NFSv4.2 fix kfree in __nfs42_copy_file_range

This is triggering problems with static analysis with Coverity

Reported-by: Colin King <colin.king@netapp.com>
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
index b054d57..ef8c167 100644
--- a/fs/nfs/nfs4file.c
+++ b/fs/nfs/nfs4file.c
@@ -177,7 +177,8 @@ static ssize_t __nfs4_copy_file_range(struct file *file_in, loff_t pos_in,
 	ret = nfs42_proc_copy(file_in, pos_in, file_out, pos_out, count,
 				nss, cnrs, sync);
 out:
-	kfree(cn_resp);
+	if (!nfs42_files_from_same_server(file_in, file_out))
+		kfree(cn_resp);
 	if (ret == -EAGAIN)
 		goto retry;
 	return ret;