--- zzzz-none-000/linux-3.10.107/fs/nfs/mount_clnt.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/fs/nfs/mount_clnt.c	2021-02-04 17:41:59.000000000 +0000
@@ -16,9 +16,7 @@
 #include <linux/nfs_fs.h>
 #include "internal.h"
 
-#ifdef NFS_DEBUG
-# define NFSDBG_FACILITY	NFSDBG_MOUNT
-#endif
+#define NFSDBG_FACILITY	NFSDBG_MOUNT
 
 /*
  * Defined by RFC 1094, section A.3; and RFC 1813, section 5.1.4
@@ -139,7 +137,10 @@
  * nfs_mount - Obtain an NFS file handle for the given host and path
  * @info: pointer to mount request arguments
  *
- * Uses default timeout parameters specified by underlying transport.
+ * Uses default timeout parameters specified by underlying transport. On
+ * successful return, the auth_flavs list and auth_flav_len will be populated
+ * with the list from the server or a faked-up list if the server didn't
+ * provide one.
  */
 int nfs_mount(struct nfs_mount_request *info)
 {
@@ -195,6 +196,15 @@
 	dprintk("NFS: MNT request succeeded\n");
 	status = 0;
 
+	/*
+	 * If the server didn't provide a flavor list, allow the
+	 * client to try any flavor.
+	 */
+	if (info->version != NFS_MNT3_VERSION || *info->auth_flav_len == 0) {
+		dprintk("NFS: Faking up auth_flavs list\n");
+		info->auth_flavs[0] = RPC_AUTH_NULL;
+		*info->auth_flav_len = 1;
+	}
 out:
 	return status;