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drbd: Fix an connection drop issue after enabling allow-two-primaries

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Since drbd-8.4.0 it is possible to change the allow-two-primaries
network option while the connection is established.

The sequence code used to partially order packets from the
data socket with packets from the meta-data socket, still assued
that the allow-two-primaries option is constant while the
connection is established.

I.e.
On a node that has the RESOLVE_CONFLICTS bits set, after enabling
allow-two-primaries, when receiving the next data packet it timed out
while waiting for the necessary packets on the data socket to arrive
(wait_for_and_update_peer_seq() function).

Fixed that by always tracking the sequence number, but only waiting
for it if allow-two-primaries is set.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Philipp Reisner 2013-10-23 10:59:16 +02:00 committed by Jens Axboe
parent 69babf05cb
commit b874d231e1
1 changed files with 16 additions and 23 deletions
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39
drivers/block/drbd/drbd_receiver.c
View File

@ -1890,29 +1890,11 @@ static u32 seq_max(u32 a, u32 b)
return seq_greater(a, b) ? a : b;
}
static bool need_peer_seq(struct drbd_conf *mdev)
{
struct drbd_tconn *tconn = mdev->tconn;
int tp;
/*
* We only need to keep track of the last packet_seq number of our peer
* if we are in dual-primary mode and we have the resolve-conflicts flag set; see
* handle_write_conflicts().
*/
rcu_read_lock();
tp = rcu_dereference(mdev->tconn->net_conf)->two_primaries;
rcu_read_unlock();
return tp && test_bit(RESOLVE_CONFLICTS, &tconn->flags);
}
static void update_peer_seq(struct drbd_conf *mdev, unsigned int peer_seq)
{
unsigned int newest_peer_seq;
if (need_peer_seq(mdev)) {
if (test_bit(RESOLVE_CONFLICTS, &mdev->tconn->flags)) {
spin_lock(&mdev->peer_seq_lock);
newest_peer_seq = seq_max(mdev->peer_seq, peer_seq);
mdev->peer_seq = newest_peer_seq;
@ -1972,22 +1954,31 @@ static int wait_for_and_update_peer_seq(struct drbd_conf *mdev, const u32 peer_s
{
DEFINE_WAIT(wait);
long timeout;
int ret;
int ret = 0, tp;
if (!need_peer_seq(mdev))
if (!test_bit(RESOLVE_CONFLICTS, &mdev->tconn->flags))
return 0;
spin_lock(&mdev->peer_seq_lock);
for (;;) {
if (!seq_greater(peer_seq - 1, mdev->peer_seq)) {
mdev->peer_seq = seq_max(mdev->peer_seq, peer_seq);
ret = 0;
break;
}
if (signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
rcu_read_lock();
tp = rcu_dereference(mdev->tconn->net_conf)->two_primaries;
rcu_read_unlock();
if (!tp)
break;
/* Only need to wait if two_primaries is enabled */
prepare_to_wait(&mdev->seq_wait, &wait, TASK_INTERRUPTIBLE);
spin_unlock(&mdev->peer_seq_lock);
rcu_read_lock();
@ -2228,8 +2219,10 @@ static int receive_Data(struct drbd_tconn *tconn, struct packet_info *pi)
}
goto out_interrupted;
}
} else
} else {
update_peer_seq(mdev, peer_seq);
spin_lock_irq(&mdev->tconn->req_lock);
}
list_add(&peer_req->w.list, &mdev->active_ee);
spin_unlock_irq(&mdev->tconn->req_lock);