nfs41: change default behaviour if no layouts types specified in export

Motivation:
If no special export option is specified, the nfs server will publish
hard-coded default LAYOUT4_NFSV4_1_FILES as supported pNFS layout type.
Though this behavior is incorrect, the server might not support that
specific layout type, for example, it forced by (a) RHEL6 kernels have
picked only the first entry if multiple entries provided by server, and,
(b) RHEL6 have supported only LAYOUT4_NFSV4_1_FILES layout types. As
RHEL6 should not be in production anymore, the workaround should be
removed.

Modification:
Update GETATTR to publish all layout types that are supported by pNFS
server.

Result:
less weird workarounds.

Acked-by: Lea Morschel
Target: master

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

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009 - 2022 Deutsches Elektronen-Synchroton,
+ * Copyright (c) 2009 - 2023 Deutsches Elektronen-Synchroton,
  * Member of the Helmholtz Association, (DESY), HAMBURG, GERMANY
  *
  * This library is free software; you can redistribute it and/or modify
@@ -394,11 +394,11 @@ static Optional<? extends XdrAble> fattr2xdr(int fattr, VirtualFileSystem fs, In
                     .orElseThrow(AccessException::new) // should never happen as handled by PseudoFS first
                     .getLayoutTypes();
 
-		Set<layouttype4> supportedLayouts = pnfsDeviceManager.get().getLayoutTypes();
-
+                Set<layouttype4> supportedLayouts = pnfsDeviceManager.get().getLayoutTypes();
                 if (exportLayouts.isEmpty()) {
-                    // for backward compatibility, pick NFSv41_FILES layout if nothing is specified
-                    fs_layout_type.value = new int[] {layouttype4.LAYOUT4_NFSV4_1_FILES.getValue()};
+                    fs_layout_type.value = supportedLayouts.stream()
+                            .mapToInt(layouttype4::getValue)
+                            .toArray();
                 } else {
                     fs_layout_type.value = exportLayouts.stream()
                         .filter(e -> supportedLayouts.contains(e))

core/src/test/java/org/dcache/nfs/v4/OperationGETATTRTest.java

@@ -7,14 +7,15 @@
 import java.util.Optional;
 import org.dcache.nfs.ExportFile;
 import org.dcache.nfs.v4.xdr.fattr4_fs_layout_types;
-import org.dcache.nfs.v4.xdr.layouttype4;
 import org.dcache.nfs.v4.xdr.nfs4_prot;
 import org.dcache.oncrpc4j.rpc.RpcAuthTypeNone;
 import org.dcache.oncrpc4j.rpc.RpcCall;
 import org.dcache.oncrpc4j.rpc.RpcTransport;
 
 import org.junit.Test;
 
+import static org.dcache.nfs.v4.xdr.layouttype4.LAYOUT4_BLOCK_VOLUME;
+import static org.dcache.nfs.v4.xdr.layouttype4.LAYOUT4_OSD2_OBJECTS;
 import static org.junit.Assert.assertArrayEquals;
 import static org.mockito.Mockito.mock;
 
@@ -33,7 +34,7 @@ public void testDefaultLayoutType() throws IOException, URISyntaxException {
         RpcTransport transport = mock(RpcTransport.class);
         ExportFile exportFile = new ExportFile(ClassLoader.getSystemResource("org/dcache/nfs/exports").toURI());
 
-        given(dm.getLayoutTypes()).willReturn(EnumSet.allOf(layouttype4.class));
+        given(dm.getLayoutTypes()).willReturn(EnumSet.of(LAYOUT4_OSD2_OBJECTS, LAYOUT4_BLOCK_VOLUME));
         given(transport.getRemoteSocketAddress()).willReturn(new InetSocketAddress("172.16.4.1", 0));
 
         given(call.getCredential()).willReturn(new RpcAuthTypeNone());
@@ -47,8 +48,8 @@ public void testDefaultLayoutType() throws IOException, URISyntaxException {
 
         Optional<fattr4_fs_layout_types> res = (Optional<fattr4_fs_layout_types>) OperationGETATTR.fattr2xdr(nfs4_prot.FATTR4_FS_LAYOUT_TYPES, null, null, null, context);
 
-        assertArrayEquals("export without explicit layout type must return nfsv41_files layout",
-                new int[] {layouttype4.LAYOUT4_NFSV4_1_FILES.getValue()}, res.get().value);
+        assertArrayEquals("export without explicit layout type must return all configures layout types",
+                new int[] {LAYOUT4_OSD2_OBJECTS.getValue(), LAYOUT4_BLOCK_VOLUME.getValue()}, res.get().value);
 
     }