Re: [PATCH blktests v3] nvme/046: test queue count changes on reconnect

[Daniel Wagner <dwagner@suse.de>]

On Tue, Sep 13, 2022 at 07:10:49PM +0200, Daniel Wagner wrote:
> On Tue, Sep 13, 2022 at 01:42:11PM +0200, Daniel Wagner wrote:
> > On Tue, Sep 13, 2022 at 10:57:44AM +0000, Shinichiro Kawasaki wrote:
> > > FYI, each blktests test case can define DMESG_FILTER not to fail with specific
> > > keywords in dmesg. Test cases meta/011 and block/028 are reference use
> > > cases.
> > 
> > Ah okay, let me look into it.
> 
> So I made the state read function a bit more robust (test if state file
> exists) and the it turns out this made rdma happy(??) but tcp is still
> breaking.

s/tcp/fc/

On closer inspection I see following sequence for fc:

[399664.863585] nvmet: connect request for invalid subsystem blktests-subsystem-1!
[399664.863704] nvme nvme0: Connect Invalid Data Parameter, subsysnqn "blktests-subsystem-1"
[399664.863758] nvme nvme0: NVME-FC{0}: reset: Reconnect attempt failed (16770)
[399664.863784] nvme nvme0: NVME-FC{0}: reconnect failure
[399664.863837] nvme nvme0: Removing ctrl: NQN "blktests-subsystem-1"

When the host tries to reconnect to a non existing controller (the test
called _remove_nvmet_subsystem_from_port()) the target returns 0x4182
(NVME_SC_DNR|NVME_SC_READ_ONLY(?)). So arguably fc behaves correct by
stopping the reconnects. tcp and rdma just ignore the DNR.

If we agree that the fc behavior is the right one, then the nvmet code
needs to be changed so that when the qid_max attribute changes it forces
a reconnect. The trick with calling _remove_nvmet_subsystem_from_port()
to force a reconnect is not working. And tcp/rdma needs to honor the
DNR.

Daniel