[PATCH 3.14 85/88] svcrdma: Select NFSv4.1 backchannel transport based on forward channel

Greg Kroah-Hartman
2014-09-03T23:25:40Z

From: Chuck Lever <chuck.lever@oracle.com>

commit 3c45ddf823d679a820adddd53b52c6699c9a05ac upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/nfsd/nfs4callback.c | 3 ++-
include/linux/sunrpc/svc_xprt.h | 1 +
net/sunrpc/svcsock.c | 2 ++
net/sunrpc/xprt.c | 2 +-
net/sunrpc/xprtrdma/svc_rdma_transport.c | 1 +
5 files changed, 7 insertions(+), 2 deletions(-)

--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -672,7 +672,8 @@ static int setup_callback_client(struct
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 */
--- a/include/linux/sunrpc/svc_xprt.h
+++ b/include/linux/sunrpc/svc_xprt.h
@@ -32,6 +32,7 @@ struct svc_xprt_class {
struct svc_xprt_ops *xcl_ops;
struct list_head xcl_list;
u32 xcl_max_payload;
+ int xcl_ident;
};

/*
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -685,6 +685,7 @@ static struct svc_xprt_class svc_udp_cla
.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)
@@ -1279,6 +1280,7 @@ static struct svc_xprt_class svc_tcp_cla
.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)
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1316,7 +1316,7 @@ struct rpc_xprt *xprt_create_transport(s
}
}
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:
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -89,6 +89,7 @@ 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)