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
19#ifndef __BTRFS_LOCKING_
20#define __BTRFS_LOCKING_
 
 
 
 
 
21
22#define BTRFS_WRITE_LOCK 1
23#define BTRFS_READ_LOCK 2
24#define BTRFS_WRITE_LOCK_BLOCKING 3
25#define BTRFS_READ_LOCK_BLOCKING 4
26
27int btrfs_tree_lock(struct extent_buffer *eb);
28int btrfs_tree_unlock(struct extent_buffer *eb);
29int btrfs_try_spin_lock(struct extent_buffer *eb);
 
30
31void btrfs_tree_read_lock(struct extent_buffer *eb);
32void btrfs_tree_read_unlock(struct extent_buffer *eb);
33void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb);
34void btrfs_set_lock_blocking_rw(struct extent_buffer *eb, int rw);
35void btrfs_clear_lock_blocking_rw(struct extent_buffer *eb, int rw);
36void btrfs_assert_tree_locked(struct extent_buffer *eb);
37int btrfs_try_tree_read_lock(struct extent_buffer *eb);
38int btrfs_try_tree_write_lock(struct extent_buffer *eb);
 
 
 
 
 
 
 
 
 
 
 
 
39
40static inline void btrfs_tree_unlock_rw(struct extent_buffer *eb, int rw)
41{
42	if (rw == BTRFS_WRITE_LOCK || rw == BTRFS_WRITE_LOCK_BLOCKING)
43		btrfs_tree_unlock(eb);
44	else if (rw == BTRFS_READ_LOCK_BLOCKING)
45		btrfs_tree_read_unlock_blocking(eb);
46	else if (rw == BTRFS_READ_LOCK)
47		btrfs_tree_read_unlock(eb);
48	else
49		BUG();
50}
51
52static inline void btrfs_set_lock_blocking(struct extent_buffer *eb)
53{
54	btrfs_set_lock_blocking_rw(eb, BTRFS_WRITE_LOCK);
55}
 
 
 
 
 
 
 
 
 
 
56
57static inline void btrfs_clear_lock_blocking(struct extent_buffer *eb)
58{
59	btrfs_clear_lock_blocking_rw(eb, BTRFS_WRITE_LOCK_BLOCKING);
60}
61#endif

 1/* SPDX-License-Identifier: GPL-2.0 */
 2/*
 3 * Copyright (C) 2008 Oracle.  All rights reserved.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 4 */
 5
 6#ifndef BTRFS_LOCKING_H
 7#define BTRFS_LOCKING_H
 8
 9#include <linux/atomic.h>
10#include <linux/wait.h>
11#include <linux/percpu_counter.h>
12#include "extent_io.h"
13
14#define BTRFS_WRITE_LOCK 1
15#define BTRFS_READ_LOCK 2
16#define BTRFS_WRITE_LOCK_BLOCKING 3
17#define BTRFS_READ_LOCK_BLOCKING 4
18
19struct btrfs_path;
20
21void btrfs_tree_lock(struct extent_buffer *eb);
22void btrfs_tree_unlock(struct extent_buffer *eb);
23
24void btrfs_tree_read_lock(struct extent_buffer *eb);
25void btrfs_tree_read_unlock(struct extent_buffer *eb);
26void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb);
27void btrfs_set_lock_blocking_read(struct extent_buffer *eb);
28void btrfs_set_lock_blocking_write(struct extent_buffer *eb);
 
29int btrfs_try_tree_read_lock(struct extent_buffer *eb);
30int btrfs_try_tree_write_lock(struct extent_buffer *eb);
31int btrfs_tree_read_lock_atomic(struct extent_buffer *eb);
32
33#ifdef CONFIG_BTRFS_DEBUG
34static inline void btrfs_assert_tree_locked(struct extent_buffer *eb) {
35	BUG_ON(!eb->write_locks);
36}
37#else
38static inline void btrfs_assert_tree_locked(struct extent_buffer *eb) { }
39#endif
40
41void btrfs_set_path_blocking(struct btrfs_path *p);
42void btrfs_unlock_up_safe(struct btrfs_path *path, int level);
43
44static inline void btrfs_tree_unlock_rw(struct extent_buffer *eb, int rw)
45{
46	if (rw == BTRFS_WRITE_LOCK || rw == BTRFS_WRITE_LOCK_BLOCKING)
47		btrfs_tree_unlock(eb);
48	else if (rw == BTRFS_READ_LOCK_BLOCKING)
49		btrfs_tree_read_unlock_blocking(eb);
50	else if (rw == BTRFS_READ_LOCK)
51		btrfs_tree_read_unlock(eb);
52	else
53		BUG();
54}
55
56struct btrfs_drew_lock {
57	atomic_t readers;
58	struct percpu_counter writers;
59	wait_queue_head_t pending_writers;
60	wait_queue_head_t pending_readers;
61};
62
63int btrfs_drew_lock_init(struct btrfs_drew_lock *lock);
64void btrfs_drew_lock_destroy(struct btrfs_drew_lock *lock);
65void btrfs_drew_write_lock(struct btrfs_drew_lock *lock);
66bool btrfs_drew_try_write_lock(struct btrfs_drew_lock *lock);
67void btrfs_drew_write_unlock(struct btrfs_drew_lock *lock);
68void btrfs_drew_read_lock(struct btrfs_drew_lock *lock);
69void btrfs_drew_read_unlock(struct btrfs_drew_lock *lock);
70
 
 
 
 
71#endif