HDFS-7242. Code improvement for FSN#checkUnreadableBySuperuser. (Contributed by Yi Liu)

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -399,6 +399,9 @@ Release 2.7.0 - UNRELEASED
     HDFS-7190. Bad use of Preconditions in startFileInternal().
     (Dawson Choong via wheat9)
 
+    HDFS-7242. Code improvement for FSN#checkUnreadableBySuperuser.
+    (Yi Liu via vinayakumarb)
+
 Release 2.6.0 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java

@@ -6412,10 +6412,10 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
   private void checkUnreadableBySuperuser(FSPermissionChecker pc,
       INode inode, int snapshotId)
       throws IOException {
-    for (XAttr xattr : dir.getXAttrs(inode, snapshotId)) {
-      if (XAttrHelper.getPrefixName(xattr).
-          equals(SECURITY_XATTR_UNREADABLE_BY_SUPERUSER)) {
-        if (pc.isSuperUser()) {
+    if (pc.isSuperUser()) {
+      for (XAttr xattr : dir.getXAttrs(inode, snapshotId)) {
+        if (XAttrHelper.getPrefixName(xattr).
+            equals(SECURITY_XATTR_UNREADABLE_BY_SUPERUSER)) {
           throw new AccessControlException("Access is denied for " +
               pc.getUser() + " since the superuser is not allowed to " +
               "perform this operation.");