f2fs: return error during fill_super

Let's avoid BUG_ON during fill_super, when on-disk was totall corrupted.

Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index d1d394c..71a2aaa 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -655,7 +655,7 @@ static inline void verify_block_addr(struct f2fs_sb_info *sbi, block_t blk_addr)
 /*
  * Summary block is always treated as an invalid block
  */
-static inline void check_block_count(struct f2fs_sb_info *sbi,
+static inline int check_block_count(struct f2fs_sb_info *sbi,
 		int segno, struct f2fs_sit_entry *raw_sit)
 {
 #ifdef CONFIG_F2FS_CHECK_FS
@@ -677,11 +677,25 @@ static inline void check_block_count(struct f2fs_sb_info *sbi,
 		cur_pos = next_pos;
 		is_valid = !is_valid;
 	} while (cur_pos < sbi->blocks_per_seg);
-	BUG_ON(GET_SIT_VBLOCKS(raw_sit) != valid_blocks);
+
+	if (unlikely(GET_SIT_VBLOCKS(raw_sit) != valid_blocks)) {
+		f2fs_msg(sbi->sb, KERN_ERR,
+				"Mismatch valid blocks %d vs. %d",
+					GET_SIT_VBLOCKS(raw_sit), valid_blocks);
+		set_sbi_flag(sbi, SBI_NEED_FSCK);
+		return -EINVAL;
+	}
 #endif
 	/* check segment usage, and check boundary of a given segment number */
-	f2fs_bug_on(sbi, GET_SIT_VBLOCKS(raw_sit) > sbi->blocks_per_seg
-					|| segno > TOTAL_SEGS(sbi) - 1);
+	if (unlikely(GET_SIT_VBLOCKS(raw_sit) > sbi->blocks_per_seg
+					|| segno > TOTAL_SEGS(sbi) - 1)) {
+		f2fs_msg(sbi->sb, KERN_ERR,
+				"Wrong valid blocks %d or segno %u",
+					GET_SIT_VBLOCKS(raw_sit), segno);
+		set_sbi_flag(sbi, SBI_NEED_FSCK);
+		return -EINVAL;
+	}
+	return 0;
 }
 
 static inline pgoff_t current_sit_addr(struct f2fs_sb_info *sbi,