SUNRPC: Add the equivalent of the linger and linger2 timeouts to RPC sockets

This fixes a regression against FreeBSD servers as reported by Tomas
Kasparek. Apparently when using RPC over a TCP socket, the FreeBSD servers
don't ever react to the client closing the socket, and so commit
e06799f958bf7f9f8fae15f0c6f519953fb0257c (SUNRPC: Use shutdown() instead of
close() when disconnecting a TCP socket) causes the setup to hang forever
whenever the client attempts to close and then reconnect.

We break the deadlock by adding a 'linger2' style timeout to the socket,
after which, the client will abort the connection using a TCP 'RST'.

The default timeout is set to 15 seconds. A subsequent patch will put it
under user control by means of a systctl.

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

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index 2b0d960603b9..1758d9f5b5c3 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -260,6 +260,7 @@ void			xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie);
 #define XPRT_BOUND              (4)
 #define XPRT_BINDING            (5)
 #define XPRT_CLOSING            (6)
+#define XPRT_CONNECTION_ABORT   (7)
 
 static inline void xprt_set_connected(struct rpc_xprt *xprt)
 {