From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38547) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WmdAt-0005Vk-96 for qemu-devel@nongnu.org; Tue, 20 May 2014 02:05:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WmdAm-0001N4-Nk for qemu-devel@nongnu.org; Tue, 20 May 2014 02:05:19 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57839) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WmdAm-0001Mn-FF for qemu-devel@nongnu.org; Tue, 20 May 2014 02:05:12 -0400 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s4K65Bsc005239 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 20 May 2014 02:05:12 -0400 From: Fam Zheng Date: Tue, 20 May 2014 14:04:32 +0800 Message-Id: <1400565880-13409-8-git-send-email-famz@redhat.com> In-Reply-To: <1400565880-13409-1-git-send-email-famz@redhat.com> References: <1400565880-13409-1-git-send-email-famz@redhat.com> Subject: [Qemu-devel] [PATCH v20 07/15] block: Parse "backing" option to reference existing BDS List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, jcody@redhat.com, hbrock@redhat.com, rjones@redhat.com, armbru@redhat.com, imain@redhat.com, stefanha@redhat.com, pbonzini@redhat.com Now it's safe to allow reference for backing_hd in the interface. Signed-off-by: Fam Zheng --- block.c | 27 +++++++++++++++++++++++++-- 1 file changed, 25 insertions(+), 2 deletions(-) diff --git a/block.c b/block.c index efec10a..4fc2dd7 100644 --- a/block.c +++ b/block.c @@ -1445,12 +1445,35 @@ int bdrv_open(BlockDriverState **pbs, const char *filename, /* If there is a backing file, use it */ if ((flags & BDRV_O_NO_BACKING) == 0) { QDict *backing_options; + const char *backing_name; + BlockDriverState *backing_hd; + backing_name = qdict_get_try_str(options, "backing"); qdict_extract_subqdict(options, &backing_options, "backing."); - ret = bdrv_open_backing_file(bs, backing_options, &local_err); - if (ret < 0) { + + if (backing_name && qdict_size(backing_options)) { + error_setg(&local_err, + "Option \"backing\" and \"backing.*\" cannot be " + "used together"); + ret = -EINVAL; goto close_and_fail; } + if (backing_name) { + backing_hd = bdrv_find(backing_name); + if (!backing_hd) { + error_set(&local_err, QERR_DEVICE_NOT_FOUND, backing_name); + ret = -ENOENT; + goto close_and_fail; + } + qdict_del(options, "backing"); + bdrv_set_backing_hd(bs, backing_hd); + bdrv_ref(backing_hd); + } else { + ret = bdrv_open_backing_file(bs, backing_options, &local_err); + if (ret < 0) { + goto close_and_fail; + } + } } /* For snapshot=on, create a temporary qcow2 overlay. bs points to the -- 1.9.2