9p: Add a Direct IO support for non-cached operations.

	return 0;

}

/**

 * v9fs_direct_IO - 9P address space operation for direct I/O

 * @rw: direction (read or write)

 * @iocb: target I/O control block

 * @iov: array of vectors that define I/O buffer

 * @pos: offset in file to begin the operation

 * @nr_segs: size of iovec array

 *

 * The presence of v9fs_direct_IO() in the address space ops vector

 * allowes open() O_DIRECT flags which would have failed otherwise.

 *

 * In the non-cached mode, we shunt off direct read and write requests before

 * the VFS gets them, so this method should never be called.

 *

 * Direct IO is not 'yet' supported in the cached mode. Hence when

 * this routine is called through generic_file_aio_read(), the read/write fails

 * with an error.

 *

 */

ssize_t v9fs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,

		loff_t pos, unsigned long nr_segs)

{

	P9_DPRINTK(P9_DEBUG_VFS, "v9fs_direct_IO: v9fs_direct_IO (%s) "

			"off/no(%lld/%lu) EINVAL\n",

			iocb->ki_filp->f_path.dentry->d_name.name,

			(long long) pos, nr_segs);

	return -EINVAL;

}

const struct address_space_operations v9fs_addr_operations = {

      .readpage = v9fs_vfs_readpage,

      .readpages = v9fs_vfs_readpages,

      .releasepage = v9fs_release_page,

      .invalidatepage = v9fs_invalidate_page,

      .launder_page = v9fs_launder_page,

      .direct_IO = v9fs_direct_IO,

};