On Thu, Mar 03, 2016 at 07:09:14PM -0600, Mike Christie wrote: > On 03/03/2016 06:09 PM, Chris Leech wrote: > > When requests are being failed it's important to abort the TCP > > connection rather than let TCP wait and attempt a graceful shutdown. > > > > That can be accomplished by setting the SO_LINGER socket option with a > > linger time of 0 to drop queued data and close the connection with a RST > > instead of a FIN. > > > > Signed-off-by: Chris Leech <[email protected]> > > --- > > usr/io.c | 15 +++++++++++++++ > > 1 file changed, 15 insertions(+) > > > > diff --git a/usr/io.c b/usr/io.c > > index f552e1e..48b233c 100644 > > --- a/usr/io.c > > +++ b/usr/io.c > > @@ -391,9 +391,24 @@ iscsi_io_tcp_poll(iscsi_conn_t *conn, int timeout_ms) > > void > > iscsi_io_tcp_disconnect(iscsi_conn_t *conn) > > { > > + struct linger so_linger = { .l_onoff = 1, .l_linger = 0 }; > > + > > if (conn->socket_fd >= 0) { > > log_debug(1, "disconnecting conn %p, fd %d", conn, > > conn->socket_fd); > > + > > + /* If the state is not IN_LOGOUT, this isn't a clean shutdown > > + * and there's some sort of error handling going on. In that > > + * case, set a 0 SO_LINGER to force an abortive close (RST) and > > + * free whatever is sitting in the TCP transmit queue. This is > > + * done to prevent stale data from being sent should the > > + * network connection be restored before TCP times out. > > + */ > > + if (conn->state != ISCSI_CONN_STATE_IN_LOGOUT) { > > + setsockopt(conn->socket_fd, SOL_SOCKET, SO_LINGER, > > + &so_linger, sizeof(so_linger)); > > + } > > + > > close(conn->socket_fd); > > conn->socket_fd = -1; > > } > > > > Nice. > > For maybe a slightly different problem, but hoping I get lucky and your > patch fixes it too, I thought the network layer was still accessing > pages that we tried to send and was causing a oops. I get the part where > with your patch the network layer will not try to send data anymore, but > I guess I am asking if the network layer could still be doing some sort > of delayed cleanup process after close() has returned?
>From what I can tell in the tcp code, the zero linger handling purges all of the socket queues freeing everything before close returns. - Chris -- You received this message because you are subscribed to the Google Groups "open-iscsi" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/open-iscsi. For more options, visit https://groups.google.com/d/optout.
