Bug#623613: Removing SAN mapping spawn uninterruptible process

[Laurent Bigonville]

Le Fri, 22 Apr 2011 04:29:51 +0530,
Ritesh Raj Sarraf <rrs at researchut.com> a écrit :

> On 04/22/2011 01:30 AM, Laurent Bigonville wrote:
> > When I'm removing a LUN mapping (association to the machine) using
> > the SAN manager, it seems that udev is starting several:
> >
> What is a SAN Manager here? An external tool?

Yes it is the IBM tool to manage the SAN

> Steps when unmapping a LUN is:
> * Ensure it has been freed from the initiator. (Includes FS, DM)
> * Unmap LUN on target
> * Rescan scsi bus on Initiator

umount && multipath -f lun_name
*unmap from san manager*
echo "- - -" >/sys/class/scsi_host/host*/scan

At that point multipath -ll does not show mapping anymore, but the
devices (/dev/sd*) are still present.

If I'm doing a multipath -r later, a new mpath0 appears and cannot be
removed (mpath0: map in use) due to uninteruptible process (kpartx and
blkid).

Doing echo 1 > /sys/block/sd*/device/delete as a last step (and before
issuing multipath -r) seems to fix the issue, so the problem here maybe
lies in udev which is not removing the nonexistent devices after a SCSI
rescan?

Cheers

Laurent Bigonville