DLM: Save and restore socket callbacks properly
This patch fixes the problems with patch b3a5bbfd7.
1. It removes a return statement from lowcomms_error_report
because it needs to call the original error report in all paths
through the function.
2. All socket callbacks are saved and restored, not just the
sk_error_report, and that's done so with proper locking like
sunrpc does.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index dc9ae6d..00640e7 100644
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -124,7 +124,10 @@
struct connection *othercon;
struct work_struct rwork; /* Receive workqueue */
struct work_struct swork; /* Send workqueue */
- void (*orig_error_report)(struct sock *sk);
+ void (*orig_error_report)(struct sock *);
+ void (*orig_data_ready)(struct sock *);
+ void (*orig_state_change)(struct sock *);
+ void (*orig_write_space)(struct sock *);
};
#define sock2con(x) ((struct connection *)(x)->sk_user_data)
@@ -467,10 +470,17 @@
static void lowcomms_error_report(struct sock *sk)
{
- struct connection *con = sock2con(sk);
+ struct connection *con;
struct sockaddr_storage saddr;
int buflen;
+ void (*orig_report)(struct sock *) = NULL;
+ read_lock_bh(&sk->sk_callback_lock);
+ con = sock2con(sk);
+ if (con == NULL)
+ goto out;
+
+ orig_report = con->orig_error_report;
if (con->sock == NULL ||
kernel_getpeername(con->sock, (struct sockaddr *)&saddr, &buflen)) {
printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
@@ -478,7 +488,6 @@
"sk_err=%d/%d\n", dlm_our_nodeid(),
con->nodeid, dlm_config.ci_tcp_port,
sk->sk_err, sk->sk_err_soft);
- return;
} else if (saddr.ss_family == AF_INET) {
struct sockaddr_in *sin4 = (struct sockaddr_in *)&saddr;
@@ -501,22 +510,54 @@
dlm_config.ci_tcp_port, sk->sk_err,
sk->sk_err_soft);
}
- con->orig_error_report(sk);
+out:
+ read_unlock_bh(&sk->sk_callback_lock);
+ if (orig_report)
+ orig_report(sk);
+}
+
+/* Note: sk_callback_lock must be locked before calling this function. */
+static void save_callbacks(struct connection *con, struct sock *sk)
+{
+ lock_sock(sk);
+ con->orig_data_ready = sk->sk_data_ready;
+ con->orig_state_change = sk->sk_state_change;
+ con->orig_write_space = sk->sk_write_space;
+ con->orig_error_report = sk->sk_error_report;
+ release_sock(sk);
+}
+
+static void restore_callbacks(struct connection *con, struct sock *sk)
+{
+ write_lock_bh(&sk->sk_callback_lock);
+ lock_sock(sk);
+ sk->sk_user_data = NULL;
+ sk->sk_data_ready = con->orig_data_ready;
+ sk->sk_state_change = con->orig_state_change;
+ sk->sk_write_space = con->orig_write_space;
+ sk->sk_error_report = con->orig_error_report;
+ release_sock(sk);
+ write_unlock_bh(&sk->sk_callback_lock);
}
/* Make a socket active */
static void add_sock(struct socket *sock, struct connection *con)
{
+ struct sock *sk = sock->sk;
+
+ write_lock_bh(&sk->sk_callback_lock);
con->sock = sock;
+ sk->sk_user_data = con;
+ if (!test_bit(CF_IS_OTHERCON, &con->flags))
+ save_callbacks(con, sk);
/* Install a data_ready callback */
- con->sock->sk->sk_data_ready = lowcomms_data_ready;
- con->sock->sk->sk_write_space = lowcomms_write_space;
- con->sock->sk->sk_state_change = lowcomms_state_change;
- con->sock->sk->sk_user_data = con;
- con->sock->sk->sk_allocation = GFP_NOFS;
- con->orig_error_report = con->sock->sk->sk_error_report;
- con->sock->sk->sk_error_report = lowcomms_error_report;
+ sk->sk_data_ready = lowcomms_data_ready;
+ sk->sk_write_space = lowcomms_write_space;
+ sk->sk_state_change = lowcomms_state_change;
+ sk->sk_allocation = GFP_NOFS;
+ sk->sk_error_report = lowcomms_error_report;
+ write_unlock_bh(&sk->sk_callback_lock);
}
/* Add the port number to an IPv6 or 4 sockaddr and return the address
@@ -551,6 +592,8 @@
mutex_lock(&con->sock_mutex);
if (con->sock) {
+ if (!test_bit(CF_IS_OTHERCON, &con->flags))
+ restore_callbacks(con, con->sock->sk);
sock_release(con->sock);
con->sock = NULL;
}
@@ -1192,6 +1235,8 @@
if (result < 0) {
log_print("Failed to set SO_REUSEADDR on socket: %d", result);
}
+ sock->sk->sk_user_data = con;
+
con->rx_action = tcp_accept_from_sock;
con->connect_action = tcp_connect_to_sock;
@@ -1273,6 +1318,7 @@
if (result < 0)
log_print("Could not set SCTP NODELAY error %d\n", result);
+ write_lock_bh(&sock->sk->sk_callback_lock);
/* Init con struct */
sock->sk->sk_user_data = con;
con->sock = sock;
@@ -1280,6 +1326,8 @@
con->rx_action = sctp_accept_from_sock;
con->connect_action = sctp_connect_to_sock;
+ write_unlock_bh(&sock->sk->sk_callback_lock);
+
/* Bind to all addresses. */
if (sctp_bind_addrs(con, dlm_config.ci_tcp_port))
goto create_delsock;