Restarting nfs-kernel-server drops zfs shares

[atonkyra]

We need better integration with nfs-kernel-server for pools using zfs sharenfs. Currently for example restarting nfs-kernel-server causes the following to happen:

root@zorro:~# showmount -e
Export list for zorro:
root@zorro:~# zfs set sharenfs=on testpool/nfstest
root@zorro:~# showmount -e
Export list for zorro:
/testpool/nfstest *
root@zorro:~# mount -t nfs4 localhost:/testpool/nfstest /mnt/nfsloopbacktest
root@zorro:~# showmount -e
Export list for zorro:
/testpool/nfstest *
root@zorro:~# touch /testpool/nfstest/testfile
root@zorro:~# ls /mnt/nfsloopbacktest
testfile
root@zorro:~# dd if=/dev/zero of=/mnt/nfsloopbacktest/testfile bs=1M &
[1] 3536
root@zorro:~#
root@zorro:~# /etc/init.d/nfs-kernel-server restart
 * Stopping NFS kernel daemon                                                                                                 [ OK ]
 * Unexporting directories for NFS kernel daemon...                                                                           [ OK ]
 * Exporting directories for NFS kernel daemon...                                                                             [ OK ]
 * Starting NFS kernel daemon                                                                                                 [ OK ]
root@zorro:~#
root@zorro:~# showmount -e
Export list for zorro:
root@zorro:~# ps xua |grep dd
root         2  0.0  0.0      0     0 ?        S    19:22   0:00 [kthreadd]
root      3536  3.8  0.0  12516  1736 pts/0    D    19:34   0:01 dd if=/dev/zero of=/mnt/nfsloopbacktest/testfile bs=1M
root      3615  0.0  0.0   9444   952 pts/0    S+   19:34   0:00 grep --color=auto dd
root@zorro:~# ls /mnt/nfsloopbacktest
^C^Z
[[ WE ARE STUCK HERE, IN ANOTHER TERMINAL: ]]
root@zorro:~# zfs share -a
[[ BACK TO BUSINESS ]]

root@zorro:~#

@ryao mentioned zeventd might solve this in the future.

[behlendorf]

This may be difficult to implement. If you're restarting the NFS kernel server outside of ZFS then somehow ZFS will need to be notified that the filesystem must be shared again.

[rca]

I ran into this. For anyone else landing here:

sudo /bin/sh -c 'service nfs-kernel-sever restart && zfs share -a'