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DLM: Save and restore socket callbacks properly

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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>
This commit is contained in:
Bob Peterson 2016-02-05 14:39:02 -05:00 committed by David Teigland
parent 1a31833d08
commit b81171cb68
1 changed files with 59 additions and 11 deletions
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70
fs/dlm/lowcomms.c
View file

@ -124,7 +124,10 @@ struct connection {
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 @@ int dlm_lowcomms_connect_node(int nodeid)
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 @@ static void lowcomms_error_report(struct sock *sk)
"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 @@ static void lowcomms_error_report(struct sock *sk)
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 @@ static void close_connection(struct connection *con, bool and_other,
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 @@ static struct socket *tcp_create_listen_sock(struct connection *con,
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 @@ static int sctp_listen_for_all(void)
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 @@ static int sctp_listen_for_all(void)
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;