Re: UNS: Re: [Dazuko-devel] Fwd: Mounting DauzkoFS on root

[jim burns]

Thanx for your reply.

On Wed May 9 2007 2:29:32 pm John Ogness wrote:
> jim burns wrote:
> Yes, this is a known issue. The technical problems associated with this
> are briefly mentioned in the README under the section:
>
> "IMPORTANT - ALREADY RUNNING PROCESSES"
>
> Since the "init" process is started before DazukoFS is mounted and all
> subprocesses fork from "init", it is not possible to mount DazukoFS on
> "/" and expect file events to be detected. For this to happen, the
> DazukoFS mount would need to take place before "init" runs (which hasn't
> quite been worked out yet).

I assumed this meant I just need to make sure the mounts take place early in 
the boot process. Since mounts take place in /etc/init.d/boot.localfs (on 
SuSE), and the boot services run before any other services, the mounts take 
place before most processes are run. In fact, I do a 'ps -AH' in 
boot.localfs, and there are only 30 processes running just after the local 
filesystem mounts take place, and most of them are kthreads.

Refresh my unix system programming memory - just because 'init' has '/' open 
doesn't mean every proc forked off of 'init' has it open, does it? I assumed 
that any program started after the local filesystem mounts are done would be 
fully covered. If unix procs inherit open files from init, those 
files/filesystems can never be protected.

> > Oh, and I should say, when I try to mount DazukoFS, it doesn't echo
> > to /etc/mtab - only to /proc/mounts (openSuSE 10.2).
>
> I will look into this. DazukoFS is based on the FiST project, so perhaps
> they know more about this.

Just to be clear, this only happens if I try to mount '/'. It works fine for 
other files or subdirs.

I'm having varying success overlaying the subdirs and files under '/'. Do you 
recommend overlaying local filesystems like vfat, ntfs, fuse? Remote 
filesystem mount points? Special filesystems - proc, sysfs, debugfs, udev 
(/dev), devpts? I was not able to overlay /dev, /proc, /sys (major network 
problems); /sbin & /usr (causes some services to report failure, tho' the 
process is still running); /var (nfs problems); or any mount point or parent 
of a mount point. I also am having problems shutting down. I had to 
separate 'umount'-ing the dazukofs systems in boot.localfs, because they 
trigger an error path. I do 'umount -avt dazukofs', which segfaults (on /lib, 
I think), and then pass 'nodazukofs' to the normal 'umount' in boot.localfs.

Thank you for any guidance you can provide.