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chainntnfs: handling for potential deadlocks during system shutdown

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If the lnd daemon is shut down while multiple subsystems are attempting
to register for notifications, the blocking of those chain notifier
registrations may cause the daemon shutdown to deadlock. The additions
in this commit allow the registration functions to return errors rather
than potentially deadlock when the chain notifier is shut down.
This commit is contained in:
bryanvu 2016-12-15 01:07:12 -08:00 committed by Olaoluwa Osuntokun
parent b991cd3d78
commit def39799c5
1 changed files with 26 additions and 12 deletions
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38
chainntnfs/btcdnotify/btcd.go
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@ -2,6 +2,7 @@ package btcdnotify
import (
"container/heap"
"errors"
"sync"
"sync/atomic"
"time"
@ -546,7 +547,12 @@ func (b *BtcdNotifier) RegisterSpendNtfn(outpoint *wire.OutPoint) (*chainntnfs.S
spendChan: make(chan *chainntnfs.SpendDetail, 1),
}
b.notificationRegistry <- ntfn
select {
case <-b.quit:
return nil, errors.New("chainntnfs: system interrupt while " +
"attempting to register for spend notification.")
case b.notificationRegistry <- ntfn:
}
// The following conditional checks to ensure that when a spend notification
// is registered, the output hasn't already been spent. If the output
@ -603,12 +609,16 @@ func (b *BtcdNotifier) RegisterConfirmationsNtfn(txid *wire.ShaHash,
negativeConf: make(chan int32, 1),
}
b.notificationRegistry <- ntfn
return &chainntnfs.ConfirmationEvent{
Confirmed: ntfn.finConf,
NegativeConf: ntfn.negativeConf,
}, nil
select {
case <-b.quit:
return nil, errors.New("chainntnfs: system interrupt while " +
"attempting to register for confirmation notification.")
case b.notificationRegistry <- ntfn:
return &chainntnfs.ConfirmationEvent{
Confirmed: ntfn.finConf,
NegativeConf: ntfn.negativeConf,
}, nil
}
}
// blockEpochRegistration represents a client's intent to receive a
@ -625,9 +635,13 @@ func (b *BtcdNotifier) RegisterBlockEpochNtfn() (*chainntnfs.BlockEpochEvent, er
epochChan: make(chan *chainntnfs.BlockEpoch, 20),
}
b.notificationRegistry <- registration
return &chainntnfs.BlockEpochEvent{
Epochs: registration.epochChan,
}, nil
select {
case <-b.quit:
return nil, errors.New("chainntnfs: system interrupt while " +
"attempting to register for block epoch notification.")
case b.notificationRegistry <- registration:
return &chainntnfs.BlockEpochEvent{
Epochs: registration.epochChan,
}, nil
}
}