miner_state.go

package miner

import (
	"fmt"
	"reflect"
	"sort"

	addr "github.com/filecoin-project/go-address"
	"github.com/filecoin-project/go-bitfield"
	"github.com/filecoin-project/go-state-types/abi"
	"github.com/filecoin-project/go-state-types/big"
	"github.com/filecoin-project/go-state-types/dline"
	xc "github.com/filecoin-project/go-state-types/exitcode"
	cid "github.com/ipfs/go-cid"
	xerrors "golang.org/x/xerrors"

	"github.com/filecoin-project/specs-actors/v8/actors/builtin"
	"github.com/filecoin-project/specs-actors/v8/actors/util/adt"
)

// Balance of Miner Actor should be greater than or equal to
// the sum of PreCommitDeposits and LockedFunds.
// It is possible for balance to fall below the sum of
// PCD, LF and InitialPledgeRequirements, and this is a bad
// state (IP Debt) that limits a miner actor's behavior (i.e. no balance withdrawals)
// Excess balance as computed by st.GetAvailableBalance will be
// withdrawable or usable for pre-commit deposit or pledge lock-up.
type State struct {
	// Information not related to sectors.
	Info cid.Cid

	PreCommitDeposits abi.TokenAmount // Total funds locked as PreCommitDeposits
	LockedFunds       abi.TokenAmount // Total rewards and added funds locked in vesting table

	VestingFunds cid.Cid // VestingFunds (Vesting Funds schedule for the miner).

	FeeDebt abi.TokenAmount // Absolute value of debt this miner owes from unpaid fees

	InitialPledge abi.TokenAmount // Sum of initial pledge requirements of all active sectors

	// Sectors that have been pre-committed but not yet proven.
	PreCommittedSectors cid.Cid // Map, HAMT[SectorNumber]SectorPreCommitOnChainInfo

	// PreCommittedSectorsCleanUp maintains the state required to cleanup expired PreCommittedSectors.
	PreCommittedSectorsCleanUp cid.Cid // BitFieldQueue (AMT[Epoch]*BitField)

	// Allocated sector IDs. Sector IDs can never be reused once allocated.
	AllocatedSectors cid.Cid // BitField

	// Information for all proven and not-yet-garbage-collected sectors.
	//
	// Sectors are removed from this AMT when the partition to which the
	// sector belongs is compacted.
	Sectors cid.Cid // Array, AMT[SectorNumber]SectorOnChainInfo (sparse)

	// DEPRECATED. This field will change names and no longer be updated every proving period in a future upgrade
	// The first epoch in this miner's current proving period. This is the first epoch in which a PoSt for a
	// partition at the miner's first deadline may arrive. Alternatively, it is after the last epoch at which
	// a PoSt for the previous window is valid.
	// Always greater than zero, this may be greater than the current epoch for genesis miners in the first
	// WPoStProvingPeriod epochs of the chain; the epochs before the first proving period starts are exempt from Window
	// PoSt requirements.
	// Updated at the end of every period by a cron callback.
	ProvingPeriodStart abi.ChainEpoch

	// DEPRECATED. This field will be removed from state in a future upgrade.
	// Index of the deadline within the proving period beginning at ProvingPeriodStart that has not yet been
	// finalized.
	// Updated at the end of each deadline window by a cron callback.
	CurrentDeadline uint64

	// The sector numbers due for PoSt at each deadline in the current proving period, frozen at period start.
	// New sectors are added and expired ones removed at proving period boundary.
	// Faults are not subtracted from this in state, but on the fly.
	Deadlines cid.Cid

	// Deadlines with outstanding fees for early sector termination.
	EarlyTerminations bitfield.BitField

	// True when miner cron is active, false otherwise
	DeadlineCronActive bool
}

// Bitwidth of AMTs determined empirically from mutation patterns and projections of mainnet data.
const PrecommitCleanUpAmtBitwidth = 6
const SectorsAmtBitwidth = 5

type MinerInfo struct {
	// Account that owns this miner.
	// - Income and returned collateral are paid to this address.
	// - This address is also allowed to change the worker address for the miner.
	Owner addr.Address // Must be an ID-address.

	// Worker account for this miner.
	// The associated pubkey-type address is used to sign blocks and messages on behalf of this miner.
	Worker addr.Address // Must be an ID-address.

	// Additional addresses that are permitted to submit messages controlling this actor (optional).
	ControlAddresses []addr.Address // Must all be ID addresses.

	PendingWorkerKey *WorkerKeyChange

	// Byte array representing a Libp2p identity that should be used when connecting to this miner.
	PeerId abi.PeerID

	// Slice of byte arrays representing Libp2p multi-addresses used for establishing a connection with this miner.
	Multiaddrs []abi.Multiaddrs

	// The proof type used for Window PoSt for this miner.
	// A miner may commit sectors with different seal proof types (but compatible sector size and
	// corresponding PoSt proof types).
	WindowPoStProofType abi.RegisteredPoStProof

	// Amount of space in each sector committed by this miner.
	// This is computed from the proof type and represented here redundantly.
	SectorSize abi.SectorSize

	// The number of sectors in each Window PoSt partition (proof).
	// This is computed from the proof type and represented here redundantly.
	WindowPoStPartitionSectors uint64

	// The next epoch this miner is eligible for certain permissioned actor methods
	// and winning block elections as a result of being reported for a consensus fault.
	ConsensusFaultElapsed abi.ChainEpoch

	// A proposed new owner account for this miner.
	// Must be confirmed by a message from the pending address itself.
	PendingOwnerAddress *addr.Address
}

type WorkerKeyChange struct {
	NewWorker   addr.Address // Must be an ID address
	EffectiveAt abi.ChainEpoch
}

// Information provided by a miner when pre-committing a sector.
type SectorPreCommitInfo struct {
	SealProof       abi.RegisteredSealProof
	SectorNumber    abi.SectorNumber
	SealedCID       cid.Cid `checked:"true"` // CommR
	SealRandEpoch   abi.ChainEpoch
	DealIDs         []abi.DealID
	Expiration      abi.ChainEpoch
	ReplaceCapacity bool // Whether to replace a "committed capacity" no-deal sector (requires non-empty DealIDs)
	// The committed capacity sector to replace, and it's deadline/partition location
	ReplaceSectorDeadline  uint64
	ReplaceSectorPartition uint64
	ReplaceSectorNumber    abi.SectorNumber
}

