diff --git a/record/log_writer.go b/record/log_writer.go
index f31aca5214..fe9a0d907d 100644
--- a/record/log_writer.go
+++ b/record/log_writer.go
@@ -538,7 +538,7 @@ func (w *LogWriter) flushBlock(b *block) error {
 	if _, err := w.w.Write(b.buf[b.flushed:]); err != nil {
 		return err
 	}
-	b.written = 0
+	atomic.StoreInt32(&b.written, 0)
 	b.flushed = 0
 	w.free.Lock()
 	w.free.blocks = append(w.free.blocks, b)
@@ -657,25 +657,25 @@ func (w *LogWriter) SyncRecord(p []byte, wg *sync.WaitGroup, err *error) (int64,
 		f.ready.Signal()
 	}
 
-	offset := w.blockNum*blockSize + int64(w.block.written)
 	// Note that we don't return w.err here as a concurrent call to Close would
 	// race with our read. That's ok because the only error we could be seeing is
 	// one to syncing for which the caller can receive notification of by passing
 	// in a non-nil err argument.
-	return offset, nil
+	return w.Size(), nil
 }
 
 // Size returns the current size of the file.
 // External synchronisation provided by commitPipeline.mu.
 func (w *LogWriter) Size() int64 {
-	return w.blockNum*blockSize + int64(w.block.written)
+	written := atomic.LoadInt32(&w.block.written)
+	return w.blockNum*blockSize + int64(written)
 }
 
 func (w *LogWriter) emitEOFTrailer() {
 	// Write a recyclable chunk header with a different log number.  Readers
 	// will treat the header as EOF when the log number does not match.
 	b := w.block
-	i := b.written
+	i := atomic.LoadInt32(&w.block.written)
 	binary.LittleEndian.PutUint32(b.buf[i+0:i+4], 0) // CRC
 	binary.LittleEndian.PutUint16(b.buf[i+4:i+6], 0) // Size
 	b.buf[i+6] = recyclableFullChunkType
@@ -685,7 +685,7 @@ func (w *LogWriter) emitEOFTrailer() {
 
 func (w *LogWriter) emitFragment(n int, p []byte) []byte {
 	b := w.block
-	i := b.written
+	i := atomic.LoadInt32(&w.block.written)
 	first := n == 0
 	last := blockSize-i-recyclableHeaderSize >= int32(len(p))
 
@@ -711,10 +711,11 @@ func (w *LogWriter) emitFragment(n int, p []byte) []byte {
 	binary.LittleEndian.PutUint16(b.buf[i+4:i+6], uint16(r))
 	atomic.StoreInt32(&b.written, j)
 
-	if blockSize-b.written < recyclableHeaderSize {
+	// NB: j = b.written
+	if blockSize-j < recyclableHeaderSize {
 		// There is no room for another fragment in the block, so fill the
 		// remaining bytes with zeros and queue the block for flushing.
-		for i := b.written; i < blockSize; i++ {
+		for i := j; i < blockSize; i++ {
 			b.buf[i] = 0
 		}
 		w.queueBlock()