From: Keith Busch <kbusch@kernel.org>
To: Krishna Iyer <kiyer@crusoe.ai>
Cc: axboe@kernel.dk, hch@lst.de, sagi@grimberg.me,
linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
nilay@linux.ibm.com, hare@suse.de, saravanand@crusoe.ai,
sjpark@crusoe.ai, Hannes Reinecke <hare@kernel.org>
Subject: Re: [PATCH v5 1/2] nvme-multipath: fix path state evaluation for failfast and ANA
Date: Tue, 13 Oct 2026 09:36:46 -0600 [thread overview]
Message-ID: <as5QDrAp7srZgWwk@kbusch-mbp> (raw)
In-Reply-To: <20261008141407.22992-2-kiyer@crusoe.ai>
On Thu, Oct 08, 2026 at 07:14:06AM -0700, 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.
Thanks, applied to nvme-7.4.
next prev parent reply other threads:[~2026-10-13 15:36 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-08 14:14 [PATCH v5 0/2] nvme-multipath: fail I/O when no usable path exists Krishna Iyer
2026-10-08 14:14 ` [PATCH v5 1/2] nvme-multipath: fix path state evaluation for failfast and ANA Krishna Iyer
2026-10-13 14:29 ` Christoph Hellwig
2026-10-13 15:36 ` Keith Busch [this message]
2026-10-08 14:14 ` [PATCH v5 2/2] nvme-multipath: add fail_on_ctrl_loss sysfs attribute Krishna Iyer
2026-10-12 4:35 ` Nilay Shroff
2026-10-13 14:29 ` Christoph Hellwig
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