HDFS-4086. Add editlog opcodes to allow and disallow snapshots on a directory. Contributed by Brandon Li.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-2802@1400298 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-2802.txt

@@ -5,4 +5,7 @@ Branch-2802 Snapshot (Unreleased)
   HDFS-4082. Add editlog opcodes for snapshot create and delete operations.
   (suresh via szetszwo)
 
+  HDFS-4086. Add editlog opcodes to allow and disallow snapshots on a 
+  directory. (Brandon Li via suresh)
+
 

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

@@ -44,12 +44,14 @@
 import org.apache.hadoop.hdfs.server.common.Storage.FormatConfirmable;
 import org.apache.hadoop.hdfs.server.common.Storage.StorageDirectory;
 import org.apache.hadoop.hdfs.server.namenode.FSEditLogOp.AddOp;
+import org.apache.hadoop.hdfs.server.namenode.FSEditLogOp.AllowSnapshotOp;
 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.DisallowSnapshotOp;
 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;
@@ -877,6 +879,18 @@ void logDeleteSnapshot(String snapName, String snapRoot) {
     logEdit(op);
   }
   
+  void logAllowSnapshot(String snapName, String snapRoot) {
+    AllowSnapshotOp op = AllowSnapshotOp.getInstance(cache.get())
+        .setSnapshotRoot(snapRoot);
+    logEdit(op);
+  }
+
+  void logDisallowSnapshot(String snapName, String snapRoot) {
+    DisallowSnapshotOp op = DisallowSnapshotOp.getInstance(cache.get())
+        .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

@@ -2281,7 +2281,115 @@ public String toString() {
       return builder.toString();
     }
   }
-  
+
+  /**
+   * Operation corresponding to allow creating snapshot on a directory
+   */
+  static class AllowSnapshotOp extends FSEditLogOp {
+    String snapshotRoot;
+
+    public AllowSnapshotOp() {
+      super(OP_ALLOW_SNAPSHOT);
+    }
+
+    public AllowSnapshotOp(String snapRoot) {
+      super(OP_ALLOW_SNAPSHOT);
+      snapshotRoot = snapRoot;
+    }
+
+    static AllowSnapshotOp getInstance(OpInstanceCache cache) {
+      return (AllowSnapshotOp) cache.get(OP_ALLOW_SNAPSHOT);
+    }
+
+    public AllowSnapshotOp setSnapshotRoot(String snapRoot) {
+      snapshotRoot = snapRoot;
+      return this;
+    }
+
+    @Override
+    void readFields(DataInputStream in, int logVersion) throws IOException {
+      snapshotRoot = FSImageSerialization.readString(in);
+    }
+
+    @Override
+    public void writeFields(DataOutputStream out) throws IOException {
+      FSImageSerialization.writeString(snapshotRoot, out);
+    }
+
+    @Override
+    protected void toXml(ContentHandler contentHandler) throws SAXException {
+      XMLUtils.addSaxString(contentHandler, "SNAPSHOTROOT", snapshotRoot);
+    }
+
+    @Override
+    void fromXml(Stanza st) throws InvalidXmlException {
+      snapshotRoot = st.getValue("SNAPSHOTROOT");
+    }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("AllowSnapshotOp [snapshotRoot=");
+      builder.append(snapshotRoot);
+      builder.append("]");
+      return builder.toString();
+    }
+  }
+
+  /**
+   * Operation corresponding to disallow creating snapshot on a directory
+   */
+  static class DisallowSnapshotOp extends FSEditLogOp {
+    String snapshotRoot;
+
+    public DisallowSnapshotOp() {
+      super(OP_DISALLOW_SNAPSHOT);
+    }
+
+    public DisallowSnapshotOp(String snapRoot) {
+      super(OP_DISALLOW_SNAPSHOT);
+      snapshotRoot = snapRoot;
+    }
+
+    static DisallowSnapshotOp getInstance(OpInstanceCache cache) {
+      return (DisallowSnapshotOp) cache.get(OP_DISALLOW_SNAPSHOT);
+    }
+
+    public DisallowSnapshotOp setSnapshotRoot(String snapRoot) {
+      snapshotRoot = snapRoot;
+      return this;
+    }
+
+    @Override
+    void readFields(DataInputStream in, int logVersion) throws IOException {
+      snapshotRoot = FSImageSerialization.readString(in);
+    }
+
+    @Override
+    public void writeFields(DataOutputStream out) throws IOException {
+      FSImageSerialization.writeString(snapshotRoot, out);
+    }
+
+    @Override
+    protected void toXml(ContentHandler contentHandler) throws SAXException {
+      XMLUtils.addSaxString(contentHandler, "SNAPSHOTROOT", snapshotRoot);
+    }
+
+    @Override
+    void fromXml(Stanza st) throws InvalidXmlException {
+      snapshotRoot = st.getValue("SNAPSHOTROOT");
+    }
+
+    @Override
+    public String toString() {
+      StringBuilder builder = new StringBuilder();
+      builder.append("DisallowSnapshotOp [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

@@ -58,7 +58,9 @@ public enum FSEditLogOpCodes {
   OP_START_LOG_SEGMENT          ((byte) 24),
   OP_UPDATE_BLOCKS              ((byte) 25),
   OP_CREATE_SNAPSHOT            ((byte) 26),
-  OP_DELETE_SNAPSHOT            ((byte) 27);
+  OP_DELETE_SNAPSHOT            ((byte) 27),
+  OP_ALLOW_SNAPSHOT             ((byte) 28),
+  OP_DISALLOW_SNAPSHOT          ((byte) 29);
 
   private byte opCode;