Don't do partial completions but instead acknowledge already transferred
sectors with verified good status on error.  This allows us to complete
"good" sectors to block layer even if bio they belong to wasn't finished
and simplifies code.
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@elka.pw.edu.pl>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>