changes as per review

extern/sector-storage/piece_provider.go

@@ -71,6 +71,9 @@ func (p *pieceProvider) tryReadUnsealedPiece(ctx context.Context, sector storage
 // ReadPiece is used to read an Unsealed piece at the given offset and of the given size from a Sector
 // If an Unsealed sector file exists with the Piece Unsealed in it, we'll use that for the read.
 // Otherwise, we will Unseal a Sealed sector file for the given sector and read the Unsealed piece from it.
+// If we do NOT have an existing unsealed file  containing the given piece thus causing us to schedule an Unseal,
+// the returned boolean parameter will be set to true.
+// If we have an existing unsealed file containing the given piece, the returned boolean will be set to false.
 func (p *pieceProvider) ReadPiece(ctx context.Context, sector storage.SectorRef, offset storiface.UnpaddedByteIndex, size abi.UnpaddedPieceSize, ticket abi.SealRandomness, unsealed cid.Cid) (io.ReadCloser, bool, error) {
 	if err := offset.Valid(); err != nil {
 		return nil, false, xerrors.Errorf("offset is not valid: %w", err)

extern/sector-storage/stores/http_handler.go

@@ -155,7 +155,6 @@ func (handler *FetchHandler) remoteGetSector(w http.ResponseWriter, r *http.Requ
 		}
 	} else {
 		w.Header().Set("Content-Type", "application/octet-stream")
-		w.WriteHeader(200)
 		// will do a ranged read over the file at the given path if the caller has asked for a ranged read in the request headers.
 		http.ServeFile(w, r, path)
 	}

extern/sector-storage/stores/remote.go

@@ -560,13 +560,15 @@ func (r *Remote) Reader(ctx context.Context, s storage.SectorRef, offset, size a
 		return si[i].Weight > si[j].Weight
 	})
 
+	var lastErr error
 	for _, info := range si {
 		for _, url := range info.URLs {
 			// checkAllocated makes a JSON RPC query to a remote worker to determine if it has
 			// unsealed piece in their unsealed sector file.
 			ok, err := r.checkAllocated(ctx, url, s.ProofType, offset, size)
 			if err != nil {
 				log.Warnw("check if remote has piece", "url", url, "error", err)
+				lastErr = err
 				continue
 			}
 			if !ok {
@@ -578,6 +580,7 @@ func (r *Remote) Reader(ctx context.Context, s storage.SectorRef, offset, size a
 			rd, err := r.readRemote(ctx, url, offset, size)
 			if err != nil {
 				log.Warnw("reading from remote", "url", url, "error", err)
+				lastErr = err
 				continue
 			}
 			log.Infof("Read remote %s (+%d,%d)", url, offset, size)
@@ -586,12 +589,15 @@ func (r *Remote) Reader(ctx context.Context, s storage.SectorRef, offset, size a
 	}
 
 	// we couldn't find a unsealed file with the unsealed piece, will return a nil reader.
-	log.Debugf("returning nil reader, did not find unsealed piece for %+v (+%d,%d)", s, offset, size)
+	log.Debugf("returning nil reader, did not find unsealed piece for %+v (+%d,%d), last error=%s", s, offset, size, lastErr)
 	return nil, nil
 }
 
 func (r *Remote) Reserve(ctx context.Context, sid storage.SectorRef, ft storiface.SectorFileType, storageIDs storiface.SectorPaths, overheadTab map[storiface.SectorFileType]int) (func(), error) {
-	panic("not implemented")
+	log.Warnf("reserve called on remote store, sectorID: %v", sid.ID)
+	return func() {
+
+	}, nil
 }
 
 var _ Store = &Remote{}

extern/sector-storage/stores/util_unix.go

@@ -2,6 +2,7 @@ package stores
 
 import (
 	"bytes"
+	"os"
 	"os/exec"
 	"path/filepath"
 	"runtime"
@@ -37,6 +38,10 @@ func move(from, to string) error {
 
 	var cmd *exec.Cmd
 	if runtime.GOOS == "darwin" {
+		if err := os.MkdirAll(toDir, 0777); err != nil {
+			return xerrors.Errorf("failed exec MkdirAll: %s", err)
+		}
+
 		cmd = exec.Command("/usr/bin/env", "mv", from, toDir) // nolint
 	} else {
 		cmd = exec.Command("/usr/bin/env", "mv", "-t", toDir, from) // nolint