Commands fail on nvme-cli 2.x when nvme_core module isn't loaded, regression from nvme-cli 1.x

[Caleb Sander]

On nvme-cli 1.x, nvme list, nvme disconnect-all, etc. are no-ops when the nvme_core module isn't loaded:

[root@init100-17-1 ~]# lsmod | grep nvme
[root@init100-17-1 ~]# nvme version
nvme version 1.16
[root@init100-17-1 ~]# nvme list
Node                  SN                   Model                                    Namespace Usage                      Format           FW Rev
--------------------- -------------------- ---------------------------------------- --------- -------------------------- ---------------- --------
[root@init100-17-1 ~]# nvme disconnect-all

But on nvme-cli 2.x, they fail when trying to open the nonexistent /sys/class/nvme. It would be nice for the commands to be no-ops again.

[root@init100-17 ~]# lsmod | grep nvme
[root@init100-17 ~]# nvme version
nvme version 2.2.1 (git 2.2.1)
libnvme version 1.2 (git 1.2)
[root@init100-17 ~]# nvme list
Failed to scan topology: No such file or directory
[root@init100-17 ~]# nvme disconnect-all
Failed to scan topology: No such file or directory

[Daniel Wagner]

Is still the case with v2.8? I thought it should not complain anymore.

[Caleb Sander]

Yes, I just tried it with 2.8:

[root@init100-17 nvme-cli]# nvme version
nvme version 2.8 (git 2.8-38-g2af3218)
libnvme version 1.8 (git 1.8-22-gd96e92a)
[root@init100-17 nvme-cli]# modprobe -r nvme_core
[root@init100-17 nvme-cli]# nvme disconnect-all
Failed to scan topology: No such file or directory