pigloadfuncwithfilename

@Override
public void prepareToRead(@SuppressWarnings("rawtypes") RecordReader reader, PigSplit split)
throws IOException {
    mSplit = split;
    in = reader;
}

//add something like this to your getNext()
if (mSplit != null) {
    FileSplit fs = (FileSplit) mSplit.getWrappedSplit();
    String fn = fs.getPath().toString();
    value = new Text(in.getCurrentValue() + "," + fn);
} else {
    value = (Text) in.getCurrentValue();
}