diff --git a/extern/sector-storage/piece_reader.go b/extern/sector-storage/piece_reader.go
index d7a3f4e98..882a2a6d9 100644
--- a/extern/sector-storage/piece_reader.go
+++ b/extern/sector-storage/piece_reader.go
@@ -4,6 +4,7 @@ import (
 	"bufio"
 	"context"
 	"io"
+	"sync"
 
 	"github.com/ipfs/go-cid"
 	"go.opencensus.io/stats"
@@ -31,6 +32,7 @@ type pieceReader struct {
 	closed bool
 	seqAt  int64 // next byte to be read by io.Reader
 
+	mu  sync.Mutex
 	r   io.ReadCloser
 	br  *bufio.Reader
 	rAt int64
@@ -62,6 +64,9 @@ func (p *pieceReader) check() error {
 }
 
 func (p *pieceReader) Close() error {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
 	if err := p.check(); err != nil {
 		return err
 	}
@@ -84,16 +89,22 @@ func (p *pieceReader) Close() error {
 }
 
 func (p *pieceReader) Read(b []byte) (int, error) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
 	if err := p.check(); err != nil {
 		return 0, err
 	}
 
-	n, err := p.ReadAt(b, p.seqAt)
+	n, err := p.readAtUnlocked(b, p.seqAt)
 	p.seqAt += int64(n)
 	return n, err
 }
 
 func (p *pieceReader) Seek(offset int64, whence int) (int64, error) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
 	if err := p.check(); err != nil {
 		return 0, err
 	}
@@ -113,6 +124,13 @@ func (p *pieceReader) Seek(offset int64, whence int) (int64, error) {
 }
 
 func (p *pieceReader) ReadAt(b []byte, off int64) (n int, err error) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	return p.readAtUnlocked(b, off)
+}
+
+func (p *pieceReader) readAtUnlocked(b []byte, off int64) (n int, err error) {
 	if err := p.check(); err != nil {
 		return 0, err
 	}