[systemd-devel] Failure to remount / ro (Was: Re: [PATCH 2/4] Adding unmount functions to be used in shutdown)

[Gustavo Sverzut Barbieri]

On Sun, Oct 24, 2010 at 12:41 PM, Michael Biebl <mbiebl at gmail.com> wrote:
> Together with fidencio I tracked down the bug which caused / *not* to
> be remounted ro on shutdown.
>
> The relevant code is in src/umount.c
>
> 2010/10/7  <fidencio at profusion.mobi>:
>> +int umount_all(void) {
>> +        int r;
>> +        LIST_HEAD(MountPoint, mp_list_head);
>> +
>> +        LIST_HEAD_INIT(MountPoint, mp_list_head);
>> +
>> +        r = mount_points_list_get(&mp_list_head);
>> +        if (r < 0)
>> +                goto end;
>> +
>> +        r = mount_points_list_umount(&mp_list_head);
>> +        if (r <= 0)
>> +                goto end;
>
> r is the number of mount points which failed to be unmounted.
> We always skip / in mount_points_list_umount though,
> I.e. if there is no failed unmount attempt, we will never try to remount / ro.
>
> Maybe we should just call mount_points_list_remount_read_only unconditionally.
> or increment the failed counter in mount_points_list_umount if we skip "/"

I guess either we run it unconditionally or we just call the remount
of / to "ro" explicitly if r == 0 (clear I guess)



> +static int mount_points_list_umount(MountPoint **mount_point_list_head) {
> +        MountPoint *mp, *mp_next;
> +        int failed = 0;
> +
> +        LIST_FOREACH_SAFE(mount_point, mp, mp_next, *mount_point_list_head) {
> +                if (streq(mp->path, "/"))
> +                        continue;
>                          ^ add failed++ to make sure / is remounted-ro?

it would be a bit misleading.

-- 
Gustavo Sverzut Barbieri
http://profusion.mobi embedded systems
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