basic-server: LocalFileSystem: throw StaleException for missing Inode

When trying to resolve an Inode object that doesn't exist, we currently
throw NoEntException.

When restarting a server, NFS clients may still request old Inodes,
which (apart from the root inode) will not exist, since they're all UUID
generated.

This is a problem at for the macOS NFS client, which may fail and not
recover from this situation.

Throw StaleException instead, which will instruct the NFS client to
refresh its file handles/Inodes. A "cd $(pwd)" may still be required if
the user was in an NFS mount point filetree upon server restart, but at
least it's recovering now.

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

Author: kohlschuetter

basic-server/src/main/java/org/dcache/nfs4j/server/LocalFileSystem.java

@@ -34,6 +34,7 @@
 import javax.security.auth.Subject;
 
 import org.cliffc.high_scale_lib.NonBlockingHashMap;
+import org.dcache.nfs.ChimeraNFSException;
 import org.dcache.nfs.FsExport;
 import org.dcache.nfs.status.ExistException;
 import org.dcache.nfs.status.InvalException;
@@ -43,6 +44,7 @@
 import org.dcache.nfs.status.NotSuppException;
 import org.dcache.nfs.status.PermException;
 import org.dcache.nfs.status.ServerFaultException;
+import org.dcache.nfs.status.StaleException;
 import org.dcache.nfs.v4.NfsIdMapping;
 import org.dcache.nfs.v4.SimpleIdMap;
 import org.dcache.nfs.v4.xdr.nfsace4;
@@ -86,10 +88,10 @@ private static Inode toFh(UUID inodeNumber) {
         return Inode.forFile(toByteArray(inodeNumber));
     }
 
-    private Path resolveInode(Inode inodeNumber) throws NoEntException {
+    private Path resolveInode(Inode inodeNumber) throws ChimeraNFSException {
         Path path = inodeToPath.get(inodeNumber);
         if (path == null) {
-            throw new NoEntException("inode #" + inodeNumber);
+            throw new StaleException("inode #" + inodeNumber);
         }
         return path;
     }