public void Extend()
{
ulong additionalDataLength = (ulong)(m_volume.BytesPerFileRecordSegment * ExtendGranularity);
ulong additionalBitmapLength = ExtendGranularity / 8;
// We calculate the maximum possible number of free cluster required
long numberOfClustersRequiredForData = (long)Math.Ceiling((double)additionalDataLength / m_volume.BytesPerCluster);
long numberOfClustersRequiredForBitmap = (long)Math.Ceiling((double)additionalBitmapLength / m_volume.BytesPerCluster);
if (numberOfClustersRequiredForData + numberOfClustersRequiredForBitmap > m_volume.NumberOfFreeClusters)
{
throw new DiskFullException();
}
// We have to extend the bitmap first because one of the constructor parameters is the size of the data.
// MFT Bitmap: ValidDataLength could be smaller than FileSize, however, we will later copy the value of ValidDataLength.
// to the MFT mirror, we have to make sure that the copy will not become stale after writing beyond the current ValidDataLength.
m_mftFile.Bitmap.ExtendBitmap(ExtendGranularity, true);
// MFT Data: ValidDataLength must be equal to FileSize.
// This will take care of the FileNameRecord and RootDirectory index as well.
// Note: The NTFS v5.1 driver does not bother updating the FileNameRecord.
m_mftFile.WriteData(m_mftFile.Data.Length, new byte[additionalDataLength]);
// Update the MFT mirror
MasterFileTable mftMirror = new MasterFileTable(m_volume, false, true);
// When the MFT has an attribute list, CHKDSK expects the mirror to contain the segment references from the MFT as-is.
FileRecordSegment mftRecordSegmentFromMirror = mftMirror.GetFileRecordSegment(MasterFileTableSegmentNumber);
mftRecordSegmentFromMirror.ImmediateAttributes.Clear();
mftRecordSegmentFromMirror.ImmediateAttributes.AddRange(m_mftFile.FileRecord.BaseSegment.ImmediateAttributes);
// CHKDSK seems to expect the mirror's NextAttributeInstance to be the same as the MFT.
mftRecordSegmentFromMirror.NextAttributeInstance = m_mftFile.FileRecord.BaseSegment.NextAttributeInstance;
mftMirror.UpdateFileRecordSegment(mftRecordSegmentFromMirror);
}
public override void Write(byte[] buffer, int offset, int count)
{
byte[] data = new byte[count];
Array.Copy(buffer, offset, data, 0, count);
m_file.WriteData((ulong)m_position, data);
m_position += count;
}
public override void Write(byte[] buffer, int offset, int count)
{
if (!CanWrite)
{
throw new AccessViolationException("Stream was not opened for write access");
}
byte[] data = new byte[count];
Array.Copy(buffer, offset, data, 0, count);
m_file.WriteData((ulong)m_position, data);
m_position += count;
}