Problem with quotas on 4.10

[Wolfi]

Hi,

I have following problem on a 4.10

I have "options QUOTA" enabled in kernel
In "/etc/rc.conf" enable_quotas="YES"


That's my "/etc/fstab"
/dev/da0s1b		none		swap    sw              0
0
/dev/da0s1a		/		ufs     rw              1
1
/dev/da0s1h		/data		ufs     rw,userquota,groupquota
2       2
/dev/da0s1f		/tmp		ufs     rw              2
2
/dev/da0s1g		/usr		ufs     rw              2
2
/dev/da0s1e		/var		ufs     rw              2
2
/dev/acd0c		/cdrom	cd9660  ro,noauto       0       0
proc			/proc		procfs  rw              0
0

I set quotas for a user "foo" to 100MB
then I copyied as root a file (2 MB)  in his directory (/data/foo)
the user is not over quotas! he has enough space left
and I would with "chown foo filename" change the owner of the file
but the command didn't finish.
I can nothing do in this directory (/data/foo)
if I try a (in another terminal) "ls -l /data/foo" the command hangs
i cannot kill the chown process
in "top" I see the the chown process with state "chkdq1"
I can't reboot the machine.
I must power off and then power on, that the problem is away.
I tryied the same on 5.3 and there it works well.

What I'm doing wrong?

Wolfgang