Re: [PATCH] Add option to bring up a device in initramfs

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

On Tue, Aug 14, 2012 at 02:27:27PM +0800, Dave Young wrote:
> On 08/13/2012 11:10 PM, Vivek Goyal wrote:
> 
> > On Thu, Aug 09, 2012 at 11:08:48AM +0800, Dave Young wrote:
> >>
> >> Kdump support dump to raw device which could be on top of complex storage
> >> such as multipath and iscsi which are standalone dracut modules.
> >>
> >> Add a --device option to dracut which will add the device to host_devs so
> >> dracut can add the dependent modules automaticlly and enable them in initramfs.
> >>
> > 
> > You have not specified any format for --device argument? What do you expect
> > there? Device name, UUID, udev persistent link, or what?
> 
> 
> It's a device name, should metion it in doc as well.
> 
> > 
> > Secondly, do we need some extra code to make sure somebody waits for
> > this device to come up? Who makes sure that initqueue does not exit
> > till this device node comes up.
> 
> 
> I see there's a wait-mount-dev.sh in 95fstab-sys module which is for
> waiting for the mount needed dev.
> 
> Currently dracut maintains host_devs and host_fs_types, host_fs_types
> are mainly used inst the fs kernel modules. Other than the filesystem
> modules we should use host_devs instead, ie. introduce
> for_each_host_devs for modules such as multipath and iscsi using.

I see that iscsi is using for_each_host_dev_fs, which has both device
and filesystem info. Same is the case with multipath.

May be add raw device in host_dev_fs with filesystem type as "raw" and
special case "raw" whoever relies on this info. There might be other
better ways to handle this though.

Thanks
Vivek