f2fs: skip migration only when BG_GC is called

FG_GC needs to move entire section more quickly.
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/gc.c

@@ -1211,7 +1211,7 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
 
 		if (get_valid_blocks(sbi, segno, false) == 0)
 			goto freed;
-		if (__is_large_section(sbi) &&
+		if (gc_type == BG_GC && __is_large_section(sbi) &&
 				migrated >= sbi->migration_granularity)
 			goto skip;
 		if (!PageUptodate(sum_page) || unlikely(f2fs_cp_error(sbi)))