NEX-15279 support NFS server in zone
NEX-15520 online NFS shares cause zoneadm halt to hang in nfs_export_zone_fini
Portions contributed by: Dan Kruchinin dan.kruchinin@nexenta.com
Portions contributed by: Stepan Zastupov stepan.zastupov@gmail.com
Reviewed by: Joyce McIntosh <joyce.mcintosh@nexenta.com>
Reviewed by: Rob Gittins <rob.gittins@nexenta.com>
Reviewed by: Gordon Ross <gordon.ross@nexenta.com>

*** 16,31 ****
   * fields enclosed by brackets "[]" replaced with your own identifying
   * information: Portions Copyright [yyyy] [name of copyright owner]
   *
   * CDDL HEADER END
   */
  /*
   * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  /*
!  * Copyright 2012 Nexenta Systems, Inc. All rights reserved.
   */
  
  #include <sys/systm.h>
  #include <sys/cmn_err.h>
  #include <nfs/nfs.h>
--- 16,33 ----
   * fields enclosed by brackets "[]" replaced with your own identifying
   * information: Portions Copyright [yyyy] [name of copyright owner]
   *
   * CDDL HEADER END
   */
+ 
  /*
   * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
+ 
  /*
!  * Copyright 2018 Nexenta Systems, Inc.
   */
  
  #include <sys/systm.h>
  #include <sys/cmn_err.h>
  #include <nfs/nfs.h>
*** 131,141 ****
          struct nfs4_svgetit_arg sarg;
          struct compound_state cs;
          struct statvfs64 sb;
  
          rfs4_init_compound_state(&cs);
!         cs.vp = rootvp;
          cs.fh.nfs_fh4_val = NULL;
          cs.cr = kcred;
  
          /*
           * Get all the supported attributes
--- 133,143 ----
          struct nfs4_svgetit_arg sarg;
          struct compound_state cs;
          struct statvfs64 sb;
  
          rfs4_init_compound_state(&cs);
!         cs.vp = ZONE_ROOTVP();
          cs.fh.nfs_fh4_val = NULL;
          cs.cr = kcred;
  
          /*
           * Get all the supported attributes
*** 1314,1324 ****
                   * for a VROOT object.  sarg->vap was setup
                   * before we got here, so there's no need to do
                   * another getattr -- just use the one in sarg.
                   */
                  if (VN_CMP(vp, stubvp)) {
!                         ASSERT(VN_CMP(vp, rootdir));
                          vap = sarg->vap;
                  } else {
                          va.va_mask = AT_NODEID;
                          vap = &va;
                          error = rfs4_vop_getattr(stubvp, vap, 0, sarg->cs->cr);
--- 1316,1326 ----
                   * for a VROOT object.  sarg->vap was setup
                   * before we got here, so there's no need to do
                   * another getattr -- just use the one in sarg.
                   */
                  if (VN_CMP(vp, stubvp)) {
!                         ASSERT(VN_CMP(vp, ZONE_ROOTVP()));
                          vap = sarg->vap;
                  } else {
                          va.va_mask = AT_NODEID;
                          vap = &va;
                          error = rfs4_vop_getattr(stubvp, vap, 0, sarg->cs->cr);