From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 97AE5C9830D for ; Wed, 23 Sep 2026 21:48:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=vw5qY40x4C5dklJ73ibDmRnrR0RKgmbPRP29+0wyXUg=; b=hYW+mPMA/Kue/MephYhNZx7yVW 64eO/OzCvnvN8+yL3SecnWjyU/m4zOXOQ/yinAvz/xxYYUUhvvCwKcQpgBE8zcacixXhny3vReCg7 BB3KGWBZRM88o6EartbrQTIUaB1lccVysgOrbdh6jHUj/TPVCvahTBByFpkc9uXX624CkuOuVcd9E KnQUzDJhWpaueju+w06qWEsNaKrE5qAUANhtWit4irEEicBup5lnVY1oa9U0iGcLceKv2o16AAbXk nK9NRPzO08K9gu1EwlC5NV1NSx9uuT6h72RlVfI2+eQsjEWIsgC73W9RouGSH9NVMdyIBwNdIJSC4 taewRuAQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x9UpL-00000009c27-2IYQ; Wed, 23 Sep 2026 21:48:31 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x9UpL-00000009c21-0ByV for linux-nvme@lists.infradead.org; Wed, 23 Sep 2026 21:48:31 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 7890743B49; Wed, 23 Sep 2026 21:48:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0937F1F000FF; Wed, 23 Sep 2026 21:48:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790200110; bh=vw5qY40x4C5dklJ73ibDmRnrR0RKgmbPRP29+0wyXUg=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=h6QBh8V05EqLJ+IYPefzsG2aoVf20/NeCh93Ws9r49BOCWzkn14nEUc9cAcyIo+lh lvIMgxuk+dkuKDQ3rN1eMjpY9Kna0PPlKpk/uvUjWzQICRxCiVB9TisW+MfOyeXJH0 swGOl12LFGg709dPQgXRkV8lCxBEo9KqLUIyWiJwTBnZfskAAwkOCaaTvwTC9scJna 6VvDGwSBOwdNyrQHzR71sugKEqYyDK5dFbYEKYKPDmLtXq8L+0sSwOKA0iSK230s53 9/NBx8K1n9h37RahvbnBvnL5eZ3VyjjPyS30hAeOGLGbxj6R+JOttU7cAvgks5cIQt 2T26f8YL5xKcw== Date: Wed, 23 Sep 2026 15:48:28 -0600 From: Keith Busch To: Krishna Iyer Cc: axboe@kernel.dk, hch@lst.de, sagi@grimberg.me, linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, nilay@linux.ibm.com, sjpark@crusoe.ai, saravanand@crusoe.ai Subject: Re: [PATCH v3] nvme-multipath: add fail_if_no_path sysfs attribute Message-ID: References: <20260923004959.88440-1-kiyer@crusoe.ai> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260923004959.88440-1-kiyer@crusoe.ai> X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Tue, Sep 22, 2026 at 05:49:59PM -0700, Krishna Iyer wrote: > When no usable path exists, I/O on a multipath namespace is queued > until a path returns. With ctrl_loss_tmo=-1 that can be forever: > during a long fabric outage any process waiting on the I/O is stuck in > D state. We hit this on virtualization hosts, where a SIGKILLed VM > process cannot exit while draining I/O to an unreachable NVMe/TCP > target. > > Nothing can fail this I/O without tearing something down: controller > deletion takes every namespace on the controller with it. I agree with Hannes that we shouldn't need a new flag for this. The current behavior is just broken in a few ways. We just need to restrict queue_if_no_path to only if there really are no paths so that we actually respect the failfast_tmo. And the ANA inaccessible and persistent-loss handling you introduced here should just be the default without requiring a flag. But I think you need to add a requeue_list kick in nvme_update_ns_ana_state() too in case the ANA transition leaves the namespace inaccessible.