From 20004e24356ff62b8e8141a129d2e1d50a2813b7 Mon Sep 17 00:00:00 2001 From: Lars Ellenberg Date: Tue, 14 Jun 2016 00:26:34 +0200 Subject: [PATCH] drbd: bump current uuid when resuming IO with diskless peer Scenario, starting with normal operation Connected Primary/Secondary UpToDate/UpToDate NetworkFailure Primary/Unknown UpToDate/DUnknown (frozen) ... more failures happen, secondary loses it's disk, but eventually is able to re-establish the replication link ... Connected Primary/Secondary UpToDate/Diskless (resumed; needs to bump uuid!) We used to just resume/resent suspended requests, without bumping the UUID. Which will lead to problems later, when we want to re-attach the disk on the peer, without first disconnecting, or if we experience additional failures, because we now have diverging data without being able to recognize it. Make sure we also bump the current data generation UUID, if we notice "peer disk unknown" -> "peer disk known bad". Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe --- drivers/block/drbd/drbd_state.c | 34 ++++++++++++++++++++++++++++------ 1 file changed, 28 insertions(+), 6 deletions(-) diff --git a/drivers/block/drbd/drbd_state.c b/drivers/block/drbd/drbd_state.c index 7562c5c..a1b5e6c9 100644 --- a/drivers/block/drbd/drbd_state.c +++ b/drivers/block/drbd/drbd_state.c @@ -1637,6 +1637,26 @@ static void broadcast_state_change(struct drbd_state_change *state_change) #undef REMEMBER_STATE_CHANGE } +/* takes old and new peer disk state */ +static bool lost_contact_to_peer_data(enum drbd_disk_state os, enum drbd_disk_state ns) +{ + if ((os >= D_INCONSISTENT && os != D_UNKNOWN && os != D_OUTDATED) + && (ns < D_INCONSISTENT || ns == D_UNKNOWN || ns == D_OUTDATED)) + return true; + + /* Scenario, starting with normal operation + * Connected Primary/Secondary UpToDate/UpToDate + * NetworkFailure Primary/Unknown UpToDate/DUnknown (frozen) + * ... + * Connected Primary/Secondary UpToDate/Diskless (resumed; needs to bump uuid!) + */ + if (os == D_UNKNOWN + && (ns == D_DISKLESS || ns == D_FAILED || ns == D_OUTDATED)) + return true; + + return false; +} + /** * after_state_ch() - Perform after state change actions that may sleep * @device: DRBD device. @@ -1708,6 +1728,13 @@ static void after_state_ch(struct drbd_device *device, union drbd_state os, idr_for_each_entry(&connection->peer_devices, peer_device, vnr) clear_bit(NEW_CUR_UUID, &peer_device->device->flags); rcu_read_unlock(); + + /* We should actively create a new uuid, _before_ + * we resume/resent, if the peer is diskless + * (recovery from a multiple error scenario). + * Currently, this happens with a slight delay + * below when checking lost_contact_to_peer_data() ... + */ _tl_restart(connection, RESEND); _conn_request_state(connection, (union drbd_state) { { .susp_fen = 1 } }, @@ -1751,12 +1778,7 @@ static void after_state_ch(struct drbd_device *device, union drbd_state os, BM_LOCKED_TEST_ALLOWED); /* Lost contact to peer's copy of the data */ - if ((os.pdsk >= D_INCONSISTENT && - os.pdsk != D_UNKNOWN && - os.pdsk != D_OUTDATED) - && (ns.pdsk < D_INCONSISTENT || - ns.pdsk == D_UNKNOWN || - ns.pdsk == D_OUTDATED)) { + if (lost_contact_to_peer_data(os.pdsk, ns.pdsk)) { if (get_ldev(device)) { if ((ns.role == R_PRIMARY || ns.peer == R_PRIMARY) && device->ldev->md.uuid[UI_BITMAP] == 0 && ns.disk >= D_UP_TO_DATE) { -- 2.7.4