public FileRecord AllocateRecord(FileRecordFlags flags, bool isMft)
{
long index;
if (isMft)
{
// Have to take a lot of care extending the MFT itself, to ensure we never end up unable to
// bootstrap the file system via the MFT itself - hence why special records are reserved
// for MFT's own MFT record overflow.
for (int i = 15; i > 11; --i)
{
FileRecord r = GetRecord(i, false);
if (r.BaseFile.SequenceNumber == 0)
{
r.Reset();
r.Flags |= FileRecordFlags.InUse;
WriteRecord(r);
return(r);
}
}
throw new IOException("MFT too fragmented - unable to allocate MFT overflow record");
}
else
{
index = _bitmap.AllocateFirstAvailable(FirstAvailableMftIndex);
}
if (index * _recordLength >= _recordStream.Length)
{
// Note: 64 is significant, since bitmap extends by 8 bytes (=64 bits) at a time.
long newEndIndex = Utilities.RoundUp(index + 1, 64);
_recordStream.SetLength(newEndIndex * _recordLength);
for (long i = index; i < newEndIndex; ++i)
{
FileRecord record = new FileRecord(_bytesPerSector, _recordLength, (uint)i);
WriteRecord(record);
}
}
FileRecord newRecord = GetRecord(index, true);
newRecord.ReInitialize(_bytesPerSector, _recordLength, (uint)index);
_recordCache[index] = newRecord;
newRecord.Flags = FileRecordFlags.InUse | flags;
WriteRecord(newRecord);
_self.UpdateRecordInMft();
return(newRecord);
}
internal IndexBlock AllocateBlock(IndexEntry parentEntry)
{
if (_indexStream == null)
{
_file.CreateStream(AttributeType.IndexAllocation, _name);
_indexStream = _file.OpenStream(AttributeType.IndexAllocation, _name, FileAccess.ReadWrite);
}
if (_indexBitmap == null)
{
_file.CreateStream(AttributeType.Bitmap, _name);
_indexBitmap = new Bitmap(_file.OpenStream(AttributeType.Bitmap, _name, FileAccess.ReadWrite), long.MaxValue);
}
long idx = _indexBitmap.AllocateFirstAvailable(0);
parentEntry.ChildrenVirtualCluster = idx * Utilities.Ceil(_bpb.IndexBufferSize, _bpb.SectorsPerCluster * _bpb.BytesPerSector);
parentEntry.Flags |= IndexEntryFlags.Node;
IndexBlock block = IndexBlock.Initialize(this, false, parentEntry, _bpb);
_blockCache[parentEntry.ChildrenVirtualCluster] = block;
return(block);
}
