[PATCH AUTOSEL 3.18 40/61] drbd: skip spurious timeout (ping-timeo) when failing promote

Sasha Levin
2019-01-28T16:30:16Z

From: Lars Ellenberg <lars.ellenberg@linbit.com>

[ Upstream commit 9848b6ddd8c92305252f94592c5e278574e7a6ac ]

If you try to promote a Secondary while connected to a Primary
and allow-two-primaries is NOT set, we will wait for "ping-timeout"
to give this node a chance to detect a dead primary,
in case the cluster manager noticed faster than we did.

But if we then are *still* connected to a Primary,
we fail (after an additional timeout of ping-timout).

This change skips the spurious second timeout.

Most people won't notice really,
since "ping-timeout" by default is half a second.

But in some installations, ping-timeout may be 10 or 20 seconds or more,
and spuriously delaying the error return becomes annoying.

Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/block/drbd/drbd_nl.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 1cd47df44bda..591d309b005e 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -632,14 +632,15 @@ drbd_set_role(struct drbd_device *const device, enum drbd_role new_role, int for
if (rv == SS_TWO_PRIMARIES) {
/* Maybe the peer is detected as dead very soon...
retry at most once more in this case. */
- int timeo;
- rcu_read_lock();
- nc = rcu_dereference(connection->net_conf);
- timeo = nc ? (nc->ping_timeo + 1) * HZ / 10 : 1;
- rcu_read_unlock();
- schedule_timeout_interruptible(timeo);
- if (try < max_tries)
+ if (try < max_tries) {
+ int timeo;
try = max_tries - 1;
+ rcu_read_lock();
+ nc = rcu_dereference(connection->net_conf);
+ timeo = nc ? (nc->ping_timeo + 1) * HZ / 10 : 1;
+ rcu_read_unlock();
+ schedule_timeout_interruptible(timeo);
+ }
continue;
}
if (rv < SS_SUCCESS) {
--
2.19.1