I have the following question regarding the linux file system implementation.

In linux/fs.h I saw the "struct super_operation" structure. I saw that two of the member function pointers are write_inode() and put_inode(). But In the ext2,ext3,ext4 implementation i saw that it uses the only write_inode() function. So, what is the reason behind keeping the other pointers ?

With Regards
Dibyayan Chakraborty