[PATCH] Make address_space_operations->invalidatepage return void

The return value of this function is never used, so let's be honest and
declare it as void.

Some places where invalidatepage returned 0, I have inserted comments
suggesting a BUG_ON.

[akpm@osdl.org: JBD BUG fix]
[akpm@osdl.org: rework for git-nfs]
[akpm@osdl.org: don't go BUG in block_invalidate_page()]
Signed-off-by: Neil Brown <neilb@suse.de>
Acked-by: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index 27dd97b..da917ed 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -189,8 +189,8 @@
  * address_spaces.
  */
 int try_to_release_page(struct page * page, gfp_t gfp_mask);
-int block_invalidatepage(struct page *page, unsigned long offset);
-int do_invalidatepage(struct page *page, unsigned long offset);
+void block_invalidatepage(struct page *page, unsigned long offset);
+void do_invalidatepage(struct page *page, unsigned long offset);
 int block_write_full_page(struct page *page, get_block_t *get_block,
 				struct writeback_control *wbc);
 int block_read_full_page(struct page*, get_block_t*);