From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=mit.edu header.i=@mit.edu header.b="Q5sj5B3t" Received: from outgoing.mit.edu (outgoing-auth-1.mit.edu [18.9.28.11]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 41780D3 for ; Tue, 12 Dec 2023 07:18:43 -0800 (PST) Received: from cwcc.thunk.org (pool-173-48-124-235.bstnma.fios.verizon.net [173.48.124.235]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 3BCFGD14031942 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 12 Dec 2023 10:16:14 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mit.edu; s=outgoing; t=1702394176; bh=DtgEPyOZ4y0NfYNH2YIubU5zH6WNkZa4uw9X/YrTYR4=; h=Date:From:Subject:Message-ID:MIME-Version:Content-Type; b=Q5sj5B3tLr9igBweNwduA6PZT0jYBpf0QnbgLveixW6seItI++ZBFGLTSfMerXbHS p3Njc97PdcRGIf4TKVEIgxHBmronQjNXJXkrLeyzAbdW7GV1yA6oV2+VPV1gK1ydCA plr3+UqY8u6qAlN8rPtYydnRcIslVMIPw7x6+DKRYXPcipRYnF6o/Q/c+IcjyVQ1nz xX/twG+yBdGeDtIRnBvYz8ENuccCOYcaLXXX4fUlprrqCi9h59tRVipe7VYumU3kvK SwIQLaIYDR3Ok4/grND9PhvZx+JGOPReXUzLdYhTXSVb3FEptumR75NlyxpN2qeOgl 1tSRfCDMZ1iaQ== Received: by cwcc.thunk.org (Postfix, from userid 15806) id A517515C1422; Tue, 12 Dec 2023 10:16:13 -0500 (EST) Date: Tue, 12 Dec 2023 10:16:13 -0500 From: "Theodore Ts'o" To: Christoph Hellwig Cc: John Garry , Ojaswin Mujoo , linux-ext4@vger.kernel.org, Ritesh Harjani , linux-kernel@vger.kernel.org, "Darrick J . Wong" , linux-block@vger.kernel.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, dchinner@redhat.com Subject: Re: [RFC 0/7] ext4: Allocator changes for atomic write support with DIO Message-ID: <20231212151613.GA142380@mit.edu> References: <8c06c139-f994-442b-925e-e177ef2c5adb@oracle.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Dec 12, 2023 at 05:10:42AM -0800, Christoph Hellwig wrote: > On Tue, Dec 12, 2023 at 07:46:51AM +0000, John Garry wrote: > > It is assumed that the user will fallocate/dd the complete file before > > issuing atomic writes, and we will have extent alignment and length as > > required. > > I don't think that's a long time maintainable usage model. For databases that are trying to use this to significantly improve their performance by eliminating double writes, the allocation and writes are being done by a single process. So for *that* use case, it is quite maintainable. Cheers, - Ted