Re: Firmware assisted dump support in dracut

[Vivek Goyal <vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On Tue, Jun 04, 2013 at 01:50:19PM +0530, Mahesh Jagannath Salgaonkar wrote:
> On 05/30/2013 07:53 PM, Vivek Goyal wrote:
> > On Thu, May 30, 2013 at 08:49:07AM +0200, Harald Hoyer wrote:
> > 
> > [..]
> >>> Sorry for restarting this discussion very late. I would like to know how
> >>> safe is to rebuild kernel's default (boot) initramfs for an already
> >>> installed kernel ?
> >>>
> >>> Also, Does dracut provides any of following mechanism?
> >>> a) Mechanism where dracut can detect what options were used during first
> >>> build for a given (exsisting) initramfs. (This mechanism may help one to
> >>> regenerate similar initramfs with additional dracut modules.)
> >>
> >> currently dracut only stores which modules were used to generate the image in
> >> usr/lib/dracut/modules.txt
> >>
> >> But yes, you are right. Would be nice to save all the options and have a
> >> mechanism to regenerate it with those.
> >>
> > 
> > I am not sure how well it will work in the context of kdump.  kdump
> > options and original options might conflict. kdump might drop some of
> > its own cmdline options in initramfs which might not make any sense
> > in regular boot.
> > 
> > Kdump will specify additional mount points. IIUC, then we will try
> > to bring up those targets in regular boot too and mount at user
> > specified mount point. And later init services might get confused
> > when respective daemon tries to bring up same targets again.
> 
> I think we should be able differentiate between regular boot and boot
> after crash by checking existence of '/proc/vmcore' file, and do the
> kdump specific configs/mount if this file exists. In regular boot we can
> mute the kdump code path.

dracut takes --mount option and that option doesn not differentiate
between environment.

One can always create new options to mount certain things only in
kdump environment. I am not sure how much sense does it make to try
to special case everything related to kdump in dracut.

Thanks
Vivek