HDFS-14323. Distcp fails in Hadoop 3.x when 2.x source webhdfs url has special characters in hdfs file path. Contributed by Srinivasu Majeti.

Signed-off-by: Wei-Chiu Chuang <weichiu@apache.org>

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/web/WebHdfsFileSystem.java

@@ -609,7 +609,13 @@ public class WebHdfsFileSystem extends FileSystem
       boolean pathAlreadyEncoded = false;
       try {
         fspathUriDecoded = URLDecoder.decode(fspathUri.getPath(), "UTF-8");
-        pathAlreadyEncoded = true;
+        //below condition check added as part of fixing HDFS-14323 to make
+        //sure pathAlreadyEncoded is not set in the case the input url does
+        //not have any encoded sequence already.This will help pulling data
+        //from 2.x hadoop cluster to 3.x using 3.x distcp client operation
+        if(!fspathUri.getPath().equals(fspathUriDecoded)) {
+          pathAlreadyEncoded = true;
+        }
       } catch (IllegalArgumentException ex) {
         LOG.trace("Cannot decode URL encoded file", ex);
       }