/**
* NtfsAllocateClusters
* Allocates a run of clusters. The run allocated might be smaller than DesiredClusters.
*/
NTSTATUS
NtfsAllocateClusters(PDEVICE_EXTENSION DeviceExt,
ULONG FirstDesiredCluster,
ULONG DesiredClusters,
PULONG FirstAssignedCluster,
PULONG AssignedClusters)
{
NTSTATUS Status;
PFILE_RECORD_HEADER BitmapRecord;
PNTFS_ATTR_CONTEXT DataContext;
ULONGLONG BitmapDataSize;
PUCHAR BitmapData;
ULONGLONG FreeClusters = 0;
RTL_BITMAP Bitmap;
ULONG AssignedRun;
ULONG LengthWritten;
DPRINT1("NtfsAllocateClusters(%p, %lu, %lu, %p, %p)\n", DeviceExt, FirstDesiredCluster, DesiredClusters, FirstAssignedCluster, AssignedClusters);
BitmapRecord = ExAllocateFromNPagedLookasideList(&DeviceExt->FileRecLookasideList);
if (BitmapRecord == NULL)
{
return STATUS_INSUFFICIENT_RESOURCES;
}
Status = ReadFileRecord(DeviceExt, NTFS_FILE_BITMAP, BitmapRecord);
if (!NT_SUCCESS(Status))
{
ExFreeToNPagedLookasideList(&DeviceExt->FileRecLookasideList, BitmapRecord);
return Status;
}
Status = FindAttribute(DeviceExt, BitmapRecord, AttributeData, L"", 0, &DataContext, NULL);
if (!NT_SUCCESS(Status))
{
ExFreeToNPagedLookasideList(&DeviceExt->FileRecLookasideList, BitmapRecord);
return Status;
}
BitmapDataSize = AttributeDataLength(DataContext->pRecord);
BitmapDataSize = min(BitmapDataSize, 0xffffffff);
ASSERT((BitmapDataSize * 8) >= DeviceExt->NtfsInfo.ClusterCount);
BitmapData = ExAllocatePoolWithTag(NonPagedPool, ROUND_UP(BitmapDataSize, DeviceExt->NtfsInfo.BytesPerSector), TAG_NTFS);
if (BitmapData == NULL)
{
ReleaseAttributeContext(DataContext);
ExFreeToNPagedLookasideList(&DeviceExt->FileRecLookasideList, BitmapRecord);
return STATUS_INSUFFICIENT_RESOURCES;
}
DPRINT1("Total clusters: %I64x\n", DeviceExt->NtfsInfo.ClusterCount);
DPRINT1("Total clusters in bitmap: %I64x\n", BitmapDataSize * 8);
DPRINT1("Diff in size: %I64d B\n", ((BitmapDataSize * 8) - DeviceExt->NtfsInfo.ClusterCount) * DeviceExt->NtfsInfo.SectorsPerCluster * DeviceExt->NtfsInfo.BytesPerSector);
ReadAttribute(DeviceExt, DataContext, 0, (PCHAR)BitmapData, (ULONG)BitmapDataSize);
RtlInitializeBitMap(&Bitmap, (PULONG)BitmapData, DeviceExt->NtfsInfo.ClusterCount);
FreeClusters = RtlNumberOfClearBits(&Bitmap);
if (FreeClusters < DesiredClusters)
{
ReleaseAttributeContext(DataContext);
ExFreePoolWithTag(BitmapData, TAG_NTFS);
ExFreeToNPagedLookasideList(&DeviceExt->FileRecLookasideList, BitmapRecord);
return STATUS_DISK_FULL;
}
// TODO: Observe MFT reservation zone
// Can we get one contiguous run?
AssignedRun = RtlFindClearBitsAndSet(&Bitmap, DesiredClusters, FirstDesiredCluster);
if (AssignedRun != 0xFFFFFFFF)
{
*FirstAssignedCluster = AssignedRun;
*AssignedClusters = DesiredClusters;
}
else
{
// we can't get one contiguous run
*AssignedClusters = RtlFindNextForwardRunClear(&Bitmap, FirstDesiredCluster, FirstAssignedCluster);
if (*AssignedClusters == 0)
{
// we couldn't find any runs starting at DesiredFirstCluster
*AssignedClusters = RtlFindLongestRunClear(&Bitmap, FirstAssignedCluster);
}
}
Status = WriteAttribute(DeviceExt, DataContext, 0, BitmapData, (ULONG)BitmapDataSize, &LengthWritten, BitmapRecord);
ReleaseAttributeContext(DataContext);
ExFreePoolWithTag(BitmapData, TAG_NTFS);
ExFreeToNPagedLookasideList(&DeviceExt->FileRecLookasideList, BitmapRecord);
return Status;
}
ULONG NtdllBitmap::FindLongestRunClear( PULONG starting_index )
{
assert(RtlFindLongestRunClear != NULL);
return RtlFindLongestRunClear(this, starting_index);
}
