SUNRPC: Don't disconnect more than once if retransmitting NFSv4 requests

NFSv4 requires us to ensure that we break the TCP connection before we're
allowed to retransmit a request. However in the case where we're
retransmitting several requests that have been sent on the same
connection, we need to ensure that we don't interfere with the attempt to
reconnect and/or break the connection again once it has been established.

We therefore introduce a 'connection' cookie that is bumped every time a
connection is broken. This allows requests to track if they need to force a
disconnection.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index 8a0629abb86a..4d80a118d538 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -86,6 +86,10 @@ struct rpc_rqst {
         unsigned long           rq_majortimeo;  /* major timeout alarm */
         unsigned long           rq_timeout;     /* Current timeout value */
         unsigned int            rq_retries;     /* # of retries */
+        unsigned int            rq_connect_cookie;
+                                                /* A cookie used to track the
+                                                   state of the transport
+                                                   connection */
         
         /*
          * Partial send handling
@@ -152,6 +156,9 @@ struct rpc_xprt {
         unsigned long           connect_timeout,
                                 bind_timeout,
                                 reestablish_timeout;
+        unsigned int            connect_cookie; /* A cookie that gets bumped
+                                                   every time the transport
+                                                   is reconnected */
 
         /*
          * Disconnection of idle transports
@@ -241,6 +248,7 @@ void			xprt_complete_rqst(struct rpc_task *task, int copied);
 void                    xprt_release_rqst_cong(struct rpc_task *task);
 void                    xprt_disconnect_done(struct rpc_xprt *xprt);
 void                    xprt_force_disconnect(struct rpc_xprt *xprt);
+void                    xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie);
 
 /*
  * Reserved bit positions in xprt->state