HBASE-7523 Snapshot attempt with the name of a previously taken snapshot fails sometimes

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/hbase-7290@1445837 13f79535-47bb-0310-9956-ffa450edef68

hbase-server/src/main/java/org/apache/hadoop/hbase/master/snapshot/EnabledTableSnapshotHandler.java

@@ -74,7 +74,7 @@ public class EnabledTableSnapshotHandler extends TakeSnapshotHandler {
     Procedure proc = coordinator.startProcedure(this.monitor, this.snapshot.getName(),
       this.snapshot.toByteArray(), Lists.newArrayList(regionServers));
     if (proc == null) {
-      String msg = "Failed to submit distribute procedure for snapshot '"
+      String msg = "Failed to submit distributed procedure for snapshot '"
           + snapshot.getName() + "'";
       LOG.error(msg);
       throw new HBaseSnapshotException(msg);

hbase-server/src/main/java/org/apache/hadoop/hbase/procedure/Procedure.java

@@ -310,7 +310,8 @@ public class Procedure implements Callable<Void>, ForeignExceptionListener {
     }
     if (removed) {
       LOG.debug("Member: '" + member + "' released barrier for procedure'" + procName
-          + "', counting down latch");
+          + "', counting down latch.  Waiting for " + releasedBarrierLatch.getCount()
+          + " more");
     } else {
       LOG.warn("Member: '" + member + "' released barrier for procedure'" + procName
           + "', but we weren't waiting on it to release!");

hbase-server/src/main/java/org/apache/hadoop/hbase/procedure/ProcedureCoordinator.java

@@ -113,9 +113,16 @@ public class ProcedureCoordinator {
 
     // make sure we aren't already running an procedure of that name
     synchronized (procedures) {
-      if (procedures.get(procName) != null) {
+      Procedure oldProc = procedures.get(procName);
+      if (oldProc != null) {
+        // procedures are always eventually completed on both successful and failed execution
+        if (oldProc.completedLatch.getCount() != 0) {
+          LOG.warn("Procedure " + procName + " currently running.  Rejecting new request");
           return false;
         }
+        LOG.debug("Procedure " + procName + " was in running list but was completed.  Accepting new attempt.");
+        procedures.remove(procName);
+      }
     }
 
     // kick off the procedure's execution in a separate thread
@@ -128,6 +135,8 @@ public class ProcedureCoordinator {
       }
       return true;
     } catch (RejectedExecutionException e) {
+      LOG.warn("Procedure " + procName + " rejected by execution pool.  Propagating error and " +
+          "cancelling operation.", e);
       // the thread pool is full and we can't run the procedure
       proc.receive(new ForeignException(procName, e));
 

hbase-server/src/main/java/org/apache/hadoop/hbase/procedure/Subprocedure.java

@@ -185,7 +185,6 @@ abstract public class Subprocedure implements Callable<Void> {
 
       // make sure we didn't get an external exception
       rethrowException();
-      LOG.debug("Subprocedure '" + barrierName + "' locally completed");
     } catch (Exception e) {
       String msg = null;
       if (e instanceof InterruptedException) {

hbase-server/src/main/java/org/apache/hadoop/hbase/procedure/ZKProcedureMemberRpcs.java

@@ -87,7 +87,7 @@ public class ZKProcedureMemberRpcs implements ProcedureMemberRpcs {
           String parent = ZKUtil.getParent(path);
           // if its the end barrier, the procedure can be completed
           if (parent.equals(this.reachedZnode)) {
-            recievedReachedGlobalBarrier(path);
+            receivedReachedGlobalBarrier(path);
             return;
           } else if (parent.equals(this.abortZnode)) {
             abort(path);
@@ -104,10 +104,10 @@ public class ZKProcedureMemberRpcs implements ProcedureMemberRpcs {
       public void nodeChildrenChanged(String path) {
         LOG.info("Received children changed event:" + path);
         if (path.equals(this.acquiredZnode)) {
-          LOG.info("Recieved start event.");
+          LOG.info("Received start event.");
           waitForNewProcedures();
         } else if (path.equals(this.abortZnode)) {
-          LOG.info("Recieved abort event.");
+          LOG.info("Received abort event.");
           watchForAbortedProcedures();
         }
       }
@@ -134,7 +134,7 @@ public class ZKProcedureMemberRpcs implements ProcedureMemberRpcs {
    * Pass along the procedure global barrier notification to any listeners
    * @param path full znode path that cause the notification
    */
-  private void recievedReachedGlobalBarrier(String path) {
+  private void receivedReachedGlobalBarrier(String path) {
     LOG.debug("Recieved reached global barrier:" + path);
     String procName = ZKUtil.getNodeName(path);
     this.member.receivedReachedGlobalBarrier(procName);
@@ -244,7 +244,7 @@ public class ZKProcedureMemberRpcs implements ProcedureMemberRpcs {
       String reachedBarrier = zkController.getReachedBarrierNode(procName);
       LOG.debug("Watch for global barrier reached:" + reachedBarrier);
       if (ZKUtil.watchAndCheckExists(zkController.getWatcher(), reachedBarrier)) {
-        recievedReachedGlobalBarrier(reachedBarrier);
+        receivedReachedGlobalBarrier(reachedBarrier);
       }
     } catch (KeeperException e) {
       member.controllerConnectionFailure("Failed to acquire barrier for procedure: "