blkback: Flush blkback data when connecting.

First cut at flushing blkback data when first connecting
blkback.  This should avoid the pygrub issues we are experiencing
in (RedHat bugzilla) 466681.

Signed-off-by: Chris Lalancette <clalance@redhat.com>

diff --git a/drivers/xen/blkback/xenbus.c b/drivers/xen/blkback/xenbus.c
index 6a5669e9292b60e1d2fa1de7a6db9153010e9329..82fa267c616d09df66f6798f16f2f36729ef82ad 100644 (file)
--- a/drivers/xen/blkback/xenbus.c
+++ b/drivers/xen/blkback/xenbus.c
@@ -88,6 +88,13 @@ static void update_blkif_status(blkif_t *blkif)
                return;
        }
 
+       err = filemap_write_and_wait(blkif->vbd.bdev->bd_inode->i_mapping);
+       if (err) {
+               xenbus_dev_error(blkif->be->dev, err, "block flush");
+               return;
+       }
+       invalidate_inode_pages2(blkif->vbd.bdev->bd_inode->i_mapping);
+
        blkif->xenblkd = kthread_run(blkif_schedule, blkif, name);
        if (IS_ERR(blkif->xenblkd)) {
                err = PTR_ERR(blkif->xenblkd);