[PATCH AUTOSEL 5.13 16/59] fs: dlm: reconnect if socket error report occurs

From: Sasha Levin
Date: Mon Jul 05 2021 - 11:28:54 EST


From: Alexander Aring <aahringo@xxxxxxxxxx>

[ Upstream commit ba868d9deaab2bb1c09e50650127823925154802 ]

This patch will change the reconnect handling that if an error occurs
if a socket error callback is occurred. This will also handle reconnects
in a non blocking connecting case which is currently missing. If error
ECONNREFUSED is reported we delay the reconnect by one second.

Signed-off-by: Alexander Aring <aahringo@xxxxxxxxxx>
Signed-off-by: David Teigland <teigland@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/dlm/lowcomms.c | 60 ++++++++++++++++++++++++++++++-----------------
1 file changed, 39 insertions(+), 21 deletions(-)

diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index 47bf99373f3e..cdc50e9a5ab0 100644
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -79,6 +79,8 @@ struct connection {
#define CF_CLOSING 8
#define CF_SHUTDOWN 9
#define CF_CONNECTED 10
+#define CF_RECONNECT 11
+#define CF_DELAY_CONNECT 12
struct list_head writequeue; /* List of outgoing writequeue_entries */
spinlock_t writequeue_lock;
void (*connect_action) (struct connection *); /* What to do to connect */
@@ -87,6 +89,7 @@ struct connection {
#define MAX_CONNECT_RETRIES 3
struct hlist_node list;
struct connection *othercon;
+ struct connection *sendcon;
struct work_struct rwork; /* Receive workqueue */
struct work_struct swork; /* Send workqueue */
wait_queue_head_t shutdown_wait; /* wait for graceful shutdown */
@@ -585,6 +588,22 @@ static void lowcomms_error_report(struct sock *sk)
dlm_config.ci_tcp_port, sk->sk_err,
sk->sk_err_soft);
}
+
+ /* below sendcon only handling */
+ if (test_bit(CF_IS_OTHERCON, &con->flags))
+ con = con->sendcon;
+
+ switch (sk->sk_err) {
+ case ECONNREFUSED:
+ set_bit(CF_DELAY_CONNECT, &con->flags);
+ break;
+ default:
+ break;
+ }
+
+ if (!test_and_set_bit(CF_RECONNECT, &con->flags))
+ queue_work(send_workqueue, &con->swork);
+
out:
read_unlock_bh(&sk->sk_callback_lock);
if (orig_report)
@@ -702,6 +721,8 @@ static void close_connection(struct connection *con, bool and_other,
con->rx_leftover = 0;
con->retries = 0;
clear_bit(CF_CONNECTED, &con->flags);
+ clear_bit(CF_DELAY_CONNECT, &con->flags);
+ clear_bit(CF_RECONNECT, &con->flags);
mutex_unlock(&con->sock_mutex);
clear_bit(CF_CLOSING, &con->flags);
}
@@ -840,18 +861,15 @@ static int receive_from_sock(struct connection *con)

out_close:
mutex_unlock(&con->sock_mutex);
- if (ret != -EAGAIN) {
- /* Reconnect when there is something to send */
+ if (ret == 0) {
close_connection(con, false, true, false);
- if (ret == 0) {
- log_print("connection %p got EOF from %d",
- con, con->nodeid);
- /* handling for tcp shutdown */
- clear_bit(CF_SHUTDOWN, &con->flags);
- wake_up(&con->shutdown_wait);
- /* signal to breaking receive worker */
- ret = -1;
- }
+ log_print("connection %p got EOF from %d",
+ con, con->nodeid);
+ /* handling for tcp shutdown */
+ clear_bit(CF_SHUTDOWN, &con->flags);
+ wake_up(&con->shutdown_wait);
+ /* signal to breaking receive worker */
+ ret = -1;
}
return ret;
}
@@ -939,6 +957,7 @@ static int accept_from_sock(struct listen_connection *con)

lockdep_set_subclass(&othercon->sock_mutex, 1);
newcon->othercon = othercon;
+ othercon->sendcon = newcon;
} else {
/* close other sock con if we have something new */
close_connection(othercon, false, true, false);
@@ -1503,7 +1522,7 @@ static void send_to_sock(struct connection *con)
cond_resched();
goto out;
} else if (ret < 0)
- goto send_error;
+ goto out;
}

/* Don't starve people filling buffers */
@@ -1520,14 +1539,6 @@ static void send_to_sock(struct connection *con)
mutex_unlock(&con->sock_mutex);
return;

-send_error:
- mutex_unlock(&con->sock_mutex);
- close_connection(con, false, false, true);
- /* Requeue the send work. When the work daemon runs again, it will try
- a new connection, then call this function again. */
- queue_work(send_workqueue, &con->swork);
- return;
-
out_connect:
mutex_unlock(&con->sock_mutex);
queue_work(send_workqueue, &con->swork);
@@ -1602,8 +1613,15 @@ static void process_send_sockets(struct work_struct *work)
struct connection *con = container_of(work, struct connection, swork);

clear_bit(CF_WRITE_PENDING, &con->flags);
- if (con->sock == NULL) /* not mutex protected so check it inside too */
+
+ if (test_and_clear_bit(CF_RECONNECT, &con->flags))
+ close_connection(con, false, false, true);
+
+ if (con->sock == NULL) { /* not mutex protected so check it inside too */
+ if (test_and_clear_bit(CF_DELAY_CONNECT, &con->flags))
+ msleep(1000);
con->connect_action(con);
+ }
if (!list_empty(&con->writequeue))
send_to_sock(con);
}
--
2.30.2