f2fs: call f2fs_balance_fs only when node was changed

If user tries to update or read data, we don't need to call f2fs_balance_fs
which triggers f2fs_gc, which increases unnecessary long latency.

Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
index 8090854..c24e5d9 100644
--- a/fs/f2fs/inline.c
+++ b/fs/f2fs/inline.c
@@ -202,6 +202,10 @@
 	f2fs_unlock_op(sbi);
 
 	f2fs_put_page(page, 1);
+
+	if (dn.node_changed)
+		f2fs_balance_fs(sbi);
+
 	return err;
 }