diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 1612f44e4ec..adf5bc93de5 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -9093,7 +9093,8 @@ do_pg_start_backup(const char *backupidstr, bool fast, char **labelfile)
 						 errmsg("could not create file \"%s\": %m",
 								BACKUP_LABEL_FILE)));
 			fwrite(labelfbuf.data, labelfbuf.len, 1, fp);
-			if (fflush(fp) || ferror(fp) || FreeFile(fp))
+
+			if (fflush(fp) || ferror(fp) || pg_fsync(fileno(fp)) != 0 || FreeFile(fp))
 				ereport(ERROR,
 						(errcode_for_file_access(),
 						 errmsg("could not write file \"%s\": %m",