kern/147881: [zfs] [patch] ZFS "sharenfs" doesn't allow different "exports" options for different hosts

[Andrey Simonenko]

The following reply was made to PR kern/147881; it has been noted by GNATS.

From: Andrey Simonenko <simon at comsys.ntu-kpi.kiev.ua>
To: bug-followup at FreeBSD.org
Cc: Richard Conto <richard.conto at gmail.com>,
	Martin Matuska <mm at FreeBSD.org>
Subject: Re: kern/147881: [zfs] [patch] ZFS "sharenfs" doesn't allow
 different "exports" options for different hosts
Date: Mon, 10 Sep 2012 14:40:08 +0300

 On Fri, Sep 07, 2012 at 06:10:07PM +0000, Richard Conto wrote:
 >  
 >  > The purpose of the sharenfs property is not to completely replace
 >  > /etc/exports.
 >  > What we have is just a tricky workaround that populates =
 >  /etc/zfs/exports.
 >  > T
 >  > he commands to NFS-share filesystems on illumos are different and our
 >  > options are mostly incompatible with illumos.
 >  > So you e.g. sharenfs=3D"-maproot=3Droot" is invalid if imported on a
 >  > Openindiana system.
 >  >=20
 >  > Have you considered using just /etc/exports for more-complex =
 >  configurations?
 >  
 >  Yes. It doesn't scale - and scaling is the whole purpose of NFS.  It =
 >  also makes it difficult for distributed management of access rights to =
 >  end-user NFS exports.
 >  
 >  I wouldn't mind using a FreeBSD specific attribute to populate =
 >  /etc/zfs/exports with FreeBSD specific values such as is used for =
 >  swapping to ZFS.  Merging the two different attributes would either be =
 >  tricky, or the use of the FreeBSD one should cause "sharenfs" to be =
 >  ignored entirely.
 
 This is a limitation of exports(5) format, that does not allow to specify
 all settings for one file system in one line.  When I had similar task
 I allowed to redefine options in one line, so address specifications can
 inherit already specified settings and can get changed or new settings.
 
 For example: /fs -ro -mapall user1 host1 -mapall user2 host2 host3 -rw host4
 
 Here, /fs is exported read-only for host{1,2,3} and read-write for host4,
 all users are mapped to user1 for host1 and all users are mapped to user2
 for host{2,3,4}.
 
 More information about format of NFS exports settings that I propose
 is available here:
 
 http://nfse.sourceforge.net/nfs.exports.5.html