On 07/08/2010 08:49 PM, Gerardo Exequiel Pozzi wrote:
On 07/08/2010 04:51 AM, Thomas Bächler wrote:
Am 06.07.2010 20:02, schrieb Gerardo Exequiel Pozzi:
the other fix a directory that is unreacheable outside initramfs (is
not needed but fixed anyway).
There's something I've been meaning to do for a while, but my time is
very short recently. I'm telling you this, because I have the feeling if
I do, there'll be a patch for it tomorrow :)
hehe :P
I don't want to leave dangling mounts in initramfs that are invisible
from the system. This would involve the following:
1) Don't bind /bootmnt into the root, but mount --move it there.
2) Don't bind _mnt_bind file systems into the root, but also mount
--move (or mount them there directly)
Yes
3) After mounting, mount --move all aufs branches into a directory in
the root.
This way, nothing will be left in rootfs and invisible for us. I don't
know a good name for a directory, so I'll stick to /bootmnt. A layout
could be like:
/bootmnt/
/bootmnt/image (move the image here)
/bootmnt/isomounts
/bootmnt/isomounts/loop0 (move /mnt/loop0 here)
/bootmnt/isomounts/loop1
etc. What do you think?
If I understand corretly, please fix me if I am wrong, but.the problem
is that mounts will be overlapped(*) with aufs mount stack, so at
least one mountpoint must be unreacheable, this is where sqfs images
are mounted /tmpfs (and /tmpfs.sqfs if copytoram is used).
(*) http://bugs.archlinux.org/task/17182
"Aufs rejects the branch which is an ancestor or a descendant of
another branch. It is called overlapped. When the branch is
loopback-mounted directory, aufs also checks the source fs-image file
of loopback device. If the source file is a descendant of another
branch, it will be rejected too"
http://aufs.sourceforge.net/aufs2/man.html
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Currently this is what commands are executed on normal boot (mkdir
steps skipped)
1) mount -t tmpfs -o size=75%,mode=0755 tmpfs /tmpfs
2) mount -r -t udf /dev/disk/by-label/ARCH_201007 /bootmnt
3) mount -t aufs -o dirs=/tmpfs=rw none /new_root
4) mount -r -t squashfs /bootmnt/overlay.sqfs /tmpfs/mnt/overlay
5) mount -t aufs -o remount,append:/tmpfs/mnt/overlay=ro none /new_root
6) mount -r -t squashfs /bootmnt/root-image.sqfs /tmpfs/mnt/root-image
7) mount -t aufs -o remount,append:/tmpfs/mnt/root-image=ro none
/new_root
8) mount -o bind /bootmnt /new_root/bootmnt
What thing that may be improved here is:
* steps 4 and 6 instead of mounting on /tmpfs/mnt/imagename mount
under /mnt/imagename
currently an ls /new_root/mnt will display empty dirs "overlay" and
"root-image".
Now looks like a bit recursive.
* execute 3) then 2) so medium will me mounted directly to
/new_root/bootmnt
NO!, bind mount /bootmnt to /new_root/bootmnt should be keep...
otherwise on "shutdown", resourse or device busy message.
the same applies when copytoram
My hardcode archiso experiment: http://gist.github.com/468957 (I using
using initscript.git + my pending patch for rc.shutdown from
http://bugs.archlinux.org/task/19783)
Doing that dirs that will be unreachable are:
/tmpfs that is needed for aufs writeable branch, maybe can be renamed
to better named than tmpfs something like /rw_branch
/mnt/X where sqfs are mounted
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when copytoram=y (steps for mkdir and cp to /tmpfs.sqfs skipped)
1) mount -t tmpfs -o size=75%,mode=0755 tmpfs /tmpfs
2) mount -r -t udf /dev/disk/by-label/ARCH_201007 /bootmnt
3) mount -t aufs -o dirs=/tmpfs=rw none /new_root
4) mount -t tmpfs -o size=75%,mode=0755 tmpfs /tmpfs.sqfs
5) mount -r -t squashfs /tmpfs.sqfs/overlay.sqfs /tmpfs/mnt/overlay
6) mount -t aufs -o remount,append:/tmpfs/mnt/overlay=ro none /new_root
7) mount -r -t squashfs /tmpfs.sqfs/overlay.sqfs /tmpfs/mnt/overlay
8) mount -t aufs -o remount,append:/tmpfs/mnt/overlay=ro none /new_root
9) umount /bootmnt
Same commands except that sqfs images are mounted from /tmpfs.sqfs
directory on ram instead from /bootmnt (the boot medium)
- Same improvements here
- Same dirs unreachable plus /tmpfs.sqfs
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_mnt_bind function can be replaced with _mnt_move or removed, since
all things can be appended as aufs branch.
--
Gerardo Exequiel Pozzi
\cos^2\alpha + \sin^2\alpha = 1