// Information stored on-chain for a pre-committed sector.
type SectorPreCommitOnChainInfo struct {
	Info               SectorPreCommitInfo
	PreCommitDeposit   abi.TokenAmount
	PreCommitEpoch     abi.ChainEpoch
	DealWeight         abi.DealWeight // Integral of active deals over sector lifetime
	VerifiedDealWeight abi.DealWeight // Integral of active verified deals over sector lifetime
}

// Information stored on-chain for a proven sector.
type SectorOnChainInfo struct {
	SectorNumber          abi.SectorNumber
	SealProof             abi.RegisteredSealProof // The seal proof type implies the PoSt proof/s
	SealedCID             cid.Cid                 // CommR
	DealIDs               []abi.DealID
	Activation            abi.ChainEpoch  // Epoch during which the sector proof was accepted
	Expiration            abi.ChainEpoch  // Epoch during which the sector expires
	DealWeight            abi.DealWeight  // Integral of active deals over sector lifetime
	VerifiedDealWeight    abi.DealWeight  // Integral of active verified deals over sector lifetime
	InitialPledge         abi.TokenAmount // Pledge collected to commit this sector
	ExpectedDayReward     abi.TokenAmount // Expected one day projection of reward for sector computed at activation time
	ExpectedStoragePledge abi.TokenAmount // Expected twenty day projection of reward for sector computed at activation time
	ReplacedSectorAge     abi.ChainEpoch  // Age of sector this sector replaced or zero
	ReplacedDayReward     abi.TokenAmount // Day reward of sector this sector replace or zero
	SectorKeyCID          *cid.Cid        // The original SealedSectorCID, only gets set on the first ReplicaUpdate
}

func ConstructState(store adt.Store, infoCid cid.Cid, periodStart abi.ChainEpoch, deadlineIndex uint64) (*State, error) {
	emptyPrecommitMapCid, err := adt.StoreEmptyMap(store, builtin.DefaultHamtBitwidth)
	if err != nil {
		return nil, xerrors.Errorf("failed to construct empty map: %w", err)
	}
	emptyPrecommitsCleanUpArrayCid, err := adt.StoreEmptyArray(store, PrecommitCleanUpAmtBitwidth)
	if err != nil {
		return nil, xerrors.Errorf("failed to construct empty precommits array: %w", err)
	}
	emptySectorsArrayCid, err := adt.StoreEmptyArray(store, SectorsAmtBitwidth)
	if err != nil {
		return nil, xerrors.Errorf("failed to construct empty sectors array: %w", err)
	}

	emptyBitfield := bitfield.NewFromSet(nil)
	emptyBitfieldCid, err := store.Put(store.Context(), emptyBitfield)
	if err != nil {
		return nil, xerrors.Errorf("failed to construct empty bitfield: %w", err)
	}
	emptyDeadline, err := ConstructDeadline(store)
	if err != nil {
		return nil, xerrors.Errorf("failed to construct empty deadline: %w", err)
	}
	emptyDeadlineCid, err := store.Put(store.Context(), emptyDeadline)
	if err != nil {
		return nil, xerrors.Errorf("failed to construct empty deadline: %w", err)
	}
	emptyDeadlines := ConstructDeadlines(emptyDeadlineCid)
	emptyDeadlinesCid, err := store.Put(store.Context(), emptyDeadlines)
	if err != nil {
		return nil, xerrors.Errorf("failed to construct empty deadlines: %w", err)
	}
	emptyVestingFundsCid, err := store.Put(store.Context(), ConstructVestingFunds())
	if err != nil {
		return nil, xerrors.Errorf("failed to construct empty vesting funds: %w", err)
	}

	return &State{
		Info: infoCid,

		PreCommitDeposits: abi.NewTokenAmount(0),
		LockedFunds:       abi.NewTokenAmount(0),
		FeeDebt:           abi.NewTokenAmount(0),

		VestingFunds: emptyVestingFundsCid,

		InitialPledge: abi.NewTokenAmount(0),

		PreCommittedSectors:        emptyPrecommitMapCid,
		PreCommittedSectorsCleanUp: emptyPrecommitsCleanUpArrayCid,
		AllocatedSectors:           emptyBitfieldCid,
		Sectors:                    emptySectorsArrayCid,
		ProvingPeriodStart:         periodStart,
		CurrentDeadline:            deadlineIndex,
		Deadlines:                  emptyDeadlinesCid,
		EarlyTerminations:          bitfield.New(),
		DeadlineCronActive:         false,
	}, nil
}

func ConstructMinerInfo(owner, worker addr.Address, controlAddrs []addr.Address, pid []byte, multiAddrs []abi.Multiaddrs,
	windowPoStProofType abi.RegisteredPoStProof) (*MinerInfo, error) {
	sectorSize, err := windowPoStProofType.SectorSize()
	if err != nil {
		return nil, xc.ErrIllegalArgument.Wrapf("invalid sector size: %w", err)
	}

	partitionSectors, err := builtin.PoStProofWindowPoStPartitionSectors(windowPoStProofType)
	if err != nil {
		return nil, xc.ErrIllegalArgument.Wrapf("invalid partition sectors: %w", err)
	}

	return &MinerInfo{
		Owner:                      owner,
		Worker:                     worker,
		ControlAddresses:           controlAddrs,
		PendingWorkerKey:           nil,
		PeerId:                     pid,
		Multiaddrs:                 multiAddrs,
		WindowPoStProofType:        windowPoStProofType,
		SectorSize:                 sectorSize,
		WindowPoStPartitionSectors: partitionSectors,
		ConsensusFaultElapsed:      abi.ChainEpoch(-1),
		PendingOwnerAddress:        nil,
	}, nil
}

func (st *State) GetInfo(store adt.Store) (*MinerInfo, error) {
	var info MinerInfo
	if err := store.Get(store.Context(), st.Info, &info); err != nil {
		return nil, xerrors.Errorf("failed to get miner info %w", err)
	}
	return &info, nil
}

func (st *State) SaveInfo(store adt.Store, info *MinerInfo) error {
	c, err := store.Put(store.Context(), info)
	if err != nil {
		return err
	}
	st.Info = c
	return nil
}

// Returns deadline calculations for the current proving period, according to the current epoch and constant state offset
func (st *State) DeadlineInfo(currEpoch abi.ChainEpoch) *dline.Info {
	return NewDeadlineInfoFromOffsetAndEpoch(st.ProvingPeriodStart, currEpoch)
}

