* Passing information from initramfs to real rootfs
@ 2003-11-14 9:43 Hannes Reinecke
2003-11-14 9:47 ` Olaf Hering
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: Hannes Reinecke @ 2003-11-14 9:43 UTC (permalink / raw)
To: linux-hotplug
Hi all,
is it possible to get information out of initramfs to be passed to the
real root fs?
Currently initramfs is 'magically' mounted during boot, but vanished
equally magically as soon as the root device is mounted. Is there a way
planned/provided as to how information gathered/generated during the
boot process can be passed to the real root-fs?
I'm thinking especially on udev and friends; udev could handle
hotplug-events during boot-up from initramfs, but the devices generated
cannot be passed to the real root-device, so essentially we have to
re-scan sysfs to find and generate all events which might have been
generated during boot and pass them to udev _again_.
Nothing gained there; we can as well let it be handled entirely during
init as it is done now.
Easiest solution would be to have it moved initrd-style to /initramfs or
somesuch, then we could easily access it und umount it (i.e. free the
memory) as soon as we're done with the processing.
Comments? Enlightenments?
Cheers,
Hannes
--
Dr. Hannes Reinecke hare@suse.de
SuSE Linux AG S390 & zSeries
Deutschherrnstr. 15-19 +49 911 74053 688
90429 Nürnberg http://www.suse.de
-------------------------------------------------------
This SF.Net email sponsored by: ApacheCon 2003,
16-19 November in Las Vegas. Learn firsthand the latest
developments in Apache, PHP, Perl, XML, Java, MySQL,
WebDAV, and more! http://www.apachecon.com/
_______________________________________________
Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net
Linux-hotplug-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Passing information from initramfs to real rootfs
2003-11-14 9:43 Passing information from initramfs to real rootfs Hannes Reinecke
@ 2003-11-14 9:47 ` Olaf Hering
2003-11-14 17:42 ` Dave Dodge
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Olaf Hering @ 2003-11-14 9:47 UTC (permalink / raw)
To: linux-hotplug
On Fri, Nov 14, Hannes Reinecke wrote:
> Hi all,
>
> is it possible to get information out of initramfs to be passed to the
> real root fs?
mkdir /foo
mkfs.minix /dev/ram42
mount -nt minix /dev/ram42 /foo
echo my content > /foo/backup.txt
umount /foo
...
mount -n /dev/ram42 /oldinitramfscontent
might work.
--
USB is for mice, FireWire is for men!
sUse lINUX ag, n√úRNBERG
-------------------------------------------------------
This SF.Net email sponsored by: ApacheCon 2003,
16-19 November in Las Vegas. Learn firsthand the latest
developments in Apache, PHP, Perl, XML, Java, MySQL,
WebDAV, and more! http://www.apachecon.com/
_______________________________________________
Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net
Linux-hotplug-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Passing information from initramfs to real rootfs
2003-11-14 9:43 Passing information from initramfs to real rootfs Hannes Reinecke
2003-11-14 9:47 ` Olaf Hering
@ 2003-11-14 17:42 ` Dave Dodge
2003-11-14 18:44 ` Olaf Hering
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Dave Dodge @ 2003-11-14 17:42 UTC (permalink / raw)
To: linux-hotplug
On Fri, 14 Nov 2003, Hannes Reinecke wrote:
> I'm thinking especially on udev and friends; udev could handle
> hotplug-events during boot-up from initramfs, but the devices generated
> cannot be passed to the real root-device, so essentially we have to
> re-scan sysfs to find and generate all events which might have been
> generated during boot and pass them to udev _again_.
[...]
> Easiest solution would be to have it moved initrd-style to /initramfs or
> somesuch, then we could easily access it und umount it (i.e. free the
> memory) as soon as we're done with the processing.
That's what I was planning to do for my test system. With the current
kernel I basically have to eliminate mount_root anyway in order to
use initramfs at all, so I was going to do the "real" root mount in
userspace and pivot_root to it explicitly.
As far as the initramfs /dev, my plan is to try symlinking or bind
mounting it into the new root, and continue to use the same /dev as
initramfs. If you want to umount and free the initramfs memory then I
guess you'd have to copy the dev contents somehow (unless or until
someone has a way to create a dedicated ramfs for /dev during
initramfs and then remount that at /dev after a pivot_root).
-Dave Dodge
-------------------------------------------------------
This SF. Net email is sponsored by: GoToMyPC
GoToMyPC is the fast, easy and secure way to access your computer from
any Web browser or wireless device. Click here to Try it Free!
https://www.gotomypc.com/tr/OSDN/AW/Q4_2003/t/g22lp?Target=mm/g22lp.tmpl
_______________________________________________
Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net
Linux-hotplug-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Passing information from initramfs to real rootfs
2003-11-14 9:43 Passing information from initramfs to real rootfs Hannes Reinecke
2003-11-14 9:47 ` Olaf Hering
2003-11-14 17:42 ` Dave Dodge
@ 2003-11-14 18:44 ` Olaf Hering
2003-11-20 0:01 ` Greg KH
2003-11-20 6:41 ` Olaf Hering
4 siblings, 0 replies; 6+ messages in thread
From: Olaf Hering @ 2003-11-14 18:44 UTC (permalink / raw)
To: linux-hotplug
On Fri, Nov 14, Olaf Hering wrote:
> On Fri, Nov 14, Hannes Reinecke wrote:
>
> > Hi all,
> >
> > is it possible to get information out of initramfs to be passed to the
> > real root fs?
