fs/btrfs/locking.c

19  * eb, the lockdep key is determined by the btrfs_root it belongs to and
20  * the level the eb occupies in the tree.
83 void btrfs_set_buffer_lockdep_class(u64 objectid, struct extent_buffer *eb, int level)
94 	lockdep_set_class_and_name(&eb->lock, &ks->keys[level], ks->names[level]);
97 void btrfs_maybe_reset_lockdep_class(struct btrfs_root *root, struct extent_buffer *eb)
101 					       eb, btrfs_header_level(eb));
107 static void btrfs_set_eb_lock_owner(struct extent_buffer *eb, pid_t owner)
109 	eb->lock_owner = owner;
112 static void btrfs_set_eb_lock_owner(struct extent_buffer *eb, pid_t owner) { }
133  * @eb:		the eb to be locked
139 void __btrfs_tree_read_lock(struct extent_buffer *eb, enum btrfs_lock_nesting nest)
146 	down_read_nested(&eb->lock, nest);
147 	trace_btrfs_tree_read_lock(eb, start_ns);
150 void btrfs_tree_read_lock(struct extent_buffer *eb)
152 	__btrfs_tree_read_lock(eb, BTRFS_NESTING_NORMAL);
160 int btrfs_try_tree_read_lock(struct extent_buffer *eb)
162 	if (down_read_trylock(&eb->lock)) {
163 		trace_btrfs_try_tree_read_lock(eb);
174 int btrfs_try_tree_write_lock(struct extent_buffer *eb)
176 	if (down_write_trylock(&eb->lock)) {
177 		btrfs_set_eb_lock_owner(eb, current->pid);
178 		trace_btrfs_try_tree_write_lock(eb);
187 void btrfs_tree_read_unlock(struct extent_buffer *eb)
189 	trace_btrfs_tree_read_unlock(eb);
190 	up_read(&eb->lock);
194  * Lock eb for write.
196  * @eb:		the eb to lock
199  * Returns with the eb->lock write locked.
201 void __btrfs_tree_lock(struct extent_buffer *eb, enum btrfs_lock_nesting nest)
202 	__acquires(&eb->lock)
209 	down_write_nested(&eb->lock, nest);
210 	btrfs_set_eb_lock_owner(eb, current->pid);
211 	trace_btrfs_tree_lock(eb, start_ns);
214 void btrfs_tree_lock(struct extent_buffer *eb)
216 	__btrfs_tree_lock(eb, BTRFS_NESTING_NORMAL);
222 void btrfs_tree_unlock(struct extent_buffer *eb)
224 	trace_btrfs_tree_unlock(eb);
225 	btrfs_set_eb_lock_owner(eb, 0);
226 	up_write(&eb->lock);
263 	struct extent_buffer *eb;
266 		eb = btrfs_root_node(root);
268 		btrfs_maybe_reset_lockdep_class(root, eb);
269 		btrfs_tree_lock(eb);
270 		if (eb == root->node)
272 		btrfs_tree_unlock(eb);
273 		free_extent_buffer(eb);
275 	return eb;
286 	struct extent_buffer *eb;
289 		eb = btrfs_root_node(root);
291 		btrfs_maybe_reset_lockdep_class(root, eb);
292 		btrfs_tree_read_lock(eb);
293 		if (eb == root->node)
295 		btrfs_tree_read_unlock(eb);
296 		free_extent_buffer(eb);
298 	return eb;
310 	struct extent_buffer *eb;
313 		eb = btrfs_root_node(root);
314 		if (!btrfs_try_tree_read_lock(eb)) {
315 			free_extent_buffer(eb);
318 		if (eb == root->node)
320 		btrfs_tree_read_unlock(eb);
321 		free_extent_buffer(eb);
323 	return eb;