libceph: transition socket state prior to actual connect

Once we call ->connect(), we are racing against the actual
connection, and a subsequent transition from CONNECTING ->
CONNECTED.  Set the state to CONNECTING before that, under the
protection of the mutex, to avoid the race.

This was introduced in 928443cd,
with the original socket state code.
Signed-off-by: NSage Weil <sage@inktank.com>
Reviewed-by: NAlex Elder <elder@inktank.com>

net/ceph/messenger.c

@@ -321,6 +321,7 @@ static int ceph_tcp_connect(struct ceph_connection *con)
 
 	dout("connect %s\n", ceph_pr_addr(&con->peer_addr.in_addr));
 
+	con_sock_state_connecting(con);
 	ret = sock->ops->connect(sock, (struct sockaddr *)paddr, sizeof(*paddr),
 				 O_NONBLOCK);
 	if (ret == -EINPROGRESS) {
@@ -336,8 +337,6 @@ static int ceph_tcp_connect(struct ceph_connection *con)
 		return ret;
 	}
 	con->sock = sock;
-	con_sock_state_connecting(con);
-
 	return 0;
 }