apache/hadoop · error · IOException

Found a block string when in state: {}

Error message

Found a block string when in state: {}

What it means

Error "Found a block string when in state: {}" thrown in apache/hadoop.

Source

Thrown at hadoop-tools/hadoop-dynamometer/hadoop-dynamometer-blockgen/src/main/java/org/apache/hadoop/tools/dynamometer/blockgenerator/XMLParser.java:101

      transitionTo(State.INODE);
    }
    if (line.contains("<type>FILE</type>")) {
      transitionTo(State.FILE);
    }
    List<String> replicationStrings = valuesFromXMLString(line, "replication");
    if (!replicationStrings.isEmpty()) {
      if (replicationStrings.size() > 1) {
        throw new IOException(String.format("Found %s replication strings",
            replicationStrings.size()));
      }
      transitionTo(State.FILE_WITH_REPLICATION);
      currentReplication = Short.parseShort(replicationStrings.get(0));
    }
    Matcher blockMatcher = BLOCK_PATTERN.matcher(line);
    List<BlockInfo> blockInfos = new ArrayList<>();
    while (blockMatcher.find()) {
      if (currentState != State.FILE_WITH_REPLICATION) {
        throw new IOException(
            "Found a block string when in state: " + currentState);
      }
      long id = Long.parseLong(blockMatcher.group(1));
      long gs = Long.parseLong(blockMatcher.group(2));
      long size = Long.parseLong(blockMatcher.group(3));
      blockInfos.add(new BlockInfo(id, gs, size, currentReplication));
    }
    if (line.contains("</inode>")) {
      transitionTo(State.INODE_SECTION);
    }
    if (line.contains("</INodeSection>")) {
      transitionTo(State.DEFAULT);
    }
    return blockInfos;
  }

  /**
   * Attempt to transition to another state.

View on GitHub (pinned to 2add963021)

Solutions

1. Regenerate the fsimage XML input; the parser hit a block element while in the wrong parser state.
2. Do not edit the fsimage XML by hand; regenerate it with hdfs oiv.

When it happens

Trigger: The XMLParser reads a block string token while the parser state machine is in an unexpected state, typically caused by a corrupted or hand-edited fsimage XML file fed to the dynamometer block generator.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/75997d0d0d4977c9. Report an issue: GitHub.