1 files changed, 69 insertions, 0 deletions
diff --git a/libdiskfs/node-nput.c b/libdiskfs/node-nput.c
new file mode 100644
index 00000000..425b2216
--- /dev/null
+++ b/libdiskfs/node-nput.c
@@ -0,0 +1,69 @@
+/* 
+   Copyright (C) 1999 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
+   soft references to be dropped.  */
+void
+diskfs_nput (struct node *np)
+{
+  int tried_drop_softrefs = 0;
+
+ loop:
+  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)
+    {
+      spin_unlock (&diskfs_node_refcnt_lock);
+      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. */
+	  spin_lock (&diskfs_node_refcnt_lock);
+	  np->references++;
+	  spin_unlock (&diskfs_node_refcnt_lock);
+
+	  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;
+	}
+      mutex_unlock (&np->lock);
+    }
+  else
+    {
+      spin_unlock (&diskfs_node_refcnt_lock);
+      mutex_unlock (&np->lock);
+    }
+}