btrfs: move root node locking helpers to locking.c

The helpers are related to locking so move them there, update comments.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 968faae..b62721a 100644 (file)
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -143,44 +143,6 @@ struct extent_buffer *btrfs_root_node(struct btrfs_root *root)
        return eb;
 }
 
-/* loop around taking references on and locking the root node of the
- * tree until you end up with a lock on the root.  A locked buffer
- * is returned, with a reference held.
- */
-struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root)
-{
-       struct extent_buffer *eb;
-
-       while (1) {
-               eb = btrfs_root_node(root);
-               btrfs_tree_lock(eb);
-               if (eb == root->node)
-                       break;
-               btrfs_tree_unlock(eb);
-               free_extent_buffer(eb);
-       }
-       return eb;
-}
-
-/* loop around taking references on and locking the root node of the
- * tree until you end up with a lock on the root.  A locked buffer
- * is returned, with a reference held.
- */
-struct extent_buffer *btrfs_read_lock_root_node(struct btrfs_root *root)
-{
-       struct extent_buffer *eb;
-
-       while (1) {
-               eb = btrfs_root_node(root);
-               btrfs_tree_read_lock(eb);
-               if (eb == root->node)
-                       break;
-               btrfs_tree_read_unlock(eb);
-               free_extent_buffer(eb);
-       }
-       return eb;
-}
-
 /* cowonly root (everything not a reference counted cow subvolume), just get
  * put onto a simple dirty list.  transaction.c walks this to make sure they
  * get properly updated on disk.

diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
index 571c482..e713900 100644 (file)
--- a/fs/btrfs/locking.c
+++ b/fs/btrfs/locking.c
@@ -523,3 +523,45 @@ void btrfs_unlock_up_safe(struct btrfs_path *path, int level)
                path->locks[i] = 0;
        }
 }
+
+/*
+ * Loop around taking references on and locking the root node of the tree until
+ * we end up with a lock on the root node.
+ *
+ * Return: root extent buffer with write lock held
+ */
+struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root)
+{
+       struct extent_buffer *eb;
+
+       while (1) {
+               eb = btrfs_root_node(root);
+               btrfs_tree_lock(eb);
+               if (eb == root->node)
+                       break;
+               btrfs_tree_unlock(eb);
+               free_extent_buffer(eb);
+       }
+       return eb;
+}
+
+/*
+ * Loop around taking references on and locking the root node of the tree until
+ * we end up with a lock on the root node.
+ *
+ * Return: root extent buffer with read lock held
+ */
+struct extent_buffer *btrfs_read_lock_root_node(struct btrfs_root *root)
+{
+       struct extent_buffer *eb;
+
+       while (1) {
+               eb = btrfs_root_node(root);
+               btrfs_tree_read_lock(eb);
+               if (eb == root->node)
+                       break;
+               btrfs_tree_read_unlock(eb);
+               free_extent_buffer(eb);
+       }
+       return eb;
+}