DLPX-71852 iSCSI: journal flooded with "Unable to locate Target IQN" messages

[pzakha]

This disables this kind of messages that flood the logs when an iscsi initiator tries to access an iscsi target that doesn't exist on the server:

kernel: [741363.397732] Unable to locate Target IQN: iqn.2008-07.com.delphix:02:44739d0c-a359-6ad9-a11e-f7d9bc1f7b32 in Storage Node
kernel: [741363.401405] iSCSI Login negotiation failed.

This is usually the result of an iscsi initiator that was previously configured with a different server with the same IP, or with the same server that underwent factory reset.

PRs for other flavors

delphix/linux-kernel-aws#2
delphix/linux-kernel-azure#2
delphix/linux-kernel-gcp#2
delphix/linux-kernel-oracle#2

Testing

• ab-pre-push: http://selfservice.jenkins.delphix.com/job/devops-gate/job/master/job/appliance-build-orchestrator-pre-push/4700
• Tested by adding an iscsi initiator to the DE (from Delphix's perspective, a "Windows Target Environment"), then running developer reset on the DE. Messages don't appear in the logs anymore, but can be re-enabled dynamically by running:

  sudo bash -c "echo 'file iscsi_target_login.c line 1180 +p' > /sys/kernel/debug/dynamic_debug/control"
  sudo bash -c "echo 'file iscsi_target_nego.c line 1169 +p' > /sys/kernel/debug/dynamic_debug/control"