struct seg_entry *sentry = get_seg_entry(sbi, segno);
                enum dirty_type t = sentry->type;
 
+               if (unlikely(t >= DIRTY)) {
+                       f2fs_bug_on(sbi, 1);
+                       return;
+               }
                if (!test_and_set_bit(segno, dirty_i->dirty_segmap[t]))
                        dirty_i->nr_dirty[t]++;
        }
                        break;
                offset = segno + 1;
                valid_blocks = get_valid_blocks(sbi, segno, 0);
-               if (valid_blocks >= sbi->blocks_per_seg || !valid_blocks)
+               if (valid_blocks == sbi->blocks_per_seg || !valid_blocks)
                        continue;
+               if (valid_blocks > sbi->blocks_per_seg) {
+                       f2fs_bug_on(sbi, 1);
+                       continue;
+               }
                mutex_lock(&dirty_i->seglist_lock);
                __locate_dirty_segment(sbi, segno, DIRTY);
                mutex_unlock(&dirty_i->seglist_lock);