// Returns deadline calculations for the state recorded proving period and deadline. This is out of date if the a
// miner does not have an active miner cron
func (st *State) RecordedDeadlineInfo(currEpoch abi.ChainEpoch) *dline.Info {
	return NewDeadlineInfo(st.ProvingPeriodStart, st.CurrentDeadline, currEpoch)
}

// Returns current proving period start for the current epoch according to the current epoch and constant state offset
func (st *State) CurrentProvingPeriodStart(currEpoch abi.ChainEpoch) abi.ChainEpoch {
	dlInfo := st.DeadlineInfo(currEpoch)
	return dlInfo.PeriodStart
}

// Returns deadline calculations for the current (according to state) proving period
func (st *State) QuantSpecForDeadline(dlIdx uint64) builtin.QuantSpec {
	return QuantSpecForDeadline(NewDeadlineInfo(st.ProvingPeriodStart, dlIdx, 0))
}

type CollisionPolicy bool

const (
	DenyCollisions  = CollisionPolicy(false)
	AllowCollisions = CollisionPolicy(true)
)

// Marks a set of sector numbers as having been allocated.
// If policy is `DenyCollisions`, fails if the set intersects with the sector numbers already allocated.
func (st *State) AllocateSectorNumbers(store adt.Store, sectorNos bitfield.BitField, policy CollisionPolicy) error {
	var priorAllocation bitfield.BitField
	if err := store.Get(store.Context(), st.AllocatedSectors, &priorAllocation); err != nil {
		return xc.ErrIllegalState.Wrapf("failed to load allocated sectors bitfield: %w", err)
	}

	if policy != AllowCollisions {
		// NOTE: A fancy merge algorithm could extract this intersection while merging, below, saving
		// one iteration of the runs.
		collisions, err := bitfield.IntersectBitField(priorAllocation, sectorNos)
		if err != nil {
			return xerrors.Errorf("failed to intersect sector numbers: %w", err)
		}
		if empty, err := collisions.IsEmpty(); err != nil {
			return xerrors.Errorf("failed to check if intersection is empty: %w", err)
		} else if !empty {
			return xc.ErrIllegalArgument.Wrapf("sector numbers %v already allocated", collisions)
		}
	}

	newAllocation, err := bitfield.MergeBitFields(priorAllocation, sectorNos)
	if err != nil {
		return xc.ErrIllegalState.Wrapf("failed to merge allocated bitfield with mask: %w", err)
	}

	if root, err := store.Put(store.Context(), newAllocation); err != nil {
		return xc.ErrIllegalArgument.Wrapf("failed to store allocated sectors bitfield after adding %v: %w", sectorNos, err)
	} else {
		st.AllocatedSectors = root
	}
	return nil
}

// Stores a pre-committed sector info, failing if the sector number is already present.
func (st *State) PutPrecommittedSectors(store adt.Store, precommits ...*SectorPreCommitOnChainInfo) error {
	precommitted, err := adt.AsMap(store, st.PreCommittedSectors, builtin.DefaultHamtBitwidth)
	if err != nil {
		return err
	}

	for _, precommit := range precommits {
		// NOTE: HAMT batch operations could reduce total state read/write cost of this batch.
		if modified, err := precommitted.PutIfAbsent(SectorKey(precommit.Info.SectorNumber), precommit); err != nil {
			return xerrors.Errorf("failed to store pre-commitment for %v: %w", precommit, err)
		} else if !modified {
			return xerrors.Errorf("sector %v already pre-committed", precommit.Info.SectorNumber)
		}
	}
	st.PreCommittedSectors, err = precommitted.Root()
	return err
}

func (st *State) GetPrecommittedSector(store adt.Store, sectorNo abi.SectorNumber) (*SectorPreCommitOnChainInfo, bool, error) {
	precommitted, err := adt.AsMap(store, st.PreCommittedSectors, builtin.DefaultHamtBitwidth)
	if err != nil {
		return nil, false, err
	}

	var info SectorPreCommitOnChainInfo
	found, err := precommitted.Get(SectorKey(sectorNo), &info)
	if err != nil {
		return nil, false, xerrors.Errorf("failed to load precommitment for %v: %w", sectorNo, err)
	}
	return &info, found, nil
}

// Load all precommits or fail trying
func (st *State) GetAllPrecommittedSectors(store adt.Store, sectorNos bitfield.BitField) ([]*SectorPreCommitOnChainInfo, error) {
	precommits := make([]*SectorPreCommitOnChainInfo, 0)
	precommitted, err := adt.AsMap(store, st.PreCommittedSectors, builtin.DefaultHamtBitwidth)
	if err != nil {
		return nil, err
	}

	if err := sectorNos.ForEach(func(sectorNo uint64) error {
		if sectorNo > abi.MaxSectorNumber {
			return xc.ErrIllegalArgument.Wrapf("sector number greater than maximum")
		}
		var info SectorPreCommitOnChainInfo
		found, err := precommitted.Get(SectorKey(abi.SectorNumber(sectorNo)), &info)
		if err != nil {
			return err
		}
		if !found {
			return xc.ErrNotFound.Wrapf("sector %d not found", sectorNo)
		}
		precommits = append(precommits, &info)
		return nil
	}); err != nil {
		return nil, err
	}
	return precommits, nil
}

// This method gets and returns the requested pre-committed sectors, skipping
// missing sectors.
func (st *State) FindPrecommittedSectors(store adt.Store, sectorNos ...abi.SectorNumber) ([]*SectorPreCommitOnChainInfo, error) {
	precommitted, err := adt.AsMap(store, st.PreCommittedSectors, builtin.DefaultHamtBitwidth)
	if err != nil {
		return nil, err
	}

	result := make([]*SectorPreCommitOnChainInfo, 0, len(sectorNos))

	for _, sectorNo := range sectorNos {
		var info SectorPreCommitOnChainInfo
		found, err := precommitted.Get(SectorKey(sectorNo), &info)
		if err != nil {
			return nil, xerrors.Errorf("failed to load precommitment for %v: %w", sectorNo, err)
		}
		if !found {
			// TODO #564 log: "failed to get precommitted sector on sector %d, dropping from prove commit set"
			continue
		}
		result = append(result, &info)
	}

	return result, nil
}

func (st *State) DeletePrecommittedSectors(store adt.Store, sectorNos ...abi.SectorNumber) error {
	precommitted, err := adt.AsMap(store, st.PreCommittedSectors, builtin.DefaultHamtBitwidth)
	if err != nil {
		return err
	}

	for _, sectorNo := range sectorNos {
		err = precommitted.Delete(SectorKey(sectorNo))
		if err != nil {
			return xerrors.Errorf("failed to delete precommitment for %v: %w", sectorNo, err)
		}
	}
	st.PreCommittedSectors, err = precommitted.Root()
	return err
}

func (st *State) HasSectorNo(store adt.Store, sectorNo abi.SectorNumber) (bool, error) {
	sectors, err := LoadSectors(store, st.Sectors)
	if err != nil {
		return false, err
	}

