Re: [PATCH 2/2] Manage: Inform udev about device removal when stopping

[Jes Sorensen <Jes.Sorensen@redhat.com>]

Sebastian Parschauer <sebastian.riemer@profitbricks.com> writes:
> When stopping an MD device, then its device node /dev/mdX may still
> exist afterwards or it is recreated by udev. The next open() call
> can lead to creation of an inoperable MD device. The reason for
> this is that a change event (KOBJ_CHANGE) is announced to udev.
> So announce a removal event (KOBJ_REMOVE) to udev instead.
>
> This also overrides the change event sent by the kernel.
>
> Signed-off-by: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
> ---
>  Manage.c |    6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/Manage.c b/Manage.c
> index 7e1b94b..bc89764 100644
> --- a/Manage.c
> +++ b/Manage.c
> @@ -494,13 +494,13 @@ done:
>  		goto out;
>  	}
>  	/* prior to 2.6.28, KOBJ_CHANGE was not sent when an md array
> -	 * was stopped, so We'll do it here just to be sure.  Drop any
> -	 * partitions as well...
> +	 * was stopped, it should be KOBJ_REMOVE instead, so we set the
> +	 * remove event here just to be sure. Drop any partitions as well...
>  	 */
>  	if (fd >= 0)
>  		ioctl(fd, BLKRRPART, 0);
>  	if (mdi)
> -		sysfs_uevent(mdi, "change");
> +		sysfs_uevent(mdi, "remove");

I am a little concerned about this change. You assume the kernel and
mdadm will be updated in sync, which is unlikely to happen. I believe
you need to match the kernel version and send the corresponding event
currectly for this to work correctly?

Jes