Received: by 2002:a25:ef43:0:0:0:0:0 with SMTP id w3csp192866ybm; Thu, 28 May 2020 20:17:42 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwbm3kCiGNIKA/Ev1fVExHFha6mecnJgcWPyyNhnff5EpUZ/ElEWsIUVUY/vLg4SjmUQgv+ X-Received: by 2002:a50:fb1a:: with SMTP id d26mr6280327edq.83.1590722261868; Thu, 28 May 2020 20:17:41 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1590722261; cv=none; d=google.com; s=arc-20160816; b=Ogg4yiEKsAiHw/hxK1URTxpnYTOrxDNQL+/wg2XbssXT/ZUfC+qKL2vGU+W/afL3QJ gcWct/Y/E6IMdbBFtYHlbcFdp/4kjORJoceHful0OoP2PrNQq5a4KqN/1/TNn0RXeLvq 63N2QZ0mfOpBuDbkeD6AyZS+8cM6dXmwEe4BqQRirUZhG16zaujzx1P0+6ksmTZ2vHNn FcxcPCUHKSJaMb1MJIHRtKJec56zm3yXx7R1PEp0A07r9Bql3LcftLyIOYbOOviajkn2 bZ/4lWNcDXSgnaKnYMDnVdy4QJyEpc9onpIfANJ5a0hWnSDFYf83F+ZOUS0MapdKlT5i e0Zw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:in-reply-to:content-disposition :mime-version:references:message-id:subject:cc:to:from:date; bh=cDqD6CFPAUhZ94kTOaDo0ufedjpnz6A3Q0cdmStGjQc=; b=btoZgL9kY6NtIQqjheBXQaOLyWrTtr76M15ioEsryvhEwcTd12gGQhzUURl8gf75h/ rXJyeAYGBn7q8zRQBnSDJ4wlxEVtZz5nH7QSiXd+lcsdR2Ukkdu1cjfimiacrJijbMzZ GoVQUE5gcketUPUQLv+p0Zd0+8EJcoLywpZxQOhWBon3Ceih7YrjJA/VbsICd1of+1WW yQR65NikHE2Bc7p4HnXmXpBp47VHA+EtWXL0i+ngentB8gg1NAfViaWAii/1SVQT1T+v uV7AOYZvt/b+YpUXTkxhMg55it5n9vlPsmMf8pe7d0sud7rIYmiTGhvBZi2RGjVds5Ui oXYg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-ext4-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id gg10si4257153ejb.413.2020.05.28.20.17.17; Thu, 28 May 2020 20:17:41 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-ext4-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391677AbgE2DPG (ORCPT + 99 others); Thu, 28 May 2020 23:15:06 -0400 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:55520 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2390190AbgE2DPE (ORCPT ); Thu, 28 May 2020 23:15:04 -0400 Received: from callcc.thunk.org (pool-100-0-195-244.bstnma.fios.verizon.net [100.0.195.244]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 04T3F0WA026372 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 28 May 2020 23:15:01 -0400 Received: by callcc.thunk.org (Postfix, from userid 15806) id 810BA420304; Thu, 28 May 2020 23:15:00 -0400 (EDT) Date: Thu, 28 May 2020 23:15:00 -0400 From: "Theodore Y. Ts'o" To: Jens Axboe Cc: linux-ext4@vger.kernel.org Subject: Re: [PATCH] ext4: don't block for O_DIRECT if IOCB_NOWAIT is set Message-ID: <20200529031500.GK228632@mit.edu> References: <76152096-2bbb-7682-8fce-4cb498bcd909@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <76152096-2bbb-7682-8fce-4cb498bcd909@kernel.dk> Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Sun, May 24, 2020 at 04:53:16PM -0600, Jens Axboe wrote: > Running with some debug patches to detect illegal blocking triggered the > extend/unaligned condition in ext4. If ext4 needs to extend the file (and > hence go to buffered IO), or if the app is doing unaligned IO, then ext4 > asks the iomap code to wait for IO completion. If the caller asked for > no-wait semantics by setting IOCB_NOWAIT, then ext4 should return -EAGAIN > instead. > > Signed-off-by: Jens Axboe Thanks, applied. - Ted