[PATCH v3 2/2] btrfs: use enum instead of constant value

[Gu Jinxiang <gujx@cn.fujitsu.com>]

From: Gu JinXiang <gujx@cn.fujitsu.com>

load_free_space_tree calls either function load_free_space_bitmaps or
load_free_space_extents. And either of those two will lead to call
btrfs_next_item.
So in function load_free_space_tree, use READA_FORWARD to read forward
ahead.

Changelog:
v2->v1: change enum from READA_BACK to READA_FORWARD, since according
to the logic of the source, it should reada_for_search forward, not
backward.
And, Reference:
commit e4058b54d1e4 ("btrfs: cleanup, use enum values for btrfs_path reada")

v3->v2: add commit message to make it easy to understand. And split it
to two patch.

Signed-off-by: Gu JinXiang <gujx@cn.fujitsu.com>
---
 fs/btrfs/free-space-tree.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/free-space-tree.c b/fs/btrfs/free-space-tree.c
index d7b6c0017143..af36a6a971fe 100644
--- a/fs/btrfs/free-space-tree.c
+++ b/fs/btrfs/free-space-tree.c
@@ -1573,7 +1573,7 @@ int load_free_space_tree(struct btrfs_caching_control *caching_ctl)
 	 */
 	path->skip_locking = 1;
 	path->search_commit_root = 1;
-	path->reada = 1;
+	path->reada = READA_FORWARD;
 
 	info = search_free_space_info(NULL, fs_info, block_group, path, 0);
 	if (IS_ERR(info)) {
-- 
2.14.3