diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 9ee3bb8e71..4cb6dd8db6 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -62,6 +62,9 @@ Trunk (unreleased changes)
 
     HDFS-3016. Security in unit tests. (Jaimin Jetly via jitendra)
 
+    HDFS-3014. FSEditLogOp and its subclasses should have toString() method.
+    (Sho Shimauchi via atm)
+
   OPTIMIZATIONS
 
     HDFS-2477. Optimize computing the diff between a block report and the
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSEditLogOp.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSEditLogOp.java
index 61b4ef8a41..f075770c33 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSEditLogOp.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSEditLogOp.java
@@ -19,6 +19,7 @@
 
 import java.util.zip.CheckedInputStream;
 import java.util.zip.Checksum;
+import java.util.Arrays;
 import java.util.EnumMap;
 
 import org.apache.hadoop.fs.ChecksumException;
@@ -305,6 +306,36 @@ private static Block[] readBlocks(
       }
       return blocks;
     }
+
+    public String stringifyMembers() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("[length=");
+      builder.append(length);
+      builder.append(", path=");
+      builder.append(path);
+      builder.append(", replication=");
+      builder.append(replication);
+      builder.append(", mtime=");
+      builder.append(mtime);
+      builder.append(", atime=");
+      builder.append(atime);
+      builder.append(", blockSize=");
+      builder.append(blockSize);
+      builder.append(", blocks=");
+      builder.append(Arrays.toString(blocks));
+      builder.append(", permissions=");
+      builder.append(permissions);
+      builder.append(", clientName=");
+      builder.append(clientName);
+      builder.append(", clientMachine=");
+      builder.append(clientMachine);
+      builder.append(", opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   static class AddOp extends AddCloseOp {
@@ -315,6 +346,14 @@ private AddOp() {
     static AddOp getInstance() {
       return (AddOp)opInstances.get().get(OP_ADD);
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("AddOp ");
+      builder.append(stringifyMembers());
+      return builder.toString();
+    }
   }
 
   static class CloseOp extends AddCloseOp {
@@ -325,6 +364,14 @@ private CloseOp() {
     static CloseOp getInstance() {
       return (CloseOp)opInstances.get().get(OP_CLOSE);
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("CloseOp ");
+      builder.append(stringifyMembers());
+      return builder.toString();
+    }
   }
 
