f2fs: fix to clear CP_TRIMMED_FLAG

Once CP_TRIMMED_FLAG is set, after a reboot, we will never issue discard
before LBA becomes invalid again, fix it by clearing the flag in
checkpoint without CP_TRIMMED reason.

Fixes: 1f43e2ad ("f2fs: introduce CP_TRIMMED_FLAG to avoid unneeded discard")
Signed-off-by: NChao Yu <yuchao0@huawei.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/checkpoint.c

@@ -1136,6 +1136,8 @@ static void update_ckpt_flags(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 
 	if (cpc->reason & CP_TRIMMED)
 		__set_ckpt_flags(ckpt, CP_TRIMMED_FLAG);
+	else
+		__clear_ckpt_flags(ckpt, CP_TRIMMED_FLAG);
 
 	if (cpc->reason & CP_UMOUNT)
 		__set_ckpt_flags(ckpt, CP_UMOUNT_FLAG);