blkback-bdev-reopen.diff

diff -r ef38bea97f71 drivers/xen/blkback/blkback.c
--- a/drivers/xen/blkback/blkback.c	Thu Jun 24 22:40:32 2010 -0700
+++ b/drivers/xen/blkback/blkback.c	Thu Jun 24 22:46:10 2010 -0700
@@ -140,6 +140,7 @@
 	if (IS_ERR(bdev))
 		return PTR_ERR(bdev);
 
+	blkif->dev   = dev;
 	blkif->mode  = mode;
 	blkif->cdrom = cdrom;
 	blkif->bdev  = bdev;
@@ -149,6 +150,18 @@
 	return 0;
 }
 
+int
+blkif_bdev_reopen(blkif_t *blkif)
+{
+	if (!blkif->dev)
+		return -ENODEV;
+
+	return blkif_bdev_open(blkif,
+			       blkif->dev,
+			       blkif->mode,
+			       blkif->cdrom);
+}
+
 void
 blkif_bdev_close(blkif_t *blkif)
 {
diff -r ef38bea97f71 drivers/xen/blkback/common.h
--- a/drivers/xen/blkback/common.h	Thu Jun 24 22:40:32 2010 -0700
+++ b/drivers/xen/blkback/common.h	Thu Jun 24 22:46:10 2010 -0700
@@ -78,6 +78,7 @@
 
 	/* The block device attached to this interface. */
 	struct block_device *bdev;
+	dev_t                dev;
 	int                  mode;
 	int                  cdrom;
 
@@ -123,6 +124,7 @@
 
 int blkif_bdev_open(blkif_t *blkif, dev_t dev, int mode, int cdrom);
 void blkif_bdev_close(blkif_t *blkif);
+int blkif_bdev_reopen(blkif_t *blkif);
 sector_t blkif_size(blkif_t *blkif);
 int blkif_sector_size(blkif_t *blkif);
 unsigned int blkif_info(blkif_t *blkif);
diff -r ef38bea97f71 drivers/xen/blkback/xenbus.c
--- a/drivers/xen/blkback/xenbus.c	Thu Jun 24 22:40:32 2010 -0700
+++ b/drivers/xen/blkback/xenbus.c	Thu Jun 24 22:46:10 2010 -0700
@@ -601,6 +601,24 @@
 	return 0;
 }
 
+static void
+blkback_reopen_bdev(struct backend_info *be)
+{
+	struct xenbus_device *xbdev = be->dev;
+	blkif_t *blkif = be->blkif;
+	int err;
+
+	if (blkif->bdev)
+		return;
+
+	if (xenbus_exists(XBT_NIL, xbdev->nodename, "pause"))
+		return;
+
+	err = blkif_bdev_reopen(be->blkif);
+	if (err)
+		xenbus_dev_fatal(xbdev, err, "reopening device");
+}
+
 /**
  * Callback received when the hotplug scripts have placed the physical-device
  * node.  Read it and the mode node, and create a vbd.  If the frontend is
@@ -685,12 +703,7 @@
 			if (err)
 				break;
 
-			if (!be->blkif->bdev) {
-				err = blkback_open_bdev(be);
-				if (err)
-					break;
-			}
-
+			blkback_reopen_bdev(be);
 			update_blkif_status(be->blkif);
 		}