suse man page for write_cache_pages

WRITE_CACHE_PAGES(9)					    Memory Management in Linux					      WRITE_CACHE_PAGES(9)

NAME
       write_cache_pages - walk the list of dirty pages of the given address space and write all of them.

SYNOPSIS
       int write_cache_pages(struct address_space * mapping, struct writeback_control * wbc, writepage_t writepage, void * data);

ARGUMENTS
       mapping
	   address space structure to write

       wbc
	   subtract the number of written pages from *wbc->nr_to_write

       writepage
	   function called for each page

       data
	   data passed to writepage function

DESCRIPTION
       If a page is already under I/O, write_cache_pages skips it, even if it's dirty. This is desirable behaviour for memory-cleaning writeback,
       but it is INCORRECT for data-integrity system calls such as fsync.  fsync and msync need to guarantee that all the data which was dirty at
       the time the call was made get new I/O started against them. If wbc->sync_mode is WB_SYNC_ALL then we were called for data integrity and we
       must wait for existing IO to complete.

COPYRIGHT
Kernel Hackers Manual 2.6.					     July 2010						      WRITE_CACHE_PAGES(9)