lotus/storage/sectorblocks/unsealed.go
2019-08-29 20:55:20 +02:00

100 lines
2.1 KiB
Go

package sectorblocks
import (
"context"
"sync"
logging "github.com/ipfs/go-log"
"github.com/filecoin-project/go-lotus/api"
"github.com/filecoin-project/go-lotus/lib/sectorbuilder"
)
var log = logging.Logger("sectorblocks")
type unsealedBlocks struct {
lk sync.Mutex
sb *sectorbuilder.SectorBuilder
// TODO: Treat this as some sort of cache, one with rather aggressive GC
// TODO: This REALLY, REALLY needs to be on-disk
unsealed map[string][]byte
unsealing map[string]chan struct{}
}
func (ub *unsealedBlocks) getRef(ctx context.Context, refs []api.SealedRef, approveUnseal func() error) ([]byte, error) {
var best api.SealedRef
ub.lk.Lock()
for _, ref := range refs {
b, ok := ub.unsealed[ref.Piece]
if ok {
ub.lk.Unlock()
return b[ref.Offset : ref.Offset+uint64(ref.Size)], nil
}
// TODO: pick unsealing based on how long it's running (or just select all relevant, usually it'll be just one)
_, ok = ub.unsealing[ref.Piece]
if ok {
best = ref
break
}
best = ref
}
ub.lk.Unlock()
b, err := ub.maybeUnseal(ctx, best.Piece, approveUnseal)
if err != nil {
return nil, err
}
return b[best.Offset : best.Offset+uint64(best.Size)], nil
}
func (ub *unsealedBlocks) maybeUnseal(ctx context.Context, pieceKey string, approveUnseal func() error) ([]byte, error) {
ub.lk.Lock()
defer ub.lk.Unlock()
out, ok := ub.unsealed[pieceKey]
if ok {
return out, nil
}
wait, ok := ub.unsealing[pieceKey]
if ok {
ub.lk.Unlock()
select {
case <-wait:
ub.lk.Lock()
// TODO: make sure this is not racy with gc when it's implemented
return ub.unsealed[pieceKey], nil
case <-ctx.Done():
ub.lk.Lock()
return nil, ctx.Err()
}
}
// TODO: doing this under a lock is suboptimal.. but simpler
err := approveUnseal()
if err != nil {
return nil, err
}
ub.unsealing[pieceKey] = make(chan struct{})
ub.lk.Unlock()
log.Infof("Unsealing piece '%s'", pieceKey)
data, err := ub.sb.ReadPieceFromSealedSector(pieceKey)
ub.lk.Lock()
if err != nil {
// TODO: tell subs
log.Error(err)
return nil, err
}
ub.unsealed[pieceKey] = data
close(ub.unsealing[pieceKey])
return data, nil
}