diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
index 4537a8f..323cbdc 100644
--- a/fs/nfsd/export.c
+++ b/fs/nfsd/export.c
@@ -1228,6 +1228,28 @@
 	return exp;
 }
 
+__be32 check_nfsd_access(struct svc_export *exp, struct svc_rqst *rqstp)
+{
+	struct exp_flavor_info *f;
+	struct exp_flavor_info *end = exp->ex_flavors + exp->ex_nflavors;
+
+	/* legacy gss-only clients are always OK: */
+	if (exp->ex_client == rqstp->rq_gssclient)
+		return 0;
+	/* ip-address based client; check sec= export option: */
+	for (f = exp->ex_flavors; f < end; f++) {
+		if (f->pseudoflavor == rqstp->rq_flavor)
+			return 0;
+	}
+	/* defaults in absence of sec= options: */
+	if (exp->ex_nflavors == 0) {
+		if (rqstp->rq_flavor == RPC_AUTH_NULL ||
+		    rqstp->rq_flavor == RPC_AUTH_UNIX)
+			return 0;
+	}
+	return nfserr_wrongsec;
+}
+
 /*
  * Uses rq_client and rq_gssclient to find an export; uses rq_client (an
  * auth_unix client) if it's available and has secinfo information;
@@ -1340,6 +1362,10 @@
 	if (IS_ERR(exp))
 		return nfserrno(PTR_ERR(exp));
 	rv = fh_compose(fhp, exp, exp->ex_dentry, NULL);
+	if (rv)
+		goto out;
+	rv = check_nfsd_access(exp, rqstp);
+out:
 	exp_put(exp);
 	return rv;
 }
diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c
index 22cb5be..d5fe392 100644
--- a/fs/nfsd/nfsfh.c
+++ b/fs/nfsd/nfsfh.c
@@ -20,6 +20,7 @@
 
 #include <linux/sunrpc/clnt.h>
 #include <linux/sunrpc/svc.h>
+#include <linux/sunrpc/svcauth_gss.h>
 #include <linux/nfsd/nfsd.h>
 
 #define NFSDDBG_FACILITY		NFSDDBG_FH
@@ -248,6 +249,11 @@
 	if (error)
 		goto out;
 
+	/* Check security flavor */
+	error = check_nfsd_access(exp, rqstp);
+	if (error)
+		goto out;
+
 	/* Finally, check access permissions. */
 	error = nfsd_permission(exp, dentry, access);
 
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 5c8192b..a8c89ae 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -494,6 +494,15 @@
 	module_put_and_exit(0);
 }
 
+static __be32 map_new_errors(u32 vers, __be32 nfserr)
+{
+	if (nfserr == nfserr_jukebox && vers == 2)
+		return nfserr_dropit;
+	if (nfserr == nfserr_wrongsec && vers < 4)
+		return nfserr_acces;
+	return nfserr;
+}
+
 int
 nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
 {
@@ -536,6 +545,7 @@
 
 	/* Now call the procedure handler, and encode NFS status. */
 	nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
+	nfserr = map_new_errors(rqstp->rq_vers, nfserr);
 	if (nfserr == nfserr_jukebox && rqstp->rq_vers == 2)
 		nfserr = nfserr_dropit;
 	if (nfserr == nfserr_dropit) {
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 627f460..8e109e5 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -240,6 +240,9 @@
 	err = nfsd_lookup_dentry(rqstp, fhp, name, len, &exp, &dentry);
 	if (err)
 		return err;
+	err = check_nfsd_access(exp, rqstp);
+	if (err)
+		goto out;
 	/*
 	 * Note: we compose the file handle now, but as the
 	 * dentry may be negative, it may need to be updated.
@@ -247,6 +250,7 @@
 	err = fh_compose(resfh, exp, dentry, fhp);
 	if (!err && !dentry->d_inode)
 		err = nfserr_noent;
+out:
 	dput(dentry);
 	exp_put(exp);
 	return err;