From da0a78161d2b2da4819a1f05a38bb1dcbe02d951 Mon Sep 17 00:00:00 2001 From: Philipp Reisner Date: Thu, 23 Dec 2010 14:24:33 +0100 Subject: [PATCH] drbd: Be more careful with SyncSource -> Ahead transitions We may not get from SyncSource to Ahead if we have sent some P_RS_DATA_REPLY packets to the peer and are waiting for P_WRITE_ACK. Again, this is not relevant for proper tuned systems, but makes sure that the not-tuned system does not get diverging bitmaps. Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg --- drivers/block/drbd/drbd_receiver.c | 3 ++- drivers/block/drbd/drbd_req.c | 8 +++++++- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c index bf865bd83414..fd0957f9c230 100644 --- a/drivers/block/drbd/drbd_receiver.c +++ b/drivers/block/drbd/drbd_receiver.c @@ -4385,10 +4385,11 @@ static int got_BarrierAck(struct drbd_conf *mdev, struct p_header80 *h) if (mdev->state.conn == C_AHEAD && atomic_read(&mdev->ap_in_flight) == 0 && + atomic_read(&mdev->rs_pending_cnt) == 0 && list_empty(&mdev->start_resync_work.list)) { struct drbd_work *w = &mdev->start_resync_work; w->cb = w_start_resync; - drbd_queue_work_front(&mdev->data.work, w); + drbd_queue_work(&mdev->data.work, w); } return true; diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c index 889175110c91..a3f6b04ebaba 100644 --- a/drivers/block/drbd/drbd_req.c +++ b/drivers/block/drbd/drbd_req.c @@ -1002,7 +1002,13 @@ allocate_barrier: congested = 1; } - if (congested) { + if (congested && atomic_read(&mdev->rs_pending_cnt) == 0) { + /* rs_pending_cnt must be zero, otherwise the two peers + might get different bitmaps. With sane configurations + the resync stalls long before we might want to go into + AHEAD mode. + We could force the resync into PAUSE mode here if + rs_pending_cnt is > 0 ... */ queue_barrier(mdev); if (mdev->net_conf->on_congestion == OC_PULL_AHEAD) -- 2.39.5