>
> mkdir /foo
> mkfs.minix /dev/ram42
> mount -nt minix /dev/ram42 /foo
> echo my content > /foo/backup.txt
> umount /foo
>
> ...
>
> mount -n /dev/ram42 /oldinitramfscontent
>
>
> might work.
Doesnt work, the ramdisk content disappears during umount. Does anyone
know what it disappears in the initramfs context, but not in the running
system?
--
USB is for mice, FireWire is for men!
sUse lINUX ag, n√úRNBERG
-------------------------------------------------------
This SF. Net email is sponsored by: GoToMyPC
GoToMyPC is the fast, easy and secure way to access your computer from
any Web browser or wireless device. Click here to Try it Free!
https://www.gotomypc.com/tr/OSDN/AW/Q4_2003/t/g22lp?Target=mm/g22lp.tmpl
_______________________________________________
Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net
Linux-hotplug-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Passing information from initramfs to real rootfs
2003-11-14 9:43 Passing information from initramfs to real rootfs Hannes Reinecke
` (2 preceding siblings ...)
2003-11-14 18:44 ` Olaf Hering
@ 2003-11-20 0:01 ` Greg KH
2003-11-20 6:41 ` Olaf Hering
4 siblings, 0 replies; 6+ messages in thread
From: Greg KH @ 2003-11-20 0:01 UTC (permalink / raw)
To: linux-hotplug
On Fri, Nov 14, 2003 at 07:44:09PM +0100, Olaf Hering wrote:
> On Fri, Nov 14, Olaf Hering wrote:
>
> > On Fri, Nov 14, Hannes Reinecke wrote:
> >
> > > Hi all,
> > >
> > > is it possible to get information out of initramfs to be passed to the
> > > real root fs?
> >
> > mkdir /foo
> > mkfs.minix /dev/ram42
> > mount -nt minix /dev/ram42 /foo
> > echo my content > /foo/backup.txt
> > umount /foo
> >
> > ...
> >
> > mount -n /dev/ram42 /oldinitramfscontent
> >
> >
> > might work.
>
> Doesnt work, the ramdisk content disappears during umount. Does anyone
> know what it disappears in the initramfs context, but not in the running
> system?
Why umount it then?
greg k-h
-------------------------------------------------------
This SF.net email is sponsored by: SF.net Giveback Program.
Does SourceForge.net help you be more productive? Does it
help you create better code? SHARE THE LOVE, and help us help
YOU! Click Here: http://sourceforge.net/donate/
_______________________________________________
Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net
Linux-hotplug-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Passing information from initramfs to real rootfs
2003-11-14 9:43 Passing information from initramfs to real rootfs Hannes Reinecke
` (3 preceding siblings ...)
2003-11-20 0:01 ` Greg KH
@ 2003-11-20 6:41 ` Olaf Hering
4 siblings, 0 replies; 6+ messages in thread
From: Olaf Hering @ 2003-11-20 6:41 UTC (permalink / raw)
To: linux-hotplug
On Wed, Nov 19, Greg KH wrote:
> On Fri, Nov 14, 2003 at 07:44:09PM +0100, Olaf Hering wrote:
> > On Fri, Nov 14, Olaf Hering wrote:
> >
> > > On Fri, Nov 14, Hannes Reinecke wrote:
> > >
> > > > Hi all,
> > > >
> > > > is it possible to get information out of initramfs to be passed to the
> > > > real root fs?
> > >
> > > mkdir /foo
> > > mkfs.minix /dev/ram42
> > > mount -nt minix /dev/ram42 /foo
> > > echo my content > /foo/backup.txt
> > > umount /foo
> > >
> > > ...
> > >
> > > mount -n /dev/ram42 /oldinitramfscontent
> > >
> > >
> > > might work.
> >
> > Doesnt work, the ramdisk content disappears during umount. Does anyone
> > know what it disappears in the initramfs context, but not in the running
> > system?
>
> Why umount it then?
/foo is in initramfs and not accessible after mounting the real root.
But there are ways to preserve the content somehow. It should not
disappear according to viro.
--
USB is for mice, FireWire is for men!
sUse lINUX ag, n√úRNBERG
-------------------------------------------------------
This SF.net email is sponsored by: SF.net Giveback Program.
Does SourceForge.net help you be more productive? Does it
help you create better code? SHARE THE LOVE, and help us help
YOU! Click Here: http://sourceforge.net/donate/
_______________________________________________
Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net
Linux-hotplug-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2003-11-20 6:41 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2003-11-14 9:43 Passing information from initramfs to real rootfs Hannes Reinecke
2003-11-14 9:47 ` Olaf Hering
2003-11-14 17:42 ` Dave Dodge
2003-11-14 18:44 ` Olaf Hering
2003-11-20 0:01 ` Greg KH
2003-11-20 6:41 ` Olaf Hering
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).