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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]:39408 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lP4VU-0004HE-2y for qemu-devel@archiver.kernel.org; Wed, 24 Mar 2021 10:29:12 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:50510) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lP4Sy-0001Mz-8i for qemu-devel@nongnu.org; Wed, 24 Mar 2021 10:26:36 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:29435) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lP4Sv-0004vW-1A for qemu-devel@nongnu.org; Wed, 24 Mar 2021 10:26:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1616595990; 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=S5iHfEIA3GDjFPgq6a/QcVRkgfVxVhxuHiiap4dnpak=; b=cVaG4Sngt+xPkKg9JGVAzUlNTQnOPk+1OwSERzhkZCbHOyh2k41fLTNnf8S+8Udpi/48HL jgxASVuZh9uLJkD5BcAQsVwUsEIz29OIQB4CFLVuz/u6P0OgtLrLlEWJZQahCavL75i9N3 ecZ6+tt9v9E3a5n5nnB+o0mGwEkPhrc= 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-25-JpIFyHNDOLm70nHH17b7yA-1; Wed, 24 Mar 2021 10:26:28 -0400 X-MC-Unique: JpIFyHNDOLm70nHH17b7yA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id AA4A280197D; Wed, 24 Mar 2021 14:25:59 +0000 (UTC) Received: from dresden.str.redhat.com (ovpn-113-161.ams2.redhat.com [10.36.113.161]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 93F405D766; Wed, 24 Mar 2021 14:25:58 +0000 (UTC) Subject: Re: [PATCH 2/6] block/vdi: Don't assume that blocks are larger than VdiHeader To: Paolo Bonzini , qemu-devel@nongnu.org References: <20210317180013.235231-1-pbonzini@redhat.com> <20210317180013.235231-3-pbonzini@redhat.com> From: Max Reitz Message-ID: <082a32cc-c09e-522d-429d-49a1727c81f5@redhat.com> Date: Wed, 24 Mar 2021 15:25:57 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: <20210317180013.235231-3-pbonzini@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 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 Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=mreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no 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: david.edmondson@oracle.com, kwolf@redhat.com, qemu-block@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 17.03.21 19:00, Paolo Bonzini wrote: > From: David Edmondson > > Given that the block size is read from the header of the VDI file, a > wide variety of sizes might be seen. Rather than re-using a block > sized memory region when writing the VDI header, allocate an > appropriately sized buffer. > > Signed-off-by: David Edmondson > Message-Id: <20210309144015.557477-3-david.edmondson@oracle.com> > Signed-off-by: Paolo Bonzini > --- > block/vdi.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/block/vdi.c b/block/vdi.c > index 2a6dc26124..548f8a057b 100644 > --- a/block/vdi.c > +++ b/block/vdi.c > @@ -696,18 +696,20 @@ nonallocating_write: > > if (block) { > /* One or more new blocks were allocated. */ > - VdiHeader *header = (VdiHeader *) block; > + VdiHeader *header; > uint8_t *base; > uint64_t offset; > uint32_t n_sectors; > > + g_free(block); This logic (checking @block != NULL) was a bit weird before and this just seems to accomodate it. We probably shouldn’t check @block, but some boolean, and *block should be freed after the while () loop. Considering the “if (block)” was there already and it’d be weird to keep that check if *block were freed by that point, I suppose this isn’t making it worse, though, so: Reviewed-by: Max Reitz > + header = g_malloc(sizeof(*header)); > + > logout("now writing modified header\n"); > assert(VDI_IS_ALLOCATED(bmap_first)); > *header = s->header; > vdi_header_to_le(header); > - ret = bdrv_pwrite(bs->file, 0, block, sizeof(VdiHeader)); > - g_free(block); > - block = NULL; > + ret = bdrv_pwrite(bs->file, 0, header, sizeof(*header)); > + g_free(header); > > if (ret < 0) { > return ret; >