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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 618F5C3F68F for ; Fri, 31 Jan 2020 20:04:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 384E2214D8 for ; Fri, 31 Jan 2020 20:04:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726102AbgAaUEW (ORCPT ); Fri, 31 Jan 2020 15:04:22 -0500 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:46105 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725954AbgAaUEW (ORCPT ); Fri, 31 Jan 2020 15:04:22 -0500 Received: from callcc.thunk.org (guestnat-104-133-9-100.corp.google.com [104.133.9.100] (may be forged)) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 00VK4CxZ015136 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 31 Jan 2020 15:04:14 -0500 Received: by callcc.thunk.org (Postfix, from userid 15806) id A7F13420324; Fri, 31 Jan 2020 15:04:11 -0500 (EST) Date: Fri, 31 Jan 2020 15:04:11 -0500 From: "Theodore Y. Ts'o" To: "Darrick J. Wong" Cc: lsf-pc@lists.linux-foundation.org, linux-fsdevel , linux-xfs , linux-block@vger.kernel.org, martin.petersen@oracle.com, Allison Collins , bob.liu@oracle.com Subject: Re: [LSF/MM/BPF TOPIC] selectively cramming things onto struct bio Message-ID: <20200131200411.GF332835@mit.edu> References: <20200131004447.GA6869@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200131004447.GA6869@magnolia> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Thu, Jan 30, 2020 at 04:44:47PM -0800, Darrick J. Wong wrote: > Hi everyone, > > Several months ago, there was a discussion[1] about enhancing XFS to > take a more active role in recoverying damaged blocks from a redundant > storage device when the block device doesn't signal an error but the > filesystem can tell that something is wrong. > > Yes, we (XFS) would like to be able to exhaust all available storage > redundancy before we resort to rebuilding lost metadata, and we'd like > to do that without implementing our own RAID layer. > > In the end, the largest stumbling block seems to be how to attach > additional instructions to struct bio. Jens rejected the idea of adding > more pointers or more bytes to a struct bio since we'd be forcing > everyone to pay the extra memory price for a feature that in the ideal > situation will be used infrequently. I'd be interested in this discussion as well; the issue came up when adding support for hardware-based inline-crypto support. - Ted