From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55022) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Uzgp0-0000zy-Dn for qemu-devel@nongnu.org; Thu, 18 Jul 2013 01:32:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Uzgox-0003Zf-UT for qemu-devel@nongnu.org; Thu, 18 Jul 2013 01:32:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:15159) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Uzgox-0003X5-Nh for qemu-devel@nongnu.org; Thu, 18 Jul 2013 01:32:07 -0400 Date: Thu, 18 Jul 2013 13:32:01 +0800 From: Fam Zheng Message-ID: <20130718053201.GG29052@T430s.nay.redhat.com> References: <1373881356-3294-1-git-send-email-cngesaint@gmail.com> <1373881356-3294-7-git-send-email-cngesaint@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1373881356-3294-7-git-send-email-cngesaint@gmail.com> Subject: Re: [Qemu-devel] [PATCH V3 6/7] block: Add backing file loop check in qcow2_change_backing_file() Reply-To: famz@redhat.com List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Xu Wang Cc: kwolf@redhat.com, stefanha@gmail.com, wdongxu@linux.vnet.ibm.com, qemu-devel@nongnu.org, xiawenc@linux.vnet.ibm.com On Mon, 07/15 05:42, Xu Wang wrote: > Add backing file loop check before execute change backing file for > qcow2 format. > > Signed-off-by: Xu Wang > --- > block/qcow2.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/block/qcow2.c b/block/qcow2.c > index 0eceefe..01bd7d5 100644 > --- a/block/qcow2.c > +++ b/block/qcow2.c > @@ -1195,6 +1195,12 @@ fail: > static int qcow2_change_backing_file(BlockDriverState *bs, > const char *backing_file, const char *backing_fmt) > { > + /* Check if loop exists in backing files chain after changed */ > + if (bdrv_backing_file_loop_check(bs->filename, > + bs->drv ? bs->drv->format_name : NULL, > + backing_file, backing_fmt)) { > + return -EIO; > + } > pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); > pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); > > -- > 1.8.1.4 > I'm not sure this is needed, there's already loop check in block layer's bdrv_change_backing_file(), which calls drv->bdrv_change_backing_file(). wouldn't this be redundant? Thanks. -- Fam