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spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:51094 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ligxu-0005DS-3d for qemu-devel@archiver.kernel.org; Mon, 17 May 2021 13:23:38 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:41784) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ligYS-0005TN-Fq for qemu-devel@nongnu.org; Mon, 17 May 2021 12:57:22 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:49581) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ligYL-0008Kv-Kx for qemu-devel@nongnu.org; Mon, 17 May 2021 12:57:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1621270632; 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=KwC129NVrB5iB4tLmH9o7R2/Lw8GrQhLgAFNn041mKE=; b=OOEXfwqcrf6Z6WJTTABWvI6PksiAcDR9x5YFI4Dhn1edVs3zge4elrcYUxZsihCVyOMw6a S03ReCUpA0wPPo57wZcb4HcTt6tZzQdrbUQ+HzVEUCgIYi6MZPlb+6IzhI6yFge2RWkbni 1p3U+1JvQbB1Awc+Q75vAqbgd+A+Uvs= 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-234-I0QKvSixNc6_-mwMm59d7A-1; Mon, 17 May 2021 12:57:09 -0400 X-MC-Unique: I0QKvSixNc6_-mwMm59d7A-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C03858015F5; Mon, 17 May 2021 16:57:08 +0000 (UTC) Received: from dresden.str.redhat.com (ovpn-113-29.ams2.redhat.com [10.36.113.29]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A1B3A2B6C4; Mon, 17 May 2021 16:57:06 +0000 (UTC) Subject: Re: [PATCH 08/21] block/backup: stricter backup_calculate_cluster_size() To: Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org References: <20210517064428.16223-1-vsementsov@virtuozzo.com> <20210517064428.16223-10-vsementsov@virtuozzo.com> From: Max Reitz Message-ID: Date: Mon, 17 May 2021 18:57:05 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <20210517064428.16223-10-vsementsov@virtuozzo.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 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=170.10.133.124; envelope-from=mreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.374, 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=unavailable 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: kwolf@redhat.com, berrange@redhat.com, ehabkost@redhat.com, jsnow@redhat.com, qemu-devel@nongnu.org, armbru@redhat.com, den@openvz.org, pbonzini@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 17.05.21 08:44, Vladimir Sementsov-Ogievskiy wrote: > No reason to tolerate bdrv_get_info() errors except for ENOTSUP. Let's > just error-out, it's simpler and safer. Hm, doesn’t look that much simpler to me. Not sure how much safer it is, because the point was that in the target_does_cow case, we would like a cluster size hint, but it isn’t necessary. So if we don’t get one, regardless of the reason, we use the default cluster size. I don’t know why ENOTSUP should be treated in a special way there. So I don’t know. Max > Signed-off-by: Vladimir Sementsov-Ogievskiy > --- > block/backup.c | 14 +++++--------- > 1 file changed, 5 insertions(+), 9 deletions(-) > > diff --git a/block/backup.c b/block/backup.c > index fe685e411b..fe7a1f1e37 100644 > --- a/block/backup.c > +++ b/block/backup.c > @@ -367,7 +367,10 @@ static int64_t backup_calculate_cluster_size(BlockDriverState *target, > * targets with a backing file, try to avoid COW if possible. > */ > ret = bdrv_get_info(target, &bdi); > - if (ret == -ENOTSUP && !target_does_cow) { > + if (ret < 0 && ret != -ENOTSUP) { > + error_setg_errno(errp, -ret, "Failed to get target info"); > + return ret; > + } else if (ret == -ENOTSUP && !target_does_cow) { > /* Cluster size is not defined */ > warn_report("The target block device doesn't provide " > "information about the block size and it doesn't have a " > @@ -376,14 +379,7 @@ static int64_t backup_calculate_cluster_size(BlockDriverState *target, > "this default, the backup may be unusable", > BACKUP_CLUSTER_SIZE_DEFAULT); > return BACKUP_CLUSTER_SIZE_DEFAULT; > - } else if (ret < 0 && !target_does_cow) { > - error_setg_errno(errp, -ret, > - "Couldn't determine the cluster size of the target image, " > - "which has no backing file"); > - error_append_hint(errp, > - "Aborting, since this may create an unusable destination image\n"); > - return ret; > - } else if (ret < 0 && target_does_cow) { > + } else if (ret == -ENOTSUP && target_does_cow) { > /* Not fatal; just trudge on ahead. */ > return BACKUP_CLUSTER_SIZE_DEFAULT; > } >