1. 根目录:
2. fs
3. btrfs
4. locking.h

/*
 * 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.
 */

#ifndef __BTRFS_LOCKING_
#define __BTRFS_LOCKING_

#define BTRFS_WRITE_LOCK 1
#define BTRFS_READ_LOCK 2
#define BTRFS_WRITE_LOCK_BLOCKING 3
#define BTRFS_READ_LOCK_BLOCKING 4

void btrfs_tree_lock(struct extent_buffer *eb);
void btrfs_tree_unlock(struct extent_buffer *eb);

void btrfs_tree_read_lock(struct extent_buffer *eb);
void btrfs_tree_read_unlock(struct extent_buffer *eb);
void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb);
void btrfs_set_lock_blocking_rw(struct extent_buffer *eb, int rw);
void btrfs_clear_lock_blocking_rw(struct extent_buffer *eb, int rw);
void btrfs_assert_tree_locked(struct extent_buffer *eb);
int btrfs_try_tree_read_lock(struct extent_buffer *eb);
int btrfs_try_tree_write_lock(struct extent_buffer *eb);
int btrfs_tree_read_lock_atomic(struct extent_buffer *eb);


static inline void btrfs_tree_unlock_rw(struct extent_buffer *eb, int rw)
{
	if (rw == BTRFS_WRITE_LOCK || rw == BTRFS_WRITE_LOCK_BLOCKING)
		btrfs_tree_unlock(eb);
	else if (rw == BTRFS_READ_LOCK_BLOCKING)
		btrfs_tree_read_unlock_blocking(eb);
	else if (rw == BTRFS_READ_LOCK)
		btrfs_tree_read_unlock(eb);
	else
		BUG();
}

static inline void btrfs_set_lock_blocking(struct extent_buffer *eb)
{
	btrfs_set_lock_blocking_rw(eb, BTRFS_WRITE_LOCK);
}

static inline void btrfs_clear_lock_blocking(struct extent_buffer *eb)
{
	btrfs_clear_lock_blocking_rw(eb, BTRFS_WRITE_LOCK_BLOCKING);
}
#endif