[openib-general] Problem with SRP with 512 byte sector size with > 2 TB LUNs

[Thomas Großmann]

Hello,

We have a disk-array connected over a Mellanox MT25204 IB
card. We have configured LUNs with a size of over 2 TB with
512 byte sector size and are using OpenIB 1.1 and SUSE SLES 10 x86_64. 
I get the following output in /var/log/messages when adding a LUN:

Feb  2 09:59:57 data1 kernel:   Vendor: DDN       Model: S2A 9550          
Rev: 3.03
Feb  2 09:59:57 data1 kernel:   Type:   Direct-Access                      
ANSI SCSI revision: 06
Feb  2 09:59:57 data1 kernel: sdc : very big device. try to use READ 
CAPACITY(16).
Feb  2 09:59:57 data1 kernel: sdc : READ CAPACITY(16) failed.
Feb  2 09:59:57 data1 kernel: sdc : status=0, message=00, host=5, driver=00
Feb  2 09:59:57 data1 kernel: sdc : use 0xffffffff as device size
Feb  2 09:59:57 data1 kernel: SCSI device sdc: 4294967296 512-byte hdwr 
sectors (2199023 MB)
Feb  2 09:59:57 data1 kernel: sdc: Write Protect is off
Feb  2 09:59:57 data1 kernel: sdc: Mode Sense: 97 00 10 08
Feb  2 09:59:57 data1 kernel: SCSI device sdc: drive cache: write back w/ FUA
Feb  2 09:59:57 data1 kernel: sdc : very big device. try to use READ 
CAPACITY(16).
Feb  2 09:59:57 data1 kernel: sdc : READ CAPACITY(16) failed.
Feb  2 09:59:57 data1 kernel: sdc : status=0, message=00, host=5, driver=00
Feb  2 09:59:57 data1 kernel: sdc : use 0xffffffff as device size
Feb  2 09:59:57 data1 kernel: SCSI device sdc: 4294967296 512-byte hdwr 
sectors (2199023 MB)
Feb  2 09:59:57 data1 kernel: sdc: Write Protect is off
Feb  2 09:59:57 data1 kernel: sdc: Mode Sense: 97 00 10 08
Feb  2 09:59:57 data1 kernel: SCSI device sdc: drive cache: write back w/ FUA
Feb  2 09:59:57 data1 kernel:  sdc: unknown partition table
Feb  2 09:59:57 data1 kernel: sd 8:0:0:0: Attached scsi disk sdc
Feb  2 09:59:57 data1 kernel: sd 8:0:0:0: Attached scsi generic sg2 type 0

I found in the Changelog of kernel 2.6.20 the following instruction:
target_host->max_cmd_len = sizeof ((struct srp_cmd *) (void *) 0L)->cdb;
(added to the function srp_create_target to achieve READ CAPACITY(16) )
and added it to the ib_srp module of OpenIB 1.1. 

The output was then:
Feb  5 17:53:07 data1 kernel:   Vendor: DDN       Model: S2A 9550          
Rev: 3.03
Feb  5 17:53:07 data1 kernel:   Type:   Direct-Access                      
ANSI SCSI revision: 06
Feb  5 17:53:07 data1 kernel: sdc : very big device. try to use READ 
CAPACITY(16).
Feb  5 17:53:07 data1 kernel: sdc : sector size 0 reported, assuming 512.
Feb  5 17:53:07 data1 kernel: SCSI device sdc: 1 512-byte hdwr sectors (0 MB)
Feb  5 17:53:07 data1 kernel: sdc: Write Protect is off
Feb  5 17:53:07 data1 kernel: sdc: Mode Sense: 97 00 10 08
Feb  5 17:53:07 data1 kernel: SCSI device sdc: drive cache: write back w/ FUA
Feb  5 17:53:07 data1 kernel: sdc : very big device. try to use READ 
CAPACITY(16).
Feb  5 17:53:07 data1 kernel: sdc : sector size 0 reported, assuming 512.
Feb  5 17:53:07 data1 kernel: SCSI device sdc: 1 512-byte hdwr sectors (0 MB)
Feb  5 17:53:07 data1 kernel: sdc: Write Protect is off
Feb  5 17:53:07 data1 kernel: sdc: Mode Sense: 97 00 10 08
Feb  5 17:53:07 data1 kernel: SCSI device sdc: drive cache: write back w/ FUA
Feb  5 17:53:07 data1 kernel:  sdc: unknown partition table
Feb  5 17:53:07 data1 kernel: sd 9:0:0:0: Attached scsi disk sdc
Feb  5 17:53:07 data1 kernel: sd 9:0:0:0: Attached scsi generic sg2 type 0

The same output was shown when trying to add a LUN using kernel 2.6.20.

Is it possible to add LUNs with > 2 TB and 512 byte sectors ?
Why does the READ CAPACITY(16) comand fail ?

Kind regards,
Thomas

-- 
 Thomas Großmann                
 High Performance Computing Center Stuttgart (HLRS)                                      
  
 Allmandring 30                                                
 70550 Stuttgart, Germany   

 E-Mail: grossmann at hlrs.de                                                              
 Phone: ++49-711-685-65529
 Fax  : ++49-711-685-65832