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authorIlya Dryomov <idryomov@gmail.com>2016-01-20 17:50:31 +0100
committerIlya Dryomov <idryomov@gmail.com>2016-03-25 18:51:38 +0100
commit0e04dc26cc594d31ee6b1382b452b6bc83b57937 (patch)
treebc0ee4c6236224b44f9e388672e2e0a1cbfe8253
parent82dcabad750a36a2b749889bc89c5a3188775b2e (diff)
downloadlinux-0e04dc26cc594d31ee6b1382b452b6bc83b57937.tar.bz2
libceph: pick a different monitor when reconnecting
Don't try to reconnect to the same monitor when we fail to establish a session within a timeout or it's lost. For that, pick_new_mon() needs to see the old value of cur_mon, so don't clear it in __close_session() - all calls to __close_session() but one are followed by __open_session() anyway. __open_session() is only called when a new session needs to be established, so the "already open?" branch, which is now in the way, is simply dropped. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
-rw-r--r--net/ceph/mon_client.c85
1 files changed, 57 insertions, 28 deletions
diff --git a/net/ceph/mon_client.c b/net/ceph/mon_client.c
index 89029916315c..accfded53bae 100644
--- a/net/ceph/mon_client.c
+++ b/net/ceph/mon_client.c
@@ -122,45 +122,74 @@ static void __close_session(struct ceph_mon_client *monc)
ceph_msg_revoke(monc->m_subscribe);
ceph_msg_revoke_incoming(monc->m_subscribe_ack);
ceph_con_close(&monc->con);
- monc->cur_mon = -1;
+
monc->pending_auth = 0;
ceph_auth_reset(monc->auth);
}
/*
- * Open a session with a (new) monitor.
+ * Pick a new monitor at random and set cur_mon. If we are repicking
+ * (i.e. cur_mon is already set), be sure to pick a different one.
*/
-static int __open_session(struct ceph_mon_client *monc)
+static void pick_new_mon(struct ceph_mon_client *monc)
{
- char r;
- int ret;
+ int old_mon = monc->cur_mon;
- if (monc->cur_mon < 0) {
- get_random_bytes(&r, 1);
- monc->cur_mon = r % monc->monmap->num_mon;
- dout("open_session num=%d r=%d -> mon%d\n",
- monc->monmap->num_mon, r, monc->cur_mon);
- monc->sub_renew_after = jiffies; /* i.e., expired */
- monc->sub_renew_sent = 0;
+ BUG_ON(monc->monmap->num_mon < 1);
- dout("open_session mon%d opening\n", monc->cur_mon);
- ceph_con_open(&monc->con,
- CEPH_ENTITY_TYPE_MON, monc->cur_mon,
- &monc->monmap->mon_inst[monc->cur_mon].addr);
+ if (monc->monmap->num_mon == 1) {
+ monc->cur_mon = 0;
+ } else {
+ int max = monc->monmap->num_mon;
+ int o = -1;
+ int n;
+
+ if (monc->cur_mon >= 0) {
+ if (monc->cur_mon < monc->monmap->num_mon)
+ o = monc->cur_mon;
+ if (o >= 0)
+ max--;
+ }
- /* send an initial keepalive to ensure our timestamp is
- * valid by the time we are in an OPENED state */
- ceph_con_keepalive(&monc->con);
+ n = prandom_u32() % max;
+ if (o >= 0 && n >= o)
+ n++;
- /* initiatiate authentication handshake */
- ret = ceph_auth_build_hello(monc->auth,
- monc->m_auth->front.iov_base,
- monc->m_auth->front_alloc_len);
- __send_prepared_auth_request(monc, ret);
- } else {
- dout("open_session mon%d already open\n", monc->cur_mon);
+ monc->cur_mon = n;
}
- return 0;
+
+ dout("%s mon%d -> mon%d out of %d mons\n", __func__, old_mon,
+ monc->cur_mon, monc->monmap->num_mon);
+}
+
+/*
+ * Open a session with a new monitor.
+ */
+static void __open_session(struct ceph_mon_client *monc)
+{
+ int ret;
+
+ pick_new_mon(monc);
+
+ monc->sub_renew_after = jiffies; /* i.e., expired */
+ monc->sub_renew_sent = 0;
+
+ dout("%s opening mon%d\n", __func__, monc->cur_mon);
+ ceph_con_open(&monc->con, CEPH_ENTITY_TYPE_MON, monc->cur_mon,
+ &monc->monmap->mon_inst[monc->cur_mon].addr);
+
+ /*
+ * send an initial keepalive to ensure our timestamp is valid
+ * by the time we are in an OPENED state
+ */
+ ceph_con_keepalive(&monc->con);
+
+ /* initiate authentication handshake */
+ ret = ceph_auth_build_hello(monc->auth,
+ monc->m_auth->front.iov_base,
+ monc->m_auth->front_alloc_len);
+ BUG_ON(ret <= 0);
+ __send_prepared_auth_request(monc, ret);
}
static bool __sub_expired(struct ceph_mon_client *monc)
@@ -907,7 +936,7 @@ void ceph_monc_stop(struct ceph_mon_client *monc)
mutex_lock(&monc->mutex);
__close_session(monc);
-
+ monc->cur_mon = -1;
mutex_unlock(&monc->mutex);
/*