apache/hadoop · error · IOException

Cannot specify the same XAttr to be set more than once

Error message

Cannot specify the same XAttr to be set more than once

What it means

Error "Cannot specify the same XAttr to be set more than once" thrown in apache/hadoop.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSDirXAttrOp.java:330

        throw new IOException("Can only set '" +
            XATTR_SNAPSHOT_DELETED + "' on a snapshot root.");
      }
    }

    XAttrStorage.updateINodeXAttrs(inode, newXAttrs, iip.getLatestSnapshotId());
    return inode;
  }

  static List<XAttr> setINodeXAttrs(
      FSDirectory fsd, final List<XAttr> existingXAttrs,
      final List<XAttr> toSet, final EnumSet<XAttrSetFlag> flag)
      throws IOException {
    // Check for duplicate XAttrs in toSet
    // We need to use a custom comparator, so using a HashSet is not suitable
    for (int i = 0; i < toSet.size(); i++) {
      for (int j = i + 1; j < toSet.size(); j++) {
        if (toSet.get(i).equalsIgnoreValue(toSet.get(j))) {
          throw new IOException("Cannot specify the same XAttr to be set " +
              "more than once");
        }
      }
    }

    // Count the current number of user-visible XAttrs for limit checking
    int userVisibleXAttrsNum = 0; // Number of user visible xAttrs

    // The XAttr list is copied to an exactly-sized array when it's stored,
    // so there's no need to size it precisely here.
    int newSize = (existingXAttrs != null) ? existingXAttrs.size() : 0;
    newSize += toSet.size();
    List<XAttr> xAttrs = Lists.newArrayListWithCapacity(newSize);

    // Check if the XAttr already exists to validate with the provided flag
    for (XAttr xAttr: toSet) {
      boolean exist = false;
      if (existingXAttrs != null) {

View on GitHub (pinned to 2add963021)

Solutions

1. Pass each XAttr name only once per setXAttrs call; remove duplicates from the request.

When it happens

Trigger: Calling setXAttrs with the same XAttr name appearing more than once in the list.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/943118c175be43a8. Report an issue: GitHub.