Re: [PATCH] rbd: replace the rbd sysfs interface

[Greg KH]

On Mon, Nov 22, 2010 at 04:45:31PM -0800, Sage Weil wrote:
> Hi Greg,
> 
> On Mon, 22 Nov 2010, Greg KH wrote:
> > On Mon, Nov 22, 2010 at 03:33:07PM -0800, Yehuda Sadeh wrote:
> > > 
> > > 
> > > On Fri, Nov 19, 2010 at 12:42 PM, Yehuda Sadeh Weinraub <yehuda@xxxxxxxxxxxxxxx> wrote:
> > > > One solution would be to create kobjects for (3) and for (4), without
> > > > using a group name. Another way, we can create groups for (2), and (3)
> > > > under (1), but that's about it, you can't create the snap specific
> > > > directory this way without resorting to some internal sysfs directory
> > > > creation, which will be horribly wrong. At that point we don't have
> > > > anything for 'snaps', and we don't really need to do any operations
> > > > under that directory, we just need it to exist so that it contains the
> > > > snapshot-specific directories.
> > > >
> > > > Another way would be to create a group for (2) under (1) and create a
> > > > kobject for (3), for which you can create group per snapshot.
> > > >
> > > > Am I missing something? We already have the first solution (kobjects
> > > > only) implemented, is there some real benefit for using the third
> > > > method? We'll have to manually add remove groups anyway, as snapshots
> > > > can be removed and new snapshots can be added.
> > > >
> > > 
> > > And following is the implementation for the first solution. It has a device
> > > for the rbd_dev, a kobject for the top snapshot directory and a kobject per
> > > snapshot. Please let me know if there's any issue with this implementation.
> > > We'd like to get this fixed for 2.6.37 and considering the large patch,
> > > it'd be nice getting an ack for it.
> > 
> > It's way too late for .37, as this is new stuff, right?
> 
> Well, that's the problem.  The current sysfs interface was based on 
> osdblk's.  That part didn't come up during review, and I wasn't aware that 
> the sysfs interface should get an explicit ack from you.  After RBD was 
> merged in 2.6.37-rc1 I saw part of the SCST sysfs thread and realized the 
> current interface was problematic, and we've been trying to work out how 
> to fix it ever since.
> 
> As things stand, we can either
>  1- wait, get an osdblk-like interface in 2.6.37, and change it later (a 
>     big fat no-no, as I understand things!)
>  2- get an improved sysfs interface sorted out and push to Linus ASAP (my 
>     preference)
>  3- have Linus revert RBD altogether :(
> 
> I'm hoping for #2, but we may need a bit more help from you unfortunately!  

How about:
	4- make the code depend on CONFIG_BROKEN and get it working for
	.38?

thanks,

greg k-h
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