.

wcfs/wcfs.go

@@ -522,7 +522,8 @@ func (bfdata *BigFileData) Read(_ nodefs.File, dest []byte, off int64, fctx *fus
 		blkoff := blkoff
 		blk := blkoff / zbf.blksize
 		wg.Go(func() error {
-			return bfdata.readBlk(ctx, blk, dest[blkoff-aoff:])	// XXX dest.size
+			δ := blkoff-aoff // blk position in dest
+			return bfdata.readBlk(ctx, blk, dest[δ:δ+zbf.blksize])
 		})
 	}
 
@@ -536,6 +537,8 @@ func (bfdata *BigFileData) Read(_ nodefs.File, dest []byte, off int64, fctx *fus
 }
 
 // readBlk serves Read to read 1 ZBlk #blk into destination buffer.
+//
+// len(dest) == blksize.
 func (bfdata *BigFileData) readBlk(ctx context.Context, blk int64, dest []byte) error {
 	// XXX errctx?