return FreeClusters;
}
+/**
+* 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;
+ PCHAR BitmapData;
+ ULONGLONG FreeClusters = 0;
+ ULONG Read = 0;
+ RTL_BITMAP Bitmap;
+
+ DPRINT1("NtfsAllocateClusters(%p, %lu, %lu, %p)\n", DeviceExt, DesiredClusters, FirstDesiredCluster, FirstAssignedCluster, AssignedClusters);
+
+ BitmapRecord = ExAllocatePoolWithTag(NonPagedPool,
+ DeviceExt->NtfsInfo.BytesPerFileRecord,
+ TAG_NTFS);
+ if (BitmapRecord == NULL)
+ {
+ return 0;
+ }
+
+ Status = ReadFileRecord(DeviceExt, NTFS_FILE_BITMAP, BitmapRecord);
+ if (!NT_SUCCESS(Status))
+ {
+ ExFreePoolWithTag(BitmapRecord, TAG_NTFS);
+ return 0;
+ }
+
+ Status = FindAttribute(DeviceExt, BitmapRecord, AttributeData, L"", 0, &DataContext, NULL);
+ if (!NT_SUCCESS(Status))
+ {
+ ExFreePoolWithTag(BitmapRecord, TAG_NTFS);
+ return 0;
+ }
+
+ BitmapDataSize = AttributeDataLength(&DataContext->Record);
+ 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);
+ ExFreePoolWithTag(BitmapRecord, TAG_NTFS);
+ return 0;
+ }
+
+ 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, Read, (PCHAR)((ULONG_PTR)BitmapData + Read), (ULONG)BitmapDataSize);
+
+ RtlInitializeBitMap(&Bitmap, (PULONG)BitmapData, DeviceExt->NtfsInfo.ClusterCount);
+ FreeClusters = RtlNumberOfClearBits(&Bitmap);
+
+ if (FreeClusters >= DesiredClusters)
+ {
+ // TODO: Observe MFT reservation zone
+
+ // Can we get one contiguous run?
+ ULONG AssignedRun = RtlFindClearBitsAndSet(&Bitmap, DesiredClusters, FirstDesiredCluster);
+ ULONG LengthWritten;
+
+ 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);
+ }
+ else
+ Status = STATUS_DISK_FULL;
+
+
+ ReleaseAttributeContext(DataContext);
+
+ ExFreePoolWithTag(BitmapData, TAG_NTFS);
+ ExFreePoolWithTag(BitmapRecord, TAG_NTFS);
+
+ return Status;
+}
+
static
NTSTATUS
NtfsGetFsVolumeInformation(PDEVICE_OBJECT DeviceObject,