/*
   Copyright (C) 1999, 2001 Free Software Foundation, Inc.
   Written by Thomas Bushnell, BSG.

   This file is part of the GNU Hurd.

   The GNU Hurd is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2, or (at
   your option) any later version.

   The GNU Hurd is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA. */

#include "priv.h"

/* Unlock node NP and release a hard reference; if this is the last
   hard reference and there are no links to the file then request
   weak references to be dropped.  */
void
diskfs_nput (struct node *np)
{
  int tried_drop_softrefs = 0;

 loop:
  pthread_spin_lock (&diskfs_node_refcnt_lock);
  assert (np->references);
  np->references--;
  if (np->references + np->light_references == 0)
    diskfs_drop_node (np);
  else if (np->references == 0 && !tried_drop_softrefs)
    {
      pthread_spin_unlock (&diskfs_node_refcnt_lock);

      /* This is our cue that something akin to "last process closes file"
	 in the POSIX.1 sense happened, so make sure any pending node time
	 updates now happen in a timely fashion.  */
      diskfs_set_node_times (np);

      diskfs_lost_hardrefs (np);
      if (!np->dn_stat.st_nlink)
	{
	  /* There are no links.  If there are soft references that
	     can be dropped, we can't let them postpone deallocation.
	     So attempt to drop them.  But that's a user-supplied
	     routine, which might result in further recursive calls to
	     the ref-counting system.  So we have to reacquire our
	     reference around the call to forestall disaster. */
	  pthread_spin_lock (&diskfs_node_refcnt_lock);
	  np->references++;
	  pthread_spin_unlock (&diskfs_node_refcnt_lock);

	  if (np->sockaddr != MACH_PORT_NULL)
	    {
	      mach_port_deallocate (mach_task_self (), np->sockaddr);
	      np->sockaddr = MACH_PORT_NULL;
	    }

	  diskfs_try_dropping_softrefs (np);

	  /* But there's no value in looping forever in this
	     routine; only try to drop soft refs once. */
	  tried_drop_softrefs = 1;

	  /* Now we can drop the reference back... */
	  goto loop;
	}
      pthread_mutex_unlock (&np->lock);
    }
  else
    {
      pthread_spin_unlock (&diskfs_node_refcnt_lock);
      pthread_mutex_unlock (&np->lock);
    }
}