Provided by:
linux-doc-2.6.15_2.6.15-23.39_all 
NAME
block_invalidatepage - invalidate part of all of a buffer-backed page
SYNOPSIS
int block_invalidatepage (struct page * page, unsigned long offset);
ARGUMENTS
page the page which is affected
offset the index of the truncation point
DESCRIPTION
block_invalidatepage is called when all or part of the page has become
invalidatedby a truncate operation.
block_invalidatepage does not have to release all buffers, but it must
ensure that no dirty buffer is left outside offset and that no I/O is
underway against any of the blocks which are outside the truncation
point. Because the caller is about to free (and possibly reuse) those
blocks on-disk.
DESCRIPTION
block_invalidatepage is called when all or part of the page has become
invalidatedby a truncate operation.
block_invalidatepage does not have to release all buffers, but it must
ensure that no dirty buffer is left outside offset and that no I/O is
underway against any of the blocks which are outside the truncation
point. Because the caller is about to free (and possibly reuse) those
blocks on-disk.