Tariq Saeed
2014-Apr-08 22:36 UTC
[Ocfs2-devel] [PATCH 1/1] ocfs2/o2net: incorrect to terminate accepting connections loop upon rejecting an ivalid one Orabug: 17489469
When o2net-accept-one() rejects an illegal connection,
it terminates the loop picking up the remaining queued connections.
This fix will continue accepting connections till the queue is
emtpy.
Signed-off-by: Tariq Saseed <tariq.x.saeed at oracle.com>
Signed-off-by: Srinivas Eeda <srinivas.eeda at oracle.com>
---
fs/ocfs2/cluster/tcp.c | 31 +++++++++++++++++++++++++++++--
1 files changed, 29 insertions(+), 2 deletions(-)
diff --git a/fs/ocfs2/cluster/tcp.c b/fs/ocfs2/cluster/tcp.c
index 2cd2406..649a651 100644
--- a/fs/ocfs2/cluster/tcp.c
+++ b/fs/ocfs2/cluster/tcp.c
@@ -1826,7 +1826,7 @@ int o2net_register_hb_callbacks(void)
/* ------------------------------------------------------------ */
-static int o2net_accept_one(struct socket *sock)
+static int o2net_accept_one(struct socket *sock, int *more)
{
int ret, slen;
struct sockaddr_in sin;
@@ -1837,6 +1837,7 @@ static int o2net_accept_one(struct socket *sock)
struct o2net_node *nn;
BUG_ON(sock == NULL);
+ *more = 0;
ret = sock_create_lite(sock->sk->sk_family, sock->sk->sk_type,
sock->sk->sk_protocol, &new_sock);
if (ret)
@@ -1848,6 +1849,7 @@ static int o2net_accept_one(struct socket *sock)
if (ret < 0)
goto out;
+ *more = 1;
new_sock->sk->sk_allocation = GFP_ATOMIC;
ret = o2net_set_nodelay(new_sock);
@@ -1946,11 +1948,36 @@ out:
return ret;
}
+/*
+ * This function is invoked in response to one or more
+ * pending accepts at softIRQ level. We must drain the
+ * entire que before returning.
+ */
+
static void o2net_accept_many(struct work_struct *work)
{
struct socket *sock = o2net_listen_sock;
- while (o2net_accept_one(sock) == 0)
+ int more;
+ int err;
+
+ /*
+ * It is critical to note that due to interrupt moderation
+ * at the network driver level, we can't assume to get a
+ * softIRQ for every single conn since tcp SYN packets
+ * can arrive back-to-back, and therefore many pending
+ * accepts may result in just 1 softIRQ. If we terminate
+ * the o2net_accept_one() loop upon seeing an err, what happens
+ * to the rest of the conns in the queue? If no new SYN
+ * arrives for hours, no softIRQ will be delivered,
+ * and the connections will just sit in the queue.
+ */
+
+ for (;;) {
+ err = o2net_accept_one(sock, &more);
+ if (!more)
+ break;
cond_resched();
+ }
}
static void o2net_listen_data_ready(struct sock *sk, int bytes)
--
1.7.1