btrfs: use extent_io_tree_release() to empty dirty log pages

When freeing a log tree, during a transaction commit, we clear its dirty
log pages io tree by calling clear_extent_bits() using a range from 0 to
(u64)-1. This will iterate the io tree's rbtree and call rb_erase() on
each node before freeing it, which will often trigger rebalance operations
on the rbtree. A better alternative it to use extent_io_tree_release(),
which will not do deletions and trigger rebalances.

So use extent_io_tree_release() instead of clear_extent_bits().
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/tree-log.c

@@ -3208,8 +3208,7 @@ static void free_log_tree(struct btrfs_trans_handle *trans,
 		}
 	}
 
-	clear_extent_bits(&log->dirty_log_pages, 0, (u64)-1,
-			  EXTENT_DIRTY | EXTENT_NEW | EXTENT_NEED_WAIT);
+	extent_io_tree_release(&log->dirty_log_pages);
 	extent_io_tree_release(&log->log_csum_range);
 
 	btrfs_put_root(log);