From patchwork Fri Mar 7 08:20:47 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fam Zheng X-Patchwork-Id: 327833 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 93CC22C009F for ; Fri, 7 Mar 2014 19:24:41 +1100 (EST) Received: from localhost ([::1]:35122 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WLq59-0004fW-4O for incoming@patchwork.ozlabs.org; Fri, 07 Mar 2014 03:24:39 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36567) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WLq1x-0007Cc-Hn for qemu-devel@nongnu.org; Fri, 07 Mar 2014 03:21:27 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WLq1q-0006nZ-Hr for qemu-devel@nongnu.org; Fri, 07 Mar 2014 03:21:21 -0500 Received: from mx1.redhat.com ([209.132.183.28]:17656) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WLq1q-0006nV-AB for qemu-devel@nongnu.org; Fri, 07 Mar 2014 03:21:14 -0500 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s278LCO4026110 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 7 Mar 2014 03:21:12 -0500 Received: from T430.nay.redhat.com ([10.66.6.152]) by int-mx12.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s278KfIt007439; Fri, 7 Mar 2014 03:21:08 -0500 From: Fam Zheng To: qemu-devel@nongnu.org Date: Fri, 7 Mar 2014 16:20:47 +0800 Message-Id: <1394180456-18139-6-git-send-email-famz@redhat.com> In-Reply-To: <1394180456-18139-1-git-send-email-famz@redhat.com> References: <1394180456-18139-1-git-send-email-famz@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.25 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: kwolf@redhat.com, benoit.canet@irqsave.net, rjones@redhat.com, jcody@redhat.com, armbru@redhat.com, ptoscano@redhat.com, imain@redhat.com, stefanha@redhat.com, pbonzini@redhat.com Subject: [Qemu-devel] [PATCH v16 05/14] block: Add bdrv_set_backing_hd() X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org This is the common but non-trivial steps to assign or change the backing_hd of BDS. Signed-off-by: Fam Zheng --- block.c | 39 +++++++++++++++++++++++++-------------- include/block/block.h | 1 + 2 files changed, 26 insertions(+), 14 deletions(-) diff --git a/block.c b/block.c index e7e759f..eaa3564 100644 --- a/block.c +++ b/block.c @@ -1042,6 +1042,23 @@ fail: return ret; } +void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd) +{ + + bs->backing_hd = backing_hd; + if (!backing_hd) { + bs->backing_file[0] = '\0'; + bs->backing_format[0] = '\0'; + goto out; + } + bs->open_flags &= ~BDRV_O_NO_BACKING; + pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_hd->filename); + pstrcpy(bs->backing_format, sizeof(bs->backing_format), + backing_hd->drv ? backing_hd->drv->format_name : ""); +out: + bdrv_refresh_limits(bs); +} + /* * Opens the backing file for a BlockDriverState if not yet open * @@ -1055,6 +1072,7 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp) char backing_filename[PATH_MAX]; int back_flags, ret; BlockDriver *back_drv = NULL; + BlockDriverState *backing_hd; Error *local_err = NULL; if (bs->backing_hd != NULL) { @@ -1078,6 +1096,8 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp) sizeof(backing_filename)); } + backing_hd = bdrv_new(""); + if (bs->backing_format[0] != '\0') { back_drv = bdrv_find_format(bs->backing_format); } @@ -1086,23 +1106,19 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp) back_flags = bs->open_flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_COPY_ON_READ); - assert(bs->backing_hd == NULL); - ret = bdrv_open(&bs->backing_hd, + ret = bdrv_open(&backing_hd, *backing_filename ? backing_filename : NULL, NULL, options, back_flags, back_drv, &local_err); if (ret < 0) { - bs->backing_hd = NULL; + bdrv_unref(backing_hd); + backing_hd = NULL; bs->open_flags |= BDRV_O_NO_BACKING; error_setg(errp, "Could not open backing file: %s", error_get_pretty(local_err)); error_free(local_err); return ret; } - - if (bs->backing_hd->file) { - pstrcpy(bs->backing_file, sizeof(bs->backing_file), - bs->backing_hd->file->filename); - } + bdrv_set_backing_hd(bs, backing_hd); /* Recalculate the BlockLimits with the backing file */ bdrv_refresh_limits(bs); @@ -1924,12 +1940,7 @@ void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top) /* The contents of 'tmp' will become bs_top, as we are * swapping bs_new and bs_top contents. */ - bs_top->backing_hd = bs_new; - bs_top->open_flags &= ~BDRV_O_NO_BACKING; - pstrcpy(bs_top->backing_file, sizeof(bs_top->backing_file), - bs_new->filename); - pstrcpy(bs_top->backing_format, sizeof(bs_top->backing_format), - bs_new->drv ? bs_new->drv->format_name : ""); + bdrv_set_backing_hd(bs_top, bs_new); } static void bdrv_delete(BlockDriverState *bs) diff --git a/include/block/block.h b/include/block/block.h index a46f70a..ee1582d 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -208,6 +208,7 @@ int bdrv_parse_discard_flags(const char *mode, int *flags); int bdrv_open_image(BlockDriverState **pbs, const char *filename, QDict *options, const char *bdref_key, int flags, bool allow_none, Error **errp); +void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd); int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp); int bdrv_open(BlockDriverState **pbs, const char *filename, const char *reference, QDict *options, int flags,