nfs4: set filesize on open if specified

Motivation:
In some cases, on create, clients might specify file's initial size.
Currently we support only zero size, which lets some synthetic test to
fail.

Modification:
Update OperationOPEN to set file size on create if specified.

Result:
Better spec compliance.

NOTE: as POSIX doesn't provide such functionality to applications, this
functionality use by special clients only.

Acked-by: Karen Hoyos
Target: master

Author: kofemann

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

@@ -169,7 +169,12 @@ public void process(CompoundContext context, nfs_resop4 result) throws ChimeraNF
                             res.resok4.attrset.set(nfs4_prot.FATTR4_MODE);
                         }
 
-                        if (createSize.isPresent() && createSize.get().value == 0) {
+                        if (createSize.isPresent()) {
+                            if (createSize.get().value != 0) {
+                                var newSizeStat = new Stat();
+                                newSizeStat.setSize(createSize.get().value);
+                                context.getFs().setattr(inode, newSizeStat);
+                            }
                             res.resok4.attrset.set(nfs4_prot.FATTR4_SIZE);
                         }