Add a check for the connection being shut down to the krpc

client just before queuing a request for the connection. The
code already had a check for the connection being shut down
while the request was queued, but not one for the shut down
having been initiated by the server before the request was
in the queue. This appears to fix the problem of slow reconnects
against an NFS server that drops inactive connections reported
by Olaf Seibert, but does not fix the case
where the FreeBSD client generates RST segments at about the
same time as ACKs. This is still a problem that is being
investigated. This patch does not cause a regression for this
case.

Tested by:	Olaf Seibert, Daniel Braniss
Reviewed by:	dfr
MFC after:	5 days

1 files changed, 16 insertions, 0 deletions

diff --git a/sys/rpc/clnt_vc.c b/sys/rpc/clnt_vc.c
index 85e89ab..2e5fe41 100644
--- a/sys/rpc/clnt_vc.c
+++ b/sys/rpc/clnt_vc.c
@@ -413,6 +413,22 @@ call_again:
 
 	cr->cr_xid = xid;
 	mtx_lock(&ct->ct_lock);
+	/*
+	 * Check to see if the other end has already started to close down
+	 * the connection. The upcall will have set ct_error.re_status
+	 * to RPC_CANTRECV if this is the case.
+	 * If the other end starts to close down the connection after this
+	 * point, it will be detected later when cr_error is checked,
+	 * since the request is in the ct_pending queue.
+	 */
+	if (ct->ct_error.re_status == RPC_CANTRECV) {
+		if (errp != &ct->ct_error) {
+			errp->re_errno = ct->ct_error.re_errno;
+			errp->re_status = RPC_CANTRECV;
+		}
+		stat = RPC_CANTRECV;
+		goto out;
+	}
 	TAILQ_INSERT_TAIL(&ct->ct_pending, cr, cr_link);
 	mtx_unlock(&ct->ct_lock);