Disable gas burning for window post messages

build/params_2k.go

@@ -24,6 +24,7 @@ var UpgradeLiftoffHeight = abi.ChainEpoch(-5)
 const UpgradeKumquatHeight = 15
 const UpgradeCalicoHeight = 20
 const UpgradePersianHeight = 25
+const UpgradeClausHeight = 30
 
 var DrandSchedule = map[abi.ChainEpoch]DrandEnum{
 	0: DrandMainnet,

build/params_mainnet.go

@@ -41,6 +41,9 @@ const UpgradeKumquatHeight = 170000
 const UpgradeCalicoHeight = 265200
 const UpgradePersianHeight = UpgradeCalicoHeight + (builtin2.EpochsInHour * 60)
 
+// 2020-12-22T02:00:00Z
+const UpgradeClausHeight = 343200
+
 func init() {
 	policy.SetConsensusMinerMinPower(abi.NewStoragePower(10 << 40))
 

build/params_testground.go

@@ -90,6 +90,7 @@ var (
 	UpgradeKumquatHeight  abi.ChainEpoch = -6
 	UpgradeCalicoHeight   abi.ChainEpoch = -7
 	UpgradePersianHeight  abi.ChainEpoch = -8
+	UpgradeClausHeight    abi.ChainEpoch = -9
 
 	DrandSchedule = map[abi.ChainEpoch]DrandEnum{
 		0: DrandMainnet,

chain/vm/burn.go

@@ -67,7 +67,7 @@ func ComputeGasOverestimationBurn(gasUsed, gasLimit int64) (int64, int64) {
 	return gasLimit - gasUsed - gasToBurn.Int64(), gasToBurn.Int64()
 }
 
-func ComputeGasOutputs(gasUsed, gasLimit int64, baseFee, feeCap, gasPremium abi.TokenAmount) GasOutputs {
+func ComputeGasOutputs(gasUsed, gasLimit int64, baseFee, feeCap, gasPremium abi.TokenAmount, chargeNetworkFee bool) GasOutputs {
 	gasUsedBig := big.NewInt(gasUsed)
 	out := ZeroGasOutputs()
 
@@ -76,7 +76,12 @@ func ComputeGasOutputs(gasUsed, gasLimit int64, baseFee, feeCap, gasPremium abi.
 		baseFeeToPay = feeCap
 		out.MinerPenalty = big.Mul(big.Sub(baseFee, feeCap), gasUsedBig)
 	}
-	out.BaseFeeBurn = big.Mul(baseFeeToPay, gasUsedBig)
+
+	// If chargeNetworkFee is disabled, just skip computing the BaseFeeBurn. However,
+	// we charge all the other fees regardless.
+	if chargeNetworkFee {
+		out.BaseFeeBurn = big.Mul(baseFeeToPay, gasUsedBig)
+	}
 
 	minerTip := gasPremium
 	if big.Cmp(big.Add(baseFeeToPay, minerTip), feeCap) > 0 {

chain/vm/burn_test.go

@@ -63,7 +63,7 @@ func TestGasOutputs(t *testing.T) {
 	for _, test := range tests {
 		test := test
 		t.Run(fmt.Sprintf("%v", test), func(t *testing.T) {
-			output := ComputeGasOutputs(test.used, test.limit, baseFee, types.NewInt(test.feeCap), types.NewInt(test.premium))
+			output := ComputeGasOutputs(test.used, test.limit, baseFee, types.NewInt(test.feeCap), types.NewInt(test.premium), true)
 			i2s := func(i uint64) string {
 				return fmt.Sprintf("%d", i)
 			}

chain/vm/vm.go

@@ -32,6 +32,7 @@ import (
 	"github.com/filecoin-project/lotus/chain/actors/adt"
 	"github.com/filecoin-project/lotus/chain/actors/aerrors"
 	"github.com/filecoin-project/lotus/chain/actors/builtin/account"
+	"github.com/filecoin-project/lotus/chain/actors/builtin/miner"
 	"github.com/filecoin-project/lotus/chain/actors/builtin/reward"
 	"github.com/filecoin-project/lotus/chain/state"
 	"github.com/filecoin-project/lotus/chain/types"
@@ -561,7 +562,13 @@ func (vm *VM) ApplyMessage(ctx context.Context, cmsg types.ChainMsg) (*ApplyRet,
 	if gasUsed < 0 {
 		gasUsed = 0
 	}
-	gasOutputs := ComputeGasOutputs(gasUsed, msg.GasLimit, vm.baseFee, msg.GasFeeCap, msg.GasPremium)
+
+	burn, err := vm.shouldBurn(st, msg, errcode)
+	if err != nil {
+		return nil, xerrors.Errorf("deciding whether should burn failed: %w", err)
+	}
+
+	gasOutputs := ComputeGasOutputs(gasUsed, msg.GasLimit, vm.baseFee, msg.GasFeeCap, msg.GasPremium, burn)
 
 	if err := vm.transferFromGasHolder(builtin.BurntFundsActorAddr, gasHolder,
 		gasOutputs.BaseFeeBurn); err != nil {
@@ -599,6 +606,29 @@ func (vm *VM) ApplyMessage(ctx context.Context, cmsg types.ChainMsg) (*ApplyRet,
 	}, nil
 }
 
+func (vm *VM) shouldBurn(st *state.StateTree, msg *types.Message, errcode exitcode.ExitCode) (bool, error) {
+	// Check to see if we should burn funds. We avoid burning on successful
+	// window post. This won't catch _indirect_ window post calls, but this
+	// is the best we can get for now.
+	if vm.blockHeight > build.UpgradeClausHeight && errcode == exitcode.Ok && msg.Method == miner.Methods.SubmitWindowedPoSt {
+		// Ok, we've checked the _method_, but we still need to check
+		// the target actor. It would be nice if we could just look at
+		// the trace, but I'm not sure if that's safe?
+		if toActor, err := st.GetActor(msg.To); err != nil {
+			// If the actor wasn't found, we probably deleted it or something. Move on.
+			if !xerrors.Is(err, types.ErrActorNotFound) {
+				// Otherwise, this should never fail and something is very wrong.
+				return false, xerrors.Errorf("failed to lookup target actor: %w", err)
+			}
+		} else if builtin.IsStorageMinerActor(toActor.Code) {
+			// Ok, this is a storage miner and we've processed a window post. Remove the burn.
+			return false, nil
+		}
+	}
+
+	return true, nil
+}
+
 func (vm *VM) ActorBalance(addr address.Address) (types.BigInt, aerrors.ActorError) {
 	act, err := vm.cstate.GetActor(addr)
 	if err != nil {