From patchwork Mon Jul 6 10:04:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 278458 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=-6.5 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 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 712F5C433DF for ; Mon, 6 Jul 2020 10:16:12 +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 3B4732075B for ; Mon, 6 Jul 2020 10:16:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="VmFP5HsQ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3B4732075B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:60244 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jsOAV-0007J6-EU for qemu-devel@archiver.kernel.org; Mon, 06 Jul 2020 06:16:11 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53974) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jsO0J-0004I7-BC for qemu-devel@nongnu.org; Mon, 06 Jul 2020 06:05:39 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:49285 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jsO0F-0004Ct-VL for qemu-devel@nongnu.org; Mon, 06 Jul 2020 06:05:38 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1594029934; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=kI1zbjHnldHAj8UOQoPhhm9DhNupfZgrzUf+cR5juJ8=; b=VmFP5HsQkdYF8LzAw37lSlI3eeSPl2ggsIyGsU3lmNoMl+JHCFwmmRG8o/w6758Gq+Khc/ 2OTX+OsNeLD8WJWbutv99n9Z4l/crw2SQNqZKOzHo2IywUmDNYNGXWz5W0js8L6puXT7Mj CMR3uAT8GwjEPHdDkh9AgxzffhUzue4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-139-55lDmRRoPySxkpxzOdFNKA-1; Mon, 06 Jul 2020 06:05:32 -0400 X-MC-Unique: 55lDmRRoPySxkpxzOdFNKA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 64DED107ACCA; Mon, 6 Jul 2020 10:05:31 +0000 (UTC) Received: from localhost (ovpn-112-176.ams2.redhat.com [10.36.112.176]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 08D75619C4; Mon, 6 Jul 2020 10:05:30 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Subject: [PULL 24/31] block/vdi: return ZERO block-status when appropriate Date: Mon, 6 Jul 2020 12:04:25 +0200 Message-Id: <20200706100432.2301919-25-mreitz@redhat.com> In-Reply-To: <20200706100432.2301919-1-mreitz@redhat.com> References: <20200706100432.2301919-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=207.211.31.120; envelope-from=mreitz@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/06 01:52:41 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -40 X-Spam_score: -4.1 X-Spam_bar: ---- X-Spam_report: (-4.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-1, SPF_HELO_NONE=0.001, SPF_PASS=-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 , Peter Maydell , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Vladimir Sementsov-Ogievskiy In case of !VDI_IS_ALLOCATED[], we do zero out the corresponding chunk of qiov. So, this should be reported as ZERO. Note that this changes visible output of "qemu-img map --output=json" and "qemu-io -c map" commands. For qemu-img map, the change is obvious: we just mark as zero what is really zero. For qemu-io it's less obvious: what was unallocated now is allocated. There is an inconsistency in understanding of unallocated regions in Qemu: backing-supporting format-drivers return 0 block-status to report go-to-backing logic for this area. Some protocol-drivers (iscsi) return 0 to report fs-unallocated-non-zero status (i.e., don't occupy space on disk, read result is undefined). BDRV_BLOCK_ALLOCATED is defined as something more close to go-to-backing logic. Still it is calculated as ZERO | DATA, so 0 from iscsi is treated as unallocated. It doesn't influence backing-chain behavior, as iscsi can't have backing file. But it does influence "qemu-io -c map". We should solve this inconsistency at some future point. Now, let's just make backing-not-supporting format drivers (vdi at this patch and vpc with the following) to behave more like backing-supporting drivers and not report 0 block-status. More over, returning ZERO status is absolutely valid thing, and again, corresponds to how the other format-drivers (backing-supporting) work. After block-status update, it never reports 0, so setting unallocated_blocks_are_zero doesn't make sense (as the only user of it is bdrv_co_block_status and it checks unallocated_blocks_are_zero only for unallocated areas). Drop it. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Eric Blake Message-Id: <20200528094405.145708-4-vsementsov@virtuozzo.com> Signed-off-by: Max Reitz --- block/vdi.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/block/vdi.c b/block/vdi.c index 2f506a01ba..c4527a9d8c 100644 --- a/block/vdi.c +++ b/block/vdi.c @@ -334,7 +334,6 @@ static int vdi_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) logout("\n"); bdi->cluster_size = s->block_size; bdi->vm_state_offset = 0; - bdi->unallocated_blocks_are_zero = true; return 0; } @@ -536,7 +535,7 @@ static int coroutine_fn vdi_co_block_status(BlockDriverState *bs, *pnum = MIN(s->block_size - index_in_block, bytes); result = VDI_IS_ALLOCATED(bmap_entry); if (!result) { - return 0; + return BDRV_BLOCK_ZERO; } *map = s->header.offset_data + (uint64_t)bmap_entry * s->block_size +