	_, found, err := sectors.Get(sectorNo)
	if err != nil {
		return false, xerrors.Errorf("failed to get sector %v: %w", sectorNo, err)
	}
	return found, nil
}

func (st *State) PutSectors(store adt.Store, newSectors ...*SectorOnChainInfo) error {
	sectors, err := LoadSectors(store, st.Sectors)
	if err != nil {
		return xerrors.Errorf("failed to load sectors: %w", err)
	}

	err = sectors.Store(newSectors...)
	if err != nil {
		return err
	}

	st.Sectors, err = sectors.Root()
	if err != nil {
		return xerrors.Errorf("failed to persist sectors: %w", err)
	}
	return nil
}

func (st *State) GetSector(store adt.Store, sectorNo abi.SectorNumber) (*SectorOnChainInfo, bool, error) {
	sectors, err := LoadSectors(store, st.Sectors)
	if err != nil {
		return nil, false, err
	}

	return sectors.Get(sectorNo)
}

func (st *State) DeleteSectors(store adt.Store, sectorNos bitfield.BitField) error {
	sectors, err := LoadSectors(store, st.Sectors)
	if err != nil {
		return err
	}
	err = sectorNos.ForEach(func(sectorNo uint64) error {
		if err = sectors.Delete(sectorNo); err != nil {
			return xerrors.Errorf("failed to delete sector %v: %w", sectorNos, err)
		}
		return nil
	})
	if err != nil {
		return err
	}

	st.Sectors, err = sectors.Root()
	return err
}

// Iterates sectors.
// The pointer provided to the callback is not safe for re-use. Copy the pointed-to value in full to hold a reference.
func (st *State) ForEachSector(store adt.Store, f func(*SectorOnChainInfo)) error {
	sectors, err := LoadSectors(store, st.Sectors)
	if err != nil {
		return err
	}
	var sector SectorOnChainInfo
	return sectors.ForEach(&sector, func(idx int64) error {
		f(&sector)
		return nil
	})
}

func (st *State) FindSector(store adt.Store, sno abi.SectorNumber) (uint64, uint64, error) {
	deadlines, err := st.LoadDeadlines(store)
	if err != nil {
		return 0, 0, err
	}
	return FindSector(store, deadlines, sno)
}

// Assign new sectors to deadlines.
func (st *State) AssignSectorsToDeadlines(
	store adt.Store, currentEpoch abi.ChainEpoch, sectors []*SectorOnChainInfo, partitionSize uint64, sectorSize abi.SectorSize,
) error {
	deadlines, err := st.LoadDeadlines(store)
	if err != nil {
		return err
	}

	// Sort sectors by number to get better runs in partition bitfields.
	sort.Slice(sectors, func(i, j int) bool {
		return sectors[i].SectorNumber < sectors[j].SectorNumber
	})

	var deadlineArr [WPoStPeriodDeadlines]*Deadline
	if err = deadlines.ForEach(store, func(idx uint64, dl *Deadline) error {
		// Skip deadlines that aren't currently mutable.
		if deadlineIsMutable(st.CurrentProvingPeriodStart(currentEpoch), idx, currentEpoch) {
			deadlineArr[int(idx)] = dl
		}
		return nil
	}); err != nil {
		return err
	}

	deadlineToSectors, err := assignDeadlines(MaxPartitionsPerDeadline, partitionSize, &deadlineArr, sectors)
	if err != nil {
		return xerrors.Errorf("failed to assign sectors to deadlines: %w", err)
	}

	for dlIdx, deadlineSectors := range deadlineToSectors {
		if len(deadlineSectors) == 0 {
			continue
		}

		quant := st.QuantSpecForDeadline(uint64(dlIdx))
		dl := deadlineArr[dlIdx]

		// The power returned from AddSectors is ignored because it's not activated (proven) yet.
		proven := false
		if _, err := dl.AddSectors(store, partitionSize, proven, deadlineSectors, sectorSize, quant); err != nil {
			return err
		}

		if err := deadlines.UpdateDeadline(store, uint64(dlIdx), dl); err != nil {
			return err
		}
	}

	if err := st.SaveDeadlines(store, deadlines); err != nil {
		return err
	}
	return nil
}

// Pops up to max early terminated sectors from all deadlines.
//
// Returns hasMore if we still have more early terminations to process.
func (st *State) PopEarlyTerminations(store adt.Store, maxPartitions, maxSectors uint64) (result TerminationResult, hasMore bool, err error) {
	stopErr := xerrors.New("stop error")

	// Anything to do? This lets us avoid loading the deadlines if there's nothing to do.
	noEarlyTerminations, err := st.EarlyTerminations.IsEmpty()
	if err != nil {
		return TerminationResult{}, false, xerrors.Errorf("failed to count deadlines with early terminations: %w", err)
	} else if noEarlyTerminations {
		return TerminationResult{}, false, nil
	}

	// Load deadlines
	deadlines, err := st.LoadDeadlines(store)
	if err != nil {
		return TerminationResult{}, false, xerrors.Errorf("failed to load deadlines: %w", err)
	}

	// Process early terminations.
	if err = st.EarlyTerminations.ForEach(func(dlIdx uint64) error {
		// Load deadline + partitions.
		dl, err := deadlines.LoadDeadline(store, dlIdx)
		if err != nil {
			return xerrors.Errorf("failed to load deadline %d: %w", dlIdx, err)
		}

		deadlineResult, more, err := dl.PopEarlyTerminations(store, maxPartitions-result.PartitionsProcessed, maxSectors-result.SectorsProcessed)
		if err != nil {
			return xerrors.Errorf("failed to pop early terminations for deadline %d: %w", dlIdx, err)
		}

		err = result.Add(deadlineResult)
		if err != nil {
			return xerrors.Errorf("failed to merge result from popping early terminations from deadline: %w", err)
		}

		if !more {
			// safe to do while iterating.
			st.EarlyTerminations.Unset(dlIdx)
		}

