We need to be able to parse the 'filename' option for both rbd and iscsi,
because there may exist images in the wild that have json backing files,
that specify the filename argument.

Marking the series as RFC at least partially for the precedence given to
arguments; as written, these patches will give preference to the 'filename'
parameter over passed options.

Jeff Cody (2):
  block/rbd: enable filename option and parsing
  block/iscsi: enable filename option and parsing

 block/iscsi.c | 19 ++++++++++++++++++-
 block/rbd.c   | 19 ++++++++++++++++++-
 2 files changed, 36 insertions(+), 2 deletions(-)

-- 
2.9.3

On Mon, Jun 12, 2017 at 12:05:12AM -0400, Jeff Cody wrote:
> We need to be able to parse the 'filename' option for both rbd and iscsi,
> because there may exist images in the wild that have json backing files,
> that specify the filename argument.
> 
> Marking the series as RFC at least partially for the precedence given to
> arguments; as written, these patches will give preference to the 'filename'
> parameter over passed options.

I tested this as follows:

(1) Prepare a test image.  By using the ‘qemu-img rebase -u’ option we
can set the formerly correct / now incorrect backing option to an
arbitrary json string of our choosing:

$ qemu-img create test.img -f qcow2 10M
$ qemu-img rebase -u -b 'json:{"file.driver":"rbd","file.filename":"rbd:rbd/rbd.img:mon_host=127.0.0.0"}' test.img 

(2) With upstream qemu:

$ qemu-system-x86_64 -hda test.img 
qemu-system-x86_64: -hda test.img: Could not open backing file: Parameters 'pool' and 'image' are required

(3) With upstream qemu + these two patches:

$ ~/d/qemu/x86_64-softmmu/qemu-system-x86_64 -hda test.img
[hangs and eventually reports a timeout because I don't really
have a Ceph server]

So I would say that these patches, superficially at least, do seem to
work.  Although I wasn't able to test them against a real Ceph server.

  Tested-by: Richard W.M. Jones <rjones@redhat.com>

Rich.

-- 
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