From patchwork Tue Jul 11 16:37:45 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Manos Pitsidianakis X-Patchwork-Id: 9835335 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 2790160363 for ; Tue, 11 Jul 2017 17:29:23 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0AB2C26E74 for ; Tue, 11 Jul 2017 17:29:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id F242B284AF; Tue, 11 Jul 2017 17:29:22 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 6017326E74 for ; Tue, 11 Jul 2017 17:29:22 +0000 (UTC) Received: from localhost ([::1]:47852 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dUyyP-0005zv-Jm for patchwork-qemu-devel@patchwork.kernel.org; Tue, 11 Jul 2017 13:29:21 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55926) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dUyCN-0001h5-5d for qemu-devel@nongnu.org; Tue, 11 Jul 2017 12:39:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dUyCM-00035z-35 for qemu-devel@nongnu.org; Tue, 11 Jul 2017 12:39:43 -0400 Received: from smtp1.ntua.gr ([147.102.222.183]:20882) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dUyCH-00034g-8W; Tue, 11 Jul 2017 12:39:37 -0400 Received: from mail.ntua.gr (ppp046176127036.access.hol.gr [46.176.127.36]) (authenticated bits=0) by smtp1.ntua.gr (8.15.2/8.15.2) with ESMTPSA id v6BGcGIs070839 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 11 Jul 2017 19:38:16 +0300 (EEST) (envelope-from el13635@mail.ntua.gr) X-Authentication-Warning: smtp1.ntua.gr: Host ppp046176127036.access.hol.gr [46.176.127.36] claimed to be mail.ntua.gr From: Manos Pitsidianakis To: qemu-devel Date: Tue, 11 Jul 2017 19:37:45 +0300 Message-Id: <20170711163748.17817-2-el13635@mail.ntua.gr> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170711163748.17817-1-el13635@mail.ntua.gr> References: <20170711163748.17817-1-el13635@mail.ntua.gr> X-detected-operating-system: by eggs.gnu.org: FreeBSD 9.x [fuzzy] X-Received-From: 147.102.222.183 Subject: [Qemu-devel] [PATCH v4 1/4] block: pass bdrv_* methods to bs->file by default in block filters X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Alberto Garcia , qemu-block , Max Reitz , Stefan Hajnoczi Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP The following functions fail if bs->drv is a filter and does not implement them: bdrv_probe_blocksizes bdrv_probe_geometry bdrv_truncate bdrv_has_zero_init bdrv_get_info Instead, the call should be passed to bs->file if it exists, to allow filter drivers to support those methods without implementing them. This commit makes `drv->is_filter = true` imply that these callbacks will be forwarded to bs->file by default, so disabling support for these functions must be done explicitly. Signed-off-by: Manos Pitsidianakis Reviewed-by: Eric Blake Reviewed-by: Stefan Hajnoczi --- block.c | 21 +++++++++++++++++++-- include/block/block_int.h | 6 +++++- 2 files changed, 24 insertions(+), 3 deletions(-) diff --git a/block.c b/block.c index 69439628..7f7530b6 100644 --- a/block.c +++ b/block.c @@ -494,6 +494,8 @@ int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz) if (drv && drv->bdrv_probe_blocksizes) { return drv->bdrv_probe_blocksizes(bs, bsz); + } else if (drv && drv->is_filter && bs->file) { + return bdrv_probe_blocksizes(bs->file->bs, bsz); } return -ENOTSUP; @@ -511,6 +513,8 @@ int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo) if (drv && drv->bdrv_probe_geometry) { return drv->bdrv_probe_geometry(bs, geo); + } else if (drv && drv->is_filter && bs->file) { + return bdrv_probe_geometry(bs->file->bs, geo); } return -ENOTSUP; @@ -3406,11 +3410,15 @@ int bdrv_truncate(BdrvChild *child, int64_t offset, Error **errp) assert(child->perm & BLK_PERM_RESIZE); + /* if bs->drv == NULL, bs is closed, so there's nothing to do here */ if (!drv) { error_setg(errp, "No medium inserted"); return -ENOMEDIUM; } if (!drv->bdrv_truncate) { + if (bs->file && drv->is_filter) { + return bdrv_truncate(bs->file, offset, errp); + } error_setg(errp, "Image format driver does not support resize"); return -ENOTSUP; } @@ -3778,6 +3786,9 @@ int bdrv_has_zero_init(BlockDriverState *bs) if (bs->drv->bdrv_has_zero_init) { return bs->drv->bdrv_has_zero_init(bs); } + if (bs->file && bs->drv->is_filter) { + return bdrv_has_zero_init(bs->file->bs); + } /* safe default */ return 0; @@ -3832,10 +3843,16 @@ void bdrv_get_backing_filename(BlockDriverState *bs, int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) { BlockDriver *drv = bs->drv; - if (!drv) + /* if bs->drv == NULL, bs is closed, so there's nothing to do here */ + if (!drv) { return -ENOMEDIUM; - if (!drv->bdrv_get_info) + } + if (!drv->bdrv_get_info) { + if (bs->file && drv->is_filter) { + return bdrv_get_info(bs->file->bs, bdi); + } return -ENOTSUP; + } memset(bdi, 0, sizeof(*bdi)); return drv->bdrv_get_info(bs, bdi); } diff --git a/include/block/block_int.h b/include/block/block_int.h index 15fa6021..75e93f72 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -87,7 +87,11 @@ struct BlockDriver { const char *format_name; int instance_size; - /* set to true if the BlockDriver is a block filter */ + /* set to true if the BlockDriver is a block filter. Block filters pass + * certain callbacks that refer to data (see block.c) to their bs->file if + * the driver doesn't implement them. Drivers that do not wish to forward + * must implement them and return -ENOTSUP. + */ bool is_filter; /* for snapshots block filter like Quorum can implement the * following recursive callback.