[PATCH v4 1/2] nvme-multipath: fix path state evaluation for failfast and ANA

[Nilay Shroff]

On 10/1/26 3:18 PM, Krishna Iyer wrote:
> nvme_available_path() has two problems that keep I/O queued when it
> should be failed:
> 
> 1. When fast_io_fail_tmo expires, NVME_CTRL_FAILFAST_EXPIRED is set and
>     the path is skipped, but the function still falls through to
>     nvme_mpath_queue_if_no_path(). If delayed_removal_secs is configured
>     the I/O is requeued indefinitely, defeating fast_io_fail_tmo. Only
>     fall through to queue_if_no_path when there really are no paths;
>     if a path exists but its failfast timer has expired, fail instead.
> 
> 2. A LIVE controller counts as a usable path regardless of the namespace
>     ANA state. A path whose ANA state is inaccessible or persistent-loss
>     cannot serve I/O, so it should not count as available. ANA change is
>     transient and bounded by ANATT, so keep queueing while it resolves.
> 
> Also kick the requeue work from nvme_update_ns_ana_state() when a path
> does not transition to live, so parked I/O is re-evaluated when an ANA
> transition leaves the namespace inaccessible.
> 
> Move nvme_state_is_live() above nvme_available_path() so it can be used
> there.
> 
> Assisted-by: Claude:claude-fable-5
> Signed-off-by: Krishna Iyer<kiyer at crusoe.ai>

Looks good to me.
Reviewed-by: Nilay Shroff <nilay at linux.ibm.com>