Re: SCSI Patches - mostly on/off-line stuff

[Oliver Neukum <Oliver.Neukum@lrz.uni-muenchen.de>]

> > devfsd is at least already here. The existing /sbin/hotplug architecture
> > can't handle it. A new kind of event would be needed.
>
> A new event type doesn't change the architecture ... if
> that's all that's needed, the architecture is unchanged!

Ok, so we don't call an extension a change ;-)

But the required changes to other subsystems would be
larger. You'd need to call the helper at

- SCSI bus scanning
- Partition detection
- disk change detection
- module insertation/removal

at least. Possibly at other places too.
And you'd begin to get some issues, like
disk change -> helper script -> open device file -> disk change -> helper 
script -> etc ...

This is starting to get messy, IMHO.
I am not sure whether you can run these scripts in paralel.
And by the way some of this is needed for scsi<->usb bridges.

> To some folk, it won't even matter if the event comes from
> a devfsd thread or a kernel thread.  Implementation detail.
> Except maybe to the US Patent Office ... sigh.  (One
> iteration of USB hotplugging did just that:  devfsd called
> the same policy scripts as the kernel thread version.)

Devfs can give you a name to work on.
The kernel thread'll give you major/minor at best.
But that's a small difference.

> > Even so, you'll probably won't make the user happy if it works only
> > on plugging in and not when he puts in a new medium.
> > A look at supermount might be in order.
>
> Yep, lots of tools to choose from.  But again, not everyone
> runs supermount (or wants to) -- Yet Another Daemon, as I
> recall the situation.

It's a proper filesystem without a demon.
Why would a requirement to use a filesystem to enjoy a feature
be unreasonable ? If you can require usbdevfs you can require
supermount, too, IMHO.

	Regards
		Oliver

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