f2fs: give a chance to detach from dirty list

If there is no dirty pages in inode, we should give a chance to detach
the inode from global dirty list, otherwise it needs to call another
unnecessary .writepages for detaching.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/gc.c

@@ -673,8 +673,10 @@ static void move_data_page(struct inode *inode, block_t bidx, int gc_type)
 retry:
 		set_page_dirty(page);
 		f2fs_wait_on_page_writeback(page, DATA, true);
-		if (clear_page_dirty_for_io(page))
+		if (clear_page_dirty_for_io(page)) {
 			inode_dec_dirty_pages(inode);
+			remove_dirty_inode(inode);
+		}
 
 		set_cold_data(page);