core: PseudoFS: Properly resolve the inner root inode

When we try to resolve the inner FS's root inode given a pseudo inode in
PseudoFS, we can directly return the inner FS's root inode as returned
by VirtualFileSystem#getRootInode(), which is most likely cached,
instead of creating new Inode instances all over again.

This further reduces the number of Inode allocations.

Also fail with BadHandleException for any other pseudo inode because
they will by definition be invalid in the underlying file system.

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

Author: kohlschuetter

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

@@ -746,8 +746,17 @@ private boolean inheritUidGid(Inode inode) {
      *
      * @param inode The {@link Inode} as passed from and to the NFS client.
      * @return The {@link Inode} as passed from {@link PseudoFs} to the underlying {@link VirtualFileSystem}.
+     * @throws IOException on error.
      */
-    private Inode innerInode(Inode inode) {
+    private Inode innerInode(Inode inode) throws IOException {
+        if (inode.isPseudoInode()) {
+            Inode innerRootInode = _inner.getRootInode();
+            if (innerRootInode.getFileIdKey().equals(inode.getFileIdKey())) {
+                return innerRootInode;
+            } else {
+                throw new BadHandleException();
+            }
+        }
         return Inode.innerInode(inode);
     }
 }