Index: smbd/trans2.c
===================================================================
--- smbd/trans2.c	(revision 15718)
+++ smbd/trans2.c	(working copy)
@@ -860,7 +860,26 @@
 		return(ERROR_DOS(ERRDOS,ERRnoaccess));
 	}
 
-	if (total_data && smb_action == FILE_WAS_CREATED) {
+   /* allocate space for the file if a size hint is supplied */
+	if (smb_action != FILE_WAS_OPENED && open_size && (open_size > size)) /* in case of create or overwrite only */
+	{
+		fsp->initial_allocation_size = smb_roundup(fsp->conn, open_size);
+		size = open_size; /* Adjust size here to return the right size in the reply. At least Windows does it that way. */
+		
+		if (fsp->is_directory) {
+			close_file(fsp,False);
+			END_PROFILE(SMBntcreateX);
+			/* Can't set allocation size on a directory. */
+			return ERROR_NT(NT_STATUS_ACCESS_DENIED);
+		}
+		if (vfs_allocate_file_space(fsp, fsp->initial_allocation_size) == -1) {
+			close_file(fsp,False);
+			return ERROR_NT(NT_STATUS_DISK_FULL);
+		}
+	} else
+		fsp->initial_allocation_size = smb_roundup(fsp->conn, (SMB_BIG_UINT)size);
+
+	if (total_data && smb_action != FILE_WAS_OPENED) { /* in case of create or overwrite only */
 		status = set_ea(conn, fsp, fname, ea_list);
 		talloc_destroy(ctx);
 		if (!NT_STATUS_IS_OK(status)) {