Re: [PATCH] REPORT LUN scan even if no storage is available on LUN 0

[Patrick Mansfield <patmans@us.ibm.com>]

On Fri, Jan 14, 2005 at 02:26:23PM +0100, Guido Guenther wrote:
> On Thu, Jan 13, 2005 at 04:21:34PM -0800, Patrick Mansfield wrote:

> This is the target that has all the devices:
> # echo "0 0 -" > /sys/class/scsi_host/host0/scan
> scsi_scan_host_selected: <0:0:0:4294967295>
> scsi scan: INQUIRY to host 0 channel 0 id 0 lun 0
> scsi <0:0:0:0> send                  scsi0 : destination target 0, lun 0
>         command = Inquiry 00 00 00 24 00
> scsi <0:0:0:0> done SUCCESS        0 scsi0 : destination target 0, lun 0
>         command = Inquiry 00 00 00 24 00
> scsi scan: 1st INQUIRY successful with code 0x0
> scsi <0:0:0:0> send                  scsi0 : destination target 0, lun 0
>         command = Inquiry 00 00 00 95 00
> scsi <0:0:0:0> done SUCCESS        0 scsi0 : destination target 0, lun 0
>         command = Inquiry 00 00 00 95 00
> scsi scan: 2nd INQUIRY successful with code 0x0
> scsi scan: peripheral qualifier of 3, no device added
> scsi scan: Sequential scan of host 0 channel 0 id 0
> 
> While this is an empty one:
> # echo "0 1 -" > /sys/class/scsi_host/host0/scan
> scsi_scan_host_selected: <0:0:1:4294967295>
> scsi scan: INQUIRY to host 0 channel 0 id 1 lun 0
> scsi <0:0:1:0> send                  scsi0 : destination target 1, lun 0
>         command = Inquiry 00 00 00 24 00
> scsi <0:0:1:0> done SUCCESS    10000 scsi0 : destination target 1, lun 0
>         command = Inquiry 00 00 00 24 00
> scsi scan: 1st INQUIRY failed with code 0x10000

Your device must be reporting as SCSI-2, that makes sense, since you
needed other bflags set. The logging should really dump the scsi_level.
You need to add an entry to the devinfo list to force a REPORT LUNs scan.

I don't know why it is not already in scsi_devinfo.c, AFAIR REPORT LUNs
has always worked with EMC, and should be in its devinfo flag (and
probably the only devinfo flag, since sparse, largelun and forcelun are
meaningless for a REPORT LUN scan).

module params can be used, but /proc/scsi/device_info is easiest. Make
sure I have the correct vendor:model, this should work:

	echo "EMC:SYMMETRIX:0x20000" > /proc/scsi/device_info

BLIST_REPORTLUN2 is 0x20000.

-- Patrick Mansfield