Weird comportment when deleting files

Hi all,

when trying to delete files, it seems that it's not take in account 
immediatly by the system. Here is the result when I execute 'df -k' :
Filesystem  1K-blocks    Used   Avail Capacity  Mounted on
/dev/ad0s1a    254063  100153  133585    43%    /
/dev/ad0s1d    254063    5888  227850     3%    /var
/dev/ad0s1e    254063    5762  227976     2%    /tmp
/dev/ad0s1f   8322444 3278224 4378428    43%    /usr
/dev/ad0s1g   4626308 4399268 -143064   103%    /home
procfs              4       4       0   100%    /proc

Creating new files after then works : there's available space indeed in 
/home but df doesn't see it. Calling "sync" doesn't change anything.

One minute later aproximatly, all worked fine : df gave
Filesystem  1K-blocks    Used   Avail Capacity  Mounted on
/dev/ad0s1a    254063  101066  132672    43%    /
/dev/ad0s1d    254063    5888  227850     3%    /var
/dev/ad0s1e    254063    5762  227976     2%    /tmp
/dev/ad0s1f   8322444 3278224 4378428    43%    /usr
/dev/ad0s1g   4626308 3703136  553068    87%    /home
procfs              4       4       0   100%    /proc


Here is my system configuration :
DragonFly tanalahy 1.1-CURRENT DragonFly 1.1-CURRENT #0: Tue Oct 26 
02:42:27 CEST 2004     root@tanalahy:/usr/obj/usr/src/sys/GENERIC  i386

The kernel was compiled with gcc 2.95.

Romain