[PATCH] don't clear PG_uptodate on ENOSPC

If get_block() returns -ENOSPC __block_write_full_page() is currently
clearing PG_uptodate.

Tht doesn't make any sense - failure to allocate space (or an IO error) does
not make the page not uptodate.  It will create pages which are dirty, mapped
into pagetables and not uptodate, which is a nonsensical state.

fs/buffer.c

@@ -1754,7 +1754,6 @@ static int __block_write_full_page(struct inode *inode, struct page *page,
 	 * exposing stale data.
 	 * The page is currently locked and not marked for writeback
 	 */
-	ClearPageUptodate(page);
 	bh = head;
 	/* Recovery: lock and submit the mapped buffers */
 	do {