Commit bbc5a740 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Dave Chinner
Browse files

xfs: split xfs_file_read_iter into buffered and direct I/O helpers 



Similar to what we did on the write side a while ago.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
parent cf810712

fs/xfs/xfs_file.c

+57 −26
Original line number Diff line number Diff line
@@ -282,35 +282,33 @@ xfs_file_fsync( 
}



STATIC ssize_t

xfs_file_read_iter(

xfs_file_dio_aio_read(

	struct kiocb		*iocb,

	struct iov_iter		*to)

{

	struct file		*file = iocb->ki_filp;

	struct inode		*inode = file->f_mapping->host;

	struct address_space	*mapping = iocb->ki_filp->f_mapping;

	struct inode		*inode = mapping->host;

	struct xfs_inode	*ip = XFS_I(inode);

	struct xfs_mount	*mp = ip->i_mount;

	size_t			size = iov_iter_count(to);

	size_t			count = iov_iter_count(to);

	struct xfs_buftarg	*target;

	ssize_t			ret = 0;

	loff_t			pos = iocb->ki_pos;



	XFS_STATS_INC(mp, xs_read_calls);

	trace_xfs_file_direct_read(ip, count, iocb->ki_pos);



	if ((iocb->ki_flags & IOCB_DIRECT) && !IS_DAX(inode)) {

		xfs_buftarg_t	*target =

			XFS_IS_REALTIME_INODE(ip) ?

				mp->m_rtdev_targp : mp->m_ddev_targp;

	if (XFS_IS_REALTIME_INODE(ip))

		target = ip->i_mount->m_rtdev_targp;

	else

		target = ip->i_mount->m_ddev_targp;



	if (!IS_DAX(inode)) {

		/* DIO must be aligned to device logical sector size */

		if ((pos | size) & target->bt_logical_sectormask) {

			if (pos == i_size_read(inode))

		if ((iocb->ki_pos | count) & target->bt_logical_sectormask) {

			if (iocb->ki_pos == i_size_read(inode))

				return 0;

			return -EINVAL;

		}

	}



	if (XFS_FORCED_SHUTDOWN(mp))

		return -EIO;



	/*

	 * Locking is a bit tricky here. If we take an exclusive lock for direct

	 * IO, we effectively serialise all new concurrent read IO to this file
@@ -322,7 +320,7 @@ xfs_file_read_iter( 
	 * serialisation.

	 */

	xfs_rw_ilock(ip, XFS_IOLOCK_SHARED);

	if ((iocb->ki_flags & IOCB_DIRECT) && inode->i_mapping->nrpages) {

	if (mapping->nrpages) {

		xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);

		xfs_rw_ilock(ip, XFS_IOLOCK_EXCL);
@@ -337,8 +335,8 @@ xfs_file_read_iter( 
		 * flush and reduce the chances of repeated iolock cycles going

		 * forward.

		 */

		if (inode->i_mapping->nrpages) {

			ret = filemap_write_and_wait(VFS_I(ip)->i_mapping);

		if (mapping->nrpages) {

			ret = filemap_write_and_wait(mapping);

			if (ret) {

				xfs_rw_iunlock(ip, XFS_IOLOCK_EXCL);

				return ret;
@@ -349,23 +347,56 @@ xfs_file_read_iter( 
			 * we fail to invalidate a page, but this should never

			 * happen on XFS. Warn if it does fail.

			 */

			ret = invalidate_inode_pages2(VFS_I(ip)->i_mapping);

			ret = invalidate_inode_pages2(mapping);

			WARN_ON_ONCE(ret);

			ret = 0;

		}

		xfs_rw_ilock_demote(ip, XFS_IOLOCK_EXCL);

	}



	ret = generic_file_read_iter(iocb, to);

	xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);



	return ret;

}



STATIC ssize_t

xfs_file_buffered_aio_read(

	struct kiocb		*iocb,

	struct iov_iter		*to)

{

	struct xfs_inode	*ip = XFS_I(file_inode(iocb->ki_filp));

	ssize_t			ret;



	trace_xfs_file_buffered_read(ip, iov_iter_count(to), iocb->ki_pos);



	xfs_rw_ilock(ip, XFS_IOLOCK_SHARED);

	ret = generic_file_read_iter(iocb, to);

	xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);



	return ret;

}



STATIC ssize_t

xfs_file_read_iter(

	struct kiocb		*iocb,

	struct iov_iter		*to)

{

	struct xfs_mount	*mp = XFS_I(file_inode(iocb->ki_filp))->i_mount;

	ssize_t			ret = 0;



	XFS_STATS_INC(mp, xs_read_calls);



	if (XFS_FORCED_SHUTDOWN(mp))

		return -EIO;



	if (iocb->ki_flags & IOCB_DIRECT)

		trace_xfs_file_direct_read(ip, size, pos);

		ret = xfs_file_dio_aio_read(iocb, to);

	else

		trace_xfs_file_buffered_read(ip, size, pos);

		ret = xfs_file_buffered_aio_read(iocb, to);



	ret = generic_file_read_iter(iocb, to);

	if (ret > 0)

		XFS_STATS_ADD(mp, xs_read_bytes, ret);



	xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);

	return ret;

}
@@ -747,7 +778,7 @@ xfs_file_dio_aio_write( 
	end = iocb->ki_pos + count - 1;



	/*

	 * See xfs_file_read_iter() for why we do a full-file flush here.

	 * See xfs_file_dio_aio_read() for why we do a full-file flush here.

	 */

	if (mapping->nrpages) {

		ret = filemap_write_and_wait(VFS_I(ip)->i_mapping);