Re: [PATCH v4 2/2] nvme-multipath: add fail_if_no_path sysfs attribute

From: Nilay Shroff

Date: Fri Oct 02 2026 - 07:53:30 EST


On 10/2/26 4:26 PM, Krishna Iyer wrote:
On 10/2/26 11:39 AM, Hannes Reinecke wrote:
I do get the problem, but I think that 'fail_if_no_path' is a misnomer.
Problem is that we already have a 'QUEUE_IF_NO_PATH' setting, so
'FAIL_IF_NO_PATH' really sounds like the inverstion of that.
Only that it isn't.
Maybe rename to 'FAIL_ON_CTRL_LOSS' to make it clear that the two
settings really describe different use-cases?

Agreed, and thanks. You are right that fail_if_no_path reads as the
inverse of queue_if_no_path when it is not, and the v4 split makes that
clearer. Patch 1 now fails the cases where a path exists but cannot
serve I/O, so the only thing this attribute still does is stop waiting
for a controller that is gone or reconnecting. I am happy to rename it,
and fail_on_ctrl_loss describes that well.

One piece of history worth surfacing first. The fail_if_no_path name was
Nilay's suggestion in v2, so I would request we settle on one name you
both agree on rather than change it twice. Nilay, does fail_on_ctrl_loss
work for you?
Yes, I also like fail_on_ctrl_loss as Hannes suggested.

The earlier fail_if_no_path name came from the dm-multipath policy, which
uses the same name for a similar use case. However, I agree that fail_if_no_path
could be misleading here since it sounds like the inverse of QUEUE_IF_NO_PATH.

So I'd vote for fail_on_ctrl_loss for this change.

Thanks,
--Nilay