btrfs: memset cur_trans->delayed_refs to zero

Use memset() to null out the btrfs_delayed_ref_root of
btrfs_transaction instead of setting all the members to 0 by hand.
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NAlexandru Moise <00moses.alexander00@gmail.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/transaction.c

@@ -236,15 +236,11 @@ static noinline int join_transaction(struct btrfs_root *root, unsigned int type)
 	cur_trans->start_time = get_seconds();
 	cur_trans->dirty_bg_run = 0;
 
+	memset(&cur_trans->delayed_refs, 0, sizeof(cur_trans->delayed_refs));
+
 	cur_trans->delayed_refs.href_root = RB_ROOT;
 	cur_trans->delayed_refs.dirty_extent_root = RB_ROOT;
 	atomic_set(&cur_trans->delayed_refs.num_entries, 0);
-	cur_trans->delayed_refs.num_heads_ready = 0;
-	cur_trans->delayed_refs.pending_csums = 0;
-	cur_trans->delayed_refs.num_heads = 0;
-	cur_trans->delayed_refs.flushing = 0;
-	cur_trans->delayed_refs.run_delayed_start = 0;
-	cur_trans->delayed_refs.qgroup_to_skip = 0;
 
 	/*
 	 * although the tree mod log is per file system and not per transaction,