core: OperationLOCK: Limit scope of addDisposeListener lambda

When specifying lambdas for cleanup operations, it is good practice to
reduce the scope of instances referenced ("pinned") in the lambda scope.

Right now, we reference unnecessary objects, adding to heap
fragmentation.

Reduce the scope of referenced objects by accessing the required
references before entering the dispose listener lambda.

Signed-off-by: Christian Kohlschütter <[email protected]>

Author: kohlschuetter

core/src/main/java/org/dcache/nfs/v4/OperationLOCK.java

@@ -24,8 +24,10 @@
 import org.dcache.nfs.status.InvalException;
 import org.dcache.nfs.status.OpenModeException;
 import org.dcache.nfs.status.ServerFaultException;
+import org.dcache.nfs.util.Opaque;
 import org.dcache.nfs.v4.nlm.LockDeniedException;
 import org.dcache.nfs.v4.nlm.LockException;
+import org.dcache.nfs.v4.nlm.LockManager;
 import org.dcache.nfs.v4.nlm.NlmLock;
 import org.dcache.nfs.v4.xdr.LOCK4denied;
 import org.dcache.nfs.v4.xdr.LOCK4resok;
@@ -118,12 +120,12 @@ public void process(CompoundContext context, nfs_resop4 result) throws ChimeraNF
 
             NlmLock lock = new NlmLock(lockOwner, _args.oplock.locktype, _args.oplock.offset.value,
                     _args.oplock.length.value);
-            context.getLm().lock(inode.getLockKey(), lock);
+            Opaque lockKey = inode.getLockKey();
+            LockManager lm = context.getLm();
+            lm.lock(lockKey, lock);
 
             // ensure, that on close locks will be released
-            lock_state.addDisposeListener(s -> {
-                context.getLm().unlockIfExists(inode.getLockKey(), lock);
-            });
+            lock_state.addDisposeListener(s -> lm.unlockIfExists(lockKey, lock));
 
             // FIXME: we might run into race condition, thus updating sedid must be fenced!
             lock_state.bumpSeqid();