Re: [PATCH] mdadm: Incremental mode creates file for udev rules

[Mariusz Tkaczyk <mtkaczyk@kernel.org>]

On Tue, 25 Mar 2025 15:18:00 -0400
Nigel Croxon <ncroxon@redhat.com> wrote:

> Mounting an md device may fail during boot from mdadm's claim
> on the device not being released before systemd attempts to mount.
> 
> While mdadm is still constructing the array (mdadm --incremental
> that is called from within
> /usr/lib/udev/rules.d/64-md-raid-assembly.rules), there is an attempt
> to mount the md device, but there is not a creation of
> "/run/mdadm/creating-xxx" file when in incremental mode that the rule
> is looking for.  Therefore the device is not marked as
> SYSTEMD_READY=0  in "/usr/lib/udev/rules.d/01-md-raid-creating.rules"
> and missing synchronization using the "/run/mdadm/creating-xxx" file.
> 
> Enable creating the "/run/mdadm/creating-xxx" file during
> incremental mode.

Hi Nigel,
The code is rather simple but the change is big. Before I will consider
it is safe to merge please describe the particular scenario you are
fixing.
It is known, persistent issue? Is is sporadic issue?

In the commit message please add why you think it is safe change.

This will affect every environment. We need to be certain that it will
not bring regression in booting flow. It might be hard to debug and
have big impact on users.

Thanks,
Mariusz

> 
> Signed-off-by: Nigel Croxon <ncroxon@redhat.com>
> ---
>   Incremental.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>