		// Save the deadline
		err = deadlines.UpdateDeadline(store, dlIdx, dl)
		if err != nil {
			return xerrors.Errorf("failed to store deadline %d: %w", dlIdx, err)
		}

		if result.BelowLimit(maxPartitions, maxSectors) {
			return nil
		}

		return stopErr
	}); err != nil && err != stopErr {
		return TerminationResult{}, false, xerrors.Errorf("failed to walk early terminations bitfield for deadlines: %w", err)
	}

	// Save back the deadlines.
	err = st.SaveDeadlines(store, deadlines)
	if err != nil {
		return TerminationResult{}, false, xerrors.Errorf("failed to save deadlines: %w", err)
	}

	// Ok, check to see if we've handled all early terminations.
	noEarlyTerminations, err = st.EarlyTerminations.IsEmpty()
	if err != nil {
		return TerminationResult{}, false, xerrors.Errorf("failed to count remaining early terminations deadlines")
	}

	return result, !noEarlyTerminations, nil
}

// Returns an error if the target sector cannot be found, or some other bad state is reached.
// Returns false if the target sector is faulty, terminated, or unproven
// Returns true otherwise
func (st *State) CheckSectorActive(store adt.Store, dlIdx, pIdx uint64, sector abi.SectorNumber, requireProven bool) (bool, error) {
	dls, err := st.LoadDeadlines(store)
	if err != nil {
		return false, err
	}

	dl, err := dls.LoadDeadline(store, dlIdx)
	if err != nil {
		return false, err
	}

	partition, err := dl.LoadPartition(store, pIdx)
	if err != nil {
		return false, err
	}

	if exists, err := partition.Sectors.IsSet(uint64(sector)); err != nil {
		return false, xc.ErrIllegalState.Wrapf("failed to decode sectors bitfield (deadline %d, partition %d): %w", dlIdx, pIdx, err)
	} else if !exists {
		return false, xc.ErrNotFound.Wrapf("sector %d not a member of partition %d, deadline %d", sector, pIdx, dlIdx)
	}

	if faulty, err := partition.Faults.IsSet(uint64(sector)); err != nil {
		return false, xc.ErrIllegalState.Wrapf("failed to decode faults bitfield (deadline %d, partition %d): %w", dlIdx, pIdx, err)
	} else if faulty {
		return false, nil
	}

	if terminated, err := partition.Terminated.IsSet(uint64(sector)); err != nil {
		return false, xc.ErrIllegalState.Wrapf("failed to decode terminated bitfield (deadline %d, partition %d): %w", dlIdx, pIdx, err)
	} else if terminated {
		return false, nil
	}

	if unproven, err := partition.Unproven.IsSet(uint64(sector)); err != nil {
		return false, xc.ErrIllegalState.Wrapf("failed to decode unproven bitfield (deadline %d, partition %d): %w", dlIdx, pIdx, err)
	} else if unproven && requireProven {
		return false, nil
	}

	return true, nil
}

// Loads sector info for a sequence of sectors.
func (st *State) LoadSectorInfos(store adt.Store, sectors bitfield.BitField) ([]*SectorOnChainInfo, error) {
	sectorsArr, err := LoadSectors(store, st.Sectors)
	if err != nil {
		return nil, err
	}
	return sectorsArr.Load(sectors)
}

func (st *State) LoadDeadlines(store adt.Store) (*Deadlines, error) {
	var deadlines Deadlines
	if err := store.Get(store.Context(), st.Deadlines, &deadlines); err != nil {
		return nil, xc.ErrIllegalState.Wrapf("failed to load deadlines (%s): %w", st.Deadlines, err)
	}

	return &deadlines, nil
}

func (st *State) SaveDeadlines(store adt.Store, deadlines *Deadlines) error {
	c, err := store.Put(store.Context(), deadlines)
	if err != nil {
		return err
	}
	st.Deadlines = c
	return nil
}

// LoadVestingFunds loads the vesting funds table from the store
func (st *State) LoadVestingFunds(store adt.Store) (*VestingFunds, error) {
	var funds VestingFunds
	if err := store.Get(store.Context(), st.VestingFunds, &funds); err != nil {
		return nil, xerrors.Errorf("failed to load vesting funds (%s): %w", st.VestingFunds, err)
	}

	return &funds, nil
}

// SaveVestingFunds saves the vesting table to the store
func (st *State) SaveVestingFunds(store adt.Store, funds *VestingFunds) error {
	c, err := store.Put(store.Context(), funds)
	if err != nil {
		return err
	}
	st.VestingFunds = c
	return nil
}

// Return true when the miner actor needs to continue scheduling deadline crons
func (st *State) ContinueDeadlineCron() bool {
	return !st.PreCommitDeposits.IsZero() ||
		!st.InitialPledge.IsZero() ||
		!st.LockedFunds.IsZero()
}

//
// Funds and vesting
//

func (st *State) AddPreCommitDeposit(amount abi.TokenAmount) error {
	newTotal := big.Add(st.PreCommitDeposits, amount)
	if newTotal.LessThan(big.Zero()) {
		return xerrors.Errorf("negative pre-commit deposit %v after adding %v to prior %v", newTotal, amount, st.PreCommitDeposits)
	}
	st.PreCommitDeposits = newTotal
	return nil
}

func (st *State) AddInitialPledge(amount abi.TokenAmount) error {
	newTotal := big.Add(st.InitialPledge, amount)
	if newTotal.LessThan(big.Zero()) {
		return xerrors.Errorf("negative initial pledge %v after adding %v to prior %v", newTotal, amount, st.InitialPledge)
	}
	st.InitialPledge = newTotal
	return nil
}

// AddLockedFunds first vests and unlocks the vested funds AND then locks the given funds in the vesting table.
func (st *State) AddLockedFunds(store adt.Store, currEpoch abi.ChainEpoch, vestingSum abi.TokenAmount, spec *VestSpec) (vested abi.TokenAmount, err error) {
	if vestingSum.LessThan(big.Zero()) {
		return big.Zero(), xerrors.Errorf("negative amount to lock %s", vestingSum)
	}

	vestingFunds, err := st.LoadVestingFunds(store)
	if err != nil {
		return big.Zero(), xerrors.Errorf("failed to load vesting funds: %w", err)
	}

