HBASE-21384 Procedure with holdlock=false should not be restored lock when restarts

hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/LockAndQueue.java

@@ -73,7 +73,8 @@ public class LockAndQueue implements LockStatus {
 
   @Override
   public boolean hasParentLock(Procedure<?> proc) {
-    // TODO: need to check all the ancestors
+    // TODO: need to check all the ancestors. need to passed in the procedures
+    // to find the ancestors.
     return proc.hasParent() &&
       (isLockOwner(proc.getParentProcId()) || isLockOwner(proc.getRootProcId()));
   }

hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/Procedure.java

@@ -992,7 +992,13 @@ public abstract class Procedure<TEnvironment> implements Comparable<Procedure<TE
       LOG.debug("{} is already bypassed, skip acquiring lock.", this);
       return;
     }
-
+    // this can happen if the parent stores the sub procedures but before it can
+    // release its lock, the master restarts
+    if (getState() == ProcedureState.WAITING && !holdLock(env)) {
+      LOG.debug("{} is in WAITING STATE, and holdLock= false, skip acquiring lock.", this);
+      lockedWhenLoading = false;
+      return;
+    }
     LOG.debug("{} held the lock before restarting, call acquireLock to restore it.", this);
     LockState state = acquireLock(env);
     assert state == LockState.LOCK_ACQUIRED;

hbase-procedure/src/main/java/org/apache/hadoop/hbase/procedure2/ProcedureExecutor.java

@@ -653,7 +653,20 @@ public class ProcedureExecutor<TEnvironment> {
         sendProcedureLoadedNotification(p.getProcId());
       }
       // If the procedure holds the lock, put the procedure in front
-      if (p.isLockedWhenLoading()) {
+      // If its parent holds the lock, put the procedure in front
+      // TODO. Is that possible that its ancestor holds the lock?
+      // For now, the deepest procedure hierarchy is:
+      // ModifyTableProcedure -> ReopenTableProcedure ->
+      // MoveTableProcedure -> Unassign/AssignProcedure
+      // But ModifyTableProcedure and ReopenTableProcedure won't hold the lock
+      // So, check parent lock is enough(a tricky case is resovled by HBASE-21384).
+      // If some one change or add new procedures making 'grandpa' procedure
+      // holds the lock, but parent procedure don't hold the lock, there will
+      // be a problem here. We have to check one procedure's ancestors.
+      // And we need to change LockAndQueue.hasParentLock(Procedure<?> proc) method
+      // to check all ancestors too.
+      if (p.isLockedWhenLoading() || (p.hasParent() && procedures
+          .get(p.getParentProcId()).isLockedWhenLoading())) {
         scheduler.addFront(p, false);
       } else {
         // if it was not, it can wait.