core: Allow reuse of "Opaque" file id key

Previously, we were creating Opaque objects multiple times for the same
file ID of an Inode.

Let Inode return the "opaque" key: introduce a "getFileIdKey" method
that always returns the same instance.

Related: #149
Signed-off-by: Christian Kohlschütter <[email protected]>

Author: kohlschuetter

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

@@ -242,7 +242,7 @@ public OpenRecord addOpen(NFS4Client client, StateOwner owner, Inode inode, int
         // client explicitly requested write delegation
         boolean wantWriteDelegation = (shareAccess & nfs4_prot.OPEN4_SHARE_ACCESS_WANT_WRITE_DELEG) != 0;
 
-        Opaque fileId = new Opaque(inode.getFileId());
+        Opaque fileId = inode.getFileIdKey();
         Lock lock = filesLock.get(fileId);
         lock.lock();
         try {
@@ -376,7 +376,7 @@ public OpenRecord addOpen(NFS4Client client, StateOwner owner, Inode inode, int
     public stateid4 downgradeOpen(NFS4Client client, stateid4 stateid, Inode inode, int shareAccess, int shareDeny)
             throws ChimeraNFSException {
 
-        Opaque fileId = new Opaque(inode.getFileId());
+        Opaque fileId = inode.getFileIdKey();
         Lock lock = filesLock.get(fileId);
         lock.lock();
         try {
@@ -426,7 +426,7 @@ public stateid4 downgradeOpen(NFS4Client client, stateid4 stateid, Inode inode,
     public void delegationReturn(NFS4Client client, stateid4 stateid, Inode inode)
             throws ChimeraNFSException {
 
-        Opaque fileId = new Opaque(inode.getFileId());
+        Opaque fileId = inode.getFileIdKey();
         Lock lock = filesLock.get(fileId);
         lock.lock();
         try {
@@ -464,7 +464,7 @@ public void delegationReturn(NFS4Client client, stateid4 stateid, Inode inode)
     public int getShareAccess(NFS4Client client, Inode inode, stateid4 stateid)
             throws ChimeraNFSException {
 
-        Opaque fileId = new Opaque(inode.getFileId());
+        Opaque fileId = inode.getFileIdKey();
         Lock lock = filesLock.get(fileId);
         lock.lock();
         try {
@@ -527,7 +527,7 @@ public int getShareAccess(NFS4Client client, Inode inode, stateid4 stateid)
      */
     void removeOpen(Inode inode, stateid4 stateid) {
 
-        Opaque fileId = new Opaque(inode.getFileId());
+        Opaque fileId = inode.getFileIdKey();
         Lock lock = filesLock.get(fileId);
         lock.lock();
         try {

core/src/main/java/org/dcache/nfs/vfs/Inode.java

@@ -23,6 +23,8 @@
 import java.nio.ByteOrder;
 import java.util.Arrays;
 
+import org.dcache.nfs.util.Opaque;
+
 import com.google.common.io.BaseEncoding;
 
 /**
@@ -48,9 +50,10 @@ public class Inode {
     private final int generation;
     private final int exportIdx;
     private final int type;
-    private final byte[] fs_opaque;
     private final byte[] nfsHandle;
 
+    private final Opaque opaqueKey;
+
     @Deprecated(forRemoval = true)
     public Inode(FileHandle fh) {
         this(fh.bytes());
@@ -71,9 +74,9 @@ public Inode(int generation, int exportIdx, int type, byte[] fs_opaque) {
         this.generation = generation;
         this.exportIdx = exportIdx;
         this.type = type;
-        this.fs_opaque = fs_opaque;
+        this.opaqueKey = new Opaque(fs_opaque.clone());
 
-        this.nfsHandle = buildNfsHandle();
+        this.nfsHandle = buildNfsHandle(fs_opaque);
     }
 
     /**
@@ -106,8 +109,9 @@ public Inode(byte[] bytes) {
         exportIdx = b.getInt();
         type = (int) b.get();
         int olen = (int) b.get();
-        fs_opaque = new byte[olen];
+        byte[] fs_opaque = new byte[olen];
         b.get(fs_opaque);
+        this.opaqueKey = new Opaque(fs_opaque);
 
         this.nfsHandle = bytes.clone();
     }
@@ -141,14 +145,25 @@ public static Inode forFile(byte[] bytes) {
     }
 
     public byte[] getFileId() {
-        return fs_opaque;
+        return opaqueKey.getOpaque().clone();
+    }
+
+    /**
+     * Returns a key suitable for identifying the underlying inode/file referred to by this instance, providing a
+     * {@link Object#equals(Object)} and {@link Object#hashCode()} implementation that may or may not be different from
+     * {@link Inode#equals(Object)} and {@link Inode#hashCode()}.
+     * 
+     * @return The fileId key.
+     */
+    public Opaque getFileIdKey() {
+        return opaqueKey;
     }
 
     public byte[] toNfsHandle() {
         return nfsHandle.clone();
     }
 
-    private byte[] buildNfsHandle() {
+    private byte[] buildNfsHandle(byte[] fs_opaque) {
         int len = fs_opaque.length + MIN_LEN;
         byte[] bytes = new byte[len];
         ByteBuffer b = ByteBuffer.wrap(bytes);

core/src/main/java/org/dcache/nfs/vfs/VfsCache.java

@@ -219,7 +219,7 @@ private void updateLookupCache(Inode parent, String path, Inode inode) {
      * @param inode The inode for which cached state value should be invalidated.
      */
     public void invalidateStatCache(final Inode inode) {
-        _statCache.invalidate(new Opaque(inode.getFileId()));
+        _statCache.invalidate(inode.getFileIdKey());
     }
 
     private void updateParentCache(Inode inode, Inode parent) {
@@ -246,7 +246,7 @@ private Inode lookupFromCacheOrLoad(final Inode parent, final String path) throw
 
     private Stat statFromCacheOrLoad(final Inode inode) throws IOException {
         try {
-            return _statCache.get(new Opaque(inode.getFileId()), () -> _inner.getattr(inode));
+            return _statCache.get(inode.getFileIdKey(), () -> _inner.getattr(inode));
         } catch (ExecutionException e) {
             Throwable t = e.getCause();
             Throwables.throwIfInstanceOf(t, IOException.class);