Patrick schrieb:
> Patrick schrieb:
>> Patrick schrieb:
>>> Flemming Madsen schrieb:
>>>
>>>> Patrick wrote:
>>>>
>>>>> But isnt there another way? e.g. copying / mount-moving/binding
>>>>> real_root to the union or something like that?
>>>>>
>>>>>
>>>> The way i make access to the underlying filesystems is to 'mount -o
>>>> move' the underlying
>>>> mount point into the union berfore i chroot into it.
>>>>
>>>> In my setup i have in the flash:
>>>>
>>>> - A squashfs root filesystem to boot on
>>>> - A ram filesyatem to pickup writes
>>>> - A /flash to persist things
>>>> - The /flash/root directory for patching the squashfs root
>>>>
>>>> I have these in /mnt and move them into the union to have access to
>>>> the
>>>> underlying
>>>> filesystems after the chroot
>>>>
>>>> Sketchy: Eg. (with unionfs)
>>>>
>>>> mount /mnt/ram/
>>>> mount /mnt/flash/
>>>> mount / /mnt/initroot -o bind
>>>>
>>>> mount -t unionfs unionfs /mnt/union -o
>>>> dirs=/mnt/ram:/mnt/flash/root=ro:/mnt/initroot=ro
>>>>
>>>> mount /mnt/flash /mnt/union/mnt/flash -o move
>>>> mount /mnt/ram /mnt/union/mnt/ram -o move
>>>> mount /mnt/initroot /mnt/union/mnt/initroot -o move
>>>>
>>>> cd /mnt/union
>>>> chroot . init # Rock & roll
>>>>
>>> Heh, thats what I exactly tried myself .. but here it doesnt work .
>>> none of the mounted filesystems that were moved are accessable /
>>> viewable in the union later on.
>>>
>>>
>> heh okay, got that one fixed (added some sleep's and seen it was a
>> typo tho.. now my question is .. your /mnt/ram is tmpfs I guess while
>> /mnt/flash is where? like where is it actually stored? (only thing I
>> can imagine is onto the rootfs)
>>
> Hmm .. well I think I was wrong with that assumption .. seems as if
> your /flash is on another partition/device than the rootfs is ..
> otherwise it wouldnt work, would it since the rootfs is mounted ro ..
> enlighten me please!
>
Finally ... I reconfirmed my statement, that /flash cant be within the
actual rootfs .. (tried a loop device tho, and aufs moans about
overlapping) .. now I used a dedicated partition .. so it is like:
/new is a tmpfs and /real_root is the real rootfs .. now /flash is on
another partition and I mount the unionfs like mount -w -t aufs -o
dirs=/new=rw:/flash=ro:/real_root=ro aufs /union .. so when changing
something on the unified FS changes go to /new obviously .. and if I put
for instance /etc/fstab into /flash .. I can have persistent changes.
But that is not exactly what I wanted, so I thought of a method having
the rootfs under /flash too (so I can easily change files without
copying them + their appropiate dirs to /flash) .. Thus I introduced
another directory calld /change .. moved it to the unified fs (same with
/real_root) and now my init of initramfs looks like:
mkdir -p /real_root
mkdir -p /new
mkdir -p /change
mkdir -p /flash
mount -w -t aufs -o dirs=/new=rw:/flash=ro:/real_root=ro none /union
mkdir -p /union/mnt/new
mkdir -p /union/mnt/real_root
mkdir -p /union/mnt/flash
mkdir -p /union/mnt/change
mount -o move /new ${rootmnt}/mnt/new
mount -o move /real_root ${rootmnt}/mnt/real_root
mount -o move /flash ${rootmnt}/mnt/flash
mount -w -t aufs -o
dirs=${rootmnt}/mnt/flash=rw:${rootmnt}/mnt/real_root=ro aufs /change
mount -o move /change ${rootmnt}/mnt/change
Now to explain that: Once I want a persistent change ... I easily adapt
the files in /mnt/change .. so the changes go to /mnt/flash .. while
/mnt/flash is in hierachy higher than /real_root .. the changes are
persistent ...
I hope this may help other users who run in a similar kind of problem :-)
regards,
Patrick
> regards,
> Patrick
>
>>> regards,
>>> Patrick
>>>
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>>>
>>>
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>>
>>
>
>
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