[patch] xen-blkback: sync I/O after backend disconnected

[Joe Jin <joe.jin@oracle.com>]

When backend disconnect, sync IO requests to the disk.

Signed-off-by: Joe Jin <joe.jin@oracle.com>
Cc: Jens Axboe <jaxboe@fusionio.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Ian Campbell <Ian.Campbell@eu.citrix.com>
---
 drivers/block/xen-blkback/xenbus.c |    8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 1a87f5b..da39d61 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -35,6 +35,7 @@ static void connect(struct backend_info *);
 static int connect_ring(struct backend_info *);
 static void backend_changed(struct xenbus_watch *, const char **,
 			    unsigned int);
+static void xen_vbd_sync(struct xen_vbd *vbd);
 
 struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be)
 {
@@ -232,6 +233,7 @@ static void xen_blkif_disconnect(struct xen_blkif *blkif)
 		free_vm_area(blkif->blk_ring_area);
 		blkif->blk_rings.common.sring = NULL;
 	}
+	xen_vbd_sync(&blkif->vbd);
 }
 
 void xen_blkif_free(struct xen_blkif *blkif)
@@ -332,6 +334,12 @@ static void xen_vbd_free(struct xen_vbd *vbd)
 	vbd->bdev = NULL;
 }
 
+static void xen_vbd_sync(struct xen_vbd *vbd)
+{
+	if (vbd->bdev)
+		fsync_bdev(vbd->bdev);
+}
+
 static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle,
 			  unsigned major, unsigned minor, int readonly,
 			  int cdrom)