post: More review addressing

chain/store/store.go

@@ -5,6 +5,7 @@ import (
 	"crypto/sha256"
 	"encoding/json"
 	"fmt"
+	"github.com/filecoin-project/go-lotus/build"
 	"sync"
 
 	amt "github.com/filecoin-project/go-amt-ipld"
@@ -755,6 +756,10 @@ func (cs *ChainStore) GetTipsetByHeight(ctx context.Context, h uint64, ts *types
 		return nil, xerrors.Errorf("looking for tipset with height less than start point")
 	}
 
+	if ts.Height()-h > build.ForkLengthThreshold {
+		log.Warnf("expensive call to GetTipsetByHeight, seeking %d levels", ts.Height()-h)
+	}
+
 	for {
 		mtb := ts.MinTicketBlock()
 		if h >= ts.Height()-uint64(len(mtb.Tickets)) {

storage/miner.go

@@ -250,7 +250,7 @@ func (m *Miner) maybeDoPost(ctx context.Context, ts *types.TipSet) (<-chan error
 		return nil, nil, xerrors.Errorf("failed to get proving period end for miner: %w", err)
 	}
 
-	if ppe < ts.Height() {
+	if ts.Height() > ppe {
 		log.Warnf("skipping post, supplied tipset too high: ppe=%d, ts.H=%d", ppe, ts.Height())
 		return nil, nil, nil
 	}