apache/hadoop · warning · XAttrNotFoundException

At least one of the attributes provided was not found.

Error message

At least one of the attributes provided was not found.

What it means

getXAttrs with a name list first filters the inode's xattrs down to what the caller may see (XAttrPermissionFilter). If nothing survives, because the file has no xattrs at all or only restricted-namespace entries the caller cannot read, filteredAll is empty and the request fails with XAttrNotFoundException instead of returning an empty list.

Solutions

Call fs.listXAttrs(path) first and request only names it returns; an empty list means none, handle as absent
Catch XAttrNotFoundException (an IOException subclass) and treat it as attribute-absent
Run with owner or superuser privileges if restricted-namespace xattrs are genuinely expected

Example fix

// before
byte[] v = fs.getXAttr(path, "user.mytag"); // throws on xattr-less file

// after
byte[] v = null;
if (fs.listXAttrs(path).contains("user.mytag")) {
  v = fs.getXAttr(path, "user.mytag");
}

Defensive patterns

Strategy: validation

Validate before calling

List<String> present = fs.listXAttrs(path);
if (!present.contains("user.mytag")) {
  return Optional.empty();
}
return Optional.of(fs.getXAttr(path, "user.mytag"));

Try / catch

try {
  return Optional.of(fs.getXAttr(path, name));
} catch (XAttrNotFoundException e) {
  return Optional.empty(); // attribute absent: not an error for optional metadata
}

Prevention

Treat xattrs as optional metadata: list first or catch not-found
Remember privileges filter raw/trusted/security namespaces out of the API view
Use the user. namespace for application metadata

When it happens

Trigger: fs.getXAttr(path, name) or the multi-name getXAttrs on a file with no visible xattrs; typical when probing raw./trusted./security. namespaces without the privileges that let those attributes pass the filter.

Common situations: Probing optional metadata markers that may or may not exist; non-privileged readers of files whose only xattrs live in restricted namespaces.

Related errors

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/413289e285abdee2. Report an issue: GitHub.

Appendix: source

Thrown at hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSDirXAttrOp.java:118

    checkXAttrsConfigFlag(fsd);
    final boolean isRawPath = FSDirectory.isReservedRawName(src);
    boolean getAll = xAttrs == null || xAttrs.isEmpty();
    if (!getAll) {
      XAttrPermissionFilter.checkPermissionForApi(pc, xAttrs, isRawPath);
    }
    final INodesInPath iip = fsd.resolvePath(pc, src, DirOp.READ);
    if (fsd.isPermissionEnabled()) {
      fsd.checkPathAccess(pc, iip, FsAction.READ);
    }
    List<XAttr> all = FSDirXAttrOp.getXAttrs(fsd, iip);
    List<XAttr> filteredAll = XAttrPermissionFilter.
        filterXAttrsForApi(pc, all, isRawPath);

    if (getAll) {
      return filteredAll;
    }
    if (filteredAll == null || filteredAll.isEmpty()) {
      throw new XAttrNotFoundException();
    }
    List<XAttr> toGet = Lists.newArrayListWithCapacity(xAttrs.size());
    for (XAttr xAttr : xAttrs) {
      boolean foundIt = false;
      for (XAttr a : filteredAll) {
        if (xAttr.getNameSpace() == a.getNameSpace() && xAttr.getName().equals(
            a.getName())) {
          toGet.add(a);
          foundIt = true;
          break;
        }
      }
      if (!foundIt) {
        throw new XAttrNotFoundException();
      }
    }
    return toGet;
  }

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