From: Christoph Hellwig <hch@infradead.org>

Date: Sun, 18 Jul 2010 21:17:10 +0000 (+0000)

Subject: xfs: move aio completion after unwritten extent conversion

X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=fb511f2150174b18b28ad54708c1adda0df39b17

xfs: move aio completion after unwritten extent conversion

If we write into an unwritten extent using AIO we need to complete the AIO

request after the extent conversion has finished.  Without that a read could

race to see see the extent still unwritten and return zeros.   For synchronous

I/O we already take care of that by flushing the xfsconvertd workqueue (which

might be a bit of overkill).

To do that add iocb and result fields to struct xfs_ioend, so that we can

call aio_complete from xfs_end_io after the extent conversion has happened.

Note that we need a new result field as io_error is used for positive errno

values, while the AIO code can return negative error values and positive

transfer sizes.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: Dave Chinner <dchinner@redhat.com>

Signed-off-by: Alex Elder <aelder@sgi.com>

---

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c

index 95d1e26..13622d5 100644

--- a/fs/xfs/linux-2.6/xfs_aops.c

+++ b/fs/xfs/linux-2.6/xfs_aops.c

@@ -265,8 +265,11 @@ xfs_end_io(

 		xfs_finish_ioend(ioend, 0);

 		/* ensure we don't spin on blocked ioends */

 		delay(1);

-	} else

+	} else {

+		if (ioend->io_iocb)

+			aio_complete(ioend->io_iocb, ioend->io_result, 0);

 		xfs_destroy_ioend(ioend);

+	}

 }

 /*

@@ -299,6 +302,8 @@ xfs_alloc_ioend(

 	atomic_inc(&XFS_I(ioend->io_inode)->i_iocount);

 	ioend->io_offset = 0;

 	ioend->io_size = 0;

+	ioend->io_iocb = NULL;

+	ioend->io_result = 0;

 	INIT_WORK(&ioend->io_work, xfs_end_io);

 	return ioend;

@@ -1411,6 +1416,7 @@ xfs_end_io_direct(

 	bool		is_async)

 {

 	xfs_ioend_t	*ioend = iocb->private;

+	bool		complete_aio = is_async;

 	/*

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

@@ -1436,7 +1442,14 @@ xfs_end_io_direct(

 	if (ioend->io_type == IO_READ) {

 		xfs_finish_ioend(ioend, 0);

 	} else if (private && size > 0) {

-		xfs_finish_ioend(ioend, is_sync_kiocb(iocb));

+		if (is_async) {

+			ioend->io_iocb = iocb;

+			ioend->io_result = ret;

+			complete_aio = false;

+			xfs_finish_ioend(ioend, 0);

+		} else {

+			xfs_finish_ioend(ioend, 1);

+		}

 	} else {

 		/*

 		 * A direct I/O write ioend starts it's life in unwritten

@@ -1455,7 +1468,7 @@ xfs_end_io_direct(

 	 */

 	iocb->private = NULL;

-	if (is_async)

+	if (complete_aio)

 		aio_complete(iocb, ret, 0);

 }