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=-6.8 required=3.0 tests=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 876A2C4CEC4 for ; Wed, 18 Sep 2019 20:54:09 +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 56DF320665 for ; Wed, 18 Sep 2019 20:54:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 56DF320665 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]:35208 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iAgxk-0007XZ-AF for qemu-devel@archiver.kernel.org; Wed, 18 Sep 2019 16:54:08 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:47048) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iAgve-0005qJ-Ke for qemu-devel@nongnu.org; Wed, 18 Sep 2019 16:51:59 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iAgvd-0008Fq-C6 for qemu-devel@nongnu.org; Wed, 18 Sep 2019 16:51:58 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57922) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iAgva-0008En-I7; Wed, 18 Sep 2019 16:51:54 -0400 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 mx1.redhat.com (Postfix) with ESMTPS id D691C3B714; Wed, 18 Sep 2019 20:51:53 +0000 (UTC) Received: from maximlenovopc.usersys.redhat.com (unknown [10.35.206.53]) by smtp.corp.redhat.com (Postfix) with ESMTP id 845DA60C18; Wed, 18 Sep 2019 20:51:49 +0000 (UTC) Message-ID: From: Maxim Levitsky To: Max Reitz , qemu-block@nongnu.org Date: Wed, 18 Sep 2019 23:51:48 +0300 In-Reply-To: <20190918095144.955-7-mreitz@redhat.com> References: <20190918095144.955-1-mreitz@redhat.com> <20190918095144.955-7-mreitz@redhat.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Wed, 18 Sep 2019 20:51:53 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH 6/8] block: Let format drivers pass @exact 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 , Fam Zheng , qemu-devel@nongnu.org, Stefan Hajnoczi Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, 2019-09-18 at 11:51 +0200, Max Reitz wrote: > When truncating a format node, the @exact parameter is generally handled > simply by virtue of the format storing the new size in the image > metadata. Such formats do not need to pass on the parameter to their > file nodes. > > There are exceptions, though: > - raw and crypto cannot store the image size, and thus must pass on > @exact. > > - When using qcow2 with an external data file, it just makes sense to > keep its size in sync with the qcow2 virtual disk (because the > external data file is the virtual disk). Therefore, we should pass > @exact when truncating it. > > Signed-off-by: Max Reitz > --- > block/crypto.c | 2 +- > block/qcow2.c | 15 ++++++++++++++- > block/raw-format.c | 2 +- > 3 files changed, 16 insertions(+), 3 deletions(-) > > diff --git a/block/crypto.c b/block/crypto.c > index e5a1a2cdf3..24823835c1 100644 > --- a/block/crypto.c > +++ b/block/crypto.c > @@ -311,7 +311,7 @@ block_crypto_co_truncate(BlockDriverState *bs, int64_t offset, bool exact, > > offset += payload_offset; > > - return bdrv_co_truncate(bs->file, offset, false, prealloc, errp); > + return bdrv_co_truncate(bs->file, offset, exact, prealloc, errp); > } > > static void block_crypto_close(BlockDriverState *bs) > diff --git a/block/qcow2.c b/block/qcow2.c > index 157b9b75d9..4ef19dd29a 100644 > --- a/block/qcow2.c > +++ b/block/qcow2.c > @@ -3822,6 +3822,13 @@ static int coroutine_fn qcow2_co_truncate(BlockDriverState *bs, int64_t offset, > if ((last_cluster + 1) * s->cluster_size < old_file_size) { > Error *local_err = NULL; > > + /* > + * Do not pass @exact here: It will not help the user if > + * we get an error here just because they wanted to shrink > + * their qcow2 image (on a block device) with qemu-img. > + * (And on the qcow2 layer, the @exact requirement is > + * always fulfilled, so there is no need to pass it on.) > + */ > bdrv_co_truncate(bs->file, (last_cluster + 1) * s->cluster_size, > false, PREALLOC_MODE_OFF, &local_err); > if (local_err) { > @@ -3840,7 +3847,12 @@ static int coroutine_fn qcow2_co_truncate(BlockDriverState *bs, int64_t offset, > switch (prealloc) { > case PREALLOC_MODE_OFF: > if (has_data_file(bs)) { > - ret = bdrv_co_truncate(s->data_file, offset, false, prealloc, errp); > + /* > + * If the caller wants an exact resize, the external data > + * file should be resized to the exact target size, too, > + * so we pass @exact here. > + */ > + ret = bdrv_co_truncate(s->data_file, offset, exact, prealloc, errp); > if (ret < 0) { > goto fail; > } > @@ -3925,6 +3937,7 @@ static int coroutine_fn qcow2_co_truncate(BlockDriverState *bs, int64_t offset, > /* Allocate the data area */ > new_file_size = allocation_start + > nb_new_data_clusters * s->cluster_size; > + /* Image file grows, so @exact does not matter */ > ret = bdrv_co_truncate(bs->file, new_file_size, false, prealloc, errp); > > if (ret < 0) { > error_prepend(errp, "Failed to resize underlying file: "); > diff --git a/block/raw-format.c b/block/raw-format.c > index 57d84d0bae..3a76ec7dd2 100644 > --- a/block/raw-format.c > +++ b/block/raw-format.c > @@ -387,7 +387,7 @@ static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t offset, > > s->size = offset; > offset += s->offset; > - return bdrv_co_truncate(bs->file, offset, false, prealloc, errp); > + return bdrv_co_truncate(bs->file, offset, exact, prealloc, errp); > } > > static void raw_eject(BlockDriverState *bs, bool eject_flag) Looks all right. Reviewed-by: Maxim Levitsky Best regards, Maxim Levitsky