--- a/linux/blkdev.c
+++ b/linux/blkdev.c
@@ -256,6 +256,15 @@
 	sync_check(bio, ret);
 }
 
+#ifndef __GLIBC__
+/* musl lacks this */
+ssize_t pwritev2(int fd, const struct iovec *iov, int count, off_t ofs, int flags)
+{
+	return syscall(SYS_pwritev2, fd, iov, count,
+		(long)(ofs), (long)(ofs>>32), flags);
+}
+#endif
+
 static void sync_write(struct bio *bio, struct iovec * iov, unsigned i)
 {
 	ssize_t ret = pwritev2(bio->bi_bdev->bd_fd, iov, i,
