NFSv4.2: fix handling of COPY ERR_OFFLOAD_NO_REQ

[ Upstream commit 5690eed ]

If the client sent a synchronous copy and the server replied with
ERR_OFFLOAD_NO_REQ indicating that it wants an asynchronous
copy instead, the client should retry with asynchronous copy.

Fixes: 539f57b ("NFS handle COPY ERR_OFFLOAD_NO_REQS")
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

fs/nfs/nfs42proc.c

@@ -470,8 +470,9 @@ ssize_t nfs42_proc_copy(struct file *src, loff_t pos_src,
 				continue;
 			}
 			break;
-		} else if (err == -NFS4ERR_OFFLOAD_NO_REQS && !args.sync) {
-			args.sync = true;
+		} else if (err == -NFS4ERR_OFFLOAD_NO_REQS &&
+				args.sync != res.synchronous) {
+			args.sync = res.synchronous;
 			dst_exception.retry = 1;
 			continue;
 		} else if ((err == -ESTALE ||