smbd dumps core whed accessing manualy mounted fs

the same crash happens when .zfs directory for dataset is accessed through samba

I now understand this is not supported feature. I just needed to copy some data from ext3 disk, tried my experimental TrueNAS installation and found it was way too slow. Only later I found out that smbd crashed, so I submitted this ticket. If non zfs fs export is denied at vfs level, this should prevent any other users like me to cause smbd to crash, which is a good thing I think, that was the purpose of this ticket.

thanks for great piece of software guys!

But that said, we will not support exporting ext3/4 over SMB in SCALE.

As I mentioned this is a multi-step fix. First off is to actively discourage users from doing unsupported things. We do not support exporting ext3 filesystems over SMB.
The NULL deref and samba crash is fixed in the github PR against the samba repo for the vfs module that handles zfs integration. I'm somewhat inclined to simply assert in the module if we hit an FS that isn't ZFS because in general behavior will not be well-defined.

not sure if this patch prevents mentioned core dump. the error can be reproduced as follows:

1. share any VALID zfs dataset, for eample /mnt/pool_data/my_data

2. mkdir /mnt/pool_data/my_data/mnt

3. mount -t ext3 /dev/sdb1 /mnt/pool_data/my_data/mnt

4. access \\nas\my_data\mnt using windows explorer. core dumped.