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
  19 struct btrfs_path;
  20
  21 void btrfs_tree_lock(struct extent_buffer *eb);
  22 void btrfs_tree_unlock(struct extent_buffer *eb);
  23
  24 void btrfs_tree_read_lock(struct extent_buffer *eb);
  25 void btrfs_tree_read_unlock(struct extent_buffer *eb);
  26 void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb);
  27 void btrfs_set_lock_blocking_read(struct extent_buffer *eb);
  28 void btrfs_set_lock_blocking_write(struct extent_buffer *eb);
  29 int btrfs_try_tree_read_lock(struct extent_buffer *eb);
  30 int btrfs_try_tree_write_lock(struct extent_buffer *eb);
  31 int btrfs_tree_read_lock_atomic(struct extent_buffer *eb);
  32
  33 #ifdef CONFIG_BTRFS_DEBUG
  34 static inline void btrfs_assert_tree_locked(struct extent_buffer *eb) {
  35         BUG_ON(!eb->write_locks);
  36 }
  37 #else
  38 static inline void btrfs_assert_tree_locked(struct extent_buffer *eb) { }
  39 #endif
  40
  41 void btrfs_set_path_blocking(struct btrfs_path *p);
  42 void btrfs_unlock_up_safe(struct btrfs_path *path, int level);
  43
  44 static 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
  56 struct 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
  63 int btrfs_drew_lock_init(struct btrfs_drew_lock *lock);
  64 void btrfs_drew_lock_destroy(struct btrfs_drew_lock *lock);
  65 void btrfs_drew_write_lock(struct btrfs_drew_lock *lock);
  66 bool btrfs_drew_try_write_lock(struct btrfs_drew_lock *lock);
  67 void btrfs_drew_write_unlock(struct btrfs_drew_lock *lock);
  68 void btrfs_drew_read_lock(struct btrfs_drew_lock *lock);
  69 void btrfs_drew_read_unlock(struct btrfs_drew_lock *lock);
  70
  71 #endif