Re: [RFC PATCH 0/4] Adding useful information into swap partition header

[Karel Zak <kzak@redhat.com>]

On Tue, Oct 23, 2012 at 07:07:42PM +0530, Venkatraman S wrote:
> On 23 October 2012 17:46, Karel Zak <kzak@redhat.com> wrote:
> > On Mon, Oct 22, 2012 at 10:27:23PM +0530, Venkatraman S wrote:
> >> Venkatraman S (4):
> >>   libblkid/topology: add preferred_erase_size to topology probe
> >>   mkswap: refactor header preparation
> >>   mkswap: Add additional fields in swapheader
> >>   mkswap: Probe and embed useful block device info into swapheader
> >
> >  I don't see a problem to support additional information in the swap
> >  header, but our rule is pretty simple: first in Linus' tree, after
> >  that in userspace.
> >
> 
> Thanks Karl - that's understood. I posted the patches to better explain the
> issue I faced - this new parameter I introduced in topology.c is accessible
> only when I pass the root disk dev node to mkswap (as /dev/mmcblkX)
> and not when invoked with /dev/mmcblkXpY) (i.e a partition with the device).

 Well, the problem is that sysfs_{open,stat}() functions in
 lib/sysfs.c reads attributes from parent only for "queue/" directory
 attributes. It's trivial to fix this problem.

> So how should the topology probe be invoked in this case ?

 The question is if we really need to extend libblkid if the attribute
 is necessary only for mkswap.

 I think it would be better to read the sysfs attribute directly in
 mkswap (by lib/sysfs.c functions). The result will be one small patch
 for mkswap.

 Anyway, all this is trivial and maybe implemented very quickly --
 what we need is to have support in kernel.

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com