Re: [PATCH 2/2] Drivers: scsi: storvsc: Force discovery of LUNs that may have been removed.

From: James Bottomley
Date: Fri Aug 29 2014 - 09:53:57 EST

On Fri, 2014-08-29 at 10:13 +0200, Hannes Reinecke wrote:
> On 08/29/2014 09:39 AM, Bart Van Assche wrote:
> > On 08/29/14 08:19, Hannes Reinecke wrote:
> >> On 08/29/2014 04:42 AM, Mike Christie wrote:
> >>> How are distros handling 0x6/0x3f/0x0e (report luns changed) when it
> >>> gets passed to userspace? Is everyone kicking off a new full (add and
> >>> delete) scan to handle this or logging it? Is the driver returning this
> >>> when the LUNs change?
> >>>
> >> Currently it's logged to userspace and ignored.
> >> Doing an automated rescan has proven to be dangerous, as it
> >> might disconnect any LUNs which are still in use by applications.
> >> Especially HA or database setups tends to become very annoyed
> >> when you do an automated rescan.
> >
> > Has it already been considered to add newly discovered LUNs
> > automatically and to leave it to the user to remove stale LUNs manually
> > ? That would be similar to what the script does
> > without option -r/--remove.
> >
> As of now we're still missing an in-kernel infrastructure which
> would allow us to react on any sense codes; currently we're relying
> on the administrator to setup a udev rule here.

Um, I thought this was supposed to solve that problem:

commit 279afdfe78a020b4b1a68bffd0009b961b12982e
Author: Ewan D. Milne <emilne@xxxxxxxxxx>
Date: Thu Aug 8 15:07:48 2013 -0400

[SCSI] Generate uevents on certain unit attention codes

The idea was supposed to be that, as you say, log scrubbers are hard to
configure and break every time someone fixes a spelling error, so we
could now listen for a report luns data change uevent instead.