Strange effect of zfs rename

[Willem Jan Withagen]

Hoi,

In the process of creating backups I have this sequence of:

/sbin/zfs destroy   zfsraid/backups at Saturday-2
/sbin/zfs rename -f zfsraid/backups at Saturday zfsraid/backups at Saturday-2
/sbin/zfs snapshot  zfsraid/backups at Saturday

But then I end up with:
# cd /backups/.zfs/snapshot
# ll
ls: Saturday-2: Device busy
total 116
 0 dr-xr-xr-x  11 root  wheel  11 Aug  9 14:15 ./
 0 dr-xr-xr-x   4 root  wheel   4 Jul 30 22:07 ../
17 drwxr-xr-x  13 root  wheel  16 Jul 31 09:54 20140801/
17 drwxr-xr-x  18 root  wheel  21 Aug  5 01:03 Friday/
17 drwxr-xr-x  16 root  wheel  19 Aug  3 01:03 Monday/
17 drwxr-xr-x  15 root  wheel  18 Aug  2 01:03 Sunday/
17 drwxr-xr-x  18 root  wheel  21 Aug  5 01:03 Thursday/
17 drwxr-xr-x  17 root  wheel  20 Aug  4 01:03 Tuesday/
17 drwxr-xr-x  18 root  wheel  21 Aug  5 01:03 Wednesday/
Exit 1

And the device does not becomen not-busy even after a "long" wait.

The way to remedy this is:
/sbin/zfs unmount -f zfsraid/backups
/sbin/zfs mount      zfsraid/backups

After that the snapshot-dir is as it should.

I'm running:
FreeBSD zfs.digiware.nl 9.3-STABLE FreeBSD 9.3-STABLE #272 r269145M: Sun
Jul 27 06:50:06 CEST 2014
root at zfs.digiware.nl:/usr/obj/usr/srcs/src9/src/sys/ZFS  amd64

Can other reproduce this? Or is my system suffering from bitrot?

Regards,
--WjW