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=-8.1 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,URIBL_BLOCKED,USER_AGENT_SANE_1 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 BAD3DC5DF61 for ; Thu, 7 Nov 2019 12:01:14 +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 82ACD2187F for ; Thu, 7 Nov 2019 12:01:14 +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="TeruM6HC" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 82ACD2187F 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]:41330 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iSgTR-0006IK-OW for qemu-devel@archiver.kernel.org; Thu, 07 Nov 2019 07:01:13 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:53391) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iSgRe-000557-GF for qemu-devel@nongnu.org; Thu, 07 Nov 2019 06:59:24 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iSgRc-0002O8-9d for qemu-devel@nongnu.org; Thu, 07 Nov 2019 06:59:22 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:34202 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iSgRc-0002Nw-5i for qemu-devel@nongnu.org; Thu, 07 Nov 2019 06:59:20 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1573127959; 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=1Dv3Lv/FGMLZRyrTrfPXhI8m7bhTpGGzK5dX3LzhsDo=; b=TeruM6HCRrU9/2av5joDpLZM/p/H/zdXxm0dpC97X/40dDRD3YkGxTpZLzqrrAlFfJtHDj eH/RJq+fetI4jpQlO9A/br5b0WyzkWZJTSG3fFJTzOo+OXVaWatnXHW+7L1K7n9HGwHGwk jevCvBNkINVeyRlFmghsYLQKjAQnF2k= 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-363-em20_29AO4egd02Kp2nYpA-1; Thu, 07 Nov 2019 06:59:15 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 642748017DD; Thu, 7 Nov 2019 11:59:14 +0000 (UTC) Received: from work-vm (unknown [10.36.118.14]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 816995D9CD; Thu, 7 Nov 2019 11:59:13 +0000 (UTC) Date: Thu, 7 Nov 2019 11:59:10 +0000 From: "Dr. David Alan Gilbert" To: Wei Yang Subject: Re: [PATCH 1/2] migration/compress: compress QEMUFile is not writable Message-ID: <20191107115910.GG2816@work-vm> References: <20191012023932.1863-1-richardw.yang@linux.intel.com> <20191012023932.1863-2-richardw.yang@linux.intel.com> MIME-Version: 1.0 In-Reply-To: <20191012023932.1863-2-richardw.yang@linux.intel.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-MC-Unique: em20_29AO4egd02Kp2nYpA-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 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: qemu-devel@nongnu.org, quintela@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Wei Yang (richardw.yang@linux.intel.com) wrote: > We open a file with empty_ops for compress QEMUFile, which means this is > not writable. That explanation sounds reasonable; but I'm confused by the history of this; the code was added by Liang Li in : b3be289 qemu-file: Fix qemu_put_compression_data flaw ( https://www.mail-archive.com/qemu-devel@nongnu.org/msg368974.html ) with almost exactly the opposite argument; can we figure out why? Dave > Signed-off-by: Wei Yang > --- > migration/qemu-file.c | 16 +++------------- > 1 file changed, 3 insertions(+), 13 deletions(-) >=20 > diff --git a/migration/qemu-file.c b/migration/qemu-file.c > index 26fb25ddc1..f3d99a96ec 100644 > --- a/migration/qemu-file.c > +++ b/migration/qemu-file.c > @@ -744,11 +744,8 @@ static int qemu_compress_data(z_stream *stream, uint= 8_t *dest, size_t dest_len, > /* Compress size bytes of data start at p and store the compressed > * data to the buffer of f. > * > - * When f is not writable, return -1 if f has no space to save the > - * compressed data. > - * When f is wirtable and it has no space to save the compressed data, > - * do fflush first, if f still has no space to save the compressed > - * data, return -1. > + * Since the file is dummy file with empty_ops, return -1 if f has no sp= ace to > + * save the compressed data. > */ > ssize_t qemu_put_compression_data(QEMUFile *f, z_stream *stream, > const uint8_t *p, size_t size) > @@ -756,14 +753,7 @@ ssize_t qemu_put_compression_data(QEMUFile *f, z_str= eam *stream, > ssize_t blen =3D IO_BUF_SIZE - f->buf_index - sizeof(int32_t); > =20 > if (blen < compressBound(size)) { > - if (!qemu_file_is_writable(f)) { > - return -1; > - } > - qemu_fflush(f); > - blen =3D IO_BUF_SIZE - sizeof(int32_t); > - if (blen < compressBound(size)) { > - return -1; > - } > + return -1; > } > =20 > blen =3D qemu_compress_data(stream, f->buf + f->buf_index + sizeof(i= nt32_t), > --=20 > 2.17.1 >=20 -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK