targetcli/LIO needs tcm_vhost and xen-scsiback feature enabled OR option disabled

I have flagged this as affecting:

- targetcli-fb (vhost feature broken)

- QEMU (vhost scsi support enabled ?)

- kernel (would need TCM_VHOST feature enabled)

Please other teams/people,

let me know your thoughts. I'm able to disable those existing fabric LIO modules, but... at least TCM VHOST might be worth to be kept (if we can explore/enable in QEMU).

Cheers

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1891214

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

Hi Rafael,

on the qemu side I think we are ready,
we have
  CONFIG_VHOST_USER=y CONFIG_VHOST_KERNEL=y
already and also virtio-scsi already enabled.
  vhost-net support yes
  vhost-crypto support yes
  vhost-scsi support yes
  vhost-vsock support yes
  vhost-user support yes
  vhost-user-fs support yes

I think we are good with that as-is.

If you happen to find anything you need changed in qmeu let me know, but until then I'll keep this as incomplete.

Okay, since TCM_VHOST is experimental in kernel, as we are in feature freeze for Groovy, I'm going to cap the missing features from targetcli so end user does not experience failures from the UI. This bug can serve as a future guidance in enabling those options (specially TCM_VHOST).

Ooops TCM_VHOST is good for Groovy:

/> cd /vhost
/vhost> create
Created target naa.500140533cd76f07.
Created TPG 1.

/vhost> delete naa.500140533cd76f07
Deleted Target naa.500140533cd76f07.

/vhost> quit

Tagging linux as Fix Released.

$ sudo modinfo tcm_vhost
filename: /lib/modules/5.8.0-18-generic/kernel/drivers/vhost/vhost_scsi.ko
license: GPL
alias: tcm_vhost
description: VHOST_SCSI series fabric driver
srcversion: 2AD428CAF926D0F5A58751D
depends: target_core_mod,vhost
retpoline: Y
intree: Y
name: vhost_scsi
vermagic: 5.8.0-18-generic SMP mod_unload
sig_id: PKCS#7
signer: Build time autogenerated kernel key
sig_key: 36:2A:15:BD:BF:65:C1:25:91:5F:A9:27:E5:4C:76:B8:C2:26:6B:1C
sig_hashalgo: sha512
signature: 65:8B:63:37:F0:CE:40:48:AF:56:65:DC:F3:6F:29:DB:E8:D9:A7:86:

/vhost> cd /xen-pvscsi
l/xen-pvscsi> ls
o- xen-pvscsi .......................................................................... [Targets: 0]
/xen-pvscsi> create
b"modprobe: ERROR: could not insert 'xen_scsiback': No such device\n"
/xen-pvscsi> quit

Will disable the XEN-PVSCSI then.

## XEN PVSCSI

Same happens for XEN:

https://wiki.xenproject.org/wiki/Paravirtualized_SCSI

With suggested fix:

[rafaeldtinoco@guestdevel ubuntu]$ sudo targetcli
targetcli shell version 2.1.53
Copyright 2011-2013 by Datera, Inc and others.
For help on commands, type 'help'.

/> ls /
o- / .......................................................................................... [...]
  o- backstores ............................................................................... [...]
  | o- block ................................................................... [Storage Objects: 0]
  | o- fileio .................................................................. [Storage Objects: 0]
  | o- pscsi ................................................................... [Storage Objects: 0]
  | o- ramdisk ................................................................. [Storage Objects: 0]
  o- iscsi ............................................................................. [Targets: 0]
  o- loopback .......................................................................... [Targets: 0]
  o- vhost ............................................................................. [Targets: 0]
/> cd /xen-pvscsi
No such path /xen-pvscsi

This bug was fixed in the package python-rtslib-fb - 2.1.73-1ubuntu4

---------------
python-rtslib-fb (2.1.73-1ubuntu4) groovy; urgency=medium

  * Disable xen-pvscsi due to unsup xen_scsiback module (LP: #1891214)

 -- Rafael David Tinoco <email address hidden> Tue, 08 Sep 2020 17:11:00 +0000