HDFS-6924. Add new RAM_DISK storage type. (Arpit Agarwal)

Conflicts:
	hadoop-hdfs-project/hadoop-hdfs/CHANGES-HDFS-6581.txt
	hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/StorageType.java
	hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocolPB/PBHelper.java
	hadoop-hdfs-project/hadoop-hdfs/src/main/proto/hdfs.proto

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/StorageType.java

@@ -33,7 +33,8 @@ import org.apache.hadoop.classification.InterfaceStability;
 public enum StorageType {
   DISK,
   SSD,
-  ARCHIVE;
+  ARCHIVE,
+  RAM_DISK;
 
   public static final StorageType DEFAULT = DISK;
   

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocolPB/PBHelper.java

@@ -1785,6 +1785,8 @@ public class PBHelper {
       return StorageTypeProto.SSD;
     case ARCHIVE:
       return StorageTypeProto.ARCHIVE;
+    case RAM_DISK:
+      return StorageTypeProto.RAM_DISK;
     default:
       throw new IllegalStateException(
           "BUG: StorageType not found, type=" + type);
@@ -1815,6 +1817,8 @@ public class PBHelper {
         return StorageType.SSD;
       case ARCHIVE:
         return StorageType.ARCHIVE;
+      case RAM_DISK:
+        return StorageType.RAM_DISK;
       default:
         throw new IllegalStateException(
             "BUG: StorageTypeProto not found, type=" + type);

hadoop-hdfs-project/hadoop-hdfs/src/main/proto/hdfs.proto

@@ -159,6 +159,7 @@ enum StorageTypeProto {
   DISK = 1;
   SSD = 2;
   ARCHIVE = 3;
+  RAM_DISK = 4;
 }
 
 /**
@@ -305,7 +306,6 @@ message HdfsFileStatusProto {
   // Optional field for fileId
   optional uint64 fileId = 13 [default = 0]; // default as an invalid id
   optional int32 childrenNum = 14 [default = -1];
-
   // Optional field for file encryption
   optional FileEncryptionInfoProto fileEncryptionInfo = 15;
 

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/protocolPB/TestPBHelper.java

@@ -448,13 +448,16 @@ public class TestPBHelper {
         DFSTestUtil.getLocalDatanodeInfo("127.0.0.1", "h2",
             AdminStates.DECOMMISSIONED),
         DFSTestUtil.getLocalDatanodeInfo("127.0.0.1", "h3", 
-            AdminStates.NORMAL)
+            AdminStates.NORMAL),
+        DFSTestUtil.getLocalDatanodeInfo("127.0.0.1", "h4",
+            AdminStates.NORMAL),
     };
-    String[] storageIDs = {"s1", "s2", "s3"};
+    String[] storageIDs = {"s1", "s2", "s3", "s4"};
     StorageType[] media = {
         StorageType.DISK,
         StorageType.SSD,
-        StorageType.DISK
+        StorageType.DISK,
+        StorageType.RAM_DISK
     };
     LocatedBlock lb = new LocatedBlock(
         new ExtendedBlock("bp12", 12345, 10, 53),

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/TestDataDirs.java

@@ -44,10 +44,11 @@ public class TestDataDirs {
     File dir1 = new File("/dir1");
     File dir2 = new File("/dir2");
     File dir3 = new File("/dir3");
+    File dir4 = new File("/dir4");
 
     // Verify that a valid string is correctly parsed, and that storage
     // type is not case-sensitive
-    String locations1 = "[disk]/dir0,[DISK]/dir1,[sSd]/dir2,[disK]/dir3";
+    String locations1 = "[disk]/dir0,[DISK]/dir1,[sSd]/dir2,[disK]/dir3,[ram_disk]/dir4";
     conf.set(DFS_DATANODE_DATA_DIR_KEY, locations1);
     locations = DataNode.getStorageLocations(conf);
     assertThat(locations.size(), is(4));
@@ -59,6 +60,8 @@ public class TestDataDirs {
     assertThat(locations.get(2).getUri(), is(dir2.toURI()));
     assertThat(locations.get(3).getStorageType(), is(StorageType.DISK));
     assertThat(locations.get(3).getUri(), is(dir3.toURI()));
+    assertThat(locations.get(4).getStorageType(), is(StorageType.RAM_DISK));
+    assertThat(locations.get(4).getUri(), is(dir4.toURI()));
 
     // Verify that an unrecognized storage type result in an exception.
     String locations2 = "[BadMediaType]/dir0,[ssd]/dir1,[disk]/dir2";