fs: remove some AOP_TRUNCATED_PAGE

prepare/commit_write no longer returns AOP_TRUNCATED_PAGE since OCFS2 and
GFS2 were converted to the new aops, so we can make some simplifications
for that.

[michal.k.k.piotrowski@gmail.com: fix warning]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Mark Fasheh <mark.fasheh@oracle.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Michal Piotrowski <michal.k.k.piotrowski@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 281c19f..6f8e16e 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -621,11 +621,7 @@
   	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