Re: blueprint: consistency groups

[Mykola Golub <to.my.trociny@gmail.com>]

On Mon, May 02, 2016 at 05:26:04PM -0700, Victor Denisov wrote:
> I have a question regarding the implementation of list images in a
> consistency group.
> For referencing images I use their ids and pool ids, since image's
> name and pool's name are subject to change.
> In order to list the images in a consistency group I have a function:
> cg_list_images.
> This function only returns ids and pool ids.
> I presume normally users would like to see names instead of ids.
> Everything in rbd class is written the way that it accepts ioctx.
> Which is a handle for accessing pool.
> It means(in my opinion) that everything in rbd class should accept
> ioctx. As such, I can't open another ioctx when I'm already inside rbd
> class.
> It leaves me no choice, but to implement image's name resolution in
> tools/rbd/action/ConsGrp.cc.
> In this case only command line users can have images' names, but not
> other services that use librbd library.
> Is it fine?

You need to add RBD API functions. These functions operate only with
image names (image ID is unknown entity for RBD API). And use these
functions in tools/rbd/action/ConsGrp.cc. See for example the recently
added rbd_mirror_image_status_list(). Internally it uses
cls_client::mirror_image_status_list(), which returns image IDs; the
list is converted to image names, when returning to the user.

-- 
Mykola Golub