exports.5: Clarify that exported dirs should be local mount points

[emaste]

Should we mention something about ZFS here? I guess there should be a high-level section on ZFS/NFS that has a xref to wherever the sharenfs property is documented, and we could have an internal reference to tat section from the "Note well" text.

For now, perhaps something along the lines of "Note that this is inherently true when exporting a ZFS dataset via the 'sharenfs' propertly."?

[emaste]

(Do we have something like Klara's https://klarasystems.com/articles/nfs-shares-with-zfs/ in a man page or the Handbook?)

[markj]

In D44614#1017177, @emaste wrote:

Should we mention something about ZFS here? I guess there should be a high-level section on ZFS/NFS that has a xref to wherever the sharenfs property is documented, and we could have an internal reference to tat section from the "Note well" text.

Annoyingly, the documentation for sharenfs in zfsprops is a bit Linux-specific. I'll submit a patch for that.

For now, perhaps something along the lines of "Note that this is inherently true when exporting a ZFS dataset via the 'sharenfs' propertly."?

That seems reasonable.

[markj]

In D44614#1017178, @emaste wrote:

(Do we have something like Klara's https://klarasystems.com/articles/nfs-shares-with-zfs/ in a man page or the Handbook?)

It's a bit terse, but: https://docs.freebsd.org/en/books/handbook/zfs/#zfs-zfs-set-share

[markj]

Add a note about exported ZFS datasets.

[emaste]

It's a bit terse, but: https://docs.freebsd.org/en/books/handbook/zfs/#zfs-zfs-set-share

Ah, thanks - seems to approach from the wrong side (these properties control nfs sharing rather than to nfs share zfs datasets, set this) but at least it's there

[rmacklem]

I made a couple of comments, but feel free to ignore
them, since I think the patch is fine without the changes.

usr.sbin/mountd/exports.5

74

Although currently true, "local" is not required in general.
Theoretically, a remote mount other than NFS could be
exported if/when that is implemented someday.

Saying "non-NFS file system mount point" is technically
more correct, although I am not sure it is worth noting here?
(Btw, Linux does allow re-exporting of NFS mounts, although
I have avoided that, since there are nasty quirks involved.)

80

I might not say "separate" here and instead use the "file system" mantra.

[markj]

Tweak wording a bit.

[markj]

usr.sbin/mountd/exports.5

74

I'd somewhat prefer to keep it the way it is: the man page uses "local" this way in several places, and I think the use of "local" is meant to distinguish from exported file systems, as opposed to local in the sense of MNT_LOCAL, which I think is what you mean?