NFS: change NFS mount error return when hostname/pathname too long

According to the mount(2) man page, the proper error return code for the
mount(2) system call when the special device name or the mounted-on
directory name is too long is ENAMETOOLONG.

Signed-off-by: Chuck Lever <[e-mail]>
Signed-off-by: Trond Myklebust <[e-mail]>

fs/nfs/super.c

···
 			return -EINVAL;
 		len = c - dev_name;
 		if (len > sizeof(data->hostname))
-			return -EINVAL;
+			return -ENAMETOOLONG;
 		strncpy(data->hostname, dev_name, len);
 		args.nfs_server.hostname = data->hostname;
 
 		c++;
 		if (strlen(c) > NFS_MAXPATHLEN)
-			return -EINVAL;
+			return -ENAMETOOLONG;
 		args.nfs_server.export_path = c;
 
 		status = nfs_try_mount(&args, mntfh);
···
 		/* while calculating len, pretend ':' is '\0' */
 		len = c - dev_name;
 		if (len > NFS4_MAXNAMLEN)
-			return -EINVAL;
+			return -ENAMETOOLONG;
 		*hostname = kzalloc(len, GFP_KERNEL);
 		if (*hostname == NULL)
 			return -ENOMEM;
···
 		c++;			/* step over the ':' */
 		len = strlen(c);
 		if (len > NFS4_MAXPATHLEN)
-			return -EINVAL;
+			return -ENAMETOOLONG;
 		*mntpath = kzalloc(len + 1, GFP_KERNEL);
 		if (*mntpath == NULL)
 			return -ENOMEM;