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, URIBL_BLOCKED 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 88FC2C31E40 for ; Fri, 9 Aug 2019 16:22:39 +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 3A5B220C01 for ; Fri, 9 Aug 2019 16:22:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3A5B220C01 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]:60956 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hw7f4-0003MH-Gy for qemu-devel@archiver.kernel.org; Fri, 09 Aug 2019 12:22:38 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:56991) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hw7XM-00013h-Cd for qemu-devel@nongnu.org; Fri, 09 Aug 2019 12:14:41 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hw7XL-00046J-7p for qemu-devel@nongnu.org; Fri, 09 Aug 2019 12:14:40 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52036) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hw7XI-000424-J7; Fri, 09 Aug 2019 12:14:36 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C190059451; Fri, 9 Aug 2019 16:14:34 +0000 (UTC) Received: from localhost (unknown [10.40.205.179]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5B3C95C8BA; Fri, 9 Aug 2019 16:14:34 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Fri, 9 Aug 2019 18:13:36 +0200 Message-Id: <20190809161407.11920-12-mreitz@redhat.com> In-Reply-To: <20190809161407.11920-1-mreitz@redhat.com> References: <20190809161407.11920-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Fri, 09 Aug 2019 16:14:34 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v6 11/42] block: Add bdrv_supports_compressed_writes() 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 , Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Filters cannot compress data themselves but they have to implement .bdrv_co_pwritev_compressed() still (or they cannot forward compressed writes). Therefore, checking whether bs->drv->bdrv_co_pwritev_compressed is non-NULL is not sufficient to know whether the node can actually handle compressed writes. This function looks down the filter chain to see whether there is a non-filter that can actually convert the compressed writes into compressed data (and thus normal writes). Signed-off-by: Max Reitz Reviewed-by: Vladimir Sementsov-Ogievskiy --- include/block/block.h | 1 + block.c | 22 ++++++++++++++++++++++ 2 files changed, 23 insertions(+) diff --git a/include/block/block.h b/include/block/block.h index 9cfe77abaf..6ba853fb90 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -487,6 +487,7 @@ BlockDriverState *bdrv_next(BdrvNextIterator *it); void bdrv_next_cleanup(BdrvNextIterator *it); =20 BlockDriverState *bdrv_next_monitor_owned(BlockDriverState *bs); +bool bdrv_supports_compressed_writes(BlockDriverState *bs); void bdrv_iterate_format(void (*it)(void *opaque, const char *name), void *opaque, bool read_only); const char *bdrv_get_node_name(const BlockDriverState *bs); diff --git a/block.c b/block.c index 415c555bf5..029c809a8e 100644 --- a/block.c +++ b/block.c @@ -4696,6 +4696,28 @@ bool bdrv_is_sg(BlockDriverState *bs) return bs->sg; } =20 +/** + * Return whether the given node supports compressed writes. + */ +bool bdrv_supports_compressed_writes(BlockDriverState *bs) +{ + BlockDriverState *filtered =3D bdrv_filtered_rw_bs(bs); + + if (!bs->drv || !bs->drv->bdrv_co_pwritev_compressed) { + return false; + } + + if (filtered) { + /* + * Filters can only forward compressed writes, so we have to + * check the child. + */ + return bdrv_supports_compressed_writes(filtered); + } + + return true; +} + const char *bdrv_get_format_name(BlockDriverState *bs) { return bs->drv ? bs->drv->format_name : NULL; --=20 2.21.0