nfsd: handle EUCLEAN

Eric Sandeen reports that xfs can return this if filesystem corruption
prevented completing the operation.

Reported-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfsproc.c

@@ -791,6 +791,7 @@ nfserrno (int errno)
 		{ nfserr_toosmall, -ETOOSMALL },
 		{ nfserr_serverfault, -ESERVERFAULT },
 		{ nfserr_serverfault, -ENFILE },
+		{ nfserr_io, -EUCLEAN },
 	};
 	int	i;