Comment 0 for bug 1840640

ARM has two sync_file_range syscalls, sync_file_range and sync_file_range2. The former is apparently not used, and glibc calls the latter whenever a userspace program calls sync_file_range. I'm guessing systemd-nspawn doesn't know this, because the follow code consistently fails in an nspawn container on ARM:

#define _GNU_SOURCE
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>

void main()
{
        int f = open("/tmp/syncrange.test",O_CREAT|O_RDWR,0666);
        int r=sync_file_range(f, 0, 0, 0);
        if (r)
                perror("sync_file_range");
        close(f);
}

This seems to be causing problems specifically for borg(backup) and postgres:

https://github.com/borgbackup/borg/issues/4710
https://www.postgresql.org/message-id/flat/CA%2BhUKG%2BydOUT4zjxb6QmJWy8U9WbC-q%2BJWV7wLsEY9Df%3Dmw0Mw%40mail.gmail.com#ac8f14897647dc7eae3c7e7cbed36d93

The solution should be to cherrypick https://github.com/systemd/systemd/pull/13352, I am currently waiting for systemd to rebuild on a slow ARM box. Any chance of an SRU?

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: systemd-container 237-3ubuntu10.24
Uname: Linux 4.14.66+ armv7l
NonfreeKernelModules: extcon_usb_gpio
ApportVersion: 2.20.9-0ubuntu7.7
Architecture: armhf
Date: Mon Aug 19 11:10:48 2019
ProcEnviron:
 TERM=screen
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: systemd
UpgradeStatus: No upgrade log present (probably fresh install)