Re: [PATCH] /proc/scsi/map

Nick Bellinger
2002-06-22T19:23:33Z

On Sat, 2002-06-22 at 11:24, David Brownell wrote:
> > On the other hand there is the obvious fact that an iSCSI initiator
> > driver is not attached to a bus, and assuming /root/iSCSI.target/disk1
> > etc, is out of the question. There is a real need for a solution to
> > handle virtual devices (as stated your previous message) that are not
> > assoicated with any physical connectors.
>
> There are those who see the IP stack as a kind of logical bus ... :)
> It's just not tied any specific hardware interface; it's "multipathed" in
> some sense. Linking it to an eth0 entry in $DRIVERFS/root/pci0/00:10.0
> would be wrong, since it can also be accessed through eth2.
>
> Why shouldn't there be a $DRIVERFS/net/ipv4@10.42.135.99/... style hookup
> for iSCSI devices? Using whatever physical addressing the kernel uses
> there, which I assume wouldn't necessarily be restricted to ipv4. (And
> not exposing physical network topology -- routing! -- in driverfs.)
>
>
Giving the IP stack its own directory (leaf?) under driverfs root sounds
interesting enough and could have some potential uses, but in the case
of iSCSI there are a few problems:

iSCSI Names (aka: iSCSI Qualified Names or IEEE EUI-64 names ) are world
wide unique and are intended to stay with the iSCSI Node throughout its
lifetime, regardless of IP/HBA/NIC/etc changes. Also an iSCSI session
can include multiple TCP connections with each different IP addresses,
so the format of $DRIVERFS/net/ipv4@iSCSI.target.ip is insufficent.

This reiterates the need for a sound logical device naming scheme that
fits into driverfs without mucking up the basic structure. Not being a
expert on naming, the least offensive format I can think with regard to
iSCSI would be something along the lines of:

$DRIVERFS/virt/iscsi/iqn.2002-06.com.foo.super.turbo.disk.array.3543/disk0

being the iqn for an iSCSI Target node as viewed by an iSCSI Initiator
node.

Nicholas Bellinger