NFSv4: Allow multiple connections to NFSv4.x (x>0) servers

If the user specifies the -onconn=<number> mount option, and the transport
protocol is TCP, then set up <number> connections to the server. The
connections will all go to the same IP address.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

4 files changed, 13 insertions, 2 deletions

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index d7e4f0848e28..fa6953e56a71 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -175,6 +175,7 @@ struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *cl_init)
         clp->cl_rpcclient = ERR_PTR(-EINVAL);
 
         clp->cl_proto = cl_init->proto;
+        clp->cl_nconnect = cl_init->nconnect;
         clp->cl_net = get_net(cl_init->net);
 
         clp->cl_principal = "*";
@@ -493,6 +494,7 @@ int nfs_create_rpc_client(struct nfs_client *clp,
         struct rpc_create_args args = {
                 .net            = clp->cl_net,
                 .protocol       = clp->cl_proto,
+                .nconnect       = clp->cl_nconnect,
                 .address        = (struct sockaddr *)&clp->cl_addr,
                 .addrsize       = clp->cl_addrlen,
                 .timeout        = cl_init->timeparms,
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index bba09dace5d6..4a49dc1495c5 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -82,6 +82,7 @@ struct nfs_client_initdata {
         struct nfs_subversion *nfs_mod;
         int proto;
         u32 minorversion;
+        unsigned int nconnect;
         struct net *net;
         const struct rpc_timeout *timeparms;
         const struct cred *cred;
diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
index 81b9b6d7927a..5c244c440658 100644
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -859,7 +859,8 @@ static int nfs4_set_client(struct nfs_server *server,
                 const size_t addrlen,
                 const char *ip_addr,
                 int proto, const struct rpc_timeout *timeparms,
-                u32 minorversion, struct net *net)
+                u32 minorversion, unsigned int nconnect,
+                struct net *net)
 {
         struct nfs_client_initdata cl_init = {
                 .hostname = hostname,
@@ -875,6 +876,8 @@ static int nfs4_set_client(struct nfs_server *server,
         };
         struct nfs_client *clp;
 
+        if (minorversion > 0 && proto == XPRT_TRANSPORT_TCP)
+                cl_init.nconnect = nconnect;
         if (server->flags & NFS_MOUNT_NORESVPORT)
                 set_bit(NFS_CS_NORESVPORT, &cl_init.init_flags);
         if (server->options & NFS_OPTION_MIGRATION)
@@ -1074,6 +1077,7 @@ static int nfs4_init_server(struct nfs_server *server,
                         data->nfs_server.protocol,
                         &timeparms,
                         data->minorversion,
+                        data->nfs_server.nconnect,
                         data->net);
         if (error < 0)
                 return error;
@@ -1163,6 +1167,7 @@ struct nfs_server *nfs4_create_referral_server(struct nfs_clone_mount *data,
                                 XPRT_TRANSPORT_RDMA,
                                 parent_server->client->cl_timeout,
                                 parent_client->cl_mvops->minor_version,
+                                parent_client->cl_nconnect,
                                 parent_client->cl_net);
         if (!error)
                 goto init_server;
@@ -1176,6 +1181,7 @@ struct nfs_server *nfs4_create_referral_server(struct nfs_clone_mount *data,
                                 XPRT_TRANSPORT_TCP,
                                 parent_server->client->cl_timeout,
                                 parent_client->cl_mvops->minor_version,
+                                parent_client->cl_nconnect,
                                 parent_client->cl_net);
         if (error < 0)
                 goto error;
@@ -1271,7 +1277,8 @@ int nfs4_update_server(struct nfs_server *server, const char *hostname,
         set_bit(NFS_MIG_TSM_POSSIBLE, &server->mig_status);
         error = nfs4_set_client(server, hostname, sap, salen, buf,
                                 clp->cl_proto, clnt->cl_timeout,
-                                clp->cl_minorversion, net);
+                                clp->cl_minorversion,
+                                clp->cl_nconnect, net);
         clear_bit(NFS_MIG_TSM_POSSIBLE, &server->mig_status);
         if (error != 0) {
                 nfs_server_insert_lists(server);
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index 1e78032a174b..a87fe854f008 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -58,6 +58,7 @@ struct nfs_client {
         struct nfs_subversion * cl_nfs_mod;     /* pointer to nfs version module */
 
         u32                     cl_minorversion;/* NFSv4 minorversion */
+        unsigned int            cl_nconnect;    /* Number of connections */
         const char *            cl_principal;  /* used for machine cred */
 
 #if IS_ENABLED(CONFIG_NFS_V4)