   static class SetReplicationOp extends FSEditLogOp {
@@ -366,6 +413,21 @@ void readFields(DataInputStream in, int logVersion)
         this.replication = readShort(in);
       }
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("SetReplicationOp [path=");
+      builder.append(path);
+      builder.append(", replication=");
+      builder.append(replication);
+      builder.append(", opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   static class ConcatDeleteOp extends FSEditLogOp {
@@ -440,6 +502,25 @@ void readFields(DataInputStream in, int logVersion)
         this.timestamp = readLong(in);
       }
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("ConcatDeleteOp [length=");
+      builder.append(length);
+      builder.append(", trg=");
+      builder.append(trg);
+      builder.append(", srcs=");
+      builder.append(Arrays.toString(srcs));
+      builder.append(", timestamp=");
+      builder.append(timestamp);
+      builder.append(", opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   static class RenameOldOp extends FSEditLogOp {
@@ -497,6 +578,25 @@ void readFields(DataInputStream in, int logVersion)
         this.timestamp = readLong(in);
       }
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("RenameOldOp [length=");
+      builder.append(length);
+      builder.append(", src=");
+      builder.append(src);
+      builder.append(", dst=");
+      builder.append(dst);
+      builder.append(", timestamp=");
+      builder.append(timestamp);
+      builder.append(", opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   static class DeleteOp extends FSEditLogOp {
@@ -545,6 +645,23 @@ void readFields(DataInputStream in, int logVersion)
         this.timestamp = readLong(in);
       }
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("DeleteOp [length=");
+      builder.append(length);
+      builder.append(", path=");
+      builder.append(path);
+      builder.append(", timestamp=");
+      builder.append(timestamp);
+      builder.append(", opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   static class MkdirOp extends FSEditLogOp {
@@ -623,6 +740,25 @@ void readFields(DataInputStream in, int logVersion)
         this.permissions = null;
       }
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("MkdirOp [length=");
+      builder.append(length);
+      builder.append(", path=");
+      builder.append(path);
+      builder.append(", timestamp=");
+      builder.append(timestamp);
+      builder.append(", permissions=");
+      builder.append(permissions);
+      builder.append(", opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   static class SetGenstampOp extends FSEditLogOp {
@@ -652,6 +788,19 @@ void readFields(DataInputStream in, int logVersion)
         throws IOException {
       this.genStamp = FSImageSerialization.readLong(in);
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("SetGenstampOp [genStamp=");
+      builder.append(genStamp);
+      builder.append(", opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   @SuppressWarnings("deprecation")
@@ -676,6 +825,17 @@ void readFields(DataInputStream in, int logVersion)
       //Datanodes are not persistent any more.
       FSImageSerialization.DatanodeImage.skipOne(in);
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("DatanodeAddOp [opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   @SuppressWarnings("deprecation")
@@ -701,6 +861,17 @@ void readFields(DataInputStream in, int logVersion)
       nodeID.readFields(in);
       //Datanodes are not persistent any more.
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("DatanodeRemoveOp [opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   static class SetPermissionsOp extends FSEditLogOp {
@@ -738,6 +909,21 @@ void readFields(DataInputStream in, int logVersion)
       this.src = FSImageSerialization.readString(in);
       this.permissions = FsPermission.read(in);
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("SetPermissionsOp [src=");
+      builder.append(src);
+      builder.append(", permissions=");
+      builder.append(permissions);
+      builder.append(", opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   static class SetOwnerOp extends FSEditLogOp {
@@ -783,6 +969,23 @@ void readFields(DataInputStream in, int logVersion)
       this.username = FSImageSerialization.readString_EmptyAsNull(in);
       this.groupname = FSImageSerialization.readString_EmptyAsNull(in);
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("SetOwnerOp [src=");
+      builder.append(src);
+      builder.append(", username=");
+      builder.append(username);
+      builder.append(", groupname=");
+      builder.append(groupname);
+      builder.append(", opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   static class SetNSQuotaOp extends FSEditLogOp {
@@ -809,6 +1012,21 @@ void readFields(DataInputStream in, int logVersion)
       this.src = FSImageSerialization.readString(in);
       this.nsQuota = FSImageSerialization.readLong(in);
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("SetNSQuotaOp [src=");
+      builder.append(src);
+      builder.append(", nsQuota=");
+      builder.append(nsQuota);
+      builder.append(", opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   static class ClearNSQuotaOp extends FSEditLogOp {
@@ -833,6 +1051,19 @@ void readFields(DataInputStream in, int logVersion)
         throws IOException {
       this.src = FSImageSerialization.readString(in);
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("ClearNSQuotaOp [src=");
+      builder.append(src);
