From patchwork Fri Dec 13 07:35:14 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fam Zheng X-Patchwork-Id: 300920 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)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id E26F82C00A1 for ; Fri, 13 Dec 2013 18:37:24 +1100 (EST) Received: from localhost ([::1]:40487 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VrNJK-0006DJ-8p for incoming@patchwork.ozlabs.org; Fri, 13 Dec 2013 02:37:22 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59876) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VrNIk-00060Y-No for qemu-devel@nongnu.org; Fri, 13 Dec 2013 02:36:52 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VrNId-0005i7-7O for qemu-devel@nongnu.org; Fri, 13 Dec 2013 02:36:46 -0500 Received: from mx1.redhat.com ([209.132.183.28]:60564) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VrNIc-0005hz-Vm for qemu-devel@nongnu.org; Fri, 13 Dec 2013 02:36:39 -0500 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id rBD7aB0P019822 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Fri, 13 Dec 2013 02:36:12 -0500 Received: from ad.nay.redhat.com ([10.66.6.190]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id rBD7ZUaJ010195; Fri, 13 Dec 2013 02:36:06 -0500 From: Fam Zheng To: qemu-devel@nongnu.org Date: Fri, 13 Dec 2013 15:35:14 +0800 Message-Id: <1386920120-2651-7-git-send-email-famz@redhat.com> In-Reply-To: <1386920120-2651-1-git-send-email-famz@redhat.com> References: <1386920120-2651-1-git-send-email-famz@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.11 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: kwolf@redhat.com, rjones@redhat.com, armbru@redhat.com, imain@redhat.com, stefanha@redhat.com, pbonzini@redhat.com Subject: [Qemu-devel] [PATCH v8 06/12] 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 | 29 +++++++++++++++++++++++------ include/block/block.h | 1 + 2 files changed, 24 insertions(+), 6 deletions(-) diff --git a/block.c b/block.c index 28814f7..63a5918 100644 --- a/block.c +++ b/block.c @@ -958,6 +958,24 @@ fail: return ret; } +void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd) +{ + if (bs->backing_hd) { + bdrv_unref(bs->backing_hd); + } + + bs->backing_hd = backing_hd; + if (!backing_hd) { + return; + } + bdrv_ref(bs->backing_hd); + + pstrcpy(bs->backing_file, sizeof(bs->backing_file), + bs->backing_hd->file->filename); + pstrcpy(bs->backing_format, sizeof(bs->backing_format), + bs->backing_hd->drv->format_name); +} + /* * Opens the backing file for a BlockDriverState if not yet open * @@ -971,6 +989,7 @@ 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) { @@ -994,7 +1013,7 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp) sizeof(backing_filename)); } - bs->backing_hd = bdrv_new(""); + backing_hd = bdrv_new(""); if (bs->backing_format[0] != '\0') { back_drv = bdrv_find_format(bs->backing_format); @@ -1004,20 +1023,18 @@ 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); - ret = bdrv_open(bs->backing_hd, + ret = bdrv_open(backing_hd, *backing_filename ? backing_filename : NULL, options, back_flags, back_drv, &local_err); if (ret < 0) { - bdrv_unref(bs->backing_hd); - bs->backing_hd = NULL; + bdrv_unref(backing_hd); 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; } - pstrcpy(bs->backing_file, sizeof(bs->backing_file), - bs->backing_hd->file->filename); + bdrv_set_backing_hd(bs, backing_hd); return 0; } diff --git a/include/block/block.h b/include/block/block.h index ac8976e..20bfcd9 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -185,6 +185,7 @@ int bdrv_parse_cache_flags(const char *mode, int *flags); int bdrv_parse_discard_flags(const char *mode, int *flags); int bdrv_file_open(BlockDriverState **pbs, const char *filename, QDict *options, int flags, 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 *bs, const char *filename, QDict *options, int flags, BlockDriver *drv, Error **errp);