NFS pnfs data server multipath session trunking

Try all multipath addresses for a data server. The first address that
successfully connects and creates a session is the DS mount address.
All subsequent addresses are tested for session trunking and
added as aliases.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1 files changed, 33 insertions, 0 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index a70a972eb06f..cfdf45a14cc3 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -7353,6 +7353,37 @@ int nfs4_proc_exchange_id(struct nfs_client *clp, struct rpc_cred *cred)
 	return _nfs4_proc_exchange_id(clp, cred, SP4_NONE, NULL);
 }
 
+/**
+ * nfs4_test_session_trunk
+ *
+ * This is an add_xprt_test() test function called from
+ * rpc_clnt_setup_test_and_add_xprt.
+ *
+ * The rpc_xprt_switch is referrenced by rpc_clnt_setup_test_and_add_xprt
+ * and is dereferrenced in nfs4_exchange_id_release
+ *
+ * Upon success, add the new transport to the rpc_clnt
+ *
+ * @clnt: struct rpc_clnt to get new transport
+ * @xprt: the rpc_xprt to test
+ * @data: call data for _nfs4_proc_exchange_id.
+ */
+int nfs4_test_session_trunk(struct rpc_clnt *clnt, struct rpc_xprt *xprt,
+			    void *data)
+{
+	struct nfs4_add_xprt_data *adata = (struct nfs4_add_xprt_data *)data;
+	u32 sp4_how;
+
+	dprintk("--> %s try %s\n", __func__,
+		xprt->address_strings[RPC_DISPLAY_ADDR]);
+
+	sp4_how = (adata->clp->cl_sp4_flags == 0 ? SP4_NONE : SP4_MACH_CRED);
+
+	/* Test connection for session trunking. Async exchange_id call */
+	return  _nfs4_proc_exchange_id(adata->clp, adata->cred, sp4_how, xprt);
+}
+EXPORT_SYMBOL_GPL(nfs4_test_session_trunk);
+
 static int _nfs4_proc_destroy_clientid(struct nfs_client *clp,
 		struct rpc_cred *cred)
 {
@@ -8944,6 +8975,7 @@ static const struct nfs4_minor_version_ops nfs_v4_1_minor_ops = {
 	.find_root_sec = nfs41_find_root_sec,
 	.free_lock_state = nfs41_free_lock_state,
 	.alloc_seqid = nfs_alloc_no_seqid,
+	.session_trunk = nfs4_test_session_trunk,
 	.call_sync_ops = &nfs41_call_sync_ops,
 	.reboot_recovery_ops = &nfs41_reboot_recovery_ops,
 	.nograce_recovery_ops = &nfs41_nograce_recovery_ops,
@@ -8973,6 +9005,7 @@ static const struct nfs4_minor_version_ops nfs_v4_2_minor_ops = {
 	.free_lock_state = nfs41_free_lock_state,
 	.call_sync_ops = &nfs41_call_sync_ops,
 	.alloc_seqid = nfs_alloc_no_seqid,
+	.session_trunk = nfs4_test_session_trunk,
 	.reboot_recovery_ops = &nfs41_reboot_recovery_ops,
 	.nograce_recovery_ops = &nfs41_nograce_recovery_ops,
 	.state_renewal_ops = &nfs41_state_renewal_ops,