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Commit f0973863 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Nathan Scott
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[XFS] Delay direct I/O completion to a workqueue This is nessecary 


because aio+dio completions may happen from irq context but we need
process context for converting unwritten extents.  We also queue regular
direct I/O completions to workqueue for regularity, there's only one
queue_work call per syscall.

SGI-PV: 934766
SGI-Modid: xfs-linux:xfs-kern:196857a

Signed-off-by: default avatarChristoph Hellwig <hch@sgi.com>
Signed-off-by: default avatarNathan Scott <nathans@sgi.com>
parent 65b3da37

fs/xfs/linux-2.6/xfs_aops.c

+48 −26
Original line number Diff line number Diff line
@@ -126,7 +126,7 @@ xfs_destroy_ioend( 


/*

 * Issue transactions to convert a buffer range from unwritten

 * to written extents (buffered IO).

 * to written extents.

 */

STATIC void

xfs_end_bio_unwritten(
@@ -191,29 +191,6 @@ linvfs_unwritten_done( 
	end_buffer_async_write(bh, uptodate);

}



/*

 * Issue transactions to convert a buffer range from unwritten

 * to written extents (direct IO).

 */

STATIC void

linvfs_unwritten_convert_direct(

	struct kiocb	*iocb,

	loff_t		offset,

	ssize_t		size,

	void		*private)

{

	struct inode	*inode = iocb->ki_filp->f_dentry->d_inode;

	ASSERT(!private || inode == (struct inode *)private);



	/* private indicates an unwritten extent lay beneath this IO */

	if (private && size > 0) {

		vnode_t	*vp = LINVFS_GET_VP(inode);

		int	error;



		VOP_BMAP(vp, offset, size, BMAPI_UNWRITTEN, NULL, NULL, error);

	}

}



STATIC int

xfs_map_blocks(

	struct inode		*inode,
@@ -1045,6 +1022,44 @@ linvfs_get_blocks_direct( 
					create, 1, BMAPI_WRITE|BMAPI_DIRECT);

}



STATIC void

linvfs_end_io_direct(

	struct kiocb	*iocb,

	loff_t		offset,

	ssize_t		size,

	void		*private)

{

	xfs_ioend_t	*ioend = iocb->private;



	/*

	 * Non-NULL private data means we need to issue a transaction to

	 * convert a range from unwritten to written extents.  This needs

	 * to happen from process contect but aio+dio I/O completion

	 * happens from irq context so we need to defer it to a workqueue.

	 * This is not nessecary for synchronous direct I/O, but we do

	 * it anyway to keep the code uniform and simpler.

	 *

	 * The core direct I/O code might be changed to always call the

	 * completion handler in the future, in which case all this can

	 * go away.

	 */

	if (private && size > 0) {

		ioend->io_offset = offset;

		ioend->io_size = size;

		xfs_finish_ioend(ioend);

	} else {

		ASSERT(size >= 0);

		xfs_destroy_ioend(ioend);

	}



	/*

	 * blockdev_direct_IO can return an error even afer the I/O

	 * completion handler was called.  Thus we need to protect

	 * against double-freeing.

	 */

	iocb->private = NULL;

}



STATIC ssize_t

linvfs_direct_IO(

	int			rw,
@@ -1059,16 +1074,23 @@ linvfs_direct_IO( 
	xfs_iomap_t	iomap;

	int		maps = 1;

	int		error;

	ssize_t		ret;



	VOP_BMAP(vp, offset, 0, BMAPI_DEVICE, &iomap, &maps, error);

	if (error)

		return -error;



	return blockdev_direct_IO_own_locking(rw, iocb, inode,

	iocb->private = xfs_alloc_ioend(inode);



	ret = blockdev_direct_IO_own_locking(rw, iocb, inode,

		iomap.iomap_target->pbr_bdev,

		iov, offset, nr_segs,

		linvfs_get_blocks_direct,

		linvfs_unwritten_convert_direct);

		linvfs_end_io_direct);



	if (unlikely(ret <= 0 && iocb->private))

		xfs_destroy_ioend(iocb->private);

	return ret;

}

fs/xfs/linux-2.6/xfs_lrw.c

+0 −3
Original line number Diff line number Diff line
@@ -660,9 +660,6 @@ xfs_write( 
			(xip->i_d.di_flags & XFS_DIFLAG_REALTIME) ?

				mp->m_rtdev_targp : mp->m_ddev_targp;



		if (ioflags & IO_ISAIO)

			return XFS_ERROR(-ENOSYS);



		if ((pos & target->pbr_smask) || (count & target->pbr_smask))

			return XFS_ERROR(-EINVAL);