nfs41: Use BIND_CONN_TO_SESSION for CB_PATH_DOWN*

The state manager can handle SEQ4_STATUS_CB_PATH_DOWN* flags with a
BIND_CONN_TO_SESSION instead of destroying the session and creating a new one.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

2 files changed, 31 insertions, 4 deletions

diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index 2c7f1cf85b8f..5fcb1ad65e5e 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -25,6 +25,7 @@ enum nfs4_client_state {
         NFS4CLNT_LEASE_CONFIRM,
         NFS4CLNT_SERVER_SCOPE_MISMATCH,
         NFS4CLNT_PURGE_STATE,
+        NFS4CLNT_BIND_CONN_TO_SESSION,
 };
 
 enum nfs4_session_state {
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 32cce4a276e8..03fa802b5529 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1640,13 +1640,20 @@ static void nfs41_handle_recallable_state_revoked(struct nfs_client *clp)
         nfs_expire_all_delegations(clp);
 }
 
-static void nfs41_handle_cb_path_down(struct nfs_client *clp)
+static void nfs41_handle_backchannel_fault(struct nfs_client *clp)
 {
         nfs_expire_all_delegations(clp);
         if (test_and_set_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state) == 0)
                 nfs4_schedule_state_manager(clp);
 }
 
+static void nfs41_handle_cb_path_down(struct nfs_client *clp)
+{
+        if (test_and_set_bit(NFS4CLNT_BIND_CONN_TO_SESSION,
+                &clp->cl_state) == 0)
+                nfs4_schedule_state_manager(clp);
+}
+
 void nfs41_handle_sequence_flag_errors(struct nfs_client *clp, u32 flags)
 {
         if (!flags)
@@ -1664,9 +1671,10 @@ void nfs41_handle_sequence_flag_errors(struct nfs_client *clp, u32 flags)
                 nfs41_handle_state_revoked(clp);
         if (flags & SEQ4_STATUS_RECALLABLE_STATE_REVOKED)
                 nfs41_handle_recallable_state_revoked(clp);
-        if (flags & (SEQ4_STATUS_CB_PATH_DOWN |
-                            SEQ4_STATUS_BACKCHANNEL_FAULT |
-                            SEQ4_STATUS_CB_PATH_DOWN_SESSION))
+        if (flags & SEQ4_STATUS_BACKCHANNEL_FAULT)
+                nfs41_handle_backchannel_fault(clp);
+        else if (flags & (SEQ4_STATUS_CB_PATH_DOWN |
+                                SEQ4_STATUS_CB_PATH_DOWN_SESSION))
                 nfs41_handle_cb_path_down(clp);
 }
 
@@ -1691,6 +1699,7 @@ static int nfs4_reset_session(struct nfs_client *clp)
         clear_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state);
         /* create_session negotiated new slot table */
         clear_bit(NFS4CLNT_RECALL_SLOT, &clp->cl_state);
+        clear_bit(NFS4CLNT_BIND_CONN_TO_SESSION, &clp->cl_state);
 
          /* Let the state manager reestablish state */
         if (!test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state))
@@ -1727,10 +1736,19 @@ static int nfs4_recall_slot(struct nfs_client *clp)
         return 0;
 }
 
+static int nfs4_bind_conn_to_session(struct nfs_client *clp)
+{
+        return nfs4_proc_bind_conn_to_session(clp);
+}
 #else /* CONFIG_NFS_V4_1 */
 static int nfs4_reset_session(struct nfs_client *clp) { return 0; }
 static int nfs4_end_drain_session(struct nfs_client *clp) { return 0; }
 static int nfs4_recall_slot(struct nfs_client *clp) { return 0; }
+
+static int nfs4_bind_conn_to_session(struct nfs_client *clp)
+{
+        return 0;
+}
 #endif /* CONFIG_NFS_V4_1 */
 
 /* Set NFS4CLNT_LEASE_EXPIRED for all v4.0 errors and for recoverable errors
@@ -1814,6 +1832,14 @@ static void nfs4_state_manager(struct nfs_client *clp)
                                 goto out_error;
                 }
 
+                /* Send BIND_CONN_TO_SESSION */
+                if (test_and_clear_bit(NFS4CLNT_BIND_CONN_TO_SESSION,
+                                &clp->cl_state) && nfs4_has_session(clp)) {
+                        status = nfs4_bind_conn_to_session(clp);
+                        if (status < 0)
+                                goto out_error;
+                }
+
                 /* First recover reboot state... */
                 if (test_bit(NFS4CLNT_RECLAIM_REBOOT, &clp->cl_state)) {
                         status = nfs4_do_reclaim(clp,