HDFS-4082. Add editlog opcodes for snapshot create and delete operations. Contributed by suresh

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-2802@1400247 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -6,6 +6,9 @@ Branch-2802 Snapshot (Unreleased)
 
     HDFS-4076. Support snapshot of single files.  (szetszwo)
 
+    HDFS-4082. Add editlog opcodes for snapshot create and delete operations.
+    (suresh via szetszwo)
+
 Trunk (Unreleased)
 
   INCOMPATIBLE CHANGES

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

@@ -94,7 +94,8 @@ public class LayoutVersion {
         "Use LongWritable and ShortWritable directly instead of ArrayWritable of UTF8"),
     OPTIMIZE_PERSIST_BLOCKS(-40,
         "Serialize block lists with delta-encoded variable length ints, " +
-        "add OP_UPDATE_BLOCKS");
+        "add OP_UPDATE_BLOCKS"),
+    SNAPSHOT(-41, "Support for snapshot feature");
     
     final int lv;
     final int ancestorLV;

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

@@ -47,7 +47,9 @@ import org.apache.hadoop.hdfs.server.namenode.FSEditLogOp.AddOp;
 import org.apache.hadoop.hdfs.server.namenode.FSEditLogOp.CancelDelegationTokenOp;
 import org.apache.hadoop.hdfs.server.namenode.FSEditLogOp.CloseOp;
 import org.apache.hadoop.hdfs.server.namenode.FSEditLogOp.ConcatDeleteOp;
+import org.apache.hadoop.hdfs.server.namenode.FSEditLogOp.CreateSnapshotOp;
 import org.apache.hadoop.hdfs.server.namenode.FSEditLogOp.DeleteOp;
+import org.apache.hadoop.hdfs.server.namenode.FSEditLogOp.DeleteSnapshotOp;
 import org.apache.hadoop.hdfs.server.namenode.FSEditLogOp.GetDelegationTokenOp;
 import org.apache.hadoop.hdfs.server.namenode.FSEditLogOp.LogSegmentOp;
 import org.apache.hadoop.hdfs.server.namenode.FSEditLogOp.MkdirOp;
@@ -863,6 +865,18 @@ public class FSEditLog implements LogsPurgeable {
     logEdit(op);
   }
   
+  void logCreateSnapshot(String snapName, String snapRoot) {
+    CreateSnapshotOp op = CreateSnapshotOp.getInstance(cache.get())
+        .setSnapshotName(snapName).setSnapshotRoot(snapRoot);
+    logEdit(op);
+  }
+  
+  void logDeleteSnapshot(String snapName, String snapRoot) {
+    DeleteSnapshotOp op = DeleteSnapshotOp.getInstance(cache.get())
+        .setSnapshotName(snapName).setSnapshotRoot(snapRoot);
+    logEdit(op);
+  }
+  
   /**
    * Get all the journals this edit log is currently operating on.
    */

