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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id E8668C43334 for ; Tue, 5 Jul 2022 16:11:40 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4F8796B0071; Tue, 5 Jul 2022 12:11:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4A9126B0073; Tue, 5 Jul 2022 12:11:40 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 396846B0074; Tue, 5 Jul 2022 12:11:40 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 2D2966B0071 for ; Tue, 5 Jul 2022 12:11:40 -0400 (EDT) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 00F5E60962 for ; Tue, 5 Jul 2022 16:11:39 +0000 (UTC) X-FDA: 79653536760.03.B7B39B7 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf24.hostedemail.com (Postfix) with ESMTP id CB475180059 for ; Tue, 5 Jul 2022 16:11:37 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id D46A367373; Tue, 5 Jul 2022 18:11:32 +0200 (CEST) Date: Tue, 5 Jul 2022 18:11:32 +0200 From: Christoph Hellwig To: Josef Bacik Cc: Jens Axboe , "Darrick J. Wong" , Al Viro , Stefan Roesch , io-uring@vger.kernel.org, kernel-team@fb.com, linux-mm@kvack.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, david@fromorbit.com, jack@suse.cz, hch@infradead.org, Christoph Hellwig , rgoldwyn@suse.com Subject: Re: [PATCH v7 15/15] xfs: Add async buffered write support Message-ID: <20220705161132.GA13721@lst.de> References: <20220601210141.3773402-1-shr@fb.com> <20220601210141.3773402-16-shr@fb.com> <0a75a0c4-e2e5-b403-27bc-e43872fecdc1@kernel.dk> <47dd9e6a-4e08-e562-12ff-5450fc42da77@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1657037499; a=rsa-sha256; cv=none; b=CPOWsIsJ1oVT8bI6fLkd3SV9sArmWjh3asYxC/mLycg9BesFb3ZUk2c0HLCaHNzz/9LHC4 k/DHfJOzvuFxqHXxoBBl3wN0g52C/KXCnlrq+BnQE/3mtJRrOnoShf4CNYNLz+FEsdJmUi idqKt73ov4z1Zf241zrNkMX935NWvow= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=none; dmarc=none; spf=none (imf24.hostedemail.com: domain of hch@lst.de has no SPF policy when checking 213.95.11.211) smtp.mailfrom=hch@lst.de ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1657037499; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ijl5A+Au86K2bGZ2veMcDPh9Q9UmLuSNii4P+K26Mq4=; b=y3XHGPxeKxveCSS7aN8ggsUvhH6n8WcG9aKeOk7kttAq4b6aXeL1t8n/TLk1wT+yAVEUo6 Qte8PgpT7abi/kdIo17uSlr8+hUgkAOfB/HA09/6UE1vSS/7Xeogt2LCkoj5G9ntdTyaq6 zoZpZJyT+PxXhwMILHbjI/3SCdjbzNc= Authentication-Results: imf24.hostedemail.com; dkim=none; dmarc=none; spf=none (imf24.hostedemail.com: domain of hch@lst.de has no SPF policy when checking 213.95.11.211) smtp.mailfrom=hch@lst.de X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: CB475180059 X-Rspam-User: X-Stat-Signature: yfx76jm9stwhnp4ab3xjr7myortbmrjs X-HE-Tag: 1657037497-449618 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Jul 05, 2022 at 09:47:25AM -0400, Josef Bacik wrote: > This appears to be just a confusion about what we think NOWAIT should mean. > Looking at the btrfs code it seems like Goldwyn took it as literally as possible > so we wouldn't do any NOWAIT IO's unless it was into a NOCOW area, meaning we > literally wouldn't do anything other than wrap the bio up and fire it off. It means don't do anything that would block. And I suspect in btrfs the above is about as much as you can do without blocking.