https://bugzilla.kernel.org/show_bug.cgi?id=111441

--- Comment #13 from nab <nab@linux-iscsi.org> ---

On Mon, 2016-02-01 at 10:55 -0600, Mike Christie wrote:

On 01/30/2016 01:38 AM, Nicholas A. Bellinger wrote:

quoted

On Fri, 2016-01-29 at 17:32 -0600, Mike Christie wrote:

quoted

On 01/29/2016 04:21 PM, Serguei Bezverkhi (sbezverk) wrote:

quoted

HI Mike,

I tried your patch and it is has eliminated first traceback but I still do not see my remote targets.

That is sort of expected. Your target is not setup for ALUA properly. It
says it supports ALUA, but when scsi_dh_alua asks about the ports it is
reporting there are none. Ccing the people that made the patch that
added the issue and own the code.

Hey Christoph and Hannes,

The dh/alua changes that added this:

        error = scsi_dh_add_device(sdev);
        if (error) {
                sdev_printk(KERN_INFO, sdev,
                                "failed to add device handler: %d\n",
error);
                return error;
        }

to scsi_sysfs_add_sdev are adding a regression.

1. If that fails, then we forget to do device_del before doing the
return. My patch in this thread added that back, so we do not see the
sysfs oopses anymore. But.....

2. It looks like in older kernels, we would allow misconfigured targets
like this one to still setup devices. Do we want that old behavior back?
Should we just ignore the return value from scsi_dh_add_device above?
Note that in this case, it is LIO so it can be easily fixed on the
target side by just setting it up properly. I do not think other targets
would hit this type of issue.

Btw, what does misconfigured mean here wrt target ALUA..?

[   25.833195] sd 6:0:0:4: alua: supports implicit and explicit TPGS
[   25.833360] sd 6:0:0:4: alua: No target port descriptors found
[   25.833363] sd 6:0:0:4: alua: Attach failed (-22)
[   25.833365] sd 6:0:0:4: failed to add device handler: -22

Strange, this hasn't changed in forever on the target side..

He has LIO configured to report it supports implicit/explicit ALUA, but
the ports do not seem to be configured.

For the LIO config side, are his LUNs just not in a the default_lu_gp or
any other group?

So every non-PSCSI backend device becomes part of default_lu_gp +
default_tg_pt_gp and automatically shows up in EVPD=0x83, without user
needing to do any additional configuration.

Here's what the output looks like:

root@haakon3:/usr/src/target-pending.git# sg_inq -Hi /dev/sdb
VPD INQUIRY: Device Identification page
  <SNIP>
  Designation descriptor number 3, descriptor length: 8
    transport: Serial Attached SCSI Protocol (SPL-2)
    designator_type: Relative target port,  code_set: Binary
    associated with the target port
    designator header(hex): 61 94 00 04
    designator:
 00     00 00 00 02                                         ....
  Designation descriptor number 4, descriptor length: 8
    transport: Serial Attached SCSI Protocol (SPL-2)
    designator_type: Target port group,  code_set: Binary
    associated with the target port
    designator header(hex): 61 95 00 04
    designator:
 00     00 00 00 00                                         ....
  Designation descriptor number 5, descriptor length: 8
    designator_type: Logical unit group,  code_set: Binary
    associated with the addressed logical unit
    designator header(hex): 01 06 00 04
    designator:
 00     00 00 00 00                                         ....
 <SNIP>

So AFAICT, the relative target port, target port group, and logical unit
group being returned from target on v4.5-rc1 code looks correct.

Serguei, can you confirm with 'sg_inq -Hi /dev/sdX' output on your side
with the v3.10 based target..?

AFAICT the parsing in scsi_vpd_tpg_id() from commit a8aa3978 looks
correct too.

Hannes, any ideas..?

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