From patchwork Sun Jun 28 11:02:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alberto Garcia X-Patchwork-Id: 279178 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=-9.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham 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 7ACECC433DF for ; Sun, 28 Jun 2020 11:16:05 +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 4529720B80 for ; Sun, 28 Jun 2020 11:16:05 +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="WA4O9jQ7" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4529720B80 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]:33316 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jpVI4-0002k0-Co for qemu-devel@archiver.kernel.org; Sun, 28 Jun 2020 07:16:04 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48458) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jpV6O-0007NF-HE; Sun, 28 Jun 2020 07:04:00 -0400 Received: from fanzine.igalia.com ([178.60.130.6]:42398) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jpV6J-0000XR-U9; Sun, 28 Jun 2020 07:04:00 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From; bh=9sinAT98PUzgL4pBz7R1BbWSmbQmOO5Lnaa9e5wFELw=; b=WA4O9jQ7JPNVC2xRTTbdadG9QSxrpZ5HON01X7Bh8SL1kF2JhwxT2KZn+gXu5ttLpU207TMKbdiWFnJaUkaoCqloMfPR7UDG+KtG+84+wxlJnU46tDL+RvrMdiVuu02NKva8eZz8S8rIvRP22Vg9xiBeIdsPOqFwYHuyKGZF49av0T9gecPEBu/mvImemnV+ltCrVKaWHKdMAoEgsa+ZB8CwAv5EoIkfS09Mwc34JPUqEm75kp4hXru2mGUPRG5yhG/+zLmMIgRvIy2DgWQPazRcylIkgZO0k4H2SxVv5i5GByTjjmg0MPgCTdhK62g3von7OieFi9/yfGWrEin1jA==; Received: from 26.red-79-158-236.dynamicip.rima-tde.net ([79.158.236.26] helo=perseus.local) by fanzine.igalia.com with esmtpsa (Cipher TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim) id 1jpV5Y-0002gl-8y; Sun, 28 Jun 2020 13:03:09 +0200 Received: from berto by perseus.local with local (Exim 4.92) (envelope-from ) id 1jpV5I-00038v-4D; Sun, 28 Jun 2020 13:02:52 +0200 From: Alberto Garcia To: qemu-devel@nongnu.org Subject: [PATCH v9 22/34] qcow2: Add subcluster support to zero_in_l2_slice() Date: Sun, 28 Jun 2020 13:02:31 +0200 Message-Id: <7551704955c6ea570af4053fb86da5b3a33493c4.1593342067.git.berto@igalia.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: References: MIME-Version: 1.0 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 = 2020/06/28 07:03:08 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_HELO_NONE=0.001, 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 , Alberto Garcia , qemu-block@nongnu.org, Derek Su , Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" The QCOW_OFLAG_ZERO bit that indicates that a cluster reads as zeroes is only used in standard L2 entries. Extended L2 entries use individual 'all zeroes' bits for each subcluster. This must be taken into account when updating the L2 entry and also when deciding that an existing entry does not need to be updated. Signed-off-by: Alberto Garcia Reviewed-by: Eric Blake --- block/qcow2-cluster.c | 36 +++++++++++++++++++----------------- 1 file changed, 19 insertions(+), 17 deletions(-) diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 2f3bd3a882..4e59bbd545 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -1956,7 +1956,6 @@ static int zero_in_l2_slice(BlockDriverState *bs, uint64_t offset, int l2_index; int ret; int i; - bool unmap = !!(flags & BDRV_REQ_MAY_UNMAP); ret = get_cluster_table(bs, offset, &l2_slice, &l2_index); if (ret < 0) { @@ -1968,28 +1967,31 @@ static int zero_in_l2_slice(BlockDriverState *bs, uint64_t offset, assert(nb_clusters <= INT_MAX); for (i = 0; i < nb_clusters; i++) { - uint64_t old_offset; - QCow2ClusterType cluster_type; + uint64_t old_l2_entry = get_l2_entry(s, l2_slice, l2_index + i); + uint64_t old_l2_bitmap = get_l2_bitmap(s, l2_slice, l2_index + i); + QCow2ClusterType type = qcow2_get_cluster_type(bs, old_l2_entry); + bool unmap = (type == QCOW2_CLUSTER_COMPRESSED) || + ((flags & BDRV_REQ_MAY_UNMAP) && qcow2_cluster_is_allocated(type)); + uint64_t new_l2_entry = unmap ? 0 : old_l2_entry; + uint64_t new_l2_bitmap = old_l2_bitmap; - old_offset = get_l2_entry(s, l2_slice, l2_index + i); + if (has_subclusters(s)) { + new_l2_bitmap = QCOW_L2_BITMAP_ALL_ZEROES; + } else { + new_l2_entry |= QCOW_OFLAG_ZERO; + } - /* - * Minimize L2 changes if the cluster already reads back as - * zeroes with correct allocation. - */ - cluster_type = qcow2_get_cluster_type(bs, old_offset); - if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN || - (cluster_type == QCOW2_CLUSTER_ZERO_ALLOC && !unmap)) { + if (old_l2_entry == new_l2_entry && old_l2_bitmap == new_l2_bitmap) { continue; } qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice); - if (cluster_type == QCOW2_CLUSTER_COMPRESSED || unmap) { - set_l2_entry(s, l2_slice, l2_index + i, QCOW_OFLAG_ZERO); - qcow2_free_any_clusters(bs, old_offset, 1, QCOW2_DISCARD_REQUEST); - } else { - uint64_t entry = get_l2_entry(s, l2_slice, l2_index + i); - set_l2_entry(s, l2_slice, l2_index + i, entry | QCOW_OFLAG_ZERO); + if (unmap) { + qcow2_free_any_clusters(bs, old_l2_entry, 1, QCOW2_DISCARD_REQUEST); + } + set_l2_entry(s, l2_slice, l2_index + i, new_l2_entry); + if (has_subclusters(s)) { + set_l2_bitmap(s, l2_slice, l2_index + i, new_l2_bitmap); } }