From mboxrd@z Thu Jan  1 00:00:00 1970
From: =?ISO-8859-1?Q?Stefan_Fr=F6berg?= <stefan.froberg@petroprogram.com>
Date: Fri, 25 Jan 2013 00:42:45 +0200
Subject: [Buildroot] Squashfs boot
In-Reply-To: <51017295.7020803@mind.be>
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24.1.2013 19:42, Arnout Vandecappelle kirjoitti:
> On 01/22/13 13:41, Stefan Fr?berg wrote:
> [snip]
>> My /etc/fstab look like this
>> # /etc/fstab: static file system information.
>> #
>> # <file system> <mount pt> <type> <options> <dump> <pass>
>> /modules.sqfs        /lib/modules    squashfs   
>> defaults,auto,loop,noatime    0    0
>> /firmware.sqfs      /lib/firmware    squashfs   
>> defaults,auto,loop,noatime    0    0
>> /dev/cdrom            /mnt/cdrom    iso9660      defaults,noatime   
>> 0    0
>> /mnt/cdrom/usr.sqfs        /mnt/ro        squashfs 
>> defaults,auto,loop,noatime    0    0
>
>  Now this is a real use case for being able to split the rootfs into
> several parts.
>
>  However, as Thomas mentioned, it's simpler to just use a complete
> squashfs rootfs and put the unionfs on top of that. How? Somewhere
> early in your init.d you put something like the following (a script I
> swiped from the internet, don't remember where from; I haven't
> actually tested it myself):
>
> #!/bin/sh
>
> CHROOT_PATH="/tmp/unionfs"
> UNION_OPT="-o
> allow_other,use_ino,suid,dev,nonempty,chroot=$CHROOT_PATH,max_files=32768"
>
> #mount -t proc proc /proc
> #mount -t tmpfs tmpfs /tmp
>
> mkdir -p $CHROOT_PATH/root
> mkdir -p $CHROOT_PATH/rw
> mkdir -p /tmp/union
>
> # Mount the filesystems
> mount --bind / $CHROOT_PATH/root
> # $CHROOT_PATH/rw is already on a tmpfs so doesn't need to be mounted
>
> modprobe fuse
> $CHROOT_PATH/root/usr/bin/unionfs $UNION_OPT /rw=RW:/root=RO /tmp/union
>
> #mount -t proc proc /tmp/union/proc
>
> cd /tmp/union
> mkdir oldroot
> pivot_root . oldroot
> cd /
>
> # Move existing mounts, if any
> #umount /proc
> mount --move /oldroot/proc /proc
> mount --move /oldroot/dev /dev
> mount --move /oldroot/sys /sys
> mount --move /oldroot/tmp /tmp
> rmdir /tmp/union
>

That looks very interesting Arnout.
If that works then I will own you a whiskey bottle :-)

Stefan