//
//ASSERT_CM_LOCK_OWNED_EXCLUSIVE();
ASSERT_CM_EXCLUSIVE_HIVE_ACCESS(Hive);
if( (Vicinity != HCELL_NIL) && (CmHive->GrowOnlyMode == FALSE) ) {
//
// try first in this window
//
Cell = HvpFindFreeCellInThisViewWindow(Hive,Index,NewSize,Type,Vicinity);
}
if( Cell != HCELL_NIL ) {
//
// found it!!!
//
CmKdPrintEx((DPFLTR_CONFIG_ID,CML_FREECELL,"found cell %lx \n",Cell));
return Cell;
}
/*
//
// Optimization:
// Step 1 : Search first in the pinned views
//
CmHive = (PCMHIVE)CONTAINING_RECORD(Hive, CMHIVE, Hive);
//
// iterate through the pinned views
//
CmView = (PCM_VIEW_OF_FILE)CmHive->PinViewListHead.Flink;
for(NrViews = CmHive->PinnedViews;NrViews;NrViews--) {
CmView = CONTAINING_RECORD( CmView,
CM_VIEW_OF_FILE,
PinViewList);
ASSERT( (CmView->FileOffset + CmView->Size) != 0 && (CmView->ViewAddress != 0));
FileOffset = CmView->FileOffset;
// adjust the offset
if( FileOffset > 0 ) {
FileOffset -= HBLOCK_SIZE;
}
//
// search in this window
//
Cell = FileOffset + (Type*HCELL_TYPE_MASK);
Cell = HvpFindFreeCellIn256kWindow(Hive,Index,NewSize,Type,Cell);
if( Cell != HCELL_NIL ) {
//
// found it!
//
CmKdPrintEx((DPFLTR_CONFIG_ID,CML_FREECELL,"found cell %lx \n",Cell));
return Cell;
}
CmView = (PCM_VIEW_OF_FILE)CmView->PinViewList.Flink;
}
//
// Step 2: Search in the mapped views
//
CmView = (PCM_VIEW_OF_FILE)CmHive->LRUViewListHead.Flink;
for(NrViews = CmHive->MappedViews;NrViews;NrViews--) {
CmView = CONTAINING_RECORD( CmView,
CM_VIEW_OF_FILE,
LRUViewList);
ASSERT( (CmView->FileOffset + CmView->Size) != 0 && (CmView->ViewAddress != 0));
FileOffset = CmView->FileOffset;
// adjust the offset
if( FileOffset > 0 ) {
FileOffset -= HBLOCK_SIZE;
}
//
// search in this window
//
Cell = FileOffset + (Type*HCELL_TYPE_MASK);
Cell = HvpFindFreeCellIn256kWindow(Hive,Index,NewSize,Type,Cell);
if( Cell != HCELL_NIL ) {
//
// found it!
//
CmKdPrintEx((DPFLTR_CONFIG_ID,CML_FREECELL,"found cell %lx \n",Cell));
return Cell;
}
CmView = (PCM_VIEW_OF_FILE)CmView->LRUViewList.Flink;
}
FileOffset = 0;
*/
//
// bad luck!; we did not found it in this window.
// We have to search the entire hive
//
while( FileOffset < Hive->Storage[Type].Length ) {
//
// don't search again in the vicinity window
// we already did it once
//
if( ( ((CmHive->GrowOnlyMode == FALSE) || (Type == Volatile)) &&
((Vicinity == HCELL_NIL) || (HvpCheckViewBoundary(FileOffset,Vicinity&(~HCELL_TYPE_MASK)) == FALSE)) ) ||
( (CmHive->GrowOnlyMode == TRUE) && (FileOffset >= CmHive->GrowOffset) )
) {
//
// search in this window
//
Cell = FileOffset + (Type*HCELL_TYPE_MASK);
Cell = HvpFindFreeCellInThisViewWindow(Hive,Index,NewSize,Type,Cell);
if( Cell != HCELL_NIL ) {
//
// found it!
//
CmKdPrintEx((DPFLTR_CONFIG_ID,CML_FREECELL,"found cell %lx \n",Cell));
return Cell;
}
}
//
// advance to the new window
//
if( FileOffset == 0) {
// account for the base block
FileOffset += (CM_VIEW_SIZE - HBLOCK_SIZE);
} else {
FileOffset += CM_VIEW_SIZE;
}
}
CmKdPrintEx((DPFLTR_CONFIG_ID,CML_FREECELL,"No cell found.\n"));
return HCELL_NIL;
}
BOOLEAN
HvpCheckViewBoundary(
IN ULONG Start,
IN ULONG End
)
/*++
Routine Description:
Checks if addresses are in the same CM_VIEW_SIZE boundary.
We may convert this function to a macro for performance
reasons
Arguments:
Start - starting address
End - ending address
Return Value:
TRUE - yes, addresses are in the same view
FALSE - no, addresses are NOT in the same view
--*/
{
PAGED_CODE();
//
// account for the header
//
Start += HBLOCK_SIZE;
End += HBLOCK_SIZE;
//
// truncate to the CM_VIEW_SIZE segment
//
Start &= (~(CM_VIEW_SIZE - 1));
End &= (~(CM_VIEW_SIZE - 1));
if( Start != End ){
return FALSE;
}
return TRUE;
}