dlm: try other IPs when sctp init assoc fails

Currently, if we cannot create a association to the first IP addr
that is added to DLM, the SCTP init assoc code will just retry
the same IP. This patch adds a simple failover schemes where we
will try one of the addresses that was passed into DLM.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: David Teigland <teigland@redhat.com>

diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index 87e68dd0147927f8901bdad47e92d535c2ca91eb..56015c9e8d00a0c7c3dcb983183a1f3d6f9a14d2 100644 (file)
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -126,6 +126,7 @@ struct connection {
        struct connection *othercon;
        struct work_struct rwork; /* Receive workqueue */
        struct work_struct swork; /* Send workqueue */
+       bool try_new_addr;
 };
 #define sock2con(x) ((struct connection *)(x)->sk_user_data)
 
@@ -144,6 +145,7 @@ struct dlm_node_addr {
        struct list_head list;
        int nodeid;
        int addr_count;
+       int curr_addr_index;
        struct sockaddr_storage *addr[DLM_MAX_ADDR_COUNT];
 };
 
@@ -310,7 +312,7 @@ static int addr_compare(struct sockaddr_storage *x, struct sockaddr_storage *y)
 }
 
 static int nodeid_to_addr(int nodeid, struct sockaddr_storage *sas_out,
-                         struct sockaddr *sa_out)
+                         struct sockaddr *sa_out, bool try_new_addr)
 {
        struct sockaddr_storage sas;
        struct dlm_node_addr *na;
@@ -320,8 +322,16 @@ static int nodeid_to_addr(int nodeid, struct sockaddr_storage *sas_out,
 
        spin_lock(&dlm_node_addrs_spin);
        na = find_node_addr(nodeid);
-       if (na && na->addr_count)
-               memcpy(&sas, na->addr[0], sizeof(struct sockaddr_storage));
+       if (na && na->addr_count) {
+               if (try_new_addr) {
+                       na->curr_addr_index++;
+                       if (na->curr_addr_index == na->addr_count)
+                               na->curr_addr_index = 0;
+               }
+
+               memcpy(&sas, na->addr[na->curr_addr_index ],
+                       sizeof(struct sockaddr_storage));
+       }
        spin_unlock(&dlm_node_addrs_spin);
 
        if (!na)
@@ -353,19 +363,22 @@ static int addr_to_nodeid(struct sockaddr_storage *addr, int *nodeid)
 {
        struct dlm_node_addr *na;
        int rv = -EEXIST;
+       int addr_i;
 
        spin_lock(&dlm_node_addrs_spin);
        list_for_each_entry(na, &dlm_node_addrs, list) {
                if (!na->addr_count)
                        continue;
 
-               if (!addr_compare(na->addr[0], addr))
-                       continue;
-
-               *nodeid = na->nodeid;
-               rv = 0;
-               break;
+               for (addr_i = 0; addr_i < na->addr_count; addr_i++) {
+                       if (addr_compare(na->addr[addr_i], addr)) {
+                               *nodeid = na->nodeid;
+                               rv = 0;
+                               goto unlock;
+                       }
+               }
        }
+unlock:
        spin_unlock(&dlm_node_addrs_spin);
        return rv;
 }
@@ -561,6 +574,21 @@ static void sctp_send_shutdown(sctp_assoc_t associd)
 
 static void sctp_init_failed_foreach(struct connection *con)
 {
+
+       /*
+        * Don't try to recover base con and handle race where the
+        * other node's assoc init creates a assoc and we get that
+        * notification, then we get a notification that our attempt
+        * failed due. This happens when we are still trying the primary
+        * address, but the other node has already tried secondary addrs
+        * and found one that worked.
+        */
+       if (!con->nodeid || con->sctp_assoc)
+               return;
+
+       log_print("Retrying SCTP association init for node %d\n", con->nodeid);
+
+       con->try_new_addr = true;
        con->sctp_assoc = 0;
        if (test_and_clear_bit(CF_INIT_PENDING, &con->flags)) {
                if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags))
@@ -663,6 +691,7 @@ static void process_sctp_notification(struct connection *con,
                                 nodeid, (int)sn->sn_assoc_change.sac_assoc_id);
 
                        new_con->sctp_assoc = sn->sn_assoc_change.sac_assoc_id;
+                       new_con->try_new_addr = false;
                        /* Send any pending writes */
                        clear_bit(CF_CONNECT_PENDING, &new_con->flags);
                        clear_bit(CF_INIT_PENDING, &new_con->flags);
@@ -984,7 +1013,8 @@ static void sctp_init_assoc(struct connection *con)
        if (con->retries++ > MAX_CONNECT_RETRIES)
                return;
 
-       if (nodeid_to_addr(con->nodeid, NULL, (struct sockaddr *)&rem_addr)) {
+       if (nodeid_to_addr(con->nodeid, NULL, (struct sockaddr *)&rem_addr,
+                          con->try_new_addr)) {
                log_print("no address for nodeid %d", con->nodeid);
                return;
        }
@@ -1016,6 +1046,14 @@ static void sctp_init_assoc(struct connection *con)
        iov[0].iov_base = page_address(e->page)+offset;
        iov[0].iov_len = len;
 
+       if (rem_addr.ss_family == AF_INET) {
+               struct sockaddr_in *sin = (struct sockaddr_in *)&rem_addr;
+               log_print("Trying to connect to %pI4", &sin->sin_addr.s_addr);
+       } else {
+               struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&rem_addr;
+               log_print("Trying to connect to %pI6", &sin6->sin6_addr);
+       }
+
        cmsg = CMSG_FIRSTHDR(&outmessage);
        cmsg->cmsg_level = IPPROTO_SCTP;
        cmsg->cmsg_type = SCTP_SNDRCV;
@@ -1024,6 +1062,7 @@ static void sctp_init_assoc(struct connection *con)
        memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
        sinfo->sinfo_ppid = cpu_to_le32(dlm_our_nodeid());
        outmessage.msg_controllen = cmsg->cmsg_len;
+       sinfo->sinfo_flags |= SCTP_ADDR_OVER;
 
        ret = kernel_sendmsg(base_con->sock, &outmessage, iov, 1, len);
        if (ret < 0) {
@@ -1076,7 +1115,7 @@ static void tcp_connect_to_sock(struct connection *con)
                goto out_err;
 
        memset(&saddr, 0, sizeof(saddr));
-       result = nodeid_to_addr(con->nodeid, &saddr, NULL);
+       result = nodeid_to_addr(con->nodeid, &saddr, NULL, false);
        if (result < 0) {
                log_print("no address for nodeid %d", con->nodeid);
                goto out_err;