+      builder.append(", opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   static class SetQuotaOp extends FSEditLogOp {
@@ -878,6 +1109,23 @@ void readFields(DataInputStream in, int logVersion)
       this.nsQuota = FSImageSerialization.readLong(in);
       this.dsQuota = FSImageSerialization.readLong(in);
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("SetQuotaOp [src=");
+      builder.append(src);
+      builder.append(", nsQuota=");
+      builder.append(nsQuota);
+      builder.append(", dsQuota=");
+      builder.append(dsQuota);
+      builder.append(", opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   static class TimesOp extends FSEditLogOp {
@@ -936,6 +1184,25 @@ void readFields(DataInputStream in, int logVersion)
         this.atime = readLong(in);
       }
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("TimesOp [length=");
+      builder.append(length);
+      builder.append(", path=");
+      builder.append(path);
+      builder.append(", mtime=");
+      builder.append(mtime);
+      builder.append(", atime=");
+      builder.append(atime);
+      builder.append(", opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   static class SymlinkOp extends FSEditLogOp {
@@ -1011,6 +1278,29 @@ void readFields(DataInputStream in, int logVersion)
       }
       this.permissionStatus = PermissionStatus.read(in);
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("SymlinkOp [length=");
+      builder.append(length);
+      builder.append(", path=");
+      builder.append(path);
+      builder.append(", value=");
+      builder.append(value);
+      builder.append(", mtime=");
+      builder.append(mtime);
+      builder.append(", atime=");
+      builder.append(atime);
+      builder.append(", permissionStatus=");
+      builder.append(permissionStatus);
+      builder.append(", opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   static class RenameOp extends FSEditLogOp {
@@ -1097,6 +1387,27 @@ static BytesWritable toBytesWritable(Rename... options) {
       }
       return new BytesWritable(bytes);
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("RenameOp [length=");
+      builder.append(length);
+      builder.append(", src=");
+      builder.append(src);
+      builder.append(", dst=");
+      builder.append(dst);
+      builder.append(", timestamp=");
+      builder.append(timestamp);
+      builder.append(", options=");
+      builder.append(Arrays.toString(options));
+      builder.append(", opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   static class ReassignLeaseOp extends FSEditLogOp {
@@ -1142,6 +1453,23 @@ void readFields(DataInputStream in, int logVersion)
       this.path = FSImageSerialization.readString(in);
       this.newHolder = FSImageSerialization.readString(in);
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("ReassignLeaseOp [leaseHolder=");
+      builder.append(leaseHolder);
+      builder.append(", path=");
+      builder.append(path);
+      builder.append(", newHolder=");
+      builder.append(newHolder);
+      builder.append(", opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   static class GetDelegationTokenOp extends FSEditLogOp {
@@ -1185,6 +1513,21 @@ void readFields(DataInputStream in, int logVersion)
         this.expiryTime = readLong(in);
       }
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("GetDelegationTokenOp [token=");
+      builder.append(token);
+      builder.append(", expiryTime=");
+      builder.append(expiryTime);
+      builder.append(", opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   static class RenewDelegationTokenOp extends FSEditLogOp {
@@ -1228,6 +1571,21 @@ void readFields(DataInputStream in, int logVersion)
         this.expiryTime = readLong(in);
       }
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("RenewDelegationTokenOp [token=");
+      builder.append(token);
+      builder.append(", expiryTime=");
+      builder.append(expiryTime);
+      builder.append(", opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   static class CancelDelegationTokenOp extends FSEditLogOp {
@@ -1259,6 +1617,19 @@ void readFields(DataInputStream in, int logVersion)
       this.token = new DelegationTokenIdentifier();
       this.token.readFields(in);
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("CancelDelegationTokenOp [token=");
+      builder.append(token);
+      builder.append(", opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   static class UpdateMasterKeyOp extends FSEditLogOp {
@@ -1289,6 +1660,19 @@ void readFields(DataInputStream in, int logVersion)
       this.key = new DelegationKey();
       this.key.readFields(in);
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("UpdateMasterKeyOp [key=");
+      builder.append(key);
+      builder.append(", opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
   
   static class LogSegmentOp extends FSEditLogOp {
@@ -1311,6 +1695,17 @@ public void readFields(DataInputStream in, int logVersion)
     void writeFields(DataOutputStream out) throws IOException {
       // no data stored
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("LogSegmentOp [opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   static class InvalidOp extends FSEditLogOp {
@@ -1331,6 +1726,17 @@ void readFields(DataInputStream in, int logVersion)
         throws IOException {
       // nothing to read
     }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("InvalidOp [opCode=");
+      builder.append(opCode);
+      builder.append(", txid=");
+      builder.append(txid);
+      builder.append("]");
+      return builder.toString();
+    }
   }
 
   static private short readShort(DataInputStream in) throws IOException {