any basic-blocks on storage, then those blocks should be
pre-read (if they haven't been read already) so that the
updated blocks can be written out properly.
- The page will be locked. If prepare_write wants to unlock the
- page it, like readpage, may do so and return
- AOP_TRUNCATED_PAGE.
- In this case the prepare_write will be retried one the lock is
- regained.
+ The page will be locked.
Note: the page _must not_ be marked uptodate in this function
(or anywhere else) unless it actually is uptodate right now. As
wants to make it a free page. If ->releasepage succeeds, the
page will be removed from the address_space and become free.
- The second case if when a request has been made to invalidate
+ The second case is when a request has been made to invalidate
some or all pages in an address_space. This can happen
through the fadvice(POSIX_FADV_DONTNEED) system call or by the
filesystem explicitly requesting it as nfs and 9fs do (when