1 files changed, 74 insertions, 0 deletions
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
new file mode 100644
index 000000000000..0cc314c10d66
--- /dev/null
+++ b/fs/btrfs/locking.c
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2008 Oracle.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program 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 021110-1307, USA.
+ */
+#include <linux/sched.h>
+#include <linux/gfp.h>
+#include <linux/pagemap.h>
+#include <linux/spinlock.h>
+#include <linux/page-flags.h>
+#include <asm/bug.h>
+#include "ctree.h"
+#include "extent_io.h"
+#include "locking.h"
+
+int btrfs_tree_lock(struct extent_buffer *eb)
+{
+	int i;
+
+	if (mutex_trylock(&eb->mutex))
+		return 0;
+	for (i = 0; i < 512; i++) {
+		cpu_relax();
+		if (mutex_trylock(&eb->mutex))
+			return 0;
+	}
+	cpu_relax();
+	mutex_lock_nested(&eb->mutex, BTRFS_MAX_LEVEL - btrfs_header_level(eb));
+	return 0;
+}
+
+int btrfs_try_tree_lock(struct extent_buffer *eb)
+{
+	return mutex_trylock(&eb->mutex);
+}
+
+int btrfs_tree_unlock(struct extent_buffer *eb)
+{
+	mutex_unlock(&eb->mutex);
+	return 0;
+}
+
+int btrfs_tree_locked(struct extent_buffer *eb)
+{
+	return mutex_is_locked(&eb->mutex);
+}
+
+int btrfs_path_lock_waiting(struct btrfs_path *path, int level)
+{
+	int i;
+	struct extent_buffer *eb;
+	for (i = level; i <= level + 1 && i < BTRFS_MAX_LEVEL; i++) {
+		eb = path->nodes[i];
+		if (!eb)
+			break;
+		smp_mb();
+		if (!list_empty(&eb->mutex.wait_list))
+			return 1;
+	}
+	return 0;
+}
+