svcrdma: Select NFSv4.1 backchannel transport based on forward channel

The current code always selects XPRT_TRANSPORT_BC_TCP for the back
channel, even when the forward channel was not TCP (eg, RDMA). When
a 4.1 mount is attempted with RDMA, the server panics in the TCP BC
code when trying to send CB_NULL.

Instead, construct the transport protocol number from the forward
channel transport or'd with XPRT_TRANSPORT_BC. Transports that do
not support bi-directional RPC will not have registered a "BC"
transport, causing create_backchannel_client() to fail immediately.

Fixes: https://bugzilla.linux-nfs.org/show_bug.cgi?id=265
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index a88a93e..564d723 100644 (file)
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -689,7 +689,8 @@ static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *c
                clp->cl_cb_session = ses;
                args.bc_xprt = conn->cb_xprt;
                args.prognumber = clp->cl_cb_session->se_cb_prog;
-               args.protocol = XPRT_TRANSPORT_BC_TCP;
+               args.protocol = conn->cb_xprt->xpt_class->xcl_ident |
+                               XPRT_TRANSPORT_BC;
                args.authflavor = ses->se_cb_sec.flavor;
        }
        /* Create RPC client */

diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h
index 7235040..5d9d6f8 100644 (file)
--- a/include/linux/sunrpc/svc_xprt.h
+++ b/include/linux/sunrpc/svc_xprt.h
@@ -33,6 +33,7 @@ struct svc_xprt_class {
        struct svc_xprt_ops     *xcl_ops;
        struct list_head        xcl_list;
        u32                     xcl_max_payload;
+       int                     xcl_ident;
 };
 
 /*

diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index b507cd3..b2437ee 100644 (file)
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -692,6 +692,7 @@ static struct svc_xprt_class svc_udp_class = {
        .xcl_owner = THIS_MODULE,
        .xcl_ops = &svc_udp_ops,
        .xcl_max_payload = RPCSVC_MAXPAYLOAD_UDP,
+       .xcl_ident = XPRT_TRANSPORT_UDP,
 };
 
 static void svc_udp_init(struct svc_sock *svsk, struct svc_serv *serv)
@@ -1292,6 +1293,7 @@ static struct svc_xprt_class svc_tcp_class = {
        .xcl_owner = THIS_MODULE,
        .xcl_ops = &svc_tcp_ops,
        .xcl_max_payload = RPCSVC_MAXPAYLOAD_TCP,
+       .xcl_ident = XPRT_TRANSPORT_TCP,
 };
 
 void svc_init_xprt_sock(void)

diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index c3b2b33..51c6316 100644 (file)
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1306,7 +1306,7 @@ struct rpc_xprt *xprt_create_transport(struct xprt_create *args)
                }
        }
        spin_unlock(&xprt_list_lock);
-       printk(KERN_ERR "RPC: transport (%d) not supported\n", args->ident);
+       dprintk("RPC: transport (%d) not supported\n", args->ident);
        return ERR_PTR(-EIO);
 
 found:

diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index e7323fb..06a5d92 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -92,6 +92,7 @@ struct svc_xprt_class svc_rdma_class = {
        .xcl_owner = THIS_MODULE,
        .xcl_ops = &svc_rdma_ops,
        .xcl_max_payload = RPCSVC_MAXPAYLOAD_TCP,
+       .xcl_ident = XPRT_TRANSPORT_RDMA,
 };
 
 struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *xprt)