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review.shift-gmbh.com / SHIFTPHONES / mainline / linux / c4615b2b4f3e5789b48395321f679519fd4f2b81 / . / fs / btrfs / locking.h
blob: d715846c10b8d3b40c00d4c74febed9196c95d30 [file] [log] [blame]
David Sterba9888c342018-04-03 19:16:55 +0200[diff] [blame]1/* SPDX-License-Identifier: GPL-2.0 */
Chris Mason925baed2008-06-25 16:01:30 -0400[diff] [blame]2/*
3 * Copyright (C) 2008 Oracle. All rights reserved.
Chris Mason925baed2008-06-25 16:01:30 -0400[diff] [blame]4 */
5
David Sterba9888c342018-04-03 19:16:55 +0200[diff] [blame]6#ifndef BTRFS_LOCKING_H
7#define BTRFS_LOCKING_H
Chris Mason925baed2008-06-25 16:01:30 -0400[diff] [blame]8
Nikolay Borisov2992df72020-01-30 14:59:44 +0200[diff] [blame]9#include <linux/atomic.h>
10#include <linux/wait.h>
11#include <linux/percpu_counter.h>
David Sterba31f6e762019-09-24 18:44:24 +0200[diff] [blame]12#include "extent_io.h"
13
Chris Masonbd681512011-07-16 15:23:14 -0400[diff] [blame]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
Nikolay Borisov2992df72020-01-30 14:59:44 +0200[diff] [blame]19struct btrfs_path;
20
Jeff Mahoney143bede2012-03-01 14:56:26 +0100[diff] [blame]21void btrfs_tree_lock(struct extent_buffer *eb);
22void btrfs_tree_unlock(struct extent_buffer *eb);
Chris Masonb4ce94d2009-02-04 09:25:08 -0500[diff] [blame]23
Chris Masonbd681512011-07-16 15:23:14 -0400[diff] [blame]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);
David Sterbab95be2d2018-04-04 01:43:05 +0200[diff] [blame]27void btrfs_set_lock_blocking_read(struct extent_buffer *eb);
28void btrfs_set_lock_blocking_write(struct extent_buffer *eb);
Chris Masonbd681512011-07-16 15:23:14 -0400[diff] [blame]29int btrfs_try_tree_read_lock(struct extent_buffer *eb);
30int btrfs_try_tree_write_lock(struct extent_buffer *eb);
Chris Masonf82c4582014-11-19 10:25:09 -0800[diff] [blame]31int btrfs_tree_read_lock_atomic(struct extent_buffer *eb);
32
David Sterba31f6e762019-09-24 18:44:24 +0200[diff] [blame]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
Chris Masonbd681512011-07-16 15:23:14 -0400[diff] [blame]40
David Sterbaed2b1d32019-09-24 19:17:17 +0200[diff] [blame]41void btrfs_set_path_blocking(struct btrfs_path *p);
David Sterba1f95ec02019-09-24 19:17:17 +0200[diff] [blame]42void btrfs_unlock_up_safe(struct btrfs_path *path, int level);
David Sterbaed2b1d32019-09-24 19:17:17 +0200[diff] [blame]43
Chris Masonbd681512011-07-16 15:23:14 -0400[diff] [blame]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
Nikolay Borisov2992df72020-01-30 14:59:44 +0200[diff] [blame]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
Chris Mason925baed2008-06-25 16:01:30 -0400[diff] [blame]71#endif