f2fs: handle unallocated section and zone on pinned/atgc

If we have large section/zone, unallocated segment makes them corrupted.

E.g.,

  - Pinned file:       -1 119304647 119304647
  - ATGC   data:       -1 119304647 119304647
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/segment.h

@@ -101,11 +101,11 @@ static inline void sanity_check_seg_type(struct f2fs_sb_info *sbi,
 #define BLKS_PER_SEC(sbi)					\
 	((sbi)->segs_per_sec * (sbi)->blocks_per_seg)
 #define GET_SEC_FROM_SEG(sbi, segno)				\
-	((segno) / (sbi)->segs_per_sec)
+	(((segno) == -1) ? -1: (segno) / (sbi)->segs_per_sec)
 #define GET_SEG_FROM_SEC(sbi, secno)				\
 	((secno) * (sbi)->segs_per_sec)
 #define GET_ZONE_FROM_SEC(sbi, secno)				\
-	((secno) / (sbi)->secs_per_zone)
+	(((secno) == -1) ? -1: (secno) / (sbi)->secs_per_zone)
 #define GET_ZONE_FROM_SEG(sbi, segno)				\
 	GET_ZONE_FROM_SEC(sbi, GET_SEC_FROM_SEG(sbi, segno))