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 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.lore.kernel.org (Postfix) with ESMTPS id C5359C0218D for ; Fri, 31 Jan 2025 07:07:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=BuNkhA4U2EXzY3UIav9rX8ABnEiVHzXbjByWKZyeJio=; b=TeVAn789EDElSKEXGMOp1ZaqRL Ua5V++1k89e11Kfu88iSkxtyxfgVm1YrioSc/5tBz9UANPZvLCHr1tnAwoZea8DDrVXgAZLM0SkO8 1MSbJ6xHdaNL/OmMv4ZBzxfePHbKdGFghHWaFvqKX5xM4uyTcrkM+UgjOaN+KmvHymPKS65mnNEkV WPE/F3bt6+FdNvZK9TjkY1T6NUwfMTHRlWaVEI/lNoaWYePDuQxPJcbEnDW2QIHw6IXRPVzDQBIGy gBes7oTKyH9fTOPVNgA1n8T4ktkSjtA7O1xlyO1PeZ6XUOpjQK93Cskm5aJgmRzEg0YBn0Xlxtcqn iTfgjPdw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tdl80-0000000A5JH-45ww; Fri, 31 Jan 2025 07:07:48 +0000 Received: from hch by bombadil.infradead.org with local (Exim 4.98 #2 (Red Hat Linux)) id 1tdl7w-0000000A5J4-1JuT; Fri, 31 Jan 2025 07:07:44 +0000 Date: Thu, 30 Jan 2025 23:07:44 -0800 From: Christoph Hellwig To: Theodore Ts'o Cc: "Martin K. Petersen" , Kanchan Joshi , lsf-pc@lists.linux-foundation.org, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, josef@toxicpanda.com Subject: Re: [Lsf-pc] [LSF/MM/BPF TOPIC] File system checksum offload Message-ID: References: <20250130091545.66573-1-joshi.k@samsung.com> <20250130142857.GB401886@mit.edu> <20250131044015.GB416991@mit.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250131044015.GB416991@mit.edu> X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Thu, Jan 30, 2025 at 08:40:15PM -0800, Theodore Ts'o wrote: > On Thu, Jan 30, 2025 at 03:39:20PM -0500, Martin K. Petersen wrote: > > It already works that way. If a device advertises being > > integrity-capable, the block layer will automatically generate > > protection information on write and verify received protection > > information on read. Leveraging hardware-accelerated CRC calculation if > > the CPU is capable (PCLMULQDQ, etc.). > > So I'm confused. If that's the case, why do we need Kanchan Joshi's > patch to set some magic bio flag and adding a mount option to btrfs? Well, as stated in reply to the series there really isn't. The case with a buffer duplicates the existing auto-PI in the block layer, and the no-buffer cases reduces the protection envelope compared to using the auto PI.