HBASE-529 RegionServer needs to recover if datanode goes down

-HLog will now try to reopen the log twice on append failure before taking the region server down

git-svn-id: https://svn.apache.org/repos/asf/hadoop/hbase/trunk@638597 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -93,6 +93,7 @@ Hbase Change Log
    HBASE-477   Add support for an HBASE_CLASSPATH
    HBASE-443   Move internal classes out of HStore
    HBASE-515   At least double default timeouts between regionserver and master
+   HBASE-529   RegionServer needs to recover if datanode goes down
    
 Branch 0.1
 

src/java/org/apache/hadoop/hbase/regionserver/HLog.java

@@ -383,7 +383,19 @@ public class HLog implements HConstants {
           new HLogKey(regionName, tableName, key.getRow(), seqNum[counter++]);
         HLogEdit logEdit =
           new HLogEdit(key.getColumn(), es.getValue(), key.getTimestamp());
-      	this.writer.append(logKey, logEdit);
+        try {
+      	  this.writer.append(logKey, logEdit);
+      	} catch (IOException e) {
+      	  LOG.error("Could not append to log. Opening new log. Exception: ", e);
+          rollWriter();
+          try {
+            this.writer.append(logKey, logEdit);
+          } catch (IOException e2) { 
+            LOG.fatal("Could not append to log the second time because " + 
+              e2.toString() + ", aborting.");
+            throw e2;
+          }
+      	}
         this.numEntries++;
       }
     }