Re: mount other than rootfs problem

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

On Fri, Sep 30, 2011 at 11:40:12AM +0800, Dave Young wrote:

[..]
> 
> Add lvm_scan in mount-sys.sh also works, so if we can make lvm_scan
> being called automaticlly via dependencies it will be good. OTOH fstab
> is better than cmdlines as an interface for multi-target dumping

Agreed that fstab.sys looks like a good interface to mouting non-root devices.

> 
> > 
> >> So If we properly deal with the dependency issue it should be possible
> >> to resolve. There's dracut module dependency currently, but question is
> >> that is there dependency of hooks? such as make the mount-sys hook
> >> depends on the lvm setup code, is it possible with current interface?
> >>
> > 
> > I don't think so, you called 'lvm_scan' and did mount manually, lvm
> > module itself will not mount it unless you add "rd_LVM_LV=". So, this
> > a not only a problem of module dependency, but also a problem
> > of lvm module code.
> 

lv_scan.sh seems to be parsing those rd_LVM_LV command line options to
come up with list of VGs and LVs to scan for. May be some script (probably
fstab-sys module) can leave some additional files in /tmp/ which lists
additional VGs and LVs to scan for. And this will be prepared by fstab-sys
module.

This is similar to lv_scan.sh reading /tmp/.lvm_scan-* files.

> 
> Yes, agree
> 
> >For kdump, even using "rd_LVM_LV=" is not a good
> > choice, because we still need to convert the device name (or UUID) into
> > the correct kernel cmdline.
> 
> 
> not understand yet, could you help to explain or give an example?

I think what he meant was that kdump.conf allows specifying UUID or LABEL
of the device to dump to. Assuming that these can directly be specified
in fstab.sys, or fstab-kdump.sys, then logic should be able to parse the
UUIDs, LABELs, and then traverse down the stack, figure out all the
dependencies.

Thanks
Vivek