f2fs_flush_merged_bios(sbi);
 
+       /* this is the case of multiple fstrims without any changes */
+       if (cpc->reason == CP_DISCARD && !is_sbi_flag_set(sbi, SBI_IS_DIRTY)) {
+               f2fs_bug_on(sbi, NM_I(sbi)->dirty_nat_cnt);
+               f2fs_bug_on(sbi, SIT_I(sbi)->dirty_sentries);
+               f2fs_bug_on(sbi, prefree_segments(sbi));
+               flush_sit_entries(sbi, cpc);
+               clear_prefree_segments(sbi, cpc);
+               unblock_operations(sbi);
+               goto out;
+       }
+
        /*
         * update checkpoint pack index
         * Increase the version number so that