	// unlock vested funds first
	amountUnlocked := vestingFunds.unlockVestedFunds(currEpoch)
	st.LockedFunds = big.Sub(st.LockedFunds, amountUnlocked)
	if st.LockedFunds.LessThan(big.Zero()) {
		return big.Zero(), xerrors.Errorf("negative locked funds %v after unlocking %v", st.LockedFunds, amountUnlocked)
	}

	// add locked funds now
	vestingFunds.addLockedFunds(currEpoch, vestingSum, st.ProvingPeriodStart, spec)
	st.LockedFunds = big.Add(st.LockedFunds, vestingSum)

	// save the updated vesting table state
	if err := st.SaveVestingFunds(store, vestingFunds); err != nil {
		return big.Zero(), xerrors.Errorf("failed to save vesting funds: %w", err)
	}

	return amountUnlocked, nil
}

// ApplyPenalty adds the provided penalty to fee debt.
func (st *State) ApplyPenalty(penalty abi.TokenAmount) error {
	if penalty.LessThan(big.Zero()) {
		return xerrors.Errorf("applying negative penalty %v not allowed", penalty)
	}
	st.FeeDebt = big.Add(st.FeeDebt, penalty)
	return nil
}

// Draws from vesting table and unlocked funds to repay up to the fee debt.
// Returns the amount unlocked from the vesting table and the amount taken from
// current balance. If the fee debt exceeds the total amount available for repayment
// the fee debt field is updated to track the remaining debt.  Otherwise it is set to zero.
func (st *State) RepayPartialDebtInPriorityOrder(store adt.Store, currEpoch abi.ChainEpoch, currBalance abi.TokenAmount) (fromVesting abi.TokenAmount, fromBalance abi.TokenAmount, err error) {
	unlockedBalance, err := st.GetUnlockedBalance(currBalance)
	if err != nil {
		return big.Zero(), big.Zero(), err
	}

	// Pay fee debt with locked funds first
	fromVesting, err = st.UnlockUnvestedFunds(store, currEpoch, st.FeeDebt)
	if err != nil {
		return abi.NewTokenAmount(0), abi.NewTokenAmount(0), err
	}

	// We should never unlock more than the debt we need to repay
	if fromVesting.GreaterThan(st.FeeDebt) {
		return big.Zero(), big.Zero(), xerrors.Errorf("unlocked more vesting funds %v than required for debt %v", fromVesting, st.FeeDebt)
	}
	st.FeeDebt = big.Sub(st.FeeDebt, fromVesting)

	fromBalance = big.Min(unlockedBalance, st.FeeDebt)
	st.FeeDebt = big.Sub(st.FeeDebt, fromBalance)

	return fromVesting, fromBalance, nil

}

// Repays the full miner actor fee debt.  Returns the amount that must be
// burnt and an error if there are not sufficient funds to cover repayment.
// Miner state repays from unlocked funds and fails if unlocked funds are insufficient to cover fee debt.
// FeeDebt will be zero after a successful call.
func (st *State) repayDebts(currBalance abi.TokenAmount) (abi.TokenAmount, error) {
	unlockedBalance, err := st.GetUnlockedBalance(currBalance)
	if err != nil {
		return big.Zero(), err
	}
	if unlockedBalance.LessThan(st.FeeDebt) {
		return big.Zero(), xc.ErrInsufficientFunds.Wrapf("unlocked balance can not repay fee debt (%v < %v)", unlockedBalance, st.FeeDebt)
	}
	debtToRepay := st.FeeDebt
	st.FeeDebt = big.Zero()
	return debtToRepay, nil
}

// Unlocks an amount of funds that have *not yet vested*, if possible.
// The soonest-vesting entries are unlocked first.
// Returns the amount actually unlocked.
func (st *State) UnlockUnvestedFunds(store adt.Store, currEpoch abi.ChainEpoch, target abi.TokenAmount) (abi.TokenAmount, error) {
	// Nothing to unlock, don't bother loading any state.
	if target.IsZero() || st.LockedFunds.IsZero() {
		return big.Zero(), nil
	}

	vestingFunds, err := st.LoadVestingFunds(store)
	if err != nil {
		return big.Zero(), xerrors.Errorf("failed tp load vesting funds: %w", err)
	}

	amountUnlocked := vestingFunds.unlockUnvestedFunds(currEpoch, target)

	st.LockedFunds = big.Sub(st.LockedFunds, amountUnlocked)
	if st.LockedFunds.LessThan(big.Zero()) {
		return big.Zero(), xerrors.Errorf("negative locked funds %v after unlocking %v", st.LockedFunds, amountUnlocked)
	}

	if err := st.SaveVestingFunds(store, vestingFunds); err != nil {
		return big.Zero(), xerrors.Errorf("failed to save vesting funds: %w", err)
	}

	return amountUnlocked, nil
}

// Unlocks all vesting funds that have vested before the provided epoch.
// Returns the amount unlocked.
func (st *State) UnlockVestedFunds(store adt.Store, currEpoch abi.ChainEpoch) (abi.TokenAmount, error) {
	// Short-circuit to avoid loading vesting funds if we don't have any.
	if st.LockedFunds.IsZero() {
		return big.Zero(), nil
	}

	vestingFunds, err := st.LoadVestingFunds(store)
	if err != nil {
		return big.Zero(), xerrors.Errorf("failed to load vesting funds: %w", err)
	}

	amountUnlocked := vestingFunds.unlockVestedFunds(currEpoch)
	st.LockedFunds = big.Sub(st.LockedFunds, amountUnlocked)
	if st.LockedFunds.LessThan(big.Zero()) {
		return big.Zero(), xerrors.Errorf("vesting cause locked funds negative %v", st.LockedFunds)
	}

	err = st.SaveVestingFunds(store, vestingFunds)
	if err != nil {
		return big.Zero(), xerrors.Errorf("failed to save vesing funds: %w", err)
	}

	return amountUnlocked, nil
}

// CheckVestedFunds returns the amount of vested funds that have vested before the provided epoch.
func (st *State) CheckVestedFunds(store adt.Store, currEpoch abi.ChainEpoch) (abi.TokenAmount, error) {
	vestingFunds, err := st.LoadVestingFunds(store)
	if err != nil {
		return big.Zero(), xerrors.Errorf("failed to load vesting funds: %w", err)
	}

	amountVested := abi.NewTokenAmount(0)

	for i := range vestingFunds.Funds {
		vf := vestingFunds.Funds[i]
		epoch := vf.Epoch
		amount := vf.Amount

		if epoch >= currEpoch {
			break
		}

		amountVested = big.Add(amountVested, amount)
	}

	return amountVested, nil
}

// Unclaimed funds that are not locked -- includes free funds and does not
// account for fee debt.  Always greater than or equal to zero
func (st *State) GetUnlockedBalance(actorBalance abi.TokenAmount) (abi.TokenAmount, error) {
	unlockedBalance := big.Subtract(actorBalance, st.LockedFunds, st.PreCommitDeposits, st.InitialPledge)
	if unlockedBalance.LessThan(big.Zero()) {
		return big.Zero(), xerrors.Errorf("negative unlocked balance %v", unlockedBalance)
	}
	return unlockedBalance, nil
}

