restore Store.readSegmentsInfo(IndexCommit, Directory)

Author: tlrx

server/src/main/java/org/elasticsearch/index/store/Store.java

@@ -206,13 +206,33 @@ public Directory directory() {
  public SegmentInfos readLastCommittedSegmentsInfo() throws IOException {
  failIfCorrupted();
  try {
- return Lucene.readSegmentInfos(directory);
+ return readSegmentsInfo(null, directory());
  } catch (CorruptIndexException | IndexFormatTooOldException | IndexFormatTooNewException ex) {
  markStoreCorrupted(ex);
  throw ex;
  }
  }
 
+ /**
+ * Returns the segments info for the given commit or for the latest commit if the given commit is <code>null</code>
+ *
+ * @throws IOException if the index is corrupted or the segments file is not present
+ */
+ private static SegmentInfos readSegmentsInfo(IndexCommit commit, Directory directory) throws IOException {
+ assert commit == null || commit.getDirectory() == directory;
+ try {
+ return commit == null ? Lucene.readSegmentInfos(directory) : Lucene.readSegmentInfos(commit);
+ } catch (EOFException eof) {
+ // TODO this should be caught by lucene - EOF is almost certainly an index corruption
+ throw new CorruptIndexException("Read past EOF while reading segment infos", "commit(" + commit + ")", eof);
+ } catch (IOException exception) {
+ throw exception; // IOExceptions like too many open files are not necessarily a corruption - just bubble it up
+ } catch (Exception ex) {
+ throw new CorruptIndexException("Hit unexpected exception while reading segment infos", "commit(" + commit + ")", ex);
+ }
+
+ }
+
  final void ensureOpen() {
  if (this.refCounter.refCount() <= 0) {
  throw new AlreadyClosedException("store is already closed");
@@ -804,21 +824,7 @@ static MetadataSnapshot loadFromIndexCommit(@Nullable IndexCommit commit, Direct
  final Map<String, StoreFileMetadata> metadataByFile = new HashMap<>();
  final Map<String, String> commitUserData;
  try {
- assert commit == null || commit.getDirectory() == directory;
- final SegmentInfos segmentCommitInfos;
- try {
- if (commit == null) {
- segmentCommitInfos = Lucene.readSegmentInfos(directory);
- } else {
- segmentCommitInfos = Lucene.readSegmentInfos(commit);
- }
- } catch (EOFException eof) {
- // TODO this should be caught by lucene - EOF is almost certainly an index corruption
- throw new CorruptIndexException("Read past EOF while reading segment infos", "commit(" + commit + ")", eof);
- } catch (Exception ex) {
- throw new CorruptIndexException("Hit unexpected exception while reading segment infos", "commit(" + commit + ")", ex);
- }
-
+ final SegmentInfos segmentCommitInfos = readSegmentsInfo(commit, directory);
  numDocs = Lucene.getNumDocs(segmentCommitInfos);
  commitUserData = Map.copyOf(segmentCommitInfos.getUserData());
  // we don't know which version was used to write so we take the max version.