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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 E80F2C433E0 for ; Fri, 22 Jan 2021 08:26:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A273E23381 for ; Fri, 22 Jan 2021 08:26:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726457AbhAVIZo (ORCPT ); Fri, 22 Jan 2021 03:25:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726117AbhAVIZ3 (ORCPT ); Fri, 22 Jan 2021 03:25:29 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8E6B0C06174A; Fri, 22 Jan 2021 00:24:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; 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=72GbwhSaNm+KhJ5+LNT/6O1Ghfel0X9o+LJMfhOiuQk=; b=IQkHaX7tWmIiZsoJtwtMD5PQh6 6sSMyLyDrUNouXEQbmbUFvF24EdKoRDQa0ZVLwmyKYTwKkk5xp0VZU5CE31ATf2ZiFwwXx2JWbobI L6BxLzzOyWotGM5q0hLW/+GqNioImLvxzCtdhYXF4e+LcRdZ1djRabadZ94sEhJbx2J7UPgXgvjfa tqDLPtgWNi4VqC7fTxuk4GVga87ZtHgv2MpOkaBZNnosvzNqcAZirFHTO8gkgafO10FkseKAjRJRH pPnEAyzULxisEGO6ubnq1mviR0vHDhTSpgRApSNaMNMdIYD05p10HJrJYd5YtG0+6ZmbWyHSwiX+4 B1c4lT/Q==; Received: from hch by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1l2rj0-000VVB-L7; Fri, 22 Jan 2021 08:23:27 +0000 Date: Fri, 22 Jan 2021 08:23:22 +0000 From: Christoph Hellwig To: David Howells Cc: "J. Bruce Fields" , Trond Myklebust , Anna Schumaker , Steve French , Dominique Martinet , Takashi Iwai , Matthew Wilcox , linux-afs@lists.infradead.org, Jeff Layton , David Wysochanski , Alexander Viro , linux-cachefs@redhat.com, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs-developer@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC][PATCH 00/25] Network fs helper library & fscache kiocb API Message-ID: <20210122082322.GB119852@infradead.org> References: <20210121174306.GB20964@fieldses.org> <20210121164645.GA20964@fieldses.org> <161118128472.1232039.11746799833066425131.stgit@warthog.procyon.org.uk> <1794286.1611248577@warthog.procyon.org.uk> <1851804.1611255313@warthog.procyon.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1851804.1611255313@warthog.procyon.org.uk> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org On Thu, Jan 21, 2021 at 06:55:13PM +0000, David Howells wrote: > > Is it that those "bridging" blocks only show up in certain corner cases > > that users can arrange to avoid? Or that it's OK as long as you use > > certain specific file systems whose behavior goes beyond what's > > technically required by the bamp or seek interfaces? > > That's a question for the xfs, ext4 and btrfs maintainers, and may vary > between kernel versions and fsck or filesystem packing utility versions. For XFS if you do not use reflinks, extent size hints or the RT subvolume there are no new allocations before i_size that will magically show up. But relying on such undocumented assumptions is very dangerous.