--- linux-2.6.16.x86_64/fs/nfsd/vfs.c.org
+++ linux-2.6.16.x86_64/fs/nfsd/vfs.c
@@ -327,6 +327,11 @@ nfsd_setattr(struct svc_rqst *rqstp, str
 			goto out_nfserr;
 		}
 		DQUOT_INIT(inode);
+		/*
+		 * Make sure that the mtime changes even if the file
+		 * size doesn't actually change.
+		 */
+		iap->ia_valid |= ATTR_MTIME | ATTR_CTIME;
 	}
 
 	imode = inode->i_mode;