From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by mail19.linbit.com (LINBIT Mail Daemon) with ESMTP id C84C216094D for ; Fri, 13 Feb 2026 07:05:55 +0100 (CET) Date: Thu, 12 Feb 2026 22:05:54 -0800 From: Christoph Hellwig To: Christoph =?iso-8859-1?Q?B=F6hmwalder?= Subject: Re: [PATCH] drbd: always set BLK_FEAT_STABLE_WRITES Message-ID: References: <20260205173928.3166880-2-christoph.boehmwalder@linbit.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Cc: Jens Axboe , linux-block@vger.kernel.org, Philipp Reisner , linux-kernel@vger.kernel.org, Christoph Hellwig , Lars Ellenberg , drbd-dev@lists.linbit.com List-Id: "*Coordination* of development, patches, contributions -- *Questions* \(even to developers\) go to drbd-user, please." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, Feb 12, 2026 at 04:01:43PM +0100, Christoph Böhmwalder wrote: > The current block layer logic actually seems correct to me. The > underlying device may or may not require stable writes, but regardless > of that, DRBD itself definitely does need it. In blk_stack_limits, DRBD > is the top device, and DRBD's backing disk is the bottom device. If the > backing disk happens to require stable writes, this would indeed be > correctly inherited. > > So the only missing logic is that DRBD still wants to enable stable > writes for itself even if the backing disk does *not* request it. > So it seems to me that this patch is the correct fix for DRBD's special > case. > > Is it not supposed to work like that? No, I guess I just misunderstood your report.