nfs: Referrals should use the same proto setting as their parent

Helen Chao <helen.chao@oracle.com> noticed that when a user
traverses a referral on an NFS/RDMA mount, the resulting submount
always uses TCP.

This behavior does not match the vers= setting when traversing
a referral (vers=4.1 is preserved). It also does not match the
behavior of crossing from the pseudofs into a real filesystem
(proto=rdma is preserved in that case).

The Linux NFS client does not currently support the
fs_locations_info attribute. The situation is similar for all
NFSv4 servers I know of. Therefore until the community has broad
support for fs_locations_info, when following a referral:

 - First try to connect with RPC-over-RDMA. This will fail quickly
   if the client has no RDMA-capable interfaces.

 - If connecting with RPC-over-RDMA fails, or the RPC-over-RDMA
   transport is not available, use TCP.

Reported-by: Helen Chao <helen.chao@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
index 65a7e5da508c3e3019dab617b3ba92521b96cd0b..507f1f534b164291edf3b71e4868928817a3c219 100644 (file)
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -1123,19 +1123,36 @@ struct nfs_server *nfs4_create_referral_server(struct nfs_clone_mount *data,
        /* Initialise the client representation from the parent server */
        nfs_server_copy_userdata(server, parent_server);
 
-       /* Get a client representation.
-        * Note: NFSv4 always uses TCP, */
+       /* Get a client representation */
+#ifdef CONFIG_SUNRPC_XPRT_RDMA
+       rpc_set_port(data->addr, NFS_RDMA_PORT);
        error = nfs4_set_client(server, data->hostname,
                                data->addr,
                                data->addrlen,
                                parent_client->cl_ipaddr,
-                               rpc_protocol(parent_server->client),
+                               XPRT_TRANSPORT_RDMA,
+                               parent_server->client->cl_timeout,
+                               parent_client->cl_mvops->minor_version,
+                               parent_client->cl_net);
+       if (!error)
+               goto init_server;
+#endif /* CONFIG_SUNRPC_XPRT_RDMA */
+
+       rpc_set_port(data->addr, NFS_PORT);
+       error = nfs4_set_client(server, data->hostname,
+                               data->addr,
+                               data->addrlen,
+                               parent_client->cl_ipaddr,
+                               XPRT_TRANSPORT_TCP,
                                parent_server->client->cl_timeout,
                                parent_client->cl_mvops->minor_version,
                                parent_client->cl_net);
        if (error < 0)
                goto error;
 
+#ifdef CONFIG_SUNRPC_XPRT_RDMA
+init_server:
+#endif
        error = nfs_init_server_rpcclient(server, parent_server->client->cl_timeout, data->authflavor);
        if (error < 0)
                goto error;

diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
index 8c3f327d858d57ab5bbd519b929b26a7ecaee8dc..24f06dcc2b08eeabd9f6b14591584cf8676749c8 100644 (file)
--- a/fs/nfs/nfs4namespace.c
+++ b/fs/nfs/nfs4namespace.c
@@ -270,8 +270,6 @@ static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
                if (mountdata->addrlen == 0)
                        continue;
 
-               rpc_set_port(mountdata->addr, NFS_PORT);
-
                memcpy(page2, buf->data, buf->len);
                page2[buf->len] = '\0';
                mountdata->hostname = page2;