NFS: Return a real error code from mount(2)

Don't filter the return code from the in-kernel rpcbind or NFS mount
clients.  Return the real error code so that callers of the new NFS
text-based mount API can apply a useful retry strategy.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/super.c

@@ -1166,7 +1166,7 @@ static int nfs_validate_mount_data(struct nfs_mount_data **options,
 
 		status = nfs_try_mount(&args, mntfh);
 		if (status)
-			return -EINVAL;
+			return status;
 
 		/*
 		 * Translate to nfs_mount_data, which nfs_fill_super