nfs: Leave pages in the pagecache if readpage failed

The pagecache handles readpage failing by itself; it doesn't want
filesystems to remove pages from under it.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

fs/nfs/read.c

@@ -120,12 +120,8 @@ static void nfs_readpage_release(struct nfs_page *req, int error)
 	if (nfs_error_is_fatal_on_server(error) && error != -ETIMEDOUT)
 		SetPageError(page);
 	if (nfs_page_group_sync_on_bit(req, PG_UNLOCKPAGE)) {
-		struct address_space *mapping = page_file_mapping(page);
-
 		if (PageUptodate(page))
 			nfs_fscache_write_page(inode, page);
-		else if (!PageError(page) && !PagePrivate(page))
-			generic_error_remove_page(mapping, page);
 		unlock_page(page);
 	}
 	nfs_release_request(req);