dlm: don't save callbacks after accept

When DLM calls accept() on a socket, the comm code copies the sk
after we've saved its callbacks. Afterward, it calls add_sock which
saves the callbacks a second time. Since the error reporting function
lowcomms_error_report calls the previous callback too, this results
in a recursive call to itself. This patch adds a new parameter to
function add_sock to tell whether to save the callbacks. Function
tcp_accept_from_sock (and its sctp counterpart) then calls it with
false to avoid the recursion.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

1 files changed, 12 insertions, 9 deletions

diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index 609998de533e..485494e5a28e 100644
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -541,7 +541,7 @@ static void restore_callbacks(struct connection *con, struct sock *sk)
 }
 
 /* Make a socket active */
-static void add_sock(struct socket *sock, struct connection *con)
+static void add_sock(struct socket *sock, struct connection *con, bool save_cb)
 {
         struct sock *sk = sock->sk;
 
@@ -549,7 +549,7 @@ static void add_sock(struct socket *sock, struct connection *con)
         con->sock = sock;
 
         sk->sk_user_data = con;
-        if (!test_bit(CF_IS_OTHERCON, &con->flags))
+        if (save_cb)
                 save_callbacks(con, sk);
         /* Install a data_ready callback */
         sk->sk_data_ready = lowcomms_data_ready;
@@ -806,7 +806,7 @@ static int tcp_accept_from_sock(struct connection *con)
                         newcon->othercon = othercon;
                         othercon->sock = newsock;
                         newsock->sk->sk_user_data = othercon;
-                        add_sock(newsock, othercon);
+                        add_sock(newsock, othercon, false);
                         addcon = othercon;
                 }
                 else {
@@ -819,7 +819,10 @@ static int tcp_accept_from_sock(struct connection *con)
         else {
                 newsock->sk->sk_user_data = newcon;
                 newcon->rx_action = receive_from_sock;
-                add_sock(newsock, newcon);
+                /* accept copies the sk after we've saved the callbacks, so we
+                   don't want to save them a second time or comm errors will
+                   result in calling sk_error_report recursively. */
+                add_sock(newsock, newcon, false);
                 addcon = newcon;
         }
 
@@ -919,7 +922,7 @@ static int sctp_accept_from_sock(struct connection *con)
                         newcon->othercon = othercon;
                         othercon->sock = newsock;
                         newsock->sk->sk_user_data = othercon;
-                        add_sock(newsock, othercon);
+                        add_sock(newsock, othercon, false);
                         addcon = othercon;
                 } else {
                         printk("Extra connection from node %d attempted\n", nodeid);
@@ -930,7 +933,7 @@ static int sctp_accept_from_sock(struct connection *con)
         } else {
                 newsock->sk->sk_user_data = newcon;
                 newcon->rx_action = receive_from_sock;
-                add_sock(newsock, newcon);
+                add_sock(newsock, newcon, false);
                 addcon = newcon;
         }
 
@@ -1058,7 +1061,7 @@ static void sctp_connect_to_sock(struct connection *con)
         sock->sk->sk_user_data = con;
         con->rx_action = receive_from_sock;
         con->connect_action = sctp_connect_to_sock;
-        add_sock(sock, con);
+        add_sock(sock, con, true);
 
         /* Bind to all addresses. */
         if (sctp_bind_addrs(con, 0))
@@ -1146,7 +1149,7 @@ static void tcp_connect_to_sock(struct connection *con)
         sock->sk->sk_user_data = con;
         con->rx_action = receive_from_sock;
         con->connect_action = tcp_connect_to_sock;
-        add_sock(sock, con);
+        add_sock(sock, con, true);
 
         /* Bind to our cluster-known address connecting to avoid
            routing problems */
@@ -1366,7 +1369,7 @@ static int tcp_listen_for_all(void)
 
         sock = tcp_create_listen_sock(con, dlm_local_addr[0]);
         if (sock) {
-                add_sock(sock, con);
+                add_sock(sock, con, true);
                 result = 0;
         }
         else {