2988 nfssrv: need ability to go to submounts for v3 and v2 protocols
Portions contributed by: Marcel Telka <marcel.telka@nexenta.com>
Portions contributed by: Jean McCormack <jean.mccormack@nexenta.com>
Reviewed by: Yuri Pankov <yuri.pankov@nexenta.com>
Reviewed by: Alek Pinchuk <alek.pinchuk@nexenta.com>
Reviewed by: Dan Fields <dan.fields@nexenta.com>
Reviewed by: Dan McDonald <danmcd@joyent.com>
Change-Id: I6fdf110cc17e789353c4442b83a46cb80643456e

@@ -170,10 +170,29 @@
 is specified, the default values associated with the global tag in
 .Pa /etc/nfs/nfslog.conf
 are used.
 Support of NFS server logging is only available for NFS Version 2 and
 Version 3 requests.
+.It Sy nohide
+By default, if server exports two filesystems, one of which is mounted as a
+child of the other, NFS Version 2 and Version 3 clients must mount both
+filesystems explicitly in order to access them.
+If a client only mounts the parent, it will see an empty directory at the
+location where the other filesystem is mounted.
+.Pp
+Setting the
+.Sy nohide
+option on a filesystem causes it to no longer be hidden in this manner, and the
+client will be able to move from the parent filesystem to this one without
+noticing the change.
+However, some NFS clients or applications may not function correctly when
+this option is used.
+In particular, files on different underlying filesystems may appear to have
+the same inode numbers.
+The
+.Sy nohide
+option only applies to NFS Version 2 and Version 3 requests.
 .It Sy noaclfab
 By default, the NFS server will fabricate POSIX-draft style ACLs in response
 to ACL requests from NFS Version 2 or Version 3 clients accessing shared
 file systems that do not support POSIX-draft ACLs (such as ZFS).
 Specifying

@@ -784,5 +803,16 @@
 use of
 .Pa /export/foo
 does not work as it does with NFS Version 2 and Version 3 and the client
 receives an error when attempting to mount
 .Pa /export/foo .
+.Pp
+The
+.Sy nohide
+option violates RFC 1094,
+.%T "Network File System Protocol Specification"
+and RFC 1813,
+.%T "NFS: Network File System Version 3 Protocol Specification"
+.Pp
+The
+.Sy nohide
+option is provided for compatibility with Linux NFS.