Don't log expected error on DFS referral request

STATUS_FS_DRIVER_REQUIRED is expected when DFS is not turned
on on the server.  Do not log it on DFS referral response.
It clutters the dmesg log unnecessarily at mount time.

Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com
Reviewed-by: Ronnie sahlberg <lsahlber@redhat.com>

fs/cifs/smb2maperror.c

@@ -745,7 +745,7 @@ static const struct status_to_posix_error smb2_error_map_table[] = {
 	"STATUS_NOLOGON_SERVER_TRUST_ACCOUNT"},
 	{STATUS_DOMAIN_TRUST_INCONSISTENT, -EIO,
 	"STATUS_DOMAIN_TRUST_INCONSISTENT"},
-	{STATUS_FS_DRIVER_REQUIRED, -EIO, "STATUS_FS_DRIVER_REQUIRED"},
+	{STATUS_FS_DRIVER_REQUIRED, -EOPNOTSUPP, "STATUS_FS_DRIVER_REQUIRED"},
 	{STATUS_IMAGE_ALREADY_LOADED_AS_DLL, -EIO,
 	"STATUS_IMAGE_ALREADY_LOADED_AS_DLL"},
 	{STATUS_NETWORK_OPEN_RESTRICTION, -EIO,

fs/cifs/smb2ops.c

@@ -1412,7 +1412,7 @@ smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses,
 	} while (rc == -EAGAIN);
 
 	if (rc) {
-		if (rc != -ENOENT)
+		if ((rc != -ENOENT) && (rc != -EOPNOTSUPP))
 			cifs_dbg(VFS, "ioctl error in smb2_get_dfs_refer rc=%d\n", rc);
 		goto out;
 	}