How to fill in the fsid for file systems?

[Rick Macklem]

Andriy Gapon wrote:
>On 31/10/2018 17:50, Rick Macklem wrote:
>> Andriy Gapon wrote:
>>> One is practical.  How do we provide fsid to ZFS filesystems?
>>> I mean I would hate to resort to mounting ZFS via fstab just to provide fsid
>>> whereas today ZFS filesystems are mounted auto-magically.
>>> We could add a FreeBSD specific fsid ZFS property, but that's also some extra code.
>> Good point. I'm not a ZFS guy, so I wouldn't have thought of this.
>
>A counter-point to my own point.  If we implement the fsid override in the
>common code, like vfs_do[n]mount, then we would not need to worry about any
>filesystem specifics.
Yes, and it would make the code easily MFC'able, since it avoids any changes to
struct export_args and mountd.c.

There probably is still an argument for rev'ing struct export_args (making
ex_flags 64bits so that the high order bits of mnt_flag don't get truncated)
and allowing the anonymous user to have more than 16 gids, but there would
be no rush nor a need to MFC this, I think?

I'll code up a generic "fsid=N" option and see what others think of the patch, rick