Merge branch 'multipath'

* multipath:
  NFS add callback_ops to nfs4_proc_bind_conn_to_session_callback
  pnfs/NFSv4.1: Add multipath capabilities to pNFS flexfiles servers over NFSv3
  SUNRPC: Allow addition of new transports to a struct rpc_clnt
  NFSv4.1: nfs4_proc_bind_conn_to_session must iterate over all connections
  SUNRPC: Make NFS swap work with multipath
  SUNRPC: Add a helper to apply a function to all the rpc_clnt's transports
  SUNRPC: Allow caller to specify the transport to use
  SUNRPC: Use the multipath iterator to assign a transport to each task
  SUNRPC: Make rpc_clnt store the multipath iterators
  SUNRPC: Add a structure to track multiple transports
  SUNRPC: Make freeing of struct xprt rcu-safe
  SUNRPC: Uninline xprt_get(); It isn't performance critical.
  SUNRPC: Reorder rpc_task to put waitqueue related info in same cachelines
  SUNRPC: Remove unused function rpc_task_reset_client

2 files changed, 71 insertions, 6 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 1e103b4f4ad7..c70de30b80f1 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -6782,13 +6782,26 @@ nfs41_same_server_scope(struct nfs41_server_scope *a,
         return false;
 }
 
+static void
+nfs4_bind_one_conn_to_session_done(struct rpc_task *task, void *calldata)
+{
+}
+
+static const struct rpc_call_ops nfs4_bind_one_conn_to_session_ops = {
+        .rpc_call_done =  &nfs4_bind_one_conn_to_session_done,
+};
+
 /*
- * nfs4_proc_bind_conn_to_session()
+ * nfs4_proc_bind_one_conn_to_session()
  *
  * The 4.1 client currently uses the same TCP connection for the
  * fore and backchannel.
  */
-int nfs4_proc_bind_conn_to_session(struct nfs_client *clp, struct rpc_cred *cred)
+static
+int nfs4_proc_bind_one_conn_to_session(struct rpc_clnt *clnt,
+                struct rpc_xprt *xprt,
+                struct nfs_client *clp,
+                struct rpc_cred *cred)
 {
         int status;
         struct nfs41_bind_conn_to_session_args args = {
@@ -6803,6 +6816,14 @@ int nfs4_proc_bind_conn_to_session(struct nfs_client *clp, struct rpc_cred *cred
                 .rpc_resp = &res,
                 .rpc_cred = cred,
         };
+        struct rpc_task_setup task_setup_data = {
+                .rpc_client = clnt,
+                .rpc_xprt = xprt,
+                .callback_ops = &nfs4_bind_one_conn_to_session_ops,
+                .rpc_message = &msg,
+                .flags = RPC_TASK_TIMEOUT,
+        };
+        struct rpc_task *task;
 
         dprintk("--> %s\n", __func__);
 
@@ -6810,7 +6831,16 @@ int nfs4_proc_bind_conn_to_session(struct nfs_client *clp, struct rpc_cred *cred
         if (!(clp->cl_session->flags & SESSION4_BACK_CHAN))
                 args.dir = NFS4_CDFC4_FORE;
 
-        status = rpc_call_sync(clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
+        /* Do not set the backchannel flag unless this is clnt->cl_xprt */
+        if (xprt != rcu_access_pointer(clnt->cl_xprt))
+                args.dir = NFS4_CDFC4_FORE;
+
+        task = rpc_run_task(&task_setup_data);
+        if (!IS_ERR(task)) {
+                status = task->tk_status;
+                rpc_put_task(task);
+        } else
+                status = PTR_ERR(task);
         trace_nfs4_bind_conn_to_session(clp, status);
         if (status == 0) {
                 if (memcmp(res.sessionid.data,
@@ -6837,6 +6867,31 @@ out:
         return status;
 }
 
+struct rpc_bind_conn_calldata {
+        struct nfs_client *clp;
+        struct rpc_cred *cred;
+};
+
+static int
+nfs4_proc_bind_conn_to_session_callback(struct rpc_clnt *clnt,
+                struct rpc_xprt *xprt,
+                void *calldata)
+{
+        struct rpc_bind_conn_calldata *p = calldata;
+
+        return nfs4_proc_bind_one_conn_to_session(clnt, xprt, p->clp, p->cred);
+}
+
+int nfs4_proc_bind_conn_to_session(struct nfs_client *clp, struct rpc_cred *cred)
+{
+        struct rpc_bind_conn_calldata data = {
+                .clp = clp,
+                .cred = cred,
+        };
+        return rpc_clnt_iterate_for_each_xprt(clp->cl_rpcclient,
+                        nfs4_proc_bind_conn_to_session_callback, &data);
+}
+
 /*
  * Minimum set of SP4_MACH_CRED operations from RFC 5661 in the enforce map
  * and operations we'd like to see to enable certain features in the allow map
diff --git a/fs/nfs/pnfs_nfs.c b/fs/nfs/pnfs_nfs.c
index 81ac6480f9e7..4aaed890048f 100644
--- a/fs/nfs/pnfs_nfs.c
+++ b/fs/nfs/pnfs_nfs.c
@@ -606,12 +606,22 @@ static int _nfs4_pnfs_v3_ds_connect(struct nfs_server *mds_srv,
                 dprintk("%s: DS %s: trying address %s\n",
                         __func__, ds->ds_remotestr, da->da_remotestr);
 
-                clp = get_v3_ds_connect(mds_srv->nfs_client,
+                if (!IS_ERR(clp)) {
+                        struct xprt_create xprt_args = {
+                                .ident = XPRT_TRANSPORT_TCP,
+                                .net = clp->cl_net,
+                                .dstaddr = (struct sockaddr *)&da->da_addr,
+                                .addrlen = da->da_addrlen,
+                                .servername = clp->cl_hostname,
+                        };
+                        /* Add this address as an alias */
+                        rpc_clnt_add_xprt(clp->cl_rpcclient, &xprt_args,
+                                        rpc_clnt_test_and_add_xprt, NULL);
+                } else
+                        clp = get_v3_ds_connect(mds_srv->nfs_client,
                                         (struct sockaddr *)&da->da_addr,
                                         da->da_addrlen, IPPROTO_TCP,
                                         timeo, retrans, au_flavor);
-                if (!IS_ERR(clp))
-                        break;
         }
 
         if (IS_ERR(clp)) {