xfs : fix build with trace enabled, improve error checks

- Remove referencing an undeclared identifier

    - Instead of an assert, just log an error for XFS V5 filesystems
      and don't try to mount them

Change-Id: I67303aff89b81a28b7333569fea8113b6020dc54
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5204
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>

src/add-ons/kernel/file_systems/xfs/Inode.cpp

@@ -301,7 +301,6 @@ Inode::GetNodefromTree(uint16& levelsInTree, Volume* volume,
 	ArrayDeleter<char> nodeDeleter(node);
 
 	TRACE("levels:(%d)\n", levelsInTree);
-	TRACE("Numrecs:(%d)\n", fRoot->NumRecords());
 
 	TreePointer* ptrToNode = GetPtrFromRoot(1);
 	uint64 fileSystemBlockNo = B_BENDIAN_TO_HOST_INT64(*ptrToNode);

src/add-ons/kernel/file_systems/xfs/xfs.cpp

@@ -25,7 +25,10 @@ XfsSuperBlock::IsValid() const
 	}
 
 	// Checking version 4 file system
-	ASSERT((Version() & 0x000f) == 4)
+	if ((Version() & 0x000f) > 4) {
+		ERROR("XFS version 5 or later is not yet supported");
+		return false;
+	}
 
 	return true;
 }