btrfs: Remove 'objectid' member from struct btrfs_root

There are two members in struct btrfs_root which indicate root's
objectid: objectid and root_key.objectid.

They are both set to the same value in __setup_root():

  static void __setup_root(struct btrfs_root *root,
                           struct btrfs_fs_info *fs_info,
                           u64 objectid)
  {
    ...
    root->objectid = objectid;
    ...
    root->root_key.objectid = objecitd;
    ...
  }

and not changed to other value after initialization.

grep in btrfs directory shows both are used in many places:
  $ grep -rI "root->root_key.objectid" | wc -l
  133
  $ grep -rI "root->objectid" | wc -l
  55
 (4.17, inc. some noise)

It is confusing to have two similar variable names and it seems
that there is no rule about which should be used in a certain case.

Since ->root_key itself is needed for tree reloc tree, let's remove
'objecitd' member and unify code to use ->root_key.objectid in all places.

Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index d436fb4c002e..1f71695cb0a8 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -207,7 +207,7 @@ static void add_root_to_dirty_list(struct btrfs_root *root)
 	spin_lock(&fs_info->trans_lock);
 	if (!test_and_set_bit(BTRFS_ROOT_DIRTY, &root->state)) {
 		/* Want the extent tree to be the last on the list */
-		if (root->objectid == BTRFS_EXTENT_TREE_OBJECTID)
+		if (root->root_key.objectid == BTRFS_EXTENT_TREE_OBJECTID)
 			list_move_tail(&root->dirty_list,
 				       &fs_info->dirty_cowonly_roots);
 		else