通过 IndexWriter.UpdateDocument 更新文档在 IndexWriter.Commit 提交时报错 "invalid docCount"

Lucene.Net.Index.CorruptIndexException: invalid docCount: 2 maxDoc: 1 (resource=MMapIndexInput(path="/zzk/index/blogpost/_afj.cfs") [slice=_afj_Lucene41_0.tim])
   at Lucene.Net.Codecs.BlockTreeTermsReader..ctor(Directory dir, FieldInfos fieldInfos, SegmentInfo info, PostingsReaderBase postingsReader, IOContext ioContext, String segmentSuffix, Int32 indexDivisor)
   at Lucene.Net.Codecs.Lucene41.Lucene41PostingsFormat.FieldsProducer(SegmentReadState state)
   at Lucene.Net.Codecs.PerField.PerFieldPostingsFormat.FieldsReader..ctor(SegmentReadState readState)
   at Lucene.Net.Index.SegmentCoreReaders..ctor(SegmentReader owner, Directory dir, SegmentCommitInfo si, IOContext context, Int32 termsIndexDivisor)
   at Lucene.Net.Index.SegmentReader..ctor(SegmentCommitInfo si, Int32 termInfosIndexDivisor, IOContext context)
   at Lucene.Net.Index.ReadersAndUpdates.GetReader(IOContext context)
   at Lucene.Net.Index.BufferedUpdatesStream.ApplyDeletesAndUpdates(ReaderPool readerPool, IList`1 infos)
   at Lucene.Net.Index.IndexWriter.ApplyAllDeletesAndUpdates()
   at Lucene.Net.Index.IndexWriter.MaybeApplyDeletes(Boolean applyAllDeletes)
   at Lucene.Net.Index.IndexWriter.PrepareCommitInternal()
   at Lucene.Net.Index.IndexWriter.CommitInternal()

请问如何解决？