HDFS-11152. Start erasure coding policy ID number from 1 instead of 0 to void potential unexpected errors. Contributed by SammiChen.

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/protocol/HdfsConstants.java

@@ -144,11 +144,11 @@ public final class HdfsConstants {
     ALL, LIVE, DEAD, DECOMMISSIONING, ENTERING_MAINTENANCE
   }
 
-  public static final byte RS_6_3_POLICY_ID = 0;
-  public static final byte RS_3_2_POLICY_ID = 1;
-  public static final byte RS_6_3_LEGACY_POLICY_ID = 2;
-  public static final byte XOR_2_1_POLICY_ID = 3;
-  public static final byte RS_10_4_POLICY_ID = 4;
+  public static final byte RS_6_3_POLICY_ID = 1;
+  public static final byte RS_3_2_POLICY_ID = 2;
+  public static final byte RS_6_3_LEGACY_POLICY_ID = 3;
+  public static final byte XOR_2_1_POLICY_ID = 4;
+  public static final byte RS_10_4_POLICY_ID = 5;
 
   /* Hidden constructor */
   protected HdfsConstants() {

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

@@ -342,6 +342,9 @@ public final class FSImageFormatPBINode {
       for (int i = 0; i < bp.size(); ++i) {
         BlockProto b = bp.get(i);
         if (isStriped) {
+          Preconditions.checkState(ecPolicy.getId() > 0,
+              "File with ID " + n.getId() +
+              " has an invalid erasure coding policy ID " + ecPolicy.getId());
           blocks[i] = new BlockInfoStriped(PBHelperClient.convert(b), ecPolicy);
         } else {
           blocks[i] = new BlockInfoContiguous(PBHelperClient.convert(b),