ANDROID: sdcardfs: support direct-IO (DIO) operations

		struct iov_iter *iter, loff_t pos)

{

	/*

     * This function returns zero on purpose in order to support direct IO.

	 * __dentry_open checks a_ops->direct_IO and returns EINVAL if it is null.

     *

	 * However, this function won't be called by certain file operations

     * including generic fs functions.  * reads and writes are delivered to

     * the lower file systems and the direct IOs will be handled by them.

	 *

     * NOTE: exceptionally, on the recent kernels (since Linux 3.8.x),

     * swap_writepage invokes this function directly.

	 * This function should never be called directly.  We need it

	 * to exist, to get past a check in open_check_o_direct(),

	 * which is called from do_last().

	 */

	printk(KERN_INFO "%s, operation is not supported\n", __func__);

	return 0;

	return -EINVAL;

}

/*

 * XXX: the default address_space_ops for sdcardfs is empty.  We cannot set

 * our inode->i_mapping->a_ops to NULL because too many code paths expect

 * the a_ops vector to be non-NULL.

 */

const struct address_space_operations sdcardfs_aops = {

	/* empty on purpose */

	.direct_IO	= sdcardfs_direct_IO,

};

#include <linux/dcache.h>

#include <linux/file.h>

#include <linux/fs.h>

#include <linux/aio.h>

#include <linux/mm.h>

#include <linux/mount.h>

#include <linux/namei.h>