fs/btrfs/locking.h

File Facts

System

Linux kernel

Corpus path

fs/btrfs/locking.h

Extension

.h

Size

8264 bytes

Lines

252

Domain

Core OS

Bucket

VFS And Filesystem Core

Inferred role

Core OS: implementation source

Status

source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

• Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.
• Uses kernel synchronization; read lock ordering, sleepability, and interrupt context assumptions before translating.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/atomic.h
• linux/wait.h
• linux/lockdep.h
• linux/percpu_counter.h
• extent_io.h

Detected Declarations

• struct extent_buffer
• struct btrfs_path
• struct btrfs_root
• struct btrfs_drew_lock
• enum btrfs_lock_nesting
• enum btrfs_lockdep_trans_states
• function btrfs_tree_lock
• function btrfs_tree_read_lock
• function btrfs_assert_tree_write_locked
• function btrfs_assert_tree_read_locked
• function btrfs_assert_tree_write_locked
• function btrfs_tree_unlock_rw
• function btrfs_set_buffer_lockdep_class

Annotated Snippet

struct btrfs_drew_lock {
	atomic_t readers;
	atomic_t writers;
	wait_queue_head_t pending_writers;
	wait_queue_head_t pending_readers;
};

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

Annotation

• Immediate include surface: `linux/atomic.h`, `linux/wait.h`, `linux/lockdep.h`, `linux/percpu_counter.h`, `extent_io.h`.
• Detected declarations: `struct extent_buffer`, `struct btrfs_path`, `struct btrfs_root`, `struct btrfs_drew_lock`, `enum btrfs_lock_nesting`, `enum btrfs_lockdep_trans_states`, `function btrfs_tree_lock`, `function btrfs_tree_read_lock`, `function btrfs_assert_tree_write_locked`, `function btrfs_assert_tree_read_locked`.
• Atlas domain: Core OS / VFS And Filesystem Core.
• Implementation status: source implementation candidate.
• Synchronization appears in or near this file; preserve lock ordering, sleepability, and interrupt-context constraints.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.