// Unclaimed funds.  Actor balance - (locked funds, precommit deposit, initial pledge, fee debt)
// Can go negative if the miner is in IP debt
func (st *State) GetAvailableBalance(actorBalance abi.TokenAmount) (abi.TokenAmount, error) {
	unlockedBalance, err := st.GetUnlockedBalance(actorBalance)
	if err != nil {
		return big.Zero(), err
	}
	return big.Subtract(unlockedBalance, st.FeeDebt), nil
}

func (st *State) CheckBalanceInvariants(balance abi.TokenAmount) error {
	if st.PreCommitDeposits.LessThan(big.Zero()) {
		return xerrors.Errorf("pre-commit deposit is negative: %v", st.PreCommitDeposits)
	}
	if st.LockedFunds.LessThan(big.Zero()) {
		return xerrors.Errorf("locked funds is negative: %v", st.LockedFunds)
	}
	if st.InitialPledge.LessThan(big.Zero()) {
		return xerrors.Errorf("initial pledge is negative: %v", st.InitialPledge)
	}
	if st.FeeDebt.LessThan(big.Zero()) {
		return xerrors.Errorf("fee debt is negative: %v", st.FeeDebt)
	}
	minBalance := big.Sum(st.PreCommitDeposits, st.LockedFunds, st.InitialPledge)
	if balance.LessThan(minBalance) {
		return xerrors.Errorf("balance %v below required %v", balance, minBalance)
	}
	return nil
}

func (st *State) IsDebtFree() bool {
	return st.FeeDebt.LessThanEqual(big.Zero())
}

// pre-commit clean up
func (st *State) QuantSpecEveryDeadline() builtin.QuantSpec {
	return builtin.NewQuantSpec(WPoStChallengeWindow, st.ProvingPeriodStart)
}

func (st *State) AddPreCommitCleanUps(store adt.Store, cleanUpEvents map[abi.ChainEpoch][]uint64) error {
	// Load BitField Queue for sector expiry
	quant := st.QuantSpecEveryDeadline()
	queue, err := LoadBitfieldQueue(store, st.PreCommittedSectorsCleanUp, quant, PrecommitCleanUpAmtBitwidth)
	if err != nil {
		return xerrors.Errorf("failed to load pre-commit clean up queue: %w", err)
	}

	// Sort the epoch keys for stable iteration when manipulating the queue
	epochs := make([]abi.ChainEpoch, len(cleanUpEvents))
	i := 0
	for expireEpoch := range cleanUpEvents { // nolint: nomaprange
		epochs[i] = expireEpoch
		i++
	}
	sort.Slice(epochs, func(i, j int) bool {
		return epochs[i] < epochs[j]
	})

	for _, cleanUpEpoch := range epochs {
		if err := queue.AddToQueueValues(cleanUpEpoch, cleanUpEvents[cleanUpEpoch]...); err != nil {
			return xerrors.Errorf("failed to add pre-commit sector clean up to queue: %w", err)
		}
	}

	st.PreCommittedSectorsCleanUp, err = queue.Root()
	if err != nil {
		return xerrors.Errorf("failed to save pre-commit sector queue: %w", err)
	}
	return nil
}

func (st *State) CleanUpExpiredPreCommits(store adt.Store, currEpoch abi.ChainEpoch) (depositToBurn abi.TokenAmount, err error) {
	depositToBurn = abi.NewTokenAmount(0)

	// cleanup expired pre-committed sectors
	cleanUpQ, err := LoadBitfieldQueue(store, st.PreCommittedSectorsCleanUp, st.QuantSpecEveryDeadline(), PrecommitCleanUpAmtBitwidth)
	if err != nil {
		return depositToBurn, xerrors.Errorf("failed to load sector expiry queue: %w", err)
	}

	sectors, modified, err := cleanUpQ.PopUntil(currEpoch)
	if err != nil {
		return depositToBurn, xerrors.Errorf("failed to pop expired sectors: %w", err)
	}

	if modified {
		st.PreCommittedSectorsCleanUp, err = cleanUpQ.Root()
		if err != nil {
			return depositToBurn, xerrors.Errorf("failed to save pre commit clean up queue: %w", err)
		}
	}

	var precommitsToDelete []abi.SectorNumber
	if err = sectors.ForEach(func(i uint64) error {
		sectorNo := abi.SectorNumber(i)
		sector, found, err := st.GetPrecommittedSector(store, sectorNo)
		if err != nil {
			return err
		}
		if !found {
			// already committed/deleted
			return nil
		}

		// mark it for deletion
		precommitsToDelete = append(precommitsToDelete, sectorNo)

		// increment deposit to burn
		depositToBurn = big.Add(depositToBurn, sector.PreCommitDeposit)
		return nil
	}); err != nil {
		return big.Zero(), xerrors.Errorf("failed to check pre-commit expiries: %w", err)
	}

	// Actually delete it.
	if len(precommitsToDelete) > 0 {
		if err := st.DeletePrecommittedSectors(store, precommitsToDelete...); err != nil {
			return big.Zero(), fmt.Errorf("failed to delete pre-commits: %w", err)
		}
	}

	st.PreCommitDeposits = big.Sub(st.PreCommitDeposits, depositToBurn)
	if st.PreCommitDeposits.LessThan(big.Zero()) {
		return big.Zero(), xerrors.Errorf("pre-commit clean up caused negative deposits: %v", st.PreCommitDeposits)
	}

