btrfs: rename root to log in walk_down_log_tree() and walk_up_log_tree()

Everywhere we have a log root we name it as 'log' or 'log_root' except in
walk_down_log_tree() and walk_up_log_tree() where we name it as 'root',
which not only it's inconsistent, it's also confusing since we typically
use 'root' when naming variables that refer to a subvolume tree. So for
clairty and consistency rename the 'root' argument to 'log'.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Author: fdmanana

fs/btrfs/tree-log.c

@@ -2779,11 +2779,11 @@ static int clean_log_buffer(struct btrfs_trans_handle *trans,
 }
 
 static noinline int walk_down_log_tree(struct btrfs_trans_handle *trans,
-				   struct btrfs_root *root,
+				   struct btrfs_root *log,
 				   struct btrfs_path *path, int *level,
 				   struct walk_control *wc)
 {
-	struct btrfs_fs_info *fs_info = root->fs_info;
+	struct btrfs_fs_info *fs_info = log->fs_info;
 	u64 bytenr;
 	u64 ptr_gen;
 	struct extent_buffer *next;
@@ -2821,8 +2821,7 @@ static noinline int walk_down_log_tree(struct btrfs_trans_handle *trans,
 		}
 
 		if (*level == 1) {
-			ret = wc->process_func(root, next, wc, ptr_gen,
-					       *level - 1);
+			ret = wc->process_func(log, next, wc, ptr_gen, *level - 1);
 			if (ret) {
 				free_extent_buffer(next);
 				return ret;
@@ -2873,7 +2872,7 @@ static noinline int walk_down_log_tree(struct btrfs_trans_handle *trans,
 }
 
 static noinline int walk_up_log_tree(struct btrfs_trans_handle *trans,
-				 struct btrfs_root *root,
+				 struct btrfs_root *log,
 				 struct btrfs_path *path, int *level,
 				 struct walk_control *wc)
 {
@@ -2889,7 +2888,7 @@ static noinline int walk_up_log_tree(struct btrfs_trans_handle *trans,
 			WARN_ON(*level == 0);
 			return 0;
 		} else {
-			ret = wc->process_func(root, path->nodes[*level], wc,
+			ret = wc->process_func(log, path->nodes[*level], wc,
 				 btrfs_header_generation(path->nodes[*level]),
 				 *level);
 			if (ret)