f2fs: enforce fsync_mode=strict for renamed directory

This is to give a option for user to be able to recover B/foo in the below
case.

mkdir A
sync()
rename(A, B)
creat (B/foo)
fsync (B/foo)
---crash---
Sugessted-by: Velayudhan Pillai <vijay@cs.utexas.edu>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/namei.c

@@ -973,8 +973,11 @@ static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry,
 			f2fs_put_page(old_dir_page, 0);
 		f2fs_i_links_write(old_dir, false);
 	}
-	if (F2FS_OPTION(sbi).fsync_mode == FSYNC_MODE_STRICT)
+	if (F2FS_OPTION(sbi).fsync_mode == FSYNC_MODE_STRICT) {
 		add_ino_entry(sbi, new_dir->i_ino, TRANS_DIR_INO);
+		if (S_ISDIR(old_inode->i_mode))
+			add_ino_entry(sbi, old_inode->i_ino, TRANS_DIR_INO);
+	}
 
 	f2fs_unlock_op(sbi);