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=-3.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 254CFC28CBC for ; Wed, 6 May 2020 15:03:49 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D98D620746 for ; Wed, 6 May 2020 15:03:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=igalia.com header.i=@igalia.com header.b="RC7DDxtg" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D98D620746 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=igalia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:48802 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jWLaN-0007f2-Vp for qemu-devel@archiver.kernel.org; Wed, 06 May 2020 11:03:47 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37948) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jWLZa-0006oW-FK; Wed, 06 May 2020 11:02:58 -0400 Received: from fanzine.igalia.com ([178.60.130.6]:49505) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jWLZY-0006ZY-4s; Wed, 06 May 2020 11:02:57 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Type:MIME-Version:Message-ID:Date:References:In-Reply-To:Subject:Cc:To:From; bh=sHIl9q4uSH0GC4zmVXN3kQnxRlJqRsrYbNBGHJkk3Tw=; b=RC7DDxtgEE01UUC2CowBApCH8aHpga3py+1zxJe+CryOANa1jYw11aXDz3HQ9WQDGEWon60r1nxTAD6llOrpA2WPbSKqXP4D9HjN5cLjjfqb3ttBrOjlEN+LWa+xd4c2AMAqKkT6QC7CRvGfDm1J9U6qMz65F3vN3PuSwuzIC3Yc8b4iiqn9AX/on79+mcxVKeNgaTByuqKj0DXoZNvGXOGJo1VcSMEbCsnEjH9l/Q4ujutj7ZiLXzNDGdww+L7Qicj3xvJSVUT7vRBWc+6NoDBUjlU0scgE2c+3oomAf+VYAOv+6X96qM3+G3+JfHha1QBsnzTThJCC1FVZtRpYGQ==; Received: from maestria.local.igalia.com ([192.168.10.14] helo=mail.igalia.com) by fanzine.igalia.com with esmtps (Cipher TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim) id 1jWLZU-0004SR-EH; Wed, 06 May 2020 17:02:52 +0200 Received: from berto by mail.igalia.com with local (Exim) id 1jWLZU-0001NW-3a; Wed, 06 May 2020 17:02:52 +0200 From: Alberto Garcia To: Eric Blake , qemu-devel@nongnu.org Subject: Re: [PATCH v5 07/31] qcow2: Document the Extended L2 Entries feature In-Reply-To: <52c059ee-8a80-89af-dbab-ffea3976421e@redhat.com> References: <52c059ee-8a80-89af-dbab-ffea3976421e@redhat.com> User-Agent: Notmuch/0.18.2 (http://notmuchmail.org) Emacs/24.4.1 (i586-pc-linux-gnu) Date: Wed, 06 May 2020 17:02:52 +0200 Message-ID: MIME-Version: 1.0 Content-Type: text/plain Received-SPF: pass client-ip=178.60.130.6; envelope-from=berto@igalia.com; helo=fanzine.igalia.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/06 11:02:53 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x (no timestamps) [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue 05 May 2020 09:35:06 PM CEST, Eric Blake wrote: > On 5/5/20 12:38 PM, Alberto Garcia wrote: >> Subcluster allocation in qcow2 is implemented by extending the >> existing L2 table entries and adding additional information to >> indicate the allocation status of each subcluster. >> >> This patch documents the changes to the qcow2 format and how they >> affect the calculation of the L2 cache size. >> >> Signed-off-by: Alberto Garcia >> Reviewed-by: Max Reitz >> --- >> docs/interop/qcow2.txt | 68 ++++++++++++++++++++++++++++++++++++++++-- >> docs/qcow2-cache.txt | 19 +++++++++++- >> 2 files changed, 83 insertions(+), 4 deletions(-) >> > >> @@ -547,7 +557,8 @@ Standard Cluster Descriptor: >> nor is data read from the backing file if the cluster is >> unallocated. >> >> - With version 2, this is always 0. >> + With version 2 or with extended L2 entries (see the next >> + section), this is always 0. > > In your cover letter, you said you changed things to tolerate this bit > being set even with extended L2 entries. Does this sentence need a > tweak? Not a bad idea. >> +The last 64 bits contain a subcluster allocation bitmap with this format: >> + >> +Subcluster Allocation Bitmap (for standard clusters): >> + >> + Bit 0 - 31: Allocation status (one bit per subcluster) > > Why two spaces after '-'? No reason, I guess I just didn't notice. I'll fix it. Berto