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

@@ -2160,6 +2160,128 @@ public abstract class FSEditLogOp {
     }
   }
 
+  /**
+   * Operation corresponding to creating a snapshot
+   */
+  static class CreateSnapshotOp extends FSEditLogOp {
+    String snapshotName;
+    String snapshotRoot;
+    
+    public CreateSnapshotOp() {
+      super(OP_CREATE_SNAPSHOT);
+    }
+    
+    static CreateSnapshotOp getInstance(OpInstanceCache cache) {
+      return (CreateSnapshotOp)cache.get(OP_CREATE_SNAPSHOT);
+    }
+    
+    CreateSnapshotOp setSnapshotName(String snapName) {
+      this.snapshotName = snapName;
+      return this;
+    }
+
+    public CreateSnapshotOp setSnapshotRoot(String snapRoot) {
+      snapshotRoot = snapRoot;
+      return this;
+    }
+    
+    @Override
+    void readFields(DataInputStream in, int logVersion) throws IOException {
+      snapshotName = FSImageSerialization.readString(in);
+      snapshotRoot = FSImageSerialization.readString(in);
+    }
+
+    @Override
+    public void writeFields(DataOutputStream out) throws IOException {
+      FSImageSerialization.writeString(snapshotName, out);
+      FSImageSerialization.writeString(snapshotRoot, out);
+    }
+
+    @Override
+    protected void toXml(ContentHandler contentHandler) throws SAXException {
+      XMLUtils.addSaxString(contentHandler, "SNAPSHOTNAME", snapshotName);
+      XMLUtils.addSaxString(contentHandler, "SNAPSHOTROOT", snapshotRoot);
+    }
+
+    @Override
+    void fromXml(Stanza st) throws InvalidXmlException {
+      snapshotName = st.getValue("SNAPSHOTNAME");
+      snapshotRoot = st.getValue("SNAPSHOTROOT");
+    }
+    
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("CreateSnapshotOp [snapshotName=");
+      builder.append(snapshotName);
+      builder.append(", snapshotRoot=");
+      builder.append(snapshotRoot);
+      builder.append("]");
+      return builder.toString();
+    }
+  }
+  
+  /**
+   * Operation corresponding to delete a snapshot
+   */
+  static class DeleteSnapshotOp extends FSEditLogOp {
+    String snapshotName;
+    String snapshotRoot;
+    
+    DeleteSnapshotOp() {
+      super(OP_DELETE_SNAPSHOT);
+    }
+    
+    static DeleteSnapshotOp getInstance(OpInstanceCache cache) {
+      return (DeleteSnapshotOp)cache.get(OP_DELETE_SNAPSHOT);
+    }
+    
+    DeleteSnapshotOp setSnapshotName(String snapName) {
+      this.snapshotName = snapName;
+      return this;
+    }
+
+    DeleteSnapshotOp setSnapshotRoot(String snapRoot) {
+      snapshotRoot = snapRoot;
+      return this;
+    }
+    
+    @Override
+    void readFields(DataInputStream in, int logVersion) throws IOException {
+      snapshotName = FSImageSerialization.readString(in);
+      snapshotRoot = FSImageSerialization.readString(in);
+    }
+
+    @Override
+    public void writeFields(DataOutputStream out) throws IOException {
+      FSImageSerialization.writeString(snapshotName, out);
+      FSImageSerialization.writeString(snapshotRoot, out);
+    }
+
+    @Override
+    protected void toXml(ContentHandler contentHandler) throws SAXException {
+      XMLUtils.addSaxString(contentHandler, "SNAPSHOTNAME", snapshotName);
+      XMLUtils.addSaxString(contentHandler, "SNAPSHOTROOT", snapshotRoot);
+    }
+
+    @Override
+    void fromXml(Stanza st) throws InvalidXmlException {
+      snapshotName = st.getValue("SNAPSHOTNAME");
+      snapshotRoot = st.getValue("SNAPSHOTROOT");
+    }
+    
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("DeleteSnapshotOp [snapshotName=");
+      builder.append(snapshotName);
+      builder.append(", snapshotRoot=");
+      builder.append(snapshotRoot);
+      builder.append("]");
+      return builder.toString();
+    }
+  }
+  
   static private short readShort(DataInputStream in) throws IOException {
     return Short.parseShort(FSImageSerialization.readString(in));
   }

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

@@ -56,7 +56,9 @@ public enum FSEditLogOpCodes {
   OP_REASSIGN_LEASE             ((byte) 22),
   OP_END_LOG_SEGMENT            ((byte) 23),
   OP_START_LOG_SEGMENT          ((byte) 24),
-  OP_UPDATE_BLOCKS              ((byte) 25);
+  OP_UPDATE_BLOCKS              ((byte) 25),
+  OP_CREATE_SNAPSHOT            ((byte) 26),
+  OP_DELETE_SNAPSHOT            ((byte) 27);
 
   private byte opCode;