svn merge -c 1408488 FIXES: HADOOP-9022. Hadoop distcp tool fails to copy file if -m 0 specified (Jonathan Eagles vai bobby)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1408493 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -55,6 +55,9 @@ Release 0.23.5 - UNRELEASED
 
     HADOOP-8986. Server$Call object is never released after it is sent (bobby)
 
+    HADOOP-9022. Hadoop distcp tool fails to copy file if -m 0 specified
+    (Jonathan Eagles vai bobby)
+
 Release 0.23.4 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-tools/hadoop-distcp/src/main/java/org/apache/hadoop/tools/DistCpOptions.java

@@ -274,7 +274,7 @@ public class DistCpOptions {
    * @param maxMaps - Number of maps
    */
   public void setMaxMaps(int maxMaps) {
-    this.maxMaps = maxMaps;
+    this.maxMaps = Math.max(maxMaps, 1);
   }
 
   /** Get the map bandwidth in MB

hadoop-tools/hadoop-distcp/src/test/java/org/apache/hadoop/tools/TestOptionsParser.java

@@ -275,6 +275,13 @@ public class TestOptionsParser {
         "hdfs://localhost:8020/target/"});
     Assert.assertEquals(options.getMaxMaps(), 1);
 
+    options = OptionsParser.parse(new String[] {
+        "-m",
+        "0",
+        "hdfs://localhost:8020/source/first",
+        "hdfs://localhost:8020/target/"});
+    Assert.assertEquals(options.getMaxMaps(), 1);
+
     try {
       OptionsParser.parse(new String[] {
           "-m",