bh->b_data contains the buffer data in linux kernel where bh is pointer to buffer_head structure in linux kernel -2.6.26.

when cp is performed block_commit_write function is called which write the data block.cp stores the data in buffer cache

When mmap is performed mpage_writepage is called here i want to know which data structure stores the content of page.mmap stores the data DIRECTLY INTO THE PAGE CACHE.