NFSD/SUNRPC: Check rpc_xprt out of xs_setup_bc_tcp

Besides checking rpc_xprt out of xs_setup_bc_tcp,
increase it's reference (it's important).

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 7f05cd1..39c8ef8 100644 (file)
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -32,6 +32,7 @@
  */
 
 #include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/xprt.h>
 #include <linux/sunrpc/svc_xprt.h>
 #include <linux/slab.h>
 #include "nfsd.h"
@@ -635,6 +636,22 @@ static struct rpc_cred *get_backchannel_cred(struct nfs4_client *clp, struct rpc
        }
 }
 
+static struct rpc_clnt *create_backchannel_client(struct rpc_create_args *args)
+{
+       struct rpc_xprt *xprt;
+
+       if (args->protocol != XPRT_TRANSPORT_BC_TCP)
+               return rpc_create(args);
+
+       xprt = args->bc_xprt->xpt_bc_xprt;
+       if (xprt) {
+               xprt_get(xprt);
+               return rpc_create_xprt(args, xprt);
+       }
+
+       return rpc_create(args);
+}
+
 static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
 {
        struct rpc_timeout      timeparms = {
@@ -674,7 +691,7 @@ static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *c
                args.authflavor = ses->se_cb_sec.flavor;
        }
        /* Create RPC client */
-       client = rpc_create(&args);
+       client = create_backchannel_client(&args);
        if (IS_ERR(client)) {
                dprintk("NFSD: couldn't create callback client: %ld\n",
                        PTR_ERR(client));

diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index 8097b9d..3e5efb2 100644 (file)
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -295,13 +295,24 @@ int                       xprt_adjust_timeout(struct rpc_rqst *req);
 void                   xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
 void                   xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
 void                   xprt_release(struct rpc_task *task);
-struct rpc_xprt *      xprt_get(struct rpc_xprt *xprt);
 void                   xprt_put(struct rpc_xprt *xprt);
 struct rpc_xprt *      xprt_alloc(struct net *net, size_t size,
                                unsigned int num_prealloc,
                                unsigned int max_req);
 void                   xprt_free(struct rpc_xprt *);
 
+/**
+ * xprt_get - return a reference to an RPC transport.
+ * @xprt: pointer to the transport
+ *
+ */
+static inline struct rpc_xprt *xprt_get(struct rpc_xprt *xprt)
+{
+       if (atomic_inc_not_zero(&xprt->count))
+               return xprt;
+       return NULL;
+}
+
 static inline __be32 *xprt_skip_transport_header(struct rpc_xprt *xprt, __be32 *p)
 {
        return p + xprt->tsh_size;

diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 7d4df99..d173f79 100644 (file)
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1383,15 +1383,3 @@ void xprt_put(struct rpc_xprt *xprt)
        if (atomic_dec_and_test(&xprt->count))
                xprt_destroy(xprt);
 }
-
-/**
- * xprt_get - return a reference to an RPC transport.
- * @xprt: pointer to the transport
- *
- */
-struct rpc_xprt *xprt_get(struct rpc_xprt *xprt)
-{
-       if (atomic_inc_not_zero(&xprt->count))
-               return xprt;
-       return NULL;
-}

diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 63ae657..1335239 100644 (file)
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -2923,15 +2923,6 @@ static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args)
        struct svc_sock *bc_sock;
        struct rpc_xprt *ret;
 
-       if (args->bc_xprt->xpt_bc_xprt) {
-               /*
-                * This server connection already has a backchannel
-                * transport; we can't create a new one, as we wouldn't
-                * be able to match replies based on xid any more.  So,
-                * reuse the already-existing one:
-                */
-                return args->bc_xprt->xpt_bc_xprt;
-       }
        xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
                        xprt_tcp_slot_table_entries);
        if (IS_ERR(xprt))