From mboxrd@z Thu Jan 1 00:00:00 1970 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.subspace.kernel.org (Postfix) with ESMTPS id AB1C41494AC; Thu, 23 May 2024 12:59:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716469185; cv=none; b=qtPj7v5qbkk4CPVOdkzuj/BCzx+LXeBPnpLsP7AWQSCud6oFsWc55hejiLu/WD/OcvKjOj6oNb4cuwQATzfOrB7zoxnf9DGCqVh5hZUPFtnWngq9EmWIW+E6tD3l9KC0J9MI9UVzhdjUcivYvkZ1tFf3h8W745oSG4ztX1o3T4s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716469185; c=relaxed/simple; bh=r/jKk9ccksY/9WiNmL6OIFw97z+/dtosx4ERQ9Umakw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=QMEtkAcvkmur1yR+49uKYOtMJwgklfgQirFdi3nLh883dW32XvYK/ocqIyfNuaMBCytNpOQjYedSss/arPJX0m0BWQm/8fbXslgZgckkGqY+DG3JVAUI2Y6fYvO/ot5Ou10XjfxKNRLhHObAiSmsdj2gT4qlDSiUZ7n5M0NNJXs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=KDndgTDg; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="KDndgTDg" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=iDDVfg/vJO5TvVPe2vKaGxm0sb/5qDyjmp6tSkeBIJY=; b=KDndgTDg2qikMCFERZR+gFarmK 9G/Uj8HEob9i/zOZ/rQiZOw+8Sls3K+AIZqyY7HhAGmtHePMnCx78hTbnK8Iq3OyAhYH6ARHTBLt6 wR5IXYGJvkh7bcWGCIe+KXZkcWisgmyslwcHVE6IG0EfdIuSFBrcGyEARAZxPg+5aJ7sUx8l6482D +hcu1V7NJ8kMFKU0wlgbCUfHNH8Vbmem8ep65CqepoNeUcl5YEB0V75Vmino4e9KfjPwgnywW6XIl AeO4ytyHtrUjUCebIU6hlTDJIN9baFTVLKwInT2vNigDOIlHjHF5Xadzj3VzqYMmEOWg/Rq49enPS Ugz/Y4yQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1sA82m-00000006IH1-1BCC; Thu, 23 May 2024 12:59:40 +0000 Date: Thu, 23 May 2024 05:59:40 -0700 From: Christoph Hellwig To: John Garry Cc: Theodore Ts'o , lsf-pc@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-mm , Luis Chamberlain , "Martin K. Petersen" , Matthew Wilcox , Dave Chinner , linux-kernel@vger.kernel.org Subject: Re: [LSF/MM/BPF TOPIC] untorn buffered writes Message-ID: References: <20240228061257.GA106651@mit.edu> <9e230104-4fb8-44f1-ae5a-a940f69b8d45@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: <9e230104-4fb8-44f1-ae5a-a940f69b8d45@oracle.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Wed, May 15, 2024 at 01:54:39PM -0600, John Garry wrote: > On 27/02/2024 23:12, Theodore Ts'o wrote: > > Last year, I talked about an interest to provide database such as > > MySQL with the ability to issue writes that would not be torn as they > > write 16k database pages[1]. > > > > [1] https://urldefense.com/v3/__https://lwn.net/Articles/932900/__;!!ACWV5N9M2RV99hQ!Ij_ZeSZrJ4uPL94Im73udLMjqpkcZwHmuNnznogL68ehu6TDTXqbMsC4xLUqh18hq2Ib77p1D8_4mV5Q$ > > > > After discussing this topic earlier this week, I would like to know if there > are still objections or concerns with the untorn-writes userspace API > proposed in https://lore.kernel.org/linux-block/20240326133813.3224593-1-john.g.garry@oracle.com/ > > I feel that the series for supporting direct-IO only, above, is stuck > because of this topic of buffered IO. Just my 2 cents, but I think supporting untorn I/O for buffered I/O is an amazingly bad idea that opens up a whole can of worms in terms of potential failure paths while not actually having a convincing use case. For buffered I/O something like the atomic msync proposal makes a lot more sense, because it actually provides a useful API for non-trivial transactions.