Host reconnecting need more than 60s to start after nvmetcli clear on target

[Christoph Hellwig]

On Tue, Sep 19, 2017 at 05:09:05PM +0800, Yi Zhang wrote:
> 
> 
> On 09/18/2017 11:58 PM, Christoph Hellwig wrote:
> > On Fri, Sep 08, 2017 at 07:44:37AM -0400, Yi Zhang wrote:
> > > Hi
> > > 
> > > I found this issue on latest 4.13, is it for designed?  I cannot reproduce it on 4.12.
> > > 
> > > Here is the log from host:
> > > 4.13
> > > [  637.246798] nvme nvme0: new ctrl: NQN "nqn.2014-08.org.nvmexpress.discovery", addr 172.31.0.90:4420
> > > [  637.436315] nvme nvme0: creating 40 I/O queues.
> > > [  637.939988] nvme nvme0: new ctrl: NQN "testnqn", addr 172.31.0.90:4420
> > > [  645.319803] nvme nvme0: rescanning
> > > 
> > > -->need more than 60 seconds to start reconnect
> > > 
> > > [  706.073551] nvme nvme0: Reconnecting in 10 seconds...
> > How did you initiate the reconnect?  Cable drop?
> 
> Just execute "nvmetcli clear" on target side, and check the log on host
> side.

Ok.  60 seconds is when the first commands will time out, so that's
expected.   The NVMeoF protocol has no way to notify the host that
a connection went away, so if you ren't on a protocol that supports
link up/down notifications we'll have to wait for timeouts.