Strange effect of zfs rename

[Ronald Klop]

On Sat, 09 Aug 2014 14:41:42 +0200, Willem Jan Withagen <wjw at digiware.nl>  
wrote:

> 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

I don't see this. I used to work on 9-STABLE and now on 10-STABLE (from  
august 5th).

I use zfs rename a lot for handling my snapshots, but I do not use the -f  
option. I must say I never need to go into the .zfs/snapshot directories,  
so they are mounted seldom. I just went into them today for a test, but I  
don't have 'Device busy' problems. Do you keep such a directory active  
somewhere?

Ronald.