Bug#856337: systemd: please support kernel 4.4, or don't hardcode dm interface versions

[Marc Lehmann]

On Tue, Feb 28, 2017 at 10:11:10AM +0100, Christian Hofstaedtler <zeha at debian.org> wrote:
> > Alternatively, since lvm and dmsetup from stretch do not have any issues
> > with kernel 4.4, I suspect systemd hardcodes version numbers in direct
> > calls instead of going through e.g. libdevmapper - going through a library
> > such as libdevmapper that hanmdles the kernel versions bettrer would also
> > take care of this issue, at least for current stretch.
> 
> This is a direct result of the dm-ioctl.h header file shipped by the
> Linux kernel (and the linux-libc-dev package) - any program compiled
> against that official header file will embed the version number used
> to build. Building systemd (or anything else) against a newer kernel
> will result in this problem for older kernels.
> 
> libdevmapper works around this by embedding an old copy of
> dm-ioctl.h ...

Thanks for confirming my suspicion - would be a good reason to go through
libdevmapper, if only to be compatible with lvm2 and dmsetup and other
programs in stretch.

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