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Re: [Qemu-devel] [RFC PATCH] rbd: Don't convert keypairs to JSON and bac
From: |
Jeff Cody |
Subject: |
Re: [Qemu-devel] [RFC PATCH] rbd: Don't convert keypairs to JSON and back |
Date: |
Sat, 28 Jul 2018 00:23:08 -0400 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Wed, Jul 25, 2018 at 10:56:48AM -0500, Eric Blake wrote:
> 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 <address@hidden>
> >---
> > 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.
Based on my IRC discussions with Markus, I believe the target for this patch
is indeed 3.1, not 3.0.
>
> Reviewed-by: Eric Blake <address@hidden>
>
> --
> Eric Blake, Principal Software Engineer
> Red Hat, Inc. +1-919-301-3266
> Virtualization: qemu.org | libvirt.org
>