Re: [Xen-devel] blktap2 header consistency between userspace and kernel space

[Sylvain Munaut <s.munaut@xxxxxxxxxxxxxxxxxxxx>]

Hi,

Thanks for the explanation, it's indeed confusing :p


>         - blktap2: it's in Xen hypervisor sources, so the latest version is 
> in xen-unstable (xen.git master branch).
>
>         - blktap2.5: This is a blktap2 fork (and most "recent" version with 
> additional features) that's being used in XenServer/XCP and with xapi 
> toolstack in general: https://github.com/xen-org/blktap .

I based my RBD driver on that github code, so I guess I use blktap2.5
then. And you can see the header here :

https://raw.github.com/xen-org/blktap/master/drivers/linux-blktap.h


>         - blktap2.5: These drivers can be found from XenServer/XCP 2.6.32 
> classic xenlinux dom0 kernel trees, and also from dstodden's (now abandoned) 
> git repo at 
> http://xenbits.xen.org/gitweb/?p=people/dstodden/linux.git;a=summary and 
> http://xenbits.xen.org/gitweb/?p=people/dstodden/blktap-dkms.git;a=summary . 
> dstodden switched jobs, so those are unmaintained repos. CentOS6 Linux 3.4 
> Xen dom0 kernel also has the blktap2.5 patches/drivers included.

And if you look at the header in those tree :

http://xenbits.xen.org/gitweb/?p=people/dstodden/linux.git;a=blob;f=include/linux/blktap.h;h=2cbefe97a4ab191dab5aae3d65df611ec9d9d557;hb=blktap/next-2.6.39

You can see they don't match the userspace either.

The kernel blktap also seems to have FLUSH and TRIM support which are
not supported in any blktap userspace I could find.


> And then the good news: blktap3 is in the works, see patches on xen-devel 
> mailinglist, and it won't need any blktap kernel driver! It's purely an 
> userspace solution, with an active maintainer/developer.

Yes, I've seen :)  But it's probably going to be a while until it's in debian :p
But at least the drivers should be compatible with the one I wrote for blktap2.5

Cheers,

    Sylvain

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel