blkback-blkif-flush.diff

blkback: Flush bdev during close and open.

Open, so outstanding buffer I/O is flushed.
Close, so that stale buffers are reread.

Signed-off-by: Daniel Stodden <daniel.stodden@citrix.com>

diff -r 8bafdb313b79 drivers/xen/blkback/blkback.c
--- a/drivers/xen/blkback/blkback.c	Sun May 23 02:00:46 2010 -0700
+++ b/drivers/xen/blkback/blkback.c	Sun May 23 02:00:55 2010 -0700
@@ -117,6 +117,17 @@
 static void make_response(blkif_t *blkif, u64 id,
 			  unsigned short op, int st);
 
+static int
+blkif_bdev_flush(blkif_t *blkif)
+{
+	int err = -EBADF;
+
+	if (blkif->bdev)
+		err = ioctl_by_bdev(blkif->bdev, BLKFLSBUF, 0);
+
+	return err;
+}
+
 int
 blkif_bdev_open(blkif_t *blkif, dev_t dev, int mode, int cdrom)
 {
@@ -133,6 +144,8 @@
 	blkif->cdrom = cdrom;
 	blkif->bdev  = bdev;
 
+	blkif_bdev_flush(blkif);
+
 	return 0;
 }
 
@@ -142,6 +155,8 @@
 	struct block_device *bdev = blkif->bdev;
 
 	if (bdev) {
+		blkif_bdev_flush(blkif);
+
 		blkdev_put(bdev);
 		blkif->bdev = NULL;
 	}
diff -r 8bafdb313b79 drivers/xen/blkback/xenbus.c
--- a/drivers/xen/blkback/xenbus.c	Sun May 23 02:00:46 2010 -0700
+++ b/drivers/xen/blkback/xenbus.c	Sun May 23 02:00:55 2010 -0700
@@ -99,13 +99,6 @@
 		return;
 	}
 
-	err = filemap_write_and_wait(blkif->bdev->bd_inode->i_mapping);
-	if (err) {
-		xenbus_dev_error(blkif->be->dev, err, "block flush");
-		return;
-	}
-	invalidate_inode_pages2(blkif->bdev->bd_inode->i_mapping);
-
 	blkif->xenblkd = kthread_run(blkif_schedule, blkif, name);
 	if (IS_ERR(blkif->xenblkd)) {
 		err = PTR_ERR(blkif->xenblkd);