From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36211) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fiM9r-0004Ra-Ty for qemu-devel@nongnu.org; Wed, 25 Jul 2018 11:57:02 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fiM9p-00069S-0A for qemu-devel@nongnu.org; Wed, 25 Jul 2018 11:57:00 -0400 References: <20180725151011.25951-1-armbru@redhat.com> From: Eric Blake Message-ID: <5e713599-997f-7dda-917c-80902f6ef328@redhat.com> Date: Wed, 25 Jul 2018 10:56:48 -0500 MIME-Version: 1.0 In-Reply-To: <20180725151011.25951-1-armbru@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC PATCH] rbd: Don't convert keypairs to JSON and back List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Armbruster , qemu-devel@nongnu.org Cc: kwolf@redhat.com, jdurgin@redhat.com, jcody@redhat.com, qemu-block@nongnu.org, mreitz@redhat.com On 07/25/2018 10:10 AM, Markus Armbruster wrote: > qemu_rbd_parse_filename() builds a keypairs QList, converts it to JSON, and > stores the resulting QString in a QDict. > > qemu_rbd_co_create_opts() and qemu_rbd_open() get the QString from the > QDict, pass it to qemu_rbd_set_keypairs(), which converts it back into > a QList. > > Drop both conversions, store the QList instead. > > This affects output of qemu-img info. Before this patch: > > $ qemu-img info rbd:rbd/testimg.raw:mon_host=192.168.15.180:rbd_cache=true:conf=/tmp/ceph.conf > [junk printed by Ceph library code...] > image: json:{"driver": "raw", "file": {"pool": "rbd", "image": "testimg.raw", "conf": "/tmp/ceph.conf", "driver": "rbd", "=keyvalue-pairs": "[\"mon_host\", \"192.168.15.180\", \"rbd_cache\", \"true\"]"}} > [more output, not interesting here] > > After this patch, we get > > image: json:{"driver": "raw", "file": {"pool": "rbd", "image": "testimg.raw", "conf": "/tmp/ceph.conf", "driver": "rbd", "=keyvalue-pairs": ["mon_host", "192.168.15.180", "rbd_cache", "true"]}} > > The value of member "=keyvalue-pairs" changes from a string containing > a JSON array to that JSON array. That's an improvement of sorts. However: > > * Should "=keyvalue-pairs" even be visible here? It's supposed to be > purely internal... I'd argue that since it is supposed to be internal (as evidenced by the leading '=' that does not name a normal variable), changing it doesn't hurt stability. But yes, it would be nicer if we could filter it entirely so that it does not appear in json: output, if it doesn't truly affect the contents that the guest would see. > > * Is this a stable interface we need to preserve, warts and all? I hope not. > > Signed-off-by: Markus Armbruster > --- > block/rbd.c | 50 ++++++++++++++++++++++---------------------------- > 1 file changed, 22 insertions(+), 28 deletions(-) I'm not yet convinced if we want this patch for 3.0 without more comments from the RBD experts, nor do I see too much of an issue if this doesn't go in until 3.1. But as to the code changes itself, I find them nice. Reviewed-by: Eric Blake -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org