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libceph: pick a different monitor when reconnecting

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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>
This commit is contained in:
Ilya Dryomov 2016-01-20 17:50:31 +01:00
parent 82dcabad75
commit 0e04dc26cc
1 changed files with 57 additions and 28 deletions
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85
net/ceph/mon_client.c
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@ -122,45 +122,74 @@ static void __close_session(struct ceph_mon_client *monc)
ceph_msg_revoke(monc->m_subscribe); ceph_msg_revoke(monc->m_subscribe);
ceph_msg_revoke_incoming(monc->m_subscribe_ack); ceph_msg_revoke_incoming(monc->m_subscribe_ack);
ceph_con_close(&monc->con); ceph_con_close(&monc->con);
monc->cur_mon = -1;
monc->pending_auth = 0; monc->pending_auth = 0;
ceph_auth_reset(monc->auth); 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)
{
int old_mon = monc->cur_mon;
BUG_ON(monc->monmap->num_mon < 1);
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--;
}
n = prandom_u32() % max;
if (o >= 0 && n >= o)
n++;
monc->cur_mon = n;
}
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)
{ {
char r;
int ret; int ret;
if (monc->cur_mon < 0) { pick_new_mon(monc);
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;
dout("open_session mon%d opening\n", monc->cur_mon); monc->sub_renew_after = jiffies; /* i.e., expired */
ceph_con_open(&monc->con, monc->sub_renew_sent = 0;
CEPH_ENTITY_TYPE_MON, monc->cur_mon,
&monc->monmap->mon_inst[monc->cur_mon].addr);
/* send an initial keepalive to ensure our timestamp is dout("%s opening mon%d\n", __func__, monc->cur_mon);
* valid by the time we are in an OPENED state */ ceph_con_open(&monc->con, CEPH_ENTITY_TYPE_MON, monc->cur_mon,
ceph_con_keepalive(&monc->con); &monc->monmap->mon_inst[monc->cur_mon].addr);
/* initiatiate authentication handshake */ /*
ret = ceph_auth_build_hello(monc->auth, * send an initial keepalive to ensure our timestamp is valid
monc->m_auth->front.iov_base, * by the time we are in an OPENED state
monc->m_auth->front_alloc_len); */
__send_prepared_auth_request(monc, ret); ceph_con_keepalive(&monc->con);
} else {
dout("open_session mon%d already open\n", monc->cur_mon); /* initiate authentication handshake */
} ret = ceph_auth_build_hello(monc->auth,
return 0; 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) 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); mutex_lock(&monc->mutex);
__close_session(monc); __close_session(monc);
monc->cur_mon = -1;
mutex_unlock(&monc->mutex); mutex_unlock(&monc->mutex);
/* /*