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 Received: from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 63D7ECA6007 for ; Wed, 7 Oct 2026 15:20:01 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1xETQg-0004qi-5j; Wed, 07 Oct 2026 11:19:38 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1xETQe-0004qZ-EU for qemu-devel@nongnu.org; Wed, 07 Oct 2026 11:19:36 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1xETQc-000762-AL for qemu-devel@nongnu.org; Wed, 07 Oct 2026 11:19:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1791386373; 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: in-reply-to:in-reply-to:references:references; bh=seVxlGkttiaK8uCT+wl1Qxj5maRR6ZZs6gB425/uzmQ=; b=B1lB+FQd+9wekG2Q0Td0CRl/DJgSCc53oW2hE1+UYNFeBn9HBXdjXV2JitDOTsR8Hbkeue FZPnTwqCQpUSnzE4mxW5Ie5DnmA2SgIkoulZAqEEl+vQqtMyPIopvUuHZqKtvZ6aIO/d9K d5v+aueKby3pt0gGi6xjKhaZ537pPNs= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-86-RUcOCQUJP6iOwqPO9E_-Gg-1; Wed, 7 Oct 2026 15:19:30 +0000 X-MC-Unique: RUcOCQUJP6iOwqPO9E_-Gg-1 X-Mimecast-MFC-AGG-ID: RUcOCQUJP6iOwqPO9E_-Gg_1791386369 Received: from mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.95]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B7F4A1955F25; Wed, 7 Oct 2026 15:19:29 +0000 (UTC) Received: from redhat.com (unknown [10.44.32.219]) by mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 0E5035BC; Wed, 7 Oct 2026 15:19:27 +0000 (UTC) Date: Wed, 7 Oct 2026 17:19:25 +0200 From: Kevin Wolf To: Sanne Raymaekers Cc: qemu-devel@nongnu.org, hreitz@redhat.com, fam@euphon.net Subject: Re: [PATCH 3/3] block/vmdk: add eos marker for stream optimized disks Message-ID: References: <20261005133316.198087-1-sraymaek@redhat.com> <20261005133316.198087-3-sraymaek@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261005133316.198087-3-sraymaek@redhat.com> X-Scanned-By: MIMEDefang 3.6 on 10.30.177.95 Received-SPF: pass client-ip=170.10.133.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: 10 X-Spam_score: 1.0 X-Spam_bar: + X-Spam_report: (1.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.24, 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_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_SBL_CSS=3.335, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Am 05.10.2026 um 15:33 hat Sanne Raymaekers geschrieben: > The end of stream marker should be at the very end of a stream optimized > disk. It consists of a regular marker struct with `val`, `size` and > `type` set to 0. It is then padded with more 0s to fill out a > sector. This effectively results in 512 zero bytes.[^1] > > [^1] Virtual Disk Format 5.0 Technical Note. > > Signed-off-by: Sanne Raymaekers > --- > block/vmdk.c | 29 +++++++++++++++++++++++------ > 1 file changed, 23 insertions(+), 6 deletions(-) > > diff --git a/block/vmdk.c b/block/vmdk.c > index 040f38cd1d..c10321146e 100644 > --- a/block/vmdk.c > +++ b/block/vmdk.c > @@ -195,6 +195,13 @@ typedef struct VmdkGrainMarker { > uint8_t data[]; > } QEMU_PACKED VmdkGrainMarker; > > +typedef struct EosMarker { > + uint64_t val; > + uint32_t size; > + uint32_t type; > + uint8_t pad[512 - 16]; > +} QEMU_PACKED EosMarker; > + > enum { > MARKER_END_OF_STREAM = 0, > MARKER_GRAIN_TABLE = 1, > @@ -987,12 +994,7 @@ vmdk_open_vmdk4(BlockDriverState *bs, BdrvChild *file, int flags, > VMDK4Header header; > uint8_t pad[512 - 4 - sizeof(VMDK4Header)]; > > - struct { > - uint64_t val; > - uint32_t size; > - uint32_t type; > - uint8_t pad[512 - 16]; > - } QEMU_PACKED eos_marker; > + EosMarker eos_marker; > } QEMU_PACKED footer; > > ret = bdrv_pread(file, bs->file->bs->total_sectors * 512 - 1536, > @@ -2180,6 +2182,7 @@ vmdk_co_pwritev_compressed(BlockDriverState *bs, int64_t offset, int64_t bytes, > BDRVVmdkState *s = bs->opaque; > int i, ret; > int64_t length; > + EosMarker *eos_marker = NULL; > > for (i = 0; i < s->num_extents; i++) { > length = bdrv_co_getlength(s->extents[i].file->bs); > @@ -2193,6 +2196,20 @@ vmdk_co_pwritev_compressed(BlockDriverState *bs, int64_t offset, int64_t bytes, > return ret; > } > } Is there any way s->num_extents could not be 1 for streamOptimized images? If not, I think you can delete the whole existing for loop (which will execute only once). bdrv_co_truncate() extends the file size, but then you write at a higher offset below, which will extend it a second time, so the bdrv_co_truncate() call didn't do anything useful. > + /* Stream optimized disks end with an EOS marker, consisting of 512 null bytes. */ > + if (strcmp(s->create_type, "streamOptimized") == 0) { This is vmdk_co_pwritev_compressed(). If we're here, we already know that this is a streamOptimized image. > + eos_marker = g_malloc(sizeof(EosMarker)); > + memset(eos_marker, 0, sizeof(EosMarker)); This can be combined into g_malloc0(). In fact, using qemu_blockalign0() and declaring eos_marker as QEMU_AUTO_VFREE would be even better because it makes sure that the buffer has the required memory alignment; otherwise, a lower layer may have to copy the data into a bounce buffer. > + length = bdrv_co_getlength(s->extents[s->num_extents - 1].file->bs); Unless I'm mistaken above, this is always s->extents[0]. bdrv_co_getlength() errors must be handled, like in the for loop above. > + ret = bdrv_co_pwrite(s->extents[s->num_extents - 1].file, length, > + sizeof(EosMarker), eos_marker, 0); When removing the truncate, length would become QEMU_ALIGN_UP(length, 512) here instead. > + g_free(eos_marker); > + if (ret < 0) { > + return ret; > + } > + } > + > return 0; > } > return vmdk_co_pwritev(bs, offset, bytes, qiov, 0); Kevin