From: NeilBrown <neilb@cse.unsw.edu.au>

There is severe bit-rot in this code, which is to say that it doesn't work
at all: an io error during read will do bad things.  It should work better
with this patch.
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>