3 files changed, 31 insertions, 9 deletions

diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index 30ef7b3..dcfe49f 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -375,7 +375,7 @@ static void purge_persistent_gnt(struct xen_blkif *blkif)
 
 	pr_debug(DRV_PFX "Going to purge %u persistent grants\n", num_clean);
 
-	INIT_LIST_HEAD(&blkif->persistent_purge_list);
+	BUG_ON(!list_empty(&blkif->persistent_purge_list));
 	root = &blkif->persistent_gnts;
 purge_list:
 	foreach_grant_safe(persistent_gnt, n, root, node) {
@@ -625,6 +625,23 @@ purge_gnt_list:
 			print_stats(blkif);
 	}
 
+	/* Drain pending purge work */
+	flush_work(&blkif->persistent_purge_work);
+
+	if (log_stats)
+		print_stats(blkif);
+
+	blkif->xenblkd = NULL;
+	xen_blkif_put(blkif);
+
+	return 0;
+}
+
+/*
+ * Remove persistent grants and empty the pool of free pages
+ */
+void xen_blkbk_free_caches(struct xen_blkif *blkif)
+{
 	/* Free all persistent grant pages */
 	if (!RB_EMPTY_ROOT(&blkif->persistent_gnts))
 		free_persistent_gnts(blkif, &blkif->persistent_gnts,
@@ -635,14 +652,6 @@ purge_gnt_list:
 
 	/* Since we are shutting down remove all pages from the buffer */
 	shrink_free_pagepool(blkif, 0 /* All */);
-
-	if (log_stats)
-		print_stats(blkif);
-
-	blkif->xenblkd = NULL;
-	xen_blkif_put(blkif);
-
-	return 0;
 }
 
 /*
diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h
index 8d88075..f733d76 100644
--- a/drivers/block/xen-blkback/common.h
+++ b/drivers/block/xen-blkback/common.h
@@ -376,6 +376,7 @@ int xen_blkif_xenbus_init(void);
 irqreturn_t xen_blkif_be_int(int irq, void *dev_id);
 int xen_blkif_schedule(void *arg);
 int xen_blkif_purge_persistent(void *arg);
+void xen_blkbk_free_caches(struct xen_blkif *blkif);
 
 int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt,
 			      struct backend_info *be, int state);
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index c2014a0..8afef67 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -125,6 +125,7 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid)
 	blkif->persistent_gnts.rb_node = NULL;
 	spin_lock_init(&blkif->free_pages_lock);
 	INIT_LIST_HEAD(&blkif->free_pages);
+	INIT_LIST_HEAD(&blkif->persistent_purge_list);
 	blkif->free_pages_num = 0;
 	atomic_set(&blkif->persistent_gnt_in_use, 0);
 
@@ -259,6 +260,17 @@ static void xen_blkif_free(struct xen_blkif *blkif)
 	if (!atomic_dec_and_test(&blkif->refcnt))
 		BUG();
 
+	/* Remove all persistent grants and the cache of ballooned pages. */
+	xen_blkbk_free_caches(blkif);
+
+	/* Make sure everything is drained before shutting down */
+	BUG_ON(blkif->persistent_gnt_c != 0);
+	BUG_ON(atomic_read(&blkif->persistent_gnt_in_use) != 0);
+	BUG_ON(blkif->free_pages_num != 0);
+	BUG_ON(!list_empty(&blkif->persistent_purge_list));
+	BUG_ON(!list_empty(&blkif->free_pages));
+	BUG_ON(!RB_EMPTY_ROOT(&blkif->persistent_gnts));
+
 	/* Check that there is no request in use */
 	list_for_each_entry_safe(req, n, &blkif->pending_free, free_list) {
 		list_del(&req->free_list);