LXR linux/fs/btrfs/locking.h

   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
  72