diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 8112ce8f4b230eaa46d5b0d77df05f2cbcd55343..e771a1a7c6f12c3b918c9201e51c4b3edefc5a9b 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -1663,6 +1663,14 @@ nfsd4_decode_compound(struct nfsd4_compoundargs *argp)
 			readbytes += nfsd4_max_reply(argp->rqstp, op);
 		} else
 			max_reply += nfsd4_max_reply(argp->rqstp, op);
+		/*
+		 * OP_LOCK may return a conflicting lock.  (Special case
+		 * because it will just skip encoding this if it runs
+		 * out of xdr buffer space, and it is the only operation
+		 * that behaves this way.)
+		 */
+		if (op->opnum == OP_LOCK)
+			max_reply += NFS4_OPAQUE_LIMIT;
 
 		if (op->status) {
 			argp->opcnt = i+1;