Re: any idea about auto export multiple btrfs snapshots?

Frank Filz
2021-06-22T17:34:41Z

On 6/21/21 3:41 PM, Wang Yugui wrote:
> Hi,
>
>> OK thanks for the information. I think they will just work in nfs-ganesha as
>> long as the snapshots or subvols are mounted within an nfs-ganesha export or
>> are exported explicitly. nfs-ganesha has the equivalent of knfsd's
>> nohide/crossmnt options and when nfs-ganesha detects crossing a filesystem
>> boundary will lookup the filesystem via getmntend and listing btrfs subvols
>> and then expose that filesystem (via the fsid attribute) to the clients
>> where at least the Linux nfs client will detect a filesystem boundary and
>> create a new mount entry for it.
>
> Not only exported explicitly, but also kept in the same hierarchy.
>
> If we export
> /mnt/test #the btrfs
> /mnt/test/sub1 # the btrfs subvol 1
> /mnt/test/sub2 # the btrfs subvol 2
>
> we need to make sure we will not access '/mnt/test/sub1' through '/mnt/test'
> from nfs client.
>
> current safe export:
> #/mnt/test #the btrfs, not exported
> /mnt/test/sub1 # the btrfs subvol 1
> /mnt/test/sub2 # the btrfs subvol 2
>

What's the problem with exporting /mnt/test AND then exporting sub1 and
sub2 as crossmnt exports? As far as I can tell, that seems to work just
fine with nfs-ganesha.

Frank