fs/btrfs/locking.c

   1 /*
   2  * Copyright (C) 2008 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/gfp.h>
  20 #include <linux/pagemap.h>
  21 #include <linux/spinlock.h>
  22 #include <linux/page-flags.h>
  23 #include <linux/bug.h>
  24 #include "ctree.h"
  25 #include "extent_io.h"
  26 #include "locking.h"
  27
  28 int btrfs_tree_lock(struct extent_buffer *eb)
  29 {
  30         lock_page(eb->first_page);
  31         return 0;
  32 }
  33
  34 int btrfs_try_tree_lock(struct extent_buffer *eb)
  35 {
  36         return TestSetPageLocked(eb->first_page);
  37 }
  38
  39 int btrfs_tree_unlock(struct extent_buffer *eb)
  40 {
  41         WARN_ON(!PageLocked(eb->first_page));
  42         unlock_page(eb->first_page);
  43         return 0;
  44 }
  45
  46 int btrfs_tree_locked(struct extent_buffer *eb)
  47 {
  48         return PageLocked(eb->first_page);
  49 }
  50