linux/fs/btrfs/locking.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright (C) 2008 Oracle.  All rights reserved.
 */

#ifndef BTRFS_LOCKING_H
#define BTRFS_LOCKING_H

#include <linux/atomic.h>
#include <linux/wait.h>
#include <linux/lockdep.h>
#include <linux/percpu_counter.h>
#include "extent_io.h"

struct extent_buffer;
struct btrfs_path;
struct btrfs_root;

#define BTRFS_WRITE_LOCK …
#define BTRFS_READ_LOCK …

/*
 * We are limited in number of subclasses by MAX_LOCKDEP_SUBCLASSES, which at
 * the time of this patch is 8, which is how many we use.  Keep this in mind if
 * you decide you want to add another subclass.
 */
enum btrfs_lock_nesting { … };

enum btrfs_lockdep_trans_states { … };

/*
 * Lockdep annotation for wait events.
 *
 * @owner:  The struct where the lockdep map is defined
 * @lock:   The lockdep map corresponding to a wait event
 *
 * This macro is used to annotate a wait event. In this case a thread acquires
 * the lockdep map as writer (exclusive lock) because it has to block until all
 * the threads that hold the lock as readers signal the condition for the wait
 * event and release their locks.
 */
#define btrfs_might_wait_for_event(owner, lock) …

/*
 * Protection for the resource/condition of a wait event.
 *
 * @owner:  The struct where the lockdep map is defined
 * @lock:   The lockdep map corresponding to a wait event
 *
 * Many threads can modify the condition for the wait event at the same time
 * and signal the threads that block on the wait event. The threads that modify
 * the condition and do the signaling acquire the lock as readers (shared
 * lock).
 */
#define btrfs_lockdep_acquire(owner, lock) …

/*
 * Used after signaling the condition for a wait event to release the lockdep
 * map held by a reader thread.
 */
#define btrfs_lockdep_release(owner, lock) …

/*
 * Macros for the transaction states wait events, similar to the generic wait
 * event macros.
 */
#define btrfs_might_wait_for_state(owner, i) …

#define btrfs_trans_state_lockdep_acquire(owner, i) …

#define btrfs_trans_state_lockdep_release(owner, i) …

/* Initialization of the lockdep map */
#define btrfs_lockdep_init_map(owner, lock) …

/* Initialization of the transaction states lockdep maps. */
#define btrfs_state_lockdep_init_map(owner, lock, state) …

static_assert(…);

void btrfs_tree_lock_nested(struct extent_buffer *eb, enum btrfs_lock_nesting nest);

static inline void btrfs_tree_lock(struct extent_buffer *eb)
{ … }

void btrfs_tree_unlock(struct extent_buffer *eb);

void btrfs_tree_read_lock_nested(struct extent_buffer *eb, enum btrfs_lock_nesting nest);

static inline void btrfs_tree_read_lock(struct extent_buffer *eb)
{ … }

void btrfs_tree_read_unlock(struct extent_buffer *eb);
int btrfs_try_tree_read_lock(struct extent_buffer *eb);
int btrfs_try_tree_write_lock(struct extent_buffer *eb);
struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root);
struct extent_buffer *btrfs_read_lock_root_node(struct btrfs_root *root);
struct extent_buffer *btrfs_try_read_lock_root_node(struct btrfs_root *root);

#ifdef CONFIG_BTRFS_DEBUG
static inline void btrfs_assert_tree_write_locked(struct extent_buffer *eb)
{ … }
#else
static inline void btrfs_assert_tree_write_locked(struct extent_buffer *eb) { }
#endif

void btrfs_unlock_up_safe(struct btrfs_path *path, int level);

static inline void btrfs_tree_unlock_rw(struct extent_buffer *eb, int rw)
{ … }

struct btrfs_drew_lock { … };

void btrfs_drew_lock_init(struct btrfs_drew_lock *lock);
void btrfs_drew_write_lock(struct btrfs_drew_lock *lock);
bool btrfs_drew_try_write_lock(struct btrfs_drew_lock *lock);
void btrfs_drew_write_unlock(struct btrfs_drew_lock *lock);
void btrfs_drew_read_lock(struct btrfs_drew_lock *lock);
void btrfs_drew_read_unlock(struct btrfs_drew_lock *lock);

#ifdef CONFIG_DEBUG_LOCK_ALLOC
void btrfs_set_buffer_lockdep_class(u64 objectid, struct extent_buffer *eb, int level);
void btrfs_maybe_reset_lockdep_class(struct btrfs_root *root, struct extent_buffer *eb);
#else
static inline void btrfs_set_buffer_lockdep_class(u64 objectid,
					struct extent_buffer *eb, int level)
{
}
static inline void btrfs_maybe_reset_lockdep_class(struct btrfs_root *root,
						   struct extent_buffer *eb)
{
}
#endif

#endif