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 AC31813A3ED; Fri, 31 Jan 2025 07:07:49 +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=1738307272; cv=none; b=CIW0N9GOzrMQ0pjDUcU4teJvE/5q9t7gZKARNwSA0kANmSg7jD6YrZCoKTI/eGZGM6++HIpGvpv/8CWsRL2epX5/PYTXgzL+QTA+/EeT692AicvhNGdgcE41orsZY8+xKiiFduX2mVDuY+1G4jMcuPKaUo7J+6sZm7JpwAP+ESw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738307272; c=relaxed/simple; bh=yF9eVRU9oSJPqBIYBBVDPJR3R0AGMgmsbXNsMW8bBAw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=SDFr/GdgCV4D/1126mTIeuN+zNcr6LKFxpAsJA78G71V68YqxT2Yns0BjdLGKLWarSMEXLF1Vu4gBZCvPxoasnOmtItGzbxcr2iy74QByGDJXkzyT4fg2+ObhyNPOZxH8P0uXKo0FG6X1FCgzOsWhmHjfwRdSgLN+AF6hNo3p0Y= 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=sVHrj2JB; 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="sVHrj2JB" 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=BuNkhA4U2EXzY3UIav9rX8ABnEiVHzXbjByWKZyeJio=; b=sVHrj2JBnjKfGR4qyrfUZ+JM80 P2mJ5gTCoRKUZtdYm8JjQmtzAjy7JsUB/JbxUdSByrcCN5iSrEyC8ae5xNJJGG/9f3O0SslEgb/h4 Pov7iB9r+FXsESIAyr/vFoJWlhJErtG8DDYlohxJLowqi6W03ZArdrhMI7dkXW/C/idDNkzMJegT6 YzbgnAcBiBpnai9F5S3eeGn7MDzuNsnGqbkC8xNT+jboeCkYLcWWkvQydhc0x1x6zLFG6LBDdU1qM zucAZLp+XrdlqKTPIybhZfO4BR6k2M8QJT0GdRXkzNhrPyaaTtqJA3lYJsIsPXOsvKB46fKOiDwXi xnkzfAUA==; 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> 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: <20250131044015.GB416991@mit.edu> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html 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.