btrfs: Document a mutex lock/unlock sequence (8cc33e5c) · Commits · 戴 / test

fs/btrfs/extent-tree.c

+12 −0

Original line number	Original line	Diff line number	Diff line
	@@ -756,6 +756,10 @@ again:

	btrfs_release_path(path);		btrfs_release_path(path);

			/*
			* Mutex was contended, block until it's released and try
			* again
			*/
	mutex_lock(&head->mutex);		mutex_lock(&head->mutex);
	mutex_unlock(&head->mutex);		mutex_unlock(&head->mutex);
	btrfs_put_delayed_ref(&head->node);		btrfs_put_delayed_ref(&head->node);
	@@ -2297,6 +2301,10 @@ again:
	atomic_inc(&ref->refs);		atomic_inc(&ref->refs);

	spin_unlock(&delayed_refs->lock);		spin_unlock(&delayed_refs->lock);
			/*
			* Mutex was contended, block until it's
			* released and try again
			*/
	mutex_lock(&head->mutex);		mutex_lock(&head->mutex);
	mutex_unlock(&head->mutex);		mutex_unlock(&head->mutex);

	@@ -2363,6 +2371,10 @@ static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,

	btrfs_release_path(path);		btrfs_release_path(path);

			/*
			* Mutex was contended, block until it's released and let
			* caller try again
			*/
	mutex_lock(&head->mutex);		mutex_lock(&head->mutex);
	mutex_unlock(&head->mutex);		mutex_unlock(&head->mutex);
	btrfs_put_delayed_ref(&head->node);		btrfs_put_delayed_ref(&head->node);