[PATCH] ufs: handle truncated pages

ufs_get_locked_page is called twice in ufs code, one time in ufs_truncate
path(we allocated last block), and another time when fragments are
reallocated.  In ideal world in the second case on allocation/free block
layer we should not know that things like `truncate' exists, but now with
such crutch like ufs_get_locked_page we can (or should?) skip truncated
pages.

Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>