@@ -595,6 +595,87 @@ out_major_mismatch:
return false;
}
+/*
+ * Returns true if server minor ids match
+ */
+static bool
+nfs4_check_serverowner_minor_id(struct nfs41_server_owner *o1,
+ struct nfs41_server_owner *o2)
+{
+ /* Check eir_server_owner so_minor_id */
+ if (o1->minor_id != o2->minor_id)
+ goto out_minor_mismatch;
+
+ dprintk("NFS: --> %s server owner minor IDs s match\n", __func__);
+ return true;
+
+out_minor_mismatch:
+ dprintk("NFS: --> %s server owner minor IDs do not match\n", __func__);
+ return false;
+}
+
+/*
+ * Returns true if the server scopes match
+ */
+static bool
+nfs4_check_server_scope(struct nfs41_server_scope *s1,
+ struct nfs41_server_scope *s2)
+{
+ if (s1->server_scope_sz != s2->server_scope_sz)
+ goto out_scope_mismatch;
+ if (memcmp(s1->server_scope, s2->server_scope,
+ s1->server_scope_sz) != 0)
+ goto out_scope_mismatch;
+
+ dprintk("NFS: --> %s server scopes match\n", __func__);
+ return true;
+
+out_scope_mismatch:
+ dprintk("NFS: --> %s server scopes do not match\n",
+ __func__);
+ return false;
+}
+
+/**
+ * nfs4_detect_session_trunking - Checks for ssession trunking called
+ * after a successuful EXCHANGE_ID testing a multi-addr connection to be
+ * potentially added as a session trunk
+ *
+ * @clp: original mount nfs_client
+ * @res: result structure from an exchange_id using the original mount
+ * nfs_client with a new multi_addr transport
+ *
+ * Returns zero on success, otherwise -EINVAL
+ *
+ * Note: since the exchange_id for the new multi_addr transport uses the
+ * same nfs_client from the original mount, the cl_owner_id is reused,
+ * so eir_clientowner is the same.
+ */
+int nfs4_detect_session_trunking(struct nfs_client *clp,
+ struct nfs41_exchange_id_res *res)
+{
+
+ /* Check eir_clientid */
+ if (!nfs4_match_clientids(clp->cl_clientid, res->clientid))
+ return -EINVAL;
+
+ /* Check eir_server_owner so_major_id */
+ if (!nfs4_check_serverowner_major_id(clp->cl_serverowner,
+ res->server_owner))
+ return -EINVAL;
+
+ /* Check eir_server_owner so_minor_id */
+ if (!nfs4_check_serverowner_minor_id(clp->cl_serverowner,
+ res->server_owner))
+ return -EINVAL;
+
+ /* Check eir_server_scope */
+ if (!nfs4_check_server_scope(clp->cl_serverscope, res->server_scope))
+ return -EINVAL;
+
+ return 0;
+}
+
/**
* nfs41_walk_client_list - Find nfs_client that matches a client/server owner
*