	// This deposit was locked separately to pledge collateral so there's no pledge change here.
	return depositToBurn, nil
}

type AdvanceDeadlineResult struct {
	PledgeDelta           abi.TokenAmount
	PowerDelta            PowerPair
	PreviouslyFaultyPower PowerPair // Power that was faulty before this advance (including recovering)
	DetectedFaultyPower   PowerPair // Power of new faults and failed recoveries
	TotalFaultyPower      PowerPair // Total faulty power after detecting faults (before expiring sectors)
	// Note that failed recovery power is included in both PreviouslyFaultyPower and DetectedFaultyPower,
	// so TotalFaultyPower is not simply their sum.
}

// AdvanceDeadline advances the deadline. It:
// - Processes expired sectors.
// - Handles missed proofs.
// - Returns the changes to power & pledge, and faulty power (both declared and undeclared).
func (st *State) AdvanceDeadline(store adt.Store, currEpoch abi.ChainEpoch) (*AdvanceDeadlineResult, error) {
	pledgeDelta := abi.NewTokenAmount(0)
	powerDelta := NewPowerPairZero()

	var totalFaultyPower PowerPair
	detectedFaultyPower := NewPowerPairZero()

	// Note: Use dlInfo.Last() rather than rt.CurrEpoch unless certain
	// of the desired semantics. In the past, this method would sometimes be
	// invoked late due to skipped blocks. This is no longer the case, but
	// we still use dlInfo.Last().
	dlInfo := st.DeadlineInfo(currEpoch)

	// Return early if the proving period hasn't started. While actors v2
	// sets the proving period start into the past so this case can never
	// happen, v1:
	//
	// 1. Sets the proving period in the future.
	// 2. Schedules the first cron event one epoch _before_ the proving
	//    period start.
	//
	// At this point, no proofs have been submitted so we can't check them.
	if !dlInfo.PeriodStarted() {
		return &AdvanceDeadlineResult{
			pledgeDelta,
			powerDelta,
			NewPowerPairZero(),
			NewPowerPairZero(),
			NewPowerPairZero(),
		}, nil
	}

	// Advance to the next deadline (in case we short-circuit below).
	// Maintaining this state info is a legacy operation no longer required for code correctness
	st.CurrentDeadline = (dlInfo.Index + 1) % WPoStPeriodDeadlines
	if st.CurrentDeadline == 0 {
		st.ProvingPeriodStart = dlInfo.PeriodStart + WPoStProvingPeriod
	}

	deadlines, err := st.LoadDeadlines(store)
	if err != nil {
		return nil, xerrors.Errorf("failed to load deadlines: %w", err)
	}
	deadline, err := deadlines.LoadDeadline(store, dlInfo.Index)
	if err != nil {
		return nil, xerrors.Errorf("failed to load deadline %d: %w", dlInfo.Index, err)
	}

	previouslyFaultyPower := deadline.FaultyPower

	// No live sectors in this deadline, nothing to do.
	if live, err := deadline.IsLive(); err != nil {
		return nil, xerrors.Errorf("failed to determine if miner is live: %w", err)
	} else if !live {
		return &AdvanceDeadlineResult{
			pledgeDelta,
			powerDelta,
			previouslyFaultyPower,
			detectedFaultyPower,
			deadline.FaultyPower,
		}, nil
	}

	quant := QuantSpecForDeadline(dlInfo)
	{
		// Detect and penalize missing proofs.
		faultExpiration := dlInfo.Last() + FaultMaxAge

		// detectedFaultyPower is new faults and failed recoveries
		powerDelta, detectedFaultyPower, err = deadline.ProcessDeadlineEnd(store, quant, faultExpiration, st.Sectors)
		if err != nil {
			return nil, xerrors.Errorf("failed to process end of deadline %d: %w", dlInfo.Index, err)
		}
		// Capture deadline's faulty power after new faults have been detected, but before it is
		// dropped along with faulty sectors expiring this round.
		totalFaultyPower = deadline.FaultyPower
	}
	{
		// Expire sectors that are due, either for on-time expiration or "early" faulty-for-too-long.
		expired, err := deadline.PopExpiredSectors(store, dlInfo.Last(), quant)
		if err != nil {
			return nil, xerrors.Errorf("failed to load expired sectors: %w", err)
		}

		// Release pledge requirements for the sectors expiring on-time.
		// Pledge for the sectors expiring early is retained to support the termination fee that will be assessed
		// when the early termination is processed.
		pledgeDelta = big.Sub(pledgeDelta, expired.OnTimePledge)
		if err = st.AddInitialPledge(expired.OnTimePledge.Neg()); err != nil {
			return nil, xerrors.Errorf("failed to reduce %v initial pledge for expiring sectors: %w", expired.OnTimePledge, err)
		}

		// Record reduction in power of the amount of expiring active power.
		// Faulty power has already been lost, so the amount expiring can be excluded from the delta.
		powerDelta = powerDelta.Sub(expired.ActivePower)

		// Record deadlines with early terminations. While this
		// bitfield is non-empty, the miner is locked until they
		// pay the fee.
		noEarlyTerminations, err := expired.EarlySectors.IsEmpty()
		if err != nil {
			return nil, xerrors.Errorf("failed to count early terminations: %w", err)
		}
		if !noEarlyTerminations {
			st.EarlyTerminations.Set(dlInfo.Index)
		}
	}

	// Save new deadline state.
	err = deadlines.UpdateDeadline(store, dlInfo.Index, deadline)
	if err != nil {
		return nil, xerrors.Errorf("failed to update deadline %d: %w", dlInfo.Index, err)
	}

	err = st.SaveDeadlines(store, deadlines)
	if err != nil {
		return nil, xerrors.Errorf("failed to save deadlines: %w", err)
	}

	// Compute penalties all together.
	// Be very careful when changing these as any changes can affect rounding.
	return &AdvanceDeadlineResult{
		PledgeDelta:           pledgeDelta,
		PowerDelta:            powerDelta,
		PreviouslyFaultyPower: previouslyFaultyPower,
		DetectedFaultyPower:   detectedFaultyPower,
		TotalFaultyPower:      totalFaultyPower,
	}, nil
}

//
// Misc helpers
//

func SectorKey(e abi.SectorNumber) abi.Keyer {
	return abi.UIntKey(uint64(e))
}

func init() {
	// Check that ChainEpoch is indeed an unsigned integer to confirm that SectorKey is making the right interpretation.
	var e abi.SectorNumber
	if reflect.TypeOf(e).Kind() != reflect.Uint64 {
		panic("incorrect sector number encoding")
	}
}