Writing out a (file) mmapped page

[Martin Jambor <jamborm@gmail.com>]

Hi,

I have spent a few hours trying to find out how dirty mmapped pages
are written out in filesystems using the "generic" functions but so
far I have not been successful. The main thing that escapes me is the
following:

block_write_full_page() writes out only buffers marked dirty or whole
page when there are no buffers associated with it. Where in kernel are
buffers either marked dirty or stripped off a mmaped page when the
page itself becomes dirty?  I would be very grateful for a pointer to
the source, possibly accompanied by a brief explanation of how it gets
called.

One comment in buffer.c suggests aops->prepare_write is called by a
pagefault handler for mmaped pages but I found no such call (using
cscope).

Thank you very much for any comment on this,

Martin Jambor