strange DF (disk full) output

[Roberto Spadim]

hello guys, i'm using archlinux current under XFS
see what's happen with my /dev/sda2 (/ root partition)
DF output: (88% Usage)

address@hidden /]# df
Sist. Arq.           1K-blocos      Usad Dispon.   Uso% Montado em
/dev/sda2              9765312   8567884   1197428  88% /
none                   1545756         0   1545756   0% /dev/shm
/dev/sda1               101086     14775     81092  16% /boot
/dev/md0              66275784  19522908  46752876  30% /home
//10.10.0.100/VOL_1   22932480  22372352    560128  98% /mnt/smb
none                   1545756         4   1545752   1% /tmp




DU output:

address@hidden /]# du -s -x /
2031605 /


DU output of all files of /:


address@hidden /]# du -s  /*
5076    /bin
9124    /boot
444     /dev
7820    /etc
19506348        /home
58184   /lib
0       /lib64
0       /lost+found
du: impossível acessar `/mnt/smb/como fazer ligaoes.rtf': Arquivo ou 
diretório não encontrado
21018815        /mnt
0       /opt
0       /proc
426256  /root
13144   /sbin
0       /srv
0       /sys
4       /tmp
844944  /usr
676172  /var





i think that DF is understanding /mnt/smb (smbfs mount point) as / disk 
usage
but if i umount it and get again df and du -s /*, df still with 88%

what could i do? i think that DU is right, but DF is the main problem 
since, if i do:
dd if=/dev/zero of=/test bs=1024 count=very big count
i get:

address@hidden /]# dd if=/dev/zero of=/test bs=1024 count=5000000000
rm /testdd: escrevendo `/test': Não há espaço disponível no dispositivo
1194693+0 records in
1194692+0 records out
1223364608 bytes (1,2 GB) copied, 37,6201 s, 32,5 MB/s



so, df is my problem since i have "only" 1.2 gb,

check /etc/fstab:
/dev/cdrom /mnt/cdrom  iso9660   ro,user,noauto,unhide   0      0
/dev/sda1  /boot       ext3      defaults 0 1
/dev/sda2  /           xfs       defaults 0 1
/dev/md0   /home       xfs       defaults 0 1
/dev/sda3  swap        swap      defaults 0 0
/dev/sdb3  swap        swap      defaults 0 0
//10.10.0.100/VOL_1     /mnt/smb smbfs 
defaults,username=spadim,password=spadim,uid=1000,fmask=777,dmask=777 0 0
none       /tmp        tmpfs     defaults 0 0



thankx
any help could be very good