wait_on_page_writeback_range shouldn't wait for pages beyond the specified
range.  Ideally, the radix-tree-lookup could accept an end_index parameter so
that it doesn't return the extra pages in the first place, but for now we just
add a few extra checks to skip such pages.
Signed-off-by: Suparna Bhattacharya <suparna@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>