From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49276) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UwusJ-0004ht-Hd for qemu-devel@nongnu.org; Wed, 10 Jul 2013 09:56:08 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UwusH-0007Cl-HS for qemu-devel@nongnu.org; Wed, 10 Jul 2013 09:56:07 -0400 Received: from e23smtp04.au.ibm.com ([202.81.31.146]:59788) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UwusG-0007CI-Tu for qemu-devel@nongnu.org; Wed, 10 Jul 2013 09:56:05 -0400 Received: from /spool/local by e23smtp04.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 10 Jul 2013 23:40:51 +1000 Received: from d23relay04.au.ibm.com (d23relay04.au.ibm.com [9.190.234.120]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id 93BA42BB0051 for ; Wed, 10 Jul 2013 23:55:57 +1000 (EST) Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay04.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r6ADeoku44957724 for ; Wed, 10 Jul 2013 23:40:50 +1000 Received: from d23av02.au.ibm.com (loopback [127.0.0.1]) by d23av02.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r6ADtvFp012636 for ; Wed, 10 Jul 2013 23:55:57 +1000 Message-ID: <51DD67A2.6090806@linux.vnet.ibm.com> Date: Wed, 10 Jul 2013 21:54:42 +0800 From: Wenchao Xia MIME-Version: 1.0 References: <1373270451-18436-1-git-send-email-xiawenc@linux.vnet.ibm.com> <1373270451-18436-3-git-send-email-xiawenc@linux.vnet.ibm.com> <20130710131040.GO3898@dhcp-200-207.str.redhat.com> In-Reply-To: <20130710131040.GO3898@dhcp-200-207.str.redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH V4 2/9] snapshot: add paired functions for internal snapshot id and name List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf Cc: phrdina@redhat.com, famz@redhat.com, armbru@redhat.com, qemu-devel@nongnu.org, lcapitulino@redhat.com, stefanha@redhat.com, pbonzini@redhat.com, dietmar@proxmox.com 于 2013-7-10 21:10, Kevin Wolf 写道: > Am 08.07.2013 um 10:00 hat Wenchao Xia geschrieben: >> Internal snapshot's ID and name concept are both visible in general >> block level, they are observed by user in "info snapshots", so it is >> possible to have conflict. Although we can separate the two concept in >> programming, but if they can be distinguished in string itself, things >> will be simple and clear, so introduce two functions to do it. >> >> The implemention, qcow2 snapshot calls snapshot_id_string_generate() to >> make sure it follows the rule in driver. If caller or user give a check >> with snapshot_name_wellformed() before create snapshot, then the ID >> and name will never conflict. The check can be also taken in >> qcow2_snapshot_create(), but require it to return error reason. > > I'm not sure how useful this is. While we can restrict what IDs we allow > for creating new snapshots, we cannot take any advantage from it because > existing snapshots could already be named with only digits (they could > also use a non-numeric ID). At the end of the day we're limiting the Qcow2's ID seems always numeric, do you mean sheepdog may have non-numeric ID? > choice of IDs that can be generated with the QMP command without a real > reason. > This patch may limit the choice of snapshot name. Maybe we can't benefit from it now because existing code, but shouldn't it be improved in any new interface to alleviate the problem? I guess you idea is drop this check in the new interface, isn't it? > Kevin > -- Best Regards Wenchao Xia