btrfs: remove log_extents_lock and logged_list from struct btrfs_root

The logged_list[2] and log_extents_lock[2] members of struct btrfs_root
are no longer used, their last use was removed in commit 5636cf7d
("btrfs: remove the logged extents infrastructure"). So remove these
fields. This reduces the size of struct btrfs_root, on a release kernel,
from 1392 bytes down to 1352 bytes.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/ctree.h

@@ -224,9 +224,6 @@ struct btrfs_root {
 
 	struct list_head root_list;
 
-	spinlock_t log_extents_lock[2];
-	struct list_head logged_list[2];
-
 	spinlock_t inode_lock;
 	/* red-black tree that keeps track of in-memory inodes */
 	struct rb_root inode_tree;

fs/btrfs/disk-io.c

@@ -650,14 +650,10 @@ static void __setup_root(struct btrfs_root *root, struct btrfs_fs_info *fs_info,
 	INIT_LIST_HEAD(&root->ordered_extents);
 	INIT_LIST_HEAD(&root->ordered_root);
 	INIT_LIST_HEAD(&root->reloc_dirty_list);
-	INIT_LIST_HEAD(&root->logged_list[0]);
-	INIT_LIST_HEAD(&root->logged_list[1]);
 	spin_lock_init(&root->inode_lock);
 	spin_lock_init(&root->delalloc_lock);
 	spin_lock_init(&root->ordered_extent_lock);
 	spin_lock_init(&root->accounting_lock);
-	spin_lock_init(&root->log_extents_lock[0]);
-	spin_lock_init(&root->log_extents_lock[1]);
 	spin_lock_init(&root->qgroup_meta_rsv_lock);
 	mutex_init(&root->objectid_mutex);
 	mutex_init(&root->log_mutex);