mount_newnfs & mount_nullfs problem.

[George Mamalakis]

Dear all,

In short:
If I export the filesystem /export/homes, and mount it through nfsv4 on 
a fbsd8-stable box in the folder /mnt, and then use mount_nullfs /mnt/ 
/path1/path2/path3, then I have the following-wrong behaviour. If I use 
vi /path1/path2/path3/mamalos/newfile to write a file, the file is saved 
in /path1/path2, instead (!!?!). Which is on my local filesystem tree. 
If I echo "mytestfile" > /path1/path2/path3/mamalos/one, then the file 
is correctly written in /path1/path2/path3/mamalos/one.

In my jail environment, I use a similar approach to that of 
freebsd-handbook for application jails (paragraph 15.6).

So in my setup, mount command shows:

solaris:/export/homes on /mnt (newnfs)
/jails/j/mroot on /jails/j/postfix (nullfs, local, read-only)
/jails/s/postfix on /jails/j/postfix/s (nullfs, local, read-only)
/jails/t/postfix on /jails/j/postfix/t (nullfs, local)
/mnt on /jails/j/postfix/t/home (nullfs)

where we see my imported filesystem, the path where my postfix jail 
starts (/jails/j/postfix) along with two other filesystems mounted on it 
(/jails/j/postfix/s and /jails/j/postfix/t). On top of the latter's 
folder "home" I mount /mnt.

If I jexec to that jail, and try to create a file using vi, then vi 
/home/mamalos/myfile is written in /jails/t/postfix (which is the same 
as /jails/j/postfix/t)

What I suspect is that there must be a problem with nfs4 root-directory  
(which is two subfolders deep -> /export/homes) and mount_nullfs. The 
thing is that information is finally stored in my local filesystem 
instead of the imported one, which is very strange...

I will look to it more thoroughly, so as to provide more feedback about 
the issue. Hopefully, someone with more knowledge on the source code 
will find an answer.

FBSD-box:
# uname -a
FreeBSD fbsd 8.0-STABLE FreeBSD 8.0-STABLE #2: Fri Feb 19 19:30:00 EET 
2010     root at filesrv.ee.auth.gr:/usr/obj/usr/src/sys/MYKERNEL  amd64
# mount_newnfs -o nfsv4,rw solaris:/export/homes /mnt/

OpenSolaris:
# uname -a
SunOS opensolaris 5.11 snv_111b i86pc i386 i86pc Solaris
# share -F nfs -o sec=sys,rw,root=@192.168.100.12 /export/homes 
192.168.100.12

where 192.168.100.12 is fbsd-box's IP.

Thank you all.

-- 
George Mamalakis

IT Officer
Electrical and Computer Engineer (Aristotle Un. of Thessaloniki),
MSc (Imperial College of London)

Department of Electrical and Computer Engineering
Faculty of Engineering
Aristotle University of Thessaloniki

phone number : +30 (2310) 994379